Leukotriene B4 receptor antagonist LY293111 inhibits proliferation and induces apoptosis in human pancreatic cancer cells.
OBJECTIVE
The effects of leukotriene (LT) B4 and its receptor antagonist LY293111 on proliferation and apoptosis of human pancreatic cancer cells were investigated, both in vitro and in vivo.


METHODS
Six human pancreatic cancer cell lines (MiaPaCa-2, HPAC, Capan-1, Capan-2, PANC-1, and AsPC-1) were used. Expression of LTB4 receptors, BLT1 and BLT2, was measured by reverse transcription-PCR. Cell proliferation was measured by [methyl-(3)H]thymidine incorporation and cell number counting. Extracellular signal-regulated kinase (ERK) 1/2 activation was measured by Western blotting. Apoptosis was assessed by morphology, terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay, and poly(ADP-ribose) polymerase cleavage. The effect of LY293111 on growth of AsPC-1 and HPAC cell xenografts was assessed in BALB/c nu/nu athymic mice.


RESULTS
Both LTB4 receptor types were found to be expressed in human pancreatic cancer cells. The LTB4 receptor antagonist LY293111 caused both time- and concentration-dependent inhibition of proliferation of all six human pancreatic cancer cell lines studied. In contrast, LTB4 stimulated proliferation of these cell lines and induced ERK1/2 phosphorylation. The growth-stimulatory effect and ERK1/2 phosphorylation induced by LTB4 were inhibited by LY293111. Coincident with growth inhibition, LY293111 induced apoptosis in these pancreatic cancer cell lines, as indicated by morphology, TUNEL assay, and poly(ADP-ribose) polymerase cleavage. In studies using AsPC-1 and HPAC cell xenografts in athymic mice, LY293111 treatment markedly inhibited tumor growth over a 24-day treatment period, as measured by both tumor volume and tumor weight. In situ tissue TUNEL assay showed massive apoptosis in LY293111-treated tumor tissues.


CONCLUSIONS
LTB4 can directly regulate the growth of human pancreatic cancer cells and control their survival. Additional studies will clarify the underlying mechanisms of LTB4-regulated pancreatic cancer cell growth and apoptosis. LTB4 receptor blockade and inhibition of the downstream signal pathway are likely to be valuable for the treatment of human pancreatic cancer.
Tong
Wei-Gang
WG
Department of Surgery, Northwestern University Medical School, Chicago, Illinois 60611, USA.
Ding
Xian-Zhong
XZ
Hennig
Rene
R
Witt
Richard C
RC
Standop
Jens
J
Pour
Parviz M
PM
Adrian
Thomas E
TE
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001565:Benzoates / Q000494:pharmacology*; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects; D005260:Female; D006801:Humans; D020287:In Situ Nick-End Labeling; D066298:In Vitro Techniques; D007975:Leukotriene B4 / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008859:Microscopy, Polarization; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D018102:Receptors, Leukotriene B4 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D014407:Tumor Cells, Cultured
D001565:Benzoates; C094099:LY 293111; D018102:Receptors, Leukotriene B4; D007975:Leukotriene B4; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases