Abstract:

Objective To investigate the inhibitory effects of L. monocytogenes expressing melanoma- inhibiting activity （MIA） gene on malignant melanoma. Methods The plasmid pERL3-hly-MIA was constructed and used to transform live L. monocytogenes by electroporation. After culture, the transformed L. monocytogenes, namely LM-hly-MIA, was harvested for the detection of MIA protein by Western Blot. A total of 24 mice were divided into three groups, namely control group, LM group and LM-hly-MIA group, to be immunized with physiological saline, L. monocytogenes and LM-hly-MIA, respectively. One day after the immunization, mice were subcutaneously inoculated with 0.1 mL of B16 cells at a concentration of 1 × 107/mL. One week later, reimmunization was performed. The size and weight of tumors were observed and measured in these mice. Results Enzyme digestion and Western blot confirmed the successful construction of plasmid pERL3-hly-MIA. The average weight of tumors in mice was 4.33 ± 0.91 gram, 3.36 ± 0.41 gram and 1.89 ± 0.52 gram, respectively in the control group, LM group and LM-hly-MIA group, respectively （P < 0.05）, with the inhibition rates of tumor growth being 22.4% and 61.5% in LM group and LM-hly-MIA group, respectively. Conclusion The attenuated strain of L. monocytogenes expressing MIA gene could evidently inhibit melanoma growth.