ICAM-1 mediated peritoneal carcinomatosis, a target for therapeutic intervention

Cellular Senescence in Liver Cancer: How Dying Cells Become "Zombie" Enemies

Liver cancer represents the fourth leading cause of cancer-associated death worldwide. The heterogeneity of its tumor microenvironment (TME) is a major contributing factor of metastasis, relapse, and drug resistance. Regrettably, late diagnosis makes most liver cancer patients ineligible for surgery, and the frequent failure of non-surgical therapeutic options orientates clinical research to the investigation of new drugs. In this context, cellular senescence has been recently shown to play a pivotal role in the progression of chronic inflammatory liver diseases, ultimately leading to cancer. Moreover, the stem-like state triggered by senescence has been associated with the emergence of drug-resistant, aggressive tumor clones. In recent years, an increasing number of studies have emerged to investigate senescence-associated hepatocarcinogenesis and its derived therapies, leading to promising results. In this review, we intend to provide an overview of the recent evidence that unveils the role of cellular senescence in the most frequent forms of primary and metastatic liver cancer, focusing on the involvement of this mechanism in therapy resistance.

Targeting Hyaluronic Acid and Peritoneal Dissemination in Colorectal Cancer

Peritoneal metastasis (PM) from colorectal cancer (CRC) carries a significant mortality rate for patients and treatment is challenging. The development of PM is a multistep process involving detachment, adhesion, invasion and colonization of the peritoneal cavity. Cytoreductive surgery and HIPEC (hyperthermic intraperitoneal chemotherapy) for PM from CRC has some benefit but overall survival is poor and recurrence rates are high. Treatments to prevent the development of peritoneal metastasis could have the potential to improve CRC survival and disease-free outcomes. The ability of cancer cells to invade the peritoneum and become established as metastatic tumors is influenced by a multifactorial process. Hyaluronic acid (HA) has been shown to coat the mesothelial cells of the peritoneum and has been demonstrated to be utilized in various malignancies as part of the metastatic process in peritoneal dissemination. CD44, RHAMM (CD168) and ICAM-1 have all been shown to be binding partners for HA. Targeting HA-mediated binding may prevent adhesion to distant sites within the peritoneum through suppression of interaction of these molecules. Here we review the current literature and discuss key molecules involved with PM dissemination, with the potential to target these mechanisms in the delivery of future treatments.

Obesity and inflammation: colorectal cancer engines

The prevalence of obesity continues to increase to the extent that it became a worldwide pandemic. An accumulating body of evidence has associated obesity with the development of different types of cancer, including colorectal cancer, which is a notorious disease with a high mortality rate. At the molecular level, colorectal cancer is a heterogenous disease characterized by a myriad of genetic and epigenetic alterations associated with various forms of genomic instability (detailed in Supplementary Materials). Recently, the microenvironment has emerged as a major factor in carcinogenesis. Our aim is to define the different molecular alterations leading to the development of colorectal cancer in obese patients with a focus on the role of the microenvironment in carcinogenesis. We also highlight all existent molecules in clinical trials that target the activated pathways in obesity-associated colorectal cancer, whether used as single treatments or in combination. Obesity predisposes to colorectal cancer via creating a state of chronic inflammation with dysregulated adipokines, inflammatory mediators, and other factors such as immune cell infiltration. A unifying theme in obesity-mediated colorectal cancer is the activation of the PI3K/AKT, mTOR/MAPK, and STAT3 signaling pathways. Different inhibitory molecules towards these pathways exist, increasing the therapeutic choice of obesity-associated colon cancer. However, obese patients are more likely to suffer from chemotherapy overdosing. Preventing obesity through maintaining a healthy and active lifestyle remains to be the best remedy.

Helper T cells in malignant pleural effusion

Malignant pleural effusion (MPE) is a frequent complication of malignancies and poses a clinical problem. CD4⁺ T lymphocytes are the most frequent cell population in MPE. Traditionally, CD4⁺ T cells are classified into two subsets based on cytokine production profiles, type 1 (Th1) and type 2 (Th2) helper T cells, which exhibit distinct functions. Recently, other T-cell subsets have been added to the Th-cell "portfolio", including regulatory T, Th17, Th9, and Th22 cells. The current review focuses on summarizing the Th-cell phenotypic characteristics, mechanism of Th-cell differentiation, and their pleural space recruitment, based on recent research. We also describe the interplay in MPE among different Th cells, as well as Th cells and lung cancer cells or mesothelial cells. Future research should expand the landscape map of human MPE immune cells, explore the immuno-regulation of B cells, and investigate the communication between macrophages and Th cells in MPE, which may facilitate meaningful advancements in the diagnoses and therapeutics of MPE.

Exosomal miR-21-5p derived from gastric cancer promotes peritoneal metastasis via mesothelial-to-mesenchymal transition

Peritoneal metastasis is a primary metastatic route for gastric cancers, and the mechanisms underlying this process are still unclear. Peritoneal mesothelial cells (PMCs) undergo mesothelial-to-mesenchymal transition (MMT) to provide a favorable environment for metastatic cancer cells. In this study, we investigated how the exosomal miR-21-5p induces MMT and promotes peritoneal metastasis. Gastric cancer (GC)-derived exosomes were identified by transmission electron microscopy and western blot analysis, then the uptake of exosomes was confirmed by PKH-67 staining. The expression of miR-21-5p and SMAD7 were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot, and the interactions between miR-21-5p and its target genes SMAD7 were confirmed by Luciferase reporter assays. The MMT of PMCs was determined by invasion assays, adhesion assays, immunofluorescent assay, and western blot. Meanwhile, mouse model of tumor peritoneal dissemination model was performed to investigate the role of exosomal miR-21-5p in peritoneal metastasis in vivo. We found that PMCs could internalize GC-derived exosomal miR-21-5p and led to increased levels of miR-21-5p in PMCs. Through various types of in vitro and in vivo assays, we confirmed that exosomal miR-21-5p was able to induce MMT of PMCs and promote tumor peritoneal metastasis. Moreover, our study revealed that this process was promoted by exosomal miR-21-5p through activating TGF-β/Smad pathway via targeting SMAD7. Altogether, our data suggest that exosomal miR-21-5p induces MMT of PMCs and promote cancer peritoneal dissemination by targeting SMAD7. The exosomal miR-21-5p may be a novel therapeutic target for GC peritoneal metastasis.

Role of tumor microenvironment in the pathobiology of ovarian cancer: Insights and therapeutic opportunities

Ovarian cancer is the fifth most common cancer affecting women and at present, stands as the most lethal gynecologic malignancy. The poor disease outcome is due to the nonspecific symptoms and the lack of effective treatment at advanced stages. Thus, it is of utmost importance to understand ovarian carcinoma through several lenses and to dissect the role that the unique peritoneal tumor microenvironment plays in ovarian cancer progression and metastasis. This review seeks to highlight several determinants of this unique tumor microenvironment, their influence on disease outcome and ongoing clinical trials targeting these determinants.

Adhesion in Physiological, Benign and Malignant Proliferative States of the Endometrium: Microenvironment and the Clinical Big Picture

Although the developments in cellular and molecular biology over the last few decades have significantly advanced our understanding of the processes and players that regulate invasive disease, many areas of uncertainty remain. This review will discuss the contribution of dysregulated cell⁻cell and cell⁻matrix adhesion to the invasion in both benign and malignant contexts. Using the endometrium as an illustrative tissue that undergoes clinically significant invasion in both contexts, the adhesion considerations in the cells ("seed") and their microenvironment ("soil") will be discussed. We hope to orientate this discussion towards translational relevance for the diagnosis and treatment of endometrial conditions, which are currently associated with significant morbidity and mortality.

Procancerogenic activity of senescent cells: A case of the peritoneal mesothelium

Human peritoneal mesothelial cells belong to a narrow group of somatic cells in which both the triggers and the mechanisms of senescence have already been well defined. Importantly, senescent mesothelial cells have been found in the peritoneal cavity in vivo. From a clinical point of view, peritoneal mesothelial cells have been recognized as playing a critical role in the intraperitoneal development of tumor metastases. The pro-cancerogenic behavior of mesothelial cells is even more pronounced when the cells exhaust their proliferative capacity and become senescent. In this review, we summarize the current state of art regarding the contribution of peritoneal mesothelial cells in the progression of ovarian, colorectal, and pancreatic carcinomas, with particular attention paid to the cancer-promoting activity of their senescent counterparts. Moreover, we delineate the mechanisms, mediators, and signaling pathways that are engaged by the senescent mesothelial cells to support such vital elements of cancer progression as adhesion, proliferation, migration, invasion, epithelial-mesenchymal transition, and angiogenesis. Finally, we discuss the experimental evidence regarding both natural and synthetic compounds that may either prevent or restrict cancer development by delaying senescence of mesothelial cells.

Role of tumor microenvironment in ovarian cancer pathobiology

Ovarian cancer is the fifth most common cancer affecting the female population and at present, stands as the most lethal gynecologic malignancy. Poor prognosis and low five-year survival rate are attributed to nonspecific symptoms and below par diagnostic criteria at early phases along with a lack of effective treatment at advanced stages. It is thus of utmost importance to understand ovarian carcinoma through several lenses including its molecular pathogenesis, epidemiology, histological subtypes, hereditary factors, diagnostic approaches and methods of treatment. Above all, it is crucial to dissect the role that the unique peritoneal tumor microenvironment plays in ovarian cancer progression and metastasis. This review seeks to highlight several important aspects of ovarian cancer pathobiology as a means to provide the necessary background to approach ovarian malignancies in the future.

The peritoneal "soil" for a cancerous "seed": a comprehensive review of the pathogenesis of intraperitoneal cancer metastases

Various types of tumors, particularly those originating from the ovary and gastrointestinal tract, display a strong predilection for the peritoneal cavity as the site of metastasis. The intraperitoneal spread of a malignancy is orchestrated by a reciprocal interplay between invading cancer cells and resident normal peritoneal cells. In this review, we address the current state-of-art regarding colonization of the peritoneal cavity by ovarian, colorectal, pancreatic, and gastric tumors. Particular attention is paid to the pro-tumoral role of various kinds of peritoneal cells, including mesothelial cells, fibroblasts, adipocytes, macrophages, the vascular endothelium, and hospicells. Anatomo-histological considerations on the pro-metastatic environment of the peritoneal cavity are presented in the broader context of organ-specific development of distal metastases in accordance with Paget's "seed and soil" theory of tumorigenesis. The activity of normal peritoneal cells during pivotal elements of cancer progression, i.e., adhesion, migration, invasion, proliferation, EMT, and angiogenesis, is discussed from the perspective of well-defined general knowledge on a hospitable tumor microenvironment created by the cellular elements of reactive stroma, such as cancer-associated fibroblasts and macrophages. Finally, the paper addresses the unique features of the peritoneal cavity that predispose this body compartment to be a niche for cancer metastases, presents issues that are topics of an ongoing debate, and points to areas that still require further in-depth investigations.

Surgical stress response and promotion of metastasis in colorectal cancer: a complex and heterogeneous process

Surgery remains the curative treatment modality for colorectal cancer in all stages, including stage IV with resectable liver metastasis. There is emerging evidence that the stress response caused by surgery as well as other perioperative therapies such as anesthesia and analgesia may promote growth of pre-existing micro-metastasis or potentially initiate tumor dissemination. Therapeutically targeting the perioperative period may therefore reduce the effect that surgical treatments have in promoting metastases, for example by combining β-adrenergic receptor antagonists and cyclooxygenase-2 (COX-2) inhibitors in the perioperative setting. In this paper, we highlight some of the mechanisms that may underlie surgery-related metastatic development in colorectal cancer. These include direct tumor spillage at the time of surgery, suppression of the anti-tumor immune response, direct stimulatory effects on tumor cells, and activation of the coagulation system. We summarize in more detail results that support a role for catecholamines as major drivers of the pro-metastatic effect induced by the surgical stress response, predominantly through activation of β-adrenergic signaling. Additionally, we argue that an improved understanding of surgical stress-induced dissemination, and more specifically whether it impacts on the level and nature of heterogeneity within residual tumor cells, would contribute to the successful clinical targeting of this process. Finally, we provide a proof-of-concept demonstration that ex-vivo analyses of colorectal cancer patient-derived samples using RGB-labeling technology can provide important insights into the heterogeneous sensitivity of tumor cells to stress signals. This suggests that intra-tumor heterogeneity is likely to influence the efficacy of perioperative β-adrenergic receptor and COX-2 inhibition, and that ex-vivo characterization of heterogeneous stress response in tumor samples can synergize with other models to optimize perioperative treatments and further improve outcome in colorectal and other solid cancers.

Development of Peritoneal Carcinomatosis in Epithelial Ovarian Cancer: A Review

Epithelial ovarian cancer (EOC) metastasizes intra-abdominally with often numerous, superficial, small-sized lesions. This so-called peritoneal carcinomatosis is difficult to treat, and peritoneal recurrences are frequently observed, leading to a poor prognosis. Underlying mechanisms of interactions between EOC and peritoneal cells are incompletely understood. This review summarizes and discusses the development of peritoneal carcinomatosis from a cell-biological perspective, focusing on characteristics of EOC and peritoneal cells. We aim to provide insight into how peritoneum facilitates tumor adhesion but limits size of lesions and depth of invasion. The development of peritoneal carcinomatosis is a multistep process that requires adaptations of EOC and peritoneal cells. Mechanisms that enable tumor adhesion and growth involve cadherin restructuring on EOC cells, integrin-mediated adhesion, and mesothelial evasion by mechanical forces driven by integrin-ligand interactions. Clinical trials targeting these mechanisms, however, showed only limited effects. Other factors that inhibit tumor growth and deep invasion are virtually unknown. Future studies are needed to elucidate the exact mechanisms that underlie the development and limited growth of peritoneal carcinomatosis. This review on development of peritoneal carcinomatosis of EOC summarizes the current knowledge and its limitations. Clarification of the stepwise process may inspire future research to investigate new treatment approaches of peritoneal carcinomatosis.

Induction of Proteases in Peritoneal Carcinomatosis, the Role of ICAM-1/CD43 Interaction

Introduction

The development of peritoneal metastases is a significant clinical issue in the treatment of abdominal cancers and is associated with poor prognosis. We have previously shown that ICAM-1-CD43 interaction plays a significant role in tumor adhesion. However, an invasive phenotype is critical to establish tumor progression via cell associated and secreted proteases including matrix metalloproteinases. High metalloproteinases level significantly enhanced metastasis phenotype on tumors, a detrimental effect on surgical outcome. We investigated the role of direct and indirect signaling between the mesothelium and the tumor cells in enhancing tumor invasion and possible therapeutic intervention.

Methods

Mesothelial cells were enzymatically derived from human omental tissue and implanted in 24 wells plates. Colorectal cancer cells were then introduced and allowed a direct and an indirect contact with the mesothelial layer. Anti-ICAM antibodies, anti-CD43 antibodies, and heparin were used to block MMP production. Gelatin zymography was performed on the supernatant to detect MMPs activity.

Results

MMP production was observed in mesothelial and tumor cells. Direct contact between cell types enhanced MMP9 and 2 (p < 0.05). Indirect contact also stimulate MMPs but at a lower degree. ICAM-1 blocking antibodies attenuated MMP production in direct contact to that observed in the indirect. Heparin introduction achieved a similar outcome.

Conclusions

ICAM-1-CD43 interaction plays a vital role in tumor cells-peritoneum adhesion and invasion, which is manifested by the increased production of MMPs leading to tumor invasion and peritoneal loco-regional. Blocking this interaction with heparin can provide a new therapeutic option.

Oldenlandia diffusa suppresses metastatic potential through inhibiting matrix metalloproteinase-9 and intercellular adhesion molecule-1 expression via p38 and ERK1/2 MAPK pathways and induces apoptosis in human breast cancer MCF-7 cells

ETHNOPHARMACOLOGY RELEVANCE

Oldenlandia diffusa (OD) has long been known as an apoptotic inducer in breast tumors in ethnomedicine.

AIM OF THE STUDY

To scientifically confirm the anti-breast cancer effects of water, methanol (MeOH) and butanol (BuOH) extracts of O. diffusa on cell apoptosis, matrix metalloproteinases (MMPs), intercellular adhesion molecule (ICAM)-1 and intracellular signaling in MCF-7 breast cancer cells.

MATERIALS AND METHODS

MeOH extracts (MOD) and BuOH extracts (BOD) were prepared and examined for their ability to inhibit phorbol myristate acetate (PMA)-induced matrix metalloproteinase (MMP)-9 and intercellular adhesion molecule (ICAM)-1 expressions in MCF-7 human breast cancer cells. Additionally, transwell migration, invasion and transcriptional activity were assessed. Results of immunofluorescence confocal microscopy for translocation of NF-κB and p-ERK and p-p38 were also checked. Finally, apoptotic signals including processed caspase-8, caspase-7, poly ADP-ribose polymerase, Bax and Bcl-2 were examined.

RESULTS

MOD and BOD specifically inhibited PMA-induced MMP-9 expression as well as invasive and migration potential via ICAM-1. The inhibitory activity was also based on the suppressed transcriptional activity in MCF-7 breast cancer cells. Results of immunofluorescence confocal microscopy showed that translocation of NF-κB decreased upon BOD and MOD treatments, with a decreased level of p-ERK and p-p38 phosphorylation. In addition, treatment of MCF-7 cells with MOD and BOD activated apoptosis-linked proteins including enzymatically active forms of processed caspase-8, caspase-7 and poly ADP-ribose polymerase, together with increased expression of mitochondrial apoptotic protein, Bax and decreased expression of Bcl-2.

CONCLUSION

The results indicate that OD as an anti-metastatic agent suppresses the metastatic response by targeting p-ERK, p-38 and NF-κB, thus reducing the invasion capacity of MCF-7 breast cancer cells through inhibition of MMP-9 and ICAM-1 expression and plays an important role in the regulation of breast cancer cell apoptosis.

Cancer-associated peritoneal mesothelial cells lead the formation of pancreatic cancer peritoneal dissemination

The interaction between the cancer cells and the peritoneal mesothelial cells (PMCs) plays an important role in the peritoneal dissemination in several types of cancer. However, the role of PMCs in the peritoneal dissemination of pancreatic cancer remains unclear. In the present study, we investigated the interaction between the pancreatic cancer cells (PCCs) and the PMCs in the formation of peritoneal dissemination in vitro and in vivo. The tumor-stromal interaction of PCCs and PMCs significantly enhanced their mobility and invasiveness and enhanced the proliferation and anoikis resistance of PCCs. In a 3D organotypic culture model of peritoneal dissemination, co-culture of PCCs and PMCs significantly increased the cells invading into the collagen gel layer compared with mono-culture of PCCs. PMCs pre-invaded into the collagen gel, remodeled collagen fibers, and increased parallel fiber orientation along the direction of cell invasion. In the tissues of peritoneal dissemination of the KPC (LSL-KrasG12D/+; LSL-Trp53R172H/+;Pdx-1-Cre) transgenic mouse, the monolayer of PMCs was preserved in tumor-free areas, whereas PMCs around the invasive front of peritoneal dissemination proliferated and invaded into the muscle layer. In vivo, intraperitoneal injection of PCCs with PMCs significantly promoted peritoneal dissemination compared with PCCs alone. The present data suggest that the cancer-associated PMCs have important promoting roles in the peritoneal dissemination of PCCs. Therapy targeting cancer-associated PMCs may improve the prognosis of patients with pancreatic cancer.

Pathophysiology of colorectal peritoneal carcinomatosis: Role of the peritoneum

Colorectal cancer (CRC) is the third most common cancer and the fourth most common cause of cancer-related death worldwide. Besides the lymphatic and haematogenous routes of dissemination, CRC frequently gives rise to transcoelomic spread of tumor cells in the peritoneal cavity, which ultimately leads to peritoneal carcinomatosis (PC). PC is associated with a poor prognosis and bad quality of life for these patients in their terminal stages of disease. A loco-regional treatment modality for PC combining cytoreductive surgery and hyperthermic intraperitoneal peroperative chemotherapy has resulted in promising clinical results. However, this novel approach is associated with significant morbidity and mortality. A comprehensive understanding of the molecular events involved in peritoneal disease spread is paramount in avoiding unnecessary toxicity. The emergence of PC is the result of a molecular crosstalk between cancer cells and host elements, involving several well-defined steps, together known as the peritoneal metastatic cascade. Individual or clumps of tumor cells detach from the primary tumor, gain access to the peritoneal cavity and become susceptible to the regular peritoneal transport. They attach to the distant peritoneum, subsequently invade the subperitoneal space, where angiogenesis sustains proliferation and enables further metastatic growth. These molecular events are not isolated events but rather a continuous and interdependent process. In this manuscript, we review current data regarding the molecular mechanisms underlying the development of colorectal PC, with a special focus on the peritoneum and the role of the surgeon in peritoneal disease spread.

Colorectal cancer-promoting activity of the senescent peritoneal mesothelium

Gastrointestinal cancers metastasize into the peritoneal cavity in a process controlled by peritoneal mesothelial cells (HPMCs). In this paper we examined if senescent HPMCs can intensify the progression of colorectal (SW480) and pancreatic (PSN-1) cancers in vitro and in vivo. Experiments showed that senescent HPMCs stimulate proliferation, migration and invasion of SW480 cells, and migration of PSN-1 cells. When SW480 cells were injected i.p. with senescent HPMCs, the dynamics of tumor formation and vascularization were increased. When xenografts were generated using PSN-1 cells, senescent HPMCs failed to favor their growth. SW480 cells subjected to senescent HPMCs displayed up-regulated expression of transcripts for various pro-cancerogenic agents as well as increased secretion of their products. Moreover, they underwent an epithelial-mesenchymal transition in the Smad 2/3-Snail1-related pathway. The search for mediators of senescent HPMC activity showed that increased SW480 cell proliferation was stimulated by IL-6, migration by CXCL8 and CCL2, invasion by IL-6, MMP-3 and uPA, and epithelial-mesenchymal transition by TGF-β1. Secretion of these agents by senescent HPMCs was increased in an NF-κB- and p38 MAPK-dependent mechanism. Collectively, our findings indicate that in the peritoneum senescent HPMCs may create a metastatic niche in which critical aspects of cancer progression become intensified.

Adhesion molecules in peritoneal dissemination: function, prognostic relevance and therapeutic options

Peritoneal dissemination is diagnosed in 10–25 % of colorectal cancer patients. Selected patients are treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. For these patients, earlier diagnosis, optimised selection criteria and a personalised approach are warranted. Biomarkers could play a crucial role here. However, little is known about possible candidates. Considering tumour cell adhesion as a key step in peritoneal dissemination, we aim to provide an overview of the functional importance of adhesion molecules in peritoneal dissemination and discuss the prognostic, diagnostic and therapeutic options of these candidate biomarkers. A systematic literature search was conducted according to the PRISMA guidelines. In 132 in vitro, ex vivo and in vivo studies published between 1995 and 2013, we identified twelve possibly relevant adhesion molecules in various cancers that disseminate peritoneally. The most studied molecules in tumour cell adhesion are integrin α2β1, CD44 s and MUC16. Furthermore, L1CAM, EpCAM, MUC1, sLe^x and Le^x, chemokine receptors, Betaig-H3 and uPAR might be of clinical importance. ICAM1 was found to be less relevant in tumour cell adhesion in the context of peritoneal metastases. Based on currently available data, sLe^a and MUC16 are the most promising prognostic biomarkers for colorectal peritoneal metastases that may help improve patient selection. Different adhesion molecules appear expressed in haematogenous and transcoelomic spread, indicating two different attachment processes. However, our extensive assessment of available literature reveals that knowledge on metastasis-specific genes and their possible candidates is far from complete.

Animal models of colorectal peritoneal metastasis

Colorectal cancer remains an important cause of mortality worldwide. The presence of peritoneal carcinomatosis (PC) causes significant symptoms and is notoriously difficult to treat. Therefore, informative preclinical research into the mechanisms and possible novel treatment options of colorectal PC is essential in order to improve the prognostic outlook in these patients. Several syngeneic and xenograft animal models of colorectal PC were established, studying a wide range of experimental procedures and substances. Regrettably, more sophisticated models such as those giving rise to spontaneous PC or involving genetically engineered mice are lacking. Here, we provide an overview of all reported colorectal PC animal models and briefly discuss their use, strengths, and limitations.

Milky spots: omental functional units and hotbeds for peritoneal cancer metastasis

As the most common metastatic disease of abdomen pelvic cavity cancer, peritoneal carcinomatosis (PC) renders significant negative impact on patient survival and quality of life. Invasive peritoneal exfoliated cancer cells (PECCs) preferentially select the omentum as a predominant target site for cancer cell colonization and proliferation compared with other tissues in the abdominal cavity. The precise pathogenic mechanism remains to be determined. As omental milky spots (MSs) are the major implantation site for malignant cells in peritoneal dissemination, researches on mechanisms of PC have been mainly focused on MS, primitive lymphoid tissues with unique structural features, and functional characteristics. To date, extensive biophysical and biochemical methods have been manipulated to investigate the MS exact function in the peritoneal cavity. This review summarized MS as hotbeds for PECC. The anatomical distribution was briefly described first. Then, MS histology was systematically reviewed, including morphological features, cellular constituents, and histological staining methods. At last, the roles of MS in PC pathological process were summarized with special emphasis on the distinct roles of macrophages.

The Mesothelial Origin of Carcinoma Associated-Fibroblasts in Peritoneal Metastasis

Solid tumors are complex and unstructured organs that, in addition to cancer cells, also contain other cell types. Carcinoma-associated fibroblasts (CAFs) represent an important population in the tumor microenviroment and participate in several stages of tumor progression, including cancer cell migration/invasion and metastasis. During peritoneal metastasis, cancer cells detach from the primary tumor, such as ovarian or gastrointestinal, disseminate through the peritoneal fluid and colonize the peritoneum. Tumor cells metastasize by attaching to and invading through the mesothelial cell (MC) monolayer that lines the peritoneal cavity, then colonizing the submesothelial compact zone where CAFs accumulate. CAFs may derive from different sources depending on the surrounding metastatic niche. In peritoneal metastasis, a sizeable subpopulation of CAFs originates from MCs through a mesothelial-to-mesenchymal transition (MMT), which promotes adhesion, invasion, vascularization and subsequent tumor growth. The bidirectional communication between cancer cells and MC-derived CAFs via secretion of a wide range of cytokines, growth factors and extracellular matrix components seems to be crucial for the establishment and progression of the metastasis in the peritoneum. This manuscript provides a comprehensive review of novel advances in understanding how peritoneal CAFs provide cancer cells with a supportive microenvironment, as well as the development of future therapeutic approaches by interfering with the MMT in the peritoneum.

Response to pathological processes in the peritoneal cavity--sepsis, tumours, adhesions, and ascites

The peritoneum is one of the commonest sites for pathological processes in pediatric surgery. Its response to pathological processes is characterized by an inflammatory reaction with specific pathways depending on the type of injury or peritoneal process involved. This review discusses the current understanding of peritoneal inflammation, adhesion formation, intra-abdominal sepsis, peritoneal metastasis, and ascites and briefly reviews new therapeutic strategies to treat or prevent these pathological entities. Recent studies have improved the understanding of peritoneal responses, resulting in possible new targets for prevention and therapy.

Resveratrol inhibits ovarian cancer cell adhesion to peritoneal mesothelium in vitro by modulating the production of α5β1 integrins and hyaluronic acid

OBJECTIVE

Resveratrol (Res) is known to inhibit adhesion of numerous malignancies though its effect on an adherence of ovarian cancer cells to peritoneal mesothelium remains undefined.

METHODS

To address this issue, ovarian cancer cells (A2780, OVCAR-3, SKOV-3) were subjected to Res (10, 50, 100 μM), and then their adhesion to omentum-derived human peritoneal mesothelial cells (HPMCs) was assayed.

RESULTS

The study showed that Res inhibits adhesion of all ovarian cancer cell lines investigated. More importantly, this effect was evident either when cancer cells were directly treated with Res (cell-dependent activity) or when intact cancer cells were pretreated with conditioned medium (CM) generated by their counterparts subjected to Res (medium-dependent activity). Cell-dependent activity of Res has been recognized to be linked with decreased level of cellular α5β1 integrins which decreased functionality corresponds with reduced efficiency of cancer cell adhesion. Medium-related effects have been, in turn, associated with up-regulated secretion of soluble HA to environment (CM). The experiments with exogenous HA revealed the inverse relation between HA concentration in CM and cancer cell adhesion. When the CM from cells subjected with Res (with elevated HA) was supplemented with hyaluronidase, the restoration of cell adhesive capabilities occurred.

CONCLUSIONS

Our studies evidenced that Res affects ovarian cancer cell adhesion to HPMCs by decreasing cellular α5β1 integrin level and by increasing the secretion of HA to environment.

Carcinoma-associated fibroblasts derive from mesothelial cells via mesothelial-to-mesenchymal transition in peritoneal metastasis

Peritoneal dissemination is a frequent metastatic route for cancers of the ovary and gastrointestinal tract. Tumour cells metastasize by attaching to and invading through the mesothelial cell (MC) monolayer that lines the peritoneal cavity. Metastases are influenced by carcinoma-associated fibroblasts (CAFs), a cell population that derives from different sources. Hence, we investigated whether MCs, through mesothelial-mesenchymal transition (MMT), were a source of CAFs during peritoneal carcinomatosis and whether MMT affected the adhesion and invasion of tumour cells. Biopsies from patients with peritoneal dissemination revealed the presence of myofibroblasts expressing mesothelial markers in the proximity of carcinoma implants. Prominent new vessel formation was observed in the peritoneal areas harbouring tumour cells when compared with tumour-free regions. The use of a mouse model of peritoneal dissemination confirmed the myofibroblast conversion of MCs and the increase in angiogenesis at places of tumour implants. Treatment of omentum MCs with conditioned media from carcinoma cell cultures resulted in phenotype changes reminiscent of MMT. Adhesion experiments demonstrated that MMT enhanced the binding of cancer cells to MCs in a β1-integrin-dependent manner. Scanning electron microscopy imaging showed that the enhanced adhesion was mostly due to increased cell-cell interaction and not to a mere matrix exposure. Invasion assays suggested a reciprocal stimulation of the invasive capacity of tumour cells and MCs. Our results demonstrate that CAFs can derive from mesothelial cells during peritoneal metastasis. We suggest that MMT renders the peritoneum more receptive for tumour cell attachment/invasion and contributes to secondary tumour growth by promoting its vascularization.

Mesothelial cells differentiate into fibroblast-like cells under the scirrhous gastric cancer microenvironment and promote peritoneal carcinomatosis in vitro and in vivo

Peritoneal metastases are one reason for the poor prognosis of scirrhous gastric cancer (SGC), and myofibroblast provides a favorable environment for the peritoneal dissemination of gastric cancer. The aim of this study was to determine whether myofibroblast originates from peritoneal mesothelial cells under the influence of the tumor microenvironment. Immunohistochemical studies of peritoneal biopsy specimens from patients with peritoneal lavage cytological (+) status demonstrate the expression of the epithelial markers cytokeratin in fibroblast-like cells entrapped in the stroma, suggesting that these cells stemmed from local conversion of mesothelial cells. To confirm this hypothesis in vitro, we co-incubated mesothelial cells with SGC or non-SGC to investigate morphology and function changes. As we expected, mesothelial cells undergo a transition from an epithelial phenotype to a mesenchymal phenotype with loss of epithelial morphology and decrease in the expression of cytokeratin and E-cadherin when exposed to conditioned medium from HSC-39, and the induction of mesothelial cells can be abolished using a neutralizing antibody to transforming growth factor-beta1 (TGF-β1) as well as by pre-treatment with SB431542. Moreover, we found that these mesothelial cells-derived cells exhibit functional properties of myofibroblasts, including the ability to increase adhesion and invasion of SGC. In summary, our current data demonstrated that mesothelial cells are a source of myofibroblasts under the SGC microenvironment which provide a favorable environment for the dissemination of gastric cancer; TGF-β1 produced by autocrine/paracrine in peritoneal cavity may play a central role in this pathogenesis.

High adhesion of tumor cells to mesothelial monolayers derived from peritoneal wash of disseminated gastrointestinal cancers

The role of the mesothelial layer in the peritoneal spreading of cancer cells is only partially clarified. Here we attempted to better define the mesothelial contribution to the tumor cell adhesion using a direct adhesion test applied to human primary cultures of mesothelial cells (HPMCs) derived from the peritoneal washes of patients with gastric and colorectal cancers. Gastric and colon carcinoma cells were seeded on different mesothelial monolayers and quantitative fluorescence analysis was performed to analyze their growth and adhesive properties. The adhesion of the cancer cells was not affected by the origin of the HPMCs when derived from patients with different cancers or with benign disease. In contrast, the high levels of ICAM1 expression and ROS production, which characterize these senescent mesothelial cells, enhanced the tumor cell adhesion. These results suggest that the mesothelial adhesive properties are dependent on the cell senescence, while are not affected by the tumor environment. The use of peritoneal washes as a source to isolate HPMCs provides a practical and reliable tool for the in vitro analysis of the mesothelial conditions affecting the peritoneal carcinomatosis.

Interleukin 22-producing CD4+ T cells in malignant pleural effusion

Th22 cells have been reported to be involved in human cancers. However, differentiation and immune regulation of Th22 cells in malignant pleural effusion (MPE) remain unknown. We noted that Th22 cell numbers were increased in MPE, and that IL-22 substantially promoted the proliferation and migratory activity of A549 cells. Moreover, IL-22 could strongly facilitate intercellular adhesion of A549 cells to pleural mesothelial cell monolayers. Our data revealed that the increase in Th22 cells in MPE was due to pleural cytokines and chemokines, and that Th22 exerted an important immune regulation on cancer cells in human pleural malignant environment.

Cell-cell and cell-matrix dynamics in intraperitoneal cancer metastasis

The peritoneal metastatic route of cancer dissemination is shared by cancers of the ovary and gastrointestinal tract. Once initiated, peritoneal metastasis typically proceeds rapidly in a feed-forward manner. Several factors contribute to this efficient progression. In peritoneal metastasis, cancer cells exfoliate into the peritoneal fluid and spread locally, transported by peritoneal fluid. Inflammatory cytokines released by tumor and immune cells compromise the protective, anti-adhesive mesothelial cell layer that lines the peritoneal cavity, exposing the underlying extracellular matrix to which cancer cells readily attach. The peritoneum is further rendered receptive to metastatic implantation and growth by myofibroblastic cell behaviors also stimulated by inflammatory cytokines. Individual cancer cells suspended in peritoneal fluid can aggregate to form multicellular spheroids. This cellular arrangement imparts resistance to anoikis, apoptosis, and chemotherapeutics. Emerging evidence indicates that compact spheroid formation is preferentially accomplished by cancer cells with high invasive capacity and contractile behaviors. This review focuses on the pathological alterations to the peritoneum and the properties of cancer cells that in combination drive peritoneal metastasis.

Prognostic value of serum CD44, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 levels in patients with indolent non-Hodgkin lymphomas

Elevated serum CD44, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) have been linked to poor prognosis in aggressive lymphomas, but their utility in low grade lymphomas remains undefined. We evaluated serum CD44, VCAM-1 and ICAM-1 levels in 100 patients with newly diagnosed indolent NHL. The median pre-treatment values of the markers were as follows: CD44 540 ng/mL (range 156-1201), ICAM-1 311 ng/mL (range 102-1222) and VCAM-1 1165 ng/mL (range 248-4779). On univariate analysis, elevated sCD44, sICAM-1 and sVCAM-1 were significantly associated with worse overall (OS) and progression-free survival (PFS). In a subset analysis of patients with stage IV disease, the effects of sCD44 and sICAM-1 on OS persisted (p<0.05), as did the effect of sCD44 on PFS (p<0.01). In a multivariate analysis that included conventional prognostic factors and the Follicular Lymphoma International Prognostic Index (FLIPI) model, sICAM-1 demonstrated prognostic value for OS and PFS. We conclude that serum CD44, ICAM-1 and VCAM-1 can potentially be prognostic in patients with indolent NHL. Though the FLIPI model remains the gold standard for prognosis, these quantitative serologic markers may be useful as adjunct tools in assessing disease risk.

Phagocytosis of dying tumor cells by human peritoneal mesothelial cells

Peritoneal carcinomatosis is an advanced form of metastatic disease characterized by cancer cell dissemination onto the peritoneum. It is commonly observed in ovarian and colorectal cancers and is associated with poor patient survival. Novel therapies consist of cytoreductive surgery in combination with intraperitoneal chemotherapy, aiming at tumor cell death induction. The resulting dying tumor cells are considered to be eliminated by professional as well as semi-professional phagocytes. In the present study, we have identified a hitherto unknown type of 'amateur' phagocyte in this environment: human peritoneal mesothelial cells (HMCs). We demonstrate that HMCs engulf corpses of dying ovarian and colorectal cancer cells, as well as other types of apoptotic cells. Flow cytometric, confocal and electron microscopical analyses revealed that HMCs ingest dying cell fragments in a dose- and time-dependent manner and the internalized material subsequently traffics into late phagolysosomes. Regarding the mechanisms of prey cell recognition, our results show that HMCs engulf apoptotic corpses in a serum-dependent and -independent fashion and quantitative real-time PCR (qRT-PCR) analyses revealed that diverse opsonin receptor systems orchestrating dying cell clearance are expressed in HMCs at high levels. Our data strongly suggest that HMCs contribute to dying cell removal in the peritoneum, and future studies will elucidate in what manner this influences tumor cell dissemination and the antitumor immune response.

Induction of gastric cancer cell adhesion through transforming growth factor-beta1-mediated peritoneal fibrosis

Background

Peritoneal dissemination is one of the main causes of death in gastric cancer patients. Transforming growth factor-beta1 (TGF-β1), one of the most potent fibrotic stimuli for mesothelial cells, may play a key role in this processing. The purpose of this study is to elucidate the effects of TGF-β1 on regulation of gastric cancer adhesion to mesothelial cells.

Methods

Peritoneal tissues and peritoneal wash fluid were obtained for hematoxylin and eosin staining or ELISA to measure fibrosis and TGF-β1 levels, respectively. The peritoneal mesothelial cell line, HMrSV5, was used to determine the role of TGF-β1 in regulation of gastric cancer cell adhesion to mesothelial cells and expression of collagen, fibronectin, and Smad 2/3 by using adhesion assay, western blot, and RT-PCR.

Results

The data showed that TGF-β1 treatment was able to induce collagen III and fibronectin expression in the mesothelial cells, which was associated with an increased adhesion ability of gastric cancer cells, but knockdown of minimal sites of cell binding domain of extracellular matrix can partially inhibit these effects.

Conclusion

Peritoneal fibrosis induced by TGF-β1 may provide a favorable environment for the dissemination of gastric cancer.

Investigation of tumor-peritoneal interactions in the pathogenesis of peritoneal metastases using a novel ex vivo peritoneal model

BACKGROUND

Peritoneal metastasis occurs in up to 30% of patients with gastric cancer. The aim of this experimental study is to develop and validate a novel ex vivo model of the human peritoneum to better identify factors involved in the development of peritoneal metastasis in order to improve its management and prognosis.

METHODS

Peritoneal discs harvested from hernia sacs obtained at inguinal hernia surgery were suspended in media using Teflon rings. Viability of the tissue was investigated using MTS assay, light and scanning electron microscopy (LM and SEM) over 72 h. To assess validity of the model, phenotypic changes in tumor cells were investigated. Changes in matrix metalloproteinases (MMP)-2 and -9 activities in HGC and AGS gastric adenocarcinoma cells after co-culture were investigated using zymography. Modulation of tumor cell adhesion to peritoneum after exposure to heparin was assessed using a fluorometric adhesion assay. Analysis was performed using Kruskal-Wallis for multiple comparisons and Mann-Witney U for comparisons between each group.

RESULTS

MTS assay showed reduced viability after 72 h (P = 0.047, compared with 24 h). Mesothelial cell loss at 48 h was demonstrated by LM and SEM, confirming peritoneal viability for at least 24 h after tissue harvesting. Zymography confirmed increased MMP2 and -9 activities in tumor cells and peritoneal tissue during co-culture compared with controls, and heparin significantly reduced tumor cell adherence (P = 0.04), as observed in published in vivo models.

CONCLUSION

A validated complete model of peritoneum was developed that has shown potential to determine realistic mechanisms of peritoneal metastasis.

Oxidative stress-dependent increase in ICAM-1 expression promotes adhesion of colorectal and pancreatic cancers to the senescent peritoneal mesothelium

Intercellular adhesion molecule-1 (ICAM-1) has been implicated in adhesion of colorectal and pancreatic cancer cells (of the SW480 and PSN-1 line, respectively) to the peritoneal mesothelium. It has been demonstrated that ICAM-1 expression increases with senescence in some cell types, however, the significance of this phenomenon in the context of malignant dissemination remains elusive. In this report we show that the adherence of SW480 and PSN-1 cells to senescent human omentum-derived mesothelial cells (HOMCs) in vitro is greater than to early-passage cells and that the effect is mediated by ICAM-1. Senescent HOMCs display increased expression of ICAM-1 mRNA and cell surface protein. The development of this phenotype is related to increased oxidative stress in senescent cells. The augmented ICAM-1 expression in HOMCs can be reduced by culturing cells with antioxidants; in contrast, exposure of HOMCs to an oxidant, t-BHP, leads to cellular senescence and increased ICAM-1 expression. The effect is partly mediated by activation of p38 MAPK and AP-1 signaling pathways. Finally, culture of HOMCs in the presence of a strong antioxidant, PBN, significantly reduces the senescence-associated increase in SW480 and PSN-1 cancer cell binding. These results indicate that increased oxidative stress and increased expression of ICAM-1 in senescent HOMCs may facilitate peritoneal adhesion of selected colorectal and pancreatic cancers.

Intercellular adhesion molecule-1 and gelatinase expression in human peritoneal mesothelial cells during propagation in culture

Mesothelial cells are involved in a variety of biological processes, which include the formation of peritoneal adhesions. The cultures of human peritoneal mesothelial cells comprise an important tool to investigate the behavior and functions of mesothelial cells. Very little is known about the differences among mesothelial cells isolated from different sources and about the changes in specific functions as caused by cell propagation in vitro or that result from storage of cells at low temperatures. This study aims to characterize 2 particular cellular activities relevant for tissue repair, which include the expression of intercellular adhesion molecule-1 (ICAM-1) and the gelatinase activity; in addition, this study will assess the effect of hyaluronan, which is an antiadhesive agent, on these cellular activities. Viable cell lines were established from both omentum and peritoneal lavage fluid from 7 patients. Both ICAM-1 expression, which was measured by enzyme-linked immunosorbent assay (ELISA), and matrix metalloproteinase (MMP) bioactivity, which was measured by zymography, were measured in the 2nd and 4th passage; the latter also was measured after freezing and storing of cells in liquid nitrogen. The effects of interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), phorbol myristate acetate (PMA), and hyaluronan were analyzed. ICAM-1 was constitutively expressed and stimulated by IL-1beta, TNF-alpha, and PMA. All cell lines produced both MMP-2 and MMP-9. Only the latter activity was affected by TNF-alpha and, especially so, PMA. Differences were found between the 2nd and 4th passage, as well as between cells of different lineage, mostly so if the relative stimulation by the various agents was compared. The addition of sodium hyaluronate either to control cultures or to cultures together with any of the 3 stimuli examined did not significantly change either ICAM-1 expression or gelatinase activity. The freezing and storage of cells did not affect their functions. Both the human omentum and peritoneal lavage fluid are good sources to establish mesothelial cell lines, which can be propagated also after freezing without qualitative changes in their ability to express ICAM-1 and produce the gelatinases. For omental cells, a differential effect of stimulation occurs depending on whether the cells have been passaged 2 or 4 times. The presence of hyaluronan did not affect the expression of ICAM-1 or the gelatinases.

Senescent peritoneal mesothelial cells promote ovarian cancer cell adhesion: the role of oxidative stress-induced fibronectin

Adhesion of ovarian cancer cells to the peritoneal mesothelium is a key step in the malignant progression of the disease. In an in vitro study, we showed that the adherence of ovarian cancer cells (of the OVCAR-3, SKOV-3, and A2780 cell lines) to senescent human omentum-derived peritoneal mesothelial cells (HOMCs) was greater than to early passage cells. The process was mediated primarily by the increased interaction of the alpha5beta1 integrin on cancer cells with HOMC-associated fibronectin (FN). In comparison with early passage HOMCs, senescent cells exhibited increased FN mRNA expression levels and produced significantly more FN. To assess the effect of senescence-associated oxidative stress on FN release, HOMCs were rendered senescent by exposure to an oxidant, tert-butyl hydroperoxide. Treatment with tert-butyl hydroperoxide resulted in a significant increase in HOMC FN mRNA and protein expression levels. The effect of oxidative stress on FN synthesis was found to be mediated by transforming growth factor-beta1, whose signaling pathway was controlled at upstream and downstream levels by p38 MAPK. The activity of p38 MAPK increased markedly in senescent HOMCs. Treatment of HOMCs with antioxidants significantly attenuated senescence-associated increases in p38 MAPK activity, production of both transforming growth factor-beta1 and FN, and ovarian cancer cell adhesion. These data indicate that oxidative stress that accompanies senescence may increase FN production by HOMCs and thus facilitate binding and dissemination of ovarian cancer cells.

Reg IV enhances peritoneal metastasis in gastric carcinomas

OBJECTIVES

The role of Regenerating (Reg) IV on peritoneal metastasis was examined in gastric cancer using.

MATERIAL AND METHODS

Reg IV-transfected human gastric cancer cells (MKN28-R1, MKN28-R2, TMK1-R1), control transfectants (MKN28-R0, TMK1-R0), and REG4-knocked down MKN45 cells were examined in in vitro and in nude mice peritoneal metastasis models.

RESULTS AND DISCUSSION

Increase of expression and secretion of Reg IV, and levels of BCL-2, BCL-XL,survivin, phosphorylated AKT, and phosphorylated EGFR, and decrease of nitric oxide-induced apoptosis were found in Reg IV-transfectants, whereas those were abrogated in the knockdown cells. In mice models, increased number and size of peritoneal tumors and decreased apoptosis were found in Reg IV-transfectants, whereas those were abrogated by the knockdown cells. Mice survivals were worsened in Reg IV-transfectants-inoculated mice, but were improved in Reg IV-knockdown cell-inoculated mice. Levels of Reg IV protein in peritoneal lavage fluids increased in Reg IV-transfectants inoculated mice, but decreased in Reg IV-knockdown cell inoculated mice. In metastasized human gastric cancers, Reg IV positivity in peritoneum-metastasis cases was higher than those in negative cases. Reg IV was detected in peritoneal lavage fluids from human gastric cancer patients, in whose lavages keratin mRNA was detected by reverse transcriptase-polymerase chain reaction. Collectively, Reg IV might accelerate peritoneal metastasis in gastric cancer. Reg IV in lavage fluids might be a good marker for peritoneal metastasis.

Astragalus extract inhibits destruction of gastric cancer cells to mesothelial cells by anti-apoptosis

AIM: To determine the inhibitory effect of Astragalus memebranaceushas on gastric cancer cell supernatant-induced apoptosis of human peritoneal mesothelial cells.

METHODS: Human peritoneal mesothelial cell (HPMC) line HMrSV5 was co-incubated with gastric cancer cell supernatant (MKN45) and/or Astragalus memebranaceushas. Morphological changes in gastric cancer cells were observed under phase-contrast microscope. Quantitative cell damage was determined by MTT assay. Apoptosis was determined under transmission electron microscope and quantified by detecting acridine orange/ethidium bromide-stained (AO/EB) condensed nuclei under fluorescent microscope or by flow cytometry. Expressions of Bcl-2 and Bax were evaluated with immunostaining.

RESULTS: Morphological changes and exfoliation occurred and naked areas appeared in cultured HMrSV5 cells 24 h after they were treated with gastric cancer cell supernatant. Cell supernatant from MKN45 gastric cancer cells induced apoptosis of HMrSV5 cells in a time-dependent manner. Obvious morphological changes were observed in cell apoptosis, such as condensation of chromatin, nuclear fragmentations and apoptotic bodies. Astragalus memebranaceus could partly suppress these changes and regulate the expressions of Bcl-2 and Bax in HMrSV5 cells.

CONCLUSION: Gastric cancer cells induce apoptosis of HPMCs through the supernatant. Astragalus memebranaceushas inhibits this phenomenon and can be used an adjuvant chemothera-peutic agent in gastric cancer therapy.

Peritoneal minimal residual disease in colorectal cancer: mechanisms, prevention, and treatment

Roughly one in five patients with colorectal cancer develops peritoneal minimal residual disease after surgical resection, and about one in seven patients develops peritoneal carcinomatosis. By contrast with the vast body of research addressing haematogenous metastasis, little is known about the biology of peritoneal spread of colorectal cancer. The development of peritoneal carcinomatosis involves well-defined steps including cell shedding and transport, adhesion to the mesothelial layer, invasion of and proliferation into the submesothelial stroma, and potential access to the systemic circulation. In this Review, we summarise the molecular mechanisms and potential preventive measures associated with each step of the peritoneal metastatic cascade.

Tumor necrosis factor and cancer, buddies or foes?

Tumor necrosis factor (TNF) is a multifunctional cytokine that plays important roles in diverse cellular events such as cell survival, proliferation, differentiation, and death. As a pro-inflammatory cytokine, TNF is secreted by inflammatory cells, which may be involved in inflammation-associated carcinogenesis. TNF exerts its biological functions through activating distinct signaling pathways such as nuclear factor-kappaB (NF-kappaB) and c-Jun N-terminal kinase (JNK). NF-kappaB is a major cell survival signal that is anti-apoptotic, whereas sustained JNK activation contributes to cell death. The crosstalk between the NF-kappaB and JNK is involved in determining cellular outcomes in response to TNF. In regard to cancer, TNF is a double-dealer. On one hand, TNF could be an endogenous tumor promoter, because TNF stimulates the growth, proliferation, invasion and metastasis, and tumor angiogenesis of cancer cells. On the other hand, TNF could be a cancer killer. The property of TNF in inducing cancer cell death renders it a potential cancer therapeutic, although much work is needed to reduce its toxicity for systematic TNF administration. Recent studies have focused on sensitizing cancer cells to TNF-induced apoptosis through inhibiting survival signals such as NF-kappaB, by combined therapy. In this article we provide an overview of the roles of TNF-induced signaling pathways in cancer biology with specific emphasis on carcinogenesis and cancer therapy.

Clinical significance of telomerase activity in peritoneal disseminated cells: gastrointestinal cancers

Early detection and accurate staging of gastrointestinal (GI) cancers are difficult. The aim of this study was to evaluate whether telomerase activity (TA) in exfoliated/disseminated epithelial cells could be used as a reliable marker for GI cancers. TA was evaluated with the real-time RTQ-TRAP in immunomagnetically sorted peritoneal epithelial cells from 60 patients undergoing surgical treatment. Thirty-two patients were clinically diagnosed with a variety of GI cancers: 1 had premalignant disease, 2 had history of GI cancers, and 25 patients were clinically negative for cancer. Here we report that all types and all cases of gastrointestinal cancers were telomerase positive, thereby demonstrating 100% sensitivity for cancer. Eighteen of 25 nonmalignant cases had undetectable levels of TA, 2 had low, and 5 of 25 expressed high TA levels. Because normal epithelial cells usually have low TA and a lesser tendency to exfoliate compared with cancer cells, it is of great importance to have close follow-up for these patients to exclude possible malignant disease. We conclude that RTQ-TRAP assessment of TA in immunomagnetically sorted peritoneal epithelial cells has 100% sensitivity and 100% negative predictive value for GI cancers, and therefore, can be considered as a valuable tool and useful addition to current standard diagnostic methods. Clinical significance of unusually high telomerase activity in some clinically negative for cancer cases requires further study.

Instillation of taurolidine/heparin after laparotomy reduces intraperitoneal tumour growth in a colon cancer rat model

OBJECTIVE

To investigate whether irrigation of the abdominal cavity after laparotomy for caecum resection with taurolidine/heparin or adhesion prophylactic substances reduces intraperitoneal tumour growth or the local recurrence rate in a colon carcinoma rat model.

METHODS

60 BDIX rats underwent caecum resection after intraperitoneal inoculation of 1 x 10(4) colon carcinoma cells (DHD/K12/TRb). Intergel, Interceed, taurolidine/heparin or NaCl 0.9% were intraperitoneally applied after randomisation. Finally, the total number and total weight of intraperitoneal metastases were determined as well as the adhesion score according to Moreno. Metastatic tissue was examined histologically and immunohistochemically (E-cadherin, CD44, beta(1)-integrin).

RESULTS

Taurolidine/heparin significantly reduced not only the total number (3 vs. 11 in the control group) but also the total weight (65 vs. 330 mg) of intraperitoneal metastases in comparison to the control group (p = 0.003 and p = 0.005). E-Cadherin expression in the metastatic tissue of animals treated with taurolidine/heparin was significantly decreased (p = 0.016).

CONCLUSION

Taurolidine/heparin effectively reduces intraperitoneal tumour growth when used as an intraoperative lavage. These results represent a good rationale for intraoperative adjuvant irrigation with taurolidine/heparin during resection of colon cancer.