ABCMdb

PMID: 19557637

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., [PubMed]

Sentences

No. Mutations Sentence Comment

28 ABCB1 p.Asn21Val 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). Login to comment 30 ABCB1 p.Asn21Val 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]. Login to comment 70 ABCB1 p.Asn21Val 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). Login to comment 77 ABCB1 p.Asn21Val 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. Login to comment 82 ABCB1 p.Asn21Val The cells express variable amounts of P-gp: Namalwa/MDR1 4 R18V 4 D12V 4 N21V. Login to comment 93 ABCB1 p.Asn21Val ABCB1 p.Asn21Val 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. Login to comment 94 ABCB1 p.Asn21Val 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. Login to comment 101 ABCB1 p.Asn21Val ); Namalwa 21 nM VCR (N21V) (); Raji 18 nM VCR (R18V) (! Login to comment 114 ABCB1 p.Asn21Val As expected, the SCID mice with N21V tumors did not respond to treatment with VCR but did respond to rapamycin. Login to comment 118 ABCB1 p.Asn21Val 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]. Login to comment 157 ABCB1 p.Asn21Val 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. Login to comment 160 ABCB1 p.Asn21Val The graph shows the results obtained using Namalwa/MDR1 and Namalwa 21 nM VCR (N21V) cells. Login to comment 163 ABCB1 p.Asn21Val Survival of SCID mice xenografted with the MDR tumor N21V cells and treated with rapamycin + VCR. Login to comment