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Functional analysis of miR-34c as a putative tumor suppressor in high-grade serous ovarian cancer.

ABSTRACT: Altered microRNA expression patterns are implicated in the formation of many human diseases, including ovarian cancer. Our laboratory previously created Dicer(fl/fl)/Pten(fl/fl)/Amhr2(cre/+) mice, which developed high-grade serous carcinomas originating from mouse fallopian tubes, while neither Dicer(fl/fl)/Amhr2(cre/+) nor Pten(fl/fl)/Amhr2(cre/+) mice developed tumors. To explore miRNAs involved in the tumorigenesis in the double-knockout (DKO) mice, tumor cell lines were established from mouse primary tumors, and the most abundant miRNAs present in mouse normal fallopian tubes, let-7b and miR-34c, were expressed in these cell lines. We found that miR-34c had a more dramatic effect on inhibiting tumor cell viability than let-7b. The action of miR-34c induced tumor cell cycle arrest in G1 phase and apoptosis, and was accompanied with the regulation of key genes involved in cell proliferation and cell cycle G1/S transition. miR-34c suppressed the expression of Ezh2 and Mybl2, which may transcriptionally and functionally activate Cdkn1c. Furthermore, miR-34c levels are extremely low in human serous adenocarcinomas compared with human normal fallopian tubes. Expression of miR-34c in human ovarian cancer cells phenocopied its effects in DKO mouse tumor cells. However, miR-34b/c(-/-)/Pten(fl/fl)/Amhr2(cre/+) mice failed to develop high-grade serous carcinomas, implicating a combination of miRNAs in the tumorigenesis process. Thus, while miR-34c is a putative tumor suppressor in high-grade serous ovarian carcinoma with potential therapeutic advantages, screening of additional miRNAs for their effects alone and in combination with miR-34c is highly warranted to uncover miRNAs that synergize with miR-34c against cancer.

SUBMITTER: Yu Z

PROVIDER: S-EPMC6366460 | biostudies-literature | 2014 Nov

REPOSITORIES: biostudies-literature

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Functional analysis of miR-34c as a putative tumor suppressor in high-grade serous ovarian cancer.

Yu Zhifeng Z Kim Jaeyeon J He Lin L Creighton Chad J CJ Gunaratne Preethi H PH Hawkins Shannon M SM Matzuk Martin M MM

Biology of reproduction 20141001 5

Altered microRNA expression patterns are implicated in the formation of many human diseases, including ovarian cancer. Our laboratory previously created Dicer(fl/fl)/Pten(fl/fl)/Amhr2(cre/+) mice, which developed high-grade serous carcinomas originating from mouse fallopian tubes, while neither Dicer(fl/fl)/Amhr2(cre/+) nor Pten(fl/fl)/Amhr2(cre/+) mice developed tumors. To explore miRNAs involved in the tumorigenesis in the double-knockout (DKO) mice, tumor cell lines were established from mous ...[more]

PMID: 25273528

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Project description:ImportanceDespite similar histologic appearance among high-grade serous ovarian cancers (HGSOCs), clinical observations suggest vast differences in gross appearance. There is currently no systematic framework by which to classify HGSOCs according to their gross morphologic characteristics.ObjectiveTo develop and characterize a gross morphologic classification system for HGSOC.Design, setting, and participantsThis cohort study included patients with suspected advanced-stage ovarian cancer who presented between April 1, 2013, and August 5, 2016, to the University of Texas MD Anderson Cancer Center, a large referral center. Patients underwent laparoscopic assessment of disease burden before treatment and received a histopathologic diagnosis of HGSOC. Researchers assigning morphologic subtype and performing molecular analyses were blinded to clinical outcomes. Data analysis was performed between April 2020 and November 2021.ExposuresGross tumor morphologic characteristics.Main outcomes and measuresClinical outcomes and multiomic profiles of representative tumor samples of type I or type II morphologic subtypes were compared.ResultsOf 112 women (mean [SD] age 62.7 [9.7] years) included in the study, most patients (84% [94]) exhibited a predominant morphologic subtype and many (63% [71]) had a uniform morphologic subtype at all involved sites. Compared with those with uniform type I morphologic subtype, patients with uniform type II morphologic subtype were more likely to have a favorable Fagotti score (83% [19 of 23] vs 46% [22 of 48]; P = .004) and thus to be triaged to primary tumor reductive surgery. Similarly, patients with uniform type II morphologic subtype also had significantly higher mean (SD) estimated blood loss (639 [559; 95% CI, 391-887] mL vs 415 [527; 95% CI, 253-577] mL; P = .006) and longer mean (SD) operative time (408 [130; 95% CI, 350-466] minutes vs 333 [113; 95% CI, 298-367] minutes; P = .03) during tumor reductive surgery. Type I tumors had enrichment of epithelial-mesenchymal transition (false discovery rate [FDR] q-value, 3.10 × 10-24), hypoxia (FDR q-value, 1.52 × 10-5), and angiogenesis pathways (FDR q-value, 2.11 × 10-2), whereas type II tumors had enrichment of pathways related to MYC signaling (FDR q-value, 2.04 × 10-9) and cell cycle progression (FDR q-value, 1.10 × 10-5) by integrated proteomic and transcriptomic analysis. Abundances of metabolites and lipids also differed between the 2 morphologic subtypes.Conclusions and relevanceThis study identified 2 novel, gross morphologic subtypes of HGSOC, each with unique clinical features and molecular signatures. The findings may have implications for triaging patients to surgery or chemotherapy, identifying outcomes, and developing tailored therapeutic strategies.

Project description:BackgroundHigh grade serous ovarian cancer is characterised by high initial response to chemotherapy but poor outcome in the long term due to acquired resistance. One of the main genetic features of this disease is TP53 mutation. The majority of TP53 mutated tumors harbor missense mutations in this gene, correlated with p53 accumulation. TP53 null tumors constitute a specific subgroup characterised by nonsense, frameshift or splice-site mutations associated to complete absence of p53 expression. Different studies show that this kind of tumors may have a worse prognosis than other TP53 mutated HGSC.MethodsIn this study, we sought to characterise the intra-tumor heterogeneity of a TP53 null HGSC consisting of six primary tumor samples, two intra-pelvic and four extra-pelvic recurrences using exome sequencing and comparative genome hybridisation.ResultsSignificant heterogeneity was found among the different tumor samples, both at the mutational and copy number levels. Exome sequencing identified 102 variants, of which only 42 were common to all three samples; whereas 7 of the 18 copy number changes found by CGH analysis were presented in all samples. Sanger validation of 20 variants found by exome sequencing in additional regions of the primary tumor and the recurrence allowed us to establish a sequence of the tumor clonal evolution, identifying those populations that most likely gave rise to recurrences and genes potentially involved in this process, like GPNMB and TFDP1. Using functional annotation and network analysis, we identified those biological functions most significantly altered in this tumor. Remarkably, unexpected functions such as microtubule-based movement and lipid metabolism emerged as important for tumor development and progression, suggesting its potential interest as therapeutic targets.ConclusionsAltogether, our results shed light on the clonal evolution of the distinct tumor regions identifying the most aggressive subpopulations and at least some of the genes that may be implicated in its progression and recurrence, and highlights the importance of considering intra-tumor heterogeneity when carrying out genetic and genomic studies, especially when these are aimed to diagnostic procedures or to uncover possible therapeutic strategies.

Dataset Information

Functional analysis of miR-34c as a putative tumor suppressor in high-grade serous ovarian cancer.

Publications

Functional analysis of miR-34c as a putative tumor suppressor in high-grade serous ovarian cancer.

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