Context: Squamous cell carcinoma (SCC) is the second most common skin cancer. Ultraviolet radiation (UVR) exposure, its most important risk factor, has mostly been investigated in cross-sectional study designs. This study presents a comprehensive and longitudinal examination of determinants of SCC, including photoageing. Objective: To examine the determinants of SCC and its precursor condition of photoageing. Above all, the objective was to investigate the interplay of phenotypic traits; occupation and leisure-time sun exposure patterns; and personal exposures, in particular, tobacco smoking and life course sun exposure, upon the risk of SCC and photoageing. Setting and Design: This investigation formed part of a large community-based, long-term cohort study of skin cancer. The Nambour Skin Cancer Study (forthwith, the Nambour Study) began in 1986 and concluded in 2007. In 1986 a random sample of 2095 people (aged 20-69 years) from Nambour, Queensland participated in a skin cancer survey. In 1992, a 5 year field trial to assess the preventive actions of sunscreen and beta-carotene was initiated (n=1621). Regular full skin examinations were conducted to determine the presence of skin cancer and actinic skin damage. In 1994, participants detailed their life course sun exposure (n=1290). After the trial ended in 1996, participants continued to complete regular questionnaires and ascertainment of skin cancers continued to 2007. Participants: The participants were 1339 unselected adults aged 25 to 75 years who had taken part in the Nambour Study in 1992 and consented to the follow-up study. Methods: Life course sun exposure hours were estimated from questionnaires and the approximate UVR exposure for Nambour (latitude 26S) was determined. Descriptive analyses examined patterns of exposure within the population. Factors influencing the severity of photoageing were also investigated. Informed by these analyses, relative risks were calculated for determinants of SCC and population attributable risk percentage (PAR%) for key modifiable risk factors. To investigate tobacco smoking as a risk factor for SCC, systematic review and meta-analysis were performed. Exposure measures: Pigmentary phenotype, estimated UVR exposure, tobacco smoking, sun-related behaviours, e.g. sunscreen use. Outcome measures: Incident and histologically proven SCC of the skin from 1992 to 2007 was the main outcome assessed. Photoageing, assessed clinically and micro-topographically (Beagley and Gibson scale), was an intermediate outcome measure and an objective measure of cumulative sun exposure in the final SCC analysis. Results: Examination of self-reported UVR revealed mean annual exposures were highest in early life and older adulthood (older than 60 years.) Women reported spending less time in the sun than men in all stages of life (p<0.05) and the more sun-sensitive the person’s skin type, the less sun exposure was reported at each life stage. The role of tobacco smoking in cutaneous SCC was reviewed in the published literature and a small positive association was noted in the meta-analysis. However, few studies had adjusted, or adjusted adequately, for sun exposure. Within the Nambour Study, with adjustment for age, sex, skin phenotype, lifetime sun exposure, current and former smoking had no association with SCC (RR 1.2, 95%CI 0.7, 2.0 and RR 1.1, 95%CI 0.8, 1.5, respectively compared with lifelong non-smokers). In this study population, with moderate to severe photoageing at study baseline, increasing age, male sex, a sun-sensitive phenotype were found to increase the odds of more severe actinic damage (p<0.05). High or very high UVR exposure in adulthood predicted a greater severity (OR 2.2, 95%CI 1.3, 4.0). Finally, the determinants of SCC were examined. Increasing age (4% increase per year of life, 95%CI 3% to 5%), male sex (RR 1.4, 95%CI 1.1, 1.9) and fair skin (RR 4.7 95%CI 2.0, 11.4) were associated with SCC. Having light eye colour and fair or red hair also significantly increased SCC risk. Recalled life course sun exposure overall was not found to be associated with SCC. Signs of actinic damage at baseline were, however, very strongly associated with SCC. Recent sun exposure, defined as that reported in the period (1-2 years) before the occurrence of SCC or for those unaffected at the end of the study, was also examined. A strong positive association was found between high recent exposure and SCC (RR 2.1, 95%CI 1.3, 3.3). PAR% estimates of prominent modifiable risk factors for SCC suggested considerable potential for reduction in incidence for at-risk populations if recent sun exposure were reduced. Conclusions: Subjective measures of solar UVR exposure and objective measures of photoageing varied according to personal and phenotypic factors. The interplay between risk factors observed here highlight the need to control for confounding in investigating solar factors as causes of skin cancer. Although SCC occurred on the background of high cumulative UVR exposure, which was best determined with objective rather than recalled measures, recent UVR exposure was also important. Self-reported recent exposure being less subject to recall bias than reported life course exposure may have partly influenced this, but the impact of UVR acting as a tumour initiator and promoter is also likely to explain the relation of SCC to sun exposure in the recent past.

Throughout gestation, the blood vessel network of the placenta is formed sequentially by processes known as vasculogenesis and angiogenesis, which together meet the needs of the growing fetus. Normal placental angiogenesis is critical to support adequate fetal growth and assure the health of the offspring. Proper angiogenesis requires precise regulation of expression of agents that modulate this process; otherwise, pathologies of pregnancy such as preeclampsia may occur. The placenta is composed of different layers of tissue, including the lamellar (LZ), junctional, and glandular zones, each with a vascular morphology attuned to its function. We hypothesized that higher expression of pro-angiogenic factors is associated with increased morphological metrics in the LZ, the major vascularized zone. Thus, we aimed to characterize the major changes in morphology and vascular development in the placenta throughout pregnancy in cats, alongside a compressive analysis of the expression of major angiogenic factors and their receptors in the placenta, with an emphasis on the identification and interaction of different isoforms of the VEGF family. Microscopic analysis of tissue specimens from different stages of pregnancy revealed increased thickness of the LZ, especially during early to mid-gestation, at which time the tissue is composed of abundant materno-fetal interdigitations that appears rich in capillaries. VEGF proteins were detected in placental tissue in both fetal and maternal cells of the placenta, suggesting stimulatory interactions between different cell types to promote growth and angiogenesis. Gene expression analysis of placenta revealed upregulation of the pro-angiogenic factor VEGF-A in mid-pregnancy, followed by a steady decline toward term, consistent with morphologic changes in the LZ. In contrast, another pro-angiogenic factor, PlGF, showed a marked increase toward term; Flt-1, which acts as a receptor or reservoir for PLGF and VEGF A, was also upregulated at late pregnancy. Increased ratios of PLGF:VEGF-A may contribute to LZ proliferation in the last trimester. These findings are consistent with the creation of a proangiogenic placental state during gestation. Overall, we expect that this research will help elucidate mechanisms of placental vascularization, which can be applied to the design of improved strategies to treat vascular complications of pregnancy. Lastly, we applied the tools developed for placental studies to investigate pathologic angiogenesis in cutaneous squamous cell carcinoma (CSCC), a common skin cancer with major economic and medical impacts in humans and veterinary species. The creation of a new blood supply is essential for growth and metastasis of many tumor types. The goal of this study was to measure expression of variants of proteins that stimulate angiogenesis or transmit an angiogenic stimulus in feline CSCC. The results were mixed, with differences detected in expression of some regulatory agents and, for others, unexpectedly lower expression in CSSC compared to controls. Interestingly, the expression of VEGF-A relative to the protein that transmits its signal (KDR) was elevated in CSCC, suggestive of an altered signaling relationship. This finding supports our hypothesis and is consistent with human SCC studies. Our results encourage further studies on angiogenic factor variants in feline CSCC. / PHD

No description available.

INTRODUÇÃO: A epidermodisplasia verruciforme (EV) é uma rara genodermatose, associada ao beta-papilomavírus humano (Beta-HPV) e alto risco de desenvolvimento de câncer de pele. As claudinas são proteínas transmembranas expressas nos diversos epitélios e podem se alterar na carcinogênese. Para melhor compreensão do papel do Beta-HPV na carcinogênese cutânea, realizou-se um estudo da expressão das claudinas nos pacientes com e sem EV. MÉTODOS: Um painel de anticorpos anti-claudina -1, -2, -3, -4, -5, -7 e -11 foi empregado para analisar a expressão dessa proteína em 108 amostras de pele normal, 39 verrugas planas e 174 carcinomas espinocelulares cutâneo (CEC), obtidas de 33 pacientes com epidermodisplasia verruciforme (EV) e 112 indivíduos saudáveis (não EV- NEV). As amostras de CEC foram organizadas em 4 microarranjos teciduais. A análise estatística foi realizada por regressão logística para verificar as alterações do perfil de claudinas na carcinogênese e sua relação com idade, sexo e fotoexposição crônica nos doentes com EV e o grupo NEV. RESULTADOS: A expressão focal da claudina-1 apresentou associação com o CEC (p < 0,001) e a expressão não difusa (focal ou negativa) da claudina-2 esteve associado a verruga plana (p < 0,001), nos grupos EV e NEV. A expressão focal da claudina-3 apresentou associação com o CEC (p < 0,001), bem como a imunomarcação nuclear da claudina-3 (p < 0,001), em ambos os grupos. Adicionalmente, a chance da expressão nuclear da claudina-3 foi 53% menor nas áreas não fotoexpostas. A claudina-5 apresentou maiores porcentagens de expressão focal na pele normal, de expressão difusa no CEC e na verruga plana EV, e de expressão negativa na verruga plana NEV. O grupo EV apresentou menor chance de expressão focal e negativa (p < 0,001). Além disso, a negatividade da claudina-5 esteve associada a verruga plana (p < 0,001) e menor média de idade (p < 0,001). As claudinas -4, -7 e -11 apresentaram expressão difusa em quase todas as amostras estudadas, nos grupos EV e NEV. CONCLUSÕES: Verificou-se aumento progressivo da claudina-5 na carcinogênse cutânea e esse processo apresentou relação com a EV. Redução da expressão das claudinas -1 e -3 foi observada nos carcinomas cutâneos, e da claudina-2 nas verrugas planas, no entanto, não puderam ser relacionadas à infecção pelo beta-HPV. Idade e fotoexposição crônica foram fatores que influenciaram a expressão da claudina-5 e a expressão nuclear da claudina-3, respectivamente / BACKGROUND: Epidermodysplasia verruciformis (EV) is a rare genodermatosis, related to human beta-papillomavirus (Beta-HPV), with high risk for developing skin cancer. Claudins are transmembrane proteins expressed in epithelia and may be altered on carcinogenesis. Toward better understanding the role of Beta-HPV in cutaneous carcinogenesis, claudin expression study was performed in lesions of patients with and without EV. METHODS: A panel of anti-claudin antibodies was assembled to analyze claudins -1, -2, -3, -4, -5, -7 and -11 expression, by immunohistochemistry technique, in samples of 108 normal skin, 39 flat warts and 174 cutaneous squamous cell carcinomas (SCC), obtained from 33 patients with EV and 112 individuals without EV (not-EV - NEV). The SCC samples were organized in tissue microarrays. Statistical analysis was performed by logistic regression, aiming to verify changes in claudin profile in carcinogenesis and its relationship with age, sex and chronic sun exposure area, in patients with and without EV. RESULTS: Claudin-1 focal expression was associated with SCC (p < 0.001) and claudin-2 focal or negative expression with flat wart (p < 0.001), in EV and NEV groups. Claudin-3 focal expression was related with SCC (p < 0.001), as well as the nuclear immunostaining of claudin-3 (p < 0.001), in both groups. Additionally, chance of claudin-3 nuclear expression was 53% lower in not sun exposed areas. For claudin-5, focal expression was more common in normal skin, diffuse expression in SCC annd EV flat wart, and negative expression in NEV flat wart. The EV group showed lower chance of focal and negative expression (p < 0.001). In addition, the negativity of claudin-5 expression was associated with flat wart (p < 0.001) and lower mean age (p < 0.001). Claudins -4, -7 and -11 showed, in both groups, diffuse expression in almost all studied samples. CONCLUSIONS: Claudin-5 increasing expression was observed in cutaneous carcinogenesis and this process showed association with EV. Claudin-1 and -3 down expression were observed in cutaneous carcinomas, and claudin-2 in flat warts, however, they could not be related with Beta-HPV infection. Age and chronic sun exposure area were factors that influenced claudin-5 and claudin-3 nuclear expression, respectively

A terapia fotodinâmica (TFD) é uma modalidade clínica para tratar uma variedade de neoplasias, doenças de pele e representa um promissor tratamento estético. O presente trabalho avaliou os aspectos histopatológicos e moleculares do tratamento pela TFD mediada por azul de metileno (TFD-AM) no modelo experimental in vivo do Carcinoma Espinocelular Cutâneo (CEC) e na pele sadia de camundongos Swiss. O protocolo da TFD foi de uma única sessão, com aplicação da solução de AM a 1% seguido por irradiação com laser diodo na dose total de 24 J/cm2 nos tecidos tumorais e sadios. Os animais foram sacrificados em dois períodos, 24 horas e 15 dias após TFD. Alterações morfológicas foram pouco marcantes nos tecidos tumorais tratados, entretanto, foram mais pronunciadas nos tecidos sadios. Podemos concluir que os efeitos de uma única sessão da TFD mediada pelo AM na dose aplicada não conferiu melhora no tratamento do CEC. Estes resultados motivam novos estudos com ajustes no protocolo para melhorar a eficácia desta terapia. / Photodynamic therapy (PDT) is a clinical method for treating a variety of tumors, skin disorders and represents a promising cosmetic treatment. This study evaluated the histopathological and molecular aspects of the treatment by PDT mediated by methylene blue (PDT-MB) in vivo experimental model of cutaneous squamous cell carcinoma (SCC) and in healthy skin of swiss mice. The PDT protocol was a single session with the application of MB 1% solution followed by irradiation with diode laser at a total dose of 24 J/cm2 in tumor and healthy tissue. The animals were sacrificed at two periods, 24 hours and 15 days after PDT. Morphological changes were less marked in the tumor tissues treated, however, were more pronounced in healthy tissues treated. We can conclude that the effects of a single session of PDT mediated by MB in applied dose conferred no improvement in the treatment of SCC. These results motivate further studies with adjustments in the protocol to improve the effectiveness of this therapy.

Le carcinome épidermoïde cutané (CEC) est l'un des cancers les plus fréquents et il est résistant aux traitements chimiothérapeutiques classiques. De nombreuses études montrent que selon leur phénotype les cellules du microenvironnement inflammatoire peuvent inhiber (cellules Th1/M1) ou favoriser (cellules Th2/M2) le développement tumoral. En fonction des cytokines présentes dans ce microenvironnement, il est possible de reprogrammer les cellules immunitaires et de les rendre moins permissives au développement tumoral. L’onconstatine M (OSM) est une cytokine aux effets pléiotropes, elle peut favoriser la prolifération, l’invasion tumorale des cellules tumorales et induire une polarisation immunitaire Th2/M2. Nous avons montré que l'OSM a des effets pro-inflammatoires au niveau cutané et qu’elle module le phénotype des kératinocytes normaux mais son rôle dans les CEC n’est pas décrit. Nous avons donc étudié l’implication de l'OSM dans le développement des CEC. Nous avons montré que l'OSM était surexprimée dans les CEC humains ainsi que d'autres cytokines comme l'IL-6, l'IL-1β, l'IFNγ suggérant une polarisation Th1/M1 des cellules du microenvironnement. In vitro, l'OSM induit l’activation de voies de signalisation pro-tumorales (STAT3 - ERK) au niveau de kératinocytes murins malins ainsi que leur prolifération et leur migration. La greffe de ces cellules chez la souris entraine le développement de CEC associés à une surexpression d'OSM. Enfin, l’absence d'OSM entraine une diminution du volume tumoral de 30% et à une réduction de la polarisation M2. Collectivement, ces résultats suggèrent un rôle pro-tumoral de l'OSM dans le développement des CEC et le blocage de cette cytokine pourrait constituer une nouvelle alternative thérapeutique. / Cutaneous squamous cell carcinoma (cSCC) is one of the most frequent keratinocyte malignancies worldwide and is chemotherapy resistant. Surgery is the curative treatment but there isn’t any alternative in advanced cSCC. Reprogramming tumor microenvironment and tumor immunosuppressive mechanisms is a new therapeutic approach. Indeed, depending on cytokine expressed in tumor microenvironment, immune cells can inhibit (Th1/M1 cells) or enhance (Th2/M2 cells) tumor development. It was previously showed that Onconstatin M (OSM) had pleiotropic effects on cancer cells. OSM can promote cancer by inducing tumor cells motility, invasiveness or by reprogramming immune cells toward a more permissive phenotype (M2 polarization). Our previous data showed that OSM has proinflammatory effects on skin and modulate normal keratinocyte phenotype both in vitro and in vivo. In this study, we hypothesized that OSM could be involved in cSCC development. We showed that OSM was overexpressed in human cSCC as well as other cytokines such as IL-6, IL-1β, IFNγ whereas IL-4 was decreased, suggesting a Th1/M1 polarization of cSCC microenvironment. In vitro, OSM induced STAT-3 and ERK signalization, modified gene expression, promoted proliferation and migration of malignant keratinocyte PDVC57 cells. PDVC57 cells grafted in skin mice led to cSCC development associated to OSM overexpression by immune infiltrated cells. Finally, we showed that the absence of OSM led to a 30% reduction of tumor size and reduced M2 polarization in tumor microenvironment. Collectively, these results support a pro-tumoral role of OSM in cSCC development and suggest a new therapeutic approach targeting this cytokine.

No description available.

A terapia fotodinâmica (TFD) é uma modalidade clínica para tratar uma variedade de neoplasias, doenças de pele e representa um promissor tratamento estético. O presente trabalho avaliou os aspectos histopatológicos e moleculares do tratamento pela TFD mediada por azul de metileno (TFD-AM) no modelo experimental in vivo do Carcinoma Espinocelular Cutâneo (CEC) e na pele sadia de camundongos Swiss. O protocolo da TFD foi de uma única sessão, com aplicação da solução de AM a 1% seguido por irradiação com laser diodo na dose total de 24 J/cm2 nos tecidos tumorais e sadios. Os animais foram sacrificados em dois períodos, 24 horas e 15 dias após TFD. Alterações morfológicas foram pouco marcantes nos tecidos tumorais tratados, entretanto, foram mais pronunciadas nos tecidos sadios. Podemos concluir que os efeitos de uma única sessão da TFD mediada pelo AM na dose aplicada não conferiu melhora no tratamento do CEC. Estes resultados motivam novos estudos com ajustes no protocolo para melhorar a eficácia desta terapia. / Photodynamic therapy (PDT) is a clinical method for treating a variety of tumors, skin disorders and represents a promising cosmetic treatment. This study evaluated the histopathological and molecular aspects of the treatment by PDT mediated by methylene blue (PDT-MB) in vivo experimental model of cutaneous squamous cell carcinoma (SCC) and in healthy skin of swiss mice. The PDT protocol was a single session with the application of MB 1% solution followed by irradiation with diode laser at a total dose of 24 J/cm2 in tumor and healthy tissue. The animals were sacrificed at two periods, 24 hours and 15 days after PDT. Morphological changes were less marked in the tumor tissues treated, however, were more pronounced in healthy tissues treated. We can conclude that the effects of a single session of PDT mediated by MB in applied dose conferred no improvement in the treatment of SCC. These results motivate further studies with adjustments in the protocol to improve the effectiveness of this therapy.

Les carcinomes spinocellulaires cutanés (cSCCs) sont le deuxième type de cancer par ordre de fréquence et sont responsables de 25% des décès dus aux cancers de la peau. Il est donc essentiel de caractériser les mécanismes responsables de la cancérisation de l'épiderme afin de développer de nouveaux traitements. Dans ce contexte, les miRNAs apparaissent comme des cibles de choix pour le développement de futures thérapies anti-tumorales. Toutefois, leur implication dans la physiopathologie des cSCCs est encore peu documentée. Au cours de cette étude, j’ai identifié, par séquençage à haut débit, 112 miRNAs dont l’expression est altérée au cours du développement tumoral dans un modèle murin de carcinogénèse chimique cutanée. J’ai ensuite focalisé mon attention sur le cluster miR-193b/365a et sur miR-708 dont les niveaux diminuent au cours de la progression tumorale, suggérant des fonctions de suppresseurs de tumeur. En accord avec cette hypothèse, l’expression ectopique de ces miRNAs inhibe la prolifération, la survie et la migration de cellules tumorales, alors que le blocage de leur action par des anti-sens stimule ces fonctions cellulaires dans des kératinocytes normaux. L’association d’approches in silico et d’analyses du transcriptome de cellules de cSCC sur-exprimant ces miRNAs m’a permis d’identifier leurs gènes cibles potentiels. J’ai validé KRAS et MAX comme cibles communes de miR-193b et miR-365a, et montré par l’utilisation de siRNAs que la répression de ces cibles mime les effets de ces miRNAs. Ces résultats suggérent que le ciblage de ces gènes pourrait médier en partie les effets suppresseurs de tumeur de miR-193b et de miR-365a dans les cSCCs. / Cutaneous squamous cell carcinomas (cSCCs) are the second most common cancer and are responsible for up to 25% of all skin cancer deaths. It is therefore essential to characterize the mechanisms responsible for epidermis carcinogenesis to develop new treatments. In this context, miRNAs appear to be prime targets for the development of future anti-tumor therapies. However, their involvement in the pathophysiology of cSCCs is still poorly documented. In this study, I identified using Small RNA sequencing, 112 miRNAs whose expression is altered during tumor development in a mouse model of cutaneous two-stage chemical carcinogenesis. Then, I focused my attention on the miR-193b/365a cluster and on miR-708, that are down-regulated during tumorigenesis, suggesting tumor suppressor functions. Consistent with this hypothesis, the ectopic expression of these miRNAs inhibit the proliferation, survival and migration of tumor cells, while blocking their action with antisense oligonucleotides stimulates these cellular functions in normal keratinocytes. Combining in silico target-prediction approaches and transcriptome analyzes of cSCC cells over-expressing these miRNAs, I identified their potential target genes. I validated KRAS and MAX as direct targets of miR-193b and miR-365a, and I showed that repression of these genes using siRNAs mimics the effects of these miRNAs. These results suggest that targeting these genes might mediate, at least in part, the tumor suppressor action of miR-193b and miR-365a in cSCCs.