Durable anticancer immunity from intratumoral administration of IL-23, IL-36γ, and OX40L mRNAs.

Many solid cancers contain dysfunctional immune microenvironments. Immune system modulators that initiate responses to foreign pathogens could be promising candidates for reigniting productive responses toward tumors. Interleukin-1 (IL-1) and IL-12 cytokine family members cooperate at barrier tissues after microbial invasion, in human inflammatory diseases, and in antitumoral immunity. IL-36γ, in classic alarmin fashion, acts in damaged tissues, whereas IL-23 centrally coordinates immune responses to danger signals. In this study, direct intratumoral delivery of messenger RNAs (mRNAs) encoding these cytokines produced robust anticancer responses in a broad range of tumor microenvironments. The addition of mRNA encoding the T cell costimulator OX40L increased complete response rates in treated and untreated distal tumors compared to the cytokine mRNAs alone. Mice exhibiting complete responses were subsequently protected from tumor rechallenge. Treatments with these mRNA mixtures induced downstream cytokine and chemokine expression, and also activated multiple dendritic cell (DC) and T cell types. Consistent with this, efficacy was dependent on Batf3-dependent cross-presenting DCs and cytotoxic CD8+ T cells. IL-23/IL-36γ/OX40L triplet mRNA mixture triggered substantial immune cell recruitment into tumors, enabling effective tumor destruction irrespective of previous tumoral immune infiltrates. Last, combining triplet mRNA with checkpoint blockade led to efficacy in models otherwise resistant to systemic immune checkpoint inhibition. Human cell studies showed similar cytokine responses to the individual components of this mRNA mixture, suggesting translatability of immunomodulatory activity to human patients.

Enhanced transduction of colonic cell lines in vitro and the inflamed colon in mice by viral vectors, derived from adeno-associated virus serotype 2, using virus-microbead conjugates bearing lectin.

BACKGROUND: Virus-mediated delivery of therapeutic transgenes to the inflamed colon holds a great potential to serve as an effective therapeutic strategy for inflammatory bowel disease, since local, long-term expression of the encoded therapeutic proteins in the colorectal system is potentially achievable. Viral vectors, derived from adeno-associated virus (AAV), should be very useful for such therapeutic strategies, particularly because they can establish long-term expression of transgenes. However, few studies have been carried out to investigate the ability of AAV-based vectors to transduce the inflamed colon. RESULTS: AAV, derived from adeno-associated virus serotype 2 (AAV2), showed a limited ability to transduce colonic cell lines in vitro when used in free form. No appreciable enhancement of the transduction efficiency was seen when AAV2 particles were attached stably to the surfaces of microbeads and delivered to target cells in the form of AAV2-microbead conjugates. However, the transduction efficiency of these colonic cell lines was enhanced substantially when a lectin, concanavalin A (Con A), was co-attached to the microbead surfaces, to which AAV2 particles had been conjugated. This considerable infectivity enhancement of AAV2-microbead conjugates by the co-attachment of Con A may be derived from the fact that Con A binds to alpha-D-mannosyl moieties that are commonly and abundantly present in cell-surface carbohydrate chains, allowing the conjugates to associate stably with target cells. Intracolonical administration of free AAV2 or AAV2-microbead conjugates without Con A into a mouse colitis model by enema showed very poor transduction of the colonic tissue. In contrast, the delivery of AAV2 in the form of AAV2-microbead conjugates bearing Con A resulted in efficient transduction of the inflamed colon. CONCLUSION: AAV2-microbead conjugates bearing Con A can serve as efficient gene transfer agents both for poorly permissive colonic cell lines in vitro and for the inflamed colon in a mouse colitis model. This efficient transduction system for the inflamed colon should be useful for the development of gene therapy strategies for inflammatory bowel disease.

A chimera of a gelatinase inhibitor peptide with streptavidin as a bifunctional tumor targeting reagent.

A chimeric protein, consisting of streptavidin fused to a cyclic decapeptide with potent inhibitory activity for matrix metalloproteinases (MMP), has been produced in Escherichia coli and purified. The purified chimera formed a tetramer and showed full biotin-binding ability. The chimera was also capable of both binding to MMP-2 and inhibiting its activity. Thus, both the streptavidin moiety and the decapeptide of the chimera are fully functional. This bifunctional nature of the chimera should facilitate the application of the decapeptide since the streptavidin moiety can be used as a specific conjugation site for almost any materials upon biotinylation.