An enzyme activated fluorescent probe for LTA4H activity sensing and its application in cancer screening

Early diagnosis of cancer is an efficient strategy to prevent tumor progression and improve the survival rate of patients. However, to discovery of reliable tumor-specific biomarkers remains a great challenge. Leukotriene A4 hydrolase (LTA4H) is a bifunctional zinc metalloenzyme with epoxide hydrolase activity and aminopeptidase activity, which plays important roles in allergic and inflammatory reactions and showed strong relevance with carcinoma progression. We thus sought to investigate the possibility of application LTA4H activity detection in cancer diagnosis. To achieve this, we herein develop an enzyme activated fluorescent probe for LTA4H activity sensing by incorporating the specific recognition unit of LTA4H with a red-emitting fluorophore. The acquired probe (named as ADMAB) showed high sensitivity and specificity toward LTA4H in vitro. By further application of ADMAB in living cells, significantly elevated LTA4H activity in cancer cell lines was observed when compared with normal cell lines and in vivo tracing A549 tumor in nude mice was also realized by ADMAB. Meanwhile, the wound-healing assay further revealed the importance of LTA4H in tumor metastasis. Moreover, the LTA4H activity in human serum sample was successfully detected by ADMAB and significantly elevated LTA4H activity in patients diagnosed with cancer was firstly found, which demonstrated ADMAB to be a useful tool for cancer diagnosis and LTA4H related biological study.