Gan R, Yang Y, Yang X, Zhao L, Lu J, Meng Q H
Wenzhou Medical University School of Laboratory Medicine and Life Sciences, Wenzhou, China.
1] Wenzhou Medical University School of Laboratory Medicine and Life Sciences, Wenzhou, China [2] Key Laboratory of Laboratory Medicine, Ministry of Education, Wenzhou, China [3] Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou, China.
Cancer Gene Ther. 2014 Jul;21(7):290-6. doi: 10.1038/cgt.2014.29. Epub 2014 Jun 13.
Aberrantly expressed microRNAs (miRNAs) are involved in breast tumorigenesis. It is still unclear if and how miRNAs-221/222 are implicated in breast cancer and the resistance to estrogen receptor modulator tamoxifen. We investigated the roles and mechanisms of miR-221/222 in breast cancer cells, particularly in modulating response to tamoxifen therapy. MCF-7 and MDA-MB-231 breast cancer cells were transfected with antisense oligonucleotides AS-miR-221 and AS-miR-222 and their expression of miR-221 and miR-222 was assessed. The correlation of miR-221/222 with tissue inhibitor of metalloproteinase-3 (TIMP3) expression was investigated by fluorescence quantitative PCR and western blotting analysis. The therapeutic sensitivity of these cells, transfected and untransfected, to tamoxifen was determined. Transfection of AS-miR-221 and AS-miR-222 dramatically inhibited expression of miR-221 and miR-222, respectively, in both MCF-7 and MDA-MB-231 cells (P<0.05-0.01). Downregulation of miR-221/222 significantly increased the expression of TIMP3 compared with controls (P<0.05-0.01). The viability of estrogen receptor (ER)-positive MCF-7 cells transfected with AS-miR-221 or/and AS-miR-222 was significantly reduced by tamoxifen (P<0.05-0.01). We have demonstrated for the first time that suppression of miRNA-221/222 increases the sensitivity of ER-positive MCF-7 breast cancer cells to tamoxifen. This effect is mediated through upregulation of TIMP3. These findings suggest that upregulation of TIMP3 via inhibition of miRNA-221/222 could be a promising therapeutic approach for breast cancer.
异常表达的微小RNA（miRNA）参与乳腺癌的发生。miRNA-221/222是否以及如何与乳腺癌及对雌激素受体调节剂他莫昔芬的耐药性相关仍不清楚。我们研究了miR-221/222在乳腺癌细胞中的作用和机制，特别是在调节对他莫昔芬治疗反应方面的作用和机制。用反义寡核苷酸AS-miR-221和AS-miR-222转染MCF-7和MDA-MB-231乳腺癌细胞，并评估它们的miR-221和miR-222表达。通过荧光定量PCR和蛋白质印迹分析研究miR-221/222与金属蛋白酶组织抑制剂-3（TIMP3）表达的相关性。测定这些转染和未转染细胞对他莫昔芬的治疗敏感性。转染AS-miR-221和AS-miR-222分别显著抑制MCF-7和MDA-MB-231细胞中miR-221和miR-222的表达（P<0.05 - 0.01）。与对照组相比，miR-221/222的下调显著增加了TIMP3的表达（P<0.05 - 0.01）。用AS-miR-221或/和AS-miR-222转染的雌激素受体（ER）阳性MCF-7细胞的活力被他莫昔芬显著降低（P<0.05 - 0.01）。我们首次证明抑制miRNA-221/222可增加ER阳性MCF-7乳腺癌细胞对他莫昔芬的敏感性。这种作用是通过上调TIMP3介导的。这些发现表明，通过抑制miRNA-221/222上调TIMP3可能是一种有前景的乳腺癌治疗方法。
