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.

The in vitro cytotoxic activity on human cancer cell lines of sixteen commercial EOs such as Aloysia citriodora, Boswellia sacra, Boswellia serrata, Cinnamomum zeylanicum, Cistus ladanifer, Citrus × aurantium, Citrus limon, Citrus sinensis, Cymbopogon citratus, Foeniculum vulgare, Illicium verum, Litsea cubeba, Satureja montana, Syzygium aromaticum, Thymus capitatus and Thymus vulgaris was performed using the MTT reduction assay. The screening was carried out on human cancer cells of breast adenocarcinoma (MCF7, T47D and MDA-MB-231), chronic myelogenous erythroleukemia (K562) and neuroblastoma cell lines (SH-SY5Y). C. zeylanicum and L. cubeba EOs were the most active on almost all the cell lines studied and thus could be promising as an anticancer agent. These two species showed a difference in their composition even though they belong to the Lauraceae family. Almost 57 % of the true cinnamon composition was made of (E)-cinnamaldehyde, while L. cubeba showed citral as the major compound (68.9 %). The K562 cells were the most sensitive to these oils with an IC 50 ranging from 5.2 parts-per million (ppm) (C. zeylanicum) to 11.1 ppm (L. cubeba). The latter oil also showed an important cytotoxicity on MDA-MB-231 (13.4 ppm).

No abstract

In human breast cancer, β-catenin localization has been related with disease prognosis. Since HER2-positive patients are an important subgroup, and that in breast cancer cells a direct interaction of β-catenin/HER2 has been reported, in the present study we have explored whether β-catenin location is related with the disease survival. The study was performed in a tumor bank from patients (n = 140) that did not receive specific anti-HER2 therapy. The proteins were detected by immunohistochemistry in serial sections, 47 (33.5%) patients were HER2-positive with a long follow-up. HER2-positive patients that displayed β-catenin at the plasma membrane (completely surrounding the tumour cells) showed a significant better disease-free survival and overall survival than the patients showing the protein on other locations. Then we explored the dynamics of the co-expression of β-catenin and HER2 in human MCF-7 and SKBR3 cells exposed to different stressful situations. In untreated conditions MCF-7 and SKBR3 cells showed very different β-catenin localization. In MCF-7 cells, cadmium administration caused a striking change in β-catenin localization driving it from plasma membrane to cytoplasmic and perinuclear areas and HER2 showed a similar localization patterns. The changes induced by cadmium were compared with heat shock, H2O2 and tamoxifen treatments. In conclusion, this study shows the dynamical associations of HER2 and β-catenin and their changes in subcellular localizations driven by stressful situations. In addition, we report for the first time the correlation between plasma membrane associated β-catenin in HER2-positive breast cancer and survival outcome, and the importance of the protein localization in breast cancer samples.