Visit our Expo - Redox and Inflammation signaling 2012

Session XVII : Cell signaling in health and disease Poster XVII, 41
Inactivation of human melanoma cells induced by alkylating agents and/or highly
ionizing radiation
Aleksandra M. Risti'-Fira1, Ivan M. Petrovi'1, Lela B. Kori'anac1, Danijela V.
Todorovi'1, Lucia M. Valastro2, Giacomo Cuttone2, Giuseppe Privitera3
1 Vin(a Institute of Nuclear Sciences, Belgrade, Serbia and Montenegro
2 Istituto Nazionale di Fisica Nucleare, LNS, Catania, Italy
3 Institute of Radiology and Radiation Oncology, University of Catania, Italy
E-mail: aristic@vin.bg.ac.yu
The response of human HTB140 melanoma cells to chemotherapeutic drugs fotemustine
(FM) and dacarbazine (DTIC) as well as of proton irradiation were studied. Viability of cells
treated with 100 and 250 micromolar drugs was assessed after incubation of 6, 24, 48, 72 and
96 h. Proton irradiations of exponentially growing cells were performed at the CATANA
(Centro di Adro Terapia e Applicazzioni Nucleari Avanzati) facility for treatment of eye
melanoma at INFN, LNS – Catania, delivering to the cell monolayer single doses of 2, 4, 8,
12 and 16 Gy. Cell viability was evaluated 7 days after irradiation. For all treatments,
inactivation level was estimated using microtetrasolium (MTT) and sulforhodamine B (SRB)
assays. The combined effects of each drug and protons, were carried out using the same drug
concentrations, while proton doses applyed were those used in therapy, i.e. 12 and 16 Gy. In
this case viability was estimated using only SRB staining since it was shown to be more
reliable than MTT assay for the incubation of 48 h. With the increase of the drug
concentration or irradiation dose, the level of cell inactivation was more pronounced, reaching
approximately 60 %, 48 h after drug treatment or 7 days after irradiation at 16 Gy.
Considering the rate of drug concentrations used, as well as the level of doses applied, it
appears that HTB140 cells are more resistant to proton irradiation than to alkylating agents
tested. The combined treatment with FM or DTIC and protons did not show significant
changes of cell viability as compared to the effects of single agents. Slightly better cell
inactivation was obtained for 250 micromolar DTIC combined with 16 Gy proton irradiation.
Taking into account the fact that the chosen time point for measuring cumulative effects of
drug and irradiation was 48 h post-irradiation, it seams that the obtained level of viability
could be attributed almost only to the effects of drugs.
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