Objective To investigate the role and primary mechanism of a novel fusion gene RELCH-RET in driving the malignant transformation of normal human bronchial epithelial(HBE)cells.Methods Based on retrospective clinical data from 456 non-small cell lung cancer(NSCLC)patients admitted in the Second Affiliated Hospital of Army Medical University from January 2019 to June 2022,a fusion gene,RELCH-RET,was identified as a research target.Three cell models were established:negative control(HBE VC,transfected with empty lentiviral vector),RET control(HBE RET,transfected with lentiviral overexpression vector of Flag-RET),and experimental group(HBE RELCH-RET,transfected with lentiviral overexpression vector of Flag-RELCH-RET).MTS assay and Transwell assay were used to detect cell proliferation and migratory and invasive abilities.In vivo tumorigenicity of the 3 cell models was assessed in 15 female non-obese diabetic/severe combined immunodeficiency(NOD/SCID)mice(SPF grade,4 weeks old,weighing 15.1±0.4 g)via subcutaneous xenograft experiments,with 5 animals in each group.Western blotting was employed to detect the autophosphorylation of RET(Y905)and the phosphorylation of downstream signaling proteins ERK1/2,EGFR(Y845)and STAT3(Y705).Dimerization and multimerization status of RELCH-RET were analyzed by chemical cross-linking(DTME treatment)in combination with Western blotting,with the reversibility being confirmed through de-cross-linking experiments.Results There were 3 cases carrying RELCH-RET fusion gene screened out from the 469 NSCLC patients.Compared with the HBE VC and HBE RET groups,the HBE RELCH-RET group exhibited significantly enhanced cell proliferation(P<0.01),and acquired migratory and invasive abilities(P<0.01),while the control groups did not demonstrate the abilities.In the mouse xenograft tumor model,HBE cells stably expressing RELCH-RET developed significant tumor nodules(P<0.001),whereas the control groups(empty vector and wild-type RET)failed to exhibit detectable tumor growth.Western blotting revealed that RELCH-RET could induce the autophosphorylation of the RET tyrosine residue(Y905)and significantly up-regulate the phosphorylation levels of ERK1/2,EGFR(Y845),and STAT3(Y705)proteins.Chemical cross-linking combined with Western blot analysis demonstrated that RELCH-RET formed a dimer(～170 kDa)in HBE cells,which is reversibly dissociated into monomers upon decross-linking treatment.Conclusion The novel fusion gene RELCH-RET,promotes ligand-independent dimerization/oligomerization,thereby mediating RET autophosphorylation,subsequently activates the downstream typical RET signaling pathway and ultimately drives the malignant transformation of normal HBE cells.

BACKGROUND: Related studies have shown that extracorporeal shock wave therapy has a positive effect on the treatment of knee osteoarthritis, but its effectiveness in treating knee osteoarthritis is not very clear, and the final results of various related studies are not same. OBJECTIVE: To analyze the efficacy of extracorporeal shock wave therapy for knee osteoarthritis using meta-analysis. METHODS: Chinese and English databases were searched in detail from inception to December 2019. The inclusion criteria were developed based on the Prisma principle to screen the randomized controlled trial of extracorporeal shock wave therapy for knee osteoarthritis. The treatment method of the experimental group was extracorporeal shock wave therapy or extracorporeal shock wave therapy combined with drugs and arthroscopic debridement. The treatment method of the control group was one of drug treatment, ultrasound treatment, laser treatment, exercise therapy, arthroscopy or blank control. The quality of the included literature was evaluated according to the Cochrane Handbook 5.1 bias risk assessment tool. Relevant data were analyzed using RevMan v5.3 software. RESULTS AND CONCLUSION: (1) A total of 21 randomized controlled trials were included, with a total of 1 736 patients with knee osteoarthritis, including 895 in the experimental group and 841 in the control group. (2) Meta-analysis shows that the visual analogue scale score of the experimental group was lower than that of the control group [SMD=-1.18, 95%CI(-1.42,-0.95), Z=9.75, P <0.000 01]. Joint motion range was greater in the experimental group than in the control group [SMD=-1.69, 95%CI(-2.01,-1.36), Z=10.16, P <0.000 01]. WOMAC score was lower in the experimental group than in the control group [SMD=-9.66, 95%CI(-13.12,-6.20), Z=5.47, P < 0.000 01]. (3) The results show that extracorporeal shock wave therapy for knee osteoarthritis has a certain positive effect on pain relief and joint motion range. However, the number of cases included in this study is small, and subsequent large-scale multi-center studies are needed to further clarify the relevant utility.