Interleukin-2 expression in human carcinoma cell lines and its role in cell cycle progression

The role of endogenous interleukin-2 in proliferation of human carcinoma cell lines

“…These results taken together with our previously reported data of in vivo growth inhibition by rIL-2 (Rabinowich et al, 1992;Weidmann et al, 1992;Yasamura et al, 1994), indicate that both the Abs to the IL-2 binding site on the In contrast to the effects of exogenous IL-2 on tumour cell growth reported above, IL-2 made by tumour cells appeared to enhance their cell cycle progression (Reichert et al, 1998a). The presence in the cytoplasm of these tumour cells of both IL-2 and IL-2R was demonstrated in immunostaining (data for IL-2R are not shown), suggesting that the intracrine IL-2 pathway was operative in tumour cells.…”

“…The presence of IL-2 mRNA and protein in tumour cells in vitro and in situ has been previously demonstrated in our laboratory (Lin et al, 1995;Reichert et al, 1998aReichert et al, , 1998b. Also, endogenous IL-2 was detectable in the tumour cell cytosol by immunoassays at relatively low levels of 40-60 pg ml -1 per 5 × 10 6 cells disrupted by rapid freezing and thawing (Lin et al, 1995).…”

“…Previous observations from our laboratory indicated that the addition of exogenous IL-2 at high concentrations (in nM to µM quantities) or of antibodies (Abs) recognizing the IL-2 binding site on the IL-2Rβ chain expressed in carcinoma cell lines inhibited their growth (Rabinowich et al, 1992;Yasamura et al, 1994;Lin et al, 1995). In contrast, recent results showed that endogenous IL-2, produced by tumour cells in the absence of exogenous IL-2, behaved like a cell cycle-associated protein and was involved in promoting cell cycle progression in carcinomas (Reichert et al, 1998a). These data prompted us to investigate the role of endogenous IL-2 in tumour cell growth.…”

“…Kip1 cyclin-dependent kinase (CDK) inhibitor in mitotic cells (Reichert et al, 1998a). Previous results from other laboratories have also suggested that, similar to its role in proliferation of haematopoietic cells, IL-2 may be a growth hormone for tumour cells .…”

123I-Interleukin-2 uptake in squamous cell carcinoma of the head and neck carcinoma

“…[5][6][7] In SCCHN cell lines, expression of CD25 ϩ has been reported to be either absent, low, or high. [8][9][10][11] In only one study, respectively, by Wiedeman et al, human tissue SCCHN samples were studied. 10 In this study, a low to absent expression of CD25 was observed on SCCHN tumor cells; however, only four resection specimens were analyzed.…”