2. Academic Validation
  3. MicroRNA-mediated PTEN downregulation as a novel non-genetic mechanism of acquired resistance to PI3Kα inhibitors of head & neck squamous cell carcinoma

MicroRNA-mediated PTEN downregulation as a novel non-genetic mechanism of acquired resistance to PI3Kα inhibitors of head & neck squamous cell carcinoma

  • Drug Resist Updat. 2025 Jul:81:101251. doi: 10.1016/j.drup.2025.101251.
Claudio Pulito 1,  Sebastiano Vaccarella 1,  Alina Catalina Palcau 2,  Federica Ganci 1,  Renata Brandi 1,  Carlotta Frascolla 1,  Andrea Sacconi 3,  Valeria Canu 1,  Anna Benedetti 1,  Valentina De Pascale 1,  Sara Donzelli 1,  Anne-Sophie Fisch 4,  Valentina Manciocco 5,  Renato Covello 6,  Fulvia Pimpinelli 2,  Aldo Morrone 7,  Francesco Fazi 8,  Raul Pellini 5,  Paola Muti 9,  Jalna Meens 10,  Christina Karamboulas 10,  Anthony C Nichols 11,  Sabrina Strano 12,  Konrad Klinghammer 13,  Ingeborg Tinhofer 14,  Laurie Ailles 10,  Giulia Fontemaggi 15,  Giovanni Blandino 16
Affiliations

Affiliations

  • 1 Translational Oncology Research Unit, IRCCS Regina Elena National Cancer Institute, Rome 00144, Italy.
  • 2 Microbiology and Virology Unit, San Gallicano Dermatological Institute IRCSS, Rome 00144, Italy.
  • 3 UOSD Clinical Trial Center, Biostatistics and Bioinformatics, IRCCS Regina Elena National Cancer Institute, Rome 00144, Italy.
  • 4 Department of Radiooncology and Radiotherapy, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany.
  • 5 Department of Otorhinolaryngology, IRCCS Regina Elena National Cancer Institute, Rome 00144, Italy.
  • 6 Department of Pathology, IRCCS Regina Elena National Cancer Institute, Rome 00144, Italy.
  • 7 Scientific Director Office, IRCCS San Gallicano Dermatology Institute, Rome 00144, Italy.
  • 8 Department of Anatomical, Histological, Forensic & Orthopedic Sciences, Section of Histology & Medical Embryology, Sapienza University of Rome, Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Rome, Italy.
  • 9 Department of Biomedical, Surgical and Dental Sciences, University of Milan La Statale, Milan 20122, Italy.
  • 10 Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.
  • 11 Department of Otolaryngology - Head and Neck Surgery, Western University, London, Ontario, Canada.
  • 12 SAFU Unit, IRCCS Regina Elena National Cancer Institute, Rome 00144, Italy.
  • 13 Department of Hematology, Oncology and Cancer Immunology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; German Cancer Consortium (DKTK) and German Cancer Research Center (DKFZ), Heidelberg, Germany.
  • 14 Department of Radiooncology and Radiotherapy, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany; German Cancer Consortium (DKTK) and German Cancer Research Center (DKFZ), Heidelberg, Germany.
  • 15 Translational Oncology Research Unit, IRCCS Regina Elena National Cancer Institute, Rome 00144, Italy. Electronic address: giulia.fontemaggi@ifo.it.
  • 16 Translational Oncology Research Unit, IRCCS Regina Elena National Cancer Institute, Rome 00144, Italy. Electronic address: giovanni.blandino@ifo.it.
PMID: 40382983 DOI: 10.1016/j.drup.2025.101251
Abstract

Aims: Head and neck squamous cell carcinomas (HNSCCs) frequently harbor alterations in the PI3K signalling axis and, particularly, in the PIK3CA gene. The promising rationale of using PI3K inhibitors for the treatment of HNSCC has, however, clashed with the spontaneous development of resistance over time.

Methods: To identify valuable targets for overcoming acquired resistance to PI3Kα inhibitors in HNSCC, we performed MicroRNA profiling on a cohort of HNSCC PDXs that were treated with alpelisib, including both responsive and resistant tumors. Using CRISPR/Cas9, siRNA, and PTEN-/- isogenic and alpelisib-resistant cell models, we examined the role of PTEN in resistance acquisition. Phospho-proteomic analysis identified PTEN-dependent phosphorylation events, while PI3Kα inhibitor-resistant organoids were used to assess PLK1 Inhibitor efficacy.

Results: We identified MicroRNAs altered in resistant PDXs, including members of the miR-17-92 cluster. Mechanistically, we observed that the hyperactive c-Myc was recruited to MIR17HG regulatory regions in alpelisib-resistant cells, sustaining miR-17-5p, miR-19b-3p, and miR-20a-5p expression, which downregulated PTEN. PTEN knockout or depletion conferred alpelisib resistance in HNSCC cells. We identified PTEN-dependent phosphorylation events, such as p-PLK1-T210, involved in resistance. Interestingly, pharmacological inhibition of PLK1 strongly reduced the viability of PI3Kα-resistant organoids derived from HNSCC PDXs and cell line models.

Conclusion: Overall, this study unveils a novel, microRNA-driven, non-genetic mechanism contributing to acquired resistance to PI3Kα inhibitors in HNSCC. Indeed, linking hyperactive c-Myc to sustain miR-17-92 expression and consequent PTEN downregulation, we also propose that targeting PTEN-dependent downstream effectors, such as PLK1, may offer a powerful therapeutic strategy for resistant HNSCC.

Keywords

HNSCC; PIK3CA inhibitor; PLK1 inhibitor; PTEN; drug-resistance; microRNA.

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