Role of NF-kappaB and Akt/PI3K in the resistance of pancreatic carcinoma cell lines against gemcitabine-induced cell death.
Pancreatic cancer is resistant to almost all cytotoxic drugs. Currently, gemcitabine appears to be the only clinically active drug but, because of pre-existing or acquired chemoresistance of most of the tumor cells, it failed to significantly improve the outcome of pancreatic carcinoma patients. The current study examined the relevance of nuclear factor kappaB (NF-kappaB) and PI3K/Akt in the resistance of five pancreatic carcinoma cell lines towards gemcitabine. Treatment for 24 h with gemcitabine (0.04-20 micro M) led to a strong induction of apoptosis in PT45-P1 and T3M4 cells but not in BxPc-3, Capan-1 and PancTu-1 cells. These resistant cell lines exhibited a high basal NF-kappaB activity in contrast to the sensitive cell lines. Furthermore, gemcitabine showed a dose-dependent induction of NF-kappaB. At a dose of 0.04 micro M, gemcitabine still induced apoptosis in the sensitive cell lines, but did not induce NF-kappaB. In addition, NF-kappaB inhibition by MG132, sulfasalazine or the IkappaBalpha super-repressor strongly diminished the resistance against gemcitabine (0.04-20 micro M). In contrast to this obvious correlation between basal NF-kappaB activity and gemcitabine resistance, PI3K/Akt seems not to be involved in gemcitabine resistance of these cell lines. Neither did the basal Akt activity correlate with the sensitivity towards gemcitabine treatment, nor did the inhibition of PI3K/Akt by LY294002 alter gemcitabine-induced apoptosis. These results indicate that constitutive NF-kappaB activity confers resistance against gemcitabine and that modulation of this activity by pharmacological or genetic approaches may have therapeutical potential when combined with gemcitabine in the treatment of pancreatic carcinoma.
Arlt
Alexander
A
1Laboratory of Molecular Gastroenterology & Hepatology, 1st Department of Medicine, University of Kiel, Germany.
Gehrz
Andre
A
Müerköster
Susanne
S
Vorndamm
Jens
J
Kruse
Marie-Luise
ML
Fölsch
Ulrich R
UR
Schäfer
Heiner
H
D000230:Adenocarcinoma / Q000188:drug therapy* / Q000201:enzymology / Q000378:metabolism; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use / Q000633:toxicity*; D017209:Apoptosis; D002867:Chromones / Q000494:pharmacology; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000627:therapeutic use / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005047:Etoposide / Q000627:therapeutic use / Q000633:toxicity; D006801:Humans; D009025:Morpholines / Q000494:pharmacology; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000502:physiology*; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D051057:Proto-Oncogene Proteins c-akt; D014407:Tumor Cells, Cultured; D000093542:Gemcitabine
D000964:Antimetabolites, Antineoplastic; D002867:Chromones; D003841:Deoxycytidine; D004791:Enzyme Inhibitors; D005047:Etoposide; D009025:Morpholines; D016328:NF-kappa B; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D000093542:Gemcitabine; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C494918:AKT1 protein, human