Abstract 2958: The novel protein kinase STK17A is a direct p53 target gene that mediates response to genotoxic and nutritional stress in a cancer cell context-dependent manner

Abstract

STK17A (DRAK1) is a largely uncharacterized serine/threonine kinase that belongs to the death-associated protein kinase family. Prior microarray studies demonstrated that STK17A is induced with cisplatin in testicular cancer-derived human embryonal carcinoma (EC) cells. We now demonstrate the STK17A in a novel p53 target gene that is induced by a variety of DNA damaging agents in a p53-dependent manner in a number of different cell contexts. A consensus and functional p53 response element was found upstream of the STK17A promoter and endogenous p53 was shown to bind to this site in a cisplatin-dependent manner. Knockdown of STK17A conferred resistance to cisplatin-induced growth suppression and apoptotic cell death in EC cells. This was associated with up-regulation of detoxifying and antioxidant genes and reduction in reactive oxygen species (ROS), whereas overexpression of STK17A increased ROS levels in EC cells. Interestingly, we found that STK17A is highly overexpressed in clinical glioblastoma (GBM) and cell lines compared to its expression in normal brain tissue and other cancers. High STK17A expression in GBM patients correlated with poor clinical outcome and decreased survival. STK17A knockdown in GBM cells decreased clonagenic cell growth, soft agar tumorigenicity, and survival in response to genotoxic and nutritional stress. Preliminary data will be presented implicating STK17A in the regulation of autophagy and the proximal autophagy component, ULK1. These findings indicate that STK17A may be added to a growing list of direct p53 target genes involved in autophagy that includes TIGAR, Sestrins, DAPK1 and DRAM and that by impacting autophagy STK17A may modulate response to genotoxic and nutritional stress in a cell context-depend manner. This study also suggests that STK17A is a potential novel prognostic maker and therapeutic target for GBM. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2958. doi:1538-7445.AM2012-2958

Expression profiling of cervical cancers in Indian women at different stages to identify gene signatures during progression of the disease

“…It is reported to be downregulated in many cancers and homozygous deletions are noted in melanoma cell line (etoposide-resistant) and laryngeal squamous cell carcinoma cell line [ 51 ]. Interestingly overexpression of STK17A has been reported in other cancers like glioblastoma where it has been implicated to correlate to poor prognosis in those patients [ 52 ]. In this study, VAV2 was specifically overexpressed in Stage I in the microarray data while STK17A was specifically overexpressed in Stage II.…”