Glypican-3 reexpression regulates apoptosis in murine adenocarcinoma mammary cells modulating PI3K/Akt and p38MAPK signaling pathways (original) (raw)
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Breast Cancer Research and Treatment, 2009
Glypican-3 (GPC3) is a proteoglycan involved in migration, proliferation and cell survival modulation in several tissues. There are many reports demonstrating a downregulation of GPC3 expression in some human tumors, including mesothelioma, ovarian and breast cancer. Previously, we determined that GPC3 reexpression in the murine mammary adenocarcinoma LM3 cells induced an impairment of their in vivo invasive and metastatic capacities together with a higher susceptibility to in vitro apoptosis. Currently, the signaling mechanism of GPC3 is not clear. First, it was speculated that GPC3 regulates the insulin-like growth factor (IGF) signaling system. This hypothesis, however, has been strongly challenged. Recently, several reports indicated that at least in some cell types GPC3 serves as a selective regulator of Wnt signaling. Here we provide new data demonstrating that GPC3 regulates Wnt pathway in the metastatic adenocarcinoma mammary LM3 cell line. We found that GPC3 is able to inhibit canonical Wnt signals involved in cell proliferation and survival, as well as it is able to activate non canonical pathway, which directs cell morphology and migration. This is the first report indicating that breast tumor cell malignant properties can be reverted, at least in part, by GPC3 modulation of Wnt signaling. Our results are consistent with the potential role of GPC3 as a metastasis suppressor.
Inhibition of Invasion and Metastasis by Glypican-3 in a Syngeneic Breast Cancer Model
Breast Cancer Research and Treatment, 2003
Glypican-3 (GPC3), a proteoglycan bound to the cell membrane through a GPI anchor, is widely expressed in the embryo but down regulated in most adult tissues, with some exceptions as mammary cells. GPC3 is involved in the regulation of cell proliferation and survival in specific cell types. LM3, a murine mammary tumor cell line unable to express GPC3, was stably transfected with the rat GPC3 gene to analyze its role in tumor progression. Upon injection into syngeneic BALB/c mice LM3-GPC3 clones showed less local invasiveness and developed fewer spontaneous and experimental lung metastasis than controls. GPC3-expressing cells were more sensitive to apoptosis induced by serum depletion, exhibited a delay in the first steps of spreading and were less motile than controls. On the other hand, LM3-GPC3 cells were significantly more adherent to FN than control ones. We observed that GPC3 transfectants presented a higher expression of E-cadherin and β-catenin, molecules whose down regulation has been associated with tumor progression. Exogenous TGF-β increased MMP-9 activity in both control and GPC3-expressing cells, but did not modulate MMP-2. Contrarily, GPC3 expression prevented the increase of MMP-2 activity induced by IGF-II. Our results suggest that GPC3 has a protective role against mammary cancer progression.
Expression of Glypican-3 (GPC3) in Malignant and Non-malignant Human Breast Tissues
The Open Cancer Journal, 2015
Specific reports have linked GPC3 with cancer. Its usefulness as a marker has been proved for hepatocarcinoma, melanoma and ovary carcinoma. However, there are no studies analyzing GPC3 usefulness as a biomarker in mammary tumors. The aim of this work was to analyze GPC3 expression in breast tissues and to determine whether it might be useful as a biomarker in breast cancer patients. Expression level of GPC3 mRNA in Brazilian and Argentine human breast tumor (n=121) and peritumoral "normal" tissue (n=77) samples was analyzed using qRT-PCR. GPC3 protein expression was analyzed from 69 breast cancer and 10 peritumoral samples using IHC. Statistical analyses were done to evaluate the clinical-pathological significance of GPC3 expression. We found that Brazilian and Argentine populations are statistically different regarding GPC3 mRNA expression. In Argentine patients a lower GPC3 mRNA expression was found in tumors as compared to peritumoral tissues. No association was found between GPC3 mRNA and protein expression and the clinical-pathological parameters. The Kaplan-Meier curves suggested that elevated levels of GPC3 mRNA are associated with relapse. Our results indicate differential expression of GPC3 in mammary tumors in comparasion to normal breast tissues. They also suggest the potential role of GPC3 as a biomarker and the importance of deepening the study.
Glypican-3 induces a mesenchymal to epithelial transition in human breast cancer cells
Oncotarget, 2014
Breast cancer is the disease with the highest impact on global health, being metastasis the main cause of death. To metastasize, carcinoma cells must reactivate a latent program called epithelial-mesenchymal transition (EMT), through which epithelial cancer cells acquire mesenchymal-like traits. Glypican-3 (GPC3), a proteoglycan involved in the regulation of proliferation and survival, has been associated with cancer. In this study we observed that the expression of GPC3 is opposite to the invasive/metastatic ability of Hs578T, MDA-MB231, ZR-75-1 and MCF-7 human breast cancer cell lines. GPC3 silencing activated growth, cell death resistance, migration, and invasive/metastatic capacity of MCF-7 cancer cells, while GPC3 overexpression inhibited these properties in MDA-MB231 tumor cell line. Moreover, silencing of GPC3 deepened the MCF-7 breast cancer cells mesenchymal characteristics, decreasing the expression of the epithelial marker E-Cadherin. On the other side, GPC3 overexpression induced the mesenchymal-epithelial transition (MET) of MDA-MB231 breast cancer cells, which re-expressed E-Cadherin and reduced the expression of vimentin and N-Cadherin. While GPC3 inhibited the canonical Wnt/β-Catenin pathway in the breast cancer cells, this inhibition did not have effect on E-Cadherin expression. We demonstrated that the transcriptional repressor of E-Cadherin-ZEB1-is upregulated in GPC3 silenced MCF-7 cells, while it is downregulated when GPC3 was overexpressed in MDA-MB231 cells. We presented experimental evidences showing that GPC3 induces the E-Cadherin re-expression in MDA-MB231 cells through the downregulation of ZEB1. Our data indicate that GPC3 is an important regulator of EMT in breast cancer, and a potential target for procedures against breast cancer metastasis.
Glypican-4 (GPC-4) is a heparan sulphate glycoprotein, associated with cell membrane via a Glycosyl phosphatidyl (GPI)-anchor. It is involved in cell migration, cell growth, differentiation and morpho-genesis as well as chemoresistance and cancer stem cell maintenance in pancreatic cancer. However, its role in breast cancer remains unclear. To elucidate the role of GPC-4 in breast cancer, we analyzed GPC-4 expression in breast cancer patients and breast cancer cell lines. Our results demonstrated that GPC-4 expression was downregulated in metastatic tumors as compared to non-metastatic tumors. Further, GPC4's downregulation was confirmed in breast cancer metastatic cells (MDA-MBA-231 and MDA-MB-LM2) compared to non-metastatic cells (T47-D and MCF-7) with quantitative PCR and western blot. Knock-down of GPC-4 in non-metastatic cells significantly increased cell-migration and invasion. Similarly , over-expressing GPC-4 in metastatic cells decreased cell-migration/invasion and cell proliferation. Additionally, GPC-4 overexpression decreased in-vivo tumorigenicity in nude mice. Therefore, this research for the first time, has established the role of glypican-4 as a tumor-suppressor in breast cancer by decreasing migration and proliferation, revealing it as a possible therapy for breast cancer.
Glypican-3 promotes the growth of hepatocellular carcinoma by stimulating canonical Wnt signaling
Cancer research, 2005
Glypican-3 (GPC3) is a heparan sulfate proteoglycan that is bound to the cell membrane by a glycosyl-phosphatidylinositol anchor. GPC3 is expressed by most hepatocellular carcinomas but not by normal hepatocytes and benign liver lesions. We report here that GPC3 stimulates the in vitro and in vivo growth of hepatocellular carcinoma cells by increasing autocrine/paracrine canonical Wnt signaling. Coimmunoprecipitation experiments showed that GPC3 is able to form complexes with Wnts, and cell-binding assays indicated that GPC3-expressing cells have an increased capacity to bind Wnt. Collectively, these results suggest that GPC3 stimulates Wnt activity by facilitating the interaction of this polypeptide with its signaling receptors. Surprisingly, in contrast to the current model that proposes that Wnt-glypican binding is mediated by the heparan sulfate chains, we found that the nonglycanated GPC3 core protein can form complexes with Wnts. Furthermore, we showed that the glycosaminoglycan chains are not required for the stimulatory effect on Wnt signaling and hepatocellular carcinoma growth.
Kinase-Inactive Glycogen Synthase Kinase 3β Promotes Wnt Signaling and Mammary Tumorigenesis
Cancer Research, 2005
Recent studies have implicated ectopic activation of the Wnt pathway in many human cancers, including breast cancer. B-catenin is a critical coactivator in this signaling pathway and is regulated in a complex fashion by phosphorylation, degradation, and nuclear translocation. Glycogen synthase kinase 3B (GSK3B) phosphorylation of the NH 2-terminal domain of B-catenin targets it for ubiquitination and proteosomal degradation. We hypothesized that expression of kinase-inactive GSK3B (KI-GSK3B) in mammary glands would function in a dominant-negative fashion by antagonizing the endogenous activity of GSK3B and promoting breast cancer development. Consistent with this, we find that KI-GSK3B stabilizes B-catenin expression, catalyzes its localization to the nucleus, and up-regulates the downstream target gene, cyclin D1, in vitro. In vivo, transgenic mice overexpressing the KI-GSK3B under the control of the mouse mammary tumor virus-long terminal repeat develop mammary tumors with overexpression of B-catenin and cyclin D1. Thus, antagonism of GSK3B activity is oncogenic in the mammary epithelium; mutation or pharmacologic down-regulation of GSK3B could promote mammary tumors.
Identification of Glypican-3 as a potential metastasis suppressor gene in gastric cancer
Gastric cancer is a prevalent tumor that is usually detected at an advanced metastatic stage. Currently, standard therapies are mostly ineffective. Here, we report that Glypican-3 (GPC3) is absent in invasive tumors and metastatic lymph nodes, in particular in aggressive and highly disseminated signet ring cell carcinomas. We demonstrate that loss of GPC3 correlates with poor overall survival in patients. Moreover, we show that absence of GPC3 causes up-regulation of MAPK/FoxM1 signaling and that blockade of this pathway alters cellular invasion. An inverse correlation between GPC3 and FoxM1 is also shown in patient samples. These data identify GPC3 as a potential metastasis suppressor gene and suggest its value as a prognostic marker in gastric cancer. Development of therapies targeting signaling downstream of GPC3 are warranted.
Kinase-Inactive Glycogen Synthase Kinase 3B Promotes Wnt Signaling and Mammary Tumorigenesis
2005
Recent studies have implicated ectopic activation of the Wnt pathway in many human cancers, including breast cancer. B-catenin is a critical coactivator in this signaling pathway and is regulated in a complex fashion by phosphorylation, degradation, and nuclear translocation. Glycogen synthase kinase 3B (GSK3B) phosphorylation of the NH2-terminal domain of B-catenin targets it for ubiquitination and proteosomal degradation. We hypothesized that expression of kinase-inactive GSK3B (KI-GSK3B) in mammary glands would function in a dominant-negative fashion by antago- nizing the endogenous activity of GSK3B and promoting breast cancer development. Consistent with this, we find that KI-GSK3B stabilizes B-catenin expression, catalyzes its localization to the nucleus, and up-regulates the down- stream target gene, cyclin D1, in vitro. In vivo, transgenic mice overexpressing the KI-GSK3B under the control of the mouse mammary tumor virus-long terminal repeat develop mammary tumors with over...