shRNA targeting long non-coding RNA CCAT2 controlled by tetracycline-inducible system inhibits progression of bladder cancer cells

Non-coding RNA transcripts, incredible modulators of cisplatin chemo-resistance in bladder cancer through operating a broad spectrum of cellular processes and signaling mechanism

Bladder cancer (BC) is a highly frequent neoplasm in correlation with significant rate of morbidity, mortality, and cost. The onset of BC is predominantly triggered by environmental and/or occupational exposures to carcinogens, such as tobacco. There are two distinct pathways by which BC can be developed, including non-muscle-invasive papillary tumors (NMIBC) and non-papillary (or solid) muscle-invasive tumors (MIBC). The Cancer Genome Atlas project has further recognized key genetic drivers of MIBC along with its subtypes with particular properties and therapeutic responses; nonetheless, NMIBC is the predominant BC presentation among the suffering individuals. Radical cystoprostatectomy, radiotherapy, and chemotherapy have been verified to be the common therapeutic interventions in metastatic tumors, among which chemotherapeutics are more conventionally utilized. Although multiple chemo drugs have been broadly administered for BC treatment, cisplatin is reportedly the most effective chemo drug against the corresponding malignancy. Notwithstanding, tumor recurrence is usually occurred following the consumption of cisplatin regimens, particularly due to the progression of chemo-resistant trait. In this framework, non-coding RNAs (ncRNAs), as abundant RNA transcripts arise from the human genome, are introduced to serve as crucial contributors to tumor expansion and cisplatin chemo-resistance in bladder neoplasm. In the current review, we first investigated the best-known ncRNAs, i.e. microRNAs (miRNAs), long ncRNAs (lncRNAs), and circular RNAs (circRNAs), correlated with cisplatin chemo-resistance in BC cells and tissues. We noticed that these ncRNAs could mediate the BC-related cisplatin-resistant phenotype through diverse cellular processes and signaling mechanisms, reviewed here. Eventually, diagnostic and prognostic potential of ncRNAs, as well as their therapeutic capabilities were highlighted in regard to BC management.

Molecular landscape of LncRNAs in bladder cancer: From drug resistance to novel LncRNA-based therapeutic strategies

Bladder cancer (BC) is a common and serious type of cancer that ranks among the top ten most prevalent malignancies worldwide. Due to the high occurrence rate of BC, the aggressive nature of cancer cells, and their resistance to medication, managing this disease has become a growing challenge in clinical care. Long noncoding RNAs (lncRNAs) are a group of RNA transcripts that do not code for proteins and are more than 200 nucleotides in length. They play a significant role in controlling cellular pathways and molecular interactions during the onset, development and progression of different types of cancers. Recent advancements in high-throughput gene sequencing technology have led to the identification of various differentially expressed lncRNAs in BC, which indicate abnormal expression. In this review, we summarize that these lncRNAs have been found to impact several functions related to the development of BC, including proliferation, cell growth, migration, metastasis, apoptosis, epithelial-mesenchymal transition, and chemo- and radio-resistance. Additionally, lncRNAs may improve prognosis prediction for BC patients, indicating a future use for them as prognostic and diagnostic biomarkers for BC patients. This review highlights that genetic tools and anti-tumor agents, such as CRISPR/Cas systems, siRNA, shRNA, antisense oligonucleotides, and vectors, have been created for use in preclinical cancer models. This has led to a growing interest in using lncRNAs based on positive research findings.

Epigenetic and Immunological Features of Bladder Cancer

Bladder cancer (BLCA) is one of the most common types of malignant tumors of the urogenital system in adults. Globally, the incidence of BLCA is more than 500,000 new cases worldwide annually, and every year, the number of registered cases of BLCA increases noticeably. Currently, the diagnosis of BLCA is based on cystoscopy and cytological examination of urine and additional laboratory and instrumental studies. However, cystoscopy is an invasive study, and voided urine cytology has a low level of sensitivity, so there is a clear need to develop more reliable markers and test systems for detecting the disease with high sensitivity and specificity. Human body fluids (urine, serum, and plasma) are known to contain significant amounts of tumorigenic nucleic acids, circulating immune cells and proinflammatory mediators that can serve as noninvasive biomarkers, particularly useful for early cancer detection, follow-up of patients, and personalization of their treatment. The review describes the most significant advances in epigenetics of BLCA.

Long non-coding RNA colon cancer-associated transcript 2: role and function in human cancers

ABSTRACT

Long non-coding RNAs (lncRNAs) are a family of non-protein-coding RNAs that span a length of over 200 nucleotides. Research reports have illustrated that lncRNAs are involved in various cellular processes and that their abnormal expression leads to the occurrence and development of various tumors. Colon cancer-associated transcript 2 (CCAT2) was first reported as an oncogene in colon cancer. LncRNA CCAT2 is abnormally expressed in hepatocellular carcinoma, cholangiocarcinoma, lung cancer, breast cancer, ovarian cancer, glioma, and other tumors. In tumor tissues, abnormally overexpressed CCAT2 can affect cell proliferation, migration, epithelial-mesenchymal transition, apoptosis, and other biological behaviors through endogenous RNAs mechanisms, various signaling pathways, transcriptional regulation, and other complex mechanisms. Additionally, the overexpression of CCAT2 is also closely related to the tumor size, tumor node metastasis (TNM) stage, survival time, and other prognostic factors, suggesting that it is a potential prognostic indicator. This article reviews the biological functions of CCAT2 and its mechanisms of action in tumors from previous studies. In this review, we attempt to provide a molecular basis for future clinical applications of lncRNA CCAT2.

The roles of long non‑coding RNAs in renal cell carcinoma (Review)

Long non-coding RNAs (lncRNAs) are involved in the gene expression regulation and usually play important roles in various human cancers, including the renal cell carcinoma (RCC). Dysregulation of certain lncRNAs are associated with the prognosis of patients with RCC. In the present review, several recently studied lncRNAs were discussed and their critical roles in proliferation, migration, invasion, apoptosis and drug resistance of renal cancer cells were revealed. The research on lncRNAs further increases our understanding on the development and progression of RCC. It is suggested that lncRNAs can be used as biomarkers or therapeutic targets for diagnosis or treatment of renal cancer.

Long noncoding RNA CCAT2 reduces chemosensitivity to 5-fluorouracil in breast cancer cells by activating the mTOR axis

Breast cancer (BC) is the most prevalent cancer in women and the second leading cause for cancer‐related death in women. LncRNA CCAT2 is involved in BC cell drug sensitivity. Drug resistance of BC cells after chemotherapy is the main obstacle to therapeutic effects. This study explored whether BC cell drug sensitivity to 5‐Fu was related to lncRNA CCAT2‐regulated mTOR pathway. Normal breast tissues and BC tissues before/after neoadjuvant chemotherapy were collected, and CCAT2 expression was detected by RT‐qPCR. Correlation between CCATA2 expression and neoadjuvant chemotherapy efficacy was analysed using the Kendall's tau‐b correlation analysis. Normal breast epithelial cells and BC cell lines were cultured. BC cell lines were treated with 5‐Fu, and CCAT2 mRNA level in cells was detected. The 5‐Fu‐resistant MCF‐7/5‐Fu and MDA‐MB‐231/5‐Fu cells were treated with CCAT2 overexpression/knockdown or CCI‐779 (the mTOR pathway inhibitor). The mTOR pathway levels were detected. Expression of apoptosis‐related factors was identified. A subcutaneous xenograft model was carried out. High CCAT2 expression was detected in BC tissues and BC drug‐resistant cells after neoadjuvant chemotherapy, and a negative link was revealed between CCAT2 expression and efficacy of neoadjuvant chemotherapy. p‐mTOR/mTOR in 5‐Fu‐resistant BC cells with inhibited CCAT2 was decreased, while CCAT2 overexpression activated the mTOR pathway. IC50 value, proliferation, cells in S phase increased and apoptosis reduced after CCAT2 overexpression. After si‐CCAT2 or CCI‐779 treatment, the growth rate of transplanted tumours was inhibited, while promoted after CCAT2 overexpression. CCAT2 may reduce BC cell chemosensitivity to 5‐Fu by activating the mTOR pathway.

Serum CCAT2 as a biomarker for adjuvant diagnosis and prognostic prediction of cervical cancer

Growing evidence indicates that lncRNA colon cancer-associated transcript 2 (CCAT2) is associated with cancers. However, the clinical value of CCAT2 in cervical cancer (CC) remains unclear. In this study, serum CCAT2 level was detected by real-time quantitative PCR (RT-qPCR). Carbohydrate antigen 125 (CA125) and squamous-cell carcinoma antigen (SCC) were detected by electrochemiluminescence. A receiver operating characteristic (ROC) curve was utilized to estimate the diagnostic efficiency of CCAT2. Kaplan-Meier survival analysis and univariable and multivariable analyses were performed to assess the prognostic value of CCAT2. The relative expression level of CCAT2 in primary CC patients was significantly higher than that in cervical intraepithelial neoplasias (CIN) patients and healthy controls (both P < 0.001). CCAT2 relative expression was positively correlated with tumor Federation of Gynecology and Obstetrics (FIGO) stage, SCC-Ag and lymph node metastasis (LNM) (all P < 0.05). CCAT2 expression in recurrent/metastatic CC was significantly higher compared with primary CC (P < 0.0001) or operated CC (P < 0.0001) and during follow-up, CCAT2 expression was increased before surgery and decreased significantly after surgery (P < 0.0001). Furthermore, the overall survival rate of CC patients with high CCAT2 expression group markedly decreased as compared with that of low CCAT2 expression group (P = 0.026). Univariate analyses indicated that CCAT2 was a poor prognostic factor associated with overall survival (OS). Our study indicates that CCAT2 may be valuable in complementary diagnosis and monitoring of progression and prognosis of CC patients. Combined detection of CCAT2, CA125 and SCC can greatly improve the diagnostic efficiency of primary CC.

The Roles of the Colon Cancer Associated Transcript 2 (CCAT2) Long Non-Coding RNA in Cancer: A Comprehensive Characterization of the Tumorigenic and Molecular Functions

Colon cancer-associated transcript 2 (CCAT2) is an intensively studied lncRNA with important regulatory roles in cancer. As such, cumulative studies indicate that CCAT2 displays a high functional versatility due to its direct interaction with multiple RNA binding proteins, transcription factors, and other species of non-coding RNA, especially microRNA. The definitory mechanisms of CCAT2 are its role as a regulator of the TCF7L2 transcription factor, enhancer of MYC expression, and activator of the WNT/β-catenin pathway, as well as a role in promoting and maintaining chromosome instability through the BOP1–AURKB pathway. Additionally, we highlight how the encompassing rs6983267 SNP has been shown to confer CCAT2 with allele-specific functional and structural particularities, such as the allelic-specific reprogramming of glutamine metabolism. Additionally, we emphasize CCAT2’s role as a competitive endogenous RNA (ceRNA) for multiple tumor suppressor miRNAs, such as miR-4496, miR-493, miR-424, miR-216b, miR-23b, miR-34a, miR-145, miR-200b, and miR-143 and the pro-tumorigenic role of the altered regulatory axis. Additionally, due to its upregulation in tumor tissues, wide distribution across cancer types, and presence in serum samples, we outline CCAT2’s potential as a biomarker and disease indicator and its implications for the development of resistance against current cancer therapy regiments and metastasis.

Long non-coding RNAs as new players in bladder cancer: Lessons from pre-clinical and clinical studies

The clinical management of bladder cancer (BC) has become an increasing challenge due to high incidence rate of BC, malignant behavior of cancer cells and drug resistance. The non-coding RNAs are considered as key factors involved in BC progression. The long non-coding RNAs (lncRNAs) are RNA molecules and do not encode proteins. They have more than 200 nucleotides in length and affect gene expression at epigenetic, transcriptional and post-transcriptional phases. The lncRNAs demonstrate abnormal expression in BC cells and tissues. The present aims to identifying lncRNAs with tumor-suppressor and tumor-promoting roles, and evaluating their roles as regulatory of growth and migration. Apoptosis, glycolysis and EMT are tightly regulated by lncRNAs in BC. Response of BC cells to cisplatin, doxorubicin and gemcitabine chemotherapy is modulated by lncRNAs. LncRNAs regulate immune cell infiltration in tumor microenvironment and affect response of BC cells to immunotherapy. Besides, lncRNAs are able to regulate microRNAs, STAT3, Wnt, PTEN and PI3K/Akt pathways in affecting both proliferation and migration of BC cells. Noteworthy, anti-tumor compounds and genetic tools such as siRNA, shRNA and CRISPR/Cas systems can regulate lncRNA expression in BC. Finally, lncRNAs and exosomal lncRNAs can be considered as potential diagnostic and prognostic tools in BC.

The Anti-Tumor Activity of Afatinib in Pancreatic Ductal Adenocarcinoma Cells

BACKGROUND

Pancreatic Ductal Adenocarcinoma (PDAC) is the most common form of pancreatic cancer and leading causes of pancreatic cancer death because of most PDAC patients with advanced unresectable disease at that time, which is remarkably resistant to all forms of chemotherapy and radiotherapy.

OBJECTIVE

PDAC increases the social and patient's family burden. However, the PDAC pathogenesis is not identified. We are trying to uncover the underlying mechanism in the future.

METHODS

In our research, the drug-resistant cell line was successfully induced in the vitro by progressive concentrations of Afatinib, which we named it as BxPC3-AR.

RESULTS

It has been observed that the effect of autophagy was on the resistance of BxPC3-AR to Afatinib.

CONCLUSION

It has been confirmed that autophagy plays a certain role in BxPC3-AR resistance to Afatinib. Our findings provide a new perspective on the role of autophagy in pancreatic ductal adenocarcinoma.

CRISPR-CasRx Targeting LncRNA LINC00341 Inhibits Tumor Cell Growth in vitro and in vivo

CRISPR-CasRx technology provides a new and powerful method for studying cellular RNA in human cancer. Herein, the pattern of expression of long noncoding RNA 00341 (LINC00341) as well as its biological function in bladder cancer were studied using CRISPR-CasRx. qRT-PCR was employed to quantify the levels of expression of LINC00341 in tumor tissues along with the matched non-tumor tissues. sgRNA targeting LINC00341 or the sgRNA negative control were transiently transfected into the T24 as well as 5,637 human bladder cancer cell lines. CCK-8, ELISA as well as wound healing methods were employed to explore cell proliferation, apoptosis and migration, respectively. The tumorigenicity experiment in nude mice also performed to detect cell proliferation. The expression of p21, Bax as well as E-cadherin were assayed using western blot. The results demonstrated that LINC00341 was overexpressed in bladder cancer in contrast with the healthy tissues. The LINC00341 expression level in high-grade tumors was higher in contrast with that in low-grade tumors. The expression of linc00341 was higher relative to that of non-invasive tumors. In T24 as well as 5637-cell lines harboring LINC00341-sgRNA, inhibition of cell proliferation (in vitro and in vivo), elevated apoptosis rate and diminished migration ability. Moreover, silencing LINC00341 upregulated the expressions of p21, Bax as well as E-cadherin. Knockout of these genes could eliminate the phenotypic changes caused by sgRNA targeting LINC00341. Our data demonstrate that LINC00341 has a carcinogenic role in human bladder cancer.

Expression of lncRNA CCAT2 in children with neuroblastoma and its effect on cancer cell growth

The aim of this study was to determine the expression of long-chain non-coding RNA (lncRNA) colon cancer-associated transcript 2 (CCAT2) in children with neuroblastoma and its effect on cancer cell growth. A polymerase chain reaction assay was carried out to quantify lncRNA CCAT2 miRNA in neuroblastoma cells, corresponding paracancerous cells, SH-SY5Y and SK-N-SH cells, and human umbilical vein endothelial cells (HUVEC), and two groups of children with different lncRNA CCAT2 expression were compared in clinical pathological parameters and prognosis. CCAT2-NC and si-CCAT2 were transfected into SH-SY5Y cells, separately. Then a 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay was carried out to analyze the cell proliferation, migration, and invasion ability, a flow cytometry to detect cell apoptosis, and a Western blotting (WB) assay to quantify p53 and Bcl-2 proteins. lncRNA CCAT2 expression in cancer tissues of children with neuroblastoma was notably higher than that in corresponding paracancerous tissues (P < 0.05), and children with different tissue differentiation, tumor staging, and lymph node metastasis (LNM) showed notably different lncRNA CCAT2 expression (P < 0.05). In addition, children with neuroblastoma in the high lncRNA CCAT2 expression group showed lower 3-year survival rate than those in the low expression group (P < 0.05). Multivariate analysis revealed that tissue differentiation, tumor-node-metastasis staging, LNM, and lncRNA CCAT2 expression were all independent risk factors affecting the prognosis of children with neuroblastoma (all P < 0.05). Compared with HUVEC cells, SH-SY5Y and SK-N-SH cells showed notably up-regulated lncRNA CCAT2, and the expression of it in SH-SY5Y was higher than that in SK-N-SH cells (P < 0.05). Compared with the CCAT2-NC group, the si-CCAT2 group presented notably down-regulated CCAT2 (P < 0.05). Moreover, according to the MTT assay, the si-CCAT2 group showed notably weakened cell viability and proliferation than the CCAT2-NC group (both P < 0.05), and SH-SY5Y cells in the former group were less active than those in the latter group in terms of migration and invasion. The cell apoptosis rate of SH-SY5Y cells in the si-CCAT2 was higher than that in the CCAT2-NC. The results suggested that knock down of lncRNA CCAT2 could improve the apoptosis activity of neuroblastoma cells in children. According to the WB assay, the si-CCAT2 group showed notably higher p53 expression and notably lower Bcl-2 protein expression than the CCAT2-NC group (both P < 0.05). LncRNA CCAT2 can inhibit the proliferation of neuroblastoma cells and promote their apoptosis, which provides a basis for the treatment of neuroblastoma.

CRISPR-Cas13-Mediated Knockdown of lncRNA-GACAT3 Inhibited Cell Proliferation and Motility, and Induced Apoptosis by Increasing p21, Bax, and E-Cadherin Expression in Bladder Cancer

The current study is to investigate the expression pattern and biological function of long non-coding RNA Focally gastric cancer-associated transcript3 (GACAT3) in bladder cancer. Real-time quantitative qPCR was used to detect the expression level of GACAT-3 in tumor tissues and paired normal tissues. Human bladder cancer T24 and 5637 cell lines were transiently transfected with specific CRISPR-Cas13 or negative control CRISPR-Cas13. Cell migration, proliferation, and apoptosis were measured by using wound healing assay CCK-8 assay and Caspase-3 ELISA assay, respectively. The expression changes of p21, Bax, and E-cadherin after knockdown of GACAT3 were detected by using Western blot. The results demonstrated that GACAT3 was up-regulated in bladder cancer tissues than that in the paired normal tissues. Inhibition of cell proliferation, increased apoptosis, and decreased motility were observed in T24 and 5637 cell lines transfected by CRISPR-Cas13 targeting GACAT3. Downregulation of GACAT3 increased p21, Bax, and E-cadherin expression and silencing these genes could eliminate the phenotypic changes induced by knockdown of GACAT3. A ceRNA mechanism for GACAT3 was also revealed. By using CRISPR-Cas13 biotechnology, we suggested that GACAT3 may be a novel target for diagnosis and treatment of bladder cancer.

CircAMOTL1 Promotes Tumorigenesis Through miR-526b/SIK2 Axis in Cervical Cancer

Background

Cervical cancer is one of the most common malignancies in women, leading to major health problems for its high morbidity and mortality. Numerous studies have demonstrated that circular RNAs (circRNAs) could be participated in the progression of multifarious diseases, especially plentiful carcinomas. CircAMOTL1 (angiomotin-like1, ID: hsa_circ_0004214), which is located on human chromosome 11:9 4532555-94533477, is involved in the occurrence of breast cancer, etc. However, the intrinsic and concrete molecular mechanism of circAMOTL1 in cervical carcinomas remained thoroughly unclear, which was also the bottleneck of circRNAs studies in cancer.

Methods

The relative expression levels of circAMOTL1 and miR-526b in cervical carcinoma patients’ specimens and cervical carcinoma cell lines were detected by RT-qPCR. Through experiments including loss-function and overexpression, the biological effects of circAMOTL1 and miR-526b on the proliferation, migration, apoptosis, and tumorigenicity were explored in cervical carcinomas. Dual luciferase reporter gene analysis, western blot, and other methods were adopted to explore the circAMOTL1 potential mechanism in cervical carcinomas.

Results

In our experiments, our researches displayed that circAMOTL1 was significantly higher expression in cervical carcinomas specimens and cell lines. Further experiments illustrated that the knockdown of circAMOTL1 could restrain the malignant phenotype, AKT signaling, and epithelial–mesenchymal transition (EMT) of in cervical carcinomas cells. Meanwhile miR-526b was downregulated in cervical carcinomas and even miR-526b could partially reverse circAMOTL1 function in malignant cervical tumor cells. CircAMOTL1 acts as a microRNA (miRNA) sponge that actively regulates the expression of salt-inducible kinase 2 (SIK2) to sponge miR-526b and subsequently increases malignant phenotypes of cervical carcinomas cells. In a word, circAMOTL1 acts a carcinogenic role and miR-526b serves as the opposite function of antioncogene in the cervical carcinoma pathogenesis.

Conclusion

CircAMOTL1-miR-526b-SIK2 axis referred to the malignant progression and development of cervical carcinomas. CircAMOTL1 expression was inversely correlated with miR-526b and positively correlated with SIK2 mRNA in cervical cancer tissues. Thus, circAMOTL1 exerted an oncogenic role in cervical cancer progression through sponging miR-526b. Taken together, our study revealed that circAMOTL1 acted as an oncogene and probably was a potential therapeutic target for the cervical cancer.

LncRNA PVT1 accelerates malignant phenotypes of bladder cancer cells by modulating miR-194-5p/BCLAF1 axis as a ceRNA

Background: Numerous studies proved that long non-coding RNA (lncRNA) is involved in the progression of multifarious diseases, especially in some carcinomas. As a potential tumor biomarker, plasmacytoma variant translocation 1 gene (PVT1) is involved in the development and progression of multifarious cancers. Nevertheless, the intrinsic and concrete molecular mechanism of PVT1 in bladder cancer still remained unclear, which is also the dilemma faced in many non-coding RNA studies.

Results: Our research revealed that PVT1 was significantly higher expression in bladder carcinoma specimens and cell lines. Further experiments indicated that knockdown or overexpression of PVT1 restrained or promoted the malignant phenotype and WNT/β-catenin signaling in bladder cancer cells. Meanwhile miR-194-5p was in contrast and miR-194-5p could partially reverse the function of PVT1 in malignant bladder tumor cells. As a microRNA sponge, PVT1 actively promotes the expression of b-cells lymphoma-2-associated transcription factor 1 (BCLAF1) to sponge miR-194-5p and subsequently increases malignant phenotypes of bladder cancer cells. Therefore, it performs a carcinogenic effect and miR-194-5p as the opposite function, and serves as an antioncogene in the bladder carcinomas pathogenesis.

Conclusion: PVT1-miR-194-5p-BCLAF1 axis is involved in the malignant progression and development of bladder carcinomas. Experiments revealed that PVT1 has a significant regulatory effect on bladder cancer (BC) and can be used as a clinical diagnostic marker and a therapeutic molecular marker for patients suffering from BC.

Methods: In urothelial bladder carcinoma specimens and cell lines, the relative expression levels of PVT1 and miR-194-5p were detected by quantitative reverse transcription PCR (RT-qPCR). Through experiments such as loss-function and over-expression, the biological effects of PVT1 and miR-194-5p on the proliferation, migration, apoptosis and tumorigenicity were explored in bladder cancer cells. Co-immunoprecipitation, proteomics experiments, dual luciferase reporter gene analysis, western blot and other methods were adopted to investigate the PVT1 potential mechanism in bladder carcinomas.

Long non-coding RNA CCAT2 promotes prostate cancer cell proliferation and invasion by regulating the Wnt/β-catenin signaling pathway

Long non-coding RNA colon cancer associated transcript 2 (CCAT2) is dysregulated in a number of different types of human cancer, and affects cancer progression via the Wnt/β-catenin signaling pathway. However, the roles of CCAT2 and the Wnt/β-catenin signaling pathway in prostate cancer (PCa) are not completely understood. The present study aimed to investigate the potential mechanism of CCAT2 in PCa. In the present study, the reverse transcription-quantitative PCR (RT-qPCR) results indicated that CCAT2 expression was significantly upregulated in PCa tissues, and DU145 and PC3 cell lines compared with normal prostate tissues and the epithelial RWPE-1 cell line, respectively. Functional assays indicated that CCAT2 downregulation inhibited DU145 and PC3 cell proliferation, cell cycle, migration and invasion. In addition, the luciferase reporter assay, RT-qPCR and western blotting results indicated that CCAT2 regulated transcription factor 7 like 2 (TCF7L2) expression by binding to microRNA-217. Further western blotting and TOPFlash assays indicated that CCAT2-knockdown inhibited the Wnt/β-catenin signaling pathway in DU145 and PC3 cell lines by inhibiting the expression of TCF7L2. However, CCAT2-knockdown-mediated effects were reversed by the Wnt/β-catenin signaling pathway activator lithium chloride (LiCl). Further cell experiments suggested that LiCl treatment reversed CCAT2-knockdown-mediated inhibition of PCa cell proliferation, cell cycle, epithelial-mesenchymal transition, migration and invasion. Overall, the results indicated that CCAT2 regulated PCa via the Wnt/β-catenin signaling pathway; therefore, CCAT2 may exhibit key role during the progression of PCa and may serve as a therapeutic target for the disease.

Long non-coding RNA UCA1 promotes malignant phenotypes of renal cancer cells by modulating the miR-182-5p/DLL4 axis as a ceRNA

Background

Accumulating literatures have indicated that long non-coding RNAs (lncRNAs) are potential biomarkers that play key roles in tumor development and progression. Urothelial cancer associated 1 (UCA1) is a novel lncRNA that acts as a potential biomarker and is involved in the development of cancers. However, the molecular mechanism of UCA1 in renal cancer is still needed to further explore.

Methods

The relative expression level of UCA1 was determined by Real-Time qPCR in a total of 88 patients with urothelial renal cancer and in different renal cancer cell lines. Loss-of-function experiments were performed to investigate the biological roles of UCA1 and miR-182-5p on renal cancer cell proliferation, migration, apoptosis and tumorigenicity. Comprehensive transcriptional analysis, dual-luciferase reporter assay and western blot etc. were performed to explore the molecular mechanisms underlying the functions of UCA1.

Results

In this study, we found that UCA1 was significantly up-regulated in renal cancer. Moreover, increased UCA1 expression was positively correlated with differentiation and advanced TNM stage. Further experiments demonstrated that knockdown of UCA1 inhibited malignant phenotypes and Notch signal path of renal cancer cells, and miR-182-5p was reverse function as UCA1. UCA1 functioned as a miRNA sponge to positively regulate the expression of Delta-like ligand 4(DLL4) through sponging miR-182-5p and subsequently promoted malignant phenotypes of renal cancer cells, thus UCA1 playing an oncogenic role and miR-182-5p as an antioncogenic one in renal cancer pathogenesis.

Conclusion

UCA1-miR-182-5p-DLL4 axis is involved in proliferation and progression of renal cancer. Thus, this study demonstrated that UCA1 plays a critical regulatory role in renal cancer cell and UCA1 may serve as a potential diagnostic biomarker and therapeutic target of renal cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-020-1132-x.

LncRNAs act as prognostic biomarkers in bladder carcinoma: A meta-analysis

Background and purpose

Increasing studies have shown that different kinds of lncRNAs play key role in the development of multiple carcinomas. Therefore, we conducted a meta-analysis to investigate an association between the expression level of lncRNAs and the prognosis of bladder cancer (death or other clinical outcomes).

Methods

A systematic literature search was performed by using PubMed. Twenty-four studies were included in the meta-analysis based on the inclusion and exclusion criteria. In total, there are 1652 independent participants.

Results

The result showed that high expression levels of lncRNAs were demonstrated to be associated with poor overall survival (OS) (HR = 2.33, 95%CI: 1.51–2.39, p < 0.01) in bladder carcinoma, but there was no significant correlation between lncRNAs level and recurrence-free survival (RFS) (pooled HR = 1.57, 95%CI 0.69–3.56, p = 0.284), and progression-free survival (PFS) (pooled HR = 1.37, 95%CI 0.79–2.38, p = 0.269). Additionally, increased lncRNAs expression was found to be moderately correlated with tumor stage and progression (II/III/IV vs. I, OR = 3.20, 95%CI: 1.72–5.98, p < 0.001). In addition, elevated lncRNAs expression predicted lymph node metastasis (LNM) significantly (pooled OR = 2.29, 95 % CI 1.33–3.95, p < 0.01). No significant heterogeneity was observed among studies except lymph node metastasis.

Conclusion

In conclusion, high expression levels of lncRNAs were demonstrated to be associated with poor OS and positive LNM, and lncRNAs might be potential prognostic markers in bladder cancer.

Colon Cancer-Associated Transcripts 1 and 2: Roles and functions in human cancers

The long noncoding RNAs (lncRNAs) Colon Cancer-Associated Transcripts 1 and 2 (CCAT1 and CCAT2) are located in a recurrently amplified region in cancers. Their proximity with the Myc oncogene and their interactions with its promoter provided further evidence for their contribution in the tumorigenesis processes. Several cell line and clinical studies have shown upregulation of these lncRNAs in diverse malignancies. Moreover, some single nucleotide variants within these genes have been associated with cancer risk or therapeutic response in different populations. Besides, these two lncRNAs act as sponges for some tumor suppressor microRNAs (miRNAs), thus promoting cancer evolution. In the current study, we review recent literature about their expression level, interaction with cancer-related pathways, their role in determination of cell fate and their contribution in malignant phenotype characteristics. Taken together, the current literature shows that these lncRNAs are putative targets for design of novel treatment strategies. Moreover, their expression levels in biopsied samples, exosomes, and sera of patients might be applied as diagnostic biomarkers or markers for patient follow-up.

Long noncoding RNA HOTTIP is associated with male infertility and promotes testicular embryonal carcinoma cell proliferation

Background

It has been proposed that lncRNAs, widely transcribed from genomes, play pivotal regulatory roles in a variety of biological processes, but their function in regulating spermatogenesis in human males is rarely reported.

Methods

QRT‐PCR was adopted to detect HOTTIP expression level in testicular tissues from hypospermatogenesis (Hypo) patients or controls. The proliferation levels of NT2 and 293T were measured via CCK‐8 and EdU detection. Meanwhile, luciferase reporter gene assay and bioinformatics analysis were carried out to identify a target of HOTTIP. Additionally, the underlying mechanism of HOTTIP’s function was investigated using western blotting and RIP analysis.

Results

The research results manifested that the expression of HOTTIP in testicular tissues from Hypo patients was prominently reduced in comparison with that in control testicular tissues. Interestingly, it was noted that HOTTIP exhibited a high expression in testicular embryonal carcinoma cell line NT2 compared with that in normal control cell line 293T. It was denoted in cell function evaluation that cell proliferation was impeded by downregulated HOTTIP but evidently stimulated by overexpressed HOTTIP. Moreover, HOTTIP was capable of positively modulating HOXA13 expression via the competitive binding to miR‐128‐3p.

Conclusion

Therefore, HOTTIP acting as ceRNAs to promote testicular embryonal carcinoma cell proliferation.

Long Non-coding Ribonucleic Acid as a Novel Diagnosis and Prognosis Biomarker of Bladder Cancer

Long non-coding ribonucleic acids (lncRNAs) are the largest group of non-coding RNAs and supposedly have a broad spectrum of diverse functions in normal cellular processes. This study was carried out to review the biological functions of candidate lncRNAs (i.e., H19, MALAT-1, TUG1, UCA-1, MEG-3, HOTAIR, CCAT2, AATBC, and the like) with aberrant expressions that play critical roles in bladder cancer (BC) initiation, progression, and metastasis. A formal narrative review was performed by searching the PubMed database for English articles using a combination of keywords such as "long non-coding RNA", "lncRNA", "cancer", "bladder cancer", "screening", "prognosis", "diagnosis", and "response to therapy". In addition, the existing literature was studied on biological function, aberrant expression, and the clinical applications of candidate lncRNAs in BC. By a better understanding of the molecular mechanisms of lncRNAs, they can be used as biomarkers for tumor signatures in urologic malignancies, which can improve screening, prognosis, diagnosis, and the treatment of BC.

Long noncoding RNA CCAT2 functions as a competitive endogenous RNA to regulate FOXC1 expression by sponging miR-23b-5p in lung adenocarcinoma

Long noncoding RNA (lncRNA) may regulate the process of tumor formation. Although lncRNA CCAT2 has been identified as a key point in many diseases, its pathophysiological mechanism in lung adenocarcinoma remains unknown. We measured the expression level of CCAT2 in lung adenocarcinoma cells and normal lung epithelial cell line BEAS-2B by quantitative real-time polymerase chain reaction (qRT-PCR). As well, cell migration and proliferation were detected by transwell detection and CCK8 assay. At the same time, the new target point of CCAT2 was confirmed with bioinformatics analysis and dual-luciferase reporter assay. In addition, potential mechanisms were studied by Western blot analysis and RNA immunoprecipitation (RIP) analysis. The expression of CCAT2 was upregulated obviously in lung adenocarcinoma cells. Cell function analysis showed that upregulation of CCAT2 significantly promoted cell proliferation and migration, and reduction of CCAT2 inhibited cell migration and proliferation. In addition, CCAT2 positively regulated the expression of FOXC1 by competitive binding with miR-23b-5p. These findings indicated that CCAT2 may act as a competitive endogenous RNA (ceRNA) to regulate FOXC1 expression by competitively binding miR-23b-5p in lung adenocarcinoma.

Epigenomics of Pancreatic Cancer: A Critical Role for Epigenome-Wide Studies

Several challenges present themselves when discussing current approaches to the prevention or treatment of pancreatic cancer. Up to 45% of the risk of pancreatic cancer is attributed to unknown causes, making effective prevention programs difficult to design. The most common type of pancreatic cancer, pancreatic ductal adenocarcinoma (PDAC), is generally diagnosed at a late stage, leading to a poor prognosis and 5-year survival estimate. PDAC tumors are heterogeneous, leading to many identified cell subtypes within one patient’s primary tumor. This explains why there is a high frequency of tumors that are resistant to standard treatments, leading to high relapse rates. This review will discuss how epigenetic technologies and epigenome-wide association studies have been used to address some of these challenges and the future promises these approaches hold.

LncRNA as a diagnostic and prognostic biomarker in bladder cancer: a systematic review and meta-analysis

Background

Bladder cancer is one of the most common urinary malignancies, and has a high recurrence rate and poor outcomes. In order to identify novel diagnostic and prognostic biomarkers for bladder cancer, we conducted a meta-analysis to analyze the association between long non-coding RNA (lncRNA) expression and survival in bladder cancer.

Materials and methods

We searched literature from databases using our inclusion and exclusion criteria. STATA 14.0 software was used to analyze the data from collected studies and to construct the forest plots. A different effect size was selected for each meta-analysis.

Results

After selection, 30 articles were found to be eligible. The present meta-analysis contains data from 13 articles about clinicopathological characteristics, six articles about diagnosis, and 16 articles about prognosis. In the present study, we found that many lncRNAs could function as potential diagnostic and prognostic markers in bladder cancer. Among these findings, UCA1 was expected to be a diagnostic biomarker for bladder cancer, while the aberrant expression of HOTAIR and GAS5 was associated with poor disease-free survival/recurrence-free survival/disease-specific survival.

Conclusion

Overall, the present study is the first meta-analysis to assess the association between expression of lncRNAs and clinical value in patients with bladder cancer. LncRNAs hold promise as novel diagnostic and prognostic markers in bladder cancer.

Long noncoding RNAs: regulation, function and cancer

Long noncoding RNAs (lncRNAs) are non-protein-coding RNA transcripts that exert a key role in many cellular processes and have potential toward addressing disease etiology. Here, we review existing noncoding RNA classes and then describe a variety of mechanisms and functions by which lncRNAs regulate gene expression such as chromatin remodeling, genomic imprinting, gene transcription and post-transcriptional processing. We also examine several lncRNAs that contribute significantly to pathogenesis, oncogenesis, tumor suppression and cell cycle arrest of diverse cancer types and also give a summary of the pathways that lncRNAs might be involved in.

Long non-coding RNA expression in bladder cancer

The advent of novel high-throughput sequencing methods has facilitated identification of non-coding RNAs with fundamental roles in cellular biological and pathological conditions. A group of these consisting of at least 200 nucleotides are called long non-coding RNAs (lncRNAs). Their participation in the pathogenesis of cancer has been highlighted in recent years. Bladder cancer, one of the most prevalent cancers worldwide, exhibits altered expression levels of several lncRNAs. Several in vitro and in vivo studies have assessed the effects of silencing RNAs on cancer cell phenotypes and in vivo tumor growth. For instance, in vitro studies have shown that nuclear paraspeckle assembly transcript 1 (NEAT1), promoter of CDKN1A antisense DNA damage-activated RNA(PANDAR) and metastasis-associated lung adenocarcinoma transcript 1(MALAT1) have oncogenic effects while Maternally expressed 3 (MEG3) and BRAF activated non-coding RNA (BANCR) are tumor suppressors. Analysis of these data will help to identify a panel of lncRNAs that can be potentially used for both early detection and prognosis in bladder cancer patients. Here, we review the roles of several lncRNAs in the oncogenesis, tumor suppression, early detection, and prognosis of bladder cancer.

Highly expressed long non-coding RNA CRNDE promotes cell proliferation through PI3K/AKT signalling in non-small cell lung carcinoma

Recently, numerous studies have revealed that long non-coding RNAs (lncRNAs) play complex roles in various lung diseases, while the colorectal neoplasia differentially expressed (CRNDE) functions in non-small cell lung carcinomas (NSCLC) remain largely unknown. In the present study, we investigate the role and mechanism of CRNDE in the progression of NSCLC. The mRNA level of CRNDE in NSCLC patients and cells was detected by qRT-PCR. The influence of CRNDE silencing or over-expression on NSCLC cell proliferation and growth were assessed by MTT and flow cytometry, respectively. We also investigated the effect of abnormal CRNDE expression on cyclins and PI3K/AKT pathway. Furthermore, si-CRNDE NSCLC cell lines were injected subcutaneously into nude mice to explore tumour formation in vivo. The expression of CRNDE was significantly upregulated in NSCLC patients and cells. In addition, both loss and gain function assays revealed that CRNDE promoted NSCLC cell proliferation and growth both in vitro and in vivo. Moreover, CRNDE regulated the cell cycle transition from G₀ /G₁ stage to S stage and modulated the expression of CDK4, CDK6 and CCNE1. We further illustrated that CRNDE activated PI3K/AKT signalling in NSCLC cell lines. In conclusion, CRNDE was highly expressed in NSCLC malignant tissues and the heightened CRNDE strongly promoted NSCLC cell proliferation and growth through activating PI3K/AKT signalling; our results shed a light on utilizing CRNDE as a potential novel therapeutic target for the treatment of NSCLC.

Long non-coding RNA CRNDE promotes gallbladder carcinoma carcinogenesis and as a scaffold of DMBT1 and C-IAP1 complexes to activating PI3K-AKT pathway

Deleted in malignant brain tumors 1 (DMBT1) is deleted during cancer progression and as a potential tumor-suppressor gene in various types of cancer. However, its role in Gallbladder cancer remains poorly understood. DMBT1 has low-expression and deletion of copy number were detected in normal tissues and GBC cancer tissues by qRT-PCR. Knockdown of DMBT1 increased migration and invasion and overexpressed DMBT1 impaired migration and invasion in GBC cells. We also evaluated the molecular mechanism of DMBT1 by RNA sequencing and GSEA analysis. RNA-Pulldown and RIP assay authenticated CRNDE can specified binding with DMBT1 and c-IAP1. Downregulation of DMBT1 resulted in significant change of gene expression (at least 2-fold) in PI3K-AKT pathway, increased expression of MMP-9, JUK-1, ERK and AKT, activating PI3K-AKT pathway lead to GBC carcinogenesis.We for the first time reported, DMBT1 as a prognosis biomarker, is low-expressed in GBC tumors, and CRNDE act as a scaffold to recruit the DMBT1 and c-IAP1, promotes the PI3K-AKT pathway. Our study reveals DMBT1 may be an important contributor to GBC cancer development.

Overexpression of CRNDE promotes the progression of bladder cancer

Accumulating evidences indicate that long non-coding RNAs (lncRNAs) are indispensable in cancer initiation and progression. Dysregulation of functional lncRNAs can promote the development of cancers. Previous research have revealed that augmented expression of CRNDE caused poor prognosis of cancer patients and facilitate the tumor progress in various cancers. Nevertheless, the underlying roles of CRNDE in bladder cancer progression are not entirely clear. To further identify the effects CRNDE in bladder cancer progression, we performed the gain and loss of function assay. In this work, we have presented evidence that CRNDE was significantly increased in bladder cancer, and overexpressed expression of CRNDE was positively related with advanced TNM stage of bladder cancer patients. In addition, in vitro experiments showed that CRNDE strengthened cell migration/proliferation and inhibited cell apoptosis in bladder cancer. To sum up, our results exhibited new understand into the role of lncRNA CRNDE in the development of bladder cancer.

AFAP1-AS1: A novel oncogenic long non-coding RNA in human cancers

Long non-coding RNAs (lncRNAs), a group of non-protein-coding RNAs with more than 200 nucleotides in length, are involved in multiple biological processes, such as the proliferation, apoptosis, migration and invasion. Moreover, numerous studies have shown that lncRNAs play important roles as oncogenes or tumour suppressor genes in human cancers. In this paper, we concentrate on actin filament-associated protein 1-antisense RNA 1 (AFAP1-AS1), a well-known long non-coding RNA that is overexpressed in various tumour tissues and cell lines, including oesophageal cancer, pancreatic ductal adenocarcinoma, nasopharyngeal carcinoma, lung cancer, hepatocellular carcinoma, ovarian cancer, colorectal cancer, biliary tract cancer and gastric cancer. Moreover, high expression of AFAP1-AS1 was associated with the clinicopathological features and cancer progression. In this review, we sum up the current studies on the characteristics of AFAP1-AS1 in the biological function and mechanism of human cancers.

Long non-coding PANDAR as a novel biomarker in human cancer: A systematic review

OBJECTIVES

Long non-coding RNAs (lncRNAs) are characterized as a group of RNAs that more than 200 nucleotides in length and have no protein-coding function. More and more evidences provided that lncRNAs serve as key molecules in the development of cancer. Deregulation of lncRNAs functions as either oncogenes or tumour suppressor genes in various diseases. Recently, increasing studies about PANDAR in cancer progression were reported. In our review, we will focus on the current research on the character of PANDAR include the clinical management, tumour progression and molecular mechanisms in human cancers.

MATERIALS AND METHODS

We summarize and analyze current studies concerning the biological functions and mechanisms of lncRNA PANDA in tumour development. The related studies were obtained through a systematic search of Pubmed.

RESULTS

PANDAR was a well-characterized oncogenic lncRNA and widely overexpressed in many tumours. PANDAR is upregulated in many types of cancer, including colorectal cancer, lung cancer, renal cell carcinoma, cholangiocarcinoma, osteosarcoma, thyroid cancer and other cancers. Upregulation of PANDAR was significantly associated with advanced tumour weights, TNM stage and overall survival. Furthermore, repressed of PANDAR would restrain proliferation, migration and invasion.

CONCLUSION

PANDAR may act as a powerful tumour biomarker for cancer diagnosis and treatment.

CCAT2 is an oncogenic long non-coding RNA in pancreatic ductal adenocarcinoma

Background

Pancreatic ductal adenocarcinoma (PDAC) is highly aggressive with poor prognosis. Long non-coding RNAs (lncRNAs), a group of non-coding RNAs, play important roles in the progression of PDAC. This study aimed to investigate the potential involvement of lncRNA CCAT2 in PDAC tumorigenesis.

Methods

Expression of CCAT2 was detected by quantitative real-time PCR (qRT-PCR) in 80 human PDAC tissues and three PDAC cell lines. The effects of CCAT2 silencing in PANC-1 cells on cell proliferation and invasion were studied using MTT assay and transwell assay, respectively. The effect of CCAT2 silencing on tumorigenesis was assessed by PANC-1 xenograft in vivo. Using si-KRAS, the role of KRAS to regulate CCAT2 was evaluated by qRT-PCR and luciferase reporter assay. The involvement of MEK/ERK and PI3K/AKT signaling in CCAT2 regulation was investigated by pathway inhibitors PD98059 and LY294002, respectively.

Results

CCAT2 was significantly elevated in high-grade PDAC tissues and higher CCAT2 expression was correlated with lower survival rate in PDAC patients. CCAT2 was up-regulated in PDAC cell lines, as compared with normal pancreatic cells. Silencing of CCAT2 inhibited cell proliferation and invasion in PANC-1 cells in vitro, and attenuated tumorigenesis of PANC-1 xenograft in vivo. Furthermore, CCAT2 was regulated by KRAS through MEK/ERK signaling pathway.

Conclusions

CCAT2 is an oncogenic lncRNA in PDAC likely regulated by the KRAS-MEK/ERK pathway. It could be a potential diagnostic biomarker and therapeutic target for PDAC.

The Function and Mechanism of Long Non-coding RNA-ATB in Cancers

Long non-coding RNAs (lncRNAs) are a class of transcriptional RNA molecules with a length of greater than 200 nucleotides that function as regulatory factors in many human diseases. Studies have shown that lncRNAs are involved in multiple cellular processes, including proliferation, apoptosis, migration, and invasion. In this report, a long non-coding RNA-ATB that is overexpressed in various tumor tissues and cell lines was investigated. Recent evidence suggests that ATB is dysfunctional in a variety of cancers, including hepatocellular carcinoma, gastric cancer (GC), colorectal cancer (CRC), breast cancer (BC), prostate cancer, renal cell carcinoma, non-small cell lung cancer (NSCLC), pancreatic cancer, osteosarcoma, and glioma. The high expression of ATB is associated with clinicopathological features of cancer patients. In addition, overexpression of lncRNA-ATB can promote tumor proliferation, migration, and invasion. LncRNA-ATB induces epithelial-mesenchymal transition (EMT) by competitively binding to miRNAs, thus promoting tumor progression. Biological functions and mechanisms of ATB in human cancers are discussed here, concluding that lncRNA-ATB may provide a new biomarker for use in diagnosis and prognosis of cancer.

mRNA, microRNA and lncRNA as novel bladder tumor markers

Early detection of bladder cancer (BC) is essential for improvement of the patient's prognosis and general survival rates. Current diagnostic methods are still limited, so new specific and cost-effective biomarkers are emerging as the noninvasive tools in treatment decisions in recurrent BC. Gene expression and epigenetic profile can be analysed using quantitative real-time-PCR (qRT-PCR) method in urine, blood and tissue. This review provides an update of recent findings on BC molecular profile as novel markers in diagnosis and prognosis of bladder tumors. We describe mRNA-, microRNA- and lncRNA-based biomarkers involved in the BC detection, diagnosis, prediction of recurrence and monitoring after treatment.

Silencing CCAT2 inhibited proliferation and invasion of epithelial ovarian carcinoma cells by regulating Wnt signaling pathway

Long non-coding RNA CCAT2 (colon cancer-associated transcript 2) is dysregulated in varieties of human tumors. However, the role of CCAT2 in epithelial ovarian carcinoma (EOC) is not yet known clearly. The aim of this study is to investigate the effects of CCAT2 on proliferation and invasion of EOC cells and the potential mechanisms by which CCAT2 functions. In the present paper, we found that knockdown of CCAT2 impaired cell proliferation and invasion in vitro. Furthermore, we also studied the role of CCAT2 in the modulation of Wnt/β-catenin signaling pathway. Our results showed that knockdown of CCAT2 inhibited the expression of β-catenin and the activity of TCF/LEF (T-cell factor/lymphoid enhancer factor) acting as a key transcription factor of Wnt/β-catenin signaling pathway. In addition, we found that silencing CCAT2 down-regulated the expression of c-MYC and MMP-7. But, that was reversed by the treatment with LiCl (lithium chloride) which could activate canonical Wnt/β-catenin signaling pathway. Taken together, these results indicate that CCAT2 may promote ovarian cancer progression, at least partly, through Wnt/β-catenin signaling pathway. Thus, CCAT2 might represent a novel therapeutic target for ovarian cancer.

The regulatory roles of long non-coding RNAs in the development of chemoresistance in breast cancer

Chemoresistance is one of the major hurdles in the treatment of breast cancer, which limits the effect of both targeted and conventional therapies in clinical settings. Therefore, understanding the mechanisms underpinning resistance is paramount for developing strategies to circumvent resistance in breast cancer patients. Several published reports have indicated that lncRNAs play a dynamic role in the regulation of both intrinsic and acquired chemoresistance through a variety of mechanisms that endow cells with a drug-resistant phenotype. Although a number of lncRNAs have been implicated in chemoresistance of breast cancer, their mechanistic roles have not been systematically reviewed. Thus, here we present a detailed review on the latest research findings and discoveries on the mechanisms of acquisition of chemoresistance in breast cancer related to lncRNAs, and how lncRNAs take part in various cancer signalling pathways involved in breast cancer cells. Knowledge obtained from this review could assist in the development of new strategies to avoid or reverse drug resistance in breast cancer chemotherapy.

BANCR: a novel oncogenic long non-coding RNA in human cancers

Long non-coding RNAs account for large proportion of non-coding transcripts in human genomes. Though they lack of open reading framework and cannot encode protein, they can control endogenous gene expression though regulating cell life activities. They serve as transcriptional modulator, posttranscriptional processor, chromatin remodeler and splicing regulator during the process of gene modification. Moreover, long non-coding RNAs were regarded as potential tumor markers for cancer diagnosis and prognosis. BANCR was identified as a cancer-promoting long non-coding RNA in melanoma tissues. Since then, increasing studies about BANCR in cancer progression were reported. BANCR was dysregulated in various cancers including melanoma, colorectal cancer, retinoblastoma, lung carcinoma and hepatocellular carcinoma, and increased BANCR expression cause poor prognosis and shorter survival rate of cancer patients. Furthermore, the functions and mechanisms of BANCR in cancer cells have been clarified. Here, we focus on the current research on the role of BANCR in the clinical management, progression and molecular mechanisms in human cancer.

Long non-coding RNAs: a rising biotarget in colorectal cancer

Colorectal cancer (CRC) is a common gastrointestinal cancer, with a high incidence and high mortality. Long non-coding RNAs (lncRNAs) are involved in the development, invasion and metastasis, early diagnosis, prognosis, the chemoresistance and radioresistance of CRC through interference with mRNA activity, directly combining with proteins to regulate their activity or alter their localization, influencing downstream gene expression by inhibiting RNA polymerase and regulating gene expression as competing endogenous RNAs. Recent progress in next generation sequencing and transcriptome analysis has revealed that tissue and cancer-type specific lncRNAs could be useful prognostic markers. Here, the CRC-associated lncRNAs from recent studies until October 2016 are reviewed and multiple studies that have confirmed CRC-associated lncRNAs are summarized. This review may be helpful in understanding the overall relationships between the lncRNAs involved in CRC.

Rosiglitazone induces apoptosis on human bladder cancer 5637 and T24 cell lines

Rosiglitazone is a synthetic ligand of peroxisome proliferator-activated receptor γ (PPARγ), and it can induce apoptosis and autophagy in a variety of cancer cells. In the present study, we aimed to investigate the influence of rosiglitazone on the proliferation and apoptosis of the 5637 and T24 human bladder cancer cell lines. The results demonstrated that the level of growth inhibition rate was gradually increased by treating the 5637 and T24 cells with higher doses of rosiglitazone and longer incubation time. Rosiglitazone exerted a potent inhibiting effect on migration of the 5637 and T24 cell lines. Moreover, rosiglitazone exerted a antineoplastic activity by inducing apoptosis and cell cycle arrest. Furthermore, treatment with rosiglitazone led to decrease the anti-apoptotic protein Bcl-2 level and increase the pro-apoptotic protein caspase 3 level in 5637 and T24 cells. Importantly, the protein expression of PPAR γ was significantly increased in the present of rosiglitazone in 5637 and T24 cells as compared to control group. In conclusion, the present study demonstrates that rosiglitazone has a potential antineoplastic activity in human bladder cancer cell lines, and the underlying mechanism was mediated, at least partially, through regulation of apoptosis-related protein and PPAR γ expression.

Colon cancer associated transcripts in human cancers

Long non-coding RNAs serve as important regulators in complicated cellular activities, including cell differentiation, proliferation and death. Dysregulation of long non-coding RNAs occurs in the formation and progression of cancers. The family of colon cancer associated transcripts, long non-coding RNAs colon cancer associated transcript-1 and colon cancer associated transcript-2 are known as oncogenes involved in various cancers. Colon cancer associated transcript-1 is a novel lncRNA located in 8q24.2, and colon cancer associated transcript-2 maps to the 8q24.21 region encompassing rs6983267. Colon cancer associated transcripts have close associations with clinical characteristics, such as lymph node metastasis, high TNM stage and short overall survival. Knockdown of them can reverse the malignant phenotypes of cancer cells, including proliferation, migration, invasion and apoptosis. Moreover, they can increase the expression level of c-MYC and oncogenic microRNAs via activating a series of complex mechanisms. In brief, the family of colon cancer associated transcripts may serve as potential biomarkers or therapeutic targets for human cancers.

Silencing of long non-coding RNA CCAT2 depressed malignancy of oral squamous cell carcinoma via Wnt/β-catenin pathway

Oral squamous cell carcinoma is a common and lethal malignancy affecting the head and neck region. CCAT2 (colon cancer-associated transcript 2) gene is affiliated with long non-coding RNAs, which are often found to have important regulatory roles in cancers. This study aims to assess the expression and clinical significance of CCAT2 gene, identify its malignant biological behaviors, and explore the possible mechanisms in oral squamous cell carcinoma. CCAT2 expression was detected by quantitative real-time polymerase chain reaction, and its relationship with clinical factors was assayed using the Kaplan-Meier survival curve. The biological behaviors of CCAT2 and its potential mechanisms in oral squamous cell carcinoma were explored by the combined use of CCAT2 knockdown technology and the Wnt/β-catenin pathway agonist lithium chloride (LiCl). Our results showed that CCAT2 functioning as a potential oncogene was upregulated in oral squamous cell carcinoma. CCAT2 with high expression level was correlated with poor differentiation, higher T stage, and clinical stage, which made CCAT2 to be a prognostic biomarker in oral squamous cell carcinoma. LiCl-activated Wnt/β-catenin signaling pathway could partly restore the CCAT2-mediated malignant biological behaviors of oral squamous cell carcinoma cells by suppressing β-catenin, CCND1, and MYC and activating glycogen synthase kinase 3 beta expression. These findings might assist in the discovery of novel potential diagnostic and therapeutic target for oral squamous cell carcinoma, thereby improve the effects of clinical treatment in patients.

Tetracycline-controllable artificial microRNA-HOTAIR + EZH2 suppressed the progression of bladder cancer cells

Previous studies have suggested that EZH2 is up-regulated in bladder cancer tissues and identified it as a biomarker for poor prognosis. However, the biological functions of EZH2 in bladder cancer cells remain unknown. In this research, we discovered that EZH2 expression is irrelevant to the TNM stage and poor prognosis of bladder cancer patients. But suppression of EZH2 can slowdown the progression of bladder cancer cells. Moreover, we used the technology of synthetic biology to construct the tetracycline-controllable artificial microRNA-HOTAIR + EZH2, which can decrease the expression of HOTAIR and EZH2 in a doxycycline dosage-dependent manner. And we also found that HOTAIR expression was positively correlated with EZH2 expression. Tetracycline-controllable artificial microRNA-HOTAIR + EZH2 can inhibit the proliferation and migration of bladder cancer cells. Meanwhile, the apoptosis rate of bladder cancer cells was increased. Taken together, our research showed the cancer-promoting effects of EZH2 and created a novel method to rescue the development of bladder cancer cells.

Prognostic and clinicopathological significance of CCAT2 in Chinese patients with various tumors

BACKGROUND

Colon cancer-associated transcript 2 (CCAT2) as a long noncoding RNA (lncRNA) is overexpressed and plays a significant prognostic role in patients with tumors. The present study aimed to comprehensively evaluate the clinical value of CCAT2 in the Chinese population, as a potential prognostic marker in multiple cancers.

METHODS

A systematic search of eligible studies was conducted in the PubMed, Web of Science, Cochrane Library, Wanfang and the China National Knowledge Infrastructure databases as of March 31, 2017. Approximately 1,711 tumor patients from 16 eligible studies were selected. Analyses of the pooled data were performed, and the odds ratio (OR) or hazard ratio (HR) and the 95% confidence interval (95% CI) were calculated and summarized to evaluate the strength of this association using a fixed- or random-effects model.

RESULTS

Overall analyses showed that increased CCAT2 expression was associated with a higher risk of lymph node metastasis (LNM), an increased potential for distant metastasis (DM) and higher clinical stage (p<0.001 for LNM, p = 0.001 for DM, p<0.001 for clinical stage). HR and the 95% CI for overall survival (OS) were assessed to pool the effect size using a fixed-effects model. A significant association was observed between increased CCAT2 expression and poor OS (pooled HR = 1.91, 95% CI, 1.63-2.22, p<0.001).

CONCLUSIONS

These results indicate that CCAT2 is a biomarker to predict tumor progression and a potential prognostic marker in multiple cancers. Additional well-designed clinical studies are needed to validate these findings.

SPRY4-IT1: A novel oncogenic long non-coding RNA in human cancers

Long non-coding RNAs are classified as a kind of RNA, which are longer than 200 nucleotides in length and cannot be translated into proteins. Multiple studies have demonstrated that long non-coding RNAs are involved in various cellular processes, including proliferation, differentiation, cell death, and metastasis. Among numerous long non-coding RNAs, we focus on Sprouty4-Intron 1 (SPRY4-IT1), a well-known long non-coding RNA that is overexpressed in various kinds of tumor tissues and cell lines. Accumulating evidences show that SPRY4-IT1 was dysregulated in various cancers, including melanoma, breast cancer, esophageal squamous cell carcinoma, non-small cell lung cancer, gastric cancer, colon cancer, and hepatocellular carcinoma, and amplification of SPRY4-IT1 was associated with different clinicopathological features of cancer patients. Importantly, SPRY4-IT1 exerts important roles in tumor progression and metastasis. However, detailed molecular mechanisms of SPRY4-IT1 in cancer progression and metastasis were poorly understood. In this review, we have focused on the characteristics of SPRY4-IT1 and illustrated the biological function and mechanism of SPRY4-IT1 in cancer development.

Long Noncoding RNA CCAT2 as a Potential Novel Biomarker to Predict the Clinical Outcome of Cancer Patients: A Meta-Analysis

Background: Colon Cancer-Associated Transcript 2 (CCAT2) has been demonstrated associated with clinical outcomes in various tumors. However, the results from each study were unfortunately insufficient and not completely consistent. Therefore, we conduct a systematic meta-analysis to evaluate the value for a feasible biomarker for metastasis and prognosis.

Methods: A meta-analysis was performed using data obtained through a systematic search of PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure, Wanfang database and VIP database. The pooled odds ratio (OR) and hazard ratio (HR) with 95% Confidence interval (CI ) using random-effect were used to identify the relationship of CCAT2 with clinical outcome of cancer patients. Subgroup analysis and sensitivity analysis were performed.

Results: A total of 867 patients from eight studies were finally included. Patients with high CCAT2 expression underwent an increased risk of lymph node metastasis (LNM) (OR=3.09, 95% CI: 1.53-6.26) and distant metastasis (DM) (OR=7.70, 95% CI: 3.26-18.17). CCAT2 was also significantly correlated with overall survival (OS) (HR=2.19, 95%CI: 1.70-2.82) and progression-free survival (PFS) (HR=2.59, 95% CI: 1.78-3.76). Moderate heterogeneity was observed in meta-analysis for LNM. However, the results remained robust in multiple sensitivity analyses.

Conclusions: High expression of CCAT2 was linked with poor clinical outcome. CCAT2 can serve as a potential molecular marker for prognosis in different types of cancers.

Upregulation of CCAT2 promotes cell proliferation by repressing the P15 in breast cancer

BACKGROUND

Long non-coding RNAs (lncRNAs) are demonstrated to function as modulators of both transcriptional and post-transcriptional regulation in various types of tumors progression. The objective of the study is to investigate the clinical significance and underlying mechanism of Colon cancer associated transcript 2 (CCAT2) involved in breast cancer.

METHODS

QT-PCR was performed to examine the relative expression levels of CCAT2 in breast cancer tissues and adjacent normal tissues. Kaplan-Meier survival curves and log rank test were applied to assess the correlation between CCAT2 expression and the overall survival (OS) time in patients. MTT cell proliferation assay, transwell invasion assay and cell cycle analysis were conducted to detect the cell proliferation and invasion. Western blot analysis, RNA immunoprecipitation (RIP) and Chromatin immunoprecipitation (ChIP) assays were performed to detect the association between CCAT2 and P15. The tumor xenograft in nude mice was performed to evaluate the effect of CCAT2 expression on tumor growth in vivo.

RESULTS

Our results confirmed that CCAT2 expression levels in tumor tissues were markedly increased than that in adjacent normal tissues. Higher CCAT2 expression was found to show a significantly correlation with advanced TNM stage and lymph node metastasis in patients. Kaplan-Meier survival curves and log-rank test showed that higher CCAT2 expression was closely correlated with shorter over survival (OS) time in patients. In vitro, knockdown of CCAT2 showed that cell proliferation and invasion capabilities were suppressed and increased G0-G1 phase cell proportion but reduced S phase cell proportion in MCF-7 and MDA-MB-231 cells. Moreover, when CCAT2 silencing, the cell cycle relative protein CyclinD1, CyclinE1 and CDK4 expression were downregulated, but p15 was up-regulated in MCF-7 and MDA-MB-231 cells. Besides, we confirmed that CCAT2 suppressed the p15 expression level via interacting with EZH2 in breast cancer cells. In vivo, the tumor growth was inhibited after knockdown of CCAT2.

CONCLUSION

Our results indicated that CCAT2 may be a potential prognostic marker and therapeutic target for breast cancer.

Increased lncRNA ABHD11-AS1 represses the malignant phenotypes of bladder cancer

Bladder cancer is one of the most common urothelial tumors worldwide. While there are some progresses on early bladder cancer detection, patients' mortalities have not been changed significantly. So it is important to get further understanding the mechanism involved in the development and progression of bladder cancer. Long non-coding RNAs play important regulatory roles in a variety of biological processes ranging from gene regulation, cellular differentiation to tumorigenesis. Previous literatures reported that lncRNA ABHD11 Antisense RNA 1 (ABHD11-AS1) (Organism: Homo sapiens) was highly expressed in gastric cancer. Inspired by these observations, we hypothesized that ABHD11-AS1 possibly plays an analogous role in human bladder cancer. We first found that ABHD11-AS1 was up-regulated in bladder cancer tissues and cell lines, and ABHD11-AS1 expression level was positively associated with clinicobiological features. Cell proliferation, cell migration and apoptosis were observed by silencing ABHD11-AS1 and overexpression ABHD11-AS1 caused contrary effects. Taken together, these data suggested that ABHD11-AS1 may be an oncogene and a therapeutic target in bladder cancer.