Androgens in Patients With Luminal B and HER2 Breast Cancer Might Be a Biomarker Promoting Anti-PD-1 Efficacy

Landscape of unconventional γδ T cell subsets in cancer

T cells are broadly categorized into two groups, namely conventional and unconventional T cells. Conventional T cells are the most prevalent and well-studied subset of T cells. On the other hand, unconventional T cells exhibit diverse functions shared between innate and adaptive immune cells. During recent decades, γδ T cells have received attention for their roles in cancer immunity. These cells can detect various molecules, such as lipids and metabolites. Also, they are known for their distinctive ability to recognize and target cancer cells in the tumor microenvironment (TME). This feature of γδ T cells could provide a unique therapeutic tool to fight against cancer. Understanding the role of γδ T cells in TME is essential to prepare the groundwork to use γδ T cells for clinical purposes. Here, we provide recent knowledge regarding the role γδ T cell subsets in different cancer types.

Serum vitamin D deficiency is associated with increased risk of γδ T cell exhaustion in HBV-infected patients

Previous studies have demonstrated that T cell exhaustion is associated with poor clearance of Hepatitis B virus (HBV). However, whether the expression of exhaustion markers on innate-like circulating γδ T cells derived from patients with HBV infection correlates with the serum level of vitamin D is not completely understood. In this study, we found that the frequency of circulating Vδ2+ T cell and serum levels of vitamin 25(OH)D3 were significantly decreased in patients with HBV. And serum 25(OH)D3 levels in HBV-infected patients were negatively correlated with HBV DNA load and PD-1 expression on γδ T cells. Interestingly, 1α,25(OH)2 D3 alleviated the exhaustion phenotype of Vδ2 T cells in HBV-infected patients and promoted IFN-β expression in human cytotoxic Vδ2 T cells in vitro. Collectively, these findings demonstrate that vitamin D plays a pivotal role in reversing γδ T-cell exhaustion and is highly promising target for ameliorating HBV infection.

1α,25(OH)2D3 ameliorates insulin resistance by alleviating γδ T cell inflammation via enhancing fructose-1,6-bisphosphatase 1 expression

Background: Chronic inflammation caused by immune cells is the central link between obesity and insulin resistance. Targeting the inflammatory process is a highly promising method for reversing systemic insulin resistance. Methods: Blood samples were prospectively collected from 68 patients with type 2 diabetes. C57BL/6J mice were fed either a high-fat diet (HFD) or normal chow (NC). We performed phenotypical and functional analyses of immune cells using flow cytometry. Vitamin D receptor (VDR) knockout γδ T cells were constructed using Cas9-gRNA targeted approaches to identify 1α,25(OH)2D3/VDR signaling pathway-mediated transcriptional regulation of fructose-1,6-bisphosphatase (FBP1) in γδ T cells. Results: Serum vitamin D deficiency aggravates inflammation in circulating γδ T cells in type 2 diabetes patients. We defined a critical role for 1α,25(OH)2D3 in regulating glycolysis metabolism, protecting against inflammation, and alleviating insulin resistance. Mechanistically, 1α,25(OH)2D3-VDR promoted FBP1 expression to suppress glycolysis in γδ T cells, thereby inhibiting Akt/p38 MAPK phosphorylation and reducing inflammatory cytokine production. Notably, therapeutic administration of 1α,25(OH)2D3 restrained inflammation in γδ T cells and ameliorated systemic insulin resistance in obese mice. Conclusions: Collectively, these findings show that 1α,25(OH)2D3 plays an important role in maintaining γδ T cell homeostasis by orchestrating metabolic programs, and is a highly promising target for preventing obesity, inflammation, and insulin resistance.

Sex Hormones in Breast Cancer Immunity

Sex hormones, such as estrogens and androgens, regulate genomic and cellular processes that contribute to sex-specific disparities in the pathophysiology of various cancers. Sex hormones can modulate the immune signals and activities of tumor cells and tumor-associated leukocytes to support or suppress cancer progression. Therefore, hormonal differences between males and females play a crucial role in cancer immunity and in the response to therapies that exploit the intrinsic immune system to eliminate malignant cells. In this review, we summarize the impact of sex hormones in the breast cancer microenvironment, with a focus on how the hormonal environment affects tumor immunity. We also discuss the potential benefits of endocrine therapy used in combination with immunotherapy to strengthen the antitumor immune response.