RESUMEN
Chromosome 4p15.3 is frequently deleted in late-stage lung cancer. We investigated the significance of the SLIT2 gene located in this region to lung cancer progression. SLIT2 encodes an extracellular glycoprotein that can suppress breast cancer by regulating beta-catenin. In this study, we examined alterations in the structure or expression of SLIT2, its receptor ROBO1, and beta-catenin, along with the AKT/glycogen synthase kinase 3beta (GSK3beta)/beta-transducin repeat-containing protein (betaTrCP) pathway in lung cancer cell lines and patients. Low SLIT2 expression correlated with an upward trend of pathological stage and poorer survival in lung cancer patients. Importantly, SLIT2, betaTrCP, and beta-catenin expression levels predicted postoperative recurrence of lung cancer in patients. Stimulating SLIT2 expression by various methods increased the level of E-cadherin caused by attenuation of its transcriptional repressor SNAI1. Conversely, knocking down SLIT2 expression increased cell migration and reduced cell adhesion through coordinated deregulation of beta-catenin and E-cadherin/SNAI1 in the AKT/GSK3beta/betaTrCP pathway. Our findings indicate that SLIT2 suppresses lung cancer progression, defining it as a novel "theranostic" factor with potential as a therapeutic target and prognostic predictor in lung cancer. Cancer Res; 70(2); 543-51.
Asunto(s)
Cadherinas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Neoplasias Pulmonares/metabolismo , Proteínas del Tejido Nervioso/metabolismo , beta Catenina/metabolismo , Azacitidina/análogos & derivados , Azacitidina/farmacología , Carcinoma de Pulmón de Células no Pequeñas/patología , Movimiento Celular/fisiología , Metilación de ADN , Decitabina , Progresión de la Enfermedad , Técnicas de Silenciamiento del Gen , Glucógeno Sintasa Quinasa 3/metabolismo , Glucógeno Sintasa Quinasa 3 beta , Humanos , Inmunohistoquímica , Péptidos y Proteínas de Señalización Intercelular/biosíntesis , Péptidos y Proteínas de Señalización Intercelular/genética , Neoplasias Pulmonares/patología , Proteínas del Tejido Nervioso/biosíntesis , Proteínas del Tejido Nervioso/genética , Proteína Oncogénica v-akt/metabolismo , Pronóstico , Regiones Promotoras Genéticas , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Receptores Inmunológicos/biosíntesis , Receptores Inmunológicos/genética , Receptores Inmunológicos/metabolismo , Proteínas con Repetición de beta-Transducina/metabolismo , Proteínas RoundaboutRESUMEN
BACKGROUND: M-phase promoting factor (MPF), which is comprised of Cyclin B and a catalytic subunit, Cdc2, is a key enzyme required for cells to enter M phase in both mitosis and meiosis. MPF activity is controlled by the stimulatory dephosphorylation of the Cdc25 family and the inhibitory phosphorylation of Wee1. We determined the levels of mRNA transcripts of MPF and its regulators in the testes of infertile men, and evaluated the relationship between the transcript levels and patients' testicular phenotypes and sperm retrieval results. METHODS AND RESULTS: The mRNA transcript levels of CDC2, CCNB1, CCNB2, CDC25A, CDC25B, CDC25C and WEE1 in the testes of 37 azoospermic patients were examined by quantitative real-time polymerase chain reaction. Significant decreases in CDC2, CCNB1, CCNB2, CDC25A, CDC25C and WEE1 mRNA transcript levels were detected in patients with spermatogenic failure. CDC2 mRNA transcript levels correlated significantly with those of CCNB1 and CCNB2 mRNA. Significantly higher CDC2, CCNB1, CCNB2, CDC25C and WEE1 mRNA transcript levels were detected in 18 patients with successful sperm retrieval than in 11 patients with failed sperm retrieval. CONCLUSIONS: We suggest that the decreased mRNA transcripts of MPF and its regulators play important roles in human spermatogenesis.
Asunto(s)
Regulación hacia Abajo , Regulación de la Expresión Génica , Infertilidad Masculina/genética , Factor Promotor de Maduración/genética , Testículo/metabolismo , Adulto , Proteínas de Ciclo Celular/genética , Humanos , Masculino , Proteínas Tirosina Quinasas/genética , ARN Mensajero/análisis , ARN Mensajero/metabolismo , Espermatogénesis/genética , Testículo/química , Transcripción Genética , Fosfatasas cdc25/genéticaRESUMEN
Single-strand conformation polymorphism analysis of exon-containing genomic DNA segments of the deleted-in-azoospermia-like (DAZL) gene was performed in 160 infertile Taiwanese men presenting with severe oligozoospermia and nonobstructive azoospermia. An A-->G transition at nucleotide 386 in exon 3 was identified. The mutation is located within the RNA-recognition motif (aa 32-117) domain of the DAZL protein and will lead to Thr54-->Ala change (T54A) of DAZL protein. Analysis of cDNA from testicular tissue of infertile carriers showed absence of expression for the T54A allele, implying that the allele carrying T54A polymorphism is hardly, if ever, expressed. The frequencies of T54A allele in patients and the control group were 7.39% and 0.86%, respectively (P = 0.0003). The phenotypes varied significantly in cases with heterozygous T54A polymorphism, ranging from hypospermatogenesis and maturation arrest to Sertoli cell-only syndrome. A combination of DAZ gene deletion and T54A polymorphism did not worsen the phenotype. Our findings provide strong evidence for the role of the autosomal DAZL gene in human spermatogenesis.