Multidrug Resistance In Cancer Cells Research Articles

Evaluation of Novel Benzo-annelated 1,4-dihydropyridines as MDR Modulators in Cancer Cells.

Multidrug resistance (MDR) is the main problem in anticancer therapy today. Causative transmembrane efflux pumps in cancer cells have been reconsidered as promising anticancer target structures to restore anticancer drug sensitivity by various strategies, including MDR modulators. MDR modulators interfere with the efflux pumps and improve the cellular efficiency of chemotherapeutics. So far, only a few candidates have gone through clinical trials with disappointing results because of low specificity and toxic properties. This study aimed to find Novel MDR modulators to effectively combat multidrug resistance in cancer cells. We synthesized various novel benzo-annelated 1,4-dihydropyridines to evaluate them as MDR modulators towards ABCB1 in cancer cells. Synthesized compounds were purified by column chromatography. The MDR modulation of ABCB1 was determined in cellular efflux assays using the flow cytometry technique and cellular fluorescent measurements by the use of each fluorescent substrate. Compounds were yielded in a two-step reaction with structurally varied components. Further, substituent- dependent effects on the determined MDR inhibiting properties towards ABCB1 were discussed. Cellular studies prove that there is no toxicity or restoration of cancer cell sensitivity towards the used anticancer drug. Novel MDR modulators could be identified with favorable methoxy and ester group functions. Their use in both ABCB1 non-expressing and overexpressing cells proves a selective toxicity-increasing effect of the applied anticancer agent in the ABCB1 overexpressing cells, whereas the toxicity effect of the anticancer drug was almost unchanged in the non-expressing cells. These results qualify our novel compounds as perspective anticancer drugs compared to MDR modulators with nonselective toxicity properties.

Investigation of the effects of thiazole compounds on thioredoxin reductase 1 (TrxR1), glutathione S-transferase (GST), and glutathione reductase (GR) targeted human brain glioblastoma cancer (U-87 MG).

Cancer is a fatal disease that kills thousands of people worldwide. Despite the information produced by research on cancer treatment, applications in cancer treatment are limited. Therefore, scientists' efforts to develop more effective treatment approaches continue. In the study, we aimed to determine the anticancer potential of amino thiazole compounds on human glioblastoma (U-87 MG) and human dermal fibroblast (HDFa) cells and their inhibition effects on enzymes that cause multidrug resistance in cancer cells. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide cell viability test was performed to understand the cytotoxic properties of thiazole derivatives. The cellular death mechanisms behind thiazole application were investigated using flow cytometry analysis. According to cell viability analysis, thiazole derivatives exhibited a greater effect on U-87 MG than the HDFa cell line in terms of cytotoxicity. Flow cytometry showed higher apoptotic cell death in U-87 MG cells than in the HDFa cell line. It can be concluded that thiazole compounds exert anticancer effects on U-87 MG and HDFa as well as show apoptotic properties. Their effects on thioredoxin reductase 1 (TrxR1), glutathione S-transferase (GST), and glutathione reductase (GR) activities, which are important in the development of chemotherapeutic methods, were also examined. From the results obtained, it was determined that the 2-amino-4-(p-tolyl)thiazole (T7) compound significantly suppressed both TrxR1 and GST activities, and the 2-amino-6-methylbenzothiazole (T8) compound significantly suppressed both TrxR1 and GST activities. Compound T7 was determined to be a selective inhibitor for TrxR1 and GST targeting, and compound T8 was determined to be a selective inhibitor for TrxR1 and GR targeting glioblastoma treatment.

Reversing Anticancer Drug Resistance by Synergistic Combination of Chemotherapeutics and Membranolytic Antitumor β-Peptide Polymer.

Multidrug resistance is the main obstacle to cancer chemotherapy. Overexpression of drug efflux pumps causes excessive drug efflux from cancer cells, ultimately leading to drug resistance. Hereby, we raise an effective strategy to overcome multidrug resistance using a synergistic combination of membranolytic antitumor β-peptide polymer and chemotherapy drugs. This membrane-active β-peptide polymer promotes the transmembrane transport of chemotherapeutic drugs by increasing membrane permeability and enhances the activity of chemotherapy drugs against multidrug-resistant cancer cells. As a proof-of-concept demonstration, the synergistic combination of β-peptide polymer and doxorubicin (DOX) is substantially more effective than DOX alone against drug-resistant cancer both in vitro and in vivo. Notably, the synergistic combination maintains a potent anticancer activity after continuous use. Collectively, this combination therapy using membrane lytic β-peptide polymer appears to be an effective strategy to reverse anticancer drug resistance.

Abstract ND08: M3554, a novel anti-GD2 antibody drug conjugate

Abstract The glycosphingolipid GD2 is a cell membrane component of a limited number of normal tissues including nerve cells, melanocytes or lymphocytes. However, in some tumor types as neuroblastoma, osteosarcoma, glioma, or soft tissue sarcoma, GD2 is found on cell membranes with high levels. This tumor associated expression pattern makes GD2 an attractive target for therapeutic antibodies like dinutuximab (ch14.18) and naxitamab, which have been approved for neuroblastoma. M3554 is designed a be novel anti-GD2 ADC based on the humanized ch14.18 anti-GD2 antibody. The payload linker consists of the Topoisomerase I inhibitor (TOP1i) payload exatecan and a cleavable beta-glucuronide linker structure, which demonstrated higher potency, better bystander effects and improved activity in multidrug resistant cancer cells compared to other TOP1i payloads. While the antitumor effect of approved anti-GD2 antibodies is presumably related to Antibody-Dependent Cellular Cytotoxicity (ADCC) and Complement- Dependent Cytotoxicity (CDC), M3554 will exploit the high antigen density for direct tumor cytotoxicity by the payload. As the ADCC and CDC effector functions are believed to cause side effects for the approved GD2 antibodies, we have modified the M3554 antibody moiety with mutations in the Fc-region to reduce or eliminate these Fcγ receptor mediated functions. The cytotoxicity of M3554 was in the subnanomolar IC50 range for the GD2-positive neuroblastoma cell line CHP134. M3554 showed strong in vivo antitumor activity with tumor regressions in the CHP134 xenograft model and in patient-derived xenografts from neuroblastoma, osteosarcoma or glioma at doses ranging from 3 to 10 mg/kg. In addition, M3554 showed favorable pharmacokinetics in rats and monkeys, indicating a very stable linker-payload, and a favorable safety profile. In conclusion, M3554 represents a novel therapeutic approach for oncology indications with a high unmet medical need and high GD2 prevalence. Disclosures: Christiane Amendt, Christine Knuehl, Willem Sloot, Stanley Sweeney-Lasch, Joao NS Pereira, Julia Dotterweich, Hans-Henning Boehm and Jan Anderl are employees of the healthcare business of Merck KGaA, Darmstadt, Germany. Timothy Crandall is an employee of EMD Serono. Mira Toister-Achituv is an employee of Inter-Lab Ltd., Yavne, Israel, an affiliate of Merck KGaA, Darmstadt, Germany.Sponsor: This study was sponsored by the healthcare business of Merck KGaA, Darmstadt, Germany (CrossRef Funder ID: 10.13039/100009945). Citation Format: Christiane Amendt, Christine Knuehl, Timothy Crandall, Willem Sloot, Mira Toister-Achituv, Stanley Sweeney-Lasch, Joao NS Pereira, Julia Dotterweich, Hans_Henning Boehm, Jianguo Ma, Jan Anderl. M3554, a novel anti-GD2 antibody drug conjugate [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr ND08.

Novel hybrid compounds of sclareol and doxorubicin as potential anticancer nanotherapy for glioblastoma

Two novel hybrid compounds, CON1 and CON2, have been developed by combining sclareol (SC) and doxorubicin (DOX) into a single molecular entity. These hybrid compounds have a 1:1 molar ratio of covalently linked SC and DOX. They have demonstrated promising anticancer properties, especially in glioblastoma cells, and have also shown potential in treating multidrug-resistant (MDR) cancer cells that express the P-glycoprotein (P-gp) membrane transporter. CON1 and CON2 form nanoparticles, as confirmed by Zetasizer, transmission electron microscopy (TEM), and chemical modeling. TEM also showed that CON1 and CON2 can be found in glioblastoma cells, specifically in the cytoplasm, different organelles, nucleus, and nucleolus. To examine the anticancer properties, the U87 glioblastoma cell line, and its corresponding multidrug-resistant U87-TxR cell line, as well as patient-derived astrocytoma grade 3 cells (ASC), were used, while normal human lung fibroblasts were used to determine the selectivity. CON1 and CON2 exhibited better resistance and selectivity profiles than DOX, showing less cytotoxicity, as evidenced by real-time cell analysis, DNA damage determination, cell death induction, mitochondrial respiration, and mitochondrial membrane depolarization studies. Cell cycle analysis and the β-galactosidase activity assay suggested that glioblastoma cells die by senescence following CON1 treatment. Overall, CON1 and CON2 showed great potential as they have better anticancer features than DOX. They are promising candidates for additional preclinical and clinical studies on glioblastoma.

Abstract 4674: Reserpine analog modulates transport function of ABCG2

Abstract Backgrounds: Reserpine is an agent that is used for the treatment of hypertension. ABCG2 also known as breast cancer resistance protein (BCRP) is a member of the ABC transporters associated with multidrug resistance (MDR). Our high-throughput screening assay has revealed that reserpine analog inhibits transport function of ABCG2. Aim: To investigate the effect of reserpine analog on ABCG2 function. Results: Flow cytometry assay showed that reserpine analog blocked the efflux of Pheophorbide a (PhA: fluorescent substrate of ABCG2) from ABCG2-expressing HCT-116/BCRP colon cancer cells in a concentration-dependent manner. Furthermore, cell proliferation assay (MTS assay) revealed that 5 and 10 μM reserpine analog sensitized HCT-116/BCRP cells to SN38 with IC50 value 0.61 + 0.12 μM and 0.22 + 0.036 μM, respectively. Finally, reserpine analog did not stimulate ABCG2-mediated ATP hydrolysis, but rather inhibited it (concentration required for 50% inhibition = 2.7 μM), suggesting that reserpine analog might prevent conformational changes required for ATP hydrolysis. Conclusion: Reserpine analog could be developed as a potent modulator to overcome ABCG2-mediated MDR in cancer cells. Citation Format: Shinobu Ohnuma, Shoji Kokubo, Norihiko Sugisawa, Megumi Murakami, Yuuri Hatsuzawa, Minoru Kobayashi, Taiki Kajiwara, Hideyuki Suzuki, Hideaki Karasawa, Kazuhiro Watanabe, Takayuki Doi, Suresh V. Ambudkar, Takashi Kamei, Michiaki Unno. Reserpine analog modulates transport function of ABCG2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4674.

Abstract 5875: Upregulation of the RNA binding protein HuR by cancer-secreted exosome to mediate multidrug resistance

Abstract Background and Aim: Multidrug resistance (MDR) is an unresolved obstacle to cancer chemotherapy. It is usually caused by overexpression of drug efflux transporters including ABCG2. Exosomes are extracellular lipid vesicles released from all cells upon the fusion of multivesicular bodies with plasma membrane. Tumor-derived exosomes have been shown to mediate cell-to-cell transfer of oncogenic materials to promote drug resistance. Human antigen R (HuR) is an extensively studied RNA binding protein that regulates the stability, translation, and nucleus-to-cytoplasm shuttling of mRNAs. Numerous HuR-targeting mRNAs play crucial roles in tumorigenesis, invasion and metastasis. We have previously reported the induction of ABCG2 and MDR phenotype by HuR overexpression in colon cancer. HuR overexpression is linked with high-grade malignancy and poor prognosis in cancer patients. This study investigated the enrichment of HuR inducing microRNAs (miRNAs) in exosomes secreted from MDR colon cancer and its intracellular transfer to drive MDR. Method: Cancer exosome-mediated transfer of miRNAs from ABCG2-overexpressing resistant colon cancer cells S1M1-80 to a few sensitive colon cell lines was evaluated. Exosomes were isolated from S1M1-80 conditioned medium by differential centrifugation method. The uptake of fluorescence-labeled exosome from donor MDR cancer cells by recipient sensitive cells was visualized by fluorescence microscopy. MiRNA microarray was conducted to identify differentially expressed miRNAs in drug sensitive cells after incubation with S1M1-80-secreted exosomes. Western blot and qPCR analysis were conducted to measure HuR and ABCG2 expression. Result: Exosomes were isolated from resistant S1M1-80 cells, whose purity was confirmed by the presence of exosomal markers (Tsg101 and Alix) but absence of cellular marker (GRP78) by Western blot analysis. These exosomes reduced the apoptotic effect of SN-38 or 5-fluorouracil in sensitive colon cancer cell lines (HCT116, S1, and SW480) by inducing both HuR and ABCG2. A common upregulated miRNA (miR-155-5p) was identified by miRNA microarray in the sensitive cell lines after incubation with S1M1-80-derived exosomes. MiR-155-5p was found to induce HuR expression by promoting its translation. MiR-155-5p inhibitor was shown to reverse the upregulation of HuR in HCT116 cells after exosome incubation, which subsequently suppressed ABCG2 expression and the MDR phenotype. Furthermore, inhibition of exosome uptake by dynasore was found to prevent the induction of HuR/ABCG2, and re-sensitize the exosome-treated sensitive cells to SN38. Conclusion: MDR cells-derived exosomes may spread the drug resistance phenotype by transferring a miR-155-5p/HuR/ABCG2 regulatory machinery to sensitive cells. Inhibition of this exosomal transfer of regulatory materials may prevent the spread of MDR and sensitize cancer cells to chemotherapy. Citation Format: Kenneth K.W. To. Upregulation of the RNA binding protein HuR by cancer-secreted exosome to mediate multidrug resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5875.

Elesclomol-Copper Nanoparticles Overcome Multidrug Resistance in Cancer Cells.

Elesclomol (ES), a copper-binding ionophore, forms an ES-Cu complex with copper ions (Cu(II)). ES-Cu has been proven to induce mitochondrial oxidative stress and copper-dependent cell death (cuprotosis). However, ES-Cu is poorly water-soluble, and its delivery to various cancer cells is a challenge. Herein, we designed a d-α-tocopherol polyethylene glycol 1000 succinate/chondroitin sulfate-cholic acid (TPGS/CS-CA)-based micellar nanoparticle for delivering the ES-Cu complex to various cancer cell lines to demonstrate its efficacy as an anticancer agent. The ES-Cu nanoparticles exerted high encapsulation efficiency and excellent serum stability. The anticancer efficacy of ES-Cu nanoparticles was evaluated in various drug-sensitive cell lines (DU145, PC3, and A549) and drug-resistant cell lines (DU145TXR, PC3TXR, and A549TXR). The results showed that ES-Cu nanoparticles exerted potent anticancer activities in both drug-sensitive and drug-resistant cell lines. The Western blotting, reverse transcription quantitative polymerase chain reaction (RT-qPCR), and molecular docking results suggested that ES-Cu is not a substrate for P glycoprotein (P-gp), which is an efflux transporter potentially causing multidrug resistance (MDR) in cancer cells. ES-Cu nanoparticles could bypass P-gp without compromising their activity, indicating that they may overcome MDR in cancer cells and provide a novel therapeutic strategy. Additionally, the extracellular matrix of ES-Cu nanoparticles-pretreated drug-resistant cells could polarize Raw 264.7 macrophages into the M1 phenotype. Therefore, our TPGS/CS-CA-based ES-Cu nanoparticles provide an effective method of delivering the ES-Cu complex, a promising strategy to overcome MDR in cancer therapy with potential immune response stimulation.

The SMAC mimetic GDC-0152 is a direct ABCB1-ATPase activity modulator and BIRC5 expression suppressor in cancer cells

Upregulation of the multidrug efflux pump ABCB1/MDR1 (P-gp) and the anti-apoptotic protein BIRC5/Survivin promotes multidrug resistance in various human cancers. GDC-0152 is a DIABLO/SMAC mimetic currently being tested in patients with solid tumors. However, it is still unclear whether GDC-0152 is therapeutically applicable for patients with ABCB1-overexpressing multidrug-resistant tumors, and the molecular mechanism of action of GDC-0152 in cancer cells is still incompletely understood. In this study, we found that the potency of GDC-0152 is unaffected by the expression of ABCB1 in cancer cells. Interestingly, through in silico and in vitro analysis, we discovered that GDC-0152 directly modulates the ABCB1-ATPase activity and inhibits ABCB1 multidrug efflux activity at sub-cytotoxic concentrations (i.e., 0.25×IC50 or less). Further investigation revealed that GDC-0152 also decreases BIRC5 expression, induces mitophagy, and lowers intracellular ATP levels in cancer cells at low cytotoxic concentrations (i.e., 0.5×IC50). Co-treatment with GDC-0152 restored the sensitivity to the known ABCB1 substrates, including paclitaxel, vincristine, and YM155 in ABCB1-expressing multidrug-resistant cancer cells, and it also restored the sensitivity to tamoxifen in BIRC5-overexpressing tamoxifen-resistant breast cancer cells in vitro. Moreover, co-treatment with GDC-0152 restored and potentiated the anticancer effects of paclitaxel in ABCB1 and BIRC5 co-expressing xenograft tumors in vivo. In conclusion, GDC-0152 has the potential for use in the management of cancer patients with ABCB1 and BIRC5-related drug resistance. The findings of our study provide essential information to physicians for designing a more patient-specific GDC-0152 clinical trial program in the future.

Pluronic-coated hydroxypropyl-β-cyclodextrin nanoparticle potentiated chemotherapy on multidrug resistance cancer cells via improved docetaxel loading and P-glycoprotein inhibition

In the pharmaceutical formulation of anticancer drugs, US FDA-approved cyclodextrin (CD) and its derivates have been widely employed. Among them, hydroxypropyl β-cyclodextrin (HPCD) has attracted considerable attention owing to low toxicity, improved water solubility, and enhanced drug absorption; however, HPCD exhibits low drug loading efficiency and poor anticancer efficacy in multidrug-resistant (MDR) cancer cells. Therefore, to improve the drug loading efficiency and simultaneously overcome the MDR effects, we developed docetaxel (DTX)-loaded Pluronic®(PLU)-coated hydroxypropyl-β-cyclodextrin nanoparticles (DTX@PLU/HPCD NPs). We employed a simple nanoprecipitation technique, wherein PLU acted as a P-glycoprotein inhibitor to overcome MDR and an enhancer to achieve high drug loading. The HPCD NPs were coated with PLU (PF127, PP123, and PL81) of varying hydrophilic/lipophilic balance values, and the amount of encapsulated DTX was optimized. The DTX-loaded HPCD formulations (DTX@HPCD NP, DTX@PF127/HPCD NP, and DTX@PP123/HPCD NP) exhibited good stability and facilitated sustained release. The HPCD formulations exerted no cytotoxicity against examined cancer cell lines (HCT15 and SCC 7). DTX@PLU/HPCD NPs exerted potent anticancer effects in vitro. Notably, DTX@PP123/HPCD NPs significantly reduced the tumor volume in a mouse model. Collectively, these results indicate that PLU/HPCD NPs could function as drug carriers to alleviate toxicity and overcome MDR in various cancer models.

Structure-activity relationship of anticancer drug candidate quinones.

Breast cancer is one of the most prevalent cancer types worldwide. Chemotherapy is a substantial approach in the management of breast cancer despite the occurrence of chemotherapy-associated side effects and the development of multidrug resistance in cancer cells. At this point, a variety of quinone derivatives may represent potential as possible anticancer drug candidates due to possessing structural similarity towards clinically used anticancer drugs like doxorubicin. Therefore, we investigated the cytotoxic effects of various quinone derivatives with structural diversity towards a variety of breast cancer cells. We further determined their toxicity in healthy cells to evaluate their drug capability potential. Eighteen quinone derivatives (arbutin, hydroquinone, alkannin, lapachol, lawsone, juglone, aloe-emodin, aloin, cascaroside A (8-O-β-D-glucoside of 10-C-β-D-glucosyl aloe-emodin anthrone), chrysophanol, chrysophanol-8-O-β-D-glucoside, emodin, emodin-8-O-β-D-glucoside, frangulin A (emodin-6-O-a-L-rhamnoside), physcion, rhein, sennoside A, sennoside B (sennoside A and sennoside B are stereoisomers and rhein-dianthrone diglycosides in which β-D-glucose units are bound to the OH groups of rhein anthrones at their 8th positions) were tested on MCF-7, SK-BR-3, MDA-MB-468, and MDA-MB-231 breast cancer cells and on H9c2 healthy rat cardiac myoblast cells in terms of their cytotoxicity and toxicity, respectively. The resazurin reduction assay was used to determine the cytotoxicity. Among the tested compounds, two naphthoquinone derivatives alkannin and juglone exhibited remarkable cytotoxicity on breast cancer cells and exhibited alleviated toxicity profiles on healthy cells deserving further investigation as possible drug candidates against breast cancer. Structure-activity relationships of these compounds were also evaluated and discussed. Alkannin and juglone, which are naphthoquinone derivatives isolated from natural sources, may be promising agents in the development of drug-candidate molecules with increased efficacy and safety for breast cancer.

Process optimization for green synthesis of silver nanoparticles using Rubus discolor leaves extract and its biological activities against multi-drug resistant bacteria and cancer cells

Multi-drug resistant (MDR) bacteria are considered a serious public health threat. Also, increasing rate of resistance to anticancer drugs, as well as their toxicity, is another point of concern. Therefore, the new antibacterial and anticancer agents are always needed. The synthesizing silver nanoparticles (AgNPs) using medicinal plants, is an effective approach for developing novel antibacterial and anticancer agents. Rubus discolor, a native species of the Caucasus region, produces leaves that are typically discarded as a by-product of raspberry production. The present study has focused on optimizing the green synthesis of AgNPs using R. discolor leaves extract through response surface methodology. The optimal values for AgNPs synthesis were an AgNO3 concentration of 7.11 mM, a time of 17.83 h, a temperature of 56.51 °C, and an extract percentage of 29.22. The production of AgNPs was confirmed using UV–visible spectroscopy (λmax at 456.01 nm). TEM analysis revealed well-dispersed AgNPs (an average size of 37 nm). The XRD analysis confirmed the crystalline structure. The EDX detected a strong peak at 3 keV corresponded to Ag. The zeta potential value (− 44.2 mV) indicated the stability of nanoparticles. FT-IR spectra showed the presence of various functional groups from plant compounds, which play an important role in the capping and bio-reduction processes. The AgNPs revealed impressive antibacterial activities against MDR Escherichia coli and Pseudomonas aeruginosa (MIC ranging from 0.93 to 3.75 mg ml−1). The phytochemical analysis indicated the presence of phenolics, tannins, and flavonoids on the surface of AgNPs. They also showed significant cytotoxic effects on A431, MCF-7, and HepG2 cells (IC50 values ranging from 11 to 49.1 µg ml−l).

Foretinib, a c-MET receptor tyrosine kinase inhibitor, tackles multidrug resistance in cancer cells by inhibiting ABCB1 and ABCG2 transporters

BackgroundABC transporter-mediated multidrug resistance (MDR) remains a major obstacle for cancer pharmacological treatment. Some tyrosine kinase inhibitors (TKIs) have been shown to reverse MDR. The present study was designed to evaluate for the first time whether foretinib, a multitargeted TKI, can circumvent ABCB1 and ABCG2-mediated MDR in treatment-resistant cancer models. MethodsAccumulation of fluorescent substrates of ABCB1 and ABCG2 in ABCB1-overexpressing MES-SA/DX5 and ABCG2-overexpressing MCF-7/MX and their parenteral cells was evaluated by flow cytometry. The growth inhibitory activity of single and combination therapy of foretinib and chemotherapeutic drugs on MDR cells was examined by MTT assay. Analysis of combined interaction effects was performed using CalcuSyn software. ResultsIt was firstly proved that foretinib increased the intracellular accumulation of rhodamine 123 and mitoxantrone in MES-SA/DX5 and MCF-7/MX cancer cells, with accumulation ratios of 12 and 2.2 at 25 μM concentration, respectively. However, it did not affect the accumulation of fluorescent substrates in the parental cells. Moreover, foretinib synergistically improved the cytotoxic effects of doxorubicin and mitoxantrone. The means of combination index (CI) values at fraction affected (Fa) values of 0.5, 0.75, and 0.9 were 0.64 ± 0.08 and 0.47 ± 0.09, in MES-SA/DX5 and MCF-7/MX cancer cells, respectively. In silico analysis also suggested that the drug-binding domain of ABCB1 and ABCG2 transporters could be considered as potential target for foretinib. ConclusionOverall, our results suggest that foretinib can target MDR-linked ABCB1 and ABCG2 transporters in clinical cancer therapy.

Andrographolide reverts multidrug resistance in KBChR 8-5 cells through AKT signaling pathway.

Multidrug resistance (MDR) is a major obstacle in cancer chemotherapy. P-glycoprotein (P-gp) one of the ATP-binding cassette (ABC) transporters plays an important role in MDR. In this study, we examined the sensitizing property of andrographolide (Andro) to reverse MDR in the drug-resistant KBChR 8-5 cells. Andro exhibited increased cytotoxicity in a concentration-dependent manner in the P-gp overexpressing KBChR 8-5 cells. Furthermore, Andro showed synergistic interactions with PTX and DOX in this drug-resistant cells. Andro co-administration enhanced PTX- and DOX-induced cytotoxicity and reduced cell proliferation in the MDR cancer cells. Moreover, reactive oxygen species (ROS) were elevated with a decrease in the mitochondrial membrane potential (MMP) during Andro and chemotherapeutic drugs combination treatment in the drug-resistant cells. Furthermore, Andro and PTX-induced cell cycle arrest was observed in the drug-resistant cell. We also noticed that the expression of ABCB1 and AKT were downregulated during Andro (4 µM) treatment. Furthermore, Andro treatment enhanced the expression of caspase 3 and caspase 9 in the combinational groups that support the enhanced apoptotic cell death in drug-resistant cancer cells. Therefore, the results reveal that Andro plays a role in the reversal of P-gp-mediated MDR in KBChR 8-5 cells which might be due to regulating ABCB1/AKT signaling pathway.

ABCB1-dependent collateral sensitivity of multidrug-resistant colorectal cancer cells to the survivin inhibitor MX106-4C

AimsTo investigate the collateral sensitivity (CS) of ABCB1-positive multidrug resistant (MDR) colorectal cancer cells to the survivin inhibitor MX106–4C and the mechanism. MethodsBiochemical assays (MTT, ATPase, drug accumulation/efflux, Western blot, RT-qPCR, immunofluorescence, flow cytometry) and bioinformatic analyses (mRNA-sequencing, reversed-phase protein array) were performed to investigate the hypersensitivity of ABCB1 overexpressing colorectal cancer cells to MX106–4C and the mechanisms. Synergism assay, long-term selection, and 3D tumor spheroid test were used to evaluate the anti-cancer efficacy of MX106–4C. ResultsMX106–4C selectively killed ABCB1-positive colorectal cancer cells, which could be reversed by an ABCB1 inhibitor, knockout of ABCB1, or loss-of-function ABCB1 mutation, indicating an ABCB1 expression and function-dependent mechanism. MX106–4C's selective toxicity was associated with cell cycle arrest and apoptosis through ABCB1-dependent survivin inhibition and activation on caspases-3/7 as well as modulation on p21-CDK4/6-pRb pathway. MX106–4C had good selectivity against ABCB1-positive colorectal cancer cells and retained this in multicellular tumor spheroids. In addition, MX106–4C could exert a synergistic anti-cancer effect with doxorubicin or re-sensitize ABCB1-positive cancer cells to doxorubicin by reducing ABCB1 expression in the cell population via long-term exposure. ConclusionsMX106–4C selectively kills ABCB1-positive MDR colorectal cancer cells via a novel ABCB1-dependent survivin inhibition mechanism, providing a clue for designing CS compound as an alternative strategy to overcome ABCB1-mediated colorectal cancer MDR.

Utilizing non-coding RNA-mediated regulation of ATP binding cassette (ABC) transporters to overcome multidrug resistance to cancer chemotherapy

Multidrug resistance (MDR) is one of the primary factors that produces treatment failure in patients receiving cancer chemotherapy. MDR is a complex multifactorial phenomenon, characterized by a decrease or abrogation of the efficacy of a wide spectrum of anticancer drugs that are structurally and mechanistically distinct. The overexpression of the ATP-binding cassette (ABC) transporters, notably ABCG2 and ABCB1, are one of the primary mediators of MDR in cancer cells, which promotes the efflux of certain chemotherapeutic drugs from cancer cells, thereby decreasing or abolishing their therapeutic efficacy. A number of studies have suggested that non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), play a pivotal role in mediating the upregulation of ABC transporters in certain MDR cancer cells. This review will provide updated information about the induction of ABC transporters due to the aberrant regulation of ncRNAs in cancer cells. We will also discuss the measurement and biological profile of circulating ncRNAs in various body fluids as potential biomarkers for predicting the response of cancer patients to chemotherapy. Sequence variations, such as alternative polyadenylation of mRNA and single nucleotide polymorphism (SNPs) at miRNA target sites, which may indicate the interaction of miRNA-mediated gene regulation with genetic variations to modulate the MDR phenotype, will be reviewed. Finally, we will highlight novel strategies that could be used to modulate ncRNAs and circumvent ABC transporter-mediated MDR.

Cytotoxicity of synthesized silver nanoparticles on breast cancer cells

Breast cancers are becoming harder to treat due to the acquisition of chemo-drug resistance. In this study, silver nanoparticles (AgNPs) were synthesized using reducing agent NaBH4, where resulting nanoparticles were characterized using UV-vis spectroscopy, FTIR spectroscopy, SEM, and DLS. Cytotoxicity of synthesized AgNPs was evaluated against MCF-7, MCF-7-CR, and MDA-MB-231 using MTT assays. NaBH4-reduced AgNPs were unstable as a colloidal system, with zeta potential noted to be around -21 mV and a polydispersity index of around 15%, making them highly prone to aggregation. However, AgNPs significantly reduced the cell viability of MCF-7 breast cancer cell lines, while slight toxicity was seen in multi-drug resistant breast cancer cells MCF-7-CR and MDA-MB-231 at 10 µM.

Modular synthesis of functional libraries by accelerated SuFEx click chemistry.

Accelerated SuFEx Click Chemistry (ASCC) is a powerful method for coupling aryl and alkyl alcohols with SuFEx-compatible functional groups. With its hallmark favorable kinetics and exceptional product yields, ASCC streamlines the synthetic workflow, simplifies the purification process, and is ideally suited for discovering functional molecules. We showcase the versatility and practicality of the ASCC reaction as a tool for the late-stage derivatization of bioactive molecules and in the array synthesis of sulfonate-linked, high-potency, microtubule targeting agents (MTAs) that exhibit nanomolar anticancer activity against multidrug-resistant cancer cell lines. These findings underscore ASCC's promise as a robust platform for drug discovery.

Isolation and characterizations of multidrug-resistant human cancer cells by a biodegradable nano-sensor

Multidrug resistance (MDR) remains a significant challenge in cancer therapy, with inherent and acquired resistance distinct. While conventional drug selection processes enable the isolation of cancer cells with acquired multidrug resistance, identifying cancer cells with inherent drug resistance remains challenging. Herein, we proposed a molecular beacon (MB)-based strategy to identify and isolate the inherent MDR cancer cells. A lipid/PLGA core-shell nanoparticulate system (DNCP) was designed to deliver MB for intracellular MDR1 mRNA imaging. DNCP-MB – possess a surface potential of −8 mV and a size of 150 nm – demonstrated effective delivery of MB, remarkable selectivity towards the selected intracellular mRNA targets, and low cytotoxicity. Following DNCP transfection, fluorescence-activated cell sorting (FACS) was employed to differentiate MCF-7 cells into two distinct sub-populations: the Top 10 cells with a high level of MDR gene expression and the Bottom 10 cells with a low level of MDR gene expression, which represent inherent drug-resistant and non-drug-resistant cells, respectively. Intriguingly, we observed a positive correlation between elevated MDR1 mRNA expression and increased migration, enhanced proliferation rate, and tighter spheroid formation. Moreover, we conducted RNA sequencing analysis on the Top 10, Bottom 10, and MCF-7/ADR cells. The findings revealed a notable disparity in the gene ontology enrichment analysis of differentially expressed genes between the Top 10 and Bottom 10 cells when compared to the Bottom 10 and MCF-7/ADR cells. This novel approach provides a promising avenue for isolating inherent drug-resistant cells and holds significant potential in unraveling the mechanisms underlying inherent drug resistance.

LC-ESI QToF MS Non-Targeted Screening of Latex Extracts of Euphorbia seguieriana ssp. seguieriana Necker and Euphorbia cyparissias and Determination of Their Potential Anticancer Activity.

Euphorbia seguieriana ssp. seguieriana Necker (ES) and Euphorbia cyparissias (EC) with a habitat in the Deliblato Sands were the subject of this examination. The latexes of these so far insufficiently investigated species of the Euphorbia genus are used in traditional medicine for the treatment of wounds and warts on the skin. To determine their chemical composition, non-targeted screening of the latexes' chloroform extracts was performed using liquid chromatography coupled with quadrupole time-of-flight mass spectrometry employing an electrospray ionization source (LC-ESI QTOF MS). The analysis of the obtained results showed that the latexes of ES and EC represent rich sources of diterpenes, tentatively identified as jatrophanes, ingenanes, tiglianes, myrsinanes, premyrsinanes, and others. Examination of the anticancer activity of the ES and EC latex extracts showed that both extracts significantly inhibited the growth of the non-small cell lung carcinoma NCI-H460 and glioblastoma U87 cell lines as well as of their corresponding multi-drug resistant (MDR) cell lines, NCI-H460/R and U87-TxR. The obtained results also revealed that the ES and EC extracts inhibited the function of P-glycoprotein (P-gp) in MDR cancer cells, whose overexpression is one of the main mechanisms underlying MDR.