ABCB1 p.Asn21Val
| Predicted by SNAP2: | A: N (72%), C: D (63%), D: N (61%), E: N (87%), F: N (66%), G: N (78%), H: N (78%), I: N (72%), K: N (87%), L: N (72%), M: N (82%), P: D (63%), Q: N (87%), R: N (82%), S: N (78%), T: N (87%), V: N (72%), W: N (57%), Y: N (57%), |
| Predicted by PROVEAN: | A: N, C: N, D: N, E: N, F: N, G: N, H: N, I: N, K: N, L: N, M: N, P: N, Q: N, R: N, S: N, T: N, V: N, W: N, Y: N, |
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[hide] Targeting mammalian target of rapamycin to both do... Leuk Lymphoma. 2009 Jul;50(7):1155-62. Pop IV, Pop LM, Ghetie MA, Vitetta ES
Targeting mammalian target of rapamycin to both downregulate and disable the P-glycoprotein pump in multidrug-resistant B-cell lymphoma cell lines.
Leuk Lymphoma. 2009 Jul;50(7):1155-62., [PMID:19557637]
Abstract [show]
Previous studies have shown that rapamycin can inhibit the growth of several different types of human tumor cells in vitro. In certain cases, it can reverse the phenotype of multidrug resistant (MDR) cells. However, there is limited information concerning its effect on P-glycoprotein (P-gp), a pump that is responsible for chemoresistance in many MDR cells. We investigated the effect of rapamycin on both P-gp function and the MDR phenotype in four cell lines. One cell line was also xenografted into SCID mice to determine whether rapamycin would chemosensitize the cells in vivo. Because rapamycin targets the mammalian target of rapamycin (mTOR) pathway, we also used our cells to confirm that rapamycin modified the expression of mTOR and effectively suppressed the phosphorylation of two downstream effector molecules in the mTOR pathway, S6K1, and 4E-BP1. We demonstrated that it inhibited the growth of the three cell lines in vitro and one in vivo showing that it modulated both the expression and function of P-gp and chemosensitized the three cell lines as effectively as verapamil.
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No. Sentence Comment
28 Materials and methods Cell lines The following MDR cell lines were used: two Burkitt lymphoma cell lines Namalwa 21 nM Vincristine (VCR) (N21V), and Raji 18 nM VCR (R18V), and the diffuse hystiocytic lymphoma, DHL-4/12 nM VCR (D12V), as well as the standard MDR cells, Namalwa/MDR1, which were a gift from Dr. R. O`Connor at ImmunoGen (Boston, MA).
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ABCB1 p.Asn21Val 19557637:28:138
status: NEW30 The MDR variants of Raji, DHL-4, and Namalwa, were generated by drug-selection in our laboratory and were named by the parental cells name and the final concentration of VCR to which they were resistant (e.g., N21V, R18V, and DHL-4/ 12V) [7].
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ABCB1 p.Asn21Val 19557637:30:210
status: NEW70 Equal amounts of protein from each cells lysate were loaded and gels were scanned and analyzed quantitatively to compare the amount of P-gp expressed by each MDR cell line: Namalwa/MDR1; Namalwa 21 nM VCR (N21V); Raji 18 nM VCR (R18V); and DHL-4/12 nM VCR (DHL-4/12V).
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ABCB1 p.Asn21Val 19557637:70:206
status: NEW77 As shown in the figure, Namalwa/MDR1 and N21V cells reached their peak of growth inhibition after 48 h of incubation in the presence of 0.55 mM rapamycin, whereas R18V continued to be inhibited for up to 72 h, and DHL-4/12V was inhibited up to 96 h.
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ABCB1 p.Asn21Val 19557637:77:41
status: NEW82 The cells express variable amounts of P-gp: Namalwa/MDR1 4 R18V 4 D12V 4 N21V.
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ABCB1 p.Asn21Val 19557637:82:73
status: NEW93 As shown in the top line of Figure 1, and in Figure 5, the expression of P-gp is down-regulated in rapamycin-treated Namalwa/MDR1 and N21V cells.
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ABCB1 p.Asn21Val 19557637:93:133
status: NEW94 The effect of rapamycin on the growth of Namalwa 21 nM VCR cells in vivo In these experiments, N21V cells were injected intravenously into SCID mice.
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ABCB1 p.Asn21Val 19557637:94:95
status: NEW101 ); Namalwa 21 nM VCR (N21V) (); Raji 18 nM VCR (R18V) (!
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ABCB1 p.Asn21Val 19557637:101:22
status: NEW114 As expected, the SCID mice with N21V tumors did not respond to treatment with VCR but did respond to rapamycin.
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ABCB1 p.Asn21Val 19557637:114:32
status: NEW118 Discussion We have previously described the generation of three drug-resistant lymphoma cell lines (N21V, R18V, and DHL-4/12V) by drug-selection and these cells expressed P-gp and effluxed rhodamine, suggesting that the P-gp pump was active [7].
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ABCB1 p.Asn21Val 19557637:118:100
status: NEW157 Namalwa/MDR1 and N21V cells treated as shown in the legend of Figure 1 were analyzed by FACS for P-gp expression after 48 h incubation at 378C using a UIC2-shift assay.
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ABCB1 p.Asn21Val 19557637:157:17
status: NEW160 The graph shows the results obtained using Namalwa/MDR1 and Namalwa 21 nM VCR (N21V) cells.
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ABCB1 p.Asn21Val 19557637:160:79
status: NEW163 Survival of SCID mice xenografted with the MDR tumor N21V cells and treated with rapamycin + VCR.
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ABCB1 p.Asn21Val 19557637:163:53
status: NEW[hide] Generation of multidrug resistant lymphoma cell li... Oncol Rep. 2008 Apr;19(4):889-95. Pop I, Pop L, Vitetta ES, Ghetie MA
Generation of multidrug resistant lymphoma cell lines stably expressing P-glycoprotein.
Oncol Rep. 2008 Apr;19(4):889-95., [PMID:18357372]
Abstract [show]
The objective of this study was to generate new P-glycoprotein (P-gp)-expressing multidrug resistant (MDR) cell lines by drug selection. Since our previous studies have been carried out with cells infected with a P-gp-containing vector, it was important to confirm our findings in cells generated by drug selection. In this report, we describe three B-lymphoma cell lines which became drug-resistant by stepwise exposure to vincristine (VCR): Raji cells resistant to 18 nM VCR (R18V), Namalwa cells resistant to 21 nM VCR (N21V) and DHL-4 cells resistant to 12 nM VCR (DHL-4/12V). Cells overexpressed P-gp and continued to express CD19, CD20 and CD22, all of which are targets for monoclonal antibody (MAb) therapy. The P-gp pump in these new cells was functional as determined by the efflux of Rhodamine 123 and DIOC2, and the three cell lines were resistant to several chemotherapeutic drugs. We further determined that their P-gp phenotype was stable in xenografted SCID mice and that the tumors were also resistant to chemotherapy. We will now use these new MDR cells to determine whether monoclonal antibodies against CD19 and -20 can reverse P-gp, as we previously demonstrated using Namalwa cells infected with a human mdr1 gene-containing retrovirus.
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No. Sentence Comment
29 The cells were named by the parental cell names and the final concentration of VCR to which they were resistant (e.g. N21V, R18V and DHL-4/12V).
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ABCB1 p.Asn21Val 18357372:29:118
status: NEW81 However, 80-90% of drug-selected cells (N21V, R18V and DHL-4/12V) were P-gp+ and the expression of P-gp remained unchanged when the cells were grown in complete RPMI media without VCR.
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ABCB1 p.Asn21Val 18357372:81:40
status: NEW102 As shown in Fig. 4, Namalwa/ MDR1 and N21V cells expressed comparable amounts of P-gp, whereas the R18V cells expressed more P-gp and the DHL-4/12V less than Namalwa/MDR1 for the same amount of protein loaded, which is consistent with the FACS analysis (Table II).
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ABCB1 p.Asn21Val 18357372:102:38
status: NEW109 The phenotype of MDR vs. parental cells.a ------------------------------------------------- Percent of positive cells Cell line CD19 CD20 CD22 P-gp ------------------------------------------------- Namalwa 95.7 83.5 95.5 7.1 NMDR1 92.7 90.9 91.7 90.0 N21V 93.3 90.4 93.3 91.9 Raji 92.0 98.1 91.9 1.8 R18V 92.0 97.3 94.3 85.7 DHL-4 77.8 99.7 76.4 4.1 DHL-4/12V 89.6 98.8 89.6 76.3 ------------------------------------------------- a FACS analysis was performed using saturating concentrations of HD37 and RFB4 and a FITC-GAMIg as a secondary antibody.
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ABCB1 p.Asn21Val 18357372:109:251
status: NEW113 N21V, R18V and Namalwa/MDR1 cells were inoculated into SCID mice and the tumor take was 100%.
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ABCB1 p.Asn21Val 18357372:113:0
status: NEW121 We chose to generate: i) N21V cells, as an alternative to Namalwa/MDR1 cells; ii) R18V cells since Raji cells express more CD20 than Namalwa cells; and iii) DHL-4/12V cells, which are derived from diffuse hystiocytic lymphoma cells, whereas the others are Burkitt's lymphomas.
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ABCB1 p.Asn21Val 18357372:121:25
status: NEW142 (A) Namalwa (ߦ), Namalwa/MDR1 (ߥ) and Namalwa 21 nM VCR (N21V) (t); (B) Raji (n) and Raji 12 nM VCR (R12V) (Þb;).
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ABCB1 p.Asn21Val 18357372:142:69
status: NEW158 The top histograms show the Namalwa 21 nM VCR (N21V) cells and the bottom histograms the Raji 18 nM VCR (R18V).
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ABCB1 p.Asn21Val 18357372:158:47
status: NEW164 The N21V and Namalwa/MDR1 cells contain a comparable amount of P-gp whereas R18V contain more and the DHL-4/12V cells contain less P-gp than the Namalwa/MDR1.
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ABCB1 p.Asn21Val 18357372:164:4
status: NEW175 WB analysis of P-gp overexpression in the new MDR cells (N21V, R18V and DHL-4/12V) and Namalwa/MDR1 vs. P-gp- parental cells.
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ABCB1 p.Asn21Val 18357372:175:57
status: NEW176 Equal amounts of protein from each cell lysate were loaded and the gels were scanned and analyzed quantitatively to compare the amount of P-gp expressed by each MDR cell line: (1) Namalwa, (2) Namalwa/MDR1, (3) Namalwa 21 nM VCR (N21V), (4) Raji, (5) Raji 18 nM VCR (R18V), (6) DHL-4 and (7) DHL-4/12 nM VCR (DHL-4/12V).
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ABCB1 p.Asn21Val 18357372:176:230
status: NEW178 Survival of SCID mice xenografted with parental tumors (Namalwa and Raji) or MDR tumors (Namalwa/MDR1, N21V and R18V) before and after treatment with VCR.
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ABCB1 p.Asn21Val 18357372:178:103
status: NEW183 (A) shows the survival of SCID mice xenografted with Namalwa cells &#b1; VCR (ߦ, control and ߥ, VCR); Namalwa/MDR1 &#b1; VCR (t, control and Ɗ, VCR) and N21V &#b1; VCR (ߦ, control and ߥ, VCR).
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ABCB1 p.Asn21Val 18357372:183:170
status: NEW