McCaughan G W, Siah C L, Abbott C, Wickson J, Ballesteros M, Bishop G A
A. W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.
J Gastroenterol Hepatol. 1993 Mar-Apr;8(2):142-5. doi: 10.1111/j.1440-1746.1993.tb01505.x.
Dipeptidyl peptidase IV (DPP-IV) is a cell surface ectopeptidase that has been implicated in cell-extracellular matrix interactions, lymphocyte growth and the regulation of biological peptides. Previous studies have shown that immunostaining for DPP-IV and DPP-IV enzyme levels is decreased in hepatoma cells and levels have been correlated with the ability of such cells to adhere in vitro. The aim of this paper was to measure DPP-IV enzyme levels in rat hepatoma cells and to examine whether changes were associated with alterations at the mRNA level. The results indicate a greater than 90% reduction in DPP-IV enzyme levels in two rat hepatoma cell lines, HTC and H35, compared with rat hepatocytes. Enzyme levels of the control enzyme leucine aminopeptidase (LAP) were not decreased. mRNA studies indicated that these changes were associated with similar reductions in rat DPP-IV mRNA. It is concluded that DPP-IV is markedly reduced at the protein, enzyme and mRNA levels in rat hepatoma cells. The significance of these changes is unclear but may lead to decreased extracellular matrix interactions by such cells.
二肽基肽酶IV（DPP-IV）是一种细胞表面外肽酶，它与细胞-细胞外基质相互作用、淋巴细胞生长以及生物肽的调节有关。先前的研究表明，肝癌细胞中DPP-IV的免疫染色和DPP-IV酶水平降低，且这些水平与此类细胞在体外的黏附能力相关。本文的目的是测量大鼠肝癌细胞中的DPP-IV酶水平，并检查这些变化是否与mRNA水平的改变有关。结果表明，与大鼠肝细胞相比，两种大鼠肝癌细胞系HTC和H35中的DPP-IV酶水平降低了90%以上。对照酶亮氨酸氨肽酶（LAP）的酶水平没有降低。mRNA研究表明，这些变化与大鼠DPP-IV mRNA的类似减少有关。结论是，大鼠肝癌细胞中DPP-IV在蛋白质、酶和mRNA水平上均显著降低。这些变化的意义尚不清楚，但可能导致此类细胞与细胞外基质的相互作用减少。
