Jun Ishihara

Osteosarcoma (OS) is the most prevalent primary bone malignancy in children and adolescents; however, therapeutic outcomes remain suboptimal due to tumor heterogeneity, chemoresistance, and inadequate immune activation. Doxorubicin (Dox), the standard therapy that induces immunogenic cell death, has its efficacy compromised by the immunosuppressive tumor microenvironment (TME). While interleukin-12 (IL-12) can activate and recruit various immune cells, making it an attractive combination partner, its systemic delivery is severely limited by dose-limiting toxicity. We have previously reported that intravenous injection of A3 collagen binding domain (CBD) of von Willebrand Factor preferentially accumulates into the TME of various tumor models enriched in collagen I and III. Furthermore, CBD-fused IL-12 (CBD-IL-12) demonstrated superior therapeutic effects against various cancer models compared to unmodified IL-12 due to its collagen-targeted delivery and the resulting tumor-localized inflammation. Given that the OS TME also exhibits higher collagen I and III expression compared to normal bone, we hypothesized that a CBD-IL-12 fusion protein could showcase potent anti-tumor efficacy in OS via tumor-specific accumulation. Here, we demonstrated that CBD-IL-12 exhibited 4-fold enhanced tumor accumulation compared to unmodified IL-12 and increased cytotoxic T cell infiltration by 2.2-fold within the immune-cold microenvironment in a mouse model of OS. The combination of CBD-IL-12 with Dox significantly prolonged median survival in two independent murine OS models. This coordinated approach utilizing Dox coupled with precision-targeted IL-12 immunotherapy represents a clinically translatable strategy that overcomes the inherent limitations of single-agent treatments for OS. Highlight: Collagen-targeted IL-12 increases tumor accumulation in osteosarcoma. The collagen-targeted IL-12 synergizes with doxorubicin in osteosarcoma models. Combination therapy enhances T cell differentiation and activates innate immunity.

Liposomal or polymeric nanoparticles have been instrumental in improving delivery of poorly soluble chemotherapeutics and those with dose limiting toxicity such as doxorubicin (DOX). More recently, nanoformulations have shown to...

Immunosuppressive microenvironments, the lack of immune infiltration, and antigen heterogeneity pose challenges for chimaeric antigen receptor (CAR)-T cell therapies applied to solid tumours. Previously, CAR-T cells were armoured with immunostimulatory molecules, such as interleukin 12 (IL-12), to overcome this issue, but faced high toxicity. Here we show that collagen-binding domain-fused IL-12 (CBD-IL-12) secreted from CAR-T cells to target human six transmembrane epithelial antigen of prostate 1 (STEAP1) is retained within murine prostate tumours. This leads to high intratumoural interferon-γ levels, without hepatotoxicity and infiltration of T cells into non-target organs compared with unmodified IL-12. Both innate and adaptive immune compartments are activated and recognize diverse tumour antigens after CBD-IL-12-armoured CAR-T cell treatment. A combination of CBD-IL-12-armoured CAR-T cells and immune checkpoint inhibitors eradicated large tumours in an established prostate cancer mouse model. In addition, human CBD-IL-12-armoured CAR-T cells showed potent anti-tumour efficacy in a 22Rv1 xenograft while reducing circulating IL-12 levels compared with unmodified IL-12-armoured CAR-T cells. CBD fusion to potent payloads for CAR-T therapy may remove obstacles to their clinical translation towards elimination of solid tumours.

Chimeric antigen receptor (CAR)-T cell efficacy in solid tumours is limited due in part to the immunosuppressive tumour microenvironment (TME). To improve antitumour responses, we hypothesized that enabling CAR-T cells to secrete bifunctional fusion proteins consisting of a cytokine modifier such as TGFβ^trap, IL-15 or IL-12, combined with an immune checkpoint inhibitor such as αPD-L1, would provide tumour-localized immunomodulation to improve CAR-T cell functionality. Here we engineer CAR-T cells to secrete TGFβ^trap, IL-15 or IL-12 molecules fused to αPD-L1 scFv and assess in vitro functionality and in vivo safety and efficacy in prostate and ovarian cancer models. CAR-T cells engineered with αPD-L1–IL-12 are superior in safety and efficacy compared with CAR-T cells alone and those engineered with αPD-L1 fused with TGFβ^trap or IL-15. Further, αPD-L1–IL-12 engineered CAR-T cells improve T cell trafficking and tumour infiltration, and localize IFNγ production, TME modulation and antitumour responses, with reduced systemic inflammation-associated toxicities. We believe our αPD-L1–IL-12 engineering strategy presents an opportunity to improve CAR-T cell clinical efficacy and safety across multiple solid tumour types.

Immunosuppressive microenvironments, the lack of immune infiltration, and antigen heterogeneity pose significant challenges for chimeric antigen receptor (CAR)-T cell therapies to tackle solid tumors. CAR-T cells were armed with immunostimulatory payloads, such as interleukin-12 (IL-12), to overcome this issue, but faced intolerable toxicity during clinical development. Here, we show that collagen-binding domain-fused IL-12 (CBD-IL-12) was retained within syngeneic murine prostate tumors, after secretion from CAR-T cells targeting human six transmembrane epithelial antigen of the prostate 1 (STEAP1). This led to equivalently high intratumoral interferon-γ levels without hepatotoxicity and infiltration of T cells into non-target organs, compared with unmodified IL-12. Both innate and adaptive immune compartments were dramatically activated and recognized diverse tumor antigens after CBD-IL-12 CAR-T cell treatment. Combination immunotherapy of CBD-IL-12 CAR-T cells and immune checkpoint inhibitors eradicated large tumors in an established prostate cancer model, without pre-conditioning chemotherapy. The therapy generated anti-tumor immunological memory. CBD-fusion to potent yet toxic payloads of CAR-T therapy may remove obstacles to their clinical translation towards elimination of solid tumors.

Background: The use of immune checkpoint inhibitors (CPIs) has become a dominant regimen in modern cancer therapy, however immune resistance induced by tumor-associated macrophages (TAMs) with immune suppressive and evasion properties limits responses. Therefore, the rational design of immune modulators that can control the immune suppressive properties of TAMs and polarize them, as well as dendritic cells (DCs), toward a more proinflammatory phenotype is a principal objective in cancer immunotherapy. Methods: Here, using a protein engineering approach to enhance cytokine residence in the tumor microenvironment, we examined combined stimulation of the myeloid compartment via tumor stroma-binding granulocyte–macrophage colony-stimulating factor (GM-CSF) to enhance responses in both DCs and T cells via stroma-binding interleukin-12 (IL-12). We evaluated tumor responses at the levels of outcome, cellular responses, and cytokine responses in both the tumors and the tumor-draining lymph nodes. We further investigated the potentiation of DC response to IL-12 by GM-CSF stimulation ex vivo. Results: Engineered GM-CSF restored an antitumorigenic tumor myeloid microenvironment otherwise suppressed by TAMs, while engineered IL-12 provided effector signals to T cells, thereby boosting both tumor-resident antitumor macrophage and CD8⁺ T cell populations. Furthermore, engineered GM-CSF potentiated DC response to IL-12, upregulating DC expression of IL-12 receptor and enhancing their expression of proinflammatory cytokines and chemokines on IL-12 exposure. This resulted in remarkable synergistic efficacy in multiple solid tumor models treated with the dual cytokine combination. The combination therapy also improved the efficacy of CPI in a CPI-resistant genetically-engineered melanoma model and exhibited synergistic antitumor efficacy in a pulmonary metastasis model. Conclusion: Our strategy provides a rational design for combination immunotherapy targeting both myeloid and lymphoid compartments through complementary mechanisms.

Cancer immunotherapy is moving toward combination regimens with agents of complementary mechanisms of action to achieve more frequent and robust efficacy. However, compared with single-agent therapies, combination immunotherapies are associated with increased overall toxicity because the very same mechanisms also work in concert to enhance systemic inflammation and promote off-tumor toxicity. Therefore, rational design of combination regimens that achieve improved antitumor control without exacerbated toxicity is a main objective in combination immunotherapy. Here, we show that the combination of engineered, tumor matrix-binding interleukin-7 (IL-7) and IL-12 achieves remarkable anticancer effects by activating complementary pathways without inducing any additive immunotoxicity. Mechanistically, engineered IL-12 provided effector properties to T cells, while IL-7 prevented their exhaustion and boosted memory formation as assessed by tumor rechallenge experiments. The dual combination also rendered checkpoint inhibitor (CPI)–resistant genetically engineered melanoma model responsive to CPI. Thus, our approach provides a framework of evaluation of rationally designed combinations in immuno-oncology and yields a promising therapy.

Non-healing wounds have a negative impact on quality of life and account for many cases of amputation and even early death among patients. Diabetic patients are the predominate population affected by these non-healing wounds. Despite the significant clinical demand, treatment with biologics has not broadly impacted clinical care. Interleukin-4 (IL-4) is a potent modulator of the immune system, capable of skewing macrophages towards a pro-regeneration phenotype (M2) and promoting angiogenesis, but can be toxic after frequent administration and is limited by its short half-life and low bioavailability. Here, we demonstrate the design and characterization of an engineered recombinant interleukin-4 construct. We utilize this collagen-binding, serum albumin-fused IL-4 variant (CBD-SA-IL-4) delivered in a hyaluronic acid (HA)-based gel for localized application of IL-4 to dermal wounds in a type 2 diabetic mouse model known for poor healing as proof-of-concept for improved tissue repair. Our studies indicate that CBD-SA-IL-4 is retained within the wound and can modulate the wound microenvironment through induction of M2 macrophages and angiogenesis. CBD-SA-IL-4 treatment significantly accelerated wound healing compared to native IL-4 and HA vehicle treatment without inducing systemic side effects. This CBD-SA-IL-4 construct can address the underlying immune dysfunction present in the non-healing wound, leading to more effective tissue healing in the clinic.