Human Leukemia K562 Cells Research Articles

Functional characterization of native Piezo1 as calcium and magnesium influx pathway in human myeloid leukemia cells.

Piezo1 is a Ca2+-permeable mechanically activated ion channel that is involved in various physiological processes and cellular responses to mechanical stimuli. The study of biophysical characteristics of Piezo1 is important for understanding the mechanisms of its function and regulation. Stretch activation, a routine approach that is applied to stimulate Piezo1 activity in the plasma membrane, has a number of significant limitations that complicate precise single-channel analysis. Here, we aimed to determine pore properties of native Piezo1, specifically to examine permeation for physiologically relevant signaling divalent ions (calcium and magnesium) in human myeloid leukemia K562 cells using Piezo1-specific chemical agonist, Yoda1. Using a combination of low-noise single-current patch-clamp recordings of Piezo1 activity in response to Yoda1, we have determined single-channel characteristics of native Piezo1 under various ionic conditions. Whole-cell assay allowed us to directly measure Piezo1 single currents carried by Ca2+ or Mg2+ ions in the absence of other permeable cations in the extracellular solutions; unitary conductance values estimated at various concentrations of Mg2+ revealed strong saturation effect. Patch clamp data complemented with fluorescent imaging clearly evidenced Ca2+ and Mg2+ entry via native Piezo1 channel in human leukemia K562 cells. Mg2+ influx via Piezo1 was detected under quasi-physiological conditions, thus showing that Piezo1 channels could potentially provide the physiological relevant pathway for Mg2+ ion transport and contribute to the regulation of Mg2+-dependent intracellular signaling.

Novel centratherin derivatives: Molecular docking design, asymmetric synthesis, and antitumoral activity

Centratherin is a sesquiterpene lactone that has the potential to inhibit target proteins for cancer therapy, such as the inflammatory mediator NF-κB. Indoles also exhibit antitumoral activity and can modulate the NF-κB signaling pathway. Here we describe a molecular-docking guided semi-synthesis of indole-containing centratherin derivatives. In silico studies indicated that these compounds have high affinity to NF-κB and do not present toxicity or carcinogenicity. Two enantiomeric series of indole-centratherin hybrids were synthesized in three steps with good yields and ee, employing an organocatalyzed Friedel-Crafts alkylation as a key step. The compounds were evaluated against human leukemia K562 cells and showed promising antitumoral activities with IC50 ranging from 0.49 to 7.83 μM.

Exploring the Composition and Bioactivity of Hedychium flavum Leaf and Stem Essential Oil: In Vitro Assessment of Antibacterial, Antioxidant, Cytotoxicity, and Enzyme Inhibitory Activities

Hedychium flavum is an edible, medicinal, and aromatic plant widely cultivated for its essential oil. So far, little studies have been done on its phytoconstituents and bioactivities. Hence, the research aimed to determine the chemical constituents of leaf essential oil (L-EO) and stem essential oil (S-EO) of H. flavum and first estimate their antibacterial, antioxidant, cytotoxic, and enzyme inhibitory activities. According to gas chromatography-flame ionization detector/mass spectrometer (GC-FID/MS) assay, L-EO was mainly composed of β-pinene (33.4%), α-pinene (10.4%), humulene (6.8%), β-caryophyllene (6.0%), eucalyptol (6.0%), caryophyllene oxide (5.5%), endo-borneol (3.8%), humulene epoxide II (3.7%), and D-limonene (3.2%). The predominant components of S-EO were β-pinene (17.2%), eucalyptol (9.7%), nerolidol (7.8%), α-phellandrene (6.7%), α-pinene (5.8%), β-caryophyllene (5.4%), terpinen-4-ol (4.5%), D-limonene (4.4%), p-cymene (3.7%), endo-borneol (3.5%), and α-terpineol (3.5%). For the bioactivities, L-EO and S-EO showed strong antibacterial activity against Escherichia coli, Enterococcus faecalis, and Bacillus subtilis with the minimum inhibitory concentration (MIC) of 9.77–625.00 µg/mL and the minimum bactericidal concentration (MBC) of 9.77–1250.00 µg/mL. Both L-EO and S-EO exhibited moderate antioxidant activity in the DPPH (14.52 ± 0.93 mg/mL and 4.73 ± 0.15 mg/mL, respectively) and ABTS (4.05 ± 0.75 mg/mL and 2.38 ± 0.14 mg/mL, respectively) free radical scavenging capacity. S-EO showed selective cytotoxicity on human leukemic K562 cell line (IC50 = 93.94 ± 0.91 µg/mL), which was nearly three times that of noncancer L929 cell line (IC50 = 294.49 ± 9.40 µg/mL). In enzyme inhibitory properties, L-EO exerted a potent inhibition on α-glucosidase (IC50 = 1.03 ± 0.02 mg/mL), and both essential oils had weak inhibition against cholinesterase and tyrosinase. Thus, H. flavum L-EO and S-EO possess antibacterial, antioxidant, cytotoxic, and enzyme inhibitory activities with potential for exploitation in the food, cosmetic, and pharmaceutical industries.

A Carbon 21 Steroidal Glycoside with Pregnane Skeleton from Cynanchum atratum Bunge Promotes Megakaryocytic and Erythroid Differentiation in Erythroleukemia HEL Cells through Regulating Platelet-Derived Growth Factor Receptor Beta and JAK2/STAT3 Pathway.

Erythroleukemia is a rare form of acute myeloid leukemia (AML). Its molecular pathogenesis remains vague, and this disease has no specific therapeutic treatments. Previously, our group isolated a series of Carbon 21 (C-21) steroidal glycosides with pregnane skeleton from the root of Cynanchum atratum Bunge. Among them, we found that a compound, named BW18, can induce S-phase cell cycle arrest and apoptosis via the mitogen-activated protein kinase (MAPK) pathway in human chronic myeloid leukemia K562 cells. However, its anti-tumor activity against erythroleukemia remains largely unknown. In this study, we aimed to investigate the anti-erythroleukemia activity of BW18 and the underlying molecular mechanisms. Our results demonstrated that BW18 exhibited a good anti-erythroleukemia activity in the human erythroleukemia cell line HEL and an in vivo xenograft mouse model. In addition, BW18 induced cell cycle arrest at the G2/M phase and promoted megakaryocytic and erythroid differentiation in HEL cells. Furthermore, RNA sequencing (RNA-seq) and rescue assay demonstrated that overexpression of platelet-derived growth factor receptor beta (PDGFRB) reversed BW18-induced megakaryocytic differentiation in HEL cells, but not erythroid differentiation. In addition, the network pharmacology analysis, the molecular docking and cellular thermal shift assay (CETSA) revealed that BW18 could inactivate Janus tyrosine kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway, which might mediate BW18-induced erythroid differentiation. Taken together, our findings elucidated a novel role of PDGFRB in regulating erythroleukemia differentiation and highlighted BW18 as an attractive lead compound for erythroleukemia treatment.

Circumvention of Topoisomerase IIα Intron 19 Intronic Polyadenylation in Acquired Etoposide-Resistant Human Leukemia K562 Cells.

DNA topoisomerase IIα (TOP2α; 170 kDa, TOP2α/170) is an essential enzyme for proper chromosome dysjunction by producing transient DNA double-stranded breaks and is an important target for DNA damage-stabilizing anticancer agents, such as etoposide. Therapeutic effects of TOP2α poisons can be limited due to acquired drug resistance. We previously demonstrated decreased TOP2α/170 levels in an etoposide-resistant human leukemia K562 subline, designated K/VP.5, accompanied by increased expression of a C-terminal truncated TOP2α isoform (90 kDa; TOP2α/90), which heterodimerized with TOP2α/170 and was a determinant of resistance by exhibiting dominant-negative effects against etoposide activity. Based on 3'-rapid amplification of cDNA ends, we confirmed TOP2α/90 as the translation product of a TOP2α mRNA in which a cryptic polyadenylation site (PAS) harbored in intron 19 (I19) was used. In this report, we investigated whether the resultant intronic polyadenylation (IPA) would be attenuated by blocking or mutating the I19 PAS, thereby circumventing acquired drug resistance. An antisense morpholino oligonucleotide was used to hybridize/block the PAS in TOP2α pre-mRNA in K/VP.5 cells, resulting in decreased TOP2α/90 mRNA/protein levels in K/VP.5 cells and partially circumventing drug resistance. Subsequently, CRISPR/CRISPR-associated protein 9 with homology-directed repair was used to mutate the cryptic I19 PAS (AATAAA→ACCCAA) to prevent IPA. Gene-edited clones exhibited increased TOP2α/170 and decreased TOP2α/90 mRNA/protein and demonstrated restored sensitivity to etoposide and other TOP2α-targeted drugs. Together, results indicated that blocking/mutating a cryptic I19 PAS in K/VP.5 cells reduced IPA and restored sensitivity to TOP2α-targeting drugs. SIGNIFICANCE STATEMENT: The results presented in this study indicate that CRISPR/CRISPR-associated protein 9 gene editing of a cryptic polyadenylation site (PAS) within I19 of the TOP2α gene results in the reversal of acquired resistance to etoposide and other TOP2-targeted drugs. An antisense morpholino oligonucleotide targeting the PAS also partially circumvented resistance.

Variable characteristics overlooked in human K-562 leukemia cell lines with a common signature

K-562 is a well-known in vitro cellular model that represents human leukemia cell lines. Although the K-562 cells have been extensively characterized, there are inconsistencies in the data across publications, showing the presence of multiple K-562 cell lines. This suggests that analyzing a single K-562 cell line is insufficient to provide reliable reference data. In this study, we compared three K-562 cell lines with different IDs (RCB0027, RCB1635, and RCB1897) to investigate the fundamental characteristics of K-562 cells. Amplifications of the BCR-ABL1 fusion gene and at 13q31 were detected in all three cell lines, whereas each genome exhibited distinctive features of sequence variants and loss of heterozygosity. This implies that each K-562 cell line can be characterized by common and unique features through a comparison of multiple K-562 cell lines. Variations in transcriptome profiles and hemoglobin synthesis were also observed among the three cell lines, indicating that they should be considered sublines that have diverged from the common ancestral K-562 despite no changes from the original cell name. This leads to unintentional differences in genotypes and/or phenotypes among cell lines that share the same name. These data show that characterizing a single K-562 cell line does not necessarily provide data that are applicable to other K-562 cells. In this context, it is essential to modify cell names in accordance with changes in characteristics during cell culture. Furthermore, our data could serve as a reference for evaluating other K-562 sublines, facilitating the discovery of new K-562 sublines with distinct characteristics. This approach results in the accumulation of K-562 sublines with diverged characteristics and expands the options available, which may help in selecting the most suitable K-562 subline for each experiment.

Ethanolic extract of Euphorbia Gypsicola induces differentiation and apoptosis in human myeloid leukemia K562 cells

IntroductionThe Euphorbiaceae family, widely distributed and long utilized in traditional medicine, has been recognized for its potential in developing anti-cancer drugs. The current study investigates the capacity of Euphorbia gypsicola extract to induce apoptosis and differentiation in the human myeloid leukemia K562 cell line. MethodsCell viability was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptotic activity was visually evaluated through acridine orange/ethidium bromide (AO/EB) dye staining and annexin V/PI double labeling procedures. Induction of differentiation was examined using nitro blue tetrazolium (NBT) reduction and Wright-Giemsa staining assays. The expression of apoptosis-related proteins including Bax, Bcl2 and Survivin was evaluated by western blotting method. ResultsThe E. gypsicola extract exhibited potent medication properties with IC50 values of 207.59, 48.58, and 7.08 ng/mL at 24, 48, and 72 h, respectively. Fluorescence microscopy, DNA fragmentation, annexin V/PI double staining, and sub-G1 cell cycle arrest confirmed apoptosis occurrence in K562 cells treated with the E. gypsicola extract. Our findings demonstrated that differentiated cells reduced NBT yellow solution after endocytosis, forming dark crystals. Wright Giemsa staining observations indicated a decrease in nuclear volume-to-cytoplasm ratio in K562 cells treated with the crude extract, signifying Induction of differentiation. Furthermore, western blot analysis revealed down-regulation of Survivin protein expression and up-regulation of Bax protein level following treatment with the E. gypsicola extract. However, no significant decrease in Bcl2 protein expression level was observed in K562 cells. ConclusionThese findings indicate the growth inhibitory effects of the E. gypsicola extract on leukemia K562 cells, which supports the further study of this plant to discover novel therapeutic compounds for the treatment of leukemia.

Evaluation of multidrug resistance in tumors using 99mTc-doxorubicin

Doxorubicin (DOX) is a potent chemotherapeutic agent used as the first-choice drug in treating different types of cancer, such as leukemia, lymphoma, and breast cancer, among others. However, the development of multidrug resistance represents a significant obstacle to the successful treatment of tumors. In this study, we assessed whether labeled DOX could be uptaken by susceptible and multidrug-resistant cell lines and by tumors in vivo in animals. The efficiency of DOX labeling was maintained at around 90% in this work. To evaluate the effect of 99mTc-DOX on cells expressing active P-glycoprotein (Pgp), we utilized cultured human chronic myeloid leukemia K562 cells and the resistant counterpart Lucena 1 cells. Lucena 1 cell line showed overexpression of Pgp that was not observed in K562. Our results suggested that the resistance to labeled or unlabeled DOX can be reversed by Pgp inhibition and can be easily detected. In conclusion, administering 99mTc-DOX into mice enables the differentiation between multidrug-resistant tumors in a non-invasive way and the evaluation of tumor resistance and possible chemosensitizers.

Use of CRISPR/Cas9 with Homology-Directed Repair to Gene-Edit Topoisomerase IIβ in Human Leukemia K562 Cells: Generation of a Resistance Phenotype.

DNA topoisomerase IIβ (TOP2β/180; 180 kDa) is a nuclear enzyme that regulates DNA topology by generation of short-lived DNA double-strand breaks, primarily during transcription. TOP2β/180 can be a target for DNA damage-stabilizing anticancer drugs, whose efficacy is often limited by chemoresistance. Our laboratory previously demonstrated reduced levels of TOP2β/180 (and the paralog TOP2α/170) in an acquired etoposide-resistant human leukemia (K562) clonal cell line, K/VP.5, in part due to overexpression of microRNA-9-3p/5p impacting post-transcriptional events. To evaluate the effect on drug sensitivity upon reduction/elimination of TOP2β/180, a premature stop codon was generated at the TOP2β/180 gene exon 19/intron 19 boundary (AGAA//GTAA→ATAG//GTAA) in parental K562 cells (which contain four TOP2β/180 alleles) by CRISPR/Cas9 editing with homology-directed repair to disrupt production of full-length TOP2β/180. Gene-edited clones were identified and verified by quantitative polymerase chain reaction and Sanger sequencing, respectively. Characterization of TOP2β/180 gene-edited clones, with one or all four TOP2β/180 alleles mutated, revealed partial or complete loss of TOP2β mRNA/protein, respectively. The loss of TOP2β/180 protein correlated with decreased (2-{4-[(7-chloro-2-quinoxalinyl)oxy]phenoxy}propionic acid)-induced DNA damage and partial resistance in growth inhibition assays. Partial resistance to mitoxantrone was also noted in the gene-edited clone with all four TOP2β/180 alleles modified. No cross-resistance to etoposide or mAMSA was noted in the gene-edited clones. Results demonstrated the role of TOP2β/180 in drug sensitivity/resistance in K562 cells and revealed differential paralog activity of TOP2-targeted agents. SIGNIFICANCE STATEMENT: Data indicated that CRISPR/Cas9 editing of the exon 19/intron 19 boundary in the TOP2β/180 gene to introduce a premature stop codon resulted in partial to complete disruption of TOP2β/180 expression in human leukemia (K562) cells depending on the number of edited alleles. Edited clones were partially resistant to mitoxantrone and XK469, while lacking resistance to etoposide and mAMSA. Results demonstrated the import of TOP2β/180 in drug sensitivity/resistance in K562 cells and revealed differential paralog activity of TOP2-targeted agents.

Antiproliferative and Apoptosis-Inducing Effects of Ethanolic Extract of Morus Alba Leaves on Human Chronic Myeloid Leukaemia K-562 Cell Lines

The rate of occurrence and prevalence of chronic myeloid leukaemia (CML) are increasing globally, despite it being a rare type of cancer. Morus alba also known as mulberry, has been used in Chinese traditional medicine for a long time to treat various conditions and diseases like hypertension and arthritis. Modern scientific studies have also recognized its medicinal properties, including antioxidant, antidiuretic, antidiabetic, antimicrobial and anticancer. However, its antiproliferative effects on specifically human CML K-562 cell lines remain poorly elucidated. This study aims to determine the antiproliferative effects of M. alba on K-562 cells. In vitro cytotoxicity was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Acridine orange and propidium iodide (AO/PI) dual staining were then employed to assess the method of cell death. The ethanolic extract of M. alba leaves exhibited significant antiproliferative activity, with the lowest maximal half inhibitory concentration (IC50) value observed at 72 hours being 23 µg/mL. Notably, AO/PI staining revealed significant morphological changes, such as membrane blebbing, nuclear fragmentation, and indicator of early apoptosis, and late apoptosis. These results demonstrated that ethanolic extract of M. alba leaves induces apoptotic cell death in K-562 cells. Overall, these findings suggested that ethanolic extract of M. alba leaves exerts potent antiproliferative effects on human CML K-562 cells a in time- and dose-dependent manner.

Integration of transcription regulation and functional genomic data reveals lncRNA SNHG6’s role in hematopoietic differentiation and leukemia

BackgroundLong non-coding RNAs (lncRNAs) are pivotal players in cellular processes, and their unique cell-type specific expression patterns render them attractive biomarkers and therapeutic targets. Yet, the functional roles of most lncRNAs remain enigmatic. To address the need to identify new druggable lncRNAs, we developed a comprehensive approach integrating transcription factor binding data with other genetic features to generate a machine learning model, which we have called INFLAMeR (Identifying Novel Functional LncRNAs with Advanced Machine Learning Resources).MethodsINFLAMeR was trained on high-throughput CRISPR interference (CRISPRi) screens across seven cell lines, and the algorithm was based on 71 genetic features. To validate the predictions, we selected candidate lncRNAs in the human K562 leukemia cell line and determined the impact of their knockdown (KD) on cell proliferation and chemotherapeutic drug response. We further performed transcriptomic analysis for candidate genes. Based on these findings, we assessed the lncRNA small nucleolar RNA host gene 6 (SNHG6) for its role in myeloid differentiation. Finally, we established a mouse K562 leukemia xenograft model to determine whether SNHG6 KD attenuates tumor growth in vivo.ResultsThe INFLAMeR model successfully reconstituted CRISPRi screening data and predicted functional lncRNAs that were previously overlooked. Intensive cell-based and transcriptomic validation of nearly fifty genes in K562 revealed cell type-specific functionality for 85% of the predicted lncRNAs. In this respect, our cell-based and transcriptomic analyses predicted a role for SNHG6 in hematopoiesis and leukemia. Consistent with its predicted role in hematopoietic differentiation, SNHG6 transcription is regulated by hematopoiesis-associated transcription factors. SNHG6 KD reduced the proliferation of leukemia cells and sensitized them to differentiation. Treatment of K562 leukemic cells with hemin and PMA, respectively, demonstrated that SNHG6 inhibits red blood cell differentiation but strongly promotes megakaryocyte differentiation. Using a xenograft mouse model, we demonstrate that SNHG6 KD attenuated tumor growth in vivo.ConclusionsOur approach not only improved the identification and characterization of functional lncRNAs through genomic approaches in a cell type-specific manner, but also identified new lncRNAs with roles in hematopoiesis and leukemia. Such approaches can be readily applied to identify novel targets for precision medicine.

Eugenol's Molecular Warfare against Human Leukemia K562 cells: In Vitro Insights to Chemotherapeutic Potentials

Background: The search for effective anticancer agents has led to an increased focus on natural compounds, given their role as the foundation for many chemotherapeutic drugs. Eugenol (EUG) and Bis-Eugenol (Bis-EUG), derived from clove oil, have shown promise due to their antioxidative, anti-inflammatory, pro-apoptotic, and anti-proliferative properties across various cancer cell lines. This study aims to elucidate the chemotherapeutic potential of EUG and Bis-EUG on human leukemia K562 cells, exploring their ability to modulate apoptosis and cell proliferation. Objective: To assess the in vitro anticancer effects of EUG and Bis-EUG on K562 cell lines through various assays measuring cell viability, apoptosis, gene expression, and nitric oxide release, with a focus on elucidating the mechanisms underlying their anticancer activity. Methods: The study employed an inter-collaborative approach, utilizing MTT assays to determine the IC50 values of EUG and Bis-EUG on K562 cells. Gene expression analysis of pro-apoptotic genes Caspase-3 and Caspase-9 was performed using RT-qPCR. Apoptotic changes were further analyzed through flow cytometry and Hoechst 33258 staining to observe morphological alterations in treated cells. The release of nitric oxide (NO) as an indicator of anti-proliferative activity was measured using a Griess assay. Statistical analysis was conducted using GraphPad Prism Software, Version 9, and Microsoft Excel, with a significance threshold of p ≤ 0.05. Results: The IC50 values for EUG and Bis-EUG were determined to be 16.7 µM and 0.14 mM, respectively. Gene expression profiling revealed a significant increase in Caspase-3 and Caspase-9 expression, indicating the activation of apoptotic pathways. Flow cytometry and Hoechst 33258 staining confirmed the induction of apoptosis, with noticeable changes in cell morphology and nuclear fragmentation. The NO release assay demonstrated a dose-dependent increase in NO levels, highlighting the compounds' anti-proliferative effects. Conclusion: EUG and Bis-EUG exhibit potent anticancer effects on leukemia K562 cells by inducing apoptosis and inhibiting cell proliferation. The significant increase in NO levels and the activation of caspases suggest that these compounds may serve as effective chemotherapeutic agents. Further in vivo studies are warranted to explore their potential in cancer treatment regimens.

An Active Compound from the Pyrazine Family Induces Apoptosis by Targeting the Bax/Bcl2 and Survivin Expression in Chronic Myeloid Leukemia K562 Cells.

It has been established that pyrazine derivatives, which have widespread bioactivities, can effectively treat cancer. In this study, we investigated the effects of 2-methoxy-5-(oxiran-2-ylmethyl) phenyl pyrazine-2- carboxylate (2-mOPP), a new pyrazine derivative, on proliferation, viability, and apoptosis induction in human leukemia K562 cells. For this purpose, the K562 cells were treated with various concentrations (20-120 μM) of the 2-mOPP for 24-72 hours. Cell viability was determined by MTT growth inhibition assay. Apoptotic activity of 2-mOPP was investigated morphologically by Hoechst staining, cell surface expression assay of phosphatidylserine by Annexin-V/PI technique, as well as DNA fragmentation assay. The effect of 2-mOPP on the K562 cell cycle was studied by flow cytometry. To determine the impact of 2-mOPP on the expression of intrinsic apoptosis-related genes, Bcl2 (anti-apoptotic), Bax (pro-apoptotic), and Survivin genes expression levels were evaluated before and after treatment with 2-mOPP through Real-Time PCR analysis. The results revealed that 2-mOPP inhibited viability with IC50 of 25μM in 72 h. Morphological changes assessment by fluorescence microscopy, Annexin V/PI double staining by flow cytometry, and DNA ladders formation upon cell treatment with the 2-mOPP showed that this compound induces apoptosis at IC50 value. Cell cycle arrest was observed in the G0/G1 phase, and the sub-G1 cell population (the sign of apoptosis) increased in a time-dependent manner. Low expression levels of Bcl2 and Survivin in K562 cells were observed 24-72 h after treatment. Along with the down-regulation of Survivin and Bcl2, the expression of Bax was increased after treatment with 2-mOPP. These findings demonstrate that the new pyrazine derivative plays a crucial role in blocking the proliferation of the leukemic cells by inducing cell cycle arrest and apoptosis.

Bioassay-guided isolation of anti-leukemic steroids from Aglaia abbreviata by inducing apoptosis

The strategy of bioactivity-guided isolation is widely used to obtain active compounds as quickly as possible. Thus, the inhibitory effects on human erythroleukemia cells (HEL) were applied to guide the isolation of the anti-leukemic compounds from Aglaia abbreviata. As a result, 19 compounds (16 steroids, two phenol derivatives, and a rare C12 chain nor-sesquiterpenoid), including 13 new compounds, were isolated and identified based on spectroscopic data analysis, single-crystal X-ray diffraction data, and electronic circular dichroism (ECD) calculations. Among them, 9 steroids exhibited good selective anti-leukemic activity against HEL and K562 (human chronic myeloid leukemia cells) cells with IC50 values between 2.29 ± 0.18 μM and 19.58 ± 0.13 μM. Notably, all the active compounds had relatively lower toxicity on the normal human liver cell line (HL-7702). Furthermore, five compounds (1, 4, 8, 10, and 19) displayed good anti-inflammatory effects, with IC50 values between 7.15 ± 0.16 and 27.1 ± 0.37 μM. An α,β-unsaturated ketone or a 5,6Δ double bond was crucial for improving anti-leukemic effect from the structure–activity relationship analysis. The compound with the most potential, 14 was selected for the preliminary mechanistic study. Compound 14 can induce apoptosis and cause cell cycle arrest. The expression of the marker proteins, such as PARP and caspase 3, were notably effected by this compound, thus inducing apoptosis. In conclusion, our investigation implied that compound 14 may serve as a potential anti-leukemia agent.

Anticancer activity features of imidazole-based ionic liquids and lysosomotropic detergents: in silico and in vitro studies.

Long-chain imidazole-based ionic liquids (compounds 2, 4, 9) and lysosomotropic detergents (compounds 7, 3, 8) with potent anticancer activity were synthesized. Their inhibitory activities against neuroblastoma and leukaemia cell lines were predicted by the new in silico QSAR models. The cytotoxic activities of the synthesized imidazole derivatives were investigated on the SK-N-DZ (human neuroblastoma) and K-562 (human chronic myeloid leukaemia) cell lines. Compounds 2 and 7 showed the highest in vitro cytotoxic effect on both cancer cell lines. The docking procedure of compounds 2 and 7 into the NAD+ coenzyme binding site of deacetylase Sirtuin-1 (SIRT-1) showed the formation of protein-ligand complexes with calculated binding energies of -8.0 and - 8.1kcal/mol, respectively. The interaction of SIRT1 with compounds 2, 7 and 9 and the interaction of Bromodomain-containing protein 4 (BRD4) with compounds 7 and 9 were also demonstrated by thermal shift assay. Compounds 2, 4, 7 and 9 inhibited SIRT1 deacetylase activity in the SIRT-Glo assay. Compounds 7 and 9 showed a moderate inhibitory activity against Aurora kinase A. In addition, compounds 3, 4, 8 and 9 inhibited the Janus kinase 2 activity. The results obtained showed that long-chain imidazole derivatives exhibited cytotoxic activities on K562 leukaemia and SK-N-DZ neuroblastoma cell lines. Furthermore, these compounds inhibited a panel of molecular targets involved in leukaemia and neuroblastoma tumorigenesis. All these results suggest that both long-chain imidazole-based ionic liquids and lysosomotropic detergents may be an effective alternative for the treatment of neuroblastoma and chronic myeloid leukemia and merit further investigation.

Sulfated polysaccharides from the viscera of Mustelus shark: Characterization and antioxidant, anticoagulant and anti-proliferative activities

In the present study, sulfated polysaccharides (SPs) from smooth hound shark were extracted using different precipitation agents, the cetylpyridinium chloride (CPC) or ethanol, named SHSP-I and SHSP-II, respectively. The UV–visible scan demonstrated the absence of nucleic acids or proteins in the extracted SHSPs. The antioxidant, anticoagulant and anti-proliferative activities were also investigated. Results showed that SHSPs displayed reducing and scavenging capacities, as shown by the oxygen radical absorbance capacity, the total antioxidant capacity and the hydroxyl radical-scavenging activities. Moreover, extracted SPs were able to prolong the activated partial thromboplastin time (aPTT), the prothrombin time (PT) and the thrombin time (TT) and they reduced the fibrinogen level (FL), without inducing erythrocytes hemolysis, which indicated that they inhibited the intrinsic and extrinsic coagulation pathways and the thrombin-mediated fibrin formation. The SHSP-I was more effective on prolonging the blood clotting time, by more than 120 s at 1 mg/ml in the aPTT and about 70 s and 60 s at 2.5 mg/ml in the PT and TT, respectively, compared to the SHSP-II. The anti-proliferative activity of SHSPs was tested against the growth of K562 human myelogenous leukemia cells and Caco-2 colon cancer cells. Data showed that both polysaccharides have a dose-dependent inhibitory effect, where SHSP-I exhibited the strongest activity against the tested cells and the K562 was more sensitive than Caco-2 line cells to the action of SHSPs. The overall data suggested that SPs from shark viscera could be useful as natural nutraceutical agents.

Biological evaluation of combinations of tyrosine kinase inhibitors with Inecalcitol as novel treatments for human chronic myeloid leukemia

BackgroundThe use of tyrosine kinase inhibitors (TKIs) as a treatment for chronic myeloid leukemia (CML) has improved the natural history of the disease and increased the duration of survival. Tyrosine kinase inhibitors represent the success of target therapies that work on molecular targets, although some patients still have therapy failure. Vitamin D has antiproliferative, pro-apoptotic, and anti-angiogenic effects on cells, therefore it can be considered as a potential cancer preventative and treatment agent. Inecalcitol (TX-522) is the 14-epi-analogue of Calcitriol (1,25(OH)2-vitamin D3), and inhibits cancer cell proliferation more effectively than Calcitriol. This study was conducted to evaluate the antiproliferative and synergistic effects of the anticancer drugs Imatinib and Dasatinib in combinations with Inecalcitol on human chronic myeloid leukemia K-562 cells. MethodThe growth inhibitory activities of Inecalcitol, Imatinib, Dasatinib, and different combinations of one of the two drugs (Imatinib and Dasatinib) with Inecalcitol, were determined in vitro using MTT assay against K-562 cell line. ResultsInecalcitol, Imatinib, and Dasatinib showed potent antiproliferative activities against K-562 cells with GI50 values of 5.6 µM, 0.327 µM, and 0.446 nM, respectively. Combinations of Imatinib or Dasatinib with different concentrations of Inecalcitol increased significantly the antiproliferative activities and potencies of both drugs (****p < 0.0001), with optimal GI50 values of 580 pM (Imatinib) and 0.51 pM (Dasatinib). Furthermore, the combination treatments showed synergistic interaction between the antileukemic drugs and Inecalcitol, with combination indices (CI) < 1. ConclusionThe study demonstrated that the human chronic myeloid leukemia K-562 cells were subjected to a synergistic growth inhibitory impact when antileukemic drugs (Imatinib or Dasatinib) were combined with Inecalcitol, therefore, it is recommended that these combinations be viewed as promising novel antileukemic medications and used in place of individual medications with lower dosages and negligible side effects in the treatment of CML.

Three snake venoms from Bothrops genus induced apoptosis and cell cycle arrest in K562 human leukemic cell line

Cancer is indisputably one of the leading causes of death worldwide. Snake venoms are a potential source of bioactive compounds, complex mixtures constituted mainly of proteins and peptides with several pharmacological possibilities, including the potential to inhibit tumoral cell growth. In the present study, it was evaluated the antitumor effect of crude venom of Bothrops erythromelas (BeV), Bothrops jararaca (from Southern and Southeastern- BjsV and BjsdV, respectively) and Bothrops alternatus (BaV) in in vitro Chronic myeloid leukemia (CML) cancer cell line model. After 24 h of cell exposure to 10 and 50 μg/mL, BjsV, BjsdV, and BaV exerted a decrease in cell viability in both concentrations. BeV was not cytotoxic and, therefore wasn’t chosen for further mechanism of action investigation. Furthermore, morphological alterations show modification typical of apoptosis. Also, was observes a significant cell cycle arrest in the S phase by BjsdV and BaV treatment. Flow cytometry evidenced the involvement of changes in the cell membrane permeability and the mitochondrial function by BjsV and BjsdV, corroborating with the triggering of the apoptotic pathway by the venom administration. BjsV, BjsdV, and BaV also led to extensive DNA damage and were shown to modulate the gene expression of transcripts related to the cell cycle progression and suppress the expression of the BCR-ABL1 oncogene. Altogether, these findings suggest that the venoms trigger the apoptosis pathway due to mitochondrial damage and cell cycle arrest, with modulation of intracellular pathways important for CML progression. Thus, indicating the pharmacological potential of these venoms in the development of new antitumoral compounds.

Design, synthesis and bioevaluation of novel prenylated chalcones derivatives as potential antitumor agents

A series of novel prenylated chalcone derivatives with broad spectrum anticancer potential were designed and synthesized. Some of the synthesized target compounds showed potent anti-proliferative activities toward LNCaP (prostate cancer cell line), K562 (human leukemia cells), A549 (human lung carcinoma cell line) and HeLa (cervical cancer cell line) cell lines. Among of the active compounds, (E)-1-(4-(2-(diethylamino)ethoxy)-2-hydroxy-6-methoxy-3-(3-methylbut-2-en-1-yl)phenyl)-3-(pyridin-3-yl)prop-2-en-1-one (C36) was directly interacted with protein kinase B (PKB), also known as AKT, significantly inhibited the pPI3K, pAKT(Ser473) protein levels to repress the growth of cancer cells by inducing apoptosis, arresting cell cycle. Our studies provide support for prenylated chalcone derivatives potential applications in cancer treatment as a potential AKT inhibitor.

A Cytochrome c Variant Enhances Megakaryocytic Maturation

Mutations in genes which play a role in the processes of megakaryopoiesis and platelet production cause thrombocytopenia. Five pathogenic variants in the gene encoding cytochrome c ( CYCS) associated with mild autosomal dominant thrombocytopenia have been reported. The role of cytochrome c in megakaryopoiesis and platelet formation is unknown, and it is unclear how mutations in cytochrome c cause thrombocytopenia. The goal of this project is to understand how CYCS mutations cause thrombocytopenia. We are using the human leukemic K562 cell line as a model system to study the impact of CYCS mutations on megakaryocyte differentiation and mitochondrial function. One of the CYCS pathogenic variants (c.145T&amp;gt;C; p.Tyr49His) was introduced into K562 cells using the CRISPR-Cas9 base-editing method. K562 cells have three copies of CYCS-containing chromosome 7 and we isolated CYCS WT/WT/WT, CYCS WT/WT/Y49H, CYCS WT/Y49H/Y49H, CYCS Y49H/Y49H/Y49H clonal lines, confirmed by sequencing and mass spectrometry. K562 cells undergo megakaryocyte differentiation in response to PMA. We monitored the expression of megakaryocyte markers CD61 and CD41a by flow cytometry in response to PMA in all clonal lines. The K562- CYCS Y49H/Y49H/Y49H line showed faster maturation compared to all other clonal lines and the parental K562 cells. We assessed mitochondrial function using the Seahorse XFe96 Analyzer. Our results show that the mutation does not impact mitochondrial respiratory function. Finally, we have introduced the Y49H mutation into WTC11 iPSCs. Investigations of the impact of the Y49H variant on apoptosis showed that there is no significant differences in apoptosis between WT and the clonal line carrying the Y49H variant. Our results suggest that the pathogenic c.145T&amp;gt;C; p.Tyr49His CYCS variant enhances megakaryocyte maturation.