Cellular bases of the antitumor activity of the novel taxane IDN 5109 (BAY59-8862) on hormone-refractory prostate cancer.

Taxane-based therapies appear to have a significant efficacy in clinical trials on hormone-refractory prostate carcinoma. In the present study, we investigated the cellular response of androgen-independent prostate carcinoma cell lines to the novel taxane IDN 5109 (BAY 59-8862) and evaluated its antitumor activity. In previous preclinical studies, this new paclitaxel (PTX) analogue was characterized by high tolerability and antitumor efficacy, ability to overcome multidrug resistance, and activity by oral administration. Upon treatment, DU145 and PC3 prostate carcinoma cell lines underwent a transient mitotic arrest. This was followed by G1 arrest and rapid occurrence of apoptosis in DU145 cells, whereas in PC3 cells, which are defective for the postmitotic checkpoint, a slow cell death was preceded by DNA endoreduplication. At the biochemical level, such events were associated with tubulin polymerization, activation of the mitosis-promoting factor, and phosphorylation of Bcl-X(L)/Bcl-2/Raf-1. In addition, IDN 5109 shared with PTX the ability to down-regulate the expression of the two potent angiogenic factors vascular endothelial growth factor and basic fibroblast growth factor. These findings indicated that IDN 5109 affected the same pathways involved in the cellular response to PTX and suggested that an antiangiogenic effect mediated by inhibition of paracrine stimulation of endothelial cells might contribute to the antitumor effect of both drugs. In in vivo experiments, the new taxane displayed a superior and more persistent effect compared with PTX against DU145 tumor xenografts. Such an effect was associated with pronounced reduction of the tumor microvessel density, superior to that achieved by PTX. These results support a potential therapeutic advantage of IDN 5109 over PTX against hormone-refractory prostate carcinoma.     

Tissue protein turnover during liver carcinogenesis

Overall rates of tissue protein degradation in vivo during chemicalhepatocarcinogenesis were estimated by a double-isotope methodas well as from the accumulation of peptide intermediates inprotein degradation induced by bestatin. Several parametersestimating rates of cell proliferation and cell loss have beenmeasured in parallel. The two procedures adopted consistentlyindicated that protein turnover was significantly slowed downthrough the whole observation period (12 months after the initiatingadministration of DENA) in both ‘preneoplastic’nodules and hepatomas as compared with control livers or perinodulartissue. Such a difference may confer a selective growth advantageto ‘preneoplastic’ and tumoral cells. Since proteindegradation rates did not appreciably differ between nodulesand hepatomas, either such advantage originated from some earlystep in the carcinogenetic process or it merely reflected theproliferative events in the two cell populations. Yet neitherliver nodules nor hepatomas were characterized by very highrates of cell proliferation, however much increased with respectto control liver.     

The plant-type ferredoxin-NADP+ reductase/ferredoxin redox system as a possible drug target against apicomplexan human parasites

Apicomplexa are unicellular, obligate intracellular parasites of great medical importance. They include human pathogens like Plasmodium spp., the causative agent of malaria, and Toxoplasma gondii, an opportunistic parasite of immunosuppressed individuals and a common cause of congenital disease (toxoplasmosis). They alone affect several hundred million people worldwide so that new drugs, especially for plasmodial infections, are urgently needed. This review will focus on a recently emerged, potential drug target, a plant-type redox system consisting of ferredoxin-NADP(+) reductase (FNR) and its redox partner, ferredoxin (Fd). Both reside in an unique organelle of these parasites, named apicoplast, which is of algal origin. The apicoplast has been shown to be required for pathogen survival. In addition to other pathways already identified in this compartment, the FNR/Fd redox system represents a promising drug target because homologous proteins are not present in host organisms. Furthermore, a wealth of structural information exists on the closely related plant proteins, which can be exploited for structure-function studies of the apicomplexan protein pair. T. gondii and P. falciparum FNRs have been cloned, and the T. gondii enzyme was shown to be a flavoprotein active as a NADPH-dependent oxidoreductase. Both phylogenetic and biochemical analyses indicate that T. gondii FNR is similar in function to the isoform present in non-photosynthetic plastids whereby electron flow is from NADPH to oxidized Fd. The resulting reduced Fd is then presumably used as a reductant for various target enzymes whose nature is just starting to emerge. Among the likely candidates is the iron-sulfur cluster biosynthesis pathway, which is also located in the apicoplast and dependent on reducing power. Furthermore, lipoic acid synthase and enzymes of the isoprenoid biosynthetic pathway may be other conceivable targets. Since all these metabolic steps are vital for the parasite, blocking electron flow from FNR to Fd by inhibition of either FNR activity or its molecular interaction with Fd should also interfere with these pathways, ultimately killing the parasite. Although the three-dimensional structure of FNR from T. gondii is not yet known, experimental and computational evidence shows that apicomplexan and plant enzymes are very similar in structure. Furthermore, single amino acid changes can have profound effects on the enzyme activity and affinity for Fd. This knowledge may be exploited for the design of inhibitors of protein-protein interaction. On the other hand, specifically tailored NAD(P) analogues or mimetics based on previously described substances might be useful lead compounds for apicomplexan FNR inhibitors.     

Transient receptor potential vanilloid type 1 (TRPV1) expression changes from normal urothelium to transitional cell carcinoma of human bladder

OBJECTIVE: To investigate possible changes in the expression of the transient receptor potential vanilloid type 1 (TRPV1) from normal urothelium to transitional cell carcinoma (TCC) of human bladder. METHODS: Specimens from normal bladder (n=13, mean age 62 yrs), superficial TCC (n=16, mean age 62,4 yrs) and muscle invasive bladder cancer (n=12, mean age 67 yrs), were obtained by multiple cold cup and full-thickness biopsy during open surgery. All the specimens were processed for H&E staining, immunohistochemistry and Western Blot analysis. RESULTS: In controls, the urothelium showed a labelling whose intensity was higher in the superficial cells than in the basal and club-shaped ones. In the superficial TCC, the urothelium showed a reduced labelling intensity. In the muscle invasive TCC, a very light labelling was occasionally detected in scattered superficial cells and no labelling was present in the basal cells and in those that had invaded the muscle. In controls, Western Blot analysis recognized two thick, intensely stained bands, with a molecular weight of approximately 100 and 95 kDa. In all superficial TCC there were two bands similar to control ones and in the muscle invasive two very thin, lightly stained bands. No band was detected in the patients staged as pT4. CONCLUSION: These data demonstrated a progressive loss of TRPV1 expression in the urothelium as TCC stage increased and cell differentiation was lower. Future studies will establish the importance of this loss for TCC differentiation and progression.     

Decrease in pathology and progression of scrapie after immunisation with synthetic prion protein peptides in hamsters

Effective therapy for prion diseases is currently unavailable. Recently, vaccination was shown to be effective in mouse models of a particular neurodegenerative conditions: Alzheimer's disease (AD). Here, we report that vaccination with synthetic oligopeptides homologous to the hamster (Mesocricetus auratus) prion protein augments survival time in animals infected intraperitoneally with 263K scrapie agent. For each hamster included in the study, prion-specific serum antibodies as well as deposition of pathological prion protein (PrP(res)), glial fibrillary acidic protein (GFAP), and mRNA expression for cytokines (TNF alpha, IL-1beta, IL-10) in brain tissues were evaluated. In immunized animals, increased survival after challenge was associated with a reduction of cerebral lesion, PrP deposition and GFAP expression; in these animals, anti-prion protein peptide antibody levels were increased, and the expression of pro-inflammatory cytokines (TNF alpha and IL-1beta) was reduced. Vaccination could be an effective therapeutic approach to postpone disease onset.     

Ghrelin, leptin and IGF-I levels in breast-fed and formula-fed infants in the first years of life

AIM: To establish ghrelin, leptin and IGF-I serum levels in breastfed (BF) and formula-fed (FF) infants during the first period of life. METHODS: A cross-sectional study was conducted on fasting blood venous samples obtained from exclusively BF (n=106) and FF (n=100) infants to measure total ghrelin (RIA test), leptin (RIA test) and IGF-I (chemiluminescence). Anthropometrical measurements of weight, length and cranial circumference were performed. RESULTS: During the first 4 mo of life, FF infants compared to BF ones showed higher ghrelin levels (2654.86 vs 2132.96 pg/ml; p<0.032), higher IGF-I levels (3.73 vs 3.15 ng/ml; p=0.00) and lower leptin levels (0.68 vs 1.16 ng/ml; p<0.04). Leptin values were higher in females than in males (0.80 vs 0.47 ng/ml; p<0.03), while no gender-related difference was found for ghrelin and IGF-I. No differences were found in anthropometrical measurements comparing the two groups of infants. A multiple regression analysis showed an inverse correlation between ghrelin and leptin values (p<0.04) and between IGF-I and leptin levels (p=0.00). CONCLUSION: Our finding suggests that breastfeeding influences hormones such as ghrelin, leptin and IGF-I in infancy, mainly during the first 4 mo of life. Further evidence is needed to confirm and clarify the role of a protective link from mother to infants as seen in our observations.     

Rituximab in patients with mucosal-associated lymphoid tissue-type lymphoma of the ocular adnexa

Eight patients with ocular adnexal mucosal-associated lymphpid tissue (MALT) lymphoma were treated with rituximab, at diagnosis (n=5) or relapse (n=3). All untreated patients achieved lymphoma regression, while relapsing patients had no benefit. Four responding patients experienced early relapse. The median time to progression was 5 months. The efficacy of rituximab in ocular adnexal lymphoma is lower than that reported for gastric MALT lymphomas.