Targeting FTO Suppresses Pancreatic Carcinogenesis via Regulating Stem Cell Maintenance and EMT Pathway

SIMPLE SUMMARY: Current treatment strategies for pancreatic cancer (PC) yield poor survival outcomes. It is thus essential to identify factors that orchestrate pancreatic tumorigenesis and contribute to therapeutic resistance. Fat mass and obesity-associated protein (FTO) play a crucial role in demethylating N6-methyladenosine (a known and prevalent modification in eukaryotic RNA). Notably, recent pioneering studies have identified a significant association of FTO overexpression with the cancer progression of various types. Nevertheless, our current understanding of the role of FTO in modulating biological processes relevant to PC is in its infancy. We demonstrate that PC cells expressed higher FTO levels than the normal pancreatic ductal epithelial (HPDE) cells. Furthermore, both lentiviral-mediated genetic and CS1-mediated pharmacological inhibition of FTO impaired PC cell growth, survival, migratory, and invasiveness capabilities. Additionally, FTO loss led to the reversal of EMT traits, impaired tumorsphere formation, and reduced the expression of cancer stem cells (CSC) markers. In agreement, FTO-depleted PC cells displayed impaired tumorigenic capability in a xenograft model. Our study thus demonstrates the functional importance of FTO overexpression in the PC tumorigenicity and maintenance of CSCs via EMT regulation. Therefore, FTO may represent an attractive therapeutic target for PC. ABSTRACT: N(6)-methyladenosine (m(6)A) is the most prevalent post-transcriptional RNA modification regulating cancer self-renewal. However, despite its functional importance and prognostic implication in tumorigenesis, the relevance of FTO, an m(6)A eraser, in pancreatic cancer (PC) remains elusive. Here, we establish the oncogenic role played by FTO overexpression in PC. FTO is upregulated in PC cells compared to normal human pancreatic ductal epithelial (HPDE) cells. Both RNAi depletion and CS1-mediated pharmacological inhibition of FTO caused a diminution of PC cell proliferation via cell cycle arrest in the G1 phase and p21cip1 and p27kip1 induction. While HPDE cells remain insensitive to CS1 treatment, FTO overexpression confers enhancements in growth, motility, and EMT transition, thereby inculcating tumorigenic properties in HPDE cells. Notably, shRNA-mediated FTO depletion in PC cells impairs their mobility and invasiveness, leading to EMT reversal. Mechanistically, this was associated with impaired tumorsphere formation and reduced expression of CSCs markers. Furthermore, FTO depletion in PC cells weakened their tumor-forming capabilities in nude mice; those tumors had increased apoptosis, decreased proliferation markers, and MET conversion. Collectively, our study demonstrates the functional importance of FTO in PC and the maintenance of CSCs via EMT regulation. Thus, FTO may represent an attractive therapeutic target for PC.