Comparison of the malaria parasite and mammalian protein prenyltransferases and their cellular substrates is important for establishing this enzyme as a target for developing antimalarial agents. Nineteen heptapeptides differing only in their carboxyl-terminal amino acid were tested as alternative substrates of partially purified Plasmodium falciparum protein farnesyltransferase. Only NRSCAIM and NRSCAIQ serve as substrates, with NRSCAIM being the best. Peptidomimetics, FTI-276 and GGTI-287, inhibit the transferase with IC 50 values of 1 and 32 nM, respectively. Incubation of P. falciparum-infected erythrocytes with [ 3 H]farnesol labels 50-and 22-28-kDa proteins, whereas [ 3 H]geranylgeraniol labels only 22-28-kDa proteins. The 50-kDa protein is shown to be farnesylated, whereas the 22-28-kDa proteins are geranylgeranylated, irrespective of the labeling prenol. Protein labeling is inhibited more than 50% by either 5 M FTI-277 or GGTI-298. The same concentration of inhibitors also inhibits parasite growth from the ring stage by 50%, decreases expression of prenylated proteins as measured with prenyl-specific antibody, and inhibits parasite differentiation beyond the trophozoite stage. Furthermore, differentiation specific prenylation of P. falciparum proteins is demonstrated. Protein labeling is detected predominantly during the trophozoite to schizont and schizont to ring transitions. These results demonstrate unique properties of protein prenylation in P. falciparum: a limited specificity of the farnesyltransferase for peptide substrates compared with mammalian enzymes, the ability to use farnesol to label both farnesyl and geranylgeranyl moieties on proteins, differentiation specific protein prenylation, and the ability of peptidomimetic prenyltransferase inhibitors to block parasite differentiation.Malaria continues to be a major disease in tropical areas of the world. Parasite resistance to current drugs used in the treatment of malaria has lead investigators to seek out new drug targets. Among those targets are proteins and enzymes, which are necessary for cellular division and differentiation. Such targets include the protein prenyltransferases, which are necessary for the post-translational modification of proteins involved in the signal transduction pathways and in regulation of DNA replication and cell cycling (1-3). These enzymes are currently a major focus of efforts to design drugs that inhibit unregulated cell growth in cancer (4, 5). Several candidate compounds show great promise as antitumor drugs and are currently being tested in clinical trials. The potential for the application of such drugs to inhibit malarial parasite division and differentiation motivates one to examine the properties of the protozoan enzyme with the goal of identifying unique features of this enzyme that would make it a target for the development of parasite-specific drugs.A variety of proteins including small G-proteins, such as Ras, Rac, Rap, Rho, Rab (6), heterotrimeric G protein ␥ subunits (7), nuclear lamins (8), prot...

Purpose More effective, less toxic treatments for recurrent ovarian cancer (OVCA) are needed. Although >60% of OVCAs express the estrogen receptor (ER), ER-targeted drugs have been disappointing due to drug resistance. In other estrogen-sensitive cancers, estrogen activates Src to phosphorylate p27 promoting its degradation and increasing cell cycle progression. Since Src is activated in most OVCAs, we investigated whether combined Src and ER blockade by saracatinib and fulvestrant would circumvent antiestrogen resistance. Experimental Design ER and Src were assayed in 338 primary OVCAs. Dual ER and Src blockade effects on cell cycle, ER target gene expression, and survival were assayed in ERα+ OVCA lines, a primary human OVCA culture in vitro, and on xenograft growth. Results Most primary OVCAs express ER. Src activity was greater in OVCA lines than normal epithelial lines. Estrogen activated Src, ER-Src binding and ER translocation from cytoplasm to nucleus. Estrogen mediated mitogenesis was via ERα, not ERβ. While each alone had little effect, combined saracatinib and fulvestrant increased p27, inhibited cyclin E-Cdk2 and cell cycle progression. Saracatinib also impaired induction of ER-target genes Myc and FOSL1; this was greatest with dual therapy. Combined therapy induced autophagy and more effectively inhibited OVCA xenograft growth than monotherapy. Conclusions Saracatinib augments effects of fulvestrant by opposing estrogen-mediated Src activation and target gene expression, increasing cell cycle arrest and impairing survival, all of which would oppose antiestrogen resistance in these ER+ OVCA models. These data support further pre-clinical and clinical evaluation of combined fulvestrant and saracatinib in OVCA.

http://dx.doi.org/10.5216/ree.v14i2.12977A segurança do paciente é temática, vem sendo incluída nas práticas do cuidado em saúde, como uma estratégia para orientar medidas que promovam a segurança da criança hospitalizada. O objetivo desta pesquisa foi descrever os eventos adversos identificados pelo familiar/cuidador em uma Unidade de Tratamento Intensivo Pediátrico (UTIP). Trata-se de pesquisa qualitativa exploratório-descritiva realizada com treze familiares/cuidadores em um hospital pediátrico de Porto Alegre-RS, no período de março a abril de 2009. Utilizou-se entrevista semiestruturada como técnica de coleta dados que foram analisados mediante análise do tipo temática. Das informações emergiram as seguintes categorias: Falhas no processo de comunicação; Práticas não seguras relacionadas à atuação profissional; Requisitos para segurança do paciente na UTIP. A criança neste ambiente encontra-se exposta frente à assistência ofertada. Acredita-se que a segurança da criança hospitalizada em UTIP necessita da incorporação de práticas de cuidado seguro como cultura institucional direcionada a prevenir eventos adversos.