Reversal of P-Glycoprotein-Dependent Resistance to Adriamycin by 5-bromotetrandrine in K562/A02 Cell Line.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4175-4175
Author(s):  
Bao-An Chen ◽  
Jue-Qiong Wang ◽  
Jia-Hua Ding ◽  
Feng Gao ◽  
Jian Chen ◽  
...  

Abstract Objective: The present study aimed to evaluate the MDR reversal activity of bromotetrandrine (BrTet), a bromized derivative of tetrandrine (Tet), in vitro. Methods: Drug sensitivity was determined using the MTT assay. Adriamycin (ADM) accumulation, the protein levels of P-glycoprotein (P-gp) and the apoptotic changes were analyzed by fluorospectrophotometry, respectively. The mRNA levels of P-gp was determined by RT-PCR. Results: BrTet at 0.25, 0.5 and reversed ADM resistance in MDR K562/A02 cells dose-dependently and its potency was greater than that of Tet at the same concentrations. The IC50 of ADM for K562 and K562/A02 cells were 55.122 mg/l and 1.1373 mg/l, respectively. Treating K562/A02 cells with BrTet(1uM)and TTD(1uM)both for 48 hours partially restored the sensitivity of K562/A02 cells to ADM (IC50 were 4.7729 mg/l and 13.584 mg/l respectively) but had not effect on K562 cells. The fold reversal (FR) were 11.55 and 4.06 respectively. K562/A02 cells showed apoptotic characteristics after treated with Brtet and Tet both for 48 hours compared with control group(apoptosis rate was 61.1%, 11.1% and 9.9%,respectively); Fluorospectrophotometric assay showed that BrTet significantly increased the intracellular accumulation of ADM in K562/A02 cells in a dose-dependent manner. The fluorescence intensity of intracellelar ADM in K562/A02 cells treated with ADM(1mg/L)was 33% of that in K562 cells. BrTet and Tet elevated the intracellular ADM concentration in K562/A02 cells up to 52% and 69%,respectively. BrTet also inhibited the overexpression of P-gp in K562/A02 cells. The fluorescence intensity of P-gp in K562 and K562/A02 cells was 0.5 and 97.97.The P-gp expression was down after treated with BrTet and TTD (65.05 and 54.86). The mdr1 mRNA was also down regulated. Conclusions: BrTet showed significant MDR reversal activity in vitro. Its activity may be related to the inhibition of P-gp overexpression and the increase in intracellular accumulation of anticancer drugs. BrTet may be a promising MDR modulator for eventual assessment in the clinic.

Pathobiology ◽  
2021 ◽  
pp. 1-12
Author(s):  
Ying Xie ◽  
Yuanyuan Ruan ◽  
Huimei Zou ◽  
Yixin Wang ◽  
Xin Wu ◽  
...  

<b><i>Objective:</i></b> The goal of the present study was to determine the expression of yes-associated protein 1 (YAP1) in renal tissues of mice with lupus nephritis (LN) and elucidate its role in the progression of renal fibrosis. <b><i>Methods:</i></b> C57BL/6 mice and MRL/lpr mice were selected for experimental comparison. Mouse kidney tissues were removed and sectioned for hematoxylin and eosin staining, Masson’s trichome staining, Sirius staining, and immunohistochemistry. The mRNA and protein levels of YAP1 in mouse kidney tissues were detected, and the correlation between YAP1 and fibronectin (FN) mRNA levels was analyzed. Mouse renal epithelial cells were used for in vitro experiments. After transfection and stimulation, the cells were divided into 4 groups, namely the C57BL/6 serum group (group 1), the MRL/lpr serum group (group 2), the MRL/lpr serum + siRNA-negative control group (group 3), and the MRL/lpr serum + siRNA-YAP1 group (group 4). Epithelial-mesenchymal transition (EMT) markers in each group were detected by Western blotting and immunofluorescence staining. Serum creatinine, blood urea nitrogen, and urinary protein levels were detected and assessed for their correlation with YAP1 mRNA levels by Spearman’s analysis. <b><i>Results:</i></b> Compared to C57BL/6 mice, MRL/lpr mice exhibited obvious changes in fibrosis in renal tissues. In addition, YAP1 expression was significantly higher in the renal tissues of MRL/lpr mice than in those of C57BL/6 mice, and YAP1 mRNA levels were positively correlated with those of FN. YAP1 silencing in lupus serum-stimulated cells could effectively relieve serum-induced EMT. Finally, we observed that YAP1 mRNA levels in mouse kidney tissue were significantly and positively correlated with the degree of renal function injury. <b><i>Conclusion:</i></b> YAP1 expression in the kidney tissues of LN mice was higher than that observed in normal mice, indicating that YAP1 may play an important role in the occurrence and development of LN.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5059-5059
Author(s):  
Bao-An Chen ◽  
Jue-qiong Wang ◽  
Jian Cheng ◽  
Feng Gao ◽  
Wen-lin Xu ◽  
...  

Abstract Objective This study was to compare the reversal effect of 5-bromotetrandrine (BrTet) with Tetrandrine (Tet) when combined with ADM on multidrug resistance cell line K562/A02 and to investigate the reversal mechanism of this new derivative. Methods The protein levels of P-glycoprotein (P-gp) were detected by fluorospectrophotometry and Western blot. The mRNA levels of P-gp were determined by RT-PCR. The in vivo effect of Tet was investigated using nude mice grafted with sensitive human leukemia cell line K562 and MDR cell line K562/A02. Results Flow cytometry assay showed that 1.0 μMol/L BrTet significantly increased the apoptosis percentage. BrTet also enhanced the intracellular accumulation of ADM in K562/A02 cells and its potency was greater than that of Tet at the same concentrations. BrTet inhibited the overexpression of P-gp and down regulated MDR1 mRNA expression in K562/A02 cells in a dose-dependent manner. In nude mice bearing K562 xenografts on the left flank and K562/A02 xenografts on the right flank, i.p. injection of 10 mg/kg BrTet significantly enhanced the antitumor activity of ADM against K562/A02 xenografts with inhibitory rates of 26.1%, while ADM alone inhibited the growth of KBv200 xenografts by only 5.8%. Conclusion BrTet showed significant MDR reversal activity in vitro and in vivo. Its activity may be related to the inhibition of P-gp overexpression and the increase in intracellular accumulation of anticancer drugs, which lead to more K562/A02 cells apoptosis.


2006 ◽  
Vol 290 (5) ◽  
pp. E916-E924 ◽  
Author(s):  
Juan Kong ◽  
Yan Chun Li

We have investigated the molecular mechanism whereby 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] inhibits adipogenesis in vitro. 1,25(OH)2D3 blocks 3T3-L1 cell differentiation into adipocytes in a dose-dependent manner; however, the inhibition is ineffective 24–48 h after the differentiation is initiated, suggesting that 1,25(OH)2D3 inhibits only the early events of the adipogenic program. Treatment of 3T3-L1 cells with 1,25(OH)2D3 does not block the mitotic clonal expansion or C/EBPβ induction; rather, 1,25(OH)2D3 blocks the expression of C/EBPα, peroxisome proliferator-activated receptor-γ (PPARγ), sterol regulatory element-binding protein-1, and other downstream adipocyte markers. The inhibition by 1,25(OH)2D3 is reversible, since removal of 1,25(OH)2D3 from the medium restores the adipogenic process with only a temporal delay. Interestingly, although the vitamin D receptor (VDR) protein is barely detectable in 3T3-L1 preadipocytes, its levels are dramatically increased during the early phase of adipogenesis, peaking at 4–8 h and subsiding afterward throughout the rest of the differentiation program; 1,25(OH)2D3 treatment appears to stabilize the VDR protein levels. Consistently, adenovirus-mediated overexpression of human (h) VDR in 3T3-L1 cells completely blocks the adipogenic program, confirming that VDR is inhibitory. Inhibition of adipocyte differentiation by 1,25(OH)2D3 is ameliorated by troglitazone, a specific PPARγ antagonist; conversely, hVDR partially suppresses the transacting activity of PPARγ but not of C/EBPβ or C/EBPα. Moreover, 1,25(OH)2D3 markedly suppresses C/EBPα and PPARγ mRNA levels in mouse epididymal fat tissue culture. Taken together, these data indicate that the blockade of 3T3-L1 cell differentiation by 1,25(OH)2D3 occurs at the postclonal expansion stages and involves direct suppression of C/EBPα and PPARγ upregulation, antagonization of PPARγ activity, and stabilization of the inhibitory VDR protein.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5063-5063
Author(s):  
Bao-An Chen ◽  
Qiu-xia Zhao ◽  
Jian Cheng ◽  
Feng Gao ◽  
Wen-lin Xu ◽  
...  

Abstract Objective: To study the reversal effect of Tetrandrine(Tet) and the estrogen-receptor inhibitor,toremifene(Tor),on multidrug resistance cell line K562/A02 and to investigate the reversal mechanism of this combination. Methods: ADM accumulation and the apoptosis percentage of K562 and K562/A02 cells were analyzed by fluorospectrophotometry, respectively. The protein levels of P-glycoprotein (P-gp) were detected by fluorospectrophotometry. The mRNA levels of mdr1 and Survivin were determined by RT-PCR. Results: The IC50 of ADM for K562/A02 and K562 cells were 57.43±4.55mg/L and 1.16±0.05mg/L respectively. Pretreating K562/A02 cells with toremifene(2.5μmol/L) or Tet(1μmol/L) for 72 hours partially restored the sensitivity of K562/A02 cells to ADM (IC50 were 20.74±1.62mg/L and 14.12±1.20mg/L respectively) but had no effect on K562 cells; IC50 of combined tetrandrine and toremifene was 9.14±1.03mg/L;K562/A02 showed apoptotic characteristics after treated with tetrandrine, toremifene (alone or combination);tetrandrine and toremifene (alone or combination) elevated the intracellular ADM accumulation in K562/A02; P-gp, mdr1 and Survivin mRNA were down regulated. Conclusion: Tetrandrine, toremifene (alone or combination) showed significant MDR reversal activity in vitro The reversal activity may be related to the inhibition of P-gp overexpression and down regulation the expression of mdr1 and Survivin mRNA to increase the intracellular accumulation of anticancer drugs, which lead to more K562/A02 cells apoptosis; Multidrug resistance (MDR) can be partially reversed by Tet or Tor of which the combination shows a great synergistic reversal effect.


2020 ◽  
Vol 295 (52) ◽  
pp. 18134-18147
Author(s):  
Xin Xu ◽  
Yihua Zhang ◽  
Junjie Zhang ◽  
Xiaotian Zhang

NSun2 is an RNA methyltransferase introducing 5-methylcytosine into tRNAs, mRNAs, and noncoding RNAs, thereby influencing the levels or function of these RNAs. Autotaxin (ATX) is a secreted glycoprotein and is recognized as a key factor in converting lysophosphatidylcholine into lysophosphatidic acid (LPA). The ATX-LPA axis exerts multiple biological effects in cell survival, migration, proliferation, and differentiation. Here, we show that NSun2 is involved in the regulation of cell migration through methylating ATX mRNA. In the human glioma cell line U87, knockdown of NSun2 decreased ATX protein levels, whereas overexpression of NSun2 elevated ATX protein levels. However, neither overexpression nor knockdown of NSun2 altered ATX mRNA levels. Further studies revealed that NSun2 methylated the 3′-UTR of ATX mRNA at cytosine 2756 in vitro and in vivo. Methylation by NSun2 enhanced ATX mRNA translation. In addition, NSun2-mediated 5-methylcytosine methylation promoted the export of ATX mRNA from nucleus to cytoplasm in an ALYREF-dependent manner. Knockdown of NSun2 suppressed the migration of U87 cells, which was rescued by the addition of LPA. In summary, we identify NSun2-mediated methylation of ATX mRNA as a novel mechanism in the regulation of ATX.


Author(s):  
Bin Wen ◽  
Yuan-ye Dang ◽  
Su-hua Wu ◽  
Yi-min Huang ◽  
Kong-yang Ma ◽  
...  

AbstractDespite improvements in cardiovascular disease (CVD) outcomes by cholesterol-lowering statin therapy, the high rate of CVD is still a great concern worldwide. Dehydrocorydaline (DHC) is an alkaloidal compound isolated from the traditional Chinese herb Corydalis yanhusuo. Emerging evidence shows that DHC has anti-inflammatory and antithrombotic benefits, but whether DHC exerts any antiatherosclerotic effects remains unclear. Our study revealed that intraperitoneal (i.p.) injection of DHC in apolipoprotein E-deficient (ApoE−/−) mice not only inhibited atherosclerosis development but also improved aortic compliance and increased plaque stability. In addition, DHC attenuated systemic and vascular inflammation in ApoE−/− mice. As macrophage inflammation plays an essential role in the pathogenesis of atherosclerosis, we next examined the direct effects of DHC on bone marrow-derived macrophages (BMDMs) in vitro. Our RNA-seq data revealed that DHC dramatically decreased the levels of proinflammatory gene clusters. We verified that DHC significantly downregulated proinflammatory interleukin (IL)-1β and IL-18 mRNA levels in a time- and concentration-dependent manner. Furthermore, DHC decreased lipopolysaccharide (LPS)-induced inflammation in BMDMs, as evidenced by the reduced protein levels of CD80, iNOS, NLRP3, IL-1β, and IL-18. Importantly, DHC attenuated LPS-induced activation of p65 and the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway. Thus, we conclude that DHC ameliorates atherosclerosis in ApoE−/− mice by inhibiting inflammation, likely by targeting macrophage p65- and ERK1/2-mediated pathways.


2021 ◽  
Vol 12 ◽  
Author(s):  
Ondrej Martinec ◽  
Carin Biel ◽  
Inge A. M. de Graaf ◽  
Martin Huliciak ◽  
Koert P. de Jong ◽  
...  

P-glycoprotein (ABCB1), an ATP-binding cassette efflux transporter, limits intestinal absorption of its substrates and is a common site of drug–drug interactions. Drug-mediated induction of intestinal ABCB1 is a clinically relevant phenomenon associated with significantly decreased drug bioavailability. Currently, there are no well-established human models for evaluating its induction, so drug regulatory authorities provide no recommendations for in vitro/ex vivo testing drugs’ ABCB1-inducing activity. Human precision-cut intestinal slices (hPCISs) contain cells in their natural environment and express physiological levels of nuclear factors required for ABCB1 induction. We found that hPCISs incubated in William’s Medium E for 48 h maintained intact morphology, ATP content, and ABCB1 efflux activity. Here, we asked whether rifampicin (a model ligand of pregnane X receptor, PXR), at 30 μM, induces functional expression of ABCB1 in hPCISs over 24- and 48-h incubation (the time to allow complete induction to occur). Rifampicin significantly increased gene expression, protein levels, and efflux activity of ABCB1. Moreover, we described dynamic changes in ABCB1 transcript levels in hPCISs over 48 h incubation. We also observed that peaks of induction are achieved among donors at different times, and the extent of ABCB1 gene induction is proportional to PXR mRNA levels in the intestine. In conclusion, we showed that hPCISs incubated in conditions comparable to those used for inhibition studies can be used to evaluate drugs’ ABCB1-inducing potency in the human intestine. Thus, hPCISs may be valuable experimental tools that can be prospectively used in complex experimental evaluation of drug–drug interactions.


2011 ◽  
Vol 435 (1) ◽  
pp. 259-266 ◽  
Author(s):  
Yi-Hsuan Wu ◽  
Avery G. Frey ◽  
David J. Eide

The Msc2 and Zrg17 proteins of Saccharomyces cerevisiae are members of the cation diffusion facilitator family of zinc transporters. These proteins form heteromeric complexes that transport zinc into the ER (endoplasmic reticulum). Previous studies suggested that the ZRG17 gene is regulated in response to zinc status by the Zap1 transcription factor. Zap1 activates the expression of many genes in zinc-deficient cells. In the present study, we assessed whether ZRG17 is a direct Zap1 target gene. We showed that ZRG17 mRNA levels were elevated in zinc-limited cells in a Zap1-dependent manner and were also elevated in zinc-replete cells expressing a constitutively active allele of Zap1. Furthermore, Zrg17 protein levels correlated closely with mRNA levels. A candidate Zap1-binding site [ZRE (zinc-responsive element)] in the ZRG17 promoter was required for this induction. Using electrophoretic mobility-shift assays and chromatin immunoprecipitation, we demonstrated that Zap1 binds specifically to the ZRG17 ZRE both in vitro and in vivo. By using a chromosomal ZRG17 mutant with a non-functional ZRE, we found that Zap1 induction of ZRG17 is required for ER function as indicated by elevated ER stress under zinc-limited conditions. Together, these results establish that ZRG17 is a direct Zap1 target gene and its regulation has biological importance in maintaining ER function.


2020 ◽  
Author(s):  
wangshu liu ◽  
Yang Yu ◽  
Juan Li ◽  
Hui Huang ◽  
Hao Liu ◽  
...  

Abstract Objective To observe the influence of the dual PI3K/mTOR inhibitor NVP-BEZ235 on proliferation and apoptosis of hemangioma cells in vitro and key molecules of the PI3K/Akt/mTOR signaling pathway.Methods Hemangioma-derived endothelial cells (HeECs) were obtained by surgical resection and cultured after the explants with the trypsin-digestion method. Fourth generation cells were cultured with serum-free medium for 24 hours. Then, the intervention group cells were added to the culture medium with 0.50 μM or 1.00 μM NVP-BEZ235. Cell proliferation was detected with CCK-8 assays, apoptosis was detected by flow cytometry, and PI3K, Akt, mTOR, and p70s6k protein levels were detected by Western blots. Then, the relationship between the phenotype of hemangioma vascular endothelial cells and the four proteins was analyzed.Results the 0.50 μM and 1.00 μM NVP-BEZ235 groups were significantly lower (0.88±0.03 and 0.59±0.05, respectively) than the control group (1.10±0.02) (P<0.01). The rate of G0/G1 phase cells in the 0.50 μM and 1.00 μM NVP-BEZ235 group were higher than the control group (P<0.01). The total rates of apoptotic cells in the 0.50 μM and 1.00 μM NVP-BEZ235 groups were higher than the control group (2.77±1.23)% (P<0.01). The PI3K pathway related protein levels in the NVP-BEZ235 group were lower than control group (P<0.01).Conclusion The PI3K/Akt/mTOR signaling pathway participates in hemangioma development. NVP-BEZ235 affected hemangioma vascular endothelial cells in vitro by regulating the PI3K/Akt/mTOR signaling pathway in a dose-dependent manner.


2017 ◽  
Vol 59 (3) ◽  
pp. 205-217 ◽  
Author(s):  
Yajie Guo ◽  
Junjie Yu ◽  
Chunxia Wang ◽  
Kai Li ◽  
Bin Liu ◽  
...  

MicroRNAs, a class of small noncoding RNAs, are implicated in controlling a variety of biological processes. We have shown that leucine deprivation suppresses lipogenesis by inhibiting fatty acid synthase (FAS) expression in the liver previously; the aim of our current study is to investigate which kind of microRNA is involved in the regulation of FAS expression in response to leucine deprivation. Here, we indicated that microRNA-212-5p specifically binds to mouse FAS 3′UTR and inhibits its activity. Leucine deficiency significantly increased the mRNA levels of miR-212-5p in the livers of mice. Further studies proved that miR-212-5p also directly binds to the 3′UTR of stearoyl-CoA desaturase-1 (SCD1) to inhibit its activity. Overexpression of miR-212-5p decreases the protein levels of FAS and SCD1 in vitro and in vivo, and silencing of miR-212-5p has the opposite effects in mouse primary hepatocytes. Moreover, overexpression of miR-212-5p significantly decreases triglyceride (TG) accumulation in primary hepatocytes and in the livers of mice injected with adenovirus-mediated overexpressing of miR-212-5p (Ad-miR-212). Interestingly, inhibition of miR-212-5p reverses the suppressive effects of leucine deficiency on FAS and SCD1 expression, as well as TG accumulation in mouse primary hepatocytes. Finally, we demonstrate that leucine deficiency induces the expression of miR-212-5p in a GCN2/ATF4-dependent manner. Taken together, our results demonstrate a novel function of hepatic miR-212-5p in the regulation of lipid metabolism which represents a potential therapeutic target for the treatment of non-alcohol fatty liver diseases (NAFLD).


Sign in / Sign up

Export Citation Format

Share Document