ABSTRACT
Purpose To clarify the effect of adenosine on brain metastasis of lung cancer and the possible mechanism of adenosine promoting brain metastasis of lung cancer. Methods Western blot was used to dynamically detect the expression level of hypoxia inducible factor-1 (HIF-1) in lung cancer cells and tight junction protein ZO-1 in brain microvascular endothelial cells on blood-brain barrier. The content of adenosine in lung cancer cell culture was determined by ELISA. Fluorescence analysis was used to detect the changes of permeability of the blood-brain barrier model in vitro. Hemocytometer counts the number of A549 lung cancer cells in Transwell's lower chamber. Results The expression level of HIF-1 in lung cancer cells and the content of adenosine in lung cancer cell culture reached the highest level when lung cancer cells were deprived of oxygen for 12 hours. At the same time, the expression level of ZO-1 protein in the blood-brain barrier was the lowest, the blood-brain barrier permeability was the highest (7.11), and the number of lung cancer cells passing through the blood-brain barrier model was the highest (84.6). The permeability of the blood-brain barrier model increased after the action of adenosine, and its change trend was consistent with the effect of hypoxic lung cancer cell culture solution. Conclusion Hypoxia can induce the lung cancer cell to release adenosine, the increased adenosine can reduce the expression of tight junction protein ZO-1 in blood brain barrier, which leads to the increase of permeability of blood-brain barrier and eventually lead to brain metastasis of lung cancer.
ABSTRACT
<p><b>OBJECTIVE</b>Pelizaeus-Merzbacher disease (PMD) is a rare X-linked recessive leukoencephalopathy. Few reports of PMD patients without genetic confirmation have been published in the mainland of China. The clinical and genetic features of a family with PMD were analyzed, which may contribute to definite diagnosis, genetic counseling and prenatal diagnosis of this rare hereditary disease in China.</p><p><b>METHODS</b>Clinical data of the proband and other family members as well as 14 DNA samples were collected. Clinical features including symptoms, signs and cranial MRI were analyzed. Multiplex ligation-dependent probe amplification (MLPA) assays were performed to detect PLP1 duplication, which helps identify the type of PLP1 mutation in this family and the genotype-phenotype correlations.</p><p><b>RESULTS</b>(1) The proband and the other 3 male patients in the family presented with nystagmus, motor retardation followed by regression. The cranial MRI of proband showed evidence of poor myelination with diffused high signal in white matter region on T2-weighed image and reduced amount of white matter in volume, which is consistent with the typical features of cranial MRI in PMD. (2) PLP1duplication was identified in the proband. Combined with the clinical features of the proband and other patients in this family, the diagnosis of classic form of PMD was confirmed. Another 3 females with normal phenotype in the family were proved to be carriers of PLP1duplication.</p><p><b>CONCLUSIONS</b>(1) The Classic form of PMD in this pedigree is resulted from the PLP1 duplication, which is consistent with the previously reported genotype-phenotype correlations; (2) The results serve as an evidence for reliable genetic counseling and prenatal diagnosis for this family. (3) MLPA, which is a newly developed method, is a rapid and reliable technique to detect the whole gene duplication of PLP1.</p>