Porcine-derived collagen peptides promote re-epithelialisation through activation of integrin signalling

\ua9 2024 The Authors. Wound Repair and Regeneration published by Wiley Periodicals LLC on behalf of The Wound Healing Society.Chronic non-healing cutaneous wounds represent a major burden to patients and healthcare providers worldwide, emphasising the continued unmet need for credible and efficacious therapeutic approaches for wound healing. We have recently shown the potential for collagen peptides to promote proliferation and migration during cutaneous wound healing. In the present study, we demonstrate that the application of porcine-derived collagen peptides significantly increases keratinocyte and dermal fibroblast expression of integrin α2β1 and activation of an extracellular signal-related kinase (ERK)-focal adhesion kinase (FAK) signalling cascade during wound closure in vitro. SiRNA-mediated knockdown of integrin β1 impaired porcine-derived collagen peptide-induced wound closure and activation of ERK-FAK signalling in keratinocytes but did not impair ERK or FAK signalling in dermal fibroblasts, implying the activation of differing downstream signalling pathways. Studies in ex vivo human 3D skin equivalents subjected to punch biopsy-induced wounding confirmed the ability of porcine-derived collagen peptides to promote wound closure by enhancing re-epithelialisation. Collectively, these data highlight the translational and clinical potential for porcine-derived collagen peptides as a viable therapeutic approach to promote re-epithelialisation of superficial cutaneous wounds

E-cadherin and loss of heterozygosity at chromosome 16 in breast carcinogenesis: different genetic pathways in ductal and lobular breast cancer?

Loss of heterozygosity at the long arm of chromosome 16 is one of the most frequent genetic events in breast cancer. In the search for tumour suppressor genes that are the target of loss of heterozygosity at 16q, the E-cadherin gene CDH1 was unveiled by the identification of truncating mutations in the retained copy. However, only lobular tumours showed E-cadherin mutations. Whereas investigations are still devoted to finding the target genes in the more frequent ductal breast cancers, other studies suspect the E-cadherin gene to also be the target in this tumour type. The present article discusses the plausibility of those two lines of thought

Insulin-like growth factor I activates the invasion suppressor function of E-cadherin in MCF-7 human mammary carcinoma cells in vitro.

The calcium-dependent cell-cell adhesion molecule E-cadherin has been shown to counteract invasion of epithelial neoplastic cells. Using three monoclonal antibodies, we have demonstrated the presence of E-cadherin at the surface of human MCF-7/6 mammary carcinoma cells by indirect immunofluorescence coupled to flow cytometry and by immunocytochemistry. Nevertheless, MCF-7/6 cells failed to aggregate in a medium containing 1.25 mM CaCl2, and they were invasive after confrontation with embryonic chick heart fragments in organ culture. Treatment of MCF-7/6 cells with 0.5 microgram ml-1 insulin-like growth factor I (IGF-I) led to homotypic aggregation within 5 to 10 min and inhibited invasion in vitro during at least 8 days. The effect of IGF-I on cellular aggregation was insensitive to cycloheximide. However, monoclonal antibodies that interfered with the function of either the IGF-I receptor (alpha IR3) or E-cadherin (HECD-1, MB2) blocked the effect of IGF-I on aggregation. The effects of IGF-I on aggregation and on invasion could be mimicked by 1 microgram ml-1 insulin, but not by 0.5 microgram ml-1 IGF-II. The insulin effects were presumably not mediated by the IGF-I receptor, since they could not be blocked by an antibody against this receptor (alpha IR3). Our results indicate that IGF-I activates the invasion suppressor role of E-cadherin in MCF-7/6 cells

TGF-beta 1 induces human alveolar epithelial to mesenchymal cell transition (EMT)

Background: Fibroblastic foci are characteristic features in lung parenchyma of patients with idiopathic pulmonary fibrosis (IPF). They comprise aggregates of mesenchymal cells which underlie sites of unresolved epithelial injury and are associated with progression of fibrosis. However, the cellular origins of these mesenchymal phenotypes remain unclear. We examined whether the potent fibrogenic cytokine TGF-β1 could induce epithelial mesenchymal transition (EMT) in the human alveolar epithelial cell line, A549, and investigated the signaling pathway of TGF-β1-mediated EMT. Methods: A549 cells were examined for evidence of EMT after treatment with TGF-β1. EMT was assessed by: morphology under phase-contrast microscopy; Western analysis of cell lysates for expression of mesenchymal phenotypic markers including fibronectin EDA (Fn-EDA), and expression of epithelial phenotypic markers including E-cadherin (E-cad). Markers of fibrogenesis, including collagens and connective tissue growth factor (CTGF) were also evaluated by measuring mRNA level using RT-PCR, and protein by immunofluorescence or Western blotting. Signaling pathways for EMT were characterized by Western analysis of cell lysates using monoclonal antibodies to detect phosphorylated Erk1/2 and Smad2 after TGF-β1 treatment in the presence or absence of MEK inhibitors. The role of Smad2 in TGF-β1-mediated EMT was investigated using siRNA. Results: The data showed that TGF-β1, but not TNF-α or IL-1β, induced A549 cells with an alveolar epithelial type II cell phenotype to undergo EMT in a time-and concentration-dependent manner. The process of EMT was accompanied by morphological alteration and expression of the fibroblast phenotypic markers Fn-EDA and vimentin, concomitant with a downregulation of the epithelial phenotype marker E-cad. Furthermore, cells that had undergone EMT showed enhanced expression of markers of fibrogenesis including collagens type I and III and CTGF. MMP-2 expression was also evidenced. TGF-β1-induced EMT occurred through phosphorylation of Smad2 and was inhibited by Smad2 gene silencing; MEK inhibitors failed to attenuate either EMT-associated Smad2 phosphorylation or the observed phenotypic changes. Conclusion: Our study shows that TGF-β1 induces A549 alveolar epithelial cells to undergo EMT via Smad2 activation. Our data support the concept of EMT in lung epithelial cells, and suggest the need for further studies to investigate the phenomenon

CDH1 gene mutations do not contribute in hereditary diffuse gastric cancer in Poland

Hereditary diffuse gastric cancer (HDGC) is a cancer susceptibility syndrome characterized by a high risk of diffuse stomach cancer and lobular breast cancer. HDGC is caused by germline mutations in the CDH1 gene encoding the E-cadherin which is a member of the transmembrane glycoprotein family responsible for calcium-dependent, cell-to-cell adhesion and plays a fundamental role in the maintenance of cell differentiation and the normal architecture of epithelial tissues. Mutations in the CDH1 gene are detected in 30–46% of families that fulfil strong clinical criteria for HDGC and in about 11% of families fulfilling the modified criteria. In the present study, we investigated germline mutations in the CDH1 gene in Polish patients with HDGC. The entire coding sequence of CDH1 gene was analyzed by sequencing in 86 Polish cancer patients from families fulfilling the modified criteria of HDGC. We found several silent mutations including one common variant (c.2076T>C) present in 56 patients, and three rare variants (c.2253C>T, c.1896C>T, c.2634C>T) detected in 2 patients. In addition, we found four rare sequence variants of unknown significance localized in introns. We did not detect any deleterious mutations of the CDH1 gene. CDH1 gene mutations are not present in Polish families with HDGC defined by the modified clinical criteria. Further studies of families with HDGC matching the restrictive criteria for HDGC are needed

Structure-Property Optimization of a Series of Imidazopyridines for Visceral Leishmaniasis

Leishmaniasis is a collection of diseases caused by more than 20 Leishmania parasite species that manifest as either visceral, cutaneous, or mucocutaneous leishmaniasis. Despite the significant mortality and morbidity associated with leishmaniasis, it remains a neglected tropical disease. Existing treatments have variable efficacy, significant toxicity, rising resistance, and limited oral bioavailability, which necessitates the development of novel and affordable therapeutics. Here, we report on the continued optimization of a series of imidazopyridines for visceral leishmaniasis and a scaffold hop to a series of substituted 2-(pyridin-2-yl)-6,7-dihydro-5H-pyrrolo[1,2-a]imidazoles with improved absorption, distribution, metabolism, and elimination properties

Genetic Deletion of the Desmosomal Component Desmoplakin Promotes Tumor Microinvasion in a Mouse Model of Pancreatic Neuroendocrine Carcinogenesis

We used the RIP1-Tag2 (RT2) mouse model of islet cell carcinogenesis to profile the transcriptome of pancreatic neuroendocrine tumors (PNET) that were either non-invasive or highly invasive, seeking to identify pro- and anti-invasive molecules. Expression of multiple components of desmosomes, structures that help maintain cellular adhesion, was significantly reduced in invasive carcinomas. Genetic deletion of one of these desmosomal components, desmoplakin, resulted in increased local tumor invasion without affecting tumor growth parameters in RT2 PNETs. Expression of cadherin 1, a component of the adherens junction adhesion complex, was maintained in these tumors despite the genetic deletion of desmoplakin. Our results demonstrate that loss of desmoplakin expression and resultant disruption of desmosomal adhesion can promote increased local tumor invasion independent of adherens junction status

Alterations of E-cadherin and β-catenin in gastric cancer

BACKGROUND: The E-cadherin-catenin complex plays a crucial role in epithelial cell-cell adhesion and in the maintenance of tissue architecture. Perturbation in the expression or function of this complex results in loss of intercellular adhesion, with possible consequent cell transformation and tumour progression. METHODS: We studied the alterations of E-cadherin and β-catenin in a set of 50 primary gastric tumours by using loss of heterozygosity (LOH) analysis, gene mutation screening, detection of aberrant transcripts and immunohistochemistry (IHC). RESULTS: A high frequency (75%) of LOH was detected at 16q22.1 containing E-cadherin locus. Three cases (6%) showed the identical missense mutation, A592T. This mutation is not likely to contribute strongly to the carcinogenesis of gastric cancer, because a low frequency (1.6%) of this mutation was also found in 187 normal individuals. We also detected a low frequency (0.36%, 0%) of this mutation in 280 breast tumours and 444 other tumours, including colon and rectum, lung, endometrium, ovary, testis, kidney, thyroid carcinomas and sarcomas, respectively. We also analyzed the aberrant E-cadherin mRNAs in the gastric tumours and found that 7 tumours (18%) had aberrant mRNAs in addition to the normal mRNA. These aberrant mRNAs may produce abnormal E-cadherin molecules, resulting in weak cell-cell adhesion and invasive behaviour of carcinoma cells. Reduced expression of E-cadherin and β-catenin was identified at the frequency of 42% and 28%, respectively. Specially, 11 tumours (22%) exhibited positive cytoplasmic staining for β-catenin IHC. An association was found between reduced expression of E-cadherin and β-catenin. Moreover, an association was detected between reduced expression of E-cadherin and diffuse histotype. CONCLUSION: Our results support the hypothesis that alterations of E-cadherin and β-catenin play a role in the initiation and progression of gastric cancer

Imaging the Impact of Chemically Inducible Proteins on Cellular Dynamics In Vivo

The analysis of dynamic events in the tumor microenvironment during cancer progression is limited by the complexity of current in vivo imaging models. This is coupled with an inability to rapidly modulate and visualize protein activity in real time and to understand the consequence of these perturbations in vivo. We developed an intravital imaging approach that allows the rapid induction and subsequent depletion of target protein levels within human cancer xenografts while assessing the impact on cell behavior and morphology in real time. A conditionally stabilized fluorescent E-cadherin chimera was expressed in metastatic breast cancer cells, and the impact of E-cadherin induction and depletion was visualized using real-time confocal microscopy in a xenograft avian embryo model. We demonstrate the assessment of protein localization, cell morphology and migration in cells undergoing epithelial-mesenchymal and mesenchymal-epithelial transitions in breast tumors. This technique allows for precise control over protein activity in vivo while permitting the temporal analysis of dynamic biophysical parameters

A comparative evaluation of various invasion assays testing colon carcinoma cell lines

Various colon carcinoma cell lines were tested in different invasion assays, i.e. invasion into Matrigel, into confluent fibroblast layers and into chicken heart tissue. Furthermore, invasive capacity and metastatic potential were determined in nude mice. The colon carcinoma cells used were the human cell lines Caco-2, SW-480, SW-620 and HT-29, and the murine lines Colon-26 and -38. None of the human colon carcinoma cells migrated through porous membranes coated with Matrigel; of the murine lines, only Colon-26 did. When incubated in a mixture of Matrigel and culture medium non-invading cells formed spheroid cultures, whereas invading cells showed a stellate outgrowth. Only the heterogeneously shaped (epithelioid and stellate) cells of SW-480 and SW-620 and the spindle-shaped cells of Colon-26 invaded clearly confluent skin and colon fibroblasts as well as chicken heart tissue. However, when transplanted into the caecum of nude and syngeneic mice, all the lines tested were invasive with the exception of Caco-2 cells. We conclude that the outcome of in vitro tests measuring the invasive capacity of neoplastic cells is largely dependent on the test system used. Invasive capacity in vitro is strongly correlated with cells having a spindle cell shape, vimentin expression and E-cadherin down regulation. In contrast, HT-29 and Colon-38 cells having an epithelioid phenotype were clearly invasive and metastatic in vivo, but not in vitro. © 1999 Cancer Research Campaig