Alterations in erythrocyte membrane lipid and its fragility in a patient with familial lecithin : cholesterol acyltrasferase (LCAT) deficiency

Lecithin : cholesterol acyltrasferase (LCAT) plays a key role in the cholesterol metabolism-mediated esterification of free cholesterol into the cholesterol ester in normal plasma. Familial LCAT deficiency is frequently associated with anemia. Using biochemical and physiological techniques, the erythrocytes of this patient were investigated to gain an insight into the relationship between the abnormalities of lipid metabolism and erythrocyte membrane fragility. Abnormal erythrocytes, so-called Target cells and/or Knizocytes, were observed at 20% in our patient’s erythrocytes. Moreover, the mean corpuscular volume of the patient’s cells was 7% greater than that of a normal individual. In the membrane lipids of the patient’s erythrocytes, cholesterol and phosphatidylcholine increased, and phosphatidylethanolamine decreased. The electron spin resonance technique with a fatty acid spin probe showed that the membrane fluidity was more elevated than that of normal cells in spite of the increase in cholesterol content and the cholesterol/ phospholipid ratio of the membrane of patient’s erythrocytes. The patient’s abnormally shaped erythrocytes were less deformed than those of the normal individual under high shear stress. The partial depletion of membrane cholesterol from the patient’s erythrocytes was demonstrated by incubation with normal plasma with LCAT activity. The increment of transformed erythrocytes during the incubation could be prevented by cholesterol depletion from the patient’s erythrocyte membrane. These findings indicate that normochromic anemia of the patient might be caused by erythrocyte fragility resulting from decreased deformity and/or abnormal shape of the cells due to abnormal lipid composition in the membrane

Carrier cell-mediated cell lysis of squamous cell carcinoma by squamous cell carcinoma antigen 1 promoter-driven oncolytic adenovirus

The squamous cell carcinoma antigen (SCCA) serves as a serological marker for squamous cell carcinomas. Molecular cloning of the SCCA genomic region has revealed the presence of two tandemly arrayed genes, SCCA1 and SCCA2. We examined the promoter activity of the 5'-flanking proximal region of the SCCA1 gene. Deletion analysis of SCCA1 promoter identified a 175-bp core promoter region and an enhancer region at -525 to -475 bp upstream of the transcription start site. The transcriptional activity of the SCCA1 promoter was up-regulated in squamous cell carcinoma cells, compared with normal keratinocyte, normal non-keratinocyte and adenocarcinoma cells. Five tandem repeats of enhancer increased SCCA1 promoter activity by 4-fold. Oncolytic adenovirus driven by the SCCA1 promoter with 5 tandem repeats of enhancer specifically killed squamous cell carcinoma cells in vitro and in vivo. A549 carrier cells infected with the oncolytic adenovirus induced complete regression of tumor by overcoming immunogenicity and adenovirus-mGM-CSF augmented the antitumor effect of carrier cells. These findings suggest that SCCA1 promoter is a potential target of gene therapy for squamous cell carcinoma