ABSTRACT
PURPOSE: The aims of this study were to investigate the expression levels of proteins involved in cell cycle regulation in specimens of bladder cancer and to correlate them with the clinicopathological characteristics, proliferative activity and survival. METHODS: Eighty-two specimens obtained from patients affected by muscle-invasive bladder cancer were evaluated immunohistochemically for p53, p21 and cyclin D1 expression, as well as for the tumour proliferation index, Ki-67. The statistical analysis included Kaplan-Meier curves with log-rank test and Cox proportional hazards models. RESULTS: In univariate analyses, low Ki-67 proliferation index (P = 0.045) and negative p21 immunoreactivity (P = 0.04) were associated to patient's overall survival (OS), but in multivariate models p21 did not reach statistical significance. When the combinations of the variables were assessed in two separate multivariate models that included tumour stage, grading, lymph node status, vascular invasion and perineural invasion, the combined variables p21/Ki-67 or p21/cyclin D1 expression were independent predictors for OS; in particular, patients with positive p21/high Ki-67 (P = 0.015) or positive p21/negative cyclin D1 (P = 0.04) showed the worst survival outcome. CONCLUSIONS: Important alterations in the cell cycle regulatory pathways occur in muscle-invasive bladder cancer and the combined use of cell cycle regulators appears to provide significant prognostic information that could be used to select the patients most suitable for multimodal therapeutic approaches.
Subject(s)
Cell Cycle Proteins/biosynthesis , Urinary Bladder Neoplasms/diagnosis , Cell Cycle , Cell Proliferation , Cohort Studies , Cyclin D , Cyclin-Dependent Kinase Inhibitor p21/biosynthesis , Cyclins/biosynthesis , Female , Follow-Up Studies , Humans , Ki-67 Antigen/biosynthesis , Male , Multivariate Analysis , Prognosis , Survival Rate , Tumor Suppressor Protein p53/biosynthesis , Urinary Bladder Neoplasms/metabolism , Urinary Bladder Neoplasms/pathologyABSTRACT
Solid tumors develop resistance to retinoids during carcinogenesis. One of the strategies to overcome this resistance may include the combination of these molecules with other differentiating, cytotoxic or chromatin-remodelling agents. We analysed the anti-proliferative activity of two histone-deacetylase inhibitors (HDACIs), Trichostatin A (TSA) and sodium phenylbutyrate (PB), alone or combined with retinoids, all-trans retinoic acid (ATRA) and Ro 41-5253, on two human breast cancer cell lines: the hormone-dependent MCF-7 and the hormone-independent MDA-MB-231. These lines responded differently to retinoids: MCF-7 were sensitive, whilst MDA-MB-231 were rather resistant. When the retinoids were combined with HDACIs, these molecules potentiated the retinoid activity on growth inhibition, especially for the association Ro 41-5253 and TSA. By FACS analysis, we observed that the anti-proliferative effects were only partially due to pro-apopotic mechanisms, suggesting a cell-cycle block. The efficacy of the retinoids/HDACIs combinations could represent a new strategy in breast cancer chemotherapy, allowing inhibition of both ER + and ER- cell populations.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/pharmacology , Breast Neoplasms/drug therapy , Breast Neoplasms/enzymology , Histone Deacetylase Inhibitors , Hydroxamic Acids/pharmacology , Phenylbutyrates/administration & dosage , Acetylation , Benzoates/administration & dosage , Benzoates/pharmacology , Cell Line, Tumor , Chromans/administration & dosage , Chromans/pharmacology , Drug Synergism , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/pharmacology , Flow Cytometry , Histones/metabolism , Humans , Hydroxamic Acids/administration & dosage , Tretinoin/administration & dosage , Tretinoin/pharmacologyABSTRACT
BACKGROUND: It has been observed, in preclinical and clinical studies, that retinoids may interfere with the carcinogenic process in different ways such as the control of proliferation, differentiation and apoptosis. MATERIALS AND METHODS: We evaluated the in vitro efficacy of some synthetic retinoids (RAR-alpha, beta and gamma; RXR-alpha agonists and RAR-alpha antagonist) and compared these to the panagonist all-trans retinoic acid in inhibiting growth of the human melanoma cell line, SK MEL 28. We estimated, in parallel, apoptosis as a function of the treatment and, by RT-PCR, we analysed the effects of retinoids on the transcriptional profile of relevant genes, such as retinoid receptors and regulatory proteins. RESULTS: We observed a marked antiproliferative rate with the RAR-gamma selective agonist RO 44-4753 and the RAR-alpha selective antagonist RO 41-5253; on the contrary, the other synthetic retinoids exhibited a rather low efficacy. All the tested retinoids appeared to activate the RAR-beta gene and major expression was evidenced following RO 44-4753 and RO 41-5253 treatment. CONCLUSION: Among the tested retinoids, RO 41-5253 exhibited marked effects on proliferation and RARs mRNA expression and its action appeared mainly related to a cell-cycle arrest rather than an apoptotic mechanism.
