LOCALIZATION OF CATHEPSIN-B IN 2 HUMAN LUNG-CANCER CELL-LINES
LOCALIZATION OF CATHEPSIN-B IN 2 HUMAN LUNG-CANCER CELL-LINES
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DOI:
10.1177/38.9.2201737
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发表时间:
1990-09-01
影响因子:
3.2
通讯作者:
EBERT, W
中科院分区:
文献类型:
--
作者:
ERDEL, M;TREFZ, G;EBERT, W
We demonstrated the cysteine proteinase cathepsin B in two human lung tumor cell lines by cytochemical and immunocytochemical methods. The cell lines were derived from a squamous cell carcinoma of the lung (HS-24) and a metastastis to the adrenal gland from an adenocarcinoma of the lung (SB-3). For comparison and control, normal human lung fibroblast cells (Wi-38) were also investigated. Intracellular cathepsin B activity was detected in all three cell lines. SB-3 and the normal fibroblast cells showed almost equal cathepsin B activity, which was considerably stronger than that in the HS-24 cells. Specific inhibitors for cathepsin B (E64, leupeptin, antipain) suppressed its activity completely. Stefin A, the physiological cathepsin B inhibitor, was less effective; this might depend on its limited penetrability into living cells. Localization of the cathepsin B was performed by conventional immunofluorescence microscopy and laser scanning microscopy. With specific anti-cathepsin B antibodies, the enzyme was localized in HS-24, SB-3, and Wi-38 fibroblast cells within perinuclear granules representing the lyosomal compartment. In the SB-3 cells, we additionally localized a minor fraction of the enzyme bound to the plasma membrane in a speckled distribution, accessible to the antibodies from the outside. This direct demonstration of cathepsin B distribution supports biochemical data about the dual localization of the enzyme in tumor cells. It also supports the possibility of a direct involvement of cathepsin B in the degradation of the extracellular matrix, and thus a contribution of the enzyme in invasion and metastasis.