Multimodel preclinical platform predicts clinical response of melanoma to immunotherapy.

Although immunotherapy has revolutionized cancer treatment, only a subset of patients demonstrate durable clinical benefit. Definitive predictive biomarkers and targets to overcome resistance remain unidentified, underscoring the urgency to develop reliable immunocompetent models for mechanistic assessment. Here we characterize a panel of syngeneic mouse models, representing a variety of molecular and phenotypic subtypes of human melanomas and exhibiting their diverse range of responses to immune checkpoint blockade (ICB).

T cell stemness and dysfunction in tumors are triggered by a common mechanism.

A paradox of tumor immunology is that tumor-infiltrating lymphocytes are dysfunctional in situ, yet are capable of stem cell-like behavior including self-renewal, expansion, and multipotency, resulting in the eradication of large metastatic tumors. We find that the overabundance of potassium in the tumor microenvironment underlies this dichotomy, triggering suppression of T cell effector function while preserving stemness. High levels of extracellular potassium constrain T cell effector programs by limiting nutrient uptake, thereby inducing autophagy and reduction of histone acetylation at effector and exhaustion loci, which in turn produces CD8 T cells with improved in vivo persistence, multipotency, and tumor clearance.

Mono-, di- and trisubstituted derivatives of eflornithine: synthesis for in vivo delivery of DL-alpha-difluoromethylornithine in plasma.

The aim of this study was to synthesize a series of mono-, di- and trisubstituted derivatives of the human African trypanosomiasis drug eflornithine (alpha-difluoromethylornithine, DMFO, CAS 70052-12-9) to determine their partition coefficients, and to assess whether they deliver the parent drug in the plasma. If increased plasma concentrations of eflornithine could be achieved in this way, an oral dosage form would be possible. The derivatives, nine in total, were successfully synthesized by multi-step derivatisation of eflornithine on either its alpha-carboxylic or/and alpha-amino or/and delta-amino groups by either esterification or/and amidation or/and carbamylation, and their structures confirmed by NMR and MS spectroscopy.

Opposing contributions of polynucleotide phosphorylase and the membrane protein NlpI to biofilm formation by Salmonella enterica serovar Typhimurium.

CsgD and cyclic-3',5'-di-guanylate are key regulators of biofilm formation in Salmonella enterica serovar Typhimurium. Our results show that polynucleotide phosphorylase and NlpI oppositely altered expression of CsgD. Polynucleotide phosphorylase and NlpI also had opposite effects on the expression of yjcC, which codes for a cyclic-3',5'-di-guanylate phosphodiesterase affecting CsgD expression.