The Antitumor Activity of Meisoindigo against Human Colorectal Cancer HT-29 Cells In Vitro and In Vivo

Abstract

The study was conducted to examine the antitumor activity of meisoindigo on HT-29 cells In Vitro and In Vivo. The cytotoxicity of meisoindigo was evaluated by MTT assay. The related genes and proteins were inspected with RT-PCR and western blot assay respectively, and the effects of meisoindigo on the cell cycle were analyzed by flow cytometry. The efficacy of meisoindigo In Vivo was evaluated in an HT-29 cell xenograft nude mice model. The results show that meisoindigo effectively inhibits HT- 29 cell proliferation (IC₅₀ 4.3 mmol/L), arrests HT-29 cells in G2/ M phase and induces HT-29 cell apoptosis. The downstream genes and proteins of GSK-3β(ser⁹) expression level decrease. Meisoindigo significantly inhibits the HT-29 xenograft tumors growth at the dose of 100 mg/kg. The mechanism of meisoindigo activity against HT-29 cells may be related to its inhibition of glycogen synthase kinase-3β, GSK-3β(ser⁹) phosphorylation in Wnt signaling pathway. These findings indicate the potential value of meisoindigo for the treatment of colorectal cancer.     

β-连环素在子宫内膜异位症发生发展中的作用

β-连环素(β-catenin)为一种胞内糖蛋白,可与E-钙粘素(E-cadherin)结合形成E-钙粘素/β-连环素复合体参与细胞连接,或介导Wnt信号转导通路。子宫内膜异位症(EMs)发生、发展的基本病理过程为:细胞黏附、侵袭及新生血管的形成,另外EMs的发生发展亦与雌激素有关。β-连环素可能通过E-钙粘素/β-连环素复合体参与EMs细胞的黏附,通过Wnt/β-连环素参与异位内膜细胞的侵袭及新生血管的形成和雌激素的异常调控。     

Transgenic Analysis of Signaling Pathways Required for Xenopus Tadpole Spinal Cord and Muscle Regeneration

The Xenopus tadpole has the capacity fully to regenerate its tail after amputation. Previously, we have established that this regeneration process requires the operation of several signaling pathways including the bone morphogenic protein, Wnt, and Fgf pathways. Here, we have addressed the signaling requirements for spinal cord and muscle regeneration in a tissue‐specific manner. Two methods were used namely grafts of transgenic spinal cord to a wild type host, and the use of the Tet‐on conditional transgenic system to express inhibitors in the individual tissues. For the grafting experiments, the tail was amputated through the graft, which contained a temperature inducible inhibitor of the Wnt‐β‐catenin pathway. For the Tet‐on experiments, treatment with doxycycline was used to induce cell autonomous inhibitors of the Wnt‐β‐catenin or the Fgf pathway in either spinal cord or muscle. The results show that both spinal cord and muscle regeneration depend on both the Wnt‐β‐catenin and the Fgf pathways. This experimental design also enables us to observe the effect of inhibition of regeneration of one tissue on the regeneration of the others. Regardless of the method of inhibition, we find that reduction of spinal cord regeneration reduces regeneration of other parts of the tail, including the myotomal muscles. In contrast, reduction of muscle regeneration has no effect on the regeneration of the spinal cord. In common with other regeneration systems, this indicates that soluble factors from the spinal cord are needed to promote the regeneration of the other tissues in the tail. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.     

Unexplained polyposis: a challenge for geneticists, pathologists and gastroenterologists

Two main colorectal polyposis syndromes have been described, familial adenomatous polyposis and MUTYH-associated polyposis syndromes. Some polyposis remains unexplained: 20% of adenomatous polyposis and serrated polyposis. The aim of this study was to evaluate in a cohort of patients with unexplained polyposis whether a genetic defect could be detected. Individuals presenting polyposis with more than 40 adenomas or more than 20 serrated polyps (hyperplastic, sessile serrated and mixed), without causative mutation identified, were included. Complementary explorations on APC or MUTYH were performed: search for APC mosaicism, splicing-affecting mutations, large genomic rearrangement of MUTYH. Four genes of Wnt pathway (AXIN2, PPP2R1B, WIF1, SFRP1) and two genes of transforming growth factor-β (TGF-β) pathway (SMAD4, BMPR1A) were screened for germline mutation. Twenty-five patients had an unexplained adenomatous polyposis (familial or sporadic). Five pathogenic mutations were found: four in APC gene (with one case of mosaicism) and one in BMPR1A gene. The exploration of APC mosaicism was better performed from adenoma DNA with high-resolution melting. The screening of the candidate genes did not find any causative mutation. Thirteen individuals had an unexplained serrated polyposis and a frameshift on SMAD4 gene was identified. All mutations were identified in familial cases of polyposis. After new pathological examination, both BMPR1A and SMAD4 cases were found to be associated with a juvenile polyposis while the polyposis was initially described as adenomatous or undetermined. In 17% (6/38) of the patients the causative mutation of the polyposis was identified. Genetic causes were heterogeneous. Sporadic polyposis patients must be considered as potential APC mosaicism. The histological classification of polyposis is strongly important in direct genetic exploration.     

Wnt信号通路在心脏发育中的功能

在分子水平探究心脏发育是研究先天性心脏病的先决条件,将对心脏疾病的诊疗以及心脏再生策略的研究具有重要意义。研究表明,Wnt信号通路分子在心脏的发育过程中有着多种作用。 Wnt蛋白是胞外生长因子,可以激活不同的胞内信号通路。该文就Wnt相关蛋白从心脏前体细胞早期分化到其后形态发生过程中对心脏发育的影响进行了综述。     

离体培养时Wnt3a对椭圆囊毛细胞再生的影响

目的 在小鼠椭圆囊体外培养模型上,通过Wnt3a激活经典WNT信号,与DMSO共同作用,研究其对椭圆囊毛细胞再生的影响。方法 40只小鼠随机分成8组。实验第一部分：小鼠椭圆囊经4mmol/L新霉素处理后,在不同浓度(0、25、100、200ng/mL)Wnt3a的培养液中继续培养1d,培养结束后对β-catenin,毛细胞纤毛及细胞核进行免疫荧光染色。实验第二部分：小鼠椭圆囊经4mmol/L新霉素处理后,在含25ng/mL Wnt3a的培养液中培养6d,分别在空白对照组,50μmol/L DAPT、0.1%DMSO、50μmol/L DAPT+25ng/mL Wnt3a培养液中继续培养7d,共培养14d。在所有培养过程中均加入10μmol/L Brdu。培养结束后Brdu,Myocin7a及细胞核进行免疫荧光染色。结果 实验第一部分：在25ng/mL Wnt3a组中可见β-catenin在支持细胞胞浆中有阳性表达,β-catenin阳性细胞数与其他各组比较差异具有统计学意义(P<0.01)。实验第二部分：DMSO组中可见Myosin7a染色阳性细胞,对照组、Wnt3a+DAPT组及DATP组中可见大量Brdu阳性细胞而未见Myosin7a染色阳性细胞,DMSO组中Myosin7a阳性细胞数与其他3组相比较,组间差异具有显著性(P<0.01)。结论 顺序联合应用Wnt3a和DMSO可通过激活经典WNT信号途径,促使椭圆囊内细胞向毛细胞样细胞转分化。     

Potential Targets for Prevention of Colorectal Cancer: a Focus on PI3K/Akt/mTOR and Wnt Pathways

Colorectal cancer (CRC) is one of the most common cancers in many parts of the world. Its development is a multi-step process involving three distinct stages, initiation that alters the molecular message of a normal cell, followed by promotion and progression that ultimately generates a phenotypically altered transformed malignant cell. Reports have suggested an association of the phosphoinositide-3-kinase (PI3K)/Akt pathway with colon tumorigenesis. Activation of Akt signaling and impaired expression of phosphatase and tensin homolog (PTEN) (a negative regulator of Akt) has been reported in 60-70% of human colon cancers and inhibitors of PI3K/Akt signaling have been suggested as potential therapeutic agents. Around 80% of human colon tumors possess mutations in the APC gene and half of the remainder feature β-catenin gene mutations which affect downstream signaling of the PI3K/Akt pathway. In recent years, there has been a great focus in targeting these signaling pathways, with natural and synthetic drugs reducing the tumor burden in different experiment models. In this review we survey the role of PI3K/Akt/mTOR and Wnt signaling in CRC.     

Wnt/β-catenin信号与胃癌防治研究进展

胃癌的发生、发展机制复杂,细胞信号通路异常活化在其中起着至关重要的作用。Wnt/β-catenin信号参与胃癌细胞的增
殖、侵袭和转移,并有效诱导胃癌的耐药和再生,是介导胃组织癌变的关键信号;靶向抑制Wnt/β-catenin能够抑制胃癌的生长、
侵袭转移,增加化疗药物的敏感性。本文对Wnt/β-catenin在胃癌发生和发展中的作用和干扰Wnt/β-catenin治疗胃癌的最新研
究进展进行综述,期望为胃癌的防治提供新的思路。