Trerè D, Fiume L, De Giorgi L B, Di Stefano G, Migaldi M, Derenzini M
Servizio di Citopatologia, Policlinico S Orsola, and Dipartimento di Patologia Sperimentale, Università di Bologna, Italy.
Br J Cancer. 1999 Oct;81(3):404-8. doi: 10.1038/sj.bjc.6690708.
The expression of the asialoglycoprotein receptor (ASGP-R) on human hepatocellular carcinoma (HCC) cells might be exploited to reduce the extrahepatic toxicity of DNA synthesis inhibitors by their conjugation with galactosyl-terminating peptides. In the present study we first assessed the frequency of ASGP-R expression in 60 HCCs. Secondly, we investigated whether the receptor was maintained on the plasma membranes of DNA synthesizing cancer cells. Needle biopsies of HCC were evaluated. Diagnosis and grading of HCC were performed on routine haematoxylin and eosin-stained sections according to Edmondson and Steiner (1953). Thirty-five tumours were grade I and II and were classified as well differentiated, while 25 tumours were grade III and IV and were classified as poorly differentiated. Sections from formalin-fixed, paraffin-embedded samples were incubated, after antigen retrieval, with an anti-ASGP-R monoclonal antibody revealed by secondary biotinylated antibody and streptavidin-biotin-peroxidase-diaminobenzidine reaction. A clear immunolabelling of plasma membranes of HCC cells was observed in 28 out of 35 (80%) well differentiated (grade I and II) and in five out of 25 (20%) poorly differentiated (grade III and IV) HCCs. The presence of the ASGP-R on the surface of DNA synthesizing cancer cells was also investigated after in vitro bromodeoxyuridine (BrdU) labelling of HCC samples by immunohistochemical visualization of both the ASGP-R and incorporated BrdU on the same section. The results obtained clearly demonstrated that DNA synthesizing cancer cells expressed the ASGP-R on their surface. The presence of ASGP-R on cell plasma membrane in the majority of differentiated HCCs and its maintenance on proliferating cells encourages studies in order to restrict the action of the inhibitors of DNA synthesis of HCC cells by their conjugation with galactosyl-terminating carriers internalized through this receptor.
人肝细胞癌（HCC）细胞上无唾液酸糖蛋白受体（ASGP-R）的表达，或许可通过将DNA合成抑制剂与半乳糖基末端肽结合，来降低其肝外毒性。在本研究中，我们首先评估了60例HCC中ASGP-R表达的频率。其次，我们研究了该受体是否在DNA合成癌细胞的质膜上得以保留。对HCC进行针吸活检并评估。根据Edmondson和Steiner（1953年）的标准，在常规苏木精和伊红染色切片上对HCC进行诊断和分级。35例肿瘤为I级和II级，归类为高分化，而25例肿瘤为III级和IV级，归类为低分化。经抗原修复后，用抗ASGP-R单克隆抗体孵育福尔马林固定、石蜡包埋样本的切片，通过生物素化二抗和链霉亲和素-生物素-过氧化物酶-二氨基联苯胺反应显示结果。在35例高分化（I级和II级）HCC中有28例（80%）观察到HCC细胞质膜有清晰的免疫标记，在25例低分化（III级和IV级）HCC中有5例（20%）观察到。在体外对HCC样本进行溴脱氧尿苷（BrdU）标记后，通过在同一切片上对ASGP-R和掺入的BrdU进行免疫组化可视化，还研究了DNA合成癌细胞表面ASGP-R的存在情况。所获结果清楚地表明，DNA合成癌细胞在其表面表达ASGP-R。大多数分化型HCC细胞质膜上存在ASGP-R且其在增殖细胞上得以保留，这鼓励开展研究，以便通过将HCC细胞DNA合成抑制剂与通过该受体内化的半乳糖基末端载体结合，来限制其作用。
