Functional host-specific adaptation of the intestinal microbiome in hominids

Fine-scale knowledge of the changes in composition and function of the human gut microbiome compared that of our closest relatives is critical for understanding the evolutionary processes underlying its developmental trajectory. To infer taxonomic and functional changes in the gut microbiome across hominids at different timescales, we perform high-resolution metagenomic-based analyzes of the fecal microbiome from over two hundred samples including diverse human populations, as well as wild-living chimpanzees, bonobos, and gorillas. We find human-associated taxa depleted within non-human apes and patterns of host-specific gut microbiota, suggesting the widespread acquisition of novel microbial clades along the evolutionary divergence of hosts. In contrast, we reveal multiple lines of evidence for a pervasive loss of diversity in human populations in correlation with a high Human Development Index, including evolutionarily conserved clades. Similarly, patterns of co-phylogeny between microbes and hosts are found to be disrupted in humans. Together with identifying individual microbial taxa and functional adaptations that correlate to host phylogeny, these findings offer insights into specific candidates playing a role in the diverging trajectories of the gut microbiome of hominids. We find that repeated horizontal gene transfer and gene loss, as well as the adaptation to transient microaerobic conditions appear to have played a role in the evolution of the human gut microbiome.

Activity of loggerhead turtles during the U-shaped dive: insights using angular velocity metrics

Understanding the behavioural ecology of endangered taxa can inform conservation strategies. The activity budgets of the loggerhead turtle Caretta caretta are still poorly understood because many tracking methods show only horizontal displacement and ignore dives and associated behaviours. However, time-depth recorders have enabled researchers to identify flat, U-shaped dives (or type 1a dives) and these are conventionally labelled as resting dives on the seabed because they involve no vertical displacement of the animal. Video- and acceleration-based studies have demonstrated this is not always true. Focusing on sea turtles nesting on the Cabo Verde archipelago, we describe a new metric derived from magnetometer data, absolute angular velocity, that integrates indices of angular rotation in the horizontal plane to infer activity. Using this metric, we evaluated the variation in putative resting behaviours during the bottom phase of type 1a dives for 5 individuals over 13 to 17 d at sea during a single inter-nesting interval (over 75 turtle d in total). We defined absolute resting within the bottom phase of type 1a dives as periods with no discernible acceleration or angular movement. Whilst absolute resting constituted a significant proportion of each turtle’s time budget for this 1a dive type, turtles allocated 16-38% of their bottom time to activity, with many dives being episodic, comprised of intermittent bouts of rest and rotational activity. This implies that previously considered resting behaviours are complex and need to be accounted for in energy budgets, particularly since energy budgets may impact conservation strategies.

Dynamic optical coherence tomography shows characteristic alterations of blood vessels in malignant melanoma

BACKGROUND

Dynamic optical coherence tomography (D-OCT) allows in vivo visualization of blood vessels in the skin and in malignant tumours. Vessel patterns in malignant melanoma may be associated with tumour stage.

OBJECTIVE

The aim of this study was to describe blood vessel patterns in melanomas and to correlate them with stage.

METHODS

One hundred fifty-nine malignant melanomas were assessed in a multicentre study. Every tumour was imaged using D-OCT prior to surgery and histologic evaluation. The tumour data such as thickness and ulceration as well as the staging at primary diagnosis and a follow-up of at least 40 months resulted in a stage classification. The vessel patterns were assessed according to predefined categories, compared with healthy adjacent skin, and correlated to stage.

RESULTS

Melanomas contained more blood vessels in different patterns compared with healthy adjacent skin. In particular, irregular vascular shapes such as blobs, coils, curves and serpiginous vessels were more common in melanomas. In addition, these patterns were significantly more often found in high-risk and metastatic melanomas than in low-risk lesions.

CONCLUSION

In melanomas, the density of the blood vessels is increased, and irregular vascular patterns are more frequent. At higher stages, especially in metastatic melanomas, these atypical vessels are significantly more common.

Experimentelle Forschung an der Klinik und Poliklinik für Dermatologie und Venerologie

Seit Antritt von Prof. Dr. med. Steffen Emmert als Ordinarius der Klinik und Poliklinik für Dermatologie und Venerologie im Jahr 2015 konnte das dermatologische Forschungslabor sukzessive aufgebaut und erweitert werden. Im Einklang mit dem onkologischen Schwerpunkt der Universitätsmedizin Rostock sowie dem von der Landesregierung forcierten „Gesundheitsland Mecklenburg-Vorpommern“ wird grundlagenorientierten und translationalen Projekten nachgegangen. Das vorwiegend drittmittelfinanzierte und stetig wachsende Forschungsteam bearbeitet diverse Fragestellungen in den Bereichen der Dermato-Onkologie, Plasmamedizin und seltenen Hauterkrankungen. Inzwischen auf einem soliden Fundament stehend, befindet sich der Forschungsbereich weiterhin in einem dynamischen Entwicklungsprozess. Nicht nur personell, sondern auch thematisch und methodisch wird er derzeit durch die Integration weiterer Arbeitsgruppen unter der Leitung von Ärzten aus der Klinik ergänzt und ausgebaut. Diverse Kollaborationen an der Universitätsmedizin Rostock und im Land zeugen von einem freundlichen, unterstützenden und kollegialen Umfeld, das die Integration am Standort befördert hat.

Inhibition of Cyclin-Dependent Kinase 5: A Strategy to Improve Sorafenib Response in Hepatocellular Carcinoma Therapy

Therapeutic options for patients with advanced-stage hepatocellular carcinoma (HCC) are very limited. The only approved first-line treatment is the multi-tyrosine kinase inhibitor sorafenib, which shows low response rates and severe side effects. In particular, the compensatory activation of growth factor receptors leads to chemoresistance and limits the clinical impact of sorafenib. However, combination approaches to improve sorafenib have failed. Here we investigate the inhibition of cyclin-dependent kinase 5 (Cdk5) as a promising combination strategy to improve sorafenib response in HCC. Combination of sorafenib with Cdk5 inhibition (genetic knockdown by short hairpin RNA or CRISPR/Cas9 and pharmacologic inhibition) synergistically impaired HCC progression in vitro and in vivo by inhibiting both tumor cell proliferation and migration. Importantly, these effects were mediated by a mechanism for Cdk5: A liquid chromatography-tandem mass spectrometry-based proteomic approach revealed that Cdk5 inhibition interferes with intracellular trafficking, a process crucial for cellular homeostasis and growth factor receptor signaling. Cdk5 inhibition resulted in an accumulation of enlarged vesicles and respective cargos in the perinuclear region, considerably impairing the extent and quality of growth factor receptor signaling. Thereby, Cdk5 inhibition offers a comprehensive approach to globally disturb growth factor receptor signaling that is superior to specific inhibition of individual growth factor receptors. Conclusion: Cdk5 inhibition represents an effective approach to improve sorafenib response and to prevent sorafenib treatment escape in HCC. Notably, Cdk5 is an addressable target frequently overexpressed in HCC, and with Dinaciclib, a clinically tested Cdk5 inhibitor is readily available. Thus, our study provides evidence for clinically evaluating the combination of sorafenib and Dinaciclib to improve the therapeutic situation for patients with advanced-stage HCC.

V-ATPase inhibition increases cancer cell stiffness and blocks membrane related Ras signaling - a new option for HCC therapy

Hepatocellular carcinoma (HCC) is the fifth most frequent cancer worldwide and the third leading cause of cancer-related death. However, therapy options are limited leaving an urgent need to develop new strategies. Currently, targeting cancer cell lipid and cholesterol metabolism is gaining interest especially regarding HCC. High cholesterol levels support proliferation, membrane-related mitogenic signaling and increase cell softness, leading to tumor progression, malignancy and invasive potential. However, effective ways to target cholesterol metabolism for cancer therapy are still missing. The V-ATPase inhibitor archazolid was recently shown to interfere with cholesterol metabolism. In our study, we report a novel therapeutic potential of V-ATPase inhibition in HCC by altering the mechanical phenotype of cancer cells leading to reduced proliferative signaling. Archazolid causes cellular depletion of free cholesterol leading to an increase in cell stiffness and membrane polarity of cancer cells, while hepatocytes remain unaffected. The altered membrane composition decreases membrane fluidity and leads to an inhibition of membrane-related Ras signaling resulting decreased proliferation in vitro and in vivo. V-ATPase inhibition represents a novel link between cell biophysical properties and proliferative signaling selectively in malignant HCC cells, providing the basis for an attractive and innovative strategy against HCC.

Diagnostic accuracy of confocal microscopy imaging vs. punch biopsy for diagnosing and subtyping basal cell carcinoma

Background

In vivo reflectance confocal microscopy (RCM) is a promising non‐invasive skin imaging technique that could facilitate early diagnosis of basal cell carcinoma (BCC) instead of routine punch biopsies. However, the clinical value and utility of RCM vs. a punch biopsy in diagnosing and subtyping BCC is unknown.

Objective

To assess diagnostic accuracy of RCM vs. punch biopsy for diagnosing and subtyping clinically suspected primary BCC.

Methods

A prospective, consecutive cohort of 100 patients with clinically suspected BCC were included at two tertiary hospitals in Amsterdam, the Netherlands, between 3 February 2015 and 2 October 2015. Patients were randomized between two test‐treatment pathways: diagnosing and subtyping using RCM imaging followed by direct surgical excision (RCM one‐stop‐shop) or planned excision based upon the histological diagnosis and subtype of punch biopsy (standard care). The primary outcome was the agreement between the index tests (RCM vs. punch biopsy) and reference standard (excision specimen) in correctly diagnosing BCC. The secondary outcome was the agreement between the index tests and reference standard in correctly identifying the most aggressive BCC subtypes.

Results

Sensitivity to detect BCC was similar for RCM and punch biopsy (100% vs. 93.94%), but a punch biopsy was more specific than RCM (79% vs. 38%). RCM expert evaluation for diagnosing BCC had a sensitivity of 100% and a specificity of 75%. The agreement between RCM and excision specimen in identifying the most aggressive BCC subtype ranged from 50% to 85% vs. 77% by a punch biopsy.

Conclusion

Reflectance confocal microscopy and punch biopsy have comparable diagnostic accuracy to diagnose and subtype BCC depending on RCM experience. Although experienced RCM users could accurately diagnose BCC at a distance, we found an important difference in subtyping BCC. Future RCM studies need to focus on diagnostic accuracy, reliability and specific criteria to improve BCC subtype differentiation.

Inhibition of endothelial Cdk5 reduces tumor growth by promoting non-productive angiogenesis

Therapeutic success of VEGF-based anti-angiogenic tumor therapy is limited due to resistance. Thus, new strategies for anti-angiogenic cancer therapy based on novel targets are urgently required. Our previous in vitro work suggested that small molecule Cdk5 inhibitors affect angiogenic processes such as endothelial migration and proliferation. Moreover, we recently uncovered a substantial role of Cdk5 in the development of lymphatic vessels. Here we pin down the in vivo impact of endothelial Cdk5 inhibition in angiogenesis and elucidate the underlying mechanism in order to judge the potential of Cdk5 as a novel anti-angiogenic and anti-cancer target. By the use of endothelial-specific Cdk5 knockout mouse models and various endothelial and tumor cell based assays including human tumor xenograft models, we show that endothelial-specific knockdown of Cdk5 results in excessive but non-productive angiogenesis during development but also in tumors, which subsequently leads to inhibition of tumor growth. As Cdk5 inhibition disrupted Notch function by reducing the generation of the active Notch intracellular domain (NICD) and Cdk5 modulates Notch-dependent endothelial cell proliferation and sprouting, we propose that the Dll4/Notch driven angiogenic signaling hub is an important and promising mechanistic target of Cdk5. In fact, Cdk5 inhibition can sensitize tumors to conventional anti-angiogenic treatment as shown in tumor xenograft models. In summary our data set the stage for Cdk5 as a drugable target to inhibit Notch-driven angiogenesis condensing the view that Cdk5 is a promising target for cancer therapy.

Two-Pore Channel Function Is Crucial for the Migration of Invasive Cancer Cells

Metastatic invasion is the major cause of cancer-related deaths. In this study, we introduce two-pore channels (TPC), a recently described class of NAADP- and PI(3,5)P2-sensitive Ca²⁺-permeable cation channels in the endolysosomal system of cells, as candidate targets for the treatment of invasive cancers. Inhibition of the channel abrogated migration of metastatic cancer cells in vitro Silencing or pharmacologic inhibition of the two-pore channel TPC2 reduced lung metastasis of mammary mouse cancer cells. Disrupting TPC function halted trafficking of β1-integrin, leading to its accumulation in EEA1-positive early endosomes. As a consequence, invasive cancer cells were no longer able to form leading edges, which are required for adequate migration. Our findings link TPC to cancer cell migration and provide a preclinical proof of concept for their candidacy as targets to treat metastatic cancers. Cancer Res; 77(6); 1427-38. ©2017 AACR.

The dendritic cell high-affinity IgE receptor is overexpressed in both asthma and severe COPD

BACKGROUND

The reduction of asthma exacerbations following omalizumab treatment has been related to the suppression of the high-affinity IgE receptor (FcεRI) on plasmacytoid dendritic cells (DCs). However, the FcεRI expression on DCs in chronic obstructive pulmonary disease (COPD) is unknown.

OBJECTIVE

To compare FcεRI expression on DCs in COPD with patients with allergic asthma and healthy controls, and to relate the findings to clinical parameters, blood eosinophil concentrations and serum immunoglobin E (IgE) concentrations.

METHODS

Using four-colour flow cytometry, FcεRI expression on blood myeloid DCs and plasmacytoid DCs was analyzed in 64 patients with COPD, 20 patients with allergic asthma, 41 asymptomatic never smokers and 21 asymptomatic current smokers.

RESULTS

As compared with never smokers, current smokers displayed an increased expression of the FcεRI on myeloid and plasmacytoid DCs. In patients with COPD, the expression of the FcεRI on plasmacytoid DCs, but not myeloid DCs, increased from spirometric GOLD stage 2 to GOLD stage 4, and was correlated with several lung function parameters. Patients with severe COPD and patients with allergic asthma displayed a similar FcεRI overexpression on plasmacytoid DCs. In all groups, there was a positive correlation between total IgE serum concentrations and the FcεRI expression on plasmacytoid DCs.

CONCLUSIONS AND CLINICAL RELEVANCE

Severe COPD and allergic asthma are characterized by a similar overexpression of the high-affinity IgE receptor on plasmacytoid DCs. In view of the effect of anti-IgE on exacerbations in asthma, trials investigating the effect of anti-IgE on exacerbations in severe COPD appear to be warranted.

Anti-angiogenic effects of novel cyclin-dependent kinase inhibitors with a pyrazolo[4,3-d]pyrimidine scaffold

BACKGROUND AND PURPOSE

Cyclin-dependent kinase 5 (CDK5) has recently emerged as an attractive target in several tumour entities. Inhibition of CDK5 has been shown to have anti-angiogenic effects in vitro and in vivo. However, potent inhibitors of CDK5, which can be applied in vivo, are still scarce. We have recently developed a new series of 5-substituted 3-isopropyl-7-[4-(2-pyridyl)benzyl]amino-1(2)H-pyrazolo[4,3-d]pyrimidines that show a preference for inhibiting CDK5 and tested them in vitro and in vivo in a murine model of hepatocellular carcinoma.

EXPERIMENTAL APPROACH

All compounds were initially examined for effects on proliferation of HUVECs. The most potent compounds were then tested on migration, and one of them, LGR2674, was selected for assessing effects on nuclear fragmentation, cell cycle, cell viability and metabolic activity. Furthermore, LGR2674 was tested in a tube formation assay and in vivo in a murine model of hepatocellular carcinoma, induced by s.c. injection of HUH7 cells (measurement of in vivo toxicity, tumour vascularization, tumour cell proliferation and tumour size).

KEY RESULTS

LGR2674 showed an EC50 in the low nanomolar range in the proliferation and migration assays. Cytotoxic effects started at 50 nM, a concentration that did not influence the cell cycle. In vivo, LGR2674 was well tolerated and caused a clear reduction in vessel density in the tumours; also tumour cell proliferation was inhibited and tumour growth retarded.

CONCLUSIONS AND IMPLICATIONS

Pyrazolo[4,3-d]pyrimidine is a novel scaffold for the development of potent CDK inhibitors with in vivo potential. Such structures are good candidates for broadening our pharmacological arsenal against various tumours.

Interleukin-4 and interferon-γ orchestrate an epithelial polarization in the airways

Interferon-γ (IFN-γ) and interleukin-4 (IL-4) are key effector cytokines for the differentiation of T helper type 1 and 2 (Th1 and Th2) cells. Both cytokines induce fate-decisive transcription factors such as GATA3 and TBX21 that antagonize the polarized development of opposite phenotypes by direct regulation of each other's expression along with many other target genes. Although it is well established that mesenchymal cells directly respond to Th1 and Th2 cytokines, the nature of antagonistic differentiation programs in airway epithelial cells is only partially understood. In this study, primary normal human bronchial epithelial cells (NHBEs) were exposed to IL-4, IFN-γ, or both and genome-wide transcriptome analysis was performed. The study uncovers an antagonistic regulation pattern of IL-4 and IFN-γ in NHBEs, translating the Th1/Th2 antagonism directly in epithelial gene regulation. IL-4- and IFN-γ-induced transcription factor hubs form clusters, present in antagonistically and polarized gene regulation networks. Furthermore, the IL-4-dependent induction of IL-24 observed in rhinitis patients was downregulated by IFN-γ, and therefore IL-24 represents a potential biomarker of allergic inflammation and a Th2 polarized condition of the epithelium.

MDM2 antagonist nutlin-3a sensitizes tumors to V-ATPase inhibition

Treating cancer is one of the big challenges of this century and it has become evident that single chemotherapeutic treatment is rarely effective. As tumors often carry multiple mutations using combination therapy which addresses different targets seems therefore more beneficial. One of the most frequently mutated genes in tumors is the tumor suppressor p53. Significant work has been put in the development of p53 activators, which are now in clinical studies against diverse cancers. Recently, we could show that inhibition of V-ATPase, a multisubunit proton pump, by archazolid induces p53 protein levels in cancer cells. In this study, we provide evidence that the combination of archazolid with the p53 activator nutlin-3a is synergistically inducing cell death in different p53 wild type tumor cell lines. Mechanistically, this effect could presumably be attributed to reduction of glycolysis as TIGAR mRNA levels were increased and glucose uptake and Glut1 protein levels were reduced. In addition, combination treatment highly activated pro-apoptotic pathways including IGFBP3 and Bax inducing caspase-9 and PARP cleavage. Remarkably, combination of archazolid and nutlin-3a was more efficient in reducing tumor growth compared to single dose treatment in a U87MG mouse model in vivo. Hence, our findings suggest the combination of archazolid and nutlin-3a as a highly promising strategy for the treatment of p53 wild type tumors.

Grading keratinocyte atypia in actinic keratosis: a correlation of reflectance confocal microscopy and histopathology

BACKGROUND

Actinic Keratosis (AK) is the clinical manifestation of cutaneous dysplasia of epidermal keratinocytes, with progressive trend towards squamous cell carcinoma.

OBJECTIVE

To evaluate the strength of the correlation between keratinocyte atypia, as detected by Reflectance Confocal Microscopy (RCM) and histopathology, and to develop a more objective atypia grading scale for RCM quantification, through a discrete ranking.

METHODS

A total of 48 AKs and two control areas (photodamaged and non-photodamaged skin) were selected for this study. All these areas were documented by RCM and biopsied for histopathology. One representative image of the epidermis was selected for RCM and for histopathology and used for side-by-side comparison with purpose written software. The assessor chose which of two images displayed more keratinocyte atypia, and an ordered list from the image showing the least to the most keratinocyte atypia was generated. Three evaluations were obtained for RCM and two for histopathology.

RESULTS

Good interobserver correlation was obtained for RCM and histopathology grading, with high concordance between RCM and histopathology grading.

CONCLUSIONS

Expert rater scan consistently distinguish different grades of cytological atypia. Non-invasive RCM data from in vivo imaging can be graded for keratinocyte atypia, comparable to histopathological grading.

Update on non-invasive imaging techniques in early diagnosis of non-melanoma skin cancer

Non-melanoma skin cancer (NMSC) is the most common malignancy in fair skinned populations. Dermoscopy, reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) are non-invasive imaging techniques that play an important role in diagnosis of skin tumors. The aim of this study was to provide new insights into the role of non-invasive tecniques in the diagnosis of non-melanoma skin cancers, concentrating especially on dermoscopy, RCM and OCT. The analysis of the studies obtained from the most recent literature, taking into account previous essential reported information in this field. A search concerning the role of dermoscopy, RCM and OCT in the diagnosis of NMSC was performed on PubMed.

EXCLUSION CRITERIA

duplicated studies, single case report, and papers with language other than English New and old literature about early diagnosis of NMSC through non-invasive imaging techniques were analyzed. The role and the diagnostic accuracy of dermoscopy, RCM and OCT for the diagnosis of NMSC were reported according to the data given by literature. The development of non-invasive diagnostic devices (especially dermoscopy, RCM and OCT) allows tissue imaging in-vivo contributing to a more accurate diagnosis of skin cancer, sparing time for the patient and costs for the public health system.

The sensitivity and specificity of optical coherence tomography for the assisted diagnosis of nonpigmented basal cell carcinoma: an observational study

BACKGROUND

The diagnostic criteria for basal cell carcinoma (BCC) using optical coherence tomography (OCT) have been described previously, but the clinical value of these findings remains unknown.

OBJECTIVES

To investigate the diagnostic value of OCT for BCC in a typical clinical setting. The primary efficacy end point was a diagnosis of BCC for each lesion. Secondary end points were the diagnosis of other possible conditions.

METHODS

This was an observational, prospective, multicentre study in which consecutive patients with nonpigmented pink lesions suspicious for BCC underwent clinical assessment, dermoscopy and OCT, with the diagnosis recorded at each stage. Once all diagnoses had been recorded, the histological results were disclosed. In total 164 patients with 256 lesions were recruited. Histology was missing for 21 lesions, leaving 235 lesions in 155 patients for analysis.

RESULTS

Sixty per cent of lesions (141 of 235) were identified as BCC by histology. A slight increase of sensitivity was noted following OCT, which did not reach statistical significance. The specificity increased significantly from 28·6% by clinical assessment to 54·3% using dermoscopy and to 75·3% with the addition of OCT (P < 0·001). The positive predictive value for the diagnosis of BCC using OCT was 85·2% [95% confidence interval (CI) 78·6-90·4], and the negative predictive value was 92·1% (95% CI 83·6-97·0). The accuracy of diagnosis for all lesions increased from 65·8% with clinical evaluation to 76·2% following additional dermoscopy and to 87·4% with the addition of OCT.

CONCLUSIONS

OCT significantly improved the diagnostic specificity for BCC compared with clinical assessment and dermoscopy alone.