The dietary isothiocyanate sulforaphane targets pathways of apoptosis, cell cycle arrest, and oxidative stress in human pancreatic cancer cells and inhibits tumor growth in severe combined immunodeficient mice.
Anticancer effects of the dietary isothiocyanate sulforaphane were investigated in the human pancreatic cancer cell lines MIA PaCa-2 and PANC-1. Sulforaphane-treated cells accumulated in metaphase as determined by flow cytometry [4C DNA content, cyclin A(-), cyclin B1(+), and phospho-histone H3 (Ser(10))(+)]. In addition, treated cells showed nuclear apoptotic morphology that coincided with an activation of caspase-8, loss of mitochondrial membrane potential, and loss of plasma membrane integrity. The initial detection of caspase-3 cleavage occurring in G(2)-M arrest was independent of a change in phospho-cdc2 (Tyr(15)) protein; consequently, sulforaphane treatment combined with UCN-01 had no significant impact on cellular toxicity. Incubations at higher sulforaphane doses (>10 micromol/L) resulted in cleavage of caspase-3 in the G(1) subpopulation, suggesting that the induction of apoptosis and the sulforaphane-induced mitosis delay at the lower dose are independently regulated. Cellular toxicity in MIA PaCa-2, and to a greater extent in PANC-1, was positively correlated with a decrease in cellular glutathione levels, whereas sustained increases in glutathione observed in MIA PaCa-2 cells or the simultaneous incubation with N-acetyl-L-cysteine in PANC-1 cells were associated with resistance to sulforaphane-induced apoptosis. Daily sulforaphane i.p. injections (375 micromol/kg/d for 3 weeks) in severe combined immunodeficient mice with PANC-1 s.c. tumors resulted in a decrease of mean tumor volume by 40% compared with vehicle-treated controls. Our findings suggest that, in addition to the known effects on cancer prevention, sulforaphane may have activity in established pancreatic cancer.
Pham
Nhu-An
NA
Department of Medical Biophysics, University of Toronto, Ontario, Canada.
Jacobberger
James W
JW
Schimmer
Aaron D
AD
Cao
Pinjiang
P
Gronda
Marcella
M
Hedley
David W
DW
D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D000941:Antigens / Q000737:chemistry; D017209:Apoptosis; D015153:Blotting, Western; D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D005434:Flow Cytometry; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D017879:Isothiocyanates; D008297:Male; D008564:Membrane Potentials; D051379:Mice; D016513:Mice, SCID; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism; D008938:Mitosis; D009368:Neoplasm Transplantation; D009369:Neoplasms / Q000473:pathology*; D018384:Oxidative Stress; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D017382:Reactive Oxygen Species; D019311:Staurosporine / Q000031:analogs & derivatives* / Q000494:pharmacology; D013454:Sulfoxides; D013861:Thiocyanates / Q000494:pharmacology*; D013997:Time Factors; D014443:Tyrosine / Q000737:chemistry
D016588:Anticarcinogenic Agents; D000941:Antigens; D017879:Isothiocyanates; D017382:Reactive Oxygen Species; D013454:Sulfoxides; D013861:Thiocyanates; D014443:Tyrosine; C054852:7-hydroxystaurosporine; D004247:DNA; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C505409:Casp3 protein, mouse; C505526:Casp8 protein, mouse; D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases; C016766:sulforaphane; D005978:Glutathione; D019311:Staurosporine