Pancreatic stellate cells: the top managers of the pancreatic tumor microenvironment.

Background Stellate pancreatocytes, being cells - producers of stromal components, actively interact with cancer cells, determine the formation of a stromal barrier between the latter and thereby provide tumor chemoresistance. Objective The review is devoted to the analysis of recent data on the role of stellate pancreatocytes in the formation of the stromal microenvironment of pancreatic tumors, molecular mechanisms through which the regulation and realization of stellate cell functions is carried out. Methods Data processing was carried out by the method of complex material analysis. Results. Stellate pancreatocytes (PSC) exhibit phenotypically and functionally two states: inactive and active. PSC activation is carried out by cells of the developing tumor through a variety of molecular mediators. Activation triggers for PSC are Yes-associated protein, TGF-β1, miRNA let-7d, IL-8, MCP1, TGF-β2, IGFBP2, and others. 10 actively expressed genes were identified: TP53, SRC, IL6, JUN, ISG15, CAD, STAT1, OAS3, OAS1, VIM during co-cultivation of a cancer cell line (PCC) with PSC. PSC deactivation is associated with speckle-type mediator POZ (SPOP) acting through nuclear factor-kappaB, transretinoic acid (ATRA). Exhibiting their activity, PSCs express several stem cell markers, α-SMA (α-actin of smooth muscle cells), vimentin, α ITGA 11 (collagen type I receptor), α5 integrin receptor ITGA5 (fibronectin receptor), hyaluronic acid, hyaluronan synthase 2 (HAS2), hyaluronidase 1 (HYAL1), BAG3 , matrix metallopeptidase 2 (MMP2), Nodal protein, miR-1246 and miR-1290, miR-210, CCN2 (connective tissue growth factor), TRPV1, SP and CGRP (Calcitonin gene-related peptide) and many other factors. Сonclusion. Stellate pancreatocytes, being producers of the interacinar stroma, are activated by various factors (TNF-α, IL-6, MCP-1, ATP, and HMGB1, etc.), including factors produced by tumor cells of the pancreas, and act as regulators of proliferation, migration, and suppression apoptosis of the latter. An increase in the expression of α ITGA 11 (type I collagen receptor), α5 integrin receptor ITGA5 (fibronectin receptor), metallopeptidases, Nodal protein, miR-1246, miR-1290, and miR-210 is observed in tumor tissue, that indicates the activation of these cells. The maintenance of the active state of PSC is provided by tumor cells, for which stellate pancreatocytes are partners in the progression of the neoplastic process. Further study of the mechanisms of interaction in the PSC-tumor cell system creates the prospect of revealing levers of influence on the pathogenesis of pancreatic tumors.