Design, synthesis, and bioactivity evaluation of novel indole-selenide derivatives as P-glycoprotein inhibitors against multi-drug resistance in MCF-7/ADR cell

The inhibition of P-glycoprotein (P-gp) has emerged as an intriguing strategy for circumventing multidrug resistance (MDR) in anticancer chemotherapy. In this study, we have designed and synthesized 30 indole-selenides as a new class of P-gp inhibitors based on the scaffold hopping strategy. Among them, the preferred compound H27 showed slightly stronger reversal activity (reversal fold: 271.7 vs 261.6) but weaker cytotoxicity (inhibition ratio: 33.7% vs 45.1%) than the third-generation P-gp inhibitor tariquidar on the tested MCF-7/ADR cells. Rh123 accumulation experiments and Western blot analysis demonstrated that H27 displayed excellent MDR reversal activity by dose-dependently inhibiting the efflux function of P-gp rather than its expression. Besides, UIC-2 reactivity shift assay revealed that H27 could bind to P-gp directly and induced a conformation change of P-gp. Moreover, docking study revealed that H27 matched well in the active pockets of P-gp by forming some key H-bonding interactions, arene-H interactions and hydrophobic contacts. These results suggested that H27 is worth to be a starting point for the development of novel Se-containing P-gp inhibitors for clinic use.

Discovery of benzochromene derivatives first example with dual cytotoxic activity against the resistant cancer cell MCF-7/ADR and inhibitory effect of the P-glycoprotein expression levels

A series of 1H-benzo[f]chromene moieties (4a-z) were synthesised under Ultrasonic irradiation and confirmed with spectral analyses. Derivative 4i solely possessed an X-ray single crystal. The anti-proliferative efficacy of the desired molecules has been explored against three cancer cells: MCF-7, HCT-116, and HepG-2 with the cytotoxically active derivatives screened against MCF-7/ADR and normal cells HFL-1 and WI-38. Furthermore, compounds 4b-d, 4k, 4n, 4q, and 4w, which possessed good potency against MCF-7/ADR, were tested as permeability glycoprotein (P-glycoprotein [P-gp]) expression inhibitors. The attained data confirmed that 4b-d, 4q, and 4w exhibited strong expression inhibition against the P-gp alongside its cytotoxic effect on MCF-7/ADR. The western blot results and Rho123 accumulation assays showed that compounds 4b-d, 4q, and 4w effectively inhibited the P-gp expression and efflux function. Meanwhile, 4b-d, 4q, and 4w induced apoptosis and accumulation of the treated MCF-7/ADR cells in the G1 phase and 4k and 4n in the S phase of the cell cycle.

Discovery of 2,5-disubstituted furan derivatives featuring a benzamide motif for overcoming P-glycoprotein mediated multidrug resistance in MCF-7/ADR cell

P-glycoprotein (P-gp) is one of the drug efflux transporters that triggers multidrug resistance (MDR) in cells. Herein, by utilizing the strategies of active skeleton splicing and structural optimization on the lead compound 5 m, a total of 50 novel 2,5-disubstituted furan derivatives were designed, synthesized, and screened for P-gp inhibitory activity. The structure-activity relationship analysis enabled the identification of an important pharmacophore N-phenylbenzamide, which resulted in the discovery of a promising drug lead compound Ⅲ-8. Ⅲ-8 possesses broad-spectrum reversal activity and low toxicity in MCF-7/ADR cells. Western blot and Rh123 accumulation assay demonstrated that Ⅲ-8 displayed the reversal activity by inhibiting P-gp efflux. Molecular docking analysis indicated a potent affinity of Ⅲ-8 to P-gp by forming H-bond interactions with residues Asn 721 and Met 986. Ⅲ-8 was determined to be a highly effective and safe P-gp inhibitor in an MCF-7/ADR xenograft mouse model.

Design, synthesis and biological evaluation of novel phenylfuran-bisamide derivatives as P-glycoprotein inhibitors against multidrug resistance in MCF-7/ADR cell

The co-administration of anticancer drugs and P-glycoprotein (P-gp) inhibitors was a treatment strategy to surmount multidrug resistance (MDR) in anticancer chemotherapy. In this study, novel phenylfuran-bisamide derivatives were designed as P-gp inhibitors based on target-based drug design, and 31 novel compounds were synthesized and screened on MCF-7/ADR cells. The result of bioassay revealed that compound y12d exhibited low cytotoxicity and promising MDR reversal activity (IC₅₀ = 0.0320 μM, reversal fold = 1163.0), 3.64-fold better than third-generation P-gp inhibitor tariquidar (IC₅₀ = 0.1165 μM, reversal fold = 319.3). The results of Western blot and rhodamine 123 accumulation verified that compound y12d exhibited excellent MDR reversal activity by inhibiting the efflux function of P-gp but not expression. Furthermore, molecular docking showed that compound y12d bound to target P-gp by forming the double H-bond interactions with residue Gln 725. These results suggest that compound y12d might be a potential MDR reveal agent acting as a P-gp inhibitor in clinical therapeutics, and provide insight into design strategy and skeleton optimization for the development of P-gp inhibitors.

Synthesis of 9-Hydroxy-1H-Benzo[f]chromene Derivatives with Effective Cytotoxic Activity on MCF7/ADR, P-Glycoprotein Inhibitors, Cell Cycle Arrest and Apoptosis Effects

β-Enaminonitriles bearing 9-hydroxy-1H-benzo[f]chromene moiety was synthesized. The targeted compounds were evaluated for their anti-proliferative activity against three human tumor cell lines, PC-3, SKOV-3 and HeLa, and the active cytotoxic compounds were further evaluated against cancer cells, MCF-7/ADR, and two normal cell lines, HFL-1 and WI-38. Few compounds were assigned to be the most potent derivatives against PC-3, SKOV-3 and HeLa cell lines in comparison with Vinblastine and Doxorubicin. Several compounds possessed a relatively good potency against MCF-7/ADR cells as compared with Doxorubicin and were tested as a P-gp inhibitor. Moreover, the halogenated substituents, 2,4-F₂, 2,3-Cl₂, 2,5-Cl₂ and 3,4-Cl_2; have good potency against P-gp-mediated MDR in MCF-7/ADR as compared with Doxorubicin. Meanwhile, Rho123 accumulation assays revealed that few compounds effectively inhibited P-pg and efflux function. In addition, certain derivatives induced apoptosis and an accumulation of the treated MCF-7/ADR cells in the G1, S and G1/S phases.

Design, synthesis and bioactivity study on 5-phenylfuran derivatives as potent reversal agents against P-glycoprotein-mediated multidrug resistance in MCF-7/ADR cell

P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) is a phenomenon in which cells become resistant to structurally and mechanistically unrelated drugs resulting in low intracellular drug concentrations. It is one of the noteworthy problems in malignant tumor clinical therapeutics. So P-gp protein is one of the ideal targets to solve MDR. Based on the lead compound 5m obtained from our previous work, a series of furan derivatives featuring alkyl-substituted phenols and 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline were designed and synthesized as reversal agents against P-gp in this paper. Compound 16 containing isopropoxy possessed good potency against P-gp mediated MDR in MCF-7/ADR (IC₅₀ (doxorubicin) = 0.73 μM, RF = 69.6 with 5 μM 16 treated). Western blot results and Rh123 accumulation assays showed that 16 effectively inhibited P-gp efflux function but not its expression. The preliminary structure-activity relationship and docking studies demonstrated that compound 16 would be a potential P-gp inhibitor. Most worthy of mention is that compound 16 has achieved satisfactory results in combination with a variety of anti-tumor drugs, such as doxorubicin, paclitaxel, and vincristine. This study forwards a hopeful P-gp inhibitor for withstanding malignant tumor cell with multidrug resistance setting the basis for further studies.

Reversal of Multidrug Resistance by Apolipoprotein A1-Modified Doxorubicin Liposome for Breast Cancer Treatment

Multidrug resistance (MDR) remains a major problem in cancer therapy and is characterized by the overexpression of p-glycoprotein (P-gp) efflux pump, upregulation of anti-apoptotic proteins or downregulation of pro-apoptotic proteins. In this study, an Apolipoprotein A1 (ApoA1)-modified cationic liposome containing a synthetic cationic lipid and cholesterol was developed for the delivery of a small-molecule chemotherapeutic drug, doxorubicin (Dox) to treat MDR tumor. The liposome-modified by ApoA1 was found to promote drug uptake and elicit better therapeutic effects than free Dox and liposome in MCF-7/ADR cells. Further, loading Dox into the present ApoA1-liposome systems enabled a burst release at the tumor location, resulting in enhanced anti-tumor effects and reduced off-target effects. More importantly, ApoA1-lip/Dox caused fewer adverse effects on cardiac function and other organs in 4T1 subcutaneous xenograft models. These features indicate that the designed liposomes represent a promising strategy for the reversal of MDR in cancer treatment.

Teratogenic jervine increases the activity of doxorubicin in MCF-7/ADR cells by inhibiting ABCB1

Jervine is a natural teratogenic compound isolated from Veratrum californicum. In this study, for the first time, we revealed a novel activity of jervine in sensitizing the anti-proliferation effect of doxorubicin (DOX). We demonstrated that the synergistic mechanism was related to the intracellular accumulation of DOX via modulating ABCB1 transportation. Jervine did not affect the expression of ABCB1 in mRNA nor protein levels. However, jervine increased the ATPase activity of ABCB1 and possibly served as a substrate of ABCB1. The molecular docking results indicated that jervine was bound to a closed ABCB1 conformation and blocked drug entrance to the central binding site at the transmembrane domain. The present study identifies jervine acts as a substrate of ABCB1, and has potential to be developed as a novel and potent chemotherapy sensitizer used for patients developing multidrug resistance.

Increased NHE1 expression is targeted by specific inhibitor cariporide to sensitize resistant breast cancer cells to doxorubicin in vitro and in vivo

Background

The Na⁺/H⁺ exchanger (NHE1) plays a crucial role in cancer cell proliferation and metastasis. However, the mechanism underlying chemotherapeutic resistance in cancer cells has not been completely elucidated. The NHE1 inhibitor cariporide has been demonstrated to inhibit human cancer cell lines. The goal of this study was to provide new sights into improved cancer cell chemosensitivity mediated by cariporide with activation of the apoptosis pathway.

Methods

The NHE1 expression levels were first evaluated using the online database Oncomine and were determined by RT-PCR and western blot in vitro and in vivo. Cell proliferation was assessed In vitro through a CCK-8 assay, and apoptosis was analyzed by flow cytometry. An in vivo analysis was performed in BALB/c nude mice, which were intraperitoneally injected with MCF-7/ADR cells.

Results

NHE1 levels were significantly higher in breast cancer tissue than adjacent tissue, as well as in resistant cancer cells compared to sensitive cells. Cariporide induced the apoptosis of MCF-7/ADR cells and was associated with the intracellular accumulation of doxorubicin and G0/G1 cell cycle arrest. Moreover, cariporide decreased MDR1 expression and activated cleaved caspase-3 and caspase-9, promoting caspase-independent apoptosis in vitro. In vivo, cariporide significantly improved doxorubicin sensitivity in a xenograft model, enhancing tumor growth attenuation and diminishing tumor volume.

Conclusions

Our results demonstrate that cariporide significantly facilitates the sensitivity of breast cancer to doxorubicin both in vitro and in vivo. This finding suggests that NHE1 may be a novel adjuvant therapeutic candidate for the treatment of resistant breast cancer.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5397-7) contains supplementary material, which is available to authorized users.

Barbigerone reverses multidrug resistance in breast MCF-7/ADR cells

Development of agents to overcome multidrug resistance (MDR) is one of the important strategies in cancer chemotherapy, and P-glycoprotein (P-gp) correlates with the degree of resistance. As a naturally occurring isoflavone, whether barbigerone (BA) could reverse MDR, is unknown. In this paper, we evaluated effects of BA on reversing P-gp mediated MDR of adriamycin (ADR)-resistant human breast carcinoma (MCF-7/ADR) cells. BA (0.5 μM) treatment showed strong potency to increase ADR cytotoxicity toward MCF-7/ADR cells. It was also demonstrated that BA time- and dose-dependently increased accumulations of ADR and reduced the efflux in MCF-7/ADR cells, pretreatment of these cells with BA might relocalized ADR to the nuclei. Furthermore, the results also revealed that BA did not affect P-gp, but alter P-gp ATPase activity. Intravenous administration of BA significantly increased anticancer efficacy of ADR to MCF-7/ADR xenograft model in nude mice. These results revealed that BA might reverse P-gp mediated MDR through inhibition of ATPase activity, which indicated a novel use of BA as a potent candidate for cancer chemotherapy.

Matrine reversed multidrug resistance of breast cancer MCF-7/ADR cells through PI3K/AKT signaling pathway

Matrine is an alkaloid extracted from a Chinese herb Sophora flavescens Ait, and has been used clinically for breast cancer with marked therapeutic efficacy in China. However, the mechanism has not been well known. Thus, the present study was to explore whether Matrine reverses multidrug resistance for breast cancer cells through the regulation of PI3K/AKT signaling pathway. Methyl thiazolyl tetrazolium (MTT) assay was used to detect the inhibitory action; Annexin V to detect apoptosis; fluorospectrophotometry to examine intracellular adriamycin (ADR) accumulation; and Western blot to label the proteins of P-glycoprotein (P-gp), MRP1, PTEN, p-AKT, Bcl-2, Bax, and Caspase-3. Matrine (0-2.5 mg/mL) inhibited MCF-7/ADR cell growth and induced apoptosis (P < 0.01). A total of 0.2 mg/mL Matrine could increase the intracellular concentration of ADR; the accumulation in MCF-7/ADR cells increased 3.56 times. Compared with control group, 0.6, 1.2 mg/mL Matrine reduced protein expressions of P-gp, MRP1, p-AKT, Bcl-2, but increased PTEN, Bax, and cleaved caspase-3 gradually, and unchanged caspase-3. Matrine was more likely to reduce the expression of P-gp, MRP1, and p-AKT at the same inhibition radio of Matrine, (0.6 mg/mL) and MK2206 (0.05 μmol/L). Matrine inhibited MCF-7/ADR cell growth, induced apoptosis, and reversed multidrug resistance for breast cancer cells through the regulation of downstream apoptosis factors of PI3K/AKT signaling pathway by decreasing cell phosphorylation of AKT level.

Downregulation of eIF4G by microRNA-503 enhances drug sensitivity of MCF-7/ADR cells through suppressing the expression of ABC transport proteins

Overexpression of adenosine triphosphate-binding cassette (ABC) transport protein is emerging as a critical contributor to anticancer drug resistance. The eukaryotic translation initiation factor (eIF) 4F complex, the key modulator of mRNA translation, is regulated by the phosphoinositide 3-kinase-AKT-mammalian target of rapamycin pathway in anticancer drug-resistant tumors. The present study demonstrated the roles of ABC translation protein alterations in the acquisition of the Adriamycin (ADM)-resistant phenotype of MCF-7 human breast cells. Quantitative polymerase chain reaction and western blot analysis were applied to examine the differences in mRNA and protein levels, respectively. It was found that the expression of the ABC sub-family B member 1, ABC sub-family C member 1 and ABC sub-family G member 2 transport proteins were upregulated in MCF-7/ADR cells. An MTT assay was used to detect the cell viability, from the results MCF-7/ADR cells were less sensitive to ADM, tamoxifen (TAM) and taxol (TAX) treatment compared with MCF-7 cells. We predicted that the 3′-untranslated region of eukaryotic translation initiation factor 4-γ 1 (eIF4G) contains a potential miRNA binding site for microRNA (miR)-503 through using computational programs. These binding sites were confirmed by luciferase reporter assays. eIF4G mRNA degradation was accelerated in cells transfected with miR-503 mimics. Furthermore, it was demonstrated that eIF4G and ABC translation proteins were significantly downregulated in MCF-7/ADR cells after transfection with miR-503. It was found that miR-503 mimics could sensitize the cells to treatment with ADM, TAM and TAX. These findings demonstrated for the first time that eIF4G acted as a key factor in MCF-7/ADR cells, and may be an efficient agent for preventing and reversing multi-drug resistance in breast cancer.

Saikosaponin A, an active glycoside from Radix bupleuri, reverses P-glycoprotein-mediated multidrug resistance in MCF-7/ADR cells and HepG2/ADM cells

1. The expression and function of P-glycoprotein (P-gp) is associated with the phenotype of multidrug resistance (MDR). Saikosaponin A (SSA) is a triterpenoid saponin isolated from Radix Bupleuri. This study was mainly designed to understand effects of SSA on MDR in MCF-7/ADR and HepG2/ADM cells. 2. MDR reversal was examined as the alteration of cytotoxic drugs IC50 in resistant cells in the presence of SSA by MTT assay, and was compared with the non-resistant cells. Apoptosis and uptake of P-gp substrates in the tumor cells were detected by flow cytometry. Western blot was performed to assay the expression of P-gp. 3. Our results demonstrate SSA could increase the chemosensitivity of P-gp overexpressing HepG2/ADM and MCF-7/ADR cells to doxorubicin (DOX), vincristine (VCR) and paclitaxel. SSA promoted apoptosis of MCF-7/ADR cells in the presence of DOX. Moreover, it could also increase the retention of P-gp substrates DOX and rhodamine 123 in MCF-7/ADR cells, and decrease digoxin efflux ratio in Caco-2 cell monolayer. Finally, a mechanistic study showed that SSA reduced P-gp expression without affecting hydrolytic activity of P-gp. 4. In conclusion, our findings suggest that SSA could be further developed for sensitizing resistant cancer cells and used as an adjuvant therapy together with anticancer drugs to improve their therapeutic efficacies.

Isocyclopamine, a novel synthetic derivative of cyclopamine, reverts doxorubicin resistance in MCF-7/ADR cells by increasing intracellular doxorubicin accumulation and downregulating breast cancer stem-like cells

Cyclopamine (CPM) showed promise as a human cancer chemotherapy agent. However, limitations such as stomach acid instability and low solubility impair its clinical application. In this study, we synthesized a novel CPM analogue, isocyclopamine (ICPM), which had comparative bioactivity with CPM and improved stability and solubility. ICPM reversed doxorubicin resistance and had potent synergy with doxorubicin in MCF-7/ADR cells. We further demonstrated that the synergistic mechanism was related to the increased intracellular accumulation of doxorubicin in the cells and the downregulation of the cancer stem-like cells via modulation on both ABCB1 and ABCG2 transporters with independence of Smoothened. The present study identified ICPM as a novel derivative of CPM with better stability and solubility, which provided a useful tool for the biological and medicinal studies, as well as a novel agent for the development of new cancer chemotherapy with improved efficacy.

TPGS/Phospholipids Mixed Micelles for Delivery of Icariside II to Multidrug-Resistant Breast Cancer

The biggest challenge for the treatment of multidrug resistant cancer is to deliver a high concentration of anticancer drugs to cancer cells. Icariside II is a flavonoid from Epimedium koreanum Nakai with remarkable anticancer properties, but poor solubility and significant efflux from cancer cells limited its clinical use. In our previous study, a self-assembled mixture of micelles (TPGS-Icariside II-phospholipid complex) was successfully constructed, which could substantially increase the solubility of Icariside II and inhibit the efflux on Caco-2 cells. In this study, we evaluate the anticancer effect of the mixed micelles encapsulating Icariside II (Icar-MC) on MCF-7/ADR, a multidrug-resistant breast cancer cell line. The cellular uptake of the micelles was confirmed by fluorescent coumarin-6-loaded micelles. The IC50 of Icar-MC in MCF-7/ADR was 2-fold less than the free drug. The in vitro study showed Icar-MC induced more apoptosis and lactate dehydrogenase release. Intravenous injection of Icar-MC into nude mice bearing MCF-7/ADR xenograft resulted in a better antitumor efficacy compared with the administration of free drug, without causing significant body weight changes in mice. The antitumor effect was further verified by magnetic resonance imaging and immunohistochemical assays for Ki-67, a proliferative indicator. Moreover, Icar-MC treatment also elevated Bax/Bcl-2 ratio and the expressions of cleaved caspase-3, -8, -9 and AIFM1 in tumors. This study suggests that phospholipid/TPGS mixed micelles might be a suitable drug delivery system for Icariside II to treat multidrug resistant breast cancer.

S1 kills MCF-7/ADR cells more than MCF-7 cells: A protective mechanism of endoplasmic reticulum stress

Drug resistance in chemotherapy for breast cancer is associated with high levels of P-glycoprotein (P-gp) as well as endoplasmic reticulum (ER) stress. In this paper, we aimed to evaluate the efficacy of a pan-BH3 mimetic S1 on drug-resistant MCF-7/ADR cells, and the roles of S1-induced ER stress in cell death. S1 exhibited greater and faster mitochondrial apoptosis in MCF-7/ADR cells than in MCF-7 cells. We demonstrated by Bax/Bak activation and cyrochrome c release that the p-glycprotein had little influence on S1 entering cells and hitting its targets in MCF-7/ADR cells. An IRE1-mediated ER stress response followed by c-Jun N-terminal kinase (JNK) and extracellular signal-regulated protein kinase (ERK) activation was specifically induced by S1 in MCF-7 cells, but not in MCF-7/ADR cells. Coimmunoprecipitation and western blotting analysis determined that ER stress played a protective role in S1-induced apoptosis by triggering Bcl-2 phosphorylation, which grabbed more pro-apoptotic proteins. The synergism effect of ERK inhibitor PD98059 with S1 confirmed the protective role of ER stress. Defective ER stress in MCF-7/ADR cells confers the more sensitivity toward S1.