Complexity of VEGF responses in skin carcinogenesis revealed through ex vivo assays based on a VEGF-A null mouse keratinocyte cell line.
Vascular endothelial growth factor (VEGF-A) is a critical player in cutaneous angiogenesis. However, the relative contribution of VEGF-A from different sources including epithelial and mesenchymal cells has not been fully characterized during skin repair and tumorigenesis. Moreover, the actual involvement of other vascular-specific acting molecules has remained elusive in part due to the masking and/or overlapping effects of VEGF-A. To shed light on these uncertainties we generated and characterized a clonal VEGF-null mouse keratinocyte cell line, through in vitro adenoviral gene transfer of Cre recombinase to VEGF-LoxP primary keratinocytes followed by repeated cell passaging under controlled conditions and cloning. In vitro and in vivo assays demonstrated that VEGF-null keratinocytes were nontumorigenic and expressed normal differentiation markers after calcium switch. Hras-induced tumorigenesis of immortalized VEGF-null keratinocytes upon subcutaneous injection was markedly reduced but not fully suppressed. However, the metastatic ability of Hras-transformed VEGF-null keratinocytes was abolished. These ex vivo approaches suggest the existence of VEGF-dependent and independent angiogenic stimuli in skin carcinogenesis. The VEGF-null mouse keratinocyte cell line arises as an important tool to assess the actual contribution of keratinocyte-derived VEGF with respect to other angiogenic factors in skin homeostasis and malignancy.
Mirones
Isabel
I
Cutaneous Disease Modelling Unit, Epithelial Biomedicine Division, Basic Research Department, CIEMAT-CIBERER, Madrid, Spain.
Conti
Claudio J
CJ
Martínez
Jesús
J
Garcia
Marta
M
Larcher
Fernando
F
D000256:Adenoviridae / Q000235:genetics; D000483:Alleles; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D018014:Gene Transfer Techniques; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D009362:Neoplasm Metastasis; D009389:Neovascularization, Pathologic; D012867:Skin / Q000378:metabolism; D012878:Skin Neoplasms / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D018631:ras Proteins / Q000378:metabolism
D042461:Vascular Endothelial Growth Factor A; D018631:ras Proteins; D002118:Calcium