Phase II study of first-line bortezomib and cisplatin in malignant pleural mesothelioma and prospective validation of progression free survival rate as a primary end-point for mesothelioma clinical trials (European Organisation for Research and Treatment of Cancer 08052)

Targeting FAcilitates Chromatin Transcription complex inhibits pleural mesothelioma and enhances immunotherapy

BACKGROUND

Diffuse pleural mesothelioma (DPM) is an aggressive therapy-resistant cancer with unique molecular features. Numerous agents have been tested, but clinically effective ones remain elusive. Herein, we propose to use a small molecule CBL0137 (curaxin) that simultaneously suppresses nuclear factor-κB (NF-κB) and activates tumor suppressor p53 via targeting FAcilitates Chromatin Transcription (FACT) complex, a histone chaperone critical for DNA repair.

METHODS

We used DPM cell lines, murine models (xeno- and allo-grafts), plus DPM patient samples to characterize anti-tumor effects of CBL0137 and to delineate specific molecular mechanisms.

RESULTS

We verified that CBL0137 induced cell cycle arrest and apoptosis. We also discovered that DPM is a FACT-dependent cancer with overexpression of both subunits structure-specific recognition protein 1 (SSRP1), a poor prognosis indicator, and suppressor of Ty 16 (SUPT16H). We defined several novel uses of CBL0137 in DPM therapy. In combination with cisplatin, CBL0137 exhibited additive anti-tumor activity compared to monotherapy. Similarly, CBL0137 (systemic) could be combined with other novel agents like microRNA-215 (intrapleural) as a more effective regimen. Importantly, we established that CBL0137 induces immunogenic cell death that contributes to activating immune response pathways in DPM. Therefore, when CBL0137 is combined with dual immune checkpoint inhibitors DPM tumor growth is significantly suppressed.

CONCLUSIONS

We identified an unrecognized molecular vulnerability of DPM based on FACT dependency. CBL0137 alone and in several combinations with different therapeutics showed promising efficacy, including that of improved anti-tumor immunity. Overall, these preclinical findings suggest that CBL0137 could be ideally suited for use in DPM clinical trials.

Antitumoral effects of Bortezomib in malignant mesothelioma: evidence of mild endoplasmic reticulum stress in vitro and activation of T cell response in vivo

BACKGROUND

Malignant mesothelioma (MM) is a rare tumor with a dismal prognosis. The low efficacy of current treatment options highlights the urge to identify more effective therapies aimed at improving MM patients' survival. Bortezomib (Bor) is a specific and reversible inhibitor of the chymotrypsin-like activity of the 20S core of the proteasome, currently approved for the treatment of multiple myeloma and mantle cell lymphoma. On the other hand, Bor appears to have limited clinical effects on solid tumors, because of its low penetration and accumulation into tumor tissues following intravenous administration. These limitations could be overcome in MM through intracavitary delivery, with the advantage of increasing local drug concentration and decreasing systemic toxicity.

METHODS

In this study, we investigated the effects of Bor on cell survival, cell cycle distribution and modulation of apoptotic and pro-survival pathways in human MM cell lines of different histotypes cultured in vitro. Further, using a mouse MM cell line that reproducibly forms ascites when intraperitoneally injected in syngeneic C57BL/6 mice, we investigated the effects of intraperitoneal Bor administration in vivo on both tumor growth and the modulation of the tumor immune microenvironment.

RESULTS

We demonstrate that Bor inhibited MM cell growth and induced apoptosis. Further, Bor activated the Unfolded Protein Response, which however appeared to participate in lowering cells' sensitivity to the drug's cytotoxic effects. Bor also affected the expression of EGFR and ErbB2 and the activation of downstream pro-survival signaling effectors, including ERK1/2 and AKT. In vivo, Bor was able to suppress MM growth and extend mice survival. The Bor-mediated delay of tumor progression was sustained by increased activation of T lymphocytes recruited to the tumor microenvironment.

CONCLUSIONS

The results presented herein support the use of Bor in MM and advocate future studies aimed at defining the therapeutic potential of Bor and Bor-based combination regimens for this treatment-resistant, aggressive tumor.

BAP1 Malignant Pleural Mesothelioma Mutations in Caenorhabditis elegans Reveal Synthetic Lethality between ubh-4/BAP1 and the Proteasome Subunit rpn-9/PSMD13

The deubiquitinase BAP1 (BRCA1-associated protein 1) is associated with BAP1 tumor predisposition syndrome (TPDS). BAP1 is a tumor suppressor gene whose alterations in cancer are commonly caused by gene mutations leading to protein loss of function. By CRISPR-Cas, we have generated mutations in ubh-4, the BAP1 ortholog in Caenorhabditis elegans, to model the functional impact of BAP1 mutations. We have found that a mimicked BAP1 cancer missense mutation (UBH-4 A87D; BAP1 A95D) resembles the phenotypes of ubh-4 deletion mutants. Despite ubh-4 being ubiquitously expressed, the gene is not essential for viability and its deletion causes only mild phenotypes without affecting 20S proteasome levels. Such viability facilitated an RNAi screen for ubh-4 genetic interactors that identified rpn-9, the ortholog of human PSMD13, a gene encoding subunit of the regulatory particle of the 26S proteasome. ubh-4[A87D], similarly to ubh-4 deletion, cause a synthetic genetic interaction with rpn-9 inactivation affecting body size, lifespan, and the development of germ cells. Finally, we show how ubh-4 inactivation sensitizes animals to the chemotherapeutic agent Bortezomib, which is a proteasome inhibitor. Thus, we have established a model to study BAP1 cancer-related mutations in C. elegans, and our data points toward vulnerabilities that should be studied to explore therapeutic opportunities within the complexity of BAP1 tumors.

Establishment and characterization of NCC‑DMM1‑C1, a novel patient‑derived cell line of desmoplastic malignant pleural mesothelioma

Desmoplastic malignant pleural mesothelioma (DMM) is a rare histological variant of malignant pleural mesothelioma, which is a highly aggressive neoplasm of the mesothelium. DMM is associated with distant metastases and short survival. Effective treatments for DMM are not established and the development of histotype-tailored treatments is difficult due to the rarity of the disease. Although patient-derived cancer models are crucial tools for the development of novel therapeutics, they are difficult to obtain for DMM; no DMM cell lines or xenografts are available from public biobanks and only two cell lines have been reported. Thus, the present study aimed to establish a novel cell line of DMM as a resource for drug screening. A cell line of DMM was established, designated as NCC-DMM1-C1, using surgically resected tumor tissues from a 73-year-old male patient with DMM. Characteristics of NCC-DMM1-C1 cells were examined, such as growth, spheroid formation and invasion capability. Drug targets and anti-cancer drugs with anti-proliferative efficacy were examined using a comprehensive kinase activity assay and drug screening of 213 anti-cancer agents, respectively. NCC-DMM1-C1 exhibited fast growth, spheroid formation and invasion capability, suggesting that the NCC-DMM1-C1 cells retained the aggressive features of DMM. NCC-DMM1-C1 cells and the tumor tissue shared common activity profiles of kinases, which included FES, Wee1, platelet-derived growth factor receptor-β and Src. The drug screening revealed that bortezomib, fostamatinib, gemcitabine, homoharringtonine and vinorelbine had anti-proliferative effects, which have not been previously reported for DMM. It was concluded that NCC-DMM1-C1 cells may be a useful tool for the study of DMM.

Preclinical Models and Resources to Facilitate Basic Science Research on Malignant Mesothelioma - A Review

Malignant mesothelioma is an aggressive cancer with poor prognosis, predominantly caused by human occupational exposure to asbestos. The global incidence of mesothelioma is predicted to increase as a consequence of continued exposure to asbestos from a variety of sources, including construction material produced in the past in developed countries, as well as those currently being produced in developing countries. Mesothelioma typically develops after a long latency period and consequently it is often diagnosed in the clinic at an advanced stage, at which point standard care of treatment, such as chemo- and radio-therapy, are largely ineffective. Much of our current understanding of mesothelioma biology, particularly in relation to disease pathogenesis, diagnosis and treatment, can be attributed to decades of preclinical basic science research. Given the postulated rising incidence in mesothelioma cases and the limitations of current diagnostic and treatment options, continued preclinical research into mesothelioma is urgently needed. The ever-evolving landscape of preclinical models and laboratory technology available to researchers have made it possible to study human disease with greater precision and at an accelerated rate. In this review article we provide an overview of the various resources that can be exploited to facilitate an enhanced understanding of mesothelioma biology and their applications to research aimed to improve the diagnosis and treatment of mesothelioma. These resources include cell lines, animal models, mesothelioma-specific biobanks and modern laboratory techniques/technologies. Given that different preclinical models and laboratory technologies have varying limitations and applications, they must be selected carefully with respect to the intended objectives of the experiments. This review therefore aims to provide a comprehensive overview of the various preclinical models and technologies with respect to their advantages and limitations. Finally, we will detail about a highly valuable preclinical laboratory resource to curate high quality mesothelioma biospecimens for research; the biobank. Collectively, these resources are essential to the continued advancement of precision medicine to curtail the increasing health burden caused by malignant mesothelioma.

Ubiquitin-associated protein 2 like (UBAP2L) enhances growth and metastasis of gastric cancer cells

Ubiquitin-proteasome pathway has emerged as therapeutic targets for cancer. GEPIA database analysis showed that the expression of ubiquitin-associated protein 2 like (UBAP2L) in gastric cancer specimens was significantly higher than that in non-tumor tissue, and its high expression is associated with poor survival of gastric cancer patients. This study aims to investigate the role of UBAP2L in gastric cancer. Real-time PCR and western blot results showed that UBAP2L expression was upregulated in gastric cancer cell lines. Loss- and gain-of-function experiments demonstrated that silencing of UBAP2L inhibited proliferation, migration and invasion, and induced apoptosis of gastric cancer cells, and overexpression of UBAP2L played opposite roles. Nude mice inoculated with UBAP2L-silenced gastric cancer cells generated smaller xenografted tumors in vivo. Furthermore, UBAP2L activated Wnt/β-catenin signaling - the accumulation of nuclear β-catenin and the expression of its downstream targets (cyclin D1, AXIN-2 and c-MYC) was facilitated, whereas knockdown of UBAP2L deactivated this signaling. The tumor-suppressing effect of UBAP2L silencing was abolished by forced activation of β-cateninS33A. UBAP2L has been confirmed as a novel and direct target of miR-148b-3p. The anti-tumor effect of miR-148b-3p was partly reversed by UBAP2L overexpression. The expression of miR-148b-3p was negatively correlated with that of UBAP2L in gastric cancer samples. Overall, our study indicates that UBAP2L is required to maintain malignant behavior of gastric cancer cells, which involves the activation of Wnt/β-catenin signaling pathway. We propose UBAP2L as a potential therapeutic target against gastric cancer.

ERS/ESTS/EACTS/ESTRO guidelines for the management of malignant pleural mesothelioma

The European Respiratory Society (ERS)/European Society of Thoracic Surgeons (ESTS)/European Association for Cardio-Thoracic Surgery (EACTS)/European Society for Radiotherapy and Oncology (ESTRO) task force brought together experts to update previous 2009 ERS/ESTS guidelines on management of malignant pleural mesothelioma (MPM), a rare cancer with globally poor outcome, after a systematic review of the 2009-2018 literature. The evidence was appraised using the Grading of Recommendations, Assessment, Development and Evaluation approach. The evidence syntheses were discussed and recommendations formulated by this multidisciplinary group of experts. Diagnosis: pleural biopsies remain the gold standard to confirm the diagnosis, usually obtained by thoracoscopy but occasionally via image-guided percutaneous needle biopsy in cases of pleural symphysis or poor performance status. Pathology: standard staining procedures are insufficient in ∼10% of cases, justifying the use of specific markers, including BAP-1 and CDKN2A (p16) for the separation of atypical mesothelial proliferation from MPM. Staging: in the absence of a uniform, robust and validated staging system, we advise using the most recent 2016 8th TNM (tumour, node, metastasis) classification, with an algorithm for pretherapeutic assessment. Monitoring: patient's performance status, histological subtype and tumour volume are the main prognostic factors of clinical importance in routine MPM management. Other potential parameters should be recorded at baseline and reported in clinical trials. Treatment: (chemo)therapy has limited efficacy in MPM patients and only selected patients are candidates for radical surgery. New promising targeted therapies, immunotherapies and strategies have been reviewed. Because of limited data on the best combination treatment, we emphasize that patients who are considered candidates for a multimodal approach, including radical surgery, should be treated as part of clinical trials in MPM-dedicated centres.

Combination Chemotherapy with Cisplatin and Chloroquine: Effect of Encapsulation in Micelles Formed by Self-Assembling Hybrid Dendritic-Linear-Dendritic Block Copolymers

Clinical outcomes of conventional drug combinations are not ideal due to high toxicity to healthy tissues. Cisplatin (CDDP) is the standard component for many cancer treatments, yet its principal dose-limiting side effect is nephrotoxicity. Thus, CDDP is commonly used in combination with other drugs, such as the autophagy inhibitor chloroquine (CQ), to enhance tumor cell killing efficacy and prevent the development of chemoresistance. In addition, nanocarrier-based drug delivery systems can overcome chemotherapy limitations, decreasing side effects and increasing tumor accumulation. The aim of this study was to evaluate the toxicity of CQ and CDDP against tumor and non-tumor cells when used in a combined treatment. For this purpose, two types of micelles based on Pluronic^® F127 hybrid dendritic–linear–dendritic block copolymers (HDLDBCs) modified with polyester or poly(esteramide) dendrons derived from 2,2′-bis(hydroxymethyl)propionic acid (HDLDBC-bMPA) or 2,2′-bis(glycyloxymethyl)propionic acid (HDLDBC-bGMPA) were explored as delivery nanocarriers. Our results indicated that the combined treatment with HDLDBC-bMPA(CQ) or HDLDBC-bGMPA(CQ) and CDDP increased cytotoxicity in tumor cells compared to the single treatment with CDDP. Encapsulations demonstrated less short-term cytotoxicity individually or when used in combination compared to the free drugs. However, and more importantly, a low degree of cytotoxicity against non-tumor cells was maintained, even when drugs were given simultaneously.

Meta-Analysis of Survival and Development of a Prognostic Nomogram for Malignant Pleural Mesothelioma Treated with Systemic Chemotherapy

(1) Purpose: Malignant pleural mesothelioma (MPM) is a rare cancer with an aggressive course. For patients who are medically inoperable or surgically unresectable, multi-agent systemic chemotherapy remains an accepted standard-of-care. The purpose of this meta-analysis is to provide baseline summative survival estimates as well as evaluate the influence of prognostic variables to provide comparative estimates for future trial designs. (2) Methods: Using PRISMA guidelines, a systematic review and meta-analysis was performed of MPM studies published from 2002-2019 obtained from the Medline database evaluating systemic therapy combinations for locally advanced or metastatic disease. Weighted random effects models were used to calculate survival estimates. The influence of proportions of known prognostic factors on overall survival (OS) were evaluated in the creation of a prognostic nomogram to estimate survival. The performance of this model was evaluated against data generated from one positive phase II study and two positive randomized trials. (3) Results: Twenty-four phase II studies and five phase III trials met the eligibility criteria; 2534 patients were treated on the included clinical studies. Ten trials included a platinum-pemetrexed-based treatment regimen, resulting in a pooled estimate of progression-free survival (PFS) of 6.7 months (95% CI: 6.2-7.2 months) and OS of 14.2 months (95% CI: 12.7-15.9 months). Fifteen experimental chemotherapy regimens have been tested in phase II or III studies, with a pooled median survival estimate of 13.5 months (95% CI: 12.6-14.6 months). Meta-regression analysis was used to estimate OS with platinum-pemetrexed using a variety of features, such as pathology (biphasic vs. epithelioid), disease extent (locally advanced vs. metastatic), ECOG performance status, age, and gender. The nomogram-predicted estimates and corresponding 95% CIs performed well when applied to recent randomized studies. (4) Conclusions: Given the rarity of MPM and the aggressive nature of the disease, innovative clinical trial designs with significantly greater randomization to experimental regimens can be performed using robust survival estimates from prior studies. This study provides baseline comparative values and also allows for accounting for differing proportions of known prognostic variables.

ERS/ESTS/EACTS/ESTRO guidelines for the management of malignant pleural mesothelioma

The European Respiratory Society (ERS)/European Society of Thoracic Surgeons (ESTS)/European Association for Cardio-Thoracic Surgery (EACTS)/European Society for Radiotherapy and Oncology (ESTRO) task force brought together experts to update previous 2009 ERS/ESTS guidelines on management of malignant pleural mesothelioma (MPM), a rare cancer with globally poor outcome, after a systematic review of the 2009-2018 literature. The evidence was appraised using the Grading of Recommendations, Assessment, Development and Evaluation approach. The evidence syntheses were discussed and recommendations formulated by this multidisciplinary group of experts. Diagnosis: pleural biopsies remain the gold standard to confirm the diagnosis, usually obtained by thoracoscopy but occasionally via image-guided percutaneous needle biopsy in cases of pleural symphysis or poor performance status. Pathology: standard staining procedures are insufficient in ∼10% of cases, justifying the use of specific markers, including BAP-1 and CDKN2A (p16) for the separation of atypical mesothelial proliferation from MPM. Staging: in the absence of a uniform, robust and validated staging system, we advise using the most recent 2016 8th TNM (tumour, node, metastasis) classification, with an algorithm for pre-therapeutic assessment. Monitoring: patient's performance status, histological subtype and tumour volume are the main prognostic factors of clinical importance in routine MPM management. Other potential parameters should be recorded at baseline and reported in clinical trials. Treatment: (chemo)therapy has limited efficacy in MPM patients and only selected patients are candidates for radical surgery. New promising targeted therapies, immunotherapies and strategies have been reviewed. Because of limited data on the best combination treatment, we emphasise that patients who are considered candidates for a multimodal approach, including radical surgery, should be treated as part of clinical trials in MPM-dedicated centres.

Impact of acute kidney injury on anticancer treatment dosage and long-term outcomes: a pooled analysis of European Organisation for Research and Treatment of Cancer trials

BACKGROUND

The impact of kidney dysfunction on long-term outcomes of patients with advanced cancer remains unclear.

METHODS

Patients with advanced cancer included in trials conducted by the European Organisation for Research and Treatment of Cancer were eligible for this retrospective analysis. Acute kidney injury (AKI) was identified using serum creatinine levels and using adverse events reported by investigators. The impact of baseline estimated glomerular filtration rates (eGFRs) on progression-free survival (PFS) and overall survival (OS) was investigated. Pooled estimates of the impact of AKI on dose intensity, treatment duration, PFS and OS were obtained following a meta-analytic process.

RESULTS

Nine trials were included in this study, totalling 2872 metastatic patients with various tumour types and various systemic treatment types. Baseline eGFR had homogeneously no impact on PFS or OS. Most Risk, Injury, Failure, Loss of kidney function and End-stage kidney disease (RIFLE) events occurred early during the course of the treatment. AKI was not associated with an increased rate of treatment discontinuation, while it decreased the study treatment dose intensity. Occurrence of a first RIFLE event significantly and homogeneously reduced PFS (pooled hazard ratio = 1.18, 95% confidence interval 1.07-1.30; P = 0.0012), while its impact on OS was more heterogeneous across trials.

CONCLUSION

AKI is associated with reduced treatment dose intensity and reduced PFS. Therefore, close monitoring of the kidney function during the first months of treatment should be included in clinical trial protocols and probably also in daily practice to enable early AKI diagnosis and management. Collaboration between oncologists and nephrologists is needed to reduce the risk of undertreatment of patients experiencing AKI.

Impact of tricyclic antidepressants, selective serotonin reuptake inhibitors, and other antidepressants on overall survival of patients with advanced lung cancer from 2004 to 2014: University of Cincinnati experience

Objectives

To evaluate and categorize the survival benefit of tricyclic antidepressants (TCAs) in lung cancer patients based on systematic computational drug repositioning data.

Methods

Data were retrospectively extracted from the medical records of non-small cell lung cancer (NSCLC) patients from the University of Cincinnati Cancer Medical Center database. Patients receiving antidepressants during their course of anti-cancer treatment were compared with those without antidepressants. Data were analyzed using Kaplan–Meier survival curves with the log-rank test, and overall survival (OS) was calculated from the date of diagnosis until last follow-up or death.

Results

The median OS at 2 and 5 years for patients on antidepressants was 20.3 months (54.7% and 42%) vs 44.3 months (47.6% and 43.2%), which was not significant. The median OS for patients receiving TCAs, selective serotonin reuptake inhibitors, and other antidepressants was 3.17 months, 31.33 months, and 18.50 months, respectively.

Conclusion

We found no significant survival benefit for TCA use in combination with anti-cancer agents in NSCLC patients.

Emerging therapies in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare cancer of the pleural surfaces frequently related to asbestos exposure. It is characterized by a poor prognosis even for patients treated with trimodality therapy, including surgery, chemotherapy and radiotherapy. Moreover, the majority of patients are not candidates for surgery due to disease advanced stage or medical comorbidities. For these patients, the survival rate is even lower and few therapeutic options are currently available. Nevertheless, many interesting novel approaches are under investigation, among which immunotherapy represents one of the most promising emerging strategies. In this review, we will discuss the role of new therapeutic options, particularly immunotherapy, and present the results of the most important and promising clinical trials.

Bortezomib sensitivity is tissue dependent and high expression of the 20S proteasome precludes good response in malignant pleural mesothelioma

Background

Bortezomib is an approved proteasome inhibitor for the treatment of certain lymphoma subtypes. Two clinical trials investigated bortezomib in patients with malignant pleural mesothelioma (MPM) and failed to improve outcome. We present a potential explanation for this event.

Methods

171 patients with MPM were analyzed for their mRNA expression of proteasomal subunits PSMA1, PSMA5, PSMB1, PSMB2, PSMB4 and PSMB5 via qPCR (n=84) or sequencing (n=87 TCGA/cBioPortal data set “Mesothelioma”). Outcome and subunit expression were correlated. Four mesothelial and one fibroblast cell line were treated with bortezomib and cisplatin. Cellular response was measured after 0, 6, 12, 24, 48 and 72 hrs. Enzyme activity of proteasomal subunits was assessed via functional enzyme activity assays.

Results

Patients with MPM presented with elevated expression of proteasomal subunits compared to benign controls (p<0.001). PSMB4 correlated with outcome (Cox propotiortional-hazards model (COXPH): p<0.0175, TCGA/cBioPortal data). In cell lines, apoptosis was the main event with a peak after 48 hr incubation for bortezomib or cisplatin. Only two cell lines with comparably low proteasome activity (PSMB2 and PSMB5) responded to 50 nM and 100 nM bortezomib better than to cisplatin (MRC-5, NCI-H2052). MSTO-211H responded to cisplatin only, whereas the other two cell lines were considered therapy resistant (Met-5A, NCI-H2452).

Interpretation

Two clinical trials testing bortezomib in MPM failed, although MPM presents with high proteasome expression, which predicts bortezomib sensitivity in several tumors. Bortezomib induced apoptosis in MPM cell lines with low proteasome activity only. Bortezomib is not suitable for the treatment of MPM, and biomarker-based stratification could have improved both clinical trials.

Trial registration

NCT00513877 and NCT00458913

What can independent research for mesothelioma achieve to treat this orphan disease?

Introduction: Malignant pleural mesothelioma (MPM) is a rare neoplasm with a poor prognosis, as current therapies are ineffective. Despite the increased understanding of the molecular biology of mesothelioma, there is still a lack of drugs that dramatically enhance patient survival. Area Covered: This review discusses recent and complete clinical trials supported by the NIH, other U.S. Federal agencies, universities and organizations found on clinicaltrials.gov. Firstly, chemotherapy-based trials are described, followed by immunotherapy and multitargeted therapy. Then we introduce drug repositioning and the use of drug docking as tools to find new interesting molecules. Finally, we highlight potential molecular pathways that may play a role in mesothelioma biology and therapy. Expert Opinion: Numerous biases are present in the clinical trials due to a restricted number of cases, inappropriate endpoints and inaccurate stratification of patients which delay the finding of a treatment for MPM. The most crucial issue of independent research for MPM is the lack of more substantive funding to translate these findings to the clinical setting. However, this approach is not necessarily scientific given the low mutational load of mesothelioma relative to other cancers, and therefore patients need a more solid rationale to have a good chance of successful treatment.

New insights into diagnosis and therapeutic options for proliferative hepatoblastoma

Surgery and cisplatin-based treatment of hepatoblastoma (HB) currently guarantee the survival of 70%-80% of patients. However, some important challenges remain in diagnosing high-risk tumors and identifying relevant targetable pathways offering new therapeutic avenues. Previously, two molecular subclasses of HB tumors have been described, C1 and C2, with C2 being the subgroup with the poorest prognosis, a more advanced tumor stage, and the worst overall survival rate. An associated 16-gene signature to discriminate the two tumoral subgroups was proposed, but it has not been transferred into clinical routine. To address these issues, we performed RNA sequencing of 25 tumors and matched normal liver samples from patients. The transcript profiling separated HB into three distinct subgroups named C1, C2A, and C2B, identifiable by a concise four-gene signature: hydroxysteroid 17-beta dehydrogenase 6, integrin alpha 6, topoisomerase 2-alpha, and vimentin, with topoisomerase 2-alpha being characteristic for the proliferative C2A tumors. Differential expression of these genes was confirmed by quantitative RT-PCR on an expanded cohort and by immunohistochemistry. We also revealed significant overexpression of genes involved in the Fanconi anemia (FA) pathway in the C2A subgroup. We then investigated the ability of several described FA inhibitors to block growth of HB cells in vitro and in vivo. We demonstrated that bortezomib, a Food and Drug Administration-approved proteasome inhibitor, strongly impairs the proliferation and survival of HB cell lines in vitro, blocks FA pathway-associated double-strand DNA repair, and significantly impedes HB growth in vivo.

CONCLUSION

The highly proliferating C2A subtype is characterized by topoisomerase 2-alpha gene up-regulation and FA pathway activation, and the HB therapeutic arsenal could include bortezomib for the treatment of patients with the most aggressive tumors. (Hepatology 2018;68:89-102).

Increased sensitivity to apoptosis upon endoplasmic reticulum stress-induced activation of the unfolded protein response in chemotherapy-resistant malignant pleural mesothelioma

BACKGROUND

Standard treatment for advanced malignant pleural mesothelioma (MPM) is a cisplatin/pemetrexed (MTA) regimen; however, this is confronted by drug resistance. Proteotoxic stress in the endoplasmic reticulum (ER) is a hallmark of cancer and some rely on this stress signalling in response to cytotoxic chemotherapeutics. We hypothesise that ER stress and the adaptive unfolded protein response (UPR) play a role in chemotherapy resistance of MPM.

METHODS

In vitro three-dimensional (3D) and ex vivo organotypic culture were used to enrich a chemotherapy-resistant population and recapitulate an in vivo MPM microenvironment, respectively. Markers of ER stress, the UPR and apoptosis were assessed at mRNA and protein levels. Cell viability was determined based on acid phosphatase activity.

RESULTS

MPM cells with de novo and/or acquired chemotherapy resistance displayed low ER stress, which rendered the cells hypersensitive to agents that induce ER stress and alter the UPR. Bortezomib, an FDA-approved proteasome inhibitor, selectively impairs chemotherapy-resistant MPM cells by activating the PERK/eIF2α/ATF4-mediated UPR and augmenting apoptosis.

CONCLUSIONS

We provide the first evidence for ER stress and the adaptive UPR signalling in chemotherapy resistance of MPM, which suggests that perturbation of the UPR by altering ER stress is a novel strategy to treat chemotherapy-refractory MPM.

Survival in Good Performance Malignant Pleural Mesothelioma Patients; Prognostic Factors and Predictors of Response

Purpose: Malignant pleural mesothelioma (MPM) has a poor prognosis in general. Here we sought to evaluate prognostic factors and predictors of response to chemotherapy in good performance (PS=0-I) patients. Methods: We retrospectively reviewed our database and enrolled patients with MPM who received platinum containing chemotherapy (2012-2014). Clinico-pathological and laboratory data were retrieved and Cox and logistic regression multivariate analyses (MVA) were respectively used to identify predictors of survival and response to chemotherapy. Comparison of good vs poor performance status (PS≥II) was accomplished using the Chi (X2) test. Kaplan–Meier survival curves were also obtained and propensity-score matching was performed for survival comparison. Results: Among 114 patients listed during the study period, 82 had good PS=0-I (median age 45years, 43 men, 30 smokers, median weight=77Kg, pretreatment haemoglobin (Hb) level=12g/dL, platelet count=372,000/μL, leukocytes=9,700/μL, neutrophils=6,100/μL, lymphocytes=1,890/μL and neutrophil/lymphocyte ratio (NLR)=3.60 ). Some 65 had asbestosis, 23 had chronic disease, 55 (67.1%) were responders to platinum containing first line chemotherapy. A total of 49 (59.8%) had epithelial MPM. Median-OS and PFS in good PS cases were 17 and 9 months, respectively, as compared to 16 and 8 months for the poor PS group. After matching, better OS was observed among good PS vs poor PS patients (p=0.024) but there was no PFS difference (p=0.176). Significant decrease in PFS was observed among those with advanced nodal N disease (median PFS in N0 and N+ was 10 and 5 months, respectively), non-responders (p=0.012), NLR (p=0.026) and those with an epithelial pathology (p=0.062). MVA demonstrated that advanced (N) status (p=0.015), being a non-responder (p<0.001), NLR (p=0.015) and smoking (p=0.07) adversely affected the prognosis. The only predictor of response was absence of metastasis (M0; p=0.04). Conclusions: In addition to previously recognized factors, like nodal status, response, smoking and NLR, better median survival was evident in our patients with a good PS. Early detection before development of metastasis warrants greater focus to allow better responses to be obtained.

Novel systemic therapy against malignant pleural mesothelioma

Malignant pleural mesothelioma is an aggressive tumor of the pleura with an overall poor prognosis. Even with surgical resection, for which only a subset of patients are eligible, long term disease free survival is rare. Standard first-line systemic treatment consists of a platinum analog, an anti-metabolite, and sometimes anti-angiogenic therapy, but there is currently no well-established standard therapy for refractory or relapsed disease. This review focuses on efforts to develop improved systemic therapy for the treatment of malignant pleural mesothelioma (MPM) including cytotoxic systemic therapy, a variety of tyrosine kinase inhibitors and their downstream effector pathways, pharmacologic targeting of the epigenome, novel approaches to target proteins expressed on mesothelioma cells (such as mesothelin), arginine depletion therapy, and the emerging role of immunotherapy. Overall, these studies demonstrate the challenges of improving systemic therapy for MPM and highlight the need to develop therapeutic strategies to control this disease.

Molecular mechanisms for synergistic effect of proteasome inhibitors with platinum-based therapy in solid tumors

The successful development of the proteasome inhibitor bortezomib as an anticancer drug has improved survival in patients with multiple myeloma. With the emergence of the newly US Food and Drug Administration-approved proteasome inhibitor carfilzomib, ongoing trials are investigating this compound and other proteasome inhibitors either alone or in combination with other chemotherapy drugs. However, in solid tumors, the efficacy of proteasome inhibitors has not lived up to expectations. Results regarding the potential clinical efficacy of bortezomib combined with other agents in the treatment of solid tumors are eagerly awaited. Recent identification of the molecular mechanisms (involving apoptosis and autophagy) by which bortezomib and cisplatin can overcome chemotherapy resistance and sensitize tumor cells to anticancer therapy can provide insights into the development of novel therapeutic strategies for patients with solid malignancies.

Switching off malignant mesothelioma: exploiting the hypoxic microenvironment

Malignant mesotheliomas are aggressive, asbestos-related cancers with poor patient prognosis, typically arising in the mesothelial surfaces of tissues in pleural and peritoneal cavity. The relative unspecific symptoms of mesotheliomas, misdiagnoses, and lack of precise targeted therapies call for a more critical assessment of this disease. In the present review, we categorize commonly identified genomic aberrations of mesotheliomas into their canonical pathways and discuss targeting these pathways in the context of tumor hypoxia, a hallmark of cancer known to render solid tumors more resistant to radiation and most chemo-therapy. We then explore the concept that the intrinsic hypoxic microenvironment of mesotheliomas can be Achilles' heel for targeted, multimodal therapeutic intervention.

The resistance related to targeted therapy in malignant pleural mesothelioma: Why has not the target been hit yet?

Malignant pleural mesothelioma (MPM) is an aggressive tumor of the pleura with a poor prognosis. The most active first-line regimens are platinum compounds and pemetrexed. There is no standard second-line treatment in MPM. Advances in the understanding of tumor molecular biology have led to the development of several targeted treatments, which have been evaluated in clinical trials. Unfortunately none of the explored targeted treatments can currently be recommended as routine treatment in MPM. We reviewed the biological pathways involved in MPM, the clinical trials about targeted therapy, and possible related mechanisms of resistance. We suggest that specific genetic markers are needed as targets of selective therapy. By this way the selection of patients based on the molecular profile may facilitate a therapeutic strategy that allows the use of the most appropriate drug for each patient.

Systemic Approach to Malignant Pleural Mesothelioma: What News of Chemotherapy, Targeted Agents and Immunotherapy?

Malignant pleural mesothelioma is a rare cancer with a cause-effect relationship to asbestos exposure. The prognosis is poor and chemotherapy seems the best treatment option. In the last two decades a deeper understanding of mesothelioma carcinogenesis and invasiveness mechanisms has prompted research efforts to test new agents in patients with malignant pleural mesothelioma, but the results have been modest. Attractive preclinical data disappointed in subsequent experimental phases. Other promising agents failed to improve patient outcomes due to high toxicity. Interesting suggestions have come from preliminary data on immunotherapy. Several trials are ongoing and the results are eagerly awaited. The aim of this review is to discuss the most recent news on systemic therapy for advanced malignant pleural mesothelioma.

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

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

Mesothelioma treatment: Are we on target? A review

Targeted treatment is a therapy directed at a specific molecular target close to a hallmark of cancer. The target should be measurable with a biomarker and measurement of the target should correlate with clinical outcome when targeted treatment is administered. Current clinical guidelines do not recommend targeted or biological therapy in MPM. However, since these recommendations came out, new agents have been investigated in MPM. This review updates the use of targeted and biological treatment in patients with mesothelioma.

Trial Watch: Proteasomal inhibitors for anticancer therapy

The so-called "ubiquitin-proteasome system" (UPS) is a multicomponent molecular apparatus that catalyzes the covalent attachment of several copies of the small protein ubiquitin to other proteins that are generally (but not always) destined to proteasomal degradation. This enzymatic cascade is crucial for the maintenance of intracellular protein homeostasis (both in physiological conditions and in the course of adaptive stress responses), and regulates a wide array of signaling pathways. In line with this notion, defects in the UPS have been associated with aging as well as with several pathological conditions including cardiac, neurodegenerative, and neoplastic disorders. As transformed cells often experience a constant state of stress (as a result of the hyperactivation of oncogenic signaling pathways and/or adverse microenvironmental conditions), their survival and proliferation are highly dependent on the integrity of the UPS. This rationale has driven an intense wave of preclinical and clinical investigation culminating in 2003 with the approval of the proteasomal inhibitor bortezomib by the US Food and Drug Administration for use in multiple myeloma patients. Another proteasomal inhibitor, carfilzomib, is now licensed by international regulatory agencies for use in multiple myeloma patients, and the approved indications for bortezomib have been extended to mantle cell lymphoma. This said, the clinical activity of bortezomib and carfilzomib is often limited by off-target effects, innate/acquired resistance, and the absence of validated predictive biomarkers. Moreover, the antineoplastic activity of proteasome inhibitors against solid tumors is poor. In this Trial Watch we discuss the contribution of the UPS to oncogenesis and tumor progression and summarize the design and/or results of recent clinical studies evaluating the therapeutic profile of proteasome inhibitors in cancer patients.

Systemic treatment of malignant pleural mesothelioma: new agents in clinical trials raise hope of relevant improvements

PURPOSE OF REVIEW

Malignant pleural mesothelioma (MPM) is a rare malignancy with limited therapeutic options and its incidence is still increasing in both Europe and the developing nations. Prognosis of MPM patients is poor even if the median survival durations have been slightly improved after the introduction of the up-to-date chemotherapy combination with pemetrexed and cisplatin. There is a continuing unmet need to develop better systemic treatment for this disease, but the rarity of the tumor type creates formidable challenges in clinical trial research.

RECENT FINDINGS

Better understanding of the molecular machinery of MPM leads to the design and synthesis of novel compounds targeted against pathways identified as crucial for MPM cell proliferation and metastasis. Most efforts aim at improving standard first-line therapy, or developing effective second-line treatments. Several classes of drugs are currently being explored either in combination with cisplatin and pemetrexed or as single agent for relapsed or progressive MPM.

SUMMARY

This review focuses on several ongoing or recently completed clinical trials investigating novel, promising agents as first-line or second-line therapy for advanced MPM.

Malignant mesothelioma: development to therapy

Malignant mesothelioma (MM) is an aggressive cancer of the mesothelium caused by asbestos. Asbestos use has been reduced but not completely stopped. In addition, natural or man-made disasters will continue to dislodge asbestos from old buildings into the atmosphere and as long as respirable asbestos is available, MM will continue to be a threat. Due to the long latency period of MM development, it would still take decades to eradicate this disease if asbestos was completely removed from our lives today. Therefore, there is a need for researchers and clinicians to work together to understand this deadly disease and find a solution for early diagnosis and treatment. This article focuses on developmental mechanisms as well as current therapies available for MM.

Knockdown of ubiquitin associated protein 2-like inhibits the growth and migration of prostate cancer cells

The ubiquitin-proteasome system (UPS) is involved in the development of cancer in various functions. Inhibition of the ubiquitin-proteasome has been revealed to be a powerful therapeutic method for carcinoma. Ubiquitin associated protein 2-like (UBAP2L) is believed to be involved in the ubiquitin‑proteasome pathway; however, the role of UBAP2L in human prostate cancer is still unknown. In the present study, we found that UBAP2L was expressed in a number of prostate carcinoma cell lines. Using lentiviral-mediated RNA interference (RNAi), we efficiently knocked down endogenous UBAP2L expression at the mRNA and protein levels. After UBAP2L disruption, the proliferation and colony formation ability were significantly reduced in the PC-3 and DU145 cells. Flow cytometric analysis showed that UBAP2L knockdown blocked cell cycle progression. Downregulation of UBAP2L inhibited the migration of PC-3 and DU145 cells, as determined by Transwell assay. Moreover, depletion of UBAP2L blocked the AMPKα, Bad and PRAS40 signaling pathways. In conclusion, our results suggest that UBAP2L may play a role in prostate cancer growth and metastasis, and knockdown of UBAP2L by RNAi may serve as a potential therapeutic approach for prostate cancer.

Malignant pleural mesothelioma: current and future perspectives

Mesothelioma still remains an occupational related cancer with severe outcome. It is usually diagnosed at advanced stage since it does not demonstrate early symptoms. Several efforts have been made towards removing all materials inducing mesothelioma in the work setting and new work protection measures have been applied. Although we have new targeted treatments and radical surgery as arrows in the quiver, the type of mesothelioma and early diagnosis still remain the best treatment approach. Novel treatment modalities have been explored and several others are already on the way. In the current review we will present current data for mesothelioma and future perspectives.