A modified version of galectin-9 suppresses cell growth and induces apoptosis of human T-cell leukemia virus type I-infected T-cell lines.
ATL is a fatal malignancy of T lymphocytes caused by HTLV-I infection and remains incurable. Galectins are a family of animal lectins that function both extracellularly (by interacting with cell surface and extracellular matrix glycoproteins and glycolipids) and intracellularly (by interacting with cytoplasmic and nuclear proteins) to modulate signaling pathways. We found that protease-resistant galectin-9 by modification of its linker peptide, hG9NC(null), prevented cell growth of HTLV-I-infected T-cell lines and primary ATL cells. The suppression of cell growth was inhibited by lactose, but not by sucrose, indicating that beta-galactoside binding is essential for hG9NC(null)-induced cell growth suppression. hG9NC(null) induced cell cycle arrest by reducing the expression of cyclin D1, cyclin D2, cyclin B1, Cdk1, Cdk4, Cdk6, Cdc25C and c-Myc, and apoptosis by reducing the expression of XIAP, c-IAP2 and survivin. Most of these genes are regulated by NF-kappaB, which plays a critical role in oncogenesis by HTLV-I. hG9NC(null) suppressed IkappaBalpha phosphorylation, resulting in suppression of NF-kappaB. Most importantly, treatment with hG9NC(null) (6.7 mg/kg injected intraperitoneally every day) reduced tumor formation from an HTLV-I-infected T-cell line when these cells were inoculated subcutaneously into SCID mice. Our results suggest that hG9NC(null) could be a suitable agent for the management of ATL.
Okudaira
Taeko
T
Division of Molecular Virology and Oncology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan.
Hirashima
Mitsuomi
M
Ishikawa
Chie
C
Makishi
Shoko
S
Tomita
Mariko
M
Matsuda
Takehiro
T
Kawakami
Hirochika
H
Taira
Naoya
N
Ohshiro
Kazuiku
K
Masuda
Masato
M
Takasu
Nobuyuki
N
Mori
Naoki
N
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D005260:Female; D005697:Galactosides / Q000378:metabolism; D037161:Galectins / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology*; D006131:Growth Inhibitors / Q000494:pharmacology; D015490:HTLV-I Infections / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology; D000072597:Hepatitis A Virus Cellular Receptor 2; D015368:Human T-lymphotropic virus 1 / Q000254:growth & development*; D006801:Humans; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D008565:Membrane Proteins; D051379:Mice; D016513:Mice, SCID; D016328:NF-kappa B / Q000235:genetics / Q000276:immunology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011991:Receptors, Virus / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000276:immunology / Q000473:pathology* / Q000821:virology*; D001616:beta-Galactosidase / Q000378:metabolism
D005697:Galactosides; D037161:Galectins; D006131:Growth Inhibitors; C448908:HAVCR2 protein, human; D000072597:Hepatitis A Virus Cellular Receptor 2; C091991:LGALS8 protein, human; C105032:LGALS9 protein, human; D008565:Membrane Proteins; D016328:NF-kappa B; D012333:RNA, Messenger; D011991:Receptors, Virus; C007816:beta-galactoside; D001616:beta-Galactosidase; D020169:Caspases