The Effects of Matrine in Combination with Docetaxel on Castration-Resistant (Androgen-Independent) Prostate Cancer

Matrine (MAT) exhibits higher efficacy of chemotherapy when it is combined with other chemotherapeutic drugs; however, the therapeutic efficacy of matrine in combination with docetaxel (DOC) for prostate cancer, or even androgen-independent prostate cancer, remains poorly understood and the underlying molecular mechanisms have not yet been clearly defined. In the present study, we investigated whether matrine combined with docetaxel can strengthen anti-cancer effect.

In this study, 7 groups were established, including (1) blank control group (cells). (2) 0.1 g/L MAT group, (3) 0.5 g/L MAT group, (4) 0.1 g/L MAT+ 50 μg/L DOC group, (5) 0.5 g/L MAT+ 50 μg/L DOC group, (6) 0.1 g/L MAT+ 100 μg/L DOC group, and (7) 0.5 g/L MAT+ 100 μg/L DOC group. MTS assay was performed to detect the anti-proliferative effects of each group on DU145 and PC-3 cells. At the same time, Transwell assay was performed to detect anti-migrative and anti-invasive effects of each group on DU145 and PC-3 cells. Biochemical colorimetric method and enzyme-linked immunosorbent assay were performed to detect the levels of LDH, IL-1β and IL-18 of each group on DU145 and PC-3 cells. Flow cytometry (FCM) assay was used to do the apoptosis analysis on DU145 and PC-3 cells of each group. At last, Western blot analysis was performed to investigate the expression levels of caspase1 in cells of each group. Statistical analyses were performed with SPSS 17.0 (SPSS Inc, USA) software, and one-way ANOVA and Fisher's exact test was taken.

MTS assay showed that matrine combined with docetaxel could inhibit both DU145 and PC-3 cells' proliferation in a dose- and time-dependent manner. Transwell assay showed that matrine combined with docetaxel could inhibit both DU145 and PC-3 cells' migration and invasion in a dose- and time-dependent manner. The levels of LDH, IL-1β and IL-18 of matrine combined with docetaxel-treated DU145 and PC-3 cells were significantly increased, compared with the untreated control cells. Flow cytometry, as well as Annexin-V/PI staining, showed a significant and dose-dependent increase in the number of early, as well as late-stage apoptotic cells in both DU145 and PC-3 cells compared with the untreated control cells. Western blot analysis showed that matrine combined with docetaxel treatment led to the expression of caspase1 in both DU145 and PC-3 cells.

It may be more effective to use matrine in combination with docetaxel to treat androgen-resistant prostate cancer because matrine can help to affect proliferation, migration, invasion, apoptosis, metabolism, and have anti-inflammation effect on the tumor cells.