Cell Signaling and Cancer Therapy

Biography

Biography: Yuru Liu

Abstract

The alveolar epithelium is composed of type I cells covering most of the gas-blood exchange surface and type II cells secreting surfactant that lowers surface tension of alveoli to prevent alveolar collapse. Here we have identified a subgroup of type II cells expressing higher level of cell surface molecule CD44 (CD44^high type II cells) that comprised ~3% of total type II cells in 5-10 week old mice. These cells were preferentially apposed to lung capillaries. They displayed a higher proliferation rate and augmented differentiation capacity into type I cells and the ability to form alveolar organoids compared to CD44^low type II cells. Moreover, in aged mice of 18-24 months old, the percentage of CD44^high type II cells among all type II cells was increased but these cells showed decreased progenitor properties. Thus, CD44^high type II cells likely represent a type II cell sub-population important for constitutive regulation of alveolar homeostasis. Since CD44 is considered as a marker for cancer stem cells in lung cancer, it is important to further characterize the signaling of CD44^high type II cells in lung homeostasis, regeneration and aging, as disregulation of the CD44^high type II cells is likely to contribute to the cancer initiation.