Browsing by Author "Varas-Godoy, Manuel"
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Item Caveolin-1-containing extracellular vesicles transport adhesion proteins and promote malignancy in breast cancer cell lines(Future Medicine Ltd, 2018) Campos, America; Salomon, Carlos; Bustos, Rocío; Díaz, Jorge; Martínez, Samuel; Silva, Verónica; Reyes, Constanza; Díaz-Valdivia, Natalia; Varas-Godoy, Manuel; Lobos-González, Lorena; Quest, AndrewBreast cancer is one of the most frequently diagnosed cancers and the leading cause of cancer-related deaths in women worldwide, whereby mortality is largely attributable to the development of distant metastasis. Caveolin-1 (CAV1) is a multifunctional membrane protein that is typically upregulated in the final stages of cancer and promotes migration and invasion of tumor cells. Elevated levels of CAV1 have been detected in extracellular vesicles (EVs) from advanced cancer patients. EVs are lipid enclosed vesicular structures that contain bioactive proteins, DNA and RNAs, which can be transferred to other cells and promote metastasis. Therefore, we hypothesized that CAV1 containing EVs released from breast cancer cells may enhance migration and invasion of recipient cells. EVs were purified from conditioned media of MDA-MB-231 wild-type (WT), MDA-MB-231 (shCAV1; possessing the plasmid pLKO.1 encoding a 'small hairpin' directed against CAV1) and MDA-MB-231 (shC) short hairpin control cells. Nanoparticle tracking analysis revealed an average particle size of 40-350 nm for all preparations. As anticipated, CAV1 was detected in MDA-MB-231 WT and shC EVs, but not in MDA-MB-231 (shCAV1) EVs. Mass spectrometry analysis revealed the presence of specific cell adhesion-related proteins, such as Cyr61, tenascin (TNC) and S100A9 only in WT and shC, but not in shCAV1 EVs. Importantly, EVs containing CAV1 promoted migration and invasion of cells lacking CAV1. We conclude that the presence of CAV1 in EVs from metastatic breast cancer cells is associated with enhanced migration and invasiveness of recipient cells in vitro, suggesting that intercellular communication promoted by EVs containing CAV1 will likely favor metastasis in vivo.Item Connexin-46 Contained in Extracellular Vesicles Enhance Malignancy Features in Breast Cancer Cells(2020) Acuña, Rodrigo; Varas-Godoy, Manuel; Berthoud, Viviana M.; Alfaro, Iván; Retamal, Mauricio A.Under normal conditions, almost all cell types communicate with their neighboring cells through gap junction channels (GJC), facilitating cellular and tissue homeostasis. A GJC is formed by the interaction of two hemichannels; each one of these hemichannels in turn is formed by six subunits of transmembrane proteins called connexins (Cx). For many years, it was believed that the loss of GJC-mediated intercellular communication was a hallmark in cancer development. However, nowadays this paradigm is changing. The connexin 46 (Cx46), which is almost exclusively expressed in the eye lens, is upregulated in human breast cancer, and is correlated with tumor growth in a Xenograft mouse model. On the other hand, extracellular vesicles (EVs) have an important role in long-distance communication under physiological conditions. In the last decade, EVs also have been recognized as key players in cancer aggressiveness. The aim of this work was to explore the involvement of Cx46 in EV-mediated intercellular communication. Here, we demonstrated for the first time, that Cx46 is contained in EVs released from breast cancer cells overexpressing Cx46 (EVs-Cx46). This EV-Cx46 facilitates the interaction between EVs and the recipient cell resulting in an increase in their migration and invasion properties. Our results suggest that EV-Cx46 could be a marker of cancer malignancy and open the possibility to consider Cx46 as a new therapeutic target in cancer treatment.Item Connexin46 Expression Enhances Cancer Stem Cell and Epithelial-to-Mesenchymal Transition Characteristics of Human Breast Cancer MCF-7 Cells(2021) Acuña, Rodrigo; Varas-Godoy, Manuel; Herrera-Sepúlveda, Diego; Retamal, MauricioConnexins (Cxs) are a family of proteins that form two different types of ion channels: hemichannels and gap junction channels. These channels participate in cellular communication, enabling them to share information and act as a synchronized syncytium. This cellular communication has been considered a strong tumor suppressor, but it is now recognized that some type of Cxs can be pro-tumorigenic. For example, Cx46 expression is increased in human breast cancer samples and correlates with cancer stem cell (CSC) characteristics in human glioma. Thus, we explored whether Cx46 and glioma cells, can set up CSC and epithelial-to-mesenchymal transition (EMT) properties in a breast cancer cell line. To this end, we transfected MCF-7 cells with Cx46 attached to a green fluorescent protein (Cx46GFP), and we determined how its expression orchestrates both the gene-expression and functional changes associated with CSC and EMT. We observed that Cx46GFP increased Sox2, Nanog, and OCT4 mRNA levels associated with a high capacity to form monoclonal colonies and tumorspheres. Similarly, Cx46GFP increased the mRNA levels of n-cadherin, Vimentin, Snail and Zeb1 to a higher migratory and invasive capacity. Furthermore, Cx46GFP transfected in MCF-7 cells induced the release of higher amounts of VEGF, which promoted angiogenesis in HUVEC cells. We demonstrated for the first time that Cx46 modulates CSC and EMT properties in breast cancer cells and thus could be relevant in the design of future cancer therapiesItem Exosomes released upon mitochondrial ASncmtRNA knockdown reduce tumorigenic properties of malignant breast cancer cells.(Nature Publishing Group, 2020) Lobos-González, Lorena; Bustos, Rocío; Campos, América; Silva, Valeria; Silva, Verónica; Jeldes, Emanuel; Salomon, Carlos; Varas-Godoy, Manuel; Cáceres-Verschae, Albano; Durán, Eduardo; Vera, Tamara; Ezquer, Fernando; Ezquer, Marcelo; Burzio, Verónica; Villegas, JaimeDuring intercellular communication, cells release extracellular vesicles such as exosomes, which contain proteins, ncRNAs and mRNAs that can influence proliferation and/or trigger apoptosis in recipient cells, and have been proposed to play an essential role in promoting invasion of tumor cells and in the preparation of metastatic niches. Our group proposed the antisense non-coding mitochondrial RNA (ASncmtRNA) as a new target for cancer therapy. ASncmtRNA knockdown using an antisense oligonucleotide (ASO-1537S) causes massive death of tumor cells but not normal cells and strongly reduces metastasis in mice. In this work, we report that exosomes derived from ASO-1537S-treated MDA-MB-231 breast cancer cells (Exo-1537S) inhibits tumorigenesis of recipient cells, in contrast to exosomes derived from control-ASO-treated cells (Exo-C) which, in contrast, enhance these properties. Furthermore, an in vivo murine peritoneal carcinomatosis model showed that Exo-1537S injection reduced tumorigenicity compared to controls. Proteomic analysis revealed the presence of Lactadherin and VE-Cadherin in exosomes derived from untreated cells (Exo-WT) and Exo-C but not in Exo-1537S, and the latter displayed enrichment of proteasomal subunits. These results suggest a role for these proteins in modulation of tumorigenic properties of exosome-recipient cells. Our results shed light on the mechanisms through which ASncmtRNA knockdown affects the preparation of breast cancer metastatic niches in a peritoneal carcinomatosis model.Item Frizzled-1 receptor regulates adult hippocampal neurogenesis(BioMed Central, 2016) Mardones, Muriel; Andaur, Gabriela; Varas-Godoy, Manuel; Henriquez, Jenny; Salech, Felipe; Behrens, María Isabel; Couve, Andres; Inestrosa, Nibaldo; Varela-Nallar, LorenaBACKGROUND: In the adult hippocampus new neurons are continuously generated from neural stem cells (NSCs) present at the subgranular zone of the dentate gyrus. This process is controlled by Wnt signaling, which plays a complex role in regulating multiple steps of neurogenesis including maintenance, proliferation and differentiation of progenitor cells and the development of newborn neurons. Differential effects of Wnt signaling during progression of neurogenesis could be mediated by cell-type specific expression of Wnt receptors. Here we studied the potential role of Frizzled-1 (FZD1) receptor in adult hippocampal neurogenesis. RESULTS: In the adult dentate gyrus, we determined that FZD1 is highly expressed in NSCs, neural progenitors and immature neurons. Accordingly, FZD1 is expressed in cultured adult hippocampal progenitors isolated from mouse brain. To evaluate the role of this receptor in vivo we targeted FZD1 in newborn cells using retroviral-mediated RNA interference. FZD1 knockdown resulted in a marked decrease in the differentiation of newborn cells into neurons and increased the generation of astrocytes, suggesting a regulatory role for the receptor in cell fate commitment. In addition, FZD1 knockdown induced an extended migration of adult-born neurons within the granule cell layer. However, no differences were observed in total dendritic length and dendritic arbor complexity between control and FZD1-deficient newborn neurons. CONCLUSIONS: Our results show that FZD1 regulates specific stages of adult hippocampal neurogenesis, being required for neuronal differentiation and positioning of newborn neurons into the granule cell layer, but not for morphological development of adult-born granule neurons.Item Small Extracellular Vesicles Released from Ovarian Cancer Spheroids in Response to Cisplatin Promote the Pro-Tumorigenic Activity of Mesenchymal Stem Cells(MDPI, 2019) Vera, Nelly; Acuña-Gallardo, Stephanie; Grünenwald, Felipe; Cáceres-Verschae, Albano; Realini, Ornela; Acuña, Rodrigo; Lladser, Álvaro; Illanes, Sebastián; Varas-Godoy, ManuelDespite the different strategies used to treat ovarian cancer, around 70% of women/patients eventually fail to respond to the therapy. Cancer stem cells (CSCs) play a role in the treatment failure due to their chemoresistant properties. This capacity to resist chemotherapy allows CSCs to interact with different components of the tumor microenvironment, such as mesenchymal stem cells (MSCs), and thus contribute to tumorigenic processes. Although the participation of MSCs in tumor progression is well understood, it remains unclear how CSCs induce the pro-tumorigenic activity of MSCs in response to chemotherapy. Small extracellular vesicles, including exosomes, represent one possible way to modulate any type of cell. Therefore, in this study, we evaluate if small extracellular vesicle (sEV) derived from ovarian cancer spheroids (OCS), which are enriched in CSCs, can modify the activity of MSCs to a pro-tumorigenic phenotype. We show that sEV released by OCS in response to cisplatin induce an increase in the migration pattern of bone marrow MSCs (BM-MSCs) and the secretion interleukin-6 (IL-6), interleukin-8 (IL-8), and vascular endothelial growth factor A (VEGFA). Moreover, the factors secreted by BM-MSCs induce angiogenesis in endothelial cells and the migration of low-invasive ovarian cancer cells. These findings suggest that cisplatin could modulate the cargo of sEV released by CSCs, and these exosomes can further induce the pro-tumorigenic activity of MSCs.