Breast Cancer Bcap-37 Cells Research Articles

Green synthesis of fluorescent carbon dots from ascorbic acid and their application in sensing and biological imaging

A simple, highly efficient, and environmentally friendly one-step method has been developed to synthesize fluorescent carbon dots (CDs) with the assistance of hydrogen peroxide (H2O2). Here H2O2 acts as a green accelerator to promote the preparation of CDs, while temperature plays a critical role in controlling the entire synthesis process. The prepared CDs demonstrate monodispersion, with an average diameter of ∼6.8 nm, superior stability, and excitation-dependent photoluminescent (PL) behavior. The PL mechanism of the CDs was investigated using time-resolved PL decay, revealing that the PL originates from both the defect state and the intrinsic state of the CDs. Furthermore, the CDs show significant promise as pH sensors and versatile nanothermometry devices, owing to their remarkable sensitivity to both pH and temperature, as demonstrated by the pronounced dependence of their steady-state fluorescence emission spectra. It’s worth noting that temperature and pH sensors present significant reversibility, sensitivity, and linearity. More importantly, the CDs display low cytotoxicity, good biocompatibility, and the ability to enter human breast cancer Bcap-37 cells, making them highly suitable candidates for cellular imaging and labeling.

Peptide specifically binding to human medullary breast carcinoma Bcap-37 cells selected by phage display in vivo and its property as well as combination effect

Objective To investigate the property and the combination effect of the peptide specifically binding to human medullary breast cancer Bcap-37 cells by using phage display in vivo and to provide molecular targeting probe for early diagnosis of breast cancer. Methods The human medullary breast carcinoma Bcap-37 cells tumor-bearing nude mice model was prepared and three rounds in vivo were performed by using Ph.D.-C7CTM phage display peptide library. The distribution of screened phages in tumors and normal tissues was detected by using immunohistochemistry. The affinity of monoclonal phage to Bcap-37 cells was identified by using enzyme linked immunosorbent assay (ELISA). The positive monoclonal phage DNA was taken and sequenced, and the sequence with high repetition rate was selected to synthesize peptide by using chemical methods. Optical molecular probe was prepared and fluorescence molecular imaging was used to test its specificity and targeting ability for breast transplantation tumor of tumor-bearing nude mice in vivo. Results The recovery rate of phage in the third round screening in vivo was 107.2 times than that in the first round. Immunohistochemical results showed that the phages binding to the tumor tissues were increased successively with the increasing screening rounds in vivo. The number of phages binding to tumor tissues was more than that binding to normal tissues (lung, skeletal muscle, liver and kidney). The absorbancy (A) value of section scanning image in the tumor tissues was higher than that in the normal tissues, and the difference was statistically significant different (P < 0.05). ELISA results showed that 22 phages (affinity≥2) among the 50 randomly selected monoclonal phage were positive. After DNA sequencing analysis of the positive monoclonal phage, 4 repeat amino acid sequences were obtained. The fluorescein isothiocyanate-labelled (FITC)-CSPLNTRFC with the highest repetition rate was synthesized for FITC-CSPLNTRFC peptide. Bcap-37 cells tumor-bearing nude mice model assay in vivo showed that FITC-CSPLNTRFC peptide could significantly enriched in the breast xenograft tissues. Conclusion CSPLNTRFC peptide specifically binding to human medullary breast cancer Bcap-37 cells can be screened out successfully by using phage display in vivo, which will be helpful to vitro studies on the early diagnosis of breast cancer. Key words: Breast neoplasms; Peptide library; Phage display; Specifically binding peptide

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.

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.

Multisite mutation of monomer survivin with enhanced effect on apoptosis regulation of breast cancer cells

Survivin is an important protein in regulating both cell apoptosis and proliferation. It has attracted growing attentions in recent years as a promising target for cancer therapy. Previous studies have revealed that monomeric survivin regulated apoptosis in a more significant way than the wild-type survivin that generally contains a large portion of its dimers. In order to investigate the roles of monomeric mutant survivin apoptosis and cell cycle regulation of human cancer cells, we developed and tested three dominant-negative mutants with multisite mutations (MSM) including TAT-survivin34/101/102, TAT-survivin34/117/101/102 and TAT-survivin117/101/102. Results revealed that MSM mutants remained as monomers under ambient conditions, and induced cells (breast cancer Bcap-37 cells) apoptosis even more efficiently, primarily through the caspase-dependent and Bcl-2-related pathways, than non-monomeric mutants. We further identified that the TAT-survivin34/101/102 and TAT-survivin117/101/102 MSM significantly inhibited the proliferation of Bcap-37 cells and arrested cells in S and G2/M phases, while TAT-survivin34/117/101/102 arrested cells in G2/M phase. It appeared to us that TAT-survivin34/101/102 and TAT-survivin117/101/102 also inhibited cell proliferation more significantly. These findings suggest that such MSM afford monomeric survivin with promising potentials for cancer therapy.

Effect of Norcantharidin on the Human Breast Cancer Bcap-37 Cells

Norcantharidin (NCTD), a chemically modified form of cantharidin, is a potential anticancer drug. In this study, the effects of NCTD on the cellular viability, reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and DNA damage in the human breast cancer cell line Bcap-37 were investigated with confocal and fluorescence microscopy. The cell cycle was further analyzed using the CellQuest software of a Becton-Dickinson FACS flow cytometer. The results indicated that the cellular viability was decreased with the growing concentrations of NCTD and time exposure. Moreover, the fluorescence intensity of ROS was increased, whereas the MMP was decreased in Bcap-37 cells with the growing concentrations of NCTD. NCTD induced a dose-dependent DNA damage and reduced the G1 peak in Bcap-37 cells. The G2/M peak of Bcap-37 was also decreased by the higher concentration of NCTD.

Estrogen receptor α attenuates therapeutic efficacy of paclitaxel on breast xenograft tumors

Through transfection of ERα into ERα- breast cancer BCap37 cells, we previously established a pair of isogenic ERα-/ERα+ tumor cell lines BC-V/BC-ER, and demonstrated that ERα induces chemoresistance in vitro. The present study is designed to investigate whether this ERα-mediated chemoresistance also occurs in xenograft models. Meanwhile, we would test whether fulvestrant, a clinically-used antiestrogen agent, can reverse ERα-mediated chemoresistance in vivo. Xenograft models were established through transplantation of BC-ER and BC-V cells into nude mice. Mice were then treated with vehicle, paclitaxel, with or without administration of estrogen (E2). The potential influence of E2/ERα on the therapeutic efficacy of paclitaxel was then evaluated. Furthermore, we investigated whether fulvestrant can sensitize ERα+ tumors to paclitaxel in vivo. Compared with the group treated with PTX alone, co-treatment of E2 significantly reduced the therapeutic efficacy of paclitaxel in BC-ER tumors (51.23 vs. 36.71%, p < 0.01). Biochemical studies demonstrated that E2 significantly interfered with paclitaxel's cytotoxicity in BC-ER tumors. Importantly, we found that fulvestrant significantly repressed ERα expression, potentiated paclitaxel-induced apoptosis and sensitized BC-ER tumors to PTX in the presence of E2 (39.12 vs. 53.64%, p < 0.01). In summary, this study demonstrated that E2/ERα attenuates therapeutic efficacy of paclitaxel in an isogenic ERα+ xenograft model. Furthermore, we demonstrated that fulvestrant significantly reversed the ERα-mediated chemoresistance in vivo. These findings may have potential implications on the clinical practice of antiestrogen and chemotherapeutic agents.

Anti-Tumor Activity of a Novel Protein Obtained from Tartary Buckwheat

TBWSP31 is a novel antitumor protein that was isolated from tartary buckwheat water-soluble extracts. The objective of this paper was to investigate the anti-proliferative effects of TBWSP31 on breast cancer Bcap37cells and to explore its possible mechanism. After treatment of Bcap37 cells with TBWSP31, typical apoptotic morphological changes were observed by inverted microscopy and scanning electron microscopy (SEM), such as detachment from the culture plate, change to a round shape, cell shrinkage, the absence of obvious microvilli, plasma membrane blebbing, and formation of apoptotic bodies. Cell-cycle analysis revealed that treatment with TBWSP31 resulted in a G0/G1 arrest and prevented the cells from growing from G0/G1 phase to S phase, which was most prominent at 48 h. The expression of bcl-2 and Fas were detected quantitatively by FCM, which showed that TBWSP31 induced-apoptosis may be involved with the participation of Fas and bcl-2. These results suggest that TBWSP31 is a potential antitumor compound and that apoptosis induced by TBWSP31 is a key antitumor mechanism.

Fulvestrant (ICI 182,780) sensitizes breast cancer cells expressing estrogen receptor α to vinblastine and vinorelbine

Cumulative data suggest that some chemotherapeutic agents may be less effective in estrogen receptor alpha positive (ER+) breast tumors than ER negative (ER-) tumors, which has raised a clinically relevant question as to how to reverse this ER-mediated chemoresistance in ER+ breast tumors. This study is to investigate the possible influence of estrogen receptor alpha (ERalpha) on the therapeutic effects of vinblastine and vinorelbine on breast cancer cells and explore whether combination of anti-estrogen agent fulvestrant (ICI 182, 780) may enhance the sensitivity of ERalpha+ cells to these chemotherapeutic agents. Through comparing ER+ with ER- human breast tumor cells or through stable transfection of an ERalpha expression vector into ER negative human breast cancer BCap37 cells, a series of assays were applied to determine the sensitivity of ER+ and ER- breast tumor cells to vinblastine and vinorelbine in the presence or absence of 17-beta-estradiol and/or fulvestrant. 17-beta-Estradiol showed no effect on the sensitivity of ER- MDA-MB-468 and BCap37 cells to the treatment of vincristine or vinblastine, but it significantly reduced the sensitivity of ER+ T47D cells and BCap37 cells expressing ERalpha to the two drugs mentioned. Further analyses show that ERalpha has little effect on vinca alkaloids-induced mitotic arrest, but dramatically affects their ability to induce tumor cell apoptosis. Moreover, through a series of assays, we also demonstrated that the combination of fulvestrant, a selective ER down-regulator, could reverse the resistance of ER+ breast tumor cells to vinca alkaloids and even produce synergistic effects. The findings obtained from this study have provided important evidence that expression and subsequent activation of ERalpha are associated with resistance of breast cancer cells to vinca alkaloids. This study also suggested that the combination of anti-estrogen agents, such as fulvestrant, might be a novel strategy to reverse ER-mediated chemoresistance or sensitize ER+ breast tumors to vinca alkaloids and possibly other chemotherapeutic agents.

Effects of emodin on the gene expression profiling of human breast carcinoma cells

Background: The mechanism of emodin-mediated cell apoptosis has been investigated extensively in many types of human cancer cells. Our previous study demonstrated that emodin induced apoptosis through the decrease of Bcl-2/Bax ratio and the increase of cytoplasm cytochrome c concentration in human breast cancer BCap-37 cells. However, emodin's reaction to breast cancer cells remains elusive. Materials and methods: An apoptosis-associated cDNA microarray comprised of 458 known genes, namely, death receptors, calpains, death kinases, granzymes, DNA fragmentation proteins, caspases and Bcl-2 family, was used to determine the impact of emodin in breast cancer BCap-37 cells. Furthermore, the candidate emodin target genes were further evaluated via real-time quantitative PCR and Western blot analysis. Results: We found that gene expression profiling in human breast cancer BCap-37 cells was altered when exposed to emodin. Thirty of the unique genes that were either induced or repressed in response to emodin-induced apoptosis were also identified. A follow-up study characterized p53, emodin-induced gene, IGF-2, and emodin-repressed gene, and the downstream proteins were also seen as possible molecular targets of emodin. Conclusion: Data from this study provide novel evidence that emodin induces gene expression profiling changes, but has no effects on caspases. In addition, the p53 pathway may cooperate with the IGF-2 pathway, resulting in an emodin-induced apoptosis through disruption of the mitochondrial signaling pathway in BCap-37 cells.

Emodin-induced apoptosis in human breast cancer BCap-37 cells through the mitochondrial signaling pathway

Emodin, a natural anthraquinone compound isolated from the rhizome of rhubarb, is reported to suppress the growth of tumor in many clinical situations. In this study, we focused on the effect of emodin in human breast cancer BCap-37 cells and further understand the underlying molecular mechanism in treating breast cancer. Using MTT assay and flow cytometry, we demonstrated the critical role of emodin in the suppression of the proliferation of BCap-37 cells based on a concentration-and time-dependent manner. The increase of apoptotic rate was also observed after incubation of BCap-37 cells on emodin at 20 microM and 50 microM for 48 h. The cells exhibited typical apoptotic features including cellular morphological change, chromatin condensation and membrane blebbing. The results of the study further showed that Bcl-2 level decreased, while Bax and cytosolic cytochrome c levels in sample cells increased after the emodin treatment by using Western blot. The decline in the Bcl-2/Bax ratio and the increase of cytosolic cytochrome c concentration were consistent with the increase of the apoptotic ratio. The results strongly suggest that the disruption of the mitochondrial signaling pathway was involved in emodin-induced apoptosis in BCap-37 cells.

Estrogen Receptor α Mediates Breast Cancer Cell Resistance to Paclitaxel through Inhibition of Apoptotic Cell Death

Estrogen receptors (ER) are expressed in approximately 65% of human breast cancer. Cumulative data from clinical trials and retrospective analyses suggest that some chemotherapeutic agents may be less effective in patients with ER-positive (ER+) tumors than those with ER-negative (ER-) tumors. Paclitaxel is an active agent used in breast cancer chemotherapy. To investigate the possible influence of ER on the therapeutic efficacy of paclitaxel and its underlying mechanism, we established several isogenic ER+ cell lines by stable transfection of ERalpha expression vectors into ER- breast cancer BCap37 cells. We showed that 17-beta estradiol significantly reduces the overall cytotoxicity of paclitaxel in BCap37-expressing ERalpha but has no influence on the ER- parental cells. Further analyses indicate that expression of ERalpha in BCap37 cells mainly interferes with paclitaxel-induced apoptotic cell death, without affecting paclitaxel-induced microtubule bundling and mitotic arrest. Moreover, we found that the addition of ICI 182,780 (Fulvestrant), a selective ER down-regulator, could completely reverse the resistance of ER+ BCap37 cells to paclitaxel. These findings showed that ERalpha-mediated breast tumor cell resistance to paclitaxel was through selective inhibition of paclitaxel-induced tumor cell apoptosis. Additionally, the combination of ICI 182,780 also sensitizes MCF-7 and T47D cell lines to the treatment of paclitaxel, which further confirmed the correlation between ERalpha and drug resistance in ER+ tumor cells. The results obtained from this study provide useful information for understanding ER-mediated resistance to paclitaxel and possibly other antineoplastic agents.

Regulation of Vinca alkaloid-induced apoptosis by NF-κB/IκB pathway in human tumor cells

Abstract Antimicrotubule Vinca alkaloids, such as vinblastine and vincristine, interfere with the dynamics of microtubules and have shown significant cell killing activity in a variety of tumor cells through induction of apoptosis. The mechanism by which Vinca alkaloids induce apoptosis is not entirely clear. In this study, we found that glucocorticoids inhibit Vinca alkaloid-induced apoptosis without affecting G2-M arrest in human breast cancer BCap37 cells and human epidermoid tumor KB cells, suggesting that Vinca alkaloid-induced apoptosis may occur via a pathway independent of cell cycle arrest. Further analyses indicated that Vinca alkaloids cause significant degradation of IκBα, which in turn results in nuclear factor-κB (NF-κB) activation. Transfection of antisense IκBα in BCap37 cells sensitizes Vinca alkaloid-induced apoptosis. Moreover, in vitro kinase assays show that the activity of IκB kinase (IKK) was activated by Vinca alkaloids and was not affected by glucocorticoids. Stable transfection of dominant-negative deletional mutant IκBα, which is insensitive to IKK-mediated phosphorylation and degradation, resulted in the inhibition of Vinca alkaloid-induced NF-κB activation and reduced sensitivity of tumor cells to Vinca alkaloid-induced apoptosis. These findings suggest that the NF-κB/IκB signaling pathway may contribute to the mediation of Vinca alkaloid-induced apoptosis in human tumor cells.