Androgen-independent prostate cancer is resistant to therapy and is often metastatic. Here we studied the effect of deprivation of tyrosine and phenylalanine (Tyr/Phe), glutamine (Gln), or methionine (Met), in vitro on human DU145 and PC3 androgen-independent prostate cancer cells, and on nontumorigenic human infant foreskin fibroblasts and human prostate epithelial cells. Deprivation of the amino acids similarly inhibited growth of DU145 and PC3 cells, arresting the cell cycle at G0/G1. Met and Tyr/Phe deprivation induces apoptosis in DU145, but only Met deprivation induces apoptosis in PC3 cells. The growth of normal cells is inhibited, but no apoptosis is induced by amino acid deprivation. Tyr/Phe deprivation inhibits expression and phosphorylation of focal adhesion kinase (FAK) and extracellular-regulated kinase (ERK) in DU145 but not PC3 or normal cells. Met deprivation inhibits phosphorylation but not protein expression of FAK and ERK in PC3. Therefore, apoptosis of DU145 and PC3 cells by amino acid restriction is FAK and ERK dependent. Tyr/Phe and Met deprivation inhibits invasion of DU145 and PC3, but Gln deprivation only inhibits invasion of DU145 cells. This indicates that the inhibition of invasion is not dependent on induction of apoptosis. The inhibition of invasion by Tyr/Phe restriction in DU145 and Met restriction in PC3 is consistent with the inhibition on FAK/ERK signaling. The inhibition of Tyr/Phe restriction in PC3 and Gln restriction in DU145 is not associated with inhibition of FAK/ERK. This indicates that FAK/ERK-dependent and independent pathways are modulated by specific amino acid restriction. This study shows the potential for specific amino acid restriction to treat prostate cancer.
Resveratrol has been shown to have anticarcinogenic activity. We previously found that resveratrol inhibited growth and induced apoptosis in 2 human melanoma cell lines. In this study we determined whether resveratrol would inhibit human melanoma xenograft growth. Athymic mice received control diets or diets containing 110 micromol/L or 263 micromol/L resveratrol, 2 wk prior to subcutaneous injection of the tumor cells. Tumor growth was measured during a 3-wk period. Metabolism of resveratrol was assayed by bolus gavage of 75 mg/kg resveratrol in tumor-bearing and nontumor-bearing mice. Pellets containing 10-100 mg resveratrol were implanted into the mice, next to newly palpated tumors, and tumor growth determined. We also determined the effect of a major resveratrol metabolite, piceatannol, on experimental lung metastasis. Resveratrol, at any concentration tested, did not have a statistically significant effect on tumor growth. The higher levels of resveratrol tested (0.006% in food or 100 mg in slow-release pellets) tended to stimulate tumor growth (P = 0.08-0.09). Resveratrol and its major metabolites, resveratrol glucuronide and piceatannol, were found in serum, liver, skin, and tumor tissue. Piceatannol did not affect the in vitro growth of a murine melanoma cell line, but significantly stimulated the number of lung metastases when these melanoma cells were directly injected into the tail vein of the mouse. These results suggest that resveratrol is not likely to be useful in the treatment of melanoma and that the effects of phytochemicals on cell cultures may not translate to the whole animal system.
Background. The mechanisms responsible for the transformation of stable angina to unstable angina, a major cause of morbidity and mortality, are commonly believed to be plaque rupture and thrombosis. We determined whether additional mechanisms are operative by analysing the histopathology and immunohistopathology of coronary plaques retrieved by directional atherectomy of patients with unstable angina in whom no intraluminal thrombus was demonstrated by angiography.Methods and Results. The histological findings of atherectomy specimens from 34 patients with unstable angina were compared with those of 24 patients with postangioplasty restenosis, whose lesions are known to be composed of smooth muscle cells (SMCs), and 10 patients with stable angina, whose lesions contain
Abstract. Compared to basic fibroblast growth factor (bFGF), a widely distributed, broad spectrum mitogen and mesoderm inducer, acidic fibroblast growth factor (aFGF) is reported to have an essentially neural distribution and to be undetectable in the early embryo . In the present investigation, we used immunoblotting and immunochemistry to assess the cellular and tissue distributions of aFGF and bFGF in 11-20-d rat embryos.Immunoblotting of crude and heparin-bound embryo extracts revealed faint bands at the expected 17-18-kD and predominant bands at an apparent molecular mass of 26 to 28-kD (despite reducing conditions) using multiple specific antibodies for aFGF and bFGF. Pretreatment with 8 M urea yielded 18-20413 aFGF and bFGF and some 24-26-kD bFGF Immunoreactivity for both aFGF and bFGF was positive and similar in B ASIC fibroblast growth factor (bFGF)' and acidic fibroblast growth factor (aFGF, also known as heparinbinding growth factor 1) are closely related polypeptides that have a widespread distribution in tissues and have been extremely well conserved throughout evolution, a feature that suggests physiological importance (1-3, 5, 8, 26) . However, the precise biological functions ofbFGF and aFGF in vivo remain largely unknown . In vitro studies have shown thatthese two peptides have regulatory effects on many cellular functions, such as proliferation, differentiation, matrix formation, and cell movement (3,5,26,36) . Because each of these functions is ofcritical importance during embryonic development, these growth factors could play a major role in embryogenesis . Using biochemical and immunological methods, bFGF and its messenger RNA have been identified in amphibian oocytes and embryos and its mesoderm-inducing effect has been demonstrated (35-37, 55, 56) . Limited immunohistochemical studies in chicken and rat embryos have shown that the presence ofbFGF is associated with developmental events such as angiogenesis and early muscle morphogenesis (25,34,52) . For aFGF, no embryonic distribution has been reported (9, 25, 30, 34) .1. Abbreviations used in this paper: aFGF, acidic fibroblast growth factor ; bFGF, basic fibroblast growth factor.
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