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Breast cancer is a malignant tumor with high mortality, and multidrug resistance (MDR) mediated by ABCG2 (ATP-Binding cassette G2) is an important cause of chemotherapy failure. It is an urgent problem to explore the mechanism of ABCG2-mediated drug resistance and its key molecules. Epithelial cell adhesion molecule (EpCAM) is involved in multiple tumor drug resistance and is closely related to breast cancer MDR. However, its role in ABCG2-mediated breast cancer drug resistance has not been clarified. The purpose of this study was to explore the regulation of EpCAM on ABCG2-mediated MDR in breast cancer cells and its mechanism. CCK8 cytotoxicity assays confirmed that the drug resistance of MCF-7/MX cell line to mitoxantrone (MX) was significantly increased compared with MCF-7 drug-sensitive strain of human breast cancer. Western blotting results showed that ABCG2 was highly expressed and EpCAM was up-regulated in MCF-7/MX cells compared with MCF-7. SiRNA knockdown of EpCAM in MCF-7/MX cells down-regulated ABCG2 expression and restored sensitivity to MX. Cell morphology was observed under an inverted microscope, and it was found that knocking down EpCAM reduced cell-cell connections between MCF-7/MX cells. The co-localization of EpCAM and claudin 1 in MCF-7/MX cells was observed by immunofluorescence. Furthermore, Western blotting results showed that EpCAM knockdown reduced claudin 1 expression in MCF-7/MX cells. In conclusion, EpCAM may promote ABCG2-mediated mMDR in breast cancers by enhancing intercellular tight junctions through interaction with claudin 1.
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OBJECTIVE@#To evaluate whether ultrafine particulates (UFPs) have direct deleterious effects on cardiac function through activating MAPK signaling.@*METHODS@#Langendorff-perfused Sprague-Dawley rat hearts were randomly divided into 2 groups (n=10/each group). In control group, the rat hearts were perfused with Tyrode's buffer for 40 min; in UFPs-treated group, the hearts were perfused with UFPs at a concentration of 12.5 mg/L. Cardiac function was determined by measuring left ventricular developed pressure (LVDP), left ventricular peak rate of contraction and relaxation (±dp/dtmax) and coronary flow (CF). The levels of malondialdehyde (MDA), superoxide dismutase (SOD), total anti-oxidant capacity (TAOC) were detected in order to evaluate cardiac oxidative stress via the thiobarbituric acid assay, water soluble tetrazolium salt assay and colorimetry, respectively. The expressions of p-p38 MAPK, p-ERKs and p-JNKs in the myocardium were observed using immunohistochemical staining and Western blots.@*RESULTS@#No significant changes in cardiac function were detected before and after the perfusion in control group while UFPs perfused hearts showed a decline in cardiac function in a time-dependent manner (all P < 0.05). In UFPs-treated group, LVDP, +dp/dtmax, -dp/dtmax and CF were statistically reduced from (82.6±2.1) mmHg, (1 624±113) mmHg/s, (1 565±116) mmHg/s, (12.0±0.2) mL/min to (56.8±4.4) mmHg, (1 066±177) mmHg/s, (1 082±134) mmHg/s, (8.7±0.3) mL/min (all P < 0.05), respectively. Furthermore, The comparison between the two groups observed that UFPs perfusion caused a significant decrease in cardiac function at 30 and 40 min compared with the control group (all P < 0.05). At the end of the perfusion, the level of MDA was increased from (0.98±0.14) nmol/L to (1.95±0.18) nmol/L, while SOD and TAOC were reduced from (12.50±1.87) U/mL and (6.83±1.16) U/mL to (6.50 ±1.04) U/mL and (3.67±0.82) U/mL (all P < 0.001) in UFPs group, respectively. In coincidence with these changes, immunohistochemistry and Western blots results showed that the levels of p-p38 MAPK, p-ERKs and p-JNKs in the myocardium significantly increased in UFPs group as compared with control group (all P < 0.05).@*CONCLUSION@#The results of this study demonstrated that the short-term exposure of UFPs to the isolated rat hearts has direct and acute toxic effects on cardiac function, probably related to attenuation of anti-oxidative capacity and activation of MAPK signaling pathways.
Subject(s)
Animals , Rats , Heart , Malondialdehyde/metabolism , Myocardium , Oxidative Stress , Rats, Sprague-DawleyABSTRACT
Aim: To investigate the effect of epithelial cell adhesion molecule (EpCAM) on metastasis and multidrug resistance of breast cancer and its mechanism. Methods Immunohistochemical staining was employed to detect the expression of EpCAM in adjacent non-tumor tissues (ANTTs) and breast cancer tissues. siRNA was applied to knock down EpCAM expression in MDA-MB-231 cells. Transwell assay was used to detect the invasion and migration ability of breast cancer cells. Western blot analysis was performed to determine the protein expression of EpCAM, epithelial mesenchymal transition (EMT) markers E-cadherin, N-cadherin and vimentin, breast cancer resistance protein (BCRP), and β-catenin. Results EpCAM immunoreactivity was consistently stronger in primary breast cancer tissues and even higher in metastatic lesions than that in ANTTs. The expression of EpCAM was significantly upregulated in triple negative breast cancer MDA-MB-231 cells. EpCAM knockdown using siRNA decreased the invasion and migration ability and BCRP expression, and partially reversed the EMT phenotypes of MDA-MB-231 cells, β-catenin expression was upregulated in MDA-MB-231 cells. ICG-001, a specific Wnt/β-catenin pathway inhibitor, downregulated the expression levels of EpCAM, N-cadherin, and vimentin in MDA-MB-231 cells. Conclusions EpCAM could promote metastasis and drug resistance of breast cancer through the induction of EMT, which is related to the Wnt/β-catenin signaling pathway.
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Objective::To explore the effect and mechanism of Portulacae Herba protecting carbon tetrachloride (CCl4)-induced acute liver injury. Method::Sixty Kunming mice were randomly divided into normal group, model group, silybin group (200 mg·kg-1) and Portulacae Herba high, medium, low (2, 1, 0.5 g·kg-1) dose groups. After continuous intragastric administration for 5 days, mice in each group were intraperitoneally injected with 0.2% CCl4 peanut oil solution to establish acute liver injury model, except normal mice. After 23 hours of modeling, serum and liver tissue were collected. Fully automatic analysis of serum serum liver function indicators in mice. Liver tissues were taken for hematoxylin-eosin staining (HE) staining to observe liver pathological changes. RNA Sequencing (RNA-seq) was used to analyze differential genes and functional enrichment, real-time fluorescence quantification PCR(Real-time PCR) was used to verify the mRNA expression of cytochrome P450 family members(CYP)26A1, CYP2C37, CYP2C44, CYP2C50, CYP2C54. Result::Compared with normal group, the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), total bilirubin (TBIL), malondialdehyde (MDA) in model group were significantly increased (P<0.05), and the activities of triglyceride (TG) and superoxide dismutase (SOD) were significantly decreased (P<0.05). Compared with model group, Portulaca Herba significantly reduced ALT, AST, TBIL and MDA levels in mice with acute liver injury (P<0.05), significantly increased SOD activity (P<0.01), and decreased the degree of liver tissue damage in mice. Compared with normal group, the mRNA expressions of CYP2C44, CYP2C50 in mice with acute liver injury were significantly decreased (P<0.05). Compared with model group, the mRNA expressions of CYP26A1, CYP2C37, CYP2C44, CYP2C50 and CYP2C54 were significantly increased in all dose groups of Portulaca Herba (P<0.05, P<0.01). Conclusion::Portulacae Herba has significant protective effects on acute liver injury caused by CCl4, and its mechanism may be related to the regulation of cytochrome P450 related genes.
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This study was aimed to investigate clinical features of Chinese metabolic syndrome (MS) subjects with normal urinary albumin to creatinine ratio (UACR) and to estimate independent correlation factor for UACR. Data were drawn from a cross-sectional survey in participants having MS. The patients with different grade of albuminuria were divided into 4 groups according to the value of UACR (<10, 10-20, 21-30, >30 mg/g). All underwent biochemical tests. Bioelectrical impedance body fat content, islet β-cell function and insulin sensitivity were measured. Multivariable linear regression models were applied to further determine association between UACR and clinical factors with adjustment. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1c), TG, fat mass, fat content and homeostasis model assessment for insulin resistance (HOMA-IR) were significantly higher in the group with UACR at 10-20 mg/g than those in the group with UACA lower than 10 mg/g (P<0.05). Multivariable linear regression showed that TG, HbA1c, waist-hip ratio (WHR) and SBP were independently associated with UACR. The patients with normal UACR had abnormal levels of MS components. The factors independently associated with UACR were TG, HbA1c, WHR and SBP.
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Albuminuria , Urine , Blood Glucose , China , Creatinine , Urine , Cross-Sectional Studies , Metabolic Syndrome , UrineABSTRACT
Objective To analyze the energy-absorption characteristics for four mesomechanical models of the cancellous bone at different locations with different mechanical properties. Methods Under one-way shocks, the finite element method was used to calculate the energy absorption characteristics of the four models. Results According to the energy absorption rate of four models, the model with prismatic structure was found to be an ideal energy absorption model. The buckling and extension analysis was further carried out to comprehensively study mechanical properties of the model with prismatic structure, showing that its first-order buckling load was 248.11 Mpa with little influence on the adjacent pixels. Conclusions Four mesomechanical models of the cancellous bone at different locations can be used as the mesomechanical model for energy absorption materials according to different mechanical properties, particularly as the mesomechanical model for the energy absorption sandwich composite material.