VEGF and VEGF type C play an important role in angiogenesis and lymphangiogenesis in human malignant mesothelioma tumours

Development and validation of a prognostic nomogram for patients with malignant peritoneal mesothelioma

Background

Malignant peritoneal mesothelioma(MPM) is a highly aggressive malignant tumor that originates from peritoneal mesothelial cells. Due to the rarity of MPM, there are few survival prediction models specifically for visualization of malignant peritoneal mesothelioma.

Objective

This study aimed to develop a nomogram for the overall survival of MPM based on the Surveillance, Epidemiology, and End Results (SEER) database and the data of Cangzhou People's Hospital were used for external verification.

Methods

Patients screened from the SEER database were divided into a training group and an internal verification group in a 7:3 ratio, with data from Cangzhou People's Hospital used as the external verification group. Cox proportional hazard regression was utilized to identify significant factors, and nomograms for 6-month, 12-month, and 18-month overall survival were developed. The performance of the nomogram was assessed using consistency index, calibration curve, and K-M curve.

Results

Age, sex, histology, surgery, tumor size, chemotherapy, differentiated and the number of organ metastases were significant risk factors (p<0.05) and were included in the nomogram.The area under the subject worker curve at 6,12,18 months overall survival (AUC) was 0.782,0.784,0.766 for the training group, 0.804,0.791,0.796 for the internal verification group, 0.767,0.749,0.783 for the external verification group. The predicted correction curve was in good agreement with the observed results. The Kaplan-Meier curves of different risk groups showed significant differences.

Conclusion

This study represents the first visual prognostic model of MPM and the initial incorporation of organ metastasis into MPM prognostic factors. The nomograph serves as a reliable tool for clinicians to personalize overall survival prediction and maximize patient benefits by identifying the most effective treatment.

VEGFR2 and CD34 expression associated with longer survival in patients with pleural mesothelioma in the IFCT-GFPC-0701 MAPS phase 3 trial

OBJECTIVES

VEGF/VEGFR autocrine loop is a hallmark of pleural mesothelioma (PM). We thus assayed the prognostic and predictive values of VEGFR-2 [vascular endothelial growth factor receptor 2 or Flk-1] and CD34, a marker of endothelial cells, in samples from patients accrued in the Mesothelioma Avastin Cisplatin Pemetrexed Study ('MAPS', NCT00651456).

MATERIALS AND METHODS

VEGFR2 and CD34 expression were assayed using immunohistochemistry in 333 MAPS patients (74.3%), and their prognostic value was evaluated in terms of overall survival (OS) and progression-free survival (PFS) in univariate and multivariate analyses, before validation by bootstrap methodology.

RESULTS

Positive VEGFR2 or CD34 staining was observed in 234/333 (70.2%) and 322/323 (99.6%) of tested specimens, respectively. VEGFR2 and CD34 staining correlated weakly, yet significantly, with each other (r = 0.36, p < 0.001). High VEGFR2 expression or high CD34 levels were associated with longer OS in PM patients in multivariate analysis (VEGFR2: adjusted [adj.] hazard ratio [HR]: 0.91, 95% confidence interval [CI] [0.88; 0.95], p < 0.001; CD34: adj. HR: 0.86, 95 %CI [0.76; 0.96], p = 0.010), with only high VEGFR2 expression resulting in significantly longer PFS (VEGFR2: adj. HR: 0.96, 95 %CI [0.92; 0.996], p = 0.032). Stability of these results was confirmed using bootstrap procedure. Nevertheless, VEGFR2 expression failed to specifically predict longer survival in bevacizumab-chemotherapy combination trial arm, regardless of whether the VEGFR2 score was combined or not with serum VEGF concentrations.

CONCLUSION

VEGFR2 overexpression independently correlated with longer OS or PFS in PM patients, such biomarker deserving prospective evaluation as stratification variable in future clinical trials.

High-Risk Peritoneal Mesothelioma: Does Metronomic Chemotherapy Have a Role?

Objective

To evaluate the feasibility, tolerance, and efficacy of OMCT (oral metronomic chemotherapy) after CRS + HIPEC for peritoneal mesothelioma in patients with poor prognostic factors: PCI > 20, incomplete CRS, poor performance status, or progression on systemic chemotherapy.

Methods

A retrospective analysis of patients undergoing CRS + HIPEC for peritoneal mesothelioma and receiving OMCT for poor risk factors.

Results

Sixteen patients underwent CRS + HIPEC between 2013 and 2017. The median PCI was 31.5. Complete cytoreduction (CC-0/1) was obtained in 8 patients (50%). All 16 received HIPEC except one patient with baseline renal dysfunction.Thirteen patients had PCI > 20 where only 5 had CC-0/1. Of 8 suboptimal cytoreduction (CC-2/3), 7 received OMCT (6 for progression on chemotherapy and one for mixed histology). Three patients had PCI < 20 and all had CC-0/1 clearance. Only one received OMCT for progression on adjuvant chemotherapy. Patients receiving OMCT for progression on adjuvant chemotherapy (ACT) were in poor PS.The median follow-up was 13.4 months. Five are alive with the disease (three are on OMCT). Six are alive without disease (2 are on OMCT). The mean OS was 24.3 months and the mean DFS was 18 months. Outcomes were similar between CC-0/1 and CC-2/3 groups, OMCT vs no OMCT groups.All patients receiving OMCT for progression on neoadjuvant chemotherapy had better survival (alive at 12, 20, 32, 36 months) compared to those receiving OMCT for progression on the ACT (p = 0.012).

Conclusion

OMCT is a good alternative in high-volume peritoneal mesothelioma with incomplete cytoreduction and progression on chemotherapy. OMCT may improve outcomes in these scenarios when started early.

Diverse and divergent functions of IL-32β and IL-32γ isoforms in the regulation of malignant pleural mesothelioma cell growth and the production of VEGF-A and CXCL8

In this study, we sought to elucidate the roles of the interleukin (IL)-32β and IL-32γ in mesothelioma cell growth, and vascular endothelial growth factor (VEGF)-A and C-X-C motif chemokine ligand 8 (CXCL8) expression. IL-32 elicited a growth-promoting effect against one of the six mesotheliomas lines and exerted diverse regulatory functions in VEGF-A and CXCL8 secretion from mesotheliomas stimulated with or without IL-17A. Retroviral-mediated transduction of mesothelioma lines with IL-32γ resulted in enhanced IL-32β expression, which facilitated or suppressed the in vitro growth, and VEGF-A and CXCL8 expression. Overexpressed IL-32β-augmented growth and VEGF-A and CXCL8 production were mainly mediated through the phosphatidylinositol-3 kinase (PI3K) signaling pathway. On the other hand, overexpressed IL-32β-deceased growth was mediated through mitogen-activated protein kinase (MAPK) pathway. NCI-H2373IL-32γ tumors grew faster than NCI-H2373Neo tumors in a xenograft model, which was associated with increased vascularity. These findings indicate that IL-32 are involved in the regulation of growth and angiogenic factor production in mesotheliomas.

The Chick Embryo Xenograft Model for Malignant Pleural Mesothelioma: A Cost and Time Efficient 3Rs Model for Drug Target Evaluation

Malignant pleural mesothelioma (MPM) has limited treatment options and poor prognosis. Frequent inactivation of the tumour suppressors BAP1, NF2 and P16 may differentially sensitise tumours to treatments. We have established chick chorioallantoic membrane (CAM) xenograft models of low-passage MPM cell lines and protocols for evaluating drug responses. Ten cell lines, representing the spectrum of histological subtypes and tumour suppressor status, were dual labelled for fluorescence/bioluminescence imaging and implanted on the CAM at E7. Bioluminescence was used to assess viability of primary tumours, which were excised at E14 for immunohistological staining or real-time PCR. All MPM cell lines engrafted efficiently forming vascularised nodules, however their size, morphology and interaction with chick cells varied. MPM phenotypes including local invasion, fibroblast recruitment, tumour angiogenesis and vascular remodelling were evident. Bioluminescence imaging could be used to reliably estimate tumour burden pre- and post-treatment, correlating with tumour weight and Ki-67 staining. In conclusion, MPM-CAM models recapitulate important features of the disease and are suitable to assess drug targets using a broad range of MPM cell lines that allow histological or genetic stratification. They are amenable to multi-modal imaging, potentially offering a time and cost-efficient, 3Rs-compliant alternative to rodent xenograft models to prioritise candidate compounds from in vitro studies.

Molecular Alterations in Malignant Pleural Mesothelioma: A Hope for Effective Treatment by Targeting YAP

Malignant pleural mesothelioma is a rare and aggressive neoplasm, which has primarily been attributed to the exposure to asbestos fibers (83% of cases); yet, despite a ban of using asbestos in many countries, the incidence of malignant pleural mesothelioma failed to decline worldwide. While little progress has been made in malignant pleural mesothelioma diagnosis, bevacizumab at first, then followed by double immunotherapy (nivolumab plus ipilumumab), were all shown to improve survival in large phase III randomized trials. The morphological analysis of the histological subtyping remains the primary indicator for therapeutic decision making at an advanced disease stage, while a platinum-based chemotherapy regimen combined with pemetrexed, either with or without bevacizumab, is still the main treatment option. Consequently, malignant pleural mesothelioma still represents a significant health concern owing to poor median survival (12-18 months). Given this context, both diagnosis and therapy improvements require better knowledge of the molecular mechanisms underlying malignant pleural mesothelioma's carcinogenesis and progression. Hence, the Hippo pathway in malignant pleural mesothelioma initiation and progression has recently received increasing attention, as the aberrant expression of its core components may be closely related to patient prognosis. The purpose of this review was to provide a critical analysis of our current knowledge on these topics, the main focus being on the available evidence concerning the role of each Hippo pathway's member as a promising biomarker, enabling detection of the disease at earlier stages and thus improving prognosis.

Lymphatic Tissue Bioengineering for the Treatment of Postsurgical Lymphedema

Lymphedema is characterized by progressive and chronic tissue swelling and inflammation from local accumulation of interstitial fluid due to lymphatic injury or dysfunction. It is a debilitating condition that significantly impacts a patient's quality of life, and has limited treatment options. With better understanding of the molecular mechanisms and pathophysiology of lymphedema and advances in tissue engineering technologies, lymphatic tissue bioengineering and regeneration have emerged as a potential therapeutic option for postsurgical lymphedema. Various strategies involving stem cells, lymphangiogenic factors, bioengineered matrices and mechanical stimuli allow more precisely controlled regeneration of lymphatic tissue at the site of lymphedema without subjecting patients to complications or iatrogenic injuries associated with surgeries. This review provides an overview of current innovative approaches of lymphatic tissue bioengineering that represent a promising treatment option for postsurgical lymphedema.

Immunotherapy for mesothelioma: Moving beyond single immune check point inhibition

Malignant pleural mesothelioma (MPM) is an aggressive neoplasm with low survival rates. Platinum-based chemotherapy has represented the cornerstone of treatment for over a decade, prompting the investigation of new therapeutic strategies both in the early stage of the disease and in the advanced setting. The advent of immune check-point inhibitors (ICIs) has recently revamped the enthusiasm for using immunotherapy also in MPM. However, results from first clinical trials using single immune check-point inhibition have been conflicting, and this may be mainly attributed to the lack of specific biomarkers as well as to intra- and inter- patient heterogeneity. The phase III Checkmate743 firstly demonstrated the superiority of an ICI combination (nivolumab plus ipilimumab) over chemotherapy in the first-line treatment of unresectable MPM, leading to FDA approval of this regimen and showing that moving beyond single immune check point inhibition might be a successful strategy to overcome resistance in the majority of MPM patients. In this review, we describe the emerging immunotherapy strategies for the treatment of MPM. We also discuss how refining the approach in pre-clinical studies towards a more holistic perspective (which takes into account not only genetic but also pathophysiological vulnerabilities) and strengthening multi-institutional collaboration in clinical trials is finally helping the clinical development of immunotherapy in MPM.

Oncological Frontiers in the Treatment of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare malignancy characterized by very poor prognosis and lack of treatment options. Immunotherapy has rapidly emerged as an effective tool for MPM, particularly for tumors of non-epithelioid histology. At the same time, comprehensive genomic sequencing may open the way to new-generation targeted-drugs able to hit specific MPM molecular vulnerabilities. These innovations will possibly enrich, but also dramatically complicate, the elucidation of treatment algorithms. Multidisciplinary integration is urgently needed.

Pathological Characterization of Tumor Immune Microenvironment (TIME) in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare and highly aggressive disease that arises from pleural mesothelial cells, characterized by a median survival of approximately 13-15 months after diagnosis. The primary cause of this disease is asbestos exposure and the main issues associated with it are late diagnosis and lack of effective therapies. Asbestos-induced cellular damage is associated with the generation of an inflammatory microenvironment that influences and supports tumor growth, possibly in association with patients' genetic predisposition and tumor genomic profile. The chronic inflammatory response to asbestos fibers leads to a unique tumor immune microenvironment (TIME) composed of a heterogeneous mixture of stromal, endothelial, and immune cells, and relative composition and interaction among them is suggested to bear prognostic and therapeutic implications. TIME in MPM is known to be constituted by immunosuppressive cells, such as type 2 tumor-associated macrophages and T regulatory lymphocytes, plus the expression of several immunosuppressive factors, such as tumor-associated PD-L1. Several studies in recent years have contributed to achieve a greater understanding of the pathogenetic mechanisms in tumor development and pathobiology of TIME, that opens the way to new therapeutic strategies. The study of TIME is fundamental in identifying appropriate prognostic and predictive tissue biomarkers. In the present review, we summarize the current knowledge about the pathological characterization of TIME in MPM.

Old but gold: the role of drug combinations in improving response to immune check-point inhibitors in thoracic malignancies beyond NSCLC

The introduction of immune checkpoint inhibitors (ICIs) in non-oncogene addicted non-small cell lung cancer (NSCLC) has revolutionized the treatment scenario and led to a meaningful improvement in patient prognosis. Disappointingly, the success of ICI therapy in NSCLC has not been fully replicated in other thoracic malignancies as small cell lung cancer (SCLC), malignant pleural mesothelioma (MPM), and thymic epithelial tumors (TETs), due to the peculiar biological features of these disease and to the difficulties in the conduction of well-designed, biomarker-driven clinical trials. Therefore, combination strategies of ICIs plus conventional therapies (either chemotherapy, alternative ICIs or targeted agents) have been implemented. Although first approvals of ICI therapy have been recently granted in SCLC and MPM (in combination with chemotherapy and different ICIs), results remain somewhat modest and limited to a small proportion of patients. This work reviews the trial results of ICI therapy in mesothelioma, SCLC, and TETs and discusses the potential of combining ICIs with old drugs.

Syndecan-1 Overexpressing Mesothelioma Cells Inhibit Proliferation, Wound Healing, and Tube Formation of Endothelial Cells

Simple Summary

The transmembrane proteoglycan syndecan-1 (SDC-1) is an important mediator of cell-matrix interactions. The heparan sulfate side-chains of SDC-1 can bind to a multitude of growth factors, cytokines, and chemokines, thereby regulating a plethora of physiological and pathological processes, including angiogenesis. The extracellular region of SDC-1 can be released from the cell surface by the action of sheddases including matrix metalloproteinase-7 and 9, resulting in a soluble protein that is still active and can act as a competitive activator or inhibitor of the cell surface receptor. Accelerated shedding and loss of cell surface SDC-1 is associated with epithelial to mesenchymal transition (EMT) and achievement of a more invasive phenotype in malignant mesothelioma (MM). Transfection with SDC-1 reverts the morphology in epithelioid direction and inhibits the proliferation and migration of MM cells. This study aimed to investigate the role of SDC-1 in angiogenesis. We demonstrate that overexpression and silencing of SDC-1 alters the secretion of angiogenic proteins in MM cells. Upon SDC-1 overexpression, several factors collectively inhibit the proliferation, wound closure, and tube formation of endothelial cells, whereas SDC-1 silencing only affects wound healing.

Abstract

Malignant mesothelioma (MM) is an aggressive tumor of the serosal cavities. Angiogenesis is important for mesothelioma progression, but so far, anti-angiogenic agents have not improved patient survival. Our hypothesis is that better understanding of the regulation of angiogenesis in this tumor would largely improve the success of such a therapy. Syndecan-1 (SDC-1) is a transmembrane heparan sulfate proteoglycan that acts as a co-receptor in various cellular processes including angiogenesis. In MM, the expression of SDC-1 is generally low but when present, SDC-1 associates to epithelioid differentiation, inhibition of tumor cell migration and favorable prognosis, meanwhile SDC-1 decrease deteriorates the prognosis. In the present study, we studied the effect of SDC-1 overexpression and silencing on MM cells ability to secrete angiogenic factors and monitored the downstream effect of SDC-1 modulation on endothelial cells proliferation, wound healing, and tube formation. This was done by adding conditioned medium from SDC-1 transfected and SDC-1 silenced mesothelioma cells to endothelial cells. Moreover, we investigated the interplay and molecular functional changes in angiogenesis in a co-culture system and characterized the soluble angiogenesis-related factors secreted to the conditioned media. We demonstrated that SDC-1 over-expression inhibited the proliferation, wound healing, and tube formation of endothelial cells. This effect was mediated by a multitude of angiogenic factors comprising angiopoietin-1 (Fold change ± SD: 0.65 ± 0.07), FGF-4 (1.45 ± 0.04), HGF (1.33 ± 0.07), NRG1-β1 (1.35 ± 0.08), TSP-1 (0.8 ± 0.02), TIMP-1 (0.89 ± 0.01) and TGF-β1 (1.35 ± 0.01). SDC-1 silencing increased IL8 (1.33 ± 0.06), promoted wound closure, but did not influence the tube formation of endothelial cells. Pleural effusions from mesothelioma patients showed that Vascular Endothelial Growth Factor (VEGF) levels correlate to soluble SDC-1 levels and have prognostic value. In conclusion, SDC-1 over-expression affects the angiogenic factor secretion of mesothelioma cells and thereby inhibits endothelial cells proliferation, tube formation, and wound healing. VEGF could be used in prognostic evaluation of mesothelioma patients together with SDC-1.

Circulating biomarkers in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive tumor strictly connected to asbestos exposure. Prognosis is dismal as diagnosis commonly occurs in advanced stage. Radiological screenings have not proven to be effective and also pathological diagnosis may be challenging. In the era of precision oncology, validation of robust non-invasive biomarkers for screening of asbestos-exposed individuals, assessment of prognosis and prediction of response to treatments remains an important unmet clinical need. This review provides an overview on current understanding and possible applications of liquid biopsy in MPM, mostly focused on the utility as diagnostic and prognostic test.

Analysis of angiogenic and stromal biomarkers in a large malignant mesothelioma cohort

BACKGROUND

Malignant mesothelioma (MM) is an aggressive malignancy of the pleura and other mesothelial membranes. Agents targeting vascular endothelial growth factor (VEGF) such as bevacizumab; and multi-kinase inhibitors such as nintedanib [angiokinase inhibitor of VEGF, platelet-derived growth factor (PDGF) receptor and fibroblast growth factor receptor (FGFR)] have recently demonstrated efficacy in MM.

METHODS

Tissue microarrays (TMAs) were created from formalin-fixed, paraffin-embedded tissue samples obtained from 326 patients with MM who were treated surgically. PDGF-CC, FGFR-1, VEGF and CD31 expression were analysed by immunohistochemical (IHC) staining. The H-score method assigned a score of 0-300 to each sample, based on the percentage of cells stained at different intensities. CD31 was evaluated via Chalkley's method to evaluate microvessel density. We evaluated the association between expression of the biomarkers, clinicopathological factors and outcomes, in patients with MM.

RESULTS

CD31 high (≥5) was seen in only 31/302 (10.3%) irrespective of histology. PDGF-CC high (≥150) was seen in 203 /310 (65%) of all samples. VEGF high (≥80) was seen in 219/322 (68%) of all MM with 143/209 (68%) of epithelioid histology. FGFR-1 high (≥40) was seen in 127/310 (41%) of all MM. There was no association of VEGF and FGFR-1 IHC with survival nor differences between histological subtypes. There was a non-significant trend towards poorer survival in epithelioid tumours with increased PDGF-CC expression (OS 18.5 vs 13.2 months; HR 0.7928; 95% CI 0.5958 to 1.055, P = 0.1110). High CD31 score was associated with significantly poorer survival (OS 12 vs 8.6 months; HR 0.48; 95% CI 0.2873 to 0.7941, P = 0.0044). Of the 31 patients with high CD31 scores; 23/31 (74%) were also high for PDGF-CC and 20/31 (64%) with high VEGF scores. CD31 was found to be an independent prognostic factor in multivariate analysis (HR 1.540; 95% CI 1.018 to 2.330; p = 0.041).

CONCLUSIONS

High CD31 was an independent poor prognostic factor and high PDGF-CC expression was associated with poor survival in MM. Abrogating these pathways may have prognostic implications.

Bevacizumab plus cisplatin/pemetrexed then bevacizumab alone for unresectable malignant pleural mesothelioma: A Japanese safety study

Aims

Malignant pleural mesothelioma (MPM) is an aggressive malignancy with poor prognosis and limited treatment options. Cisplatin plus pemetrexed is the only approved first‐line treatment for patients with unresectable MPM. Recently, promising outcomes were observed with first‐line bevacizumab combined with cisplatin/pemetrexed, leading to the recommendation of this regimen as a first‐line treatment option for patients with MPM. Bevacizumab plus cisplatin/pemetrexed has been shown to be safe and effective in non–small cell lung cancer, however, there are no efficacy or safety data in Japanese patients with MPM treated with this regimen. We conducted a multicenter study to evaluate tolerability and safety for Japanese patients with chemotherapy‐naïve, unresectable MPM.

Methods

Eligible patients (n = 7) received bevacizumab plus cisplatin/pemetrexed (up to six cycles), then single‐agent bevacizumab until disease progression or onset of unacceptable adverse events (AEs), according to the 3+3 design analogy.

Results

One patient (14.3%) reported an AE (gastric ulcer) meeting tolerability criteria. All patients experienced gastrointestinal disorders, including nausea (grade 1/2 only, n = 6, 85.7%) and constipation (grade 1/2 only, n = 5, 71.4%). Five patients (71.4%) had grade 3 hypertension. Two patients discontinued treatment due to gastric ulcer (n = 1) and proteinuria (n = 1). At data cut‐off, four patients had stable disease, two had partial response and one had non‐complete response/non‐progressive disease due to the absence of target lesions.

Conclusions

Bevacizumab plus cisplatin/pemetrexed then bevacizumab was well tolerated in Japanese patients with MPM.

Structure-activity relationship studies of indolin-2-one derivatives as vascular endothelial growth factor receptor inhibitors and anticancer agents

Angiogenesis is a requirement for the growth of cancer cells. The family of vascular endothelial growth factor receptors (VEGFRs) is the main target in metastasis. Indolin-2-one is proved to be an essential scaffold of antiangiogenic drugs. Sunitinib is the first oral indolin-2-one derivative marketed as a VEGFR inhibitor in the treatment of renal cell carcinoma and gastrointestinal stromal tumors. Therefore, novel compounds possessing the scaffold of sunitinib were designed and synthesized by different researchers to improve the anticancer activity, bioavailability, and solubility, and to decrease the toxicity of sunitinib. In this comprehensive review, the structure-activity relationship of different indolin-2-one analogs as VEGFR inhibitors is discussed. It has been observed that the indolin-2-one core is necessary for the inhibition of VEGFRs. It was determined that substitutions at C-3 of the oxindole ring play an important role in their antiangiogenic and anticancer activities.

Genomics and Functional Genomics of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare, aggressive cancer of the mesothelial cells lining the pleural surface of the chest wall and lung. The etiology of MPM is strongly associated with prior exposure to asbestos fibers, and the median survival rate of the diagnosed patients is approximately one year. Despite the latest advancements in surgical techniques and systemic therapies, currently available treatment modalities of MPM fail to provide long-term survival. The increasing incidence of MPM highlights the need for finding effective treatments. Targeted therapies offer personalized treatments in many cancers. However, targeted therapy in MPM is not recommended by clinical guidelines mainly because of poor target definition. A better understanding of the molecular and cellular mechanisms and the predictors of poor clinical outcomes of MPM is required to identify novel targets and develop precise and effective treatments. Recent advances in the genomics and functional genomics fields have provided groundbreaking insights into the genomic and molecular profiles of MPM and enabled the functional characterization of the genetic alterations. This review provides a comprehensive overview of the relevant literature and highlights the potential of state-of-the-art genomics and functional genomics research to facilitate the development of novel diagnostics and therapeutic modalities in MPM.

Hypoxic tumor microenvironment: Implications for cancer therapy

IMPACT STATEMENT

Hypoxia contributes to tumor aggressiveness and promotes growth of many solid tumors that are often resistant to conventional therapies. In order to achieve successful therapeutic strategies targeting different cancer types, it is necessary to understand the molecular mechanisms and signaling pathways that are induced by hypoxia. Aberrant tumor vasculature and alterations in cellular metabolism and drug resistance due to hypoxia further confound this problem. This review focuses on the implications of hypoxia in an inflammatory TME and its impact on the signaling and metabolic pathways regulating growth and progression of cancer, along with changes in lymphangiogenic and angiogenic mechanisms. Finally, the overarching role of hypoxia in mediating therapeutic resistance in cancers is discussed.

Antiangiogeneic Strategies in Mesothelioma

There is a strong rationale for inhibiting angiogenesis in mesothelioma. Vascular endothelial growth factor (VEGF) is an autocrine growth factor in mesothelioma and a potent mitogen for mesothelial cells. Further, the abnormal tumor vasculature promotes raised interstitial pressure and hypoxia, which may be detrimental to both penetration and efficacy of anticancer agents. Antiangiogenic agents have been trialed in mesothelioma for close to two decades, with early phase clinical trials testing vascular targeting agents, the VEGF-A targeting monoclonal antibody bevacizumab, and numerous tyrosine kinase inhibitors, many with multiple targets. None of these have shown efficacy which has warranted further development as single agents in any line of therapy. Whilst a randomized phase II trial combining the multitargeted tyrosine kinase inhibitor nintedanib with platinum/pemetrexed chemotherapy was positive, these results were not confirmed in a subsequent phase III study. The combination of cisplatin and pemetrexed with bevacizumab, in appropriately selected patients, remains the only anti-angiogenic combination showing efficacy in mesothelioma. Extensive efforts to identify biomarkers of response have not yet been successful.

Chemotherapy options versus "novel" therapies: how should we treat patients with malignant pleural mesothelioma

Today there are several options for the treatment of patients with malignant pleural mesothelioma (MPM). The therapeutic arsenal has expanded from only chemotherapy with or without surgery in selected cases to a variety of new compounds that target the malignant cell or its micro-environment. Immunotherapy has been the latest achievement and now single arm and randomized studies are being presented. A renewed interest has occurred in the combination of surgery, chemotherapy and radiation therapy. In this review we present the available data on previous and running studies and try to give a recommendation how to select the best patient for the most optimal therapy.

The role of tumor-derived exosomes in tumor angiogenesis and tumor progression

Exosomes, belonging to the group of extracellular bodies, are released by healthy as well as cancerous cells and serve as a communication pathway. Tumor-derived exosomes (TEX) possess the capacity to reprogram the function of normal cells owing to their genetic and molecular cargo. Such exosomes target endothelial cells (among others) in the tumor microenvironment to promote angiogenesis. Blood supply is essential in solid tumor growth and metastasis. The potential of pro-angiogenic changes is enhanced by an increased amount of circulating tumor-derived exosomes in the body fluids of cancer patients. A vascular network is important, since the proliferation, as well as the metastatic spread of cancer cells depends on an adequate supply of oxygen and nutrients, and the removal of waste products. New blood vessels and lymphatic vessels are formed through processes called angiogenesis and lymphangiogenesis, respectively. Angiogenesis is regulated by both activator and inhibitor molecules. Thousands of patients have received anti-angiogenic therapy to date. Despite their theoretical efficacy, anti-angiogenic treatments have not proved beneficial in terms of long-term survival. Tumor-derived exosomes carrying pro-angiogenic factors might be a target for new anti-cancer therapy.

Redefining malignant pleural mesothelioma types as a continuum uncovers immune-vascular interactions

BACKGROUND

Malignant Pleural Mesothelioma (MPM) is an aggressive disease related to asbestos exposure, with no effective therapeutic options.

METHODS

We undertook unsupervised analyses of RNA-sequencing data of 284 MPMs, with no assumption of discreteness. Using immunohistochemistry, we performed an orthogonal validation on a subset of 103 samples and a biological replication in an independent series of 77 samples.

FINDINGS

A continuum of molecular profiles explained the prognosis of the disease better than any discrete model. The immune and vascular pathways were the major sources of molecular variation, with strong differences in the expression of immune checkpoints and pro-angiogenic genes; the extrema of this continuum had specific molecular profiles: a "hot" bad-prognosis profile, with high lymphocyte infiltration and high expression of immune checkpoints and pro-angiogenic genes; a "cold" bad-prognosis profile, with low lymphocyte infiltration and high expression of pro-angiogenic genes; and a "VEGFR2+/VISTA+" better-prognosis profile, with high expression of immune checkpoint VISTA and pro-angiogenic gene VEGFR2. We validated the gene expression levels at the protein level for a subset of five selected genes belonging to the immune and vascular pathways (CD8A, PDL1, VEGFR3, VEGFR2, and VISTA), in the validation series, and replicated the molecular profiles as well as their prognostic value in the replication series.

INTERPRETATION

The prognosis of MPM is best explained by a continuous model, which extremes show specific expression patterns of genes involved in angiogenesis and immune response.

Involvement of Heparanase in the Pathogenesis of Mesothelioma: Basic Aspects and Clinical Applications

Background

Mammalian cells express a single functional heparanase, an endoglycosidase that cleaves heparan sulfate and thereby promotes tumor metastasis, angiogenesis, and inflammation. Malignant mesothelioma is highly aggressive and has a poor prognosis because of the lack of markers for early diagnosis and resistance to conventional therapies. The purpose of this study was to elucidate the mode of action and biological significance of heparanase in mesothelioma and test the efficacy of heparanase inhibitors in the treatment of this malignancy.

Methods

The involvement of heparanase in mesothelioma was investigated by applying mouse models of mesothelioma and testing the effect of heparanase gene silencing (n = 18 mice per experiment; two different models) and heparanase inhibitors (ie, PG545, defibrotide; n = 18 per experiment; six different models). Synchronous pleural effusion and plasma samples from patients with mesothelioma (n = 35), other malignancies (12 non-small cell lung cancer, two small cell lung carcinoma, four breast cancer, three gastrointestinal cancers, two lymphomas), and benign effusions (five patients) were collected and analyzed for heparanase content (enzyme-linked immunosorbent assay). Eighty-one mesothelioma biopsies were analyzed by H-Score for the prognostic impact of heparanase using immunohistochemistry. All statistical tests were two-sided.

Results

Mesothelioma tumor growth, measured by bioluminescence or tumor weight at termination, was markedly attenuated by heparanase gene silencing (P = .02) and by heparanase inhibitors (PG545 and defibrotide; P < .001 and P = .01, respectively). A marked increase in survival of the mesothelioma-bearing mice (P < .001) was recorded. Heparanase inhibitors were more potent in vivo than conventional chemotherapy. Clinically, heparanase levels in patients' pleural effusions could distinguish between malignant and benign effusions, and a heparanase H-score above 90 was associated with reduced patient survival (hazard ratio = 1.89, 95% confidence interval = 1.09 to 3.27, P = .03).

Conclusions

Our results imply that heparanase is clinically relevant in mesothelioma development. Given these preclinical and clinical data, heparanase appears to be an important mediator of mesothelioma, and heparanase inhibitors are worthy of investigation as a new therapeutic modality in mesothelioma clinical trials.

Phase II Trial of Cediranib in Combination With Cisplatin and Pemetrexed in Chemotherapy-Naïve Patients With Unresectable Malignant Pleural Mesothelioma (SWOG S0905)

PURPOSE

Antiangiogenic agents combined with chemotherapy have efficacy in the treatment of unresectable malignant pleural mesothelioma (MPM). Cediranib (AstraZeneca, Cheshire, United Kingdom), a vascular endothelial growth factor receptor and platelet-derived growth factor receptor inhibitor, demonstrated therapeutic potential in a prior phase I trial. We evaluated a phase II trial for efficacy.

PATIENTS AND METHODS

SWOG S0905 (ClinicalTrials.gov identifier: NCT01064648) randomly assigned cediranib or placebo with platinum-pemetrexed for six cycles followed by maintenance cediranib or placebo in unresectable chemotherapy-naïve patients with MPM of any histologic subtype. Primary end point was Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 progression-free survival (PFS). Secondary end points included overall survival, PFS by modified RECIST v1.1, response (modified RECIST and RECIST v1.1), disease control, and safety/toxicity. The trial was designed to detect a difference in RECIST v1.1 PFS at the one-sided 0.1 level using a stratified log-rank test.

RESULTS

Ninety-two eligible patients were enrolled (75% epithelioid and 25% biphasic or sarcomatoid). The cediranib arm had more grade 3 and 4 diarrhea, dehydration, hypertension, and weight loss. Cediranib improved PFS by RECIST v1.1 (hazard ratio, 0.71; 80% CI, 0.54 to 0.95; P = .062; 7.2 months v 5.6 months) and increased modified RECIST v1.1 response (50% v 20%; P = .006). By modified RECIST v1.1, cediranib numerically increased PFS (hazard ratio, 0.77; 80% CI, 0.59 to 1.02; P = .12; median, 6.9 months v 5.6 months). No significant difference in overall survival was observed.

CONCLUSION

The addition of cediranib to platinum-pemetrexed improved PFS by RECIST v1.1 and response rate by modified RECIST in patients with unresectable MPM. Whereas adding antiangiogenics to chemotherapy has been a successful strategy for some patients, the cediranib toxicity profile and small incremental survival benefit precludes additional development in MPM.

Two Birds, One Stone: Double Hits on Tumor Growth and Lymphangiogenesis by Targeting Vascular Endothelial Growth Factor Receptor 3

Vascular endothelial growth factor receptor 3 (VEGFR3) has been known for its involvement in tumor-associated lymphangiogenesis and lymphatic metastasis. The VEGFR3 signaling is stimulated by its main cognate ligand, vascular endothelial growth factor C (VEGF-C), which in turn promotes tumor progression. Activation of VEGF-C/VEGFR3 signaling in lymphatic endothelial cells (LECs) was shown to enhance the proliferation of LECs and the formation of lymphatic vessels, leading to increased lymphatic metastasis of tumor cells. In the past decade, the expression and pathological roles of VEGFR3 in tumor cells have been described. Moreover, the VEGF-C/VEGFR3 axis has been implicated in regulating immune tolerance and suppression. Therefore, the inhibition of the VEGF-C/VEGFR3 axis has emerged as an important therapeutic strategy for the treatment of cancer. In this review, we discuss the current findings related to VEGF-C/VEGFR3 signaling in cancer progression and recent advances in the development of therapeutic drugs targeting VEGF-C/VEGFR3.

Quantitative mass spectrometry to identify protein markers for diagnosis of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a devastating malignancy with a prognosis of <12 months. Even with bans on the use of asbestos in most Western countries, the incidence is still increasing due to the long latency periods between exposure and development of the disease. Diagnosis is often delayed due to invasive biopsies and lack of distinguishable markers. Patients frequently present with pleural effusions months to years before a radiologically detectable mass appears. This study aimed to investigate the proteome of pleural effusions taken from patients with MPM, adenocarcinoma and benign conditions in an attempt to identify a biomarker for early diagnosis. We identified several proteins that may be possible targets and warrant further investigation. Due to the predominance of up regulated proteins involved in VEGF signalling in MPM, we analysed VEGFA levels in effusions and found a strong correlation between VEGFA levels and survival in MPM.

Biodistribution and Tumor Uptake of 67Ga-Nimotuzumab in a Malignant Pleural Mesothelioma Xenograft

Malignant pleural mesothelioma (MPM) is the most common tumor of the pulmonary pleura. It is a rare and aggressive malignancy, generally associated with continuous occupational exposure to asbestos. Only a multimodal-approach to treatment, based on surgical resection, chemotherapy and/or radiation, has shown some benefits. However, the survival rate remains low. Nimotuzumab (h-R3), an anti-EGFR (epidermal growth factor receptor) humanized antibody, is proposed as a promising agent for the treatment of MPM. The aim of this research was to implement a procedure for nimotuzumab radiolabeling to evaluate its biodistribution and affinity for EGF (epidermal growth factor) receptors present in a mesothelioma xenograft. Nimotuzumab was radiolabeled with 67Ga; radiolabel efficiency, radiochemical purity, serum stability, and biodistribution were evaluated. Biodistribution and tumor uptake imaging studies by microSPECT/CT in mesothelioma xenografts revealed constant nimotuzumab uptake at the tumor site during the first 48 h after drug administration. In vivo studies using MPM xenografts showed a significant uptake of this radioimmunoconjugate, which illustrates its potential as a biomarker that could promote its theranostic use in patients with MPM.

Correlation of Vascular Endothelial Growth Factor subtypes and their receptors with melanoma progression: A next-generation Tissue Microarray (ngTMA) automated analysis

INTRODUCTION

Finding new markers to assess prognosis of melanoma without the necessity to perform a surgical interventions is an important goal in melanoma research. The current study aimed to assess the correlation of clinical course and prognosis of primary and metastatic melanoma with expression of VEGF family and their receptors.

METHODS

A ngTMA block was made from the randomly selected paraffin tissue blocks of the patients with melanocytic nevi, primary and metastatic melanoma. Then sections cut from ngTMA-block were immunohistochemically stained with proper antibodies. Expression of these proteins was investigated using automated image analysis and compared among the study groups.

RESULTS

We analyzed the tissue of 238 patients with following diagnoses: 101 (42.4%) with a diagnosis of nevus, 86 (36.1%) Malignant melanoma and 51 (21.4%) metastasis. Median follow-up time for the malignant lesions was 5.71 years. Among the tested antigen, VEGF-C (p = 0.016), VEGF-R2 (p<0.001) and VEGF-R3 (p = 0.002) were significantly higher expressed in the metastatic tissues. When these scores were assessed in multiple regression models, the only independent factor linked to patient's diagnosis was VEGF-R2 (p<0.001). In addition, groups of highly correlated variables (VEGF-C and VEGF-R3, VEGF-A and VEGF-R1) were found to form separate sub-clusters. On the other side, high values of VEGF-C were associated with both overall and disease-free survival with a statically significant HR of 2.76 (95% CI: 1.27, 5.98; p = 0.01) and 2.82 (95%CI: 1.62, 4.91; p<0.001), respectively.

CONCLUSIONS

This study shows that VEGF-C and VEGF-R2 might represent new prognostic marker in MM. However, further prospective studies are warranted to test their real efficacy as a prognostic marker.

Curcumin induces apoptosis and inhibits angiogenesis in murine malignant mesothelioma

Malignant pleural mesothelioma (MPM) is a rare form of cancer that is associated with asbestos exposure. Unfortunately, current therapies have limited efficacy. Previous studies have indicated that curcumin exerts antiproliferative and antitumor effects, and has low toxicity. The present study aimed to evaluate the anticancer effects of curcumin on the RN5 MPM cell line. The inhibitory effects of curcumin on cell viability were determined using the sulforhodamine B assay. In addition, cell cycle progression was analyzed by propidium iodide (PI) staining and flow cytometry, and curcumin‑induced apoptosis was measured by Annexin V/PI double staining. The translocation of apoptosis-inducing factor (AIF) was assessed by western blotting and immunofluorescence, and the expression levels of the phosphoinositide 3-kinase (PI3K)-AKT serine/threonine kinase (Akt)‑mammalian target of rapamycin (mTOR) signaling pathway proteins and mitochondria-associated proteins were evaluated by western blotting. In vivo antitumor effects were evaluated in a subcutaneous murine model. Briefly, tumors were harvested from the mice, and immunohistochemistry was conducted to evaluate cell proliferation, apoptosis and angiogenesis. The results indicated that curcumin inhibited RN5 cell viability and induced apoptotic cell death. In addition the findings suggested that curcumin-induced cell apoptosis occurred via the mitochondrial pathway, and caspase‑independent and AIF-dependent pathways. Further analysis revealed that curcumin may act as a PI3K-Akt-mTOR signaling pathway inhibitor by downregulating PI3K, p-Akt, p-mTOR and p-p70 ribosomal protein S6 kinase. Furthermore, curcumin inhibited tumor angiogenesis in vivo. In conclusion, curcumin may be potent enough to be developed as a novel therapeutic agent for the treatment of MPM.

New Perspectives on Diagnosis and Therapy of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare, but severe form of cancer, with an incidence that varies significantly within and among different countries around the world. It develops in about one to two persons per million of the general population, leading to thousands of deaths every year worldwide. To date, the MPM is mostly associated with occupational asbestos exposure. Asbestos represents the predominant etiological factor, with approximately 70% of cases of MPM with well-documented occupational exposure to asbestos, with the exposure time, on average greater than 40 years. Environmental exposure to asbestos is increasingly becoming recognized as a cause of mesothelioma, together with gene mutations. The possible roles of other cofactors, such as viral infection and radiation exposure, are still debated. MPM is a fatal tumor. This cancer arises during its early phase without clinical signs. Consequently, its diagnosis occurs at advanced stages. Standard clinical therapeutic approaches include surgery, chemo- and radiotherapies. Preclinical and clinical researches are making great strides in the field of this deadly disease, identifying new biomarkers and innovative therapeutic approaches. Among the newly identified markers and potential therapeutic targets, circulating microRNAs and the Notch pathway represent promising avenues that could result in the early detection of the tumor and novel therapeutic approaches.

Heterogeneous Contributing Factors in MPM Disease Development and Progression: Biological Advances and Clinical Implications

Malignant pleural mesothelioma (MPM) tumors are remarkably aggressive and most patients only survive for 5–12 months; irrespective of stage; after primary symptoms appear. Compounding matters is that MPM remains unresponsive to conventional standards of care; including radiation and chemotherapy. Currently; instead of relying on molecular signatures and histological typing; MPM treatment options are guided by clinical stage and patient characteristics because the mechanism of carcinogenesis has not been fully elucidated; although about 80% of cases can be linked to asbestos exposure. Several molecular pathways have been implicated in the MPM tumor microenvironment; such as angiogenesis; apoptosis; cell-cycle regulation and several growth factor-related pathways predicted to be amenable to therapeutic intervention. Furthermore, the availability of genomic data has improved our understanding of the pathobiology of MPM. The MPM genomic landscape is dominated by inactivating mutations in several tumor suppressor genes; such as CDKN2A; BAP1 and NF2. Given the complex heterogeneity of the tumor microenvironment in MPM; a better understanding of the interplay between stromal; endothelial and immune cells at the molecular level is required; to chaperone the development of improved personalized therapeutics. Many recent advances at the molecular level have been reported and several exciting new treatment options are under investigation. Here; we review the challenges and the most up-to-date biological advances in MPM pertaining to the molecular pathways implicated; progress at the genomic level; immunological progression of this fatal disease; and its link with developmental cell pathways; with an emphasis on prognostic and therapeutic treatment strategies.

Cisplatin and Pemetrexed Activate AXL and AXL Inhibitor BGB324 Enhances Mesothelioma Cell Death from Chemotherapy

Reactive oxygen species (ROS) can promote or inhibit tumorigenesis. In mesothelioma, asbestos exposure to serous membranes induces ROS through iron content and chronic inflammation, and ROS promote cell survival signaling in mesothelioma. Moreover, a current chemotherapy regimen for mesothelioma consisting of a platinum and antifolate agent combination also induce ROS. Mesothelioma is notoriously chemotherapy-resistant, and we propose that ROS induced by cisplatin and pemetrexed may promote cell survival signaling pathways, which ultimately may contribute to chemotherapy resistance. In The Cancer Genome Atlas datasets, we found AXL kinase expression is relatively high in mesothelioma compared to other cancer samples. We showed that ROS induce the phosphorylation of AXL, which was blocked by the selective inhibitor BGB324 in VMC40 and P31 mesothelioma cells. We also showed that cisplatin and pemetrexed induce the phosphorylation of AXL and Akt, which was also blocked by BGB324 as well as by N-acetylcysteine antioxidant. AXL knockdown in these cells enhances sensitivity to cisplatin and pemetrexed. Similarly, AXL inhibitor BGB324 also enhances sensitivity to cisplatin and pemetrexed. Finally, higher synergy was observed when cells were pretreated with BGB324 before adding chemotherapy. These results demonstrate cisplatin and pemetrexed induce ROS that activate AXL, and blocking AXL activation enhances the efficacy of cisplatin and pemetrexed. These results suggest AXL inhibition combined with the current chemotherapy regimen may represent an effective strategy to enhance the efficacy of chemotherapy in mesothelioma. This is the first study, to our knowledge, on chemotherapy-induced activation of AXL and cell survival pathways associated with ROS signaling.

Biomarker-Integrated Neoadjuvant Dasatinib Trial in Resectable Malignant Pleural Mesothelioma

INTRODUCTION

Window of opportunity trials in malignant pleural mesothelioma (MPM) are challenging but can yield important translational information about a novel agent.

METHODS

We treated patients with MPM (N = 24) with 4 weeks of oral dasatinib followed by surgery with or without radiotherapy and then an optional 2 years of maintenance dasatinib. The primary end point was biomarker modulation of phosphorylated (p) Src^Tyr419.

RESULTS

For all patients, the median progression-free survival (PFS) was 7.5 months and the median overall survival was 19.1 months. No significant responses were seen after 4 weeks of dasatinib therapy; however, modulation of median p-Src^Tyr419 immunohistochemistry (IHC) scores was seen: the median pretreatment score was 70 (interquartile range 37.5-110), and the median posttreatment score was 41.9 (interquartile range 4.2-60) (p = 0.004). A decrease in p-Src^Tyr419 levels after dasatinib correlated with improved median PFS (6.9 months versus 0.94 months [p = 0.03]), suggesting that p-Src^Tyr419 is a viable pharmacodynamic biomarker for dasatinib in MPM. Platelet-derived growth factor receptor (PDGFR) pathway analysis correlated high PDGFR beta [PDGFRB) level (in the cytoplasm [hazard ratio] (HR) = 2.54, p = 0.05], stroma [HR = 2.79, p = 0.03], and nucleus [HR = 6.79, p = 0.023]) with a shorter PFS. Low (less than the median) cytoplasmic p-PDGFR alpha IHC levels were predictive of a decrease in positron emission tomography/computed tomography standard uptake values levels after dasatinib therapy (p = 0.04), whereas higher-than-median IHC scores of PDGFRB (cytoplasmic [HR = 2.8, p = 0.03] and nuclear [HR = 6.795, p = 0.02]) were correlated with rising standard uptake values levels.

CONCLUSIONS

In conclusion, there was no significant efficacy signal, and dasatinib monotherapy will not continue to be studied in MPM. However, our study demonstrated that PDGFR subtypes (platelet-derived growth factor receptor alpha and PDGFRB) may have differential roles in prognosis and resistance to antiangiogenic tyrosine kinase inhibitors and are important potential therapeutic targets that require further investigation.

The importance of serum and pleural fluid level of vascular endothelial growth factor (VEGF) and VEGF fluid/serum ratio in the differential diagnosis of malignant mesothelioma-related pleural effusion

Aim of the study

Vascular endothelial growth factor (VEGF) is one of the parameters that has been studied in differential diagnosis of malignant fluids. This study is aimed at evaluate applicability of serum, fluid VEGF level and fluid to serum VEGF ratio in the diagnosis of malignant pleural mesothelioma (MPM).

Material and methods

The patients with pleural effusion over age of 18, between 2011 and 2015 were included in the study. They were divided into three groups: group 1 – mesothelioma patients; group 2 – other malignancies; and group 3 – benign aetiologies. Group 1 and 2 were termed as the malignant group. Fluid, serum VEGF levels, and the ratio of fluid/serum VEGF level were studied to evaluate the fluid/serum VEGF ratio in all groups.

Results

Twenty cases with mesothelioma, 44 cases with other malignancies, and 20 cases with benign aetiologies were included in this study. No statistically significant difference was found according to serum VEGF levels for all groups, (group 1: 437 ±324 pg/ml, group 2: 354 ±223 pg/ml, group 3: 373 ±217 pg/ml, p = 0.836), while fluid VEGF levels showed a statistically significant difference (group 1: 3359 ±700 pg/ml, group 2: 2175 ±435 pg/ml, group 3: 1092 ±435 pg/ml, p = 0.041). The ratio of fluid to serum VEGF levels showed a difference, at the significance limit, between the malignant (group 1 and group 2) and benign (group 3) groups (8.83 ±1.29 vs. 4.57 ±1.07, p = 0.059) but showed a statistically significant difference between the mesothelioma and benign groups (12.11 ±1.68 vs. 4.57 ±1.07, p = 0.044).

Conclusions

The VEGF fluid/serum ratio may be an applicable parameter in the differential diagnosis of malignant fluids, especially MPM.

The Effect of Aquaporin 1-Inhibition on Vasculogenic Mimicry in Malignant Mesothelioma

Malignant mesothelioma (MM) is an aggressive malignancy of the serosal membranes, with poor overall survival and quality of life. Limited targeted treatment strategies exist due to restricted knowledge of pathogenic pathways. Vasculogenic mimicry (VM) is a newly described phenomenon associated with increased aggressiveness in other malignancies, and has been characterized in MM. Normal mesothelium expresses aquaporin 1 (AQP1) and retained expression has been associated with improved survival in MM. AQP1 is expressed by normal vascular endothelium and is involved in mediating MM cell motility and proliferation. We investigated the role of AQP1 in VM, and its interaction with the pro-angiogenic factor vascular endothelial growth factor A (VEGFA), which is variably expressed in MM. Matrigel VM assays were performed using NCI-H226 and NCI-H28 MM cell lines and primary cells in hypoxia and normoxia. The synthetic blocker AqB050 and siRNA were used to inhibit AQP1, and bevacizumab was used to inhibit VEGF. Inhibition of AQP1 resulted in increased VEGFA secretion by MM cells and reduced VM in MM cell lines in hypoxia but not normoxia. No change in VM was seen in MM primary cells. Combined inhibition of AQP1 and VEGF had no effect on VM in normoxia. In a heterotopic xenograft mouse model, AqB050 treatment did not alter vessel formation. AQP1 may interact with VEGFA and play a role in VM, especially under hypoxic conditions, but the heterogeneity of MM cells may result in different dominant pathways between patients.

Angiogenesis in Schistosoma haematobium-associated urinary bladder cancer

Schistosoma haematobium, a parasitic flatworm that infects more than 100 million people, mostly in the developing world, is the causative agent of urogenital schistosomiasis, and is associated with a high incidence of squamous cell carcinoma (SCC) of the bladder. During infection, eggs are deposited in the bladder causing an intense inflammatory reaction. Angiogenesis is defined as the formation of new blood vessels from preexisting ones and is recognized as a key event in cell proliferation and carcinogenesis and spread of malignant lesions. A growing amount of evidence points to angiogenesis playing a key role in schistosomiasis-associated bladder cancer. Thus, identifying biomarkers of this process plays an important role in the study of cancer. Here, we review recent findings on the role of angiogenesis in bladder cancer and the growth factors that induce and assist in their development, particularly SCC of the bladder associated to urogenital schistosomiasis.

A review of bevacizumab in the treatment of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive cancer with poor prognosis. Systemic chemotherapy is the primary treatment modality for the majority of patients. VEGF plays a key mitogen for MPM cells physiopathology. Bevacizumab, a monoclonal anti-VEGF antibody, was a rational approach to be tested in MPM. Based on the results of the Phase III IFCT-0701 mesothelioma avastin cisplatin pemetrexed study, cisplatin-pemetrexed-bevacizumab is now the accepted standard in France. The National Comprehensive Cancer Network guidelines have also included this combination as an option for standard front-line therapy. This review summarized the efficacy and safety data of bevacizumab in the treatment of patients with MPM.

Regulation of microRNA using promising dietary phytochemicals: Possible preventive and treatment option of malignant mesothelioma

Malignant mesothelioma (MM) is a very aggressive, lethal cancer, and its incidence is increasing worldwide. Development of multi-drug resistance, therapy related side-effects, and disease recurrence after therapy are the major problems for the successful treatment of MM. Emerging evidence indicates that dietary phytochemicals can exert anti-cancer activities by regulating microRNA expression. Until now, only one dietary phytochemical (ursolic acid) has been reported to have MM microRNA regulatory ability. A large number of dietary phytochemicals still remain to be tested. In this paper, we have introduced some dietary phytochemicals (curcumin, epigallocatechin gallate, quercetin, genistein, pterostilbene, resveratrol, capsaicin, ellagic acid, benzyl isothiocyanate, phenethyl isothiocyanate, sulforaphane, indole-3-carbinol, 3,3'-diindolylmethane, diallyl disulphide, betulinic acid, and oleanolic acid) which have shown microRNA regulatory activities in various cancers and could regulate MM microRNAs. In addition to microRNA regulatory activities, curcumin, epigallocatechin gallate, quercetin, genistein, resveratrol, phenethyl isothiocyanate, and sulforaphane have anti-mesothelioma potentials, and pterostilbene, capsaicin, ellagic acid, benzyl isothiocyanate, indole-3-carbinol, 3,3'-diindolylmethane, diallyl disulphide, betulinic acid, and oleanolic acid have potentials to inhibit cancer by regulating the expression of various genes which are also known to be aberrant in MM.

Phase I Trial of Cediranib in Combination with Cisplatin and Pemetrexed in Chemonaive Patients with Unresectable Malignant Pleural Mesothelioma (SWOG S0905)

INTRODUCTION

In malignant pleural mesothelioma, targeting angiogenesis with cediranib, a vascular endothelial growth factor receptor and platelet-derived growth factor receptor inhibitor, may have therapeutic potential.

METHODS

S0905 phase I combined cediranib (two dose cohorts [30 mg and 20 mg daily]) with cisplatin-pemetrexed for six cycles followed by maintenance cediranib in unresectable chemonaive patients with malignant pleural mesothelioma of any histologic subtype. The primary end point established the maximum tolerated dose in combination with cisplatin-pemetrexed in a dose deescalation scheme.

RESULTS

A total of 20 patients were enrolled (seven to the 30-mg cohort and 13 to the 20-mag cohort). In the cediranib 30-mg cohort, two of the initial six patients reported dose-limiting toxicities and the dose was deemed too toxic to continue. In the next cohort, two patients experienced dose-limiting toxicities, and thus, the maximum tolerated dose of cediranib was established as 20 mg. During the six cycles of cisplatin-pemetrexed-cediranib, 20 mg, there were grade 3 toxicities (neutropenia and gastrointestinal) and grade 4 thrombocytopenia. No patients had any significant episodes of bleeding. According to the Response Evaluation Criteria in Solid Tumors (n = 17 evaluable patients), the median progression-free survival was 12.8 months (95% confidence interval [CI]: 6.9-17.2); according to the Modified Response Evaluation Criteria in Solid Tumors (n = 19 evaluable patients), the median progression-free survival was 8.6 months (95% CI: 6.1-10.9). For all patients, the disease control rate at 6 weeks was 90% and median overall survival time was 16.2 months (95% CI: 10.5-28.7).

CONCLUSIONS

Cediranib combined with cisplatin-pemetrexed has a reasonable toxicity profile and preliminary promising efficacy. The phase II S0905 trial will evaluate the efficacy of the triplet regimen compared with the current standard of care, cisplatin-pemetrexed.

A pilot study of zoledronic acid in the treatment of patients with advanced malignant pleural mesothelioma

Purpose

Malignant pleural mesothelioma (MPM) is a rare malignancy with a dismal median survival of <12 months with current therapy. Single and combination chemotherapy regimens have shown only modest clinical benefit. In preclinical studies, nitrogen-containing bisphosphonates (zoledronic acid) inhibit growth of mesothelioma cells by different mechanisms: inhibition of mevalonate pathway, inhibition of angiogenesis, activation of apoptosis through caspase activation, and alteration in activity of matrix metalloproteinases, thereby affecting invasiveness of cancer cells.

Patients and methods

We investigated the role of zoledronic acid in a pilot, single-arm trial of MPM patients with Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0–2 who had progressed on prior treatments or had not received systemic therapy due to poor PS. Primary end point was composite response rate by modified response evaluation criteria in solid tumors and/or metabolic response by 2-deoxy-2-[fluorine-18]fluoro-d-glucose (¹⁸F-FDG) positron emission tomography criteria. Secondary end points were progression-free survival (PFS) and overall survival (OS). Exploratory end points include the effect of zoledronic acid therapy on vascular endothelial growth factor (VEGF), basic fibroblast growth factor, interleukin 8, transforming growth factor beta, mesothelin, and osteopontin levels.

Results

Eight male patients (median age of 62 years) with the following clinical characteristics were treated; ECOG PS was 0–2, 75% with epithelioid type, and 62% had prior chemotherapy Overall composite response rate was 12.5% and the clinical benefit rate (response + stable disease) was 37.5%. Median PFS was 2 months (0.5–21 months) and median OS was 7 months (0.8–28 months). No treatment-related toxicities were observed. Lower VEGF levels were predictive of favorable response and mesothelin levels correlated with disease course.

Conclusion

Zoledronic acid shows modest clinical activity without significant toxicity in patients with advanced MPM.

CD147 overexpression may serve as a promising diagnostic and prognostic marker for gastric cancer: evidence from original research and literature

Gastric cancer (GC) is one of the most common malignancies worldwide. The expression of CD147 protein is associated with GC. However, the clinical role of CD147 in GC has not been investigated extensively. Hence, we focused on studying the association between the expression of CD147 and clinicopathological features of GC patients in this study. Firstly, sixteen publications (1752 cases and 391 controls) and one from our own original research (143 cases) were included in the meta-analysis to obtain a more precise estimation of the diagnostic value of CD147. The results showed that expression rate of CD147 in the GC group is higher than that in control group. Moreover, gender, TNM stage, lymph node metastasis, and depth of invasion are all associated with CD147. Further, sections of gastric tissue from 143 cases underwent immunohistochemical staining for evaluation of CD147 protein expression. Our retrospective analysis demonstrated CD147 protein expression was significantly associated with clinical N stage, and tumor stage. Meanwhile, it can also serve as an independent prognosis biomarker. In conclusion, our results support the role of CD147 as a good indicator of diagnosis and prognosis.

Spotlight on bevacizumab and its potential in the treatment of malignant pleural mesothelioma: the evidence to date

Malignant pleural mesothelioma (MPM) is a rare, but aggressive cancer. Surgery and radiation offer limited benefit, and systemic chemotherapy remains the primary treatment modality for the majority of patients. Vascular endothelial growth factor (VEGF) and its receptor have been recognized as important players in the biology of this disease. Bevacizumab is a monoclonal antibody that binds VEGF and blocks its interaction with the VEGF receptor. Recent studies have shown benefit with the addition of bevacizumab to the combination of cisplatin and pemetrexed in MPM. This combination is now included in the National Comprehensive Cancer Network guidelines (with a category 2A recommendation) as a possible first-line treatment for unresectable MPM in appropriately selected patients. This review discusses the rationale behind the use of bevacizumab in MPM, as well as summarizes the pharmacology, efficacy, safety, and toxicity of bevacizumab across multiple trials. The use of small-molecule inhibitors of angiogenesis in the treatment of MPM is also discussed.

Malignant pleural mesothelioma: an update on investigation, diagnosis and treatment

Malignant pleural mesothelioma is an aggressive malignancy of the pleural surface, predominantly caused by prior asbestos exposure. There is a global epidemic of malignant pleural mesothelioma underway, and incidence rates are predicted to peak in the next few years.This article summarises the epidemiology and pathogenesis of malignant pleural mesothelioma, before describing some key factors in the patient experience and outlining common symptoms. Diagnostic approaches are reviewed, including imaging techniques and the role of various biomarkers. Treatment options are summarised, including the importance of palliative care and methods of controlling pleural effusions. The evidence for chemotherapy, radiotherapy and surgery is reviewed, both in the palliative setting and in the context of trimodality treatment. An algorithm for managing malignant pleural effusion in malignant pleural mesothelioma patients is presented. Finally new treatment developments and novel therapeutic approaches are summarised.

Vasculogenic mimicry in malignant mesothelioma: an experimental and immunohistochemical analysis

Vasculogenic mimicry, the process in which cancer cells form angiomatoid structures independent of or in addition to host angiogenesis has been recorded in several otherwise non-endothelial malignant neoplasms. This study describes evidence of routine vascular mimicry by human mesothelioma cell lines in vitro, when the cell lines are cultured alone or co-cultured with human umbilical vascular endothelial cells, with the formation of angiomatoid tubular networks. Vasculogenic mimicry is also supported by immunohistochemical demonstration of human-specific anti-mitochondria antibody labelling of tumour-associated vasculature of human mesothelioma cells xenotransplanted into nude mice, and by evidence of vascular mimicry in some biopsy samples of human malignant mesotheliomas. These studies show mosaic interlacing of cells that co-label or label individually for immunohistochemical markers of endothelial and mesothelial differentiation. If vascular mimicry in mesothelioma can be characterised more fully, this may facilitate identification of more specific and targeted therapeutic approaches such as anti-angiogenesis in combination with chemotherapy and immunotherapy or other therapeutic approaches.

MDM2 and HIF1alpha expression levels in different histologic subtypes of malignant pleural mesothelioma: correlation with pathological and clinical data

Malignant pleural mesothelioma (MPM) is an aggressive tumor with poor prognosis and limited treatment options. Sarcomatoid/biphasic mesotheliomas are characterized by more aggressive behaviour and a poorer prognosis compared with the epithelioid subtype. To date prognostic and tailored therapeutic biomarkers are lacking. The present study analyzed the expression levels of MDM2 and HIF1alpha in different histologic subtypes from chemonaive MPM patients. Diagnostic biopsies of MPM patients from four Italian cancer centers were centrally collected and analyzed. MDM2 and HIF1alpha expression levels were investigated through immunohistochemistry and RT-qPCR. Pathological assessment of necrosis, inflammation and proliferation index was also performed. Molecular markers, pathological features and clinical characteristics were correlated to overall survival (OS) and progression free survival (PFS). Sixty MPM patients were included in the study (32 epithelioid and 28 non-epithelioid). Higher levels of MDM2 (p < 0.001), HIF1alpha (p = 0.013), necrosis (p = 0.013) and proliferation index (p < 0.001) were seen mainly in sarcomatoid/biphasic subtypes. Higher levels of inflammation were significantly associated with epithelioid subtype (p = 0.044). MDM2 expression levels were correlated with HIF1alpha levels (p = 0.0001), necrosis (p = 0.008) and proliferation index (p = 0.009). Univariate analysis showed a significant correlation of non-epithelioid histology (p = 0.04), high levels of necrosis (p = 0.037) and proliferation index (p = 0.0002) with shorter PFS. Sarcomatoid/biphasic and epithelioid mesotheliomas showed different MDM2 and HIF1alpha expression levels and were characterized by different levels of necrosis, proliferation and inflammation. Further studies are warranted to confirm a prognostic and predictive role of such markers and features.