Nuclear factor-kappa B is upregulated in colorectal cancer.
BACKGROUND
Chemoresistance may involve the anti-apoptotic transcriptional regulator, nuclear factor-kappa B (NF-kappa B). The purpose of this study was to determine whether chemotherapy induces NF-kappa B activation in a human colon cancer cell line (SW48) and whether NF-kappa B is constitutively activated in colorectal cancer.


METHODS
SW48 cells were incubated with gemcitabine hydrochloride (Gemzar) in the presence and absence of the 26s proteasome inhibitor, MG132, and NF-kappa B binding (electrophoretic mobility shift assay), DNA synthesis (tritiated thymidine uptake), cell viability (3-[4,5-dimethylthiazol-2-yl]-diphenyl-tetrazolium bromide assay), and apoptosis (caspase-3 activity) were measured at 24 hours. NF-kappa B binding (electrophoretic mobility shift assay) was also assayed in 10 colorectal cancer tumors.


RESULTS
SW48 cells demonstrated constitutive NF-kappa B binding that was enhanced by gemcitabine hydrochloride in a dose-dependent manner. MG132 inhibited NF-kappa B binding and enhanced gemcitabine hydrochloride's inhibition of DNA synthesis (gemcitabine hydrochloride = 73% +/- 1.4% vs gemcitabine hydrochloride + MG132 = 6% +/- 0.4%, P <.05), cell killing (gemcitabine hydrochloride = 87% +/- 2.0 vs gemcitabine hydrochloride + MG132 = 25% +/- 1.3%, P <.05), and caspase-3 activity (gemcitabine hydrochloride = 870 +/- 17.4 vs gemcitabine hydrochloride + MG132 = 1075 +/- 20.4, P <.05). NF-kappa B binding was increased in 8 of 10 colorectal cancer tumors compared with adjacent normal mucosa.


CONCLUSIONS
Gemcitabine hydrochloride enhances NF-kappa B binding in a colorectal cancer cell line, whereas inhibition of NF-kappa B enhances gemcitabine hydrochloride's antitumor activity. NF-kappa B is also activated in human colorectal cancer. NF-kappa B may identify chemoresistant tumors, whereas inhibition of NF-kappa B may be a novel, biologically based therapy. (Surgery 2001;130:363-9).
Lind
D S
DS
Department of Surgery, Division of Gastroenterology, University of Florida College of Medicine, Gainesville, FL 32610, USA.
Hochwald
S N
SN
Malaty
J
J
Rekkas
S
S
Hebig
P
P
Mishra
G
G
Moldawer
L L
LL
Copeland
E M
EM
Mackay
S
S
D000964:Antimetabolites, Antineoplastic / Q000633:toxicity; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D003106:Colon / Q000378:metabolism / Q000473:pathology; D015179:Colorectal Neoplasms / Q000378:metabolism / Q000473:pathology*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004247:DNA / Q000096:biosynthesis; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000633:toxicity; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology; D007976:Leupeptins / Q000494:pharmacology; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D012007:Rectum / Q000378:metabolism / Q000473:pathology; D014407:Tumor Cells, Cultured; D000093542:Gemcitabine
D000964:Antimetabolites, Antineoplastic; D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D016328:NF-kappa B; D003841:Deoxycytidine; D004247:DNA; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde; D000093542:Gemcitabine