Background: The effects of radiation on the cellular compartments of the tumor microenvironment (TME) might be essential in radiotherapy outcomes.
Objective: We aimed to assess the effects of the different doses of gamma irradiation on viability, ABCA1 and MMP-9 expression in adipose-derived mesenchymal stem cells (ASCs) as a critical part of TME.
Material and Methods: In this experimental study, ASCs were extracted from five healthy donors and irradiated with different doses of 5, 10 and 30 Gy of gamma. Then, RNA was extracted from irradiated ASCs and cDNA was synthesized. The viability of ASCs was determined at 24, 48, 72 and 168 h after irradiation using trypan blue staining. The expression of ABCA1 was checked by quantitative real-time (qRT)-PCR technique and the expression of MMP-9 protein was evaluated by western-blot.
Results: Based on our findings, 10 Gy and 30 Gy but not 5 Gy of gamma irradiation significantly decreased the viability of ASCs after 24, 48, 72 and 168 h compared to the non-irradiated cells (P< 0.05). However, a dose of 5 Gy increased ABCA1 in ASCs significantly compared to 10 Gy and 30 Gy (P=0.01 and P=0.02, respectively). In addition, the analysis of western blot data showed that 5 Gy of gamma irradiation significantly increased the expression of MMP-9 in ASCs (P=0.019).
Conclusion: It is concluded that various doses of gamma radiation elicit differential ASCs responses that may lead to different tumor cell reactions to the radiotherapy through bystander effects.