Intracellular Drug Accumulation Research Articles

Lansoprazole (LPZ) reverses multidrug resistance (MDR) in cancer through impeding ATP-binding cassette (ABC) transporter-mediated chemotherapeutic drug efflux and lysosomal sequestration

AimsLansoprazole is one of the many proton pump inhibitors (PPIs) that acts more strongly with ABCB1 and ABCG2. The present study is to investigate the potential of lansoprazole on reversal of ABCB1/G2-mediated MDR in cancer, in vitro and in vivo. MethodsReversal studies and combination evaluation were conducted to determine the synergistic anti-MDR effects on lansoprazole. Lysosomal staining was used to determination of lansoprazole on ABCB1-mediated lysosomal sequestration. Substrate accumulation and efflux assays, ATPase activity, and molecular docking were conducted to evaluate lansoprazole on ABCB1/G2 functions. Western blot and immunofluorescence were used to detect lansoprazole on ABCB1/G2 expression and subcellular localization. MDR nude mice models were established to evaluate the effects of lansoprazole on MDR in vivo. ResultsLansoprazole attenuated ABCB1/G2-mediated MDR and exhibited synergistic effects with substrate drugs in MDR cells. In vivo experiments demonstrated that lansoprazole attenuated ABCB1/G2-mediated MDR and exhibited synergistic effects that augmented the sensitivity of substrate anticancer drugs in ABCB1/G2-mediated settings without obvious toxicity. Lansoprazole impeded lysosomal sequestration mediated by ABCB1, leading to a substantial increase in intracellular accumulation of substrate drugs. The effects of lansoprazole were not attributable to downregulation or alterations in subcellular localization of ABCB1/G2. Lansoprazole promoted the ATPase activity of ABCB1/G2 and competitively bound to the substrate-binding region of ABCB1/G2. ConclusionsThese findings present novel therapeutic avenues whereby the combination of lansoprazole and chemotherapeutic agents mitigates MDR mediated by ABCB1/G2 overexpression.

Marein, a novel natural product for restoring chemo-sensitivity to cancer cells through competitive inhibition of ABCG2 function.

The pivotal roles of ATP-binding cassette (ABC) transporters in drug resistance have been widely appreciated. Here we report that marein, a natural product from Coreopsis tinctoria Nutt, is a potent chemo-sensitizer in drug resistant cancer cells overexpressing ABCG2 transporter. We demonstrate that marein can competitively inhibit efflux activity of ABCG2 protein and increase the intracellular accumulation of the chemotherapeutic drugs that belong to substrate of this transporter. We further show that marein can bind to the conserved amino acid residue F439 of ABCG2, a critical site for drug-substrate interaction. Moreover, marein can significantly sensitize the ABCG2-expressing tumor cells to chemotherapeutic drugs such as topotecan, mitoxantrone, and Olaparib. This study reveals a novel role and mechanism of marein in modulating drug resistance, and may have important implications in treatment of cancers that are resistant to chemotherapeutic drugs that belong to the substrates of ABCG2 transporters.

Co-delivery of Paclitaxel/Atovaquone/Quercetin to regulate energy metabolism to reverse multidrug resistance in ovarian cancer by PLGA-PEG nanoparticles

Ovarian cancer is a malignant tumor that seriously endangers the lives of women, with chemotherapy being the primary clinical treatment. However, chemotherapy encounters the problem of generating multidrug resistance (MDR), mainly due to drug efflux induced by P-glycoprotein (P-gp), which decreases intracellular accumulation of chemotherapeutic drugs. The drugs efflux mediated by P-gp requires adenosine triphosphate (ATP) hydrolysis to provide energy. Therefore, modulating energy metabolism pathways and inhibiting ATP production may be a potential strategy to reverse MDR. Herein, we developed a PTX-ATO-QUE nanoparticle (PAQNPs) based on a PLGA-PEG nanoplatform capable of loading the mitochondrial oxidative phosphorylation (OXPHOS) inhibitor atovaquone (ATO), the glycolysis inhibitor quercetin (QUE), and the chemotherapeutic drug paclitaxel (PTX) to reverse MDR by inhibiting energy metabolism through multiple pathways. Mechanistically, PAQNPs could effectively inhibit the OXPHOS and glycolytic pathways of A2780/Taxol cells by suppressing the activities of mitochondrial complex III and hexokinase II (HK II), respectively, ultimately decreasing intracellular ATP levels in tumor cells. Energy depletion can effectively inhibit cell proliferation and reduce P-gp activity, increasing the chemotherapeutic drug PTX accumulation in the cells. Moreover, intracellular reactive oxygen species (ROS) is increased with PTX accumulation and leads to chemotherapy-resistant cell apoptosis. Furthermore, PAQNPs significantly inhibited tumor growth in the A2780/Taxol tumor-bearing NCG mice model. Immunohistochemical (IHC) analysis of tumor tissues revealed that P-gp expression was suppressed, demonstrating that PAQNPs are effective in reversing MDR in tumors by inducing energy depletion. In addition, the safety study results, including blood biochemical indices, major organ weights, and H&E staining images, showed that PAQNPs have a favorable in vivo safety profile. In summary, the results suggest that the combined inhibition of the two energy pathways, OXPHOS and glycolysis, can enhance chemotherapy efficacy and reverse MDR in ovarian cancer.

Upregulation of outer membrane porin gene ompC contributed to enhancement of azithromycin susceptibility in multidrug-resistant Escherichia coli.

The outer membrane (OM) in gram-negative bacteria contains proteins that regulate the passive or active uptake of small molecules for growth and cell function, as well as mediate the emergence of antibiotic resistance. This study aims to explore the potential mechanisms for restoring bacteria to azithromycin susceptibility based on transcriptome analysis of bacterial membrane-related genes. Transcriptome sequencing was performed by treating multidrug-resistant Escherichia coli T28R with azithromycin or in combination with colistin and confirmed by reverse transcription-quantitative PCR (RT-qPCR). Azithromycin enzyme-linked immunosorbent assay (ELISA) test, ompC gene overexpression, and molecular docking were utilized to conduct the confirmatory research of the potential mechanisms. We found that colistin combined with azithromycin led to 48 differentially expressed genes, compared to azithromycin alone, such as downregulation of tolA, eptB, lpxP, and opgE and upregulation of ompC gene. Interestingly, the addition of colistin to azithromycin differentially downregulated the mph(A) gene mediating azithromycin resistance, facilitating the intracellular accumulation of azithromycin. Also, overexpression of the ompC elevated azithromycin susceptibility, and colistin contributed to further suppression of the Mph(A) activity in the presence of azithromycin. These findings suggested that colistin firstly enhanced the permeability of bacterial OM, causing intracellular drug accumulation, and then had a repressive effect on the Mph(A) activity along with azithromycin. Our study provides a novel perspective that the improvement of azithromycin susceptibility is related not only to the downregulation of the mph(A) gene and conformational remodeling of the Mph(A) protein but also the upregulation of the membrane porin gene ompC.IMPORTANCEUsually, active efflux via efflux pumps is an important mechanism of antimicrobial resistance, such as the AcrAB-TolC complex and MdtEF. Also, bacterial porins exhibited a substantial fraction of the total number of outer membrane proteins in Enterobacteriaceae, which are involved in mediating the development of the resistance. We found that the upregulation or overexpression of the ompC gene contributed to the enhancement of resistant bacteria to azithromycin susceptibility, probably due to the augment of drug uptakes caused and the opportunity of Mph(A) function suppressed by azithromycin with colistin. Under the combination of colistin and azithromycin treatment, OmpC exhibited an increased selectivity for cationic molecules and played a key role in the restoral of the antibiotic susceptibility. Investigations on the regulation of porin expression that mediated drug resistance would be important in clinical isolates treated with antibiotics.

The Effect of TCP1 Expression on the Proliferation and the Accumulation of Intracellular Drug of HL60/A and HL60 Cell and Its Mechanism

To investigate the effect of TCP1 expression on the proliferation and the accumulation of intracellular drug of HL60/A and HL60 cells and its possible molecular mechanism. Lentiviral transfection technology was used to construct HL60/A and HL60 cells with knocked down or overexpressed TCP1 and their control cells. The efficiency of knockdown and overexpression was evaluated by Western blot. The cell proliferation was detected by CCK-8 assay. The intracellular drug accumulation was detected by laser confocal detection and flow cytometry. The expression levels of MRP1, P-gP and p-AKT were evaluated by flow cytometry and Western blot. After TCP1 was knocked down,the proliferation ability of HL60/A cells was significantly reduced, the accumulation of intracellular drug was significantly increased and the expression of MRP1 and P-gP protein were decreased. After TCP1 was overexpressed, the proliferation ability of HL60 was significantly increased, the accumulation of intracellular drug was significantly decreased and the expression of MRP1 and P-gP protein were increased. Intervention of LY294002 significantly antagonized the promotion on cell proliferation, the inhibition on intracellular drug accumulation and the expression of MRP1 and P-gP mediated by TCP1 overexpressing in HL60 cells. TCP1 can promote cell proliferation, improve the expression of MRP1 and P-gP by activating PI3K/AKT signal, and reduce intracellular drug accumulation.

Cancer sensitizing effect of deazaflavin analogs is associated with increased intracellular drug accumulation

As part of our efforts geared towards developing mechanism-based cancer sensitizing agents, we have previously synthesized and characterized novel deazaflavin analogs as potent tyrosyl DNA phosphodiesterase 2 (TDP2) inhibitors for combination treatments with topoisomerase II (TOP2) poisons. Interestingly, the sensitizing effect of a few analogs toward TOP2 poison etoposide (ETP) was associated with a significant increase in intracellular drug accumulation, which could be an alternative mechanism to boost the clinical efficacy of ETP in cancer chemotherapies. Hence, we evaluated more deazaflavin TDP2 inhibitors for their impact on drug retention in cancer cells. We found that all but one tested TDP2 inhibitors substantially increased the ETP retention in DT40 cells. Particularly, we identified an exceptionally potent analog, ZW-1226, which at 3 nM increased the intracellular ETP by 13-fold. Significantly, ZW-1226 also stimulated cellular accumulation of two other anticancer drugs, TOP2 poison teniposide and antifolate pemetrexed, and produced an effect more pronounced than those of ABC transporter inhibitors verapamil and elacridar in human leukemic CCRF-CEM cells toward ETP. Lastly, ZW-1226 potentiated the action of ETP in the sensitive human CCRF-CEM cells and a few resistant non-small-cell lung cancer cells, including H460 and H838 cells. Collectively, the results of this study strongly suggest that deazaflavin analog ZW-1226 could be an effective cancer sensitizing agent which warrants further investigation.

The role of ABCC10/MRP7 in anti-cancer drug resistance and beyond

Multidrug resistance protein 7 (MRP7), also known as ATP-binding cassette (ABC) transporter subfamily C10 (ABCC10), is an ABC transporter that was first identified in 2001. ABCC10/MRP7 is a 171 kDa protein located on the basolateral membrane of cells. ABCC10/MRP7 consists of three transmembrane domains and two nucleotide binding domains. It mediates multidrug resistance of tumor cells to a variety of anticancer drugs by increasing drug efflux and results in reducing intracellular drug accumulation. The transport substrates of ABCC10/MRP7 include antineoplastic drugs such as taxanes, vinca alkaloids, and epothilone B, as well as endobiotics such as leukotriene C4 (LTC4) and estradiol 17 β-D-glucuronide. A variety of ABCC10/MRP7 inhibitors, including cepharanthine, imatinib, erlotinib, tariquidar, and sildenafil, can reverse ABCC10/MRP7-mediated MDR. Additionally, the presence or absence of ABCC10/MRP7 is also closely related to renal tubular dysfunction, obesity, and other diseases. In this review, we discuss: 1) Structure and functions of ABCC10/MRP7; 2) Known substrates and inhibitors of ABCC10/MRP7 and their potential therapeutic applications in cancer; and 3) Role of ABCC10/MRP7 in non-cancerous diseases.

Ivermectin antiviral activity against Varicellovirus bovinealpha 1: assessment of intracellular drug accumulation in virus-infected cells.

Varicellovirus bovinealpha 1 (formerly bovine alphaherpesvirus type 1, BoAHV-1) is associated with several syndromes in cattle, including respiratory disease and is one of the main agents involved in the bovine respiratory disease complex (BRDC). Its infectious cycle is characterized by latent infections with sporadic virus reactivation and transmission. Although the acute disease can be prevented by the use of vaccines, specific therapeutic measures are not available. Ivermectin (IVM) is a semi-synthetic avermectin with a broad-spectrum antiparasitic activity, which has previously shown to have potential as an antiviral drug. In this study, IVM antiviral activity against BoAHV-1 was characterized in two cell lines (MDBK [Madin Darby bovine kidney] and BT [bovine turbinate]), including the measurement of intracellular drug accumulation within virus-infected cells. IVM antiviral activity was assessed at three different drug concentrations (1.25, 2.5 and 5µM) after incubation for 24, 48 and 72h. Slight cytotoxicity was only observed with 5µM IVM. Even the lowest IVM dose was able to induce a significant reduction in virus titers in both cell lines. These findings indicate that the antiviral effects of IVM were evident in our experimental model within the range of concentrations achievable through therapeutic in vivo administration. Consequently, additional in vivo trials are necessary to validate the potential utility of these results in effectively managing BoAHV-1 in infected cattle.

An insights into emerging trends to control the threats of antimicrobial resistance (AMR): an address to public health risks.

Antimicrobial agents are used to treat microbial ailments, but increased use of antibiotics and exposure to infections in healthcare facilities and hospitals as well as the excessive and inappropriate use of antibiotics at the society level lead to the emergence of multidrug-resistant (MDR) bacteria. Antimicrobial resistance (AMR) is considered a public health concern and has rendered the treatment of different infections more challenging. The bacterial strains develop resistance against antimicrobial agents by limiting intracellular drug accumulation (increasing efflux or decreasing influx of antibiotics), modification and inactivation of drugs and its targets, enzymatic inhibition, and biofilm formation. However, the driving factors of AMR include the sociocultural and economic circumstances of a country, the use of falsified and substandard medicines, the use of antibiotics in farm animals, and food processing technologies. These factors make AMR one of the major menaces faced by mankind. In order to promote reciprocal learning, this article summarizes the current AMR situation in Pakistan and how it interacts with the health issues related to the COVID-19 pandemic. The COVID-19 pandemic aids in illuminating the possible long-term impacts of AMR, which are less immediate but not less severe since their measures and effects are equivalent. Impact on other sectors, including the health industry, the economy, and trade are also discussed. We conclude by summarizing the several approaches that could be used to address this issue.

Doxorubicin-loaded PEG-CdTe QDs conjugated with anti-CXCR4 mAbs: a novel delivery system for extramedullary multiple myeloma treatment

Extramedullary multiple myeloma (EMM) is defined as the presence of plasma cells outside the bone marrow of multiple myeloma patients, and its prognosis is poor. High-dose chemotherapy with autologous stem cell transplantation, as a good option on early lines of therapy, has retained the survival benefit of youny EMM patients, but is intolerant for the majority of old patients because of drug cytotoxicity. To essentially address the intolerance above, we designed a CXCR4-PEG-CdTe-DOX (where CXCR4: chemokine receptor 4; PEG-CdTe: polyethylene glycol-modified cadmium telluride; DOX:doxorubicin) nanoplatform. First, CXCR4 is highly expressed in extramedullary plasma cells. Second, PEG-CdTe a drug carrier that controls drug release, can reduce adverse reactions, prolong drug (e.g, DOX) circulation time in the body, and form a targeting carrier after connecting antibodies. In vitro experiments showed CXCR4-PEG-CdTe-DOX facilitated intracellular drug accumulation through active CXCR4 targeting and released DOX into the microenvironment in a pH-controlled manner, enhancing the therapeutic efficacy and apoptosis rate of myeloma cells (U266). Therefore, targeted chemotherapy mediated by CXCR4-PEG-CdTe-DOX is a promising option for EMM treatment.Graphical abstractFigure 1 Action mechanism of drug delivery pathway: CXCR4-PEG-CdTe-DOX nanocomplex can be targeted and close to MM cell membranes, effectively transport DOX into MM cells, and promote MM cell apoptosis.

FRAX486, a PAK inhibitor, overcomes ABCB1-mediated multidrug resistance in breast cancer cells.

The overexpression of P-glycoprotein (P-gp/ABCB1) is a leading cause of multidrug resistance (MDR). Hence, it is crucial to discover effective pharmaceuticals that counteract ABCB1-mediated multidrug resistance. FRAX486 is a p21-activated kinase (PAK) inhibitor. The objective of this study was to investigate whether FRAX486 can reverse ABCB1-mediated multidrug resistance, while also exploring its mechanism of action. The CCK8 assay demonstrated that FRAX486 significantly reversed ABCB1-mediated multidrug resistance. Furthermore, western blotting and immunofluorescence experiments revealed that FRAX486 had no impact on expression level and intracellular localization of ABCB1. Notably, FRAX486 was found to enhance intracellular drug accumulation and reduce efflux, resulting in the reversal of multidrug resistance. Docking analysis also indicated a strong affinity between FRAX486 and ABCB1. This study highlights the ability of FRAX486 to reverse ABCB1-mediated multidrug resistance and provides valuable insights for its clinical application.

Pemigatinib, a selective FGFR inhibitor overcomes ABCB1-mediated multidrug resistance in cancer cells

P-glycoprotein (P-gp/ABCB1) overexpression is one of the primary causes of multidrug resistance (MDR). Therefore, it is crucial to discover effective pharmaceuticals to combat multidrug resistance mediated by ABCB1. Pemigatinib is a selective the fibroblast growth factor receptor (FGFR) inhibitor that is used to treat a variety of solid tumors, Clinical Trials for Urothelial Carcinoma (NCT02872714) completed its research on Pemigatinib. This study aimed to determine whether Pemigatinib can reverse ABCB1-mediated multidrug resistance, as well as its mechanism of action. Pemigatinib substantially reversed ABCB1-mediated multidrug resistance, as determined by a CCK8 assay, and immunofluorescence experiments revealed that Pemigatinib had no effect on the intracellular localization of ABCB1. Pemigatinib was discovered to increase intracellular drug accumulation, thereby reversing multidrug resistance. In addition, Docking analysis revealed that Pemigatinib and ABCB1 have a high affinity for one another. This study concludes that Pemigatinib is capable of reversing the multidrug resistance mediated by ABCB1, offering ideas and references for the clinical application of Pemigatinib.

Quality by design (QbD) commended exploration of bosutinib loaded lipid nanocarriers for food effect attenuation and bioavailability enhancement in breast cancer

Bosutinib (BOS), a BCS class IV drug suffers from poor aqueous solubility and bioavailability along with significant food effect. Lipid nanocarriers (LNC) have the potential to circumvent bioavailability related issues associated with hydrophobic moieties. In this endeavor, we explore the potential of novel lipid nanocarriers to circumvent the bioavailability pitfalls, while minimizing food effect and pharmacokinetic variability. Quality by design and multi-variate analysis was adopted for the optimization of various process parameters during nanoparticle fabrication. The optimized particle size, polydispersity index (PDI) and zeta potential were found to be 131.7 nm, 0.105 and −9.29 mV respectively. Ex vivo studies revealed improved intestinal permeation of LNC. Enhancements in cytotoxicity, ROS generation and apoptosis were observed against MCF-7 cells that could be attributed to elevated intracellular drug accumulation using LNC. Pharmacokinetic studies revealed a 2.6-fold increase in the bioavailability of BOS during fasted state and a 1.36-fold increase during fed state when BOS was administered via LNC, indicating superior oral bioavailability. Cmax fast/fed was found to be 0.94 while, AUC fast/fed was 0.9258 which was close to 1, indicating attenuation of the food effect by BOS LNC. Therefore, LNCs can serve as promising delivery carriers for attenuation of food effect during breast cancer therapy.

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

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

THU549 Targeting The Growth Hormone Receptor Attenuates Tumor Exosome Mediated Propagation Of Chemoresistance In Melanoma

Abstract Disclosure: P. Kulkarni: None. R. Basu: None. T. Bonn: None. J.J. Kopchick: None. Elevated ATP-binding cassette (ABC) transporters in tumor cells resulting in decreased intracellular drug accumulation is a major reason for chemotherapy resistance in cancer. Mounting evidence indicates that extracellular vesicles (EVs), particularly exosomes, the smallest subset of EVs, play a crucial role in the spread of drug resistance. We have previously shown that growth hormone (GH) decreases therapeutic efficacy in melanoma via upregulating the levels of ABC transporters, whereas when GHR is knocked down or GH/GHR interaction is inhibited by GHR antagonist, Pegvisomant, these ABC transporters are significantly downregulated. No study has yet directly assessed the effect of GH or GHR antagonism on exosomal cargoes in terms of promoting drug resistance. We observe that human melanoma cells (Malme3M, SK-Mel28, and MDA-MB-435) when treated with GH or doxorubicin alone or in combination increase the exosomal protein levels of multiple multi-drug efflux pumps, namely ABCC1, ABCC2, ABCB1, and ABCG2. On adding Pegvisomant to these treatments, we found a significant decrease in the levels of these exosomal drug efflux pumps induced by both autocrine and endogenously added GH. Furthermore, we assessed the role of GH in exosome-mediated dissemination of chemoresistance from drug-resistant to drug-sensitive cells. When GH and doxorubicin-treated melanoma-derived exosomes were administered to treatment-naïve melanoma cells, a significant increase in drug efflux was observed in the latter, compared to the control. On the other hand, when Pegvisomant co-treated melanoma-derived exosomes were administered to treatment-naïve melanoma cells, the drug efflux was attenuated, indicating chemo-sensitization. Collectively, these observations indicate that Pegvisomant suppresses various exosomal cargoes modulating drug resistance in melanoma. Acknowledgment: This work was supported in part by the State of Ohio’s Eminent Scholar Program includes a gift from Milton and Lawrence Goll, by the AMVETS, Ohio University’s Student Enhancement Award, and Edison Biotechnology Institute. Presentation: Thursday, June 15, 2023

Pentagalloyl Glucose-Targeted Inhibition of P-Glycoprotein and Re-Sensitization of Multidrug-Resistant Leukemic Cells (K562/ADR) to Doxorubicin: In Silico and Functional Studies.

Combining phytochemicals with chemotherapeutic drugs has demonstrated the potential to surmount drug resistance. In this paper, we explore the efficacy of pentagalloyl glucose (PGG) in modulating P-gp and reversing multidrug resistance (MDR) in drug-resistant leukemic cells (K562/ADR). The cytotoxicity of PGG was evaluated using a CCK-8 assay, and cell apoptosis was assessed using flow cytometry. Western blotting was used to analyze protein expression levels. P-glycoprotein (P-gp) activity was evaluated by monitoring the kinetics of P-gp-mediated efflux of pirarubicin (THP). Finally, molecular docking, molecular dynamics simulation, and molecular mechanics with generalized Born and surface area solvation (MM-GBSA) calculation were conducted to investigate drug-protein interactions. We found that PGG selectively induced cytotoxicity in K562/ADR cells and enhanced sensitivity to doxorubicin (DOX), indicating its potential as a reversal agent. PGG reduced the expression of P-gp and its gene transcript levels. Additionally, PGG inhibited P-gp-mediated efflux and increased intracellular drug accumulation in drug-resistant cells. Molecular dynamics simulations and MM-GBSA calculation provided insights into the binding affinity of PGG to P-gp, suggesting that PGG binds tightly to both the substrate and the ATP binding sites of P-gp. These findings support the potential of PGG to target P-gp, reverse drug resistance, and enhance the efficacy of anticancer therapies.

Core-shell cisplatin/SiO2 nanocapsules combined with PTC-209 overcome chemotherapy–Acquired and intrinsic resistance in hepatocellular carcinoma

The primary cause of cisplatin resistance in liver cancer is reduced intracellular drug accumulation and altered DNA repair/apoptosis signaling. Existing strategies to reverse cisplatin resistance have limited efficacy, as they target individual factors. This study proposes a drug delivery system consisting of a cisplatin core, a silica shell with a tetra-sulfide bond, and a PEG-coated surface (Core/shell-PGCN). The system is designed to consume glutathione (GSH) and reduce cisplatin excretion from cells, thereby overcoming acquired cisplatin resistance. In addition, Core/shell-PGCN incorporates PTC-209 (Core/shell-PGCN@PTC-209), a Bmi1 inhibitor that suppresses liver cancer stem cells (CSC), to mitigate DNA repair/apoptosis signaling and reverse intrinsic cisplatin resistance. In vivo and in vitro results demonstrate that Core/shell-PGCN@PTC-209 can comprehensively regulate GSH and CSC, reverse intrinsic and acquired cisplatin resistance, and enhance the efficacy of cisplatin in treating liver cancer. This "inner cultivation, outer action" approach may offer a new strategy for reversing cisplatin resistance in liver cancer. Statement of significanceCisplatin resistance is widely observed in liver cancer (HCC) chemotherapy, with two mechanisms identified: acquired and intrinsic. Most strategies aimed at overcoming cisplatin resistance focus on a single perspective. This study introduces a core-shell drug delivery system (DDS) combined with HCC stem cell inhibitors, which can effectively address cisplatin resistance in HCC by targeting both acquisition and internality. Specifically, the core-shell drug delivery system can impede cisplatin efflux by neutralizing the acquired resistance factor (GSH), thus overcoming acquired resistance. Additionally, HCC stem cell inhibitors can reverse intrinsic resistance by inhibiting HCC stem cells. Therefore, this study contributes to the application of DDS in combating drug resistance in HCC and enhances its potential for clinical implementation.

Nanoparticle-Mediated Delivery of Satraplatin to Overcome Cisplatin Drug Resistance.

Drug resistance and cancer metastasis are the major obstacles for widely used platinum-based chemotherapy. It is acknowledgement that the decreasing intracellular accumulation of anticancer drugs and increasing sulfur-binding detoxification are two major mechanisms related to drug resistance. Herein, we developed a practical and straightforward method for formulating the clinically used anticancer drug satraplatin (JM-216) with D-α-tocopheryl polyethylene glycol succinate (TPGS)-based polymers to create satraplatin-loaded nanoparticles (SatPt-NPs). The experimental results demonstrate that SatPt-NPs exhibited comparable efficacy to A2780 in treating the A2780 cisplatin-resistant ovarian cancer cell line (A2780DDP), indicating their significant potential in overcoming drug resistance. Additionally, buthionine sulfoximine (BSO) is capable of depleting intracellular glutathione (GSH), resulting in reduced detoxification. After BSO treatment, the IC50 value of SatPt-NPs changed from 0.178 to 0.133 μM, which remained relatively unchanged compared to cisplatin. This suggests that SatPt-NPs can overcome drug resistance by evading GSH detoxification. Therefore, SatPt-NPs have the ability to inhibit drug resistance in tumor cells and hold tremendous potential in cancer treatment.

A tumor microenvironment-responsive core-shell tecto dendrimer nanoplatform for magnetic resonance imaging-guided and cuproptosis-promoted chemo-chemodynamic therapy.

Theranostic nanoplatforms for combination tumor therapy have gained lots of attention recently due to the optimized therapeutic efficiency and simultaneous diagnosis performance. Herein, a novel tumor microenvironment (TME)-responsive core-shell tecto dendrimer (CSTD) was assembled by phenylboronic acid- and mannose-modified poly(amidoamine) dendrimers via the phenylboronic ester bonds that are responsive to low pH and reactive oxygen species (ROS), and efficiently loaded with copper ions and chemotherapeutic drug disulfiram (DSF) for tumor-targeted magnetic resonance (MR) imaging and cuproptosis-promoted chemo-chemodynamic therapy. The formed CSTD-Cu(II)@DSF could be specifically taken up by MCF-7 breast cancer cells, accumulated to the tumor model after circulation, and released drugs in response to the weakly acidic TME with overexpressed ROS. The enriched intracellular Cu(II) ions could induce the oligomerization of lipoylated proteins and proteotoxic stress for cuproptosis, and lipid peroxidation for chemodynamic therapy as well. Moreover, the CSTD-Cu(II)@DSF could cause the dysfunction of mitochondria and arrest the cell cycle at the G2/M phase, leading to enhanced DSF-mediated cell apoptosis. As a result, CSTD-Cu(II)@DSF could effectively inhibit the growth of MCF-7 tumors by a combination therapy strategy integrating chemotherapy with cuproptosis and chemodynamic therapy. Lastly, the CSTD-Cu(II)@DSF also displays Cu(II)-associated r1 relaxivity, allowing for T1-weighted real-time MR imaging of tumors in vivo. The developed tumor-targeted and TME-responsive CSTD-based nanomedicine formulation may be developed for accurate diagnosis and synergistic treatment of other cancer types. STATEMENT OF SIGNIFICANCE: Constructing an effective nanoplatform for the combination of therapeutic effects and real-time tumor imaging remains a challenge. In this study, we reported for the first time an all-in-one tumor-targeted and tumor microenvironment (TME) responsive nanoplatform based on core-shell tecto dendrimer (CSTD) for the cuproptosis-promoted chemo-chemodynamic therapy and enhanced MR imaging. The efficient loading, selective tumor-targeting, and TME-responsive release of Cu(II) and disulfiram could enhance the intracellular accumulation of drugs, induce cuproptosis of cancer cells, and amplify the synergistic chemo-chemodynamic therapeutic effect, resulting in enhanced MR imaging and accelerated tumor eradication. This study sheds new light on the development of theranostic nanoplatforms for early accurate diagnosis and effective treatment of cancers.

Target Identification in Anti-Tuberculosis Drug Discovery.

Mycobacterium tuberculosis (Mtb) is the etiological agent of tuberculosis (TB), a disease that, although preventable and curable, remains a global epidemic due to the emergence of resistance and a latent form responsible for a long period of treatment. Drug discovery in TB is a challenging task due to the heterogeneity of the disease, the emergence of resistance, and uncomplete knowledge of the pathophysiology of the disease. The limited permeability of the cell wall and the presence of multiple efflux pumps remain a major barrier to achieve effective intracellular drug accumulation. While the complete genome sequence of Mtb has been determined and several potential protein targets have been validated, the lack of adequate models for in vitro and in vivo studies is a limiting factor in TB drug discovery programs. In current therapeutic regimens, less than 0.5% of bacterial proteins are targeted during the biosynthesis of the cell wall and the energetic metabolism of two of the most important processes exploited for TB chemotherapeutics. This review provides an overview on the current challenges in TB drug discovery and emerging Mtb druggable proteins, and explains how chemical probes for protein profiling enabled the identification of new targets and biomarkers, paving the way to disruptive therapeutic regimens and diagnostic tools.