alpha2,6-hyposialylation of c-Met abolishes cell motility of ST6Gal-I-knockdown HCT116 cells.
OBJECTIVE
We aimed to investigate the potential modification of previously unrecognized surface glycoprotein(s) by alpha2,6-sialylation other than by integrins.


METHODS
The expression of beta-galactoside alpha2,6-sialyltransferase (ST6Gal-I) in the colon cancer cell line HCT116 was reduced by siRNA. The adhesion and Boyden chamber assay were used to detect the variation in cell motility. alpha2,6-Sialylation proteins were detected with lectin affinity assay. The mRNA expression, protein expression and downstream signaling modulation with siRNA were detected using reverse transcription-polymerase chain reaction, flow cytometry analysis, and Western blot.


RESULTS
In HCT116 cells, the knockdown of ST6Gal-I inhibited cell motility, but did not affect cell adhesion. This selectively altered cell migration was caused by the loss of alpha2,6-sialic acid structures on c-Met. Moreover, STAT3 was dephosphorylated at tyrosine 705 in ST6Gal-I-knockdown (ST6Gal-I-KD) HCT116 cells.


CONCLUSIONS
c-Met is the substrate of ST6Gal-I. The hyposialylation of c-Met can abolish cell motility in ST6Gal-I-KD HCT116 cells.Acta Pharmacologica Sinica (2009) 30: 1039-1045; doi: 10.1038/aps.2009.84; published online 1 June 2009.
Qian
Jin
J
Division of Anti-tumor Pharmacology, Shanghai Institute of Materia Medica, Shanghai 201203, China.
Zhu
Cai-Hua
CH
Tang
Shuai
S
Shen
Ai-Jun
AJ
Ai
Jing
J
Li
Jing
J
Geng
Mei-Yu
MY
Ding
Jian
J
D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement / Q000502:physiology*; D055785:Gene Knockdown Techniques; D045325:HCT116 Cells / Q000502:physiology*; D006801:Humans; D019859:Proto-Oncogene Proteins c-met / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000378:metabolism; D012794:Sialic Acids / Q000737:chemistry / Q000378:metabolism*; D012799:Sialyltransferases / Q000235:genetics / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase
D034741:RNA, Small Interfering; D050796:STAT3 Transcription Factor; D012794:Sialic Acids; D014443:Tyrosine; D012799:Sialyltransferases; D019859:Proto-Oncogene Proteins c-met; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase