Chuan Liu1, Kui Liao2, Neil Gross3, Zhihai Wang1, Guojun Li3, Wenqi Zuo1, Shixun Zhong1, Zixin Zhang4, Hua Zhang5, Jianming Yang6, Guohua Hu7. 1. Department of Otorhinolaryngology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China. 2. Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China. 3. Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, TX, USA. 4. Department of Oncology, The Affiliated Hospital of Ningxia Medical University, Ningxia, China. 5. Department of Otolaryngology-Head and Neck Surgery, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, China. Electronic address: zhang0hua@163.com. 6. Department of Otorhinolaryngology, The Second Hospital of Anhui Medical University, Hefei, China. Electronic address: jmyang88@163.com. 7. Department of Otorhinolaryngology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China. Electronic address: hghcq@sina.com.
Abstract
BACKGROUND: Radiotherapy is a central treatment option for hypopharyngeal squamous cell carcinoma, but the prognoses of patients treated with radiotherapy only are not satisfactory due to radioresistance. The underlying molecular mechanisms remain largely elusive, and mechanism-derived predictive markers of radioresistance are currently unavailable. METHODS: In this study, we first established a specifically radioresistant FaDu cell line by repeated exposure to ionizing radiation with a total dose of 60 Gy (FaDu-RR). The validation of FaDu-RR cells was performed by clonogenic cell survival assay and cell proliferation assay. Microarrays and bioinformatics were analyzed to determine the differentially expressed mRNAs and their functions. DNA-repair capabilities were tested by cell cycle analysis and comet assay. The expressions of four key proteins in homologous recombination pathways, including BRCA1, BRCA2, RPA1, and Rad51, were detected both in FaDu-RR cells and radioresistant xenograft. RESULTS: We established the specifically radioresistant FaDu cell line. Through microarrays and bioinformatics, homologous recombination pathways were suggested to play important roles in radioresistant mechanisms. High expression levels of key proteins in homologous recombination pathways were then detected both in FaDu-RR cells and radioresistant xenograft. Silencing RPA1 could reduce the radioresistance of FaDu-RR cells. CONCLUSION: Our results provided strong evidence that homologous recombination enhances the radioresistance in hypopharyngeal carcinoma. Proteins in homologous recombination pathways may be potential biomarkers to predict hypopharyngeal carcinoma response to radiotherapy, establishing a basis for their utility in clinical practice.
BACKGROUND: Radiotherapy is a central treatment option for hypopharyngeal squamous cell carcinoma, but the prognoses of patients treated with radiotherapy only are not satisfactory due to radioresistance. The underlying molecular mechanisms remain largely elusive, and mechanism-derived predictive markers of radioresistance are currently unavailable. METHODS: In this study, we first established a specifically radioresistant FaDu cell line by repeated exposure to ionizing radiation with a total dose of 60 Gy (FaDu-RR). The validation of FaDu-RR cells was performed by clonogenic cell survival assay and cell proliferation assay. Microarrays and bioinformatics were analyzed to determine the differentially expressed mRNAs and their functions. DNA-repair capabilities were tested by cell cycle analysis and comet assay. The expressions of four key proteins in homologous recombination pathways, including BRCA1, BRCA2, RPA1, and Rad51, were detected both in FaDu-RR cells and radioresistant xenograft. RESULTS: We established the specifically radioresistant FaDu cell line. Through microarrays and bioinformatics, homologous recombination pathways were suggested to play important roles in radioresistant mechanisms. High expression levels of key proteins in homologous recombination pathways were then detected both in FaDu-RR cells and radioresistant xenograft. Silencing RPA1 could reduce the radioresistance of FaDu-RR cells. CONCLUSION: Our results provided strong evidence that homologous recombination enhances the radioresistance in hypopharyngeal carcinoma. Proteins in homologous recombination pathways may be potential biomarkers to predict hypopharyngeal carcinoma response to radiotherapy, establishing a basis for their utility in clinical practice.
Authors: Angeles Carlos-Reyes; Marcos A Muñiz-Lino; Susana Romero-Garcia; César López-Camarillo; Olga N Hernández-de la Cruz Journal: Front Oncol Date: 2021-11-24 Impact factor: 6.244