Lymphotropic Virotherapy Engages High Endothelial Venule and Dendritic Cell Inflammation in Tumor Draining Lymph Nodes to Mediate Cancer In Situ Vaccination.

Abstract

We developed PVSRIPO, a highly attenuated, non-cytopathogenic rhino:poliovirus chimera for cancer immunotherapy. Poliovirus (PV) naturally targets CD155+ antigen presenting cells in its only host (humans); its main replication reservoir is the lymphatic system. Wild type (wt) PV is highly cytopathogenic in myeloid cells/lymphoid organs. In contrast, non-cytopathogenic PVSRIPO infection produces extended viral (v)RNA replication yielding cytoplasmic duplex vRNA, engages type-I interferon dominant innate signaling cascades, induces dendritic cell (DC) trafficking to tumor draining lymph nodes (tdLN), and stimulates tumor antigen cross-presentation. This cumulates in polyfunctional antitumor CD8+T cell responses. This project elucidates the importance of tdLN in initiating antitumor immunity and introduces innovative designs to improve tumor immune surveillance by adding PVSRIPO cutaneous perilymphatic injections (CPLI) to directly target tdLN. After intratumor inoculation in subcutaneous and intracerebral tumor models, PVSRIPO accumulates in inguinal or cervical tdLN, respectively, likely due to increased trafficking of PVSRIPO-infected DCs to tdLN. There is overwhelming evidence for endogenous type-I IFN release in DCs to control tumor immune surveillance; hence, PVSRIPO’s type-I IFN dominant innate signature in DCs migrating to/resident in tdLNs may be pivotal for its ability to induce antitumor immunity. Accordingly, blocking IFNa/b receptor signaling in tdLN antagonized the antitumor effect in mice. Our studies indicate that waning type-I IFN release in tdLN early after intratumor administration of PVSRIPO can be rescued, and in fact reversed, by CPLI of virus. We show that DCs are preferentially infected in cervical tdLN after both intratumor injection or CPLI by RNA Flow-FISH and HCR-FISH vRNA costained with CD11c and MECA-79 on HEVs. We hypothesize that combination of intratumor administration and CPLI of PVSRIPO could have a synergistic effect on the tdLN. RNAseq analyses of tdLN from mice treated with intratumor+CPLI of PVSRIPO showed drastic differences in the quality of the transcriptional response compared to mock treatment, or treatment with intratumor or CPLI of PVSRIPO alone. “Dual-site” targeting elevated the frequency of vRNA expression in tdLN, significantly enhanced type-I and -II IFN signaling, and significantly elevated transcriptional signatures associated with genes involved in antigen cross-presentation. Based on our analyses, we hypothesize that dual-site targeting of tdLN with PVSRIPO generates an environment favorable for cross-presentation of tumor antigens in tdLN, the site where antitumor CD8+T cell immunity is primed. Further investigation reveals PVSRIPO vRNA replicates in CD11c+ cells and high endothelial venules (HEVs) after IT and CPLI administration in hCD155-tg mice. Finally, dual-site treatment had significant antitumor and survival benefits in a highly aggressive murine malignant glioma model. A phase II clinical protocol combining tandem repeat intracerebral infusion with iterative CPLI of PVSRIPO just begun accruing patients with recurrent glioblastoma (NCT06177964). Prior to the initiation of the now ongoing phase II trial, three patients with recurrent glioblastoma were treated per the protocol under separate expanded access INDs and IRB approved protocols, demonstrating that CPLI of PVSRIPO is feasible in patients with glioma, and engages T cell activation and effector function in humans.