The introduction of simian virus 40 large T antigen (SVLT) into human primary cells enables them to proliferate beyond their normal replicative life span. In most cases, this temporary escape from senescence eventually ends in a second proliferative block known as "crisis," during which the cells cease growing or die. Rare immortalization events in which cells escape crisis are frequently correlated with the presence of telomerase activity. We tested the hypothesis that telomerase activation is the critical step in the immortalization process by studying the effects of telomerase activity in two mortal SVLT-Ras val12 -transformed human pancreatic cell lines, TRM-6 and ␤lox5. The telomerase catalytic subunit, hTRT, was introduced into late-passage cells via retroviral gene transfer. Telomerase activity was successfully induced in infected cells, as demonstrated by a telomerase repeat amplification protocol assay. In each of nine independent infections, telomerase-positive cells formed rapidly dividing cell lines while control cells entered crisis. Telomere lengths initially increased, but telomeres were then maintained at their new lengths for at least 20 population doublings. These results demonstrate that telomerase activity is sufficient to enable transformed cells to escape crisis and that telomere elongation in these cells occurs in a tightly regulated manner.

Ataxia-telangiectasia (A-T) is an autosomal recessive disease characterized by progressive cerebellar degeneration, immunode®ciencies, genomic instability and gonadal atrophy. A-T patients are hypersensitive to ionizing radiation and have an elevated cancer risk. Cells derived from A-T patients require higher levels of serum factors, exhibit cytoskeletal defects and undergo premature senescence in culture. We show here that expression of the catalytic subunit of telomerase (hTERT) in primary A-T patient ®broblasts can rescue the premature senescence phenotype. Ectopic expression of hTERT does not rescue the radiosensitivity or the telomere fusions in A-T ®broblasts. The hTERT+AT cells also retain the characteristic defects in cell-cycle checkpoints, and show increased chromosome damage before and after ionizing radiation. Although A-T patients have an increased susceptibility to cancer, the expression of hTERT in A-T ®broblasts does not stimulate malignant transformation. These immortalized A-T cells provide a more stable cell system to investigate the molecular mechanisms underlying the cellular phenotypes of Ataxia-telangiectasia. Oncogene (2001) 20, 278 ± 288.

Cell transplantation therapy for diabetes is limited by an inadequate supply of cells exhibiting glucose-responsive insulin secretion. To generate an unlimited supply of human beta-cells, inducibly transformed pancreatic beta-cell lines have been created by expression of dominant oncogenes. The cell lines grow indefinitely but lose differentiated function. Induction of beta-cell differentiation was achieved by stimulating the signaling pathways downstream of the transcription factor PDX-1, cell-cell contact, and the glucagon-like peptide (GLP-1) receptor. Synergistic activation of those pathways resulted in differentiation into functional beta-cells exhibiting glucose-responsive insulin secretion in vitro. Both oncogene-expressing and oncogene-deleted cells were transplanted into nude mice and found to exhibit glucose-responsive insulin secretion in vivo. The ability to grow unlimited quantities of human beta-cells is a major step toward developing a cell transplantation therapy for diabetes.

With the completion of the Human Genome Project and advances in genomic sequencing technologies, the use of clinical molecular diagnostics has grown tremendously over the last decade. Next-generation sequencing (NGS) has overcome many of the practical roadblocks that had slowed the adoption of molecular testing for routine clinical diagnosis. In endocrinology, targeted NGS now complements biochemical testing and imaging studies. The goal of this review is to provide clinicians with a guide to the application of NGS to genetic testing for endocrine conditions, by compiling a list of established gene mutations detectable by NGS, and highlighting key phenotypic features of these disorders. As we outline in this review, the clinical utility of NGS-based molecular testing for endocrine disorders is very high. Identifying an exact genetic etiology improves understanding of the disease, provides clear explanation to families about the cause, and guides decisions about screening, prevention and/or treatment.

Objectives To explore the relations of parent-child cardiometabolic risk factors and assess the influence of adiposity on these associations. Study design Associations of adiposity, blood pressure, lipids, fasting insulin and glucose, and a risk factor cluster score were evaluated in a cross-sectional study of 179 parents and their children (6–18 years, N=255). Insulin resistance was assessed by euglycemic clamp in parents and children aged 10 or older. Metabolic syndrome in parents was defined by ATPIII criteria. Cluster scores of the risk factors were created based on age-specific z-scores. Analyses included Pearson correlation and linear regression, adjusted for parent and child age, sex, race, and body mass index (BMI), accounting for within-family correlation. Results We found positive parent-child correlations for measures of adiposity (BMI, BMI percentile, waist, subcutaneous fat, and visceral fat; r=0.22–0.34, all p≤0.003), systolic blood pressure (SBP) (r=0.20, p=0.002), total cholesterol (r=0.39, p<0.001), low-density lipoprotein cholesterol (r=0.34, p<0.001), high density lipoprotein cholesterol (r=0.26, p<0.001) triglycerides (r=0.19, p=0.01) and insulin sensitivity (r=0.22, p=0.02) as well as cluster scores (r=0.15, p=0.02). After adjustment for BMI all parent-child correlations, except systolic blood pressure, remained significant. Conclusions Although adiposity is strongly correlated between parents and children, many cardiometabolic risk factors correlate independent of parent and child BMI. Adverse parental cardiometabolic profiles may identify at-risk children independent of the child’s adiposity status.