DNA damage induced by cis- and carboplatin as indicator for in vitro sensitivity of ovarian carcinoma cells

DNA damage induced by cis- and carboplatin in primary cells of ovarian carcinomas was determined by the alkaline comet assay. In parallel, the reduction of cell viability was measured by the fluorescein diacetate (FDA) hydrolysis assay.While in the comet assay the isolated cells showed a high degree of DNA damage after a 24 h treatment, cell viability revealed no cytotoxicity after that incubation time. The individual sensitivities to DNA damage of 12 tumour biopsies differed up to a factor of about 3. DNA damage after a one day treatment with cis- or carboplatin correlated well with the cytotoxic effects after a 7 day treatment (r = 0,942 for cisplatin r = 0.971 for carboplatin). In contrast to the platinum compounds the correlation of DNA damage and cytotoxicity induced by adriamycin was low (r = 0,692), or did not exist for gemcitabine.The measurement of DNA damage induced by cis- and carboplatin is an accurate method to determine the in vitro chemosensitivity of ovarian cancer cells towards these cytostatics, because of its quickness, sensitivity, and low cell number needed.Cis- and carboplatin used in the standard chemotherapy of ovarian carcinomas possess DNA damaging properties. The DNA damage by the platinum compounds is thought to be the main cause of their cytotoxicity [1] whereby the DNA damages result in inhibition of growth and subsequently in apoptosis and necrosis [2]. It was shown that the platinum-DNA adducts directly correlate with the disease response [3]. Therefore, the measurement of the DNA damage induced by cis- and carboplatin in ovarian carcinoma cells should reflect the sensitivity of these cells toward the platinum chemotherapeutics.DNA damage in single cells can be determined by several standard methods like measuring chromosome aberrations (CA), micronucleus test (MNT), or the comet assay. In contrast to the comet assay, the CA test and the MNT can only be used for dividing cells. Because of the low division rate of primary ovarian cance