In gastric cancer (GC), tumor cell metastasis to lymph node may occur, and can be impacted by synaptojanin 2 (SYNJ2). Herein, we explored the mechanism of SYNJ2 in the progress of GC. SYNJ2 level in GC tissues was predicted by GEPIA database. After GC cells were transfected with short hairpin RNA against SYNJ2 (shSYNJ2), shGRB2, SYNJ2 overexpression plasmid and growth factor receptor-bound protein 2 (GRB2) overexpression plasmid, the mRNA levels of SYNJ2 and GRB2 in GC cells were quantified by qRT-PCR. CCK-8, flow cytometry, wound healing, transwell and tube formation assays were performed for detecting viability, apoptosis, migration, invasion and angiogenesis of GC cells. Protein levels of GRB2, vascular endothelial growth factor (VEGF), E-Cadherin, N-Cadherin and Vimentin in GC cells were measured by Western blot. The relationship between SYNJ2 and GRB2 was assessed by Co-immunoprecipitation (CO-IP) assay. SYNJ2 was highly expressed in GC tissues and cells. SYNJ2 overexpression promoted viability, migration, invasion, angiogenesis and GRB2 level, and inhibited apoptosis of GC cells, while shSYNJ2 exhibited opposite effects. GRB2 overexpression boosted yet shGRB2 suppressed cell migration, invasion and angiogenesis. Notably, SYNJ2 could interact with GRB2. GRB2 overexpression and shGRB2 reversed the effects of shSYNJ2 and overexpressed SYNJ2 on cell migration, invasion and angiogenesis and levels of metastasis-related proteins, respectively. In conclusion, SYNJ2 promotes GC cell metastasis and angiogenesis by up-regulating GRB2.

Gastric cancer (GC) is a common malignant tumor that usually originates from the epithelium of the gastric mucosa. ZNF655 was a suppressor gene of many cancers. However, the mechanism of ZNF655 in GC remains unknown. Quantitative polymerase chain reaction was used to assess the expression of ZNF655, LINC01210, and miR-124-3p. Western blotting was used to monitor ZNF655 protein expression. MTT, clone formation, transwell, and flow cytometry were all used to investigate the functions of GC cells. The interactions between ZNF655, LINC01210, and miR-124-3p were confirmed using the dual-luciferase reporter gene assay and the RIP assay. ZNF655 was highly expressed in GC cells. ZNF655 knockdown reduced GC cell viability, proliferation, migration, invasion, and induced apoptosis. The level of miR-124-3p was significantly reduced in GC cells. Besides, miR-124-3p targeted ZNF655 and inhibited its expression. MiR-124-3p mimics inhibited GC cell progression, but ZNF655 overexpression reversed these effects. Moreover, LINC01210 was found to be highly expressed in GC cells and to be able to sponge miR-124-3p. Furthermore, inhibiting miR-124-3p or increasing ZNF655 could counteract the effects of LINC01210 knockdown on GC cell development. Finally, ZNF655 promoted GC cell progression and was regulated by the LINC01210/miR-124-3p axis.

High-temperature requirement protein A2 (HtrA2), a mitochondrial protein, is related to apoptosis regulation. However, the role of HtrA2 in hepatocellular carcinoma (HCC) remains unclear. In the present study, we explored the prognostic value and expression pattern of HtrA2 in HCC and confirmed its independent value for predicting outcomes via Cox analyses. LinkedOmics and GEPIA2 were used to construct the coexpression and functional networks of HtrA2. Additionally, the data obtained from TCGA was analyzed to investigate the relationship between the infiltration of immune cells and HtrA2 mRNA expression. Finally, the expression pattern of HtrA2 in HCC was confirmed by wet-lab experiments. The results showed high HtrA2 expression (P < 0.001) presented in tumor tissues in TCGA-HCC. Moreover, high HtrA2 expression was confirmed to be associated with poor HCC patient survival (P < 0.05). HtrA2 has also been recognized as an essential risk factor for overall survival (P=0.01, HR = 1.654, 95% CI 1.128-2.425), disease-specific survival (P=0.004, HR = 2.204, 95% CI 1.294-3.753), and progression-free interval (P=0.007, HR = 1.637, 95% CI 1.145-2.341) of HCC. HCC patients with low HtrA2 methylation had worse overall survival than patients with high methylation (P=0.0019). Functional network analysis suggests that HtrA2 regulates mitochondrial homeostasis through pathways involving multiple microRNAs and transcription factors in HCC. In addition, HtrA2 expression correlated with infiltrating levels of multiple immune cell populations. At last, increased expression of HtrA2 in HCC was confirmed using wet-lab experiments. Our study provides evidence that the upregulation of HtrA2 in HCC is an independent predictor of prognosis. Our results provide the foundation for further study on the roles of HtrA2 in HCC tumorigenesis.