Impact of the Chemotherapy Cocktail Used to Treat Testicular Cancer on the Gene Expression Profile of Germ Cells from Male Brown-Norway Rats1

Abstract

Advances in treatment for testicular cancer that include the coadministration of bleomycin, etoposide, and cisplatin (BEP) have brought the cure rate to higher than 90%%. The goal of this study was to elucidate the impact of BEP treatment on gene expression in male germ cells. Brown-Norway rats were treated for 9 wk with vehicle (0x) or BEP at doses equivalent to 0.3x and 0.6x the human dose. At the end of treatment, spermatogenesis was affected, showing altered histology and a decreased sperm count; spermatozoa had a higher number of DNA breaks. After 9 wk of treatment, round spermatids were isolated, and RNA was extracted and probed on Rat230-2.0 Affymetrix arrays. Of the 31 099 probe sets present on the array, 59%% were expressed in control round spermatids. BEP treatment significantly altered the expression of 221 probe sets, with at least a 1.5-fold change compared with controls; 80% were upregulated. We observed a dose-dependent increase in the expression of oxidative stress response genes and no change in the expression of genes involved in DNA repair. BEP upregulated genes were implicated in pathways related to Jun and Junb protooncogenes. Increased mRNA levels of Jun and Junb were confirmed by quantitative RT-PCR; furthermore, JUN protein was increased in elongating spermatids. Thus, BEP exposure triggers an oxidative stress response in round spermatids and induces many pathways that may lead to the survival of damaged cells and production of abnormal sperm.

Role of melatonin in mitigating chemotherapy-induced testicular dysfunction in Wistar rats

“…Impairment of spermatogenesis is one of the earlier signs of the adverse effects of chemotherapy as sperm counts of patients decrease following cisplatin treatment (Gandini et al, 2006). Earlier studies show that treatment with BEP induces adverse changes on male reproduction which includes decrease in reproductive tissue indices (Delbes et al, 2009), loss of germ cells and seminiferous tubular atrophy (Atessahin et al, 2006;Boekelheide, 2005;Sawhney et al, 2005), reduction in androgen biosynthesis (Maines et al, 1990). Cisplatin-based chemotherapy also resulted in deterioration of Sertoli cell function and decreased production of androgen binding protein (Monsees et al, 2000).…”

Cisplatin-induced alterations in the functional spermatogonial stem cell pool and niche in C57/BL/6J mice following a clinically relevant multi-cycle exposure

“…Most published studies seeking to recapitulate a clinical cisplatin treatment paradigm have employed an acute exposure model (Bieber et al , 2006; Delbes et al , 2009; Favareto et al , 2011; Ilbey et al , 2009a; Ilbey et al , 2009b; Marcon, Hales and Robaire, 2008; Seethalakshmi et al , 1992). The treatment model in this study differs from the reports that do use a multi cycle regimen in a number of critical variables: the species and age of the model organism, the daily dose, the cumulative dose, the length and number of exposure cycles and recovery periods, the vehicle, the administration route, and other compounds given in concert with cisplatin (Bieber, Marcon, Hales and Robaire, 2006; Delbes, Chan, Pakarinen, Trasler, Hales and Robaire, 2009; Favareto, Fernandez, da Silva, Anselmo-Franci and Kempinas, 2011; Ilbey, Ozbek, Cekmen, Simsek, Otunctemur and Somay, 2009a; Ilbey, Ozbek, Simsek, Cekmen, Otunctemur and Somay, 2009b; Marcon, Hales and Robaire, 2008; Seethalakshmi, Flores, Kinkead, Carboni, Malhotra and Menon, 1992). Chiefly, the multi-cycle cisplatin paradigm utilized in this study closely simulates the manner in which cisplatin is administered clinically, conforming to prescribed daily and cumulative dose, length and timing of dosing and recovery periods, and number of cycles (Sawhney, Giammona, Meistrich and Richburg, 2005) (Figure 1).…”

Exposure to Bleomycin, Etoposide, and Cis-Platinum Alters Rat Sperm Chromatin Integrity and Sperm Head Protein Profile1

“…Several studies have also reported alterations in rat sperm protein profiles after exposure to various chemicals [28,29]. Furthermore, the transcriptome of round spermatids following BEP treatment is modified extensively, with a specific increase in genes involved in stress response pathways [15].…”

“…Animals were provided with food and water ad libitum, and all experiments were conducted in accordance with the principles and procedures outlined in A Guide to the Care and Use of Experimental Animals prepared by the Canadian Council on Animal Care (McGill Animal Research Centre protocol 5619). Rats were treated (n ¼ 12 per group) as previously described [7,15] with a few modifications. Briefly, drug-treated animals received three cycles of 3 wk (9 wk) of the BEP regimen at a therapeutically relevant dose of 0.63, with a 13 dose being equivalent to the human treatment regimen, as adjusted for weight and surface area.…”