Orai1 Channel Regulates Human-Activated Pancreatic Stellate Cell Proliferation and TGFβ1 Secretion through the AKT Signaling Pathway.

Silviya Radoslavova,Stéphanie Guénin,Natalia Prevarskaya,Kateryna Kondratska,Halima Ouadid-Ahidouch,Isabelle Dhennin-Duthille,Mathieu Gautier,Thibaut Lefebvre,Antoine Folcher

doi:10.3390/cancers13102395

Silviya Radoslavova, Stéphanie Guénin + Show 7 more

Open Access

https://doi.org/10.3390/cancers13102395

Copy DOI

Abstract

Simple SummaryActivated pancreatic stellate cells (aPSCs), the main source of cancer-associated fibroblasts in pancreatic ductal adenocarcinoma (PDAC), are well known as the key actor of the abundant fibrotic stroma development surrounding the tumor cells. In permanent communication with the tumor cells, they enhance PDAC early spreading and limit the drug delivery. However, the understanding of PSC activation mechanisms and the associated signaling pathways is still incomplete. In this study, we aimed to evaluate the role of Ca2+, and Orai1 Ca2+ channels, in two main PSC activation processes: cell proliferation and cytokine secretion. Indeed, Ca2+ is a versatile second messenger implicated in the regulation of numerous biological processes. We believe that a better comprehension of PSC Ca2+ -dependent activation mechanisms will bring up new crucial PDAC early prognostic markers or new targeting approaches in PDAC treatment.Activated pancreatic stellate cells (aPSCs), the crucial mediator of pancreatic desmoplasia, are characterized, among others, by high proliferative potential and abundant transforming growth factor β1 (TGFβ1) secretion. Over the past years, the involvement of Ca2+ channels in PSC pathophysiology has attracted great interest in pancreatic cancer research. We, thus, aimed to investigate the role of the Orai1 Ca2+ channel in these two PSC activation processes. Using the siRNA approach, we invalided Orai1 expression and assessed the channel functionality by Ca2+ imaging, the effect on aPSC proliferation, and TGFβ1 secretion. We demonstrated the functional expression of the Orai1 channel in human aPSCs and its implication in the store-operated Ca2+ entry (SOCE). Orai1 silencing led to a decrease in aPSC proliferation, TGFβ1 secretion, and AKT activation. Interestingly, TGFβ1 induced a higher SOCE response by increasing Orai1 mRNAs and proteins and promoted both AKT phosphorylation and cell proliferation, abolished by Orai1 silencing. Together, our results highlight the role of Orai1-mediated Ca2+ entry in human aPSC pathophysiology by controlling cell proliferation and TGFβ1 secretion through the AKT signaling pathway. Moreover, we showed a TGFβ1-induced autocrine positive feedback loop by promoting the Orai1/AKT-dependent proliferation via the stimulation of Orai1 expression and function.

Highlights

Extensive desmoplastic stroma is the central pathological feature of pancreatic ductal adenocarcinoma (PDAC), responsible for the tumor’s development, progression, metastasis, and treatment resistance
We investigated Orai1 channel expression, by Western blotting, which revealed its presence in the PS-1 (Figure 1(Ab)) and RLT (Figure 1(Db)) human-activated pancreatic stellate cells (PSCs), and by immunofluorescence staining for PS-1 (Figure S1A)
It is well known that Orai1 is one of the key players of store-operated Ca2+ entry (SOCE) in the majority of cell types, we evaluated this possibility by using the small interfering RNA (siRNA) approach

Summary

Introduction

Extensive desmoplastic stroma is the central pathological feature of pancreatic ductal adenocarcinoma (PDAC), responsible for the tumor’s development, progression, metastasis, and treatment resistance. This fibrotic stroma is mainly composed of cancer-associated fibroblasts (CAFs), called pancreatic stellate cells (PSCs). In response to pancreatic injury, inflammation, or carcinogenic processes, PSCs undergo morphological and functional modifications to acquire a myofibroblast-like phenotype and become activated. This transition is followed by a loss of vitamin A-containing lipid droplets, an increase in alphasmooth muscle actin (αSMA) expression, and ECM secretion, such as type I collagen. It is well known that activated PSCs establish a dynamic dialogue with the PCCs, and profoundly affect the tumor cell behavior by promoting PCCs proliferation, migration, and invasion to enhance PDAC early spreading [4,9]

Objectives

Methods

Results

Discussion

Conclusion