Shikonin from Chinese herbal medicine induces GSDME-controlled pyroptosis in tumor cells

ObjectiveTo investigate the potential anti-tumor mechanisms of naphthoquinone compound shikonin (SKN) extracted from the root of Chinese herbal medicine plant lithospermum (Lithospermum erythrorhizon Sieb. & Zucc.).MethodsWe first observed that SKN treatment led to swelling and bubbles in HeLa cells that were similar to the phenotype of cell pyroptosis. Subsequently, the HeLa cells experienced a pyroptotic process with SKN, and this was then assessed using lactate dehydrogenase (LDH) release and propidium iodide (PI)/Hoechst double staining experiments. Pyroptosis is defined as gasdermin-mediated programmed necroptosis. To identify the potential pyroptosis machinery, two strategies were utilized that included a genome-wide clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 screening experiment and a pyroptosis reconstitution assay executed by each of the five known gasdermins (GSDMA-E). Moreover, endogenous cleavage was also detected in a panel of tumor cell lines.ResultsCompared with the control, both the LDH release and PI/Hoechst double-staining experiments suggested that SKN induced perforation and enhancement of the permeability of the cell membranes that resulted in pyroptosis in HeLa cells (P = .028 and P = .032, respectively). In addition, the reconstitution assays in human embryonic kidney 293T (HEK-293T) cells and endogenous cleavage assays in HeLa cells indicated that the pyroptosis was controlled by GSDME. In addition, we also found SKN could trigger pyroptosis in a panel of tumor cell lines in which the cellular morphologies were proportional to the GSDME expression levels. Additionally, the cleavage of GSDME was also detected, and this was indicative of a similar GSDME-mediated mechanism.ConclusionOur study not only explained the molecular mechanism of cytotoxicity of SKN to various tumor cells, but also provided additional information for the potential clinical application of natural naphthoquinone compounds against cancer.     

紫草素对高糖诱导的血管内皮细胞凋亡和氧化应激的影响

目的:探讨紫草素(shikonin)对高浓度葡萄糖诱导的血管内皮细胞凋亡和氧化应激水平的影响及其可能的作用机制。方法:体外培养的大鼠胸主动脉内皮细胞随机分为5组:正常对照组(培养基中葡萄糖浓度为5.5 mmol/L)、高糖组(培养基中葡萄糖浓度为33 mmol/L)、高糖+低浓度紫草素组(培养基中葡萄糖浓度为33mmol/L,紫草素浓度为0.1μmol/L)、高糖+中浓度紫草素组(培养基中葡萄糖浓度为33 mmol/L,紫草素浓度为1μmol/L)和高糖+高浓度紫草素组(培养基中葡萄糖浓度为33 mmol/L,紫草素浓度为10μmol/L)。各组细胞经相应处理后,CCK-8法检测细胞活力,流式细胞术检测细胞的凋亡率;此外,检测细胞中丙二醛(malondialdehyde,MDA)、活性氧簇(reactive oxygen species,ROS)、超氧化物歧化酶(superoxide dismutase,SOD)及谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)的水平,以反映细胞的氧化应激状态;Western blot检测Nrf2/HO-1信号通路的活性。结果:相较于高糖组,紫草素处理可呈剂量依赖性地逆转高糖所致的内皮细胞活力降低及凋亡率增加。与正常对照组相比,高浓度葡萄糖可升高内皮细胞中MDA和ROS的含量,同时降低SOD和GSH-Px的活性;相较于高糖组,给予紫草素干预后,细胞内MDA和ROS的含量降低,SOD和GSH-Px的活性升高。此外,高糖可致内皮细胞中cleaved caspase-3、HO-1及核内Nrf2蛋白表达的增加;与高糖组相比,给予紫草素干预后细胞中cleaved caspase-3、HO-1和核内Nrf2的表达部分下降。结论:紫草素可显著改善高糖所致的血管内皮细胞凋亡,其作用机制可能与激活Nrf2/HO-1信号通路并降低细胞的氧化应激水平有关。     

紫草素对HGF诱导的人肺癌细胞上皮-间充质转化的逆转作用

目的:探讨紫草素(shikonin)对肝细胞生长因子(HGF)诱导的人非小细胞肺癌PC9细胞迁移、侵袭及上皮-间充质转化(EMT)的影响。方法:用HGF诱导PC9细胞建立EMT模型,采用不同剂量的shikonin干预24 h后,MTT法检测细胞活力;划痕愈合实验检测细胞的迁移能力;Transwell小室实验检测细胞的侵袭能力;Western blot法检测细胞中上皮型钙黏蛋白(E-cadherin)、神经型钙黏蛋白(N-cadherin)和波形蛋白(vimentin)的蛋白表达水平。结果:Shikonin可显著抑制PC9细胞的活力(P0.01),随着给药剂量的增加,shikonin对细胞的生长抑制率显著上升,并呈一定的剂量依赖关系,IC_(50)为9.364μmol/L。HGF可诱导PC9细胞发生迁移和侵袭;划痕愈合实验和Transwell小室实验显示,shikonin能明显抑制由HGF诱导的肺癌PC9细胞迁移和侵袭(P0.01)。Western blot检测结果显示HGF可诱导PC9细胞的EMT标志物E-cadherin蛋白表达下调,N-cadherin和vimentin蛋白表达上调,使其发生EMT;shikonin则可逆转由HGF诱导的PC9细胞E-cadherin蛋白表达下调及N-cadherin和vimentin蛋白表达上调(P0.01)。结论:Shikonin能逆转由HGF诱导的肺癌PC9细胞EMT,同时抑制其迁移和侵袭。     

The Inhibitory Effect of Shikonin on the Agonist-Induced Regulation of Vascular Contractility

Shikonin, a natural flavonoid found in the roots of Lithospermum erythrorhizon, has been shown to possess many biological functions. The present study was undertaken to investigate the influence of shikonin on vascular smooth muscle contractility and to determine the mechanism involved. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Shikonin significantly relaxed fluoride-, thromboxane A₂- or phorbol ester-induced vascular contraction suggesting as a possible anti-hypertensive on the agonist-induced vascular contraction regardless of endothelial nitric oxide synthesis. Furthermore, shikonin significantly inhibited fluoride-induced increases in pMYPT1 levels and phorbol ester-induced increases in pERK1/2 levels suggesting the mechanism involving the inhibition of Rho-kinase activity and the subsequent phosphorylation of MYPT1 and the inhibition of MEK activity and the subsequent phosphorylation of ERK1/2. This study provides evidence regarding the mechanism underlying the relaxation effect of shikonin on agonist-induced vascular contraction regardless of endothelial function.     

Shikonin ameliorates D-galactose-induced oxidative stress and cognitive impairment in mice via the MAPK and nuclear factor-κB signaling pathway

Oxidative stress acts as the major causative factor for various age‐associated neurodegenerative diseases, triggering cognitive and memory impairments. In the present study, the underlying neuroprotective mechanism governing how shikonin acts against D-galactose (D-gal)-induced memory impairment, neuroinflammation and neuron damage was examined. The results revealed that chronic administration of D-gal [150 mg/kg intraperitoneally (i.p.)] in mice caused cognitive and memory impairments, as determined by Morris water-maze test. Shikonin treatment, however, alleviated D‐gal-induced memory impairment and reversed the D‐gal-induced neural damage and apoptosis. Furthermore, western blotting and the results of morphological analysis revealed that shikonin treatments markedly reduced D‐gal induced neuroinflammation through inhibition of astrocytosis as determined by glial fibrillary acidic protein (GFAP) detection, and downregulating other inflammatory mediators, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6. Moreover, shikonin treatment led to inhibition of the activation of nuclear factor‐κB (NF‐κB) and the phosphorylation of mitogen-activated protein kinases (MAPKs), preventing neurodegeneration. Hence, taken together, the results of the present study suggested that shikonin attenuated D‐gal-induced memory impairment, neuroinflammation and neurodegeneration, possibly via the NF‐κB/mitogen-activated protein kinase (MAPK) pathway. Our data suggest that shikonin could be a promising, endogenous and compatible antioxidant candidate for age‐associated neurodegenerative diseases, including Alzheimer's disease.     

Enhancement of NK cells proliferation and function by Shikonin

Context: Shikonin is a kind of naphthoquinone compound found mainly in Lithospermum erythrorhizon Sieb,et Zucc. Previous studies have shown that Shikonin has anti-tumor, anti-inflammatory and extensive pharmacological effects. According to new studies, Shikonin could also modulate the immune system function, but the effect to NK (nature killer) cells is yet unknown.

Objective: To investigate the effect and mechanism of Shikonin on NK cells proliferation and cytotoxicity to colon cancer cell line (Caco-2).

Methods: The proliferation and cytotoxicity of NK cells cultured with Shikonin were detected with CCK-8 assay. The expressions of perforin, GranB and IFN-γ were examined with FCM. The content of TNF-alpha was disclosed with ELISA kit. p-ERK1/2 and p-Akt expression of NK cells were detected with western blot.

Results: With CCK-8 assay, it is found that Shikonin could significantly enhance NK cells proliferation and cytotoxicity to colon cancer cells. With FCM assay, it is found that Shikonin could improve the expression of perforin and GranB in a dose-dependent manner. Shikonin had no effect on TNF-alpha and IFN-γ expression. In mechanism, the study shows that Shikonin could enhance the expression of p-ERK1/2 and p-Akt.

Conclusions: Shikonin enhances NK cells proliferation and cytotoxicity via the improvement of perforin, GranB, p-ERK1/2 and p-Akt expression.     

Shikonin protects chondrocytes from interleukin-1beta-induced apoptosis by regulating PI3K/Akt signaling pathway

Chondrocyte apoptosis is mostly responsible for the development and progression of osteoarthritis. IL-1β is generally served as an agent that induces chondrocyte apoptosis. Shikonin exerts its anti-inflammatory effect on cartilage protection in vivo. We aimed to explore the protective effect of shikonin on interleukin-1beta (IL-1β)-induced chondrocyte apoptosis and the potential molecular mechanisms. Chondrocytes were isolated from the joints of newborn Sprague-Dawley rats. The MTT assay and LDH cell death assay were used to determine the cell viability and chondrocyte apoptosis was detected by Annexin-V/PI staining and nucleosomal degradation. The contents of phosphorylated-PI3K (p-PI3k), phosphorylated-Akt (p-Akt), Bcl-2, Bax, and cytochrome c were detected by Western blotting. A quantitative colorimetric assay was used to detect the caspase-3 activity. Our results showed that pretreatment with shikonin (4 μM) inhibited cytotoxicity and apoptosis induced by IL-1β (10 ng/ml) in chondrocytes. Shikonin pretreatment also decreased the activity of IL-1β that decreased Bcl-2 expression and levels of p-PI3K and p-Akt, and increased Bax expression, cytochrome c release, and caspase-3 activation. It also reversed the activity of IL-1β that promoted the synthesis of matrix metalloproteinase-13 and inhibited the expression of tissue inhibitor of metalloproteinase-1 expression, with the net effect of suppressing extracellular matrix degradation. These data suggested that shikonin may protect chondrocytes from apoptosis induced by IL-1β through the PI3K/Akt signaling pathway, by deactivating caspase-3.     

紫草及紫草制剂的抗炎作用研究进展

目的:为紫草和紫草制剂的抗炎机制研究及产品开发提供参考。方法:以"紫草""紫草素""制剂""抗炎""进展""zicao""shikonin""anti-inflammatory"等为关键词,在Pub Med、CNKI等多个数据库中查询建库至2017年12月31日的相关文献,对紫草、紫草素和紫草复方制剂抗炎作用的相关研究进行综述。结果与结论:共检索到相关文献128篇,其中有效文献41篇。紫草以新疆软紫草品质最佳,而滇紫草、泰山紫草等也被逐步肯定。紫草醇提物抗炎效果最优,紫草素及其衍生物的抗炎活性突出。紫草、紫草素及紫草复方制剂治疗烧烫伤、湿疹、银屑病、过敏性紫癜、关节炎、静脉炎、妇科炎症、急性肺损伤、重症急性胰腺炎伴肺损伤或肝损伤、局部脑缺血等多种疾病的实验研究正逐步深入,多认为其抗炎机制与NF-κB、IL-1β、IL-6、TNF-α、NO、CCR、COX-2、IL-22、IL-17等密切相关。紫草及紫草制剂现已广泛用于临床治疗湿疹、皮炎、妇科炎症、皮肤创面及黏膜损伤等多种炎症性疾病,其剂型多为油剂、膏剂、栓剂、喷雾剂等。如何高效发挥紫草及紫草制剂的抗炎作用,尚有待在微观层面运用生物组学技术等继续深入研究。     

紫草素对口腔鳞癌Tca8113细胞增殖与凋亡的作用

目的：研究紫草素对体外培养的口腔鳞癌Tca8113细胞的增殖抑制及诱导凋亡作用。方法：采用四甲基偶氮唑蓝（MTT）法观察紫草素对Tca8113细胞的体外增殖抑制作用;采用光镜、透射电镜、琼脂糖凝胶电泳技术及流式细胞术观察紫草素对Tca8113细胞凋亡的影响。采用SPSS12．0软件包对数据进行单因素方差分析及t检验。结果：MTr检测显示．紫草素在0-50μmol／L浓度范围内。对Tca8113细胞的增殖抑制作用呈现时间依赖性和浓度依赖性（P〈0．01）．电镜下可见典型的细胞核皱缩及凋亡小体,DNA琼脂糖凝胶电泳观察到典型梯状条带,流式细胞仪结果显示亚G1期细胞明显增加,各组细胞凋亡率均显著高于对照组（P〈0．01）。结论：紫草素对口腔鳞癌Tca8113细胞具有明显的增殖抑制及诱导凋亡作用．可用于口腔鳞癌化学防治的新尝试。     

紫草素对NZB／WF1小鼠狼疮性肾炎的疗效及其作用机制

目的探讨紫草素对NZB／WF1狼疮样小鼠的疗效及作用机制。方法将60只28周龄NZB／WF1狼疮样小鼠随机分为赋型剂组和紫草素低剂量组、高剂量组灌胃治疗14周．分别检测各组治疗前、后小鼠的尿蛋白和血。肾功能、抗双链DNA抗体、血清可溶性黏附分子,并观察各组小鼠肾组织病理学改变,同时采用RT—PCR法检测各组肾组织可溶性血管细胞黏附分子（VCAM一1）和可溶性细胞问黏附分子（ICAM一1）mRNA的表达水平。结果紫草素各组小鼠尿蛋白、血肾功能、血清可溶性黏附分子水平、肾组织VCAM一1和ICAM-1mRNA表达水平及肾小球损伤分级均较赋型剂组显著降低（均P〈0．05或0.01）。结论紫草素可减少NZB／WF1狼疮样小鼠尿蛋白水平,并可改善其肾功能和减轻肾脏病理损害,其作用机制可能与调节肾组织VCAM一1和ICAM一1mRNA表达水平有关。