Estrogen receptor-beta affects the prognosis of human malignant mesothelioma

CD9 expression as a favorable prognostic marker for patients with malignant mesothelioma

CD9 is involved in cell growth, adhesion and motility and its expression is reported to be of prognostic significance in various types of human malignancies. We found increased cell migration in the mesothelioma cell lines MSTO-211H and TUM1 following in vitro shRNA-mediated knockdown of CD9 expression. We investigated CD9 expression in 112 malignant pleural mesotheliomas. CD9 expression was observed in 62 of 71 epithelioid, 13 of 20 biphasic and only 1 of 21 sarcomatoid mesotheliomas. Among the epithelioid mesotheliomas (EMs), CD9 expression was observed in all of the 33 cases with a differentiated type (EM-D) and in 29 of the 38 cases with a less-differentiated type (EM-LD). Patients with CD9 expression showed higher 1- and 2-year survival rates (63 and 25%) compared to the patients without CD9 expression (39 and 11%). Univariate analysis revealed that patients with CD9 expression demonstrated a more favorable survival (P=0.0025) along with other clinicopathological factors, including age younger than 60 years, IMIG stage I–II, epithelioid histology, EM-D and patients who underwent extrapleural pneumonectomy or received chemotherapy. Multivariate analysis identified CD9 expression as an independent prognostic factor with a hazard ratio (HR) of 1.99 in the analysis of all mesotheliomas (P=0.0261) and an HR of 2.60 in the analysis of EMs (P=0.0376). CD9 expression is an independent favorable prognostic marker of malignant mesothelioma.

Perifosine as a potential novel anti-cancer agent inhibits EGFR/MET-AKT axis in malignant pleural mesothelioma

BACKGROUND

PI3K/AKT signalling pathway is aberrantly active and plays a critical role for cell cycle progression of human malignant pleural mesothelioma (MMe) cells. AKT is one of the important cellular targets of perifosine, a novel bio-available alkylphospholipid that has displayed significant anti-proliferative activity in vitro and in vivo in several human tumour model systems and is currently being tested in clinical trials.

METHODS

We tested Perifosine activity on human mesothelial cells and different mesothelioma cell lines, in order to provide evidence of its efficacy as single agent and combined therapy.

RESULTS

We demonstrate here that perifosine, currently being evaluated as an anti-cancer agent in phase 1 and 2 clinical trials, caused a dose-dependent reduction of AKT activation, at concentrations causing MMe cell growth arrest. In this study we firstly describe that MMe cells express aside from AKT1 also AKT3 and that either the myristoylated, constitutively active, forms of the two proteins, abrogated perifosine-mediated cell growth inhibition. Moreover, we describe here a novel mechanism of perifosine that interferes, upstream of AKT, affecting EGFR and MET phosphorylation. Finally, we demonstrate a significant increase in cell toxicity when MMe cells were treated with perifosine in combination with cisplatin.

CONCLUSIONS

This study provides a novel mechanism of action of perifosine, directly inhibiting EGFR/MET-AKT1/3 axis, providing a rationale for a novel translational approach to the treatment of MMe.

Sustained expression of steroid receptor coactivator SRC-2/TIF-2 is associated with better prognosis in malignant pleural mesothelioma

INTRODUCTION

Estrogen receptor beta (ERβ) overexpression by malignant pleural mesothelioma (MPM) tumor cells correlates with enhanced patient survival. ER-regulated transcription is mediated by the p160 family of steroid receptor coactivators (SRCs), and SRC isoform overexpression is associated with worse prognosis in many steroid-related malignancies. The aim of this study was to establish whether SRC isoform expression varied between individual MPM tumors with positive or negative prognostic significance.

METHODS

Immunohistochemical analysis of tumor biopsies from 89 subjects with confirmed histological diagnosis of MPM and biopsies from 3 normal control subjects was performed to detect the expression of SRC-1, SRC-2 (TIF-2), SRC-3 (AIB-1), and ERβ. Allred scores for expression of ERβ and each of the SRCs were determined, and Kaplan-Meier survival curves were calculated to correlate biomarker expression, gender, and histology type with postdiagnosis survival.

RESULTS

ERβ and all the SRCs were expressed at high levels in normal pleural mesothelium, and expression of each biomarker was reduced or lost in a subset of the MPM subjects; however, postdiagnosis survival only significantly correlated with TIF-2 expression. Low or intermediate expression of TIF-2 correlated with reduced median postdiagnosis survival (9 months) compared with those subjects whose tumors highly expressed TIF-2 (20 months) (p = 0.036, log-rank test).

CONCLUSIONS

Maintained high expression of TIF-2 in tumor cells is a positive prognostic indicator for postdiagnosis survival in patients with confirmed MPM. This is the first clinical study to correlate high TIF-2 expression with improved patient prognosis in any malignancy.

The ticking time-bomb of asbestos: its insidious role in the development of malignant mesothelioma

The relationship between asbestos exposure and malignant mesothelioma (MM) has been well established. Despite bans on asbestos use in an increasing number of nations, the prolonged latency from exposure to diagnosis, and the ongoing presence and use of these dangerous fibres, have led to the increasing prevalence of this deadly disease worldwide. Whilst occupational contact has been implicated in the bulk of diagnosed cases over the past 50 years, a significant proportion of disease has been linked to para-occupational, domestic and environmental exposure. In this review, we will provide an update on the impact of historical and ongoing asbestos contact in both occupational and non-occupational settings. Furthermore, we will address the unresolved controversies surrounding the use of chrysotile asbestos, the effect of gender and genetics on development of this disease, childhood mesothelioma and co-aetiological factors including SV40 exposure.

Malignant mesothelioma: facts, myths, and hypotheses

Malignant mesothelioma (MM) is a neoplasm arising from mesothelial cells lining the pleural, peritoneal, and pericardial cavities. Over 20 million people in the US are at risk of developing MM due to asbestos exposure. MM mortality rates are estimated to increase by 5-10% per year in most industrialized countries until about 2020. The incidence of MM in men has continued to rise during the past 50 years, while the incidence in women appears largely unchanged. It is estimated that about 50-80% of pleural MM in men and 20-30% in women developed in individuals whose history indicates asbestos exposure(s) above that expected from most background settings. While rare for women, about 30% of peritoneal mesothelioma in men has been associated with exposure to asbestos. Erionite is a potent carcinogenic mineral fiber capable of causing both pleural and peritoneal MM. Since erionite is considerably less widespread than asbestos, the number of MM cases associated with erionite exposure is smaller. Asbestos induces DNA alterations mostly by inducing mesothelial cells and reactive macrophages to secrete mutagenic oxygen and nitrogen species. In addition, asbestos carcinogenesis is linked to the chronic inflammatory process caused by the deposition of a sufficient number of asbestos fibers and the consequent release of pro-inflammatory molecules, especially HMGB-1, the master switch that starts the inflammatory process, and TNF-alpha by macrophages and mesothelial cells. Genetic predisposition, radiation exposure and viral infection are co-factors that can alone or together with asbestos and erionite cause MM. J. Cell. Physiol. 227: 44-58, 2012. © 2011 Wiley Periodicals, Inc.

Data-driven information retrieval in heterogeneous collections of transcriptomics data links SIM2s to malignant pleural mesothelioma

Motivation: Genome-wide measurement of transcript levels is an ubiquitous tool in biomedical research. As experimental data continues to be deposited in public databases, it is becoming important to develop search engines that enable the retrieval of relevant studies given a query study. While retrieval systems based on meta-data already exist, data-driven approaches that retrieve studies based on similarities in the expression data itself have a greater potential of uncovering novel biological insights.

Results: We propose an information retrieval method based on differential expression. Our method deals with arbitrary experimental designs and performs competitively with alternative approaches, while making the search results interpretable in terms of differential expression patterns. We show that our model yields meaningful connections between biological conditions from different studies. Finally, we validate a previously unknown connection between malignant pleural mesothelioma and SIM2s suggested by our method, via real-time polymerase chain reaction in an independent set of mesothelioma samples.

Availability:Supplementary data and source code are available from http://www.ebi.ac.uk/fg/research/rex.

Contact:samuel.kaski@aalto.fi

Supplementary Information:Supplementary data are available at Bioinformatics online.

Importance of gender in diffuse malignant peritoneal mesothelioma

BACKGROUND

Combined therapy involving cytoreductive surgery (CRS) and perioperative intraperitoneal chemotherapy has been shown to improve survival outcomes for patients with diffuse malignant peritoneal mesothelioma (DMPM). The present study aims to investigate gender as a potential prognostic factor on overall survival.

PATIENTS AND METHODS

Over a period of two decades, 294 patients who underwent CRS and perioperative intraperitoneal chemotherapy were selected from a large multi-institutional registry to assess the prognostic significance of gender on overall survival.

RESULTS

Female patients were shown to have a significantly improved survival outcome than male patients (P < 0.001). Staging according to a recently proposed tumor-node-metastasis categorization system was significant in both genders. Older female patients had significantly worse survival than younger female patients (P = 0.019), a finding that was absent in male patients. Female patients with low-stage disease were found to have a very favorable long-term outcome after combined treatment.

CONCLUSIONS

Gender has demonstrated a significant impact on overall survival for patients with DMPM after CRS and perioperative intraperitoneal chemotherapy. An improved understanding of the role of estrogen in the pathogenesis of DMPM may improve the prognostication of patients and determine the role of adjuvant hormonal treatment in the future.

Estrogen receptor β

CONTEXT

A new class of estrogen receptors was discovered in 1996 and named estrogen receptor β (ER-B); the traditional estrogen receptor, which until a little more than 10 years ago was thought of as the only estrogen receptor in existence, is now called estrogen receptor α. Estrogen receptor β has at least 5 isoforms, which may have different functions and have different tissue distribution. The significance of ER-B expression in tumors was first demonstrated in breast cancer, with several studies demonstrating that women with ER-B-positive breast cancers treated with adjuvant tamoxifen have better survival, independent of estrogen receptor α expression. Pathologists need to be more aware of this increasingly important protein, as it will soon find its way into routine clinical practice.

OBJECTIVE

To provide pathologists with a concise review of ER-B, with special emphasis on current and potential clinical relevance.

DATA SOURCES

A search of the English literature in PubMed (National Library of Medicine, Bethesda, Maryland) for articles with titles including "estrogen receptor beta," with emphasis on "immunohistochemistry." Abstracts were reviewed, and selected articles were used as the basis for writing this review, mostly based on their relevance to pathology.

CONCLUSIONS

Estrogen receptor β and its isoforms have wider tissue distribution, including the gastrointestinal tract, lung, and brain, than the traditional estrogen receptor, now called estrogen receptor α. Estrogen receptor β expression in breast cancer is associated with favorable outcome in women treated with adjuvant tamoxifen, even in tumors negative for estrogen receptor α. The clinical significance of ER-B expression in tumors other than breast is currently under investigation.

Peritoneal mesothelioma in a woman who has survived for seven years: a case report

Introduction

Malignant peritoneal mesothelioma is a rare cancer with poor patient survival. Female gender has been identified as a positive prognostic factor. Recently, it has been suggested that the expression of estrogen receptor β in malignant mesothelioma leads to tumor suppression and a better prognosis.

Case presentation

We report the case of a 48-year-old Caucasian woman who is alive and disease-free seven years after the initial diagnosis and treatment of malignant peritoneal mesothelioma.

Conclusion

This patient's long survival may be attributable to a combination of factors, including minimal disease, complete cytoreductive surgery and hyperthermic intraperitoneal chemotherapy plus the estrogen receptor β positivity of the tumor.

Blocking of ERK1 and ERK2 sensitizes human mesothelioma cells to doxorubicin

BACKGROUND

Malignant mesotheliomas (MM) have a poor prognosis, largely because of their chemoresistance to anti-cancer drugs such as doxorubicin (Dox). Here we show using human MM lines that Dox activates extracellular signal-regulated kinases (ERK1 and 2), causally linked to increased expression of ABC transporter genes, decreased accumulation of Dox, and enhanced MM growth. Using the MEK1/2 inhibitor, U0126 and stably transfected shERK1 and shERK2 MM cell lines, we show that inhibition of both ERK1 and 2 sensitizes MM cells to Dox.

RESULTS

U0126 significantly modulated endogenous expression of several important drug resistance (BCL2, ABCB1, ABCC3), prosurvival (BCL2), DNA repair (BRCA1, BRCA2), hormone receptor (AR, ESR2, PPARγ) and drug metabolism (CYP3A4) genes newly identified in MM cells. In comparison to shControl lines, MM cell lines stably transfected with shERK1 or shERK2 exhibited significant increases in intracellular accumulation of Dox and decreases in cell viability. Affymetrix microarray analysis on stable shERK1 and shERK2 MM lines showed more than 2-fold inhibition (p ≤ 0.05) of expression of ATP binding cassette genes (ABCG1, ABCA5, ABCA2, MDR/TAP, ABCA1, ABCA8, ABCC2) in comparison to shControl lines. Moreover, injection of human MM lines into SCID mice showed that stable shERK1 or shERK2 lines had significantly slower tumor growth rates in comparison to shControl lines after Dox treatment.

CONCLUSIONS

These studies suggest that blocking ERK1 and 2, which play critical roles in multi-drug resistance and survival, may be beneficial in combination with chemotherapeutic drugs in the treatment of MMs and other tumors.

Estrogen receptor β exerts tumor repressive functions in human malignant pleural mesothelioma via EGFR inactivation and affects response to gefitinib

BACKGROUND

The role of estrogen and estrogen receptors in oncogenesis has been investigated in various malignancies. Recently our group identified estrogen receptor beta (ERβ) expression as an independent prognostic factor in the progression of human Malignant Pleural Mesothelioma (MMe), but the underlying mechanism by which ERβ expression in tumors determines clinical outcome remains largely unknown. This study is aimed at investigating the molecular mechanisms of ERβ action in MMe cells and disclosing the potential translational implications of these results.

METHODS

We modulated ERβ expression in REN and MSTO-211H MMe cell lines and evaluated cell proliferation and EGF receptor (EGFR) activation.

RESULTS

Our data indicate that ERβ knockdown in ER positive cells confers a more invasive phenotype, increases anchorage independent proliferation and elevates the constitutive activation of EGFR-coupled signal transduction pathways. Conversely, re-expression of ERβ in ER negative cells confers a more epithelioid phenotype, decreases their capacity for anchorage independent growth and down-modulates proliferative signal transduction pathways. We identify a physical interaction between ERβ, EGFR and caveolin 1 that results in an altered internalization and in a selective reduced activation of EGFR-coupled signaling, when ERβ is over-expressed. We also demonstrate that differential expression of ERβ influences MMe tumor cell responsiveness to the therapeutic agent: Gefitinib.

CONCLUSIONS

This study describes a role for ERβ in the modulation of cell proliferation and EGFR activation and provides a rationale to facilitate the targeting of a subgroup of MMe patients who would benefit most from therapy with Gefitinib alone or in combination with Akt inhibitors.

Characteristics of malignant pleural mesothelioma in women

BACKGROUND

The incidence of malignant pleural mesothelioma (MPM) is higher in men than in women, likely due to increased occupational asbestos exposure among men. Women also appear to experience better long-term survival. This study evaluates the role of gender in relation to established prognostic factors in MPM.

METHODS

We reviewed 715 cases of MPM treated with extrapleural pneumonectomy at our institution between July 1987 and December 2008. Data for patients with epithelial and nonepithelial tumors were analyzed separately. Kaplan-Meier and Cox regression analyses were used to estimate survival for various cohorts to assess the relationship between gender and survival independent of age at surgery, stage, side, and preoperative laboratory studies.

RESULTS

Of the 702 patients with complete data available, 114 out of 450 patients with epithelial tumors and 31 out of 252 patients with nonepithelial histology were women. Women with epithelial (and not nonepithelial) disease were found to differ significantly from men with respect to younger age, higher rate of thrombocytosis, and longer survival after surgery. The effect of gender on survival of patients with epithelial disease persisted when controlling for age, stage, thrombocytosis, leukocytosis, and anemia with a multivariable analysis. No significant differences in survival were seen among patients with nonepithelial disease with regard to gender, age, or anemia.

CONCLUSIONS

In the absence of other negative prognostic factors, women with epithelial MPM demonstrated a survival advantage. These findings support an aggressive approach to treating MPM including extrapleural pneumonectomy in individuals with favorable prognostic predictors, particularly women with epithelial histology and no other risk factors.

Estrogen receptor alpha 46 is reduced in tamoxifen resistant breast cancer cells and re-expression inhibits cell proliferation and estrogen receptor alpha 66-regulated target gene transcription

Resistance to endocrine therapy is a major clinical problem in breast cancer. The role of ERalpha splice variants in endocrine resistance is largely unknown. We observed reduced protein expression of an N-terminally truncated ERalpha46 in endocrine-resistant LCC2, LCC9, and LY2 compared to MCF-7 breast cancer cells. Transfection of LCC9 and LY2 cells with hERalpha46 partially restored growth inhibition by TAM. Overexpression of hERalpha46 in MCF-7 cells reduced estradiol (E(2))-stimulated endogenous pS2, cyclin D1, nuclear respiratory factor-1 (NRF-1), and progesterone receptor transcription. Expression of oncomiR miR-21 was lower in TAM-resistant LCC9 and LY2 cells compared to MCF-7 cells. Transfection with ERalpha46 altered the pharmacology of E(2) regulation of miR-21 expression from inhibition to stimulation, consistent with the hypothesis that hERalpha46 inhibits ERalpha activity. Established miR-21 targets PTEN and PDCD4 were reduced in ERalpha46-transfected, E(2)-treated MCF-7 cells. In conclusion, ERalpha46 appears to enhance endocrine responses by inhibiting selected ERalpha66 responses.

Biomarkers for early detection of malignant mesothelioma: diagnostic and therapeutic application

Malignant mesothelioma (MM) is a rare and aggressive tumour of the serosal cavities linked to asbestos exposure. Improved detection methods for diagnosing this type of neoplastic disease are essential for an early and reliable diagnosis and treatment. Thus, focus has been placed on finding tumour markers for the non-invasive detection of MM. Recently, some blood biomarkers have been described as potential indicators of early and advanced MM cancers. The identification of tumour biomarkers alone or in combination could greatly facilitate the surveillance procedure for cohorts of subjects exposed to asbestos, a common phenomenon in several areas of western countries.

Gonadotropin-positive pituitary tumors accompanied by ovarian tumors in aging female ERbeta-/- mice

At 2 years of age, 100% (23/23) of ERbeta(-/-) female mice have developed large pituitary and ovarian tumors. The pituitary tumors are gonadotropin-positive and the ovarian tumors are sex cord (less differentiated) and granulosa cell tumors (differentiated and estrogen secreting). No male mice had pituitary tumors and no pituitary or ovarian tumors developed in ERalpha(-/-) mice or in ERalphabeta(-/-) double knockout mice. The tumors have high proliferation indices, are ERalpha-positive, ERbeta-negative, and express high levels of nuclear phospho-SMAD3. Mice with granulosa cell tumors also had hyperproliferative endometria. The cause of the pituitary tumors appeared to be excessive secretion of gonadotropin releasing hormone (GnRH) from the hypothalamus resulting from high expression of NPY. The ovarian phenotype is similar to that seen in mice where inhibin is ablated. The data indicate that ERbeta plays an important role in regulating GnRH secretion. We suggest that in the absence of ERbeta, the proliferative action of FSH/SMAD3 is unopposed and the high proliferation leads to the development of ovarian tumors. The absence of tumors in the ERalphabeta(-/-) mice suggests that tumor development requires the presence of ERalpha.

Benign and Malignant Mesothelial Proliferation

Malignant mesothelioma (MM) is a rare primary malignant tumor of the surface serosal cells. The diagnosis of MM is challenging with a broad differential diagnosis. For many decades, studies have focused on distinguishing MM from other types of cancer; however, benign mesothelial cell hyperplasia, especially in small biopsies, has emerged as a major problem. The features of pleural lesions are somewhat different from peritoneal diseases, and this article primarily focuses on pleural diseases. Thorough interpretation and correlation of clinical, radiologic, and pathologic findings are essential for a correct diagnosis.

Probing the link between oestrogen receptors and oesophageal cancer

BACKGROUND

Human oesophageal carcinoma is considered to be one of the most aggressive malignancies and has a very poor prognosis. The incidence of oesophageal cancer shows a gender bias and is higher in males compared with females, the ratio between males and females varying from 3:1 to 7:1. This sex ratio is not entirely attributable to differences in the prevalence of known risk factors between the sexes. The potential role of oestrogen receptors (ER) in oesophageal cancer has been debated for several years but the significance of the receptors in this cancer remains unknown. Most of the work has been based on immunohistochemistry and has not been validated with other available techniques. The inconsistencies in the published literature on the link between ER expression and oesophageal cancer warrant a thorough evaluation of the potential role of ERs in this malignancy. Even the expression of the two ER isoforms, ERalpha and ERbeta, and its implications for outcome of treatments in histological subtypes of oesophageal tumours is ill defined. The aim of this article is to provide updated information from the available literature on the current status of ER expression in oesophageal cancer and to discuss its potential therapeutic role.

METHODS AND RESULTS

We performed a comprehensive literature search and analysed the results regarding ER expression in oesophageal tumours with special emphasis on expression of different oestrogen receptors and the role of sex hormones in oesophageal cancer. This article also focuses on the significance of the two main ER subtypes and mechanisms underlying the presumed male predominance of this disease.

CONCLUSION

We postulate that differential oestrogen receptor status may be considered a biomarker of poor clinical outcome based on tissue dedifferentiation or advanced stage of the disease. Further, if we can establish the importance of oestrogen and its receptors in the context of oesophageal cancer, then this may lead to a new future direction in the management of this malignancy.