Experimental Study On The Effect Of MicroRNA-217 On The Expression Of LC3 And Beclin-1 In PDX Model Of Giant Cell Tumor Of Bone

Objective The pathogenesis of giant cell tumor of bone(GCTB)is still unclear.Its invasiveness and high recurrence rate are the difficult problems in the treatment of this disease.A large number of studies have confirmed that LC3 and Beclin-1 play an important role in autophagy,and MicroRNA-217 may affect the progress of GCTB by regulating LC3 and Beclin-1 related genes to autophagy,but the specific mechanism of action remains to be further studied.Our team established a Patient-Derived tumor Xenograft(PDX)model to explore the association between MicroRNA-217 and GCTB,and the changes of LC3 and Beclin-1 related gene expression in subcutaneous tumors,so as to further study whether MicroRNA-217 can promote or inhibit the development of GCTB autophagy by regulating LC3 and Beclin-1 related genes.Method Human GCTB cell lines overexpressing or interfering with miR-217 were cultured in vitro and injected into the subcutaneous body of immunodeficient nude mice.Six groups of PDX models were established and the subcutaneous tumor increased naturally.During the experiment,the changes of subcutaneous tumor proliferation,volume and weight in different groups were analyzed and recorded.The expression of LC3 and Beclin-1 in subcutaneous tumor samples was detected by immunohistochemistry,quantitative PCR and Western blot,and the effect of miR-217 on the expression of LC3 and Beclin-1 in subcutaneous tumor was analyzed.All experimental data were processed by SPSS19.0statistical software package,and statistical analysis was conducted on whether the experimental group and the control group had statistical significance.Results The subcutaneous tumor growth was slower in the miR-217 mimics group than in the Control group,and faster in the miR-217 inhibitor group than in the Control group.The volume and weight of subcutaneous nodule in the miR-217 mimics group were significantly decreased,whereas the volume and weight of subcutaneous nodule in the miR-217 inhibitor group were significantly increased.The immunohistochemical results showed that the protein expression levels of LC3 and Beclin-1 in the miR-217 mimic group were significantly decreased compared with the Control group.The protein expression levels of LC3 and Beclin-1 were significantly increased in miR-217 inhibitor group.Quantitative PCR results showed that the m RNA expression levels of LC3 and Beclin-1 were significantly decreased in miR-217 mimic group compared with Control group,and the m RNA expression levels of LC3 and Beclin-1 were significantly increased in miR-217 inhibitor group.Western blot results showed that the protein expression levels of LC3 and Beclin-1 were significantly decreased in miR-217 mimic group compared with Control group.The protein expression levels of LC3 and Beclin-1were significantly increased in the miR-217 inhibitor group.Conclusions MicroRNA-217 may regulate the progression of GCTB and inhibit tumor growth through stable overexpression MicroRNA-217.Immunohistochemical results of tumor histopathological sections show that overexpression MicroRNA-217 may down-regulate the expression of autophagy-related factors LC3 and Beclin-1 in GCTB tissues,suggesting that autophagy may be reduced.These results suggest that overexpression MicroRNA-217 may downregulate autophagy-related genes LC3 and Beclin-1 and reduce the occurrence of autophagy,thus inhibiting tumor progression and proliferation.