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

Florian T Unger,Garri Tchartchian,Rudy L De Wilde,Hermann A Klasen,Irene Witte

doi:10.1186/1471-2407-9-359

Florian T Unger, Garri Tchartchian + Show 3 more

Open Access

https://doi.org/10.1186/1471-2407-9-359

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Abstract

BackgroundThe DNA damage by platinum cytostatics is thought to be the main cause of their cytotoxicity. Therefore the measurement of the DNA damage induced by cis- and carboplatin should reflect the sensitivity of cancer cells toward the platinum chemotherapeutics.MethodsDNA 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.ResultsWhile 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.ConclusionThe 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.

Highlights

The DNA damage by platinum cytostatics is thought to be the main cause of their cytotoxicity
Cis- and carboplatin used in the standard chemotherapy of ovarian carcinomas possess DNA damaging properties
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

Summary

Introduction

The DNA damage by platinum cytostatics is thought to be the main cause of their cytotoxicity. The measurement of the DNA damage induced by cis- and carboplatin should reflect the sensitivity of cancer cells toward the platinum chemotherapeutics. 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. Because of the low division rate of primary ovarian cancer cells in vitro the comet assay seems to be the method of choice as a rapid and highly sensitive test for the determination of DNA damages in cells of ovarian cancer biopsies. DNA crosslinks of cis- and carboplatin can be indirectly determined by introducing single strand breaks in platinum treated DNA via x-rays or strand breaking chemicals like methyl methanesulfonate (MMS) [6]. Even though the portion of interstrand crosslinks is only 1-2% of all the DNA damage induced by cis- and carboplatin [1,7] the constant ratio of the adducts allows the representative determination of all DNA damages by measuring the interstrand crosslinks only

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