No abstract

We previously found that 12-O-tetradecanoylphorbol-13-acetate (TPA)-enhanced invasion of Matrigel was associated with augmentation of cell motility but not with metalloproteinase activity in a highly metastatic variant (L-10) of human rectal adenocarcinoma cell line RCM-1. In a two-dimensional cell motility assay, TPA induced active L-10 cell locomotion with characteristic morphology; the cells moved outwards from the cell islands mainly as a localized coherent sheet of cells. The leading cells showed locomotor morphologies with fan-shaped leading lamellae while the following cells had cell contacts on all sides and appeared to lack leading lamellae. In the present ultrastructural study, the following cells frequently showed tapering cytoplasmic protrusions and leading lamella-like processes underlapping a preceding cell, indicating that the locomotion mechanism is almost the same for both the leading and following cells. For this type of locomotion as a coherent sheet we propose that localized modulation of cell-cell adhesion was induced such that wide intercellular gaps occurred at the lower portion of the cells to allow the cells to extend the tapering cytoplasmic processes and leading lamellae while close cell-cell contacts remained at the upper portion of the cells. These TPA-induced changes took place predominantly in the cells at the periphery of the cell islands, while the cells in the middle of the cell islands maintained close cell-cell contacts including complex interdigitation all around the cells, suggesting the modulation of TPA action by cell-cell interaction. Additionally, consistent with the evidence for junctional complexes between the cells moving outwards, the Lucifer-yellow dye transfer studies showed some, limited cell-cell coupling, suggesting the presence of at least some gap junctional intercellular communication in the moving cell sheets.

The cEVR results in this study suggest that high rates of sustained virological response can be achieved in retreated and treatment-naïve patients using DFPP in combination with PEG-IFN/RBV therapy. Results indicate that this therapy could be safely conducted, even in elderly patients.

Gastric distention as a result of patients drinking a glass of water is a simple and noninvasive method for improving the diagnostic accuracy of FDG-PET in patients with locally advanced gastric carcinoma.

We previously found that the enhanced activity to invade Matrigel upon stimulation with 12-O-tetradecanoylphorbol-13-acetate (TPA) was one of the major properties of a highly metastatic variant (L-10) of a human rectal adenocarcinoma cell line RCM-1. To clarify the mechanism of this enhancement, we examined the effect of TPA on 2 major biological factors involved in tumor cell invasion: cell motility and matrix-degrading metalloproteinase activity. The enhanced invasiveness was inhibited by protein-kinase-C inhibitors. TPA markedly enhanced both haptotactic response to type-IV collagen and motility on tissue-culture glass substrate of L-10 cells in a dose-response manner quite similar to that of TPA-enhanced invasion of Matrigel. On the other hand, TPA showed little enhancement of metalloproteinase production, which was assessed by gelatin- and casein-zymography, and of type-IV collagenolytic activity. Addition of TIMP (tissue inhibitors of metalloproteinase)-I inhibited TPA-enhanced invasion of Matrigel by only up to 13%. Thus, TPA treatment of L-10 cells enhanced invasion of Matrigel in association with augmentation of cell motility but did not enhance metalloproteinase activity.