| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1998: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1997: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1996: ¥800,000 (Direct Cost: ¥800,000)
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| Research Abstract |
1. Association between chemosensitivity and apoptosis related protein expression
We studied immunohistochemical staining for the endoscopic biopsy specimens of the patients with gastric cancer treated with 5-FU+low dose cisplatin (FP) therapy. Among 18 patients with p53 positive (mutant type) carcinomas, 3 patients were responders of FP therapy. On the contrary, 10 of 12 patients with p53 negative tumors (wild type) showed the response to chemotherapy (P=0.04). The results suggested the patients with wild type p53 gastric carcinomas may be responders to FP therapy. Among the Bax-positive cases, the patients with Bc1-2-positive tumors were significantly more chemoresistant (P=0.036) and had worse prognosis (P=0.008) than Bc1-2-negative cases.
2. Association between chemosensitivity and interleukin 1-beta converting enzyme (ICE) activity in human gastric cancer cell line
It has been reported ICE may represent a final common pathway of apoptosis. We observed the peaks of ICE activities of ga
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stric cancer cell lines, OCUM-2M, OCUM-2M/DDP, Kato-III, and MKN-28 at 3hrs after exposure to cisplatin. The regression value was 0.66 between the IC_<50> to cisplatin and ICE activity ratio (ICE activity at 3hrs after exposure cisplatin/that of no treatment cells). It suggested ICE may be a predictor of chemosensitivity to cisplatin as a early response protein. Moreover, the significant lower levels of ICE activity and apoptotic index in the cisplatin resistant cell, OCUM-2M7DDP after exposure to cisplatin than those of its parent cell, OCUM-2M.The result indicated the relation between ICE activity and apoptosis.
3. p53 mutation site associated with chemosensitivity
p53 gene analyses were performed with SSCP and DNA direct sequencing for 8 gastrointestinal carcinomas treated with FP therapy. Foru of 6 responders (partial response) had wild type p53 gene whereas 2 non-responders (no change) had mutant p53 gene. A partial response tumor had point mutation at codon 259 of exon 7, while a no change tumor had 13bp deletion at codon 241-245 of exon 7. The result showed DNA direct se1quencing was required to identify p53 mutation site related with chemosensitivity. We analyzed p53 genes in other 22 gastrointestinal carcinomas which are treating with oral 5-FU derivatives. We are observing the prognosis of these patients as indicator of chemotherapeutic effect to accomplish the analysis of p53 mutation site associated with chemosensitivity. Less
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