Genomic instability, mutations and expression analysis of the tumour suppressor genes p14ARF, p15INK4b, p16INK4a and p53 in actinic keratosis

European consensus-based interdisciplinary guideline for diagnosis, treatment and prevention of actinic keratoses, epithelial UV-induced dysplasia and field cancerization on behalf of European Association of Dermato-Oncology, European Dermatology Forum, European Academy of Dermatology and Venereology and Union of Medical Specialists (Union Européenne des Médecins Spécialistes)

A collaboration of multidisciplinary experts from the European Association of Dermato-Oncology, the European Dermatology Forum, the European Academy of Dermatology and Venereology, and the European Union of Medical Specialists was formed to develop European recommendations on AK diagnosis and treatment, based on current literature and expert consensus. This guideline addresses the epidemiology, diagnostics, risk stratification and treatments in immunocompetent as well as immunosuppressed patients. Actinic keratoses (AK) are potential precursors of cutaneous squamous cell carcinoma (cSCC) and display typical histopathologic and immunohistochemical features of this malignancy in an early stage. They can develop into cSSC in situ and become invasive in a low percentage of cases. AK is the most frequent neoplasia in white populations, frequently occurring within a cancerous field induced by ultraviolet radiation. Since it cannot be predicted, which lesion will progress to cSCC and when treatment is usually recommended. The diagnosis of AK and field cancerization is made by clinical examination. Dermatoscopy, confocal microscopy, optical coherence tomography or line-field confocal-OCT can help in the differential diagnosis of AK and other skin neoplasms. A biopsy is indicated in clinically and/or dermatoscopically suspicious and/or treatment-refractory lesions. The choice of treatment depends on patients' and lesion characteristics. For single non-hyperkeratotic lesions, the treatment can be started upon patient's request with destructive treatments or topical treatments. For multiple lesions, field cancerization treatment is advised with topical treatments and photodynamic therapy. Preventive measures such as sun protection, self-examination and repeated field cancerization treatments of previously affected skin areas in high-risk patients are advised.

Ex Vivo Analysis of Cell Differentiation, Oxidative Stress, Inflammation, and DNA Damage on Cutaneous Field Cancerization

Cutaneous field cancerization (CFC) refers to a skin region containing mutated cells' clones, predominantly arising from chronic exposure to ultraviolet radiation (UVR), which exhibits an elevated risk of developing precancerous and neoplastic lesions. Despite extensive research, many molecular aspects of CFC still need to be better understood. In this study, we conducted ex vivo assessment of cell differentiation, oxidative stress, inflammation, and DNA damage in CFC samples. We collected perilesional skin from 41 patients with skin cancer and non-photoexposed skin from 25 healthy control individuals. These biopsies were either paraffin-embedded for indirect immunofluorescence and immunohistochemistry stain or processed for proteins and mRNA extraction from the epidermidis. Our findings indicate a downregulation of p53 expression and an upregulation of Ki67 and p16 in CFC tissues. Additionally, there were alterations in keratinocyte differentiation markers, disrupted cell differentiation, increased expression of iNOS and proinflammatory cytokines IL-6 and IL-8, along with evidence of oxidative DNA damage. Collectively, our results suggest that despite its outwardly normal appearance, CFC tissue shows early signs of DNA damage, an active inflammatory state, oxidative stress, abnormal cell proliferation and differentiation.

Advancements in elucidating the pathogenesis of actinic keratosis: present state and future prospects

Solar keratosis, also known as actinic keratosis (AK), is becoming increasingly prevalent. It is a benign tumor that develops in the epidermis. Individuals with AK typically exhibit irregular, red, scaly bumps or patches as a result of prolonged exposure to UV rays. These growths primarily appear on sun-exposed areas of the skin such as the face, scalp, and hands. Presently, dermatologists are actively studying AK due to its rising incidence rate in the United States. However, the underlying causes of AK remain poorly understood. Previous research has indicated that the onset of AK involves various mechanisms including UV ray-induced inflammation, oxidative stress, complex mutagenesis, resulting immunosuppression, inhibited apoptosis, dysregulated cell cycle, altered cell proliferation, tissue remodeling, and human papillomavirus (HPV) infection. AK can develop in three ways: spontaneous regression, persistence, or progression into invasive cutaneous squamous cell carcinoma (cSCC). Multiple risk factors and diverse signaling pathways collectively contribute to its complex pathogenesis. To mitigate the risk of cancerous changes associated with long-term UV radiation exposure, prompt identification, management, and prevention of AK are crucial. The objective of this review is to elucidate the primary mechanisms underlying AK malignancy and identify potential treatment targets for dermatologists in clinical settings.

Genetic Studies of Actinic Keratosis Development: Where Are We Now?

Actinic keratosis (AK) is a common precancerous skin lesion that can develop into cutaneous squamous cell carcinoma (CSCC). AK is characterized by atypical keratinocytes in the skin's outer layer and is commonly found in sun-exposed areas. Like many precancerous lesions, the development of AK is closely associated with genetic mutations. The molecular biology and transcriptional mechanisms underlying AK development are not well understood. Ultraviolet (UV) light exposure, especially UVA and UVB radiation, is a significant risk factor for AK, causing DNA damage and mutagenic effects. Besides UV exposure, comorbidities like diabetes, rheumatoid arthritis, and psoriasis may also influence AK development. AK patients have shown associations with various internal malignancies, indicating potential vulnerability in cancer-associated genes. Treatment for AK includes cryosurgery, electrodesiccation and curettage, chemotherapeutic creams, photodynamic therapy, or topical immune-modulators. Genomic studies have identified genetic aberrations in AK, with common mutations found in genes like TP53, NOTCH1, and NOTCH2. The progression from AK to CSCC involves chromosomal aberrations and alterations in oncogenes and tumor-suppressor genes. The functional relationships among these genes are not fully understood, but network analysis provides insights into their potential mechanisms. Further research is needed to enhance our understanding of AK's pathogenesis and develop novel therapeutic approaches.

Changes in hormones, Leukocyte Telomere Length (LTL), and p16INK4a expression in SM-exposed individuals in favor of the cellular senescence

Sulfur mustard (SM) is a chemical warfare agent with well-known severe toxic effects and may cause long-term debilitating injuries. We aimed to evaluate aging and longevity in Iranian SM-exposed survivors using some endocrine and molecular biomarkers for the first time. Dehydroepiandrosterone (DHEA), prolactin (PRL), cortisol, testosterone, and luteinizing hormone (LH) were measured in 289 male SM-veterans and 66 age-matched males using the ELISA method. Leukocyte Telomere Length (LTL) measurement and p16INK4a expression were measured in the peripheral blood leukocytes of 55 males who were exposed to SM. We found a significantly lower serum DHEAS level and higher serum PRL level in SM-exposed groups (without any related to the severity of lung injuries) compared to healthy controls, but no significant difference in serum levels of cortisol, testosterone, and LH. The molar ratio of DHEAS/cortisol was significantly higher in controls compared to the SM-exposed individuals especially those with severe lung damage. Some biological parameters of allostatic load score such as DHEAS and DHEAS/cortisol ratio significantly decreased long-term after the SM exposure. Additionally, we found that LTL was shorter in SM-exposed veterans rather than unexposed controls while p16INK4a gene expression significantly increased in these groups. It seems that DHEAS, DHEAS/cortisol ratio, LTL, and p16INK4a gene expression have changed significantly in favor of cellular senescence in SM-exposed patients. Therefore, it seems that SM exposure increases biological age compared to chronological age in SM-exposed survivors.

Oral Papillomatosis: Its Relation with Human Papilloma Virus Infection and Local Immunity—An Update

Oral papilloma lesions may appear as a result of HPV infection, or not, and only special molecular methods could differentiate them. Low-risk and high-risk HPV types could induce oral HPV papillomatosis with different natural evolution, clearance and persistence mechanisms. The pathogenic mechanisms are based on the crosstalk between the oral epithelial and immune cells and this very efficient virus. HPV acts as a direct inducer in the process of transforming a benign lesion into a malignant one, the cancerization process being also debated in this paper. According to the degree of malignity, three types of papillomatous lesions can be described in the oral cavity: benign lesions, potential malign disorders and malignant lesions. The precise molecular diagnostic is important to identify the presence of various virus types and also the virus products responsible for its oncogenicity. An accurate diagnostic of oral papilloma can be established through a good knowledge of etiological and epidemiological factors, clinical examination and laboratory tests. This review intends to update the pathogenic mechanisms driving the macroscopic and histological features of oral papillomatosis having HPV infection as the main etiological factor, focusing on its interreference in the local immunity. In the absence of an accurate molecular diagnostic and knowledge of local immunological conditions, the therapeutic strategy could be difficult to decide.

Mesoporous silica nano-adjuvant triggers pro-inflammatory responses in Caco-2/peripheral blood mononuclear cell (PBMC) co-cultures

The aim of this study was to evaluate the cytotoxicity and immune-stimulatory effect of Mesoporous silica nanoparticle (MSN) Nano-adjuvant on pro-inflammatory cytokines and pattern recognition receptors (PRR) genes expression in Caco-2/PBMC co-culture model. MSNs were synthesized and characterized by scanning electron microscope (SEM), Brunauer Emmett Teller (BET) and Barrett Joyner Halenda (BJH) techniques. The BET specific surface area of MSNs was around 947 m²/g and the total pore volume and average pore diameter were 1.5 cm³/g and 8.01 nm, respectively. At the concentration of 10 µg/mL, MSN showed a low and time-dependent cytotoxicity on Caco-2 cells, while no cytotoxic effect was observed for 0.1 and 1 µg/mL concentrations after 24, 48 and 72 h. The expression of pro-inflammatory cytokines genes (IL-1, IL-8 and TNF-α) in co-cultures treated with different concentrations of MSN showed a dose-dependent significant increase up to 17.44, 2.722 and 4.34 folds, respectively, while the expression augmentation of IL-1 gene was significantly higher than the others. This indicates slight stimulation of intestinal inflammation. Different concentrations of MSN significantly increased TLR4 and NOD2 expression to 4.14 and 2.14 folds, respectively. NOD1 was not affected significantly. It can be concluded that MSN might increase protective immune responses against antigens as a vaccine adjuvant candidate. It seems that stimulation of TNF-α, IL-1, and IL-8 expression in enterocytes probably transpires through the agonistic activity of MSN for TLRs including TLR4, while NOD2-associated signaling pathways are also involved. This study provides an overall picture of MSN as a novel and potent oral adjuvant for mucosal immunity.

Molecular Mechanisms of Cutaneous Squamous Cell Carcinoma

Non-melanoma skin cancers are cutaneous malignancies representing the most common form of cancer in the United States. They are comprised predominantly of basal cell carcinomas and squamous cell carcinomas (cSCC). The incidence of cSCC is increasing, resulting in substantial morbidity and ever higher treatment costs; currently in excess of one billion dollars, per annum. Here, we review research defining the molecular basis and development of cSCC that aims to provide new insights into pathogenesis and drive the development of novel, cost and morbidity saving therapies.

Guidelines of care for the management of actinic keratosis

BACKGROUND

Actinic keratoses (AK) are rough scaly patches that arise on chronically ultraviolet-exposed skin and can progress to keratinocyte carcinoma.

OBJECTIVE

This analysis examined the literature related to the management of AK to provide evidence-based recommendations for treatment. Grading, histologic classification, natural history, risk of progression, and dermatologic surveillance of AKs are also discussed.

METHODS

A multidisciplinary Work Group conducted a systematic review to address 5 clinical questions on the management of AKs and applied the Grading of Recommendations, Assessment, Development, and Evaluation approach for assessing the certainty of the evidence and formulating and grading clinical recommendations. Graded recommendations were voted on to achieve consensus.

RESULTS

Analysis of the evidence resulted in 18 recommendations.

LIMITATIONS

This analysis is based on the best available evidence at the time it was conducted. The pragmatic decision to limit the literature review to English language randomized trials may have excluded data published in other languages or limited identification of relevant long-term follow-up data.

CONCLUSIONS

Strong recommendations are made for using ultraviolet protection, topical imiquimod, topical 5-fluorouracil, and cryosurgery. Conditional recommendations are made for the use of photodynamic therapy and diclofenac for the treatment of AK, both individually and as part of combination therapy regimens.

Vitamin D Supplementation Improves Cognitive Function Through Reducing Oxidative Stress Regulated by Telomere Length in Older Adults with Mild Cognitive Impairment: A 12-Month Randomized Controlled Trial

BACKGROUND

Cognitive decline in older adults is a serious public health problem today. Association between vitamin D supplementation and cognition remains controversial.

OBJECTIVE

To determine whether a 12-month vitamin D supplementation improves cognitive function in elderly subjects with mild cognitive impairment (MCI), and whether it is mediated through the mechanism in which telomere length (TL) regulate oxidative stress.

METHODS

This was a double-blind, randomized, placebo-controlled trial in Tianjin, China. Participants were all native Chinese speakers aged 65 years and older with MCI. 183 subjects were randomized to an intervention group (vitamin D 800 IU/day, n = 93) or a placebo group (the matching starch granules, n = 90), and followed up for 12 months. Tests of cognitive function and mechanism-related biomarkers were evaluated at baseline, 6 months, and 12 months.

RESULTS

Repeated-measures ANOVA showed substantial improvements in the full scale intelligence quotient (FSIQ), information, digit span, vocabulary, block design, and picture arrangement scores in the vitamin D group over the placebo group (p < 0.001). Leukocyte TL was significantly higher, while serum 8-OXO-dG, OGG1mRNA, and P16INK4amRNA revealed greater decreases in the vitamin D group over the placebo group (p < 0.001). According to mixed-model repeated-measures ANOVA analysis, vitamin D group showed a significant enhancement in the FSIQ score for 12 months compared with the control (estimate value = 5.132, p < 0.001).

CONCLUSION

Vitamin D supplementation for 12 months appears to improve cognitive function through reducing oxidative stress regulated by increased TL in order adults with MCI. Vitamin D may be a promising public health strategy to prevent cognitive decline.

The Genomic Landscape of Actinic Keratosis

Actinic keratoses (AKs) are lesions of epidermal keratinocyte dysplasia and are precursors for invasive cutaneous squamous cell carcinoma (cSCC). Identifying the specific genomic alterations driving the progression from normal skin to skin with AK to skin with invasive cSCC is challenging because of the massive UVR-induced mutational burden characteristic at all stages of this progression. In this study, we report the largest AK whole-exome sequencing study to date and perform a mutational signature and candidate driver gene analysis on these lesions. We demonstrate in 37 AKs from both immunosuppressed and immunocompetent patients that there are significant similarities between AKs and cSCC in terms of mutational burden, copy number alterations, mutational signatures, and patterns of driver gene mutations. We identify 44 significantly mutated AK driver genes and confirm that these genes are similarly altered in cSCC. We identify azathioprine mutational signature in all AKs from patients exposed to the drug, providing further evidence for its role in keratinocyte carcinogenesis. cSCCs differ from AKs in having higher levels of intrasample heterogeneity. Alterations in signaling pathways also differ, with immune-related signaling and TGFβ signaling significantly more mutated in cSCC. Integrating our findings with independent gene expression datasets confirms that dysregulated TGFβ signaling may represent an important event in AK‒cSCC progression.

Vibrio cholerae toxin coregulated pilus provokes inflammatory responses in Coculture model of Caco-2 and peripheral blood mononuclear cells (PBMC) leading to increased colonization

The aim of this study was to assess the modulatory effect of TcpA in the expression of CEACAM1 adhesin molecule and IL-1, IL-8, and TNF-α pro-inflammatory cytokines in the Coculture model of Caco-2/PBMC (peripheral blood mononuclear cell) that can mimic the intestinal milieu. The TcpA gene from Vibrio cholerae ATCC14035 was cloned in pET-28a and transformed into Escherichia coli Bl-21. The recombinant TcpA-His6 protein was expressed and purified using Ni-column chromatography. The sequencing of transformed plasmid and Western blot analysis of purified protein confirmed the identity of rTcp. The cytotoxicity of different concentrations of recombinant protein for human colon carcinoma cell line (human colorectal adenocarcinoma cell [Caco-2 cell]) was assessed by MTT assay and showed viability of 92%, 82%, and 70%, for 10 µg/mL of TcpA after 24, 48, and 72 h, respectively. Co-cultures of Caco-2 and PBMCs were used to mimic the intestinal milieu and treated with different concentrations of rTcpA (1, 5, 10, and 50 µg/mL). Our data showed about 2.04-, 3.37-, 3.68-, and 42.7-fold increase in CEACAM1 gene expression, respectively, compared with the nontreated Caco-2/PBMC Coculture. Moreover, the expression of IL-1, IL-8, and TNF-α genes was significantly increased up to 15.75-, 7.04-, and 80.95-folds, respectively. In conclusion, V. cholerae TcpA induces statistically significant dose-dependent stimulatory effect on TNF-α, IL-,1, and IL-8 pro-inflammatory cytokines expression. Of these, TNF-α was much more affected which, consequently, elevated the CEACAM1 expression level in IECs. This suggests that TcpA protein is a critical effector as an inducer of increased adhesion potential of V. cholera as well as inflammatory responses of host intestinal tissue.

Invasive squamous cell carcinomas and precursor lesions on UV-exposed epithelia demonstrate concordant genomic complexity in driver genes

Although squamous cell carcinomas (SCC) are the most frequent human solid tumor at many anatomic sites, the driving molecular alterations underlying their progression from precursor lesions are poorly understood, especially in the context of photodamage. Therefore, we used high-depth, targeted next-generation sequencing (NGS) of RNA and DNA from routine tissue samples to characterize the progression of both well- (cutaneous) and poorly (ocular) studied SCCs. We assessed 56 formalin-fixed paraffin-embedded (FFPE) cutaneous lesions (n = 8 actinic keratosis, n = 30 carcinoma in situ [CIS], n = 18 invasive) and 43 FFPE ocular surface lesions (n = 2 conjunctival/corneal intraepithelial neoplasia, n = 20 CIS, n = 21 invasive), from institutions in the US and Brazil. An additional seven cases of advanced cutaneous SCC were profiled by hybrid capture-based NGS of >1500 genes. The cutaneous and ocular squamous neoplasms displayed a predominance of UV-signature mutations. Precursor lesions had highly similar somatic genomic landscapes to SCCs, including chromosomal gains of 3q involving SOX2, and highly recurrent mutations and/or loss of heterozygosity events affecting tumor suppressors TP53 and CDKN2A. Additionally, we identify a novel molecular subclass of CIS with RB1 mutations. Among TP53 wild-type tumors, human papillomavirus transcript was detected in one matched pair of cutaneous CIS and SCC. Amplicon-based whole-transcriptome sequencing of select 20 cutaneous lesions demonstrated significant upregulation of pro-invasion genes in cutaneous SCCs relative to precursors, including MMP1, MMP3, MMP9, LAMC2, LGALS1, and TNFRSF12A. Together, ocular and cutaneous squamous neoplasms demonstrate similar alterations, supporting a common model for neoplasia in UV-exposed epithelia. Treatment modalities useful for cutaneous SCC may also be effective in ocular SCC given the genetic similarity between these tumor types. Importantly, in both systems, precursor lesions possess the full complement of major genetic changes seen in SCC, supporting non-genetic drivers of invasiveness.

DNA Methylation in Epidermal Differentiation, Aging, and Cancer

The formation and maintenance of the epidermis depend on epidermal stem cell differentiation and must be tightly regulated. Epigenetic mechanisms such as DNA methylation allow the precise gene expression cascade needed during cellular differentiation. However, these mechanisms become deregulated during aging and tumorigenesis, where cellular function and identity become compromised. Here we provide a review of this rapidly developing field. We discuss recent discoveries related to epidermal homeostasis, aging, and cancer, including the functional role of DNA methyltransferases, the methylation clock, and the determination of tumor cells-of-origin. Finally, we focus on future advances, greatly influenced by single-cell sequencing technologies.

Gene Expression Patterns of Cutaneous Squamous Cell Carcinoma and Actinic Keratosis: Biomarkers Screening for Skin Disease Diagnosis

Background

Actinic keratosis (AK) was an intraepidermal tumor which caused by ultraviolet irradiation-induced skin damage.

Objective

The aim was to screen biomarkers for development of skin disease by comparing the gene expression profiles between cutaneous squamous cell carcinoma (CSCC) and AK.

Methods

GSE45216 with 30 cutaneous squamous cell carcinoma patients and 10 actinic keratosis patients were downloaded and significance analysis of microarrays was processed to screen differently expressed genes (DEGs). Fisher's exact test was processed for DEGs enrichment. Pathway relationship network systematically reflected the signal conduction and synergism between enriched pathways based on Kyoto Encyclopedia of Genes and Genomes database. Gene co-expression network was constructed according to gene expression data. Quantitative real-time-PCR was used to verify screened biomarkers.

Results

Total 410 DEGs were screened and enriched into various functions, such as signal transduction and negative regulation of apoptotic process. They also participated into cytokine-cytokine receptor interaction and focal adhesion. The pathway relationship network was constructed with 27 nodes. Hub nodes with higher degree of this network were mitogen-activated protein kinase signaling pathway and apoptosis. The gene co-expression network was constructed with 39 nodes. Thereinto, hub node was ELOVL fatty acid elongase. The expression levels of ELOVL4 and HPGD were significantly higher in CSCC samples than that in AK samples, while the expression levels of INHBA and LAMC2 in CSCC samples were significantly lower than that in AK samples.

Conclusion

These screened genes, including ELOVL4, HPGD, INHBA and LAMC2, played important roles in transformation from AK to CSCC.

Activation of S6 signaling is associated with cell survival and multinucleation in hyperplastic skin after epidermal loss of AURORA-A Kinase

The role of mitosis in the progression of precancerous skin remains poorly understood. To address this question, we deleted the mitotic Kinase Aurora-A (Aur-A) in hyperplastic mutant p53 mouse skin as an experimental tool to study the G2/M transition in precancerous keratinocytes and AUR-A's role in this process. Epidermal Aur-A deletion (Aur-A^epiΔ) led to marked keratinocyte enlargement, pleomorphism, multinucleation, and  attenuated induction of cell death. This phenotype was characteristic of slippage after a stalled mitosis. We also observed altered or impaired epidermal differentiation, indicative of a partial skin barrier defect. The upregulation of mTOR/PI3K signaling was implicated as a mechanism by which keratinocytes may evade cell death after AUR-A deficiency. This was evidenced by the ectopic expression of the pathway readout, p-S6, in the basal layer of Aur-A^epiΔ skin and its mitotic upregulation in isolated keratinocytes. We further tested whether our findings were extended to skin carcinoma cells. The chemical inhibition of AUR-A led to a similar mitotic delay, polyploidy/multinucleation, and attenuated cell death in skin cancer cell lines. Moreover, inhibition of mTOR/PI3K signaling ameliorated the effects caused by the deficiency of AUR-A activity but was also associated with the persistence of mitotic p-S6 detection in surviving cancer cells. These results show the induction of multinucleation/polyploidy may be a compensatory state in keratinocytes that allows for cellular survival and maintenance of partial barrier function in face of aberrant cell division or differentiation. Moreover, mTOR/PI3K signaling is active in the mitosis of hyperplastic keratinocytes expressing mutant p53 and is further enhanced by stalled mitosis, indicating a potential resistance mechanism to the use of anti-mitotic drugs in the treatment of skin cancers.

DNA damage and telomere length shortening in the peripheral blood leukocytes of 20 years SM-exposed veterans

Sulfur mustard (SM) is a vesicant chemical warfare agent, and a very potent alkylating agent. SM exerts its cytotoxicity via direct alkylation of biomacromolecules, and overproduction of reactive oxygen species (ROS). Previous studies have shown that SM-induced oxidative stress has adverse effects on antioxidant defense system, and damages lipids and proteins. The aim of this study was to investigate the effect of SM-induced oxidative stress on DNA damage, and cellular senescence in SM-exposed victims. For this purpose, MDA levels as a measure of oxidative stress in the serum, 8-oxo-dG content of the genomic DNA, and OGG1 expression as two biomarkers of oxidative DNA damage, as well as, telomere length, and p16^INK4a expression as two biomarkers of cellular senescence were measured in the peripheral blood leukocytes of 215 males who were exposed to SM 20 to 25 years ago, and 53 unexposed healthy males as the control group. Our results indicated that the levels of 8-oxo-dG, and OGG1 mRNA expression were significantly higher in SM-exposed individuals. Furthermore, a significant increase in the expression of p16^INK4a was observed in SM-exposed patients, and leukocyte telomere length (LTL) was also significantly shorter in severe/very severe cases of SM-exposed patients when compared with unexposed controls. In conclusion, our data indicate that oxidative DNA damage is higher in SM-exposed patients, and their immune system has subjected to cellular senescence.

Genetic alterations in seborrheic keratoses

Seborrheic keratoses are common benign epidermal lesions that are associated with increased age and sun-exposure. Those lesions despite harboring multiple somatic alterations in contrast to malignant tumors appear to be genetically stable. In order to investigate and characterize the presence of recurrent mutations, we performed exome sequencing on DNA from one seborrheic keratosis lesion and corresponding blood cells from the same patients with follow up investigation of alterations identified by exome sequencing in 24 additional lesions from as many patients. In addition we investigated alterations in all lesions at specific genes loci that included FGFR3, PIK3CA, HRAS, BRAF, CDKN2A and TERT and DHPH3 promoters. The exome sequencing data indicated three mutations per Mb of the targeted sequence. The mutational pattern depicted typical UV signature with majority of alterations being C>T and CC>TT base changes at dipyrimidinic sites. The FGFR3 mutations were the most frequent, detected in 12 of 25 (48%) lesions, followed by the PIK3CA (32%), TERT promoter (24%) and DPH3 promoter mutations (24%). TERT promoter mutations associated with increased age and were present mainly in the lesions excised from head and neck. Three lesions also carried alterations in CDKN2A. FGFR3, TERT and DPH3 expression did not correlate with mutations in the respective genes and promoters; however, increased FGFR3 transcript levels were associated with increased FOXN1 levels, a suggested positive feedback loop that stalls malignant progression. Thus, in this study we report overall mutation rate through exome sequencing and show the most frequent mutations seborrheic keratosis.

Epithelial derived-matrix metalloproteinase (MMP9) exhibits a novel defensive role of tumor suppressor in colitis associated cancer by activating MMP9-Notch1-ARF-p53 axis

Colitis associated cancer (CAC) is chronic inflammation driven colon cancer, prevalent among individuals with Inflammatory Bowel Disease. Matrix-metalloproteinase (MMP9) is one of the essential regulators of extra cellular matrix components. We have shown that MMP9 is protective in CAC contrary to its inflammatory role in acute-colitis. Aim of our study is to identify the mechanism of the protective role of epithelial derived-MMP9 in CAC. We used homozygous transgenic mice constitutively-expressing MMP9 in colonic-epithelium (TgM9) and wild-type (WT) littermates for in vivo experiments. Stably-transfected HCT116 with/without MMP9, and mouse embryonic-fibroblasts (WT and MMP9^−/−, MEFs) were used for in vitro experiments. TgM9 mice exhibited less tumor burden, increased apoptosis, and increased expressions of active-Notch1, p53, p21^WAF1/Cip1, caspase-3 and cyclin E in CAC compared to WTs. These results were supported by MEFs data. HCT116-cells overexpressing MMP9 indicated decreased cell proliferation, S-phase cell-cycle arrest and less DNA damage compared to vector. MMP9^−/− mice showed attenuation of MMP9 was directly associated with p19ARF. Our study identifies the tumor suppressor role of epithelial derived-MMP9 in CAC via novel mechanistic pathway “MMP9-Notch1-ARF-p53 axis” regulating apoptosis, cell-cycle arrest and DNA damage implying, that MMP9 expression might be a natural/biological way to suppress colonic ulceration due to chronic inflammation.

Methylation profiling identifies two subclasses of squamous cell carcinoma related to distinct cells of origin

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer and usually progresses from a UV-induced precancerous lesion termed actinic keratosis (AK). Despite various efforts to characterize these lesions molecularly, the etiology of AK and its progression to cSCC remain partially understood. Here, we use Infinium MethylationEPIC BeadChips to interrogate the DNA methylation status in healthy, AK and cSCC epidermis samples. Importantly, we show that AK methylation patterns already display classical features of cancer methylomes and are highly similar to cSCC profiles. Further analysis identifies typical features of stem cell methylomes, such as reduced DNA methylation age, non-CpG methylation, and stem cell-related keratin and enhancer methylation patterns. Interestingly, this signature is detected only in half of the samples, while the other half shows patterns more closely related to healthy epidermis. These findings suggest the existence of two subclasses of AK and cSCC emerging from distinct keratinocyte differentiation stages.

Mutational Analysis of the BRAF Gene in Transitional Cell Carcinoma of the Bladder

Purpose

Mutational activation of the MAP kinase pathway is frequently found in many types of cancer. Recently, activating mutations in the BRAF gene, an important activator of this pathway, have been described in several tumor types including melanoma, colorectal and papillary thyroid cancer. The most frequent mutation in exon 15 (V600E) as well as several other mutations within exons 11 and 15 result in constitutive activation of the oncoprotein.

Materials and methods

Our study aimed to investigate BRAF mutations in 30 human bladder tumors and their adjacent normal tissues. The V600E mutation was screened by PCR/RFLP and exons 11, 14 and 15 of BRAF including intron-exon boundaries were sequenced.

Results

We detected two tumor specimens bearing two different mutations, both of which were found in exon 15. One sample showed the T1799A (V600E) and the other the G1798T (V600L) mutation. The first specimen was stage pT1a and grade II, whereas the second was stage pT2b and grade III. No mutations within the coding region of exons 11, 14, 15 and the intron-exon junctions for the remaining samples were found.

Conclusions

Our results suggest that involvement of BRAF mutations in the development of transitional cell carcinoma of the bladder is infrequent.

Defining the actinic keratosis field: a literature review and discussion

Despite the chronic and increasingly prevalent nature of actinic keratosis (AK) and existing evidence supporting assessment of the entire cancerization field during clinical management, a standardized definition of the AK field to aid in the understanding and characterization of the disease is lacking. The objective of this review was to present and appraise the available evidence describing the AK cancerization field, with the aim of determining a precise definition of the AK field in terms of its molecular (including genetic and immunological), histological and clinical characteristics. Eight European dermatologists collaborated to conduct a review and expert appraisal of articles detailing the characteristics of the AK field. Articles published in English before August 2016 were identified using PubMed and independently selected for further assessment according to predefined preliminary inclusion and exclusion criteria. In addition, a retrospective audit of patients with AK was performed to define the AK field in clinical terms. A total of 32 review articles and 47 original research articles provided evidence of sun-induced molecular (including genetic and immunological) and histological skin changes in the sun-exposed area affected by AK. However, the available literature was deemed insufficient to inform a clinical definition of the AK field. During the retrospective audit, visible signs of sun damage in 40 patients with AK were assessed. Telangiectasia, atrophy and pigmentation disorders emerged as 'reliable or very reliable' indicators of AK field based on expert opinion, whereas 'sand paper' was deemed a 'moderately reliable' indicator. This literature review has revealed a significant gap of evidence to inform a clinical definition of the AK field. Therefore, the authors instead propose a clinical definition of field cancerization based on the identification of visible signs of sun damage that are reliable indicators of field cancerization based on expert opinion.

Loss of DIP2C in RKO cells stimulates changes in DNA methylation and epithelial-mesenchymal transition

Background

The disco-interacting protein 2 homolog C (DIP2C) gene is an uncharacterized gene found mutated in a subset of breast and lung cancers. To understand the role of DIP2C in tumour development we studied the gene in human cancer cells.

Methods

We engineered human DIP2C knockout cells by genome editing in cancer cells. The growth properties of the engineered cells were characterised and transcriptome and methylation analyses were carried out to identify pathways deregulated by inactivation of DIP2C. Effects on cell death pathways and epithelial-mesenchymal transition traits were studied based on the results from expression profiling.

Results

Knockout of DIP2C in RKO cells resulted in cell enlargement and growth retardation. Expression profiling revealed 780 genes for which the expression level was affected by the loss of DIP2C, including the tumour-suppressor encoding CDKN2A gene, the epithelial-mesenchymal transition (EMT) regulator-encoding ZEB1, and CD44 and CD24 that encode breast cancer stem cell markers. Analysis of DNA methylation showed more than 30,000 sites affected by differential methylation, the majority of which were hypomethylated following loss of DIP2C. Changes in DNA methylation at promoter regions were strongly correlated to changes in gene expression, and genes involved with EMT and cell death were enriched among the differentially regulated genes. The DIP2C knockout cells had higher wound closing capacity and showed an increase in the proportion of cells positive for cellular senescence markers.

Conclusions

Loss of DIP2C triggers substantial DNA methylation and gene expression changes, cellular senescence and epithelial-mesenchymal transition in cancer cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3472-5) contains supplementary material, which is available to authorized users.

MicroRNA-149 is epigenetically silenced tumor-suppressive microRNA, involved in cell proliferation and downregulation of AKT1 and cyclin D1 in human glioblastoma multiforme

Aberrant DNA methylation has been shown to inactivate tumor suppressor genes during carcinogenesis. MicroRNA-149 (miR-149) was recently demonstrated to function as a tumor suppressor gene in glioblastoma multiforme (GBM). However, the potential linkage of miR-149 levels and the underlying epigenetic regulatory mechanism in human GBM has not been studied. We used quantitative real-time polymerase chain reaction to investigate the levels of miR-149 in GBM tissues, their matched adjacent normal tissues, and glioblastoma U87MG cell line. Using bisulfite genomic sequencing technology, DNA methylation status of upstream region of miR-149 was evaluated in study population groups and the U87MG cell line. After treatment of cells with 5-aza-2′-deoxycitidine (5-aza-dC), the DNA methylation status, gene expression, and target protein levels of miR-149 were investigated. Our studies revealed that methylation and expression levels of miR-149 were significantly increased and decreased, respectively in GBM patients relative to the adjacent normal tissues (P < 0.01). MiR-149 suppressed the expression of AKT1 and cyclin D1 and reduced the proliferative activities of the U87MG cell line. Treatment of U87MG cells with 5-aza-dC reversed the hypermethylation status of miR-149, enhanced the expression of its gene, and decreased target mRNA and proteins levels (P < 0.01). These findings suggest that the methylation mechanism is associated with decreased expression levels of miR-149, which may in turn lead to the increased levels of its oncogenic target proteins.

Cross-species identification of genomic drivers of squamous cell carcinoma development across preneoplastic intermediates

Cutaneous squamous cell carcinoma (cuSCC) comprises 15-20% of all skin cancers, accounting for over 700,000 cases in USA annually. Most cuSCC arise in association with a distinct precancerous lesion, the actinic keratosis (AK). To identify potential targets for molecularly targeted chemoprevention, here we perform integrated cross-species genomic analysis of cuSCC development through the preneoplastic AK stage using matched human samples and a solar ultraviolet radiation-driven Hairless mouse model. We identify the major transcriptional drivers of this progression sequence, showing that the key genomic changes in cuSCC development occur in the normal skin to AK transition. Our data validate the use of this ultraviolet radiation-driven mouse cuSCC model for cross-species analysis and demonstrate that cuSCC bears deep molecular similarities to multiple carcinogen-driven SCCs from diverse sites, suggesting that cuSCC may serve as an effective, accessible model for multiple SCC types and that common treatment and prevention strategies may be feasible.

Expression of G1/S-cyclins and cyclin-dependent kinase inhibitors in actinic keratosis and squamous cell carcinoma

BACKGROUND

Actinic keratosis (AK) and Bowen's disease (squamous cell carcinoma in situ, SCCIS) are pre-invasive stages in the development of squamous cell carcinoma (SCC).

METHODS

Immunohistochemical study of cyclin D1, cyclin E, p16(INK4a) and p21(Cip1) (/Waf1) in AK (53 cases), SCCIS (16 cases) and SCC (40 cases), in relation to the type of the lesion and SCC prognostic parameters (grade, diameter and thickness).

RESULTS

Diffuse cyclin D1 distribution was more frequent in SCCIS and SCC than in AK (p = 0.03) and similar pattern was observed for p16(INK4a) . For cyclin E, central distribution dominated in SCC compared with the AK (p = 0.001) and SCCIS (p = 0.03). p21(Cip1) (/Waf1) displayed suprabasal distribution more frequently in AK than in SCCIS (p = 0.001) and SCC (p = 0.0004). Semiquantitative assessment showed more positive cells in AK (p = 0.04) and SCCIS (p = 0.04) than in SCC for cyclin E. SCC with diameter over 20 mm and those thicker than 6 mm revealed higher labeling index with p16(INK4a) and p21(Cip1) (/Waf1) , respectively.

CONCLUSIONS

Our results suggest different alterations for p16(INK4a) and p21(Cip1) (/Waf1) in AK, SCCIS and SCC. Immunostaining distribution showed closer correlation with the type of the lesion, whereas percentage of positive cells displayed better association with the SCC prognostic parameters.

How to treat actinic keratosis? An update

Actinic keratosis (AKs) is one of the most common skin lesions leading to an increased risk of developing squamous cell carcinoma and other skin malignancies. The lesions principally arise as a result of excessive ultraviolet (UV) exposure. AKs may regress spontaneously, remain stable or evolve to invasive squamous cell carcinoma. The risk of squamous cell carcinoma is significantly increased patients with more than 5 AKs. The main mechanisms involved in the formation of AK are inflammation, mutagenesis, oxidative stress, impaired apoptosis, immunosuppression, disregulation of cell growth and proliferation, and tissue remodeling. Human papilloma virus has also been correlated with the formation of some AKs. As an individual ages, his skin is exposed to increasing cumulative amounts of UV light and other environmental insults. This is especially true for the head, neck and forearms. These insults do not target only the skin where individual lesions develop, but also the surrounding area. In this area undetectable preclinical AK lesions or dysplastic cells may be present. The whole affected area is known as the 'field'. Therefore, management is divided into lesion-directed and field-directed therapies. Currently, the therapies in use are lesion-directed cryotherapy and/or excision, and field-directed topical agents: 5-fluorouracil, diclofenac, photodynamic therapy, imiquimod, and ingenol mebutate. Combining lesion- and field-directed therapies showed good results and several novel therapies are under investigation. Treatment is variable and personalized, what makes a gold standard management algorithm difficult to design. This review aims to describe the rationale behind the available treatment options for AKs based on current understanding of pathophysiology and epidemiology.

Identification of Cyclobutane Pyrimidine Dimer-Responsive Genes Using UVB-Irradiated Human Keratinocytes Transfected with In Vitro-Synthesized Photolyase mRNA

Major biological effects of UVB are attributed to cyclobutane pyrimidine dimers (CPDs), the most common photolesions formed on DNA. To investigate the contribution of CPDs to UVB-induced changes of gene expression, a model system was established by transfecting keratinocytes with pseudouridine-modified mRNA (Ψ-mRNA) encoding CPD-photolyase. Microarray analyses of this model system demonstrated that more than 50% of the gene expression altered by UVB was mediated by CPD photolesions. Functional classification of the gene targets revealed strong effects of CPDs on the regulation of the cell cycle and transcriptional machineries. To confirm the microarray data, cell cycle-regulatory genes, CCNE1 and CDKN2B that were induced exclusively by CPDs were selected for further investigation. Following UVB irradiation, expression of these genes increased significantly at both mRNA and protein levels, but not in cells transfected with CPD-photolyase Ψ-mRNA and exposed to photoreactivating light. Treatment of cells with inhibitors of c-Jun N-terminal kinase (JNK) blocked the UVB-dependent upregulation of both genes suggesting a role for JNK in relaying the signal of UVB-induced CPDs into transcriptional responses. Thus, photolyase mRNA-based experimental platform demonstrates CPD-dependent and -independent events of UVB-induced cellular responses, and, as such, has the potential to identify novel molecular targets for treatment of UVB-mediated skin diseases.

Differential p16/INK4A cyclin-dependent kinase inhibitor expression correlates with chemotherapy efficacy in a cohort of 88 malignant pleural mesothelioma patients

Background:

Malignant pleural mesothelioma (MPM) is a rare and essentially incurable malignancy most often linked with occupational exposure to asbestos fibres. In common with other malignancies, the development and progression of MPM is associated with extensive dysregulation of cell cycle checkpoint proteins that modulate cell proliferation, apoptosis, DNA repair and senescence.

Methods:

The expression of cyclin-dependent kinase inhibitor p16/INK4A was evaluated by immunohistochemistry using tumour biopsy specimens from 88 MPM cases and a semi-quantitative score for p16/INK4A expression was obtained. Post-diagnosis survival and the survival benefit of chemotherapeutic intervention was correlated with p16/INK4A expression.

Results:

A low, intermediate and high score for p16/INK4A expression was observed for 45 (51.1%), 28 (31.8%) and 15 (17.1%) of the MPM cases, respectively. Those cases with intermediate or high p16/INK4A tumour expression had a significantly better post-diagnosis survival than those cases whose tumours lost p16 expression (log-rank P<0.001). Those patients with sustained p16/INK4A expression who received chemotherapy also had a better survival than those treated patients whose tumours had lost p16/INK4A expression (log-rank P<0.001).

Conclusions:

Sustained p16/INK4A expression predicts better post-diagnosis survival in MPM and also better survival following chemotherapeutic intervention.

An updated overview of HPV-associated head and neck carcinomas

Human papilloma virus (HPV)-associated head and neck carcinoma is quite heterogeneous and most of the tumors arise in the oral cavity, oropharynx, hypopharynx and larynx. HPV was just recently recognized as an emerging risk factor for oropharyngeal squamous cell carcinoma (OSCC). HPV(+) tumors represent 5-20% of all head and neck squamous-cell carcinomas (HNSCCs) and 40-90% of those arising from the oropharynx, with widely variable rates depending on the geographic area, population, relative prevalence of environment-related SCC and detection assay. Different carcinogenic mechanisms are most likely implicated in cervical and oropharyngeal carcinogenesis. The most certain carcinogenic genotype for the head and neck region and the most common high-risk HPV genotype, HPV-16, is frequently detected in OSCC. A combination of p16INK4A expression and molecular detection of HPV DNA is the gold standard for the viral identification in tissue and exfoliated cell samples. Differences in the biology of HPV(+) and HPV(-) OSCC may have implications for the management of patients. New immunotherapy drugs based on the release of the co-inhibitory receptors, cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed-death 1 (PD-1) have currently emerged. The goal of therapeutic cancer vaccination is inculcation of a persistent, tumor antigen-specific T cell response which kills tumor cells. The efficacy of the current HPV vaccines, Cervarix and Gardasil, in preventing HPV-related HNSCC is at present unknown. Treatment de-escalation is recommended as the current management of HPV-induced HNSCCs.

P14ARF deficiency and its correlation with overexpression of p53/MDM2 in sporadic vestibular schwannomas

Recent studies have shed considerable light into schwannomas. To date, only merlin has been identified as a hallmark or pathogenesis of both sporadic and NF2-related schwannomas. Here, we show, by immunoblot and immunohistochemical analyses of 58 sporadic vestibular schwannomas, that upregulation of p53 was observed in 90 % of tumors examined. No p53 mutations were found in 12 % tumors analyzed. Expression of p14ARF was negative in 95 % of tumors, while overexpression of MDM2 was found in all specimens. Aberrant DNA hypermethylation of the p14ARF promoter was observed in three of seven tumors examined (43 %), associated with remarkably decreased mRNA levels. The very high degree of concordance in the aberrations of the p14ARF/MDM2/p53 pathway in this tumor may be considered to be a new player in the pathogenesis of sporadic vestibular schwannomas. Moreover, expression of p21 (waf1) was negative in all tumors, suggesting that the aberration of this pathway is associated with greater attenuation of p21-mediated signals that are critical for growth inhibition. These data are in agreement with the model in RT-4 rat schwannoma cells: i.e., overexpression of ARF was associated with accumulation of p21 expression both at protein and mRNA levels. ShRNA knock-down of p53 expression attenuated p21-mediated increase in cellular arrest in the G1-phase, suggesting that p14ARF regulates p21 protein levels through a p53-dependent pathway. Thus, this study reveals a high degree of concordance in the aberrations of the p14ARF/MDM2/p53 pathway with the development of sporadic vestibular schwannomas.

Aberrant promoter methylation of p15 (INK⁴b) and p16 (INK⁴a) genes may contribute to the pathogenesis of multiple myeloma: a meta-analysis

We carried out the current meta-analysis aiming to comprehensively assess the potential role of p15 (INK4b) and p16 (INK4a) aberrant promoter methylation in the pathogenesis of multiple myeloma (MM). The MEDLINE (1966 ~ 2013), Cochrane Library (Issue 12, 2013), EMBASE (1980 ~ 2013), CINAHL (1982 ~ 2013), Web of Science (1945 ~ 2013), and Chinese Biomedical (CBM) (1982 ~ 2013) databases were searched without language restrictions. Meta-analyses were conducted using Stata software (Version 12.0, Stata Corporation, College Station, TX, USA). Odds ratios (ORs) and their 95 % confidence intervals (95 %CIs) were calculated. Thirteen clinical case-control studies, which enrolled a total of 465 MM patients and 180 healthy subjects, were included in the meta-analysis. The results of our meta-analysis demonstrated that the frequencies of p15 (INK4b) and p16 (INK4a) promoter methylation in cancer samples were significantly higher than in normal samples (p15 (INK4b) : OR = 6.26, 95 %CI = 3.87 ~ 10.12, P < 0.001; p16 (INK4a) : OR = 2.26, 95 %CI = 1.22 ~ 4.20, P < 0.001). Ethnicity-stratified analysis showed that the aberrant methylation of p15 (INK4b) was significantly related with the risk of MM among both Caucasians and Asians (all P < 0.05). Furthermore, our results also illustrated a strong positive correlation between p16 (INK4a) promoter methylation and the pathogenesis of MM among Asians (OR = 5.17, 95 %CI = 3.45 ~ 7.74, P < 0.001), but not among Caucasians (P > 0.05). The current meta-analysis confirms and reinforces existing findings that p15 (INK4b) and p16 (INK4a) promoter methylation may be closely implicated in the pathogenesis of MM.

Perioral lesions and dermatoses

The purpose of this article is to review the common neoplasms, infections, and inflammatory dermatoses that may present around or near the mouth. Dental professionals are well positioned to evaluate perioral skin conditions, further contributing to patients' general health. This article includes a review of seborrheic keratosis, warts, actinic keratoses, actinic cheilitis, and squamous cell carcinoma, among several other perioral cutaneous lesions.

Actinic keratosis: rationale and management

Actinic keratoses (AKs) are common skin lesions heralding an increased risk of developing squamous cell carcinoma (SCC) and other skin malignancies, arising principally due to excessive ultraviolet (UV) exposure. They are predominantly found in fair-skinned individuals, and increasingly, are a problem of the immunosuppressed. AKs may regress spontaneously, remain stable or transform to invasive SCC. The risk of SCC increases for those with more than 5 AKs, and the majority of SCCs arise from AKs. The main mechanisms of AK formation are inflammation, oxidative stress, immunosuppression, impaired apoptosis, mutagenesis, dysregulation of cell growth and proliferation, and tissue remodeling. Human papilloma virus has also been implicated in the formation of some AKs. Understanding these mechanisms guides the rationale behind the current available treatments for AKs. One of the main principles underpinning the management of AKs is that of field cancerization. Wide areas of skin are exposed to increasing amounts of UV light and other environmental insults as we age. This is especially true for the head, neck and forearms. These insults do not target only the skin where individual lesions develop, but also large areas where crops of AKs may appear. The skin between lesions is exposed to the same insults and is likely to contain as-yet undetectable preclinical lesions or areas of dysplastic cells. The whole affected area is known as the ‘field’. Management is therefore divided into lesion-directed and field-directed therapies. Current therapies include lesion-directed cryotherapy and/or excision, and topical field-directed creams: 5-fluorouracil, imiquimod, diclofenac, photodynamic therapy and ingenol mebutate. Combining lesion- and field-directed therapies has yielded good results and several novel therapies are under investigation. Treatment is variable and tailored to the individual making a gold standard management algorithm difficult to design. This literature review article aims to describe the rationale behind the best available therapies for AKs in light of current understanding of pathophysiology and epidemiology. A PubMed and MEDLINE search of literature was performed between January 1, 2000 and September 18, 2013. Where appropriate, articles published prior to this have been referenced. This is not a systematic review or meta-analysis, but aims to highlight the most up to date understanding of AK disease and its management.

Clinical findings using ingenol mebutate gel to treat actinic keratoses

Actinic keratosis (AK) is a common ultraviolet light-induced skin lesion found on sun-exposed skin areas generally in older, fair-skinned people. It is part of a disease continuum observed in photodamaged skin that may lead to invasive squamous cell carcinoma. The presence of AK is associated with an increased risk of all skin cancers, as it is visible evidence of the carcinogenic effects of cumulative ultraviolet exposure. AKs are treated with lesion- and field-directed methods. Field-directed methods treat both the visible and subclinical lesions present in photodamaged skin, but treatment regimens are often lengthy and associated with poor tolerability because of vigorous local inflammatory reactions. Ingenol mebutate gel was recently approved by the Food and Drug Administration for topical treatment of AK. It induces cell death preferentially in transformed keratinocytes and promotes an inflammatory response that kills remaining tumor cells. In human studies, ingenol mebutate achieved high clearance rates of AK on the trunk or extremities and face or scalp after once-daily application for 2 or 3 consecutive daily treatments, when measured by complete or partial clearance of lesions. The localized inflammatory skin responses were generally mild to moderate and resolved in approximately 2 weeks on the face or scalp and 4 weeks on the trunk or extremities.

Pathobiology of actinic keratosis: ultraviolet-dependent keratinocyte proliferation

Actinic keratoses are proliferations of transformed neoplastic keratinocytes in the epidermis that are the result of cumulative ultraviolet (UV) radiation from sun exposure. They are commonly found on sites of sun-exposed skin such as the face, balding scalp, and back of the hand. Although UV exposure does exert certain beneficial effects on the skin, excessive exposure to UV radiation induces multiple cascades of molecular signaling events at the cellular level that produce inflammation, immunosuppression, failure of apoptosis, and aberrant differentiation. Cumulatively, these actions result in mutagenesis and, ultimately, carcinogenesis. This article provides a brief overview of the key mediators that are implicated in the pathobiology of actinic keratosis. Three evolutionary possibilities exist for these keratoses in the absence of treatment: (1) spontaneous remission, which can be common; (2) remaining stable, without further progression; or (3) transformation to invasive squamous cell carcinoma, which may metastasize. Because the effects of UV radiation on the skin are complex, it is not yet fully clear how all of the mediators of actinic keratosis progression are interrelated. Nonetheless, some represent potential therapeutic targets, because it is clear that directing therapy to the effects of UV radiation at a number of different levels could interrupt and possibly reverse the mechanisms leading to malignant transformation.

Genetic alterations of RD(INK4/ARF) enhancer in human cancer cells

Recent identification of an enhancer element, RD(INK4/ARF) (RD), in the prominent INK4/ARF locus provides a novel mechanism to simultaneously regulate the transcription of p15(INK4B) (p15), p14(ARF) , and p16(INK4A) (p16) tumor suppressor genes. While genetic inactivation of p15, p14(ARF) , and p16 in human tumors has been extensively studied, little is known about genetic alterations of RD and its impact on p15, p14(ARF) , and p16 in human cancer. The purpose of this study was to investigate the potential existence of genetic alterations of RD in human cancer cells. DNAs extracted from 17 different cancer cell lines and 31 primary pheochromocytoma tumors were analyzed for deletion and mutation of RD using real-time PCR and direct DNA sequencing. We found that RD was deleted in human cancer cell lines and pheochromocytoma tumors at frequencies of 41.2% (7/17) and 13.0% (4/31), respectively. While some of these RD deletion events occurred along with deletions of the entire INK4/ARF locus, other RD deletion events were independent of genetic alterations in p15, p14(ARF) , and p16. Furthermore, the status of RD was poorly associated with the expression of p15, p14(ARF) , and p16 in tested cancer cell lines and tumors. This study demonstrates for the first time that deletion of the RD enhancer is a prevalent event in human cancer cells. Its implication in carcinogenesis remains to be further explored.

New developments in the treatment of actinic keratosis: focus on ingenol mebutate gel

Actinic keratosis is a common disease in older, fair-skinned people, and is a consequence of cumulative ultraviolet exposure. It is part of a disease continuum in photodamaged skin that may lead to invasive squamous cell carcinoma. Treatment options frequently used include cryosurgery and topical pharmacologic agents, which are examples of lesion-directed and field-directed strategies. Ingenol mebutate gel was recently approved by the US Food and Drug Administration for topical treatment of actinic keratosis. While the mechanism of action of ingenol mebutate is not fully understood, in vitro and in vivo studies using tumor models indicate it has multiple mechanisms. Ingenol mebutate directly induces cell death by mitochondrial swelling and loss of cell membrane integrity preferentially in transformed keratinocytes. It promotes an inflammatory response characterized by infiltration of neutrophils and other immunocompetent cells that kills remaining tumor cells. The ability of ingenol mebutate to eliminate mutant p53 patches in ultraviolet-irradiated mouse skin suggests that it may have the potential to treat chronically ultraviolet-damaged skin. In human studies, ingenol mebutate achieved high clearance of actinic keratosis on the head and body after 2–3 consecutive daily treatments when measured by complete or partial clearance of lesions. Localized inflammatory skin responses were generally mild to moderate and resolved in less than a month.

Enhancement of cisplatin cytotoxicity by benzyl isothiocyanate in HL-60 cells

Cis-diamminedichloroplatinum (II) (cisplatin) is one of the most widely used chemotherapeutic drugs, but its effectiveness is limited by tumor cell resistance and the severe side effects it causes. One strategy for overcoming this problem is the concomitant use of natural dietary compounds as therapeutic agents. Benzyl isothiocyanate (BITC) is a promising chemopreventive agent found in cruciferous vegetables and papaya fruits. The aim of this study was to investigate the effects of BITC on cisplatin-induced cytotoxicity in human promyelocytic leukemia cells and normal human lymphocytes. The combined treatment of HL-60 cells with BITC followed by cisplatin (BITC/cisplatin) caused a significant decrease in cell viability. BITC also increased apoptotic cell death compared to cisplatin treatment alone. In normal human lymphocytes, BITC did not enhance the cytotoxic effects of cisplatin. Cellular exposure to BITC/cisplatin increased reactive oxygen species (ROS) generation but decreased the total glutathione (GSH) level in HL-60 cells. Pretreatment of HL-60 cells with N-acetylcysteine or glutathione monoethyl ester effectively decreased BITC/cisplatin-induced cell death. The addition of the extracellular signal-regulated kinase (ERK) inhibitor PD98059 abolished BITC/cisplatin-induced apoptosis. Taken together, our results suggest that BITC enhances cisplatin-induced cytotoxicity through the generation of ROS, depletion of GSH, and ERK signaling in HL-60 cells.

p16INK⁴a and p14ARF mRNA expression in Pap smears is age-related

Expression of high-risk HPV oncogenes results in a strong overexpression of cellular protein p16(INK4a). Immunohistochemical staining for p16(INK4a) is widely used as diagnostic marker. However, p16(INK4a) upregulation was also described as a biomarker of age. Here we analyzed p16(INK4a) expression in cervical smears to investigate if patient age may influence p16(INK4a)-based cervical cancer diagnosis. p14(ARF) was analyzed as a related supportive biomarker. Cervical scrapes were taken and stored in RNAlater. Total RNA was extracted, and cDNA was analyzed for expression of p16(INK4a) and p14(ARF) relative to β-actin, by real-time reverse transcriptase PCR SYBR-Green I assays. Patient-derived smears referred as HSIL (n=45) had 6.27-fold higher p16(INK4a) mRNA expression than smears of cytologically normal and HPV-negative persons (n=48). Expression of p14(ARF) was 4.87-fold higher. When women with normal diagnoses were stratified for age, a significantly enhanced p16(INK4a) (2.88-fold) and p14(ARF) (1.9-fold) expression was observed as a consequence of ageing. A significant age-dependent upregulation was also observed in older HSIL patients (2.54-fold). Our study revealed significantly enhanced expression of p16(INK4a)/p14(ARF) mRNA in cervical scrapes referred to as HSIL compared with normal women. An age-dependent bias has to be considered when quantifying these tumor suppressor genes, with respect to cervical cancer development.

Expression of TWEAK in normal human skin, dermatitis and epidermal neoplasms: association with proliferation and differentiation of keratinocytes

BACKGROUND

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) has been implicated in the pathogenesis of various inflammatory pathologies and cancer. We aimed to investigate its expression in normal human skin, inflammatory skin diseases and epidermal neoplasms.

METHODS

Immunohistochemistry for TWEAK was performed in samples of healthy skin, plaque psoriasis, lichen planus, prurigo nodularis, discoid lupus erythematosus, lichen sclerosus, seborrheic keratosis, common warts, actinic keratosis, Bowen's disease, keratoacanthoma and basal and squamous cell carcinoma. Double immunofluorescence was used to investigate co-localization of TWEAK with cytokeratin-10 and proliferating cell nuclear antigen (PCNA).

RESULTS

TWEAK was robustly expressed in the epidermis of healthy skin and decreased in inflammatory conditions, both in the context of epidermal hyperplasia and atrophy. Decreased TWEAK immunoreactivity was regularly observed in common warts, actinic keratosis and Bowen's disease, particularly in areas of marked proliferation as evidenced by PCNA-positive nuclei. In squamous cell carcinoma, expression of TWEAK ranged from strong to completely absent, and it mostly corresponded with the expression of cytokeratin-10. TWEAK was absent in keratoacanthoma and basal cell carcinoma.

CONCLUSIONS

TWEAK is a constitutively expressed epidermal protein whose downregulation might be an early indicator of disturbed differentiation or pathologic proliferation of keratinocytes that accompany inflammatory and neoplastic skin diseases.

Genetic variability of the distal promoter of the ST2 gene is associated with angiographic severity of coronary artery disease

Genetic polymorphy of the distal promoter region of the ST2 gene influences transcriptional activity and susceptibility to atopic dermatitis and asthma. Based on the inflammatory background of atherosclerosis we hypothesized that ST2 distal promoter genetic polymorphy could also affect susceptibility to coronary artery disease (CAD). To test our hypothesis we performed direct sequencing of a 825 bp locus of the distal promoter -with previously reported significant polymorphy in 63 angiographically diagnosed CAD patients and 63 age and sex matched controls with negative coronary angiography. We identified 13 polymorphisms spanning this region two of which (-27307 T/A and -27614 C/A) had allele frequencies greater than 0.05. We further genotyped 111 subjects by applying allele-specific real-time PCR for the -27307 T/A and 27614 C/A polymorphisms, thereby increasing our sample to 129 CAD patients and 108 age- and sex-matched controls. We identified no phenotype-genotype interactions between cases and controls. However, among case subjects the severity of CAD expressed as a mean number of diseased vessels was greater in -27307 A allele carriers and either allele carriers (-27614 A or -27307 A) than in non-carriers (2.56 ± 0.73 vs. 1.83 ± 0.84, adjusted P = 0.027; 2.47 ± 0.74 vs. 1.8 ± 0.83, adjusted P = 0.023). Additionally, either allele carriers (-27614 A or -27307 A) were significantly more common in the multi-vessel disease group (n = 54) than in the single-vessel disease group (n = 75). In conclusion, we reported two new polymorphisms in the distal promoter region of the ST2 gene that possibly influence susceptibility to severe CAD. The functional impact of these polymorphisms remains to be determined.

Comparative studies on the genotoxicity and cytotoxicity of polymeric gene carriers polyethylenimine (PEI) and polyamidoamine (PAMAM) dendrimer in Jurkat T-cells

A safe alternative to the viral system used in gene therapy is a nonviral gene delivery system. Although polyethylenimine (PEI) and polyamidoamine (PAMAM) dendrimer are among the most promising gene-carrier candidates for efficient nonviral gene delivery, safety concerns regarding their toxicity remain. The aim of this study was to scrutinize the underlying mechanism of the cytotoxicity and genotoxicity of PEI (25 kDa) and PAMAM (G4). To our knowledge, this is the first study to explore the genotoxic effect of polymeric gene carriers. To evaluate cell death by PEI and PAMAM, we performed propidium-iodide staining and lactate-dehydrogenase release assays. The genotoxicity of the polymers was measured by comet assay and cytokinesis-block micronucleus assay. PEI- and PAMAM-treated groups induced both necrotic and apoptotic cell death. In the comet assay and micronuclei formation, significant increases in DNA damage were observed in both treatments. We conclude that PEI and PAMAM dendrimer can induce not only a relatively weak apoptotic and a strong necrotic effect, but also a moderate genotoxic effect.

Genomic instability in human actinic keratosis and squamous cell carcinoma

OBJECTIVE

To compare the repetitive DNA patterns of human actinic keratoses and squamous cell carcinomas to determine the genetic alterations that are associated with malignant transformation.

INTRODUCTION

Cancer cells are prone to genomic instability, which is often due to DNA polymerase slippage during the replication of repetitive DNA and to mutations in the DNA repair genes. The progression of benign actinic keratoses to malignant squamous cell carcinomas has been proposed by several authors.

MATERIAL AND METHODS

Eight actinic keratoses and 24 squamous cell carcinomas (SCC), which were pair-matched to adjacent skin tissues and/or leucocytes, were studied. The presence of microsatellite instability (MSI) and the loss of heterozygosity (LOH) in chromosomes 6 and 9 were investigated using nine PCR primer pairs. Random Amplified Polymorphic DNA patterns were also evaluated using eight primers.

RESULTS

MSI was detected in two (D6S251, D9S50) of the eight actinic keratosis patients. Among the 8 patients who had squamous cell carcinoma-I and provided informative results, a single patient exhibited two LOH (D6S251, D9S287) and two instances of MSI (D9S180, D9S280). Two LOH and one example of MSI (D6S251) were detected in three out of the 10 patients with squamous cell carcinoma-II. Among the four patients with squamous cell carcinoma-III, one patient displayed three MSIs (D6S251, D6S252, and D9S180) and another patient exhibited an MSI (D9S280). The altered random amplified polymorphic DNA ranged from 70% actinic keratoses, 76% squamous cell carcinoma-I, and 90% squamous cell carcinoma-II, to 100% squamous cell carcinoma-III.

DISCUSSION

The increased levels of alterations in the microsatellites, particularly in D6S251, and the random amplified polymorphic DNA fingerprints were statistically significant in squamous cell carcinomas, compared with actinic keratoses.

CONCLUSION

The overall alterations that were observed in the repetitive DNA of actinic keratoses and squamous cell carcinomas indicate the presence of a spectrum of malignant progression.

Expression of differential genes involved in the maintenance of water balance in human skin by Piptadenia colubrina extract

BACKGROUND

Hydration and integrity of the stratum corneum (SC) is an important determinant of skin appearance, metabolism, mechanical properties, and barrier function. The presence of aquaglyceroporins and envelope proteins are crucial to provide greater corneocyte cohesion to keep water and other moisturizers in the skin.

AIMS

In this study, we evaluated the ability of Piptadenia colubrina, a plant native of South American rain forests, in the expression of genes involved in skin capacitance and SC integrity.

METHODS

The expression of genes for aquaporin-3 (AQP3), loricrin, involucrin (INV), and filaggrin (FLG) was measured by real-time PCR, using an in vitro model of human keratinocytes incubated with concentrations of 2.5, 5, 10, and 20 mg/mL of a hydroglycolic extract of P. colubrina (HEPC). The amount of AQP3 protein was also tested by immunohistochemistry in human skin explants. Clinical trials were conducted to evaluate the effects of a gel-cream containing HEPC on the glycerol index and skin capacitance.

RESULTS

Hydroglycolic extract of P. colubrina increased both the expression and immunoreactivity of AQP3 in cultured keratinocytes and human skin explants. The gene induction to envelope proteins FLG and INV was also observed after cell incubation with HEPC. Skin capacitance was significantly improved in human volunteers under treatment with HEPC-containing cream.

CONCLUSIONS

The extract of P. colubrina promotes cellular hydration and induces gene expression of envelope proteins providing greater corneocyte cohesion to keep water and other moisturizers in the skin and an appropriate epidermal adhesion. The in vitro findings were clinically confirmed and encourage the clinical use of this compound in skin care products.

A genetic variant of Aurora kinase A promotes genomic instability leading to highly malignant skin tumors

Aurora kinase A (Aurora-A) belongs to a highly conserved family of mitotis-regulating serine/threonine kinases implicated in epithelial cancers. Initially we examined Aurora-A expression levels at different stages of human skin cancer. Nuclear Aurora-A was detected in benign lesions and became more diffused but broadly expressed in well and poorly differentiated squamous cell carcinomas (SCC), indicating that Aurora-A deregulation may contribute to SCC development. To mimic the overexpression of Aurora-A observed in human skin cancers, we established a gene-switch mouse model in which the human variant of Aurora-A (Phe31Ile) was expressed in the epidermis upon topical application of the inducer RU486 (Aurora-AGS). Overexpression of Aurora-A alone or in combination with the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA), did not result in SCC formation in Aurora-AGS mice. Moreover, Aurora-A overexpression in naive keratinocytes resulted in spindle defects in vitro and marked cell death in vivo, suggesting that the failure of Aurora-A to initiate tumorigenesis was due to induction of catastrophic cell death. However, Aurora-A overexpression combined with exposure to TPA and the mutagen 7,12-dimethylbenz(a)anthracene accelerated SCC development with greater metastatic activity than control mice, indicating that Aurora-A cannot initiate skin carcinogenesis but rather promotes the malignant conversion of skin papillomas. Further characterization of SCCs revealed centrosome amplification and genomic alterations by array CGH analysis, indicating that Aurora-A overexpression induces a high level of genomic instability that favors the development of aggressive and metastatic tumors. Our findings strongly implicate Aurora-A overexpression in the malignant progression of skin tumors and suggest that Aurora-A may be an important therapeutic target.