Kevans David, Gorman Sheeona, Tosetto Miriam, Sheahan Kieran, O'Donoghue Diarmuid, Mulcahy Hugh, O'Sullivan Jacintha
Centre for Colorectal Disease, St. Vincent's University Hospital, Elm Park, Dublin 4, Ireland.
J Gastrointest Cancer. 2012 Jun;43(2):305-13. doi: 10.1007/s12029-011-9277-x.
In vitro studies have shown that clusterin modulates treatment sensitivity in a number of human cancers; however, the interaction between clusterin expression and hypoxia in controlling treatment response in CRC has not previously been examined. The aim of this study was to assess the effect of clusterin overexpression in CRC cells on sensitivity to 5-fluorouracil (5-FU), oxaliplatin and FOLFOX treatment under normoxic and graded hypoxic conditions.
SW480 colon cancer cells were transfected with full length Clusterin cDNA to generate a clusterin overexpressing cell line. Overexpression was confirmed by western blot analysis. The response of parental and clusterin overexpressing cells to 5-FU, oxaliplatin and FOLFOX was examined using a crystal violet-based proliferation assay under normoxic conditions, 3% and 1% hypoxic conditions. The levels of apoptosis and G2/M arrest in FOLFOX-treated cells were assessed by flow cytometry.
Under normoxic conditions, clusterin overexpressing cells were more sensitive to FOLFOX treatment (p = 0.01); under 3% and 1% hypoxic conditions, overexpressing clusterin cells were more sensitive to 5-FU, oxaliplatin and FOLFOX, p values <0.05 for all conditions. Under normoxic conditions, overexpressing clusterin cells showed significantly higher levels of apoptosis when treated with FOLFOX compared to untransfected cells; levels of G2M cells were not significantly different. Under both 3% and 1% hypoxia, the percentage of cells undergoing apoptosis following FOLFOX treatment was significantly higher in overexpressing clusterin cells.
These in vitro findings suggest that tumours expressing high levels of clusterin, particularly if hypoxic in nature, may benefit from treatments such as FOLFOX.
体外研究表明，簇集素可调节多种人类癌症的治疗敏感性；然而，此前尚未研究过簇集素表达与缺氧在控制结直肠癌治疗反应中的相互作用。本研究的目的是评估在常氧和分级缺氧条件下，结直肠癌细胞中簇集素过表达对5-氟尿嘧啶（5-FU）、奥沙利铂和FOLFOX治疗敏感性的影响。
用全长簇集素cDNA转染SW480结肠癌细胞，以生成簇集素过表达细胞系。通过蛋白质印迹分析确认过表达。在常氧条件、3%和1%缺氧条件下，使用基于结晶紫的增殖试验检测亲本细胞和簇集素过表达细胞对5-FU、奥沙利铂和FOLFOX的反应。通过流式细胞术评估FOLFOX处理细胞中的凋亡水平和G2/M期阻滞情况。
在常氧条件下，簇集素过表达细胞对FOLFOX治疗更敏感（p = 0.01）；在3%和1%缺氧条件下，过表达簇集素的细胞对5-FU、奥沙利铂和FOLFOX更敏感，所有条件下p值均<0.05。在常氧条件下，与未转染细胞相比，用FOLFOX处理时，过表达簇集素的细胞显示出明显更高的凋亡水平；G2M期细胞水平无显著差异。在3%和1%缺氧条件下，FOLFOX处理后过表达簇集素的细胞中发生凋亡的细胞百分比均显著更高。
这些体外研究结果表明，表达高水平簇集素的肿瘤，尤其是本质上缺氧的肿瘤，可能从FOLFOX等治疗中获益。
