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Transforming activity of the RL‐ akt gene, a c‐ akt gene activated by long terminal repeat insertion in murine leukemia RL♂1 cells
Author(s) -
Tanino Motohiko,
Matsuo Mitsutoshi,
Uenaka Akiko,
Tsukuda Kazunori,
Ouchida Mamoru,
Nakayama Eiichi,
Shimizu Kenji
Publication year - 1999
Publication title -
molecular carcinogenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 97
eISSN - 1098-2744
pISSN - 0899-1987
DOI - 10.1002/(sici)1098-2744(199912)26:4<286::aid-mc7>3.0.co;2-u
Subject(s) - protein kinase b , biology , microbiology and biotechnology , 3t3 cells , pten , gene , cancer research , pi3k/akt/mtor pathway , phosphorylation , transfection , signal transduction , biochemistry
The unique antigen peptide pRL1 on BALB/c radiation‐induced leukemia RL♂1 cells is derived from the normally untranslated 5′ region of the mouse c‐ akt gene. Insertion of an endogenous long terminal repeat into the first coding exon of the gene resulted in the enhanced production of an altered akt protein, RL‐akt, and creation of the tumor rejection antigen peptide pRL1. In this study, we constructed an RL‐akt–expressing vector to investigate the transforming ability and anti‐apoptotic activity of RK‐akt in NIH/3T3 cells. RL‐akt–expressing clones formed more colonies than did c‐akt–expressing clones in soft agar and exhibited increased saturation density, a lower serum requirement for growth, and tumorigenicity on athymic nude mice. Immunoblot analysis of subcellular protein distribution showed that a considerable proportion of RL‐akt was distributed in the membrane fraction. Thus, RL‐akt expressed in NIH/3T3 cells appeared to behave like the v‐akt oncoprotein. Furthermore, the RL‐ akt gene conferred resistance to the apoptosis induced by the calcium ionophore A23187 and by ultraviolet irradiation of NIH/3T3 cells. These findings indicate that the RL‐ akt gene is able to transform cells and exerts an anti‐apoptotic effect on recipient cells, thereby implicating the gene in leukemogenesis of RL♂1 cells. Mol. Carcinog. 26:286–297, 1999. © 1999 Wiley‐Liss, Inc.