1.Puerarin attenuates angiotensin II-induced cardiac fibroblast proliferation via the promotion of catalase activity and the inhibition of hydrogen peroxide-dependent Rac-1 activation.
Gang CHEN ; Shi-Fen PAN ; Xiang-Li CUI ; Li-Hong LIU
Chinese Journal of Natural Medicines (English Ed.) 2018;16(1):41-52
		                        		
		                        			
		                        			The aims of the present study were to evaluate the effects of puerarin on angiotensin II-induced cardiac fibroblast proliferation and to explore the molecular mechanisms of action. Considering the role of HO in nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation, we hypothesized that modulating catalase activity would be a potential target in regulating the redox-sensitive pathways. Our results showed that the activation of Rac1 was dependent on the levels of intracellular HO. Puerarin blocked the phosphorylation of extracellular regulated protein kinases (ERK)1/2, abolished activator protein (AP)-1 binding activity, and eventually attenuated cardiac fibroblast proliferation through the inhibition of HO-dependent Rac1 activation. Further studies revealed that angiotensin II treatment resulted in decreased catalase protein expression and enzyme activity, which was disrupted by puerarin via the upregulation of catalase protein expression at the transcriptional level and the prolonged protein degradation. These findings indicated that the anti-proliferation mechanism of puerarin was mainly through blocking angiontensin II-triggered downregulation of catalase expression and HO-dependent Rac1 activation.
		                        		
		                        		
		                        		
		                        			Angiotensin II
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		                        			pharmacology
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		                        			Angiotensin II Type 1 Receptor Blockers
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		                        			pharmacology
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		                        			Animals
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		                        			Animals, Newborn
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		                        			Catalase
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		                        			genetics
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		                        			metabolism
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		                        			Cell Proliferation
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		                        			drug effects
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		                        			Cells, Cultured
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		                        			Extracellular Signal-Regulated MAP Kinases
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		                        			antagonists & inhibitors
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		                        			metabolism
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		                        			Fibroblasts
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		                        			Gene Expression Regulation
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		                        			drug effects
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		                        			Heart
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		                        			drug effects
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		                        			Hydrogen Peroxide
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		                        			metabolism
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		                        			pharmacology
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		                        			Isoflavones
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		                        			pharmacology
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		                        			Mice
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		                        			Myocardium
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		                        			cytology
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		                        			enzymology
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		                        			metabolism
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		                        			NADPH Oxidases
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		                        			antagonists & inhibitors
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		                        			metabolism
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		                        			Neuropeptides
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		                        			metabolism
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		                        			Signal Transduction
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		                        			drug effects
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		                        			Transcription Factor AP-1
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		                        			antagonists & inhibitors
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		                        			metabolism
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		                        			Transcriptional Activation
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		                        			drug effects
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		                        			rac1 GTP-Binding Protein
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		                        			metabolism
		                        			
		                        		
		                        	
2.Ultraviolet A Enhances Cathepsin L Expression and Activity via JNK Pathway in Human Dermal Fibroblasts.
Qing-Fang XU ; Yue ZHENG ; Jian CHEN ; Xin-Ya XU ; Zi-Jian GONG ; Yun-Fen HUANG ; Chun LU ; Howard I MAIBACH ; Wei LAI
Chinese Medical Journal 2016;129(23):2853-2860
BACKGROUNDCathepsin L (CatL) is a cysteine protease with strong matrix degradation activity that contributes to photoaging. Mannose phosphate-independent sorting pathways mediate ultraviolet A (UVA)-induced alternate trafficking of CatL. Little is known about signaling pathways involved in the regulation of UVA-induced CatL expression and activity. This study aims to investigate whether a single UVA irradiation affects CatL expression and activity and whether mitogen-activated protein kinase (MAPK)/activator protein-1 (AP-1) pathway is involved in the regulation of UVA-induced CatL expression and activity in human dermal fibroblasts (HDFs).
METHODSPrimary HDFs were exposed to UVA. Cell proliferation was determined by a cell counting kit. UVA-induced CatL production and activity were studied with quantitative real-time reverse transcription polymerase chain reaction (RT-PCR), Western blotting, and fluorimetric assay in cell lysates collected on three consecutive days after irradiation. Time courses of UVA-activated JNK and p38MAPK signaling were examined by Western blotting. Effects of MAPK inhibitors and knockdown of Jun and Fos on UVA-induced CatL expression and activity were investigated by RT-PCR, Western blotting, and fluorimetric assay. Data were analyzed by one-way analysis of variance.
RESULTSUVA significantly increased CatL gene expression, protein abundance, and enzymatic activity for three consecutive days after irradiation (F = 83.11, 56.14, and 71.19, respectively; all P < 0.05). Further investigation demonstrated phosphorylation of JNK and p38MAPK activated by UVA. Importantly, inactivation of JNK pathway significantly decreased UVA-induced CatL expression and activity, which were not affected by p38MAPK inhibition. Moreover, knockdown of Jun and Fos significantly attenuated basal and UVA-induced CatL expression and activity.
CONCLUSIONSUVA enhances CatL production and activity in HDFs, probably by activating JNK and downstreaming AP-1. These findings provide a new possible molecular approach for antiphotoaging therapy.
Anthracenes ; pharmacology ; Cathepsin L ; metabolism ; Cells, Cultured ; Child ; Child, Preschool ; Enzyme Inhibitors ; pharmacology ; Extracellular Signal-Regulated MAP Kinases ; antagonists & inhibitors ; Fibroblasts ; cytology ; drug effects ; metabolism ; radiation effects ; Humans ; Imidazoles ; pharmacology ; MAP Kinase Signaling System ; drug effects ; radiation effects ; Oncogene Proteins v-fos ; genetics ; metabolism ; Proto-Oncogene Proteins c-jun ; genetics ; metabolism ; Pyridines ; pharmacology ; Skin ; cytology ; Ultraviolet Rays
3.Extracellular signal-regulated kinase signaling pathway regulates the endothelial differentiation of periodontal ligament stem cells.
Hong ZHU ; Lankun LUO ; Ying WANG ; Jun TAN ; Peng XUE ; Qintao WANG
Chinese Journal of Stomatology 2016;51(3):154-159
OBJECTIVETo investigate the effect of extracellular signal-regulated kinase (ERK) signaling pathway on the endothelial differentiation of periodontal ligament stem cells (PDLSC).
METHODSHuman PDLSC was cultured in the medium with vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (b-FGF) to induce endothelial differentiation. Endothelial inducing cells was incubated with U0126, a specific p-ERK1/2 inhibitor. PDLSC from one person were randomly divided into four groups: control group, endothelial induced group, endothelial induced+DMSO group and endothelial induced+U0126 group. The protein expression of the p-EKR1/2 was analyzed by Western blotting at 0, 1, 3, 6 and 12 hours during endonthelial induction. The mRNA expressions of CD31, VE-cadherin, and VEGF were detected by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) after a 7-day induction. The proportion of CD31(+) to VE-cadherin(+) cells was identified by flow cytometry, and the ability of capillary-like tubes formation was detected by Matrigel assay after a 14-day induction. The measurement data were statistically analyzed.
RESULTSPhosphorylated ERK1/2 protein level in PDLSC was increased to 1.24±0.12 and 1.03±0.24 at 1 h and 3 h respectively, during the endothelial induction (P<0.01). The mRNA expressions of CD31 and VEGF in induced+U0126 group were decreased to 0.09±0.18 and 0.49±0.17, which were both significantly different with those in induced group (P<0.05). The proportion of CD31(+) to VE-cadherin(+) cells of induced+U0126 group were decreased to 5.22±0.85 and 3.56±0.87, which were both significantly different with those in induced group (P<0.05). In Matrigel assay, the branching points, tube number and tube length were decreased to 7.0±2.7, 33.5±6.4, and (15 951.0±758.1) pixels, which were all significantly different with those in induced group (P<0.05).
CONCLUSIONSThe endothelial differentiation of PDLSC is positively regulated by ERK signaling pathway. Inhibition of ERK1/2 phosphorylation could suppress endothelial differentiation of PDLSC.
Antigens, CD ; genetics ; metabolism ; Butadienes ; pharmacology ; Cadherins ; genetics ; metabolism ; Cell Differentiation ; Endothelial Cells ; cytology ; physiology ; Enzyme Inhibitors ; pharmacology ; Extracellular Signal-Regulated MAP Kinases ; physiology ; Fibroblast Growth Factor 2 ; pharmacology ; Humans ; Mitogen-Activated Protein Kinase 3 ; antagonists & inhibitors ; metabolism ; Nitriles ; pharmacology ; Periodontal Ligament ; cytology ; metabolism ; Phosphorylation ; Platelet Endothelial Cell Adhesion Molecule-1 ; genetics ; metabolism ; RNA, Messenger ; metabolism ; Random Allocation ; Signal Transduction ; Stem Cells ; cytology ; physiology ; Time Factors ; Vascular Endothelial Growth Factor A ; genetics ; metabolism ; pharmacology
4.Effects of estrogen on epidermis growth of mice and proliferation of human epidermal cell line HaCaT and its mechanism.
Tao ZHOU ; Jing CHEN ; Zongwei HUANG ; Li FANG ; Yu CHEN ; Yajie CHEN ; Yizhi PENG
Chinese Journal of Burns 2016;32(5):299-304
OBJECTIVETo observe the effects of estrogen on epidermis growth of mice and proliferation of keratinocytes (human epidermal cell line HaCaT), and to explore its mechanism.
METHODS(1) Five adult C57BL/6 mice in estrus cycle were identified by vaginal exfoliative cytology diagnosis and set as estrus group, while another 5 adult C57BL/6 mice with ovary resected before sexual development were set as ovariectomized group. The full-thickness skin from the tail root of mice in two groups were collected. The thickness of epidermis was observed and measured after HE staining. The distribution of proliferating cell nuclear antigen (PCNA)-positive cells in epidermis was observed by immunohistochemical staining, the number of which was counted. (2) HaCaT cells in logarithmic growth phase were cultured with RPMI 1640 nutrient solution containing 10% fetal bovine serum, and they were divided into negative control group (NC), pure estradiol group (PE), protein kinase B (Akt) inhibitor group (AI), and extracellular signal-regulated kinase (ERK) inhibitor group (EI) according to the random number table, with 20 wells in each group. To nutrient solution of each group, 1 μL dimethyl sulfoxide, 1 μL 17β-estradiol (100 nmol/L), 1 μL LY294002 (10 μmol/L), and 1 μL PD98059 (30 μmol/L) were added in group NC, group PE, group AI, and group EI respectively, and the last two groups were added with 1 μL 17β-estradiol (100 nmol/L) in addition. At post culture hour (PCH) 0 (immediately after culture), 24, 48, 72, 5 wells of cells from each group were collected to detect the proliferation activity of cells by cell counting kit 8 and microplate reader. (3) HaCaT cells in logarithmic growth phase were collected, grouped, and treated with the above-mentioned methods, with 3 wells in each group. At PCH 72, cell cycle distribution was detected by flow cytometer to calculate proliferation index (PI) of cells. (4) HaCaT cells in logarithmic growth phase were collected, grouped, and treated with the above-mentioned methods, with 3 dishes in each group. At PCH 72, the protein levels of phosphorylated Akt (p-Akt), phosphorylated ERK (p-ERK), and PCNA were determined with Western blotting. The cell experiments were repeated for 3 times. Data were processed with t test, one-way analysis of variance, analysis of variance of factorial design, and LSD test.
RESULTS(1) The epidermis thickness of mice in ovariectomized group was (33.5±3.0) μm, which was obviously thinner than that in estrus group [(51.4±3.1) μm, t=20.7, P<0.01]. The PCNA-positive cells mainly aggregated in the basal layer of epidermis of mice in two groups. The number of PCNA-positive cells in epidermis of mice in ovariectomized group was 37±12 per 200 fold visual field, obviously fewer than that in estrus group (96±15 per 200 fold visual field, t=15.3, P<0.01). (2) During PCH 0 to 48, there were no significant differences in the proliferation activity of cells between group PE and group NC (with P values above 0.05). At PCH 72, compared with that in group NC, the proliferation activity of cells in group PE was obviously increased (P<0.01). The proliferation activity of cells in groups AI and EI was obviously lower than that in the previous two groups (with P values below 0.01). (3) Compared with that in group NC [(51.6±1.1)%], the PI of cells in group PE was obviously increased [(58.5±0.8)%, P<0.05]. The PI values of cells in groups AI and EI were (34.9±0.8)% and (48.2±0.4)% respectively, both obviously lower than those in the previous two groups (with P values below 0.01). (4) Compared with that of group NC (0.566±0.034), the protein level of p-Akt in cells of group PE was significantly increased (1.048±0.077, P<0.01). Compared with that of group PE, the protein level of p-Akt was obviously decreased in cells of groups AI and EI (respectively 0.682±0.095 and 0.672±0.019, with P values below 0.01). Compared with that of group NC (0.469±0.013), the protein level of p-ERK obviously increased in cells of groups PE, AI, and EI (respectively 1.064±0.089, 1.010±0.038, 0.778±0.065, with P values below 0.01). The protein level of p-ERK in cells of group EI was obviously lower than that in group PE (P<0.01). Compared with that of group NC (0.386±0.053), the protein level of PCNA was obviously increased in cells of group PE (0.743±0.043, P<0.01). The protein levels of PCNA in cells of groups AI and EI were 0.264±0.019 and 0.223±0.065 respectively, both obviously lower than those in the previous two groups (with P values below 0.01).
CONCLUSIONSLack of estrogen damages the growth ability of epidermis of mice. Estrogen (17β-estradiol) can promote the proliferation of HaCaT cells by increasing the expression of PCNA via activating ERK/Akt signaling pathway.
Animals ; Cell Cycle ; Cell Line ; Cell Proliferation ; drug effects ; Epidermis ; cytology ; drug effects ; growth & development ; Estradiol ; pharmacology ; Extracellular Signal-Regulated MAP Kinases ; antagonists & inhibitors ; Female ; Humans ; Keratinocytes ; cytology ; drug effects ; Mice ; Mice, Inbred C57BL ; Phosphorylation ; Proliferating Cell Nuclear Antigen ; metabolism ; Proto-Oncogene Proteins c-akt ; antagonists & inhibitors ; Signal Transduction
5.Antiangiogenic Activity of Acer tegmentosum Maxim Water Extract in Vitro and in Vivo.
Eok Cheon KIM ; So Hun KIM ; Shan Ji PIAO ; Tack Joong KIM ; Kiho BAE ; Han Sung KIM ; Soon Sun HONG ; Byoung Ick LEE ; Moonsuk NAM
Journal of Korean Medical Science 2015;30(7):979-987
		                        		
		                        			
		                        			Angiogenesis, the formation of new blood vessels, is critical for tumor growth and metastasis. Notably, tumors themselves can lead to angiogenesis by inducing vascular endothelial growth factor (VEGF), which is one of the most potent angiogenic factors. Inhibition of angiogenesis is currently perceived as one of the most promising strategies for the blockage of tumor growth. In this study, we investigated the effects of Acer tegmentosum maxim water extract (ATME) on angiogenesis and its underlying signal mechanism. We studied the antiangiogenic activity of ATME by using human umbilical vein endothelial cells (HUVECs). ATME strongly inhibited VEGF-induced endothelial cell proliferation, migration, invasion, and tube formation, as well as vessel sprouting in a rat aortic ring sprouting assay. Moreover, we found that the p44/42 mitogen activated protein (MAP) kinase signaling pathway is involved in the inhibition of angiogenesis by ATME. Moreover, when we performed the in vivo matrigel plug assay, VEGF-induced angiogenesis was potently reduced when compared to that for the control group. Taken together, these results suggest that ATME exhibits potent antiangiogenic activity in vivo and in vitro and that these effects are regulated by the extracellular regulated kinase (ERK) pathway.
		                        		
		                        		
		                        		
		                        			Acer/*metabolism
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		                        			Angiogenesis Inhibitors/*pharmacology
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		                        			Animals
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		                        			Cell Line, Tumor
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		                        			Cell Movement/drug effects
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		                        			Cell Proliferation/drug effects
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		                        			Cell Survival
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		                        			Extracellular Signal-Regulated MAP Kinases/*metabolism
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		                        			Hep G2 Cells
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		                        			Human Umbilical Vein Endothelial Cells/*drug effects
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		                        			Humans
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		                        			MAP Kinase Signaling System/drug effects
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		                        			Mice
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		                        			Mice, Inbred C57BL
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		                        			Mitogen-Activated Protein Kinase 1/metabolism
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		                        			Neoplasm Invasiveness/pathology
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		                        			Neovascularization, Pathologic/*drug therapy/prevention & control
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		                        			Nitric Oxide Synthase Type III/metabolism
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		                        			Phosphorylation/drug effects
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		                        			Plant Extracts/pharmacology
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		                        			Rats
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		                        			Rats, Sprague-Dawley
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		                        			Transcription Factors/metabolism
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		                        			Vascular Endothelial Growth Factor A/antagonists & inhibitors/metabolism
		                        			
		                        		
		                        	
6.Effects and mechanisms of Qifu decoction ameliorating renal tubulointerstitial fibrosis through inhibiting ERK1/2 signaling pathway in unilateral ureteral obstruction rats with yang deficiency.
Wei SUN ; Xue-Jiao YIN ; Yue TU ; Yi-Gang WAN ; Hong LIU ; Hao HU
China Journal of Chinese Materia Medica 2014;39(21):4082-4089
OBJECTIVETo demonstrate the effects and mechanisms of Qifu decoction( QFD) on renal interstitial fibrosis (RIF) in model rats with yang-deficiency syndrome.
METHODThe rats were randomly divided into 3 groups, the Sham group (Group A), the Model group (Group B), the Qifu decoction group (Group C) and the Enalapril group (Group D). The RIF model was established by adenine administrated and unilateral ureteral obstruction (UUO) of the left ureter. After the model was successfully established, the rats in Group C and D were administrated with QFD or the Enalapril suspension,while the rats in Group A and B were administrated with distilled water. All rats were administrated for 3 weeks. Before administration and at the end of week 1, 2 and 3, the rats were weighted, and 24 h urinary protein excretion (Upro), urinary β2-microglobulin (Uβ2-MG) and urinary N-acetyl-D-glucosaminidase (NAG) were examined, respectively. All rats were killed after administration for 3 weeks. Blood and renal tissues were collected, renal morphology and tubulointerstitial morphology were evaluated, respectively. Serum cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), blood urea nitrogen (BUN), serum creatinine (Scr) and uric acid (UA) were detected, respectively. The protein expressions of E-cadherin, α-smooth muscle actin(α-SMA), transforming growth factor-β1 (TGF-β1), onnective tissue growth factor (CTGF) extracellular signal-regulated protein kinase 1/2(ERK1/2) and phosphorylated-ERK1/2 (p-ERK1/2) in kidney were evaluated, respectively.
RESULTQFD ameliorated serum cAMP level and the rate of cAMP/cGMP, attenuated urinary β2-MG level, NAG level and renal tubulointerstitial fibrosis, increased E-cadherin protein expression, and reduced α-SMA, TGF-β1, CTGF and p-ERK1/2 protein expressions in the kidney. However, QFD had no influence on renal function in vivo. In addition, these effects were better than those of the model rats treated by Enalapril.
CONCLUSIONQFD could alleviate yang-deficiency parameters, as well as urinary β2-MG level and NAG level in model rats induced by adenine administration and UUO. Moreover, QFD could improve EMT and RIF by up-regulating E-cadherin protein expression, and down-regulating α-SMA, TGF-β1, CTGF and p-ERK1/2 protein expressions, the key molecular in ERK1/2 signaling pathway.
Animals ; Drugs, Chinese Herbal ; pharmacology ; Extracellular Signal-Regulated MAP Kinases ; antagonists & inhibitors ; Fibrosis ; Kidney ; drug effects ; pathology ; Kidney Diseases ; drug therapy ; pathology ; MAP Kinase Signaling System ; drug effects ; Male ; Rats ; Rats, Sprague-Dawley ; Ureteral Obstruction ; complications ; Yang Deficiency ; complications
7.Phospholipase D inhibitor enhances radiosensitivity of breast cancer cells.
Ju Cheol SON ; Dong Woo KANG ; Kwang Mo YANG ; Kang Yell CHOI ; Tae Gen SON ; Do Sik MIN
Experimental & Molecular Medicine 2013;45(8):e38-
		                        		
		                        			
		                        			Radiation and drug resistance remain the major challenges and causes of mortality in the treatment of locally advanced, recurrent and metastatic breast cancer. Dysregulation of phospholipase D (PLD) has been found in several human cancers and is associated with resistance to anticancer drugs. In the present study, we evaluated the effects of PLD inhibition on cell survival, cell death and DNA damage after exposure to ionizing radiation (IR). Combined IR treatment and PLD inhibition led to an increase in the radiation-induced apoptosis of MDA-MB-231 metastatic breast cancer cells. The selective inhibition of PLD1 and PLD2 led to a significant decrease in the IR-induced colony formation of breast cancer cells. Moreover, PLD inhibition suppressed the radiation-induced activation of extracellular signal-regulated kinase and enhanced the radiation-stimulated phosphorylation of the mitogen-activated protein kinases p38 and c-Jun N-terminal kinase. Furthermore, PLD inhibition, in combination with radiation, was very effective at inducing DNA damage, when compared with radiation alone. Taken together, these results suggest that PLD may be a useful target molecule for the enhancement of the radiotherapy effect.
		                        		
		                        		
		                        		
		                        			Breast Neoplasms/*drug therapy/*enzymology/pathology
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		                        			Cell Death/drug effects/radiation effects
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		                        			Cell Line, Tumor
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		                        			Cell Proliferation/drug effects/radiation effects
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		                        			DNA Damage
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		                        			Enzyme Activation/drug effects/radiation effects
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		                        			Enzyme Inhibitors/*pharmacology/*therapeutic use
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		                        			Extracellular Signal-Regulated MAP Kinases/metabolism
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		                        			Female
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		                        			Humans
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		                        			JNK Mitogen-Activated Protein Kinases/metabolism
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		                        			Phospholipase D/*antagonists & inhibitors/metabolism
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		                        			Radiation Tolerance/*drug effects
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		                        			Radiation, Ionizing
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		                        			p38 Mitogen-Activated Protein Kinases/metabolism
		                        			
		                        		
		                        	
8.Potential molecular mechanisms of quercetin-induced heme oxygenase-1 in rat primary hepatocytes.
Wei LIU ; Shuang LIU ; Ping YAO ; Lie-gang LIU ; Hua QIN
Chinese Journal of Hepatology 2013;21(11):865-868
OBJECTIVETo investigate the possible molecular mechanisms of heme oxygenase-1 (HO-1) induction by quercetin using rat primary hepatocytes.
METHODSSprague-Dawley rat primary hepatocytes were isolated using a two-step collagenase perfusion technique and treated with quercetin at various doses (25 - 200 mumol/L) and times (2 - 12 h). To investigate the roles of various signaling pathways, the hepatocytes were pre-treated with 50 mumol/L quercetin plus an extracellular signal-regulated kinase (ERK) inhibitor (PD98059 at 10 mumol/L), a p38 inhibitor (SB203580 at 10 mumol/L), a c-Jun N-terminal kinase inhibitor (SP600125 at 10 mumol/L) or a phosphatidylinositol 3-kinase inhibitor (Wortmannin at 1 mumol/L) for 12 h. Changes in the mRNA and protein levels of HO-1 and nuclear factor, E-2 related factor 2 (Nrf2) were detected by RT-PCR and western blotting.
RESULTSAfter 4 - 12 h of treatment with quercetin at all concentrations, the HO-1 mRNA level in hepatocytes had increased significantly (vs. untreated control cells; all P less than 0.01). The quercetin-induced HO-1 expression and Nrf2 translocation into the nucleolus was inhibited by PD98059.
CONCLUSIONQuercetin may induce HO-1 expression via the ERK/Nrf2 signaling transduction pathway.
Animals ; Cells, Cultured ; Enzyme Inhibitors ; pharmacology ; Extracellular Signal-Regulated MAP Kinases ; antagonists & inhibitors ; Heme Oxygenase (Decyclizing) ; metabolism ; Hepatocytes ; drug effects ; metabolism ; NF-E2-Related Factor 2 ; metabolism ; Primary Cell Culture ; Quercetin ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; drug effects
9.Molecular mechanism of chemosensitization to paclitaxel in human melanoma cells induced by targeting the EGFR signaling pathway.
Xiao-jing ZHANG ; Liang ZHANG ; Yun-peng LIU ; Hui-mian XU ; Ping SUN ; Jin-gang SONG ; Ya-hong LUO
Chinese Journal of Oncology 2013;35(3):181-186
OBJECTIVETo study the molecular mechanism of epidermal growth factor receptor (EGFR) signaling pathway in mediating paclitaxel-resistance and improving paclitaxel sensitivity in human melanoma A375 cells.
METHODSHuman melanoma cell line A375 cells were treated with different concentrations of paclitaxel with or without 20 µmol/L AG1478 (EGFR inhibitor), 40 µmol/L PD98059 (extracellular signal conditioning kinase (ERK) 1/2 blockers) or 10 µmol/L LY294002 (PI3K inhibitor). MTT method was used to measure the proliferation of A375 cells. Flow cytometry was used to detect cell cycle and apoptosis in the A375 cells. The expressions of P-EGFR, P-ERK and P-AKT proteins were determined by Western blot analysis.
RESULTSPaclitaxel (0.001 µmol/L to 0.1 µmol/L) inhibited the growth of A375 cells (P < 0.01) and induced apoptosis (P < 0.05) in a dose- and time-dependent manner. AG1478 (20 µmol/L) increased the 0.01 µmol/L paclitaxel-induced inhibition rate from 38.5% to 62.6% at 72 h. Different doses of paclitaxel induced apoptosis in A375 cells by different ways, in which G0/G1 phase cells were decreased and mitotic phase was prolonged at 0.01 µmol/L, and cell cycle arrest at G2/M phase by 0.1 µmol/L paclitaxel. When DNA damage occurred in A375 cells exposed to paclitaxel, expression of P-EGFR, P-ERK and P-AKT proteins was increased. When EGFR signaling pathway was blocked, paclitaxel did not activate MAPK signaling pathway or PI3K/AKT signaling pathway and did not change its effect on cell cycle in vitro. When EGFR was inhibited by 20 µmol/L tyrophostin AG1478, the 0.001 and 0.01 µmol/L paclitaxel-induced early apoptosis rate in A375 cells was increased by 1.73- and 1.80-fold, respectively. When the ERK signaling was blocked by 40 µmol/L PD98059, the 0.001 and 0.01 µmol/L paclitaxel-induced early apoptosis rate in A375 cells was increased by 2.73- and 2.25-fold, respectively. When the AKT signaling was blocked by 10 µmol/L LY294002, the 0.001 and 0.01 µmol/L paclitaxel-induced early apoptosis rate in A375 cells was increased by 2.02- and 1.46-fold, respectively.
CONCLUSIONSHuman melanoma A375 cells produce resistance to paclitaxel (0.001 to 0.1 µmol/L) by activating MAPK signaling and PI3K/AKT signaling pathways. Targeting EGFR, ERK and AKT signaling pathways significantly enhances the cytotoxic effect of paclitaxel on human melanoma cells.
Antineoplastic Agents, Phytogenic ; administration & dosage ; pharmacology ; Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Chromones ; pharmacology ; Dose-Response Relationship, Drug ; Drug Resistance, Neoplasm ; Extracellular Signal-Regulated MAP Kinases ; antagonists & inhibitors ; metabolism ; Flavonoids ; pharmacology ; Humans ; Melanoma ; metabolism ; pathology ; Morpholines ; pharmacology ; Paclitaxel ; administration & dosage ; pharmacology ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Quinazolines ; pharmacology ; Receptor, Epidermal Growth Factor ; antagonists & inhibitors ; metabolism ; Signal Transduction ; drug effects ; Tyrphostins ; pharmacology
10.Roles of targeting Ras/Raf/MEK/ERK signaling pathways in the treatment of esophageal carcinoma.
Yu-Sui CHANG ; Ji-Chun LIU ; Hua-Qun FU ; Ben-Tong YU ; Shu-Bing ZOU ; Qi-Cai WU ; Li WAN
Acta Pharmaceutica Sinica 2013;48(5):635-641
		                        		
		                        			
		                        			Ras is best known for its ability to regulate cell growth, proliferation and differentiation. Mutations in Ras are associated with the abnormal cell proliferation which can result in incidence of all human cancers. Extracellular signal-regulated kinase (ERK) is a downstream effector of Ras and plays important roles in prognosis of tumors. Recently, evidence has gradually accumulated to demonstrate that there are other effectors between Ras and ERK, these proteins interact each other and constitute the thorough Ras/Raf/MEK/ERK signaling pathway. The pathway has profound effects on incidence of esophageal carcinoma and clinical applications of some chemotherapeutic drugs targeting the pathway. Further understanding of the relevant molecular mechanisms of Ras/Raf/MEK/ERK signaling pathway can be helpful for the development of efficient targeting therapeutic approaches which contribute to the treatment of esophageal cancer. In this article, roles of Ras/Raf/MEK/ERK signaling pathway in esophageal carcinoma as well as pharmacological targeting point in the pathway are reviewed.
		                        		
		                        		
		                        		
		                        			Animals
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		                        			Antineoplastic Agents
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		                        			pharmacology
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		                        			therapeutic use
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		                        			Carcinoma, Squamous Cell
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		                        			drug therapy
		                        			;
		                        		
		                        			enzymology
		                        			;
		                        		
		                        			pathology
		                        			;
		                        		
		                        			Cell Line, Tumor
		                        			;
		                        		
		                        			Enzyme Activation
		                        			;
		                        		
		                        			drug effects
		                        			;
		                        		
		                        			Esophageal Neoplasms
		                        			;
		                        		
		                        			drug therapy
		                        			;
		                        		
		                        			enzymology
		                        			;
		                        		
		                        			pathology
		                        			;
		                        		
		                        			Extracellular Signal-Regulated MAP Kinases
		                        			;
		                        		
		                        			antagonists & inhibitors
		                        			;
		                        		
		                        			metabolism
		                        			;
		                        		
		                        			Humans
		                        			;
		                        		
		                        			Mitogen-Activated Protein Kinase Kinases
		                        			;
		                        		
		                        			antagonists & inhibitors
		                        			;
		                        		
		                        			metabolism
		                        			;
		                        		
		                        			Proto-Oncogene Proteins c-raf
		                        			;
		                        		
		                        			antagonists & inhibitors
		                        			;
		                        		
		                        			metabolism
		                        			;
		                        		
		                        			Signal Transduction
		                        			;
		                        		
		                        			drug effects
		                        			;
		                        		
		                        			ras Proteins
		                        			;
		                        		
		                        			antagonists & inhibitors
		                        			;
		                        		
		                        			metabolism
		                        			
		                        		
		                        	
            
Result Analysis
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