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VEGFA activates an epigenetic pathway upregulating ovarian cancer-initiating cells.

ABSTRACT: The angiogenic factor, VEGFA, is a therapeutic target in ovarian cancer (OVCA). VEGFA can also stimulate stem-like cells in certain cancers, but mechanisms thereof are poorly understood. Here, we show that VEGFA mediates stem cell actions in primary human OVCA culture and OVCA lines via VEGFR2-dependent Src activation to upregulate Bmi1, tumor spheres, and ALDH1 activity. The VEGFA-mediated increase in spheres was abrogated by Src inhibition or SRC knockdown. VEGFA stimulated sphere formation only in the ALDH1⁺ subpopulation and increased OVCA-initiating cells and tumor formation in vivo through Bmi1. In contrast to its action in hemopoietic malignancies, DNA methyl transferase 3A (DNMT3A) appears to play a pro-oncogenic role in ovarian cancer. VEGFA-driven Src increased DNMT3A leading to miR-128-2 methylation and upregulation of Bmi1 to increase stem-like cells. SRC knockdown was rescued by antagomir to miR-128. DNMT3A knockdown prevented VEGFA-driven miR-128-2 loss, and the increase in Bmi1 and tumor spheres. Analysis of over 1,300 primary human OVCAs revealed an aggressive subset in which high VEGFA is associated with miR-128-2 loss. Thus, VEGFA stimulates OVCA stem-like cells through Src-DNMT3A-driven miR-128-2 methylation and Bmi1 upregulation.

SUBMITTER: Jang K

PROVIDER: S-EPMC5331266 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature

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VEGFA activates an epigenetic pathway upregulating ovarian cancer-initiating cells.

Jang Kibeom K Kim Minsoon M Gilbert Candace A CA Simpkins Fiona F Ince Tan A TA Slingerland Joyce M JM

EMBO molecular medicine 20170301 3

The angiogenic factor, VEGFA, is a therapeutic target in ovarian cancer (OVCA). VEGFA can also stimulate stem-like cells in certain cancers, but mechanisms thereof are poorly understood. Here, we show that VEGFA mediates stem cell actions in primary human OVCA culture and OVCA lines via VEGFR2-dependent Src activation to upregulate Bmi1, tumor spheres, and ALDH1 activity. The VEGFA-mediated increase in spheres was abrogated by Src inhibition or <i>SRC</i> knockdown. VEGFA stimulated sphere forma ...[more]

PMID: 28179359

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Project description:BackgroundOvarian cancer (OC) is the most lethal gynecological cancer due to the recurrence of drug-resistance. Cancer initiating cells (CICs) are proposed to be responsible for the aggressiveness of OC. The rarity and difficulty of in vitro long-term cultivation of CICs challenge the development of CIC-targeting therapeutics. Reprogramming cancer cells into induced cancer initiating cell (iCICs) could be an approach to solve these. Several inducible CICs have been acquired by activating the expression of stemness genes in different cancer cells. However, few reports have demonstrated the feasibility in OC.MethodsPatients with primary OC receiving surgery were enrolled. Tumor tissue were collected, and OCT4, SOX2, and NANOG expressions were assessed by immunohistochemistry (IHC) staining to investigate the association of stemness markers with overall survival (OS). An high-grade serous ovarian cancer (HGSOC) cell line, OVCAR-3 was reprogrammed by transducing Yamanaka four factors OCT4, SOX2, KLF4 and MYC (OSKM) to establish an iOCIC model, iOVCAR-3-OSKM. CIC characteristics of iOVCAR-3-OSKM were evaluated by RT-PCR, sphere formation assay and animal experiments. Drug-resistance and migration ability were accessed by dye-efflux activity assay, MTT assay and migration assay. Gene profile was presented through RNA-sequencing. Lineage differentiation ability and organoid culture were determined by in vitro differentiation assays.ResultsIn OC patients, the co-expression of multiple stem-related transcription factors (OCT4, SOX2, and NANOG) was associated with worse OS. iOVCAR-3-OSKM cells generated by reprogramming successfully exhibited stemness characteristics with strong sphere-forming and tumorigenesis ability. iOVCAR-3-OSKM cells also showed malignant potential with higher drug resistance to chemodrug, Paclitaxel (PTX) and migration ability. iOVCAR-3-OSKM was maintainable and expandable on feeder-dependent culture condition, it also preserved ovarian lineage differentiation abilities, which could well differentiate into OC cells with CK-7 and CA125 expressions and develop into an organoid mimic poor prognostic OC histological feature.ConclusionsThe establishment of iOVCAR-3-OSKM not only allows us to fill the gap in the information on induced CICs in OC but also provides a potential strategy to develop personalized CICs and organoid models for treating OC in the near future.

Project description:PurposeAngiogenesis actively contributes to tumor growth and metastasis. MACC1 was reported to be associated with tumor progression. In the present study, we aimed to investigate the expression and role of MACC1 in cholangiocarcinoma (CCA) and its correlation with angiogenesis.Patients and methodsWe investigated the expression and correlation of MACC1 and VEGFA in The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets and in 7 paired frozen CCA and matched paracarcinoma tissues. Immunohistochemistry (IHC) was used to examine MACC1 and VEGFA expression as well as microvessel density (MVD) in 122 paraffin-embedded CCA samples. Western blotting, real-time qPCR and ELISA were performed to investigate the effect of MACC1 knockdown on VEGFA expression and secretion in CCA cells. Subsequently, we collected conditioned medium from cells with MACC1 knockdown and used it in angiogenesis assays.ResultsThe expression levels of both MACC1 and VEGFA were significantly upregulated in the TCGA and GEO datasets and in the 7 paired frozen CCA tissues compared to the matched paracarcinoma tissues, and MACC1 was significantly correlated with VEGFA. IHC showed that high expression of MACC1 and VEGFA was significantly correlated with lymph node metastasis (P<0.05 and P<0.01) and worse survival (P<0.01, P<0.05) in patients with CCA. We further verified that MACC1 was significantly correlated with VEGFA (P<0.01) and MVD (P<0.01) in clinical samples. Western blotting, real-time qPCR and ELISA results showed that MACC1 knockdown in CCA cells significantly decreased the protein and mRNA expression of VEGFA and reduced the VEGFA concentration in conditioned medium. Moreover, angiogenesis assays showed that conditioned medium from CCA cells with MACC1 knockdown decreased the number of tubes formed.ConclusionOur results indicate that MACC1 and VEGFA expression are upregulated in CCA. Moreover, MACC1 is an independent predictor of overall survival and facilitates angiogenesis in CCA by upregulating of VEGFA.

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VEGFA activates an epigenetic pathway upregulating ovarian cancer-initiating cells.

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VEGFA activates an epigenetic pathway upregulating ovarian cancer-initiating cells.

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