Comprehensive analysis on the expression profile and prognostic values of Synaptotagmins (SYTs) family members and their methylation levels in gastric cancer.

Synaptotagmins (SYTs), constitute a family of 17 membrane-trafficking protein, palying crucial roles in the development and progression of human cancers. However, only very few studies have investigated the expression profile and prognostic values of SYTs family members in gastric cancer (GC). Therefore, we comprehensively evaluated the expression, methylation, prognosis and immune significance of SYTs family members through bioinformatics analysis from the online databases in GC. The expressions of SYT4, SYT9, and SYT14 were up-regulated, and negatively associated with their methylation levels in GC. Both the over-expression of SYT4, SYT9 and SYT14 and their hypomethylation levels contributed to an unsatisfactory overall survival (OS) and progression-free survival (PFS) in GC. Moreover, the low expressions of several methylation cg sites (cg02795029, cg07581146, cg15149095, cg19922137, cg25371503, cg26158959, cg02269161, cg03226737, cg08185661, cg16437728, cg22723056 and cg24678137) were significantly correlated with an unfavorable OS and PFS in GC. Furthermore, the expression of SYT4, SYT9 and SYT14 played a pivotal role in immune cells infiltration in GC. Collectively, our current finding suggested that SYT4, SYT9 and SYT14 might be potent prognostic indictors and promising immunotherapeutic targets for GC patients.

RNAi-mediated SYT14 knockdown inhibits the growth of human glioma cell line U87MG.

SYT14 (Synaptotagmin 14) participates in pathomechanical neurodegeneration and contributes to abnormal neurodevelopment. However, the functional mechanism of SYT14 in human glioma tumorigenesis remains unclear. In the present study, we measured the expression levels of SYT14 mRNA in human glioma cell lines, U373MG, U178, and U87MG and neural stem cells (NSC) cell line by RT-PCR, and used lentivirus-mediated small hairpin RNAs (shRNAs) to knock down SYT14 expression in U87MG cells. Changes in SYT14 expression were determined by real-time PCR. Cell proliferation and colony formation assays were used to analyze the role of SYT14 in U87MG cell proliferation, and cell apoptosis was assessed by flow cytometry. SYT14 mRNA expression was detected in the three glioma cell lines, and was highest in the U87MG cell line. The RNAi-mediated knockdown of SYT14 significantly decreased cell proliferation and colony formation in U87MG cells, and caused a moderate increase in apoptosis. Fewer S phase cells and more G2/M phase cells were observed. These data indicate that SYT14 is highly expressed in glioma cells, and may participate in glioma cell proliferation, apoptosis, and colony formation.