Qin, S. S. | Search bioRxiv

bioRxiv2023

Local Delivery of SBRT and IL12 by mRNA Technology Overcomes Immunosuppressive Barriers to Eliminate Pancreatic Cancer

The immunosuppressive milieu in pancreatic cancer (PC) is a significant hurdle to treatments, resulting in survival statistics that have barely changed in 5 decades. Here we present a combination treatment consisting of stereotactic body radiation therapy (SBRT) and IL-12 mRNA lipid nanoparticles delivered directly to pancreatic murine tumors. This treatment was effective against primary and metastatic models, achieving cures in both settings. IL-12 protein concentrations were transient and localized primarily to the tumor. Depleting CD4 and CD8 T cells abrogated treatment efficacy, confirming they were essential to treatment response. Single cell RNA sequencing from SBRT/IL-12 mRNA treated tumors demonstrated not only a complete loss of T cell exhaustion, but also an abundance of highly proliferative and effector T cell subtypes. SBRT elicited T cell receptor clonal expansion, whereas IL-12 licensed these cells with effector function. This is the first report demonstrating the utility of SBRT and IL-12 mRNA in PC. Statement of significanceThis study demonstrates the use of a novel combination treatment consisting of radiation and immunotherapy in murine pancreatic tumors. This treatment could effectively treat local and metastatic disease, suggesting it may have the potential to treat a cancer that has not seen a meaningful increase in survival in 5 decades.

cancer biology↗

bioRxiv2020

Intertumoral Genetic Heterogeneity Generates Distinct Tumor Microenvironments in a Novel Murine Synchronous Melanoma Model

Synchronous metastatic melanoma, clinically defined as multiple lesions diagnosed within 6 months, has a poor prognosis. Despite recent advances in systemic immunotherapy, a majority of patients fail to respond or exhibit lesion-specific responses. While intertumoral heterogeneity has been clinically associated with lesion-specific therapeutic responses, no clear mechanism has been identified, largely due to the scarcity of preclinical models. We developed a novel murine synchronous melanoma model that recapitulates clinical intertumoral heterogeneity. We show that genetic differences between tumors generate distinct tumor immune microenvironments (TIME). These TIMEs can independently upregulate PD-1/PD-L1 expression in response to ongoing anti-tumor immunity and the presence of interferon-gamma. The simultaneous presence of multiple tumors can additionally alter the TIME of each tumor. As such, our model provides a unique approach to investigate the effects of intertumoral heterogeneity on mechanisms of immunotherapy resistance.

cancer biology↗