Akt associates with nuclear factor kappaB and plays an important role in chemoresistance of gastric cancer cells.
The ubiquitously expressed serine-threonine kinase Akt and the transcription factor NF-kappaB both are involved in cell proliferation and apoptosis. Furthermore, the activation of Akt or NF-kappaB has been suggested to associate with chemo-resistance of human tumors. The exact mechanism and interreaction of Akt and NF-kappaB pathway on chemoresistance in gastric cancer is still unknown. We explored the function of Akt and NF-kappaB pathway on chemoresistance in human gastric cancer cells. MTT method was used to analyze the influence of chemotherapeutics and the combined use of wortmannin or MG-132 on the growth of SGC-7901 cells. Apoptosis of SGC-7901 was detected by TUNEL and Annexin V/PI methods. The protein level of NF-kappaB was analyzed by immunocytochemical staining. EMSA was used to confirm the increased nuclear translocation of RelA. The protein level of p-Akt and p-IkappaBalpha were analyzed by Western blotting. Etoposide and doxorubicin suppressed the growth of SGC-7901 time and dose-dependently. Combined use of wortmannin or MG-132 can suppress growth further. Chemotherapeutics induced apoptosis of SGC-7901 and activated Akt and NF-kappaB, combined use of wortmannin or MG-132 induced apoptosis further and attenuated the activation of NF-kappaB. The combined use of wortmannin attenuated the activation of Akt, but combined use of MG-132 did not attenuate the activation of Akt. The activation of NF-kappaB is a branch mechanism of Akt anti-apoptosis effects. The chemotherapeutics induced apoptosis and induced the activation of Akt and NF-kappaB in SGC-7901 cell, suppression the activation of Akt or NF-kappaB can increase the effects of chemotherapeutics. NF-kappaB is a downstream target of Akt.
Department of Gastroenterology, Sir Run Run Shaw Affiliated Hospital of Zhejiang University, Hangzhou 310016, Zhejiang Province, PR China. ydycn08@yahoo.com.cn
Liang-Liang
LL
Yu
Ning
N
Dai
Hong-Gang
HG
Yu
Lei-Min
LM
Sun
Jian-Min
JM
Si
D000730:Androstadienes / Q000008:administration & dosage / Q000494:pharmacology; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology; D002277:Carcinoma / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D004247:DNA / Q000378:metabolism; D004353:Drug Evaluation, Preclinical; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D007976:Leupeptins / Q000008:administration & dosage / Q000494:pharmacology; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism* / Q000502:physiology; D051058:Oncogene Protein v-akt / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology*; D011485:Protein Binding / Q000502:physiology; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D014407:Tumor Cells, Cultured; D000077191:Wortmannin
D000730:Androstadienes; D004791:Enzyme Inhibitors; D020672:I-kappa B Proteins; D007976:Leupeptins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D000072000:NF-KappaB Inhibitor alpha; D004247:DNA; D051058:Oncogene Protein v-akt; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde; D000077191:Wortmannin