Expression Of ATP-binding Cassette Transporters Research Articles

APC Loss Prevents Doxorubicin-Induced Cell Death by Increasing Drug Efflux and a Chemoresistant Cell Population in Breast Cancer.

Chemoresistance is a major health concern affecting cancer patients. Resistance is multifactorial, with one mechanism being the increased expression of ABC transporters (such as MDR1 and MRP1), which are drug efflux transporters capable of preventing intracellular accumulation of drugs and cell death. Our lab showed that the loss of Adenomatous Polyposis Coli (APC) caused an intrinsic resistance to doxorubicin (DOX), potentially through an enhanced tumor-initiating cell (TIC) population and the increased activation of STAT3 mediating the expression of MDR1 in the absence of WNT being activated. Here, in primary mouse mammary tumor cells, the loss of APC decreased the accumulation of DOX while increasing the protein levels of MDR1 and MRP1. We demonstrated decreased APC mRNA and protein levels in breast cancer patients compared with normal tissue. Using patient samples and a panel of human breast cancer cell lines, we found no significant trend between APC and either MDR1 or MRP1. Since the protein expression patterns did not show a correlation between the ABC transporters and the expression of APC, we evaluated the drug transporter activity. In mouse mammary tumor cells, the pharmacological inhibition or genetic silencing of MDR1 or MRP1, respectively, decreased the TIC population and increased DOX-induced apoptosis, supporting the use of ABC transporter inhibitors as therapeutic targets in APC-deficient tumors.

Novel differential calcium regulation of hematopoietic stem and progenitor cells under physiological low oxygen conditions.

Low oxygen bone marrow (BM) niches (~1%-4% low O2 ) provide critical signals for hematopoietic stem/progenitor cells (HSC/HSPCs). Our presented data are the first to investigate live, sorted HSC/HSPCs in their native low O2 conditions. Transcriptional and proteomic analysis uncovered differential Ca2+ regulation that correlated with overlapping phenotypic populations consisting of robust increases of cytosolic and mitochondrial Ca2+ , ABC transporter (ABCG2) expression and sodium/hydrogen exchanger (NHE1) expression in live, HSC/HSPCs remaining in constant low O2. We identified a novel Ca2+ high population in HSPCs predominantly detected in low O2 that displayed enhanced frequency of phenotypic LSK/LSKCD150 in low O2 replating assays compared to Ca2+ low populations. Inhibition of the Ca2+ regulator NHE1 (Cariporide) resulted in attenuation of both the low O2 induced Ca2+ high population and subsequent enhanced maintenance of phenotypic LSK and LSKCD150 during low O2 replating. These data reveal multiple levels of differential Ca2+ regulation in low O2 resulting in phenotypic, signaling, and functional consequences in HSC/HSPCs.

Abstract 408: Novel growth hormone receptor antagonist with discrete PEGylations markedly improve response to therapy in human pancreatic and bile duct cancers in mice

Abstract Here we present a new and improved GHR antagonist candidate (compound G) with novel discrete PEGylations exhibiting marked efficacy in synergizing anti-cancer therapies. The American Cancer Society estimates the 5-year survival rates of pancreatic adenocarcinoma (PAAD) and bile duct cancer/cholangiocarcinoma (CHOL) to be a dismal 10% in 2022, indicating an urgent need for new therapeutic approaches for both of these devastating diseases. Several human cancers, including PAAD and CHOL express two validated oncological targets - the growth hormone receptor (GHR) and the insulin-like growth factor 1 receptor (IGF1R), as well as their cognate ligands growth hormone (GH) and insulin-like growth factor 1 (IGF1), respectively. Our laboratory had pioneered the discovery of pharmacologic antagonists for the growth hormone receptor (GHR), including the only approved and prescribed GHR antagonist, pegvisomant (Pfizer), prescribed for acromegaly (a condition of excess GH due to a hypersecreting pituitary adenoma). GHR antagonists not only inhibit the effects of GH but also robustly suppress the production of IGF1. The novel GHR antagonist compound G, that we present here, has a greater binding affinity than Pegvisomant to the GHR. And unlike Pegvisomant, compound G binds to the prolactin receptor as well as the GHR. A large body of research by us and others have earlier shown that the covert actions of tumoral GHR and IGF1R activation collectively drive mechanisms of therapy resistance including, but not limited to, active multidrug efflux, activation of epithelial-to-mesenchymal transition (EMT), resistance to apoptosis, increased fibrosis, increase of cancer stem cells, tumor angiogenesis and senescence. Our novel discrete PEGylated GHR antagonist, compound G, alone exhibits significant suppression of cancer cell viability, invasive potential, and drug efflux rate in PAAD and CHOL cell cultures. In Nude mice with human PAAD or CHOL xenografts, GHR inhibition by compound-G markedly sensitized the tumors towards both low and high doses of gemcitabine (for PAAD) or gemcitabine-cisplatin (for CHOL) treatments. Compound-G in combination with chemotherapy resulted in markedly reduced tumor sizes in all CHOL and PAAD mice and almost complete tumor clearance in 40% of the mice with PAAD. In the GHR antagonist treated tumors, significantly lower expression of ABC transporters (Abcb1, Abcg5, Abcc2, Abcg2), EMT mediators (Cdh2, Zeb1, Snai2, Epas1) and apoptosis marker (Bcl2) genes compared to control were observed - accounting for the molecular mechanisms underlying the observed effects. Collectively, our data provide a robust pre-clinical validation for treatment regimens combining GHR antagonist and chemotherapy leading to highly efficacious tumor clearance. Citation Format: Reetobrata Basu, John J. Kopchick. Novel growth hormone receptor antagonist with discrete PEGylations markedly improve response to therapy in human pancreatic and bile duct cancers in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 408.

Effect of Polyunsaturated Fatty Acids on Temozolomide Drug-Sensitive and Drug-Resistant Glioblastoma Cells.

Glioblastomas (GBMs) are notoriously difficult to treat, and the development of multiple drug resistance (MDR) is common during the course of the disease. The polyunsaturated fatty acids (PUFAs) gamma-linolenic acid (GLA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) have been reported to improve MDR in several tumors including breast, bladder, and leukaemia. However, the effects of PUFAs on GBM cell MDR are poorly understood. The present study investigated the effects of PUFAs on cellular responses to temozolomide (TMZ) in U87MG cells and the TMZ-resistant (TMZR) cells derived from U87MG. Cells were treated with PUFAs in the absence or presence of TMZ and dose-response, viable cell counting, gene expression, Western blotting, flow cytometry, gas chromatography-mass spectrometry (GCMS), and drug efflux studies were performed. The development of TMZ resistance caused an increase in ABC transporter ABCB1 and ABCC1 expression. GLA-, EPA-, and DHA-treated cells had altered fatty acid composition and accumulated lipid droplets in the cytoplasm. The most significant reduction in cell growth was seen for the U87MG and TMZR cells in the presence of EPA. GLA and EPA caused more significant effects on ABC transporter expression than DHA. GLA and EPA in combination with TMZ caused significant reductions in rhodamine 123 efflux from U87MG cells but not from TMZR cells. Overall, these findings support the notion that PUFAs can modulate ABC transporters in GBM cells.

Modulatory Activity of the Copper Chelate, Copper N-(2-Hydroxy Acetophenone) Glycinate, in ABC-transporter-expressing Cell Lines.

Metal-containing compounds (e.g., platinum complexes) belong to the standard armamentarium of cancer chemotherapy. Copper N-(2-hydroxy acetophenone) glycinate (CuNG) exerts anticancer activity in vitro and in vivo and modulates drug resistance related to glutathione or P-glycoprotein. The potential of CuNG to interact with ATP-binding cassette (ABC) transporters has not been fully explored yet. This study focused on the modulatory effects of CuNG on four ABC transporters (MRP1, MRP1, BCRP, and P-glycoprotein). Cell viability, drug uptake and ABC transporter expression were measured by resazurin assays, flow cytometry, and ELISA in HL60AR, MDCKII-hBCRP, and Caco-2 cells. CuNG increased doxorubicin sensitivity of MRP1-over-expressing HL60AR with a similar efficacy as the control MRP1 inhibitor MK571. CuNG also increased MRP1's efflux activity. Comparable results were obtained with MDCKII cells over-expressing hBCRP. ELISA assays revealed that the expression of MRP1 in HL60AR cells and BCRP in MDCKII- cells was predominant but other ABC-transporters were also expressed at lower levels. Caco-2 cells expressed high levels of MRP2, but MRP1, BCRP, and P-glycoprotein were also expressed. In contrast to the two former cell lines, CuNG increased doxorubicin resistance and decreased efflux activity in Caco-2 cells. CuNG exerted different modulatory activities towards ABC-transporter-expressing cells. While CuNG-mediated ABC-transporter inhibition may improve tumor chemotherapy (like in HL60AR and MDCKII-hBCRP cells), CuNG-mediated enhanced ABC-transport (like in Caco-2 cells) may be a new strategy to ameliorate inflammatory diseases associated with decreased ABC-transporter expression such as ulcerative colitis.

IOX-1 suppresses metastasis of osteosarcoma by upregulating histone H3 lysine trimethylation

New therapeutic approaches are needed for metastatic osteosarcoma (OS), as survival rates remain low despite surgery and chemotherapy. Epigenetic changes, such as histone H3 methylation, play key roles in many cancers including OS, although the underlying mechanisms are not clear. In this study, human OS tissue and OS cell lines displayed lower levels of histone H3 lysine trimethylation compared with normal bone tissue and osteoblast cells. Treating OS cells with the histone lysine demethylase inhibitor 5-carboxy-8-hydroxyquinoline (IOX-1) dose-dependently increased histone H3 methylation and inhibited cellular migratory and invasive capabilities, suppressed matrix metalloproteinase expression, reversed epithelial-to-mesenchymal transition by increasing levels of epithelial markers E-cadherin and ZO-1 and decreasing the expression of mesenchymal markers N-cadherin, vimentin, and TWIST, and also reduced stemness properties. An analysis of cultivated MG63 cisplatin-resistant (MG63-CR) cells revealed lower histone H3 lysine trimethylation levels compared with levels in MG63 cells. Exposing MG63-CR cells to IOX-1 increased histone H3 trimethylation and ATP-binding cassette transporter expression, potentially sensitizing MG63-CR cells to cisplatin. In conclusion, our study suggests that histone H3 lysine trimethylation is associated with metastatic OS and that IOX-1 or other epigenetic modulators present promising strategies to inhibit metastatic OS progression.

Transcriptomic analysis reveals differential adaptation of colorectal cancer cells to low and acute doses of cisplatin

Over the years, the landscape of cisplatin-based cancer treatment options has undergone continuous transitions. Currently, there is much debate over the optimum dose of cisplatin to be administered to cancer patients. In clinical practice, it can extend from repeated low sub-toxic doses to a few cycles of acute high drug doses. Herein, the molecular understanding of the overall cellular response to such differential doses of cisplatin becomes crucial before any decision making; and it has been a grey area of research. In this study, colorectal cancer (CRC) cells were treated with either- a low sub-toxic dose (LD; 30 µM) or a ten times higher acute dose (HD; 300 µM) of cisplatin, and thereafter, the cellular response was mapped through RNA sequencing followed by transcriptomic analysis. Interestingly, we observed that the tumor cells’ response to varying doses of cisplatin is distinctly different, and they activate unique transcriptional programs. The analysis of differentially regulated or uniquely expressed transcripts and corresponding pathways revealed a preferential enrichment of genes associated with chromatin organization, oxidative stress, senescence-associated signaling, and developmentally-active signaling pathways in HD; whereas, modulation of autophagy, protein homeostasis, or differential expression of ABC transporters was primarily enriched in LD. This study is the first of its kind to highlight cellular transcriptomic adaptations to different doses of cisplatin in CRC cells. Consequently, since, protein homeostasis was found to be deeply affected after cisplatin treatment, we further analyzed one of the primary cellular protein homeostatic mechanisms- autophagy. It was activated upon LD, but not HD, and served as a pro-survival strategy through the regulation of oxidative stress. Inhibition of autophagy improved sensitivity to LD. Overall, our study provides a holistic understanding of the distinct molecular signatures induced in CRC cells in response to differential cisplatin doses. These findings might facilitate the design of tailored therapy or appropriate drug dose for enhanced efficacy against CRCs.

Regulation of Multidrug Efflux Pumps by TetR Family Transcriptional Repressor Negatively Affects Secondary Metabolism in Streptomyces coelicolor A3(2).

Streptomyces spp. are well-known producers of bioactive secondary metabolites (SMs) that serve as pharmaceutical agents. In addition to their ability to produce SMs, Streptomyces spp. have evolved diverse membrane transport systems to protect cells against antibiotics produced by itself or other microorganisms. We previously screened mutants of Streptomyces coelicolor that show a phenotype of reduced undecylprodigiosin (RED) production in a combined-culture with Tsukamurella pulmonis. Here, we identified a point mutation, which reduced RED production, by performing genome resequencing and genetic complementation. We found that inactivation of the sco1718 gene encoding the TetR family transcriptional regulator (TFR) produced a deficient phenotype for several SMs in Streptomyces coelicolor A3(2). In the genome of S. coelicolor A3(2), two other sets of TFR and two-component ATP-binding cassette (ABC) transporter genes (sco4358-4360 and sco5384-5382) were found which had similar effects on the phenotype for both secondary metabolism and antibiotic resistance. An electrophoretic mobility shift assay and quantitative reverse transcription-PCR experiments demonstrated that TFRs repressed the expression of each adjacent two-component ABC transporter genes by binding to the operator sequence. Notably, the Δsco1718 mutant showed increased resistance to several antibiotics of other actinomycete origin. Our results imply the switching of cell metabolism to direct offense (antibiotic production) or defense (efflux pump activation) using costly and limited quantities of cell energy sources (e.g., ATP) in the soil ecosystem. IMPORTANCE The bacterial metabolic potential to synthesize diverse secondary metabolites in the environment has been revealed by recent (meta)genomics of both unculturable and culturable bacteria. These studies imply that bacteria are continuously exposed to harmful chemical compounds in the environment. Streptomyces spp. contain antibiotic efflux pumps and SM biosynthetic gene clusters. However, the mechanism by which soil bacteria, including Streptomyces, survive against toxic compounds in the environment remains unclear. Here, we identified three sets of TFR-ABC transporter genes in Streptomyces coelicolor A3(2). We found that each TFR controlled the expression of respective ABC transporter, and the expression of all ABC transporters negatively impacted SM production and increased antibiotic resistance. Notably, bioinformatic analysis indicated that these TFR-ABC transporter gene sets are highly conserved and widely distributed in the genome of Streptomyces species, indicating the importance of systematic regulation that directs antibiotic production and xenobiotic excretion.

Semi-Synthetic Dihydrotestosterone Derivatives Modulate Inherent Multidrug Resistance and Sensitize Colon Cancer Cells to Chemotherapy

Multidrug resistance (MDR) is a serious hurdle to successful cancer therapy. Here, we examined the efficiency of novel semi-synthetic dihydrotestosterone derivatives, more specifically androstano-arylpyrimidines in inhibiting the efflux activity of ATP-binding cassette (ABC) transporters and sensitizing inherently MDR colon cancer cells to various chemotherapy drugs. Using the Rhodamine123 accumulation assay, we evaluated the efflux activity of cancer cells following treatments with androstano-arylpyrimidines. We found that acetylated compounds were capable of attenuating the membrane efflux of inherently MDR cells; however, deacetylated counterparts were ineffective. To delineate the possible molecular mechanisms underlying these unique activities of androstano-arylpyrimidines, the degree of apoptosis induction was assessed by AnnexinV-based assays, both upon the individual as well as by steroid and chemotherapy agent combination treatments. Five dihydrotestosterone derivatives applied in combination with Doxorubicin or Epirubicin triggered massive apoptosis in MDR cells, and these combinations were more efficient than chemotherapy drugs together with Verapamil. Furthermore, our results revealed that androstano-arylpyrimidines induced significant endoplasmic reticulum stress (ER stress) but did not notably modulate ABC transporter expression. Therefore, ER stress triggered by acetylated androstano-arylpyrimidines is probably involved in the mechanism of efflux pump inhibition and drug sensitization which can be targeted in future drug developments to defeat inherently multidrug-resistant cancer.

Characterization of cadmium accumulation mechanism between eggplant (Solanum melongena L.) cultivars.

Excessive cadmium (Cd) accumulation in vegetables due to farmland pollution constitutes a serious threat to human health. Eggplant has a tendency to accumulate Cd. To investigate the mechanism of the differences in Cd accumulation levels between high-Cd (BXGZ) and low-Cd (MYQZ) eggplant cultivar, physiological and biochemical indicators and mRNA expression of eggplant were examined using photosynthetic apparatus, biochemical test kits, Fourier transform infrared (FTIR) spectroscopy and transcriptome sequencing, etc. The results of biochemical test kits and FTIR revealed that MYQZ enhanced pectin methylesterase (PME) activity, and lignin and pectin content in the root cell wall, which was associated with the upregulation of PME, cinnamyl-alcohol dehydrogenase and peroxidase (PODs). Higher levels of cysteine and glutathione (GSH) contents and upregulation of genes associated with sulfur metabolism, as well as higher expression of ATP-binding cassette transporters (ABCs), cation exchangers (CAX) and metal tolerance proteins (MTPs) were observed in MYQZ. In BXGZ, the higher stomatal density and stomatal aperture as well as higher levels of Ca2+ binding protein-1 (PCaP1) and aquaporins and lower levels of A2-type cyclins (CYCA2-1) are consistent with an enhanced transpiration rate in BXGZ. Furthermore, a more developed root system was shown to be associated with higher levels of auxin response factor (ARF19), GATA transcription factors (GATA4, 5 and 11) and auxin efflux carrier component (PIN5) in BXGZ. In conclusion, highly active PME, and higher levels of lignin and pectin in MYQZ are expected to reduce Cd toxicity, while Cd translocation can be inhibited with the help of ABC and other Cd transporters. As for BXGZ, the uptake and translocation of Cd were enhanced by the developed root system and stronger transpiration.

Maternal and Fetal Expression of ATP-Binding Cassette and Solute Carrier Transporters Involved in the Brain Disposition of Drugs.

Evidence from preclinical and clinical studies demonstrate that pregnancy is a physiological state capable of modifying drug disposition. Factors including increased hepatic metabolism and renal excretion are responsible for impacting disposition, and the role of membrane transporters expressed in biological barriers, including the placental- and blood-brain barriers, has received considerable attention. In this regard, the brain disposition of drugs in the mother and fetus has been the subject of studies attempting to characterize the mechanisms by which pregnancy could alter the expression of ATP-binding cassette (ABC) and solute carrier (SLC) transporters. This chapter will summarize findings of the influence of pregnancy on the maternal and fetal expression of ABC and SLC transporters in the brain and the consequences of such changes on the disposition of therapeutic drugs.

Bixin and Fuxoxanthin Alone and in Combination with Cisplatin Regulate ABCC1 and ABCC2 Transcription in A549 Lung Cancer Cells.

The ATP-Binding Cassette (ABC) transporter has long been studied to confer drug resistance in human tumors and play important role in metabolic processes and cellular signaling. The overexpression of ABCB1, ABCC1, ABCC2, ABCC3, and ABCG2 leads to decreased sensitivity of lung cancer to cisplatin. At the transcription level, the expression of ABC transporters is highly regulated and requires the complex interplay of factors involved in differentiation and development, cell survival and apoptosis upon intrinsic and environmental stress. The p53 regulation of drug-resistance genes is also complex yet not well understood. Previously, we demonstrated the synergistic interaction between bixin or fucoxanthin with cisplatin in A549 lung cancer cells. Current study aims to identify whether carotenoids enhancing therapeutic effect of Cisplatin due to the ability to reverse drug resistance associated proteins, such as ABC transporter and regulating the tumor suppressor corresponding gene, p53. Real-Time Quantitative-Polymerase Chain Reaction (RT-qPCR) was performed to estimate the expression level of ABCC1 and ABCC2, and p53 of A549 cell lines in response to carotenoids alone and in combination with cisplatin. The administration of bixin or fucoxanthin decreases the expression of ABCC1 and ABCC2. Both carotenoids, either alone or in combination with cisplatin, upregulated p53 gene expression indicating the mechanism of proliferation inhibition and apoptosis occurs via the p53 caspase-independent pathway.

ABC transporters affects tumor immune microenvironment to regulate cancer immunotherapy and multidrug resistance.

Multidrug resistance (MDR) is the phenomenon in which cancer cells simultaneously develop resistance to a broad spectrum of structurally and mechanistically unrelated drugs. MDR severely hinders the effective treatment of cancer and is the major cause of chemotherapy failure. ATP-binding cassette (ABC) transporters are extensively expressed in various body tissues, and actively transport endogenous and exogenous substrates through biological membranes. Overexpression of ABC transporters is frequently observed in MDR cancer cells, which promotes efflux of chemotherapeutic drugs and reduces their intracellular accumulation. Increasing evidence suggests that ABC transporters regulate tumor immune microenvironment (TIME) by transporting various cytokines, thus controlling anti-tumor immunity and sensitivity to anticancer drugs. On the other hand, the expression of various ABC transporters is regulated by cytokines and other immune signaling molecules. Targeted inhibition of ABC transporter expression or function can enhance the efficacy of immune checkpoint inhibitors by promoting anticancer immune microenvironment. This review provides an update on the recent research progress in this field.

Noval bio-organic fertilizer containing Arthrobacter sp. DNS10 alleviates atrazine-induced growth inhibition on soybean by improving atrazine removal and nitrogen accumulation

Herbicide atrazine restricts nutrient accumulation and thus inhibits the growth of sensitive crops. The application of organic fertilizer is a common measure that contributes to modulating abiotic tolerance of crops and providing nutrients, but its advantages in combination with atrazine degrading microorganisms as bio-organic fertilizer to alleviate atrazine stress on sensitive crops and the associated mechanisms are unknown. We investigated the beneficial effects of organic and bio-organic fertilizer (named DNBF10) containing Arthrobacter sp. DNS10 applications on growth, leaf nitrogen accumulation, root surface structure and root physiological properties of soybean seedlings exposed to 20 mg kg−1 atrazine in soil. Compared with organic fertilizer, bio-organic fertilizer DNBF10 exhibited more reduction in soil atrazine residue and plant atrazine accumulation, as well as alleviation in atrazine-induced root oxidative stress and damaged cells of soybean roots. Transcriptome analysis revealed that DNBF10 application enhanced nitrogen utilization by improving the expression of genes involved in nitrogen metabolism in soybean leaves. Besides, genes expression of cytochrome P450 and ABC transporters involved in atrazine detoxification and transport in soybean leaves were also down-regulated by DNBF10 to diminish phytotoxicity of atrazine to soybean seedlings. These results illustrate the molecular mechanism by which the application of DNBF10 alleviates soybean seedlings growth under atrazine stress, providing a step forward for mitigate the atrazine induced inhibition on soybean seedlings growth through decreasing atrazine residues as well as enhancing damaged root repair and nitrogen accumulation.

Modified Highland Barley Regulates Lipid Metabolism and Liver Injury in High Fat and Cholesterol Diet ICR Mice.

Highland barley (Hordeum vulgare L. HB) has been demonstrated to have a series of dietotherapy values, including being low fat, low sugar, high fiber, and especially high in β-glucan. Long-term consumption could reduce the incidence of chronic diseases and metabolic syndromes. In this study, the regulating effect of modified highland barley (MHB) products, namely microwave fluidized HB, extruded and puffed HB, and ultrafine pulverized HB on lipid metabolism and liver injury in mice fed a high fat and cholesterol diet (HFCD) was investigated using microbiota diversity gene sequencing and untargeted metabolomics. A total of six groups of mice were supplemented with a normal diet or an HFCD, with or without MHB, and the experimental period lasted 10 weeks. The obtained results demonstrated that MHB supplementation could effectively reverse the increase in body weight gain and adipose tissue accumulation caused by an HFCD (p < 0.05). Moreover, serum biochemical parameters showed that MHB supplementation significantly decreased total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) levels, while increasing high-density lipoprotein cholesterol (HDL-C) levels. The results of hematoxylin and eosin (H&E) assays showed that MHB supplementation could significantly improve the liver injury and adipose tissue accumulation. In addition, 16S rRNA amplicon sequencing showed that MHB supplementation increased the bacteroidetes/firmicutes ratio and the abundance Lactobacillus abundance, while also decreasing the Proteobacteria abundance, which are bacteria closely associated with the hyperlipidemia caused by HFCD. LC-MS metabolomics indicated that MHB supplementation significantly enhanced the levels of Deoxycholic acid, Myclobutanil, 3-Epiecdysone, 3,4-Dihydroxybenzeneacetic acid, and so on. In addition, MHB supplementation promoted activation of the Arachidonic acid metabolism pathways, the expression of ABC transporters, bile secretion, primary bile acid biosynthesis, and so on. Above all, this study showed the potential capacity of MHB to relieve hyperlipidemia and provides a reference for developing a new dietary intervention supplement to ameliorate hyperlipidemia.

Integrated analysis of transcriptomics and metabolomics in human hepatocellular carcinoma HepG2215 cells after YAP1 knockdown

Yes-associated protein 1 (YAP1) plays a critical role in hepatocellular carcinoma (HCC). Inhibition of YAP1 expression suppresses HCC progression, but the underlying mechanism is still unclear. In this study, we studied the effects and molecular mechanisms of YAP1 knockdown on the growth and metabolism in human HCC HepG2215 cells. Inhibition of YAP1 expression inhibits the proliferation and metastasis in HepG2215 cells, and differentially expressed genes (DEGs) and metabolites were identified in shYAP1-HepG2215 cells. Further, 805 DEGs, mainly associated with metabolism and particularly lipid metabolism, were identified by transcriptome sequencing analyses in shYAP1-HepG2215 cells. YAP1 knockdown increased albumin (ALB) levels by Protein-protein interaction (PPI) network analyses in HepG2215 cells. Metabolomic profiling identified 37 metabolites with significant differences in the shYAP1 group, and amino acid metabolism generally decreased in the shYAP1 group. Comprehensive analysis of transcriptomics and metabolomics revealed that the ATP-binding cassette (ABC) transporters play a central role after YAP1 knockdown in HepG2215 cells. Therefore, YAP1 knockdown inhibited HCC growth, which affected the metabolism of lipids and amino acids by regulating the expression of ALB and ABC transporters in HepG2215 cells.

Talazoparib Does Not Interact with ABCB1 Transporter or Cytochrome P450s, but Modulates Multidrug Resistance Mediated by ABCC1 and ABCG2: An in Vitro and Ex Vivo Study.

Talazoparib (Talzenna) is a novel poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitor that is clinically used for the therapy of breast cancer. Furthermore, the drug has shown antitumor activity against different cancer types, including non-small cell lung cancer (NSCLC). In this work, we investigated the possible inhibitory interactions of talazoparib toward selected ATP-binding cassette (ABC) drug efflux transporters and cytochrome P450 biotransformation enzymes (CYPs) and evaluated its position in multidrug resistance (MDR). In accumulation studies, talazoparib interacted with the ABCC1 and ABCG2 transporters, but there were no significant effects on ABCB1. Furthermore, incubation assays revealed a negligible capacity of the tested drug to inhibit clinically relevant CYPs. In in vitro drug combination experiments, talazoparib synergistically reversed daunorubicin and mitoxantrone resistance in cells with ABCC1 and ABCG2 expression, respectively. Importantly, the position of an effective MDR modulator was further confirmed in drug combinations performed in ex vivo NSCLC patients-derived explants, whereas the possible victim role was refuted in comparative proliferation experiments. In addition, talazoparib had no significant effects on the mRNA-level expressions of MDR-related ABC transporters in the MCF-7 cellular model. In summary, our study presents a comprehensive overview on the pharmacokinetic drug-drug interactions (DDI) profile of talazoparib. Moreover, we introduced talazoparib as an efficient MDR antagonist.

New mechanistic insights into PAHs transport across wheat root cell membrane: Evidence for ABC transporter mediation

Polycyclic aromatic hydrocarbons (PAHs) are a class of highly carcinogenic organic pollutants. Our previous results revealed that the active uptake of PAHs by plant roots is performed through H+/PAHs co-transport. However, the proteins and mechanisms of co-transport of PAHs remain unknown. We hypothesized that ABC transporters are involved in PAHs co-transport via the roots. We found a total of 47 ABC transporters with alkalinity and hydrophobicity which were up-regulated or newly expressed in the wheat roots after phenanthrene exposure. And the concentration of ABC transporters rose. There was a positive relationship between the concentration of phenanthrene and ABC transporter expression in the wheat roots. Additionally, the trend observed in the ABC transporters expression was also found in the gene expression. With energies below −6 kcal mol−1, a stable docking conformation formed between ABC transporters and PAHs. π-π stacking and van der Waals force bound PAHs to ABCB or ABCG. The binding strength of ABCB subfamily proteins with homodimers is stronger than that of ABCG subfamily proteins with single molecules. ABC transporters may transport PAHs by forming a dimer-shaped pocket, translocating it into cells, then opening it within the cells, to release the bound PAHs. These results contributed to our understanding of how ABC transporters aid plant root uptake of PAHs.

Physiological and transcriptomic study reveal SeNPs-mediated AsIII stress detoxification mechanisms involved modulation of antioxidants, metal transporters, and transcription factors in Glycine max L. (Merr.) roots

Physiological changes and genome-wide alteration in gene expression were performed in soybean (Glycine max [L.] Merr.) roots exposed to AsⅢ (25 μmol/L) alone and supplemented with selenium nanoparticles (SeNPs) at the concentration of 10 and 25 μmol/L at the V2 growth stage. Excessive arsenic in the root zone poses a potential threat to soybean yield, particularly to roots, due to the limited translocation of AsIII from root to shoot in the case of soybean. We hypothesized that SeNPs can relieve AsⅢ toxicity to soybean root by reducing the AsⅢ uptake and regulating the internal tolerance mechanism of the plants. Results accomplished that SeNPs had positive impact on soybean dry weight and roots parameters under AsⅢ stress. Then, we further evaluated physiological indexes, whole genome transcriptomic analysis and quantitative real-time PCR to elucidate the underlying mechanism of AsⅢ tolerance under SeNPs supplementation. Under the condition of AsⅢ-stress, SeNPs exposure significantly reduced the electrolyte leakage, O2−•, H2O2 and MDA accumulation while increasing the antioxidants level. The RNA-seq dataset revealed total of 5819 up and 7231 down expressed DEGs across all libraries. The number of exclusively regulated genes were higher under As + SeNP10 (4909) treatment than in the AsⅢ-alone (4830) and As + SeNP25 (3311) treatments. The KEGG and GO analyses revealed that stress responsive DEGs such as glutathione S-transferase, glutathione peroxidase, ascorbate, glutaredoxin, thioredoxin, and phytochelatins synthase are responsible for AsⅢ tolerance under the SeNPs supplementation. Similarly, sulfate transporter, and ABC transporters (ATP-binding cassettes) expression were induced, and aquaporin channels related DEGs expression were reduced under SeNPs application in AsⅢ exposure condition. Furthermore, the expression of molecular chaperones (HSP) and transcription factors (MYB, bZIP, bHLH, and HSFs) were increased in SeNPs treatment groups. These results provide vital information of AsⅢ tolerance mechanism in response to SeNPs in soybean. We suggest that functional characterization of these genes will help us learn more about the SeNPs responsive arsenic tolerance mechanism in soybean.

Protein Expression of Amino Acid Transporters Is Altered in Isolated Cerebral Microvessels of 5xFAD Mouse Model of Alzheimer’s Disease

Membrane transporters such as ATP-binding cassette (ABC) and solute carrier (SLC) transporters expressed at the neurovascular unit (NVU) play an important role in drug delivery to the brain and have been demonstrated to be involved in Alzheimer’s disease (AD) pathogenesis. However, our knowledge of quantitative changes in transporter absolute protein expression and functionality in vivo in NVU in AD patients and animal models is limited. The study aim was to investigate alterations in protein expression of ABC and SLC transporters in the isolated brain microvessels and brain prefrontal cortices of a widely used model of familial AD, 5xFAD mice (8 months old), using a sensitive liquid chromatography tandem mass spectrometry-based quantitative targeted absolute proteomic approach. Moreover, we examined alterations in brain prefrontal cortical and plasmatic levels of transporter substrates in 5xFAD mice compared to age-matched wild-type (WT) controls. ASCT1 (encoded by Slc1a4) protein expression in the isolated brain microvessels and brain prefrontal cortices of 5xFAD mice was twice higher compared to WT controls (p = 0.01). Brain cortical levels of ASCT1 substrate, serine, were increased in 5xFAD mice compared to WT animals. LAT1 (encoded by Slc7a5) and 4F2hc (encoded by Slc3a2) protein expressions were significantly altered in the isolated brain microvessels of 5xFAD mice compared to WT controls (p = 0.008 and p = 0.05, respectively). Overall, the study provides important information, which is crucial for the optimal use of the 5xFAD mouse model in AD drug development and for investigating novel drug delivery approaches. In addition, the findings of the study shed light on the novel potential mechanisms underlying AD pathogenesis.