Saeid Afshar1, Rezvan Najafi1, Abdolazim Sedighi Pashaki2, Mohammadreza Sharifi3, Safoora Nikzad4, Mohammad Hadi Gholami2, Alireza Khoshghadam2, Razieh Amini1, Jamshid Karimi5, Massoud Saidijam6. 1. Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran. 2. Mahdieh Radiotherapy and Brachytherapy charitable center, Hamadan, Iran. 3. Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. 4. Department of Medical Physics, Hamadan University of Medical Sciences, Hamadan, Iran. 5. Department of Biochemistry and Nutrition, Hamadan University of Medical Sciences, Hamadan, Iran. 6. Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran. Electronic address: sjam110@yahoo.com.
Abstract
OBJECTIVE: Radioresistance is a significant obstacle for effective treatment of colorectal cancer (CRC). Recent studies have indicated that miR-185 inhibits proliferation, survival, and invasion of CRC; however, the role of this miRNA in radioresistance of CRC has not been identified yet. The aim of this study is to investigate the role of miR-185 in radiosensitivity of CRC. METHODS: After transfecting the cells with mimic miR-185, expressions of IGF1R and IGF2 were evaluated by real-time PCR and western blot. The radiation response of transfected cells was also examined by colony forming assay. Sub-G1 fraction analysis through flow cytometry and caspase 3 activity was used to evaluate apoptosis. RESULTS: The results of real-time PCR and western blot indicated that IGF1R and IGF2 are downregulated in the transfected cells. Colony forming assay revealed that transfected cells were more radiosensitive than other cells. On the other hand,following irradiation the rate of apoptosis was significantly higher in the transfected cells than in the other cells. CONCLUSION: In summary, our study is the first to show that upregulation of miR-185 enhances the sensitivity of CRC cells to ionizing radiation. miR-185 may act as a novel biomarker of radioresistance and may clinically enhance the radiation response of CRC.
OBJECTIVE: Radioresistance is a significant obstacle for effective treatment of colorectal cancer (CRC). Recent studies have indicated that miR-185 inhibits proliferation, survival, and invasion of CRC; however, the role of this miRNA in radioresistance of CRC has not been identified yet. The aim of this study is to investigate the role of miR-185 in radiosensitivity of CRC. METHODS: After transfecting the cells with mimic miR-185, expressions of IGF1R and IGF2 were evaluated by real-time PCR and western blot. The radiation response of transfected cells was also examined by colony forming assay. Sub-G1 fraction analysis through flow cytometry and caspase 3 activity was used to evaluate apoptosis. RESULTS: The results of real-time PCR and western blot indicated that IGF1R and IGF2 are downregulated in the transfected cells. Colony forming assay revealed that transfected cells were more radiosensitive than other cells. On the other hand,following irradiation the rate of apoptosis was significantly higher in the transfected cells than in the other cells. CONCLUSION: In summary, our study is the first to show that upregulation of miR-185 enhances the sensitivity of CRC cells to ionizing radiation. miR-185 may act as a novel biomarker of radioresistance and may clinically enhance the radiation response of CRC.