Jh. Finke et al., Tumor-induced sensitivity to apoptosis in T cells from patients with renalcell carcinoma: Role of nuclear factor-kappa B suppression, CLIN CANC R, 7(3), 2001, pp. 940S-946S
Antitumor immunity fails to adequately develop in many cancer patients, inc
luding those with renal cell carcinoma (RCC), A number of different mechani
sms have been proposed to explain the immune dysfunction observed in cancer
patient T cells. Here we show that T cells from RCC patients display incre
ased sensitivity to apoptosis, Tumorinfiltrating lymphocytes (TILs) display
the most profound sensitivity, because 10-15% of those cells are apoptotic
when assessed by terminal deoxynucleotidyltransferase-mediated: nick end l
abeling in situ, and the number of apoptotic TILs further increases after 2
4 h of culture. Peripheral blood T cells from RCC patients are not directly
apoptotic, although T lymphocytes derived from 40% of those individuals un
dergo activation-induced cell death (AICD) upon lit vitro stimulation with
phorbol myristate acetate and ionomycin, This is in contrast to T cells fro
m normal individuals, which are resistant to AICD, TILs and peripheral bloo
d T cells from RCC patients also exhibit impaired activation of the transcr
iption factor, nuclear factor (NF)-kappaB, Additional findings presented he
re indicate that the heightened sensitivity of patient T cells to apoptosis
may be tumor induced, because supernatants from RCC explants sensitize, an
d in some instances directly induce, normal T cells to apoptosis, These sam
e supernatants also inhibit NF-kappaB activation. RCC-derived gangliosides
may represent one soluble tumor product capable of sensitizing T cells to a
poptosis, Pretreatment with neuraminidase, but not proteinase K, abrogated
the suppressive effects of tumor supernatants on both NF-kappaB activation
and apoptosis, Additionally, gangliosides isolated from tumor supernatants
not only inhibited NF-kappaB activation but also sensitized T cells to AICD
. These findings demonstrate that tumor- derived soluble products, includin
g gangliosides, may contribute to the immune dysfunction of T cells by alte
ring their sensitivity to apoptosis.