TNFα and TGFβ-1 synergistically increase the cancer stem cell properties of MiaPaCa-2 cells

Increased serum concentrations of tumor necrosis factor a (TNF alpha) and transforming growth factor beta-1 (TGF beta-1) in the blood of patients with pancreatic cancer (PC) have previously been demonstrated. In addition, exogenous exposure to these cytokines promotes various cancer cell invasive and cancer stem cell (CSC) phenotypes. However, their importance in pancreatic CSCs remains elusive. In the present study, the effects of TNF alpha and TGF beta-1 on the human PC cell line MiaPaCa-2 were examined. Using flow cytometry, it was revealed that TNF alpha and TGF beta-1 synergistically increase cluster of differentiation (CD) 44v6, CD133 and ATP-binding cassette transporter G2 (ABCG2) expressing populations in adherent tumor cell culture conditions. Furthermore, a similar trend was observed in cells pretreated with these cytokines grown in sphere forming culture conditions. Similar to previous studies, TNF alpha treatment increased the proportion of epidermal growth factor receptor (EGFR) expressing cells in adherent culture, and this data was further supported by the results of the sphere formation assay, in which the subculture with a high proportion of EGFR expressing cells exhibited the most efficient sphere forming ability. However, the proportion of vascular endothelial growth factor receptor 1 (VEGFR1) expressing cells did not increase upon treatment with these cytokines individually or in combination. This data was subsequently supported by the results of the wound healing assay in which cytokine treatment did not increase the migration of cells. The MTT cell proli-feration and cytotoxicity assay revealed that TNF alpha + TGF beta-1 treatment significantly increased cell proliferation and daunorubicin resistance, but not gemcitabine resistance. In conclusion, the data of the current study provide a mechanistic association between TNF alpha, TGF beta-1 and the CSC properties of MiaPaCa-2 cells. In addition, it suggests that targeting TNF alpha and TGF beta-1 is beneficial for improving the therapeutic efficacy of treatments for patients with PC.