Experimental Verification of Dissipation-Time Uncertainty Relation.

Dissipation is vital to any cyclic process in realistic systems. Recent research focus on nonequilibrium processes in stochastic systems has revealed a fundamental trade-off, called dissipation-time uncertainty relation, that entropy production rate associated with dissipation bounds the evolution pace of physical processes [Phys. Rev. Lett. 125, 120604 (2020)PRLTAO0031-900710.1103/PhysRevLett.125.120604]. Following the dissipative two-level model exemplified in the same Letter, we experimentally verify this fundamental trade-off in a single trapped ultracold ^{40}Ca^{+} ion using elaborately designed dissipative channels, along with a postprocessing method developed in the data analysis, to build the effective nonequilibrium stochastic evolutions for the energy transfer between two heat baths mediated by a qubit. Since the dissipation-time uncertainty relation imposes a constraint on the quantum speed regarding entropy flux, our observation provides the first experimental evidence confirming such a speed restriction from thermodynamics on quantum operations due to dissipation, which helps us further understand the role of thermodynamical characteristics played in quantum information processing.

ERK-dependent IL-6 autocrine signaling mediates adaptive resistance to pan-PI3K inhibitor BKM120 in head and neck squamous cell carcinoma.

Hyperactivation of phosphatidylinositol 3-kinase (PI3K) pathway occurs frequently in head and neck squamous cell carcinoma (HNSCC). However, clinical outcomes of targeting the PI3K pathway have been underwhelming. In present study, we investigated the resistant mechanisms and potential combination therapeutic strategy to overcome adaptive resistance to PI3K inhibitor in HNSCC. Treatment of NVP-BKM120, a pan-PI3K inhibitor, led to upregulation of interleukin-6 (IL-6) and subsequent activation of either extracellular signal-regulated kinase (ERK) or signal transducers and activators of transcription 3 (STAT3), causing modest antitumor effects on the growth of HNSCC cells. Blockade of autocrine IL-6 signaling with siRNA or neutralizing antibody for IL-6 receptor (IL-6R) completely abolished NVP-BKM120-induced activation of ERK and STAT3 as well as expression of c-Myc oncogene, which resulted in enhanced sensitivity to NVP-BKM120. Moreover, when compared with a pharmacologic inhibitor or silencing of STAT3, trametinib, a MEK inhibitor, in combination with NVP-BKM120 yielded more potent anti-proliferative effects by inhibiting S phase transition, arresting cells at G0/G1 phase, and downregulating IL-6 and c-Myc expression. Furthermore, as compared with either agent alone, combination of NVP-BKM120 with trametinib or tocilizumab, a humanized anti-IL-6R antibody, significantly suppressed tumor growth in NVP-BKM120-resistant patient-derived tumor xenograft (PDTX) models, which was also confirmed in PDTX-derived cell lines. Collectively, these results suggested that IL-6/ERK signaling is closely involved in adaptive resistance of NVP-BKM120 in HNSCC cells, providing a rationale for a novel combination therapy to overcome resistance to PI3K inhibitors.

Effects of lobeglitazone, a novel thiazolidinedione, on adipose tissue remodeling and brown and beige adipose tissue development in db/db mice.

BACKGROUND/OBJECTIVES: We investigated the effect of long-term treatment with lobeglitazone, a novel thiazolidinedione-based activator of peroxisome proliferator-activated receptor gamma, on adipose tissue (AT), focusing on its effects on insulin resistance in obese db/db mice. METHODS: Seven-week-old male db/db mice were assigned to either a vehicle-treated (n=8) or lobeglitazone-treated (n=8) group. Lobeglitazone (1 mg kg-1 daily) was injected intraperitoneally for 20 weeks. RESULTS: Lobeglitazone treatment for 20 weeks resulted in a remarkably improved glycemic index, including significantly decreased glucose levels, enhanced insulin sensitivity and preserved pancreatic beta cells. Both whole body and subcutaneous AT weight increased in the lobeglitazone-treated group. However, lobeglitazone induced an increase in the number of small adipocyte in both epididymal and subcutaneous AT, with a significant weight decrease in the epididymal AT of db/db mice. Using flow cytometry, the CD11c-positive M1 macrophages and CD206-positive M2 macrophages in the epididymal AT were observed to exhibit a decreased M1-to-M2 ratio in lobeglitazone-treated db/db mice. Furthermore, in the lobeglitazone-treated group, interscapular brown AT was clearly visualized by 18F-fluoro-2-deoxy-D-glucose positron emission tomography combined with computed tomography (18F-FDG-PET/CT) and its mass was significantly greater than that of the vehicle-treated group. In the lobeglitazone-treated group, beige-specific gene expression and the number of mitochondria in white AT were upregulated. Lobeglitazone, with upregulating interferon regulatory factor-4 (a key transcriptional regulator of thermogenesis), promoted the development of brown adipocytes and the differentiation of white adipocytes into beige adipocytes. CONCLUSIONS: Long-term lobeglitazone treatment has a beneficial role in remodeling and ameliorating inflammation in white AT and in glycemic control, in relation to insulin sensitivity in obese db/db mice. Moreover, lobeglitazone induced the differentiation of brown and beige adipocytes. Collectively, our data suggest that lobeglitazone treatment provides promising effects on white and brown AT as well as great improvement in glycemic control, as a potent insulin sensitizer.

Co-clinical trials demonstrate predictive biomarkers for dovitinib, an FGFR inhibitor, in lung squamous cell carcinoma.

BACKGROUND: We conducted co-clinical trials in patient-derived xenograft (PDX) models to identify predictive biomarkers for the multikinase inhibitor dovitinib in lung squamous cell carcinoma (LSCC). METHODS: The PDX01-02 were established from LSCC patients enrolled in the phase II trial of dovitinib (NCT01861197) and PDX03-05 were established from LSCC patients receiving surgery. These five PDX tumors were subjected to in vivo test of dovitinib efficacy, whole exome sequencing and gene expression profiling. RESULTS: The PDX tumors recapitulate histopathological properties and maintain genomic characteristics of originating tumors. Concordant with clinical outcomes of the trial enrolled-LSCC patients, dovitinib produced substantial tumor regression in PDX-01 and PDX-05, whereas it resulted in tumor progression in PDX-02. PDX-03 and -04 also displayed poor antitumor efficacy to dovitinib. Mutational and genome-wide copy number profiles revealed no correlation between genomic alterations of FGFR1-3 and sensitivity to dovitinib. Of note, gene expression profiles revealed differentially expressed genes including FGF3 and FGF19 between PDX-01 and 05 and PDX-02-04. Pathway analysis identified two FGFR signaling-related gene sets, FGFR ligand binding/activation and SHC-mediated cascade pathway were substantially up-regulated in PDX-01 and 05, compared with PDX-02-04. The comparison of gene expression profiles between dovitinib-sensitive versus -resistant lung cancer cell lines in the Cancer Cell Line Encyclopedia database also found that transcriptional activation of 18 key signaling components in FGFR pathways can predict the sensitivity to dovitinib both in cell lines and PDX tumors. These results highlight FGFR pathway activation as a key molecular determinant for sensitivity to dovitinib. CONCLUSIONS: FGFR gene expression signatures are predictors for the response to dovitinib in LSCC.

Oncogenic BRAF fusions in mucosal melanomas activate the MAPK pathway and are sensitive to MEK/PI3K inhibition or MEK/CDK4/6 inhibition.

Despite remarkable progress in cutaneous melanoma genomic profiling, the mutational landscape of primary mucosal melanomas (PMM) remains unclear. Forty-six PMMs underwent targeted exome sequencing of 111 cancer-associated genes. Seventy-six somatic nonsynonymous mutations in 42 genes were observed, and recurrent mutations were noted on eight genes, including TP53 (13%), NRAS (13%), SNX31 (9%), NF1 (9%), KIT (7%) and APC (7%). Mitogen-activated protein kinase (MAPK; 37%), cell cycle (20%) and phosphatidylinositol 3-kinase (PI3K)-mTOR (15%) pathways were frequently mutated. We biologically characterized a novel ZNF767-BRAF fusion found in a vemurafenib-refractory respiratory tract PMM, from which cell line harboring ZNF767-BRAF fusion were established for further molecular analyses. In an independent data set, NFIC-BRAF fusion was identified in an oral PMM case and TMEM178B-BRAF fusion and DGKI-BRAF fusion were identified in two malignant melanomas with a low mutational burden (number of mutation per megabase, 0.8 and 4, respectively). Subsequent analyses revealed that the ZNF767-BRAF fusion protein promotes RAF dimerization and activation of the MAPK pathway. We next tested the in vitro and in vivo efficacy of vemurafenib, trametinib, BKM120 or LEE011 alone and in combination. Trametinib effectively inhibited tumor cell growth in vitro, but the combination of trametinib and BKM120 or LEE011 yielded more than additive anti-tumor effects both in vitro and in vivo in a melanoma cells harboring the BRAF fusion. In conclusion, BRAF fusions define a new molecular subset of PMM that can be targeted therapeutically by the combination of a MEK inhibitor with PI3K or cyclin-dependent kinase 4/6 inhibitors.

Activation of the Met kinase confers acquired drug resistance in FGFR-targeted lung cancer therapy.

Aberrant fibroblast growth factor receptor (FGFR) activation/expression is a common feature in lung cancer (LC). In this study, we evaluated the antitumor activity of and the mechanisms underlying acquired resistance to two potent selective FGFR inhibitors, AZD4547 and BAY116387, in LC cell lines. The antitumor activity of AZD4547 and BAY1163877 was screened in 24 LC cell lines, including 5 with FGFR1 amplification. Two cell lines containing FGFR1 amplifications, H1581 and DMS114, were sensitive to FGFR inhibitors (IC50<250 nm). Clones of FGFR1-amplified H1581 cells resistant to AZD4547 or BAY116387 (H1581AR and H1581BR cells, respectively) were established. Receptor tyrosine kinase (RTK) array and immunoblotting analyses showed strong overexpression and activation of Met in H1581AR/BR cells, compared with that in the parental cells. Gene set enrichment analysis against the Kyoto Encyclopedia of Genes and Genomes (KEGG) database showed that cytokine-cytokine receptor interaction pathways were significantly enriched in H1581AR/BR cells, with Met contributing significantly to the core enrichment. Genomic DNA quantitative PCR and fluorescent in situ hybridization analyses showed MET amplification in H1581AR, but not in H1581BR, cells. Met amplification drives acquired resistance to AZD4547 in H1581AR cells by activating ErbB3. Combination treatment with FGFR inhibitors and an anaplastic lymphoma kinase (ALK)/Met inhibitor, crizotinib, or Met-specific short interfering RNA (siRNA) synergistically inhibited cell proliferation in both H1581AR and H1581BR cells. Conversely, ectopic expression of Met in H1581 cells conferred resistance to AZD4547 and BAY1163877. Acquired resistance to FGFR inhibitors not only altered cellular morphology, but also promoted migration and invasion of resistant clones, in part by inducing epithelial-to-mesenchymal transition. Taken together, our data suggest that Met activation is sufficient to bypass dependency on FGFR signaling. Concurrent inhibition of the Met and FGFR pathways may have synergistic clinical benefits when targeting FGFR-dependent LC.

Exogenous administration of DLK1 ameliorates hepatic steatosis and regulates gluconeogenesis via activation of AMPK.

BACKGROUND/OBJECTIVES: Activation of Notch signaling pathologically enhances lipogenesis and gluconeogenesis in the liver causing non-alcoholic fatty liver disease (NAFLD) and diabetes. Delta-like 1 homolog (DLK1), an imprinted gene that can modulate adipogenesis and muscle development in mice, was found as an inhibitory regulator of Notch signaling. Therefore, we investigated the metabolic effect of exogenous DLK1 in vitro and in vivo. SUBJECTS/METHODS: A soluble DLK1 peptide was generated with fusion between a human Fc fragment and extracellular domain of DLK1. Male db/db mice were randomly assigned to two groups: vehicle treated and DLK1-treated group (25 mg kg(-1), intraperitoneal injection, twice a week for 4 weeks). Primary mice hepatocytes and HepG2 cells were used for in vitro experiments. RESULTS: After 4 weeks of DLK1 administration, hepatic triglyceride content and lipid droplets in liver tissues, as well as serum levels of liver enzymes, were markedly decreased in db/db mice. DLK1 treatment induced phosphorylation of AMPK and ACC and suppressed nuclear expression of SREBP-1c in the mouse liver or hepatocytes, indicating regulation of fatty acid oxidation and synthesis pathways. Furthermore, DLK1-treated mice showed significantly lower levels of fasting and random glucose, with improved glucose and insulin tolerance compared with the vehicle-treated group. Macrophage infiltration and proinflammatory cytokine levels in the epididymal fat were decreased in DLK1-treated db/db mice. Moreover, DLK1 suppressed glucose production from hepatocytes, which was blocked after co-administration of an AMPK inhibitor, compound C. DLK1-treated hepatocytes and mouse liver tissues showed lower PEPCK and G6Pase expression. DLK1 triggered AKT phosphorylation followed by cytosolic translocation of FOXO1 from the nucleus in hepatocytes. CONCLUSIONS: The present study demonstrated that exogenous administration of DLK1 reduced hepatic steatosis and hyperglycemia via AMPK activation in the liver. This result suggests that DLK1 may be a novel therapeutic approach for treating NAFLD and diabetes.