[Near-infrared fluorescent zinc-dipicolylamine: a new molecular imaging probe to monitor the efficiency of chemotherapy].

OBJECTIVE To investigate the feasibility of a novel molecular probe of Zn-DPA-PSS794 to monitor the efficiency of doxorubicin to ovarian cancer and compare with Cy5.5-annexin V. METHODS Efficiency of doxorubicin to OVCAR-8 cells in vitro was measured by MTT assay and flow cytometry. The in vivo studies were performed on an OVCAR-8 xenograft tumor model. Mice were divided into a control group and a treatment group. Each group was divided into 2 subgroups, DPA and annexin V. In the treatment group, the mice were treated with doxorubicin for 2 doses. All mice were performed optical imaging by Zn-DPA-PSS794 or Cy5.5-annexin V, respectively and then sacrificed. The tumor was separated and stained by HE. The expression of caspase-3 protein was measured by Western blot. RESULTS The IC50 of doxorubicin to OVCAR-8 was 6 μmol/L. The percentage of apoptosis and dead cells was 35% after doxorubicin treatment. In the optical image, photons accumulated in the tumor either by Zn-DPA-PSS794 or Cy 5.5-annexin V in the treatment group. That was negative in the control group. The fluorescence intensity had significant difference between the 2 groups(P<0.001). The nuclei were big and stained with deep color after the cells were stained with HE. The caspase-3 expression was high in the treatment group, while it was low in the control group. CONCLUSION Zn-DPA-PSS794 as a probe used by optical imaging can monitor the efficiency of doxorubicin to OVCAR-8 xenograft tumor, which is similar to Cy5.5-annexin V.