scholarly journals 20. MELANOMA CELL INTRINSIC GABAA RECEPTOR ENHANCEMENT POTENTIATES RADIATION AND IMMUNE CHECKPOINT INHIBITOR RESPONSE BY PROMOTING DIRECT AND T CELL-MEDIATED ANTI-TUMOR ACTIVITY

2020 ◽  
Vol 2 (Supplement_2) ◽  
pp. ii3-ii3
Author(s):  
Soma Sengupta ◽  
Tahseen Nasti ◽  
Milota Kaluzova ◽  
Laura Kallay ◽  
Johannes Melms ◽  
...  

Abstract Most metastatic melanoma patients exhibit poor and variable response to radiotherapy and targeted therapies, including immune checkpoint inhibitors. There is a need for therapeutics that can potentiate existing treatments to positively impact clinical outcomes of metastatic melanoma patients. We reanalyzed melanoma TCGA transcriptomes and identified, as linked to previously defined molecular subgroups, enhanced expression of genes coding for subunits of the Type A GABA receptor (GABAAR), a chloride ion channel and major inhibitory neurotransmitter receptor. Using whole-cell patch clamp electrophysiology, we find that melanoma cells possess GABAARs that control membrane permeability to anions. Select benzodiazepines, by enhancing GABAAR mediated anion transport, depolarize melanoma cell mitochondrial membrane potential and impair cell viability in vitro. Using a syngeneic melanoma mouse model, we find that a benzodiazepine promotes reduction in tumor volume when administered alone and potentiated radiation or immune checkpoint inhibitor α-PD-L1. When a benzodiazepine is combined with concurrent α-PD-L1 and a sub-lethal radiation dose, there is near complete loss of tumor, beyond what is observed for benzodiazepine with radiation or α-PD-L1. Mechanistically, benzodiazepine with radiation or α-PD-L1 results in ipsilateral and an abscopal tumor volume reduction commensurate with enhanced infiltration into the tumor milieu of polyfunctional CD8 T-cells. There is also an increased expression of genes with roles in the cytokine-cytokine receptor and p53 signaling pathways. This study provides evidence for melanoma cell GABAARs as a therapeutic vulnerability with benzodiazepines promoting both direct and immune-mediated anti-tumor activity.

2021 ◽  
Vol 14 (1) ◽  
pp. e238235
Author(s):  
Kwang Kiat Sim ◽  
Katie Connell ◽  
Mayank Bhandari ◽  
David Paton

Peritoneal melanosis is an uncommon benign condition, the pathophysiology of which is unclear. Macroscopically, it appears as diffuse dark brown or black pigmentation within the peritoneum, mimicking more sinister conditions such as metastatic melanoma. It has been described in a variety of contexts, but only exceedingly rarely in association with metastatic melanoma, with only two previous published case reports. We present a case of peritoneal melanosis associated with metastatic melanoma involving the spleen, previously treated with targeted and immune checkpoint inhibitor therapy. With increasing reports of melanoma regression manifesting as cutaneous tumorous melanosis in patients treated with immune checkpoint inhibitors, we postulate that, similarly, immunotherapy and tumour regression might have a role to play in the pathogenesis of the peritoneal pigmentation in this case.


2020 ◽  
Vol 7 (3) ◽  
pp. 1
Author(s):  
Nivedita Sudhekar ◽  
Binoy Yohannan ◽  
Mark Feldman

Background: Immune checkpoint inhibitors have changed the therapeutic milieu for patients with metastatic melanoma. However, their use may promote autoimmunity in virtually any organ in the body due to the blockade of intrinsic immune down regulators such as cytotoxic T-lymphocyte antigen- 4 (CTLA-4), programmed cell death 1 (PD1) or its ligand (PDL1). Immune mediated adverse neurological events are rare with these agents, however, and are seen in < 1% of treated patients. We report a patient with immune checkpoint inhibitor associated autoimmune encephalitis, with complete clinical recovery after treatment.Case Report: A 49-year-old female with metastatic melanoma currently on nivolumab therapy but recently on ipilimumab/nivolumab combined therapy presented with a new headache. She also reported associated confusion, loss of balance, personality changes and language difficulty. Magnetic resonance imaging of the brain did not reveal any evidence of metastasis, infarct, meningitis, or encephalitis. Lumbar puncture revealed an elevated protein level and pleocytosis, with a normal glucose level. She was started on empiric glucocorticoid therapy with a presumptive diagnosis of immune checkpoint inhibitor associated autoimmune encephalitis. She improved considerably by day 3 of treatment with complete resolution of neurological symptoms by day 5.Conclusion: Immune checkpoint inhibitors are increasingly important in cancer immunotherapy as they can cause sustained remissions in patients with metastatic melanoma and other malignancies. Because these drugs block immune-regulatory targets, they can lead to enhanced activation of immune system resulting in immune-related adverse events. Autoimmune encephalitis is a rare immune-related adverse event associated with immune checkpoint inhibitors. The incidence of autoimmune encephalitis is higher with combination or sequential CTLA-4 (ipilimumab) and PD1(nivolumab) inhibitor therapy than with monotherapy. With more widespread use of immunotherapy, it is important for clinicians to be aware of this rare and reversible cause of encephalitis. Early recognition and prompt initiation of immunosuppressive therapy with glucocorticoids is essential to enhance neurological recovery.


2019 ◽  
Vol 26 (1) ◽  
pp. 224-227 ◽  
Author(s):  
Eric D Johnson ◽  
Katie Kerrigan ◽  
Katerina Butler ◽  
Shiven B Patel

Purpose Nivolumab is a fully human IgG4 programmed death 1 immune checkpoint inhibitor (ICI) antibody that has anti-tumor activity by selectively blocking the interaction of the programmed death 1 receptor with its two known programmed death ligands PD-L1 and PD-L2. In doing so, this immune checkpoint inhibitor removes the negative signal stifling T cell activation and proliferation within the tumor microenvironment and demonstrates favorable antitumor activity. Case report We report an interesting case of immune checkpoint inhibitor-induced primary hypothyroidism with associated hypothyroid myopathy in a young patient with surgically resected stage IIIB melanoma receiving adjuvant nivolumab. He presented 12 weeks into therapy with severe myalgias, arthralgias, and intermittent disequilibrium of unclear etiology. Laboratory evaluation demonstrated a significant elevation in thyroid stimulating hormone and creatine kinase with an undetectable free T4 with standard laboratory measurement. With thyroid hormone replacement therapy alone, he had rapid improvement in his musculoskeletal symptoms and laboratory parameters over a three-week period. Discussion This case emphasizes the serious nature of endocrine immune-related adverse events in patients receiving immune checkpoint inhibitors. Additionally, it highlights that unlike most other immune-related adverse events, endocrine immune-related adverse events can generally be managed with adequate hormone replacement alone with swift improvements in symptoms. This allows patients to continue immune checkpoint inhibitors safely without immunosuppression which may dampen the anti-tumor activity of these agents. Conclusion This case highlights the importance of early recognition and the appropriate management of endocrine immune-related adverse events to maximize patient safety and good outcomes.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cecile Geuijen ◽  
Paul Tacken ◽  
Liang-Chuan Wang ◽  
Rinse Klooster ◽  
Pieter Fokko van Loo ◽  
...  

AbstractImmune checkpoint inhibitors demonstrate clinical activity in many tumor types, however, only a fraction of patients benefit. Combining CD137 agonists with these inhibitors increases anti-tumor activity preclinically, but attempts to translate these observations to the clinic have been hampered by systemic toxicity. Here we describe a human CD137xPD-L1 bispecific antibody, MCLA-145, identified through functional screening of agonist- and immune checkpoint inhibitor arm combinations. MCLA-145 potently activates T cells at sub-nanomolar concentrations, even under suppressive conditions, and enhances T cell priming, differentiation and memory recall responses. In vivo, MCLA-145 anti-tumor activity is superior to immune checkpoint inhibitor comparators and linked to recruitment and intra-tumor expansion of CD8 + T cells. No graft-versus-host-disease is observed in contrast to other antibodies inhibiting the PD-1 and PD-L1 pathway. Non-human primates treated with 100 mg/kg/week of MCLA-145 show no adverse effects. The conditional activation of CD137 signaling by MCLA-145, triggered by neighboring cells expressing >5000 copies of PD-L1, may provide both safety and potency advantages.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A711-A711
Author(s):  
Matthew Robinson ◽  
Kevin Vervier ◽  
Simon Harris ◽  
David Adams ◽  
Doreen Milne ◽  
...  

BackgroundThe gut microbiome of cancer patients appears to be associated with response to Immune Checkpoint Inhibitor (ICIs) treatment.1–4 However, the bacteria linked to response differ between published studies.MethodsLongitudinal stool samples were collected from 69 patients with advanced melanoma receiving approved ICIs in the Cambridge (UK) MELRESIST study. Pretreatment samples were analysed by Microbiotica, using shotgun metagenomic sequencing. Microbiotica’s sequencing platform comprises the world’s leading Reference Genome Database and advanced Microbiome Bioinformatics to give the most comprehensive and precise mapping of the gut microbiome. This has enabled us to identify gut bacteria associated with ICI response missed using public reference genomes. Published microbiome studies in advanced melanoma,1–3renal cell carcinoma (RCC) and non-small cell lung cancer (NSCLC)4 were reanalysed with the same platform.ResultsAnalysis of the MELRESIST samples showed an overall change in the microbiome composition between advanced melanoma patients and a panel of healthy donor samples, but not between patients who subsequently responded or did not respond to ICIs. However, we did identify a discrete microbiome signature which correlated with response. This signature predicted response with an accuracy of 93% in the MELRESIST cohort, but was less predictive in the published melanoma cohorts.1–3 Therefore, we developed a bioinformatic analytical model, incorporating an interactive random forest model and the MELRESIST dataset, to identify a microbiome signature which was consistent across all published melanoma studies. This model was validated three times by accurately predicting the outcome of an independent cohort. A final microbiome signature was defined using the validated model on MELRESIST and the three published melanoma cohorts. This was very accurate at predicting response in all four studies combined (91%), or individually (82–100%). This signature was also predictive of response in a NSCLC study and to a lesser extent in RCC. The core of this signature is nine bacteria significantly increased in abundance in responders.ConclusionsAnalysis of the MELRESIST study samples, precision microbiome profiling by the Microbiotica Platform and a validated bioinformatic analysis, have enabled us to identify a unique microbiome signature predictive of response to ICI therapy in four independent melanoma studies. This removes the challenge to the field of different bacteria apparently being associated with response in different studies, and could represent a new microbiome biomarker with clinical application. Nine core bacteria may be driving response and hold potential for co-therapy with ICIs.Ethics ApprovalThe study was approved by Newcastle & North Tyneside 2 Research Ethics Committee, approval number 11/NE/0312.ReferencesMatson V, Fessler J, Bao R, et al. The commensal microbiome is associated with anti-PD-1 efficacy in metastatic melanoma patients. Science 2018;359(6371):104–108.Gopalakrishnan V, Spencer CN, Nezi L, et al. Gut microbiome modulates response to anti-PD-1 immunotherapy in melanoma patients. Science 2018;359(6371):97–103.Frankel AE, Coughlin LA, Kim J, et al. Metagenomic shotgun sequencing and unbiased metabolomic profiling identify specific human gut microbiota and metabolites associated with immune checkpoint therapy efficacy in melanoma patients. Neoplasia 2017;19(10):848–855.Routy B, Le Chatelier E, Derosa L, et al. Gut microbiome influences efficacy of PD-1-based immunotherapy against epithelial tumors. Science 2018;359(6371):91–97.


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