1.Role of SWI/SNF Chromatin Remodeling Complex in Tumor Drug Resistance
Gui-Zhen ZHU ; Qiao YE ; Yuan LUO ; Jie PENG ; Lu WANG ; Zhao-Ting YANG ; Feng-Sen DUAN ; Bing-Qian GUO ; Zhu-Song MEI ; Guang-Yun WANG
Progress in Biochemistry and Biophysics 2025;52(1):20-31
Tumor drug resistance is an important problem in the failure of chemotherapy and targeted drug therapy, which is a complex process involving chromatin remodeling. SWI/SNF is one of the most studied ATP-dependent chromatin remodeling complexes in tumorigenesis, which plays an important role in the coordination of chromatin structural stability, gene expression, and post-translation modification. However, its mechanism in tumor drug resistance has not been systematically combed. SWI/SNF can be divided into 3 types according to its subunit composition: BAF, PBAF, and ncBAF. These 3 subtypes all contain two mutually exclusive ATPase catalytic subunits (SMARCA2 or SMARCA4), core subunits (SMARCC1 and SMARCD1), and regulatory subunits (ARID1A, PBRM1, and ACTB, etc.), which can control gene expression by regulating chromatin structure. The change of SWI/SNF complex subunits is one of the important factors of tumor drug resistance and progress. SMARCA4 and ARID1A are the most widely studied subunits in tumor drug resistance. Low expression of SMARCA4 can lead to the deletion of the transcription inhibitor of the BCL2L1 gene in mantle cell lymphoma, which will result in transcription up-regulation and significant resistance to the combination therapy of ibrutinib and venetoclax. Low expression of SMARCA4 and high expression of SMARCA2 can activate the FGFR1-pERK1/2 signaling pathway in ovarian high-grade serous carcinoma cells, which induces the overexpression of anti-apoptosis gene BCL2 and results in carboplatin resistance. SMARCA4 deletion can up-regulate epithelial-mesenchymal transition (EMT) by activating YAP1 gene expression in triple-negative breast cancer. It can also reduce the expression of Ca2+ channel IP3R3 in ovarian and lung cancer, resulting in the transfer of Ca2+ needed to induce apoptosis from endoplasmic reticulum to mitochondria damage. Thus, these two tumors are resistant to cisplatin. It has been found that verteporfin can overcome the drug resistance induced by SMARCA4 deletion. However, this inhibitor has not been applied in clinical practice. Therefore, it is a promising research direction to develop SWI/SNF ATPase targeted drugs with high oral bioavailability to treat patients with tumor resistance induced by low expression or deletion of SMARCA4. ARID1A deletion can activate the expression of ANXA1 protein in HER2+ breast cancer cells or down-regulate the expression of progesterone receptor B protein in endometrial cancer cells. The drug resistance of these two tumor cells to trastuzumab or progesterone is induced by activating AKT pathway. ARID1A deletion in ovarian cancer can increase the expression of MRP2 protein and make it resistant to carboplatin and paclitaxel. ARID1A deletion also can up-regulate the phosphorylation levels of EGFR, ErbB2, and RAF1 oncogene proteins.The ErbB and VEGF pathway are activated and EMT is increased. As a result, lung adenocarcinoma is resistant to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs). Although great progress has been made in the research on the mechanism of SWI/SNF complex inducing tumor drug resistance, most of the research is still at the protein level. It is necessary to comprehensively and deeply explore the detailed mechanism of drug resistance from gene, transcription, protein, and metabolite levels by using multi-omics techniques, which can provide sufficient theoretical basis for the diagnosis and treatment of poor tumor prognosis caused by mutation or abnormal expression of SWI/SNF subunits in clinical practice.
2.Exploring anti-inflammatory mechanism of urolithin A based on miRNA155-5p-mediated MAPK/NF-κB pathway
TUOHUDAALI WU-LI-PAN ; Yuan SUN ; Wan-Ting DING ; Jun ZHAO
Chinese Pharmacological Bulletin 2024;40(6):1066-1074
Aim To explore anti-inflammatory mecha-nism of urolithin A(Uro A)based on the miRNA155-5p-regulated MAPK/NF-κB pathway in a lipopolysac-charide(LPS)-stimulated RAW264.7 inflammatory cell model.Methods The mRNA expression of miR-15-5p,p38 MAPK,JNK and ERK was detected by transfection of overexpression of miR-155-5p-mimics and miR-NC into LPS-induced RAW264.7 cells,and the miR-15-5p,p38 MAPK,JNK,and ERK mRNA expressions in the cells were detected by RT-qPCR.The effect of Uro A on cell viability was detected by MTT assay.The NO content in cell supernatant was detected by Griess assay.The cell supernatant PGE2,IL-6,IL-1 β and TNF-α expression levels were detec-ted by ELISA.The iNOS,COX-2,TLR4,and the MAPK/NF-κB pathway-related protein expression lev-els were detected by Western blot.Results The p38 MAPK,JNK and ERK mRNA expression levels were significantly higher in the miRNA155-5p overexpres-sion group than those in the miR-NC group(P<0.01).Compared with the model group,Uro A signif-icantly inhibited miRNA155-5p,NO,PGE2,TNF-α,IL-1β,and IL-6 levels(P<0.01)as well as de-creased the expression levels of iNOS and COX-2 pro-teins(P<0.01)in a concentration-dependent man-ner.Moreover,Uro A could significantly inhibit the expression levels of TLR4 protein and the expression levels of phosphorylation levels of p38 MAPK,JNK,NF-κB p65,and IκBα proteins in LPS irritated RAW264.7 cells(P<0.05).However,Uro A did not show a significant inhibitory effect on ERK1/2 pro-tein phosphorylation.Conclusion Uro A could signif-icantly inhibit LPS-induced inflammatory response,and its mechanism may be related to miRNA155-5p-mediated TLR4/MAPK/NF-κB signaling pathway.
3.Effect of DDR1 on high glucose induced endothelial dysfunction by regulating NF-κB/NLRP3 mediated pyroptosis
Wei-Chen ZHAO ; Chun-Yuan HE ; Zong-Biao ZHAO ; Feng-Sen ZHANG ; Yi-Miao XIA ; Fa-Cai WANG ; Ting-Ting LI
Chinese Pharmacological Bulletin 2024;40(12):2325-2332
Aim To investigate the effect of discoidin domain receptor 1(DDR1)on high glucose induced endothelial cell dysfunction and the underlying mecha-nism.Methods Human umbilical vein endothelial cells(HUVECs)were cultured in vitro and divided in-to the control group and high glucose induction group(HG).HUVECs were treated with 33 mmol·L-1 D-glucose for 48 hours to construct endothelial dysfunc-tion.Pyroptosis was detected using propidium iodide staining(PI);lactate dehydrogenase(LDH)and IL-1β,IL-18 levels were determined using enzyme linked immunosorbent assay(ELISA);the expression of DDR1 and NF-κB/NLRP3 signaling pathway proteins and pyroptosis related proteinses were detected using Western blot.Subsequently,the experiment was divid-ed into the control group,HG group,HG+DDR1 NC group,and HG+DDR1 siRNA group.The effect of high glucose on the proliferation and migration of HU-VECs was observed after transfection with DDR1 siR-NA for 24 hours;ELISA was used to detect the endo-thelial nitric oxide synthase(eNOS),vascular cell ad-hesion molecule-1(VCAM-1),intercellular adhesion molecule-1(ICAM-1),as well as LDH,IL-1β,IL-18 levels;PI was employed to detect pyroptosis;Western blot was applied to detect DDR1 and NF-κB/NLRP3 signaling pathway proteins and pyroptosis related pro-teins.Results Compared with the control group,HG group decreased eNOS content,increased VCAM-1 and ICAM-1 contents,decreased cell viability and migration ability,and significantly increased the expressions of DDR1,p-NF-κB,NLRP3 and pyroptosis related pro-teins.The levels of LDH,IL-1β,IL-18 and the rate of pyroptosis significantly increased(P<0.05).Com-pared with HG group,DDR1 siRNA could promote the secretion of eNOS,decrease the levels of VCAM-1,ICAM-1,LDH,IL-1β and IL-1 8,increase cell viability and migration ability,reduce the expression of p-NF-κB,NLRP3 and pyroptosis related proteins,and inhibit high glucose-induced pyroptosis of HUVECs(P<0.05).Conclusions Gene silencing DDR1 can im-prove vascular endothelial cell dysfunction induced by high glucose,and the mechanism is related to the inhi-bition of NF-κB/NLRP3 signaling pathway mediated pyroptosis.
4.Effects of Danggui Buxue Decoction on myocardial ferroptosis in a rat model of heart failure with preserved ejection fraction
Ting JIA ; Dan QI ; Jing MA ; Huan LIU ; Jing ZHAO ; Song-Yan XUE ; Fang-Yuan WANG
Chinese Traditional Patent Medicine 2024;46(11):3629-3635
AIM To observe the effects of Danggui Buxue Decoction on myocardial ferroptosis in a rat model of heart failure with preserved ejection fraction(HFpEF).METHODS The rats were randomly divided into the control group,the model group and the Danggui Buxue Decoction group.After 8 weeks feeding of 8%high-salt diet in the model and trial groups to induce the rats into HFpEFd models,rats of the Danggui Buxue Decoction group were given 4 g/kg Danggui Buxue Decoction once daily for 4 weeks,in contrast to those of the control group given 12 weeks feeding of 0.3%low-salt diet.The rats had their left ventricular ejection fraction(LVEF),left ventricular fraction shortening(LVFS),left ventricular end-diastolic diameter(LVIDD),and end-diastolic left ventricular posterior wall thickness(LVPWd)detected by echocardiography;their pathological changes of myocardial tissue by HE and Masson staining;their myocardial mitochondrial morphology observed by transmission electron microscopy;their serum BNP,NT-proBNP levels,myocardial tissue Fe3+levels,and their levels of ROS,MDA,LPO and GSH,and SOD activity in serum and myocardium detected by ELISA method;and their myocardial expressions of ferroptosis marker proteins GPX4,FTH1 and xCT detected by immunofluorescence staining and Western blot method.RESULTS Compared with the model group,the Danggui Buxuetang group displayed increased LVEF,LVFS(P<0.01);decreased LVIDD,LVPWd(P<0.05,P<0.01);decreased serum BNP,NT-proBNP levels(P<0.01);decreased myocardial Fe3+level(P<0.01);decreased MDA,ROS and LPO levels in serum and myocardium(P<0.01);increased GSH level and SOD activity(P<0.01);and increased expressions of myocardial ferroptosis related protein GPX4,FTH1 and xCT(P<0.05,P<0.01).CONCLUSION Danggui Buxue Decoction protects the cardiac function of the rat model of HFpEF through inhibiting the occurrence of myocardial ferroptosis and reducing the myocardial oxidative stress level as well.
5.Hapln1 promotes dedifferentiation and proliferation of iPSC-derived cardiomyocytes by promoting versican-based GDF11 trapping
Hao DING-JUN ; Qin YUE ; Zhou SHI-JIE ; Dong BU-HUAI ; Yang JUN-SONG ; Zou PENG ; Wang LI-PING ; Zhao YUAN-TING
Journal of Pharmaceutical Analysis 2024;14(3):335-347
Hyaluronan and proteoglycan link protein 1(Hapln1)supports active cardiomyogenesis in zebrafish hearts,but its regulation in mammal cardiomyocytes is unclear.This study aimed to explore the potential regulation of Hapln1 in the dedifferentiation and proliferation of cardiomyocytes and its therapeutic value in myocardial infarction with human induced pluripotent stem cell(hiPSC)-derived car-diomyocytes(CMs)and an adult mouse model of myocardial infarction.HiPSC-CMs and adult mice with myocardial infarction were used as in vitro and in vivo models,respectively.Previous single-cell RNA sequencing data were retrieved for bioinformatic exploration.The results showed that recombinant human Hapln1(rhHapln1)promotes the proliferation of hiPSC-CMs in a dose-dependent manner.As a physical binding protein of Hapln1,versican interacted with Nodal growth differentiation factor(NODAL)and growth differentiation factor 11(GDF11).GDF11,but not NODAL,was expressed by hiPSC-CMs.GDF11 expression was unaffected by rhHapln1 treatment.However,this molecule was required for rhHapln1-mediated activation of the transforming growth factor(TGF)-β/Drosophila mothers against decapentaplegic protein(SMAD)2/3 signaling in hiPSC-CMs,which stimulates cell dedifferentiation and proliferation.Recombinant mouse Hapln1(rmHapln1)could induce cardiac regeneration in the adult mouse model of myocardial infarction.In addition,rmHapln1 induced hiPSC-CM proliferation.In conclusion,Hapln1 can stimulate the dedifferentiation and proliferation of iPSC-derived cardiomyocytes by promoting versican-based GDF11 trapping and subsequent activation of the TGF-β/SMAD2/3 signaling pathway.Hapln1 might be an effective hiPSC-CM dedifferentiation and proliferation agent and a po-tential reagent for repairing damaged hearts.
6.A multi-center epidemiological study on pneumococcal meningitis in children from 2019 to 2020
Cai-Yun WANG ; Hong-Mei XU ; Gang LIU ; Jing LIU ; Hui YU ; Bi-Quan CHEN ; Guo ZHENG ; Min SHU ; Li-Jun DU ; Zhi-Wei XU ; Li-Su HUANG ; Hai-Bo LI ; Dong WANG ; Song-Ting BAI ; Qing-Wen SHAN ; Chun-Hui ZHU ; Jian-Mei TIAN ; Jian-Hua HAO ; Ai-Wei LIN ; Dao-Jiong LIN ; Jin-Zhun WU ; Xin-Hua ZHANG ; Qing CAO ; Zhong-Bin TAO ; Yuan CHEN ; Guo-Long ZHU ; Ping XUE ; Zheng-Zhen TANG ; Xue-Wen SU ; Zheng-Hai QU ; Shi-Yong ZHAO ; Lin PANG ; Hui-Ling DENG ; Sai-Nan SHU ; Ying-Hu CHEN
Chinese Journal of Contemporary Pediatrics 2024;26(2):131-138
Objective To investigate the clinical characteristics and prognosis of pneumococcal meningitis(PM),and drug sensitivity of Streptococcus pneumoniae(SP)isolates in Chinese children.Methods A retrospective analysis was conducted on clinical information,laboratory data,and microbiological data of 160 hospitalized children under 15 years old with PM from January 2019 to December 2020 in 33 tertiary hospitals across the country.Results Among the 160 children with PM,there were 103 males and 57 females.The age ranged from 15 days to 15 years,with 109 cases(68.1% )aged 3 months to under 3 years.SP strains were isolated from 95 cases(59.4% )in cerebrospinal fluid cultures and from 57 cases(35.6% )in blood cultures.The positive rates of SP detection by cerebrospinal fluid metagenomic next-generation sequencing and cerebrospinal fluid SP antigen testing were 40% (35/87)and 27% (21/78),respectively.Fifty-five cases(34.4% )had one or more risk factors for purulent meningitis,113 cases(70.6% )had one or more extra-cranial infectious foci,and 18 cases(11.3% )had underlying diseases.The most common clinical symptoms were fever(147 cases,91.9% ),followed by lethargy(98 cases,61.3% )and vomiting(61 cases,38.1% ).Sixty-nine cases(43.1% )experienced intracranial complications during hospitalization,with subdural effusion and/or empyema being the most common complication[43 cases(26.9% )],followed by hydrocephalus in 24 cases(15.0% ),brain abscess in 23 cases(14.4% ),and cerebral hemorrhage in 8 cases(5.0% ).Subdural effusion and/or empyema and hydrocephalus mainly occurred in children under 1 year old,with rates of 91% (39/43)and 83% (20/24),respectively.SP strains exhibited complete sensitivity to vancomycin(100% ,75/75),linezolid(100% ,56/56),and meropenem(100% ,6/6).High sensitivity rates were also observed for levofloxacin(81% ,22/27),moxifloxacin(82% ,14/17),rifampicin(96% ,25/26),and chloramphenicol(91% ,21/23).However,low sensitivity rates were found for penicillin(16% ,11/68)and clindamycin(6% ,1/17),and SP strains were completely resistant to erythromycin(100% ,31/31).The rates of discharge with cure and improvement were 22.5% (36/160)and 66.2% (106/160),respectively,while 18 cases(11.3% )had adverse outcomes.Conclusions Pediatric PM is more common in children aged 3 months to under 3 years.Intracranial complications are more frequently observed in children under 1 year old.Fever is the most common clinical manifestation of PM,and subdural effusion/emphysema and hydrocephalus are the most frequent complications.Non-culture detection methods for cerebrospinal fluid can improve pathogen detection rates.Adverse outcomes can be noted in more than 10% of PM cases.SP strains are high sensitivity to vancomycin,linezolid,meropenem,levofloxacin,moxifloxacin,rifampicin,and chloramphenicol.[Chinese Journal of Contemporary Pediatrics,2024,26(2):131-138]
7.Clinical Study on the Treatment of Advanced Liver Cancer of Qi Deficiency and Toxic Stasis Type by Jiawei Yupingfeng San
Zongao WANG ; Minghui ZHANG ; Hua SUN ; Yiran OUYANG ; Lanmei ZHAO ; Ting ZHANG ; Fei YAO ; Qin YUAN ; Guorong JIANG ; Lurong ZHANG ; Min LIU
Journal of Nanjing University of Traditional Chinese Medicine 2024;40(4):413-418
OBJECTIVE To observe the clinical efficacy and effect on serum thymic stromal lymphopoietin(TSLP)levels of pa-tients with advanced liver cancer of qi deficiency and toxic stasis type by Jiawei Yupingfeng San.METHODS Using random double blind method,120 patients with advanced liver cancer of qi deficiency and toxic stasis type were randomly divided into 3 groups:Jiawei Yupingfeng San group,Yupingfeng San group,and placebo group,each consisting of 40 cases.All patients in the 3 groups were given conventional treatment such as radiotherapy,chemotherapy,interventional or targeted therapy;Jiawei Yupingfeng San group was given Jiawei Yupingfeng San granules,Yupingfeng San group was given Yupingfeng San granules,and placebo group was given placebo.The course of treatment was 2 months.The changes of Karnofsky functional status score(KPS score),TCM syndrome score,tumor size and serum TSLP level in the 3 groups were observed before and after treatment,and the correlation between the changes of tumor size and TSLP was analyzed.RESULTS After treatment,the KPS scores of Yupingfeng San group and Jiawei Yupingfeng San group were sig-nificantly increased(P<0.05,P<0.01),TCM syndrome score were decreased(P<0.01),tumor growth(P<0.05,P<0.01)was de-layed,and serum TSLP levels(P<0.05,P<0.01)were decreased.Furthermore,there was a slight positive correlation between chan-ges in tumor size and changes in TSLP(P<0.05).In terms of improving tumor size,the curative effect of Jiawei Yupingfeng San group was better than that of Yupingfeng San group(P<0.05).During the treatment period,no obvious adverse reactions were observed in the 3 groups of patients.CONCLUSION Combined with conventional treatment,Jiawei Yupingfeng San can significantly delay tumor growth in patients with advanced liver cancer of qi deficiency and toxic stasis type and improve patients'TCM syndromes and their qual-ity of survival.The therapeutic mechanism is related to reducing the expression of serum TSLP and improving the immune status of pa-tients,thereby delaying the growth of tumors.
8.Precise application of Beichaihu and Nanchaihu in classical formulas.
Yu-Ping SHE ; Pei-Pei ZHANG ; Jing-Yan HU ; Yong-Hua GUO ; Qian CAO ; Xiang YIN ; Xiu-Hua HU ; Ting ZHAO ; Feng-Bo LIU ; Yuan ZHANG ; Sheng-Li WEI
China Journal of Chinese Materia Medica 2023;48(3):681-688
To maintain the precision and stability of the efficacy of classical formulas, this study compared the origins and specifications of Bupleuri Radix and revealed the precise application regularity of Bupleurum chinense(Beichaihu) and Bupleurum scorzonerifolium(Nanchaihu) in classical formulas. The efficacy and indications of formulas with Bupleuri Radix as the sovereign drug in the Treatise on Cold Damage and Miscellaneous Diseases(Shang Han Za Bing Lun) were investigated. The difference in the efficacy of Bupleuri Radix as well as the differences in the chemical composition, and liver-protecting and lipid-lowering effects of the decoctions of Beichaihu and Nanchaihu were analyzed with LC-MS technology based on the CCl_4-induced liver injury model in mice and sodium oleate-induced HepG2 hyperlipidemia cell model. The results showed that seven classical formulas with Bupleuri Radix as the sovereign drug in the Treatise on Cold Damage and Miscellaneous Diseases were mainly used in the treatment of digestive, metabolic, immune, circulatory, and other diseases. Bupleuri Radix mainly played the functions of protecting the liver, benefiting the gallbladder, and lowering the lipid, and had different focuses in different formulas. There were 14 differential components in the decoctions of Beichaihu and Nanchaihu, and the chemical structures of 11 components were identified, including 10 saponins and one flavonoid. The results of the liver-protecting efficacy experiment showed that compared with the Nanchaihu decoction, Beichaihu decoction could reduce the serum aspartate aminotransferase(AST) activity in liver injury model mice(P<0.01). The results of the lipid-lowering efficacy experiment proved that Beichaihu and Nanchaihu decoctions both showed highly significant differences in lowering the total cholesterol(TC) and triglyceride(TG) content in HepG2 cells(P<0.01), and Nanchaihu decoction was superior to Beichaihu decoction in lowering the lipid. The results of this study preliminarily proved that there were differences in chemical composition, and liver-protecting and lipid-lowering effects of Beichaihu and Nanchaihu decoctions, indicating that it was necessary to determine the precise origin of Bupleuri Radix in the clinical formulation of traditional Chinese medicine. The study provides a scientific basis for both precise clinical medication and purpose-based accurate quality evaluation of traditional Chinese medicine in clinical application.
Animals
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Mice
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Liver
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Aspartate Aminotransferases
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Bupleurum
9.Effects of Buyang Huanwu Decoction on Intestinal Barrier, Intestinal Flora, and Trimethylamine Oxide in Rats with Heart Failure.
Jie-Qiong WENG ; Jie-Bai LI ; Meng-Fei YUAN ; Ting-Ting YAO ; Jing-Fang ZHANG ; Yuan-Yuan ZENG ; Jing ZHAO ; Ying LI ; Ke XU ; Xiao-Xu SHEN
Chinese journal of integrative medicine 2023;29(2):155-161
OBJECTIVE:
To explore the mechanisms of Buyang Huanwu Decoction (BYHWD) modulating the gut microbiome and trimethylamine oxide (TAMO) to exert cardioprotective effects.
METHODS:
Ligation of the left anterior descending coronary artery was performed in rats to induce heart failure (HF). Except for the sham-operation group (n=10), 36 operation-induced models were randomized into 3 groups using a random number table (n=12 in each group): the model group, the BYHWD group (15.02 g/kg BYHWD), and the positive group (4.99 g/kg metoprolol succinate). After 4-week treatment (once daily by gavage), echocardiography was applied to evaluate the cardiac function and the Tei index (the ratio of ventricular isovolumic contraction time (IVCT) and isovolumic diastolic time (IVRT) to ejection time (ET)) was calculated; hematoxylin-eosin (HE) staining was observed to characterize the pathology of the myocardium and small intestinal villi. D-lactic acid was detected by an enzyme-linked immunosorbent assay (ELISA). Expressions of occludin, claudin-1, and zonula occludens (ZO-1) were detected by Western blot. 16S ribosomal ribonucleic acid (16S rRNA) sequencing was used to explore the changes in the intestinal flora. TMAO was detected via liquid chromatography-tandem mass spectrometry (LC-MS/MS).
RESULTS:
In the echocardiography, the Tei index was considerably lower in the positive and BYHWD groups compared with the model group (P<0.05). Besides, BYHWD improved the pathology of myocardium and small intestine of HF rats and lowered the D-lactic acid content in the serum, when compared with the model group (P<0.05). BYHWD also improved the expression of occludin and claudin-1 (P<0.05); in the gut microbiota analysis, BYHWD slowed down modifications in the structure distribution of gut microbiota and regulated the diversity of intestinal flora in HF rats. The content of TMAO in the serum was significantly lowered by BYWHT compared with the model group (P<0.05).
CONCLUSION
BYHWD may delay progression of HF by enhancing the intestinal barrier structure, and regulating intestinal flora and TAMO.
Rats
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Animals
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Rats, Sprague-Dawley
;
Gastrointestinal Microbiome
;
Chromatography, Liquid
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Claudin-1
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Occludin
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RNA, Ribosomal, 16S
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Tandem Mass Spectrometry
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Drugs, Chinese Herbal/pharmacology*
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Heart Failure
10. The differential effect of AICAR on c-Myc expression and proliferation in specific tumor cell lines
Yan-Li ZHAO ; Man SHANG ; Ting WANG ; Yuan FU
Chinese Pharmacological Bulletin 2023;39(12):2288-2295
Aim To investigate the effect of AICAR on the expression of the proto-oncogene c-Myc and cell proliferation rates in specific cancer cell lines. Methods The mRNA levels of c-Myc were evaluated using fluorescence-based qRT-PCR to examine the effect of AICAR treatment on c-Myc mRNA expression levels. Western blot was used to evaluate the protein levels of c-Myc following AICAR treatment. RNA interference was employed to determine whether the regulatory effect of AICAR on c-Myc was dependent on AMPK and the downstream metabolic enzymes relating to AICAR. Actinomycin D and cycloheximide were used to assess the effect of AICAR on the stability of cMyc mR-NA and protein. Western blot was used to examine the regulatory effect of AICAR on c-Myc in various cancer cell lines. The MTT assay was used to determine the effect of AICAR on cell viability in these cell lines. Results AICAR significantly up-regulated c-Myc at both mRNA and protein levels. The protein level of c-Myc reached a plateau 12 h after the AICAR treatment. The up-regulatory effect of c-Myc induced by AICAR was not dependent on either the AMPK signaling pathway or the downstream metabolites of AICAR. AICAR could significantly enhance the mRNA stability of c-Myc but did not affect the protein stability. The up-regulation of c-Myc induced by AICAR was cell-type specific. AICAR up-regulated c-Myc in SW1990, 786-0, and A549, while down-regulated c-Myc in HepG2, MCF7, and U20S. In HepG2 cells, AICAR treatment decreased cell viability. However, in SW1990 and A549 cells, AICAR treatment did not lead to any significant difference in cell viability. AICAR decreased the cell viability only when c-Myc was knocked down in SW1990 and A549 cells. Conclusions AICAR directly up-regulates c-Myc expression in an AMPK-independent manner. The up-regulation effect is cell-type dependent. The regulation of c-Myc expression by AICAR is linked to the inhibitory effect of AICAR on tumor cell proliferation.

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