HIV-1 protease inhibitor, ritonavir: a potent inhibitor of CYP3A4, enhanced the anticancer effects of docetaxel in androgen-independent prostate cancer cells in vitro and in vivo.

Article Details

Citation

Ikezoe T, Hisatake Y, Takeuchi T, Ohtsuki Y, Yang Y, Said JW, Taguchi H, Koeffler HP

HIV-1 protease inhibitor, ritonavir: a potent inhibitor of CYP3A4, enhanced the anticancer effects of docetaxel in androgen-independent prostate cancer cells in vitro and in vivo.

Cancer Res. 2004 Oct 15;64(20):7426-31.

PubMed ID
15492266 [ View in PubMed
]
Abstract

We previously showed that HIV-1 protease inhibitors (PIs) slowed the proliferation of human myeloid leukemia cells and enhanced their differentiation in the presence of all-trans-retinoic acid. In this study, we found that PIs, including ritonavir, saquinavir, and indinavir, inhibited the growth of DU145 and PC-3 androgen-independent prostate cancer cells as measured by a clonal proliferation assay. Recent studies showed that ritonavir inhibited cytochrome P450 3A4 enzyme (CYP3A4) in liver microsomes. The CYP3A4 is involved in drug metabolism and acquisition of drug resistance. To clarify the drug interaction between ritonavir and other anticancer drugs, we cultured DU145 cells with docetaxel either alone or in combination with ritonavir. Ritonavir enhanced the antiproliferative and proapoptotic effects of docetaxel in the hormonally independent DU145 prostate cancer cells in vitro as measured by the clonogenic soft agar assay and detection of the activated form of caspase-3 and cleavage of poly(ADP-ribose) polymerase using Western blot analysis. Real-time PCR showed that docetaxel induced the expression of CYP3A4 at the transcriptional level, and ritonavir (10(-5) mol/L) completely blocked this induction. An ELISA-based assay also showed that ritonavir inhibited DNA binding activity of nuclear factor kappaB (NFkappaB) in DU145 cells, which is a contributor to drug resistance in cancer cells. Furthermore, combination treatment of docetaxel and ritonavir dramatically inhibited the growth of DU145 cells present as tumor xenografts in BNX nude mice compared with either drug alone. Importantly, docetaxel induced expression of CYP3A4 in DU145 xenografts, and ritonavir completely blocked this induction. Ritonavir also inhibited NFkappaB DNA binding activity in DU145 xenografts. Extensive histologic analyses of the liver, spleen, kidneys, bone marrow, skin, and subcutaneous fat pads from these mice showed no abnormalities. In summary, combination therapy of ritonavir and anticancer drugs holds promise for the treatment of individuals with advanced, drug resistant cancers.

DrugBank Data that Cites this Article

Drug Targets
DrugTargetKindOrganismPharmacological ActionActions
DocetaxelNuclear receptor subfamily 1 group I member 2ProteinHumans
Unknown
Binder
Details
Drug Interactions
DrugsInteraction
Clorazepic acid
Saquinavir
The serum concentration of Clorazepic acid can be increased when it is combined with Saquinavir.
Trazodone
Boceprevir
The serum concentration of Trazodone can be increased when it is combined with Boceprevir.
Trazodone
Cobicistat
The serum concentration of Trazodone can be increased when it is combined with Cobicistat.
Trazodone
Troleandomycin
The serum concentration of Trazodone can be increased when it is combined with Troleandomycin.
Trazodone
Midostaurin
The serum concentration of Trazodone can be increased when it is combined with Midostaurin.