Generation and Characterization of Torudokimab (LY3375880): A Monoclonal Antibody That Neutralizes Interleukin-33

Background

Interleukin-33 (IL-33) is an alarmin that is released following cellular damage, mechanical injury, or necrosis. It is a member of the IL-1 family and binds to a heterodimer receptor consisting of ST2 and IL-1RAP to induce the production of a wide range of cellular mediators, including the type 2 cytokines IL-4, IL-5 and IL-13. This relationship has led to the hypothesis that the IL-33/ST2 pathway is a driver of allergic disease and inhibition of the IL-33 and ST2 association could have therapeutic benefit.

Methods

In this paper, we describe the selection of a phage antibody through the ability to bind human IL-33 and block IL-33/ST2 interaction. This hit antibody was then affinity matured by site-directed mutagenesis of the antibody complementarity-determining regions (CDRs). Further characterization of a fully human monoclonal antibody (mAb), torudokimab (LY3375880) included demonstration of human IL-33 neutralization activity in vitro with an NFκB reporter assay and IL-33 induced mast cell cytokine secretion assay, followed by an in vivo IL-33-induced pharmacodynamic inhibition assay in mice that used IL-5 production as the endpoint.

Results

Torudokimab is highly specific to IL-33 and does not bind any of the other IL-1 family members. Furthermore, torudokimab binds human and cynomolgus monkey IL-33 with higher affinity than the binding affinity of IL-33 to ST2, but does not bind mouse, rat, or rabbit IL-33. Torudokimab’s half-life in cynomolgous monkey projects monthly dosing in the clinic.

Conclusion

Due to torudokimab’s high affinity, its ability to completely neutralize IL-33 activity in vitro and in vivo, and the observed cynomolgus monkey pharmacokinetic properties, this molecule was selected for clinical development.

Knockdown of cancer testis antigens modulates neural stem cell marker expression in glioblastoma tumor stem cells

The cancer stem cell hypothesis posits that a subpopulation of cancer stem cells is frequently responsible for a tumor's progression and resistance to treatment. The differential cellular morphology and gene expression between cancer stem cells and the majority of the tumor is becoming a point of attack for research into the next generation of therapeutic agents that may work through an induction of differentiation rather than apoptosis. Advances in the field of high-content imaging (HCI), combined with modern shRNA technology and subpopulation analysis tools, have created an ideal screening system to detect these morphological changes in a subset of cells upon gene knockdown. The authors examined several glioblastoma stem cell isolates pre- and postdifferentiation to elucidate the phenotypic effects caused by both serum differentiation and gene knockdown. Neural markers were first characterized in these cells at varying states of differentiation using HCI and immunoblots. The authors then chose one of these isolates, in both the pre- and postdifferentiated forms, for further analysis and screened for morphological changes upon shRNA knockdown of a panel of cancer testis antigens (CTAs). CTAs are a family of proteins that are normally expressed in male germ cells as well as heterogeneously expressed in some metastatic tumors. This gene family has also been implicated in the differentiation of normal human stem cells, therefore making it an ideal candidate for modulation in tumor stem cells. Using their approach, the authors identified the differential effects of gene knockdown in both cell types leading to either changes in neural stem cell marker expression or a decreased cell density likely due to growth arrest or cell death. The resolution that HCI brings to a screen at the subpopulation level makes it an excellent tool for the analysis of phenotypic changes induced by shRNA knockdown in a variety of tumor stem cells.

Growth retardation and increased apoptosis in mice with homozygous disruption of the Akt1 gene

The serine/threonine kinase Akt has been implicated in the control of cell survival and metabolism. Here we report the disruption of the most ubiquitously expressed member of the akt family of genes, akt1, in the mouse. Akt1(-/-) mice are viable but smaller when compared to wild-type littermates. In addition, the life span of Akt1(-/-) mice, upon exposure to genotoxic stress, is shorter. However, Akt1(-/-) mice do not display a diabetic phenotype. Increased spontaneous apoptosis in testes, and attenuation of spermatogenesis is observed in Akt1(-/-) male mice. Increased spontaneous apoptosis is also observed in the thymi of Akt1(-/-) mice, and Akt1(-/-) thymocytes are more sensitive to apoptosis induced by gamma-irradiation and dexamethasone. Finally, Akt1(-/-) mouse embryo fibroblasts (MEFs) are more susceptible to apoptosis induced by TNF, anti-Fas, UV irradiation, and serum withdrawal.

Heteronuclear nuclear magnetic resonance assignments, structure and dynamics of SUMO-1, a human ubiquitin-like protein

The structure of a ubiquitin-like protein, small ubiquitin-related modifier-1 (SUMO-1), was earlier determined using homonuclear nuclear magnetic resonance (NMR) spectroscopy, since the spectral quality of the protein was not suitable for heteronuclear NMR data collection. In this study, a slightly different construct of the SUMO-1 gene was used for protein over-expression. The protein purified from this construct showed high spectral qualities, therefore, multi-dimensional heteronuclear NMR data for a dynamic study and structural determination were acquired. The structure of SUMO-1 obtained in this study differs in several respects from the structure obtained from homonuclear NMR data. Furthermore, structural differences were observed between the new SUMO-1 and ubiquitin structures. These differences may be important for SUMO-1-specific recognition in cells. Additionally, relaxation parameters indicate that SUMO-1 undergoes highly anisotropic tumbling in solution and that the long amino (N)-terminal sequence of SUMO-1 is highly dynamic with increasing flexibility towards the end.

A winged helix protein from yeast Saccharomyces cerevisiae recognizes centromere sequences

The winged helix-turn-helix motif was initially identified in the mammalian hepatocyte-enriched transcription factor HNF-3 and the Drosophila forkhead homeotic protein. Proteins containing the winged helix motif have been shown to play important roles in tissue-specific developmental regulation. In this report, by using a genomic binding site selection method, we demonstrate that the winged helix protein YFKH-1 from the yeast Saccharomyces cerevisiae recognizes conserved sequence in yeast centromeres. Thus, our data suggest that the winged helix proteins of the yeast may be involved in centromeric functions of the yeast.

The dissociation rate of a winged helix protein-DNA complex is influenced by non-DNA contact residues

The dissociation constants and the half-lives of the DNA complexes of winged helix protein Genesis and its mutants were investigated. Our data show that substitutions of non-DNA contact residues in the two highly dynamic wing sequences dramatically change the off rates of the complexes. Thus, our data indicate that the off rate of a DNA complex is encoded in the amino acid sequence of the DNA-binding protein and/or should be a unique property for a protein-DNA complex. Our data also indicate that the local structural transition of a DNA-binding protein in its DNA recognition process is likely to go through a transition state, which can control the on and off rates of a complex.

Different DNA contact schemes are used by two winged helix proteins to recognize a DNA binding sequence

The hepatocyte nuclear factor 3 (HNF-3)/fork head (fkh) family contains a large number of transcription factors which recognize divergent DNA sequences via a winged-helix binding motif. In this report we present studies on the DNA binding properties of winged-helix HNF-3/fkh homologues 1 (HFH-1) and 2 (HFH-2) which recognize a shared DNA binding site with different affinities. To explore how HFH-1 and HFH-2 proteins recognize this DNA binding sequence, the binding affinities of these two HFH proteins toward a series of DNA sites containing a single strand trimer loop insertion at different positions were studied. This insertion induces a bend of approximately 80 degrees in the DNA binding site (prebending). HFH-1 and HFH-2 were shown to recognize DNA sites prebent at many nucleotide positions on both strands of the DNA sequence. Both HFH-1 and HFH-2 were more sensitive to mismatch insertions on the sense strand of the DNA binding site, especially within the AAAATAAC sequence. Our data suggest that the recognition helix (helix 3) recognizes the AAAATAAC sequence and that the helix 3/DNA interaction results in bending of the DNA which narrows the major groove in the AAAATAAC sequence. Furthermore, the binding affinities of HFH-1 and HFH-2 toward DNA binding sites with base-pair reversion in the AAAATAAC sequence was also investigated. Different patterns of response from HFH-1 and HFH-2 to both prebent and base-pair reverted binding sites was observed. Our results demonstrate that even two highly conserved members of the winged-helix family may contact the same DNA sequence differently.