ABCMdb

ABCG2 p.Asp620Asn

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Publications

PMID: 12642696 [PubMed] Honjo Y et al: "Single-nucleotide polymorphism (SNP) analysis in the ABC half-transporter ABCG2 (MXR/BCRP/ABCP1)."

No. Sentence Comment

6 Nonsynonymous SNPs at nucleotide 238 (V12M; exon 2) and nucleotide 625 (Q141K; exon 5) showed a greater frequency of heterozygosity (22.2% and 10%) than the SNP at 2062 (D620N; exon 16). Login to comment
104 Amplification in the MCF-7 SINGLE-NUCLEOTIDE POLYMORPHISM (SNP) ANALYSIS IN THE ABC HALF-TRANSPORTER ABCG2 (MXR/BCRP/ABCP1) www.landesbioscience.com Cancer Biology & Therapy 699 Table 2 PRIMERS USED IN SEQUENCING 90 DNA SAMPLES Forward Primer (5`-> 3`) Reverse Primer (5`-> 3`) Exon 1 TGCCCACTCAAAAGGTTC CCAACCCACACTTAACACAC Exon 2 TGTCACCTAGTGTTTGCAATC GCCAGTTTCTTGGAAATAGCC Exon 3 AATCCTGCTTTGGTCTCC TCTCCCATTCTTTTTCCTC Exon 4 AGCATGTGTTGGAGGGAAAA ATCAGCCAAAGCACTTACCC Exon 5 GCAGGCTTTGCAGACATCTA TGCTGATCATGATGCTTTCA Exon 6 TCTTACAGGACTGGCACACG CCCCAAGAATATCTGGGACA Exon 7 TCAGGCTGAACTAGAGCAAACA CAAACAGCACTCCTGCAGAC Exon 8 CATGGGAAGAAGAGAGAAAG GTTGACTGGTATCAGAAGAC Exon 9 ACTCCTGACCTCGTAATCC GAAGCAGATGATAACAGAACC Exon 10 TCTAATTGAAACTCTTCCCC AGTTCGAAGCCAGTCTAGC Exon 11 TGAGTTGACTGCGGTGATTT GTAATCCTCCGGATCCCATC Exon 12 GTCTAGCCCTGAGGATGTGG TGCAAAATGGACAGGTGTTT Exon 13 CAGACACAACATTGGAGAC TAAGGGCAAAGAGGAAAG Exon 14 CTGCATGAAATTACTCAAGC CCATCCTCTCATTTACTTCC Exon 15 AAACTGTTTACCTTGCCC GCACCTCACTTCAATCTC Exon 16 GAGTAACATTTGACGGATG CTCTACTCTACCCACAGTTC Table 3 RESULTS OF SNP ANALYSIS OF 16 EXONS ENCODING ABCG2* Wild-type Frequency Frequency Frequency Amino Acid Exon Nucleotide+ allele SNP Wt/Wt Wt/Var Var/Var aa# 1 91 C T 98.9% 1.1% Noncoding 175 A G 97.8% 2.2% Noncoding 2 238 G A 76.7% 22.2% 1.1% 12 Val to Met 5 625 C A 88.9% 10% 1.1% 141 Gln to Lys 9 1302 G A 97.8% 2.2% 366 Glu to Glu 12 1629 A G 98.9% 1.1% 475 Leu to Leu 16 2062 G A 98.9% 1.1% 620 Asp to Asn 2597 C A 98.9% 1.1% Noncoding Intronic Variants 2 +36** A G 76.7% 22.2% 1.1% 6 -16 A G 88.9% 8.9% 2.2% 7 -20 T A 98.9% 1.1% +18 A G 93.3% 5.6% 1.1% 11 +20 A G 63.3% 27.8% 8.9% 12 +49 G T 75.6% 22.2% 2.2% 14 -21 C T 67.8% 28.9% 3.3% *Identified SNPs are recorded in the table with all 16 exons sequenced in 90 DNA samples. Login to comment

PMID: 14754410 [PubMed] Han B et al: "Multidrug resistance in cancer chemotherapy and xenobiotic protection mediated by the half ATP-binding cassette transporter ABCG2."

No. Sentence Comment

108 Nonsynonymous SNPs at nucleotide 238 (Val12 Met; exon 2) and nucleotide 625 (Gln141 Lys; exon 5) showed a greater frequency of heterozygosity (22.2% and 10%, respectively) than the SNP at 2062 (Asp620 Asn; exon 16). Login to comment

PMID: 15743976 [PubMed] Vethanayagam RR et al: "Functional analysis of the human variants of breast cancer resistance protein: I206L, N590Y, and D620N."

No. Sentence Comment

1 In this study, the effects of the I206L, N590Y, and D620N variants on protein expression, plasma membrane localization, and transport activity of BCRP were investigated. Login to comment
4 The expression level of I206L in the plasma membrane was approximately 45% of that of wild-type protein, whereas the N590Y and D620N levels were increased approximately 3.6-fold and 2.4-fold, respectively, as determined by immunoblotting. All three variants transported mitoxantrone, pheophorbide a, and BODIPY FL-prazosin. Login to comment
5 After normalization for differences in BCRP expression, I206L, N590Y, and D620N exhibited approximately 2-fold, 0.3-fold, and 0.5-fold wild-type efflux activities, respectively. Login to comment
8 Although D620N conferred a topotecan resistance similar to that of the wild-type protein, its level of mitoxantrone resistance was decreased by 50%. Login to comment
9 After normalization to BCRP expression levels, ATPase activities of I206L were not significantly different from those of wild-type protein, whereas N590Y and D620N exhibited approximately 30% and 50% of wild-type ATPase activities, respectively. Login to comment
10 These results suggest that I206L has the lowest protein expression and the highest activity, whereas N590Y and D620N display higher expression and lower activity, relative to wild-type BCRP. Login to comment
21 Other variants such as I206L, N590Y, and D620N are generally much less frequent, with allele frequencies of approximately 1% or less (Honjo et al., 2002; Zamber et al., 2003). Login to comment
29 Functional analysis of the I206L, N590Y, and D620N variants of BCRP has not been reported so far. Login to comment
30 In the present study, we stably expressed wild-type BCRP and the variants I206L, N590Y, and D620N in HEK cells and analyzed the effects of the variants on BCRP expression, plasma membrane localization, transport, and ATPase activities, as well as drug resistance characteristics. Login to comment
45 The variants I206L, N590Y, and D620N were then generated using the QuickChange Site-directed Mutagenesis Kit (Stratagene) and the pBluescript SK(ϩ) plasmid carrying wild-type BCRP cDNA as a template, according to the manufacturer`s instructions. Login to comment
47 The primer pairs for I206L were 5Ј-CTTATCACTGATCCTTCCCTCTTGTTCTTGGATGAG-3Ј and 5ЈCTCATCCAAGAACAAGAGGGAAGGATCAGTGATAAG-3Ј; the primer pairs for N590Y were 5Ј-GA- ATTTTTGGGACAATACTTCTGCCCAGGACTC-3Ј and 5Ј-GAGTCCT- GGGCAGAAGTATTGTCCCAAAAATTC-3Ј; and the primer pairs for D620N were 5Ј-GTAAAGCAGGGCATCAATCTCTCACCCTGGGGC-3Ј and 5Ј-GCCCCAGGGTGAGAGATTGATGCCCTGCTTTAC-3Ј. Login to comment
128 Results Stable Expression of Wild-Type BCRP and the I206L, N590Y, and D620N Variants in HEK Cells. Login to comment
129 To examine the effects of I206L, N590Y, and D620N on protein expression, plasma membrane localization, and function of BCRP, we generated the three variants by site-directed mutagenesis. Login to comment
133 Figure 1A shows a typical immunoblot of whole cell lysates prepared from various cell lines (482R-13, 482R-21, I206L-13, I206L-20, N590Y-1, N590Y-13, D620N-9, and D620N-10) that express the highest levels of BCRP. Login to comment
134 The cell lines 482R-21, I206L-13, N590Y-1, and D620N-9 were used in all subsequent experiments. Login to comment
136 Expression levels of wild-type BCRP and its variants I206L, N590Y, and D620N in stably transfected HEK cells. Login to comment
143 A typical immunoblot of the plasma membrane preparations showed that I206L, N590Y, and D620N were expressed at levels of approximately 0.45-fold, 3.6-fold, and 2.4-fold those of the wild-type protein (482R), respectively (Fig. 1B). Login to comment
148 The I206L, N590Y, and D620N Variants Were Predominantly Routed to the Plasma Membrane. Login to comment
149 To explore whether the variants might influence plasma membrane localization of BCRP, the 482R-21, I206L-13, N590Y-1, and D620N-9 cells were examined by immunofluorescent confocal microscopy. Login to comment
150 Cells transfected with cDNAs of wild-type BCRP (482R-21) and the three variants (I206L-13, N590Y-1, and D620N-9) showed strong plasma membrane staining (Fig. 2), suggesting that, similar to wild-type BCRP, all three variants were predominantly routed to the plasma membrane. Login to comment
153 To further confirm cell surface expression of the variants, the 482R, I206L, N590Y, and D620N cells were incubated with the phycoerythrin-labeled anti-BCRP surface mAb 5D3 and the IgG negative control. Login to comment
158 The relative levels of I206L, N590Y, and D620N on the cell surface were calculated from three independent experiments to be approximately 0.79-fold, 3.1-fold, and 1.3-fold those of wild-type BCRP, respectively. Login to comment
168 Selected areas of HEK cells expressing wild-type BCRP (482R) and the variants I206L, N590Y, and D620N are shown. Login to comment
182 The cells expressing I206L exhibited apparent efflux activities comparable to those of the cells expressing wild-type BCRP for all three fluorescence compounds tested, whereas the cells expressing N590Y and D620N showed higher efflux activities. Login to comment
184 After normalization, the efflux activities of I206L were approximately 2to 3-fold those of wild-type BCRP for the three fluorescent substrates, and the efflux activities were reduced by approximately 60 to 70% and 40 to 50% for N590Y and D620N, respectively (Table 1). Login to comment
197 MX resistance conferred by D620N was decreased by approximately 50%, whereas its level of topotecan resistance remained essentially unchanged. Login to comment
201 A similar pattern of the effects of MX, prazosin, and FTC on the basal ATPase activities of I206L, N590Y, and D620N was observed. Login to comment
203 In contrast, N590Y and D620N exhibited basal ATPase activities and ATPase activities in the presence of MX and prazosin that were approximately 30% and 50% of the wild-type activities, respectively. Login to comment
204 Moreover, the basal ATPase activities of N590Y and D620N and their prazosin-stimulated ATPase activities were significantly different from the respective activities of wild-type BCRP (Fig. 6). Login to comment
223 In the present study, we examined the I206L, N590Y, and D620N TABLE 1 FTC-inhibitable efflux activities of HEK cells expressing wild-type BCRP and its variants The FTC-inhibitable efflux activities of fluorescent compounds are represented by the differences (⌬F) in the median fluorescence between the FTC/efflux histograms and the efflux histograms. Login to comment
228 MX PhA BODIPY-Prazosin Rhodamine 123 (⌬F) ⌬F Ratio ⌬F Ratio ⌬F Ratio pcDNA 0 11.4 Ϯ 7.1 0 0 482R-21 42.5 Ϯ 8.4 1.0 121.9 Ϯ 27.5 1.0 127.0 Ϯ 51.5 1.0 0 I206L-13 52.8 Ϯ 3.0 2.76 131.7 Ϯ 17.3 2.40 127.2 Ϯ 80.2 2.23 0 N590Y-1 64.7 Ϯ 4.7* 0.42 149.3 Ϯ 22.2 0.34 147.5 Ϯ 97.1 0.32 0 D620N-9 67.1 Ϯ 7.1* 0.63 168.2 Ϯ 29.8* 0.55 149.1 Ϯ 68.7 0.47 0 * Indicates that the un-normalized ⌬F values for the 482R cells are significantly different (p Ͻ 0.05) from the N590Y or D620N cells as calculated by Student`s t test. variants. Login to comment
229 I206L, N590Y, and D620N were stably expressed in HEK cells. Login to comment
230 The immunoblots of the plasma membranes revealed a markedly lower protein level for I206L compared with wild-type BCRP, whereas the levels of N590Y and D620N were increased (Fig. 1B). Login to comment
240 The N590Y and D620N variants are predicted to be in the extracellular loop connecting the fifth and sixth TM segments of BCRP. Login to comment
242 The efflux activities of D620N for MX, PhA, and BODIPY-prazosin were also reduced, but to a lesser extent as compared with N590Y (Table 1). Login to comment
243 Whereas D620N conferred resistance to MX at a level approximately 50% of that of wild-type BCRP, its resistance to topotecan was essentially unchanged (Table 2). Login to comment
244 These data indicate that the naturally occurring N590Y and D620N mutations in the extracellular loop can alter function and substrate selectivity of BCRP without significantly affecting cell surface expression, and that a mutation such as D620N in BCRP could affect recognition of one substrate but not the other, likely due to the existence of different ligand binding sites on BCRP, which has been implicated in previous studies (Nakanishi et al., 2003; Gupta et al., 2004). Login to comment
247 The cells expressing wild-type BCRP (Œ), the variants I206L (‚), N590Y (Ⅺ), and D620N (छ), and the vector control cells (F) were exposed to MX (A), topotecan (B), daunorubicin (C), and rhodamine 123 (D) at the various concentrations indicated. Login to comment
256 MX Topotecan Daunorubicin Rhodamine 123 IC50 RR Ratio IC50 RR Ratio IC50 RR IC50 RR nM nM nM nM pcDNA 32.5 Ϯ 3.1 8.5 Ϯ 1.0 34.2 Ϯ 4.1 5797.9 Ϯ 1209.4 482R-21 226.3 Ϯ 27.4 7.0 1.0 122.8 Ϯ 23.3 14.4 1.0 40.0 Ϯ 1.7 1.2 10281.0 Ϯ 1445.4 1.7 I206L-13 209.7 Ϯ 19.5 6.5 2.06 124.9 Ϯ 17.1 14.7 2.25 25.6 Ϯ 2.8 0.7 8829.4 Ϯ 1454.8 1.5 N590Y-1 287.9 Ϯ 24.0* 8.9 0.35 130.5 Ϯ 17.8 15.4 0.30 19.9 Ϯ 2.3 0.6 7867.9 Ϯ 3691.1 1.3 D620N-9 271.9 Ϯ 33.3* 8.4 0.48 278.3 Ϯ 18.9* 32.7 0.91 31.6 Ϯ 1.8 0.9 15469.3 Ϯ 1762.5 2.6 * Indicates that the un-normalized IC50 values of the 482R cells are significantly different (p Ͻ 0.05) from the N590Y or D620N cells as calculated by Student`s t test. ATPase activities of both N590Y and D620N were also decreased to approximately 30 to 50% of the wild-type activities (Fig. 6). Login to comment
261 Our data, demonstrating that the efflux activities and drug resistance capabilities of N590Y and D620N, except for the topotecan resistance, are decreased, indicate that amino acid changes in the extracellular loop of BCRP can selectively affect function of the transporter. Login to comment
265 However, the immunoblots of both whole cell lysates and the plasma membranes did not illustrate any reduction or increase in molecular weight of N590Y and D620N compared with wild-type protein (Fig. 1). Login to comment
266 These results rule out the possibility that N590Y and D620N would be involved in N-glycosylation. Login to comment
267 Interestingly, ATPase activities of N590Y and D620N were coincidentally impaired as the transport activities, even though the two mutations are not within the NBD. Login to comment
269 These data suggest that, whereas ATPase activities of BCRP could be affected by mutations in the NBD (e.g., Q141K and I206L), mutations in other regions including the TM segments (e.g., G406L/G410L) and extracellular loops (e.g., N590Y and D620N) can also influence ATP hydrolysis. Login to comment
272 The D620N variant was detected in 1.1% of all DNA samples examined with unknown genetic origin (Honjo et al., 2002). Login to comment
273 The in vitro analysis in this study revealed that, after normalization to the BCRP expression levels, the specific activities of I206L, N590Y, and D620N were significantly altered as compared with wild-type BCRP; however, the overall efflux activities and drug resistance profiles of the cells expressing these variants remained essentially unchanged. Login to comment

PMID: 15838659 [PubMed] Morisaki K et al: "Single nucleotide polymorphisms modify the transporter activity of ABCG2."

No. Sentence Comment

0 ORIGINAL ARTICLE Kuniaki Morisaki Æ Robert W. Robey Csilla O¨ zvegy-Laczka Æ Yasumasa Honjo Orsolya Polgar Æ Kenneth Steadman Bala´ zs Sarkadi Æ Susan E. Bates Single nucleotide polymorphisms modify the transporter activity of ABCG2 Received: 21 July 2004 / Accepted: 1 October 2004 / Published online: 19 April 2005 Ó Springer-Verlag 2005 Abstract Single nucleotide polymorphism (SNP) analyses of the ABCG2 gene have revealed three nonsynonymous SNPs resulting in the amino acid changes at V12M, Q141K and D620N. Login to comment
4 Values for V12M and D620N ABCG2 were comparable to those for wild-type R482 ABCG2. Login to comment
6 Basal ATPase activity in cells transfected with Q141K ABCG2 was 1.8-fold lower than in cells transfected with wild-type ABCG2, but was comparable among cells expressing wild-type, V12M or D620N ABCG2. Login to comment
30 We previously sequenced the ABCG2 gene in 90 genomic DNA samples representing a global genetic diversity and identified three nonsynonymous SNPs -34G fi A, substituting a valine for methionine (V12M); 421C fi A, substituting a glutamine for lysine (Q141K); and 1858C fi A, substituting an aspartic acid for asparagine (D620N)-in the coding region of ABCG2 [18]. Login to comment
37 containing full-length ABCG2 encoding wild-type (R482), mutant (R482T, R482G), or SNP variants (V12M, Q141K, or D620N) of ABCG2. Login to comment
98 Clones were initially screened using the anti-ABCG2 antibody 5D3 and, from the positive clones obtained, 12 clones transfected with V12M, Q141K, D620N, or 1_11delV12M were selected for further study: V12M-12, -13 and -14; Q141K-5, -8, -13 and -16; D620N-2, -3 and -23; and 1_11delV12M-2 and -8. Login to comment
100 By Northern blot and immunoblot analysis, D620N- 3 and D620N-23 showed relatively low expression levels (Fig. 1a, b). Login to comment
108 a Northern blot analysis of ABCG2 expression in representative HEK-293 cells transfected with wild-type, V12M, Q141K, or D620N ABCG2. Login to comment
122 Representative results are shown clones each of ABCG2-transfected cells expressing R482, R482T, R482G, V12M, Q141K or D620N ABCG2. Login to comment
133 Efflux and expression values for cells transfected with V12M and D620N ABCG2 fell close to the line, while values for cells transfected with Q141K ABCG2 fell predominantly below the line. Login to comment
135 Among the transfectants, Q141K variants showed significantly lower values compared to the transfectants with wild-type ABCG2 and the other SNP variants, V12M and D620N (P=0.0048, 0.0005, and 0.0126, respectively), suggesting that Q141K ABCG2 transports mitoxantrone less efficiently than wild-type ABCG2. Login to comment
136 Although V12M and D620N variants showed somewhat higher efficiency of mitoxantrone transport than 482R, no statistically significant difference was found. Login to comment
140 We next examined the ATPase activity of V12M, Q141K, and D620N variants using this system. Login to comment
163 To examine whether the nonsynonymous SNPs in ABCG2 affect the transport of this compound, Hoechst 33342 dye transport was measured in intact Sf9 cells expressing wild-type, V12M, Q141K, or D620N ABCG2, as well as the nonfunctional mutant, R482G/K86M. Login to comment
164 Immunoblot analysis of protein obtained from the infected cells is shown in Fig. 7a. Hoechst 33342 transport was comparable in cells expressing wild-type, Q141K or D620N ABCG2. Login to comment
172 Representative histograms for 482R-9, 482G-1, V12M-13, D620N-2, Q141K-5, and 1_11delV12M-8 are shown substrate-free medium for 60 min continuing with or without FTC. Login to comment
178 Discussion We and others have recently identified several polymorphisms in ABCG2, including three nonsynonymous SNPs resulting in amino acid substitution in the coding region of ABCG2: V12M, Q141K, D620N [4, 19, 20, 50]. Login to comment
189 Values from the experiment in a were obtained for ABCG2-transfected HEK-293 clones expressing varying levels of 482R, R482G, R482T, V12M, Q141K, and D620N ABCG2 and a box plot was generated. Login to comment
205 a Immunoblot detection of human wild-type, D620N, Q141K and V12M ABCG2 expressed in Sf9 insect cells. Login to comment
206 Membranes of Sf9 cells (1.5 lg total protein from V12M/Sf9, Q141K/Sf9 and D620N/Sf9, 1.0 lg from wild-type ABCG2/Sf9, and 1.2 lg from b-galactosidase/Sf9) dissolved in disaggregation buffer were subjected to electrophoresis on 7.5% Laemmli-type gels and blotted onto PVDF membranes, followed by immunodetection with the BXP-21 antibody. b ATPase activity measured in membranes of Sf9 cells expressing the wild-type, V12M, Q141K, and D620N variants of human ABCG2. Login to comment
212 When surface ABCG2 expression was used to normalize the FTC-inhibitable mitoxantrone efflux, we found that HEK-293 cells expressing Q141K ABCG2 transported mitoxantrone less efficiently than cells expressing wild-type, V12M or D620N ABCG2. Login to comment

PMID: 15882131 [PubMed] Lepper ER et al: "Mechanisms of resistance to anticancer drugs: the role of the polymorphic ABC transporters ABCB1 and ABCG2."

No. Sentence Comment

157 Position in gene* Nucleotide‡ Region Wild-type allele Variant allele Amino acid Change -19572 to -19569 5`-Flanking region CTCA - CTCA deletion -19202 5` UTR G C -18845 5` UTR T C -18604 5` UTR A - Deletion -18482 -113 Exon 1 C T Non-coding -18398 -29 Exon 1 A G Non-coding 34 34 Exon 2 G A 12 Val to Met 71 71 Exon 2 C T 24 Ala to Val 114 114 Exon 2 T C 38 Synonymous 239 Intron 2 A G 7268 Intron 2 T C 7420 Intron 3 - T Insertion 8007 Intron 3 G A 8184 369 Exon 4 C T 123 Synonymous 8191 376 Exon 4 C T 126 Gln to Term 8825 421 Exon 5 C A 141 Gln to Lys 8862 458 Exon 5 C T 153 Thr to Met 8878 474 Exon 5 C T 158 Synonymous 8900 496 Exon 5 C G 166 Gln to Glu 18186 Intron 5 A G 18286 616 Exon 6 A C 206 Ile to Leu 18293 623 Exon 6 T C 208 Phe to Ser 21530 Intron 6 C T 21718 Intron 6 A G 21903 Intron 7 A G 24618 Intron 7 T A 26297 1098 Exon 9 G A 366 Synonymous 38389 1291 Exon 11 T C 431 Phe to Leu 38485 Intron 11 A G 40111 Intron 11 G A 40303 1425 Exon 12 A G 475 Synonymous 40322 1444 Exon 12 A G 482 Arg to Gly 40323 1445 Exon 12 G C 482 Arg to Thr 40343 1465 Exon 12 T C 489 Phe to Leu 40419 Intron 12 G T 42314 Intron 13 T G 44997 Intron 14 A G 45022 Intron 14 C T 45073 1768 Exon 15 A T 590 Asn to Tyr 47355 1858 Exon 16 G A 620 Asp to Asn 47734 2237 Exon 16 G T Non-coding 47890 2393 Exon 16 G T Non-coding 47891 2394 Exon 16 C A Non-coding ABC: ATP-binding cassette; UTR: Untranslated region. Login to comment

PMID: 16146333 [PubMed] Mao Q et al: "Role of the breast cancer resistance protein (ABCG2) in drug transport."

No. Sentence Comment

161 For example, in a Japanese population studied, 39% to 50% are heterozygous and 7% are homozygous for the variant Q141K.95,96 In a Chinese population, 60% are heterozygous for Q141K.95 Several other variants such as I206L, N590Y, and D620N are much less frequent with allele frequencies of ~1%.95,97 For instance, N590Y is present in ~1.5% of Caucasians.95 I206L is found only in Hispanic populations so far.95 D620N is detected in 1.1% of all DNA samples examined with unknown genetic origin.97 In addition, a polymorphism in exon 4 that results in a substitution of stop codon for Gln at position 126 has also been identified.96 Amino acid changes at position 482 that were found in some drug-selected resistant cell lines have so far not been identified in normal populations or in DNA samples from cancer patients.49 In vitro functional characterization of the variants V12M and Q141K produced contradicting results. Login to comment

PMID: 16160819 [PubMed] Ishikawa T et al: "Pharmacogenomics of the human ABC transporter ABCG2: from functional evaluation to drug molecular design."

No. Sentence Comment

88 These SNPs showed higher allele frequencies than does the SNP D620N (Table 2). Login to comment
113 These contradictory expression and localization data for ABCG2 variants indicate that differences in transfection conditions (transient or stable expression), the copy number of cDNA incorporated in genomic DNA or other cellular determinants may variably Table 2 Frequencies of ABCG2 alleles in different ethnic groups Position Ethnic group Variant allele Allele Reference Amino acid cDNA N Hetero Homo Frequency (%) V12M c.34G>A Japanese 29 9 1 19.0 Imai et al. (2002) Japanese 10 - - 15.0 Zamber et al. (2003) Japanese 220 61 8 17.5 Kobayashi et al. (2005) Chinese 10 - - 20.0 Zamber et al. (2003) Southeast Asians 10 - - 45.0 Zamber et al. (2003) Pacific Islanders 7 - - 64.0 Zamber et al. (2003) Swedish 60 2 0 1.7 B¨ackstr¨om et al. (2003) Dutch 100 11 1 6.5 Bosch et al. (2005) Caucasian 86 - - 2.0 Zamber et al. (2003) Caucasian 150 27 2 10.3 Mizuarai et al. (2004) Caucasian 150 11 0 3.7 Kobayashi et al. (2005) Ashkenazi Jewish 10 - - 10.0 Zamber et al. (2003) Middle Eastern 20 - - 5.0 Zamber et al. (2003) Africans North of Sahara 7 - - 14.0 Zamber et al. (2003) African American 150 17 1 6.3 Kobayashi et al. (2005) Mexicans 10 - - 10.0 Zamber et al. (2003) Hispanic Livers 5 - - 40.0 Zamber et al. (2003) Mexican Indians 5 - - 90.0 Zamber et al. (2003) Q126Stop c.376C>T Japanese 124 3 0 1.2 Imai et al. (2002) Japanese 60 2 0 1.7 Itoda et al. (2003) Japanese 220 4 0 0.9 Kobayashi et al. (2005) Caucasian 150 0 0 0.0 Mizuarai et al. (2004) Caucasian 150 0 0 0.0 Kobayashi et al. (2005) African American 150 0 0 0.0 Kobayashi et al. (2005) Q141K c.421C>A Japanese 124 48 9 26.6 Imai et al. (2002) Japanese 10 - - 35.0 Zamber et al. (2003) Japanese 220 90 27 32.7 Kobayashi et al. (2005) Chinese 95 43 11 34.2 de Jong et al. (2004) Chinese 10 - - 35.0 Zamber et al. (2003) Southeast Asians 10 - - 15.0 Zamber et al. (2003) Pacific Islanders 7 - - 14.0 Zamber et al. (2003) Swedish 60 10 1 10.0 B¨ackstr¨om et al. (2003) Dutch 100 20 2 12.0 Bosch et al. (2005) Caucasian 85 - - 14.0 Zamber et al. (2003) Caucasian 172 33 3 11.3 de Jong et al. (2004) Caucasian 150 22 2 8.7 Mizuarai et al. (2004) Caucasian 150 25 4 11.0 Kobayashi et al. (2005) Ashkenazi Jewish 10 - - 5.0 Zamber et al. (2003) Middle Eastern 20 - - 13.0 Zamber et al. (2003) Africans North of Sahara 7 - - 0.0 Zamber et al. (2003) African, Sub-Saharan 938 14 1 0.9 de Jong et al. (2004) African American 24 - - 0.0 Zamber et al. (2003) African American 150 5 1 2.3 Kobayashi et al. (2005) African American 94 8 1 5.3 de Jong et al. (2004) Mexicans 10 - - 5.0 Zamber et al. (2003) Hispanic Livers 5 - - 10.0 Zamber et al. (2003) Mexican Indians 5 - - 10.0 Zamber et al. (2003) R160Q c.479G>A Dutch 100 1 0 0.5 Bosch et al. (2005) I206L c.616A>C Japanese 10 - - 0.0 Zamber et al. (2003) Chinese 10 - - 0.0 Zamber et al. (2003) Southeast Asians 10 - - 0.0 Zamber et al. (2003) Pacific Islanders 7 - - 0.0 Zamber et al. (2003) Caucasian 65 - - 0.0 Zamber et al. (2003) Table 2 Continued Position Ethnic group Variant allele Allele Reference Amino acid cDNA N Hetero Homo Frequency (%) Ashkenazi Jewish 10 - - 0.0 Zamber et al. (2003) Middle Eastern 20 - - 0.0 Zamber et al. (2003) Africans North of Sahara 7 - - 0.0 Zamber et al. (2003) African American 15 - - 0.0 Zamber et al. (2003) Mexicans 10 - - 0.0 Zamber et al. (2003) Hispanic Livers 5 - - 10.0 Zamber et al. (2003) Mexican Indians 5 - - 0.0 Zamber et al. (2003) F431L c.1291T>C Japanese 60 1 0 0.8 Itoda et al. (2003) S441N c.1322G>A Japanese 100 1 0 0.5 Kobayashi et al. (2005) F489L c.1465T>C Japanese 60 1 0 0.8 Itoda et al. (2003) Japanese 100 1 0 0.5 Kobayashi et al. (2005) R575Stop c.1723C>T Dutch 100 1 0 0.5 Bosch et al. (2005) N590Y c.1768A>T Caucasian 65 - - 1.0 Zamber et al. (2003) Caucasian 150 1 0 0.3 Mizuarai et al. (2004) African Americans 15 - - 0.0 Zamber et al. (2003) D620N c.1858G>A Dutch 100 1 0 0.5 Bosch et al. (2005) affect the cellular processing and sorting of these proteins. Login to comment
118 For this purpose, we have created variant forms of ABCG2 (V12M, G51C, Q126stop, Q141K, T153M, Q166E, I206L, E334stop, N590Y, D620N, R482G, and R482T) by site-directed mutagenesis. Login to comment
130 After the normalization of expression levels, the V12M and T153M variants showed increased levels of MTX transport activity, whereas the I206L, N590Y, and D620N variants had lower transport activities. Login to comment

PMID: 16259577 [PubMed] Sakurai A et al: "Genetic polymorphisms of ATP-binding cassette transporters ABCB1 and ABCG2: therapeutic implications."

No. Sentence Comment

210 In different ethnic groups, seven naturally-occurring non-synonymous SNPs have been reported: V12M, Q126Stop, Q141K, I206L, F431L, S441N, F489L, N590Y and D620N. Login to comment
213 Some of the above sequence variations showed an allele frequency of ~ 1% in distinct populations, Q126stop and F489L in the Japanese and N590Y in the Caucasian population [129-131,134,135], whereas most of the mutations were only detected in single individuals (e.g., I206L, F431L, S441N, D620N). Login to comment
216 These SNPs showed a greater frequency of heterozygosity (22.2 and 10%) than did the SNP at nucleotide 2062 (D620N, exon 16). Login to comment
250 COOH H2N N590Y V12M G51C Q126stop Q141K T153M Q166E I206L F208S S248P E334stop F431L F489L D620N R482G R482T S441N F571I EXTRACELLULAR INTRACELLULAR R160Q R575stop ATP-binding site (transient or stable expression), the copy number of cDNA incorporated in genomic DNA or other cellular determinants may variably affect the cellular processing and sorting of these proteins. Login to comment
255 For this purpose, variant forms of ABCG2 (V12M, G51C, Q126stop, Q141K, T153M, Q166E, I206L, E334stop, N590Y, D620N, R482G and R482T) were created by site-directed mutagenesis (Figure 3). Login to comment
267 The V12M and T153M variants showed increased levels of MTX transport activity, whereas the I206L, N590Y and D620N variants had lower transport activities. Login to comment

PMID: 16303243 [PubMed] Yanase K et al: "Functional SNPs of the breast cancer resistance protein-therapeutic effects and inhibitor development."

No. Sentence Comment

92 Therefore, we first Table 3 SNPs within the BCRP gene Variation Region Effect Domain A-1379G 50 -flanking (promoter) - D-654-651 50 -flanking (promoter) - G-286C 50 -flanking (promoter) - T-476C Exon 1 (50 - UTR) - D-235A Exon 1 (50 - UTR) - A-113G Exon 1 (50 - UTR) - A-29G Exon 1 (50 - UTR) - G34A Exon 2 V12M N-terminal T114C Exon 2 No change N-terminal G151T Exon 2 G51C N-terminal C369T Exon 4 No change NBD C376T Exon 4 Q126stop NBD C421A Exon 5 Q141K NBD C458T Exon 5 T153M NBD C474T Exon 5 No change NBD C496G Exon 5 Q166E NBD A564G Exon 6 No change NBD A616C Exon 6 I206L NBD T623C Exon 6 F208S NBD T742C Exon 7 S248P Linker G1000T Exon 9 E334stop Linker G1098A Exon 9 No change Linker T1291C Exon 11 F431L TMD A1425G Exon 12 No change TMD T1465C Exon 12 F489L TMD A1768T Exon 15 N590Y TMD G1858A Exon 16 D620N TMD G2237T Exon 16 (30 - UTR) - G2393T Exon 16 (30 - UTR) - Abbreviations: UTR, untranslated region; NBD, nucleotide-binding domain; TMD, transmembrane domain. Login to comment

PMID: 16337740 [PubMed] Cervenak J et al: "The role of the human ABCG2 multidrug transporter and its variants in cancer therapy and toxicology."

No. Sentence Comment

109 To date, altogether eight non-synonymous (V12M, Q141K, I206L, F431L, S441N, F489L, N590Y, D620N), five synonymous (silent) (c.114TOC, c.369COT, c.474COT, c.1098GOA, c.1425AOG) missense mutations, one nonsense (Q126X), and one frameshift (c.1515delC) mutations were identified in the coding region of ABCG2 in healthy individuals or in patients [43-46,49,63-65]. Login to comment
112 Some of the above sequence variations showed an allele frequency of about 1% in distinct populations (Q126X, F489L in the Japanese and N590Y in the Caucasian population [45-47,49,64]), while most of the mutations were only detected in single individuals (missense mutations: I206L, F431L, S441N, D620N, and a frameshift mutation: c.1515delC [44-46,49]). Login to comment
164 On the other hand, the V12M (and D620N) ABCG2 showed a similar ATPase activity as the wild-type protein. Login to comment

PMID: 16399366 [PubMed] Ishikawa T et al: "High-speed screening of human ATP-binding cassette transporter function and genetic polymorphisms: new strategies in pharmacogenomics."

No. Sentence Comment

115 For this purpose, variant forms (V12M, G51C, Q126stop, Q141K, T153M, Q166E, I206L, E334stop, N590Y, D620N, R482G, and R482T) have been created by site‐ directed mutagenesis with the QuikChange site‐directed mutagensis kit (Stratagene, La Jolla, CA). Login to comment

PMID: 16454695 [PubMed] Tian Q et al: "Topotecan is a substrate for multidrug resistance associated protein 4."

No. Sentence Comment

47 However, resistance levels of TPT are inconsistent in different BCRP overexpressing cell lines [51-59], probably due to the existence of three mutant variants of BCRP resulting in the amino acid changes at V12M, Q141K and D620N [63-67]. Login to comment

PMID: 16608919 [PubMed] Tamura A et al: "Functional validation of the genetic polymorphisms of human ATP-binding cassette (ABC) transporter ABCG2: identification of alleles that are defective in porphyrin transport."

No. Sentence Comment

2 In the present study, based on the currently available data on SNPs and acquired mutations, we have created a total of 18 variant forms of ABCG2 (V12M, G51C, Q126stop, Q141K, T153M, Q166E, I206L, F208S, S248P, E334stop, F431L, S441N, R482G, R482T, F489L, F571I, N590Y, and D620N) by site-directed mutagenesis and expressed them in insect cells. Login to comment
82 GC indicates the percentage of guanine and cytosine contents in the PCR primer set. Tm shows the melting temperature (Tm) for each PCR primer set. Variant and Primers Primer Sequence (5Ј 3 3Ј) Primer Length GC Tm bases % °C V12M 33 39 55 Forward CGAAGTTTTTATCCCAATGTCACAAGGAAACAC Reverse GTGTTTCCTTGTGACATTGGGATAAAAACTTCG G51C 42 35 59 Forward ATCGAGTAAAACTGAAGAGTTGCTTTCTACCTTGTAGAAAAC Reverse GTTTTCGACAAGGTAGAAAGCAACTCTTCAGTTTTACTCGAT Q126stop 40 40 62 Forward GTAATTCAGGTTACGTGGTATAAGATGATGTTGTGATGGG Reverse CCCATCACAACATCATCTTATACCACGTAACCTGAATTAC Q141K 35 42 55 Forward CGGTGAGAGAAAACTTAAAGTTCTCAGCAGCTCTT Reverse AAGAGCTGCTGAGAACTTTAAGTTTTCTCTCACCG T153M 42 40 60 Forward CGGCTTGCAACAACTATGATGAATCATGAAAAAAACGAACGG Reverse CCGTTCGTTTTTTTCATGATTCATCATAGTTGTTGCAAGCCG Q166E 35 42 55 Forward GGATTAACAGGGTCATTGAAGAGTTAGGTCTGGAT Reverse ATCCAGACCTAACTCTTCAATGACCCTGTTAATCC I206L 36 44 59 Forward CTTATCACTGATCCTTCCCTCTTGTTCTTGGATGAG Reverse CTCATCCAAGAACAAGAGGGAAGGATCAGTGATAAG F208S 35 45 55 Forward TGATCCTTCCATCTTGTCCTTGGATGAGCCTACAA Reverse TTGTAGGCTCATCCAAGGACAAGATGGAAGGATCA S248P 35 40 55 Forward TTCATCAGCCTCGATATCCCATCTTCAAGTTGTTT Reverse AAACAACTTGAAGATGGGATATCGAGGCTGATGAA E334stop 35 31 55 Forward TCATAGAAAAATTAGCGTAGATTTATGTCAACTCC Reverse GGAGTTGACATAAATCTACGCTAATTTTTCTATGA F431L 28 60 62 Forward AGCTGGGGTTCTCCTCTTCCTGACGACC Reverse GGTCGTCAGGAAGAGGAGAACCCCAGCT S441N 34 47 59 Forward AACCAGTGTTTCAGCAATGTTTCAGCCGTGGAAC Reverse GTTCCACGGCTGAAACATTGCTGAAACACTGGTT F489L 46 34 62 Forward GAGGATGTTACCAAGTATTATACTTACCTGTATAGTGTACTTCATG Reverse CATGAAGTACACTATACAGGTAAGTATAATACTTGGTAACATCCTC F571I 36 47 61 Forward GTCATGGCTTCAGTACATCAGCATTCCACGATATGG Reverse CCATATCGTGGAATGCTGATGTACTGAAGCCATGAC N590Y 42 38 62 Forward CATAATGAATTTTTGGGACAATACTTCTGCCCAGGACTCAAT Reverse ATTGAGTCCTGGGCAGAAGTATTGTCCCAAAAATTCATTATG D620N 32 56 62 Forward GGTAAAGCAGGGCATCAATCTCTCACCCTGGG Reverse CCCAGGGTGAGAGATTGATGCCCTGCTTTACC veloped by using Western Lighting Chemiluminescent Reagent Plus (PerkinElmer Life and Analytical Sciences, Boston, MA) and detected by Lumino Imaging Analyzer FAS-1000 (Toyobo Engineering, Osaka, Japan). Login to comment
144 For this purpose, based on the currently available data on SNPs and acquired mutations, we generated variant forms (i.e., V12M, G51C, Q126stop, Q141K, T153M, Q166E, I206L, F208S, S248P, E334stop, F431L, S441N, R482G, R482T, F489L, F571I, N590Y, and D620N) by site-directed mutagenesis. Login to comment
214 In the present study, based on the currently available data on SNPs and acquired mutations, we have created a total of 18 variant forms of ABCG2 (V12M, G51C, Q126stop, Q141K, T153M, Q166E, I206L, F208S, S248P, E334stop, F431L, S441N, R482G, R482T, F489L, F571I, N590Y, and D620N) by site-directed mutagenesis and expressed them in insect cells. Login to comment
224 Potential Risk Amino Acid Transport Allele Frequency cDNA Position Located on Exon Allele Data Sourcea Hemato MTX Wild-Type Allele % V12M ϩϩ ϩϩ 2.0-90.0 34 2 G A 1, 2, 4, 5, 7, 8 ૽૽ Q126stop - - 0.0-1.7 376 4 C T 1, 3, 5, 7 Q141K ϩϩ ϩϩ 0.0-35.5 421 5 C A 1, 2, 4, 5, 6, 7, 8 T153M ϩϩ ϩϩ 3.3 458 5 C T 5 R160Q N.D. N.D. 0.5 479 5 G A 8 Q166E ϩϩ ϩϩ N.D. 496 5 C G NCBI dbSNP rs1061017 I206L ϩϩ ϩϩ 10.0 616 6 A C 2 ૽૽ F208S - - N.D. 623 6 T C NCBI dbSNP rs1061018 ૽૽ S248P - - N.D. 742 7 T C NCBI dbSNP rs3116448 ૽૽ E334stop - - N.D. 1000 9 G T NCBI dbSNP rs3201997 F431L ϩϩ - 0.8 1291 11 T C 3 ૽૽ S441N - - 0.5 1322 11 G A 7 ૽ F489L ϩ - 0.5-0.8 1465 12 T C 3, 7 F571L ϩϩ ϩϩ 0.5 1711 14 T A NCBI dbSNP rs9282571 (૽૽) R575stop N.D. N.D. 0.5 1723 14 C T 8 N590Y ϩϩ ϩϩ 0.0-1.0 1768 15 A T 2, 5 D620N ϩϩ ϩϩ 0.5 1858 16 G A 8 Hemato, hematoporphyrin; NCBI, National Center for Biotechnology Information; N.D., not determined; ૽, risk of porphyria; (૽), potential risk is assumed as the lack of transport activity being as a result of a truncated protein. Login to comment

PMID: 16702730 [PubMed] Maekawa K et al: "Genetic variation and haplotype structure of the ABC transporter gene ABCG2 in a Japanese population."

No. Sentence Comment

89 On the other hand, several nonsynonymous SNPs reported in other ethnic groups were not detected: 805CÀT (Pro269Ser) found in Chinese at a 0.037 frequency,20) 1858GÀA (Asp620Asn) in undened (combined) ethnicities14) (0.011) and in a Dutch population21) (0.005), 616AÀC (Ile206Leu) in Hispanics (0.100), and 1768AÀT (Asn590Tyr) in Caucasians (0.010).18) Thus, these SNPs are either ethnic-specic or rare. Login to comment

PMID: 16877258 [PubMed] Wakabayashi K et al: "Human ABC transporter ABCG2 in xenobiotic protection and redox biology."

No. Sentence Comment

176 Based on the currently available data on SNPs and acquired mutations, we have created a total of 18 variant forms of ABCG2 (V12M, G51C, Q126stop, Q141K, T153M, Q166E, I206L, F208S, S248P, E334stop, F431L, S441N, R482G, R482T, F489L, F571I, N590Y, and D620N) by site-directed mutagenesis and expressed them in Sf9 insect cells. Login to comment

PMID: 17015488 [PubMed] Sarkadi B et al: "Human multidrug resistance ABCB and ABCG transporters: participation in a chemoimmunity defense system."

No. Sentence Comment

997 In healthy individuals or patients, altogether eight nonsynonymous (V12M, Q141K, I206L, F431L, S441N, F489L, N590Y, D620N), five synonymous (silent) (c. Login to comment

PMID: 17027309 [PubMed] Li YF et al: "Towards understanding the mechanism of action of the multidrug resistance-linked half-ABC transporter ABCG2: a molecular modeling study."

No. Sentence Comment

182 In sf9 cell, it is expressed on cell surface, but with no ATPase activity [56] L554P TM5 Lowered drug resistance [42] N557D,E TM5 Functional [21] S566Aa ECL (between TM5 and 6) Lowered drug resistance for the cell line [42] N596Q Between TM5 and 6 N-glycosylation site [65] Y605Ca Loop between TM5 and 6 Lowered drug resistance for the cell line [42] D620N Loop between TM5 and 6 SNP polymorphism [22] H630E,L TM6 Functional [21] A632Va TM Lowered drug resistance for the cell line [42] a Mutants not well characterized. Login to comment

PMID: 17228519 [PubMed] Tamura A et al: "Genetic polymorphisms of human ABC transporter ABCG2: development of the standard method for functional validation of SNPs by using the Flp recombinase system."

No. Sentence Comment

142 Finally, the acquired mutants R482G and R482T form another group, which is characteristic Standard method for functional validation of ABCG2 SNPs Journal of Experimental Therapeutics and Oncology Vol. 6 2006 9 Table 3 Remarks mRNA Protein Author Ref Host cell Vector Expression SNP expression expression Imai et al. (15) PA317 pHaL-IRES-DHFR bicistronic Stable V12M Similar to WT Similar to WT - - retrovirus vector plasmid - Q141K Similar to WT Lower than WT Mizuarai et al. (18) LLC-PK1 pcDNA3.1(+) Stable V12M Similar to WT N.D. - - - - Q141K Similar to WT N.D. Morisaki et al. (25) HEK293 pcDNA3.1 Stable V12M Vary among clones Vary among clones - - - - Q141K Vary among clones Vary among clones - - - - D620N Vary among clones Vary among clones Kondo et al. (26) LLC-PK1/ pcDNA3.1/ Stable/ V12M N.D. Similar to WT - HEK293 Adenovirus Transient Q141K N.D. 30 - 40% of WT - - - - A149P N.D. Similar to WT - - - - R163K N.D. Similar to WT - - - - Q166E N.D. Similar to WT - - - - P269S N.D. Similar to WT - - - - S441N N.D. Lower than WT Vethanayagam (27) HEK293 pcDNA3.1/myc-His(-) Stable I206L N.D. Vary among clones et al. - - - - N590Y N.D. Vary among clones - - - - D620N N.D. Vary among clones N.D.: No data Table 2. Login to comment

PMID: 17373578 [PubMed] Yoshioka S et al: "The identification of two germ-line mutations in the human breast cancer resistance protein gene that result in the expression of a low/non-functional protein."

No. Sentence Comment

8 PA/T153M cells (C458T BCRP-transfectants) and PA/D620N cells (G1858A BCRP-transfectants) expressed lower amounts of BCRP and showed lower levels of resistance to SN-38 compared with PA/WT cells. Login to comment
42 The cells were selected with 120 ng/mL of methotrexate, and the resulting mixed populations of resistant cells were designated as PA/WT, PA/V12M, PA/ G51C, PA/Q141K, PA/T153M, PA/I206L, PA/F208S, PA/ S248P, PA/F431L, PA/N590Y and PA/D620N, respectively. The PA/F208S clones and PA/F431L clones were obtained by limiting dilution. Login to comment
43 Cell Growth Inhibition Assay Anticancer agent resistance levels in both the parental PA317 cells and in the various BCRP transfectants were Table I. Frequencies of Germ-line Mutations/SNPs Within The BCRP Gene Variation Frequency (%) Number Population Reference Nucleotide Amino acid G34A V12M 19 29 Japanese 17 G151T G51C 0.1a 350 Japanese C376T Q126Stop 1.2 124 Japanese 17 C421A Q141K 26.6 124 Japanese 17 C458T T153M 3.3 30 Cell line 32 C496G Q166E 0.3a 200 Japanese A616C I206L 20 10 Hispanic 33 T623C F208S 0.3a 200 Japanese T742C S248P 0.5a 200 Japanese T1291C F431L 0.6b 260 Japanese 34 A1768T N590Y 1.1 88 Caucasians 33 G1858A D620N 1.1 90 unknown 35 a Determined in this study. Login to comment
45 V12M Q141K D620N N590Y F431L S248P F208S I206L T153M G51C Q166E OUT MEMBRANE IN Fig. 1. Login to comment
75 SN-38 Resistance Levels of PA317 Transfectantsa Cell type IC50 (nmol/L) Degree of resistance PA317 11 T 0.2 1 PA/WT 550 T 16 50 PA/V12M 490 T 13 45 PA/Q141K 110 T 5.9 10 PA/T153M 260 T 15 24 PA/Q166E 680 T 40 62 PA/F208S 10 T 0.7 1 PA/F431L 34 T 0.9 3 PA/D620N 190 T 5.7 17 a Cells were cultured for 5 days with various concentrations of SN-38. Login to comment
80 RESULTS Expression of BCRP in PA317 Transfectants The germ-line mutations and resulting amino acid substitutions examined in this study were as follows; G151T (G51C), C458T (T153M), C496G (Q166E), A616C (I206L), T623C (F208S), T742C (S248P), T1291C (F431L), A1768T (N590Y) and G1858A (D620N). Login to comment
82 F431L, N590Y and D620N are located within the transmembrane domain (Fig. 1 and Table I). Login to comment
88 PA/T153M and PA/D620N transfectants expressed lower amounts of BCRP than PA/WT cells, but these levels were higher than those in the PA/Q141K cells (Fig. 2a). Login to comment
94 PA/Q141K, PA/T153M and PA/D620N cells expressed lower amounts of BCRP on their cell surfaces than PA/WT cells (Fig. 2d). Login to comment
102 PA/Q141K, PA/ T153M, and PA/D620N cells showed 10Y24-fold higher resistance levels to SN-38 compared with the parental cells (Table II). Login to comment
128 DISCUSSION In our current study, we have examined the effect of the nine germ-line mutations/SNPs, G151T, C458T, C496G, A616C, T623C, T742C, T1291C, A1768T, and G1858A BCRP, resulting in the amino acid changes G51C, T153M, Q166E, I206L, F208S, S248P, F431L, N590Y, D620N, respectively, on BCRP protein expression and function. Login to comment
130 The resulting mixed populations of cells were designated a PA/WT, PA/V12M, PA/G51C, PA/Q141K, PA/ T153M, PA/I206L, PA/F208S, PA/S248P, PA/F431L, PA/ N590Y and PA/D620N. Login to comment
135 PA/ T153M and PA/D620N cells expressed lower levels of BCRP and also showed lower resistance to SN-38, compared with PA/WT cells (Fig. 2a and Table II). Login to comment
143 G51C, T153M, Q166E, I206L, F208S, and S248P are located in the intracellular domain, and F431L, N590Y, and D620N reside in the transmembrane domain. Login to comment
168 Although PA/F431L cells express higher quantities of 70-kDa BCRP compared with PA/Q141K, PA/T153M, and PA/D620N cells (Fig. 2a) these cells in fact show a lower resistance to SN-38 than these other three transfectants (Table II). Login to comment
171 PA/T153M and PA/D620N cells showed low-levels of BCRP expression and drug resistance to SN-38 compared with PA/WT cells (Fig. 2a and Table II). Login to comment
173 Similar results were obtained using NIIH3T3/T153M and NIH3T3/D620N cells (date not shown). Login to comment

PMID: 18154452 [PubMed] Sharom FJ et al: "ABC multidrug transporters: structure, function and role in chemoresistance."

No. Sentence Comment

359 Compared with wild-type ABCG2, the Q141K variant displayed lower ATPase activity and lower mitoxantrone efflux when expressed in HEK-293 cells, whereas the V12M and D620N proteins showed little change [172]. Login to comment

PMID: 18249138 [PubMed] Hazai E et al: "Homology modeling of breast cancer resistance protein (ABCG2)."

No. Sentence Comment

245 However, in our model, R482 cannot form interaction with rhodamine, but L484 is in interacting distance Table 3 Mutations on BCRP and their effect on its function Mutation Effect/results Reference V12M Did not effect Hemato and MTX transport Tamura et al. (2006) G51C Did not effect Hemato and MTX transport Tamura et al. (2006) K86M Inactivates transporter (dominant negative effect on ATPase activity); alters subcellular distribution Henriksen et al. (2005a) K86M Transporter inactive, but still able to bind ATP Ozvegy et al. (2002) Q126stop Defective porphyrin transport Tamura et al. (2006) Q141K Did not effect Hemato and MTX transport Tamura et al. (2006) T153M Did not effect Hemato and MTX transport Tamura et al. (2006) Q166E Did not effect Hemato and MTX transport Tamura et al. (2006) I206L Did not effect Hemato and MTX transport Tamura et al. (2006) F208S Defective porphyrin transport Tamura et al. (2006) S248P Defective porphyrin transport Tamura et al. (2006) E334stop Defective porphyrin transport Tamura et al. (2006) F431L Effects MTX transport Tamura et al. (2006) S441N Defective porphyrin transport Tamura et al. (2006) E446-mutants No drug resistance Miwa et al. (2003) R482G, R482T Effects MTX transport Tamura et al. (2006) R482T Substrate drug transport and inhibitor efficiency is not mediated by changes in drug-binding Pozza et al. (2006) R482G, R482T Substitution influence the substrate specificity of the transporter Ozvegy et al. (2002) R482G, R482T Altered substrate specificity Honjo et al. (2001) R482G Methotrexate not transported Chen et al. (2003b) Mitomo et al. (2003) R482G Resistance to hydrophilic antifolates in vitro, G482-ABCG2 mutation confers high-level resistance to various hydrophilic antifolates Shafran et al., (2005) R482G Three distinct drug, binding sites Clark et al. (2006) R482G Altered substrate specificity, granulocyte maturation uneffected Ujhelly et al. (2003) R482 mutants Higher resistance to mitoxantrone and doxorubicin than wt Miwa et al. (2003) R482X Affects substrate transport and ATP hydrolysis but not substrate binding Ejendal et al. (2006) F489L Impaired porphyrin transport Tamura et al. (2006) G553L; G553E Impaired trafficing, expression, and N-linked glycosylation Polgar et al. (2006) L554P Dominant negative effect on drug sensitivity Kage et al. (2002) N557D Resistance to MTX, but decreased transport of SN-38; N557E no change in transport compared to wt Miwa et al. (2003) F571I Did not effect Hemato and MTX transport Tamura et al. (2006) N590Y Did not effect Hemato and MTX transport Tamura et al. (2006) C592A Impaired function and expression Henriksen et al. (2005b) C592A/C608A Restored plasma mb expression; MTX transport normal, BODIPY-prazosin impaired Henriksen et al. (2005b) C603A Disulfide bridge; no functional or membrane targeting change Henriksen et al. (2005b) C608A Impaired function and expression Henriksen et al. (2005b) D620N Did not effect Hemato and MTX transport Tamura et al. (2006) H630X No change in transport Miwa et al. (2003) Cand N-terminal truncated Impaired trafficing Takada et al. (2005) with the ligand. Login to comment

PMID: 18363541 [PubMed] Tamura A et al: "Drug-induced phototoxicity evoked by inhibition of human ABC transporter ABCG2: development of in vitro high-speed screening systems."

No. Sentence Comment

230 Plasma membrane Outside Inside ATP-binding cassette H2 N COOH V12M G51C Q126stop Q141K T153M R160Q Q166E I206L F208S S248P E334stop F431L F489L S441N R482G R482T F571I R575stop N590Y D620N T542A A528T D296H P269S A. Login to comment
231 0.0 0.1 0.2 0.3 0.4 0.5 Mock WT V12M G51C Q126stop Q141K T153M Q166E I206L F208S S248P E334stop F431L S441N F489L F571I N590Y D620N R482G R482T ATP-dependenthematoporphyrintransport (nmol/min/mgprotein) B. interactions should also take into consideration the presence of multiple flavonoids. Login to comment
245 Based on the presently available data on SNPs and acquired mutations, we have created a total of 18 variant forms of ABCG2 (V12M, G51C, Q126stop, Q141K, T153M, Q166E, I206L, F208S, S248P, E334stop, F431L, S441N, R482G, R482T, F489L, F571I, N590Y, and D620N) by site-directed mutagenesis and expressed them in insect cells. Login to comment
252 Amino acid Porphyrin transport* Allele frequency (%)‡ cDNA position Location Wild-type allele Variant alllele V12M ++ 2.0 - 90.0 34 Exon 2 G A Q126stop - 0.0 - 1.7 376 Exon 4 C T Q141K ++ 0.0 - 35.5 421 Exon 5 C A T153M ++ 3.3 458 Exon 5 C T Q166E ++ N.D. 496 Exon 5 C G I206L ++ 10.0 616 Exon 6 A C F208S - N.D. 623 Exon 6 T C S248P - N.D. 742 Exon 7 T C E334stop - N.D. 1000 Exon 9 G T F431L ++ 0.8 1291 Exon 11 T C S441N - 0.5 1322 Exon 11 G A F489L + 0.5 - 0.8 1465 Exon 12 T C F571L ++ 0.5 1711 Exon 14 T A N590Y ++ 0.0 - 1.0 1768 Exon 15 A T D620N ++ 0.5 1858 Exon 16 G A *Transport of hematoporphyrin is indicated by either '+` (positive) or '-' (negative). Login to comment

PMID: 18464048 [PubMed] Gradhand U et al: "Pharmacogenomics of MRP transporters (ABCC1-5) and BCRP (ABCG2)."

No. Sentence Comment

250 It should be noted that many xeno- and endobiotic BCRP Figure 5 Predicted membrance topology of BCRP (ABCG2) based on hydrophobicity analysis. Locations of the non-synonymous polymorphisms are indicated with arrows. See Table 5 for allele frequencies and description of funtional consequences. NH2 COOH NBD Val12Met Gly51Cys Gln126* Ala149Pro Gln141Lys Thr153Met Arg160Gln Arg163Lys Gln166Glu Phe506Ser Phe507Leu Val508Leu Met509* Phe489Leu Ser441Asn Phe431Leu Glu334* Ile206Leu Ala315del Thr316del Phe208Ser Asp296His Ser248Pro Pro269Ser Phe571Ile Arg575* Asn590Tyr Asp620Asn in out Membrane BCRP (ABCG2) NBD Val12Met NBDNBD Val12Met substrates are also transported by other efflux transporters, especially P-glycoprotein, thus extrapolating BCRP related in vitro data to the in vivo situation may be difficult. Login to comment

PMID: 18598762 [PubMed] Han Y et al: "Modulation of breast cancer resistance protein (BCRP/ABCG2) by non-basic chalcone analogues."

No. Sentence Comment

378 Functional analysis of the human variants of breast cancer resistance protein: I206L, N590Y, and D620N. Login to comment

PMID: 18668433 [PubMed] Koshiba S et al: "Human ABC transporters ABCG2 (BCRP) and ABCG4."

No. Sentence Comment

225 Based on the currently available data on SNPs and acquired mutations, a total of 18 variant forms of ABCG2 (V12M, G51C, Q126stop, Q141K, T153M, Q166E, I206L, F208S, S248P, E334stop, F431L, S441N, R482G, R482T, F489L, F571I, N590Y, and D620N) were created by site-directed mutagenesis and expressed in Sf9 insect cells (Tamura et al. 2006, 2007). Login to comment

PMID: 18824523 [PubMed] Merino G et al: "Natural allelic variants of bovine ATP-binding cassette transporter ABCG2: increased activity of the Ser581 variant and development of tools for the discovery of new ABCG2 inhibitors."

No. Sentence Comment

218 Vethanayagam RR, Wang H, Gupta A, Zhang Y, Lewis F, Unadkat JD, and Mao Q (2005) Functional analysis of the human variants of breast cancer resistance protein: I206L, N590Y, and D620N. Login to comment

PMID: 18855611 [PubMed] Zhou SF et al: "Clinical pharmacogenetics and potential application in personalized medicine."

No. Sentence Comment

628 Several other variants such as I206L, N520Y and D620N are much less frequent with allele frequencies of ~1%. Login to comment
647 On the other hand, the V12M (and D620N) ABCG2 displayed a comparable ATPase activity as the wild-type protein. Login to comment

PMID: 19002564 [PubMed] Polgar O et al: "The 315-316 deletion determines the BXP-21 antibody epitope but has no effect on the function of wild type ABCG2 or the Q141K variant."

No. Sentence Comment

62 We have previously used the same expression system to study non-synonymous SNPs, such as Q141K, V12M, and D620N, and found that Q141K results in impaired function [13]. Login to comment
64 We have previously used the same expression system to study non-synonymous SNPs, such as Q141K, V12M, and D620N, and found that Q141K results in impaired function [13]. Login to comment

PMID: 19111841 [PubMed] Noguchi K et al: "Functions of the breast cancer resistance protein (BCRP/ABCG2) in chemotherapy."

No. Sentence Comment

874 Among these SNPs, with the exception of C376T and C421A, only a few have been studied Table 1 Identified SNPs within the BCRP gene Variation Effect Domain A-1379G - Δ-654/-651 - G-286C - T-476C - Δ-235A - A-113G - A-29G - G34A V12M N-terminal T114C No change N-terminal G151T G51C N-terminal C369T No change NBD C376T Q126stop NBD C421A Q141K NBD C458T T153M NBD C474T No change NBD C496G Q166E NBD A564G No change NBD A616C I206L NBD T623C F208S NBD T742C S248P Linker G1000T E334stop Linker G1098A No change Linker T1291C F431L TMD A1425G No change TMD T1465C F489L TMD A1768T N590Y TMD G1858A D620N TMD G2237T - G2393T - NBD, nucleotide-binding domain; TMD, transmembrane domain. Login to comment

PMID: 19139722 [PubMed] Nakamichi N et al: "Synergistic effect of interleukin-6 and endoplasmic reticulum stress inducers on the high level of ABCG2 expression in plasma cells."

No. Sentence Comment

281 Functional analysis of the human variants of breast cancer resistance protein: I206 L, N590Y, and D620N. Login to comment

PMID: 19827267 [PubMed] Ishikawa T et al: "Human ABC transporter ABCG2 in cancer chemotherapy and pharmacogenomics."

No. Sentence Comment

222 COOH H2N N590Y V12M G51C Q126stop Q141K T153M Q166E I206L F208S S248P E334stop F431L F489L D620N R482G R482T S441N F571I OUT IN R160Q R575stop ATP-binding site Figure 7. Continued A 005-024 pp JETO-0900616-TI (Review).indd 8/7/2009 3:59:50 19 Q141K has been associated with lower levels of protein expression and impaired transport in vitro (Imai et al., 2002; Kobayashi et al., 2005; Misuarai et al., 2004; Zamber et al., 2003; Morisaki et al., 2008; Kondo et al., 2004). Login to comment
232 It is known that, in the ER, the N-linked glycans play pivotal roles in protein fold- 0.0 0.5 1.0 1.5 Mock WT V12M G51C Q126stop Q141K T153M Q166E I206L F208S S248P E334stop F431L S441N F489L F571I N590Y D620N R482G R482T Methotrexatetransport (nmol/min/mgprotein) Methotrexate 0.0 0.5 1.0 1.5 0.0 0.5 1.0 1.5 Mock WT V12M G51C Q126stop Q141K T153M Q166E I206L F208S S248P E334stop F431L S441N F489L F571I N590Y D620N R482G R482T Methotrexatetransport (nmol/min/mgprotein) MethotrexateMethotrexate Porphyrintransport (nmol/min/mgprotein) 0.0 0.1 0.2 0.3 0.4 0.5 0.0 0.1 0.2 0.3 0.4 0.5 Porphyrin Figure 7. Login to comment

PMID: 19949923 [PubMed] Aszalos A et al: "Flow cytometric evaluation of multidrug resistance proteins."

No. Sentence Comment

260 Three other variants, I206L, N590Y, and D620N, were studied by Vethanayagam et al. Login to comment

PMID: 19949928 [PubMed] Ross DD et al: "Impact of breast cancer resistance protein on cancer treatment outcomes."

No. Sentence Comment

87 found the I206L allele to have high transporter activity but low protein expression when transfected into human embryonic kidney (HEK) cells, whereas the N590L and D620N had higher expression but lower activity (85). Login to comment

PMID: 21103975 [PubMed] Meyer zu Schwabedissen HE et al: "In vitro and in vivo evidence for the importance of breast cancer resistance protein transporters (BCRP/MXR/ABCP/ABCG2)."

No. Sentence Comment

252 There is profound variability in the minor allele frequencies (AF) of those polymorphisms among populations of different ethnicities, and some of the polymorphisms have been described in single individuals only, such as the c.616A>C, p.I206L (Zamber et al. 2003), the c.2062G>A (p.D620N) (Honjo et al. 2002), and the frameshift mutation c.1515delC (p.AFFVM505-509 ASSLstop) (Itoda et al. 2003). Login to comment

PMID: 21188243 [PubMed] Ishikawa T et al: "Key Role of Human ABC Transporter ABCG2 in Photodynamic Therapy and Photodynamic Diagnosis."

No. Sentence Comment

167 Based on the currently available data on SNPs and acquired mutations, we have created a total of 18 variant forms of ABCG2 (V12M, G51C, Q126stop, Q141K, T153M, Q166E, I206L, F208S, S248P, E334stop, F431L, S441N, R482G, R482T, F489L, F571I, N590Y, and D620N) by site-directed mutagenesis and expressed them in insect cells [41, 90]. Login to comment
177 Gefitinib and imatinib are new anticancer drugs Outside Plasma membrane Inside H2N COOH V12M G51C Q126stop Q141K T153M R160Q Q166E I206L F208S S248P E334stop F431L F489L S441N R482G R482T F571I R575stop N590Y D620N T542A A528T D296H P269S ATP-binding cassette (a) 0 0.1 0.3 0.4 0.2 0.5 Mock WT V12M G51C Q126stop Q141K T153M Q166E I206L F208S S248P E334stop F431L S441N F489L F571I N590Y D620N R482G R482T ATP-dependenthematoporphyrin transport(nmol/min/mgprotein) (b) Figure 4: (a) Schematic illustration of human ABCG2 and its nonsynonymous polymorphisms. Login to comment

PMID: 20103563 [PubMed] Klaassen CD et al: "Xenobiotic, bile acid, and cholesterol transporters: function and regulation."

No. Sentence Comment

6589 Absent C421A Q141K 2 Normal/reduced G445C A149P ↔ Normal G448A R163K ↔ Normal C496G Q166E ↔ Normal/reduced A616C I206L 2↔ Normal T623C F208S N.D. Reduced T742C S248P N.D. Normal C805T P269S 2↔ Normal T1291C F431L 2 Normal/reduced G1322A S441N 2 Reduced T1465C F489L 2↔ Normal/reduced A1768T N590Y 2↔ Increased G1858A D620N 2↔ Normal 2, reduced function; ↔, no change in function; N.D. not determined. Login to comment

PMID: 16815813 [PubMed] Choudhuri S et al: "Structure, function, expression, genomic organization, and single nucleotide polymorphisms of human ABCB1 (MDR1), ABCC (MRP), and ABCG2 (BCRP) efflux transporters."

No. Sentence Comment

583 SNP analyses of the ABCG2 gene by Morisaki et al. (2005) revealed three nonsynonymous SNPs that resulted in amino acid substitution of the BCRP protein; these were Val12Met, Gln141Lys, and Asp620Asn. Login to comment

PMID: 21821808 [PubMed] Real R et al: "Analysis of the effect of the bovine adenosine triphosphate-binding cassette transporter G2 single nucleotide polymorphism Y581S on transcellular transport of veterinary drugs using new cell culture models."

No. Sentence Comment

480 Functional analysis of the human variants of breast cancer resistance protein: I206L, N590Y, and D620N. Login to comment

PMID: 25036722 [PubMed] Szafraniec MJ et al: "Determinants of the activity and substrate recognition of breast cancer resistance protein (ABCG2)."

No. Sentence Comment

201 To elucidate the significance of this polymorphism for porphyrin transport, a set of 18 variants of BCRP (Val12 Met, Gly51 Cys, Gln126 stop, Gln141 Lys, Thr153 Met, Gln166 Glu, Ile206 Leu, Phe208 Ser, Ser248 Pro, Glu334 stop, Phe431 Leu, Ser441 Asn, Arg482 Gly, Arg482 Thr, Phe489 Leu, Phe571 Ile, Asn590 Tyr and Asp620 Asn) have been expressed in insect cells. Login to comment
212 The naturally occurring mutations, Asn590 Tyr and Asp620 Asn, predicted to be localized in the extracellular region linking the TM5 and the TM6 domains (Wang et al., 2009), were also analyzed in HEK-293 cells transfected with BCRP bearing these substitutions. Login to comment
214 The efflux ability of Asp620 Asn-BCRP was also reduced, but not as much as in Asn590 Tyr BCRP. Login to comment

PMID: 25236865 [PubMed] Mao Q et al: "Role of the breast cancer resistance protein (BCRP/ABCG2) in drug transport--an update."

No. Sentence Comment

218 V12M resulting from the 34G>A SNP and other variants (e.g., I206L, F208S, N590Y, and D620N) display expression levels and drug resistance profiles comparable to wild-type BCRP (100,101). Login to comment