The short-term reproductive toxicity of cyclophosphamide in the female rat

The ovary contains oocytes within immature (primordial) follicles that are fixed in number at birth. Activation of follicles within this fixed pool causes an irreversible decline in reproductive capacity, known as the ovarian reserve, until menopause. Premenopausal women undergoing commonly used genotoxic (DNA-damaging) chemotherapy experience an accelerated loss of the ovarian reserve, leading to subfertility and infertility. Therefore, there is considerable interest but little effective progress in preserving ovarian function during chemotherapy. Here we show that blocking the kinase mammalian/mechanistic target of rapamycin (mTOR) with clinically available small-molecule inhibitors preserves ovarian function and fertility during chemotherapy. Using a clinically relevant mouse model of chemotherapy-induced gonadotoxicity by cyclophosphamide, and inhibition of mTOR complex 1 (mTORC1) with the clinically approved drug everolimus (RAD001) or inhibition of mTORC1/2 with the experimental drug INK128, we show that mTOR inhibition preserves the ovarian reserve, primordial follicle counts, serum anti-Mullerian hormone levels (a rigorous measure of the ovarian reserve), and fertility. Chemotherapy-treated animals had significantly fewer offspring compared with all other treatment groups, whereas cotreatment with mTOR inhibitors preserved normal fertility. Inhibition of mTORC1 or mTORC1/2 within ovaries was achieved during chemotherapy cotreatment, concomitant with preservation of primordial follicle counts. Importantly, our findings indicate that as little as a two-to fourfold reduction in mTOR activity preserves ovarian function and normal birth numbers. As everolimus is approved for tamoxifen-resistant or relapsing estrogen receptor-positive breast cancer, these findings represent a potentially effective and readily accessible pharmacologic approach to fertility preservation during conventional chemotherapy. mTOR | fertility | chemotherapy | ovary | ovarian function

show abstract

“…S3). Studies have shown that rodents are capable of normal mating behavior as early as 14 d following CY exposure (27).…”

Section: Mtor Inhibition Prevents Chemotherapy-mediated Reduction Inmentioning

confidence: 99%

mTORC1/2 Inhibition Preserves Ovarian Function and Fertility During Genotoxic Chemotherapy

Goldman

Chenette

Arju

et al. 2017

Obstetrical &Amp; Gynecological Survey

View full text Add to dashboard Cite

show abstract

“…Conversely, chemicals that selectively damage large growing or antral follicles generally, only temporarily interrupt reproductive function because this follicles can be replaced by recruitment from the greater pool of primordial follicles. Thus, these chemicals produce a readily reversible form of infertility that is manifest relatively soon after exposure [20,21].…”

Section: Environmental Chemicals Affecting Ovarian Functionmentioning

confidence: 99%

Impact of endocrine disrupters on ovarian function and embryonic development

Gandolfi

Pocar²,

Brevini

et al. 2002

Domestic Animal Endocrinology

View full text Add to dashboard Cite

“…The oocyte is particularly sensitive to methotrexate and cyclophosphamide (95)(96)(97). Greatest risk to the oocyte occurs on the days just prior to ovulation (98).…”

Section: Controversy Within the Scientific Communitymentioning

confidence: 99%