Proliferating fibroblasts at the invading tumour edge of colorectal adenocarcinomas are associated with endogenous markers of hypoxia, acidity, and oxidative stress

Tertiary Lymphoid Structures, Immune Response, and Prognostic Relevance in Non-Small Cell Lung Cancer

We assessed the presence of 'tertiary lymphoid structures' (TLS) in a series of surgically treated non-small cell lung carcinomas (NSCLC). The TLS-density in the tumor periphery (pTLS) ranged from 0 to 1.8 (median 0.45), while in inner tumor areas (iTLS) ranged from 0 to 1.0 (median 0); (p < 0.0001). High pTLS-density was linked with early stage of the disease. Glycolysis-related enzyme expression (MCT1, Hexokinase 2) was linked with high pTLS-density (p < 0.05). High pTLS and iTLS densities were linked with better postoperative prognosis (p = 0.02 and p = 0.01, respectively). Assessment of TLS is a useful prognostic marker in NSCLC.

The molecular basis of immuno-radiotherapy

PURPOSE

Radiotherapy (RT) and immunotherapy are powerful anti-tumor treatment modalities. Experimental research has demonstrated an important interplay between the cytotoxic effects of RT and the immune system. This systematic review provides an overview of the basics of anti-tumor immunity and focuses on the mechanisms underlying the interplay between RT and immune anti-tumor response that set the molecular basis of immuno-RT.

CONCLUSIONS

An 'immunity acquired equilibrium' mimicking tumor dormancy can be achieved post-irradiation treatment, with the balance shifted toward tumor eradication or regrowth when immune cells' cytotoxic effects or cancer proliferation rate prevail, respectively. RT has both immunosuppressive and immune-enhancing properties. The latter effect is also known as radio-vaccination. Its mechanisms involve up- or down-regulation of membrane molecules, such as PD-L1, HLA-class-I, CD80/86, CD47, and Fas/CD95, that play a vital role in immune checkpoint pathways and increased cytokine expression (e.g. INFα,β,γ, IL1,2, and TNFα) by cancer or immune cells. Moreover, the interactions of radiation with the tumor microenvironment (fibroblasts, tumor-infiltrating lymphocytes, monocytes, and dendritic cells are also an important component of radio-vaccination. Thus, RT may have anti-tumor vaccine properties, whose sequels can be exploited by immunotherapy agents to treat different cancer subtypes effectively.

Metabolic tricks of cancer cells

One of the characteristics of cancer cells important for tumorigenesis is their metabolic plasticity. Indeed, in various stress conditions, cancer cells can reshape their metabolic pathways to support the increased energy request due to continuous growth and rapid proliferation. Moreover, selective pressures in the tumor microenvironment, such as hypoxia, acidosis, and competition for resources, force cancer cells to adapt by complete reorganization of their metabolism. In this review, we highlight the characteristics of cancer metabolism and discuss its clinical significance, since overcoming metabolic plasticity of cancer cells is a key objective of modern cancer therapeutics and a better understanding of metabolic reprogramming may lead to the identification of possible targets for cancer therapy.

Multiomics Analysis of Spatially Distinct Stromal Cells Reveals Tumor-Induced O-Glycosylation of the CDK4-pRB Axis in Fibroblasts at the Invasive Tumor Edge

The invasive leading edge represents a potential gateway for tumor metastasis. The role of fibroblasts from the tumor edge in promoting cancer invasion and metastasis has not been comprehensively elucidated. We hypothesize that cross-talk between tumor and stromal cells within the tumor microenvironment results in activation of key biological pathways depending on their position in the tumor (edge vs. core). Here we highlight phenotypic differences between tumor-adjacent-fibroblasts (TAF) from the invasive edge and tumor core fibroblasts from the tumor core, established from human lung adenocarcinomas. A multiomics approach that includes genomics, proteomics, and O-glycoproteomics was used to characterize cross-talk between TAFs and cancer cells. These analyses showed that O-glycosylation, an essential posttranslational modification resulting from sugar metabolism, alters key biological pathways including the cyclin-dependent kinase 4 (CDK4) and phosphorylated retinoblastoma protein axis in the stroma and indirectly modulates proinvasive features of cancer cells. In summary, the O-glycoproteome represents a new consideration for important biological processes involved in tumor-stroma cross-talk and a potential avenue to improve the anticancer efficacy of CDK4 inhibitors.

SIGNIFICANCE

A multiomics analysis of spatially distinct fibroblasts establishes the importance of the stromal O-glycoproteome in tumor-stroma interactions at the leading edge and provides potential strategies to improve cancer treatment. See related commentary by De Wever, p. 537.

ITGB2-mediated metabolic switch in CAFs promotes OSCC proliferation by oxidation of NADH in mitochondrial oxidative phosphorylation system

Objectives: Integrins, the coordinator of extracellular and intracellular signaling, are often found to be aberrant in tumors and can reshape the tumor microenvironment. Although previous studies showed that integrin beta 2 (ITGB2) is important for host defense, its expression profile and role in tumors, especially in cancer associated fibroblasts (CAFs) are still unknown.

Methods: Immunofluorescence stain and fluorescence activated cell sorting were used to analyze the ITGB2 expression profile in oral squamous cell carcinoma (OSCC). RT-PCR and western blot were used to compare ITGB2 expression in normal fibroblasts (NFs) and cancer associated fibroblasts (CAFs). Clinical data and function-based experiments were used to investigate the promoting tumor growth ability of ITGB2 expressing CAFs. Enhanced glycolysis activity was identified by using bioinformatics analyses and GC/MS assays. MCT1 knockdown OSCC cell lines were constructed to explore the pro-proliferative mechanisms of ITGB2 expressing CAFs in multiple in vitro and in vivo assays.

Results: We found that CAFs exhibited significantly higher ITGB2 expression than the matched NFs. In addition, higher ITGB2 expression in CAFs was correlated with higher TNM stages and more Ki67+ tumor cells, indicating its ability to promote OSCC proliferation. Further, co-culture assay demonstrated that ITGB2-mediated lactate release in CAFs promoted OSCC cell proliferation. Mechanically, ITGB2 regulated PI3K/AKT/mTOR pathways to enhance glycolysis activity in CAFs. Accordingly, lactate derived from ITGB2-expressing CAFs was absorbed and metabolized in OSCC to generate NADH, which was then oxidized in the mitochondrial oxidative phosphorylation system (OXPHOS) to produce ATP. Notably, inhibiting the OXPHOS system with metformin delayed the proliferative capacity of OSCC cells cultured in the ITGB2-expressing CAFs medium.

Conclusions: Our study uncovered the ITGB2^high pro-tumoral CAFs that activated the PI3K/AKT/mTOR axis to promote tumor proliferation in OSCC by NADH oxidation in the mitochondrial oxidative phosphorylation system.

How Dysregulated Ion Channels and Transporters Take a Hand in Esophageal, Liver, and Colorectal Cancer

Over the last two decades, the understanding of how dysregulated ion channels and transporters are involved in carcinogenesis and tumor growth and progression, including invasiveness and metastasis, has been increasing exponentially. The present review specifies virtually all ion channels and transporters whose faulty expression or regulation contributes to esophageal, hepatocellular, and colorectal cancer. The variety reaches from Ca²⁺, K⁺, Na⁺, and Cl^- channels over divalent metal transporters, Na⁺ or Cl^- coupled Ca²⁺, HCO₃^- and H⁺ exchangers to monocarboxylate carriers and organic anion and cation transporters. In several cases, the underlying mechanisms by which these ion channels/transporters are interwoven with malignancies have been fully or at least partially unveiled. Ca²⁺, Akt/NF-κB, and Ca²⁺- or pH-dependent Wnt/β-catenin signaling emerge as cross points through which ion channels/transporters interfere with gene expression, modulate cell proliferation, trigger epithelial-to-mesenchymal transition, and promote cell motility and metastasis. Also miRs, lncRNAs, and DNA methylation represent potential links between the misexpression of genes encoding for ion channels/transporters, their malfunctioning, and cancer. The knowledge of all these molecular interactions has provided the basis for therapeutic strategies and approaches, some of which will be broached in this review.

Metabolism in the Tumor Microenvironment

From a general perspective, in the context of solid tumors, we can distinguish metabolic alterations of cancer cells from those of the stroma. These two components interact with each other and with the extracellular matrix (ECM), and these interactions can take the form of either metabolic competition or metabolic symbiosis. The aim of this chapter is to overview the canonical metabolic alterations of tumor and stroma cells and to present specific examples of metabolic competition and symbiosis. We will also discuss the complexity and plasticity of metabolism, which pose indeed a serious threat to our ability to target selective metabolic features of tumor microenvironment with drugs. Finally, we will highlight some limitations of state-of-the-art techniques used to study tumor metabolism and propose some innovative solutions to investigate the clinical relevance of metabolic alterations for patient management and treatment.

Prognostic significance of G6PD expression and localization in lung adenocarcinoma

Abnormal expressions of extracellular matrix (ECM) proteins are correlated with increased tumor progression, an advanced histologic grade, and metastasis. LCN1 cells derived from a pulmonary large cell neuroendocrine carcinoma were grown to form an Aegagropila-shaped conglomeration on a suspension culture dish (LCN1-sus). In contrast, LCN1 cells cultured in a type I collagen dish were adherent and tended to grow as spindle-shaped individual cells (LCN1-co). In this study, aiming at the discovery of predictive markers for tumor invasion, we performed protein profiling between LCN1-sus and LCN1-co cells using two-dimensional gel electrophoresis. Twenty-six protein spots with >1.2-fold quantitative differences between LCN1-sus and LCN1-co cells were detected. Among the identified proteins, we focused on and immunohistochemically investigated G6PD in lung cancer. G6PD expression was significantly associated with a higher pathological TNM stage (p = 0.0024), lymph node metastasis (p = 0.0187), poorer differentiation (p = 0.0046), pleural invasion (p = 0.0197), vascular invasion (p < 0.0001), lymphatic invasion (p = 0.0200) and poorer prognosis (p = 0.0005) in adenocarcinoma. Especially, G6PD-positive patients with overexpression at the invasive front had significantly poorer survival than those without overexpression (p = 0.0058). Moreover, multivariable analysis revealed that G6PD expression was an independent adverse-prognostic factor. These results suggest that G6PD may be a novel predictive prognostic marker for lung adenocarcinoma.

Intratumoral stromal morphometry predicts disease recurrence but not response to 5-fluorouracil-results from the QUASAR trial of colorectal cancer

AIMS

The biological importance of tumour-associated stroma is becoming increasingly apparent, but its clinical utility remains ill-defined. For stage II/Dukes B colorectal cancer (CRC), clinical biomarkers are urgently required to direct therapeutic options. We report here prognostic/predictive analyses, and molecular associations, of stromal morphometric quantification in the Quick and Simple and Reliable (QUASAR) trial of CRC.

METHODS AND RESULTS

Relative proportions of tumour epithelium (PoT) or stroma (PoS) were morphometrically quantified on digitised haematoxylin and eosin (H&E) sections derived from 1800 patients enrolled in QUASAR, which randomised 3239 (91% stage II) CRC patients between adjuvant fluorouracil/folinic acid (FUFA) chemotherapy and observation. The prognostic and predictive values of PoT/PoS measurements were determined by the use of stratified log-rank analyses. A high proportion of tumour stroma (≥50%) was associated with an increased recurrence risk: 31.3% (143/457) recurrence for ≥50% versus 21.9% (294/1343) for <50% [rate ratio (RR) 1.62; 95% confidence interval (CI) 1.30-2.02; P < 0.0001]. Of patients with stromal proportions of ≥65%, 40% (46/115) had recurrent disease within 10 years. The adverse prognostic effect of a high stromal proportion was independent of established prognostic variables, and was maintained in stage II/Dukes B patients (RR 1.62; 95% CI 1.26-2.08; P = 0.0002). KRAS mutation in the presence of a high stromal proportion augmented recurrence risk (RR 2.93; 95% CI 1.87-4.59; P = 0.0005). Stromal morphometry did not predict response to FUFA chemotherapy.

CONCLUSIONS

Simple digital morphometry applied to a single representative H&E section identifies CRC patients with a >50% higher risk of disease recurrence. This technique can reliably partition patients into subpopulations with different risks of tumour recurrence in a simple and cost-effective manner. Further prospective validation is warranted.

Increased Expression of Thymosin β4 Is Independently Correlated with Hypoxia Inducible Factor-1α (HIF-1α) and Worse Clinical Outcome in Human Colorectal Cancer

Background

Thymosin β₄ is a multi-functional hormone-like polypeptide, being involved in cell migration, angiogenesis, and tumor metastasis. This study was undertaken to clarify the clinicopathologic implications of thymosin β₄ expression in human colorectal cancers (CRCs).

Methods

We investigated tissue sections from 143 patients with CRC by immunohistochemistry. In addition, we evaluated the expression patterns and the clinico-pathological significance of thymosin β₄ expression in association with hypoxia inducible factor-1α (HIF-1α) expression in the CRC series.

Results

High expression of thymosin β₄ was significantly correlated with lymphovascular invasion, invasion depth, regional lymph node metastasis, distant metastasis, and TNM stage. Patients with high expression of thymosin β₄ showed poor recurrence-free survival (p = .001) and poor overall survival (p = .005) on multivariate analysis. We also found that thymosin β₄ and HIF-1α were overexpressed and that thymosin β₄ expression increased in parallel with HIF-1α expression in CRC.

Conclusions

A high expression level of thymosin β₄ indicates poor clinical outcomes and may be a useful prognostic factor in CRC. Thymosin β₄ is functionally related with HIF-1α and may be a potentially valuable biomarker and possible therapeutic target for CRC.

HIF-1α expression and high microvessel density are characteristic features in serrated colorectal cancer

Serrated colorectal adenocarcinoma (SAC) is a morphologically distinct subtype of colorectal cancer (CRC), in which increased HIF-1α mRNA expression and HIF-1α protein stabilization are typical features. Here we aimed to further elucidate HIF-1α protein expression in serrated and non-serrated colorectal carcinomas (CRCs) and their precursor lesions and its association with vascular endothelial growth factor (VEGF) and microvascular density (MVD). HIF-1α and VEGF expressions were determined immunohistochemically in 134 serrated polyps (SPs), 104 non-serrated adenomas (NSAs), 81 SACs, and 74 matched conventional adenocarcinomas (CCs) and were correlated with morphology, clinicopathological features, and MVD. In premalignant lesions, both HIF-1α and VEGF were expressed in the vast majority of SPs and NSAs. In CRCs, HIF-1α protein was also present in 77.8 % of SACs, while only 20.3 % of CCs were HIF-1α proficient. MVD was significantly higher in SACs, but the serrated morphology was the only significant predictor of MVD in CRC in multivariate analyses. HIF-1α protein is often stabilized in well-vascularized SACs, suggesting hypoxia-independent stabilization of HIF-1α. Moreover, HIF-1α stabilization did not associate with oncogenic activation of BRAF or KRAS or Von Hippel-Lindau (VHL) mutation. Prevalent HIF-1α expression in SAC and its precursors support the importance of HIF-1α-mediated pathways for the serrated route of colorectal carcinogenesis.

Matrix Rigidity Mediates TGFβ1-Induced Epithelial-Myofibroblast Transition by Controlling Cytoskeletal Organization and MRTF-A Localization

Myofibroblasts mediate normal wound healing and upon chronic activation can contribute to the development of pathological conditions including organ fibrosis and cancer. Myofibroblasts can develop from epithelial cells through an epithelial-mesenchymal transition (EMT) during which epithelial cells exhibit drastic morphological changes and upregulate cytoskeletal associated proteins that enable exertion of large contractile forces and remodeling of the surrounding microenvironment. Increased matrix rigidity is a hallmark of fibrosis and tumor progression and mechanical tension has been identified as a regulator of EMT; however, the mechanisms governing the mechanical regulation of EMT are not completely understood. Here, we find that matrix rigidity regulates transforming growth factor (TGF)-β1-induced EMT, with rigid substrata enabling increased myofibroblast marker expression, cell morphology changes, and cytoskeletal reorganization while soft matrices block these changes. Furthermore, we find that matrix rigidity controls the subcellular localization of myocardin related transcription factor (MRTF)-A, a regulator of cytoskeletal protein expression that contributes to the acquisition of myogenic features during EMT. Results from these studies provide insight into how biophysical cues contribute to myofibroblast development from epithelial cells and may suggest ways to enhance wound healing or to engineer therapeutic solutions for fibrosis and cancer.

Cancer-associated fibroblasts connect metastasis-promoting communication in colorectal cancer

Colorectal cancer (CRC) progression and eventually metastasis is directed in many aspects by a circuitous ecosystem consisting of an extracellular matrix scaffold populated by cancer-associated fibroblasts (CAFs), endothelial cells, and diverse immune cells. CAFs are recruited from local tissue-resident fibroblasts or pericryptal fibroblasts and distant fibroblast precursors. CAFs are highly abundant in CRC. In this review, we apply the metastasis-promoting communication of colorectal CAFs to 10 cancer hallmarks described by Hanahan and Weinberg. CAFs influence innate and adaptive tumor immune responses. Using datasets from previously published work, we re-explore the potential messages implicated in this process. Fibroblasts present in metastasis (metastasis-associated fibroblasts) from CRC may have other characteristics and functional roles than CAFs in the primary tumor. Since CAFs connect metastasis-promoting communication, CAF markers are potential prognostic biomarkers. CAFs and their products are possible targets for novel therapeutic strategies.

Biomechanics of TGFβ-induced epithelial-mesenchymal transition: implications for fibrosis and cancer

Fibrosis, a disease that results in loss of organ function, contributes to a significant number of deaths worldwide and sustained fibrotic activation has been suggested to increase the risk of developing cancer in a variety of tissues. Fibrogenesis and tumor progression are regulated in part through the activation and activity of myofibroblasts. Increasing evidence links myofibroblasts found within fibrotic lesions and the tumor microenvironment to a process termed epithelial-mesenchymal transition (EMT), a phenotypic change in which epithelial cells acquire mesenchymal characteristics. EMT can be stimulated by soluble signals, including transforming growth factor (TGF)-β, and recent studies have identified a role for mechanical cues in directing EMT. In this review, we describe the role that EMT plays in fibrogenesis and in the progression of cancer, with particular emphasis placed on biophysical signaling mechanisms that control the EMT program. We further describe specific TGFβ-induced intracellular signaling cascades that are affected by cell- and tissue-level mechanics. Finally, we highlight the implications of mechanical induction of EMT on the development of treatments and targeted intervention strategies for fibrosis and cancer.

Metabolic symbiosis in cancer: refocusing the Warburg lens

Using relatively primitive tools in the 1920s, Otto Warburg demonstrated that tumor cells show an increased dependence on glycolysis to meet their energy needs, regardless of whether they were well-oxygenated or not. High rates of glucose uptake, fueling glycolysis, are now used clinically to identify cancer cells. However, the Warburg effect does not account for the metabolic diversity that has been observed amongst cancer cells nor the influences that might direct such diversity. Modern tools have shown that the oncogenes, variable hypoxia levels, and the utilization of different carbon sources affect tumor evolution. These influences may produce metabolic symbiosis, in which lactate from a hypoxic, glycolytic tumor cell population fuels ATP production in the oxygenated region of a tumor. Lactate, once considered a waste product of glycolysis, is an important metabolite for oxidative phosphorylation in many tissues. While much is known about how muscle and the brain use lactate in oxidative phosphorylation, the contribution of lactate in tumor bioenergetics is less defined. A refocused perspective of cancer metabolism that recognizes metabolic diversity within a tumor offers novel therapeutic targets by which cancer cells may be starved from their fuel sources, and thereby become more sensitive to traditional cancer treatments.

Hereditary ovarian cancer and two-compartment tumor metabolism: epithelial loss of BRCA1 induces hydrogen peroxide production, driving oxidative stress and NFκB activation in the tumor stroma

Mutations in the BRCA1 tumor suppressor gene are commonly found in hereditary ovarian cancers. Here, we used a co-culture approach to study the metabolic effects of BRCA1-null ovarian cancer cells on adjacent tumor-associated stromal fibroblasts. Our results directly show that BRCA1-null ovarian cancer cells produce large amounts of hydrogen peroxide, which can be abolished either by administration of simple antioxidants (N-acetyl-cysteine; NAC) or by replacement of the BRCA1 gene. Thus, the BRCA1 gene normally suppresses tumor growth by functioning as an antioxidant. Importantly, hydrogen peroxide produced by BRCA1-null ovarian cancer cells induces oxidative stress and catabolic processes in adjacent stromal fibroblasts, such as autophagy, mitophagy and glycolysis, via stromal NFκB activation. Catabolism in stromal fibroblasts was also accompanied by the upregulation of MCT4 and a loss of Cav-1 expression, which are established markers of a lethal tumor microenvironment. In summary, loss of the BRCA1 tumor suppressor gene induces hydrogen peroxide production, which then leads to metabolic reprogramming of the tumor stroma, driving stromal-epithelial metabolic coupling. Our results suggest that new cancer prevention trials with antioxidants are clearly warranted in patients that harbor hereditary/familial BRCA1 mutations.

Expression of endothelial cell-specific molecule-1 regulated by hypoxia inducible factor-1α in human colon carcinoma: impact of ESM-1 on prognosis and its correlation with clinicopathological features

Based on a previous finding that endothelial cell-specific molecule-1 (ESM-1) is a potential serum marker for colorectal cancer (CRC), the aim of this study was to clarify the clinicopathological significance of ESM-1 expression in CRC, and to explore the correlation between ESM-1 and HIF-1α in the tumorigenesis of CRC related to hypoxic conditions. ESM-1 mRNA expression was examined in CRC and corresponding normal mucosal tissues by reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time RT-PCR. This experiment confirmed that ESM-1 levels were high in CRC. We screened the tissue samples of 143 CRC patients. By immunohistochemistry, we determined that the ESM-1 immunoreactivity was significantly correlated with the tumor size, depth of invasion, nodal status, distant metastasis and Dukes' stage, and was an independent prognostic factor for disease recurrence and worse survival outcome (P=0.001). The modulation of ESM-1 under hypoxia was investigated, and it was confirmed that ESM-1 expression was induced by HIF1-α and significantly attenuated by small interfering RNA (siRNA) targeting HIF-1α in CRC cells. These results showed that ESM-1 is significantly overexpressed, which is regulated by HIF-1α in CRC patients, and can be used as a potential biomarker and a therapeutic target for CRC.

Targeting carcinoma-associated fibroblasts within the tumor stroma with a fibroblast activation protein-activated prodrug

BACKGROUND

Fibroblasts undergo a morphological transformation to a reactive phenotype in the tumor microenvironment characterized by the expression of proteins such as fibroblast activation protein (FAP), a post-prolyl endopeptidase with expression largely restricted to carcinoma-associated fibroblasts. Thapsigargin (TG) is a highly toxic natural plant product that triggers a rise in intracellular calcium levels and apoptosis. FAP is therefore a provocative target for the activation of prodrugs consisting of a FAP-specific peptide coupled to a potent cytotoxic analog of TG.

METHODS

The efficacy of FAP-activated peptidyl-TG prodrugs was tested in vitro in cell proliferation assays and effects on intracellular calcium in human cancer cell lines. The effects of FAP-activated prodrugs on tumor growth and host toxicity were tested in Balb-C nude MCF-7 and LNCaP xenograft mice (n = 9-11 per group). P values were calculated using permutation tests based on 50 000 permutations. Mixed effects models were used to account for correlations among replicate measures. All statistical tests were two-sided.

RESULTS

FAP-activated prodrugs killed human cancer cells at low nanomolar concentrations (MCF-7 cells: IC(50) = 3.5 nM). Amino acid-12ADT analogs from FAP-cleaved prodrugs, but not uncleaved prodrugs, produced a rapid rise in intracellular calcium within minutes of exposure. Immunohistochemical analysis of xenografts exposed to FAP-prodrugs documented stromal-selective cell death of fibroblasts, pericytes, and endothelial cells of sufficient magnitude to inhibit growth of MCF-7 and LNCaP xenografts with minimal systemic toxicity, whereas non-FAP cleavable prodrugs were inactive. MCF-7 and LNCaP xenografts treated with a FAP-activated prodrug had maximal treated-to-control tumor volume ratios of 0.36 (treated: mean = 0.206 mm(3), 95% CI = 0.068 to 0.344 mm(3); control: mean = 0.580 mm(3), 95% CI = 0.267 to 0.893 mm(3)) and 0.24 (treated: mean = 0.131 mm(3), 95% CI = 0.09 to 0.180 mm(3); control: mean = 0.543 mm(3), 95% CI = 0.173 to 0.913 mm(3)), respectively, on day 21 after therapy.

CONCLUSIONS

This study validates the proteolytic activity of FAP as a target for the activation of a systemically delivered cytotoxic prodrug and demonstrates that targeted killing of cells within the stromal compartment of the tumor microenvironment can produce a therapeutic response.

Radiation damage and radioprotectants: new concepts in the era of molecular medicine

Exposure to ionising radiation results in mutagenesis and cell death, and the clinical manifestations depend on the dose and the involved body area. Reducing carcinogenesis in patients treated with radiotherapy, exposed to diagnostic radiation or who are in certain professional groups is mandatory. The prevention or treatment of early and late radiotherapy effects would improve quality of life and increase cancer curability by intensifying therapies. Experimental and clinical data have given rise to new concepts and a large pool of chemical and molecular agents that could be effective in the protection and treatment of radiation damage. To date, amifostine is the only drug recommended as an effective radioprotectant. This review identifies five distinct types of radiation damage (I, cellular depletion; II, reactive gene activation; III, tissue disorganisation; IV, stochastic effects; V, bystander effects) and classifies the radioprotective agents into five relevant categories (A, protectants against all types of radiation effects; B, death pathway modulators; C, blockers of inflammation, chemotaxis and autocrine/paracrine pathways; D, antimutagenic keepers of genomic integrity; E, agents that block bystander effects). The necessity of establishing and funding central committees that guide systematic clinical research into evaluating the novel agents revealed in the era of molecular medicine is stressed.

Caveolin-1 and cancer metabolism in the tumor microenvironment: markers, models, and mechanisms

Caveolins are a family of membrane-bound scaffolding proteins that compartmentalize and negatively regulate signal transduction. Recent studies have implicated a loss of caveolin-1 (Cav-1) expression in the pathogenesis of human cancers. Loss of Cav-1 expression in cancer-associated fibroblasts results in an activated tumor microenvironment, thereby driving early tumor recurrence, metastasis, and poor clinical outcome in breast and prostate cancers. We describe various paracrine signaling mechanism(s) by which the loss of stromal Cav-1 promotes tumor progression, including fibrosis, extracellular matrix remodeling, and the metabolic/catabolic reprogramming of cancer-associated fibroblast, to fuel the growth of adjacent tumor cells. It appears that oxidative stress is the root cause of initiation of the loss of stromal Cav-1 via autophagy, which provides further impetus for the use of antioxidants in anticancer therapy. Finally, we discuss the functional role of Cav-1 in epithelial cancer cells.

Overexpression of ZEB2 at the invasion front of colorectal cancer is an independent prognostic marker and regulates tumor invasion in vitro

PURPOSE

Epithelial-to-mesenchymal transition (EMT) plays a pivotal role in tumor invasion and dissemination. EMT occurs predominantly at the tumor edge where it is induced by cytokines, the extracellular matrix environment, or hypoxia. In the tumor cell, it is further mediated by several transcription factors and microRNAs. The aim of this study was to explore the expression of EMT-associated genes at the invasive front in colorectal cancer and to evaluate their prognostic significance.

EXPERIMENTAL DESIGN

We evaluated the expression of 13 EMT-associated genes at the invasion front of 30 colorectal liver metastases by quantitative real-time PCR. Immunostaining against zinc finger E-box-binding homeobox 2 (ZEB2) was carried out on 175 primary colorectal cancer specimens and 30 colorectal liver metastases and correlated to clinical and histopathologic data. DLD-1 cells were transfected with siRNA and subjected to migration and invasion assays.

RESULTS

Gene expression analysis and immunohistochemistry showed an upregulation of ZEB2 at the invasion front in primary colorectal cancer and liver metastases. Overexpression of ZEB2 at the invasion front correlated significantly with tumor stage in primary colorectal cancer. Moreover, univariate and multivariate analysis revealed overexpression of ZEB2 at the invasion front as an independent prognostic marker for cancer-specific survival. Downregulation of ZEB2 by siRNA decreased the migration and invasion capacity of DLD-1 cells in vitro.

CONCLUSIONS

Overexpression of ZEB2 at the invasion front correlates with tumor progression and predicts cancer-specific survival in primary colorectal cancer. Therefore, ZEB2 may be interesting as biomarker and potential target for treatment of colorectal cancer.

LC3A-positive "stone-like" structures in cutaneous squamous cell carcinomas

This study was set to investigate the relation between autophagic activity and the aggressiveness of cutaneous squamous cell carcinomas (SCC), as indicated by tumor thickness and proliferative activity. The anti-LC3A antibody, recognizing both the soluble and the autophagosome-bound forms of the protein, and a standard immunohistochemical technique were applied to 75 cutaneous SCC of variable tumor thickness. The study was complemented by staining for MIB1. Three patterns of LC3A reactivity were recognized: diffuse cytoplasmic, cytoplasmic/perinuclear, and "stone-like" structures (SLS), that is, large, rounded, densely stained amorphous material, 5 μm on average, enclosed within cytoplasmic vacuoles. Higher numbers of SLS were counted in >6-mm-thick SCC compared with the intermediate-thickness tumors (2.1-6 mm) and the <2-mm-thick tumors; the mean recorded values, being 8.8, 4.55, and 1.55, respectively, were statistically significant. The diffuse cytoplasmic staining showed a nearly inverse trend, whereas the perinuclear pattern, expressed in <10% of the total, was not evaluated. With regard to MIB1 proliferation index, this increased with tumor thickness and, in linear regression analysis, was directly linked with SLS counts and inversely with the cytoplasmic pattern. These data suggest that autophagic activity in SCC, when expressed as high LC3A/SLS counts, can be regarded as an indicator of tumor aggressiveness.

Cysteine/cystine redox signaling in cardiovascular disease

Extracellular thiol/disulfide redox environments are highly regulated in healthy individuals. The major thiol/disulfide redox couple in human plasma is cysteine (Cys) and its disulfide form, cystine (CySS). Oxidation of this redox couple, measured as a more positive steady-state redox potential (E(h)), is associated with risk factors for cardiovascular disease (CVD), including aging, smoking, obesity, and alcohol abuse. Rodent and vascular cell studies show that the extracellular redox state of Cys/CySS (E(h)CySS) can play a vital role in controlling CVD through proinflammatory signaling. This inflammatory signaling is regulated by cell-surface protein redox state and involves mitochondrial oxidation, nuclear factor-κB activation, and elevated expression of genes for monocyte recruitment to endothelial cells. Gene array and proteomics studies reveal the global nature of redox effects, and different cell types, e.g., endothelial cells, monocytes, fibroblasts, and epithelial cells, show cell-specific redox responses with different phenotypic traits, e.g., proliferation and apoptosis, which can contribute to CVD. The critical nature of the proinflammatory redox signaling and cell biology associated with E(h)CySS supports the use of plasma levels of Cys, CySS, and E(h)CySS as key indicators of vascular health. Plasma redox-state-based pharmacologic interventions to control or improve E(h)CySS may be effective in preventing CVD onset or progression.

The impact of expressions of CD97 and its ligand CD55 at the invasion front on prognosis of rectal adenocarcinoma

BACKGROUND

Various evidence show that CD97 plays an important role in tumor differentiation, migration, invasiveness, and metastasis by binding its cellular ligand CD55. CD55 is a complement regulatory protein expressed by cells to protect them from bystander attack by complement, and it has been shown to be an indicator of poor prognostic in several cancers.

METHODS

CD97 and CD55 stains were detected in tumor tissues from 71 cases of rectal adenocarcinomas and their corresponding normal colorectal tissues by immunohistochemistry.

RESULTS

The expressions of CD97 and CD55 in rectal tumor tissues were significantly higher than those in normal colorectal tissues (P < 0.05, both). The patients with recurrence and/or metastasis had significantly higher expressions of CD97 at tumor cells and CD55 at stroma (67.8% [21/31] and 63.6% [21/33]) at the invasion front than those patients without recurrence and/or metastasis (25.0% [10/40] and 26.3% [10/38]). The expression of CD97 at tumor cell at the invasion front showed modest correlation with that of CD55 in the stroma at the invasion front(r = 0.392, P < 0.01). Univariate analysis revealed that lymph node metastasis (P = 0.001), stages II-IV (P = 0.026), and strong CD97 expression at tumor invasion front (P = 0.002) were shown to have a significant adverse impact on the postoperative survival rate. Moreover, lymph node metastasis (P = 0.037) and strong CD97 expression (P = 0.015) were associated with poor survival in a multivariate analysis.

CONCLUSIONS

Elevated expression of CD97 and its ligand CD55 at the invasion front correlate with tumor recurrence and metastasis, and CD95 may be a poor prognostic factor for rectal adenocarcinoma.

The (in) auspicious role of mesenchymal stromal cells in cancer: be it friend or foe

Recent progress in the research of mesenchymal stromal cells/multipotent stromal cells (MSC) has revealed numerous beneficial innate characteristics, suggesting potential value in an array of cellular therapies. MSC are easily isolated from bone marrow (BM), fat and other tissues, and are readily propagated in vitro. Transplanted/injected MSC have been shown to migrate to a variety of organs and tissues; however, sites of inflammation and pathology elicit enhanced MSC homing for tissue remodeling and repair. Tumors utilize many of the same inflammatory mediators uncovered in wound healing and likewise provide a site for preferential MSC homing. Although incorporation into the tumor microenvironment is apparent, the role of recruited MSC in the tumor microenvironment remains unclear. Some published studies have shown enhancement of tumor growth and development, perhaps through immunomodulatory and pro-angiogenic properties, while others have shown no apparent effect or have demonstrated inhibition of tumor growth and extended survival. This controversy remains at the forefront as clinical applications of MSC commence in anti-tumor therapies as well as as adjuncts to stem cell transplantation and in ameliorating graft-versus-host disease. Careful analysis of past studies and thoughtful design of future experiments will help to resolve the discrepancies in the field and lead to clinical utility of MSC in disease treatment. This review highlights the current theories of the role of MSC in tumors and explores current controversies.

Expression of hepatocyte growth factor activator inhibitor type 1 on the epithelial cell surface is regulated by hypoxic and oxidative stresses

Hepatocyte growth factor activator inhibitor type 1 (HAI-1)/spint-1 is a membrane-bound protease inhibitor that is thought to regulate the activities of hepatocyte growth factor activator, matriptase, hepsin, and prostasin. In this study, we show that the membrane form of HAI-1 was significantly upregulated immunohistochemically in epithelial cells under adverse conditions including tissue injury, necroinflammatory reactions, and invasion of carcinomas. To analyze the mechanism underlying these in vivo observations, we examined the effects of hypoxia and oxidative stress on HAI-1 expression in vitro, using three human cell lines, HLC-1, WiDr, and HeLa. Hypoxic condition significantly enhanced the expression of HAI-1 in these cells. Oxidative stress also enhanced HAI-1 expression. Promoter analyses of the human HAI-1/spint-1 gene revealed overlapping binding site for Egr-1-3 and Sp1 near the transcription start site as the key domain for HAI-1/spint-1 transcription. This site was also critical in both hypoxic- and oxidative stress-induced HAI-1 upregulation. In fact, in vivo immunohistochemical studies indicated that areas with HAI-1 upregulation tended to express markers associated with hypoxia and oxidative stress. These observations suggest that the tissue microenvironment regulates the cell surface expression of HAI-1, and thereby may regulate proteolysis and processing of bioactive molecules on the cellular surface.

Tumour-stroma interactions in colorectal cancer: converging on beta-catenin activation and cancer stemness

Sporadic cases of colorectal cancer are primarily initiated by gene mutations in members of the canonical Wnt pathway, ultimately resulting in β-catenin stabilisation. Nevertheless, cells displaying nuclear β-catenin accumulation are nonrandomly distributed throughout the tumour mass and preferentially localise along the invasive front where parenchymal cells are in direct contact with the stromal microenvironment. Here, we discuss the putative role played by stromal cell types in regulating β-catenin intracellular accumulation in a paracrine fashion. As such, the tumour microenvironment is likely to maintain the cancer stem cell phenotype in a subset of cells, thus mediating invasion and metastasis.

Epithelial and mesenchymal tumor compartments exhibit in vivo complementary patterns of vascular perfusion and glucose metabolism

Glucose transport and consumption are increased in tumors, and this is considered a diagnostic index of malignancy. However, there is recent evidence that carcinoma-associated stromal cells are capable of aerobic metabolism with low glucose consumption, at least partly because of their efficient vascular supply. In the present study, using dynamic contrast-enhanced magnetic resonance imaging and [F-18]fluorodeoxyglucose (FDG) positron emission tomography (PET), we mapped in vivo the vascular supply and glucose metabolism in syngeneic experimental models of carcinoma and mesenchymal tumor. We found that in both tumor histotypes, regions with high vascular perfusion exhibited a significantly lower FDG uptake. This reciprocity was more conspicuous in carcinomas than in mesenchymal tumors, and regions with a high-vascular/low-FDG uptake pattern roughly overlapped with a stromal capsule and intratumoral large connectival septa. Accordingly, mesenchymal tumors exhibited a higher vascular perfusion and a lower FDG uptake than carcinomas. Thus, we provide in vivo evidence of vascular/metabolic reciprocity between epithelial and mesenchymal histotypes in tumors, suggesting a new intriguing aspect of epithelial-stromal interaction. Our results suggests that FDG-PET-based clinical analysis can underestimate the malignity or tumor extension of carcinomas exhibiting any trait of "mesenchymalization" such as desmoplasia or epithelial-mesenchymal transition.

Mesenchymal stem cells in cancer: tumor-associated fibroblasts and cell-based delivery vehicles

Recent evidence suggests that mesenchymal stem cells (MSC) selectively home to tumors, where they contribute to the formation of tumor-associated stroma. This effect can be opposed by genetically modifying MSC to produce high levels of anti-cancer agents that blunt tumor growth kinetics and inhibit the growth of tumors in situ. In this review article, we describe the biological properties of MSC within the tumor microenvironment and discuss the potential use of MSC and other bone marrow-derived cell populations as delivery vehicles for antitumor proteins.

Activated VEGFR2/KDR pathway in tumour cells and tumour associated vessels of colorectal cancer

BACKGROUND

Vascular endothelial cell growth factor (VEGF) acts by phosphorylating specific tyrosine kinase receptors on endothelial cell membrane promoting angiogenesis. The study of the activation status of VEGF receptors in human malignancies has recently become feasible by means of specific monoclonal antibodies recognising the phosphorylated form of these receptors.

MATERIALS AND METHODS

In the current study, we investigate the expression of the phosphorylated VEGFR2/KDR receptor in normal colon and colorectal adenocarcinomas in parallel with histopathological parameters, prognosis and the expression of the 'hypoxia inducible factor' HIF1alpha.

RESULTS

pVEGFR2/KDR was weakly expressed in the normal colon, but it was expressed strongly in the cytoplasm and nuclei of cancer cells and in the tumour associated vasculature, mainly at the invading tumour edge. pVEGFR2/KDR expression in cancer cells was significantly associated with a tumour diameter > 6 cm (P = 0.04), poor histological differentiation (P = 0.004) and with high CEF1alpha expression (P = 0.05). High pVEGFR2/KDR expressing vascular density was significantly related with a high VEGF and HIF1alpha expression in cancer cells (P = 0.02 and 0.03, respectively). This was also related significantly to high pVEGFR2/KDR expression in cancer cells. In multivariate analysis, the most significant predictors for death were lympho-vascular invasion (P < 0.001) followed by VEGF (P = 0.014), node status (P = 0.015), standard vascular density (P = 0.022) and necrosis (P = 0.032).

CONCLUSIONS

pVEGFR2 receptors are largely expressed in colon cancer cells and intratumoural vasculature. As VEGF targeting agents enter the clinical practice, the role of monoclonal antibodies recognising the phosphorylated form of VEGF receptors as predictors of response to targeted therapies should be sought in clinicopathological trials.

The evolving concept of tumor microenvironments

The role of the microenvironment in cancer development is being increasingly appreciated. This paper will review data that highlight an emerging distinction between two different entities: the microenvironment that altered/preneoplastic/neoplastic cells find in the tissue where they reside, and the peculiar microenvironment inside the focal lesion (tumor) that these cells contribute to create. While alteration in the tissue environment can contribute to the selective clonal expansion of altered cells to form focal proliferative lesions, the atypical, non-integrated growth pattern that defines such focal lesions leads to the appearance of what is correctly referred to as the tumor microenvironment. The latter represents a new and unique biological milieu, characterized by hypoxia, acidosis and other biochemical and metabolic alterations, including genetic instability, that can set the stage for tumor progression to occur. Thus, the two microenvironments act in sequence and play complementary roles in the development of overt neoplasia. This distinction has important implications for the understanding of disease pathogenesis and for the management of preneoplastic/neoplastic lesions at various stages of cancer development.

Cumulative expression of HIF-1-alpha, Bax, Bcl-xL and P53 in human colorectal cancer

AIMS AND METHODS

Hypoxia-inducible factor (HIF-1) which contains oxygen regulated HIF-1alpha subunit maintains cytoprotective defence against hypoxic injury by induction of numerous genes. However, apoptotic regulators such as Bcl-xL, Bax and P53 have not been associated with HIF-1 dependent regulation in immunohistochemical evaluation of human colorectal cancer tumours so far. Thus, we visualised these proteins immunohistochemically and using Spearman's test compared for the first time their expression in regard to different clinicopathological traits in 123 (113 for P53 evaluation) human colorectal cancers.

RESULTS

HIF-1alpha correlated with Bcl-xL or Bax in all patients and particularly in node negative and node positive cancers, deeper intramural tumours (pT3+pT4) and adenocarcinomas. There was no significance in a small group of tumours with lesser extent through intestinal walls (pT1+pT2). In addition HIF-1alpha associated with Bcl-xL in mucinous cancers. Moreover, HIF-1alpha correlated with Bcl-xL or Bax in moderately (G2) and poorly differentiated (G3) cancers, rectal and colonic tumours and in different sex and age groups. P53 correlated only with Bax exclusively in younger patients.

CONCLUSIONS

HIF-1alpha may influence expression of Bax or Bcl-xL, at least indirectly, as correlations between HIF-1alpha and Bax or Bcl-xL occur constantly.

Hypoxia influences the cellular cross-talk of human dermal fibroblasts. A proteomic approach

The ability of cells to respond to changes in oxygen availability is critical for many physiological and pathological processes (i.e. development, aging, wound healing, hypertension, cancer). Changes in the protein profile of normal human dermal fibroblasts were investigated in vitro after 96 h in 5% CO(2) and 21% O(2) (pO(2) = 140 mm Hg) or 2% O(2) (pO(2) = 14 mm Hg), these parameters representing a mild chronic hypoxic exposure which fibroblasts may undergo in vivo. The proliferation rate and the protein content were not significantly modified by hypoxia, whereas proteome analysis demonstrated changes in the expression of 56 proteins. Protein identification was performed by mass spectrometry. Data demonstrate that human fibroblasts respond to mild hypoxia increasing the expression of hypoxia inducible factor (HIF1a) and of the 150-kDa oxygen-regulated protein. Other differentially expressed proteins appeared to be related to stress response, transcriptional control, metabolism, cytoskeleton, matrix remodelling and angiogenesis. Furthermore, some of them, like galectin 1, 40S ribosomal protein SA, N-myc-downstream regulated gene-1 protein, that have been described in the literature as possible cancer markers, significantly changed their expression also in normal hypoxic fibroblasts. Interestingly, a bovine fetuin was also identified that appeared significantly less internalised by hypoxic fibroblasts. In conclusion, results indicate that human dermal fibroblasts respond to an in vitro mild chronic hypoxic exposure by modifying a number of multifunctional proteins. Furthermore, data highlight the importance of stromal cells in modulating the intercellular cross-talk occurring in physiological and in pathologic conditions.

The invasive front in endometrial carcinoma: higher proliferation and associated derailment of cell cycle regulators

The aim of the study was to explore whether expression of proliferation and hypoxia-related proteins differs in the central parts and the invasive front in endometrial carcinomas. Proliferation-associated proteins Ki67 and cyclin A; cell cycle regulators p16, p21, p53, cyclin D1, cyclin E, and cdk2; and hypoxia-inducible factor 1alpha and its downstream factors glucose transporter 1, carbonic anhydrase IX, and vascular endothelial growth factor were immunohistochemically stained in paraffin-embedded specimens from endometrioid (n = 33), mucinous (n = 1), and serous (n = 5) endometrial carcinomas. The percentages of positive cells at the invasive front and central tumor parts were scored and compared. Ki67 (P < .001), cyclin E (P = .018), p16 (P = .003), and cdk2 (.001) were expressed higher at the invasive front than centrally (Wilcoxon signed ranks test). Higher expression of these antigens at the invasive front was seen in 31 of 38 cases for Ki67, in 16 of 39 cases for cyclin E, in 15 of 39 cases for cdk2, and in 11 of 39 cases for p16. The other cell cycle proteins and the hypoxia-related factors did not show significant differences in expression between the central parts and the invasive front. Endometrial carcinomas clearly show an invasive front that is characterized by higher proliferation and progressive derailment of the cell cycle regulators cyclin E, p16, and cdk2, but not by an increased hypoxic response.

The participation of mesenchymal stem cells in tumor stroma formation and their application as targeted-gene delivery vehicles

Recent evidence suggests that mesenchymal stem cells (MSC) selectively proliferate to tumors and contribute to the formation of tumor-associated stroma. The biological rationale for tumor recruitment of MSC remains unclear but may represent an effort of the host to blunt tumor cell growth and improve survival. There is mounting experimental evidence that normal stromal cells can revert malignant cell behavior, and separate studies have demonstrated that stromal cells can enhance tumor progression after acquisition of tumor-like genetic lesions. Together, these observations support the rationale for modifying normal MSC to deliver therapeutic proteins directly into the tumor microenvironment. Modified MSC can produce high concentrations of antitumor proteins directly within the Tumor mass, which have been shown to blunt tumor growth kinetics in experimental animal model systems. In this chapter we will address the biological properties of MSC within the tumor microenvironment and discuss the potential use of MSC and other bone marrow-derived cell populations as delivery vehicles for antitumor proteins.

Angiogenesis in colorectal cancer: prognostic and therapeutic implications

Angiogenesis is important for tumor growth and metastasis. This account reviews the clinicopathological studies conducted in the field of angiogenesis in colorectal cancer, the methods of assessing vascular-related characteristics in tissue sections and provides a background for the usefulness of antiangiogenic policies along with chemotherapy and radiotherapy. Highly angiogenic colorectal tumors are associated with aggressive histopathological features and poor patients' survival. Similarly, factors stimulating angiogenesis, such as vascular endothelial growth factor (VEGF), thymidine phosphorylase (TP), and others, are commonly related to increased vascular density (VD) and, therefore, to an unfavorable clinical course. Anti-VEGF agents have improved prognosis in patients with metastatic colorectal cancer, when added to standard chemotherapy. It is expected that, in addition to adjuvant chemotherapy and radiotherapy, agents blocking the stimulatory effect of VEGF on endothelial cells would prove beneficial to the patient.

Lactate dehydrogenase 5 expression in operable colorectal cancer: strong association with survival and activated vascular endothelial growth factor pathway--a report of the Tumour Angiogenesis Research Group

PURPOSE

Lactate dehydrogenase 5 (LDH-5) regulates, under hypoxic conditions, the anaerobic transformation of pyruvate to lactate for energy acquisition. Several studies have shown that serum LDH may be an ominous prognostic marker in malignant tumors. The clinical significance of tissue LDH-5, however, remains largely unexplored.

PATIENTS AND METHODS

We investigated the immunohistochemical expression of LDH-5 in a series of 128 stage II/III colorectal adenocarcinomas treated with surgery alone. In addition, markers of tumor hypoxia (hypoxia-inducible factor 1 alpha [HIF1alpha]), angiogenesis (vascular endothelial growth factor [VEGF] and phosporylated kinase domain receptor [pKDR]/flk-1 receptor) and the tumor vascular density (CD31 positive standard vascular density [sVD] and pKDR positive activated vascular density [aVD]) were assessed.

RESULTS

The expression of LDH-5, together with that of HIF1alpha and pKDR, was both nuclear and cytoplasmic. Assessment, with minimal interobserver variability, was achieved using a previously described scoring system. LDH-5 was significantly associated with HIF1alpha (P = .01), aVD (P = .001) and, particularly, with pKDR expression in cancer cells (P = .0001). Tissue LDH-5 expression was linked with elevated serum LDH levels, but serum levels failed to reflect tissue expression in 71% of LDH-5 positive cases. In univariate analysis tissue LDH-5 was associated with poor survival (P = .0003, HR 15.1), whereas in multivariate analysis this isoenzyme was the strongest independent prognostic factor (P = .0009). VEGF, pKDR, aVD, sVD and vascular invasion were all significantly related to unfavorable prognosis.

CONCLUSION

The immunohistochemical assessment of tissue LDH-5 and pKDR provides important prognostic information in operable colorectal cancer. The strong association between LDH-5 and pKDR expression would justify their use as surrogate markers to screen patients for tyrosine kinase inhibitor therapy.

Metallothionein-1 and -2 expression in cadmium- or arsenic-derived human malignant urothelial cells and tumor heterotransplants and as a prognostic indicator in human bladder cancer

The goal of this study was to determine if the expression of the metallothionein (MT)-1/2 proteins might serve as a biomarker for the development of bladder cancer. A retrospective analysis of MT-1/2 staining was performed on 343 tissue sections from patients referred for the diagnosis of bladder cancer. The specimens were subdivided into six categories: benign, dysplastic, low-grade cancer, high-grade cancer with no evidence of invasion, high-grade cancer with evidence of invasion, and carcinoma in situ. There was no expression of MT-1/2 in benign lesions and low-grade cancers, a low incidence of expression in dysplastic lesions and high-grade cancers with no evidence of muscle invasion, and a significantly increased incidence of MT-1/2 in high-grade cancers that had invaded the underlying matrix. The expression of MT-1/2 varied in intensity from sample to sample and was focal in its expression. It was concluded from these findings that MT-1/2 may be a prognostic marker for cancers that are progressing to invade the underlying stroma of the bladder wall. The expression of MT-1/2 was also determined in a cell culture model of human urothelium that had been malignantly transformed by Cd2+ and As3+ and shown to be capable of tumor formation in nude mice. It was demonstrated that the expression of MT-1/2 in the tumor heterotransplants was similar to the pattern found in archival specimens of high-grade bladder cancers. The MT-1/2 staining in the heterotransplants was focal in pattern, varied in intensity, and highest in the less differentiated cells of the tumor. These findings indicate that the cell culture model may serve to help define the role of MT-1/2 expression in bladder cancer invasion.

Comparison of metabolic pathways between cancer cells and stromal cells in colorectal carcinomas: a metabolic survival role for tumor-associated stroma

Understanding tumor metabolism is important for the development of anticancer therapies. Immunohistochemical evaluation of colorectal adenocarcinomas showed that cancer cells share common enzyme/transporter activities suggestive of an anaerobic metabolism [high lactate dehydrogenase 5 (LDH5)/hypoxia-inducible factor alphas (HIFalphas)] with high ability for glucose absorption and lactate extrusion [high glucose transporter 1 (GLUT1)/monocarboxylate transporter (MCT1)]. The tumor-associated fibroblasts expressed proteins involved in lactate absorption (high MCT1/MCT2), lactate oxidation (high LDH1 and low HIFalphas/LDH5), and reduced glucose absorption (low GLUT1). The expression profile of the tumor-associated endothelium indicated aerobic metabolism (high LDH1 and low HIFalphas/LDH5), high glucose absorption (high GLUT1), and resistance to lactate intake (lack of MCT1). It is suggested that the newly formed stroma and vasculature express complementary metabolic pathways, buffering and recycling products of anaerobic metabolism to sustain cancer cell survival. Tumors survive and grow because they are capable of organizing the regional fibroblasts and endothelial cells into a harmoniously collaborating metabolic domain.