Therapeutic effect of TNP-470 on spontaneous liver metastasis of colon tumors in the rabbit.

Even though angiogenesis inhibitor is thought to be one of the promising agents in tumor dormancy therapy, its optimal administration is still unknown. Therefore, the efficient protocol using TNP-470 was examined regarding its treatment affect against spontaneous liver metastases of colon tumors in the rabbit. A spontaneous liver metastases model was established in the rabbit by the inoculation of VX-2 tumors into the subserosal space of the colon. The therapeutic effect of TNP-470 was then investigated by monitoring both the number of metastatic nodules in the liver and the microvessel density (MVD) in the tumor by immunohistochemical staining using anti-CD31 monoclonal antibody. TNP-470 did not show any effect on the primary tumor. It was able to reduce the metastatic spread to liver when it was administered at the microscopic metastatic stage. Treatment at this stage, however, was not able to sufficiently control the disease. These results indicated that TNP-470 could efficiently cause the tumor to enter into a dormant state by inhibiting angiogenesis when it was used at the initial stage of the metastatic process in the liver. Regarding its clinical application, TNP-470 might be useful for preventing the metachronous liver metastases of colorectal cancer when it is administered as adjuvant therapy after curative surgery.

Change of temperature in mouse tumour tissue immersed in a water bath at 44 degrees C.

We investigated the change in temperature in tumour and normal tissues of mice when immersed in a water bath at 44.0 degrees C as part of a series of studies of hyperthermia. The right hind legs of the mice bearing the experimental tumour sarcoma 180 were immersed in the water bath, and measurements were performed using the multi-thermocouple thermosensor from a radiofrequency (RF) generator every 24 sec with a precision of 0.1 degrees C. The temperature in all tumour tissues exceeded 43.0 degrees C only at 1 min 24 sec after immersion of the limbs. The rise in temperature then reached a plateau phase, and was maintained around 44.0 degrees C. However, we found that the temperature of the normal tissue was about 0.6 degrees C lower than that of the tumour tissue or the tissue around the tumour at the plateau phase.

[Fundamental study on hyperthermic chemotherapy using adriamycin-loaded hydroxyapatite].

We developed a porous hydroxyapatite ceramic (HAP) incorporating adriamycin (ADM), that is, ADM-HAP as a new delivery system (DDS) to release ADM gradually. We also researched the possibility of hyperthermic chemotherapy using ADM-HAP by in vitro and in vivo experiments. As for in vitro experiments, we implanted HAPs into uniform Agar-Phantom, and observed thermal distribution generated by Thermotron-RF 8 using thermography. Then we found the hot spot that the edge temperature of HAPs always at the range of 0.5-0.7 degrees C than in the other regions. On the other hand, slow constant release (1%) of ADM from ADM-HAP in PBS was recognized for 24 hrs up to 30 days. When the incubating temperature was shifted up to 42.5 degrees C or 44 degrees C from 37 degrees C, the quantity released over 24 hrs increased about 1.1-fold or 1.3-1.4-fold of the cases at 37 degrees C, respectively. In the in vivo experiment, we inoculated Sarcoma 180 cells in the leg of ddY-mice, and measured the tumor growing times by the treatment of hyperthermia+ADM (whole body), hyperthermia+ADM (tumor region) or hyperthermia+ADM-HAP (tumor region). Then we found that the effect of hyperthermia with ADM-HAP inhibited synergistically the tumor growth as compared with hyperthermia with ADM. Consequently, we succeeded in tumor growth inhibition by increasing the temperature and by limiting ADM release to only a target region using hyperthermia with ADM-HAP.