Publications (190) View all
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Article: 12S-Lipoxygenase is Necessary for Human Vascular Smooth Muscle Cell Survival.
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ABSTRACT: Considerable evidence has been published demonstrating the importance of lipoxygenase enzymes for vascular smooth muscle cell (VSMC) growth. The current study sets out to determine whether or not 12-Lipoxygenase (12LO) is also important for human placental VSMC survival. Both a pharmacological and two 12LO antisense knockdown approaches were applied. The 12LO inhibitor baicalien induced a 2-2.5 fold increase in cell death, which appeared to result from apoptosis, as indicated by DNA fragmentation, activation of procaspase3 to caspase 3 and cytochrome C release from the mitochondria to the cytosol. This apoptosis could be prevented by treatment with the 12LO product, 12 hydroxyeicosatetraenoic acid (12HETE). Human platelet-type 12LO-antisense knockdown, by either plasmid transfection or adeno-associated virus (AAV) infection also induced substantial VSMC death over controls, which also could be prevented by treatment with 12HETE, but not 5HETE. Hence, biochemical 12LO inhibition or 12LO-antisense knockdown in VSMC can induce programmed cell death. These observations suggest a previously unrecognized association between human VSMC survivability and 12LO.Experimental Cell Research 04/2013; · 3.58 Impact Factor -
Article: Vitamin D less-calcemic analog modulates the expression of estrogen receptors, vitamin D receptor and 1α-hydroxylase 25-hydroxy vitamin D in human thyroid cancer cell lines.
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ABSTRACT: Estrogen receptors (ERs) are expressed in various "non-reproductive" cancer cell types. Some cancer types express 1α-hydroxylase 25-hydroxy vitamin D (1OHase) whose product, 1,25(OH)(2)D(3) can retard cancer cell proliferation. Thyroid carcinoma cell growth is apparently promoted by estrogens, but whether or not this interaction is modified by vitamin D metabolites/analogs is presently unknown. Here we assessed the effect of a less calcemic vitamin D analog [JK 1624 F(2)-2 (JKF)] in three human thyroid cancer cell lines: ARO (anaplastic carcinoma), NPA (papillary carcinoma) and MRO (follicular carcinoma). (1) All cell lines expressed both ERα and ERβ, vitamin D receptor (VDR) and 1OHase mRNA quantified by Real Time PCR. There was a general abundance of ERβ over ERα expression, such that the ratio of ERβ to ERα mRNA was >1000:1, 228:1 and 7.7:1 in ARO, MRO and NPA cells, respectively. (2) JKF up regulated ERβ expression in ARO (by 110±15%) and MRO (by 280±10%) but down regulated ERβ in NPA cells (by 40±15%). The expression of VDR was up regulated by JKF in NPA (21±6%), down regulated in ARO (-24±7%) and not affected in MRO. (3) All three human thyroid cancer cell lines were found to express 1OHase, which was up regulated by JKF in MRO (350±25%) and NPA (35±8%) but down regulated in ARO (-20±5%). This is the first report to describe direct regulation of VDR and 1OHase expression by a vitamin D analog in human thyroid cancer cells. A functional role for the vitamin D system in human thyroid cancer is suggested by the finding that the vitamin D analog can affect ERs expression which is in turn involved in estrogen-induced cell growth in an ER-type specific manner in these cells.The Journal of steroid biochemistry and molecular biology 10/2012; · 2.66 Impact Factor -
Article: Anti-thyroid cancer properties of a novel isoflavone derivative, 7-(O)-carboxymethyl daidzein conjugated to N-t-Boc-hexylenediamine in vitro and in vivo.
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ABSTRACT: The incidence of thyroid cancer is up to 3 folds higher in women than in men, suggesting that estrogenic effects may be involved in the pathogenesis of this malignancy. Here, we explore whether or not human thyroid cancer cell growth can be curbed by a novel isoflavone derivative generated in our laboratory, the N-t-Boc-hexylenediamine derivative of 7-(O)-carboxymethyl daidzein (cD-tboc). With the exception of the follicular cancer cell line WRO, estrogen receptor (ER)α mRNA was only marginally expressed in cell lines derived from papillary (NPA), follicular (MRO), anaplastic thyroid carcinoma (ARO) such that the expression of estrogen receptor (ER) βmRNA was more abundant than that of ERα mRNA in these cell types. Estradiol-17β (E2; 0.03-300nmol/l) per se increased proliferation in all four cell-types. The ERβ-specific agonist DPN increased [(3)H]-thymidine incorporation in all four thyroid cancer cell lines, whereas the ERα-specific agonist PPT increased growth only in NPA and WRO. By contrast, cD-tboc, derived from the weak estrogen daidzein, did not cause cell growth and dose-dependently diminished cell growth in all four cell lines via apoptosis and not necrosis, as detected by the release of histone-DNA fragments. The cytotoxic growth inhibitory effect of cD-tboc in these cells was modulated by E2 and the general caspase inhibitor Z-VAD-FMK, and the magnitude of this salvage was cell type-and dose-dependent. When nude mice carrying ARO thyroid xenografts were treated with cD-tboc, tumor volume decreased significantly, and no apparent toxicity was observed. These results suggest that cD-tboc may be a promising agent for therapy of thyroid carcinoma either alone or in combination with existing cytotoxic drugs.The Journal of steroid biochemistry and molecular biology 05/2011; 126(3-5):95-103. · 2.66 Impact Factor -
Article: The effects of estrogen receptors α- and β-specific agonists and antagonists on cell proliferation and energy metabolism in human bone cell line.
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ABSTRACT: In cultured human osteoblasts estradiol-17β (E2) modulated DNA synthesis, the specific activity of creatine kinase BB (CK), 12 and 15 lipoxygenase (LO) mRNA expression and formation of 12- and 15-hydroxyeicosatetraenoic acid (HETE). We now investigate the response of human bone cell line (SaOS2) to phytoestrogens and estrogen receptors (ER)-specific agonists and antagonists. Treatment of SaSO2 with E2, 2,3-bis (4-hydroxyphenyl)-propionitrile (DPN; ERβ-specific agonist), 4,4',4″-[4-propyl-(1H)-pyrazol-1,3,5-triyl] tris-phenol (PPT; ERα-specific agonist), biochainin A (BA), daidzein (D), genistein (G) and raloxifene (Ral) showed increased DNA synthesis and CK. Ral inhibited completely all stimulations except DPN and to some extent D. The ERα-specific antagonist methyl-piperidino-pyrazole (MPP) and the ERβ-specific antagonist 4-[2-phenyl-5,7-bis (tri-fluoro-methyl) pyrazolo [1,5-a]pyrimidin-3-yl] phenol (PTHPP) inhibited DNA synthesis, CK and reactive oxygen species (ROS) formation induced by estrogens according to their receptors affinity. The LO inhibitor baicaleine inhibited only E2, DPN and G's effects. E2 and Ral unlike all other compounds had no effect on ERα mRNA expression, while ERβ mRNA expression was stimulated by all compounds. All compounds modulated the expression of 12LO and 15LO mRNA, except E2, PPT and Ral for 12LO, and 12- and 15-HETE productions and stimulated ROS formation which was inhibited by NADPH oxidase inhibitors diphenyleneiodonium chloride (DPI) and N-acetyl cysteine and the estrogen inhibitor ICI. DPI did not affect hormonal-induced DNA and CK. In conclusion, we provide evidence for the separation of mediation via ERα and ERβ pathways in the effects of estrogenic compounds on osteoblasts, but the role of LO/HETE/ROS is unclear.Journal of Cellular Biochemistry 02/2011; 112(2):625-32. · 2.87 Impact Factor -
Article: Bone loss in ovariectomized rats: dominant role for estrogen but apparently not for FSH.
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ABSTRACT: Estrogen deficiency as the sole factor underlying post-menopausal osteoporosis was challenged, in light of reports that both follicular stimulation hormone (FSH) receptor and FSHβ knockout mice were resistant to bone loss, suggesting a detrimental role for FSH. We assessed whether lowering FSH levels by gonadotropin realizing (GnRH) analog decapeptyl in ovariectomized female rats (OVX) affects bone. Wistar-derived 25 days old OVX female rats were injected for 10 weeks with estradiol-17β (E(2)), with GnRH analog (decapeptyl) or with both. FSH and luteinizing hormone (LH) serum levels were markedly increased in OVX rats, with smaller growth plates with disrupted architecture; heavy infiltration of bone marrow with numerous adipocytes and reduced thickness of cortical bone. In OVX rats treated with E(2), FSH, and LH levels were intermediate, the tibia was similar to that of intact rats, but there was reduced thickness of cortical bone. In decapeptyl treated OVX rats, FSH and LH levels were suppressed, the organization of growth plate and the trabecular bone were disrupted, and there were fewer proliferative and chondroblastic cells and a large adipocytes population in bone marrow, but an increased trabecular bone volume (TBV). In the E(2) + decapeptyl treatment, FSH and LH levels were suppressed, with partially restored growth plate architecture and improved TBV. In conclusion, E(2) deficiency is the dominant factor impairing bone loss in OVX and concomitant changes in FSH/LH levels achieved by decapeptyl have some modulating, though complex role in this setting. The role of high FSH levels in post-menopausal bone loss requires further investigation using combined sub-optimal doses of the different hormones.Journal of Cellular Biochemistry 11/2010; 112(1):128-37. · 2.87 Impact Factor
