Victor A. Chao

Progestins activate vascular endothelial growth factor gene transcription in endometrial adenocarcinoma cells

OBJECTIVE To determine whether progestins activate vascular endothelial growth factor (VEGF) gene transcription in endometrial adenocarcinoma cells. DESIGN In vitro study. SETTING University reproductive biology laboratories. PATIENT(S) None. INTERVENTION(S) Ishikawa cells were transfected with VEGF promoter-luciferase reporter constructs and expression vectors encoding human progesterone receptors (hPR) A or B. The cells were treated with different progestins and antiprogestins, and luciferase activity was compared with controls. MAIN OUTCOME MEASURE(S) Three functional progesterone response elements (PREs) in the VEGF promoter were identified by electrophoretic mobility-shift assay, and different constructs were created to assess each PRE. RESULT(S) In cells expressing hPRA or B, treatment with 10 nM R5020 or 100 nM medroxyprogesterone acetate statistically significantly increased luciferase activity (3.3- to 4.8-fold). Pretreatment with 100 nM RU486 blunted the effect of 10 nM R5020, resulting only in a slight, statistically nonsignificant increase in luciferase activity (1.3- to 1.7-fold). Although three different functional PREs could be identified, no single PRE accounted for the preponderance of the luciferase activity. Full VEGF promoter activation required all three PREs. CONCLUSION(S) Progestins have a direct effect on VEGF gene transcription. However, hPR-mediated transcriptional regulation of the VEGF promoter is complex and cannot be localized to confined PRE sequences. Other response element motifs are likely to play a contributory role.

Thiazolidinedione inhibition of peritoneal inflammation

Chemoattraction of macrophages into the peritoneal cavity is one of the important characteristics in patients with endometriosis. An inflammatory response is postulated to be responsible for infertility and pelvic pain associated with this syndrome. The present in vivo studies were designed to test if thiazolidinediones (TZDs), activators of peroxisome proliferator activated receptor gamma, could inhibit monocyte chemotaxis in a murine model. TZDs were first used as orally bioavailable insulin-sensitizing agents. They are currently under investigation in the treatment of inflammatory diseases, including arthritis or colitis. Intraperitoneal injection of thioglycollate was used to elicit high numbers of activated peritoneal macrophages in female mice. Concomitant peritoneal injection of ciglitazone, a member of the TZD family, significantly reduced the number of macrophages. When cultured and stimulated by tumor necrosis factor alpha, these peritoneal macrophages also secreted less RANTES and less IL-1β protein. This animal model suggests that treatment of endometriosis patients with TZDs may diminish symptoms associated with intraperitoneal inflammation.

Human umbilical vessels and cultured umbilical vein endothelial and smooth muscle cells lack detectable protein and mRNA encoding estrogen receptors.

Objective: To identify and characterize estrogen receptors in human umbilical vascular tissues and in cultured cells derived from the human umbilical vein. Methods: Human umbilical vein endothelial (HUVE) and human umbilical vein smooth muscle (HUVSM) cells were isolated. Immunohistochemical, radioligand binding, Western immunoblotting, and reverse transcription-polymerase chain reation (RT-PCR) methods were used to detect estrogen receptors in vascular tissues and in cells derived from the umbilical cord. Results: Estrogen receptor protein was not detected in either umbilical vessel tissue or in isolated HUVE or HUVSM cells. Messenger RNAs for the classic estrogen receptor (α) and estrogen receptor β isoforms also were undetectable by RT-PCR. Conclusion: These findings suggest that the effects of estradiol observed in this widely used vascular model are mediated by very low concentrations of receptors that evade standard methods of detection. Alternatively, this steroid may affect umbilical vascular cells through mechanisms that do not involve the classic genomic estrogen-receptor pathway.