The effect of cell-matrix interactions and aging on the malignant process

A Novel Prognostic Nomogram for Predicting Risks of Distant Failure in Patients with Invasive Breast Cancer Following Postoperative Adjuvant Radiotherapy

Purpose

This study aimed to identify predictors for distant metastatic behavior and build a related prognostic nomogram in breast cancer.

Materials and Methods

A total of 1,181 patients with non-metastatic breast cancer between 2003 and 2011 were analyzed. To predict the probability of distant metastasis, a nomogram was constructed based on prognostic factors identified using a Cox proportional hazards model.

Results

The 7-year overall survival and 5-year post-progression survival of locoregional versus distant recurrence groups were 67.6% versus 39.1% (p=0.027) and 54.2% versus 33.5% (p=0.043), respectively. Patients who developed distant metastasis showed early and late mortality risk peaks within 3 and after 5 years of follow-up, respectively, but a broad and low risk increment was observed in other patients with locoregional relapse. In multivariate analysis of distant metastasis-free interval, age (≥ 45 years vs. < 45 years), molecular subtypes (luminal A vs. luminal B, human epidermal growth receptor 2, and triple negative), T category (T1 vs. T2-3 and T4), and N category (N0 vs. N1 and N2-3) were independently associated (p < 0.05 for all). Regarding the significant factors, a well-validated nomogram was established (concordance index, 0.812). The risk score level of patients with initial brain failure was higher than those of non-brain sites (p=0.029).

Conclusion

The nomogram could be useful for predicting the individual probability of distant recurrence in breast cancer. In high-risk patients based on the risk scores, more aggressive systemic therapy and closer surveillance for metastatic failure should be considered.

Cell senescence: role in aging and age-related diseases

Cell senescence is one of the major paradigms of aging research. It started with the demonstration by L. Hayflick of the limited number of divisions by normal, nontransformed cells, not shown by transformed malignant cells, this processes being largely regulated by the telomere-telomerase system. A complete renewal of this discipline came from the demonstration that cells can enter senescence at any time by an anti-oncogene-triggered pathway, enabling them to escape malignancy. The senescent cell became a major actor of the aging process, among others, by the acquisition of the senescence-associated secretory phenotype. This chapter is devoted to the regulatory process involved in the acquisition of the senescent cell phenotype and its role in organismal aging.

Tumors perturbing extracellular matrix biosynthesis. The case of von Recklinghausen's disease

This is a short review of neurofibromatosis-1 or von Recklinghausen's disease, due to a loss of function mutation of the gene neurofibromin-1, which normally inhibits the Ras MAPK-pathways. Among its symptoms, the strong oversynthesis of several collagen types designates this disease as producing a deregulation of extracellular matrix biosynthesis involved in tumor formation. Up to about 40% of the skin tumors consist of collagens. A short summary of the clinical manifestations and pathological and genetic mechanisms are also described.

The role of manganese superoxide dismutase in skin aging

The free radical theory of aging postulates that the production of mitochondrial reactive oxygen species is the major determinant of aging and lifespan. The skin represents an excellent and accessible model organ to study aging that is characterized by atrophy, wrinkle formation, reduced tensile strength and impaired wound healing. Oxidative stress as a consequence of an imbalance in prooxidants and antioxidants with increased ROS concentrations has been demonstrated in the aged skin in vitro and in vivo, suggesting the important role of the antioxidant balance. Here we will summarize recent data on the role of the mitochondrial superoxide dismutase 2 in skin aging.

[Theodor Huzella and the initiation of research on the interactions between cells and the extracellular matrix]

Interactions between cells and the surrounding "biomatrix", mediated by receptors as integrins or the elastin receptor is the most important topic in up to date research on connective tissues. Looking for the origin of this concept, one finds the pioneering work of Theodor Huzella, professor of histology-embryology at the Medical University of Budapest during pre-world war II decades. Using time-laps micro-cinematography in reflected light, he visualized the important role of connective tissue fibers, prepared in his laboratory, for the oriented migration of normal and malignant cells. His theoretical explanations, attributing an "active" role to the elasticity of the argyrophilic fibrous network in the coordination of cell societies, can now be reinterpreted in the light of recent work on the mechanotransduction of "messages" from the extracellular matrix to the cell inside. We propose a succinct review of Huzella's work and theories reinterpreted in the light of up-to-date knowledge on cell-matrix interactions.

Physiology of skin aging

Skin is the most voluminous organ of the body. It assumes several important physiological functions and represents also a "social interface" between an individual and other members of society. This is the main reason its age-dependent modifications are in the forefront of dermatological research and of the "anti-aging" cosmetic industry. Here we concentrate on some aspects only of skin aging, as far as the cellular and extracellular matrix components of skin are concerned. Most well studied mechanisms of skin aging can be situated at the postgenetic level, both epigenetic and post-translational mechanisms being involved. Some of these mechanisms will be reviewed as well as the capacity of fucose- and rhamnose-rich oligo- and polysaccharides (FROP and RROP) to counteract several of the mechanisms involved in skin aging.

An in vitro co-culture model of esophageal cells identifies ascorbic acid as a modulator of cell competition

Background

The evolutionary dynamics between interacting heterogeneous cell types are fundamental properties of neoplastic progression but can be difficult to measure and quantify. Cancers are heterogeneous mixtures of mutant clones but the direct effect of interactions between these clones is rarely documented. The implicit goal of most preventive interventions is to bias competition in favor of normal cells over neoplastic cells. However, this is rarely explicitly tested. Here we have developed a cell culture competition model to allow for direct observation of the effect of chemopreventive or therapeutic agents on two interacting cell types. We have examined competition between normal and Barrett's esophagus cell lines, in the hopes of identifying a system that could screen for potential chemopreventive agents.

Methods

One fluorescently-labeled normal squamous esophageal cell line (EPC2-hTERT) was grown in competition with one of four Barrett's esophagus cell lines (CP-A, CP-B, CP-C, CP-D) under varying conditions and the outcome of competition measured over 14 days by flow cytometry.

Results

We demonstrate that ascorbic acid (vitamin C) can help squamous cells outcompete Barrett's cells in this system. We are also able to show that ascorbic acid's boost to the relative fitness of squamous cells was increased in most cases by mimicking the pH conditions of gastrointestinal reflux in the lower esophagus.

Conclusions

This model is able to integrate differential fitness effects on various cell types, allowing us to simultaneously capture effects on interacting cell types without having to perform separate experiments. This model system may be used to screen for new classes of cancer prevention agents designed to modulate the competition between normal and neoplastic cells.

Differential expression of extracellular matrix proteins in senescent and young human fibroblasts: a comparative proteomics and microarray study

The extracellular matrix (ECM) provides an essential structural framework for cell attachment, proliferation, and differentiation, and undergoes progressive changes during senescence. To investigate changes in protein expression in the extracellular matrix between young and senescent fibroblasts, we compared proteomic data (LTQ-FT) with cDNA microarray results. The peptide counts from the proteomics analysis were used to evaluate the level of ECM protein expression by young cells and senescent cells, and ECM protein expression data were compared with the microarray data. After completing the comparative analysis, we grouped the genes into four categories. Class I included genes with increased expression levels in both analyses, while class IV contained genes with reduced expression in both analyses. Class II and Class III contained genes with an inconsistent expression pattern. Finally, we validated the comparative analysis results by examining the expression level of the specific gene from each category using Western blot analysis and semiquantitative RT-PCR. Our results demonstrate that comparative analysis can be used to identify differentially expressed genes.

Accelerated aging phenotype in mice with conditional deficiency for mitochondrial superoxide dismutase in the connective tissue

The free radical theory of aging postulates that the production of mitochondrial reactive oxygen species is the major determinant of aging and lifespan. Its role in aging of the connective tissue has not yet been established, even though the incidence of aging-related disorders in connective tissue-rich organs is high, causing major disability in the elderly. We have now addressed this question experimentally by creating mice with conditional deficiency of the mitochondrial manganese superoxide dismutase in fibroblasts and other mesenchyme-derived cells of connective tissues in all organs. Here, we have shown for the first time that the connective tissue-specific lack of superoxide anion detoxification in the mitochondria results in reduced lifespan and premature onset of aging-related phenotypes such as weight loss, skin atrophy, kyphosis (curvature of the spine), osteoporosis and muscle degeneration in mutant mice. Increase in p16(INK4a) , a robust in vivo marker for fibroblast aging, may contribute to the observed phenotype. This novel model is particularly suited to decipher the underlying mechanisms and to develop hopefully novel connective tissue-specific anti-aging strategies.

Aging-related alterations in the extracellular matrix modulate the microenvironment and influence tumor progression

Age is the greatest risk factor for the development of epithelial cancers. In this minireview, we will examine key extracellular matrix and matricellular components, their changes with aging, and discuss how these alterations might influence the subsequent progression of cancer in the aged host. Because of the tight correlation between advanced age and the prevalence of prostate cancer, we will use prostate cancer as the model throughout this minireview.

Intact extracellular matrix and the maintenance of immune tolerance: high molecular weight hyaluronan promotes persistence of induced CD4+CD25+ regulatory T cells

The composition of the ECM provides contextual cues to leukocytes in inflamed and healing tissues. One example of this is HA, where LMW-HA, generated during active inflammation, is a TLR ligand and an endogenous "danger signal," and HMW-HA, predominant in healing or intact tissues, functions in an inverse manner. Our data suggest that HMW-HA actively promotes immune tolerance by augmenting CD4+CD25+ T(Reg) function, and LMW-HA does not. Using a human iT(Reg) model, we demonstrate that HMW-HA but not LMW-HA provides a costimulatory signal through cross-linking CD44 which promotes Foxp3 expression, a critical signaling molecule associated with T(Reg). This effect, in part, may be mediated by a role for intact HMW-HA in IL-2 production, as T(Reg) are highly IL-2-dependent for their survival and function. We propose that HMW-HA contributes to the maintenance of immune homeostasis in uninjured tissue and effectively communicates an "all-clear" signal to down-regulate the adaptive immune system through T(Reg) after tissue matrix integrity has been restored.

Overexpression of manganese superoxide dismutase in human dermal fibroblasts enhances the contraction of free floating collagen lattice: implications for ageing and hyperplastic scar formation

Cell-matrix interactions are of significant importance for tissue homeostasis of the skin and, if disturbed, may lead to ageing and hyperplastic scar formation. We have studied fibroblasts stably overexpressing manganese superoxide dismutase (MnSOD) with a defined capacity for the removal of superoxide anions and concomitant accumulation of hydrogen peroxide to evaluate the role of enhanced MnSOD activity on the dynamics of cell-matrix interactions in the three-dimensional collagen lattice contraction assay. MnSOD overexpressing fibroblast populated collagen lattices revealed a significantly enhanced contraction compared to collagen lattices populated with vector control cells. The enhanced collagen lattice contraction was in part due to an increase in active TGF-beta1 and the accumulation of H2O2 in MnSOD overexpressing fibroblasts populated collagen lattices. Inhibition of TGF-beta1 signalling by the ALK4,5,7 kinases' inhibitor SB431542 at least partly inhibited the enhanced collagen lattice contraction of MnSOD overexpressing fibroblasts populated lattices. In addition, supplementation of vector control fibroblast populated collagen lattices with recombinant TGF-beta1 concentration dependently enhanced the collagen lattice contraction. In the presence of the antioxidant Ebselen, a mimic of H2O2 and other hydroperoxides/peroxynitrite-detoxifying glutathione peroxidase, collagen lattice contraction and the activation of TGF-beta1 were significantly reduced in collagen lattices populated with MnSOD overexpressing fibroblasts. Collectively, these data suggest that H2O2 or other hydroperoxides or peroxynitrite or a combination thereof may function as important second messengers in collagen lattice contraction and act at least in part via TGF-beta1 activation.

Expression of senescence-associated beta-galactosidase (SA-beta-Gal) by human skin fibroblasts, effect of advanced glycation end-products and fucose or rhamnose-rich polysaccharides

Expression by cells of the SA-beta-Gal was shown to be a reliable indicator of the switch mechanism used by cells to enter the senescent phenotype. We used this method in order to explore the variation of SA-beta-Gal-positive cells with passage number and time spent in culture. Both parameters produced an increase of SA-beta-Gal-positive cells. The addition of a Maillard-product (advanced glycation end-product=AGE) to the fibroblast cultures also increased SA-beta-Gal expression. Fucose- and rhamnose-rich oligo- and polysaccharides (FROPs and RROPs, respectively) provided a significant protection against this AGE-induced increase of SA-beta-Gal-positive cells. It is speculated that these processes might well play an important role in skin aging.

Fragments of extracellular matrix as mediators of inflammation

Classically, the extracellular matrix (ECM) was viewed as a supporting structure for stabilizing the location of cells in tissues and for preserving the architecture of tissues. This conception has changed dramatically over the past few decades with discoveries that ECM has profound influences on the structure, viability, and functions of cells. Much of the data supporting this new paradigm has been obtained from studies of normal and pathological structural cells such as fibroblasts, smooth muscle cells, and malignant cells, as, for example, breast cancer epithelial cells. However, there has also been recognition that effects of ECM on cells extend to inflammatory cells. In this context, attention has been drawn to fragments of ECM components. In this review, we present information supporting the concept that proteolytic fragments of ECM affect multiple functions and properties of inflammatory and immune cells. Our focus is particularly upon neutrophils, monocytes, and macrophages and fragments derived from collagens, elastin, and laminins. Hyaluronan fragments, although they are not products of proteolysis, are also discussed, as they are a notable example of ECM fragments that exhibit important effects on inflammatory cells. Further, we summarize some exciting recent developments in this field as a result of mouse models in which defined ECM fragments and their receptors are clearly implicated in inflammation in vivo. Thus, this review underscores the idea that proteolysis of ECM may well have implications that go beyond modifying the structural environment of cells and tissues.