Sirtuins, tissue maintenance, and tumorigenesis.

Aging is a degenerative process resulting in compromised tissue maintenance and increased susceptibility to diseases, such as cancer. Recent advancements support the notion that aging is a highly regulated process governed by evolutionarily conserved pathways. In mammals, tissue-specific adult stem cells (ASCs) persist throughout the lifetime to maintain and repair tissues. While reduced ASC self-renewal is thought to contribute to compromised tissue maintenance, increased self-renewal of cancer stem cells (CSCs) may lead to tumorigenesis. It is speculated that genetic regulators of aging, such as sirtuins, are likely to impinge upon the ASC compartments to regulate tissue maintenance and tumorigenesis. In this review, we discuss the emerging evidence linking sirtuins to normal and malignant ASC self-renewal, tissue maintenance, and tumorigenesis.