Myeloid Leukemia Cell Line MV4-11 Research Articles

Development of 2-Aminoadenine-Based Proteolysis-Targeting Chimeras (PROTACs) as Novel Potent Degraders of Monopolar Spindle 1 and Aurora Kinases.

Monopolar spindle 1 (Mps1, also known as TTK) and Aurora kinase (AURK) A and B are critical regulators of mitosis and have been linked to the progression of various cancers. Here, we report the design, synthesis, and biological evaluation of a series of PROTACs (proteolysis-targeting chimeras) targeting TTK and AURKs. We synthesized various degrader molecules based on four different 2-aminoadenine-based ligands, recruiting either cereblon or VHL as the E3-ligase. Our research showed that the nature of the linker and modification of the ligand significantly influence the target specificity and degradation efficacy. Notably, compound 19, among the most potent degraders, demonstrated robust proteasome-mediated degradation of TTK with D max of 66.5% and DC50 value (6 h) of 17.7 nM as compared to its structurally akin inhibitor control, 23. The cytotoxicity of most of the synthesized chimeras against acute myeloid leukemia cell line MV4-11 was lower than that of the corresponding parent inhibitors. However, we could also identify degraders such as 15 and 26 that induce potent AURKA degradation and display comparable antiproliferative activities to their parent compound SF1. Compound 15 degrades AURKA with low DC50 value of 2.05 nM, which is 77-fold and 21-fold more selective toward AURKB and TTK and has an EC50 value of 39 nM against cancer MV4-11 cells. Overall, the observations we made with the degrader molecules we developed can further aid in the design and development of optimized TTK or AURK degraders for cancer therapy.

Cytotoxic Indolocarbazoles From a Marine-Derived Streptomyces Sp. OUCMDZ-5380

Under the guidance of global natural product social molecular networking, three new indolocarbazoles named streptocarbazoles F–H (1-3), along with staurosporine (4) were isolated from the marine-derived Streptomyces sp. OUCMDZ-5380. Structures of streptocarbazoles F–H were, respectively, determined as N-demethyl-N-hexanoylstaurosporine (1), N-demethyl-N-(2-methyl-3-methoxypyridin-4-yl) staurosporine staurosporine (2), and 4-(N-demethylstaurosporine-N-yl)-1,2-dimethyl-3-methoxypyridinium (3) by spectroscopic analysis and electronic circular dichroism comparison with staurosporine. Compared with staurosporine (4), streptocarbazoles F–H (1-3) showed a selective antiproliferation of the acute myeloid leukemia cell line MV4-11 with the IC50 values of 0.81, 0.55, and 1.88 μM, respectively.

Synthesis and bioactivity studies of covalent inhibitors derived from (-)-Chaetominine

We reported herein the synthesis and bioactivity studies of compounds derived from the natural product (-)-Chaetominine (6). The key feature of these compounds is the incorporation of electrophilic groups that are capable of forming covalent bonds with the cysteine or threonine residues of cellular proteins. The cell growth inhibition activities of these derivatives of 6 were tested in four cancer cell lines, i.e. a leukemia cell line K562, a multiple myeloma cell line MM1.S, an acute myeloid leukemia cell line MV4-11, and a colon cancer cell line RKO. The data show that cellular growth inhibition IC50 values of 29, an acrylamide-containing molecule, are 9-17 folds more potent than that of 6, while other acrylamide-containing compounds are much less potent, suggesting 29 might have covalent interactions with cellular target proteins. Collectively, incorporation of an acrylamide moiety into 6 is a good strategy to improve its cell growth inhibition activity in cancer cell lines.

Discovery of novel small molecule induced selective degradation of the bromodomain and extra-terminal (BET) bromodomain protein BRD4 and BRD2 with cellular potencies

The BET proteins BRD2, BRD3, and BRD4 play important roles in transcriptional regulation and can be degraded by proteolysis-targeting chimeras (PROTACs) for BET proteins. However, the lack of intra-BET proteins selectivity limits the scope of current degraders as probes for target validation and could lead to unwanted side effects or toxicity in a therapeutic setting. We describe herein the design, synthesis, and evaluation of PROTAC BET degraders, based on the BET inhibitor with selectivity for the first Bromodomain benzo[cd]indole-2-one, alkylamide linker and cereblon ligand thalidomide. Compound 15 potently and rapidly induces reversible, long-lasting, and unexpectedly selective removal of BRD4 and BRD2 over BRD3, which not only effectively inhibits cell growth in human acute leukemia cell lines, but also very effective in inhibiting solid tumors with low cytotoxic effect in the cell profiles of NCI 60 cell lines. Remarkable dependency on linker length was observed for BRD4-degrading and c-Myc-driven antiproliferative activities in acute myeloid leukemia cell line MV4-11. The small-molecular 15 represents a novel, potent, and selective class of BRD4 and BRD2 degraders for the development of therapeutics to treat cancers.

Effect of Low-Dose Triptolide and Sorafenib Alone and Their Combination on AML Cell Line MV411 and the Pathway of STAT5

To investigate the effects of inhibiting proliferation and inducing apoptosis of low-dose triptolide and sorafenib alone or in combination on FLT3-ITD+ acute myeloid leukemia cell line MV4-11 and STAT5 pathway. The MV4-11 cells were treated with low dose triptolide(IC20) and sorafenib(IC50) alone or in combination for 48 hours. The cell proliferation and inhibition were detected by using CCK-8 kit, the cell apoptosis was detected by flow cytometry, the expression of FLT3,STAT5 in mRNA and protein levels was detected by RT-PCR and Western blot respectively. The treatment of MV4-11 cells with low dose triptolide and sorafenib alone and in combination for 48 hours could inhibit cell proliferation and induce cell apoptosis, moreover the inhibitory rate and apoptotic rate of MV4-11 cells in drug-combination group both were higher than those in single drug group. The mRNA expression and protein expression of FLT3,STAT5 signaling pathway in drug combination group were significantly lower than those in single drug group. Low-dose triptolide combined with sorafenib can synergistically inhibit the proliferation and induce the apoptosis of MV4-11 cells, which may be related with the inhibition of FLT3 and STAT5 pathway.

Identification of pyrrolo[2,3-d]pyrimidines as potent HCK and FLT3-ITD dual inhibitors

A series of novel pyrrolo[2,3-d]pyrimidines were synthesized by introducing 15 different amino acids to 7-cyclohexyl-5-(4-phenoxyphenyl)-7H-pyrrolo[2,3-d]pyrimidine-4-amine. Compounds with potent activities against HCK and FLT3-ITD were evaluated in viability studies with acute myeloid leukemia cell line MV4-11. Our structure activity relationship analyses lead to the identification of compound 31, which exhibited potent HCK and FLT3-ITD inhibition and activity against the MV4-11 cell line.

Development of a potent and selective FLT3 kinase inhibitor by systematic expansion of a non-selective fragment-screening hit

A non-selective inhibitor (1) of FMS-like tyrosine kinase-3 (FLT3) was identified by fragment screening and systematically modified to afford a potent and selective inhibitor 26. We confirmed that 26 inhibited the growth of FLT-3-activated human acute myeloid leukemia cell line MV4-11. Our design strategy enabled rapid development of a novel type of FLT3 inhibitor from the hit fragment in the absence of target-structural information.

Steroids from the aerial parts of Leonurus japonicus

Two new steroids, (24S)-stigmast-4,28-diene-24-ol-3-one (1) and mono-β-sitosteryl azelate (2), along with ten known analogues (3–12), were isolated from the ethanolic extract of Leonurus japonicus Houtt. Their structures were elucidated by spectroscopic and chemical methods. The absolute configuration of 1 was confirmed by single crystal X-ray crystallographic analysis using anomalous scattering of Cu Kα radiation. Compounds 3, 4, and 9 showed significant inhibitory activities against ADP-induced platelet aggregation, while compound 1 had a weak cytotoxic activity against acute myeloid leukemia cell line MV4-11.

Phenolic Glucosides from Dendrobium aurantiacum var. denneanum and Their Bioactivities

A new 8,4'-oxyneolignane glucoside 1 has been isolated from the stems of Dendrobium aurantiacum var. denneanum together with six known phenolic glucosides 2−7. The structure of the new compound, including its absolute configuration, was determined by spectroscopic and chemical methods as (−)-(7S,8R,7'E)-4-hydroxy-3,3',5,5'-tetramethoxy-8,4'-oxyneolign-7'-ene-7,9,9'-triol 7,9'-bis-O-β-D-glucopyranoside (1). In the in vitro assays, compound 1 and (−)-syringaresinol-4,4'-bis-O-β-D-glucopyranoside (2) showed evident activity against glutamate-induced neurotoxicity in PC12 cells. Shashenoside I (4) showed a selective cytotoxic activity with the IC50 value of 4.17 μM against the acute myeloid leukemia cell line MV4-11, while it was inactive against 10 other human tumor cell lines.

A Novel Class of Small Molecule Inhibitors of HDAC6

Histone deacetylases (HDACs) are a family of enzymes that play significant roles in numerous biological processes and diseases. HDACs are best known for their repressive influence on gene transcription through histone deacetylation. Mapping of nonhistone acetylated proteins and acetylation-modifying enzymes involved in various cellular pathways has shown protein acetylation/deacetylation also plays key roles in a variety of cellular processes including RNA splicing, nuclear transport, and cytoskeletal remodeling. Studies of HDACs have accelerated due to the availability of small molecule HDAC inhibitors, most of which contain a canonical hydroxamic acid or benzamide that chelates the metal catalytic site. To increase the pool of unique and novel HDAC inhibitor pharmacophores, a pharmacological active compound screen was performed. Several unique HDAC inhibitor pharmacophores were identified in vitro. One class of novel HDAC inhibitors, with a central naphthoquinone structure, displayed a selective inhibition profile against HDAC6. Here we present the results of a unique class of HDAC6 inhibitors identified using this compound library screen. In addition, we demonstrated that treatment of human acute myeloid leukemia cell line MV4-11 with the selective HDAC6 inhibitors decreases levels of mutant FLT-3 and constitutively active STAT5 and attenuates Erk phosphorylation, all of which are associated with the inhibitor's selective toxicity against leukemia.

Plasma Membrane Nucleolin Is a Receptor for the Anticancer Aptamer AS1411 in MV4-11 Leukemia Cells

AS1411 is a DNA aptamer that is in phase II clinical trials for relapsed or refractory acute myeloid leukemia and for renal cell carcinoma. AS1411 binds to nucleolin, a protein that is overexpressed in the cytoplasm and on the plasma membrane of some tumor cells compared with normal cells. Studies were performed to determine whether cell surface nucleolin is a receptor for AS1411 in the acute myeloid leukemia cell line MV4-11. Biotinylation of MV4-11 cell surface proteins followed by immunoblotting of the biotinylated proteins showed that full-length (106 kDa) and truncated forms of nucleolin were present on the cell surface. In contrast, K-562 cells, which are 4-fold less sensitive than MV4-11 cells to AS1411, showed no full-length nucleolin and lesser amounts of the truncated forms of nucleolin on the cell surface. Incubation of MV4-11 cells with [(32)P]AS1411 and immunoprecipitation of the plasma membrane fraction with anti-nucleolin antibody demonstrated the presence of [(32)P]AS1411-nucleolin complexes. Anti-nucleolin antibody inhibited binding of fluorescein isothiocyanate (FITC)-AS1411 to plasma membrane nucleolin 56 +/- 10% SE (P < 0.01) compared with cells incubated with FITC-AS1411 only. Cellular uptake of [(32)P]AS1411 into MV4-11 cells was blocked by a 20-fold excess of unlabeled AS1411 but not by a 20-fold excess of the biologically inactive oligonucleotide CRO-26. Uptake was approximately 3-fold faster into MV4-11 cells than into K-562 cells. Partial knockdown of plasma membrane and cytosolic nucleolin in MCF-7 cells resulted in a 3-fold decrease in AS1411 uptake. These results provide evidence that plasma membrane nucleolin is a functional receptor for AS1411 in MV4-11 cells.

Preclinical characterization of Aurora kinase inhibitor R763/AS703569 identified through an image-based phenotypic screen

Aurora kinases play a key role in mitotic progression. Over-expression of Aurora kinases is found in several human cancers and correlated with histological malignancy and clinical outcomes. Therefore, Aurora kinase inhibitors should be useful in the treatment of cancers. Cell-based screening methods have an advantage over biochemical approaches because hits can be optimized to inhibit targets in the proper intracellular context. We developed a novel Aurora kinase inhibitor R763/AS703569 using an image-based phenotypic screen. The anti-proliferative effect was examined in a panel of tumor cell lines and primary cells. The efficacy was determined in a broad panel of xenograft models. R763/AS703569 inhibits Aurora kinases, along with a limited number of other kinases including FMS-related tyrosine kinase 3 (FLT3), and has potent anti-proliferative activity against many cell types accompanying unique phenotypic changes such as enlarged cell size, endoreduplication and apoptosis. The endoreduplication cycle induced by R763/AS703569 was irreversible even after the compound was withdrawn from the culture. Oral administration of R763/AS703569 demonstrated marked inhibition of tumor growth in xenograft models of pancreatic, breast, colon, ovarian, and lung tumors and leukemia. An acute myeloid leukemia cell line MV4-11, which carries a FLT3 internal tandem duplication mutation, is particularly sensitive to R763/AS703569 in vivo. R763/AS703569 is a potent inhibitor of Aurora kinases and exhibited significant anti-proliferative activity against a wide range of tumor cells both in vitro and in vivo. Inhibition of Aurora kinases has the potential to be a new addition to the treatment of cancers.