抗藥性大腸癌細胞株及其小鼠腫瘤動物模式之建立

腫瘤細胞過度表現多重藥物抗藥性(multidrug resistance; mdr)基因為癌症化學治療失敗的主要原因之一，mdr1基因產物為細胞膜上之轉運蛋白P-glycoprotein (P-gp)，此蛋白將藥物從細胞中排出而呈現抗藥性。本論文的研究目的篇建立具有多重藥物抗藥性的腫瘤細胞株及其小鼠腫瘤動物模式，以應用於腫瘤抗藥性之研究。小鼠大腸癌CT-26細胞(CT-26/WT)培養於加入doxorubicin (DOX)的培養基中，DOX濃度以漸進式由低至高濃度(1nM-1μM)，所得的抗藥性細胞稱為CT-26/DOX1。結果顯示CT-26/DOX1細胞對於DOX的抵抗倍率(resistant Index; RI)相較於CT-26/DOX1。結果顯示CT-26/DOX1細胞對於DOX的抵抗倍率(resistant index; RI)相較於CT-26/WT爲90倍，P-gp基質化療藥物vincristine和etoposide的RI也高於CT-26/WT，而非P-gp基質之化療藥物5-FU和methotrexate，其RI則與CT-26/WT相似。在P-gp蛋白表現和功能方面，CT-26/DOX1細胞顯著高於CT-26/WT。將細胞皮下接種於小鼠，於CT-26/WT和CT-26/DOX1活體腫瘤大小約75-250 mm^3時，每週靜脈注射DO×1劑，劑量為10 mg/kg，共投與三劑，發現CT-26/DO×1腫瘤大小極顯著高於CT-26/WT。綜合上述結果顯示本研究已建立抗藥性CT-26/DO×1細胞模式以及CT-26/DOX1的實驗動物模式。

關鍵字

CT-26大腸癌；多重藥物抗藥性；動物模式；小鼠

並列摘要

Overexpression of the mdr1 gene in cancer cells is one of the major underlying mechanisms responsible for failure of cancer chemotherapy. P-glycoprotein (P-gp), the plasma membrane protein encoded by mdr1 gene, acts as an energy-dependent efflux transporter that reduces intracellular concentrations of various cytotoxic drugs to sublethal concentrations. The objective of the present study is to establish a MDR colon carcinoma cell line and a murine tumor model for study of tumor MDR in vitro and in vivo. The parental CT-26 cells (CT-26ANT) were cultured in RPMI medium with gradually increased concentrations of doxorubicin (DOX; from 1 nM to 1 μM) to establish a MDR sub-line (CT-26/DOX1). Cytotoxicity measured by the MU assay demonstrated that the 50% inhibition concentration (IC50) of DCX in CT-26/DOX1 was significantly higher than that in CT-26/WT. The resistant index (RI) of CT-26/DOX1 cells to DOX was 90 folds as compared to the CT-26/WT cells. In addition to DCX, CT-26/DOX1 exhibited resistance to vincristine and etoposide that are also P-gp substrates, but not to 5-fluoruracil and methotrexate that are not P-gp substrates. These data suggest a phenotype of MDR in the CT-26/DOX1 sub-line. The phenotype of MDR was further confirmed by the increased levels of P-gp protein expression, and P-gp function in CT26/DOX1. Finally, the effect of DOX on the growth rate of CT-26/WT and CT-26/DOX1 tumor implants in BALB/c mice was measured. DOX was intravenously administered (10 mg/kg; once per week for 3 doses) into tumor-bearing mice when the size of tumor implants reached 75-250 mm^3. The results showed that the tumor growth rate in CT-26/DOX1 was significantly greater than that in CT-26M/T after the 2 dose of DCX. In conclusion, the present studies have established a MDR CT-26/DOX cell sub-line, and a CT-26/DOX1 syngeneic murine model with MDR phenotype.

並列關鍵字

CT-26 ； multidrug resistance ； animal model ； mouse

國際替代計量

抗藥性大腸癌細胞株及其小鼠腫瘤動物模式之建立

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