Chlorogenic acid alleviates renal fibrosis by reducing lipid accumulation in diabetic kidney disease through suppressing the Notch1 and Stat3 signaling pathway.

AIMS: Abnormal renal lipid metabolism causes renal lipid deposition, which leads to the development of renal fibrosis in diabetic kidney disease (DKD). The aim of this study was to investigate the effect and mechanism of chlorogenic acid (CA) on reducing renal lipid accumulation and improving DKD renal fibrosis. METHODS: This study evaluated the effects of CA on renal fibrosis, lipid deposition and lipid metabolism by constructing in vitro and in vivo models of DKD, and detected the improvement of Notch1 and Stat3 signaling pathways. Molecular docking was used to predict the binding between CA and the extracellular domain NRR1 of Notch1 protein. RESULTS: In vitro studies have shown that CA decreased the expression of Fibronectin, α-smooth muscle actin (α-SMA), p-smad3/smad3, alleviated lipid deposition, promoted the expression of carnitine palmitoyl transferase 1 A (CPT1A), and inhibited the expression of cholesterol regulatory element binding protein 1c (SREBP1c). The expression of Notch1, Cleaved Notch1, Hes1, and p-stat3/stat3 were inhibited. These results suggested that CA might reduce intercellular lipid deposition in human kidney cells (HK2) by inhibiting Notch1 and stat3 signaling pathways, thereby improving fibrosis. Further, in vivo studies demonstrated that CA improved renal fibrosis and renal lipid deposition in DKD mice by inhibiting Notch1 and stat3 signaling pathways. Finally, molecular docking experiments showed that the binding energy of CA and NRR1 was -6.6 kcal/mol, which preliminarily predicted the possible action of CA on Notch1 extracellular domain NRR1. CONCLUSION: CA reduces renal lipid accumulation and improves DKD renal fibrosis by inhibiting Notch1 and stat3 signaling pathways.

Targeting the TNF-α-TNFR interaction with EGCG to block NF-κB signaling in human synovial fibroblasts.

The tumor necrosis factor alpha (TNF-α)-TNF-α receptor (TNFR) interaction plays a central role in the pathogenesis of various autoimmune diseases, particularly rheumatoid arthritis, and is therefore considered a key target for drug discovery. However, natural compounds that can specifically block the TNF-α-TNFR interaction are rarely reported. (-)-Epigallocatechin-3-gallate (EGCG) is the most active, abundant, and thoroughly investigated polyphenolic compound in green tea. However, the molecular mechanism by which EGCG ameliorates autoimmune arthritis remains to be elucidated. In the present study, we found that EGCG can directly bind to TNF-α, TNFR1, and TNFR2 with similar µM affinity and disrupt the interactions between TNF-α and TNFR1 and TNFR2, which inhibits TNF-α-induced L929 cell death, blocks TNF-α-induced NF-κB activation in 293-TNF-α response cell line, and eventually leads to inhibition of TNF-α-induced NF-κB signaling pathway in HFLS and MH7A cells. Thus, regular consumption of EGCG in green tea may represent a potential therapeutic agent for the treatment of TNF-α-associated diseases.

Sinomenine Hydrochloride Can Ameliorate Benign Prostatic Hyperplasia by Lowering the 5α-Reductase 2 Level and Regulating the Balance between the Proliferation and Apoptosis of Cells.

Benign prostatic hyperplasia (BPH) is a chronic disease that affects the quality of life of older males. Sinomenine hydrochloride (SIN) is the major bioactive alkaloid isolated from the roots of the traditional Chinese medicinal plant Sinomenium acutum Rehderett Wilson. We wondered if the SIN administration exerted a regulatory effect on BPH and its potential mechanism of action. Mice with testosterone propionate-induced BPH subjected to bilateral orchiectomy were employed for in vivo experiments. A human BPH cell line (BPH-1) was employed for in vitro experiments. SIN administration inhibited the proliferation of BPH-1 cells (p < 0.05) by regulating the expression of androgen-related proteins (steroid 5-alpha reductase 2 (SRD5A2), androgen receptors, prostate-specific antigen), apoptosis-related proteins (B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax)) and proliferation-related proteins (proliferating cell nuclear antigen (PCNA), mammalian target of rapamycin, inducible nitric oxide synthase) in vitro. SIN administration decreased the prostate-gland weight coefficient (p < 0.05) and improved the histological status of mice suffering from BPH. The regulatory effects of SIN administration on SRD5A2, an apoptosis-related protein (Bcl-2), and proliferation-related proteins (PCNA, matrix metalloproteinase-2) were consistent with in vitro data. SIN exerted a therapeutic effect against BPH probably related to lowering the SRD5A2 level and regulating the balance between the proliferation and apoptosis of cells. Our results provide an important theoretical basis for the development of plant medicines for BPH therapy.

Dimeric-(-)-epigallocatechin-3-gallate inhibits the proliferation of lung cancer cells by inhibiting the EGFR signaling pathway.

Non-small cell lung cancer (NSCLC) is one of the most general malignant tumors. The overexpression of epidermal growth factor receptor (EGFR) is a common marker in NSCLC, and it plays an important role in the proliferation, invasion, and metastasis of cancer cells. At present, drugs developed with EGFR as a target suffer from drug resistance, so it is necessary to study new compounds for the treatment of NSCLC. The active substance in green tea is EGCG, which has anti-cancer effects. In this study, we synthesized dimeric-(-)-epigallocatechin-3-gallate (prodelphinidin B-4-3,3‴-di-O-gallate, PBOG), and explored the effect of PBOG on lung cancer cells. PBOG can inhibit the proliferation and migration of NCI-H1975 cells, promote cell apoptosis, and inhibit cell cycle progression. In addition, PBOG can bind to the EGFR ectodomain protein and change the secondary structure of the protein. At the same time, PBOG decreases the expression of EGFR and downstream protein phosphorylation. Animal experiments confirmed that PBOG can inhibit tumor growth by inhibiting EGFR phosphorylation. Collectively, our study results show that PBOG may induce a decrease in intracellular phosphorylated EGFR expression by binding to the EGFR ectodomain protein, thereby inducing apoptosis and inhibiting cell cycle progression, thus providing a new strategy to treat lung cancer.

Tereticornate A suppresses RANKL-induced osteoclastogenesis via the downregulation of c-Src and TRAF6 and the inhibition of RANK signaling pathways.

Excessive osteoclast differentiation and activation are closely associated with the development and progression of osteoporosis. Natural plant-derived compounds that can inhibit osteoclastogenesis are an efficient strategy for the prevention and treatment of osteoporosis. Tereticornate A (TA) is a natural terpene ester compound extracted from the leaves and branches of Eucalyptus gracilis, with antiviral, antibacterial, and anti-inflammatory activities. However, the effect of TA on osteoclastogenesis and the underlying molecular mechanism remain unclear. Based on the key role of the NF-κB pathway in the regulation of osteoclastogenesis and the observation that TA exhibits an anti-inflammatory effect by inhibiting NF-κB activity, we speculated that TA could exert anti-osteoclastogenesis activity. Herein, TA could inhibit the RANKL-induced osteoclast differentiation and formation of F-actin rings in RAW 264.7 cells. Mechanistically, TA downregulated the expression of c-Src and TRAF6, and also suppressed the RANKL-stimulated canonical RANK signaling pathways, including AKT, MAPK (p38, JNK, and ERK), and NF-κB; ultimately, downregulating the expression of NFATc1 and c-Fos, the key transcriptional factors required for the expression of genes (e.g., TRAP, cathepsin K, ß-Integrin, MMP-9, ATP6V0D2, and DC-STAMP) that govern osteoclastogenesis. Our findings demonstrated that TA could effectively inhibit RANKL-induced osteoclastogenesis via the downregulation of c-Src and TRAF6 and the inhibition of RANK signaling pathways. Thus, TA could serve as a novel osteoclastogenesis inhibitor and might have beneficial effects on bone health.

Niloticin inhibits osteoclastogenesis by blocking RANKL-RANK interaction and suppressing the AKT, MAPK, and NF-κB signaling pathways.

Dysregulation of osteoclasts or excessive osteoclastogenesis significantly -contributes to the occurrence and development of osteolytic diseases, including osteoporosis, inflammatory bone erosion, and tumor-induced osteolysis. The protein-protein interaction between the receptor activator of nuclear factor (NF)-κB (RANK) and its ligand (RANKL) mediates the differentiation and activation of osteoclasts, making it a key therapeutic target for osteoclastogenesis inhibition. However, very few natural compounds exerting anti-osteoclastogenesis activity by inhibiting the RANKL-RANK interaction have been found. Niloticin is a natural tetracyclic triterpenoid compound with anti-viral, antioxidative, and mosquitocidal activities. However, its role in osteoclastogenesis remains unknown. The present study found that niloticin directly binds to RANK with an equilibrium dissociation constant of 5.8 µM, blocking RANKL-RANK interaction, thereby inhibiting RANKL-induced AKT, MAPK (p38, JNK, and ERK1/2), and NF-κB (IKKα/ß, IκBα, and p65) pathways activation, and reducing the expression of key osteoclast differentiation-related regulatory factors (NFATc1, c-Fos, TRAP, c-Src, ß3-Integrin, and cathepsin K) in osteoclast precursors, ultimately negatively regulating osteoclastogenesis. These findings suggest that niloticin could serve as a novel osteoclastogenesis inhibitor and might have beneficial effects on bone health.

Roburic Acid Targets TNF to Inhibit the NF-κB Signaling Pathway and Suppress Human Colorectal Cancer Cell Growth.

Tumor necrosis factor (TNF)-stimulated nuclear factor-kappa B (NF-κB) signaling plays very crucial roles in cancer development and progression, and represents a potential target for drug discovery. Roburic acid is a newly discovered tetracyclic triterpene acid isolated from oak galls and exhibits anti-inflammatory activity. However, whether roburic acid exerts antitumor effects through inhibition of TNF-induced NF-κB signaling remains unknown. Here, we demonstrated that roburic acid bound directly to TNF with high affinity (KD = 7.066 µM), blocked the interaction between TNF and its receptor (TNF-R1), and significantly inhibited TNF-induced NF-κB activation. Roburic acid exhibited antitumor activity in numerous cancer cells and could effectively induce G0/G1 cell cycle arrest and apoptosis in colorectal cancer cells. Importantly, roburic acid inhibited the TNF-induced phosphorylation of IKKα/ß, IκBα, and p65, degradation of IκBα, nuclear translocation of p65, and NF-κB-target gene expression, including that of XIAP, Mcl-1, and Survivin, in colorectal cancer cells. Moreover, roburic acid suppressed tumor growth by blocking NF-κB signaling in a xenograft nude mouse model of colorectal cancer. Taken together, our findings showed that roburic acid directly binds to TNF with high affinity, thereby disrupting its interaction with TNF-R1 and leading to the inhibition of the NF-κB signaling pathway, both in vitro and in vivo. The results indicated that roburic acid is a novel TNF-targeting therapeutics agent in colorectal cancer as well as other cancer types.

FAEE exerts a protective effect against osteoporosis by regulating the MAPK signalling pathway.

CONTEXT: Ferulic acid ethyl ester (FAEE) is abundant in Ligusticum chuanxiong Hort. (Apiaceae) and grains, and possesses diverse biological activities; but the effects of FAEE on osteoporosis has not been reported. OBJECTIVE: This study investigated whether FAEE can attenuate osteoclastogenesis and relieve ovariectomy-induced osteoporosis via attenuating mitogen-activated protein kinase (MAPK). MATERIALS AND METHODS: We stimulated RAW 264.7 cells with receptor activator of NF-κB ligand (RANKL) followed by FAEE. The roles of FAEE in osteoclast production and osteogenic resorption of mature osteoclasts were evaluated by tartrate resistant acid phosphatase (TRAP) staining, expression of osteoclast-specific genes, proteins and MAPK. Ovariectomized (OVX) female Sprague-Dawley rats were administered FAEE (20 mg/kg/day) for 12 weeks to explore its potential in vivo, and then histology was undertaken in combination with cytokines analyses. RESULTS: FAEE suppressed RANKL-induced osteoclast formation (96 ± 0.88 vs. 15 ± 1.68) by suppressing the expression of osteoclast-specific genes, proteins and MAPK signalling pathway related proteins (p-ERK/ERK, p-JNK/JNK and p-P38/P38) in vitro. In addition, OVX rats exposed to FAEE maintained their normal calcium (Ca) (2.72 ± 0.02 vs. 2.63 ± 0.03, p < 0.05) balance, increased oestradiol levels (498.3 ± 9.43 vs. 398.7 ± 22.06, p < 0.05), simultaneously reduced levels of bone mineral density (BMD) (0.159 ± 0.0016 vs. 0.153 ± 0.0025, p < 0.05) and bone mineral content (BMC) (0.8 ± 0.0158 vs. 0.68 ± 0.0291, p < 0.01). DISCUSSION AND CONCLUSIONS: These findings suggested that FAEE could be used to ameliorate osteoporosis by the MAPK signalling pathway, suggesting that FAEE could be a potential therapeutic candidate for osteoporosis.

Ellagic Acid Exerts Beneficial Effects on Hyperuricemia by Inhibiting Xanthine Oxidase and NLRP3 Inflammasome Activation.

Hyperuricemia is a metabolic disease caused by impaired uric acid (UA) metabolism. Ellagic acid (EA) is a natural small-molecule polyphenolic compound with known antioxidative and anti-inflammatory properties. Here, we evaluated the regulatory effects of EA on hyperuricemia and explored the underlying mechanisms. We found that EA is an effective xanthine oxidase (XOD) inhibitor (IC50 = 165.6 µmol/L) and superoxide anion scavenger (IC50 = 27.66 µmol/L). EA (5 and 10 µmol/L) treatment significantly and dose-dependently reduced UA levels in L-O2 cells; meanwhile, intraperitoneal EA administration (50 and 100 mg/kg) also significantly reduced serum XOD activity and UA levels in hyperuricemic mice and markedly improved their liver and kidney histopathology. EA treatment significantly reduced the degree of foot edema and inhibited the expression of NLPR3 pathway-related proteins in foot tissue of monosodium urate (MSU)-treated mice. The anti-inflammatory effect was also observed in lipopolysaccharide-stimulated RAW-264.7 cells. Furthermore, EA significantly inhibited the expressions of XOD and NLRP3 pathway-related proteins (TLR4, p-p65, caspase-1, TNF-α, and IL-18) in vitro and in vivo. Our results indicated that EA exerts ameliorative effects in experimental hyperuricemia and foot edema via regulating the NLRP3 signaling pathway and represents a promising therapeutic option for the management of hyperuricemia.

Proliferation of MDA-MB-231 can be suppressed by dimeric-epigallocatechin gallate through competitive inhibition of amphiregulin-epidermal growth factor receptor signaling.

Triple-negative breast cancer (TNBC) is highly aggressive, with high rates of early relapse and very poor overall prognosis. Amphiregulin (AREG) is the most abundant epidermal growth factor receptor (EGFR) agonist in MDA-MB-231 TNBC cells, whose proliferation can be inhibited by (-)-epigallocatechin gallate (EGCG), a constituent of green tea that is prone to oxidative polymerization. The effect of dimeric-EGCG, a dimer of oxidized and polymerized EGCG, on MDA-MB-231 cell the proliferation warrants further exploration. In the present study, MTT, flow cytometry, migration scratch, transwell, western blotting, and surface plasmon resonance assays were used to evaluate the effect of dimeric-EGCG on MDA-MB-231 cells and explore the underlying mechanism. MDA-MB-231 cell proliferation and migration were significantly inhibited by dimeric-EGCG at concentrations as low as 10 µM. Levels of EGFR and p44/42 MAPK phosphorylation in MDA-MB-231 cells were significantly reduced by treatment with 10 µM dimeric-EGCG (P < 0.01). In addition, the levels of phosphorylation induced by exogenous AREG were also inhibited by dimeric-EGCG (P < 0.01); however, no significant effects of dimeric-EGCG were observed on epidermal growth factor or transforming growth factor-alpha signaling. Surface plasmon resonance analysis demonstrated that 10 µM dimeric-EGCG bound directly to the extracellular domain of EGFR, competitively inhibiting the binding of AREG to EGFR. These results suggest a novel mechanism underlying the inhibitory effect of dimeric-EGCG on MDA-MB-231 cells, with potential application in the development of drugs for the treatment of TNBC.

Caffeine Targets G6PDH to Disrupt Redox Homeostasis and Inhibit Renal Cell Carcinoma Proliferation.

Glucose-6-phosphate dehydrogenase (G6PDH) is the rate-limiting enzyme in the pentose phosphate pathway (PPP) and plays a crucial role in the maintenance of redox homeostasis by producing nicotinamide adenine dinucleotide phosphate (NADPH), the major intracellular reductant. G6PDH has been shown to be a biomarker and potential therapeutic target for renal cell carcinoma (RCC). Here, we report a previously unknown biochemical mechanism through which caffeine, a well-known natural small molecule, regulates G6PDH activity to disrupt cellular redox homeostasis and suppress RCC development and progression. We found that caffeine can inhibit G6PDH enzymatic activity. Mechanistically, caffeine directly binds to G6PDH with high affinity (K D = 0.1923 µM) and competes with the coenzyme NADP+ for G6PDH binding, as demonstrated by the decreased binding affinities of G6PDH for its coenzyme and substrate. Molecular docking studies revealed that caffeine binds to G6PDH at the structural NADP+ binding site, and chemical cross-linking analysis demonstrated that caffeine inhibits the formation of dimeric G6PDH. G6PDH inhibition abrogated the inhibitory effects of caffeine on RCC cell growth. Moreover, inhibition of G6PDH activity by caffeine led to a reduction in the intracellular levels of NADPH and reactive oxygen species (ROS), and altered the expression of redox-related proteins in RCC cells. Accordingly, caffeine could inhibit tumor growth through inhibition of G6PDH activity in vivo. Taken together, these results demonstrated that caffeine can target G6PDH to disrupt redox homeostasis and inhibit RCC tumor growth, and has potential as a therapeutic agent for the treatment of RCC.

Caffeine inhibits the anticancer activity of paclitaxel via down-regulation of α-tubulin acetylation.

Caffeine (1,3,7-trimethylxanthine) is a xanthine alkaloid found in a number of dietary products consumed worldwide, such as coffee, tea, and soft beverages, and is known to act as a modifying agent for cytotoxic chemotherapeutic drugs. Studies have shown that caffeine reduces the cytotoxic effects of paclitaxel and inhibits paclitaxel-induced apoptosis; however, the underlying mechanism remains unclear. Here, we investigated whether caffeine inhibits the antitumor activity of paclitaxel via down-regulation of α-tubulin acetylation. In vitro studies, involving MTT assay, wound-healing assay, cell apoptosis assay, and western blotting analysis of A549 and HeLa cells, were performed. A549 and HeLa cell-based xenografts were established, and western blotting and immunohistochemical staining were performed for in vivo studies. The results showed that caffeine promoted the growth of cancer cells treated with paclitaxel. Additionally, caffeine enhanced migration ability, inhibited apoptosis, and decreased the acetylation of α-tubulin in paclitaxel-treated cancer cells. Furthermore, caffeine decreased the inhibitory effect of paclitaxel on tumor growth through down-regulation of α-tubulin acetylation in vivo. Taken together, these findings demonstrate that caffeine inhibits the anticancer activity of paclitaxel via down-regulation of α-tubulin acetylation, suggesting that patients receiving treatment with taxanes, such as paclitaxel, should avoid consuming caffeinated beverages or foods.

Effect of caffeine on ovariectomy-induced osteoporosis in rats.

Caffeine (1,3,7-trimethylxanthine) is a naturally occurring plant xanthine alkaloid present in many commonly consumed beverages worldwide, including tea, coffee, and cocoa. Although moderate caffeine intake is generally considered to exert positive effects on human health, its effect on bone metabolism remains controversial. The aim of this study was to systematically evaluate the pharmacological effect of long-term administration of caffeine on ovariectomy-induced postmenopausal osteoporosis in female rats. A sham operation or ovariectomy was performed to establish the ovariectomy rat model. The ovariectomized (OVX) rats were divided into five subgroups: OVX with vehicle (model), OVX with raloxifene hydrochloride (RLX, positive control; 4 mg/kg body weight/day), and OVX with low-, medium-, and high-dose caffeine (9.6, 19.2, and 38.4 mg/kg of body weight/day, respectively). Their corresponding treatments were administered intragastrically for 13 weeks. In-vivo studies showed that treatment with caffeine effectively improved the lipid profiles and increased the concentration of calcium in the serum of OVX rats. Medium- or high-dose treatment with caffeine significantly decreased the activities of alkaline and acid phosphatases in OVX rats. In addition, treatment with caffeine (at any dose) did not adversely affect organ weights, organ coefficients, femoral length, bone mineral density, biomechanical properties, or bone microarchitecture in OVX rats. Collectively, our study demonstrated that caffeine did not exert a damaging effect on the skeletal system of OVX rats.

Interactions between ß-cyclodextrin and tea catechins, and potential anti-osteoclastogenesis activity of the (-)-epigallocatechin-3-gallate-ß-cyclodextrin complex.

Galloylated catechins, the most important secondary metabolites in green tea including (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate, constitute nearly 75% of all tea catechins and have stronger health effects than non-galloylated catechins such as (-)-epigallocatechin and (-)-epicatechin. EGCG is the most abundant, active, and thoroughly investigated compound in green tea, and its bioactivity might be improved by complexing with ß-cyclodextrin (ß-CD). We investigated interactions between four catechins and ß-CD in a PBS buffer solution of pH 6.5 at 25 °C using biolayer interferometry and isothermal titration calorimetry, and to determine whether ß-CD could enhance the anti-osteoclastogenesis effect of EGCG. ß-CD could directly bind galloylated catechins at a stoichiometric ratio close to 1 : 1, with high specificities and affinities, and these inclusion interactions were primarily enthalpy-driven processes. We synthesized the EGCG-ß-CD complex and identified it using infrared radiation and nuclear magnetic resonance spectra. Interestingly, we revealed that the EGCG-ß-CD complex could inhibit osteoclastogenesis significantly more than EGCG.

Theabrownin suppresses in vitro osteoclastogenesis and prevents bone loss in ovariectomized rats.

Drinking tea exhibits beneficial effects on bone health and may protect against osteoporosis, particularly in postmenopausal women. Theabrownin (TB) is the main component responsible for the biological activities of Pu-erh tea, but whether it possesses anti-osteoporotic potential remains unknown. Here we investigated the in vitro and in vivo anti-osteoporotic effects of TB in the RAW 264.7 cell line and ovariectomized (OVX) rats, respectively. Our in vitro studies showed that TB significantly suppressed RANKL-induced osteoclastogenesis and the expression of related marker proteins, including NFATc1, TRAP, c-Fos, and cathepsin K. In vivo studies showed that TB treatment effectively ameliorated blood biochemical parameters, organ weights and organ coefficients in OVX rats. In addition, TB treatment significantly improved femoral bone mineral density (BMD) and biomechanical properties. What's more, TB treatment strikingly ameliorated bone microarchitecture in OVX rats because of increased cortical bone thickness and trabecular bone area in the femur. Our study therefore demonstrated that TB can inhibit RANKL-induced osteoclastogenesis in vitro and prevent bone loss in ovariectomized rats. Consequently, TB has a promising potential in postmenopausal osteoporosis treatment.

(-)-Epigallocatechin Gallate Targets Notch to Attenuate the Inflammatory Response in the Immediate Early Stage in Human Macrophages.

Inflammation plays important roles at different stages of diabetes mellitus, tumorigenesis, and cardiovascular diseases. (-)-Epigallocatechin gallate (EGCG) can attenuate inflammatory responses effectively. However, the immediate early mechanism of EGCG in inflammation remains unclear. Here, we showed that EGCG attenuated the inflammatory response in the immediate early stage of EGCG treatment by shutting off Notch signaling and that the effect did not involve the 67-kDa laminin receptor, the common receptor for EGCG. EGCG eliminated mature Notch from the cell membrane and the nuclear Notch intercellular domain, the active form of Notch, within 2 min by rapid degradation via the proteasome pathway. Transcription of the Notch target gene was downregulated simultaneously. Knockdown of Notch 1/2 expression by RNA interference impaired the downregulation of the inflammatory response elicited by EGCG. Further study showed that EGCG inhibited lipopolysaccharide-induced inflammation and turned off Notch signaling in human primary macrophages. Taken together, our results show that EGCG targets Notch to regulate the inflammatory response in the immediate early stage.

Oxidative Tea Polyphenols Greatly Inhibit the Absorption of Atenolol.

Oxidative tea polyphenols (OTPs) is the oxidative polymerization product of epigallocatechin-3-O-gallate (EGCG) forms during the process of Pu-er tea fermentation, and possesses absorption property, which may absorbs on drugs thus impact the drug bioavailability when taking medicines with Pu-er tea. Here we demonstrated that OTP inhibited the absorption of atenolol in the intestine, which was determined by testing atenolol levels of plasma via high performance liquid chromatography (HPLC). After administration of atenolol (50 mg/kg), atenolol was absorbed (T max: 1.867 h) with the half-life (t1/2) of 6.663 h in control group; Compared with atenolol group, AUC0-t (h*ng/ml), AUC0-∞(h(∗)ng/ml), and C max of OTP+atenolol group (OTP 500 mg/kg + atenolol 50 mg/kg) reduced 38.7, 27, and 51%, respectively, the atenolol concentration of plasma was reduced by OTP approximately 43, 49, and 55.5% at 30 min, 1 and 2 h, respectively, (P < 0.01). Furthermore, the level of atenolol in feces was higher in the OTP+atenolol group, indicating that the absorption of atenolol in rats was inhibited by OTP. Isothermal titration calorimetry assay identified that EGCG can bind to atenolol and the in vitro results showed that OTP absorbed on atenolol and formed precipitate in acid condition, demonstrating a significant positive relationship between atenolol levels and OTP dosage. Taken together, these results suggested that consuming Pu-er tea with atenolol might inhibit atenolol absorption and possible other drugs.

Expression and purification of human MHC class I-related chain molecule B-α1 domain.

Major histocompatibility complex (MHC) class I-related chain A/B (MICA/B) is a type of stress-induced molecule that plays an important role in tumor surveillance. MICA/B shares a similar structure with MHC class I molecules, but MICA/B contains a closed cleft, not an open one, in its N-terminal alpha1 domain. The alpha 1 domain was believed to have no roles in antigen presentation, because the closed cleft provides limited space for binding with known molecules, and the cleft of MICA/B have been reported no known functions. To study the possible function of the cleft located in human MICA/B's alpha 1 domain, we attempted to express the human MICB-α1 (hMICB-α1) domain allele protein, which is approximately 20.5 kDa, by utilizing an Escherichia coli (E. coli) secretory pathway. Protein expression was accomplished through the phosphate-limited inducible promoter. After purification using ammonium sulfate precipitation, phenyl hydrophobic Sepharose, SP Sepharose and HisTrap affinity Sepharose, recombinant human MICB-α1 (rhMICB-α1) was obtained with 94.3% purity. The binding capacity of rhMICB-α1 with natural killer group 2, member D (NKG2D) was evaluated in vitro. The results demonstrated that rhMICB-α1 can be prepared through the E. coli secretory pathway. Purified rhMICB-α1 protein was able to functionally bind with NKG2D. This method can be further used to obtain functionally active rhMICB-α1 protein, which can served as the basis for further studies of the possible function of the MICB cleft.

Immunization with a HSP65-HER2 fusion peptide selectively eliminates HER2(+) B16 melanoma cells in a xenograft tumor mouse model.

HER2/neu peptide-based vaccines can eliminate human tumors overexpressing the human epidermal growth factor receptor 2 (HER2/neu), but the efficacy of this therapeutic strategy is suboptimal. Heat shock proteins (HSPs) are capable of eliciting efficient cytotoxic T lymphocyte (CTL) responses by cross-presentation. To evaluate whether immunization with a HSP65-HER2 fusion peptide could selectively eliminate HER2(+) B16 melanoma cells in a xenograft tumor mouse model, a HSP65-HER2 fusion peptide was incubated with immature dendritic cells (iDCs) in vitro to determine whether loading of iDCs with HSP65-HER2 could induce the expression of the immunomodulatory cell surface molecule, CD86. In vivo mouse immunizations with HSP65-HER2 or PBS (control) were performed to determine the antitumor effects by longitudinally monitoring changes in tumor volume, weight, and incidence. The effects on percentages of HER2(+) B16 cells in tumors were assessed by confocal microscopy and flow cytometry. The results indicated that loading of iDCs with HSP65-HER2 induced the expression of CD86 in vitro, suggesting that the hybrid antigen was able to stimulate an immune response. Immunization with HSP65-HER2 had no significant influence on tumor weight or volume but significantly reduced tumor incidence (62.5 % in mice injected with 25 µg of HSP65-HER2 vs. 100 % in PBS-injected controls; P < 0.05). Confocal microscopy and flow cytometry analyses revealed that HSP65-HER2 immunization significantly reduced the percentages of HER2(+) B16 cells in xenografted tumors (1.86 % vs. 30.56 % in PBS-injected controls; P = 0.01). Our findings suggest that immunization with the HSP65-HER2 fusion peptide selectively eliminates HER2(+) B16 melanoma cells in a xenograft tumor mouse model and may represent a novel and efficacious targeted therapy of HER2/neu(+) tumors.

[Establishment of a B16 cell line stably expressing genes encoding HER2 multi-epitope peptides in vivo].

AIM: To establish a B16 cell line stably expressing genes encoding HER2 multi-epitope peptides in vivo. METHODS: Eukaryotic expressing vector pcDNA3-GFP-HER2 was constructed by molecular cloning technique and transfected into B16 cells mediated by cationic liposome. After screened with G418, the transfected cells were passaged in vivo. The GFP-HER2 positive cells were isolated from tumor burdening mice by flow cytometry (FCM) sorting, and then monoclonized in the absence of G418 to obtain a B16 cell line stably expressing genes encoding HER2 multi-epitope peptides in vivo. This cell line was then identified after being passaged in vivo. RESULTS: Restriction endonulease analysis and DNA sequencing showed that the pcDNA3-GFP-HER2 was constructed and a B16 cell line stably expressing genes encoding HER2 multi-epitope peptides in vivo was obtained successfully. The GFP-HER2 positive proportion maintained higher than 90% after being passaged in vivo. CONCLUSION: A B16 cell line stably expressing genes encoding HER2 multi-epitope peptides is established successfully, which would provide a method to establish other cell lines stably expressing exogenous genes.