scholarly journals Interleukin 1 Beta As a Promising Therapeutic Target in ABL Tyrosine Kinase Inhibitor Resistant Chronic Myeloid Leukemia Cells

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4249-4249
Author(s):  
Seiichi Okabe ◽  
Tetsuzo Tauchi ◽  
Yuko Tanaka ◽  
Kazuma Ohyashiki

Abstract Introduction: Although ABL tyrosine kinase inhibitor (TKI), imatinib, nilotinib and dasatinib have demonstrated the potency against chronic myeloid leukemia (CML) and Philadelphia chromosome (Ph) positive acute lymphoblastic leukemia (Ph+ALL) patients, resistance to ABL TKI can develop in the many patients. It has already reported that ABL kinase domain mutations have been implicated in the pathogenesis of ABL TKI resistance, however, it is fully not known the molecular mechanism of drug resistance ABL TKIs. Therefore, new approach against ABL TKI resistant cells may improve the outcome of Ph-positive leukemia patients. Interleukin-1 (IL-1) is a proinflammatory cytokine and central mediator of innate immunity. IL-1β also controls essential cell responses. Because enhanced IL-1β signaling is reported in patients of hematological malignancies, IL-1β may be the promising therapeutic value in ABL TKI resistant CML patients. Materials and methods: In this study, we established ABL TKI-resistant in vitro cell line models (K562 imatinib-R, K562 nilotinib-R, K562 dasatinib-R, K562 ponatinib-R). We also investigated whether IL-1β was involved in ABL TKI resistant Ph-positive leukemia cells and cytokines were induced by IL-1β in human umbilical vein endothelial cells (HUVEC). Results: We analyzed the relationship of IL-1β signaling pathways and ABL TKI sensitivity by microarray gene expression data from the online Gene Expression Omnibus (GEO). IL-1β is related to imatinib sensitivity and resistant in CML patients from the public microarray datasets of GSE14671. We next examined ABL TKI resistant cell lines (K562 imatinib-R, K562 nilotinib-R, K562 dasatinib-R, K562 ponatinib-R) in this study. BCR-ABL point mutation was not found in ABL TKI resistant cells. BCR-ABL expression levels were not increased in ABL TKI resistant K562 cells. These cells were highly resistant to ABL TKIs compare to K562 cells (K562 imatinib-R: imatinib 2μM, nilotinib-R: nilotinib 2μM, dasatinib-R: dasatinib 100nM, ponatinib-R: ponatinib 50nM). We investigated gene expression profiles in cultured ABL TKI resistant K562 cells by DNA microarray. We found gene expression of IL-1β and IL-1β mediated signaling pathway was increased ABL TKI resistant K562 cells. IL-1β gene amplification was confirmed by RT-PCR analysis. Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-kB) acts as a central mediator of inflammatory responses. Because bortezomib is a proteasome inhibitor whose anti-cancer action is partly mediated through inhibition of NF-κB, we examined the bortezomib in ABL TKI resistant cells. Combined treatment of ABL TKI resistant cells with ponatinib or imatinib and bortezomib caused more cytotoxicity than each drug alone. Caspase 3/7 activity and cellular cytotoxicity was also increased. ABL TKIs are also associated with vascular adverse events (VAEs) in CML, we next investigated the in vitro effects of ABL TKIs on cultured HUVEC. We found gene expression of IL-1β was increased after ABL TKI especially dasatinib and ponatinib treatment. IL-1β was increased in the cell culture supernatant after ABL TKIs treatment. In the immunoblot analysis, p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) phosphorylation was increased by IL-1β in the time dependent manner. We also found that gene expression of IL-6, IL-8, intercellular adhesion molecule 1 (ICAM1) and monocyte chemotactic protein-1 (MCP-1) was enhanced by IL-1β stimulation. Conclusion: The IL-1β signaling pathway is involved in ABL TKI sensitivity and drug resistant in CML cells and plays a key role in cytokine production of the HUVEC. We also provide the promising clinical relevance as a candidate drug for treatment of ABL TKI resistant leukemia patients. Disclosures Ohyashiki: Asahikase: Research Funding; Taiho Pharmaceutical KK: Honoraria, Research Funding; Dainippon Sumitomo KK,: Honoraria, Research Funding; MSD,: Honoraria, Research Funding; Bristol Meyer Squibb KK,: Honoraria, Research Funding; Ono Pharmaceutical KK,: Honoraria, Research Funding; Celegene KK,: Honoraria, Research Funding; Pfizer KK,: Honoraria, Research Funding; Kyowakko Kirin KK,: Research Funding; Nihon-Seiyaku,: Research Funding; Eizai,: Research Funding; Chugai KK,: Honoraria, Research Funding; Takeda Pharmaceutical KK,: Honoraria, Research Funding; Asteras KK,: Research Funding; Jansen Pharma KK,: Research Funding; Nippon-shinyaku,: Honoraria, Research Funding; Novartis KK,: Honoraria, Research Funding.

Blood ◽  
2000 ◽  
Vol 96 (9) ◽  
pp. 3195-3199 ◽  
Author(s):  
J. Tyler Thiesing ◽  
Sayuri Ohno-Jones ◽  
Kathryn S. Kolibaba ◽  
Brian J. Druker

Abstract Chronic myelogenous leukemia (CML), a malignancy of a hematopoietic stem cell, is caused by the Bcr-Abl tyrosine kinase. STI571(formerly CGP 57148B), an Abl tyrosine kinase inhibitor, has specific in vitro antileukemic activity against Bcr-Abl–positive cells and is currently in Phase II clinical trials. As it is likely that resistance to a single agent would be observed, combinations of STI571 with other antileukemic agents have been evaluated for activity against Bcr-Abl–positive cell lines and in colony-forming assays in vitro. The specific antileukemic agents tested included several agents currently used for the treatment of CML: interferon-alpha (IFN), hydroxyurea (HU), daunorubicin (DNR), and cytosine arabinoside (Ara-C). In proliferation assays that use Bcr-Abl–expressing cells lines, the combination of STI571 with IFN, DNR, and Ara-C showed additive or synergistic effects, whereas the combination of STI571 and HU demonstrated antagonistic effects. However, in colony-forming assays that use CML patient samples, all combinations showed increased antiproliferative effects as compared with STI571 alone. These data indicate that combinations of STI571 with IFN, DNR, or Ara-C may be more useful than STI571 alone in the treatment of CML and suggest consideration of clinical trials of these combinations.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3693-3693
Author(s):  
Seiichi Okabe ◽  
Tetsuzo Tauchi ◽  
Yuko Tanaka ◽  
Juri Sakuta ◽  
Kazuma Ohyashiki

Abstract Introduction: Chronic myeloid leukemia (CML) is characterized by the t(9:22) translocation known as the Philadelphia chromosome (Ph). ABL tyrosine kinase inhibitor (TKI), imatinib and second-generation ABL TKIs, nilotinib and dasatinib have demonstrated the potency against CML patients. However, resistance to ABL TKI can develop in CML patients due to BCR-ABL point mutations. Moreover, ABL TKIs do not eliminate the leukemia stem cells (LSCs). Therefore, new approach against BCR-ABL mutant cells and LSCs may improve the outcome of Ph-positive leukemia patients. In eukaryotic cells, histone acetylation/deacetylation is important in transcriptional regulation. Chromatin acetylation is controlled by the opposing effects of two families of enzymes: histone acetyltransferases (HAT) and histone deacetylases (HDACs). Deregulation of HDAC activity may be a cause of malignant disease in humans. Phosphoinositide 3-kinase (PI3K) pathway also regulates cell metabolism, proliferation and survival. Furthermore, aberrant activation of PI3K signaling pathway has been shown to be important in initiation maintenance of human cancers. CUDC-907 is an oral inhibitor of class I PI3K as well as class I and II HDAC enzymes. CUDC-907 is currently being investigated in a pivotal phase 1 clinical trial against hematological malignancies such as malignant lymphoma. We suggested that CUDC-907 mediated inhibition PI3K and HDAC activity and in combination with ABL TKIs may abrogate the proliferation and survival of Ph-positive leukemia cells including T315I mutation and ABL TKI resistant. Materials and methods: In this study, we investigated the combination therapy with a CUDC-907 and an ABL TKIs (imatinib, nilotinib and ponatinib) by using the BCR-ABL positive cell line, K562, murine Ba/F3 cell line which was transfected with T315I mutant, nilotinib resistant K562 and ponatinib resistant Ba/F3 cells and primary samples. Results: The treatment of imatinib, nilotinib and ponatinib exhibits cell growth inhibition partially against K562 cells in the presence of feeder cell (HS-5). We found that mRNA of PI3K subunit is significantly increased after a co-culture with HS-5 in K562 and primary CD34 positive CML samples. 72 h treatment of CUDC-907 exhibits cell growth inhibition and induced apoptosis against K562 cells in a dose dependent manner. We examined the intracellular signaling after treatment of CUDC-907. Phosphorylation of JNK, histone acetylation and activity of caspase 3, poly (ADP-ribose) polymerase (PARP) was increased. Anti-apoptotic protein, Mcl-1 was decreased in a dose dependent. We next investigated the efficacy between imatinib and CUDC-907 by using these cell line. Combined treatment of K562 cells with imatinib and CUDC-907 caused significantly more cytotoxicity than each drug alone. Caspase activity was increased and Akt activity was reduced. Phosphorylation of BCR-ABL, Crk-L was reduced and cleaved PARP was increased after imatinib and CUDC-907 treatment. We investigated the CUDC-907 activity against T315I positive cells. CUDC-907 potently induced cell growth inhibition of Ba/F3 T315I cells in a dose dependent manner. Combined treatment of Ba/F3 T315I cells with ponatinib and CUDC-907 caused significantly more cytotoxicity than each drug alone. Caspase activity was increased and Akt activity was reduced after ponatinib and CUDC-907 treatment. To assess the activity of ponatinib and CUDC-907, we performed to test on tumor formation in mice. We injected nude mice subcutaneously with Ba/F3 T315I mutant cells. A dose of 20 mg/kg/day p.o of ponatinib and 30 mg/kg/day p.o of CUDC-907 inhibited tumor growth and reduced tumor volume compared with control mice. The treatments were well tolerated with no animal health concerns observed. We also found that the treatment of CUDC-907 exhibits cell growth inhibition against Ba/F3 ponatinib resistant cells, K562 nilotinib resistant cells, T315I mutant primary samples and CD34 positive CML samples. Conclusion: These results indicated that administration of the dual PI3K and HDAC inhibitor, CUDC-907 may be a powerful strategy against ABL TKI resistant cells including T315I mutation and enhance cytotoxic effects of ABL TKI against those Ph-positive leukemia cells. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4043-4043
Author(s):  
Pamela S. Becker ◽  
Sylvia Chien ◽  
Timothy J Martins ◽  
Andrew Herstein ◽  
Cody Hammer ◽  
...  

Abstract Introduction: Acute myeloid leukemia (AML) is a heterogeneous disorder such that each patient exhibits a unique pattern of mutations. Nevertheless, standard treatment approaches are largely used for all patients with the exception of those with the PML-RARA translocation or FLT3 mutations. We are conducting a feasibility study, "Individualized Treatment for Relapsed/Refractory Acute Leukemia Based on Chemosensitivity and Genomics/Gene Expression Data" (NCT02551718). This abstract summarizes the results in the AML patients. . Methods: The primary objective of this trial is to test the feasibility of rapidly assessing patient cells using a high throughput assay for in vitro drug sensitivity with individual drugs and drug combinations and mutation profiling by next generation sequencing (NGS) of 194 genes (MyAML) to enable prompt initiation of optimal therapy. The secondary objective is to evaluate the response to the chosen therapy. The eligibility criteria include diagnosis of acute leukemia, age ≥ 3, relapsed after or refractory to 2 prior lines of therapy, ECOG ≤ 3, and adequate organ function. The high throughput screen (HTS) is performed at a core facility under CLIA. The custom Oncopanel1 contains 160 drugs and drug combinations, including FDA approved and investigational agents, targeted agents including kinase, mTOR, proteasome, HDAC and other inhibitors, and chemotherapy drugs including alkylators, purine analogs, topoisomerase inhibitors and others. Patient blood or marrow samples enriched for leukemia cells are analyzed for survival after a 72-hour exposure to 8 customized drug concentrations spanning 4 logs in duplicate in 384 well plates adherent to matrix protein. DNA and RNA are isolated from the same enriched cell fractions for NGS (MyAML) and RNAseq. MyAML analyzes genes at high depth, including breakpoint hotspot loci with optimized detection of large insertion and deletions and other structural variants found in AML. Results: Fourteen patients signed consent, and 11 AML patients were enrolled in the study to date. Seven patients had unfavorable and 4 intermediate cytogenetic risk. Four were primary refractory, 5 had antecedent hematologic disorder. The average number of prior regimens was 4 (range 2 to 6). Six patients had relapsed within ≤3 months after allogeneic transplant, prior to enrollment on this study. HTS results were obtained within an average of 5.5 days; mutation testing was obtained within an average of 13 days (range 9-17), return time after receipt at MyAML was on average 8 (range 7-12) days. Drug regimens were chosen within 1-2 weeks from testing. For 2 patients, treatment start was delayed by about one month to allow recovery from toxicity from prior therapy. For the other patients, treatment was initiated on average 7.8, median 8 (range 4-11) days from start of testing. Of 7 patients treated so far, the median overall survival was 171 days, range 70 to >289 days. Regimens chosen based on HTS results, mutation analysis, and ability to obtain FDA approved drugs off label included: bortezomib (B)/daunorubicin/cytarabine, romidepsin, B/azacitidine (Aza), B/idarubicin (2 patients),cladribine, omacetaxine (HHT) then HHT/cytarabine, B/Aza/sorafenib, gemcitabine, bortezomib, sorafenib. Mutation analysis revealed previously unknown potential targets in those patients, including ABL kinase, FLT3 ITD in 2 patients, and FLT3 TKD mutations that led to choice of treatment with imatinib, sorafenib, and investigational Flt3 inhibitor for 4 patients, respectively. Other potentially targetable mutations identified included IDH1/2, NRAS, KRAS, KIT, TP53, WT1, and others (Table). None of these very heavily pre-treated patients obtained a complete remission, but 3 remain alive > 1 yr post early relapse after allogeneic transplant. One patient's marrow exhibited decline in blasts from 82% to 24%, and all patients exhibited a decline in circulating blasts with the chosen treatments. Conclusion: This trial has proven that application of rapid molecular and functional screening to choice of treatment for patients with advanced acute myeloid leukemia is feasible. Direct comparison of this precision medicine approach to results obtained with standard trials is planned. These data and the responses and correlation with gene expression data will contribute to a future algorithm to optimize precision medicine approaches to leukemia therapy. Table Table. Disclosures Becker: JW Pharmaceutical: Research Funding; Millennium: Research Funding; Glycomimetics: Research Funding; Pfizer: Other: Scientific Steering Committee for a post marketing study; Amgen: Research Funding; CVS Caremark: Other: Accordant Health Services Medical Advisory Board; Abbvie: Research Funding; Invivoscribe: Honoraria. Patay:Invivoscribe, Inc: Consultancy. Carson:Invivoscribe, Inc: Employment. Radich:Novartis: Consultancy, Other: laboratory contract; Bristol-MyersSquibb: Consultancy; TwinStrand: Consultancy; ARIAD: Consultancy; Pfizer: Consultancy.


Blood ◽  
2002 ◽  
Vol 100 (3) ◽  
pp. 1068-1071 ◽  
Author(s):  
Russell R. Hoover ◽  
Francois-Xavier Mahon ◽  
Junia V. Melo ◽  
George Q. Daley

Abstract The development of chronic myeloid leukemia (CML) is dependent on the deregulated tyrosine kinase of the oncoprotein BCR-ABL. STI571 (imatinib mesylate), an abl tyrosine kinase inhibitor, has proven remarkably effective for the treatment of CML. However, resistance to STI571 because of enhanced expression or mutation of theBCR-ABL gene has been detected in patients. In the current study we show that the farnesyl transferase inhibitor (FTI) SCH66336 (lonafarnib) inhibits the proliferation of STI571-resistant BCR-ABL–positive cell lines and hematopoietic colony formation from peripheral blood samples of STI571-resistant patients with CML. Moreover, SCH66336 enhances STI571-induced apoptosis in STI571-sensitive cells and, in patients with STI571 resistance from gene amplification, cooperates with STI571 to induce apoptosis. Our data provide a rationale for combination clinical trials of STI571 and SCH66336 in CML patients and suggest that combination therapy may be effective in patients with STI571 resistance.


2021 ◽  
Vol 14 (3) ◽  
pp. 1441-1446
Author(s):  
Zakaria Maat ◽  
Kamran Mushtaq ◽  
Mohamed A. Yassin

Dasatinib is a BCR-ABL tyrosine kinase inhibitor which was approved in 2006 for the treatment of adults diagnosed with Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML) in chronic phase (CP) and accelerated (myeloid or lymphoid blast) phase and CML with resistance or intolerance to prior therapy including imatinib and in adults with Ph+ acute lymphoblastic leukemia. Common adverse reactions (>15%) in patients diagnosed with CP-CML include myelosuppression, fluid retention, and diarrhea. We report a 34-year-old Filipino female patient who received dasatinib as upfront therapy for the treatment of CP-CML who experienced chronic diarrhea for 2 months, which progressed to colitis.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5369-5369
Author(s):  
Seiichi Okabe ◽  
Yuko Tanaka ◽  
Mitsuru Moriyama ◽  
Akihiko Gotoh

Introduction: ABL tyrosine kinase inhibitors (TKIs) improved outcomes for patients with chronic myeloid leukemia (CML) and Philadelphia chromosome (Ph)-positive leukemia, however, some patients are still resistance to ABL TKIs. One of the most common mechanisms involves point mutations in the kinase domain of BCR-ABL1, however, mechanisms of intrinsic resistance without point mutation of ABL kinase domain are not fully understood. Moreover, ABL TKIs cannot cure the Ph-positive leukemia patients because of leukemia stem cells in the bone marrow niche. Therefore, new approach against leukemia stem cells may improve the outcome of Ph-positive leukemia patients. Hypoxia is an important component of the bone marrow microenvironment. Because oxygen tension plays a key role in driving normal hematopoiesis, leukemia stem cells may be maintained in hypoxic areas of the bone marrow. Materials and methods: In this study, we established ABL TKI-resistant in vitro cell line models (K562 imatinib-R, K562 nilotinib-R, K562 dasatinib-R, K562 ponatinib-R and Ba/F3 T315I). We investigated gene expression profiles in cultured ABL TKI resistant cells and parental cell line, K562 in normoxia and hypoxia condition by DNA microarray. Results: We first investigated gene expression profiles in cultured K562 cells in hypoxia condition. We found gene expression of insulin-like growth factor 1 (IGF1) was increased K562 cells in hypoxia condition by DNA microarray. We next examined ABL TKI resistant cell lines (K562 imatinib-R, K562 nilotinib-R, K562 dasatinib-R, K562 ponatinib-R) in this study. We could not detect the BCR-ABL point mutation in ABL TKI resistant cells. We found gene expression of insulin-like growth factor 1 (IGF1) receptor (IGF1R) was increased ABL TKI resistant K562 cells. IGF1R gene amplification was confirmed by RT-PCR analysis. IGF is tightly regulated by six related IGF-binding proteins (IGFBPs). One of IGFBP, IGFBP5 is related to imatinib sensitivity and resistant in chronic myeloid leukemia (CML) patients (GSE12211). In hypoxia condition, several IGFBPs were also increased in ABL TKI resistant cells. IGF cause intracellular signaling that ultimately results in cellular growth and proliferation. Thus, we initially examined whether addition of IGF1R inhibition could enhance ABL TKIs sensitivity. One of IGF1R inhibitor, linsitinib was inhibited ABL TKI resistant cells and parental cell line, K562 in hypoxia condition. ABL TKI resistant cell lines were more sensitive against linsitinib. Combined treatment of ABL TKI resistant cells and K562 cells with ABL TKIs and linsitinib caused more cytotoxicity than each drug alone in hypoxia condition. Caspase 3/7 activity and cellular cytotoxicity was also increased after ABL TKIs and linsitnib treatment. In the colony formation method, the number of cell colonies were also reduced in hypoxia condition. Intracellular ATP levels have been implicated in vitro as a determinant of cell death by apoptosis. The concentrations of intracellular ATP were reduced after ABL TKIs and linsitinib. We next blocked IGF1R function by small interfering RNA (siRNA). SiRNA transfected cells were reduced cellular proliferation. We also found drug sensitivity of the cells to the imatinib was increased compared to mock-transfected cells. Apoptotic cells and caspase 3/7 activity were increased after imatinib treatment in siRNA transfected cells. Conclusion: The IGF1 pathway is involved in Ph-positive leukemia cells in hypoxia condition and ABL TKI resistant in CML cells. We also provide the promising clinical relevance as a candidate drug for treatment of residual leukemia cells in bone marrow niche which is in hypoxia condition. Disclosures No relevant conflicts of interest to declare.


2021 ◽  
Vol 9 (41) ◽  
pp. 54-57
Author(s):  
Dhara Dave ◽  
John Kimbugwe ◽  
Randa Hazam ◽  
Saria Tasnim ◽  
Manish Patel

The BCR-ABL tyrosine kinase inhibitor dasatinib is a potent treatment for chronic myeloid leukemia (CML). However, it is associated with pulmonary toxicities. Commonly reported dasatinib related pulmonary toxicities include pleural effusion, lung parenchymal abnormalities, and pulmonary hypertension. Diffuse alveolar hemorrhage (DAH) during treatment with dasatinib is very rare. To the best of our knowledge there are only two cases reported. Here we report a 57-year-old Caucasian woman who developed acute hypoxic respiratory failure while on dasatinib for treatment of CML. She was diagnosed with DAH suspected to be secondary to dasatinib, after other common etiologies were ruled out. There was full recovery after stopping dasatinib and treatment with corticosteroids. Keywords: Dasatinib, pulmonary toxicity, diffuse alveolar hemorrhage, chronic myeloid leukemia


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4242-4242
Author(s):  
Jishi Wang

Abstract Objective : HO-1 is a microsomal enzyme catalyzing the first, rate-limiting step in degradation of heme, HO-1 is a inducible isoform of HO, it can be strongly induced in response to cellular stress and diverse oxidative stimuli, including its substrate heme, Many studies have convincingly shown that HO-1 is a cytoprotective and antiapoptotic enzyme. the objective of this study was to investigate the influence on the K562 cell growth and apoptosis after hemin-induced HO-1 expression, and to investigate the influence on K562 cells and imatinib-resistant CML cells after ZnPPIX-induced HO-1 inhibition. Methods: different concentrations hemin (0umol/l A20umol/l 30umol/l)was used respectively to induce HO-1 expression of cultured chronic myeloid leukemia cell line K562, then detected HO-1 mRNA expression under different time by RT-PCR, and MTT was used to detected the viability of K562 cells. In addition, we used STI571(2 μmol/L) deal with the hemin-induced cells, then confirm HO-1 protective effect against STI571 use MTT. Then ZnPPIX was used to inhibition HO-1 expression of K562 and imatinib-resistant cells, similarly, RT-PCR and MTT was used for analyzed. Results: The HO-1 mRNA was not tested when absence of hemin, 8h after treated with hemin of 20 μmol/L, we can test the HO-1 mRNA expression, and at 16h the expression is reach to the peak, 16h after treated hemin under different concentrations (10umol/l, 20umol/l, 30umol/l), we found the expression is in a dose-dependent manner. In the group of 10 umol/l and 20 umol/l, the survival of cells is significantly increased in comparison to the control and also have significantly difference in the two groups(p<0.05), in the group of 20 μmol/L, 16h to 48h after hemin-induced, the survival of cells presents a time-dependent manner. In the group of 10μmol/L and 20 μmol/L, exposure of K562 cells to STI571 resulted in a substantial decrease of cell viability in comparison to the STI571 single treatment group(p<0.05). ZnPPIX-induced HO-1 inhibition leads to induction of apoptosis in K562 cells, having significant difference with the control group(p<0.05). ZnPPIX-induced HO-1 inhibition can suppress the survival of imatinib-resistant cells(p<0.05). Conclusion: our studies have shown that hemin-induced HO-1 gene expression may promote the proliferation of K562 cells, and can against the cell apoptosis. And we found hemin-induced HO-1 gene expression can protect K562 cells against STI571-induced apoptosis, ZnPPIX-induced HO-1 inhibition leads to decreased viability of imatinb-resistant CML cells. these all indicates HO-1 may represent a novel targeting in CML.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2745-2745 ◽  
Author(s):  
Deborah L. White ◽  
Liu Lu ◽  
Timothy P. Clackson ◽  
Verity A Saunders ◽  
Timothy P Hughes

Abstract Abstract 2745 Ponatinib is a potent pan-BCR-ABL tyrosine kinase inhibitor (TKI) currently in a pivotal phase 2 clinical trial. Ponatinib (PON) was specifically designed to target both native and all mutant forms of BCR-ABL, including T315I. The phase I study of oral ponatinib in patients with refractory CML/ALL or other hematologic malignancies recently reported that 66% and 53% of patients with CP-CML achieved MCyR and CCyR respectively (Cortes et al., ASH 2011 abstract #210). While extensive modelling experiments in BaF3 cells have been performed characterising in vitro response to ponatinib, little is known about the interactions of this drug and drug transporters that impact the response of other tyrosine kinase inhibitors (TKIs). To explore this we have examined both the degree of in vitro kinase inhibition mediated by ponatinib in BCR-ABL+ cell lines, and the intracellular uptake and retention (IUR) of ponatinib achieved. The IC50 was determined by assessing the reduction in %p-Crkl in response to increasing concentrations of ponatinib in vitro. The IUR assay was performed as previously using [14-C]-ponatinib. To determine the role of ABCB1 and ABCG2, both previously implicated in the transport of other TKIs, IC50 analysis was performed on K562 cells, and variants; ABCB1 overexpressing K562-DOX and ABCG2 overexpressing K562-ABCG2. As shown in Table 1, in contrast to the results previously observed with imatinib (IM), nilotinib (NIL) and dasatinib (DAS) there was no significant difference in the IC50ponatinib between these three cell lines, suggesting neither ABCB1 nor ABCG2 play a major role in ponatinib transport. Furthermore, the addition of either the ABCB1 and ABCG2 inhibitor pantoprazole, or the multidrug resistance (MDR) inhibitor cyclosporin did not result in a significant change in the IC50ponatinib in any of the cell lines tested. In contrast the addition of either pantoprazole or cyclosporin resulted in a significant reduction in IC50IM, IC50NIL. and IC50DAS of K562-DOX cells, supporting the notion that these TKIs interact with ABCB1.Table 1:The IC50 of ponatinib (compared to IM, NIL and DAS) in K562 cells and the over-expressing variants DOX and ABCG2 in the presence of the ABC inhibitors pantoprazole and cyclosporin. n=5. *p<0.05IC50% reduction in IC50+ pantoprazole+ cyclosporinPON (nM)IM (μM)NIL (nM)DAS (nM)PONIMNILDASPONIMNILDASK5627.793751111544*NA−107NA2DOX7.919*598*100*1018*63*1655*88*ABCG26.4730025*6NA To further examine the effect of ABC transporters on ponatinib efflux we have determined the IUR of [14-C]-ponatinib in K562, DOX and ABCG2 cell lines. We demonstrate no significant difference in the IUR between these cell lines at 37°C (n=6) (K562 vs DOX p=0.6; K562 vs ABCG2 p=0.37 and DOX vs ABCG2 p=0.667 at 2uM respectively). Temperature dependent IUR experiments reveal a significant reduction in the ponatinib IUR at 4°C compared to 37°C in K562 cells (n=6) (p=0.008), DOX cells (p=0.004) and ABCG2 cells (p=0.002) supporting the likely involvement of an ATP/temperature dependent, and yet to be determined, component of ponatinib influx. There was no significant difference in the IUR between these cell lines at 4°C (p=0.824, p=0.7 and p=0.803 respectively). Importantly, these data are consistent with the IC50ponatinib findings. If ATP dependent efflux pumps (ABCB1 and ABCG2) were actively transporting ponatinib, a significant decrease in IUR in DOX and ABCG2 at 37°C compared to K562 cells would be expected, but is not observed here. Analysis of ponatinib IUR in the prototypic ABCB1 over-expressing CEM-VBL100 cells, and their parental, ABCB1 null counterparts (CCRF-CEM) further confirmed these findings. The IUR in VBL100 cells was significantly higher than that observed in CEM's (p<0.001; n=5), providing further evidence that ponatinib was not being exported from the cell actively via ABCB1. These data suggest that the transport of ponatinib is, at least in part, temperature-dependent indicating a yet to be determined ATP transporter may be involved in the transport of ponatinib into leukaemic cells. Importantly, this data suggests that ponatinib is unlikely to be susceptible to resistance via the major ATP efflux transporters (ABCB1 or ABCG2) that have been previously demonstrated to significantly impact the transport of, and mediate resistance to other clinically available TKIs. Disclosures: White: BMS: Honoraria, Research Funding; Novartis Pharmaceuticals: Honoraria, Research Funding. Clackson:ARIAD: Employment. Hughes:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; ARIAD: Honoraria, Membership on an entity's Board of Directors or advisory committees.


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