Heidtmann H H, Salge U, Abrahamson M, Bencina M, Kastelic L, Kopitar-Jerala N, Turk V, Lah T T
Department of Haematology, Oncology and Clinical Immunology, Philipps University, Marburg, Germany.
Clin Exp Metastasis. 1997 Jul;15(4):368-81. doi: 10.1023/a:1018494020001.
Cell lines derived from human squamous cell (EPCL), large cell (LCLC), and small cell lung cancer (SCLC) lines were investigated for the expression of cathepsin B (Cat B) and cysteine proteinase inhibitors (CPIs). The EPLC and LCLC lines expressed 5- to 50-fold more Cat B activity and contained more mature Cat B of M(r) 27-29 kDa (> 2.5 microg/mg total protein) than the SCLC lines (< 1.0 microg/mg total protein). The LPLC lines also secreted the highest amounts of Cat B precursor of M(r) about 46 kDa. Inhibitory activities against Cat B and papain were associated with high molecular mass (HMM) and low molecular mass (LMM) inhibitory proteins, both in cell extracts and in media. About 75% of the inhibitory activity was associated with HMM inhibitors, the majority of which were kininogens (M(r) > or = 67 kDa). The LMM inhibitors of M(r) 10-15 kDa were cystatin C and stefins A and B, which were quantitated by ELISA: stefins A and B were present in cell extracts and medium in similar concentrations (5-200 ng/10(6) cells), while 80-99% of the cystatin C was released in the medium (10-195 ng/10(6) cells). Phorbol ester (PMA), which induces protein-kinase C mediated signal transduction and enhances cellular differentiation in many non-small cell lung cancer (NSCLC) cell lines, increased intracellular Cat B activity and Cat B protein as well as its secretion in some cell lines but not in others, regardless of their histological type. PMA significantly (P < 0.049) decreased intracellular stefin A concentrations in two EPLC lines and non-significantly in two LCLC lines. PMA decreased secretion of stefin A in all EPLC lines, but not in LCLC lines, while IGF-I significantly increased stefin B secretion in both SCLC lines. These data showed that lung tumor cells produce both cysteine proteinases and cystatins. As the antagonistic molecules are regulated differently in histologically different types of lung tumor cells, it is possible that an imbalance between the proteinases and their specific inhibitors plays a role in progression of certain types of lung tumors in vivo.
对源自人鳞状细胞（EPCL）、大细胞（LCLC）和小细胞肺癌（SCLC）系的细胞系进行组织蛋白酶B（Cat B）和半胱氨酸蛋白酶抑制剂（CPIs）表达情况的研究。与SCLC系（总蛋白中<1.0μg/mg）相比，EPLC和LCLC系的Cat B活性高5至50倍，且含有更多M(r) 27 - 29 kDa的成熟Cat B（>2.5μg/mg总蛋白）。LPLC系还分泌最多量的M(r)约46 kDa的Cat B前体。在细胞提取物和培养基中，针对Cat B和木瓜蛋白酶的抑制活性与高分子量（HMM）和低分子量（LMM）抑制蛋白有关。约75%的抑制活性与HMM抑制剂有关，其中大多数是激肽原（M(r)≥67 kDa）。M(r) 10 - 15 kDa的LMM抑制剂是胱抑素C以及丝抑素A和B，通过酶联免疫吸附测定法进行定量：丝抑素A和B在细胞提取物和培养基中的浓度相似（5 - 200 ng/10⁶个细胞），而80 - 99%的胱抑素C释放到培养基中（10 - 195 ng/10⁶个细胞）。佛波酯（PMA）可诱导蛋白激酶C介导的信号转导，并增强许多非小细胞肺癌（NSCLC）细胞系的细胞分化，它能增加某些细胞系而非其他细胞系的细胞内Cat B活性、Cat B蛋白及其分泌，无论其组织学类型如何。PMA使两个EPLC系的细胞内丝抑素A浓度显著降低（P<0.049），使两个LCLC系的细胞内丝抑素A浓度降低但不显著。PMA使所有EPLC系的丝抑素A分泌减少，但不影响LCLC系，而胰岛素样生长因子I（IGF - I）显著增加两个SCLC系的丝抑素B分泌。这些数据表明，肺肿瘤细胞可产生半胱氨酸蛋白酶和胱抑素。由于在组织学不同类型的肺肿瘤细胞中，这些拮抗分子的调节方式不同，蛋白酶及其特异性抑制剂之间的失衡可能在体内某些类型肺肿瘤的进展中起作用。
