Oncolytic Vaccinia Virus Expressing HSP70 shRNA Exerts Anti-Tumor Effects in Human Ovarian Cancer via Triggering the Autophagy–ROS Feedback Loop and Immune Activation

Heat shock protein 70 (HSP70) represents a promising target for cancer therapy. Oncolytic vaccinia virus (oncoVV) mediates tumor regression through direct oncolysis and immune activation. However, the anti-tumor potential of HSP70-silenced oncoVV (oncoVV-shHSP70) remains unexplored. Here, we demonstrate that oncoVV-shHSP70 achieves superior tumor regression in ovarian cancer models (cell lines, immunodeficient mice and humanized mice) via dual mechanisms including enhancing apoptosis, autophagy flux, ROS generation, and immune reprogramming. Notably, we found that oncoVV-shHSP70 triggers an autophagy-ROS feedback loop that amplifies viral replication and pro-inflammatory cytokine expression. Crucially, in humanized mice, oncoVV-shHSP70 induced spatial redistribution of cytotoxic T cells, expanding tumor-infiltrating hCD8⁺hGZMB⁺ populations. These findings position oncoVV-shHSP70 as a promising viro-immunotherapy that co-opts HSP70 silencing to potentiate both direct oncolysis and anti-tumor immunity, providing a preclinical rationale for viro-immunotherapy in solid tumors.