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Updated: Dec 18, 2025
Experimental Melanoma Immunotherapy Model Using Tumor Vaccination with a Hematopoietic Cytokine
Published on: February 24, 2023
Antibody targeting tumor-derived soluble NKG2D ligand sMIC reprograms NK cell homeostatic survival and function and
Fahmin Basher1,2, Payal Dhar3,4, Xin Wang5
1Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, 29425, USA.
Background:
Melanoma patients who have detectable serum soluble NKG2D ligands either at the baseline or post-treatment of PD1/PDL1 blockade exhibit poor overall survival. Among families of soluble human NKG2D ligands, the soluble human MHC I chain-related molecule (sMIC) was found to be elevated in melanoma patients and mostly associated with poor response to PD1/PDL1 blockade therapy.
Methods:
In this study, we aim to investigate whether co-targeting tumor-released sMIC enhances the therapeutic outcome of PD1/PDL1 blockade therapy for melanoma. We implanted sMIC-expressing B16F10 melanoma tumors into syngeneic host and evaluated therapeutic efficacy of anti-sMIC antibody and anti-PDL1 antibody combination therapy in comparison with monotherapy. We analyzed associated effector mechanism. We also assessed sMIC/MIC prevalence in metastatic human melanoma tumors.
Results:
We found that the combination therapy of the anti-PDL1 antibody with an antibody targeting sMIC significantly improved animal survival as compared to monotherapies and that the effect of combination therapy depends significantly on NK cells. We show that combination therapy significantly increased IL-2Rα (CD25) on NK cells which sensitizes NK cells to low dose IL-2 for survival. We demonstrate that sMIC negatively reprograms gene expression related to NK cell homeostatic survival and proliferation and that antibody clearing sMIC reverses the effect of sMIC and reprograms NK cell for survival. We further show that sMIC/MIC is abundantly present in metastatic human melanoma tumors.
Conclusions:
Our findings provide a pre-clinical proof-of-concept and a new mechanistic understanding to underscore the significance of antibody targeting sMIC to improve therapeutic efficacy of anti-PD1/PDL1 antibody for MIC/sMIC+ metastatic melanoma patients.
Insights
Targeting soluble human MHC I chain-related molecule (sMIC) alongside PD1/PDL1 blockade improves melanoma survival in preclinical models. This combination therapy enhances natural killer (NK) cell function, offering a new strategy for metastatic melanoma patients.
Area of Science:
- Immunology
- Oncology
- Cancer Therapy
Background:
- Soluble NKG2D ligands, particularly soluble human MHC I chain-related molecule (sMIC), are associated with poor survival in melanoma patients undergoing PD1/PDL1 blockade.
- Elevated sMIC levels in melanoma patients correlate with reduced response to PD1/PDL1 blockade therapy.
Purpose of the Study:
- To investigate if co-targeting tumor-released sMIC enhances the therapeutic efficacy of PD1/PDL1 blockade in melanoma.
- To evaluate the underlying effector mechanisms and prevalence of sMIC in metastatic melanoma.
Main Methods:
- Utilized sMIC-expressing B16F10 melanoma tumors in a syngeneic host model.
- Assessed the therapeutic efficacy of combination anti-sMIC and anti-PDL1 antibody therapy versus monotherapies.
- Analyzed immune cell responses, particularly NK cells, and sMIC/MIC expression in human metastatic melanoma tumors.
Main Results:
- Combination therapy significantly improved animal survival compared to monotherapies, with a crucial role for NK cells.
- The combination therapy increased IL-2Rα (CD25) on NK cells, enhancing their sensitivity to IL-2.
- sMIC was found to negatively impact NK cell survival and proliferation, an effect reversed by anti-sMIC antibody treatment. sMIC/MIC was abundant in metastatic melanoma.
Conclusions:
- Co-targeting sMIC with PD1/PDL1 blockade represents a promising strategy to improve therapeutic outcomes for metastatic melanoma.
- This approach offers a new mechanistic understanding for enhancing anti-PD1/PDL1 therapy in MIC/sMIC-positive melanoma patients.
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