Inhibiting the MNK1/2-eIF4E axis impairs melanoma phenotype switching and potentiates antitumor immune responses.

Melanomas commonly undergo a phenotype switch, from a proliferative to an invasive state. Such tumor cell plasticity contributes to immunotherapy resistance; however, the mechanisms are not completely understood and thus are therapeutically unexploited. Using melanoma mouse models, we demonstrated that blocking the MNK1/2-eIF4E axis inhibited melanoma phenotype switching and sensitized melanoma to anti-PD-1 immunotherapy. We showed that phospho-eIF4E-deficient murine melanomas expressed high levels of melanocytic antigens, with similar results verified in patient melanomas. Mechanistically, we identified phospho-eIF4E-mediated translational control of NGFR, a critical effector of phenotype switching. Genetic ablation of phospho-eIF4E reprogrammed the immunosuppressive microenvironment, exemplified by lowered production of inflammatory factors, decreased PD-L1 expression on dendritic cells and myeloid-derived suppressor cells, and increased CD8+ T cell infiltrates. Finally, dual blockade of the MNK1/2-eIF4E axis and the PD-1/PD-L1 immune checkpoint demonstrated efficacy in multiple melanoma models regardless of their genomic classification. An increase in the presence of intratumoral stem-like TCF1+PD-1+CD8+ T cells, a characteristic essential for durable antitumor immunity, was detected in mice given a MNK1/2 inhibitor and anti-PD-1 therapy. Using MNK1/2 inhibitors to repress phospho-eIF4E thus offers a strategy to inhibit melanoma plasticity and improve response to anti-PD-1 immunotherapy.

Detection of potential chronic kidney disease markers in breath using gas chromatography with mass-spectral detection coupled with thermal desorption method.

The analytical potential of chromatographic breath analysis towards detection of compounds suggested as markers of chronic kidney disease (CKD) was tested. Until now, trimethylamine (TMA) considered as a potential marker of renal disorder was detected mainly in plasma. Detection of TMA in breath was rarely undertaken due to analytical difficulties associated with amines' properties. The results of our investigations confirmed that an application of thermal desorption (TD) and gas chromatography with mass-spectral detection (GC/MS) allows direct detection of TMA in breath. The preliminary studies allowed to determine the breath composition in case of patients suffering from CKD and to compare the obtained results to a control group. Breath samples were collected from 14 patients and 9 healthy volunteers. TMA was detected in all patients suffering from CKD in the range 1.76-38.02ppb, but not in the control group. Acetone and isoprene were present in the exhaled air of all examined persons. The concentration of acetone was in the range of 26.52-329.46ppb in the patient group and 73.11-437.14ppb in the control group. Isoprene was detected in the range 57.17-329.8ppb among CKD patients and 27.99-143.77ppb in healthy volunteers. Additionally aliphatic hydrocarbons and sulfur compounds were determined in breath as compounds which could be essential in case of diseases coexisting with CKD. Apart from TMA and pentane no statistically significant differences were found using our analytical technique. TMA was detected in the breath of all patients with CKD and in none of breath samples in control group. TMA seems to be a promising marker of CKD.

[New opportunities of renal diseases diagnostics using gas chromatography]. / Nowe mozliwosci diagnostyki chorób nerek przy wykorzystaniu chromatografii gazowej.

During the last decade the amount of patients suffering from chronic kidney disease (CKD) has increased. The physicians' efforts are focused on early CKD diagnosis and reduction of the end-stage renal diseases incidence. The breath test seems to be a promising diagnostic device offering early noninvasive diseases detection. The aim of presented study was the determination of breath composition in case of persons suffering from CKD. Breath samples were collected from 14 patients and 7 healthy volunteers. Exhaled air samples were analyzed by gas chromatography equipped with mass spectrometer (GC-MS). Samples were enriched using solid phase microextraction (SPME). Trimethylamine (TMA), mentioned in literature as potential marker of chronic kidney diseases, was detected in case of 11 patients. Among breath components were detected: sulfur compounds: dimethyl sulfide (was detected in exhaled air of patients and control group), carbon disulfide (was detected in case of 4 healthy and in case of all patients) and also potential markers of oxidative stress: propane, butane, pentane, 2-methylpentane, hexane. Acetone and isoprene occurred in exhaled air of all studied persons. The considerable increase of acetone concentration in comparison to control group was observed in case of patients with diagnosed diabetes. The application of gas chromatography with mass spectrometer and appropriate enrichment of samples allows to define the breath profile characteristic for chosen the unit of disease. Typical compounds--biomarkers can be useful for early diagnostics.