PARP-1 may be involved in angiogenesis in epithelial ovarian cancer.
ABSTRACT: Poly (ADP-ribose) polymerase 1 (PARP-1) is involved in DNA repair and has been implicated in chemoresistance. The present study investigated whether PARP-1 promotes angiogenesis in ovarian cancer. PARP-1 and vascular endothelial growth factor A (VEGF-A) expression and CD34+ microvascular density (MVD) were assessed using immunohistochemistry in 60 human epithelial ovarian cancer specimens. PARP-1 was stably knocked-down in SKOV3 cells using a specific small interfering RNA (siRNA); angiogenic capacity was assessed using the human umbilical vein endothelial cell (HUVEC) tubule formation assay; and PARP-1 and VEGF-A expression were examined by reverse transcription-quantitative polymerase chain reaction, western blotting and ELISA. PARP-1 was found to be expressed in 73.3% (44/60) of the human epithelial ovarian cancer specimens and was significantly associated with VEGF-A, MVD, tumor size, histological grade and lymphatic metastasis (P<0.05). Compared with cells transfected with a negative control siRNA, knockdown of PARP-1 significantly suppressed the ability of SKOV3 cell-conditioned media to promote HUVEC tubule formation on Matrigel in vitro. Knockdown of PARP-1 in SKOV3 cells also significantly reduced VEGF-A mRNA and protein expression and secretion. In summary, PARP-1 is overexpressed and may enhance angiogenesis in epithelial ovarian cancer by upregulating VEGF-A.
Project description:CD24 is involved in tumor progression of various cancers, but the effects of CD24 on tumor angiogenesis in colorectal cancer are still unknown. We aimed to investigate the underlying mechanism and role of CD24 on colorectal cancer (CRC) angiogenesis. Our data showed that the microvessal density (MVD) was related to the expression of CD24 in primary and metastasis CRC. Silencing of CD24 could dramatically decrease human umbilical vein endothelial cell (HUVEC) migration, invasion and tubule formation, but trivially affected cell proliferation. We also mechanically showed that silencing CD24 could downregulate the expression of VEGF via inhibiting the phosphorylation and translocation of STAT3. Moreover, Hsp90 was identified as the down-interaction protein of CD24 with co-immunoprecipitation assay and systematic mass spectrometry. Immunofluorescence results showed Hsp90 partly co-localized with CD24 in CRC cell membrane and there was a positive correlation between CD24 and Hsp90 expression in CRC tissues. We gradually evidenced that Hsp90 modulated the stability and degradation of CD24 in a proteasome-depended manner, and transferred the signal transmission from CD24 to STAT3. 17-AAG, a specific Hsp90, could abrogate the CD24 induce- HUVEC migration, invasion and tubule formation in vitro and in vivo. Collectively, our results suggested that CD24 induced CRC angiogenesis in Hsp90-dependent manner and activated STAT3-mediated transcription of VEGF. We provided a new insight into the regulation mechanism of tumor angiogenesis by exploring the role of CD24 in angiogenesis.
Project description:<h4>Background</h4>Aldehyde dehydrogenase 1A1 (ALDH1A1), a member of aldehyde dehydrogenase family, is a marker of stemness in breast cancer. During tumor progression cancer stem cells (CSCs) have been reported to secrete angiogenic factors to orchestrate the formation of pathological angiogenesis. This vasculature can represent the source of self-renewal of CSCs and the route for further tumor spreading. The aim of the present study has been to assess whether ALDH1A1 controls the output of angiogenic factors in breast cancer cells and regulates tumor angiogenesis in a panel of in vitro and in vivo models.<h4>Methods</h4>Stemness status of breast cancer cells was evaluated by the ability to form turmorspheres in vitro. A transwell system was used to assess the angiogenic features of human umbilical vein endothelial cells (HUVEC) when co-cultured with breast cancer cells MCF-7 harboring different levels of ALDH1A1. Under these conditions, we survey endothelial proliferation, migration, tube formation and permeability. Moreover, in vivo, MCF-7 xenografts in immunodeficient mice allow to evaluate blood flow, expression of angiogenic factors and microvascular density (MVD).<h4>Results</h4>In MCF-7 we observed that ALDH1A1 activity conferred stemness property and its expression correlated with an activation of angiogenic factors. In particular we observed a significant upregulation of hypoxia inducible factor-1α (HIF-1α) and proangiogenic factors, such as vascular endothelial growth factor (VEGF). High levels of ALDH1A1, through the retinoic acid pathway, were significantly associated with VEGF-mediated angiogenesis in vitro. Co-culture of HUVEC with ALDH1A1 expressing tumor cells promoted endothelial proliferation, migration, tube formation and permeability. Conversely, downregulation of ALDH1A1 in MCF-7 resulted in reduction of proangiogenic factor release/expression and impaired HUVEC angiogenic functions. In vivo, when subcutaneously implanted in immunodeficient mice, ALDH1A1 overexpressing breast tumor cells displayed a higher expression of VEGF and MVD.<h4>Conclusion</h4>In breast tumors, ALDH1A1 expression primes a permissive microenvironment by promoting tumor angiogenesis via retinoic acid dependent mechanism. In conclusion, ALDH1A1 might be associated to progression and diffusion of breast cancer.
Project description:Adrenomedullin (ADM) is a multi-functional peptide related to many kinds of tumors. This study was aimed to investigate the role of ADM on angiogenesis in epithelial ovarian cancer (EOC) and its possible mechanism. The expressions of ADM, vascular endothelial growth factor (VEGF), hypoxia-inducible factor-1? (HIF-1?) and CD34 were examined by immunohistochemistry staining. The relationship among ADM, HIF-1?, VEGF and micro-vessel density (MVD) was assessed in 56 EOC tissues. CAOV3 cells were stably transfected with pcDNA-ADM (plasmid overexpressing ADM gene) or pRNA-shADM (small interfering RNA for ADM gene). Real-time PCR and western blot analysis were performed to detect the expressions of HIF-1? and VEGF. The MTT, transwell migration assay and in vitro tube formation analysis were used to evaluate the proliferation, migration, and tube formation ability of human umbilical vein endothelial cells (HUVECs) which were pretreated with ADM or ADM receptor antagonist ADM22-52. Our findings showed that ADM expression was positively correlated with the expressions of HIF-1?, VEGF or MVD in EOC. ADM upregulated expression of HIF-1? and VEGF in CAOV3 cells. ADM promoted HUVECs proliferation, migration and tube formation. In conclusion, ADM was an upstream molecule of HIF-1?/VEGF and it promoted angiogenesis through upregulating HIF-1?/VEGF in EOC.
Project description:The importance of tissue transglutaminase (TG2) in angiogenesis is unclear and contradictory. Here we show that inhibition of extracellular TG2 protein crosslinking or downregulation of TG2 expression leads to inhibition of angiogenesis in cell culture, the aorta ring assay and in vivo models. In a human umbilical vein endothelial cell (HUVEC) co-culture model, inhibition of extracellular TG2 activity can halt the progression of angiogenesis, even when introduced after tubule formation has commenced and after addition of excess vascular endothelial growth factor (VEGF). In both cases, this leads to a significant reduction in tubule branching. Knockdown of TG2 by short hairpin (shRNA) results in inhibition of HUVEC migration and tubule formation, which can be restored by add back of wt TG2, but not by the transamidation-defective but GTP-binding mutant W241A. TG2 inhibition results in inhibition of fibronectin deposition in HUVEC monocultures with a parallel reduction in matrix-bound VEGFA, leading to a reduction in phosphorylated VEGF receptor 2 (VEGFR2) at Tyr¹²¹? and its downstream effectors Akt and ERK1/2, and importantly its association with ?1 integrin. We propose a mechanism for the involvement of matrix-bound VEGFA in angiogenesis that is dependent on extracellular TG2-related activity.
Project description:The infiltration of tumor-associated macrophages (TAMs) is associated with extensive angiogenesis, which contributes to a poor prognosis in breast cancer. However, anti-angiogenic therapy with VEGF-specific monotherapy has been unsuccessful in treating breast cancer, and the molecular mechanisms associated with chemoresistance remain unclear. Here, we investigated whether CCL18, a chemokine produced by TAMs, can stimulate angiogenesis in breast cancer, as well as the underlying mechanisms. Double immunohistochemical staining for CCL18 and CD34/CD31/vWF was performed in 80 breast cancer samples to study the correlation between CCL18+ TAMs and microvascular density (MVD). Cocultures of TAMs with human umbilical vein endothelial cells (HUVECs) were used to model the inflammatory microenvironment, and CCL18-induced angiogenesis was evaluated both in vitro and in vivo. We demonstrated that CCL18+ TAM infiltration positively associated with MVD in breast cancer samples, which was correlated with tumor metastasis and poor prognosis. We confirmed, both in vitro and in vivo, that CCL18 and VEGF synergistically promoted endothelial cell migration and angiogenesis. Conversely, blocking CCL18 or VEGF with neutralizing antibodies synergistically inhibited the promigratory effects of TAMs. Silencing PITPNM3, a putative CCL18 receptor, on the surface of HUVECs abrogated CCL18-mediated promigration and the enhancement of HUVEC tube formation, independently of VEGFR signaling. Moreover, CCL18 exposure induced the endothelial-mesenchymal transformation and activated ERK and Akt/GSK-3?/Snail signaling in HUVECs, thereby contributing to its pro-angiogenic effects. In conclusion, our findings suggest that CCL18 released from TAMs promotes angiogenesis and tumor progression in breast cancer; thus, CCL18 may serve as a novel target for anti-angiogenic therapies.
Project description:Ovarian cancer is one of the most lethal gynecologic malignancies. It has been shown that PARP inhibitors can selectively target BRCA-mutated ovarian cancer and exert some effects on ovarian cancer without BRCA mutations. However, the mechanism is still unclear. In this study, wild-type BRCA ovarian cancer cells (A2780 and SKOV3) were used. Our results showed that using a PARP inhibitor (olaparib or AG14361) alone significantly inhibited the proliferation of A2780 cells but negligibly inhibited the proliferation of SKOV3 cells. We used RNA sequencing to explore differentially expressed genes and found that PARP inhibitors increased LDH-A in SKOV3 cells, which was confirmed by RT-PCR. Oxamate (a specific inhibitor of LDH-A) was used to investigate whether LDH-A inhibition enhances the suppressive effects of PARP inhibitors on ovarian cancer without BRCA mutations. CCK-8 assays, scratch assays and Transwell assays were used to determine cell proliferation, cell migration ability and invasion ability, respectively. Both olaparib and AG14361 significantly inhibited the proliferation/invasion ability of A2780 cells but not SKOV3 cells. Inhibition of LDH-A can remarkably promote the inhibitory effects of PARP inhibitors on both A2780 and SKOV3 cells. Thus, high expression level of LDH-A influenced the suppressive effects of PARP inhibitors on ovarian cancer with wild-type BRCA, and LDH-A inhibition notably enhanced this effect.
Project description:Nerve Growth Factor (NGF) and its high-affinity receptor tropomyosin receptor kinase A (TRKA) increase their expression during the progression of epithelial ovarian cancer (EOC), promoting cell proliferation and angiogenesis through several oncogenic proteins, such as c-MYC and vascular endothelial growth factor (VEGF). The expression of these proteins is controlled by microRNAs (miRs), such as miR-145, whose dysregulation has been related to cancer. The aims of this work were to evaluate in EOC cells whether NGF/TRKA decreases miR-145 levels, and the effect of miR-145 upregulation. The levels of miR-145-5p were assessed by qPCR in ovarian biopsies and ovarian cell lines (human ovarian surface epithelial cells (HOSE), A2780 and SKOV3) stimulated with NGF. Overexpression of miR-145 in ovarian cells was used to evaluate cell proliferation, migration, invasion, c-MYC and VEGF protein levels, as well as tumor formation and metastasis in vivo. In EOC samples, miR-145-5p levels were lower than in epithelial ovarian tumors. Overexpression of miR-145 decreased cell proliferation, migration and invasion of EOC cells, changes that were concomitant with the decrease in c-MYC and VEGF protein levels. We observed decreased tumor formation and suppressed metastasis behavior in mice injected with EOC cells that overexpressed miR-145. As expected, ovarian cell lines stimulated with NGF diminished miR-145-5p transcription and abundance. These results suggest that the tumoral effects of NGF/TRKA depend on the regulation of miR-145-5p levels in EOC cells, and that its upregulation could be used as a possible therapeutic strategy for EOC.
Project description:<h4>Background</h4>The molecular mechanisms responsible for angiogenesis and abnormal expression of angiogenic factors in gastric cancer, including vascular endothelial growth factor (VEGF), remain unclear. The histone demethylase retinoblastoma binding protein 2 (RBP2) is involved in gastric tumorgenesis by inhibiting the expression of cyclin-dependent kinase inhibitors (CDKIs).<h4>Methods</h4>The expression of RBP2, VEGF, CD31, CD34 and Ki67 was assessed in 30 human gastric cancer samples and normal control samples. We used quantitative RT-PCR, western blot analysis, ELISA, tube-formation assay and colony-formation assay to characterize the change in VEGF expression and associated biological activities induced by RBP2 silencing or overexpression. Luciferase assay and ChIP were used to explore the direct regulation of RBP2 on the promoter activity of VEGF. Nude mice and RBP2-targeted mutant mice were used to detect the role of RBP2 in VEGF expression and angiogenesis in vivo.<h4>Results</h4>RBP2 and VEGF were both overexpressed in human gastric cancer tissue, with greater microvessel density (MVD) and cell proliferation as compared with normal tissue. In gastric epithelial cell lines, RBP2 overexpression significantly promoted the expression of VEGF and the growth and angiogenesis of the cells, while RBP2 knockdown had the reverse effect. RBP2 directly bound to the promoter of VEGF to regulate its expression by histone H3K4 demethylation. The subcutis of nude mice transfected with BGC-823 cells with RBP2 knockdown showed reduced VEGF expression and MVD, with reduced carcinogenesis and cell proliferation. In addition, the gastric epithelia of RBP2 mutant mice with increased H3K4 trimethylation showed reduced VEGF expression and MVD.<h4>Conclusions</h4>The promotion of gastric tumorigenesis by RBP2 was significantly associated with transactivation of VEGF expression and elevated angiogenesis. Overexpression of RBP2 and activation of VEGF might play important roles in human gastric cancer development and progression.
Project description:Angiogenesis plays a pivotal role in normal ovarian physiology as well as in the progression of ovarian cancer through ascites formation and metastatic spread. Bevacizumab (Avastin(®), Genentech; South San Francisco, CA, USA), a humanized anti-vascular endothelial growth factor (VEGF) monoclonal antibody, is the most widely studied anti-angiogenesis agent both across tumor types and specifically in epithelial ovarian cancer. In 2005, single-agent bevacizumab at 15 mg/kg (IV) every 3 weeks was first reported to be active in a case of recurrent high-grade serous ovarian cancer after failing 11th line cytotoxic treatment. Since then, many case series, phase II and phase III trials have confirmed these results leading to regulatory approval in most countries including the US Food and Drug Administration in 2014. Guidelines now give clear recommendations as to when and how bevacizumab should be integrated into the ovarian cancer treatment paradigm. Other anti-VEGF agents such as the VEGF receptor (VEGFR) tyrosine kinase inhibitors have not shown increased activity or reduced toxicity relative to bevacizumab. However, anti-angiogenics other than anti-VEGF/VEGFR agents such as those targeting Angiopoietin-1 and -2 are in development as well as novel combinations with vascular disrupting agents (VDAs), PARP inhibitors and immune checkpoint inhibitors. Clearly, the benefits of anti-angiogenic agents such as bevacizumab must be carefully weighed against the cost and associated toxicities. Although almost all patients with ovarian cancer will receive an anti-angiogenic compound, cures are not increased. Predictive biomarkers are an urgent unmet need.
Project description:<h4>Background</h4>High-grade serous ovarian cancer (HGSOC) intratumoural vasculature evolution remains unknown. The study investigated changes in tumour microvessel density (MVD) in a large cohort of paired primary and recurrent HGSOC tissue samples and its impact on patients' clinico-pathological outcome.<h4>Methods</h4>A total of 222 primary (pOC) and recurrent (rOC) intra-patient paired HGSOC were assessed for immunohistochemical expression of angiogenesis-associated biomarkers (CD31, to evaluate MVD, and VEGF-A). Expression profiles were compared between pOCs and rOCs and correlated with patients' data.<h4>Results</h4>High intratumoural MVD and VEGF-A expression were observed in 75.7% (84/111) and 20.7% (23/111) pOCs, respectively. MVD<sup>high</sup> and VEGF<sup>(+)</sup> samples were detected in 51.4% (57/111) and 20.7% (23/111) rOCs, respectively. MVD<sup>high</sup>/VEGF<sup>(+)</sup> co-expression was found in 19.8% (22/111) and 8.1% (9/111) of pOCs and rOCs, respectively (p = 0.02). Pairwise analysis showed no significant change in MVD (p = 0.935) and VEGF-A (p = 0.121) levels from pOCs to rOCs. MVD<sup>high</sup> pOCs were associated with higher CD3<sup>(+)</sup> (p = 0.029) and CD8<sup>(+)</sup> (p = 0.013) intratumoural effector TILs, while VEGF<sup>(+)</sup> samples were most frequently encountered among BRCA-mutated tumours (p = 0.019). Multivariate analysis showed VEGF and MVD were not independent prognostic factors for OS.<h4>Conclusions</h4>HGSOC intratumoural vasculature did not undergo significant changes during disease progression. High concentration of CD31<sup>(+)</sup> vessels seems to promote recruitment of effector TILs. The study also provides preliminary evidence of the correlation between VEGF-positivity and BRCA status.