TNFalpha gene delivery therapy for solid tumors

Antitumor in situ vaccination effect of TNFα and IL-12 plasmid DNA electrotransfer in a murine melanoma model

Gene electrotransfer (GET) is one of the most efficient non-viral gene therapy approaches for the localized transfer of multiple genes into tumors in vivo; therefore, it is especially promising for delivering different cytokines that are toxic if administered systemically. In this study, we used concomitant intratumoral GET of two cytokines: tumor necrosis factor alpha (TNFα), a potent cytotoxic cytokine to induce in situ vaccination, and interleukin 12 (IL-12), an immunostimulatory cytokine to boost the primed local immune response into a systemic one. After performing GET in murine melanoma tumors, both TNFα and IL-12 mRNA levels were significantly increased, which resulted in a pronounced delay in tumor growth of 27 days and a prolonged survival time of mice. An antitumor immune response was confirmed by extensive infiltration of immune cells in the tumor site, and expansion of the effector immune cells in the sentinel lymph nodes. Furthermore, the effect of in situ vaccination was indicated by the presence of vitiligo localized to the treatment area and resistance of the mice to secondary challenge with tumor cells. Intratumoral GET of two cytokines, one for in situ vaccination and one for an immune boost, proved feasible and effective in eliciting a potent and durable antitumor response; therefore, further studies of this approach are warranted.

Tumor Necrosis Factor (TNF) and Chemokines in Colitis-Associated Cancer

The connection between inflammation and tumorigenesis has been well established, based on a great deal of supporting evidence obtained from epidemiological, pharmacological, and genetic studies. One representative example is inflammatory bowel disease, because it is an important risk factor for the development of colon cancer. Moreover, intratumoral infiltration of inflammatory cells suggests the involvement of inflammatory responses also in other forms of sporadic as well as heritable colon cancer. Inflammatory responses and tumorigenesis activate similar sets of transcription factors such as NF-κB, Stat3, and hypoxia inducible factor and eventually enhances the expression of inflammatory cytokines including tumor necrosis factor (TNF) and chemokines. The expression of TNF and chemokines is aberrantly expressed in a mouse model of colitis-associated carcinogenesis as well as in inflammatory bowel disease and colon cancer in humans. Here, after summarizing the presumed actions of TNF and chemokines in tumor biology, we will discuss the potential roles of TNF and chemokines in chronic inflammation-associated colon cancer in mice.