Apoptotic Effects of Genistein, Biochanin-A and Apigenin on LNCaP and PC-3 Cells by p21 through Transcriptional Inhibition of Polo-like Kinase-1

Natural isoflavones and flavones are important dietary factors for prostate cancer prevention. We investigated the molecular mechanism of these compounds (genistein, biochanin-A and apigenin) in PC-3 (hormone-independent/p53 mutant type) and LNCaP (hormone-dependent/p53 wild type) prostate cancer cells. A cell growth rate and apoptotic activities were analyzed in different concentrations and exposure time to evaluate the antitumor activities of genistein, biochanin-A and apigenin. The real time PCR and Western blot analysis were performed to investigate whether the molecular mechanism of these compounds are involving the p21 and PLK-1 pathway. Apoptosis of prostate cancer cells was associated with p21 up-regulation and PLK-1 suppression. Exposure of genistein, biochanin-A and apigenin on LNCaP and PC-3 prostate cancer cells resulted in same pattern of cell cycle arrest and apoptosis. The inhibition effect for cell proliferation was slightly greater in LNCaP than PC-3 cells. In conclusion, flavonoids treatment induces up-regulation of p21 expression, and p21 inhibits transcription of PLK-1, which promotes apoptosis of cancer cells.

Expression of Cell Cycle Regulators During Smooth Muscle Cell Proliferation After Balloon Catheter Injury of Rat Artery

Intimal hyperplasia is defined as the abnormal migration and proliferation of vascular smooth muscle cells (VSMCs) with deposition of extracellular matrix. However, the cell cycle regulatory mechanisms of injury-induced VSMC proliferation are largely unknown. To examine the expression kinetics of cell cycle regulatory factors which is known to be worked positively or negatively, we used rat balloon injury model. Marked induction of proliferating cell nuclear antigen (PCNA), G1/S cyclin-dependent kinase (cdk2), and its regulatory subunit (cyclin E) occurred between 1 and 3 days after balloon arterial injury, and this was sustained for up to 7 days and then declined. However, the induction of the negative regulators, p21 and p27, occurred between 3 and 5 days of injury, peaked after 7 and 14 days and was then sustained. VSMC proliferation after balloon catheter injury of the rat iliac artery is associated with coordinated expression of positive (cdk2, cyclin E and PCNA) and negative (p21, p27) regulators. Cell cycle regulators such as cdk2, cyclin E, p21, p27 may be suitable targets for the control of intimal hyperplasia.

p53 protein expression and its prognostic importance in patients with nodal non-Hodgkin's lymphoma

To determine whether the p53 expression might be a predictor for treatment sponse and overall survival in nodal non-Hodgkin's lymphoma (NHL), we analyzed e expression of p53 in 69 NHL patients. p53 protein expression was analyzed by munohistochemistry with long-term follow up (1-148 months: median 12.2). p53 pression was noted in 23/69 (33.3%) patients. Complete response (CR) rate to stemic chemotherapy was correlated with stage (I/II) (p=0.038), but not with 3 expression (p=0.2856). Poor overall survival was associated with stage =0.0010) or IPI score (p=0.0076), but not with p53 expression (p=0.8601). From ratification analysis by stage, in stage III/IV patients, the p53 positive oup had a trend to be associated with poor overall survival than the p53 gative group. Multivariate analysis revealed that p53 positive group was sociated with less CR rate compared to the p53 negative group (p=0.046), ereas overall survival was correlated with stage (p=0.0320), not with p53 atus. p53 expression was associated with less CR rate in patients with DLBL. rther studies with large numbers of samples and homogenous group of NHL are eded to determine the prognostic value of cell cycle regulator, p53 in NHL.