Prima-1 induces apoptosis in bladder cancer cell lines by activating p53

OBJECTIVES: Bladder cancer represents 3% of all carcinomas in the Brazilian population and ranks second in incidence among urological tumors, after prostate cancer. The loss of p53 function is the main genetic alteration related to the development of high-grade muscle-invasive disease. Prima-1 is a small molecule that restores tumor suppressor function to mutant p53 and induces cancer cell death in various cancer types. Our aim was to investigate the ability of Prima-1 to induce apoptosis after DNA damage in bladder cancer cell lines. METHOD: The therapeutic effect of Prima-1 was studied in two bladder cancer cell lines: T24, which is characterized by a p53 mutation, and RT4, which is the wild-type for the p53 gene. Morphological features of apoptosis induced by p53, including mitochondrial membrane potential changes and the expression of thirteen genes involved in apoptosis, were assessed by microscopic observation and quantitative real-time PCR (qRT-PCR). RESULTS: Prima-1 was able to reactivate p53 function in the T24 (p53 mt) bladder cancer cell line and promote apoptosis via the induction of Bax and Puma expression, activation of the caspase cascade and disruption of the mitochondrial membrane in a BAK-independent manner. CONCLUSION: Prima-1 is able to restore the transcriptional activity of p53. Experimental studies in vivo may be conducted to test this molecule as a new therapeutic agent for urothelial carcinomas of the bladder, which characteristically harbor p53 mutations.

An evaluation of the anti-neoplastic activity of curcumin in prostate cancer cell lines

OBJECTIVE: The aim of our study is to investigate the anti-neoplastic effect of curcumin in prostate cancer cell lines. Specifically, we are using the LNCaP cell line and another prostate cell line developed in our laboratory, PcBra1. The PcBra1 cells were derived from a localized, obstructive prostate cancer with a Gleason score of 9 (4+5). MATERIAL AND METHODS: A prostate cancer cell line was isolated from a localized, obstructive prostate cancer with a Gleason score of 9 (4+5), and it was characterized using immunohistochemistry. After six passages, the new cell line was treated with varying doses of curcumin: 10 µM, 25 µM or 50 µM. Apoptosis was detected by flow cytometry using Annexin V FITC. For comparison, the same experiment was performed using the well-established metastatic prostate cancer cell line, LNCaP. RESULTS: Increasing concentrations of curcumin promoted more apoptosis in the PcBra1 cells. Exposure to 10 and 25 µM curcumin induced apoptosis in 31.9 percent and 52.2 percent of cells, respectively. Late apoptosis was induced in 37 percent of cells after treatment with 10 µM curcumin and 35 percent of cells with a 25 µM treatment. Necrosis accounted for less than 10 percent of the death in these cells at those two concentrations. When curcumin was used at 50 µM, apoptosis was observed in 64.3 percent of the cells. Including late apoptosis and necrosis, 98.6 percent of the cells died in response to 50 µM curcumin. Results with the LNCaP cells were similar although late apoptosis was the main phenomenon at 25 µM. CONCLUSION: We have shown that curcumin acts on localized prostate cancer to induce apoptosis and may therefore be an option as a future therapeutic agent.