• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.36-42
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• 2017

In this work, we isolated a surface layer protein (SLP) from a Bacillus thuringiensis (Bt) strain to evaluate it cytotoxic effects against MDA-MB-231 human breast cancer cells. AP11 was selected from a g roup of Bt strains using SLP olig onucleotides developed from Bacillus conserved regions. The AP11 strain was grown in Luria Bertani medium until the late exponential phase; an 86 kDa protein was extracted using 5 M LiCl and identified by liquid chromatography-tandem mass spectrometry. It corresponded to a multispecies SLP highly similar to previously described SLPs in Bt. The MDA-MB-231 breast cancer cells $LC_{50}$ was obtained using $0.25{\mu}g/ml$ of the isolated SLP. HaCat non-cancerous cells presented 90% survival using the same protein concentration. Our data suggest that SLP cytotoxicity against MDA-MB-231 could be induced by an interaction with the CDH11 cell membrane receptor.

• Natural Product Sciences
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• v.28 no.3
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• pp.115-120
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• 2022

Ten compounds, consisting of neoflavonoids (1-5), isoflavonoids (6 and 7), flavanone (8), and chalcones (9 and 10) were isolated from the ethyl acetate and n-butanol-soluble fractions of the heartwood of Dalbergia melanoxylon. The chemical structures were identified on the basis of spectroscopic evidence and compared to previously reported spectra. Compounds 1-10 were evaluated for cytotoxicity against HCT116 human colorectal cancer, MDA-MB-231 human metastatic breast cancer, and A2058 human melanoma cell lines. Among them, compounds 3 and 10 showed the strongest cytotoxic activity with IC₅₀ values of 11.92±1.07 μM, 10.83±1.02 μM, and 14.37±1.02 μM, 13.62±1.09 μM against HCT116 and MDA-MB-231 cell lines, respectively. Compounds 9 and 10 also had cytotoxic activity with IC₅₀ values of 13.49±1.18 μM and 9.82±0.91 μM against A2058 cell lines, respectively. To the best our knowledge, compounds 2 and 5-10 were isolated from this source for the first time.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.10
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• pp.4255-4259
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• 2014

Lactobacilli are probiotics shown to have antitumor activities. In addition, they can regulate gene expression through epigenetic mechanisms. In this study, we aimed to assess anti tumor activities of Lactobacillus acidophilus and Lactobacillus crispatus on the MDA-MB-231 breast cancer cell line. The effects of culture supernatants were determined by MTT [3-(4,5-dimethylthiazol-2-y-2,5-diphenyltetrazolium bromide] assay. Changes in expression of 5 cancer-testis antigens (CTAs), namely AKAP4, ODF4, PIWIL2, RHOXF2 and TSGA10, were analyzed by quantitative real time RT-PCR. The culture supernatants of the 2 lactobacilli inhibited MDA-MB-231 cell proliferation. In addition, transcriptional activity of all mentioned CTAs except AKAP4 was significantly decreased after 24 hour treatment with culture supernatants. This study shows that Lactobacillus acidophilus and Lactobacillus crispatus have antiproliferative activity against MDA-MB-231 cells. In addition, these lactobacilli could decrease transcriptional activity of 4 CTAs. Previous studies have shown that expression of CTAs is epigenetically regulated, so it is possible that lactobacilli cause this expression downregulation through epigenetic mechanisms. As expression of CTAs in cancers is usually associated with higher grades and poor prognosis, downregulation of their expression by lactobacilli may have clinical implications.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3211-3217
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• 2014

Background: The current study investigated the effects of Piper longumine on radio-sensitization of human breast cancer MDA-MB-231 cells and underlying mechanisms. Materials and Methods: Human breast cancer MDA-MB-231 cells were cultured in vitro and those in logarithmic growth phase were selected for experiments divided into four groups: control, X-ray exposed, Piper longumine, and Piper longumine combined with X-rays. Conogenic assays were performed to determine the radio-sensitizing effects. Cell survival curves were fitted by single-hit multi-target model and then the survival fraction (SF), average lethal dose ($D_0$), quasi-threshold dose ($D_q$) and sensitive enhancement ratio (SER) were calculated. Cell apoptosis was analyzed by flow cytometry (FCM). Western blot assays were employed for expression of apoptosis-related proteins (Bc1-2 and Bax) after treatment with Piper longumine and/or X-ray radiation. The intracellular reactive oxygen species (ROS) level was detected by FCM with a DCFH-DA probe. Results: The cloning formation capacity was decreased in the group of piperlongumine plus radiation, which displayed the values of SF2, D0, Dq significantly lower than those of radiation alone group and the sensitive enhancement ratio (SER) of D0 was1.22 and 1.29, respectively. The cell apoptosis rate was increased by the combination treatment of Piper longumine and radiation. Piper longumine increased the radiation-induced intracellular levels of ROS. Compared with the control group and individual group, the combination group demonstrated significantly decreased expression of Bcl-2 with increased Bax. Conclusions: Piper longumine at a non-cytotoxic concentration can enhance the radio-sensitivity of MDA-MB-231cells, which may be related to its regulation of apoptosis-related protein expression and the increase of intracellular ROS level, thus increasing radiation-induced apoptosis.

• BMB Reports
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• v.46 no.1
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• pp.59-64
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• 2013

Signal transducer and activator of transcription 3 (STAT3) and telomerase are considered attractive targets for anticancer therapy. The in vitro anticancer activity of the gold(I) compound auranofin was investigated using MDA-MB 231 human breast cancer cells, in which STAT3 is constitutively active. In cell culture, auranofin inhibited growth in a dose-dependent manner, and N-acetyl-L-cysteine (NAC), a scavenger of reactive oxygen species (ROS), markedly blocked the effect of auranofin. Incorporation of 5-bromo-2'-deoxyuridine into DNA and anchorage-independent cell growth on soft agar were decreased by auranofin treatment. STAT3 phosphorylation and telomerase activity were also attenuated in cells exposed to auranofin, but NAC pretreatment restored STAT3 phosphorylation and telomerase activity in these cells. These findings indicate that auranofin exerts in vitro antitumor effects in MDA-MB 231 cells and its activity involves inhibition of STAT3 and telomerase. Thus, auranofin shows potential as a novel anticancer drug that targets STAT3 and telomerase.

• Annals of Surgical Treatment and Research
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• v.95 no.5
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• pp.240-248
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• 2018

Purpose: This study aimed to validate the synergistic effect of ABT-737 on docetaxel using MDA-MB-231, a triple negative breast cancer (TNBC) cell line overexpressing B-cell lymphoma-2 (Bcl-2). Methods: Western blot analysis was performed to assess expression levels of Bcl-2 family proteins and caspase-related molecules. Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle distribution was determined by flow cytometry analysis. Benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethylketone (z-VAD-fmk) was used for pretreatment to assess the role of caspases. Results: Cell viability of MDA-MB-231 after combination treatment with ABT-737 and docetaxel was significantly lower than that after docetaxel or ABT-737 monotherapy based on MTT assay (both P < 0.001), with a combination index of 0.41. The proportion of sub-G1 population after combination treatment was significantly higher than that after docetaxel or ABT-737 monotherapy (P = 0.001, P = 0.003, respectively). Pretreatment with z-VAD-fmk completely restored cell viability of MDA-MB-231 from apoptotic cell death induced by combination therapy (P = 0.001). Although pro-caspase-8 or Bid did not show significant change in expression level, pro-casepase-9 showed significantly decreased expression after combination treatment. Cleaved caspase-3 showed increased expression while poly (ADP-ribose) polymerase cleavage was induced after combination treatment. However, hypoxia-inducible factor 1-alpha and aldehyde dehydrogenase 1 totally lost their expression after combination treatment. Conclusion: Combination of ABT-737 with docetaxel elicits synergistic therapeutic effect on MDA-MB-231, a TNBC cell line overexpressing Bcl-2, mainly by activating the intrinsic pathway of apoptosis. Therefore, adjunct of ABT-737 to docetaxel might be a new therapeutic option to overcome docetaxel resistance of TNBCs overexpressing Bcl-2.

• Journal of Pharmacopuncture
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• v.22 no.1
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• pp.28-34
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• 2019

Background: Breast cancer is a complex, heterogeneous disease and one of the most common malignancies in women worldwide. The efficacy of chemotherapy as an important breast cancer treatment option has been severely limited because of the inherent or acquired resistance of cancer cells. The molecular chaperone heat shock protein 90 (HSP90) upregulated in response to cellular stress is required for functions such as conformational maturation, activation and stability in more than 200 client proteins, mostly of the signaling type. In this study, the expression of HSP90 isoforms including $HSP90{\alpha}$ and $HSP90{\beta}$ in breast cancer cell lines before and after treatment with doxorubicin (DOX) was assessed. Material and Methods: The cell cytotoxicity of DOX in MDA-MB-231 and MCF-7 cell lines was determined using the MTT assay. immunofluorescence and western blotting techniques were used to determine the expression of $HSP90{\beta}$ in the cell lines before and after DOX treatment. Immunofluorescence was also conducted to ascertain the expression of $HSP90{\alpha}$. Results: The MTT assay results showed that the MDA-MB-231 cells ($IC_{50}=14.521{\mu}M$) were more sensitive than the MCF-7 cells ($IC_{50}=16.3315{\mu}M$) to DOX. The immunofluorescence results indicated that the expression of $HSP90{\alpha}$ in both cell lines decreased after exposure to DOX. The western blot and immunofluorescence analyses showed that $HSP90{\beta}$ expression decreased in the MCF-7 cells but increased in the MDA-MB-231 cells after DOX treatment. Conclusion: The obtained results suggested that $HSP90{\alpha}$ and $HSP90{\beta}$ expression levels were reduced in the MCF-7 cells after exposure to DOX. In the MDA-MB-231 cells, $HSP90{\alpha}$ expression was reduced while $HSP90{\beta}$ was found to be overexpressed following DOX treatment.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2385-2392
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• 2012

The lack of effective treatment targets for triple-negative breast cancers make them unfitted for endocrine or HER2 targeted therapy, and their prognosis is poor. Transcription factor ER81, a downstream gene of the HER2, is highly expressed in breast cancer lines, breast atypical hyperplasia and primary breast cancers including triple-negative examples. However, whether and how ER81 affects breast cancer carcinogenesis have remained elusive. We here assessed influence on a triple-negative cell line. ER81-shRNA was employed to silence ER81 expression in the MDA-MB-231 cell line, and MTT, colony-forming assays, and flow cytometry were used to detect cell proliferation, colony-forming capability, cell cycle distribution, and cell apoptosis in vitro. MDA-MB-231 cells stably transfected with ER81-shRNA were inoculated into nude mice, and growth inhibition of the cells was observed in vivo. We found that ER81 mRNA and protein expression in MDA-MB-231 cells was noticeably reduced by ER81-shRNA, and that cell proliferation and clonality were decreased significantly. ER81-shRNA further increased cell apoptosis and the residence time in $G_0/G_1$ phase, while delaying tumor-formation and growth rate in nude mice. It is concluded that ER81 may play an important role in the progression of breast cancer and may be a potentially valuable target for therapy, especially for triple negative breast cancer.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.380-382
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• 2016

Chungkookjang, fermented soybeans, contains diverse peptides produced during fermentation. Fermented soybean extracts containing the peptides can affect cellular signal transduction. Proliferation of human breast cancer MDA-MB-231 cells were repressed dependent on concentrations of fermented soybean extracts. Since fermented soybean extracts inhibited breast cancer cell's growth, and inflammation is related to cancer, it is determined whether it can suppress inflammatory $TNF{\alpha}$ expression. $TNF{\alpha}$ expression in MDA-MB 231 cells treated with fermented soybean extracts was repressed by that extracts. $TNF{\alpha}$ inhibitors were developed as drugs for autoimmune diseases. Since fermented soybean extracts suppressed $TNF{\alpha}$ expression, it can be developed as those drugs.

• KSBB Journal
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• v.31 no.1
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• pp.52-57
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• 2016

Mutant p53 (R280K) is highly expressed in MDA-MB-231 triple-negative human breast cancer cells. Currently, we reported the role of mutant p53-R280K in mediating the survival of MDA-MB-231 cells in vitro. The present study was undertaken to determine whether mutant p53-R280K affects breast cancer cell growth in vivo. To this end, we used small interfering RNA to knockdown the level of mutant p53-R280K in MDA-MB-231 cells. Silencing of mutant p53-R280K in MDA-MB-231 cells causes substantial tumor regression of established xenografts in vivo. In xenograft model for breast cancer, silencing of mutant p53-R280K in MDA-MB-231 cells significantly inhibited the tumor growth. Moreover, TUNEL assay showed more occurrence of apoptotic cells in mutant p53-R280K silenced tumors compared to control. Our data indicate that mutant p53-R280K has an important role in mediating tumor growth of MDA-MB-231 cells in vivo. Taken together, this study suggests that endogenous mutant p53-R280K could be used as a therapeutic target for breast cancer cells harboring this TP53 missense mutation.