| Abstract |
In this study, a human undifferentiated carcinoma cell line of the
stomach, KKLS, was established for the purpose of elucidating the
biological characteristics of gastric undiferentiated carcinoma and of
developing a chemosensitivity test for clinical use. Tumor cells isolated
from the metastatic lymph node of a human gastric undifferentiated
carcinoma were grown in epithelioid form. KKLS-S cells were obtained from
a suspension of the primary culture and 3 clones by single cell cloning
from adherent cells. The doubling time ranged from 25 to 30 hrs and the
plating efficiencies varied from 8 to 22%. Chromosomal analysis revealed
translocation from 8q to 14p as a common abnormality. After
transplantation of KKLS-S cells into the nude mouse, a well circumscribed
solid tumor formed with similar histological features to the primary tumor.
Immunohistological and electron micrographic studies identified that they
descended from undifferentiated carcinoma. A chemosensitivity test using
3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay
revealed that KKLS-S cells were more sensitive to vindesine (VDS), and
etoposide (VP-16) than the other 3 gastric cancer cell lines. Out of
tested 10 drugs, carbazilquinone (CQ) was the most sensitive to KKLS-S
cells. This is the first report ever of a undifferentiated carcinoma cell
line of the stomach and it is expected to provide a good experimental
model for various investigations. Already one experimental model using
this cell line, a new chemosensitivity test, liquid top layer-MTT assay
(LMA) has been developed and examined. It is improvement of the MTT assay,
adapting the liquid top layer assay, for eliminating the effect of
fibroblasts. As far as the chemosensitivity of gastric cancer cell lines,
KKLS-S and 3 other additional lines, is concerned, the results of LMA had
a good correlation with those of the MTT assay. The growth of fibroblasts
was restrained by LMA, and the analysis of the inoculated tumor in the
nude mouse revealed that LMA was more reliable for primary culture than
the MTT assay. These studies suggest that the clinical use of LMA can be
expected to bring more accurate results because of the effect of
minimizing fibroblast production.
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