Objective The goal of the study was to investigate the genetic and molecular basis of a novel syndrome of marked hyperglucagonemia and pancreatic α cell hyperplasia without glucagonoma syndrome. Methods The glucagon receptor gene (GCGR) and glucagon gene were sequenced in a patient with hyperglucagonemia and pancreatic α cell hyperplasia without glucagonoma syndrome. Enhanced green fluorescent protein (EGFP)-conjugated WT and mutant GCGR were used to characterize the functions of the mutant GCGR. Results The glucagon gene sequence was normal but GCGR sequencing uncovered a homozygous missense mutation, c.256C>T, p.P86S in the extracellular domain of GCGR. When expressed in HEK293 cells, GCGR P86S localized to the plasma membrane but bound 96% less radiolabeled glucagon than WT GCGR. The EC50 of glucagon-induced cAMP production was 24 nM for GCGR P86S but 2.4 nM for WT GCGR. The patient's α cells also express glucagon-like peptide 1 and pancreatic polypeptide. Conclusion We hereby report the first homozygous missense mutation in the human GCGR which is associated with α cell hyperplasia and hyperglucagonemia. This mutation lowers the receptor’s affinity to glucagon and decreases cAMP production with physiological concentrations of glucagon. Thus, the P86S mutation in GCGR likely causes α cells hyperplasia and hyperglucagonemia.

Fig. 6. GH induces EMT, suppresses apoptosis, and increases motility. Western blot analysis of PTEN and EMT factors in (A) hNCC and (B) HCT116 cells treated with indicated doses of GH for 24 h. (C) Western blot analysis of cleaved caspase 3 in cells treated with GH (500 ng/mL) for 24 h. Experiments were performed at least three times, and representative results shown. (D) Migration of hNCC and HCT116 cells treated with GH (500 ng/mL) and harvested 48 h after plating. (E) Migration of HCT116 cocultured for 48 h with hCF infected with lentivector or lentiGH. In D and E, for quantification, the number of migrated cells per 1,000 cells in five randomly chosen fields in each duplicate transwell were counted and means calculated. Results are presented as mean ± SEM of three independent experiments; *P < 0.05. (F) Number of colonies and arbitrary colony size formed in soft agar by HCT116 cells cocultured with hCF infected with lentivector or lentiGH, and tested for anchorage independent growth. Colony size was determined using ImageJ software. Results are presented as mean ± SEM of duplicates from two independent experiments; **P < 0.01 vs. control. In D-F, the differences between groups were analyzed using two-tailed unpaired Student t test.

Cancer is a common cause of death worldwide. Despite significant advances in cancer treatments, the morbidity and mortality are still enormous. Tumor heterogeneity, especially intratumoral heterogeneity, is a significant reason underlying difficulties in tumor treatment and failure of a number of current therapeutic modalities, even of molecularly targeted therapies. The development of a virtually noninvasive “liquid biopsy” from the blood has been attempted to characterize tumor heterogeneity. This review focuses on cell-free circulating tumor DNA (ctDNA) in the bloodstream as a versatile biomarker. ctDNA analysis is an evolving field with many new methods being developed and optimized to be able to successfully extract and analyze ctDNA, which has vast clinical applications. ctDNA has the potential to accurately genotype the tumor and identify personalized genetic and epigenetic alterations of the entire tumor. In addition, ctDNA has the potential to accurately monitor tumor burden and treatment response, while also being able to monitor minimal residual disease, reducing the need for harmful adjuvant chemotherapy and allowing more rapid detection of relapse. There are still many challenges that need to be overcome prior to this biomarker getting wide adoption in the clinical world, including optimization, standardization, and large multicenter trials.

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Esophageal squamous cell carcinoma (ESCC) has a multifactorial etiology involving environmental and/or genetic factors. End-binding protein 1 (EB1), which was cloned as an interacting partner of the adenomatous polyposis coli (APC) tumor suppressor protein, was previously found overexpressed in ESCC. However, the precise role of EB1 in the development of this malignancy has not yet been elucidated. In this study, we analysed freshly resected ESCC specimens and demonstrated that EB1 was overexpressed in approximately 63% of tumor samples compared to matched normal tissue. We report that overexpression of EB1 in the ESCC line EC9706 significantly promotes cell growth, whereas suppression of EB1 protein level by RNA interference significantly inhibited growth of esophageal tumor cells. In addition, EB1 overexpression induced nuclear accumulation of b-catenin and promoted the transcriptional activity of b-catenin/T-cell factor (TCF). These effects were partially or completely abolished by coexpression of APC or DN TCF4, respectively. Also, we found that EB1 affected the interaction between b-catenin and APC. Furthermore, EB1 overexpression was correlated with cytoplasmic/ nuclear accumulation of b-catenin in primary human ESCC. Taken together, these results support the novel hypothesis that EB1 overexpression may play a role in the development of ESCC by affecting APC function and activating the b-catenin/TCF pathway. Oncogene (2005) 24, 6637-6645.

Pituitary tumor transforming gene (PTTG1) was isolated from rat pituitary tumor cells, and subsequently identified as a securin protein as well as a transcription factor. We show here a global transcriptional effect of PTTG1 in human choriocarcinoma JEG-3 cells by simultaneously assessing 20 000 gene promoters using chromatin immunoprecipitation (ChIP)-on-Chip experiments. Seven hundred and forty-six gene promoters (Po0.001) were found enriched, with functions relating to cell cycle, metabolic control and signal transduction. Significant interaction between PTTG1 and Sp1 (Po0.000001) was found by transcriptional pattern analysis of ChIP data and further confirmed by immunoprecipitation and pull-down assays. PTTG1 acts coordinately with Sp1 to induce cyclin D3 expression Bthreefold, and promotes G1/S-phase transition independently of p21. PTTG1 deletion was also protective for anchorage-independent cell colony formation. The results show that PTTG1 exhibits properties of a global transcription factor, and specifically modulates the G1/S-phase transition by interacting with Sp1. This novel signaling pathway may be required for PTTG1 transforming activity.

Overexpression of human pituitary tumor transforming gene (PTTG) is wildly detected in many tumors, including esophageal cancer. Besides overexpression of PTTG in esophageal squamous cell carcinoma (ESCC) tissues and cells, we detected accumulation of cytoplasmic ␤-catenin in ESCC. In our study, a putative TCF4-binding element (TBE) was identified in PTTG promoter region. The activity of PTTG promoter containing the TBE was activated by S37A␤-catenin and inhibited by dominant-negative TCF. Furthermore, the activation by S37A␤-catenin was mostly abrogated among PTTG promoter region without the TBE or with a mutant one. By using biotin-streptavidin pull-down assay, we also found that the TBE among PTTG promoter bound to TCF-4 protein. Moreover, levels of PTTG mRNA and protein were increased by S37A␤-catenin. Finally, it is noticeable that we detected a correlation between ␤-catenin localization and PTTG expression in 69 primary ESCC (p<0.01). In brief, our study shows that overexpression of PTTG in ESCC is likely due to the activation of ␤-catenin/WNT signaling. The human pituitary tumor transforming gene (PTTG), also termed as human securin, was first obtained from fetal liver and identified as an oncogene. 1 The functional mechanism of PTTG in tumorigenesis is still barely understood, but accumulating evidence reveals that PTTG plays crucial roles in cell-cycle progression, appropriate cell division and chromosome stability, in addition to involvement in malignant transformation and tumorigenesis. 2-5 PTTG inhibits sister chromatid separation and is related to cell-cycle control. PTTG expression appears to be cell cycle dependent, reaches peak in mitosis and can be phosphorylated by Cdc2 kinase during mitosis. 6 PTTG, through direct interaction with MEK1, participates in the signaling cascade and can be phosphorylated by MAP kinase. 7 As a cotranscription factor, PTTG interacts with sequence-specific elements in the c-myc promoter and increases cell proliferation, suggesting that PTTG would mediate cellular transformation by activating this oncogene. 8 Moreover, PTTG's interacting with Ku 9 physically and binding to P53 10 suggest that PTTG may take part in DNA-damage-response pathway, DNA repair and apoptosis. 11,12 PTTG induces expression of b-FGF 1 and VEGF, 13 implying that it may play a role in tumor angiogenesis. The expression of PTTG in most normal tissues is very restricted, contrary to that in a number of human tumor tissues, such as pituitary adenomas, 1,14 lung and breast cancers, 14 colorectal tumor 15 and especially in esophageal cancer. 16 Human esophageal cancer is an aggressive tumor with a generally poor prognosis. Esophageal squamous cell carcinoma (ESCC) is the most common subtype of esophageal cancer and has a higher incidence than esophageal adenocarcinomas (EADC) among Chinese population. Although it is widely believed that esophageal cancer arises from multistep genetic and cytogenetic alterations, 17 the mechanisms have yet to be convincingly identified. Molecular studies have revealed f...

To achieve the mission of personalized medicine, centering on delivering the right drug to the right patient at the right dose, therapeutic drug monitoring solutions are necessary. In that regard, wearable biosensing technologies, capable of tracking drug pharmacokinetics in noninvasively retrievable biofluids (e.g., sweat), play a critical role, because they can be deployed at a large scale to monitor the individuals’ drug transcourse profiles (semi)continuously and longitudinally. To this end, voltammetry-based sensing modalities are suitable, as in principle they can detect and quantify electroactive drugs on the basis of the target’s redox signature. However, the target’s redox signature in complex biofluid matrices can be confounded by the immediate biofouling effects and distorted/buried by the interfering voltammetric responses of endogenous electroactive species. Here, we devise a wearable voltammetric sensor development strategy—centering on engineering the molecule–surface interactions—to simultaneously mitigate biofouling and create an “undistorted potential window” within which the target drug’s voltammetric response is dominant and interference is eliminated. To inform its clinical utility, our strategy was adopted to track the temporal profile of circulating acetaminophen (a widely used analgesic and antipyretic) in saliva and sweat, using a surface-modified boron-doped diamond sensing interface (cross-validated with laboratory-based assays, R2 ∼ 0.94). Through integration of the engineered sensing interface within a custom-developed smartwatch, and augmentation with a dedicated analytical framework (for redox peak extraction), we realized a wearable solution to seamlessly render drug readouts with minute-level temporal resolution. Leveraging this solution, we demonstrated the pharmacokinetic correlation and significance of sweat readings.