ABCB1 mRNA Expression Research Articles

Low Doses of Deoxynivalenol and Zearalenone Alone or in Combination with a Mycotoxin Binder Affect ABCB1 mRNA and ABCC2 mRNA Expression in the Intestines of Pigs.

Mycotoxin binders, in combination with enzymes degrading some mycotoxins, contribute to feed detoxification. Their use reduces economic losses and the negative impacts of mycotoxins on animal health and productivity in farm animals. The aim of this study was to evaluate the efficacy of a mycotoxin detoxifier on the expression of the ATP-binding cassette efflux transporters ABCB1 mRNA and ABCC2 mRNA, which transport xenobiotics and thus have a barrier function, in the tissues of pigs exposed to low doses of deoxynivalenol (DON, 1 mg/kg feed) and zearalenone (ZEN, 0.4 mg/kg feed) for 37 days. The levels of expression were determined by an RT-PCR, and the effect of the mycotoxin detoxifier (Mycofix Plus3.E) was evaluated by a comparison of results between healthy pigs (n = 6), animals treated with DON and ZEN (n = 6), and a group that received both mycotoxins and the detoxifier (n = 6). A significant downregulation of ABCB1 mRNA and ABCC2 mRNA was observed in the jejunum (p < 0.05). A tendencies toward the downregulation of ABCB1 mRNA and ABCC2 mRNA were found in the ileum and duodenum, respectively. The mycotoxin detoxifier restored the expression of ABCB1 mRNA to the level found in healthy animals but did not restore that of ABCC2 mRNA to the level of healthy animals in the jejunum.

Impact of ABCB1 and ABCG2 Transporter in Outcome of Gallbladder Cancer

BackgroundGallbladder cancer (GBC) is a biologically aggressive malignancy requiring appropriate biomarkers to improve its outcome. Role of ABC transporters (ABCB1 and ABCG2) has been linked to cancer aggressiveness, tumorigenesis and multidrug resistance. Herein, we studied the prognostic implication of ABCB1 and ABCG2 in GBC. MethodsFresh tissue (tumour & normal) samples collected from 54 patients who underwent R0 resection, were analysed for mRNA and protein expression of ABCB1 and ABCG2 by quantitative Real-Time PCR and western blotting respectively in this prospective study. The molecular findings were correlated with clinical-pathological parameters using χ2 and fisher exact test. The molecular changes in ABCB1 and ABCG2 was analysed for predicting overall survival (OS), disease free survival (DFS) and response to chemotherapy using Kaplan Meier log rank test and Cox regression multivariate analysis. ResultsThe mean age of the cohort was 50 ±13.2 with 26 (48.1%) patients had early stage gallbladder cancer (GBC). Overexpression of ABCB1 and ABCG2 was noted in 32/54(59%) and 40/54 (74%) cases respectively. The protein expression of ABCB1(P-glycoprotein) and ABCG2 (BCRP) was higher in 27/54 (50%) and 37/54 (59%) cases respectively. The mean OS and DFS was 20.7 ±11.5 and 19.3 ± 12.2 months at median follow up 24 months. The TNM stage, lymph node metastasis, and presence of gallstone were significant factors for predicting OS and DFS on multivariate analysis. Both ABCB1 and ABCG2 did not show any significant correlation with OS and DFS with similar incidence of late death and recurrence among over-expression and down-expression. Sub- group comparison suggests that change in expression pattern of ABCB1 and ABCG2 may not affect response to chemotherapy in GBC. ConclusionAltered expression of ABCB1 and ABCG2 may not be a useful prognostic marker for survival or response to chemotherapy in GBC. Presently, histo-pathological characteristics and associated gallstones are the important predictors for survival and recurrence in GBC.

SiRNA-Mediated Knockdown of ABCB1 Enhances the Efficacy of Doxorubicin and Vinorelbine in Breast Cancer Cells.

Breast cancer remains a leading cause of cancer-related deaths among women, primarily attributed to the formidable challenge of multidrug resistance, often driven by the overexpression of the ABCB1 gene. This study aimed to assess the synergistic effects of siRNA, doxorubicin, and vinorelbine on ABCB1 gene expression and cell viability in doxorubicin-resistant MCF-7/ADR breast cancer cells, with siRNA targeting ABCB1 to reduce its expression and doxorubicin/ vinorelbine to eradicate cancer cells. Our methodology involved culturing MCF-7 and MCF-7/ADR cells in standard cell culture conditions. The synthesized siRNA sequences transfected cells with siRNA at final concentrations of 10, 20, and 30 nM and assessed cell viability using the MTT assay was performed. Real-time PCR was employed to quantify ABCB1 mRNA expression levels. Results indicated that MCF-7/ADR cells exhibited substantial resistance to vinorelbine and doxorubicin compared to MCF-7 cells, displaying resistance at 12.50 μM and 25.00 μM for vinorelbine and 6.25 μM and 25.00 μM for doxorubicin. Remarkably, siRNA treatment effectively reversed drug resistance in MCF-7/ADR cells across all concentrations of vinorelbine and doxorubicin tested. When combined, siRNA, doxorubicin, and vinorelbine yielded a significantly greater reduction in cell viability compared to individual drug treatments, particularly at a 20 μM siRNA concentration. This combination therapy also significantly suppressed ABCB1 gene expression by a factor of 41.48 in MCF-7 cells relative to MCF-7/ADR cells. these findings suggest that combining siRNA, doxorubicin, and vinorelbine holds promise as a therapeutic strategy to overcome ABCB1-mediated multidrug resistance in breast cancer. Further investigations and clinical trials are warranted to evaluate its clinical efficacy rigorously.

Overcoming Breast Cancer Drug Resistance: A Novel Approach Using siRNA-Mediated P-glycoprotein Downregulation to Enhance Vinorelbine Efficacy.

Cancer, the second leading cause of mortality worldwide, represents a global health challenge, primarily due to drug resistance. Vinorelbine is a chemotherapeutic agent that disrupts cancer cell growth by targeting microtubules and inducing apoptosis. However, drug resistance remains a formidable obstacle. This resistance is caused by various factors including genetic mutations, drug efflux mechanisms, and DNA repair systems. Resolution of this challenge requires an innovative approach. This study investigated the potential of small interfering RNA (siRNA) to target and downregulate a vinorelbine-resistant MCF-7/ADR breast cancer cell line. Cells were cultured in Dulbecco's modified Eagle's medium (DMEM) 10% fetal bovine serum/penicillin/streptomycin. An siRNA targeting ABCB1 was designed and synthesized, and the cells were transfected with siRNA at final concentrations of 10, 20, and 30 nM. The3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to assess cell viability. ABCB1 mRNA expression levels were determined by real-time polymerase chain reaction (PCR). MCF-7 cells exhibited a higher sensitivity to vinorelbine than MCF-7/ADR cells. MCF-7/ADR cells exhibited resistance to vinorelbine at concentrations, 12.50 and 25.00 μM. Treatment with siRNA significantly reduced ABCB1 expression by 2.93-fold (P=0.0001). Similarly, co-treatment with siRNA and vinorelbine produced a substantial 2.89-fold decrease in ABCB1 gene expression in MCF-7 cells compared to that in MCF-7/ADR cells (P=0.0001). The results of the present study indicate that the concurrent use of siRNA and vinorelbine holds substantial promise as a therapeutic approach to overcome ABCB1-mediated multidrug resistance (MDR) in breast cancer. It is necessary to conduct comprehensive clinical trials to determine the true effectiveness of this combination therapy.

The potential therapeutic effect of melatonin in oxaliplatin combination therapy against chemoresistant colorectal cancer cells.

Oxaliplatin is one of the main therapeutics in colorectal cancer (CRC) chemotherapy. However, in light of multidrug resistance (MDR) phenotype development, the efficacy of oxaliplatin has decreased. This study aimed to assess the potential therapeutic effect of melatonin in oxaliplatin combination therapy for drug-resistant colorectal cancer cells. Initially, the oxaliplatin-resistant cell line was created of LS174T (LS174T/DR) by using the oxaliplatin IC50 concentration and resting cycles. MTT assays and flow cytometry were applied for assessing cell viability and apoptotic cells. The mRNA expression level of Bax, Bcl2, MT1, MT2, and ABCB1 as well as protein levels of ABCB1, Bcl2, BAX were measured by the qRT-PCR and western blot techniques respectively. P-gp activity was assessed by Rho123 staining. The IC50 concentration of oxaliplatin in resistant cells was increased from 500.7 ± 0.2 nM to 7119 ± 0.1 nM. Bcl2, MT1, MT2, and ABCB1 mRNA plus protein expression levels of Bcl2 and ABCB1 were significantly reduced in resistant cells, along with a marked increase in Bax mRNA and protein levels compared to parental cells. Rho 123 staining revealed a marked reduction in P-gp activities in the combination-treated group compared to the oxaliplatin-treated group. The results of cytotoxicity assays, MTT, and flow cytometry revealed that the combination of melatonin and oxaliplatin exerts synergistic effects on induction of oxaliplatin's cytotoxicity in CRC. Our research suggests that combining the treatments of melatonin and oxaliplatin may be considered as a new approach to overcoming oxaliplatin resistance in CRC patients.

ABCB1 Regulates Immune Genes in Breast Cancer.

Resistance to standard chemotherapy is a critical problem for breast cancer patients. The ATP-binding cassette (ABC) superfamily transporters actively pump out drugs and play an important role in chemoresistance. ABCB1 (ABC subfamily B, member 1, also named as multidrug resistance protein 1, MDR1) and suppressive myeloid-derived suppressor cells (MDSCs) potentially involve in chemoresistance of breast cancer. The relationship between ABCB1 and immune genes in breast cancer has not been widely studied. Microarray and RNA sequencing data were obtained from The Cancer Genome Atlas Breast Invasive Carcinoma in Genomic Data Commons Data Portal and Gene Expression Omnibus database. A patient-derived xenograft (PDX) model of HER2+ breast cancer was established to investigate the association between ABCB1 and immune genes in breast cancer. Expression of ABCB1 increased in doxorubicin-selected MCF-7/ADR cells. High expression of ABCB1 mRNA is correlated with lymph-node metastasis and worse overall survival in patients with breast cancer. ABCB1 is positively correlated with IL6, CSF1, CSF3, and PTGS2. In the HER2+ stage IIA breast cancer PDX model, both doxorubicin and paclitaxel suppressed growth of P2 tumors. IL6, CSF1, CSF3, and PTGS2 expression were suppressed by paclitaxel but not doxorubicin. Intrasplenic MDSCs, including CD11b+Ly6G+ and CD11b+Ly6C+ cells, were more abundant than intratumor MDSCs in PDX-carrying nude mice. Clinically, the patient developed cancer recurrence after adjuvant chemotherapy with doxorubicin-based regimen and was well controlled after paclitaxel-trastuzumab combined therapy. ABCB1 was a poor predictor of HER2+ LN- breast cancer. Regulation of immune genes by ABCB1 contributed to cancer recurrence and treatment effect. The PDX model was suitable for investigation the expression of target genes and expansion of immune cells.

The Role and Mechanism of MiR-451 in Multidrug Resistance of Leukemia Cell Line K562/A02

To detect the differential expressions of miR-451, ABCB1 and ABCC2 in drug-sensitive leukemia cell line K562 and drug-resistant cell line K562/A02, and explore the regulatory relationship between miR-451 and the expressions of ABCB1 and ABCC2 , and the mechanism of miR-451 involved in drug resistance in leukemia. CCK-8 assay was used to detect the drug resistance of K562/A02 and K562 cells. Quantitative Real-time PCR (qRT-PCR) was used to verify the differential expressions of miR-451 in K562 and K562/A02 cells. MiR-451 mimic and negative control (miR-NC), miR-451 inhibitor and negative control (miR-inNC) were transfected into K562 and K562/A02 cells respectively, then qRT-PCR and Western blot were used to detect the expression levels of mRNA and protein of ABCB1 and ABCC2 in K562 and K562/A02 cells and the transfected groups. The drug resistance of K562/A02 cells to adriamycin was 177 times higher than that of its parent cell line K562. Compared with K562 cells, the expression of miR-451 in K562/A02 cells was significantly higher (P <0.001), and the mRNA and protein expression levels of ABCB1 and ABCC2 in K562/A02 cells were significantly higher than those in K562 cells (P <0.001). After transfected with miR-451 inhibitor, the expression of miR-451 was significantly down-regulated in K562/A02 cells (P <0.001), the sensitivity to chemotherapy drugs was significantly enhanced (P <0.05), and the mRNA and protein expressions of ABCB1 and ABCC2 were significantly decreased (P <0.01). After transfected with miR-451 mimic, the expression of miR-451 was significantly upregulated in K562 cells (P <0.001), and the mRNA and protein expressions of ABCB1 and ABCC2 were significantly increased (P <0.01). There are significant differences in the expressions of miR-451, ABCB1 and ABCC2 between the drug-sensitive leukemia cell line K562 and drug-resistant cell line K562/A02, which suggests that miR-451 may affect the drug resistance of leukemia cells by regulating the expression of ABCB1 and ABCC2.

ABCB1 expression is increased in human first trimester placenta from pregnant women classified as overweight or obese

Obesity has become a global health challenge also affecting reproductive health. In pregnant women, obesity increases the risk of complications such as preterm birth, macrosomia, gestational diabetes, and preeclampsia. Moreover, obesity is associated with long-term adverse effects for the offspring, including increased risk of cardiovascular and metabolic diseases and neurodevelopmental difficulties. The underlying mechanisms are far from understood, but placental function is essential for pregnancy outcome. Transporter proteins P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP) are important for trans-placental transport of endogenous substances like lipids and cortisol, a key hormone in tissue maturation. They also hold a protective function protecting the fetus from xenobiotics (e.g. pharmaceuticals). Animal studies suggest that maternal nutritional status can affect expression of placental transporters, but little is known about the effect on the human placenta, especially in early pregnancy. Here, we investigated if overweight and obesity in pregnant women altered mRNA expression of ABCB1 encoding P-gp or ABCG2 encoding BCRP in first trimester human placenta. With informed consent, 75 first trimester placental samples were obtained from women voluntarily seeking surgical abortion (< gestational week 12) (approval no.: 20060063). Villous samples (average gestational age 9.35 weeks) were used for qPCR analysis. For a subset (n = 38), additional villi were snap-frozen for protein analysis. Maternal BMI was defined at the time of termination of pregnancy. Compared to women with BMI 18.5–24.9 kg/m2 (n = 34), ABCB1 mRNA expression was significantly increased in placenta samples from women classified as overweight (BMI 25–29.9 kg/m2, n = 18) (p = 0.040) and women classified as obese (BMI ≥ 30 kg/m2, n = 23) (p = 0.003). Albeit P-gp expression did not show statistically significant difference between groups, the effect of increasing BMI was the same in male and female pregnancies. To investigate if the P-gp increase was compensated, we determined the expression of ABCG2 which was unaffected by maternal obesity (p = 0.291). Maternal BMI affects ABCB1 but not ABCG2 mRNA expression in first trimester human placenta. Further studies of early placental function are needed to understand how the expression of placental transport proteins is regulated by maternal factors such as nutritional status and determine the potential consequences for placental–fetal interaction.

Molecular aspects of ABCB1 and ABCG2 in Gallbladder cancer and its clinical relevance.

The function of ABC transporters in the body is manifold; such as maintenance of homeostasis, effect on multi-drug resistance and their role in tumor initiation & progression. Evidence pointing towards the direct or indirect role of ABC transporter genes in particular; ABCB1 and ABCG2 in cancer genesis is increasing. However, their role in gallbladder cancer is unexplored. Therefore, we investigated the methylation status and expression pattern of ABCB1 and ABCG2in gallbladder carcinogenesis. The methylation and expression study of ABCB1/MDR1 and ABCG2/BCRP was performed in tumour and normal fresh tissue samples collected from 61 histopathologically diagnosed gallbladder cancer patients. The methylation status was analysed by Methylation-Specific PCR and expression was determined by Real-Time PCR and Immunohistochemistry. Hypomethylation of ABCB1 and ABCG2 was found in 44 (72.13%) and 48 (78.6%) cases, respectively. ABCB1 hypomethylation pattern showed association with female patients (p = 0.040) and GradeII tumors (p = 0.036) while, ABCG2hypomethylation was more frequent in early tumors (T1-T2). The mRNA expression ofABCB1 and ABCG2 was up-regulated in 33 (54.10%) and 41 (67.21%) patients with fold change of 4.7 and 5.5, respectively. The mRNA expression of both genes showed association with Grade II tumours and the increased fold change of ABCG2 was higher in (T1-T2) depth of invasion (p = 0.02) and Stage I-II disease (p = 0.08). The protein expression on IHC was strongly positive for ABCB1/MDR1and ABCG2/BCRP in 32 (52.46%) and 45 (73.77%) patients, respectively. The protein expression in ABCG2 showed association with patients age > 50years (p = 0.04) and GradeII differentiation (p = 0.07). Interestingly, the hypomethylation of both the genes showed significant correlation with increased expression. ABCB1/MDR1 and ABCG2/BCRP hypomethylation and overexpression could have a potential role in gallbladder cancer tumorigenesis especially in early stages. The epigenetic change might be a plausible factor for altered gene expression of ABCB1 and ABCG2 in gallbladder cancer.

Long noncoding RNA UCA1 promotes the expression and function of P-glycoprotein by sponging miR-16-5p in human placental BeWo cells.

Investigations on placental P-glycoprotein (P-gp) regulation could provide more therapeutic targets for individualized and safe pharmacotherapy during pregnancy. The role of long noncoding RNA (lncRNA) on placental P-gp regulation is lacking. The present study was carried out to investigate the regulation and underlying mechanisms of lncRNA urothelial carcinoma associated 1 (UCA1) on P-gp in Bewo cells. lncRNA UCA1 inhibition or overexpression could decrease or increase ABCB1 mRNA expression, P-gp expression and its cellular efflux function, respectively. RNA-FISH revealed that lncRNA UCA1 was mainly located in the cytoplasm of Bewo cells. MicroRNA array was applied and 10 significant miRNAs was identified after lncRNA UCA1 inhibition. Databases of LncTarD, LncRNA2Target, and miRcode were further used to search potential target miRNAs of lncRNA UCA1 and miR-16-5p was screened out. Thereafter, we confirmed that miR-16-5p expression was significantly upregulated or reduced after lncRNA UCA1 knockdown or overexpression, respectively. Furthermore, we also proved that ABCB1 mRNA expression, P-gp expression and its cellular efflux function was enhanced or reduced after miR-16-5p inhibition or overexpression, respectively. The rescue experiment further indicated that miR-16-5p was involved in the positive regulation of lncRNA UCA1 on the expression and function of P-gp. Lastly, dual-luciferase reporter system, RNA-binding protein immunoprecipitation and RNA pull-down assays were performed to explore the relationships among lncRNA UCA1, miR-16-5p, and ABCB1. It was found that lncRNA UCA1(1103-1125) could directly interact with miR-16-5p and miR-16-5p could directly target ABCB1 coding DNA sequence region (882-907). In conclusion, LncRNA UCA1 could promote the expression and function of P-gp by sponging miR-16-5p in BeWo cells.

Effects of ABCB1 DNA methylation in donors on tacrolimus blood concentrations in recipients following liver transplantation.

AimsTo investigate the effects of ABCB1 DNA methylation in donors on individual differences in tacrolimus blood concentrations following liver transplantation.MethodsTwenty‐three donor liver samples carrying the CYP3A5*3/*3 genotype were classified into 2 groups based on their initial tacrolimus blood concentrations (C0 >10 μg/L or <5 μg/L) following liver transplantation. ABCB1 mRNA levels in liver tissues and HepG2 cells were determined by quantitative reverse transcriptase polymerase chain reaction. DNA methylation status in liver tissues and HepG2 cells was determined using Illumina 850 methylation chip sequencing technology and pyrosequencing. 5‐Aza‐2dC was used to reverse methylation in HepG2 cells. Intracellular tacrolimus concentrations were determined by liquid mass spectrometry.ResultsGenome‐wide methylation sequencing and pyrosequencing analyses showed that the methylation levels of 3 ABCB1 CpG sites (cg12501229, cg00634941 and cg05496710) were significantly different between groups with different tacrolimus concentration/dose (C0/D) ratios. ABCB1 mRNA expression in donor livers was found to be positively correlated with tacrolimus C0/D ratio (R = .458, P < .05). After treatment with 5‐Aza‐2‐Dc, the methylation levels of the ABCB1 CpG sites in HepG2 cells significantly decreased, and this was confirmed by pyrosequencing; there was also a significant increase in ABCB1 transcription, which induced a decrease in intracellular tacrolimus concentrations.Conclusion ABCB1 CpG site methylation affects tacrolimus metabolism in humans by regulating ABCB1 expression. Therefore, ABCB1 DNA methylation in donor livers might be an important epigenetic factor that affects tacrolimus blood concentrations following liver transplantation.

Down-regulation of ABCB1 by collateral sensitivity drugs reverses multidrug resistance and up-regulates enolase I.

The emergence of drug resistance remains an obstacle in the clinical treatment of cancer. Recent developments in the studies of drug resistance have identified compounds such as verapamil and tamoxifen that specifically target ABCB1-expressing multidrug-resistant (MDR) cells, through an ATP-dependent ROS-generating mechanism. In this report, we demonstrate that treatment of ABCB1-expressing MDR cells (CHORC5 or MDA-Doxo400) or individual clones of the latter with sub-lethal concentrations of tamoxifen or verapamil down-regulates ABCB1 protein and mRNA expression in surviving clones. Consequently, tamoxifen- and verapamil-treated cells show increased sensitivity to chemotherapeutic drugs (e.g., colchicine and doxorubicin) and decreased sensitivity to collateral sensitivity drugs (e.g., verapamil and tamoxifen). Importantly, we show for the first time that down-regulation of ABCB1 expression resulting from tamoxifen treatment and CRISPR-knockout of ABCB1 expression up-regulate α-enolase (enolase I) protein levels and activity. These findings demonstrate a possible effect of ABCB1 expression on the metabolic homeostasis of MDR cells. Moreover, given the use of tamoxifen to prevent the recurrence of oestrogen receptor-positive breast cancer, the findings of this study may be clinically important in modulating activity of other drugs.

Polysaccharides Produced by the Mushroom Trametes robiniophila Murr Boosts the Sensitivity of Hepatoma Cells to Oxaliplatin via the miR-224-5p/ABCB1/P-gp Axis

Aim:To investigate the mechanisms employed by PS-T (polysaccharides of Trametes, PS-T), the main active ingredient of Huaier granules, to improve the susceptibility of hepatoma cells to oxaliplatin (OXA).Methods:Cell proliferation in response to PS-T was determined both in vitro and in vivo. The effects of PS-T on miRNAs were analyzed with the use of a microarray. MiRNAs were screened under specific conditions (P < .05, logFoldChange > ABS [1.5]) and further silenced or overexpressed by liposome transfection. Levels of ABCB1 mRNA and P-gp were detected by qRT-PCR and western blot analysis, respectively. A dual fluorescence assay was performed to determine whether miRNA directly targets ABCB1.Results:PS-T enhanced the inhibitory effect of OXA in human hepatoma cells and xenografts. Among 5 up-regulated miRNAs, overexpression of only miR-224-5p inhibited the expression of ABCB1 mRNA and P-gp, while silencing of miR-224-5p had an opposite effect. Moreover, miR-224-5p can directly target the 3′-UTR of ABCB1.Conclusion:PS-T increases the sensitivity of human hepatoma cells to OXA via the miR-224-5p/ABCB1/P-gp axis.

The gut microbiota contributes to the modulation of intestinal CYP3A1 and P-gp in streptozotocin-induced type 1 diabetic rats

Hepatic and intestinal CYP3A and P-gp in diabetic rats exhibit opposite expression patterns. However, the underlying mechanisms remain unclear. In this study, CYP3A1 and P-gp protein and mRNA expression levels in liver and different intestinal segments (duodenum, jejunum, ileum and colon) were compared between diabetic and normal rats. The microbiota in the ileum and colon contents was analyzed via 16S rRNA high-throughput sequencing technology. Caco-2 cells were incubated with serum or culture supernatant of colon contents from diabetic and normal rats, and CYP3A4 and ABCB1 mRNA levels were measured. Compared with that in normal rats, hepatic CYP3A1 and P-gp protein expression in diabetic rats was increased. CYP3A1 and P-gp protein was not changed in the duodenum and jejunum but significantly decreased by 29-41% in the ileum and colon of diabetic rats. Cyp3a1 and Abcb1a mRNA expression results were similar to the protein expression results. The composition of some bacteria changed significantly in the ileum and colon of diabetic rats compared with normal rats. CYP3A1 and P-gp protein expression was positively correlated with Lachnoclostridium and unclassified_f_Ruminococcaceae but negatively correlated with Clostridium_sensu_stricto_1, Turicibacter, Ruminococcaceae_UCG-005 and several genera belonging to the family Prevotellaceae. In addition, in vitro cell culture experiments showed that serum from diabetic rats significantly induced CYP3A4 and ABCB1 mRNA expression, while the supernatant of colon contents of diabetic rats significantly reduced CYP3A4 and ABCB1 mRNA expression by 45% and 86% respectively in Caco-2 cells. In conclusion, diabetes exhibited synchronous and regional effects on CYP3A and P-gp expression in the intestinal tract, in which gut microbiota dysbiosis might play an important role.

Modulatory influences of antiviral bioactive compounds on cell viability, mRNA and protein expression of cytochrome P450 3A4 and P-glycoprotein in HepG2 and HEK293 cells

The induction of cytochrome P450 3A4 (CYP3A4) and P-glycoprotein (ABCB1) influence drug plasma, and eventually decreases the drugs’ therapeutic effects. The effects of Plant-derived compounds (PCs) on drug-metabolising proteins are largely unknown. This study investigated the cytotoxicity, cell viability profiles and regulatory influences of four PCs (epigallocatechin gallate (EGCG), kaempferol-7-glucoside (K7G), luteolin (LUT) and ellagic acid (EGA)) on the mRNA and protein expressions of CYP3A4 and ABCB1 in HepG2 and HEK293 cells. After treatment with the PCs (0–400 µM) for 24 h, 80% (IC20) and 50% (IC50) cell viability were determined. The PCs were not toxic to HepG2 (ATP levels increased at IC20, insignificant change in LDH (lactate dehydrogenase) with the exception of LUT, and ABCB1 protein expressions decreased. The PCs decreased CYP3A4 at IC20 (except LUT), EGCG and K7G at IC20 decreased mRNA expression. For HEK293 cells, no significant change in ATP, except for EGCG IC20 and K7G IC50 which decreased and increased, respectively. LDH decreased at IC20, but LUT IC50 significant increase LDH. ABCB1 protein expression increased at both IC20 and IC50, but LUT and EGA at IC50 decreased mRNA expression. The PCs at IC20, and IC50 of LUT, K7G and of EGCG may enhance drug bioavailability.

Plasma imatinib levels and ABCB1 polymorphism influences early molecular response and failure-free survival in newly diagnosed chronic phase CML patients

Achieving early molecular response (EMR) has been shown to be associated with better event free survival in patients with chronic phase chronic myeloid leukemia (CP-CML) on Imatinib therapy. We prospectively evaluated the factors influencing the 2-year failure free survival (FFS) and EMR to imatinib therapy in these patients including day29 plasma Imatinib levels, genetic variants and the gene expression of target genes in imatinib transport and biotransformation. Patients with low and intermediate Sokal score had better 2-year FFS compared to those with high Sokal Score (p = 0.02). Patients carrying ABCB1-C1236T variants had high day29 plasma imatinib levels (P = 0.005), increased EMR at 3 months (P = 0.044) and a better 2 year FFS (P = 0.003) when compared to those with wild type genotype. This translates to patients with lower ABCB1 mRNA expression having a significantly higher intracellular imatinib levels (P = 0.029). Higher day29 plasma imatinib levels was found to be strongly associated with patients achieving EMR at 3 months (P = 0.022), MMR at 12 months (P = 0.041) which essentially resulted in better 2-year FFS (p = 0.05). Also, patients who achieved EMR at 3 months, 6 months and MMR at 12 months had better FFS when compared to those who did not. This study suggests the incorporation of these variables in to the imatinib dosing algorithm as predictive biomarkers of response to Imatinib therapy.

Effect of ABCB1 Multidrug Resistance Protein on Efficacy of Anti-Myeloma Drugs in Carfilzomib-Resistant Myeloma Model

Development of multidrug resistance is a major problem in treating cancer patients. Over-expression of a multidrug resistance protein MDR/P-gp/ABCB1 is recognized as a mediator of resistance to chemotherapy drugs in many cancers, including hematological malignancies. Recent studies have demonstrated that ABCB1 mediates resistance to a proteasome inhibitor carfilzomib. In this study we employ an isogenic ABCB1+ and ABCB1- pair of myeloma cell lines to investigate the effect of ABCB1 expression on a broader panel of anti-myeloma drugs. Expression of ABCB1 gene was assessed in publicly available gene expression datasets, including patient samples and murine models. ABCB1+ carfilzomib-resistant subline of myeloma cells AMO-1 was subject to CRISPR/Cas knock-out of ABCB1 gene. Two clones were isolated as a result of this procedure: one clone is ABCB1-negative and the other still bearing ABCB1. A panel of myeloma drugs consisting of carfilzomib, bortezomib, melflufen (melphalan flufenamide), melphalan, bendamustine, pomalidomide, iberdomide, panobinostat, doxorubicin, daunorubicin, vincristine, and paclitaxel was investigated in cytotoxicity assays using ABCB1+ and ABCB1- isogenic sublines of carfilzomib-adapted derivative of AMO-1. Myeloma multi-drug resistance (MMDR) score for each drug was calculated as a ratio between IC50 in ABCB1+ subline to IC50 in a ABCB1- subline. Apoptosis was measured by flow cytometry. According to the regression analysis of GSE136337, elevated expression of ABCB1 mRNA is associated with shorter PFS and OS in MM patients (Figure 1, A and B). Up-regulated murine Abcb1b expression was found in murine Vk*MYC myeloma tumors (GSE111921) prone to development of extramedullary disease (EMD) (Figure 1C). Cytotoxicity assays revealed a group of myeloma drugs vulnerable to elevated ABCB1 expression including carfilzomib, panobinostat, doxorubicin, daunorubicin, vincristine and paclitaxel (Figure 1D). No cytotoxicity against carfilzomib-resistant derivatives of AMO-1 myeloma cell line was observed for pomalidomide and iberdomide. Cytotoxicities of melflufen, bortezomib, melphalan, and bendamustine were only mildly affected by elevated ABCB1 expression (Figure 1D). In line with this observation, apoptosis upon carfilzomib treatment was reduced in ABCB1+ myeloma cells, whereas treatment with melflufen has resulted in equal cell death rates in both ABCB1- and ABCB1+ clones (Figure 1E). ABCB1 efflux pump is well recognized as a mediator of multi drug resistance in cancer. In this study we investigated the effect of ABCB1 on the efficacy of myeloma drugs in carfilzomib-resistant myeloma cells. In vitro efficacies of carfilzomib, panobinostat, doxorubicin, vincristine, and paclitaxel are negatively affected by ABCB1 over-expression (MMDR&amp;gt;4), whereas melflufen, bortezomib, melphalan, and bendamustine were not greatly affected (MMDR&amp;lt;2) (Figure 1F). However, melflufen has shown better cytotoxicity in carfilzomib-resistant myeloma, which is 20-fold greater compared to melphalan and 200-fold greater compared to bendamustine (Figure 1D). In addition, we found elevated ABCB1 expression in murine myeloma tumors prone to develop EMD. Moreover, elevated ABCB1 mRNA expression was associated with shorter PFS and OS in patients with multiple myeloma. Thus, this study may propose a novel therapy strategy including a novel lipophilic peptide-drug conjugate melflufen for myeloma patients with elevated ABCB1 which may potentially develop in carfilzomib-relapsed/refractory setting or EMD. Figure 1 Disclosures Byrgazov: Oncopeptides AB: Current Employment. Slipicevic:Oncopeptides AB: Current Employment. Lehmann:Oncopeptides AB: Current Employment, Current equity holder in publicly-traded company.

Curcumin ameliorates duodenal toxicity of AFB1 in chicken through inducing P-glycoprotein and downregulating cytochrome P450 enzymes

It has been reported that oral intake of aflatoxin B1 (AFB1)-contaminated feed could cause acute, sub-chronic, or chronic toxicity in livestock and poultry. However, the harmful effect of AFB1 on the small intestine is still controversial. Therefore, blocking the entry of AFB1 into the body through the digestive tract is one of the important methods to prevent its toxicity. In the present study, 1-day-old Arbor Acres broilers were randomly divided into 6 groups including control group, curcumin control group (450 mg curcumin/kg feed), curcumin low-, medium-, and high-dose group (150, 300, and 450 mg curcumin/kg feed + 5 mg AFB1/kg feed), and AFB1 group (5 mg AFB1/kg feed). After 28 d, the samples of chickens' duodenums were collected for further analyses. AFB1 caused abnormal functional and morphological changes in the duodenum, including histological lesions, increased the length of the duodenum and depth of crypt, decreased the unit weight of the duodenum, height of villus, and the value of villus height/crypt depth. Meanwhile, AFB1 administration enhanced malonaldehyde activity, 8-HOdG level, and the mRNA expression of cytochrome P450 (CYP450) enzymes, and reduced superoxide dismutase, catalase, adenosine triphosphatase (ATPase) activity and the mRNA expression of Abcb1. Importantly, curcumin supplementation partially ameliorated AFB1-induced abnormal functional and morphological signs of the duodenum, alleviated AFB1-induced oxidative stress, and decreased the mRNA expression of CYP450 enzymes. Furthermore, curcumin ameliorated AFB1-induced decrease in the Abcb1 mRNA expression, P-glycoprotein (P-gp) level, and ATPase activities. It has been suggested from these results that curcumin supplementation in the feed could ameliorate AFB1-induced duodenal toxicity and damage through downregulating CYP450 enzymes, promoting ATPase activities, and inducing P-gp in chickens.

Effect of ABC transporter expression and mutational status on survival rates of cancer patients

ATP-binding cassette (ABC) transporters mediate multidrug resistance in cancer. In contrast to DNA single nucleotide polymorphisms in normal tissues, the role of mutations in tumors is unknown. Furthermore, the significance of their expression for prediction of chemoresistance and survival prognosis is still under debate.We investigated 18 tumors by RNA-sequencing. The mutation rate varied from 27,507 to 300885. In ABCB1, three hotspots with novel mutations were in transmembrane domains 3, 8, and 9. We also mined the cBioPortal database with 11,814 patients from 23 different tumor entities. We performed Kaplan-Meier survival analyses to investigate the effect of ABC transporter expression on survival rates of cancer patients.Novel mutations were also found in ABCA2, ABCA3, ABCB2, ABCB5, ABCC1-6, and ABCG2. Mining the cBioPortal database with 11,814 patients from 23 different tumor entities validated our results. Missense and in-frame mutations led to altered binding of anticancer drugs in molecular docking approaches. The ABCB1 nonsense mutation Q856* led to a truncated P-glycoprotein, which may sensitize tumors to anticancer drugs. The search for ABC transporter nonsense mutations represents a novel approach for precision medicine..Low ABCB1 mRNA expression correlated with significantly longer survival in ovarian or kidney cancer and thymoma. In cancers of breast, kidney or lung, ABC transporter expression correlated with different tumor stages and human populations as further parameters to refine strategies for more individualized chemotherapy.

Effect of Foslip® mediated photodynamic therapy on 5-fluorouracil resistant human colorectal cancer cells.

Colorectal cancer (CRC) is the commonest cancer in Hong Kong and is often treated with 5-fluorouracil (5-FU). However the clinical application of 5-FU was limited by drug resistance in CRC. Photodynamic therapy (PDT) is a novel treatment combating CRC via the combination of photosensitizer, molecular oxygen and light activation. In this study, 5-FU resistant HT29 (HT29FU) was established and its susceptibility to Foslip® PDT tested. Effect of 5-FU to HT29 cells was measured via qPCR. Efficacy of Foslip® PDT on HT29 and HT29FU cells were measured via photosensitizer uptake, cellular localization, cytotoxicity, cell cycle distribution and signal proteins expression. 5-FU significantly induced ABCB1 mRNA expression in HT29 cells; whereas with a 24 fold increase in HT29FU cells. Both cells responded similarly to Foslip® PDT, with the inhibitory concentration IC20, IC50 and IC70 achieved at 1 ng/mL, 2 ng/mL and 5 ng/mL with 2 J/cm2 light activation respectively. Foslip® PDT triggered apoptosis and reduced JNK protein expression at IC70 on both cells. Effect of Foslip® PDT on HT29 cells was independent to 5-FU resistance properties. Therefore, Foslip® PDT could be a potential treatment for 5-FU resistant cancer patients. Further investigations on the Foslip® PDT mediated molecular changes in HT29FU cells deserve to be explored.