Abstract 1858: Analyzing the impact of MDM2 overexpression on cell cycle pathway-related genes using polymerase chain reaction array

Abstract

Abstract The human homologue of the mouse double minute 2 (MDM2) oncogene has been well characterized as a negative regulator of the tumor suppressor p53. It has been established that p53 regulates genes that are involved in cell cycle arrest, apoptosis, DNA repair and senescence. MDM2 interacts primarily with p53 in an autoregulatory negative feedback loop and targets it for ubiquitylation and proteasomal degradation there by attenuating p53 cell cycle arrest and apoptosis functions. Studies have shown that MDM2 also exerts its effects via p53 independent pathways. These p53-independent functions of MDM2 may have a role in cancer etiology and progression, yet the exact function and significance of these interactions are not fully understood. MDM2 is overexpressed in more than 40 different types of malignancies, including wide varieties of carcinomas and sarcomas, which is believed to be associated with worse clinical prognosis and increased likelihood of distant metastases. Hence, MDM2 is proving to be a key player in human cancer and thus an important target for therapeutic intervention. In this study, we aimed to investigate the effects of MDM2 overexpression on cell cycle pathways by using LNCaP prostate cancer cells and MDM2 transfected LNCaP-MST. The LNCaP-MST cells expressed at least 10-folds higher levels of MDM2 mRNA due to transfection. We used the Human Cell Cycle PCR array to compare the gene expression profiles of LNCaP and LNCaP-MST cells. Our experimental results clearly indicated that MDM2 modulates the expression of cell cycle related genes. The following genes were found to be significantly down-regulated in LNCaP-MST cells compared to LNCaP: CCND2, GADD45A, RB1, RBBP8, CDKN1A and TP53. Genes such as BIRC5, CDK1 were found to be significantly up-regulated. Heat map and scatter plot analysis further confirmed the alterations in the expression levels of these genes following the MDM2 overexpression. In addition, cluster analysis further denoted that the gene expression patterns positively correlated with cell proliferation and tumor growth. Our experimental results offer conclusive evidence that MDM2 can impact the cancer growth and metastatic potential by altering the gene expressions in the cell cycle pathway. (The financial support from the Royal Dames of Cancer Research Inc., Ft. Lauderdale is gratefully acknowledged). Citation Format: Priya Dondapati, Thiagarajan Venkatesan, Appu Rathinavelu. Analyzing the impact of MDM2 overexpression on cell cycle pathway-related genes using polymerase chain reaction array. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1858.