An emerging approach for treating cancer involves programming patient-derived T cells with genes encoding disease-specific chimeric antigen receptors (CARs), so that they can combat tumour cells once they are reinfused. Although trials of this therapy have produced impressive results, the in vitro methods they require to generate large numbers of tumour-specific T cells are too elaborate for widespread application to treat cancer patients. Here, we describe a method to quickly program circulating T cells with tumour-recognizing capabilities, thus avoiding these complications. Specifically, we demonstrate that DNA-carrying nanoparticles can efficiently introduce leukaemia-targeting CAR genes into T-cell nuclei, thereby bringing about long-term disease remission. These polymer nanoparticles are easy to manufacture in a stable form, which simplifies storage and reduces cost. Our technology may therefore provide a practical, broadly applicable treatment that can generate anti-tumour immunity ‘on demand’ for oncologists in a variety of settings.

Although adoptive T cell therapy holds promise for the treatment of many cancers, its clinical utility has been limited by problems in delivering targeted lymphocytes to tumor sites, and their inefficient expansion in the immunosuppressive tumor microenvironment. Here we describe a bioactive polymer implant capable of delivering, expanding and dispersing tumor-reactive T cells. The approach can be used to treat inoperable or incompletely-removed tumors by situating implants near them, or at resection sites. Using a mouse breast cancer resection model, we show that the implants effectively support tumor-targeting T cells throughout resection beds and associated lymph nodes, and reduce tumor relapse compared to conventional delivery modalities. In a multifocal ovarian cancer model, we demonstrate that polymer-delivered T cells trigger regression whereas injected tumor-reactive lymphocytes have little curative effect. Scaffold-based T cell delivery may provide a viable treatment option for inoperable tumors, and reduce the rate of metastatic relapse after surgery.

Tumor-associated macrophages (TAMs) usually express an M2 phenotype, which enables them to perform immunosuppressive and tumor-promoting functions. Reprogramming these TAMs toward an M1 phenotype could thwart their pro-cancer activities and unleash anti-tumor immunity, but efforts to accomplish this are nonspecific and elicit systemic inflammation. Here we describe a targeted nanocarrier that can deliver in vitro-transcribed mRNA encoding M1-polarizing transcription factors to reprogram TAMs without causing systemic toxicity. We demonstrate in models of ovarian cancer, melanoma, and glioblastoma that infusions of nanoparticles formulated with mRNAs encoding interferon regulatory factor 5 in combination with its activating kinase IKKβ reverse the immunosuppressive, tumor-supporting state of TAMs and reprogram them to a phenotype that induces anti-tumor immunity and promotes tumor regression. We further establish that these nanoreagents are safe for repeated dosing. Implemented in the clinic, this immunotherapy could enable physicians to obviate suppressive tumors while avoiding systemic treatments that disrupt immune homeostasis.

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Engineering chimeric antigen receptors (CAR) or T cell receptors (TCR) helps create disease-specific T cells for targeted therapy, but the cost and rigor associated with manufacturing engineered T cells ex vivo can be prohibitive, so programing T cells in vivo may be a viable alternative. Here we report an injectable nanocarrier that delivers in vitro-transcribed (IVT) CAR or TCR mRNA for transiently reprograming of circulating T cells to recognize disease-relevant antigens. In mouse models of human leukemia, prostate cancer and hepatitis B-induced hepatocellular carcinoma, repeated infusions of these polymer nanocarriers induce sufficient host T cells expressing tumor-specific CARs or virus-specific TCRs to cause disease regression at levels similar to bolus infusions of ex vivo engineered lymphocytes. Given their ease of manufacturing, distribution and administration, these nanocarriers, and the associated platforms, could become a therapeutic for a wide range of diseases.