Efecto de las alteraciones genéticas y epigenéticas de la cadherina E y su expresión en la transcripción en la propensión al cáncer de mama / Effect of genetics, epigenetics and variations in the transcriptional expression of cadherin-E in breast cancer susceptibility

RESUMEN Introducción. La cadherina E (CDH1) cumple un papel importante en la transición epitelio-mesénquima y está relacionada con la invasión y las metástasis en varios tipos de carcinomas. Sin embargo, el efecto de las mutaciones y 'epimutaciones' germinales en la propensión al cáncer de mama no es claro. Objetivo. Evaluar el polimorfismo rs5030625, los cambios en el patrón de metilación del promotor y la expresión en la transcripción del gen CDH1 en pacientes con cáncer de mama. Materiales y métodos. Se tomaron muestras de sangre periférica de 102 pacientes con cáncer de mama y 102 mujeres de control. La genotipificación del polimorfismo rs5030625 se hizo mediante reacción en cadena de la polimerasa (PCR) y análisis de polimorfismos de longitud del fragmento de restricción; la PCR y el análisis de disociación de alta resolución sensible a metilación se emplearon para determinar el estado y el nivel de metilación del promotor del CDH1; por último, el nivel de expresión en la transcripción del CDH1 se evaluó mediante PCR cuantitativa con transcripción inversa. Resultados. Los resultados no evidenciaron asociación entre el polimorfismo rs5030625 y el cáncer de mama. Se encontraron perfiles aberrantes de metilación del promotor del CDH1 en las pacientes con cáncer de mama relacionados con las primeras etapas de desarrollo del cáncer. La disminución de la expresión del CDH1 se asoció con la presencia de metástasis y el estado de metilación del promotor. Conclusión. Las alteraciones en el CDH1 se asociaron con la invasión y las metástasis en el cáncer de mama. Se proporcionó evidencia adicional sobre la relevancia del CDH1 en el desarrollo y la progresión del cáncer de mama.

ABSTRACT Introduction: Cadherin-E (CDH1) is an important regulator of epithelial-mesenchymal transition, invasion and metastasis in many carcinomas. However, germinal epimutations and mutations effect in breast cancer susceptibility is not clear. Objective: To evaluate rs334558 polymorphism, promoter methylation status and CDH1 expression profile in breast cancer patients. Materials and methods: We collected peripheral blood samples from 102 breast cancer patients and 102 healthy subjects. The identification of rs334558 polymorphism was performed using PCR-RFLP, while methylation-specific PCR (MSP) and methylation-sensitive high-resolution melting (MS-HRM) were used to explore CDH1 methylation status; finally, CDH1 transcriptional expression profile was evaluated using RT-qPCR. Results: We found no association between rs334558 polymorphism and breast cancer. Aberrant promoter methylation profile was found in breast cancer patients and it was related with early cancer stages. CDH1 down-regulation was significantly associated with metastasis and promoter methylation. Conclusion: CDH1 alterations were associated with invasion and metastasis in breast cancer. Our results offer further evidence of CDH1 relevance in breast cancer development and progression.

The NER-related gene GTF2H5 predicts survival in high-grade serous ovarian cancer patients / 부인종양

OBJECTIVE: We aimed to evaluate the prognostic and predictive value of the nucleotide excision repair-related gene GTF2H5, which is localized at the 6q24.2-26 deletion previously reported by our group to predict longer survival of high-grade serous ovarian cancer patients. METHODS: In order to test if protein levels of GTF2H5 are associated with patients' outcome, we performed GTF2H5 immunohistochemical staining in 139 high-grade serous ovarian carcinomas included in tissue microarrays. Upon stratification of cases into high- and low-GTF2H5 staining categories (> and < or = median staining, respectively) Kaplan-Meier and log-rank test were used to estimate patients' survival and assess statistical differences. We also evaluated the association of GTF2H5 with survival at the transcriptional level by using the on-line Kaplan-Meier plotter tool, which includes gene expression and survival data of 855 high-grade serous ovarian cancer patients from 13 different datasets. Finally, we determined whether stable short hairpin RNA-mediated GTF2H5 downregulation modulates cisplatin sensitivity in the SKOV3 and COV504 cell lines by using cytotoxicity assays. RESULTS: Low expression of GTF2H5 was associated with longer 5-year survival of patients at the protein (hazard ratio [HR], 0.52; 95% CI, 0.29 to 0.93; p=0.024) and transcriptional level (HR, 0.80; 95% CI, 0.65 to 0.97; p=0.023) in high-grade serous ovarian cancer patients. We confirmed the association with 5-year overall survival (HR, 0.55; 95% CI, 0.38 to 0.78; p=0.0007) and also found an association with progression-free survival (HR, 0.72; 95% CI, 0.54 to 0.96; p=0.026) in a homogenous group of 388 high-stage (stages III-IV using the International Federation of Gynecology and Obstetrics staging system), optimally debulked high-grade serous ovarian cancer patients. GTF2H5-silencing induced a decrease of the half maximal inhibitory concentration upon cisplatin treatment in GTF2H5-silenced ovarian cancer cells. CONCLUSION: Low levels of GTF2H5 are associated with enhanced prognosis in high-grade serous ovarian cancer patients and may contribute to cisplatin sensitization.

Relationship between promoter methylation & tissue expression of MGMT gene in ovarian cancer.

Background & objectives: Epigenetic alterations, in addition to multiple gene abnormalities, are involved in the genesis and progression of human cancers. Aberrant methylation of CpG islands within promoter regions is associated with transcriptional inactivation of various tumour suppressor genes. O6-methyguanine-DNA methyltransferase (MGMT) is a DNA repair gene that removes mutagenic and cytotoxic adducts from the O6-position of guanine induced by alkylating agents. MGMT promoter hypermethylation and reduced expression has been found in some primary human carcinomas. We studied DNA methylation of CpG islands of the MGMT gene and its relation with MGMT protein expression in human epithelial ovarian carcinoma. Methods: A total of 88 epithelial ovarian cancer (EOC) tissue samples, 14 low malignant potential (LMP) tumours and 20 benign ovarian tissue samples were analysed for MGMT promoter methylation by nested methylation-specific polymerase chain reaction (MSP) after bisulphite modification of DNA. A subset of 64 EOC samples, 10 LMP and benign tumours and five normal ovarian tissue samples were analysed for protein expression by immunohistochemistry. Results: The methylation frequencies of the MGMT gene promoter were found to be 29.5, 28.6 and 20 per cent for EOC samples, LMP tumours and benign cases, respectively. Positive protein expression was observed in 93.8 per cent of EOC and 100 per cent in LMP, benign tumours and normal ovarian tissue samples. Promoter hypermethylation with loss of protein expression was seen only in one case of EOC. Interpretation & conclusions: Our results suggest that MGMT promoter hypermethylation does not always reflect gene expression.

Incremento en la expresión del ARNm del receptor c-Met en el cáncer gástrico / Increased expression of the c-Met receptor mRNA in gastric cancer

El cáncer gástrico es una de las patologías malignas más frecuentes en el mundo. En las últimas décadas la atención se ha centrado en posibles alteraciones de factores genéticos que incluyen la activación de proto-oncogenes y/o la inactivación de genes supresores tumorales. El producto del C-MET proto-oncogen y su ligando, el factor de crecimiento del hepatocito (HGF), han sido implicados en la proliferación y migración celular en el cáncer gástrico. En este estudio se analizó a nivel molecular la amplificación del ARNm del receptor c-Met a partir del tejido tumoral gástrico de pacientes a quienes se les practicó gastrectomías, utilizando el método del ácido guanidina-tiocianato-fenol-cloroformo, y el método semicuantitativo de la Reacción en Cadena de la Polimerasa con Transcriptasa Reversa (RT-PCR), encontrándose que los elevados niveles del ARNm del receptor c-Met en las muestras tumorales de los pacientes están relacionados con mayor invasión en la profundidad de la pared gástrica (r = 0,762, p<0,01), incremento en la metástasis a los ganglios linfáticos (r = 0,766, p<0,01), alta frecuencia en tumores pocos diferenciados o indiferenciados (r = 0,912, p<0,001), aumento en el estadiaje del cáncer gástrico (r = 0,838, p<0,001), y en la sobreexpresión por el método inmunohistoquímico (IHQ) de la estreptavidina-biotina marcada de su receptor a nivel proteico (r = 0,858, p<0,001). La amplificación del ARNm y/o la sobreexpresión a nivel proteico del receptor c-Met, pudieran ser utilizados como factores pronósticos en el cáncer gástrico.

Gastric cancer is one of the most common malignancies in the world. In the last decades, the attention has been focused in possible alterations of genetic factors that include proto-oncogene activation and/or the tumor suppressor gene inactivation. The product of the proto-oncogene c-MET and its ligand, hepatocyte growth factor (HGF), have been implicated in cell proliferation and migration in gastric cancer. In this study we analyzed at the molecular level, the amplification of c-Met receptor mRNA from gastric tumor tissue of patients who underwent gastrectomy, using the acid guanidinium-thiocyanate-phenol-chloroform method and the semiquantitative Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) method. It was found that high levels of c-Met receptor mRNA in tumor samples from patients are associated with greater depth of invasion in the gastric wall (r = 0.762, p<0.01), increase in metastases to lymph nodes (r = 0.766, p<0.01), high frequency of poorly differentiated or undifferentiated tumors (r = 0.912, p<0.001), increase in the gastric cancer staging (r = 0.838, p<0.001), and the overexpression, by the immunohistochemistry method (IHC) of the labeled streptavidin-biotin, of the c-Met receptor at the protein level (r = 0.858, p<0.001). The amplification of mRNA and/or protein level overexpression of the c-Met receptor could be used as prognostic factors in gastric cancer.

Expression of human mammaglobin and clinicopathologic correlations in breast cancer: The findings in Malaysia.

Background: Human mammaglobin (hMAG) is a secreted protein which has been detected in breast epithelial cells of mammary glands and has been used as a specific marker for breast cancer. Objectives: This study aims at studying the hMAG expression and identifying the significant predictors of hMAG expression in breast cancer tissues. Materials and Methods: The tissue samples were obtained from two major teaching hospitals in the country. They were examined by immunohistochemistry (IHC) and the hMAG expression was evaluated using an established scoring system. Results: Out of 84 breast cancer tissue samples, hMAG was expressed in 50 samples (59.6%). The expression of hMAG was found to be increased with cancer grade. The output of logistic regression model showed that hMAG was overexpressed in breast cancer samples from the first hospital (P = 0.014), but not with those from the second hospital. Conclusions: It can be concluded that hMAG may serve in the diagnosis and the assessment of progression with the increased cancer grade. The dominance in hMAG expression in samples from HUSM may correlate with ethnic, environmental or genetic factors.

Human hepatoma cell line (Hep G2) cellular response to hypothermic stress with recovery: Induction of Hsp70, Hsp60 and Hsf1 expression / Respuesta celular de línea de hepatoma humano (HepG2) al estrés hipotérmico con recuperación: Inducción de la expresión de Hsp60, Hsp70, y Hsf1

The cell response of human HepG2 cells exposed to hypothermia with rewarming was analyzed. Ultrastructural findings in hypothermic stressed cells showed swollen mitochondria, dispersed chromatin, vacuoles and ring-shape nucleolar reorganization. These changes were coupled with significative differences in the induction of Hsp60, inducible Hsp70 and monomeric Hsf1 in all treated samples, but not in Hsc 70 expression. Cellular response to hypothermia could be associated with the synergistic induction of Hsp expression.

En este trabajo se analizó la respuesta celular de células HepG2 expuestas a hipotermia con posterior recuperación. Los hallazgos ultraestructurales en células sometidas a estrés hipotérmico incluyeron mitocondrias edematizadas, núcleos picnóticos, vacuolas y reorganización nucleolar en forma de anillo. Tales cambios están relacionados con diferencias significativas en la inducción de la expresión de Hsp60, Hsp70 inducible y Hsf 1 monomérico en todas las muestras tratadas, pero no de Hsc70. La respuesta celular a la hipotermia puede ser relacionada con la inducción sinergística de las Hsp.

Regulation of protein synthesis and the role of eIF3 in cancer

Maintenance of cell homeostasis and regulation of cell proliferation depend importantly on regulating the process of protein synthesis. Many disease states arise when disregulation of protein synthesis occurs. This review focuses on mechanisms of translational control and how disregulation results in cell malignancy. Most translational controls occur during the initiation phase of protein synthesis, with the initiation factors being the major target of regulation through their phosphorylation. In particular, the recruitment of mRNAs through the m7G-cap structure and the binding of the initiator methionyl-tRNAi are frequent targets. However, translation, especially of specific mRNAs, may also be regulated by sequestration into processing bodies or stress granules, by trans-acting proteins or by microRNAs. When the process of protein synthesis is hyper-activated, weak mRNAs are translated relatively more efficiently, leading to an imbalance of cellular proteins that promotes cell proliferation and malignant transformation. This occurs, for example, when the cap-binding protein, eIF4E, is overexpressed, or when the methionyl-tRNAi-binding factor, eIF2, is too active. In addition, enhanced activity of eIF3 contributes to oncogenesis. The importance of the translation initiation factors as regulators of protein synthesis and cell proliferation makes them potential therapeutic targets for the treatment of cancer.

Expressão do P16 e do PDGFR-Beta no adenocarcinoma gástrico / Expression of P16 and PDGFR-Beta in gastric adenocarcinoma

OBJETIVO: Detectar a expressão imunoistoquímica do p16 e do PDGFR-beta no adenocarcinoma gástrico. MÉTODOS: Foram estudados 36 pacientes submetidos a cirurgia para adenocarcinoma gástrico entre 1998 e 2002 no Hospital da Santa Casa de Porto Alegre. As variáveis investigadas foram: idade, sexo, tamanho e localização do tumor, número de linfonodos dissecados, número de linfonodos metastáticos, tipo histológico, extensão da ressecção cirúrgica e estadiamento patológico. RESULTADOS: Não foi detectada expressão do PDGFR-beta nas peças cirúrgicas. Em relação ao p16, detectou-se perda de expressão menor que 10 por cento e menor que 1 por cento respectivamente em 89 por cento e 79 por cento das peças estudadas. CONCLUSÃO: Não houve correlação entre a perda de p16 e as variáveis estudadas.

OBJECTIVES: To detect immunohistochemistry expression of p16 and PDGFR-beta on gastric adenocarcinoma. METHODS: Thirty six patients submitted to surgery for gastric adenocarcinoma between 1998 and 2002 at Santa Casa de Porto Alegre Hospital have been studied. Variables investigated were: age, gender, tumour size and localization, number of dissected and metastatic nodes, histological type, surgical resection extension and pathological staging. RESULTS: No expression of PDGFR-beta has been detected on surgical specimens. Concerning to p16, loss of expression lower than 10 percent and 1 percent has been detected respectively on 89 percent and 79 percent of the specimens studied. CONCLUSION: There has been no correlation among p16 loss and variables studied.

Correlations in survivin expression with the expression of p53 and bcl-2 in invasive ductal carcinoma of the breast.

This work studied the correlations between survivin, bcl-2 and p53 in infiltrating ductal carcinoma of the breast. A total number of 382 cases were collected from 3 hospitals in northeastern Malaysia. Survivin, bcl-2 and p53 were detected by immunohistochemistry on samples prepared from tissue blocks. Significant correlations were found between tumor histological grades and tumor size and lymph node involvement. Highly significant statistical correlations (p<0.001) were found in expression of the markers under study. It is concluded that such significant correlations may imply that the alterations in the expression take place in a concerted fashion, implying that many of these cases may share common abnormalities.

Análisis de expresión global del cáncer cérvico uterino: rutas metabólicas y genes alterados / Global expression analysis in uterine cervical cancer: Metabolic pathways and altered genes

High risk human papillomavirus (HPV) infection is considered to be the most important etiological factor of Cervical Uterine Cancer. In order to determine the global expression pattern and to identify possible molecular markers of cervical cancer, cDNA arrays with probe sets complementary to 8,000 human genes were used to examine the expression profiles among 5 cell lines derived from human cervical cancer, three HPV16(+) tumor samples and three normal cervical tissues HPV(-). The levels of expression of different cellular processes were identified. Hierarchical clustering was performed and the gene expression using RT-PCR was confirmed. Two genes were found to be consistently overexpressed in invasive cervical cancer biopsies; one of them, IL-6 was previously reported to be overexpressed in cervical cancer and one novel gene, MMP10, previously not known to be related to cervical cancer. Hierarchical clustering of the expression data revealed that samples with common HPV type infection grouped together, maybe this could mean that differences between HPV types could be indirectly determined by expression profiles.

La infección por virus de papiloma de alto riesgo (VPH) es considerada como el factor etiológico más importante del cáncer cérvico uterino (CaCU). Con el fin de determinar el patrón de expresión global e identificar algunos posibles genes marcadores del CaCU, se utilizaron microhileras de DNA que contenían 8,000 secuencias que codificaban para transcritos diferentes, para estudiar los perfiles de expresión de cinco líneas celulares derivadas de CaCU, tres muestras tumorales conteniendo VPH 16 y tres muestras normales negativas para la presencia de VPH. Se identificaron los niveles de expresión de genes relacionados con diferentes rutas metabólicas. Se llevó a cabo el análisis de agrupamiento jerárquico y posteriormente se confirmó la sobrexpresión de dos genes mediante RT-PCR. Estos dos genes se encontraron sobrexpresados en biopsias tumorales cervicales. Uno de ellos, el gen de IL6, que ha sido previamente reportado en relación con CaCU, así como el gen de la matriz-metaloproteasa 10 (MMP10) por primera vez relacionado con esta neoplasia. El análisis de agrupamiento jerárquico, además, reveló que las muestras que contienen el mismo tipo viral están asociadas, sugiriendo posibles diferencias en expresión entre tipos virales.

The Proteomics Approach to Find Biomarkers in Gastric Cancer

Gastric cancer is a very serious disease and is naturally resistant to many anticancer drugs. To reduce the mortality and improve the effectiveness of therapy, many studies have tried to find key biomarkers. Proteomic technologies are providing the tools needed to discover and identify disease-associating biomarkers. The proteomic study of gastric cancer establishes any specific events that lead to cancer, and it provides a direct way to define the true function of genes. Using two dimensional (2-D) electrophoresis of the stomach cancer tissue, we have gained about 1,500 spots in each gel, and 140 protein spots also were identified. Among the identified proteins, there were seven over-expressed proteins in stomach cancer tissue: NSP3, transgelin, prohibitin, heat shock protein (hsp) 27 and variant, protein disulfide isomerase A3, unnamed protein product and glucose regulated protein. There were also seven under-expressed proteins in stomach cancer: Apolipoprotein A-1, p20, nucleoside diphosphate isomerase A, alpha 1 antitrypsin, desmin, serum albumin and sero-transferrin.

The experimental and clinical study on the effect of curcumin on cell cycle proteins and regulating proteins of apoptosis in acute myelogenous leukemia / 华中科技大学学报（医学）（英德文版）

To investigate whether the Bcl-2 gene family is involved in modulating mechanism of apoptosis and change of cell cycle protein induced by curcumin in acute myeloid leukemia HL-60 cell line and primary acute myelogenous leukemic cells, the Bcl-2 family member Mcl-1, Bax and Bak and cell cycle proteins including P27kipl, P21wafl, cyclin D3 and pRbp- were selected and their expression detected by SABC immuno-histochemical stain method. The attitude of sub-G1 peak in DNA histogram was determined by FCM. The TUNEL positive cell percentage was identified by terminal deoxynucleotidyl transferase (TdT)-mediated Biotin dUNP end labeling technique. It was found that when HL-60 cells were treated with 25 mumol/L curcumin for 24 h, the expression level of Mcl-1 was down-regulated, but that of Bax and Bak up-regulated time-dependently. There was significant difference in the expression level of Mcl-1, Bax and Bak between the curcumin-treated groups and control group (P < 0.05-0.01). At the same time, curcumin had no effect on progress of cell cycle in primaty acute myelogenous leukemia at newly diagnosis, but could increase the peak of Sub-G1 (P < 0.05), and down-regulate the expression of Mcl-1 and up-regulate the expression of Bax and Bak with the difference being statistically significant. The expression of P27kipl, P21wafl and pRbp- were elevated and that of cyclin D3 decreased in the presence of curcumin. These findings suggested that the Bcl-2 gene family indeed participated in the regulatory process of apoptosis induced by curcumin in HL-60 cells and AML cells. Curcumin can induce apoptosis of primary acute myelogenous leukemic cells and disturb cell cycle progression of HL-60 cells. The mechanism appeared to be mediated by perturbing G0/G1 phases checkpoints which associated with up-regulation of P27kipl, P21wafl and pRbp- expression, and down-regulation of cyclin D3.