Clinical Evaluation of Abiraterone in the Treatment of Metastatic Prostate Cancer

Effect of SIRT1 Gene on Epithelial-Mesenchymal Transition of Human Prostate Cancer PC-3 Cells

Background

The epithelial-mesenchymal transition (EMT) has been shown to be involved in the process of invasion and metastasis of prostate cancer. SIRT1 is the mammalian homologue of the silent information regulator 2 (Sir2) gene, and is abnormally expressed in prostate cancer cells. Therefore, it is hypothesized that SIRT1 mediates the invasion/metastatic ability of prostate cancer via EMT regulation. This study thus investigated the effect of SIRT1 gene on the invasion and migration of prostate cancer cell line PC-3 via the small interference RNA (siRNA) against SIRT1.

Material/Methods

SiRNA construct was transfected into PC-3 cells, which were tested for the cell migration and invasion ability by scratch assay and Transwell migration assay, respectively. Expression levels of vimentin, E-cadherin, and N-cadherin were further quantified by Western blotting and RT-PCR.

Results

Both mRNA and protein levels of SIRT1 were depressed after siRNA transfection, along with weakened migration and invasion ability of PC-3 cells. Elevated E-cadherin and suppressed N-cadherin and vimentin were observed in those transfected cells.

Conclusions

The silencing of SIRT1 gene in PC-3 cells can suppress the movement, migration, and invasion functions of prostate cancer cells, possibly via the down-regulation of mesenchymal markers vimentin and N-cadherin accompanied with up-regulation of epithelial marker N-cadherin, thus reversing the EMT process.

Comparative analysis of the effectiveness of abiraterone before and after docetaxel in patients with metastatic castration-resistant prostate cancer

AIM: To study the efficacy and safety of abiraterone in patients with and without prior chemotherapy.

METHODS: The databases including PubMed and abstracts presented at the American Society of Clinical Oncology meetings up to April 2014 were systematically searched. Eligible studies included randomized controlled trials (RCTs) in which abiraterone plus prednisone was compared to placebo plus prednisone in metastatic castration-resistant prostate cancer (CRPC) patients. The summary incidence, relative risk, hazard ratio and 95%CI were calculated using random or fixed-effects models. Heterogeneity test was performed to test between-study differences in efficacy and toxicity.

RESULTS: A total of two phase III RCTs were included in our analysis, with metastatic CPRC patients before (n = 1088) and after chemotherapy (n = 1195). Prior chemotherapy did not significantly alter the effect of abiraterone on overall survival (P = 0.92) and prostate-specific antigen (PSA) progression-free survival (P = 0.13), but reduced its effect on radiographic-progression-free survival (P = 0.04), objective response rate (P < 0.001), and PSA response rate (P < 0.001). Prior chemotherapy significantly increased the specific risk of fluid retention and edema (P < 0.001) and hypokalemia (P < 0.001), but decreased the risk of all-grade hypertension (P < 0.001) attributable to abiraterone. There was no significant difference of cardiac disorders associated with abiraterone between the two settings (P = 0.58).

CONCLUSION: Prior chemotherapy may reduce the effectiveness of abiraterone in patients with metastatic CRPC.

Detection and screening of small molecule agents for overcoming Sorafenib resistance of hepatocellular carcinoma: a bioinformatics study

Sorafenib, a novel orally-available multikinase inhibitor blocking several crucial oncogenic signaling pathways, presented survival benefits and became the first-line drug for treatment of patients with Hepatocellular carcinoma (HCC). However, the acquired resistance to Sorafenib resulted in limited benefits. In this study, we aimed to explore possible agents that might overcome Sorafenib resistance by bioinformatics methods. The gene expression profiles of HCC-3sp (acquired Sorafenib-resistance) and HCC-3p (Sorafenib-sensitive) cell line were downloaded from Gene Expression Omnibus (GEO) database. Then, the differentially expressed genes (DEGs) were selected using dChip software. Furthermore, Gene Ontology (GO) and pathway enrichment analyses were performed by DAVID database. Finally, the Connectivity Map was utilized to predict potential chemicals for reversing Sorafenib resistance. Consequently, a total of 541 DEGs were identified, which were associated with cell extracellular matrix, cell adhesion and binding-related items. KEGG pathway analysis indicated that 8 dysfunctional pathways were enriched. Finally, several small molecules, such as pregnenolone and lomustine, were screened out as potential therapeutic agents capable of overcoming Sorafenib resistance. The data identified some potential small molecule drugs for treatment of Sorafenib resistance and offered a novel strategy for investigation and treatments of HCC.

Advanced prostate cancer - patient survival and potential impact of enzalutamide and other emerging therapies

The advent of exponential growth of novel agents tested and approved for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) has brought about a need for understanding of the mechanism of action, side-effects, and clinical efficacy of these drugs as they relate to these patients. This review will provide a synopsis of the treatment landscape in mCRPC as varying agents such as abiraterone acetate, cabazitaxel, sipuleucel-T, radium, and selected emerging agents are presented. A distinct focus on the utilization of enzalutamide, its mechanism of action, key pivotal trials that brought about its US Food and Drug Administration approval, as well as patient-focused perspectives and clinical implications are discussed herein.