Synthesis and preliminary exploration of a NIR fluorescent probe for the evaluation of androgen dependence of prostate cancer

Purpose Castration resistance prostate cancer patients showing resistance to the androgen deprivation therapy always have low five-year survival rate and worse prognosis. A responsive NIR fluorescent probe was designed to report the androgen dependence and monitor the development of castration resistance for prostate cancer. Methods Intratumoral H2S in prostate cancer was closely related to castration resistance. A H2S-responsive NIR probe (HM) was developed as a dependent indicator to report the androgen dependence of prostate cancer. The specificity of HM to H2S and the influence of normal intracellular substrates to the response between H2S and HM were determined. Cell/in vivo animal imaging were performed on PC-3 and LnCAP cell/tumor bearing mice, which presented with androgen independence and androgen dependence, respectively. Results When HM responded to H2S, strong fluorescence at 770 nm could be rapidly turned on in 5 min with the stokes shift as large as 200 nm. The recognition between HM and H2S showed high specificity. Neither other common substrates showed capacity to turn on HM's fluorescence, nor their existence demonstrated competition. The fluorescence intensity was linearly dependent to the H2S concentration and the limited of detection was 0.15 μM. When HM was applied to PC-3/LNCaP prostate cancer cell and tumor, the intracellular and intratumoral H2S could be clearly imaged and monitored. Conclusion HM showing obvious fluorescent behaviors in androgen dependence and independence prostate tumor, which could work as an indicator to reported the androgen dependence of prostate cancer and monitor the development of castration resistance.