Multidrug Resistance In Human Cancer Cells Research Articles

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.

Retracted: Costunolide Inhibits the Growth of OAW42-A Multidrug-Resistant Human Ovarian Cancer Cells by Activating Apoptotic and Autophagic Pathways, Production of Reactive Oxygen Species (ROS), Cleaved Caspase-3 and Cleaved Caspase-9.

On Authors request due to not being able to reproduce the experiment. Reference: Yichen Fang, Jie Li, Yinan Wu, Jing Gui, Yang Shen. Costunolide Inhibits the Growth of OAW42-A Multidrug-Resistant Human Ovarian Cancer Cells by Activating Apoptotic and Autophagic Pathways, Production of Reactive Oxygen Species (ROS), Cleaved Caspase-3 and Cleaved Caspase-9. Med Sci Monit, 2019; 25: 3231-3237. DOI: 10.12659/MSM.914029.

Establishment and Characterization of a Novel Multidrug Resistant Human Ovarian Cancer Cell Line With Heterogenous MRP7 Overexpression.

Ovarian cancer is one of the leading female malignancies which accounts for the highest mortality rate among gynecologic cancers. Surgical cytoreduction followed by chemotherapy is the mainstay of treatment. However, patients with recurrent ovarian cancer are likely to exhibit resistance to chemotherapy due to reduced sensitivity to chemotherapeutic drugs. Adenosine triphosphate (ATP)-binding cassette (ABC) transporters have been extensively studied as multidrug resistance (MDR) mediators since they are responsible for the efflux of various anticancer drugs. Multidrug resistance protein 7 (MRP7, or ABCC10) was discovered in 2001 and revealed to transport chemotherapeutic drugs. Till now, only limited knowledge was obtained regarding its roles in ovarian cancer. In this study, we established an MRP7-overexpressing ovarian cancer cell line SKOV3/MRP7 via transfecting recombinant MRP7 plasmids. The SKOV3/MRP7 cell line was resistant to multiple anticancer drugs including paclitaxel, docetaxel, vincristine and vinorelbine with a maximum of 8-fold resistance. Biological function of MRP7 protein was further determined by efflux-accumulation assays. Additionally, MTT results showed that the drug resistance of the SKOV3/MRP7 cells was reversed by cepharanthine, a known inhibitor of MRP7. Moreover, we also found that the overexpression of MRP7 enhanced the migration and epithelial-mesenchymal transition (EMT) induction. In conclusion, we established an in vitro model of MDR in ovarian cancer and suggested MRP7 overexpression as the leading mechanism of chemoresistance in this cell line. Our results demonstrated the potential relationship between MRP7 and ovarian cancer MDR.

Decrease of ABCB1 protein expression and increase of G1 phase arrest induced by oleanolic acid in human multidrug-resistant cancer cells.

Oleanolic acid (OA) is a natural compound that can be found in a number of edible and medicinal plants and confers diverse biological actions. However, the direct target of OA in human tumor cells remains poorly understood, preventing its application in clinical and health settings. A previous study revealed that overexpression of caveolin-1 in human leukemia HL-60 cells can increase its sensitivity to OA. The present study aimed to investigate the effects of OA on the doxorubicin-resistant human breast cancer MCF-7 cell line (MCF-7/DOX), harringtonine-resistant human leukemia HL-60 cells (HL-60/HAR) and their corresponding parental cell lines. Western blotting was performed to measure protein expression levels, whilst Cell Counting Kit-8 (CCK-8) assays, cell cycle analysis (by flow cytometry) and apoptosis assays (with Annexin V/PI staining) were used to assess drug sensitivity. CCK-8 assay results suggested that MCF-7/DOX cells, which overexpress the caveolin-1 protein, have similar OA susceptibility to their parent line. In addition, sensitivity of MCF-7/DOX cells to OA was not augmented by knocking down caveolin-1 using RNA interference. HL-60/HAR cells exhibited a four-fold increased sensitivity to OA compared with that in their parental HL-60 cells according to CCK-8 assay. Both of the resistant cell lines exhibited higher numbers of cells at G1 phase arrest compared with those in their parent lines, as measured via flow cytometry. Treatment of both MCF-7 cell lines with 100 µM OA for 48 h induced apoptosis, with increased effects observed in resistant cells. However, no PARP-1 or caspase-3 cleavage was observed, with some positive Annexin V staining found after HL-60/HAR cells were treated with OA, suggesting that cell death occurred via non-classical apoptosis or through other cell death pathways. It was found that OA was not a substrate of ATP-binding cassette subfamily B member 1 (ABCB1) in drug-resistant cells, as indicated by the accumulation of rhodamine 123 assessed using flow cytometry. However, protein expression of ABCB1 in both of the resistant cell lines was significantly decreased after treatment with OA in a concentration-dependent manner. Collectively, these results suggest that OA could reduce ABCB1 protein expression and induce G1 phase arrest in multidrug-resistant cancer cells. These findings highlight the potential of OA for cancer therapy.

Indole Curcumin Reverses Multidrug Resistance by Reducing the Expression of ABCB1 and COX2 in Induced Multidrug Resistant Human Lung Cancer Cells

Background: Drug resistance by the cancer cells towards current chemotherapeutic approaches poses a great challenge. In the present study, an indole analogue of a well-known plant derived anticancer molecule, curcumin, was tested for its Multidrug Resistance (MDR) reversing potential in induced multi drug resistant A549 cell line. Materials and Methods: Human lung cancer cell line A549 was made Multidrug Resistant (MDR) by prolonged treatment with low dosage of Docetaxel, an established anticancer drug. The MDR induction was confirmed by morphological evidence, Hoechst 33342 staining, MTT assay, Rhodamine123 staining and RT-PCR of ABCB1 gene. Protein expression studies were carried out using western blotting technique Results and Discussions: The induced MDR A549 cells exhibited significant increase in the gene expression of ABCB1 gene at the transcriptional level. Retention and efflux studies with Pglycoprotein (P-gp) substrate Rh123 indicated that indole curcumin inhibited P-gp mediated efflux of Rhodamine. Furthermore, treatment of MDR A549 cells with indole curcumin showed downregulation of gene expression of ABCB1 and COX 2. This was also confirmed from the decreased protein expression of COX 2. Conclusion: The results of the present study indicate that indole curcumin reverses multi drug resistance by downregulating the expression of ABCB1 and COX 2 genes. Thus, indole curcumin may act as a potent modulator for ABCB1 and COX 2 mediated MDR in lung cancer.

Licochalcone A Selectively Resensitizes ABCG2-Overexpressing Multidrug-Resistant Cancer Cells to Chemotherapeutic Drugs.

The overexpression of the ATP-binding cassette (ABC) transporter ABCG2 has been linked to clinical multidrug resistance in solid tumors and blood cancers, which remains a significant obstacle to successful cancer chemotherapy. For years, the potential modulatory effect of bioactive compounds derived from natural sources on ABCG2-mediated multidrug resistance has been investigated, as they are inherently well tolerated and offer a broad range of chemical scaffolds. Licochalcone A (LCA), a natural chalcone isolated from the root of Glycyrrhiza inflata, is known to possess a broad spectrum of biological and pharmacological activities, including pro-apoptotic and antiproliferative effects in various cancer cell lines. In this study, the chemosensitization effect of LCA was examined in ABCG2-overexpressing multidrug-resistant cancer cells. Experimental data demonstrated that LCA inhibits the drug transport function of ABCG2 and reverses ABCG2-mediated multidrug resistance in human multidrug-resistant cancer cell lines in a concentration-dependent manner. Results of LCA-stimulated ABCG2 ATPase activity and the in silico docking analysis of LCA to the inward-open conformation of human ABCG2 suggest that LCA binds ABCG2 in the transmembrane substrate-binding pocket. This study provides evidence that LCA should be further evaluated as a modulator of ABCG2 in drug combination therapy trials against ABCG2-expressing drug-resistant tumors.

Optimizing Protein Function for Screening of Novel Inhibitors that Target Multi‐Drug Resistance in Cancers

P‐glycoprotein (P‐gp) belongs to the ATP‐Binding Cassette (ABC) transporter family of proteins and is strongly linked with multidrug resistance (MDR) in tumors where overexpression often abolishes the effects of chemotherapeutics by removing the therapeutics from the cells. In hopes of creating co‐therapeutics to re‐sensitize tumors to chemotherapeutics, we previously used high‐throughput in silico ligand docking studies and identified drug‐like compounds that reversed MDR in human cancer cells in culture. To evaluate the mechanism of inhibition in human P‐gp, we have isolated human P‐gp from the yeast Pichia pastoris using mixed detergent micelles. In order to effectively assess the potential inhibitors, we must be able to sufficiently stimulate our protein and have a high enough activity to see the inhibitory effects of the potential inhibitors. In previous work, we found that the activity of P‐gp assembled into membrane nanodiscs had significantly higher basal activity in the absence of transport substrate than P‐gp in detergent micelles. However, significant increase in activity in the presence of the substrate verapamil was not observed in micelles or nanodiscs. Here, we report methods of protein purification and nanodisc assembly modified to have optimally functional human P‐gp. The resulting purified P‐gp will be used to evaluate the inhibition mechanism of lead compounds that were shown to reverse MDR in cancer cell culture.Support or Funding InformationThis work was supported by NIH NIGMS [R15GM094771‐02] to PDV and JGW, SMU Hamilton Undergraduate Research Scholars and Undergraduate Research Assistantship Programs, the SMU Center for Drug Discovery, Design and Delivery, the Communities Foundation of Texas, and private gifts from Ms. Suzy Ruff of Dallas, Texas, and Ms. Myra Williams, Ph.D. of Naples, Florida. The authors would like to thank Dr. Ina L. Urbatsch, Texas Tech University Health Science Center, for providing the P. pastoris cells expressing the human wild‐type MDR1 used in this work.

Aged garlic extract and its constituent, S-allyl-L-cysteine, induce the apoptosis of neuroblastoma cancer cells due to mitochondrial membrane depolarization.

Aged garlic extract (AGE) has been demonstrated to have therapeutic properties in tumors; however its mechanisms of action have not yet been fully elucidated. A previous study revealed that AGE exerts an anti-proliferative effect on a panel of both sensitive [wild-type (WT)] and multidrug-resistant (MDR) human cancer cells. Following treatment of the cells with AGE, cytofluorimetric analysis revealed the occurrence of dose-dependent mitochondrial membrane depolarization (MMD). In this study, in order to further clarify the mechanisms of action of AGE, the effects of AGE on mitochondria isolated from rat liver mitochondria (RLM) were also examined. AGE induced an effect on the components of the electrochemical gradient (ΔµH+), mitochondrial membrane potential (ΔΨm) and mitochondrial electrochemical gradient (ΔpHm). The mitochondrial membrane dysfunctions of RLM induced by AGE, namely the decrease in both membrane potential and chemical gradient were associated with a higher oxidation of both the endogenous glutathione and pyridine nucleotide content. To confirm the anti-proliferative effects of AGE, experiments were performed on the human neuroblastoma (NB) cancer cells, SJ-N-KP and the MYCN-amplified IMR5 cells, using its derivative S-allyl-L-cysteine (SAC), with the aim of providing evidence of the anticancer activity of this compound and its possible molecular mechanism as regards the induction of cytotoxicity. Following treatment of the cells with SAC at 20 mM, cell viability was determined by MTT assay and apoptosis was detected by flow cytometry, using Annexin V-FITC labeling. The percentages of cells undergoing apoptosis was found to be 48.0% in the SJ-N-KP and 50.1% in the IMR5 cells. By cytofluorimetric analysis, it was suggested that the target of SAC are the mitochondria. Mitochondrial activity was examined by labeling the cells with the probe, 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylimidacarbocyanine iodide (JC-1). Following treatment with SAC at 50 mM, both NB cell lines exhibited a marked increase in MMD. On the whole, the findings of this study indicate that both natural products, AGE and SAC, cause cytotoxicity to tumor cells via the induction of mitochondrial permeability transition (MPT).

Costunolide Inhibits the Growth of OAW42-A Multidrug-Resistant Human Ovarian Cancer Cells by Activating Apoptotic and Autophagic Pathways, Production of Reactive Oxygen Species (ROS), Cleaved Caspase-3 and Cleaved Caspase-9.

BackgroundWorldwide, ovarian cancer has a high mortality rate due to the difficulty in diagnosing early-stage disease and resistance to chemotherapy agents. Costunolide is a plant-derived sesquiterpene lactone with anti-oxidant properties. This study aimed to investigate the effects of costunolide on cell growth, apoptosis, autophagy, the production of reactive oxygen species (ROS), cleaved caspase-3, and cleaved caspase-9 on the multidrug-resistant ovarian cancer cell line, OAW42-A.Material/MethodsThe MTT assay determined the proliferation rate of OAW42-A multidrug-resistant ovarian cancer cells and the apoptosis rate was determined using propidium iodide (PI) staining. Autophagy was detected by measuring the expression of LC3 II. Fluorescence flow cytometry was used to measure the levels of reactive oxygen species (ROS) and the mitochondrial membrane potential. Protein expression of LC3 II, beclin 1, cleaved caspase-3, and cleaved caspase-9 were measured by Western blot.ResultsCostunolide treatment inhibited the growth of OAW42-A cells with an IC50 of 25 μM, resulted in apoptotic cell death, increased the expression of Bax, and decreased the expression of Bcl-2. Confocal electron microscopy showed that costunolide induced autophagy in the OAW42-A cells. Western blot showed that costunolide treatment of OAW42-A cells increased the expression of the LC3 II, beclin 1, cleaved caspase-3, and cleaved caspase-9. Costunolide treatment significantly increased the levels of ROS and reduced the OAW42-A cell mitochondrial membrane potential.ConclusionsCostunolide inhibited growth, apoptosis, ROS generation, and was associated with loss of mitochondrial membrane potential of OAW42-A multidrug-resistant ovarian cancer cells.

Assessing Lipid Activation of Human P‐Glycoprotein for ATP Hydrolysis Analyses in the Presence of Novel Inhibitors

P‐glycoprotein (P‐gp) belongs to the ATP‐Binding Cassette (ABC) transporter family of protein. This class of membrane proteins is strongly linked with multidrug resistance (MDR) in tumors where overexpression of these proteins often nullifies the effects of chemotherapeutics by removing the therapeutics from the cells. In hopes of creating co‐therapeutics to re‐sensitize tumors to chemotherapeutics, we previously used high‐throughput in silico ligand docking studies and identified drug‐like compounds that reversed MDR in human cancer cells in culture. The effects on P‐gp ATPase hydrolysis activity were used as an initial biochemical screen for inhibitor effectiveness followed by assessments of MDR‐reversal in various P‐gp overexpressing cancer cell lines. For the initial biochemical analyses, P‐glycoprotein (MDR3) from mouse was used, which is closely related to the human (MDR1) protein. To evaluate the mechanism of inhibition also in the human P‐protein, we have isolated human P‐gp from the yeast Pichia pastoris using mixed detergent micelles. Lipid activation of ABC transporters has been shown previously to be a vital step in ensuring best enzyme activity for the analysis of such proteins. In our pursuit to optimize the P‐gp ATPase activity, we have varied amounts and combinations of different lipids including phosphatidylcholine (PC), E. coli lipids and cholesterol and assessed the resulting ATPase hydrolysis activities in coupled enzyme assays. Preliminary results showed P‐gp activity in the presence of PC was significantly higher than when E. coli lipids were used. Here we report our efforts to achieve the best protein:lipid ratios as well as assess various techniques to achieve the high ATP hydrolysis activity of P‐gp to test our newly found drug‐like molecules in their effectiveness as P‐gp inhibitors.Support or Funding InformationThis work was supported by NIH NIGMS [R15GM094771‐02] to PDV and JGW, SMU University Research Council, SMU Hamilton Undergraduate Research Scholars and Undergraduate Research Assistantship Programs, the SMU Center for Drug Discovery, Design and Delivery, the Communities Foundation of Texas, and a private gift from Ms. Suzy Ruff of Dallas, Texas. The authors would like to thank Dr. Ina L. Urbatsch, Texas Tech University Health Science Center, for providing the P. pastoris cells expressing the human wild‐type MDR1 used in this work.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Reversal of Multidrug Resistance in Human Colon Cancer and Human Leukemia Cells by Three Plant Extracts and Their Major Secondary Metabolites.

Background: We studied the effect of three plant extracts (Glycyrrhiza glabra, Paeonia lactiflora, Eriobotrya japonica) and six of their major secondary metabolites (glycyrrhizic acid, 18β glycyrrhetinic acid, liquiritigenin, isoliquiritigenin, paeoniflorin, ursolic acid) on the multidrug resistant human colon cancer cell line Caco-2 and human leukemia cell line CEM/ADR 5000 as compared to the corresponding sensitive cell line CCRF-CEM, and human colon cancer cells HCT-116, which do not over-express ATP-binding cassette (ABC) transporters. Methods: The cytotoxicity of single substances in sensitive and resistant cells was investigated by MTT assay. We also applied combinations of extracts or single compounds with the chemotherapeutic agent doxorubicin or doxorubicin plus the saponin digitonin. The intracellular retention of the ABC transporter substrates rhodamine 123 and calcein was examined by flow cytometry to explore the effect of the substances on the activity of ABC transporters P-glycoprotein and MRP1. Real-time PCR was applied to analyse the gene expression changes of ABCB1, ABCC1, caspase 3, caspase 8, AhR, CYP1A1, and GSTP1 in resistant cells under the treatment of the substances. Results: All the substances moderately inhibited cell growth in sensitive and resistant cells to some degree. Whereas ursolic acid showed IC50 of 14 and 22 µM in CEM/ADR 5000 and Caco-2 cells, respectively, glycyrrhizic acid and paeoniflorin were inactive with IC50 values above 400 μM. Except for liquiritigenin and isoliquiritigenin, all the other substances reversed MDR in CEM/ADR 5000 and Caco-2 cells to doxorubicin. Ue, ga, 18ga, and urs were powerful reversal agents. In CEM/ADR 5000 cells, high concentrations of all the substances, except Paeonia lactiflora extract, increased calcein or rhodamine 123 retention in a dose-dependent manner. In Caco-2 cells, all the substances, except liquiritigenin, retained rhodamine 123 in a dose-dependent manner. We also examined the effect of the plant secondary metabolite (PSM) panel on the expression of ABCB1, ABCC1, caspase 3, caspase 8, AhR, CYP1A1, and GSTP1 genes in MDR cells. Conclusions: The extracts and individual PSM could reverse MDR in CEM/ADR 5000 and Caco-2 cells, which overexpress ABC transporters, in two- and three-drug combinations. Most of the PSM also inhibited the activity of ABC transporters to some degree, albeit at high concentrations. Ue, ga, 18ga, and urs were identified as potential multidrug resistance (MDR) modulator candidates, which need to be characterized and validated in further studies.

Differential Sensitivities of Human Multidrug-resistant Cancer Cells to BIIB021 and Modulation of Hsp90 Inhibitors by NSAIDs and Niclosamide

Differential Sensitivities of Human Multidrug-resistant Cancer Cells to BIIB021 and Modulation of Hsp90 Inhibitors by NSAIDs and Niclosamide

Nitric oxide reverses drug resistance by inhibiting ATPase activity of p-glycoprotein in human multi-drug resistant cancer cells

BackgroundDevelopment of resistance to chemotherapy drugs is a significant problem in treating human malignancies in the clinic. Overexpression of drug efflux proteins, including P-170 glycoprotein (P-gp), an ATP-dependent efflux protein, is one of the main mechanisms responsible for multi-drug resistance (MDR). Because our previous studies have shown that nitric oxide (˙NO) or its related species inhibit the ATPase activities of topoisomerase II, we hypothesized that ˙NO should also inhibit the ATPase activity of P-gp and increase drug accumulation in MDR cells, causing a reversal of drug resistance. ResultsCytotoxicity and cellular accumulation studies showed that ˙NO significantly inhibited the ATPase activity of P-gp in isolated membranes and in NCI/ADR-RES tumor cells, causing an increase in drug accumulation and reversals of adriamycin and taxol resistance in the MDR cells. While ˙NO had no effects on topoisomerase II-induced, adriamycin-dependent DNA cleavage complex formation, it significantly inhibited adriamycin-induced DNA double-strand breaks. Electron spin resonance studies showed an increase in adriamycin-dependent hydroxyl radical formation in the presence of an NO-donor. ConclusionsThe reversal of drug resistance is due to inhibition of the ATPase activity by ˙NO, resulting in enhancement of the drug accumulation in the MDR cells. Furthermore, DNA damage was not responsible for this reversal of adriamycin resistance. However, formation of adriamycin-dependent toxic free radical species and subsequent cellular damage may be responsible for the increased cytotoxicity of adriamycin by ˙NO in NCI/ADR-RES cells. General significanceAppropriately designed NO donors would be ideal for the treatment of P-gp-overexpressing tumors in the clinic.

The positive inotropic agent DPI-201106 selectively reverses ABCB1-mediated multidrug resistance in cancer cell lines

The overexpression of ABCB1 in cancer cells is a major factor contributing to the development of multidrug resistance (MDR) and treatment failure in cancer patients. Therefore, re-sensitization of MDR cancer cells to anticancer drugs remains an important aspect in chemotherapy. The progress in developing clinically applicable synthetic inhibitors of ABCB1 has been slow, mostly due to complications associated with intrinsic toxicities and unforeseen drug-drug interactions. Here, we explored the drug-repositioning approach for cancer therapy by targeting ABCB1-mediated MDR in human cancer cells. We found that DPI-201106, a positive inotropic agent, selectively inhibits the drug efflux function of ABCB1, and in doing so, re-sensitizes ABCB1-overexpressing MDR cancer cells to conventional anticancer drugs. Furthermore, the ATPase activity of ABCB1 and docking analysis of DPI-201106 in the drug-binding pocket of ABCB1 were determined to confirm the interaction between DPI-201106 and ABCB1 protein. In summary, we revealed an additional action and a potential clinical application of DPI-201106 to reverse ABCB1-mediated MDR in human cancer cells, which may be beneficial for cancer patients who have developed multidrug resistance and no longer respond to conventional chemotherapy, and should be further investigated.

Abstract 4195: β-elemene inhibits the metastasis of multidrug-resistant gastric cancer cells through the Cbl-b-EGFR-ERK/Akt signaling pathway

Abstract Background/Aims: β-elemene, a Curcuma wenyujin plant extract, has been widely used as an adjuvant therapeutic agent in cancer treatment. The emergence of drug-resistant tumor cells is defined as multidrug resistance (MDR), and is one of the major ways cancer therapy can fail. Our previous study indicated that, compared to chemo-sensitive human gastric cancer cells, drug-resistant cells have a stronger ability for migration. The aim of this study was to explore the anti-metastasis effects and mechanism of β-elemene in multi-drug resistance human gastric cancer cells. Methods: A cell viability assay was used to assess the resistance of adriamycin-resistant human gastric cancer SGC7901 cells (SGC7901/ADR) and the cytotoxic effects of β-elemene on SGC7901/ADR cells. A wound healing assay and transwell assay were used to explore the anti-metastasis effects of β-elemene. Human matrix metalloproteinase (MMP) antibody array and Western blot analysis were used to explore the potential mechanism. A murine tumor metastasis assay was used to confirm the anti-metastasis effects in vivo. Immunohistochemistry analysis was performed to examine the expressions of related proteins in xenograft tumors. Results: At sub-lethal concentrations (1 μg/ml and 5 μg/ml), β-elemene significantly inhibited cell migration and invasion of SGC7901/ADR cells. The human MMP antibody array indicated that β-elemene could regulate almost all proteins of the MMP family, and changes of MMP-2 and MMP-9 were the most obvious. Western blotting showed an increase of E-cadherin and decrease of vimentin in β-elemene-treated cells. Downregulation of transcription factor ZEB1 and ZEB2 was also detected. Treatment of SGC7901/ADR cells with β-elemene led to downregulation of Akt, ERK, and EGFR phosphorylation, and significant upregulation of the E3 ubiquitin ligase, Cbl-b. Changes of these proteins were confirmed in xenograft tumors. Hematoxylin and eosin staining showed significantly decreased numbers of metastatic tumor colonies in the lungs of nude mice injected with SGC7901/ADR cells and β-elemene compared with those only injected with SGC7901/ADR cells. Conclusions: The results strongly suggest that β-elemene inhibits the metastasis of multidrug-resistant gastric cancer cells in vitro and in vivo by regulating the Cbl-b-EGFR-ERK/Akt signaling pathway. β-elemene may be a promising treatment for multidrug resistant human gastric cancer. Citation Format: Ruoxi Yu, Mingming Deng, Huicong Song, Dan Zou, Ling Xu, Xiujuan Qu, Yunpeng Liu, Yuee Teng, Xuejun Hu, Ye Zhang. β-elemene inhibits the metastasis of multidrug-resistant gastric cancer cells through the Cbl-b-EGFR-ERK/Akt signaling pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4195.

The antioxidant, aged garlic extract, exerts cytotoxic effects on wild-type and multidrug-resistant human cancer cells by altering mitochondrial permeability

Aged garlic extract (AGE) has been shown to possess therapeutic properties in cancer; however its mechanisms of action are unclear. In this study, we demonstrate by MTT assay that AGE exerts an anti-proliferative effect on a panel of both sensitive and multidrug-resistant (MDR) human cancer cell lines and enhances the effects of hyperthermia (42˚C) on M14 melanoma cells. The evaluation of the mitochondrial activity in whole cancer cells treated with AGE, performed by cytofluorimetric analysis in the presence of the lipophilic cationic fluorochrome JC-1, revealed the occurrence of dose-dependent mitochondrial membrane depolarization. Membrane potential was measured by the TPP+ selective electrode. In order to shed light on its mechanisms of action, the effects of AGE on isolated rat liver mitochondria were also examined. In this regard, AGE induced a mitochondrial membrane hyperpolarization of approximately 15mV through a mechanism that was similar to that observed with the ionophores, nigericin or salinomycin, by activating an exchange between endogenous K+ with exogenous H+. The prolonged incubation of the mitochondria with AGE induced depolarization and matrix swelling, indicative of mitochondrial permeability transition induction that, however, occurs through a different mechanism from the well-known one. In particular, the transition pore opening induced by AGE was due to the rearrangement of the mitochondrial membranes following the increased activity of the K+/H+ exchanger. On the whole, the findings of this study indicate that AGE exerts cytotoxic effects on cancer cells by altering mitochondrial permeability. In particular, AGE in the mitochondria activates K+/H+ exchanger, causes oxidative stress and induces mitochondrial permeability transition(MPT).

Chinese herbal medicine Euphorbia esula extract induces apoptosis and inhibits the proliferation, migration and invasion of multidrug resistant gastric carcinoma cells

This paper aims to study the effects of traditional Chinese medicine Euphorbia esula on multidrug resistant human gastric cancer cells in the cell proliferation, migration, invasion and apoptosis, and to study the apoptosis-inducing pathway. Different dilutions of Euphorbia esula extract were used to process human multidrug resistant gastric cancer SGC7901/ADR cells. Cell proliferation inhibition phenomenon was determined by MTT experiment. Nuclear morphological changes of apoptotic cells and apoptotic indexes were observed and determined by Hochest33528 staining followed with fluorescence microscope observing. Flow cytometry was used to detect cell apoptosis rate. Cell migration and invasion ability were observed and determined by Transwell method. Spectrophotometry was used to detect caspase-3 and caspase-9 enzyme activity. Western blotting was used to detect subcellular distribution of cytochrome c. The results showed that Euphorbia esula extract had obvious inhibition effect on proliferation of gastric cancer multidrug resistant SGC7901/ADR cells, which was time- and concentration-dependent. After processing multidrug resistant gastric cancer SGC7901/ADR cells with Euphorbia esula extract, the apoptotic index and apoptosis rate were significantly increased than those in the control group, which showed a time- and dose-dependent mode; but if a caspase inhibitor was added, apoptosis index was not obviously increased. Transwell method showed that migration and invasion ability of the Euphorbia esula extract-processed SGC7901/ADR cells dropped significantly. Spectrophotometry showed that in Euphorbia esula extract-processed SGC7901/ADR cells, caspase-3 and caspase-9 expression were increased, which had significant differences with the control group. Western blotting test showed that the distribution of cytochrome c decreased in mitochondria, while increased in the cytoplasm (i.e., cytochrome c escaped from mitochondria to the cytoplasm). In conclusion, Euphorbia esula extract could inhibit the proliferation, migration and invasion, and induce apoptosis in human gastric cancer multidrug resistant SGC7901/ADR cells; and cytochrome c, caspase-9 and caspase-3 might be involved in cell apoptosis induced by Euphorbia esula extract, suggesting endogenous or mitochondrial apoptotic pathway.

Hexane fraction of adlay (Coix lachryma-jobi L.) testa ethanolic extract inhibits human uterine sarcoma cancer cells growth and chemosensitizes human uterine sarcoma cells to doxorubicin

BackgroundCancer has remained among the top ten causes of death in Taiwan since 1982. Uterine sarcoma is a rare gynecologic cancer, and chemotherapy is one type of cancer treatment. Doxorubicin (Dox) is widely used for treating several cancers, including uterine sarcoma, however, multidrug resistance (MDR) is a major clinical problem and a critical cause of treatment failure. The ethanolic extracts of adlay testa (ATE) exhibited significant anticancer activities against many cancer types. PurposeIn this study we investigated the antitumor effects of the hexane fraction of the adlay testa ethanolic extracts (ATE-Hex) on the human uterine sarcoma cancer cell line MES-SA, as well as on the multidrug-resistant human uterine sarcoma cancer cell line MES-SA/Dx5. MethodsThe MTT assay was performed to assess the effects of the extracts of different parts of the adlay on the proliferation of human uterine sarcoma cells (MES-SA and MES-SA/Dx5) and human uterine smooth muscle cells (HUtSMCs). To determine whether ATE-Hex has a chemosensitizing effect on drug-resistant uterine sarcoma cells, the MTT assay was performed to examine the synergistic effects of ATE-Hex, the chemotherapeutic drug Dox alone, and in combination. Rhodamine accumulation was analyzed using fluorescence detection. Apoptotic cells were analyzed via flow cytometry. In addition, employing a flame ionization detector (GC/FID) gas chromatography was also developed as the analysis platform for ATE-Hex. ResultsThe results demonstrated that ATE-Hex exhibited the best effects of inhibition on MES-SA and MES-SA/Dx5 cells. Co-treatment of ATE-Hex and Dox could synergistically inhibit the proliferation of cancer cells. ATE-Hex reduced the rhodamine efflux in MES-SA/Dx5 cells, indicating that ATE-Hex could reduce the expression of P-gp. In addition, our results showed that treatment with ATE-Hex alone or in combination with Dox significantly inhibited the growth of cancer cells and induced apoptosis by increasing the sub-G1 phase and poly(ADP-ribose) polymerase (PARP) being cleaved. Flow cytometry revealed that ATE-Hex induced apoptosis. ConclusionThese results suggest that ATE-Hex can inhibit human uterine sarcoma cancer cells by inducing apoptosis and increasing the chemosensitivity of the multidrug-resistant human uterine sarcoma cancer cell MES-SA/Dx5 to Dox. Furthermore, the combination of ATE-Hex and Dox could decrease MDR and increase the synergistic effect.

Curcumin Co-Treatment Sensitizes Multi-Drug Resistant Ht29 Colon Cancer Cell Line

Colorectal cancer has been confirmed to be the third most dreadful cancer across the world. The latest reports show that the colorectal cancer is increasing in India at a high rate due to food habits, particularly consuming the foods with high fat content. Chemotherapy has been considered as a potential treatment in the control of a wide range of cancers recently, such as gastrointestinal cancers and so on. The scientists are looking to come up with new drugs to treat cancer by regulating the carcinogenesis with minimal toxicity. Curcumin is a phytochemical extracted from turmeric. It is highly effective product of the rhizomes of Curcuma longa L. (Zingiberaceae). It is also considered as a valuable drug for chemotherapeutic treatments in cancer. In case of animal studies, it has been clearly mentioned that curcumin controls carcinogenesis in various other organs as well as colon. Curcumin exhibits the capability to act as anti-mutagenic, anti-inflammatory drug as well. It has also been confirmed that the P-gp expression regulation is carried out by curcumin by inhibiting the COX-2 expression. Also, it has been clearly stated that curcumin down-regulates NF-kB pathway in various cell lines like Colo 205 colon cancer cell line etc. Multi Drug Resistance (MDR) plays a key role in case of the cancer cells to exhibit the resistance against the cytotoxicity of various chemotherapeutic drugs. This type of characteristics in cancer cells is developed due to low levels of the chemotherapeutic drug accumulated inside the cells during repeated exposure to the drug, showing the over-expression of P-glycoprotein (MDR-1). P-glycoprotein, a transporter protein, allows the cells to expel the wide range of chemotherapeutic drugs. The latest reports show that COX-2 expression and P-gp expression possess strong correlation with each other. In this research study, we generated the Multi-Drug Resistant HT29 Human colon cancer cells by treating the cells with increasing concentrations of a chemotherapeutic drug namely Doxorubicin Hydrochloride (DOX) and further we estimated the intracellular drug concentration in treated live as well as dead cells with the help of Doxorubicin Accumulation Assay. Also, the cell morphology change was studied in HT29 cells after every 24 hours of the DOX treatment separately as well as curcumin co-treatment (DOX+Curcumin). The curcumin co-treatment was carried out to observe the effect of curcumin on multi-drug resistant HT29 colon cancer cells and further study can be extended to investigate the various inflammatory genes controlled by NFkB at mRNA and protein level as well as the levels of cytokines which may get down-regulated by treatment. This study will help to completely understand the mechanism of reducing the effect of Multidrug Resistance (a unique property of cancer) by curcumin in case of colon cancer.

Full extract of Euphorbia esula reversed chemoresistance, inhibited cell migration/invasion, and induced apoptosis of multidrug-resistant SGC7901/VCR cells

Background: The plant Euphorbia esula has been used by ancient Chinese people to treat cancer and other ailments and is used by present doctors or folks as an assistant treatment for some kind of cancers, but the mode of action is unclear. Objective: To investigate the influence of E. esula full extract on chemoresistance, cell migration/invasion, and apoptosis of multidrug-resistant human stomach cancer cells. Materials and Methods: After treating multidrug-resistant human stomach cancer SGC7901/VCR cells with E. esula extract at varying concentrations, the inhibition of cell proliferation was detected using thiazolyl blue. Sensitivity to the chemotherapeutic drugs, adriamycin and paclitaxel, was evaluated using half maximal inhibitory concentration. Cell cycle progression was analyzed by flow cytometry. The inhibitions of cell migration and invasion were examined by Transwell method. The induction of apoptosis and the apoptotic rate were studied by electron microscopy and flow cytometry, respectively. Activation of caspase 3 enzyme was inspected by ultraviolet spectrophotometry. Results: E. esula extract could increase the sensitivity of SGC7901/VCR cells to the chemotherapeutic drugs, adriamycin and paclitaxel. The proliferation, migration, and invasion of SGC7901/VCR cells were significantly inhibited by E. esula extract (P < 0.01 compared with negative control), which showed time- and dose-dependent manners (P < 0.05 and P < 0.01, respectively). Cell cycle was arrest at the S phase. E. esula extract also induced apoptosis in SGC7901/VCR cells, and the apoptotic rate was increased significantly with drug concentration and with treatment time (P < 0.01 compared with negative control, P < 0.05 between concentrations and time points). E. esula extract upregulated enzymatic activity of caspase 3. Conclusion: E. esula extract could reverse SGC7901/VCR cell's resistance to chemotherapeutic drugs and could inhibit cell proliferation, migration, and invasion, interfere with cell cycle progression, and induce apoptosis in SGC7901/VCR cells. Abbreviations used: E. esula: Euphorbia Esula; FCS: fetal calf serum; IC50: half maximal inhibitory concentration; OD: optical density.