Overcoming Drug Resistance In Acute Lymphoblastic Leukemia by Inhibition of CBP/γ-Catenin

Abstract Abstract 3264 Survivin, an inhibitor of apoptosis protein (IAP) family, has been associated with poor prognosis in cancer including leukemia. Survivin can be downregulated in colon cancer cells by inhibition of the β-catenin/Creb-binding protein (CBP) interaction using ICG-001, a small molecule specific inhibitor of the β-catenin/CBP interaction. We have shown previously that combined ICG-001 and chemotherapy can downregulate Survivin and sensitize ALL cells to chemotherapy in vitro and in a pilot study in vivo. In this study, we determine the CBP interaction with ICG-001 in primary ALL cells and preclinically evaluate ICG-001 in vitro and in vivo as an adjuvant against primary ALL and. For this purpose, primary ALL cells were co-cultured with OP9 cells and treated for 4 days with ICG-001 (10mM, 20mM) or DMSO as vehicle control. Mean viability (trypan blue exclusion) of cells treated with ICG-001 was significantly lower (ICG-001 10mM: 75.12% ± 3.15%; 20mM: 41.18%± 7.88%) compared to cells treated with DMSO (84.99% ± 0.42%) (% cell viability relative to initial control) (p=0.03). Real time RT-PCR showed ICG-001 dose-dependent downregulation of Survivin in ALL compared to control (ICG10mM vs. control: p=0.0037 and 20mM vs. control: p=0.0031). Immunoblotting demonstrated reduction of Survivin after ICG-001 treatment. Primary ALL cells incubated with a combination of VDL (Vincristine, Dexamethasone and L-Asparaginase) and ICG-001 showed decreased viability (28.7%± 4.9%) versus VDL only (79.3%± 13.6%) (p=0.014) determined by MTT assay. To elucidate if ICG-001 interacts with β-catenin/CBP as shown previously in colon cancer, we analyzed ten primary pre-B ALL cells and found significantly greater γ-catenin and Survivin expression versus normal pre-B-Cells. β-catenin was absent or in some cases expressed only weakly. Expression of v-catenin and b-catenin in ALL xenograft cells were detected by Western blot. One primary ALL was selected and incubated with γ-catenin and β-catenin siRNA for 48hrs, followed by 6hrs incubation with Wnt3a. Wnt3a induced both of γ-catenin and β-catenin expression. Survivin was reduced by γ-catenin siRNA but not β-catenin siRNA treatment. Addition of Wnt3a partially recovered the decrease of Survivin. In addition, Survivin was knocked down in primary ALL using shRNA and non-silencing shRNA control or ICG-001 (2uM) and DMSO control. Western blot analysis showed that survivin shRNA or ICG-001 treatment lead to downregulation of Survivin and γ-catenin. Using a ChIP assay we could demonstrate occupancy of TCF4 and CBP association at the Survivin promoter, which was not altered by ICG-001 in primary ALL. Moreover, ICG-001 treatment of primary ALL cells prevents CBP but not p300 occupancy. For further preclinical in vivo evaluation of ICG-001, one Philadelphia chromosome positive ALLs (Ph+) and two Ph− primary ALL were injected into sublethally irradiated NOD/SCID IL2Rγ−/-mice and treated with ICG-001 (50mg or 100mg/kg/day per subcutaneous miniosmotic pump) with or without chemotherapy including VDL for Ph− ALL (per intraperitoneal injections) or Nilotinib for Ph+ ALL (per os). For analysis we pooled the survival of all three primary leukemias. The saline control group (n=10) (MST= 55.5.days) and the ICG-001 only groups (n=3) (MST=61 days) died rapidly. The group treated with chemotherapy (n=13) had a median survival time (MST) of 85 days. In marked contrast, the group treated with the combined chemotherapy+ICG-001 (n=15) lived significantly longer (MST=100) (p<0.05). Taken together, our data shows that Survivin transcription can be mediated by γ-catenin in primary ALL and that targeting CBP/γ-catenin by using ICG-001 ALL can sensitize ALL cells to chemotherapy in vitro and in vivo. Disclosures: No relevant conflicts of interest to declare.

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Elevated ANXA1 Expression Causes Glucocorticoid Resistance in Acute Lymphoblastic Leukemia Via Activating the Wnt/β-Catenin Signaling Pathway

Blood ◽

10.1182/blood-2019-130322 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 5198-5198

Author(s):

Ping Liu ◽

Dan Ma ◽

Jishi Wang

Keyword(s):

Western Blot ◽

Cell Lines ◽

Conflicts Of Interest ◽

Expression Profiles ◽

Lymphoblastic Leukemia ◽

Luciferase Assay ◽

Protein Levels ◽

Leukemia Relapse

Background: Acute lymphoblastic leukaemia (ALL) is one of the most common clonal malignant diseases in children, and it stems from unchecked proliferation of lymphoid progenitor cells. Glucocorticoids (GCs) such as prednisolone and dexamethasone are used as a chemotherapeutic drug in the treatment of ALL. GC-induced cell mortality is first mediated by the activation of glucocorticoid receptor (GR), followed by its translocation into the nucleus to activate or inhibit gene transcription. However, up to ~20% patients with leukemia relapse and become resistant to GCs. Therefore, a better understanding the molecular basis of chemoresistance in ALL would provide novel therapeutic opportunities for patients. Methods: By analyzing the published mRNA expression profiles (GSE5280; GSE94302) obtained from NCBI (https://www.ncbi.nlm.nih.gov/geo/), we found that higher expression of ANXA1 was significantly associated with decreased overall survival of ALL patients. We also examined the expression of ANXA1 at mRNA and protein levels in a variety of ALL cell lines by using qRT-PCR and western blot analyses. The mRNA and protein expression of ANXA1 in ALL cell lines and patients were determined using Real-time PCR and Western blot respectively. Functional assays, such as CCK-8, FACS, and Tunel assay used to determine the oncogenic role of ANXA1 in ALL progression. Furthermore, western blotting and luciferase assay were used to determine the mechanism of ANXA1 promotes chemoresistance in ALL cells. Results: The expression of ANXA1 was markedly upregulated in ALL cell lines and patients, and high ANXA1 expression was associated with relapsed/refractory ALL patients. ANXA1 overexpression confers glucocorticoids (GCs) resistance on ALL cells; however, down-regulated of ANXA1 sensitized ALL cell lines to GC both in vitro and in vivo. Additionally, ANXA1 upregulated the levels of FPRs by promoting Wnt/β-catenin signalling. Conclusions: Our findings provided evidence that ANXA1 is a potential therapeutic target for patients with ALL. Targeting ANXA1 signaling may be a promising strategy to enhance GC response during ALL chemo-resistance. Disclosures No relevant conflicts of interest to declare.

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PI3Kdelta Inhibitor, CAL-101, De-Adheres Primary Pre-B ALL from VCAM-1 and Induces Apoptosis in Primary Pre-B ALL

Blood ◽

10.1182/blood.v124.21.3715.3715 ◽

2014 ◽

Vol 124 (21) ◽

pp. 3715-3715

Author(s):

Sajad Khazal ◽

Enzi Jiang ◽

Stephanie Shishido ◽

Osanna Kosoyan ◽

Kim Hye-Na ◽

...

Keyword(s):

Western Blot ◽

Lymphoblastic Leukemia ◽

Philadelphia Chromosome ◽

Xenograft Model ◽

Lymphocytic Leukemia ◽

Conditional Knockout ◽

Akt Pathway ◽

Integrin Α4

Abstract BACKGROUND: Relapse remains a major problem in the treatment pre-B acute lymphoblastic leukemia (ALL). ALL cells are physically anchored in the bone marrow (BM) microenvironment through a network of adhesion molecules. Adhesion also creates intracellular signals that regulate proliferation and cell death. We have previously identified integrin α4 (α4) as a critical molecule for such cell-adhesion-mediated drug resistance (CAM-DR) in pre-B ALL. In chronic lymphocytic leukemia (CLL), α4-mediated activation of the PI3K/AKT pathway was reported. In ALL, stromal cell protection of B-lineage ALL cells has also been shown to require active Akt. However, it remains elusive how this target can be therapeutically harnessed. Therefore, we investigated if directly targeting the PI3K/AKT pathway downstream of α4 can overcome CAM-DR in pre-B ALL using a novel, FDA-approved PI3Kδ inhibitor, CAL-101 METHODS: For in vitro studies, murine integrin α4 conditional knockout mouse model (α4fl/fl) oncogenically transformed with BCR-ABL1+ and patient-derived (primary) pre-B ALL cells (Philadelphia chromosome negative) co-cultured with murine calvaria-derived mesenchymal stromal (OP9) cells were used. Annexin V/7-AAD staining was used for viability determination by flow cytometry and Western Blot was used for determination of PI3Kδ and p-Akt expression. For in vivo experiments, we used a NOD/SCID IL2Rγ-/- xenograft model of primary pre-B ALL. RESULTS: Integrin α4fl/fl cells were cultured under lymphoid-skewing conditions and oncogenically transformed using BCR-ABL1 (p210). Subsequent transduction with CreERT2 or EmptyERT2 generated leukemia cells in which α4 ablation could be induced (CreERT2) or not (EmptyERT2) by addition of Tamoxifen while plated on murine VCAM-1. In the absence of a4, mouse pre-B ALL cells contain markedly reduced levels of pAKT (ser473). In a parallel experiment, we observed in primary pre-B ALL cells co-cultured with OP9 cells an increase in p-AKT compared to media-only cultured ALL cells indicating activation of the PI3K/AKT pathway upon adhesion to stroma. Under starvation conditions, primary pre-B ALL cells (LAX7R) were incubated for 4 hours without serum or stroma, and subsequently treated for 48 hours with an integrin α4 blocking antibody or with control IgG4. By Western Blot, we detected decreased levels of activated p-AKT in the cells with α4 blockade, but not with control, indicating that the AKT pathway is affected by modulation of α4.To directly target the PI3K/AKT pathway, we used CAL-101, a small molecule inhibitor highly selective for the δ isoform, which was recently FDA-approved for treatment of CLL and Non-Hodgkin Lymphoma (NHL). Previously, in primary samples from CLL patients and ALL cell lines, CAL-101 blocked PI3Kδ-AKT signaling and promoted apoptosis. However, a preclinical evaluation in primary pre-B ALL patients in vitro and in vivo are missing. For these reasons, we used CAL-101 in the following experiments as a specific PI3Kδ inhibitor in primary pre-B ALL. Expression of PI3Kδ was demonstrated by Western Blot in 8 out of 8 cases of primary pre-B ALL. After incubation of primary pre-B ALL cells with different concentrations of CAL-101 (0.1-10 µM), dose-dependent downregulation of pAkt was observed. ALL cells were plated on immobilized VCAM1 (the counter-receptor for α4) or OP9 cells and treated with vehicle control (DMSO) or CAL-101 (10 µM) for 2 days. CAL-101 de-adhered ALL cells 69.5%±0.7% from VCAM1, and only 13%±0.5% from OP-9 cells, indicating an inhibition of the of the VCAM-1 and α4 interaction. ALL cells treated with CAL-101 (10 µM) for 5 days showed a marked decrease in viability as demonstrated by AnnexinV negative and 7AAD negative staining compared to DMSO-treated controls (66.2%±1.5% vs 87.9%±1.0%, p=0.0003) indicating that mono-treatment with CAL-101-decreases viability of ALL cells. Further studies addressing whether PI3Kδ inhibition is beneficial in the setting of combination chemotherapy for ALL in vitro and in vivo are ongoing. CONCLUSION: Taken together, our data demonstrate that the AKT pathway is affected by modulation of α4. PI3Kδ inhibition with CAL-101 de-adheres pre-B ALL cells from the α4-counter-receptor VCAM1, downregulates pAkt and induces apoptosis in ALL. Data derived from further studies will determine the potential of the FDA-approved PI3Kδinhibitor CAL-101 as a novel therapy for pre-B ALL. Disclosures Wayne: MedImmune: Honoraria, Research Funding, Travel Support Other; NIH: Co-inventor on investigational products with patents, Co-inventor on investigational products with patents Other.

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Novel CD19/CD22 Bicistronic Chimeric Antigen Receptors Outperform Single or Bivalent Cars in Eradicating CD19+CD22+, CD19-, and CD22- Pre-B Leukemia

Blood ◽

10.1182/blood.v130.suppl_1.810.810 ◽

2017 ◽

Vol 130 (Suppl_1) ◽

pp. 810-810 ◽

Cited By ~ 3

Author(s):

Haiying Qin ◽

Sang M Nguyen ◽

Sneha Ramakrishna ◽

Samiksha Tarun ◽

Lila Yang ◽

...

Keyword(s):

T Cell ◽

B Cell ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Single Chain ◽

Dual Targeting ◽

Single Antigen ◽

Therapeutic Function

Abstract Treatment of pre-B cell acute lymphoblastic leukemia (ALL) using chimeric antigen receptor expressing T cells (CART) targeting CD19 have demonstrated impressive clinical results in children and young adults with up to 70-90% complete remission rate in multiple clinical trials. However, about 30% of patients relapse due to loss of the targeted epitope on CD19 or CART failure. Our CD22-targeted CAR trial has generated promising results in relapsed/refractory ALL, including CD19 antigen negative ALL, but relapse associated with decreased CD22 site density has occurred. Thus, developing strategies to prevent relapses due to changes in antigen expression have the potential to increase the likelihood of durable remissions. In addition, dual targeting of both CD19 and CD22 on pre-B ALL may be synergistic compared to targeting a single antigen, a potential approach to improve efficacy in patients with heterogeneous expression of CD19 and CD22 on leukemic blasts. We describe the systematic development and comparison of the structure and therapeutic function of three different types (over 15 different constructs) of novel CARs targeting both CD19 and CD22: (1) Bivalent Tandem CAR, (2) Bivalent Loop CAR, and (3) Bicistronic CAR. These dual CARs were assembled using CD19- and CD22-binding single chain fragment variable (scFv) regions derived from clinically validated single antigen targeted CARs. They are structurally different in design: both tandem and loop CARs have the CD19 and CD22 scFv covalently linked in the same CAR in different orders, whereas, bicistronic CARs have 2 complete CAR constructs connected with a cleavable linker. The surface expression on the transduced T cell of the CD19/CD22 dual CARs was detected with CD22 Fc and anti-idiotype of CD19 and compared to single CD19 or CD22 CARs. Activities of dual CARs to either CD19 or CD22 were evaluated in vitro with cytotoxicity assays or killing assays against K562 cells expressing either CD19 or CD22 or both antigens and also tested against a leukemia CD19+/CD22+ cell line, NALM6, and NALM6 with CRISPER/CAS9 knockout of CD19 or CD22 or both antigens. Therapeutic function of the top candidates of the dual CARs was then validated in vivo against these NALM6 leukemia lines. Some of these dual CARs were also further tested against patient-derived xenografts. Finally, we tested the dual targeting CARs in an artificial relapse model in which mice were co-injected with a mix of CD19 knockout and CD22 knockout NALM6 leukemia lines. From these studies, we established that the order of the scFv, size of the linker, type of leader sequence, and co-stimulatory domain in the CAR constructs all impact the efficacy of the dual targeting CARs. Tandem, Loop, and Bicistronic CARs all demonstrate some levels of in vitro and in vivo activities, but the bicistronic CAR was most effective at clearing leukemia and preventing relapse. In the CD19+/CD22+ NALM6 model, bicistronic CAR treated mice remain disease free while CD19 CAR or CD22 CAR treated mice already died or relapsed on day 27. In the relapse model, as expected, CD19 or CD22 single CAR T cell treatment resulted in progression of the corresponding antigen-negative NALM6. Treatment with dual targeted bicistronic CARs resulted in clearance of both CD19 and CD22 negative ALL with durable remission. In summary, we described novel CD19/CD22 dual targeting CARs with robust pre-clinical activity against pre-B cell ALL, and validated this approach in the prevention of resistance to single-antigen targeted CARs in preclinical models. Disclosures No relevant conflicts of interest to declare.

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Taurine Attenuates Carcinogenicity in Ulcerative Colitis-Colorectal Cancer Mouse Model

Oxidative Medicine and Cellular Longevity ◽

10.1155/2020/7935917 ◽

2020 ◽

Vol 2020 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Guifeng Wang ◽

Ning Ma ◽

Feng He ◽

Shosuke Kawanishi ◽

Hatasu Kobayashi ◽

...

Keyword(s):

Colon Cancer ◽

Drinking Water ◽

Mouse Model ◽

Histopathological Examination ◽

Tumor Formation ◽

Water Model ◽

Control Group ◽

Ki 67

Taurine (2-aminoethane-sulfonic acid) is a type of amino acids and has numerous physiological and therapeutic functions, including anti-inflammation. However, there are few studies on the anticancer action of taurine. Our previous studies have demonstrated that taurine exhibits an apoptosis-inducing effect on human nasopharyngeal carcinoma cells in vitro. In this study, we have investigated whether taurine has an anticancer effect, using azoxymethane (AOM)/sulfate sodium (DSS)- induced mouse model for colon carcinogenesis. All mice, except those in control group, received a single intraperitoneal injection of AOM and DSS in the drinking water for 7 days twice, with 1-week interval. After the first DSS treatment, mice were given distilled water (model group) or taurine in the drinking water (taurine group) ad libitum. No tumor was observed in the control group. Taurine significantly suppressed AOM+DSS-induced tumor formation. Histopathological examination revealed AOM/DSS treatment induced colon cancer in all mice (8/8, 100%), and taurine significantly inhibited the progression of colon cancer (4/9, 44.4%). Taurine significantly attenuated cell proliferation in cancer tissues detected by Ki-67 staining. Taurine significantly increased the levels of an apoptosis marker cleaved caspase-9 and tumor suppressor protein PTEN. This is the first study that demonstrated that taurine significantly reduced carcinogenicity in vivo using AOM/DSS-induced colon cancer mouse model.

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miRNA29a Regulates Oncogenic SKI Expression in Acute Myeloid Leukemia (AML).

Blood ◽

10.1182/blood.v114.22.1968.1968 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1968-1968

Author(s):

Sabine Teichler ◽

Thomas Illmer ◽

Thorsten Stiewe ◽

Josephine Roemhild ◽

Andreas Neubauer

Keyword(s):

Western Blot ◽

Conflicts Of Interest ◽

Fragile Site ◽

Micro Rna ◽

Chromosome 7 ◽

Hl60 Cells ◽

Rna Profiling ◽

Micro Rnas

Abstract Abstract 1968 Poster Board I-991 Introduction: AML patients with deletion of chromosome 7 (−7) or deletion of 7q (−7q) have a poor prognosis. We have found that the nuclear oncogene SKI is overexpressed in AML, especially in AML with −7/−7q. SKI acts in AML as a repressor of retinoic acid induced myeloid differentiation (Ritter et al., (2006) Leukemia). As we found SKI up regulated in AML, we asked how SKI expression may be regulated. The aim of our study was to find a molecular background for increased SKI level. On chromosome 7 is a cluster of micro-RNAs (miRNAs) localized particularly around the fragile site 7q32 (Calin et al., (2003) PNAS). Therefore we investigated whether there exists a link between expression of miRNAs localized on chromosome 7 and up regulation of SKI expression in AML. Methods: We used micro RNA profiling analysis, FACS, Western blot, RQ-PCR and luciferase assays to determine the role of miRNA29a in regulating SKI expression. Results: We found that the expression of miRNA25, miRNA29a, miRNA183 and miRNA335 was downregulated in AML patients with -7/-7q. Transfection studies with these four miRNAs in HL60 cells revealed in FACS that miRNA29a inhibits SKI expression (60,4%) compared to nonsense control (100%) and other miRNAs (miRNA25: 91%, miRNA183: 101%, miRNA335: 93%). Western blot experiments confirmed that miRNA29a reduces SKI level in HL60 cells. In keeping, miRNA29a also represses expression of the SKI target gene Nr-CaM in IFB melanoma cells. Knock down of miRNA29a using miRNA29a inhibitor molecules induces SKI expression in the high miRNA29a and low SKI expressing cell line NW1539. Luciferase assays in NW1539 and HeLa transfected with 3′UTR-constructs and HeLa cells cotransfected with miRNA29a demonstrated that miRNA29a binds to 3′UTR of SKI in vitro. Furthermore, comparison of SKI and miRNA29a expression of AML patient samples indicates that miRNA29a expression is associated with low SKI level in vivo. Conclusion: Our data show that miRNA29a which is located on 7q32 regulates expression of the oncogene SKI in vitro and in vivo. We suggest the deletion of miRNA29a as mechanism for up regulation of SKI in AML with -7/-7q and thus propose that in AML, this effect may contribute to the tumor suppressive function of miRNA29a. Disclosures: No relevant conflicts of interest to declare.

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The Small Molecule Inhibitor of VLA4 TBC3486 Sensitizes Resistant ALL to Chemotherapy

Blood ◽

10.1182/blood.v120.21.1500.1500 ◽

2012 ◽

Vol 120 (21) ◽

pp. 1500-1500 ◽

Cited By ~ 2

Author(s):

Yao-Te Hsieh ◽

Eun Ji Gang ◽

Halvard Bonig ◽

Ronald J Biediger ◽

Peter Vanderslice ◽

...

Keyword(s):

Cell Viability ◽

Small Molecule ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Chemotherapy Resistance ◽

Leukemia Cell ◽

The Novel ◽

Small Molecule Inhibition

Abstract Abstract 1500 Significant progress notwithstanding, drug resistant acute lymphoblastic leukemia (ALL) remains a therapeutic challenge, as well as acute and long-term off-target toxicity of anti-ALL therapies can be dose-limiting or debilitating. Therefore, the development of more targeted therapies is desirable. We recently provided evidence that chemotherapy resistance of ALL cells can be partly overcome by interfering with the function of VLA4, the alpha4beta1 integrin, in vivo. In those studies, we used the anti-functional antibody Natalizumab. We extended our studies to an alternative VLA4 inhibitor, the novel non-peptidic small molecule TBC3486. Previous in vitro assays and molecular modeling studies indicate that TBC3486 behaves as a ligand mimetic, competing with VCAM-1 for the MIDAS site of VLA-4. As such, the compound has been shown to be efficacious in VLA-4 dependent models of inflammatory and autoimmune disease. The potential usefulness of this novel inhibitor in leukemia treatment was tested in our established in vitro and in vivo assays. LAX7R cells, primary pre-B-ALL with a normal karyotype from a patient with an early relapse, were used throughout for the studies reported here. LAX7R cells were treated with 25μM TBC3486 or THI0012 control, the inactive enantiomer of TBC3486, and seeded onto plates coated with human VCAM-1. Adhesion, scored after 2 days, was significantly inhibited by TBC3486 compared to control treated cells (7.9%±4.0 vs 95.4%±8.0; p=0.003). Proliferation rate and cell viability were unaffected by the treatments. In a co-culture system of LAX7R cells with OP9 stroma cells, which we use as an in vitro model of stroma-mediated chemotherapy resistance, we assessed differential effects of VDL (Vincristine, Dexamethasone, L-Asparaginase) on leukemia cell survival in the presence or absence of TBC3486. Stromal adhesion significantly protected LAX7R cells against VDL chemotherapy; this effect was significantly attenuated by TBC3486 compared to the control as determined by Trypan blue exclusion of dead cells (Cell viability of 39.9%±5.1 vs. 57.2±1.8; p=0.02). After these encouraging observations, we next evaluated the benefit of TBC3486 on leukemia progression in a xenotransplant assay. LAX7R cells were lentivirally labelled with luciferase for in vivo tracking and injected into NOD/SCID hosts. Three days after leukemia cell transfer, mice received either TBC3486 or THI0012 (control) (10mg/kg/d) daily for 2 weeks (intraperitoneally), with or without VDL chemotherapy. This experiment is in progress, but already survival of leukemia-bearing mice was significantly prolonged, from a median survival time (MST) for control mice of 33 days post-leukemia injection to a MST of 47 days post-leukemia injection for TBC3486 treated mice (p=0.02). Similarly, bioluminescence imaging revealed a marked delay of leukemia cell dissemination (p<0.0001). Taken together, our data demonstrate that small molecule inhibition of VLA4 using the novel TBC3486 is a suitable approach for targeting of chemotherapy-resistant leukemia. Further studies are warranted to understand and evaluate preclinically adjuvant small molecule inhibition of integrins to overcome relapse of ALL. Disclosures: No relevant conflicts of interest to declare.

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Identification of Non-Cardiotoxic hERG1 Blockers to Overcome Chemoresistance in Acute Lymphoblastic Leukemias

Blood ◽

10.1182/blood.v120.21.1506.1506 ◽

2012 ◽

Vol 120 (21) ◽

pp. 1506-1506

Author(s):

Marika Masselli ◽

Serena Pillozzi ◽

Massimo D'Amico ◽

Luca Gasparoli ◽

Olivia Crociani ◽

...

Keyword(s):

Bone Marrow ◽

Mouse Model ◽

Map Kinases ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Significant Proportion ◽

Leukemic Cells ◽

K Channel

Abstract Abstract 1506 Although cure rates for children with acute lymphoblastic leukemia (ALL), the most common pediatric malignancy, have markedly improved over the last two decades, chemotherapy resistance remains a major obstacle to successful treatment in a significant proportion of patients (Pui CH et al. N Engl J Med., 360:2730–2741, 2009). Increasing evidence indicates that bone marrow mesenchymal cells (MSCs) contribute to generate drug resistance in leukemic cells (Konopleva M et al., Leukemia, 16:1713–1724, 2002). We contributed to this topic, describing a novel mechanism through which MSCs protect leukemic cells from chemotherapy (Pillozzi S. et al., Blood, 117:902–914, 2011.). This protection depends on the formation of a macromolecular membrane complex, on the plasma membrane of leukemic cells, the major players being i) the human ether-a-gò-gò-related gene 1 (hERG1) K+ channel, ii) the β1integrin subunit and iii) the SDF-1α receptor CXCR4. In leukemic blasts, the formation of this protein complex activates both the ERK 1/2 MAP kinases and the PI3K/Akt signalling pathways triggering antiapoptotic effects. hERG1 exerts a pivotal role in the complex, as clearly indicated by the effect of hERG1 inhibitors to abrogate MSCs protection against chemotherapeutic drugs. Indeed, E4031, a class III antiarrhythmic that specifically blocks hERG1, enhances the cytotoxicity of drugs commonly used to treat leukemia, both in vitro and in vivo. The latter was tested in a human ALL mouse model, consisting of NOD/SCID mice injected with REH cells, which are relatively resistant to corticosteroids. Mice were treated for 2 weeks with dexamethasone, E4031, or both. Treatment with dexamethasone and E4031 in combination nearly abolished bone marrow engraftment while producing marked apoptosis, and strongly reducing the proportion of leukemic cells in peripheral blood and leukemia infiltration of extramedullary sites. These effects were significantly superior to those obtained by treatment with either dexamethasone alone or E4031 alone. This model corroborated the idea that hERG1 blockers significantly increase the rate of leukemic cell apoptosis in bone marrow and reduced leukemic infiltration of peripheral organs. From a therapeutic viewpoint, to develop a pharmacological strategy based on hERG1 targeting we must consider to circumvent the side effects exerted by hERG1 blockers. Indeed, hERG1 blockers are known to retard the cardiac repolarization, thus lengthening the electrocardiographic QT interval, an effect that in some cases leads to life threatening ventricular arrhythmias (torsades de points). On the whole, it is mandatory to design and test non-cardiotoxic hERG1 blockers as a new strategy to overcome chemoresistance in ALL. On these bases, we tested compounds with potent anti-hERG1 effects, besides E4031, but devoid of cardiotoxicity (e.g. non-torsadogenic hERG1 blockers). Such compounds comprise erythromycin, sertindole and CD160130 (a newly developed drug by BlackSwanPharma GmbH, Leipzig, Germany). We found that such compounds exert a strong anti-leukemic activity both in vitro and in vivo, in the ALL mouse model described above. This is the first study describing the chemotherapeutic effects of non-torsadogenic hERG1 blockers in mouse models of human ALL. This work was supported by grants from the Associazione Genitori contro le Leucemie e Tumori Infantili Noi per Voi, Associazione Italiana per la Ricerca sul Cancro (AIRC) and Istituto Toscano Tumori. Disclosures: No relevant conflicts of interest to declare.

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Curcumin Potentiates Antitumor Activity of Imatinib Via Inhibition of the AKT/mTOR Signaling Pathway and Down-Regulation of Bcr-Abl Gene in Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia

Blood ◽

10.1182/blood.v120.21.3559.3559 ◽

2012 ◽

Vol 120 (21) ◽

pp. 3559-3559

Author(s):

Yuping Gong ◽

Yong Guo ◽

Ting Niu

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Kinase Inhibitor ◽

Conflicts Of Interest ◽

Early Stage ◽

Lymphoblastic Leukemia ◽

Philadelphia Chromosome ◽

Mtor Signaling ◽

Perennial Herb ◽

Apoptosis Protein ◽

Philadelphia Chromosome Positive

Abstract Abstract 3559 Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) is triggered by constitutively activated BCR-ABL and SRC family tyrosine kinases. They interact each other, then activate downstream growth-signaling pathways including Raf/MEK/ERK,Akt/mTOR and STAT5 pathways. The BCR-ABL tyrosine kinase inhibitor imatinib is the standard treatment for Ph+ leukemia. However, response rate of Ph+ ALL to imatinib is low, relapse is frequent and quick. Studies have documented the potential anti-tumor activities of curcumin, a yellow colored polyphenol from the perennial herb Curcuma longa. However, whether curcumin can be used in the therapy for Ph+ALL remains obscure. Here, we reported that curcumin induced autophagic cell death by activating RAF/MEK/ERK pathway in early stage of the 24-hour exposure course, later induced apoptosis by inhibiting AKT/mTOR, ABL/STAT5 signalings, down-regulating expression of bcr/abl gene and Bcl2 anti-apoptosis protein, and up-regulating the expression of pro-apoptosis protein BAX in Ph+ALL cell line SUP-B15. Furthermore, we found curcumin exerted synergetic anti-leukemia effect with imatinib by inhibiting imatinib-mediated up-regulation of the activation of AKT/mTOR signaling and down-regulating expression of bcr/abl gene. It is worth noting that curcumin provide advantages over dexmethasone as to synergetic anti-leukemia effect with imatinib because dexmethasone improved the imatinib-mediated up-regulation of the activation of AKT/mTOR/P70S6 signaling. In primary samples from Ph+ALL patients, curcumin inhibit growth signaling not only in newly-diagnosised patient but also in imatinib-resistant patient. Moreover, curcumin effectively exhibited anti-leukemia efficacy and synergetic anti-leukemia effect with imatinib in Ph+ALL mouse models. These results demonstrate that curcumin may be a promising agent for the treatment of patients with Ph+ ALL, and curcumin might be particularly effective when used with current induction regimens consisting of imatinib with or without chemotherapy for treating Ph+ ALL. [Grant Support:National Natural Science Foundation of China (No.30770912), Foundation of the Science & Technology Department of Sichuan Province (No.2008SZ0017)]. Disclosures: No relevant conflicts of interest to declare.

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Low-dose arsenic trioxide sensitizes glucocorticoid-resistant acute lymphoblastic leukemia cells to dexamethasone via an Akt-dependent pathway

Blood ◽

10.1182/blood-2006-12-060970 ◽

2007 ◽

Vol 110 (6) ◽

pp. 2084-2091 ◽

Cited By ~ 43

Author(s):

Beat C. Bornhauser ◽

Laura Bonapace ◽

Dan Lindholm ◽

Rodrigo Martinez ◽

Gunnar Cario ◽

...

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Arsenic Trioxide ◽

Low Dose ◽

Lymphoblastic Leukemia ◽

Phosphorylation Site ◽

Inhibitory Effect ◽

Resistant Cell ◽

Apoptosis Protein

Abstract Incorporation of apoptosis-inducing agents into current therapeutic regimens is an attractive strategy to improve treatment for drug-resistant leukemia. We tested the potential of arsenic trioxide (ATO) to restore the response to dexamethasone in glucocorticoid (GC)–resistant acute lymphoblastic leukemia (ALL). Low-dose ATO markedly increased in vitro GC sensitivity of ALL cells from T-cell and precursor B-cell ALL patients with poor in vivo response to prednisone. In GC-resistant cell lines, this effect was mediated, at least in part, by inhibition of Akt and affecting downstream Akt targets such as Bad, a proapoptotic Bcl-2 family member, and the X-linked inhibitor of apoptosis protein (XIAP). Combination of ATO and dexamethasone resulted in increased Bad and rapid down-regulation of XIAP, while levels of the antiapoptotic regulator Mcl-1 remained unchanged. Expression of dominant-active Akt, reduction of Bad expression by RNA interference, or overexpression of XIAP abrogated the sensitizing effect of ATO. The inhibitory effect of XIAP overexpression was reduced when the Akt phosphorylation site was mutated (XIAP-S87A). These data suggest that the combination of ATO and glucocorticoids could be advantageous in GC-resistant ALL and reveal additional targets for the evaluation of new antileukemic agents.

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Heat Shock Protein 70 Inhibitor, Alone or in Combination with Bortezomib, Prevented Plasmacytoma Development in Immunodeficient Mice Transplanted with Myeloma Cell Lines

Blood ◽

10.1182/blood.v128.22.5658.5658 ◽

2016 ◽

Vol 128 (22) ◽

pp. 5658-5658

Author(s):

Mariana Bleker de Oliveira ◽

Angela Isabel Eugenio ◽

Veruska Lia Fook Alves ◽

Daniela Zanatta ◽

Mihoko Yamamoto ◽

...

Keyword(s):

Cell Line ◽

Tumor Cells ◽

Cell Lines ◽

Proteasome Inhibitor ◽

Conflicts Of Interest ◽

Control Group ◽

Immunodeficient Mice ◽

Late Apoptosis

Abstract Introduction: HSP70 has an integrative role in protein degradation due to the interaction with many pathways, such as ubiquitin proteasome (UPS), unfolded protein response (UPR) and autophagy. In multiple myeloma (MM) HSP70 is overexpressed and helps to prevent proteotoxic stress and cell death caused by overload of unfolded/misfolded proteins produced by tumor cells. Aims: To explore the role of HSP70 inhibition, isolated or in association with proteasome inhibitor, as therapeutic strategy for MM through in vitro and in vivo analyses. Methods: RPMI8226-LUC-PURO and U266-LUC-PURO bioluminescent cell lines were treated with HSP70 inhibitor (VER155008- 50 μM or 80μM) and proteasome inhibitor (bortezomib 100nM) for evaluation of apoptosis induction by flow cytometry using annexin V and propidium iodide. NOD.Cg-rkdcscid Il2rgtm1Wjl/SzJ immunodeficient mice were used for plasmacytoma xenograft model and treated with intravenous VER155008 (40mg/kg) and bortezomib (1mg/kg), immediately after transplant of RPMI8226-LUC-PURO and U266-LUC-PURO bioluminescent cell lines (N=3 for each group, including controls, bortezomib, VER155008, and combination of bortezomib and VER155008). Bioluminescence was measured in IVIS Kinetic (Capiler Life Science) once a day for seven days. Results: Bortezomib used as single treatment was able to induce apoptosis in RPMI8226-LUC-PURO cell line: the best result for in vitro studies RPMI8226-LUC-PURO was 65% of late apoptosis after treatment with bortezomib. On the other hand, U266-LUC-PURO cell line presented higher percentage of apoptosis when treated with bortezomib and VER155008 combination: U266-LUC-PURO cell line presented more than 60% of late apoptosis after VER155008 (80μM) combined with bortezomib, showing that inhibition of HSP70 could overcome U266-LUC-PURO resistance to bortezomib alone. Mice treated with VER155008, alone or in combination with bortezomib, showed complete inhibition of tumor growth (absence of bioluminescence) for both cell lines when compared with control group after one week of treatment (p<0.001, Two-way ANOVA). Therefore, in vivo studies using mice treated with VER155008, alone or in combination with bortezomib, prevented tumor development after one week of treatment, independent of the cell line used in the xenotransplant. Conclusion: Our study shows that HSP70 and proteasome inhibitors combination induced apoptosis in tumor cells in vivo for both MM cell lines. Since HSP70 is overexpressed in MM and connects several signaling pathways that maintain cell survival, such as UPS, UPR and autophagy, it can represent a key role to establish a new approach for the treatment of MM. Financial support: FAPESP 2010/17668-6 and CNPq (155272/2013-6). UNIFESP Ethics Committee (0219/12). Disclosures No relevant conflicts of interest to declare.

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