Mori M, Yamaguchi K, Honda S, Nagasaki K, Ueda M, Abe O, Abe K
Growth Factor Division, National Cancer Center Research Institute, Tokyo, Japan.
Cancer Res. 1991 Dec 15;51(24):6656-9.
Melanoma-derived lipoprotein lipase inhibitor (MLPLI) is a factor purified from the conditioned medium of a human melanoma cell line, SEKI, which induced severe cachexia in tumor-bearing nude mice. Amino acid sequencing revealed that the amino-terminal portion was identical to that of leukemia-inhibitory factor (LIF). To determine whether MLPLI is actually LIF, the expression of LIF mRNA was examined in the SEKI melanoma cell line. Northern blot analyses revealed that the cell line displayed an intense hybridizable band with a molecular size of 3.8 kilobases, suggesting that MLPLI is identical to LIF. The relationship between the development of the cancer cachexia syndrome and the expression of LIF mRNA was examined in four melanoma xenografts, SEKI, G361, A375 and MEWO, in nude mice. SEKI- and G361-bearing nude mice developed cancer cachexia syndrome, and their body weights decreased by the 25th day after the transplantation to 73.6% and 73.8% of the control, respectively. A375- and MEWO-bearing nude mice, however, did not develop the syndrome. Northern blot analyses revealed that G361 as well as SEKI expressed a large amount of LIF mRNA, but A375 and MEWO did not, suggesting a close relationship between the expression of LIF mRNA and the development of the syndrome. These data support the concept that MLPLI, or LIF, plays an important role in the development of the cancer cachexia syndrome observed in melanoma-bearing nude mice.
黑色素瘤衍生的脂蛋白脂肪酶抑制剂（MLPLI）是一种从人黑色素瘤细胞系SEKI的条件培养基中纯化得到的因子，它能在荷瘤裸鼠中诱发严重的恶病质。氨基酸测序显示其氨基末端部分与白血病抑制因子（LIF）相同。为了确定MLPLI是否实际上就是LIF，在SEKI黑色素瘤细胞系中检测了LIF mRNA的表达。Northern印迹分析显示该细胞系呈现出一条分子大小为3.8千碱基的强烈杂交带，表明MLPLI与LIF相同。在裸鼠的四种黑色素瘤异种移植模型SEKI、G361、A375和MEWO中研究了癌症恶病质综合征的发生与LIF mRNA表达之间的关系。携带SEKI和G361的裸鼠出现了癌症恶病质综合征，移植后第25天时它们的体重分别降至对照组的73.6%和73.8%。然而，携带A375和MEWO的裸鼠并未出现该综合征。Northern印迹分析显示G361以及SEKI表达大量的LIF mRNA，但A375和MEWO不表达，这表明LIF mRNA的表达与该综合征的发生密切相关。这些数据支持了MLPLI或LIF在荷黑色素瘤裸鼠中观察到的癌症恶病质综合征的发生中起重要作用这一概念。
