The role of survivin for radiation therapy. Prognostic and predictive factor and therapeutic target.
Survivin, the smallest member of the inhibitor of apoptosis protein (IAP) family, is a bifunctional protein that has been implicated in both control of cell division and inhibition of apoptosis. This review specially focuses on clinical and experimental data on the relevance of survivin in radiooncology and its role as a therapeutic target to radiosensitize tumor cells. As compared to normal tissue, survivin is overexpressed in tumors and appears to be closely related to tumor malignancy and treatment response. In addition, survivin is involved in the resistance of tumor cells to both chemotherapy and ionising irradiation. Due to these properties, survivin has been proposed as an attractive target for anticancer therapies. Several preclinical studies have demonstrated that suppression of survivin, by the use of antisense oligonucleotides, small interfering RNAs, ribozymes and the application of dominant negative mutants, increases apoptosis, diminishes tumor cell survival and reduces tumor growth potential. Survivin displays a relevant prognostic and predictive factor as well as a promising molecular target to improve the effectiveness of radiotherapy.