Identification and Localization of Alternately Spliced mRNAs for Vascular Endothelial Growth Factor in Human Uterus and Estrogen Regulation in Endometrial Carcinoma Cell Lines1

Abstract

Repair of human endometrium after menstruation and preparation of the endometrium for implantation involves profound angiogenic changes. Vascular endothelial cell growth factor (VEGF) is a recently identified growth factor with significant angiogenic properties. Four species of mRNA encoding VEGFs were identified in human endometrium and myometrium. All species were present throughout the menstrual cycle. Two species, VEGF165 and VEGF121, were present in peripheral leukocytes, indicating tissue-specific splicing of the two other VEGF transcripts. In situ hybridization of mRNA encoding VEGF was not restricted to vascular smooth muscle but was present in epithelial and stromal cells of endometrium throughout the cycle, and the distribution changed during the course of the cycle. All four species of VEGF were expressed by the endometrial carcinoma cell lines Ishikawa, HEC 1-A, and HEC 1-B. Estradiol increased steady-state levels of mRNA encoding VEGF in a dose- and time-dependent manner in HEC 1-A cells. Conditioned medium from these cells possessed angiogenic activity that was depleted by passage through a heparin affinity column. None of the cell lines demonstrated mRNA for acidic or basic fibroblast growth factor (FGF), despite previous reports of the identification of immunoreactive basic FGF in HEC 1-A and HEC 1-B cells. These findings show that VEGFs, not FGFs, are the principal angiogenic growth factors secreted by these cells and that human endometrium expresses a secreted angiogenic growth factor whose site of expression changes during the menstrual cycle.

A dynamic shift of VEGF isoforms with a transient and selective progesterone-induced expression of VEGF189regulates angiogenesis and vascular permeability in human uterus

“…This result extends previous reports showing that V 121 and V 165 are the predominant forms produced at the mRNA level in the uterus (3,5,7). Consistent with our in situ observations, relative expression levels of immunoreactive VEGF isoforms and specific V 189 increase in perivascular stromal cells during the same period, in contrast to the diffuse staining in the stroma observed in proliferative and early-mid secretory endometrium (5-7); the difference between faint stromal staining and presence of VEGF transcripts in stromal cells during the menstrual cycle was initially interpreted to be a consequence of differences in the sensitivity between immunocytochemistry (ICC) and RT-PCR analysis or in situ hybridization.…”

“…Although previous studies have shown that E 2 regulates the expression of all VEGF transcripts in endometrial cells (3)(4)(5)(6)(7)20), the expression and modulation of VEGF isoforms during human implantation and decidualization is not yet elucidated. The present study demonstrates considerable expression of the V 189 isoform in the human endometrium (functional layer) during the mid-late secretory phase.…”

“…A s a tissue that exhibits rapid cyclic changes (1), the human endometrium is a good model for the study of physiological angiogenesis, which is under the control of 17␤ estradiol (E 2 ), progesterone (P), and vascular endothelial growth factor (VEGF) (2)(3)(4)(5)(6)(7).…”

Angiogenic role for glycodelin in tumorigenesis

“…VEGF145 has been detected as a rare VEGF mRNA species in placenta (35,36) and in several tumorigenic cell types that originated from the female reproductive system (37). VEGF121, VEGF145, and VEGF165 are secreted in the medium by cells, whereas VEGF189 and VEGF206 are sequestered by cell-surface heparin sulfates (38).…”

Vascularization of the mouse embryo: A study of flk‐1, tek, tie, and vascular endothelial growth factor expression during development

“…Assuming that Flt-1 is a bonafide receptor for VEGF, the expression of these three genes in the placenta establishes a very interesting paradigm. The VEGF gene is known to produce five different isoforms of VEGF by differential splicing (Houck et al, 1991a,b;Breier et al, 1992;Neufeld et al, 1994;Tischer et al, 1991;Charnock-Jones et al, 1993) and the probe used in these studies detects all 5 isoforms. The two largest isoforms are thought to re-main either cell-or extra-cellular matrix associated, whereas the three smaller isoforms exist as free polypeptides (Houck et al, 1991a).…”