BackgroundBreast cancer is the most common malignancy among women worldwide in terms of incidence and mortality. About 10% of North American women will be diagnosed with breast cancer during their lifetime and 20% of those will die of the disease. Breast cancer is a heterogeneous disease and biomarkers able to correctly classify patients into prognostic groups are needed to better tailor treatment options and improve outcomes. One powerful method used for biomarker discovery is sample screening with mass spectrometry, as it allows direct comparison of protein expression between normal and pathological states. The purpose of this study was to use a systematic and objective method to identify biomarkers with possible prognostic value in breast cancer patients, particularly in identifying cases most likely to have lymph node metastasis and to validate their prognostic ability using breast cancer tissue microarrays.Methods and FindingsDifferential proteomic analyses were employed to identify candidate biomarkers in primary breast cancer patients. These analyses identified decorin (DCN) and endoplasmin (HSP90B1) which play important roles regulating the tumour microenvironment and in pathways related to tumorigenesis. This study indicates that high expression of Decorin is associated with lymph node metastasis (p<0.001), higher number of positive lymph nodes (p<0.0001) and worse overall survival (p = 0.01). High expression of HSP90B1 is associated with distant metastasis (p<0.0001) and decreased overall survival (p<0.0001) these patients also appear to benefit significantly from hormonal treatment.ConclusionsUsing quantitative proteomic profiling of primary breast cancers, two new promising prognostic and predictive markers were found to identify patients with worse survival. In addition HSP90B1 appears to identify a group of patients with distant metastasis with otherwise good prognostic features.

Human ferritin H-chain protein (FTH1)-based nanoparticles possess a precisely assembled nanometer-scale structure and high safety. However, their applications for imaging and drug delivery towards cancer cells remain limited due to a lack of target specificity. Epidermal growth factor receptor (EGFR) is overexpressed in many malignant tissues including breast cancer, and has been used as a therapeutic target for cancer treatment. Herein, a genetic method is shown to generate EGF-FTH1 chimeric proteins. EGF-FTH1 nanoparticles with EGF on the surface are then produced. The data demonstrate that EGF-FTH1 nanoparticles, with a small size (11.8 ± 1.8 nm), narrow size distribution, and high biosafety, can specifically bind to and then be taken up by breast cancer MCF-7 cells and MDA-MB-231 cells, but not normal breast epithelial MCF-10A cells. In contrast, binding and absorption of nontargeted ferritin-based nanoparticles to breast cancer cells are negligible. In vivo studies show that EGF-FTH1 nanoparticles are accumulated in breast tumors in a mouse xenograft model. Interestingly, the concentration of EGF-FTH1 nanoparticles in the tumor site is significantly reduced when mice are pretreated with an excess of free EGF. These results imply that EGF-EGFR interaction plays an important role in regulating the tumor retention of EGF-FTH1 nanoparticles.

Metformin is an oral biguanide used for type II diabetes. Epidemiologic studies suggest a link between metformin use and reduced risk of breast and other types of cancers. ErbB2-expressing breast cancer is a subgroup of tumors with poor prognosis. Previous studies demonstrated that metformin is a potent inhibitor of ErbB2-overexpressing breast cancer cells; metformin treatment extends the life span and impedes mammary tumor development in ErbB2 transgenic mice in vivo. However, the mechanisms of metformin associated antitumor activity, especially in prevention models, remain unclear. We report here for the first time that systemic administration of metformin selectively inhibits CD61high /CD49fhigh subpopulation, a group of tumor-initiating cells (TIC) of mouse mammary tumor virus (MMTV)-ErbB2 mammary tumors, in preneoplastic mammary glands. Metformin also inhibited CD61high /CD49fhigh subpopulation in MMTV-ErbB2 tumor-derived cells, which was correlated with their compromised tumor initiation/development in a syngeneic tumor graft model. Molecular analysis indicated that metformin induced downregulation of ErbB2 and EGFR expression and inhibited the phosphorylation of ErbB family members, insulin-like growth factor-1R, AKT, mTOR, and STAT3 in vivo. In vitro data indicate that low doses of metformin inhibited the self-renewal/proliferation of cancer stem cells (CSC)/TICs in ErbB2-over-expressing breast cancer cells. We further demonstrated that the expression and activation of ErbB2 were preferentially increased in CSC/TIC-enriched tumorsphere cells, which promoted their self-renewal/ proliferation and rendered them more sensitive to metformin. Our results, especially the in vivo data, provide fundamental support for developing metformin-mediated preventive strategies targeting ErbB2-associated carcinogenesis.

Using the assay of [³H]ryanodine binding to the sarcoplasmic reticulum, the effect of Zn²⁺ on ryanodine receptors (RyRs) of cardiac muscle was investigated. There was no obvious change in the binding at [Zn²⁺]_f of less than 0.2 µM. However, a decrease of the binding became significant with raising [Zn²⁺]_f to 0.5 µM. The inhibitory effect of Zn²⁺ was [Zn²⁺]_f-dependent, with IC_50/ZnI of 2.1±0.4 µM (mean±S.D.). Scatchard analysis indicates that both an increase of K_d and a decrease of B_max were responsible for Zn²⁺-induced decrease of the binding. The Hill coefficient for this inhibitory effect of Zn²⁺ was between 0.8 and 1.2. The interactions of the effects of Zn²⁺ and various modulators of RyR indicate that the inhibitory effect of Zn²⁺ was mostly mediated through inhibiting Ca²⁺ activation sites (CaA) on RyR. Since the [Zn²⁺]_f dependence was not clearly changed by [Ca²⁺]_f, the inhibitory effect of Zn²⁺ may not be due to competition of Zn²⁺ with Ca²⁺ for CaA and probably is indirect. The inhibitory effect of Zn²⁺ could not be antagonized by 2 mM dithiothreitol, a thiol-reducing agent, suggesting that the binding of Zn²⁺ ions to RyRs of cardiac muscle is not accompanied by obvious change of redox state of the RyRs. In comparison with that seen in skeletal muscle [3], the effects of Zn²⁺ on ryanodine binding to the sarcoplasmic reticulum of cardiac muscle show several distinct differences. It is indicated that the effect of Zn²⁺ on RyRs may be isoform-dependent. The physiological significance of the effects of Zn²⁺ is discussed.

In normal (untreated) rats the mean length ratio of postsynaptic to presynaptic membrane was 2.7 +/- 0.8 for neuromuscular junctions of slow-twitch soleus muscle fibres and 4.2 +/- 1.0 for neuromuscular junctions of fast-twitch extensor digitorum longus muscle fibres; this difference was significant (P less than 0.001). After experimental double innervation by fast and slow muscle nerves for four months, the ratio was (1) 2.9 +/- 0.8 for the original slow-twitch fibre end-plate and 2.8 +/- 0.8 for the newly established one, both not significantly different from that of the normal slow-twitch fibres; and (2) 2.2 +/- 0.5 for the original fast-twitch fibre end-plate and 2.2 +/- 0.7 for the newly established one, both significantly smaller than that of the normal fast-twitch fibres (P less than 0.001). This means that the double innervated slow-twitch muscle fibres retained their original neuromuscular junction type, whereas the doubly-innervated fast-twitch muscle fibres underwent a dramatic transformation of their neuromuscular junction from the fast-muscle to the slow-muscle type. In both doubly innervated fibres, the ultrastructural characteristics of neuromuscular junctions, whether altered or not, were identical at both end-plate regions.

Lipopolysaccharide (LPS), a characteristic component of the outer membrane of Gram-negative bacteria, can be used as an effective biomarker to detect bacterial contamination. Here, we reported a 293/hTLR4A-MD2-CD14 cell-based fluorescent biosensor to detect and identify LPS, which is carried out in a 96-well microplate which is nondestructive, user-friendly, and highly efficient. The promoter sequence of the critical signaling pathway gene ZC3H12A (encoding MCPIP1 protein) and enhanced green fluorescence protein (EGFP) were combined to construct a recombinant plasmid, which was transferred into 293/hTLR4A-MD2-CD14 cells through lipid-mediated, DNA-transfection way. LPS was able to bind to TLR4 and coreceptors-induced signaling pathway could result in green fluorescent protein expression. Results show that stable transfected 293/hTLR4A-MD2-CD14 cells with LPS treatment could be directly and continually observed under a high content screening imaging system. The novel cell-based biosensor detects LPS at low concentration, along with the detection limit of 0.075 μg/mL. The cell-based biosensor was evaluated by differentiating Gram-negative and Gram-positive bacteria and detecting LPS in fruit juices as well. This proposed fluorescent biosensor has potential in sensing LPS optically in foodstuff and biological products, as well as bacteria identification, contributing to the control of foodborne diseases and ensurance of public food safety with its high throughput detection way.

With the use of a [$H]ryanodine binding assay, the modulation of skeletal muscle ryanodine receptor (RyR1) by Zn# + was investigated. In the presence of 100 µM free Ca# + concentration (

Metformin is an oral biguanide used for type II diabetes. Epidemiologic studies suggest a link between metformin use and reduced risk of breast and other types of cancers. erbB-2 expressing breast cancer is a subgroup of tumors with poor prognosis. Previous studies demonstrated that metformin is a potent inhibitor of erbB-2 overexpressing breast cancer cells; metformin treatment extends the life span and impedes mammary tumor development in ErbB-2 transgenic mice in vivo. However, the mechanisms of metformin associated anti-tumor activity, especially in prevention models, remain unclear. In this study, we investigated the mechanisms of metformin associated prevention/inhibition of ErbB-2 mediated breast cancer development by focusing on the potential effect of metformin on tumor initiating cells (TICs)/cancer stem cells (CSCs) in the MMTV-erbB-2 transgenic mouse model and its context with existing in vitro models. We report here for the first time that systemic administration of metformin (250 mg/kg/day, ip, between 8- and 18-week of age) selectively inhibits CD61high/CD49fhigh subpopulation, a group of TICs of MMTV-ErbB-2 mammary tumors, in preneoplastic mammary glands. Metformin also inhibited CD61high/CD49fhigh subpopulation in MMTV-erbB-2 tumor-derived cells, which was correlated with their compromised tumor initiation/development in a syngeneic tumor graft model. Molecular analysis indicated that metformin induced downregulation of erbB-2 and EGFR expression and inhibited the phosphorylation of erbB family members, IGF1R, Akt, mTOR and Stat3 in vivo. In vitro data indicate that low doses (1 mM) of metformin inhibited the self-renewal/proliferation of CSCs/TICs in ErbB-2-overexpressing breast cancer cells. We further demonstrated that the expression and activation of ErbB-2 were preferentially increased in CSC/TIC-enriched tumorsphere cells, which promoted their self-renewal/proliferation and rendered them more sensitive to metformin. Our results, especially the in vivo data, provide fundamental support for developing metformin-mediated preventive strategies targeting erbB-2-associated carcinogenesis. Citation Format: Pei Zhu, Meghan Davis, Amanda Blackwelder, Nora Bachman, Bolin Liu, Susan Edgerton, Leonard L. Williams, Ann D. Thor, Xiaohe Yang. Metformin selectively targets tumor initiating cells in erbb-2 overexpressing breast cancer models. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2967. doi:10.1158/1538-7445.AM2014-2967