Engineering bacteria for targeted delivery of Lon protease to mediate c-MYC degradation in cancer therapy

• 1、School of biomedical sciences,Hunan University,Hunan changsha 410082

Abstract：Abstract: In recent years, engineered bacteria have emerged as promising tumor-targeted delivery systems for cancer therapy. Lon protease is a highly conserved ATP-dependent serine protease that has been reported to degrade the oncogenic protein c-MYC, suggesting its potential role in tumor suppression. In this study, Salmonella typhimurium with tumor-targeting capability was used as a delivery vector to construct a Lon protease-overexpressing engineered strain, SLpLon, and its expression characteristics and anti-tumor effects in vitro were preliminarily evaluated. The recombinant plasmid pBAD-pelB-Lon-HA was constructed using seamless cloning and transformed into the 14028S-ΔppGpp strain to obtain the engineered bacterium. Western blot analysis confirmed that Lon protease could be stably expressed and secreted under L-arabinose induction. Growth curve analysis indicated that overexpression of Lon protease had minimal impact on bacterial growth. In vitro experiments showed that bacterial lysates containing Lon protease inhibited the proliferation and colony formation of SK-MEL28 cells. In addition, decreased c-MYC protein levels were observed inSK-MEL28 cells after treatment. These findings suggest that Lon protease may suppress tumor cell proliferation by regulating c-MYC protein levels. This study provides an experimental basis for developing engineered bacteria-based delivery strategies for Lon protease in cancer therapy.

Keywords： Molecular Medicine Engineered bacteria Salmonella Lon protease c-MYC