RESUMEN
Cleft lip and/or palate (CL/P) is a common congenital malformation with a complex etiology which is not fully elucidated yet. Epidemiological studies point to different etiologies in the cleft lip and palate subgroups, isolated cleft lip (CL), isolated cleft palate (CP) and combined cleft lip and palate (CLP). In order to understand the biological basis in these cleft lip and palate subgroups better we studied the expression profiles in human tissue from patients with CL/P. In each of the CL/P subgroups, samples were obtained from three patients and gene expression analysis was performed. Moreover, selected differentially expressed genes were analyzed by quantitative RT-PCR, and by immunohistochemical staining of craniofacial tissue from human embryos. Osteopontin (SPP1) and other immune related genes were significantly higher expressed in palate tissue from patients with CLP compared to CP and immunostaining in palatal shelves against SPP1, chemokine receptor 4 (CXCR4) and serglycin (PRG1) in human embryonic craniofacial tissue were positive, supporting a role for these genes in palatal development. However, gene expression profiles are subject to variations during growth and therefore we recommend that future gene expression in CL/P studies should use tissue from the correct embryonic time and place if possible, to overcome the biases in the presented study.
Asunto(s)
Labio Leporino/genética , Labio Leporino/inmunología , Fisura del Paladar/genética , Fisura del Paladar/inmunología , Osteopontina/genética , Fisura del Paladar/embriología , Perfilación de la Expresión Génica , Humanos , Inmunohistoquímica , Lactante , Análisis de Secuencia por Matrices de Oligonucleótidos , Osteopontina/inmunología , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Hedgehog (HH) signaling plays a critical role during embryogenesis and regulates early development of multiple tissues and organs, including the central nervous system. Although much has been revealed of the diverse functions of the HH signaling pathway, it is still unclear how the effects of altered HH signaling are interpreted by specific cell types. We have investigated the role of the HH transcription factor glioma-associated oncogene homolog 1 (GLI1) in the human Ntera2/D1 (NT2) embryonal carcinoma stem cell line. The study revealed that expression of GLI1 and its direct transcriptional target Patched (PTCH) is downregulated in the early stages of retinoic acid-induced neuronal differentiation of NT2 cells. To identify transcriptional targets of the HH transcription factor GLI1 in NT2 cells, we performed global expression profiling following GLI1 RNA interference (RNAi). Of the 8500 transcripts represented on the microarrays, expression of 88 genes was downregulated and expression of 26 genes was upregulated. Nineteen of these genes are involved in cell cycle and proliferation. Further, GLI1 RNAi leads to a significant decrease in NT2 proliferation and changes expression of G1 phase cyclins. In conclusion, our results suggest that GLI1 is involved in cell cycle and proliferation control in the embryonal carcinoma stem cell line NT2.
Asunto(s)
Biomarcadores de Tumor/metabolismo , Proliferación Celular , Células Madre de Carcinoma Embrionario/metabolismo , Fase G1/fisiología , Factores de Transcripción/fisiología , Biomarcadores de Tumor/genética , Diferenciación Celular , Células Madre de Carcinoma Embrionario/patología , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Proteínas Hedgehog/metabolismo , Humanos , Análisis de Secuencia por Matrices de Oligonucleótidos , ARN Interferente Pequeño/farmacología , Transducción de Señal , Transcripción Genética , Tretinoina/farmacología , Proteína con Dedos de Zinc GLI1RESUMEN
The hedgehog (HH) signaling pathway plays multiple roles during embryonic development and increasing evidence suggests that this embryonic pathway is involved in development and progression of several human cancers including those of the brain, skin, lung and gastrointestinal tract. To investigate HH signaling activity in small-cell lung cancer (SCLC), we have performed gene expression analysis on members of the HH pathway on a panel of 20 SCLC cell lines. Sonic hedgehog (SHH) expression was detected in only DMS79 and GLC16 and only DMS114 expressed detectable protein levels of GLI1, one of the key transcription factors of the pathway. Involvement of HH signaling in SCLC proliferation was investigated in a subset of cell lines using the HH signaling inhibitor cyclopamine or small interfering RNA (siRNA) against GLI1. Cells expressing GLI1 responded only weakly to both cyclopamine and RNA interference, suggesting that HH signaling plays only a minor role in the growth of SCLC cell lines. To investigate HH pathway activity in vivo, GLI1 immunohistochemistry was performed on SCLC tumors. Interestingly, GLI1 was expressed in most SCLC tumors studied, indicating that HH signaling is important for in vivo growth of SCLC but establishment of cell lines from SCLC tumors may lead to loss of expression of key HH pathway members. Thus, the data support the idea that the HH pathway may be a therapeutic target in SCLC. However, the data also suggest that the SCLC cells can circumvent the apparent in vivo requirement of HH signaling.