Identification of cancer stem cell markers in human malignant mesothelioma cells

Malignant mesothelioma (MM) is an aggressive and therapy-resistant neoplasm arising from the pleural mesothelial cells and usually associated with long-term asbestos exposure. Recent studies suggest that tumors contain cancer stem cells (CSCs) and their stem cell characteristics are thought to confer therapy-resistance. However, whether MM cell has any stem cell characteristics is not known. To understand the molecular basis of MM, we first performed serial transplantation of surgical samples into NOD/SCID mice and established new cell lines. Next, we performed marker analysis of the MM cell lines and found that many of them contain SP cells and expressed several putative CSC markers such as CD9, CD24, and CD26. Interestingly, expression of CD26 closely correlated with that of CD24 in some cases. Sorting and culture assay revealed that SP and CD24⁺ cells proliferated by asymmetric cell division-like manner. In addition, CD9⁺ and CD24⁺ cells have higher potential to generate spheroid colony than negative cells in the stem cell medium. Moreover, these marker-positive cells have clear tendency to generate larger tumors in mouse transplantation assay. Taken together, our data suggest that SP, CD9, CD24, and CD26 are CSC markers of MM and could be used as novel therapeutic targets.     

Neurotensin expression and outcome of malignant pleural mesothelioma

Malignant pleural mesothelioma is a frequently fatal disease and the impact of available treatments is globally poor. Identification of new prognostic factors would help in the understanding of disease progression and, possibly, patient management. Here, we evaluate the prognostic impact of the neurotensin (NTS) and its cognate receptor (NTSR1) known for mediating cellular proliferation, survival, invasiveness, and mobility. We studied a series of 52 consecutive patients with epithelioid malignant mesothelioma undergoing management with curative intent, by immunohistochemistry for the expression of NTS and NTSR1. Specimens were scored as 0, 1, or 2 for less than 10%, between 10 and 50%, or more than 50% of NTS positive staining in tumor cells, respectively. Immunohistochemistry revealed that NTS and NTSR1 expression was found in 71.1% and 90.4% of malignant mesotheliomas, respectively. Using univariate analysis, expression of NTS was significantly (p = 0.015) related with a poor prognosis, with median survivals of 11.0 months, 18.4 months, and 29.8 months in patients showing expression scored as 2, 1, and 0, respectively. Multivariate analysis showed that expression of NTS (p = 0.007) and non-surgical therapy (p = 0.004) were independent predictors of poor prognosis. In order to evaluate the role of NTS/NTSR1 complex in mesothelioma progression, in vitro cell invasion assays and wound healing were performed on the mesothelioma cell line, MSTO-211H, and showed that inhibition of the NTS system resulted in a significant reduction of both migration and collagen invasion of mesothelioma cells. The expression of NTS is identified as a prognostic marker in patients with malignant pleural mesothelioma (Patent EP 08305971.7).     

Epidemiology of malignant peritoneal mesothelioma: A population-based study

BackgroundMalignant peritoneal mesothelioma (MPeM) is a rare cancer of the mesothelial cells in the peritoneum with poor prognosis. Earlier reports from other countries indicate an incidence of 0.2–3 new cases per million per year. No previous studies have examined the national epidemiology of MPeM in Nordic countries. This study aimed to clarify the epidemiology of MPeM in Finland over a 12-year period.MethodsThe data consisted of cancer notifications, laboratory notifications, and death certificate information in the Finnish Cancer Registry (FCR) and Statistics Finland (SF) of all MPeM patients from 2000 to 2012 in Finland. We also collected data on occupational disease compensations from the Workers’ Compensation Center (WCC) of Finland. Any missing information was collected from the respective patient’s file of every patient obtained from health institutions that had treated the patients.ResultsBetween January 1, 2000 and December 31, 2012, 90 new MPeM cases (56 males, 34 females) occurred in Finland. Median annual incidence was four new cases, which corresponded to 0.74 new cases per million per year. MPeM was deemed an occupational disease in 21 patients (23.3%). 71 patients (78.9%) of whom had a known cause of death, with a median survival of 4 months. The number of deaths linked to other disease than mesothelioma was 28/74 (37.8%).ConclusionsOur study indicates that MPeM in Finland is rare and fatal, which is in accordance with previous reports from other countries. MPeM is also a fatal disease, since most of the patients died due to MPeM.     

Peritoneal mesothelioma mortality in Italy: Spatial analysis and search for asbestos exposure sources

BackgroundThis study is part of a national plan of epidemiological surveillance of malignant mesothelioma (MM) mortality in Italy. The paper shows the results of malignant peritoneal mesothelioma (MPeM) mortality study in Italian Regions and municipalities.MethodsNational Bureau of Statistics data for MPeM municipal mortality (ICD-10, Code C45.1) were analyzed in the time-window 2003–2014: mortality standardized rates (reference Italian population, census 2011), temporal trends of the annual national rates, Standardized Mortality Ratios and a municipal clustering analysis were performed.Results747 deaths for MPeM were recorded (0.10/100,000): 464 in men (0.14/100,000) and in 283 women (0.07/100,000). No significant MPeM mortality temporal trend was found.Seventeen municipalities showed excesses of mortality for MPeM in at least one gender and/or overall population.Four clusters in male population, and one in women were identified.ConclusionsThe study identifies some areas where remediation activities and/or health care actions may be warranted.     

Radiotherapy applications of patients with malignant mesothelioma: A single center experience

Background

In the management of malignant pleural mesothelioma, radiotherapy has been used for the purpose of prophylaxis to reduce the incidence of recurrence at surgical insertion sites or palliate the symptoms.

Aim

The purpose of the study was to evaluate the techniques and effectiveness of radiotherapy in malignant pleural mesothelioma.

Materials and methods

Forty-four (18 female, 26 male) patients diagnosed with malignant pleural mesothelioma were retrospectively evaluated. All patients had surgery or thoracoscopic biopsy for diagnosis, staging or treatment and all received palliative or prophylactic radiotherapy. Fifty-seven percent of the patients received chemotherapy.

Results

Prophylactic radiation was applied to 27 patients with 4–15 MeV electron energies. The median radiotherapy dose was 30 Gy with 3 Gy daily fraction dose. During treatment, 12 patients had grade 1 erythema according to the RTOG scale. In 3 (12%) patients, a local failure at treatment field was observed. Palliative radiotherapy was applied to 17 patients for pain palliation. The median radiation dose was 40 Gy with 2 Gy daily fraction dose by using 6–18 MV photon and/or 4–12 MeV electron energies. Two patients had grade 1 erythema and one patient had grade 2 odynophagy according to the RTOG scale. For 10 (59%) patients, palliation of chest pain was delivered. No late toxicity was observed for all cases.

Conclusion

Our experience showed that prophylactic and palliative radiotherapy are effective and safe therapy modalities in malignant pleural mesothelioma in preventing seeding metastasis at intervention sites or relieving pain. Prospective randomized studies are still needed to determine the benefits of radiotherapy application and to indicate optimum dose schemes.     

The impact of malignant pleural mesothelioma throughout Italy in the years 1995–2002: a geo-referenced study relating death rate to population distribution

We analyzed the official yearly mortality data due to malignant pleural mesothelioma (MPM) from 1995 to 2002 in all 107 Italian provinces, and we related them to provincial resident population in the same years. The resulting ratios are displayed as geographically referenced maps, which enhance the visual impact on how that fatal disease distributes over the country. The following results are statistically meaningful: (1) internal migration changed the Italian population distribution, with major increases in regions Lombardy, Trentino–Alto Adige, Veneto, and Emilia–Romagna, and moderate decreases in Piemonte, Liguria, and Friuli–Venezia Giulia. (2) MPM mortality is increasing overall, with five provinces largely exceeding the average Italian rate: Alessandria (Piemonte), Genoa and La Spezia (Liguria), and Gorizia and Trieste (Friuli–Venezia Giulia). (3) There is a substantial mortality rate increase in the same provinces which shows decreasing population. Results are discussed with reference to well-known cases of asbestos-polluted sites such as Balangero and Casale Monferrato (Piemonte), Genoa and La Spezia (Liguria), and Monfalcone and Trieste (Friuli–Venezia Giulia). General unquestionable conclusions are (a) occupational exposure, especially working conditions, increases MPM mortality; (b) non-occupational exposure data are scattered, as are male versus female data, and cannot be dealt with statistically on a nation-wide scale; (c) natural environmental exposure may contribute to MPM mortality, but its effect is still statistically minor. The MPM mortality apex is currently reached at Trieste, a province free of asbestos minerals occurring in their natural setting, but where MPM affects workers in the marine industry strongly who operated in contact with insulating outfits. Information on content and type of amphibole present in the asbestos materials used for industrial applications is scattered and generally scarce, thus making the evaluation of the amphibole versus chrysotile relative impact on MPM mortality rates statistically unsound.     

Incidence and survival of peritoneal malignant mesothelioma between 1989 and 2015: A population-based study

BackgroundPeritoneal malignant mesothelioma is a rare disease for which few population-based studies are available. The aim of this study was to describe the evolution of the incidence and survival of peritoneal malignant mesothelioma in France between 1989 and 2015, using data derived from the French network of cancer registries.MethodsAge world-standardized incidence rates and overall survival were calculated using data from 16 French cancer registries. Log-linear Poisson regression analysis was used to estimate the average annual percentage change in incidence rates. Overall survival was performed using age-adjusted Cox proportional hazards model.ResultsIn French men, the incidence has increased quietly over the reporting period from 0.07 to 0.10 with a maximum of 0.16 per 100,000 persons-years in 2001–2003. For women, the increase in incidence has been lower than for men over the period 1989–2015, ranging from 0.04 to 0.11. A better prognosis was associated with a diagnosis made after 2000 (HR = 1.76; p = 0.013), the epithelioid histological type (p = 0.003), and the fact of being a woman, which has a 5-year risk of death half that of men (HR = 0.55; p = 0.001), regardless of age, diagnosis period or histology.ConclusionOur results are similar to those currently available for other countries. In France, peritoneal mesothelioma remains a rare and fatal cancer with a small increase in the incidence rate since 1989 and a median survival of 1 year; it seemed to develop equally in women and men over this period of time.     

Zebularine exerts its antiproliferative activity through S phase delay and cell death in human malignant mesothelioma cells

Malignant mesothelioma is an asbestos-related aggressive tumor and current therapy remains ineffective. Zebularine as a DNA methyltransferase (DNMT) inhibitor has an anti-tumor effect in several human cancer cells. The aim of the present study was to investigate whether zebularine could induce antiproliferative effect in human malignant mesothelioma cells. Zebularine induced cell growth inhibition in a dose-dependent manner. In addition, zebularine dose-dependently decreased expression of DNMT1 in all malignant mesothelioma cells tested. Cell cycle analysis indicated that zebularine induced S phase delay. Zebularine also induced cell death in malignant mesothelioma cells. In contrast, zebularine did not induce cell growth inhibition and cell death in human normal fibroblast cells. These results suggest that zebularine has a potential for the treatment of malignant mesothelioma by inhibiting cell growth and inducing cell death.     

Establishment of permanent cell lines purified from human mesothelioma: morphological aspects,new marker expression and karyotypic analysis

This study reports the establishment of three major subtypes of human mesothelioma cells in tissue culture, i.e. the epithelioid, sarcomatoid and biphasic forms, and compares their phenotypic and biological characteristics. Primary cells isolated from biopsies or pleural exudates were subcultured for over 50 passages. We evaluated immunoreactivity using various mesothelial markers related to histological patterns of these cell lines. For epithelioid cells, calretinin and cytokeratin were found to be useful and easily interpretable markers as for control mesothelial cells. The biphasic form was only partially positive and the sarcomatoid type negative. Vimentin was expressed by all cell lines. BerEP4, a specific marker for adenocarcinoma, was negative. Interestingly, while the macrophage marker CD14 was negative, immunoreactivity for a mature macrophage marker (CD68) was expressed by all cell types, suggesting that this marker might constitute an additional tool useful in the differential diagnosis of mesothelioma. At the ultrastructural level, a cell surface rich in microvilli confirmed their mesothelial origin. PCR analysis revealed that none of the cell lines contained SV40 DNA. Karyotypic analyses showed more complex abnormalities in the epithelioid subtype than in the sarcomatoid form. These cell lines may be useful in the study of cellular, molecular and genetic aspects of the disease.     

Lung tissue engineering: An update

Pulmonary disease is a worldwide public health problem that reduces the life quality and increases the need for hospital admissions as well as the risk of premature death. A common problem is the significant shortage of lungs for transplantation as well as patients must also take immunosuppressive drugs for the rest of their lives to keep the immune system from attacking transplanted organs. Recently, a new strategy has been proposed in the cellular engineering of lung tissue as decellularization approaches. The main components for the lung tissue engineering are: (1) A suitable biological or synthetic three-dimensional (3D) scaffold, (2) source of stem cells or cells, (3) growth factors required to drive cell differentiation and proliferation, and (4) bioreactor, a system that supports a 3D composite biologically active. Although a number of synthetic as well biological 3D scaffold suggested for lung tissue engineering, the current favorite scaffold is decellularized extracellular matrix scaffold. There are a large number of commercial and academic made bioreactors, the favor has been, the one easy to sterilize, physiologically stimuli and support active cell growth as well as clinically translational. The challenges would be to develop a functional lung will depend on the endothelialized microvascular network and alveolar–capillary surface area to exchange gas. A critical review of the each components of lung tissue engineering is presented, following an appraisal of the literature in the last 5 years. This is a multibillion dollar industry and consider unmet clinical need.     

Emerging concept of cancer as a stem cell disorder

Evidence has accumulated that malignancy arises from maturation arrest of stem cells — rather than the dedifferentiation of somatic cells. To support this notion, stem cells in contrast to somatic cells are long lived cells and thus may become the subject of accumulating mutations that are crucial for the initiation/progression of cancer. More importantly they may maintain these mutations and pass them to daughter stem cells. Cancer stem cells (CSC) that derive from transformed normal stem cells (NSC) are responsible not only for tumor initiation, but also for its re-growth and metastasis. Accumulating evidence also indicates that adult tissues may contain a population of very small embryonic like (VSEL) stem cells that may give rise to some very immature tumors e.g., pediatric sarcomas. Similar molecular mechanisms operating in NSC and CSC regulate resistance to radio-chemotherapy and promote migration/metastasis. Thus, by studying the biology of NSC we can learn more about cancer.     

MicroRNA: A new player in response to therapy for colorectal cancer

Colorectal cancer (CRC) is one of the important malignancies that result in cancer-related deaths worldwide. Multiple lines of evidence have indicated that different responses to therapy in CRC cells led to the failure of the current therapies. Hence, identification of the underlying cellular and molecular pathways involved in the emergence of different responses from CRC cells could contribute to finding and designing new therapeutic platforms to overcome the present limitations. Among the various targets involved in CRC pathogenesis, microRNAs (miRNAs) have key roles in many signaling pathways that are associated with the initiation and progression of CRC. Increasing evidence has confirmed that miRNAs as epigenetic regulators could play critical roles in the response (resistance or sensitivity) to therapy. Cancer stem cells are well-known players in resistance to therapy in CRC. They have been shown to play significant roles via inhibition and activation of many miRNA networks. Hence, miRNAs could be involved in the resistance and sensitivity of therapy in CRC cells via affecting different mechanisms, such as activation of cancer stem cells. Here, we summarized the role of various miRNAs in response to therapy of CRC cells. Moreover, we highlighted the roles of these molecules in the function of cancer stem cells, which are known as important players in the resistance to therapy in CRC.     

miR-888 in MCF-7 Side Population Sphere Cells Directly Targets E-cadherin

Side population （SP） cells are a small subset of cells isolated from a cultured cancer cell line that exhibit characteristics similar to those of cancer stem cells （CSCs）, such as high metastatic and tumorigenic potential. The molecular mechanisms that give rise to the malignant properties of SP cells are not clear. We isolated SP cells from the MCF-7 breast cancer cell line and profiled microRNA （miRNA） expression patterns between SP cell-derived spheroids and non-SP cells. SP spheroids were found to possess 42 up-regulated miRNAs and 27 down-regulated ones （above 5-fold changes）. One of the up-regulated miRNAs, miR-888 computationally predicted to participate in the adherens junction （AJ） pathway, was investigated. Over-expression of miR-888 in MCF-7 cells reduced the mRNA levels of all four AJ pathway genes （E-cadherin, ACTG1, PTPRTand CDC42） that were selected for testing, whereas knocking down miR-888 reversed the trends. Western blot and flow cytometric quantitation of the membrane E-cadherin levels showed the same trend of change under these treatments. Luciferase reporter assay showed E-cadherin is a direct target of miR-888. As a potential role in intercellular adhesiveness and maintenance of malignant tissue architecture, the results indicate that miR-888 is a repressor of the AJ pathway in MCF-7 cells and that up-regulation of miR-888 contributes to aggressiveness in MCF-7 SP cells.     

Convergence of normal stem cell and cancer stem cell developmental stage: Implication for differential therapies

Increased evidence shows that normal stem cells may contribute to cancer development and progression by acting as cancer-initiating cells through their interactions with abnormal environmental elements.We postulate that normal stem cells and cancer stem cells (CSC) possess similar mechanisms of self-renewal and differentiation.CSC can be the key to the elaboration of anti-cancer-based therapy.In this article,we focus on a controversial new theme relating to CSC.Tumorigenesis may have a critical stage characterized as a "therapeutic window",which can be identified by asso-ciation of molecular,biochemical and biological events.Identifying such a stage can allow the production of more effective therapies (e.g.manipulated stem cells) to treat several cancers.More importantly,confirming the existence of a similar therapeutic window during the conversion of normal stem cells to malignant CSC may lead to targeted therapy specifically against CSC.This conversion information may be derived from investigating the biological behaviour of both normal stem cells and cancerous stem cells.Currently,there is little knowledge about the cellular and molecular mechanisms that govern the initiation and maintenance of CSC.Studies on co-evolution and interdependence of cancer with normal tissues may lead to a useful treatment paradigm of cancer.The crosstalk between normal stem cells and cancer formation may converge developmental stages of different types of stem cells (e.g.normal stem cells,CSC and embryonic stem cells).The differential studies of the convergence may result in novel therapies for treating cancers.     

DNA damage responses in cancer stem cells: Implications for cancer therapeutic strategies

The identification of cancer stem cells(CSCs) that are responsible for tumor initiation, growth, metastasis, and therapeutic resistance might lead to a new thinking on cancer treatments. Similar to stem cells,CSCs also display high resistance to radiotherapy and chemotherapy with genotoxic agents. Thus, conventional therapy may shrink the tumor volume but cannot eliminate cancer. Eradiation of CSCs represents a novel therapeutic strategy. CSCs possess a highly efficient DNA damage response(DDR) system, which is considered as a contributor to the resistance of these cells from exposures to DNA damaging agents. Targeting of enhanced DDR in CSCs is thus proposed to facilitate the eradication of CSCs by conventional therapeutics. To achieve this aim, a better understanding of the cellular responses to DNA damage in CSCs is needed. In addition to the protein kinases and enzymes that are involved in DDR, other processes that affect the DDR including chromatin remodeling should also be explored.     

MicroRNA expression profile of colon cancer stem-like cells in HT29 adenocarcinoma cell line

Increasing evidence has suggested cancer stem cells (CSCs) are considered to be responsible for cancer formation, recurrence, and metastasis. Recently, many studies have also revealed that microRNAs (miRNAs) strongly implicate in regulating self renewal and tumorigenicity of CSCs in human cancers. However, with respect to colon cancer, the role of miRNAs in stemness maintenance and tumorigenicity of CSCs still remains to be unknown. In the present study, we isolated a population of colon CSCs expressing a CD133 surface phenotype from human HT29 colonic adenocarcinoma cell line by Flow Cytometry Cell Sorting. The CD133⁺ cells possess a greater tumor sphere-forming efficiency in vitro and higher tumorigenic potential in vivo. Furthermore, the CD133⁺ cells are endowed with stem/progenitor cells-like property including expression of “stemness” genes involved in Wnt2, BMI1, Oct3/4, Notch1, C-myc and other genes as well as self-renewal and differentiation capacity. Moreover, we investigated the miRNA expression profile of colon CSCs using miRNA array. Consequently, we identified a colon CSCs miRNA signature comprising 11 overexpressed and 8 underexpressed miRNAs, such as miR-429, miR-155, and miR-320d, some of which may be involved in regulation of stem cell differentiation. Our results suggest that miRNAs might play important roles in stemness maintenance of colon CSCs, and analysis of specific miRNA expression signatures may contribute to potential cancer therapy.     

Proteomic study of malignant pleural mesothelioma by laser microdissection and two-dimensional difference gel electrophoresis identified cathepsin D as a novel candidate for a differential diagnosis biomarker

To investigate the proteomic background of malignancies of the pleura, we examined and compared the proteomic profile of malignant pleural mesothelioma (MPM)(10 cases), lung adenocarcinoma (11 cases), squamous cell carcinoma of the lung (13 cases), pleomorphic carcinoma of the lung (3 cases) and synovial sarcoma (6 cases). Cellular proteins were extracted from specific populations of tumor cells recovered by laser microdissection. The extracted proteins were labeled with CyDye DIGE Fluor saturation dyes and subjected to two-dimensional difference gel electrophoresis (2D-DIGE) using a large format electrophoresis device. Among 3875 protein spots observed, the intensity of 332 was significantly different (Wilcoxon p value less than 0.05) and with more than two-fold inter-sample-group average difference between the different histology groups. Among these 332, 282 were annotated by LC-MS/MS and included known biomarker proteins for MPM, such as calretinin, as well as proteins previously uncharacterized in MPM. Tissue microarray immunohistochemistry revealed that the expression of cathepsin D was lower in MPM than in lung adenocarcinoma (15% vs. 44% of cases respectively in immunohistochemistry). In conclusion, we examined the protein expression profile of MPM and other lung malignancies, and identified cathepsin D to distinguish MPM from most popular lung cancer such as lung adenocarcinoma.     

Patho- and immunobiology of malignant mesothelioma: characterisation of tumour infiltrating leucocytes and cytokine production in a murine model

Malignant mesothelioma (MM) is an aggressive, uniformly fatal serosal tumour, usually associated with asbestos exposure, for which there currently is no effective treatment. In order to gain insight into the mechanism(s) whereby MM might escape immune surveillance, a murine model for MM was used (a) to characterise the tumour-infiltrating lymphocytes (TIL) and macrophages (TIM) phenotypically, (b) to examine systemic immune recognition of MM, and (c) to examine the possible influence of tumour-derived cytokines on systemic and local pathobiological manifestations of MM. A profound down-regulation of lymphocyte surface markers, known to be infolved in T cell activation, was found in TIL. Likewise, although TIM were present in large numbers, their expression of MHC class II antigen and integrins was weak or absent, suggestive of altered functional activity. Significant amounts of cytokines, in particular transforming growth factor , interleukin-6 (IL-6), IL-1 and tumour necrosis factor were produced during the course of MM tumour development-directly by the MM cells and/or indirectly in response to tumour growth. These factors may contribute both to derangement of antitumour effector mechanisms and to the clinical and pathological manifestations of the disease.