Exosome application in treatment and diagnosis of B-cell disorders: leukemias, multiple sclerosis, and arthritis rheumatoid.

Exosomes, known as a type of extracellular vesicles (EVs), are lipid particles comprising heterogeneous contents such as nucleic acids, proteins, and DNA. These bi-layered particles are naturally released into the extracellular periphery by a variety of cells such as neoplastic cells. Given that exosomes have unique properties, they can be used as vectors and carriers of biological and medicinal particles like drugs for delivering to the desired areas. The proteins and RNAs being encompassed by the circulating exosomes in B-cell malignancies are deemed as the promising sources for diagnostic and prognostic biomarkers, as well as therapeutic agents. Exosomes can also provide a "snapshot" view of the tumor and metastatic landscape at any particular time. Further, clinical research has shown that exosomes are produced by immune cells such as dendritic cells can stimulate the immune system, so these exosomes can be used in antitumor vaccines. Despite the great potential of exosomes in the fields of diagnostic and treatment, further studies are in need for these purposes to reach a convergence notion. This review highlights the applications of exosomes in multiple immune-related diseases, including chronic lymphocytic leukemia, multiple sclerosis, and arthritis rheumatoid, as well as explaining sundry aspects of exosome therapy and the function of exosomes in diagnosing diseases.

[Effect of miltirone on proliferation and apoptosis of leukemia THP-1 cells].

To investigate the toxicity and related mechanism of miltirone to human acute myeloid leukemia THP-1 cells. To be specific, the active components and targets of miltirone were retrieved from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP), and the target proteins were converted into standard gene names with UniProt. Acute leukemia-rela-ted target genes were screened from GeneCards and DisGeNET. Venn diagram was constructed with Venny 2.1 to yield the common targets of the disease and the drug. The protein-protein interaction(PPI) network was constructed by STRING and Cytoscape 3.8.2. THP-1 cells in the logarithmic growth phase were treated with dimethyl sulfoxide(DMSO), and 2.5, 5, 10, 15, and 20 µmol·L~(-1) miltirone for 24 h, respectively. The proliferation rate of cells was analyzed by carboxyfluorescein diacetate succinimidyl ester(CFSE), apoptosis rate by flow cytometry with Annexin V-PE/7 AAD staining, and cell morphology by acridine orange staining. Real-time quantitative PCR(qPCR) was employed to detect the mRNA levels of nuclear receptor coactivator 2(NCOA2), poly(ADP-ribose) polymerase-1(PARP1), B-cell lymphoma-2(Bcl-2)-associated X protein(Bax), Bcl-2, and cysteine aspartyl protease-3(caspase-3). The effect of miltirone on apoptosis was detected in presence of caspase inhibitor Z-VAD-FMK. A total of 26 targets of miltirone, 1 046 genes related to acute leukemia, and 6 common targets of the two were screened out. Flow cytometry result showed miltirone at 10 µmol·L~(-1) can inhibit proliferation and promote apoptosis of THP-1 cells. The typical manifestations of apoptosis, such as cell shrinkage, nuclear rupture, and chromatin agglomerate were displayed by acridine orange staining. The decreased mRNA levels of NCOA2 and PARP1 and increased Bax/Bcl-2 ratio and the activity of pro-apoptotic protein caspase-3 were observed. Z-VAD-FMK can attenuate the apoptosis-inducing effect of miltirone. This study indicates that miltirone can inhibit the proliferation and promote the apoptosis of THP-1 cells, by down-regulating NCOA2 and PARP1, raising Bax/Bcl-2 ratio, and activating caspase-3.

Effect of miltirone on proliferation and apoptosis of leukemia THP-1 cells / 中国中药杂志

To investigate the toxicity and related mechanism of miltirone to human acute myeloid leukemia THP-1 cells. To be specific, the active components and targets of miltirone were retrieved from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP), and the target proteins were converted into standard gene names with UniProt. Acute leukemia-rela-ted target genes were screened from GeneCards and DisGeNET. Venn diagram was constructed with Venny 2.1 to yield the common targets of the disease and the drug. The protein-protein interaction(PPI) network was constructed by STRING and Cytoscape 3.8.2. THP-1 cells in the logarithmic growth phase were treated with dimethyl sulfoxide(DMSO), and 2.5, 5, 10, 15, and 20 μmol·L~(-1) miltirone for 24 h, respectively. The proliferation rate of cells was analyzed by carboxyfluorescein diacetate succinimidyl ester(CFSE), apoptosis rate by flow cytometry with Annexin V-PE/7 AAD staining, and cell morphology by acridine orange staining. Real-time quantitative PCR(qPCR) was employed to detect the mRNA levels of nuclear receptor coactivator 2(NCOA2), poly(ADP-ribose) polymerase-1(PARP1), B-cell lymphoma-2(Bcl-2)-associated X protein(Bax), Bcl-2, and cysteine aspartyl protease-3(caspase-3). The effect of miltirone on apoptosis was detected in presence of caspase inhibitor Z-VAD-FMK. A total of 26 targets of miltirone, 1 046 genes related to acute leukemia, and 6 common targets of the two were screened out. Flow cytometry result showed miltirone at 10 μmol·L~(-1) can inhibit proliferation and promote apoptosis of THP-1 cells. The typical manifestations of apoptosis, such as cell shrinkage, nuclear rupture, and chromatin agglomerate were displayed by acridine orange staining. The decreased mRNA levels of NCOA2 and PARP1 and increased Bax/Bcl-2 ratio and the activity of pro-apoptotic protein caspase-3 were observed. Z-VAD-FMK can attenuate the apoptosis-inducing effect of miltirone. This study indicates that miltirone can inhibit the proliferation and promote the apoptosis of THP-1 cells, by down-regulating NCOA2 and PARP1, raising Bax/Bcl-2 ratio, and activating caspase-3.

Alterations in sphingolipid composition and mitochondrial bioenergetics represent synergistic therapeutic vulnerabilities linked to multidrug resistance in leukemia.

Modifications in sphingolipid (SL) metabolism and mitochondrial bioenergetics are key factors implicated in cancer cell response to chemotherapy, including chemotherapy resistance. In the present work, we utilized acute myeloid leukemia (AML) cell lines, selected to be refractory to various chemotherapeutics, to explore the interplay between SL metabolism and mitochondrial biology supportive of multidrug resistance (MDR). In agreement with previous findings in cytarabine or daunorubicin resistant AML cells, relative to chemosensitive wildtype controls, HL-60 cells refractory to vincristine (HL60/VCR) presented with alterations in SL enzyme expression and lipidome composition. Such changes were typified by upregulated expression of various ceramide detoxifying enzymes, as well as corresponding shifts in ceramide, glucosylceramide, and sphingomyelin (SM) molecular species. With respect to mitochondria, despite consistent increases in both basal respiration and maximal respiratory capacity, direct interrogation of the oxidative phosphorylation (OXPHOS) system revealed intrinsic deficiencies in HL60/VCR, as well as across multiple MDR model systems. Based on the apparent requirement for augmented SL and mitochondrial flux to support the MDR phenotype, we explored a combinatorial therapeutic paradigm designed to target each pathway. Remarkably, despite minimal cytotoxicity in peripheral blood mononuclear cells (PBMC), co-targeting SL metabolism, and respiratory complex I (CI) induced synergistic cytotoxicity consistently across multiple MDR leukemia models. Together, these data underscore the intimate connection between cellular sphingolipids and mitochondrial metabolism and suggest that pharmacological intervention across both pathways may represent a novel treatment strategy against MDR.

Environmental pollutant ENU induced leukemic NF-kB signaling amelioration by Eclipta alba in murine model.

Exposure to N-nitroso compounds (NOCs) in our environment via pesticides, tobacco, and smoked meat can be potentially carcinogenic. The induction of N-N' ethylnitrosourea (ENU), a genotoxic NOC, leads to leukemogenesis. The study aimed to explore the ameliorating effect of the Ayurvedic herb Eclipta alba on the bone marrow cells of ENU-induced leukemic mice. Eclipta alba is investigated for its anti-cancer effect on various cell lines, but never on haematological malignant models. Theefficacy of the extract was explored on leukemia by changes in body weight, survivability, peripheral blood hemogram, bone marrow cytological, histological, and cell culture studies pre-and post-treatment. The treated group revealed significant immunomodulation of the expressional profile of NF-kB family and IL-1ß in marrow cells, by flow-cytometry, and immunofluorescence study. Through our experimental endeavour we depicted the cellular mechanism, signaling modality and tried to establish the anti-cancer potency of Eclipta alba on ENU-induced leukemia.

Kynurenine pathway activation and deviation to anthranilic and kynurenic acid in fibrosing chronic graft-versus-host disease.

Fibrosing chronic graft-versus-host disease (cGVHD) is a debilitating complication of allogeneic stem cell transplantation (alloSCT). A driver of fibrosis is the kynurenine (Kyn) pathway, and Kyn metabolism patterns and cytokines may influence cGVHD severity and manifestation (fibrosing versus gastrointestinal [GI] cGVHD). Using a liquid chromatography-tandem mass spectrometry approach on sera obtained from 425 patients with allografts, we identified high CXCL9, high indoleamine-2,3-dioxygenase (IDO) activity, and an activated Kyn pathway as common characteristics in all cGVHD subtypes. Specific Kyn metabolism patterns could be identified for non-severe cGVHD, severe GI cGVHD, and fibrosing cGVHD, respectively. Specifically, fibrosing cGVHD was associated with a distinct pathway shift toward anthranilic and kynurenic acid, correlating with reduced activity of the vitamin-B2-dependent kynurenine monooxygenase, low vitamin B6, and increased interleukin-18. The Kyn metabolite signature is a candidate biomarker for severe fibrosing cGVHD and provides a rationale for translational trials on prophylactic vitamin B2/B6 supplementation for cGVHD prevention.

Pros and Cons of the Cannabinoid System in Cancer: Focus on Hematological Malignancies.

The endocannabinoid system (ECS) is a composite cell-signaling system that allows endogenous cannabinoid ligands to control cell functions through the interaction with cannabinoid receptors. Modifications of the ECS might contribute to the pathogenesis of different diseases, including cancers. However, the use of these compounds as antitumor agents remains debatable. Pre-clinical experimental studies have shown that cannabinoids (CBs) might be effective for the treatment of hematological malignancies, such as leukemia and lymphoma. Specifically, CBs may activate programmed cell death mechanisms, thus blocking cancer cell growth, and may modulate both autophagy and angiogenesis. Therefore, CBs may have significant anti-tumor effects in hematologic diseases and may synergistically act with chemotherapeutic agents, possibly also reducing chemoresistance. Moreover, targeting ECS might be considered as a novel approach for the management of graft versus host disease, thus reducing some symptoms such as anorexia, cachexia, fatigue, anxiety, depression, and neuropathic pain. The aim of the present review is to collect the state of the art of CBs effects on hematological tumors, thus focusing on the essential topics that might be useful before moving into the clinical practice.

Pharmacological mechanism of mylabris in the treatment of leukemia based on bioinformatics and systematic pharmacology.

Leukemia is a common blood cancer, whose treatment usually necessitates chemo/radiotherapy and bone marrow transplant. Hence, safer and more effective options are urgently needed. Mylabris, the dried body of blister beetles, has been used extensively in traditional Chinese medicine. This study applied bioinformatics and systematic pharmacology to investigate the mechanism of action of mylabris in the treatment of leukemia. Five effective components and 35 corresponding target proteins were identified by screening the TCMSP database; whereas 776 genes related to leukemia were selected using OMIM, GeneCards, and the Therapeutic Target Database. Eight genes common to mylabris and leukemia were identified. Protein-protein interaction network analysis and a component-target-pathway diagram identified TP53 and PTEN as key gene targets of mylabris in the treatment of leukemia. GO enrichment analysis pointed to DNA damage and cell cycle disorder caused by p53 signaling as the most significant processes; whereas KEGG enrichment pointed to the p53 signaling pathway. In summary, mylabris may exert a therapeutic effect on leukemia by triggering DNA damage, inducing apoptosis, as well as inhibiting the growth and proliferation of tumor cells through the regulation of TP53 and PTEN. These findings provide a mechanistic rationale for the treatment of leukemia with traditional Chinese medicine.

Apoptotic mechanisms of myricitrin isolated from Madhuca longifolia leaves in HL-60 leukemia cells.

Myricitrin, a naturally occurring flavonoid in Madhuca longifolia, possesses several medicinal properties. Even though our earlier work revealed its role against the proliferation of acute myelogenous leukemia cells (HL-60), its molecular mechanisms have not yet been revealed. The current study aims to explore the molecular mechanisms of myricitrin (isolated from an ethnomedicinal drug Madhuca longifolia) to induce apoptosis in HL-60 cells. Treatment with IC-50 dose of myricitrin (353 µM) caused cellular shrinkage and cell wall damage in HL-60 cells compared to untreated control cells. Myricitrin treatment reduced the mitochondrial membrane potential (22.95%), increased DNA fragmentation (90.4%), inhibited the cell survival proteins (RAS, B-RAF, & BCL-2) and also induced pro-apoptotic proteins (p38, pro-caspase-3, pro-caspase-9 and caspase-3) in the HL-60 cells. The present study provides scientific evidence for the apoptosis caused by myricitrin in HL-60 leukemia cells. Hence, the phytochemical myricitrin could be considered as a potential candidate to develop an anticancer drug after checking its efficacy through suitable pre-clinical and clinical studies.

Tanshinone I, a new EZH2 inhibitor restricts normal and malignant hematopoiesis through upregulation of MMP9 and ABCG2.

Rationale: Tanshinone, a type of diterpenes derived from salvia miltiorrhiza, is a particularly promising herbal medicine compound for the treatment of cancers including acute myeloid leukemia (AML). However, the therapeutic function and the underlying mechanism of Tanshinone in AML are not clear, and the toxic effect of Tanshinone limits its clinical application. Methods: Our work utilizes human leukemia cell lines, zebrafish transgenics and xenograft models to study the cellular and molecular mechanisms of how Tanshinone affects normal and abnormal hematopoiesis. WISH, Sudan Black and O-Dianisidine Staining were used to determine the expression of hematopoietic genes on zebrafish embryos. RNA-seq analysis showed that differential expression genes and enrichment gene signature with Tan I treatment. The surface plasmon resonance (SPR) method was used with a BIAcore T200 (GE Healthcare) to measure the binding affinities of Tan I. In vitro methyltransferase assay was performed to verify Tan I inhibits the histone enzymatic activity of the PRC2 complex. ChIP-qPCR assay was used to determine the H3K27me3 level of EZH2 target genes. Results: We found that Tanshinone I (Tan I), one of the Tanshinones, can inhibit the proliferation of human leukemia cells in vitro and in the xenograft zebrafish model, as well as the normal and malignant definitive hematopoiesis in zebrafish. Mechanistic studies illustrate that Tan I regulates normal and malignant hematopoiesis through direct binding to EZH2, a well-known histone H3K27 methyltransferase, and inhibiting PRC2 enzymatic activity. Furthermore, we identified MMP9 and ABCG2 as two possible downstream genes of Tan I's effects on EZH2. Conclusions: Together, this study confirmed that Tan I is a novel EZH2 inhibitor and suggested MMP9 and ABCG2 as two potential therapeutic targets for myeloid malignant diseases.

Anticancer and Anti-inflammatory Effect of Diosmin against Dalton Ascitic Lymphoma Induced Leukemia.

Cancer is the world's biggest health problem and cancer-induced mortality happened all over the planet after the heart disease. The present study was to scrutinize the anti-leukemia effect of diosmin against Dalton Ascitic Lymphoma (DAL) induced leukemia in mice. DAL cell was used for induction the solid tumor. Body weight, life spans, tumor volume and mean survival time was estimated. Antioxidant, biochemical and pro-inflammatory cytokines were estimated. Diosmin showed the cell viability effect at dose dependent manner against the both cell lines. DAL induced solid tumor mice showed the decreased body weight, mean survival days, non viable cell count and increased the tumor volume, viable cell count and diosmin significantly (p < 0.001) reverse the effect of DAL. Diosmin significantly (p < 0.001) altered the hematological, differential leukocytes, antioxidant, biochemical, pro-inflammatory cytokines at dose dependently. Collectively, we can say that diosmin might alter the DAL induced abnormality via antioxidant and anti-inflammatory effects.

A novel peptide isolated from garlic shows anticancer effect against leukemic cell lines via interaction with Bcl-2 family proteins.

Leukemia is a group of cancer caused by the abnormal proliferation and differentiation of hematopoietic stem cells. Efforts geared toward effective therapeutic strategies with minimal side effects are underway. Peptides derived from natural resources have recently gained special attention as alternative chemotherapeutic agents due to their minimal adverse effects. In the present study, the aim was to isolate peptides from garlic (Allium sativum) and investigate their anticancer activity against leukemic cell lines. The protein extract of A. sativum was pepsin-digested to obtain protein hydrolysate followed by sequential purification methods. A novel anticancer peptide, VKLRSLLCS (VS-9), was identified and characterized by mass spectrometric analysis. The peptide was demonstrated to significantly inhibit the cell proliferation of MOLT-4 and K562 leukemic cell lines while exhibiting minimal inhibition against normal PBMC. Particularly, VS-9 could induce apoptosis and upregulate mRNA levels of caspase 3, caspase 8, caspase 9, and Bax while downregulating Bcl-2, Bcl-xL, and Bcl-w. Molecular docking of VS-9 with the anti-apoptotic Bcl-2 protein family suggested that VS-9 could bind the binding groove of the BH3 domain on target proteins. Protein-peptide interaction analysis by affinity chromatography and LC-MS/MS further showed that VS-9 could bind Bcl-2 proteins. Results suggest VS-9 as a potential garlic-derived novel anticancer peptide possessing apoptosis-inducing properties against leukemic cell lines via anti-apoptotic Bcl-2 protein family.

Antileukemic effect of caffeic acid 3,4-dihydroxyphenetyl ester. Evidences for its mechanisms of action.

BACKGROUND: Caffeic acid 3,4-dihydroxyphenethyl ester (CADPE) is a natural polyphenolic ester isolated as a minor component from a water extract of the Chinese medicine Zhongjiefeng [Sarcandra glabra (Thunb.) Nakai (Chloranthaceae)] and has previously shown to have activity against solid tumors through the modulation of multiple targets or signal pathways. However, the activity and potential mechanism of CADPE against leukemia cells have not yet been characterized. PURPOSE: To investigate whether and how CADPE kills leukemia cells. METHOD: (1) The activity of CADPE inhibiting the growth of different leukemia cell lines was evaluated by MTT assay; (2) Cell cycle arrest and apoptosis induced by CADPE were determined by flow cytometry with FlowJo software for quantification; (3) The protein levels were analyzed by Western blot and ubiquitin-binding c-Myc was acquired by co-immunoprecipitation. RESULTS: CADPE exerted potent activity against different leukemia cell lines with low toxicity in normal cells. In terms of mechanism of action, CADPE promoted ubiquitin-proteasome-dependent degradation of c-Myc through activating glycogen synthase kinase-3ß (GSK3ß) and downregulating deubiquitinating enzyme USP28 to trigger the interaction of c-Myc with ubiquitin ligase Fbw7, resulting in the downregulation of cell cycle regulators and anti-apoptotic proteins and consequently, cell cycle arrest and cell apoptosis. CONCLUSION: CADPE is a novel c-Myc inhibitor with high activity and a unique mechanism for killing leukemia cells.

Cytotoxic and Antiproliferative Effects of Diarylheptanoids Isolated from Curcuma comosa Rhizomes on Leukaemic Cells.

Curcuma comosa belongs to the Zingiberaceae family. In this study, two natural compounds were isolated from C. comosa, and their structures were determined using nuclear magnetic resonance. The isolated compounds were identified as 7-(3,4-dihydroxyphenyl)-5-hydroxy-1-phenyl-(1E)-1-heptene (1) and trans-1,7-diphenyl-5-hydroxy-1-heptene (2). Compound 1 showed the strongest cytotoxicity effect against HL-60 cells, while its antioxidant and anti-inflammatory properties were stronger than those of compound 2. Compound 1 proved to be a potent antioxidant, compared to ascorbic acid. Neither compounds had any effect on red blood cell haemolysis. Furthermore, compound 1 significantly decreased Wilms' tumour 1 protein expression and cell proliferation in KG-1a cells. Compound 1 decreased the WT1 protein levels in a time- and dose- dependent manner. Compound 1 suppressed cell cycle at the S phase. In conclusion, compound 1 has a promising chemotherapeutic potential against leukaemia.

Induction of Apoptosis, Autophagy and Ferroptosis by Thymus vulgaris and Arctium lappa Extract in Leukemia and Multiple Myeloma Cell Lines.

Thymus vulgaris and Arctium lappa have been used as a folk remedy in the Iraqi Kurdistan region to deal with different health problems. The aim of the current study is to investigate the cytotoxicity of T. vulgaris and A. lappa in leukemia and multiple myeloma (MM) cell lines and determine the mode of cell death triggered by the most potent cytotoxic fractions of both plants in MM. Resazurin assay was used to evaluate cytotoxic and ferroptosis activity, apoptosis, and modulation in the cell cycle phase were investigated via Annexin V-FITC/PI dual stain and cell-cycle arrest assays. Furthermore, we used western blotting assay for the determination of autophagy cell death. n-Hexane, chloroform, ethyl acetate, and butanol fractions of T. vulgaris and A. lappa exhibited cytotoxicity in CCRF-CEM and CEM/ADR 5000 cell lines at concentration range 0.001-100 µg/mL with potential activity revealed by chloroform and ethyl acetate fractions. NCI-H929 displayed pronounced sensitivity towards T. vulgaris (TCF) and A. lappa (ACF) chloroform fractions with IC50 values of 6.49 ± 1.48 and 21.9 ± 0.69 µg/mL, respectively. TCF induced apoptosis in NCI-H929 cells with a higher ratio (71%), compared to ACF (50%) at 4 × IC50. ACF demonstrated more potent autophagy activity than TCF. TCF and ACF induced cell cycle arrest and ferroptosis. Apigenin and nobiletin were identified in TCF, while nobiletin, ursolic acid, and lupeol were the main compounds identified in ACF. T. vulgaris and A. lappa could be considered as potential herbal drug candidates, which arrest cancer cell proliferation by induction of apoptosis, autophagic, and ferroptosis.

Chemopreventive Property of Sencha Tea Extracts towards Sensitive and Multidrug-Resistant Leukemia and Multiple Myeloma Cells.

The popular beverage green tea possesses chemopreventive activity against various types of tumors. However, the effects of its chemopreventive effect on hematological malignancies have not been defined. In the present study, we evaluated antitumor efficacies of a specific green tea, sencha tea, on sensitive and multidrug-resistant leukemia and a panel of nine multiple myelomas (MM) cell lines. We found that sencha extracts induced cytotoxicity in leukemic cells and MM cells to different extents, yet its effect on normal cells was limited. Furthermore, sencha extracts caused G2/M and G0/G1 phase arrest during cell cycle progression in CCRF/CEM and KMS-12-BM cells, respectively. Specifically, sencha-MeOH/H2O extracts induced apoptosis, ROS, and MMP collapse on both CCRF/CEM and KMS-12-BM cells. The analysis with microarray and COMPARE in 53 cell lines of the NCI panel revealed diverse functional groups, including cell morphology, cellular growth and proliferation, cell cycle, cell death, and survival, which were closely associated with anti-tumor effects of sencha tea. It is important to note that PI3K/Akt and NF-κB pathways were the top two dominant networks by ingenuity pathway analysis. We demonstrate here the multifactorial modes of action of sencha tea leading to chemopreventive effects of sencha tea against cancer.

Cytotoxic activity of dimeric acridone alkaloids derived from Citrus plants towards human leukaemia HL-60 cells.

OBJECTIVES: Acridone alkaloids from Citrus and their derivatives show various kinds of biological activity. However, the anticancer activities of dimeric acridone alkaloids with unique structures and the molecular mechanism of these effects are poorly understood. METHODS: We investigated the cytotoxicity effects of dimeric acridone alkaloids isolated from Marsh grapefruit on human myeloid leukaemia HL-60 cells. KEY FINDINGS: Of the six dimeric acridone alkaloids tested, citbismine-E, the most potent, dose- and time-dependently decreased HL-60 cell viability by inducing apoptosis. The treatment of HL-60 cells with citbismine-E yielded a significant increase in levels of intracellular reactive oxygen species (ROS). Citbismine-E lowered the mitochondrial membrane potential and increased the activities of caspase-9 and -3. In addition, citbismine-E-induced apoptosis, decrease in mitochondrial membrane potential and caspase activation were significantly alleviated by pretreatment of the cells with antioxidant N-acetylcysteine (NAC). Citbismine-E induced intrinsic caspase-dependent apoptosis through ROS-mediated c-Jun N-terminal kinase activation. Citbismine-E-induced production of oxidative stress biomarkers, malondialdehyde and 8-hydroxy-2'-deoxyguanosine was also attenuated by pretreatment with NAC. CONCLUSIONS: Citbismine-E is a powerful cytotoxic agent against HL-60 cells that acts by inducing mitochondrial dysfunction-mediated apoptosis through ROS-dependent JNK activation. Citbismine-E also induced oxidative stress damage via ROS-mediated lipid peroxidation and DNA damage in HL-60 cells.

Novel therapeutic strategies for MLL-rearranged leukemias.

MLL rearrangement is one of the key drivers and generally regarded as an independent poor prognostic marker in acute leukemias. The standard of care for MLL-rearranged (MLL-r) leukemias has remained largely unchanged for the past 50 years despite unsatisfying clinical outcomes, so there is an urgent need for novel therapeutic strategies. An increasing body of evidence demonstrates that a vast number of epigenetic regulators are directly or indirectly involved in MLL-r leukemia, and they are responsible for supporting the aberrant gene expression program mediated by MLL-fusions. Unlike genetic mutations, epigenetic modifications can be reversed by pharmacologic targeting of the responsible epigenetic regulators. This leads to significant interest in developing epigenetic therapies for MLL-r leukemia. Intriguingly, many of the epigenetic enzymes also involve in DNA damage response (DDR), which can be potential targets for synthetic lethality-induced therapies. In this review, we will summarize some of the recent advances in the development of epigenetic and DDR therapeutics by targeting epigenetic regulators or protein complexes that mediate MLL-r leukemia gene expression program and key players in DDR that safeguard essential genome integrity. The rationale and molecular mechanisms underpinning the therapeutic effects will also be discussed with a focus on how these treatments can disrupt MLL-fusion mediated transcriptional programs and impair DDR, which may help overcome treatment resistance.

Curcumin augments therapeutic efficacy of TRAIL-based immunotoxins in leukemia.

BACKGROUND: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) has been perceived as a promising anti-cancer agent because of its unique ability to kill cancer cells while sparing normal cells. However, translation of TRAIL to clinical studies was less successful as a large number of cancer cells acquire resistance to TRAIL-based monotherapies. An ideal strategy to overcome TRAIL resistance is to combine it with potential sensitizing agents. OBJECTIVE: To investigate the TRAIL-sensitizing effect of curcumin in leukemia. METHODS: The mechanism underlying TRAIL sensitization by curcumin was studied by flow cytometric analysis of TRAIL receptors in leukemic cell lines and patient samples, and immunoblot detection of TRAIL-apoptosis signaling proteins. RESULTS: Curcumin augments TRAIL-apoptotic signaling in leukemic cells by upregulating the expression of DR4 and DR5 along with suppression of cFLIP and anti-apoptotic proteins Mcl-1, Bcl-xl, and XIAP. Curcumin pre-treatment significantly (p < 0.01) enhanced the sensitivity of leukemic cell lines to TRAIL recombinant proteins. IL2-TRAIL peptide in the presence of curcumin induced potent apoptosis (p < 0.001) as compared to TRAIL and IL2-TRAIL protein in leukemic cell lines with IC50 < 0.1 µΜ. Additionally, the combination of IL2-TRAIL peptide and curcumin showed significant cytotoxicity in patient peripheral blood mononuclear cells (PBMCs) with an efficacy of 90% in acute myeloid leukemia (AML), but 100% in acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL) and chronic myelomonocytic leukemia (CMML). CONCLUSION: Overall, our results suggest that curcumin potentiates TRAIL-induced apoptosis through modulation of death receptors and anti-apoptotic proteins which significantly enhances the therapeutic efficacy.

Oxidative stress mediated cytotoxicity in leukemia cells induced by active phyto-constituents isolated from traditional herbal drugs of West Bengal.

ETHNOPHARMACOLOGICAL RELEVANCE: In search of safe and effective therapeutic agents as alternative to synthetic chemotherapeutics for the treatment of leukemia, the herbal drugs (Leaf of Madhuca longifolia, leaf of Prosopis cineraria and bark of Flacourtia indica) with long traditional use in West Bengal have received our attention. AIM OF THE STUDY: Present work was conducted to isolate and identify the active compounds of the selected herbal drugs using bio-assay guided fractionation and also to investigate their anticancer mechanism in leukemia cell lines. MATERIALS AND METHODS: Bio-assay guided fractionation was used for the isolation of active constituents such as myricitrin, vitexin and vanillin from the aqueous extracts of M. longifolia, P. cineraria and F. indica, respectively using liquid partitioning and column chromatography and the compounds were characterized by HPLC, MS and NMR. Dose and time-dependent cytotoxicity of isolated compounds were studied against leukemia cells and their anticancer mechanism such as cell wall damage, nuclear damage, ROS and NO generation, SOD level, LDH release and lipid peroxidation were investigated. RESULTS: Aqueous extract of M. longifolia, P. cineraria and F. indica exhibited maximum anti-proliferative activity against HL-60 (Acute myeloid leukemia, AML, 72.06%), K-562 (Chronic myeloid leukemia, CML, 42.14%) and Jurkat (Acute lymphoblastic leukemia, ALL, 51.71%) cells. Myricitrin, vitexin and vanillin exhibited dose-dependent (IC-50 values 164.4, 147 & 29.22 µg/ml) and time-dependent activity with maximum cytotoxicity at 48 h. All these three compounds caused apoptosis in leukemia cells by inducing free radicals such as ROS (1.33-2.65 Arbitrary units) and NO (11.17-18.53 µM), cell membrane damage and nuclear condensation which were evidenced by increased release of LDH (1326-1439 U/L), improved lipid peroxidation (10.19-14.41 nM/mg protein) and reduced SOD level (6.2-9.21 U/mg protein) in leukemia cells. CONCLUSIONS: Based on anti-proliferative activity, the isolated phyto-compounds myrcitrin, vitexin and vanillin from M. longifolia, P. cineraria and F. indica could be developed as natural drugs for treating AML, CML and ALL leukemia types, respectively.