一种新的长链非编码RNA-Linc00324在乳腺癌侵袭和转移中的作用和分子机制研究

Breast cancer is one of the leading causes of cancer-related mortality amongst female worldwide, and metastasis is the major cause of death associate with breast cancer. Linc00324 is a new found long intergenic noncoding RNA. Our previous studies revealed that Linc00324 is a cytoplasmic RNA, which was down-regulated significantly in metastatic breast cancer and breast cancer cell line BT549, and could inhibit the proliferation and colony formation of BT549 cell line. By gene sequence analysis, we found Linc00324 is located in 774 bp downstream of the 3’UTR of CTC1 gene. Our previous studies also showed that the expression of CTC1 decreased significantly in non-metastatic breast cancer. These results remind us that Linc00324 may prevent the metastasis in breast cancer, and CTC1 may be one of its target genes. So we will use molecular biology and other techniques to perform the following work: (1) to investigate the relationship between the expression of Linc00324 and CTC1 and the clinical significance in breast cancer; (2) to explore the role and molecular mechanism of Linc00324 in the metastasis and invasion of breast cancer; (3) role of Linc00324 in the regulation of CTC1 expression and telomerase activity; (4) to identify Linc00324 interacted protein and study its function. This project will elucidate the regulating mechanism of Linc00324 in metastasis and invasion of breast cancer and provide the experimental data for gene diagnosis and targeted therapy of breast cancer.

侵袭转移是导致乳腺癌患者死亡的主要原因，故寻找有效分子治疗靶点预防乳腺癌复发转移有重要意义。Linc00324是新近发现的一种LncRNA，其基因位于CTC1基因的下游。我们前期研究表明Linc00324定位于细胞浆；在转移性乳腺癌组织表达明显降低；可抑制乳腺癌细胞增殖和克隆形成；而CTC1在非转移乳腺癌组织表达明显减少。据此我们推测Linc00324可能有抑制乳腺癌侵袭转移的作用，CTC1可能是其靶基因之一。故本课题拟研究：Linc00324与CTC1表达和临床指标的相关性；体内、外观察Linc00324对乳腺癌细胞侵袭转移能力的影响；Linc00324对CTC1表达、EMT相关分子及信号通路的影响；鉴定Linc00324的互作蛋白并研究其作用。本项目有助于揭示Linc00324调控乳腺癌侵袭转移的分子机制，为逆转乳腺癌侵袭转移提供新的理论依据，为乳腺癌基因诊断和靶向治疗提供实验依据。

越来越多的研究表明长链非编码RNA可作为肿瘤的特异标志物。LINC00324广泛表达于包括乳腺在内的多种组织，然而其在乳腺癌的发生发展中的作用尚未清楚。通过本课题研究，我们发现LINC00324乳腺癌组织和乳腺癌细胞株中的表达量明显下调，并与组织和细胞的恶性程度相关。LINC00324过表达于MDA-MB-231细胞株可抑制增殖、侵袭和迁移，并诱导凋亡，相反，干扰LINC00324则增强细胞的恶性表型。进一步研究发现LINC00324主要存在于细胞浆，并通过对miR-10b-5p 的“海绵吸附作用”促进E-cadherin的表达。总之研究结果表明LINC00324通过与miR-10b-5p的相互作用在乳腺癌的发生发展中起到非常关键的作用，可作为乳腺癌早期诊断的标志物和新的治疗靶标。