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Updated: Sep 20, 2025
Germ Cell Transplantation and Testis Tissue Xenografting in Mice
Published on: February 6, 2012
Testicular cancer in mice: interplay between stem cells and endocrine insults
Ankita Kaushik1, Deepa Bhartiya2
1Stem Cell Biology Department, ICMR-National Institute for Research in Reproductive and Child Health, Jehangir Merwanji Street, Parel, Mumbai, 400 012, India.
Background:
Incidence of type II germ cell tumors (T2GCT) has increased in young men possibly due to fetal/perinatal exposure to estrogenic compounds. Three-fold increased incidence of T2GCT was reported in men exposed in utero to diethylstilbestrol (DES). T2GCT is a development-related disease arising due to blocked differentiation of gonocytes into spermatogonia in fetal testes which survive as germ cell neoplasia in situ (GCNIS) and initiate T2GCT. In our earlier study, T2GCT-like features were observed in 9 out of 10 adult, 100-day-old mice testes upon neonatal exposure to DES (2 μg/pup/day on days 1-5). Neonatal DES exposure affected testicular very small embryonic-like stem cells (VSELs) and spermatogonial stem cells and resulted in infertility, reduced sperm counts and tumor-like changes leading to our postulate that testicular dysgenesis syndrome possibly has a stem cell basis. The present study was undertaken to further characterize testicular tumor in mice testes.
Methods:
DES-exposed mice pups (n = 70) were studied on D100 and after 12 months to understand how T2GCT progresses. Besides histological studies, a carefully selected panel of markers were studied by immuno-fluorescence and qRT-PCR.
Results:
DES resulted in either atrophied or highly vascularized, big-sized testes and extra-testicular growth was also observed. GCNIS-like cells with big, vacuolated cytoplasm and increased expression of OCT-4, SSEA-1, SCA-1 and CD166 (cancer stem cells marker) along with reduced c-KIT, MVH and PTEN were evident. Global hypomethylation was found associated with altered expression of Dnmts, Igf2-H19 and Dlk-Meg3 imprinted genes along with reduced expression of Ezh2, cell cycle regulator p57KIP2 and Meg3; however, Pten remained unaltered. Increased expression of PCNA and Ki67 was observed in concert with complete lack of SOX-9 suggesting Sertoli cells independent proliferation.
Conclusions:
Mouse model for T2GCT is described which will have immense potential to understand cancer initiation, cancer stem cells and also to develop effective therapies in future. T2GCT initiates from tissue-resident, pluripotent VSELs due to their altered epigenome. Neonatal exposure to DES blocks differentiation (spermatogenesis) and VSELs get transformed into CD166 positive cancer stem cells that undergo excessive self-renewal and initiate cancer in adult life challenging existing concept of fetal origin of T2GCT.
Insights
Neonatal exposure to diethylstilbestrol (DES) in mice can lead to type II germ cell tumors (T2GCT) by altering testicular stem cells. This mouse model helps understand T2GCT initiation and develop future therapies.
Area of Science:
- Reproductive biology
- Developmental toxicology
- Cancer research
Background:
- Type II germ cell tumors (T2GCT) incidence is rising in young men, potentially linked to fetal exposure to estrogenic compounds like diethylstilbestrol (DES).
- T2GCT arises from blocked differentiation of fetal gonocytes, forming germ cell neoplasia in situ (GCNIS).
- Previous studies showed T2GCT-like features in mice neonatally exposed to DES, suggesting a stem cell basis for testicular dysgenesis syndrome.
Purpose of the Study:
- To further characterize testicular tumors in mice following neonatal DES exposure.
- To investigate the progression and molecular mechanisms of T2GCT development in a mouse model.
- To explore the role of stem cells and epigenetic alterations in T2GCT initiation.
Main Methods:
- Neonatal mice were exposed to DES and studied at 100 days and 12 months post-exposure.
- Histological analysis of testes was performed.
- Key markers were studied using immunofluorescence and quantitative reverse transcription PCR (qRT-PCR).
Main Results:
- DES exposure resulted in testicular abnormalities, including atrophied or enlarged testes and extra-testicular growth.
- GCNIS-like cells showed increased expression of stem cell markers (OCT-4, SSEA-1, SCA-1, CD166) and reduced expression of c-KIT, MVH, and PTEN.
- Global hypomethylation and altered expression of imprinted genes (Igf2-H19, Dlk-Meg3) were observed, alongside changes in Ezh2, p57KIP2, and Pten.
Conclusions:
- A mouse model for T2GCT was established, offering potential for studying cancer initiation and stem cells.
- T2GCT originates from tissue-resident, pluripotent very small embryonic-like stem cells (VSELs) with altered epigenomes.
- Neonatal DES exposure blocks spermatogenesis, transforming VSELs into cancer stem cells, challenging the fetal origin theory of T2GCT.
