Estrogen down-regulates nicotine-induced adhesion molecule expression via nongenomic signal pathway in endothelial cells

Although gonadal hormone mostly causes genotropic actions through the members of nuclear receptor family, it also can regulate these actions via membrane receptor. To explore the possibility of plasma membrane estrogen receptors (mER) mediating genotropic events, we have investigated estrogen's effect on nicotine-stimulated adhesion molecule expression and evaluated whether this effect depends on calcium, MAPK signal pathway. Fluorescence Spectroscopy analysis of Ca2+ from human umbilical vein endothelial cells (HUVECs) showed through mER, estrogen induced a rapid rise of intracellular free Ca2+ concentration and this rise could not be inhibited by tamoxifen (classic ER inhibitor). In the context of nicotine stimulating, however, estrogen attenuated phosphorylation of mitogen-activated protein kinase (MAPK) family members, extracellular signal regulated kinase 1/2 (ERK1/2), p38 but not c-Jun-N-terminal kinase (JNK) in HUVECs and this effect could not still be prevented by tamoxifen. In the meantime, estrogen also down-regulated surface/soluble vascular cell adhesion molecule (VCAM-1, sVCAM-1) and endothelial selectin (E-selectin, sE-selectin) levels, which was not abolished by tamoxifen either. Moreover, calcium chelator BAPTA, ERK1/2 inhibitor PD98059, p38 inhibitor SB203580 significantly reduced the production of nicotine-activated surface/soluble VCAM-1 and E-selectin and both of the remained levels were no longer regulated by estrogen. Our study here provides the information of decrease effect of mER-mediated estrogen through Ca2+ and ERK1/2, p38 MAPK signaling pathway on nicotine-stimulated expression of surface/soluble VCAM-1 and E-selectin in HUVECs.     

JWA--a novel environmental-responsive gene, involved in estrogen receptor-associated signal pathway in MCF-7 and MDA-MB-231 breast carcinoma cells

The pyrethroid insecticide fenvalerate and the organophosphorus insecticide phoxim are now the most widely used agents for indoor pest control in China. Fenvalerate was shown to mimic estrogenic activity, whereas phoxim did not induce similar effects. Our previous studies demonstrated that JWA, a novel retinoic acid-inducible and cytoskeleton-associated gene, is also a potential environmental-responsive gene with increased expression to oxidative and heat-shock stresses. In the present study, the influence of both fenvalerate and phoxim was examined on the expression of JWA in MCF-7 (ER+) and MDA-MB-231 (ER-) human breast carcinoma cell lines. Concentrations of 0.01, 1, and 100 micromol/L of fenvalerate or phoxim were selected to treat both MCF-7 and MDA-MB-231 cells at 1, 3, and 5 d, respectively. The MTT results only showed that fenvalerate stimulated MCF-7 cell proliferation. Western blot assay was employed to detect the expressions of JWA and heat-shock proteins (hsp27 and hsp70). The results showed that after treatment with fenvalerate, both JWA and hsp70 showed similar expression patterns in the both cell lines; however, all the expression patterns of JWA, hsp27, and hsp70 were evidently reversed between ER+ and ER- cells. In addition, phoxim-treated cells showed a concentration-dependent relationship in JWA expression at all time points. These results suggest that JWA has similar functions with respect to hsp27 and hsp70, and might be a novel signal molecule in estrogen receptor-related signal transduction pathways in mammalian cells.     

Alkylating drugs applied in non-cytotoxic doses as a novel compounds targeting inflammatory signal pathway

Alkylating drugs (ADs) belonging to the nitrogen mustard family are commonly used as cytostatic and immunosuppressive agents. Our previous in vitro studies demonstrated that in the case of gradual dose decrease, the number of targets for alkylation in the cell is also reduced and the drug switches from brutal cytostatic to cell growth modifier. At doses of 0.3 microg/ml and lower, the effects of ADs are no longer associated with DNA damage or stress/MAPK pathways activation. Instead, the disruption of signal transduction by the IL-2beta and/or TNFalpha cell surface receptors is observed. As a result, ADs in the doses 100-fold lower than cytostatic ones are capable to modify lymphocyte activity including the activity of regulatory T cells. We hypothesized that ADs may have a beneficial effect in the treatment of inflammatory diseases. Indeed, the application of non-cytotoxic doses of an AD melphalan reduces the severity of murine experimental colitis. Daily administration of melphalan (25 microg/kg body weight) markedly reduced the severity of DSS-colitis as determined by clinical and histological criteria. Moreover, the beneficial effect of melphalan was also shown in asthmatic patients. In 60% of these patients histological and ultrastructural signs of bronchial epithelium regeneration were also revealed. Thus, ADs at non-cytotoxic concentrations exert beneficial effect both in acute and chronic inflammatory diseases. Such anti-inflammatory activity is thought to be due to blocking of signal transduction through various cell surface receptor including IL-2R and TNFR. Consequently different steps of inflammatory cascade turn out to be inhibited.     

Altholactone, a novel styryl-lactone induces apoptosis via oxidative stress in human HL-60 leukemia cells

Plant styryl-lactone derivatives isolated from Goniothalamus sp. are potential compounds for cancer chemotherapy. In this study, we have examined the mechanisms of apoptosis induced by altholactone, a stryl-lactone isolated from the Malaysian plant G. malayanus on human HL-60 promyelocytic leukemia cells. Flow cytometric analysis of the externalization of phosphatidylserine (PS) using the annexin V/PI method on altholactone treated HL-60 cells showed a concentration-dependent increase of apoptosis from concentrations ranging from 10.8 (2.5 microg/ml) to 172.4 microM (40 microg/ml). Pre-treatment with the antioxidant N-acetylcysteine (1 mM) completely abrogated apoptosis induced by altholactone, suggesting for the involvement of oxidative stress. Further flow cytometric assessment of the level of intracellular peroxides using the fluorescent probe 2',7'-dichlorofluorescein diacetate (DCFH-DA) confirmed that altholactone induced an increase in cellular oxidative stress in HL-60 cells which was suppressed by N-acetylcysteine. In summary, our results demonstrate for the first time that altholactone induced apoptosis in HL-60 cells occurs via oxidative stress.     

JWA is required for arsenic trioxide induced apoptosis in HeLa and MCF-7 cells via reactive oxygen species and mitochondria linked signal pathway

Arsenic trioxide, emerging as a standard therapy for refractory acute promyelocytic leukemia, induces apoptosis in a variety of malignant cell lines. JWA, a novel retinoic acid-inducible gene, is known to be involved in apoptosis induced by various agents, for example, 12-O-tetradecanoylphorbol 13-acetate, N-4-hydroxy-phenyl-retinamide and arsenic trioxide. However, the molecular mechanisms underlying how JWA gene is functionally involved in apoptosis remain largely unknown. Herein, our studies demonstrated that treatment of arsenic trioxide produced apoptosis in HeLa and MCF-7 cells in a dose-dependent manner and paralleled with increased JWA expression. JWA expression was dependent upon generation of intracellular reactive oxygen species induced by arsenic trioxide. Knockdown of JWA attenuated arsenic trioxide induced apoptosis, and was accompanied by significantly reduced activity of caspase-9, enhanced Bad phosphorylation and inhibited MEK1/2, ERK1/2 and JNK phosphorylations. Arsenic trioxide induced loss of mitochondrial transmembrane potential was JWA-dependent. These findings suggest that JWA may serve as a pro-apoptotic molecule to mediate arsenic trioxide triggered apoptosis via a reactive oxygen species and mitochondria-associated signal pathway.     

Apoptotic pathway induced by noscapine in human myelogenous leukemic cells

It has been shown that noscapine, an opium-derived phthalideisoquinoline alkaloid that is currently being used as an oral antitussive drug, induces apoptosis in myeloid leukemia cells. The molecular mechanism responsible for the anticancer effects of noscapine is poorly understood. In the current study, the apoptotic effects of noscapine on two myeloid cell lines, apoptosis-proficient HL60 cells and apoptosis-resistant K562 cells, were analyzed. An increase in the activity of caspase-2, -3, -6, -8 and -9, poly(ADP ribose) polymerase cleavage, detection of phosphatidylserine on the outer layer of the cell membrane, nucleation of chromatin, and DNA fragmentation suggested the induction of apoptosis. Noscapine increased the Bax/Bcl-2 ratio with a significant decrease of Bcl-2 expression accompanied with Bcl-2 phosphorylation. Using an inhibitory approach, the activation of the caspase cascade involved in the noscapine-induced apoptosis was analyzed. We observed no inhibitory effect of the caspase-8 inhibitor on caspase-9 activity. In view of these results and taking into consideration that K562 cells are Fas-null, we suggested that caspase-8 is activated in a Fas-independent manner downstream of caspase-9. In conclusion, noscapine can induce apoptosis in both apoptosis-proficient and apoptosis-resistant leukemic cells, and it can be a novel candidate in the treatment of hematological malignancies.     

Involvement of intracellular oxidative stress-sensitive pathway in phloxine B-induced photocytotoxicity in human T lymphocytic leukemia cells

We investigated the molecular mechanisms underlying phloxine B (PhB)-induced photocytotoxicity in human T lymphocytic leukemia Jurkat cells. In addition to apoptosis-related biochemical events, photo-irradiated PhB generated intracellular reactive oxygen species (ROS), induced phosphorylation of c-Jun-N-terminal kinase (JNK) in an oxidative stress-dependent manner and up-regulated the gene expression of interferon (IFN)-γ, an inducer of diverse apoptosis-related molecules in activated T cells. PhB-induced apoptosis was significantly inhibited by N-acetyl-l-cysteine, but not by catalase, indicating that ROS generation occurred intracellularly, and by SP600125 and AG490, specific inhibitors of JNK and IFN-γ signaling, respectively, confirming their roles in the apoptotic pathway. IFN-γ up-regulation was also inhibited by SP600125, indicating that it was downstream of JNK activation. These results suggest that PhB-induced apoptosis in Jurkat cells partially involves the intracellular oxidative stress-sensitive and T cell-specific IFN-γ pathway. These data present a novel insight into the mechanisms of photocytotoxicity induced by artificial food colorants in human T lymphocytic leukemia cells.     

Myeloid sarcoma presenting as an isolated nodule in a patient with acute myelogenous leukemia

We report a case of an elderly female in remission from acute myelogenous leukemia that presented with a nonhealing enlarging asymptomatic nodule on her right thigh. A wide excision of the nodule and histological examination revealed myeloid sarcoma without evidence or overlap of leukemia cutis, which had been suspected from nodules that had developed early in the course of the disease. The patient subsequently underwent radiation therapy to the area with sustained clearance.     

Alterations in striatal oxidative stress level produced by pharmacological manipulation of dopamine as shown by a novel synthetic marker molecule

Oxidative stress (OS) is thought to participate in neurodegenerative diseases such as Parkinson's disease, but the contribution of dopamine metabolism and auto-oxidation to OS in Parkinson's and other diseases is not clear. Oxidative stress in rat striatum was measured by microdialysis using a novel synthetic compound composed of tyrosine and linoleic acid (LT), and determination of the oxidation products LT-OOH and LT-epoxy by HPLC-MS. Since LT is non-diffusible through the microdialysis membrane, the oxidized products formed in microdialyzate reflect oxidation state in the extracellular compartment. The extracellular oxidative stress (OS(ec)) was compared with intracellular oxidative stress (OS(ic)) as measured by tissue levels of oxidized and reduced glutathione and 7-ketocholesterol. Reserpinization caused an increase in OS(ic) but a reduction in OS(ec). Inhibition of both subtypes of monoamine oxidase (MAO-A and MAO-B) with tranylcypromine caused a reduction in both OS(ic) and?OS(ec) whereas selective inhibition of MAO-A with clorgyline caused a reduction in Os(ic) but no change in OS(ec). A high dose (10?mg/kg) of amphetamine caused an increase in OS(ec) whereas a smaller dose (4?mg/kg) caused a reduction in OS(ec). Both doses of amphetamine reduced OS(ic). The present findings are consistent with a role of monoamine oxidase as well as dopamine auto-oxidation in production of striatal OS.     

New drugs in acute myelogenous leukemia: a review.

Numerous clinical trials in adult patients with newly diagnosed acute myelogenous leukemia indicate that the survival rate is approximately 20%. A limited number of favorable prognostic features have been identified; patients who present with specific cytogenetic abnormalities such as t(15;17), t(8;21) and inv (16) tend to have survival rates approaching 40%. However, such patients constitute only a small proportion of the total denominator and it has therefore been a major focus of scientific endeavor to develop new drugs for the treatment of this disease. A wide variety of agents have undergone preliminary testing in this regard and include both natural substances such as homoherringtonine, a drug that has demonstrated modest complete remission rates in this disease and all-trans retinoic acid, a compound that has revolutionized the treatment of acute promyelocytic leukemia. This review will put in perspective some of the newer drugs for the treatment of acute myelogenous leukemia and allow for some conclusions to be drawn as to their impact in the treatment of this disease.     

Lenalidomide as a novel treatment of acute myeloid leukemia

Introduction: Lenalidomide is an oral immunomodulatory drug derived from thalidomide. This drug has been approved by the Food and Drug Administration for transfusion-dependent anemia due to low-risk myelodysplastic syndromes (MDS) associated with deletion 5q abnormality with or without additional cytogenetic abnormalities and multiple myeloma in combination with dexamethasone. Trials have been conducted for its use in higher-risk MDS and acute myeloid leukemia (AML).

Areas covered: The pharmacokinetic and mechanism of action are discussed and clinical studies of lenalidomide in AML are reported herein in detail. An overview of safety and tolerability is also presented.

Expert opinion: Lenalidomide has clinical activity in AML with manageable toxicity. The population that would benefit from lenalidomide and optimal dose needs to be better defined. Recent trials have focused on combining lenalidomide with other agents active in MDS and AML and promising data are emerging.     

Mercuric chloride induces apoptosis via a mitochondrial-dependent pathway in human leukemia cells

Mercurial compounds modulate immunologic functions by inducing cytotoxicity. Although mercury chloride (HgCl(2)) is known to induce apoptosis in various immune system cells, the mechanism of the induction of apoptosis is poorly understood. In this study, we examined the activation of caspase-3, an important cysteine aspartic protease, during HgCl(2)-induced apoptosis in a human leukemia cell line (HL-60 cells). Both DNA fragmentation, a characteristic of apoptotic cells, and proteolysis of poly(ADP-ribose) polymerase (PARP), a substrate of caspase-3, occurred at 6 h after HgCl(2) treatment in HL-60 cells. These results suggest that the activation of caspase-3 was involved in HgCl(2)-induced apoptosis. The release of cytochrome c (Cyt c) from mitochondria into the cytosol, which is an initiator of the activation of caspase cascades, was also observed in HgCl(2)-treated HL-60 cells. Moreover, the release of Cyt c from mitochondria was observed in HgCl(2)-treated mitochondria isolated from mice liver, and this was followed by mitochondrial permeability transition (PT). The PT was inhibited by cyclosporin A (CsA), a potent inhibitor of PT. CsA also suppressed the occurrence of DNA fragmentation induced by HgCl(2) treatment in HL-60 cells. Taken together, these findings indicate that HgCl(2) is a potent inducer of apoptosis via Cyt c release from the mitochondria in HL-60 cells.     

Tyrosine kinase inhibitor as a therapeutic drug for chronic myelogenous leukemia and gastrointestinal stromal tumor

The Philadelphia chromosome found in leukemia cells of chronic myelogenous leukemia (CML) patients is produced by translocation between chromosomes 9 and 22, resulting in expression of a chimera protein of Bcr and Abl kinase in the cytoplasm. Bcr-Abl kinase attracted oncology researchers as a molecular target for CML therapy, and a variety of small Abl kinase inhibitors were synthesized. STI571 (imatinib mesylate) was produced by modification of 2-phenylaminopyrimidine, a core structure of protein kinase C inhibitor, to improve selectivity, stability, solubility, and bioavailability. STI571 competitively binds to the ATP binding site of Bcr-Abl kinase and inhibits Abl tyrosine kinase activity. STI571 showed significant efficacy in the clinical study with CML patients at all stages: chronic phase, accelerated phase, and blast crisis. More than 90% of the patients showed good hematologic response to STI571. STI571 is also a potent inhibitor of a receptor-type c-Kit tyrosine kinase. Therefore, STI571 was examined for therapeutic efficacy against malignant Gastro-Intestinal Stromal Tumors (GIST), which are mainly caused by aberrant expression of a mutated c-Kit that is constitutively active without binding of a ligand, stem cell factor (SCF). More than a half of the metastatic GIST patients enrolled in the clinical study responded to STI571. Thus, STI571 is now used as a therapeutic drug for both CML and GIST in more than 80 countries worldwide. Certain point mutations in the ATP binding site were found to be a cause of resistance to STI571 in both Bcr-Abl and c-Kit kinases. Therefore, it would be better to make a precise therapeutic strategy with STI571 based on the gene analysis data. It is also expected that it will be possible to design an inhibitor to overcome such resistance by using the structural information on the mutants.     

VX-322: a novel dual receptor tyrosine kinase inhibitor for the treatment of acute myelogenous leukemia

In acute myelogenous leukemia (AML), the FLT3 receptor tyrosine kinase (RTK) is highly expressed with 30% of patients expressing a mutated, constitutively active form of this protein. To inhibit this receptor, VX-322 was developed and found to be very potent against both the FLT3 and c-KIT RTKs with enzyme K(i) values of <1 nM and a cellular IC(50) between 1 and 5 nM. It was efficacious in a FLT3-ITD dependent myeloproliferative mouse model, doubling survival compared to other FLT3 inhibitors, with 25% of the mice cured. Upon treatment of primary AML patient blast cells, the dual inhibition of FLT3 and c-KIT was superior to inhibitors targeting a single RTK. Thus, this compound may represent an improved pharmacologic and selectivity profile that could be effective in the treatment of AML.     

A model to identify novel targets involved in oxidative stress-induced apoptosis in human lung epithelial cells by RNA interference

Chronic obstructive pulmonary disease (COPD) is an increasing health problem primarily associated with cigarette smoking, and one of the leading causes of morbidity and mortality worldwide. Despite recent advances in understanding the pathogenesis of the disease, overall patient outcome remains poor with limited therapeutic intervention. Chronic inflammation, an imbalance between proteolytic and anti-proteolytic activities (leading to lung parenchyma destruction) and excessive oxidative stress contribute to COPD pathophysiology. Oxidative stress-triggered apoptosis of alveolar structural cells, including epithelial cells, may be an important event in the development of COPD. In this study, we developed a cell-based oxidative stress-induced apoptosis assay and performed a high-throughput screen (HTS) using a human druggable genome siRNA library. Our results have identified potential novel pathways (e.g. unfolded protein response, proteosomal activity) and targets (e.g. MAP3K14, HMGB2) that regulate the response of lung epithelial cells to oxidative stress. This assay has proven to be a useful tool for the identification of potential new therapeutic targets for lung disease.     

The adiponectin signaling pathway as a novel pharmacological target

There appear to be compelling evidences presenting adiponectin as a key regulator of energy homeostasis. Over the past 10 years, much work has been done to identify the molecular mechanisms by which adiponectin functions in the body. We and other groups have demonstrated that adiponectin activates multiple signaling pathways, which mediate its anti-diabetic, anti-atherogenic and anti-inflammatory functions. Comprehensive analysis of the mechanism of adiponectin action may allow us to elucidate the etiology of metabolic syndrome associated diseases including diabetes and cardiovascular diseases, where dysfunction of adiponectin may contribute to pathogenesis of diseases. While regulation of adiponectin gene expression or secretion remains an interesting topic in studies of cell metabolism, further intensive studies are necessary to illustrate the molecular mechanisms. Importantly, identification of molecules in the adiponectin signaling pathways and in the regulation of adiponectin gene expression may provide novel targets for therapeutic drugs.     

Discovery and structure–activity relationship of plastoquinone analogs as anticancer agents against chronic myelogenous leukemia cells

Two series of amino‐1,4‐benzoquinones ( AQ1–18 ) based on the structural analogs of plastoquinones were synthesized and the structure–activity relationship against chronic myelogenous leukemia activity was examined. All of the synthesized compounds were tested for their cytotoxic effects on different leukemic cell lines. Of interest, AQ15 exhibited a better selectivity than the reference drug imatinib on cancer cells. Owing to this, AQ15 was selected for a further apoptosis/necrosis evaluation where AQ15 ‐treated K562 cells demonstrated similar apoptotic effects like imatinib‐treated cells at their IC₅₀ values. The inhibitory effects of AQ15 and the other three compounds with various activities against eight tyrosine kinases, including ABL1, were investigated. AQ15 showed weak activity against ABL1, and a correlation was observed between the anti‐K562 and anti‐ABL1 activities. The binding mode of AQ15 into the ATP binding pocket of ABL1 kinase was predicted in silico, showing the formation of some key interactions. In addition, AQ15 was shown to suppress the downstream signaling of BCR‐ABL in K562 cells. Finally, AQ15 obviously cleaved DNA in the presence of an iron(II) complex system, indicating that this can be the major mechanism of its antiproliferative action, whereas the mild inhibition of ABL kinase is just in‐part mechanism of its overall outstanding cellular activity.     

治疗急性骨髓性白血病新药恩西地平

急性骨髓性白血病是成人常见的白血病类型,发病率随年龄的增长而升高,病情进展迅速,严重威胁人类健康。恩西地平（Enasidenib,Idhifa^®）是第一个异柠檬酸脱氢酶2抑制剂,能有效治疗该酶变异导致的急性骨髓性白血病,也是美国食品药品管理局批准的唯一一个针对这一患者群体的肿瘤代谢疗法新药。对恩西地平的作用机制、药效学、药动学、药物相互作用、临床评价和安全性等进行综述,旨在为临床应用提供有益的参考。