Objective: To investigate the effects of damage-regulated autophagy modulator (DRAM) on radiosensitivity and the related mechanisms of implanted tumors of SGC7901 human gastric carcinoma cells in nude mice.
Methods: Nude mice were randomly divided into model control group, radiotherapy group, and DRAM treatment group and radiotherapy combined with DRAM treatment group. When volume of transplantation tumor were 1.0 cm(3), radiotherapy, DRAM treatment was given. On days 3, 6 and 9 after treatment, the inhibition rate of tumor growth, pathological changes in tumor specimens, expression levels of P53, proliferating cell nuclear antigen(PCNA), C-myc, Fas-L, as well as apoptosis indexes in tumor samples were observed.
Results: Inhibition rates of tumor in DRAM combined with radiotherapy were 9.3%, 14.1%, 16.7% on day 3, 6 and 9, respectively, all significantly higher than those in the radiotherapy group(5.0%, 8.8%, 6.5%, P<0.05). The expressions of PCNA and C-myc protein were down-regulated, while the expressions of P53 and Fas-L were upregulated.
Conclusion: Damage-regulated autophagy modulator gene may promote cell apoptosis and inhibit cell growth to enhance the radiosensitivity of transplanted gastric tumor in vivo in nude mice.