Twist1-induced activation of human fibroblasts promotes matrix stiffness by upregulating palladin and collagen α1(VI).

The transcription factor Twist1 is involved in the epithelial-mesenchymal transition and contributes to cancer metastasis through mostly unknown mechanisms. In colorectal cancer, Twist1 expression is mainly restricted to the tumor stroma. We found that human fibroblast cell lines stably transfected with Twist1 acquired characteristics of activated cancer-associated fibroblasts (CAFs), such as hyperproliferation, an increased ability to migrate and an alignment of the actin cytoskeleton. Further, Twist1-activated fibroblasts promoted increased matrix stiffness. Using quantitative proteomics, we identified palladin and collagen α1(VI) as two major mediators of the Twist1 effects in fibroblast cell lines. Co-immunoprecipitation studies indicated that palladin and Twist1 interact within the nucleus, suggesting that palladin could act as a transcription regulator. Palladin was found to be more relevant for the cellular biomechanical properties, orientation and polarity, and collagen α1(VI) for the migration and invasion capacity, of Twist1-activated fibroblasts. Both palladin and collagen α1(VI) were observed to be overexpressed in colorectal CAFs and to be associated with poor colorectal cancer patient survival and relapse prediction. Our results demonstrate that Twist1-expressing fibroblasts mimic the properties of CAFs present at the tumor invasive front, which likely explains the prometastatic activities of Twist1. Twist1 appears to require both palladin and collagen α1(VI) as downstream effectors for its prometastatic effects, which could be future therapeutic targets in cancer metastasis.

Data from proteomic characterization of the role of Snail1 in murine mesenchymal stem cells and 3T3-L1 fibroblasts differentiation.

The transcription factor (TF) Snail1 is a major inducer of the epithelial-mesenchymal transition (EMT) during embryonic development and cancer progression. Ectopic expression of Snail in murine mesenchymal stem cells (mMSC) abrogated their differentiation to osteoblasts or adipocytes. We used either stable isotopic metabolic labeling (SILAC) for 3T3-L1 cells or isobaric labeling with tandem mass tags (TMT) for mMSC stably transfected cells with Snail1 or control. We carried out a proteomic analysis on the nuclear fraction since Snail is a nuclear TF that mediates its effects mainly through the regulation of other TFs. Proteomics data have been deposited in ProteomeXchange via the PRIDE partner repository with the dataset identifiers PXD001529 and PXD002157 (Vizcaino et al., 2014) [1]. Data are associated with a research article published in Molecular and Cellular Proteomics (Pelaez-Garcia et al., 2015) [2].

Cadherin-17 interacts with α2ß1 integrin to regulate cell proliferation and adhesion in colorectal cancer cells causing liver metastasis.

Liver metastasis is the major cause of death associated to colorectal cancer. Cadherin-17 (CDH17) is a non-classical, seven domain, cadherin lacking the conserved cytoplasmic domain of classical cadherins. CDH17 was overexpressed in highly metastatic human KM12SM and present in many other colorectal cancer cells. Using tissue microarrays, we observed a significant association between high expression of CDH17 with liver metastasis and poor survival of the patients. On the basis of these findings, we decided to study cellular functions and signaling mechanisms mediated by CDH17 in cancer cells. In this report, loss-of-function experiments demonstrated that CDH17 caused a significant increase in KM12SM cell adhesion and proliferation. Coimmunoprecipitation experiments demonstrated an interaction between CDH17 and α2ß1 integrin with a direct effect on ß1 integrin activation and talin recruitment. The formation of this complex, together with other proteins, was confirmed by mass spectrometry analysis. CDH17 modulated integrin activation and signaling to induce specific focal adhesion kinase and Ras activation, which led to the activation of extracellular signal-regulated kinase and Jun N-terminal kinase and the increase in cyclin D1 and proliferation. In vivo experiments showed that CDH17 silencing in KM12 cells suppressed tumor growth and liver metastasis after subcutaneous or intrasplenic inoculation in nude mice. Collectively, our data reveal a new function for CDH17, which is to regulate α2ß1 integrin signaling in cell adhesion and proliferation in colon cancer cells for liver metastasis.

Description of a monomeric prototype galectin from the lizard Podarcis hispanica.

Galectins are a continuously expanding family of beta-galactoside-binding lectins present in a variety of evolutionarily divergent animal species. Here we report, for the first time, that expression of galectins extends to the reptilia lineage of lizards. Up to five lactose-binding proteins were isolated from the lizard Podarcis hispanica by affinity chromatography on asialofetuin-Sepharose. The main component, which is most abundantly expressed in skin, was purified from this tissue and further characterized. Under native conditions the protein behaved as a monomer with a molecular mass of 14,500 Da and an isoelectric point of 6.3. Based on sequence homology of the 58 N-terminal amino acid residues with galectins, and on its demonstrated galactoside-binding activity, this lectin we named LG-14 (from Lizard Galectin and 14 kDa) is classified as a new member of the galectin family. LG-14 falls into and strengthen the still thinly populated category of monomeric prototype galectins.