vx-970 and Carcinoma--Squamous-Cell

The study aimed to assess the effect of p-ATR inhibitor VE-822 in the combination chemotherapy with cisplatin of head and neck squamous cell carcinoma and to explore the possible mechanism.. The DNA damage levels were determined by comet assay and western blot experiments in cisplatin-resistant and sensitive cell lines. The IC50 value changes after combination treatment with VE-822 in cisplatin sensitive and resistant cell lines were detected by the CCK-8 test. The effects of VE-822 combined with cisplatin on proliferation ability, colony formation ability, migration ability, cell apoptosis and cell cycle changes were observed. The increased expression of the p-ATR protein was related to the DNA damage repair pathway in head and neck squamous cell carcinoma cisplatin-resistant cells. VE-822 inhibited cell proliferation, colony formation and migration abilities and improved the cisplatin chemotherapeutic effects in subcutaneous xenograft models of nude mice by inhibiting the p-ATR expression and blocking DNA damage repair pathway.. The p-ATR expression increased in head and neck squamous cell carcinoma cisplatinresistant cells. VE-822 significantly enhanced the therapeutic effect in cisplatin resistant head and neck squamous cell carcinoma by inhibiting p-ATR expression

Topics: Animals; Antineoplastic Agents; Apoptosis; Carcinoma, Squamous Cell; Cell Line, Tumor; Cisplatin; Head and Neck Neoplasms; Humans; Mice; Mice, Nude; Squamous Cell Carcinoma of Head and Neck

(1) Kinase inhibitors (KI) targeting components of the DNA damage repair pathway are a promising new type of drug. Combining them with ionizing radiation therapy (IR), which is commonly used for treatment of head and neck tumors, could improve tumor control, but could also increase negative side effects on surrounding normal tissue. (2) The effect of KI of the DDR (ATMi: AZD0156; ATRi: VE-822, dual DNA-PKi/mTORi: CC-115) in combination with IR on HPV-positive and HPV-negative HNSCC and healthy skin cells was analyzed. Cell death and cell cycle arrest were determined using flow cytometry. Additionally, clonogenic survival and migration were analyzed. (3) Studied HNSCC cell lines reacted differently to DDRi. An increase in cell death for all of the malignant cells could be observed when combining IR and KI. Healthy fibroblasts were not affected by simultaneous treatment. Migration was partially impaired. Influence on the cell cycle varied between the cell lines and inhibitors; (4) In conclusion, a combination of DDRi with IR could be feasible for patients with HNSCC. Side effects on healthy cells are expected to be limited to normal radiation-induced response. Formation of metastases could be decreased because cell migration is impaired partially. The treatment outcome for HPV-negative tumors tends to be improved by combined treatment.

Topics: Ataxia Telangiectasia Mutated Proteins; Carcinoma, Squamous Cell; Cell Death; Cell Line, Tumor; Cells, Cultured; DNA Repair; DNA-Activated Protein Kinase; Head and Neck Neoplasms; Humans; Isoxazoles; Protein Kinase Inhibitors; Pyrazines; Pyridines; Quinolines; Triazoles; X-Rays

Inducing DNA damage is known to be one of the mechanisms of cytotoxic chemotherapy agents for cancer such as cisplatin. The endogenous DNA damage response confers chemoresistance to these agents by repairing DNA damage. The initiation and transduction of the DNA damage response (DDR) signaling pathway, which is dependent on the activation of ATM (ataxia-telangiectasia mutated) and ATR (ataxia telangiectasia and Rad3-related), is essential for DNA damage repair, the maintenance of genomic stability and cell survival. Therefore, ATM or ATR inhibition is considered as a promising strategy for sensitizing cancer cells to chemotherapy. This study is aimed to explore the effect of ATR inhibitor on sensitizing ESCC (esophageal squamous cell carcinoma) cells to cisplatin, and whether ATM deficiency could impact the sensitization. We found that 21.5% of ESCC cases had ATM deficiency and that patients with ATR activation after neoadjuvant chemotherapy had worse chemotherapy response and poorer overall survival than that without ATR activation (32 mons vs. >140mons). Then, it was shown that VE-822 inhibited ATR-CHK1 pathway activation, leading to the accumulation of cisplatin-modified DNA. And it inhibited cell proliferation, induced cell cycle arrest in G1 phase and enhanced cell apoptosis. Moreover, VE-822 significantly sensitized ESCC cells to cisplatin, and these two drugs had synergistic effects, especially in ATM-deficient cells, in vitro and in vivo. Our results suggest that ATR inhibition combining with cisplatin is a new strategy for managing patients with ESCC, especially those with ATM-deficiency. However, this is an idea that requires further validation.

Topics: Animals; Antineoplastic Agents; Apoptosis; Ataxia Telangiectasia Mutated Proteins; Carcinoma, Squamous Cell; Cell Cycle; Cell Proliferation; Cisplatin; CRISPR-Cas Systems; Drug Resistance, Neoplasm; Esophageal Neoplasms; Female; Gene Expression Regulation, Neoplastic; Humans; Isoxazoles; Mice; Mice, Inbred BALB C; Mice, Nude; Prognosis; Pyrazines; Signal Transduction; Survival Rate; Tumor Cells, Cultured; Xenograft Model Antitumor Assays