Redox-responsive interleukin-2 nanogel specifically and safely promotes the proliferation and memory precursor differentiation of tumor-reactive T-cells

Interleukin-2 (IL-2) is a potent T-cell mitogen that can adjuvant anti-cancer adoptive T-cell transfer (ACT) immunotherapy by promoting T-cell engraftment. However, the clinical applications of IL-2 in combination with ACT are greatly hindered by the severe adverse effects such as vascular leak syndrome (VLS). Here, we developed a synthetic delivery strategy for IL-2 via backpacking redox-responsive IL-2/Fc nanogels (NGs) to the plasma membrane of adoptively transferred T-cells. The NGs prepared by traceless chemical cross-linking of cytokine proteins selectively released the cargos in response to T-cell receptor activation upon antigen recognition in tumors. We found that IL-2/Fc delivered by T-cell surface-bound NGs expanded transferred tumor-reactive T-cells 80-fold more than the free IL-2/Fc of an equivalent dose administered systemically and showed no effects on tumor-infiltrating regulatory T-cell expansion. Intriguingly, IL-2/Fc NG backpacks that facilitated a sustained and slow release of IL-2/Fc also promoted the CD8(+) memory precursor differentiation and induced less T-cell exhaustion in vitro compared to free IL-2/Fc. The controlled responsive delivery of IL-2/Fc enabled the safe administration of repeated doses of the stimulant cytokine with no overt toxicity and improved efficacy against melanoma metastases in a mice model.

Engineering T Cell Trafficking and Function for Enhanced Cancer Immunotherapy

Yuqing Xie

In the past decades, breakthroughs in cancer immunotherapy have led to unprecedented clinical responses in patients with advanced-stage cancers that would otherwise be fatal. However, treatment of many solid organ malignancies with highly immunosuppressive tumor microenvironment (TME) remains challenging. Tumors develop a number of mechanisms to prevent effector T-cells from reaching tumors and to suppress their function. T-cell infiltration into solid tumor, a key limiting factor for efficacious cancer immunotherapy, has been demonstrated to be associated with good clinical outcomes in various cancer immunotherapies. Safe and effective strategies to improve T-cell infiltration and augment T-cell expansion and function in solid tumors are highly desired to enhance the clinical response rate of cancer immunotherapies in the treatment of solid tumors. Disruption of chemotaxis of lymphocytes is likely a main contributing factor for effector T-cell exclusion; chemokines are known to play a critical role in orchestrating T-cell trafficking and tumor infiltration. Here, we developed a TME-responsive nanogel (NG) based on a novel carrier-free delivery strategy to effectively and specifically co-deliver T-cell recruiting chemokines and immunostimulatory cytokines in order to enhance infiltration and function of effector T-cells in solid tumors. In the preliminary studies, a chemokine (e.g. CCL19) and a cytokine (IL-2) were chemically co-crosslinked with a redox responsive linker to form the binary protein nanogels (BNGs). These BNGs had exceptionally high loading capacity of cytokines and chemokines and controlled size. BNGs released native cytokine/chemokine proteins in response to increased reduction which is one of the biochemical characteristics of TME, and thus enabled tumor-specific delivery of the incorporated cytokines and chemokines. In vitro chemotaxis assays showed that the released chemokines from BNG possessed the similar chemotactic ability in recruiting activated T-cells. Preliminary in vivo study in subcutaneous B16F10 mouse melanoma in C57BL/6 mice showed that intratumorally administration of BNG enhanced T-cell infiltration and improved immunosuppressive TME compared to free cytokines or chemokines at equivalent doses. In future, we first plan to further improve the controlled formulation of chemokine NG by complexing chemokines with anionic polysaccharides and stabilizing chemokines with non-functional proteins/polymers or recombinantly expressing chemokine-Fc fusion. Then, we plan to enhance the potency of NG for T-cell infiltration and function by delivery combinational chemokines and by activating LTÎ²R signaling with LIGHT delivery. Furthermore, to improve the tumor-targeting effect of NG, we will synthesize cross-linkers in response to different characteristics of TME, prolong the half-life of NG for increased tumor targeting and hijack tumor-related immune cells. Finally, we will try to overcome the immunosuppression in TME by combining NG with checkpoint blockade or adoptive T-cell immunotherapies.

EPFL2022

Enhancing Efficacy of Anticancer Vaccines by Targeted Delivery to Tumor-Draining Lymph Nodes

Marie Ballester, Patricia Corthésy Henrioud, Alexandre de Titta, Jeffrey Alan Hubbell, Laura Jeanbart, Pedro Romero, Melody Swartz

The sentinel or tumor-draining lymph node (tdLN) serves as a metastatic niche for many solid tumors and is altered via tumor-derived factors that support tumor progression and metastasis. tdLNs are often removed surgically, and therapeutic vaccines against tumor antigens are typically administered systemically or in non-tumor-associated sites. Although the tdLN is immune-suppressed, it is also antigen experienced through drainage of tumor-associated antigens (TAA), so we asked whether therapeutic vaccines targeting the tdLN would be more or less effective than those targeting the non-tdLN. Using LN-targeting nanoparticle (NP)-conjugate vaccines consisting of TAA-NP and CpG-NP, we compared delivery to the tdLN versus non-tdLN in two different cancer models, E.G7-OVA lymphoma (expressing the nonendogenous TAA ovalbumin) and B16-F10 melanoma. Surprisingly, despite the immune-suppressed state of the tdLN, tdLN-targeting vaccination induced substantially stronger cytotoxic CD8(+) T-cell responses, both locally and systemically, than non-tdLN-targeting vaccination, leading to enhanced tumor regression and host survival. This improved tumor regression correlated with a shift in the tumor-infiltrating leukocyte repertoire toward a less suppressive and more immunogenic balance. Nano-particle coupling of adjuvant and antigen was required for effective tdLN targeting, as nanoparticle coupling dramatically increased the delivery of antigen and adjuvant to LN-resident antigen-presenting cells, thereby increasing therapeutic efficacy. This work highlights the tdLN as a target for cancer immunotherapy and shows how its antigen-experienced but immune-suppressed state can be reprogrammed with a targeted vaccine yielding antitumor immunity. (C) 2014 AACR.

Amer Assoc Cancer Research2014

Nanoparticle Conjugation of Human Papillomavirus 16 E7-long Peptides Enhances Therapeutic Vaccine Efficacy against Solid Tumors in Mice

Gabriele Galliverti, Douglas Hanahan, Sylvie Hauert, Melody Swartz, Mélanie Louise Tichet, Stephan Wullschleger

Treatment of patients bearing human papillomavirus (HPV)-related cancers with synthetic long-peptide (SLP) therapeutic vaccines has shown promising results in clinical trials against premalignant lesions, whereas responses against later stage carcinomas have remained elusive. We show that conjugation of a well-documented HPV-E7 SLP to ultra-small polymeric nanoparticles (NP) enhances the antitumor efficacy of therapeutic vaccination in different mouse models of HPV+ cancers. Immunization of TC-1 tumor-bearing mice with a single dose of NP-conjugated E7LP (NP-E7LP) generated a larger pool of E7-specific CD8(+) T cells with increased effector functions than unconjugated free E7LP. At the tumor site, NP-E7LP prompted a robust infiltration of CD8(+) T cells that was not accompanied by concomitant accumulation of regulatory T cells (Tregs), resulting in a higher CD8(+) T-cell to Treg ratio. Consequently, the amplified immune response elicited by the NP-E7LP formulation led to increased regression of large, well-established tumors, resulting in a significant percentage of complete responses that were not achievable by immunizing with the non-NP-conjugated long-peptide. The partial responses were characterized by distinct phases of regression, stable disease, and relapse to progressive growth, establishing a platform to investigate adaptive resistance mechanisms. The efficacy of NP- E7LP could be further improved by therapeutic activation of the costimulatory receptor 4-1BB. This NP-E7LP formulation illustrates a "solid-phase" antigen delivery strategy that is more effective than a conventional free-peptide ("liquid") vaccine, further highlighting the potential of using such formulations for therapeutic vaccination against solid tumors. (C) 2018 AACR.

AMER ASSOC CANCER RESEARCH2018