Cyclin-Dependent Kinase Inhibitor p27(Kip1) Controls Growth and Cell Cycle Progression in Human Uterine Leiomyoma

The molecular mechanism of the cell-cycle machinery in uterine leiomyoma has not yet been fully elucidated. Among the various types of cell-cycle regulators, p27(Kip1)(p27) is considered to be a potent tumor suppressor. To provide further molecular basis for understanding the progression of uterine leiomyoma, our objective was to evaluate the expression level of p27 in normal myometrium and uterine leiomyoma tissue and its effect on cytogenic growth. Western blot analysis, real-time polymerase chain reaction (PCR) and immunohistochemical staining revealed that p27 protein and messenger RNA were down-regulated in uterine leiomyoma tissue and cultured cells compared to normal myometerium. Full-length human p27 cDNA was transferred using a replication-deficient recombinant adenoviral vector (Ad.p27) into uterine leiomyoma cells and evaluated the effect on cell proliferation. Transfection of Ad.p27 into uterine leiomyoma cells resulted in the induction of apoptosis, reduction in viability and proliferation of uterine leiomyoma cells. Our results suggest a new paradigm that down-regulated p27 protein expression is the possible underlying mechanism for the growth of uterine leiomyoma and over-expression of p27 induces cell death. This study provides better understanding of the control exerted by p27 in regulating growth and disease progression of uterine leiomyoma.

Induction of apoptosis by Hibiscus protocatechuic acid in human uterine leiomyoma cells / 부인종양

OBJECTIVE: Hibiscus protocatechuic acid (PCA) is a food-derived polyphenol antioxidants used as a food additive and a traditional herbal medicine. In this study, PCA was to determine its effect on cell proliferation and cell cycle progression in primary cultured human uterine leiomyoma cells. METHODS: The effect of PCA on cell proliferation and cell cycle progression was examined in the primary cultured human uterine leiomyoma cells. MTT reduction assay was carried out to determine the viability of uterine leiomyoma cells. Cell cycle analysis for Hibiscus protocatechuic acid treated leiomyoma cells was done by FACS analysis. DNA fragmentation assay was performed to determine fragmentation rate by PCA in leiomyoma cells. Western blot analysis was done using anti pRB, anti-p21(cip1/waf1), anti-p53, anti-p27(kip1), anti-cyclinE, anti CDK2 antibodies to detect the presence and expression of these proteins in PCA treated myoma cells. RESULTS: PCA induced growth inhibition in a dose dependent manner, treatment with 5 mmol/L PCA blocked 80% cell growth. FACS results showed that there was increased the percentage of cells in sub G1. DNA fragmentation assay by ELISA was done to find the rate of apoptosis. Apoptosis took place but in a dose dependent manner. From Western blot analysis it revealed PCA induced the expression of p21(cip1/waf1) and p27(kip1) increasingly and was not mediated by p53. Caspase-7 pathway was activated and dephosphorylation of pRB took place. CONCLUSION: In Conclusions, PCA, a polyphenol antioxidant, inhibited cell proliferation and induced cell cycle arrest at sub G1 phase by enhancing the production of p21cip1/waf1 and p27kip1. These results indicate that PCA will be a promising agent for use in chemopreventive or therapeutics against human uterine leiomyoma.

Augmentation of Sodium Butyrate-induced Apoptosis by Phosphatidylinositol 3-kinase Inhibition in the Human Cervical Cancer Cell-line / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Sodium butyrate (NaBT) is principally a histone deacetylase (HDAC) inhibitor, and it has the potential to arrest HPV-positive carcinoma cells at the G1 to S phase transition of the cell cycle. The aim of study was to determine whether phosphatidylinositol 3-kinase (PI3K) inhibition can enhance the inhibitory effect of NaBT on a human cervical cancer cell line (HeLa). MATERIALS AND METHODS: Cervical cancer cells (HeLa) were treated with NaBT alone or in combination with the PI3K inhibitors wortmannin or LY294002. Cell viability analysis and FACS analysis were carried out. The expressions of the cell cycle related proteins were evaluated by Western-blot analysis. RESULTS: Inhibition of PI3K enhanced NaBT-mediated apoptosis and this decreased the HeLa cell viability. Either wortmannin or LY294002, combined with NaBT, enhanced the activation of caspase 3 and caspase 9, and this enhanced the subsequent cleavage of poly (ADP-ribose) polymerase (PARP). Cervical cancer cells were arrested in the subG1 and G2/M phase, as was detected by FACS analysis. NaBT treatment in combination with PI3K inhibitors showed the increased expression of the CDK inhibitors p21(Cip1/Waf1) and p2(7Kip1), in a p53 dependent manner, and also the increased dephosphorylation of Rb whereas there was a reduction in the expression levels of cyclin A, cyclin D1 and cyclin B1. CONCLUSION: The results demonstrate that inhibition of PI3K enhances NaBT-mediated cervical cancer cell apoptosis through the activation of the caspase pathway. Moreover, these findings will support future investigation using the PI3K inhibitors in combination with adjuvant treatment for treating carcinoma of the cervix.