Male-specific long non-coding RNA testis-specific transcript, Y-linked 15 promotes gastric cancer cell growth by regulating Wnt family member 1/ß-catenin signaling by sponging microRNA let-7a-5p.

The present study is aimed to investigate the regulatory effects and related mechanism of long non-coding RNA testis-specific transcript, Y-linked 15 (TTTY15) in gastric carcinoma (GC) cell proliferation, migration, invasion, apoptosis and epithelial-mesenchymal transition (EMT). TTTY15 expression in GC tissue samples and cells was detected by quantitative real-time PCR (qRT-PCR), and the correlation between TTTY15 expression and GC clinicopathological indicators was analyzed. Cell counting kit-8 (CCK-8), BrdU, flow cytometry and Transwell assays were performed for detecting GC cell proliferation, migration, invasion and apoptosis. Western blot was performed for detecting the expressions of EMT-associated proteins (N-cadherin and E-cadherin), Wnt family member 1 (Wnt1) protein and ß-catenin protein. Bioinformatics analysis was conducted to predict, and RNA immunoprecipitation (RIP) assay and dual-luciferase reporter gene assay were performed to verify the targeted relationships of microRNA let-7a-5p (let-7a-5p) with TTTY15 and Wnt1 mRNA 3'UTR. It was found that TTTY15 expression was significantly up-regulated in GC tissues and cells, and was associated with advanced TNM stage and poor tumor differentiation. TTTY15 overexpression promoted GC cell proliferation, migration and invasion, the expressions of N-cadherin, Wnt1 and ß-catenin protein, and inhibited the apoptosis and E-cadherin expression, while knocking down TTTY15 had the opposite effects. TTTY15 directly targeted let-7a-5p and negatively regulated its expression. Wnt1 was the target gene of let-7a-5p, and TTTY15 could indirectly and positively regulate Wnt1 expression. In conclusion, TTTY15 promotes GC progression, by regulating the let-7a-5p/Wnt1 axis to activate the Wnt/ß-catenin pathway.

LncRNA testis-specific transcript, Y-linked 15 (TTTY15) promotes proliferation, migration and invasion of colorectal cancer cells via regulating miR-29a-3p/DVL3 axis.

BACKGROUND: Long non-coding RNA testis-specific transcript, Y-linked 15 (TTTY15) is oncogenic in prostate cancer, however its expression and function in colorectal cancer remain largely unknown. METHODS: Paired colorectal cancer samples/normal tissues were collected, and the expression levels of TTTY15, miR-29a-3p and disheveled segment polarity protein 3 (DVL3) were examined by quantitative real-time polymerase chain reaction (qRT-PCR); TTTY15 shRNA and overexpression plasmids were transfected into HT29 and HCT-116 cell lines using lipofectamine reagent, respectively; the proliferation and colony formation were detected by CCK-8 assay and plate colony formation assay; qRT-PCR and Western blot were used to analyze the changes of miR-29a-3p and DVL3; dual-luciferase reporter gene assay was used to determine the regulatory relationships between miR-29a-3p and TTTY15, miR-29a-3p and DVL3. RESULTS: TTTY15 was significantly up-regulated in cancerous tissues of colorectal cancer samples, positively correlated with the expression of DVL3, while negatively correlated with the expression of miR-29a-3p. After TTTY15 shRNAs were transfected into colorectal cancer cells, the proliferation and metastasis of cancer cells were significantly inhibited, while TTTY15 overexpression had opposite biological effects. TTTY15 shRNA could reduce the expression of DVL3 on both mRNA and protein levels, and the luciferase activity of TTTY15 sequence was also inhibited by miR-29a-3p. DVL3 was also validated as a target gene of miR-29a-3p, and it could be repressed by miR-29a-3p mimics or TTTY15 shRNA. CONCLUSION: TTTY15 is abnormally upregulated in colorectal cancer tissues, and it can modulate the proliferation and metastasis of colorectal cancer cells. It functions as the ceRNA to regulate the expression of DVL3 by sponging miR-29a-3p.

MALAT1 overexpression promotes the growth of colon cancer by repressing ß-catenin degradation.

Colon cancer is one of the most common types of cancer and more than 80% of colon cancer cases are associated with Wnt-ß-catenin signaling activation. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a multi-functional long non-coding RNA that is overexpressed in many types of cancers, including colon cancer. In this study, MALAT1 and ß-catenin were found to be overexpressed in tumor samples from 62 patients with colon cancer. A positive correlation was identified between MALAT1 levels and ß-catenin protein levels in tumors. MALAT1 was found to upregulate ß-catenin protein levels in HCT116 and LOVO cells without changing the mRNA expression levels. ß-catenin degradation was confirmed to be upregulated in MALAT1-knockdown cells and inhibited in cells overexpressing MALAT1 overexpressing. MALAT1 was then identified as a negative regulator of GSK-3ß; it did so via promotion of H3K27 trimethylation of the promoter region. In conclusion, MALAT1 is an oncogene in colon cancer, which inhibits ß-catenin degradation by upregulating H3K27 trimethylation and repressing GSK-3ß expression.