Lu Yi, Chen Qiuyan, Corey Eva, Xie Wen, Fan Jie, Mizokami Atsushi, Zhang Jian
Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15240, USA.
Clin Exp Metastasis. 2009;26(2):161-9. doi: 10.1007/s10585-008-9226-7. Epub 2008 Nov 11.
Prostate cancer (PCa) frequently metastasizes to bone resulting in a mixture of osteolytic and osteoblastic lesions. We have previously reported that monocyte chemotactic protein-1 (MCP-1) is chemotactic for PCa cells, and its receptor, CCR2 expression, correlates with pathological stages. However, the role of MCP-1/CCR2 axis on PCa progression in bone remains unclear. We first evaluated the serum levels of MCP-1 in patients with bone metastases or localized PCa by enzyme-linked immunosorbent assay. We found that MCP-1 levels were elevated in patients with bone metastases compared to localized PCa. We further determined the effects of knockdown CCR2 or MCP-1 on PCa cell invasion and the tumor cell-induced osteoclast activity in vitro, respectively. PCa C4-2B and PC3 cells were transfected stably with either CCR2 short hairpin RNA (shRNA) or a scrambled RNA. CCR2 knockdown significantly diminished the MCP-1-induced PCa cell invasion. In addition, the MCP-1 production was knocked down by MCP-1 shRNA in C4-2B and PC3 cells. Conditioned media (CM) was collected and determined for the CM-induced osteoclast formation in vitro. MCP-1 knockdown significantly decreased the PCa CM-induced osteoclast formation. Finally, MCP-1 knockdown PC3 cells were implanted into the tibia of SCID mice for 4 weeks. Tumor volume was determined by histopathology and bone histomorphometry. MCP-1 knockdown diminished PC3 tumor growth in bone. We concluded that activation of MCP-1/CCR2 axis promotes PCa growth in bone. This study suggests that MCP-1 may be a target for PCa progression.
前列腺癌（PCa）常转移至骨骼，导致溶骨性病变和成骨性病变并存。我们之前报道过单核细胞趋化蛋白-1（MCP-1）对PCa细胞具有趋化作用，其受体CCR2的表达与病理分期相关。然而，MCP-1/CCR2轴在PCa骨转移进展中的作用仍不清楚。我们首先通过酶联免疫吸附测定法评估了骨转移患者或局限性PCa患者血清中MCP-1的水平。我们发现，与局限性PCa患者相比，骨转移患者的MCP-1水平升高。我们进一步分别确定了敲低CCR2或MCP-1对PCa细胞侵袭以及体外肿瘤细胞诱导的破骨细胞活性的影响。PCa C4-2B和PC3细胞分别用CCR2短发夹RNA（shRNA）或乱序RNA进行稳定转染。敲低CCR2可显著减少MCP-1诱导的PCa细胞侵袭。此外，C4-2B和PC3细胞中的MCP-1表达通过MCP-1 shRNA被敲低。收集条件培养基（CM）并测定其在体外诱导破骨细胞形成的能力。敲低MCP-1可显著减少PCa CM诱导的破骨细胞形成。最后，将敲低MCP-1的PC3细胞植入SCID小鼠的胫骨中4周。通过组织病理学和骨组织形态计量学确定肿瘤体积。敲低MCP-1可减少PC3肿瘤在骨中的生长。我们得出结论，MCP-1/CCR2轴的激活促进了PCa在骨中的生长。这项研究表明MCP-1可能是PCa进展的一个靶点。
