CCAT2, a novel long non-coding RNA in breast cancer: expression study and clinical correlations.
ABSTRACT: The clinical outcome of BC patients receiving the same treatment is known to vary considerably and thus, there is a compelling need to identify novel biomarkers that can select the patients that would benefit most from a given therapy and can predict the clinical outcome. The aim of this study was to determine the prognostic value of CCAT2, a novel long ncRNA recently characterized by our group and overlapping SNP rs6983267, in BC patients. We first evaluated by RT-qPCR and ISH the expression of CCAT2 in normal breast tissue and BC tissue and further analyzed CCAT2 expression in an independent set of 997 primary BC with regard to clinical, histological, pathological and other biological factors. Also, we explored the possibility of CCAT2 adding to the prognostic value of multivariate models that already included the traditional prognostic factors. Finally, we identified in in vitro models the impact of CCAT2 expression and SNP rs6983267 genotype on cell migration and chemoresistance. Our results revealed that although overexpressed in BCs in two out of three sets of patients, and having the highest expression in lymph node negative (LNN) disease, CCAT2 expression levels are informative solely for a subgroup of BC patients, namely for patients with LNP disease that have received adjuvant CMF chemotherapy. For this subgroup high levels of CCAT2 suggest the patients will not benefit from CMF containing adjuvant chemotherapy (shorter MFS and OS). Additionally, we found that CCAT2 upregulates cell migration and downregulates chemosensitivity to 5'FU in a rs6983267-independent manner.
Project description:The impact of HULC rs7763881 on colorectal cancer (CRC) susceptibility is not yet known. Also, the biological function of the cancer-related rs6983267 remains unclear. We investigated the association of these SNPs with the risk of CRC and adenomatous polyps (AP), their correlation with CCAT2 and HULC expression, and the potential of serum CCAT2 and HULC as biomarkers for CRC. 120 CRC patients, 30 AP patients, and 96 healthy controls were included. Genotyping and serum lncRNAs were assayed by qPCR. Studied SNPs were not associated with AP susceptibility. rs6983267 GG was associated with increased CRC risk, whereas rs7763881 AC was protective. rs7763881 and rs6983267 CT haplotype was protective. Serum CCAT2 and HULC were upregulated in CRC and AP patients versus controls and discriminated these groups by ROC analysis. rs6983267 GG and rs7763881 AA patients demonstrated higher serum CCAT2 and HULC compared with GT/TT and AC, respectively. rs6983267 and serum HULC predicted CRC diagnosis among non-CRC groups (AP?+?controls) by multivariate analysis. Studied SNPs or serum long noncoding RNAs weren't correlated with nodal or distant metastasis. In conclusion, rs6983267 and rs7763881 are potential genetic markers of CRC predisposition and correlate with serum CCAT2 and HULC, two novel potential non-invasive diagnostic biomarkers for CRC.
Project description:The cancer-risk-associated rs6983267 single nucleotide polymorphism (SNP) and the accompanying long noncoding RNA CCAT2 in the highly amplified 8q24.21 region have been implicated in cancer predisposition, although causality has not been established. Here, using allele-specific CCAT2 transgenic mice, we demonstrate that CCAT2 overexpression leads to spontaneous myeloid malignancies. We further identified that CCAT2 is overexpressed in bone marrow and peripheral blood of myelodysplastic/myeloproliferative neoplasms (MDS/MPN) patients. CCAT2 induces global deregulation of gene expression by down-regulating EZH2 in vitro and in vivo in an allele-specific manner. We also identified a novel non-APOBEC, non-ADAR, RNA editing at the SNP locus in MDS/MPN patients and CCAT2-transgenic mice. The RNA transcribed from the SNP locus in malignant hematopoietic cells have different allelic composition from the corresponding genomic DNA, a phenomenon rarely observed in normal cells. Our findings provide fundamental insights into the functional role of rs6983267 SNP and CCAT2 in myeloid malignancies.
Project description:<h4>Purpose</h4>Accumulating evidence demonstrates that genetic susceptibility genes can be used as biomarkers to assess sepsis susceptibility, and genetic variation is associated with susceptibility and clinical outcomes in patients with sepsis and inflammatory disease. Although studies have shown that the lncRNA <i>CCAT2</i> is involved in inflammatory diseases, it remains unclear whether <i>CCAT2</i> gene polymorphisms are associated with susceptibility to inflammatory diseases, such as sepsis, in children.<h4>Methods</h4>We genotyped the rs6983267 <i>CCAT2</i> polymorphism in 474 cases (pediatric sepsis) and 678 controls using TaqMan methods, and odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the strength of associations.<h4>Results</h4>Our results indicate that the rs6983267 T > G polymorphism is significantly associated with an increased risk of sepsis in children (TG and TT: adjusted OR = 1.311, 95% CI = 1.016-1.743, GG and TT: adjusted OR = 1.444, 95% CI = 1.025-2.034 dominant model: GG/TG vs TT adjusted OR = 1.362, 95% CI = 1.055-1.756). Furthermore, the risk effect was more pronounced in children younger than 60 months who were male and who had sepsis.<h4>Conclusion</h4>We found that the <i>CCAT2</i> gene polymorphism rs6983267 T > G may be associated with an increased risk of pediatric sepsis in southern China. A larger multicenter study should be performed to confirm these results.
Project description:The cancer-risk associated rs6983267 single nucleotide polymorphism (SNP) and the accompanying long non-coding RNA CCAT2 in the highly amplified 8q24.21 region has been implicated in cancer predisposition, though causality has not been established. Here, using allele-specific CCAT2 transgenic mice, we demonstrate that CCAT2 overexpression leads to spontaneous myeloid malignancies. CCAT2 is overexpressed in bone marrow and peripheral blood of myelodysplastic/myeloproliferative neoplasms (MDS/MPN) patients. CCAT2 induces global deregulation of gene expression by downregulating EZH2 in vitro and in vivo in an allele-specific manner. We also identified a novel disease-specific RNA mutation (named DNA-to-RNA allelic imbalance, DRAI) at the SNP locus in MDS/MPN patients and CCAT2-transgenic mice. The RNA transcribed from the SNP locus in malignant hematopoietic cells have different allelic composition from the corresponding genomic DNA, a phenomenon rarely observed in normal cells. Our findings provide fundamental insights into the functional role of rs6983267 SNP and CCAT2 in myeloid malignancies. We performed genome-wide microarray expression profiling to study the genetic landscape alterations induced by CCAT2 and DRAI
Project description:The functional roles of SNPs within the 8q24 gene desert in the cancer phenotype are not yet well understood. Here, we report that CCAT2, a novel long noncoding RNA transcript (lncRNA) encompassing the rs6983267 SNP, is highly overexpressed in microsatellite-stable colorectal cancer and promotes tumor growth, metastasis, and chromosomal instability. We demonstrate that MYC, miR-17-5p, and miR-20a are up-regulated by CCAT2 through TCF7L2-mediated transcriptional regulation. We further identify the physical interaction between CCAT2 and TCF7L2 resulting in an enhancement of WNT signaling activity. We show that CCAT2 is itself a WNT downstream target, which suggests the existence of a feedback loop. Finally, we demonstrate that the SNP status affects CCAT2 expression and the risk allele G produces more CCAT2 transcript. Our results support a new mechanism of MYC and WNT regulation by the novel lncRNA CCAT2 in colorectal cancer pathogenesis, and provide an alternative explanation of the SNP-conferred cancer risk.
Project description:Up-regulation of long non-coding RNAs (lncRNAs), colon-cancer associated transcript (CCAT) 1 and 2, was associated with worse prognosis in colorectal cancer (CRC). Nevertheless, their role in predicting metastasis in early-stage CRC is unclear. We measured the expression of CCAT1, CCAT2 and their oncotarget, c-Myc, in 150 matched mucosa-tumour samples of early-stage microsatellite-stable Chinese CRC patients with definitive metastasis status by multiplex real-time RT-PCR assay. Expression of CCAT1, CCAT2 and c-Myc were significantly up-regulated in the tumours compared to matched mucosa (p?<?0.0001). The expression of c-Myc in the tumours was significantly correlated to time to metastasis [hazard ratio?=?1.47 (1.10-1.97)] and the risk genotype (GG) of rs6983267, located within CCAT2. Expression of c-Myc and CCAT2 in the tumour were also significantly up-regulated in metastasis-positive compared to metastasis-negative patients (p?=?0.009 and p?=?0.04 respectively). Nevertheless, integrating the expression of CCAT1 and CCAT2 by the Random Forest classifier did not improve the predictive values of ColoMet19, the mRNA-based predictor for metastasis previously developed on the same series of tumours. The role of these two lncRNAs is probably mitigated via their oncotarget, c-Myc, which was not ranked high enough previously to be included in ColoMet19.
Project description:<h4>Background</h4>Long noncoding RNA single nucleotide polymorphisms (lncRNA-SNPs) PCAT1 rs710886, PRNCR1 rs1456315 and CCAT2 rs6983267 on 8q24 region present generalizability in the susceptibility to multiple cancers, however, the influence of rs710886, rs1456315 and rs6983267 on lung cancer has not been assessed. The aim of this study was to investigate associations between three lncRNA-SNPs and lung cancer.<h4>Methods</h4>A case-control study was performed on 438 patients with lung cancer and 456 healthy controls in the Han population from southern China. The collected samples were genotyped by the TaqMan genotyping, and the association with clinical characteristics, including age, gender, drinking status, smoking status, pathological types and clinical stages were analyzed. And the SNP function prediction was based on lncRNASNP2, RNAfold and GTEx.<h4>Results</h4>The rs1456315 T allele increased the risk of lung cancer [OR=1.95, 95% CI (1.58-2.43), <i>P</i>=0.003] compared to the rs1456315 C allele, and rs1456315 significantly increased the risk of lung cancer in the dominant model [OR=1.86, 95% CI (1.16-3.00), <i>P</i>=0.002]. The rs6983267 G allele, compared with the T allele, increased the risk of lung cancer [OR=1.29, 95% CI (1.07-1.57), <i>P</i>=0.007], and rs6983267 was identified as a risk factor for lung cancer [OR=1.28, 95% CI (1.06-1.55), <i>P</i>=0.003] in the additive model. Both rs1456315 and rs6983267 demonstrated significance after adjusting for the smoking status, drinking status and age. The structure prediction found rs6983267 and rs1456315 influence the secondary structure of its lncRNA. The results from lncRNASNP2 indicated that rs6983267 and rs1456315 change gain/loss target of miRNAs.<h4>Conclusion</h4><i>PRNCR1</i> rs1456315 and <i>CCAT2</i> rs6983267 on 8q24 region are significantly associated with lung cancer in the Han population of southern China and alter the potential biological function in bioinformatic analysis, and the results further extended generalism of the susceptibility of cancer-associated lncRNA-SNPs to lung cancer and underlying mechanism involved in lung cancer.
Project description:The worldwide incidence of hepatocellular carcinoma (HCC), the major histological type of primary liver cancer, is heterogeneous due to the variable prevalence of etiological factors, indicating a correlation of HCC risk with genetic variations among individuals. Among long non-coding RNAs (lncRNAs) located in the chromosome 8q24 loci and involved in the carcinogenesis are colon cancer associated transcript 2 (CCAT2) and cancer susceptibility candidate 8 (CASC8). In this study, the association of CCAT2 and CASC8 gene polymorphisms with the occurrence of HCC was explored between 397 HCC patients and 1195 controls. We found that carriers of rs6983267 GG in CCAT2 were more susceptible to HCC, with the odds ratio (OR) and adjusted odds ratio (AOR) being 1.532 (95% CI, 1.103-2.129; p = 0.011) and 1.627 (95% CI, 1.120-2.265; p = 0.033), respectively. Moreover, for patients stratified by age (under 65), gender (male only), or status of drinking (habitual drinkers), a protective effect of CASC8 rs3843549 on presenting high Child-Pugh scores, metastatic vascular invasion, or large-size tumors was observed in a dominant model. Collectively, our data reveal association of CCAT2 and CASC8 gene polymorphisms with the occurrence and progression of HCC.
Project description:Background:Colon cancer-associated transcript 2 (CCAT2) is a newly recognized lncRNA transcribed from the 8q24 genomic region. It functions as an oncogene in various types of cancers including breast cancer, in which it affects Wnt/?-catenin pathway. Previous studies have shown a putative interaction between this lncRNA and MYC proto-oncogene. Methods:In the current study, we evaluated the expression of CCAT2 in breast cancer tissues with regards to the expression of its target MYC. In addition, we assessed the relationship between CCAT2 and MYC expression levels in tumor tissues and the clinical prognostic characteristics of breast cancer patients. Results:MYC expression levels were significantly up-regulated in tumor tissues compared with adjacent non-cancerous tissues (ANCTs), while such analysis showed no statistically significant difference between these two tissue types in CCAT2 expression. Starkly increased CCAT2 gene expression levels were found in 12/48 (25%) of cancer tissue samples compared with their corresponding ANCTs. Furthermore, significant inverse correlations were found between CCAT2 expression and stage, as well as lymph node involvement. Besides, a significant inverse correlation was found between the relative MYC expression in tumor tissues compared with their corresponding ANCTs and disease stage. Conclusion:These results highlight the significance of MYC and CCAT2 expressions in the early stages of breast cancer development and suggest a potentially significant role for CCAT2 in a subset of breast cancer patients, which could be applied as a potential therapeutic target in these patients.
Project description:Retrospective series of primary breast cancer patients who received surgery between 1989 and 1992. Patients received adjuvant chemotherapy and/or adjuvant hormone therapy, or no adjuvant treatment. Tamoxifen was used as endocrine therapy for 5 years in ER+ BC patients. Patients who were <50 years of age, with lymph node positive tumors, or ER– and/or >3 cm in diameter, received adjuvant cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) for six cycles, in a thrice weekly intravenous regimen. Patients >50 years of age with ER–, lymph node–positive tumors also received CMF. Retrospective clinical study to identify breast cancer prognostic markers and associated pathways. 216 early primary breast cancers were considered who had complete 10-years follow-up, clinical and demographics information. mRNA profiling data.