金沢大学がん研究所
PSP/reg蛋白に対する特異抗体を用いて確立したEIA法を用いて,血清および膵液中の本蛋白を測定し,その臨床的意義を検討した.血清中本蛋白は急性膵炎100%,慢性再発性膵炎59%に上昇がみられ,通常の慢性膵炎30%に比べて有意の高率であり,その異常率はelastase1よりも高率であった.膵炎発作後およびERCP後の血清中の本蛋白の推移はamylaseに比して,上昇の遷廷する傾向がみられた.また,膵癌54%,胃癌33%,肝細胞癌38%,胆道癌50%と癌患者血清でも上昇がみられ,癌切除後にいずれも明らかに低下した,同様の抗体を用いた免疫組織学的検討で軽度から中等度障害の慢性膵炎で本蛋白の発現は増加するが,高度障害では低下する傾向がみられた.また,胃癌,大腸癌,膵癌,胆道癌の組織でも本蛋白は50〜60%に発現していた.以上より,血清PSP/reg蛋白は膵炎で高頻度に上昇し,鋭敏な膵障害の指標にもなるものと考えられた.一方,膵液中のPSP/reg蛋白値は対照群、非石灰化慢性膵炎,石灰化慢性膵炎,膵癌の各群で明らからな差異はみられず,膵液中の本蛋白の測定には臨床的意義は認められなかった.消化器疾患でin situ hybridizationとRT-PCRにより,pancreatitis-associated protein (PAP) mRNAの検討を行った.PAPは小腸以外に正常では発現はみられないが,消化器系の癌ではかなりの頻度で発現していた.これは癌細胞の脱分化現象を反映した異所性発現と考えられた.ラットの自然発症慢性膵炎においてPAPの発現を検討したところ、慢性膵炎の病像を呈する前に本蛋白の発現がみられ,柴胡桂枝湯投与群では膵炎の変化は軽度で,PAPの発現は認められず,PAPの動態は慢性膵炎の早期発見や治療効果の指標になると思われた.PAPcDNAを組み込んだプラスミッドを大腸菌に導入し,PAPのりコンビナント蛋白の作製に成功した.今後,抗体を作製し,その臨床的応用をすすめる予定である.
We developed an enzyme-immunoassay using monoclonal antibody specific for pancreatic stone protein/reg-protein (PSP/reg), and determined levels of this protein in sera to elucidate the clinical significances of PSP/reg. Frequencies of elevated levels of serum PSP/reg were 100% in acute pancreatitis (AP) and 59% in chronic relapsing pancreatitis (CRP), and were significantly higher in active pancreatic injury such as AP or CRP than those in chronic pancreatitis (CP). Elevated serum levels of this protein after attack of pancreatitis of ERCP tended to be more prolonged than those of amylase. Furthermore, the serum PSP/reg levels were also significantly increased in various cancers of the digestive system (54% in pancreatic cancer (PC), 33% in gastric cancer, 38% in hepatocellular carcinoma and 50% in biliary cancer), and decreased into the normal range after tumor resection in all cases with cancers. The immunohistochemical study demonstrated increased amounts of PSP/reg in pancreatic tissues from patients with CP associated with mild-to-moderate pancreatic damage, and decreased expression in CP associated with severe pancreatic damage. Moreover, 50 to 60% of cancer tissues from the digestive system expressed the PSP/reg-protein in malignant cells, although this protein was absent from almost all of the adjacent non-cancerous tissues. These results indicate that the serum PSP/reg levels may reflect pancreatic damage, espcially in AP or presence of digestive cancer, and may be as sensitive a marker for such lesions. On the other hand, there was no significant differences in levels of PSP/reg in pancreatic juice among the groups of control, non-calcitying CP,calcifying CP and PC.The expression of pancreatitis-associated protein (PAP) belonging to reg-gene family was investigated in tissues from various digestive diseases, using in situ hybridization and RT-PCR.Although PAP-mRNA was not detected in normal tissues except for small intestine, PAP-mRNA was expressed in some cases of digestive cancers, suggesting an ectopic or oncofetal induction of PAP in differentiated cancer cells. The expression of PAP was observed in spontaneous occurring CP model (male WBN/Kob rat) before a characteristic picture of the CP appeared, and was not detectable in the rats treated by sho-saiko-to (TJ-9) which showed mild changes of pancreatitis. Therefore, the expression of PAP may be a marker for early detection or therapeutic effect in CP Moreover, we have succeeded in preparing recombinant of human PAP,and are producing monoclonal antibody to PAP to apply it to clinical applications.
研究課題/領域番号:07670578, 研究期間(年度):1995 – 1996
出典：研究課題「膵炎に関連する特異蛋白の病理生理的および臨床的意義の解明」課題番号07670578（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07670578/）を加工して作成