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International Journal of Molecular... Jun 2023Multidrug resistance (MDR) is a common phenomenon in clinical oncology, whereby cancer cells become resistant to chemotherapeutic drugs A common MDR mechanism is the...
Multidrug resistance (MDR) is a common phenomenon in clinical oncology, whereby cancer cells become resistant to chemotherapeutic drugs A common MDR mechanism is the overexpression of ATP-binding cassette efflux transporters in cancer cells, with P-glycoprotein (P-gp) being one of them. New 3,4-seco-lupane triterpenoids, and the products of their intramolecular cyclization with the removed 4,4-gem-dimethyl group, were synthesized by the selective transformations of the A-ring of dihydrobetulin. Among the semi-synthetic derivatives, the MT-assay-enabled methyl ketone (), exhibiting the highest cytotoxicity (0.7-16.6 µM) against nine human cancer cell lines, including P-gp overexpressing subclone HBL-100/Dox, is identified. In silico, has been classified as a potential P-gp-inhibitor; however, the Rhodamine 123 efflux test, and the combined use of P-gp-inhibitor verapamil with in vitro, showed the latter to be neither an inhibitor nor a substrate of P-gp. As the studies have shown, the cytotoxic effect of against HBL-100/Dox cells is, arguably, induced through the activation of the ROS-mediated mitochondrial pathway, as evidenced by the positive Annexin V-FITC staining of apoptotic cells, the cell cycle arrest in the G0/G1 phase, mitochondrial dysfunction, cytochrome release, and the activation of caspase-9 and -3.
Topics: Humans; Doxorubicin; Drug Resistance, Neoplasm; Antineoplastic Agents; Drug Resistance, Multiple; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily B; ATP-Binding Cassette Transporters; Cell Line, Tumor
PubMed: 37373011
DOI: 10.3390/ijms24129863 -
European Journal of Nuclear Medicine... Dec 2021P-glycoprotein (P-gp) function is altered in several brain disorders; thus, it is of interest to monitor the P-gp function in vivo using PET. (R)-[C]verapamil is...
PURPOSE
P-glycoprotein (P-gp) function is altered in several brain disorders; thus, it is of interest to monitor the P-gp function in vivo using PET. (R)-[C]verapamil is considered the gold standard tracer to measure the P-gp function; however, it presents some drawbacks that limit its use. New P-gp tracers have been developed with improved properties, such as [F]MC225. This study compares the characteristics of (R)-[C]verapamil and [F]MC225 in the same subjects.
METHODS
Three non-human primates underwent 4 PET scans: 2 with (R)-[C]verapamil and 2 with [F]MC225, at baseline and after P-gp inhibition. The 30-min PET data were analyzed using 1-Tissue Compartment Model (1-TCM) and metabolite-corrected plasma as input function. Tracer kinetic parameters at baseline and after inhibition were compared. Regional differences and simplified methods to quantify the P-gp function were also assessed.
RESULTS
At baseline, [F]MC225 V values were higher, and k values were lower than those of (R)-[C]verapamil, whereas K values were not significantly different. After inhibition, V values of the 2 tracers were similar; however, (R)-[C]verapamil K and k values were higher than those of [F]MC225. Significant regional differences between tracers were found at baseline, which disappeared after inhibition. The positive slope of the SUV-TAC was positively correlated to the K and V of both tracers.
CONCLUSION
[F]MC225 and (R)-[C]verapamil show comparable sensitivity to measure the P-gp function in non-human primates. Moreover, this study highlights the 30-min V as the best parameter to measure decreases in the P-gp function with both tracers. [F]MC225 may become the first radiofluorinated tracer able to measure decreases and increases in the P-gp function due to its higher baseline V.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Animals; Blood-Brain Barrier; Brain; Carbon Radioisotopes; Positron-Emission Tomography; Primates; Verapamil
PubMed: 34117508
DOI: 10.1007/s00259-021-05411-2 -
International Journal For Parasitology.... Dec 2021P-glycoproteins from the ATP-binding cassette transporter family are responsible for drug evasion by bacterial pathogens and neoplastic cells. More recently, these...
P-glycoproteins from the ATP-binding cassette transporter family are responsible for drug evasion by bacterial pathogens and neoplastic cells. More recently, these multidrug resistance transporters have been investigated for contributions to drug resistance in nematode parasites. In this study, we cloned and characterized the P-glycoprotein Tca-Pgp-11.1 from Toxocara canis, the canine intestinal ascarid. Large numbers of Tca-Pgp-11 transcripts were observed in the intestine of adult male and female worms. Heterologous expression studies confirmed sensitivity to known P-glycoprotein inhibitors. Interestingly, the competitive inhibitor verapamil had lower IC values than newer generation inhibitors that are designed to allosterically modulate mammalian P-glycoprotein. Consistent with other nematode P-glycoproteins, Tca-Pgp-11.1 was sensitive to ivermectin and selamectin but not moxidectin. Taken together, our data suggests that T. canis P-glycoproteins represent nematode-specific drug targets that could be exploited to enhance efficacy of existing anthelmintics.
Topics: ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Animals; Anthelmintics; Dogs; Female; Male; Pharmaceutical Preparations; Toxocara canis
PubMed: 34753107
DOI: 10.1016/j.ijpddr.2021.10.002 -
Zhong Nan Da Xue Xue Bao. Yi Xue Ban =... Dec 2022Fluorouracil chemotherapeutic drugs are the classic treatment drugs of gastric cancer. But the problem of drug resistance severely limits their clinical application....
OBJECTIVES
Fluorouracil chemotherapeutic drugs are the classic treatment drugs of gastric cancer. But the problem of drug resistance severely limits their clinical application. This study aims to investigate whether hypoxia microenvironment affects gastric cancer resistance to 5-fluorouracil (5-FU) and discuss the changes of gene and proteins directly related to drug resistance under hypoxia condition.
METHODS
Gastric cancer cells were treated with 5-FU in hypoxia/normoxic environment, and were divided into a Normoxic+5-FU group and a Hypoxia+5-FU group. The apoptosis assay was conducted by flow cytometry Annexin V/PI double staining. The real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were used to detect the expression level of hypoxia inducible factor-1α (HIF-1α), multidrug resistance (MDR1) gene, P-glycoprotein (P-gp), and vascular endothelial growth factor (VEGF) which were related to 5-FU drug-resistance. We analyzed the effect of hypoxia on the treatment of gastric cancer with 5-FU.
RESULTS
Compared with the Normoxic+5-FU group, the apoptosis of gastric cancer cells treated with 5-FU in the Hypoxia+5-FU group was significantly reduced (P<0.05), and the expression of apoptosis promoter protein caspase 8 was also decreased. Compared with the the Normoxic+5-FU group, HIF-1α mRNA expression in the Hypoxia+5-FU group was significantly increased (P<0.05), and the mRNA and protein expression levels of MDR1, P-gp and VEGF were also significantly increased (all P<0.05). The increased expression of MDR1, P-gp and VEGF had the same trend with the expression of HIF-1α.
CONCLUSIONS
Hypoxia is a direct influencing factor in gastric cancer resistance to 5-FU chemotherapy. Improvement of the local hypoxia microenvironment of gastric cancer may be a new idea for overcoming the resistance to 5-FU in gastric cancer.
Topics: Humans; Fluorouracil; Vascular Endothelial Growth Factor A; Stomach Neoplasms; Drug Resistance, Multiple; Vascular Endothelial Growth Factors; Hypoxia; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Cell Line, Tumor; Cell Hypoxia; RNA, Messenger; Hypoxia-Inducible Factor 1, alpha Subunit; Tumor Microenvironment
PubMed: 36748372
DOI: 10.11817/j.issn.1672-7347.2022.210560 -
Cancer Drug Resistance (Alhambra,... 2019P-glycoprotein (P-gp or ABCB1) is a member of the broad family of ABC transporters. P-gp participates in the establishment of physiological barriers limiting cellular... (Review)
Review
P-glycoprotein (P-gp or ABCB1) is a member of the broad family of ABC transporters. P-gp participates in the establishment of physiological barriers limiting cellular access of a large number of toxic compounds. It thus plays important roles in the pharmacokinetics of these compounds. Cancer cells and cells infected by viruses exploit the presence of P-gp to fend off drug treatment, rendering them multidrug-resistant. Overcoming multidrug resistance caused by expression of ABC transporters has gained increasing attention in the field of drug development. Recently, studies of P-gp, especially from structural investigations by both cryo-electron microscopy and X-ray crystallography, have provided high-resolution mechanistic details for the function of this transporter. Structures with increasing resolution and accuracy in various substrate- and inhibitor-bound forms are available for analysis and a consensus on the mechanism of substrate polyspecificity is emerging. The use of new structural information may aid development of P-gp inhibitors as well as compounds that may bypass P-gp action.
PubMed: 35582581
DOI: 10.20517/cdr.2019.22 -
International Journal of Molecular... Mar 2023The drug efflux transporter permeability glycoprotein (P-gp) plays an important role in oral drug absorption and distribution. Under microgravity (MG), the changes in...
The drug efflux transporter permeability glycoprotein (P-gp) plays an important role in oral drug absorption and distribution. Under microgravity (MG), the changes in P-gp efflux function may alter the efficacy of oral drugs or lead to unexpected effects. Oral drugs are currently used to protect and treat multisystem physiological damage caused by MG; whether P-gp efflux function changes under MG remains unclear. This study aimed to investigate the alteration of P-gp efflux function, expression, and potential signaling pathway in rats and cells under different simulated MG (SMG) duration. The altered P-gp efflux function was verified by the in vivo intestinal perfusion and the brain distribution of P-gp substrate drugs. Results showed that the efflux function of P-gp was inhibited in the 7 and 21 day SMG-treated rat intestine and brain and 72 h SMG-treated human colon adenocarcinoma cells and human cerebral microvascular endothelial cells. P-gp protein and gene expression levels were continually down-regulated in rat intestine and up-regulated in rat brain by SMG. P-gp expression was regulated by the Wnt/β-catenin signaling pathway under SMG, verified by a pathway-specific agonist and inhibitor. The elevated intestinal absorption and brain distribution of acetaminophen levels also confirmed the inhibited P-gp efflux function in rat intestine and brain under SMG. This study revealed that SMG alters the efflux function of P-gp and regulates the Wnt/β-catenin signaling pathway in the intestine and the brain. These findings may be helpful in guiding the use of P-gp substrate drugs during spaceflight.
Topics: Rats; Humans; Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Wnt Signaling Pathway; Weightlessness; Endothelial Cells; Adenocarcinoma; Colonic Neoplasms; Intestines; Brain
PubMed: 36982513
DOI: 10.3390/ijms24065438 -
Journal of Hypertension Nov 2019P-glycoprotein (P-gp), the product of the ABCB1 gene, is involved in the transport of aldosterone and cortisol in adrenal cells in vitro but its physiological role in...
OBJECTIVES
P-glycoprotein (P-gp), the product of the ABCB1 gene, is involved in the transport of aldosterone and cortisol in adrenal cells in vitro but its physiological role in humans remains controversial. Our objective was to test the influence of P-gp polymorphisms on aldosterone.
METHODS
We evaluated plasma aldosterone concentration (PAC), urinary aldosterone, and blood pressure in a cohort of white normotensive men at baseline on diets unrestricted for sodium and potassium and after a 5-day treatment with 500 mg b.i.d. clarithromycin, a P-gp inhibitor. Included were 20 homozygous wild-type (P-gp0), 20 heterozygous (P-gp1), and 20 individuals with combined 2677G>T/A-3435C>T loss-of-function polymorphism of the ABCB1 gene (P-gp2).
RESULTS
At baseline, PAC, urinary aldosterone, urinary free cortisol to urine creatinine ratios, and blood pressure did not differ in the three genotypes. After clarithromycin administration, the urinary aldosterone to creatinine ratio increased by an average of 30% in the entire cohort (P < 0.001, n = 60). Increases were pronounced in P-gp1 (+40%; P = 0.014) and P-gp2 individuals (+50%; P = 0.020) but lesser and were NS in P-gp0 individuals (+10%; P = 0.259). PAC also increased from baseline after clarithromycin treatment in all individuals (+19%, P = 0.050); however, the increase in PAC was NS when the three genotypes were analyzed separately.
CONCLUSION
In our experimental conditions, the interaction between P-gp inhibition and the ABCB1 genotype, suggests that aldosterone is indeed a physiological endogenous substrate of P-gp in humans and that P-gp interferes with the net equilibrium between aldosterone secretion and elimination processes in humans.Clinical Trial Registration - URL: http://www.clinicaltrials.gov. Unique identifier: NCT01627665.
Topics: ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Adult; Aldosterone; Clarithromycin; Genotype; Healthy Volunteers; Heterozygote; Homozygote; Humans; Hydrocortisone; Male; Polymorphism, Single Nucleotide; Potassium; Renin; Sodium; Young Adult
PubMed: 31157746
DOI: 10.1097/HJH.0000000000002150 -
Scientific Reports Aug 2020P-glycoproteins (Pgp) have been proposed as contributors to the widespread macrocyclic lactone (ML) resistance in several nematode species including a major pathogen of...
P-glycoproteins (Pgp) have been proposed as contributors to the widespread macrocyclic lactone (ML) resistance in several nematode species including a major pathogen of foals, Parascaris univalens. Using new and available RNA-seq data, ten different genomic loci encoding Pgps were identified and characterized by transcriptome-guided RT-PCRs and Sanger sequencing. Phylogenetic analysis revealed an ascarid-specific Pgp lineage, Pgp-18, as well as two paralogues of Pgp-11 and Pgp-16. Comparative gene expression analyses in P. univalens and Caenorhabditis elegans show that the intestine is the major site of expression but individual gene expression patterns were not conserved between the two nematodes. In P. univalens, PunPgp-9, PunPgp-11.1 and PunPgp-16.2 consistently exhibited the highest expression level in two independent transcriptome data sets. Using RNA-Seq, no significant upregulation of any Pgp was detected following in vitro incubation of adult P. univalens with ivermectin suggesting that drug-induced upregulation is not the mechanism of Pgp-mediated ML resistance. Expression and functional analyses of PunPgp-2 and PunPgp-9 in Saccharomyces cerevisiae provide evidence for an interaction with ketoconazole and ivermectin, but not thiabendazole. Overall, this study established reliable reference gene models with significantly improved annotation for the P. univalens Pgp repertoire and provides a foundation for a better understanding of Pgp-mediated anthelmintic resistance.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Animals; Antiparasitic Agents; Ascaridida Infections; Ascaridoidea; Drug Resistance; Helminth Proteins; Horses; Ivermectin; Phylogeny; Reverse Transcriptase Polymerase Chain Reaction; Sequence Analysis, DNA; Sequence Analysis, RNA; Transcriptome
PubMed: 32788636
DOI: 10.1038/s41598-020-70529-6 -
Molecules (Basel, Switzerland) Oct 2022The activity of the P-glycoprotein (P-gp) transporter encoded by the ABCB1 gene confers resistance to anticancer drugs and contributes to cancer-related mortality and...
The activity of the P-glycoprotein (P-gp) transporter encoded by the ABCB1 gene confers resistance to anticancer drugs and contributes to cancer-related mortality and morbidity. Recent studies revealed the cytotoxic effects of the endogenous dipeptide carnosine. The current study aimed to investigate the role of carnosine as a potential inhibitor of P-gp activity. We used molecular docking and molecular dynamic simulations to study the possible binding and stability of carnosine-P-gp interactions compared with verapamil. In vitro assays using doxorubicin-resistant NCI/ADR-RES cells were established to test the effects of carnosine (10-300 µM) on P-gp activity by the rhodamine-123 efflux assay and its effect on cell viability and doxorubicin-induced cytotoxicity. Verapamil (10 µM) was used as a positive control. The results showed that carnosine binding depends mainly on hydrogen bonding with GLU875, GLN946, and ALA871, with a higher average Hbond than verapamil. Carnosine showed significant but weaker than verapamil-induced rhodamine-123 accumulation. Carnosine and verapamil similarly inhibited cell viability. However, verapamil showed a more significant potentiating effect on doxorubicin-induced cytotoxicity than a weaker effect of carnosine at 300 µM. These results suggest that carnosine inhibits P-gp activity and potentiates doxorubicin-induced cytotoxicity at higher concentrations. Carnosine might be a helpful lead compound in the fight against multidrug-resistant cancers.
Topics: Drug Resistance, Multiple; Carnosine; ATP Binding Cassette Transporter, Subfamily B, Member 1; Molecular Docking Simulation; Drug Resistance, Neoplasm; Doxorubicin; Rhodamine 123; Verapamil; ATP Binding Cassette Transporter, Subfamily B; Antineoplastic Agents
PubMed: 36364209
DOI: 10.3390/molecules27217383 -
Cancer Medicine May 2023Multidrug resistance (MDR) is a primary limitation of breast cancer chemotherapy. The common mechanism of MDR is various anticancer drugs can be effluxed by the cell...
Multidrug resistance (MDR) is a primary limitation of breast cancer chemotherapy. The common mechanism of MDR is various anticancer drugs can be effluxed by the cell membrane protein P-glycoprotein (P-gp). Here, we found that ectopic overexpression of Shc3 was detected specifically in drug-resistant breast cancer cells, consequently reducing sensitivity to chemotherapy and promoting cell migration by mediating P-gp expression. However, the molecular mechanism underlying the interplay between P-gp and Shc3 in breast cancer is unknown. We reported an additional resistance mechanism involving an increase in the active form of P-gp after Shc3 upregulation. MCF-7/ADR and SK-BR-3 cells can be sensitive to doxorubicin after knockdown of Shc3. Our results indicated that the interaction between ErbB2 and EphA2 is indirect and regulated by Shc3, and also, this complex is essential for activation of the MAPK and AKT pathways. Meanwhile, Shc3 promotes ErbB2 nuclear translocation, followed by a subsequent increase of the COX2 expression through ErbB2 binding to the COX2 promoter. We further demonstrated that COX2 expression was positively correlated with P-gp expression and the Shc3/ErbB2/COX2 axis upregulates P-gp activity in vivo. Our results show the crucial roles of Shc3 and ErbB2 in modulating P-gp efficacy in breast cancer cells and suggest that Shc3 inhibition may enhance the sensitivity to chemotherapeutic drugs that target oncogene addiction pathways.
Topics: Humans; Female; Breast Neoplasms; Cyclooxygenase 2; ATP Binding Cassette Transporter, Subfamily B, Member 1; Antineoplastic Agents; Doxorubicin; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Cell Line, Tumor; Src Homology 2 Domain-Containing, Transforming Protein 3; Receptor, ErbB-2
PubMed: 36880347
DOI: 10.1002/cam4.5768