Development of a Curative Therapeutic Vaccine (TheraVac) for the Treatment of Large Established Tumors

Abstract

Harnessing immune system to treat cancer requires simultaneous generation of tumor-specific CTLs and curtailment of tumor immunosuppressive environment. Here, we developed an immunotherapeutic regimen capable of eliminating large established mouse tumors using HMGN1, a DC-activating TLR4 agonist capable of inducing anti-tumor immunity. Intratumoral delivery of HMGN1 with low dose of Cytoxan cured mice bearing small (∅ ≈ 0.5 cm), but not large (∅ ≈ 1.0 cm) CT26 tumors. Screening for activators capable of synergizing with HMGN1 in activating DC identified R848. Intratumoral delivery of HMGN1 and R848 plus Cytoxan eradicated large established CT26 tumors. The resultant tumor-free mice were resistant to subsequent challenge with CT26, indicating the generation of CT26-specific protective immunity. This immunotherapeutic regimen caused homing of tumor-infiltrating DC to draining lymph nodes and increased infiltration of T cells into tumor tissues. Cytoxan in this regimen could be replaced by anti-CTLA4) or anti-PD-L1. Importantly, this immunotherapeutic regimen was also curative for large established mouse Renca and EG7 tumors. Thus, we have developed a curative therapeutic vaccination regimen dubbed ‘TheraVac’ consisting of HMGN1 and R848 plus a checkpoint inhibitor, that can, without using exogenous tumor-associated antigen(s), eliminate various large tumors and induce tumor-specific immunity.

Combining Rapid Data Independent Acquisition and CRISPR Gene Deletion for Studying Potential Protein Functions: A Case of HMGN1

“…In agreement with the above BPs, cellular components (CC) such as Extracellular exosome (GO:0070062, p = 4.79E‐04), Integral component of plasma membrane (GO:0005887, p = 0.0050), and Clathrin‐coated vesicle (GO:0030136, p = 0.0022) associated proteins were differentially regulated. Two KEGG pathways, Complement and coagulation cascades ( p = 5.72E‐4) and ECM‐receptor interaction ( p = 0.0343), were also enriched in the 147‐protein list, reinforcing the newly discovered role of HMGN1 in immune response …”

“…reported that extracellular HMGN1 acts as a novel alarmin that binds TLR4 and induces antigen‐specific Th1 immune responses and could be a potent immunoadjuvant by supporting T cell–mediated antitumor immunity . Recently, a curative therapeutic vaccination regimen dubbed “TheraVac” consisting of HMGN1 and resiquimod plus a checkpoint inhibitor was developed with the potential to eliminate various large tumors and induce tumor‐specific immunity . Our proteomic profiling is promising in this regard, because complement and coagulation cascades and interferon alpha or gamma responses were found to be significantly induced upon HMGN1 deletion, and therefore provides additional insights of HMGN1's role in immunity.…”

Alarmin-painted exosomes elicit persistent antitumor immunity in large established tumors in mice

“…Immunoadjuvants, particularly endogenous ones such as HMGN1, likely present fewer nonspecific immunological side effects than exogenous adjuvants such as bacterial lipopolysaccharides. Therefore, HMGN1 has been extensively investigated in combination with other chemotherapeutic agents and activators for other TLR pathways or checkpoint inhibitors [13][14][15] , but the effective delivery of HMGN1 to tumors has confounded researchers. Here we described a simple and effective approach to load the potent N1ND immunoadjuvant on TEXs via an exosomal anchor peptide (TEX-N1ND), resulting in efficient delivery of N1ND to DCs together with TAAs.…”

“…High-mobility group nucleosome-binding protein 1 (HMGN1) improves DC maturation and activation in response to exogenous antigens and consistently induces Th1 immune responses 12 . Hence HMGN1 has been harnessed to promote generation of antitumor immune responses as DNA vaccines or in combination with chemotherapeutic agents and activators/checkpoint inhibitors in different tumor models [13][14][15] . However, only limited effects were achieved with DNA vaccines and combinatorial therapy since HMGN1 required intratumoral administration, which is not clinically applicable to most tumors.…”

“…TEXs, particularly patient-derived TEXs, have good biocompatibility, low immunogenicity, and high penetration of biological barriers, thus TEXs are good activators of DC vaccines. It was previously shown that covalent linkage of an alarmin to a target TAA could better promote TAA-specific immune responses and immunoprotection 13,14 . Ideally, a method that combines delivery of molecular adjuvants with the TAAenriched exosomes would improve the immunogenicity of DC immunotherapy and consequently, potential therapeutic outcome.…”