LncRNA LINC00483 promotes gastric cancer development through regulating MAPK1 expression by sponging miR-490-3p

BACKGROUND: Previous studies have shown that long noncoding RNA (IncRNA) LINC00483 was aberrantly expressed in human cancers, including gastric cancer. However, the regulatory mechanism of this IncRNA in gastric cancer remains largely unknown. The present study aimed to investigate the effect of LINC00483 on gastric cancer development and explore the potential regulatory network of LINC00483/microRNA (miR)-490-3p/mitogen-activated protein kinase 1 (MAPK1). METHODS: Thirty patients with gastric cancer were recruited for tissues collection. The expression levels of LINC00483, miR-490-3p and MAPK1 were detected by quantitative real-time polymerase chain reaction or western blot. Cell viability, apoptosis, migration and invasion were determined by MTT, flow cytometry, transwell assays and western blot, respectively. The target association between miR-490-3p and LINC00483 or MAPK1 was confirmed by luciferase reporter assay. Xenograft model was established to assess the function of LINC00483 in vivo. RESULTS: LINC00483 and MAPK1 levels were increased in gastric cancer tissues and cells. Knockdown of LINC00483 or MAPK1 inhibited cells viability, migration and invasion but promoted apoptosis in gastric cancer cells. Moreover, MAPK1 overexpression attenuated the effect of LINC00483 knockdown on gastric cancer development. LINC00483 could increase MAPK1 expression by competitively sponging miR-490-3p. miR-490-3p overexpression suppressed gastric cancer development, which was abated by introduction of LINC00483. Besides, inhibition of LINC00483 decreased xenograft tumor growth by regulating miR-490-3p/MAPK1 axis. CONCLUSION: Knockdown of LINC00483 inhibited gastric cancer development in vitro and in vivo by increasing miR- 490-3p and decreasing MAPK1, elucidating a novel mechanism for understanding the development of gastric cancer.

Efeito da infecção por HPV nas vias de sinalização por toll like receptors / Effects of HPV infection on TLR signaling pathway

As oncoproteínas E6 e E7 do Papilomavírus Humano (HPV) estão envolvidas na desregulação do sistema imune inato, provocando alterações na expressão dos receptores do tipo Toll (TLR). Considerando-se a função da via de sinalização iniciada por TLR, haveria uma vantagem para o vírus capaz de manipular a resposta desta via de modo que possa persistir nas células sem ser detectado pelo sistema imune ou ainda modulando essa resposta e criando um ambiente mais propício à manutenção da infecção. No entanto, muitos dos mecanismos que levam à eliminação da infecção ou persistência do HPV ainda são pouco conhecidos. O objetivo principal desse trabalho é investigar o papel das vias de TLR no processo de carcinogênese mediado por HPV. Inicialmente, foi analisada a expressão de genes da via de TLR em linhagens de tumores cervicais e em células expressando as oncoproteínas virais. Foram identificados vários genes diferencialmente expressos entre linhagens de células tumorais e queratinócitos normais, incluindo moléculas adaptadoras da via de TLR e genes associados à via da MAP quinase, ativação de NFkappaB e resposta imune antiviral. Cerca de 90% destes genes foram regulados negativamente. Entre eles, destacamos HMGB1, que apesar de possuir menos RNAm nas células tumorais possui um nível proteico muito maior, além de ter-se mostrado de grande importância para a viabilidade e proliferação das células tumorais, conforme demonstrado através de experimentos de supressão gênica. Em conjunto, os nossos dados indicam que E6 e E7 de HPVs de alto risco inibem proteínas da via de sinalização de TLR

Previous studies have shown that E6 and E7 HPV oncoproteins are involved in innate immune system dysregulation, causing alterations on Toll-like receptors (TLR) expression. Considering TLR pathway function, it would be advantageous for a virus to manipulate the response of this pathway so it can persist in cells without being detected by the immune system or to modulate this response to create a better environment for persistence of infection. However, many of the mechanisms leading to HPV infection clearance or persistence are still unknown and matter of active investigation. We analyzed in cervical cancer cell lines expression of genes from TLR pathway; several were differentially expressed between tumor cells lines and normal keratinocytes, including TLR adaptors molecules and genes associated with MAP kinase pathway, NFkappaB activation and antiviral immune response. About 90% of these genes were down regulated. Among them, we selected HMGB1 for further characterization due to its interference with tumor cell viability and proliferation. Altogether, our data indicate that high risk HPV E6 and E7 can inhibit TLR signaling pathway

Vias de transdução de sinal e polimorfismo de Toll-like Receptors na carcinogenese por HPV / Toll-like Receptors signaling pathway and polymorphism on the HPV carcinogenesis

Seres humanos dependem incessantemente de um sistema de reconhecimento efetivo contra infecções para sobreviver. Dentre as diversas proteínas que compõem a resposta imune inata estão os receptores do tipo Toll (TLR Toll-like Receptors), que possuem a função de reconhecer padrões moleculares associados a patógenos e dar início a uma resposta imune adequada. O carcinoma do colo uterino é uma das principais causas de morte de mulheres por câncer mundialmente, sendo o terceiro tipo de câncer mais comum entre mulheres. Este tipo de neoplasia é vinculada etiologicamente à infecção pelo Papilomavírus humano (HPV). Dentre as principais proteínas virais, E6 e E7 são responsáveis pela manipulação dos processos celulares para promover ciclo viral, sendo essenciais no processo de transformação celular. Nesse contexto, o objetivo deste trabalho foi investigar a importância da via de sinalização de TLRs sobre a infecção por HPV. O polimorfismo rs5743836, na região promotora de TLR9, capaz de alterar a expressão deste receptor, foi estudado quanto à influência sobre a história natural da infecção por HPV em uma coorte de mulheres brasileiras; nenhuma associação relevante foi encontrada, indicando que este polimorfismo não interfere significativamente na resposta à infecção e risco de desenvolvimento de lesões no colo do útero causadas por HPV. Proteínas componentes da via de TLRs demonstraram serem alvos de interação com E6 de HPV16; dentre elas, o notável adaptador MyD88 e IKKε, enzima ativadora de importantes transfatores do sistema imune. Estas interações foram aqui estudadas. A interação de E6 com MyD88 resultou em estabilização da proteína viral, o que parece não depender do sítio LxxLL presente em MyD88, como ocorre com outros parceiros moleculares de E6. O sítio de interação de E6 com IKKε coincide com a região onde se localiza o sítio catalítico desta enzima, sugerindo a ação de E6 na ativação de proteínas alvo de IKKε. Esta interação foi observada em queratinócitos, células alvo das infecções por HPV. A produção de citocinas foi afetada por E6 de HPV16, resultando num aumento da quantidade de IL-8 e IL-6; a indução desta citocina poderia ser explicada pela ativação de IKKε. Estes resultados apontam para a capacidade do HPV16 de interferir com o sistema imune, contribuindo para o processo de carcinogênese

Humans constantly rely on an effective recognition system against infections in order to survive. Among various proteins that compose the innate immune response, Toll-like Receptors (TLRs) have the role to recognize pathogen associated molecular patterns and initiate a proper immune response. The cervical cancer is one of the main causes of women death worldwide, being the third most common cancer type among women. This type of neoplasia is etiologically associated with the Human papillomavirus (HPV) infection. E6 and E7, two main viral proteins, are responsible for manipulating the cellular processes to promote the virus' life-cycle, being essential to the cellular transformation process. In the context, the objective of this work was to investigate the relevance of the TLR signaling pathway on the HPV infection. The rs5743836 polymorphism, in the TLR9 promoter region, capable of altering this receptor's expression, was studied regarding its influence on the natural history of HPV infection in a Brazilian women cohort; no relevant association was found, indicating that this polymorphism does not interfere significantly in the infection response and risk of developing cervix lesions caused by HPV. Component proteins of TLR pathway were shown to be interaction targets of HPV16 E6; among them, the notable adaptor MyD88 and IKKε, enzyme that activates important immune system transfactors. These interactions were studied in this work. The interaction of E6 with MyD88 resulted in the stabilization of the viral protein, which seems independent of the LxxLL site present on MyD88, as in other E6 molecular partners. The interaction site on IKK with E6 matches with the region containing the enzyme's catalytic site, suggesting an influence of E6 in the activation of IKKε target proteins. This interaction was observed in keratinocytes, natural targets of HPV infections. The cytokines production was altered by HPV16 E6, resulting in an increase of IL-8 and IL-6 concentration; the induction of the latter could be explained by the activation of IKKε. These results point to the ability of HPV16 of interfering with the immune system, contributing to the carcinogenesis process

Papilomavírus humano: biologia viral e carcinogênese / Papillomavirus human: viral biology and carcinogenesis

O Papilomavírus humano (HPV) exerce um papel central na carcinogênese do colo uterino. Os mecanismos utilizados pelos HPVs de alto risco para influenciar o ciclo de divisão celular, levando-o à sua desregulação e, consequentemente, para a progressão de lesões, incluem fatores inerentes ao vírus e à sua inter-relação com a célula hospedeira. Tais interferências no metabolismo celular poderão causar modificações morfológicas e funcionais, promovendo o aparecimento de neoplasias. Compreendendo a importância do conhecimento dos processos biológicos e moleculares utilizados pelo HPV na carcinogênese para o diagnóstico precoce e na avaliação prognóstica da doença, o objetivo deste trabalho foi buscar na literatura científica a relação da biologia viral do HPV com o desenvolvimento do câncer de colo útero e novas descobertas.(AU)

The Human papillomavirus (HPV) plays a central role in carcinogenesis of the cervix. The mechanisms used by high-risk HPVs to influence the cell division cycle taking it to its deregulation and consequently for progression of lesions include factors related to the virus and its interrelationship with the host cell. Changes in cellular metabolism can cause morphological and functional changes, promoting the appearance of tumors. Understanding the importance of knowledge of the biological and molecular processes used by HPV in carcinogenesis for early diagnosis and prognostic evaluation of the disease, the objective was to search the scientific literature regarding the HPV?s viral biology to the development of cervical cancer and new discoveries.(AU)

Progressive loss of E-cadherin immunoexpression during cervical carcinogenesis

PURPOSE: To investigate E-cadherin immunoexpression during cervical carcinogenesis. METHODS: We assessed the immunohistochemical expression of E-cadherin in squamous intraepithelial lesions (SIL - 52 cases), squamous cell carcinoma (SCC) of the uterine cervix (23 cases) and also in eight cases of cervicitis. RESULTS: The results show very different E-cadherin membrane expression levels when cervicitis (88%), SILs (73%) and SCC (17%) were compared. In SILs, higher E-cadherin loss was seen in less differentiated cells in the basal third of the epithelium. This study suggests that the absence of E-cadherin expression in the membrane is a molecular event that is observed more often in SCC of the uterine cervix than in SILs or cervicitis. CONCLUSIONS: E-cadherin is an essential molecule during the process of cervical carcinogenesis and in this context exhibits a different expression pattern according to the epithelial thickness layer. .

Rol de las metaloproteinasas y sus inhibidores en patología tumoral / Role of metalloproteinases and their inhibitors in tumors

Las metaloproteinasas (MMPs) intervienen en diversos procesos fisiológicos y patológicos del organismo. Regulan, por ejemplo, las vías de señalización que controlan el crecimiento celular, la inflamación y la angiogénesis. Cumplen funciones moduladoras en el complejo microambiente tumoral interviniendo en las etapas tempranas de la carcinogénesis, en la invasión y la producción de metástasis tumorales. Participan en el procesamiento de moléculas bioactivas como citoquinas, quemoquinas y factores de crecimiento. Las MMPs tienen como substrato a las proteínas de la matriz extracelular (MEC) y su actividad es regulada por inhibidores endógenos (TIMPs). El adecuado balance entre ambas moléculas es fundamental para mantener la homeostasis. Debido al papel que desempeñan en diferentes etapas de la biología del cáncer, son un blanco potencial para futuras estrategias en la terapéutica de esta enfermedad.

Metalloproteinases (MMPs) are involved in different physiological and pathological processes. They regulate several signaling pathways in cell growth, inflammation and angiogenesis. The MMPs modulate the complex tumor microenvironment and are involved in the early stages of carcinogenesis, tumor invasion and metastasic processes. MMPs participate in the processing of bioactive molecules such as cytokines, chemokines and growth factors. Their substrates are the extracellular matrix proteins and endogenous inhibitors (TIMPs) regulate their functions. The accurate balance between these two molecules, MMPs and TIMPs, is critical for maintaining homeostasis. Due to their role in cancer biology, MMPs are potential targets for fu ture therapeutic strategies of this malignant disease.