Doxorubicin In MCF-7 Cells Research Articles

Ozone combined with doxorubicin exerts cytotoxic and anticancer effects on Luminal-A subtype human breast cancer cell line.

We aimed to examine the potential anticancer effects of ozone applied after chemotherapeutic treatment with different concentrations of doxorubicin in Luminal-A subtype of human breast cancer cell line (MCF-7) and compare the results with effects on L929 fibroblast cell line. Both cell lines were incubated with increasing doses of doxorubicin (1-50 μM) for 24 h at 37°C. Then, half of groups were incubated with 30 μg/mL ozone for 25 min as combination groups. Cell viability was analyzed by MTT assay, apoptosis by flow cytometry, and levels of tumor necrosis factor alpha, transforming growth factor beta, and matrix metalloproteinase-2 and MMP-9 by immunocytochemistry. Doxorubicin + ozone treatment enhanced viability of L929 (p<0.01) but reduced viability of MCF-7 compared to only doxorubicin-applied cells without ozone treatment (p<0.001). This combined treatment also enhanced apoptotic effect of doxorubicin on MCF-cells (p<0.001), but not on L929. It significantly increased all protein levels of L929 compared with those of other groups (p<0.05 for tumor necrosis factor alpha and MMP-2; p<0.01 for transforming growth factor beta and MMP-9). This treatment reversed the effect of doxorubicin on tumor necrosis factor alpha levels and considerably reduced MMP-2 and MMP-9 levels of MCF-7 compared with those of control group (p<0.01 and p<0.001, respectively). Ozone treatment potentiated the apoptotic and anticancer activities of doxorubicin in MCF-7 cells and showed repairing and healing effect on healthy fibroblast cells, which were damaged from cytotoxic effects of chemotherapeutic agent. MCF-7 cells may acquire sensitivity against the doxorubicin combined with ozone treatment through activating tumor necrosis factor alpha, MMP-2, and MMP-9 expressions.

Long non-coding RNA-FOXF1 adjacent non-coding RNA as a good prognostic factor in breast cancer

Objective To test FOXF1 adjacent non-coding RNA (FENDRR) expression levels in breast cancer samples, and evaluate its effects on recurrence-free survival (RFS) in breast cancer and how FENDRR modulates drug sensitivity to doxorubicin. Methods Real-time quantitative polymerase chain reaction (Real-time PCR) and pared t test were utilized to analyze FENDRR levels in normal breast tissues and cancer tissues. Online survival analysis website was used to test the effects of FENDRR on breast cancer survival. Small interfering RNAs (siRNAs) were used to knock down FENDRR and SRB was carried out to test the response to doxorubicin. We also tested the mRNA levels of adenosine triphosphate binding cassette subfamily B member 1 (ABCB1) and multidrug resistance associated protein 1 (ABCC1) after down-regulating FENDRR. Results The FENDRR levels were lower in cancer samples than those in normal breast tissues in breast caner (1.00±0.13 vs. 2.50±0.34, t=4.528, P<0.01). RFS rate of breast cancer patients with lower levels of FENDRR was lower in all patients, the subgroups of luminal A, luminal B and basal, and patients receiving systemic treatment [P<0.01, <0.01, <0.05, <0.05 and <0.01, hazard ratio (HR)=0.67 (0.57-0.79), 0.60 (0.47-0.78), 0.70 (0.51-0.96), 0.65 (0.47-0.91) and 0.61 (0.49-0.76)]. Down-regulation of FENDRR could up-regulate the expression of ABCB1 and ABCC1, conferring resistance to doxorubicin in MCF-7 cells. Conclusion FENDRR was lower in breast cancer samples, and correlated to better survival in breast cancer. By regulating MDR-related gene expression, FENDRR modulated drug sensitivity in MCF-7 cells. Key words: Breast cancer; Long non-coding RNA; Survival; Drug resistance

Chitosan-Dextran sulfate coated doxorubicin loaded PLGA-PVA-nanoparticles caused apoptosis in doxorubicin resistance breast cancer cells through induction of DNA damage

To overcome the toxicity, pharmacokinetics and drug resistance associated with doxorubicin (DOX), a strategy was developed by encapsulating DOX- loaded-PLGA-PVA- nanoparticles within chitosan-dextran sulfate nanoparticles (CS-DS) [CS-DS-coated-DOX-loaded -PLGA-PVA-NP] and study the sensitivity against DOX- resistance- breast cancer cells (MCF-7-DOX-R). These CS-DS and PLGA-PVA double coated DOX are spherical, stable, polydispersed and have zeta potential +2.89 mV. MCF-7- DOX-R cells were derived by exposing increasing doses of DOX in MCF-7 cells. These cells were resistance to 500 nM of DOX while parental cells were susceptible at 150 nM. The double coated NP caused more cytotoxicity in cancer and MCF-7-DOX-R cells without affecting the normal cells in comparison to DOX-loaded-PLGA-PVA-NP. These NP enhances the uptake of DOX in MCF-7-DOX-R cells and caused apoptosis by increasing apoptotic nuclei, Bax/Bcl-xL ratio, cleaved product PARP-1, tumor suppressor gene p21, p53, topoisomerase inhibition activity, DNA damage and decreasing the migratory potential of cells. An increased S phase arrest was noted in DOX and DOX- loaded- PLGA-PVA-NP treated cells but reduction of S phase and simultaneous increase of Sub-G1 was observed in double coated-NP. Thus, data revealed that CS-DS- DOX- loaded PLGA-PVA- NP caused DOX-resistance cell death by inducing inhibition of topoisomerase activity followed by DNA damage.

Antiproliferative effects of isoprenoids from Sarcophyton glaucum on breast cancer MCF-7 cells

Purpose: To evaluate the anticancer activity of isoprenoids of Sarcophyton glaucum on MCF-7 cells and to investigate the potential synergistic effect of doxorubicin.Methods: Isolation and purification of isoprenoids were performed by applying different planar chromatographic methods (CC and PTLC). Further analyses of the isoprenoids by nuclear magnetic resonance (NMR) and mass spectrometry (MS) carried out to identify the compounds. Sulforhodamine- B (SRB) assay was used to determine the cytotoxic activity of the compounds against the MCF-7 human cell line. Flow cytometric analysis was used to assess their impact on cell cycle of MCF-7. Combination index (CI), when the compounds were combined with doxorubicin, was calculated to determine possible synergism. The isoprenoid compounds were also incubated at ¼ or ½ of their respective half-maximal concentration (IC50) with equimolar concentrations of doxorubicin.Results: Four known isoprenoid derivatives (1-4) were identified as 10(14)-aromadendrene (1), sarcophinediol (2), ent-deoxysarcophine (3) and sarcotrocheliol acetate (4). It was observed that cells accumulated in pre-G phase as well. CI of compound 3 with doxorubicin was 0.67 and 0.79, respectively, at ¼ and ½ of IC50, indicating overt synergism. This was confirmed by re-assessing the cell cycle stages of MCF-7 cells.Conclusion: The results indicate that compound 3 exhibits promising cytotoxicity as well as synergism with doxorubicin in MCF-7 cells. This is attributed, at least partly, to its ability to generate intercellular apoptosis induction.Keywords: Sarcophyton glaucum, Combination index, Antiproliferation, Isoprenoidal derivatives, 10(14)-Aromadendrene,Sarcophinediol, Deoxysarcophine, Sarcotrocheliol acetate, Doxorubicin

The effect of quercetin and doxorubicin combination in inhibiting resistance in mcf-7 cell

Background: Doxorubicin chemotherapy may induce the development of resistance in the cancer cells. Overexpression of P-glycoprotein (P-gp) has prominent causative role in this process. Unfortunately, many inhibitory agents do not exert satisfying clinical outcome to overcome resistance. Quercetin, a polyphenolic compound, can be developed as P-gp inhibitor due to its cytotoxic properties.Objective: To investigate the effect of quercetin and doxorubicin combination in inhibiting the development of resistance in MCF-7 cell.Methods: Doxorubicin resistant MCF-7 cell were developed from the parent MCF-7 cell by exposing to 75 nM doxorubicin for 25 days. The inhibitory effect of resistance was evaluated via exposured to 75 nM doxorubicin and 750 nM quercetin combination in the same manner with resistance induction. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) citotoxicity assay and flowcytometry assay were performed to investigate the degree of resistance and to inhibit the development of resistance.Results: The exposure of 75 nM doxorubicin in MCF-7 cells (MCF-7 cells/dox75) exhibited sensitivity significantly decrease and upregulation of P-gp expression. The combination of 750 nM quercetin and 75 nM doxorubicin (MCF-7 cells/ dox75q750) caused a significantly increase in cell sensitivity to doxorubicin (p&lt;0,05) and a decrease in P-gp expression (p&gt; 0,05).Conclusions: The exposure of 75 nM doxorubicin led to the development of doxorubicin-acquired resistance MCF-7 cell. The combination of quercetin and doxorubicin have potency to inhibit the development of doxorubicin-acquired resistance MCF-7 cell by increasing cell sensitivity and reducing P-gp expression level.Bangladesh Journal of Medical Science Vol.16(1) 2017 p.91-97

Role of autophagy and lysosomal drug sequestration in acquired resistance to doxorubicin in MCF-7 cells.

BackgroundThe roles and mechanisms involved in starvation-induced autophagy in mammalian cells have been extensively studied. However, less is known about the potential role for autophagy as a survival pathway in acquired drug resistance in cancer cells under nutrient-rich conditions.MethodsWe selected MCF-7 breast tumor cells for survival in increasing concentrations of doxorubicin and assessed whether the acquisition of doxorubicin resistance was accompanied by changes in doxorubicin and lysosome localization and the activation of autophagy, as assessed by laser scanning confocal microscopy with or without immunohistochemical approaches. The ultrastructure of cells was also viewed using transmission electron microscopy. Cellular levels of autophagy and apoptosis-related proteins were assessed by immunoblotting techniques, while protein turnover was quantified using a flux assay.ResultsAs cells acquired resistance to doxorubicin, the subcellular location of the drug moved from the nucleus to the perinuclear region. The location of lysosomes and autophagosomes also changed from being equally distributed throughout the cytoplasm to co-localizing with doxorubicin in the perinuclear region. There was an apparent temporal correlation between the acquisition of doxorubicin resistance and autophagy induction, as measured by increases in monodansylcadaverine staining, LC3-II production, and co-localization of LAMP1 and LC3-II immunofluorescence. Electron microscopy revealed an increase in cytoplasmic vacuoles containing mitochondria and other cellular organelles, also suggestive of autophagy. Consistent with this view, a known autophagy inhibitor (chloroquine) was highly effective in restoring doxorubicin sensitivity in doxorubicin-resistant cells. Moreover, this induction of autophagy correlated temporally with increased expression of the selective cargo receptor p62, which facilitates the delivery of doxorubicin-damaged mitochondria and other organelles to autophagosomes. Finally, we suggest that autophagy associated with doxorubicin resistance may be distinct from classical starvation-induced autophagy, since Beclin 1 and Atg7 expression did not change upon acquisition of doxorubicin resistance, nor did recombinant Bcl2 overexpression or an Atg7 knockdown alter doxorubicin cytotoxicity.ConclusionTaken together, our findings suggest that doxorubicin resistance in MCF-7 breast cancer cells is mediated, at least in part, by the activation of autophagy, which may be distinct from starvation-induced autophagy.

DNA-Hybrid-Gated Photothermal Mesoporous Silica Nanoparticles for NIR-Responsive and Aptamer-Targeted Drug Delivery.

Near-infrared light is an attractive stimulus due to its noninvasive and deep tissue penetration. Particularly, NIR light is utilized for cancer thermotherapy and on-demand release of drugs by the disruption of the delivery carriers. Here we have prepared a novel NIR-responsive DNA-hybrid-gated nanocarrier based on mesoporous silica-coated Cu1.8S nanoparticles. Cu1.8S nanoparticles, possessing high photothermal conversion efficiency under a 980 nm laser, were chosen as photothermal agents. The mesoporous silica structure could be used for drug storage/delivery and modified with aptamer-modified GC-rich DNA-helix as gatekeepers, drug vectors, and targeting ligand. Simultaneously, the as-produced photothermal effect caused denaturation of DNA double strands, which triggered the drug release of the DNA-helix-loaded hydrophilic drug doxorubicin and mesopore-loaded hydrophobic drug curcumin, resulting in a synergistic therapeutic effect. The Cu1.8S@mSiO2 nanocomposites endocytosed by cancer cells through the aptamer-mediated mode are able to generate rational release of doxorubicin/curcumin under NIR irradiation, strongly enhancing the synergistic growth-inhibitory effect of curcumin against doxorubicin in MCF-7 cells, which is associated with a strong mitochondrial-mediated cell apoptosis progression. The underlying mechanism of apoptosis showed a strong synergistic inhibitory effect both on the expression of Bcl-2, Bcl-xL, Mcl-1, and upregulated caspase 3/9 activity and on the expression level of Bak and Bax. Therefore, Cu1.8S@mSiO2 with efficient synergistic therapeutic efficiency is a potential multifunctional cancer therapy nanoplatform.

Gene expression alterations in chronic hypoxic MCF7 breast cancer cell line

Hypoxia plays a significant role in tumor progression and aggressiveness and implicated in resistance to radiotherapy and chemotherapy. This study aims to characterize the changes in gene expression associated with chronic hypoxia in MCF7 breast cancer cell line and identify a possible biomarker for hypoxia in breast cancer. Breast cancer cells (MCF7) were exposed to 8-hour hypoxic episodes (<1% oxygen) three times a week for a total of 38 episodes. Gene expression changes were profiled using RT- PCR array after 19 and 38 episodes of hypoxia and compared to normoxic cells. Chemoresistance of hypoxic cells toward doxorubicin was assessed using MTT cell proliferation assay. Marked gene expression changes were indentified after 19 and 38 episodes of hypoxia. Only few changes were common in both stages with most genes rebounding at the level of 38 episodes. A notable gene (HNF4A) has been up-regulated by 2 folds after 19 hypoxic shots and further up-regulated by 6.43 folds after 38 hypoxic shots. The half maximal inhibitory concentration (IC50) of doxorubicin in MCF7 cells has increased in a trend proportional to the number of hypoxic episodes then totally rebounded after incubation under normoxia for 3weeks. This study provides evidence that exposing cells to prolonged periods of hypoxia (weeks) results in different expression changes than those induced by short-term hypoxia (less than 72h).

The co-delivery of a low-dose P-glycoprotein inhibitor with doxorubicin sterically stabilized liposomes against breast cancer with low P-glycoprotein expression.

IntroductionP-glycoprotein (P-gp) inhibitors are usually used to treat tumors that overexpress P-gps. However, most common types of breast cancers, such as Luminal A, are low-P-gp expressing, at least during the initial phases of treatment. Therefore, it would be interesting to know if P-gp inhibitors are still useful in treating low-P-gp-expressing tumors.MethodsIn the study reported here, the human breast-cancer cell line MCF-7, chosen as a model of Luminal A, was found to be low-P-gp expressing. We designed a novel doxorubicin (DOX) sterically stabilized liposome system co-loaded with the low-dose P-gp inhibitor cyclosporine A (CsA) (DOX/CsA/SSL).ResultsThe co-delivery system showed good size uniformity, high encapsulation efficiency, and a desirable release profile. The cell-uptake and cytotoxicity studies demonstrated that CsA could significantly enhance the intracellular accumulation and toxicity of free DOX and the liposomal DOX in MCF-7 cells. The confocal microscopy and in vivo imaging study confirmed the intracellular and in vivo targeting effect of DOX/CsA/SSL, respectively. Finally, the in vivo study proved that DOX/CsA/SSL could achieve significantly better antitumor effect against MCF-7 tumor than controls, without inducing obvious systemic toxicity.ConclusionThis study demonstrated that the co-delivery of a low-dose P-gp inhibitor and liposomal DOX could improve the therapy of low-P-gp-expressing cancer, which is of significance in clinical tumor therapy.

Platycodin D from Platycodonis Radix enhances the anti-proliferative effects of doxorubicin on breast cancer MCF-7 and MDA-MB-231 cells.

BackgroundIt has been demonstrated that platycodin D (PD) exhibits anti-cancer activities. This study aims to investigate the anti-proliferative effects of the combination of PD and doxorubicin (DOX) on human breast cancer cells (MCF-7 and MDA-MB-231 cells).MethodsThe anti-proliferative effects of different dosages of PD, DOX, and PD + DOX on MCF-7 and MDA-MB-231 cells were determined by the MTT assay. The 10 μM PD, 5 μM DOX, and 10 μM PD + 5 μM DOX induced-protein expression of apoptosis-related molecules on MCF-7 and MDA-MB-231 cells were detected by western blot. The 10 μM PD, 5 μM DOX and 10 μM PD + 5 μM DOX-induced mitochondrial membrane potential changes on MCF-7 and MDA-MB-231 cells were stained with JC-1 before visual determination. The intracellular accumulations of DOX, induced by 10 μM PD, 5 μM DOX and 10 μM PD + 5 μM DOX, were detected by flow cytometry.ResultsPD enhanced anti-cancer activities of DOX were observed in both MCF-7 and MDA-MB-231 cell lines. Compared with mono treatment, the combined treatment increased the protein expression of cleaved poly (ADP-ribose) polymerase and decreased the mitochondrial membrane potential. The combined treatment with PD did not obviously increase the accumulation of DOX in MCF-7 cells (1.66 ± 0.13 in DOX-treated group, and 1.69 ± 0.06 in PD + DOX-treated group, P = 0.76), but it significantly increased the accumulation of DOX in MDA-MB-231 cells (1.76 ± 0.17 in DOX-treated group, 2.09 ± 0.02 in PD + DOX-treated group, P = 0.027).ConclusionThe combined treatment of DOX and PD exhibited stronger anti-proliferative effects on MCF-7 and MDA-MB-231 cells than DOX and PD treatment did.

Resveratrol reduces the hypoxia-induced resistance to doxorubicin in breast cancer cells.

Resveratrol (3,4',5-trihydroxy-trans-stilbene) is known to enhance the cytotoxicity of the anticancer drug doxorubicin. On the other hand, breast cancer MCF-7 cells acquire resistance to doxorubicin under hypoxic conditions. In this study, we investigated the effect of resveratrol on hypoxia-induced resistance to doxorubicin in MCF-7 cells. Resveratrol and its derivative 3,5-dihydroxy-4'-methoxy-trans-stilbene, but not 3,5-dimethoxy-4'-hydroxy-trans-stilbene, cancelled hypoxia-induced resistance to doxorubicin at a concentration of 10 μM. Carbonyl reductase 1 (CBR1) catalyzes the conversion of doxorubicin to its metabolite doxorubicinol, which is much less effective than doxorubicin. Hypoxia increased the expression of CBR1 at both mRNA and protein levels, and knockdown of CBR1 inhibited hypoxia-induced resistance to doxorubicin in MCF-7 cells. Knockdown of hypoxia-inducible factor (HIF)-1α repressed the hypoxia-induced expression of CBR1. Resveratrol repressed the expression of HIF-1α protein, but not HIF-1α mRNA, and decreased hypoxia-activated HIF-1 activity. Resveratrol repressed the hypoxia-induced expression of CBR1 at both mRNA and protein levels. Likewise, 3,5-dihydroxy-4'-methoxy-trans-stilbene decreased the hypoxia-induced expression of CBR1 protein, but not 3,5-dimethoxy-4'-hydroxy-trans-stilbene. Furthermore, resveratrol decreased the expression of HIF-1α protein even in the presence of the proteasome inhibitor MG132 in hypoxia. Theses results indicate that in MCF-7 cells, HIF-1α-increased CBR1 expression plays an important role in hypoxia-induced resistance to doxorubicin and that resveratrol and 3,5-dihydroxy-4'-methoxy-trans-stilbene decrease CBR1 expression by decreasing HIF-1α protein expression, perhaps through a proteasome-independent pathway, and consequently repress hypoxia-induced resistance to doxorubicin.

Abstract B45: Gene expression alteration in chronic hypoxic MCF7 breast cancer cell line.

Abstract Background: As solid tumors outgrow their vasculature, areas of low oxygen concentration arise where the oxygen demand surpasses supply. Hypoxia plays a significant role in tumor progression and aggressiveness. It is also implicated in therapy resistance to radiotherapy and chemotherapy. Objective: The aim of this study is to characterize the changes in gene expression associated with chronic hypoxia in MCF7 breast cancer cell line with the goal of identifying a possible biomarker for hypoxia in breast cancer. Methodology: Breast cancer cells (MCF7) were exposed to 8-hour hypoxic episodes (&amp;lt;1% oxygen) three times a week for a total of 38 episodes. The alterations in gene expression were measured using the real-time based PCR array technology after 19 and 38 episodes of hypoxia and compared to normoxic cells. Chemoresistance of hypoxic cells toward doxorubicin was assessed using MTT cell proliferation assay. Results: Marked gene expression changes were indentified after 19 and 38 episodes of hypoxia. Only few changes were common in both stages with most genes rebounding at the level of 38 episodes. A notable gene (HNF4A) has been up-regulated by 2 folds after 19 hypoxic shots and further up-regulated by 6.43 folds after 38 hypoxic shots. The half maximal inhibitory concentration (IC50) of doxorubicin in MCF7 cells has increased by 1.5 folds after 19 episodes of hypoxia and quadrupled after 35 episodes compared to normoxic cells. Conclusions: This study provide evidence that exposing cells to prolonged periods of hypoxia (weeks) results in different expression changes than those induced by short-term hypoxia (&amp;lt;72 hours). It also confirms induction of chemoresistance by chronic hypoxia. Finally, it proposes HNF4A as a potential biomarker for hypoxia in breast cancer and as a main player in the cellular response to chronic hypoxia. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B45. Citation Format: Malek A. Zihlif, Feda’ Hisham Hamdan. Gene expression alteration in chronic hypoxic MCF7 breast cancer cell line. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B45.

Abstract 1827: HnRNP I interacts with lncRNA UCA1 and regulates its stability.

Abstract Background: The human genome also makes a large number of non-coding RNAs including long non-coding RNAs (lncRNAs) and microRNAs in addition to protein-coding genes. While microRNAs are well characterized, little is known about lncRNAs. Emerging evidence has implicated lncRNAs in gene regulation; and they are often aberrantly expressed in a variety of human diseases, in particular cancer. The heterogeneous nuclear ribonucleoprotein I (hnRNP I) is a member of the large hnRNP family and has been implicated in mRNA splicing, stability and translational regulation of certain RNA transcripts. During screening for lncRNA-interacted proteins, we identified hnRNP I as a binding partner for UCA1. However, it remains unclear how hnRNP I interacts with UCA1 and whether such an interaction impacts UCA1-mediated cell growth and responsiveness to anti-cancer drugs. Methods: To determine cell growth and response to doxorubicin, we performed MTT assays as well as cell counting assays. Protein levels from treated cells were analyzed by western blot. Real-time RT-PCR was used to determine relative expression of genes. Interaction between hnRNP I and UCA1 was confirmed by RNA co-immunoprecipitation and RNA pulldown. RNA stability was determined by treating MCF-7 cells with actinomycin D, followed by real-time RT-PCR. hnRNP I was knock down by transient transfection of hnRNP I siRNAs. Results: We found that UCA1 induced proliferation and increased resistance to doxorubicin in MCF-7 cells. RNA pulldown assays revealed that UCA1 RNA directly interacted with hnRNP I. This interaction was further confirmed by RNA immunoprecipitation by hnRNP I antibody. Real-time RT-PCR revealed that knockdown of hnRNP I by RNAi reduced the level of UCA1 in MCF-7 cells and it also repressed the induction of UCA1 by doxorubicin. Further experiments suggested that hnRNP I impacts the UCA1 stability. We showed that half-life of UCA1 was about 12 h but was decreased to about 6 h in the presence of hnRNP I siRNAs. We further showed that the phosphorylated form of hnRNA I, predominantly in the cytoplasm, was a major form that interacts with UCA1. Conclusion: Taken together, these results suggest that hnRNP I plays a role in regulation of the stability of UCA1. Since previous work implicates the involvement of UCA1 in tumor cell growth and chemoresistance, a better understanding of the underlying mechanism will provide new insight of targeting UCA1 in cancer therapy. Citation Format: Jianguo Huang, Yin-Yuan Mo. HnRNP I interacts with lncRNA UCA1 and regulates its stability. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1827. doi:10.1158/1538-7445.AM2013-1827

Lipotropes enhance the anti-proliferative effect of chemotherapeutic drugs in MCF-7 human breast cancer cells

Increasing evidence indicates that dietary intake of methyl nutrients is associated with the risk of breast cancer. Lipotropes are methyl group-containing essential nutrients (methionine, choline, folate and vitaminB12) which play key roles in one-carbon metabolism; however, little is known about the implications of lipotropes in possible tumor-suppressive effects with chemotherapeutic drugs for breast cancer. In the present study, we investigated the invitro effects of lipotropes on cell growth and apoptosis of MCF-7 human breast cancer cells. Cells were cultured and treated with lipotropes, and cell proliferation, apoptosis and gene expression were determined. Also, the possible synergistic effects of lipotropes with anticancer drugs, the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA) and doxorubicin (DOX), were examined. Lipotropes significantly reduced the growth of MCF-7 cells and increased apoptosis as well as upregulation of caspase-3 and tumor protein 53 (p53) enzyme activities. Gene transcription, as measured by quantitative real-time PCR, revealed a significant increase of p53 mRNA in MCF-7 cells treated with lipotropes, but there were no differences in two drug-resistant related genes. Moreover, lipotropes showed significant additive effects with SAHA and DOX on cell growth inhibition. These results suggest that lipotropes induce apoptosis, inhibit cell growth, and display anti-proliferative effects with SAHA and DOX in MCF-7 cells. Owing to the tumor-suppressive effects observed, lipotropes in combination with chemotherapeutic drugs may be tested further in animal models as potential therapeutic agents for reducing breast cancer risk.

Synergistic anti-cancer activity of the combination of dihydroartemisinin and doxorubicin in breast cancer cells

BackgroundDihydroartemisinin (DHA) exhibits potent anti-malarial and anti-cancer activities. This study aimed to investigate the anti-proliferative effects of a combination of DHA and doxorubicin (DOX) on human breast cancer cells. MethodsMTT assay and the combination index (CI) were used to show the anti-proliferative effects and calculate the synergism potential, respectively. Flow cytometry assay was used to detect apoptosis and the intracellular accumulation of DOX. JC-1 staining was used to determine the mitochondrial membrane potential. Western blot analysis was used to detect the protein expression of some apoptosis-related molecules. ResultsAsynergistic anti-proliferative effect was found, and the enhanced anti-cancer activity was observed to be accompanied by the prompt onset of apoptosis in MCF-7 cells. The combinative treatment remarkably decreased the mitochondrial membrane potential and activated caspase cascades more than the mono-treatment. Pretreatment with DHAalso did not influence the accumulation of DOX in MCF-7 cells. ConclusionThis study presented a new opportunity to enhance the effectiveness of future treatment regimens of breast cancer using DOX.

Octreotide-Modified N-Octyl-O, N-Carboxymethyl Chitosan Micelles as Potential Carriers for Targeted Antitumor Drug Delivery

Octreotide (OCT) was recently found to have high binding affinity to the positive tumor cells of somatostatin receptors (SSTRs). In this study, octreotide-Phe-polyethylene glycol-stearic acid was first successfully synthesized and used as a targeting molecule for N-octyl-O, N-carboxymethyl chitosan (OCC). Doxorubicin (DOX) was loaded into OCT-modified OCC micelles (DOX-OCC-OCT). The drug-loaded micelles obtained exhibited spherical shape, small particle sizes, and negative zeta potentials. The cytotoxicity of DOX-OCC-OCT micelles against MCF-7 cells (SSTRs expressing) was found to significantly increase with the increased amount of OCT modification, whereas no significant difference was observed against WI-38 cells (no SSTRs expressing). Results of flow cytometry, fluorescence microscopy, and confocal laser scanning microscopy confirmed that DOX-OCC-OCT micelles could remarkably increase the uptake of DOX in MCF-7 cells. All the results indicated that OCC-OCT micelles may be a promising intracellular targeting carrier for efficient delivery of antitumor drugs into tumor cells.

A Novel Group of Genes Regulates Susceptibility to Antineoplastic Drugs in Highly Tumorigenic Breast Cancer Cells

Doxorubicin is an anthracycline antibiotic used for cancer chemotherapy. The utility of doxorubicin is limited by its inability to kill all of the cells within a tumor and by resistant cells emerging from the treated population. We have screened for genes that regulate doxorubicin susceptibility in highly tumorigenic breast cancer cells by cDNA microarray and RNA interference (RNAi) analysis, and we have identified genes associated with both proliferation and cell cycle arrest after doxorubicin treatment. We confirmed that MDA-MB-231 cells treated with doxorubicin induce the expression of carbonic anhydrase II (CAII), inhibitor of differentiation/DNA binding 2 (Id2), activating transcription factor 3 (Atf3), and the phosphatidylinositol 3-kinase 55-kDa regulatory subunit p55PIK. These genes were induced at different times and with varying specificities to different chemotherapeutic drugs. In addition to being induced at the transcriptional level, the CAII and clusterin proteins were elevated after doxorubicin treatment. CAII, Id2, p55PIK, and clusterin were not altered by doxorubicin in MCF-7 cells, a weakly tumorigenic cell line used in previous studies of doxorubicin-regulated gene expression. By inhibiting gene expression using RNAi, we found that CAII and clusterin increase cell survival after doxorubicin treatment, whereas Id2 increases susceptibility to doxorubicin. Our results support a model in which highly tumorigenic breast cancer cells induce a transcriptional response to doxorubicin that is distinct from less malignant cells. The induced genes regulate drug susceptibility positively and negatively and may be novel targets for therapeutic intervention.