Identification of carbonic anhydrase 9 as a contributor to pingyangmycin-induced drug resistance in human tongue cancer cells.
Drug resistance is the major obstacle to successful cancer treatment. To understand the mechanisms responsible for drug resistance in tongue cancer, Tca8113 cells derived from moderately differentiated human tongue squamous cell carcinoma were exposed to stepwise escalated concentrations of pingyangmycin (PYM) to develop the resistant cell line called Tca8113/PYM, which showed over 18.78-fold increased resistance to PYM as compared with Tca8113 cells, and cross-resistance to cisplatin, pirarubicin, paclitaxel, adriamycin, and mitomycin. We found that the resistance was not associated with multidrug resistance transporter 1 (p170, p-gp), multidrug resistance-associated protein 1 and breast cancer resistance protein overexpression, so we hypothesized that Tca8113/PYM cells must have some other resistance mechanism selected by PYM. To test this hypothesis, the global gene expression profiles between Tca8113 and Tca8113/PYM cells were compared by cDNA microarray. Eighty-nine genes and thirteen expressed sequence tags with differential expression levels between the two cell lines were identified. Some differential expression levels were validated with real-time PCR and western blot. Furthermore, the functional validation showed that both carbonic anhydrase (CA) inhibitor acetazolamide application and CA9 silencing with CA9 antisense oligonucleotides contribute to the medium pH increase of Tca8113/PYM cells and enhanced PYM chemosensitivity. Moreover, both acetazolamide and CA9 antisense oligonucleotides significantly increased PYM-induced caspase 3 activation in Tca8113/PYM cells. Thus, our study suggests that the resistance of Tca8113/PYM cells is probably associated with CA9 and other differential expression molecules, and that CA9 may be an important marker for prediction of PYM responsiveness in tongue cancer chemotherapy.
Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, Hunan, China.
Guopei
G
Zheng
Min
M
Zhou
Xinrong
X
Ou
Bo
B
Peng
Yanhui
Y
Yu
Fangren
F
Kong
Yongmei
Y
Ouyang
Zhimin
Z
He
D000086:Acetazolamide / Q000494:pharmacology; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism*; D001761:Bleomycin / Q000031:analogs & derivatives* / Q000494:pharmacology; D015153:Blotting, Western; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D016376:Oligonucleotides, Antisense / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014062:Tongue Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology
D000903:Antibiotics, Antineoplastic; D000951:Antigens, Neoplasm; D016376:Oligonucleotides, Antisense; D001761:Bleomycin; C025703:bleomycetin; C089226:CA9 protein, human; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases; D000086:Acetazolamide