Mariana Maschietto

Publications (5) View all

• Source

  Available from: Clarissa Severino Gama

  Article: Gene expression of peripheral blood lymphocytes may discriminate patients with schizophrenia from controls.

  Mariana Maschietto, Aderbal R Silva, Renato D Puga, Leandro Lima, Carlos B Pereira, Eduardo Y Nakano, Barbara Mello, Clarissa S Gama, Paulo Belmonte-de-Abreu, Dirce M Carraro, Joana A Palha, Helena Brentani
  [show abstract] [hide abstract]
  ABSTRACT: To identify a classifier in schizophrenia, blood gene expression profiling was applied to patients with schizophrenia under different treatments and to controls. Expression of six genes discriminated patients with sensitivity of 89.3% and specificity of 90%, supporting the use of peripheral blood as biological material for diagnosis in schizophrenia.
  Psychiatry Research 05/2012; · 2.52 Impact Factor
• Source

  Available from: Mariana Maschietto

  Article: Gene expression analysis of blastemal component reveals genes associated with relapse mechanism in Wilms tumour.

  Mariana Maschietto, Fabio S Piccoli, Cecilia M L Costa, Luiz P Camargo, Jose I Neves, Paul E Grundy, Helena Brentani, Fernando A Soares, Beatriz de Camargo, Dirce M Carraro
  [show abstract] [hide abstract]
  ABSTRACT: Wilms tumour (WT) is a paediatric kidney tumour, composed of blastemal, epithelial and stromal cells, with a relapse rate of approximately 15%. Long-term survival for patients with relapse remains approximately 50%. Current clinical and molecular research is directed towards identifying prognostic factors to define the minimal and intensive therapy for successful treatment of children with low and high risk of relapse, respectively. Blastemal component presents a high level of aggressiveness and responsiveness to chemotherapy. To identify molecular prognostic markers that are predictive of chemotherapy sensitivity in tumour relapse, blastemal-enriched samples from stage III and IV WT, from patients with relapse or without relapse, were analysed for 4608 human genes immobilised on a customised cDNA platform. These analyses revealed 69 differentially expressed genes, and the top nine genes were further evaluated by qRT-PCR in the initial WT samples. TSPAN3, NCOA6, CDO1, MPP2 and MCM2 were confirmed to be down-regulated in relapse WT, and TSPAN3 and NCOA6 were also validated in an independent sample group. Protein expression of MCM2 and NCOA6 were observed in 38% (13 out of 34) and 28% (9 out of 32), respectively, of independent stage III and IV WT blastema samples, without association with relapse. However, a significant association between MCM2 positive staining and chemotherapy as first treatment suggests the involvement of MCM2 with drug metabolism in WT blastemal cells.
  European journal of cancer (Oxford, England: 1990) 06/2011; 47(18):2715-22. · 4.12 Impact Factor
• Article: Evaluation of quantitative rt-PCR using nonamplified and amplified RNA.

  Elisa N Ferreira, Mariana Maschietto, Sabrina D Silva, Helena Brentani, Dirce M Carraro
  [show abstract] [hide abstract]
  ABSTRACT: Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) is a standard assay in molecular medicine for gene expression analysis. Samples from incisional/needle biopsies, laser-microdissected tumor cells and other biologic sources, normally available in clinical cancer studies, generate very small amounts of RNA that are restrictive for expression analysis. As a consequence, an RNA amplification procedure is required to assess the gene expression levels of such sample types. The reproducibility and accuracy of relative gene expression data produced by sensitive methodology as qRT-PCR when cDNA converted from amplified (A) RNA is used as template has not yet been properly addressed. In this study, to properly evaluate this issue, we performed 1 round of linear RNA amplification in 2 breast cell lines (C5.2 and HB4a) and assessed the relative expression of 34 genes using cDNA converted from both nonamplified (NA) and A RNA. Relative gene expression was obtained from beta actin or glyceraldehyde 3-phosphate dehydrogenase normalized data using different dilutions of cDNA, wherein the variability and fold-change differences in the expression of the 2 methods were compared. Our data showed that 1 round of linear RNA amplification, even with suboptimal-quality RNA, is appropriate to generate reproducible and high-fidelity qRT-PCR relative expression data that have similar confidence levels as those from NA samples. The use of cDNA that is converted from both A and NA RNA in a single qRT-PCR experiment clearly creates bias in relative gene expression data.
  Diagnostic molecular pathology: the American journal of surgical pathology, part B 03/2010; 19(1):45-53. · 1.58 Impact Factor
• Source

  Available from: Mariana Maschietto

  Article: Temporal blastemal cell gene expression analysis in the kidney reveals new Wnt and related signaling pathway genes to be essential for Wilms' tumor onset.

  M Maschietto, A P Trapé, F S Piccoli, T I Ricca, A A M Dias, R A Coudry, P A Galante, C Torres, L Fahhan, S Lourenço, P E Grundy, B de Camargo, S de Souza, E J Neves, F A Soares, H Brentani, D M Carraro
  [show abstract] [hide abstract]
  ABSTRACT: Wilms' tumors (WTs) originate from metanephric blastema cells that are unable to complete differentiation, resulting in triphasic tumors composed of epithelial, stromal and blastemal cells, with the latter harboring molecular characteristics similar to those of the earliest kidney development stages. Precise regulation of Wnt and related signaling pathways has been shown to be crucial for correct kidney differentiation. In this study, the gene expression profile of Wnt and related pathways was assessed in laser-microdissected blastemal cells in WTs and differentiated kidneys, in human and in four temporal kidney differentiation stages (i.e. E15.5, E17.5, P1.5 and P7.5) in mice, using an orthologous cDNA microarray platform. A signaling pathway-based gene signature was shared between cells of WT and of earliest kidney differentiation stages, revealing genes involved in the interruption of blastemal cell differentiation in WT. Reverse transcription-quantitative PCR showed high robustness of the microarray data demonstrating 75 and 56% agreement in the initial and independent sample sets, respectively. The protein expression of CRABP2, IGF2, GRK7, TESK1, HDGF, WNT5B, FZD2 and TIMP3 was characterized in WTs and in a panel of human fetal kidneys displaying remarkable aspects of differentiation, which was recapitulated in the tumor. Taken together, this study reveals new genes candidate for triggering WT onset and for therapeutic treatment targets.
  Cell Death & Disease 01/2011; 2:e224. · 5.33 Impact Factor
• Article: Molecular profiling of isolated histological components of wilms tumor implicates a common role for the Wnt signaling pathway in kidney and tumor development.

  Mariana Maschietto, Beatriz de Camargo, Helena Brentani, Paul Grundy, Simone T Sredni, César Torres, Louise D Mota, Isabela W Cunha, Diogo F C Patrão, Cecília M L Costa, Fernando A Soares, Ricardo R Brentani, Dirce M Carraro
  [show abstract] [hide abstract]
  ABSTRACT: Wilms tumor (WT), a tumor composed of three histological components - blastema (BL), epithelia and stroma - is considered an appropriate model system to study the biological relationship between differentiation and tumorigenesis. To investigate molecular associations between nephrogenesis and WT, the gene expression pattern of individual cellular components was analyzed, using a customized platform containing 4,608 genes. WT gene expression patterns were compared to genes regulated during kidney differentiation. BL had a closer gene expression pattern to the earliest stage of normal renal development. The BL gene expression pattern was compared to that of fetal kidney (FK) and also between FK and mature kidney, identifying 25 common deregulated genes supposedly involved in the earliest events of WT onset. Quantitative RT-PCR was performed, confirming the difference in expression levels for 13 of 16 genes (81.2%) in the initial set and 8 of 13 (61.5%) in an independent set of samples. An overrepresentation of genes belonging to the Wnt signaling pathway was identified, namely PLCG2, ROCK2 and adenomatous polyposis coli (APC). Activation of the Wnt pathway was confirmed in WT, using APC at protein level and PLCG2 at mRNA and protein level. APC showed positive nuclear immunostaining for an independent set of WT samples, similarly to the FK in week 11. Lack of PLCG2 expression was confirmed in WT and in FK until week 18. Taken together, these results provided molecular evidence of the recapitulation of the embryonic kidney by WT as well as involvement of the Wnt pathway in the earliest events of WT onset.
  Oncology 10/2008; 75(1-2):81-91. · 2.27 Impact Factor