The MUC4 mucin mediates gemcitabine resistance of human pancreatic cancer cells via the Concentrative Nucleoside Transporter family

• Published in: Oncogene Vol. 32; no. 13; pp. 1714 - 1723
• Main Authors: Skrypek, N, Duchêne, B, Hebbar, M, Leteurtre, E, van Seuningen, I, Jonckheere, N
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 28.03.2013; Nature Publishing Group; Nature Publishing Group [1987-....]
• Subjects: 631/67/1059/2326; 631/67/1059/99; 631/67/1504/1713; Adenocarcinoma; Adenocarcinoma - drug therapy; Adenocarcinoma - genetics; Adenocarcinoma - pathology; Aged; Antimetabolites, Antineoplastic - therapeutic use; Apoptosis; Bax protein; Cancer; Cell Biology; Cell Line, Tumor; Cell number; Chemotherapy; Deoxycytidine - analogs & derivatives; Deoxycytidine - therapeutic use; Deoxycytidine kinase; Drug resistance; Drug Resistance, Neoplasm - genetics; Drug therapy; Equilibrative Nucleoside Transporter 1 - genetics; Equilibrative Nucleoside Transporter 1 - metabolism; Equilibrative Nucleoside Transporter 1 - physiology; Female; Gemcitabine; Gene Expression Regulation, Neoplastic - physiology; Gene Knockdown Techniques; Health aspects; Human Genetics; Humans; Internal Medicine; Kinases; Life Sciences; Male; MAP kinase; Medicine; Medicine & Public Health; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; Membrane Transport Proteins - physiology; Middle Aged; Models, Biological; Mucin; Mucin-4 - genetics; Mucin-4 - physiology; Mucins; Multigene Family - genetics; Multigene Family - physiology; NF-κB protein; Nucleoside transporter; Oncology; original-article; Pancreatic cancer; Pancreatic Neoplasms - drug therapy; Pancreatic Neoplasms - genetics; Pancreatic Neoplasms - pathology; Physiological aspects; Proteins; Tetrazolium salt; Tumor cell lines; Tumor cells; Tumors; Western blotting; France; NF-κB; hCNT1; pancreatic cancer; gemcitabine; MUC4; mucin
• ISSN: 0950-9232; 1476-5594
• DOI: 10.1038/onc.2012.179

The fluorinated analog of deoxycytidine, Gemcitabine (Gemzar), is the main chemotherapeutic drug in pancreatic cancer, but survival remains weak mainly because of the high resistance of tumors to the drug. Recent works have shown that the mucin MUC4 may confer an advantage to pancreatic tumor cells by modifying their susceptibility to drugs. However, the cellular mechanism(s) responsible for this MUC4-mediated resistance is unknown. The aim of this work was to identify the cellular mechanisms responsible for gemcitabine resistance linked to MUC4 expression. CAPAN-2 and CAPAN-1 adenocarcinomatous pancreatic cancer (PC) cell lines were used to establish stable MUC4-deficient clones (MUC4-KD) by shRNA interference. Measurement of the IC 50 index using tetrazolium salt test indicated that MUC4-deficient cells were more sensitive to gemcitabine. This was correlated with increased Bax/Bcl XL ratio and apoptotic cell number. Expression of Equilibrative/Concentrative Nucleoside Transporter (hENT1, hCNT1/3), deoxycytidine kinase (dCK), ribonucleotide reductase (RRM1/2) and Multidrug-Resistance Protein (MRP3/4/5) was evaluated by quantitative RT–PCR (qRT–PCR) and western blotting. Alteration of MRP3, MRP4, hCNT1 and hCNT3 expression was observed in MUC4-KD cells, but only hCNT1 alteration was correlated to MUC4 expression and sensitivity to gemcitabine. Decreased activation of MAPK, JNK and NF-κB pathways was observed in MUC4-deficient cells, in which the NF-κB pathway was found to have an important role in both sensitivity to gemcitabine and hCNT1 regulation. Finally, and in accordance with our in vitro data, we found that MUC4 expression was conversely correlated to that of hCNT1 in tissues from patients with pancreatic adenocarcinoma. This work describes a new mechanism of PC cell resistance to gemcitabine, in which the MUC4 mucin negatively regulates the hCNT1 transporter expression via the NF-κB pathway. Altogether, these data point out to MUC4 and hCNT1 as potential targets to ameliorate the response of pancreatic tumors to gemcitabine treatment.