Differential effects of serine proteases on the migration of normal and tumor cells: implications for tumor microenvironment.

The supporting role of proteases in tumor progression and invasion is well known; however, the use of proteases as therapeutic agents has also been demonstrated. In this article, the authors report on the differential effects of exogenous serine proteases on the motility of tumor and normal cells. The treatment of normal and tumor cells with a single dose of pancreatic serine proteases, trypsin (TR) and chymotrypsin (CH), leads to a concentration-dependent response by cells, first accelerating and then slowing mobility.

Constitutive and ligand-induced nuclear localization of oxytocin receptor.

Oxytocin receptor (OTR) is a membrane protein known to mediate oxytocin (OT) effects, in both normal and neoplastic cells. We report here that human osteosarcoma (U2OS, MG63, OS15 and SaOS2), breast cancer (MCF7), and primary human fibroblastic cells (HFF) all exhibit OTR not only on the cell membrane, but also in the various nuclear compartments including the nucleolus. Both an OTR-GFP fusion protein and the native OTR appear to be localized to the nucleus as detected by transfection and/or confocal immunofluorescence, respectively.

Evidence of a novel intracrine mechanism in angiotensin II-induced cardiac hypertrophy.

Angiotensin II (Ang II) has a significant role in regulating cardiac homeostasis through humoral, autocrine and paracrine pathways, via binding to the plasma membrane AT1 receptor. Recent literature has provided evidence for intracrine growth effects of Ang II in some cell lines, which does not involve interaction with the plasma membrane receptor. We hypothesized that such intracrine mechanisms are operative in the heart and likely participate in the cardiac hypertrophy induced by Ang II.

Transformation of MC3T3-E1 cells following stress and transfection with pSV2neo plasmid.

A continuous cell line, MC3T3-E1 cells, originally derived from murine calvaria bones, loses its osteogenic properties as a result of extended passage number under stress conditions. These aged/stressed MC3T3-S cells, although nontumorigenic, do not display some of the osteogenic properties characteristic of the MC3T3-E1 cells. Altered properties include low expression of alkaline phosphatase, diminished collagen synthesis and inability to form mineralized nodules in vitro.