Sudocetaxel Zendusortide (TH1902) triggers the cGAS/STING pathway and potentiates anti-PD-L1 immune-mediated tumor cell killing.

The anticancer efficacy of Sudocetaxel Zendusortide (TH1902), a peptide-drug conjugate internalized through a sortilin-mediated process, was assessed in a triple-negative breast cancer-derived MDA-MB-231 immunocompromised xenograft tumor model where complete tumor regression was observed for more than 40 days after the last treatment. Surprisingly, immunohistochemistry analysis revealed high staining of STING, a master regulator in the cancer-immunity cycle. A weekly administration of TH1902 as a single agent in a murine B16-F10 melanoma syngeneic tumor model demonstrated superior tumor growth inhibition than did docetaxel. A net increase in CD45 leukocyte infiltration within TH1902-treated tumors, especially for tumor-infiltrating lymphocytes and tumor-associated macrophages was observed. Increased staining of perforin, granzyme B, and caspase-3 was suggestive of elevated cytotoxic T and natural killer cell activities. Combined TH1902/anti-PD-L1 treatment led to increases in tumor growth inhibition and median animal survival. TH1902 inhibited cell proliferation and triggered apoptosis and senescence in B16-F10 cells in vitro, while inducing several downstream effectors of the cGAS/STING pathway and the expression of MHC-I and PD-L1. This is the first evidence that TH1902 exerts its antitumor activity, in part, through modulation of the immune tumor microenvironment and that the combination of TH1902 with checkpoint inhibitors (anti-PD-L1) could lead to improved clinical outcomes.

Corrigendum: Sudocetaxel Zendusortide (TH1902) triggers the cGAS/STING pathway and potentiates anti-PD-L1 immune-mediated tumor cell killing.

[This corrects the article DOI: 10.3389/fimmu.2024.1355945.].

Elucidating the Role of Ezh2 in Tolerogenic Function of NOD Bone Marrow-Derived Dendritic Cells Expressing Constitutively Active Stat5b.

Tolerogenic dendritic cells (toDCs) are crucial to controlling the development of autoreactive T cell responses and the prevention of autoimmunity. We have reported that NOD.CD11cStat5b-CA transgenic mice expressing a constitutively active (CA) form of Stat5b under the control of a CD11c promoter are protected from diabetes and that Stat5b-CA-expressing DCs are tolerogenic and halt ongoing diabetes in NOD mice. However, the molecular mechanisms by which Stat5b-CA modulates DC tolerogenic function are not fully understood. Here, we used bone marrow-derived DCs (BMDCs) from NOD.CD11cStat5b-CA transgenic mice (Stat5b-CA.BMDCs) and found that Stat5b-CA.BMDCs displayed high levels of MHC class II, CD80, CD86, PD-L1, and PD-L2 and produced elevated amounts of TGFß but low amounts of TNFα and IL-23. Stat5b-CA.BMDCs upregulated Irf4 and downregulated Irf8 genes and protein expression and promoted CD11c+CD11b+ DC2 subset differentiation. Interestingly, we found that the histone methyltransferase Ezh2 and Stat5b-CA bound gamma-interferon activated site (GAS) sequences in the Irf8 enhancer IRF8 transcription, whereas Stat5b but not Ezh2 bound GAS sequences in the Irf4 promoter to enhance IRF4 transcription. Injection of Stat5b-CA.BMDCs into prediabetic NOD mice halted progression of islet inflammation and protected against diabetes. Importantly, inhibition of Ezh2 in tolerogenic Stat5b-CA.BMDCs reduced their ability to prevent diabetes development in NOD recipient mice. Taken together, our data suggest that the active form of Stat5b induces tolerogenic DC function by modulating IRF4 and IRF8 expression through recruitment of Ezh2 and highlight the fundamental role of Ezh2 in Stat5b-mediated induction of tolerogenic DC function.