Long non-coding RNA CCAT1 promotes metastasis and poor prognosis in epithelial ovarian cancer

LncRNA CASC15 promotes colon cancer cell proliferation and metastasis by regulating the miR‑4310/LGR5/Wnt/β‑catenin signaling pathway

Previous studies have indicated that overexpression of long noncoding RNA cancer susceptibility 15 (CASC15) may promote tumor development and progression in gastric cancer and hepatocellular carcinoma. However, the function of CASC15 in colon cancer remains unknown. In the present study, the expression of CASC15 was upregulated in colon cancer tissues and its expression was correlated with clinical Tumor‑Node‑Metastasis stage and tumor metastasis. In addition, knockdown of CASC15 significantly inhibited the proliferation, migration and invasion of colon cancer cells in vitro and in vivo. Following mechanistic experiments, CASC15 was observed to act as a sponge to suppress microRNA (miR)‑4310 that targeted LGR5. Through the inhibition of miR‑4310, CASC15 promoted leucine‑rich repeat‑containing G‑protein coupled receptor 5 (LGR5) expression and consequently activated the Wnt/β‑catenin signaling pathway. The results revealed that the inhibition of the Wnt/β‑catenin signaling pathway in CASC15‑overexpressing colon cancer cells suppressed cellular proliferation, migration and invasion. Collectively, these results demonstrated that CASC15 promoted colon cancer growth and metastasis through the activation of the Wnt/β‑catenin signaling pathway in a miR‑4310/LGR5 dependent manner. Thus, the present study suggested that CASC15 may be a therapeutic target for colon cancer treatment.

Functional Role of Non-Coding RNAs during Epithelial-To-Mesenchymal Transition

Epithelial-to-mesenchymal transition (EMT) is a key biological process involved in a multitude of developmental and pathological events. It is characterized by the progressive loss of cell-to-cell contacts and actin cytoskeletal rearrangements, leading to filopodia formation and the progressive up-regulation of a mesenchymal gene expression pattern enabling cell migration. Epithelial-to-mesenchymal transition is already observed in early embryonic stages such as gastrulation, when the epiblast undergoes an EMT process and therefore leads to the formation of the third embryonic layer, the mesoderm. Epithelial-to-mesenchymal transition is pivotal in multiple embryonic processes, such as for example during cardiovascular system development, as valve primordia are formed and the cardiac jelly is progressively invaded by endocardium-derived mesenchyme or as the external cardiac cell layer is established, i.e., the epicardium and cells detached migrate into the embryonic myocardial to form the cardiac fibrous skeleton and the coronary vasculature. Strikingly, the most important biological event in which EMT is pivotal is cancer development and metastasis. Over the last years, understanding of the transcriptional regulatory networks involved in EMT has greatly advanced. Several transcriptional factors such as Snail, Slug, Twist, Zeb1 and Zeb2 have been reported to play fundamental roles in EMT, leading in most cases to transcriptional repression of cell⁻cell interacting proteins such as ZO-1 and cadherins and activation of cytoskeletal markers such as vimentin. In recent years, a fundamental role for non-coding RNAs, particularly microRNAs and more recently long non-coding RNAs, has been identified in normal tissue development and homeostasis as well as in several oncogenic processes. In this study, we will provide a state-of-the-art review of the functional roles of non-coding RNAs, particularly microRNAs, in epithelial-to-mesenchymal transition in both developmental and pathological EMT.

Long non-coding RNA RP11-552M11.4 promotes cells proliferation, migration and invasion by targeting BRCA2 in ovarian cancer

The present study aimed to investigate the effect of long non‐coding RNA (lncRNA) RP11‐552M11.4 on cell proliferation, apoptosis, migration and invasion as well as its targeting genes in epithelial ovarian cancer (EOC) cells. LncRNA RP11‐552M11.4 expression was detected in 67 tumor tissues and paired adjacent tissues obtained from EOC patients. lncRNA RP11‐552M11.4 mimic/inhibitor plasmids were transferred into ovarian cancer cells (SKOV3, A‐2780) and normal ovarian epithelial cells (IOSE80 cells). In addition, rescue experiment was carried out by transferring BRCA2 inhibitor&lncRNA RP11‐552M11.4 inhibitor plasmids into SKOV3 and A‐2780 cells. qPCR, western blot, CKK‐8, Annexin V/propidium iodide (AV/PI), wound‐healing and Matrigel invasion assays were carried out to detect RNA expression, protein expression, cell proliferation, apoptosis, migration, and invasion, respectively. LncRNA RP11‐552M11.4 expression was elevated in tumor tissues compared with paired adjacent tissues and correlated with higher pathological grade, International Federation of Gynecology and Obstetrics stage and worse overall survival in EOC patients. LncRNA RP11‐552M11.4 promoted SKOV3 cell proliferation, migration and invasion whereas it inhibited apoptosis. Rescue experiment and luciferase reporter assay showed that lncRNA RP11‐552M11.4 regulated SKOV3 cells functions through binding BRCA2. Further experiments in A‐2780 cells also validated that lncRNA RP11‐552M11.4 induced A‐2780 cell proliferation while repressing apoptosis by targeting BRCA2. In addition, upregulation of lncRNA RP11‐552M11.4 increased IOSE80 cell proliferation, migration and invasion while decreasing apoptosis. In conclusion, lncRNA RP11‐552M11.4 correlates with worse prognosis, and promotes cell proliferation, migration, invasion, and inhibits cell apoptosis by down‐regulating BRCA2 in EOC.

Long noncoding RNA CCAT1 polymorphisms are associated with the risk of colorectal cancer

Colorectal cancer associated transcript 1 (CCAT1) is a novel long noncoding RNA, whose overexpression is evident in both early phase of tumorigenesis and later disease stages in colorectal cancer (CRC). No study has explored the relationship between CCAT1 polymorphisms and CRC risk. In the present study, a case-control study was conducted to investigate the association between CCAT1 polymorphisms and CRC risk in Chinese population. We identified that CCAT1 rs67085638 polymorphism was associated with an increased risk of CRC (OR = 1.72, 95%CI = 1.14-2.58, P = 0.009 in heterozygote codominant model; OR = 1.67, 95%CI = 1.13-2.47, P = 0.010 in dominant model). Moreover, CCAT1 rs7013433 polymorphism was associated with late clinical stage (OR = 1.82, 95%CI = 1.16-2.86, P = 0.009 in heterozygote codominant model; OR = 1.72, 95%CI = 1.13-2.63, P = 0.012 in dominant model). Our finding proposed a link between CCAT1 polymorphisms with CRC risk as well as different clinical stages.