Heme Oxygenase-1 (HO-1)/Heat Shock Protein 32 (Hsp32) as a Novel Survival Factor and Target in AML.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1901-1901 ◽  
Author(s):  
Michael Kneidinger ◽  
Karoline V. Gleixner ◽  
Rudin Kondo ◽  
Puchit Samorapoompichit ◽  
Anja Vales ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Growth Inhibition ◽  
Cell Lines ◽  
Heme Oxygenase ◽  
Leukemic Cells ◽  
Heme Oxygenase 1 ◽  
Inflammatory Reactions ◽  
Survival Factor ◽  
Dependent Inhibition

Abstract Heme oxygenase 1 (HO-1), also known as heat shock protein 32 (Hsp32), has recently been identified as a stress-related survival molecule that acts anti-apoptotic and cytoprotective in inflammatory reactions. Recent data suggest that HO-1/Hsp32 is also expressed in neoplastic cells in various malignancies. In the present study, we provide evidence that HO-1 is constitutively expressed in primary leukemic cells in patients with acute myeloid leukemia (AML, n=17) and in various AML cell lines such as HL60, KG1, KG1a, and U937. Expression of HO-1 mRNA was demonstrable by RT-PCR, and the HO-1 protein by immunocytochemistry and Western blotting. In addition, we were able to demonstrate expression of HO-1 mRNA and of HO-1 protein in the CD34+/CD38− progenitor/stem cell fraction in the leukemic clone in patients with AML. The HO-1 inductor hemin (10 μM) was found to promote expression of HO-1 in AML cells. Incubation with the HO-1-targeting drugs pegylated zink protoporphyrin (PEG-ZnPP) or styrene maleic acid-conjugated ZnPP (SMA-ZnPP), resulted in a dose-dependent inhibition of growth of leukemic cells at pharmacologic concentrations (IC50: 5–20 μM for cell lines and primary AML cells). The SMA-ZnPP-induced growth-inhibition of AML cells were found to be associated with induction of apoptosis as evidenced by light microscopy, electron microscopy, and by a Tunel assay. In consecutive experiments, combination experiments were performed using SMA-ZnPP and AML cell lines. In these experiments, SMA-ZnPP was found to synergize with cytarabine in producing growth inhibition in all AML cell lines tested. In summary, these data show that HO-1/Hsp32 is a novel survival factor and interesting target in AML. The clinical significance of this observation remains to be determined in forthcoming trials.

Targeting of heat shock protein 32 (Hsp32)/heme oxygenase-1 (HO-1) in leukemic cells in chronic myeloid leukemia: a novel approach to overcome resistance against imatinib

Blood ◽  
2008 ◽  
Vol 111 (4) ◽  
pp. 2200-2210 ◽  
Author(s):  
Matthias Mayerhofer ◽  
Karoline V. Gleixner ◽  
Julia Mayerhofer ◽  
Gregor Hoermann ◽  
Eva Jaeger ◽  
...  
Keyword(s):  
Heat Shock ◽  
Chronic Myeloid Leukemia ◽  
Heat Shock Protein ◽  
Heme Oxygenase ◽  
Myeloid Leukemia ◽  
Kinase Inhibitors ◽  
Leukemic Cells ◽  
Heme Oxygenase 1 ◽  
Abl Tyrosine Kinase ◽  
Imatinib Resistant

Resistance toward imatinib and other BCR/ABL tyrosine kinase inhibitors remains an increasing clinical problem in the treatment of advanced stages of chronic myeloid leukemia (CML). We recently have identified the heat shock protein 32 (Hsp32)/heme oxygenase-1 (HO-1) as a BCR/ABL-dependent survival molecule in CML cells. We here show that silencing Hsp32/HO-1 in CML cells by an siRNA approach results in induction of apoptosis. Moreover, targeting Hsp32/HO-1 by either pegylated zinc protoporphyrine (PEG-ZnPP) or styrene maleic acid-micelle–encapsulated ZnPP (SMA-ZnPP) resulted in growth inhibition of BCR/ABL-transformed cells. The effects of PEG-ZnPP and SMA-ZnPP were demonstrable in Ba/F3 cells carrying various imatinib-resistant mutants of BCR/ABL, including the T315I mutant, which exhibits resistance against all clinically available BCR/ABL tyrosine kinase inhibitors. Growth-inhibitory effects of PEG-ZnPP and SMA-ZnPP also were observed in the CML-derived human cell lines K562 and KU812 as well as in primary leukemic cells obtained from patients with freshly diagnosed CML or imatinib-resistant CML. Finally, Hsp32/HO-1–targeting compounds were found to synergize with either imatinib or nilotinib in producing growth inhibition in imatinib-resistant K562 cells and in Ba/F3 cells harboring the T315I mutant of BCR/ABL. In summary, these data show that HO-1 is a promising novel target in imatinib-resistant CML.

Expression Pattern and Regulation of Heme Oxygenase-1/Heat Shock Protein 32 in Human Liver Cells

Shock ◽  
2003 ◽  
Vol 20 (2) ◽  
pp. 116-122 ◽  
Author(s):  
Inge Bauer ◽  
Hauke Rensing ◽  
Annekathrein Florax ◽  
Christoph Ulrich ◽  
Georg Pistorius ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Expression Pattern ◽  
Heme Oxygenase ◽  
Human Liver ◽  
Liver Cells ◽  
Heme Oxygenase 1 ◽  
Human Liver Cells

Combination of the AKT Inhibitor Perifosine with the HSP90 Inhibitor 17-(Dimethylaminoethylamino)-17-Demethoxygeldanamycin (17-DMAG) Has Synergistic Activity in Multiple Myeloma (MM).

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1592-1592
Author(s):  
Alissa Huston ◽  
Lanie Francis ◽  
Yazan Alsayed ◽  
Ujjal Singha ◽  
Ganwei Lu ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Cell Lines ◽  
Hsp90 Inhibitor ◽  
Akt Inhibitor ◽  
Inhibition Of Proliferation ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Induction Of Apoptosis ◽  
Dose Dependent

Abstract The serine-threonine kinase AKT is a mediator of tumor proliferation, and its inhibition leads to induction of apoptosis in MM. Heat shock protein-90 (HSP90) is a chaperone protein involved in the refolding of proteins destabilized by stress, including AKT. HSP90 inhibitors have demonstrated in vitro and in vivo activity in MM, and preliminary activity in a phase I clinical trial in MM. We hypothesized that the combination of agents that target two dysregulated pathways in MM, and that interact at the level of AKT will lead to a synergistic cytotoxic activity in MM. MM cell lines with high level of AKT activity (OPM2) and lower AKT activity (multiple dexamethasone-sensitive MM.1S, dexamethasone-resistant MM.1R, and plasma cell leukemia cell line OPM1) were exposed to serial dilutions of perifosine 2-50uM (KRX-0401, Keryx, NY, NY, provided by the NCI) and 17-DMAG 10-200nM (supplied by NCI) alone and in combination for 48 hrs. Inhibition of proliferation was measured using the MTT proliferation assay. Apoptosis was determined using Annexin V/PI flow cytometry analysis (BD Biosciences, CA). Determination of the additive or synergistic effect of the combination was calculated using the CalcuSyn software (Biosoft, MO) based on the Chou-Talalay method. A two-sided t-test was used to determine differences in response. Perifosine induced a dose dependent inhibition of proliferation in all cell lines tested with 30uM inducing 49% inhibition as compared to control and 50uM inducing 60% inhibition in MM.1S cells. Perifosine 30uM induced more significant apoptosis in cell lines with high AKT activity (OPM2) with 51% apoptosis as compared to 14.7% in MM.1S cells with lower AKT activity (p=0.001). 17-DMAG demonstrated a dose dependent inhibition of proliferation and induction of apoptosis in all cell lines tested with 17-DMAG 100nM inducing 40% inhibition as compared to control and 200nM inducing 56% inhibition in MM.1S. There was no differential response to 17-DMAG in cell lines tested. The combination of 30uM perifosine and 100nM 17-DMAG resulted in a significant inhibition of proliferation with 76% inhibition as compared to each agent alone (p=0.0001, perifosine alone vs. combination). The combination was synergistic with a combination index of 0.1 according to the Chou-Talalay method. Apoptosis analysis at 48 hrs demonstrated 13.9% apoptosis with perifosine 30uM, 3.1% with 17-DMAG 100nM alone, and 47.9% with the combination of the two agents (p=0.004 combination vs. perifosine). The combination of the AKT inhibitor, perifosine and HSP90 inhibitor, 17-DMAG demonstrated a synergistic anti-proliferative and pro-apoptotic effect on MM cell lines as compared to each agent alone. Cell lines with higher AKT activity were more sensitive to the AKT inhibitor, perifosine. Targeting both the PI3kinase pathway and the heat shock protein response represents an attractive approach to future therapeutic options in relapsed/refractory MM where drug resistance is often a major problem. Furthermore, the differential activity noted among higher AKT activity and lower AKT activity cell lines raises the possibility of tailoring therapy based on AKT expression levels in the future.

Identification of heat shock protein 32 (Hsp32) as a novel survival factor and therapeutic target in neoplastic mast cells

Blood ◽  
2007 ◽  
Vol 110 (2) ◽  
pp. 661-669 ◽  
Author(s):  
Rudin Kondo ◽  
Karoline V. Gleixner ◽  
Matthias Mayerhofer ◽  
Anja Vales ◽  
Alexander Gruze ◽  
...  
Keyword(s):  
Mast Cells ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Therapeutic Target ◽  
Systemic Mastocytosis ◽  
Heme Oxygenase 1 ◽  
Zinc Protoporphyrin ◽  
Survival Factor ◽  
Myeloid Neoplasm ◽  
Kit D816v

AbstractSystemic mastocytosis (SM) is a myeloid neoplasm characterized by increased survival and accumulation of neoplastic mast cells (MCs). In most patients, the D816V-mutated variant of KIT is detectable. We report here that heat shock protein 32 (Hsp32), also known as heme oxygenase-1 (HO-1), is a novel KIT-inducible survival factor in neoplastic MCs. As assessed by reverse transcription-polymerase chain reaction (RT-PCR), immunocytochemistry, and Western blotting, the KIT D816V+ MC line HMC-1.2 as well as highly enriched primary neoplastic MCs were found to express Hsp32 mRNA and the Hsp32 protein. Moreover, KIT D816V and stem cell factor (SCF)–activated wild-type KIT were found to induce Hsp32 promoter activity, expression of Hsp32 mRNA, and expression of the Hsp32 protein in Ba/F3 cells. Correspondingly, the KIT D816V-targeting drug PKC412 decreased the expression of Hsp32 as well as proliferation/survival in neoplastic MCs. The inhibitory effects of PKC412 on the survival of HMC-1.2 cells were counteracted by the HO-1 inductor hemin or lentiviral-transduced HO-1. Moreover, 2 Hsp32-targeting drugs, pegylated zinc protoporphyrin (PEG-ZnPP) and styrene maleic acid copolymer micelle-encapsulated ZnPP (SMA-ZnPP), were found to inhibit proliferation and to induce apoptosis in neoplastic MCs. Furthermore, both drugs were found to cooperate with PKC412 in producing growth inhibition. Together, these data show that Hsp32 is an important survival factor and interesting new therapeutic target in neoplastic MCs.

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