Glycan profiling using formalin-fixed, paraffin-embedded tissues: Hippeastrum hybrid lectin is a sensitive biomarker for squamous cell carcinoma of the uterine cervix.

AIM: Glycosylation of proteins is altered in cancer cells and distinctive glycan structures are associated with specific cancers, but little is known about the complete glycan profile of particular tumors. In this study, glycomic analysis of squamous cell carcinoma (SCC) of the uterine cervix was performed to search for useful markers. METHODS: A lectin microarray containing 45 lectins with different binding preferences that covered N- and O-linked glycans was coupled with evanescent field-activated fluorescent detection for glycomic analysis of SCC and normal squamous epithelium (NSE) of the cervix. Formalin-fixed, paraffin-embedded tissue specimens were obtained from 16 patients with uterine cervical cancer. Sections that included both tumor and non-tumor tissues were examined to detect alterations of glycans based on the lectin-binding pattern. RESULTS: Hippeastrum hybrid lectin was found to be a sensitive marker for distinguishing SCC of the cervix from NSE. It was the best lectin for discriminating SCC from other tissues according to receiver-operator curve analysis, as it showed a high sensitivity (81.8%), a high specificity (70.1%), and a large area under the curve (0.8182). Histochemistry confirmed specific cytoplasmic staining of SCC cells by Hippeastrum hybrid lectin, while there was little staining of cervical intraepithelial neoplasia and no staining of NSE. CONCLUSION: The present lectin microarray technique could be applied for tissue-based glycomic analysis of various tumors and for discovery of glycan-related biomarkers.

NLRP5 mediates mitochondrial function in mouse oocytes and embryos.

Unraveling molecular pathways responsible for regulation of early embryonic development is crucial for our understanding of female infertility. Maternal determinants that control the transition from oocyte to embryo are crucial molecules that govern developmental competence of the newly conceived zygote. We describe a series of defects that are triggered by a disruption of maternal lethal effect gene, Nlrp5. Previous studies have shown that Nlrp5 hypomorph embryos fail to develop beyond the two-cell stage. Despite its importance in preimplantation development, the mechanism by which the embryo arrest occurs remains unclear. We confirmed that Nlrp5 mutant and wild-type females possess comparable ovarian germ pool and follicular recruitment rates. However, ovulated oocytes lacking Nlrp5 have abnormal mitochondrial localization and increased activity in order to sustain physiological ATP content. This results in an accumulation of reactive oxygen species and increased cellular stress causing mitochondrial depletion. Compromised cellular state is also accompanied by increased expression of cell death inducer Bax and depletion of cytochrome c. However, neither genetic deletion (Bax/Nlrp5 double knockout) nor mimetic interference (BH4 domain or Bax inhibitory peptide) were sufficient to alleviate embryo demise caused by depletion of Nlrp5. We therefore conclude that lack of Nlrp5 in oocytes triggers premature activation of the mitochondrial pool, causing mitochondrial damage that cannot be rescued by inactivation of Bax.

TAp73 regulates the spindle assembly checkpoint by modulating BubR1 activity.

The role of various p73 isoforms in tumorigenesis has been controversial. However, as we have recently shown, the generation of TAp73-deficient (TAp73(-/-)) mice reveals that TAp73 isoforms exert tumor-suppressive functions, indicating an emerging role for Trp-73 in the maintenance of genomic stability. Unlike mice lacking all p73 isoforms, TAp73(-/-) mice show a high incidence of spontaneous tumors. Moreover, TAp73(-/-) mice are infertile and produce oocytes exhibiting spindle abnormalities. These data suggest a link between TAp73 activities and the common molecular machinery underlying meiosis and mitosis. Previous studies have indicated that the spindle assembly checkpoint (SAC) complex, whose activation leads to mitotic arrest, also regulates meiosis. In this study, we demonstrate in murine and human cells that TAp73 is able to interact directly with several partners of the SAC complex (Bub1, Bub3, and BubR1). We also show that TAp73 is involved in SAC protein localization and activities. Moreover, we show that decreased TAp73 expression correlates with increases of SAC protein expression in patients with lung cancer. Our results establish TAp73 as a regulator of SAC responses and indicate that TAp73 loss can lead to mitotic arrest defects. Our data suggest that SAC impairment in the absence of functional TAp73 could explain the genomic instability and increased aneuploidy observed in TAp73-deficient cells.