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A molecular evaluation of germ cell death induced by etoposide in pubertal rat testes
Rina J Ortiz1, Carlos Lizama, Verónica A Codelia
1Departamento de Ciencias Fisiológicas, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.
Abstract:
Etoposide is widely used in the treatment of patients with testicular cancer. The mechanism underlying apoptosis induction in cancer cells has been studied in different cell types, but it is not known whether the same factors participate in viable germ cells undergoing programmed cell death. Since testicular cancer primarily affects young males, we used pubertal rats (21 days old) as a model to determine different apoptotic parameters after etoposide treatment in healthy testes. We found that one intratesticular injection of etoposide (1.2 microg/testis) induced a significant increase in spermatocytes undergoing apoptosis, along with activation of caspase-9, -8 and -3 after 24 h of treatment. Spermatocyte apoptosis was inhibited when a general caspase inhibitor was added along with etoposide. Etoposide induces a significant stabilization/activation of p53, resulting in an increase level of this protein. The mRNA of Bcl-2 antagonist of cell death (BAD), a pro-apoptotic gene and a transcriptional target of p53, was significantly increased after etoposide treatment. Thus, our results suggest a single injection of etoposide induces apoptosis in healthy pachytene spermatocytes mediated by p53 and caspase activation. These findings will assist the search for new therapies to prevent the deleterious effect of cancer drugs upon normal cells.
Insights
Etoposide triggers apoptosis in healthy testicular cells via p53 and caspase activation. This study clarifies the mechanism of etoposide-induced germ cell death, aiding in developing protective therapies.
Area of Science:
- Reproductive biology
- Cancer biology
- Cellular toxicology
Background:
- Etoposide is a key chemotherapy for testicular cancer.
- The mechanism of etoposide-induced apoptosis in normal germ cells is not well understood.
- Testicular cancer predominantly affects young males, highlighting the need to protect healthy testicular cells.
Purpose of the Study:
- To investigate the apoptotic pathways activated by etoposide in healthy testicular germ cells.
- To determine the role of p53 and caspases in etoposide-induced spermatocyte apoptosis.
- To establish a model for studying chemotherapy side effects on normal testes.
Main Methods:
- Pubertal rats (21 days old) were treated with etoposide (1.2 microg/testis).
- Apoptotic parameters, including caspase activation (caspase-9, -8, -3), p53 levels, and BAD mRNA expression, were analyzed 24 hours post-treatment.
- Caspase activity was assessed using a general caspase inhibitor.
Main Results:
- Etoposide significantly increased apoptosis in pachytene spermatocytes.
- Activation of caspase-9, -8, and -3 was observed 24 hours after etoposide administration.
- Etoposide treatment led to p53 stabilization/activation and increased levels of the pro-apoptotic gene BAD mRNA.
- Caspase inhibition significantly reduced etoposide-induced spermatocyte apoptosis.
Conclusions:
- A single etoposide injection induces apoptosis in healthy pachytene spermatocytes.
- The process is mediated by the p53 tumor suppressor and caspase activation.
- These findings provide insights into protecting normal testicular cells from chemotherapy-induced damage.
