Malignant mesothelioma 2008

Establishment and validation of nomograms to predict survival probability of advanced malignant pleural mesothelioma based on the SEER database and a Chinese medical institution

Objective

The purpose of this study was to build nomograms for predicting the survival of individual advanced pleural mesothelioma (MPM) patients using the Surveillance, Epidemiology, and End Results (SEER) database.

Methods

The 1251 patients enrolled from the SEER database were randomized (in a 7:3 ratio) to a training cohort and an internal validation cohort. Eighty patients were enrolled from the Harbin Medical University Cancer Hospital as the external validation cohort. Nomograms were constructed from variables screened by univariate or multivariate Cox regression analyses and evaluated by consistency indices (C-index), calibration plots, and receiver operating characteristic (ROC) curves. Patients from the SEER database who received chemotherapy alone and chemoradiotherapy were statistically paired using propensity score matching of the two groups and performed subgroup analysis in the screened variables.

Results

The nomograms are well-structured and well-validated prognostic maps constructed from four variables: gender, histology, AJCC stage, and treatment. All individuals were allocated into high-risk versus low-risk groups based on the median risk score of the training cohort, with the high-risk group having worse OS and CSS in all three cohorts (P<0.05). The outcomes of the subgroup analysis indicated that the advanced MPM patients receiving chemotherapy with or without local radiotherapy do not affect OS or CSS.

Conclusion

The accurate nomograms to predict the survival of patients with advanced MPM were built and validated based on an analysis of the SEER database with an external validation cohort. The study suggests that the additional local radiotherapy to chemotherapy does not increase the survival benefit of patients.

Ponatinib is a potential therapeutic approach for malignant pleural mesothelioma

PURPOSE

Malignant pleural mesothelioma (MPM) is a rare and deadly malignancy. Current MPM therapies remain inadequate, and outcomes are often disappointing. New meaningful therapeutic approaches are urgently needed. Accumulating evidence indicates that the cAbl pathway promotes various tumor-stimulating processes in MPM. In this study, we sought to determine ponatinib's potential utility, a clinically approved and potent cAbl inhibitor, in MPM treatment.

MATERIAL AND METHODS

Four MPM lines (MSTO211H, H28, H2452, H2052) were treated with ponatinib in vitro, and their growth was assessed. Scratch wound assay was used to investigate the ponatinib effect on cell migration. The expression levels of pAbl and its downstream effectors pCrkL, pAKT, and pSTAT5 were characterized. The in vivo ponatinib effect was evaluated in human MPM cells derived tumor model.

RESULTS

In all four MPM lines, significant expression levels of phosphorylated cAbl/Arg and pCrkl were observed. Differentially but strongly, ponatinib inhibited the in vitro cell growth and migration of all four MPM line. Western blot analysis showed that the activation of Abl signaling was blocked in the ponatinib-treated MMP lines. In keeping, the cellular levels of pAbl and its downstream effector pCrkL, pAKT, and pSTAT5 were markedly decrease following ponatinib treatment. Moreover, ponatinib treatment amplified the levels of γH2AX in cells denoting increased double-strand DNA breaks levels. Notably, ponatinib treatment reduced in vivo tumor growth and reduced pCrkl and pSTAT5 levels in tumor samples.

CONCLUSION

Ponatinib may offer a new therapeutic strategy for MPM patients based on cAbl signaling pathway inhibition.

ALPPL2 Is a Highly Specific and Targetable Tumor Cell Surface Antigen

Identification of tumor-specific cell surface antigens has proven challenging, as the vast majority of tumor-associated antigens are also expressed in normal tissues. In mesothelioma, we identified a highly specific tumor cell surface antigen that can be targeted for therapy development. Mesothelioma is caused by malignant transformation of the mesothelium, is incurable, and can be categorized into three histologic subtypes: epithelioid, biphasic, and sarcomatoid. To identity novel mesothelioma cell surface antigens with broad subtype coverage and high tissue specificity, we have previously selected phage antibody display libraries on live mesothelioma cells and tissues following counterselection on normal cells and identified a panel of human antibodies that bind all subtypes of mesothelioma, but not normal mesothelium. One of the antibodies, M25, showed high specificity against an antigen we identify here as ALPPL2. IHC on normal human tissues found that ALPPL2 is expressed only on placental trophoblasts, but not on any other normal tissues. This significant tissue specificity and broad tumor type coverage suggest that ALPPL2 could be an excellent cell surface target for therapeutic development against mesothelioma. To evaluate therapeutic potential of ALPPL2 targeting, an ALPPL2-targeted antibody-drug conjugate was developed and demonstrated potent and specific tumor killing in vitro and in vivo against both epithelioid and sarcomatoid mesothelioma. Thus, ALPPL2 belongs to a rare class of cell surface antigens classified as truly tumor specific and is well suited for therapy development against ALPPL2-expressing tumors. SIGNIFICANCE: These findings identify ALPP2 as a true tumor-specific cell surface antigen whose tissue specificity enables the development of novel therapies.

Mesothelioma Biomarkers: Discovery in Search of Validation

Malignant pleural mesothelioma (MPM) is an asbestos-related neoplasm that can only be treated successfully when correctly diagnosed and treated early. The asbestos-exposed population is a high-risk group that could benefit from sensitive and specific blood- or tissue-based biomarkers. We review recent work with biomarker development in MPM and literature of the last 20 years on the most promising blood- and tissue-based biomarkers. Proteomic, genomic, and epigenomic platforms are covered. SMRP is the only validated blood-based biomarker with diagnostic, monitoring and prognostic value. To strengthen development and testing of MPM biomarkers, cohorts for validation must be established by enlisting worldwide collaborations.

Mesothelioma Biomarkers: A Review Highlighting Contributions from the Early Detection Research Network

Malignant pleural mesothelioma (MPM) is an asbestos-related neoplasm, which can be treated successfully only if correctly diagnosed and treated in early stages. The asbestos-exposed population serves as a high-risk group that could benefit from sensitive and specific blood- or tissue-based biomarkers. This review details the recent work with biomarker development in MPM and the contributions of the NCI Early Detection Research Network Biomarker Developmental Laboratory of NYU Langone Medical Center. The literature of the last 20 years was reviewed to comment on the most promising of the blood- and tissue-based biomarkers. Proteomic, genomic, and epigenomic platforms as well as novel studies such as "breath testing" are covered. Soluble mesothelin-related proteins (SMRP) have been characterized extensively and constitute an FDA-approved biomarker in plasma with diagnostic, monitoring, and prognostic value in MPM. Osteopontin is found to be a valuable prognostic biomarker for MPM, while its utility in diagnosis is slightly lower. Other biomarkers, such as calretinin, fibulin 3, and High-Mobility Group Box 1 (HMGB1), remain under study and need international validation trials with large cohorts of cases and controls to demonstrate any utility. The EDRN has played a key role in the development and testing of MPM biomarkers by enlisting collaborations all over the world. A comprehensive understanding of previously investigated biomarkers and their utility in screening and early diagnosis of MPM will provide guidance for further future research.See all articles in this CEBP Focus section, "NCI Early Detection Research Network: Making Cancer Detection Possible."

Curcumin as an Anticancer Agent in Malignant Mesothelioma: A Review

Malignant mesothelioma is an infrequent tumor that initiates from the mesothelial cells lining of body cavities. The great majority of mesotheliomas originate in the pleural cavity, while the remaining cases initiate in the peritoneal cavity, in the pericardial cavity or on the tunica vaginalis. Usually, mesotheliomas grow in a diffuse pattern and tend to enclose and compress the organs in the various body cavities. Mesothelioma incidence is increasing worldwide and still today, the prognosis is very poor, with a reported median survival of approximately one year from presentation. Thus, the development of alternative and more effective therapies is currently an urgent requirement. The aim of this review article was to describe recent findings about the anti-cancer activity of curcumin and some of its derivatives on mesotheliomas. The potential clinical implications of these findings are discussed.

Curcumin C3 complex®/Bioperine® has antineoplastic activity in mesothelioma: an in vitro and in vivo analysis

BACKGROUND

A major limitation in the treatment for malignant mesothelioma is related to serious side effects caused by chemotherapeutics and to the development of cancer-resistance. Advances in cancer therapies have been reached thanks to the introduction of alternative approaches, such as the use of phytochemicals. Curcumin-C3complex®/Bioperine® is a commercially standardized extract containing a ratio-defined mixture of three curcuminoids and piperine that greatly increase its bioavailability. Interestingly, the anticancer effect of this formulation has been described in different studies and several clinical trials have been started, but to our knowledge none refers to human mesothelioma.

METHODS

Curcumin-C3complex®/Bioperine® anticancer effect was evaluated in vitro in different human mesothelioma cell lines analysing cell proliferation, colony-forming assay, wound healing assays, invasion assay and FACS analysis. In vivo anticancer properties were analysed in a mesothelioma xenograft mouse model in CD1 Nude mice.

RESULTS

Curcumin-C3complex®/Bioperine® in vitro induced growth inhibition in all mesothelioma cell lines analysed in a dose- and time-depended manner and reduced self-renewal cell migration and cell invasive ability. Cell death was due to apoptosis. The analysis of the molecular signalling pathway suggested that intrinsic apoptotic pathway is activated by this treatment. This treatment in vivo delayed the growth of the ectopic tumours in a mesothelioma xenograft mouse model.

CONCLUSIONS

Curcumin-C3complex®/Bioperine® treatment strongly reduces in vitro tumorigenic properties of mesothelioma cells by impairing cellular self-renewal ability, proliferative cell rate and cell migration and delays tumor growth in xenograft mouse model by reducing angiogenesis and increasing apoptosis. Considering that curcumin in vivo synergizes drug effects, its administration to treatment regimen may help to enhance drug therapeutic efficacy in mesothelioma. Our results suggest that implementation of standard pharmacological therapies with novel compounds may pave the way to develop alternative approaches to mesothelioma.

Biomarkers for malignant pleural mesothelioma: a meta-analysis

Malignant pleural mesothelioma (MPM) is a rare but aggressive cancer, and early detection is associated with better survival. Mesothelin, fibulin-3 and osteopontin have been suggested as screening biomarkers. The study conducted a meta-analysis of the mean differences of mesothelin, osteopontin and fibulin-3 in blood and pleural samples. PubMed searches were conducted for studies that measured levels of mesothelin, osteopontin and fibulin-3 in participants with MPM compared with malignancy, benign lung disease or healthy participants. Thirty-two studies with mesothelin levels, 12 studies with osteopontin levels and 9 studies with fibulin-3 levels were included in the meta-analysis. Statistically significant mean differences were seen between MPM patients and all other comparison groups for mesothelin blood and pleural levels. Statistically significant differences in blood osteopontin levels were seen between participants with benign lung disease and healthy participants compared with participants with MPM, but not when comparing participants with cancer with MPM participants. There were not enough studies that reported osteopontin levels in pleural fluid to complete a meta-analysis. Statistically significant differences were seen in both blood and pleural levels of fibulin-3 in MPM patients compared with all other groups. On the basis of these results, mesothelin and fibulin-3 levels appear to be significantly lower in all control groups compared with those with MPM, making them good candidates for screening biomarkers. Osteopontin may be a useful biomarker for screening healthy individuals or those with benign lung disease but would not be useful for screening patients with malignancies.

Intrapleural Adenoviral-mediated Endothelial Cell Protein C Receptor Gene Transfer Suppresses the Progression of Malignant Pleural Mesothelioma in a Mouse Model

Malignant pleural mesothelioma (MPM) is an aggressive thoracic cancer with a high mortality rate as it responds poorly to standard therapeutic interventions. Our recent studies showed that expression of endothelial cell protein C receptor (EPCR) in MPM cells suppresses tumorigenicity. The present study was aimed to investigate the mechanism by which EPCR suppresses MPM tumor growth and evaluate whether EPCR gene therapy could suppress the progression of MPM in a mouse model of MPM. Measurement of cytokines from the pleural lavage showed that mice implanted with MPM cells expressing EPCR had elevated levels of IFNγ and TNFα compared to mice implanted with MPM cells lacking EPCR. In vitro studies demonstrated that EPCR expression renders MPM cells highly susceptible to IFNγ + TNFα-induced apoptosis. Intrapleural injection of Ad.EPCR into mice with an established MPM originating from MPM cells lacking EPCR reduced the progression of tumor growth. Ad.EPCR treatment elicited recruitment of macrophages and NK cells into the tumor microenvironment and increased IFNγ and TNFα levels in the pleural space. Ad.EPCR treatment resulted in a marked increase in tumor cell apoptosis. In summary, our data show that EPCR expression in MPM cells promotes tumor cell apoptosis, and intrapleural EPCR gene therapy suppresses MPM progression.

Lung cancer: Biology and treatment options

Lung cancer remains the leading cause of cancer mortality in men and women in the U.S. and worldwide. About 90% of lung cancer cases are caused by smoking and the use of tobacco products. However, other factors such as radon gas, asbestos, air pollution exposures, and chronic infections can contribute to lung carcinogenesis. In addition, multiple inherited and acquired mechanisms of susceptibility to lung cancer have been proposed. Lung cancer is divided into two broad histologic classes, which grow and spread differently: small-cell lung carcinomas (SCLCs) and non-small cell lung carcinomas (NSCLCs). Treatment options for lung cancer include surgery, radiation therapy, chemotherapy, and targeted therapy. Therapeutic-modalities recommendations depend on several factors, including the type and stage of cancer. Despite the improvements in diagnosis and therapy made during the past 25 years, the prognosis for patients with lung cancer is still unsatisfactory. The responses to current standard therapies are poor except for the most localized cancers. However, a better understanding of the biology pertinent to these challenging malignancies, might lead to the development of more efficacious and perhaps more specific drugs. The purpose of this review is to summarize the recent developments in lung cancer biology and its therapeutic strategies, and discuss the latest treatment advances including therapies currently under clinical investigation.

Latest developments in our understanding of the pathogenesis of mesothelioma and the design of targeted therapies

Malignant mesothelioma is an aggressive cancer whose pathogenesis is causally linked to occupational exposure to asbestos. Familial clusters of mesotheliomas have been observed in settings of genetic predisposition. Mesothelioma incidence is anticipated to increase worldwide in the next two decades. Novel treatments are needed, as current treatment modalities may improve the quality of life, but have shown modest effects in improving overall survival. Increasing knowledge on the molecular characteristics of mesothelioma has led to the development of novel potential therapeutic strategies, including: molecular targeted approaches, that is the inhibition of vascular endothelial growth factor with bevacizumab; immunotherapy with chimeric monoclonal antibody, immunotoxin, antibody drug conjugate, vaccine and viruses; inhibition of asbestos-induced inflammation, that is aspirin inhibition of HMGB1 activity may decrease or delay mesothelioma onset and/or growth. We elaborate on the rationale behind new therapeutic strategies, and summarize available preclinical and clinical results, as well as efforts still ongoing.

Malignant Peritoneal Mesothelioma in an Adolescent Male With BAP1 Deletion

Diffuse malignant peritoneal mesotheliomas in children are uncommon, aggressive tumors with a grave prognosis. We herein report the clinical, radiologic, and pathologic findings of a 16-year-old male. The adolescent presented with a history of abdominal pain, nausea and daily, nonbilious, nonbloody emesis for 3 weeks. Radiographic imaging suggested small bowel obstruction. The diagnostic work-up and differential diagnoses are discussed. Histologically, the tumor was composed of epithelioid cells with a papillary and glandular architectural pattern. A few glands appeared to produce mucinous material. Histochemistry revealed PAS diastase resistant mucin, an inconspicuous finding in diffuse malignant peritoneal mesothelioma. An extensive immunohistochemistry panel (calretinin, WT-1, D2-40, CK 7, CAM 5.2, CK 5/6, CEA, B72.3, CK 20, CD10, CD30, CD15, CD117, PLAP, S100, TFE3, and EMA) confirmed the diagnosis. Of special interest, BAP1 staining was cytoplasmic and consistent with 3p deletion detected by conventional cytogenetics. The ultrastructural analysis demonstrated long microvilli, desmosomes, and intercellular junctions which further supported the diagnosis.

Inhibition of mesothelioma cancer stem-like cells with adenovirus-mediated NK4 gene therapy

Malignant mesothelioma (MM) is a highly invasive and chemoresistant malignancy induced by asbestos fibers. NK4, a hepatocyte growth factor antagonist and angiogenesis inhibitor, consists of the N-terminal hairpin domain and four kringle domains of the α-chain of hepatocyte growth factor. The therapeutic potential of NK4 has been demonstrated in a variety of tumor types. However, the mechanisms by which NK4 inhibits tumor growth have not been well delineated. In this study, it is shown that the NK4 adenovirus (Ad-NK4) potently inhibits cell viability, invasiveness and tumorigenicity of human MM cells. Significantly, this study demonstrates for the first time that Ad-NK4 inhibits cancer stem-like cell (CSC) properties as assessed by spheroid formation assay, side population analysis and flow cytometric sorting of CD24 cells. In addition to inhibiting phosphorylation of Met and AKT, Ad-NK4 markedly suppressed the active form of β-catenin, a key mediator of both Wnt and AKT pathways. It is further demonstrated that expression of NK4 suppresses β-catenin nuclear localization and transcriptional activity. Intriguingly, the expression levels of Oct4 and Myc, two critical stem cell factors and downstream targets of β-catenin, were also diminished by Ad-NK4. Furthermore, the strong antitumor effect of NK4 was found to be linked to its ability to inhibit CSCs as revealed by immunohistochemical examination of tumor specimens from a mouse xenograft model of human MM. These findings suggest that NK4 acts as a CSC inhibitor by impeding Met/AKT/β-catenin signaling and holds promise for achieving durable therapeutic responses in MM by constraining the CSC component of these aggressive tumors.

Significance of serum mesothelin in an asbestos-exposed population in the Czech Republic

AIMS

Pleural mesothelioma is a highly aggressive and difficult-to-treat form of cancer induced by asbestos in 80-90% of cases. The population group most at risk of the condition are asbestos-exposed workers. Mesothelin or soluble mesothelin-related protein (SMRP) is studied as a potential marker of mesothelioma in the at-risk population.

METHODS

The study comprised 239 subjects with a mean duration of occupational exposure to asbestos of 19.9 years. In all of them, a complete medical history was taken, focused on exposure duration and a physical examination, a chest X-ray or other imaging investigations and a lung function test were performed. Their serum SMRP levels were measured and biopsy samples were taken to diagnose pleural disease. Based on the above examinations, the subjects were classified into subgroups and serum SMRP concentrations were statistically analyzed with respect to individual parameters.

RESULTS

In asbestos-exposed individuals, mesothelin levels were significantly higher in those with pathological X-ray findings than in those with normal X-ray results (0.78 ± 0.63 vs. 0.50 ± 0.35, P<0.0001). The group of patients with benign disease had statistically significantly higher mesothelin levels than those with normal X-ray findings (0.755 ± 0.543 vs. 0.50 ± 0.35, P<0.001). In the group with present malignant processes, mesothelin levels were higher than in individuals with benign disease (1.19 ± 0.89 vs. 0.76 ± 0.54, P=0.015). Only a weak correlation was found between mesothelin levels and asbestos exposure duration. There were relatively high sensitivity and high specificity (75% and 90.6%, respectively) of serum mesothelin for pleural mesothelioma. However, given the small number of mesothelioma cases in the group, the results cannot be considered as statistically significant.

CONCLUSIONS

In persons followed up for asbestos exposure, increased mesothelin levels signalize pathological processes in the chest and correlate with severity of the disease. The study suggests that mesothelin cannot be considered a reliable marker for the early stage of malignant degeneration of pleural disease but only an additional criterion for examination of the followed-up individuals.

Cilengitide inhibits attachment and invasion of malignant pleural mesothelioma cells through antagonism of integrins αvβ3 and αvβ5

Malignant pleural mesothelioma (MPM) is an almost invariably fatal, asbestos-related malignancy arising from the mesothelial membrane lining the thoracic cavities. Despite some improvements in treatment, therapy is not considered curative and median survival following diagnosis is less than 1 year. Although still classed as a rare cancer, the incidence of MPM is increasing, and the limited progress in treating the disease makes the identification of new therapies a priority. As there is evidence for expression of the integrins αvβ3 and αvβ5 in MPM, there is a rationale for investigating the effects on MPM of cilengitide, a synthetic peptide inhibitor of integrin αv heterodimer with high specificity for αvβ3 and αvβ5. In mesothelial cells (MC) and 7 MPM cell lines, growth inhibition by cilengitide was associated with the expression level of its target integrins. Furthermore, cilengitide caused cell detachment and subsequent death of anoikis-sensitive cells. It also suppressed invasion of MPM cells in monolayer and three-dimensional cultures. Gene knockdown experiments indicated that these effects of cilengitide were, at least partly, due to antagonism of αvβ3 and αvβ5.

Malignant mesothelioma presenting as a gradually enlarging pneumothorax

Malignant mesothelioma is an extremely aggressive tumor arising from the pleura with median survival of approximately 9–12 months. It can rarely present as a spontaneous pneumothorax. Less than 35 cases of malignant mesothelioma presenting as spontaneous pneumothorax have been reported in the literature. Pathology may show florid mesothelial hyperplasia. We herein report a case of mesothelioma presenting as a pneumothorax that gradually enlarged over a one-year period and also review the relevant literature.

Changes of mesothelin and osteopontin levels over time in formerly asbestos-exposed power industry workers

PURPOSE

In patients developing malignant pleural mesothelioma (MPM) or lung cancer, using effective tumour markers is the quickest way to ensure early diagnosis and improve survival time. The aim of our study was to assess the influence of age and asbestos exposure on the blood levels of the proposed tumour markers, mesothelin and osteopontin, and to determine the change of these markers over time.

METHODS

We analysed 3,329 blood samples of 2,262 participants including 1,894 formerly asbestos-exposed power industry workers, a mixed group of 266 participants with an unknown history of asbestos exposure and a group of 102 non-asbestos-exposed controls. Marker concentrations were determined using commercial ELISA kits.

RESULTS

While age had a strong influence on marker levels, there was no association between exposure duration or benign asbestos-related disease and marker levels. In order to assess the maximum increase that can be expected to occur in asbestos-exposed workers those with an at least 10 % increase were selected (n = 290 for mesothelin and n = 81 for osteopontin). The 95th percentile of the annual change was 0.402 nmol/l for mesothelin and 334 ng/ml for osteopontin. In two patients with MPM and five with lung cancer, we could obtain more than one marker result before the diagnosis was made. Both MPM patients showed a steep increase of mesothelin levels.

CONCLUSIONS

Fixed cut-off values for deciding between intensive clinical work-up and continued surveillance appeared inadequate for the evaluated markers. While general conclusions cannot be drawn, we can say that the results of the two patients would be consistent with a mesothelin increase between 6 and 18 months before clinical symptoms developed.

Glutathione S-transferase P1-1 as a target for mesothelioma treatment

Malignant pleural mesothelioma is a poorly responsive tumor known to overexpress the phase II detoxification enzyme glutathione-S-transferase, which catalyzes the conjugation between glutathione and platinum(II)-containing drugs. Therefore, we evaluated the effect of the strong glutathione S-transferase inhibitor NBDHEX on human mesothelioma cell lines (MSTO-211H, MPP89, MM-B1 and Mero 48a) featuring the most common mesothelioma phenotypes: epithelioid and biphasic. Even though a different response to NBDHEX was observed, the molecule was very effective on all cell lines tested, triggering a sustained activation of both JNK and p38, followed by caspase activation and apoptosis. NBDHEX also caused severe oxidative stress in the MPP89 cells and, to a lesser extent, in the MMB1 cells, while it did not cause a significant redox imbalance in the other cell lines. The efficacy of the drug was found to be comparable or even higher than that of cisplatin. Moreover, it showed synergistic or additive effects when used in combination with cisplatin. In conclusion, NBDHEX was effective on mesothelioma cell lines, with IC(50) values in the low micromolar range (IC(50) between 1 and 4 μM). These findings indicate that NBDHEX, alone or in combination with cisplatin, is a promising new strategy for treating this rare and aggressive malignancy.

Arsenic, asbestos and radon: emerging players in lung tumorigenesis

The cause of lung cancer is generally attributed to tobacco smoking. However lung cancer in never smokers accounts for 10 to 25% of all lung cancer cases. Arsenic, asbestos and radon are three prominent non-tobacco carcinogens strongly associated with lung cancer. Exposure to these agents can lead to genetic and epigenetic alterations in tumor genomes, impacting genes and pathways involved in lung cancer development. Moreover, these agents not only exhibit unique mechanisms in causing genomic alterations, but also exert deleterious effects through common mechanisms, such as oxidative stress, commonly associated with carcinogenesis. This article provides a comprehensive review of arsenic, asbestos, and radon induced molecular mechanisms responsible for the generation of genetic and epigenetic alterations in lung cancer. A better understanding of the mode of action of these carcinogens will facilitate the prevention and management of lung cancer related to such environmental hazards.

Transforming growth factor-β-induced protein (TGFBI) suppresses mesothelioma progression through the Akt/mTOR pathway

As an uncommon cancer, mesothelioma is very hard to treat with a low average survival rate owing to its usual late detection and being highly invasive. The link between asbestos exposure and the development of mesothelioma in humans is unequivocal. TGFBI, a secreted protein that is induced by transforming growth factor-β in various human cell types, has been shown to be associated with tumorigenesis in various types of tumors. It has been demonstrated that TGFBI expression is markedly suppressed in asbestos-induced tumorigenic cells, while an ectopic expression of TGFBI significantly suppresses tumorigenicity and progression in human bronchial epithelial cells. In order to delineate a potential role of TGFBI in mediating the molecular events that occur in mesothelioma tumorigenesis, we generated stable TGFBI knockdown mutants from the mesothelium cell line Met-5A by using an shRNA approach, and secondly created ectopic TGFBI overexpression mutants from the mesothelioma cell line H28 in which TGFBI is absent. We observed that in the absence of TGFBI, the knockdown mesothelial and mesothelioma cell lines exhibited an elevated proliferation rate, enhanced plating efficiency, increased anchorage-independent growth, as well as an increased cellular protein synthesis rate as compared with their respective controls. Furthermore, cell cycle regulatory proteins c-myc/cyclin D1/phosphor-Rb were upregulated; a more active PI3K/Akt/mTOR signaling pathway was also detected in TGFBI-depleted cell lines. These findings suggest that TGFBI may repress mesothelioma tumorigenesis and progression via the PI3K/Akt signaling pathway.

Genetically engineered oncolytic Newcastle disease virus effectively induces sustained remission of malignant pleural mesothelioma

Malignant pleural mesothelioma is a highly aggressive tumor. Alternative treatment strategies such as oncolytic viral therapy may offer promising treatment options in the future. In this study, the oncolytic efficacy and induction of tumor remission by a genetically engineered Newcastle disease virus [NDV; NDV(F3aa)-GFP; GFP, green fluorescent protein] in malignant pleural mesothelioma is tested and monitored by bioluminescent tumor imaging. The efficacy of NDV(F3aa)-GFP was tested against several mesothelioma cell lines in vitro. Firefly luciferase-transduced MSTO-211H* orthotopic pleural mesothelioma tumor-bearing animals were treated with either single or multiple doses of NDV(F3aa)-GFP at different time points (days 1 and 10) after tumor implantation. Tumor burden was assessed by bioluminescence imaging. Mesothelioma cell lines exhibited dose-dependent susceptibility to NDV lysis in the following order of sensitivity: MSTO-211H > MSTO-211H* > H-2452 > VAMT > JMN. In vivo studies with MSTO-211H* cells showed complete response to viral therapy in 65% of the animals within 14 days after treatment initiation. Long-term survival in all of these animals was >50 days after tumor installation (control animals, <23 d). Multiple treatment compared with single treatment showed a significantly better response (P = 0.005). NDV seems to be an efficient viral oncolytic agent in the therapy of malignant pleural mesothelioma in an orthotopic pleural mesothelioma tumor model.

A diagnostic assay based on microRNA expression accurately identifies malignant pleural mesothelioma

The definitive identification of malignant pleural mesothelioma (MPM) has significant clinical implications, yet other malignancies often involve the lung pleura, confounding the diagnosis of MPM. In the absence of accurate markers, MPM can be difficult to distinguish from peripheral lung adenocarcinoma and metastatic epithelial cancers. MicroRNA expression is tissue-specific and highly informative for identifying tumor origin. We identified microRNA biomarkers for the differential diagnosis of MPM and developed a standardized microRNA-based assay. Formalin-fixed, paraffin-embedded samples of 33 MPM and 210 carcinomas were used for assay development. Using microarrays, we identified microRNAs differentially expressed between MPM and various carcinomas. Hsa-miR-193-3p was overexpressed in MPM, while hsa-miR-200c and hsa-miR-192 were overexpressed in peripheral lung adenocarcinoma and carcinomas that frequently metastasize to lung pleura. We developed a standardized diagnostic assay based on the expression of these microRNAs. The assay reached a sensitivity of 100% and a specificity of 94% in a blinded validation set of 68 samples from the lung and pleura. This diagnostic assay can provide a useful tool in the differential diagnosis of MPM from other malignancies in the pleura.

Absence of Simian virus 40, BK, and JC polyomavirus DNA in squamous cell carcinoma limited to the oral cavity

BACKGROUND

Head and neck squamous cell carcinomas (SCCs) are among the most aggressive types of cancer. The Simian virus 40 (SV40), which is a polyomavirus known for its oncogenic potential, was found as a contaminant of oral vaccines and has been related to human pleomorphic adenoma in the parotid gland. The aim of this study was to evaluate the presence of SV40 and 2 human polyomaviruses-BK virus (BKV) and JC virus (JCV)-in a large sample of SCCs of the oral cavity.

METHODS

Quantitative real-time polymerase chain reaction (PCR) was used to evaluate virus load.

RESULTS

Overall, the prevalence of SV40, BKV, and JCV in oral SCC was negligible. Matched-pair case-control analysis indicated that prevalence among the controls did not significantly differ with respect to analyzed cases.

CONCLUSION

The results did not indicate a major role for SV40, BKV, and JCV in the etiology of oral SCC.

The urokinase receptor supports tumorigenesis of human malignant pleural mesothelioma cells

Malignant pleural mesothelioma (MPM) is a lethal neoplasm for which current therapy is unsatisfactory. The urokinase plasminogen activator receptor (uPAR) is associated with increased virulence of many solid neoplasms, but its role in the pathogenesis of MPM is currently unclear. We found that REN human pleural MPM cells expressed 4- to 10-fold more uPAR than MS-1 or M9K MPM cells or MeT5A human pleural mesothelial cells. In a new orthotopic murine model of MPM, we found that the kinetics of REN cell tumorigenesis is accelerated versus MS-1 or M9K cells, and that REN instillates generated larger tumors expressing increased uPAR, were more invasive, and caused earlier mortality. While REN, MS-1, and M9K tumors were all associated with prominent extravascular fibrin deposition, excised REN tumor homogenates were characterized by markedly increased uPAR at both the mRNA and protein levels. REN cells exhibited increased thymidine incorporation, which was attenuated in uPAR-silenced cells (P < 0.01). REN cells traversed three-dimensional fibrin gels while MS-1, M9K, and MeT5A cells did not. uPAR siRNA or uPAR blocking antibodies decreased REN cell migration and invasion, while uPA and fetal bovine serum augmented the effects. Transfection of relatively low uPAR expressing MS-1 cells with uPAR cDNA increased proliferation and migration in vitro and tumor formation in vivo. These observations link overexpression of uPAR to the pathogenesis of MPM, demonstrate that this receptor contributes to accelerated tumor growth in part through interactions with uPA, and suggest that uPAR may be a promising target for therapeutic intervention.

Soluble mesothelin related peptides (SMRP) and osteopontin as protein biomarkers for malignant mesothelioma: analytical validation of ELISA based assays and characterization at mRNA and protein levels

BACKGROUND

There is a need to identify reliable markers for malignant mesothelioma. Soluble mesothelin related peptides (SMRP) and osteopontin (OPN) have gained interest in recent years for this purpose.

METHODS

SMRP (Fujirebio Diagnostics Inc.) and OPN (R&D Inc.) ELISA methods were evaluated for multiple parameters. Concentrations were measured in blood from patients with mesothelioma, normal healthy volunteers, and patients with other (non-mesothelioma) cancers. In silico analysis was performed using the GeoProfiles database. At the protein level, SMRP and OPN were measured in cell culture supernatants, and values were compared in patients pre- and post-extrapleural pneumonectomy.

RESULTS

The SMRP assay demonstrates intra-assay CVs of 2.3% and 3% (at 4.6 nM and 13.7 nM, respectively), and inter-assay CVs of 3.5% and 3.7% at the same concentrations. The limit of detection (LOD) is 0.182 nM. The OPN assay demonstrates intra-assay CVs of 5.8%, 4.1%, and 5.2% (at 1.9, 5.1, and 11.1 ng/mL, respectively), and inter-assay CVs of 8.5%, 8.4%, and 12.1% at the same concentrations. The LOD is 0.032 ng/mL. Both SMRP and OPN in mesothelioma patients were significantly higher than in patients with other (non-mesothelioma) cancer and in healthy volunteers. The two markers do not appear to correlate with each other and exhibit different tissue expression patterns. Protein concentrations of these markers are highest in different sets of cell lines. Finally, SMRP but not OPN concentrations were decreased in five of seven consecutive patients after extrapleural pneumonectomy, compared to their respective pre-operative values.

CONCLUSIONS

These assays provide reliable and reproducible quantitation of SMRP and OPN proteins. Both are increased in mesothelioma patients compared to non-mesothelioma controls. However, the two analytes do not correlate with each other and show distinct expression profiles and protein expression. Concentrations of SMRP but not OPN are decreased in post-surgical samples. Our results further characterize these markers, establish assay performance characteristics, and lay the groundwork for further studies to measure these markers in blood.

Diagnostic performance of soluble mesothelin and megakaryocyte potentiating factor in mesothelioma

RATIONALE

Soluble mesothelin (SM) is currently the reference serum biomarker of malignant pleural mesothelioma (MPM). Megakaryocyte potentiating factor (MPF), which originates from the same precursor protein, is potentially more sensitive, yet lacks validation.

OBJECTIVES

To analyze the diagnostic performance of MPF as an MPM biomarker and compare this performance with SM.

METHODS

A total of 507 participants were enrolled in six cohorts: healthy control subjects (n = 101), healthy asbestos-exposed individuals (n = 89), and patients with benign asbestos-related disease (n = 123), benign respiratory disease (n = 46), lung cancer (n = 63), and MPM (n = 85). Sera were analyzed for SM and MPF levels using the Mesomark and Human MPF ELISA kit, respectively.

MEASUREMENTS AND MAIN RESULTS

SM and MPF levels differed significantly between patients with MPM and participants from each other cohort (P < 0.001). Receiver operating characteristics curve analysis did not reveal a significant difference between both markers in area under curve (AUC) for distinguishing MPM from all cohorts jointly (SM = 0.871, MPF = 0.849; P = 0.28). At 95% specificity, SM and MPF had a sensitivity of 64% (cutoff = 2.00 nmol/L) and 68% (cutoff = 12.38 ng/ml), respectively. Combining both markers did not improve the diagnostic performance.

CONCLUSIONS

In this prospective multicenter study, MPF is validated as a highly performant MPM biomarker. The similar AUC values of SM and MPF, together with the limited difference in sensitivity, show that both serum biomarkers have an equivalent diagnostic performance.

Mechanisms of FUS1/TUSC2 deficiency in mesothelioma and its tumorigenic transcriptional effects

Background

FUS1/TUSC2 is a novel tumor suppressor located in the critical 3p21.3 chromosomal region frequently deleted in multiple cancers. We previously showed that Tusc2-deficient mice display a complex immuno-inflammatory phenotype with a predisposition to cancer. The goal of this study was to analyze possible involvement of TUSC2 in malignant pleural mesothelioma (MPM) - an aggressive inflammatory cancer associated with exposure to asbestos.

Methods

TUSC2 insufficiency in clinical specimens of MPM was assessed via RT-PCR (mRNA level), Representational Oligonucleotide Microarray Analysis (DNA level), and immunohistochemical evaluation (protein level). A possible link between TUSC2 expression and exposure to asbestos was studied using asbestos-treated mesothelial cells and ROS (reactive oxygen species) scavengers. Transcripional effects of TUSC2 in MPM were assessed through expression array analysis of TUSC2-transfected MPM cells.

Results

Expression of TUSC2 was downregulated in ~84% of MM specimens while loss of TUSC2-containing 3p21.3 region observed in ~36% of MPMs including stage 1 tumors. Exposure to asbestos led to a transcriptional suppression of TUSC2, which we found to be ROS-dependent. Expression array studies showed that TUSC2 activates transcription of multiple genes with tumor suppressor properties and down-regulates pro-tumorigenic genes, thus supporting its role as a tumor suppressor. In agreement with our knockout model, TUSC2 up-regulated IL-15 and also modulated more than 40 other genes (~20% of total TUSC2-affected genes) associated with immune system. Among these genes, we identified CD24 and CD274, key immunoreceptors that regulate immunogenic T and B cells and play important roles in systemic autoimmune diseases. Finally, clinical significance of TUSC2 transcriptional effects was validated on the expression array data produced previously on clinical specimens of MPM. In this analysis, 42 TUSC2 targets proved to be concordantly modulated in MM serving as disease discriminators.

Conclusion

Our data support immuno-therapeutic potential of TUSC2, define its targets, and underscore its importance as a transcriptional stimulator of anti-tumorigenic pathways.

Design and modification of EGF4KDEL 7Mut, a novel bispecific ligand-directed toxin, with decreased immunogenicity and potent anti-mesothelioma activity

BACKGROUND

Potency, immunogenicity, and toxicity are three problems that limit the use of targeted toxins in solid tumour therapy.

METHODS

To address potency, we used genetic engineering to develop a novel bispecific ligand-directed toxin (BLT) called EGF4KDEL, a novel recombinant anti-mesothelioma agent created by linking human epidermal growth factor (EGF) and interleukin-4 (IL-4) to truncated pseudomonas exotoxin (PE38) on the same single-chain molecule. Immunogenicity was reduced by mutating seven immunodominant B-cell epitopes on the PE38 molecule to create a new agent, EGF4KDEL 7Mut.

RESULTS

In vitro, bispecific EGF4KDEL showed superior anti-mesothelioma activity compared with its monospecific counterparts. Toxicity in mice was diminished by having both ligands on the same molecule, allowing administration of a 10-fold greater dose of BLT than a mixture of monomeric IL4KDEL and EGFKDEL. EGF4KDEL 7Mut, retained all of its functional activity and induced about 87% fewer anti-toxin antibodies than mice given the parental, non-mutated form. In vivo, intraperitoneal (IP) injection of the BLT showed significant (P<0.01) and impressive effects against two aggressive, malignant IP mesothelioma models when treatment was begun 14-16 days post tumour innoculation.

CONCLUSION

These data show that EGF4KDEL 7Mut is a promising new anti-mesothelioma agent that was developed to specifically address the obstacles facing clinical utility of targeted toxins.

Theoretical model of treatment strategies for clear cell carcinoma of the ovary: focus on perspectives

OBJECTIVES

Among epithelial ovarian cancer (EOC), clear cell carcinomas (CCC) differ from the other histologic types with respect to their clinical characteristics, carcinogenesis and prognosis. The aim of this review is to summarize the current knowledge and future perspective on the new therapeutic targets and treatment strategies for CCC.

MATERIALS AND METHODS

The present article reviews the English language literature for preclinical and clinical trials and promising molecular targets on CCC of the ovary, based on the gene expression profiling studies.

RESULTS

Here, we show that (1) the expression of the genes involved in transcription, signaling, cell cycle, adhesion, matrix, proteinase, and detoxification was greatly increased in the CCC carcinogenesis; (2) upregulation of hepatocyte nuclear factor-1beta (HNF-1beta) and Polo-like kinase (PLK)-Early mitotic inhibitor-1 (Emi1) as well as their downstream targets are specifically found in most CCC. The promising molecular targeting approach will emerge in the context of HNF-1beta and PLK-Emi1 biology; and 3) several significant common pathways observed in CCC of the ovary overlap the datasets identified in CCC of the kidney. To improve the outcome in CCC therapy, we must learn various adaptive treatment strategies for renal CCC, although it is not supported by any preliminary clinical data.

CONCLUSION

The inhibitors that target HNF-1beta and PLK-Emi1 and their downstream signaling molecules would be evaluated. In addition, the therapy currently used in renal CCC should be considered as an alternative for the present treatments or an attractive therapeutic option for ovarian CCC. The challenges accompanying the recent advance are described in this review article.

Malignant mesothelioma

Malignant mesothelioma is a fatal asbestos-associated malignancy originating from the lining cells (mesothelium) of the pleural and peritoneal cavities, as well as the pericardium and the tunica vaginalis. The exact prevalence is unknown but it is estimated that mesotheliomas represent less than 1% of all cancers. Its incidence is increasing, with an expected peak in the next 10–20 years. Pleural malignant mesothelioma is the most common form of mesothelioma. Typical presenting features are those of chest pain and dyspnoea. Breathlessness due to a pleural effusion without chest pain is reported in about 30% of patients. A chest wall mass, weight loss, sweating, abdominal pain and ascites (due to peritoneal involvement) are less common presentations. Mesothelioma is directly attributable to occupational asbestos exposure with a history of exposure in over 90% of cases. There is also evidence that mesothelioma may result from both para-occupational exposure and non-occupational "environmental" exposure. Idiopathic or spontaneous mesothelioma can also occur in the absence of any exposure to asbestos, with a spontaneous rate in humans of around one per million. A combination of accurate exposure history, along with examination radiology and pathology are essential to make the diagnosis. Distinguishing malignant from benign pleural disease can be challenging. The most helpful CT findings suggesting malignant pleural disease are 1) a circumferential pleural rind, 2) nodular pleural thickening, 3) pleural thickening of > 1 cm and 4) mediastinal pleural involvement. Involvement of a multidisciplinary team is recommended to ensure prompt and appropriate management, using a framework of radiotherapy, chemotherapy, surgery and symptom palliation with end of life care. Compensation issues must also be considered. Life expectancy in malignant mesothelioma is poor, with a median survival of about one year following diagnosis.

Peritoneal mesothelioma

OPINION STATEMENT

Malignant peritoneal mesothelioma (MPM) is an aggressive neoplasm that rapidly spreads within the confines of the abdominal cavity to involve most accessible peritoneal and omental surfaces. Current treatment options are unsatisfactory, and new approaches are needed. Recent publications have reported improved survival with an intensive loco-regional treatment strategy including cytoreductive surgery (CRS) along with hyperthermic intraperitoneal chemotherapy (HIPEC). We have noted at our institution prolonged survival in selected patients after intensive multimodality treatment. Our most recently reported trial included initial laparatomy with omentectomy, resection of peritoneal implants, and placement of bilateral peritoneal Portacath; repeated courses of intraperitoneal chemotherapy with doxorubicin, cisplatin, and interferon gamma; second-look laparotomy; and intraoperative hyperthermic perfusion with mitomycin and cisplatin, followed by whole abdominal radiation. To date there have been no universally accepted treatments for MPM. Unless referred to a specialty center, patients are routinely treated with pemetrexed and cisplatin which has been shown to increase survival in pleural mesothelioma.