Dual Programmed Death Receptor‐1 and Vascular Endothelial Growth Factor Receptor‐2 Blockade Promotes Vascular Normalization and Enhances Antitumor Immune Responses in Hepatocellular Carcinoma

Abstract

Background and Aims Activation of the antitumor immune response using programmed death receptor‐1 (PD‐1) blockade showed benefit only in a fraction of patients with hepatocellular carcinoma (HCC). Combining PD‐1 blockade with antiangiogenesis has shown promise in substantially increasing the fraction of patients with HCC who respond to treatment, but the mechanism of this interaction is unknown. Approach and Results We recapitulated these clinical outcomes using orthotopic—grafted or induced—murine models of HCC. Specific blockade of vascular endothelial receptor 2 (VEGFR‐2) using a murine antibody significantly delayed primary tumor growth but failed to prolong survival, while anti‐PD‐1 antibody treatment alone conferred a minor survival advantage in one model. However, dual anti‐PD‐1/VEGFR‐2 therapy significantly inhibited primary tumor growth and doubled survival in both models. Combination therapy reprogrammed the immune microenvironment by increasing cluster of differentiation 8–positive (CD8+) cytotoxic T cell infiltration and activation, shifting the M1/M2 ratio of tumor‐associated macrophages and reducing T regulatory cell (Treg) and chemokine (C‐C motif) receptor 2–positive monocyte infiltration in HCC tissue. In these models, VEGFR‐2 was selectively expressed in tumor endothelial cells. Using spheroid cultures of HCC tissue, we found that PD‐ligand 1 expression in HCC cells was induced in a paracrine manner upon anti‐VEGFR‐2 blockade in endothelial cells in part through interferon‐gamma expression. Moreover, we found that VEGFR‐2 blockade increased PD‐1 expression in tumor‐infiltrating CD4+ cells. We also found that under anti‐PD‐1 therapy, CD4+ cells promote normalized vessel formation in the face of antiangiogenic therapy with anti‐VEGFR‐2 antibody. Conclusions We show that dual anti‐PD‐1/VEGFR‐2 therapy has a durable vessel fortification effect in HCC and can overcome treatment resistance to either treatment alone and increase overall survival in both anti‐PD‐1 therapy–resistant and anti‐PD‐1 therapy–responsive HCC models.

Combining microenvironment normalization strategies to improve cancer immunotherapy

“…Our model predictions are further validated by recent clinical trials showing that combination treatment with a low dose of an anti-angiogenic agent (regorafenib) with nivolumab is superior to high doses in advanced gastric or colorectal cancer (60). Our model suggests that administration of immunotherapy with anti-angiogenic treatment could protect blood vessels from excessive pruning (49). However, the extent of ICB-induced normalization is likely to vary with tumor type, stage of disease, and location, and it might not even occur in some tumor types.…”

“…To compare model predictions with experimental data, all model parameters were kept the same as derived separately from pertinent studies. The sole model parameter that was adjusted to fit the experimental data (19,24,26,36,49) was k 1 , which describes the dependence of cancer cell proliferation on oxygen concentration (SI Appendix, Table S2). The value of k 1 was determined so that the predicted final tumor volume matched the experimental value of one of the treatment groups, and it was kept the same for comparison of model predictions against all experimental data from all groups of the same study.…”

“…3B. Shigeta et al (49) demonstrated that dual anti-PD-1/anti-VEGFR-2 (antiangiogenic) therapy has a durable vessel fortification effect in hepatocellular carcinoma (HCC) models and can overcome resistance to antiangiogenic therapy and immunotherapy. Specifically, they found that combination treatment improves efficacy by increasing the fraction of mature vessels, increasing T cell infiltration and activation, and shifting the ratio of M1-like to M2-like TAMs.…”

“…1). We simulate how antiangiogenic, stroma normalization, and immunotherapy treatments affect model components and compare model predictions with previous experimental studies (19,24,26,36,49). Furthermore, we use model predictions to provide guidelines for the optimal use of these three strategies and point out the gaps in our understanding.…”

Interplay Between Macrophages and Angiogenesis: A Double-Edged Sword in Liver Disease

“…Hepatocellular carcinoma is the most common type of primary liver cancer and the third leading cause of death related to cancer in the world. Macrophages contribute to growth, angiogenesis, and metastasis in hepatocellular carcinoma (57,58). Although macrophages resolutely contribute to tumor surveillance they generally become tumor associated macrophages (TAM), which are highly pro-inflammatory, and provide the necessary signals to create a pro-tumorigenic environment and to inhibit immune responses against it (59) (Figure 4).…”