去势抵抗和转移是晚期前列腺癌患者死亡的主要原因，长链非编码RNA(lncRNAs)表达失调是去势抵抗前列腺癌(CRPC)发生和转移的关键，但机制未明。外泌体在肿瘤发生进展中发挥重要作用，但其在前列腺癌中的机制尚不明确。我们的前期研究发现lncRNA-HOXD-AS1在CRPC细胞中高表达，通过外泌体在前列腺癌细胞间传递，并初步证实HOXD-AS1能够特异性结合miR-205。由此我们提出关于前列腺癌进展的机制的猜想：外泌体HOXD-AS1由CRPC细胞传递至其他前列腺癌细胞，通过竞争性结合miR-205促进下游去势抵抗及转移相关基因表达，从而促进前列腺癌进展及转移。本研究拟进一步通过体内外实验，MS2-TRAP等技术获得外泌体HOXD-AS1通过结合mir-205调控前列腺癌进展的可靠证据，确定其在前列腺癌中的临床意义，为发现新的体液活检标记物和治疗靶点提供理论依据

Castration resistance and metastasis are the leading causes of death in patients with advanced prostate cancer. Deregulation of long non-coding RNAs is the key factor in the castration resistance and metastasis of prostate cancer, however, the underlying mechanism remains to be elucidated. Exosomes are important regulators in cancer progression, yet their potential roles and molecular mechanisms in prostate cancer are poorly understood. Our study found that the lncRNA HOXD-AS1 was overexpressed in castration resistant prostate cancer cell lines, and transmitted among prostate cancer cells through exosomes. Furthermore, we identified that HOXD-AS1 competitively bound to miR-205. Therefore, we propose the new mechanism that exosomal transmitted lncRNA HOXD-AS1 promotes castration resistance and metastasis of prostate cancer by sponging miR-205，and then facilitates miR-205 downstream gene expression. To gain the proof of exosomal lncRNA HOXD-AS1 promotes castration resistance and metastasis by sequestering miR-205, we will perform in vitro and vivo experiments, crosslink RNA Immunoprecipitation and dual luciferase experiment. This study aims to elucidate the function and mechanism of exosomal lncRNA HOXD-AS1 in prostate cancer and how they modulate castration resistance and metastasis by binding miR-205. To identify the clinical significance of exosomal HOXD-AS1, the new therapeutical targets and bio-marker of liquid biopsy for castration resistant prostate cancer.