A soluble 17 kDa tumour necrosis factor (TNF) mutein, TNF-SAM2, with membrane-bound TNF-like biological characteristics.
BACKGROUND
Membrane-bound tumour necrosis factor (TNF) has a different binding affinity to two TNF receptors (TNFR1 and TNFR2) and shows different biological activities compared with TNF-alpha. We have developed a mutein, TNF-SAM2, which has modified TNF-alpha. It has higher tumour killing activity than TNF-alpha and fewer side effects.


METHODS
The difference between TNF-SAM2 and TNF-alpha was examined in view of the binding affinity to each TNF receptor, cytotoxicity and expression of genes using Colo205 cells.


RESULTS
The KD value of TNF-alpha (2. 9x1-7 M) for TNFR1 was lower than TNF-SAM2 (6.9x10(-7) M). Cytotoxicity of TNF-SAM2 was significantly higher than for TNF-a. RNA of Colo205 cells stimulated with TNF-SAM2 indicated that 80 genes increased by a factor of 2 or more, and 69 genes decreased.


CONCLUSIONS
TNF-SAM2 can induce different intracellular signal transduction in Colo205 cells compared with TNF-alpha. TNF-SAM2 may have characteristics of the membrane-bound form despite the fact that is in a soluble form.
Yoshida
Aya
A
Faculty of Engineering, The University of Tokushima, Tokushima-shi, Japan.
Kohchi
Chie
C
Inagawa
Hiroyuki
H
Nishizawa
Takashi
T
Hori
Hitoshi
H
Soma
Gen-Ichiro
G
D000230:Adenocarcinoma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism*; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000378:metabolism*; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism* / Q000494:pharmacology*
D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; C109083:TNF-SAM2; D014409:Tumor Necrosis Factor-alpha