Neuroprotective effects of astaxanthin against oxygen and glucose deprivation damage via the PI3K/Akt/GSK3β/Nrf2 signalling pathway in vitro

Astaxanthin (ATX), which is the most abundant flavonoid in propolis, has previously shown neuroprotective properties against cerebral ischaemia‐induced apoptosis. However, the mechanisms by which ATX mediates its therapeutic effects are unclear. At present, we explored the underlying mechanisms involved in the protective effects of ATX via the phosphoinositide 3‐kinase (PI3K)/Akt/glycogen synthase kinase 3 beta (GSK3β)/nuclear factor erythroid 2‐related factor 2 (Nrf2) signalling pathway in SH‐SY5Y cells. The PI3K/Akt inhibitor LY294002 and GSK3β inhibitor LiCl were employed in this study. Pre‐treatment with ATX for 24 hours significantly decreased the oxygen and glucose deprivation (OGD)‐induced viability loss, reduced the proportion of apoptosis and regulated OGD‐mediated reactive oxygen species (ROS) production. Furthermore, ATX suppressed OGD‐caused mitochondrial membrane potential and decomposition of caspase‐3 to cleaved caspase‐3, and heightened the B‐cell lymphoma 2 (Bcl‐2)/Bax ratio. PI3K/Akt/GSK3β/Nrf2 signalling pathway activation in SH‐SY5Y cells was verified by Western blot. ATX and LiCl treatment raised the protein levels of p‐Akt, p‐GSK3β, nucleus Nrf2 and haeme oxygenase 1 (HO‐1). However, these protein expression levels decreased by treatment of LY294002. The above in vitro data indicate that ATX can confer neuroprotection against OGD‐induced apoptosis via the PI3K/Akt/GSK3β/Nrf2 signalling pathway.     

14-3-3 proteins regulate glycogen synthase 3beta phosphorylation and inhibit cardiomyocyte hypertrophy

14-3-3 proteins are dimeric phophoserine-binding molecules that participate in important cellular processes such as cell proliferation, cell-cycle control and the stress response. In this work, we report that several isoforms of 14-3-3s are expressed in neonatal rat cardiomyocytes. To understand their function, we utilized a general 14-3-3 peptide inhibitor, R18, to disrupt 14-3-3 functions in cardiomyocytes. Cardiomyocytes infected with adenovirus-expressing YFP-R18 (AdR18) exhibited markedly increased protein synthesis and atrial natriuretic peptide production and potentiated the responses to norepinephrine stimulation. This response was blocked by the pretreatment with LY294002, a phosphoinositide 3-kinase (PI3K) inhibitor. Consistent with a role of PI3K in the R18 effect, R18 induced phosphorylation of a protein cloned from the vakt oncogene of retrovirus AKT8 (Akt - also called protein kinase B, PKB) at Ser473 and glycogen synthase 3beta (GSK3beta) at Ser9, but not extracellular signal-regulated kinase 1/2 (ERK1/2). AdR18-induced PKB and GSK3beta phosphorylation was completely blocked by LY294002. In addition, a member of the nuclear factor of activated T cells (NFAT) family, NFAT3, was converted into faster mobility forms and translocated into the nucleus upon the treatment of AdR18. These results suggest that 14-3-3s inhibits cardiomyocytes hypertrophy through regulation of the PI3K/PKB/GSK3beta and NFAT pathway.     

NMDA neuroprotection against a phosphatidylinositol-3 kinase inhibitor, LY294002 by NR2B-mediated suppression of glycogen synthase kinase-3beta-induced apoptosis

To identify the intracellular signaling pathways that mediate the pro-survival activity of NMDA receptors (NMDARs), we studied effects of exogenous NMDA on cultured rat cortical and hippocampal neurons that were treated with a phosphatidylinositol-3-kinase (PI3K) inhibitor, LY294002. NMDA at 5 or 10 microm protected against LY294002-induced apoptosis, suggesting NMDAR-mediated activation of a survival signaling pathway that is PI3K-independent. NR2B-specific NMDAR blockers antagonized anti-apoptotic effects of NMDA, indicating a critical role of NR2B NMDARs in the neuroprotection. NMDA at 10 microm suppressed LY294002-induced activation of a pro-apoptotic kinase, glycogen synthase kinase 3beta (GSK3beta). GSK3beta activation by LY294002 was associated with decreased levels of inhibitory GSK3beta phosphorylation at the Ser9 residue. However, NMDA did not prevent the LY294002-mediated decline of phospho-Ser9 levels. In addition, NMDA inhibited cortical neuron apoptosis induced by the overexpression of either wild type (wt) or Ser9Ala mutant form of GSK3beta, suggesting that NMDA suppressed GSK3beta in a Ser9-independent manner. Finally, inhibition of NR2B NMDARs reduced the NMDA protection against overexpression of GSK3betawt. These data indicate that moderate stimulation of NR2B NMDAR protects against inhibition of PI3K by a Ser9-independent inhibition of the pro-apoptotic activity of GSK3beta. Hence, the activation of NR2B and the Ser9-independent inhibition of GSK3beta are two newly identified elements of the signaling network that mediates the pro-survival effects of NMDA.     

Study of the pathways involved in apoptosis induced by PI3K inhibition in cerebellar granule neurons

In the present study we focused in the PI3K/Akt pathway which plays a key role in neuronal survival. Here we show that inhibition of PI3K/Akt by means of LY294002 induces apoptosis via a caspase-dependent and calpain-independent pathway in cerebellar granule neurons (CGNs). This finding was confirmed using zVAD-fmk, a widely caspase inhibitor that prevents apoptosis. For this purpose, we compared two models of apoptosis in CGNs, namely inhibition of PI3K/Akt, and serum potassium deprivation (S/K deprivation). In contrast to the S/K deprivation model, caspase-3 was not activated when PI3K is inhibited. Likewise, CDK5 activation was not involved in this apoptotic process, because calpain activation is responsible for the formation of CDK5/p25 neurotoxic form. However, S/K deprivation activated calpain, as it is shown by α-spectrin breakdown, and favoured the formation of CDK5/p25. Moreover, although PI3K/Akt inhibition enhanced pRbser780 phosphorylation, no increase in the expression of cell-cycle proteins, namely: cyclin D, cyclin E, CDK2 or CDK4, was detected. Furthermore, BrdU incorporation assay did not shown any increase in DNA synthesis. Likewise, PI3K/Akt inhibition increased GSK3β activity and c-Jun phosphorylation, which implicates these two pathways in this apoptotic route. Although previous reports suggest that apoptosis induced in CGNs by LY294002 and S/K deprivation causes PI3K inhibition and increases GSK3β activity and c-Jun phosphorylation activation, our results demonstrate substantial differences between them and point to a key role of GSK3β in the apoptosis induced in CGNs in the two models tested.     

低浓度哇巴因对负鼠肾小管上皮细胞增殖的影响

目的:用低血清培养液来模拟肾脏供血不足的营养不良状态,研究低浓度哇巴因对低血清培养下OK细胞(负鼠肾小管上皮细胞)增殖的影响。方法:用低浓度哇巴因(1-30n M)处理0.2%血清培养下OK细胞,MTT实验和Brdu掺入法检测哇巴因对OK细胞增殖的影响;Western blot检测Akt和ERK1/2的磷酸化水平;用LY294002和PD98059分别抑制PI3K/Akt和ERK1/2蛋白激酶活性,观察抑制PI3K/Akt和ERK1/2对哇巴因促进OK细胞增殖的影响。结果:低浓度哇巴因(1-30n M)促进OK细胞的增值,上调OK细胞中Akt和ERK1/2磷酸化水平。用LY294002和PD98059特异抑制Akt和ERK1/2的活化能够抑制哇巴因的促增殖作用。结论:低浓度哇巴因(1-10n M)能够促进OK细胞的增值,PI3K/Akt和ERK1/2信号通路参与哇巴因对OK细胞促增殖作用的调节。     

L-leucine increases [3H]-thymidine incorporation in chicken hepatocytes: involvement of the PKC, PI3K/Akt, ERK1/2, and mTOR signaling pathways

This study examined how L-leucine affected DNA synthesis and cell cycle regulatory protein expression in cultured primary chicken hepatocytes. L-Leucine promoted DNA synthesis in a dose- and time-dependent manner, with concomitant increases in cyclin D1 and cyclin E expression. Phospholipase C (PLC) and protein kinase C (PKC) mediated the L-leucine-induced increases in [3H]-thymidine incorporation and cyclin D1/CDK4 and cyclin E/CDK2 expression, as U73122 (a PLC inhibitor) or bisindolylmaleimide I (a PKC blocker) inhibited these effects. L-Leucine also increased PKC phosphorylation and intracellular Ca2+ levels. L-Leucine-mediated increases in [3H]-thymidine incorporation and cyclin/CDK expression were sensitive to LY 294002 (PI3K inhibitor), Akt inhibitor, PD 98059 (MEK inhibitor). It was also observed that L-leucine-induced increases of cyclin/CDK expression were inhibited by PI3K siRNA and ERK siRNA; L-leucine increased extracellular signal-regulated kinases 1/2 (ERK1/2) and Akt phosphorylation levels. Bisindolylmaleimide I attenuated L-leucine-induced phosphorylation of ERK1/2 but did not influence Akt phosphorylation, and PI3K siRNA and LY 294002 inhibited L-leucine-induced ERK1/2 phosphorylation, suggesting some cross-talk between the PKC and ERK1/2 or PI3K/Akt and ERK1/2 pathways. L-Leucine also increased the levels of phosphorylated molecular target of rapamycin (mTOR) and two of its targets, ribosomal protein S6 kinase (p70S6K), and 4E binding protein 1 (4E-BP1); furthermore, rapamycin (an mTOR inhibitor) blocked all of the mitogenic effects of L-leucine. In addition, Akt inhibitor blocked L-leucine-induced mTOR phosphorylation. In conclusion, L-leucine stimulated DNA synthesis and promoted cell cycle progression in primary cultured chicken hepatocytes through PKC, ERK1/2, PI3K/Akt, and mTOR.     

Activation of multiple signaling pathways is critical for fibroblast growth factor 2- and vascular endothelial growth factor-stimulated ovine fetoplacental endothelial cell proliferation

Fibroblast growth factor-2 (FGF2) and vascular endothelial growth factor (VEGF) are two key regulators of placental angiogenesis. The potent vasodilator nitric oxide (NO) could also act as a key mediator of FGF2- and VEGF-induced angiogenesis. However, the postreceptor signaling pathways governing these FGF2- and VEGF-induced placental angiogenic responses are poorly understood. In this study, we assessed the role of endogenous NO, mitogen-activated protein kinase 3/1 (MAPK3/1), and v-akt murine thymoma viral oncogene homolog 1 (AKT1) in FGF2- and VEGF-stimulated proliferation of ovine fetoplacental endothelial (OFPAE) cells. Both FGF2 and VEGF time-dependently stimulated (P < 0.05) NO production and activated AKT1. Both FGF2- and VEGF-stimulated cell proliferation was dose-dependently inhibited (P < 0.05) by N(G)-monomethyl-L-arginine (L-NMMA; an NO synthase inhibitor), PD98059 (a selective MAPK3/1 kinase 1 and 2 [MAP2K1/2] inhibitor), or LY294002 (a selective phosphatidylinositol 3 kinase [PI3K] inhibitor) but not by phenyl-4,4,5,5 tetramethylimidazoline-1-oxyl 3-oxide (PTIO, a potent extracellular NO scavenger). At the maximal inhibitory dose without cytotoxicity, PD98059 and LY294002 completely inhibited VEGF-induced cell proliferation but only partially attenuated (P < 0.05) FGF2-induced cell proliferation. PD98059 and LY294002 also inhibited (P < 0.05) FGF2- and VEGF-induced phosphorylation of MAPK3/1 and AKT1, respectively. L-NMMA did not significantly affect FGF2- and VEGF-induced phosphorylation of either MAPK3/1 or AKT1. Thus, in OFPAE cells, both FGF2- and VEGF-stimulated cell proliferation is partly mediated via NO as an intracellular and downstream signal of MAPK3/1 and AKT1 activation. Moreover, activation of both MAP2K1/2/MAPK3/1 and PI3K/AKT1 pathways is critical for FGF2-stimulated cell proliferation, whereas activation of either one pathway is sufficient for mediating the VEGF-induced maximal cell proliferation, indicating that these two kinase pathways differentially mediate the FGF2- and VEGF-stimulated OFPAE cell proliferation.     

GDNF and insulin cooperate to enhance the proliferation and differentiation of enteric crest‐derived cells

Previously we have shown that glial derived neurotrophic factor (GDNF) stimulates modest increases in the proliferation of avian enteric crest‐derived cells and similar increases in the phosphorylation of the phosphoinositide 3–kinase (PI3K) downstream substrate Akt (Akt‐P). In the present study we tested whether GDNF‐independent increases in PI3K activation would be sufficient to support proliferation. We found that insulin induces a large increase in the phosphorylation of Akt and can initiate DNA synthesis in avian enteric crest‐derived cells, but is unable to maintain proliferation over time in culture, measured by BrdU incorporation. GDNF can also initiate DNA synthesis, but it too is unable to maintain BrdU incorporation in cultured enteric crest‐derived cells. Sustained incorporation of BrdU after 16–48 h in culture is shown to be dependent on a combination of GDNF and insulin. Using a phospho‐specific antibody, we found Akt‐P levels to be similar in the proliferating (BrdU incorporation maintained from 16–48 h in culture) and nonproliferating populations, suggesting that Akt‐P levels were not solely controlling the extent of BrdU incorporation. A minimum level of PI3K activation, however, is required, as shown by the dose‐dependent reduction in proliferation with the PI3K inhibitor LY‐294002. We conclude that the integrity of the PI3K pathway is essential for enteric crest‐derived cell proliferation, but that the absolute levels of Akt‐P do not determine the extent of proliferation. The enhanced proliferation in cultures containing both GDNF and insulin suggests that other pathways are involved, including the possibility that PI3K downstream effectors other than Akt are important in the regulation of avian enteric crest‐derived cell proliferation. © 2003 Wiley Periodicals, Inc. J Neurobiol 55: 151–164, 2003     

The role of focal adhesion kinase-phosphatidylinositol 3-kinase-akt signaling in hepatic stellate cell proliferation and type I collagen expression

Following a fibrogenic stimulus, the hepatic stellate cell (HSC) undergoes a complex activation process associated with increased cell proliferation and excess deposition of type I collagen. The focal adhesion kinase (FAK)-phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway is activated by platelet-derived growth factor (PDGF) in several cell types. We investigated the role of the FAK-PI3K-Akt pathway in HSC activation. Inhibition of FAK activity blocked HSC migration, cell attachment, and PDGF-induced PI3K and Akt activation. Both serum- and PDGF-induced Akt phosphorylation was inhibited by LY294002, an inhibitor of PI3K. A constitutively active form of Akt stimulated HSC proliferation in serum-starved HSCs, whereas LY294002 and dominant-negative forms of Akt and FAK inhibited PDGF-induced proliferation. Transforming growth factor-beta, an inhibitor of HSC proliferation, did not block PDGF-induced Akt phosphorylation, suggesting that transforming growth factor-beta mediates its antiproliferative effect downstream of Akt. Expression of type I collagen protein and alpha1(I) collagen mRNA was increased by Akt activation and inhibited when PI3K activity was blocked. Therefore, FAK is important for HSC migration, cell attachment, and PDGF-induced cell proliferation. PI3K is positioned downstream of FAK. Signals for HSC proliferation are transduced through FAK, PI3K, and Akt. Finally, expression of type I collagen is regulated by the PI3K-Akt signaling pathway.     

The Increase in Retinal Cells Proliferation Induced by FGF2 is Mediated by Tyrosine and PI3 Kinases

Since 1973, multiple effects of basic fibroblast growth factor have been described in a large number of cells. These effects include proliferation, survival and differentiation. The aim of this work was to study the intracellular pathways involved in the basic fibroblast growth factor (FGF2) effect on rat retinal cells proliferation in vitro. Our data show that treatment with FGF2 increases proliferation in a concentration- and time-dependent manner. The effect of 25 ng/ml FGF2 was blocked by 10 μM genistein, a tyrosine kinase inhibitor and by 25 μM LY294002, a PI3 kinase inhibitor. The concomitant treatment with 0.3 μM chelerythrine chloride, a protein kinase C inhibitor, and 6.25 μM LY294002 also inhibited the effect of FGF2. Our results suggest that the proliferative effect of FGF2 on retinal cell cultures involves the activation of distinct kinases.     

PI3K信号通路通过Skp2、p27调节肝癌细胞的增殖

探讨磷脂酰肌醇3-激酶(PI3K)信号通路调节肝癌细胞增殖的机制.用LY294002特异性阻断PI3K信号通路后,人肝癌细胞(SMMC-7721)的增殖明显被抑制.RT-PCR及蛋白质印迹结果显示,LY294002增加了p27蛋白的表达,但不影响p27的mRNA表达.在LY294002处理的细胞中转入p27的RNAi质粒以干扰p27蛋白的表达后,肝癌细胞的增殖能力可部分恢复.放线菌酮(Chx)处理实验表明,阻断PI3K信号通路使p27蛋白的半衰期延长,稳定性增加.进一步研究发现,LY294002可抑制介导p27蛋白降解的关键分子Skp2的mRNA表达,还可缩短Skp2蛋白的半衰期,降低Skp2蛋白的稳定性.但在SMMC-7721中分别转染PI3K下游重要靶分子Akt的持续激活和失活突变体,却并不影响p27蛋白的表达.这些结果表明,PI3K信号通路在转录及翻译后水平调节Skp2的表达而影响p27蛋白的降解,从而调节肝癌细胞的增殖,但Akt并没有参与这种调节.     

IGF-I-induced oligodendrocyte progenitor proliferation requires PI3K/Akt, MEK/ERK, and Src-like tyrosine kinases

Insulin-like growth factor-I (IGF-I) is required for the growth of oligodendrocytes, although the underlying mechanisms are not fully understood. Our aim was to investigate the role of phosphatidylinositol 3-kinase (PI3K), mitogen-activated protein kinase kinase (MEK1), and Src family tyrosine kinases in IGF-I-stimulated proliferation of oligodendrocyte progenitors. IGF-I treatment increased the proliferation of cultured oligodendrocyte progenitors as determined by measuring incorporation of [(3)H]-thymidine and bromodeoxy-uridine (BrdU). IGF-I stimulated a transient phosphorylation of 3-phosphoinositide-dependent kinase-1 (PDK1) and extracellular signal-regulated kinases (ERK1/2) (targets of MEK1), as well as a rapid and sustained activation of Akt (a target of PI3K). Furthermore, inhibitors of PI3K (LY294002 and Wortmannin), MEK1 (PD98059 and U0126), and Src family tyrosine kinases (PP2) decreased IGF-I-induced proliferation, and blocked ERK1/2 activation. LY294002, Wortmannin and PP2 also blocked Akt activation. To further determine whether Akt is required for IGF-I stimulated oligodendrocyte progenitor proliferation, cultures were infected with adenovirus vectors expressing dominant-negative mutants of Akt or treated with pharmacological inhibitors of Akt. All treatments reduced IGF-I-induced oligodendrocyte progenitor proliferation. Our data indicate that stimulation of oligodendrocyte progenitor proliferation by IGF-I requires Src-like tyrosine kinases as well as the PI3K/Akt and MEK1/ERK signaling pathways.     

Follistatin could promote the proliferation of duck primary myoblasts by activating PI3K/Akt/mTOR signalling

FST (follistatin) is essential for skeletal muscle development, but the intracellular signalling networks that regulate FST-induced effects are not well defined. We sought to investigate whether FST promotes the proliferation of myoblasts through the PI3K (phosphoinositide 3-kinase)/Akt (protein kinase B)/mTOR (mammalian target of rapamycin) signalling. In the present study, we transfected the pEGFP-duFST plasmid and added PI3K and mTOR inhibitors to the medium of duck primary myoblasts. Then, we analysed the cellular phenotypic changes that occurred and analysed the expression of target genes. The results showed that FST promoted myoblast proliferation, induced the mRNA expression of PI3K, Akt, mTOR, 70-kDa ribosomal protein S6K (S6 kinase) and the protein expression of phospho-Akt (Thr³⁰⁸), mTOR, phospho-mTOR (serine 2448), phospho-S6K (Ser⁴¹⁷), inhibited the mRNA expression of FoxO1, MuRF1 (muscle RING finger-1) and the protein expression of phospho-FoxO1 (Ser²⁵⁶). Moreover, we found that the overexpression of FST could alleviate the inhibitory effect of myoblast proliferation caused by the addition of {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002, a PI3K inhibitor. Additionally, the overexpression of duck FST also relieved the inhibition of myoblast proliferation caused by the addition of rapamycin (an mTOR inhibitor) through PI3K/Akt/mTOR signalling. In light of the present results, we hypothesize that duck FST could promote myoblast proliferation, which is dependent on PI3K/Akt/mTOR signalling.     

Retinoic acid promotes proliferation of chicken primordial germ cells via activation of PI3K/Akt-mediated NF-κB signalling cascade

As embryonic progenitors for the gametes, PGCs (primordial germ cells) proliferate and develop under strict regulation of numerous intrinsic and external factors. As the most active natural metabolite of vitamin A, all-trans RA (retinoic acid) plays pivotal roles in regulating development of various cells. The proliferating action of RA on PGCs was investigated along with the intracellular PI3K (phosphoinositide 3-kinase)/Akt (protein kinase B; also known as Akt)-mediated NF-κB (nuclear factor κB) signalling cascade. The results show that RA significantly promoted PGC proliferation in a dose- and time-dependent manner, confirmed by BrdU (bromodeoxyuridine) incorporation and cell cycle analysis. However, this promoting effect was attenuated by sequential inhibitors of LY294002 for PI3K, KP372-1 for Akt and SN50 for NF-κB respectively. Western blot analysis showed increased Akt phosphorylation (Ser473) of PGCs after stimulation with RA, but this was abolished by LY294002 or KP372-1. Treatment with RA increased expression of NF-κB and decreased IκBα (inhibitory κBα) expression, which were inhibited by SN50. Blockade of PI3K or Akt activity inhibited NF-κB translocation from the cytoplasm to the nucleus. Finally, mRNA expression of cell cycle regulating genes [cyclin D1 and E, CDK6 (cyclin-dependent kinase 6) and CDK2] was up-regulated in the RA-treated cells. This stimulation was also markedly retarded by combined treatment with LY294002, KP372-1 and SN50. These results suggest that RA activates the PI3K/Akt and NF-κB signalling cascade to promote proliferation of the cultured chicken PGCs.     

Activation of phosphoinositide 3-kinase in response to inflammation and nitric oxide leads to the up-regulation of cyclooxygenase-2 expression and subsequent cell proliferation in mesangial cells

In this study, we showed that nitric oxide (NO) donors induced the mesangial cell proliferation and cyclooxygenase-2 (COX-2) protein expression in murine mesangial cells. An inflammatory condition [lipopolysaccharide (LPS) plus interferon-gamma (IFN-gamma)] could also induce cell proliferation and significantly enhance inducible nitric oxide synthase (iNOS) and COX-2 expression. Phosphoinositide 3-kinase (PI3K) inhibitor, LY294002, inhibited these responses. LPS/IFN-gamma-induced COX-2 expression in mesangial cells could be inhibited by iNOS inhibitor, aminoguanidine. Selective COX-2 inhibitor, NS398, was capable of inhibiting NO donor- or LPS/IFN-gamma-induced mesangial cell proliferation. Both NO donor and LPS/IFN-gamma markedly activated the PI3K activity and the phosphorylation of Akt and nuclear factor (NF)-kappaB DNA binding activity in mesangial cells, which could be inhibited by LY294002 and transfection of dominant-negative vectors of PI3K/p85 and Akt. These results indicate that a PI3K/Akt-dependent pathway involved in the NO-regulated COX-2 expression and cell proliferation in mesangial cells under inflammatory condition.     

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 3β (GSK3β), 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 GSK3β. All together, our data suggest that blocking the PI3K/Akt survival pathway sensitizes the curcumin-induced apoptosis in MCF-7 cells.