Abstract 467: Analysis of human hypoxia related miRNAs in MDM2 transfected prostate cancer cells

Abstract

Abstract Recent studies have shown the crucial role of miRNAs in regulating cancer initiation, progression and metastatic process via influencing gene expression patterns. However, the distinct mechanism by which miRNA regulates tumorigenesis remains as an area requiring detailed research investigations. In our earlier studies, we have demonstrated a positive correlation between MDM2 expression and hypoxia inducible factor -1alpha (HIF-1α) levels in both normoxic and hypoxic conditions using prostate cancer cell lines. Subsequently, we postulated that the upregulation of HIF-1α is most likely regulated by MDM2 in cancers cells that are positive for this gene expression. Hence, to confirm our hypothesis, we utilized miScript miRNA PCR Array analysis (Qiagen, USA) and compared the gene expression profile of the hypoxia signaling pathway in LNCaP (prostate cancer cells) and LNCaP-MST (MDM2 transfected prostate cancer cells) under normoxic conditions. This study was expected to outline how MDM2 impacts the differential expression of miRNAs and leading to enhancement of tumor angiogenesis via increase in HIF-1α or other genes of the hypoxia signaling pathway. Our preliminary data indicate that hsamiR99a5p, hsamiR125b5p, hsamiR1385p, hsamiR199b5p and hsalet7c5p are significantly upregulated in LNCaP-MST cells compared to LNCaP. In addition, some of the miRNAs such as hsalet7d5p, hsalet7e5p, hsalet7f5p, hsalet7g5p and hsalet7i5p are significantly downregulated in the same cells. Among the upregulated miRNAs, hsamiR125b5p emerged as an important gene that is known to downregulate the protein levels of hypoxia inducible factor 1alpha inhibitor (HIF1AN or FIH), which can normally inhibit the transcriptional activity of HIF-1α in both normoxic and hypoxic conditions. Therefore, overexpression of hsamiR125b5p seems to be associated with the increase in HIF-1α level. From the aforementioned findings, it is confirmed that the MDM2 overexpression is impacting miRNA levels such as hsamiR125b5p that are involved in hypoxia related signaling pathway. Thus, our results offer a convincing evidence that MDM2 can promote angiogenesis and increase metastatic potential of cancers through altering the miRNA expression levels. (The financial support from the Royal Dames of Cancer Research Inc., Ft. Lauderdale, Florida is gratefully acknowledged). Citation Format: Saad Ebrahim Alobid, Thiagarajan Venkatesan, Ali Alaseem, Khalid Alhazzani, Appu Rathinavelu. Analysis of human hypoxia related miRNAs in MDM2 transfected prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 467. doi:10.1158/1538-7445.AM2017-467