Yingnan Yu

National University of Singapore, Tumasik, Singapore

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Publications (7)28.24 Total impact

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    ABSTRACT: Complement component 1, q subcomponent binding protein (C1QBP), is a multi-compartmental protein with higher mRNA expression reported in breast cancer tissues. This study evaluated the association between immunohistochemical expression of the C1QBP protein in breast cancer tissue microarrays (TMAs) and clinicopathological parameters, in particular tumor size. In addition, an in vitro study was conducted to substantiate the breast cancer TMA findings. Breast cancer TMAs were constructed from pathological specimens of patients diagnosed with invasive ductal carcinoma. C1QBP protein and proliferating cell nuclear antigen (PCNA) immunohistochemical analyses were subsequently performed in the TMAs. C1QBP immunostaining was detected in 131 out of 132 samples examined. The C1QBP protein was predominantly localized in the cytoplasm of the breast cancer cells. Univariate analysis revealed that a higher C1QBP protein expression was significantly associated with older patients (P = 0.001) and increased tumor size (P = 0.002). Multivariate analysis showed that C1QBP is an independent predictor of tumor size in progesterone-positive tumors. Furthermore, C1QBP was also significantly correlated with expression of PCNA, a known marker of proliferation. Inhibition of C1QBP expression was performed by transfecting C1QBP siRNA into T47D breast cancer cells, a progesterone receptor-positive breast cancer cell line. C1QBP gene expression was analyzed by real-time RT-PCR, and protein expression by Western blot. Cell proliferation assays were also performed by commercially available assays. Down-regulation of C1QBP expression significantly decreased cell proliferation and growth in T47D cells. Taken together, our findings suggest that the C1QBP protein could be a potential proliferative marker in breast cancer. © 2015 by the Society for Experimental Biology and Medicine.
    Experimental Biology and Medicine 01/2015; 240(7). DOI:10.1177/1535370214565075 · 2.17 Impact Factor
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    ABSTRACT: Aims: Y-box binding protein-1 (YB-1) is known to modulate gene transcription and protein translation, as well as cellular response to drug treatment. The aim of this study is to correlate YB-1 protein expression levels with clinicopathological parameters in intestinal-type gastric cancer tissue samples (as categorized by the Lauren classification) and substantiate the findings with in vitro experimentation. Methods and results: Paraffin-embedded samples from 167 patients with intestinal-type gastric cancer were used for the construction of tissue microarrays (TMAs). TMA slides were immunostained and YB-1 immunoreactivity score was based on the weighted average intensity score. Univariate analysis revealed that YB-1 immunohistochemical expression was correlated significantly with lymph node status (P = 0.054, borderline significance) and perforation (P = 0.043). YB-1 expression was also found to be an independent predictor of lymph node spread by multivariate analysis. Furthermore, siRNA-mediated YB-1 gene knockdown in MKN7 gastric cancer cells (which is known to originate from an intestinal-type gastric cancer tissue) inhibited cell migration (P = 0.0002) and invasion in vitro (P = 0.0129) significantly. Conclusion: YB-1 expression is associated with lymph node spread in intestinal-type gastric cancer and is a potential prognostic biomarker in this subtype of gastric cancer.
    Histopathology 10/2014; 66(4). DOI:10.1111/his.12570 · 3.45 Impact Factor
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    ABSTRACT: Breast cancer metastasis accounts for the majority of deaths from breast cancer. Detection of breast cancer metastasis at the earliest stage is important for the management and prediction of breast cancer progression. Emerging techniques using the analysis of circulating tumor cells show promising results in predicting and identifying the early stages of breast cancer metastasis in patients. Additionally, a deeper understanding of the metastatic cascade in breast cancer will be critical for developing therapeutic interventions to combat breast cancer metastasis. In this review, the current and novel methods for detection of breast cancer metastasis, as well as the mechanisms involved in metastasis and the treatment of breast cancer metastasis, are discussed.
    09/2012; 9(5):311-20.
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    ABSTRACT: DZNep (3-deazaneplanocin A) depletes EZH2, a critical component of polycomb repressive complex 2 (PRC2), which is frequently deregulated in cancer. Despite exhibiting promising anticancer activity, the specific genetic determinants underlying DZNep responsiveness in cancer cells remain largely unknown. We sought to determine molecular factors influencing DZNep response in gastric cancer. Phenotypic effects of DZNep were evaluated in a panel of gastric cancer cell lines. Sensitive lines were molecularly interrogated to identify potential predictors of DZNep responsiveness. The functional importance of candidate predictors was evaluated using short hairpin RNA (shRNA) and siRNA technologies. DZNep depleted PRC2 pathway components in almost all gastric cancer lines, however, only a subset of lines exhibited growth inhibition upon treatment. TP53 genomic status was significantly associated with DZNep cellular responsiveness, with TP53 wild-type (WT) lines being more sensitive (P < 0.001). In TP53-WT lines, DZNep stabilized p53 by reducing ubiquitin conjugation through USP10 upregulation, resulting in activation of canonical p53 target genes. TP53 knockdown in TP53-WT lines attenuated DZNep sensitivity and p53 target activation, showing the functional importance of an intact p53 pathway in regulating DZNep cellular sensitivity. In primary human gastric cancers, EZH2 expression was negatively correlated with p53 pathway activation, suggesting that higher levels of EZH2 may repress p53 activity. Our results highlight an important role for TP53 genomic status in influencing DZNep response in gastric cancer. Clinical trials evaluating EZH2-targeting agents such as DZNep should consider stratifying patients with gastric cancer by their TP53 genomic status.
    Clinical Cancer Research 06/2012; 18(15):4201-12. DOI:10.1158/1078-0432.CCR-12-0036 · 8.72 Impact Factor
  • Ikuyo Inoue · Ken Matsumoto · Yingnan Yu · Boon-Huat Bay ·
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    ABSTRACT: The Y-box binding protein 1 (YB-1), characterized by the presence of the cold shock domain, has been reported to induce chemoresistance in cancer therapy. Chemotherapy is one of the main therapeutic strategies in the treatment of cancer, in addition to surgery, radiation therapy, and hormonal therapy. However, chemoresistance remains a key obstacle to successful cancer management. In this review, we will focus on the role of YB-1, an important regulator of gene transcription, in cancer therapy and chemoresistance.
    The Anatomical Record Advances in Integrative Anatomy and Evolutionary Biology 02/2012; 295(2):215-22. DOI:10.1002/ar.22401 · 1.54 Impact Factor

  • Cancer Research 01/2011; 70(8 Supplement):2248-2248. DOI:10.1158/1538-7445.AM10-2248 · 9.33 Impact Factor
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    ABSTRACT: Peroxiredoxin III (Prx III), an antioxidant protein found in mitochondria, plays an essential role in mitochondrial homeostasis. Aberrant expression of Prx III has been implicated in the tumorigenesis of various cancers. In this study, we evaluated the expression of Prx III in breast cancer tissues and elucidated its role in cell proliferation, a hallmark of cancer. Breast tissue microarrays comprising 106 breast cancer sections were stained with Prx III antibody using immunohistochemisty and correlated with proliferating cell nuclear antigen (PCNA) immunostaining. To validate the role of Prx III in cell proliferation, expression of Prx III was analyzed at the mRNA and protein levels by real-time RT-PCR, Western blotting and immunofluorescence in vitro. siRNA mediated silencing of Prx III in MDA-MB-231 breast cancer cells was performed and the effect on the cell cycle was examined. Prx III expression in patient tissue microarray samples was found to be positively associated with PCNA immunostaining, a proliferative marker. Prx III was expressed in both MCF-7 and MDA-MB-231 breast cancer cell lines and transient transfection with siPrx III in MDA-MB-231 cells induced inhibition of cell proliferation and cell cycle arrest. The data suggests that Prx III has a significant role in cell cycle regulation and could be a potential proliferation marker in breast cancer.
    International Journal of Oncology 02/2010; 36(2):359-64. DOI:10.3892/ijo_00000507 · 3.03 Impact Factor