Role of Oncoviruses in Cancer Progression and Emerging Phytochemical-Based Therapies from Medicinal Plants

Oncoviruses continues to be an unattended cause of the global cancer load as they cause about 12-15 % of human malignancies in the world. The oncogenic infections that become persistent, such as Human Papillomavirus (HPV), Epstein-Barr Virus (EBV), Hepatitis B and C viruses (HBV, HCV), Human T cell Leukemia Virus-1 (HTLV-1), and Kaposi Sarcoma-associated Herpesvirus (KSHV), are associated with malignant transformation by continuous destabilization of host cell cycle regulation, immune surveillance, and metabolic homeostasis. These viruses abuse critical oncogenic signaling networks like PI3K/AKT/mTOR, NF -KB, JAK/STAT, MAPK, Wnt/β-catenin, and p53-dependent networks, hence, facilitating unchecked proliferation, chronic inflammation, genomic instability, and tumor progression. Although there have been improvements in the traditional forms of treatment, such as chemotherapy, radiotherapy, antiviral agents, immunotherapy, and gene-based treatments, yet clinical outcomes are still hampered by drug resistance, viral latency, systemic toxicity, and inaccessibility, and other severe side effects especially in low- and middle-income nations. Hence, there is a dire need to introduce new medicinal plant-based therapeutic approaches against oncovirus. This review analyses the molecular pathways of viral oncogenesis critically and discusses the clinical translation and a promising future potential of phytochemicals derived from medicinal plants like Phyllanthus emblica, Datura stramonium, Cannabis sativa, Andrographis paniculata, Aegle marmelos, Calotropis procera, and Prosopis cineraria proven to have bioactive compounds functioning as antivirals, immune-modulator, pro-apoptotic, and cell cycle regulatory effects in the preclinical models along with multi-targets.