Dataset Information

Combinatorial targeting of nuclear export and translation of RNA inhibits aggressive B-cell lymphoma

ABSTRACT: Aggressive double and triple hit (DH/TH) DLBCL feature activation of Hsp90 stress pathways. Herein, we show that Hsp90 controls post-transcriptional dynamics of key mRNA species including those encoding BCL6, MYC and BCL2. Using a proteomics approach, we found that Hsp90 binds to and maintains activity of eIF4E (eukaryotic translation initiation factor 4E). EIF4E drives nuclear export and translation of BCL6, MYC and BCL2 mRNA. eIF4E RIP-sequencing in DLBCL suggests that nuclear eIF4E controls an extended program that includes BCR signaling, cellular metabolism and epigenetic regulation. Accordingly, eIF4E was required for survival of DLBCL including the most aggressive subtypes DH/TH lymphomas. Indeed, eIF4E inhibition induces tumor regression in cell line and patient-derived tumorgrafts of TH-DLBCL, even in the presence of elevated Hsp90 activity. Targeting Hsp90 is typically limited by counter-regulatory elevation of Hsp70B, which induces resistance to Hsp90 inhibitors. Surprisingly, we identify Hsp70 mRNA as an eIF4E target. In this way, eIF4E inhibition can overcome drug resistance to Hsp90 inhibitors. Accordingly, rational combinatorial inhibition of eIF4E and Hsp90 inhibitors resulted in cooperative anti-lymphoma activity in DH/TH DLBCL in vitro and in vivo.

ORGANISM(S): Homo sapiens

PROVIDER: GSE63265 | GEO | 2016/01/11

SECONDARY ACCESSION(S): PRJNA267117

REPOSITORIES: GEO

ACCESS DATA

Similar Datasets

Project description:Aggressive double and triple hit (DH/TH) DLBCL feature activation of Hsp90 stress pathways. Herein, we show that Hsp90 controls post-transcriptional dynamics of key mRNA species including those encoding BCL6, MYC and BCL2. Using a proteomics approach, we found that Hsp90 binds to and maintains activity of eIF4E (eukaryotic translation initiation factor 4E). EIF4E drives nuclear export and translation of BCL6, MYC and BCL2 mRNA. eIF4E RIP-sequencing in DLBCL suggests that nuclear eIF4E controls an extended program that includes BCR signaling, cellular metabolism and epigenetic regulation. Accordingly, eIF4E was required for survival of DLBCL including the most aggressive subtypes DH/TH lymphomas. Indeed, eIF4E inhibition induces tumor regression in cell line and patient-derived tumorgrafts of TH-DLBCL, even in the presence of elevated Hsp90 activity. Targeting Hsp90 is typically limited by counter-regulatory elevation of Hsp70B, which induces resistance to Hsp90 inhibitors. Surprisingly, we identify Hsp70 mRNA as an eIF4E target. In this way, eIF4E inhibition can overcome drug resistance to Hsp90 inhibitors. Accordingly, rational combinatorial inhibition of eIF4E and Hsp90 inhibitors resulted in cooperative anti-lymphoma activity in DH/TH DLBCL in vitro and in vivo. We found that eIF4E activity regulates the nuclear export of BCL6, MYC, and BCL2 in DH/TH DLBCLs. To determine the extent of nuclear eIF4E activity in DH/TH DLBCLs and how these programs can support the oncogenic activity of BCL6, MYC and/or BCL2 transcripts, we conducted eIF4E-RIP of nuclear RNA followed by RNA-sequencing in OCI-Ly1 cells in triplicates. To understand the changes in gene expression after ribavarin in a clinically relevant sample, we generated a patient-derived xenograft (PDX) in NSG mice from a de-identified specimen isolated from a patient prior to treatment harboring a triple-hit ABC-type DLBCL. PDX cells from passage four (PDX-4) were implanted into NSG mice. When tumors were palpable, mice were randomized to receive vehicle or 80 mg/kg/b.i.d. ribavarin intraperitoneally for 10 days. We isolated RNA from tumors treated with vehicle (n=2) or ribavarin (n=2) and performed mRNA-seq.

Project description:Background. Heat shock protein 90 (Hsp90) is essential for the stability and the function of many client proteins, such as ERB2, C-RAF, CDK4, HIF-1 aplha and AKT. Recent reports demonstrated that inhibition of Hsp90 modulates multiple functions required for survival of human cancer, such as myeloma (Mitsiades et al, Blood:107, 1092, 2006), however, the precise mechanism of anti-cancer effect of Hsp90 inhibition is still uncertain. Aim. The aim of this study is evaluate the effect of Hsp90 inhibition, and to identify molecular pathways responsible for anti-proliferative effect on ATL cells. Method. For Hsp90 inhibition, Geldanamycin derivates, 17AAG (17-allylamino -17-demethoxygeldanamycin) and 17DMAG (17-(dimethylaminoethylamino) 17-demethoxygeldanamycin) were used in this study. Interleukin 2-independent ATL cell lines (MT-2 and MT-4) and an interleukin 2-dependent ATL cell line (TaY) were incubated, with or without Hsp90 inhibitors. Fresh ATL cells obtained from patients were also used after obtaining informed consent. Cell numbers at 48 h after incubation with or without Hsp90 inhibitors were assessed with the Cell Counting Kit-8 assay (Dojindo Molecular Technologies, Gaithersburg, MD, USA). For detection of apoptosis, we used Annexin V-biotin apoptosis detection kit (Calbiochem, La Jolla, CA, USA). Gene expression analysis was done using a DNA microarray (NCBI Gene expression omnibus; GPL 2531) and statistical analysis was done by a GeneSifter (VizXlabs, Seattle, WA, USA). Results. We found cell death induced by Hsp90 inhibitors in all the 3 ATL cell lines as well as patient specimens. Inhibitory concentration (IC50) of 17AAG in 3 ATL cell lines was 300 to 700 nM, and that of 17DMAG was 150 to 200 nM. Fresh ATL cells obtained from patients were more sensitive for either 17AAG or 17DMAG. Gene expression analysis of ATL cells revealed that up-regulation of HSPA1A encoding Hsp70, and genes related to cell cycle arrest (i.e. CDKN1A). Genes regulating cell proliferation or anti-apoptosis (i.e. MYC, BCL2 and Cyclin C), genes related to cytokine or chemokine (i.e. IL9, CCL 17, and CCL27), and notably, genes involved in Wnt/-catenin signaling pathway (i.e.TCF7L2 and TCF4), were remarkably repressed. Inhibition of AKT at the protein level was also evident, suggesting the possibility that AKT may down-regulates -catenin/ TCF7L2 pathways in response to Hsp90 inhibitors in ATL cells. Conclusion. Our results have provided new insights into the complex molecular pharmacology of Hsp90 inhibitors, and suggest that Hsp90 inhibitors might be beneficial as anti-proliferative agent in treating ATL patients. Six samples treated with Hsp90 inhibitors (17-AAG or 17-DMAG) were analyzed in biological duplicate.

Project description:Background. Heat shock protein 90 (Hsp90) is essential for the stability and the function of many client proteins, such as ERB2, C-RAF, CDK4, HIF-1 aplha and AKT. Recent reports demonstrated that inhibition of Hsp90 modulates multiple functions required for survival of human cancer, such as myeloma (Mitsiades et al, Blood:107, 1092, 2006), however, the precise mechanism of anti-cancer effect of Hsp90 inhibition is still uncertain. Aim. The aim of this study is evaluate the effect of Hsp90 inhibition, and to identify molecular pathways responsible for anti-proliferative effect on ATL cells. Method. For Hsp90 inhibition, Geldanamycin derivates, 17AAG (17-allylamino -17-demethoxygeldanamycin) and 17DMAG (17-(dimethylaminoethylamino) 17-demethoxygeldanamycin) were used in this study. Interleukin 2-independent ATL cell lines (MT-2 and MT-4) and an interleukin 2-dependent ATL cell line (TaY) were incubated, with or without Hsp90 inhibitors. Fresh ATL cells obtained from patients were also used after obtaining informed consent. Cell numbers at 48 h after incubation with or without Hsp90 inhibitors were assessed with the Cell Counting Kit-8 assay (Dojindo Molecular Technologies, Gaithersburg, MD, USA). For detection of apoptosis, we used Annexin V-biotin apoptosis detection kit (Calbiochem, La Jolla, CA, USA). Gene expression analysis was done using a DNA microarray (NCBI Gene expression omnibus; GPL 2531) and statistical analysis was done by a GeneSifter (VizXlabs, Seattle, WA, USA). Results. We found cell death induced by Hsp90 inhibitors in all the 3 ATL cell lines as well as patient specimens. Inhibitory concentration (IC50) of 17AAG in 3 ATL cell lines was 300 to 700 nM, and that of 17DMAG was 150 to 200 nM. Fresh ATL cells obtained from patients were more sensitive for either 17AAG or 17DMAG. Gene expression analysis of ATL cells revealed that up-regulation of HSPA1A encoding Hsp70, and genes related to cell cycle arrest (i.e. CDKN1A). Genes regulating cell proliferation or anti-apoptosis (i.e. MYC, BCL2 and Cyclin C), genes related to cytokine or chemokine (i.e. IL9, CCL 17, and CCL27), and notably, genes involved in Wnt/beta-catenin signaling pathway (i.e.TCF7L2 and TCF4), were remarkably repressed. Inhibition of AKT at the protein level was also evident, suggesting the possibility that AKT may down-regulates beta-catenin/ TCF7L2 pathways in response to Hsp90 inhibitors in ATL cells. Conclusion. Our results have provided new insights into the complex molecular pharmacology of Hsp90 inhibitors, and suggest that Hsp90 inhibitors might be beneficial as anti-proliferative agent in treating ATL patients.

Dataset Information

Combinatorial targeting of nuclear export and translation of RNA inhibits aggressive B-cell lymphoma

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure