Backround

CSCs having the common features of high telomerase activity and high migration and invasion capabilities play a vital role as the initiators of metastasis. Small molecule BIBR1532 has been shown to target cancer cells by inhibiting telomerase. Recent studies have suggested that telomerase activity is associated with epithelial mesenchymal transition (EMT). EMT program, which causes epithelial cells to acquire a mesenchymal morphology, is known to play a significant role in cancer metastasis.

Methods

The hypothesis of our study was that suppression of telomerase in breast cancer and cancer stem cells would interrupt EMT mechanism. Cytotoxicity of BIBR1532 was evaluated using WST-1 assay in all cell lines and the effects of BIBR1532 on apoptosis were investigated with Annexin V. Migration rate of the cells was examined by wound healing assay and sphere forming capacities were observed by hanging drop test. Finally, the expression of 84 EMT-related genes was analyzed by real-time qPCR.

Results

The IC₅₀ values for the MDA-MB-231 and breast epithelial stem cells of BIBR1532 were analyzed as 18.04 and 38.71 µl at 72 hours, respectively. Interestingly, apoptosis was only induced in stem cells. In hanging drop test, sphere areas were reduced in stem cells treated with BIBR1532. In wound healing assay, BIBR1532 decreased the migration rate of stem cells. Together with this, expression of EMT-related genes were regulated in stem cells towards a epithelial phenotype.

Conclusion

Our obtained results indicated that telomerase inhibition affects the EMT mechanism. The targeted elimination of breast cancer stem cells by a telomerase inhibitor in cancer treatment may limit the mobility and stemness of cancer cells due to the EMT mechanism, thus may prevent metastasis.

中文翻译：

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端粒酶抑制调节乳腺癌干细胞中的 EMT 机制。

背景

具有高端粒酶活性和高迁移和侵袭能力的CSC作为转移的起始者起着至关重要的作用。小分子 BIBR1532 已被证明通过抑制端粒酶来靶向癌细胞。最近的研究表明，端粒酶活性与上皮间质转化（EMT）有关。EMT程序导致上皮细胞获得间充质形态，已知在癌症转移中起重要作用。

方法

我们研究的假设是抑制乳腺癌和癌症干细胞中的端粒酶会中断 EMT 机制。BIBR1532 的细胞毒性在所有细胞系中使用 WST-1 试验进行评估，并用 Annexin V 研究 BIBR1532 对细胞凋亡的影响。通过伤口愈合试验检查细胞的迁移率，并通过悬滴试验观察球形成能力。最后，通过实时qPCR分析了84个EMT相关基因的表达。

结果

BIBR1532 的 MDA-MB-231 和乳腺上皮干细胞在 72 小时时的 IC _{50值分别为 18.04 和 38.71 µl。}有趣的是，细胞凋亡仅在干细胞中被诱导。在悬滴试验中，用 BIBR1532 处理的干细胞中的球体面积减少。在伤口愈合试验中，BIBR1532 降低了干细胞的迁移率。与此同时，EMT 相关基因的表达在干细胞中被调节为上皮表型。

结论

我们获得的结果表明端粒酶抑制会影响 EMT 机制。在癌症治疗中通过端粒酶抑制剂靶向消除乳腺癌干细胞可能会由于 EMT 机制而限制癌细胞的移动性和干性，从而可能防止转移。