Modulation of curcumin-induced Akt phosphorylation and apoptosis by PI3K inhibitor in MCF-7 cells.
Curcumin has been shown to induce apoptosis in various malignant cancer cell lines. One mechanism of curcumin-induced apoptosis is through the PI3K/Akt signaling pathway. Akt, also known as protein kinase B (PKB), is a member of the family of phosphatidylinositol 3-OH-kinase regulated Ser/Thr kinases. The active Akt regulates cell survival and proliferation; and inhibits apoptosis. In this study we found that curcumin induces apoptotic cell death in MCF-7 cells, as assessed by MTT assay, DNA ladder formation, PARP cleavage, p53 and Bax induction. At apoptotic inducing concentration, curcumin induces a dramatic Akt phosphorylation, accompanied by an increased phosphorylation of glycogen synthase kinase 3beta (GSK3beta), which has been considered to be a pro-growth signaling molecule. Combining curcumin with PI3K inhibitor, LY290042, synergizes the apoptotic effect of curcumin. The inhibitor LY290042 was capable of attenuating curcumin-induced Akt phosphorylation and activation of GSK3beta. All together, our data suggest that blocking the PI3K/Akt survival pathway sensitizes the curcumin-induced apoptosis in MCF-7 cells.
Cell Signaling Laboratory, Department of Biochemistry, Faculty of Medicine and Health Sciences, UAE University, P.O. Box 17666, Al Ain, United Arab Emirates.
Jaleel
J
Kizhakkayil
Faisal
F
Thayyullathil
Shahanas
S
Chathoth
Abdulkader
A
Hago
Mahendra
M
Patel
Sehamuddin
S
Galadari
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology*; D003474:Curcumin / Q000494:pharmacology*; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D009025:Morpholines / Q000494:pharmacology*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
D000970:Antineoplastic Agents; D002867:Chromones; C549075:LY 290042; D009025:Morpholines; D000081082:Phosphoinositide-3 Kinase Inhibitors; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D011065:Poly(ADP-ribose) Polymerases; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D051057:Proto-Oncogene Proteins c-akt; D038362:Glycogen Synthase Kinase 3; D003474:Curcumin