Abnormal accumulation of hyaluronan matrix diminishes contact inhibition of cell growth and promotes cell migration.
Elevated hyaluronan biosynthesis and matrix deposition correlates with cell proliferation and migration. We ectopically expressed three isoforms of hyaluronan synthase (HAS1, HAS2, or HAS3) in nontransformed rat 3Y1 cells and observed a de novo, massive formation of a hyaluronan matrix that resulted in a partial loss of contact-mediated inhibition of cell growth and migration. All three HAS transfectants showed an enhanced motility in scratch wound assays, and a significant increase in their confluent cell densities. In high-density cultures, the HAS transfectants had a fibroblastic cell shape and markedly formed overlapping cell layers. This phenotype was more pronounced in the HAS2 transfectants than HAS1 or HAS3 transfectants, and occurred with significant alterations in the microfilament organization and N-cadherin distribution at the cell-cell border. Inhibition of a phosphatidylinositol 3-kinase (PI3-kinase) pathway resulted in reacquisition of the normal phenotype of HAS2 transfectants, suggesting that the intracellular PI3-kinase signaling regulates diminution of contact inhibition induced by formation of the massive hyaluronan matrix. Our observations suggest that hyaluronan and its matrix can modulate contact inhibition of cell growth and migration, and provide evidence for functional differences between hyaluronan synthesized by the different HAS proteins.
Itano
Naoki
N
Institute for Molecular Science of Medicine, Aichi Medical University, Nagakute, Aichi 480-1195, Japan. itano@amugw.aichi-med-u.ac.jp
Atsumi
Fukiko
F
Sawai
Takahiro
T
Yamada
Yoichi
Y
Miyaishi
Osamu
O
Senga
Takeshi
T
Hamaguchi
Michinari
M
Kimata
Koji
K
D000362:Agar; D000818:Animals; D002452:Cell Count; D002455:Cell Division; D002460:Cell Line; D002465:Cell Movement; D048429:Cell Size; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D003260:Contact Inhibition; D003599:Cytoskeleton / Q000378:metabolism; D004912:Erythrocytes; D005109:Extracellular Matrix / Q000201:enzymology / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D005434:Flow Cytometry; D015870:Gene Expression; D014453:Glucuronosyltransferase / Q000235:genetics / Q000378:metabolism; D016695:Glycosyltransferases; D000076002:Hyaluronan Synthases; D006820:Hyaluronic Acid / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins; D008854:Microscopy, Electron; D010641:Phenotype; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051381:Rats; D012756:Sheep; D014162:Transfection; D014166:Transferases; D014945:Wound Healing; D029867:Xenopus Proteins
D007527:Isoenzymes; D008565:Membrane Proteins; D029867:Xenopus Proteins; D000362:Agar; D006820:Hyaluronic Acid; D014166:Transferases; D016695:Glycosyltransferases; D014453:Glucuronosyltransferase; C056944:HAS1 protein, Xenopus; D000076002:Hyaluronan Synthases; D019869:Phosphatidylinositol 3-Kinases