Low dose radiation-induced adaptive response preventing HPRT mutation is Fhit independent

Purpose: To study whether fragile histidine triad (Fhit) prevents IR-induced hypoxanthineguanine phosphoribosyltransferase (HPRT) mutation and whether Fhit plays any role in preventing HPRT mutation through low dose-induced adaptive response. Materials and methods: Establishing human cell lines with or without Fhit expression by making constructs expressing hemagglutinin (HA) alone or HA-Fhit fusion protein and transfecting the vector to HeLa cells. The effects of Fhit on ionising radiation (IR)-induced mutation were examined by observing HPRT mutation rates in the established cell lines following different doses of IR. The role of Fhit on low dose IR-induced adaptive response were examined by observing HPRT mutation rates in the established cell lines that were exposed to 0.1 Gy and followed with high dose IR or ultraviolet (UV) exposure. Results: Low dose (0.1 Gy) does not affect HPRT mutation rates in these cell lines. Fhit prevents high dose IR (≥2 Gy)-induced mutation as it prevents UV-induced mutation. However, low dose of IR (0.1 Gy)-induced adaptive response prevents both high doses of IR and UV-induced mutation in both the cells with and without Fhit expression. Conclusions: Fhit prevents IR-induced HPRT mutation and preventing mutation through low dose of IR-induced adaptive response is Fhit independent.