Rewiring oncogenic signaling to RNA vector replication for the treatment of metastatic cancer.

Despite recent advances, improvements to long-term survival in metastatic carcinomas, such as pancreatic or ovarian cancer, remain limited. Current therapies suppress growth-promoting biochemical signals, ablate cells expressing tumor-associated antigens, or promote adaptive immunity to tumor neoantigens. However, these approaches are limited by toxicity to normal cells using the same signaling pathways or expressing the same antigens, or by the low frequency of neoantigens in most carcinomas. Here, we report a fundamentally different strategy for designing safer and more effective anti-cancer therapies through the sensing of cancer-driving biochemical signals and their rewiring to virotherapeutic activation. Specifically, we rationally engineer a RNA vector to self-replicate and cause cytotoxicity in cancer cells exhibiting hyperactive HER2 (ErbB2), but not in normal cells with normal HER2 signaling. Compared to a widely tested virotherapeutic from the same vector family, our hyperactive ErbB2-restricted RNA vector (HERV) exhibits lower toxicity and greater activity against metastatic HER2-positive ovarian cancer in mice, extending survival independently of tumor antigenicity. Most importantly, HERV synergizes with standard-of-care chemotherapy against ovarian cancer metastases in vivo, with 43% of combination-treated subjects surviving for months beyond subjects treated with either therapy alone. Taken together, these results introduce rewiring of cancer-driving signaling pathways to virotherapeutic activation as a strategy for more specific and effective cancer treatment.