Cellular redox, cancer and human papillomavirus

Human Papillomavirus (HR-HPV) is the causative agent of different human cancers. A persistent HR-HPV infection alters several cellular processes involved in cell proliferation, apoptosis, immune evasion, genomic instability and transformation. Cumulative evidence from past studies indicates that HR-HPV proteins are associated with oxidative stress (OS) and has been proposed as a risk factor for cancer development. Reactive oxygen and nitrogen species (RONS) regulate a plethora of processes inducing cellular proliferation, differentiation and death. Oxidative stress (OS) is generated when an imbalance in the redox state occurs due to deregulation of the oxidant and antioxidant systems, which, in turn, promotes the damage of DNA, proteins and lipids, allowing the accumulation of mutations and genome instability. OS has been associated with the establishment and development of different cancers, and it has recently been proposed as a co-factor in cervical cancer development. This review is focused on evidence regarding the association of OS with HR-HPV proteins, and the interplay of the viral proteins with different elements of the antioxidant and DNA damage response (DDR) systems, emphasizing the processes that might be required for the viral life cycle and viral DNA integration into the host genome, which is a key element in the carcinogenic process induced by HR-HPV.