The Synthesis And Their Applications Of Nile Blue Theranostic Reagents Based On Cancer-specific Enzymes

Cancer is a highly aggressive disease characterized by uncontrolled cell growth and cell division,and its morbidity and mortality have remained high.Early diagnosis and treatment of cancer can prolong the survival of more than 90% of cancer patients and is the key to cancer treatment.Traditional chemotherapy is currently the main means of clinical treatment of cancer,but its toxic side effects and inevitable drug resistance to normal tissues severely restrict its development.Fluorescent diagnostic reagents can simultaneously achieve fluorescence diagnosis and targeted therapy for cancer by combining anticancer drugs that target cancer cells and fluorescent molecules.Cancer markers,especially the cancer marker enzymes,which have high specificity and are high-efficiency targets for cancer treatment.Therefore,we design synthetic s based on cancer marker enzymes for fluorescence diagnosis and precision treatment of cancer.In this paper,a case of aminopeptidase N(APN)-activated fluorescent diagnostic reagent NBFMel was synthesized.The reagent is linked to the near-infrared(NIR)fluorophore Nile Blue and the APN-responsive melphalan prodrug p-fluorophenylalanyl-L-melphalan(J1)via flexible hexamethylenediamine.NBFMel itself has no fluorescence due to the intramolecular PET effect,and exhibits low toxicity.Once activated by APN,it can produce NIR fluorescence for the fluorescence diagnosis of cancer,and the release of the anticancer drug melphalan can kill cancer cells.Since NBFMel selectively targets cancer cells,it exhibits significant cytotoxicity against APN-positive cancer cells.More importantly,NBFMel can effectively cure the B16/BL6 tumor model without toxic side effects.This fluorescence theranostic reagent for APN response achieves the fluorescence "off-on" diagnostic signal and drug targeted release,providing a new idea for the design of diagnostic therapeutic reagents.In addition,a targeted diagnostic agent NBSNe based on the epidermal growth factor receptor EGFR was synthesized.The molecule links the thiosulfate Blue Nile photosensitizer EtNBS to the irreversible epidermal growth factor receptor(EGFR)inhibitor,nevatinib(Ne),via a flexible alkyl chain.Mediated by EGFR-TKI,NBSNe showed dark toxicity to wild mutant EGFR overexpressing cells and showed greater toxicity under illumination,while inhibiting the invasion and metastasis ability of cells.Based on photodynamic therapy(PDT),NBSNe reversed drug resistance in anti-EGFR-TKI cells.Through tail vein injection,NBSNe is enriched in the tumor site of mice,which significantly inhibits the growth of the 4T1 tumor model,and the drug does not bring obvious systemic toxicity to mice.The combination of photosensitizer and EGFR-TKI provides a new strategy for in vivo tumor diagnosis and biomarker-targeted local tumor chemotherapy.