Novel small molecule SIRT2 inhibitors induce cell death in leukemic cell lines

Abstract Δ9-Tetrahydrocannabinol (THC) is the active metabolite of cannabis. THC causes cell death in vitro through the activation of complex signal transduction pathways. However, the role that the cannabinoid 1 and 2 receptors (CB1-R and CB2-R) play in this process is less clear. We therefore investigated the role of the CB-Rs in mediating apoptosis in 3 leukemic cell lines and performed microarray and immunoblot analyses to establish further the mechanism of cell death. We developed a novel flow cytometric technique of measuring the expression of functional receptors and used combinations of selective CB1-R and CB2-R antagonists and agonists to determine their individual roles in this process. We have shown that THC is a potent inducer of apoptosis, even at 1 × IC50 (inhibitory concentration 50%) concentrations and as early as 6 hours after exposure to the drug. These effects were seen in leukemic cell lines (CEM, HEL-92, and HL60) as well as in peripheral blood mononuclear cells. Additionally, THC did not appear to act synergistically with cytotoxic agents such as cisplatin. One of the most intriguing findings was that THC-induced cell death was preceded by significant changes in the expression of genes involved in the mitogen-activated protein kinase (MAPK) signal transduction pathways. Both apoptosis and gene expression changes were altered independent of p53 and the CB-Rs.

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Synthesis of Two Novel Homologous Polyphosphoesters Containing Aminophosphonate Units and Cytotoxicity of Some Low-Molecular and Polymeric Aminophosphonate Derivatives

Advances in Materials Science and Engineering ◽

10.1155/2018/9565401 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8

Author(s):

Ivanka Kraicheva ◽

Georgi Momekov ◽

Rositsa Mihaylova ◽

Margarita Topashka-Ancheva ◽

Ivelina Tsacheva ◽

...

Keyword(s):

Cell Death ◽

Cell Lines ◽

Leukemic Cell ◽

The Novel ◽

Histological Subtype ◽

New Materials ◽

Antitumor Effects ◽

Cytotoxicity Assays ◽

Leukemic Cell Lines

Two novel polyphosphoesters containing anthracene- and furan-derived aminophosphonate moieties, namely, poly[oxyethylene(aminophosphonate-co-H-phosphonate)]s P-12 and P-13, were synthesized through an addition of poly(oxyethylene H-phosphonate) to 9-anthrylidene-furfurylamine and characterized. The novel polyphosphoester P-12 and a series of previously described anthracene-derived compounds including Schiff bases S-1 and S-2, α-aminophosphonates A-3–A-6, bis-aminophosphonate B-6, two enantiomers A-5a and A-5b, and polyphosphoesters P-8–P-11 containing aminophosphonate units were screened for antitumor activity against a panel of human leukemic cell lines, using cisplatin as a reference cytotoxic agent. As concluded from the cytotoxicity assays, both precursors S-1 and S-2 presented similar cytotoxicity profiles that are cisplatin-like only in the REH cell line. Leader compound of the α-aminophosphonates is A-4 with cell death-inducing properties fully equaling those of the referent drug in all of the screened leukemic cell lines with the only exception being the AML histological subtype HL-60. Some of the polymeric analogues elicited moderate (P-10 and P-12) to low (P-11) cytotoxic activity, whereas the polyphosphoesters P-8 and P-9 produced in vitro antitumor effects largely surpassing cisplatin’s. The compounds P-8, P-9, and A-4 could be potential new materials for anticancer therapeutic purposed.

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Induction of apoptotic cell death by direct-current treatment in human leukemic cell lines

Journal of Cancer Research and Clinical Oncology ◽

10.1007/s004320050073 ◽

1997 ◽

Vol 123 (7) ◽

pp. 370-376 ◽

Cited By ~ 2

Author(s):

Masatsugu Kurokawa ◽

Hiroshi Sakagami ◽

Fumio Kokubu ◽

Hiromichi Noda ◽

Minoru Takeda ◽

...

Keyword(s):

Cell Death ◽

Cell Lines ◽

Direct Current ◽

Apoptotic Cell ◽

Leukemic Cell ◽

Current Treatment ◽

Apoptotic Cell Death ◽

Human Leukemic Cell ◽

Leukemic Cell Lines

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Induction of apoptotic cell death by direct-current treatment in human leukemic cell lines

Journal of Cancer Research and Clinical Oncology ◽

10.1007/bf01240119 ◽

1997 ◽

Vol 123 (7) ◽

pp. 370-376 ◽

Cited By ~ 4

Author(s):

Masatsugu Kurokawa ◽

Hiroshi Sakagami ◽

Fumio Kokubu ◽

Hiromichi Noda ◽

Minoru Takeda ◽

...

Keyword(s):

Cell Death ◽

Cell Lines ◽

Direct Current ◽

Apoptotic Cell ◽

Leukemic Cell ◽

Current Treatment ◽

Apoptotic Cell Death ◽

Human Leukemic Cell ◽

Leukemic Cell Lines

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Chemotherapy Exposure Decreases Leukemia Cell Deformability as Determined by Atomic Force Microscopy: Implications for Leukostasis in Acute Leukemia.

Blood ◽

10.1182/blood.v108.11.2359.2359 ◽

2006 ◽

Vol 108 (11) ◽

pp. 2359-2359 ◽

Cited By ~ 1

Author(s):

Wilbur A. Lam ◽

Michael J. Rosenbluth ◽

Daniel A. Fletcher

Keyword(s):

Cell Death ◽

Cell Lines ◽

Standard Error ◽

Leukemic Cell ◽

Leukemic Cells ◽

Cell Stiffness ◽

Leukemia Cells ◽

Leukemic Cell Lines ◽

Apparent Stiffness ◽

Error Bars

Abstract Leukostasis, a life-threatening complication of acute leukemia, occurs when leukemia cells obstruct the circulation of vital organs like the brain and lungs leading to intracranial hemorrhage or respiratory failure. Although the pathophysiology of leukostasis is poorly understood, an elevated concentration of circulating leukemia cells, pathologic adhesion, and decreased cell deformability are thought to play significant roles. Clinical deterioration can occur soon after chemotherapy is initiated, suggesting that chemotherapy itself may be a risk factor for leukostasis. To investigate the effects of chemotherapy on cell stiffness, we performed serial single cell deformability measurements with an atomic force microscope (AFM), a commonly used tool in nanoscience for imaging and characterizing mechanical properties of materials on a submicron level, and modified the AFM to operate in cell culture conditions at 37°C. Leukemia cells from patients with acute lymphoblastic leukemia and acute myeloid leukemia as well as leukemia cell lines were incubated with chemotherapeutic agents, and changes in cell stiffness were tracked over time with AFM as the cells underwent chemotherapy-induced cell death. In the presence of dexamethasone or daunorubicin, leukemia cells exhibited increases in stiffness by as much as two orders of magnitude. Cell stiffness appeared to increase before caspase activation and peaked after completion of cell death, and the rate at which cell stiffness increased was dependent on chemotherapy type. Stiffening with cell death was found to occur for all cell types and chemotherapies investigated and is due, at least in part, to dynamic changes in the actin cytoskeleton. This observed correlation between cell death and cell stiffening may partially explain why some leukemia patients develop leukostasis shortly after starting chemotherapy, and it suggests that leukocytoreduction should remain an important treatment for hyperleukocytosis in acute leukemia. Figure 1. Average apparent stiffness of dead (dark gray) leukemic cells exposed to chemotherapy is significantly higher compared to untreated (light gray) cells (n > 15, p < 0.05 for all comparisons of dead/untreated populations). (A) Primary ALL cells and lymphoid leukemic cell lines exposed to 1 μM dexamethasone (B) Primary AML and myeloid leukemic cell lines exposed to 1μM daunorubicin. Error bars are standard error. Figure 1. Average apparent stiffness of dead (dark gray) leukemic cells exposed to chemotherapy is significantly higher compared to untreated (light gray) cells (n > 15, p < 0.05 for all comparisons of dead/untreated populations). (A) Primary ALL cells and lymphoid leukemic cell lines exposed to 1 μM dexamethasone (B) Primary AML and myeloid leukemic cell lines exposed to 1μM daunorubicin. Error bars are standard error. Figure 2. Apparent stiffness of leukemic cells increases with progression of cell death. (A) A typical stiffness trace of a single M5 AML cell exposed to 1μM daunorubicin (circles). The apparent stiffness of a typical control cell remains relatively constant (triangles) and does not undergo apoptosis or cell death during the course of the experiment. Transition from open to filled shapres represents onset of cell death. Early apoptosis is defined as caspase 3 or 7 postivie staining and late apoptosis/dead is defined as Sytox Green (marker for cell membrane integrity loss) positive staining. (B) From the same patient sample, the average apparent stiffness of a population of late apoptotic/dead AML cells was significantly stiffer than early apoptopic cells and controls (n = 15, p< 0.05). Error bars are standard error. Figure 2. Apparent stiffness of leukemic cells increases with progression of cell death. (A) A typical stiffness trace of a single M5 AML cell exposed to 1μM daunorubicin (circles). The apparent stiffness of a typical control cell remains relatively constant (triangles) and does not undergo apoptosis or cell death during the course of the experiment. Transition from open to filled shapres represents onset of cell death. Early apoptosis is defined as caspase 3 or 7 postivie staining and late apoptosis/dead is defined as Sytox Green (marker for cell membrane integrity loss) positive staining. (B) From the same patient sample, the average apparent stiffness of a population of late apoptotic/dead AML cells was significantly stiffer than early apoptopic cells and controls (n = 15, p< 0.05). Error bars are standard error.

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Induction of Apoptosis and Autophagy By Nampt Inhibition in Adult T-Cell Leukemia/Lymphoma and Leukemic Cell Lines

Blood ◽

10.1182/blood.v128.22.2327.2327 ◽

2016 ◽

Vol 128 (22) ◽

pp. 2327-2327

Author(s):

Tomohiro Kozako ◽

Makoto Yoshimitsu ◽

Naomichi Arima ◽

Keisuke Sato ◽

Moe Toyoshima ◽

...

Keyword(s):

Cell Death ◽

T Cell ◽

Cell Lines ◽

Cell Lymphoma ◽

Leukemic Cell ◽

T Cell Leukemia ◽

Cell Leukemia ◽

Adult T Cell Leukemia ◽

Protein Levels ◽

Leukemic Cell Lines

Abstract Introduction: Adult T-cell leukemia/lymphoma (ATL) is an aggressive peripheral T-cell neoplasm that develops after long-term infection with human T-cell leukemia virus type I (HTLV-1). Despite the recent advances in chemotherapy, allogeneic hematopoietic stem cell transplantation, and supportive care, the prognosis for patients with acute, lymphoma, or unfavorable chronic subtypes is one of the poorest among hematological malignancies. The identification of new molecular targets for ATL prevention and treatment is desired. SIRT1, a nicotinamide adenine dinucleotide (NAD+)-dependent histone/protein deacetylase, plays crucial roles in various physiological processes, including aging and apoptosis. We previously reported that ATL patients had significantly higher SIRT1 protein levels and novel small-molecule SIRT1 inhibitors are highly effective against ATL cells.1,2 Nicotinamide phosphoribosyltransferase (Nampt) also known as pre-B-cell colony-enhancing factor 1 or visfatin is a rate-limiting enzyme in NAD+ biosynthesis, and it regulates intracellular ATP levels in mammalian cells. Most cancer cells (acute myeloid leukemia [AML], acute lymphoblastic leukemia [ALL], mantle cell lymphoma [MCL], chronic lymphocytic leukemia [CLL], and T-cell lymphoma) is sensitive to low concentrations of FK866, Nampt inhibitor, as measured in cytotoxicity and clonogenic assays.3Here, we assessed how Nampt is regulated in ATL cells and leukemic cell lines. Results: We observed that ATL patients had significantly higher SIRT1 and Nampt protein levels than healthy controls. FK866 induced significant growth inhibition and apoptosis (Annexin V+ cells and TUNEL) in leukemia/lymphoma cell lines (HTLV-1-related cell lines: S1T, MT-2; Jurkat and HL60). FK866 showed potent activities with GI50values of 0.63, 3.7, 1.0, and 3,4 nM for S1T, MT-2, Jurkat, and HL60 cells, respectively. FK866 also activated caspase activity (caspase-3, 8, and 9) with DNA fragmentation. However, a caspase inhibitor did not inhibit this caspase-dependent cell death. Interestingly, FK866 increased the LC3-II-enriched protein fraction, indicating autophagosome accumulation as well as autophagy. Autophagy detection was also performed using the CytoID Autophagy detection kit. Autophagy levels are increased in the presence of STF-62247 pre-treated with bafilomycin A1, a specific inhibitor of vacuolar proton ATPase, whose inhibition is known to block the fusion of autophagosomes with lysosomes for 2 h. Thus, FK866 simultaneously caused apoptosis and autophagy. Conclusion:These results suggest that Nampt inhibitor is highly effective against ATL cells in caspase-dependent or -independent manners with autophagy, and that its clinical application might improve the prognosis of patients with this fatal disease. 1. Kozako T, Aikawa A, Shoji T, et al. High expression of the longevity gene product SIRT1 and apoptosis induction by sirtinol in adult T-cell leukemia cells. Int J Cancer. 2012;131:2044-2055. 2. Kozako T, Suzuki T, Yoshimitsu M, et al. Novel small-molecule SIRT1 inhibitors induce cell death in adult T-cell leukaemia cells. Sci Rep. 2015;5:11345. 3. Nahimana A, Attinger A, Aubry D, et al. The NAD biosynthesis inhibitor APO866 has potent antitumor activity against hematologic malignancies. Blood. 2009;113:3276-3286. Disclosures Yoshimitsu: HUYA Bioscience International: Research Funding.

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Greensporone A, a Fungal Secondary Metabolite Suppressed Constitutively Activated AKT via ROS Generation and Induced Apoptosis in Leukemic Cell Lines

Biomolecules ◽

10.3390/biom9040126 ◽

2019 ◽

Vol 9 (4) ◽

pp. 126 ◽

Cited By ~ 1

Author(s):

Kirti Prabhu ◽

Kodappully Siveen ◽

Shilpa Kuttikrishnan ◽

Anh Jochebeth ◽

Tayyiba Ali ◽

...

Keyword(s):

Cell Death ◽

Cytochrome C ◽

Cell Lines ◽

Apoptotic Cell ◽

Leukemic Cell ◽

Apoptotic Cell Death ◽

Leukemic Cells ◽

Leukemic Cell Lines ◽

Fungal Secondary Metabolite

Greensporone A is a fungal secondary metabolite that has exhibited potential in vitro for anti-proliferative activity in vitro. We studied the anticancer activity of greensporone A in a panel of leukemic cell lines. Greensporone A-mediated inhibition of proliferation is found to be associated with the induction of apoptotic cell death. Greensporone A treatment of leukemic cells causes inactivation of constitutively activated AKT and its downstream targets, including members GSK3 and FOXO1, and causes downregulation of antiapoptotic genes such as Inhibitor of Apoptosis (IAPs) and Bcl-2. Furthermore, Bax, a proapoptotic member of the Bcl-2 family, was found to be upregulated in leukemic cell lines treated with greensporone A. Interestingly, gene silencing of AKT using AKT specific siRNA suppressed the expression of Bcl-2 with enhanced expression of Bax. Greensporone A-mediated increase in Bax/Bcl-2 ratio causes permeabilization of the mitochondrial membrane leading to the accumulation of cytochrome c in the cytoplasm. Greensporone A-induced cytochrome c accumulation causes the activation of caspase cascade and cleavage of its effector, poly(ADP-ribose) polymerase (PARP), leading to apoptosis. Greensporone A-mediated apoptosis in leukemic cells occurs through the generation of reactive oxygen species (ROS) due to depletion of glutathione (GSH) levels. Finally, greensporone A potentiated the anticancer activity of imatinib in leukemic cells. In summary, our study showed that greensporone A suppressed the growth of leukemic cells via induction of apoptotic cell death. The apoptotic cell death occurs by inhibition of AKT signaling and activation of the intrinsic apoptotic/caspase pathways. These results raise the possibility that greensporone A could be developed as a therapeutic agent for the treatment of leukemia and other hematological malignancies.

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