Mitochondria and chronic effects of cancer therapeutics: The clinical implications.

One of the major mechanisms of action of chemo-radiation is to induce cellular senescence, which exerts crucial roles in age-related pathology. The concept of senescence is evolved, and the novel understanding of senescence-associated reprogramming/stemness has emerged. This new concept emphasizes senescence as not only cell cycle arrest but describes that subsets of senescent cells induced by chemotherapy can re-enter cell cycles, proliferate rapidly, and acquire "stemness" status. Cancer therapeutics, including chemo-radiation triggers toxicity effects through damaging mitochondria, primarily through the upregulation of mtROS production leading to subsequent mtDNA and telomeric DNA damage elicitng DNA damage responses (DDR). The ultimate goal of this review is to highlight the new concept of senescence-associated stemness that is induced by cancer treatment and its adverse effects on the vascular system. We will describe how chemo-radiation exerts toxicity effects by simultaneously producing reactive oxygen species in mitochondria and promoting DDR in the nucleus. We discuss the potential of clinical targeting poly (ADP-ribose) polymerase which might prevent downstream mitochondrial dysfunction and confer protection to cancer survivors. Overall we emphasize the importance of recognizing the consequences of cardio-toxic effects of several cancer treatments and therefore developing personalized therapeutic approaches to screen for inflammatory and cardiac testing for better patient survival.