Background/aim: Naringin, a naturally occurring flavanone glycoside, can inhibit oxidative stress and inflammatory reactions. Atorvastatin, which belongs to the class of drugs called statins, is an inhibitor of 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase and it has shown anticancer activity in prostate cancer (PCa). The present study investigated whether the combination of atorvastatin and naringin has an effect on inhibiting growth in PCa and the mechanisms underlying this effect. Methods: Cell growth was assessed by CCK-8 and trypan blue exclusion assay, and the IC50 of LNCaP and PC-3 cells were determined by MTT assay. Scratch migration and matrigel-coated transwell invasion were used to assess both migration and invasion in prostate cancer cell lines. The expression levels of p-Akt, p-STAT3, survivin, AR, Bcl-2, and Bax in prostate cancer cell lines were determined by Western blot. PC-3 and LNCaP xenografts were applied to assess the effect in vivo. Results: Naringin in combination with atorvastatin had a synergistic inhibitory effect on growth in the prostate cancer cell lines PC-3 and LNCaP, and the combination more strongly inhibited migration and invasion than either single drug. The combination of atorvastatin with naringin potently inhibited the expression levels of AR, p-Akt, survivin, p-STAT3, and Bcl-2. However, an increase in the level of p-STAT3 was found in the PC-3 cells treated with atorvastatin and naringin alone, which differed from that observed in LNCaP. Moreover, the level of Bax in the prostate cancer cell lines treated with atorvastatin and naringin was higher than in those treated with either drug alone. Atorvastatin or naringin treatment had an inhibitory effect on the growth of PC-3 and LNCaP tumors in vivo, and this was especially true of the combined treatment. Conclusions: The data suggest that the combination of atorvastatin and naringin may be an effective method for inhibiting the growth of prostate cancer. Further research is needed to determine the mechanism of action of the combination of atorvastatin and naringin.

Atorvastatin is the most prescribed cholesterol-lowering statin, while caffeine enhances chemo-sensitivity and induces apoptosis of tumor cells through its DNA repair-inhibiting effect. The present study investigated the effects and mechanisms of atorvastatin and caffeine in combination on human prostate cancer cells cultured in vitro . Cell growth were determined by the trypan blue exclusion assay. The cell apoptosis and colony formation were determined by morphological assessment. The ability of cell migration and invasion were performed using a scratch wound-healing and Transwell assay. Tumorspheres were formed in suspension under the condition of non-adherence and serum-free medium. Finally, the western blot assay was used to determine the levels of proteins. The combination synergistically suppressed proliferation and induced apoptotic death. Meanwhile, the migration, invasion, and the formation of tumorspheres were significantly inhibited by the combination. We found that atorvastatin and caffeine in combination downregulated phospho-Akt, phospho-Erk1/2, anti-apoptotic Bcl-2 and Survivin protein levels. Results of the present study indicate treatment with the combination of caffeine and atorvastatin may be an effective strategy for inhibiting the growth of prostate cancer and should be evaluated clinically.

Background: Docetaxel is the first-line treatment for castration-resistant prostate cancer (CRPC). The limited survival benefit associated with the quick emergence of resistance and systemic toxicity diminishes its efficacy in high-dose monotherapy. YK-4-279 is a small molecule inhibitor of ETV1 that plays an important role in the progression of prostate cancer. The aim of this study was to evaluate the hypothesis that the combination of docetaxel and YK-4-279 will have a synergistic effect on inhibiting growth and accelerating apoptosis in human prostate cancer cells. Methods: Cell growth assessed using CCK-8 and trypan blue exclusion assays. Cell apoptosis was determined by morphological assessment in cells stained with propidium iodide. Standard scratch migration and Matrigel-coated transwell invasion assays were used to assess cell migration and invasion, respectively. Western blotting was used to investigate the levels of ETV1, AR, PSA, p-STAT3, survivin, Bcl-2, and p-Akt in prostate cancer cells. Results: The combination of low-dose docetaxel and YK-4-279 synergistically inhibited growth and induced apoptosis in human prostate cancer cells. The combination also more efficiently suppressed the migration and invasion of LNCaP and PC-3 cells. The combination of low-dose docetaxel and YK-4-279 caused a stronger decrease in the levels of ETV1, AR, PSA, p-STAT3, survivin, Bcl-2, and p-Akt in LNCaP cells and of p-Akt, Bcl-2, and p-STAT3 in PC-3 cells compared with either drug alone. Conclusions: These data suggest that the combination of docetaxel and YK-4-279 may be an effective approach for inhibiting the growth and metastasis of prostate cancer. This could permit a decrease in the docetaxel dose necessary for patients with CRPC and thereby lower its systemic toxicity.

Docetaxel is a commonly used chemotherapeutic drug for patients with late stage prostate cancer. However, serious side effect and drug resistance limit its clinical success. Brefeldin A is a 16-membered macrolide antibiotic from mangrove-derived Fungus Aspergillus sp. (9Hu), which exhibited potent cytotoxicity against human cancer cells. In the present study, we determined the effect of brefeldin A on docetaxel-induced growth inhibition and apoptosis in human prostate cancer PC-3 cells. Brefeldin A in combination with docetaxel inhibited the growth of PC-3 cells in monolayer and in three dimensional cultures. The combination also potently stimulated apoptosis in PC-3 cells as determined by propidium iodide staining and morphological assessment. Mechanistic studies showed that growth inhibition and apoptosis in PC-3 cells treated with brefeldin A and docetaxel were associated with decrease in the level of Bcl-2. The present study indicates that combined brefeldin A with docetaxel may represent a novel approach for improving the efficacy of docetaxel, and Bcl-2 may serve as a target for brefeldin A to enhance the effects of docetaxel chemotherapy.