p53 mutations in prostate cancer bone metastases suggest that selected p53 mutants in the primary site define foci with metastatic potential

PURPOSE: This study was undertaken to establish the pattern of specific p53 gene mutations in prostate cancer within primary tumors and distant metastases. MATERIALS AND METHODS: We performed polymerase chain reaction-single-strand conformation polymorphism and sequencing analyses of p53 exons 5-8 in DNA extracted from 22 formalin-fixed, paraffin-embedded tissues from 17 patients. Samples from three patients included specimens from primary and metastatic sites (paired specimens). RESULTS: G:C-to-A:T transitions were the most common point mutations (64%). Six (55%) of 11 G:C-to-A:T transitions occurred at CpG dinucleotides in five hot-spot codons (175, 245, 248, 273, and 282). Sequencing analysis of the paired samples revealed that two of the three pairs had the same mutation in both. Sequencing analysis of DNA from a different area of one of the primary tumors revealed a different mutation in the p53 gene. CONCLUSIONS: Our results suggest that specific p53 mutations participate in the progression of human prostate cancer. These findings support those of others that indicate that the primary cancer is heterogeneous and clonal expansion occurs during the progression of clinically detectable prostate cancer. Our data also imply that p53 mutations at the primary site may be predictive of metastases.     

Two mutations identified in the androgen receptor of the new human prostate cancer cell line MDA PCa 2a

PURPOSE: We have characterized the androgen receptor (AR) in a new human prostate cancer cell line, MDA PCa 2a, that has recently been established from a bone metastasis of a patient whose cancer exhibited androgen-independent growth. MATERIALS AND METHODS: Androgen responsiveness of these cells was assessed by measuring the effect of DHT and R1881 on cell growth and PSA secretion. Scatchard analysis was used to characterize the affinity and abundance of AR protein. Using a PCR based strategy, genomic DNA of the entire coding region of AR gene was sequenced to identify possible mutations. RESULTS: These cells express abundant AR (Nmax = 685 +/- 149 fmol./mg. protein), but the AR binding affinity (Kd) for DHT is only 25 nM, approximately 50-fold lower affinity than the mutated AR in LNCaP prostate cancer cells (Kd = 0.5 nM) or the wildtype AR in MCF-7 breast cancer cells (Kd = 0.4 nM). Two mutations, L701H and T877A, were identified in the ligand binding domain of the AR gene. Compared with LNCaP cells, the new cell line is significantly less responsive to DHT and R1881 as well as to other androgens such as testosterone, androstenedione, and DHEA. Similar to LNCaP cells, the ligand specificity of the AR in MDA PCa 2a cells appears to be relaxed and non-androgens such as progesterone and estradiol act as agonists although with less potency than in LNCaP cells. Interestingly, in the absence of androgens, the new cell line expresses 15-fold higher baseline levels of PSA than LNCaP. CONCLUSIONS: Two mutations were identified in the AR gene of the MDA PCa 2a cell line that are likely responsible for the decreased androgen sensitivity and altered ligand specificity observed in these cells. Thus, this new cell line with partial androgen responsiveness and PSA expression can serve as a functionally relevant model system of bone metastatic prostate cancer, and can be used to investigate the role of AR mutations in prostate cancer and its progression to androgen independence.     

Impairment of lymphocyte suppressive system in recent onset insulin-dependent diabetes mellitus. correlation with blood glucose and serum insulin levels

Summary In a previous study, we observed an impairment of the theophylline-induced suppressive system in recent onset IDDM patients, and demonstrated also a correlation with metabolic derangement. The aim of this study was to better investigate the relationship between theophylline sensitivity (ThS) and blood glucose/plasma insulin levels in recent onset IDDM patients subjected to preprogrammed variations by an insulin/glucose clamp with artificial pancreas. Eight patients were studied within 8 weeks from the onset of IDDM. ThS was evaluated as the ability of theophylline to inhibit blastogenic response of peripheral blood lymphocytes (PBL) to Concanavalin A (ConA), after 120 min preincubation of the cells. All patients were connected to an artificial pancreas. Through i.v. continuous insulin infusion (0.02 U/kg/h) and/or i.v. continuous glucose and saline infusion, the following experimental conditions, lasting at least 1h, were obtained: T1: relative euglycemia and normal insulinemia; T2: relative euglycemia and hyperinsulinemia; T3: hyperglycemia and normal insulinemia; T4: hyperglycemia and hyperinsulinemia. ThS was maintained in 6/8 patients at T1 and in 8/8 patients at T4. ThS was lost in 4/8 patients at T2 and T3. These data suggest that the loss of ThS induced by hyperglycemia can be corrected by hyperinsulinemia, and that it is maintained when euglycemia is accompained by hypoinsulinemia. It is lost when these two parameters lose their interrelationship.     

In vitro and in vivo studies of a VEGF121/rGelonin chimeric fusion toxin targeting the neovasculature of solid tumors

Vascular endothelial growth factor (VEGF) plays a key role in the growth and metastasis of solid tumors. We generated a fusion protein containing VEGF(121) linked by a flexible G(4)S tether to the toxin gelonin (rGel) and expressed this as a soluble protein in bacteria. Purified VEGF(121)/rGel migrated as an 84-kDa homodimer under nonreducing conditions. VEGF(121)/rGel bound to purified, immobilized Flk-1, and the binding was competed by VEGF(121). Both VEGF(121)/rGel and VEGF(121) stimulated cellular kinase insert domain receptor (KDR) phosphorylation. The VEGF(121)/rGel fusion construct was highly cytotoxic to endothelial cells overexpressing the KDR/Flk-1 receptor. The IC(50) of the construct on dividing endothelial cells expressing 10(5) or more KDR/Flk-1 receptors per cell was 0.5-1 nM, as compared with 300 nM for rGel itself. Dividing endothelial cells overexpressing KDR were approximately 60-fold more sensitive to VEGF(121)/rGel than were nondividing cells. Endothelial cells overexpressing FLT-1 were not sensitive to the fusion protein. Human melanoma (A-375) or human prostate (PC-3) xenografts treated with the fusion construct demonstrated a reduction in tumor volume to 16% of untreated controls. The fusion construct localized selectively to PC-3 tumor vessels and caused thrombotic damage to tumor vessels with extravasation of red blood cells into the tumor bed. These studies demonstrate the successful use of VEGF(121)/rGel fusion construct for the targeted destruction of tumor vasculature in vivo.     

Test–retest repeatability of [18F]Flortaucipir PET in Alzheimer’s disease and cognitively normal individuals

The aim of this study was to investigate the test–retest (TRT) repeatability of various parametric quantification methods for [¹⁸F]Flortaucipir positron emission tomography (PET). We included eight subjects with dementia or mild cognitive impairment due to Alzheimer’s disease and six cognitively normal subjects. All underwent two 130-min dynamic [¹⁸F]Flortaucipir PET scans within 3 ± 1 weeks. Data were analyzed using reference region models receptor parametric mapping (RPM), simplified reference tissue method 2 (SRTM2) and reference logan (RLogan), as well as standardized uptake value ratios (SUVr, time intervals 40–60, 80–100 and 110–130 min post-injection) with cerebellar gray matter as reference region. We obtained distribution volume ratio or SUVr, first for all brain regions and then in three tau-specific regions-of-interest (ROIs). TRT repeatability (%) was defined as |retest–test|/(average (test + retest)) × 100. For all methods and across ROIs, TRT repeatability ranged from (median (IQR)) 0.84% (0.68–2.15) to 6.84% (2.99–11.50). TRT repeatability was good for all reference methods used, although semi-quantitative models (i.e. SUVr) performed marginally worse than quantitative models, for instance TRT repeatability of RPM: 1.98% (0.78–3.58) vs. SUVr_80–100: 3.05% (1.28–5.52), p < 0.001. Furthermore, for SUVr_80–100 and SUVr_110–130, with higher average SUVr, more variation was observed. In conclusion, while TRT repeatability was good for all models used, quantitative methods performed slightly better than semi-quantitative methods.     

Systematic analysis of research underfunding in maternal and perinatal health

Background  Little published evidence supports the widely held contention that research in pregnancy is underfunded compared with other disease areas.
Objectives  To assess absolute and relative government and charitable funding for maternal and perinatal research in the UK and internationally.
Search strategy, selection criteria, data collection, and analysis  Major research funding bodies and alliances were identified from an Internet search and discussions with opinion leaders/senior investigators. Websites and annual reports were reviewed for details of strategy, research spend, grants awarded, and allocation to maternal and/or perinatal disease using generic and disease-specific search terms.
Main results  Within the imprecision in the data sets, ≤1% of health research spend in the UK was on maternal/perinatal health. Other countries fared better with 1–4% investment, although nonexclusive categorisation may render this an overestimate. In low-resource settings, government funders focused on infectious disease but not maternal and perinatal health despite high relative disease burden, while global philanthropy concentrated on service provision rather than research. Although research expenditure has been deemed as appropriate for 'reproductive health' disease burden in the UK, there are no data on the equity of maternal/perinatal research spend against disease burden, which globally may justify a manyfold increase.
Author's conclusions  This systematic review of research expenditure and priorities from national and international funding bodies suggests relative underinvestment in maternal/perinatal health. Contributing factors include the low political priority given to women's health, the challenging nature of clinical research in pregnancy, and research capacity dearth as a consequence of chronic underinvestment.