Standard therapeutic approaches of cytotoxics and radiation in cancer are not only highly toxic, but also of limited efficacy in treatment of a significant number of cancer patients. The molecular analysis of the cancer genomes have shown a remarkable complexity and pointed to key genomic and epigenomic alterations in cancer. These discoveries are paving the way for targeted therapy approaches. However, although there are a large number of potential targets, only a few can regulate key cellular functions and intersect multiple signaling networks. The Aurora kinase family members (A, B, and C) are a collection of highly related and conserved serine-threonine kinases that fulfill these criteria, being key regulators of mitosis and multiple signaling pathways. Alterations in Aurora kinase signaling are associated with mitotic errors and have been closely linked to chromosomal aneuploidy in cancer cells. Several studies have shown amplification and/or overexpression of Aurora kinase A and B in hematologic malignancies and solid tumors. Over the past several years, Aurora kinases have become attractive targets. Several ongoing clinical trials and bench-based research are assessing the unique therapeutic potential of Aurora-based targeted therapy.Mol Cancer Ther; 9(2); 268-78. ©2010 AACR.

No abstract

Background MicroRNAs (miRNAs) are small noncoding RNAs that regulate the expression of approximately 30% of all human genes. They play important roles in numerous cellular processes including development, proliferation, and apoptosis. It is currently believed that miRNAs elicit their effect by silencing the expression of target genes. Here we show that microRNA-205 (miR-205) induces the expression of IL24 and IL32 tumor suppressor genes by targeting specific sites in their promoters. Methods Methods used in this study include transfection of small RNAs, quantitative-real-time-PCR, in-situ hybridization, fluorescence labeled in-situ hybridization, cell cycle, apoptosis, cell viability, migratory, clonability and invasion assays, immunoblotting, luciferase reporter, nuclear run-on and chromatin immunoprecipitation assays. Results Our results revealed that miR-205 is silenced in prostate cancer. Its re-expression induced apoptosis and cell cycle arrest. It also impaired cell growth, migration, clonability and invasiveness of prostate cancer cells. MicroRNA-205 induced tumor suppressor genes IL24 and IL32 at both mRNA and protein levels. Induction of in-vitro transcription and enrichment of markers for transcriptionally active promoters in IL24 and IL32 genes was observed in response to miR-205. Conclusion In this study we identify a new function for miR-205 to specifically activate tumor suppressor genes by targeting specific sites in their promoters. These results corroborate a new function that miRNAs have in regulating gene expression at the transcriptional level. The specific activation of tumor suppressor genes (e.g., IL24, IL32) or other dysregulated genes by microRNAs may contribute to the novel therapeutic approach in the treatment of prostate cancer.