Antibiotic use reduces efficacy of tyrosine kinase inhibitors in patients with advanced melanoma and non-small-cell lung cancer.

BACKGROUND: Antibiotic (ABX) use can reduce the efficacy of immune checkpoint inhibitors and chemotherapeutics. The effect for patients treated with targeted therapies, namely, small-molecule tyrosine kinase inhibitors (TKIs), is less known. PATIENTS AND METHODS: Retrospective data were analysed for TKI-treated patients with advanced melanoma and non-small-cell lung cancer (NSCLC) between January 2015 and April 2017 at The Christie NHS Foundation Trust. Data on demographics, disease burden, lactate dehydrogenase (LDH) level, presence of brain metastases, ECOG performance status (PS) and ABX use were collected. Progression-free survival (PFS) and overall survival (OS) were compared between the ABX+ group (ABX within 2 weeks of TKI initiation-6 weeks after) and the ABX- group (no ABX during the same period). RESULTS: A total of 168 patients were included; 89 (53%) with NSCLC and 79 (47%) with melanoma. 55- (33%) patients received ABX. On univariable analysis, ABX+ patients demonstrated shorter PFS (208 versus 357 days; P = 0.008) and OS (294 versus 438 days; P = 0.024). Increased age, poorer PS and higher LDH were associated with shorter PFS and OS. On multivariable analysis, ABX use was independently associated with shorter PFS [hazard ratio (HR) 1.57, 95% confidence interval (CI) 1.05-2.34, P = 0.028] and OS (HR 2.19, 95% CI 1.44-3.32, P = 0.0002). The negative impact of ABX on OS was particularly pronounced for patients with PS of ≥2 (HR 3.82, 95% CI 1.18-12.36, P = 0.025). CONCLUSION: For patients treated with TKIs, ABX use is independently associated with reduced PFS and OS and judicious use is warranted, particularly in patients with poorer PS.

Investigation of mitochondrial protein expression and oxidation in heart muscle in low and high feed efficient male broilers in a single genetic line.

The objective of this study was to assess the expression of mitochondrial proteins and oxidized proteins in heart muscle homogenate obtained from male broilers exhibiting either high or low feed efficiency (G:F) phenotypes. Tissue homogenate was prepared from ventricular tissue obtained from broilers with high (0.80+/-0.01, n=8) and low (0.62+/-0.02, n=8) FE. The levels of specific immunoreactive proteins and oxidized proteins (carbonyls) were determined using Western blot analysis. The expression of 6 electron transport chain proteins [complex II, 70S subunit (CII 70S); iron-sulfur-containing protein (ISP), cytochrome b (Cyt b), cytochrome (Cyt c1) (of complex III); and cytochrome oxidase subunit II (COX II) (of complex IV)] and adenine nucleotide translocator 1 (ANT1) were higher in low feed efficiency heart mitochondria, but 1 protein [NAD subunit 6c (NAD6c) (complex I)] was higher in high feed efficiency birds. Protein carbonyl levels, indicative of oxidized proteins, were higher in heart tissue of low compared with high feed efficiency broilers.

Membrane potential and H2O2 production in duodenal mitochondria from broiler chickens (Gallus gallus domesticus) with low and high feed efficiency.

Increased hydrogen peroxide (H2O2) production was observed in duodenal mitochondria obtained from broiler chickens with low feed efficiency (FE). As a decrease in mitochondrial membrane potential (Deltapsi(m)) due to mild uncoupling of oxidative phosphorylation reduces reactive oxygen species production, this study was conducted to evaluate the effect of uncoupling on Deltapsi(m) and H2O2 production in duodenal mitochondria isolated from broilers with low (0.48+/-0.02) and high (0.68+/-0.01) FE. Membrane potential and H2O2 production were measured fluorometrically and in the presence of different levels of an uncoupler, carbonylcyanide-p-trifluoromethoxyphenylhydrazone (FCCP). The Deltapsi(m) was higher (P

Differential expression of mitochondrial and extramitochondrial proteins in lymphocytes of male broilers with low and high feed efficiency.

Studies were conducted to investigate relationships between mitochondrial and extramitochondrial protein expression, and protein oxidation in lymphocytes obtained from broilers in which individual feed efficiencies were obtained. Lymphocytes were isolated from male broilers from a single line that were shown to exhibit either low (0.48 +/- 0.02, n = 8) or high (0.68 +/- 0.01, n = 7) feed efficiency (FE). Western blot analysis showed that, compared with lymphocytes from high FE broilers, lymphocytes from low FE broilers exhibited a) higher amounts of oxidized proteins (protein carbonyls), b) lower amounts of 3 mitochondrial proteins [core I, cyt c 1 (complex III), and ATP synthase (complex V)], and c) higher amounts of 2 proteins [30 S (complex II) and COX II (complex IV)]. Two-dimensional gel electrophoresis revealed that the intensities of 25 protein spots from pooled samples of lymphocytes from high and low FE broilers differed by 5-fold or more. Three of these protein spots were picked from the gel and subjected to matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry analysis. One protein spot of ~33 kDa was tentatively identified by MALDI-TOF as a fragment of collapsin-2, a component of semaphorin 3D. The results of this study provide further evidence of increased oxidation associated with low FE and further evidence of differential protein expression associated with the phenotypic expression of feed efficiency.