ABSTRACT
Exosomes are involved in invasion, migration and angiogenesis of tumor cells, and invasion is the main cause of death in glioma patients. Studies have shown that the exosomes secreted by tumor cells can carry miRNA into the receptor cells and regulate the biological functions of the receptor cells, such as proliferation, migration and invasion. miR-574-5p plays a key role in the occurrence and development of a variety of tumors. However, whether the exosomes derived from glioma cells express miR-574-5p and its role in the growth, invasion and migration of glioma cells have not been reported. This study investigated the mechanism of the exosomal miR-574-5p secreted from glioma cells in the process of cell proliferation, migration and invasion. The exosomes were characterized by electron microscopy, nanoparticle size tracking and Western blot. The results displayed that the extracted exosomes were round particles with a diameter of 30 ~ 100 nm. The internalization of exosomes was detected by immunofluorescence assay. The results showed that exosomes were internalized into LN229 cells; Bioinformatics and online data were used to screen the differentially secreted miRNA between LN229 and H4 glioma cells. The results showed that the differentially secreted miRNA was miR-574-5p, and large tumor suppressor 2 (LATS2) was predicted to be the target gene of miR-574-5p; Duel luciferase reporter assay confirmed that miR-574-5p was complementary to the 3'UTR region of LATS2; The transfection assay, qRT-PCR and Western blot was conducted to measure the relationship between miR-574-5p and LATS2. The results demonstrated that there was no significant difference in LATS2 mRNA levels between the control group and the group with miR-574-5P overexpression (P > 0.05), suggesting the regulatory effect of miR-574-5P on LATS2 was achieved by inhibiting its translation (P < 0.05). CCK-8, Transwell migration and invasion assays were conducted to explore the effect of miR-574-5p on proliferation, migration and invasion of LN229 cells. The results showed that overexpression of miR-574-5p could significantly promote the ability of proliferation, migration and invasion of LN229 cells (P < 0.05). In addition, Western blot was performed to measure the expression of kinase proteins involved in the LATS2/YAP signaling pathway, and the influence of the exosomes on this signaling pathway. The results revealed that the exosomes down-regulated the protein expression level of LATS2 and reduced p-YAP phosphorylation. In conclusion, the exosomal miR-574-5p can promote the proliferation, migration and invasion of glioma cells by down-regulating LATS2 and activating LATS2/YAP signaling pathway, which may provide a potential biomarker for the diagnosis and target for the treatment of glioma.
ABSTRACT
PURPOSE: The aims of this study were to evaluate the expression of the large tumor suppressor (LATS) genes LATS1 and LATS2 by immunohistochemical staining of gastric cancer, and to evaluate the clinicopathological significance of LATS expression and its correlation with overall survival (OS). MATERIALS AND METHODS: LATS1 and LATS2 expression in a tissue microarray was detected by immunohistochemistry, using 264 gastric cancer specimens surgically resected between July 2006 and December 2009. RESULTS: Low expression of LATS1 was significantly associated with more advanced American Joint Committee on Cancer (AJCC) stage (P=0.001) and T stage (P=0.032), lymph node (LN) metastasis (P=0.040), perineural invasion (P=0.042), poor histologic grade (P=0.007), and diffuse-type histology by the Lauren classification (P=0.033). Low expression of LATS2 was significantly correlated with older age (≥65, P=0.027), more advanced AJCC stage (P=0.001) and T stage (P=0.001), LN metastasis (P=0.004), perineural invasion (P=0.004), poor histologic grade (P<0.001), and diffuse-type histology by the Lauren classification (P<0.001). Kaplan-Meier survival analysis revealed significantly poor OS rates in the groups with low LATS1 (P=0.037) and LATS2 (P=0.037) expression. CONCLUSIONS: Expression of LATS1 or LATS2 is a significant marker for a good prognosis in patients with gastric cancer.
Subject(s)
Humans , Classification , Genes, Tumor Suppressor , Immunohistochemistry , Joints , Long-Acting Thyroid Stimulator , Lymph Nodes , Neoplasm Metastasis , Prognosis , Stomach NeoplasmsABSTRACT
RT-PCR and Western blot were used to detect the LATS2 mRNA and protein level in 57 cases of oral squamous cell carcinoma (OSCC)specimens and 12 normal oral mucosa tissues.LATS2 mRNA and protein were expressed in all the normal oral mucosa samples (100%),but only 47.4% (27 /57)and 42.1% (24 /57)in OSCC samples respectively with positive correlation of both(P <0.01),and were respectively correlated with the tumor differentiation degree and lymph node metastasis(P <0.05).