scholarly journals The SIX1 homeobox Gene Is a Novel Therapeutic Target in CALM-AF10 Leukemogenesis

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 38-39
Author(s):  
Waitman K. Aumann ◽  
Catherine P. Lavau ◽  
Amanda Harrington ◽  
Donald Tope ◽  
Amanda E. Conway ◽  
...  
Keyword(s):  
Therapeutic Target ◽  
Nuclear Export ◽  
Homeobox Gene ◽  
Leukemia Cells ◽  
Hematopoietic Progenitors ◽  
Self Renewal ◽  
Downstream Targets ◽  
Hoxa Genes ◽  
Novel Therapeutic

Background : The CALM-AF10 translocation is found 5-10% of T-cell acute lymphoblastic leukemias (T-ALL), and a subset of acute myeloid leukemias (AML). CALM-AF10 leukemias are characterized by elevated expression of proleukemic HOXA genes. Since HOXA genes are difficult to target, we hypothesized that identification of non-HOXA CALM-AF10 effector genes could potentially yield novel therapeutic targets. To discover novel CALM-AF10-regulated genes, we took advantage of our prior observation that the nuclear export factor CRM1/XPO1 tethers CALM-AF10 to HOXA genes by interacting with a nuclear export signal within CALM. Using microarrays, we identified a set of genes that showed decreased expression in response to the CRM1 inhibitor, Leptomycin B (LMB), similar to Hoxa genes, in murine CALM-AF10 leukemia cells. Then using RNA-sequencing, we discovered a set of genes increased in murine hematopoietic stem cells transduced with CALM-AF10. There were 11 genes that were both decreased in response to LMB and increased in response to CALM-AF10, which included the Hoxa gene cluster, as well as Six1. Similar to HOXA genes, SIX1 is a homeobox gene that is associated with embryogenesis and is quiescent post-embryologically. Additionally, SIX1 and its cofactor EYA2 have been found to be overexpressed in numerous solid tumors, and inhibitor of the SIX1/EYA2 complex has recently been described. While there is evidence of a role for SIX1 in solid tumors, its role in leukemias has not been explored. Objective: To evaluate the role of SIX1 in CALM-AF10 leukemias. Design/Methods: RT-qPCR and Chromatin Immunoprecipitation (ChIP) were performed using bone marrow progenitors transduced with CALM-AF10 or an empty vector, with and without LMB. Methylcellulose colony assays assessed the ability of SIX1 to enhance self-renewal of hematopoietic progenitors. An inhibitor of the Six1/Eya2 interaction (compound 8430) was used to evaluate cell proliferation. Downstream targets of Six1 were evaluated using RT-qPCR in CALM-AF10 cells treated with Six1/Eya2 inhibitor (8430). Results: RT-qPCR confirmed overexpression of SIX1 in CALM-AF10 leukemia cells, and showed decreased SIX1 expression in the presence of LMB. Furthermore, ChIP revealed that CALM-AF10 binds to the SIX1 gene locus. Overexpression of SIX1 in fetal liver progenitors was sufficient to increase self-renewal potential. The 8430 Six1/Eya2 inhibitor slowed cell growth in CALM-AF10 cells compared to cells treated with DMSO alone. Finally, downstream targets such as Slc2a1, Cdk2, and Cyclina2 were decreased in 8430-treated CALM-AF10 leukemia cells. Conclusions: The SIX1 homeobox gene is highly expressed during embryogenesis, and its expression is silenced post-embryogenesis. Through an initial unbiased screen, we discovered that Six1 may play a role in CALM-AF10 leukemogenesis. We have determined that Six1 expression is upregulated in the presence of CALM-AF10. Further, we have shown a potential oncogenic role for Six1, as it was able to increase the self-renewal potential of hematopoietic progenitors. The role of Six1 in CALM-AF10 leukemia is further supported by the ability of a SIX1/EYA2 inhibitor to slow the growth of CALM-AF10 leukemia cells and decrease the expression of downstream targets of SIX1. These observations suggest that Six1 plays a pathogenic role in leukemogenesis, and may be a novel therapeutic target in CALM-AF10 leukemias. Disclosures No relevant conflicts of interest to declare.

scholarly journals SIX1 Is a Novel Effector Gene in CALM-AF10 Leukemia

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5035-5035
Author(s):  
Waitman K. Aumann ◽  
Catherine P. Lavau ◽  
Amanda Harrington ◽  
Amanda E. Conway ◽  
Daniel S. Wechsler
Keyword(s):  
Nuclear Export ◽  
Conflicts Of Interest ◽  
Fetal Liver ◽  
Critical Role ◽  
Leukemia Cell ◽  
The Self ◽  
Hek293 Cells ◽  
Hematopoietic Progenitors ◽  
Self Renewal ◽  
Hoxa Genes

Background: The CALM-AF10 translocation is detected in ~10% of T-cell acute lymphoblastic leukemias (T-ALLs), and in some acute myeloid leukemias (AMLs). CALM-AF10 leukemias are characterized by high expression of proleukemic HOXA genes, which serve a critical role in hematopoiesis. We hypothesized that identification of novel CALM-AF10 effector genes may yield new therapeutic targets in this difficult to treat leukemia. We took advantage of our prior observation that the nuclear export factor CRM1/XPO1 tethers CALM-AF10 to HOXA genes by interacting with a nuclear export signal (NES) in CALM. Using next generation sequencing, we determined that, SIX1, similar to HOXA genes, is increased in CALM-AF10 leukemias and decreased in response to CRM1 inhibition with Leptomycin B (LMB). Design/Methods: RT-qPCR and Chromatin Immunoprecipitation were performed using both bone marrow progenitors and murine embryonic fibroblasts (MEFs) transduced with CALM-AF10 or an empty vector, with and without LMB. The ability of SIX1 to enhance self-renewal of hematopoietic progenitors was examined by measuring the colony-forming ability of transduced fetal liver hematopoietic progenitor cells. CRISPR-Cas9 was used to silence SIX1 in Human Embryonic Kidney 293 (HEK293) cells. Results: RT-qPCR confirmed overexpression of SIX1 in both CALM-AF10 transduced MEFs and CALM-AF10 leukemias, with decreased SIX1 expression observed in the presence of LMB. ChIP analysis showed that CALM-AF10 binds to the SIX1 gene locus. Overexpression of SIX1 in fetal liver cells was sufficient to increase the self-renewal potential of colony-forming progenitors. SIX1 was successfully knocked out in HEK293 cells without a significant effect on HEK293 proliferation. Conclusions: The SIX1 homeobox gene is highly expressed during development and its expression is silenced post-embryogenesis. Increased SIX1 expression has been reported in numerous solid tumors. We have determined that SIX1 is upregulated in CALM-AF10 leukemias, and increases the self-renewal potential of hematopoietic progenitors. Using CRISPR-Cas9 to silence SIX1, we have demonstrated that SIX1 is not essential for cell survival, and that its inhibition may impair CALM-AF10 leukemia cell proliferation. Thus, SIX1 may play a pathogenic role in leukemogenesis and is a potential therapeutic target in CALM-AF10 leukemias. Disclosures No relevant conflicts of interest to declare.

scholarly journals A SIX1/EYA2 Inhibitor Impairs CALM-AF10 and Jurkat Leukemia Cell Proliferation

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4331-4331
Author(s):  
Waitman Kurt Aumann ◽  
Catherine P. Lavau ◽  
Dongdong Julie Chen ◽  
Amanda E. Conway ◽  
Heide Ford ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Lines ◽  
Nuclear Export ◽  
Leukemia Cell ◽  
Homeobox Gene ◽  
Jurkat Cells ◽  
Leukemia Cells ◽  
Leukemia Cell Lines ◽  
Gene And Protein Expression ◽  
Hoxa Genes

Abstract Background : The CALM-AF10 translocation is found in 5-10% of T-cell acute lymphoblastic leukemias (T-ALL), and a subset of acute myeloid leukemias (AML). CALM-AF10 leukemias are characterized by elevated expression of proleukemic HOXA genes. Since HOXA genes are difficult to target, we hypothesized that identification of non-HOXA CALM-AF10 effector genes could potentially yield novel therapeutic targets. To discover novel CALM-AF10-regulated genes, we took advantage of our prior observation that the nuclear export factor CRM1/XPO1 tethers CALM-AF10 to HOXA genes by interacting with a nuclear export signal within CALM. Using microarrays, we identified a set of genes that showed decreased expression in response to the CRM1 inhibitor Leptomycin B (LMB), similar to Hoxa genes, in murine CALM-AF10 leukemia cells. Then using RNA-sequencing, we discovered a set of genes increased in murine hematopoietic stem cells transduced with CALM-AF10. There were 11 genes that were both decreased in response to LMB and increased in response to CALM-AF10, which included the Hoxa gene cluster, as well as Six1. We demonstrated that CALM-AF10 increases Six1 expression and localizes to the Six1 locus, as it does the Hoxa genes. SIX1, like the Hoxa genes, is a homeobox gene that is associated with embryogenesis and is quiescent post-embryologically. In addition, SIX1 and its cofactor EYA2 are overexpressed in numerous solid tumors, and an inhibitor of the SIX1/EYA2 complex (Compound 8430) has recently been described. While there is evidence of a role for SIX1 in solid tumors, its role in leukemias has not been explored. Objective : Evaluate the effect of a SIX1/EYA2 complex inhibitor on leukemia cell proliferation. Design/Methods : SIX1 gene and protein expression were assessed in CALM-AF10, Jurkat (T-ALL) and NOMO1 (AML) leukemia cell lines via Western Blot and RT-qPCR. CALM-AF10 leukemias were derived from murine models in our lab, Jurkat and NOMO1 cell lines were obtained from ATCC. The effect of compound 8430 - an inhibitor of the Six1/Eya2 interaction - on cell proliferation was evaluated using Cell-Titer-Glo Assays and liquid culture proliferation assays. In addition, we used the the CRM1 Nuclear Export Inhibitor KPT-330 alone and in combination with 8430 in these cell lines. SynergyFinder2 (https://synergyfinder.fimm.fi/) was used to assess synergy of 8430 and KPT-330. δ-score is a calculated value that indicates synergistic drug interaction, with a higher δ-score indicative of a synergistic effect of the drugs. Results : SIX1 gene and protein expression are increased in CALM-AF10 leukemia cell lines and Jurkat T-ALL cells, but not NOMO1 cells. Compound 8430 decreases cell proliferation in CALM-AF10 leukemias and Jurkat leukemia cell lines, however it did not affect the AML line NOMO1. Correspondingly, liquid cultures showed that 8430 alone slowed the proliferation of CALM-AF10 leukemia and the Jurkat cells, but not NOMO1 cells. The addition of KPT-330 to 8430 was synergistic in CALM-AF10 leukemia cells with a KPT-330 dose of 60 nM and multiple dose levels of 8430 (δ-scores 17-19) while in the Jurkat leukemia cells a dose of 30 nM of KPT-330 was synergistic at multiple dose levels of 8430 (δ-score 6-8) (Figure 1). Conclusions : The SIX1 homeobox gene is highly expressed during development, and its expression is silenced post-embryogenesis. Through an initial unbiased screen, we discovered that Six1 may play a role in CALM-AF10 leukemogenesis. We have determined that Six1 expression is upregulated in the presence of CALM-AF10. A role for Six1 in CALM-AF10 leukemogenesis is further supported by the ability of a SIX1/EYA2 inhibitor to slow the proliferation of CALM-AF10 leukemia cells. Importantly, based on our observation that 8430 slows proliferation of Jurkat cells, SIX1 inhibition may be relevant in other leukemias. Finally, our demonstration that 8430 synergizes with KPT-330, a Nuclear Export Inhibitor, suggests the possibility of a novel therapeutic approach for CALM-AF10 and other leukemias. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

scholarly journals Targeting NMNAT1 in Acute Myeloid Leukemia

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 879-879
Author(s):  
Xiangguo Shi ◽  
Daisuke Nakada ◽  
Ayumi Kitano ◽  
Rebecca Murdaugh ◽  
Yu-Jung Tseng ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Therapeutic Target ◽  
Myeloid Leukemia ◽  
Leukemia Cells ◽  
Chemotherapy Treatment ◽  
Normal Cells ◽  
Nad Biosynthesis ◽  
Acute Myeloid ◽  
Novel Therapeutic

Acute myeloid leukemia (AML) is primarily a disease of older adults with poor treatment outcomes. Despite years of intensive research, the standard induction therapy for AML has remained largely unchanged for decades. Thus, the development of new and efficacious therapeutic targets for AML is urgently needed. Leukemia cells exhibit multiple metabolic aberrations that may be therapeutically targeted. Here, we show that nicotinamide adenine dinucleotide (NAD+) promotes leukemogenesis and causes chemotherapy treatment resistance through fueling energetic metabolism, and pinpoints nicotinamide nucleotide adenylyltransferase 1 (NMNAT1) is a novel therapeutic target for AML. To identify novel genes essential for AML, we performed a whole genome CRISPR dropout screen by using MOLM13 cell line and identified 1,951 essential genes (Fig. A). By searching druggable targets among these genes, we narrowed down to 345 genes, among which we found two genes, NMNAT1 (nicotinamide nucleotide adenylyltransferase 1) and NAMPT (nicotinamide phosphoribosyltransferase), both involved in key steps in NAD+ biosynthesis. We comprehensively analyzed dependency scores for all genes involved in the NAD+ biosynthetic pathways (de novo synthesis pathway, the Preiss-Handler pathway and the salvage pathway) across a broad panel of cancer cell lines from the Dependency Map database (https://depmap.org/portal/). The results showed that NMNAT1 and NAMPT are both strongly selective and uniquely required for hematological malignancies compared to other cancers (Fig. B). Since little success has been achieved for NAMPT inhibitors in clinical trials, our attention was drawn to NMNAT1, which encodes a nuclear localized enzyme catalyzing the final step in NAD+ biosynthesis. We confirmed that deletion of NMNAT1 in AML cells significantly reduced nuclear NAD+ level and cell viability over time while sparing normal hematopoietic progenitor cells, suggesting that NMNAT1 is targetable to AML. Overexpression of wild-type Nmnat1 but not the enzymatically inactive forms rescued NMNAT1-KO AML, indicating that the catalytic activity of NMNAT1 is required for AML. To study the role of NAD+ in AML, we first measured NAD+ levels in leukemic and normal cells, and found higher NAD+ levels in leukemia-initiating cells from a murine MLL-AF9-induced AML model compared to normal cells. Supplementation of NAD+ metabolites (NMN, NAM and NR) increased AML proliferation, enhanced glycolysis (lactate production) and oxidative phosphorylation (ATP production), resulting in chemotherapy resistance (Fig. C). Deletion of NMNAT1 sensitized AML cell to chemotherapy treatment. To study the role of NMNAT1 in leukemogenesis in vivo, we genetically deleted NMNAT1 in murine or human leukemia cells, transplanted them into recipient mice, and found that deletion of NMNAT1 reduced leukemic burden and extended leukemia-free survival (Fig. D). Finally, to reveal the molecular mechanisms underlying NMNAT1 KO-mediated cell death (increased levels of gamma-H2AX), RNA-seq and functional assay of NAD+ dependent enzymes were performed. We found that the reduction of nuclear NAD+ resulting from NMNAT1 deletion upregulated genes involved in DNA repair pathway, which may be linked to impaired PARPs and Sirtuins activity. Our findings reveal the important function of NAD+ in leukemogenesis and chemoresistance, and identify NMANT1 as a novel therapeutic target for AML. Figure Disclosures No relevant conflicts of interest to declare.

Nuclear Export as a Novel Therapeutic Target: The CRM1 Connection

2015 ◽  
Vol 15 (7) ◽  
pp. 575-592 ◽  
Author(s):  
Chuanwen Lu ◽  
Jose Figueroa ◽  
Zhongwei Liu ◽  
Venu Konala ◽  
Amardeep Aulakh ◽  
...  
Keyword(s):  
Therapeutic Target ◽  
Nuclear Export ◽  
Novel Therapeutic

Molecular Interactions of α-Synuclein, Mitochondria, and Cellular Degradation Pathways in Parkinson's Disease

2020 ◽  
pp. 212-234
Author(s):  
Mansi Verma ◽  
Sujata Basu ◽  
Manisha Singh ◽  
Rachana R. ◽  
Simrat Kaur ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Molecular Interactions ◽  
Therapeutic Target ◽  
Molecular Mechanisms ◽  
Degradation Pathways ◽  
Functional Changes ◽  
The World ◽  
Novel Therapeutic

Parkinson's disease (PD) has been reported to be the most common neurodegenerative diseases all over the world. Several proteins are associated and responsible for causing PD. One such protein is α-synuclein. This chapter discusses the role of α-synuclein in PD. Various genetic and epigenetic factors, which cause structural and functional changes for α-synuclein, have been described. Several molecular mechanisms, which are involved in regulating mitochondrial and lysosomal related pathways and are linked to α-synuclein, have been discussed in detail. The knowledge gathered is further discussed in terms of using α-synuclein as a diagnostic marker for PD and as a novel therapeutic target for the same.

scholarly journals Role of Dimerized C16orf74 in Aggressive Pancreatic Cancer: A Novel Therapeutic Target

2019 ◽  
Vol 19 (1) ◽  
pp. 187-198 ◽  
Author(s):  
Toshihiro Kushibiki ◽  
Toru Nakamura ◽  
Masumi Tsuda ◽  
Takahiro Tsuchikawa ◽  
Koji Hontani ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Therapeutic Target ◽  
Novel Therapeutic

scholarly journals The Role of DLLs in Cancer: A Novel Therapeutic Target

2020 ◽  
Vol Volume 13 ◽  
pp. 3881-3901 ◽  
Author(s):  
Meng-Xi Xiu ◽  
Yuan-Meng Liu ◽  
Bo-hai Kuang
Keyword(s):  
Therapeutic Target ◽  
Novel Therapeutic

Flt3/ITD Blocks Myeloid Differentiation Of Hematopoietic Cells By Up-Regulating Runx1

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3808-3808
Author(s):  
Tomohiro Hirade ◽  
Mariko Abe ◽  
Chie Onishi ◽  
Seiji Yamaguchi ◽  
Seiji Fukuda
Keyword(s):  
Conflicts Of Interest ◽  
Hematopoietic Cells ◽  
Cell Number ◽  
Dominant Negative ◽  
Leukemia Cells ◽  
Myeloid Differentiation ◽  
Differentiation And Proliferation ◽  
Runx1 Expression ◽  
Novel Therapeutic

Abstract Internal-Tandem-Duplication mutations in the FLT3 (FLT3/ITD) gene are detected in 30% of patients with acute myeloid leukemia (AML) and are associated with extremely poor prognoses. The lack of significant efficacy of FLT3/ITD inhibitors underscores the need to identify FLT3/ITD-specific signaling pathways that are distinct from those that occur in normal hematopoietic cells to develop novel therapeutic approaches. FLT3/ITD is classified as a “class I mutation” that drives the proliferation of leukemia cells. In addition to mutation of FLT3/ITD, a “class II mutation” that blocks differentiation of the pre-leukemic clone is generally required for the development of AML. For instance, dominant negative mutations of RUNX1 are occasionally found in patients with AML. These mutations of RUNX1 cause AML by blocking the differentiation of leukemia cells in combination with the mutation of FLT3/ITD. RUNX1 is a core-binding transcription factor and plays an important role in hematopoietic homeostasis, particularly differentiation and proliferation. Loss of RUNX1 blocks hematopoietic differentiation and is associated with the emergence of a primitive hematopoietic compartment, suggesting that RUNX1 generally induces differentiation of hematopoietic cells. However, the functional role of RUNX1 as a down-stream effector of FLT3/ITD has not been characterized. Herein, we investigated the role of Runx1 in aberrant proliferation and differentiation of hematopoietic cells induced by Flt3 /ITD. A comparison of RUNX1 expression levels in AML patients for whom information has been deposited in the public gene expression profile database (GSE1159) revealed that RUNX1 mRNA expression was significantly higher in FLT3/ITD+AML cells (N=78) than in FLT3/ITD-AML cells (N=190, P<0.05). The mRNA microarray analysis consistently demonstrated that Runx1 is up-regulated by Flt3/ITD in Ba/F3 cells. Up-regulation of Runx1 by Flt3/ITD was validated in Ba/F3 cells and 32D cells by quantitative RT-PCR. Incubation of control 32D cells with 20 ng/ml of G-CSF increased the number of Gr-1+/Mac-1+cells, whereas the induction of myeloid differentiation by G-CSF was abrogated by the overexpression of Flt3/ITD in 32D cells. By contrast, transduction of shRNA specific for Runx1 into Flt3/ITD+32D cells inhibited the expression of Runx1 mRNA by 60 % but increased the number and the proportion of Gr-1+/Mac-1+cells ; these effects were enhanced by incubation with G-CSF. These data indicate that Runx1 mediates the block of differentiation toward the myeloid lineage that is induced by Flt3/ITD. Moreover, the number of colony-forming units (CFU) over-expressing Flt3/ITD cultured in the absence of growth factors was reduced by Runx1-shRNA without affecting the total cell number in the suspension culture, as compared to Flt3/ITD+32D cells transduced with control-shRNA. This implies that antagonizing Runx1 facilitates the production of terminally differentiated cells that have lost colony-forming ability, thereby reducing the CFU number without altering the total number of cells. Finally, Runx1-shRNA inhibited the formation of secondary CFU colonies derived from the primary Flt3-ITD-over-expressing CFU colonies. Our results suggest that Flt3/ITD blocks myeloid differentiation of Flt3/ITD+cells by up-regulating Runx1 expression. The blocking of differentiation mediated by Runx1 in Flt3/ITD+cells is in contrast to the cell differentiation-inducing role of Runx1 in normal hematopoiesis, suggesting that the function of Runx1 in Flt3/ITD+cells may be distinct from that in normal cells. The reduction of secondary CFU colonies by Runx1-shRNA suggests that Runx1 may mediate self-renewal of Flt3/ITD+hematopoietic progenitor cells. These findings suggest that antagonizing RUNX1 may represent a novel therapeutic strategy to induce terminal differentiation of FLT3/ITD+AML cells in AML patients, in addition to inhibiting their aberrant proliferation. Disclosures: No relevant conflicts of interest to declare.

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