Patricia de Winter

Connective tissue growth factor: Structure-function relationships of a mosaic, multifunctional protein

Connective tissue growth factor (CTGF) is a member of the CCN family of six small secreted, cysteine-rich growth factors. The unique modular structure encompasses distinct functional domains which enable CTGF to interact with growth factors, surface receptors and matrix components. Widely expressed, CTGF has critical roles in embryonic development and the maintenance of normal cell and connective tissue function. It is also important for tissue repair following injury, and has been implicated in common diseases including atherosclerosis, pulmonary and renal fibrotic disorders and cancer. Factors that regulate CTGF transcription in response to exogenous stimuli, as well as downstream signalling pathways, have been described. However, only recently have studies begun to unravel how the functional domains within the CTGF modules orchestrate signals and control key biological processes. This article highlights how the structural and functional domains of CTGF and CTGF cleavage fragments integrate multiple extracellular events into cell signals.

Epithelial Cells Promote Fibroblast Activation via IL-1α in Systemic Sclerosis

Systemic sclerosis (SSc) is a disorder of systemic and dermal fibrosis of uncertain etiology. Recently, we found that SSc epidermis is abnormal, taking on an activated phenotype observed during wound healing and tissue repair. As epithelial-fibroblast interactions are important during wound repair and in fibrosis in general, we investigated further the phenotype of the SSc epidermis, and tested whether the SSc epidermis provides a pro-fibrotic stimulus to fibroblasts. In this study we show that in SSc epidermis keratinocyte maturation is delayed, and wound-associated keratins 6 and 16 are induced, in both involved and clinically uninvolved skin. Phosphorylation array analysis revealed induction of stress-induced mitogen-activated protein kinase signaling and mesenchymal feedback through hepatocyte growth factor/c-Met in SSc epidermis. SSc epidermal cells maintained with normal fibroblasts in three-dimensional co-culture were found to stimulate fibroblasts, leading to contractility and connective tissue growth factor expression. These effects depend on elevation of IL-1alpha by the epidermal cells and induction of endothelin-1 and transforming growth factor-beta in fibroblasts. Antagonism of endogenous IL-1alpha using IL-1 receptor antagonist blocked gel contraction by SSc epidermis. We propose that in SSc, epidermal cells are in a persistently activated state and are able to promote dermal fibrosis. These findings are important because biologic therapies could target epithelial-fibroblast interactions in the disease.

An Ongoing Role of α-Calcitonin Gene–Related Peptide as Part of a Protective Network Against Hypertension, Vascular Hypertrophy, and Oxidative Stress

&agr;-Calcitonin gene–related peptide (&agr;CGRP) is a vasodilator, but there is limited knowledge of its long-term cardiovascular protective influence. We hypothesized that &agr;CGRP protects against the onset and development of angiotensin II–induced hypertension and have identified protective mechanisms at the vascular level. Wild-type and &agr;CGRP knockout mice that have similar baseline blood pressure were investigated in the angiotensin II hypertension model for 14 and 28 days. &agr;CGRP knockout mice exhibited enhanced hypertension and aortic hypertrophy. &agr;CGRP gene expression was increased in dorsal root ganglia and at the conduit and resistance vessel level of wild-type mice at both time points. &bgr;CGRP gene expression was also observed and shown to be linked to plasma levels of CGRP. Mesenteric artery contractile and relaxant responses in vitro and endothelial NO synthase expression were similar in all groups. The aorta exhibited vascular hypertrophy, increased collagen formation, and oxidant stress markers in response to angiotensin II, with highest effects observed in &agr;CGRP knockout mice. Gene and protein expression of endothelial NO synthase was lacking in the aortae after angiotensin II treatment, especially in &agr;CGRP knockout mice. These results demonstrate the ongoing upregulation of &agr;CGRP at the levels of both conduit and resistance vessels in vascular tissue in a model of hypertension and the direct association of this with protection against aortic vascular hypertrophy and fibrosis. This upregulation is maintained at a time when expression of aortic endothelial NO synthase and antioxidant defense genes have subsided, in keeping with the concept that the protective influence of &agr;CGRP in hypertension may have been previously underestimated.

Epigenetics Markers of Metastasis and HPV-Induced Tumorigenesis in Penile Cancer

Purpose: Penile cancer is a rare malignancy in the developed world with just more than 1,600 new cases diagnosed in the United States per year; however, the incidence is much higher in developing countries. Although HPV is known to contribute to tumorigenesis, little is known about the genetic or epigenetic alterations defining penile cancer. Experimental Design: Using high-density genome-wide methylation arrays, we have identified epigenetic alterations associated with penile cancer. Q-MSP was used to validate lymph node metastasis markers in 50 cases. A total of 446 head and neck squamous cell carcinoma (HNSCC) and cervical squamous cell carcinoma (CESCC) samples were used to validate HPV-associated epigenetic alterations. Results: We defined 6,933 methylation variable positions (MVP) between normal and tumor tissue, which includes 997 hypermethylated differentially methylated regions associated with tumor supressor genes, including CDO1, AR1, and WT1. Analysis of penile cancer tumors identified a 4 gene epi-signature which accurately predicted lymph node metastasis in an independent cohort (AUC of 89%). Finally, we explored the epigenetic alterations associated with penile cancer HPV infection and defined a 30 loci lineage-independent HPV specific epi-signature which predicts HPV status and survival in independent HNSCC, CESC cohorts. Epi-signature–negative patients have a significantly worse overall survival [HNSCC P = 0.00073; 95% confidence interval (CI), 0.021–0.78; CESC P = 0.0094; HR = 3.91, 95% CI = 0.13–0.78], HPV epi-signature is a better predictor of survival than HPV status alone. Conclusions: These data demonstrate for the first time genome-wide epigenetic events involved in an aggressive penile cancer phenotype and define the epigenetic alterations common across multiple HPV-driven malignancies. Clin Cancer Res; 21(5); 1196–206. ©2014 AACR.