Biomedical subjects

Lidia Perez

Publications and source records attributed to Lidia Perez.

3 recordsLinked to original sources

PubMed2006

Elevated serum levels of vascular endothelial growth factor are associated with tumor-associated macrophages in primary breast cancer.

We analyzed serum and tumor samples from 133 patients with operable primary breast cancer to determine the possible relationship between presurgery and postsurgery circulating serum vascular endothelial growth factor (VEGF) levels and tumor-associated macrophage (TAM) numbers, tumor VEGF expression, and other immunohistochemical parameters. A significant positive correlation was observed between the number of TAM and postsurgery circulating VEGF values (P < .05). Moreover, patients with a p53+ tumor had higher postsurgery serum VEGF levels than those with a p53- tumor (P < .05), and tumor p53 overexpression correlated significantly with TAM number (P = .007). We observed no significant association between serum values and tumor VEGF expression. Although the macrophage index was higher in VEGF+ than in VEGF- tumors, the differences were not statistically significant. Our data show a positive interrelation between high circulating VEGF levels, the number of TAM, and p53 overexpression, a relationship that might have an important role in the enhanced angiogenesis processes in breast cancer.

Adult↗

PubMed2004

Opposing activities of Dally-like glypican at high and low levels of Wingless morphogen activity.

The glypican family of heparan sulfate proteoglycans has been implicated in formation of morphogen gradients. Here, we examine the role of the glypican Dally-like protein (Dlp) in shaping the Wingless gradient in the Drosophila wing disc. Surprisingly, we find that Dlp has opposite effects at high and low levels of Wingless. Dlp promotes low-level Wingless activity but reduces high-level Wingless activity. We present evidence that the Wg antagonist Notum acts to induce cleavage of the Dlp glypican at the level of its GPI anchor, which leads to shedding of Dlp. Thus, spatially regulated modification of Dlp by Notum employs the ligand binding activity of Dlp to promote or inhibit signaling in a context-dependent manner. Notum-induced shedding of Dlp could convert Dlp from a membrane-tethered coreceptor to a secreted antagonist.

Animals↗

PubMed2003

Multipotent cell lineages in early mouse development depend on SOX2 function.

Each cell lineage specified in the preimplantation mammalian embryo depends on intrinsic factors for its development, but there is also mutual interdependence between them. OCT4 is required for the ICM/epiblast lineage, and at transient high levels for extraembryonic endoderm, but also indirectly through its role in regulating Fgf4 expression, for the establishment and proliferation of extraembryonic ectoderm from polar trophectoderm. The transcription factor SOX2 has also been implicated in the regulation of Fgf4 expression. We have used gene targeting to inactivate Sox2, examining the phenotypic consequences in mutant embryos and in chimeras in which the epiblast is rescued with wild-type ES cells. We find a cell-autonomous requirement for the gene in both epiblast and extraembryonic ectoderm, the multipotent precursors of all embryonic and trophoblast cell types, respectively. However, an earlier role within the ICM may be masked by the persistence of maternal protein, whereas the lack of SOX2 only becomes critical in the chorion after 7.5 days postcoitum. Our data suggest that maternal components could be involved in establishing early cell fate decisions and that a combinatorial code, requiring SOX2 and OCT4, specifies the first three lineages present at implantation.

Animals↗