RESUMEN
Kaposi sarcoma (KS), the most common AIDS-associated malignancy, is a multifocal tumor characterized by deregulated angiogenesis, proliferation of spindle cells, and extravasation of inflammatory cells and erythrocytes. Kaposi sarcoma-associated herpesvirus (KSHV; also human herpesvirus-8) is implicated in all clinical forms of KS. Endothelial cells (EC) harbor the KSHV genome in vivo, are permissive for virus infection in vitro, and are thought to be the precursors of KS spindle cells. Spindle cells are rare in early patch-stage KS lesions but become the predominant cell type in later plaque- and nodular-stage lesions. Alterations in endothelial/spindle cell physiology that promote proliferation and survival are thus thought to be important in disease progression and may represent potential therapeutic targets. KSHV encodes genes that stimulate cellular proliferation and migration, prevent apoptosis, and counter the host immune response. The combined effect of these genes is thought to drive the proliferation and survival of infected spindle cells and influence the lesional microenvironment. Large-scale gene expression analyses have revealed that KSHV infection also induces dramatic reprogramming of the EC transcriptome. These changes in cellular gene expression likely contribute to the development of the KS lesion. In addition to KS, KSHV is also present in B cell neoplasias including primary effusion lymphoma and multicentric Castleman disease. A combination of virus and virus-induced host factors are similarly thought to contribute to establishment and progression of these malignancies. A number of lymphocyte- and EC-based systems have been developed that afford some insight into the means by which KSHV contributes to malignant transformation of host cells. Whereas KSHV is well maintained in PEL cells cultured in vitro, explanted spindle cells rapidly lose the viral episome. Thus, endothelial cell-based systems for studying KSHV gene expression and function, as well as the effect of infection on host cell physiology, have required in vitro infection of primary or life-extended EC. This chapter includes a review of these in vitro cell culture systems, acknowledging their strengths and weaknesses and putting into perspective how each has contributed to our understanding of the complex KS lesional environment. In addition, we present a model of KS lesion progression based on findings culled from these models as well as recent clinical advances in KS chemotherapy. Thus this unifying model describes our current understanding of KS pathogenesis by drawing together multiple theories of KS progression that by themselves cannot account for the complexities of tumor development.
Asunto(s)
Células Endoteliales/virología , Herpesvirus Humano 8/fisiología , Linfocitos/virología , Sarcoma de Kaposi/etiología , Animales , Línea Celular , Linaje de la Célula , Progresión de la Enfermedad , Regulación de la Expresión Génica , Herpesvirus Humano 8/genética , Humanos , Linfoma/virología , Sarcoma de Kaposi/clasificación , Sarcoma de Kaposi/patología , Sarcoma de Kaposi/virología , Telomerasa/fisiologíaRESUMEN
This study examined the response to acidic conditions of four gonococcal isolates -NRL38874 (Proto/IB-2), NRL38884 (Pro/IA-2), NRL38953 (Proto/IB-3) and NRL39029 (Pro/IA-3) - obtained from various sites in patients in whom a diagnosis of pelvic inflammatory disease had been made by laparoscopic examination. Acid tolerance of the clinical isolates was strain and growth phase dependent. Growth of the four strains on solid media was undetectable below pH 5.8. In liquid culture, strain NRL38884 did not survive below pH 5.2; strains NRL38874, NRL38953 and NRL39029 survived to pH 4.5. Between pH 4.2 and pH 5.1, the latter three strains exhibited a peak in survival at pH 4.6-4.7 during log phase, suggesting that there may be a distinct acid tolerance system operating at this pH. SDS-PAGE of whole-cell, total membrane and outer-membrane fractions of the four strains prepared from pH 7.2 and pH 6.1 plate cultures revealed numerous differences in protein composition. Acidic conditions reduced the expression of the reduction modifiable outer-membrane protein Rmp, and induced the expression of many membrane proteins, including gonococcal hsp63. Immunoblotting studies with matched serum samples and strains from patients with pelvic inflammatory disease indicated that IgG recognition of outer-membrane components from strains cultured in acidic and neutral conditions was quite different. The results suggest that the immune system interacts with unique outer-membrane constituents on gonococci colonising sites at different pH.
Asunto(s)
Gonorrea/microbiología , Neisseria gonorrhoeae/crecimiento & desarrollo , Enfermedad Inflamatoria Pélvica/microbiología , Anticuerpos Antibacterianos/sangre , Anticuerpos Antibacterianos/inmunología , Proteínas de la Membrana Bacteriana Externa/biosíntesis , Proteínas de la Membrana Bacteriana Externa/inmunología , Western Blotting , Medios de Cultivo , Regulación hacia Abajo , Electroforesis en Gel de Poliacrilamida , Femenino , Humanos , Concentración de Iones de Hidrógeno , Sueros Inmunes/inmunología , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Masculino , Neisseria gonorrhoeae/inmunología , Regulación hacia ArribaRESUMEN
The remarkable anticancer drug dolastatin 10 (1a) from the Indian Ocean sea hare Dolabella auricularia is currently undergoing phase I clinical trials. Thirty-eight new structural modifications of this unusual peptide have been synthesized and evaluated against a variety of human and murine cancer cell lines, and for their ability to inhibit tubulin polymerization and vinblastine and GTP binding to tubulin. Dolastatin 10 and one structural modification was found to have antifungal activity, while one other structural modification of the parent compound exhibited antibacterial activity. Some of the new peptides approximated the antineoplastic potency of dolastatin 10, especially those based on replacement of the Doe unit with Met, Phe or an appropriately substituted phenylethylamide.
Asunto(s)
Antineoplásicos/farmacología , Oligopéptidos/farmacología , Animales , Antibacterianos , Antiinfecciosos/química , Antiinfecciosos/farmacología , Antineoplásicos/química , Cryptococcus neoformans/efectos de los fármacos , Depsipéptidos , Diseño de Fármacos , Ensayos de Selección de Medicamentos Antitumorales , Femenino , Humanos , Ratones , Pruebas de Sensibilidad Microbiana , Micrococcus luteus/efectos de los fármacos , Oligopéptidos/síntesis química , Oligopéptidos/química , Relación Estructura-Actividad , Tubulina (Proteína)/química , Células Tumorales Cultivadas/efectos de los fármacosRESUMEN
Spongistatin 1, a macrocyclic lactone polyether from the marine sponge Hyrtios erecta, was fungicidal for a variety of opportunistic yeasts and filamentous fungi, including strains resistant to amphotericin B, ketoconazole and flucytosine. In broth macrodilution assays, MICs ranged from 0.195 to 12.5 microg/ml, and minimum fungicidal concentrations ranged from 3.12 to 25 microg/ml. Initial disk diffusion screens with six related macrocyclic lactone polyethers from H. erecta and Spirastrella spinispirulifera, revealed that these polyethers were also antifungal. The fungicidal activity of spongistatin 1 was confirmed in killing kinetics studies, where killing of Candida albicans and Cryptococcus neoformans occurred within 6 and 12 h, respectively. During the killing kinetics experiments, non-treated C. albicans maintained the yeast morphology. However, elongated forms resembling germ tubes were the predominant morphologic form in spongistatin 1-treated C. albicans cultures. The spongistatins show promise as potential antifungal agents and as probes to study fungal morphogenesis and nuclear division.