(5-(2-4-bis((3s)-3-methylmorpholin-4-yl)pyrido(2-3-d)pyrimidin-7-yl)-2-methoxyphenyl)methanol and Head-and-Neck-Neoplasms

The EGFR pathway plays a critical role in head and neck squamous cell carcinoma (HNSCC). Targeted therapies against the EGFR are utilized as a treatment for HNSCCC. However, patient response is heterogeneous and molecular biomarkers are lacking to predict patient response. Therefore, functional assays where drug response is directly evaluated in tumor cells are an interesting alternative. Previous studies have shown that experimental conditions modify the drug response observed in functional assays. Thus, in this work the influence of the culture environment on response to Cetuximab (EGFR monoclonal antibody) and AZD8055 (mTOR inhibitor) was evaluated. HNSCC UM-SCC-1 and UM-SCC-47 cells were cultured in 2D monoculture and compared with: 2D co-culture with cancer-associated fibroblasts (CAF); 3D culture in collagen hydrogels; and 3D culture in tumor spheroids. The results showed UM-SCC-1 drug response significantly changed in the different culture environments; leading to an increase in drug resistance in the CAF co-culture and the 3D spheroids. Conversely, UM-SCC-47 exhibited a more constant drug response across culture conditions. In conclusion, this work highlights the importance of culture conditions that modulate response to EGFR pathway inhibition.

Topics: Cell Culture Techniques; Cell Line, Tumor; Cetuximab; Drug Screening Assays, Antitumor; ErbB Receptors; Female; Head and Neck Neoplasms; Humans; Male; Morpholines; Neoplasm Proteins; Signal Transduction; Spheroids, Cellular; Squamous Cell Carcinoma of Head and Neck

Head and neck squamous cell carcinomas (HNSCC) are frequently altered along the PI3K/AKT/mTORC signaling axis. Despite excellent preclinical data, the use of compounds targeting this pathway as monotherapy has been underwhelming in initial clinical trials, and identification of predictive biomarkers remains challenging. To investigate mTORC-specific inhibition, we tested catalytic mTORC (AZD8055) and PI3K/mTORC (NVP-BEZ-235) inhibitors ± cetuximab in a panel of HNSCC cell lines and patient-derived xenografts (PDX). Cell lines were assayed for response to all agents and siRNA knockdown of targets by multiple approaches. All cell lines showed similar response to both drug and siRNA inhibition of both PI3K and mTORC pathways, with anti-EGFR combination producing modest additive effect. Five PDX models that presented PIK3CA mutation or intrinsic cetuximab resistance were treated with a combination of cetuximab and AZD8055.

Topics: Animals; Carcinoma, Squamous Cell; Cell Line, Tumor; Cetuximab; Class I Phosphatidylinositol 3-Kinases; Combined Modality Therapy; Drug Resistance, Neoplasm; ErbB Receptors; Head and Neck Neoplasms; Humans; Mechanistic Target of Rapamycin Complex 1; Mice; Molecular Targeted Therapy; Morpholines; Signal Transduction; Squamous Cell Carcinoma of Head and Neck; Xenograft Model Antitumor Assays

The serine/threonine kinase mammalian target of rapamycin (mTOR) promotes cell survival and proliferation, and is constitutively activated in head and neck squamous cell carcinoma (HNSCC). Thus mTOR is an important target for drug development in this disease. Here we tested the anti-tumor ability of AZD8055, the novel mTOR inhibitor, in HNSCC cells. AZD8055 induced dramatic cell death of HNSCC lines (Hep-2 and SCC-9) through autophagy. AZD8055 blocked both mTOR complex (mTORC) 1 and mTORC2 activation without affecting Erk in cultured HNSCC cells. Meanwhile, AZD8055 induced significant c-Jun N-terminal kinase (JNK) activation, which was also required for cancer cell death. JNK inhibition by its inhibitors (SP 600125 and JNK-IN-8), or by RNA interference (RNAi) alleviated AZD8055-induced cell death. Finally, AZD8055 markedly increased the survival of Hep-2 transplanted mice through a significant reduction of tumor growth, without apparent toxicity, and its anti-tumor ability was more potent than rapamycin. Meanwhile, AZD8055 administration activated JNK while blocking mTORC1/2 in Hep-2 tumor engrafts. Our current results strongly suggest that AZD8055 may be further investigated for HNSCC treatment in clinical trials.

Topics: Animals; Carcinoma, Squamous Cell; Cell Line, Tumor; Female; Head and Neck Neoplasms; HEK293 Cells; Humans; MAP Kinase Kinase 4; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Mice; Mice, Inbred BALB C; Morpholines; Multiprotein Complexes; Protein Kinase Inhibitors; RNA Interference; Squamous Cell Carcinoma of Head and Neck; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays