RESUMEN
OBJECTIVE: To study the relationship between hypoxia and the hypoxia inducible factor-1α (HIF-1α) from lung cancer cells, to reveal the possible mechanism of brain metastases of lung cancer. METHODS: The hypoxia model of A549 lung cancer cells was established. After hypoxia culture of A549 cells for 0.5, 2, 4, 8, 12 and 24 h (normal oxygen culture at the same time point was set as the control group), the mass concentration of HIF-1α in A549 lung cancer cell culture medium were determined by ELISA. Transwell chamber was used to construct an in vitro blood brain barrier model, was treated with A549 lung cancer cell culture medium after different time points of hypoxia, Tran endothelial resistance (TER) change of blood-brain barrier model in instrument, to reflect the changes of blood-brain barrier permeability in vitro; A549 lung cancer cells in the culture medium were counted under Transwell room. A549 lung cancer cells with hypoxia at different time points injected into Wistar rats via tail vein, Western blot method was used to menstruate expression of tight junction associated protein Claudin-5 in the brain tissues, Evans blue to detect the change of blood brain barrier permeability in rats. RESULTS: Compared with the control group, the HIF-1α mass concentration in the cell culture solution of A549 increased, the in vitro blood-brain barrier model TER decreased, and the cell number of A549 that passed through transwell into the lower chamber increased (all P<0.05) after hypoxia 2 h, the above effect was most obvious when hypoxia 8 h (all P<0.01). After hypoxia 24 h, it was restored to the control group level. In the in vivo experiment of rats, compared with the control group, the mass percent of Evans blue in rat brain tissues increased after A549 cell culture solution with hypoxia 2 h was injected via caudal vein, meaning increased the permeability of rat blood brain barrier, while the expression of Claudin-5 protein in rat brain tissues decreased (all P<0.05). The effect was most obvious when A549 cell culture solution with hypoxia 8 h was injected into rat tail vein (P<0.01 ). Ejectionof hypoxia 24 h A549 cell culture solution yielded the same effects as those in the control group. CONCLUSION: Hypoxia can induce the increase of HIF-1α in lung cancer cells. The increase of HIF-1α results in the decrease of Claudin-5 expression and increase of blood-brain barrier permeability, leading to lung cancer cells metastasis into the brain.
Asunto(s)
Neoplasias Encefálicas/secundario , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Neoplasias Pulmonares/patología , Células A549 , Animales , Hipoxia de la Célula , Humanos , Trasplante de Neoplasias , Ratas , Ratas WistarRESUMEN
OBJECTIVE: To determine the effect of prostaglandin E2 (PGE2) on brain metastasis of lung cancer,and to explore the possible mechanism of aspirin (PGE2 inhibitor) reducing brain metastasis of lung cancer. METHODS: Radioimmunoassay was performed to measure the expression level of PGE2 in cell supernatant collected from cells treated with or without aspirin (8 mmol/L) at different time points. After establishing in vitro blood-brain barrier (BBB) model using Transwell, lung cancer cells was added to upper chamber of transwell and was then treated with aspirin (8 mmol/L). Western blot was used to examine the expression of occludin protein in brain microvascular endothelial cells. The permeability changes of BBB model in vitro were determined using horseradish peroxides. The number of lung cancer cells passing through BBB model in vitro was counted with Hemocytometer. Effect of aspirin on brain metastasis of lung cancer was observed in nude mice in the animal level. RESULTS: PGE2 level decreased and reached minimum level 120 min after aspirin treatment in lung cancer cells culture fluid. Occludin expression increased and reached maximum level 120 min after aspirin treatment in brain microvascular endothelial cells. At the same time,permeability of BBB and number of lung cancer cells passing through BBB also reached the lowest value 120 min after aspirin treatment. Aspirin significantly reduced the incidence of brain metastasis of lung cancer in animal model. CONCLUSION: Aspirin reduced occurrences of the brain metastasis of lung cancer in animal model,which may be caused by inhibition of PGE2 released by lung cancer cells and upregulation of occludin expression therefore leading to decrease in BBB permeability.
Asunto(s)
Aspirina/farmacología , Barrera Hematoencefálica/efectos de los fármacos , Neoplasias Pulmonares/patología , Metástasis de la Neoplasia , Ocludina/metabolismo , Animales , Encéfalo , Neoplasias Encefálicas/secundario , Dinoprostona/antagonistas & inhibidores , Ratones , Ratones DesnudosRESUMEN
OBJECTIVE: 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. METHODS: 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. RESULTS: (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. CONCLUSIONS: (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.