Expression Of ATP-binding Cassette Transporters Research Articles

Multidrug-Resistant Profiles in Non-Small Cell Lung Carcinoma Patient-Derived Cells: Implications for Personalized Approaches with Tyrosine Kinase Inhibitors

The impact of tyrosine kinase inhibitors (TKIs) on multidrug resistance (MDR) in non-small cell lung carcinoma (NSCLC) is a critical aspect of cancer therapy. While TKIs effectively target specific signaling pathways of cancer cells, they can also act as substrates for ABC transporters, potentially triggering MDR. The aim of our study was to evaluate the response of 17 patient-derived NSCLC cultures to 10 commonly prescribed TKIs and to correlate these responses with patient mutational profiles. Using an ex vivo immunofluorescence assay, we analyzed the expression of the MDR markers ABCB1, ABCC1, and ABCG2, and correlated these data with the genetic profiles of patients for a functional diagnostic approach. NSCLC cultures responded differently to TKIs, with erlotinib showing good efficacy regardless of mutation burden or EGFR status. However, the modulation of MDR mechanisms by erlotinib, such as increased ABCG2 expression, highlights the challenges associated with erlotinib treatment. Other TKIs showed limited efficacy, highlighting the variability of response in NSCLC. Genetic alterations in signaling pathways associated with drug resistance and sensitivity, including TP53 mutations, likely contributed to the variable responses to TKIs. The relationships between ABC transporter expression, gene alterations, and response to TKIs did not show consistent patterns. Our results suggest that in addition to mutational status, performing functional sensitivity screening is critical for identifying appropriate treatment strategies with TKIs. These results underscore the importance of considering drug sensitivity, off-target effects, MDR risks, and patient-specific genetic profiles when optimizing NSCLC treatment and highlight the potential for personalized approaches, especially in early stages.

Induction effect of antiretroviral bictegravir on the expression of Abcb1, Abcg2 and Abcc1 genes associated with P-gp, Bcrp and Mrp1 transporters present in rat peripheral blood mononuclear cells

ABSTRACT Background Antiretrovirals have the potential to cause drug interactions leading to inefficacyor toxicity via activation of efflux transporters through nuclear receptors,altering drug concentrations at their target sites. ResearchDesign and Methods This study used molecular dynamicsimulations and qRT-PCR to investigate bictegravir’s interactions with nuclearreceptors Pxr and Car, and its effects on efflux transporters (P-gp, Bcrp,Mrp1) in rat PBMCs. PBMC/plasma drug concentrations were measured usingLC-MS/MS to assess the functional impact of transporter expression. Results Bictegravir significantly increased the expression of ABC transporters, withCar identified as a key mediator. This suggests that bictegravir’s influence onnuclear receptors could affect drug transport and efficacy at the cellularlevel. Conclusions Bictegravir activates nuclear receptors enhancing efflux transporterexpression. Understanding these interactions is crucial for preventing drug-druginteractions and reducing toxicity in clinical use. Combining Car antagonistswith bictegravir may prevent drug resistance and toxicity. However, thesefindings are based on preclinical data and necessitate further clinical trialsto confirm their applicability in clinical settings.

Molecular detection of lacrimal apparatus and ocular surface - related ABC transporter genes

The ocular system is in constant interaction with the environment and with numerous pathogens. The ATP-binding cassette (ABC) transporters represent one of the largest groups among the transmembrane proteins. Their relevance has been demonstrated for their defense function against biotic and abiotic stress factors, for metabolic processes in tumors and for their importance in the development of resistance to drugs. The aim of this study was to analyze which ABC transporters are expressed at the ocular surface and in the human lacrimal apparatus. Using RT-PCR, all ABC transporters known to date in humans were examined in tissue samples from human cornea, conjunctiva, meibomian glands and lacrimal glands. The RT-PCR analyses revealed the presence of all ABC transporters in the samples examined, although the results for some of the 48 transporters known in human and analyzed were different in the various tissues. The present results provide information on the expression of ABC transporters at the mRNA level on the ocular surface and in the lacrimal system. Their detection forms the basis for follow-up studies at the protein level, which will provide more information about their physiological significance at the ocular surface and in the lacrimal system and which may explain pathological effects such as drug resistance.

Influence of Human Bone Marrow Mesenchymal Stem Cells Secretome from Acute Myeloid Leukemia Patients on the Proliferation and Death of K562 and K562-Lucena Leukemia Cell Lineages.

Leukemias are among the most prevalent types of cancer worldwide. Bone marrow mesenchymal stem cells (MSCs) participate in the development of a suitable niche for hematopoietic stem cells, and are involved in the development of diseases such as leukemias, to a yet unknown extent. Here we described the effect of secretome of bone marrow MSCs obtained from healthy donors and from patients with acute myeloid leukemia (AML) on leukemic cell lineages, sensitive (K562) or resistant (K562-Lucena) to chemotherapy drugs. Cell proliferation, viability and death were evaluated, together with cell cycle, cytokine production and gene expression of ABC transporters and cyclins. The secretome of healthy MSCs decreased proliferation and viability of both K562 and K562-Lucena cells; moreover, an increase in apoptosis and necrosis rates was observed, together with the activation of caspase 3/7, cell cycle arrest in G0/G1 phase and changes in expression of several ABC proteins and cyclins D1 and D2. These effects were not observed using the secretome of MSCs derived from AML patients. In conclusion, the secretome of healthy MSCs have the capacity to inhibit the development of leukemia cells, at least in the studied conditions. However, MSCs from AML patients seem to have lost this capacity, and could therefore contribute to the development of leukemia.

Abstract 1085: Exploiting bioenergetic vulnerabilities in chemotherapy resistant osteosarcoma

Abstract BACKGROUND: Osteosarcoma (OS) is the most common bone cancer in children and young adults. Standard treatment involves chemotherapy and surgical resection, yet nearly 4 in 10 patients experience disease relapse, and almost all of these patients are resistant to additional chemotherapy. Therefore, there is an urgent need to understand the biology of chemo-resistant OS and identify new therapeutic strategies to treat this therapy-resistant disease state. METHODS: Using a CRISPR-Cas9 based lineage tracing system, RNA sequencing, and Seahorse XF assays in chemo-naïve, -resistant, and -released human 143b and patient-derived 173x OS cell lines, we modeled the evolution of chemoresistance and release from the selective pressure of chemotherapy in osteosarcoma. The phenotype of each cell state was assessed through in vitro and ex vivo cell proliferation assays, a comparison of cell viability upon re-challenge to standard-of-care chemotherapy, and comparison of cell viability in response to novel therapies targeting alterations in cell respiration. RESULTS: Chemo-resistant OS cells demonstrate a decrease in expression of proliferation-associated gene pathways and shift their resources toward expression and maintenance of multi-drug resistance ABC transporters. Chemo-released cells maintain elevated expression of ABC transporters while re-activating proliferation. Across the spectrum of chemotherapy exposure, OS cells demonstrate changes in respiratory capacity, with unique bioenergetic phenotypes observed in chemo-naïve, -resistant, and -released cells. CONCLUSIONS: Chemo-resistant and chemo-released OS cells demonstrate unique bioenergetic patterns that correlate with gene expression signatures and growth phenotypes. Evolution imposed by the selective pressure of chemotherapy may render OS cells vulnerable to therapies that disrupt cellular energetics and exploit multi-drug resistant ABC transporters. Citation Format: Valerie U. Nguyen, Laurie Graves, Veronica Colmenares, Abol Macabangon, Casey Syal, Kelsey Fisher-Wellman, William C. Eward, So Young Kim, Jason A. Somarelli. Exploiting bioenergetic vulnerabilities in chemotherapy resistant osteosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1085.

Comparison of the impact of saturated fat from full-fat yogurt or low-fat yogurt and butter on cardiometabolic factors: a randomized cross-over trial.

Dairy foods are often a major contributor to dietary saturated fatty acids (SFA) intake. However, different SFA-rich foods may not have the same effects on cardiovascular risk factors. We compared full-fat yogurt with low-fat yogurt and butter for their effects on cardiometabolic risk factors in healthy individuals. Randomized, two-period crossover trial conducted from October 2022 to April 2023 among 30 healthy men and women (15 to receive full-fat yogurt first, and 15 to receive low-fat yogurt and butter first). Participants consumed a diet with 1.5-2 servings of full-fat (4%) yogurt or low-fat (< 1.5) yogurt and 10-15g of butter per day for 4 weeks, with 4 weeks wash-out when they consumed 1.5-2 servings of low-fat milk. At baseline, and the end of each 4 weeks, fasting blood samples were drawn and plasma lipids, glycemic and inflammatory markers as well as expression of some genes in the blood buffy coats fraction were determined. All 30 participants completed the two periods of the study. Apolipoprotein B was higher for the low-fat yogurt and butter [changes from baseline, + 10.06 (95%CI 4.64 to 15.47)] compared with the full-fat yogurt [-4.27 (95%CI, -11.78 to 3.23)] and the difference between two treatment periods was statistically significant (p = 0.004). Non-high-density lipoprotein increased for the low-fat yogurt and butter [change, + 5.06 (95%CI (-1.56 to 11.69) compared with the full-fat yogurt [change, - 4.90 (95%CI, -11.61 to 1.81), with no significant difference between two periods (p = 0.056). There were no between-period differences in other plasma lipid, insulin, and inflammatory biomarkers or leukocyte gene expression of ATP-binding cassette transporter 1 and CD36. This study suggests that short-term intake of SFAs from full-fat yogurt compared to intake from butter and low-fat yogurt has fewer adverse effects on plasma lipid profile. GOV: NCT05589350, 10/15/2022.

TMEM97 knockdown inhibits 5-fluorouracil resistance by regulating epithelial-mesenchymal transition and ABC transporter expression via inactivating the Akt/mTOR pathway in 5-fluorouracil-resistant colorectal cancer cells.

Resistance to 5-fluorouracil (5-FU) is still a primary setback to the success of colorectal cancer (CRC) chemotherapy. Transmembrane protein 97 (TMEM97) functions as an oncogene in CRC. However, the role and mechanism of TMEM97 in regulating 5-FU resistance in CRC cells remains unclear. TMEM97 expression in CRC samples was analyzed by GEPIA and human protein atlas (HPA) databases. TMEM97, E-cadherin, Vimentin, N-cadherin, P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1)/ABCC1, ABCC2, and the changes of protein kinase B/mammalian target of rapamycin (mTOR) pathway were explored by western blot analysis. IC50 value for 5-FU and cell viability was examined by MTT assay. Apoptosis was evaluated by flow cytometry. TMEM97 was highly expressed in colon adenocarcinoma (COAD) and rectum adenocarcinoma (READ) based on GEPIA and HPA databases. TMEM97 knockdown attenuated 5-FU resistance in HCT116/R and SW480/R cells, as evidenced by the reduced IC50 value for 5-FU and the increased apoptosis. TMEM97 knockdown suppressed epithelial-mesenchymal transition (EMT), expression of ATP-binding cassette (ABC) transporters, and the Akt/mTOR pathway. Mechanistically, activation of Akt/mTOR pathway abolished the inhibitory effects of TMEM97 knockdown on 5-FU resistance, EMT, and ABC transporter expression. In conclusion, TMEM97 knockdown inhibited 5-FU resistance in CRC by regulating EMT and ABC transporter expression via inactivating the Akt/mTOR pathway.

ABC transporter expression to predict therapeutic effect of enfortumab vedotin in urothelial cancer.

ABC transporter expression to predict therapeutic effect of enfortumab vedotin in urothelial cancer.

Discovery of Transcription Factors Involved in the Maintenance of Resident Vascular Endothelial Stem Cell Properties.

A resident vascular endothelial stem cell (VESC) population expressing CD157 has been identified recently in mice. Herein, we identified transcription factors (TFs) regulating CD157 expression in endothelial cells (ECs) that were associated with drug resistance, angiogenesis, and EC proliferation. In the first screening, we detected 20 candidate TFs through the CD157 promoter and gene expression analyses. We found that 10 of the 20 TFs induced CD157 expression in ECs. We previously reported that 70% of CD157 VESCs were side population (SP) ECs that abundantly expressed ATP-binding cassette (ABC) transporters. Here, we found that the 10 TFs increased the expression of several ABC transporters in ECs and increased the proportion of SP ECs. Of these 10 TFs, we found that six (Atf3, Bhlhe40, Egr1, Egr2, Elf3, and Klf4) were involved in the manifestation of the SP phenotype. Furthermore, the six TFs enhanced tube formation and proliferation in ECs. Single-cell RNA sequence data in liver ECs suggested that Atf3 and Klf4 contributed to the production of CD157+ VESCs in the postnatal period. We concluded that Klf4 might be important for the development and maintenance of liver VESCs. Our work suggests that a TF network is involved in the differentiation hierarchy of VESCs.

EXTH-32. SYNERGISTIC EFFICACY OF Y BOX BINDING PROTEIN 1 (YBX1) INHIBITION COMBINED WITH CHEMOTHERAPY FOR THE TREATMENT OF MYC-AMPLIFIED MEDULLOBLASTOMA

Abstract Medulloblastoma is the most common pediatric brain tumor in children. Patients diagnosed with MYC-amplified group 3 (G3) have a dismal prognosis with a 5 year survival rate of &amp;lt; 50%. Standard of care consists of maximal resection surgery followed by craniospinal irradiation and chemotherapy, but patients experience diminished quality of life from these extensive treatment regimens. Recent observations have shown that Y-box binding protein 1 (YBX1) is upregulated across human medulloblastoma subgroups compared to normal cerebellum. G3 patient tumors have the highest expression of YBX1, possibly due to an oncogenic feedback loop. We utilized an orthogonal pharmacogenetic approach to target YBX1. Knockdown/out of YBX1 significantly inhibits proliferation of G3 MB cells in vitro and in vivo. We next investigated the therapeutic potential of a novel YBX1 inhibitor, which displays single agent efficacy at decreasing the proliferation of medulloblastoma cell line derived xenografts (CDX). Since YBX1 targeting downregulated ABC transporter expression, we hypothesize that inhibition of YBX1 may sensitize medulloblastoma cells to chemotherapeutic agents. We performed drug synergy experiments combining YBX1 inhibition and commonly used standard of care chemotherapy. We identify that combining YBX1 inhibition sensitizes to both gemcitabine and vincristine in vitro and in vivo. We are currently evaluating this YBX1 inhibitor in an “anchor-probe” screen combining with all currently FDA approved drugs. Our findings impart an alluring prospect of targeting YBX1 in combination with chemotherapy, and possibly other compounds could improve patients’ outcomes.

Cell membrane-camouflaged bufalin targets NOD2 and overcomes multidrug resistance in pancreatic cancer.

Multidrug resistance in pancreatic cancer poses a significant challenge in clinical treatment. Bufalin (BA), a compound found in secretions from the glands of toads, may help overcome this problem. However, severe cardiotoxicity thus far has hindered its clinical application. Hence, the present study aimed to develop a cell membrane-camouflaged and BA-loaded polylactic-co-glycolic acid nanoparticle (CBAP) and assess its potential to counter chemoresistance in pancreatic cancer. The toxicity of CBAP was evaluated by electrocardiogram, body weight, distress score, and nesting behavior of mice. In addition, the anticarcinoma activity and underlying mechanism were investigated both in vitro and in vivo. CBAP significantly mitigated BA-mediated acute cardiotoxicity and enhanced the sensitivity of pancreatic cancer to several clinical drugs, such as gemcitabine, 5-fluorouracil, and FOLFIRINOX. Mechanistically, CBAP directly bound to nucleotide-binding and oligomerization domain containing protein 2 (NOD2) and inhibited the expression of nuclear factor kappa-light-chain-enhancer of activated B cells. This inhibits the expression of ATP-binding cassette transporters, which are responsible for chemoresistance in cancer cells. Our findings indicate that CBAP directly inhibits NOD2. Combining CBAP with standard-of-care chemotherapeutics represents a safe and efficient strategy for the treatment of pancreatic cancer.

Increased Expression of the ABCA1 and ABCA3 Transporter Genes is Associated with Cisplatin Resistance in Breast Cancer Cells.

Breast cancer (BC) is a highly malignant neoplasm with resistance to therapeutics that are related to genes associated with multidrug resistance. The excessive expression of ATP-binding cassette transporters (ABCs) genes, including ABCA1 and ABCA3, is a primary factor contributing to the increased effluent of cell-toxic drugs and subsequent treatment resistance. Therefore, the current work aimed to explore the role of ABCA1 and ABCA3 in chemoresistance activity against cisplatin in breast cancer cells. The current study compared the AMJ13 breast cancer cells derived from a woman Iraqi patient, which are hormone receptor-negative, with MCF-7 breast cancer cells, which are hormone receptor-positive. Cytotoxic assay (CCK-8 assay) is used to measure the cell's viability and cytotoxic activity after it has been treated with cisplatin. Morphological Study using crystal violet stain to examine cytological changes was conducted. Quantitative RT-PCR is used to measure how much the ABCA1, and 3 genes mRNA are being expressed before and after treatment. The CCK-8 assay found that IC50 values of cisplatin in AMJ13 and MCF-7 cells were 202.2 µg/ml and 90.23 µg/ml, respectively. The IC50 value of AMJ13 is 2-fold higher than in MCF-7 cells. The QPCR study revealed that breast cancer cell lines AMJ13 and MCF-7 subjected to cisplatin showed upregulated levels of ABCA1 and ABCA3 expression. Experiments with cytotoxicity assays demonstrate that higher expression of ABCA1 and ABCA3 in AMJ13 and MCF-7 breast cancer cell lines is linked to their resistance. Conclusion: The findings of this study suggest that the ABCA1 and ABCA3 transporters play a significant role in the resistance to cisplatin and,.

I-CBP112 declines overexpression of ATP-binding cassette transporters and sensitized drug-resistant MDA-MB-231 and A549 cell lines to chemotherapy drugs

Despite extensive efforts and ongoing progress in personalized anticancer approaches, chemotherapy remains the first line or the only treatment for some tumors that may develop resistance to chemotherapeutics in time due to inter alia overexpression of ATP-binding cassette transporters. Using clinically-relevant resistant models of triple negative breast cancer (MDA-MB-231; TNBC) as well as non-small cell lung cancer (A549; NSCLC), we tested the efficacy of I-CBP112 – CBP/EP300 bromodomain inhibitor to overcome drug resistance by declining ABC gene transcription. I-CBP112 significantly reduced ABCB1, ABCC1, ABCC2, ABCC3, ABCC5 and ABCG2 in all resistant lines, as well as ABCC10 in TNBC and ABCC4 in paclitaxel-resistant NSCLC, thereby increasing intracellular drug accumulation and cytotoxicity in 2D and 3D cultures. This was phenocopied only by the joint effect of ABC inhibitors such as tariquidar (ABCB1 – P-glycoprotein and ABCG2) and MK-571 (ABCC), whereas single inhibition of ABCB1/ABCG2 or ABCC proteins did not affect drug accumulation, thereby implying the need of simultaneous deficiency in activity of majority of drug pumps for enhanced drug retention. I-CBP112 failed to directly inhibit activity of ABCB1, ABCG2 and ABCC subfamily members at the same time. Importantly, I-CBP112 treated cancer cells polarized human macrophages into proinflammatory phenotypes. Moreover, I-CBP112 remained non-toxic to primary cell lines, nor did it enhance anticancer drug toxicity to blood-immune cells. In silico assay of ADMET properties confirmed the desired pharmacokinetic features of I-CBP112. The results suggest that the CBP/p300 inhibitor is a promising co-adjuvant to chemotherapy in drug-resistant cancer phenotypes, capable of decreasing ABC transporter expression.

Protein expression and localization of ABC transporters in pancreatic adenocarcinoma: Prognostic role of ABCC8

BackgroundATP-binding cassette (ABC) transporters translocate various substances across cellular membranes. Their deregulation may cause cancer drug resistance or perturbations in the supply of building blocks for cancer cells and modify patients’ prognosis. This study investigated protein expression and cellular localization of the previously suggested putative prognostic biomarkers – ABCB2/TAP1, ABCC7/CFTR, ABCC8/SUR1, and ABCD4 in patients with pancreatic ductal adenocarcinoma (PDAC). MethodsProtein expression and localization were assessed by immunohistochemistry in formalin-fixed paraffin-embedded primary tumor tissue blocks of 61 PDAC patients and associated with clinical data and the survival of patients. ResultsNo CFTR protein expression was observed in PDAC, while TAP1 and ABCC8 were expressed predominantly in the cytoplasm of tumor cells. Most samples (81 %) had detectable both membranous and cytoplasmic ABCD4 staining and 42 % had ABCD4 expressed in the apical orientation. Negative membranous ABCD4 staining was significantly more frequent in advanced stage III or IV tumors (p = 0.022). Small or medium counts of individual ABCC8-positive cells in the stroma surrounding tumor tubules were also more often found in stage III or IV (p = 0.044). Patients with moderate or strong ABCC8 cytoplasmic staining intensity in tumor cells had a 3.5-fold higher risk of disease progression than those with weak staining (p = 0.002). ConclusionsThe study shows for the first time that the cytoplasmic ABCC8 protein expression has prognostic value in PDAC.

Regulation of Cholesterol Transporters by Nuclear Receptors

Atherosclerosis is a pathological condition characterized by the accumulation of plaques in the arteries, leading to cardiovascular diseases. The deposition of cholesterol in peripheral cells increases the risk of atherosclerosis. Reverse cholesterol transport (RCT) is essential to reduce the risk of atherosclerosis because it removes excessive cholesterol from the peripheral tissues. ATP-binding cassette transporters such as ABCA1, ABCG1, ABCG5, and ABCG8 are involved in the efflux of cholesterol. The upregulation of these ABC transporters enhances RCT, thereby promoting the removal of excess cholesterol from the body. The expression and activity of ABC transporters are regulated by transcriptional and post-transcriptional mechanisms, as well as by post-translational modifications. In this review, the regulation of ABC transporters by nuclear receptors such as farnesoid X receptor, liver X receptor, retinoid X receptor, retinoic acid receptor, and peroxisome proliferator-activated receptors is discussed. Pharmacological and natural compounds serving as agonists for the nuclear receptors have been identified to elevate the mRNA levels of the transporters. Consequently, it is anticipated that these compounds will attenuate the development of atherosclerosis through stimulation of the ABC transporters, thereby enhancing RCT and fecal cholesterol excretion. Understanding these regulatory processes can aid in the development of therapeutic approaches to prevent atherosclerosis.

P10.28.B INTERMODEL VARIATION OF BBB PERMEABILITY AFFECTS CNS DRUG DELIVERY IN PDX MODELS OF GBM

Abstract BACKGROUND Little progress has been made in the development of effective new therapies for glioblastoma (GBM) the past decades. One of the major obstacles in identifying novel candidate drugs against GBM remains the blood-brain barrier (BBB) and the efflux transporters. Therefore, it is crucial to select drugs able to cross BBB and reach the tumor tissue in therapeutically effective concentrations. In current study, we evaluated the anti-glioma effect of the protein synthesis inhibitor omacetaxine mepesuccinate (OMA) in vitro and its CNS penetrating properties in vivo. MATERIAL AND METHODS The FDA-approved Oncology Drug Set II library was tested on 55 patient-derived GBM cell cultures. We designed a drug shortlisting pipeline combining efficacy data with pharmacodynamic and pharmacokinetic characteristics of each compound. We developed and characterized 3 orthotopic mouse PDX models in terms of brain vascular integrity, BBB permeability and expression of ABC transporters. The PK profile of omacetaxine was assessed in these orthotopic mouse PDX models. RESULTS In vitro, OMA revealed anti-tumor activity at IC50 values well-below reported Cmax plasma value (Cmax=43nM) in approximately 80% of GBM cultures. Unexpectedly, OMA does not downregulate the expression of its acknowledged target, ribosomal protein 3 (RPL3). In glioma cells while activation of caspase 3/7 activity is linked to its anti-tumor effect. OMA is a substrate for ABCB1 (P-glycoprotein) but not for ABCG2 (BCRP). In vivo, dose escalation showed safety of the drug and OMA was found to reach the brain tumor tissue in concentrations similar or higher to the reported IC50 values in vitro, depending on the PDX model used. No adverse reactions were noted. CONCLUSION OMA is a CNS penetrant drug that reaches the brain tumor tissue in all tested concentrations. The inter-model variation in accumulation of OMA is associated to the extent of BBB disruption of each PDX model. Additional in vivo experiments are ongoing to investigate the therapeutic effect of OMA and longer exposure using in vivo models.

Costunolide and parthenolide: Novel blood-brain barrier permeable sesquiterpene lactones to improve barrier tightness

Sesquiterpene lactones - such as those found in chicory - are considered promising bioactive compounds. These small molecules have shown several health benefits for various diseases, including brain disorders. However, it is unknown whether these compounds can cross the blood-brain barrier (BBB), and which could be the effects on brain microvascular endothelial cells. We show that six sesquiterpene lactones evaluated in an in vitro model of the BBB have different capacities to be transported through the barrier. Costunolide presented more than 20 % of transport while lactucin, 11β-13-dihydrolactucin, 11β-13-dihydrolactucopicrin, and parthenolide presented between 10 % and 20 %, whilst almost no transport was detected for lactucopicrin. Furthermore, costunolide and parthenolide reduced P-gp ABC transporter expression alongside an increase in caveolin-1, the main protein of caveolae. Remarkably, these two compounds improved barrier tightness by increasing the expression of both tight and adherens junctions. These findings open a new avenue to explore costunolide and parthenolide as promising compounds for brain therapies.

Zinc Oxide Nanoparticles and Cancer Chemotherapy: Helpful Tools for Enhancing Chemo-sensitivity and Reducing Side Effects?

Cancer chemotherapy is still a serious challenge. Chemo-resistance and destructive side effects of chemotherapy drugs are the most critical limitations of chemotherapy. Chemo-resistance is the leading cause of chemotherapy failure. Chemo-resistance, which refers to the resistance of cancer cells to the anticancer effects of chemotherapy drugs, is caused by various reasons. Among the most important of these reasons is the increase in the efflux of chemotherapy drugs due to the rise in the expression and activity of ABC transporters, the weakening of apoptosis, and the strengthening of stemness. In the last decade, a significant number of studies focused on the application of nanotechnology in cancer treatment. Considering the anti-cancer properties of zinc, zinc oxide nanoparticles have received much attention in recent years. Some studies have indicated that zinc oxide nanoparticles can target the critical mechanisms of cancer chemo-resistance and enhance the effectiveness of chemotherapy drugs. These studies have shown that zinc oxide nanoparticles can reduce the activity of ABC transporters, increase DNA damage and apoptosis, and attenuate stemness in cancer cells, leading to enhanced chemo-sensitivity. Some other studies have also shown that zinc oxide nanoparticles in low doses can be helpful in minimizing the harmful side effects of chemotherapy drugs. In this article, after a brief overview of the mechanisms of chemo-resistance and anticancer effects of zinc, we will review all these studies in detail.

Regulation of the ATP-binding cassette transporters ABCB1, ABCG2 and ABCC5 by nuclear receptors in porcine blood-brain barrier endothelial cells.

Blood-brain barrier (BBB) ABCB1, ABCG2 and ABCC5 transporters influence central therapeutic drug distribution. Transporter expression is regulated by the NR3C1, NR1I3 and NR1I2 nuclear receptors, but their precise roles in brain are poorly understood. We investigated the effects of selective ligand-based activation of NR3C1, NR1I3, NR1I2 and NR2B1 in porcine brain endothelial cells (PBECs). Primary cultures of PBECs were exposed to NR3C1, NR1I3 and NR1I2 ligands and ABCB1, ABCG2 and ABCC5 transporter activities determined by measuring intracellular accumulation of fluorescent probes. Western blotting was used to determine the effects of receptor ligands on expression of ABCB1, ABCG2, ABCC5, NR1I2, NR1I3, NR3C1 and NR2B1. Fluorescent immunocytochemistry was employed to assess the effects of receptor ligands on the cellular localisation of NR1I2 and NR1I3. The NR1I2 agonist rifampicin significantly up-regulated ABCG2 activity, which is counteracted by co-treatment with NR1I2 antagonist l-sulforaphane. The NR1I3 agonist 6-(4-chlorophenyl)-imidazo[2,1-b]thiazole-5-carbaldehyde and inverse agonist meclizine significantly down-regulated ABCB1, ABCG2 and ABCC5 activity. NR3C1 agonist dexamethasone significantly increased ABCB1, ABCG2 and ABCC5 activity and ABCG2 and ABCC5 protein expression, which was counteracted by co-treatment with the NR3C1 antagonist mifepristone. This first study demonstrates that NR1I3 and NR3C1 regulate ABCC5 activity and protein expression in BBB endothelial cells. In PBECs, expression of key ATP-binding cassette (ABC) transporters and nuclear receptors is differentially regulated by NR1I3, NR1I2, NR3C1 and NR2B1. This will help to better understand the response of the BBB to physiological and pharmacological activation of nuclear receptors.

Altered Gene Expression of Cytochrome P450 and ABC Transporter in Human Hepatocellular Carcinoma HepG2 Cells Exposed to Bardoxolone Methyl.

Bardoxolone methyl (BX) is expected to be an innovate therapeutic agent for chronic kidney disease (CKD). The aim of the present study was to examine whether the expression of subtypes of cytochrome P450 (CYP) and ABC transporters was altered in human hepatocellular carcinoma HepG2 cells by exposure to BX. The expression of mRNAs for CYP1A2, CYP2E1, P-glycoprotein, multidrug resistance-associated protein 1-3, and breast cancer resistance protein was significantly increased by exposure of HepG2 cells to BX, while the expression of CYP3A4 mRNA was significantly decreased under the same conditions. BX had no significant effect on the expression of mRNAs for CYP2C9 and CYP2C19 in HepG2 cells. In conclusion, this study demonstrated that the gene expression of several CYPs and ABC transporters in HepG2 cells was altered when exposed to BX, suggesting the need to pay careful attention to drug-drug interactions in patients receiving BX for CKD treatment.