A Research Investigating The Tumor Inhibition Rate, Expression Of Cyclin D1 And B1 On The CNE-1 Xenografted Nude Mice In Intensity-modulated Radiationtherapy Mode

Objective: To investigate the differences of tumor inhibittion and expression of Cyclin D1/B1 in simulated IMRT and which combined with cisplatin in well differential xenografted NPC in Nude Mouse. Method: Nude mice got CNE-1 cell line on their right legs, and then devided into control arm, cisplatin arm, regular radiotherapy arm, simulated IMRT arm and IMRT+cisplatin arm. 12 mice are included in each arm. Regular RT arm receives 20Gy 6-MV X-ray with dose ratio 300cGy per min, while the IMRT arm and IMRT+cisplatin arm receive 20Gy 6-MV X-ray in 30 minutes with 15 fractions. The cisplatin arm and IMRT+cisplatin arm receive cisplatin injection at the dose of 15 microgram per gram weight in their abdominal cavities. Then measure the maximum diameter of tumor base every other day and draw the growth curve after 40 days, and test the expression of Cyclin D1 and B1 with RT-PCR. Result: (1) Tumor inhibition rate: the control arm, cisplatin arm, regular RT arm, IMRT arm and IMRT+cisplatin arm are -129.09%, -71.23%, 42.49%, 35.26% and 47.09%, respectively. There is significant difference between the regular RT arm and the IMRT arm (P=0.034), but there is no such difference between the regular RT arm and the IMRT+cisplatin arm (P=0.222). (2) Expresssion of Cyclin B1: The expression of those arm are 0.4293, 0.3863, 0.3222, 0.3540 and 0.2681. There is significant differences between the regular RT arm and the IMRT arm or the IMRT+cisplatin arm (P=0.007,P=0.000). (3) Expresssion of Cyclin D1: The expression of those arm are 0.7158, 0.5832, 0.3479, 0.4954 and 0.2962. There is significant difference between the regular RT arm and the simulated IMRT arm (P=0.000), but there is no such difference between the regular RT arm and the IMRT+cisplatin arm (P=0.072). Conclusion: (1) Radio therapy (including regular RT and IMRT), cisplatin based chemotherapy and cisplatin based concurrent radio-chemotherapy are all effective to the CNE-1 xenografted nude mice. Using cisplatin along can't decrease the diameter, but it can delay the growth speed; (2) As prolonging the single theraputic time in IMRT mode, the tumor inhibition rate declines, while cisplatin can end such tendency and promote it to the regular RT level. (3) Radio therapy, cisplatin based chemotherapy and concurrent radio-chemotherapy can down regulate the Cyclin B1/D1 expression, but IMRT's effectiveness is not as strong as regular RT. IMRT+cisplatin can down regulate their value continuous to the regular RT level. (4) Cisplatin can develop radiosensitization. That means it can compensate the decline of biological effect in IMRT mode.