HD-ALP fluorescent probe: a high-sensitivity tool for alkaline phosphatase imaging and preclinical diagnosis in three ovarian cancer models†

Ovarian cancer (OC) remains a prevalent gynecological malignancy, posing significant threats to women's health globally. Emerging evidence underscores the critical involvement of alkaline phosphatase (ALP) in OC pathogenesis, prompting the development of targeted diagnostic tools. Herein, we report the successful application of a novel fluorescent probe, HD-ALP, for fluorescence imaging of ALP in ovarian cancer cells and preclinical models. After being triggered by ALP, HD-ALP responded in the fluorescence signal reporting manner. More importantly, the fluorescence signal showed a reliable linear correlation with ALP levels in the range of 0–10 000 U L⁻¹. The HD-ALP probe demonstrated high sensitivity, selectivity, and stability under necessary biological conditions. The intracellular imaging results indicated that HD-ALP enabled the visualization of ALP levels within ovarian cancer cells. The in vivo experiments demonstrated that HD-ALP could accurately differentiate between healthy and cancerous models (subcutaneous transplantation tumor model of ovarian cancer, orthotopic ovarian cancer model, and primary ovarian cancer model). Notably, in cellular and in vivo imaging, HD-ALP could effectively reflect the decrease in the fluorescence signal after the addition of ALP inhibitors. By integrating ALP detection, which utilizes the HD-ALP fluorescence mode, with traditional methods like immunohistochemistry staining and serum biomarker detection, potential strategies for more accurate diagnosis of OC may be developed for preclinical trials in the future. According to the research, this is also one of the few developments of fluorescence detection tools for measuring ALP levels in ovarian cancer models.