Suppression Of Akt Signaling Pathways Research Articles

Structural modification of resveratrol analogue exhibits anticancer activity against lung cancer stem cells via suppression of Akt signaling pathway

BackgroundCompound with cancer stem cell (CSC)-suppressing activity is promising for the improvement of lung cancer clinical outcomes. Toward this goal, we discovered the CSC-targeting activity of resveratrol (RES) analog moscatilin (MOS). With slight structural modification from RES, MOS shows dominant cytotoxicity and CSC-suppressive effect.MethodsThree human lung cancer cell lines, namely H23, H292, and A549, were used to compare the effects of RES and MOS. Cell viability and apoptosis were determined by the MTT assay and Hoechst33342/PI double staining. Anti-proliferative activity was determined by colony formation assay and cell cycle analysis. Intracellular reactive oxygen species (ROS) were measured by fluorescence microscopy using DCFH2-DA staining. CSC-rich populations of A549 cells were generated, and CSC markers, and Akt signaling were determined by Western blot analysis and immunofluorescence. Molecular docking and molecular dynamics (MD) simulations were used to predict the possible binding of the compound to Akt protein.ResultsIn this study, we evaluated the effects of RES and MOS on lung cancer and its anti-CSC potential. Compared with RES, its analog MOS more effectively inhibited cell viability, colony formation, and induced apoptosis in all lung cancer cell lines (H23, H292, and A549). We further investigated the anti-CSC effects on A549 CSC-rich populations and cancer adherent cells (A549 and H23). MOS possesses the ability to suppress CSC-like phenotype of lung cancer cells more potent than RES. Both MOS and RES repressed lung CSCs by inhibiting the viability, proliferation, and lung CSC-related marker CD133. However, only MOS inhibits the CSC marker CD133 in both CSC-rich population and adherent cells. Mechanistically, MOS exerted its anti-CSC effects by inhibiting Akt and consequently restored the activation of glycogen synthase kinase 3β (GSK-3β) and decreased the pluripotent transcription factors (Sox2 and c-Myc). Thus, MOS inhibits CSC-like properties through the repression of the Akt/GSK-3β/c-Myc pathway. Moreover, the superior inhibitory effects of MOS compared to RES were associated with the improved activation of various mechanism, such as cell cycle arrest at G2/M phase, production of ROS-mediated apoptosis, and inhibition of Akt activation. Notably, the computational analysis confirmed the strong interaction between MOS and Akt protein. MD simulations revealed that the binding between MOS and Akt1 was more stable than RES, with MM/GBSA binding free energy of − 32.8245 kcal/mol at its allosteric site. In addition, MOS interacts with Trp80 and Tyr272, which was a key residue in allosteric inhibitor binding and can potentially alter Akt activity.ConclusionsKnowledge about the effect of MOS as a CSC-targeting compound and its interaction with Akt is important for the development of drugs for the treatment of CSC-driven cancer including lung cancer.

Brassicasterol inhibits hepatitis B virus-associated hepatocellular carcinoma development via suppression of AKT signaling pathway

BackgroundHepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) does not respond well to current treatment options like sorafenib, and there is an urgent need for developing therapeutical strategies for HBV + HCC. Brassicasterol has previously shown anti-cancer and anti-viral activities, however, its value against HBV + HCC remains to be explored.MethodsThe inhibitory effect of brassicasterol and sorafenib was evaluated on HBV + HCC cell lines and xenograft mouse model. The cytotoxicity of brassicasterol on normal liver cells were measured by LDH assay. AKT agonist was used to identify the targeted signaling pathway by brassicasterol.ResultsBrassicasterol induced HBV + HCC cell death in a both dose-dependent and time-dependent manner, and such inhibition was more potent than sorafenib. Brassicasterol did not show apparent cytotoxicity to normal liver cells. Xenograft mouse model further confirmed the inhibitory effect of brassicasterol on the growth of HBV + HCC. Furthermore, signaling pathway analysis showed that brassicasterol-treated HBV + HCC cells had decreased level of phosphor-AKT expression while the addition of AKT agonist could counteract the inhibitory effect of brassicasterol on HCC, indicating that brassicasterol suppressed AKT pathway to exhibit anti-cancer activity in HBV + HCC cells. In addition, brassicasterol showed similar levels of inhibition on HBV− and HBV + HCC cells.ConclusionBrassicasterol possesses anti-cancer activity against HCC through the downregulation of AKT pathway and such activity is independent of HBV infection.

Silencing of lncRNA UCA1 inhibited the pathological progression in PCOS mice through the regulation of PI3K/AKT signaling pathway

BackgroundPolycystic ovary syndrome (PCOS) is the most common hormonal disorder among reproductive-aged women worldwide, however, the mechanisms and progression of PCOS still unclear due to its heterogeneous nature. Using the human granulosa-like tumor cell line (KGN) and PCOS mice model, we explored the function of lncRNA UCA1 in the pathological progression of PCOS.ResultsCCK8 assay and Flow cytometry were used to do the cell cycle, apoptosis and proliferation analysis, the results showed that UCA1 knockdown in KGN cells inhibited cell proliferation by blocking cell cycle progression and promoted cell apoptosis. In the in vivo experiment, the ovary of PCOS mice was injected with lentivirus carrying sh-UCA1, the results showed that knockdown of lncRNA UCA1 attenuated the ovary structural damage, increased the number of granular cells, inhibited serum insulin and testosterone release, and reduced the pro-inflammatory cytokine production. Western blot also revealed that UCA1 knockdown in PCOS mice repressed AKT activation, inhibitor experiment demonstrated that suppression of AKT signaling pathway, inhibited the cell proliferation and promoted apoptosis.ConclusionsOur study revealed that, in vitro, UCA1 knockdown influenced the apoptosis and proliferation of KGN cells, in vivo, silencing of UCA1 regulated the ovary structural damage, serum insulin release, pro-inflammatory production, and AKT signaling pathway activation, suggesting lncRNA UCA1 plays an important role in the pathological progression of PCOS.

Gambogic acid induces cell apoptosis through endoplasmic reticulum stress triggered inhibition of Akt signaling pathways in extranodal NK/T-cell lymphoma cells

As the chemotherapeutic resistance of extranodal NK/T-cell lymphoma (ENKTL) rises year by year, searching for novel chemoprevention compounds has become imminent. Gambogic acid (GA) has recently been shown to have anti-tumor effects, but its role and underling mechanism in ENKTL are rather elusive. In the present study, we showed that GA inhibited the cell growth and potently induced the apoptosis of ENKTL cells in vitro in a time- and concentration-dependent manner. Furthermore, GA induced cell death through endoplasmic reticulum stress (ERS) mediated suppression of Akt signaling pathways and finally the release of the caspase-3 proteases. Overall, our data provided evidences supporting GA as a potential therapeutic agent for ENKTL, which may facilitate further preclinical development of anti-tumor drugs.

Structural characterization of a polysaccharide from the flower buds of Tussilago farfara, and its effect on proliferation and apoptosis of A549 human non-small lung cancer cell line

In present study, we purified a polysaccharide, TFPB1, from the flower buds of Tussilago farfara using DEAE-cellulose 52 anion-exchange and Sephacryl S-300 HR gel filtration chromatography. TFPB1 was a homogeneous polysaccharide with a molecular weight of 37.8kDa and composed of rhamnose, galacturonic acid, glucose, galactose, and arabinose, in a ratio of 13:13:1:7:12. Methylation and NMR results demonstrated that TFPB1 contained a rhamnogalacturonan I backbone consisting of a repeat disaccharide unit →4)-α-D-GalAp-(1→2)-α-L-Rhap-(1→, substituted by various type II arabinogalactan branches including terminal galactose, (1→3)-β-D-galactan and (1→5)-α-L-arabinan, attached to the O-4 of (1→2)-α-L-Rhap. TFPB1 was found to inhibit cell proliferation of A549 cells and induce cell apoptosis in vitro. Furthermore, TFPB1 downregulated the phosphorylation of Akt, and upregulated caspase-3, Fas, FasL, and Bax expression, but downregulated Bcl-2 expression. Therefore, TFPB1 exhibited anti-proliferative and anti-apoptotic effect partly depending on the suppression of Akt signaling pathway. These findings provided us a potential chemotherapeutic strategy for the treatment of human non-small cell lung cancer.

Abstract 4552: Trimethoxy-cis-stilbene exhibits potent anti-tumor activities via suppression of AKT signaling and cell cycle arrest in virus-induced hepatocellular carcinoma

Abstract Background: Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world, and the incidence is likely to increase due to other health complications such as obesity and diabetes. Chronic hepatitis C virus (HCV) infection and cirrhosis are considered to be major risk factors for induction of HCC. HCV induces cirrhosis, regenerative nodules and cancer stem cell (CSC)-related proteins in the liver. Treatments for chronic hepatitis C and HCC have been challenging so far. Therefore, identification of novel therapeutic agents that target HCV and/or HCV-induced HCC is an unmet medical need. Resveratrol (RES) and its synthetic analogue, trimethoxy-cis-stilbene (TMS) have shown to possess a range of therapeutic activities against various diseases. Although RES has been extensively studied, the anti-viral and anti-tumor activities of TMS have not been fully explored. Methods: HCV subgenomic replicon-expressing hepatoma cells were treated with varying concentrations of RES, TMS or DMSO (control) for 48 hrs. The IC50 values for these drugs were determined based on HCV expression levels in the treated and untreated cultures. Effects of the drugs on cell cycle and AKT signaling pathways were investigated using flow cytometry and protein expression profiles. Cell cytotoxicity of the drugs was determined by MTS assay using normal human hepatocytes (NHH) and hepatoma cells. Magnetic levitation method was carried out to determine effects of the drugs on 3D spheroid cultures. Results: Both RES and TMS downregulated the HCV RNA and NS5B polymerase levels within 48 hr and showed IC50 values equivalent to 100 μM and 1.0 μM, respectively. However, the NHH viability was not compromised during these culture conditions as determined by cytotoxic assays. The anti-HCV effects were accompanied by cell cycle arrest at G2/M phase for TMS, whereas G1/S arrest was observed for RES. TMS-induced G2/M arrest was confirmed by a sharp reduction in phosphorylated CDK1 level in the treated cells. Further analysis showed that active serine/threonine kinase AKT (phosphorylated at Ser473) level was significantly reduced by 1.0 μM TMS. Conversely, the level of p21(Cip1/Waf1), a CDK1 inhibitor, was increased following TMS treatment. Only TMS, but not DMSO (control), successfully inhibited 3D hepatoma spheroid growth in culture. Conclusion: Trimethoxy-cis-stilbene appears to be more potent than its parent compound resveratrol as an anti-HCV and anti-tumor drug in culture conditions. Its anti-tumor effects on HCV-expressing hepatoma cells are exerted by suppression of AKT signaling pathway and cell cycle arrest. This is also supported by an increase in p21(Cip1/Waf1) levels following TMS treatment. Based on these observations, TMS appears to be a promising therapeutic agent for HCV-induced liver diseases including HCC. Citation Format: Charles Nguyen, Hari Kotturi, Sripathi Sureban, Randal J. May, Parthasarathy Chandrakesan, Nathaniel Weygant, Dongfeng Qu, Courtney Houchen, Naushad Ali. Trimethoxy-cis-stilbene exhibits potent anti-tumor activities via suppression of AKT signaling and cell cycle arrest in virus-induced hepatocellular carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4552. doi:10.1158/1538-7445.AM2014-4552