Context-dependent activation of STING-interferon signaling by CD11b agonists enhances anti-tumor immunity

Chronic activation of inflammatory pathways and suppressed interferon are hallmarks of immunosuppressive tumors. Previous studies have shown that CD11b integrin agonists could enhance anti-tumor immunity through myeloid reprograming, but the underlying mechanisms remain unclear. Herein we find that CD11b agonists alter tumor-associated macrophage (TAM) phenotypes by repressing NF-κB signaling and activating interferon gene expression simultaneously. Repression of NF-κB signaling involves degradation of p65 protein and is context independent. In contrast, CD11b agonism induces STING/STAT1 pathway-mediated interferon gene expression through FAK-mediated mitochondrial dysfunction, with the magnitude of induction dependent on the tumor microenvironment and amplified by cytotoxic therapies. Using tissues from phase I clinical studies, we demonstrate that GB1275 treatment activates STING and STAT1 signaling in TAMs in human tumors. These findings suggest potential mechanism-based therapeutic strategies for CD11b agonists and identify patient populations more likely to benefit.

Molecular characterization of type I IFN-induced cytotoxicity in bladder cancer cells reveals biomarkers of resistance

Although anti-tumor activities of type I interferons (IFNs) have been recognized for decades, the molecular mechanisms contributing to clinical response remain poorly understood. The complex functions of these pleiotropic cytokines include stimulation of innate and adaptive immune responses against tumors as well as direct inhibition of tumor cells. In high-grade, Bacillus Calmette-Guérin (BCG)-unresponsive non-muscle-invasive bladder cancer, nadofaragene firadenovec, a non-replicating adenovirus administered locally to express the IFNα2b transgene, embodies a novel approach to deploy the therapeutic activity of type I IFNs while minimizing systemic toxicities. Deciphering which functions of type I IFN are required for clinical activity will bolster efforts to maximize the efficacy of nadofaragene firadenovec and other type I IFN-based therapies, and inform strategies to address resistance. As such, we characterized the phenotypic and molecular response of human bladder cancer cell lines to IFNα delivered in multiple contexts, including adenoviral delivery. We found that constitutive activation of the type I IFN signaling pathway is a biomarker for resistance to both transcriptional response and direct cytotoxic effects of IFNα. We present several genes that discriminate between sensitive and resistant tumor cells, suggesting they should be explored for utility as biomarkers in future clinical trials of type I IFN-based anti-tumor therapies.

Metabolic engineering of Escherichia coli for direct production of 1,4-butanediol

1,4-Butanediol (BDO) is an important commodity chemical used to manufacture over 2.5 million tons annually of valuable polymers, and it is currently produced exclusively through feedstocks derived from oil and natural gas. Herein we report what are to our knowledge the first direct biocatalytic routes to BDO from renewable carbohydrate feedstocks, leading to a strain of Escherichia coli capable of producing 18 g l(-1) of this highly reduced, non-natural chemical. A pathway-identification algorithm elucidated multiple pathways for the biosynthesis of BDO from common metabolic intermediates. Guided by a genome-scale metabolic model, we engineered the E. coli host to enhance anaerobic operation of the oxidative tricarboxylic acid cycle, thereby generating reducing power to drive the BDO pathway. The organism produced BDO from glucose, xylose, sucrose and biomass-derived mixed sugar streams. This work demonstrates a systems-based metabolic engineering approach to strain design and development that can enable new bioprocesses for commodity chemicals that are not naturally produced by living cells.

Global analysis of host response to induction of a latent bacteriophage

BACKGROUND

The transition from viral latency to lytic growth involves complex interactions among host and viral factors, and the extent to which host physiology is buffered from the virus during induction of lysis is not known. A reasonable hypothesis is that the virus should be evolutionarily selected to ensure host health throughout induction to minimize its chance of reproductive failure. To address this question, we collected transcriptional profiles of Escherichia coli and bacteriophage lambda throughout lysogenic induction by UV light.

RESULTS

We observed a temporally coordinated program of phage gene expression, with distinct early, middle and late transcriptional classes. Our study confirmed known host-phage interactions of induction of the heat shock regulon, escape replication, and suppression of genes involved in cell division and initiation of replication. We identified 728 E. coli genes responsive to prophage induction, which included pleiotropic stress response pathways, the Arc and Cpx regulons, and global regulators crp and lrp. Several hundred genes involved in central metabolism, energy metabolism, translation and transport were down-regulated late in induction. Though statistically significant, most of the changes in these genes were mild, with only 140 genes showing greater than two-fold change.

CONCLUSION

Overall, we observe that prophage induction has a surprisingly low impact on host physiology. This study provides the first global dynamic picture of how host processes respond to lambda phage induction.

Global analysis of host response to induction of a latent bacteriophage

Background

The transition from viral latency to lytic growth involves complex interactions among host and viral factors, and the extent to which host physiology is buffered from the virus during induction of lysis is not known. A reasonable hypothesis is that the virus should be evolutionarily selected to ensure host health throughout induction to minimize its chance of reproductive failure. To address this question, we collected transcriptional profiles of Escherichia coli and bacteriophage lambda throughout lysogenic induction by UV light.

Results

We observed a temporally coordinated program of phage gene expression, with distinct early, middle and late transcriptional classes. Our study confirmed known host-phage interactions of induction of the heat shock regulon, escape replication, and suppression of genes involved in cell division and initiation of replication. We identified 728 E. coli genes responsive to prophage induction, which included pleiotropic stress response pathways, the Arc and Cpx regulons, and global regulators crp and lrp. Several hundred genes involved in central metabolism, energy metabolism, translation and transport were down-regulated late in induction. Though statistically significant, most of the changes in these genes were mild, with only 140 genes showing greater than two-fold change.

Conclusion

Overall, we observe that prophage induction has a surprisingly low impact on host physiology. This study provides the first global dynamic picture of how host processes respond to lambda phage induction.