The nuclear lamins function in the regulation of replication, transcription, and epigenetic modifications of chromatin. However, the mechanisms responsible for these lamin functions are poorly understood. We demonstrate that A-and B-type lamins form separate, but interacting, stable meshworks in the lamina and have different mobilities in the nucleoplasm as determined by fluorescence correlation spectroscopy (FCS). [Keywords: Lamins; chromatin; RNA polymerase II transcription; chromosome organization] Supplemental material is available at http://www.genesdev.org. Silencing lamin B1 (LB1) expression dramatically increases the lamina meshwork size and the mobility of nucleoplasmic lamin A (LA). The changes in lamina mesh

Proteins with expanded polyQ repeats are associated with at least nine neurodegenerative disorders including ataxins 1 and 3, Kennedy's disease, and Huntington's disease (HD) 1,2 . These diseases are dominantly inherited and although the polyQ-containing proteins are expressed widely in the brain, they result in selective neuronal death. There is a significant and striking correlation between the length of the polyQ repeat and pathology; longer repeats result in earlier onset and more severe symptoms with the threshold of approximately 40 glutamine residues. In the case of HD, for example, expanded polyQ in huntingtin (htt) protein causes disease 3,4 . A characteristic of the polyQ diseases is the appearance of neuronal inclusions that are formed by aggregation of the polyQ proteins with other cellular proteins 5,6 . This has led to the "toxic gain-of-function" hypothesis that essential proteins can be sequestered, which 3 over time leads to cellular dysgenesis. The expression of polyQ can cause other metastable proteins to lose functionality, and in turn these proteins amplify the toxicity of polyQ by enhancing overall aggregation 7 . Self-aggregation of polyQ proteins has been proposed to be mediated by association of parallel β-sheet structures 8 . However, the intrinsic in vivo events leading to the aggregation of polyQ proteins remain poorly understood.Protein misfolding is a natural consequence of protein biogenesis. To combat cytotoxicity that results from the accumulation of misfolded proteins, all cells express molecular chaperones that are essential for the productive folding of proteins 9,10 . Molecular chaperones are of several classes; for example, Hsp70/J-domain proteins interact with unfolded or partially folded proteins in concert with co-chaperones, while the chaperone machines of the chaperonin (Hsp60) family form cage-like structures that sequester non-native states of proteins 11 . The chaperonin containing t-complex polypeptide 1 (CCT)/t-complex polypeptide 1 ring complex (TRiC) is a member of chaperonin family 12 that facilitates the folding of proteins in the eukaryotic cytosol upon ATP hydrolysis 13,14 . CCT shows a weak but significant homology to E. coli GroEL and forms a hexadecamer double-troidal complex composed of eight different subunits 15,16 . Substrate proteins are captured in the cavity, and released after folding is completed 17 . Approximately 10% of newly-synthesized proteins have been proposed to be recognized by CCT.Recently, in a genome-wide screen to identify modifier genes for polyQ aggregation in C. elegans, approximately 200 genes were found to be required for the prevention of polyQ aggregation 18 . This included the genes encoding two Hsp70s, one J-protein, and six CCT subunits. These observations suggested a 4 role of CCT in preventing polyQ aggregation. We show here in mammalian cells that CCT has a key protective role against the toxicity of htt/polyQ and affects aggregation process at the soluble stage. In the context of our recent in vitro data showing that ...

Programmed cell death protein-1/programmed cell death ligand-1 (PD-1/PD-L1) pathway blockade is a promising new cancer therapy. Although PD-1/PD-L1 treatment has yielded clinical benefits in several types of cancer, further studies are required to clarify predictive biomarkers for drug efficacy and to understand the fundamental mechanism of PD-1/PD-L1 interaction between host and tumor cells. Here, we show that exosomes derived from lung cancer cells express PD-L1 and play a role in immune escape by reducing T-cell activity and promoting tumor growth. The abundance of PD-L1 on exosomes represented the quantity of PD-L1 expression on cell surfaces. Exosomes containing PD-L1 inhibited interferon-gamma (IFN-γ) secretion by Jurkat T cells. IFN-γ secretion was restored by PD-L1 knockout or masking on the exosomes. Both forced expression of PD-L1 on cells without PD-L1 and treatment with exosomes containing PD-L1 enhanced tumor growth in vivo. PD-L1 was present on exosomes isolated from the plasma of patients with non-small cell lung cancer, and its abundance in exosomes was correlated with PD-L1 positivity in tumor tissues. Exosomes can impair immune functions by reducing cytokine production and inducing apoptosis in CD8+ T cells. Our findings indicate that tumor-derived exosomes expressing PD-L1 may be an important mediator of tumor immune escape.

BSTRACTNuclear lamins form the major structural elements that comprise the nuclear lamina. Loss of nuclear structural integrity has been implicated as a key factor in the lamin A/C gene mutations that cause laminopathies, whereas the normal regulation of lamin A assembly and organization in interphase cells is still undefined. We assumed phosphorylation to be a major determinant, identifying 20 prime interphase phosphorylation sites, of which eight were highturnover sites. We examined the roles of these latter sites by sitedirected mutagenesis, followed by detailed microscopic analysisincluding fluorescence recovery after photobleaching, fluorescence correlation spectroscopy and nuclear extraction techniques. The results reveal three phosphorylation regions, each with dominant sites, together controlling lamin A structure and dynamics. Interestingly, two of these interphase sites are hyper-phosphorylated in mitotic cells and one of these sites is within the sequence that is missing in progerin of the Hutchinson-Gilford progeria syndrome. We present a model where different phosphorylation combinations yield markedly different effects on the assembly, subunit turnover and the mobility of lamin A between, and within, the lamina, the nucleoplasm and the cytoplasm of interphase cells.

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Tumor cells shed an abundance of extracellular vesicles (EVs) to body fluids containing bioactive molecules including DNA, RNA, and protein. Investigations in the field of tumor-derived EVs open a new horizon in understanding cancer biology and its potential as cancer biomarkers as well as platforms for personalized medicine. This study demonstrates that successfully isolated EVs from plasma and bronchoalveolar lavage fluid (BALF) of non-small cell lung cancer (NSCLC) patients contain DNA that can be used for EGFR genotyping through liquid biopsy. In both plasma and BALF samples, liquid biopsy results using EV DNA show higher accordance with conventional tissue biopsy compared to the liquid biopsy of cfDNA. Especially, liquid biopsy with BALF EV DNA is tissue-specific and extremely sensitive compared to using cfDNA. Furthermore, use of BALF EV DNA also demonstrates higher efficiency in comparison to tissue rebiopsy for detecting p.T790 M mutation in the patients who developed resistance to EGFR-TKIs. These finding demonstrate possibility of liquid biopsy using EV DNA potentially replacing the current diagnostic methods for more accurate, cheaper, and faster results.Electronic supplementary materialThe online version of this article (10.1186/s12943-018-0772-6) contains supplementary material, which is available to authorized users.

Nanoparticles have been extensively used to deliver therapeutic drugs to tumor tissues through the extravasation of a leaky vessel via enhanced permeation and retention effect (EPR, passive targeting) or targeted interaction of tumor-specific ligands (active targeting). However, the therapeutic efficacy of drug-loaded nanoparticles is hampered by its heterogeneous distribution owing to limited penetration in tumor tissue. Inspired by the fact that cancer cells can recruit inflammatory immune cells to support their survival, we developed a click reactionassisted immune cell targeting (CRAIT) strategy to deliver drug-loaded nanoparticles deep into the avascular regions of the tumor. Immune cell-targeting CD11b antibodies are modified with trans-cyclooctene to enable bioorthogonal click chemistry with mesoporous silica nanoparticles functionalized with tetrazines (MSNs-Tz). Sequential injection of modified antibodies and MSNs-Tz at intervals of 24 h results in targeted conjugation of the nanoparticles onto CD11b + myeloid cells, which serve as active vectors into tumor interiors. We show that the CRAIT strategy allows the deep tumor penetration of drug-loaded nanoparticles, resulting in enhanced therapeutic efficacy in an orthotopic 4T1 breast tumor model. The CRAIT strategy does not require ex vivo manipulation of cells and can be applied to various types of cells and nanovehicles.

The principle factors underlying gastric cancer (GC) development and outcomes are not well characterized resulting in a paucity of validated therapeutic targets. To identify potential molecular targets, we analyze gene expression data from GC patients and identify the nuclear receptor ESRRG as a candidate tumor suppressor. ESRRG expression is decreased in GC and is a predictor of a poor clinical outcome. Importantly, ESRRG suppresses GC cell growth and tumorigenesis. Gene expression profiling suggests that ESRRG antagonizes Wnt signaling via the suppression of TCF4/LEF1 binding to the CCND1 promoter. Indeed, ESRRG levels are found to be inversely correlated with Wnt signaling-associated genes in GC patients. Strikingly, the ESRRG agonist DY131 suppresses cancer growth and represses the expression of Wnt signaling genes. Our present findings thus demonstrate that ESRRG functions as a negative regulator of the Wnt signaling pathway in GC and is a potential therapeutic target for this cancer.