piperidines and Leukemia--Myeloid

The standard therapeutic approaches for acute myeloid leukemia (AML) continue to be based on anthracyclines and cytarabine. However, the prognosis for AML remains poor, especially for patients with high-risk disease. During the past decade, promising novel agents that target DNA replication and repair, as well as cell cycling and apoptosis, have been developed and are being actively investigated in AML. Among these agents is flavopiridol, which interferes with key steps of the cell cycle and effectively promotes cell death, and voreloxin, an intercalating agent that also targets topoisomerase II. Also under clinical study in AML are oligonucleotide antisense constructs, which suppress the translation of proteins essential for leukemic blast survival and proliferation, and agents that target antiapoptotic cascades. In summary, it is hoped that novel therapies such as these will augment and/or supplant our current cytarabine- and anthracycline-based approaches, overcome active drug-resistance pathways, and eventually improve outcomes for patients with AML.

Topics: Acute Disease; Anthracyclines; Antineoplastic Agents; Apoptosis; Cell Cycle; Cytarabine; Flavonoids; Humans; Leukemia, Myeloid; Piperidines

Increasing the intensity of induction chemotherapy has generated considerable recent interest in the treatment of acute myeloid leukemia. Achieving complete remission is a sine qua non condition for prolonged disease-free survival and may affect long-term outcome. In this setting, administering a repeat course of induction shortly after completion of the first course, known as timed-sequential chemotherapy (TSC), has been tested and may lead to an improved long-term outcome. Whether these results are due to the biologic recruitment of cell cycle-specific agents is unknown. However, this strategy to intensify induction may lead to more profound myelosuppression and to potential toxicities. Here we review the results of timed-sequential chemotherapy, used as induction regimen in de novo, relapsed or refractory AML or used as post-remission therapy, and compare them with those from other types of regimens.

Topics: Acute Disease; Adolescent; Adult; Animals; Antimetabolites, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Bone Marrow Diseases; Cell Cycle; Child; Cytarabine; Disease-Free Survival; Drug Administration Schedule; Drug Resistance, Neoplasm; Flavonoids; Granulocyte Colony-Stimulating Factor; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; Leukemia, Myeloid; Middle Aged; Piperidines; Premedication; Prognosis; Rats; Remission Induction; Retrospective Studies; Salvage Therapy; Treatment Outcome

The farnesyltransferase inhibitors (FTIs) are in active clinical development in a variety of human malignancies. The most promising activity to date has been demonstrated in patients with hematological malignancies, in particular acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). In patients with MDS, two non-peptidomimetic agents, tipifarnib (Zarnestra, Johnson & Johnson, New Brunswick, NJ) and lonafarnib (Sarasar, Schering-Plough, Kenilworth, NJ) have been the most extensively studied. In both phase I and phase II trials, tipifarnib has demonstrated significant efficacy with overall response rates of 30%, with complete remissions in about 15%. Dose-limiting side effects have been primarily myelosuppression, although fatigue, neurotoxicity, and occasional renal dysfunction have required dose reductions. Lonafarnib in patients with MDS has also resulted in clinical responses in approximately 30%, including significant improvements in platelet counts. Lonafarnib has been associated with primarily diarrhea and other gastrointestinal toxicity, anorexia, and nausea, which has limited its efficacy. Clinical response correlation with documentation of inhibition of farnesyltransferase and/or evidence of decreased farnesylation of downstream protein targets has not been demonstrated with either agent. In addition, the presence of an activating Ras mutation has not predicted response to therapy with FTIs in MDS and AML. Despite this, significant clinical efficacy of the FTIs in MDS, on par with that of currently available chemotherapeutic agents, has been observed, leading to further development of this new class of drugs in MDS and AML.

Topics: Acute Disease; Aged; Alkyl and Aryl Transferases; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Disease Progression; Enzyme Inhibitors; Farnesyltranstransferase; Genes, ras; Hematologic Neoplasms; Humans; Leukemia, Myeloid; Middle Aged; Myelodysplastic Syndromes; Piperidines; Protein Prenylation; Protein Processing, Post-Translational; Proto-Oncogene Proteins p21(ras); Pyridines; Quinolones; Remission Induction; Signal Transduction; Treatment Outcome

Mutations in IDH induce epigenetic and transcriptional reprogramming, differentiation bias, and susceptibility to mitochondrial inhibitors in cancer cells. Here, we first show that cell lines, PDXs, and patients with acute myeloid leukemia (AML) harboring an IDH mutation displayed an enhanced mitochondrial oxidative metabolism. Along with an increase in TCA cycle intermediates, this AML-specific metabolic behavior mechanistically occurred through the increase in electron transport chain complex I activity, mitochondrial respiration, and methylation-driven CEBPα-induced fatty acid β-oxidation of IDH1 mutant cells. While IDH1 mutant inhibitor reduced 2-HG oncometabolite and CEBPα methylation, it failed to reverse FAO and OxPHOS. These mitochondrial activities were maintained through the inhibition of Akt and enhanced activation of peroxisome proliferator-activated receptor-γ coactivator-1 PGC1α upon IDH1 mutant inhibitor. Accordingly, OxPHOS inhibitors improved anti-AML efficacy of IDH mutant inhibitors in vivo. This work provides a scientific rationale for combinatory mitochondrial-targeted therapies to treat IDH mutant AML patients, especially those unresponsive to or relapsing from IDH mutant inhibitors.

Topics: Acute Disease; Aminopyridines; Animals; Cell Line, Tumor; Doxycycline; Drug Resistance, Neoplasm; Enzyme Inhibitors; Epigenesis, Genetic; Glycine; HL-60 Cells; Humans; Isocitrate Dehydrogenase; Isoenzymes; Leukemia, Myeloid; Mice, Inbred NOD; Mice, Knockout; Mice, SCID; Mitochondria; Mutation; Oxadiazoles; Oxidative Phosphorylation; Piperidines; Pyridines; Triazines; Xenograft Model Antitumor Assays

To evaluate cellular protein changes in response to treatment with an approved drug, ibrutinib, in cells expressing normal or mutated granulocyte-colony stimulating factor receptor (G-CSFR). G-CSFR mutations are associated with some hematological malignancies. Previous studies show the efficacy of ibrutinib (a Bruton's tyrosine kinase inhibitor) in mutated G-CSFR leukemia models but do not address broader signaling mechanisms.. A label-free quantitative proteomics workflow to evaluate the cellular effects of ibrutinib treatment is established. This includes three biological replicates of normal and mutated G-CSFR expressed in a mouse progenitor cell (32D cell line) with and without ibrutinib treatment.. The proteomics dataset shows about 1000 unique proteins quantified with nearly 400 significant changes (p value < 0.05), suggesting a highly dynamic network of cellular signaling in response to ibrutinib. Importantly, the dataset is very robust with coefficients of variation for quantitation at 13.0-20.4% resulting in dramatic patterns of protein differences among the groups.. This robust dataset is available for further mining, hypothesis generation, and testing. A detailed understanding of the restructuring of the proteomics signaling cascades by ibrutinib in leukemia biology will provide new avenues to explore its use for other related malignancies.

Topics: Adenine; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Humans; Leukemia, Myeloid; Mutation; Piperidines; Proteomics; Receptors, Granulocyte Colony-Stimulating Factor; Signal Transduction

Virosecurinine is a major alkaloid of the plant Securinega suffruticosa and has been found to be a potent agent in inducing the differentiation of cancer cells. The present study aimed to investigate the antitumor effects of virosecurinine by inducing the apoptosis of leukemic K562 cells and to examine the underlying mechanisms. K562 cells were treated with different concentrations of virosecurinine (6.25, 12.5, 25, 50, 100 and 200 µmol/l) for 24, 48 and 72 h. The cell counting kit (CCK)‑8 method was used to detect the antitumor effect of K562 cells in vitro. Flow cytometry was used to observe the apoptotic ratio and analyze the cell cycle following treatment with virosecurinine in K562 cells. Light and electron microscopy was used to identify morphological alterations in the virosecurinine‑treated K562 cells. The mRNA levels of mammalian target of rapamycin (mTOR), SH2 domain‑containing inositol‑5'‑phosphatase 2 (SHIP2), phosphatase and tensin homologue (PTEN) and breakpoint cluster region (BCR)/Abelson (ABL) were detected pre and post‑virosecurinine treatment using reverse transcription quantitative polymerase chain reaction (RT‑qPCR). The generation depression effects of K562 cells cultured in vitro were detected using CCK‑8 technology, which revealed a dose and time‑dependent association. The IC50 was 32.984 µmol/l at 48 h. Flow cytometric analysis indicated that treatment with virosecurinine at concentrations of 6.25, 25 and 50 µmol/l increased the apoptotic rate of the K562 cells and caused G1/S phase arrest. RT‑qPCR indicated that virosecurinine upregulated the gene expression of PTEN and downregulated the expression of mTOR, SHIP‑2 and BCR/ABL in K562 cells. Virosecurinine inhibited the growth and proliferation of the K562 cell lines and induced apoptosis in K562 cells by affecting the expression of mTOR, SHIP2, BCR/ABL and PTEN.

Topics: Alkaloids; Antineoplastic Agents; Apoptosis; Azepines; Cell Proliferation; Cell Survival; Drug Screening Assays, Antitumor; Fusion Proteins, bcr-abl; Gene Expression; Humans; K562 Cells; Lactones; Leukemia, Myeloid; Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; Phosphoric Monoester Hydrolases; Piperidines; PTEN Phosphohydrolase; TOR Serine-Threonine Kinases

Dormant cells are characterised by low RNA synthesis. In contrast, cancer cells can be addicted to high RNA synthesis, including synthesis of survival molecules. We hypothesised that dormant cancer cells, already low in RNA, might be sensitive to apoptosis induced by RNA Polymerase II (RP2) inhibitors that further reduce RNA synthesis.. We cultured leukaemia cells continuously in vitro in the presence of an mTOR inhibitor to model dormancy. Apoptosis, damage, RNA content and reducing capacity were evaluated. We treated dormancy-enriched cells for 48 hours with the nucleoside analogues ara-C, 5-azacytidine and clofarabine, the topoisomerase targeting agents daunorubicin, etoposide and irinotecan and three multikinase inhibitors with activity against RP2 - flavopiridol, roscovitine and TG02, and we measured growth inhibition and apoptosis. We describe use of the parameter 2 × IC50 to measure residual cell targeting. RNA synthesis was measured with 5-ethynyl uridine. Drug-induced apoptosis was measured flow cytometrically in primary cells from patients with acute myeloid leukaemia using a CD34/CD71/annexinV gating strategy to identify dormant apoptotic cells.. Culture of the KG1a cell line continuously in the presence of an mTOR inhibitor induced features of dormancy including low RNA content, low metabolism and low basal ROS formation in the absence of a DNA damage response or apoptosis. All agents were more effective against the unmanipulated than the dormancy-enriched cells, emphasising the chemoresistant nature of dormant cells. However, the percentage of cell reduction by RP2 inhibitors at 2 × IC50 was significantly greater than that of other agents. RP2 inhibitors strongly inhibited RNA synthesis compared with other drugs. We also showed that RP2 inhibitors induce apoptosis in proliferating and dormancy-enriched KG1a cells and in the CD71neg CD34pos subset of primary acute myeloid leukaemia cells.. We suggest that RP2 inhibitors may be a useful class of agent for targeting dormant leukaemia cells.

Topics: Acute Disease; Adenine Nucleotides; Antineoplastic Agents; Apoptosis; Arabinonucleosides; Azacitidine; Cell Line, Tumor; Cell Survival; Clofarabine; Cytarabine; Daunorubicin; Dose-Response Relationship, Drug; Enzyme Inhibitors; Etoposide; Flavonoids; Heterocyclic Compounds, 4 or More Rings; Humans; Leukemia, Myeloid; Piperidines; Purines; RNA Polymerase II; RNA, Neoplasm; Roscovitine; Sirolimus; TOR Serine-Threonine Kinases

FK866 is a specific inhibitor of NAMPT and induces apoptosis of leukemic cells by depletion of intracellular NAD(+). Since up-regulation of NAMPT is associated with several cases of cancers, including leukemias, we asked whether in leukemic cells inhibition of NAMPT involves p53 pathway. We observed that FK866 induced apoptosis and reduced cell proliferation in NB-4, OCI-AML3 and MOLM-13 cell lines. In contrast, the leukemia cell lines, K-562 and Kasumi, containing nonfunctional p53 were relatively unaffected by FK866 treatment. Importantly, direct inhibition of sirtuins significantly reduced the viability of NB-4, OCI-AML3 and MOLM-13 cell lines. Activation of p53 by FK866 involved increased acetylation of p53 at lysine 382 with subsequent increase in the expression of p21 and BAX. Further, knockdown of p53 attenuated the effects of FK866 on apoptosis and cell cycle arrest, which was partly associated with decreased expression of p21 and BAX. Our results suggest the role of p53 acetylation pathway in the anti-leukemic effect of FK866.

Topics: Acetylation; Acrylamides; Apoptosis; bcl-2-Associated X Protein; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p21; Cytokines; Gene Knockout Techniques; Humans; Leukemia, Myeloid; NAD; Nicotinamide Phosphoribosyltransferase; Piperidines; Sirtuins; Tumor Suppressor Protein p53; Up-Regulation

Inhibitors of nicotinamide phosphoribosyltransferase have recently been validated as therapeutic targets in leukemia, but the mechanism of leukemogenic transformation downstream of this enzyme is unclear.. Here, we evaluated whether nicotinamide phosphoribosyltransferase's effects on aberrant proliferation and survival of myeloid leukemic cells are dependent on sirtuin and delineated the downstream signaling pathways operating during this process.. We identified significant upregulation of sirtuin 2 and nicotinamide phosphoribosyltransferase levels in primary acute myeloid leukemia blasts compared to in hematopoietic progenitor cells from healthy individuals. Importantly, specific inhibition of nicotinamide phosphoribosyltransferase or sirtuin 2 significantly reduced proliferation and induced apoptosis in human acute myeloid leukemia cell lines and primary blasts. Intriguingly, we found that protein kinase B/AKT could be deacetylated by nicotinamide phosphoribosyltransferase and sirtuin 2. The anti-leukemic effects of the inhibition of nicotinamide phosphoribosyltransferase or sirtuin 2 were accompanied by acetylation of protein kinase B/AKT with subsequent inhibition by dephosphorylation. This leads to activation of glycogen synthase kinase-3 β via diminished phosphorylation and, ultimately, inactivation of β-catenin by phosphorylation.. Our results provide strong evidence that nicotinamide phosphoribosyltransferase and sirtuin 2 participate in the aberrant proliferation and survival of leukemic cells, and suggest that the protein kinase B/AKT/ glycogen synthase kinase-3 β/β-catenin pathway is a target for inhibition of nicotinamide phosphoribosyltransferase or sirtuin 2 and, thereby, leukemia cell proliferation.

Topics: Acrylamides; Apoptosis; Benzothiazoles; beta Catenin; Blast Crisis; Cell Line, Tumor; Cell Proliferation; Cell Survival; Enzyme Activation; Enzyme Inhibitors; Gene Expression Regulation, Leukemic; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Humans; Leukemia, Myeloid; Models, Biological; Nicotinamide Phosphoribosyltransferase; Piperidines; Proto-Oncogene Proteins c-akt; RNA, Messenger; Signal Transduction; Sirtuin 2

Modulation of protein kinase C (PKC) activity has been demonstrated to either prevent or enhance drug-induced apoptosis in various tissue types. We tested four novel modulators of PKC activity in comparison to the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) for the capability to affect differentiation, cell cycle progression and apoptosis in the human myeloid leukemia cell lines U937 and HL-60. Farnesyl thiotriazole (FTT) and N-(n-heptyl)-5-chloro-1-naphthalenesulfonamide (SC-10) are both direct activators of PKC, whereas 6-(2-(4-[(4-fluorophe-nyl)phenylmethylene]-1-piperidinyl)ethyl)-7-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one (R59022) and [3-[2-[4-(bis-(4-fluorophenyl)methylene]piperidin-1-yl)ethyl]-2,3-dihydro-2-thioxo-4(1H)-quin-azolinone (R59949) are diacyl glycerol kinase inhibitors that activate PKC by enhancing the levels of the endogenous ligand diacyl glycerol. U937 cells displayed a slight reduction in the number of cells in G(2)/M cell cycle phase after exposure to FTT, SC-10, R59022 and R59949, respectively. In contrast, HL-60 cells demonstrated a largely unaltered cell cycle distribution. Whereas TPA treatment resulted in a strong induction of p21(WAF/CIP1), c-Fos and c-Jun levels, neither one of the novel PKC activators altered expression of these proteins. Consequently, we tested the ability of the activators to cause membrane translocation of PKC. While TPA treatment resulted in translocation of the PKC isoforms alpha, delta and epsilon, SC-10 and FTT failed to induce alterations in the PKC content of the membrane and cytosolic fractions, respectively. Expression of the beta(2)-integrin CD11c that is induced during TPA-mediated differentiation remained unaltered after exposure to SC-10 and was partly reduced after treatment with FTT. To further investigate the effect of these activators upon apoptosis in leukemic cells, HL-60 and U937 cells were treated with 1-beta-D-arabinofuranosylcytosine (Ara-C) or etoposide (VP-16). Whereas TPA strongly reduced apoptosis in Ara-C- or VP-16-treated U937 cells, little if any reduction was observed after pretreatment with either FTT, SC-10, R59022 or R59949, respectively, in these cells. In contrast, TPA enhanced apoptosis in Ara-C- or VP-16-treated HL-60 cells. Interestingly, FTT and SC-10 demonstrated a protective effect in Ara-C-treated HL-60 cells. Taken together, these data suggest that the novel PKC activators FTT, SC-10, R59022 and R59949 exhibit modest biological effects upon leukemi

Topics: Antineoplastic Agents; Apoptosis; CD11c Antigen; CD4 Antigens; Cell Cycle; Cell Differentiation; Diacylglycerol Kinase; Enzyme Activators; Enzyme Inhibitors; Farnesol; Flow Cytometry; Genes, fos; Genes, jun; Humans; Immunoblotting; Isoenzymes; Leukemia, Myeloid; Naphthalenes; Oncogene Protein p21(ras); Piperidines; Protein Kinase C; Pyrimidinones; Quinazolines; Quinazolinones; Sulfonamides; Thiazoles; Triazoles; Tumor Cells, Cultured

Previous studies have shown that coexposure to marginally toxic concentrations of phorbol 12-myristate 13-acetate (PMA; 10 nM) and the cyclin-dependent kinase inhibitor flavopiridol (FP; 100-200 nM) synergistically induces apoptosis in human myeloid leukemia cells U937 and HL-60 (i.e., >50% apoptotic at 24 h). Attempts have now been made to characterize the cell death pathway(s) involved in this phenomenon. In contrast to cytochrome c release and caspase-3 activation, which occur within 2.5 h of PMA/FP coexposure, caspase-8 activation and Bid cleavage appeared as later events. Such findings implicate the mitochondria-dependent pathway in the initial induction of apoptosis by PMA/FP. However, U937 cells ectopically expressing CrmA, dominant-negative caspase-8, or dominant-negative Fas-associated death domain that were highly resistant to tumor necrosis factor (TNF)/cycloheximide-induced lethality displayed significant, albeit incomplete, resistance to PMA/FP-induced apoptosis after 24 h. Furthermore, coadministration of TNF soluble receptor significantly attenuated PMA/FP-induced apoptosis in U937 (p < 0.02) and HL-60 (p < 0.03) cells at 24 h. PMA/FP coadministration also triggered substantial increases in TNFalpha mRNA and protein secretion compared with the effects of PMA administered alone. The protein kinase C (PKC) inhibitor bisindolylmaleimide (1 microM) completely blocked PMA/FP-induced TNFalpha secretion in U937 cells and attenuated apoptosis. Taken together, these results suggest that coadministration of PMA with FP in myeloid leukemia cells initially triggers mitochondrial damage, an event followed by the PKC-dependent induction and release of TNFalpha, supporting a model in which the synergistic induction of leukemic cell apoptosis by this drug combination proceeds via both mitochondrial- and TNF receptor-related apoptotic pathways.

Topics: Antineoplastic Agents; Apoptosis; Arabidopsis Proteins; Carcinogens; Caspase 8; Caspase 9; Caspases; Drug Synergism; Enzyme Precursors; Fatty Acid Desaturases; Flavonoids; Humans; Leukemia, Myeloid; Mitochondria; Piperidines; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha; U937 Cells

CP-46,665-1, an antineoplastic lipoidal amine, was found to inhibit phospholipid/Ca2+-dependent protein kinase (PL/Ca-PK, or protein kinase C), with an IC50 (concentration causing a 50% inhibition) of 10 microM. Its inhibition of the enzyme was reversed by phosphatidylserine, but not by Ca2+. The agent also inhibited the enzyme activity which was further augmented by 12-0-tetradecanoylphorbol-13-acetate (TPA), mezerein or diolein. Phosphorylation of endogenous proteins from HL-60 cells by the enzyme, with or without being further augmented by TPA, was inhibited by CP-46,665-1 as well as by alkyllysophospholipid (an antineoplastic agent). CP-46,665-1, while without effect on cyclic AMP-dependent protein kinase, also inhibited myosin light chain kinase (a calmodulin/Ca2+-dependent protein kinase). The present findings suggest that inhibition of the Ca2+-effector enzymes may be related in part to the antimetastatic activity of the lipoidal amine.

Topics: Animals; Antineoplastic Agents; Carcinogens; Cattle; Enzyme Activation; Humans; In Vitro Techniques; Leukemia, Myeloid; Neoplasm Proteins; Phosphorylation; Piperidines; Protein Kinase C; Protein Kinase Inhibitors; Protein Kinases; Rabbits; Swine