Interferon gamma inhibits growth of human pancreatic carcinoma cells via caspase-1 dependent induction of apoptosis.
OBJECTIVE
The poor prognosis of pancreatic cancer is partly due to resistance to a broad spectrum of apoptotic stimuli. To identify intact proapoptotic pathways of potential clinical relevance, we characterised the effects of interferon gamma (IFN-gamma) on growth and survival in human pancreatic cancer cells.


METHODS
IFN-gamma receptor expression and signal transduction were examined by reverse transcriptase-polymerase chain reaction (RT-PCR), immunoprecipitation, western blot analysis, and transactivation assays. Effects on cell growth and survival were evaluated in terms of cell numbers, colony formation, cell cycle analysis, DNA fragmentation, and poly(ADP ribose) polymerase (PARP) cleavage.


RESULTS
All four pancreatic cancer cell lines examined expressed functional IFN-gamma receptors and downstream effectors, including the putative tumour suppressor interferon regulatory factor 1 (IRF-1). IFN-gamma treatment profoundly inhibited anchorage dependent and independent growth of pancreatic cancer cells. Cell cycle analyses revealed subdiploid cells suggesting apoptosis, which was confirmed by demonstration of DNA fragmentation and PARP cleavage. Time and dose dependency of apoptosis induction and growth inhibition correlated closely, identifying apoptosis as the main, if not exclusive, mechanism responsible for growth inhibition. Apoptosis was preceded by upregulation of procaspase-1 and accompanied by proteolytic activation. Furthermore, the caspase inhibitor z-vad-fmk completely prevented IFN-gamma mediated apoptosis.


CONCLUSIONS
These results identify an intact proapoptotic pathway in pancreatic cancer cells and suggest that IRF-1 and/or procaspase-1 may represent potential therapeutic targets to be further explored.
Detjen
K M
KM
Medizinische Klinik mit Schwerpunkt Hepatologie und Gastroenterologie, Universitätsklinikum Charité, Campus Virchow Klinikum, Humboldt Universität zu Berlin, Augustenburger Platz 1, 13353 Berlin, Germany.
Farwig
K
K
Welzel
M
M
Wiedenmann
B
B
Rosewicz
S
S
D000704:Analysis of Variance; D017209:Apoptosis / Q000502:physiology*; D015153:Blotting, Western; D020170:Caspase 1 / Q000502:physiology*; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007371:Interferon-gamma / Q000627:therapeutic use*; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D011233:Precipitin Tests; D017471:Receptors, Interferon / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology; D015533:Transcriptional Activation / Q000502:physiology; D014407:Tumor Cells, Cultured / Q000187:drug effects; D015854:Up-Regulation
D017471:Receptors, Interferon; D007371:Interferon-gamma; D020170:Caspase 1