Anticancer and therapeutic efficacy of XPO1 inhibition in pancreatic ductal adenocarcinoma through DNA damage and modulation of miR-193b/KRAS/LAMC2/ERK/AKT signaling cascade

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and grave malignancies with confined and ineffective therapeutic options. XPO1 is a critical regulator of nuclear export and activation of tumor suppressor proteins. The present study evaluated the therapeutic potential and molecular mechanisms of XPO1 inhibition against PDAC. Firstly, we observed significant overexpression of XPO1 transcript in 179 PDAC patients than 171 normal pancreatic tissues in TCGA transcriptomic dataset. Higher XPO1 transcript levels displayed worse overall and disease-free survival. Further, we confirmed significant upregulation of XPO1 in a panel of PDAC cells. Eltanexor treatment resulted in significant inhibition of cell viability, clonogenic growth, migration, and epithelial-mesenchymal transition (EMT), along with the induction of cell cycle arrest. Mechanistically, eltanexor modulated the expression of key proteins including p21, p27, p53, cyclin B1, cyclin D1, c-Myc, N-cadherin, vimentin, E-cadherin associated with the cell viability, growth, cell cycle and EMT. Additionally, the eltanexor treatment resulted in marked increase in expression of γH2AX, and cleaved PARP, cleaved caspase-9 leading to induction of DNA damage and apoptosis of PDAC cells, respectively. Moreover, eltanexor treatment regulated the expression of key non-coding RNAs including miR193b, DINO, MALAT-1, H19, and SOX21-AS1 linked with tumorigenesis. Our results revealed a correlation among miR193b/KRAS/LAMC2, XPO1/KRAS, and LAMC2/KRAS. The findings also revealed that eltanexor treatment rescued the expression of miR193b which acts as a sponge for LAMC2 and KRAS resulting in the suppression of AKT/ERK downstream signaling cascade in PDAC. Interestingly, the combination of eltanexor with gemcitabine showed significant anticancer activity in PDAC cells. Altogether, our findings revealed the crucial role of XPO1 in modulating the expression of oncogenic proteins, ncRNAs, and DNA damage during PDAC progression as well as identified novel therapeutic miR-193b/KRAS/LAMC2/ERK/AKT axis.