The Combination of Anti-CD47 Antibody with CTLA4 Blockade Enhances Anti-Tumor Immunity in Non-Small Cell Lung Cancer via Normalization of Tumor Vasculature and Reprogramming of the Immune Microenvironment.

In solid tumors, the formidable anti-tumor impact resulting from blocking the "don't eat me" signal, arising from CD47-SIRPα interaction, is constrained, especially compared to its efficacy in hematopoietic malignancies. Activating macrophage anti-tumor activity not only necessitates the inhibition of the "don't eat me" signal, but also the activation of the "eat me" (pre-phagocyte) signal. Intriguingly, the cytotoxic T-lymphocyte-associated antigen 4 (CTLA4) antibody (Ab) has been identified to stimulate Fc receptor-mediated active phagocytes in the tumor microenvironment, thereby generating "eat me" signals. This study postulates that concurrently targeting CD47 and CTLA4 could intensify the anti-tumor effects by simultaneously blocking the "don't eat me" signal while triggering the "eat me" signal. The experimental data from this investigation confirm that the combined targeting of CD47 and CTLA4 enhances immunity against solid tumors in LLC cell-transplanted tumor-bearing mice. This effect is achieved by reducing myeloid-derived suppressor cell infiltration while increasing the presence of effector memory CD8+ T cells, NK1.1+ CD8+ T cells, and activated natural killer T cells. Meanwhile, combination therapy also alleviated anemia. Mechanistically, the anti-CD47 Ab is shown to upregulate CTLA4 levels in NSCLC cells by regulating Foxp1. Furthermore, targeting CD47 is demonstrated to promote tumor vascular normalization through the heightened infiltration of CD4+ T cells. These findings suggest that the dual targeting of CD47 and CTLA4 exerts anti-tumor effects by orchestrating the "eat me" and "don't eat me" signals, reshaping the immune microenvironment, and fostering tumor vascular normalization. This combined therapeutic approach emerges as a potent strategy for effectively treating solid tumors.

Significance of the cGAS-STING Pathway in Health and Disease.

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway plays a significant role in health and disease. In this pathway, cGAS, one of the major cytosolic DNA sensors in mammalian cells, regulates innate immunity and the STING-dependent production of pro-inflammatory cytokines, including type-I interferon. Moreover, the cGAS-STING pathway is integral to other cellular processes, such as cell death, cell senescence, and autophagy. Activation of the cGAS-STING pathway by "self" DNA is also attributed to various infectious diseases and autoimmune or inflammatory conditions. In addition, the cGAS-STING pathway activation functions as a link between innate and adaptive immunity, leading to the inhibition or facilitation of tumorigenesis; therefore, research targeting this pathway can provide novel clues for clinical applications to treat infectious, inflammatory, and autoimmune diseases and even cancer. In this review, we focus on the cGAS-STING pathway and its corresponding cellular and molecular mechanisms in health and disease.