The forkhead transcription factor FOXN1 is required for normal cutaneous and thymic epithelial development. Mutations in FOXN1 give rise to the nude phenotype in mice, rats and man. However, the genes that are regulated by FOXN1 are unknown. To investigate FOXN1 function we expressed an inducible form of the protein, FOXN1ER, that is activated by 4-hydroxytamoxifen in primary human epidermal keratinocytes. Transient activation of FOXN1 decreased the proportion of keratinocytes that formed actively growing clones attributable to stem cell founders and increased the number of abortive clones, without inducing apoptosis. Within 24 hours the majority of cells had initiated terminal differentiation, as assessed by involucrin expression. We performed a cDNA microarray experiment to analyse changes in the transcription of approximately 6000 genes. Following FOXN1 activation we detected increases of two fold or greater in the RNA levels of over 30 genes. Genes promoting growth arrest, survival and differentiation featured prominently and markers of early events in keratinocyte differentiation were also detected. Since one of the induced genes was Akt we investigated whether Akt played a role in terminal differentiation. Activation of PI 3-kinase but not Akt was necessary for FOXN1-induced differentiation. In reconstituted epidermis FOXN1 promoted early stages of terminal differentiation whereas Akt activation was sufficient to induce late stages, including formation of the cornified layers. These results establish a role for FOXN1 in initiation of terminal differentiation and implicate Akt in subsequent events.

The EMS1 and CCND1 genes at chromosome 11q13 are ampli®ed in about 15% of primary breast cancers but appear to confer dierent phenotypes in ER positive and ER negative tumours. Since there are no published data on EMS1 expression in large series of breast cancers we examined the relationship of EMS1 expression with EMS1 gene copy number and expression of mRNAs for cyclin D1 and ER. In a subset of 129 patients, where matched tumour RNA and DNA was available, EMS1 mRNA overexpression was associated predominantly with gene ampli®cation (P=0.0061), whereas cyclin D1 mRNA overexpression was not (P=0.3142). In a more extensive series of 351 breast cancers, there was no correlation between cyclin D1 and EMS1 expression in the EMS1 and cyclin D1 overexpressors (P=0.3503). Although an association between EMS1 mRNA expression and ER positivity was evident (P=0.0232), when the samples were divided into quartiles of EMS1 or cyclin D1 mRNA expression, the increase in the proportion of ER positive tumours in the ascending EMS1 mRNA quartiles was not statistically signi®cant (P=0.0951). In marked contrast there was a signi®cant stepwise increase in ER positivity in ascending quartiles of cyclin D1 mRNA (P=0.030). A potential explanation for this dierence was provided by the observation that in ER positive breast cancer cells oestradiol treatment resulted in increased cyclin D1 gene expression but was without eect on EMS1. The relationship between EMS1 expression and clinical outcome was examined in a subset of 234 patients with median follow-up of 74 months. High EMS1 expression was associated with age 450 years (P=0.0001), postmenopausal status (P=0.0008), lymph node negativity (P=0.019) and an apparent trend for worse prognosis in the ER negative subgroup. These data demonstrate that overexpression of EMS1 mRNA is largely due to EMS1 gene ampli®ca-tion, is independent of cyclin D1 and ER expression and, in contrast to cyclin D1, is not regulated by oestrogen. Independent overexpression of these genes may confer dierent phenotypes and disease outcomes in breast cancer as has been inferred from recent studies of EMS1 and CCND1 gene ampli®cation.

No abstract

Circulating cancer-derived small extracellular vesicles (EVs) are nanoscale membranous vesicles shed from cancer cells that are released into surrounding body fluids. Small EVs contain biomolecules associated with cancer such as DNA and proteins for cell-to-cell communication. Therefore, small EVs have been regarded as important cancer biomarkers for liquid biopsy-based cancer diagnosis and drug treatment monitoring. However, because of the high heterogeneity and low level of small EVs in body fluids, there is a high demand for sensitive detection and characterization of such vesicles at a molecular level. In this study, we have developed a sensitive and effective approach to simultaneously profile multiple protein biomarkers expressed on cancerderived small EVs using surface-enhanced Raman spectroscopy (SERS) nanotags in a single test, without complex isolation steps. Rapid and multiplexed phenotypic profiling of small EVs is achieved by mixing specific detection antibody-coated SERS nanotags, filtered conditioned EV-suspended medium (conditioned EVs), and capture antibody (CD63)-conjugated magnetic beads to form a sandwich immunoassay. As a proof-ofconcept demonstration, we applied this approach to characterize pancreatic cancer-derived EVs by simultaneously detecting three specific EV surface receptors including Glypican-1, epithelial cell adhesion molecules (EpCAMs), and CD44 variant isoform 6 (CD44V6). The sensitivity of this method was measured down to 2.3 × 10 6 particles/mL, which is more sensitive and shows higher multiplexing capability than most other reported EV profiling techniques, such as western blot, enzyme-linked immunosorbent assay, and flow cytometry. Furthermore, phenotypic profiling of small EVs from colorectal cancer and bladder cancer cell lines (SW480 and C3) was conducted and compared to those derived from pancreatic cancer (Panc-1), highlighting the significant difference in EV phenotypes for various cancer cell types suspended in both phosphate-buffered saline and plasma. Thus, we believe that this technology enables a comprehensive evaluation of small secreted EV heterogeneity with high sensitivity, offering strong potential for accurate noninvasive cancer diagnosis and monitoring of drug treatment. In addition, this assay provides point-of-care use because of the easy sample preparation and portable nature of the Raman spectrometer.

Heregulin-mediated activation of particular erbB receptor combinations was used as a model system to investigate the interaction of erbB3 and erbB4 with the adaptor protein growth factor receptor-bound (Grb)7. In human breast cancer cell lines, co-immunoprecipitation of Grb7 with both receptors was detected upon heregulin stimulation. This association was direct and mediated by the Grb7 Src homology (SH)2 domain. Coexpression of erbB2 with erbB3 point mutants was used to map Grb7 binding sites. This demonstrated that tyrosine 1180 and 1243 represent the major and minor sites of Grb7 interaction, respectively. Although these recognition sequences possess an Asn residue at ؉2 relative to the phosphotyrosine and therefore represent potential Grb2 binding sites, phosphopeptide competition and "pull-down" experiments demonstrated that they interact preferentially with the Grb7 versus the Grb2 SH2 domain. Substitution analysis indicated that an Arg residue at ؉3 could act as a selectivity determinant, but the effect was context-dependent. Consequently, the Grb2 and Grb7 SH2 domains possess overlapping, but distinct, specificities. These studies therefore identify Grb7 as an in vivo target of erbB3 and erbB4 and provide an underlying mechanism for the ability of erbB3 to recruit Grb7 and not Grb2, a property unique among erbB receptors.Recently it has become evident that a complex series of interactions governs signaling by the erbB family of receptor tyrosine kinases. This family currently contains four members, the epidermal growth factor receptor (EGFR) 1 or erbB1, erbB2, erbB3, and erbB4, which differ both qualitatively and quantitatively in their signaling potential (1-3) and biological activities (4 -7). A variety of ligands exhibit distinct specificities for one or more of these receptors. For example, the EGFR possesses multiple ligands, including EGF, transforming growth factor-␣, amphiregulin, and betacellulin, but betacellulin also binds erbB4 (8), and both erbB3 and erbB4 provide receptors for the heregulin/neuregulin 1 and neuregulin 2 families of ligands (9 -16). Furthermore, ligand-induced erbB receptor heterodimerization, first detected between the EGFR and erbB2 (17,18), diversifies the signals that can be generated by particular ligands (6,19,20). Importantly, this occurs in a hierarchical fashion and also with directionality (20). In particular, erbB2-containing heterodimers are preferred, and this receptor favors interaction with erbB3. Moreover, heterodimerization is critical for the activity of the erbB3 receptor because it is kinase-impaired and hence reliant on transphosphorylation by other receptors for signal generation (2, 21-23).Dimerization of erbB receptors leads to kinase activation and phosphorylation of their cytoplasmic domains on specific tyrosine residues, thus creating binding sites for signaling molecules containing phosphotyrosine binding or Src homology (SH) 2 domains (24). The latter are conserved noncatalytic regions of approximately 100 amino acids which, along with other modu...

Prostate cancer is the most frequently diagnosed male visceral cancer and the second leading cause of cancer death in the United States. Standard tests such as prostate-specific antigen (PSA) measurement have poor specificity (33%) resulting in a high number of false positive reports. Consequently there is a need for new biomarkers to address this problem. The MIL-38 antibody was first described nearly thirty years ago, however, until now, the identification of the target antigen remained elusive. By a series of molecular techniques and mass spectrometry, the MIL-38 antigen was identified to be the highly glycosylated proteoglycan Glypican-1 (GPC-1). This protein is present in two forms; a membrane bound core protein of 55-60 kDa and secreted soluble forms of 40 kDa and 52 kDa. GPC-1 identification was confirmed by immuno-precipitation, western blots and ELISA. An ELISA platform is currently being developed to assess the levels of GPC-1 in normal, benign prostatic hyperplasia (BPH) and prostate cancer patients to determine whether secreted GPC-1 may represent a clinically relevant biomarker for prostate cancer diagnosis.

No abstract

During the last decade, isolation of circulating tumour cells via blood liquid biopsy of prostate cancer (PCa) has attracted significant attention as an alternative, or substitute, to conventional diagnostic tests. However, it was previously determined that localised forms of PCa shed a small number of cancer cells into the bloodstream, and a large volume of blood is required just for a single test, which is impractical. To address this issue, urine has been used as an alternative to blood for liquid biopsy as a truly non-invasive, patient-friendly test. To this end, we developed a spiral microfluidic chip capable of isolating PCa cells from the urine of PCa patients. Potential clinical utility of the chip was demonstrated using anti-Glypican-1 (GPC-1) antibody as a model of the primary antibody in immunofluorescent assay for identification and detection of the collected tumour cells. The microchannel device was first evaluated using DU-145 cells in a diluted Dulbecco’s phosphate-buffered saline sample, where it demonstrated >85 (±6) % efficiency. The microchannel proved to be functional in at least 79% of cases for capturing GPC1+ putative tumour cells from the urine of patients with localised PCa. More importantly, a correlation was found between the amount of the captured GPC1+ cells and crucial diagnostic and prognostic parameter of localised PCa—Gleason score. Thus, the technique demonstrated promise for further assessment of its diagnostic value in PCa detection, diagnosis, and prognosis.