Mutation of the p53 tumor suppressor gene is recognized to be a key event in the development of the highly aggressive behavior of undifferentiated or anaplastic thyroid carcinomas. Attempts to treat these carcinomas with p53 gene therapy have, however, been largely unsuccessful. Since epigenetic changes such as histone deacetylation are associated with loss of thyroid differentiation, we have evaluated the potential of combining p53 gene therapy with exposure to the histone deacetylase inhibitor (HDAC-1), depsipeptide. We used two carcinoma cell lines: FRO cells that express very low levels of p53 and WRO cells producing a dominant negative p53. A p53 response element luciferase assay showed that stimulation of p53 transcriptional activity by the combined treatment with the HDAC-1 and p53 was 10 to 100 times greater than with p53 alone. Western blot analysis demonstrated that the HDAC-1 increased the expression of acetylated histones, as well as of p21(cip1/waf1), but did not affect levels of total histone and endogenous p53. The combined treatment was much more effective than either treatment alone in inhibiting the growth of both cell lines, and flow cytometric analysis suggested that this was due to an increase in the sub-G1 apoptotic population. Our findings indicate that HDAC-1 enhances apoptotic killing by p53 transfer, and suggest that this combination strategy may be useful in treating undifferentiated thyroid carcinomas.

Cervical aortic arch is an unusual malformation. Cervical aortic arch with aneurysm formation is very rare. We report a case of cervical aortic arch associated with a saccular aneurysm in a 59-year-old Japanese man. The aneurysm protruded caudally and was located between the left common carotid and left subclavian arteries. Cardiopulmonary bypass and deep hypothermic circulatory arrest was applied as adjunct methods. A Dacron graft was sutured just distal to the left common carotid artery, with the patient in the Trendelenburg position. The proximal site was left open while oxygen-saturated venous blood was supplied in a retrograde manner to perfuse the lower body during occlusion of the descending aorta. Distal anastomosis to the descending aorta was performed during rewarming. The left subclavian artery was reconstructed by using a branch of the graft. This procedure is simple and useful for distal arch operations, especially in patients with Haughton D type aneurysms.

The prognosis of patients with metastatic gastric cancer, particularly peritoneal carcinomatosis, remains poor despite intensive interventions. Gene therapy and hyperthermia can be promising strategies for such advanced disease. The study was conducted to explore the possible effective therapeutic approach of suicide gene therapy with herpes simplex virus thymidine kinase (HSV-tk) in combination with hyperthermia for advanced gastric cancer. The heat shock protein (hsp) 70B gene promoter-oriented HSV-tk (HSP-tk)/ganciclovir (GCV) system directed by heat shock was developed. Hsp promoter activity under the control of heating was assessed by dual luciferase assay in gastric cancer cell lines and implanted tumors of nude mice. In vitro cytotoxic assay was performed using the HSP-tk/GCV delivered by the hemagglutinating virus of Japan (HVJ) liposome, with or without heating. Mice with subcutaneously xenografted tumors and peritoneal carcinomatosis were treated with hyperthermia and gene therapy using the HVJliposome-carrying HSP-tk. Assessment by luciferase assay demonstrated highly inducible and tumor-specific promoter activity in vitro and in vivo. Cytotoxic assays showed that cells transfected with HSP-tk became more sensitive to GCV with heating. A synergistic effect was also observed when treated with a non-heat-inducible cytomegalovirus (CMV) promoter-mediated HSV-tk/GCV and heating, indicating bystander killing. The HVJ-liposome-carrying HSP-tk/GCV combined with hyperthermia significantly inhibited the growth of subcutaneous tumors and prolonged survival of mice with peritoneal carcinomatosis. We conclude that the combination of suicide gene therapy with hyperthermia can provide a promising treatment modality for advanced gastric cancer.

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