Effect of human chorionic gonadotropin (hCG) on expression of vascular endothelial growth factor a (VEGF-a) in human mid-secretory endometrial cells in three-dimensional primary culture

Several lines of evidence suggest that human uterine endometrial cells can bind human chorionic gonadotropin (hCG) which, in turn, influences the physiology of implantation stage endometrium. Vascular endothelial growth factor (VEGF) appears to be a candidate mediator in this process. However, our knowledge about hCG action on VEGF in human endometrial cells is very thin. In the present study, we have examined microscopically hCG binding to dissociated human endometrial cells collected from mid-luteal phase and maintained in three-dimensional primary co-culture on rat-tail collagen type I biomatrix and examined the effect of different concentrations (0, 1, 10, 100 and 1000 IU/ML) of hCG on VEGF expression and secretion by endometrial cells maintained in the above system. We report that both cytokeratin positive epithelial cells as well as vimetin positive stromal cells from human mid luteal phase endometrium could bind hCG and that their number increased (P < 0.01) steadily with time. Administration of hCG enhanced (P < 0.05) immunoreactive VEGF protein expression in dose dependent manner in endometrial cells retrieved from mid-luteal phase of cycle, and co-cultured in a three-dimensional cell culture system, but with no marked change in VEGF secretion. Collectively, it appears that hCG influences VEGF protein synthesis in human midluteal phase endometrial cells, but has little effect on post-translational regulation and secretion. From physiological homeostasis point of view, it is likely that synthesis and secretion of VEGF exhibits a modular and factorial regulation to achieve a fine tuning of this potent vasotropic agent in receptive stage endometrium.     

超排卵着床期小鼠子宫内膜LIF表达与雌孕激素的关系

目的 研究超排卵对围着床期小鼠子宫内膜UF表达的影响及其与雌孕激素的关系,探讨超排卵是否影响子宫内膜容受性的形成.方法 将实验动物随机分为超排卵妊娠组和正常妊娠对照组,分别选取动情周期当天、合笼后发现阴道栓第2天、第4天、第6天、第8夫共五个时间点取小鼠子宫内膜,用免疫组化和原位杂交法测定小鼠子宫内膜LIF的蛋白表达和LIF mRNA的表达.同时分别测定小鼠血清雌、孕激素水平.结果 正常妊娠组小鼠LIF蛋白在围着床期子宫内膜上的表达动情周期较低,在妊娠之后开始上升,在妊娠第4天(即小鼠孕卵着床当天)达到最高峰(P<0.05),继之在子宫内膜的表达下降.在妊娠第8天降到非孕期水平:超排卵组小鼠围着床期子宫内膜LIF蛋白随着妊娠天数而表达增加,在妊娠第2天达到最高峰(P<0.05),继之在子宫内膜的表达下降,在妊娠第8天降至非孕期水平.超排卵组与对照组相比较,其在妊娠第2天的表达明显高于对照组(P<0.05),在妊娠第4天的表达明显低于对照组(P<0.05);超排卵组和对照组小鼠血清雌、孕激素浓度均随妊娠天数的增加逐渐升高.在各时间点超排卵组的雌、孕激素水平明显高于对照组(P<0.05).小鼠子宫内膜LIF蛋白的表达与雌激素水平在一定范嗣内成正相关,超过一定临界水平后呈负相关(P<0.05),而与孕激素未发现有相关性(P>0.05).结论 超排卵可能对小鼠围着床期子宫内膜LIF蛋白的表达有影响,使其表达峰值提前,由此推测影响子宫内膜容受性的建立;体内雌激素水平与同着床期子宫内膜LIF蛋白的表达有相关性,但尚不能排除孕激素水平与其有相关性,说明LIF蛋白的表达与雌激素的调控有关,并且可能存在一定的数量关系.     

白血病抑制因子影响人子宫内膜间质细胞血管内皮生长因子表达的体外研究

目的 探讨白血病抑制因子(LIF)在体外条件下对人子宫内膜间质细胞(hESCs)血管内皮生长因子(VEGF)生成的影响,以及VEGF在体外诱导人脐静脉内皮细胞(HUvECs)形成管腔的能力.方法 体外培养分泌期hESCS,加不同浓度LIF处理24 h.半定量RT-PCR方法检测hESCs VEGF mRNA的表达;Western blot方法检测hESCs细胞沉淀中VEGF蛋白的表达以及培养上清中VEGF蛋白的分泌;收集各组hESCs的培养上清,加入在Matrigel上平铺生长的HUVECs细胞中,观察HUVECs在体外形成管腔的能力.结果 与对照组相比,LIF处理组能明显增加hESCs VEGF mRNA水平的表达,明显增加hESCS VEGF蛋白的表达和分泌;hESCs经LIF处理后的培养上清,能明显增加HUVECs形成新生血管的能力.结论 LIF可能通过增加hESCs VEGF的表达参与调控胚胎着床过程中的血管形成.     

Effect of vaginally administered fumagillin on immunohistochemical distribution of leukemia inhibitory factor,interleukin 6, transforming growth factor beta and vascular endothelial growth factor in implantation stage endometrium of the rhesus monkey

Intravaginal administration of an anti-angiogenic agent, fumagillin, during blastocyst implantation inhibits pregnancy establishment in a dose-related manner in the rhesus monkey. In the present study, mated female rhesus monkeys were vaginally inserted with tampons containing vehicle (group 1; n = 5) and test agent (fumagillin, 4 mg/animal; group 2; n = 6) on cycle day 20, and endometrial tissue samples were collected on cycle day 24 from all monkeys and processed for histological examination and immunohistochemical localization for LIF, IL-6, TGF-beta and VEGF. Concentrations of estradiol-17 beta, progesterone and chorionic gonadotrophin in peripheral circulation were determined. From the serum profiles of the hormones, 2 monkeys in group 1, and 1 monkey in group 2 appeared pregnant. However, endometrial morphology revealed histological evidence of pregnancy in 3 out of 6 fumagillin-treated animals. Histometric analysis of immunohistochemical staining in epithelial, stromal and vascular compartments revealed that per cent areas occupied by immunoprecipitate for the cytokines studies did not change in epithelial and stromal compartments, except that for TGF-beta which was higher (P < 0.05) in epithelial compartment in group 2. No change was observed in immunoprecipitation areas for IL-6 in epithelial, stromal and vascular compartments. On the other hand, changes (P < 0.05) for LIF, TGF-beta and VEGF were evident in the vascular compartment. It is possible that disparate responses observed in glandular, stromal and vascular compartments in implantation stage endometrium following fumagillin treatment actually caused from associated decline in progesterone concentration in peripheral circulation. It is also possible that fumagillin, an angiostatic agent, affects the synthesis and secretion of cytokines primarily in the vascular compartment of implantation stage endometrium, and thereby manifests differential responses in epithelial, stromal and vascular compartments.     

Developmental exposure to corticosterone: behavioral changes and differential effects on leukemia inhibitory factor (LIF) and corticotropin-releasing hormone (CRH) gene expression in the mouse

Rationale Cytokines are found in both the peripheral and central nervous system. There has been increasing interest in their potential role in some of the behavioral features of depressive disorders. Leukemia inhibitory factor (LIF), a proinflammatory cytokine, produces stimulation of adrenocorticotropic hormone (ACTH) secretion in response to emotional and inflammatory stress and recently has been linked to depressive-type behavior. Both the hypothalamic–pituitary–adrenal axis and the immune system, including cytokine-mediated responses, appear to be susceptible to long-term programming during fetal and neonatal development. Objective The present study was designed to characterize the effects of perinatal exposure to corticostereone on behavior, hypothalamic LIF and corticotropin-releasing hormone (CRH) mRNA expression, and basal plasma corticosterone levels in adult female mice. Methods Corticosterone was added to the drinking water beginning the last week of gestation and continued until weaning. Behavior in the open field and forced swim tests, baseline plasma corticosterone levels, and hypothalamic LIF and CRH gene expression were evaluated in the adult offspring. Results Mice exposed to perinatal corticosterone showed increased immobility in the forced swim test and increased locomotor activity in the open field test. Although there were no differences between treatment groups in terms of basal plasma levels of corticosterone or hypothalamic CRH mRNA, LIF mRNA expression was increased in the hypothalamus. Conclusions These results show that perinatal exposure to glucocorticoids can produce long-term behavioral changes and upregulation of central LIF mRNA expression.     

Urothelium-derived inhibitory factor(s) influences on detrusor muscle contractility in vitro

The function of the bladder urothelium in modulating contractile responses of the underlying detrusor smooth muscle to muscarinic stimulation has been examined in the pig bladder. Saturation curves for [3H]-QNB binding demonstrated a greater muscarinic receptor density in the urothelium than in the detrusor smooth muscle. The presence of an intact urothelium on isolated bladder strips inhibited contractions induced by carbachol but not KCl. Contractions of a urothelium-denuded muscle strip were inhibited in the presence of a second bladder strip with an intact urothelium, but not if the second strip was denuded. The urothelium-induced inhibition of contractions was not prevented in the presence of L-NOARG, methylene blue, indomethacin, propranolol, suramin, TEA or apamin. The data suggest the presence of a diffusable, urothelium-derived inhibitory factor, which could not be identified but appears to be neither nitric oxide, a cyclo-oxygenase product, a catecholamine, adenosine, GABA nor an EDHF sensitive to apamin.     

重组人白血病抑制因子体外诱导HL-60细胞凋亡与bcl-2及p53表达的关系

目的 :探讨重组人白血病抑制因子 (rh LIF)诱导HL 6 0细胞凋亡的作用及其可能机制。方法 :不同剂量 (10～ 4 0 0 0U·ml-1)的rh LIF作用HL 6 0细胞 3d后 ,用流式细胞仪观察分析细胞周期变化并检测细胞凋亡率 ,用TUNEL法检测原位细胞凋亡情况 ;分别用免疫组化法和原位杂交法检测rh LIF作用 2、4、6d后P5 3蛋白及p5 3mRNA、bcl 2mRNA表达水平的改变。结果 :rh LIF (10～ 4 0 0 0U·ml-1)作用d 3,细胞凋亡率较对照组显著增加 ,其中以10 0 0U·ml-1组的作用最强 ;rh LIF (80 0U·ml-1)作用 2～ 6d ,P5 3蛋白和p5 3mRNA表达也同步增高 ,而bcl 2mRNA表达显著降低 (P <0 .0 1)。结论 :rh LIF能诱导HL 6 0细胞凋亡 ,该作用与P5 3蛋白表达增加和bcl 2表达降低有关     

In vitro inhibitory effects of palonosetron hydrochloride,bevacizumab and cyclophosphamide on purified paraoxonase-I (hPON1) from human serum

In this study, we investigated the effects of the drugs, palonosetron hydrochloride, bevacizumab and cyclophosphamide, on human serum paraoxonase-I (hPON1) enzyme activity in in vitro conditions. The enzyme was purified ∼231-fold with 34.2% yield by using ammonium sulphate precipitation, DEAE-Sephadex A-50 ion-exchange chromatography and Sephadex G-200 gel-filtration chromatography from human serum. hPON1 exhibited a single protein band on the SDS polyacrylamide gel electrophoresis. The inhibition studies were performed on paraoxonase activity of palonosetron hydrochloride, bevacizumab and cyclophosphamide. K_i constants were found as 0.033 ± 0.001, 0.054 ± 0.003 mM and 3.419 ± 0.518 mM, respectively. Compared to the inhibition rates of the drugs, palonosetron hydrochloride has the maximum inhibition rate. However, inhibition mechanisms of the drugs were determined as noncompetitive by Lineweaver-Burk curves.     

In vitro antiproliferative activity of 4-substituted 2-(2-hydroxyphenyl)thiazolines on murine leukemia cells

Two previously synthesized and two structurally novel thiazoline iron chelators are described. N4-Benzyl-N1,N8-bis[[2-(2-hydroxyphenyl)thiazolin-4-yl]carbonyl] homospermidine (5) proved to be the most potent antiproliferative and cytocidal compound in the series with in vitro IC50 values of 3 and 1 microM on L1210 and P388 murine cell lines. The N4-acetyl analogue 7 was considerably less active than 5 with IC50 and cell viability values that were similar to those of the structurally simple thiazolines 2 and 3. The antiproliferative activity of 3 and 7 could be substantially reduced or ablated by delivery to cell suspensions as a 1:1 molar mixture with FeCl3, while the activity of 5 was unaffected by Fe(III) chelation. As expected, 3 induced a G1/S cell cycle block at the 100 microM block consistent with interference with DNA synthesis while 10 microM 5 did not affect L1210 cell cycle distribution. Tritiated thymidine incorporation studies confirmed that 5 was incapable of interfering with DNA synthesis at concentrations below 40 microM. Alkaline elution studies indicate that 5 does not cause DNA strand breaks in vitro at concentrations of 10 microM. The N4-benzyl group of 5 appears to impart in vitro potency as the N4-acetyl analogue 7 lacks comparable in vitro antiproliferative and cytocidal activity.     

川芎嗪体外对活化T细胞的抑制作用

目的 研究川芎嗪体外对活化T细胞的作用及机制.方法 应用植物血凝素(PHA)刺激正常人外周血T细胞,经川芎嗪处理后,应用四甲基偶氮唑盐(MTT)微量酶反应比色法榆测细胞增殖,流式细胞术检测CD4+和CD8+T细胞上CD25(白细胞介素-2受体,IL-2R)及负性协同刺激分子程序性死亡分子1(PD-1)的表达,ELISA法检测细胞因子IL-2水平变化.结果 川芎嗪(150μg/ml)处理72 h后,能明显抑制T细胞的增殖和活化(P＜0.01),并降低IL-2水平(P＜0.01);能抑制CD4+和CD8+T细胞上IL-2R的表达(P＜0.05);对负件协同刺激分子PD-1的表达作用不明显(P＞0.05).结论 川芎嗪对免疫过激T细胞具有一定的抑制作用,其对T细胞的免疫抑制作用可能与降低IL-2的分泌和抑制IL-2R(CD25)的表达有关.     

(-)-Menthol inhibits WEHI-3 leukemia cells in vitro and in vivo

(-)-Menthol ([1-alpha]-5-methyl-2-[1-methylethyl]-cyclohexanol), is a widely used flavoring ingredient in mouthwash, foods, toothpaste and cigarettes. The studies reported here revealed that (-)-menthol induced cytotoxicity against murine leukemia WEHI-3 cells in vitro in a dose-dependent manner. The effects of (-)-menthol on WEHI-3 cells in vivo (BALBIc mice) were also examined, and it was observed that the Mac-3 and CD11b markers were decreased, indicating inhibition of differentiation of the precursor of macrophage and granulocyte. The weights of liver and spleen samples from mice treated with (-)-menthol were found to be decreased compared to untreated animals.     

In vitro inhibitory effect of protopanaxadiol ginsenosides on tumor necrosis factor (TNF)-alpha production and its modulation by known TNF-alpha antagonists

Ginsenosides are the major principles of Panax ginseng C. A. Meyer (Araliaceae) used as a mild oriental folk medicine. In this report, we have examined the inhibitory potency of protopanaxadiol ginsenosides (PPDGs) such as Rb1, Rb2 and Rc, and their co-treatment effect with known tumor necrosis factor (TNF)-alpha antagonists on TNF-alpha production in either murine (RAW264.7) or human (U937) macrophages stimulated with lipopolysaccharide (LPS). Rb1, and Rb2 strongly suppressed TNF-alpha production in RAW264.7 cells with an IC50 of 56.5 and 27.5 microM, respectively, and in differentiated U937 cells with an IC50 of 51.3, and 26.8 microM, respectively. The inhibitory activity of Rb1 and Rb2 was significantly increased by pharmacological agents against protein kinase C, protein tyrosine kinase, and protein kinase A, and anti-rheumatoid arthritis drugs, such as chloroquine and steroid drugs. In contrast, only cyclic AMP phosphodiesterase (cAMP PDE) inhibitors among cAMP-elevating agents did not change the inhibitory potency of PPDGs. These data suggest that PPDGs may possess potential therapeutic efficacy against TNF-alpha mediated disease and the therapeutic potency of PPDGs may be enhanced when co-treated with various kinds of known TNF-alpha antagonists but not with cAMP PDE inhibitors.     

Platelet-activating factor (PAF) inhibitory profile of KO-286011 on blood platelets in vitro and in vivo

Summary A newly synthesised structural analogue of PAF, coded KO-286011 (1-O-hexadecyl-2-O-ethyl-racglycero-3-phosphoric acid 4-(N,N-dimethylamino)pyridinium butylester), was proved for its ability to inhibit PAF-mediated platelet responses in vitro and in vivo. The compound inhibited effectively the PAF-induced aggregation and secretion of human and rabbit platelets. In contrast, there was little influence on ADP-, collagen-, and arachidonic acid-triggered platelet responses. Schild-analysis of aggregation data ascertained in human platelet-rich plasma was consistent with a simple competitive antagonism and yielded a pA₂, of 6.44. Pro-aggregatory activity of KO-286011 was excluded turbidimetrically as well as by means of a single cell counting technique. [³H]PAF binding studies provided evidence that KO-286011 exerts its inhibitory action at the PAF-receptor level. A significant inhibition of the ex vivo PAF-induced platelet aggregation was found after i.v. administration of 0.5 mg/kg KO-286011 to rabbits. The effect was most pronounced 5 min after dosing the inhibitor and detectable over a period of 30 min. Intravenous administration of 10 and 25 μg/kg KO-286011 to guinea pigs prevented dose-dependently the PAF-induced formation of thromboxane A₂. The PAF-inhibitory action of KO-286011 was more potent than that of the ginkgolide BN 52021. Send offprint requests to G. Ostermann at the above address     

In vitro and in vivo inhibitory activities of rutin,wogonin, and quercetin on lipopolysaccharide-induced nitric oxide and prostaglandin E(2) production

Flavonoids are widely distributed in plants, but their biological functions are still unclear. In the present study, in vitro and in vivo experiments were performed to demonstrate the inhibitory activities of rutin, wogonin, and quercetin on lipopolysaccharide-induced nitric oxide (NO) and prostaglandin E(2) production in RAW 264.7 macrophages, primary peritoneal macrophages, and Balb/c mice, respectively. In vitro results showed that wogonin and quercetin dose-dependently suppressed lipopolysaccharide-induced NO production in RAW 264.7 macrophages and primary peritoneal macrophages without a notable cytotoxic effect on either cell types associated with a decrease in inducible nitric oxide synthase (iNOS) protein expression in both cells. Rutin, at 80 microM only, had a slight but obvious inhibitory effect on lipopolysaccharide-induced NO production in primary peritoneal macrophages. Both wogonin and quercetin attenuated lipopolysaccharide-induced prostaglandin E(2) production in vitro. Intravenous injection of lipopolysaccharide (10 mg/kg, i.v.) resulted in a time-dependent induction of NO production in serum, and pretreatment with the L-arginine analog N-nitro-L-arginine methyl ester (L-NAME) blocked this induction. Intravenous pretreatment of Balb/c mice with rutin, wogonin or quercetin for 1 h followed by lipopolysaccharide treatment significantly inhibited lipopolysaccharide-induced NO production, but no inhibition of prostaglandin E(2) production was found. A decrease in iNOS protein, but not cyclooxygenase-2 protein, was detected in liver and lung specimens of lipopolysaccharide-treated Balb/c mice in the presence of rutin, wogonin or quercetin. In conclusion, data obtained both in vitro and in vivo suggest that wogonin and quercetin exert inhibitory activity on lipopolysaccharide-induced NO production through suppression of iNOS expression.     

The diverse mechanism of action of dichlorodiphenyldichloroethylene (DDE) and methoxychlor in ovarian cells in vitro

Dichlorodiphenyldichloroethylene (DDE), the most stable metabolite of the organochlorine insecticide dichlorodiphenyltrichloroethane (DDT), and the DDT analog methoxychlor can have adverse effects on reproduction. These chemicals have been identified as having estrogenic activity. The aim of the current study was to examine the effects of dichlorodiphenyldichloroethylene (DDE), methoxychlor, and estradiol-17β on steroidogenesis and FSH responsiveness in ovarian cells in vitro. Experiments were performed on a primary culture of porcine granulosa cells and a culture of Chinese hamster ovary (CHO) cells, the latter stably transfected with the FSH receptor (CHO-FSH-R). DDE (10 μM) and estradiol-17β (0.1 μM) but not methoxychlor (10 μM), increased proliferation of the granulosa cells. DDE (100 and 10 μM, respectively) decreased FSH-stimulated cAMP synthesis in the granulosa and CHO-FSH-R cells. DDE also decreased progesterone synthesis in the granulosa cells. Methoxychlor (10 μM) inhibited progesterone synthesis in the granulosa cells, but it did not affect the generation of cAMP in either type of cells studied. However, methoxychlor inhibited estradiol-17β-stimulated progesterone synthesis in the granulosa cells. We conclude that DDE primarily inhibited the generation of cAMP, while methoxychlor supressed progesterone synthesis through a mechanism distal to cAMP generation. The present results indicate that DDE and methoxychlor are not limited to a mimicking of the endocrine effects of estradiol-17β in cultured ovarian cells. Therefore, a non-estrogenic component of the endocrine disrupting activities of DDE and methoxychlor must be considered in evaluating their reproductive toxicity.     

In vitro effects of bryostatin 1 on the metabolism and cytotoxicity of 1-beta-D-arabinofuranosylcytosine in human leukemia cells

Bryostatin 1 is a macrocyclic lactone protein kinase C (PK-C) activator which has demonstrated promising antileukemic activity in preclinical studies. We have examined the effect of this agent on the metabolism and cytotoxicity of 1-beta-D-arabinofuranosylcytosine (ara-C) in both log phase and high-density human promyelocytic leukemia cells (HL-60). Exposure of low-density cells to 12.5 nM bryostatin 1 for 24 hr prior to a 4-hr incubation with 1 or 10 microM ara-C resulted in nearly a 2-fold increase in ara-CTP formation. When cells were maintained under high-cell density conditions (e.g. 5 x 10(6) cells/mL) for 24 hr prior to ara-C exposure, a 90% reduction in ara-CTP formation and ara-C DNA incorporation was observed. However, coincubation of high-density cells with bryostatin 1 for 24 hr increased ara-CTP formation 6- to 8-fold, yielding levels essentially equivalent to those achieved in low-density cells. Smaller (but still significant) increases in ara-C DNA incorporation were also noted. Enhancement of ara-CTP formation by bryostatin 1 occurred over a broad ara-C concentration range (0.1 to 100 microM), involved a temperature-dependent process, could not be mimicked by addition of hematopoietic growth factors, and was not related to neutralization of toxic or inhibitory substances in high-density medium. Exposure of cells to bryostatin 1 did not lead to morphologic or functional evidence of HL-60 cell maturation or an increase in cell viability, but did produce a decline in cellular proliferative activity as determined by thymidine and bromodeoxyuridine incorporation and cytofluorometric analysis. Bryostatin 1 did not exert its effects in high-density cells by inhibiting ara-C deamination or by interfering with ara-CTP dephosphorylation, but instead appeared to act by enhancing ara-C phosphorylation. Although cell-free extracts obtained from high-density cells exposed to bryostatin 1 exhibited levels of deoxycytidine kinase activity compared to controls, treated cells did display a significant decline in intracellular dCTP levels (e.g. 0.7 vs 1.3 pmol/10(6)), and nearly a 2-fold increase in ATP and UTP concentrations. Ara-CTP formation was also increased substantially by other PK-C activators including phorbol dibutyrate and mezerein (10-100 nM); this process was inhibited more than 70% by the PK-C inhibitor H-7 (50 microM), but not by the PK-C inhibitors staurosporine, tamoxifen, and HA1004. Finally, coadministration of ara-C and bryostatin 1 resulted in greater than expected inhibitory effects toward HL-60 cell clonogenic growth.(ABSTRACT TRUNCATED AT 400 WORDS)     

Studies of phosphorylation in rat mast cells (third report)--isolation of calcium-activated, phospholipid, diacylglycerol-dependent protein kinase from rat basophilic leukemia cells (RBL-1 cells)

Evidence is presented that RBL-1 cells, which are similar to normal rat mast cells in morphology and contain IgE receptors and histamine, contain a calcium-activated, phospholipid, diacylglycerol-dependent protein kinase. This enzyme is very similar in its activation requirements to the calcium-dependent enzyme termed protein kinase C in other tissues. The enzyme is activated by Ca2+. Diolein, but not other di, mono or triglycerides, substantially increases the enzyme activity. Among various phospholipids, phosphatidylserine is the most reactive activator; phosphatidylinositol, phosphatidic acid and phosphatidylethanolamine are less effective; and phosphatidylcholine is practically inactive. The enzyme is inhibited by chlorpromazine and local anesthetics such as dibucaine, tetracaine and procaine.     

In vitro inhibition of human liver cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT) enzymes by rose bengal: system-dependent effects on inhibitory potential

Abstract

1. Rose bengal (4,5,6,7-tetrachloro-2′,4′,5′,7′-tetraiodofluorescein) is being developed for the treatment of cutaneous melanoma and hepatocellular carcinoma. Interestingly, rose bengal can generate singlet oxygen species upon exposure to light.

2. We evaluated rose bengal as an in vitro inhibitor of cytochrome P450 (CYP) or UDP-glucuronosyltransferase (UGT) enzymes in both human liver microsomes (HLM) and cryopreserved human hepatocytes (CHHs) under both yellow light and dark conditions.

3. Rose bengal directly inhibited CYP3A4/5 and UGT1A6 in HLM under yellow light with inhibitor concentration that causes 50% inhibition (IC₅₀) values of 0.072 and 0.035?μM, respectively; whereas much less inhibition was observed in the dark with the IC₅₀ values increasing 43- and 120-fold, respectively. To determine if a more physiologically-relevant test system could be protected from such an effect, rose bengal was evaluated as an inhibitor of CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, 3A4/5 and UGT enzymes in CHH. All IC₅₀ values were similar (64?±?8?μM) and little to no effect of light on inhibitory potential was observed.

4. Given the IC₅₀ values in CHH increased an order of magnitude compared to HLM and the atypical pharmacokinetics of the drug, the risk of rose bengal to cause clinically relevant drug–drug interactions is likely low, particularly when administered to cancer patients on an intermittent schedule.