RESUMO
Fiber sheath interaction protein 1 (FSIP1) plays a crucial role in cancer development and occurrence, but its influence on gastric cancer is still unclear. In this study, differential mRNA analysis was performed by TCGA database for the Limma analysis algorithm, and the gene ontology, the Kyoto Encyclopedia of Genes and Genomes, and the gene set enrichment analysis (GSEA) were used for bioinformatics functional enrichment analysis. A gastric cancer cell model with FSIP1 mRNA knockdown was constructed by RNA interference. Cell counting kit-8 and transwell migration/invasion assay were performed to verify the cell function, and western blotting was employed to confirm the expression of target genes. The GSEA analysis revealed that FSIP1 was associated with epithelial-mesenchymal transition (EMT). The high expression group also had a significant positive correlation with the markers of fibroblast in tumor microenvironment (TME). Western blotting showed that FSIP1 was generally upregulated in gastric cancer cell lines. FSIP1 mRNA knockdown cell lines inhibited gastric cells proliferation, migration, and metastasis in vitro, and the protein levels of EMT-related markers N-cadherin and vimentin were reduced. Our work proved that FSIP1 promoted EMT by regulating fibroblasts in the TME, thereby promoting the carcinogenic activity of cancer cells in proliferation, invasion, and migration. FSIP1 may take a role of the occurrence and could be a potential therapeutic target and offer a new insight into the underlying mechanism of gastric cancer.
RESUMO
VEGF165 and its isoform VEGF165b have the same length but opposite functions in cancer. Some studies have indicated the important role of VEGF165 in osteosarcoma (OS); however, VEGF165b has not been taken into consideration. This study aims to clarify the roles of the two isoforms in OS and the mechanism controlling their formation from an alternative splicing perspective. By in vivo and in vitro experiments, we assessed the expression and function of VEGF165 and VEGF165b, screened the underlying splicing factors, and verified the regulatory function of splicing factor YBX1 on the two isoforms and its role in OS. The results showed that in OS, VEGF165 was upregulated but VEGF165b was downregulated. VEGF165 promoted the proliferation, migration and invasion of OS cells and induced angiogenesis in OS tumours; however, VEGF165b showed the opposite function. Of the four screened splicing factors, YBX1 was upregulated in OS tissues. It was positively correlated with VEGF165 but negatively correlated with VEGF165b. Further study indicated that YBX1 could upregulate VEGF165 but downregulate VEGF165b. Moreover, YBX1 promoted the proliferation, migration and invasion of OS cells and induced angiogenesis in OS tumours. OS patients with higher YBX1 had a poor prognosis within five years, but this difference disappeared in a longer follow-up. In conclusion, VEGF165b was antineoplastic and downregulated in OS, in contrast to VEGF165. YBX1 was found to be an important splicing factor that increased VEGF165 but decreased VEGF165b. Targeting YBX1 could endogenously alter the levels of VEGF165 and VEGF165b simultaneously.
RESUMO
Gastric cancer (GC) is one of the most common upper gastrointestinal malignant tumors, and the incidence of the GC shows an increasing trend in the past years. Finding more sensitive markers will help to reveal the mechanism of GC progression and clinic diagnoses. This study first analyzed the mRNA expression level of FSIP1 in TCGA GC samples and the significance in predicting the prognosis. KEGG and GO analyses were used to explore the molecular mechanism of FSIP1 in GC progression. This study further retrospectively analyzed 166 clinical samples of GC from Harbin Medical University Cancer Hospital and evaluated the expression level of FSIP1 by immunohistochemistry. Kaplan-Meier and Cox multivariate analysis was used to investigate the prognostic value of FSIP1 expression in GC patients. We also identified correlations between FSIP1 and clinicopathological characteristics. This study found that the mRNA level of FSIP1 was significantly upregulated in GC compared with nontumor specimens and correlated with poor prognosis. Immunohistochemistry confirmed the results of bioinformatics analysis of the TCGA GC database. FSIP1 was associated with pTNM pathological stage, tumor location, and neural invasion. In addition, multivariate Cox regression analysis showed that FSIP1, T classification, and N classification were independent posterior factors of patients and could be combined with pathological features to construct a nomogram prognostic model. Overall, our results suggest that FSIP1 is expected to be an independent prognostic indicator of GC.
