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Identification of heat shock protein 32 (Hsp32) as a novel target in acute lymphoblastic leukemia.

Cerny-Reiterer S, Meyer RA, Herrmann H, Peter B, Gleixner KV, Stefanzl G, Hadzijusufovic E, Pickl WF, Sperr WR, Melo JV, Maeda H, Jäger U, Valent P - Oncotarget (2014)

Bottom Line: Hsp32-targeting drugs were found to synergize with imatinib, nilotinib, and bendamustine in producing growth inhibition and apoptosis in Ph+ ALL cells.A siRNA against Hsp32 was found to inhibit growth and survival of ALL cells and to synergize with imatinib in suppressing the growth of ALL cells.In conclusion, Hsp32 is an essential survival factor and potential new target in ALL.

View Article: PubMed Central - PubMed

Affiliation: Ludwig Boltzmann Cluster Oncology, Medical University of Vienna, Austria.

ABSTRACT
Heat shock proteins (Hsp) are increasingly employed as therapeutic targets in oncology. We have shown that Hsp32, also known as heme oxygenase-1 (HO-1), serves as survival factor and potential target in Ph+ chronic myeloid leukemia. We here report that primary cells and cell lines derived from patients with acute lymphoblastic leukemia (ALL) express Hsp32 mRNA and the Hsp32 protein in a constitutive manner. Highly enriched CD34+/CD38- ALL stem cells also expressed Hsp32. Two Hsp32-targeting drugs, pegylated zinc protoporphyrine (PEG-ZnPP) and styrene maleic acid-micelle-encapsulated ZnPP (SMA-ZnPP), induced apoptosis and growth arrest in the BCR/ABL1+ cell lines, in Ph- lymphoblastic cell lines and in primary Ph+ and Ph- ALL cells. The effects of PEG-ZnPP and SMA-ZnPP on growth of leukemic cells were dose-dependent. In Ph+ ALL, major growth-inhibitory effects of the Hsp32-targeting drugs were observed in imatinib-sensitive and imatinib-resistant cells. Hsp32-targeting drugs were found to synergize with imatinib, nilotinib, and bendamustine in producing growth inhibition and apoptosis in Ph+ ALL cells. A siRNA against Hsp32 was found to inhibit growth and survival of ALL cells and to synergize with imatinib in suppressing the growth of ALL cells. In conclusion, Hsp32 is an essential survival factor and potential new target in ALL.

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Hsp32-targeting drugs synergize with bendamustine and with BCR/ABL1-targeting drugs in producing growth inhibition and apoptosis in ALL cellsA: The Ph+ ALL cell line TOM-1 was incubated in control medium or various concentrations of imatinib and SMA-ZnPP or a combination of both drugs for 48h. Thereafter, 3H-thymidine incorporation was measured. Results represent the mean±S.D. of triplicate experiments and are expressed in percent of control. B,C: The Ph+ ALL cell line Z-119 was incubated with control medium or various concentrations of imatinib, nilotinib, PEG-ZnPP, or SMA-ZnPP, alone or with a combination (with fixed drug ratio) of these drugs as indicated for 24 hours. Thereafter, the percentages of apoptotic cells were determined by light microscopy. Results represent the mean±S.D. of three independent experiments. D: The ALL cell lines NALM-1 and TOM-1 were left untransfected (Co) or were transfected with a control siRNA against luciferase (Luc siRNA) or siRNA against Hsp32 (200 nM each) as described in the text. 48 hours after transfection, cells were incubated in control medium or various concentrations of imatinib for 48h. Thereafter, 3H-thymidine incorporation was measured. Results represent the mean±S.D. of triplicate experiments and are expressed as percent of control.
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Figure 4: Hsp32-targeting drugs synergize with bendamustine and with BCR/ABL1-targeting drugs in producing growth inhibition and apoptosis in ALL cellsA: The Ph+ ALL cell line TOM-1 was incubated in control medium or various concentrations of imatinib and SMA-ZnPP or a combination of both drugs for 48h. Thereafter, 3H-thymidine incorporation was measured. Results represent the mean±S.D. of triplicate experiments and are expressed in percent of control. B,C: The Ph+ ALL cell line Z-119 was incubated with control medium or various concentrations of imatinib, nilotinib, PEG-ZnPP, or SMA-ZnPP, alone or with a combination (with fixed drug ratio) of these drugs as indicated for 24 hours. Thereafter, the percentages of apoptotic cells were determined by light microscopy. Results represent the mean±S.D. of three independent experiments. D: The ALL cell lines NALM-1 and TOM-1 were left untransfected (Co) or were transfected with a control siRNA against luciferase (Luc siRNA) or siRNA against Hsp32 (200 nM each) as described in the text. 48 hours after transfection, cells were incubated in control medium or various concentrations of imatinib for 48h. Thereafter, 3H-thymidine incorporation was measured. Results represent the mean±S.D. of triplicate experiments and are expressed as percent of control.

Mentions: Next, we examined cooperative drug effects on growth and survival (apoptosis) of ALL cells. We found that Hsp32-targeting drugs synergize with BCR/ABL1 TKI and with bendamustin in inducing growth inhibition and apoptosis in ALL cells (Figure 4A-C). To further validate Hsp32 as a potential drug-partner of TKI in ALL cells, we applied siRNA against Hsp32 and measured the proliferation of ALL cells as well as the response to imatinib. In these experiments, suboptimal concentrations of imatinib were applied. As shown in Figure 4D, addition of Hsp32-specific siRNA was found to potentiate the effects of imatinib on both ALL cell lines examined, TOM-1 and NALM-1.


Identification of heat shock protein 32 (Hsp32) as a novel target in acute lymphoblastic leukemia.

Cerny-Reiterer S, Meyer RA, Herrmann H, Peter B, Gleixner KV, Stefanzl G, Hadzijusufovic E, Pickl WF, Sperr WR, Melo JV, Maeda H, Jäger U, Valent P - Oncotarget (2014)

Hsp32-targeting drugs synergize with bendamustine and with BCR/ABL1-targeting drugs in producing growth inhibition and apoptosis in ALL cellsA: The Ph+ ALL cell line TOM-1 was incubated in control medium or various concentrations of imatinib and SMA-ZnPP or a combination of both drugs for 48h. Thereafter, 3H-thymidine incorporation was measured. Results represent the mean±S.D. of triplicate experiments and are expressed in percent of control. B,C: The Ph+ ALL cell line Z-119 was incubated with control medium or various concentrations of imatinib, nilotinib, PEG-ZnPP, or SMA-ZnPP, alone or with a combination (with fixed drug ratio) of these drugs as indicated for 24 hours. Thereafter, the percentages of apoptotic cells were determined by light microscopy. Results represent the mean±S.D. of three independent experiments. D: The ALL cell lines NALM-1 and TOM-1 were left untransfected (Co) or were transfected with a control siRNA against luciferase (Luc siRNA) or siRNA against Hsp32 (200 nM each) as described in the text. 48 hours after transfection, cells were incubated in control medium or various concentrations of imatinib for 48h. Thereafter, 3H-thymidine incorporation was measured. Results represent the mean±S.D. of triplicate experiments and are expressed as percent of control.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 4: Hsp32-targeting drugs synergize with bendamustine and with BCR/ABL1-targeting drugs in producing growth inhibition and apoptosis in ALL cellsA: The Ph+ ALL cell line TOM-1 was incubated in control medium or various concentrations of imatinib and SMA-ZnPP or a combination of both drugs for 48h. Thereafter, 3H-thymidine incorporation was measured. Results represent the mean±S.D. of triplicate experiments and are expressed in percent of control. B,C: The Ph+ ALL cell line Z-119 was incubated with control medium or various concentrations of imatinib, nilotinib, PEG-ZnPP, or SMA-ZnPP, alone or with a combination (with fixed drug ratio) of these drugs as indicated for 24 hours. Thereafter, the percentages of apoptotic cells were determined by light microscopy. Results represent the mean±S.D. of three independent experiments. D: The ALL cell lines NALM-1 and TOM-1 were left untransfected (Co) or were transfected with a control siRNA against luciferase (Luc siRNA) or siRNA against Hsp32 (200 nM each) as described in the text. 48 hours after transfection, cells were incubated in control medium or various concentrations of imatinib for 48h. Thereafter, 3H-thymidine incorporation was measured. Results represent the mean±S.D. of triplicate experiments and are expressed as percent of control.
Mentions: Next, we examined cooperative drug effects on growth and survival (apoptosis) of ALL cells. We found that Hsp32-targeting drugs synergize with BCR/ABL1 TKI and with bendamustin in inducing growth inhibition and apoptosis in ALL cells (Figure 4A-C). To further validate Hsp32 as a potential drug-partner of TKI in ALL cells, we applied siRNA against Hsp32 and measured the proliferation of ALL cells as well as the response to imatinib. In these experiments, suboptimal concentrations of imatinib were applied. As shown in Figure 4D, addition of Hsp32-specific siRNA was found to potentiate the effects of imatinib on both ALL cell lines examined, TOM-1 and NALM-1.

Bottom Line: Hsp32-targeting drugs were found to synergize with imatinib, nilotinib, and bendamustine in producing growth inhibition and apoptosis in Ph+ ALL cells.A siRNA against Hsp32 was found to inhibit growth and survival of ALL cells and to synergize with imatinib in suppressing the growth of ALL cells.In conclusion, Hsp32 is an essential survival factor and potential new target in ALL.

View Article: PubMed Central - PubMed

Affiliation: Ludwig Boltzmann Cluster Oncology, Medical University of Vienna, Austria.

ABSTRACT
Heat shock proteins (Hsp) are increasingly employed as therapeutic targets in oncology. We have shown that Hsp32, also known as heme oxygenase-1 (HO-1), serves as survival factor and potential target in Ph+ chronic myeloid leukemia. We here report that primary cells and cell lines derived from patients with acute lymphoblastic leukemia (ALL) express Hsp32 mRNA and the Hsp32 protein in a constitutive manner. Highly enriched CD34+/CD38- ALL stem cells also expressed Hsp32. Two Hsp32-targeting drugs, pegylated zinc protoporphyrine (PEG-ZnPP) and styrene maleic acid-micelle-encapsulated ZnPP (SMA-ZnPP), induced apoptosis and growth arrest in the BCR/ABL1+ cell lines, in Ph- lymphoblastic cell lines and in primary Ph+ and Ph- ALL cells. The effects of PEG-ZnPP and SMA-ZnPP on growth of leukemic cells were dose-dependent. In Ph+ ALL, major growth-inhibitory effects of the Hsp32-targeting drugs were observed in imatinib-sensitive and imatinib-resistant cells. Hsp32-targeting drugs were found to synergize with imatinib, nilotinib, and bendamustine in producing growth inhibition and apoptosis in Ph+ ALL cells. A siRNA against Hsp32 was found to inhibit growth and survival of ALL cells and to synergize with imatinib in suppressing the growth of ALL cells. In conclusion, Hsp32 is an essential survival factor and potential new target in ALL.

Show MeSH
Related in: MedlinePlus