Preferential proliferation of attenuated Salmonella typhimurium within neuroblastoma.

Background/purpose: Attenuated Salmonella typhimurium, a facultative intracellular parasite that colonizes the liver, has been shown to accumulate within extrahepatic malignancies. The authors sought to define a mechanism for attenuated Salmonella accumulation within cancer cells compared with hepatocytes.

Methods: Invasion and intracellular proliferation of attenuated Salmonella was assessed through an in vitro assay performed on neuroblasoma, osteosarcoma, hepatoma, and colon adenocarcinoma cell lines and compared with freshly isolated mouse hepatocytes.

Results: The efficiency of attenuated S typhimurium invasion into hepatocytes was greater than any malignant cell line (3.8 v 0.46; P <.04). However, the intracellular proliferation of the bacteria was most abundant within neuroblastoma, exceeding the proliferation within hepatocytes (14.3 v 6.2; P <.01).

Conclusions: Attenuated S typhimurium may prove to be an effective in vivo immunotherapy for the local delivery of therapeutic proteins to neuroblastoma.