Chen B M, Chan L Y, Wang S M, Wu M F, Chern J W, Roffler S R
Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
Int J Cancer. 1997 Nov 4;73(3):392-402. doi: 10.1002/(sici)1097-0215(19971104)73:3<392::aid-ijc14>3.0.co;2-f.
We examined the in vivo efficacy of targeting beta-glucuronidase (betaG) to activate a glucuronide prodrug (BHAMG) of p-hydroxyaniline mustard (pHAM) at hepatoma ascites in Sprague-Dawley rats. Injection i.p. of 500 microg RH1-betaG, a conjugate formed between recombinant betaG and monoclonal antibody RH1 with specificity for an antigen expressed on AS-30D rat hepatoma cells, into rats bearing AS-30D ascites resulted in the accumulation of 54 microg conjugate per 10(9) tumor cells after 2 hr. Ascites fluid and serum contained 0.53 and 0 microg/ml, respectively, RH1-betaG 2 hr after injection of the conjugate. Conjugate binding to AS-30D cells was heterogeneous and non-saturated, as determined by flow cytometry. BHAMG was less toxic than pHAM to SD rats based on measures of animal mortality, weight loss and hematological toxicity. Treatment of rats bearing established hepatoma ascites with 500 microg RH1-betaG followed 2 hr later with a single i.p. injection of 30 mg/kg BHAMG or 3 i.p. injections of 10 mg/kg BHAMG 2, 3 and 4 hr later resulted in the cure of 6/8 and 8/8 animals, respectively. Treatment with BHAMG or pHAM alone did not produce cures, whereas treatment with a control antibody-betaG conjugate and BHAMG produced significantly greater hematological toxicity compared to treatment with RH1-betaG and BHAMG. All cured rats were completely protected from rechallenge with 2 x 10(7) AS-30D cells, indicating that successful treatment of animals induced protective immunity.
我们研究了在Sprague-Dawley大鼠肝癌腹水中，靶向β-葡萄糖醛酸酶（βG）以激活对羟基苯胺氮芥（pHAM）的葡萄糖醛酸苷前药（BHAMG）的体内疗效。向患有AS-30D腹水的大鼠腹腔注射500μg RH1-βG（一种重组βG与对AS-30D大鼠肝癌细胞上表达的抗原具有特异性的单克隆抗体RH1形成的偶联物），2小时后每10⁹个肿瘤细胞积累54μg偶联物。注射偶联物2小时后，腹水和血清中RH1-βG的含量分别为0.53和0μg/ml。通过流式细胞术测定，偶联物与AS-30D细胞的结合是异质性的且不饱和。基于动物死亡率、体重减轻和血液学毒性的测量，BHAMG对SD大鼠的毒性低于pHAM。用500μg RH1-βG治疗患有已形成肝癌腹水的大鼠，2小时后腹腔单次注射30mg/kg BHAMG或在2、3和4小时后腹腔注射3次10mg/kg BHAMG，分别使6/8和8/8的动物治愈。单独用BHAMG或pHAM治疗未产生治愈效果，而与用RH1-βG和BHAMG治疗相比，用对照抗体-βG偶联物和BHAMG治疗产生了明显更大的血液学毒性。所有治愈的大鼠都完全受到保护，免受2×10⁷个AS-30D细胞的再次攻击，这表明成功治疗动物可诱导保护性免疫。
