Inhibition of potential lethal damage repair and related gene expression after carbon-ion beam irradiation to human lung cancer grown in nude mice

Abstract

To detect expression of DNA repair genes of the tumor clonogens after carbon-ion or X-ray irradiation in relation to early and rapid survival recovery (PLD repair) occurring after irradiation. At first, we performed colony assay after irradiation of 5Gy of carbon-ion or 9 and 12Gy of X-ray to compare time-dependent cell survival of the IA cells after each irradiation. Second, to search the genes causing PLD repair after irradiation of 5Gy of carbon-ion or 12Gy of X-ray, we evaluated gene expressions by using semi-quantitative RT-PCR on the selected 33 genes reportedly related to DNA repair. PLD repair was found only after X-ray irradiation. The RT-PCR results were as follows. In this IA cells that had point mutation of p53, gene expressions of TP53, TP53INP1 and CDKN1A were not significantly vary. We think 10 genes that show a significant difference between X-ray and carbon-ion beam exposure are candidates associated with PLD repair in this IA cells .