Watanabe N, Yamauchi N, Neda H, Maeda M, Tsuji Y, Okamoto T, Akiyama S, Sasaki H, Tsuji N, Niitsu Y
Department of Internal Medicine, Sapporo Medical College.
Jpn J Cancer Res. 1992 Jun;83(6):638-43. doi: 10.1111/j.1349-7006.1992.tb00137.x.
We investigated the effect of recombinant human tumor necrosis factor (TNF) on the lysosomal enzyme activity of various established cell lines in vitro. Incubation of 1 x 10(6) TNF-sensitive mouse tumorigenic fibroblasts (L-M cells) in the presence of TNF (100 U/ml) for 48 h increased the total (the sum of the enzyme activities in the lysosomes and the cytoplasm) acid phosphatase and beta-glucuronidase activities by 3.7- and 4.2-fold, respectively. The same increase was observed even when 1 U/ml of TNF was added to some cultures and no further augmentation occurred at 10 or 100 U/ml. Measurement of total and free enzyme activities showed that TNF stimulation not only enhanced the total intracellular enzyme activity but also accelerated the conversion into free (cytoplasmic) enzyme activity. Addition of a lysosomotropic agent (methylamine) suppressed both the enhancement of lysosomal enzyme activity and the cytotoxicity of TNF. A similar enhancement of lysosomal enzyme activities was also detected in various TNF-sensitive tumor cell lines, and a strong correlation (acid phosphatase: r = 0.836, beta-glucuronidase: r = 0.910) was observed between the enhancement of enzyme activity and sensitivity to TNF. No such increase was detected in TNF-resistant human diploid cells. These results show that TNF induces the activation and release of lysosomal enzymes in TNF-sensitive cells, and suggest that such events may play an important role in TNF-mediated cytotoxicity.
我们在体外研究了重组人肿瘤坏死因子（TNF）对各种已建立细胞系溶酶体酶活性的影响。在TNF（100 U/ml）存在的情况下，将1×10⁶个对TNF敏感的小鼠致瘤性成纤维细胞（L-M细胞）孵育48小时，总酸性磷酸酶（溶酶体和细胞质中酶活性之和）和β-葡萄糖醛酸酶活性分别增加了3.7倍和4.2倍。即使在一些培养物中加入1 U/ml的TNF也观察到相同程度的增加，而在10或100 U/ml时没有进一步增强。对总酶活性和游离酶活性的测量表明，TNF刺激不仅增强了细胞内总酶活性，还加速了其向游离（细胞质）酶活性的转化。添加溶酶体促渗剂（甲胺）可抑制溶酶体酶活性的增强以及TNF的细胞毒性。在各种对TNF敏感的肿瘤细胞系中也检测到了溶酶体酶活性的类似增强，并且在酶活性增强与对TNF的敏感性之间观察到了很强的相关性（酸性磷酸酶：r = 0.836，β-葡萄糖醛酸酶：r = 0.910）。在对TNF耐药的人二倍体细胞中未检测到这种增加。这些结果表明，TNF诱导对TNF敏感的细胞中溶酶体酶的激活和释放，并提示这些事件可能在TNF介导的细胞毒性中起重要作用。
