Tumor cell machinery supporting HSV-1 oncolytic replication

Tumor cell machinery supporting HSV-1 oncolytic replication refers to the collective host cell factors and dysregulated pathways that allow oncolytic Herpes Simplex Virus type 1 (oHSV-1) to selectively infect, replicate within, and destroy malignant cells. This machinery includes high-affinity entry receptors such as Nectin-1 (PVRL1) and Herpesvirus Entry Mediator (HVEM), which are often overexpressed on the surface of cancer cells (Campadelli-Fiume et al., 2007). A critical aspect of this machinery is the impaired antiviral response in tumors, specifically the Protein Kinase R (PKR) pathway. While healthy cells use PKR to halt protein synthesis upon viral detection, many tumors lack this defense or overexpress GADD34, which dephosphorylates eIF2α to maintain translation (He et al., 1997). Engineered oHSV-1 strains, such as Talimogene laherparepvec (T-VEC), are designed to exploit these vulnerabilities by deleting viral genes like γ34.5, rendering them dependent on the tumor's aberrant machinery for survival (Reid et al., 2016). This selectivity ensures that viral replication and subsequent oncolysis are restricted to the tumor microenvironment, minimizing damage to healthy tissues. The process ultimately promotes immunogenic cell death, which stimulates a systemic anti-tumor immune response (Liu et al., 2003). Understanding these cellular components is essential for identifying biomarkers of response and developing next-generation oncolytic vectors. Therapeutic challenges include the presence of neutralizing antibodies and the physical barriers within the tumor stroma that limit viral spread (Todo et al., 2001). Overall, this machinery represents a complex interface between viral biology and cancer pathophysiology used in modern immunotherapy.

Other names

oHSV-1 host factorsOncolytic HSV-1 replication machineryTumor-selective viral entry and replication factors

Exploitation of tumor-specific entry receptors and defective host antiviral pathways (e.g., PKR/eIF2α) to achieve selective viral propagation and immunogenic cell death.