Paracrine HGF promotes EMT and mediates the effects of PSC on chemoresistance by activating c-Met/PI3K/Akt signaling in pancreatic cancer in vitro

Pancreatic stellate cells (PSCs) play key roles in the pancreatic tumor microenvironment and are considered to contribute to chemoresistance. PSCs can participate in malignant behaviors of pancreatic carcinoma (PC) by secreting hepatocyte growth factor (HGF). The objective of this research was to explore the potential molecular mechanism of HGF on gemcitabine (GEM) chemoresistance of PC. HGF, c-Met, E-Cadherin and Vimentin levels were examined by quantitative real-time polymerase chain reaction (qRT-PCR). The changes of HGF level were detected by ELISA. The half maximal inhibitory concentration, the growth inhibitions and apoptosis of pancreatic cancer cells (PCCs) were respectively assayed using CCK-8 and flow cytometry. Associated proteins were measured using western blot and cell immunofluorescence assay. PSCs strongly expressed HGF, and its receptor c-Met was expressed in PCCs. PCCs exerted a positive regulative effect on HGF production. HGF neutralizing antibody AMG102 could effectively reduce the HGF level in PSC-conditioned medium (PSC-CM). PSC-CM promoted chemoresistance in PCCs. When exposed to PSC-CM, PCCs underwent epithelial-to-mesenchymal transition (EMT), and c-Met was also activated. Recombinant human HGF had the same protective effect. Blocking the HGF/c-Met axis with a c-Met inhibitor PHA665752 and AMG102 reduced the phosphorylation level of c-Met (p-c-Met) and attenuated EMT and chemoresistance. P-c-Met overexpression resulted in activation of the PI3K/Akt pathway, and inhibition of PI3K/Akt signaling with LY294002 reversed chemoresistance and EMT. PSCs can activate the c-Met/PI3K/Akt pathway in PCCs via paracrine HGF, induce EMT of PCCs and inhibit cancer cell apoptosis, thus enhance chemoresistance to Gem in PCCs. •Tumor microenvironment plays a starring role in the development of pancreatic cancer, stroma-tumor interaction creates a tumor-supportive microenvironment to facilitate cell proliferation, migration, invasion, and even chemoresistance.•Pancreatic stellate cells (PSCs) are a key cellular component of the tumor microenvironment and considered to contribute to chemochemoresistance. Multiple cytokines and growth factors derived from PSCs are involved in malignant cancer progression, including hepatocyte growth factor. Therefore, therapeutic targeting of PSCs has emerged as a promising strategy to improve outcomes for pancreatic adenocarcinoma.•Epithelial-to-mesenchymal transition is not only a crucial hallmark of tumor progressio