MDR1 Gene Expression Research Articles

Mo1204 Inhibition of MDR1 Gene Expression and Enhancing Cellular Uptake for Effective Colon Cancer Treatment Using Dual-Surface-Functionalized Nanoparticles

G A A b st ra ct s knowledge this is among the first studies of esophageal microbiome in healthy, PPI-REE, and EoE children. Esophageal microbiome diversity and evenness was significantly different between healthy and EoE patients. PPI therapy modified the microbiome in richness and diversity towards that of healthy controls.. This suggests that changes in esophageal microbiome can be used to differentiate PPI-REE and EoE and could have implications on pathogenesis, evaluation and treatment of patients with EoE.

Effect of FosPeg® mediated photoactivation on P-gp/ABCB1 protein expression in human nasopharyngeal carcinoma cells

Multidrug resistance (MDR) refers to the ability of cancer cells to develop cross resistance to a range of anticancer drugs which are structurally and functionally unrelated. P-glycoprotein (P-gp) is the best studied MDR phenotype in photodynamic therapy (PDT) treated cells. Our pervious study demonstrated that FosPeg® mediated PDT is effective to NPC cell line models. In this in vitro study, the expression of MDR1 gene and its product P-gp in undifferentiated, poorly differentiated and well differentiated human nasopharyngeal carcinoma (NPC) cells were investigated. The influence of P-gp efflux activities on photosensitizer FosPeg® was also examined. Regardless of the differentiation status, PDT tested NPC cell lines all expressed P-gp protein. Results indicated that FosPeg® photoactivation could heighten the expression of MDR1 gene and P-gp transporter protein in a dose dependent manner. Up to 2-fold increase of P-gp protein expression were seen in NPC cells after FosPeg® mediated PDT. Interestingly, our finding demonstrated that FosPeg® mediated PDT efficiency is independent to the MDR1 gene and P-gp protein expression in NPC cells. FosPeg® itself is not the substrate of P-gp transporter protein and no efflux of FosPeg® were observed in NPC cells. Therefore, the PDT efficiency would not be affected even though FosPeg® mediated PDT could induce MDR1 gene and P-gp protein expression in NPC cells. FosPeg® mediated PDT could be a potential therapeutic approach for MDR cancer patients.

Responses of cytochrome P450, GST, and MXR in the mollusk Corbicula fluminea to the exposure to hospital wastewater effluents

Pharmaceutical products are a major group of chemical compounds that are continuously released into the environment. The primary pathway of pharmaceuticals to the aquatic environment is the discharge of wastewater effluents. The Psychiatric hospital of Montpon (Dordogne, France) operates with its wastewater treatment plant. We first evaluated the presence and concentrations of 27 pharmaceuticals compounds in these effluents. All of the 27 compounds were detected in these wastewater effluents at concentrations ranging between 37,500 ng L(-1) (paracetamol) and 150 ng L(-1) (citalopram). The aim of the study was then to evaluate the exposure effects of the effluents on cytochrome P450, GST, and MXR responses in Corbicula fluminea gills and digestive glands. Experiments on clams exposed during 1, 3, 7 14, and 21 days revealed a strong and continuous overexpression of mdr1 (multidrug resistant 1) gene expression in gills and transitory variations in pi-gst expression and GST activity. EROD activity increased also transitory after 1 day in the digestive gland of exposed clams. These results indicated that in the effluent, some molecules have undergone metabolism of phase 1 and/or phase 2.

A model of secreting murine mammary epithelial HC11 cells comprising endogenous Bcrp/Abcg2 expression and function.

Breast cancer resistance protein (Bcrp/Abcg2) and multidrug transporter 1 (Mdr1/Abcb1) are efflux proteins located in the apical membrane of mammary epithelial cells (MEC). Bcrp is induced in MEC during gestation and lactation, while Mdr1 is down-regulated during lactation. Numerous drugs and toxic compounds are known to be actively secreted into milk by Bcrp, but most chemicals have not been investigated in this respect, emphasizing the need for functional Bcrp studies in an established cell line with secreting mammary epithelial cells. The present study was undertaken to examine expressions of Bcrp and Mdr1 in mammary epithelial HC11 cells, derived from a mid-gestational murine mammary gland. In addition, Bcrp function was assessed by transport experiments with mitoxantrone (MX) in undifferentiated HC11 cells, in HC11 cells subjected to Bcrp RNA interference (RNAi), as well as in HC11 cells stimulated to differentiate by treatment with lactogenic hormones. Differentiated HC11 cells organized into alveolar-resembling structures and gene expression of the major milk protein β-casein was induced, whereas undifferentiated cells formed monolayers with lower β-casein expression. Bcrp and Mdr1 gene and protein were expressed in both undifferentiated and differentiated HC11 cells. Differentiation of HC11 cells resulted in increased Bcrp protein expression, while Mdr1 gene and protein expressions were reduced. The Bcrp inhibitor elacridar (GF120918) reduced secretion and increased accumulation of MX in both undifferentiated and differentiated HC11 cells. Silencing of the Bcrp gene caused an increased accumulation of MX. The results indicate that the HC11 cell model provides a promising tool to investigate transport of potential Bcrp substrates in mammary epithelial cells.

Effect of Siwu decoction on function and expression of P-glycoprotein in Caco-2 cells

To study the effect of Siwu decoction on the function and expression of P-glycoprotein (P-gp) in Caco-2 cells. The Real-time quantitative poly-merase chain reaction (Q-PCR) was used to analyze the mRNA expression of MDR1 gene in Caco-2 cells. Flow cytometer was used to study the effect of Siwu decoction on the uptake of Rhodamine 123 in Caco-2 cells, in order to evaluate the efflux function of P-gp. Western blotting method was used to detect the effect of Siwu decoction on the P-gp protein expression of Caco-2 cells. Compared with the blank control group, after Caco-2 incubation with Siwu decoction at concentrations of 3.3, 5.0, 10.0 g x L(-1) for 24, 48, 72 h, the mRNA expression of MDR1 was up-regulated, suggesting the effect of Siwu decoction in inducing the expression of MDR1. After the administration with Siwu decoction in Caco-2 cells for 48 h, the uptake of Rhodamine 123 in Caco-2 cells decreased by respectively 16.6%, 22.1% (P < 0.05) and 45.4% (P < 0.01), indicating that the long-term administration of Siwu decoction can enhance the P-gp efflux function of Caco-2 cells. After the incubation of Caco-2 cells with Siwu decoction for 48 h, the P-gp protein expression on Caco-2 cell emebranes, demonstrating the effect of Siwu decoction in inducing the protein expression of P-gp.

Reversal effect study of vitamin D on leukemia multidrug resistance cells

Objective To investigate the reversal effect of vitamin D on drug resistance leukemia cell lines Jurcat vitamin D/ADR, K562/ADR and its mechanism. Methods Non-toxic concentration of vitamin D was chosen by methyl thiazolyl tetrazolium, and on line concentration experiment; the contents of vitamin D for soft erythromycin in the cell and the cell surface of P-glycoprotein(P-gp) expression level were detected by using flow cytometry instrument and vitamin D for intracellular mdr1 mRNA and mrp1 mRNA expression was detected by Real-time polymerase chain reaction; vitamin D for the change of intra cellular glutathione glycosides peptide(GSH) content was detected by adoping biochemistry method. Results Resistance reversal in experiments showed that vitamin D could decrease soft erythromycin in the accumulation of drug resistant cells, with a dose-dependent relationship; vitamin D treatment Jurcat/ADR, K562/ADR cells after 48 h, chemotherapy drugs could increase the cell concentration, and reduce P-gp and the expression of mdr1 and mrp1 gene; vitamin D treatment Jurcat/ADR, K562/ADR after 48 h could decrease the intracellular GSH content in K562, K562/ADR, Jurcat and Jurcat/ADR. Conclusions Vitamin D has the drug resis-tance reversal agents to Jurcat/ADR, K562/ADR, which might be relevant to the inhibition of cell surface of P-gp proteins function and expression and reduction of the mdr1 and mrp1 expressions of resistance genes and reduction of intracellular GSH content.Vitamin D by influencing the above mechanism, which increases the drug concentration in cells, can effectively kill the tumor cells. Key words: Vitamin D; Leukemia multidrug resistance cells; Multidrug resistance; Reversal

Effect of quercetin on doxorubicin-induced expression of MDR1 gene in HL-60 cells

Leukemia cells can acquire a multidrug resistant (MDR) phenotype in response to a wide variety of chemotherapeutic agents including doxorubicin (Dox). In addition to the constitutive expression in the leukemia prior to chemotherapy, a complex phenotype of pleiotropic resistance is presented in the residual or recurrent leukemia. Recent studies showed Dox-induced coexpression of COX2 and MDR1 genes in human leukaemia cells, and whether Dox-induced MDR1 up-regulation in acute leukaemia cells is dependent on COX2-transcriptional activity and thus might be overcome or prevented with COX2-promotor inhibitor quercetin interfering with COX2 expression and activity. This study was purposed to investigate the impacts of quercetin on Dox-induced mRNA expression of MDR1 and COX2 genes in HL-60 leukemia cells. The MDR1 and COX2 mRNA expression in HL-60 cells was detected by RT-PCR; the prostaglandin E2 (PGE2) release was measured by ELISA; the cytotoxicity of Dox was determined by MTT test. The incubation of HL-60 cells with Dox not only up-regulated MDR1 mRNA, but also COX2 mRNA expression, and after co-incubation with quercetin or celecoxib, Dox-induced overexpression of MDR1 and COX2 mRNA were reduced by quercetin, not by celecoxib, whereas PGE2 release was significantly decreased with subsequent enhancement of Dox cytotoxic efficacy by both of them. Dox-induced MDR1 up-regulation may be dependent on COX2-transcriptional activity, not PGE2, suggesting that the existence of causal link between COX2 and MDR1 expression induced by Dox, and modulation of COX2 transcriptional expression by quercetin would not only sensitize leukemia cells to Dox, but also prevent the acquisition of MDR during chemotherapy.

Identification of trichlormethiazide as a Mdr1a/b gene expression enhancer via a dual secretion-based promoter assay.

Transporters of the ATP-binding cassette (ABC) family such as MDR1 play a pivotal role in persistence of brain homeostasis by contributing to the strict permeability properties of the blood–brain barrier. This barrier on one hand compromises treatment of central nervous system diseases by restricting access of drugs; on the other hand, an impaired or altered function of barrier building cells has been described in neurological disorders. The latter might contribute to increased vulnerability of the brain under pathological conditions or even enforce pathogenesis. Here, we present a novel approach for a systematic examination of drug impact on Mdr1 gene expression by establishing a dual reporter gene assay for the murine upstream core promoters of Mdr1a and b. We validated the time-resolved assay in comparison with single reporter gene constructs and applied it to analyze effects of a Food and Drug Administration (FDA)-approved drug library consisting of 627 substances. The chemo-preventive synthetic dithiolethione oltipraz was reidentified with our assay as an already known inducer of Mdr1 gene expression. Together with two newly characterized modifiers – gemcitabine and trichlormethiazide – we prove our findings in a blood–brain barrier culture model as well as in wild-type and Mdr1 knockout mice. In sum, we could demonstrate that our dual reporter gene assay delivers results, which also persist in the living animal and consequently is applicable for further analysis and prediction of Mdr1 regulation in vivo.

Selected mechanisms of molecular resistance of Candida albicans to azole drugs.

A phenomenon of increasing resistance of Candida spp. to azoles has been observed for several years now. One of the mechanisms of lack of sensitivity to azoles is associated with CDR1, CDR2, MRD1 genes (their products are active transport pumps conditioning drug efflux from pathogen's cell), and ERG11 gene (encoding lanosterol 14α-demethylase). Test material was 120 strains of Candida albicans (60 resistant and 60 susceptible to azole drugs) obtained from clinical samples. The first stage of experiment assessed the expression of CDR1, CDR2, MDR1 and ERG11 genes by Q-PCR. The impact of ERG11 gene's mutations on the expression of this gene was analysed. The final stage of the experiment assessed the level of genome methylation of Candida albicans strains. An increase in the expression of CDR2, MDR1 and ERG11 was observed in azole-resistant strains of Candida albicans in comparison to strains sensitive to this class of drugs. Furthermore, 19 changes in the sequence of ERG11 were detected in tested strains. Four of the discovered mutations: T495A, A530C, G622A and A945C led to the following amino acid substitutions: D116E, K128T, V159I and E266D, respectively. It has also been found that statistically five mutations: T462C, G1309A, C216T, C1257T and A945C affected the expression of ERG11. The applied method of assessing the level of methylation of Candida albicans genome did not confirm its role in the development of resistance to azoles. The results indicate however, that resistance of Candida albicans strains to azole drugs is multifactorial.

Effect of DMSA Modified Fe3O4 and Multidrug Resistance Modulator HZ08 on the Reversal of Multidrug Resistance in K562/A02 Cell Line

The objective of the present study was to investigate the reversible effect of HZ08 and daunorubicin(DNR) combined with dimercaptosuccinic acid modified iron oxide (DMSA-Fe3O4) magnetic nanoparticles (MNPs) in human chronic leukemia cell line K562/A02, and the mechanism potentially involved. The growth inhibition rate of K562/A02 cells was determined by Cell Counting Kit-8 (CCK-8) assay. Cell apoptosis and intracellular concentration of DNR were detected by flow cytometry (FCM). DAPI staining was used to view apoptotic cellular morphology. Subsequently, transcription levels of MDR1 mRNA and expression levels of P-glycoprotein (P-gp) and caspase-3 were determined by real time polymerase chain reaction (real-time PCR) and Western blotting analysis, respectively. group clearly exhibited more morphological changes (severe structural alterations) than other groups. In addition, transcription of MDR1 gene and protein expression of P-gp and caspase-3 of K562/A02 cells were regulated at the most remarkable extent in DNR-HZ08-MNPs group when compared with other groups. These findings suggest that the remarkable effects of the novel DNR-HZ08-MNPs on multidrug resistant K562/A02 leukemia cells would be a promising strategy for overcoming multidrug resistance. DisclosuresNo relevant conflicts of interest to declare.

Prognostic Value of Multi-Drug Resistance 1 Gene (MDR1) Expression in Newly Diagnosed Patients with Chronic Myeloid Leukemia on Nilotinib Treatment—a Subanalysis of the ENEST1st Study

Introduction MDR1 gene expression has recently been reported to be associated with clinical outcome in imatinib-resistant patients with chronic myeloid leukemia (CML) on second-line nilotinib treatment (Agrawal et al., Leukemia 2014). High MDR1 expression was predictive for achieving deeper cytogenetic and molecular responses as well as duration of chronic phase. We thus prospectively evaluated the value of MDR1 expression analysis in the first-line situation within a large European, multicenter trial of CML patients under treatment with nilotinib.Methods 305 patients enrolled on the ENEST1st study (Evaluating Nilotinib Efficacy and Safety in clinical Trials as First-Line Treatment, NCT01061177) consented to participate in this substudy. Of these, 225 patients were evaluable due to sample availability and presence of typical e14a2 and/or e13a2 BCR-ABL1 transcripts. The median age was 52 (range 18-83), 39% were female. Prior to therapy, the expression of MDR1, BCR-ABL1, and GUSB were determined using a serial dilution of a plasmid constructs harboring MDR1 and GUSB and BCR-ABL1 and GUSB sequences. Ratios MDR1/GUSB and BCR-ABL1/GUSB were calculated. ROC curves were established using initial MDR1 and BCR-ABL1 expression levels aiming to achieve the primary endpoint of MR4 (defined as BCR-ABL1 ≤ 0.01% on the International Scale [BCR-ABL1IS] or undetectable BCR-ABL1 in cDNA with ≥ 10,000 ABL1 transcripts) at 18 months or to achieve a MMR (≤ 0.1% BCR-ABL1IS) at 9 months. Mann-Whitney tests have been applied using a significance level of 0.05.Results At 9 months, 161 patients (72%) achieved MMR and at 18 months 111 patients (49%) a MR4. The median ratio MDR1/GUSB among all evaluable patients was 11.4% (range, 0.6-318.1), the median ratio BCR-ABL1/GUSB was 22.2% (range 0.09-198.7). Initial BCR-ABL1/GUSB levels did not predict MMR or MR4 at 9 or 18 months. However, initial ratios MDR1/GUSB were predictive for the achievement of MMR at 9 months (best cut-off 3.8%, sensitivity 88.8%, specificity 26.6%, AUC 0.598, p=0.022) and for reaching MR4 at 18 months (best cut-off 7.90%, sensitivity 72.1%, specificity 51.8%, AUC 0.624, p=0.001).Conclusions High MDR1 expression levels in newly diagnosed CML patients appear to be associated with deeper molecular responses within the first 18 months of nilotinib treatment. These data merit further exploration and if validated would justify the investigation of frontline CML therapy guided by baseline MDR1 expression levels. DisclosuresDietz:Novartis: Research Funding. Hanfstein:Bristol-Myers Squibb: Honoraria; Novartis: Research Funding. Rousselot:Novartis: Research Funding. Lange:Novartis: Consultancy, Honoraria, Research Funding. Maier:Novartis: Research Funding. Foroni:Novartis: Research Funding. Gerrard:Novartis: Research Funding. Talmaci:Novartis: Research Funding. Janssen:Novartis: Research Funding. Frank:Novartis: Employment. Saussele:Pfizer: Honoraria, Travel, Travel Other; Bristol-Myers Squibb: Honoraria, Research Funding, Travel, Travel Other; Novartis: Honoraria, Research Funding, Travel Other. Giles:Novartis: Honoraria, Research Funding. Hochhaus:Novartis: Research Funding. Müller:Novartis: Honoraria, Research Funding.

Effects of suberoylanilide hydroxamic acid (SAHA) combined with paclitaxel (PTX) on paclitaxel-resistant ovarian cancer cells and insights into the underlying mechanisms.

BackgroundSuberoylanilide hydroxamic acid (SAHA) is a member of the hydroxamic acid class of the newly developed histone deacetylase inhibitors. Recently, Suberoylanilide hydroxamic acid has attracted increasing attention because of its antitumor activity and synergistic effects in combination with a variety of traditional chemotherapeutic drugs. Paclitaxel (PTX), is a natural anticancer drugs; however, resistance to paclitaxel has become a major challenge to the efficacy of this agent. The purpose of this study was to investigate the effects of the combined application of these two drugs on the paclitaxel-resistant ovarian cancer OC3/P cell line.MethodsIn the present study, the effects of Suberoylanilide hydroxamic acid or/and paclitaxel on OC3/P cells cultured in vitro were analyzed in terms of cell viability, migration, cell-cycle progression and apoptosis by CCK-8, wound healing and flow cytometry assays. Changes in cell ultrastructure were observed by transmission electron microscopy. The expression of genes and proteins related to proliferation, apoptosis and drug resistance were analyzed by quantitative real-time polymerase chain reaction and Western blot analyses.ResultsThere was no cross-resistance of the paclitaxel-resistant ovarian cancer OC3/P cells to Suberoylanilide hydroxamic acid. Suberoylanilide hydroxamic acid combined with paclitaxel significantly inhibited cell growth and reduced the migration of OC3/P cells compared with the effects of Suberoylanilide hydroxamic acid or paclitaxel alone. Q-PCR showed the combination of Suberoylanilide hydroxamic acid and paclitaxel reduced intracellular bcl-2 and c-myc gene expression and increased bax gene expression more distinctly than the application of SAHA or paclitaxel alone. Moreover, the level of mdr1 gene expression in cells treated with Suberoylanilide hydroxamic acid was lower than that of the control group (P <0.05). Western blot analysis showed that Suberoylanilide hydroxamic acid alone or in combination with paclitaxel enhanced caspase-3 protein expression and degraded ID1 protein expression in OC3/P cells.ConclusionSuberoylanilide hydroxamic acid inhibited the growth of paclitaxel-resistant ovarian cancer OC3/P cells and reduced migration by the induction of cell-cycle arrest, apoptosis and autophagy. These observations indicate the possible synergistic antitumor effects of sequential Suberoylanilide hydroxamic acid and paclitaxel treatment.

Echinacea purpurea up-regulates CYP1A2, CYP3A4 and MDR1 gene expression by activation of pregnane X receptor pathway

1. This study investigated the mechanism underlying Echinacea-mediated induction of CYP1A2, CYP3A4 and MDR1 in terms of human pregnane X receptor (PXR) activation.2. Crude extracts and fractions of Echinacea purpurea were tested for PXR activation in HepG2 cells by a reporter gene assay. Quantitative real-time PCR was carried out to determine their effects on CYP1A2 and CYP3A4 mRNA expressions. Capsules and fractions were risk ranked as high, intermediate and remote risk of drug-metabolizing enzymes induction based on EC50 values determined for respective CYPs.3. Fractions F1, F2 and capsule (2660) strongly activated PXR with 5-, 4- and 3.5-fold increase in activity, respectively. Echinacea preparations potentiated up-regulation of CYP1A2, CYP3A4 and MDR1 via PXR activation.4. Thus E. purpurea preparations cause herb–drug interaction by up-regulating CYP1A2, CYP3A4 and P-gp via PXR activation.

Surface engineered nanostructured lipid carriers for targeting MDR tumor: Part I. Synthesis, characterization and in vitro investigation

Over expression of P-glycoprotein (P-gp) in cancer cells often results in highly aggressive, multi-drug resistant (MDR) phenotype. Such tumors are very difficult to treat with conventional therapy and often lead to failure of the treatment. In this work, we fabricated surface engineered hybrid lipid nanoparticles grafted with novel AL–HA polymer by mineralization technique. AL–HA graft polymer was prepared by covalent conjugation of alendronate sodium and hyaluronic acid. Compritol ATO 888 and capmule MCM C8 hybrid lipid mix was employed to prepare irinotecan containing nanostructured lipid carrier (NLC) by using functional excipients with P-gp inhibition activity. AL–HA was successfully grafted over NLC-Ir (uncoated irinotecan loaded NLC) by calcium-assisted mineralization. HA-NLC-Ir (hyaluronic acid coated irinotecan loaded NLC) particles have a nanoscale size of 386±2.2nm along with a zeta potential value of 19.7±1.2mV. NLC-Ir as well as HA-NLC-Ir showed a slow and sustained drug release. In vitro cell line studies performed on HT-29 and Colo-320 colon cancer cells revealed a reduced IC50 even in MDR cells. Flowcytometry studies demonstrated the capability of the developed nanocarriers to deliver the P-gp substrate moieties in MDR cancer cells. Furthermore, the targeting potential of HA-NLC was confirmed by CLSM studies. The cell line studies also revealed that NLC formulation had a potential of inhibiting P-gp by affecting ATPase activity and MDR1 gene expression.

The effect of two novel cholesterol-lowering agents, disodium ascorbyl phytostanol phosphate (DAPP) and nanostructured aluminosilicate (NSAS) on the expression and activity of P-glycoprotein within Caco-2 cells.

BackgroundMany drugs are substrates for P-glycoprotein (P-gp) and interactions involving P-gp may be relevant to clinical practice. Co-administration with P-gp inhibitors or inducers changes the absorption profile as well as the risk for drug toxicity, therefore it is important to evaluate possible P-gp alterations. The purpose of this study was to investigate the effect of two novel cholesterol-lowering agents, disodium ascorbyl phytostanol phosphate (DAPP) and nanostructured aluminium silicate (NSAS), a protonated montmorillonite clay, on mdr-1 gene expression and its protein, P-glycoprotein (P-gp) within Caco-2 cells.MethodsThe effects of DAPP and NSAS on the regulation of mdr-1 gene, P-gp protein expression and activity within Caco-2 cells, were determined using cell viability and cytotoxicity tests, RT-PCR, Western Blot analysis and bi-directional transport studies.ResultsWe observed a significant down-regulation of mdr-1 mRNA (e.g. 38.5 ± 17% decrease vs. control at 5 μM DAPP and 61.2 ± 25% versus control at 10 μM DAPP; n = 6, P* < 0.05) within Caco-2 cells. Western Blot analysis of P-gp expression showed that changes in mdr-1 gene expression lead to correlating changes in P-gp protein expression. This down-regulation of P-glycoprotein also resulted in decreased activity of P-glycoprotein compared to untreated control. In contrast, when Caco-2 cells were treated with NSAS, no changes in mdr-1 gene expression, P-gp protein expression nor P-gp activity were observed.ConclusionsDAPP but not NSAS decreases P-gp mediated drug efflux through decreased mdr-1 gene expression and consequently decreased P-gp protein expression. These findings have to be taken into consideration when DAPP is concurrently given with other drugs that are substrates for P-gp since drug-drug interactions harbour a safety issue and alter bioavailability profiles.NSAS does not have any P-gp altering properties and therefore might not affect drug-drug interactions. We conclude from this study that NSAS might make a safer drug candidate compared to DAPP for lowering LDL-cholesterol.

Abstract 4701: Acquisition of Oct-4 upregulation transactivates MDR1 and is associated with increased tumor recurrence in bladder cancer

Abstract Platinum-based drug like cisplatin is the standard first-line drug to treat patients with bladder cancer. However, tumors may recur and develop into multiple-drug resistant characteristics. The acquisition of resistance to conventional chemotherapy is a challenge in the treatment of bladder cancer relapse. Cancer stem cell (CSC) hypothesis has been an attractive theory. CSCs can resist therapeutic assaults, giving rise to multiple drug resistance and promotion of tumor relapse and metastasis. It has been shown that the fraction of cancer cells expressing MDR1 that functions as an energy-dependent drug efflux pump may be associated with Oct-4 expression. We have demonstrated that Oct-4 expression in bladder cancer predicts tumor progression. In the present study, we proposed that Oct-4 expression in bladder cancer increases MDR1 gene expression and thereby results in multiple drug resistance. We found a positive correlation between Oct-4 and MDR1 expression levels in clinical samples of bladder cancer. Furthermore, overexpression of Oct-4 increased MDR1 expression, which resulted in poor response to cisplatin in human bladder transitional cell carcinoma cells. Conversely, knockdown of Oct-4 reduced MDR1 expression and rendered cells hypersensitive to cisplatin. We also verified that Oct-4 transactivated the MDR1 gene promoter by binding to the Oct-4 response element (ORE). More importantly, Oct-4 and MDR1 gene expression could be induced by treatment with cisplatin, suggesting that Oct-4 is a member of the MDR1 enhanceosome. Our data can explain, in part, the high recurrence rate and drug resistance of bladder cancer. For clinical implication, we demonstrated that reduction of Oct-4 expression by all-trans retinoic acid, a derivative of vitamin A, improved sensitivity of bladder cancer cells to gemcitabine and cisplatin. In addition, we found that high expression levels of Oct-4 and MDR1 were associated with high tumor recurrence. Taken together, our results provide evidence that Oct-4 plays an important role in cisplatin-acquired resistance in bladder cancer. They also implicate Oct-4 as a therapeutic target. Note: This abstract was not presented at the meeting. Citation Format: Chia-Sing Lu, Ai-Li Shiau, Gia-Shing Shieh, Bing-Hua Su, Wu-Chou Su, Wen-Horng Yang, Chao-Liang Wu. Acquisition of Oct-4 upregulation transactivates MDR1 and is associated with increased tumor recurrence in bladder cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4701. doi:10.1158/1538-7445.AM2014-4701

MDR1 and cytochrome P450 gene-expression profiles as markers of chemosensitivity in human chronic myelogenous leukemia cells treated with cisplatin and Ru(III) metallocomplexes.

Leukemia is a major type of cancer affecting a significant segment of the population, and especially children. In fact, leukemia is the most frequent childhood cancer, with 26% of all cases, and 20% mortality. The multidrug resistance phenotype (MDR) is considered one of the major causes of failure in cancer chemotherapy. The present study aimed to investigate the relationship between the expression of MDR1 and CYP450 genes in human chronic myelogenous leukemia cells (K-562) treated with cisplatin (cisPt) and two ruthenium-based coordinated complexes [cisCRu(III) and cisDRu(III)]. The tested compounds induced apoptosis in K-562 tumor cells as evidenced by caspase 3 activation. Results also revealed that the amplification of P-gp gene is greater in K-562 cells exposed to cisPt and cisCRu(III) than cisDRu(III). Taken together, all these results strongly demonstrate that MDR-1 overexpression in K-562 cells could be associated to a MDR phenotype, and moreover, it is also contributing to the platinum and structurally related compound, resistance in these cells.

Vulvovaginal candidiasis: species distribution, fluconazole resistance and drug efflux pump gene overexpression.

The increasing incidence of vulvovaginal candidiasis (VVC) and the emergence of fluconazole resistance are an indisputable fact. However, little information is available regarding the correlation between fluconazole resistance in vaginal Candida albicans and the expression of drug efflux pump genes. In this study, we investigated the species distribution, fluconazole susceptibility profiles and the mechanisms of fluconazole resistance in Candida strains. In total, 785 clinical Candida isolates were collected from patients with VVC. C. albicans was the most frequently isolated species(n = 529) followed by C. glabrata (n = 164) and C. krusei (n = 57). Of all Candida isolates, 4.7% were resistant to fluconazole. We randomly selected 18 fluconazole resistant isolates of C. albicans to evaluate the expression of CDR1, CDR2, MDR1 and FLU1 genes. Compared with fluconazole-susceptible C. albicans isolates, CDR1 gene expression displayed 3.16-fold relative increase, which was statistically significant. CDR2, MDR1 and FLU1 overexpression was observed in several fluconazole-resistant C. albicans isolates, but statistical significance was not achieved. These results demonstrate a high frequency of non-albicans species (32.6%); however, C. albicans is the most common Candida species implicated in vaginitis, and this strain displays considerable fluconazole resistance. Meanwhile, our study further indicates that fluconazole resistance in C. albicans may correlate with CDR1 gene overexpression.

The clinical relevance and prognostic significance of adenosine triphosphate ATP-binding cassette (ABCB5) and multidrug resistance (MDR1) genes expression in acute leukemia: an Egyptian study.

Multidrug resistance (MDR1) represents a major obstacle in the chemotherapeutic treatment of acute leukemia (AL). Adenosine triphosphate ATP-binding cassette (ABCB5) and MDR1 genes are integral membrane proteins belonging to ATP-binding cassette transporters superfamily. The present work aimed to investigate the impact of ABCB5 and MDR1 genes expression on the response to chemotherapy in a cohort of Egyptian AL patients. The study included 90 patients: 53 AML cases and 37 ALL cases in addition to 20 healthy volunteers as controls. Quantitative assessment of MDR1 and ABCB5 genes expression was performed by quantitative real-time polymerase chain reaction. Additional prognostic molecular markers were determined as internal tandem duplications of the FLT3 gene (FLT3-ITD) and nucleophosmin gene mutation (NPM1) for AML cases, and mbcr-abl fusion transcript for B-ALL cases. In AML patients, ABCB5 and MDR1 expression levels did not differ significantly between de novo and relapsed cases and did not correlate with the overall survival or disease-free survival. AML patients were stratified according to the studied genetic markers, and complete remission rate was found to be more prominent in patients having low expression of MDR1 and ABCB5 genes together with mutated NPM1 gene. In ALL patients, ABCB5 gene expression level was significantly higher in relapsed cases and MDR1 gene expression was significantly higher in patients with resistant disease. In conclusion, the results obtained by the current study provide additional evidence of the role played by these genes as predictive factors for resistance of leukemic cells to chemotherapy and hence treatment outcome.

The ruthenium complexes cis-(dichloro)tetramineruthenium(III) chloride and cis-tetraammine(oxalato)ruthenium(III) dithionate overcome resistance inducing apoptosis on human lung carcinoma cells (A549).

Lung cancer is one of the leading causes of death in the world, and non-small cell lung carcinoma accounts for approximately 75-85 % of all lung cancers. In the present work, we studied the antitumor activity of the compound cis-(dichloro)tetramineruthenium(III) chloride {cis-[RuCl2(NH3)4]Cl} against human lung carcinoma tumor cell line A549. The present study aimed to investigate the relationship between the expression of MDR1 and CYP450 genes in human lung carcinoma cell lines A549 treated with cisCarboPt, cisCRu(III) and cisDRu(III). The ruthenium-based coordinated complexes presented low cytotoxic and antiproliferative activities, with high IC50 values, 196 (±15.49), 472 (±20.29) and 175 (±1.41) for cisCarboPt, cisCRu(III) and cisDRu(III), respectively. The tested compounds induced apoptosis in A549 tumor cells as evidenced by caspase 3 activation, but only at high concentrations. Results also revealed that the amplification of P-gp gene is greater in A549 cells exposed to cisCarboPt and cisCRu(III) than cisDRu(III). Taken together all these results strongly demonstrate that MDR-1 over-expression in A549 cells could be associated to a MDR phenotype of these cells and moreover, it is also contributing to the platinum, and structurally-related compound, resistance in these cells. The identification and characterization of novel mechanisms of drug resistance will enable the development of a new generation of anti-cancer drugs that increase cancer sensitivity and/or represent more effective chemotherapeutic agents.