Casticin Attenuates Stemness in Cervical Cancer Stem-Like Cells by Regulating Activity and Expression of DNMT1 / 中国结合医学杂志

OBJECTIVE@#To explore whether casticin (CAS) suppresses stemness in cancer stem-like cells (CSLCs) obtained from human cervical cancer (CCSLCs) and the underlying mechanism.@*METHODS@#Spheres from HeLa and CaSki cells were used as CCSLCs. DNA methyltransferase 1 (DNMT1) activity and mRNA levels, self-renewal capability (Nanog and Sox2), and cancer stem cell markers (CD133 and CD44), were detected by a colorimetric DNMT activity/inhibition assay kit, quantitative real-time reverse transcription-polymerase chain reaction, sphere and colony formation assays, and immunoblot, respectively. Knockdown and overexpression of DNMT1 by transfection with shRNA and cDNA, respectively, were performed to explore the mechanism for action of CAS (0, 10, 30, and 100 nmol/L).@*RESULTS@#DNMT1 activity was increased in CCSLCs compared with HeLa and CaSki cells (P<0.05). In addition, HeLa-derived CCSLCs transfected with DNMT1 shRNA showed reduced sphere and colony formation abilities, and lower CD133, CD44, Nanog and Sox2 protein expressions (P<0.05). Conversely, overexpression of DNMT1 in HeLa cells exhibited the oppositive effects. Furthermore, CAS significantly reduced DNMT1 activity and transcription levels as well as stemness in HeLa-derived CCSLCs (P<0.05). Interestingly, DNMT1 knockdown enhanced the inhibitory effect of CAS on stemness. As expected, DNMT1 overexpression reversed the inhibitory effect of CAS on stemness in HeLa cells.@*CONCLUSION@#CAS effectively inhibits stemness in CCSLCs through suppression of DNMT1 activation, suggesting that CAS acts as a promising preventive and therapeutic candidate in cervical cancer.

Knocking down LSD1 inhibits the stemness features of colorectal cancer stem cells

As a top leading cause of cancer death in many countries, colorectal cancer (CRC) has drawn increasing attention to the study of the pathological mechanism. According to the "cancer stem cell hypothesis", malignancies originate from a small fraction of cancer cells that show self-renewal properties to initiate and sustain tumor growth and tumor metastasis. Therefore, these cancer stem cells (CSC) probably play important roles in tumor recurrence, metastasis, and drug resistance. Previous research reported that lysine-specific histone demethylase 1 (LSD1) maintains cancer stemness through up-regulating stemness markers SOX2 and OCT4. CD133 is believed to be the most robust surface marker for CRC stem cells, however the regulatory effect of LSD1 on stemness of CD133+ CRC has never been reported. In this study, our objectives included: 1) to isolate pure CD133+ and CD133− cells from SW620 cell line; 2) to investigate the effect of LSD1 on the characteristics of CD133+ stem cancer cells by knocking down the target gene. Results suggested that the SW620 cell line had both CD133+ and CD133− subsets. The CD133+ subset exhibited more CSC-like characteristics compared with the CD133− subset with higher viability, colony formation rate, migration and invasion rate, resistance to anti-cancer drugs, and apoptosis in vitro. The CD133+ also induced faster tumor formation and larger tumors in vivo. In the LSD1-knockdown CD133+ cells, the CSC-like characteristics had been all weakened. We conclude that LSD1 was important for CSCs to maintain their "stemness" features, which could be a potential therapeutic target of CRC.

Are stem cell marker expression and cd133 analysis relevant to differentiate colorectal cancer? / A expressão de marcadores de células-tronco e a análise do cd133 são relevantes na diferenciação do câncer colorretal?

ABSTRACT Background: CD133 and AXL have been described as cancer stem cell markers, and c-MYC as a key regulatory cellular mechanism in colorectal cancer (CRC). Aim: Evaluate the prognostic role of the biomarkers CD133, AXL and c-MYC and their association with clinicopathologic characteristics in colorectal adenocarcinomas and adenomas. Methods: A total of 156 patients with UICC stage I-IV adenocarcinomas (n=122) and adenomas (n=34) were analyzed. Tissue microarrays (TMA) from primary tumors and polyps for CD133, c-MYC and AXL expression were performed and analyzed for their significance with clinicopathologic characteristics. Results: Poorly differentiated adenocarcinomas and disease progression were independent risk factors for poor overall survival. The median overall survival time was 30 months. Positive CD133 expression (35.9% of all cases), particularly of right-sided CRCs (44.8% of the CD133+ cases), was negatively correlated with death in the univariate analysis, which did not reach significance in the multivariate analysis. c-MYC (15.4% of all cases) was predominantly expressed in advanced-stage patients with distant (non-pulmonary/non-hepatic) metastasis. AXL expression was found only occasionally, and predominantly dominated in adenomas, with less penetrance in high-grade dysplasia. Conclusions: CD133 expression was not associated with inferior overall survival in CRC. While AXL showed inconclusive results, c-MYC expression in primary CRCs was associated with distant metastasis.

RESUMO Racional: CD133 e AXL são descritos na literatura como marcadores de células-tronco tumorais, e c-MYC cumpre papel chave como mecanismo de regulação celular no câncer colorretal (CCR). Objetivo: Avaliar o papel prognóstico dos biomarcadores CD133, AXL e c-MYC e sua associação com características clinicopatológicas de adenocarcinomas e adenomas colorretais. Métodos: Um total de 156 pacientes com adenocarcinomas de estádio UICC I-IV (n=122) e adenomas (n=34) colorretais foram avaliados. Microarranjos teciduais (TMA) dos tumores primários e adenomas foram realizados em busca de expressão de CD133, c-MYC e AXL, com posterior análise de relação significativa com características clinicopatológicas. Resultados: Adenocarcinomas pobremente diferenciados e progressão de doença foram fatores de risco independentes para má sobrevida global. A taxa mediana de sobrevida global foi de 30 meses. Expressão positiva de CD133 (35,9% dos casos), particularmente em cânceres de cólon direito (44,8% dos casos CD133+), correlacionou-se negativamente com óbito na análise univariada, sem significância estatística na análise multivariada. c-MYC (15,4% dos casos) teve predomínio de expressão em pacientes com estádio avançado com metástases distantes (não-pulmonares/não-hepáticas). Expressão de AXL foi pouco encontrada, com predomínio em adenomas, com menor penetrância em displasia de alto grau. Conclusão: Expressão de CD133 não se associou com sobrevida global inferior em CCR. Enquanto AXL demonstrou resultados inconclusivos, expressão de c-MYC em tumores primários se associou-se à metástases à distância.

Correlation of Cancer Stem-Cell Markers OCT4, SOX2, and NANOG with Clinicopathological Features and Prognosis in Operative Patients with Rectal Cancer

PURPOSE: To investigate the association of cancer stem-cell markers [octamer-binding transcription factor 4 (OCT4), sex determining region Y-box 2 (SOX2), and Nanog homebox (NANOG)] expression with clinicopathological properties and overall survival (OS) in operative rectal cancer (RC) patients receiving adjuvant therapy. MATERIALS AND METHODS: 153 patients with primary RC receiving surgery were enrolled. Tumor tissue and paired adjacent normal tissue sample were collected, and OCT4, SOX2, and NANOG expressions were assessed by immunofluorescent staining. The median follow-up duration was 5.2 years, and the last follow-up date was August 2016. RESULTS: Tumor tissue OCT4 (p < 0.001), SOX2 (p=0.003), and NANOG (p < 0.001) expressions were higher than those in adjacent tissue. OCT4 expression was positively correlated with pathological grade (R=0.185, p=0.022), tumor size (R=0.224, p=0.005), and N stage (R=0.170, p=0.036). NANOG expression was positively associated with tumor size (R=0.169, p=0.036). Kaplan-Meier suggested that OCT4+ was associated with worse OS compared with OCT4− (p < 0.001), while no association of SOX2 (p=0.121) and NANOG expressions (p=0.195) with OS was uncovered. Compared with one or no positive marker, at least two positive markers were associated with shorter OS (p < 0.001), while all three positive markers were correlated with worse OS compared with two or less positive markers (p < 0.001). Multivariate Cox's analysis revealed that OCT4+ (p < 0.001) and N stage (p=0.046) were independent factors for shorter OS. CONCLUSION: Tumor tissue OCT4 expression was correlated with poor differentiation, tumor size, and N stage, and it can serve as an independent prognostic biomarker in operative patients with RC receiving adjuvant therapy.

Cancer Stem Cells are Depolarized Relative to Normal Stem Cells Derived from Human Livers

ABSTRACT Introduction and aim. The inability to distinguish cancer (CSCs) from normal stem cells (NSCs) has hindered attempts to identify safer, more effective therapies for hepatocellular carcinoma (HCC). The aim of this study was to document and compare cell membrane potential differences (PDs) of CSCs and NSCs derived from human HCC and healthy livers respectively and determine whether altered GABAergic innervation could explain the differences. Material and methods. Epithelial cell adhesion molecule (EpCAM) positive stem cells were isolated from human liver tissues by magnetic bead separations. Cellular PDs were recorded by microelectrode impalement of freshly isolated cells. GABAA receptor subunit expression was documented by reverse transcriptase polymerase chain reaction (RT-PCR) and immunofluorescence. Results. CSCs were significantly depolarized (-7.0 ± 1.3 mV) relative to NSCs (-23.0 ± 1.4 mV, p < 0.01). The depolarized state was associated with different GABAA receptor subunit expression profiles wherein phasic transmission, represented by GAGAA α3 subunit expression, was prevalent in CSCs while tonic transmission, represented by GABAA α6 subunit expression, prevailed in NSCs. In addition, GABAA subunits α3, β3, γ3 and δ were strongly expressed in CSCs while GABAA π expression was dominant in NSCs. CSCs and NSCs responded similarly to GABAA receptor agonists (ΔPD: 12.5 ± 1.2 mV and 11.0 ± 3.5 mV respectively). Conclusion. The results of this study indicate that CSCs are significantly depolarized relative to NSCs and these differences are associated with differences in GABAA receptor subunit expression. Together they provide new insights into the pathogenesis and possible treatment of human HCC.

Impact of extracellular alkalinization on the survival of human CD24-/CD44+ breast cancer stem cells associated with cellular metabolic shifts

Cancer stem cells reside in a distinct region within the tumor microenvironment that it is believed to play a fundamental role in regulating stemness, proliferation, survival, and metabolism of cancer cells. This study aimed to analyze the effect of extracellular alkalinization on metabolism and survival of human CD24-/CD44+ breast cancer stem cells (BCSCs). BCSCs were cultured in alkalinized DMEM-F12 and incubated at 37°C, 5% CO2, and 20% O2 for 30 min, 6, 24, and 48 h. After each incubation period, we analyzed the modulation of various mRNA expressions related to pH and cellular metabolic regulation using the qRT-PCR. Metabolic state was measured using colorimetric and fluorometric assays. To examine cell proliferation and apoptosis, we used trypan blue and annexin V/propidium iodide assay, respectively. This study demonstrated that alkalinization could stimulate extracellular carbonic anhydrase (CAe) activity, as well as CA9 and HIF1α expression. Under alkaline pH and HIF1α regulation, glucose consumption, extracellular lactate production, and LDH activity of BCSCs were upregulated while O2 consumption was downregulated. These metabolic shifts seemed to promote apoptosis and suppress the proliferation of BCSCs. To conclude, modulation of the extracellular environment through alkalinization could change the metabolic states of BCSCs, which in turn affect the cell survival.

Expression of CD90 and P75NTR stem cell markers in ameloblastomas: a possible role in their biological behavior

Abstract Multicystic and unicystic ameloblastomas are benign odontogenic tumors that present distinct biological behavior. The investigation of stem cells has become an important branch of tumor biology, with several studies addressing the possible role of these cells in tumor growth, angiogenesis, progression, infiltration and invasiveness. This study evaluated the immunohistochemical expression of CD90(Thy-1) and P75NTR stem cell markers in multicystic and unicystic ameloblastomas. Seventeen (17) samples of ameloblastomas (multicystic, n = 10; unicystic, n = 7) were submitted to immunohistochemical reactions and graded semi-quantitatively. The Kolmogorov-Smirnov test was used to verify possible differences in CD90 and P75NTR expressions between multicystic and unicystic ameloblastomas (p < 0.05). CD90 immunostaining was observed in all multicystic ameloblastoma specimens (n = 10), in the cytoplasm of the fibroblasts and vascular endothelial cells of the tumor stroma, near the neoplastic odontogenic epithelia. The staining of stromal CD90 was significantly higher in multicystic than in unicystic ameloblastomas (p = 0.003). Nuclear P75NTR immunostaining was observed in all ameloblastoma specimens. A significant difference was seen in the epithelial staining of P75NTR between multicystic and unicystic types (p = 0.007). The increased expression of CD90 and P75NTR found in multicystic ameloblastomas suggests a behavioral biological difference between multicystic and unicystic ameloblastomas, as well as a difference in ameloblastoma development.

Silencing of ABCG2 by MicroRNA-3163 Inhibits Multidrug Resistance in Retinoblastoma Cancer Stem Cells

To investigate the function and regulation mechanism of ATP-binding cassette, subfamily G, member 2 (ABCG2) in retinoblastoma cancer stem cells (RCSCs), a long-term culture of RCSCs from WERI-Rb1 cell line was successfully established based on the high expression level of ABCG2 on the surface of RCSCs. To further explore the molecular mechanism of ABCG2 on RCSCs, a microRNA that specifically targets ABCG2 was predicted. Subsequently, miR-3163 was selected and confirmed as the ABCG2-regulating microRNA. Overexpression of miR-3163 led to a significant decrease in ABCG2 expression. Additionally, ABCG2 loss-of-function induced anti-proliferation and apoptosis-promoting functions in RCSCs, and multidrug resistance to cisplatin, carboplatin, vincristine, doxorubicin, and etoposide was greatly improved in these cells. Our data suggest that miR-3163 has a significant impact on ABCG2 expression and can influence proliferation, apoptosis, and drug resistance in RCSCs. This work may provide new therapeutic targets for retinoblastoma.

A família vivenciando o processo de recuperação da criança pós-alta hospitalar / La familia que vive el proceso de recuperación de niños después del alta hospitalaria / The family living the child recovery process after hospital discharge

RESUMOObjetivo:compreender o significado atribuído pela família à sua vivência no processo de recuperação da criança acometida por doença aguda, após a alta hospitalar e elaborar um modelo teórico a respeito dessa experiência. O Interacionismo Simbólico foi adotado como referencial teórico e a Grounded Theory como metodológico.Método:os dados foram coletados por meio de entrevista e observação participante com 11 famílias, totalizando 15 entrevistas. A análise levou à formulação de um Modelo Teórico composto por dois fenômenos interativos: Mobilizando-se para resgatar o equilíbrio de seu funcionamento e Sofrendo com a possibilidade de reintegrar a criança.Resultados:estes revelaram que a família mantém-se em alerta para identificar precocemente alterações de saúde da criança na tentativa de evitar uma reinternação.Conclusão:os efeitos da doença e hospitalização continuam a manifestar-se no funcionamento familiar, gerando sofrimento mesmo após a alta e a recuperação da criança.

RESUMENObjetivo:comprender el significado atribuido por la familia de su experiencia en la recuperación de los niños afectados por el proceso de la enfermedad aguda, después de la descarga y desarrollar un modelo teórico sobre la experiencia. El Interaccionismo Simbólico fue adoptado como un teórico y la Teoría Fundamentada como metodológico.Método:los datos fueron recolectados a través de entrevistas y observación participante con 11 familias, con un total de 15 entrevistas. El análisis dio lugar a la formulación de un modelo teórico consta de dos fenómenos interactivos: Movilización para restaurar el balance de su funcionamiento y Sufriendo con la posibilidad de reinternar el niño.Resultados:éstos revelaron que la familias e mantiene en alerta para la identificación temprana de la salud el niño en un intento de evitar un reingreso.Conclusión:Los efectos de la enfermedad y la hospitalización aún se manifiesta en el funcionamiento familiar, que produce sufrimiento, incluso después de la descarga y la recuperación del niño.

ABSTRACTObjective:to understand the meaning attributed by the family to its experience in the recovery process of a child affected by an acute disease after discharge, and to develop a theoretical model of this experience. Symbolic interactionism was adopted as a theoretical reference, and grounded theory was adopted as a methodological reference.Method:data were collected through interviews and participant observation with 11 families, totaling 15 interviews. A theoretical model consisting of two interactive phenomena was formulated from the analysis: Mobilizing to restore functional balance and Suffering from the possibility of a child's readmission.Results:the family remains alert to identify early changes in the child's health, in an attempt to avoid rehospitalization.Conclusion:the effects of the disease and hospitalization continue to manifest in family functioning, causing suffering even after the child's discharge and recovery.

Prevalência e fatores associados ao tabagismo entre fumicultores na região Sul do Brasil / Prevalencia y factores asociados al hábito de fumar entre los cultivadores de tabaco en el sur de Brasil / Prevalence and factors associated with smoking among tobacco growers in southern Brazil

RESUMOObjetivo:identificar a prevalência e fatores associados ao tabagismo em fumicultores.Método:estudo descritivo, do tipo transversal. A coleta de dados ocorreu em 2012 por inquérito domiciliar e entrevistas, incluindo aplicação de instrumento estruturado e escala de Fargeström.Resultados:foram incluídos 100 fumicultores, média de idade 46,9±10,8 anos; 90 (90%) casados; 72 (72%) cor branca; composição familiar de 3,7±1,1 pessoas, mediana de filhos de 3(1-3) e média tempo de estudo 6±2,5 anos. Obteve-se prevalência de 17% de fumantes, os quais apresentaram menor escolaridade (p=0,010) e menor número de pessoas no domicílio (p=0,049).Conclusão:a prevalência do tabagismo entre fumicultores foi maior que a média nacional, porém, com baixa dependência da nicotina, o que pode facilitar o processo de cessação do tabagismo. Destaca-se a necessidade de implantar um programa para o controle do tabagismo junto a este grupo.

RESUMENObjetivo:identificar la prevalencia y factores asociados con el consumo de tabaco en el cultivo del tabaco.Método:estudio descriptivo, transversal. Los datos fueron recolectados por medio de entrevistas en el 2012, que incluye la aplicación de un instrumento estructurado y escala Fargeström.Resultados:100 cultivadores se incluyeron, la edad media 46,9±10,8 años; 90(90%) se casó; 72(72%) blanco, la composición familiar de 3,7±1,1 personas, mediana de 3 niños (1-3) y el tiempo promedio de estudio de 6±2,5 años. La prevalencia de tabaquismo fue del 17%, que tenía menos educación (p=0,010) y un menor número de personas en hogar (p=0,049).Conclusión:la prevalencia de tabaquismo entre los productores de tabaco fue mayor que el promedio nacional, pero la dependencia de la nicotina fue baja, lo que puede facilitar el proceso de dejar de fumar. Destaca la necesidad de implementar un programa de control del tabaquismo entre los cultivadores de tabaco.

ABSTRACTObjective:identify the prevalence and factors associated with smoking in tobacco growers.Method:descriptive, cross-sectional research. Data collection occurred in 2012 through household survey and interviews, including application of a structured instrument and scale Fargeström.Results:there were 100 growers included, average age of 46,9 ± 10,8 years; 90(90%) married; 72(72%) white, average family composition 3,7±1,1 people; median number of children 3(1-3), and the average study time 6±2,5. The prevalence of smoking among tobacco growers was 17%, which had less education (p=0.010) and fewer people in the household (p=0.049).Conclusion:the prevalence of smoking among tobacco growers was higher than the national average, but the nicotine dependence was low, which can facilitate the smoking cessation process. Highlights the need to implement a program to control smoking among tobacco growers.

The potential role of COX-2 in cancer stem cell-mediated canine mammary tumor initiation: an immunohistochemical study

Increasing evidence suggests that cancer stem cells (CSCs) are responsible for tumor initiation and maintenance. Additionally, it is becoming apparent that cyclooxygenase (COX) signaling is associated with canine mammary tumor development. The goals of the present study were to investigate COX-2 expression patterns and their effect on CSC-mediated tumor initiation in primary canine mammary tissues and tumorsphere models using immunohistochemistry. Patterns of COX-2, CD44, octamer-binding transcription factor (Oct)-3/4, and epidermal growth factor receptor (EGFR) expression were examined in malignant mammary tumor (MMT) samples and analyzed in terms of clinicopathological characteristics. COX-2 and Oct-3/4 expression was higher in MMTs compared to other histological samples with heterogeneous patterns. In MMTs, COX-2 expression correlated with tumor malignancy features. Significant associations between COX-2, CD44, and EGFR were observed in low-differentiated MMTs. Comparative analysis showed that the levels of COX-2, CD44, and Oct-3/4 expression varied significantly among TSs of three histological grades. Enhanced COX-2 staining was consistently observed in TSs. Similar levels of staining intensity were found for CD44 and Oct-3/4, but EGFR expression was weak. Our findings indicate the potential role of COX-2 in CSC-mediated tumor initiation, and suggest that COX-2 inhibition may help treat canine mammary tumors by targeting CSCs.

Knockdown of 14-3-3zeta enhances radiosensitivity and radio-induced apoptosis in CD133+ liver cancer stem cells

14-3-3zeta is related to many cancer survival cellular processes. In a previous study, we showed that silencing 14-3-3zeta decreases the resistance of hepatocellular carcinoma (HCC) to chemotherapy. In this study, we investigated whether silencing 14-3-3zeta affects the radioresistance of cancer stem-like cells (CSCs) in HCC. Knockdown of 14-3-3zeta decreased cell viability and the number of spheres by reducing radioresistance in CSCs after gamma-irradiation (IR). Furthermore, the levels of pro-apoptotic proteins were upregulated in CSCs via silencing 14-3-3zeta after IR. These results suggest that 14-3-3zeta knockdown enhances radio-induced apoptosis by reducing radioresistance in liver CSCs.

Cultivation and identification of colon cancer stem cell-derived spheres from the Colo205 cell line

Our group established a method to culture spheres under serum-free culture condition. However, the biological characteristics and the tumorigenicity of spheres are unknown. Here, we demonstrate that sphere cells expressed high levels of the putative colorectal cancer stem cell markers CD133 and CD44. The CD133-positive rates were 13.27 ± 5.62, 52.71 ± 16.97 and 16.47 ± 2.45 percent in sphere cells, regular Colo205 cells and differentiated sphere cells, respectively, while the CD44-positive rates were 62.92 ± 8.38, 79.06 ± 12.10 and 47.80 ± 2.5 percent, respectively, and the CD133/CD44-double-positive rates were 10.77 ± 4.96, 46.89 ± 19.17 and 12.41 ± 2.27 percent, respectively (P < 0.05). Cancer sphere cells formed crypt-like structures in 3-D culture. Moreover, cells from cancer spheres exhibited more tumorigenicity than regular Colo205 cells in a xenograft assay. The cancer sphere cells displayed much higher oncogenicity than regular Colo205 cells to initiate neoplasms, as assayed by H&E staining, Musashi-1 staining and electron microscopy. Our findings indicated that the sphere cells were enriched with cancer stem cells (CSCs), and exhibited more proliferation capacity, more differentiation potential and especially more tumorigenicity than regular Colo205 cells in vitro and in vivo. Further isolation and characterization of these CSCs may provide new insights for novel therapeutic targets and prognostic markers.

Perspective beyond Cancer Genomics: Bioenergetics of Cancer Stem Cells

Although the notion that cancer is a disease caused by genetic and epigenetic alterations is now widely accepted, perhaps more emphasis has been given to the fact that cancer is a genetic disease. It should be noted that in the post-genome sequencing project period of the 21st century, the underlined phenomenon nevertheless could not be discarded towards the complete control of cancer disaster as the whole strategy, and in depth investigation of the factors associated with tumorigenesis is required for achieving it. Otto Warburg has won a Nobel Prize in 1931 for the discovery of tumor bioenergetics, which is now commonly used as the basis of positron emission tomography (PET), a highly sensitive noninvasive technique used in cancer diagnosis. Furthermore, the importance of the cancer stem cell (CSC) hypothesis in therapy-related resistance and metastasis has been recognized during the past 2 decades. Accumulating evidence suggests that tumor bioenergetics plays a critical role in CSC regulation; this finding has opened up a new era of cancer medicine, which goes beyond cancer genomics.

Brain Tumor Stem Cells as Therapeutic Targets in Models of Glioma

At this time, brain tumor stem cells remain a controversial hypothesis while malignant brain tumors continue to present a dire prognosis of severe morbidity and mortality. Yet, brain tumor stem cells may represent an essential cellular target for glioma therapy as they are postulated to be the tumorigenic cells responsible for recurrence. Targeting oncogenic pathways that are essential to the survival and growth of brain tumor stem cells represents a promising area for developing therapeutics. However, due to the multiple oncogenic pathways involved in glioma, it is necessary to determine which pathways are the essential targets for therapy. Furthermore, research still needs to comprehend the morphogenic processes of cell populations involved in tumor formation. Here, we review research and discuss perspectives on models of glioma in order to delineate the current issues in defining brain tumor stem cells as therapeutic targets in models of glioma.

TSH signalling and cancer

Thyroid cancers are the most frequent endocrine neoplasms and mutations in the thyrotropin receptor (TSHR) are unusually frequent. Here we present the state-of-the-art concerning the role of TSHR in thyroid cancer and discuss it in light of the cancer stem cell theory or the classical view. We briefly review the gene and protein structure updating the cancer related TSHR mutations database. Intriguingly, hyperfunctioning TSHR mutants characterise differentiated cancers in contrast to undifferentiated thyroid cancers which very often bear silenced TSHR. It remains unclear whether TSHR alterations in thyroid cancers play a role in the onset or they appear as a consequence of genetic instability during evolution, but the presence of functional TSHR is exploited in therapy. We outline the signalling network build up in the thyrocyte between TSHR/PKA and other proliferative pathways such as Wnt, PI3K and MAPK. This networks integrity surely plays a role in the onset/evolution of thyroid cancer and needs further research. Lastly, future investigation of epigenetic events occurring at the TSHR and other loci may give better clues for molecular based therapy of undifferentiated thyroid carcinomas. Targeted demethylating agents, histone deacetylase inhibitors combined with retinoids and specific RNAis may help treatment in the future.

Os cânceres de tiróide são as neoplasias endócrinas mais frequentes e as mutações no receptor de tirotrofina (TSHR) são incomumente frequentes. Nesta revisão nós apresentamos o "estado da arte" com relação ao papel do TSHR no câncer de tiróide e o discutimos à luz da teoria da célula matriz do câncer ou a visão clássica. Revisamos brevemente a estrutura do gene e da proteína, atualizando a base de dados das mutações do TSHR relacionadas ao câncer. Curiosamente, mutações do TSHR com hiperfunção caracterizam cânceres diferenciados, em contraste com os cânceres de tiróide indiferenciados, os quais muito comumente mostram TSHR silenciados. Permanece obscuro se as alterações do TSHR em cânceres de tiróide têm algum papel no surgimento ou se elas aparecem como conseqüência da instabilidade genética durante seu desenvolvimento, mas a presença de TSHR funcional é explorada na terapia. Nós delineamos a rede de sinalizacão desenvolvida no tirócito entre TSHR/PKA e outras vias proliferativas como a Wnt, PI3k e MAPK. A integridade desta rede certamente tem um papel no surgimento/evolução do câncer de tiróide e necessita de novas pesquisas. Finalmente, novas investigacões sobre os eventos epigenéticos que ocorrem no TSHR e outros locais poderão trazer novas informações para uma terapia de base molecular nos carcinomas indiferenciados de tiróide. Agentes demetilantes direcionados, inibidores da histona-deacetilase, combinados com retinóides e RNAs específicos poderão auxiliar no tratamento futuro.