Although the significance of BRD4 in the epigenetic memory and cancer genesis has been intensively investigated, little is known about its function and potential roles during the generation and progression of gastric cancer. We report here that BRD4 increases the proliferation and represses the apoptosis of gastric cancer cells through activating c-MYC via transcriptional and epigenetic regulation mechanisms.
Long non-coding RNAs (lncRNAs), a variety of transcripts without protein coding ability, have recently been reported to play vital roles in gastric cancer (GC) development and progression. However, the biological role of long non-coding RNA LINC00673 in GC is not fully known. In the study, we found that LINC00673 expression was dramatically higher in gastric cancer tissues compared with adjacent normal tissues, and positively associated with lymph node metastasis, distant metastasis and TNM stage in patients. Higher LINC00673 expression predicted poor disease-free survival (DFS) and overall survival (OS) in GC patients. By univariate and multivariate Cox analysis, the results confirmed that higher LINC00673 expression was an independent risk factor of prognosis in patients. Knockdown of endogenous LINC00673 significantly inhibited cell proliferation, colony formation number, cell migration and invasion in GC. Furthermore, knockdown of endogenous LINC00673 reduced the expression levels of PCNA, CyclinD1 and CDK2 in GC cells. RNA immunoprecipitation (RIP) and chromatin immunoprecipitation (ChIP) proved that LINC00673 suppressed KLF4 expression by interacting with EZH2 and DNMT1 in GC cells. Moreover, we confirmed that LINC00673 promoted cell proliferation and invasion by partly repressing KLF4 expression in GC. Taken together, these results indicated that LINC00673 may be a prognostic biomarker and therapeutic target for GC patients.
Gastric cancer (GC) is a highly prevalent type of metastatic tumor. The mechanisms underlying GC metastasis are poorly understood. Some long noncoding RNAs (lncRNAs) reportedly play key roles in regulating metastasis of GC. However, the biological roles of five natural antisense lncRNAs (AC093818.1, CTD-2541M15.1, BC047644, RP11-597M12.1, and RP11-40A13.1) in GC metastasis remain unclear. In this study, the expression of these lncRNAs was measured by quantitative reverse transcription-polymerase chain reaction. Migration and invasion were evaluated by wound-healing and the Transwell assay, respectively. Stable cells were injected into the tail veins of nude mice. Sections of collected lung and liver tissues were stained using hematoxylin and eosin. Protein expression was analyzed by western blot. RNA immunoprecipitation (RIP) assay was used to verify whether the STAT3 and SP1 transcription factors bound to AC093818.1 in GC cells. Expression levels of the five lncRNAs, especially AC093818.1, were significantly upregulated in metastatic GC tissues relative to those in nonmetastatic GC tissues. AC093818.1 expression was correlated with invasion, lymphatic metastasis, distal metastasis, and tumor-node-metastasis stage. AC093818.1 expression was highly sensitive and specific in the diagnosis of metastatic or nonmetastatic GC. AC093818.1 overexpression promoted GC migration and invasion in vitro and in vivo. AC093818.1 overexpression increased PDK1, p-AKT1, and p-mTOR expression levels. AC093818.1 silencing decreased these expressions. AC093818.1 bound to transcription factors STAT3 and SP1, and SP1 or STAT3 silencing could alleviated the effect of AC093818.1 overexpression. The data demonstrate that lncRNA AC093818.1 accelerates gastric cancer metastasis by epigenetically promoting PDK1 expression. LncRNA AC093818.1 may be a potential therapeutic target for metastatic GC.
In view of the acceptable morbidity and mortality rates we propose that CRS combined with HIPEC presents an effective and safe treatment modality for patients with gastric cancer, especially in cases where optimal cytoreduction is achieved before the HIPEC procedure.
MicroRNAs (miRNAs) have been documented as having an important role in the development of cancer. Broccoli is very popular in large groups of the population and has anticancer properties. Junctional adhesion molecule A (JAMA) is preferentially concentrated at tight junctions and influences cell morphology and migration. Epithelial–mesenchymal transition (EMT) is a developmental program associated with cancer progression and metastasis. In this study we aimed to investigate the role of miRNAs from broccoli in human nasopharyngeal cancer (NPC). We demonstrated that a total of 84 conserved miRNAs and 184 putative novel miRNAs were found in broccoli by sequencing technology. Among these, miR156a was expressed the most. In addition, synthetic miR156a mimic inhibited the EMT of NPC cells in vitro. Furthermore, it was confirmed that JAMA was the target of miR156a mimic as validated by 3’ UTR luciferase reporter assays and western blotting. Knockdown of JAMA was consistent with the effects of miR156a mimic on the EMT of NPC, and the up-regulation of JAMA could partially restore EMT repressed by miR156a mimic. In conclusion, these results indicate that the miR156a mimic inhibits the EMT of NPC cells by targeting the 3’ UTR of JAMA. These miRNA profiles of broccoli provide a fundamental basis for further research. Moreover, the discovery of miR156a may have clinical implications for the treatment of patients with NPC.
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