First-in-human stage III/IV melanoma​ clinical trial of immune priming agent IFx-Hu2.0.

IFx-Hu2.0 was designed to encode part of the Emm55 protein contained within a plasmid in a formulation intended for transfection into mammalian cells. IFx-Hu2.0 promotes both adaptive and innate immune responses in animal studies. Furthermore, previous studies have demonstrated safety/efficacy in equine, canine, and murine species. We present the first-in-human study of IFx-Hu2.0, administered by intralesional injection into melanoma tumors of seven patients with stage III/IV unresectable melanoma. No dose-limiting toxicities attributable to IFx-Hu2.0 were observed. Grade 1/2 injection site reactions were observed in five of seven patients. IgG and IgM responses were seen in the peripheral blood to Emm55 peptides and known melanoma antigens, suggesting that IFx-Hu2.0 acts as an individualized "in-situ vaccine." Three of four patients previously refractory to anti-PD1 experienced clinical benefit upon subsequent anti-PD1-based treatment. Therefore, this approach is feasible, and clinical/correlative outcomes warrant further investigation for treating metastatic melanoma patients as an immune priming agent.

Autologous tumor cells engineered to express bacterial antigens.

Cancer immunotherapies are emerging as promising treatment modalities in the management of the disease. As a result, cancer vaccines are considered to be immensely crucial in preventing recurrence, a well-known nemesis in cancer patients because they have the potential to activate memory antitumor immunity. Due to poor antigenicity and self-tolerance, most tumor antigens require interventional vaccine therapies to provide an adequate "danger" signal to the immune system in order to activate a robust, clinically meaningful antitumor immunity. It has been postulated that this requirement may be achieved by providing bacterial and/or viral immunogens to prime this type of immune response. Briefly, we provide here a method of transfecting whole tumor cells with plasmid DNA encoding an immunogenic bacterial protein such as Emm55, which was derived from Streptococcus pyogenes (S. pyogenes). Subsequent inactivation of the transfected cells by irradiation (100 Gray) prevents replication. This type of whole-cell vaccine, e.g., ImmuneFx™, has demonstrated activity in a murine neuroblastoma model, in canine lymphoma patients with naturally occurring disease, and in many cancer types in companion animals. The protocols described in this chapter provide the necessary materials and methodologies to manufacture such a vaccine.

Improving 1,3-propanediol production from glycerol in a metabolically engineered Escherichia coli by reducing accumulation of sn-glycerol-3-phosphate.

High levels of glycerol significantly inhibit cell growth and 1,3-propanediol (1,3-PD) production in anaerobic glycerol fermentation by genetically engineered Escherichia coli (E. coli) strains expressing genes from the Klebsiella pneumoniae dha (K.pneumoniae) regulon. We have previously demonstrated that 1,3-PD production by the engineered E. coli can be improved by reducing the accumulation of methylglyoxal. This study focuses on investigation of another lesser-known metabolite in the pathways related to 1,3-PD production-glycerol-3-phosphate (G3P). When grown anaerobically on glycerol in the absence of an exogenous acceptor, the engineered E. coli strains have intracellular G3P levels that are significantly higher than those in K. pneumoniae, a natural 1,3-PD producer. Furthermore, in the engineered E. coli strains, the G3P levels increase with increasing glycerol concentrations, whereas, in K. pneumoniae, the concentrations of G3P remain relatively constant. Addition of fumarate, which can stimulate activity of anaerobic G3P dehydrogenase, into the fermentation medium led to a greater than 30-fold increase in the specific activity of anaerobic G3P dehydrogenase and a significant decrease in concentrations of intracellular G3P and resulted in better cell growth and an improved production of 1,3-PD. This indicates that the low activity of G3P dehydrogenase in the absence of an exogenous electron acceptor is one of the reasons for G3P accumulation. In addition, spent media from E.coli Lin61, a glycerol kinase (responsible for conversion of glycerol to G3P) mutant, contains greatly decreased concentrations of G3P and shows improved production of 1,3-PD (by 2.5-fold), when compared to media from its parent strain E. coli K10. This further suggests that G3P accumulation is one of the reasons for the inhibition of 1,3-PD production during anaerobic fermentation.