The Mycoplasma hyorhinis p37 Protein Rapidly Induces Genes in Fibroblasts Associated with Inflammation and Cancer

The p37 protein at the surface of Mycoplasma hyorhinis cells forms part of a high-affinity transport system and has been found associated with animal and human cancers. Here we show in NIH3T3 fibroblasts, p37 rapidly induces the expression of genes implicated in inflammation and cancer progression. This gene activation was principally via the Tlr4 receptor. Activity was lost from p37 when the C-terminal 20 amino acids were removed or the four amino acids specific for the hydrogen bonding of thiamine pyrophosphate had been replaced by valine. Blocking the IL6 receptor or inhibiting STAT3 signalling resulted in increased p37-induced gene expression. Since cancer associated fibroblasts support growth, invasion and metastasis via their ability to regulate tumour-related inflammation, the rapid induction in fibroblasts of pro-inflammatory genes by p37 might be expected to influence cancer development.

ARTD1 Suppresses Interleukin 6 Expression by Repressing MLL1-Dependent Histone H3 Trimethylation

ADP-ribosyltransferase diphtheria-toxin like 1/poly(ADP-ribose) polymerase 1 (ARTD1/PARP1) is a chromatin-associated protein in the nucleus and plays an important role in different cellular processes such as regulation of gene transcription. ARTD1 has been shown to coregulate the inflammatory response by modulating the activity of the transcription factor nuclear factor κB (NF-κB), the principal regulator of interleukin 6 (IL-6), an important inflammatory cytokine implicated in a variety of diseases such as cancer. However, to what extent and how ARTD1 regulates IL-6 transcription has not been clear. Here, we show that ARTD1 suppresses lipopolysaccharide (LPS)-induced IL-6 expression in macrophages, without affecting the recruitment of the NF-κB subunit RelA to the IL-6 promoter and independent of its enzymatic activity. Interestingly, knockdown of ARTD1 did not alter H3 occupancy but increased LPS-induced trimethylation of histone 3 at lysine 4 (H3K4me3), a hallmark of transcriptionally active genes. We found that ARTD1 mediates its effect through the methyltransferase MLL1, by catalyzing H3K4me3 at the IL-6 promoter and forming a complex with NF-κB. These results demonstrate that ARTD1 modulates IL-6 expression by regulating the function of an NF-κB enhanceosome complex, which involves MLL1 and does not require ADP-ribosylation.

Skin fibrosis. Identification and isolation of a dermal lineage with intrinsic fibrogenic potential

Dermal fibroblasts represent a heterogeneous population of cells with diverse features that remain largely undefined. We reveal the presence of at least two fibroblast lineages in murine dorsal skin. Lineage tracing and transplantation assays demonstrate that a single fibroblast lineage is responsible for the bulk of connective tissue deposition during embryonic development, cutaneous wound healing, radiation fibrosis, and cancer stroma formation. Lineage-specific cell ablation leads to diminished connective tissue deposition in wounds and reduces melanoma growth. Using flow cytometry, we identify CD26/DPP4 as a surface marker that allows isolation of this lineage. Small molecule-based inhibition of CD26/DPP4 enzymatic activity during wound healing results in diminished cutaneous scarring. Identification and isolation of these lineages hold promise for translational medicine aimed at in vivo modulation of fibrogenic behavior.

Cancer-associated fibroblasts from lung tumors maintain their immunosuppressive abilities after high-dose irradiation

Accumulating evidence supports the notion that high-dose (>5 Gy) radiotherapy (RT) regimens are triggering stronger pro-immunogenic effects than standard low-dose (2 Gy) regimens. However, the effects of RT on certain immunoregulatory elements in tumors remain unexplored. In this study, we have investigated the effects of high-dose radiotherapy (HD-RT) on the immunomodulating functions of cancer-associated fibroblasts (CAFs). Primary CAF cultures were established from lung cancer specimens derived from patients diagnosed for non-small cell lung cancer. Irradiated and non-irradiated CAFs were examined for immunomodulation in experiments with peripheral blood mononuclear cells from random, healthy donors. Regulation of lymphocytes behavior was checked by lymphocyte proliferation assays, lymphocyte migration assays, and T-cell cytokine production. Additionally, CAF-secreted immunoregulatory factors were studied by multiplex protein arrays, ELISAs, and by LC-MS/MS proteomics. In all functional assays, we observed a powerful immunosuppressive effect exerted by CAF-conditioned medium on activated T-cells (p > 0.001), and this effect was sustained after a single radiation dose of 18 Gy. Relevant immunosuppressive molecules such as prostaglandin E2, interleukin-6, and -10, or transforming growth factor-β were found in CAF-conditioned medium, but their secretion was unchanged after irradiation. Finally, immunogenic cell death responses in CAFs were studied by exploring the release of high motility group box-1 and ATP. Both alarmins remained undetectable before and after irradiation. In conclusion, CAFs play a powerful immunosuppressive effect over activated T-cells, and this effect remains unchanged after HD-RT. Importantly, CAFs do not switch on immunogenic cell death responses after exposure to HD-RT.

Metabolic reprogramming and inflammation act in concert to control vascular remodeling in hypoxic pulmonary hypertension

Pulmonary hypertension (PH) is a complex, multifactorial syndrome that remains poorly understood despite decades of research. PH is characterized by profound pulmonary artery (PA) remodeling that includes significant fibro-proliferative and inflammatory changes of the PA adventitia. In line with the emerging concept that PH shares key features with cancer, recent work centers on the idea that PH results from a multistep process driven by reprogramming of gene-expression patterns that govern changes in cell metabolism, inflammation, and proliferation. Data demonstrate that in addition to PA endothelial cells and smooth muscle cells, adventitial fibroblasts from animals with experimental hypoxic PH and from humans with PH (hereafter, termed PH-Fibs) exhibit proinflammatory activation, increased proliferation, and apoptosis resistance, all in the context of metabolic reprogramming to aerobic glycolysis. PH-Fibs can also recruit, retain, and activate naïve macrophages (Mϕ) toward a proinflammatory/proremodeling phenotype through secretion of chemokines, cytokines, and glycolytic metabolites, among which IL-6 and lactate play key roles. Furthermore, these fibroblast-activated Mϕ (hereafter, termed FAMϕ) exhibit aerobic glycolysis together with high expression of arginase 1, Vegfa, and I1lb, all of which require hypoxia-inducible factor 1α and STAT3 signaling. Strikingly, in situ, the adventitial Mϕ phenotype in the remodeled PA closely resembles the Mϕ phenotype induced by fibroblasts in vitro (FAMϕ), suggesting that FAMϕ crosstalk involving metabolic and inflammatory signals is a critical, pathogenetic component of vascular remodeling. This review discusses metabolic and inflammatory changes in fibroblasts and Mϕ in PH with the goal of raising ideas about new interventions to abrogate remodeling in hypoxic forms of PH.

Prognostic significance of pre-operative C-reactive protein and the neutrophil-lymphocyte ratio in resectable pancreatic cancer: a systematic review

BACKGROUND

Better pre-operative risk stratification may improve patient selection for pancreatic resection in pancreatic cancer. C-reactive protein (CRP) and the neutrophil-lymphocyte ratio (NLR) have demonstrated prognostic value in some cancers. The role of CRP and NLR in predicting outcome in pancreatic cancer after curative resection is not well established.

METHODS

An electronic search of MEDLINE, EMBASE and CINAHL was performed to identify studies assessing survival in patients after pancreatic cancer resection with high or low pre-operative CRP or NLR. Systematic review was undertaken using the PRISMA protocol.

RESULTS

In total, 327 studies were identified with 10 reporting on survival outcomes after a pancreatic resection in patients with high or low CRP, NLR or both. All but one paper showed a trend of lower inflammatory markers in patients with longer survival. Three studies from six showed low CRP to be independently associated with increased survival and two studies of eight showed the same for NLR. All studies were retrospective cohort studies of low to moderate quality.

DISCUSSION

Inflammatory markers might prove useful guides to the management of resectable pancreatic cancer but, given the poor quality of evidence, further longitudinal studies are required before incorporating pre-operative inflammatory markers into clinical decision making.

Molecular mechanism underlying the tumor-promoting functions of carcinoma-associated fibroblasts

Tumor microenvironment is composed of all the untransformed elements in the vicinity of tumor, mainly including a large number of stromal cells and extracellular matrix proteins, which play an active role in most solid tumor initiation and progression. Carcinoma-associated fibroblasts (CAFs), one of the most common stromal cell types in the tumor microenvironment, have been demonstrated to be involved in tumor growth, invasion, and metastasis. Therefore, they are becoming a promising target for anti-cancer therapies. In this review, we firstly summarize the current understandings of CAFs' molecular biology, including the heterogeneous cellular origins and molecular markers, and then, we focus on reviewing their various tumor-promoting phenotypes involved in complex mechanisms, which can be summarized to the CAF-conveyed paracrine signals in tumor cells, cancer stem cells, and metastasis-initiating cancer cells, as well as the CAF-enhanced extrinsic tumor-promoting processes including angiogenesis, extracellular matrix remodeling, and tumor-related inflammation; finally, we describe the available directions of CAF-based target therapy and suggest research areas which need to be further explored so as to deepen the understanding of tumor evolution and provide new therapeutic targets for cancer treatment.

Tumor-derived osteopontin reprograms normal mammary fibroblasts to promote inflammation and tumor growth in breast cancer

Breast tumors are characterized by an extensive desmoplastic stroma, abundantly populated by fibroblasts. Cancer-associated fibroblasts (CAF) support tumorigenesis by stimulating angiogenesis, cancer cell proliferation, and invasion. CAF also orchestrate tumor-promoting inflammation in multiple tumor types, including breast cancer. However, the mechanisms through which normal tissue fibroblasts are reprogrammed to tumor-promoting CAFs are mainly obscure. Here, we show that mammary fibroblasts can be educated by breast cancer cells to become activated to a proinflammatory state that supports malignant progression. Proteomic analysis of breast cancer cell-secreted factors identified the secreted proinflammatory mediator osteopontin, which has been implicated in inflammation, tumor progression, and metastasis. Osteopontin was highly secreted by mouse and human breast cancer cells, and tumor cell-secreted osteopontin activated a CAF phenotypes in normal mammary fibroblasts in vitro and in vivo. Osteopontin was sufficient to induce fibroblast reprogramming and neutralizing antibodies against osteopontin-blocked fibroblast activation induced by tumor cells. The ability of secreted osteopontin to activate mammary fibroblasts relied upon its known receptors CD44 and αVβ3 integrin. Strikingly, osteopontin silencing in tumor cells in vivo attenuated stromal activation and inhibited tumor growth. Our findings establish a critical functional role for paracrine signaling by tumor-derived osteopontin in reprograming normal fibroblasts into tumor-promoting CAFs.

Stromal Expression of Fibroblast Activation Protein Alpha (FAP) Predicts Platinum Resistance and Shorter Recurrence in patients with Epithelial Ovarian Cancer

The microenvironment plays an important role in tumorigenesis. Fibroblast activation protein alpha (FAP) is overexpressed by fibroblasts present in the microenvironment of many tumors. High FAP expression is a negative prognostic factor in several malignancies, but this has not been investigated in epithelial ovarian cancer (EOC). The aim of this study is to define the value of FAP in EOC. Immunohistochemical staining using an anti-FAP antibody was performed on 338 EOC tissues. mRNA levels in cancer cell lines and FAP silencing using siRNA was also done. FAP immunoexpression by tumor stroma was a significant predictive factor for platinum resistance (p = 0.0154). In survival analysis of days to recurrence, FAP stoma (+) was associated with shorter recurrence than those with FAP (-) stroma (p = 0.0247). In 21.8 % of tumors, FAP protein was expressed by the tumor epithelium, and FAP mRNA was more highly expressed in tumors (n = 489) than in normal tissues (n = 8) (p = 3.88 × 10(-4)). In vitro, addition of FAP to EOC cells induced a 10-12 % increase in cell viability both in the presence and absence of cisplatin. Conversely, siRNA silencing of FAP resulted in ~10 % reduction in EOC cell proliferation. We have shown that FAP expression in EOC is associated with poorer clinical outcomes. FAP may have novel cell-autonomous effects suggesting that targeting FAP could have pleiotropic anti-tumor effects, and anti-FAP therapy could be a highly effective novel treatment for EOC, especially in cisplatinum-resistant cases.

[Advancement of relationship between metabolic alteration in cancer-associated fibroblasts and tumor progression in lung cancer]

肺癌的演进与“肿瘤微环境”变化密切相关，癌相关成纤维细胞（cancer-associated fibroblasts, CAFs）是被癌细胞“驯化”的成纤维细胞，是肿瘤微环境的重要成员之一。CAFs还具有促进肿瘤细胞生长、侵袭和转移的特性。研究表明CAFs的物质能量代谢方式与正常的成纤维细胞有明显不同。CAFs以糖酵解生成乳酸的方式进行代谢并将乳酸供给癌细胞，即CAFs表现为“反瓦伯格效应（reverse Warburg effect）”的代谢形式以适应和促进肿瘤细胞的演进。本文针对CAFs代谢转变与肺癌演进的关系，从以下五个方面进行综述：①CAFs的特性及其代谢特点；② CAFs代谢的研究现状；③CAFs代谢方式转变可能的分子机制；④CAFs代谢方式转变与肺癌演进的关系；⑤CAFs代谢方式的转变与肺癌预后和治疗的关系。

Crucial involvement of the CCL3-CCR5 axis-mediated fibroblast accumulation in colitis-associated carcinogenesis in mice

Patients with inflammatory bowel diseases often develop colon carcinoma. Combined treatment of azoxymethane (AOM) and dextran sulfate sodium (DSS) recapitulates colitis-associated cancer in mice. AOM/DSS-induced tumor formation was reduced in CCL3- or its specific receptor, CCR5-deficient mice despite the presence of a massive infiltration of inflammatory cells. However, AOM/DSS-induced type I collagen-positive fibroblast accumulation in the colon was reduced in CCL3- or CCR5-deficient mice. This was associated with depressed expression of heparin-binding epidermal growth factor-like growth factor (HB-EGF), which is expressed mainly by fibroblasts. Moreover in vitro, CCL3 induced fibroblasts to proliferate and to enhance HB-EGF expression. Furthermore, CCR5 blockade reduced tumor formation together with reduced fibroblast accumulation and HB-EGF expression, even when administered after the development of multiple colon tumors. Thus, CCL3-CCR5-mediated fibroblast accumulation may be required, in addition to leukocyte infiltration, to induce full-blown colitis-associated carcinogenesis. Our studies shed light on a therapeutic potential of CCR5 antagonist for patients with colitis-associated cancer.

A pro-tumourigenic loop at the human prostate tumour interface orchestrated by oestrogen, CXCL12 and mast cell recruitment

Prostate cancer is hormone-dependent and regulated by androgens as well as oestrogens. The tumour microenvironment also provides regulatory control, but the balance and interplay between androgens and oestrogens at the human prostate tumour interface is unknown. This study reveals a central and dominant role for oestrogen in the microenvironment, fuelling a pro-tumourigenic loop of inflammatory cytokines involving recruitment of mast cells by carcinoma-associated fibroblasts (CAFs). Mast cell numbers were increased in human PCa clinical specimens, specifically within the peritumoural stroma. Human mast cells were also shown to express ERα and ERβ, with oestradiol directly stimulating mast cell proliferation and migration as well as altered cytokine/chemokine expression. There was a significant shift in the oestrogen:androgen balance in CAFs versus normal prostatic fibroblasts (NPFs), with a profound increase to ER:AR expression. Androgen signalling is also reduced in CAFs, while ERα and ERβ transcriptional activity is not, allowing oestrogen to dictate hormone action in the tumour microenvironment. Gene microarray analyses identified CXCL12 as a major oestrogen-driven target gene in CAFs, and CAFs recruit mast cells via CXCL12 in a CXCR4-dependent manner. Collectively, these data reveal multicellular oestrogen action in the tumour microenvironment and show dominant oestrogen, rather than androgen, signalling at the prostatic tumour interface.

Cancer associated fibroblasts and tumor growth: focus on multiple myeloma

Cancer associated fibroblasts (CAFs) comprise a heterogeneous population that resides within the tumor microenvironment. They actively participate in tumor growth and metastasis by production of cytokines and chemokines, and the release of pro-inflammatory and pro-angiogenic factors, creating a more supportive microenvironment. The aim of the current review is to summarize the origin and characteristics of CAFs, and to describe the role of CAFs in tumor progression and metastasis. Furthermore, we focus on the presence of CAFs in hypoxic conditions in relation to multiple myeloma disease.

Carboxymethylcellulose hydrogels support central nervous system-derived tumor-cell chemotactic migration: Comparison with conventional extracellular matrix macromolecules

The local microenvironment plays an important role in maintaining the dynamics of the extracellular matrix and the cell–extracellular matrix relationship. The extracellular matrix is a complex network of macromolecules with distinct mechanical and biochemical characteristics. Disruptions in extracellular matrix homeostasis are associated with the onset of cancer. The extracellular matrix becomes highly disorganized, and the cell–matrix relationship changes, resulting in altered cell-signaling processes and metastasis. Medulloblastoma is one of the most common malignant pediatric brain tumors in the United States. In order to gain a better understanding of the interplay between cell–extracellular matrix interactions and cell-migratory responses in tumors, eight different matrix macromolecule formulations were investigated using a medulloblastoma-derived cell line: poly-d-lysine, matrigel, laminin, collagen 1, fibronectin, a 10% blend of laminin–collagen 1, a 20% blend of laminin–collagen 1, and a cellulose-derived hydrogel, carboxymethylcellulose. Over time, the average changes in cell morphology were quantified in 2D and 3D, as was migration in the presence and absence of the chemoattractant, epidermal growth factor. Data revealed that carboxymethylcellulose allowed for a cell–extracellular matrix relationship typically believed to be present in tumors, with cells exhibiting a rounded, amoeboid morphology consistent with chemotactic migration, while the other matrices promoted an elongated cell shape as well as both haptotactic and chemotactic motile processes. Therefore, carboxymethylcellulose hydrogels may serve as effective platforms for investigating central nervous system-derived tumor-cell migration in response to soluble factors.

Cancer-associated fibroblasts as another polarized cell type of the tumor microenvironment

Tumor- or cancer-associated fibroblasts (CAFs) are one of the most abundant stromal cell types in different carcinomas and comprise a heterogeneous cell population. Classically, CAFs are assigned with pro-tumorigenic effects stimulating tumor growth and progression. More recent studies demonstrated also tumor-inhibitory effects of CAFs suggesting that tumor-residing fibroblasts exhibit a similar degree of plasticity as other stromal cell types. Reciprocal interactions with the tumor milieu and different sources of origin are emerging as two important factors underlying CAF heterogeneity. This review highlights recent advances in our understanding of CAF biology and proposes to expand the term of cellular “polarization,” previously introduced to describe different activation states of various immune cells, onto CAFs to reflect their phenotypic diversity.

Glioblastoma-associated stromal cells (GASCs) from histologically normal surgical margins have a myofibroblast phenotype and angiogenic properties

Glioblastoma (GB) displays diffusely infiltrative growth patterns. Dispersive cells escape surgical resection and contribute to tumour recurrence within a few centimeters of the resection cavity in 90% of cases. We know that the non-neoplastic stromal compartment, in addition to infiltrative tumour cells, plays an active role in tumour recurrence. We isolated a new stromal cell population from the histologically normal surgical margins of GB by computer-guided stereotaxic biopsies and primary culture. These GB-associated stromal cells (GASCs) share phenotypic and functional properties with the cancer-associated fibroblasts (CAFs) described in the stroma of carcinomas. In particular, GASCs have tumour-promoting effects on glioma cells in vitro and in vivo. Here, we describe a quantitative proteomic analysis, using iTRAQ labelling and mass spectrometry, to compare GASCs with control stromal cells derived from non-GB peripheral brain tissues. A total of 1077 proteins were quantified and 67 proteins were found to differ between GASCs and control stromal cells. Several proteins changed in GASCs are related to a highly motile myofibroblast phenotype, and to wound healing and angiogenesis. The results for several selected proteins were validated by western blotting or flow cytometry. Furthermore, the effect of GASCs on angiogenesis was confirmed using the orthotopic U87MG glioma model. In conclusion, GASCs, isolated from GB histologically normal surgical margins and found mostly near blood vessels, could be a vascular niche constituent establishing a permissive environment, facilitating angiogenesis and possibly colonization of recurrence-initiating cells. We identify various proteins as being expressed in GASCs: some of these proteins may serve as prognostic factors for GB and/or targets for anti-glioma treatment.

Regulation of the anti-tumour immune response by cancer-associated fibroblasts

The microenvironment of established tumours is often immunosuppressed, and this allows tumours to grow and disseminate without being eliminated by the patient's immune system. The recent FDA approval of immunotherapies such as ipilimumab and sipuleucel-T that directly activate the adaptive and innate immune responses has triggered interest in developing other novel anti-cancer approaches that modulate the immune system. Understanding how the different constituents of the tumour microenvironment influence the immune system is thus crucial and is expected to generate a plethora of factors that can be targeted to boost immunity and trigger long lasting anti-tumour efficacy. Cancer associated fibroblasts (CAFs) are a crucial component of the tumour microenvironment. Through secretion of multiple growth factors, cytokines and proteases, CAFs are known to be key effectors for tumour progression and can promote cancer cell growth, invasiveness and angiogenesis. However, recent publications have also linked CAF biology to innate and adaptive immune cell recruitment and regulation. Here, we review recent findings on how CAFs can influence the immune status of tumours through direct and indirect interaction with immune cells and other key components of the tumour microenvironment.

Clinical Implications of Marker Expression of Carcinoma-Associated Fibroblasts (CAFs) in Patients with Epithelial Ovarian Carcinoma After Treatment with Neoadjuvant Chemotherapy

Cancer-associated fibroblasts (CAFs) play an important role in tumor initiation and progression. The aim of this study is to explore the role of 2 CAF markers, fibroblast activated protein (FAP) and α-smooth muscle actin (αSMA), in patients with epithelial ovarian cancer (EOC) post-neoadjuvant chemotherapy. Sixty-six patients with the diagnosis of EOC treated with debulking surgery after neoadjuvant therapy were retrieved from the archives. Immunohistochemistry for FAP and αSMA antibodies were performed on paraffin-embedded tissue. Fisher's exact test was performed to test the association between FAP and αSMA expression and disease status. Kaplan-Meier method with log-rank test was used to check the survival difference between different FAP tumor/stroma expressions. FAP stroma (pos) . expression was strongly associated with higher recurrences rate [OR: 15.95; 95 % CI: 1.521-835.206; p = 0.0072]. Cases with combined FAP stroma (pos) and FAP tumor (neg) had higher death rate [OR: 4.845; 95 % CI: 1.53-16.61; p = 0.0046] and higher recurrence rate [OR: 5.12; 95 % CI: 0.91-54.42; p = 0.0487] compared to all the others. Cases with combined FAP stroma (neg) and FAP tumor (neg) were more likely to have lower recurrence rates [OR: 0.086; 95 % CI: 0.001-0.997; p = 0.0248]. αSMA was expressed by tumor-associated stroma in 95 % of cases and by tumor cells in 9 % of cases. No statistical power was found for αSMA and disease status. Our data indicate that FAP plays an important role in predicting tumor aggressiveness in patients with EOC post-neoadjuvant therapy, and its frequent expression in this malignancy implicates that FAP targeted therapy could be a very attractive strategy.

TIMP-1 promotes accumulation of cancer associated fibroblasts and cancer progression

Treatment options for late stage prostate and colon cancer are limited and there is an urgent need to develop more effective and targeted novel therapies, which starts with identification and validation of novel therapeutic targets. Recent clinical studies have demonstrated that tissue inhibitor matrix metalloproteinase-1 (TIMP-1) levels are elevated in cancer patient plasma and elevated TIMP-1 levels are associated with worse clinical outcomes. However, it is unknown whether TIMP-1 serves merely as a biomarker of cancer progression or has a functional role in promoting cancer progression and can serve as a cancer therapeutic target, which is the main objective of this study. Here, we show that stroma of human prostate and colon cancer express higher levels of TIMP-1 compared to their normal counterparts and increased expression of TIMP-1 promotes in vivo growth of both cancer types. We demonstrate for the first time that increased TIMP-1 expression stimulates accumulation of cancer associated fibroblasts (CAFs) within prostate and colon cancer tissues and that TIMP-1 enhances prostate CAF proliferation and migration in vitro and promotes ERK1/2 kinase activation in these CAF cells. Our results establish the novel promotive effects of TIMP-1 on cancer progression and on accumulation of CAFs that in turn provides a pro-tumor microenvironment. Together, these results establish the potential of TIMP-1 as a novel target for cancer therapy and the mechanism underlying the pro-tumor activity of TIMP-1.

Cancer-associated fibroblasts and M2-polarized macrophages synergize during prostate carcinoma progression

Inflammation is now acknowledged as an hallmark of cancer. Cancer-associated fibroblasts (CAFs) force a malignant cross talk with cancer cells, culminating in their epithelial-mesenchymal transition and achievement of stemness traits. Herein, we demonstrate that stromal tumor-associated cells cooperate to favor malignancy of prostate carcinoma (PCa). Indeed, prostate CAFs are active factors of monocyte recruitment toward tumor cells, mainly acting through stromal-derived growth factor-1 delivery and promote their trans-differentiation toward the M2 macrophage phenotype. The relationship between M2 macrophages and CAFs is reciprocal, as M2 macrophages are able to affect mesenchymal-mesenchymal transition of fibroblasts, leading to their enhanced reactivity. On the other side, PCa cells themselves participate in this cross talk through secretion of monocyte chemotactic protein-1, facilitating monocyte recruitment and again macrophage differentiation and M2 polarization. Finally, this complex interplay among cancer cells, CAFs and M2 macrophages, cooperates in increasing tumor cell motility, ultimately fostering cancer cells escaping from primary tumor and metastatic spread, as well as in activation of endothelial cells and their bone marrow-derived precursors to drive de novo angiogenesis. In keeping with our data obtained in vitro, the analysis of patients affected by prostate cancers at different clinical stages revealed a clear increase in the M2/M1 ratio in correlation with clinical values. These data, coupled with the role of CAFs in carcinoma malignancy to elicit expression of stem-like traits, should focus great interest for innovative strategies aimed at the co-targeting of inflammatory cells and fibroblasts to improve therapeutic efficacy.

High levels of cleaved caspase-3 in colorectal tumour stroma predict good survival

Aim:

The primary aim was to determine the prognostic significance of apoptosis in colorectal tumour cells and tumour-associated stroma. A secondary aim was to determine whether apoptosis was related to immune surveillance.

Methods:

Immunohistochemistry was performed using monoclonal antibodies recognising cleaved caspase-3 (CC3), cleaved poly (ADP-ribose) polymerase (PARP), p53, Bcl2, MHC-II, B cells (CD16), macrophages (CD68) and T cells (CD3), on a tissue microarray of 462 colorectal tumours.

Results:

Kaplan–Meier analysis demonstrated that patients with high expression of CC3 in the tumour or CC3 or cleaved PARP in tumour-associated stroma have a good prognosis. This suggests that tumour stroma is promoting tumourigenesis and that high levels of death within the stroma breaks this link. CC3 levels in the tumour correlated with cleaved PARP and MHC-II expression but not with CD16, CD68, CD3, p53 or Bcl2 expression. CC3 levels on tumour-associated stroma also correlated with cleaved PARP and MHC-II expression but not with CD16, CD68, CD3, p53 or Bcl2 expression. Tumour cells express MHC-II in response to IFN-γ, suggesting that this may be one of the initiators of apoptosis within the good prognosis tumours. Although 73% of the MHC-II-positive tumour had high levels of apoptosis, many tumours had high levels of apoptosis in the absence of MHC-II, implying that this is only one of many causes of apoptosis within tumours. On multivariate analysis, using Cox's proportional hazards model, tumour stage, vascular invasion and expression of CC3 in tumour-associated stroma were shown to be independent markers of prognosis.

Conclusion:

This study shows that a high level of apoptosis within colorectal tumour-associated stroma is an independent marker of good prognosis.

An inflammatory vicious cycle: Fibroblasts and immune cell recruitment in cancer

Cancer-associated fibroblasts (CAFs) have been established as a key component of the crosstalk between tumor cells and their microenvironment. The ability of CAFs to orchestrate tumor-promoting inflammation is central to their role in facilitating tumor growth, invasion, and metastasis. Here we review pathways by which CAFs and their soluble mediators provide multiple complex signals that modulate the recruitment, functional activation status, and retention of immune cells in the tumor microenvironment.

Inflammation, wound repair, and fibrosis: reassessing the spectrum of tissue injury and resolution

Estimates from various disease-specific registries suggest that chronic inflammatory and fibrotic disorders affect a large proportion of the world's population, yet therapies for these conditions are largely ineffective. Recent advances in our collective understanding of mechanisms underlying both physiological and pathological repair of tissue injury are informing new clinical approaches to deal with various human inflammatory and fibrotic diseases. This 2013 Annual Review Issue of The Journal of Pathology offers an up-to-date glimpse of ongoing research in the fields of inflammation, wound healing, and tissue fibrosis, and highlights novel pathways and mechanisms that may be exploited to provide newer, more effective treatments to patients worldwide suffering from these conditions.