Genistein is a high specific and noncompetitive inhibitor of epidermal growth factor receptor tyramine kinase domain (EGFR-TK). In the paper, a molecular docking between genistein and EGFR-TK was studied to explore the mechanism of their interaction and antitumor mechanism of genistein by AUTODOCK 3.05 program. The results indicated that genistein located in the active cavity of EGFR-TK by high affinity (deltaG = -31.2 kJ/mol), and genistein inhibited EGFR-TK by interfering with forming of Lys721/Glu738 ion pair. The inhibition belonged to noncompetitive interaction, in which hydrophobic force and hydrogen bond played key roles.
Catalytic Domain ; Genistein ; metabolism ; pharmacology ; Models, Molecular ; Receptor, Epidermal Growth Factor ; antagonists & inhibitors ; metabolism

OBJECTIVETo study the possible induction effect of exposure to 50 Hz magnetic field (MF) on clustering of cell membrane surface receptors for epidermal growth factor (EGF) and tumor necrosis factor (TNF), the starting site of signals of biological effects, and its possible intervention effect.

METHODSLung fibroblasts of Chinese hamster (CHL) were exposed to EGF, TNF, 0.4 mT 50 Hz MF, 0.4 mT noise MF, and 0.4 mT 50 Hz MF combined with 0.4 mT noise MF. Respectively, for different durations, following the treatment, EGF and TNF receptors on the cell membrane were marked by corresponding antibodies with immunohistochemical method, then observed under a confocal microscope.

RESULTSClustering of cell membrane receptors could be induced 5 min after treatment with EGF and TNF, as well as with 50 Hz MF at 0.4 mT, which reached the peak in 15 min. While noise MF with the same intensity did not induce clustering of cell membrane receptors. Superposition of noise MF with the same intensity could inhibit clustering of cell membrane receptors induced by 50 Hz MF.

CONCLUSIONClustering of EGF and TNF receptors on the cell membrane could be induced by 50 Hz MF, suggesting that membrane receptors would be one of the sites where MF signals coupled, and noise MF with the same intensity could inhibit these effects.

Animals ; Cell Line ; Cricetinae ; Electromagnetic Fields ; adverse effects ; Epidermal Growth Factor ; pharmacology ; Fibroblasts ; drug effects ; metabolism ; radiation effects ; Noise ; adverse effects ; Receptor, Epidermal Growth Factor ; metabolism ; Receptors, Cell Surface ; metabolism ; Receptors, Tumor Necrosis Factor ; metabolism ; Tumor Necrosis Factor-alpha ; pharmacology

OBJECTIVETo build 3D-pharmacophore model of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors using distance comparisons method and design novel EGFR inhibitors.

METHODSThirteen typical EGFR inhibitors were selected, and their biologically active conformations were obtained by using DOCK5.0 program, then 3D-pharmacophore model of EGFR inhibitors was built using distance comparisons method.

RESULTSValidation of the 3D-pharmacophore model was carried out and novel structures with potential inhibitory activity were selected by means of 3D-searching and docking method.

CONCLUSIONThis method can improve hit rate of lead compounds discovery and can be used to design novel EGFR inhibitors.

Drug Design ; Enzyme Inhibitors ; Epidermal Growth Factor ; metabolism ; Models, Chemical ; Protein-Tyrosine Kinases ; antagonists & inhibitors ; chemistry ; pharmacology ; Receptor, Epidermal Growth Factor ; antagonists & inhibitors ; chemistry ; Structure-Activity Relationship

OBJECTIVETo observe the effect of Tanshinone II A on the expression of epidermal growth facter (EGF) and epidermal growth facter recepter (EGFR) in human hepatocellular carcinoma cell line SMMC-7721.

METHODSThe human hepatocellular carcinoma SMMC-7721 cells cultured in vitro was treated with different concentrations of Tanshinone II A. The proliferation of the cells was measured by MTT assay, and the apoptosis of the cells was investigated by flow cytometry and cytochemical staining with Hoechst 33342. The expression of EGF and EGFR was detected by immunocytochemistry method. The levels of EGF in medium were measured by radioimmunoassay.

RESULTTanshinone II A inhibited the growth of SMMC-7721 cells remarkably in a dose-dependent manner. The inhibitory rate reached the peak (72.5%) after 0.5 microg/ml Tanshinone II A was used for 48 h, which was significantly higher than that in the controls (P<0.05). FCM analysis showed that when SMMC-7721 cells were treated with 0.5 microg/ml Tanshinone II A, the apoptosis rates for 24 h, 48 h and 72 h were (4.06+/-0.27)%, (7.58+/-0.56)% and (5.23+/-0.13)%, respectively which were markedly higher than those in the controls (all P<0.01). SMMC-7721 cell apoptosis with cell shrinkage, nuclear chromatin concentration and fragmentation as well as the formation of apoptotic bodies were observed by cytochemical staining when treated with Tanshinone II A. The immunocytochemistry showed that the expressions of EGF and EGFR were down regulated while the concentration of Tanshinone II A was increasing. The high expression rates for EGF and EGFR were 10%, 20%, respectively, and the gray scale was 181.52+/-1.63, 179.37+/-1.59, which were markedly higher than those in the controls (all P<0.05). The levels of EGF in medium measured by radioimmunoassay were decreased significantly after Tanshinone II A treatment.

CONCLUSIONTanshinone II A can inhibit cell proliferation and induce apoptosis in hepatocellular carcinoma cell line SMMC-7721, which may be related to the down-regulation of EGF and EGFR protein expression.

Antineoplastic Agents, Phytogenic ; pharmacology ; Apoptosis ; drug effects ; Carcinoma, Hepatocellular ; metabolism ; pathology ; Cell Line, Tumor ; Cell Proliferation ; Diterpenes, Abietane ; Down-Regulation ; drug effects ; Epidermal Growth Factor ; genetics ; metabolism ; Humans ; Liver Neoplasms ; metabolism ; pathology ; Phenanthrenes ; pharmacology ; Receptor, Epidermal Growth Factor ; genetics ; metabolism

AIMTo study the effect of the recombined human growth hormone(rhGH) on secretory immunoglobulin A (sIgA), epidermal growth factor (EGF) in rats with obstructive jaundice.

METHODSSixty Wistar rats were randomly divided into four groups, sham-operated (group A), common biliary duct-ligated (group B), biliary duct-ligated plus rhGH-treat for one week (group C), biliary duct-ligated plus rhGH-treat for two weeks (group D), each group had 15 rats. Except group A, the rats of other groups were operated with biliary duct-ligated. Until two weeks after operation, the rats of group A and B were killed. After operation, the rats of group C were treated with rhGH hypodermic injection (0.75 U x kg(-1) x d(-1)) for one week, and then killed. The rats of D group were treated with rhGH hypodermic injection (0.75 U x kg(-1) x d(-1)) for two weeks, and then killed. All procedures were performed aseptically. Total bilirubin (TB), alkaline phosphatase (ALP), prealbumin(PA), insulin-like growth factor (IGF-1), sIgA, EGF were measured.

RESULTSCompared with group A, in group B, C, D, serum level of PA, IGF-1 and sIgA, EGF level of gastric and intestinal juice were lower, but TB, ALP were higher, there were significant difference. Compared with group B, the rats with treatment of rhGH in group C and D had higher sIgA and EGF and lower intestinal bacterial translocation.

CONCLUSIONIn objective jaundice rats, rhGH can protect their hepatic function, intestinal physical-barrier function and immune-barrier function, and reduce intestinal bacterial translocation.

Animals ; Bacterial Translocation ; Epidermal Growth Factor ; metabolism ; Growth Hormone ; pharmacology ; Humans ; Immunoglobulin A, Secretory ; metabolism ; Jaundice, Obstructive ; metabolism ; Rats ; Rats, Wistar ; Recombinant Proteins ; pharmacology

OBJECTIVETo observe the effect of Chinese drugs of Jianpi Huayu (JPHY, strengthening Pi and dissolving stasis) on healing quality of gastric ulcer and its mechanism.

METHODSThe gastric ulcer model was established by subserous injection of ethanoic acid in rats. Rats were randomly divided into 4 groups, the blank group, the model group, the ranitidine (RT) group and the JPHY group. Quantity of regenerative mucosa of healed gastric ulcer was determined using HE stain, epidermal growth factor (EGF) content in serum and stomach mucosa was detected by RIA and epidermal growth factor receptor (EGFR) protein expression was determined by immunohistochemistry.

RESULTSThickness of regenerated mucosa in the CHM group was higher than that in the model group and the RT group (P<0.05 or P<0.01); EGF content in mucosa in the JPHY group and the RT group was higher than that in the model group (P<0.01) and EGFR protein expression in the JPHY group was higher than that in the model group (P<0.05).

CONCLUSIONJPHY could improve the proliferation of epithelial cells, inhibit gastric acid, improve microcirculation of gastric mucosa through the mediation of EGFR, so as to elevate the healing quality of gastric ulcer, display its anti-ulcer action.

Acetic Acid ; Animals ; Anti-Ulcer Agents ; pharmacology ; Drugs, Chinese Herbal ; pharmacology ; Epidermal Growth Factor ; metabolism ; Gastric Mucosa ; metabolism ; pathology ; physiopathology ; Male ; Random Allocation ; Rats ; Rats, Wistar ; Receptor, Epidermal Growth Factor ; metabolism ; Stomach Ulcer ; chemically induced ; physiopathology

BACKGROUND: Standard protocols are lacking for the preparation of platelet lysates (PL) as an alternative to using fetal bovine serum as a cell culture supplement. This study aimed to establish optimum conditions for preparing PL for use in cell cultures. METHODS: Cell density in three pooled platelet concentrates (PC) were adjusted to 1x10(12)/L and 2x10(12)/L. PL was prepared from PC by 1 to 3 freeze-thaw (FT) cycles. HaCaT cells were cultured in media supplemented with 5% or 10% PL. Cell numbers were estimated using a Cell Counting Kit-8 (CCK-8; Dojindo Laboratories, Japan). Growth factors were quantified by using the Luminex 200 system (Luminex Corporation, USA). RESULTS: Cell proliferation rates in the presence of PLs were similar when prepared from PCs of both cell densities. The rates were higher in media containing 5% PL than 10% PL when prepared by two FT cycles. Concentrations of vascular endothelial growth factor (VEGF), platelet-derived growth factor-AB/BB (PDGF-AB/BB), PDGF-AA, and epidermal growth factor (EGF) were significantly higher in PL prepared from PC with a cell density of 2x10(12)/L than 1x10(12)/L PC. However, only VEGF and PDGF-AA concentrations in PLs were correlated with HaCaT cell counts. CONCLUSIONS: The 5% PL from PC with a cell density of 1x10(12)/L prepared by two FT cycles treatment was the most effective condition that supported steady HaCaT cell proliferation. Our finding may be useful for preparing PL-supplemented cell culture media.
Blood Platelets/chemistry/*metabolism ; Cell Line ; Cell Proliferation/drug effects ; Culture Media/pharmacology ; Epidermal Growth Factor/chemistry/pharmacology ; Humans ; Platelet-Derived Growth Factor/chemistry/pharmacology ; Vascular Endothelial Growth Factor A/chemistry/pharmacology

After binding to its ligand, epidermal growth factor receptor (EGFR) dimerizes and is autophosphorylated. These events initiate the signal transduction process, which regulates a plethora of biologic activity. The duration and strength of these signals are controlled by many regulatory mechanisms, including downregulating activated EGFR primarily via endocytosis and ubiquitination-dependent lysomal degradation. The interaction between EGFR and the ubiquitin ligase Cbl/adaptor protein CIN85, as well as ESCRT complex recruitment play important roles in the process of downregulating EGFR. Tumorigenesis results when the de-sensitization process of EGFR is halted by its own mutation or a mutation that abrogates Cbl E3 ligase activity.
Adaptor Proteins, Signal Transducing ; metabolism ; Animals ; Down-Regulation ; Endocytosis ; Epidermal Growth Factor ; pharmacology ; Humans ; Mutation ; Proto-Oncogene Proteins c-cbl ; metabolism ; Receptor, Epidermal Growth Factor ; genetics ; metabolism ; Signal Transduction ; Ubiquitin ; metabolism

This experiment was designed to study the effect of 131I-recombinant human epidermal growth factor (131I-rhEGF) on the growth of tumor in nude mice loaded with human breast cancer. Bioactivity of 131I-rhEGF and uptake of 131I-rhEGF in breast cancer tissue were verified using biodistribution experiment of 131I-rhEGF in the nude mice loaded with human breast cancer. The effect of 131I-rhEGF on the growth of tumor was assessed via the growth experiment of tumor in the nude mice loaded with human breast cancer. The ultrastructural change of the tumor cell treated with 131I-rhEGF was observed under transmission electron microscope, and the pathological change of the tumor tissue treated with 131I-rhEGF was detected by biopsy. The results showed that the tumor tissue of nude mice bearing human breast cancer obviously takes in 131I-rhEGF; that intravenous administration and intratumoral administration of 131I-rhEGF both obviously inhibit the growth of tumor, the inhibition rates (82.00% and 80.70%) being remarkably higher than that of 131I (7.49%) and that of 131I-HSA (6.91%) (P<0.05); and that intravenous and intratumoral administration of 131I-rhEGF both obviously damage and kill tumor cells. Therefore, 131I-rhEGF can inhibit the growth of human breast cancer cell in nude mice; it is a potential receptor-mediated radioactivity targeting drug for treating breast cancer.
Animals ; Breast Neoplasms ; pathology ; ultrastructure ; Drug Delivery Systems ; Epidermal Growth Factor ; biosynthesis ; genetics ; pharmacology ; Female ; Humans ; Iodine Radioisotopes ; administration & dosage ; pharmacology ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Neoplasm Transplantation ; Receptor, Epidermal Growth Factor ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics ; pharmacology

A visible cutaneous scar develops from the excess formation of immature collagen in response to an inflammatory reaction. This study examined the role of epidermal growth factor (EGF) in the formation of cutaneous scars. Twenty Crl:CD-1 (ICR) mice were used and 2 full-thickness skin wounds were made on the dorsum of each mouse. One of the wounds was treated with recombinant human EGF by local application and the other was treated with saline for control until complete healing was achieved. The EGF-treated group's wounds healed faster than the control group's. The width of the scar was smaller by 30% and the area was smaller by 26% in the EGF-treated group. Inflammatory cell numbers were significantly lower in the EGF-treated group. The expression of transforming growth factor (TGF)-beta1 in the EGF-treated group was increased. It was observed that the amount of collagen in the EGF-treated group was larger than the control group. In the EGF-treated group, the visible external scars were less noticeable than that in the control group. These results suggest that EGF can reduce cutaneous scars by suppressing inflammatory reactions, decreasing expression of TGF-beta1, and mediating the formation of collagen.
Animals ; Cicatrix/pathology/*prevention & control ; Collagen/metabolism ; Epidermal Growth Factor/*pharmacology ; Humans ; Inflammation/metabolism ; Mice ; Recombinant Proteins/*pharmacology ; Skin/drug effects/metabolism/pathology ; Wound Healing/*drug effects