Expression, mutation and copy number analysis of platelet-derived growth factor receptor A (PDGFRA) and its ligand PDGFA in gliomas

BACKGROUND

Malignant gliomas are the most prevalent type of primary brain tumours but the therapeutic armamentarium for these tumours is limited. Platelet-derived growth factor (PDGF) signalling has been shown to be a key regulator of glioma development. Clinical trials evaluating the efficacy of anti-PDGFRA therapies on gliomas are ongoing. In this study, we intended to analyse the expression of PDGFA and its receptor PDGFRA, as well as the underlying genetic (mutations and amplification) mechanisms driving their expression in a large series of human gliomas.

METHODS

PDGFA and PDGFRA expression was evaluated by immunohistochemistry in a series of 160 gliomas of distinct World Health Organization (WHO) malignancy grade. PDGFRA-activating gene mutations (exons 12, 18 and 23) were assessed in a subset of 86 cases by PCR-single-strand conformational polymorphism (PCR-SSCP), followed by direct sequencing. PDGFRA gene amplification analysis was performed in 57 cases by quantitative real-time PCR (QPCR) and further validated in a subset of cases by chromogenic in situ hybridisation (CISH) and microarray-based comparative genomic hybridisation (aCGH).

RESULTS

PDGFA and PDGFRA expression was found in 81.2% (130 out of 160) and 29.6% (48 out of 160) of gliomas, respectively. Its expression was significantly correlated with histological type of the tumours; however, no significant association between the expression of the ligand and its receptor was observed. The absence of PDGFA expression was significantly associated with the age of patients and with poor prognosis. Although PDGFRA gene-activating mutations were not found, PDGFRA gene amplification was observed in 21.1% (12 out of 57) of gliomas. No association was found between the presence of PDGFRA gene amplification and expression, excepting for grade II diffuse astrocytomas.

CONCLUSION

The concurrent expression of PDGFA and PDGFRA in different subtypes of gliomas, reinforce the recognised significance of this signalling pathway in gliomas. PDGFRA gene amplification rather than gene mutation may be the underlying genetic mechanism driving PDGFRA overexpression in a portion of gliomas. Taken together, our results could provide in the future a molecular basis for PDGFRA-targeted therapies in gliomas.

Distinct gender-related sleep pattern in an acute model of TMJ pain

Since it is recognized that acute inflammation of the temporomandibular joint results in sleep disturbances in male rats, and that the orofacial region may display a site-specific effect of ovarian hormones on nociception, we hypothesized that distinct genders would respond differently when subjected to this inflammatory acute orofacial pain. Sleep was monitored after injection of saline/Freund's adjuvant into the temporomandibular joint in male and female (proestrus and diestrus phases) rats. Progesterone and stress-related hormones were also assessed. In males, Freund's adjuvant induced a significant nociceptive response and sleep disturbances. Behavior and sleep architecture in the females remained unaffected. Our results suggest that females and males present distinct responses to an acute model of orofacial pain.

PREVALÊNCIA DE ANTICORPOS CONTRA AGENTES VIRAIS EM EQUÍDEOS NO SUL DO ESTADO DE SÃO PAULO

RESUMO Foram analisados soros de 163 equídeos (143 equinos e 20 muares) provenientes de 16 municípios do sul do Estado de São Paulo, parte no Vale do Ribeira e parte no litoral. Utilizouse uma amostra probabilística estratificada em dois estágios, sendo a unidade amostral de primeiro estágio constituída pela unidade de produção agropecuária (UPA) e a de segundo estágio pelo animal dentro da UPA sorteada. Os soros foram coletados no período de outubro de 2004 a junho de 2005. Foram estimadas as prevalências de anticorpos contra os vírus das encefalites equinas do tipo leste (EEE), oeste (WEE) e venezuelana (VEE), herpesvírus equino (HVE), arterite viral dos equinos (AVE), influenza equina 1 e 2 (IE-1 e 2) e estomatite vesicular Indiana 2 – Cocal (COCV) e Indiana 3 – Alagoas (VSAV). Foram utilizadas as técnicas de inibição da hemoaglutinação para a detecção de anticorpos contra os vírus IE-1 e 2 e de soroneutralização para os demais vírus estudados. Dos animais testados, 26% apresentaram anticorpos contra o HVE, 21% para COCV, 5% para VSAV, 16% para EEE, 2,26% para VEE, 11% para influenza Equi/2 e 2,7% para influenza Equi/1. Não se encontraram animais reagentes para WEE e AVE. A soroprevalência obtida sugere a circulação do HVE, dos vírus da IE Equi-1(H7N7) e Equi-2 (H3N8), dos vírus EEE e VEE e dos vírus da estomatite vesicular Indiana 2 – Cocal (COCV) e Indiana 3 – Alagoas (VSAV) no rebanho de equídeos do sul do Estado de São Paulo.

Distinct effects of acute and chronic sleep loss on DNA damage in rats

The aim of this investigation was to evaluate genetic damage induced in male rats by experimental sleep loss for short-term (24 and 96 h) and long-term (21 days) intervals, as well as their respective recovery periods in peripheral blood, brain, liver and heart tissue by the single cell gel (comet) assay. Rats were paradoxically deprived of sleep (PSD) by the platform technique for 24 or 96 h, or chronically sleep-restricted (SR) for 21 days. We also sought to verify the time course of their recovery after 24 h of rebound sleep. The results showed DNA damage in blood cells of rats submitted to PSD for 96 h. Brain tissue showed extensive genotoxic damage in PSD rats (both 24 and 96 h), though the effect was more pronounced in the 96 h group. Rats allowed to recover from the PSD-96 h and SR-21 days treatments showed DNA damage as compared to negative controls. Liver and heart did not display any genotoxicity activity. Corticosterone concentrations were increased after PSD (24 and 96 h) relative to control rats, whereas these levels were unaffected in the SR group. Collectively, these findings reveal that sleep loss was able to induce genetic damage in blood and brain cells, especially following acute exposure. Since DNA damage is an important step in events leading to genomic instability, this study represents a relevant contribution to the understanding of the potential health risks associated with sleep deprivation.

Association of the polymorphisms CYP19 (TTTA)n in treatment response to hormone therapy based in aromatase inhibitors in breast cancer patients

Abstract #3033

Background 
 Case-control studies have reported inconsistent results concerning breast cancer risk and polymorphisms in genes that control endogenous estrogen biosynthesis. We report findings from the first study in Mexican women examining associations between female with breast cancer and polymorphisms CYP19 (TTTA repeated polymorphism).
 Methods 
 We conducted a study among 180 healthy women and 70 women with breast cancer underwent hormone therapy with aromatase inhibitor. DNA and questionnaire data was obtained. Tandem repeated (TTTA)n polymorphism in CYP19 gene was determined by PCR followed by electrophoresis on denaturalizing acrilamide gel stained with silver nitrate. Differences were visualized with Gel-Doc BioRad. Estrone, estradiol and FSH levels were measured by RIA and IRMA. We used likelihood-based statistical methods to examine allelic associations.
 Results:
 250 women (age 55 ± 12 years) were included. BMI was 30 ± 7.1 Kg/m2. We found a distribution of different CYP19 allele frequencies. In healthy women the allele frequencies with 6 (32.7 %) and 7 (21.6 %) tandem repetitions were the most frequent, in women with breast cancer the alleles with 6(29%) and 10(26%) tandem repeated were the most frequent. A relationship between hormonal levels and number of (TTTA) repeated was not found. Anastrozol reduced significantly estrona and estradiol. Surpriseling we found in a patients with 10 or more (TTTA)n repeated an association with a mayor tumoral activity (p=0.04).
 Conclusion 
 This study indicates that status of CYP19 >10 TTTA repeated might be related to increased breast cancer risk and with the clinical response (aromatase inhibitor). Because of this is the first study to report an association between CYP19 >10 TTTA repeated and treatment hormonal response in breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3033.