Pathway In MCF-7 Cells Research Articles

Enantioselective Effects of Metalaxyl Enantiomers on Breast Cancer Cells Metabolic Profiling Using HPLC-QTOF-Based Metabolomics.

In this study, an integrative high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF) based metabolomics approach was performed to evaluate the enantioselective metabolic perturbations in MCF-7 cells after treatment with R-metalaxyl and S-metalaxyl, respectively. Untargeted metabolomics profile, multivariate pattern recognition, metabolites identification, and pathway analysis were determined after metalaxyl enantiomer exposure. Principal component analysis (PCA) and partitial least-squares discriminant analysis (PLS-DA) directly reflected the enantioselective metabolic perturbations induced by metalaxyl enantiomers. On the basis of multivariate statistical results, a total of 49 metabolites including carbohydrates, amino acids, nucleotides, fatty acids, organic acids, phospholipids, indoles, derivatives, etc. were found to be the most significantly changed metabolites and metabolic fluctuations caused by the same concentration of R-metalaxyl and S-metalaxyl were enantioselective. Pathway analysis indicated that R-metalaxyl and S-metalaxyl mainly affected the 7 and 10 pathways in MCF-7 cells, respectively, implying the perturbed pathways induced by metalaxyl enantiomers were also enantioselective. Furthermore, the significantly perturbed metabolic pathways were highly related to energy metabolism, amino acid metabolism, lipid metabolism, and antioxidant defense. Such results provide more specific insights into the enantioselective metabolic effects of chiral pesticides in breast cancer progression, reveal the underlying mechanisms, and provide available data for the health risk assessments of chiral environmental pollutants at the molecular level.

Inhibition of the MAPK pathway alone is insufficient to account for all of the cytotoxic effects of naringenin in MCF-7 breast cancer cells

Estrogen receptor (ER) antagonists such as tamoxifen (Tam) have been used successfully to treat ER+ breast cancers for more than 30 years. Unfortunately, long term use of Tam can result in resistance. Tam resistance is associated with the activation of growth factor signaling pathways that promote cell proliferation and survival. The mitogen-activated protein kinase (MAPK), is up-regulated in Tam resistant (Tam-R) cells. Previous studies have reported that the flavanone, naringenin (Nar) can inhibit cell proliferation and induce apoptosis in ER+ breast cancer cells. Furthermore, Nar has been shown to inhibit the MAPK signaling pathways in MCF-7 cells. In this report we investigated whether inhibition of MAPK alone is mediating the effects of Nar on cell proliferation and viability. These studies will determine the mechanism of action of Nar. Tam-R MCF-7 breast cancer cells were treated with Nar or U0126, a MAPK kinase inhibitor. Our studies show that while both U0126 and Nar impaired cell proliferation and viability the combination of U0126 and Nar resulted in greater inhibition of cell viability than either compound alone. It has been previously reported that Nar can bind the ER. Our lab has also shown that Nar localizes ERα to a peri-nuclear region of the cell. Confocal microscopy revealed that in U0126 treated cells ERα displayed an even distribution across the cytoplasm as seen in untreated Tam-R cells. These studies suggest that MAPK is not the only target of Nar.

DHA blocks TPA-induced cell invasion by inhibiting MMP-9 expression via suppression of the PPAR-γ/NF-κB pathway in MCF-7 cells

Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is considered to have applications in cancer prevention and treatment. The beneficial effects of DHA against cancer metastasis are well established; however, the mechanisms underlying these effects in breast cancer are not clear. Cell invasion is critical for neoplastic metastasis, and involves the degradation of the extracellular matrix by matrix metalloproteinase (MMP)-9. The present study investigated the inhibitory effect of DHA on MMP-9 expression and cell invasion induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in the MCF-7 breast cancer cell line. DHA inhibited the TPA-induced activation of mitogen-activated protein kinase (MAPK) and the transcription of nuclear factor (NF)-κB, but did not inhibit the transcription of activator protein-1. DHA increased the activity of peroxisome proliferator-activated receptor (PPAR)-γ, an effect that was reversed by the application of the PPAR-γ antagonist GW9662. In addition, combined treatment with GW9662 and DHA increased NF-κB-related protein expression. These results indicate that DHA regulates MMP-9 expression and cell invasion via modulation of the MAPK signaling pathway and PPAR-γ/NF-κB activity. This suggests that DHA could be a potential therapeutic agent for the prevention of breast cancer metastasis.

Triolein from Coix Lacryma-Jobi Induces Cell Cycle Arrest through P53/P21Signaling Pathway

p53, a tumor suppressor protein, has important roles in DNA repair, cell cycle and apoptosis, is a one of the key events in cancer development. Coix lacryma-jobi seed has been used as a food and traditional medicine plant with anti-oxidant, anti-cancer and anti-diabetic effects. In currently research, we identified the most potent p53-increasing compound among 4 compounds (1-4) found in Coix lacryma-jobi and demonstrated its molecular mechanism in MCF-7 cells. Among the four isolated compounds (1-4), triolein most increased p53. Triolein treatment induced p53, p21, p27 and Bax in MCF-7 cells. Moreover, triolein caused S phase arrest through suppression of CDK1, phopho-Rb and E2F1 in dose-dependent manner. We also observed the decreasing of DNA synthesis by triolein. These data suggest that triolein may induced cell cycle restart involve DNA synthesis and apoptosis pathway in MCF-7 cells. (Less)

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.

Design, synthesis and evaluation of 6-aryl-indenoisoquinolone derivatives dual targeting ERα and VEGFR-2 as anti-breast cancer agents

The estrogen receptors have played important roles in breast cancer development and progression. Selective estrogen receptor modulators, such as Tamoxifen, have showed great benefits in the treatment and prevention of breast cancer. But the disadvantages of induction of endometrial cancer and drug resistance have limited their use. Multiple ligand which act at multiple biomolecular targets may exert favorable advantages of improved efficacy with lower incidence of side effects. In this work, we described the synthesis and evaluation of a series of 6-aryl-indenoisoquinolone derivatives as dual ERα and VEGFR-2 inhibitors. These compounds presented good ERα binding affinity and ERα antagonistic activity, as well as potent VEGFR-2 inhibitory potency. They also possessed excellent anti-proliferative activities against MCF-7, MDA-MB-231, Ishikawa and HUVEC cell lines. Further investigation of selective compound 21c showed that it was able to inhibit the activation of VEGFR-2 and the signaling transduction of Raf-1/MAPK/ERK pathway in MCF-7 cells.

Overexpression of SDF-1 activates the NF-κB pathway to induce epithelial to mesenchymal transition and cancer stem cell-like phenotypes of breast cancer cells

The formation of EMT and EMT-induced CSC-like phenotype is crucial for the metastasis of tumor cells. The stromal cell-derived factor-1 (SDF-1) is upregulated in various human carcinomas, which is closely associated with proliferation, migration, invasion and prognosis of malignancies. However, limited attention has been directed towards the effect of SDF-1 on epithelial to mesenchymal transition (EMT) or cancer stem cell (CSC)-like phenotype formation in breast cancer cells and the related mechanism. In the present study, we screened MCF-7 cells with low SDF-1 expression level for the purpose of evaluating whether SDF-1 is involved in EMT and CSC-like phenotype formation in MCF-7 cells. The pEGFP-N1-SDF-1 plasmid was transfected into MCF-7 cells, and the stably overexpressed SDF-1 in MCF-7 cells was confirmed by real-time PCR and western blot analysis. Colony formation assay, MTT, wound healing assay and Transwell invasion assay demonstrated that overexpression of SDF-1 significantly boosted the proliferation, migration and invasion of MCF-7 cells compared with parental (P<0.05). Flow cytometry analysis revealed a notable increase of CD44+/CD24- subpopulation in SDF-1 overexpressing MCF-7 cells (P<0.001), accompanied by the apparently elevated ALDH activity and the upregulation of the stem cell markers OCT-4, Nanog, and SOX2 compared with parental (P<0.01). Besides, western blot analysis and immunofluorescence assay observed the significant decreased expression of E-cadherin and enhanced expression of slug, fibronectin and vimentin in SDF-1 overexpressed MCF-7 cells in comparison with parental (P<0.01). Further study found that overexpression of SDF-1 induced the activation of NF-κB pathway in MCF-7 cells. Conversely, suppressing or silencing p65 expression by antagonist or RNA interference could remarkably increase the expression of E-cadherin in SDF-1 overexpressed MCF-7 cells (P<0.001). Overall, the above results indicated that overexpression of SDF-1 enhanced EMT by activating the NF-κB pathway of MCF-7 cells and further induced the formation of CSC-like phenotypes, ultimately promoting the proliferation and metastasis of MCF-7 cells. Therefore, SDF-1 may further be assessed as a potential target for gene therapy of breast cancer.

ERβ up-regulation was involved in silibinin-induced growth inhibition of human breast cancer MCF-7 cells

We previously reported that silibinin induced a loss of cell viability in breast cancer (MCF-7) cells by ERα down-regulation. But whether this cytotoxicity depends on another estrogen receptor, ERβ, has yet to be elucidated. Therefore, we sought to explore the effects of ERβ modulation on cell viability by using an ERβ-selective agonist (Diarylprepionitrile, DPN) and an antagonist (PHTPP). Our data demonstrated that ERβ served as a growth suppressor in MCF-7 cells, and the incubation of silibinin, elevated ERβ expression, resulting in the tumor growth inhibition. The cytotoxic effect of silibinin was diminished by PHTPP and enhanced by DPN. Silencing of ERβ by siRNA confirmed these results. Apoptotic cascades, including the sequential activation of caspase-9 and -6, and finally the cleavage of caspase substrates, PARP and ICAD, caused by treatment with silibinin, were all repressed by PHTPP pre-treatment but exacerbated by DPN. Unlike ERα, ERβ did not involve autophagic process in the regulation, since neither autophagic inhibitor (3-MA) nor the inducer (rapamycin) affected the cell survival rates regardless ERβ activity. Taken together, silibinin induced apoptosis through mitochondrial pathway by up-regulating ERβ pathways in MCF-7 cells without the involvement of autophagy.

Suppression of TPA-induced cancer cell invasion by Peucedanum japonicum Thunb. extract through the inhibition of PKCα/NF-κB-dependent MMP-9 expression in MCF-7 cells.

Metastatic cancers spread from their site of origin (the primary site) to other parts of the body. Matrix metalloproteinase-9 (MMP-9), which degrades the extracellular matrix, is important in metastatic cancers as it plays a major role in cancer cell invasion. The present study examined the inhibitory effect of an ethanol extract of Peucedanum japonicum Thunb. (PJT) on MMP-9 expression and the invasion of MCF-7 breast cancer cells induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Western blot analysis, gelatin zymography, and reverse transcription-quantitative PCR revealed that PJT significantly suppressed MMP-9 expression and activation in a dose-dependent manner. Furthermore, PJT attenuated TPA-induced nuclear translocation and the transcriptional activation of nuclear factor (NF)-κB. The results indicated that the PJT-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involved the suppression of the PKCα/NF-κB pathway in MCF-7 cells. Thus, the inhibition of MMP-9 expression by PJT may have potential value as a therapy for restricting the invasiveness of breast cancer.

Wogonoside inhibits angiogenesis in breast cancer via suppressing Wnt/β-catenin pathway.

Wogonoside, a main flavonoid component derived from the root of Scutellaria baicalensis Georgi, has been reported to have anti-angiogenesis and anti-leukemia activities. However, whether it can inhibit tumor angiogenesis is unclear. In this study, we investigate the inhibitory effect of wogonoside on angiogenesis in breast cancer and its underlying mechanisms. ELISA assay shows that wogonoside (25, 50, and 100 µM) decreases the secretion of VEGF in MCF-7 cells by 30.0%, 35.4%, and 40.1%, respectively. We find it inhibits angiogenesis induced by the conditioned media from MCF-7 cells in vitro and in vivo by migration, tube formation, rat aortic ring, and chicken chorioallantoic membrane (CAM) assay. Meanwhile, wogonoside can inhibit the growth and angiogenesis of MCF-7 cells xenografts in nude mice. The reduction of tumor weight can be found both in wogonoside (80 mg/kg) and bevacizumab (20 mg/kg) treated group, and the tumor inhibition rate is 42.1% and 48.7%, respectively. In addition, mechanistic studies demonstrate that wogonoside suppresses the activation of Wnt/β-catenin pathway in MCF-7 cells. Wogonoside (100 µM) decreases the intracellular level of Wnt3a, increases the expression of GSK-3β, AXIN, and promotes the phosphorylation of β-catenin for proteasome degradation significantly. Furthermore, the nuclear accumulation of β-catenin and the DNA-binding activity of β-catenin/TCF/Lef complex are inhibited by 49.2% and 28.7%, respectively, when treated with 100 µM wogonoside. Taken together, our findings demonstrate that wogonoside is a potential inhibitor of tumor angiogenesis and can be developed as a therapeutic agent for breast cancer. © 2015 Wiley Periodicals, Inc.

Abstract 2319: Sulforadex targets breast cancer stem-like cells in patient-derived cells and xenograft tumors

Abstract Sulforadex (SFX) is a novel therapeutic comprising synthetic sulforaphane (SFN) stabilised within α-cyclodextrin. SFN has been studied as an anti-cancer compound for many years however its development has hitherto been hampered due to its inherent instability. Breast cancer stem-like cells (CSCs) have been identified in all molecular subtypes and are believed to be the drivers of breast cancer metastasis. We investigated SFX effects on breast CSC activity using mammosphere formation and aldehyde dehydrogenase (ALDH) activity in patient samples and patient-derived xenograft (PDX) tumours. Mammosphere formation efficiency (MFE) assessed in cells from primary (n = 12) and metastatic (n = 15) samples treated with SFX (5 μM) or vehicle control (water) showed a significant reduction in breast CSC activity following SFX treatment. A reduction greater than 50% in the MFE was observed in both primary (0.52%±0.06 vs 0.19±0.02, p&amp;lt;0.001) and metastatic (0.93%±0.07 vs 0.43±0.04, p&amp;lt;0.001) cells treated with SFX. Importantly, SFX also inhibits breast CSC activity of early (HBCx34) and metastatic (BB3RC31) patient-derived xenograft (PDX) tumours. Using a 14 day in vivo ‘window’ treatment, we observe that SFX (300mg/Kg/day) decreases ALDH+ cells using ALDEFLUOR assay (HBCx34 6.3%±0.4 vs 3%±0.6, p&amp;lt;0.01; BB3RC31 3%±0.6 vs 1±0.2, p&amp;lt;0.05) and MFE (HBCx34 0.64%±0.09 vs 0.35%±0.03, p&amp;lt;0.01; BB3RC31 0.89%±0.06 vs 0.78±0.04). The majority of breast cancers express the estrogen receptor (ER) but these hormone-responsive breast cancers frequently develop resistance to hormonal therapies (e.g. tamoxifen). We have established that CSCs in ER+ BC lack ER expression, representing a potential mechanism of therapeutic resistance. However, SFX targets such surviving CSCs identified by ALDH positivity and mammosphere-initiating capacity following tamoxifen treatment in vivo in ER+ PDX tumours. Combinatorial treatment of tamoxifen (10 mg/kg/day) and SFX (300mg/Kg/day) in a 14 day ‘window’ treatment reduced ALDH+ cells (HBCx34 10%±0.4 vs 4.2%±0.4, p&amp;lt;0.01; BB3RC31 11.3%±1.1 vs 6.9±0.6, p&amp;lt;0.05) and MFE (HBCx34 0.81%±0.07 vs 0.34%±0.02, p&amp;lt;0.01; BB3RC31 0.47%±0.06 vs 0.27±0.04, p&amp;lt;0.05) compared to tamoxifen treatment alone. Mechanistically SFX potently inhibited the canonical Wnt pathway in MCF-7 cells and their endocrine-resistant derivatives and future studies will explore SFX activity on other CSC regulatory pathways. Our data demonstrate that SFX might produce clinically meaningful improvements to endocrine therapy in ER+ BC by reversing CSC mediated resistance. Clinical trials of endocrine therapy in combination with SFX are currently being planned. Citation Format: Bruno M. Simões, Denis Alferez, Rachel Eyre, Kath Spence, Angélica Santiago-Gomez, Iris Tanaka, Bertram Kohler, David Howat, Sacha J. Howell, Robert B. Clarke. Sulforadex targets breast cancer stem-like cells in patient-derived cells and xenograft tumors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2319. doi:10.1158/1538-7445.AM2015-2319

A Bacterial Metabolite, Compound K, Induces Programmed Necrosis in MCF-7 Cells via GSK3β.

Ginsenosides, the major active component of ginseng, are traditionally used to treat various diseases, including cancer, inflammation, and obesity. Among these, compound K (CK), an intestinal bacterial metabolite of the ginsenosides Rb1, Rb2, and Rc from Bacteroides JY-6, is reported to inhibit cancer cell growth by inducing cell-cycle arrest or cell death, including apoptosis and necrosis. However, the precise effect of CK on breast cancer cells remains unclear. MCF-7 cells were treated with CK (0-70 micrometer) for 24 or 48 h. Cell proliferation and death were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assays, respectively. Changes in downstream signaling molecules involved in cell death, including glycogen synthase kinase 3β (GSK3β), GSK3β, β-catenin, and cyclin D1, were analyzed by western blot assay. To block GSK3β signaling, MCF-7 cells were pretreated with GSK3β inhibitors 1 h prior to CK treatment. Cell death and the expression of β-catenin and cyclin D1 were then examined. CK dose- and time-dependently inhibited MCF-7 cell proliferation. Interestingly, CK induced programmed necrosis, but not apoptosis, via the GSK3β signaling pathway in MCF-7 cells. CK inhibited GSK3β phosphorylation, thereby suppressing the expression of β-catenin and cyclin D1. Our results suggest that CK induces programmed necrosis in MCF-7 breast cancer cells via the GSK3β signaling pathway.

DNA damage and inhibition of akt pathway in mcf-7 cells and ehrlich tumor in mice treated with 1,4-naphthoquinones in combination with ascorbate.

The aim of this study was to enhance the understanding of the antitumor mechanism of 1,4-naphthoquinones and ascorbate. Juglone, phenylaminonaphthoquinone-7, and 9 (Q7/Q9) were evaluated for effects on CT-DNA and DNA of cancer cells. Evaluations in MCF-7 cells are DNA damage, ROS levels, viability, and proliferation. Proteins from MCF-7 lysates were immunoblotted for verifying PARP integrity, γH2AX, and pAkt. Antitumor activity was measured in Ehrlich ascites carcinoma-bearing mice. The same markers of molecular toxicity were assessed in vivo. The naphthoquinones intercalate into CT-DNA and caused oxidative cleavage, which is increased in the presence of ascorbate. Treatments caused DNA damage and reduced viability and proliferation of MCF-7 cells. Effects were potentiated by ascorbate. No PARP cleavage was observed. Naphthoquinones, combined with ascorbate, caused phosphorylation of H2AX and inhibited pAkt. ROS were enhanced in MCF-7 cells, particularly by the juglone and Q7 plus ascorbate. Ehrlich carcinoma was inhibited by juglone, Q7, or Q9, but the potentiating effect of ascorbate was reproduced in vivo only in the cases of juglone and Q7, which caused up to 60% inhibition of tumor and the largest extension of survival. Juglone and Q7 plus ascorbate caused enhanced ROS and DNA damage and inhibited pAkt also in Ehrlich carcinoma cells.

Differential effects of baicalein and its sulfated derivatives in inhibiting proliferation of human breast cancer MCF-7 cells

This study was to investigate the anticancer effects of baicalein (Bai) and its two sulfated derivatives, namely baicalein-7-O-sulfate (BoS) and baicalein-8-sodium sulfonate (BcS). BcS was shown to exhibit stronger growth inhibition against human breast cancer MCF-7 cells, compared with structurally related Bai and BoS, where IC50 values of BoS, Bai and BcS were 97.7, 68.3 and 30.4μM, respectively. BoS, Bai and BcS were further shown to mediate the cell-cycle arrest principally in G0/G1-phase within 12h of treatment with MCF-7 cells, and after 12h, they arrested principally in S-phase. It was also found that 17.7%, 44.9% and 70.5% of MCF-7 cells entered the early phase of apoptosis when treated with 200μM BoS, Bai and BcS for 24h, followed by an intracellular ROS generation. BcS displays strong antitumor effect through ROS-dependent apoptosis pathway in MCF-7 cells, and has promising potential to be developed as an antitumor compound.

Hormone replacement therapy enhances IGF-1 signaling in skeletal muscle by diminishing miR-182 and miR-223 expressions: a study on postmenopausal monozygotic twin pairs.

MiRNAs are fine-tuning modifiers of skeletal muscle regulation, but knowledge of their hormonal control is lacking. We used a co-twin case–control study design, that is, monozygotic postmenopausal twin pairs discordant for estrogen-based hormone replacement therapy (HRT) to explore estrogen-dependent skeletal muscle regulation via miRNAs. MiRNA profiles were determined from vastus lateralis muscle of nine healthy 54–62-years-old monozygotic female twin pairs discordant for HRT (median 7 years). MCF-7 cells, human myoblast cultures and mouse muscle experiments were used to confirm estrogen’s causal role on the expression of specific miRNAs, their target mRNAs and proteins and finally the activation of related signaling pathway. Of the 230 miRNAs expressed at detectable levels in muscle samples, qPCR confirmed significantly lower miR-182, miR-223 and miR-142-3p expressions in HRT using than in their nonusing co-twins. Insulin/IGF-1 signaling emerged one common pathway targeted by these miRNAs. IGF-1R and FOXO3A mRNA and protein were more abundantly expressed in muscle samples of HRT users than nonusers. In vitro assays confirmed effective targeting of miR-182 and miR-223 on IGF-1R and FOXO3A mRNA as well as a dose-dependent miR-182 and miR-223 down-regulations concomitantly with up-regulation of FOXO3A and IGF-1R expression. Novel finding is the postmenopausal HRT-reduced miRs-182, miR-223 and miR-142-3p expression in female skeletal muscle. The observed miRNA-mediated enhancement of the target genes’ IGF-1R and FOXO3A expression as well as the activation of insulin/IGF-1 pathway signaling via phosphorylation of AKT and mTOR is an important mechanism for positive estrogen impact on skeletal muscle of postmenopausal women.

Knockdown of EpCAM enhances the chemosensitivity of breast cancer cells to 5-fluorouracil by downregulating the antiapoptotic factor Bcl-2.

Resistance to fluoropyrimidine-based chemotherapy is the main reason for the failure of cancer treatment, and drug resistance is associated with an inability of tumor cells to undergo apoptosis in response to treatment. Alterations in the expression of epithelial cell adhesion molecule (EpCAM) affect the sensitivity or resistance of tumor cells to anticancer treatment and the activity of intracellular signaling pathways. However, the role of EpCAM in the induction of apoptosis in breast cancer cells remains unclear. Here, we investigated the effect of EpCAM gene knockdown on chemosensitivity to 5-fluorouracil (5-FU) in MCF-7 cells and explored the underlying mechanisms. Our results showed that knockdown of EpCAM promoted apoptosis, inhibited cell proliferation and caused cell-cycle arrest. EpCAM knockdown enhanced the cytotoxic effect of 5-FU, promoting apoptosis by downregulating the expression of the anti-apoptotic protein Bcl-2 and upregulating the expression of the pro-apoptotic proteins Bax, and caspase3 via the ERK1/2 and JNK MAPK signaling pathways in MCF-7 cells. These results indicate that knockdown of EpCAM may have a tumor suppressor effect and suggest EpCAM as a potential target for the treatment of breast cancer.

Induction of apoptosis by a peptide from Porphyra yezoensis: regulation of the insulin-like growth factor I receptor signaling pathway in MCF-7 cells.

This study examined how PPY, a peptide from Porphyra yezoensis, regulates multiple cell growth-related signaling pathways in MCF-7 cells. This study determined that PPY induces cell cycle arrest and inhibits the IGF-IR signaling pathway. Cell proliferation studies revealed that PPY induced cell death in a dose-dependent manner. Expression levels of IGF-IR were decreased in MCF-7 cells by PPY in a dose-dependent manner. These results indicate that inhibition of the IGF-IR pathway is also involved in PPY induced proliferation of MCF-7 cells. In addition, these data demonstrated that PPY induces cell cycle arrest and activates apoptosis.

Saussurea lappa extract suppresses TPA-induced cell invasion via inhibition of NF-κB-dependent MMP-9 expression in MCF-7 breast cancer cells.

BackgroundSaussurea lappa (SL) has been used as a traditional herbal medicine to treat abdominal pain and tenesmus, and has been suggested to possess various biological activities, including anti-tumor, anti-ulcer, anti-inflammatory, anti-viral, and cardiotonic activities. The effect of SL on breast cancer metastasis, however, is unknown. Cell migration and invasion are crucial in neoplastic metastasis. Matrix metalloproteinase-9 (MMP-9), which degrades the extracellular matrix, is a major component in cancer cell invasion.MethodsCell viability was examined by MTT assay, whereas cell motility was measured by invasion assay. Western blot, Real-time PCR, and Zymography assays were used to investigate the inhibitory effects of ESL on matrix metalloproteinase-9 (MMP-9) expression level in MCF-7 cells. EMSA confirmed the inhibitory effects of ESL on DNA binding of NF- κB in MCF-7 cells.ResultsCells threated with various concentrations of Saussurea lappa (ESL) for 24 h. Concentrations of 2 or 4 μM did not lead to a significant change in cell viability or morphology. Therefore, subsequent experiments utilized the optimal non-toxic concentration (2 or 4 μM) of ESL. In this study, we investigated the inhibitory effect of ethanol extract of ESL on MMP-9 expression and cell invasion in 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced MCF-7 cells. ESL inhibited the TPA-induced transcriptional activation of nuclear factor-kappa B (NF-κB). However, this result obtained that ESL did not block the TPA-induced phosphorylation of the kinases: p38, ERK, and JNK. Therefore, ELS-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involves the suppression of NF-kB pathway in MCF-7 cells.ConclusionsThese results indicate that ELS-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involves the suppression of NF-kB pathway in MCF-7 cells. Thus, ESL has potential for controlling breast cancer invasiveness in vitro.

The apoptotic effect of ramalin on human breast cancer cells (657.11)

Ramalin is the compound isolated from Antarctic lichen, Ramalina terebrata. Previous study showed that ramalin has antioxidant and anti‐inflammatory activity. However, the effect of ramalin on MCF‐7 human cancer cells has not been addressed. We investigated the effect of ramalin on cell proliferation, apoptosis, and its mechanism in MCF‐7 cells. MTT assay and western blotting showed that ramalin decreased concentration‐dependently cell proliferation, induced apoptosis related proteins (Bax, Bid, AIF), and activated caspase‐3 and 8, respectively. In addition, Annexin V/PI analysis revealed that apoptotic cells were remarkably increased in ramalin‐treated MCF‐7. Our data also showed that ramalin increased phosphorylation of ERK1/2, p38 and JNK in a concentration‐ and time‐dependent manner. Taken together, ramalin induces apoptosis through Mitogen‐activated protein kinases (MAPKs) and caspase dependent signaling pathways in MCF‐7 cells and may be a potential anticancer agent for the treatment of human breast cancer.

Decursin prevents TPA-induced invasion through suppression of PKCα/p38/NF-κB-dependent MMP-9 expression in MCF-7 human breast carcinoma cells

Decursin, a coumarin compound, was first isolated from the roots of Angelica gigas almost four decades ago. It was found to exhibit cytotoxicity against various human cancer cells and to possess anti-amnesic activity in vivo through the inhibition of AChE activity. However, the effect of decursin on breast cancer invasion is unknown. Matrix metalloproteinase-9 (MMP-9) is known to be an important factor for cancer cell invasion. Therefore, in this study, we investigated the inhibitory effect of decursin on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced MMP-9 expression and cell invasion, as well as the molecular mechanisms involved in MCF-7 cells. Our results showed that decursin inhibits TPA-induced MMP-9 expression and cell invasion through the suppression of NF-κB. Furthermore, decursin repressed the TPA-induced phosphorylation of p38 MAPK and inhibited TPA-induced translocation of PKCα from the cytosol to the membrane, but did not affect the translocation of PKCδ. These results indicate that decursin-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involves the suppression of the PKCα, MAPK and NF-κB pathways in MCF-7 cells. Thus, decursin may have potential value in restricting breast cancer metastasis.