Cytotoxicity Of Doxorubicin Research Articles

Preparation of Chitosan Antioxidant Nanoparticles as Drug Delivery System for Enhancing of Anti-Cancer Drug

Chemotherapy is a major therapeutic approach for the treatment of localized and metastasized cancers. Although Doxorubicin (DOX) possesses abroad spectrum of anticancer activity, its clinical use is limited because of it cause heart failure. Chitosan nanoparticles was prepared by using ionic gelation method. These nanoaparticles were used as polyload of anticancer DOX to form safer and non-toxic anticancer drug. infrared spectroscopy (FTIR) and transmission electron microscope (TEM) were used to characterize the prepared nanoparticles. The cancer animals’ experiments using Ehrlich static cancer, (EAC) cells using six groups of experimental animals were performed to evaluate the efficiency of Doxorubicin and Doxorubicin loaded chitosan nanoparticles as anticancer drug especially from its toxicity towards heart. Tumor volume was calculated as to monitor the response to treatment. Cytotoxicity of Doxorubicin and Doxorubicin loaded chitosan nanoparticles were evaluated. Biochemical parameters were be estimated to illustrate the cytotoxicity of these drugs on heart.

Divergent Activity of the Pseudogene PTENP1 in ER-Positive and Negative Breast Cancer.

Transcripts derived from the PTEN pseudogene (PTENP1) function as decoys to adsorb miRNAs targeting the PTEN tumor suppressor for degradation, and PTENP1 upregulation is known to inhibit growth in preclinical cancer models. Here, PTENP1 3'UTR transduction influences PTEN, AKT/mTOR signaling, and tumor progression in estrogen receptor (ER)-positive and -negative breast cancer cells. PTENP1 upregulation decreases PTEN gene expression in the ER-positive MCF7 and T47D human breast carcinoma cells and accelerates MCF7 tumor growth in vivo Of note, PTENP1 transduction significantly decreases ERα (ESR1) mRNA and protein levels in MCF7 xenografts with a concomitant increase in hsa-miR-26a, a miRNA known to target ESR1 In the ER-negative MDA-MB-231 and C3HBA breast cancer cells, upregulation of PTENP1 increases PTEN gene expression with no influence on hsa-miR-26a, ESR1, or ERα expression. While PTENP1 transduction did not influence the growth rate of human MDA-MB-231 xenografts, PTENP1 upregulation profoundly reduces its metastatic propensity. Furthermore, PTENP1 significantly inhibits the growth rate of ER-negative C3HBA murine breast cancer xenografts. PTENP1 transduction had no influence on doxorubicin cytotoxicity in ER-positive MCF7 cells but an increase in doxorubicin sensitivity was observed in the ER-negative MDA-MB-231 cells. In summary, while PTENP1 upregulation decreased PTEN transcript levels and stimulated the growth of ER-positive breast cancers, increased PTEN transcript levels and inhibited tumor progression was observed in the ER-negative cells.Implications: This report highlights the profound biological activity of PTENP1 in breast cancer, which is dictated by the hormone receptor status. Mol Cancer Res; 16(1); 78-89. ©2017 AACR.

Comprehensive assessment of the association between topoisomerase single nucleotide polymorphism and doxorubicin cytotoxicity

Comprehensive assessment of the association between topoisomerase single nucleotide polymorphism and doxorubicin cytotoxicity

ZnO nanofluids for the improved cytotoxicity and cellular uptake of doxorubicin

Objective(s): Combination anticancer therapy holds promise for improving the therapeutic efficacy of chemotherapy drugs such as doxorubicin (DOX) as well as decreasing their dose-limiting side effects. Overcoming the side effects of doxorubicin (DOX) is a major challenge to the effective treatment of cancer. Zinc oxide nanoparticles (ZnO NPs) are emerging as potent tools for a wide variety of biomedical applications. The aim of this study was to develop a combinatorial approach for enhancing the anticancer efficacy and cellular uptake of DOX. Materials and Methods: ZnO NPs were synthesized by the solvothermal method and were characterized by X-ray diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM). ZnO NPs were dispersed in 10% bovine serum albumin (BSA) and the cytotoxic effect of the resulting ZnO nanofluids was evaluated alone and in combination with DOX on DU145 cells. The influence of ZnO nanofluids on the cellular uptake of DOX and DOX-induced catalase mRNA expression were investigated by fluorescence microscopy and semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), respectively. Results: The MTT results revealed that ZnO nanofluids decreased the cell viability of DU145 cells in a timeand dose-dependent manner. Simultaneous combination treatment of DOX and ZnO nanofluid showed a significant increase in anticancer activity and the cellular uptake of DOX compared to DOX alone. Also, a time-dependent reduction of catalase mRNA expression was observed in the cells treated with ZnO nanofluids and DOX, alone and in combination with each other. Conclusion: These results indicate the role of ZnO nanofluid as a growth-inhibitory agent and a drug delivery system for DOX in DU145 cells. Thus, ZnO nanofluid could be a candidate for combination chemotherapy.

The Combination of Omega-3 Stearidonic Acid and Docetaxel Enhances Cell Death over Docetaxel Alone in Human Prostate Cancer Cells.

Background: Docetaxel (DOC), or Taxotere, is an anthracycline antibiotic used to treat multiple types of cancer. It is a first-line chemotherapy treatment for patients with metastasized, hormone-resistant prostate cancer (PCa) or for patients with high-risk, localized PCa that could benefit from early chemotherapy treatment. Previously, we showed that stearidonic acid (SDA), an omega-3 fatty acid, enhances the cytotoxicity of doxorubicin (DOX) in human PCa cells. This observation suggests that PCa therapies using SDA and chemotherapeutic drugs in combination offer attractive possibilities for developing treatments that ameliorate toxic side effects of some commonly used chemotherapy drugs.Objectives: We used androgen-resistant PC3 and DU 145 cells derived from human prostate cancer to quantify the effects of combined SDA and DOC on proliferation/viability and on the production of pro-apoptotic caspases 9 and 3. We also compared the effects of SDA with those of BAY, a pharmacological inhibitor of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB), in androgen-sensitive LNCaP cells. Finally, we qualitatively and quantitatively assessed the drug combination on androgen receptor (AR) and peroxisome proliferator-activated receptor gamma (PPARγ) expression in LNCaP and PC3 cells, respectively.Methods: The half maximal inhibitory concentration (IC50) and combination indices of SDA and DOC in PC3 and DU 145 cells were determined using the MTT cell viability assay. To quantify the effects of SDA and BAY on NF-ĸB activity, we used luciferase reporter assays in LNCaP cells that were stably transduced with lentiviral vectors carrying NF-ĸB response element sequence upstream of the luciferase gene sequence. AR and PPARγ expression were assessed by western blotting and immunocytochemistry. We considered caspase 9 and 3 cleavage to be apoptosis markers and determined the drug combination effect on the extent of that cleavage by western blot analysis.Results: The cytotoxic effects of DOC were synergistically enhanced by SDA when the two were added to DU145 and PC3 cell cultures. Combination index (CI) analyses based on the Chou-Talalay method and mass action law showed synergistic interaction with CI <1. SDA suppressed TNFα-induced NF-κB activity similarly to BAY. The SDA/DOC combination down regulated testosterone (T)-induced AR and troglitazone-induced PPARγ protein expression when compared to using the drugs singly. Similarly, the SDA/DOC combination induced caspase 9 and 3 production and cleavage suggesting apoptosis induction. Like our DOX studies, this work provides proof-of-concept for using SDA and DOC in combination to reduce the dose, and therefore the toxicity, of DOC and possibly increasing the survival benefit in DOC clinical translation studies.

Eukaryotic translation initiation factor 5A-2 involves in doxorubicin-induced epithelial-mesenchymal transition in oral squamous cell carcinoma cells.

Background: Epithelial-mesenchymal transition (EMT) is considered to be vital during chemotherapy resistance in oral squamous cell carcinoma (OSCC). Recently, eukaryotic initiation factor 5A-2 (eIF5A-2), a potential oncogene, has been reported to be involved in chemotherapy resistance in human cancers.Materials and Methods: N1-guanyl-1,7-diaminoheptane (GC7, a novel eIF5A-2 inhibitor) or siRNA on responses to doxorubicin were examined in OSCC cells. Cytotoxicity and protein expression were evaluated by CCK-8 and EdU incorporation assay and western blotting. Tca8113 cells were used for establishment and treatment of tumor xenografts in vivo.Results: Low concentration of GC7 (5μΜ) significantly enhanced doxorubicin cytotoxicity in both epithelial phenotype OSCC cells (Cal27) and mesenchymal phenotype OSCC cells (HN30 and Tca8113). EMT process promoted by doxorubicin in Cal27 cells could be reversed by GC7. Additionally, GC7 induced mesenchymal-epithelial transition (MET) in HN30 and Tca8113 cells. Silencing of eIF5A-2 by specific siRNA exhibited the similar effects. The synergistic cytotoxicity of doxorubicin/GC7 combination was not induced in Twist-1, an EMT driving factor, silenced Cal27, HN30, and Tca8113 cells. GC7 also synergized doxorubicin to inhibit tumor growth in vivo treatment.Conclusions: Our study strongly proved that combined treatment with GC7 may boost the therapeutic effect of doxorubicin in OSCC by inhibiting the EMT.

Development of In Vitro Drug-Induced Cardiotoxicity Assay by Using Three-Dimensional Cardiac Tissues Derived from Human Induced Pluripotent Stem Cells.

An in vitro drug-induced cardiotoxicity assay is a critical step in drug discovery for clinical use. The use of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) is promising for this purpose. However, single hiPSC-CMs are limited in their ability to mimic native cardiac tissue structurally and functionally, and the generation of artificial cardiac tissue using hiPSC-CMs is an ongoing challenging. We therefore developed a new method of constructing three-dimensional (3D) artificial tissues in a short time by coating extracellular matrix (ECM) components on cell surfaces. We hypothesized that 3D cardiac tissues derived from hiPSC-CMs (3D-hiPSC-CT) could be used for an in vitro drug-induced cardiotoxicity assay. 3D-hiPSC-CT were generated by fibronectin and gelatin nanofilm coated single hiPSC-CMs. Histologically, 3D-hiPSC-CT exhibited a sarcomere structure in the myocytes and ECM proteins, such as fibronectin, collagen type I/III, and laminin. The administration of cytotoxic doxorubicin at 5.0 μM induced the release of lactate dehydrogenase, while that at 2.0 μM reduced the cell viability. E-4031, human ether-a-go-go related gene (hERG)-type potassium channel blocker, and isoproterenol induced significant changes both in the Ca transient parameters and contractile parameters in a dose-dependent manner. The 3D-hiPSC-CT exhibited doxorubicin-sensitive cytotoxicity and hERG channel blocker/isoproterenol-sensitive electrical activity in vitro, indicating its usefulness for drug-induced cardiotoxicity assays or drug screening systems for drug discovery.

Chemical characterization, antioxidant, genotoxic and in vitro cytotoxic activity assessment of Juniperus communis var. saxatilis

Chemical composition and antioxidative, genotoxic and cytotoxic potential of essential oil (EO) and post-distillation waste (PDW) of Serbian Juniperus communis L. var. saxatilis Pall. was studied in human lung carcinoma (A549) and normal lung fibroblast (MRC-5) cells. GC-MS analysis identified 93.95% of total EO content and determined α-pinen as a dominant component (23.61%). LC-MS/MS analysis of PDW pointed at rutin (12.2 mg g−1) and quinic acid (11.1 mg g−1) as the most abundant. Antioxidativity of PDW was strong in DPPH (IC50 was 5.27 μg mL−1), and moderate in TBA and FRAP assays. Both substances were more cytotoxic to A549 than to MRC-5 cells. Obtained IC50 values were 69.4 μg mL−1 and 120 μg mL−1 for EO, and 1.27 mg mL−1 and 2.86 mg mL−1 for PDW, respectively. PDW was genotoxic (0.3 mg mL−1 and 1 mg mL−1 in A549 and MRC-5 cells, respectively) and induced apoptosis and arrested cell cycle in G2/M phase in A549 cells (0.3 mg mL−1). In mixtures with doxorubicin cytotoxicity of EO and PDW increased, and combination index values (0.12–0.18) revealed clear synergistic effect, stronger in cancer cells. This indicates that J. communis var. saxatilis could decrease the chemotherapeutic doses of doxorubicin, potentially reducing its side effects.

In vitro modulation of the cytochrome P450 and ABCB1/P-glycoprotein activities of the aqueous extract of Allophylus cominia (L) Sw. leaves.

The aqueous extract of the Allophylus cominia (L) Sw (Sapindaceae) leaves has shown anti-diabetic, anti-obesity and anti-inflammatory properties. In the Caribbean region, it is typically used for the treatment of type-2 diabetes. Considering the herb-drug interaction, the aim of this study was to evaluate the potential effects of the A. cominia extract on the cytochrome P450 (CYP) (rat hepatocyte model) and P-glycoprotein (P-gp) (4T1 cell line) systems. The extract did not decrease the cell viability after being assayed by the MTT test at up to 1500 μg/mL for 72 h. The exposure of the cultured rat hepatocytes to the product (up to 250 μg/mL) for 48 h increased the activities of CYP-1A2, 2C9, and 2E1 by 1.46-, 1.60-, and 1.51-fold, respectively, compared with the controls. The activities of CYP-2B6, 2D6, and 3A4 were not significantly altered, whereas the activity of P-gp decreased by 2- and 4-fold. In addition, the extracts at 100 and 200 μg/mL significantly increased doxorubicin cytotoxicity in these cells 24 h after treatment. The findings indicate that the A. cominia extract modulates the CYP and P-gp systems increasing sensitivity to doxorubicin. Further studies are necessary to evaluate the potential herb-drug interaction or chemosensitive properties.

Synthesis of Nontoxic Protoflavone Derivatives through Selective Continuous‐Flow Hydrogenation of the Flavonoid B‐Ring

Protoflavones are unique natural flavonoids with a non-aromatic B-ring, known for their potent antitumor properties. However, their cytotoxicity represents a strong limitation in the further exploration of their pharmacological potential. In the current study, we sought to selectively saturate the p-quinol B-ring of protoapigenone and that of its 1'-O-butyl ether, in order to obtain non-toxic protoflavone analogues expressing the dihydro- or tetrahydroprotoflavone structure also occurring in nature. The benefits of a strictly controlled continuous-flow environment in combination with on-demand electrolytic H2 gas generation were exploited to suppress undesired side reactions and to safely and selectively yield the desired substances. The obtained tetrahydroprotoflavones were free of the cytotoxicity of their parent compounds, and, even though tetrahydroprotoapigenone 1-O-butyl ether showed a weak inhibition of DNA damage response through Chk1, neither compounds influenced the cytotoxicity of doxorubicin either.

Cytotoxic alkaloids against human colon adenocarcinoma cell line (HT-29) from the seed embryos of Nelumbo nucifera

Phytochemical investigation of the CHCl3 extract of the seed embryos of Nelumbo nucifera Gaertn resulted in the isolation of a new naturally occurring bisbenzylisoquinoline alkaloid, O-methylneferine (1), together with five known alkaloids, neferine (2), armepavine (3), (–)-(1R)-N-methylcoclaurine (4), nuciferine (5), and pronuciferine (6). The structures of these compounds were characterized by spectroscopic methods and comparison of physical properties with those reported in the literature. Among them, compounds 1 and 2 exhibited significant activity against human colon adenocarcinoma cell line (HT-29), with IC50 values of 0.70 and 1.61 µM, respectively, which were 8- and 3.5-fold higher than that of the reference anticancer drug, doxorubicin (IC50 5.63 µM). Moreover, compounds 1 and 2 displayed less cytotoxic activity against the non-cancerous HEK 239 cells with the IC50 values of 42.48 and 12.19 μM, respectively, whereas the cytotoxicity of doxorubicin against this cell line was 0.22 μM. The very potent cytotoxicity against HT-29 cell line and very high selectivity index (60.6-fold) of the alkaloid 1 is of particular significant; it could be considered as a promising structure lead for anti-colon cancer drug development.

In Vivo Pulmonary Delivery and Magnetic-Targeting of Dry Powder Nano-in-Microparticles.

This brief communication evaluates the cytotoxicity and targeting capability of a dry powder chemotherapeutic. Nano-in-microparticles (NIMs) are a dry powder drug delivery vehicle containing superparamagnetic iron oxide nanoparticles (SPIONs) and either doxorubicin (w/w solids) or fluorescent nanospheres (w/v during formulation; as a drug surrogate) in a lactose matrix. In vitro cytotoxicity was evaluated in A549 adenocarcinoma cells using MTS and LDH assays to assess viability and toxicity after 48 h of NIMs exposure. In vivo magnetic-field-dependent targeting of inhaled NIMs was evaluated in a healthy mouse model. Mice were endotracheally administered fluorescently labeled NIMs either as a dry powder or a liquid aerosol in the presence of an external magnet placed over the left lung. Quantification of fluorescence and iron showed a significant increase in both fluorescence intensity and iron content to the left magnetized lung. In comparison, we observed decreased targeting of fluorescent nanospheres to the left lung from an aerosolized liquid suspension, due to the dissociation of SPIONs and nanoparticles during pulmonary administration. We conclude that dry powder NIMs maintain the therapeutic cytotoxicity of doxorubicin and can be better targeted to specific regions of the lung in the presence of a magnetic field, compared to a liquid suspension.

A Src/Abl kinase inhibitor, bosutinib, downregulates and inhibits PARP enzyme and sensitizes cells to the DNA damaging agents

Abstract Background Poly(ADP-ribosyl)ation (PARylation) catalyzed mainly by PARP1 is a highly regulated posttranslational modification associated with several pathways in cellular physiology and genotoxic deoxyribonucleic acid (DNA) damage response. PAR polymers and PARP enzyme function in DNA integrity maintenance and several PARP inhibitors have entered clinical phase studies for cancer therapies. Material and methods The effect of bosutinib, a dual Src/Abl kinase inhibitor, on PARylation was fluorometrically measured. The cytotoxic and chemosensitizing effects were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The levels of DNA repair proteins and PARP enzyme were examined by immunoblotting. Results In this study, bosutinib is characterized as a novel PARP inhibitor. Bosutinib inhibited oxidative stress-induced cellular PARylation and nuclear foci formation by downregulating PARP1 levels. Bosutinib was found to be more cytotoxic on Capan1 cells with BRCA2 mutation. Furthermore by acting as a chemosensitizer, bosutinib enhanced the cytotoxicity of doxorubicin (DOXO) and etoposide (ETP) by decreasing phosphorylation of DNA repair enzymes checkpoint kinase 1 (Chk1) and ataxia-telangiectasia mutated (ATM). Conclusion By inhibition of both PARP and DNA damage checkpoint kinases, bosutinib increased the phospho-H2AX levels, an early indicator of DNA double strand breaks.

125 - ROS Increase Chemo-reagent Concentration by the Down Regulation of BCRP During Both Hyperthermia and Chemotherapy

Hyperthermia (HT) is a non-invasive cancer therapy. Treatment temperature between 41 to 44°C has no cytotoxic damage in normal cells, while the temperature does in cancer cells because of the underdeveloped vascular system. HT often used with other cancer therapy such as radiation-therapy and chemotherapy. However mechanisms of synergistic effects among these therapies remains unclear. The 42°C environment is a cellular mild heat stress generating O2‒ from mitochondrial electron transport chain. We have previously reported that the expression of ATP-binding cassette sub-family G member 2 (ABCG2), which is known as breast cancer resistant protein (BCRP), was suppressed by increasing mitochondrial reactive oxygen species (ROS) to induce cancer specific porphyrin accumulations. Since ABCG2 is a transporter of doxorubicin (DOX), we hypothesized that synergistic effect of HT and chemotherapy may be induced by down-regulation of ABCG2 expression via intracellular ROS increase. In this study, we elucidated whether HT with intracellular ROS increase by HT can enhance the cytotoxic effect of DOX for breast cancer cells. The murine breast cancer cell line, 4T1E was incubated at 37 or 42°C for 1h. Intracellular ROS generation was detected by electron spin resonance (ESR). Cytotoxicity of DOX was measured using the Cell Counting Kit 8. ABCG2 expression was analyzed by Western blotting. ESR signal peak with HT treatment became high as compared to without HT treatment, indicating intracellular ROS level was increased by HT treatment. Cell viability and ABCG2 expression were decreased by DOX exposure and by HT treatment. Thus we conclude that the enhancement of HT treatment effect by DOX is considered to be result of down-regulation of BCRP expression by ROS.

Ability of polymer-bound P-glycoprotein inhibitor ritonavir to overcome multidrug resistance in various resistant neuroblastoma cell lines.

Polymer prodrugs can considerably improve the treatment of tumors with multidrug resistance, often caused by overexpression of P-glycoprotein (P-gp). Here, we present the effect of the N-(2-hydroxypropyl) methacrylamide-based polymer conjugate with P-gp inhibitor ritonavir (RIT) on the increase of free doxorubicin (DOX) and polymer-bound DOX cytotoxicity in the human neuroblastoma 4 cell line and its resistant clones to different cytostatics. The increase in cytotoxicity after polymer-RIT conjugate pretreatment was higher for the lines overexpressing P-gp and less pronounced for those with decreased P-gp levels. Moreover, the effect of polymer conjugate containing inhibitor and DOX on the same polymer chain was lower than that of two individual polymer conjugates used sequentially. In conclusion, the polymer-RIT conjugate can significantly increase the cytotoxicity of free DOX and polymer-DOX conjugates in cells with various multidrug resistance origins and can thus be considered a suitable therapeutic enhancer of polymer prodrugs.

MiR-204 enhances mitochondrial apoptosis in doxorubicin-treated prostate cancer cells by targeting SIRT1/p53 pathway.

Chemotherapy is important for adjuvant treatment of prostate cancer. However, some cancer cells exhibited low sensitivity to chemotherapeutic agents. We are supposed to sensitize these prostate cancer cells to chemotherapeutic agents such as doxorubicin. Previous reports have suggested that microRNAs (miRNAs) regulate chemosensitivity in various cancers. In the present study, we observed that expression level of miR-204 was decreased in prostate cancer cell lines and patients’ tumors. Furthermore, we found that restore of miR-204 dramatically enhanced the cytotoxicity of doxorubicin (DOX) against prostate cancer cell lines C4-2 and LNCaP carrying wild type (WT) p53. Mechanically, miR-204 in prostate cancer cells targets SIRT1 which is a histone deacetylase, and thus decreasing deacetylation of p53. As the results, acetylated p53 induced by DOX upregulates the expression of Noxa and Puma followed by induction of mitochondrial apoptosis. These data demonstrate that restore of miR-204 in prostate cancer cells enhances the mitochondrial apoptosis induced by doxorubicin by targeting the SIRT1/p53 pathway.

Anti-angiogenic and anti-inflammatory effects of long-circulating liposomes co-encapsulating curcumin and doxorubicin on C26 murine colon cancer cells.

Emerging treatment options for colon cancer are needed to overcome the limitations regarding the side effects of current chemotherapeutics and drug resistance. The goal of this study was to assess the antitumor actions of PEGylated long-circulating liposomes (LCL) co-delivering curcumin (CURC) and doxorubicin (DOX) on murine colon carcinoma cells (C26). The cytotoxicity of CURC and DOX, administered alone or in combination, either in free or LCL form, was evaluated with regard to antiproliferative effects on C26 cells and to protumor processes that might be affected. Our results indicated that PEGylated LCL-CURC-DOX exerted strong antiproliferative effects on C26 cells, slightly exceeding those induced by free CURC-DOX, but higher than either agent administered alone in their free form. These effects of LCL-CURC-DOX were due to the inhibition of the production of angiogenic/inflammatory proteins in a NF-κB-dependent manner, but were independent of ROS production or AP-1 c-Jun activation. Notable, the anti-angiogenic actions of LCL-CURC-DOX appeared to be much stronger than those induced by the co-administration of CURC and DOX in their free form, on C26 colon cancer cells. LCL-CURC-DOX demonstrated enhanced cytotoxicity on C26 murine colon cancer cells by inhibiting the production of the majority of factors involved in tumor-associated angiogenesis and inflammation and is now being evaluated in vivo regarding its efficacy towards tumor growth in colon cancer.

Cholecalciferol-PEG ConjugateBased Nanomicelles of Doxorubicin for Treatment of Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is the leading cancer in women. Chemotherapeutic agents used for TNBC are mainly associated with dose-dependent toxicities and development of resistance. Hence, novel strategies to overcome resistance and to offer dose reduction are warranted. In this study, we designed a novel dual-functioning agent, conjugate of cholecalciferol with PEG2000 (PEGCCF) which can self-assemble into micelles to encapsulate doxorubicin (DOX) and act as a chemosensitizer to improve the therapeutic potential of DOX. DOX-loaded PEGCCF (PEGCCF-DOX) micelles have particle size, polydispersity index (PDI), and zeta potential of 40±8.7nm, 0.180±0.051, and 2.39±0.157mV, respectively. Cellular accumulation studies confirmed that PEGCCF was able to concentration-dependently enhance the cellular accumulation of DOX and rhodamine 123 in MDA-MB-231 cells through its P-glycoprotein (P-gp) inhibition activity. PEGCCF-DOX exhibited 1.8-, 1.5-, and 2.9-fold enhancement in cytotoxicity of DOX in MDA-MB-231, MDA-MB-468, and MDA-MB-231DR (DOX-resistant) cell lines, respectively. Western blot analyses showed that PEGCCF-DOX caused significant reduction in tumor markers including mTOR, c-Myc, and antiapoptotic marker Bcl-xl along with upregulation of preapoptotic marker Bax. Further, reduction in mTOR activity by PEGCCF-DOX indicates reduced P-gp activity due to P-gp downregulation as well and, hence, PEGCCF causes enhanced chemosensitization and induces apoptosis. Substantially enhanced apoptotic activity of DOX (10-fold) in MDA-MB-231(DR) cells confirmed apoptotic potential of PEGCCF. Conclusively, PEGCCF nanomicelles are promising delivery systems for improving anticancer activity of DOX in TNBC, thereby reducing its side effects and may act as a potential carrier for other chemotherapeutic agents.

Balaglitazone reverses P-glycoprotein-mediated multidrug resistance via upregulation of PTEN in a PPARγ-dependent manner in leukemia cells.

Multidrug resistance in tumor cells is still a big challenge in cancer treatment. Therefore, identification ofsafe and effective multidrug resistance-reversing compounds with minimal side effects is an important approach in cancer treatment. Here, we investigated the role and potential mechanisms of peroxisome proliferator-activated receptor γ in doxorubicin-resistant human myelogenous leukemia (K562/DOX) cells. The effect of doxorubicin on cell viability following treatment with balaglitazone, a peroxisome proliferator-activated receptor γ agonist, was evaluated using trypan blue and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Rhodamine123 assay was used to determine the activity of two common drug efflux membrane transporters P-glycoprotein and multidrug resistance protein-1. P-glycoprotein, multidrug resistance protein-1, and phosphatase and tensin homolog deleted on chromosome 10 messenger RNA/protein expression levels were measured by quantitative reverse transcription polymerase chain reaction and western blot analyses. Annexin V/fluorescein isothiocyanate assay was also employed to investigate apoptosis. We showed that balaglitazone considerably enhanced the cytotoxicity of doxorubicin. Balaglitazone also significantly downregulated P-glycoprotein expression and activity in K562/DOX cells and reduced multidrug resistance through elevation of intracellular doxorubicin in cells. Furthermore, upon balaglitazone treatment, phosphatase and tensin homolog deleted on chromosome 10 expression could be restored in K562/DOX cells in a peroxisome proliferator-activated receptor γ-dependent manner. We concluded that peroxisome proliferator-activated receptor γ agonist, balaglitazone, could reverse multidrug resistance by inducing phosphatase and tensin homolog deleted on chromosome 10 and peroxisome proliferator-activated receptor/ phosphatase and tensin homolog deleted on chromosome 10 signaling pathway. These findings suggest that targeting peroxisome proliferator-activated receptor γ might serve as an effective approach for circumventing multidrug resistance in chemotherapy of cancerous patients.

A self-assembled polyjuglanin nanoparticle loaded with doxorubicin and anti-Kras siRNA for attenuating multidrug resistance in human lung cancer

Lung cancer is a leading cause of cancer-associated mortality worldwide, which has a low survival rate. Multidrug resistance (MDR) is a major obstacle that hinders the treatment of lung cancer. Doxorubicin (DOX) is an anthracycline glycoside antibiotic, having a broad spectrum of anticancer activity against various solid tumors. Juglanin is a natural production, mainly extracted from green walnut husks of Juglans mandshurica, exhibiting various bioactivities. Here, we demonstrated that the combination of drug, gene and nanoparticle overcame MDR, inhibiting lung cancer progression. A novel nanoparticular pre-chemosensitizer was applied to develop a self-assembled nanoparticle formula of amphiphilic poly(juglanin (Jug) dithiodipropionic acid (DA))-b-poly(ethylene glycol) (PEG)-siRNA Kras with DOX in the core (DOX/PJAD-PEG-siRNA). The formed nanoparticles, appeared spherical shape, had mean particle size of 81.8 nm, and the zeta potential was −18.62 mV. The in vitro drug release results suggested that a sustained release was observed in DOX/PJAD-PEG-siRNA nanoparticles compared to the free DOX. Jug could improve the cytotoxicity of DOX to cancer cells with MDR. Oncogene, Kras, was dose-dependently reduced by treatment of DOX/PJAD-PEG-siRNA nanoparticles. Additionally, P-glycoprotein (MDR1) and c-Myc, contributing to tumor progression, were suppressed by the nanoparticles, while p53 was improved in drug-resistant cells. Colony formation analysis suggested that DOX/PJAD-PEG-siRNA nanoparticles showed the most effective role in reducing cancer cell proliferation. In vivo, DOX/PJAD-PEG-siRNA nanoparticles reduced tumor growth compared to the free DOX, accompanied with reduced KI-67 and enhanced TUNEL positive levels in drug-resistant xenografted nude mice. Thus, the findings above indicated that juglanin, as a chemosensitizer, potentiate the anti-cancer role of DOX in drug-resistant cancer cells. And the nanoparticles exhibited stronger antitumor efficiency, suggesting potential value in the treatment of lung cancer.