A Fc-VEGF chimeric fusion enhances PD-L1 immunotherapy via inducing immune reprogramming and infiltration in the immunosuppressive tumor microenvironment.

BACKGROUND: Immunotherapy is an emerging cancer therapy with potential great success; however, immune checkpoint inhibitor (e.g., anti-PD-1) has response rates of only 10-30% in solid tumor because of the immunosuppressive tumor microenvironment (TME). This affliction can be solved by vascular normalization and TME reprogramming. METHODS: By using the single-cell RNA sequencing (scRNAseq) approach, we tried to find out the reprogramming mechanism that the Fc-VEGF chimeric antibody drug (Fc-VFD) enhances immune cell infiltration in the TME. RESULTS: In this work, we showed that Fc-VEGF121-VEGF165 (Fc-VEGF chimeric antibody drug, Fc-VFD) arrests excess angiogenesis and tumor growth through vascular normalization using in vitro and in vivo studies. The results confirmed that the treatment of Fc-VFD increases immune cell infiltration including cytotoxic T, NK, and M1-macrophages cells. Indeed, Fc-VFD inhibits Lon-induced M2 macrophages polarization that induces angiogenesis. Furthermore, Fc-VFD inhibits the secretion of VEGF-A, IL-6, TGF-ß, or IL-10 from endothelial, cancer cells, and M2 macrophage, which reprograms immunosuppressive TME. Importantly, Fc-VFD enhances the synergistic effect on the combination immunotherapy with anti-PD-L1 in vivo. CONCLUSIONS: In short, Fc-VFD fusion normalizes intratumor vasculature to reprogram the immunosuppressive TME and enhance cancer immunotherapy.

Capsaicin Inhibited Aggressive Phenotypes through Downregulation of Tumor-Associated NADH Oxidase (tNOX) by POU Domain Transcription Factor POU3F2.

Capsaicin has been reported to preferentially inhibit the activity of tumor-associated NADH oxidase (tNOX), which belongs to a family of growth-related plasma membrane hydroquinone oxidases in cancer/transformed cells. The inhibitory effect of capsaicin on tNOX is associated with cell growth attenuation and apoptosis. However, no previous study has examined the transcriptional regulation of tNOX protein expression. Bioinformatic analysis has indicated that the tNOX promoter sequence harbors a binding motif for POU3F2, which is thought to play important roles in neuronal differentiation, melanocytes growth/differentiation and tumorigenesis. In this study, we found that capsaicin-mediated tNOX downregulation and cell migration inhibition were through POU3F2. The protein expression levels of POU3F2 and tNOX are positively correlated, and that overexpression of POU3F2 (and the corresponding upregulation of tNOX) enhanced the proliferation, migration and invasion in AGS (human gastric carcinoma) cells. In contrast, knockdown of POU3F2 downregulates tNOX, and the cancer phenotypes are affected. These findings not only shed light on the molecular mechanism of the anticancer properties of capsaicin, but also the transcription regulation of tNOX expression that may potentially explain how POU3F2 is associated with tumorigenesis.

Synthesis and Characterization of 4,11-Diaminoanthra[2,3-b]furan-5,10-diones: Tumor Cell Apoptosis through tNOX-Modulated NAD(+)/NADH Ratio and SIRT1.

A series of new 4,11-diaminoanthra[2,3-b]furan-5,10-dione derivatives with different side chains were synthesized. Selected 2-unsubstituted derivatives 11-14 showed high antiproliferative potency on a panel of mammalian tumor cell lines including multidrug resistance variants. Compounds 11-14 utilized multiple mechanisms of cytotoxicity including inhibition of Top1/Top2-mediated DNA relaxation, reduced NAD(+)/NADH ratio through tNOX inhibition, suppression of a NAD(+)-dependent sirtuin 1 (SIRT1) deacetylase activity, and activation of caspase-mediated apoptosis. Here, for the first time, we report that tumor-associated NADH oxidase (tNOX) and SIRT1 are important cellular targets of antitumor anthracene-9,10-diones.