ヒト正常および癌化した肺組織における血液型抗原とポリ-N-アセチルラクトサミンおよびケラタン硫酸の局在

Abstract

Poly-N-acetyllactosaminyl structures are considered to be patho- physiologically important carbohydrate antigens, and to play important roles in not only cell differentiation, malignant transformation, and cancer metastasis but also blood group ABO antigens. The aim of the present study was to investigate the stainability of human lung cancer tissues by using 6 lectins (PWM, PFA, LEA, STA, DSA, and Suc-WGA) which have specificity for poly-N-acetyl lactosaminyl structures, monoclonal 5-D-4 antibody which strongly reacts with keratan sulfate, and monoclonal anti-A and anti-B antibodies. In normal human lung tissues, alveolar epithelium cells and ciliated cells of bronchiole were positively stained by each lectin. In lung cancer tissues, well and moderate- ly differentiated adenocarcinomas and some well-differentiated squamous cell carcinomas were stained by the lectins in cancer cell membranes and cytoplasms. However, low grade adenocarcinomas, low and moderate grade squamous cell carcinomas, and small and large cell carcinomas were not stained. Neuraminidase enzyme digestion strongly stained normal lung alveolar epithelim cells, but not well-differentiated adenocarCinomas. 5-D-4 antibody stained cell membrane and cytoplasm in some well-differentiated adenocarcinomas. UEA-1 lectin and monoclonal anti-A and anti-B antibodies stained alveolar epithelium cells in normal tissues, cell membrane and cytoplasm in well and moderately differentiated adenocarcinomas, and well and moderately differentiated squamous cell carcinomas. The stainability was consistent with the ABO blood groups of each individual. From these results, normal lung tissues have poly-N-acetyllactosaminyl structures coated by sialic acid with linear unbranched short and long sequences and highly branched sequences. However, well-differentiated adenocarcinomas and squamous cell carcinomas were consid- ered to have poly-N-acetyllactosaminyl structures not coated by sialic acid. Also, it was suggested that some well-differentiated adenocarcinomas have keratan sulfate epitopes, and that well-differentiated adenocarcinomas and squamous cell carcinomas have blood group antigens. The authors conclude that well-differentiated adenocarcinomas and squamous cell carcinomas have poly-N-acetyllactosaminyl structures with keratan sulfate epitopes and that the structure is involved in blood group antigens.