Bcap-37 Cells Research Articles

Elucidating respective functions of two domains BIR and C-helix of human IAP survivin for precise targeted regulating mitotic cycle, apoptosis and autophagy of cancer cells.

Survivin was the smallest member of the IAP family, which was over expressed in many different cancers, and considered to be a promising hot target for cancer therapy, and our previous study demonstrated that multiple dominant negative mutants from full-length survivin could have many complex effects on cancer cells, such as cell cycle, apoptosis, and autophagy. But it was not yet known what role the two main domains played in those functions, which would be very important for the design of targeted anticancer drugs and for the interpretation of their molecular mechanisms. In this study, based on preparation the two parts (BIR domain and CC domain) of survivin by genetic engineering and cell characterization assay, we discovered that BIR (T34A)-domain peptide could inhibit Bcap-37 cells growth in a dose- and time-dependent manner, increase the proportion of G2/M phase, and induce caspase-dependent apoptosis via the mitochondrial pathway. While CC (T117A)-domain peptide increased the proportion of S-phase cells and increased the level of the autophagy marker protein LC3B significantly. These further experiments confirmed that TAT-BIR (T34A) peptide could be used to inhibit cell proliferation, promote apoptosis, and block mitosis, and TAT-CC (T117A) peptide showed mainly to promote autophagy, process of DNA replication, and mitosis to breast cancer cells. This research will lay the foundation for interpreting the multifunction mechanism of survivin in cell fates, further make senses in developing the anticancer drugs targeting it precisely and efficiently.

Downregulation of Cohesin Loading Factor Nipped-B-Like Protein (NIPBL) Induces Cell Cycle Arrest, Apoptosis, and Autophagy of Breast Cancer Cell Lines.

BackgroundThe cohesin loading factor, nipped-B-like protein (NIPBL), is also known as the sister chromatid cohesion 2 (SCC2) human homolog. Recently, we have studied the role of expression levels of NIPBL in cell proliferation and chemotherapy resistance of non-small cell lung cancer (NSCLC) cells in vitro. The aim of this study was to investigate the effects of expression of the cohesin loading factor, NIPBL, on the cell cycle, apoptosis, and autophagy of breast cancer cell lines in vitro.Material/MethodsExpression levels of the NIPBL in the breast cancer cell lines, MCF7, Bcap37, MDA-MB 453 and MDA-MB 231, were measured using Western blot and flow cytometry. Small interfering RNA (si-RNA) was used to study the biological functions of NIPBL. The cell counting kit-8 (CCK-8) assay and the colony formation assay were used to measure cell proliferation; the wound scratching assay and transwell chamber assay were used to investigate cell invasion and migration.ResultsNIPBL gene and protein expression were upregulated in the MCF7 and Bcap37 cells; si-NIPBL transfection inhibited cell proliferation, invasion, and migration of breast cancer cells. Downregulation of NIPBL arrested cells in the G0/G1 phase of the cell cycle and induced apoptosis and autophagy of breast cancer cells through the caspase3 and mammalian target of rapamycin (mTOR) signaling pathways.ConclusionsDownregulation of cohesin loading factor NIPBL arrested breast cancer cells in vitro in the G0/G1 phase of the cell cycle and induced apoptosis and autophagy.

KLF4 overcomes tamoxifen resistance by suppressing MAPK signaling pathway and predicts good prognosis in breast cancer

Tamoxifen resistance represents a daunting challenge to the successful treatment for breast cancer. Krüppel-like factor 4 has critical roles in the development and progression of breast cancer, but its expression, function and regulation in the efficacy of TAM therapy in breast cancer have yet to be investigated. Here, we examined the clinical significance and biologic effects of KLF4 in breast cancer. Firstly, higher expression of KLF4 correlated with increased TAM sensitivity in breast cancer cells, and analysis of GEO datasets indicated that KLF4 expression was positively correlated with ERα and enhanced expression of KLF4 sensitized breast cancer patients to endocrine therapy. Knockdown of KLF4 in MCF-7 and BCAP37 cells led to increased TAM resistance, while ectopic KLF4 expression promoted the responsiveness to TAM in T47D and TAM-resistant MCF-7/TAM cells. Secondly, ectopic KLF4 overexpression suppressed MCF-7/TAM cell growth, invasion and migration. Moreover, KLF4 expression was down-regulated in breast cancer tumor tissues and high expression of KLF4 was associated with favorable outcomes. Mechanistically, KLF4 may enhance the responsiveness of breast cancer cells to TAM through suppressing mitogen-activated protein kinase (MAPK) signaling pathway. We found that ERK and p38 were more activated in MCF-7/TAM compared with MCF-7, and treatment with MAPK-specific inhibitors significantly suppressed cell viability. Knockdown of KLF4 activated ERK and p38 and drove MCF-7 cells to become resistant to TAM. Conversely, overexpression of KLF4 in MCF-7/TAM cells suppressed ERK and p38 signaling and resulted in increased sensitivity to TAM. Therefore, our findings suggested that KLF4 contributed to TAM sensitivity in breast cancer via phosphorylation modification of ERK and p38 signaling. Collectively, this study highlighted the significance of KLF4/MAPK signal interaction in regulating TAM resistance of breast cancer, and suggested that targeting KLF4/MAPK signaling may be a potential therapeutic strategy for breast cancer treatment, especially for the TAM-resistant patients.

Cytotoxic lignans from the barks of Juglans mandshurica

Phytochemical investigation of the barks of Juglans mandshurica Maxim led to the isolation, purification, and identification of one new lignan named Juglansol A (1), along with nine known compounds (2–10). Their structures were determined by the results of UV, IR, CD, HRESIMS, 1D, and 2D NMR spectroscopic analysis. Compounds 1–10 were evaluated for their cytotoxicities against A549, HepG2, Hep3B, Bcap-37, and MCF-7 cell lines. The results showed that compound 2 possessed stronger cytotoxicities against the tested tumor cell lines compared with positive control 5-fluorouracil.

PH-sensitive pHluorins as a molecular sensor for in situ monitoring of enzyme-catalyzed prodrug activation.

This work examines the feasibility of using a pH-sensitive fluorescent protein as a molecular reporter for enzyme-catalyzed prodrug activation reaction. Specifically, a ratiometric pHluorins was examined for detection of the activity of horseradish peroxidase (HRP) for the activation of indole-3-acetic acid. The pHluorins and HRP were conjugated chemically, forming a biocatalyst with a self-reporting function. Results showed that the characteristic fluorescence intensity ratio of the conjugate shifted from 1.47 to 1.40 corresponding to the progress of the prodrug activation reaction. The effectiveness of applying the conjugate for inhibition of the growth of Bcap-37 cells was also demonstrated simultaneously with reaction monitoring. The results reveal a very promising approach to realizing in situ monitoring of enzyme activities based on pH shifting for enzyme-based prodrug therapy applications.

Evidence of drug-response heterogeneity rapidly generated from a single cancer cell.

One cancer cell line is believed to be composed of numerous clones with different drug sensitivity. We sought to investigate the difference of drug-response pattern in clones from a cell line or from a single cell. We showed that 22 clones derived from 4T1 cells were drastically different from each other with respect to drug-response pattern against 11 anticancer drugs and expression profile of 19 genes associated with drug resistance or sensitivity. Similar results were obtained using daughter clones derived from a single 4T1 cell. Each daughter clone showed distinct drug-response pattern and gene expression profile. Similar results were also obtained using Bcap37 cells. We conclude that a single cancer cell can rapidly produce a population of cells with high heterogeneity of drug response and the acquisition of drug-response heterogeneity is random.

Identification and analysis of the expression of microRNA from lactating and nonlactating mammary glands of the Chinese swamp buffalo

To study the role of microRNA (miR) in the lactation physiology of water buffalo, 2 multiparous dairy buffaloes (including an 8-yr-old buffalo that had been lactating for 3 mo, as well as a 10-yr-old nonlactating, nonpregnant buffalo) were used for miR library construction. The profile of differentially expressed miR in lactating and nonlactating mammary gland tissues of these water buffalo were investigated using Illumina-Solexa high-throughput sequencing technology (Illumina, San Diego, CA). The data identified 259 miR families, 359 mature miR, 363 pre-miR, 230 novel buffalo miR, and 5 buffalo-specific miR that were expressed in mammary tissues. Some highly significantly differentially expressed miR were explored, including bbu-miR-497, bbu-miR-30a-5p, bbu-miR-148a, bbu-miR-29a, bbu-miR-125a, bbu-miR-125b, and bbu-miR-103. The expression patterns of 18 miR were confirmed by quantitative real-time PCR in both tissues, and the expression of bbu miR-103 and novel miR-57 constituted the largest differences between lactating and nonlactating tissues. Further functional analysis indicated that the overexpression or suppression of miR-103 in buffalo mammary epithelial cells downregulated or upregulated the expression of pantothenate kinase 3, and also significantly increased the transcription factor steroid regulatory element binding protein, followed by the acceleration of de novo synthesis of fatty acids by upregulation of acetyl coenzyme A carboxylase α expression. The expression levels of 34 predicted target genes of novel-miR-57 in lactating and nonlactating mammary gland tissues were all analyzed by quantitative real-time PCR. Finally, only the expression of docking protein 4 could be upregulated or downregulated selectively by bbu-novel-miR-57 in buffalo mammary epithelial cells and the Bcap-37 cell line. This study provides an overview of the miR expression profile of water buffalo and the interaction between some key miR and their target genes, which may improve understanding of the important roles of miR in buffalo milk fat synthesis.

SYP-5, a novel HIF-1 inhibitor, suppresses tumor cells invasion and angiogenesis

Hypoxia-inducible factor-1 (HIF-1) plays an essential role in carcinogenesis. The overexpression of HIF-1 induced by hypoxia is closely associated with metastasis, poor prognosis and high mortality. In this study, a novel HIF-1 inhibitor SYP-5 was first observed by the luciferase reporter assay. Western blots results showed SYP-5 inhibited hypoxia-induced upregulation of HIF-1. Moreover, the proteins of vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMP)-2 that are targets of HIF-1, were down-regulated by SYP-5. Furthermore, in the tube formation assay, SYP-5 suppressed angiogenesis induced by hypoxia and VEGF in vitro. Additionally, using Transwell and RTCA assays, we found that SYP-5 also retarded the Hep3B and Bcap37 cells migration and invasion induced by hypoxia and FBS. Last, we also detected the upstream pathways related to HIF-1 and found both PI3K/AKT and MAPK/ERK were involved in the SYP-5 mediated invasive inhibition of Bcap37 cells. These results indicates that SYP-5 inhibits tumor cell migration and invasion, as well as tumor angiogenesis, which are mediated by suppressing PI3K/AKT- and MAPK/ERK-dependent HIF-1 pathway. It suggests that SYP-5 might be a potential HIF-1 inhibitor as an anticancer agent.

Antioxidant and cytotoxic lignans from the roots of Bupleurum chinense

In the search for biologically active compounds from the roots of Bupleurum chinense D C., phytochemical investigation of its ethanol extract led to the isolation and identification of a new 8-O-4′ neolignan glucoside, saikolignanoside A (1), along with eight known lignans (2–9). Their structures were determined on the basis of IR, UV, HRESIMS, and NMR spectroscopic analyses. The antioxidant and cytotoxic effects of isolated compounds were evaluated in vitro. The isolated compounds (IC50 > 200 μM) did not display 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Whereas compounds 1–2, 5, 7, and 9 exhibited potent 2, 2′-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging properties with IC50 values ranging from 8.34 to 15.24 μM, while compounds 3–4, 6, 8 showed moderate properties. In addition, all compounds were evaluated for cytotoxicities against A549, HepG2, U251, Bcap-37, and MCF-7 cell lines. Compounds 5 and 9 (IC50 < 51.62 μM) possessed stronger cytotoxic activities against all the tested tumor cell lines, compared with the positive control 5-Fluorouracil.

Inhibition of ERα/ERK/P62 cascades induces "autophagic switch" in the estrogen receptor-positive breast cancer cells exposed to gemcitabine.

Several clinical trials revealed that estrogen receptor (ER) status had relevance to the response of mammary malignancy to chemotherapy. Autophagy has emerged as an important cellular mechanism of tumor cells in response to anticancer therapy. The aim of this study is to investigate whether gemcitabine induces autophagy, and more importantly, whether such autophagy is functional relevant to the therapeutic effects of gemcitabine in breast cancer cells in relation to the ER status. In our study, autophagy was induced both in ER+ MCF-7 and ER− MDA-MB-231 cells by gemcitabine markedly, while the autophagy plays distinct roles – cytoprotective in ER− MDA-MB-231 and cytotoxic in ER+ MCF-7 cells. Gemcitabine treatment leads to the activation of ERα-ERK-P62 signal pathway in MCF-7 cells which may augment the autophagic degradation, thus results in the excessive activation of autophagy and irreversible autophagic cell death eventually. Inhibition of ERα-ERK-P62 cascades in MCF-7 cells by small interfering RNA or PD98059 impairs the autophagic degradation, and leads to “autophagic switch” – from cytotoxic autophagy to cytoprotection. Moreover, stable overexpression of ERα in the ER− BCap37 breast cancer cell line enhances the gemcitabine-induced autophagy flux and switches the autophagic cytoprotection in ER− BCap37 to cytotoxicity effect in ER+ BCap37 cells. Our study firstly demonstrated that ER status influences gemcitabine efficacy via modulating the autophagy in breast cancer cells.

Steroids from the rhizome of Anemarrhena asphodeloides and their cytotoxic activities

Cancer remains a major killer worldwide. To search for novel naturally occurring compounds that are cytotoxic to cancer cells to be used as lead structures for drug development, five new steroids (1–5) along with seven known ones (6–12) were isolated from the rhizome of Anemarrhena asphodeloides Bge. Their structures were established by detailed spectral studies, including 1D-NMR, 2D-NMR, HR-ESI-MS and by comparison with literature data. These compounds exhibited different levels of growth inhibition against A549, HepG2, Hep3B, Bcap37 and MCF7 cell lines in vitro. Compounds 9, 10 and 11 showed potent inhibitory against all the tested cell lines with IC50 values ranging from 0.35±0.15 to 25.53±0.31μM. The three compounds displayed stronger inhibitory activities against A549, HepG2 and Hep3B cell lines compared with the positive control 5-fluorouracil. The experimental data obtained permit us to identify the roles of the sugar moieties, hydroxyl group, double bond and F-ring with regard to their cytotoxic activities.

Induction of Solasonine on Apoptosis of Human Breast Cancer Bcap-37 Cells through Mitochondria-Mediated Pathway

ObjectiveTo study the in vitro antiproliferative effect and probable mechanism of solasonine on human breast cancer Bcap-37 cells, meanwhile, make comparison with solamargine. MethodsThe cytotoxicity was evaluated by MTT assay. The cell damage and type of cell death were examined through Hoechst33342/PI and Annexin V/PI staining, respectively. Mitochondrial membrane potential was detected by JC-1 staining. The expression of Bcl-2, Bcl-xL, Bax, and cytochrome c was determined by immunoblot method, and the activation of caspase-3 was analyzed by immunocytochemistry method. ResultsSolasonine showed the different extents of cytotoxicity on eight human tumor cell lines as well as four human normal cell lines, and the IC50 values of solasonine ranged from 12.73 to 37.15 μmol/L. Cell apoptosis and mitochondria depolarization were observed in Bcap-37 cells after treatment with solasonine for 24 h, respectively. In immunoblot and immunocytochemistry analysis, solasonine obviously induced the up-regulation of Bax and down-regulation of Bcl-2 and Bcl-xL, caused the release of cytochrome c from mitochondria into cytosol, and increased the expression of both pro- and cleaved caspase-3. Solamargine exhibited stronger antipoliferative activity than solasonine, but the similar mechanism in Bcap-37 cells in this study. ConclusionSolasonine possesses the antiproliferative effect on tumor cells. Regulation of the levels of Bcl-2, Bcl-xL, Bax, and activation of mitochondria cytochrome c-dependent apoptosis pathway might be one of its main antitumor mechanisms against breast cancer cells. In view of the cytotoxic effect of solasonine and solamargine also shown on normal cells, the safety needs concern when the antitumor activity is studied.

Distinct characterization of two vinorelbine-resistant breast cancer cell lines developed by different strategies.

Resistance to chemotherapy is a major obstacle to the successful treatment of breast cancer patients. Recently, we successfully established two vinorelbine-resistant sublines, BC-DS and BC-TS, from the human breast cancer cell line BCap37, with different 'two-stage screening methods'. Interestingly, though BC-DS and BC-TS were developed from the same BCap37 cell line with the same drug, they showed remarkable differences. Compared with the parental BCap37 cells both BC-DS and BC-TS had resistance to vinorelbine, but the resistant characterizations are both unstable. BC-DS showed increased migration capability while BC-TS showed reduced migration capability. When investigating their multidrug resistance, we found BC-DS became more sensitive to methotrexate, which suggested that combination of MTX and vinorelbine could be a new treatment strategy. Moreover, BC-DS and BC-TS overexpressed P-glycoprotein at different levels. Our research also showed that the present clinical usage of vinorelbine is reasonable. These findings suggest that the vinorelbine-induced multiple drug resistance (MDR) sublines may be used as an in vitro model not only to further elucidate possible mechanisms of MDR involved in the human breast cancer, but also to find methods to optimize the curative effect of vinorelbine in clinic.

Cryptotanshinone inhibits proliferation and induces apoptosis via mitochondria-derived reactive oxygen species involving FOXO1 in estrogen receptor-negative breast cancer Bcap37 cells

Cryptotanshinone inhibits proliferation and induces apoptosis of the estrogen receptor-negative breast cancer Bcap37 cells via FOXO1 inhibition and ROS-mediated PI3K/AKT/mTOR signaling pathways.

Easy synthesis of highly fluorescent carbon dots from albumin and their photoluminescent mechanism and biological imaging applications

A simple and green approach was developed to synthesize highly fluorescent carbon dots (CDs) using albumin as a carbon source in aqueous solution at room temperature. The CDs were characterized by excellent monodispersion, superior photostability, pH-independent emission, long fluorescence lifetime and high quantum yield (QY). The photoluminescent (PL) mechanism of CDs was explored by means of time-resolved PL decay, and the results revealed that PL originated from the emission of both defect state and intrinsic state. In addition, biological imaging with the application of CDs was carried out in human breast cancer Bcap-37 cell, which demonstrated that CDs were provided with an excellent biocompatiblity, low cytotoxicity and good transmembrane ability. Besides, CDs could be considered as a potential substitute for organic dyes or semiconductor quantum dots (SQDs) in biological imaging.

Emodin induces apoptosis of human breast cancer cells by modulating the expression of apoptosis-related genes.

The aim of this study was to investigate the effects of emodin on the proliferation of human breast cancer cells Bcap-37 and ZR-75-30. Cell viability following emodin treatment was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The effects of emodin on apoptosis were determined by flow cytometry using Annexin V-fluorescein isothiocyanate and propidium iodide staining. Quantitative polymerase chain reaction and western blot analysis were used to determine changes in the expression of apoptotic genes and protein, respectively. The effect of emodin on the invasiveness of breast cancer cells was evaluated by Matrigel invasion assay. Treatment of breast cancer cells Bcap-37 and ZR-75-30 with emodin was observed to inhibit the growth and induced apoptosis in a time- and dose-dependent manner. Emodin reduced the level of Bcl-2 and increased levels of cleaved caspase-3, PARP, p53 and Bax. These findings indicate that emodin induces growth inhibition and apoptosis in human breast cancer cells. Emodin may be a potential therapeutic agent for the treatment of breast cancer.

Synthesis and in vitro antitumor evaluation of betulin acid ester derivatives as novel apoptosis inducers

Nineteen betulin derivatives modified at the C-3 and C-28 positions were synthesized and assessed for antitumor activities against the MGC-803, PC3, Bcap-37, A375, and MCF-7 human cancer cell lines in vitro by MTT assay. Some derivatives (compounds 3a–3d and 5) displayed strong antitumor properties, with IC50 values between 4 and 18 μM. Compound 3c, containing piperidine group at C-28 position, had IC50 values of 4.3, 4.5, 5.2, 7.5, and 5.2 μM on the five cancer cell lines, respectively. Subsequent fluorescence staining and flow cytometric analysis indicated that compound 3c induced apoptosis in MGC-803 cell line, with an apoptosis ratio of 31.11% after 36 h of treatment at 10 μM 3c.

Synthesis and biological evaluation of betulonic acid derivatives as antitumor agents

Structural modification was performed at the C-28 position of betulonic acid (BetA). Twenty-five BetA derivatives were synthesized, and evaluated for their antitumor activities against MGC-803, PC3, Bcap-37, A375, and MCF-7 human cancer cell lines by MTT assay. Among the derivatives, most of the derivatives had significant antiproliferative ability (IC50 < 19 μM). Compound 3k, the most active compound, showed IC50 values of 3.6, 5.6, 4.2, 7.8, and 5.2 μM on the five cancer cell lines respectively, and was selected to investigate cell apoptosis by subsequent florescence staining and flow cytometry analysis. The results revealed that compound 3k could induce apoptosis in MGC-803 cell lines, and the apoptosis ratios reached 28.33% after 36 h of treatment at 10 μM. In addition, the study of cancer cell apoptotic signaling pathway indicated that the apoptosis of MGC-803 cells induced by compound 3k could be through the mitochondrial intrinsic pathway.

Codelivery of paclitaxel and small interfering RNA by octadecyl quaternized carboxymethyl chitosan-modified cationic liposome for combined cancer therapy.

Conventional therapeutic approaches for cancer are limited by cancer cell resistance, which has impeded their clinical applications. The main goal of this work was to investigate the combined antitumor effect of paclitaxel with small interfering RNA modified by cationic liposome formed from modified octadecyl quaternized carboxymethyl chitosan. The cationic liposome was composed of 3β-[N-(N', N'-dimethylaminoethane)-carbamoyl]-cholesterol, dioleoylphosphatidylethanolamine, and octadecyl quaternized carboxymethyl chitosan. The cationic liposome properties were characterized by Fourier transform infrared spectroscopy, dynamic light scattering and zeta potential measurements, transmission electron microscopy, atomic force microscopy, and gel retardation assay. The cationic liposome exhibited good properties, such as a small particle size, a narrow particle size distribution, a good spherical shape, a smooth surface, and a good binding ability with small interfering RNA. Most importantly, when combined with paclitaxel and small interfering RNA, the composite cationic liposome induced a great enhancement in the antitumor activity, which showed a significantly higher in vitro cytotoxicity in Bcap-37 cells than liposomal paclitaxel or small interfering RNA alone. In conclusion, the results indicate that cationic liposome could be further developed as a codelivery system for chemotherapy drugs and therapeutic small interfering RNAs.

An improved Tet-on system to tightly conditionally regulate reporter gene expression

Reporter genes are often used as markers to track the integration and expression of target genes in animal genetic engineering. To avoid potential side effects from reporter genes, in this study an improved Tet-on system was developed to control reporter gene expression, and its effectiveness was explored in transgenic cells. First, the rtTA protein was fused with Tat and NLS proteins to obtain the prokaryotic expression vector pET32a-Tat-rtTA-NSL. A eukaryotic transgenic vector was constructed, p-HS4-BPA-TmA-HS4, in which the reporter (mCherry) and target (PRL) genes were promoted by TRE and BCN, respectively. After confirming the functionality of the transgenic vector, purified rtTA protein and Dox were added to induce expression of the mCherry gene. The optimal amount of purified rtTA protein, its influence on target gene expression, and the time of rtTA protein action were each investigated separately. The results showed that rtTA protein was expressed in transformed E. coli with IPTG induction. TRE could promote mCherry gene expression by co-transfecting the constructed transgenic vector and prtTA plasmid. When purified rtTA protein and Dox were added, red fluorescence was observed in Bcap-37 cells transfected with the p-HS4-BPA-TmA-HS4 vector, and the exogenous PRL gene was expressed regardless of mCherry gene expression. The optimal amount of rtTA protein was 16 μg/mL, and it needed about 6 h to promote mCherry gene expression in transfected cells. These results demonstrate that the expression of the mCherry reporter gene can be tightly and conditionally regulated by our Tet-on system.