Employing endogenous human peptides for eliminating migrating CSCs by targeting CXCR4 receptor in pancreatic ductal adenocarcinomas

Pancreatic cancer is expected to become the 2nd leading cause of cancer-related deaths by 2030. One of the reasons for such startling statistics is the presence of a subpopulation of highly plastic stem-like cells within the tumor. We have previously identified a distinct subset of these cancer stem cells (CSCs) characterized by CD133+CXCR4+ expression within the invasive front of patient tumors, which determined the metastatic phenotype of pancreatic cancer. Development and investigation of novel treatment regimens is imperative to specifically target and eradicate these migrating CSCs (mCSCs) to have a more effective treatment for pancreatic cancer. We here examine the effect of endogenous human peptides (such as EPI-X4) on patient-derived primary pancreatic cancer cells and establish these peptides as novel therapeutic strategy for combating the metastatic activity of pancreatic cancer.

Flow cytometry helped to characterize 14 different patient-derived pancreatic cancer cell lines to determine CSCs and mCSCs subpopulation. Transwell migration assays towards CXCR4 ligand SDF-1 verified the role of EPI-X4 and its derivatives. Western blotting, qPCR, IF and sphere formation assay were performed to delineate the downstream effectors of the most potent EPI-X4 derivatives. Clonogenic assay and silica nanoparticles were used to study the combinatorial therapy and in vivo delivery system, respectively. JM21 (EPI-X4 derivative) strongly inhibited migratory capacity of primary pancreatic cancer cells. JM21 increased Cdh1 expression by suppression of Snai1 via Shh pathway. It decreased SDF-1 induced phosphorylation of AKT and IKBa and self-renewal capacity of the cells. It also sensitized selected cell lines towards gemcitabine. Furthermore, in serum conditions, silica nanoparticle encapsulated JM21 was found to be stable and active, proving as a valuable delivery system for in-vivo study.

We elucidate the deregulation of different molecular pathways involved in EMT, stemness and cytoskeletal dynamics while targeting CXCR4-SDF-1 signalling using human endogenous peptides. We demonstrate in a preclinical setup that these peptides can abrogate the metastatic capacity of patient-derived pancreatic cancer cells by selective targeted elimination of mCSCs.

Publication History

Article published online:
07 September 2021