Accumulation Of Adriamycin Research Articles

Discovery of (quinazolin-6-yl)benzamide derivatives containing a 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline moiety as potent reversal agents against P-glycoprotein-mediated multidrug resistance

P-glycoprotein (P-gp) is an important factor leading to multidrug resistance (MDR) in cancer treatment. The co-administration of anticancer drugs and P-gp inhibitors has been a treatment strategy to overcome MDR. In recent years, tyrosine kinase inhibitor Lapatinib has been reported to reverse MDR through directly interacting with ABC transporters. In this work, a series of P-gp inhibitors (1–26) was designed and synthesized by integrating the quinazoline core of Lapatinib into the molecule framework of the third-generation P-gp inhibitor Tariquidar. Among them, compound 14 exhibited better MDR reversal activity than Tariquidar. The docking results showed compound 14 displayed the L-shaped molecular conformation. Importantly, compound 14 increased the accumulation of Adriamycin (ADM) and rhodamine 123 (Rh123) in MCF7/ADM cells. Besides, compound 14 significantly increased ADM-induced apoptosis and inhibited the proliferation, migration and invasion of MCF7/ADM cells. It was also demonstrated that compound 14 significantly inhibited the growth of MCF7/ADM xenograft tumors by increasing the sensitivity of ADM. In summary, compound 14 has the potential to overcome MDR caused by P-gp.

NOD2 silencing promotes cell apoptosis and inhibits drug resistance in chronic lymphocytic leukemia by inhibiting the NF-κB signaling pathway.

Recent years have witnessed increasing studies on the effect of epigenetic silencing of genes in the progression of chronic lymphocytic leukemia (CLL). This study investigates whether the nucleotide binding oligomerization domain containing 2 (NOD2) participates in the cell apoptosis and drug resistance of CLL cells. Cells were treated with adriamycin (ADR), etoposide, aclacinomycin and daunorubicin. After treatment, drug resistance and cell proliferation were examined to detect the inhibitory effect of ADR on cell proliferation; flow cytometry to identify ADR accumulation, the cell cycle distribution and apoptosis after transfection, and rhodamine 123 accumulation and efflux tests to assess P-glycoprotein (P-gp) function. NOD2 silencing or inhibition of the nuclear factor kappa-B (NF-κB) signaling pathway suppressed the multidrug resistance level in CLL, the inhibition rate, and cell proliferation caused by ADR at concentrations of approximately 0.25-1.5 μmol/L. Greater accumulation of ADR was observed in the CLL-AAT cell line than in the CLL-AAT/A02 cell line, but NOD2 silencing or inhibition of the NF-κB signaling pathway further increased the accumulation of ADR drugs in the CLL-AAT cell line and inhibited the drug efflux pump function of P-gp. Additionally, NOD2 silencing or NF-κB signaling pathway inhibition increased the apoptotic rate. The results of this study indicate that NOD2 promotes cell apoptosis and reduces the drug resistance of CLL by inhibiting the NF-κB signaling pathway.

Structure-Based Discovery of Pyrimidine Aminobenzene Derivatives as Potent Oral Reversal Agents against P-gp- and BCRP-Mediated Multidrug Resistance.

Overexpression of ATP binding cassette (ABC) transporters, including P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP), is an important factor leading to multidrug resistance (MDR) in cancer treatments. Three subclasses of dual inhibitors of P-gp and BCRP were designed based on the active moieties of BCRP inhibitors, tyrosine kinase inhibitors, and P-gp inhibitors, of which compound 21 possessed low cytotoxicity, high reversal potency, and good lipid distribution coefficient. 21 also increased the accumulation of Adriamycin (ADM) and Mitoxantrone (MX), blocked Rh123 efflux, and made no change in the protein expression of P-gp and BCRP. Importantly, coadministration of 21 can significantly improve the oral bioavailability of paclitaxel (PTX). It was also demonstrated that 21 significantly inhibited the growth of K562/A02 xenograft tumors by increasing the sensitivity of ADM in vivo. In summary, 21 has the potential to overcome MDR caused by P-gp and BCRP and to improve the oral bioavailability of PTX.

The effects and mechanisms of aloe‐emodin on reversing adriamycin‐induced resistance of MCF‐7/ADR cells

Multidrug resistance (MDR) is one of the major obstacles for clinical effective chemotherapy. In this study, the effects and possible mechanisms of aloe‐emodin (AE) were investigated on reversing the adriamycin (ADR)‐induced resistance of MCF‐7/ADR cells. AE could significantly reverse the ADR resistance in MCF‐7/ADR cells. The combination of AE (20 μM) and ADR had no effect on the P‐glycoprotein (P‐gp) level, but notably promoted the accumulation of ADR in drug‐resistant cells. The efflux function of P‐gp required ATP, but AE reduced the intracellular ATP level. AE played a reversal role might through inhibiting the efflux function of P‐gp. The research result of energy metabolism pathways indicated that combination of AE and ADR could inhibit glycolysis, tricarboxylic acid (TCA) cycle, glutamine metabolism, and related amino acid synthesis pathways. Moreover, we found AE not only reversed ADR‐induced resistant but also induced autophagy as a defense mechanism. In addition, the combination of AE and ADR arrested G2/M cell cycle and induced apoptosis through DNA damage, ROS generation, caspase‐3 activation. Our study indicated that AE could be a potential reversal agent to resensitize ADR resistant in tumor chemotherapy and inhibiting autophagy might be an effective strategy to further enhance the reversal activity of AE.

Inhibitory effect of PI3Kδ inhibitor idelalisib on proliferation of human myeloid leukemia cells and the reversal effect on drug resistance to adriamycin.

To investigate the effect of adriamycin (ADM), idelalisib or ADM and their combination on cell proliferation and intracellular concentration of ADM, and to explore the reversal effect of idelalisib on drug resistance to ADM. The K562 and K562/ADM cells were respectively treated with ADM and idelalisib at different concentrations. The 50% inhibitory concentration (IC50) and drug resistance index (RI) of ADM to the 2 kinds of cells were measured by methyl thiazolyl tetrazolium (MTT) assay. Non-cytotoxic dose (cell inhibition rate <5%) of idelalisib in the 2 kinds of cells was determined. Then the K562 and k562/ADM cells were divided into the following groups: a K562 cells + ADM group, a K562 cells + ADM + idelalisib group, a K562/ADM cells + ADM group, and a K562/ADM cells + ADM + idelalisib group. The survival rates, the intracellular ATP levels, and the relative concentration of intracellular ADM were detected by MTT method, ATP bioluminescence assay (ATP-BLA) and flow cytometry (FCM), respectively. The cell survival rates were significantly decreased in a dose-dependent manner when the cells were treated with different doses of ADM (0.001-10.000 mg/L ). The IC50 value of ADM in the K562 and K562/ADM cells were 0.2 mg/L and 1.0 mg/L, respectively. The RI value was 5. The cell survival rates were also significantly decreased in a dose-dependent manner when the cells were treated with different doses of idelalisib (1-50 μmol/L). The non-cytotoxic dose of idelalisib in the K562 and K562/ADM cells were 25 μmol/L and 15 μmol/L, respectively. The cell survival rates in the ADM+ idelalisib group was less than that in the ADM group (P<0.05)；while there was no statistical difference between the ADM+ idelalisib group and the ADM group in the K562 cells (P>0.05). The intracellular ATP level in the K562 cells was about (91.502±0.479) mmol/L, and that in the K562/ADM cells was about (24.311±0.349) mmol/L. The intracellular ATP level in the ADM+ idelalisib group in the K562/ADM cells was less than that in the ADM group (P<0.05); but there was no statistical difference between the ADM + idelalisib group and the ADM group in the K562 cells (P>0.05). The absorption of intracellular ADM in the ADM + idelalisib group in the K562/ADM cells was more than that in the ADM group (P<0.05); but there was no statistical difference in the K562 cells between the 2 groups (P>0.05). The exclusion of intracellular ADM in the ADM + idelalisib group in the K562/ADM cells was less than that in the ADM group (P<0.05 or P<0.01)；but there was no statistical difference in the K562 cells between the 2 groups (P>0.05). Idelalisib exerts effect on inhibition of the proliferation in myeloid leukemia K562 and K562/ADM cells, which may partially reverse the drug resistance of K562/ADM cells to ADM. The mechanisms for the effect of idelalisib may be related to increasing the accumulation of ADM and inducing the cell apoptosis in the K562 and K562/ADM cells.

Puerarin sensitized K562/ADR cells by inhibiting NF-κB pathway and inducing autophagy.

Puerarin is an isoflavone isolated from Pueraria lobata (Willd.) Ohwi. In the present study, reversal effect and underlying mechanisms of puerarin on multidrug resistance (MDR) were investigated in K562/ADR cells. K562/ADR cells exhibited adriamycin (ADR) resistance and higher levels of MDR1 expression compared with K562 cells. Puerarin enhanced the chemosensitivity of K562/ADR cells and increased the ADR accumulation in K562/ADR cells. The expression levels of MDR1 were down-regulated by puerarin in K562/ADR cells. Luciferase reporter assay further demonstrated the inhibitory effect of puerarin on TNF-α-induced NF-κB activation. The phosphorylation of IκB-α was significantly suppressed by puerarin. In silico docking analyses suggested that puerarin well matched with the active sites of IκB-α. Moreover, a large number of autophagosomes were found in the cytoplasm of K562/ADR cells after puerarin treatment. The significant increase in LC3-II and beclin-1 was also observed, indicating autophagy induction by puerarin in K562/ADR cells. Puerarin induced cell cycle arrest and apoptosis in K562/ADR cells. Finally, puerarin inhibited phosphorylation of Akt and JNK. In conclusion, puerarin-sensitized K562/ADR cells by downregulating MDR1 expression via inhibition of NF-κB pathway and autophagy induction via Akt inhibition.

Silencing of the ARK5 gene reverses the drug resistance of multidrug-resistant SGC7901/DDP gastric cancer cells.

For several years, the multidrug resistance (MDR) of gastric cancer cells has been a thorny issue worldwide regarding the chemotherapy process and needs to be solved. Here, we report that the ARK5 gene could promote the multidrug resistance of gastric cancer cells in vitro and in vivo. In this study, LV-ARK5-RNAi lentivirus was used to transfect the parental cell line SGC7901 and MDR cell line SGC7901/DDP to construct a stable model of ARK5 interference. Subsequently, the cells were treated with four chemotherapeutic drugs, cisplatin (DDP), adriamycin (ADR), 5-fluorouracil (5-FU) and docetaxel (DR) and were subjected to the CCK8, colony formation, adriamycin accumulation and retention, cell apoptosis and other assays. The study found that, in vitro, the expression of ARK5 in MDR gastric cancer cells was significantly higher than that in parental cells. Additionally, when treated with different chemotherapeutic drugs, compared with parental cells, MDR cells also had a higher cell survival rate, higher colony formation number, higher drug pump rate, and lower cell apoptosis rate. Additionally, in xenograft mouse models, MDR cells with high ARK5 expression showed higher resistance to chemotherapeutic drugs than parental cells. Overall, this study revealed that silencing the ARK5 gene can effectively reverse the drug resistance of MDR gastric cancer cells to chemotherapeutic drugs, providing insights into the mechanism of this process related to its inhibition of the active pump-out ability of MDR cells.

Shenmai injection suppresses multidrug resistance in MCF-7/ADR cells through the MAPK/NF-κB signalling pathway

Context Shenmai Injection (SMI) is usually used to treat atherosclerotic coronary heart disease and viral myocarditis in China. However, the effect of SMI on multidrug resistance has not been reported. Objective To investigate the reversal effect of SMI in adriamycin (ADR) resistant breast cancer cell line (MCF-7/ADR) and explore the related molecular mechanisms. Materials and methods The effect of SMI (0.25, 0.5, 1 mg/mL) to reverse chemoresistance in MCF-7/ADR cells was elucidated by MTT, HPLC-FLD, DAPI staining, flow cytometric analysis, western blotting. At the same time, in vivo test was conducted to probe into the effect of SMI on reversing ADR resistance, and verapamil (10 μM) was used as a positive control. Results The results showed that the toxicity of ADR to MCF-7/ADR cells was strengthened significantly after treated with SMI (0.25, 0.5, 1 mg/mL), the IC50 of ADR was decreased 54.4-fold. The intracellular concentrations of ADR were increased 2.2-fold (p < 0.05) and ADR accumulation was enhanced in the nuclei (p < 0.05). SMI could strongly enhance the ADR-induced apoptosis and increase intracellular rhodamine 123 accumulation in MCF-7/ADR cells. Additionally, a combination of ADR and SMI (5 mg/kg) could dramatically reduce the weight and volume of tumour (p < 0.05). Furthermore, the results revealed that SMI might reverse MDR via inhibiting ADR-induced activation of the mitogen-activated protein kinase/nuclear factor (NF)-κB pathway to down-regulated the expression of P-glycoprotein (P-gp). Discussion and conclusions SMI could potentially be used to treat ADR-resistance. This suggests possibilities for future clinical research.

Catalpol alleviates adriamycin-induced nephropathy by activating the SIRT1 signalling pathway in vivo and in vitro.

Catalpol, a water-soluble active ingredient isolated from Rehmannia glutinosa, exhibits multiple pharmacological activities. However, the mechanism(s) underlying protection against renal injury by catalpol remains unknown. Adriamycin-induced kidney injury models associated with podocyte damage were employed to investigate the nephroprotective effects of catalpol. In vivo, TUNEL and haematoxylin-eosin staining was used to evaluate the effect of catalpol on kidney injury in mice. In vitro, effects of catalpol on podocyte damage induced by adriamycin was determined by elisa kit, flow cytometry, Hoechst 33342, and TUNEL staining. The mechanism was investigated by siRNA, EX527, and docking simulations. In vivo, catalpol treatment significantly improved adriamycin-induced kidney pathological changes and decreased the number of apoptotic cells. In vitro, catalpol markedly decreased the intracellular accumulation of adriamycin and reduced the calcium ion level in podocytes and then attenuated apoptosis. Importantly, the regulatory effects of catalpol on sirtuin 1 (SIRT1), multidrug resistance-associated protein 2 (MRP2), and the TRPC6 channel were mostly abolished after incubation with SIRT1 siRNA or the SIRT1-specific inhibitor EX527. Furthermore, docking simulations showed that catalpol efficiently oriented itself in the active site of SIRT1, indicating a higher total binding affinity score than that of other SIRT1 activators, such as resveratrol, SRT2104, and quercetin. Taken together, our results suggest that catalpol exhibits strong protective effects against adriamycin-induced nephropathy by inducing SIRT1-mediated inhibition of TRPC6 expression and enhancing MRP2 expression.

Lathyrane diterpenes from Euphorbia lathyris and the potential mechanism to reverse the multi-drug resistance in HepG2/ADR cells

P-glycoprotein (P-gp) plays a significant role in multi-drug resistance (MDR) of cancer cells, resulting in the failure of cancer chemotherapy. Lathyrane diterpene was a class of promising MDR modulator. The phytochemical investigation on the seeds of Euphorbia lathyris L. aff ;orded four new lathyrol-type diterpenoids (1-4), together with seventeen known ones (5-23). The structures of these compounds were elucidated by using 1D and 2D NMR spectroscopy. All the compounds were evaluated reversing MDR activity in HepG2/ADR cells. Compounds 2-4, 7-9, 11, 13-14, 16, 18-19, and 2 1-2 3 at 20 μM was able to reverse MDR of HepG2/ADR cells to adriamycin (reversal fold: 10.05–448.39). In the investigation of reversing the MDR mechanism, the most potent compound 21 facilitated the accumulation of intracellular adriamycin in HepG2/ADR cells in the time-dependent model. Although 21 neither affected the P-gp distribution nor expression in HepG2/ADR cells, the amount of P-gp monomer was induced by 21 and verapamil. Compound 21 has also activated the P-gp coupled ATPase activity in a dose-dependent model. The molecular docking analysis implied that 21 had lower binding energy than verapamil and adriamycin. The present data demonstrated that lathyrane diterpenes may act as a class of high-affinity P-gp substrate and was effluxed by P-gp monomer to reverse the MDR.

7-O-geranylquercetin contributes to reverse P-gp-mediated adriamycin resistance in breast cancer

AimsTo investigate the effect of 7-O-geranylquercetin (GQ), a derivative of quercetin (Q), on reversing drug resistance in breast cancer MCF-7/ADR cells and reveal the mechanisms related to P-glycoprotein (P-gp). Main methodsCell viability was determined by MTT assay. Accumulation of adriamycin (ADR) in cells was determined by confocal fluorescence microscope and microplate reader while that of rhodamine (Rh) was measured by flow cytometry. Expression levels of P-gp and MDR1 gene in cells were detected by western blot and Real-Time PCR, respectively. Molecular docking of GQ and Q with P-gp was conducted using AutoDock program. Xenograft model was established by inoculating MCF-7/ADR cells in BALB/c-nude mice. Tumor bearing mice were administered with ADR via tail vein injection and/or GQ (Q) by gavage. Expression levels of P-gp in tissues were detected by western blot and immunohistochemistry. Key findingsGQ could reverse drug resistance of MCF-7/ADR cells to ADR. GQ inhibited the efflux of ADR by down-regulating the expression of P-gp protein and its encoding gene MDR1 in MCF-7/ADR cells. Molecular modeling showed that GQ matched with P-gp better than Q. GQ enhanced the antitumor effects of ADR and decreased the expression of P-gp in mice and its activities were higher than that of Q. GQ could reverse drug resistance of MCF-7/ADR cells by down-regulating the expression of P-gp in vitro and in vivo. SignificancesThe reversal effect of GQ on P-gp-mediated drug resistance indicates its potential as a reversal agent for drug resistance in cancer chemotherapy.

Sodium azulene sulfonate reverses multidrug resistance in K562/A02 cells

Overexpression of p-glycoprotein (p-gp) is the main cause of multidrug resistance and chemotherapy failure in leukemia. Sodium azulene sulfonate (SAS) was used to reverse the multidrug resistance of human leukemia adriamycin-resistant strain K562/A02, and the underlying mechanism was investigated. Human leukemia cell line K562 and drug-resistant cell line K562/A02 in logarithmic phase were used in this study. After 48 hours of treatment of K562/A02 cells with SAS, the intrinsic cytotoxicity of chlorogenic acid and its sensitivity to adriamycin (ADM) were determined with MTT assay. The degree of reversal was calculated. Using ADM accumulation and rhodamine 123 efflux experiments, the average fluorescence intensity of ADM and rhodamine 123 (Rh123) in chlorogenic acid-treated K562/A02 cells was determined flow cytometrically. The expressions of p-gp, t-Akt and p-Akt in K562/A02 cells were assayed using Western blotting. SAS had almost no cytotoxic effect, and the degree of inhibition was only about 20% at the highest concentration of 100 mu-M. The EC50 of MDR reversal by SAS was in the nano range (539±37nM), and it had a high selectivity index for normal cells (&gt;185). The accumulation of ADM in drug-resistant cells was increased significantly after treatment with 1 and 5 mu-M SAS, while the efflux of Rh123 was significantly inhibited, suggesting that SAS reversed MDR by inhibiting p-gp function. Western blotting experiments showed that SAS downregulated the expression of p-gp by inhibiting PI3K/Akt signaling pathway. This contributed to the reversal of drug resistance.SAS effectively reverses multidrug resistance in vitro by inhibiting the function of p-gp in K562/A02 cells, through a mechanism involving downregulation of the P13K/Akt signaling pathway. Therefore, SAS may be a potential candidate drug for reversal of MDR.

Suppressing Hedgehog signaling reverses drug resistance of refractory acute myeloid leukemia.

BackgroundHedgehog (Hh) signaling is involved in the pathogenesis of tumors. By performing gene chip analysis, we predicted that Hh signaling might regulate multiple downstream pathways in acute myeloid leukemia (AML).MethodsIn this study, the potential role of the Hh pathway in refractory AML, and the impact of Hh expression on clinical prognosis were examined. We also investigated the role of the Hh inhibitor NVP-LDE225 in reversing drug resistance of refractory primary AML cells in vitro and the roles of multiple drug-resistant HL60/Adriamycin-resistant cells in vitro and in vivo (in a xenograft mouse model). Finally, we explored the underlying mechanisms.ResultsHh pathway was highly active in chemotherapy-resistant AML cells; by contrast, activation was less pronounced in chemosensitive cells and non-refractory primary cells. Strong activation of this pathway was associated with higher recurrence rates and poorer relapse-free and overall survival. NVP-LDE225 inhibited MRP1 protein expression, increased intracellular accumulation of Adriamycin, and reversed chemotherapeutic resistance. These effects were likely mediated through inhibition of the IGF-1R/Akt/MRP1 pathway. In the AML xenograft mouse model, NVP-LDE225 plus Adriamycin resulted in marked tumor regression.ConclusionThese findings suggest that targeting the Hh pathway might be a therapeutic avenue for overcoming MDR resistance and preventing refractory AML.

Usnea Acid as Multidrug Resistance (MDR) Reversing Agent against Human Chronic Myelogenous Leukemia K562/ADR Cells via an ROS Dependent Apoptosis.

Purpose Multidrug resistance (MDR) is a major obstacle in chemotherapy of leukemia treatments. In this paper, we investigated Usnea Acid (UA) as MDR reversal agent on hematologic K562/ADR cells via ROS dependent apoptosis. Methods CCK8 assay was used to measure cell viability rate of K562/ADR. Intracellular reactive oxygen species (ROS) generation, cell cycle distribution, cell apoptosis were measured with flow cytometry, respectively. Proteins related to apoptosis were measured by Western blot. Intracellular Adriamycin accumulation was observed by confocal microscopy and measured by flow cytometry. Results In vitro study showed intracellular Adriamycin accumulation was remarkably increased by UA. Cell viability treated with Adr (4 μM) was decreased from 89.8% ± 4.7 to 32% ± 8.9 by combined with UA (4 μM). Adr-induced apoptosis and G1/G0 phase cell cycle arrest were remarkably increased by UA, as well as, intracellular ROS level. However, MDR reversing activity of UA was inhibited by N-acetyl cysteine (NAC), a ROS scavenger. Conclusion These data provide compelling evidence that UA is a promising agent against MDR in leukemia cell line and suggest a promising therapeutic approach for leukemia.

Paris saponin VII reverses chemoresistance in breast MCF-7/ADR cells

Ethnopharmacological relevanceThe development of a multidrug-resistant (MDR) phenotype is a main obstacle to the successful treatment of breast cancer. Saponins of several herbs are considered as promising candidates for drug resistance treatment. We extracted Paris saponin VII (PS VII) from Trillium tschonoskii Maxim. and investigated whether it could sensitize chemoresistant breast cancer cells MCF-7/ADR to the cytotoxic effects of adriamycin. Materials and methodsMCF-7/ADR cells were exposed to 0.5 μM PSVII plus different concentrations of adriamycin (0–100 μM). Then, MTT assay and adriamycin accumulation assay were used to assess cell proliferation and intracellular adriamycin retention. P glycoprotein levels and intracellular rhodamine 123 (Rh-123) accumulations were investigated to measure the expression and activity of P-glycoprotein. A xenograft model of nude mouse was utilized to observe the effect of PSVII in vivo. ResultsTreatment with PSVII influenced cell viability of MCF-7/ADR cells, as well as sensitized MCF-7/ADR cells to the cytotoxic effects of adriamycin. Moreover, PSVII significantly downregulated MDR1 expression in MCF-7/ADR cells. Intravenous administration of PSVII significantly enhanced anticancer efficacy of adriamycin to MCF-7/ADR xenograft model in nude mice. ConclusionThese findings suggested a possible application of PSVII in combination with chemotherapy and/or as neo-adjuvant therapy in the treatment of MDR breast cancer.

Nobiletin Enhances Chemosensitivity to Adriamycin through Modulation of the Akt/GSK3β/β⁻Catenin/MYCN/MRP1 Signaling Pathway in A549 Human Non-Small-Cell Lung Cancer Cells.

Drug resistance is a major problem in the treatment of non-small-cell lung cancer (NSCLC). In this study, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was performed to identify the differentially expressed genes in Adriamycin (ADR)-resistant NSCLC A549/ADR cells compared with parental A549 cells. Among the tested phytochemicals, nobiletin (NBT) is able to overcome the ADR resistance of A549/ADR cells. NBT treatment decreased the expression of a neuroblastoma-derived MYC (MYCN) and multidrug resistance-associated protein 1 (MRP1) as well as downregulating Akt, GSK3β, and β-catenin. Consistent with these results, NBT treatment resulted in the accumulation of intracellular ADR. A combination index (CI) assay confirmed the synergistic effect of combined treatment with NBT and ADR in reducing the viability of A549/ADR cells (CI = 0.152). Combined treatment with NBT and ADR enhanced apoptosis in A549/ADR cells, as evidenced by increased caspase-3 activation, poly (ADP-ribose) polymerase (PARP) cleavage, and sub-G1 population compared to treatment with ADR alone. In vivo experiments using a mouse xenograft model revealed that combination therapy with NBT and ADR significantly reduced tumor volume by 84.15%. These data suggest that NBT can sensitize ADR-induced cytotoxicity against A549/ADR cells by inhibiting MRP1 expression, indicating that NBT could serve as an effective adjuvant agent for ADR-based chemotherapy in lung cancer.

The effects of ultrasound exposure on P-glycoprotein-mediated multidrug resistance in vitro and in vivo

BackgroundMultidrug resistance (MDR) is often responsible for the failure of chemotherapy treatment, and current strategies for cancer MDR are not adequately satisfying as to their efficacy and safety. In this study, we sought to determine the anti-MDR effects of ultrasound (US) irradiation and its underlying mechanisms against drug-resistance.MethodsMDR variant MCF-7/ADR cell lines and endothelial cell lines were used to determine the appropriate ultrasound intensity for in vitro experiments. MCF-7/ADR cell and HEPG2/ADM cells were used to assess the anti-MDR effect of US irradiation. Intracellular adriamycin (ADM) accumulation, Cell viability, cell proliferation and cell apoptosis were evaluated after ADM + US treatment or ADM treatment alone. MCF-7/ADR xenograft mice were used to investigate the appropriate ultrasound intensity for in vivo experiments and its effect on the long-term prognosis. Underlining mechanisms by which ultrasound exposure reversing MDR phenotype were investigated both in vitro and in vivo.ResultsCombination of ADM and 0.74 W/cm2 US irradiation enhanced ADM intracellular concentration and nuclear accumulation in MCF-7/ADR and HEPG2/ADM cells, compared to those treated with ADM alone. Enhanced cellular ADM uptake and nuclei localization was associated with increased cytotoxicity of ADM to ADM-resistant cells, lower ADM-resistant cell viability and proliferative cell ratio, and higher apoptotic cell ratio. More importantly, US exposure increased the effectiveness of ADM to inhibit tumor growth in MCF-7/ADR xenograft mice. Mechanistically, US exposure promoted ADM accumulation in MDR cells mainly through down-regulation of P-glycoprotein (P-gp), which is dependent on US-induced intracellular reactive oxygen species (ROS) production. US-induced oxidative stress promoted miR-200c-3p and miR-34a-3p expression by forming miR-200c/34a/ZEB1 double-negative feedback loop. Finally, US-induced miR-200c/34a overexpression decreased P-gp expression and reversed MDR phenotype.ConclusionUS irradiation could reverse MDR phenotype by activating ROS-ZEB1-miR200c/34a-P-gp signal pathway. Our findings offer a new and promising strategy for sensitizing cells to combat MDR and to improve the therapeutic index of chemotherapy.

Nitric oxide reverses drug resistance by inhibiting ATPase activity of p-glycoprotein in human multi-drug resistant cancer cells

BackgroundDevelopment of resistance to chemotherapy drugs is a significant problem in treating human malignancies in the clinic. Overexpression of drug efflux proteins, including P-170 glycoprotein (P-gp), an ATP-dependent efflux protein, is one of the main mechanisms responsible for multi-drug resistance (MDR). Because our previous studies have shown that nitric oxide (˙NO) or its related species inhibit the ATPase activities of topoisomerase II, we hypothesized that ˙NO should also inhibit the ATPase activity of P-gp and increase drug accumulation in MDR cells, causing a reversal of drug resistance. ResultsCytotoxicity and cellular accumulation studies showed that ˙NO significantly inhibited the ATPase activity of P-gp in isolated membranes and in NCI/ADR-RES tumor cells, causing an increase in drug accumulation and reversals of adriamycin and taxol resistance in the MDR cells. While ˙NO had no effects on topoisomerase II-induced, adriamycin-dependent DNA cleavage complex formation, it significantly inhibited adriamycin-induced DNA double-strand breaks. Electron spin resonance studies showed an increase in adriamycin-dependent hydroxyl radical formation in the presence of an NO-donor. ConclusionsThe reversal of drug resistance is due to inhibition of the ATPase activity by ˙NO, resulting in enhancement of the drug accumulation in the MDR cells. Furthermore, DNA damage was not responsible for this reversal of adriamycin resistance. However, formation of adriamycin-dependent toxic free radical species and subsequent cellular damage may be responsible for the increased cytotoxicity of adriamycin by ˙NO in NCI/ADR-RES cells. General significanceAppropriately designed NO donors would be ideal for the treatment of P-gp-overexpressing tumors in the clinic.

Combination of dihydromyricetin and ondansetron strengthens antiproliferative efficiency of adriamycin in K562/ADR through downregulation of SORCIN: A new strategy of inhibiting P-glycoprotein.

Though the advancement of chemotherapy drugs alleviates the progress of cancer, long-term therapy with anticancer agents gradually leads to acquired multidrug resistance (MDR), which limits the survival outcomes in patients. It was shown that dihydromyricetin (DMY) could partly reverse MDR by suppressing P-glycoprotein (P-gp) and soluble resistance-related calcium-binding protein (SORCIN) independently. To reverse MDR more effectively, a new strategy was raised, that is, circumventing MDR by the coadministration of DMY and ondansetron (OND), a common antiemetic drug, during cancer chemotherapy. Meanwhile, the interior relation between P-gp and SORCIN was also revealed. The combination of DMY and OND strongly enhanced antiproliferative efficiency of adriamycin (ADR) because of the increasing accumulation of ADR in K562/ADR-resistant cell line. DMY could downregulate the expression of SORCIN and P-gp via the ERK/Akt pathways, whereas OND could not. In addition, it was proved that SORCIN suppressed ERK and Akt to inhibit P-gp by the silence of SORCIN, however, not vice versa. Finally, the combination of DMY, OND, and ADR led to G2/M cell cycle arrest and apoptosis via resuming P53 function and restraining relevant proteins expression. These fundamental findings provided a promising approach for further treatment of MDR.

Pien Tze Huang () Overcomes Doxorubicin Resistance and Inhibits Epithelial-Mesenchymal Transition in MCF-7/ADR Cells.

To evaluate the effect of Pien Tze Huang (, PZH) on breast cancer chemoresistance and related epithelial-mesenchymal transition (EMT) and investigate the underlying mechanisms. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay was used to determine the cell viability. Adriamycin (ADR) staining observed by fluorescence microscope was performed to detect the accumulation of ADR. Transwell assay was used to analyze the cell migration and invasion. Western-blot was performed to detect the protein expression of related genes. MCF-7/ADR cells were resistant to ADR treatment, and PZH treatment inhibited the viability of MCF-7/ADR cells in a dose-dependent manner. PZH treatment also increased the intercellular accumulation of ADR and down-regulated the expression of ABCG2 and ABCB1 in MCF-7/ADR cells (P<0.05). In addition, PZH treatment inhibited EMT, migration and invasion of MCF-7/ADR cells (P<0.05). Moreover, PZH suppressed activation of transforming growth factor β1 (TGF-β) signaling in MCF-7/ADR cells (P<0.05). PZH treatment can effectively overcome chemoresistance via down regulating ABCG2, ABCB1 and inhibit EMT in ADR resistant human breast cancer cells via suppression of the TGF-β1 pathway.