scholarly journals Expression of a recombinant FLT3 ligand and its emtansine conjugate as a therapeutic candidate against acute myeloid leukemia cells with FLT3 expression

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Dengyang Zhang ◽  
Yao Guo ◽  
Yuming Zhao ◽  
Liuting Yu ◽  
Zhiguang Chang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Ex Vivo ◽  
Flt3 Ligand ◽  
E Coli ◽  
Drug Conjugate ◽  
Acute Myeloid Leukemia Cells ◽  
Flt3 Expression ◽  
Acute Myeloid

Abstract Background Most patients with acute myeloid leukemia (AML) remain uncurable and require novel therapeutic methods. Gain-of-function FMS-like tyrosine kinase 3 (FLT3) mutations are present in 30–40% of AML patients and serve as an attractive therapeutic target. In addition, FLT3 is aberrantly expressed on blasts in > 90% of patients with AML, making the FLT3 ligand-based drug conjugate a promising therapeutic strategy for the treatment of patients with AML. Here, E. coli was used as a host to express recombinant human FLT3 ligand (rhFL), which was used as a specific vehicle to deliver cytotoxic drugs to FLT3 + AML cells. Methods Recombinant hFL was expressed and purified from induced recombinant BL21 (DE3) E. coli. Purified rhFL and emtansine (DM1) were conjugated by an N-succinimidyl 3-(2-pyridyldithio)propionate (SPDP) linker. We evaluated the potency of the conjugation product FL-DM1 against FLT3-expressing AML cells by examining viability, apoptosis and the cell cycle. The activation of proteins related to the activation of FLT3 signaling and apoptosis pathways was detected by immunoblotting. The selectivity of FL-DM1 was assessed in our unique HCD-57 cell line, which was transformed with the FLT3 internal tandem duplication mutant (FLT3-ITD). Results Soluble rhFL was successfully expressed in the periplasm of recombinant E. coli. The purified rhFL was bioactive in stimulating FLT3 signaling in AML cells, and the drug conjugate FL-DM1 showed activity in cell signaling and internalization. FL-DM1 was effective in inhibiting the survival of FLT3-expressing THP-1 and MV-4-11 AML cells, with half maximal inhibitory concentration (IC50) of 12.9 nM and 1.1 nM. Additionally, FL-DM1 induced caspase-3-dependent apoptosis and arrested the cell cycle at the G2/M phase. Moreover, FL-DM1 selectively targeted HCD-57 cells transformed by FLT3-ITD but not parental HCD-57 cells without FLT3 expression. FL-DM1 can also induce obvious apoptosis in primary FLT3-positive AML cells ex vivo. Conclusions Our data demonstrated that soluble rhFL can be produced in a bioactive form in the periplasm of recombinant E. coli. FL can be used as a specific vehicle to deliver DM1 into FLT3-expressing AML cells. FL-DM1 exhibited cytotoxicity in FLT3-expressing AML cell lines and primary AML cells. FL-DM1 may have potential clinical applications in treating patients with FLT3-positive AML.

scholarly journals FLT3 Ligand-DM1 Conjugate Selectively Targets Acute Myeloid Leukemia Cells with FLT3 Expression

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 30-31
Author(s):  
Dengyang Zhang ◽  
Yao Guo ◽  
Yuming Zhao ◽  
Liuting Yu ◽  
Zhiguang Chang ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Acute Myeloid Leukemia ◽  
Tyrosine Kinase ◽  
Myeloid Leukemia ◽  
Target Cells ◽  
Flt3 Ligand ◽  
Drug Conjugate ◽  
Flt3 Expression ◽  
Acute Myeloid

Acute myeloid leukemia (AML) is a malignant hematopoietic neoplasm featured by impaired differentiation and uncontrolled proliferation of myeloid progenitors. Gain-of-function mutations of FMS-like tyrosine kinase 3 (FLT3) present in 30-40% of patients with AML. In addition, more than 90% of AML blasts aberrantly express FLT3, making FLT3 an attractive therapeutic target for AML. Currently, several small molecule tyrosine kinase inhibitors (TKIs) targeting FLT3 have been approved in the treatment of AML, but they need to be used in combination with chemotherapy because of their limited potency to eliminate leukemic cells as single agents, largely due to the development of secondary inhibitor-resistant FLT3 mutations. Therefore, novel therapeutic strategies targeting FLT3 are needed. In the present study, we developed a FLT3 ligand-emtansine drug conjugate (FL-DM1) that targeted FLT3-positive AML cells with high potency and selectivity. We expressed recombinant human FLT3 ligand (rhFL) in the periplasm of recombinant E. Coli. The protein was purified by a two-step purification system containing Ni-NTA and Phenyl Sepharose. Our purified rhFL was bioactive to stimulate phosphorylation of FLT3 and proliferation of THP-1 cells. Next, we conjugated purified rhFL and emtansine (DM1) with SPDP linker. Reducing and non-reducing SDS-PAGE revealed that rhFL and DM1 were successfully conjugated, evidenced by a band with higher molecular weight of the conjugation product. Previous studies show that DM1 is a drug preferentially targeting proliferating cells by depolymerizing microtubules through binding at the vinca binding site of tubulin. We found that FL-DM1 reserved the physiological function of FLT3 ligand to stimulate proliferation of AML cells by inducing phosphorylation of FLT3 and the downstream signaling protein AKT in immunoblot, potentially enhancing the potency of FL-DM1 to inhibit FLT3-positive AML cells. Furthermore, flow cytometry showed that the surface expression of FLT3 significantly decreased on cells treated by FL-DM1 within two hours, which indicated the internalization of FL-DM1/FLT3 complex on these FLT3-positive AML cells, providing a mechanism of FL-DM1 entering target cells. In cell viability assay, we found that FL-DM1 effectively inhibited FLT3-positive AML cells THP-1 and MV-4-11 with IC50 around 10-30 nM. Also, FL-DM1 induced apoptosis and cell cycle arrest at G2/M phase in these cells detected by flow cytometry. In our previous studies, we generated FLT3-ITD transformed HCD-57 cells. HCD-57 cells are FLT3-negative erythroleukemia cells that depend on erythropoietin for survival. When infected with recombinant retroviruses carrying FLT3-ITD, they acquired ability to proliferate in the absence of EPO. We found that FL-DM1 inhibited HCD-57 cells transformed by FLT3-ITD, but not parental HCD-57 cells without FLT3 expression, indicating the selectivity of FL-DM1 to target FLT3-positive AML cells. In conclusion, our data demonstrated that FL-based drug conjugate can serve as an effective drug to target FLT3-expressing AML cells. Further studies will focus on in-vivo evaluation of FL-DM1 in animal models, the production of uncleavable SMCC linked FL-DM1 with improved in-vivo pharmacokinetic properties, and screening of FL muteins-DM1 conjugates with desired pharmacological properties. Disclosures No relevant conflicts of interest to declare.

scholarly journals Loss of ISWI ATPase SMARCA5 (SNF2H) in Acute Myeloid Leukemia Cells Inhibits Proliferation and Chromatid Cohesion

2020 ◽  
Vol 21 (6) ◽  
pp. 2073
Author(s):  
Tomas Zikmund ◽  
Helena Paszekova ◽  
Juraj Kokavec ◽  
Paul Kerbs ◽  
Shefali Thakur ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Cell Cycle Progression ◽  
Mitotic Division ◽  
Cycle Progression ◽  
Hematopoietic Stem ◽  
Chromatid Cohesion ◽  
Acute Myeloid Leukemia Cells ◽  
Acute Myeloid

ISWI chromatin remodeling ATPase SMARCA5 (SNF2H) is a well-known factor for its role in regulation of DNA access via nucleosome sliding and assembly. SMARCA5 transcriptionally inhibits the myeloid master regulator PU.1. Upregulation of SMARCA5 was previously observed in CD34+ hematopoietic progenitors of acute myeloid leukemia (AML) patients. Since high levels of SMARCA5 are necessary for intensive cell proliferation and cell cycle progression of developing hematopoietic stem and progenitor cells in mice, we reasoned that removal of SMARCA5 enzymatic activity could affect the cycling or undifferentiated state of leukemic progenitor-like clones. Indeed, we observed that CRISPR/cas9-mediated SMARCA5 knockout in AML cell lines (S5KO) inhibited the cell cycle progression. We also observed that the SMARCA5 deletion induced karyorrhexis and nuclear budding as well as increased the ploidy, indicating its role in mitotic division of AML cells. The cytogenetic analysis of S5KO cells revealed the premature chromatid separation. We conclude that deleting SMARCA5 in AML blocks leukemic proliferation and chromatid cohesion.

miR‐345‐5p regulates proliferation, cell cycle, and apoptosis of acute myeloid leukemia cells by targeting AKT2

2018 ◽  
Vol 120 (2) ◽  
pp. 1620-1629 ◽  
Author(s):  
Xiaoyang Ying ◽  
Wanggang Zhang ◽  
Meiyun Fang ◽  
Weijun Zhang ◽  
Chenchen Wang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Leukemia Cells ◽  
Acute Myeloid Leukemia Cells ◽  
Acute Myeloid

Stromal-Derived Factors Modulate Ex Vivo Drug Responses of Primary Acute Myeloid Leukemia Cells

2015 ◽  
Vol 15 ◽  
pp. S8-S9
Author(s):  
Riikka Karjalainen ◽  
Tea Pemovska ◽  
Muntasir M. Majumder ◽  
Bhagwan Yadav ◽  
David Tamborero ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Ex Vivo ◽  
Leukemia Cells ◽  
Drug Responses ◽  
Acute Myeloid Leukemia Cells ◽  
Acute Myeloid

Dentatin Induces Apoptosis and Cell Cycle Arrest of Acute Myeloid Leukemia Cells

2020 ◽  
Vol 19 (1) ◽  
pp. 52-57
Author(s):  
Li Wen ◽  
Yuli Liang ◽  
Jing Li ◽  
Meijie Quan ◽  
Yanxiao Li ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Acute Myeloid Leukemia ◽  
Cell Viability ◽  
Cell Apoptosis ◽  
Myeloid Leukemia ◽  
Cell Counting ◽  
Dependent Manner ◽  
Cycle Arrest ◽  
Acute Myeloid Leukemia Cells ◽  
Acute Myeloid

Acute myeloid leukemia remains a therapeutic challenge in the medical field and improvement in chemotherapeutics is needed. In this paper, MOLM-13 cells were treated with different concentrations (0, 10, 50, 100 µM) of dentatin and cell viability was detected using Cell Counting Kit-8. Cell cycle and cell apoptosis rates were evaluated by flow cytometry. The relevant proteins were assessed by Western blot. Consequently, the results show that dentatin inhibits the cell viability in a dose-dependent manner. In addition, dentatin arrests the cell cycle at G1 phase (P ‹ 0.01). Moreover, dentatin induces the cell apoptosis. Further study revealed that dentatin downregulates the phosphorylated STAT3 and CyclinD1 but upregulates the cleaved caspase-3. In summary, this study confirms that dentatin inhibits MOLM-13 cell viability, increases cell apoptosis, and retards cell cycle.

FLT3 Expression Is Increased by MEIS1 and Collaborates with NUP98-HOX Fusion Genes in the Induction of Acute Myeloid Leukemia.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2552-2552
Author(s):  
Lars Palmqvist ◽  
Nicolas Pineault ◽  
Bob Argiropoulos ◽  
Adrian Wan ◽  
Keith R. Humphries
Keyword(s):  
Acute Myeloid Leukemia ◽  
Cell Line ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Parental Cell ◽  
Fusion Genes ◽  
Flt3 Ligand ◽  
Flt3 Expression ◽  
Acute Myeloid

Abstract The TALE family member and HOX cofactor MEIS1 is important in leukemic transformation. MEIS1 has, although non-leukemogenic on its own, been shown to strongly collaborate with several HOX genes and NUP98-HOX fusions to induce acute myeloid leukemia (AML). We have recently described a novel in vitro culture system of cell lines established from murine primary bone marrow cells transduced with the AML-associated fusion gene NUP98-HOXD13 or an engineered NUP98-HOXA10 fusion. These pre-leukemic NUP98-HOX cell lines are transplantable and can efficiently be converted into AML-inducing cells upon MEIS1 transduction. Conveniently, the MEIS1 transduced cells can be purified and preserve their leukemogenic potential even after extensive in vitro expansion. Thus, the availability of the NUP98-HOX cell lines system provided the opportunity to investigate and characterize the mechanism of MEIS1-mediated AML-conversion. Potentially interesting target or candidate genes were screened for expression changes between the parental pre-leukemic lines and AML-inducing MEIS1 transduced cell lines with quantitative RT-PCR and Western blotting. Aberrant expression or mutations of the receptor tyrosine kinase FLT3 gene is a common finding in human AML. Interestingly, Flt3 was found induced 5 to 10 fold in MEIS1 transduced cell lines compared to the parental cell lines. The observed increase in Flt3 expression provided the MEIS1 transduced cells with Flt3 ligand driven growth. This was not seen in the parental cell lines, which could not proliferate with Flt3 ligand as single cytokine or with a MEIS1-homeodomain mutant expressing cell line. Importantly, the Flt3 inhibitor AG1295 could block the proliferative effect of the Flt3 ligand in the MEIS1 transduced cell lines. To test whether Flt3 could substitute for MEIS1-mediated induction of AML in NUP98-HOX pre-leukemic cells, a NUP98-HOXA10 cell line was transduced with an MSCV-Flt3-IRES-YFP construct. The resulting Flt3-transduced cells were shown to express Flt3 at levels similar to that of MEIS1 transduced cells without any significant increase in endogenous Meis1 expression. Transplantation of these cells into mice led to lethal and transplantable AML with a median disease onset of 116 days (n=8) compared to 59 days for MEIS1 (n=4), whereas control transplants remained healthy (n=2). In conclusion, this study demonstrates that MEIS1 can induce Flt3 expression and that Flt3 can collaborate with NUP98-HOX fusion genes in the induction of acute myeloid leukemia. Furthermore, theses results suggest a model in which the leukemogenic synergism of MEIS1 on HOX-mediated leukemia might in part be mediated through FLT3-dependent pathways.

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