AMD-3465

Diabetic osteoporosis (DOP) is a serious complication of diabetes, which brings a heavy burden to patients' families and society. The SDF-1/CXCR4 signal pathway may be a target to prevent articular cartilage degeneration. In this study, we studied the effects of high glucose (20 mmol/L) and CXCR4 antagonist AMD3465 (10 μmol/L) on the apoptosis and gene expression of osteoblast-like cells MG63 to determine a new treatment for DOP. CCK8 and clone formation assays confirmed that AMD3465 resisted the decrease of proliferation caused by high glucose. According to the results of scratch and transwell analysis, AMD3465 could remedy the decrease of cell migration and invasion induced by high glucose. The results of flow cytometry analysis and double staining with Hoechst and PI showed AMD3465 corrected the apoptosis induced by high glucose. In addition, high glucose regulated the expression of cell cycle- and apoptosis-related proteins, while AMD3465 blocked the regulation of high glucose. Furthermore, high glucose enhanced the expression levels of SDF-1 and CXCR4 in MG63 cells, as well as the release of MMP1, 3, 9 and 13. AMD3465 inhibited the release of MMPs. The results showed that AMD3465 resisted the apoptosis of MG63 cells induced by high glucose, provided a new strategy for the therapy of DOP.

Chemokine CXCL12 and its receptor CXCR4 are constitutively overexpressed in human cancers. The CXCL12-CXCR4 signaling axis plays an important role in tumor progression and metastasis, but also in treatment-induced recruitment of CXCR4-expressing cytotoxic immune cells. Here, we aimed to demonstrate the feasibility of N-[11C]methyl-AMD3465 positron emission tomography (PET) to monitor changes in CXCR4 density in tumors after single-fraction local radiotherapy or in combination with immunization.

TC-1 cells expressing human papillomavirus antigens E6 and E7 were inoculated into the C57BL/6 mice subcutaneously. Two weeks after tumor cell inoculation, mice were irradiated with a single-fraction 14-Gy dose of X-ray. One group of irradiated mice was immunized with an alpha-viral vector vaccine, SFVeE6,7, and another group received daily injections of the CXCR4 antagonist AMD3100 (3 mg/kg -intraperitoneal (i.p.)). Seven days after irradiation, all animals underwent N-[11C]methyl-AMD3465 PET.

PET imaging showed N-[11C]methyl-AMD3465 uptake in the tumor of single-fraction irradiated mice was nearly 2.5-fold higher than in sham-irradiated tumors (1.07 ± 0.31 %ID/g vs. 0.42 ± 0.05 % ID/g,p< 0.01). The tumor uptake was further increased by 4-fold (1.73 ± 0.17 % ID/g vs 0.42 ± 0.05 % ID/g,p< 0.01) in mice treated with single-fraction radiotherapy in combination with SFVeE6,7 immunization. Administration of AMD3100 caused a 4.5-fold reduction in the tracer uptake in the tumor of irradiated animals (0.24 ± 0.1 % ID/g,p< 0.001), suggesting that tracer uptake is indeed due to CXCR4-mediated chemotaxis.

This study demonstrates the feasibility of N-[11C]methyl-AMD3465 PET imaging to monitor treatment-induced changes in the density of CXCR4 receptors in tumors and justifies further evaluation of CXCR4 as a potential imaging biomarker for evaluation of anti-tumor therapies.