Hyperthermia induces upregulation of connexin43 in the golden hamster neural tube.

BACKGROUND: During early embryonic development, maternal exposure to hyperthermia induces neural tube defects (NTDs). Connexins are essential for the formation of gap junctions and Connexin43 (Cx43) is crucially involved in neural tube development. This study was designed to explore the potential role of Cx43 in NTDs induced by hyperthermia. METHODS: Using PCR, the Cx43 cDNA was screened from the cDNA library of the neural tube from golden hamsters treated with hyperthermia. By Northern blot, the expression of Cx43 in heat-treated and control groups of the golden hamsters at day 8.5 after mating was detected. Finally, by in situ hybridization and RT-PCR, the expression of Cx43 was examined in the neural tube at different time points after heat treatment. RESULTS: Cx43 was stably expressed in heat-treated and control groups of the golden hamsters, whereas the expression was evidently higher in the heat-treated group. Cx43 expression in the neural tube at different time points after heat treatment was significantly higher than in control groups (p < 0.01). Hyperthermia did not induce any mutations in Cx43 cDNA. CONCLUSIONS: Our data provide the first evidence that hyperthermia induces upregulation of Cx43 in the golden hamster neural tube. NTDs caused by hyperthermia may be intimately related with the overexpression of Cx43.

[Significance and expression of vascular endothelial growth factor-C (VEGF-C) in esophageal squamous carcinoma and glioma].

BACKGROUND & OBJECTIVE: The research in recent years has demonstrated that vascular endothelial growth factor-C (VEGF-C) is expressed in certain malignant tumor cells, and up to now VEGF-C is the only growth factor specific for lymphangiogenesis. The relationship between the VEGF-C expression in malignant tumor tissues and lymphatic metastasis is still scarcely reported. This study was designed to compare the VEGF-C expression in human esophageal squamous carcinoma and glioma, and then to analyze the relationship between the VEGF-C expression and tumor lymphatic metastasis. METHODS: The expression of VEGF-C antigen was detected with immunohistochemical method in 72 human esophageal squamous carcinomas (29 cases with lymph node metastasis,43 cases without lymph node metastasis) and 23 human gliomas (diagnosed pathologically as astrocytoma in grades I to IV), followed by the further analysis on the relationship between VEGF-C expression and clinicopathological parameters. RESULTS: The expression of VEGF-C antigen was not found in any gliomas, while the positive VEGF-C expression rate achieved 38.88%(28/72) in the human squamous carcinoma, with 62.07%(18/29) in the cases with lymph node metastasis, 23.26%(10/43) in the cases without lymph node metastasis, 58.82% (20/34) in the T2 and T3 of invasion depth cases, and 21.05%(8/38)in the T1 of invasion depth cases. CONCLUSION: The expression of VEGF-C antigen was significantly associated with lymph node metastasis and invasion depth in esophageal squamous carcinoma. VEGF-C may act as a key factor in the facilitation of lymphatic metastasis in esophageal squamous carcinoma.