Cathepsin B and H activities and cystatin C concentrations in cerebrospinal fluid from patients with leptomeningeal metastasis.
BACKGROUND
Cysteine proteases are involved in the extension of cancer into the subarachnoid space. The presence of cathepsins B and H along with their potent inhibitor cystatin C in the cerebrospinal fluid (CSF) was investigated in patients with leptomeningeal metastasis of cancer (LM).


METHODS
CSF samples were obtained in 16 cases of LM (10 solid tumors and 6 leukemia or lymphoma) and compared with 11 cancer cases without involvement of the central nervous system, 12 multiple sclerosis cases and 34 healthy volunteers. The activity of the enzymes was measured, their molecular forms were analyzed by the Western blotting, and the concentration of cystatin C was measured by ELISA. Immunohistochemistry of the leptomeningeal tissues was also performed in six autopsy cases of LM.


RESULTS
High activities of cathepsins B and H along with decreased cystatin C concentration were observed in CSF of LM as compared with three control groups. Western blot analysis revealed higher concentration of the enzyme protein as well as its active forms in samples with higher enzyme activity. Cells metastasizing leptomeningeal tissue were clearly positive in immunohistochemical staining of cathepsins, indicating active production by tumor cells.


CONCLUSIONS
Production of cathepsins B and H by tumor cells and their high activity along with concomitant decrease of their potent inhibitor, cystatin C, in the CSF might contribute in the process of metastasis and spread of the cancer cells in the leptomeningeal tissues. A high enzyme activity/cystatin C concentration ratio in the CSF could be useful when diagnosing LM in combination with other parameters.
Nagai
Atsushi
A
Department of Internal Medicine III, Shimane Medical University, Izumo, Japan. anagai@shimane-med.ac.jp
Terashima
Masaharu
M
Harada
Takayuki
T
Shimode
Koichi
K
Takeuchi
Hiromi
H
Murakawa
Yohko
Y
Nagasaki
Makoto
M
Nakano
Akinobu
A
Kobayashi
Shotai
S
D015153:Blotting, Western; D002401:Cathepsin B / Q000134:cerebrospinal fluid*; D056655:Cathepsin H; D002403:Cathepsins / Q000134:cerebrospinal fluid*; D002452:Cell Count; D002555:Cerebrospinal Fluid / Q000166:cytology; D055316:Cystatin C; D015891:Cystatins / Q000134:cerebrospinal fluid*; D003546:Cysteine Endopeptidases / Q000134:cerebrospinal fluid*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007150:Immunohistochemistry; D007938:Leukemia / Q000473:pathology; D008577:Meningeal Neoplasms / Q000134:cerebrospinal fluid* / Q000473:pathology / Q000556:secondary*; D009362:Neoplasm Metastasis
C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D002403:Cathepsins; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; C534126:CTSH protein, human; D056655:Cathepsin H