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Translation initiation complex eIF4F is a therapeutic target for dual mTOR kinase inhibitors in non-Hodgkin lymphoma.

Demosthenous C, Han JJ, Stenson MJ, Maurer MJ, Wellik LE, Link B, Hege K, Dogan A, Sotomayor E, Witzig T, Gupta M - Oncotarget (2015)

Bottom Line: Treatment with the active-site dual mTOR inhibitor CC214-1 reduced the level of the eIF4F complex by decreasing the cap bound fraction of eIF4G and increasing the levels of 4E-BP1.Inhibition of eIF4E with shRNA further decreased the CC214-1 induced inhibition of the eIF4F complex, c-Myc, cyclin D3 translation, and colony formation.These studies demonstrate that the eIF4F complex is deregulated in aggressive lymphoma and that dual mTOR therapy has therapeutic potential in these patients.

View Article: PubMed Central - PubMed

Affiliation: Division of Hematology, Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA.

ABSTRACT
Deregulated mRNA translation has been implicated in disease development and in part is controlled by a eukaryotic initiation complex eIF4F (composed of eIF4E, eIF4G and eIF4A). We demonstrate here that the cap bound fraction from lymphoma cells was enriched with eIF4G and eIF4E indicating that lymphoma cells exist in an activated translational state. Moreover, 77% (110/142) of diffuse large B cell lymphoma tumors expressed eIF4E and this was associated with an inferior event free survival. Over-expression of wild-type eIF4E (eIF4E(WT)) but not cap-mutant eIF4E (eIF4E(cap mutant)) increased the activation of the eIF4F complex. Treatment with the active-site dual mTOR inhibitor CC214-1 reduced the level of the eIF4F complex by decreasing the cap bound fraction of eIF4G and increasing the levels of 4E-BP1. CC214-1 inhibited both the cap dependent and global protein translation. CC214-1 inhibited c-Myc, and cyclin D3 translation by decreasing polysomal fractions from lymphoma cells. Inhibition of eIF4E with shRNA further decreased the CC214-1 induced inhibition of the eIF4F complex, c-Myc, cyclin D3 translation, and colony formation. These studies demonstrate that the eIF4F complex is deregulated in aggressive lymphoma and that dual mTOR therapy has therapeutic potential in these patients.

No MeSH data available.


Related in: MedlinePlus

Effect of mTORC1/mTORC2 inhibitor CC214-1 on expression of eIF4E sensitive mRNAs(A) RT–PCR was performed in the CC214-1 treated Jeko and Granta cells using specific primers for cyclin D3, Mcl-1 and c-Myc. GADPH is shown as a loading control. The experiment was repeated 3 times. (B) Cyclin D3, Mcl-1 and c-Myc protein expression was assessed by western blotting in Jeko cells after treatment with various concentrations of CC214-1. (C) Cyclin D3, Mcl-1 and c-Myc protein expression was assessed in eIF4E shRNA stably transfected HEK293 cells in the presence and absence of CC214-1.
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Figure 4: Effect of mTORC1/mTORC2 inhibitor CC214-1 on expression of eIF4E sensitive mRNAs(A) RT–PCR was performed in the CC214-1 treated Jeko and Granta cells using specific primers for cyclin D3, Mcl-1 and c-Myc. GADPH is shown as a loading control. The experiment was repeated 3 times. (B) Cyclin D3, Mcl-1 and c-Myc protein expression was assessed by western blotting in Jeko cells after treatment with various concentrations of CC214-1. (C) Cyclin D3, Mcl-1 and c-Myc protein expression was assessed in eIF4E shRNA stably transfected HEK293 cells in the presence and absence of CC214-1.

Mentions: Long, highly structured 5′-UTRs are typical of proto-oncogene mRNAs such as c-Myc, Mcl-1 and Cyclin D3 and considered eIF4E sensitive.[3, 14] To evaluate the effects of treatment with CC214-1 on the transcription of eIF4E known targets, we performed qualitative RT-PCR using specific primers for cyclin D3, Mcl-1 and c-Myc. CC214-1 did not inhibit the transcription of cyclin D3, Mcl-1 and c-Myc mRNA in Jeko and Granta cells (Figure 4A). However, CC214-1 was able to suppress c-Myc and cyclin D3 protein level in a dose dependent manner. Suppression of Mcl-1 was detectable only after treatment with higher concentrations of CC214-1 (Figure 4B).


Translation initiation complex eIF4F is a therapeutic target for dual mTOR kinase inhibitors in non-Hodgkin lymphoma.

Demosthenous C, Han JJ, Stenson MJ, Maurer MJ, Wellik LE, Link B, Hege K, Dogan A, Sotomayor E, Witzig T, Gupta M - Oncotarget (2015)

Effect of mTORC1/mTORC2 inhibitor CC214-1 on expression of eIF4E sensitive mRNAs(A) RT–PCR was performed in the CC214-1 treated Jeko and Granta cells using specific primers for cyclin D3, Mcl-1 and c-Myc. GADPH is shown as a loading control. The experiment was repeated 3 times. (B) Cyclin D3, Mcl-1 and c-Myc protein expression was assessed by western blotting in Jeko cells after treatment with various concentrations of CC214-1. (C) Cyclin D3, Mcl-1 and c-Myc protein expression was assessed in eIF4E shRNA stably transfected HEK293 cells in the presence and absence of CC214-1.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4496233&req=5

Figure 4: Effect of mTORC1/mTORC2 inhibitor CC214-1 on expression of eIF4E sensitive mRNAs(A) RT–PCR was performed in the CC214-1 treated Jeko and Granta cells using specific primers for cyclin D3, Mcl-1 and c-Myc. GADPH is shown as a loading control. The experiment was repeated 3 times. (B) Cyclin D3, Mcl-1 and c-Myc protein expression was assessed by western blotting in Jeko cells after treatment with various concentrations of CC214-1. (C) Cyclin D3, Mcl-1 and c-Myc protein expression was assessed in eIF4E shRNA stably transfected HEK293 cells in the presence and absence of CC214-1.
Mentions: Long, highly structured 5′-UTRs are typical of proto-oncogene mRNAs such as c-Myc, Mcl-1 and Cyclin D3 and considered eIF4E sensitive.[3, 14] To evaluate the effects of treatment with CC214-1 on the transcription of eIF4E known targets, we performed qualitative RT-PCR using specific primers for cyclin D3, Mcl-1 and c-Myc. CC214-1 did not inhibit the transcription of cyclin D3, Mcl-1 and c-Myc mRNA in Jeko and Granta cells (Figure 4A). However, CC214-1 was able to suppress c-Myc and cyclin D3 protein level in a dose dependent manner. Suppression of Mcl-1 was detectable only after treatment with higher concentrations of CC214-1 (Figure 4B).

Bottom Line: Treatment with the active-site dual mTOR inhibitor CC214-1 reduced the level of the eIF4F complex by decreasing the cap bound fraction of eIF4G and increasing the levels of 4E-BP1.Inhibition of eIF4E with shRNA further decreased the CC214-1 induced inhibition of the eIF4F complex, c-Myc, cyclin D3 translation, and colony formation.These studies demonstrate that the eIF4F complex is deregulated in aggressive lymphoma and that dual mTOR therapy has therapeutic potential in these patients.

View Article: PubMed Central - PubMed

Affiliation: Division of Hematology, Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA.

ABSTRACT
Deregulated mRNA translation has been implicated in disease development and in part is controlled by a eukaryotic initiation complex eIF4F (composed of eIF4E, eIF4G and eIF4A). We demonstrate here that the cap bound fraction from lymphoma cells was enriched with eIF4G and eIF4E indicating that lymphoma cells exist in an activated translational state. Moreover, 77% (110/142) of diffuse large B cell lymphoma tumors expressed eIF4E and this was associated with an inferior event free survival. Over-expression of wild-type eIF4E (eIF4E(WT)) but not cap-mutant eIF4E (eIF4E(cap mutant)) increased the activation of the eIF4F complex. Treatment with the active-site dual mTOR inhibitor CC214-1 reduced the level of the eIF4F complex by decreasing the cap bound fraction of eIF4G and increasing the levels of 4E-BP1. CC214-1 inhibited both the cap dependent and global protein translation. CC214-1 inhibited c-Myc, and cyclin D3 translation by decreasing polysomal fractions from lymphoma cells. Inhibition of eIF4E with shRNA further decreased the CC214-1 induced inhibition of the eIF4F complex, c-Myc, cyclin D3 translation, and colony formation. These studies demonstrate that the eIF4F complex is deregulated in aggressive lymphoma and that dual mTOR therapy has therapeutic potential in these patients.

No MeSH data available.


Related in: MedlinePlus