Differential effects of collagen and fibronectin coating on human primary pancreatic cancer cell behavior

Poor treatment effect in pancreatic cancer is attributed to profound resistance to chemotherapy of the tumor, which is largely driven by the complex tumor microenvironment (TME). Among TME components that are secreted by pancreatic stellate cells (PSCs; also known as cancer-associated fibroblasts), the extracellular matrix (ECM) proteins collagen type I (COL) and fibronectin (FN) have been implicated in promoting chemoresistance and tumor progression. However, their precise contributions remain unclear. Six pancreatic cancer cell (PCC) lines were utilized, comprising three primary in-house established lines (PCC-1, PCC-2, PCC-7) and three immortalized lines (BxPC-3, Mia PaCa-2, Panc-1). Cells were cultured on surfaces coated with COL or FN, or were exposed to PSC-conditioned medium (PSC-CM; control). Functional assays were conducted to evaluate changes in cell growth, adhesion, colony formation, migration, and chemosensitivity. The proteomic profile of PSC-CM was analyzed using mass spectrometry. Lastly, cellular protein expression levels were assessed via immunoblotting. Exposure to COL and FN coating exhibited predominantly growth-inhibitory and growth-permissive effects on PCCs, respectively, though considerable heterogeneity was observed across PCC lines. COL but not FN coating and PSC-CM exposure inhibited colony formation. Increased migration was observed in three and five of the six PCC lines following exposure to COL coating and PSC-CM, respectively. Exposure to COL and FN coating, as well as PSC-CM, all reduced sensitivity to gemcitabine (GEM) and 5-fluorouracil (5-FU) while FN and COL coating led to the maximum observed reduction in sensitivity to GEM and 5-FU, respectively. Mass spectrometry analysis of PSC-CM revealed abundance of proteins related to ECM organization, glycometabolic regulation, and cancer cell growth. Immunoblotting revealed differentially altered levels of key regulators of pancreatic cancer growth, including integrins α2β1 and α5β1, cadherins, phosphorylation of ERK and FAK, across PCCs following exposure to PSC-CM, or COL/FN coating. This study underscores the role of PSCs and ECM components COL and FN in promoting PCC growth and altered chemosensitivity and suggests that the TME composition may significantly influence treatment efficacy.