Absence of correlation between BMP-4 polymorphism and postmenopausal osteoporosis in Italian women

Several studies have demonstrated that bone has the power of regeneration and repair. BMPs (bone morphogenetic proteins) are involved in the determination of osteoblast phenotype and bone turnover, therefore genes coding for these proteins, like BMP-4, could be considered potential candidate genes for osteoporosis. We investigated the association of BMP-4 gene polymorphism with osteoporosis in a cohort of 72 osteoporotic, postmenopausal women and 82 unrelated controls. We failed to detect any significant association between this genetic marker and the disease.

Corticosteroid-induced osteoporosis: pathogenesis and prevention

In spite of their adverse side effects, natural and synthetic glucocorticoids (GCs) occupy a unique role in several fields of medicine. They are potent regulators of bone cell growth and differentiation and the actions on the skeleton and related tissues depend on several factors including the dose, duration of the exposure, the steroid type and the species. In humans some of the effects are indirect, such as the regulation of intestinal calcium absorption and PTH secretion. Other effects are due to the cellular response that occurs within the bone microenvironment. It has been well established in in vitro studies that GCs can promote osteoblast differentiation from mesenchymal osteoprogenitors both in rat calvarial culture and in adherent marrow stromal cells. Moreover, GCs are able to enhance expression of the mature osteoblast phenotype, increasing mineralized nodules, osteocalcin secretion, and the bone morphogenetic protein-6 message level. However, the mechanisms by which GCs affect bone metabolism are still unclear. Recent studies with GCs on bone cells suggested that the production of cytokines and growth factors and the expression of their receptors may also be influenced by GCs. In fact, GCs are able to inhibit the synthesis of cytokines, such as interleukin-1 which stimulates bone remodeling by monocytes and macrophages. Moreover, osteoprotegerin, a recently cloned member of the tumor necrosis factor receptor family, is down-regulated by GCs, offering a possible interpretation for the induction of bone resorption by GCs. GC-induced inhibition of bone resorbing cytokines may contribute to explain the therapeutic actions of GCs in several diseases such as rheumatoid arthritis and myeloma. Furthermore, GCs modulate osteoclast recruitment, even if there is no clear explanation for a direct effect of GCs on osteoclastic precursors. Sustained stimulation of matrix degradation by isolated avian osteoclasts incubated with GCs has been reported, as well as cytotoxic effects on osteoclastic cells from neonatal rat long bones.

Cardiovascular effects of parathyroid hormone: a study in healthy subjects and normotensive patients with mild primary hyperparathyroidism

The aim of the study was to evaluate: 1) the cardiovascular function and the autonomic drive to the heart in patients affected by primary hyperparathyroidism (pHPT) with no evidence of renal and cardiovascular complications; 2) the cardiovascular effects of acute administration of PTH in normal subjects. In 14 patients affected by mild asymptomatic pHPT echocardiographic assessment of cardiovascular function and of the mechanic properties of the brachial and carotid artery, heart rate variability and the dispersion of QT interval were performed before and 6 months after successful surgery. Twenty age- and sex-matched healthy subjects were included in the study. Five healthy volunteers underwent a single blind, placebo-controlled, random order, cross-over study with infusion of PTH (hPTH 1-34, 200 U in saline over 5 min) or placebo. Echocardiographic assessment of cardiovascular function, heart rate variability, and QT interval were performed between 20 and 25 min after the start of the infusion and repeated after 15 min of tilting at 60 degrees. In pHPT patients the echocardiographic parameters were normal; left ventricular isovolumetric relaxation time was always in the normal range, but significantly shorter than in control subjects, suggesting an increased sympathetic stimulation. Arterial diameters and thickness, blood pressure, and QT interval were not significantly different with respect to normal subjects and were unchanged 6 months after surgery. pHPT patients lacked the circadian rhythm of the low frequency to high frequency ratio, suggesting an increased sympathetic drive to the heart at nighttime. In normal subjects there were no significant differences in basal echocardiographic measurements during PTH infusion with respect to placebo and in the hemodynamic response to tilt. These results suggest that cardiovascular function is substantially normal in normotensive pHPT patients with mild hypercalcemia. A modulation of the adrenergic control of circulation seems to be associated with hypercalcemia and/or chronic PTH excess, but its biological relevance needs further investigations.

Intraoperative parathormone measurement in patients with multiple endocrine neoplasia type I syndrome and hyperparathyroidism

Total or subtotal parathyroidectomy is considered the treatment of choice for multiple endocrine neoplasia type I (MEN-I)-associated primary hyperparathyroidism (HPT). However, persistent or recurrent HPT is frequently observed. The development of a rapid two-site immunoradiometric assay (IRMA) method for measuring intact parathormone (PTH) has provided a valuable tool for recognizing possible surgical failures. Our experience includes 16 MEN-I patients (10 females, 6 males) of mean age 35.5 years operated on between 1990 and 1996. Total parathyroidectomy (TPTX) with autotransplantation of parathyroid tissue was the standard treatment. Blood samples for PTH measurement were drawn at the induction of anesthesia (basal value), 10 and 20 minutes after the removal of each gland, and 60 minutes after TPTX. Rapid PTH measurement, which required only 15 minutes of incubation at 37 degrees C, showed a highly significant correlation (p < 0.0001) with the standard method. Circulating PTH levels exhibited a stepwise decrease during TPTX, reaching a mean value of 22.3% of the baseline 20 minutes after removal of the last gland. Two patients showed a prompt decrease of PTH after removal of the single enlarged gland, featuring the kinetics observed in the adenomas. One of these two patients was successfully treated with more conservative surgery. None of the patients showed persistence or recurrence of HPT. In our experience, intraoperative measurement of PTH seems to be a valuable adjunct in both the diagnosis of multiglandular involvement and the prediction of surgical treatment in patients with primary parathyroid hyperplasia.

Discriminant capacity of quantitative ultrasound versus dual X-ray absorptiometry to determine cancellous bone loss in ovariectomized rats

The capacity of dual x-ray absorptiometry and quantitative ultrasound to discriminate bone loss and to predict the mechanical and microarchitectural properties of cancellous bone in an animal model of osteopenia was evaluated. Thirty-five female Sprague-Dawley rats (10 months old) were randomized into three groups: baseline group, 10 rats killed at the beginning of the study; ovx group, 15 rats ovariectomized; and sham group, 10 rats sham operated. At the beginning and end of the study, all the animals underwent osteosonography to record the proximal tail (C3 vertebra) bone speed of sound. Sixteen weeks after surgery, the animals were euthanized and the L5-6 lumbar vertebrae of each rat were excised for densitometric, biomechanical (compression test), and histomorphometric studies. Significant differences were found among the groups for final speed of sound (p = 0.01). The L5 bone mineral density of the ovx group decreased by 12.1% (p = 0.049) and 12.6% (p = 0.035) compared, respectively, with baseline and sham groups. The biomechanical parameters of the ovx group decreased by 15-47% compared with the other groups, showing significant differences between the ovx and sham groups both for maximal stress (p = 0.026) and elastic modulus (p = 0.013). Histomorphometric parameters of the ovx group showed significant decreases in comparison with other groups. Logistic regression analysis showed that dual X-ray absorptiometry and quantitative ultrasound discriminate ovariectomized and healthy rats with a similar capacity, classifying correctly all rats used in the model in a range of 61-70%. This similar capacity seems to derive from two different capacities to detect bone changes. Dual X-ray absorptiometry, depending on bone mineralization and density, is able to detect modifications in bone stiffness and strength, confirmed also by the correlation with biomechanical data. On the contrary, quantitative ultrasound seems to depend more on cancellous bone microarchitecural changes because it is correlated to histomorphometric parameters.

MEN1 gene mutation analysis in Italian patients with multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN 1) is a familial syndrome characterized by parathyroid, enteropancreatic and pituitary tumors. The gene responsible for this syndrome is localized at chromosomal 11q13 region and DNA markers from this region cosegregate with the disease. The recent identification of the MEN1 gene, encoding for a protein termed menin of 610 amino acids, allowed mutational screening to be performed both in affected families and sporadic cases. To date many different heterozygous mutations, spreading across all the encoding sequence, have been identified in MEN 1 patients with no apparent mutational hot spots or genotype-phenotype correlation. To analyze the genetic alterations of the MEN1 gene occurring in Italian patients we performed mutational screening by Denaturant Gradient Gel Electrophoresis followed by sequencing of exons 2-10 of the MEN1 gene in 27 Italian MEN 1 families and in five sporadic cases. We identified 17 different heterozygous mutations in 60% of analyzed cases. Twelve of these mutations are novel. Two mutations each occurred twice in unrelated families but no evidence of genotype-phenotype correlation can be established for these families. The extension of genetic diagnosis to asymptomatic family members allowed the identification of 10 MEN1 mutant gene carriers, one newly described and nine previously detected by linkage analysis with DNA markers from the 11q13 region. Our findings add new information to the diversity of mutations occurring in the MEN1 gene and confirm that the mutational screening of MEN 1 is a useful approach to detect individuals at higher risk of developing MEN 1-associated tumors.

Vitamin D receptor as a candidate tumor-suppressor gene in severe hyperparathyroidism of uremia

Most chronic renal failure patients with severe refractory hyperparathyroidism harbor at least one monoclonal parathyroid tumor, but the specific acquired genetic defects that confer this clonal selective advantage remain poorly understood. Somatic inactivation of the vitamin D receptor (VDR) gene could contribute to clonal outgrowth, because a parathyroid cell containing this lesion would have an impaired response to the antiproliferative influence of 1,25-dihydroxyvitamin D3. Furthermore, diminished expression of VDR protein has been described in uremia-associated parathyroid tumors. Therefore, to assess VDR gene inactivation's potential pathogenetic role in this disease, we rigorously analyzed the VDR gene in 59 parathyroid tumors surgically resected from uremic patients. First, Southern blotting and/or PCR analyses of 29 tumor samples from 14 genetically informative patients revealed no allelic losses at the VDR locus. Next, direct DNA sequencing of all VDR splice junctions, associated intronic sequences, and virtually the entire VDR-coding region for all 59 tumors revealed no acquired mutations. Last, 37 tumor DNA samples were subjected to comparative genomic hybridization, and no chromosomal losses in the VDR region (12cen-q12) were observed. These observations suggest that inactivating defects within the VDR gene do not commonly contribute to the primary pathogenesis of severe refractory hyperparathyroidism in uremia.

Parathyroid glands: combination of (99m)Tc MIBI scintigraphy and US for demonstration of parathyroid glands and nodules

PURPOSE

To determine the appropriate choice of imaging techniques for localization of nodular lesions of parathyroid glands.

MATERIALS AND METHODS

First, computed tomographic (CT), magnetic resonance (MR), ultrasonographic (US), and technetium 99m methoxyisobutyl-isonitrile (MIBI) scintigraphic images in 49 patients with primary hyperparathyroidism were retrospectively evaluated. A single-blind, prospective study that included 16 patients with primary hyperparathyroidism was then conducted. MR, US, scintigraphic, and color Doppler US images of the neck were obtained and analyzed.

RESULTS

In the retrospective study, CT, MR imaging, and US had low sensitivity (13%, 17%, and 27%, respectively) and specificity (39%, 65%, and 65%, respectively). Scintigraphy had 57% sensitivity and 85% specificity. In the prospective study, the use of latest-generation MR and US equipment and the participation of experienced operators led to improved sensitivity and specificity for these techniques. The combination of US and scintigraphy resulted in improved sensitivity (96%), specificity (83%), and positive and negative predictive values (88% and 94%, respectively), relative to the results obtained with either method alone. Doppler US was of little help in the setting of small glands.

CONCLUSIONS

The combination of (99m)Tc MIBI scintigraphy and US performed by well-trained operators with up-to-date instruments appeared to be the best diagnostic tool for the preoperative diagnosis of parathyroid disease.

In vitro expression of proalpha1(I) collagen mRNA by human pre-osteoclastic cells

In vitro studies have demonstrated that the extracellular matrix modulates the cell phenotype. In the present study we have investigated in vitro proalpha1(I) collagen mRNA expression in a human pre-osteoclastic cell line (FLG 29.1 cells) in basal condition and after various stimuli. In addition, in order to evaluate the effect of cell-cell interactions on collagen type I mRNA expression, we have cultured the human pre-osteoclastic cells FLG 29.1 with either the human osteoblast-like cell line Saos-2 or the bovine bone endothelial cell line BBE. We showed that the FLG 29.1 cells express proal (I) collagen mRNA, whose expression is modulated by phorbol esters (TPA). Co-culturing FLG 29.1 cells with either Saos-2 or BBE cells induced decrease of proalpha1(I) collagen mRNA expression.

Randomized trial of the effects of risedronate on vertebral fractures in women with established postmenopausal osteoporosis. Vertebral Efficacy with Risedronate Therapy (VERT) Study Group

The purpose of this randomized, double-masked, placebo-controlled study was to determine the efficacy and safety of risedronate in the prevention of vertebral fractures in postmenopausal women with established osteoporosis. The study was conducted at 80 study centers in Europe and Australia. Postmenopausal women (n = 1226) with two or more prevalent vertebral fractures received risedronate 2.5 or 5 mg/day or placebo; all subjects also received elemental calcium 1000 mg/day, and up to 500 IU/day vitamin D if baseline levels were low. The study duration was 3 years; however, the 2.5 mg group was discontinued by protocol amendment after 2 years. Lateral spinal radiographs were taken annually for assessment of vertebral fractures, and bone mineral density was measured by dual-energy X-ray absorptiometry at 6-month intervals. Risedronate 5 mg reduced the risk of new vertebral fractures by 49% over 3 years compared with control (p<0.001). A significant reduction of 61% was seen within the first year (p = 0.001). The fracture reduction with risedronate 2.5 mg was similar to that in the 5 mg group over 2 years. The risk of nonvertebral fractures was reduced by 33% compared with control over 3 years (p = 0.06). Risedronate significantly increased bone mineral density at the spine and hip within 6 months. The adverse-event profile of risedronate, including gastrointestinal adverse events, was similar to that of control. Risedronate 5 mg provides effective and well-tolerated therapy for severe postmenopausal osteoporosis, reducing the incidence of vertebral fractures and improving bone density in women with established disease.

Estrogen synthesis in human colon cancer epithelial cells

Epidemiological and experimental data suggest an involvement of estrogen in the development and progression of colorectal cancer. In order to determine whether local synthesis of estrogen occurred in human colonic cancer cells, two colorectal cancer cell lines, HCT8 and HCT116, were evaluated for gene expression and enzyme activity of cytochrome P450 aromatase. In addition, the effect on aromatase expression of charcoal-stripped fetal calf serum, of quercetin and genistein and of tamoxifen and raloxifene was investigated in both cell lines. RT-PCR analysis revealed that colorectal adenocarcinoma cell lines contain aromatase as a major component. The conversion of [(3)H]-androstenedione to estrone and labeled water was dose-dependently inhibited by 4-hydroxyandrostenedione and obeyed Michaelis-Menten kinetic with apparent Km values of approximately 20 nM and V(max) values of approx. 200 and 500 fmol/mg protein/h for HCT8 and HCT116 cells, respectively. After 24 h incubation, genistein (1 microM) significantly increased aromatase activity in HCT8 cells, with no effect on HCT116 cells. In accord with previous observation in reproductive tissues, quercetin (1 microM) significantly inhibited the enzyme activity in both cell lines. Also tamoxifen (100 nM) acted as inhibitor, while raloxifene (10 nM) decreased the enzyme activity only in HCT116 cells. The aromatase gene expression modulation by these effective agents was consistent with their effects on enzyme activity. These findings demonstrate for the first time that colorectal adenocarcinoma cell lines express aromatase. Interestingly, the enzyme activity was inhibited by quercetin, one major dietary flavonoid, by tamoxifen, a hormonal therapeutic agent for breast cancer, and by raloxifene, used in the prevention of postmenopausal osteoporosis.

Fluid shear stress increases interleukin-11 expression in human osteoblast-like cells: its role in osteoclast induction

It is unclear how mechanical stress influences bone cells. Mechanical stress causes fluid shear stress (FSS) in the bone. Osteoblast lineage cells are thought to sense FSS and regulate bone remodeling. We therefore investigated the effects of FSS on human osteoblast-like osteosarcoma cells: SaOS-2 cells in vitro. The conditioned medium of the SaOS-2 cells after 24 h of FSS (24 h-FSS CM) showed such osteoclastic phenotype inductions as significantly increasing the number of tartrate-resistant acid phosphatase (TRAP) positive multinuclear cells in rat bone marrow cells and TRAP-positive cells in human preosteoclastic cells: FLG 29.1 cells. An enzyme-linked immunosorbent assay showed interleukin-11 (IL-11) protein to increase 7-fold in the 24 h-FSS CM. A Northern analysis showed that IL-11 mRNA increased 4-fold in the SaOS-2 cells after 6 h-FSS; however, no IL-6 mRNA expression was detected. Furthermore, the anti-human IL-11 antibody significantly neutralized the osteoclastic phenotype induction of the 24 h-FSS CM. The IL-11 mRNA up-regulation in SaOS-2 cells by the 6 h-FSS was not inhibited by the anti-human transforming growth factor-beta1 antibody, but it was significantly inhibited by indomethacin. An enzymeimmunoassay showed prostaglandin E2 to increase 7-fold in the 1 h-FSS CM. These findings thus suggest that FSS induces osteoblasts to produce IL-11 (mediated by prostaglandins) and thus stimulates bone remodeling.

Association of the estrogen receptor alpha gene polymorphisms with sporadic Alzheimer's disease

Alzheimer's disease (AD) is a multifactorial disorder determined by the interaction of genetic, metabolic, and environmental factors. In the common late-onset familial and sporadic forms of AD apolipoprotein E type 4 allele (APOE-epsilon4) is now widely accepted as a major risk factor. The association of estrogen treatment with a reduction in the risk of AD together with the modulation by estrogen of the secretory metabolism of the amyloid precursor protein offers new possibilities for identification of other AD susceptibility genes, as those encoding for the estrogen receptors (ERs). A total of 193 patients with sporadic late-onset AD, meeting the NINCDS-ADRDA criteria, and a total of 202 control subjects, age and education matched, were included in this study. PvuII and XbaI ERalpha and HhaI APOE gene polymorphisms were evaluated in genomic DNA by Polymerase Chain Reaction (PCR). The frequency of the various ERalpha genotypes by the combination of P, p and X, x was calculated for controls and AD patients stratified based on ApoE typing. When the two ERalpha gene polymorphisms were analyzed in combination, 7 genotypes were recognized, with a significantly increased prevalence of PPXX genotype in AD patients compared to controls (P = 0.0001). Risk of AD increased by a factor of 7.6 (CI [1.10-62.3]) in homozygous APOE-epsilon4 individuals with PPXX ERalpha genotype. These results are consistent with a segregation of PPXX ERalpha genotype with a higher risk of developing late-onset sporadic AD in the Italian population. The ERalpha gene appears to interact with the APOE-epsilon4 genotype in determining AD susceptibility.

Telomerase repeat amplification protocol (TRAP): A new molecular marker for parathyroid carcinoma

Telomerase results to be active in human germ, stem cells, several malignant cell tumors and in immortalized cell lines. In order to investigate if molecular mechanisms other than Rb gene inactivation can be helpful to diagnose malignancy of parathyroid tumors, we decided to investigate the presence of active telomerase in homogenates from different pathological parathyroid tissues (hyperplastic, adenomatous, carcinomatous, and normal) and primary cell cultures. The TRAP assay was performed to detect this activity in histologically characterized normal, hyperplastic, adenomatous, and carcinomatous human parathyroid tissues, primary cell lines, and one metastatic tissue from parathyroid carcinoma. Only malignant parathyroid glands and the metastatic tissue were TRAP positive. Our findings suggest that telomerase expression could represent an important molecular mechanism underlying the acquisition and progression of an aggressive phenotype of epithelial parathyroid cells and it may help to predict their malignant potential. The TRAP assay is easy to perform and it could become an additional tool to be included in the harmamentarium for the molecular diagnosis of parathyroid carcinoma.

Functional estrogen receptor beta in colon cancer cells

Evidence exists for expression of estrogen receptor beta (ERbeta) in human colonic mucosa. Here we investigated the expression of the classical ER (ERalpha) and of four isoforms of the human ERbeta in HCT116, HCT8, DLD-1, and LoVo colon adenocarcinoma cell lines. In addition, [(3)H]17beta-estradiol (17betaE(2)) binding to intact colon cancer cells was evaluated. RT-PCR and Western blot analyses showed lack of expression of the classical ERalpha in the four colon cancer cell lines. Conversely, wild-type ERbeta isoform 1 was highly expressed in HCT8, HCT116, DLD-1, and LoVo cells and isoforms ERbeta2-5 were present in HCT8 and HCT116 cells. Scatchard and Hill analysis of [(3)H]17betaE(2) binding to the four different colon cancer cells revealed the presence of two classes of binding sites, one with high affinity (K(d) values of 1-2 nM) and the other with lower affinity (K(d) values of 10-20 nM). Forty-eight hour-pretreatment of cells with 1 and 10 nM 17betaE(2) did not induce an increase of progesterone-specific binding to HCT8 cells, while a significant induction was observed after treatment with 10 nM 17betaE(2) in HCT116 and DLD-1 cells and with both concentrations in LoVo cells. In addition, 1 pM-0.1 nM 17betaE(2) significantly induced cell proliferation of HCT8 cells, while reducing growth of HCT116 and DLD1 cells at 10 nM-1 microM concentrations and of LoVo cells at all tested concentrations (1 pM-1 microM). These in vitro findings pose the basis for in vivo functions of ERbeta and ERbeta-interacting molecules in human colon cancer tissue.

FokI polymorphism at translation initiation site of the vitamin D receptor gene predicts bone mineral density and vertebral fractures in postmenopausal Italian women

A novel T/C polymorphism (ATG to ACG) at the translation initiation site of the vitamin D receptor (VDR) gene, defined by FokI restriction endonuclease, has been recently associated with variation in bone mineral density (BMD) and rates of bone loss in a group of postmenopausal Mexican-American women. The presence of the restriction site, designated as f, allows protein translation to initiate from the first ATG, while the allele lacking the site, indicated as F, initiates translation at a second ATG. In this study, we investigated the role of FokI polymorphism in a group of 400 postmenopausal women of Italian descent stratified for BMD into osteoporotic (n = 164), osteopenic (n = 117), and normal (n = 119) groups. There were 159 (41%) FF homozygotes, 55 (14%) ff homozygotes, and 186 (45%) Ff heterozygotes. In the whole population, we observed a weak association between FokI polymorphism and lumbar BMD (p = 0.06, analysis of covariance [ANCOVA]) but not with femoral neck BMD (p = 0.5, ANCOVA). Interestingly, the effect of FokI genotypes on lumbar BMD was influenced by the years since menopause such that differences in BMD related to different VDR allelic variants were greater among women in the first 5 years of menopause (p = 0.04, ANCOVA), progressively declining afterward. In addition, a significantly higher prevalence of ff genotype in osteoporotic than in osteopenic and normal women was observed (p = 0.04, Chi-square test). Finally, ff genotype resulted significantly over-represented in the group of women with a vertebral fracture as compared with controls (p = 0.003, Chi-square test), equivalent to a relative risk of 2.58 (95% confidence intervals 1.36-4.91). We conclude that in this population, FokI polymorphism at the VDR gene locus accounts for a part of the heritable component of BMD at the lumbar spine.

17beta-estradiol induces apoptosis in the preosteoclastic FLG 29.1 cell line

Although compelling data have demonstrated the effectiveness of estrogen replacement therapy for the treatment of accelerated bone loss in postmenopausal osteoporosis and ovariectomized animals, the mechanisms by which estrogens reduce bone resorption remain to be elucidated. To address this issue, in the present study we investigated whether estrogens were able to induce programmed cell death or apoptosis in osteoclast precursors. To this purpose, a preosteoclastic cell line (FLG 29.1) was cultured in the absence or presence of nanomolar concentrations of 17beta-estradiol (17betaE2). Using time-lapse videomicroscopy, it was shown that 17betaE2 induced FLG 29.1 cell apoptosis in a dose- and time-dependent manner. Furthermore, a significant increase in the activity of caspase 3 enzyme and in the number of nuclei undergoing DNA fragmentation was observed in FLG 29.1 cells treated with 17betaE2 compared to untreated cells. Finally, transmission electron microscopy of the treated cells showed typical apoptotic morphology. These data indicate that 17betaE2 is able to promote in vitro apoptosis in preosteoclastic cells and suggest that estrogenic molecules may exert in vivo a direct role in negatively modulating the pool of undifferentiated bone marrow cells capable ultimately of maturing into osteoclasts.

Expression of Src family kinases and their putative substrates in the human preosteoclastic cell line FLG 29.1

Several lines of evidence suggest that the c-Src tyrosine kinase has a specific role in bone-resorbing osteoclasts. To investigate this further, we examined the expression of c-Src, its kinase family members, and their putative substrates in the human leukemia cell line FLG 29.1. Western blot analysis with specific antibodies against Src family members showed expression of Src, Fyn, and Lyn, lower levels of Yes and Hck, and the absence of Lck tyrosine kinase. During a 3-day treatment with phorbol 12-myristate, 13-acetate (PMA), which induces differentiation of FLG 29.1 cells toward an osteoclast-like phenotype, the levels of Src and Fyn increased and the levels of Lyn decreased. In a similar leukemia cell line, HL-60, Src protein was not constitutively expressed and not induced by PMA treatment, which leads to monocytic differentiation. PMA treatment of FLG 29.1 cells induced a strong increase in the expression of p120 Cbl and Pyk2 kinase, which are putative Src substrates. Pyk2 phosphorylation increased upon adherence of FLG 29.1 cells to fibronectin and to ST2 stromal cells. The expression of other Src substrates and interacting proteins, such as p120 Cas, p130 Cas, vinculin, Fak kinase, and the p85 phosphatidylinositol 3-kinase subunit either did not change or slightly increased during PMA treatment. The elevated total protein tyrosine phosphorylation in PMA-treated FLG 29.1 cells was abolished by herbimycin A, a Src inhibitor. These data are consistent with the proposed role of Src in the osteoclastic function and support the use of FLG 29.1 cells as a model to study Src substrates in the cells of the osteoclastic lineage.

Apoptosis induced by sulindac sulfide in epithelial and mesenchymal cells from human abdominal neoplasms

We investigated whether the therapeutic action of sulindac, used for the treatment of familial adenomatous polyposis, desmoid tumors, and against colon cancer, could be mediated by its active metabolite, sulindac sulfide, in cell growth and apoptosis on cell lines derived from abdominal neoplasms. Sulindac sulfide actions on cell growth and apoptosis were evaluated in epithelial human colon tumor 8 (HCT8) cell line and mesenchymal cell lines (bovine bone endothelial (BBE) cell line, desmoid tumor-derived cells, human colorectal cancer-derived fibroblasts). Sulindac sulfide (0.1-60 microg/ml) induced a dose-dependent inhibition of cell proliferation of all cell lines tested. Apoptosis was induced at doses of 20 and 40 microg/ml, respectively, in BBE and HCT8 cells with no effect on desmoid tumor cells and colorectal cancer-derived fibroblasts. Since mesenchymal cells respond to clinically effective concentrations of the compound, its preferential action on the stromal compartment of intestinal polyps, desmoid tumors and colon cancer can be proposed, with consequent regression of the tumor.

Effects of ipriflavone on perialveolar bone formation

The effect of ipriflavone (IP), a synthetic isoflavonoid derivative, on in vivo bone formation was studied in rat perialveolar bone by surgically producing a hole in the mandibular bone. The holes were filled either with powdered IP or with compounds containing no osteoinductive properties such as biostite and Htr (hard tissue replacement). In control animals, the holes were left to heal spontaneously. The animals were killed 3, 28, and 40 days after surgery and a detailed morphological and morphometric study was performed on the perialveolar bone surrounding the wounds. Three days after surgery (inflammatory phase) the bone wounds were occupied by hemorragic and inflammatory cells in both the untreated and IP-treated bone defects. Twenty-eight days after surgery, bone formation was evident with new bone spiculae particularly concentrated in the area of the bone lesion closest to the adjacent periodontal ligament. Morphometric measurements of the areas occupied by new bone showed that the synthesis of perialveolar bone was significantly stimulated by IP. The repair of the bone defects by new bone formation progressed by day 40, but only in the presence of IP were the original holes almost completely repaired. Conversely, biostite and Htr did not influence promotion of new bone formation. In conclusion, the results of the present study are consistent with a role of IP in stimulating osteogenesis and suggest that this compound could represent a potential therapeutic tool to promote repair of injured perialveolar bone.

[Multiple endocrine neoplasia associated with multiple lipomas]

BACKGROUND

Multiple endocrine neoplasia type 1 (MEN-1) is characterized by tumors of the parathyroids, the neuroendocrine pancreas-duodenum and the anterior pituitary, but shows also a wide clinical variety of other symptoms.

CASE REPORT

We present a case of a 68-year-old woman with a 18 year history of MEN-1 consisting of gastrinoma and primary hyperparathyroidism. Beside these typical symptoms, the patient suffered from thyroid adenoma, malignant kidney tumor and multiple subcutaneous lipomas.

RESULT

While the number of autopsies declined from 113 in 1977 to 66 in 1984, the number of diagnostic techniques used increased continuously (94, 107, 118 and 140, amounting to 0.83, 1.34, 1.76 and 2.12 per patient). The premortal detection of abdominal abnormalities increased globally from 16.8 to 32.5%. This increase was largely due to better diagnosis of liver and gallbladder abnormalities which were in most cases of little relevance.

CONCLUSION

Whether these non-endocrine tumors are associated to MEN-1 is unclear and has to be tested by examining the chromosomal regions 11q13 and 11q24/25 of the tumors sample, in which the possible MEN-1 involved tumor suppressor genes are located.

Aromatase expression and activity in the human leukaemic cell line FLG 29.1

The recent observation that estrogen synthesis occurs in osteoblast-like cells has suggested the aromatase activity as a possible local modulator of bone remodeling in post-menopausal women. To provide further insights into the androstenedione conversion to estrogen in bone-derived cells, we examined the human leukaemic cell line FLG 29.1, which is induced to differentiate toward the osteoclastic phenotype by TPA and TGF-beta1. Southern blot of RT-PCR products with a 32P-labeled cDNA probe for the human aromatase demonstrated that FLG 29.1 cells express aromatase mRNA. The enzyme activity, determined by measuring [3H]H2O release from [3H]androstenedione, obeyed Michaelis-Menten kinetic with apparent Km and Vmax values ranging from 5 to 10 nM and from 200 to 400 fmol/mg protein/6 h. Gene expression, enzyme activity and protein immunoreactivity, evaluated by immunocytochemistry, were stimulated in a time-dependent fashion by 5% charcoal-stripped FCS and by either 1-100 nM TPA or 0.01-0.5 ng/ml TGF-beta1, with maximal responses after 2-3 h exposure. After 24 h incubation of FLG 29.1 cells in the absence of these stimuli the aromatase mRNA and the protein were barely detectable. These findings demonstrate that cells of the osteoclastic lineage synthesize estrogen in vitro and that local cytokines, such as TGF-beta1, are able to induce androstenedione conversion.