The influenza virus (IFV) acquires its envelope by budding from host cell plasma membranes. Using quantitative shotgun mass spectrometry, we determined the lipidomes of the host Madin-Darby canine ...kidney cell, its apical membrane, and the IFV budding from it. We found the apical membrane to be enriched in sphingolipids (SPs) and cholesterol, whereas glycerophospholipids were reduced, and storage lipids were depleted compared with the whole-cell membranes. The virus membrane exhibited a further enrichment of SPs and cholesterol compared with the donor membrane at the expense of phosphatidylcholines. Our data are consistent with and extend existing models of membrane raft-based biogenesis of the apical membrane and IFV envelope.
Biglycan (BGN), a proteoglycan of the extracellular matrix, is included in mRNA signatures for prostate cancer aggressiveness. To understand the impact of BGN on prognosis and its relationship to ...molecularly defined subsets, we analyzed BGN expression by immunohistochemistry on a tissue microarray containing 12,427 prostate cancers. Seventy-eight percent of 11,050 interpretable cancers showed BGN expression, which was considered as low intensity in 47.7% and as high intensity in 31.1% of cancers. BGN protein expression rose with increasing pathological tumor stage, Gleason grade, lymph node metastasis and early PSA recurrence (P<.0001 each). Comparison with our molecular database attached to the TMA revealed that BGN expression was linked to presence of TMPRRS2:ERG fusion and PTEN deletion (P<.0001 each). In addition, BGN was strongly linked to androgen-receptor (AR) levels (P<.0001), suggesting a hormone-depending regulation of BGN. BGN up-regulation is a frequent feature of prostate cancer that parallels tumor progression and may be useful to estimate tumor aggressiveness particularly if combined with other molecular markers.
Microtubule-associated protein Tau (MAPT) overexpression has been linked to poor prognosis and decreased response to taxane-based therapies in several cancer types, but its relevance in prostate ...cancer is unknown.
In this study, MAPT expression was analyzed by immunohistochemistry on a tissue microarray containing 17,747 prostate cancers.
MAPT was absent in normal prostate epithelial cells but detectable in 1004 (8.2%) of 12,313 interpretable cancers. Its expression was associated with advanced tumor stage, high Gleason grade, positive lymph nodes, and early biochemical recurrence (p < 0.0001 each). For example, MAPT was found in 3.6% of 2072 Gleason ≤3 + 3 cancers but in 14.4% of 704 Gleason ≥4 + 4 cancers. High-level MAPT staining was also linked to TMPRSS2:ERG fusions (p < 0.0001). MAPT staining was seen in 15.2 and 16% of cancers with TMPRSS2:ERG fusion detected by immunohistochemistry and fluorescence in-situ hybridization, but in only 3.5 and 3.9% of cancers without ERG staining or ERG rearrangements. Moreover, an association was found between MAPT expression and PTEN deletions, with 19% MAPT positivity in 948 PTEN deleted cancers but only 7% MAPT positivity in 3895 tumors with normal PTEN copy numbers (p < 0.0001). Multivariate analysis revealed that the prognostic value of MAPT was independent from established parameters. Conventional large section analyses showed intratumoral MAPT heterogeneity in all three analyzed cancers.
The results of our study identify MAPT, as a moderate prognostic marker in prostate cancer, whose clinical impact, however, may be limited due to the rarity and heterogeneity of its expression.
Background
Enhancer of zeste homolog 2 (EZH2), the catalytic subunit of the polycomb repressive complex 2, plays an important role in tumor development and progression by interacting with histone and ...non‐histone proteins. EZH2 represents a putative therapeutic target and has been suggested as a prognostic marker in several cancer types.
Material and Methods
This study investigates the prognostic relevance of immunohistochemical EZH2 expression in head and neck squamous cell carcinoma. Tissue microarray sections with 667 cancers of oral cavity, oro‐ and hypopharynx and larynx were analyzed for EZH2 expression.
Results
Nuclear EZH2 staining was recorded in 322 (81.8%) of 394 cases. Staining was weak in 33 (10.2%), moderate in 128 (39.6%), and strong in 103 (32.0%) cancers. The prevalence of EZH2 expression in tumors of the oral cavity and the orohypopharynx was higher as compared to cancers of the larynx (P = .0023). EZH2 expression was correlated to presence of lymph node metastasis (P = .0089) but was unrelated to histological grade, tumor stage, surgical margin, or distant metastasis. EZH2 expression had no impact on patient survival.
Conclusion
The high prevalence of EZH2 expression in head and neck squamous cell carcinoma stresses its capability as a therapeutic target.
Prostate Stem Cell Antigen (PSCA) is frequently expressed in prostate cancer but its exact function is unclear.
To clarify contradictory findings on the prognostic role of PSCA expression, a tissue ...microarray containing 13,665 prostate cancers was analyzed by immunohistochemistry.
PSCA staining was absent in normal epithelial and stromal cells of the prostate. Membranous and cytoplasmic PSCA staining was seen in 53.7% of 9642 interpretable tumors. Staining was weak in 22.4%, moderate in 24.5% and strong in 6.8% of tumors. PSCA expression was associated with favorable pathological and clinical tumor features: Early pathological tumor stage (p < 0.0001), low Gleason grade (p < 0.0001), absence of lymph node metastasis (p < 0.0001), low pre-operative PSA level (p = 0.0118), negative surgical margin (p < 0.0001) and reduced PSA recurrence (p < 0.0001). PSCA expression was an independent predictor of prognosis in multivariate analysis (hazard ratio 0.84, p < 0.0001).
The absence of statistical relationship to TMPRSS2:ERG fusion status, chromosomal deletion or high tumor cell proliferation argues against a major role of PSCA for regulation of cell cycle or genomic integrity. PSCA expression is linked to favorable prognosis. PSCA measurement is a candidate for inclusion in multi-parametric prognostic prostate cancer tests.
FOXA1 (Fork-head box protein A1, HNF-3a) is a transcription factor involved in androgen signaling with relevance for lineage-specific gene expression of the prostate. The expression was analyzed by ...immunohistochemistry on a tissue microarray containing 11152 prostate cancer specimens. Results were compared with tumor phenotype, biochemical recurrence, androgen receptor expression, ETS-related gene (ERG) status and other recurrent genomic alterations. FOXA1 expression was detectable in 97.6% of 8227 interpretable cancers and considered strong in 28.5%, moderate in 46.2% and weak in 22.9% of cases. High FOXA1 expression was associated with TMPRSS2:ERG rearrangement and ERG expression (P < 0.0001). High FOXA1 expression was linked to high Gleason grade, advanced pathological tumor (pT) stage and early PSA recurrence in ERG negative cancers (P < 0.0001), while these associations were either weak or absent in ERG positive cancers. In ERG negative cancers, the prognostic role of FOXA1 expression was independent of Gleason grade, pathological tumor stage, lymph node stage, surgical margin status and preoperative PSA. Independent prognostic value became even more evident if the analysis was limited to preoperatively available features such as biopsy Gleason grade, preoperative PSA, cT stage and FOXA1 expression (P < 0.0001). Within ERG negative cancers, FOXA1 expression was also strongly associated with PTEN and 5q21 deletions (P < 0.0001). High expression of FOXA1 is an independent prognostic parameter in ERG negative prostate cancer. Thus, FOXA1 measurement might provide clinically useful information in prostate cancer.
The chromatin‐organizing factor CCCTC‐binding factor (CTCF) is involved in transcriptional regulation, DNA‐loop formation, and telomere maintenance. To evaluate the clinical impact of CTCF in ...prostate cancer, we analyzed CTCF expression by immunohistochemistry on a tissue microarray containing 17 747 prostate cancers. Normal prostate tissue showed negative to low CTCF expression, while in prostate cancers, CTCF expression was seen in 7726 of our 12 555 (61.5%) tumors and was considered low in 44.6% and high in 17% of cancers. Particularly, high CTCF expression was significantly associated with the presence of the transmembrane protease, serine 2:ETS‐related gene fusion: Only 10% of ERG‐negative cancers, but 30% of ERG‐positive cancers had high‐level CTCF expression (P < 0.0001). CTCF expression was significantly associated with advanced pathological tumor stage, high Gleason grade (P < 0.0001 each), nodal metastasis (P = 0.0122), and early biochemical recurrence (P < 0.0001). Multivariable modeling revealed that the prognostic impact of CTCF was independent from established presurgical parameters such as clinical stage and Gleason grade of the biopsy. Comparison with key molecular alterations showed strong associations with the expression of the Ki‐67 proliferation marker and presence of phosphatase and tensin homolog deletions (P < 0.0001 each). The results of our study identify CTCF expression as a candidate biomarker for prognosis assessment in prostate cancer.
The transcriptional repressor CCCTC‐binding factor, which is involved in modeling the chromatin face in the nucleus of a cell, was analyzed for its expression in prostate cancer. We report here that its upregulation was associated with a shorter prostate‐specific antigen recurrence‐free survival after prostatectomy in a large cohort of prostate cancer patients.
The current risk stratification in prostate cancer (PCa) is frequently insufficient to adequately predict disease development and outcome. One hallmark of cancer is telomere maintenance. For telomere ...maintenance, PCa cells exclusively employ telomerase, making it essential for this cancer entity. However, TERT, the catalytic protein component of the reverse transcriptase telomerase, itself does not suit as a prognostic marker for prostate cancer as it is rather low expressed. We investigated if, instead of
, transcription factors regulating
may suit as prognostic markers. To identify transcription factors regulating
, we developed and applied a new gene regulatory modeling strategy to a comprehensive transcriptome dataset of 445 primary PCa. Six transcription factors were predicted as
regulators, and most prominently, the developmental morphogenic factor PITX1. PITX1 expression positively correlated with telomere staining intensity in PCa tumor samples. Functional assays and chromatin immune-precipitation showed that PITX1 activates
expression in PCa cells. Clinically, we observed that PITX1 is an excellent prognostic marker, as concluded from an analysis of more than 15,000 PCa samples. PITX1 expression in tumor samples associated with (i) increased Ki67 expression indicating increased tumor growth, (ii) a worse prognosis, and (iii) correlated with telomere length.
TFAP2D is a transcription factor important for modulating gene expression in embryogenesis. Its expression and prognostic role in prostate cancer has not been evaluated.
Therefore, a tissue ...microarray containing 17,747 prostate cancer specimens with associated pathological, clinical, and molecular data was analyzed by immunohistochemistry to assess the role of TFAP2D.
TFAP2D expression was typically increased in prostate cancer as compared to adjacent non-neoplastic glands. TFAP2D staining was considered negative in 24.3% and positive in 75.7% of 13,545 interpretable cancers. TFAP2D staining was significantly linked to advanced tumor stage, high classical and quantitative Gleason grade, lymph node metastasis, and a positive surgical margin (p ≤ 0.0045). TFAP2D positivity was more common in ERG fusion positive (88.7%) than in ERG negative cancers (66.8%; p < 0.0001). Subset analyses in 3776 cancers with and 4722 cancers without TMPRSS2:ERG fusion revealed that associations with tumor phenotype and patient outcome were largely driven by the subset of ERG negative tumors. Multivariate analysis did not identify TFAP2D protein expression levels as a robust independent prognostic parameter. Positive TFAP2D immunostaining was significantly associated with 10 of 11 previously analyzed chromosomal deletions in ERG negative cancers (p ≤ 0.0244 each) indicating that elevated TFAP2D expression parallels genomic instability in prostate cancer.
These data demonstrate that TFAP2D protein overexpression is linked to prostate cancer progression and genomic instability in ERG negative prostate cancers.
The envelope of Human Immunodeficiency Virus type 1 (HIV-1) consists of a liquid-ordered membrane enriched in raft lipids and containing the viral glycoproteins. Previous studies demonstrated that ...changes in viral membrane lipid composition affecting membrane structure or curvature can impair infectivity. Here, we describe novel antiviral compounds that were identified by screening compound libraries based on raft lipid-like scaffolds. Three distinct molecular structures were chosen for mode-of-action studies, a sterol derivative (J391B), a sphingosine derivative (J582C) and a long aliphatic chain derivative (IBS70). All three target the viral membrane and inhibit virus infectivity at the stage of fusion without perturbing virus stability or affecting virion-associated envelope glycoproteins. Their effect did not depend on the expressed envelope glycoproteins or a specific entry route, being equally strong in HIV pseudotypes carrying VSV-G or MLV-Env glycoproteins. Labeling with laurdan, a reporter of membrane order, revealed different membrane structure alterations upon compound treatment of HIV-1, which correlated with loss of infectivity. J582C and IBS70 decreased membrane order in distinctive ways, whereas J391B increased membrane order. The compounds' effects on membrane order were reproduced in liposomes generated from extracted HIV lipids and thus independent both of virion proteins and of membrane leaflet asymmetry. Remarkably, increase of membrane order by J391B required phosphatidylserine, a lipid enriched in the HIV envelope. Counterintuitively, mixtures of two compounds with opposite effects on membrane order, J582C and J391B, did not neutralize each other but synergistically inhibited HIV infection. Thus, altering membrane order, which can occur by different mechanisms, constitutes a novel antiviral mode of action that may be of general relevance for enveloped viruses and difficult to overcome by resistance development.
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