Upregulation of glycolytic enzymes in proteins secreted from human colon cancer cells with 5-fluorouracil resistance

• Published in: Electrophoresis 2009-06, Vol.30 (12), p.2182-2192
• Main Authors: Shin, Young-Kyoung, Yoo, Byong Chul, Hong, Yong Sang, Chang, Hee Jin, Jung, Kyung Hae, Jeong, Seung-Yong, Park, Jae-Gahb
• Format: Article
• Language: English
• Subjects: 5‐Fluorouracil resistance; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols - therapeutic use; Camptothecin - administration & dosage; Camptothecin - analogs & derivatives; Cell Line, Tumor; Colon cancer; Colonic Neoplasms - drug therapy; Colonic Neoplasms - enzymology; Colonic Neoplasms - metabolism; Colonic Neoplasms - secretion; Down-Regulation; Drug Resistance, Neoplasm; Female; Fluorouracil - administration & dosage; Fluorouracil - pharmacology; Glycolysis; Glycolysis - drug effects; Humans; Leucovorin - administration & dosage; Male; Middle Aged; Neoplasm Proteins - biosynthesis; Neoplasm Proteins - metabolism; Neoplasm Proteins - secretion; Proteome - metabolism; Proteome - secretion; Pyruvate Kinase - metabolism; Pyruvate Kinase - secretion; Pyruvate kinase M2; Reproducibility of Results; Secreted proteins; Up-Regulation - drug effects
• ISSN: 0173-0835; 1522-2683
• DOI: 10.1002/elps.200800806

5-Fluorouracil (5-FU) is the most commonly used chemotherapeutic agent for colorectal cancer (CRC). However, resistance to this drug is a major obstacle in CRC chemotherapy. Accurate prediction of response to 5-FU would avoid unnecessary chemotherapy and allow the selection of other effective drugs. To identify a candidate predictor of 5-FU resistance, we isolated secreted proteins that were up- or downregulated in a 5-FU-resistant cancer cell line, compared with the parent cell line (SNU-C4), using a stable isotope-coded labeling protocol. For validating the clinical applicability of this method, levels of the identified proteins were determined in the sera of 46 patients treated with 5-FU. In total, 238 proteins with molecular weights ranging from 50 to 75 kDa were identified. Among these, 45 and 35 secreted proteins were up- and downregulated in the 5-FU-resistant cell line, respectively. We observed significant upregulation of glycolytic enzymes, including glyceraldehyde-3-phosphate dehydrogenase, pyruvate kinase M2 (PK-M2), transketolase, and NADP(+)-dependent malic enzyme 1. In particular, the level of PK-M2, a key enzyme in the glycolytic pathway, showed an increasing tendency in both sera and tissues from CRC patients displaying no response to 5-FU-based chemotherapy (progressive and stable disease cases), compared with that in complete or partial responders to 5-FU-based chemotherapy; however, it did not reach the statistical significance. In conclusion, increasing pattern of PK-M2 observed with 5-FU resistance induced in vitro and in sera and tissues from CRC patients displaying poor response to 5-FU-based chemotherapy suggest the relevance of dysregulated glycolysis and 5-FU-resistant CRC.