Vascular endothelial growth factor-D over-expressing tumor cells induce differential effects on uterine vasculature in a mouse model of endometrial cancer.
BACKGROUND
It has been hypothesised that increased VEGF-D expression may be an independent prognostic factor for endometrial cancer progression and lymph node metastasis; however, the mechanism by which VEGF-D may promote disease progression in women with endometrial cancer has not been investigated. Our aim was to describe the distribution of lymphatic vessels in mouse uterus and to examine the effect of VEGF-D over-expression on these vessels in a model of endometrial cancer. We hypothesised that VEGF-D over-expression would stimulate growth of new lymphatic vessels into the endometrium, thereby contributing to cancer progression.


METHODS
We initially described the distribution of lymphatic vessels (Lyve-1, podoplanin, VEGFR-3) and VEGF-D expression in the mouse uterus during the estrous cycle, early pregnancy and in response to estradiol-17beta and progesterone using immunohistochemistry. We also examined the effects of VEGF-D over-expression on uterine vasculature by inoculating uterine horns in NOD SCID mice with control or VEGF-D-expressing 293EBNA tumor cells.


RESULTS
Lymphatic vessels positive for the lymphatic endothelial cell markers Lyve-1, podoplanin and VEGFR-3 profiles were largely restricted to the connective tissue between the myometrial circular and longitudinal muscle layers; very few lymphatic vessel profiles were observed in the endometrium. VEGF-D immunostaining was present in all uterine compartments (epithelium, stroma, myometrium), although expression was generally low. VEGF-D immunoexpression was slightly but significantly higher in estrus relative to diestrus; and in estradiol-17beta treated mice relative to vehicle or progesterone treated mice. The presence of VEGF-D over-expressing tumor cells did not induce endometrial lymphangiogenesis, although changes were observed in existing vessel profiles. For myometrial lymphatic and endometrial blood vessels, the percentage of profiles containing proliferating endothelial cells, and the cross sectional area of vessel profiles were significantly increased in response to VEGF-D in comparison to control tumor cells. In contrast, no significant changes were noted in myometrial blood vessels. In addition, examples of invading cells or tumor emboli were observed in mice receiving VEGF-D expressing 293EBNA cells.


CONCLUSIONS
These results illustrate that VEGF-D over-expression has differential effects on the uterine vasculature. These effects may facilitate VEGF-D's ability to promote endometrial cancer metastasis and disease progression.
Girling
Jane E
JE
Centre for Women's Health Research, Monash Institute of Medical Research and Monash University Department of Obstetrics and Gynaecology, Monash Medical Centre, 246 Clayton Rd, Clayton, VIC 3168, Australia. jane.girling@med.monash.edu.au
Donoghue
Jacqueline F
JF
Lederman
Fiona L
FL
Cann
Leonie M
LM
Achen
Marc G
MG
Stacker
Steven A
SA
Rogers
Peter Aw
PA
D000818:Animals; D018269:Carcinoma, Endometrioid / Q000098:blood supply / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002478:Cells, Cultured; D004195:Disease Models, Animal; D016889:Endometrial Neoplasms / Q000098:blood supply / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D008822:Mice, Transgenic; D014183:Transplantation, Heterologous; D015854:Up-Regulation / Q000235:genetics; D014599:Uterus / Q000098:blood supply* / Q000378:metabolism / Q000473:pathology; D042643:Vascular Endothelial Growth Factor D / Q000235:genetics*
D042643:Vascular Endothelial Growth Factor D