Modulation of DNA methylation by a sesquiterpene lactone parthenolide.

Hypermethylation of 5'-cytosine-guanosine islands of tumor suppressor genes resulting in their silencing has been proposed to be a hallmark of various tumors. Modulation of DNA methylation with DNA methylation inhibitors has been shown to result in cancer cell differentiation or apoptosis and represents a novel strategy for chemotherapy. Currently, effective DNA methylation inhibitors are mainly limited to decitabine and 5-azacytidine, which still show unfavorable toxicity profiles in the clinical setting.

Transferrin receptor-targeted lipid nanoparticles for delivery of an antisense oligodeoxyribonucleotide against Bcl-2.

Antisense oligonucleotide G3139-mediated down-regulation of Bcl-2 is a potential strategy for overcoming chemoresistance in leukemia. However, the limited efficacy shown in recent clinical trials calls attention to the need for further development of novel and more efficient delivery systems. In order to address this issue, transferrin receptor (TfR)-targeted, protamine-containing lipid nanoparticles (Tf-LNs) were synthesized as delivery vehicles for G3139.

Sodium channel activity modulates multiple functions in microglia.

Microglia provide surveillance in the central nervous system and become activated following tissue insult. Detailed mechanisms by which microglia detect and respond to their environment are not fully understood, but it is known that microglia express a number of surface receptors and ion channels, including voltage-gated sodium channels, that participate in transduction of external stimuli to intra-cellular responses. To determine whether activated microglia are affected by the activity of sodium channels, we examined the expression of sodium channel isoforms in cultured microglia and the action of sodium channel blockade on multiple functions of activated microglia.

Curcumin is a potent DNA hypomethylation agent.

Molecular docking of the interaction of curcumin and DNMT1 suggested that curcumin covalently blocks the catalytic thiolate of C1226 of DNMT1 to exert its inhibitory effect. This was validated by showing that curcumin inhibits the activity of M. SssI with an IC(50) of 30 nM, but no inhibitory activity of hexahydrocurcumin up to 100 microM.

Antitumor activity of G3139 lipid nanoparticles (LNPs).

G3139, an antisense oligodeoxyribonucleotide (ODN) against Bcl-2, contains two CpG dinucleotides and has shown immunostimulatory activities in preclinical studies. It has been suggested that immunoactivation, rather than antisense activity, is primarily responsible for the therapeutic efficacy of G3139. Nanoparticle formulations naturally target phagocytic antigen presenting cells and therefore might enhance the immunological effects of G3139.

Isolation and characterization of a gene encoding cinnamate 4-hydroxylase from Parthenocissus henryana.

Cinnamate 4-hydroxylase (C4H, EC 1.14.13.

The Mll partial tandem duplication: differential, tissue-specific activity in the presence or absence of the wild-type allele.

The partial tandem duplication of MLL (MLL-PTD) is found in 5% to 10% of patients with acute myeloid leukemia (AML) and normal cytogenetics. Its expression in leukemic blasts is coincident with a silenced wild-type (WT) MLL allele. We therefore generated mice expressing the Mll-PTD in the absence of Mll-WT.

DNA hypermethylation and epigenetic silencing of the tumor suppressor gene, SLC5A8, in acute myeloid leukemia with the MLL partial tandem duplication.

Posttranslationally modified histones and DNA hypermethylation frequently interplay to deregulate gene expression in cancer. We report that acute myeloid leukemia (AML) with an aberrant histone methyltransferase, the mixed lineage leukemia partial tandem duplication (MLL-PTD), exhibits increased global DNA methylation versus AML with MLL-wildtype (MLL-WT; P = .02).

Phase I study of GTI-2040, an antisense to ribonucleotide reductase, in combination with high-dose cytarabine in patients with acute myeloid leukemia.

Purpose: Inhibition of ribonucleotide reductase reduces the availability of the endogenous pool of deoxycytidine and may increase cytarabine (AraC) cytotoxicity. We performed a phase I dose escalation trial of AraC combined with GTI-2040, a 20-mer antisense oligonucleotide shown in preclinical studies to decrease levels of the R2 subunit of ribonucleotide reductase, to determine the maximum tolerated dose in adults with relapsed/refractory acute myeloid leukemia.

Experimental Design: Twenty-three adults (ages 18-59 years) were enrolled in this dose escalation phase I trial, receiving high-dose AraC twice daily combined with infusional GTI-2040.

A phase I biological study of MG98, an oligodeoxynucleotide antisense to DNA methyltransferase 1, in patients with high-risk myelodysplasia and acute myeloid leukemia.

Purpose: Epigenetic silencing via aberrant promoter DNA hypermethylation of normal genes has been described as a leukemogenic mechanism in myelodysplastic syndromes (MDS) and acute myeloid leukemias (AML). We hypothesized that MG98, an oligonucleotide antisense to DNA methyltransferase 1 (DNMT1), could reverse malignant phenotypes by down-regulating DNMT1 and inducing reexpression of hypermethylated genes. This phase I study was conducted to determine a biologically effective dose and describe the safety of MG98 in MDS/AML.

Bortezomib induces DNA hypomethylation and silenced gene transcription by interfering with Sp1/NF-kappaB-dependent DNA methyltransferase activity in acute myeloid leukemia.

Bortezomib reversibly inhibits 26S proteasomal degradation, interferes with NF-kappaB, and exhibits antitumor activity in human malignancies. Zinc finger protein Sp1 transactivates DNMT1 gene in mice and is functionally regulated through protein abundance, posttranslational modifications (ie, ubiquitination), or interaction with other transcription factors (ie, NF-kappaB). We hypothesize that inhibition of proteasomal degradation and Sp1/NF-kappaB-mediated transactivation may impair aberrant DNA methyltransferase activity.

MicroRNA-29 family reverts aberrant methylation in lung cancer by targeting DNA methyltransferases 3A and 3B.

MicroRNAs (miRNAs) are small, noncoding RNAs that regulate expression of many genes. Recent studies suggest roles of miRNAs in carcinogenesis. We and others have shown that expression profiles of miRNAs are different in lung cancer vs.

FTY720, a new alternative for treating blast crisis chronic myelogenous leukemia and Philadelphia chromosome-positive acute lymphocytic leukemia.

Blast crisis chronic myelogenous leukemia (CML-BC) and Philadelphia chromosome-positive (Ph1-positive) acute lymphocytic leukemia (ALL) are 2 fatal BCR/ABL-driven leukemias against which Abl kinase inhibitors fail to induce a long-term response. We recently reported that functional loss of protein phosphatase 2A (PP2A) activity is important for CML blastic transformation. We assessed the therapeutic potential of the PP2A activator FTY720 (2-amino-2-[2-(4-octylphenyl)ethyl]-1,3-propanediol hydrochloride), an immunomodulator in Phase III trials for patients with multiple sclerosis or undergoing organ transplantation, in CML-BC and Ph1 ALL patient cells and in in vitro and in vivo models of these BCR/ABL+ leukemias.

Role of formulation composition in folate receptor-targeted liposomal doxorubicin delivery to acute myelogenous leukemia cells.

Targeted drug delivery has the potential to improve the efficacy of a therapeutic agent while reducing its side effects. The folate receptor type beta (FR-beta) is a cell surface marker selectively expressed in the leukemic cells of approximately 70% of acute myeloid leukemia (AML) patients. Upregulation of FR-beta may also be selectively induced in AML cells by treatment with all-trans-retinoic acid (ATRA).

Transcriptional control of human T-BET expression: the role of Sp1.

Murine T-bet (T-box expressed in T cells) is a master regulator of IFN-gamma gene expression in NK and T cells. T-bet also plays a critical role in autoimmunity, asthma and other diseases. However, cis elements or trans factors responsible for regulating T-bet expression remain largely unknown.

Phase I study of decitabine alone or in combination with valproic acid in acute myeloid leukemia.

Purpose: To determine an optimal biologic dose (OBD) of decitabine as a single agent and then the maximum-tolerated dose (MTD) of valproic acid (VA) combined with decitabine in acute myeloid leukemia (AML).

Patients And Methods: Twenty-five patients (median age, 70 years) were enrolled; 12 were untreated and 13 had relapsed AML. To determine an OBD (based on a gene re-expression end point), 14 patients received decitabine alone for 10 days.

Exacerbation of experimental autoimmune encephalomyelitis after withdrawal of phenytoin and carbamazepine.

Objective: In vitro observations and studies in murine experimental autoimmune encephalomyelitis (EAE) have shown protective effects of sodium channel blockers on central nervous system axons and improved clinical status when treatment is continued throughout the period of observation. Several clinical studies of sodium channel blockers are under way in patients with multiple sclerosis. Here we asked whether a protective effect would persist after withdrawal of a sodium channel blocker.

Targeting AML1/ETO-histone deacetylase repressor complex: a novel mechanism for valproic acid-mediated gene expression and cellular differentiation in AML1/ETO-positive acute myeloid leukemia cells.

In t(8;21) acute myeloid leukemia (AML), the AML1/ETO fusion protein promotes leukemogenesis by recruiting class I histone deacetylase (HDAC)-containing repressor complex to the promoter of AML1 target genes. Valproic acid (VPA), a commonly used antiseizure and mood stabilizer drug, has been shown to cause growth arrest and induce differentiation of malignant cells via HDAC inhibition. VPA causes selective proteasomal degradation of HDAC2 but not other class I HDACs (i.

Characterization of in vitro and in vivo hypomethylating effects of decitabine in acute myeloid leukemia by a rapid, specific and sensitive LC-MS/MS method.

DNA hypermethylation is a common finding in malignant cells and has been explored as a therapeutic target for hypomethylating agents (e.g., decitabine).

Histone H4 N-terminal acetylation in Kasumi-1 cells treated with depsipeptide determined by acetic acid-urea polyacrylamide gel electrophoresis, amino acid coded mass tagging, and mass spectrometry.

Disrupted patterns of acetylation and deacetylation of core histones play an important role in silencing transcription of hematopoietic important genes in acute myeloid leukemia (AML). A thorough investigation of these mechanisms and the response to pharmacologic modifiers will provide a better understanding of the role of histone acetylation in leukemogenesis. We describe here an analytical approach that combines acid urea polyacrylamide gel electrophoresis (AU-PAGE), amino acid coded mass tagging (AACM), and mass spectrometry (MS) for the investigation of histone acetylation patterns.

Simultaneous metabolic labeling of cells with multiple amino acids: Localization and dynamics of histone acetylation and methylation.

Simultaneous metabolic labeling of cells with multiple amino acids combined with acetic acid urea-PAGE and MS was used to characterize histones in Kasumi-1 cells treated with the histone deacetylase inhibitor depsipeptide (DDP). The approach allowed for rapid targeting, identification, and subsequent characterization of peptides containing sites of acetylation or methylation. Multiple methylation sites were determined for histone H3 including: di- and tri-methylation of K9 and K27; mono- and di-methylation of K36 and K79; and mono-methylation of K37.

5-Aza-2'-deoxycytidine and depsipeptide synergistically induce expression of BIK (BCL2-interacting killer).

DNA methylation and histone acetylation are main epigenetic events regulating gene expression, serving as anticancer drug targets. A combination of the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine with the histone deacetylase inhibitor depsipeptide synergistically induces apoptosis. To characterize genes involved in this process, we measured expression of 376 apoptosis-related genes with microarrays after treatment with the two inhibitors alone or in combination.

High content of resveratrol in lettuce transformed with a stilbene synthase gene of Parthenocissus henryana.

Resveratrol (trans-3,5,4'-trihydroxystilbene) is a plant phytoalexin which has positive effects on human health. Stilbene synthase (STS) is a key enzyme involved in resveratrol biosynthesis. To construct a vector for STS expression in lettuce plant, a cDNA-encoding STS of Parthenocissus henryana was fused to the Cauliflower mosaic virus (CaMV) 35S promoter, and the bar gene was used as a selective marker gene.

Mll partial tandem duplication induces aberrant Hox expression in vivo via specific epigenetic alterations.

We previously identified a rearrangement of mixed-lineage leukemia (MLL) gene (also known as ALL-1, HRX, and HTRX1), consisting of an in-frame partial tandem duplication (PTD) of exons 5 through 11 in the absence of a partner gene, occurring in approximately 4%-7% of patients with acute myeloid leukemia (AML) and normal cytogenetics, and associated with a poor prognosis. The mechanism by which the MLL PTD contributes to aberrant hematopoiesis and/or leukemia is unknown. To examine this, we generated a mouse knockin model in which exons 5 through 11 of the murine Mll gene were targeted to intron 4 of the endogenous Mll locus.

Long-term protection of central axons with phenytoin in monophasic and chronic-relapsing EAE.

Axonal degeneration is a major contributor to non-remitting deficits in multiple sclerosis, and there is thus considerable current interest in the development of strategies that might prevent axonal loss in neuroinflammatory disease. Dysregulation of sodium ion homeostasis has been implicated in mechanisms leading to axonal degeneration, and several studies have shown that blockade of sodium channels can ameliorate axon damage following anoxic, traumatic and nitric oxide-induced CNS injury. Two sodium channel blockers, phenytoin and flecainide, have been reported to protect axons in experimental autoimmune encephalomyelitis (EAE) for 30 days, but long-term protective effects have not been studied.