64Cu/68Ga Labelled EB-ss-CPT PET/CT Scan in Colorectal Cancer

CPT, a botanical anticancer drug, is a mechanism that inhibits DNA synthesis and thus exerts anticancer effects by using topoisomerase I as its target of action, and has shown good efficacy in digestive system tumors and head and neck tumors, etc. Previous research result showed that amphiphilic EB-ss-CPT formed nanoparticles by self-assembly, bound to albumin in vivo and released CPT by breaking disulfide bonds under high GSH conditions in tumor tissues, effectively enhancing the pharmacokinetics and biodistribution of camptothecin, thereby improving therapeutic efficacy and In this study, the sensitivity of colorectal cancer cells to the drug was also demonstrated. In this study, 64Cu-NOTA-EB-ss-CPT (hereafter 64Cu-EB-CPT) was generated by posionuclide 64Cu-labelled EB-ss-CPT for PET/CT imaging alone and showed better tumour enrichment compared to the 64Cu-labelled CPT group. EB-CPT is expected to be more enriched in tumour tissue through the EPR effect of its nanoparticles, and 64Cu is also a promising radionuclide for quantitative analysis using PET/CT imaging. The formation of 64Cu-EB-CPT or 68Ga-EB-CPT by labelling EB-CPT with the positronium nuclide 64Cu or 68Ga is expected to be enhanced by the EPR effect of the precursors (the enhanced permeability and retention effect of solid tumours). The EPR effect (enhanced permeability and retention effect) refers to the tendency of molecules or particles of certain sizes to accumulate in tumour tissue relative to normal tissue) is expected to enrich the drug in the tumour area and allow early diagnosis of tumour patients by PET/CT imaging with the preceding positronuclide 64Cu or 68Ga, which can help in the staging of tumours and the development of treatment plans.