靶向鞘氨醇激酶信号通路:一种治疗血液肿瘤的新策略（英文）

1-磷酸鞘氨醇(S1P)是重要的磷脂代谢产物并介导广泛的生物学效应,包括细胞增殖、存活和迁移等。S1P在细胞内由鞘氨醇激酶(SphK)使鞘氨醇磷酸化而形成。S1P代谢的异常调节已经成为血液肿瘤发生发展的重要环节。利用抑制剂、激动剂及抗体等靶向SphK-S1P信号通路(包括S1P受体及参与合成和降解的关键酶)已经成为血液肿瘤的新治疗策略。本文综述了SphK-S1P的重要生理作用,重点阐述了其异常调节机制及其靶向治疗在血液肿瘤中病理生理过程中的重要性。首先对磷脂代谢和信号调控进行了概述,然后总结了S1P的合成、代谢、病理和生理作用、异常调节机制以及在血液肿瘤中靶向策略。另外,还讨论了靶向SphK信号通路在新药研发中的前景和重要性。     

1-磷酸鞘氨醇及其信号通路在炎症相关性疾病中的作用

1-磷酸鞘氨醇(sphingosine 1-phosphate,S1P)是细胞膜鞘磷脂在代谢过程中产生的一类重要的信号分子,S1P可被转运到细胞外,通过作用于S1P受体,激活一系列下游信号分子发挥作用,如Ras/Raf/ERK、PI3K/Akt等,也可作为第二信使直接作用于细胞内靶点,如HDAC、TRAF2。其介导的信号通路在很多生理和病理过程中发挥作用,如细胞增殖和迁移、炎性细胞因子浸润、血管生成、自身免疫等。该文分别从S1P的胞外及胞内两种作用方式,探讨S1P及其信号通路在炎症相关性疾病中的作用,综述S1P信号通路相关药物研究进展。     

1-磷酸鞘氨醇及受体对自身免疫性疾病血管新生的影响

1-磷酸鞘氨醇(sphingosine-1-phosphate,S1P)是细胞膜鞘磷脂代谢过程产生的一类信号分子,在免疫系统中,与细胞膜表面的G蛋白偶联受体S1P受体(S1P receptors,S1PRs)结合,通过相关炎症信号通路,影响新生血管的形成。该文简述S1P及其受体通过细胞内信号转导对类风湿关节炎、多发性硬化症、结肠炎、系统性红斑狼疮等自身免疫性疾病微血管生成的影响,提出了S1P及其受体可能是治疗自身免疫性疾病血管炎症新的靶点。     

鞘氨醇激酶和1-磷酸鞘氨醇及其受体信号在肿瘤微环境中的研究进展

鞘氨醇激酶(SphK)、1-磷酸鞘氨醇(S1P)及其受体(S1PR)参与肿瘤细胞增殖、迁移等生物学过程,在癌症的发生发展中起重要作用。近年来,研究者日益关注癌细胞与肿瘤微环境之间的相互作用,肿瘤微环境具有遗传稳定性并且能够被诱导为抗肿瘤表型,具有显著的治疗优势。研究显示, SphK/S1P/S1PR能够调节肿瘤微环境的多个方面。本文从肿瘤免疫微环境、癌症相关成纤维细胞、肿瘤血管生成、肿瘤缺氧微环境4个角度对SphK和S1P/S1PR信号对肿瘤微环境的影响进行综述,并简要概述相关药物研究情况,旨在阐明SphK/S1P/S1PR在癌症中的作用及为抗肿瘤药物的研究提供新思路。     

少动鞘氨醇单胞菌致菌血症伴阑尾炎患者1例

通过1例少动鞘氨醇单胞菌(Sphingomonas paucimobilis)致菌血症伴阑尾炎患者,分析了少动鞘氨醇单胞菌所致菌血症伴阑尾炎的因果关系和治疗措施。     

鞘氨醇激酶在胃癌中的研究进展

鞘氨醇激酶(SphK)是鞘脂代谢酶,已发现有SphKl和SphK2两种异构体。SphK1在包括胃癌在内的多肿瘤中表达增加,能促进肿瘤细胞的增殖、侵袭和转移,并参与了肿瘤血管的形成,而且可能在肿瘤化疗耐药中起重要作用。目前,针对SphK2的研究结果虽不一致,但多偏向于SphK2促进肿瘤细胞增殖并抑制凋亡,也参与肿瘤的发生和发展。调控SphK有望成为包括胃癌在内的肿瘤治疗的新靶点。     

鞘氨醇激酶1抑制剂和5-FU联合应用对体外胃癌细胞增殖与凋亡的影响

目的观察鞘氨醇激酶1(SphK1)抑制剂二甲基鞘氨醇(DMS)与化疗药物5-氟尿嘧啶(5-FU)联合应用对体外胃癌细胞SGC7901增殖与凋亡的影响。方法体外培养人胃癌细胞株SGC7901,分别单用不同浓度5-FU(1、5、25μg/ml)或5-FU与DMS(1μmol/L)联合应用。MTT比色法检测各组细胞生长抑制率,光镜下观察细胞形态变化,流式细胞术检测各组细胞凋亡率。通过SAS软件进行反应曲面分析,分析两药之间的关系。结果不同浓度的5-FU单用组及联用DMS组的抑制率差异有统计学意义(P<0.05),联用组抑制率均高于单用组,两者具有协同作用。单用DMS组及5-FU组的胃癌细胞凋亡率较空白对照组明显增高,联用组凋亡率较单用组明显增加(P<0.05)。结论 DMS可抑制SGC7901细胞的增殖;DMS和5-FU联用显示了较好的协同作用,提示抑制SphK1活性能够提高胃癌细胞对于化疗药物的敏感性。     

鞘氨醇-1-磷酸受体1在疼痛中的作用研究

鞘氨醇-1-磷酸受体1(sphingosine-1-phosphate receptor1,S1PR1)属于G蛋白偶联受体,其能调节多种下游信号分子和细胞功能。研究发现S1PR1在疼痛中发挥重要作用,但激活S1PR1产生致痛作用还是镇痛作用尚存在争议。该文讨论了S1P/S1PR1信号在疼痛研究中的最新观点与进展,以增进对其生物学功能及病理作用的了解。     

SPHK1在甲状腺乳头状癌中的表达及其对IHH4细胞侵袭和迁移的影响

目的 探讨鞘氨醇激酶1(SPHK1)在甲状腺乳头状癌(PTC)中的表达及对IHH4细胞侵袭和迁移的影响.方法 采用免疫组化检测110例PTC组织及癌旁组织中SPHK1的表达,分析SPHK1表达与其临床指标的关系.采用小于扰RNA-SPHK1转染PTC细胞系IHH4,Transwell实验和细胞划痕实验分析其对IHH4细...     

胡黄连苷Ⅱ对非小细胞肺癌恶性进展的影响

目的 探讨胡黄连苷Ⅱ对非小细胞肺癌（NSCLC）恶性进展的影响及机制。方法 将A549细胞分组为对照组,胡黄连苷Ⅱ低、中、高浓度组,K6PC-5[鞘氨醇激酶1(SPHK1)激活剂]组,胡黄连苷Ⅱ高剂量+K6PC-5组,检测细胞增殖、迁移、侵袭情况,以及细胞中增殖细胞核抗原（PCNA）、基质金属蛋白酶2(MMP-2)、MMP-9、SPHK1、1-磷酸鞘氨醇受体3(S1PR3)及胞外信号调节激酶1/2(ERK1/2)蛋白的表达情况。以BALB/c裸鼠为对象,通过皮下接种A549细胞悬液建立NSCLC裸鼠移植瘤模型,并将其分为裸鼠-对照组,裸鼠-胡黄连苷Ⅱ低、中、高剂量组,裸鼠-K6PC-5组,裸鼠-胡黄连苷Ⅱ高剂量+K6PC-5组（每组5只）,考察胡黄连苷Ⅱ对其瘤体质量及体积的影响。结果 与对照组比较,胡黄连苷Ⅱ低、中、高浓度组的细胞OD450值、EdU阳性细胞率、划痕愈合率、细胞侵袭数及PCNA、MMP-2、MMP-9、SPHK1、S1PR3、ERK1/2蛋白的相对表达量均显著降低;与裸鼠-对照组比较,裸鼠-胡黄连苷Ⅱ低、中、高剂量组裸鼠体内的瘤体质量及体积均显著降低或缩小,上述指标均呈...     

Ceramide formation as a target in beta-cell survival and function

INTRODUCTION: Ceramide may be synthesized de novo or generated by sphingomyelinase-dependent hydrolysis of sphingomyelin. AREAS COVERED: The role of ceramide, ceramide-sensitive signaling and ion channels in β-cell apoptosis, lipotoxicity and amyloid-induced β-cell death. EXPERT OPINION: Ceramide participates in β-cell dysfunction and apoptosis after exposure to TNFα, IL-1β and IFN-γ, excessive amyloid and islet amyloid polypeptide or non-esterified fatty acids (lipotoxicity). Knockout of sphingomyelin synthase 1, which converts ceramide to sphingomyelin, leads to impairment of insulin secretion. Increased ceramidase activity or pharmacological inhibition of ceramide synthetase, inhibits β-cell apoptosis. Ceramide contributes to endoplasmatic reticulum (ER) stress, decreased mitochondrial membrane potential in insulin-secreting cells and mitochondrial release of cytochrome c into the cytosol, which are all triggers of apoptotic cell death. Ceramide-dependent signaling involves activation of extracellularly regulated kinases 1 and 2 (ERK1/2), downregulation of Period (Per)-aryl hydrocarbon receptor nuclear translocator (Arnt)-single-minded (Sim) kinase (PASK), activation of okadaic-acid-sensitive protein phosphatase 2A (PP2A) and stimulation of NADPH-oxidase with generation of superoxides and lipid peroxides. Ceramide reduces the activity of voltage gated potassium (Kv)-channels in insulin-secreting cells. The role of ceramide in β-cell survival and function may be therapeutically relevant, because ceramide formation can be suppressed by pharmacological inhibition of ceramide synthetase and/or sphingomyelinase.     

Curcumin decreases acid sphingomyelinase activity in colon cancer Caco-2 cells

Curcumin has been shown to inhibit cell growth and induce apoptosis in colon cancer cells. The metabolism of sphingomyelin has implications in the development of colon cancert. We examined whether curcumin affects the enzymes that hydrolyse sphingomyelin in Caco-2 cells. The cells were cultured in both monolayer and polarized conditions and stimulated with curcumin. The activities of sphingomyelinases were determined. Sphingomyelin and its hydrolytic products were analysed by thin layer chromatography. The changes of acid sphingomyelinase protein were examined by Western blotting. We found that curcumin reduced the hydrolytic capacity of the cells against choline-labelled sphingomyelin, associated with a mild increase of cellular sphingomyelin in the cells. Analysis of the hydrolytic products revealed that the activity was derived from acid sphingomyelinase not from phospholipase D. The curcumin-induced reduction of acid SMase required more than 8 h stimulation. Western blotting showed reduced acid sphingomyelinase protein after curcumin stimulation. The inhibitory effect was more potent in monolayer cells than in polarised cells. No changes of other sphingomyelinases were identified. In the concentrations inhibiting acid sphingomyelinase, curcumin inhibited DNA synthesis and induced cell death. In conclusion, curcumin inhibits acid sphingomyelinase and the effect might be involved in its antiproliferative property against colon cancer cells.     

Alteration of ceramide 1-O-functionalization as a promising approach for cancer therapy

Sphingolipids, which are complex lipidic components of the cell membranes, lie in a key position to modulate the pathways of trans-membrane signaling and allow the cell to adapt to environmental stresses. In malignancies, reduced production of some sphingolipid species able to induce apoptosis such as ceramide and conversely, increased levels of some other metabolites involved in tumor progression and drug resistance of cancer cells, are often described. In this context, the discovery of new chemical entities able to specifically modify ceramide metabolism should offer novel pharmacological tools in cancer therapy. The review dedicates particular attention to the enzymes that modify ceramide at the C1-OH position generating other biologically important sphingolipids in cancer, such as sphingomyelin, ceramide-1-phosphate or glucosylceramide. Findings reported in the literature leading to the development of new chemical entities specifically designed to achieve the above goals have been collected and are discussed. The effects of enzyme inhibitors of sphingomyelin synthase, ceramide kinase and glucosylceramide synthase on cancer cell proliferation, sensitivity to chemotherapeutics, induction of apoptosis or growth of xenografts are presented.     

姜黄素抗肿瘤作用机制的研究进展

多种恶性肿瘤细胞中表达细胞凋亡抑制蛋白（IAPs）,如：Survivin、NAIP、XIAP、Livin等,同样表达抗细胞凋亡Bcl-2家族蛋白。IAPS介导的凋亡抑制可能是肿瘤细胞耐药而存活的原因之一;Bcl-2家族蛋白在抗肿瘤凋亡及促其凋亡中发挥作用。姜黄素具有抗炎、抗氧化、抑制血管新生等,可以通过调控蛋白表达及相关信号通路促进细胞凋亡、抗肿瘤作用。     

Sticholysin II: A pore-forming toxin as a probe to recognize sphingomyelin in artificial and cellular membranes

Sphingomyelin is a major component of membrane rafts, and also is a precursor of many bioactive molecules. The sphingomyelin plays important biological roles and alterations of its metabolism are the basis of some genetic disorders such as the Niemann Pick disease. A complete understanding of its biological role is frustrated by the lack of efficient tools for its recognition in the cell. Sticholysin II (StnII) is a 20 kDa protein from the sea-anemone Stichodactyla helianthus which shows a cytotoxic activity by forming oligomeric aqueous pores in the cell plasma membrane. A recent NMR analysis indicates that the sticholysin II binds specifically to sphingomyelin by two domains that recognize respectively the hydrophilic (i.e. phosphorylcholine) and the hydrophobic (i.e. ceramide) moieties of the molecule. Aim of our research has been to verify the possible employ of an antibody against the StnII to investigate the localization and the dynamics of sphingomyelin in cell membranes. For this purpose, we developed a monoclonal antibody (named A10) against the toxin and we tested its ability to bind StnII after binding to sphingomyelin. A10 antibody is able to recognize the sticholysin II both in its native form and after SDS treatment, being the protein still suitable for many analytic techniques such as ELISA, western blotting and immunofluorescence. The high affinity of the toxin for the sphingomyelin in cell membranes has been demonstrated by microscopic immuno-localization and western blot analysis; both methods confirmed that sphingomyelin is the molecular acceptor for StnII also in cell membranes. Finally, we studied the specificity of the toxin for sphingomyelin by a cell membrane-double labelling method, using cholera toxin, specific for the ganglioside GM1, and sticholysin II. The results obtained show that there is no cross-reactivity between the two toxins, confirming that sticholysin II is able to discriminate among membrane domains with sphingomyelin with respect to those enriched with gangliosides.     

Ceramide formation as a target in beta-cell survival and function

Introduction: Ceramide may be synthesized de novo or generated by sphingomyelinase-dependent hydrolysis of sphingomyelin.

Areas covered: The role of ceramide, ceramide-sensitive signaling and ion channels in β-cell apoptosis, lipotoxicity and amyloid-induced β-cell death.

Expert opinion: Ceramide participates in β-cell dysfunction and apoptosis after exposure to TNFα, IL-1β and IFN-γ, excessive amyloid and islet amyloid polypeptide or non-esterified fatty acids (lipotoxicity). Knockout of sphingomyelin synthase 1, which converts ceramide to sphingomyelin, leads to impairment of insulin secretion. Increased ceramidase activity or pharmacological inhibition of ceramide synthetase, inhibits β-cell apoptosis. Ceramide contributes to endoplasmatic reticulum (ER) stress, decreased mitochondrial membrane potential in insulin-secreting cells and mitochondrial release of cytochrome c into the cytosol, which are all triggers of apoptotic cell death. Ceramide-dependent signaling involves activation of extracellularly regulated kinases 1 and 2 (ERK1/2), downregulation of Period (Per)-aryl hydrocarbon receptor nuclear translocator (Arnt)-single-minded (Sim) kinase (PASK), activation of okadaic-acid-sensitive protein phosphatase 2A (PP2A) and stimulation of NADPH-oxidase with generation of superoxides and lipid peroxides. Ceramide reduces the activity of voltage gated potassium (Kv)-channels in insulin-secreting cells. The role of ceramide in β-cell survival and function may be therapeutically relevant, because ceramide formation can be suppressed by pharmacological inhibition of ceramide synthetase and/or sphingomyelinase.     

"Ecstasy"-induced toxicity in SH-SY5Y differentiated cells: role of hyperthermia and metabolites

3,4-Methylenedioxymethamphetamine (MDMA; “ecstasy”) is a recreational hallucinogenic drug of abuse known to elicit neurotoxic properties. Hepatic formation of neurotoxic metabolites is thought to play a major role in MDMA-related neurotoxicity, though the mechanisms involved are still unclear. Here, we studied the neurotoxicity mechanisms and stability of MDMA and 6 of its major human metabolites, namely α-methyldopamine (α-MeDA) and N-methyl-α-methyldopamine (N-Me-α-MeDA) and their correspondent glutathione (GSH) and N-acetyl-cysteine (NAC) conjugates, under normothermic (37 °C) or hyperthermic conditions (40 °C), using cultured SH-SY5Y differentiated cells. We showed that MDMA metabolites exhibited toxicity to SH-SY5Y differentiated cells, being the GSH and NAC conjugates more toxic than their catecholic precursors and MDMA. Furthermore, whereas the toxicity of the catechol metabolites was potentiated by hyperthermia, NAC-conjugated metabolites revealed higher toxicity under normothermia and GSH-conjugated metabolites-induced toxicity was temperature-independent. Moreover, a time-dependent decrease in extracellular concentration of MDMA metabolites was observed, which was potentiated by hyperthermia. The antioxidant NAC significantly protected against the neurotoxic effects of MDMA metabolites. MDMA metabolites increased intracellular glutathione levels, though depletion in thiol content was observed in MDMA-exposed cells. Finally, the neurotoxic effects induced by the MDMA metabolite N-Me-α-MeDA involved caspase 3 activation. In conclusion, this study evaluated the stability of MDMA metabolites in vitro, and demonstrated that the catechol MDMA metabolites and their GSH and NAC conjugates, rather than MDMA itself, exhibited neurotoxic actions in SH-SY5Y differentiated cells, which were differently affected by hyperthermia, thus highlighting a major role for reactive metabolites and hyperthermia in MDMA’s neurotoxicity.     

Signal transduction mechanisms for the survival and death of neurons and muscle cells: modulation by membrane lipid rafts and their abnormality in the disorders of the nervous system]

Recent advances have accumulated evidence that membrane lipid rafts or caveola play an essential role in cell-cell communications and signal transduction across membranes. The main constituents of lipid rafts include cholesterol, sphingomyelin, and glycosphingolipids such GM1 ganglioside. Many receptor-type tyrosine kinases and GPI-anchored proteins are now known to be the residents of lipid rafts. Therefore, it has been postulated that there are some direct or indirect interactions between these signaling molecules and lipids within lipid rafts, but no definite evidence has been available. In this study, we explored the molecular interactions of receptor-type tyrosine kinase, Trk, which essential for the neuronal survival and differentiation and for lipids, especially gangliosides. We also examined how the chemical depletion of another main lipid, cholesterol, affects the cellular function of muscle cells and its outcome. The data clearly indicate that 1) chemical and genetical depletion of gangliosides resulted in the impairment of the Trk-dependent protein kinase cascade. 2) depletion of intracellular cholesterol induced tyrosine phosphorylations of several cellular proteins including the p110 catalytic subunit of phosphatidylinositol-3 kinase and phospholipase C-gamma and the destruction of lipid rafts resulting in the development of apoptotic cell death of muscle cells.     

Anti-androgen-independent prostate cancer effects of ginsenoside metabolites <Emphasis Type="Italic">In Vitro</Emphasis>: Mechanism and possible structure-activity relationship investigation

Treatment of androgen-independent prostate cancer (AIPC) remains unsatisfactory. In our present experiment, natural occurring ginsenosides (NOGs) and intestinal bacterial metabolites (IBMs) were employed to investigate their anti-AIPC cell growth activity using PC-3 cells. Our results showed that the IBMs exerted more portent anti-AIPC activity than NOGs, by decreasing survival rate, inhibiting proliferation, inducing apoptosis, and leading to cell cycle arrest in AIPC PC-3 cells. The increase of LogP and decrease of C-6 steric hindrance, which were caused by deglycosylation by intestinal bacteria, may be the reason for the higher anti-AIPC activity of IBMs.     

Embryonic stem cell application in drug discovery

Embryonic stem (ES) cells and their differentiated progeny offer tremendous potential for regenerative medicine, even in the field of drug discovery. There is an urgent need for clinically relevant assays that make use of ES cells because of their rich biological utility. Attention has been focused on small molecules that allow the precise manipulation of cells in vitro, which could allow researchers to obtain homogeneous cell types for cell-based therapies and discover drugs for stimulating the regeneration of endogenous cells. Such therapeutics can act on target cells or their niches in vivo to promote cell survival, proliferation, differentiation, and homing. In the present paper, we reviewed the use of ES cell models for high-throughput/content drug screening and toxicity assessment. In addition, we examined the role of stem cells in large pharmaceutical companies' R&D and discussed a novel subject, nicheology, in stem cell-related research fields.