Role In Other Cancer Types Research Articles

MiR-152-mediated MKK7 downregulation is attenuated by MYCNOS in ovarian adenocarcinoma.

MYCN opposite strand (MYCNOS) acts as an oncogenic long non-coding RNA in liver cancer. However, its role in other cancer types is unknown. The aim of the present study was to investigate the function of MYCNOS in ovarian adenocarcinoma (OA). MYCNOS expression in OA was determined using reverse transcription-quantitative PCR (RT-qPCR), and its prognostic value for OA was evaluated in a 5-year follow-up study. The predicted interaction between MYCNOS and microRNA (miR)-152 was confirmed using a dual luciferase reporter assay. The association between MYCNOS and miR-152 was also analyzed in overexpression experiments. The effects of MYCNOS and miR-152 on mitogen-activated protein kinase kinase 7 (MKK7) expression were explored using RT-qPCR and western blotting. Cell proliferation was analyzed using a Cell Counting Kit-8 assay. MYCNOS expression was found to be upregulated in OA and predicted poor survival. In addition, MYCNOS was predicted to interact with miR-152, and a dual luciferase assay confirmed this interaction. However, MYCNOS and miR-152 overexpression did not affect their mutual expression levels. MYCNOS overexpression upregulated MKK7, a target of miR-152. Cell proliferation increased following simultaneous MYCNOS and MKK7 overexpression, but was reduced following miR-152 overexpression. Moreover, MYCNOS overexpression attenuated the effects of miR-152 overexpression. In conclusion, MYCNOS may act by sponging miR-152 to upregulate MKK7 expression in OA, thereby promoting cell proliferation.

AUNIP Expression Is Correlated With Immune Infiltration and Is a Candidate Diagnostic and Prognostic Biomarker for Hepatocellular Carcinoma and Lung Adenocarcinoma.

AUNIP, a novel prognostic biomarker, has been shown to be associated with stromal and immune scores in oral squamous cell carcinoma (OSCC). Nonetheless, its role in other cancer types was unclear. In this study, AUNIP expression was increased in hepatocellular carcinoma (HCC) and lung adenocarcinoma (LUAD) according to data from The Cancer Genome Atlas (TCGA) database, Integrative Molecular Database of Hepatocellular Carcinoma (HCCDB), and Gene Expression Omnibus (GEO) database (GSE45436, GSE102079, GSE10072, GSE31210, and GSE43458). Further, according to copy number variation analysis, AUNIP up-regulation may be associated with copy number variation. Immunohistochemistry showed AUNIP expression was higher in HCC and LUAD compared with the normal tissues. Receiver operating characteristic (ROC) curve analysis demonstrated that AUNIP is a candidate diagnostic biomarker for HCC and LUAD. Next, TCGA, International Cancer Genome Consortium (ICGC), and GEO (GSE31210 and GSE50081) data showed that increased AUNIP expression clearly predicted poor overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI) in HCC and LUAD. Additionally, multivariate Cox regression analysis involving various clinical factors showed that AUNIP is an independent prognostic biomarker for HCC and LUAD. Next, the role of AUNIP in HCC and LUAD was explored via a co-expression analysis, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, and a gene set variation analysis (GSVA). HCC and LUAD exhibited almost identical enrichment results. More specifically, high AUNIP expression was associated with DNA replication, cell cycle, oocyte meiosis, homologous recombination, mismatch repair, the p53 signal transduction pathway, and progesterone-mediated oocyte maturation. Lastly, the Tumor Immune Estimation Resource (TIMER) tool was used to determine the correlations of AUNIP expression with tumor immune infiltration. AUNIP expression was positively correlated with the infiltration degree of B cells, CD4+ T cells, CD8+ T cells, neutrophils, macrophages, and dendritic cells in HCC. However, AUNIP expression was negatively correlated with the infiltration degree of B cells, CD4+ T cells, and macrophages in LUAD. In addition, AUNIP expression was correlated with immune infiltration in various other tumors. In conclusion, AUNIP, which is associated with tumor immune infiltration, is a candidate diagnostic and prognostic biomarker for HCC and LUAD.

Long noncoding RNA UCA1 enhances sensitivity to oncolytic vaccinia virus by sponging miR-18a/miR-182 and modulating the Cdc42/filopodia axis in colorectal cancer

The promising anti-tumor effects of oncolytic vaccinia virus (OVV) have been demonstrated. Further, we previously showed that long non-coding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) enhances OVV cell-to-cell spread via the activation of Cdc42 in ovarian cancer. However, its role in other cancer types and the molecular mechanism underlying its effects remain to be explored. In this study, we first demonstrated that UCA1 upregulates OVV cell-to-cell spread but not its binding, entry, and replication in colorectal cancer cells. Functional analysis indicated that Cdc42 activation and filopodia formation play an important role in this process. Moreover, expression analysis of various miRNAs suggested that UCA1 inhibits both miR-18a and miR-182, thereby promoting Cdc42 activation, which in turn, regulates OVV cell-to-cell spread. Furthermore, UCA1 was found to modulate tumor malignancy, drug resistance, and sensitivity to OVV via different miRNAs in colorectal cancer. These findings indicate that a three-marker panel, which includes UCA1 expression, Cdc42 activation, and filopodia formation, could potentially be used to predict the therapeutic effect of OVV in colorectal cancer.

Epstein-Barr Virus-Positive Cancers Show Altered B-Cell Clonality

Epstein-Barr virus (EBV) is convincingly associated with gastric cancer, nasopharyngeal carcinoma, and certain lymphomas, but its role in other cancer types remains controversial. To test the hypothesis that there are additional cancer types with high prevalence of EBV, we determined EBV viral expression in all the Cancer Genome Atlas Project (TCGA) mRNA sequencing (mRNA-seq) samples (n = 10,396) from 32 different tumor types. We found that EBV was present in gastric adenocarcinoma and lymphoma, as expected, and was also present in >5% of samples in 10 additional tumor types. For most samples, EBV transcript levels were low, which suggests that EBV was likely present due to infected infiltrating B cells. In order to determine if there was a difference in the B-cell populations, we assembled B-cell receptors for each sample and found B-cell receptor abundance (P ≤ 1.4 × 10-20) and diversity (P ≤ 8.3 × 10-27) were significantly higher in EBV-positive samples. Moreover, diversity was independent of B-cell abundance, suggesting that the presence of EBV was associated with an increased and altered B-cell population. IMPORTANCE Around 20% of human cancers are associated with viruses. Epstein-Barr virus (EBV) contributes to gastric cancer, nasopharyngeal carcinoma, and certain lymphomas, but its role in other cancer types remains controversial. We assessed the prevalence of EBV in RNA-seq from 32 tumor types in the Cancer Genome Atlas Project (TCGA) and found EBV to be present in >5% of samples in 12 tumor types. EBV infects epithelial cells and B cells and in B cells causes proliferation. We hypothesized that the low expression of EBV in most of the tumor types was due to infiltration of B cells into the tumor. The increase in B-cell abundance and diversity in subjects where EBV was detected in the tumors strengthens this hypothesis. Overall, we found that EBV was associated with an increased and altered immune response. This result is not evidence of causality, but a potential novel biomarker for tumor immune status.

Abstract 5743: Characterization of mitochondrial DNA mutations and tumor evolution in ulcerative colitis-associated colorectal cancer

Abstract The role of mitochondrial DNA (mtDNA) mutations in cancer is highly controversial. While specific mtDNA mutations have been associated with certain cancers, it has been recently reported that mtDNA mutations are negatively selected in most tumors. We aimed to clarify the role of mtDNA mutations in cancer progression by: 1) capitalizing on the multi-step sequence of tumorigenesis in ulcerative colitis (UC), a premalignant disease ideal for the study of tumor progression, and 2) employing a highly accurate, ultra-deep sequencing method to fully characterize the mtDNA mutational profile at different stages of tumor evolution. UC is an inflammatory bowel disease characterized by chronic colonic inflammation that increases the risk of colorectal cancer (CRC). UC CRC evolves through a stepwise process that involves the accumulation of molecular alterations in otherwise histologically normal epithelium, low-grade dysplasia (LGD), high-grade dysplasia (HGD), and cancer. Our lab has previously identified mitochondrial alterations as a facet of dysplastic progression in UC. Here we have worked to fully characterize the spectrum and frequency of mtDNA mutations in UC tumorigenesis by applying a novel, highly sensitive NGS technology, Duplex Sequencing (DS), that can accurately detect mutant allele frequencies (MAF) as low as 0.01%. For two patients that developed cancer, we analyzed 15-20 colon biopsies obtained at colectomy, representing all stages of tumorigenesis. The median duplex sequencing depth was 4,000x, which allowed unprecedented resolution to detect subclonal mutations (MAF 1-99%) and rare mutations (MAF<1%). Several subclonal mutations were present in all biopsies, but with variable MAF, thus enabling construction of phylogenetic trees via PHYLIP analysis. Rare mutations were abundant in all biopsies; on average one in every 10,000 nucleotides sequenced was mutated. Most rare mutations were G to A transitions, indicative of replicative errors, but G to T and C to A transversions, the oxidative damage mutational signature, were prevalent in some biopsies. We conclude, therefore, that most mtDNA mutations are caused by proliferation with a contribution by inflammatory processes, and that this may have greater implications for their role in other cancer types. Citation Format: Kathryn Terese Baker, Daniela Nachmanson, Scott R. Kennedy, Teresa A. Brentnall, Rosa Ana Risques. Characterization of mitochondrial DNA mutations and tumor evolution in ulcerative colitis-associated colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5743. doi:10.1158/1538-7445.AM2017-5743

Crk II silencing down-regulates IGF-IR and inhibits migration and invasion of prostate cancer cells

Crk (C10 regulator of kinase) adaptor proteins are highly expressed in many types of human cancers and often contribute to aggressive cancer phenotypes. Crk II, a member of CRK family, has been reported to regulate cell migration and metastasis in breast cancer cells. However, its role in other cancer types has not been reported. In this study, we investigated the molecular function of Crk II in prostate cancer (PCa) cells (CWR-22rv1) in vitro and using a mouse tumor model. Results showed that Crk II knockdown by shRNA-mediated silencing (Crk II-shRNA) in the PCa cells significantly inhibited both cancer cell migration and invasion in cell culture study. Crk II-shRNA cancer cells also significantly decreased colony formation in vitro, but had no significant reduction of tumor volume after 4 weeks of cancer cell xenografting in vivo when compared to the scramble control. Interestingly, Crk II-shRNA cancer cells showed a greatly reduced level of insulin-like growth factor 1 receptor (IGF-1R) and decreased signaling of the IGF-1R/PI3K/Akt axis upon IGF-1 ligand stimulation. A close interaction between Crk II and IGF-1R was demonstrated upon co-immunoprecipitation of IGF-1R with Crk II protein. Further, treatment of cells with either proteosomal degradation or protein synthesis inhibitor showed higher proportion of ubiquitin-associated IGF-1R and faster degradation of IGF-1R in Crk II-shRNA cells in comparison with that in the control cancer cells. Taken together, these data suggest that Crk II plays an important role in the regulation of IGF-1R protein stability and affects downstream of IGF-1R signaling pathways. Therefore, targeting Crk-II can block IGF-1R growth signaling and suppress cancer cell invasion and progression.

Peroxisome Proliferator-activated Receptor γ Agonists Induce Cell Cycle Arrest through Transcriptional Regulation of Krüppel-like Factor 4 (KLF4)

Peroxisome proliferator-activated receptor γ (PPARγ), a subgroup of ligand-activated nuclear receptors, plays critical roles in cell cycle regulation, differentiation, apoptosis, and invasion. PPARγ is involved in tumorigenesis and is a potent target for cancer therapy. PPARγ transactivation of KLF4 has been demonstrated in various studies; however, how PPARγ regulates KLF4 expression is not clear. In this study, we reveal that PPARγ regulates the expression of KLF4 by binding directly to the PPAR response element (PPRE) within the KLF4 promoter. The PPRE resides at -1657 to -1669 bp upstream of the KLF4 ATG codon, which is essential for the transactivation of troglitazone-induced KLF4 expression. Furthermore, we found that stable silencing of KLF4 obviously suppressed the G(1)/S arrest and anti-proliferation effects induced by PPARγ ligands. Taken together, our data indicate that up-regulation of KLF4 upon PPARγ activation is mediated through the PPRE in the KLF4 promoter, thus providing further insights into the PPARγ signal transduction pathway as well as a novel cancer therapeutic strategy.

MELD-sodium score and its prognostic value in malignancy-related ascites of pancreatic and gastric cancer

Malignant ascites is a manifestation of end-stage events in a variety of cancers. There is significant lack of possible survival predictors in patients with malignancy-related ascites. Since the Model for End-Stage Liver Disease (MELD)-Na score has been shown to be a feasible and independent prognostic predictor for both short- and long-term outcome in HCC patients, we decided to test its prognostic role in other cancer types with ascites. This is a retrospective study. The outpatient oncology clinic's records were screened for the period between 2004 and 2011. Eighty-two pancreatic and gastric cancer patients were enrolled into the study. The median age of patients was 59 (±12). Fifty-nine patients had gastric cancer and 23 had pancreatic cancer. Overall survival (OS) was 16.8 (IR, 1-98) months in gastric cancer and 16.3 (IR, 0.5-81) months in pancreatic cancer. There was no statistically significant difference between OS of gastric and pancreatic cancer. Progression-free survival (PFS) was statistically significantly longer in gastric cancer than pancreatic cancer with 16.5 (IR, 0.5-90) vs 6.5 (IR, 0.4-34) months (P = 0.04). Further analysis of data included stepwise multiple regression analysis with the dependent variable "overall survival." The model had two independent predictors and an R(2) of 82 % and a predicted R(2) of 81 %. Predictors for time to remission were PFS and MELD-Na. The regression equation for the model was: Overall survival =17.4- 0.522 MELD-Na + 0.902 PFS CONCLUSION: In this study we showed that progression-free survival and MELD-Na score are significantly related with overall survival. MELD-Na score can be one of the predictors of the survival and PFS in pancreatic and gastric cancer patients with ascites.

Epigenetic inactivation ofMCJ (DNAJD1) in malignant paediatric brain tumours

MCJ (DNAJD1) is a recently discovered member of the DNAJ protein family whose expression is controlled epigenetically by methylation of a CpG island located within the 5' transcribed region of its gene. Methylation-dependent transcriptional silencing of MCJ has been observed in ovarian cancers and associated with increased resistance to chemotherapeutic agents; however, its role in other cancer types has not been widely investigated. We examined the status of MCJ in intracranial primitive neuroectodermal tumours [PNETs, comprising cerebellar PNETs (medulloblastomas) and supratentorial PNETs (stPNETs)] and ependymomas, together representing the most common malignant brain tumours of childhood. Evidence of MCJ hypermethylation was found in all 3 tumour types [medulloblastomas, 3/9 (33%) cell lines, 2/28 (7%) primary tumours; stPNETs, 2/2 (100%) cell lines, 3/10 (30%) primary tumours; and ependymomas, 2/20 (10%) primary tumours] but not in nonneoplastic brain tissues (n = 11), indicating that MCJ methylation is a tumour-specific event. In methylated cases, the distribution of methylated CpG sites across the CpG island could be broadly divided into 2 patterns: (i) extensive methylation of the majority of CpG sites across the island or (ii) limited methylation of individual CpG sites concentrated towards the 5' end of the island. Extensive methylation patterns were associated with the methylation-dependent transcriptional silencing of MCJ in medulloblastoma and stPNET cell lines. Further investigations of the mechanism of MCJ inactivation revealed that its loss could occur either through biallelic epigenetic methylation or by methylation in association with genetic loss of its second allele. These data indicate that epigenetic inactivation of MCJ may play a role in the development of a range of paediatric brain tumour types, and its role in disease pathogenesis and chemotherapeutic resistance should now be investigated further.

Retinoblastoma Gene Product-Associated Proteins in Human Colon Cancer Cell Lines

The expression of cellular proteins that associate with the human retinoblastoma (RB1) gene protein was examined in three colorectal carcinoma cell lines (SW480, SW403, DiFi) by immunoprecipitation analysis, using the mouse monoclonal antibody (RB-MAb-1) directed against the RB1 gene product (RB). The potential of RB-MAb-1 to detect RB-associated proteins by immunoprecipitation analysis was confirmed using three control cell lines (WI-38, J82, T24) known to express RB and/or RB-associated proteins. In all colon cancer cell lines tested, multiple RB-associated protein (RAP) bands were found with molecular weights of 30-50 kDa. Because involvement of the RB1 gene in colorectal tumorigenesis appears to differ from its role in other cancer types (wherein RB1 is lost or inactivated), it will be important to characterize the role of RAPs in RB growth regulatory mechanisms of colonic epithelial cells.