Mutant K-ras Regulates Cathepsin B Localization on the Surface of Human Colorectal Carcinoma Cells
Document Type
Article
Publication Date
2002
Publication Title
Neoplasia
Volume
5
Issue
6
First Page
507
Keywords
Cancer, cysteine professes, membrane-associated professes, caveolae, K-ras
Last Page
519
Abstract
Cathepsin B protein and activity are known to localize to the basal plasma membrane of colon carcinoma cells following the appearance of K-ras mutations. Using immunofluorescence and subcellular fractionation techniques and two human colon carcinoma cell lines - one with a mutated K-ras allele (HCT 116) and a daughter line in which the mutated allele has been disrupted (HKh-2) - we demonstrate that the localization of cathepsin B to caveolae on the surface of these carcinoma cells is regulated by mutant K-ras. In HCT 116 cells, a greater percentage of cathepsin B was distributed to the caveolae, and the secretion of cathepsin B and pericellular (membrane-associated and secreted) cathepsin B activity were greater than observed in HKh-2 cells. Previous studies established the light chain of annexin II tetramer, p11, as a binding site for cathepsin B on the surface of tumor cells. The deletion of active K-ras in HKh-2 cells reduced the steady-state levels of p11 and caveolin-1 and the distribution of p11 to caveolae. Based upon these results, we speculate that cathepsin B, a protease implicated in tumor progression, plays a functional role in initiating proteolytic cascades in caveolae as downstream components of this cascade (e.g., urokinase plasminogen activator and urokinase plasminogen activator receptor) are also present in HCT 116 caveolae.
DOI
10.1016/S1476-5586(03)80035-0
Recommended Citation
Cavallo-Medved, Dora; Dosescu, D; Linebaugh, J; Sameni, B E; and Sloane, Bonnie F., "Mutant K-ras Regulates Cathepsin B Localization on the Surface of Human Colorectal Carcinoma Cells" (2002). Neoplasia, 5, 6, 507-519.
https://scholar.uwindsor.ca/biologypub/31