Ligand-specific sequential regulation of transcription factors for differentiation of MCF-7 cells

<p>Abstract</p> <p>Background</p> <p>Sharing a common ErbB/HER receptor signaling pathway, heregulin (HRG) induces differentiation of MCF-7 human breast cancer cells while epidermal growth factor (EGF) elicits proliferation. Although cell fates resulting from action of the aforementioned ligands completely different, the respective gene expression profiles in early transcription are qualitatively similar, suggesting that gene expression during late transcription, but not early transcription, may reflect ligand specificity. In this study, based on both the data from time-course quantitative real-time PCR on over 2,000 human transcription factors and microarray of all human genes, we identified a series of transcription factors which may control HRG-specific late transcription in MCF-7 cells.</p> <p>Results</p> <p>We predicted that four transcription factors including EGR4, FRA-1, FHL2, and DIPA should have responsibility of regulation in MCF-7 cell differentiation. Validation analysis suggested that one member of the activator protein 1 (AP-1) family, <it>FOSL-1 </it>(FRA-1 gene), appeared immediately following <it>c-FOS </it>expression, might be responsible for expression of transcription factor <it>FHL2 </it>through activation of the AP-1 complex. Furthermore, RNAi gene silencing of <it>FOSL-1 </it>and <it>FHL2 </it>resulted in increase of extracellular signal-regulated kinase (ERK) phosphorylation of which duration was sustained by HRG stimulation.</p> <p>Conclusion</p> <p>Our analysis indicated that a time-dependent transcriptional regulatory network including c-FOS, FRA-1, and FHL2 is vital in controlling the ERK signaling pathway through a negative feedback loop for MCF-7 cell differentiation.</p

Potential utility of eGFP-expressing NOG mice (NOG-EGFP) as a high purity cancer sampling system

<p>Abstract</p> <p>Purpose</p> <p>It is still technically difficult to collect high purity cancer cells from tumor tissues, which contain noncancerous cells. We hypothesized that xenograft models of NOG mice expressing enhanced green fluorescent protein (eGFP), referred to as NOG-EGFP mice, may be useful for obtaining such high purity cancer cells for detailed molecular and cellular analyses.</p> <p>Methods</p> <p>Pancreato-biliary cancer cell lines were implanted subcutaneously to compare the tumorigenicity between NOG-EGFP mice and nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice. To obtain high purity cancer cells, the subcutaneous tumors were harvested from the mice and enzymatically dissociated into single-cell suspensions. Then, the cells were sorted by fluorescence-activated cell sorting (FACS) for separation of the host cells and the cancer cells. Thereafter, the contamination rate of host cells in collected cancer cells was quantified by using FACS analysis. The viability of cancer cells after FACS sorting was evaluated by cell culture and subsequent subcutaneous reimplantation in NOG-EGFP mice.</p> <p>Results</p> <p>The tumorigenicity of NOG-EGFP mice was significantly better than that of NOD/SCID mice in all of the analyzed cell lines (<it>p</it> < 0.01). Sorting procedures enabled an almost pure collection of cancer cells with only slight contamination by host cells. Reimplantation of the sorted cancer cells formed tumors again, which demonstrated that cell viability after sorting was well maintained.</p> <p>Conclusions</p> <p>This method provides a novel cancer sampling system for molecular and cellular analysis with high accuracy and should contribute to the development of personalized medicine.</p

Predictive Value of Localized Stenosis of the Main Pancreatic Duct for Early Detection of Pancreatic Cancer

Background/Aims: In this study, we aimed to evaluate the predictive value of localized stenosis of the main pancreatic duct (MPD) for early detection of pancreatic cancer. Methods: Among 689 patients who underwent endoscopic retrograde pancreatography from January 2008 to September 2018, 19 patients with MPD findings were enrolled. These patients showed findings for indicating suspicious pancreatic cancer at an early stage (FiCE); FiCE was defined as a single, localized stenosis in the MPD without a detectable mass (using any other imaging methods) and without other pancreatic diseases, such as definite chronic pancreatitis, intraductal papillary mucinous neoplasm, and autoimmune pancreatitis. Final diagnoses were established by examining resected specimens or through follow-up examinations after an interval of >5 years. Results: Among 19 patients with FiCE, 11 underwent surgical resection and 8 were evaluated after a >5-year observation period. The final diagnosis of the MPD stenosis was judged to be pancreatic cancer in 9 patients (47%), including 3 with intraepithelial cancer, and to be a non-neoplastic change in 10. The sensitivity, specificity, and accuracy of preoperative pancreatic juice cytology were 75%, 100%, and 88%, respectively. Conclusions: The predictive value of FiCE for pancreatic cancer prevalence was 47%. Histological confirmation with pancreatic juice cytology is necessary before surgical resection