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Rapamycin Enhances the Anti-Cancer Effect of Dasatinib by Suppressing Src/PI3K/mTOR Pathway in NSCLC Cells.

Chen B, Xu X, Luo J, Wang H, Zhou S - PLoS ONE (2015)

Bottom Line: In this study, we found that Rapamycin dramatically enhanced Dasatinib-induced cell growth inhibition and cell cycle G1 arrest in human lung adenocarcinoma A549 cells without affecting apoptosis.The synergistic effects were consistently correlated with the up-regulation of cyclin-dependent kinases inhibitor proteins, including p16, p19, p21, and p27, as well as the repression of Cdk4 expression and nuclear translocation.Restraining Src and mTOR with small interfering RNA in A549 cells further confirmed that the Src/PI3K/mTOR Pathway played a crucial role in enhancing the anticancer effect of Dasatinib.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Oncology, Shanghai Pulmonary Hospital, Shanghai, China; School of Medicine Cancer Institute, Tongji University, Shanghai, China.

ABSTRACT
Src and the mammalian target of rapamycin (mTOR) signaling are commonly activated in non-small cell lung cancer (NSCLC) and hence potential targets for chemotherapy. Although the combined use of Src inhibitor Dasatinib with other chemotherapeutic agents has shown superior efficacy for cancer treatment, the mechanisms that lead to enhanced sensitivity of Dasatinib are not completely understood. In this study, we found that Rapamycin dramatically enhanced Dasatinib-induced cell growth inhibition and cell cycle G1 arrest in human lung adenocarcinoma A549 cells without affecting apoptosis. The synergistic effects were consistently correlated with the up-regulation of cyclin-dependent kinases inhibitor proteins, including p16, p19, p21, and p27, as well as the repression of Cdk4 expression and nuclear translocation. Mechanistic investigations demonstrated that FoxO1/FoxO3a and p70S6K/4E-BP1, the molecules at downstream of Src-PI3K-Akt and mTOR signaling, were significantly suppressed by the combined use of Dasatinib and Rapamycin. Restraining Src and mTOR with small interfering RNA in A549 cells further confirmed that the Src/PI3K/mTOR Pathway played a crucial role in enhancing the anticancer effect of Dasatinib. In addition, this finding was also validated by a series of assays using another two NSCLC cell lines, NCI-H1706 and NCI-H460. Conclusively, our results suggested that the combinatory application of Src and mTOR inhibitors might be a promising therapeutic strategy for NSCLC treatment.

No MeSH data available.


Related in: MedlinePlus

Rapamycin potentiated Dasatinib to up-regulate CDK inhibitor proteins and thereby down-regulate Cdk4.A549 cells were treated with vehicle control (0.1% DMSO) or Dasatinib (10 nM) in the presence and absence of Rapamycin (100 nM) for 24 h. (A) Relative expression of CDK inhibitor proteins (p16, p19, p21 and p27) at mRNA level. Columns, mean of three determinations; bars, SD. * p < 0.05, ** p < 0.01. (B) Expression of CDK inhibitor proteins, CDKs and FoxOs determined by western blotting. (D) Localization of Cdk4 determined by immunofluorescence staining. Representative pictures indicated staining of Cdk4 (red), nucleus (blue), and the merged images.
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pone.0129663.g002: Rapamycin potentiated Dasatinib to up-regulate CDK inhibitor proteins and thereby down-regulate Cdk4.A549 cells were treated with vehicle control (0.1% DMSO) or Dasatinib (10 nM) in the presence and absence of Rapamycin (100 nM) for 24 h. (A) Relative expression of CDK inhibitor proteins (p16, p19, p21 and p27) at mRNA level. Columns, mean of three determinations; bars, SD. * p < 0.05, ** p < 0.01. (B) Expression of CDK inhibitor proteins, CDKs and FoxOs determined by western blotting. (D) Localization of Cdk4 determined by immunofluorescence staining. Representative pictures indicated staining of Cdk4 (red), nucleus (blue), and the merged images.

Mentions: G1 cell cycle arrest is controlled by multiple factors including cyclins, cell division cycle protein (Cdc), CDKs and CDK inhibitor proteins. Our preliminary study demonstrated that the expressions of Cyclin A/D1/E and Cdc25A were not significantly changed by Dasatinib and Rapamycin at mRNA and protein levels (S1 Fig). As for CDK inhibitors, Dasatinib increased the expression of p16, p19, and p21 at both mRNA (Fig 2A) and protein (Fig 2B) levels, with statistical difference from the control groups. Interestingly, the co-treatment with Rapamycin markedly promoted Dasatinib-induced up-regulation of p16, p19, p21, and p27, but Rapamycin alone appeared to have little impact on the expression of these CDK inhibitor proteins. As the consequence, the expression of Cdk4 was dramatically suppressed by the combination of Dasatinib and Rapamycin, but neither Cdk2 nor Cdk6 seemed clearly responsive to the treatments (Fig 2B).


Rapamycin Enhances the Anti-Cancer Effect of Dasatinib by Suppressing Src/PI3K/mTOR Pathway in NSCLC Cells.

Chen B, Xu X, Luo J, Wang H, Zhou S - PLoS ONE (2015)

Rapamycin potentiated Dasatinib to up-regulate CDK inhibitor proteins and thereby down-regulate Cdk4.A549 cells were treated with vehicle control (0.1% DMSO) or Dasatinib (10 nM) in the presence and absence of Rapamycin (100 nM) for 24 h. (A) Relative expression of CDK inhibitor proteins (p16, p19, p21 and p27) at mRNA level. Columns, mean of three determinations; bars, SD. * p < 0.05, ** p < 0.01. (B) Expression of CDK inhibitor proteins, CDKs and FoxOs determined by western blotting. (D) Localization of Cdk4 determined by immunofluorescence staining. Representative pictures indicated staining of Cdk4 (red), nucleus (blue), and the merged images.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4465694&req=5

pone.0129663.g002: Rapamycin potentiated Dasatinib to up-regulate CDK inhibitor proteins and thereby down-regulate Cdk4.A549 cells were treated with vehicle control (0.1% DMSO) or Dasatinib (10 nM) in the presence and absence of Rapamycin (100 nM) for 24 h. (A) Relative expression of CDK inhibitor proteins (p16, p19, p21 and p27) at mRNA level. Columns, mean of three determinations; bars, SD. * p < 0.05, ** p < 0.01. (B) Expression of CDK inhibitor proteins, CDKs and FoxOs determined by western blotting. (D) Localization of Cdk4 determined by immunofluorescence staining. Representative pictures indicated staining of Cdk4 (red), nucleus (blue), and the merged images.
Mentions: G1 cell cycle arrest is controlled by multiple factors including cyclins, cell division cycle protein (Cdc), CDKs and CDK inhibitor proteins. Our preliminary study demonstrated that the expressions of Cyclin A/D1/E and Cdc25A were not significantly changed by Dasatinib and Rapamycin at mRNA and protein levels (S1 Fig). As for CDK inhibitors, Dasatinib increased the expression of p16, p19, and p21 at both mRNA (Fig 2A) and protein (Fig 2B) levels, with statistical difference from the control groups. Interestingly, the co-treatment with Rapamycin markedly promoted Dasatinib-induced up-regulation of p16, p19, p21, and p27, but Rapamycin alone appeared to have little impact on the expression of these CDK inhibitor proteins. As the consequence, the expression of Cdk4 was dramatically suppressed by the combination of Dasatinib and Rapamycin, but neither Cdk2 nor Cdk6 seemed clearly responsive to the treatments (Fig 2B).

Bottom Line: In this study, we found that Rapamycin dramatically enhanced Dasatinib-induced cell growth inhibition and cell cycle G1 arrest in human lung adenocarcinoma A549 cells without affecting apoptosis.The synergistic effects were consistently correlated with the up-regulation of cyclin-dependent kinases inhibitor proteins, including p16, p19, p21, and p27, as well as the repression of Cdk4 expression and nuclear translocation.Restraining Src and mTOR with small interfering RNA in A549 cells further confirmed that the Src/PI3K/mTOR Pathway played a crucial role in enhancing the anticancer effect of Dasatinib.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Oncology, Shanghai Pulmonary Hospital, Shanghai, China; School of Medicine Cancer Institute, Tongji University, Shanghai, China.

ABSTRACT
Src and the mammalian target of rapamycin (mTOR) signaling are commonly activated in non-small cell lung cancer (NSCLC) and hence potential targets for chemotherapy. Although the combined use of Src inhibitor Dasatinib with other chemotherapeutic agents has shown superior efficacy for cancer treatment, the mechanisms that lead to enhanced sensitivity of Dasatinib are not completely understood. In this study, we found that Rapamycin dramatically enhanced Dasatinib-induced cell growth inhibition and cell cycle G1 arrest in human lung adenocarcinoma A549 cells without affecting apoptosis. The synergistic effects were consistently correlated with the up-regulation of cyclin-dependent kinases inhibitor proteins, including p16, p19, p21, and p27, as well as the repression of Cdk4 expression and nuclear translocation. Mechanistic investigations demonstrated that FoxO1/FoxO3a and p70S6K/4E-BP1, the molecules at downstream of Src-PI3K-Akt and mTOR signaling, were significantly suppressed by the combined use of Dasatinib and Rapamycin. Restraining Src and mTOR with small interfering RNA in A549 cells further confirmed that the Src/PI3K/mTOR Pathway played a crucial role in enhancing the anticancer effect of Dasatinib. In addition, this finding was also validated by a series of assays using another two NSCLC cell lines, NCI-H1706 and NCI-H460. Conclusively, our results suggested that the combinatory application of Src and mTOR inhibitors might be a promising therapeutic strategy for NSCLC treatment.

No MeSH data available.


Related in: MedlinePlus