Project description:DNASE1L3, an enzyme highly expressed in DCs, is functionally important for regulating autoimmune responses to self-DNA and chromatin. Deficiency of DNASE1L3 leads to development of autoimmune diseases in both humans and mice. However, despite the well-established causal relationship between DNASE1L3 and immunity, little is known about the involvement of DNASE1L3 in regulation of antitumor immunity, the foundation of modern antitumor immunotherapy. In this study, we identify DNASE1L3 as a potentially new regulator of antitumor immunity and a tumor suppressor in colon cancer. In humans, DNASE1L3 is downregulated in tumor-infiltrating DCs, and this downregulation is associated with poor patient prognosis and reduced tumor immune cell infiltration in many cancer types. In mice, Dnase1l3 deficiency in the tumor microenvironment enhances tumor formation and growth in several colon cancer models. Notably, the increased tumor formation and growth in Dnase1l3-deficient mice are associated with impaired antitumor immunity, as evidenced by a substantial reduction of cytotoxic T cells and a unique subset of DCs. Consistently, Dnase1l3-deficient DCs directly modulate cytotoxic T cells in vitro. To our knowledge, our study unveils a previously unknown link between DNASE1L3 and antitumor immunity and further suggests that restoration of DNASE1L3 activity may represent a potential therapeutic approach for anticancer therapy.
Project description:For the chronic inflammation-related colon cancer model (AOM/DSS-colon cancer model), 3-month-old Dnase1l3 WT and KO mice were injected with AOM (8 mg/kg, body weight). One week later, mice were challenged with 2.5% DSS water for 7 days followed by a 14-day recovery with regular drinking water for three cycles. Body weight, rectal bleeding and diarrhea were monitored during the entire experiment. Mice with more than 25% weight loss were removed during the experiment. For the AOM model, 2-month-old Dnase1l3 WT and KO mice were injected intraperitoneally with AOM (8 mg/kg, body weight). Colon tissues were isolated 9 hours, or five days after injection. All animal experiments were conducted in accordance with guidelines of NIEHS/NIH Animal Care and Use Committee.
Project description:For the chronic inflammation-related colon cancer model (AOM/DSS-colon cancer model), 3-month-old Dnase1l3 WT and KO mice were injected with AOM (8 mg/kg, body weight). One week later, mice were challenged with 2.5% DSS water for 7 days followed by a 14-day recovery with regular drinking water for three cycles. Body weight, rectal bleeding and diarrhea were monitored during the entire experiment. Mice with more than 25% weight loss were removed during the experiment. For the AOM model, 2-month-old Dnase1l3 WT and KO mice were injected intraperitoneally with AOM (8 mg/kg, body weight). Colon tissues were isolated 9 hours, or five days after injection. All animal experiments were conducted in accordance with guidelines of NIEHS/NIH Animal Care and Use Committee.
Project description:Antiangiogenic therapy is a recognized method for countering the immunosuppressive tumor microenvironment (TME) and improving anti-tumor immunity. PB101 is a glycosylated decoy receptor that binds to VEGF-A and PlGF with high affinity, based on the VEGFR1 backbone. Here, we elucidated PB101-induced remodeling of tumor angiogenesis and immunity, which enhances anti-PD-L1 immune checkpoint blockade. PB101 inhibited tumor growth by suppressing angiogenesis and enhancing CD8+ T cell infiltration into the tumors. PB101 induced robust reprogramming of antitumor immunity and activates intratumoral CD8+ T cells. Anti-tumor efficacy of PB101 is mostly dependent on CD8+ T cells and IFN-γ. PB101 reprograms tumor immunity in a manner distinct from that of the conventional VEGF decoy receptor, VEGF-trap. With its potent immune-modulating capability, PB101 synergizes with an anti-PD-L1, triggering strengthened antitumor immunity. Combining PB101 and anti-PD-L1 could establish durable protective immunity against tumor recurrence and metastasis. The findings of this study offer scientific rationales for further clinical development of PB101, particularly when used in combination with immune checkpoint inhibitors, as a potential treatment for advanced cancers.
Project description:The use of large molecules for immunotherapy has led to exciting developments in cancer treatment, such as the development of PD-1/PD-L1 antibodies. However, small molecule targeted therapies still lack effective immune-functional classes. Ideal anticancer drugs should simultaneously generate immune memory when killing cancer cells to prevent tumor relapse and metastasis. To this end, we carried out a rationally designed strategy to develop novel classes of small molecule compounds with bifunctional targeting and immunostimulatory abilities by conjugating targeting compounds with TLR7 agonists, generating immune-targeting conjugates (ImmunTacs). GY161, as a representative ImmunTac, was synthesized via chemical conjugation of ibrutinib with a TLR7 agonist. In vitro, GY161 stimulated the production of cytokines by mouse spleen lymphocytes, promoted the maturation of dendritic cells (DCs), and inhibited the growth and induced the apoptosis of B16 melanoma cells by regulating the c-Met/β-catenin pathway. In vivo, GY161 enhanced the frequency of CD8+ T cells in spleens and tumors, suppressed the growth of B16 melanoma cell-derived tumors and prolonged the survival time of mice. In summary, GY161 could prevent melanoma progression through direct tumor killing and by triggering specific immunity. These results strongly suggest that ImmunTacs are a reliable and promising strategy for developing small molecule immunogenic anticancer drugs.
