Abstract 6397: Focal adhesion kinase (FAK) inhibition overcomes cisplatin resistance in head and neck squamous cell carcinoma (HNSCC)
Authors: Mohanty Atish , Pharaon Rebecca , Nam Arin , Yin Holly , Chang Sue , Guo Linlin , Pillai Raju , Kulkarni Prakash , Salgia Ravi , Massarelli Erminia 
Published: September 2020

Introduction: FAK is a non-receptor tyrosine kinase activated in response to interactions between transmembrane integrins and extracellular matrix involved in the activation of the PI3K–Akt pathway, required for cell proliferation and survival. Amplification of chromosome region 8q23-24, encoding FAK, is significantly associated with smoking, higher grade of dysplasia and progression from premalignant lesions to HNSCC. Multimodality treatment (surgery, radiation and platinum-based chemotherapy) is standard for locally advanced HNSCC. Local relapse/distant metastasis develop in 25-40% of patients with occurrence of platinum resistance. We hypothesize that FAK inhibition overcomes platinum resistance and immunosuppression in HNSCC.

Methods: RNA was extracted from normal and cancer tissue of 12 retrospectively surgically collected formalin-fixed paraffin-embedded HNSCC samples and analyzed by NanoString PanCancer Pathway and Immune Profiling panels. 93VU and SCC1 cell lines were used and cell-derived spheroids were generated on attachment plates. Cell proliferation, wound healing and apoptosis were measured by IncuCyte S3 Live-Cell Analysis System (Essen BioScience). Cells were treated with the following commercially available FAK small molecule inhibitors: NVP-TAE-226 (Novartis); PF-573228, PF-562271, PF-431396 (Pfizer); GSK2256098 (GlaxoSmithKline); VS-6063 (Verastem). FAK expression was measured by western blotting and qPCR analysis.

Results: In The Cancer Genome Atlas (TCGA) HNSCC dataset, FAK RNA expression was significantly higher in stage IV compared to stage I–III cancers (p&lt;0.001). Among the genes significantly overexpressed (&gt;2-fold change) in the 12 HNSCC samples analyzed by Nanostring pathway and immune profile panels, 17 were involved in PI3K-Akt signaling activation and 15 of these were also involved in the anchorage-dependent cell proliferation and FAK activation including the alpha form of integrins (ITGA2, ITGA6, ITGA3), the beta form of integrins (ITGB4, ITGB6), collagens (COL5A2, COL1A1, COL27A1, COL4A6, COL11A1), and laminins (LAMA3, LAMB3, LAMC2). We screened and identified that the 93VU and SCC1 cell lines were tolerant to cisplatin up to a dose of 10 uM. TAE-226 was the most effective FAK inhibitor in significantly blocking cell proliferation and wound healing in 93VU and SCC1 cell lines. TAE-226 treatment also effectively inhibited spheroid growth and proliferation in 3D culture. FAK inhibition decreased expression of chemokines and cytokines known to promote immunosuppression and metastasis such as CSF3, CXCL1, CXCL2, IL8, GPI, LIF, and CCL1.

Conclusion: Our data suggests that FAK expression is associated with higher cancer stage. Its inhibition might have a role in overcoming cisplatin resistance and in affecting immunosuppressive signals in HNSCC. Immunocompetent syngeneic HNSCC animal models are currently ongoing.

Citation Format: Atish Mohanty, Rebecca Pharaon, Arin Nam, Holly Yin, Sue Chang, Linlin Guo, Raju Pillai, Prakash Kulkarni, Ravi Salgia, Erminia Massarelli. Focal adhesion kinase (FAK) inhibition overcomes cisplatin resistance in head and neck squamous cell carcinoma (HNSCC) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6397.