scholarly journals Voruciclib, a Potent CDK4/6 Inhibitor, Antagonizes ABCB1 and ABCG2-Mediated Multi-Drug Resistance in Cancer Cells

2018 ◽  
Vol 45 (4) ◽  
pp. 1515-1528 ◽  
Author(s):  
Pranav Gupta ◽  
Yun-Kai Zhang ◽  
Xiao-Yu Zhang ◽  
Yi-Jun Wang ◽  
Kimberly W. Lu ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Cellular Localization ◽  
Intracellular Localization ◽  
Scintillation Counter ◽  
Flow Cytometric Analysis ◽  
Multi Drug Resistance ◽  
Dependent Manner ◽  
Cancer Drugs ◽  
Intracellular Accumulation ◽  
Anti Cancer

Background/Aims: The overexpression of ATP-Binding Cassette (ABC) transporters has known to be one of the major obstacles impeding the success of chemotherapy in drug resistant cancers. In this study, we evaluated voruciclib, a CDK 4/6 inhibitor, for its chemo-sensitizing activity in ABCB1- and ABCG2- overexpressing cells. Methods: Cytotoxicity and reversal effect of voruciclib was determined by MTT assay. The intracellular accumulation and efflux of ABCB1 and ABCG2 substrates were measured by scintillation counter. The effects on expression and intracellular localization of ABCB1 and ABCG2 proteins were determined by Western blotting and immunofluorescence, respectively. Vanadate-sensitive ATPase assay was done to determine the effect of voruciclib on the ATPase activity of ABCB1 and ABCG2. Flow cytometric analysis was done to determine the effect of voruciclib on apoptosis of ABCB1 and ABCG2-overexpressing cells and docking analysis was done to determine the interaction of voruciclib with ABCB1 and ACBG2 protein. Results: Voruciclib significantly potentiated the effect of paclitaxel and doxorubicin in ABCB1-overexpressing cells, as well as mitoxantrone and SN-38 in ABCG2-overexpressing cells. Voruciclib moderately sensitized ABCC10- overexpressing cells to paclitaxel, whereas it did not alter the cytotoxicity of substrates of ABCC1. Furthermore, voruciclib increased the intracellular accumulation and decreased the efflux of substrate anti-cancer drugs from ABCB1- or ABCG2-overexpressing cells. However, voruciclib did not alter the expression or the sub-cellular localization of ABCB1 or ABCG2. Voruciclib stimulated the ATPase activity of both ABCB1 and ABCG2 in a concentration-dependent manner. Lastly, voruciclib exhibited a drug-induced apoptotic effect in ABCB1- or ABCG2- overexpressing cells. Conclusion: Voruciclib is currently a phase I clinical trial drug. Our findings strongly support its potential use in combination with conventional anti-cancer drugs for cancer chemotherapy.

scholarly journals Ciprofloxacin Enhances the Chemosensitivity of Cancer Cells to ABCB1 Substrates

2019 ◽  
Vol 20 (2) ◽  
pp. 268 ◽  
Author(s):  
Pranav Gupta ◽  
Hai-Ling Gao ◽  
Yunali Ashar ◽  
Nishant Karadkhelkar ◽  
Sabesan Yoganathan ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Hematological Malignancies ◽  
Scintillation Counter ◽  
Dependent Manner ◽  
Intracellular Accumulation ◽  
Concentration Dependent Manner ◽  
Cytotoxic Effects ◽  
Docking Analysis ◽  
Atpase Assay ◽  
Major Drug

ABCB1 is one of the major drug efflux transporters that is known to cause multidrug resistance (MDR) in cancer patients receiving chemotherapy for the treatment of solid tumors and hematological malignancies. Inhibition of ABCB1 efflux function is important for maintaining the intracellular concentration of chemotherapeutic drugs. Here, we evaluated ciprofloxacin for its ability to reverse MDR caused by the overexpression of ABCB1. Cytotoxicity of ciprofloxacin was determined by the MTT assay. The chemosensitizing effects of ciprofloxacin were determined in combination with ABCB1 substrates. The intracellular accumulation and efflux of ABCB1 substrates was measured by a scintillation counter, and protein expression was determined by the Western blotting. Vanadate-sensitive ATPase assay was performed to determine the effect of ciprofloxacin on the ATPase activity of ABCB1, and docking analysis was done to determine the interaction of ciprofloxacin with ABCB1. Ciprofloxacin significantly potentiated the cytotoxic effects of ABCB1 substrates in ABCB1-overexpressing cells. Furthermore, ciprofloxacin increased the intracellular accumulation and decreased the efflux of [3H]-paclitaxel without altering the expression of ABCB1. Ciprofloxacin stimulated the ATPase activity of ABCB1 in a concentration-dependent manner. Our findings showed that ciprofloxacin potently inhibits the ABCB1 efflux function and it has potential to be developed as a combination anticancer therapy.

Comparison of the Effects on Reversal of Multi-Drug Resistance of 5-Bromotetrandrine and Tetrandrine in K562/A02 Cell Line in Vivo and in Vitro

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5059-5059
Author(s):  
Bao-An Chen ◽  
Jue-qiong Wang ◽  
Jian Cheng ◽  
Feng Gao ◽  
Wen-lin Xu ◽  
...  
Keyword(s):  
Cell Line ◽  
Nude Mice ◽  
Leukemia Cell Line ◽  
Multi Drug Resistance ◽  
Human Leukemia ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Intracellular Accumulation

Abstract Objective This study was to compare the reversal effect of 5-bromotetrandrine (BrTet) with Tetrandrine (Tet) when combined with ADM on multidrug resistance cell line K562/A02 and to investigate the reversal mechanism of this new derivative. Methods The protein levels of P-glycoprotein (P-gp) were detected by fluorospectrophotometry and Western blot. The mRNA levels of P-gp were determined by RT-PCR. The in vivo effect of Tet was investigated using nude mice grafted with sensitive human leukemia cell line K562 and MDR cell line K562/A02. Results Flow cytometry assay showed that 1.0 μMol/L BrTet significantly increased the apoptosis percentage. BrTet also enhanced the intracellular accumulation of ADM in K562/A02 cells and its potency was greater than that of Tet at the same concentrations. BrTet inhibited the overexpression of P-gp and down regulated MDR1 mRNA expression in K562/A02 cells in a dose-dependent manner. In nude mice bearing K562 xenografts on the left flank and K562/A02 xenografts on the right flank, i.p. injection of 10 mg/kg BrTet significantly enhanced the antitumor activity of ADM against K562/A02 xenografts with inhibitory rates of 26.1%, while ADM alone inhibited the growth of KBv200 xenografts by only 5.8%. Conclusion BrTet showed significant MDR reversal activity in vitro and in vivo. Its activity may be related to the inhibition of P-gp overexpression and the increase in intracellular accumulation of anticancer drugs, which lead to more K562/A02 cells apoptosis.

scholarly journals Comparison of responsiveness to cancer development and anti-cancer drug in three different C57BL/6N stocks

2019 ◽  
Vol 35 (1) ◽  
Author(s):  
Mi Ju Kang ◽  
Ji Eun Kim ◽  
Ji Won Park ◽  
Hyeon Jun Choi ◽  
Su Ji Bae ◽  
...  
Keyword(s):  
Animal Models ◽  
Tumor Tissue ◽  
Tumor Model ◽  
Cancer Drug ◽  
Dependent Manner ◽  
Cancer Drugs ◽  
Ki 67 ◽  
Anti Cancer ◽  
Dose Dependent ◽  
Syngeneic Model

Abstract In our efforts to understand the systemic features of tumors, the importance of animal models is increasing due to the recent growth in the development of immunotherapy and targeted therapies. This has resulted in increased attention towards tumor animal models using C57BL/6N, which are mainly used in immunological studies. In this study, the C57BL/6NKorl stock and two other commercial stocks (C57BL/6NA and C57BL/N6B) are evaluated by comparing the occurrence of tumors using the syngeneic model; furthermore, we compare the response to anti-cancer drugs in the syngeneic model by evaluating survival, growth of tumors, proliferation and molecular biology analysis. In the syngeneic model using LLC (Lewis lung carcinoma) cells, the survival of mice and growth of the tumor showed a better response in the C57BL/6NKorl stock, and was dependent on the cell concentration of the dosing tumor, as compared to the other C57BL/6N stocks. However, the Ki-67 staining showed only little difference in cell proliferation within the tumor tissue each mouse stocks. Comparing the sensitivity to anti-cancer drug by examining changes in growth, volume and weight revealed that cisplatin treatment for tumor-bearing C57BL/6NKorl was more dependent on concentration. The Ki-67 staining, however, showed no difference among the C57BL/6N stocks after cisplatin treatment. The expressions of p27 and p53 tumor suppressor proteins, caspase-3 and Bax showed dose-dependent increase after exposure to cisplatin, whereas the expression of Bcl-2 was reduced in a dose-dependent manner. Furthermore, the expressions of MMP-2 and VEGF involved in metastasis, as well as inflammatory genes IL-1β, IL-6 and IL-10, showed dose-dependent decrease in tumor tissue after cisplatin exposure. Differences observed among the C57BL/6N stocks were not significant. Taken together, our studies reveal that C57BL/6NKorl has the potential of being a useful biological resource established in Korea, as it does not differ from the two commercially available C57BL/6N stocks when considering response to tumor generation and sensitivity to anti-cancer drugs using the syngeneic tumor model.

Functional Analysis of a Cation Transporter OCT6: A Mediator of the Cellular Influx of Adriamycin.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4374-4374
Author(s):  
Yoko Okitsu ◽  
Hideo Harigae ◽  
Shinichiro Takahashi ◽  
Shori Abe ◽  
Mitsunori Okabe ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Xenopus Oocytes ◽  
Intracellular Concentration ◽  
Myelogenous Leukemia ◽  
Leukemic Cells ◽  
Leukemia Cell Line ◽  
Clinical Samples ◽  
Dependent Manner ◽  
Cancer Drugs ◽  
Anti Cancer

Abstract (Introduction) It is necessary for killing leukemic cells effectively to achieve a sufficient intracellular concentration of anti-cancer drugs. To date, overexpression of efflux pump such as MDR-1 and MRP-1, which leads to a decrease of cellular concentration of drugs, has been shown to attenuate the therapeutic effect of anti-cancer drugs and correlate with low remission rate in acute leukemia. If the expression of genes, which import anti-cancer drugs, can be induced specifically in leukemic cells, it would lead to an increase of intracellular concentration, resulting in an enhancement of the pharmacological effect. In this study, we performed the pharmacological characterization of a cation transporter gene, OCT6, and explore the possibility of its application for anti-cancer therapy. (Methods) Tissue distribution of OCT6 was examined by Northern blot analysis. Expression in clinical samples that consist of 34 patients; 15 patients with acute lymphoblastic leukemia (ALL), 17 patients with acute myelogenous leukemia (AML), 2 patients with chronic myelogenous leukemia (CML) in blastic crisis, was examined by quantitative RT-PCR. The percentage of blasts in each sample was above 80%. For functional analysis, OCT6 cRNA was injected into Xenopus oocytes and pharmacological analysis was performed. In order to examine the transporting activity in hematopoietic cells, we established subclones of Jurkat, a T lymphocytic leukemia cell line, in which OCT6 gene is constitutively expressed, and the change of the sensitivity for adriamycin was examined. (Result) By Northernblot analysis, 2.4kb OCT6 mRNA was detected in testis and bone marrow in adult tissues. OCT6 expressed in Xenopus oocytes transported not only tetraethlammonium but also adriamycin in a saturable and dose-dependent manner. The apparent Km value for [14C] adriamycin was 5.2±0.4μM. On the other hand, OCT6 did not transport either of methotrexate (MTX) and 5-fluorouracil (5-FU), which are not organic cations. After the exposure of adrimycin at the therapeutic concentration, the viability of OCT6 overexpressing Jurkat cells was significantly decreased compared to that of control cells. Consistent with this, the percentage of apoptosis cells became higher than that of control cells. When the expression level was examined in clinical samples, the average of the levels of patients was comparable to PBMCs. The level of patients, who achieved with complete remission (CR), was slightly higher than that of patients with non-response (NR), but the difference was not significant. Some patients exhibited the high expression of OCT6, but the distribution did not deviated to either CR or NR group. (Conclusion) These results suggest that the induction of OCT6 in leukemic cells might be a novel strategy for leukemia treatment.

scholarly journals Emerging Significance of Flavonoids as P-Glycoprotein Inhibitors in Cancer Chemotherapy

2009 ◽  
Vol 12 (1) ◽  
pp. 46 ◽  
Author(s):  
Tripta Bansal ◽  
Manu Jaggi ◽  
Roop Khar ◽  
Sushama Talegaonkar
Keyword(s):  
Drug Resistance ◽  
Cancer Treatment ◽  
Blood Brain Barrier ◽  
Cancer Chemotherapy ◽  
Brain Barrier ◽  
Multi Drug Resistance ◽  
Cancer Drugs ◽  
P Glycoprotein ◽  
Blood Brain ◽  
Anti Cancer

Chemotherapy forms the mainstay of cancer treatment particularly for patients who do not respond to local excision or radiation treatment. However, cancer treatment by drugs is seriously limited by P-glycoprotein (P-gp) associated multi-drug resistance (MDR) in various tumor cells. On the other hand, it is now widely recognized that P-gp also influences drug transport across various biological membranes. P-gp transporter is widely present in the luminal surface of enterocytes, biliary canalicular surface of hepatocytes, apical surface of proximal tubular cells of kidney, endothelial cells of blood brain barrier, etc. thus affecting absorption, distribution, metabolism and excretion of xenobiotics. Clinical significance of above mentioned carrier is appreciated from the fact that more than fifty percent of existing anti-cancer drugs undergo inhibitable and saturable P-gp mediated efflux. Consequently, there is an increasing trend to optimize pharmacokinetics, enhance antitumour activity and reduce systemic toxicity of existing anti-cancer drugs by inhibiting P-gp mediated transport. Although a wide variety of P-gp inhibitors have been discovered, research efforts are underway to identify the most appropriate one. Flavonoids (polyphenolic herbal constituents) form the third generation, non-pharmaceutical category of P-gp inhibitors. The effects produced by some of these components are found to be comparable to those of well-known P-gp inhibitors verapamil and cyclosporine. Identification of effective P-gp modulator among herbal compounds have an added advantage of being safe, thereby making them ideal candidates for bioavailability enhancement, tissue-penetration (e.g. blood brain barrier (BBB)), decreasing biliary excretion and multi-drug resistance modulating agents. The dual effects, i.e. P-gp modulation and antitumor activity, of these herbal derivatives may synergistically act in cancer chemotherapy. This paper presents an overview of the investigations on the feasibility and application of flavonoids as P-gp modulators for improved efficacy of anti-cancer drugs like taxanes, anthracyclines, epipodophyllotoxins, camptothecins and vinca alkaloids. The review also focuses on flavonoid-drug interactions as well as the reversal activity of flavonoids useful against MDR. In addition, the experimental models which could be used for investigation on P-gp mediated efflux are also discussed.

scholarly journals Nutlin3a Contributes to the Cytoplasmic Retention of Androgen Receptor

Proceedings ◽  
2018 ◽  
Vol 2 (25) ◽  
pp. 1580
Author(s):  
Gulseren Ozduman ◽  
Bilge Debelec Butuner ◽  
Kemal Sami Korkmaz
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Cellular Localization ◽  
Nuclear Translocation ◽  
Intracellular Localization ◽  
Critical Role ◽  
Cancer Therapeutics ◽  
Luciferase Reporter ◽  
Dependent Manner ◽  
Normal Prostate

Prostate cancer cells need androgens to grow and maintain like normal prostate cells, both utilize that Androgen Receptor (AR) function. Androgen receptor (AR) is expressed throughout the prostate cancer progression plays a critical role as a transcription factor in castration-dependent stages of disease. AR also interacts to many cellular proteins, including p53, to regulate apoptosis. Further, as the stabilization of p53 protein triggers apoptosis, p53 interacting small molecules such as Nutlin3a, are interpreted as cancer therapeutics. In this study, to find out how Nutlin3a-mediated p53 stabilization effect on AR signaling. Here, we investigated the dynamics of p53 binding to transcriptional targets of AR, and further investigated the variations of AR intracellular localization as well as transactivation in the presence of Nutlin3a. To do this, the changes in AR transactivation were investigated via luciferase reporter assay, which was performed by treating LNCaPs with different doses of Nutlin3a and resulted that transactivation was suppressed by Nutlin3a in a dose dependent manner. AR transactivation and sub-cellular localization were also studied by immunofluorescence assay and found that cytoplasmic-nuclear fractionation-coupled western blot analysis showed that Nutlin3a inhibits AR phosphorylation and nuclear translocation regardless of androgens.

P-glycoprotein (ABCB1) interacts directly with lipid-based anti-cancer drugs and platelet-activating factorsThis paper is one of a selection of papers published in this Special Issue, entitled CSBMCB — Membrane Proteins in Health and Disease.

2006 ◽  
Vol 84 (6) ◽  
pp. 1022-1033 ◽  
Author(s):  
Paul D.W. Eckford ◽  
Frances J. Sharom
Keyword(s):  
Atpase Activity ◽  
Lipid A ◽  
Atp Hydrolysis ◽  
Membrane Lipids ◽  
Binding Pocket ◽  
Drug Binding ◽  
Cancer Drugs ◽  
Outer Leaflet ◽  
P Glycoprotein ◽  
Anti Cancer

The P-glycoprotein multidrug transporter (Pgp; ABCB1) is an ATP-binding cassette (ABC) protein that has been implicated in the multidrug resistance of human cancers. Pgp couples ATP hydrolysis to active extrusion from the cell of a broad array of amphipathic compounds via an ill-defined mechanism. Substrates are believed to interact with Pgp within the membrane. Reconstituted Pgp functions as an ATP-dependent flippase for a variety of fluorescently labelled membrane lipids. The protein may also function as a drug ‘flippase’, moving its substrates from the inner to the outer leaflet of the bilayer. We show that lipid-based anti-cancer drugs, such as miltefosine, and signaling molecules, such as platelet-activating factors, bind saturably to Pgp with Kd values in the low micromolar range, and modulate its ATPase activity. These compounds also inhibit Pgp-mediated flipping of fluorescent lipids and transport of Hoechst 33342 and tetramethylrosamine, which occupy different subsites in the drug-binding pocket. Bacterial lipid A modulates Pgp ATPase activity, and glycolipid flipping is inhibited by unlabelled glucosylceramide, suggesting that these lipids also interact with the transporter. These results indicate that Pgp treats a variety of lipid-based molecules as substrates, and likely interacts with lipids and drugs in the same manner.

The Immuno-Electron Microscopic Localization of the Mo-Fe Protein Component of Nitrogenase in Cells of Azotobacter Vinelandii

1973 ◽  
Vol 31 ◽  
pp. 574-575
Author(s):  
J. T. Stasny ◽  
R. C. Burns ◽  
R. W. F. Hardy
Keyword(s):  
Cellular Localization ◽  
Direct Evidence ◽  
Azotobacter Vinelandii ◽  
Intracellular Localization ◽  
Protein Component ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Fe Protein ◽  
Intracytoplasmic Membranes

Structure-functlon studies of biological N2-fixation have correlated the presence of the enzyme nitrogenase with increased numbers of intracytoplasmic membranes in Azotobacter. However no direct evidence has been provided for the internal cellular localization of any nitrogenase. Recent advances concerned with the crystallizatiorTand the electron microscopic characterization of the Mo-Fe protein component of Azotobacter nitrogenase, prompted the use of this purified protein to obtain antibodies (Ab) to be conjugated to electron dense markers for the intracellular localization of the protein by electron microscopy. The present study describes the use of ferritin conjugated to goat antitMo-Fe protein immunoglobulin (IgG) and the observations following its topical application to thin sections of N2-grown Azotobacter.

A Case of Malignant Melanoma Treated with a Combination of Anti-Cancer Drugs and Biological Response Modifiers.

1993 ◽  
Vol 55 (1) ◽  
pp. 43-46
Author(s):  
Jun YOSHIDA ◽  
Juichiro NAKAYAMA ◽  
Nobuyuki SHIMIZU ◽  
Shonosuke NAGAE ◽  
Yoshiaki HORI
Keyword(s):  
Malignant Melanoma ◽  
Biological Response ◽  
Biological Response Modifiers ◽  
Cancer Drugs ◽  
Anti Cancer
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