Dataset Information

TGFβ2 Induces the Soluble Isoform of CTLA-4 - Implications for CTLA-4 Based Checkpoint Inhibitor Antibodies in Malignant Melanoma.

ABSTRACT: Malignant melanoma is an aggressive form of cancer, which can be treated with anti-CTLA-4 and anti-PD-1 checkpoint inhibitor antibodies but while anti-CTLA-4 antibodies have clear benefits for some patients with melanoma, productive responses are difficult to predict and often associated with serious immune related adverse events. Antibodies specific to CTLA-4 bind two major isoforms of CTLA-4 in humans, the receptor isoform and a second naturally secretable, soluble isoform - sCTLA-4. The primary aim here was to examine the effect of selectively blocking the function of sCTLA-4 on in vitro immune responses from volunteer healthy or melanoma patient PBMC samples. Addition of recombinant sCTLA-4 to healthy PBMC samples demonstrated sCTLA-4 to have immunosuppressive capacity comparable to recombinant CTLA4-Ig, partially reversible upon antibody blockade. Further, we identified a mechanistic relationship where melanoma patient TGFβ2 serum levels correlated with sCTLA-4 levels and provided the basis for a novel protocol to enhance sCTLA-4 production and secretion by T cells with TGFβ2. Finally, a comparison of selective antibody blockade of sCTLA-4 demonstrated that both healthy and melanoma patient effector cytokine responses can be significantly increased. Overall, the data support the notion that sCTLA-4 is a contributory factor in cancer immune evasion.

SUBMITTER: Khanolkar RC

PROVIDER: S-EPMC8767111 | biostudies-literature | 2021

REPOSITORIES: biostudies-literature

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TGFβ2 Induces the Soluble Isoform of CTLA-4 - Implications for CTLA-4 Based Checkpoint Inhibitor Antibodies in Malignant Melanoma.

Khanolkar Rahul C RC Zhang Chu C Al-Fatyan Farah F Lawson Linda L Depasquale Ivan I Meredith Fiona M FM Muller Frank F Nicolson Marianne M Dahal Lekh Nath LN Abu-Eid Rasha R Rajpara Sanjay S Barker Robert Norman RN Ormerod Anthony D AD Ward Frank James FJ

Frontiers in immunology 20220105

Malignant melanoma is an aggressive form of cancer, which can be treated with anti-CTLA-4 and anti-PD-1 checkpoint inhibitor antibodies but while anti-CTLA-4 antibodies have clear benefits for some patients with melanoma, productive responses are difficult to predict and often associated with serious immune related adverse events. Antibodies specific to CTLA-4 bind two major isoforms of CTLA-4 in humans, the receptor isoform and a second naturally secretable, soluble isoform - sCTLA-4. The prima ...[more]

PMID: 35069536

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Project description:BackgroundMetformin is one of the biguanides commonly used in patients with type II Diabetes Mellitus. Apart from its hypoglycemic properties, metformin also inhibits the cell cycle by restricting protein synthesis and cell proliferation via regulating the LKB1/AMPL pathway. Furthermore, it also enhances the PD-1 blockade through a reduction of tumor hypoxia. Metformin has shown a significant favorable impact on treatment-related outcomes in solid tumors, but these outcomes have not been replicated in the limited clinical studies done on malignant melanoma. Moreover, none of these studies have reported on the efficacy of the combined use of metformin and immune checkpoint inhibitors (ICIs).MethodsThis is a retrospective cohort study that includes patients diagnosed with metastatic malignant melanoma and treated with ipilimumab, nivolumab, and/or pembrolizumab (Cohort A); or ipilimumab, nivolumab, and/or pembrolizumab plus metformin (Cohort B) between January 1st 2011 through December 15th 2017. In this study, patients are stratified based on anti-PD-1 only and anti-CTLA4/anti-PD-1 combination therapies in each cohort. Objective response rate (ORR) is the primary endpoint. Disease control rate (DCR), overall survival (OS) and progression-free survival (PFS) are the secondary endpoints.ResultsCohort A had 33 patients (60%), while cohort B had 22 (40%). Overall patient characteristics were similar between both cohorts. ORR was higher in cohort B (68.2% vs. 54.5%, P = 0.31). The DCR was higher in cohort B as well (77.3% vs. 60.6%, P = 0.19). Median OS (46.7 months vs. 28 months), and median PFS (19.8 months vs. 5 months) were longer in cohort B. However, on univariate and multivariate analyses, none of these differences were statistically significant. The mean number of new metastatic sites which appeared during therapy were significantly higher in cohort A (A:1.51 vs. B:0.59, P = 0.009).ConclusionWe have observed favorable treatment-related outcomes (ORR, DCR, median PFS and median OS) in patients who have received metformin in combination with ICIs without reaching significance, probably, due to small sample size. Hence, large prospective clinical trials are required to study the synergistic effect of metformin in combination with ICIs before it can be recommended as routine additive therapy.

Dataset Information

TGFβ2 Induces the Soluble Isoform of CTLA-4 - Implications for CTLA-4 Based Checkpoint Inhibitor Antibodies in Malignant Melanoma.

Publications

TGFβ2 Induces the Soluble Isoform of CTLA-4 - Implications for CTLA-4 Based Checkpoint Inhibitor Antibodies in Malignant Melanoma.

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