In:
Cancer Research, American Association for Cancer Research (AACR), Vol. 64, No. 15 ( 2004-08-01), p. 5301-5310
Abstract:
Tumorigenesis is associated with several changes that alter the cellular susceptibility to programmed cell death. Here, we show that immortalization and transformation sensitize cells in particular to the cysteine cathepsin-mediated lysosomal death pathway. Spontaneous immortalization increased the susceptibility of wild-type murine embryonic fibroblasts (MEFs) to tumor necrosis factor (TNF)-mediated cytotoxicity & gt;1000-fold, whereas immortalized MEFs deficient for lysosomal cysteine protease cathepsin B (CathB) retained the resistant phenotype of primary cells. This effect was specific for cysteine cathepsins, because also lack of cathepsin L (a lysosomal cysteine protease), but not that of cathepsin D (a lysosomal aspartyl protease) or caspase-3 (the major executioner protease in classic apoptosis) inhibited the immortalization-associated sensitization of MEFs to TNF. Oncogene-driven transformation of immortalized MEFs was associated with a dramatic increase in cathepsin expression and additional sensitization to the cysteine cathepsin-mediated death pathway. Importantly, exogenous expression of CathB partially reversed the resistant phenotype of immortalized CathB-deficient MEFs, and the inhibition of CathB activity by pharmacological inhibitors or RNA interference attenuated TNF-induced cytotoxicity in immortalized and transformed wild-type cells. Thus, tumorigenesis-associated changes in lysosomes may counteract cancer progression and enhance therapeutic responses by sensitizing cells to programmed cell death.
Type of Medium:
Online Resource
ISSN:
0008-5472
,
1538-7445
DOI:
10.1158/0008-5472.CAN-04-1427
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2004
detail.hit.zdb_id:
2036785-5
detail.hit.zdb_id:
1432-1
detail.hit.zdb_id:
410466-3
