Medicinal chemistry strategies to discover P-glycoprotein inhibitors: An update

SMART-assisted discovery of butenolides from the marine-derived Aspergillus sp. NBU4698 with multidrug resistance reversing and anti-inflammatory activity

Using together HSQC NMR-guided fractionation and an invivo screening zebrafish model for bioactivity-guided fractionation, four previously undescribed butenolides, perbutanolides A-D (1-4), were isolated from the marine-derived Aspergillus sp. NBU4698. HSQC NMR-based Small Molecule Accurate Recognition Technology (SMART 2.0) was used to simplify the process of discovering and characterizing these structurally related natural products. The structures and absolute configurations were determined by HRESIMS, NMR, polarimetry, and ECD calculations. All the compounds were evaluated for multidrug resistance (MDR) reversing activity in a zebrafish model, and compound 1 induced significant MDR reversal activity by inhibiting PXR-regulated efflux transporters. In addition, compounds 1-3 exhibited a moderate inhibitory effect on pro-inflammatory mediators in RAW264.7 macrophage cells. This is the first report of MDR reversal activity for marine-derived fungal butenolides. These results provide new insights for designing and developing probes and new drugs that can inhibit MDR.

Aptamer inhibits P-glycoprotein efflux function via the Wnt/β-catenin signaling pathway

Inhibiting permeability glycoprotein (P-gp) efflux is a strategy to enhance drug efficacy or overcome multidrug resistance in tumors. However, whether P-gp aptamer (APTP-gp, an 81 bp ssDNA) inhibits P-gp efflux is unknown. Increased Rho123 uptake was observed in the rat brain and intestine. Bidirectional transport of Rho123 indicated that 100 nM of APTP-gp inhibited P-gp activity with inhibition ratios of 75.0 % in Caco-2 and 60.5 % in hCMEC/D3 cells. The apparent permeability coefficients (Papp) from the apical (AP) to basolateral (BL) sides significantly increased by 129.4 % in Caco-2 and 8.0 % in hCMEC/D3 cells, respectively. The Papp from the BL→AP sides in the two cell lines decreased. P-gp mRNA and protein expression in the rat ileum, brain, and two cell lines markedly decreased following APTP-gp exposure. APTP-gp downregulated Wnt3, pho-Dvl2, β-catenin expression and decreased the ratio of pho-GSK-3β to GSK-3β in the rat ileum and brain. Molecular docking analysis suggested that APTP-gp interact with Wnt/β-catenin signaling pathway proteins at various amino acid sites. The present study reports a novel a novel nucleic acid-based P-gp inhibitor, which may benefit for enhancing drug efficacy or overcome multidrug resistance in clinical application.

P-Glycoprotein as a Therapeutic Target in Hematological Malignancies: A Challenge to Overcome

P-glycoprotein (P-gp), a transmembrane efflux pump encoded by the ABCB1/MDR1 gene, is a major contributor to multidrug resistance in hematological malignancies. These malignancies, arising from hematopoietic precursors at various differentiation stages, can manifest in the bone marrow, circulate in the bloodstream, or infiltrate tissues. P-gp overexpression in malignant cells reduces the efficacy of chemotherapeutic agents by actively expelling them, decreasing intracellular drug concentrations, and promoting multidrug resistance, a significant obstacle to successful treatment. This review examines recent advances in combating P-gp-mediated resistance, including the development of novel P-gp inhibitors, innovative drug delivery systems (e.g., nanoparticle-based delivery), and strategies to modulate P-gp expression or activity. These modulation strategies encompass targeting relevant signaling pathways (e.g., NF-κB, PI3K/Akt) and exploring drug repurposing. While progress has been made, overcoming P-gp-mediated resistance remains crucial for improving patient outcomes. Future research directions should prioritize the development of potent, selective, and safe P-gp inhibitors with minimal off-target effects, alongside exploring synergistic combination therapies with existing chemotherapeutics or novel agents to effectively circumvent multidrug resistance in hematological malignancies.

In vitro modulating effect and molecular docking of stilbene derivatives on P-gp efflux transporter

Highly expressed P-glycoprotein (P-gp) in cancer cells reduces chemotherapeutic effectiveness by transporting drugs out of the cells. This study evaluated the potential of eight phenanthrene-structured stilbenoids isolated from orchids in modulating P-gp activity. Molecular docking studies were conducted to predict the best-fitting stilbenoids for P-gp binding domains, and a substrate uptake assay was used to assess their effects. Our results indicate that the modulating effects were influenced by the number and arrangement of hydroxyl or methoxyl substitutions on the phenanthrene structure. Among the tested compounds, 1-(4-hydroxybenzyl)-4,6-dimethoxy-9,10-dihydrophenanthrene-2,7-diol (compound 8) exhibited the highest potency in modulating P-gp activity, with the best alignment to the P-gp binding sites.

Custom-Designed Robust MOF-Catalyst for Scalable 1,4-DHP Drugs With H-Bonding-Mediated Tandem Hantzsch Condensation and Shape-Reliant Friedel-Crafts Alkylation

Flanked -NH2 functionality, polar carbonyl moiety and intrinsically unsaturated [Zn2(CO2)2(ATz)4] center-decked micropores in an ultra-robust metal-organic framework (MOF) are reported, assembled from bent dicarboxylate and triazole (ATz) ligand. The MOF serves as one-of-a-kind tandem Hantzsch condensation catalyst to yield a multitude of 1,4-dihydropyridines (1,4-DHPs) with low catalyst loading, short reaction duration at moderate temperature. Importantly, the MOF is used in the synthesis of six 1,4-DHP-based therapeutic molecules in >95% conversion, which are characterized in purest form via X-ray crystallography besides other spectroscopic analyses. Apart from gram-scale production of ethidine molecule at 40 °C in just 30 min, oxodipine drug is first-time synthesized by any framework-based catalyst. This mixed-ligand MOF further demonstrates highly recyclable Friedel-Crafts (FC) alkylation of indole and β-nitrostyrene and covers twenty electronically diverse substrates under relatively green conditions. Strikingly, larger-sized substrates can't diffuse inside the micropores and exemplifies rarest shape-reliant C‒C coupling reaction. Contrary to conventional Lewis-acid activation, the maximum contribution from hydrogen-bonding site promotes both tandem multi-component and FC reactions, as comprehensively supported from control experiments, analyte-induced emission articulation, inferior activity of task-specific site-truncated isoskeletal MOF, and density functional theory results. This work provides a major advancement on unconventional heterogeneous catalysis to produce valuable products.

A comprehensive review on overcoming the multifaceted challenge of cancer multidrug resistance: The emerging role of mesoporous silica nanoparticles

Multidrug resistance (MDR) is a significant challenge in tumor treatment, severely reducing the effectiveness of anticancer drugs and contributing to high mortality rates. This article overviews the various factors involved in the development of MDR, such as changes in drug targets, increased DNA repair mechanisms, and the impact of the tumor microenvironment. It also emphasizes the potential of mesoporous silica nanoparticles (MSNs) as a drug delivery system to combat MDR. With their unique characteristics-such as a high surface area, adjustable pore sizes, and the ability to be functionalized for targeted delivery-MSNs serve as excellent carriers for the simultaneous delivery of chemotherapeutics and siRNAs aimed at reversing resistance pathways. The paper focuses on innovative methods using MSNs for direct intranuclear delivery of their cargos to overcome efflux barrier and improve the effectiveness of combination therapies. This review highlights a promising approach for enhancing cancer treatment outcomes by integrating advanced nanotechnology with traditional therapies, addressing the ongoing challenge of MDR in oncology.

Acridine-Based Chalcone 1C and ABC Transporters

Chalcones, potential anticancer agents, have shown promise in the suppression of multidrug resistance due to the inhibition of drug efflux driven by certain adenosine triphosphate (ATP)-binding cassette (ABC) transporters. The gene and protein expression of chosen ABC transporters (multidrug resistance protein 1, ABCB1; multidrug resistance-associated protein 1, ABCC1; and breast cancer resistance protein, ABCG2) in human colorectal cancer cells (COLO 205 and COLO 320, which overexpress active ABCB1) was mainly studied in this work under the influence of a novel synthetic acridine-based chalcone, 1C. While gene expression dropped just at 24 h, compound 1C selectively suppressed colorectal cancer cell growth and greatly lowered ABCB1 protein levels in COLO 320 cells at 24, 48, and 72 h. It also reduced ABCC1 protein levels after 48 h. Molecular docking and ATPase tests show that 1C probably acts as an allosteric modulator of ABCB1. It also lowered galectin-1 (GAL1) expression in COLO 205 cells at 24 h. Functional tests on COLO cells revealed ABCB1 and ABCC1/2 to be major contributors to multidrug resistance in both. Overall, 1C transiently lowered GAL1 in COLO 205 while affecting important functional ABC transporters, mostly ABCB1 and to a lesser extent ABCC1 in COLO 320 cells. COLO 320's absence of GAL1 expression points to a possible yet unknown interaction between GAL1 and ABCB1.

Adamantane-Quinoxalone Hybrids: Precision Chemotypes and Their Molecular Mechanisms in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is an aggressive blood cancer with a poor prognosis, especially when diagnosed late. Around 10-15% of cases involve the specific chromosomal abnormality t(8;21), which drives uncontrolled myeloid cell proliferation and contributes to disease onset. Despite advances in AML research and treatment protocols, outcomes for t(8;21) AML remain stagnant, as patients receive standard, nonspecific chemotherapies. This one-size-fits-all approach targets both cancerous and healthy cells, leading to unwanted toxicity and highlighting the urgent need for targeted therapies. In this study, we present a precision chemotype based on a quinoxalone-tethered adamantane framework developed via a metal- and light-free protocol. The compound selectively inhibits t(8;21) AML cell proliferation and induces cell death by disrupting growth and metabolic pathways, as demonstrated through bioassays, RNA sequencing, and proteomic analysis. Notably, it spares other leukemic and solid cancer cells, underscoring its specificity and potential as a targeted therapy for t(8;21) AML.

Cytotoxic Effect of Escitalopram/Etoposide Combination on Etoposide-Resistant Lung Cancer

Background: Antidepressants are a class of pharmaceuticals utilized for the management of many psychiatric disorders, including depression. A considerable number of antidepressants, particularly selective serotonin reuptake inhibitors (SSRIs), have been documented to demonstrate significant anticancer properties in various cancer cell lines. Objectives: The aim of this study was to evaluate the selective cytotoxic and apoptotic effects of escitalopram oxalate (ES) alone and in combination with etoposide (ET) on ET-resistant A549 (A549/90E) lung cancer cells. Methods: The cytotoxic effects of the drugs were determined by CCK-8, trypan blue, and neutral red assays. Apoptosis was observed by Annexin V fluorescein isothiocyanate (FITC)/PI and mitochondrial membrane potential (ΔΨm) assays. Moreover, the effects of the drugs, alone and in combination, on apoptosis-related proteins, caspase-3, PTEN, and resistance-related P-gP were determined by ELISA. The relationship between drugs and lung cancer was determined with protein-protein interaction (PPI) network analysis. Results: Our results revealed that ES significantly exerted cytotoxic effects on both wild-type and A549/90E cells compared with BEAS-2B cells. The IC50 values of 48.67 and 51.6 μg/mL obtained for ET and ES, respectively, at the end of 24 h of incubation for A549 cells were applied reciprocally for each cell by including BEAS-2B together with the 2xIC50 and ½ IC50 values. The results of each combination were statistically evaluated with combination indices (CIs) obtained using the Compusyn synergistic effect analysis program. Combination doses with a synergistic effect in A549 and A549/90E cells and an antagonistic effect in BEAS-2B cells have been determined as ½ IC50 for ET and ½ IC50 for ES. ET ½ IC50, ES ½ IC50, and an ET ½ IC50 + ES ½ IC50 combination caused 18.37%, 55.19%, and 57.55% death in A549 cells, whereas they caused 44.9%, 22.4%, and 51.94% death in A549/90E cells, respectively. In A549 cells, the combination of ES ½ IC50 and ET ½ IC50 caused increased levels of caspase-3 (p < 0.01) and P-gP (p < 0.001), while PTEN levels remained unchanged. The combination resulted in an increase in caspase-3 (p < 0.001) and PTEN (p < 0.001) amounts, alongside a decrease in P-gP (p < 0.01) levels in A549/90E cells. The death mechanism induced by the combination was found to be apoptotic by Annexin V-FITC and ΔΨm assays. Conclusions: Based on our findings, ES was observed to induce cytotoxic and apoptotic activities in A549/90E cells in vitro. ES in combination therapy is considered to be effective to overcome ET resistance by reducing the amount of P-gP in A549/90E cells.

Combating chemoresistance: Current approaches & nanocarrier mediated targeted delivery

Chemoresistance, a significant challenge in effective cancer treatment needs clear elucidation of the underlying molecular mechanism for the development of novel therapeutic strategies. Alterations in transporter pumps, oncogenes, tumour suppressor genes, mitochondrial function, DNA repair processes, autophagy, epithelial-mesenchymal transition (EMT), cancer stemness, epigenetic modifications, and exosome secretion lead to chemoresistance. Despite notable advancements in targeted cancer therapies employing both small molecules and macromolecules success rates remain suboptimal due to adverse effects like drug efflux, target mutation, increased mortality of normal cells, defective apoptosis, etc. This review proposes an advanced nanotechnological technique precisely targeting molecular determinants of chemoresistance which holds promise for enhancing cancer treatment efficacy. Further, the review explores various cancer hallmarks and pathways implicated in chemoresistance, current therapeutic modalities, and their limitations. It advocates the combination of nanoparticle-conjugated conventional drugs and natural compounds to specifically target molecular pathways that can potentially reverse or minimize chemoresistance incidences in cancer patients.

Design, Synthesis, and Biological Evaluation of Marchantin C-NO Donor Hybrids for Overcoming Pgp-Mediated Drug Resistance by Targeting Lysosome

A series of marchantin C-NO donor hybrids were designed, synthesized, and evaluated for their antitumor activity in vitro and in vivo. Notably, MC-furoxan hybrid 14 exhibited the best selective inhibitory activity against MCF-7/ADR (IC50 = 0.024 μM) with 883 times potency compared with MCF-7 cells (IC50 = 21.20 μM), and the cytotoxicity toward A549/Taxol (IC50 = 1.43 μM) increased 17-fold compared with that in A549 cells (IC50 = 23.75 μM). Preliminary pharmacological studies revealed that 14 could "hijack" the lysosomal Pgp and release NO to produce reactive oxygen species (ROS) in lysosomes, resulting in lysosomal membrane permeabilization (LMP) and potentiated cytotoxicity. Additionally, compound 14 achieved stronger antitumor activity and superior biosafety at relatively low doses than paclitaxel in the A549/Taxol xenograft model. In summary, this study provides a promising strategy for the design of such MC-furoxan hybrids like 14 to overcome MDR via the utilization of lysosomal Pgp transport activity.

Novel insights into taxane pharmacology: An update on drug resistance mechanisms, immunomodulation and drug delivery strategies

Taxanes are effective in several solid tumors. Paclitaxel, the main clinically available taxane, was approved in the early nineties, for the treatment of ovarian cancer and later on, together with the analogs docetaxel and cabazitaxel, for other malignancies. By interfering with microtubule function and impairing the separation of sister cells at mitosis, taxanes act as antimitotic agents, thereby counteracting the high proliferation rate of cancer cells. The action of taxanes goes beyond their antimitotic function because their main cellular targets, the microtubules, participate in multiple processes such as intracellular transport and cell shape maintenance. The clinical efficacy of taxanes is limited by the development of multiple resistance mechanisms. Among these, extracellular vesicles have emerged as new players. In addition, taxane metronomic schedules shows an impact on the tumor microenvironment reflected by antiangiogenic and immunomodulatory effects, an aspect of growing interest considering their inclusion in treatment regimens with immunotherapeutics. Preclinical studies have paved the bases for synergistic combinations of taxanes both with conventional and targeted agents. A variety of drug delivery strategies have provided novel opportunities to increase the drug activity. The ability of taxanes to orchestrate different cellular effects amenable to modulation suggests novel options to improve cures in lethal malignancies.

Understanding Efflux-Mediated Multidrug Resistance in Botrytis cinerea for Improved Management of Fungicide Resistance

Botrytis cinerea is a major fungal pathogen infecting over 1400 plant species. It poses a significant threat to agriculture due to multiple fungicide resistance and multidrug resistance, involves resistance to fungicides with different modes of action. Multiple fungicide resistance is mostly due to an accumulation of point mutations in target genes over time, and MDR is result from efflux (e-MDR) and metabolism (m-MDR). This review introduces the occurrence of e-MDR of B. cinerea, the key mechanisms, origins and management strategies of e-MDR in fields. New materials such as nanomaterials become a strategy to overcoming MDR via inhibition of ABC transporter. A deeper understanding of efflux-mediated MDR will provide a support for the MDR management of B. cinerea and the efficient utilization of fungicides.

Vodobatinib overcomes cancer multidrug resistance by attenuating the drug efflux function of ABCB1 and ABCG2

Multidrug resistance (MDR) remains a significant obstacle in cancer treatment, primarily attributable to the overexpression of ATP-binding cassette (ABC) transporters such as ABCB1 and ABCG2 within cancer cells. These transporters actively diminish the effectiveness of cytotoxic drugs by facilitating ATP hydrolysis-dependent drug efflux, thereby reducing intracellular drug accumulation. Given the absence of approved treatments for multidrug-resistant cancers and the established benefits of combining tyrosine kinase inhibitors (TKIs) with conventional anticancer drugs, we investigate the potential of vodobatinib, a potent c-Abl TKI presently in clinical trials, to restore sensitivity to chemotherapeutic agents in multidrug-resistant cancer cells overexpressing ABCB1 and ABCG2. Results indicate that vodobatinib, administered at sub-toxic concentrations, effectively restores the sensitivity of multidrug-resistant cancer cells to cytotoxic drugs in a concentration-dependent manner. Moreover, vodobatinib enhances drug-induced apoptosis in these cells by inhibiting the drug-efflux function of ABCB1 and ABCG2, while maintaining their expression levels. Moreover, we found that while vodobatinib enhances the ATPase activity of ABCB1 and ABCG2, the overexpression of these transporters does not induce resistance to vodobatinib. These results strongly suggest that increased levels of ABCB1 or ABCG2 are unlikely to play a significant role in the development of resistance to vodobatinib in cancer patients. Overall, our findings unveil an additional pharmacological facet of vodobatinib against ABCB1 and ABCG2 activity, suggesting its potential incorporation into combination therapy for a specific subset of patients with tumors characterized by high ABCB1 or ABCG2 levels. Further investigation is warranted to fully elucidate the clinical implications of this therapeutic approach.

Journey of PROTAC: From Bench to Clinical Trial and Beyond

Proteolysis-targeting chimeras (PROTACs) represent a transformative advancement in drug discovery, offering a method to degrade specific intracellular proteins. Unlike traditional inhibitors, PROTACs are bifunctional molecules that target proteins for elimination, enabling the potential treatment of previously "undruggable" proteins. This concept, pioneered by Crews and his team, introduced the use of small molecules to link a target protein to an E3 ubiquitin ligase, inducing ubiquitination and subsequent degradation of the target protein. By promoting protein degradation rather than merely inhibiting function, PROTACs present a novel therapeutic strategy with enhanced specificity and effectiveness, especially in areas such as cancer and neurodegenerative diseases. Since their initial discovery, the field of PROTAC research has rapidly expanded with numerous PROTACs now designed to target a wide range of disease-relevant proteins. The substantial research, investment, and collaboration across academia and the pharmaceutical industry reflect the growing interest in PROTACs. This Review discusses the journey of PROTACs from initial discovery to clinical trials, highlighting advancements and challenges. Additionally, recent developments in fluorescent and photogenic PROTACs, used for real-time tracking of protein degradation, are presented, showcasing the evolving potential of PROTACs in targeted therapy.

Transferrin-targeting pH-responsive and biodegradable mesoporous silica nanohybrid for nitric oxide-sensitized chemotherapy of cancer

Weakly acidic pH, low oxygen and high glutathione levels are the main characteristics of tumor cells. Taking advantage of the unique acidic microenvironment of tumor cells, acid-responsive mesoporous organosilica nanoparticles (AMON) were designed for nitric oxide (NO)-sensitized chemotherapy of tumors. AMON served as a nanocarrier co-loaded with a nitric oxide donor (NOD) and chemotherapeutic drug doxorubicin (DOX). Transferrin (Tf) was modified on the surface as a targeting ligand to form NOD&DOX@AMON. In vitro experiments showed that AMON could be completely degraded under acidic conditions (pH 5.0) after 48 h. NOD&DOX@AMON entered cells via transferrin receptor-mediated internalization and degraded in the acidic microenvironment to release its payloads. NOD released NO in presence of one-electron reducing substances like Glutathione (GSH) and ascorbic acid, inhibiting P-glycoprotein(P-gp) function and thereby increasing the intracellular concentration of DOX. In vivo distribution studies revealed that the nanohybrids accumulated maximally in tumor tissue 12 h after intravenous injection and exhibited significant inhibitory effects on HepG2 xenograft tumors. Western blot experiments demonstrated that NOD&DOX@AMON could inhibit the expression of drug resistance-associated proteins and was expected to be employed as a therapeutic approach for drug-resistant ttumors.

Core-Shell Nanoparticles with Sequential Drug Release Depleting Cholesterol for Reverse Tumor Multidrug Resistance

Multidrug resistance (MDR) facilitates tumor recurrence and metastasis, which has become a main cause of chemotherapy failure in clinical. However, the current therapeutic effects against MDR remain unsatisfactory, mainly hampered by the rigid structure of drug-resistant cell membranes and the uncontrolled drug release. In this study, based on a sequential drug release strategy, we engineered a core-shell nanoparticle (DOX-M@CaP@ATV@HA) depleting cholesterol for reverse tumor MDR. DOX-M@CaP@ATV@HA could accurately target tumor cells due to the active targetability of hyaluronic acid (HA) toward CD44 receptors. The calcium phosphate (CaP) shell was cleaved in the lysosomal acidic environment so that the cholesterol-lowering drug atorvastatin (ATV) was rapidly released to diminish cholesterol and P-glycoprotein (P-gp) level on the membrane, thereby boosting tumor cell drug uptake. Next, doxorubicin (DOX) was gradually released from the hydrophobic core of the mPEG-DSPE micelle, inflicting irreversible DNA damage and triggering apoptosis. The nanosystem was proven both in vitro and in vivo to reverse MDR effectively and exhibited a remarkable therapeutic efficacy on drug-resistant tumors with high biosafety. In conclusion, DOX-M@CaP@ATV@HA effectively reverses MDR via cholesterol depletion, which provides an innovative strategy for tumor MDR treatment.

Chromones Featuring a [6,6]-Spiroketal Moiety Produced by Coculture of the Endophytic Fungi Chaetomium virescens and Xylaria Grammica

Under the guidance of HPLC-DAD analysis, ten new chromones featuring a rare [6,6]-spiroketal moiety, namely chaetovirexylariones A-J (1-10), together with two known congeners (11-12), were isolated from coculture of the endophytic fungi Chaetomium virescens and Xylaria grammica, from the rhizome of the medicinal plant Smilax glabra Roxb. Their structures were elucidated via a combination of NMR and HRESIMS data, and the absolute configurations of 1-10 were determined by the chemical conversion and single-crystal X-ray diffraction (Cu Kα) experiments, as well as the comparison of the experimental and calculated electronic circular dichroism (ECD) data. Compound 6 is the first report as a racemate of this type of natural product. Compound 10 represents the first example of a [6,6]-spiroketal chromone bearing a 5-amino-3-methyl-2-pentenoic acid fragment. Compound 8 demonstrated a reduction in PTX resistance of SW620/AD300 by a factor of 45, and had the potential to be an effective P-gp inhibitor and an antitumor chemotherapy sensitizer.

Role of long non-coding RNAs and natural products in prostate cancer: insights into key signaling pathways

Prostate cancer (PC) ranks among the most prevalent cancers in males. Recent studies have highlighted intricate connections between long non-coding RNAs (lncRNAs), natural products, and cellular signaling in PC development. LncRNAs, which are RNA transcripts without protein-coding function, influence cell growth, programmed cell death, metastasis, and resistance to treatments through pathways like PI3K/AKT, WNT/β-catenin, and androgen receptor signaling. Certain lncRNAs, including HOTAIR and PCA3, are associated with PC progression, with potential as diagnostic markers. Natural compounds, such as curcumin and resveratrol, demonstrate anticancer effects by targeting these pathways, reducing tumor growth, and modulating lncRNA expression. For instance, curcumin suppresses HOTAIR levels, hindering PC cell proliferation and invasion. The interaction between lncRNAs and natural compounds may open new avenues for therapy, as these substances can simultaneously impact multiple signaling pathways. These complex interactions offer promising directions for developing innovative PC treatments, enhancing diagnostics, and identifying new biomarkers for improved prevention and targeted therapy. This review aims to map the multifaceted relationship among natural products, lncRNAs, and signaling pathways in PC pathogenesis, focusing on key pathways such as AR, PI3K/AKT/mTOR, WNT/β-catenin, and MAPK, which are crucial in PC progression and therapy resistance. Regulation of these pathways by natural products and lncRNAs could lead to new insights into biomarker identification, preventive measures, and targeted PC therapies.

Design, synthesis and biological evaluation of biaryl amide derivatives as modulators of multi-drug resistance

The emergence of multi-drug resistance (MDR) presents a significant impediment to the efficacy of cancer treatment. Aberrant expression of ABC (ATP-binding cassette) transporters is acknowledged as one of the underlying factors contributing to MDR. P-glycoprotein (P-gp, MDR1, ABCB1), breast cancer resistance protein (BCRP, ABCG2), and MDR-associated protein 1 (MRP1, ABCC1) are members of the ABC transporter, and their over-expression usually occurs in drug-resistant tumor cells. In this work, the structure-activity relationships of the biaryl amide skeleton were systematically investigated via structural optimization step by step, which led to the identification of an exceptionally potent resistance reversal agent, D2. Compound D2 effectively reversed MDR to paclitaxel and cisplatin in A2780/T, A2780/CDDP and A549/T cell lines. It could directly bind to P-gp and downregulate the expression of both P-gp and MRP1. The treatment with D2 increased the intracellular accumulation of Rh123 and inhibited P-gp-mediated drug efflux of Rh123 in A2780/T cells. Therefore, compound D2 exhibits promising potential in overcoming multidrug resistance (MDR) induced by P-gp in cancer.

Ganoderma lucidum extract reverses multidrug resistance in breast cancer cells through inhibiting ATPase activity of the P-glycoprotein via MAPK/ERK signaling pathway

Breast cancer represents a persistent global health challenge, with multidrug resistance (MDR) posing a significant obstacle to effective treatment. In this study, we investigate the potential of Ganoderma lucidum extract (GLE) in reversing MDR in breast cancer and delve into the underlying mechanisms. We establish a robust in vitro 3D model of breast cancer with acquired MDR induced by paclitaxel. Utilizing the CCK-8 method, we assess the impact of GLE on cytotoxic drug sensitivity to determine its in vitro MDR reversal activity. Our results reveal that GLE enhances the toxicity of paclitaxel in breast cancer cells by inhibiting the ATPase activity of P-glycoprotein (P-gp) and increasing the intracellular and extracellular excretion of P-gp substrates, all without significantly altering P-gp protein expression. Additionally, GLE inhibits the phosphorylation of ERK1/2, suggesting that the enhanced sensitivity of breast cancer cells to paclitaxel by GLE is associated with the MAPK pathway. These findings indicate that GLE may inhibit P-gp-mediated drug efflux via the MAPK pathway, thus effectively overcoming paclitaxel resistance in breast cancer. This study provides valuable insights into the potential clinical applications of GLE in reversing multidrug resistance, offering hope for improved breast cancer treatment strategies.

In-silico-based lead optimization of hit compounds targeting mitotic kinesin Eg5 for cancer management

Lead optimization is vital for turning hit compounds into therapeutic drugs. This study builds upon a prior in silico research, where the hit compounds had better binding affinity and stability compared to a reference drug. Using a genetic algorithm, 12,500 analogs of the top compounds from the prior study were generated. Virtual screening was done using a quantitative structure-activity relationship (QSAR) model. Top analogs, selected based on pChembL values below 6.000nM, underwent molecular docking targeting Human Eg5. The top five analogs from this study (Compound 9794, Compound 8592, Compound 9786, Compound 2744, and Compound 3246) demonstrated strong binding energies and interactions with key amino acids (GLU 116, GLU 117, and ARG 119). MMGBSA analysis revealed comparable affinities to the co-crystallized ligand, suggesting the top analogs' potential as Human Eg5 inhibitors. Induced fit docking highlighted Compound 9786's superior efficacy. Quantum Polarized Ligand Docking indicated promising scores for Compounds 8592 and 9786. ADMET predictions offered insights into pharmacological properties, with all compounds predicted to be HIA-positive and non-carcinogenic. Further MD simulation study confirms the stability of the top compounds in the active site of Eg5. This study shows the significance of integrated strategies in drug design. However, in vitro and in vivo studies should be conducted for these promising candidates to confirm their efficacy as Eg5 inhibitors.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-024-00300-6.

Synergistic pH-responsive MUC-1 aptamer-conjugated Ag/MSN Janus nanoparticles for targeted chemotherapy, photothermal therapy, and gene therapy in breast cancer

Drug resistance in cancer treatment, primarily attributed to the overexpression of the multidrug resistance (MDR) gene, significantly hampers the effectiveness of chemotherapy. This mechanism, driven by the increased production of P-glycoprotein (P-gp) efflux pumps, highlights the urgent need for innovative strategies to combat drug resistance in cancer patients. This study explores the application of antisense technology to suppress MDR gene expression, while addressing the challenges of instability and limited cellular uptake associated with antisense oligonucleotides. We synthesized Janus silver-mesoporous silica nanoparticles (Ag/MSN JNPs) using a sol-gel method, characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS), revealing uniformly sized, dumbbell-shaped nanoparticles with an average size of 285 ± 5.12 nm. Doxorubicin (DOX) was loaded into the porous structure of the mesoporous silica, and JNPs were functionalized with chitosan (CS) to incorporate P-gp antisense and a MUC-1 aptamer, serving as a pH-responsive gatekeeper. Our findings indicate that the Ap-As-DOX-JNPs achieved a remarkable 89 ± 0.59 % cell death in drug-resistant MCF-7/ADR cells after 48 h, alongside an 80 % reduction in P-gp expression. The combination of DOX, antisense technology, and photothermal therapy utilizing these JNPs demonstrates a promising strategy to effectively overcome drug resistance. Notably, normal MCF-7 cells exhibited reduced viability from 39.11 ± 1.12 % to 30.05 ± 1.07 % when treated with DOX-JNPs under near-infrared (NIR) irradiation. These results underscore the potential of utilizing MUC-1 aptamer-conjugated Janus nanoparticles in conjunction with chitosan as a gatekeeper to enhance the efficacy of chemotherapy, photothermal therapy, and gene therapy in overcoming multidrug resistance in cancer treatment.

Wheat germ agglutinin modified mixed micelles overcome the dual barrier of mucus/enterocytes for effective oral absorption of shikonin and gefitinib

The combination of shikonin (SKN) and gefitinib (GFB) can reverse the drug resistance of lung cancer cells by affecting energy metabolism. However, the poor solubility of SKN and GFB limits their clinical application because of low bioavailability. Wheat germ agglutinin (WGA) can selectively bind to sialic acid and N-acetylglucosamine on the surfaces of microfold cells and enterocytes, and is a targeted biocompatible material. Therefore, we created a co-delivery micelle system called SKN/GFB@WGA-micelles with the intestinal targeting functions to enhance the oral absorption of SKN and GFB by promoting mucus penetration for nanoparticles via oral administration. In this study, Caco-2/HT29-MTX-E12 co-cultured cells were used to simulate a mucus/enterocyte dual-barrier environment, and HCC827/GR cells were used as a model of drug-resistant lung cancer. We aimed to evaluate the oral bioavailability and anti-tumor effect of SKN and GFB using the SKN/GFB@WGA-micelles system. In vitro and in vivo experimental results showed that WGA promoted the mucus penetration ability of micelles, significantly enhanced the uptake efficiency of enterocytes, improved the oral bioavailability of SKN and GFB, and exhibited good anti-tumor effects by reversing drug resistance. The SKN/GFB@WGA-micelles were stable in the gastrointestinal tract and provided a novel safe and effective drug delivery strategy.

A Revolutionary Approach for Combating Efflux Transporter-mediated Resistant Epilepsy: Advanced Drug Delivery Systems

Epilepsy is a persistent neurological condition that affects 60 million individuals globally, with recurrent spontaneous seizures affecting 80% of patients. Antiepileptic drugs (AEDs) are the main course of therapy for approximately 65% of epileptic patients, and the remaining 35% develop resistance to medication, which leads to drug-resistant epilepsy (DRE). DRE continues to be an important challenge in clinical epileptology. There are several theories that attempt to explain the neurological causes of pharmacoresistance in epilepsy. The theory that has been studied the most is the transporter hypothesis. Therefore, it is believed that upregulation of multidrug efflux transporters at the blood-brain barrier (BBB), such as P-glycoprotein (P-gp), which extrudes AEDs from their target location, is the major cause, leading to pharmacoresistance in epilepsy. The most effective strategies for managing this DRE are peripheral and central inhibition of P-gp and maintaining an effective concentration of the drug in the brain parenchyma. Presently, no medicinal product that inhibits Pgp is being used in clinical practice. In this review, several innovative and promising treatment methods, including gene therapy, intracranial injections, Pgp inhibitors, nanocarriers, and precision medicine, are discussed. The primary goal of this work is to review the P-gp transporter, its substrates, and the latest novel treatment methods for the management of DRE.

Advances in synthesis of novel annulated azecines and their unique pharmacological properties

Annulated azecines, mostly partially saturated benzo[d]azecine and dibenzo[c,g]azecine fusion isomers, constitute a unique class of alkaloids and nature-inspired azaheterocyclic compounds with interesting reactivity, physicochemical and biological properties. Due to difficulties associated with the synthesis of the benzazecine (or bioisosteric) scaffold they are not the focus of organic and medicinal chemists' consideration, whereas it is worth noting the range of their pharmacological activities and their potential application in medicinal chemistry. Herein, we reviewed the synthetic methodologies of arene-fused azecine derivatives known up to date and reported about the progress in disclosing their potential in drug discovery. Indeed, their conformational restriction or liberation drives their selectivity towards diverse biological targets, making them versatile scaffolds for developing drugs, including antipsychotic and anticancer drugs, but also small molecules with potential for anti-neurodegenerative treatments, as the recent literature shows.

Epigenetic and Cellular Reprogramming of Doxorubicin-Resistant MCF-7 Cells Treated with Curcumin

The MCF-7R breast cancer cell line, developed by treating the parental MCF-7 cells with increasing doses of doxorubicin, serves as a model for studying acquired multidrug resistance (MDR). MDR is a major challenge in cancer therapy, often driven by overexpression of the efflux pump P-glycoprotein (P-gp) and epigenetic modifications. While many P-gp inhibitors show promise in vitro, their nonspecific effects on the efflux pump limit in vivo application. Curcumin, a natural compound with pleiotropic action, is a nontoxic P-gp inhibitor capable of modulating multiple pathways. To explore curcumin's molecular effects on MCF-7R cells, we analyzed the expression of genes involved in DNA methylation and transcription regulation, including ABCB1/MDR1. Reduced representation bisulfite sequencing further unveiled key epigenetic changes induced by curcumin. Our findings indicate that curcumin treatment not only modulates critical cellular processes, such as ribosome biogenesis and cytoskeletal dynamics, but also reverses the resistant phenotype, toward that of sensitive cells. This study highlights curcumin's potential as an adjuvant therapy to overcome chemoresistance, offering new avenues for pharmacological strategies targeting epigenetic regulation to re-sensitize resistant cancer cells.

Potency and mechanism of p-glycoprotein chemosensitizers in rainbow trout (Oncorhynchus mykiss) hepatocytes

The membrane efflux transporter P-glycoprotein (P-gp, [ABCB1, MDR1]) exports a wide range of xenobiotic compounds, resulting in a continuous first line of defense against toxicant accumulation at basal expression levels, and contributing to the multixenobiotic resistance (MXR) phenotype at elevated expression levels. Relatively little information exists on P-gp inhibition in fish by chemosensitizers, compounds which lower toxicity thresholds for harmful P-gp substrates in complex mixtures. The effects of four known mammalian chemosensitizers (cyclosporin A [CsA], quinidine, valspodar [PSC833], and verapamil) on the P-gp-mediated transport of rhodamine 123 (R123) and cortisol in primary cultures of rainbow trout (Oncorhynchus mykiss) hepatocytes were examined. Competitive accumulation assays using 25 µM R123 or cortisol and varying concentrations of chemosensitizers (0-500 µM) were used. CsA, quinidine, and verapamil inhibited R123 export (IC50 values ± SE: 132 ± 60, 83.3 ± 27.2, and 43.2 ± 13.6 µM, respectively). CsA and valspodar inhibited cortisol export (IC50 values: 294 ± 106 and 92.2 ± 34.9 µM, respectively). In an ATP depletion assay, hepatocytes incubated with all four chemosensitizers resulted in lower free ATP concentrations, suggesting that they act via competitive inhibition. Chemosensitizers that inhibit MXR transporters are an important class of environmental pollutant, and these results show that rainbow trout transporters are inhibited by similar chemosensitizers (and mostly at similar concentrations) as seen in mammals and other fish species.

MiR-133 promotes the multidrug resistance of acute myeloid leukemia cells (HL-60/ADR) to daunorubicin

This study aimed to explore the role and molecular mechanism of miR-133 in multidrug resistance in acute myeloid leukemia (AML) and provide a new theoretical basis for the treatment and prognosis of AML patients. We performed experiments at the cellular level. RT‒qPCR and Western blotting were used to detect gene and protein expression; cell viability was measured with CCK-8 assays; apoptosis was detected via flow cytometry; and a dual-luciferase reporter gene assay was used to verify the binding between miR-133 and CXCL12. In this study, we found that miR-133 was upregulated in HL-60/ADR multidrug-resistant cells. Functionally, the inhibition of miR-133 alleviated the resistance of HL-60/ADR cells to daunorubicin (DNR). After inhibiting miR-133 in HL-60/ADR cells treated with DNR, the expression of the intracellular drug resistance-related proteins MRP562 and P-gp was inhibited, cell proliferation decreased, and apoptosis increased. Mechanistically, the NF-κB signaling pathway regulates the expression of miR-133 in HL-60/ADR cells, and the targeting of CXCL12 by miR-133 enhances the resistance of HL-60/ADR cells to DNR. In conclusion, the NF-κB signaling pathway regulates the expression of miR-133, and inhibiting miR-133 expression can target CXCL12 to increase the sensitivity of HL-60/ADR cells to DNR.

Borneol promotes berberine-induced cardioprotection in a rat model of myocardial ischemia/reperfusion injury via inhibiting P-glycoprotein expression

Berberine is reported to protect the heart against ischemia/reperfusion (I/R) injury, although efficacy is limited by low bioavailability. This study aims to determine whether borneol, a classic guiding drug, can enhance the cardioprotection induced by berberine and to clarify the underlying mechanisms involving P-glycoprotein (P-gp) in the heart. Adult male Sprague Dawley rats were gavaged with berberine (200 mg/kg) with or without borneol (100 mg/kg) for 7 consecutive days. A rat model of myocardial I/R injury was established by 30 min left coronary artery occlusion followed with 120 min reperfusion. The arrhythmia score, cardiac enzyme content, and myocardial infarct size were determined following reperfusion. Heart tissues were collected for Western blot and immunofluorescence analyses to measure the protein expression levels of Bcl-2, Bax, and P-gp. The results showed that administration of berberine protected the heart against I/R injury, as demonstrated by lower arrhythmia scores, serum cTnI contents, myocardial infarct size, and cardiomyocytes apoptosis. Moreover, borneol substantially enhanced the cardioprotective effects of berberine. Western blot and immunofluorescence analyses showed that both berberine and I/R injury did not alter P-gp expression in heart. In contrast, borneol combined with berberine significantly reduced P-gp levels by 43.4% (P = 0.0240). Interestingly, treatment with borneol alone decreased P-gp levels, but did not protect against myocardial I/R injury. These findings suggest that borneol, as an adjuvant drug, improved the cardioprotective effects of berberine by inhibiting P-gp expression in heart. Borneol combined with berberine administration provides a new strategy to protect the heart against I/R injury.

Synthesis and evaluation of novel tetrahydroisoquinoline-benzo[h]chromen-4-one conjugates as dual ABCB1/CYP1B1 inhibitors for overcoming MDR in cancer

The emergence of multidrug resistance (MDR) in malignant tumors is one of the major threats encountered currently by many chemotherapeutic agents. Among the various mechanisms involved in drug resistance, P-glycoprotein (P-gp, ABCB1), a member of the ABC transporter family that significantly increases the efflux of various anticancer drugs from tumor cells, and the metabolic enzyme CYP1B1 are widely considered to be two critical targets for overcoming MDR. Unfortunately, no MDR modulator has been approved by the FDA to date. In this study, based on pharmacophore hybridization, bioisosteric and fragment-growing strategies, we designed and synthesized 11 novel tetrahydroisoquinoline-benzo[h]chromen-4-one conjugates as dual ABCB1/CYP1B1 inhibitors. Among them, the preferred compound A10 exhibited the best MDR reversal activity (IC50 = 0.25 μM, RF = 44.4) in SW620/AD300 cells, being comparable to one of the most potent third-generation P-gp inhibitors WK-X-34. In parallel, this dual ABCB1/CYP1B1 inhibitory effect drives compound A10 exhibiting prominent drug resistance reversal activity to doxorubicin (IC50 = 4.7 μM, RF = 13.7) in ABCB1/CYP1B1-overexpressing DOX-SW620/AD300-1B1 resistant cells, which is more potent than that of the CYP1B1 inhibitor ANF. Furthermore, although compound A2 possessed moderate ABCB1/CYP1B1 inhibitory activity, it showed considerable antiproliferative activity towards drug-resistant SW620/AD300 and MKN45-DDP-R cells, which may be partly related to the increase of PUMA expression to promote the apoptosis of the drug-resistant MKN45-DDP-R cells as confirmed by proteomics and western blot assay. These results indicated that the tetrahydroisoquinoline-benzo[h]chromen-4-one conjugates may provide a fundamental scaffold reference for further discovery of MDR reversal agents.

Cell-Based Screen Identifies a Highly Potent and Orally Available ABCB1 Modulator for Treatment of Multidrug Resistance

Targeting ABCB1 is a promising strategy in combating multidrug resistance. Our cell-based phenotypic screening led to the discovery of novel triazolo[1,5-a]pyrimidone-based ABCB1 modulators. Notably, WS-917 was identified as a significant contributor to heightened sensitization of human colorectal adenocarcinoma cells (SW620/Ad300) to paclitaxel (IC50 = 5 nM). Mechanistic elucidation revealed that this compound substantially augmented intracellular paclitaxel and [3H]-paclitaxel, concurrently mitigating the efflux of [3H]-paclitaxel in SW620/Ad300 through the inhibition of ABCB1 efflux. The cellular thermal shift assay underscored its ability to stabilize ABCB1 through direct binding. Additionally, WS-917 induced stimulation of ABCB1 ATPase activity while exhibiting negligible inhibitory effect against CYP3A4. Remarkable was its capacity to enhance the sensitivity of SW620/Ad300 to paclitaxel, as well as the sensitivity of CT26/TAXOL to paclitaxel and PD-L1 inhibitor (Atezolizumab) in vivo, all achieved without inducing observable toxicity. The discovery of WS-917 holds promise for the development of more potent ABCB1 modulators.

Development of Natural-Product-Inspired ABCB1 Inhibitors Through Regioselective Tryptophan C3-Benzylation

The emergence of drug resistance in cancer cells eventually causing relapse is a serious threat that demands new advances. Upregulation of the ATP-dependent binding cassette (ABC) transporters, such as ABCB1, significantly contributes to the emergence of drug resistance in cancer. Despite more than 30 years of therapeutic discovery, and several generations of inhibitors against P-gp, the search for effective agents that minimize toxicity to human cells, while maintaining efflux pump inhibition is still underway. Leads derived from natural product scaffolds are well-known to be effective in various therapeutic approaches. Inspired by the biosynthetic pathway to Nocardioazine A, a marine alkaloid known to inhibit the P-gp efflux pump in cancer cells, we devised a regioselective pathway to create structurally unique indole-C3-benzyl cyclo-L-Trp-L-Trp diketopiperazines (DKPs). Using bat cells as a model to derive effective ABCB1 inhibitors for targeting human P-gp efflux pumps, we have recently identified exo-C3-N-Dbn-Trp2 (13) as a lead ABCB1 inhibitor. This C3-benzylated lead inhibited ABCB1 better than Verapamil.[21] Additionally, C3-N-Dbn-Trp2 restored chemotherapy sensitivity in drug-resistant human cancer cells and had no adverse effect on cell proliferation in cell cultures. For a clearer structure-activity relationship, we developed a broader screen to test C3-functionalized pyrroloindolines as ABCB1 inhibitors and observed that C3-benzylation is outperforming respective isoprenylated derivatives. Results arising from the molecular docking studies indicate that the interactions at the access tunnel between ABCB1 and the inhibitor result in a powerful predictor for the efficacy of the inhibitor. Based on fluorescence-based assays, we conclude that the most efficacious inhibitor is the p-cyano-derived exo-C3-N-Dbn-Trp2 (33 a), closely followed by the p-nitro substituted analogue. By combining assay results with molecular docking studies, we further correlate that the predictions based on the inhibitor interactions at the access tunnel provide clues about the design of improved ABCB1 inhibitors. As it has been well documented that ABCB1 itself is powerfully engaged in multi-drug resistance, this work lays the foundation for the design of a new class of inhibitors based on the endogenous amino acid-derived cyclo-L-Trp-L-Trp DKP scaffold.

Metal-Phenolic Networks: A Promising Frontier in Cancer Theranostics

The burgeoning field of cancer theranostics has been significantly advanced by the development of Metal-Phenolic Networks (MPNs), a new class of supramolecular architectures that integrate the advantages of metals and polyphenols. This review focuses on MPNs and their promising applications in cancer theranostics. Through a systematic literature search spanning from 2010 to 2023 in databases including PubMed, Scopus, and Web of Science. The period of search was justified by the rapid evolution of nanomaterials in cancer therapy, with MPNs emerging as a significant player in biomedical applications within the specified timeframe. This review discusses the classification and structure of polyphenolic compounds, as well as their mechanisms of action in cancer treatment. The applications of MPNs in chemotherapy drug delivery, photothermal therapy, chemodynamic therapy, biomedical imaging, and synergistic therapy are especially detailed. The authors emphasize the significance of MPNs in cancer nanomedicine and look forward to their future development directions.

Discovery of novel pyrazolo[1,5-a]pyrimidine derivatives as potent reversal agents against ABCB1-mediated multidrug resistance

The P-glycoprotein (ABCB1)-mediated multidrug resistance (MDR) has emerged as a significant impediment to the efficacy of cancer chemotherapy in clinical therapy, which could promote the development of effective agents for MDR reversal. In this work, we reported the exploration of novel pyrazolo [1,5-a]pyrimidine derivatives as potent reversal agents capable of enhancing the sensitivity of ABCB1-mediated MDR MCF-7/ADR cells to paclitaxel (PTX). Among them, compound 16q remarkably increased the sensitivity of MCF-7/ADR cells to PTX at 5 μM (IC50 = 27.00 nM, RF = 247.40) and 10 μM (IC50 = 10.07 nM, RF = 663.44). Compound 16q could effectively bind and stabilize ABCB1, and does not affect the expression and subcellular localization of ABCB1 in MCF-7/ADR cells. Compound 16q inhibited the function of ABCB1, thereby increasing PTX accumulation, and interrupting the accumulation and efflux of the ABCB1-mediated Rh123, thus resulting in exhibiting good reversal effects. In addition, due to the potent reversal effects of compound 16q, the abilities of PTX to inhibit tubulin depolymerization, and induce cell cycle arrest and apoptosis in MCF-7/ADR cells under low-dose conditions were restored. These results indicate that compound 16q might be a promising potent reversal agent capable of revising ABCB1-mediated MDR, and pyrazolo [1,5-a]pyrimidine might represent a novel scaffold for the discovery of new ABCB1-mediated MDR reversal agents.

Highly Potent and Intestine Specific P-Glycoprotein Inhibitor to Enable Oral Delivery of Taxol

Taxol is widely used in cancer chemotherapy; however, the oral absorption of Taxol remains a formidable challenge. Since the intestinal p-glycoprotein (P-gp) mediated drug efflux is one of the primary causes, the development of P-gp inhibitor is emerging as a promising strategy to realize Taxol's oral delivery. Because P-gp exists in many tissues, the non-selective P-gp inhibitors would lead to toxicity. Correspondingly, a potent and intestine specific P-gp inhibitor would be an ideal solution to boost the oral absorption of Taxol and avoid exogenous toxicity. Herein, we would like to report a highly potent and intestine specific P-gp inhibitor to enable oral delivery of Taxol in high efficiency. Through a multicomponent reaction and post-modification, various benzofuran-fused-piperidine derivatives were achieved and the biological evaluation identified 16 c with potent P-gp inhibitory activity. Notably, 16 c was intestine specific and showed almost none absorption (F=0.82 %), but possessing higher efficacy than Encequidar to improve the oral absorption of Taxol. In MDA-MB-231 xenograft model, the oral administration of Taxol and 16 c showed high therapeutic efficiency and low toxicity, thus providing a valuable chemotherapy strategy.

The colony-stimulating factor-1 receptor inhibitor edicotinib counteracts multidrug resistance in cancer cells by inhibiting ABCG2-mediated drug efflux

Chemotherapy treatment faces a major obstacle with the emergence of multidrug resistance (MDR), often attributed to the elevated expression of ATP-binding cassette (ABC) transporters such as ABCG2 and ABCB1 in cancer cells. These transporters hinder the efficacy of cytotoxic drugs via ATP hydrolysis-dependent efflux, leading to diminished intracellular drug levels. The scarcity of approved treatments for multidrug resistant cancers necessitates exploration of alternative strategies, including drug repositioning of molecular targeted agents to counteract ABCG2-mediated MDR in multidrug-resistant cancer cells. This study investigates the potential of edicotinib, a selective colony-stimulating factor-1 receptor (CSF-1R) tyrosine kinase inhibitor that is currently undergoing clinical trials for various diseases, to reverse MDR in ABCG2-overexpressing cancer cells. Our findings reveal that by attenuating the drug-efflux function of ABCG2 without altering its expression, edicotinib improves drug-induced apoptosis and reverses MDR in ABCG2-overexpressing multidrug-resistant cancer cells at non-toxic concentrations. Through ATPase activity analysis and molecular docking, potential interaction sites for edicotinib on ABCG2 were identified. These results underscore an additional pharmacological benefit of edicotinib against ABCG2 activity, suggesting its potential incorporation into combination therapies for patients with ABCG2-overexpressing tumors. Further research is warranted to validate these findings and explore their clinical implications.

Epertinib counteracts multidrug resistance in cancer cells by antagonizing the drug efflux function of ABCB1 and ABCG2

A significant hurdle in cancer treatment arises from multidrug resistance (MDR), often due to overexpression of ATP-binding cassette (ABC) transporters like ABCB1 and/or ABCG2 in cancer cells. These transporters actively diminish the efficacy of cytotoxic drugs by facilitating ATP hydrolysis-dependent drug efflux and reducing intracellular drug accumulation in cancer cells. Addressing multidrug-resistant cancers poses a significant challenge due to the lack of approved treatments, prompting the exploration of alternative avenues like drug repurposing (also referred to as drug repositioning) of molecularly targeted agents to reverse MDR-mediated by ABCB1 and/or ABCG2 in multidrug-resistant cancer cells. Epertinib, a potent inhibitor of EGFR and HER2 currently in clinical trials for solid tumors, was investigated for its potential to resensitize ABCB1- and ABCG2-overexpressing multidrug-resistant cancer cells to chemotherapeutic agents. Our findings reveal that at sub-toxic, submicromolar concentrations, epertinib restores the sensitivity of multidrug-resistant cancer cells to cytotoxic drugs in a concentration-dependent manner. The results demonstrate that epertinib enhances drug-induced apoptosis in these cancer cells by impeding the drug-efflux function of ABCB1 and ABCG2 without altering their expression. ATPase activity and molecular docking were employed to reveal potential interaction sites between epertinib and the drug-binding pockets of ABCB1 and ABCG2. In summary, our study demonstrates an additional pharmacological capability of epertinib against the activity of ABCB1 and ABCG2. These findings suggest that incorporating epertinib into combination therapy could be advantageous for a specific patient subset with tumors exhibiting high levels of ABCB1 or ABCG2, warranting further exploration.

Zosuquidar Promotes Antitumor Immunity by Inducing Autophagic Degradation of PD-L1

The intracellular distribution and transportation process are essential for maintaining PD-L1 (programmed death-ligand 1) expression, and intervening in this cellular process may provide promising therapeutic strategies. Here, through a cell-based high content screening, it is found that the ABCB1 (ATP binding cassette subfamily B member 1) modulator zosuquidar dramatically suppresses PD-L1 expression by triggering its autophagic degradation. Mechanistically, ABCB1 interacts with PD-L1 and impairs COP II-mediated PD-L1 transport from ER (endoplasmic reticulum) to Golgi apparatus. The treatment of zosuquidar enhances ABCB1-PD-L1 interaction and leads the ER retention of PD-L1, which is subsequently degraded in the SQSTM1-dependent selective autophagy pathway. In CT26 mouse model and a humanized xenograft mouse model, zosuquidar significantly suppresses tumor growth and accompanies by increased infiltration of cytotoxic T cells. In summary, this study indicates that ABCB1 serves as a negative regulator of PD-L1, and zosuquidar may act as a potential immunotherapy agent by triggering PD-L1 degradation in the early secretory pathway.

P-glycoprotein (P-gp)-driven cancer drug resistance: biological profile, non-coding RNAs, drugs and nanomodulators

Drug resistance has compromised the efficacy of chemotherapy. The dysregulation of drug transporters including P-glycoprotein (P-gp) can mediate drug resistance through drug efflux. In this review, we highlight the role of P-gp in cancer drug resistance and the related molecular pathways, including phosphoinositide 3-kinase (PI3K)-Akt, phosphatase and tensin homolog (PTEN) and nuclear factor-κB (NF-κB), along with non-coding RNAs (ncRNAs). Extracellular vesicles secreted by the cells can transport ncRNAs and other proteins to change P-gp activity in cancer drug resistance. P-gp requires ATP to function, and the induction of mitochondrial dysfunction or inhibition of glutamine metabolism can impair P-gp function, thus increasing chemosensitivity. Phytochemicals, small molecules and nanoparticles have been introduced as P-gp inhibitors to increase drug sensitivity in human cancers.

Soloxolone N-3-(Dimethylamino)propylamide Restores Drug Sensitivity of Tumor Cells with Multidrug-Resistant Phenotype via Inhibition of P-Glycoprotein Efflux Function

Multidrug resistance (MDR) remains a significant challenge in cancer therapy, primarily due to the overexpression of transmembrane drug transporters, with P-glycoprotein (P-gp) being a central focus. Consequently, the development of P-gp inhibitors has emerged as a promising strategy to combat MDR. Given the P-gp targeting potential of soloxolone amides previously predicted by us by an absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis, the aim of the current study was to experimentally verify their P-gp inhibitory and MDR reversing activities in vitro. Screening of soloxolone amides as modulators of P-gp using molecular docking and cellular P-gp substrate efflux assays revealed the ability of compound 4 bearing a N-3-(dimethylamino)propylamide group to interact with the active site of P-gp and inhibit its transport function. Blind and site-specific molecular docking accompanied by a kinetic assay showed that 4 directly binds to the P-gp transmembrane domain with a binding energy similar to that of zosuquidar, a third-generation P-gp inhibitor (ΔG = -10.3 kcal/mol). In vitro assays confirmed that compound 4 enhanced the uptake of Rhodamine 123 (Rho123) and doxorubicin (DOX) by the P-gp-overexpressing human cervical carcinoma KB-8-5 (by 10.2- and 1.5-fold, respectively (p < 0.05, unpaired t-test)) and murine lymphosarcoma RLS40 (by 15.6- and 1.75-fold, respectively (p < 0.05, unpaired t-test)) cells at non-toxic concentrations. In these cell models, 4 showed comparable or slightly higher activity than the reference inhibitor verapamil (VPM), with the most pronounced effect of the hit compound in Rho123-loaded RLS40 cells, where 4 was 2-fold more effective than VPM. Moreover, 4 synergistically restored the sensitivity of KB-8-5 cells to the cytotoxic effect of DOX, demonstrating MDR reversal activity. Based on the data obtained, 4 can be considered as a drug candidate to combat the P-gp-mediated MDR of tumor cells and semisynthetic triterpenoids, with amide moieties in general representing a promising scaffold for the development of novel therapeutics for tumors with low susceptibility to antineoplastic agents.

Comprehensive insights into herbal P-glycoprotein inhibitors and nanoformulations for improving anti-retroviral therapy efficacy

The worldwide HIV cases were 39.0 million (33.1-45.7 million) in 2022. Due to genetic variations, HIV-1 is more easily transmitted than HIV-2 and favours CD4 + T cells and macrophages, producing AIDS. Conventional HIV drug therapy has many drawbacks, including adherence issues leading to resistance, side effects that lower life quality, drug interactions, high costs limiting global access, inability to eliminate viral reservoirs, chronicity requiring lifelong treatment, emerging toxicities, and a focus on managing infections. Conventional dosage forms have bioavailability issues due to intestinal P-glycoprotein (P-gp) efflux, which can reduce anti-retroviral drug efficacy and lead to resistance. Use of phyto-constituents with P-gp regulating actions has great benefits for semi-synthetic modification to create formulations with greater bioavailability and reduced toxicity, which improves drug effectiveness. Lipid-based nanocarriers, solid lipid nanoparticles, nanostructured lipid carriers, polymer-based nanocarriers, and inorganic nanoparticles may inhibit P-gp efflux. Employing potent P-gp inhibitors within nanocarriers as a Trojan horse approach can enhance the intracellular accumulation of anti-retroviral drugs (ARDs), which are substrates for efflux transporters. This technique increases oral bioavailability and offers lower-dose options, boosting HIV patient compliance and lowering costs. Molecular docking of the inhibitor with P-gp may anticipate optimum binding and function, allowing drug efflux to be minimised.

Overcoming Cancer Drug Resistance with Nanoparticle Strategies for Key Protein Inhibition

Drug resistance remains a critical barrier in cancer therapy, diminishing the effectiveness of chemotherapeutic, targeted, and immunotherapeutic agents. Overexpression of proteins such as B-cell lymphoma 2 (Bcl-2), inhibitor of apoptosis proteins (IAPs), protein kinase B (Akt), and P-glycoprotein (P-gp) in various cancers leads to resistance by inhibiting apoptosis, enhancing cell survival, and expelling drugs. Although several inhibitors targeting these proteins have been developed, their clinical use is often hampered by systemic toxicity, poor bioavailability, and resistance development. Nanoparticle-based drug delivery systems present a promising solution by improving drug solubility, stability, and targeted delivery. These systems leverage the Enhanced Permeation and Retention (EPR) effect to accumulate in tumor tissues, reducing off-target toxicity and increasing therapeutic efficacy. Co-encapsulation strategies involving anticancer drugs and resistance inhibitors within nanoparticles have shown potential in achieving coordinated pharmacokinetic and pharmacodynamic profiles. This review discusses the mechanisms of drug resistance, the limitations of current inhibitors, and the advantages of nanoparticle delivery systems in overcoming these challenges. By advancing these technologies, we can enhance treatment outcomes and move towards more effective cancer therapies.

Machine Learning-Based Approach to Identify Inhibitors of Sterol-14-Alpha Demethylase: A Study on Chagas Disease

Objectives

Chagas Disease, caused by the parasite Trypanosoma cruzi, remains a significant public health concern, particularly in Latin America. The current standard treatment for Chagas Disease, benznidazole, is associated with various side effects, necessitating the search for alternative therapeutic options. In this study, we aimed to identify potential therapeutics for Chagas Disease through a comprehensive computational analysis.

Methods

A library of compounds derived from Cananga odorata was screened using a combination of pharmacophore modeling, structure-based screening, and quantitative structure-activity relationship (QSAR) analysis. The pharmacophore model facilitated the efficient screening of the compound library, while the structure-based screening identified hit compounds with promising inhibitory potential against the target enzyme, sterol-14-alpha demethylase.

Results

The QSAR model predicted the bioactivity of the hit compounds, revealing one compound to exhibit superior activity compared to benznidazole. Evaluation of the physicochemical, pharmacokinetic, toxicity, and medicinal chemistry properties of the hit compounds indicated their drug-like characteristics, oral bioavailability, ease of synthesis, and reduced toxicity profiles.

Conclusion

Overall, our findings present a promising avenue for the discovery of novel therapeutics for Chagas Disease. The identified hit compounds possess favorable drug-like properties and demonstrate potent inhibitory effects against the target enzyme. Further in vitro and in vivo studies are warranted to validate their efficacy and safety profiles.

The Role of PTEN in Chemoresistance Mediated by the HIF-1α/YY1 Axis in Pediatric Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. Current chemotherapy treatment regimens have improved survival rates to approximately 80%; however, resistance development remains the primary cause of treatment failure, affecting around 20% of cases. Some studies indicate that loss of the phosphatase and tensin homolog (PTEN) leads to deregulation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway, increasing the expression of proteins involved in chemoresistance. PTEN loss results in deregulation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and induces hypoxia-inducible factor 1-alpha (HIF-1α) expression in various cancers. Additionally, it triggers upregulation of the Yin Yang 1 (YY1) transcription factor, leading to chemoresistance mediated by glycoprotein p-170 (Gp-170). The aim of this study was to investigate the role of the PTEN/NF-κB axis in YY1 regulation via HIF-1α and its involvement in ALL. A PTEN inhibitor was administered in RS4;11 cells, followed by the evaluation of PTEN, NF-κB, HIF-1α, YY1, and Gp-170 expression, along with chemoresistance assessment. PTEN, HIF-1α, and YY1 expression levels were assessed in the peripheral blood mononuclear cells (PBMC) from pediatric ALL patients. The results reveal that the inhibition of PTEN activity significantly increases the expression of pAkt and NF-κB, which is consistent with the increase in the expression of HIF-1α and YY1 in RS4;11 cells. In turn, this inhibition increases the expression of the glycoprotein Gp-170, affecting doxorubicin accumulation in the cells treated with the inhibitor. Samples from pediatric ALL patients exhibit PTEN expression and higher HIF-1α and YY1 expression compared to controls. PTEN/Akt/NF-κB axis plays a critical role in the regulation of YY1 through HIF-1α, and this mechanism contributes to Gp-170-mediated chemoresistance in pediatric ALL.

Discovery of new tricyclic spiroindole derivatives as potent P-glycoprotein inhibitors for reversing multidrug resistance enabled by a synthetic methodology-based library

The discovery of novel and highly effective P-gp inhibitors is considered to be an effective strategy for overcoming tumor drug resistance. In this paper, a phenotypic screening via a self-constructed synthetic methodology-based library identified a new class of tricyclic spiroindole derivatives with excellent tumor multidrug resistance reversal activity. A stereospecific compound OY-103-B with the best reversal activity was obtained based on a detailed structure-activity relationship study, metabolic stability optimization and chiral resolution. For the VCR-resistant Eca109 cell line (Eca109/VCR), co-administration of 5.0 μM OY-103-B resulted in a reversal fold of up to 727.2, superior to the typical third-generation P-gp inhibitor tariquidar. Moreover, the compound inhibited the proliferation of Eca109/VCR cells in a concentration-dependent manner in plate cloning and flow cytometry. Furthermore, fluorescence substrate accumulation assay and chemotherapeutic drug reversal activity tests demonstrated that OY-103-B reversed tumor drug resistance via P-gp inhibition. In conclusion, this study provides a novel skeleton that inspires the design of new P-gp inhibitors, laying the foundation for the treatment of drug-resistant tumors.

Current advances in modulating tumor hypoxia for enhanced therapeutic efficacy

Hypoxia is a common feature of most solid tumors, which promotes the proliferation, invasion, metastasis, and therapeutic resistance of tumors. Researchers have been developing advanced strategies and nanoplatforms to modulate tumor hypoxia to enhance therapeutic effects. A timely review of this rapidly developing research topic is therefore highly desirable. For this purpose, this review first introduces the impact of hypoxia on tumor development and therapeutic resistance in detail. Current developments in the construction of various nanoplatforms to enhance tumor treatment in response to hypoxia are also systematically summarized, including hypoxia-overcoming, hypoxia-exploiting, and hypoxia-disregarding strategies. We provide a detailed discussion of the rationale and research progress of these strategies. Through a review of current trends, it is hoped that this comprehensive overview can provide new prospects for clinical application in tumor treatment. STATEMENT OF SIGNIFICANCE: As a common feature of most solid tumors, hypoxia significantly promotes tumor progression. Advanced nanoplatforms have been developed to modulate tumor hypoxia to enhanced therapeutic effects. In this review, we first introduce the impact of hypoxia on tumor progression. Current developments in the construction of various nanoplatforms to enhance tumor treatment in response to hypoxia are systematically summarized, including hypoxia-overcoming, hypoxia-exploiting, and hypoxia-disregarding strategies. We discuss the rationale and research progress of the above strategies in detail, and finally introduce future challenges for treatment of hypoxic tumors. By reviewing the current trends, this comprehensive overview can provide new prospects for clinical translatable tumor therapy.

Synthesis and evaluation of WK-X-34 derivatives as P-glycoprotein (P-gp/ABCB1) inhibitors for reversing multidrug resistance

The emergence of multidrug resistance (MDR) in malignant tumors is one of the leading threats encountered currently by many chemotherapeutic agents. A proposed strategy to overcome MDR is to disable the efflux function of P-glycoprotein (P-gp/ABCB1), a critical member of the ABC transporter family that significantly increases the efflux of various anticancer drugs from tumor cells. In this study, structural modification of a third-generation P-gp inhibitor WK-X-34 based on bioisosteric and fragment-growing strategies led to the discovery of the adamantane derivative PID-9, which exhibited the best MDR reversal activity (IC50 = 0.1338 μM, RF = 78.6) in this series, exceeding those of the reported P-gp inhibitors verapamil and WK-X-34. In addition, compared with WK-X-34, PID-9 showed decreased toxicity to cells. Furthermore, the mechanism studies revealed that the reversal activity of adamantane derivatives PID-5, PID-7, and PID-9 stemmed from the inhibition of P-gp efflux. These results indicated that compound PID-9 is the most effective P-gp inhibitor among them with low toxicity and high MDR reversal activity, which provided a fundamental structural reference for further discovery of novel, effective, and non-toxic P-gp inhibitors.

Composition, preparation methods, and applications of nanoniosomes as codelivery systems: a review of emerging therapies with emphasis on cancer

Nanoniosome-based drug codelivery systems have become popular therapeutic instruments, demonstrating tremendous promise in cancer therapy, infection treatment, and other therapeutic domains. An emerging form of vesicular nanocarriers, niosomes are self-assembling vesicles composed of nonionic surfactants, along with cholesterol or other amphiphilic molecules. This comprehensive review focuses on how nanosystems may aid in making anticancer and antibacterial pharmaceuticals more stable and soluble. As malleable nanodelivery instruments, the composition, types, preparation procedures, and variables affecting the structure and stability of niosomes are extensively investigated. In addition, the advantages of dual niosomes for combination therapy and the administration of multiple medications simultaneously are highlighted. Along with categorizing niosomal drug delivery systems, a comprehensive analysis of various preparation techniques, including thin-layer injection, ether injection, and microfluidization, is provided. Dual niosomes for cancer treatment are discussed in detail regarding the codelivery of two medications and the codelivery of a drug with organic, plant-based bioactive compounds or gene agents. In addition, niogelosomes and metallic niosomal carriers for targeted distribution are discussed. The review also investigates the simultaneous delivery of bioactive substances and gene agents, including siRNA, microRNA, shRNA, lncRNA, and DNA. Additional sections discuss the use of dual niosomes for cutaneous drug delivery and treating leishmanial infections, Pseudomonas aeruginosa, and Mycobacterium tuberculosis. The study concludes by delineating the challenges and potential routes for nanoniosome-based pharmaceutical codelivery systems, which will be useful for nanomedicine practitioners and researchers.

Structure-ATPase Activity Relationship of Rhodamine Derivatives as Potent Inhibitors of P-Glycoprotein CmABCB1

Understanding the transport and inhibition mechanisms of substrates by P-glycoprotein (P-gp) is one of the important approaches in addressing multidrug resistance (MDR). In this study, we evaluated a variety of rhodamine derivatives as potential P-gp inhibitors targeting CmABCB1, a P-gp homologue, with a focus on their ATPase activity. Notably, a Q-rhodamine derivative with an o,o'-dimethoxybenzyl ester moiety (RhQ-DMB) demonstrated superior affinity and inhibitory activity, which was further confirmed by a drug susceptibility assay in yeast strains expressing CmABCB1. Results from a tryptophan fluorescence quenching experiment using a CmABCB1 mutant suggested that RhQ-DMB effectively enters and binds to the inner chamber of CmABCB1. These findings underscore the promising potential of RhQ-DMB as a tool for future studies aimed at elucidating the substrate-bound state of CmABCB1.