Combining antiangiogenic therapy with immune checkpoint blockade shows significant clinical benefits in various cancers. However, the precise mechanisms driving the antitumor immune response during these treatments have remained unclear until now. Specifically, a recent study using preclinical colorectal cancer models examined the effects of combined VEGFR-2 and PD-1 blockade. Recently, researchers discovered that CD8 T cells respond early to VEGFR-2 inhibition, even before they gain full cytotoxic function. Instead of acting solely as killers, these cells expand and produce interleukin-10 (IL-10) shortly after treatment starts.

While many scientists traditionally view IL-10 as an immunosuppressive cytokine, this study reveals a different, essential function. In fact, CD8 T cell-derived IL-10 acts as a recruiter that brings natural killer (NK) cells into the tumor microenvironment. Consequently, this step is essential for establishing an effective immune landscape within the tumor.

Enhancing the Antitumor Immune Response via IL-10

Furthermore, the recruited NK cells soon gain effector activity. Moreover, they produce granulocyte-macrophage colony-stimulating factor (GM-CSF). Therefore, this factor supports macrophage maturation and the subsequent induction of the chemokine CXCL11. Subsequently, this sequence of events enhances a second wave of CD8 T-cell infiltration. As a result, the treatment sustains long-term immune activity and tumor control.

Additionally, the researchers found that disrupting IL-10 signaling or NK-cell function completely eliminates the therapeutic benefit of the dual blockade. Accordingly, this specific immune program is a mandatory requirement for clinical efficacy. In contrast, the study also noted that depleting regulatory T cells could further improve tumor control. Ultimately, these findings define a unique and unanticipated immune sequence initiated by angiogenesis inhibition that coordinates both innate and adaptive immunity.

What is the role of IL-10 in this combination therapy?

Interleukin-10, produced by early-responding CD8 T cells, serves to recruit natural killer (NK) cells into the tumor site. This recruitment is a critical first step in establishing a durable and effective immune environment.

Why is the recruitment of NK cells important?

NK cells produce GM-CSF, which promotes macrophage maturation and the secretion of CXCL11. This cascade eventually leads to more effective secondary CD8 T-cell infiltration and improved tumor suppression.

Disclaimer: This content is for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Refer to the latest local and national guidelines for clinical practice.

References

1. Geindreau M et al. IL-10 secretion by CD8 T cells orchestrates early NK cell recruitment and antitumor immunity after anti-VEGFR-2/PD-1 therapy. J Immunother Cancer. 2026 Jun 22. doi: undefined. PMID: 42331382.
2. Huang Y, et al. Vascular normalizing doses of antiangiogenic therapy enhance immunotherapy by promoting T-cell infiltration and activation. Proc Natl Acad Sci U S A. 2012;109(43):17561-17566.