Matrilin-2 regulates proliferation, apoptosis and cell cycle during radiation-induced injury in HPAEpiC cell.

Radiation pulmonary injury is related to the accumulation of extracellular matrix proteins in the alveolar interstitial space. Matrilin-2 as a component of extracellular filamentous networks, present higher level in the lung tissue from irradiated mice and irradiated pulmonary epithelial cell line, HPAEpiC cells. Knockdown of endogenous matrilin-2 prevents the apoptosis of HPAEpiC cell induced by the irradiation injury. Consistently, over-expression of matrilin-2 reduced the proliferation and induced apoptosis of HPAEpiC cells. Matrilin-2 promotes the expression of p21 via increasing the transcriptional activity of p53, by which induces the G1 phase arresting in HPAEpiC cells. In summary, matrilin-2, increased by irradiation, reduced the proliferation and induces apoptosis of pulmonary epithelial cells via p53/p21 pathway.