Alteration of Androgen Receptor Protein Stability by Triptolide in LNCaP Cells.

Background and Objective: Although triptolide was effective for prostate cancer (PCa), the mechanism is still unclear. Androgen receptor (AR) plays a large role in the development and progression of PCa, even after castration. The present study aimed at investigating the effects of triptolide on AR protein stability and the possible mechanism. Materials and Methods: By blocking protein synthesis with cycloheximide (CHX), the effect of triptolide on AR protein stability was investigated with western blot assay. The potential role of calpains in triptolide reduced AR protein stability was investigated with calpain inhibitor and Ca2+ chelator. Results: Triptolide down-regulated AR protein level when protein synthesis was blocked by CHX, demonstrating the decrease of AR protein stability. The AR protein level was restored when the cells were co-treated with triptolide and calpain inhibitor or Ca2+ chelator, indicating the important role of calpains. Conclusions: The results indicate that triptolide can activate calpain via promoting intracellular Ca2+ accumulation, and thus decrease the stability of AR protein, subsequently resulting in the breakdown of the AR protein in LNCaP cells. This work provides an experimental basis and evidence to elucidate the anti-PCa mechanisms of triptolide.

Effect of prostate volume on the peripheral nerve block anesthesia in the prostate biopsy: A strobe-compliant study.

OBJECTIVE: The objective of this study was to evaluate the anesthetic efficacy of periprostatic nerve block (PNB) in transrectal ultrasound (TRUS)-guided biopsy on different prostate volume. METHODS: A total of 568 patients received prostate biopsy in our hospital from May 2013 to September 2015 and were retrospectively studied. All patients were divided into local anesthesia group (LAG) and nerve block group (NBG). Then each group was subdivided into 4 subgroups (20-40, 40-60, 60-100, and >100 mL groups) according to different prostate volume range. Visual analogue scale (VAS) and visual numeric scale (VNS) were used to assess the patient's pain and quantify their satisfaction. The scores and complications were compared between the groups. RESULTS: The age and serum prostate-specific antigen (PSA) level before biopsy had no significant differences at intergroup or intragroup level. The VAS scores were significantly lower in the NBG than those in the LAG in terms of prostate volume (1 (1-2) versus 2 (1-3), 2 (1-3) versus 2 (2-4), 2 (2-3) versus 3 (2-5), 4 (3-5) versus 5 (4-7), all P < 0.05). Conversely, the VNS scores were higher in the NBG (4 (3-4) versus 3.5 (3-4), 3 (3-4) versus 3 (3-3), 3 (2-4) versus 3 (2-3), 2 (2-2) versus 1 (1-2), all P < 0.05). Patients with smaller prostate volume undergoing PNB or local anesthesia experienced significantly lower pain and higher satisfaction scores than those with large prostate. Whether in PNB or local anesthesia group, patients with large prostate volume had more chance to have hematuria, hemospermia, urinary retention than smaller one except infection (P < 0.05). Those complications had no significant differences between LAG and NBG (P > 0.05). CONCLUSION: Compared with local anesthesia, ultrasound-guided PNB has superior analgesic effect and equal safety, but for patients with a large prostate volume, the analgesic effect is inefficient.

[Effects of triptolide on the expression of androgen receptor in human prostate LNCaP cells and its mechanism of action].

To study the regulation of androgen receptor (AR) expression in human prostate cancer LNCaP cells by triptolide (TP) and the possible mechanism, by using qRT-PCR and Western blot, the AR mRNA and protein levels in TP treated LNCaP cells were detected, and the AR protein level in TP and NF-κB inhibitor treated LNCaP cells was also detected; a series of pGL3-AR promoter reporter gene vectors were built using restriction-free cloning method, and the vectors were employed to investigate the effects of TP on the transcriptional activity of AR promoter in LNCaP cells; the upstream proteins which may play regulatory roles were detected using western blot assay. After treated LNCaP cells with TP for 48 h, AR mRNA and protein expressions decreased with increasing TP concentration. The expression of AR target gene PART1 and prostate specific antigen (PSA) was also downregulated by TP treatment; a series of pGL3-AR promoter reporter vectors were constructed and validated by sequencing and luciferase activity; the results of dual luciferase reporter assay showed that TP downregulated AR at the transcriptional level; PI3K/AKT/NF-κB pathway which is associated with AR promoter activity was drowregulated by TP. In conclusion, our results demonstrated that the transcriptional activity of AR in LNCAP cells was downregulated by TP, and PI3K/AKT/NF-κB pathway may be involved in the regulation mechanism.