Signal conversion as tumor micro environment (TME) specifically activated cytokine

Targeted cytokine delivery has been gaining popularity in cancer immunotherapy since systemic recombinant cytokine treatment has not been successful due to low response rate and systemic toxicities in the clinical studies. In order to address these issues, we propose a new concept that cytokine signal is specifically activated at tumor-micro-environment (TME) by delivering two protein subunits of heterodimeric cytokine fused with a tumor targeting antibody respectively to TME and by bridging the two subunits into active heterodimeric form.Interleukin-12 (IL-12) is one of the major cytokines which can induce immune activation. IL-12 consists of two protein subunits which are p35 and p40. IL-12 signaling is initiated when it forms as the heterodimeric protein and binds to IL-12 receptor complex. We made fusion proteins of both IL-12p35 and IL-12p40 targeting specific tumor associated antigens (TAAs) and demonstrated the formation of bioactive IL12p70 with TME targeting antibody toward both p35 and p40 to form as the active molecule. We describe our concept validation in an in vitro based functional assay.

Nanoparticle mediated cancer immunotherapy

The versatility and nanoscale size have helped nanoparticles (NPs) improve the efficacy of conventional cancer immunotherapy and opened up exciting approaches to combat cancer. This review first outlines the tumor immune evasion and the defensive tumor microenvironment (TME) that hinders the activity of host immune system against tumor. Then, a detailed description on how the NP based strategies have helped improve the efficacy of conventional cancer vaccines and overcome the obstacles led by TME. Sustained and controlled drug delivery, enhanced cross presentation by immune cells, co-encapsulation of adjuvants, inhibition of immune checkpoints and intrinsic adjuvant like properties have aided NPs to improve the therapeutic efficacy of cancer vaccines. Also, NPs have been efficient modulators of TME. In this context, NPs facilitate better penetration of the chemotherapeutic drug by dissolution of the inhibitory meshwork formed by tumor associated cells, blood vessels, soluble mediators and extra cellular matrix in TME. NPs achieve this by suppression, modulation, or reprogramming of the immune cells and other mediators localised in TME. This review further summarizes the applications of NPs used to enhance the efficacy of cancer vaccines and modulate the TME to improve cancer immunotherapy. Finally, the hurdles faced in commercialization and translation to clinic have been discussed and intriguingly, NPs owe great potential to emerge as clinical formulations for cancer immunotherapy in near future.