1. Academic Validation
  2. NRF3 suppresses squamous carcinogenesis, involving the unfolded protein response regulator HSPA5

NRF3 suppresses squamous carcinogenesis, involving the unfolded protein response regulator HSPA5

  • EMBO Mol Med. 2023 Oct 9:e17761. doi: 10.15252/emmm.202317761.
Selina Gurri 1 Beat Siegenthaler 1 Michael Cangkrama 1 Gaetana Restivo 2 Marcel Huber 3 James Saliba 4 Reinhard Dummer 2 Volker Blank 4 Daniel Hohl 3 Sabine Werner 1
Affiliations

Affiliations

  • 1 Department of Biology, Institute of Molecular Health Sciences, ETH Zurich, Zurich, Switzerland.
  • 2 Department of Dermatology, University Hospital Zurich, Zurich, Switzerland.
  • 3 Service of Dermatology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
  • 4 Lady Davis Institute for Medical Research, McGill University, Montreal, Canada.
Abstract

Epithelial skin cancers are extremely common, but the mechanisms underlying their malignant progression are still poorly defined. Here, we identify the NRF3 transcription factor as a tumor suppressor in the skin. NRF3 protein expression is strongly downregulated or even absent in invasively growing Cancer cells of patients with basal and squamous cell carcinomas (BCC and SCC). NRF3 deficiency promoted malignant conversion of chemically induced skin tumors in immunocompetent mice, clonogenic growth and migration of human SCC cells, their invasiveness in 3D cultures, and xenograft tumor formation. Mechanistically, the tumor-suppressive effect of NRF3 involves HSPA5, a key regulator of the unfolded protein response, which we identified as a potential NRF3 interactor. HSPA5 levels increased in the absence of NRF3, thereby promoting Cancer cell survival and migration. Pharmacological inhibition or knock-down of HSPA5 rescued the malignant features of NRF3-deficient SCC cells in vitro and in preclinical mouse models. Together with the strong expression of HSPA5 in NRF3-deficient Cancer cells of SCC patients, these results suggest HSPA5 inhibition as a treatment strategy for these malignancies in stratified Cancer patients.

Keywords

HSPA5; NRF3; malignancy; skin carcinogenesis; unfolded protein response.

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