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The AKT inhibitor MK-2206 is cytotoxic in hepatocarcinoma cells displaying hyperphosphorylated AKT-1 and synergizes with conventional chemotherapy.

Simioni C, Martelli AM, Cani A, Cetin-Atalay R, McCubrey JA, Capitani S, Neri LM - Oncotarget (2013)

Bottom Line: The inhibitor decreased cell viability and induced cell cycle arrest in the G0/G1 phase of the cell cycle, with a higher efficacy in cells with hyperphosphorylated Akt-1.MK-2206 synergized with doxorubicin, a chemotherapeutic drug widely used for HCC treatment.Our findings suggest that the use of Akt inhibitors, either alone or in combination with doxorubicin, may be considered as an attractive therapeutic regimen for the treatment of HCC.

View Article: PubMed Central - PubMed

Affiliation: Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy.

ABSTRACT
Hepatocellular carcinoma (HCC) is one of the most common potentially lethal human malignancies worldwide. Advanced or recurrent HCC is frequently resistant to conventional chemotherapeutic agents and radiation. Therefore, targeted agents with tolerable toxicity are mandatory to improve HCC therapy and prognosis. In this neoplasia, the PI3K/Akt signaling network has been frequently shown to be aberrantly up-regulated. To evaluate whether Akt could represent a target for treatment of HCC, we studied the effects of the allosteric Akt inhibitor, MK-2206, on a panel of HCC cell lines characterized by different levels of Akt-1 activation. The inhibitor decreased cell viability and induced cell cycle arrest in the G0/G1 phase of the cell cycle, with a higher efficacy in cells with hyperphosphorylated Akt-1. Moreover, MK-2206 induced apoptosis, as documented by Annexin V labeling, and also caused autophagy, as evidenced by increased levels of the autophagy marker LC3A/B. Autophagy was shown to be a protective mechanism against MK-2206 cytotoxicity. MK-2206 down-regulated, in a concentration-dependent manner, the phosphorylation levels of Akt-1 and its downstream targets, GSK3 α/β and FOXO3A. MK-2206 synergized with doxorubicin, a chemotherapeutic drug widely used for HCC treatment. Our findings suggest that the use of Akt inhibitors, either alone or in combination with doxorubicin, may be considered as an attractive therapeutic regimen for the treatment of HCC.

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Down-regulation of Akt-1 reduces MK-2206 cytotoxicity in Mahlavu cells(A) Western blot analysis for Akt-1 in cells transfected for 24h with siRNA to Akt-1 and effects of MK-2206. LIPO: cells treated with Lipofectamine alone. β-actin served as a loading control. (B, C) xCELLigence System analysis documenting the effects of MK-2206 (18h of treatment) on cell growth, starting after 6h of transfection with siRNA to Akt-1. In (B) one representative of three different experiments is shown. In (C) the results are the mean ± s.d. of three different experiments. The asterisk indicate significant differences (p<0.05).
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Figure 5: Down-regulation of Akt-1 reduces MK-2206 cytotoxicity in Mahlavu cells(A) Western blot analysis for Akt-1 in cells transfected for 24h with siRNA to Akt-1 and effects of MK-2206. LIPO: cells treated with Lipofectamine alone. β-actin served as a loading control. (B, C) xCELLigence System analysis documenting the effects of MK-2206 (18h of treatment) on cell growth, starting after 6h of transfection with siRNA to Akt-1. In (B) one representative of three different experiments is shown. In (C) the results are the mean ± s.d. of three different experiments. The asterisk indicate significant differences (p<0.05).

Mentions: To further evaluate the inhibition of Akt-1 signaling as a major molecular target responsible for the effects of MK-2206 in HCC cells, we down-regulated protein expression of Akt-1 in Mahlavu cells by using siRNA. After 24h of transfection, we first examined by Western blotting the decrease of Akt-1 expression. As shown in Fig. 5A, Akt-1 siRNA significantly reduced the expression of Akt-1 protein. Down-regulation of Akt-1 was not further increased by administration of MK-2206.


The AKT inhibitor MK-2206 is cytotoxic in hepatocarcinoma cells displaying hyperphosphorylated AKT-1 and synergizes with conventional chemotherapy.

Simioni C, Martelli AM, Cani A, Cetin-Atalay R, McCubrey JA, Capitani S, Neri LM - Oncotarget (2013)

Down-regulation of Akt-1 reduces MK-2206 cytotoxicity in Mahlavu cells(A) Western blot analysis for Akt-1 in cells transfected for 24h with siRNA to Akt-1 and effects of MK-2206. LIPO: cells treated with Lipofectamine alone. β-actin served as a loading control. (B, C) xCELLigence System analysis documenting the effects of MK-2206 (18h of treatment) on cell growth, starting after 6h of transfection with siRNA to Akt-1. In (B) one representative of three different experiments is shown. In (C) the results are the mean ± s.d. of three different experiments. The asterisk indicate significant differences (p<0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3824526&req=5

Figure 5: Down-regulation of Akt-1 reduces MK-2206 cytotoxicity in Mahlavu cells(A) Western blot analysis for Akt-1 in cells transfected for 24h with siRNA to Akt-1 and effects of MK-2206. LIPO: cells treated with Lipofectamine alone. β-actin served as a loading control. (B, C) xCELLigence System analysis documenting the effects of MK-2206 (18h of treatment) on cell growth, starting after 6h of transfection with siRNA to Akt-1. In (B) one representative of three different experiments is shown. In (C) the results are the mean ± s.d. of three different experiments. The asterisk indicate significant differences (p<0.05).
Mentions: To further evaluate the inhibition of Akt-1 signaling as a major molecular target responsible for the effects of MK-2206 in HCC cells, we down-regulated protein expression of Akt-1 in Mahlavu cells by using siRNA. After 24h of transfection, we first examined by Western blotting the decrease of Akt-1 expression. As shown in Fig. 5A, Akt-1 siRNA significantly reduced the expression of Akt-1 protein. Down-regulation of Akt-1 was not further increased by administration of MK-2206.

Bottom Line: The inhibitor decreased cell viability and induced cell cycle arrest in the G0/G1 phase of the cell cycle, with a higher efficacy in cells with hyperphosphorylated Akt-1.MK-2206 synergized with doxorubicin, a chemotherapeutic drug widely used for HCC treatment.Our findings suggest that the use of Akt inhibitors, either alone or in combination with doxorubicin, may be considered as an attractive therapeutic regimen for the treatment of HCC.

View Article: PubMed Central - PubMed

Affiliation: Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy.

ABSTRACT
Hepatocellular carcinoma (HCC) is one of the most common potentially lethal human malignancies worldwide. Advanced or recurrent HCC is frequently resistant to conventional chemotherapeutic agents and radiation. Therefore, targeted agents with tolerable toxicity are mandatory to improve HCC therapy and prognosis. In this neoplasia, the PI3K/Akt signaling network has been frequently shown to be aberrantly up-regulated. To evaluate whether Akt could represent a target for treatment of HCC, we studied the effects of the allosteric Akt inhibitor, MK-2206, on a panel of HCC cell lines characterized by different levels of Akt-1 activation. The inhibitor decreased cell viability and induced cell cycle arrest in the G0/G1 phase of the cell cycle, with a higher efficacy in cells with hyperphosphorylated Akt-1. Moreover, MK-2206 induced apoptosis, as documented by Annexin V labeling, and also caused autophagy, as evidenced by increased levels of the autophagy marker LC3A/B. Autophagy was shown to be a protective mechanism against MK-2206 cytotoxicity. MK-2206 down-regulated, in a concentration-dependent manner, the phosphorylation levels of Akt-1 and its downstream targets, GSK3 α/β and FOXO3A. MK-2206 synergized with doxorubicin, a chemotherapeutic drug widely used for HCC treatment. Our findings suggest that the use of Akt inhibitors, either alone or in combination with doxorubicin, may be considered as an attractive therapeutic regimen for the treatment of HCC.

Show MeSH
Related in: MedlinePlus