Objective Intercellular communication within pancreatic ductal adenocarcinoma (PDAC) dramatically contributes to metastatic processes. The underlying mechanisms are poorly understood, resulting in a lack of targeted therapy to counteract stromal-induced cancer cell aggressiveness. Here, we investigated whether ion channels, which remain understudied in cancer biology, contribute to intercellular communication in PDAC.
Design We evaluated the effects of conditioned media from patient-derived cancer-associated fibroblasts (CAFs) on electrical features of pancreatic cancer cells (PCC). The molecular mechanisms were deciphered using a combination of electrophysiology, bioinformatics, molecular and biochemistry techniques in cell lines and human samples. An orthotropic mouse model where CAF and PCC were co-injected was used to evaluate tumour growth and metastasis dissemination. Pharmacological studies were carried out in the Pdx1-Cre, Ink4afl/fl LSL-KrasG12D (KICpdx1) mouse model.
Results We report that the K+ channel SK2 expressed in PCC is stimulated by CAF-secreted cues (8.84 vs 2.49 pA/pF) promoting the phosphorylation of the channel through an integrin–epidermal growth factor receptor (EGFR)–AKT (Protein kinase B) axis. SK2 stimulation sets a positive feedback on the signalling pathway, increasing invasiveness in vitro (threefold) and metastasis formation in vivo. The CAF-dependent formation of the signalling hub associating SK2 and AKT requires the sigma-1 receptor chaperone. The pharmacological targeting of Sig-1R abolished CAF-induced activation of SK2, reduced tumour progression and extended the overall survival in mice (11.7 weeks vs 9.5 weeks).
Conclusion We establish a new paradigm in which an ion channel shifts the activation level of a signalling pathway in response to stromal cues, opening a new therapeutic window targeting the formation of ion channel-dependent signalling hubs.
- ION CHANNELS
- PANCREATIC CANCER
- CELL SIGNALLING
- EPIDERMAL GROWTH FACTOR
Data availability statement
Data are available in a public, open access repository.
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JN and CB contributed equally.
RT and OS contributed equally.
Contributors RR-M, CBérenguier, BA, BL and OS performed patch clamp experiments and statistical analysis. RR-M, CBérenguier, BA, SST, BP and HG performed in vitro experiments, WB and related statistical analysis. SST, GE and ZH performed flow cytometry experiments and data analysis. SST, JN and RT performed in vivo experiments and related IHC and statistical analysis. FB established pancreatic ductal adenocarcinoma cell lines silences for SK2 or sigma-1 receptor and performed all proximity ligation assay experiments. PF, FB and ND performed in silico analysis. PM synthesised and provided 1(S) ligand. CBousquet provided the proteomic analysis of cancer-associated fibroblasts' secretum. RR-M, RT and OS conceived, designed, supervised, analysed and interpreted the study and provided critical review. OS is responsible for the overall content as guarantor.
Funding The work described in this paper was supported by grants from the Fondation de France (RT: 00087538; OS: 00038330 and 00059283), the French National Institute of Cancer (RT: INCA, PLBio13-134), La Ligue contre le Cancer (RR-M: GB/MA/IQ-10607 and GB/MA/CD/IQ-12187), Foundation ARC (RT: PJA20191209372; OS: PJA 2016 120 4740 and PJA 2019 120 9546; RR-M: PJA 2018 207701) and the Agence Nationale pour la Recherche (HG: ANR19-14-0049-01). JN was supported by Ministère de la Recherche and by Ligue contre le Cancer. CB was supported by the Fondation pour la Recherche Medicale. ST was supported by the French National Institute of Cancer (INCA, Pancreas 2017). BA was supported by the Ministère de la Recherche, de l’Enseignement Supérieur et de l’Innovation.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer reviewed.
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