Triptolide inhibits human breast cancer MCF-7 cell growth via downregulation of the ERα-mediated signaling pathway

Aim:

To investigate the anticancer mechanisms of triptolide, a diterpenoid isolated from the plant Tripterygium wilfordii Hook F, against human breast cancer cells and the involvement of the estrogen receptor-α (ERα)-mediated signaling pathway in particular.

Methods:

Human breast cancer ERα-positive MCF-7 cells and ERα-negative MDA-MB-231 cells were tested. PrestoBlue assay was used to evaluate the cell viability. The levels of ERα mRNA and protein were detected with real-time PCR and immunoblotting, respectively. Mouse models of MCF-7 or MDA-MB-231 xenograft tumors were treated with triptolide (0.4 mg·kg⁻¹·d⁻¹, po) or a selective estrogen receptor modulator tamoxifen (mg·kg⁻¹·d⁻¹, po) for 3 weeks, and the tumor weight and volume were measured.

Results:

Triptolide (5–200 nmol/L) dose-dependently inhibited the viability of both MCF-7 and MDA-MB-231 cells, with a more potent inhibition on MCF-7 cells. Knockdown of ERα in MCF-7 cells by siRNA significantly attenuated the cytotoxicity of triptolide, whereas overexpression of ERα in MDA-MB-231 cells markedly enhanced the cytotoxicity. Triptolide dose-dependently decreased the expression of ERα in MCF-7 cells and MCF-7 xenograft tumors. Furthermore, treatment of MCF-7 cells with triptolide inhibited the phosphorylation of ERK1/2 in dose- and time-dependent manners. In the mice xenografted with MCF-7 cells, treatment with triptolide or tamoxifen resulted in significant reduction in the tumor weight and volume. Similar effects were not obtained in the mice xenografted with MDA-MB-231 cells.

Conclusion:

The anticancer activity of triptolide against ERα-positive human breast cancer is partially mediated by downregulation of the ERα-mediated signaling pathway.     

Cobalt-catalyzed C(sp3)–H/C(sp2)–H oxidative coupling between alkanes and benzamides

A direct cobalt-catalyzed oxidative coupling between C(sp²)–H in unactivated benzamides and C(sp³)–H in simple alkanes, ethers and toluene derivatives was explored. This protocol achieves direct C–C formation without using alkyl or aryl halide surrogates and exhibits high practicality with ample substrate scope. The method provides a new way to construct linear and five- or six-membered ring moieties in bioactive molecules.

A direct cobalt-catalyzed oxidative coupling between C(sp²)–H in unactivated benzamides and C(sp³)–H in simple alkanes, ethers and toluene derivatives was explored.     

A novel linear neutralizing epitope of hepatitis E virus

Hepatitis E virus (HEV) is a serious public health problem that causes acute hepatitis in humans and is primarily transmitted through fecal and oral routes. The major anti-HEV antibody responses are against conformational epitopes located in a.a. 459–606 of HEV pORF2. All reported neutralization epitopes are present on the dimer domain constructed by this peptide. While looking for a neutralizing monoclonal antibody (MAb)-recognized linear epitope, we found a novel neutralizing linear epitope (L2) located in a.a. 423–437 of pORF2. Moreover, epitope L2 is proved non-immunodominant in the HEV-infection process. Using the hepatitis B virus core protein (HBc) as a carrier to display this novel linear epitope, we show herein that this epitope could induce a neutralizing antibody response against HEV in mice and could protect rhesus monkeys from HEV infection. Collectively, our results showed a novel non-immunodominant linear neutralizing epitope of hepatitis E virus, which provided additional insight of HEV vaccine.     

Laccase immobilization and surface modification of activated carbon fibers by bio-inspired poly-dopamine

In this study, we developed a new synthesis method for modifying activated carbon fibers (ACFs) by dopamine with oxidation-based self-polymerization (DA-ACFs). In addition, laccase was immobilized on the surface of unmodified ACFs (L-ACFs) and DA-ACFs (LDA-ACFs) via cross-linking after being incubated for 12 h at 5 °C. The surface composition and microstructure of the samples were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, attenuated total reflectance Fourier-transform infrared reflection and thermo-gravimetric analysis. The optimized laccase concentration for preparing the samples was 2.0 g L⁻¹. The results demonstrated that the successful poly-dopamine modification increased the catalytic abilities of the ACFs in terms of biocompatibility and hydrophilicity. Compared with free laccase, the immobilized laccase exhibited significantly higher relative activity over a pH range of 3.5–6.5 and a temperature range of 30–60 °C; the thermo-stability increased, and 50% relative activity of the LDA-ACFs remained after 5 h at 55 °C. After six cycles of reuse, the relative activity of LDA-ACFs remained ≥60%, compared to 40% activity remaining for L-ACFs, and long-term storage stability was demonstrated. Moreover, the kinetic parameters (K_m) of the two immobilized laccases were both higher than that of free laccase, whereas the maximum velocities (V_max) were lower. These results indicate that the DA-ACFs are economical, simple, and efficient carries for enzyme immobilization, and can be suitable for further biotechnology and environmental applications.

In this study, we developed a new synthesis method for modifying activated carbon fibers (ACFs) by dopamine with oxidation-based self-polymerization (DA-ACFs).     

国产吸附破伤风疫苗用于成人加强免疫的安全性及免疫原性观察

目的:评价成都欧林生物科技股份有限公司研制的吸附破伤风疫苗用于成人加强免疫的临床安全性与免疫原性。方法:分两阶段开展:第一阶段采用开放性设计,评价试验疫苗的安全性,在确认安全性的情况下开展第二阶段试验;第二阶段采用单中心、随机、盲法、同类制品平行对照的试验设计,选择18~30岁的常住健康人群,按1∶1的比例随机接种试验疫苗和阳性对照疫苗,使用日记卡记录接种后28 d内的不良反应/事件发生情况。采集免疫前和免疫后28 d的血液标本,使用标准酶联免疫吸附试验方法进行破伤风类毒素抗体浓度检测。结果:第一阶段招募30名受试者,试验疫苗接种后7 d内总体不良反应为33.3%;第二阶段试验组和阳性对照组各入组600人,总体不良反应发生率分别为30.7%和31.5%,以轻中度不良反应为主,最常见接种局部和全身不良反应分别为疼痛和发热,不良反应的发生在组间差异无统计学意义(P≥0.05)。加强免疫后试验组与阳性对照组均诱导较强的免疫反应:破伤风抗体浓度达到保护性水平的受试者比例均达到100%,GMC分别为3.38、3.16 U/ml。结论:成都欧林生物科技股份有限公司研制的吸附破伤风疫苗具有良好的安全性和免疫原性,适用于成人进行加强免疫和进一步进行联合疫苗的研制。     

Novel dual-site fluorescent probe for monitoring cysteine and sulfite in living cells

Fluorescent probes have been considered to be efficient tools for the visualization of physiological and pathological processes. Herein, a dual-site fluorescence probe denoted as LC-1 was developed for the detection of cysteine (Cys) and its metabolite SO₃²⁻. The probe was shown to be highly sensitive to Cys and SO₃²⁻ with a turn-on mode fluorescence signal through two emission channels under excitations at wavelengths of 320 nm and 440 nm. Notably, the LC-1 probe was also observed to be satisfactorily sensitive to Cys and SO₃²⁻ in the presence of other amino acids and reactive oxygen species (ROS). Meanwhile, LC-1 was shown to have low cytotoxicity and was successfully applied for imaging the metabolism of Cys in living cells.

A dual-site fluorescence probe LC-1 was developed for the detection of Cys and SO₃²⁻.     

质子泵抑制剂对华法林抗凝效果影响的研究进展

临床联用华法林与质子泵抑制剂的情况很多,鉴于华法林的治疗窗较窄,联用是否会影响华法林抗凝作用和增加出血风险,目前尚无定论。本文通过整合和分析国内外相关临床研究的证据,探讨各种质子泵抑制剂与华法林相互作用的机制和细胞色素P450（cytochrome P450）的CYP2C19基因多态性对两者相互作用的影响,发现华法林与泮托拉唑、雷贝拉唑联用相对较安全,但各研究对兰索拉唑、奥美拉唑、埃索美拉唑与华法林的相互作用是否具有临床意义仍存在争议,亟须进行前瞻性的多中心、随机、双盲、对照研究。     

Chromic-P32 phosphate treatment of implanted pancreatic carcinoma： Mechanism involved

AIM: To study the effects of chromic-P32 phosphate (32P colloids) interstitial administration in Pc-3 implanted pancreatic carcinoma, and investigate its anticancer mechanism. METHODS: Ninety-eight tumor bearing nude mice were killed at different time points after the injection of 32P colloids to the tumor core with observed radioactivity. The light microscopy, transmission electron microscopy (TEM) and immuno-histochemistry and flow cytometry were used to study the rates of tumor cell necrosis, proliferating cell nuclear antigen index, the micro vessel density (MVD). The changes of the biological response to the lymphatic transported 32P colloids in the inguinal lymph node (ILN) were dynamically observed, and the percentage of tumor cell apoptosis, and Apo2.7, caspase-3, Bcl-2, Bax-related gene expression were observed too. RESULTS: The half-life of effective medication is 13 d after injection of 32P colloids to the tumor stroma, in 1-6 groups, the tumor cell necrosis rates were 20%, 45%, 65%, 70%, 95% and 4%, respectively (F= 4.14-105.36, P<0.01). MVD were 38.5±4.0,28.0±2.9,17.0±2.9,8.8±1.5, 5.7±2.3 and 65.0±5.2 (t=11.9-26.1,P<0.01),respectively. Under TEM fairly differentiated Pc-3 cells were found. Thirty days after medication, tumors were shrunk and dried with scabs detached, and those in control group increased in size prominently with plenty of hypodermic blood vessels. In all animals the ILN were enlarged but in medicated animals they appeared later and smaller than those in control group.The extent of irradiative injury in ILN was positively correlated to the dosage of medication. Typical tumor cell apoptosis could be found under TEM in animals with intra-tumoral injection of low dosed 32P colloids. The peak of apoptosis occurred in 2.96 MBq group and 24 h after irradiation. In the course of irradiation induced apoptosis,the value of Bcl-2/Bax was down regulated; Apo2.7 and caspase-3 protein expression were prominently increased dose dependently. CONCLUSION: 32P colloids intra-tumor injection having prominent anticancer effectiveness may reveal the ability of promoting cell differentiation. The low dose 32P colloids may induce human pancreatic carcinoma Pc-3 implanted tumor cell apoptosis; Apo2.7, caspase-3, Bcl-2 and Bax protein participated in regulating the process of irradiation induced cell apoptosis.