Jean-Marie Villette

Mobilization of Visceral Adipose Tissue Related to the Improvement in Insulin Sensitivity in Response to Physical Training in NIDDM: Effects of branched-chain amino acid supplements

OBJECTIVE To evaluate the effects of an intense physical training program on abdominal fat distribution, glycemic control, and insulin sensitivity in patients with NIDDM and to determine whether branched-chain amino acid (BCAA) supplements influence these effects. RESEARCH DESIGN AND METHODS Twenty-four patients (ages 45 ± 2 [mean ± SE] years, BMI 30.2 ± 0.9 kg/m2, HbA1c 7.9 ± 0.3%) were randomly assigned to four groups: training plus BCAA supplement (n = 6), training plus placebo (n = 6), sedentary plus BCAA supplement (n = 6), and sedentary plus placebo (n = 6). Physical training consisted of a supervised 45-min cycling exercise at 75% of their oxygen uptake peak (VO2 peak) two times per week and an intermittent exercise one time per week for 2 months. RESULTS Patients who exercised increased their VO2 peak by 41% and their insulin sensitivity by 46%. Physical training significantly decreased abdominal fat evaluated by magnetic resonance imaging (umbilicus), with a greater loss of visceral adipose tissue (VAT) (48%) in comparison with the loss of subcutaneous adipose tissue (18%), but did not significantly affect body weight. The change in visceral abdominal fat was associated with the improvement in insulin sensitivity (r = 0.84, P = 0.001). BCAA supplementation had no effect on abdominal fat and glucose metabolism. CONCLUSIONS Physical training resulted in an improvement in insulin sensitivity with concomitant loss of VAT and should be included in the treatment program for patients with NIDDM.

Simultaneous radioimmunoassay of progesterone, androst-4-enedione, pregnenolone, dehydroepiandrosterone and 17-hydroxyprogesterone in specific regions of human brain.

Simultaneous determination of progesterone, androst-4-enedione, pregnenolone, dehydroepiandrosterone (DHEA) and 17-hydroxyprogesterone has been developed for human cerebral tissue. Before immunoassay, steroids were separated on a Celite column with propylene glycol as stationary phase with hexane containing increasing proportions of dichloromethane as mobile phase. This system allowed separation of steroids of similar polarity, especially of pregnenolone and progesterone. The brain regions studied cortex (prefrontal, parietal and temporal), cerebellum and corpus callosum, were obtained after autopsy from 9 women and 1 man between 76 and 93 years of age. Steroids were found in all regions. The overall concentrations expressed in nmol/kg of tissue were: 10.1, 7.6, 120.7, 19.6 and 10.4 respectively, for progesterone, androst-4-enedione, pregnenolone, dehydroepiandrosterone and 17-hydroxyprogesterone, corresponding to 7.3, 4.9, 74, 6.5 and 9.2 times the plasma levels. These very high concentrations, not previously described in human brain tissue, pose the question of the existence of local biosynthetic pathways independent of the peripheral endocrine gland system as well as that of progressive accumulation of steroids over a lifetime. Concentrations of each steroid in each subject varied little among the various brain regions studied, but there was much variation among the subjects with respect to the concentrations of a given steroid.

Plasma neuroendocrine markers in patients with benign prostatic hyperplasia and prostatic carcinoma

PURPOSE Approximately 50% of all malignant prostatic tumors contain neuroendocrine cells, which cannot be attributed to small cell prostatic carcinoma or carcinoid-like tumors, and which represent only 1 to 2% of all prostatic malignancies. Only limited data are available concerning the plasma levels of neuroendocrine markers in patients with prostatic tumors. Therefore, we determine the incidence of high plasma levels of neuroendocrine markers in patients with benign and malignant prostatic disease. MATERIALS AND METHODS The presence of elevated plasma neuropeptide levels was investigated in 135 patients with prostatic carcinoma and 28 with benign prostatic hyperplasia. Plasma chromogranin A, neurone-specific enolase, substance P, calcitonin, somatostatin, neurotensin and bombesin levels were analyzed by immunoassays, and were compared to clinical and pathological stages of disease. Plasma prostatic acid phosphatase and prostate specific antigen levels were also determined. All patients were followed for at least 2 years after inclusion in the study. RESULTS Significantly elevated levels of chromogranin A were detected in 15% of patients with prostatic carcinoma before any treatment. During hormone resistant prostate cancer progression plasma chromogranin A and neuron-specific enolase levels were elevated in 55% and 30% of the patients, respectively. In patients with stage D3 disease survival curves were generated by the Kaplan-Meier method, and log rank analysis revealed a statistically significant difference between groups positive and negative for chromogranin A. Substance P and bombesin were also occasionally elevated in prostatic tumors. Determination of neuroendocrine differentiation by neuron-specific enolase or chromogranin A immunoassays was not helpful in the prediction of progressive localized prostatic carcinoma. CONCLUSIONS Future studies of plasma neuropeptide levels should confirm whether these parameters can be used as prognostic markers during late progression of prostatic carcinoma or for the selection of patients suitable for evaluation of new antineoplastic drugs to be active against neuroendocrine tumors.

Prostate epithelial cell lines form spheroids with evidence of glandular differentiation in three-dimensional Matrigel cultures

Normal (PNT2-C2) and metastatic (PC-3) prostate cell lines were grown in Matrigel to observe the effects on morphology and phenotype in comparison to monolayer culture. In monolayer cultures, PNT2-C2 showed typical round/cuboidal epithelial morphology, with tight cell associations, whereas in Matrigel they formed smooth spheroids, tightly packed with cells. In both monolayer and Matrigel, PNT2-C2 had a differentiated luminal epithelial phenotype with high expression of cytokeratin 8, prostate specific antigen (PSA), prostate specific membrane antigen (PSMA), E-cadherin and desmoglein. In contrast, PC-3 cells possessed an epithelial/mesenchyme morphology in monolayer with loose cell to cell contact and pseudopodial extensions. Immunohistochemical phenotyping indicated the cells were undifferentiated, expressing high levels of vimentin, β1 integrin, CD44 and low expression of cytokeratin 8. In Matrigel they formed smooth and irregular spheroids, which had a lumen surrounded by a single cell layer. Matrigel also influenced the expression of PSA, PSMA and CD44. These results indicate that Matrigel culture can induce morphological differentiation of prostate cancer cells which initially had a basal phenotype.

Evaluation and clinical value of neuroendocrine differentiation in human prostatic tumors

Prostate cancer, like other solid tumors, is a rather heterogeneous entity. More than 50% of all malignant prostatic tumors contain neuroendocrine‐like cells, which cannot be attributed to small cell prostatic carcinoma or carcinoid‐like tumors, which represent only 1–2% of all prostatic malignancies. Several investigators have reported that histopathologic determination of neuroendocrine differentiation in prostate carcinomas may have prognostic implications, while others have not confirmed these results. However, on the basis of experimental data, neuroendocrine‐like cells appear to be involved in the emergence of androgen‐independent cells and could be a target for new prostate cancer therapeutic strategies.

UPREGULATION OF ENDOTHELIN 1 AND ITS PRECURSOR BY IL-1β, TNF-α, and TGF-β IN THE PC3 HUMAN PROSTATE CANCER CELL LINE

Abstract Increasing evidence indicates that endothelin 1 (ET-1) is implicated in prostate tumour progression. However, data on ET-1 regulation in human prostate and prostate cancer cell lines are lacking. In this study, regulation of ET-1 and its precursor big ET-1, using PC3 cells, a human bone metastatic prostatic carcinoma cell line, was addressed. ET-1 and big ET-1 assays demonstrated greater secretion of both peptides in the presence of 10% fetal calf serum (FCS) as compared with 0.5% FCS. Incubation of PC3 cells in the absence and presence of various cytokines and growth factors known to be implicated in prostate stroma-epithelium interactions, revealed that IL-6, FGF7/KGF and FGF2/bFGF had no effect on ET-1 and big ET-1 secretion, whereas interleukin 1β (IL-1β), tumour necrosis factor α (TNF-α) and transforming growth factor β (TGF-β) stimulated their secretion in a concentration-dependent manner. Binding experiments indicated the presence of specific ET-1 receptors in PC3 cells: K d app =1.1×0.2×10 −10 M, B max =2660±390 sites/cell. Data analysis demonstrated the presence of only the ETA receptor subtype in PC3 cells. In conclusion, our results indicate that the implication of ET-1 in prostate cancer is likely to be mediated via paracrine/autocrine control of cell factors.

Androgens are not a direct requirement for the proliferation of human prostatic epithelium in vitro

The androgen receptor pathway is known to be a key regulator of growth in the normal and pathological prostate. However, the precise mechanisms of this signaling pathway with respect to the different cellular compartments of the prostate remain largely unknown. We have used a primary culture system to grow human prostatic epithelial cells of normal, benign, tumor and metastatic origin, as well as immortalized human prostatic epithelial cell lines, to demonstrate the absence of a direct or indirect effect of androgens on cellular proliferation in vitro. In parallel to this observed androgen independence for growth, all cell systems lost significant expression of androgen receptor, prostate‐specific antigen and prostatic acid phosphatase. Since the androgen receptor is expressed in the epithelium in situ, our results suggest that the androgen effect on epithelial cells may be one of prostatic differentiation rather than proliferation, and that the androgen receptor/growth factor pathway acts through mesenchymal‐epithelial interactions. Int. J. Cancer 73:910–916, 1997.

Telomerase activity as a potential marker in preneoplastic bladder lesions

Objective To assess telomerase activity (involved in cell immortalization and detectable in most malignant tumours but not in normal somatic tissues) as a marker in cancer diagnosis.

In vivo model mimicking natural history of dog prostate cancer using DPC-1, a new canine prostate carcinoma cell line

Dog prostate cancer is usually considered to be highly relevant to human prostate cancer. We report the isolation of a new canine prostate cancer epithelial cell line designated DPC‐1.

FGF7/KGF triggers cell transformation and invasion on immortalised human prostatic epithelial PNT1A cells

Fibroblast growth factor 7 (FGF7/KGF) is synthesized exclusively by fibroblasts in normal tissues; it acts as a potent mitogen on epithelial cells, through interaction with the FGF7‐specific receptor FGFR2/IIIb. To examine the importance of this growth factor both to prostate physiology and to prostate‐cancer progression, we have tested the exogenous effect of FGF7. Thus, by mimicking the paracrine pathway (on proliferation, growth in soft agar and invasion) on the human prostatic epithelial cell line PNT1A positively checked for FGFR2/IIIb expression, FGF7 significantly enhanced cell proliferation at an optimal concentration of 7.5 × 10−11 M, but no significant invasion or growth in soft agar were observed. To confirm FGF7 properties on human prostatic epithelial cells, we constitutively expressed FGF7 by transfecting PNT1A cells with FGF7‐cDNA. The FGF7‐transfected clones, PNT1A/FGF7‐T5 and PNT1A/FGF7‐T6, were stable and expressed FGF7. Analysis of the FGF7‐autocrine loop on the non‐tumorigenic epithelial cells PNT1A showed acquired invasive potential in in vitro extracellular‐matrix migration assays, specifically inhibited by an FGF7‐neutralizing antibody, and over‐expressed factors implicated in the migration process: the metalloproteinase MMP‐1 and the plasminogen activator uPA. Taken together, these results demonstrate a role for FGF7 in triggering invasion of human prostatic epithelial cells. Furthermore, these FGF7‐transfected clones exhibited functional and physiological differences from the original PNT1A cell line: anchorage‐independent growth, growth in serum‐free media and increased proliferation. These data confirm the oncogenic function of FGF7 in prostate progression potentially acting through paracrine and/or autocrine regulatory pathways. Int. J. Cancer 82:237–243, 1999.