Search Results (656)

Growth hormone (GH) signaling has been implicated in tumor progression and therapy resistance across multiple cancer types, yet its role in bladder cancer remains largely unexplored. In this study, we investigated the impact of GH and its receptor (GHR) on therapy resistance and disease progression in urothelial carcinoma (UC) through integrated transcriptomic and in vitro analyses. Transcriptomic profiling of The Cancer Genome Atlas bladder cancer cohort revealed that high tumoral GHR expression was associated with differential upregulation of genes involved in drug efflux, epithelial-to-mesenchymal transition (EMT), and extracellular matrix (ECM) remodeling. Notably, elevated GHR levels correlated with significantly reduced overall survival in patients with UC. In parallel, in vitro experiments demonstrated that GH promotes chemoresistance in UC cell lines via upregulation of ATP-binding cassette-containing (ABC) transporters and activation of EMT. GH also modulated ECM-remodeling-associated genes in a chemotherapy-dependent manner, including matrix metalloproteinases and tissue inhibitors of metalloproteinases. Importantly, these effects were abrogated by Pegvisomant, a GHR antagonist, indicating the functional relevance of GH/GHR signaling in the mediation of these phenotypes. Collectively, our findings support a mechanistic role for GH signaling in driving therapy resistance and tumor aggressiveness in bladder cancer and suggest GHR antagonism as a potential therapeutic strategy to improve treatment outcomes. Full article

Background/Objectives: P-glycoprotein (P-gp), an ATP-binding cassette (ABC) transporter, plays a key role in multidrug resistance by actively exporting chemotherapeutic agents and xenobiotics from cells. Overexpression of P-gp significantly reduces intracellular drug accumulation and compromises treatment efficacy. Despite extensive research, clinically approved P-gp inhibitors remain elusive due to toxicity, poor specificity, and limited efficacy. This study investigates DMH1, a selective type I BMP receptor inhibitor, as a novel P-gp inhibitor. Methods: DMH1 cytotoxicity was assessed in P-gp-overexpressing (PC3-TxR, K562/Dox) and P-gp-deficient (PC3) cell lines using MTT assays. P-gp inhibition was evaluated using calcein AM retention and daunorubicin (DNR) accumulation assays. Kinetic analysis determined DMH1’s effect on P-gp-mediated transport (Vmax and Km). ATPase activity assays were performed to assess DMH1’s impact on ATP hydrolysis. Preliminary molecular docking (CB-Dock2) was used to predict DMH1’s binding site on the human P-gp structure (PDB ID: 6QEX). Results: DMH1 showed no cytotoxicity in P-gp-overexpressing or deficient cells. It significantly enhanced intracellular accumulation of Calcein AM and DNR, indicating effective inhibition of P-gp function. Kinetic data revealed that DMH1 reduced Vmax without affecting Km, consistent with noncompetitive, allosteric inhibition. DMH1 also inhibited ATPase activity in a dose-dependent manner. Docking analysis suggested DMH1 may bind to an allosteric site in the transmembrane domain, potentially stabilizing the inward-facing conformation. Conclusions: DMH1 is a promising noncompetitive, allosteric P-gp inhibitor that enhances intracellular drug retention without cytotoxicity, supporting its potential as a lead compound to overcome multidrug resistance and improve chemotherapeutic efficacy. Full article

Forensic entomotoxicology is a subdiscipline that utilizes necrophagous insects as bioindicators for detecting drugs and toxicants in decomposed remains, particularly in cases where conventional biological matrices are no longer available. Toxic substances can profoundly alter insect development, physiology, and community succession, potentially impacting the accuracy of postmortem interval (PMI) estimation. This review systematically summarizes the effects of various xenobiotics, including pesticides, illicit drugs, sedatives, heavy metals, and antibiotics on larval growth, physiological traits, and gut microbial composition in forensically relevant flies. However, most studies to date have relied primarily on phenotypic observations, with limited insight into underlying molecular mechanisms. Significant interspecies and dose-dependent variability also exists in the absorption, metabolism, and physiological responses to xenobiotics. We highlight recent advances in multi-omics technologies that facilitate the identification of molecular biomarkers associated with xenobiotic exposure, particularly within the insect detoxification system. Key components such as cytochrome P450 monooxygenases (P450s), glutathione S-transferases (GSTs), and ATP-binding cassette (ABC) transporters play essential roles in xenobiotic metabolism and insecticide resistance. Additionally, the insect fat body serves as a central hub for detoxification, hormonal regulation, and energy metabolism. It integrates signals related to xenobiotic exposure and modulates larval development, making it a promising model for future mechanistic studies in insect toxicology. Altogether, this review offers a comprehensive and reliable framework for understanding the complex interactions between toxic substance exposure, insect ecology, and decomposition in forensic investigations. Full article

Familial hypercholesterolemia (FH) is a genetic disorder marked by significantly elevated levels of low-density lipoprotein cholesterol (LDL-C) since childhood, substantially increasing the risk of premature atherosclerosis and cardiovascular disease. While dysfunction of hepatic LDL-C receptors is the main underlying cause, the gastrointestinal tract plays a key role in cholesterol homeostasis and represents an important therapeutic target. Inhibition of intestinal cholesterol absorption has emerged as an effective strategy in the management of pediatric FH, particularly in patients for whom statins may not be the ideal first-line treatment. Ezetimibe, an inhibitor of the Niemann-Pick C1-like 1 (NPC1L1) protein, has been shown to reduce LDL-C levels in children with FH, with a greater efficacy observed when used in combination with statins. Bile acid sequestrants also enhance cholesterol excretion but are often limited by gastrointestinal side effects, while dietary interventions, such as phytosterol supplementation and fiber-enriched diets, provide additional benefits in lowering LDL-C and are generally well tolerated. Emerging therapies, including microbiota-targeted strategies and novel cholesterol absorption inhibitors, show promise for expanding future treatment options. This review explores the mechanisms of intestinal cholesterol absorption and their relevance to pediatric FH. We examine key pathways, including dietary cholesterol uptake through NPC1L1, bile acid reabsorption, and cholesterol efflux mediated by ATP-binding cassette transporters, while also discussing clinical and experimental evidence on pharmacological and dietary interventions that modulate these pathways. A deeper understanding of cholesterol metabolism, the emerging role of the gut microbiota, and innovative therapeutic agents can support the development of more effective and personalized approaches to the treatment of children with FH. Full article

Bombyx mori, a key lepidopteran model with economic importance, is highly susceptible to environmental heavy metal pollution. This study investigated the mechanisms of Pb toxicity and the associated detoxification and metabolic defense responses in silkworms, employing transcriptome sequencing, enzyme activity assays, and histopathological analysis. Pb exposure caused significant histopathological changes and apoptosis in the fat body, marked by structural disorganization, swollen adipocytes, and degraded extracellular matrix. Molecular analysis showed activation of antioxidant defenses, with superoxide dismutase (SOD) and catalase (CAT) activities significantly elevated (p < 0.05), while peroxidase (POD) activity declined (p < 0.05). Levels of malondialdehyde (MDA) and glutathione (GSH) also decreased. In detoxification responses, carboxylesterase (CarE) activity was reduced, whereas cytochrome P450 (P450) and glutathione S-transferase (GST) activities increased (p < 0.05). Transcriptome sequencing revealed 1,418 differentially expressed genes (DEGs), with notable upregulation of key detoxification genes (p < 0.05), including six cytochrome P450s (CYPs), five uridine diphosphate-glycosyltransferases (UGTs), three glutathione S-transferases (GSTs), and six ATP-binding cassette transporters (ABCs). KEGG enrichment analysis highlighted the involvement of these DEGs in drug metabolism, glutathione metabolism, and ABC transporter pathways (p < 0.05). Functional validation showed that knocking down Cap ‘n’ Collar C (CncC) significantly suppressed key detoxification genes (CYP18A1, CYP332A1, GSTd3, GSTt1, UGT33D8; p < 0.05). qRT-PCR and Western blot analyses confirmed that the Caspase-3 pathway mediates Pb-induced apoptosis, with increased cleaved Caspase-3 and Caspase-4 levels following CncC silencing. Overall, our findings elucidate the mechanisms of Pb toxicity in silkworms and identify CncC as a critical regulator of detoxification and defense against heavy metal stress in lepidopteran insects. Full article

Anthracyclines have been clinically well established in cancer chemotherapy for decades. The main limitations of this drug class are the development of resistance and severe side effects. In the present investigation, we analyzed 30 anthracyclines in a panel of 59 cell lines of the National Cancer Institute, USA. The log₁₀IC₅₀ values varied from −10.49 M (3′-deamino-3′-(4″-(3″-cyano)morpholinyl)-doxorubicin, 1) to −4.93 M (N,N-dibenzyldaunorubicin hydrochloride, 30). Multidrug-resistant NCI-ADR-Res ovarian cancer cells revealed a high degree of resistance to established anthracyclines (between 18-fold to idarubicin (4) and 166-fold to doxorubicin (13) compared to parental, drug-sensitive OVCAR8 cells). The resistant cells displayed only low degrees of resistance (1- to 5-fold) to four other anthracyclines (7, 18, 28, 30) and were even hypersensitive (collaterally sensitive) to two compounds (1, 26). Live cell time-lapse microscopy proved the cross-resistance of the three chosen anthracyclines (4, 7, 9) on sensitive CCRF/CEM and multidrug-resistant CEM/ADR5000 cells. Structure–activity relationships showed that the presence of tertiary amino functions is helpful in avoiding resistance, while primary amines rather increased resistance development. An α-aminonitrile function as in compound 1 was favorable. Investigating the mRNA expression of 49 ATP-binding cassette (ABC) transporter genes showed that ABCB1/MDR1 encoding P-glycoprotein was the most important one for acquired and inherent resistance to anthracyclines. Molecular docking demonstrated that all anthracyclines bound to the same binding domain at the inner efflux channel side of P-glycoprotein with high binding affinities. Kaplan–Meier statistics of RNA sequencing data of more than 8000 tumor biopsies of TCGA database revealed that out of 23 tumor entities high ABCB1 expression was significantly correlated with worse survival times for acute myeloid leukemia, multiple myeloma, and hepatocellular carcinoma patients. This indicates that ABCB1 may serve as a prognostic marker in anthracycline-based chemotherapy regimens in these tumor types and a target for the development of novel anthracycline derivatives. Full article

The present work reports the synthesis and structural design of three novel Zn(II) complexes [Zn(L¹)(CH₃COO)(H₂O)] (1), [Zn(L²)₂] (2), and [Zn(L³)₂] (3) with carbazate ligands, 2-acetylpyridine-methylcarbazate (HL¹), 2-acetylpyridine-ethylcarbazate (HL²), and 2-acetylpyridine-benzylcarbazate (HL³). All compounds were characterized by spectroscopic methods, and the crystal structures of the complexes were elucidated by single-crystal X-ray. Based on the analysis, distorted square pyramid geometry is suggested for complex (1) and an octahedral geometry is suggested for complexes (2) and (3) with the ligands exhibiting an NNO-donor system. The 3D Hirshfeld surface and the 2D fingerprint plot were used to study the non-covalent interactions in the crystal structures. The in vitro antibacterial investigation of the free ligands and their complexes was performed against different strains of periodontopathogen bacteria. The Zn(II) complexes showed more potent antibacterial activity than the free ligand. Molecular docking studies showed the metal complexes as promising candidates for further therapeutic exploration, particularly in targeting the ATP-binding cassette transporter with peptidase domain of the cariogenic bacteria S. mutans (PDB code 5XE9) and the prolyl tripeptidyl aminopeptidase from P. gingivalis anaerobic bacteria (PDB code 2EEP) inhibition. Full article

Tan sheep outperform Dorper sheep in meat-quality traits, including muscle fiber characteristics and fatty acid composition, while Dorper sheep excel in carcass weight. However, the molecular mechanisms underlying these breed-specific traits, especially gut microbiota–bile acid (BA) interactions, remain poorly understood. As host–microbiota co-metabolites, BAs are converted by colonic microbiota via bile salt hydrolase (BSH) and dehydroxylases into secondary BAs, which activate BA receptors to regulate host lipid and glucose metabolism. This study analyzed colonic BA profiles in 8-month-old Tan and Dorper sheep, integrating microbiome and longissimus dorsi muscle transcriptome data to investigate the gut–muscle axis in meat-quality and carcass trait regulation. Results showed that Tan sheep had 1.6-fold higher secondary BA deoxycholic acid (DHCA) levels than Dorper sheep (p < 0.05), whereas Dorper sheep accumulated conjugated primary BAs glycocholic acid (GCA) and tauro-α-muricholic acid (p < 0.05). Tan sheep exhibited downregulated hepatic BA synthesis genes, including cholesterol 7α-hydroxylase (CYP7A1) and 27-hydroxylase (CYP27A1), alongside upregulated transport genes such as bile salt export pump (BSEP), sodium taurocholate cotransporting polypeptide (NTCP), and ATP-binding cassette subfamily B member 4 (ABCB4), with elevated gut BSH activity (p < 0.05). DHCA was strongly correlated with g_Ruminococcaceae_UCG-014, ENSOARG00000001393, and ENSOARG00000016726, muscle fiber density, diameter, and linoleic acid (C18:2n6t) (|r| > 0.5, p < 0.05). In contrast, GCA was significantly associated with g_Lachnoclostridium_10, g_Rikenellaceae_RC9_gut_group, ENSOARG0000001232, carcass weight, and net meat weight (|r| > 0.5, p < 0.05). In conclusion, breed-specific colonic BA profiles were shaped by host–microbiota interactions, with DHCA potentially promoting meat quality in Tan sheep via regulation of muscle fiber development and fatty acid deposition, and GCA influencing carcass traits in Dorper sheep. This study provides novel insights into the gut microbiota–bile acid axis in modulating ruminant phenotypic traits. Full article

The development of resistance to standard cytostatics, such as 5-fluorouracil (5-FU), significantly limits the efficacy of colon cancer therapy, prompting the search for novel anticancer agents, particularly among natural compounds. This study evaluated the anticancer effects of isorhamnetin, a plant-derived flavonol, and its ability to modulate the expression of drug-resistance-related biomarkers in SW-480 and HT-29 colon cancer cells, with a focus on ATP-binding cassette (ABC) transporters. Isorhamnetin demonstrated strong cytotoxic and proapoptotic activity on both cell lines, while showing lower toxicity toward normal HaCaT cells. In addition to suppressing the mRNA expression of drug-metabolizing enzymes (CYP1A1 and CYP1B1), isorhamnetin significantly reduced the mRNA levels of multidrug resistance-associated proteins 1 and 5 (MRP1 and MRP5), as well as the P-glycoprotein (P-gp) level in SW-480 and HT-29 cells. Molecular docking analysis revealed a high binding affinity of isorhamnetin to CYP1A1, CYP1B1, P-gp, MRP1, MRP5, and glutathione S-transferase (GST) proteins, with stronger interactions than those observed for 5-FU, suggesting potential interference with their function. These results provide a solid basis for future investigations to confirm the therapeutic potential of isorhamnetin as a modulator of drug resistance in colon cancer cells. Full article

ABCG2 is a crucial ATP-binding cassette (ABC) transporter involved in multidrug resistance and essential physiological and pharmacological processes. In recent years, multiple ABCG2 structures have been resolved using cryo-electron microscopy (cryo-EM), providing significant insights into its conformational states during its transport cycle. However, even more than 25 years after its description, a high-resolution X-ray crystallographic structure is still unavailable, limiting the understanding of its dynamic transitions, as well as leaving aspects of the transport cycle unresolved and open to discussion. Given the complexity of ABCG2, a multidisciplinary approach is essential in order to fully elucidate its mechanism. This review compiles recent advances in ABCG2 structural biology, highlights unresolved controversies, and explores future directions to bridge the gap between structure and function. Moving forward, integrating multiple structural and functional approaches will be key to uncovering the intricate workings of this enigmatic transporter. In particular, detailed structural insights will be crucial to identifying new ABCG2 substrates and designing selective inhibitors, with important implications for therapeutic development. Full article

Background: Tariquidar (Tq) is an inhibitor of the multidrug resistance (MDR) proteins relevant to ATP-binding cassette transporters (ABC transporters), which suppresses the ATP-dependent efflux of a variety of hydrophilic and amphipathic compounds, including anticancer drugs. Tq is a representative of a new generation of MDR inhibitors with high affinity to ABC proteins. However, there are still no data on the possible effect of Tq on mitochondria as an important target in the regulation of cell death or survival. Methods: We investigated the influence of Tq on the Ca²⁺-dependent mitochondrial permeability transition pore (mPTP). The effect of Tq was assessed using several parameters, including the calcium load, membrane potential, and mitochondrial swelling. To evaluate the specific targets of Tq, selective inhibitors of components of the mitochondrial pore were used, including adenine nucleotides, carboxyatractylozide (Catr) and bongkrekic acid (BA), oligomycin, and cyclosporine A. Results: Tq decreased the calcium retention capacity, activated mitochondrial swelling, and lowered the influence of ADP and ATP, the inhibitors of the Ca²⁺-induced pore opening, at their low concentrations. These effects of Tq were observed in both calcium-load and swelling assays, thus mimicking the effect of Catr, a selective inhibitor of adenine nucleotide translocase (ANT). Tq also decreased the protective effect of BA, an inhibitor of ANT and mPTP, on the calcium retention capacity of mitochondria. Further, Tq dose-dependently decreased the inhibitory effect of a low ATP concentration but not of high concentrations, at which the effect of Tq was activated by oligomycin, an inhibitor of F-ATP synthase. Conclusions: The influence of Tq extends to mitochondria, specifically to the regulation of membrane permeability, promoting the activation of pore opening, probably through an interaction with ANT, a component of the pore-forming complex. The effect of Tq on the opening of mPTP is strongly dependent on the concentrations of adenine nucleotides and, consequently, on the functional state of mitochondria. The direct influence of Tq on mitochondria can be considered as a new activity that promotes the sensitization of cells to various treatments and stimuli. Full article

Chemotherapy resistance is a major obstacle in the treatment of ovarian cancer, often resulting in disease recurrence and poor prognosis for patients. A key contributor to this resistance is the overexpression of ATP-binding cassette (ABC) transporters, including breast cancer resistance protein (BCRP/ABCG2), which actively effluxes chemotherapeutic agents such as topotecan (TOP) or mitoxantrone (MIT), limiting their intracellular accumulation and efficacy. This study investigated the potential of elacridar (GG918), a potent dual P-gp and BCRP inhibitor, to overcome drug resistance in ovarian cancer cell lines. Both TOP-sensitive and TOP-resistant ovarian cancer cells were grown in two-dimensional (2D) monolayers and three-dimensional (3D) spheroid models to better mimic the tumor microenvironment. The expression of the ABCG2 gene was quantified via qPCR and BCRP protein levels were assessed by western blotting and immunofluorescence. Drug response was evaluated using MTT viability assays, while BCRP transporter activity was examined using flow cytometry and microscopic assessment of the intracellular retention of BCRP fluorescent substrates (Hoechst 33342 and MIT). In both 2D and 3D cultures, elacridar effectively inhibited BCRP function and significantly enhanced sensitivity to TOP. These findings suggest that elacridar can inhibit BCRP-mediated drug resistance in ovarian cancer cell models. Full article

Paraquat is one of the most widely used nonselective herbicides globally. Although the emergence of weed resistance to paraquat has progressed relatively slowly since the first reported case in Japan in 1980, it has been steadily increasing. Resistance in weedy plants is predominantly associated with non-target-site resistance (NTSR), particularly via reduced uptake and translocation to target sites (i.e., chloroplasts) and/or enhanced sequestration; increased antioxidant capacity is also a common mechanism by which plants cope with various stresses, including reactive oxygen species (ROS). However, direct evidence for paraquat transport mediated by membrane transporters in weeds has not been established. Over the past decade, research, especially in model plants such as Arabidopsis thaliana, has advanced our understanding of the mechanisms underlying plant resistance to paraquat. This brief review summarized recent studies on paraquat resistance, with a particular focus on uptake, translocation, and sequestration mechanisms. For instance, three L-amino acid transporter (LAT) proteins (LAT1/3/4) and one (PDR11) belonging to the PDR (pleiotropic drug resistance) subfamily within the ABC (ATP-binding cassette) transporter family were confirmed to exhibit paraquat transporter activity; furthermore, transporters such as DTX6 (detoxification efflux carrier) can export/sequestrate paraquat inside the cell to the vacuole and apoplast, which confers stronger paraquat resistance to nearly commercial doses. In addition, the evolving perspectives in paraquat resistance research integrating big data and artificial intelligence, development of paraquat-tolerant crops, and a proposal of ryegrass (Lolium. spp.) and/or goosegrass (Eleusine indica) as a model weed species for paraquat resistance studies were also briefly discussed. Further advances in elucidating the molecular mechanisms of paraquat resistance in plants, including weeds, are anticipated. Full article

Multidrug resistance (MDR) poses a significant challenge in cancer therapy, often leading to treatment failure and relapse. ATP-binding cassette (ABC) transporters, particularly ABCG2, play a pivotal role in MDR development by actively expelling chemotherapeutic agents from cancer cells. This study investigates the effects of two groups of primaquine derivatives—fumardiamides (1a–d) and bis-ureas (2a, b), both bearing halogenated benzene rings—on the activity of P-glycoprotein (P-gp) and ABCG2. Their potential to reverse MDR was evaluated through a series of functional assays aimed at comparing transporter–compound interactions. The results indicated that fumardiamide derivatives, specifically 1a, 1b, and 1d, exhibited potent inhibition of ABCG2 while having no effect on P-gp, demonstrating a selective mode of action. The tested derivatives displayed low to moderate cytotoxicity and did not affect ABCG2 expression or localization. Moreover, these compounds enhanced the sensitivity of drug-resistant cancer cell lines to mitoxantrone, underscoring their potential to overcome ABCG2-mediated MDR. These findings suggest that chemical modifications of primaquine, particularly the incorporation of fumardiamide moieties, confer novel biological properties, providing promising leads for the development of selective ABCG2 inhibitors. Full article

Progressive familial intrahepatic cholestasis type 2 (PFIC2) is a severe hepatocellular cholestasis due to biallelic variations in the ABCB11 (ATP-binding cassette B11) gene encoding the canalicular bile salt export pump (BSEP). Some missense variants identified in patients with PFIC2 do not traffic properly to the canalicular membrane. However, 4-phenybutyrate (4-PB) has been shown in vitro to partially correct the mis-trafficking of selected variants, resulting in an improvement of the medical conditions of corresponding PFIC2 patients. Herein, we report the ability of 4-PB analogous or homologous drugs and of non-4-PB related chemical correctors to rescue the canalicular expression and the activity of the folding-defective Abcb11^R1128C variant. New compounds, either identified by screening a chemical library or designed by structural homology with 4-PB (or its metabolites) and synthesized, were evaluated in vitro for their ability to (i) correct the canalicular localization of Abcb11^R1128C after transfection in hepatocellular polarized cell lines; (ii) restore the ³H-taurocholate transport of the Abcb11^R1128C protein in Madin–Darby canine kidney (MDCK) cells stably co-expressing Abcb11 and the sodium taurocholate co-transporting polypeptide (Ntcp/Slc10A1). Glycerol phenylbutyrate (GPB), phenylacetate (PA, the active metabolite of 4-PB), 3-hydroxy-2-methyl-4-phenylbutyrate (HMPB, a 4-PB metabolite analog chemically synthesized in our laboratory) and 4-oxo-1,2,3,4-tetrahydro-naphthalene-carboxylate (OTNC, from the chemical library screening) significantly increased the proportion of canalicular Abcb11^R1128C protein. GPB, PA, ursodeoxycholic acid (UDCA), alone or in combination with 4-PB, suberoylanilide hydroxamic acid (SAHA), C18, VX-445, and/or VX-661, significantly corrected both the traffic and the activity of Abcb11^R1128C. Such correctors could represent new pharmacological insights for improving the condition of patients with ABCB11 deficiency due to missense variations affecting the transporter’s traffic. Full article