lncRNA MALAT1 作为竞争性内源RNA调控骨髓瘤肿瘤生长及血管新生的机制研究

Aberrant expression of long non-coding RNAs (lncRNAs) is associated with various human cancers. Recently, reports have demonstrated that lncRNAs may function as a competing endogenous RNAs (ceRNAs) to miRNAs. So far, the functional role and mechanism of lncRNA in multiple myeloma (MM) are unknown. Our preliminary data showed that the levels of lncRNA MALAT1 were up-regulated in various MM cell lines. Moreover, the proliferation ability of MM cells was inhibited after treated with MALAT1 siRNA. Bioinformatics prediction for miRNA recognition sequences in MALAT1 indicating the presence of a putative binding site for miRNA-15a/16, which has been proved to regulate proliferation and angiogenesis in MM by targeting VEGF/cyclinD1.Therefore, we speculate that MALAT1 may function as a ceRNA to regulate VEGF/cyclinD1 levels by sponging miRNA-15a/16 and consequently promote angiogenesis and tumor growth in MM. Detection and comparison of MALAT1 expression levels in CD138+ cells from healthy donors and MM patients will be carried out by qRT-PCR analysis and then its relationship with clinical significance of MM will be evaluated. Furthermore, luciferase reporter assay and RIP assay will be used to verify that MALAT1 competes for binding to miRNA-15a/16 in an Argonaute-dependent manner, thereby affecting the derepression of VEGF/cyclinD1. Finally, the role of the ceRNA regulatory network, MALAT1-miRNA-15a/16-VEGF/cyclinD1, in regulating tumor growth and angiogenesis will be tested in vitro and in vivo. This study will provide a novel insight into the role of ceRNA regulatory network in cancer, and a novel molecular target for MM.

长链非编码RNA（lncRNA）可作为竞争性内源RNA，通过与miRNA结合促进肿瘤的发生发展，追踪文献表明lncRNA在多发性骨髓瘤（MM）中的功能和调控机制研究迄今未见报道。前期我们发现lncRNA MALAT1在多种MM细胞系上表达上调，下调其表达可显著抑制MM细胞增殖。生物信息学预测MALAT1可能与miRNA-15a/16结合，而后者已被课题组证实通过靶向VEGF/cyclinD1等调控MM血管新生和肿瘤生长，据此我们推测MALAT1通过竞争性结合miRNA-15a/16，解除其对靶基因的抑制，促进MM发生发展。本课题将比较正常人和MM患者上MALAT1的表达水平，初步揭示其临床意义，然后在细胞和活体动物水平验证这一机制是否参与调控MM肿瘤生长和血管新生。本研究将两种非编码RNA功能结合，首次探讨了MALAT1通过竞争性内源RNA活性在MM发病机制中的作用，为MM诊治提供新思路。

多发性骨髓瘤是浆细胞恶性增殖性疾病，是血液系统的第二大恶性肿瘤，约占整个血液肿瘤10%左右。目前MM尚无根治办法，且复发和耐药仍然是当前临床医师无法克服的问题。非编码RNA是基因表达的重要调控者，越来越多的研究证据表明非编码RNA与MM的发生、发展和预后密切相关，大部分非编码序列均转录成长链非编码RNA（lncRNA）。长链非编码RNA可作为竞争性内源RNA，通过与miRNA结合促进肿瘤的发生发展。.本研究发现lncRNA MALAT1在多种MM细胞系上表达上调，且MM患者骨髓CD138+细胞中MALAT1表达量明显高于正常对照组患者标本。下调其表达可显著抑制MM细胞增殖、促进其凋亡并将其细胞周期阻滞在 G0/G1 期。且通过双荧光素酶报告基因检测和RIP实验验证MALAT1与miRNA-15a/16靶向结合，且作为ceRNA 调控 miRNA-15a/16 靶基因 VEGF 的表达水平。后续我们实验组通过体内外功能实验进一步验证了 MALAT1-miRNA-15a/16-VEGF 通路在MM发病机制中的作用。最终得出结论，MALAT1通过竞争性结合miRNA-15a/16，解除其对靶基因VEGF的抑制，促进MM发生发展。.本课题比较了正常人和MM患者上MALAT1的表达水平，初步揭示其临床意义。同时将两种非编码RNA功能结合，探讨了MALAT1通过竞争性内源RNA活性在MM发病机制中的作用，为MM诊治提供新思路。