Survivin

Survivin, also known by its gene name BIRC5 (baculoviral IAP repeat-containing 5), is a protein that belongs to the inhibitor of apoptosis (IAP) family. It plays a critical role in cell cycle regulation and inhibition of programmed cell death (apoptosis). Survivin is primarily expressed during fetal development and in some adult tissues, particularly those with high proliferative activity, such as the thymus and certain stem cell populations.

In cancer, survivin is frequently overexpressed, contributing to tumor growth and resistance to therapy by promoting cell survival and division. Its elevated levels are associated with poor prognosis in various cancers, including breast, lung, and colorectal cancers. The protein functions by inhibiting caspases, which are essential mediators of apoptosis, and by regulating cell division through its role in the chromosomal passenger complex.

Survivin's expression is tightly regulated during the cell cycle, with peak levels observed during the G2/M phase, aligning with its role in mitosis. Due to its selective expression in cancer cells and low presence in most normal differentiated tissues, survivin has garnered interest as a potential target for anticancer therapies.

Research efforts have focused on developing survivin inhibitors, such as small molecules, antisense oligonucleotides, and immunotherapies, aiming to enhance the efficacy of existing treatments by sensitizing cancer cells to apoptosis. Despite ongoing investigations, survivin-targeted therapies are still under clinical evaluation and are not yet standard treatment options.

Overall, survivin's dual function in cell division and apoptosis inhibition underscores its importance in cellular biology and its potential as a therapeutic target in oncology.