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ID4 gene is a member of the inhibitor of DNA binding (ID) family proteins that inhibit DNA binding of basic helix-loop-helix transcription factors. The epigenetic inactivation of ID4 gene on colorectal cancer (CRC) development and its clinical significance was assessed.', 'In CRC cell lines, ID4 methylation status of the promoter region was assessed by methylation-specific PCR and bisulfite sequencing. The mRNA expression level was assessed by quantitative real-time reverse transcription-PCR. The methylation status of 9 normal epithelia, 13 adenomas, 92 primary CRCs, and 26 liver metastases was assessed by methylation-specific PCR. ID4 protein expression was assessed by immunohistochemistry analysis of tissue specimen.', 'CRC cell lines were shown to be hypermethylated, and mRNA expression was suppressed and could be restored by 5-aza-cytidine treatment. In clinical specimens from normal epithelia, adenomas, primary CRCs, and liver metastases, the frequency of ID4 hypermethylation was 0 of 9 (0%), 0 of 13 (0%), 49 of 92 (53%), and 19 of 26 (73%), respectively, with a significant elevation according to CRC pathological progression. Methylation status of primary CRCs significantly correlated with histopathological tumor grade (P = 0.028). Immunohistochemistry analysis showed ID4 expression of normal colon epithelia, adenomas, and unmethylated primary CRCs but not hypermethylated CRC specimens. Among 76 American Joint Committee on Cancer stage I to IV patients who had undergone curative surgical resection, overall survival was significantly poorer in patients with hypermethylated ID4 bearing tumors (P = 0.0066).
Does epigenetic inactivation of ID4 in colorectal carcinomas correlate with poor differentiation and unfavorable prognosis?

P2X1 receptors play an important role in platelet function as they can induce shape change, granule centralization and are also involved in thrombus formation. As platelets have no nuclei, the level of P2X1 expression depends on transcriptional regulation in megakaryocytes, the platelet precursor cell. Since nothing is known about the molecular mechanisms regulating megakaryocytic P2X1 expression, this study aimed to identify and functionally characterize the P2X1 core promoter utilized in the human megakaryoblastic cell line MEG-01.', 'In order to identify cis-acting elements involved in the transcriptional regulation of P2X1 expression, the ability of 4.7 kb P2X1 upstream sequence to drive luciferase reporter gene expression was tested. Low promoter activity was detected in proliferating MEG-01 cells. This activity increased 20-fold after phorbol-12-myristate-13-acetate (PMA) induced differentiation. A transcription start site was detected 365 bp upstream of the start codon by primer extension. Deletion analysis of reporter constructs indicated a core promoter located within the region -68 to +149 bp that contained two Sp1 sites (named Sp1a and Sp1b) and an NF-1 site. Individual mutations of Sp1b or NF-1 binding sites severely reduced promoter activity whereas triple mutation of Sp1a, Sp1b and NF-1 sites completely abolished promoter activity in both untreated and PMA treated cells. Sp1/3 and NF-1 proteins were shown to bind their respective sites by EMSA and interaction of Sp1/3, NF-1 and TFIIB with the endogenous P2X1 core promoter in MEG-01 cells was demonstrated by chromatin immunoprecipitation. Alignment of P2X1 genes from human, chimp, rat, mouse and dog revealed consensus Sp1a, Sp1b and NF-1 binding sites in equivalent positions thereby demonstrating evolutionary conservation of these functionally important sites.
Do sp1/3 and NF-1 mediate basal transcription of the human P2X1 gene in megakaryoblastic MEG-01 cells?

Optical techniques are routinely used to size and count extracellular vesicles (EV). For comparison of data from different methods and laboratories, suitable calibrators are essential. A suitable calibrator must have a refractive index (RI) as close to that of EV as possible but the RI of EV is currently unknown. To measure EV, RI requires accurate knowledge of size and light scattering. These are difficult to measure as most EVs cannot be resolved by light microscopy and their diameter is smaller than the wavelength of visible light. However, nanoparticle tracking analysis (NTA) provides both size and relative light scattering intensity (rLSI) values. We therefore sought to determine whether it was possible to use NTA to measure the RI of individual EVs.', 'NTA was used to measure the rLSI and size of polystyrene and silica microspheres of known size and RI (1.470 and 1.633, respectively) and of EV isolated from a wide range of cells. We developed software, based on Mie scattering code, to calculate particle RI from the rLSI data. This modelled theoretical scattering intensities for polystyrene and silica microspheres of known size (100 and 200 nm) and RI. The model was verified using data from the polystyrene and silica microspheres. Size and rLSI data for each vesicle were processed by the software to generate RI values.', 'The following modal RI measurements were obtained: fresh urinary EV 1.374, lyophilised urinary EV 1.367, neuroblastoma EV 1.393, blood EV 1.398, EV from activated platelets 1.390, small placental EV 1.364-1.375 and 1.398-1.414 for large placental EV (>200 nm). Large placental EV had a significantly higher RI than small placental EV (p<0.0001). The spread of RI values was narrower for small EV than for the more heterogeneous large EV.
Does measurement of refractive index by nanoparticle tracking analysis reveal heterogeneity in extracellular vesicles?