Yoneda J, Saiki I, Fujii H, Abe F, Kojima Y, Azuma I
Institute of Immunological Science, Hokkaido University, Sapporo, Japan.
Clin Exp Metastasis. 1992 Jan;10(1):49-59. doi: 10.1007/BF00163576.
We have investigated the effect of the immunomodulator ubenimex (hereafter referred to as bestatin) on the enzymatic degradation of the extracellular matrix by human renal cell carcinoma SN12M cells during the invasive process. The invasion of SN12M cells into reconstituted basement membrane (Matrigel) was inhibited by the presence of bestatin in a concentration-dependent manner. However, bestatin did not have any effect on tumor cell adhesion and migration to the extracellular matrices which may be involved in tumor cell invasion. Bestatin inhibited the degradation of type IV collagen by tumor cells, but not by tumor-conditioned medium (TCM), in a concentration-dependent manner. We also found that bestatin inhibited hydrolysing activities towards substrates of aminopeptidases in SN12M cells. Since bestatin was found to inhibit aminopeptidase activity, the inhibition of tumor invasion by bestatin is likely to be associated with its action as an enzyme inhibitor. Bestatin only slightly inhibited tumor cell plasmin activity, which can lead to the conversion of the latent collagenase to the active form, but this slight effect was not significant. The zymography of TCM from SN12M cells showed that the treatment of tumor cells with bestatin resulted in the disappearance of the 68 kDa type IV collagenase-enzyme level (active form) and slight reduction of the 72 kDa type IV collagenase-enzyme level (latent form). These results indicated that bestatin may inhibit tumor cell invasion through a mechanism involving its inhibitory action on aminopeptidases in tumor cells, suggesting that the aminopeptidase may partly be associated with the conversion of a latent form of type IV procollagenase to an active form or the secretion of the collagenases from tumor cells.
我们研究了免疫调节剂ubenimex（以下简称贝司他汀）对人肾细胞癌SN12M细胞在侵袭过程中细胞外基质酶促降解的影响。贝司他汀的存在以浓度依赖性方式抑制了SN12M细胞向重组基底膜（基质胶）的侵袭。然而，贝司他汀对可能参与肿瘤细胞侵袭的肿瘤细胞与细胞外基质的黏附和迁移没有任何影响。贝司他汀以浓度依赖性方式抑制肿瘤细胞对IV型胶原的降解，但对肿瘤条件培养基（TCM）没有此作用。我们还发现贝司他汀抑制SN12M细胞中对氨肽酶底物的水解活性。由于发现贝司他汀可抑制氨肽酶活性，其对肿瘤侵袭的抑制作用可能与其作为酶抑制剂的作用有关。贝司他汀仅轻微抑制肿瘤细胞纤溶酶活性，纤溶酶可导致潜在胶原酶转化为活性形式，但这种轻微作用并不显著。SN12M细胞的TCM的酶谱分析表明，用贝司他汀处理肿瘤细胞会导致68 kDa IV型胶原酶水平（活性形式）消失，72 kDa IV型胶原酶水平（潜在形式）略有降低。这些结果表明，贝司他汀可能通过抑制肿瘤细胞中氨肽酶的作用来抑制肿瘤细胞侵袭，这表明氨肽酶可能部分与IV型前胶原酶潜在形式向活性形式的转化或肿瘤细胞中胶原酶的分泌有关。
