Origin and evolution of somatic cell testicular tumours in transgenic mice

QUINTANA S.; VENARA M.; REY R.; DI CLEMENTE N.; CHEMES H.E.

JOURNAL OF PATHOLOGY

JOHN WILEY & SONS LTD

Año: 2010 vol. 221 p. 443 - 451

0022-3417

ORIGINAL PAPER Journal of Pathology J Pathol 2010; 221: 443–451 Published online 7 June 2010 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/path.27312010; 221: 443–451 Published online 7 June 2010 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/path.2731DOI: 10.1002/path.2731 Origin and evolution of somatic cell testicular tumours in transgenic mice Silvina Quintana,1 Marcela Venara,1 Rodolfo Rey,1,2 Nathalie di Clemente3 and H´ector E Chemes1*1 Marcela Venara,1 Rodolfo Rey,1,2 Nathalie di Clemente3 and H´ector E Chemes1* 1 Center for Research in Endocrinology (CEDIE-CONICET), Buenos Aires Children’s Hospital, Gallo 1330, C1425EFD, Buenos Aires, ArgentinaCenter for Research in Endocrinology (CEDIE-CONICET), Buenos Aires Children’s Hospital, Gallo 1330, C1425EFD, Buenos Aires, Argentina 2 Department of Histology, Cell Biology, Embryology and Genetics, School of Medicine, University of Buenos Aires, Buenos Aires, ArgentinaDepartment of Histology, Cell Biology, Embryology and Genetics, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina 3 Endocrinologie et G´en´etique de la Reproduction et du D´eveloppement. Unit´e INSERM 782, 32 Rue des Carnets, Clamart, F-92140; Univ. Paris-Sud, UMR-S0782, Clamart, F-92140, France *Correspondence to: H´ector E Chemes, Center for Research in Endocrinology (CEDIE-CONICET), Buenos Aires Children’s Hospital, Gallo 1330, C1425EFD, Buenos Aires, Argentina e-mail: hchemes@cedie.org.arEndocrinologie et G´en´etique de la Reproduction et du D´eveloppement. Unit´e INSERM 782, 32 Rue des Carnets, Clamart, F-92140; Univ. Paris-Sud, UMR-S0782, Clamart, F-92140, France *Correspondence to: H´ector E Chemes, Center for Research in Endocrinology (CEDIE-CONICET), Buenos Aires Children’s Hospital, Gallo 1330, C1425EFD, Buenos Aires, Argentina e-mail: hchemes@cedie.org.ar Abstract Transgenic mice bearing a construct in which the expression of the SV40 oncogene is directed by the AMH promoter (AT mice) develop testicular tumours in adult life. We aimed to study early steps of tumour development and characterize tumours at different ages by histological, morphometric, and immunohistochemical techniques. One- to 3-month-old AT mice depicted multifocal Leydig cell hyperplasia. The testicular volume occupied by interstitial tissue was significantly higher in 3-month-old AT mice in comparison with littermate controls. Between 5 1/2 and 7 months, microscopic interstitial tumours developed that progressively evolved to form large confluent areas of high mitotic index in 7- to 14-month-old AT mice. Tumour cells had the characteristics and histoarchitecture of Leydig cells, or formed solid cord-like structures reminiscent of those seen in Sertoli cell tumours. Hyperplastic areas and tumours diffusely expressed 3β-hydroxysteroid dehydrogenase (3β-HSD) in Leydig cell areas. AMH expression was negative in Leydig cell conglomerates and tumours and variable in cord-like tumours. The SV40 T antigen and markers of cell proliferation (PCNA) were intensely positive in hyperplastic cells and tumours. Control mice of similar ages showed neither hyperplasia nor tumours, and SV40 T expression was always negative. In conclusion, transgenic mice develop large testicular tumours that are preceded by interstitial hyperplasia and microtumours. The histological and immunohistochemical phenotype of tumours (Leydig and Sertoli cell differentiation, positive 3β-HSD, and variable AMH) suggests a mixed differentiation of somatic cells of the specialized gonadal stroma. The finding that an oncogene directed by a promoter specifically active in fetal Sertoli cells has given rise to testicular tumours of mixed differentiation is compatible with a common origin of Leydig and Sertoli cells from the specific stroma of the gonadal ridge, as supported by double labelling experiments in fetal mice showing co-localization of the transgene with Sertoli and Leydig cell markers.β-hydroxysteroid dehydrogenase (3β-HSD) in Leydig cell areas. AMH expression was negative in Leydig cell conglomerates and tumours and variable in cord-like tumours. The SV40 T antigen and markers of cell proliferation (PCNA) were intensely positive in hyperplastic cells and tumours. Control mice of similar ages showed neither hyperplasia nor tumours, and SV40 T expression was always negative. In conclusion, transgenic mice develop large testicular tumours that are preceded by interstitial hyperplasia and microtumours. The histological and immunohistochemical phenotype of tumours (Leydig and Sertoli cell differentiation, positive 3β-HSD, and variable AMH) suggests a mixed differentiation of somatic cells of the specialized gonadal stroma. The finding that an oncogene directed by a promoter specifically active in fetal Sertoli cells has given rise to testicular tumours of mixed differentiation is compatible with a common origin of Leydig and Sertoli cells from the specific stroma of the gonadal ridge, as supported by double labelling experiments in fetal mice showing co-localization of the transgene with Sertoli and Leydig cell markers.β-HSD, and variable AMH) suggests a mixed differentiation of somatic cells of the specialized gonadal stroma. The finding that an oncogene directed by a promoter specifically active in fetal Sertoli cells has given rise to testicular tumours of mixed differentiation is compatible with a common origin of Leydig and Sertoli cells from the specific stroma of the gonadal ridge, as supported by double labelling experiments in fetal mice showing co-localization of the transgene with Sertoli and Leydig cell markers. Copyright  2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Keywords: somatic cell testicular tumours; Leydig cell hyperplasia; Sertoli and Leydig tumours; transgenic mice; tumour development; origin of Leydig cells; Sertoli cellssomatic cell testicular tumours; Leydig cell hyperplasia; Sertoli and Leydig tumours; transgenic mice; tumour development; origin of Leydig cells; Sertoli cells Received 20 January 2010; Revised 27 April 2010; Accepted 2 May 2010 No conflicts of interest were declared. Introduction Sertoli and Leydig cells are the main somatic cell components of the testis. Their embryonic origin in the coelomic epithelium and gonadal stroma is well accepted, but the existence of a common cell progenitor for both cell types has been repeatedly suggested, though never confirmed, to explain the existence of testicular tumours containing both cellular types. Sertoli and Leydig cell neoplasms are the most frequent sex cord-stromal tumour types in the testis. In recent years, we have characterized different varieties of human gonadal sex cord-stromal tumours [1–3]. First literature precedents on testicular somatic cell tumourigenesis were restricted to observational studies on the spontaneous incidence of Leydig tumours in different rat strains [4]. Other studies have involved oestrogens [5] and hCG [6] as inductors of Leydig cell hyperplasia and tumours. The recent development of mice transgenic models has singled out inhibins [7,8] and AMH [9] as suppressors of somatic cell tumour growth, and a model of aromatase overexpression [10] has resulted in the induction of Leydig cell tumours. In the present study, we have characterized somatic cell testicular tumours developed in transgenic mice bearing an AMH promoter–SV40 T construct as originally reported by Dutertre et al [11]. Special attention was paid to transgene expression in somatic cells at embryonic and early postnatal ages to better define the cellular origin, evolution, and phenotypic characteristics of the tumours.et al [11]. Special attention was paid to transgene expression in somatic cells at embryonic and early postnatal ages to better define the cellular origin, evolution, and phenotypic characteristics of the tumours. Copyright  2010 Pathological Society of Great Britain and Ireland. J Pathol 2010; 221: 443–451 Published by John Wiley & Sons, Ltd. www.pathsoc.org.uk www.thejournalofpathology.com 2010 Pathological Society of Great Britain and Ireland. J Pathol 2010; 221: 443–451 Published by John Wiley & Sons, Ltd. www.pathsoc.org.uk www.thejournalofpathology.com