Enhancing the Therapeutic Potential of an Anti-Leukemic Peptide.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 245-245
Author(s):  
Christine M. Palermo ◽  
William C. Wimley ◽  
Charles S. Hemenway
Keyword(s):  
Amino Acids ◽  
High Throughput ◽  
Therapeutic Potential ◽  
Colorimetric Assay ◽  
Lymphoblastic Leukemia ◽  
Genetic Locus ◽  
Chimeric Protein ◽  
Peptide Sequence ◽  
Leukemia Cells ◽  
Hematopoietic Stem

Abstract Despite ongoing success in the treatment of childhood acute lymphoblastic leukemia (ALL), patients harboring translocations involving the genetic locus 11q23 continue to have a poor prognosis. The majority of 11q23 translocations result in the formation of a functional fusion protein consisting of the N-terminus of MLL fused to the C-terminal portion of one of more than 30 fusion partners. This translocation results in a functional chimeric protein critical for leukemogenesis. Recently, our lab has identified an interaction between two common MLL fusion partners, AF4 and AF9. Through a series of mapping experiments we identified a small region of human AF4 to be sufficient for its interaction with AF9. Based on these studies, a synthetic peptide (PFWT) that mimics the AF9 binding site on AF4 was developed. Treatment of leukemia cells that express the MLL-AF4 protein with PFWT results in apoptosis with no observable affects on CD34+ hematopoietic stem cells, suggesting the AF9-AF4 interaction is a promising chemotherapeutic target. To improve upon the therapeutic potential of PFWT, we developed a high-throughput enzyme-linked colorimetric assay to identify peptidomimetics that block the AF9-AF4 interaction. A combinatorial peptide library was synthesized in which each position of the 10-mer sequence was substituted with either the α- or corresponding β-amino acid. β-Amino acids which are similar to α-amino acids but contain an additional carbon in their backbone were chosen because of their resistance to proteases (210= 1024 possible unique sequences). To date, 30 of the peptides screened compare favorably with PFWT for disrupting the AF4-AF9 interaction. Sequencing of the peptides by MS/MS revealed substitutions at the N- and C-terminal ends are well tolerated. In addition, peptides can incorporate as many as three β-amino acids and still retain biological activity. These data are important for establishing a sequence with improved pharmacokinetic properties as compared to PFWT and serve as the first step in our design towards an optimal peptide sequence for drug development. They also validate the utility of a high-throughput assay system for drug screening. Future studies for the identified peptides include determining their biological half-lives, AF9 binding affinities, and ability to induce apoptosis in leukemia cells.

scholarly journals Structure-Microbicidal Activity Relationship of Synthetic Fragments Derived from the Antibacterial α-Helix of Human Lactoferrin

2009 ◽  
Vol 54 (1) ◽  
pp. 418-425 ◽  
Author(s):  
L. Håversen ◽  
N. Kondori ◽  
L. Baltzer ◽  
L. Å. Hanson ◽  
G. T. Dolphin ◽  
...  
Keyword(s):  
Amino Acids ◽  
Therapeutic Potential ◽  
Peptide Sequence ◽  
Activity Relationship ◽  
Human Lactoferrin ◽  
Alanine Scanning ◽  
Microbicidal Activity ◽  
Test Organisms ◽  
Α Helix ◽  
Relationship Of

ABSTRACT There is a need for new microbicidal agents with therapeutic potential due to antibiotic resistance in bacteria and fungi. In this study, the structure-microbicidal activity relationship of amino acid residues 14 to 31 (sequence 14-31) from the N-terminal end, corresponding to the antibacterial α-helix of human lactoferrin (LF), was investigated by downsizing, alanine scanning, and substitution of amino acids. Microbicidal analysis (99% killing) was performed by a microplate assay using Escherichia coli, Staphylococcus aureus, and Candida albicans as test organisms. Starting from the N-terminal end, downsizing of peptide sequence 14-31 showed that the peptide sequence 19-31 (KCFQWQRNMRKVR, HL9) was the optimal length for antimicrobial activity. Furthermore, HL9 bound to lipid A/lipopolysaccharide, as shown by neutralizing endotoxic activity in a Limulus assay. Alanine scanning of peptide sequence 20-31 showed that Cys20, Trp23, Arg28, Lys29, or Arg31 was important for expressing full killing activity, particularly against C. albicans. Substituting the neutral hydrophilic amino acids Gln24 and Asn26 for Lys and Ala (HLopt2), respectively, enhanced microbicidal activity significantly against all test organisms compared to the amino acids natural counterpart, also, in comparison with HL9, HLopt2 had more than 10-fold-stronger fungicidal activity. Furthermore, HLopt2 was less affected by metallic salts than HL9. The microbicidal activity of HLopt2 was slightly reduced only at pH 7.0, as tested in the pH range of 4.5 to 7.5. The results showed that the microbicidal activity of synthetic peptide sequences, based on the antimicrobial α-helix region of LF, can be significantly enhanced by optimizing the length and substitution of neutral amino acids at specific positions, thus suggesting a sequence lead with therapeutic potential.

scholarly journals Autophagy Collaborates with Ubiquitination to Down-Regulate Oncoprotein E2A/Pbx1 in B Cell Acute Lymphoblastic Leukemia

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 5276-5276 ◽  
Author(s):  
Suping Zhang ◽  
Lin Song ◽  
Na Yuan ◽  
Weiwei Lin ◽  
Yan Cao ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Mouse Model ◽  
B Cell ◽  
Western Blotting ◽  
Degradation Mechanism ◽  
Lymphoblastic Leukemia ◽  
Leukemia Cells ◽  
Hematopoietic Stem ◽  
Treatment Groups ◽  
Cell Acute Lymphoblastic Leukemia

Abstract Background: B cell acute lymphoblastic leukemia (B-ALL) accounts for the most cancer incidences in children. The t(1;19) translocation leukemia accounts for a quarter of pre-B ALL and up to 5% of all ALL patients, in which the transcriptional activator E2A and homeobox pre-B-cell leukemia transcription factor 1 (PBX1) fuses, resulting in expression of the chimeric transcription factor E2A/PBX1. E2A/PBX1 has been proved to be an oncogene and could induce malignant transformation. Methods: (1) Childhood B-ALL patients were collected and the stem/progenitor cells (CD34+CD38-) and leukemia cells (CD19+) were sorted with BD FACS Aria III. The autophagy level in these cells was measured by real-time Q-PCR, including gene expression of Beclin1, Atg7, Atg5, LC3 and p62. Normal bone marrow cells from healthy donors were used as control. (2) E2A/PBX1 fusion gene positive pre-B ALL 697 cells were used to establish leukemia mouse model and the autophagy activity in the mice was enhanced by administration of rapamycin. Mice were sacrificed three weeks post treatment, leukemia phenotype was then identified and E2A/PBX1 oncoprotein of liver was detected by western blotting. (3) Autophagy and ubiquitination were manipulated with inhibitors or starvation in 697 cells and the degradation mechanism of E2A/PBX1 was explored. Co-localization of E2A/PBX1-LC3 and E2A/PBX1-Ub was observed by confocal microscopy and quantified by Amnis image flow cytometry. Results: (1) B-ALL primary cells from childhood patients show down-regulated level of autophagy. (2) The NOD-SCID mouse model study shows that activating autophagy of mice by rapamycin improved the survival of leukemia animals, prevented leukemiagenesis by inhibition on the transplanted leukemia cells (examined by blood cell counting, liver HE staining and expression of CD 45, 10, 19 from transplanted human 697 cells by flow cytometry), promoted the degradation of oncoprotein E2A/PBX1 (by Western blotting)), and more importantly, restored hematopoietic stem cells (LSKCD34- cell number detected by flow cytometry). (3) The ALL 697 cell line study shows that activation of autophagy by rapamycin and starvation could down-regulate E2A/PBX1 expression detected by flow cytometry and western blotting. The confocal microscopic results show co-localization of E2A/PBX1 with autophagy marker GFP-LC3 in both rapamycin and starvation treatment groups. To confirm the degradation mechanism, autophagy inhibitor (3-MA or Baf-A1) and ubiquitin-proteasome inhibitor (MG132) were used to treat 697 cells. The results show that inhibition of autophagy in the early stage by 3-MA fails to degrade E2A/PBX1 in 697 cells, but ubiquitination also contributes to the degradation of E2A/PBX1. Quantitative analysis shows increased co-localization percentage of E2A/PBX1-LC3 in rapamycin and starvation treatment groups and increased co-localization of E2A/PBX1 with Ubiquitin in starvation group; but MG132 treatment inhibited the co-localization of E2A/PBX1-Ub induced by starvation, indicating a collaborative role between autophagy and ubiquitination in the degradation of E2A/PBX1. Conclusions: B-ALL primary cells from patients show low autophagy activity; Autophagy activation fights against B-ALL by inhibition on transplanted leukemia cells, degradation of oncoprotein E2A/Pbx1 and restoration of hematopoietic stem cells in the NOD-SCID B-ALL mouse model; autophagy collaborates with ubiquitination in the degradation of E2A/PBX1 in the 697 cells, thereby proposing a novel strategy for targeted therapy on childhood B-ALL. Disclosures No relevant conflicts of interest to declare.

scholarly journals Comparative Studies of B Cell Precursor ALL Pathogenesis and Translational Biology Using a Conditional E2a-PBX1 Transgenic Mouse Model

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 283-283
Author(s):  
Jesus Duque-Afonso ◽  
Jue Feng ◽  
Florian Scherer ◽  
Zhong Wang ◽  
Michael L. Cleary
Keyword(s):  
B Cell ◽  
Conflicts Of Interest ◽  
Lymphoblastic Leukemia ◽  
Leukemia Cell ◽  
Disease Free Survival ◽  
Leukemia Cells ◽  
Mouse Strains ◽  
Driver Gene ◽  
Hematopoietic Stem

Abstract Pediatric acute lymphoblastic leukemia (ALL) represents a collection of orphan diseases that are defined by their genomic abnormalities. Their genetic diversity and low prevalence serve as major barriers to investigations of their molecular pathogenesis and translational biology. To address this, we have engineered novel mouse strains that conditionally activate and express E2a-PBX1, the fusion oncogene derived from chromosomal translocation t(1;19), present in 5-7% of pediatric ALL. Somatic activation of the oncogene is accomplished by Cre-recombinase expressed under the control of specific B-lineage promoters CD19 or Mb1, or in hematopoietic stem cells using the Mx1 interferon-inducible promoter. The three mouse strains show similar pre-leukemic and leukemic phenotypes. At the time of disease, mice exhibit leukocytosis, anemia and thrombocytopenia as well as lymphadenopathy and hepatosplenomegaly and infiltration of several organs including kidney, lung and central nervous system. Leukemia cell phenotypes (CD117+, CD19+, CD43+, CD45+, CD25+, sIgM-, Bp-1+, CD24+, CD127+, CD79a+ and TdT+) correspond to the phenotypic fraction B-C’ (or pro-B/large pre-B II stage, Basel nomenclature) that is very similar to human E2a-PBX1+ pre-B-ALL. Hence, we detected productive VDJ rearrangements and cytoplasmic heavy chain in 12.5 % of cases, a characteristic of human E2a-PBX1 leukemias. Leukemia incidence varies from 5-50% depending on the Cre driver gene and the median latency is about 10 months in E2a.PBX1/Mb1.Cre and Mx1.Cre lines, suggesting the need for secondary mutations. Whole exome sequencing detected secondary genetic aberrations, which were validated in a larger cohort of leukemias. Spontaneous deletions of Pax5, which are present in ~45% of pediatric ALLs with E2a-PBX1 gene fusions, were found in about 30 % of mouse E2a-PBX1 leukemias. Conditional deletion of Pax5 and E2a-PBX1 expression expanded progenitor B cell subpopulations in healthy 3-months old preleukemic mice. Consequently, Pax5 haplo-insufficiency in mice cooperates with E2a-PBX1 increasing the penetrance and shortening the latency of leukemia, providing the first evidence for cooperative oncogenic effects of Pax5 haplo-insufficiency. Tumor suppressor genes as Trp53 and Cdkn2a/b were inactivated by secondary mutations and deletions, respectively. Additionally, secondary recurrent activating mutations were detected in key signaling pathways such as Ras/Mapk and Jak/Stat on which the leukemia cells are strongly dependent. Furthermore, leukemia cells displayed higher basal levels of phosphorylated pSTAT5 and pAKT, pERK1/2, and were hyper-sensitive to stimulation with IL-7 and thymic stromal lymphopoietin (TSLP) as seen by induction of pSTAT5 and supported growth in colony-forming assays. The JAK1/2 inhibitor ruxolitinib blocked the induction of pSTAT5 by IL-7 and TSLP, inhibited colony formation in vitro, and increased disease-free survival after in vivo treatment. Human E2a-PBX1 primary cells and cell lines showed hypersensitivity to IL-7/pSTAT5 activation compared to other ALL karyotypes and pre-treatment with ruxolitinib blocked induction of pSTAT5 by IL-7. In summary, we have developed conditional transgenic E2a-PBX1 mouse models that consistently develop leukemias that resemble human pre-B-ALL carrying the t(1;19) and identified key cooperating oncogenic pathways. This model provides experimental validation of the multistep pathogenesis for a subset of ALL previously inferred from genomic analyses and provides a platform for comparative mechanistic and preclinical studies. Disclosures No relevant conflicts of interest to declare.

CD24High / FLJ/P1Low Expression Correlates with Bad Prognosis and Shorter Survival in Adult ALL.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1451-1451
Author(s):  
Lionel J. Coignet ◽  
Thimothy Johnson ◽  
Alain Nganga ◽  
Qing Zhang ◽  
Corinna Meyer ◽  
...  
Keyword(s):  
Cell Line ◽  
Myeloid Leukemia ◽  
Lymphoblastic Leukemia ◽  
Active Form ◽  
Mitochondrial Protein ◽  
Chromosomal Translocation ◽  
Genetic Alterations ◽  
Leukemia Cells ◽  
Chromosome Band ◽  
Hematopoietic Stem

Abstract Leukemia is a neoplastic proliferation of cells of hematopoietic origin that arises following somatic mutation in a single hematopoietic stem cell, the progeny of which forms a clone of leukemia cells. Genetic alterations leading to leukemia transformation of a cell are often associated with major alterations of chromosomes that can be detected by studying cells of the leukemic clone in mitosis. One of these alterations is a chromosomal translocation that is often used to identify genes potentially involved in other type of rearrangements such as deletions. Abnormalities of chromosome band 13q14 occur in hematologic malignancies of all lineages and at all stages of differentiation. Unlike other chromosomal translocations, which are usually specific for a given lineage, the chromosomal translocation t(12;13)(p12;q14) has been observed in both B-cell and T-cell precursor acute lymphoblastic leukemia (ALL), in differentiated and undifferentiated acute myeloid leukemia (AML) and in chronic myeloid leukemia at progression to blast crisis (CML-BC). Recently, we have shown the presence of a myeloid- and lymphoid-specific breakpoint cluster regions within chromosome band 13q14 in acute leukemia (Genes Chromosome Cancer 25:222–229,1999). In addition, a new cell line has been established from one of the lymphoid cases, MUTZ5, that carries a single t(12;13) translocation (Leukemia 15:1471–1474, 2001). The molecular characterization of this translocation led to the identification of a new gene, FLJ13639, that is disrupted and lost in the MUTZ5 cell line. This gene shares homologies with the large family of short-chain dehydrogenase reductase (SDR). Furthermore, three transcripts and proteins were found to be differentially expressed for this gene, where P1 is potentially the active form of dehydrogenase, while P2 and P3 are lacking the co-activator site. We report here that one of the consequences of the loss of FLJ13639 is the over-expression of CD24 that appears to provide leukemia cells with a proliferation and invasiveness advantage, as well as a certain degree of chemoresistance. FLJ13639 is a new mitochondrial protein that seems to be important for the respiration and apoptosis processes. In addition, semi-quantitative RT-PCR for CD24 and FLJ13639/P1 was performed in a series of cell lines as well as 29 adult ALL samples at diagnosis. Fifty percent of the samples showed a CD24High / FLJ/P1Low profile whereas the remaining samples showed either a balanced expression or a CD24Low / FLJ/P1High profile. These preliminary data on patient samples indicated a correlation between survival and CD24High / FLJ/P1Low expression profile (p=0.04). The current median time survival for the CD24High / FLJ/P1Low group is 9 months whereas the CD24Low / FLJ/P1High group is 28 months. Therefore, this appears to be a new potential prognostic marker for adult ALL. Figure Figure

Leukemia-Specific Ligands Against Childhood Acute Lymphoblastic leukemia

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3269-3269
Author(s):  
Noriko Satake ◽  
Susmita Sarangi ◽  
Astra Chang ◽  
Bridget McLaughlin ◽  
Ping Zhou ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Conflicts Of Interest ◽  
Lymphoblastic Leukemia ◽  
Childhood Acute Lymphoblastic Leukemia ◽  
Leukemia Cells ◽  
Polystyrene Bead ◽  
Integrin Expression ◽  
Hematopoietic Stem ◽  
Nsg Mice ◽  
Primary Leukemia

Abstract Abstract 3269 The one-bead-one-compound (OBOC) combinatorial library method was invented by Kit Lam to identify cancer cell surface targeting ligands (Peng L et al. Nat. Chem. Biol. 2006, Aina OH et al., Mol. Pharm. 2007). Using this method, LLP2A, a ligand against activated a4b1 integrin, was discovered that targets malignant lymphoma with high affinity and specificity (Peng L et al., Mol Cancer Ther. 2008). We tested whether childhood acute lymphoblastic leukemia (ALL) cells expressed activated a4b1 integrin and bound to LLP2A using primary leukemia cells and leukemia cells engrafted in NOD/SCID/IL2Rg null (NSG) mice. Expression of activated a4b1 integrin was observed in three primary leukemia samples (1 T-ALL, 1 precursor B (preB) ALL, and 1 relapsed preB ALL) by the rainbow beads (color-coded polystyrene bead mixture displaying unique ligands against known receptors such as a4b1, a3b1, avb3, a5b1 integrins (Luo J et al., J. Comb. Chem. 2008). To quantify activated a4b1 integrin expression, primary leukemia cells were analyzed by flow cytometry using biotinylated LLP2A/streptavidin-PE. Nine samples (7 preB ALL and 2 relapsed preB ALL) were analyzed. All samples, except for one relapsed preB ALL sample, showed expression of activated a4b1 integrin at different levels. In order to determine the specificity of activated a4b1 integrin expression, hematopoietic stem cells from three normal bone marrow (BM) samples were analyzed and showed very low levels of activated a4b1 integrin expression. Furthermore, we have identified 32 analogues of LLP2A using three fresh preB ALL samples to screen two LLP2A-focused libraries. Peptide microarrays using a polystyrene slide coated with neutravidin and biotinylated ligands will be prepared with these analogues. We will determine the binding affinity and specificity of these analogues to a series of primary ALL cells. Binding specificity to leukemia cells will be determined by excluding ligands which bind to normal hematopoietic progenitor (CD34) cells. The property of the selected ligands will be tested in vivo using NSG mice engrafted with primary ALL cells. Updated results with these new ligands will be presented at the meeting. Disclosures: No relevant conflicts of interest to declare.

First-in-human clinical trial of the autologous CD7-CART for relapsed/refractory ACUTE lymphoblastic leukemia/lymphoma.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. 3026-3026
Author(s):  
Mingzhi Zhang ◽  
Lin Yang ◽  
Xiaorui Fu ◽  
Lei Zhang ◽  
Huimin Meng ◽  
...  
Keyword(s):  
Clinical Trial ◽  
T Cells ◽  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Therapeutic Potential ◽  
Lymphoblastic Leukemia ◽  
Intensive Chemotherapy ◽  
Open Label ◽  
Hematopoietic Stem ◽  
Malignant T Cells

3026 Background: CD7 represents a potential target for T-cell acute lymphoblastic leukemia/lymphoma (T-ALL/T-LBL). We developed CD7 nanobody derived chimeric antigen receptor T-cells (CD7-CART), and established a non-gene editing strategy by anchoring CD7 in the ER and/or Golgi to overcome the CART fratricide. Methods: This single-arm, open-label, phase I study is to investigate CD7-CART cell manufacturing feasibility without contamination of malignant T cells, and the safety and efficacy of the CART on patients with CD7 positive relapsed/refractory T-ALL/T-LBL. 3 subjects, identified as both CD4 and CD8 negative T-ALL or T-LBL were enrolled. CART cells were manufactured by using CD4+/CD8+ sorted T cells from leukapheresis. All patients (Pts) were pretreated with Flu/Cy prior to CART infusion. 1x106/kg CART cells were given to case 2 and 3, while 1.5x106/kg to case 1. Results: Case 1 was diagnosed as refractory ALL with myeloid differentiation, who had received intensive chemotherapy and allogeneic hematopoietic stem cell microtransplantation. Case 2 was diagnosed as ALL (T/B mixed type) but relapsed with CNS involvement, and received radiotherapy in addition to intensive chemotherapy. Prior to CART infusion, case 2 had no abnormal B cells but 17.69% of abnormal early T cellsfrom BM. Case 3 had stage VI of T-LBL, which recurred after multi-cycle chemotherapy of BFM-90 regimen and autologous SCT. After CART treatment, no neurotoxicity was observed in all pts. Case 1 had grade 3 CRSwhile case 2 and 3 had grade 1, although increased IL-6 was detected in all pts. Significant CART expansion and persistence were observed in case 2 and 3, and MRD negative CR was confirmed on day 28 in both pts. The number of generalized lymphadenopathy, lymph node size, and the degree of metabolism were all significantly reduced in case 3. Case 1 had only moderate CART expansion, but abnormal early T cells from BM decreased from 70.03% to 19.57% on day 30. After CART infusion, the number of peripheral abnormal T cells became either undetectable in case 2 and 3, or significantly decreased in case 1. Interestingly, CART had unsustained effect on normal T cells in all pts. As of Feb-10-2020, case 1 has 5 months of OS, including 3 months of PFS. Case 2 and 3 has reached 2 and 1 months of PFS and is still in remission. Conclusions: CD7-CART cells can be manufactured without contamination of malignant T cells. CD7-CART therapy is well-tolerated and has great therapeutic potential for relapsed/refractory CD7 positive T cell malignancies. Clinical trial information: NCT04004637 .

FLJ/P1 Is a New Mitochondrial Dehydrogenase Important in Respiration and Apoptosis.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4292-4292
Author(s):  
Lionel J. Coignet ◽  
Timothy Johnson ◽  
Alain Nganga ◽  
Pushpankur Ghoshal ◽  
Christiane Houde ◽  
...  
Keyword(s):  
Cell Line ◽  
Myeloid Leukemia ◽  
Expression Profiles ◽  
Lymphoblastic Leukemia ◽  
Active Form ◽  
Chromosomal Translocation ◽  
Genetic Alterations ◽  
Leukemia Cells ◽  
Chromosome Band ◽  
Hematopoietic Stem

Abstract Leukemia is a neoplastic proliferation of cells of hematopoietic origin that arises following somatic mutation in a single hematopoietic stem cell, the progeny of which forms a clone of leukemia cells. Genetic alterations leading to leukemia transformation of a cell are often associated with major alterations of chromosomes that can be detected by studying cells of the leukemic clone in mitosis. One of these alterations is a chromosomal translocation that is often used to identify genes potentially involved in other type of rearrangements such as deletions. Abnormalities of chromosome band 13q14 occur in hematologic malignancies of all lineages and at all stages of differentiation. Unlike other chromosomal translocations, which are usually specific for a given lineage, the chromosomal translocation t(12;13)(p12;q14) has been observed in both B-cell and T-cell precursor acute lymphoblastic leukemia (ALL), in differentiated and undifferentiated acute myeloid leukemia (AML) and in chronic myeloid leukemia at progression to blast crisis (CML-BC). Recently, we have shown the presence of a myeloid- and lymphoid-specific breakpoint cluster regions within chromosome band 13q14 in acute leukemia (Genes Chromosome Cancer 25:222-229,1999). In addition, a new cell line has been established from one of the lymphoid cases, MUTZ5, that carries a single t(12;13) translocation (Leukemia15:1471-1474, 2001). The molecular characterization of this translocation led to the identification of a new gene, FLJ13639, that is disrupted and lost in the MUTZ5 cell line. This gene shares homologies with the large family of short-chain dehydrogenase reductase (SDR). Furthermore, three transcripts and proteins were found to be differentially expressed for this gene, where P1 is potentially the active form of dehydrogenase, while P2 and P3 are lacking the co-activator site. We previously reported that one of the consequences of the loss of FLJ13639 is the over-expression of CD24 that appears to provide leukemia cells with a proliferation and invasiveness advantage, as well as a certain degree of chemoresistance. In addition, data on patient samples indicated a correlation between survival and CD24High/FLJ/P1Low expression profile (Blood 106 (11), Nov 2005). We show that FLJ/P1 is a new mitochondrial protein that is important for the respiration and apoptosis processes. Restoration of the FLJ/P1 function induced CD24 down-regulation, decreased invasive potential as assessed by Matrigel assay and decreased chemoresistance. FLJ/P1 function restoration might represent a new potential therapy, that could, when combined with the assessment of FLJ/P1-CD234 expression profiles, allow the future development of personalized treatment.

Indirubin-3'-Monoxime Induces Apoptosis and Autophagy In Acute Lymphoblastic Leukemia Cells and Chronic Myelogenous Leukemia Cells, Exhibits Limited Cytotoxicity In CD34+ Hematopoietic Stem Cells, Lymphocytes and Granulocytes

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3984-3984
Author(s):  
Ming-Yang Lee ◽  
Yi-Wen Liu ◽  
Ming-Ho Chen ◽  
Jing-Jing Chuang
Keyword(s):  
Stem Cells ◽  
Cell Death ◽  
Acute Lymphoblastic Leukemia ◽  
Hematopoietic Stem Cells ◽  
Cell Survival ◽  
Cytotoxic Effect ◽  
Lymphoblastic Leukemia ◽  
Myelogenous Leukemia ◽  
Leukemia Cells ◽  
Hematopoietic Stem

Abstract Abstract 3984 The rates of treatment-related mortality (TRM) and relapse are unacceptably high in adults undergoing antileukemia treatments for acute lymphoblastic leukemia (ALL). So far has no better therapy with low side effects to improve long-term survival in these patients. Indirubin, a Chinese translational anti-chronic myelogenous leukemia (CML) agent, is able to induce cellular apoptosis. However, until now the functional action of IO on ALL remains still unknown. Therefore, here we investigated and compared the cytotoxic efficacy and action of indirubin-3'-monoxime (IO) in JM1 (ALL cell) and K562 (CML cell). ALL and CML cells were treated with a series of IO dose for 24 and 48h, and cell survival was determined by WST-1 assay. ALL and CML cells were shown to be similar susceptible to IO cytotoxicity. In order to clear in which way of cell death induced by IO, we performed analyses for apoptosis, necrosis and autophagy, respectively. After IO treatment, both ALL and CML cells were arrested in the G2/M cell cycle phase. In addition, an increase of sub-G1 proportion was caused. We found also increasing of caspase-3 activation and formation of cleaved PARP in a dose dependent manner. These were associated with the form of apoptosis. However, the caspase inhibitor Z-VAD-FMK only could partially prevent cell death in ALL and CML cells. When further analyzing the necrotic phenomenon through measuring LDH release, the result clearly showed that LDH release was not remarkable after cell treatment with high dose of IO. Besides, we observed surprisingly in Western blot the increasing expression of microtubule-associated protein light chain 3-II (LC3-II), which generally correlates to formation of autophagosomes. Because better antileukemic drug should not induce toxicity in normal blood cells as much as possible, so the cytotoxic effect of IO in CD34+ hematopoietic stem cells, lymphocytes and granulocytes was analyzed. Excitingly, results showed that IO could not affect cell viability of granulocytes, and IO cytotoxicity in lymphocytes was only marginal. If CD34+ hematopoietic stem cells were treated with IO, the rate of cell survival and their ability of differentiation were almost identical in contrast with non-treated control. Apparently, these data indicated that IO possesses the capability to induce apoptosis and autophagy in both CML and ALL cells. The most important is that the IO hardly influences the cell survival and the differentiation of CD34+ hematopoietic stem cells, the cytotoxic effect in granulocytes and lymphocytes is only limited. In conclusion, IO can be considered as a potential agent for clinical anti- ALL treatment. Disclosures: No relevant conflicts of interest to declare.

Targeting Pre-Leukemic Stem Cells in T-Acute Lymphoblastic Leukemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 527-527
Author(s):  
Bastien Gerby ◽  
Diogo F.T Veiga ◽  
Jana Krosl ◽  
Julianne Ouellette ◽  
André Haman ◽  
...  
Keyword(s):  
Stem Cells ◽  
Acute Lymphoblastic Leukemia ◽  
High Throughput ◽  
High Throughput Screening ◽  
Conflicts Of Interest ◽  
Lymphoblastic Leukemia ◽  
Primary Cells ◽  
Leukemic Stem Cells ◽  
Hematopoietic Stem

Abstract Current chemotherapy of pediatric T cell acute lymphoblastic leukemia (T-ALL) efficiently reduces the tumor mass with, however, undesirable long term consequences and remains ineffective in adolescent and adult T-ALL. Furthermore, relapse can be caused by pre-leukemic stem cells (pre-LSCs) that were spared by current protocols and evolved to malignancy. A distinctive characteristic of pre-LSCs is their critical dependence on interactions with the microenvironment for survival, which guided our strategy to target pre-LSCs using niche-based screening assays. Using transgenic mouse models that closely reproduce the human disease, we showed that the SCL/TAL1 and LMO1 oncogenic transcription factors establish a pre-leukemic state by reprogramming normal pro-T cells into aberrantly self-renewing pre-LSCs (Gerby et al. PloS Genetics, 2014). We now provide direct evidence that pre-LSCs are much less chemosensitive than leukemic blasts to current drugs, due to a distinctive lower proliferative state as assessed by real-time imaging in a competitive assay. We therefore designed a robust protocol for high-throughput screening (HTS) of compounds targeting primary pre-LSCs that are maintained on stromal cells engineered for optimal NOTCH1 activation to mimick the thymic microenvironement. The multiparametric readout takes into account the intrinsic complexity of primary cells to specifically monitor pre-LSCs. We screened a targeted library of 1904 compounds and identified UM0119979 that disrupts both cell autonomous and non-cell autonomous pathways: UM0119979 abrogates pre-LSC viability and self-renewal activity in vivo by specifically inhibiting the translation of MYC, a downstream effector of NOTCH1, and preventing SCL/TAL1 activity. In contrast, normal hematopoietic stem/progenitor cells remain functional. Moreover, in vivo administration of UM0119979 efficiently reduced the leukemia propagating activity of primary human T-ALL samples in xenografted mice. Finally, in addition to SCL-LMO-induced T-ALL, our results reveal a novel possibility of therapeutic intervention in MYC-dependent hematologic malignancies. In summary, our screening assay, built on the genetic dependencies of pre-LSCs, revealed their vulnerabilities to compounds that inhibit both the primary oncogenes and non-cell autonomous pathways triggered by the microenvironment. The results illustrate how recapitulating tissue-like properties of primary cells in high throughput screening is a promising avenue for innovation in cancer chemotherapy. Disclosures No relevant conflicts of interest to declare.

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