Cadmium influences the 5-Fluorouracil cytotoxic effects on breast cancer cells.

The aim of the research was to evaluate a heavy metal, Cadmium (Cd), which was used to produce alterations in human breast cancer cell line MCF-7. Moreover, we analyzed both immunohistochemical and ultrastructural alterations induced by the antineoplastic drug, 5-Fluorouracil (5-FU), after exposure to different concentrations of Cadmium. Also, we compared the effects of these compounds on actin and tubulin cytoskeleton proteins. Under ultramicroscopic observation, control cells looked polymorphous with filopodia. In cells already treated with small concentrations of Cd, after brief times of incubation, we observed an intense metabolic activity with larger, clearer, and elongated mitochondria characterized by thin and numerous dilated cristae. 5-FU-treated cells showed cytotoxicity signs with presence of pore-like alterations in the cell membrane and evident degeneration of cytoplasm and cell nuclei. The addition of 5-FU (1.5 µM) to the cells treated with Cd (5 µM-20 µM) did not induce significant ultrastructural changes in comparison with cells treated only with Cd. In Cd+5FU-treated cells mitochondria with globular aspect and regular cristae indicated the active metabolic state. In cells treated only with Cd we observed alterations in actin distribution, while tubulin branched out throughout the cytoplasm. With the association of Cd+5FU, we observed less morphological alterations in both tubulin and actin cytoskeleton proteins. Although the mechanism remains unknown at present, our findings suggest that Cd prevents the cytotoxic effect of 5-FU on breast cancer cells. These preliminary results could have an important clinical application in patients with breast cancer.

Low cadmium concentration in whole blood from residents of northern Sardinia (Italy) with special reference to smoking habits.

INTRODUCTION: The present study was initiated to investigate the cadmium concentrations in whole blood of Northern Sardinian, non-occupationally exposed adult subjects. Sardinia is a large Italian island which differs genetically and environmentally from other mainland Italian areas. METHODS: Two hundred and forty-three adults (157 females and 86 males) were selected in the study area from subjects who were undergoing blood collection for laboratory analysis during the period January 2005-May 2005. Whole blood was analysed by graphite furnace atomic absorption spectrometer equipped with a Zeeman-effect background corrector (Perkin Elmer ZLS5100) and an auto sampler. The adopted analytical procedure uses the Stabilized Platform Temperature Furnace (STPF) technique. RESULTS: The mean value of Blood Cadmium Concentration (BCdC), expressed as Geometric Mean, was 0.32 pg/l (CI 95%: 0.31-0.34 l) in non-smokers to 034 pg/l (CI 95%: 0.30-0.39 pg/l) in ex-smokers up to 0.47 gg/ll(CI 95%: 0.42-0.53 pg/l) in smokers (p < 0.0001). DISCUSSION: The results show that BCdC levels in Northern Sardinian non-occupationally exposed adults are lower than levels found in many other regions, including those within Italy. Nevertheless, similar values have been detected in other European countries and cities. CONCLUSIONS: In relation to other reports in which data were analysed by strata for smoking habit and age, we found similar BCdC values among non smokers. However, Sardinian smokers seem to show lower levels of blood cadmium.

Contractile regulatory proteins tropomyosin and troponin-T as indicators of the modulatory role of retinoic acid.

Retinoic acid (RA), the active metabolite of vitamin A, plays a significant role in regulating cardiac form and function throughout the life of the organism. Both cardiac morphogenesis and myocardial differentiation are affected by alterations in RA homeostasis. In order to test the effect of all-trans RA and 13-cis RA on cardiomyocyte differentiation, we studied the level and the subcellular compartmentalization of alpha-tropomyosin and troponin-T proteins in cultures of chick embryo cardiomyocytes obtained from Hamburger and Hamilton's (HH) stage 22, 32 and 40 embryos. The retinoids increased the levels of alpha-tropomyosin and troponin-T in the cytoplasmic and cytoskeletal fractions of cells at all three stages of development. The greatest increases in alpha-tropomyosin occurred in the cytoplasmic fraction in HH22 cells cultured for 24 h with all-trans RA or 13-cis RA, whereas the greatest increases in troponin-T were found in the cytoplasmic fraction of HH32 cells exposed to retinoids for 24 h. In cultures treated for 48 h with retinoids, the levels of alpha-tropomyosin and troponin-T showed significant increases in the cytoplasmic compartment of cells treated in HH32-with respect to the control values. These findings are further evidence that RA plays a modulating role in the formation and reorganization of sarcomeric proteins during the process of cardiomyocyte maturation.

Modulation of HLA class I expression in multidrug-resistant human rhabdomyosarcoma cells.

An abnormal HLA expression has been detected in some tumors including rhabdomyosarcoma (RMS). Classical cytotoxic treatment of these tumors, the most common childhood soft tissue malignancy, may induce multidrug resistance (MDR) associated with the expression of a 170-kDa membrane-associated glycoprotein (P-glycoprotein). In order to analyse the connection between modulation of HLA expression and the development of the MDR phenotype mediated by P-glycoprotein in RMS, we used three resistant RMS cell lines; two of these resistant cell lines (TE.32.7.DAC and RD-DAC) were established by in vitro exposure to actinomycin D, a drug of choice in the treatment of RMS; the resistant RMS- GR cell line was established from an embryonal RMS tumor after polychemotherapy. Our results showed that all the resistant cell lines showed a significant increase in the expression of HLA class I surface antigens in comparison to drug-sensitive cells. Blockade of P-glycoprotein with verapamil led to a decrease in HLA class I expression in RMS resistant cell lines. However, no modulation of HLA class II expression was observed in any of the three analyzed cell lines. These findings support the hypothesis that the development of resistance mediated by mdr 1/P-glycoprotein, directly influences the expression of HLA class I in RMS cells, inducing to upregulation. This effect may be relevant to the application in RMS of immunotherapy against tumor-associated antigens presented by HLA class I molecules.

Overexpression and activation of hepatocyte growth factor/scatter factor in human non-small-cell lung carcinomas.

Hepatocyte growth factor/scatter factor (HGF/SF) stimulates the invasive growth of epithelial cells via the c-MET oncogene-encoded receptor. In normal lung, both the receptor and the ligand are detected, and the latter is known to be a mitogenic and a motogenic factor for both cultured bronchial epithelial cells and non-small-cell carcinoma lines. Here, ligand and receptor expression was examined in 42 samples of primary human non-small-cell lung carcinoma of different histotype. Each carcinoma sample was compared with adjacent normal lung tissue. The Met/HGF receptor was found to be 2 to 10-fold increased in 25% of carcinoma samples (P = 0.0113). The ligand, HGF/SF, was found to be 10 to 100-fold overexpressed in carcinoma samples (P < 0.0001). Notably, while HGF/SF was occasionally detectable and found exclusively as a single-chain inactive precursor in normal tissues, it was constantly in the biologically-active heterodimeric form in carcinomas. Immunohistochemical staining showed homogeneous expression of both the receptor and the ligand in carcinoma samples, whereas staining was barely detectable in their normal counterparts. These data show that HGF/SF is overexpressed and consistently activated in non-small-cell lung carcinomas and may contribute to the invasive growth of lung cancer.

[Immunohistochemical observations on tubulin and alpha actinin during mitosis of cultured fibroblasts]. / Osservazioni immunoistochimiche della tubulina e dell'alpha-actinina durante la mitosi di fibroblasti in cultura.

In this work we studied alpha-actinin and tubulin sites in rabbit fibroblasts in culture. Antibodies anti-alpha-actinin were used for indirect PAP-reaction while antibodies anti-tubulin were used for indirect immunofluorescence method. The observations were carried out by light microscopy, phase-contrast and interference-contrast microscopy, with regard to actinin, and by fluorescence microscopy, with regard to tubulin. During the early mitotic phase, alpha-actinin is localized all over the cell membrane of the fibroblasts, forming a sort strong protective cap, while during diacinesis it forms only rings, localizing below the cell membrane and the philopodia. Thus tubulin forms the bundle fibres during mitotic phases.