Mucin production determines sensitivity to bortezomib and gemcitabine in pancreatic cancer cells.

Abstract

The prognosis of pancreatic cancer remains disappointing due to a high intrinsic resistance against chemotherapeutic agents. Standard gemcitabine therapies have improved overall survival only marginally and recently, inhibition of the proteasome by the boronic acid derivative bortezomib has been introduced as a novel therapeutic strategy for solid and hematological malignancies including pancreatic cancer. The mucus-producing pancreatic cancer cell line Capan-1 was cultured under standard conditions and treated with different concentrations of gemcitabine or bortezomib. Mucus production was suppressed by siRNA-mediated silencing of apomucin genes. Cell proliferation was determined by 3H-thymidine incorporation and apoptosis was quantified after propidium iodide staining by flow cytometry. Apoptotic cell death was confirmed by TUNEL staining, determination of mitochondrial transmembrane potential and assessment of caspase 3/7 activity. NFκB-activity was determined by EMSA. The unfolded protein response (UPR) was further investigated by PCR, Western blotting and caspase 12 activity assays. Silencing of MUC4 significantly reduced expression of mucins for up to 5 days after transfection. While native cells showed an increased sensitivity to bortezomib treatment, silenced cells were more sensitive to gemcitabine treatment. Bortezomib induces mitochondrial damage in native cells and also activates the UPR by splicing of Xbp-1 and induction of CHOP, which is significantly reduced by silencing of MUC4. Our data suggest that mucinous pancreatic cancers are more sensitive towards proteasome inhibition by bortezomib and that alternative pathways of apoptosis are involved in cell death induction, while tumor cells with a low secretory activity show a better response to gemcitabine.

• Authors: Thaddäus Till Wissniowski, Silke Meister, Eckhart G Hahn, Joachim R Kalden, Reinhard Voll, Matthias Ocker
• Journal: International journal of oncology (Int J Oncol) Vol. 40 Issue 5 Pg. 1581-9 (May 2012) ISSN: 1791-2423 [Electronic] Greece
• PMID: 22266985 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antimetabolites, Antineoplastic
• Boronic Acids
• DDIT3 protein, human
• DNA-Binding Proteins
• Mucins
• NF-kappa B
• Protease Inhibitors
• Pyrazines
• Regulatory Factor X Transcription Factors
• Transcription Factors
• X-Box Binding Protein 1
• XBP1 protein, human
• Deoxycytidine
• Transcription Factor CHOP
• Bortezomib
• CASP12 protein, human
• CASP3 protein, human
• CASP7 protein, human
• Caspase 12
• Caspase 3
• Caspase 7
• Gemcitabine

Topics

• Antimetabolites, Antineoplastic (pharmacology)
• Apoptosis (drug effects)
• Blotting, Western
• Boronic Acids (pharmacology)
• Bortezomib
• Carcinoma, Pancreatic Ductal (genetics, metabolism, pathology)
• Caspase 12 (metabolism)
• Caspase 3 (metabolism)
• Caspase 7 (metabolism)
• Cell Line, Tumor
• Cell Proliferation (drug effects)
• DNA-Binding Proteins (metabolism)
• Deoxycytidine (analogs & derivatives, pharmacology)
• Dose-Response Relationship, Drug
• Electrophoretic Mobility Shift Assay
• Endoplasmic Reticulum (drug effects, metabolism)
• Flow Cytometry
• Humans
• In Situ Nick-End Labeling
• Membrane Potential, Mitochondrial (drug effects)
• Mitochondria (drug effects, metabolism)
• Mucins (genetics, metabolism)
• NF-kappa B (metabolism)
• Pancreatic Neoplasms (genetics, metabolism, pathology)
• Polymerase Chain Reaction
• Protease Inhibitors (pharmacology)
• Pyrazines (pharmacology)
• RNA Interference
• Regulatory Factor X Transcription Factors
• Time Factors
• Transcription Factor CHOP (metabolism)
• Transcription Factors (metabolism)
• Transfection
• Unfolded Protein Response (drug effects)
• X-Box Binding Protein 1
• Gemcitabine