Mesothelial cells and pleural immunology

Mesothelial cells are specialized cells that cover the pleural surface as well as other serosal surfaces of most internal organs. Mesothelial cells can have dierent phenotypes which are likely to reect dierences in the functions of parietal and visceral pleura, as well as their activational state, particularly following injury. Mesothelial cells synthesize and secrete glycosaminoglycans and surfactant1 to provide lubrication between parietal and visceral pleura and play critical roles in the maintenance of pleural homeostasis in response to stimuli: mechanical injury, inammation, and immunoregulation. e main pleural pathologies are infections (tuberculosis [TB], other bacterial, and viral infections), brosis (adhesions, loculations, and pleural plaques), and cancers (e.g., mesothelioma). is chapter summarizes our present knowledge on the biology of mesothelial cells, focusing on immune regulation in the pleura and highlighting key cytokines that drive inammatory and immune responses

Living with mesothelioma: A systematic review of patient and caregiver psychosocial support needs

Objective: Practice guidelines emphasize the importance of investigating psychosocial distress in mesothelioma patients and family caregivers. We aimed to synthesize research on the psychosocial support needs of mesothelioma patients and their family caregivers. Methods: We conducted a systematic review with a narrative synthesis and quality assessment. The review process adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results: MEDLINE, EMBASE, Scopus, PsychArticles, and PsycINFO were searched until December 2020 and 37 studies in English met inclusion criteria. Most (n = 24) included mesothelioma patients as a very small proportion of their cancer samples. A narrative synthesis was conducted on the 13 studies including only mesothelioma patients (n = 297) and/or caregivers (n = 82). Patients and caregivers want improvements in the diagnosis delivery and access to palliative care. Patients want emotional support, patient-centered treatment, improved information about illness progression and death, and to meet others with mesothelioma. Caregivers want one-on-one practical and emotional support. Study quality varied. Conclusions: Few studies focus on the psychosocial support needs relevant to mesothelioma. Mesothelioma patients and family caregivers highlight targeted psychosocial care as an unmet need. Practice Implications: Efforts are required to design and test psychosocial interventions for this vulnerable and overlooked group. Protocol Registration: PROSPERO (registration number CRD42020167852)

Identification of a CD8+ T-cell response to a predicted neoantigen in malignant mesothelioma

Neoantigens present unique and specific targets for personalized cancer immunotherapy strategies. Given the low mutational burden yet immunotherapy responsiveness of malignant mesothelioma (MM) when compared to other carcinogen-induced malignancies, identifying candidate neoantigens and T cells that recognize them has been a challenge. We used pleural effusions to gain access to MM tumor cells as well as immune cells in order to characterize the tumor-immune interface in MM. We characterized the landscape of potential neoantigens from SNVs identified in 27 MM patients and performed whole transcriptome sequencing of cell populations from 18 patient-matched pleural effusions. IFNγ ELISpot was performed to detect a CD8+ T cell responses to predicted neoantigens in one patient. We detected a median of 68 (range 7–258) predicted neoantigens across the samples. Wild-type non-binding to mutant binding predicted neoantigens increased risk of death in a model adjusting for age, sex, smoking status, histology and treatment (HR: 33.22, CI: 2.55–433.02, p = .007). Gene expression analysis indicated a dynamic immune environment within the pleural effusions. TCR clonotypes increased with predicted neoantigen burden. A strong activated CD8+ T-cell response was identified for a predicted neoantigen produced by a spontaneous mutation in the ROBO3 gene. Despite the challenges associated with the identification of bonafide neoantigens, there is growing evidence that these molecular changes can provide an actionable target for personalized therapeutics in difficult to treat cancers. Our findings support the existence of candidate neoantigens in MM despite the low mutation burden of the tumor, and may present improved treatment opportunities for patients

MicroRNA signatures in malignant pleural mesothelioma effusions

Malignant pleural mesothelioma (MPM) is an incurable cancer of the pleura that can be difficult to diagnose. Biomarkers for an easier and/or earlier diagnosis are needed. Approximately 90% of MPM patients develop a pleural effusion (PE). PEs are ideal sources of biomarkers as the fluid would almost always require drainage for diagnostic and/or therapeutic reasons. However, differentiating MPM PE from PE caused by other diseases can be challenging. MicroRNAs are popular biomarkers given their stable expression in tissue and fluid. MicroRNAs have been analysed in PE cytology samples for the diagnosis of MPM but have not been measured in frozen/fresh PE. We hypothesise that microRNAs expressed in PE are biomarkers for MPM. TaqMan OpenArray was used to analyse over 700 microRNAs in PE cells and supernatants from 26 MPMs and 21 other PE-causing diseases. In PE cells, combining miR-143, miR-210, and miR-200c could differentiate MPM with an area under the curve (AUC) of 0.92. The three-microRNA signature could also discriminate MPM from a further 40 adenocarcinomas with an AUC of 0.9887. These results suggest that the expression of miR-143, miR-210, and miR-200c in PE cells might provide a signature for diagnosing MPM

The Novel Protein Suppressed in Lung Cancer Down-Regulated in Lung Cancer Tissues Retards Cell Proliferation and Inhibits the Oncokinase Aurora-A

Introduction: In an attempt to search for genes with abnormal expression in cancers, Suppressed in Lung Cancer (SLAN, also known as KIAA0256) is found underexpressed in human lung cancer tissues by quantitative real-time PCR (Q-RT-PCR). The study set out to characterize SLAN protein and explore its cellular functions. Methods: SLAN or its specific short hairpin RNA, full length or various deletion mutants were overexpressed in 293T or lung cancer cell lines, and cell proliferation, cell cycle, mitosis progression, and spindle configuration were surveyed. Results: SLAN and its deletion mutants are localized to many subcellular locations such as endoplasmic reticulum (ER), nucleus, nucleolus, spindle pole and midbody, suggesting SLAN may function as a multifunctional protein. Overexpression of SLAN per se or its short hairpin RNAs (shRNAs) inhibits or accelerates cell proliferation through prolonging or shortening mitosis. Time-lapse microscopic recording reveals that cells overexpressing exogenous SLAN are arrested in mitosis or cannot undergo cytokinesis. SLAN 2-551 mutants drastically arrest cells in mitosis, where alpha- and gamma-tubulin are disorganized. SLAN employs C-terminal to interact with Aurora-A, a key mitosis regulator and an oncogenic kinase associated with a wide range of human cancers. SLAN negatively regulates the activity of Aurora-A by directly inhibiting kinase activity in vitro or reducing the level of active Aurora-A in cells. SLAN is frequently reduced in lung cancer tissues overexpressing Aurora-A, arguing for the necessity to suppress SLAN during the Aurora-A-associated cancer formation. Conclusions: Taken together, we have identified a novel protein SLAN downregulated in lung caner, having multiple subcellular localization including spindle matrix and midbody, inhibiting cell proliferation and Aurora-A

PPARα and PPARγ activation is associated with pleural mesothelioma invasion but therapeutic inhibition is ineffective

Mesothelioma is a cancer that typically originates in the pleura of the lungs. It rapidly invades the surrounding tissues, causing pain and shortness of breath. We compared cell lines injected either subcutaneously or intrapleurally and found that only the latter resulted in invasive and rapid growth. Pleural tumours displayed a transcriptional signature consistent with increased activity of nuclear receptors PPARα and PPARγ and with an increased abundance of endogenous PPAR-activating ligands. We found that chemical probe GW6471 is a potent dual PPARα/γ antagonist with anti-invasive and anti-proliferative activity in vitro. However, administration of GW6471 at doses that provided sustained plasma exposure levels sufficient for inhibition of PPARα/γ transcriptional activity did not result in significant anti-mesothelioma activity in mice. Lastly, we demonstrate that the in vitro antitumour effect of GW6471 is off-target. We conclude that dual PPARα/γ antagonism alone is not a viable treatment modality for mesothelioma