Histone Demethylase Kdm3a: Epigenetic Target For Pancreatic Ductal Adenocarcinoma (Pdac)

Purpose: A growing body of evidence suggests that cancer stem cells/tumor initiating cells (CSC/TIC) within a solid tumor including in pancreatic cancer initiate and sustain tumor growth. Our preliminary data implicates KDM3A (histone lysine demethylase 3A)/Jmjd1A (jumonji domain demethylase 1A), non-heme iron (II)- α-ketoglutarate (kg) dependent enzyme, as a prime regulator of stems cell self-renewability for cancer progression and is overexpressed in PDAC. Hypoxia most prominently controls malignant properties of cancer cells by stimulating hypoxia inducible factor 1 (HIF1). The fact that HIF1 binds to its responsible elements (HREs) in the KDM3A promoters and subsequently up-regulates its expression could explain why hypoxia exacerbates malignancy. Based on these observations, we hypothesize that hypoxia induces KDM3A that regulates self-renewability of CSC/TIC, thereby promoting tumor initiation. Experimental Procedure: We have used RNA technology to silence KDM3A in different pancreatic cancer cells and overexpressed KDM3A in non-cancerous immortal pancreatic ductal epithelial cells (HPNE). We have determined KDM3A expression in pancreatic cancer patient9s samples. We performed quantitative chromatin immunoprecipitation (ChIP) analysis as an indicator of KDM3A recruitment. Results: KDM3A was overexpressed in human pancreatic cancer patient tissue samples particularly in the area of the pancreatic ducts and also in pancreatic cancer cells. Knockdown of KDM3A in pancreatic cancer cells significantly reduced the enzyme activity resulting in increased substrate (H3K9Me2) expression. KDM3A knockdown cells decreased oncogenic potential as demonstrated by inhibition of proliferation, clonogenicity, sphere-forming potential, migration and tumor formation in orthotopic mouse model (immunocompromised mice). KDM3A overexpressed transformed HPNE cells increased oncogenic potential as evidenced by foci formation, pancosphere formation and tumor formation in orthotopic mouse model. ChIP following deep sequencing analysis suggested that KDM3A recruited one of the CSC stem cell markers, DCLK1. N-oxaloglycine, α-kg inhibitor, inhibited KDM3A enzyme activity and spheroid formation in overexpressing HPNE cells and in pancreatic cancer cells.Conclusions: KDM3A was overexpressed in PDAC. ChIP-seq analysis revealed that KDM3A recruitment was higher when DCLK1 is expressed. Taken together, KDM3A appears to be responsible, at least in part, for PDAC progression and could be a novel preventive or therapeutic target in pancreatic cancer. Citation Format: Satheesh K. Sainathan, Santanu Paul, Kanagaraj Palaniyandi, Dharmalingam Subramaniam, Satish Ramalingam, Ossama W. Tawfik, Tomoo Iwakuma, Danny R. Welch, Subhash B. Padhye, Shrikant Anant, Animesh Dhar. Histone demethylase KDM3A: Epigenetic target for pancreatic ductal adenocarcinoma (PDAC). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2338. doi:10.1158/1538-7445.AM2015-2338