It is known that the long noncoding RNAs (lncRNA) MALAT1 is associated with tumorigenesis and progression in various cancers; however, its functions and mechanisms in prostate cancer (PCa) initiation and progression are still unknown. In the present study, our findings revealed that MALAT1 plays a critical part in regulating PCa proliferation and glucose metabolism. Knockdown of MALAT1 affects the protein and mRNA levels of MYBL2. In addition, MALAT1 enhances the phosphorylation level of mTOR pathway by upregulating MYBL2. Knockdown of MALAT1 or MYBL2 in PCa cell lines significantly inhibits their proliferation capacity. Silencing MALAT1/MYBL2/mTOR axis in PCa cell lines affects their glycolysis and lactate levels, and we verified these findings in mice. Furthermore, we explored the underlying tumorigenesis functions of MYBL2 in PCa and found that high expression of MYBL2 was positively associated with TNM stage, Gleason score, PSA level, and poor survival rate in PCa patients. Taken together, our research suggests that MALAT1 controls cancer glucose metabolism and progression by upregulating MYBL2-mTOR axis.

Long noncoding RNA (lncRNA) nuclear enriched abundant transcript 1 (NEAT1) is nuclear-located and transcribed from chromatin 11. To date, little is known about the cellular functions and regulatory mechanisms of NEAT1 in prostate cancer (PCa). In this stud y, whole-genome RNA sequencing data were downloaded from TCGA and GEO databases. Biological information was used to analyze the different expressions of NEAT1. In situ hybridization (ISH) was performed to detect the expression of NEAT1 in PCa and paracarcinomatous clinical samples. Then, NEAT1 was knocked down in PC3 cells through lentiviral infection with a plasmid construct. Bioinformatics and integrative analytical approaches were utilized to identify the relationships of NEAT1 with specific cancer-related gene sets.Cell proliferation assay and colony formation assay were performed to evaluate the cell proliferative ability. Glycolysis stress test, metabolism assay, and infiltrating T-cell function analysis were implemented to assess the changes in metabolism and immune microenvironment of PCa. We found that the expression of NEAT1 was higher in PCa than in non-neoplastic tissues. The cell proliferative capability of PCa cells was significantly reduced in the NEAT1 knockdown group. PCR array and bioinformatics analysis revealed that the enrichment of acidic substance-related gene sets was associated with NEAT1 expression. NEAT1 depletion inhibited PCa cell aerobic glycolysis accompanied by the reduction of lactate levels in the medium. Further, we found that lactate dehydrogenase A LDHA expression was positively regulated by NEAT1. At last, co-culture systems indicated that NEAT1 or LDHA knockdown promoted the secretion of CD8+ T-lymphocyte factors, including TNF--antitumor effects.