Class A CpG oligodeoxynucleotide inhibits IFN-γ-induced signaling and apoptosis in lung cancer

Uncovering the complex role of interferon-gamma in suppressing type 2 immunity to cancer

Cancer involves cells' abnormal growth and ability to invade or metastasize to different body parts. Cancerous cells can divide uncontrollably and spread to other areas through the lymphatic or circulatory systems. Tumors form when malignant cells clump together in an uncontrolled manner. In this context, the cytokine interferon-gamma (IFN-γ) is crucial in regulating immunological responses, particularly malignancy. While IFN-γ is well-known for its potent anti-tumor effects by activating type 1 immunity, recent research has revealed its ability to suppress type 2 immunity, associated with allergy and inflammatory responses. This review aims to elucidate the intricate function of IFN-γ in inhibiting type 2 immune responses to cancer. We explore how IFN-γ influences the development and function of immune cells involved in type 2 immunity, such as mast cells, eosinophils, and T-helper 2 (Th2) cells. Additionally, we investigate the impact of IFN-mediated reduction of type 2 immunity on tumor development, metastasis, and the response to immunotherapeutic interventions. To develop successful cancer immunotherapies, it is crucial to comprehend the complex interplay between type 2 and type 1 immune response and the regulatory role of IFN-γ. This understanding holds tremendous promise for the development of innovative treatment approaches that harness the abilities of both immune response types to combat cancer. However, unraveling the intricate interplay between IFN-γ and type 2 immunity in the tumor microenvironment will be essential for achieving this goal.

Role of interferon-gamma (IFN-γ) and IFN-γ receptor 1/2 (IFNγR1/2) in regulation of immunity, infection, and cancer development: IFN-γ-dependent or independent pathway

IFN-γ, a soluble cytokine being produced by T lymphocytes, macrophages, mucosal epithelial cells, or natural killer cells, is able to bind to the IFN-γ receptor (IFNγR) and in turn activate the Janus kinase (JAK)-signal transducer and transcription protein (STAT) pathway and induce expression of IFN-γ-stimulated genes. IFN-γ is critical for innate and adaptive immunity and aberrant IFN-γ expression and functions have been associated with different human diseases. However, the IFN-γ/IFNγR signaling could be a double-edged sword in cancer development because the tissue microenvironments could determine its anti- or pro-tumorigenic activities. The IFNγR protein consists of two IFNγR1 and IFNγR2 chains, subunits of which play different roles under certain conditions. This review assessed IFNγR polymorphisms, expression and functions in development and progression of various human diseases in an IFN-γ-dependent or independent manner. This review also discussed tumor microenvironment, microbial infection, and vital molecules in the IFN-γ upstream signaling that might regulate IFNγR expression, drug resistance, and druggable strategy, to provide evidence for further application of IFNγR.

T-cell response to phytohemagglutinin in the interferon-γ release assay as a potential biomarker for the response to immune checkpoint inhibitors in patients with non-small cell lung cancer

Background

Immune checkpoint inhibitors are a standard treatment for advanced lung cancer, although it remains important to identify biomarkers that can accurately predict treatment response. Immune checkpoint inhibitors enhance the antitumor T‐cell response, and interferon‐γ plays an important role in this process. Therefore, this study evaluated whether the number of interferon‐γ‐releasing peripheral T cells after phytohemagglutinin stimulation in the interferon‐γ release assay might act as a biomarker for the response of non‐small cell lung cancer to immune checkpoint inhibitor treatment.

Methods

Data were retrospectively collected regarding 74 patients with non‐small cell lung cancer who had received immune checkpoint inhibitors. Pretreatment screening tests had been performed using the T‐SPOT.TB assay, which quantifies the number of interferon‐γ‐releasing T cells (as immunospots) in response to phytohemagglutinin and tuberculosis‐specific antigen stimulation. Clinical factors and the number of spots in the T‐SPOT fields were evaluated for associations with patient outcomes. The median number of spots was used to categorize patients as having high or low values, and the two groups were compared.

Results

Relative to patients with a low ratio, patients with a high ratio of phytohemagglutinin/tuberculosis‐specific antigen spots (i.e. more responsive T cells) had significantly better progression‐free survival after immune checkpoint inhibitor treatment. When we only considered patients with negative T‐SPOT results, a high number of phytohemagglutinin‐stimulated spots corresponded to significantly longer progression‐free survival.

Conclusion

The T‐SPOT.TB assay can be used to quantify the number of immunospots in response to antigen stimulation, which may predict the response to immune checkpoint inhibitors in patients with non‐small cell lung cancer.