Steering CAR T cell epigenetic programs by tweaking manufacturing protocol.

CAR T cell persistence remains a significant roadblock to effective clinical translation of CAR T cells for solid and brain tumors. Jung et al.1 demonstrate enrichment of resident memory phenotypes through simple changes to the CAR T cell manufacturing process.

Diquinol Functionality Boosts the Superoxide Dismutase Mimicry of a Zn(II) Complex with a Redox-Active Ligand while Maintaining Catalyst Stability and Enhanced Activity in Phosphate Solution.

In the current work, we demonstrate ligand design concepts that significantly improve the superoxide dismutase (SOD) activity of a zinc complex; the catalysis is enhanced when two quinol groups are present in the polydentate ligand. We investigate the mechanism through which the quinols influence the catalysis and determine the impact of entirely removing a chelating group from the original hexadentate ligand. Our results suggest that SOD mimicry with these compounds requires a ligand that coordinates Zn(II) strongly in both its oxidized and reduced forms and that the activity proceeds through Zn(II)-semiquinone complexes. The complex with two quinols displays greatly enhanced catalytic ability, with the activity improving by as much as 450% over a related complex with a single quinol. In the reduced form of the diquinol complex, one quinol appears to coordinate to the zinc much more weakly than the other. We believe that superoxide can more readily displace this portion of the ligand, facilitating its coordination to the metal center and thereby hastening the SOD reactivity. Despite the presence of two redox-active groups that may communicate through intramolecular hydrogen bonding and redox tautomerism, only one quinol undergoes two-electron oxidation to a para-quinone during the catalysis. After the formation of the para-quinone, the remaining quinol deprotonates and binds tightly to the metal, ensuring that the complex remains intact in its oxidized state, thereby maintaining its catalytic ability. The Zn(II) complex with the diquinol ligand is highly unusual for a SOD mimic in that it performs more efficiently in phosphate solution.

Modulation of Hedgehog Signaling for the Treatment of Basal Cell Carcinoma and the Development of Preclinical Models.

Basal Cell Carcinoma (BCC) is the most commonly diagnosed cancer worldwide. While the survivability of BCC is high, many patients are excluded from clinically available treatments due to health risks or personal choice. Further, patients with advanced or metastatic disease have severely limited treatment options. The dysregulation of the Hedgehog (Hh) signaling cascade drives onset and progression of BCC. As such, the modulation of this pathway has driven advancements in BCC research. In this review, we focus firstly on inhibitors that target the Hh pathway as chemotherapeutics against BCC. Two therapies targeting Hh signaling have been made clinically available for BCC patients, but these treatments suffer from limited initial efficacy and a high rate of chemoresistant tumor recurrence. Herein, we describe more recent developments of chemical scaffolds that have been designed to hopefully improve upon the available therapeutics. We secondly discuss the history and recent efforts involving modulation of the Hh genome as a method of producing in vivo models of BCC for preclinical research. While there are many advancements left to be made towards improving patient outcomes with BCC, it is clear that targeting the Hh pathway will remain at the forefront of research efforts in designing more effective chemotherapeutics as well as relevant preclinical models.

Functional Disruption of Gli1-DNA Recognition via a Cobalt(III) Complex.

The aberrant activation of the Gli family of zinc finger transcription factors (ZFTFs) is associated with several types of human cancer, including medulloblastoma and basal cell carcinoma. We have reported the use of cobalt(III) Schiff-base complexes (Co(III)-sb) as potent inhibitors of ZFTFs in vivo. These complexes inhibit transcription by displacing the zinc finger domain's structural Zn(II) ion, destabilizing the alpha helix necessary for DNA recognition. Here, we describe the use of Co(III)-sb complexes for the selective inhibition of Gli1. Spectroscopic and computational studies of the Gli1 DNA binding domain found that Co(III)-sb displaced Zn(II) through direct coordination with the His residues of the Cys2 His2 Zn(II) binding site. As a result, there is a dose-dependent degradation of the alpha-helix content in the DNA binding domain of Gli1 and corresponding inhibition of consensus sequence recognition. We conclude that this strategy is well suited for the development of new and potent inhibitors of Gli1.

Delivery of Targeted Co(III)-DNA Inhibitors of Gli Proteins to Disrupt Hedgehog Signaling.

The Hedgehog (Hh) signaling pathway is integral for embryonic development and normal cell maintenance. However, aberrant expression of the Hh pathway is recognized as the oncogenic driving force for basal cell carcinoma (BCC). Current chemotherapeutic treatments that inhibit Hh signaling allow treatment of only locally advanced and metastatic BCCs via inhibition of the transmembrane protein, smoothened. It is further recognized that downstream mutations often lead to chemoresistant tumor recurrence. The Gli proteins are the ultimate regulators of Hh signaling and belong to a family of Cys2His2 zinc finger transcription factors (ZnFTFs) that we have shown can be irreversibly inhibited by a series of cobalt(III) Schiff base-DNA (CoSB-DNA) conjugates. However, a significant challenge is the delivery of CoSB-DNA complexes in mammalian tissues. Herein, we report a polyethyleneimine-functionalized graphene oxide nanoconjugate (GOPEI) that delivers CoGli, a CoSB-DNA complex that targets Gli specifically. We describe the characterization of the surface functionalization of GOPEI and accumulation in ASZ murine BCC cells via confocal microscopy and inductively coupled plasma-mass spectrometry (ICP-MS). Lysosomal escape of CoGli is further confirmed by confocal microscopy. We report the successful targeting of Gli by CoGli and a 17-fold improvement in potency over small-molecule Gli inhibitor GANT-61 in inhibiting Hh-driven migration of ASZ murine BCC cells. This study provides a promising starting point for further investigating CoGli inhibitors of Hh signaling in developed mammalian tissues.