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Updated: Oct 4, 2025
Experimental Melanoma Immunotherapy Model Using Tumor Vaccination with a Hematopoietic Cytokine
Published on: February 24, 2023
Immune priming using DC- and T cell-targeting gene therapy sensitizes both treated and distant B16 tumors to
Jessica Wenthe1, Sedigheh Naseri1, Ann-Charlotte Hellström1
1Uppsala University, Department of Immunology, Genetics and Pathology, Science for Life Laboratory, 751 85 Uppsala, Sweden.
Abstract:
Immune checkpoint inhibitors have revolutionized the treatment of metastatic melanoma, but most tumors show resistance. Resistance is connected to a non-T cell inflamed phenotype partially caused by a lack of functional dendritic cells (DCs) that are crucial for T cell priming. Herein, we investigated whether the adenoviral gene vehicle mLOAd703 carrying both DC- and T cell-activating genes can lead to inflammation in a B16-CD46 model and thereby overcome resistance to checkpoint inhibition therapy. B16-CD46 cells were injected subcutaneously in one or both flanks of immunocompetent C57BL/6J mice. mLOAd703 treatments were given intratumorally alone or in combination with intraperitoneal checkpoint inhibition therapy (anti-PD-1, anti-PD-L1, or anti-TIM-3). Tumor, lymph node, spleen, and serum samples were analyzed for the presence of immune cells and cytokines/chemokines. B16-CD46 tumors were non-inflamed and resistant to checkpoint blockade. In contrast, mLOAd703 treatment led to infiltration of the tumor by CD8+ T cells, natural killer (NK) cells, and CD103+ DCs, accompanied by a systemic increase of pro-inflammatory cytokines interferon γ (IFN-γ), tumor necrosis factor alpha (TNF-α), and interleukin-27 (IL-27). This response was even more pronounced after combining the virus with checkpoint therapy, in particular with anti-PD-L1 and anti-TIM-3, leading to further reduced tumor growth in injected lesions. Moreover, anti-PD-L1 combination also facilitated abscopal responses in non-injected lesions.
Insights
A novel adenoviral gene therapy, mLOAd703, successfully inflamed resistant melanoma tumors by increasing immune cell infiltration and pro-inflammatory cytokines. Combination therapy with checkpoint inhibitors further enhanced anti-tumor effects and abscopal responses.
Area of Science:
- Oncology
- Immunotherapy
- Gene Therapy
Background:
- Metastatic melanoma treatment resistance is linked to non-T cell inflamed tumors and insufficient dendritic cell (DC) function.
- Dendritic cells are critical for initiating T cell responses against tumors.
Purpose of the Study:
- To evaluate if the adenoviral gene vehicle mLOAd703, encoding DC- and T cell-activating genes, can induce tumor inflammation and overcome resistance to checkpoint inhibitors in a B16-CD46 melanoma model.
- To assess the efficacy of mLOAd703 alone and in combination with checkpoint blockade therapies.
Main Methods:
- Subcutaneous injection of B16-CD46 melanoma cells in C57BL/6J mice.
- Intratumoral administration of mLOAd703, alone or combined with anti-PD-1, anti-PD-L1, or anti-TIM-3 checkpoint inhibitors.
- Analysis of immune cell infiltration (CD8+ T cells, NK cells, CD103+ DCs) and systemic pro-inflammatory cytokines (IFN-γ, TNF-α, IL-27) in tumors, lymph nodes, spleen, and serum.
Main Results:
- mLOAd703 treatment induced infiltration of CD8+ T cells, NK cells, and CD103+ DCs into non-inflamed B16-CD46 tumors.
- Systemic increases in pro-inflammatory cytokines (IFN-γ, TNF-α, IL-27) were observed post-mLOAd703 treatment.
- Combination therapy, particularly with anti-PD-L1 and anti-TIM-3, significantly enhanced tumor growth reduction and induced abscopal responses in non-injected lesions.
Conclusions:
- mLOAd703 effectively converts non-inflamed melanoma tumors into an inflamed state, enhancing immune cell presence and cytokine production.
- Combining mLOAd703 with checkpoint inhibitors, especially anti-PD-L1 and anti-TIM-3, represents a promising strategy to overcome resistance and improve therapeutic outcomes in metastatic melanoma.
