Chemotherapy Induces Intratumoral Expression of Chemokines in Cutaneous Melanoma, Favoring T-cell Infiltration and Tumor Control

101 Background: Cancers of the head and neck (HNC) represent some of the most debilitating and aggressive tumors. Radiotherapy (RT) is the primary treatment modality for locally advanced HNC, but less than 50% of patients treated with RT survive to 5 years. Clinical trials with the immune checkpoint inhibitor PD-L1 have shown considerable promise, but on its own has only yielded a 20% response rate. RT has the potential to transform the tumor microenvironment promoting infiltration of T-cells in poorly immunogenic tumors and activating T-cells in tumors with pre-existing T-cell populations. We hypothesized that the combination of PD-L1 inhibition with radiation can enhance therapeutic efficacy through re-invigoration of exhausted T-cells. Methods: Tumor cells were injected into the right buccal mucosa. Treatment was initiated when established tumors were observed. Forty mice per tumor model were randomized to IgG2b control, anti PD-L1, RT alone or RT+anti PD-L1. Anti PD-L1 was started 3 days before RT (single dose of 10Gy) and maintained for 3 weeks. For mechanistic studies, mice received the same treatment but were euthanized 72 hours after RT. Flow cytometric analysis of T-cell expression of PD-1, CTLA-4, FOXP3, CD44 and IFNG was performed on freshly harvested tumors and regional lymph nodes. Results: Tumor-bearing mice formed aggressive tumors with regional lymph node metastasis. Mice treated with RT or anti PD-L1 had slightly improved survival whereas mice treated with RT+anti-PD-L1 had significantly improved survival (p = 0.0007). Tumor control was significantly improved in the RT+anti-PD-L1 group compared to other groups. Anti PD-L1 alone did not improve tumor control. Average tumor volume on day 23 was 175±60.1 mm3 in the RT+anti-PD-L1 group compared to 623±91.0 mm3 in the PD-L1 group. Flow cytometric analysis revealed that this is mediated by enhancement in T-cell infiltration. Analysis of T-cell activation showed increased expression of CD44 and IFNG. Conclusions: Our results show a critical role for RT in mediating sensitivity to PD-L1 inhibition in HNC. In combination with anti PD-L1, RT significantly increased survival and tumor control compared to either modality alone.

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Modulating tumor infiltrating myeloid cells to enhance bispecific antibody-driven T cell infiltration and anti-tumor response

Journal of Hematology & Oncology ◽

10.1186/s13045-021-01156-5 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Jeong A. Park ◽

Linlin Wang ◽

Nai-Kong V. Cheung

Keyword(s):

T Cells ◽

T Cell ◽

Bispecific Antibody ◽

Tumor Response ◽

Human Cancer ◽

Myeloid Cells ◽

Human Tumor ◽

Cell Infiltration ◽

Tumor Control ◽

T Cell Infiltration

Abstract Background Tumor microenvironment (TME) is a dynamic cellular milieu to promote tumor angiogenesis, growth, proliferation, and metastasis, while derailing the host anti-tumor response. TME impedes bispecific antibody (BsAb) or chimeric antigen receptor (CAR)-driven T cells infiltration, survival, and cytotoxic efficacy. Modulating tumor infiltrating myeloid cells (TIMs) could potentially improve the efficacy of BsAb. Methods We evaluated the effects of TIM modulation on BsAb-driven T cell infiltration into tumors, their persistence, and in vivo anti-tumor response. Anti-GD2 BsAb and anti-HER2 BsAb built on IgG-[L]-scFv platform were tested against human cancer xenografts in BALB-Rag2−/−IL-2R-γc-KO (BRG) mice. Depleting antibodies specific for polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC), monocytic MDSC (M-MDSC), and tumor associated macrophage (TAM) were used to study the role of each TIM component. Dexamethasone, an established anti-inflammatory agent, was tested for its effect on TIMs. Results BsAb-driven T cells recruited myeloid cells into human tumor xenografts. Each TIM targeting therapy depleted cells of interest in blood and in tumors. Depletion of PMN-MDSCs, M-MDSCs, and particularly TAMs was associated with enhanced T cell infiltration into tumors, significantly improving tumor control and survival in multiple cancer xenograft models. Dexamethasone premedication depleted monocytes in circulation and TAMs in tumors, enhanced BsAb-driven T cell infiltration, and anti-tumor response with survival benefit. Conclusion Reducing TIMs markedly enhanced anti-tumor effects of BsAb-based T cell immunotherapy by improving intratumoral T cell infiltration and persistence. TAM depletion was more effective than PMN- or M-MDSCs depletion at boosting the anti-tumor response of T cell engaging BsAb.

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DNA Vaccines Targeting Novel Cancer-Associated Antigens Frequently Expressed in Head and Neck Cancer Enhance the Efficacy of Checkpoint Inhibitor

Frontiers in Immunology ◽

10.3389/fimmu.2021.763086 ◽

2021 ◽

Vol 12 ◽

Author(s):

Chuan Wang ◽

Nur Syafinaz Zainal ◽

San Jiun Chai ◽

James Dickie ◽

Chai Phei Gan ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Tumor Growth ◽

Head And Neck ◽

Dna Vaccines ◽

Checkpoint Inhibitors ◽

Cell Infiltration ◽

Tumor Control ◽

Preclinical Model ◽

T Cell Infiltration

HPV-independent head and neck squamous cell carcinoma (HNSCC) is a common cancer globally. The overall response rate to anti-PD1 checkpoint inhibitors (CPIs) in HNSCC is ~16%. One major factor influencing the effectiveness of CPI is the level of tumor infiltrating T cells (TILs). Converting TILlow tumors to TILhigh tumors is thus critical to improve clinical outcome. Here we describe a novel DNA vaccines to facilitate the T-cell infiltration and control tumor growth. We evaluated the expression of target antigens and their respective immunogenicity in HNSCC patients. The efficacy of DNA vaccines targeting two novel antigens were evaluated with or without CPI using a syngeneic model. Most HNSCC patients (43/44) co-expressed MAGED4B and FJX1 and their respective tetramer-specific T cells were in the range of 0.06-0.12%. In a preclinical model, antigen-specific T cells were induced by DNA vaccines and increased T cell infiltration into the tumor, but not MDSC or regulatory T cells. The vaccines inhibited tumor growth and improved the outcome alone and upon combination with anti-PD1 and resulted in tumor clearance in approximately 75% of mice. Pre-existence of MAGED4B and FJX1-reactive T cells in HNSCC patients suggests that these widely expressed antigens are highly immunogenic and could be further expanded by vaccination. The DNA vaccines targeting these antigens induced robust T cell responses and with the anti-PD1 antibody conferring excellent tumor control. This opens up an opportunity for combination immunotherapy that might benefit a wider population of HNSCC patients in an antigen-specific manner.

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