Involvement of oligosaccharide changes in alpha5beta1 integrin in a cisplatin-resistant human squamous cell carcinoma cell line.
Multiple mechanisms are involved in the resistance of cancer cells to cisplatin, including the expression of multidrug resistance-associated protein (MRP) and enhanced DNA repair. Here, we report findings to show that oligosaccharide changes in alpha5beta1 integrin are associated with cisplatin resistance in a head and neck squamous cell carcinoma cell line, HSC-2. Cisplatin-resistant HSC-2 (HSC-2/CR) cells were established by stepwise treatment with various concentrations of cisplatin. The oligosaccharides containing beta1, 6-N-acetylglucosamine (beta1-6GlcNAc) branching, detected by leukoagglutinating phytohemagglutinin (L(4)-PHA) lectin blot, were found to be dramatically decreased in alpha5beta1 integrin immunoprecipitated from HSC-2/CR cells. To better understand the mechanisms underlying cisplatin resistance and oligosaccharide alteration, we analyzed the downstream signaling of alpha5beta1 integrin, one of the target glycoproteins of beta1-6GlcNAc transferase [UDP-GlcNAc:alpha-D-mannoside beta1, 6-N-acetylglucosaminyltransferase (GnT-V)]. Cell adhesion to fibronectin and phosphorylation of focal adhesion kinase (FAK), which are associated with alpha5beta1 integrin and involved in a cell survival signaling, were found to be increased in the cisplatin-resistant cells. Enhancement of the inhibition of cell adhesion and FAK phosphorylation also support the above data in GnT-V transfectants of HSC-2 cells. Interestingly, the differences in sensitivity to cisplatin and FAK phosphorylation between cisplatin-sensitive and -resistant cells were completely abolished by treatment with a neutral antibody of alpha5beta1 integrin. These results suggest that modification of oligosaccharides of alpha5beta1 integrin represents one of the possible mechanisms of drug resistance in head and neck cancer cells.
Nakahara
Susumu
S
Department of Biochemistry, Osaka University Graduate School of Medicine, Osaka, Japan.
Miyoshi
Eiji
E
Noda
Katsuhisa
K
Ihara
Shinji
S
Gu
Jianguo
J
Honke
Koichi
K
Inohara
Hidenori
H
Kubo
Takeshi
T
Taniguchi
Naoyuki
N
D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology; D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm; D005109:Extracellular Matrix / Q000187:drug effects; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D039081:Integrin alpha5beta1 / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*; D037102:Lectins / Q000378:metabolism; D009844:Oligosaccharides / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism; D011233:Precipitin Tests; D011505:Protein-Tyrosine Kinases / Q000378:metabolism
D039081:Integrin alpha5beta1; D037102:Lectins; D009844:Oligosaccharides; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; D002945:Cisplatin