Information
Tariquidar (XR9576) Tariquidar (XR9576) is a potent and selective noncompetitive inhibitor of P-glycoprotein with K d of 5.1 nM in CHrB30 cell line, reverses drug resistance in MDR cell Lines. Phase 3.
In vitro
Tariquidar displays high-affinity binding to P-gp with Bmax of 275 pmol/mg. Tariquidar shows non-competitive interaction with the P-gp substrates vinblastine and paclitaxel. Tariquidar increases the steady-state accumulation of these cytotoxics in CHrB30 cells to levels observed in non-P-gp-expressing AuxB1 cells with EC50 of 487 nM. Tariquidar is able to inhibit the vanadate-sensitive ATPase activity of P-gp by 60-70%, with potent IC50 values of 43 nM. Tariquidar may inhibit other resistance mechanisms at higher concentrations. 1 μM Tariquidar abrogates ABCG2 (BCRP)-mediated resistance to camptothecins in vitro. Tariquidar potentiates the cyto-toxicity of several drugs including doxorubicin, paclitaxel, etoposide, and vincristine; complete reversal of resistance is achieved in the presence of 25- 80 nM Tariquidar. In MC26, a murine colon carcinoma cell line with intrinsic chemoresistance, the doxorubicin IC50 is fivefold lower in the presence of 0.1 μM Tariquidar (36 vs 7 nM). In murine mammary carcinoma, human small-cell lung carcinoma and human ovarian carcinoma cell lines with acquired chemotherapeutic resistance (EMT6/AR1.0, H69/LX4 and 2780 AD), the in vitro doxorubicin IC50 is 22-150-fold lower in the presence of 0.1 μM Tariquidar. P-gp inhibition persists for 23 h after removal of Tariquidar from the culture system. Tariquidar restored the cyto-toxicity of doxorubicin and vinblastine in the National Cancer Institute (NCI)/ADRRES multicellular tumor spheroid model derived from the MCF7WT breast cancer cell line.
In vivo
Tariquidar (2- 8 mg/kg p.o.) is found to significantly potentiate the antitumor activity of doxorubicin (5 mg/kg, i.v.) against MC26 murine colon carcinoma in vivo. In human carcinoma xenografts, coadministration of XR9576 (6 -12 mg/kg p.o.) fully restored the antitumor activity of paclitaxel, etoposide, and vincristine against two highly resistant MDR human tumor xenografts (2780AD, H69/LX4) in nude mice.
Cell Data
cell lines：
Concentrations：~100 nM Tariquidar
Incubation Time：4 days
Powder Purity:≥99%
