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Interferon-α enhances the susceptibility of renal cell carcinoma to rapamycin by suppressing mTOR activity.

Han X, Shang D, Han T, Xu X, Tian Y - Exp Ther Med (2014)

Bottom Line: The observations indicated that IFN-α significantly increased the susceptibility of RCC cells to RPM and the synergistic effect of IFN-α and RPM against RCC cells was confirmed in all three RCC cell lines.The mTOR pathway was shown to be associated with the synergistic effect of IFN-α and RPM against RCC.Therefore, the results of the present study indicate that the mTOR pathway plays an important role in the synergistic effect of IFN-α and RPM against RCC cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P.R. China.

ABSTRACT
The aim of the present study was to investigate the antiproliferative effects of interferon (IFN)-α and rapamycin (RPM) on renal cell carcinoma (RCC) cells and examine the synergistic growth suppression conferred by IFN-α and RPM. The effects of IFN-α and/or RPM on RCC cells were determined using a WST-1 assay and the synergy of IFN-α and RPM against three RCC cell lines was analyzed with isobolographic analysis. The expression of mammalian target of rapamycin (mTOR) was downregulated by RNAi, and the expression and phosphorylation of proteins in the mTOR pathway following treatment with IFN-α and/or RPM was examined by western blot analysis. The observations indicated that IFN-α significantly increased the susceptibility of RCC cells to RPM and the synergistic effect of IFN-α and RPM against RCC cells was confirmed in all three RCC cell lines. The mTOR pathway was shown to be associated with the synergistic effect of IFN-α and RPM against RCC. IFN-α and RPM alone decreased the phosphorylation of mTOR, p70 S6 kinase, S6 and 4E binding protein 1, and IFN-α significantly enhanced the RPM-induced suppression of the mTOR pathway. However, in RCC cells with low mTOR activity, the synergy of IFN-α and RPM was eliminated. Therefore, the results of the present study indicate that the mTOR pathway plays an important role in the synergistic effect of IFN-α and RPM against RCC cells. Thus, mTOR may serve as an effective therapeutic target in the treatment of advanced RCC.

No MeSH data available.


Related in: MedlinePlus

Effect of VHL activity on the synergy of IFN-α and RPM. VHL expression of VHL was downregulated in ACHN cells by RNAi and upregulated in A498 cells by transfection with a VHL vector, as confirmed by (A) western blot analysis and (B) RT-PCR. Isobolographic analysis demonstrated the effect of combination therapy with IFN-α and RPM on (C) A498 and (D) ACHN RCC cell lines. VHL, Von Hippel-Lindau; IFN, interferon; RPM, rapamycin; HIF, hypoxia-inducible transcription factor; RT-PCR, reverse transcription polymerase chain reaction; RCC, renal cell carcinoma.
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f4-etm-08-01-0267: Effect of VHL activity on the synergy of IFN-α and RPM. VHL expression of VHL was downregulated in ACHN cells by RNAi and upregulated in A498 cells by transfection with a VHL vector, as confirmed by (A) western blot analysis and (B) RT-PCR. Isobolographic analysis demonstrated the effect of combination therapy with IFN-α and RPM on (C) A498 and (D) ACHN RCC cell lines. VHL, Von Hippel-Lindau; IFN, interferon; RPM, rapamycin; HIF, hypoxia-inducible transcription factor; RT-PCR, reverse transcription polymerase chain reaction; RCC, renal cell carcinoma.

Mentions: The effect of VHL activity on the synergy of IFN-α and RPM against RCC was also investigated. VHL expression was downregulated in ACHN cells via RNAi and upregulated in A498 cells by transfection with a VHL vector. VHL/HIF expression was confirmed by western blot analysis and RT-PCR (Fig. 4A and B). Since VHL mediates HIF levels via a post-translational mechanism, VHL did not alter the mRNA expression levels of HIF-1α or -2α. Therefore, the results indicate that regardless of VHL activity, IFN-α enhances the susceptibility of RCC to RPM in all RCC cells tested in the study (Fig. 4C and D). Thus, the synergy of IFN-α and RPM does not depend on VHL activity in RCC cells.


Interferon-α enhances the susceptibility of renal cell carcinoma to rapamycin by suppressing mTOR activity.

Han X, Shang D, Han T, Xu X, Tian Y - Exp Ther Med (2014)

Effect of VHL activity on the synergy of IFN-α and RPM. VHL expression of VHL was downregulated in ACHN cells by RNAi and upregulated in A498 cells by transfection with a VHL vector, as confirmed by (A) western blot analysis and (B) RT-PCR. Isobolographic analysis demonstrated the effect of combination therapy with IFN-α and RPM on (C) A498 and (D) ACHN RCC cell lines. VHL, Von Hippel-Lindau; IFN, interferon; RPM, rapamycin; HIF, hypoxia-inducible transcription factor; RT-PCR, reverse transcription polymerase chain reaction; RCC, renal cell carcinoma.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4061221&req=5

f4-etm-08-01-0267: Effect of VHL activity on the synergy of IFN-α and RPM. VHL expression of VHL was downregulated in ACHN cells by RNAi and upregulated in A498 cells by transfection with a VHL vector, as confirmed by (A) western blot analysis and (B) RT-PCR. Isobolographic analysis demonstrated the effect of combination therapy with IFN-α and RPM on (C) A498 and (D) ACHN RCC cell lines. VHL, Von Hippel-Lindau; IFN, interferon; RPM, rapamycin; HIF, hypoxia-inducible transcription factor; RT-PCR, reverse transcription polymerase chain reaction; RCC, renal cell carcinoma.
Mentions: The effect of VHL activity on the synergy of IFN-α and RPM against RCC was also investigated. VHL expression was downregulated in ACHN cells via RNAi and upregulated in A498 cells by transfection with a VHL vector. VHL/HIF expression was confirmed by western blot analysis and RT-PCR (Fig. 4A and B). Since VHL mediates HIF levels via a post-translational mechanism, VHL did not alter the mRNA expression levels of HIF-1α or -2α. Therefore, the results indicate that regardless of VHL activity, IFN-α enhances the susceptibility of RCC to RPM in all RCC cells tested in the study (Fig. 4C and D). Thus, the synergy of IFN-α and RPM does not depend on VHL activity in RCC cells.

Bottom Line: The observations indicated that IFN-α significantly increased the susceptibility of RCC cells to RPM and the synergistic effect of IFN-α and RPM against RCC cells was confirmed in all three RCC cell lines.The mTOR pathway was shown to be associated with the synergistic effect of IFN-α and RPM against RCC.Therefore, the results of the present study indicate that the mTOR pathway plays an important role in the synergistic effect of IFN-α and RPM against RCC cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P.R. China.

ABSTRACT
The aim of the present study was to investigate the antiproliferative effects of interferon (IFN)-α and rapamycin (RPM) on renal cell carcinoma (RCC) cells and examine the synergistic growth suppression conferred by IFN-α and RPM. The effects of IFN-α and/or RPM on RCC cells were determined using a WST-1 assay and the synergy of IFN-α and RPM against three RCC cell lines was analyzed with isobolographic analysis. The expression of mammalian target of rapamycin (mTOR) was downregulated by RNAi, and the expression and phosphorylation of proteins in the mTOR pathway following treatment with IFN-α and/or RPM was examined by western blot analysis. The observations indicated that IFN-α significantly increased the susceptibility of RCC cells to RPM and the synergistic effect of IFN-α and RPM against RCC cells was confirmed in all three RCC cell lines. The mTOR pathway was shown to be associated with the synergistic effect of IFN-α and RPM against RCC. IFN-α and RPM alone decreased the phosphorylation of mTOR, p70 S6 kinase, S6 and 4E binding protein 1, and IFN-α significantly enhanced the RPM-induced suppression of the mTOR pathway. However, in RCC cells with low mTOR activity, the synergy of IFN-α and RPM was eliminated. Therefore, the results of the present study indicate that the mTOR pathway plays an important role in the synergistic effect of IFN-α and RPM against RCC cells. Thus, mTOR may serve as an effective therapeutic target in the treatment of advanced RCC.

No MeSH data available.


Related in: MedlinePlus