微小RNA-34b及靶基因c—Myc在膀胱癌中的作用

The roles of microRNA-34b and its target c-Myc in bladder cancer

目的探讨微小RNA（miR）-34b及c—Mye在膀胱癌中的作用及验证两者相互作用关系。方法分别通过实时定量聚合酶链反应（ReM—timePCR）检测miR一34b与c—Myc基因在36对膀胱癌及瘤旁组织中的表达，分析两基因表达与肿瘤分类（肌层浸润型与非肌层浸润型）及病理分级的关系。然后，采用Transwell法观察miR一34b及c．Myc对膀胱癌细胞T24侵袭能力的影响，采用生物信息学软件及荧光素酶实验验证miR一34b及c．Myc是否存在直接作用。结果与瘤旁组织比较，c—Myc在膀胱癌中表达升高（3．27±0．68）倍，肌层浸润组c—Myc表达为非肌层浸润组的（2．48±0．32）倍，其表达水平随着病理分级升高而升高（P〈0．05）。相反，miR一34b在膀胱癌中表达降低（2．13±0．43）倍，肌层浸润组miR一34b的表达明显低于非肌层浸润组，后者为前者的（3．78±0．25）倍，miR-34b表达水平随着病理分级升高而降低（P〈0．05）。过表达miR一34b或沉默c—Mye后膀胱癌细胞T24的侵袭能力均降低。生物信息学软件及荧光素酶实验证实c—Myc为miR．34b的直接靶基因。结论miR-34b表达下调可能通过上调其靶基因c—Myc而增加膀胱癌的恶性程度。

Objective To investigate the roles of microRNA （miR）-34b and c-Myc in bladder cancer and examine their interactions. Methods Expression levels of miR-34b and c-Mye in 36 eases of bladder cancer tissues and paired paritumor tissues were deteccted by using real-time quantitative polymer- ase chain reaction （PCR） , and their correlation with tumor classification （ tousle invasive versus non-music invasive） and pathological grade was analyzed. Invasive ability of T24 cells was detected by using Tran- swell assays when miR-34b was overexpressed or c-Myc was silenced. Bioinformatics software and lucifer- ase assay were used to test whether c-Myc was one target of miR-34b. Experiments were repeated three times. Results c-Myc was activated in bladder cancer （3.27 ＋ 0. 68 folds of peritumor tissue） and in- creased with the tumor grade, and c-Myc expression of musle invasive group was 2. 48 ± 0. 32 folds of that of non-music invasive group （all P 〈 0. 05）. However, miR-34b was downregulated （2. 13 ±0. 43） folds in bladder cancer and decreased with the tumor grade, and miR-34b expression of non-music invasive group was 3.78 ＋ 0. 25 folds of that of tousle invasive group （ all P 〈 0. 05 ）. Furthermore, overexpression of miR-34b or knockdown of c-Myc suppressed the cell invasion of T24 cells. Bioinformatics software and lu- ciferase assay confirmed that c-Myc was one target of miR-34b. Conclusion miR-34b targeted c-Myc in bladder cancer and may be associated with tumor malignancy.