Folding of single-stranded circular DNA into rigid rectangular DNA accelerates its cellular uptake.

Despite the importance of the interaction between DNA and cells for its biological activity, little is known about exactly how DNA interacts with cells. To elucidate the relationship between the structural properties of DNA and its cellular uptake, a single-stranded circular DNA of 1801 bases was designed and folded into a series of rectangular DNA (RecDNA) nanostructures with different rigidities using DNA origami technology. Interactions between these structures and cells were evaluated using mouse macrophage-like RAW264.7 cells. RecDNA with 50 staple DNAs, including four that were Alexa Fluor 488-labeled, was designed. RecDNA with fewer staples, down to four staples (all Alexa Fluor 488-labeled), was also prepared. Electrophoresis and atomic force microscopy showed that all DNA nanostructures were successfully obtained with a sufficiently high yield. Flow cytometry analysis showed that folding of the single-stranded circular DNA into RecDNA significantly increased its cellular uptake. In addition, there was a positive correlation between uptake and the number of staples. These results indicate that highly folded DNA nanostructures interact more efficiently with RAW264.7 cells than loosely folded structures do. Based on these results, it was concluded that the interaction of DNA with cells can be controlled by folding using DNA origami technology.

[Indication and meaning of hepatic resection for metastatic liver tumors from gastric cancer].

To clarify the efficacy and indication of hepatectomy in gastric cancer metastasis to the liver, we studied 26 liver metastases patients undergoing hepatectomy. The cumulative 5-year survival rations were 25.3%. A survival analysis showed that prognoses of patients n(-) or T2 group were statistically better than other group. Three patients underwent a repeat liver resection from gastric metastasis and survived for about thirty months. There was an example using chemotherapy which made a liver tumor removal operation possible to the patient who had multiple liver metastases. In conclusion, liver resection is a beneficial option and multimodal therapy including a repeat liver resection and systemic chemotherapy, may be important for improving the prognosis of patients with liver metastases from gastric cancer.

[A case report of recurrence of liver metastases from colorectal cancer, which seemed to have vanished for a time by intra-aortic chemotherapy].

A 66-year-old man underwent lower anterior resection for rectum cancer with multiple liver metastases. The diagnosis was Stage IV well-differentiated tubular adeno carcinoma. n1H3M(-). As adjuvant chemotherapy, we chose intra-arterial infusion of 5-FU 1,500 mg/body/week from July 2002 to February 2003. The metastatic focuses have become smaller and smaller until they seemed to be scars. In July 2003, there appeared to be a liver metastasis again, which emerged at the same place of the first metastatic focus. We tried intra arterial infusion of DXR in addition to intra-venous infusion of CPT-11, but it seemed to have no effect. Finally, we performed a partial resection of the liver in March 2005. There were many metastatic legions that emerged, but we successfully carried through partial resections for all legions. The uniqueness of this case was the liver metastasis that had appeared at the same place of the first metastatic focus. As the strategy for liver metastasis of colon cancer, it is better to perform a surgical resection as soon as the focus becomes resectable.