| Budget Amount *help |
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2011: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2010: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
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| Research Abstract |
Radiotherapy is an important noninvasive treatment for many types of cancer.
Recently, remarkable progress of technology of radiotherapy leads to an improvement of local control rate. However, the emergence of tolerant cells during or after radiotherapy remains problematic. The patients who relapsed by repopulated tumor have worse prognoses because of more malignant character of repopulated tumor compared with that of before irradiation. Unfortunately, the molecular mechanisms of cause for tumor repopulation remain unknown. To elucidate the molecular profile of repopulated tumor, present study analyzed the cellular properties of surviving tumor after X-ray irradiation by using IR cells which is the model cell line of repopulated tumor. In the present study, we analyzed the role of Neuropilin 1(NRP1) in radiation surviving cells(IR cells). NRP1 is a well known as an angiogenesis and cell motility related molecule. Although the mRNA expression levels of NRP1 were up-regulated in IR cells
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compared with parental cells, the protein expression of NRP1 was the same level between parental cells and IR cells. To analyze the activity of angiogenesis in IR cells, we performed tube formation assay and Plasma Clot assay by using human umbilical vein endothelial cells(HUVEC). However, IR cells indicated the same levels of anginogenic activity compared to that of parental cells. The secretion level of vascular endothelial growth factor(VEGF) was also the same level between parental cells and IR cells using ELISA. On the other hand, the NRP1 localization in the cells was different between those two cell lines. Though NRP1 was observed as a vesicle-like constructs in both cell lines, the amount of vesicles was 1. 5-fold decreased in IR cells. These vesicles were not co-localized with EEA1, an early endosome-associated protein. The association of NRP1 with integrin 5 1 was not observed in both cells, whereas the interaction of integrin V 3 and NRP1 was detected by immunoprecipitation assay. Though these interactions were the same levels between two cells, integrin may associates with the control of NRP1 localization. Further studies will be necessary to clarify the function of up-regulated-NRP1 in IR cells, interaction between integrin and NRP1 may lead to control behavior of up-regulation of cell motility in IR cells. Less
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