IkappaBalpha gene therapy in tumor necrosis factor-alpha- and chemotherapy-mediated apoptosis of hepatocellular carcinomas

M K Tietze, T Wuestefeld, Y Paul, L Zender, C Trautwein, M P Manns, S Kubicka
Cancer Gene Therapy 2000, 7 (10): 1315-23
The transcription factor nuclear factor kappaB (NFkappaB) is an essential antagonist of apoptosis during liver regeneration and embryonal development of hepatocytes. Several reports have indicated that NFkappaB may also inhibit the programmed cell death induced by cytokines, ionizing radiation, or cytotoxic drugs in some cancer cell lines. Because hepatocellular carcinomas (HCCs) are one of the most resistant tumors to systemic chemotherapy, we investigated the activation of NFkappaB and the consequence of its inhibition by an IkappaBalpha-super repressor during tumor necrosis factor alpha (TNFalpha)- and chemotherapy-induced apoptosis in HCC cell lines. We demonstrate that both TNFalpha and adriamycin activate NFkappaB in hepatoma cells. Activation of NFkappaB could be blocked through an adenoviral vector expressing the IkappaBalpha super repressor, regardless of the activating agent. Inhibition of NFkappaB enhanced the apoptosis induced by TNFalpha, whereas IkappaBalpha had an anti-apoptotic effect on chemotherapy-induced programmed cell death. A strong inhibition of chemotherapy- and TNFalpha-induced apoptosis by dominant-negative Fas-associated death domain indicated an essential contribution of death receptor-mediated apoptosis. To elucidate the different role of NFkappaB in chemotherapy-induced apoptosis, we investigated the expression of Fas (CD95) and Fas ligand (CD95 ligand), which have been described as important mediators of chemotherapy-induced cell death and as target genes of NFkappaB. However, our investigations demonstrated that in hepatoma cells, the chemotherapy-induced up-regulation of Fas (CD95) and Fas ligand (CD95 ligand) is not transcriptionally mediated through NFkappaB. Thus, other molecular mechanisms must account for the anti-apoptotic effect of IkappaBalpha in adriamycin-induced death of hepatoma cells. In summary, our investigations indicate that the activation of NFkappaB in response to cytotoxic drugs, in contrast to TNFalpha, exerts a pro-apoptotic stimulus rather than an anti-apoptotic function, which has implications for therapy of HCCs.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"