A Study Of Using γH2AX In Guidance Of Individual Therapy Sensitivity For Pulmonary Carcinoma Patients

Purpose:To examinine the expression ofγH2AX in the pulmonary cancer cells and autologous peripheral blood lymphocytes after be treated with different chemotherapy drugs and X rays. And to determine whetherγH2AX could be a potential biomarker for prediction of chemosensitivity and radiosensitivity for the pulmonary carcinoma patient.Methods:1.Cells CultivationA representative sample from the tumor excision from the pulmonary carcinoma patient was immediately minced to be cell suspension under sterile conditions and incubated at 37℃in a humidified 5% CO2. Meanwhile, the autologous lymphocytes were extracted from the blood samples taken from the antecubital vein, and then were incubated with complete RPMI 1640 medium supplemented with phytohemagglutinin.Tumor cells were identified by immunocytochemical staining of anti-Cytokeratin (broad spectrum) antibody.2. Treatment to cells with chemotherapeutical drugs and X-ray irradiation2.1 Process of chemotherapeutical drugs treatment:The cancer cells and lymphocytes were exposed isochronously to Cisplatin(DDP), Carboplatin (CBP), Gemcitabine (GEM) and Adriamycin(ADM) of different concentrations respectively, and then were cultured 4 hours.2.2 Process of X-ray irradiation treatment:The cancer cells and lymphocytes were exposed to different doses of X-rays respectively.3.γH2AX expression detection: TheγH2AX expression of pulmonary carcinoma cells and lymphocytes were respectively measured by flow cytometry and immunocytochemistry. Cell proliferation was measured by MTT assay. The correlation betweenγH2AX expression and inhibitory rate of cell proliferation were analyzed.Results:1. The expression ofγH2AX increased in a concentration-dependent manner in cancer cells treated with chemotherapeuticaldrugs.This positive relationship appeared regardless of which drug use.There was also a positive correlation betweenγH2AX expressoin and cell mortality.In other words, the higherγH2AX level appeared to be associated with more cell death.2. The expression ofγH2AX increased linearly in a dose-dependent manner in cancer cells treated with X-rays. The level ofγH2AX was positively correlated with cell mortality, which means the higher expression ofγH2AX was, the higher cell mortality was.3. For lymphocytes treated with chemotherapeutical drugs and X-rays, neitherγH2AX levels nor the lymphocytes mortality was correlation with drug concentration and irradiation doses. There was also no relationship betweenγH2AX levels and lymphocytes mortality.Conclusions:There was a positive correlation between the expression ofγH2AX and cell mortality of pulmonary tumor cells. These data demonstrateγH2AX of tumor cells could be a potentially useful biomarker for monitoring chemosensitivity and radiosensitivity. OtherwiseγH2AX of lymphocytes could not monitor chemosensitivity and radiosensitivity.