CD133(+) human pulmonary adenocarcinoma cells induce apoptosis of CD8(+) T cells by highly expressed galectin-3.
OBJECTIVE
To investigate the expression and function of Galectin-3 (Gal-3) in CD133(+) pulmonary adenocarcinoma.


METHODS
CD133(+) pulmonary adenocarcinoma cells were separated by MACS from excised pulmonary adenocarcinoma specimens of 11 patients. The percentage of CD133(+) cells in different cells population was determined by flow cytometry (FCM). Expression of Gal-3 in cancer cells was detected by Fluorescence Quantitation RT-PCR (FQRT-PCR) and Western blot whereas extracellular expression was detected by ELISA. CD133(+) cells were transfected with Gal-3 specific siRNA to explore the affects of Gal-3 inhibition on cancer cell growth and induction of CD8(+) T cell apoptosis.


RESULTS
Cells expressing CD133 constituted 90% of the CD133(+) subpopulation after separation by MACS whereas they made up only 1.2% of the unsorted cell population. Expression of Gal-3 was 1.24 fold, 1.5 fold and 2 fold higher in CD133(+) cells than in CD133(-) cells as detected by FQRT-PCR, Western blot and ELISA respectively (p < 0.05 for each). The supernatants of CD133(+) cells induced apoptosis of CD8(+) T cells to a greater degree (27.1+ or - 2.6%) compared with supernatants from CD133(-) cells (10.1 + or - 2.2%), and could be down-regulated by lactose, anti-galectin-3 polyclonal antibody and Gal-3 siRNA. Downregulation of Gal-3 resulted in significant inhibition of cancer cell growth in vitro.


CONCLUSIONS
Gal-3 is expressed at a relatively higher level in CD133(+) lung adenocarcinoma cells and could induce CD8(+) T cell apoptosis in vitro, both of which could be down-regulated by Gal-3 siRNA. These findings indicate that Gal-3 may play an important role during oncogenesis, implying a potential therapeutic target for pulmonary adenocarcinoma.
Department of Thoracis surgery, Union Hospital, Tongji medical college, Huazhong university of Science and Technology, Wuhan 430022, P.R.China.
Wan
W
Li
Wang
W
Jian-jun
Zhou
Z
Xue-Feng
Zhao
Z
Feng
D000071916:AC133 Antigen; D000230:Adenocarcinoma / Q000276:immunology*; D000328:Adult; D000368:Aged; D015703:Antigens, CD; D017209:Apoptosis / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D005260:Female; D037502:Galectin 3 / Q000235:genetics / Q000378:metabolism*; D006023:Glycoproteins; D006801:Humans; D018189:Immunomagnetic Separation; D008175:Lung Neoplasms / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010455:Peptides; D034741:RNA, Small Interfering / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection
D000071916:AC133 Antigen; D015703:Antigens, CD; D037502:Galectin 3; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; D034741:RNA, Small Interfering; D011994:Recombinant Proteins