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Augmented adriamycin sensitivity in cells transduced with an antisense tumor necrosis factor gene is mediated by
M Sasaki1, D Kobayashi, N Watanabe
1Division of Laboratory Diagnosis, Sapporo Medical University School of Medicine, South-1 West-16, Chuo-ku, Sapporo 060-0061, Japan.
Abstract:
While transduction of an antisense tumor necrosis factor (TNF) gene sequence can augment the cytotoxicity of adriamycin (ADM) in human cancer cells, the specific effect of introducing this sequence on the signal transduction pathway leading to cell death remains unclear. In ADM-resistant pancreatic carcinoma (PANC-1) cells, both the antioxidant N-acetyl-L-cysteine (NAC) and the caspase-3 inhibitor acetyl-L-aspartyl-L-methionyl-L-glutaminyl-L-aspartyl-aldehyde (Ac-DMQD-CHO) prevented ADM-induced cytotoxicity. NAC additionally inhibited caspase-3 activity induced by ADM treatment, while Ac-DMQD-CHO showed no suppressive effect on reactive oxygen species (ROS). Stable antisense-TNF transfectants showed higher ADM sensitivity and greater ADM-induced ROS production and caspase-3 activity than mock transfectant or parent cells. These results indicate that increased caspase-3 activity downstream from ROS production is among the mechanisms by which transduction of the antisense TNF sequence of augments ADM sensitivity of pancreatic carcinoma cells.
Insights
Introducing an antisense tumor necrosis factor (TNF) gene sequence enhances adriamycin (ADM) effectiveness in pancreatic cancer cells. This occurs through increased reactive oxygen species (ROS) production and subsequent caspase-3 activation, improving ADM sensitivity.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Adriamycin (ADM) resistance is a significant challenge in pancreatic cancer treatment.
- Antisense tumor necrosis factor (TNF) gene transduction can enhance ADM cytotoxicity.
- The precise signal transduction pathway affected by antisense TNF in ADM-treated cells is not fully understood.
Purpose of the Study:
- To elucidate the role of reactive oxygen species (ROS) and caspase-3 in ADM-induced cytotoxicity in pancreatic cancer cells with antisense TNF gene transduction.
- To investigate the mechanism by which antisense TNF enhances ADM sensitivity.
Main Methods:
- Utilized ADM-resistant pancreatic carcinoma (PANC-1) cells.
- Administered N-acetyl-L-cysteine (NAC) as an antioxidant and Ac-DMQD-CHO as a caspase-3 inhibitor.
- Created stable antisense-TNF transfectants and compared them with mock transfectants and parent cells.
- Measured ADM-induced cytotoxicity, ROS production, and caspase-3 activity.
Main Results:
- Both NAC and Ac-DMQD-CHO inhibited ADM-induced cytotoxicity in PANC-1 cells.
- NAC suppressed ADM-induced caspase-3 activity, while Ac-DMQD-CHO did not affect ROS levels.
- Antisense-TNF transfectants exhibited increased ADM sensitivity, ROS production, and caspase-3 activity compared to controls.
- Caspase-3 activity was found to be downstream of ROS production.
Conclusions:
- Increased caspase-3 activity, downstream of ROS production, is a key mechanism enhancing ADM sensitivity in pancreatic cancer cells via antisense TNF gene transduction.
- This study provides insights into overcoming ADM resistance in pancreatic cancer.