Use of three-dimensional basement membrane cultures to model oncogene-induced changes in mammary epithelial morphogenesis

The development of breast carcinomas involves a complex set of phenotypic alterations in breast epithelial cells and the surrounding microenvironment. While traditional transformation assays provide models for investigating certain aspects of the cellular processes associated with tumor initiation and progression, they do not model alterations in tissue architecture that are critically involved in tumor development. In this review, we provide examples of how three-dimensional (3D) cell culture models can be utilized to dissect the pathways involved in the development of mammary epithelial structures and to elucidate the mechanisms responsible for oncogene-induced phenotypic alterations in epithelial behavior and architecture. Many normal mammary epithelial cell lines undergo a stereotypic morphogenetic process when grown in the presence of exogenous matrix proteins. This 3D morphogenesis culminates in the formation of well-organized, polarized spheroids, and/or tubules that are highly reminiscent of normal glandular architecture. In contrast, transformed cell lines isolated from mammary tumors exhibit significant deviations from normal epithelial behavior in 3D culture. We describe the use of 3D models as a method for both reconstructing and deconstructing the cell biological and biochemical events involved in mammary neoplasia.

The pediatric nephrotic syndrome spectrum: clinical homogeneity and molecular heterogeneity

Idiopathic nephrotic syndrome is the most common glomerular disorder of childhood. Recurrence of nephrotic syndrome immediately following renal transplantation is rapid, results in a high rate of graft loss, and represents the most severe form of nephrotic syndrome. This review discusses the molecular heterogeneity of pediatric nephrotic syndrome across the spectrum of disease activity. A schema is offered for a molecular approach to pediatric nephrotic syndrome, including immune-mediated and structural/genetic factors.

Evidence for the existence of IL-4 and IFN gamma secreting cells in the T cell repertoire of naive mice

The kinetics with which IgE responses develop in vivo following immunization of experimental animals indirectly support the existence of IL-4-secreting T cells as a normal component of the T cell repertoire. At the same time, studies of IL-4-secreting cell frequencies directly ex vivo have argued that T cells with the potential to become IL-4 secretors exist in vivo, in the form of precursors requiring stimulation and 4-12 days of culture as well as restimulation with mitogen or Ag before they become detectable as lymphokine-secreting cells. We demonstrate here that intravenous administration of low doses of anti-CD3 mAb 145-2C11 results in IL-4 production within 60 min of stimulation as demonstrated by Northern analysis of mRNA and a sensitive, selective bioassay (CT.4S cell proliferation) of biologically active IL-4 protein. Production of IL-4 is paralleled by IFN gamma synthesis, displaying similar kinetics. These findings, consistent with the presence of mature cells capable of IL-4 and IFN gamma synthesis in the T cell repertoire of naive mice, are supported by the observation that stimulation of spleen cells from naive mice with anti-CD3 mAb in vitro for 12 h also results in strong IL-4 and IFN gamma mRNA and protein synthesis. The data support and extend those obtained through analysis of cytokine mRNA synthesis alone, thereby providing evidence that "fresh" T cells are indeed capable of producing IL-4 directly ex vivo and are consistent with the existence of IL-4-secreting cells as a normal component of the T cell repertoire of naive mice.