<p>Long Non-Coding RNA Cancer Susceptibility 9 (CASC9) Up-Regulates the Expression of ERBB2 by Inhibiting miR-193a-5p in Colorectal Cancer</p>

Abstract

Background: Emerging studies have reported that long non-coding RNAs (lncRNAs) were crucial regulators in the progression of colorectal cancer (CRC). LncRNA susceptibility 9 (CASC9) was involved in several cancers; however, its role in CRC remains unknown. Methods: RT-PCR was done to probe the expression of CASC9 and miR-193a-5p in CRC samples. CRC cell lines (HCT116 and SW480) were used as cell models. The biological influence of CASC9 on cancer cells was studied using CCK-8 assay, Transwell assay and TUNEL assay in vitro, and subcutaneous xenotransplanted tumor model in vivo. Interaction between CASC9 and miR-193a-5p was investigated by bioinformatics analysis, RT-PCR, and luciferase reporter assay. The expression level of the downstream gene of miR-193a-5p, erb-b2 receptor tyrosine kinase 2 (ERBB2), was tested by Western blot. Results: CASC9 was significantly up-regulated in CRC samples, while miR-193a-5p was markedly down-regulated. Overexpression of CASC9 promoted viability, migration and invasion of CRC cells, while overexpression of miR-193a-5p had the opposite effect. CASC9 could down-regulate miR-193a-5p via sponging it, and there was a negative relevancy between CASC9 and miR-193a-5p in CRC samples. CASC9 also enhanced the expression levels of ERBB2, while this effect could be reversed by co-transfection with miR-193a-5p. Conclusion: CASC9, an oncogenic lncRNA, was abnormally up-regulated in CRC tissues, and it could indirectly modulate the expression of ERBB2 via reducing the expression level of miR-193a-5p.

Long non-coding RNA CASC9 promotes gefitinib resistance in NSCLC by epigenetic repression of DUSP1

“…In vitro and in vivo studies uncovered CASC9's important role in gefitinib resistance. Although CASC9 was upregulated and played an oncogenic role in different types of cancers [25][26][27][28] , the function and mechanisms of CASC9 in NSCLC gefitinib resistance has never been investigated.…”

MAGI2‐AS3 rs7783388 polymorphism contributes to colorectal cancer risk through altering the binding affinity of the transcription factor GR to the MAGI2‐AS3 promoter

“…For instance, Zhang et al 33 identified the downregulation of lncRNA CPS1‐IT1 in CRC cells, and CPS1‐IT1 overexpression suppresses metastasis through inactivating HIF‐1α in CRC. lncRNA CASC9 expression was increased in primary colorectal cancer samples, and CASC9 initiates CRC development by regulating miR‐193a‐5p/ERBB2 axis 34 . lncRNA RHPN1‐AS1 was upregulated, and further RHPN1‐AS1 could indirectly regulate OGT through sponging miR‐7‐5p and then promote CRC cell proliferation and invasion 35 .…”

Prognostic and Predictive Values of the Autophagy Signature in Colon Cancer

“…lncRNAs dominate the upstream portion of the RNA network and function as primary effectors of mRNAs, and several lncRNAs are identi ed as potential prognostic factors in COAD [20,30]. Among these 14 lncRNAs in the model, PCAT6, CASC9, MIR4435-2HG, SNHG16, and LINC00513 have been reported to play a role in the pathogenesis and prognosis of various cancer types (31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43). For example, CASC9 has been reported to be upregulated and conferred an oncogenic function in human hepatocellular carcinoma, oral carcinoma, gastric cancer, colorectal cancer, and esophageal cancer [28,[31][32][33].…”

“…For example, CASC9 has been reported to be upregulated and conferred an oncogenic function in human hepatocellular carcinoma, oral carcinoma, gastric cancer, colorectal cancer, and esophageal cancer [28,[31][32][33]. In colorectal cancer, CASC9 was found to be negatively correlated with the miR-193a-5p expression, and promoted tumorigenesis via the miR-193a-5p/ERBB2 axis [34]. Luo et al [35] reported that the higher expression of the oncogenic CASC9 was associated with poor patient outcomes when interacting with CPSF3 to regulate TGF-β signaling.…”