The ZMAGE-A3 affitoxin 172-cpp has great potential for targeting therapy of tumors

Background The MAGE-A3 oncological antigen, a member of the cancer-testis protein family, is markedly overexpressed across various types of malignant tumors. Affibody molecules, a novel class of compact targeting proteins (~6.5 kDa), have been established as potent agents for molecular imaging and targeted cancer therapy. This study evaluates the designed an affibody molecules as novel agents by fusing a MAGE-A3 affibody molecule with modified Pseudomonas exotoxin (PE38KDEL) and a cell-penetrating peptide (cpp) to develop an affitoxin, ZMAGE-A3 affitoxin 172-cpp, and evaluated its anti-tumor efficacy. Methods we verified the expression of ZMAGE-A3 affitoxin 172-cpp by SDS-PAGE. MAGE-A3-positive cells was selected by qPCR. The internalization of ZMAGE-A3 affitoxin 172-cpp was detected using fluorescence imaging. Cell viability was detected using cell counting kit 8 (CCK-8) and colony formation assay. Cell apoptosis was measured by flow cytometry. The in vivo targeting ability of ZMAGE-A3 affitoxin 172-cpp was analyzed by near-infrared (NIR) imaging. Results ZMAGE-A3 affitoxin 172-cpp demonstrated precise binding to the MAGE-A3 protein in living cells. Moreover, the accumulation of DyLight755-labeled ZMAGE-A3 affitoxin 172-cpp in MAGE-A3-positive tumors was observed as early as 1 hour post-injection, with clearance by 48 hours. ZMAGE-A3 affitoxin 172-cpp effectively suppressed the viability and induced apoptosis of A375 and A2058 cells. The results from xenograft model indicated that ZMAGE-A3 affitoxin 172-cpp effectively repressed in vivo tumor growth. Conclusion Our findings support the potential of the ZMAGE-A3 affitoxin 172-cpp as a molecular imaging and therapeutic agent for MAGE-A3 positive cancer.