Dexrazoxane Diminishes Doxorubicin-Induced Acute Ovarian Damage and Preserves Ovarian Function and Fecundity in Mice

Effect of AMH on primordial follicle populations in mouse ovaries and human pre-pubertal ovarian xenografts during doxorubicin treatment

Introduction

Survival rates of the childhood cancer patients are improving, however cancer treatments such as chemotherapy may lead to infertility due to loss of the primordial follicle (PMF) reserve. Doxorubicin (DXR) is a gonadotoxic chemotherapy agent commonly used in childhood cancers. Anti-Müllerian Hormone (AMH) has been reported to have a protective effect on the mouse ovarian reserve against DXR in vivo. However, whether AMH can prevent PMF loss in conjunction with DXR in human ovarian tissue in vivo has not been determined.

Methods

In order to investigate this, we first established an optimum dose of DXR that induced PMF loss in cultured mouse ovaries and investigated the efficacy of AMH on reducing DXR-induced PMF loss in mice in vitro. Second, we investigated the effects of DXR on pre-pubertal human ovarian tissue and the ability of AMH to prevent DXR-induced damage comparing using a mouse xenograft model with different transplantation sites.

Results

Mouse ovaries treated with DXR in vitro and in vivo had reduced PMF populations and damaged follicle health. We did not observe effect of DXR-induced PMF loss or damage to follicle/stromal health in human ovarian cortex, this might have been due to an insufficient dose or duration of DXR. Although AMH does not prevent DXR-induced PMF loss in pre-pubertal and adult mouse ovaries, in mouse ovaries treated with higher concentration of AMH in vitro, DXR did not cause a significant loss in PMFs. This is the first study to illustrate an effect of AMH on DXR-induced PMF loss on pre-pubertal mouse ovaries. However, more experiments with higher doses of AMH and larger sample size are needed to confirm this finding.

Discussion

We did not observe that AMH could prevent DXR-induced PMF loss in mouse ovaries in vivo. Further studies are warranted to investigate whether AMH has a protective effect against DXR in xenotransplanted human ovarian tissue. Thus, to obtain robust evidence about the potential of AMH in fertility preservation during chemotherapy treatment, alternative AMH administration strategies need to be explored alongside DXR administration to fully interrogate the effect of DXR and AMH on human xenografted tissues.

Ultrasonographic and histopathological investigation of the effect of N-acetylcysteine on doxorubicin-induced ovarian and uterine toxicity in rats

BACKGROUND

This study aimed to investigate the mitigating effect of N-acetylcysteine (NAC) on doxorubicin (DOX)-induced ovarian and uterine toxicity in rats using laboratory tests, ultrasonographic (US) imaging, and histopathology analysis.

METHODS

Forty-eight rats were divided into six groups (n = 8) as follows: Group A (control) (0.5 mL saline administered intraperitoneally [IP]), Group B (a single 10 mg/kg dose of DOX administered IP on day 1), Group C (a single 10 mg/kg dose of DOX administered IP 24 h before sacrifice), Group D (100 mg/kg of NAC administered IP for 21 days), Group E ( a single 10 mg/kg dose of DOX administered IP on day 1 and 100 mg/kg of NAC administered IP for 21 days), and Group F (100 mg/kg of NAC administered IP for 21 days and a single 10 mg/kg dose of DOX administered IP 24 h before sacrifice). The ovaries were examined using B-mode US on days 1, 14, and 21, and the histopathological examinations of the ovaries and the uterus were undertaken after sacrifice on day 22.

RESULTS

Histomorphological analyses showed that ovarian weight decreased after DOX administration in Group B but not in Group E. US revealed a transient increase in ovarian size in Group B and E, reverting to baseline levels over time, as well as a progressive increase in peritoneal fluid in Groups B and E. Group B exhibited a significant decrease in the thickness of the endometrium and myometrium and uterine cornual length, which was not observed in Group E. Histopathological examination showed that DOX caused a decline in follicular count, especially in primordial, secondary, and Graafian follicles, and resulted in follicular atresia, predominantly in Group B. Destructive degeneration/necrosis and vascular changes were most prominently seen in the corpus luteum of Groups C and B. In NAC-treated rats (Groups E and F), although germ cell damage was present, atretic follicles and vascular changes, such as hyperemia and congestion, were reduced. The anti-müllerian hormone (AMH) level was the highest in Group F.

CONCLUSIONS

NAC, an antioxidant, attenuated DOX-induced gonadotoxicity in rats.

Gynotoxic Effects of Chemotherapy and Potential Protective Mechanisms

Chemotherapy is one of the leading cancer treatments. Unfortunately, its use can contribute to several side effects, including gynotoxic effects in women. Ovarian reserve suppression and estrogen deficiency result in reduced quality of life for cancer patients and are frequently the cause of infertility and early menopause. Classic alkylating cytostatics are among the most toxic chemotherapeutics in this regard. They cause DNA damage in ovarian follicles and the cells they contain, and they can also induce oxidative stress or affect numerous signaling pathways. In vitro tests, animal models, and a few studies among women have investigated the effects of various agents on the protection of the ovarian reserve during classic chemotherapy. In this review article, we focused on the possible beneficial effects of selected hormones (anti-Müllerian hormone, ghrelin, luteinizing hormone, melatonin), agents affecting the activity of apoptotic pathways and modulating gene expression (C1P, S1P, microRNA), and several natural (quercetin, rapamycin, resveratrol) and synthetic compounds (bortezomib, dexrazoxane, goserelin, gonadoliberin analogs, imatinib, metformin, tamoxifen) in preventing gynotoxic effects induced by commonly used cytostatics. The presented line of research appears to provide a promising strategy for protecting and/or improving the ovarian reserve in the studied group of cancer patients. However, well-designed clinical trials are needed to unequivocally assess the effects of these agents on improving hormonal function and fertility in women treated with ovotoxic anticancer drugs.

Studies on the ameliorative potential of dietary supplemented different dose of selenium on doxorubicin-induced ovarian damage in rat

Doxorubicin (Dox) may induce loss of follicles, resulting in the depletion of ovarian reserve and consequent premature ovarian failure. Selenium (Se) is an oligoelement with fundamental biological features and is among the most common chemical inhibitor compounds. The present study describes the curative effects of dietary supplementation with different Se doses on Dox-induced ovarian damage in rats. In this study, 64 adult female Wistar rats were randomly separated into eight groups: Control group, Dox group (5 mg/kg intraperitoneal [i.p.]), low-dose Se (0.5 mg/kg i.p.), middle dose Se (1 mg/kg i.p.), high dose (Se 2 mg/kg i.p.), Dox + low-dose Se group (0.5 mg/kg i.p.), Dox + middle dose Se (1 mg/kg i.p.), and Dox + high-dose Se group (2 mg/kg i.p.). After the experiment, ovarian follicles were counted, and Antimüllerian hormone, interleukin 1 beta, tumor necrosis factor alpha, and caspase-3 expression were determined. Levels of malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase were biochemically measured in ovarian tissue. Dox caused ovarian injury, as evidenced by significant changes in ovarian markers, histological abnormalities, and the debilitation of antioxidant defense mechanisms. Furthermore, Dox therapy significantly changed the expression of inflammatory and apoptotic markers. Dox + 1 mg Se with various saturations was studied, and this study demonstrated both histopathological and follicular reserve and more protective features. 1 mg Se pretreatment improved Dox-induced ovarian toxicity through alleviating the antioxidant mechanism, decreasing inflammation and apoptosis, and restoring ovarian architecture. As a result, our findings indicate that 1 mg Se is a promising therapeutic agent for the prevention of ovarian damage associated with Dox.

CHEK2 signaling is the key regulator of oocyte survival after chemotherapy

Cancer treatments can damage the ovarian follicle reserve, leading to primary ovarian insufficiency and infertility among survivors. Checkpoint kinase 2 (CHEK2) deficiency prevents elimination of oocytes in primordial follicles in female mice exposed to radiation and preserves their ovarian function and fertility. Here, we demonstrate that CHEK2 also coordinates the elimination of oocytes after exposure to standard-of-care chemotherapy drugs. CHEK2 activates two downstream targets-TAp63 and p53-which direct oocyte elimination. CHEK2 knockout or pharmacological inhibition preserved ovarian follicle reserve after radiation and chemotherapy. However, the lack of specificity for CHEK2 among available inhibitors limits their potential for clinical development. These findings demonstrate that CHEK2 is a master regulator of the ovarian cellular response to damage caused by radiation and chemotherapy and warrant the development of selective inhibitors specific to CHEK2 as a potential avenue for ovario-protective treatments.

Chemotherapy-induced ovarian damage and protective strategies

More than 9.2 million women worldwide suffer from cancer, and about 5% of them are at reproductive age. Chemotherapy-induced impairment of fertility affects the quality of life of these women. Several chemotherapeutic agents have been proven to cause apoptosis and autophagy by inducing DNA damage and cellular stress. Injuries to the ovarian stroma and micro-vessel network are also considered as pivotal factors resulting in ovarian dysfunction induced by chemotherapeutic agents. Primordial follicle pool over-activation may also be the mechanism inducing damage to the ovarian reserve. Although many studies have explored the mechanisms involved in chemotherapy-induced reproductive toxicity, the exact molecular mechanisms have not been elucidated. It is essential to understand the mechanisms involved in ovarian damage, in order to develop potential protective treatments to preserve fertility. In this article, we reviewed the current knowledge on the mechanism of chemotherapy-induced ovarian damage and possible protective strategies that prevent the ovary from such damages.

Doxorubicin and other anthracyclines in cancers: Activity, chemoresistance and its overcoming

Anthracyclines have been important and effective treatments against a number of cancers since their discovery. However, their use in therapy has been complicated by severe side effects and toxicity that occur during or after treatment, including cardiotoxicity. The mode of action of anthracyclines is complex, with several mechanisms proposed. It is possible that their high toxicity is due to the large set of processes involved in anthracycline action. The development of resistance is a major barrier to successful treatment when using anthracyclines. This resistance is based on a series of mechanisms that have been studied and addressed in recent years. This work provides an overview of the anthracyclines used in cancer therapy. It discusses their mechanisms of activity, toxicity, and chemoresistance, as well as the approaches used to improve their activity, decrease their toxicity, and overcome resistance.

Mechanisms of doxorubicin-mediated reproductive toxicity - A review

The anticancer drug doxorubicin has been associated with several adverse side-effects including reproductive toxicity in both genders. The current review has complied the mechanisms of doxorubicin induced reproductive toxicity. The articles cited in the review were searched using Google Scholar, PubMed, Scopus, Science Direct. Doxorubicin treatment has been found to cause a decrease in testicular mass along with histopathological deformities, oligospermia and abnormalities in sperm morphology. Apart from severely affecting the normal physiological role of both Leydig cells and Sertoli cells, doxorubicin also causes chromosome abnormalities and affects DNA methylase enzyme. Testicular lipid metabolism has been found to be negatively affected by doxorubicin treatment resulting in altered profile of sphingolipids glycerophospholipids and neutral lipids. Dysregulation of 3β-hydroxysteroid dehydrogenase (3β-HSD) and 17β- hydroxysteroid dehydrogenase (17β-HSD) are strongly linked to testicular exposure to doxorubicin. Further, oxidative stress along with endoplasmic reticulum stress are also found to aggravate the male reproductive functioning in doxorubicin treated conditions. Several antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase (GPx) are downregulated by doxorubicin. It also disturbs the hormones of the hypothalamic-pituitary-gonadal (HPG)-axis including testosterone, luteinizing hormone, follicle stimulating hormone etc. In females, the drug disturbs folliculogenesis and oogenesis leading to failure of ovulation and uterine cycle. In rodent model the drug shortens pro-estrous and estrous phases. It was also found that doxorubicin causes mitochondrial dysfunction in oocytes with impaired calcium signaling along with ER stress. The goal of the present review is to comprehends various pathways due to which doxorubicin treatment promotes toxicity in male and female reproductive system.

Can Some Anticancer Treatments Preserve the Ovarian Reserve?

BACKGROUND

Preventing premature ovarian failure (POF) is a major challenge in oncology. With conventional regimens, cytotoxicity-associated POF involves primordial follicles (PF) pool depletion by apoptosis or overactivation mechanisms, notably mediated by the ABL/TAp63 and PI3K/Akt/mTOR pathways. New anticancer treatments have been designed to target pathways implicated in tumor growth. Although concerns regarding fertility arise with these targeted therapies, we hypothesized that targeted therapies may exert off-tumor effects on PF that might delay POF. We provide an overview of evidence concerning these off-tumor effects on PF. Limitations and future potential implications of these findings are discussed.

DESIGN

PubMed was searched by combining Boolean operators with the following keywords: fertility, ovarian, follicle, anti-tumoral, cancer, targeted, cytotoxic, and chemotherapy.

RESULTS

Cisplatin-related PF apoptosis via the ABL/TAp63 pathway was targeted with a tyrosine kinase inhibitor, imatinib, in mice, but effects were recently challenged by findings on human ovarian xenografts in mice. In cyclophosphamide-treated mice, PI3K/Akt/mTOR pathway inhibition with mTOR inhibitors and AS101 preserved the PF pool. Proteasome and GSK3 inhibitors were evaluated for direct and indirect follicle DNA damage prevention. Surprisingly, evidence for cytotoxic drug association with PF pool preservation was found. We also describe selected non-anticancer molecules that may minimize gonadotoxicity.

CONCLUSION

Not all anticancer treatments are associated with POF, particularly since the advent of targeted therapies. The feasibility of associating a protective drug targeting PF exhaustion mechanisms with cytotoxic treatments should be evaluated, as a way of decreasing the need for conventional fertility preservation techniques. Further evaluations are required for transfer into clinical practice.

IMPLICATIONS FOR PRACTICE

Anticancer therapies are associated with infertility in 10%-70% of patients, which is the result of primordial follicles pool depletion. Alone or associated with gonadotoxic treatments, some targeted therapies may exert favorable off-targets effects on the primordial follicle pool by slowing down their exhaustion. Current evidence of these effects relies on murine models or human in vitro models. Evaluation of these protective strategies in humans is challenging; however, if these results are confirmed with clinical and biological data, it not only could be a new approach to female fertility preservation but also would change standard fertility strategies.

DNA Damaged Induced Cell Death in Oocytes

The production of haploid gametes through meiosis is central to the principle of sexual reproduction. The genetic diversity is further enhanced by exchange of genetic material between homologous chromosomes by the crossover mechanism. This mechanism not only requires correct pairing of homologous chromosomes but also efficient repair of the induced DNA double-strand breaks. Oocytes have evolved a unique quality control system that eliminates cells if chromosomes do not correctly align or if DNA repair is not possible. Central to this monitoring system that is conserved from nematodes and fruit fly to humans is the p53 protein family, and in vertebrates in particular p63. In mammals, oocytes are stored for a long time in the prophase of meiosis I which, in humans, can last more than 50 years. During the entire time of this arrest phase, the DNA damage checkpoint remains active. The treatment of female cancer patients with DNA damaging irradiation or chemotherapeutics activates this checkpoint and results in elimination of the oocyte pool causing premature menopause and infertility. Here, we review the molecular mechanisms of this quality control system and discuss potential therapeutic intervention for the preservation of the oocyte pool during chemotherapy.

Irvingia gabonensis Seed Extract: An Effective Attenuator of Doxorubicin-Mediated Cardiotoxicity in Wistar Rats

Cardiotoxicity as an off-target effect of doxorubicin therapy is a major limiting factor for its clinical use as a choice cytotoxic agent. Seeds of Irvingia gabonensis have been reported to possess both nutritional and medicinal values which include antidiabetic, weight losing, antihyperlipidemic, and antioxidative effects. Protective effects of Irvingia gabonensis ethanol seed extract (IGESE) was investigated in doxorubicin (DOX)-mediated cardiotoxicity induced with single intraperitoneal injection of 15 mg/kg of DOX following the oral pretreatments of Wistar rats with 100-400 mg/kg/day of IGESE for 10 days, using serum cardiac enzyme markers (cardiac troponin I (cTI) and lactate dehydrogenase (LDH)), cardiac tissue oxidative stress markers (catalase (CAT), malonyldialdehyde (MDA), superoxide dismutase (SOD), glutathione-S-transferase (GST), glutathione peroxidase (GSH-Px), and reduced glutathione (GSH)), and cardiac histopathology endpoints. In addition, both qualitative and quantitative analyses to determine IGESE's secondary metabolites profile and its in vitro antioxidant activities were also conducted. Results revealed that serum cTnI and LDH were significantly elevated by the DOX treatment. Similarly, activities of tissue SOD, CAT, GST, and GSH levels were profoundly reduced, while GPx activity and MDA levels were profoundly increased by DOX treatment. These biochemical changes were associated with microthrombi formation in the DOX-treated cardiac tissues on histological examination. However, oral pretreatments with 100-400 mg/kg/day of IGESE dissolved in 5% DMSO in distilled water significantly attenuated increases in the serum cTnI and LDH, prevented significant alterations in the serum lipid profile and the tissue activities and levels of oxidative stress markers while improving cardiovascular disease risk indices and DOX-induced histopathological lesions. The in vitro antioxidant studies showed IGESE to have good antioxidant profile and contained 56 major secondary metabolites prominent among which are γ-sitosterol, Phytol, neophytadiene, stigmasterol, vitamin E, hexadecanoic acid and its ethyl ester, Phytyl palmitate, campesterol, lupeol, and squalene. Overall, both the in vitro and in vivo findings indicate that IGESE may be a promising prophylactic cardioprotective agent against DOX-induced cardiotoxicity, at least in part mediated via IGESE's antioxidant and free radical scavenging and antithrombotic mechanisms.

New insights into the activities and toxicities of the old anticancer drug doxorubicin

The anthracycline drug doxorubicin is among the most used—and useful—chemotherapeutics. While doxorubicin is highly effective in the treatment of various hematopoietic malignancies and solid tumours, its application is limited by severe adverse effects, including irreversible cardiotoxicity, therapy‐related malignancies and gonadotoxicity. This continues to motivate investigation into the mechanisms of anthracycline activities and toxicities, with the aim to overcome the latter without sacrificing the former. It has long been appreciated that doxorubicin causes DNA double‐strand breaks due to poisoning topoisomerase II. More recently, it became clear that doxorubicin also leads to chromatin damage achieved through eviction of histones from select sites in the genome. Evaluation of these activities in various anthracycline analogues has revealed that chromatin damage makes a major contribution to the efficacy of anthracycline drugs. Furthermore, the DNA‐damaging effect conspires with chromatin damage to cause a number of adverse effects. Structure–activity relationships within the anthracycline family offer opportunities for chemical separation of these activities towards development of effective analogues with limited adverse effects. In this review, we elaborate on our current understanding of the different activities of doxorubicin and their contributions to drug efficacy and side effects. We then offer our perspective on how the activities of this old anticancer drug can be amended in new ways to benefit cancer patients, by providing effective treatment with improved quality of life.

Mangiferin offers protection against deleterious effects of pharmaceuticals, heavy metals, and environmental chemicals

Mangiferin (MGF) is a polyphenolic C-glucosyl-xanthone extracted from the mango tree (Mangifera indica). MGF has shown diverse effects such as antioxidant, antiapoptotic, radical scavenging, and chelating properties. MGF also has been shown to modulate inflammatory pathways. In this review, we examined and evaluated the literature dealing with the protective effects of MGF against various chemical toxicities. Our literature review indicated that the MGF-induced protective effects against the toxic effects of pharmaceuticals, heavy metals and environmental chemicals were mainly mediated via suppression of lipid peroxidation, oxidative stress (along with enhancement of the antioxidant enzyme), inflammatory factors (TNF-α, IL-6, IL-10, and IL-12), and activation of PI3K/Akt and the MAPK survival signaling pathway.

Stereological and histopathological evaluation of doxorubicin-induced toxicity in female rats' ovary and uterus and palliative effects of quercetin and vitamin E

Doxorubicin (DOX) is a widely used chemotherapeutic agent with demonstrated reproductive toxicity. This study sought to determine the DOX-induced toxicity in the ovary and uterus and the preventive effects of quercetin (QCT) and vitamin E (Vit.E). Female rats were divided into six groups as follows: control, QCT (20 mg/kg), Vit.E (200 mg/kg), DOX (accumulative 15 mg/kg), DOX/QCT, and DOX/Vit.E. After 3 weeks, the toxicity of DOX in ovarian and uterine tissues and the potential palliative effects of QCT and Vit.E were evaluated by histopathological-stereological methods. The findings indicate a dramatic decline in the number of ovarian follicles (p < 0.001), ovarian and its associated structures volume, the volume of the uterus, its layers, and related structures (p < 0.05). Coadministration of QCT and Vit.E with DOX-treated rats demonstrated an alleviative effect on most of the studied parameters. Nevertheless, few adverse effects were recognized concerning these antioxidants administration (p < 0.05). In conclusion, the findings of this study support the protective role of these dietary supplements in the prevention of DOX-induced toxicity in uterine and ovarian tissues.

Doxorubicin induces cytotoxicity and miR-132 expression in granulosa cells

Doxorubicin (DOX) is one of the most commonly used drugs for the treatment of childhood cancers, including leukemia and lymphomas. Despite the high survival rate, female leukemia survivors are at higher risk of ovarian failure and infertility later in life. Treatment with chemotherapeutic drugs like DOX is associated with damage in ovarian follicles, but the affectation grade of granulosa cells remains unclear. To assess and avoid the possible side-effects of DOX, early biomarkers of ovarian injury and chemotherapy-induced ovarian toxicity should be identified. MicroRNAs (miRNAs) have emerged in recent years as a promising new class of biomarkers for drug-induced tissue toxicity. In this study, the effects of DOX on cell viability, steroidogenesis, and miRNA expression were studied in primary granulosa cells (GCs) and in two cellular models (COV434 and KGN cells). We report that compared to other chemotherapeutic drugs, DOX treatment is more detrimental to granulosa cells as observed by decrease of cell viability. Treatment with DOX changes the expression of the aromatase gene (CYP19A1) and the secretion of 17β-estradiol (E2) in a cell-specific manner. miR-132-3p is dose-dependently increased by DOX in all cellular models. In absence of DOX, miR-132-3p overexpression in COV434 cells has no effect on E2 secretion or CYP19A1 expression. Altogether, these findings contribute to understanding the hormonal disbalance caused by DOX in human ovarian cells and suggest miR-132 as a putative sensor to predict DOX-induced ovarian toxicity.

Ovarian damage from chemotherapy and current approaches to its protection

BACKGROUND

Anti-cancer therapy is often a cause of premature ovarian insufficiency and infertility since the ovarian follicle reserve is extremely sensitive to the effects of chemotherapy and radiotherapy. While oocyte, embryo and ovarian cortex cryopreservation can help some women with cancer-induced infertility achieve pregnancy, the development of effective methods to protect ovarian function during chemotherapy would be a significant advantage.

OBJECTIVE AND RATIONALE

This paper critically discusses the different damaging effects of the most common chemotherapeutic compounds on the ovary, in particular, the ovarian follicles and the molecular pathways that lead to that damage. The mechanisms through which fertility-protective agents might prevent chemotherapy drug-induced follicle loss are then reviewed.

SEARCH METHODS

Articles published in English were searched on PubMed up to March 2019 using the following terms: ovary, fertility preservation, chemotherapy, follicle death, adjuvant therapy, cyclophosphamide, cisplatin, doxorubicin. Inclusion and exclusion criteria were applied to the analysis of the protective agents.

OUTCOMES

Recent studies reveal how chemotherapeutic drugs can affect the different cellular components of the ovary, causing rapid depletion of the ovarian follicular reserve. The three most commonly used drugs, cyclophosphamide, cisplatin and doxorubicin, cause premature ovarian insufficiency by inducing death and/or accelerated activation of primordial follicles and increased atresia of growing follicles. They also cause an increase in damage to blood vessels and the stromal compartment and increment inflammation. In the past 20 years, many compounds have been investigated as potential protective agents to counteract these adverse effects. The interactions of recently described fertility-protective agents with these damage pathways are discussed.

WIDER IMPLICATIONS

Understanding the mechanisms underlying the action of chemotherapy compounds on the various components of the ovary is essential for the development of efficient and targeted pharmacological therapies that could protect and prolong female fertility. While there are increasing preclinical investigations of potential fertility preserving adjuvants, there remains a lack of approaches that are being developed and tested clinically.

Melatonin protects against Epirubicin-induced ovarian damage

One major side effect of chemotherapy that young women with cancer suffer from is ovarian damage. Therefore, it is necessary to study the pathogenesis of chemotherapeutic drugs in order to develop pharmaceutical agents to preserve fertility. Epirubicin is one of the commonly used chemotherapy drugs for breast cancer patients. This research explored the side effects of epirubicin in mice. We found that epirubicin significantly reduced the body weight, the weight of the ovaries and uteri, and the pups' number, while melatonin, which is extremely resistant to oxidation, significantly reduced these damages. Moreover, co-treatment with melatonin prevented epirubicin-induced decrease in E<inf>2</inf> and progesterone, and the loss of follicles. Mechanism study showed that melatonin significantly reduced the levels of proapoptotic genes p53, Caspase3, and Caspase9 while it upregulated antiapoptotic factors Bcl-2 and Bcl2l1, and antioxidant genes superoxide dismutase 1 and catalase compared with the epirubicin group. In addition, melatonin markedly reduced reactive oxygen species (ROS) and the transcription of Caspase12 and Chop, which is vital in endoplasmic reticulum stress (ERS)-mediated apoptosis. These results indicate melatonin protects against epirubicin-induced ovarian damage by reducing ROS-induced ERS. Therefore, melatonin has a therapeutic potential for the protection of ovarian function and preservation of fertility during chemotherapy.

Consequences of chemotherapeutic agents on primordial follicles and future clinical applications

The ovarian reserve is necessary for female fertility and endocrine health. Commonly used cancer therapies diminish the ovarian reserve, thus, resulting in primary ovarian insufficiency, which clinically presents as infertility and endocrine dysfunction. Prepubertal children who have undergone cancer therapies often experience delayed puberty or cannot initiate puberty and require endocrine support to maintain a normal life. Thus, developing an effective intervention to prevent loss of the ovarian reserve is an unmet need for these cancer patients. The selection of adjuvant therapies to protect the ovarian reserve against cancer therapies underlies the mechanism of loss of primordial follicles (PFs). Several theories have been proposed to explain the loss of PFs. The "burn out" theory postulates that chemotherapeutic agents activate dormant PFs through an activation pathway. Another theory posits that chemotherapeutic agents destroy PFs through an "apoptotic pathway" due to high sensitivity to DNA damage. However, the mechanisms causing loss of the ovarian reserve remains largely speculative. Here, we review current literature in this area and consider the mechanisms of how gonadotoxic therapies deplete PFs in the ovarian reserve.

Ovarian Follicle Depletion Induced by Chemotherapy and the Investigational Stages of Potential Fertility-Protective Treatments-A Review

Ovarian follicle pool depletion, infertility, and premature menopause are all known sequelae of cancer treatment that negatively impact the quality of life of young cancer survivors. The mechanisms involved in this undesired iatrogenic ovarian damage have been intensively studied, but many of them remain unclear. Several chemotherapeutic drugs have been shown to induce direct and indirect DNA-damage and/or cellular stress, which are often followed by apoptosis and/or autophagy. Damage to the ovarian micro-vessel network induced by chemotherapeutic agents also seems to contribute to ovarian dysfunction. Another proposed mechanism behind ovarian follicle pool depletion is the overactivation of primordial follicles from the quiescent pool; however, current experimental data are inconsistent regarding these effects. There is great interest in characterizing the mechanisms involved in ovarian damage because this might lead to the identification of potentially protective substances as possible future therapeutics. Research in this field is still at an experimental stage, and further investigations are needed to develop effective and individualized treatments for clinical application. This review provides an overview of the current knowledge and the proposed hypothesis behind chemotherapy-induced ovarian damage, as well as current knowledge on possible co-treatments that might protect the ovary and the follicles from such damages.

Fertility Preservation in Women With Malignancy: Future Endeavors

The area of fertility preservation is constantly developing. To date, the only noninvestigational and unequivocally accepted methods for fertility preservation are cryopreservation of embryos and unfertilized oocytes. This article is one of several in a monogram on fertility preservation. The debate, pros and cons, and equivocal data on the use of GnRH analogues for fertility preservation are elaborated by 3 other manuscripts, in this monogram. A repeat of the arguments, pros and cons of this debatable issue, would be a repetition and redundancy of what is already included in this monogram. The subject of ovarian cryopreservation for fertility preservation is also elaborated by several other authors in this monogram. It is possible that, in the not too far future, the technologies of in vitro maturation of primordial follicles to metaphase 2 oocytes, and the “artificial ovary,” will turn clinically available. These technologies may bypass the risk of resuming malignancy by autotransplantation of cryopreserved-thawed ovarian tissue in leukemia and diseases where malignant cells may persist in the cryopreserved ovarian tissue. We summarize here the suggested options for future endeavors in fertility preservation.

Epigallocatechin-3-gallate inhibits doxorubicin-induced inflammation on human ovarian tissue

Chemotherapy protocol can destroy the reproductive potential of young cancer patients. Doxorubicin (DOX) is a potent anthracycline commonly used in the treatment of numerous malignancies. The purpose of the study was to evaluate the ovarian toxicity of DOX via inflammation and the possible protective effect of the green tea polyphenol epigallocatechin-3-gallate (EGCG). Ovarian tissue of three patients was cultured with 1 µg/ml DOX and/or 10 µg/ml EGCG for 24 and 48 h. Levels of inflammatory factors were determined by quantitative Real-Time PCR, western blot, zimography, and multiplex bead-based immunoassay. Morphological evaluation, damaged follicle count and TUNEL assay were also performed. DOX influenced inflammatory responses by inducing a significant increase in the expression of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and cyclooxigenase-2 (COX-2), of inflammatory interleukins (IL), such as interleukin-6 (IL-6) and interleukin-8 (IL-8), and the inflammatory proteins mediators metalloproteinase-2 and metalloproteinase-9 (MMP2 and MMP9). IL-8 secretion in the culture supernatants and MMP9 activity also significantly raised after DOX treatment. Moreover, a histological evaluation of the ovarian tissue showed morphological damage to follicles and stroma after DOX exposure. EGCG significantly reduced DOX-induced inflammatory responses and improved the preservation of follicles. DOX-induced inflammation could be responsible for the ovarian function impairment of chemotherapy. EGCG could have a protective role in reducing DOX-mediated inflammatory responses in human ovarian tissue.

Multidrug Resistance Protein 1 Deficiency Promotes Doxorubicin-Induced Ovarian Toxicity in Female Mice

Multidrug resistance protein 1 (MDR1), a phase III drug transporter that exports substrates out of cells, has been discovered in both cancerous and normal tissues. The over expression of MDR1 in cancer cells contributes to multiple drug resistance, whereas the MDR1 in normal tissues protects them from chemical-induced toxicity. Currently, the role of MDR1 in the ovary has not been entirely understood. Our objective is to determine the function of MDR1 in protecting against chemotherapy-induced ovarian toxicity. Using both the in vivo transgenic mouse model and in vitro follicle culture model, we investigated the expression of MDR1 in the ovary, the effect of MDR1 deficiency on doxorubicin (DOX)-induced ovarian toxicity, and the ovarian steroid hormonal regulation of MDR1. Results showed that the MDR1 was expressed in the ovarian epithelial cells, stroma cells, theca cell layers, endothelial cells, and luteal cells. The lack of MDR1 did not affect female ovarian function and fertility; however, its deficiency significantly exacerbated the DOX-induced ovarian toxicity in both in vivo and in vitro models. The MDR1 showed significantly higher expression levels in the ovaries at estrus and metestrus stages than those at proestrus and diestrus stages. However, this dynamic expression pattern was not regulated by the ovarian steroid hormones of estrogen (E2) and progesterone (P4) but correlated to the number and status of corpus luteum. In conclusion, our study demonstrates that the lack of MDR1 promotes DOX-induced ovarian toxicity, suggesting the critical role of MDR1 in protecting female ovarian functions during chemotherapy.

The cardioprotective effect of dexrazoxane (Cardioxane) is consistent with sequestration of poly(ADP-ribose) by self-assembly and not depletion of topoisomerase 2B

Following systematic scrutiny of the evidence in support of the hypothesis that the cardioprotective mechanism of action of dexrazoxane is mediated by a 'depletion' or 'downregulation' of Top2β protein levels in heart tissue, the author concludes that this hypothesis is untenable. In seeking to understand how dexrazoxane protects the heart, the outcomes of a customised association rule learning algorithm incorporating the use of antecedent surrogate variables (CEME, 2017 McCormack Pharma) reveal a previously unknown relationship between dexrazoxane and poly(ADP-ribose) (PAR) polymer. The author shows how this previously unknown relationship explains both acute and long-term cardioprotection in patients receiving anthracyclines. In addition, as a direct inhibitor of PAR dexrazoxane has access to the epigenome and this offers a new insight into protection by dexrazoxane against doxorubicin-induced late-onset damage [McCormack K, manuscript in preparation]. Notably, through this review article, the author illustrates the practical application of probing natural language text using an association rule learning algorithm for the discovery of new and interesting associations that, otherwise, would remain lost. Historically, the use of CEME enabled the first report of the capacity of a small molecule to catalyse the hybrid self-assembly of a nucleic acid biopolymer via canonical and non-canonical, non-covalent interactions analogous to Watson Crick and Hoogsteen base pairing, respectively.

Doxorubicin Has Dose-Dependent Toxicity on Mouse Ovarian Follicle Development, Hormone Secretion, and Oocyte Maturation

Doxorubicin (DOX), one of the most commonly used anticancer medications, has been reported to affect fertility by damaging ovarian follicles; however, the dose-dependent toxicity of DOX on the dynamic follicle development and oocyte maturation has not been well-defined. Our objective is to determine the effects of human-relevant exposure levels of DOX on follicular functions across developmental time. In vitro cultured multilayered secondary mouse follicles were treated with DOX at 0, 2, 20, 100, and 200 nM for 24 h, and follicle development, hormone secretion, and oocyte maturation were analyzed. DOX caused dose-dependent toxicity on follicle growth, survival, and secretion of 17β-estradiol (E2). At 200 nM, DOX induced DNA damage and apoptosis in follicle somatic cells first and then in oocytes, which was correlated with the uptake of DOX first to the somatic cells followed by germ cells. Follicles treated with DOX at 0, 2, and 20 nM showed similar oocyte metaphase II (MII) percentages after in vitro oocyte maturation; however, 20 nM DOX significantly increased the number of MII oocytes with abnormal spindle morphology and chromosome misalignment. In an effort to harmonize the in vitro study to in vivo treatment, dose-dependent toxicity on oocyte meiotic maturation was found in 16-day-old CD-1 mice treated with DOX at 0, 0.4, 2, and 10 mg/kg, consistent with the in vitro oocyte maturation outcomes. Our study demonstrates that DOX has dose-dependent toxicity on ovarian follicle development, hormone secretion, and oocyte maturation, which are three key factors to support the female reproductive and endocrine functions.

Mechanisms of chemotherapy-induced ovarian damage in breast cancer patients

Fertility preservation in breast cancer patients is an increasingly relevant topic. In the present paper we review available data on the mechanism of ovarian damage caused by anticancer agents currently used for the treatment of breast cancer. We also describe current methods to preserve fertility including oocytes or ovarian tissue freezing and administration of LH-RHa during chemotherapy. The aim of the paper is to provide clinical oncologists with an adequate knowledge of the subject to enable them to give a correct counselling to young women that must receive chemotherapy and want to increase their possibilities of maintaining fertility.

The comparison of animal models for premature ovarian failure established by several different source of inducers

The objective of this study was to compare premature ovarian failure animal models established by several different source of inducers. Female ICR mice, KM mice, and SD rats were treated by cyclophosphamide at 120 mg/kg, busulfan at 12 mg/kg, cisplatin at 3 or 4 mg/kg, 4-vinylcyclohexene diepoxide at 160 mg/kg, 35% galactose food pellet, and tripterygium glycosides at 50 mg/kg, respectively. Parameters were analyzed by body weight, serum concentration level of related hormones, ovarian and uterine pathological examination. The results indicated the body weight of mice increased very slowly following single dose of cyclophosphamide (p < 0.05) with damaged ovary; repeated doses of cisplatin could induce body weight significantly decreased (p < 0.01) with a rising trend of serum LH concentration, declining tendency of serum E2 concentration and injured ovary and uterus; 4-vinylcyclohexene diepoxide also hindered the mice growing (p < 0.05) with damaged ovary and uterus; the body weight of mice feed by 35% galactose food pellet increased slowly (p < 0.05) with dramatically higher serum concentration level of galactose, albumin, and total protein (p < 0.001) and injured ovary. Busulfan and tripterygium glycosides did not present obvious evidences. In conclusion, the inducers presented their respective features in such animal models and should be appropriately applied in preventive methods.

An ovarian bioreactor for in vitro culture of the whole bovine ovary: a preliminary report

Background

Improved cancer therapeutics and enhanced cancer survivorship have emphasized the severe long-term side effects of chemotherapy. Specifically, studies have linked many chemotherapy agents with primary ovarian insufficiency, although an exact insult model has not yet been determined. To investigate and ultimately solve this problem, a novel device for extended study of mammalian ovaries in vitro was developed.

Methods

A bioreactor was fabricated for bovine ovarian culture that provides intravascular delivery of media to the ovary through isolation and cannulation of a main ovarian artery branch. Whole ovaries were cultured in vitro using three methods: (1) continuously supplied fresh culture media, (2) recirculated culture media, or (3) continuously supplied fresh culture media supplemented with 500 nM doxorubicin for 24 or 48 h. TUNEL assay was used to assess apoptotic cell percentages in the three groups as compared to uncultured baseline ovaries.

Results

The ovary culture method was shown to maintain cell viability by effectively delivering nutrient-enriched pH-balanced media at a constant flow rate. Lower apoptosis observed in ovaries cultured in continuously supplied fresh culture media illustrates that this culture device and method are the first to sustain whole bovine ovary viability for 48 h. Meanwhile, the increase in the percentage of cell apoptosis with doxorubicin treatment indicates that the device can provide an alternative model for testing chemotherapy and chemoprotection treatments to prevent primary ovarian insufficiency in cancer patients.

Conclusions

An ovarian bioreactor with consistent culture media flow through an ovarian vasculature-assisted approach maintains short-term whole bovine ovary viability.

Electronic supplementary material

The online version of this article (doi:10.1186/s13048-016-0249-4) contains supplementary material, which is available to authorized users.

Impaired mitochondrial function is abrogated by dexrazoxane in doxorubicin-treated childhood acute lymphoblastic leukemia survivors

BACKGROUND

Impaired cardiac function in doxorubicin-treated childhood cancer survivors is partly mediated by the disruption of mitochondrial energy production. Doxorubicin intercalates into mitochondrial DNA (mtDNA) and disrupts genes encoding for polypeptides that make adenosine triphosphate.

METHODS

This cross-sectional study examined mtDNA copy numbers per cell and oxidative phosphorylation (OXPHOS) in peripheral blood mononuclear cells (PBMCs) in 64 childhood survivors of high-risk acute lymphoblastic leukemia (ALL) who had been treated on Dana-Farber Cancer Institute childhood ALL protocols and had received doxorubicin alone (42%) or doxorubicin with the cardioprotectant dexrazoxane (58%). The number of mtDNA copies per cell and the OXPHOS enzyme activity of nicotinamide adenine dinucleotide dehydrogenase (complex I [CI]) and cytochrome c oxidase (complex IV [CIV]) were measured with quantitative real-time polymerase chain reaction immunoassays and thin-layer chromatography, respectively.

RESULTS

At a median follow-up of 7.8 years after treatment, the median number of mtDNA copies per cell for patients treated with doxorubicin alone (1106.3) was significantly higher than the median number for those who had also received dexrazoxane (310.5; P = .001). No significant differences were detected between the groups for CI or CIV activity.

CONCLUSIONS

Doxorubicin-treated survivors had an increased number of PBMC mtDNA copies per cell, and concomitant use of dexrazoxane was associated with a lower number of mtDNA copies per cell. Because of a possible compensatory increase in mtDNA copies per cell to maintain mitochondrial function in the setting of mitochondrial dysfunction, overall OXPHOS activity was not different between the groups. The long-term sustainability of this compensatory response in these survivors at risk for cardiac dysfunction over their lifespan is concerning.