Synergy of gemcitabine and lidamycin associated with NF-kappaB downregulation in pancreatic carcinoma cells.
OBJECTIVE
To investigate the effects on human pancreatic cancer PANC-1 and SW1990 cells using a combination of lidamycin (LDM) and gemcitabine.


METHODS
A 3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to determine the growth inhibition of drugs in PANC-1 and SW1990 cells. The effects on apoptosis were measured by terminal uridine deoxynucleotidyl transferase dUTP nick end labeling assay and flow cytometry combined with fluorescein- isothiocyanate-Annexin V/propidium iodide staining. The activity of caspase-3 was measured with a special assay kit. The mitochondrial membrane potential was determined by confocal microscopy analyses. The level of mRNA encoding K-ras in the cells was determined by RT-PCR analysis. The expression of K-ras, NF-kappaB, and Bcl-2 was detected by Western blotting analysis.


RESULTS
There was a significant reduction in proliferation in the pancreatic cancer cell lines treated with a combination of gemcitabine and LDM. The overall growth inhibition directly correlated with apoptotic cell death. LDM potentiated the gemcitabine-induced cell killing by reducing mitochondrial membrane potential and increasing the caspase-3 activity. Notably, the K-ras mRNA level was significantly reduced with the combination of gemcitabine and LDM. The results for K-ras, NF-kappaB, and Bcl-2 proteins also showed downregulation in the combination group relative to the single-agent treatment and the untreated control.


CONCLUSIONS
LDM can potentiate the growth inhibition induced by gemcitabine in human pancreatic cancer cells, and the synergy may be associated with NF-kappaB downregulation.
Chen
Jing
J
Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
Wu
Shu-Ying
SY
Ou-Yang
Zhi-Gang
ZG
Zhen
Yong-Su
YS
D000617:Aminoglycosides / Q000494:pharmacology*; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001562:Benzimidazoles / Q000378:metabolism; D002232:Carbocyanines / Q000378:metabolism; D002277:Carcinoma / Q000235:genetics; D053148:Caspase 3 / Q000032:analysis / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D015536:Down-Regulation; D004357:Drug Synergism; D053281:Enediynes / Q000494:pharmacology*; D005456:Fluorescent Dyes / Q000378:metabolism; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D000093542:Gemcitabine
D000617:Aminoglycosides; D000964:Antimetabolites, Antineoplastic; D001562:Benzimidazoles; D002232:Carbocyanines; D053281:Enediynes; D005456:Fluorescent Dyes; D016328:NF-kappa B; D012333:RNA, Messenger; D003841:Deoxycytidine; C058024:C 1027; C068624:5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine; D053148:Caspase 3; D000093542:Gemcitabine