基于“肾主骨”理论探讨左归丸对恶性肿瘤破骨性骨转移的治疗作用及其生物学基础

Bone marrow is a heterogeneous organ containing diverse cell types, and it is a preferred metastatic site for several solid tumors such as breast and prostate cancer. These conditions have a profound impact on patients' quality of life and lead to impaired mobility. Therefore, the study of skeletal metastasis has been an important topic in carcinoma treatment. Bone metastasis can be classified into osteolytic, osteoblastic, and mixed, according to the primary mechanism of interference with normal bone remodeling. And more than 70% patients with marked disturbances of bone remodeling are lytic lesions. Nowadays, the “vicious cycle” hypothesis of osteolytic metastases is set up between cancer cells and bone, and the role of RANKL–RANK–OPG system is well character within lytic bone metastasis. In the opinion of Theory of TCM, osteolytic metastasis belongs to osteoma, bone rheumatism etc.. The location of this disease is in kidney, and its cause can come down to deficiency of the kidney. Zuogui Pills, which is a typical prescription of nourishing yin and tonifying the kidney, can be applicable to treatment of osteoporosis. Led by these concepts, we tested whether this Chinese Medicine would cause similar effects on bone metastasis induced by breast cancer cells. It was shown that Zuogui Pills have the potential to prevent bone loss induced by breast cancer cells. The mechanisms of action of this Traditional Chinese medicine may be associated with suppression of RANKL/RANK activation. Based on these findings, we here hypothesize that Zuogui Pills suppress osteolytic metastasis through down-regulating activities of RANKL-RANK system. The specific aim of this program is evaluation of the properties of Zuogui Pills on bone metastasis and clarification of its mechanisms by targeting interaction between cancer cells and bone in breast cancer and lung cancer. To convince our hypothesis, we will (1) evaluate anti-metastatic properties of Zuogui Pills in vivo and in vitro; (2) analyze the mechanisms of Zuogui Pills on RANKL-RANK axis. These investigations will provide a foundation for elucidation of effects and mechanisms of Zuogui Pills to prevent osteolytic metastasis.

骨转移是恶性肿瘤的常见并发症，其中70%为破骨性骨转移，溶骨性骨吸收异常是其主要病理表现，肿瘤细胞、成骨细胞和破骨细胞之间相互作用的“恶性循环”是其发病的主要机制。中医理论认为，骨转移属“骨瘤”、“骨痹”、“骨蚀”等的范畴，其病位在肾，肾虚是其重要病因，治法则以补肾为主。左归丸是滋阴补肾法的代表方剂，可用于骨质疏松等多种骨吸收异常疾病。据此，我们推测左归丸对同属骨吸收异常性疾病的破骨性骨转移可能具有治疗作用。前期研究初步证实了左归丸的这一作用，其机制涉及破骨细胞活化抑制。为进一步确证其疗效、探索其生物学基础，本课题将采用多种动物模型验证左归丸的治疗作用，并围绕肿瘤细胞-成骨细胞-破骨细胞的相互作用，从细胞水平和分子水平阐明其机制。本研究在“肾主骨”理论的指导下，从传统方剂中发掘治疗破骨性骨转移的新手段，不仅对于该疾病的治疗有着重要的临床意义，也可进一步丰富人们对中医理论的认识。

骨转移是恶性肿瘤的常见并发症，其中70%为破骨性骨转移，溶骨性骨吸收异常是其主要病理表现，肿瘤细胞、成骨细胞和破骨细胞之间相互作用的“恶性循环”是其发病的主要机制。中医理论认为，骨转移属“骨瘤”、“骨痹”、“骨蚀”等的范畴，其病位在肾，肾虚是其重要病因，治法则以补肾为主。左归丸是滋阴补肾法的代表方剂，可用于骨质疏松等多种骨吸收异常疾病。据此，我们推测左归丸对同属骨吸收异常性疾病的破骨性骨转移可能具有治疗作用。前期研究初步证实了左归丸的这一作用，且其机制涉及破骨细胞活化抑制。为进一步确证其疗效，本项目在此基础上采用多种体内骨转移动物模型验证左归丸对破骨性骨转移的治疗作用，并围绕肿瘤细胞-成骨细胞-破骨细胞的相互作用，从细胞水平和分子水平阐明其作用机制。.体内药效方面，分别采用左心室及股骨内注射肿瘤细胞的方法建立裸鼠乳腺癌实验性骨转移模型，并采用巢式PCR特异性扩增裸鼠骨髓中人ck19细胞，确定肿瘤细胞在骨髓组织中的转移情况。结果表明，与空白对照组相比，左归丸可显著抑制乳腺癌以及肺癌骨转移动物骨髓组织中人ck19表达的影响。.体外药效方面，左归丸含药血清可显著抑制BMMs分化为具有多细胞核的破骨细胞，同时可显著抑制破骨细胞分泌Cathepsin K。骨片吸收实验表明，10%左归丸含药血清组的骨片吸收窝的数量和面积显著低于正常大鼠血清组。体外迁移实验表明，左归丸含药血清可显著TGF-β诱导的肿瘤细胞迁移；左归丸也可显著抑制乳腺癌细胞对重组基底膜的侵袭能力。.机制研究方面，左归丸含药血清可显著抑制F-actin聚合，抑制F-actin聚合体的形成，进而影响肿瘤细胞的迁移和侵袭。另外，左归丸还可显著抑制BMMs 小鼠骨髓巨噬细胞RANK表达和肿瘤细胞PTHrP和CXCR4的表达。.本项目在“肾主骨”理论的指导下，研究了左归丸对破骨性骨转移的治疗作用及其可能作用机制。从传统方剂中发掘治疗破骨性骨转移的新手段，不仅对于该疾病的治疗有着重要的临床意义，也可进一步丰富人们对中医理论的认识。