PURPOSE: We examined the relationship between radiosensitivity, histone H2AX (γH2AX) phosphorylation, and apoptosis to develop a new predictive assay for radiosensitivity. MATERIALS AND METHODS: Seven human tumor cell lines, including one fibrosarcoma (HT1080), four oesophageal carcinomas (TE-9, KYSE30, KYSE150, and KYSE220), and two breast carcinomas (HCC70, and ZR75-1) were used. Cellular radiosensitivity was assessed using a standard colony-forming assay. To measure the frequency of γH2AX foci, we counted the number of foci per cell under fluorescence microscopy following immunofluorescence staining. DNA content was determined by a flow cytometric assay. To assess the frequency of apoptosis, we enumerated apoptotic cells by fluorescence microscopy 24 hours after irradiation. RESULTS: All seven cell lines showed dose (0-9 Gy)-dependent increases in the number of γH2AX foci per cell 24 h after irradiation. When both the frequency of γH2AX foci normalized by DNA content and the frequency of apoptosis were used, a better correlation was observed between the actual cell survivals and the predicted ones. CONCLUSIONS: Our study shows that the number of γH2AX foci after normalization of the DNA content and apoptotic cell frequency can be used as a new predictive assay for cell survival.
PURPOSE: We examined the relationship between radiosensitivity, histone H2AX (γH2AX) phosphorylation, and apoptosis to develop a new predictive assay for radiosensitivity. MATERIALS AND METHODS: Seven humantumor cell lines, including one fibrosarcoma (HT1080), four oesophageal carcinomas (TE-9, KYSE30, KYSE150, and KYSE220), and two breast carcinomas (HCC70, and ZR75-1) were used. Cellular radiosensitivity was assessed using a standard colony-forming assay. To measure the frequency of γH2AX foci, we counted the number of foci per cell under fluorescence microscopy following immunofluorescence staining. DNA content was determined by a flow cytometric assay. To assess the frequency of apoptosis, we enumerated apoptotic cells by fluorescence microscopy 24 hours after irradiation. RESULTS: All seven cell lines showed dose (0-9 Gy)-dependent increases in the number of γH2AX foci per cell 24 h after irradiation. When both the frequency of γH2AX foci normalized by DNA content and the frequency of apoptosis were used, a better correlation was observed between the actual cell survivals and the predicted ones. CONCLUSIONS: Our study shows that the number of γH2AX foci after normalization of the DNA content and apoptotic cell frequency can be used as a new predictive assay for cell survival.
Entities:
Keywords:
Radiosensitivity; clinical radiobiology; prediction of tumor response
Authors: Sandra M Baker-Groberg; Sophia Bornstein; Jevgenia Zilberman-Rudenko; Mark Schmidt; Garth W Tormoen; Casey Kernan; Charles R Thomas; Melissa H Wong; Kevin G Phillips; Owen J T McCarty Journal: Cell Mol Bioeng Date: 2015-05-07 Impact factor: 2.321
Authors: Mohammad Habash; Luis C Bohorquez; Elizabeth Kyriakou; Tomas Kron; Olga A Martin; Benjamin J Blyth Journal: Cancers (Basel) Date: 2017-10-27 Impact factor: 6.639