title: Effects of X-ray irradiation on the overexpression of HER-2/Erb-B2 on breast cancer cell lines.
abstract: Irradiation is the conventional treatment modality for cancer patients. However, besides its cytotoxic effects on malignant cells it might also affect the biology of surviving cells. Since overexpression of HER-2 receptors on malignant cells is a prerequisite for the therapeutic efficacy of Herceptin, it seems important to know whether previous irradiation changes their overexpression. The experiments performed in this work were aimed to determine whether X-ray irradiation of MDA-MB-361 and MDA-MB-453 breast carcinoma cell lines, besides its cytotoxic action, affects the overexpression of HER-2 protein. Determination of the cytotoxic effect of X-ray irradiation was done using trypan blue test. The breast carcinoma cell responsiveness to herceptin treatment in the presence of 10% fresh human serum (from healthy volunteer's) in the presence or absence of 25 microg/ml of herceptin, in vitro before and after cell-irradiation, was evaluated by MTT test. The degree of HER-2 overexpression was determined by immunocytochemistry, using DAKO HercepTest. Preliminary results obtained in this work showed that X-ray irradiation, besides its cytotoxic effect on malignant cells, could lead to overexpression of HER-2 receptors on (initially by immunocytochemistry, HER-2 negative) tumor cells, indicating change in biology of treated tumor cells. Further investigation in this direction will probably be helpful to elucidate this task in order to improve the selection of irradiated patients for Herceptin therapy.
authors.affiliation: Department of Experimental Oncology, Institute for Oncology and Radiology of Serbia, Belgrade, Serbia and Montenegro. juranicz@ncrc.ac.yu
authors.forename: Z D
authors.initials: ZD
authors.lastname: Juranić
authors.forename: N
authors.initials: N
authors.lastname: Borojević
authors.forename: D
authors.initials: D
authors.lastname: Jovanović
authors.forename: N
authors.initials: N
authors.lastname: Stanojević-Bakić
authors.forename: Z
authors.initials: Z
authors.lastname: Zizak
authors.forename: Z
authors.initials: Z
authors.lastname: Nesković-Konstantinović
authors.forename: M
authors.initials: M
authors.lastname: Sarić
authors.forename: T
authors.initials: T
authors.lastname: Stanojković
authors.forename: T
authors.initials: T
authors.lastname: Raonić
authors.forename: D
authors.initials: D
authors.lastname: Milosević
mesh_terms: D000911:Antibodies, Monoclonal / Q000378:metabolism / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D001943:Breast Neoplasms / Q000378:metabolism* / Q000532:radiotherapy*; D045744:Cell Line, Tumor; D004396:Coloring Agents / Q000494:pharmacology; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D009362:Neoplasm Metastasis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D013778:Tetrazolium Salts / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology; D013997:Time Factors; D000068878:Trastuzumab; D014343:Trypan Blue / Q000494:pharmacology; D014965:X-Rays
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D004396:Coloring Agents; D018719:Erb-b2 Receptor Tyrosine Kinases; D013778:Tetrazolium Salts; D013844:Thiazoles; D000068878:Trastuzumab; D014343:Trypan Blue; C022616:thiazolyl blue