Enhanced expression of lumican inhibited the attachment and growth of human embryonic kidney 293 cells.
Lumican is a member of a small leucine-rich proteoglycan (SLRP) family and it regulates the assembly and diameter of collagen fibers in the extracellular matrix of various tissues. Lumican expression was reported in various kinds of tumor cells. Lumican inhibits the growth of melanoma cells, but the lumican in pancreatic cancer correlated with an advanced stage and retroperitoneal and duodenal invasion. In this study, we clarified whether the enhanced expression of lumican contributes to cellular attachment, growth, colony formation, migration and invasion. HEK 293 cell, stably transfected with lumican cDNA synthesized and secreted a 50 kDa lumican protein at high levels in culture medium. The cells showed a polygonal appearance with long projections and the degree of adhesion of the cells to fibronectin was lower than that of empty vector transfected control cells (mock cells). In contrast, the degree of adhesion of the cells to type I collagen was not different from that of mock cells. The expression levels of alpha5 integrin, the major integrin subunit for fibronectin, were lower in lumican-transfected HEK cells than in mock cells. Furthermore, lumican-transfected HEK cells showed reduced growth rates in vitro and did not form colonies in soft agar. Phosphorylation of AKT, extracellular signal-regulated kinase (ERK) 1/2 and mammalian target of rapamycin (mTOR) decreased in the lumican-transfected HEK cells. Cell migration and invasion were not altered in lumican-transfected HEK cells and mock cells. These findings indicate that the 50kDa lumican protein plays important roles in the inhibition of HEK cell attachment and growth, and it might inhibit the activation of integrin pathways.
Department of Pathology, Integrative Oncological Pathology, Nippon Medical School, Tokyo, Japan. ishiwata@nms.ac.jp
Toshiyuki
T
Ishiwata
Tetsushi
T
Yamamoto
Kiyoko
K
Kawahara
Yoko
Y
Kawamoto
Yoko
Y
Matsuda
Shunji
S
Ishiwata
Zenya
Z
Naito
D001483:Base Sequence; D002448:Cell Adhesion / Q000235:genetics / Q000502:physiology; D002460:Cell Line; D002465:Cell Movement / Q000235:genetics / Q000502:physiology; D049109:Cell Proliferation; D011508:Chondroitin Sulfate Proteoglycans / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D024042:Collagen Type I / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D005353:Fibronectins / Q000378:metabolism; D015870:Gene Expression; D006031:Glycosylation; D006801:Humans; D016023:Integrins / Q000378:metabolism; D007632:Keratan Sulfate / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D007668:Kidney / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D000071234:Lumican; D020935:MAP Kinase Signaling System; D008970:Molecular Weight; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection
D011508:Chondroitin Sulfate Proteoglycans; D024042:Collagen Type I; D017931:DNA Primers; D005353:Fibronectins; D016023:Integrins; C000604306:LUM protein, human; D000071234:Lumican; D012333:RNA, Messenger; D011994:Recombinant Proteins; D007632:Keratan Sulfate