DNA damage and repair in leukocytes of melanoma patients exposed in vitro to cisplatin

Abstract

Resistance to chemotherapeutic drugs can be an obstacle to a successful treatment of cancer patients in part associated with individual response and differences in the DNA repair system. The Comet assay is an informative test to investigate DNA damage and repair in cells in response to a variety of DNA-damaging agents, including chemotherapeutic drugs. The aim of this study was to assess leukocytes damage after in-vitro cisplatin treatment and DNA repair action using the Comet assay in 20 patients with melanoma and 20 cancer-free individuals. Leukocytes' DNA damage before and after cisplatin treatment, in three different concentrations, was analyzed. The DNA repair capability was investigated after 1-5 h of in-vitro cells growing without cisplatin. The Comet score of the patients' basal DNA damage was higher than that observed in controls, but the difference was not statistically significant (P=0.85). Although both groups had similar Comet scores to all cisplatin concentrations tested and the DNA repair times, the basal DNA damage (P<0.001) and cisplatin damages (P<0.005) were statistically lower than the different repair times investigated. Considering the progressive increase in the Comet score due to repair time, the negative results here observed could be associated with the reduced cell culture incubation that should be better evaluated. Considering the mutagenic action of cisplatin on tumor cells and the importance of individual DNA repair mechanisms in the chemotherapeutic melanoma treatment, the peripheral leukocytes could be particularly useful as a tool for DNA repair response identified by the Comet assay.

No Relationship between the Amount of DNA Damage and the Level of hMLH1 and RASSF1A Gene Expression in Bladder Cancer Cells Treated with Cisplatin and Gemcitabine

“…Cisplatin is one of the most potent antitumor agents and has the ability to induce DNA crosslinking and apoptosis, particularly in rapidly replicating cells (Wang et al, 2005;Shimabukuro et al, 2011). Similarly to other platinum compounds, cisplatin forms DNA adducts that are difficult to repair and ultimately interfere with replication and transcription, contributing to its antitumor efficacy (Kosmider et al, 2005).…”

“…After cisplatin treatment, cells were incubated with 10µM H 2 O 2 , which introduces a number of strand breaks into the DNA and allows for the identification of cross-linking damage by the assay (Blasiak et al, 1999;Heringova et al, 2006;Shimabukuro et al, 2011). Briefly, 10µl of cells was added to 100µl 0.5% low-melting-point agarose at 37ºC.…”

Genetic Instability in Normal-Appearing and Tumor Urothelium Cells and the Role of the TP53 Gene in the Toxicogenomic Effects of Antineoplastic Drugs

“…Because of its low molecular weight of 299 Da, (lower than the molecular weights of drugs commonly used in intravesical chemotherapy; e.g., mitomycin C and doxorubicin), gemcitabine is able to penetrate the bladder mucosa, which has beneficial effects on the treatment of invasive bladder cancers [60]. Cisplatin is one of the most potent antitumor agents, with the ability to induce DNA crosslinking and apoptosis [61,62]. A molecule of cisplatin consists of a central atom of platinum surrounded by two chlorine atoms and two ammonia groups.…”

Peripheral Blood Mononuclear Dna Damage Identified by the «сomet» Method, as a Possible Indicator of Sensitivity of Melanoma to Immunotherapy With Nivolumab

“…Причем процессы повреждения и репарации ДНК обнаруживаются не только на уровне соматических клеток, но и в циркулирующих в крови мононуклеарных клетках. Так, повреждение ДНК, выявленное методом Comet в культуре лейкоцитов, полученных от пациентов с меланомой, было более выраженным, чем в мононуклеарных клетках здоровых людей [6]. Возрастание уровня повреждения ДНК в лимфоцитах крови описано у первичных больных с опухолями головы и шеи [7], раком легкого [8], а при воздействии на тестируемые клетки ультрафиолетом -при раке толстой кишки и меланоме [9].…”