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.

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.

We demonstrated that protein corona can be altered by lipid nanoparticle composition changes. Protein corona composition differences had a profound impact on cell transfection, in vivo biodistribution and tumor-specific delivery.

Objective: The purpose of these studies was to develop and characterize B-cell Maturation Antigen (BCMA)-specific peptide encapsulated nanoparticle formulations to efficiently evoke BCMA-specific CD8 + cytotoxic T lymphocytes (CTL) with poly-functional immune activities against multiple myeloma (MM). Findings: Heteroclitic BCMA 72-80 [YLMFLLRKI] peptide encapsulated liposome or poly(lactic-co-glycolic acid) (PLGA) nanoparticles displayed uniform size distribution and increased peptide delivery to human dendritic cells which enhanced induction of BCMA-specific CTL. Distinct from liposome-based nanoparticles, PLGA-based nanoparticles demonstrated a gradual increase in peptide uptake by antigen-presenting cells, and induced BCMA-specific CTL with higher anti-tumor activities (CD107a degranulation, CTL proliferation, and IFN-γ/IL-2/TNFα production) against primary CD138 + tumor cells and MM cell lines. The improved functional activities were associated with increased Tetramer + /CD45RO + memory CTL, CD28 upregulation on Tetramer + CTL, and longer maintenance of central memory (CCR7 + CD45RO +) CTL, with the highest anti-MM activity and less differentiation into effector memory (CCR7 − CD45RO +) CTL. Conclusion: These results provide the framework for therapeutic application of PLGA-based BCMA peptide delivery system, rather than free peptide, to enhance the induction of BCMAspecific CTL with poly-functional Th1-specific anti-MM activities.

Gene therapy makes it possible to engineer chimeric antigen receptors (CARs) to create T cells that target specific diseases. However, current approaches require elaborate and expensive protocols to manufacture engineered T cells ex vivo, putting this therapy beyond the reach of many patients who might benefit. A solution could be to program T cells in vivo. Here, we evaluate the clinical need for in situ CAR T cell programming, compare competing technologies, review current progress, and provide a perspective on the long-term impact of this emerging and rapidly flourishing biotechnology field. Expected final online publication date for the Annual Review of Biomedical Engineering, Volume 23 is June 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.