Sloane B F, Rozhin J, Hatfield J S, Crissman J D, Honn K V
Department of Pharmacology, Wayne State University, Detroit, Mich.
Exp Cell Biol. 1987;55(4):209-24. doi: 10.1159/000163420.
The ability of tumor cells to invade into and through normal tissue during the metastatic cascade has been attributed to tumor-associated degradative enzymes including proteinases of the metallo, serine and cysteine classes. Work from several laboratories has established that the cysteine proteinases cathepsins L and B are released from tumor cells, primarily as latent precursor forms. In addition, a cathepsin B-like cysteine proteinase has been shown to be associated with the plasma membrane fraction of several animal and human tumors. This form of the enzyme retains activity under physiologic (or pathologic) conditions including at neutral pH and in the presence of low Mr inhibitors. Since we have established that cathepsin B can degrade the basement membrane attachment glycoprotein laminin, we speculate that plasma membrane-associated cathepsin B may participate in focal dissolution of the basement membrane during tumor cell extravasation.
在转移过程中，肿瘤细胞侵入并穿过正常组织的能力归因于肿瘤相关的降解酶，包括金属蛋白酶、丝氨酸蛋白酶和半胱氨酸蛋白酶。多个实验室的研究已证实，半胱氨酸蛋白酶组织蛋白酶L和B主要以无活性前体形式从肿瘤细胞中释放出来。此外，一种组织蛋白酶B样半胱氨酸蛋白酶已被证明与多种动物和人类肿瘤的质膜部分有关。这种形式的酶在生理（或病理）条件下，包括在中性pH值和存在低分子量抑制剂的情况下仍保持活性。由于我们已证实组织蛋白酶B可降解基底膜附着糖蛋白层粘连蛋白，因此我们推测质膜相关的组织蛋白酶B可能在肿瘤细胞外渗过程中参与基底膜的局部溶解。
