N-Acenoacenes: Synthesis and Solid-State Properties.

Four N-acenoacenes were synthesized and analyzed for their optoelectronic properties and solid-state packings. Two of the regioisomeric acridinoacridines are TIPS-ethynylated, whereas the other pair are Boc- and triflate substituted derivatives. The two TIPS-ethynyldiazaacenoacenes were processed into organic thin-film transistors with saturation hole mobilities reaching 2.9×10-2  cm2 (Vs)-1 .

The Radical Anion, Dianion and Electron Transport Properties of Tetraiodotetraazapentacene.

Tetraiodotetraazapentacene I4 TAP, the last missing derivative in the series of halogenated silylated tetraazapentacenes, was synthesized via condensation chemistry from a TIPS-ethynylated diaminobenzothiadiazol in three steps. Single and double reduction furnished its air-stable monoanion and relatively air-stable dianion, both of which were characterized by crystallography. All three species are structurally and spectroscopically compared to non-halogenated TAP and Br4 TAP. I4 TAP is an n-channel material in thin-film transistors with average electron mobilities exceeding 1 cm2 (Vs)-1 .

Nested Sampling aided determination of tantalum optical constants in the EUV spectral range.

We report on determining the optical constants of Ta in the sub-extreme ultraviolet (EUV) spectral range 5.0-24.0 nm from the angle-dependent reflectance (ADR) measured using monochromatized synchrotron radiation. Two sputtered samples with differing thicknesses were investigated. Complementarily x-ray reflectance was measured at shorter wavelengths and evaluated by Fourier transform to facilitate an unambiguous selection of a model for the data evaluation based on an inverse solution of the Fresnel's equations for a layered system. Bayesian inferences coupled with a Nested Sampling (NS) algorithm were utilized to derive the optical constants with their corresponding uncertainties. This report further emphasizes the applicability of an acclaimed NS algorithm on a high-dimensional inverse problem. We explore the possibility of addressing the correlations between the optical constants of thin films and their structural parameters based on other established studies.

Diazapentacenes from Quinacridones.

Bis(silylethynylated) 5,7- and 5,12-diazapentacenes were synthesized from cis- and trans-quinacridone using protection, alkynylation and deoxygenation. The solid-state packing of the targets is determined by choice and position of the silylethynyl substituents. The position of the substituents and nitrogen atoms influence the optical properties of the targets.

Stable N,N'-Diarylated Dihydrodiazaacene Radical Cations.

Three stable N,N'-diarylated dihydroazaacene radical cations were prepared by oxidation of neutral N,N'-diarylated dihydroazaacenes synthesized via palladium-catalyzed Buchwald-Hartwig aminations of aryl iodides with N,N'-dihydroazaacenes. Both neutral as well as oxidized species were investigated via UV-vis spectroscopy, single crystal analysis, and DFT calculations. All the radical cations are surprisingly stable-their absorption spectra in dichloromethane remain unchanged in ambient conditions for at least 24 hours.

Therapy-induced tumour secretomes promote resistance and tumour progression.

Drug resistance invariably limits the clinical efficacy of targeted therapy with kinase inhibitors against cancer. Here we show that targeted therapy with BRAF, ALK or EGFR kinase inhibitors induces a complex network of secreted signals in drug-stressed human and mouse melanoma and human lung adenocarcinoma cells. This therapy-induced secretome stimulates the outgrowth, dissemination and metastasis of drug-resistant cancer cell clones and supports the survival of drug-sensitive cancer cells, contributing to incomplete tumour regression. The tumour-promoting secretome of melanoma cells treated with the kinase inhibitor vemurafenib is driven by downregulation of the transcription factor FRA1. In situ transcriptome analysis of drug-resistant melanoma cells responding to the regressing tumour microenvironment revealed hyperactivation of several signalling pathways, most prominently the AKT pathway. Dual inhibition of RAF and the PI(3)K/AKT/mTOR intracellular signalling pathways blunted the outgrowth of the drug-resistant cell population in BRAF mutant human melanoma, suggesting this combination therapy as a strategy against tumour relapse. Thus, therapeutic inhibition of oncogenic drivers induces vast secretome changes in drug-sensitive cancer cells, paradoxically establishing a tumour microenvironment that supports the expansion of drug-resistant clones, but is susceptible to combination therapy.

Alternative transcription initiation leads to expression of a novel ALK isoform in cancer.

Activation of oncogenes by mechanisms other than genetic aberrations such as mutations, translocations, or amplifications is largely undefined. Here we report a novel isoform of the anaplastic lymphoma kinase (ALK) that is expressed in ∼11% of melanomas and sporadically in other human cancer types, but not in normal tissues. The novel ALK transcript initiates from a de novo alternative transcription initiation (ATI) site in ALK intron 19, and was termed ALK(ATI). In ALK(ATI)-expressing tumours, the ATI site is enriched for H3K4me3 and RNA polymerase II, chromatin marks characteristic of active transcription initiation sites. ALK(ATI) is expressed from both ALK alleles, and no recurrent genetic aberrations are found at the ALK locus, indicating that the transcriptional activation is independent of genetic aberrations at the ALK locus. The ALK(ATI) transcript encodes three proteins with molecular weights of 61.1, 60.8 and 58.7 kilodaltons, consisting primarily of the intracellular tyrosine kinase domain. ALK(ATI) stimulates multiple oncogenic signalling pathways, drives growth-factor-independent cell proliferation in vitro, and promotes tumorigenesis in vivo in mouse models. ALK inhibitors can suppress the kinase activity of ALK(ATI), suggesting that patients with ALK(ATI)-expressing tumours may benefit from ALK inhibitors. Our findings suggest a novel mechanism of oncogene activation in cancer through de novo alternative transcription initiation.

Atypical fibroxanthoma and pleomorphic dermal sarcoma harbor frequent NOTCH1/2 and FAT1 mutations and similar DNA copy number alteration profiles.

Atypical fibroxanthomas and pleomorphic dermal sarcomas are tumors arising in sun-damaged skin of elderly patients. They have differing prognoses and are currently distinguished using histological criteria, such as invasion of deeper tissue structures, necrosis and lymphovascular or perineural invasion. To investigate the as-yet poorly understood genetics of these tumors, 41 atypical fibroxanthomas and 40 pleomorphic dermal sarcomas were subjected to targeted next-generation sequencing approaches as well as DNA copy number analysis by comparative genomic hybridization. In an analysis of the entire coding region of 341 oncogenes and tumor suppressor genes in 13 atypical fibroxanthomas using an established hybridization-based next-generation sequencing approach, we found that these tumors harbor a large number of mutations. Gene alterations were identified in more than half of the analyzed samples in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter. The presence of these alterations was verified in 26 atypical fibroxanthoma and 35 pleomorphic dermal sarcoma samples by targeted amplicon-based next-generation sequencing. Similar mutation profiles in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter were identified in both atypical fibroxanthoma and pleomorphic dermal sarcoma. Activating RAS mutations (G12 and G13) identified in 3 pleomorphic dermal sarcoma were not found in atypical fibroxanthoma. Comprehensive DNA copy number analysis demonstrated a wide array of different copy number gains and losses, with similar profiles in atypical fibroxanthoma and pleomorphic dermal sarcoma. In summary, atypical fibroxanthoma and pleomorphic dermal sarcoma are highly mutated tumors with recurrent mutations in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter, and a range of DNA copy number alterations. These findings suggest that atypical fibroxanthomas and pleomorphic dermal sarcomas are genetically related, potentially representing two ends of a common tumor spectrum and distinguishing these entities is at present still best performed using histological criteria.

Control of triplet state generation in heavy atom-free BODIPY-anthracene dyads by media polarity and structural factors.

A family of heavy atom-free BODIPY-anthracene dyads (BADs) exhibiting triplet excited state formation from charge-transfer states is reported. Four types of BODIPY scaffolds, different in the alkyl substitution pattern, and four anthracene derivatives have been used to access BADs. Fluorescence and intersystem crossing (ISC) in these dyads depend on donor-acceptor couplings and can be accurately controlled by substitution or media polarity. Under conditions that do not allow charge transfer (CT), the dyads exhibit fluorescence with high quantum yields. Formation of charge-transfer states triggers ISC and the formation of long-lived triplet excited states in the dyads. The excited state properties were studied by steady-state techniques and ultrafast pump-probe spectroscopy to determine the parameters of the observed processes. Structural information for various BADs was derived from single crystal X-ray structure determinations alongside DFT molecular geometry optimization, revealing the effects of mutual orientation of subunits on the photophysical properties. The calculations showed that alkyl substituents on the BODIPY destabilize CT states in the dyads, thus controlling the charge transfer between the subunits. The effect of the dyad structure on the ISC efficiency was considered at the M06-2X level of theory, and a correlation between mutual orientation of the subunits and the energy gap between singlet and triplet CT states was studied using a multireference CASSCF method.

Reduced H3K27me3 expression in Merkel cell polyoma virus-positive tumors.

Merkel cell carcinoma is a primary cutaneous neuroendocrine carcinoma, which once metastatic is difficult to treat. Recent mutation analyses of Merkel cell carcinoma revealed a low number of mutations in Merkel cell polyomavirus-associated tumors, and a high number of mutations in virus-negative combined squamous cell and neuroendocrine carcinomas of chronically sun-damaged skin. We speculated that the paucity of mutations in virus-positive Merkel cell carcinoma may reflect a pathomechanism that depends on derangements of chromatin without alterations in the DNA sequence (epigenetic dysregulation). One central epigenetic regulator is the Polycomb repressive complex 2 (PRC2), which silences genomic regions by trimethylating (me3) lysine (K) 27 of histone H3, and thereby establishes the histone mark H3K27me3. Recent experimental research data demonstrated that PRC2 loss in mice skin results in the formation of Merkel cells. Prompted by these findings, we explored a possible contribution of PRC2 loss in human Merkel cell carcinoma. We examined the immunohistochemical expression of H3K27me3 in 35 Merkel cell carcinomas with pure histological features (22 primary and 13 metastatic lesions) and in 5 combined squamous and neuroendocrine carcinomas of the skin. We found a strong reduction of H3K27me3 staining in tumors with pure histologic features and virus-positive Merkel cell carcinomas. Combined neuroendocrine carcinomas had no or only minimal loss of H3K27me3 labeling. Our findings suggest that a PRC2-mediated epigenetic deregulation may play a role in the pathogenesis of virus-positive Merkel cell carcinomas and in tumors with pure histologic features.

Activating cysteinyl leukotriene receptor 2 (CYSLTR2) mutations in blue nevi.

Blue nevi are common melanocytic tumors arising in the dermal layer of the skin. Similar to uveal melanomas, blue nevi frequently harbor GNAQ and GNA11 mutations. Recently, recurrent CYSLTR2 and PLCB4 mutations were identified in uveal melanomas not harboring GNAQ or GNA11 mutations. All four genes (GNAQ, GNA11, CYSLTR2, and PLCB4) code for proteins involved in the same signaling pathway, which is activated by mutations in these genes. Given the related functional consequences of these mutations and the known genetic similarities between uveal melanoma and blue nevi, we analyzed a cohort of blue nevi to investigate whether CYSLTR2 and PLCB4 mutations occur in tumors lacking GNAQ or GNA11 mutations (as in uveal melanoma). A targeted next-generation sequencing assay covering known activating mutations in GNAQ, GNA11, CYSLTR2, PLCB4, KIT, NRAS, and BRAF was applied to 103 blue nevi. As previously reported, most blue nevi were found to harbor activating mutations in GNAQ (59%, n=61), followed by less frequent mutations in GNA11 (16%, n=17). Additionally, one BRAF (1%) and three NRAS (3%) mutations were detected. In three tumors (3%) harboring none of the aforementioned gene alterations, CYSLTR2 mutations were identified. All three CYSLTR2 mutations were the same c.386T>A, L129Q mutation previously identified in uveal melanoma that has been shown to lead to increased receptor activation and signaling. In summary, our study identifies CYSLTR2 L129Q alterations as a previously unrecognized activating mutation in blue nevi, occuring in a mutually exclusive fashion with known GNAQ and GNA11 mutations. Similar to GNAQ and GNA11 mutations, CYSLTR2 mutations, when present, are likely defining pathogenetic events in blue nevi.

SF3B1 and BAP1 mutations in blue nevus-like melanoma.

Blue nevi are melanocytic tumors originating in the cutaneous dermis. Malignant tumors may arise in association with or resembling blue nevi, so called 'blue nevus-like melanoma', which can metastasize and result in patient death. Identifying which tumors will behave in a clinically aggressive manner can be challenging. Identifying genetic alterations in such tumors may assist in their diagnosis and prognostication. Blue nevi are known to be genetically related to uveal melanomas (eg, both harboring GNAQ and GNA11 mutations). In this study, we analyzed a large cohort (n=301) of various morphologic variants of blue nevi and related tumors including tumors diagnosed as atypical blue nevi (n=21), and blue nevus-like melanoma (n=12), screening for all gene mutations known to occur in uveal melanoma. Similar to published reports, we found the majority of blue nevi harbored activating mutations in GNAQ (53%) or GNA11 (15%). In addition, rare CYSLTR2 (1%) and PLCB4 (1%) mutations were identified. EIF1AX, SF3B1, and BAP1 mutations were also detected, with BAP1 and SF3B1 R625 mutations being present only in clearly malignant tumors (17% (n=2) and 25% (n=3) of blue nevus-like melanoma, respectively). In sequencing data from a larger cohort of cutaneous melanomas, this genetic profile was also identified in tumors not originally diagnosed as blue nevus-like melanoma. Our findings suggest that the genetic profile of coexistent GNAQ or GNA11 mutations with BAP1 or SF3B1 mutations can aid the histopathological diagnosis of blue nevus-like melanoma and distinguish blue nevus-like melanoma from conventional epidermal-derived melanomas. Future studies will need to further elucidate the prognostic implications and appropriate clinical management for patients with tumors harboring these mutation profiles.

Double-Strand DNA Breaks Induced by Paracyclophane Gold(I) Complexes.

Gold(I) complexes of ClickPhos [2.2]paracyclophane ligands were synthesized in excellent yields and fully characterized by spectroscopic methods as well as X-ray crystallography. The complexes exhibit a rigid ligand backbone and a triazolyl moiety and were systematically studied with respect to their cytotoxic properties. In combination with the ionic complex [(GemPhos)Au(tht)][ClO4 ] (tht=tetrahydrothiophene), in which the gold(I) atom exhibits a distorted trigonal coordination sphere of two phosphines and a labile tht ligand, their efficiency in cytotoxicity was investigated in HeLa, MCF7, and HCT116 cells as well as in a zebrafish model. Their cytotoxicity and their mechanisms of action are different and involve apoptosis, necrosis, and DNA damage. The compounds presented herein are potent metal-based cytostatics displaying LD50 values from 3.5-38 µm in different tumor cell lines and induce double-strand DNA breaks (DSB) as shown by H2AX phosphorylation (γH2AX) at foci of DSBs.

Unilateral hearing loss in children: a retrospective study and a review of the current literature.

Despite the introduction of universal newborn hearing screening (UNHS), unilateral hearing loss (UHL) is sometimes recognized late. This diagnostic delay has adverse repercussions, given the importance of binaural hearing for the development of normal auditory processing. It is incorrect to maintain that unilateral hearing is the minimum requirement for adequate speech development and that hearing aid provision is consequently unnecessary. In our retrospective study, hearing aid provision resulted in improved directional and selective hearing (quiet and noisy environments) and, compared with their chronically ill counterparts, the children in our study displayed superior health-related quality of life (HRQoL) scores in all areas. On the basis of the results, the authors conclude that even mild hearing losses (from an auditory threshold of 30 to 40 dB) should have the opportunity for hearing aid provision. A selective literature review was conducted in PubMed and textbooks and with reference to national and international guidelines. Early diagnosis and treatment of UHL have a positive effect on verbal-cognitive, linguistic, communicative, and socio-emotional development, as demonstrated by neurophysiological studies. Among the treatment modalities with differing effects on the quality of binaural hearing, cochlear implants are now used increasingly in children with hearing loss bordering on deafness. CONCLUSION: Published evidence and clinical experience support early diagnosis and treatment. Wherever feasible, hearing aid provision before or at the end of the first year of life is recommended for children with UHL. What is Known: • Almost 30 years ago, poor academic performance was reported in children with unilateral hearing loss (UHL). • Despite improvements in treatment options, it is traditionally held that unilateral hearing is the minimum requirement for adequate speech development and hearing aid provision is unnecessary. What is New: • Academic and behavioral deficits in children with UHL may be mediated by deficiencies in the default mode network. • Published evidence supports the recommendation for hearing aid provision before or at the end of the first year of life in children with UHL.

Clinicopathologic and molecular features in cutaneous extranodal natural killer-/T-cell lymphoma, nasal type, with aggressive and indolent course.

BACKGROUND: Extranodal natural killer-/T-cell lymphoma, nasal type (ENKTCL-NT) is a highly aggressive lymphoma and prognosis is usually poor. The genetic background of primary cutaneous cases is poorly understood. OBJECTIVE: We sought to evaluate the clinicopathologic features of cutaneous ENKTCL-NT, and the prognostic significance of genomic copy number alterations. METHODS: Eight cases of cutaneous ENKTCL-NT (5 primary, 2 secondary, 1 no staging performed), including 2 patients with an unusually prolonged course of 5 and 23 years, were investigated using array comparative genomic hybridization. RESULTS: All patients presented with typical clinicopathologic features. Epstein-Barr virus was found in neoplastic cells in all specimens. Copy number alterations were detected in all 8 cases with losses on 6q (37.5% of cases) and 7p (37.5% of cases), and gains on 7q (37.5% of cases) being the most frequent. Complexity of array comparative genomic hybridization profile did not correlate with the course of the disease. However, an increase of copy number alterations was detected in sequential biopsy specimens of 1 long-term survivor. LIMITATIONS: This was a small case series retrospective study. CONCLUSION: Clinicopathologic features of cutaneous ENKTCL-NT are distinctive. Lower number of copy number alterations cannot be used as predictor for prolonged survival in cutaneous ENKTCL-NT.

TAD hierarchy restricts poised LTR activation and loss of TAD hierarchy promotes LTR co-option in cancer.

Transposable elements (TEs) are abundant in the human genome, and they provide the sources for genetic and functional diversity. The regulation of TEs expression and their functional consequences in physiological conditions and cancer development remain to be fully elucidated. Previous studies suggested TEs are repressed by DNA methylation and chromatin modifications. The effect of 3D chromatin topology on TE regulation remains elusive. Here, by integrating transcriptome and 3D genome architecture studies, we showed that haploinsufficient loss of NIPBL selectively activates alternative promoters at the long terminal repeats (LTRs) of the TE subclasses. This activation occurs through the reorganization of topologically associating domain (TAD) hierarchical structures and recruitment of proximal enhancers. These observations indicate that TAD hierarchy restricts transcriptional activation of LTRs that already possess open chromatin features. In cancer, perturbation of the hierarchical chromatin topology can lead to co-option of LTRs as functional alternative promoters in a context-dependent manner and drive aberrant transcriptional activation of novel oncogenes and other divergent transcripts. These data uncovered a new layer of regulatory mechanism of TE expression beyond DNA and chromatin modification in human genome. They also posit the TAD hierarchy dysregulation as a novel mechanism for alternative promoter-mediated oncogene activation and transcriptional diversity in cancer, which may be exploited therapeutically.

Mutations in GNA11 in uveal melanoma.

BACKGROUND: Uveal melanoma is the most common intraocular cancer. There are no effective therapies for metastatic disease. Mutations in GNAQ, the gene encoding an alpha subunit of heterotrimeric G proteins, are found in 40% of uveal melanomas. METHODS: We sequenced exon 5 of GNAQ and GNA11, a paralogue of GNAQ, in 713 melanocytic neoplasms of different types (186 uveal melanomas, 139 blue nevi, 106 other nevi, and 282 other melanomas). We sequenced exon 4 of GNAQ and GNA11 in 453 of these samples and in all coding exons of GNAQ and GNA11 in 97 uveal melanomas and 45 blue nevi. RESULTS: We found somatic mutations in exon 5 (affecting Q209) and in exon 4 (affecting R183) in both GNA11 and GNAQ, in a mutually exclusive pattern. Mutations affecting Q209 in GNA11 were present in 7% of blue nevi, 32% of primary uveal melanomas, and 57% of uveal melanoma metastases. In contrast, we observed Q209 mutations in GNAQ in 55% of blue nevi, 45% of uveal melanomas, and 22% of uveal melanoma metastases. Mutations affecting R183 in either GNAQ or GNA11 were less prevalent (2% of blue nevi and 6% of uveal melanomas) than the Q209 mutations. Mutations in GNA11 induced spontaneously metastasizing tumors in a mouse model and activated the mitogen-activated protein kinase pathway. CONCLUSIONS: Of the uveal melanomas we analyzed, 83% had somatic mutations in GNAQ or GNA11. Constitutive activation of the pathway involving these two genes appears to be a major contributor to the development of uveal melanoma. (Funded by the National Institutes of Health and others.).

Malignant dermatofibroma: clinicopathological, immunohistochemical, and molecular analysis of seven cases.

Dermatofibroma (cutaneous fibrous histiocytoma) represents a common benign mesenchymal tumor, and numerous morphological variants have been described. Some variants of dermatofibroma are characterized by an increased risk of local recurrences, and there are a few reported metastasizing cases. Unfortunately, an aggressive behavior cannot be predicted reliably by morphology at the moment, and we evaluated the value of array-comparative genomic hybridization (CGH) in this setting. Seven cases of clinically aggressive dermatofibromas were identified, and pathological and molecular features were evaluated. The neoplasms occurred in four female and in three male patients (mean age was 33 years, range 2-65 years), and arose on the shoulder, buttock, temple, lateral neck, thigh, ankle, and cheek. The size of the neoplasms ranged from 1 to 9 cm (mean: 3 cm). An infiltration of the subcutis was seen in five cases. Two neoplasms were completely excised, whereas an incomplete or marginal excision was reported in the remaining cases. Local recurrences were seen in six cases (time to the first recurrence ranged from 8 months to 9 years). Metastases were noted between 3 months and 8 years after diagnosis in six patients. Two patients died of disease, and two patients are alive with disease. Histologically, the primary tumors showed features of cellular dermatofibroma (four cases), cellular/aneurysmal dermatofibroma (one case), atypical/cellular dermatofibroma (one case), and classical dermatofibroma (one case). Mitotic figures ranged from 3 to 25 per 10 high-power fields, and focal necrosis was present in five cases. Interestingly, malignant transformation from cellular dermatofibroma to an obvious spindle cell/pleomorphic sarcoma was seen in one primary and in one recurrent neoplasm. Five neoplasms showed chromosomal aberrations by array-CGH, suggesting that these changes may represent an additional diagnostic tool in the recognition of cases of dermatofibroma with a metastatic potential.

Two-dimensional visualization of multicolor FISH-generated data as a helpful tool for the analysis and understanding of cytogenetic and chromosomal alterations in melanocytic lesions.

For the evaluation of data generated by multicolor fluorescence in situ hybridization (FISH), we present here a synergistic approach that integrates the 3 most commonly used numerical algorithms in conjunction with 2 newly devised graphic tools for data visualization, namely "signal curves" and "rhombic heat maps." These two graphic tools provide information additional to the currently used numerical algorithms and thus facilitate the recognition and compensation of inherent errors that occur with the numerical method.