Identification of the region in calponin h1 that suppresses proliferation and motility of human fibrosarcoma

点击翻译按钮获取中文摘要

To investigate the effects of calponin h1(CNh1) on the cell proliferation and motility, human calponin h1 was transfected to human fibrosarcoma, HT1080. CNh1-transfected cells exhibited flattened morphology with organized actin filaments, significant decrease in cell motility. Anchorage-independent growth and tumorigenicity in nude mice were suppressed in CNh1-transfected cells.To identify the region of CNh1 that suppresses proliferation and motility, CNh1 consisted of four domains, CHD, actin binding site (ABS), CNrepeats (CNR) and C terminal, were divided to 12 truncates. As a result, the motility was suppressed by the CNR. Since Repeat 1 (R1) of CNR is reported as a second actin binding site, and has targets of protein kinase C (PKC), actin-depolymerization and podosome formation was investigated. Actin-depolymerization was suppressed by the stimulation with cytochalasin D, and formation of podosome was also suppressed with PDBu (PKC stimulator) in CNh1 transfected cells. Truncates that lack ABS or CNR-R1, and mutant that has mutation of S175A and T184A were transfected. In all three transfectants, transverse actin fiber was separated from calponin h1 and podosome formation was facilitated. Calponin h1 is considered to resist cytochalasin D or PDBu by binding to transverse actin fiber in tumor cells.