Pax genes: Regulators of lineage specification and progenitor cell maintenance

Pax genes encode a family of transcription factors that orchestrate complex processes of lineage determination in the developing embryo. Their key role is to specify and maintain progenitor cells through use of complex molecular mechanisms such as alternate RNA splice forms and gene activation or inhibition in conjunction with protein co-factors. The significance of Pax genes in development is highlighted by abnormalities that arise from the expression of mutant Pax genes. Here, we review the molecular functions of Pax genes during development and detail the regulatory mechanisms by which they specify and maintain progenitor cells across various tissue lineages. We also discuss mechanistic insights into the roles of Pax genes in regeneration and in adult diseases, including cancer

Genetic Factors in Metastatic Progression of Cutaneous Melanoma: the Future Role of Circulating Melanoma Cells in Prognosis and Management

The greatest potential for improvement of outcome for patients with Cutaneous Malignant Melanoma lies in the prevention of systemic metastasis. Despite extensive investigation, current prognostic indicators either alone or in combination, although related to melanoma progression, are not sufficient to accurately predict the pattern of progression and outcome for any individual patient. Metastasis related death has been recorded in patients initially diagnosed with early stage tumour as well as in patients many years after initial tumour removal. The trouble finding a predictable pattern in the puzzle of melanoma progression may be linked to the fact that most of the material studied for prognosis is either, cutaneous primaries or metastatic deposits, rather than the melanoma cells in the circulatory system which are responsible for disease progression. In this review article we discuss the potential use of circulating tumour cell (CTC) detection and quantification for identifying patients at risk of metastatic deposits. We also discuss current therapies for the treatment of metastatic melanoma and analyse how CTCs may be used to evaluate the effectiveness of current therapies and to pinpoint patients who require further treatment

Advances in personalized targeted treatment of metastatic melanoma and non-invasive tumor monitoring

Despite extensive scientific progress in the melanoma field, treatment of advanced stage melanoma with chemotherapeutics and biotherapeutics has rarely provided response rates higher than 20%. In the past decade, targeted inhibitors have been developed for metastatic melanoma, leading to the advent of more personalized therapies of genetically characterized tumors. Here we review current melanoma treatments and emerging targeted molecular therapies. In particular we discuss the mutant BRAF inhibitors Vemurafenib and Dabrafenib, which markedly inhibit tumor growth and advance patients’ overall survival. However this response is almost inevitably followed by complete tumor relapse due to drug resistance hampering the encouraging initial responses. Several mechanisms of resistance within and outside the MAPK pathway have now been uncovered and have paved theway for clinical trials of combination therapies to try and overcome tumor relapse. It is apparent that personalized treatment management will be required in this new era of targeted treatment. Circulating tumor cells (CTCs) provide an easily accessible means of monitoring patient relapse and several new approaches are available for the molecular characterization of CTCs. Thus CTCs provide a monitoring tool to evaluate treatment efficacy and early detection of drug resistance in real time.We detail here how advances in the molecular analysis of CTCs may provide insight into new avenues of approaching therapeutic options that would benefit personalized melanoma management

Circulating tumour DNA (ctDNA) as a liquid biopsy for melanoma

Circulating tumour DNA (ctDNA) has emerged as a promising blood-based biomarker for monitoring disease status of patients with advanced cancers. In melanoma, ctDNA has been shown to have clinical value as an alternative tumour source for the detection clinically targetable mutations for the assessment of response to therapy. This review provides a critical summary of the evidence that gives credence to the utility of ctDNA as a biomarker for monitoring of disease status in advanced melanoma and the steps required for its implementation into clinical settings

Melanoma circulating tumor cells: Benefits and challenges required for clinical application

The implementation of novel therapeutic interventions has improved the survival rates of melanoma patients with metastatic disease. Nonetheless, only 33% of treated cases exhibit long term responses. Circulating tumor cell (CTC) measurements are currently of clinical value in breast, prostate and colorectal cancers. However, the clinical utility of melanoma CTCs (MelCTCs) is still unclear due to challenges that appear intrinsic to MelCTCs (i.e. rarity, heterogeneity) and a lack of standardization in their isolation, across research laboratories. Here, we review the latest developments, pinpoint the challenges in MelCTC isolation and address their potential role in melanoma management

SIRT1 activation mediates heat-induced survival of UVB damaged Keratinocytes

Background Exposure to heat stress after UVB irradiation induces a reduction of apoptosis, resulting in survival of DNA damaged human keratinocytes. This heat-mediated evasion of apoptosis appears to be mediated by activation of SIRT1 and inactivation of p53 signalling. In this study, we assessed the role of SIRT1 in the inactivation of p53 signalling and impairment of DNA damage response in UVB plus heat exposed keratinocytes. Results Activation of SIRT1 after multiple UVB plus heat exposures resulted in increased p53 deacetylation at K382, which is known to affect its binding to specific target genes. Accordingly, we noted decreased apoptosis and down regulation of the p53 targeted pro-apoptotic gene BAX and the DNA repair genes ERCC1 and XPC after UVB plus heat treatments. In addition, UVB plus heat induced increased expression of the cell survival gene Survivin and the proliferation marker Ki67. Notably, keratinocytes exposed to UVB plus heat in the presence of the SIRT1 inhibitor, Ex-527, showed a similar phenotype to those exposed to UV alone; i.e. an increase in p53 acetylation, increased apoptosis and low levels of Survivin. Conclusion This study demonstrate that heat-induced SIRT1 activation mediates survival of DNA damaged keratinocytes through deacetylation of p53 after exposure to UVB plus heat

Heat-mediated reduction of apoptosis in UVB-damaged keratinocytes in vitro and in human skin ex vivo

Background: UV radiation induces significant DNA damage in keratinocytes and is a known risk factor for skin carcinogenesis. However, it has been reported previously that repeated and simultaneous exposure to UV and heat stress increases the rate of cutaneous tumour formation in mice. Since constant exposure to high temperatures and UV are often experienced in the environment, the effects of exposure to UV and heat needs to be clearly addressed in human epidermal cells. Methods: In this study, we determined the effects of repeated UVB exposure 1kJ/m2 followed by heat (39°C) to human keratinocytes. Normal human ex vivo skin models and primary keratinocytes (NHEK) were exposed once a day to UVB and/or heat stress for four consecutive days. Cells were then assessed for changes in proliferation, apoptosis and gene expression at 2days post-exposure, to determine the cumulative and persistent effects of UV and/or heat in skin keratinocytes. Results: Using ex vivo skin models and primary keratinocytes in vitro, we showed that UVB plus heat treated keratinocytes exhibit persistent DNA damage, as observed with UVB alone. However, we found that apoptosis was significantly reduced in UVB plus heat treated samples. Immunohistochemical and whole genome transcription analysis showed that multiple UVB plus heat exposures induced inactivation of the p53-mediated stress response. Furthermore, we demonstrated that repeated exposure to UV plus heat induced SIRT1 expression and a decrease in acetylated p53 in keratinocytes, which is consistent with the significant downregulation of p53-regulated pro-apoptotic and DNA damage repair genes in these cells. Conclusion: Our results suggest that UVB-induced p53-mediated cell cycle arrest and apoptosis are reduced in the presence of heat stress, leading to increased survival of DNA damaged cells. Thus, exposure to UVB and heat stress may act synergistically to allow survival of damaged cells, which could have implications for initiation skin carcinogenesis. © 2016 The Author(s)

Neuroendocrine and neurotrophic signaling in Huntington\u27s disease: Implications for pathogenic mechanisms and treatment strategies

Huntington\u27s disease (HD) is a fatal neurodegenerative disease caused by an extended polyglutamine tract in the huntingtin protein. Circadian, sleep and hypothalamic-pituitary-adrenal (HPA) axis disturbances are observed in HD as early as 15 years before clinical disease onset. Disturbances in these key processes result in increased cortisol and altered melatonin release which may negatively impact on brain-derived neurotrophic factor (BDNF) expression and contribute to documented neuropathological and clinical disease features. This review describes the normal interactions between neurotrophic factors, the HPA-axis and circadian rhythm, as indicated by levels of BDNF, cortisol and melatonin, and the alterations in these intricately balanced networks in HD. We also discuss the implications of these alterations on the neurobiology of HD and the potential to result in hypothalamic, circadian, and sleep pathologies. Measurable alterations in these pathways provide targets that, if treated early, may reduce degeneration of brain structures. We therefore focus here on the means by which multidisciplinary therapy could be utilised as a non-pharmaceutical approach to restore the balance of these pathways

Discriminant validity of the Hospital Anxiety and Depression Scale, Beck Depression Inventory (II) and Beck Anxiety Inventory to confirmed clinical diagnosis of depression and anxiety in patients with chronic obstructive pulmonary disease

The objective of this study was to investigate the discriminant validity of commonly used depresson and anxiety screening tools in order to determine the most suitable tool for patients with chronic obstructive pulmonary disease (COPD). COPD patients (n = 56) completed the Hospital Anxiety and Depression Scale (HADS), Beck Depression Inventory (BDI-II) and Beck Anxiety Inventory (BAI). These scores were compared to confirmed clinical diagnosis of depression and anxiety using the Mini Neuropsychiatric Interview. HADS depression subscale (HADS-D) sensitivity/specificity was 78/81%; BDI-II 89/77%; HADS anxiety subscale (HADS-A) 71/81%; and BAI 89/62%. HADS-D sensitivity/specificity was improved (100/83%) with the removal of Q4 \u27I feel as if I am slowed down\u27 and adjusted cut-off ( ≥.5). Removal of BDI-II Q21 \u27Loss of interest in sex\u27 with adjusted cut-off ≥ 12 resulted in similar improvement (100/79%). No problematic items were identified for HADS-A or BAI. Previously reported low sensitivity/specificity of the HADS for COPD patients was not replicated. Furthermore, simple modifications of the HADS-D markedly improved sensitivity/specificity for depression. BDI-II, HADS-A and BAI produced acceptable sensitivity/specificity unmodified. Pending further research for COPD patients we recommend continued use of the HADS-A with standard cut-off (≥8) and removal of Q4 of the HADS-D with lower cut-off ≥5

Genetic analysis of heterogeneous subsets of circulating tumour cells from high grade serous ovarian carcinoma patients

Circulating tumour cells (CTCs) are heterogenous and contain genetic information from the tumour of origin. They bear specific intra- and extra-cellular protein markers aiding in their detection. However, since these markers may be shared with other rare cells in the blood, only genetic testing can confirm their malignancy. Herein, we analyse different CTC subsets using single cell whole genome DNA sequencing to validate their malignant origin. We randomly selected putative CTCs identified by immunostaining that were isolated from 4 patients with high grade serous ovarian cancer (HGSOC) and one with benign cystadenoma. We specifically targeted CTCs positive for epithelial (CK/EpCAMpos), mesenchymal (vimentinpos), and pseudoendothelial (CK/EpCAMpos plus CD31pos) markers. We isolated these cells and performed whole genome amplification (WGA) and low-pass whole-genome sequencing (LP-WGS) for analysis of copy number alterations (CNA). Of the CK/EpCAMpos cells analysed from the HGSOC patients, 2 of 3 cells showed diverse chromosomal CNAs. However, the 4 pseudoendothelial cells (CK/EpCAMpos plus CD31pos) observed in the HGSOC cases did not carry any CNA. Lastly, two of the clusters of vimentin positive cells sequenced from those found in the benign cystadenoma case had CNA. Despite the low number of cells analysed, our results underscore the importance of genetic analysis of putative CTCs to confirm their neoplastic origin. In particular, it highlights the presence of a population of CK/EpCAMpos cells that are not tumour cells in patients with HGSOC, which otherwise would be counted as CTCs