β1 integrin mediates unresponsiveness to PI3Kα inhibition for radiochemosensitization of 3D HNSCC models

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

Abstract

Phosphoinositide 3-kinase (PI3K)-α represents a key intracellular signal transducer involved in the regulation of key cell functions such as cell survival and proliferation. Excessive activation of PI3Kα is considered one of the major determinants of cancer therapy resistance. Despite preclinical and clinical evaluation of PI3Kα inhibitors in various tumor entities, including head and neck squamous cell carcinoma (HNSCC), it remains elusive how conventional radiochemotherapy can be enhanced by concurrent PI3K inhibitors and how PI3K deactivation mechanistically exerts its effects. Here, we investigated the radiochemosensitizing potential and adaptation mechanisms of four PI3K inhibitors, Alpelisib, Copanlisib, AZD8186, and Idelalisib in eight HNSCC models grown under physiological, three-dimensional matrix conditions. We demonstrate that Alpelisib, Copanlisib and AZD8186 but not Idelalisib enhance radio- and radiochemosensitivity in the majority of HNSCC cell models (= responders) in a manner independent of PIK3CA mutation status. However, Alpelisib promotes MAPK signaling in non-responders compared to responders without profound impact on Akt, NFκB, TGFβ, JAK/STAT signaling and DNA repair. Bioinformatic analyses identified unique gene mutations associated with extracellular matrix to be more frequent in non-responder cell models than in responders. Finally, we demonstrate that targeting of the cell adhesion molecule β1 integrin on top of Alpelisib sensitizes non-responders to radiochemotherapy. Taken together, our study demonstrates the sensitizing potential of Alpelisib and other PI3K inhibitors in HNSCC models and uncovers a novel β1 integrin-dependent mechanism that may prove useful in overcoming resistance to PI3K inhibitors.

Details

Original languageEnglish
Article number116217
Number of pages13
JournalBiomedicine & pharmacotherapy
Volume171 (2024)
Early online date28 Jan 2024
Publication statusPublished - Feb 2024
Peer-reviewedYes

External IDs

ORCID /0000-0001-5684-629X/work/152546085
Scopus 85183476490
ORCID /0000-0002-2844-053X/work/153110486

Keywords

Sustainable Development Goals

Keywords

  • Phosphoinositide-3 Kinase Inhibitors/pharmacology, Squamous Cell Carcinoma of Head and Neck, Class I Phosphatidylinositol 3-Kinases, Aniline Compounds, Humans, Integrin beta1/genetics, Phosphatidylinositol 3-Kinases/metabolism, Thiazoles, Cell Line, Tumor, Head and Neck Neoplasms, Chromones

Library keywords