Unraveling the mechanisms of chemotherapy-induced damage to human primordial follicle reserve: road to developing therapeutics for fertility preservation and reversing ovarian aging

Does gonadotoxic chemotherapy deplete the ovarian reserve through activation of primordial follicles?

Despite significant advances in fertility preservation, no proven pharmacological options exist to protect ovarian primordial follicle reserve from chemotherapy-induced damage. Developing targeted gonadoprotective treatments will require an improved understanding of the molecular mechanisms underlying chemotherapy-induced primordial follicle depletion. While there is robust evidence that gonadotoxic chemotherapy induces primordial follicle death by causing DNA double-strand breaks which trigger apoptotic death, follicle activation leading to 'burn-out' of the ovarian reserve has been suggested as an alternative mechanism. Here, we critically evaluated whether primordial follicle activation is a significant mechanism of chemotherapy-induced ovarian reserve depletion in humans. We assessed the causal relationship between chemotherapy exposure and primordial follicle activation by applying the Bradford Hill criteria.

Evaluation of the Protective Effects of Alpha Lipoic Acid on Bleomycin-Induced Ovarian Toxicity

Chemotherapeutic drugs administered during cancer therapy, may lead to the depletion of ovarian follicles, and subsequent infertility in fertile patients. We aimed to determine toxic effects of bleomycin (BLM) on rat ovary, and to evaluate protective effects of alpha lipoic acid (ALA) on BLM toxicity. The total of 30 adult female rats were split into 4 groups. First, an intramuscular injection (i.m) of BLM (30 mg/m2) was administered to BLM and BLM + ALA groups except the control and ALA groups on the 1st, 8th and 15th days. The control group received 0.1 mL (i.m) saline on those days. BLM + ALA group received ALA (50 mg/kg) subcutaneously (s.c) for 2 weeks at the same time with BLM injections, and ALA group received ALA s.c for the same period. Ovarian tissues were evaluated by histopathological, stereological, immunohistochemical (StAR, VDAC2, Caspase-3, Bcl-2, and expression levels) and ELISA (AMH serum levels) methods. The vascular areas and collagen density increased in the medulla, and the volumes of medulla, cortex, and total ovary increased in BLM group, whereas these changes decreased in BLM + ALA group. On the other hand, VDAC2 and Caspase-3 expressions decreased, StAR and Bcl-2 expressions increased in BLM group, whereas VDAC2 and Caspase-3 expressions increased, and StAR and Bcl-2 expression levels significantly decreased in BLM + ALA group. Besides, follicle number and AMH levels decreased in the BLM group, but remarkably increased in the BLM + ALA group. We established that ALA may have ameliorative effects on the harmful effects of BLM on ovary.

Female Sexual Health and Cancer

As the majority of female cancer survivors can now expect to live long lives beyond cancer diagnosis and treatment, there is a growing need to address the significant late effects of treatment. Unfortunately, sexual health remains a primary concern that often goes unaddressed among female cancer survivors. Sexual dysfunction is one of the most common and distressing effects of treatment. Management of issues related to sexual health and sexual function depends upon the type of malignancy, stage and other tumor characteristics, treatment, and the history, concerns, and goals of the individual patient.

Metformin protects prepubertal mice ovarian reserve against cyclophosphamide via regulation of the PI3K/Akt/mTOR signaling pathway and Yap-1

BACKGROUND

Cyclophosphamide is a widely utilized chemotherapeutic agent for pediatric cancers, known to elicit adverse effects, including perturbation of the PI3K/Akt/mTOR and Hippo signaling pathways, thereby diminishing ovarian reserve and fertility potential in females. Consequently, this investigation delves into the mitigative effects of metformin on cyclophosphamide-induced ovarian impairment in prepubertal mice.

METHODS

Twenty-four 14-day-old NMRI female mice were distributed into four groups: Control (Cont), Cyclophosphamide (Cyc), Metformin (Met), and Metformin plus Cyclophosphamide (Met-Cyc). The Met-Cyc group was given daily doses of 150 mg/kg metformin for 11 consecutive days and in parallel 3 intermittent doses of 65 mg/kg cyclophosphamide once every three days. The Met and Cyc groups were given identical doses of Met or Cyc alone. The control group received normal saline treatment. On the 12th day, mice were sacrificed for analysis. Stereological methods were employed to measure the overall volume of the ovaries, including the medulla, cortex, and follicles, along with measuring anti-Müllerian hormone (AMH) levels using an ELISA kit. Furthermore, qRT-PCR was utilized to quantify the expression levels of genes, including P53, Bax, Bcl-2, Rad-51, Pten, Mtor, and Yap-1.

RESULTS

The findings demonstrate that metformin ameliorates cyclophosphamide-induced ovarian toxicity by increasing AMH levels and attenuating the excessive activation of primordial follicles, the ratio of growing to quiescent follicles, and follicular atresia. This protective effect is mediated by the downregulation of apoptosis-related genes, upregulation of the gene involved in a reparative pathway, and modulation of the PI3K/Akt/mTOR pathway evidenced by increased expression of Pten, Mtor and Hippo pathway by Yap-1 expression.

CONCLUSIONS

Our results advocate for the potential of metformin as a viable therapeutic option for preserving ovarian function in cyclophosphamide-treated adolescent girls, given its favorable side effect profile and ability to improve cyclophosphamide-induced ovarian damage.

MSCs-derived EVs protect against chemotherapy-induced ovarian toxicity: role of PI3K/AKT/mTOR axis

Chemotherapy detrimentally impacts fertility via depletion of follicular reserves in the ovaries leading to ovarian failure (OF) and development of estrogen deficiency-related complications. The currently proposed options to preserve fertility such as Oocyte or ovarian cortex cryopreservation are faced with many technical obstacles that limit their effective implementation. Therefore, developing new modalities to protect ovarian function remains a pending target. Exosomes are nano-sized cell-derived extracellular vesicles (EVs) with documented efficacy in the field of regenerative medicine. The current study sought to determine the potential beneficial effects of mesenchymal stem cells (MSCs)-derived EVs in experimentally induced OF. Female albino rats were randomly allocated to four groups: control, OF group, OF + MSCs-EVs group, OF + Rapamycin (mTOR inhibitor) group, and OF + Quercetin (PI3K/AKT inhibitor) group. Follicular development was assessed via histopathological and immunohistochemical examination, and ovarian function was evaluated by hormonal assay. PI3K/Akt/mTOR signaling pathway as a key modulator of ovarian follicular activation was also assessed. MSCs-EVs administration to OF rats resulted in restored serum hormonal levels, preserved primordial follicles and oocytes, suppressed ovarian PI3K/AKT axis and downstream effectors (mTOR and FOXO3), modulated miRNA that target this axis, decreased expression of ovarian apoptotic markers (BAX, BCl2) and increased expression of proliferation marker Ki67. The present study validated the effectiveness of MSCs-EVs therapy in preventing ovarian insufficiency induced by chemotherapy. Concomitant MSCs-EVs treatment during chemotherapy could significantly preserve ovarian function and fertility by suppressing the PI3K/Akt axis, preventing follicular overactivation, maintaining normal ovarian cellular proliferation, and inhibiting granulosa cell apoptosis.

Human umbilical cord mesenchymal stem cells restore chemotherapy-induced premature ovarian failure by inhibiting ferroptosis in vitro ovarian culture system

BACKGROUND

Mesenchymal stem cells (MSCs) have shown potential in repairing chemotherapy-induced premature ovarian failure (POF). However, challenges such as stem cell loss and immune phagocytosis post-transplantation hinder their application. Due to easy and safe handling, in vitro ovarian culture is widely available for drug screening, pathophysiological research, and in vitro fertilization. MSCs could exhibit therapeutic capacity for ovarian injury, and avoid stem cell loss and immune phagocytosis in vitro tissue culture system. Therefore, this study utilizes an in vitro ovarian culture system to investigate the reparative potential of human umbilical cord mesenchymal stem cells (hUCMSCs) and their mechanism.

METHODS

In this study, a chemotherapy-induced POF model was established by introducing cisplatin in vitro ovarian culture system. The reparative effects of hUCMSCs on damaged ovarian tissue were validated through Transwell chambers. Tissue histology examination, immunohistochemical staining, Western blotting, and RT-PCR were employed to evaluate the expression effects of hUCMSCs on ferroptosis and fibrosis-related genes during the process of repairing cisplatin-induced POF.

RESULTS

Cisplatin was found to activate ovarian follicles in vitro POF model. Transcriptomic sequencing analysis revealed that cisplatin could activate genes associated with ferroptosis. hUCMSCs alleviated cisplatin-induced POF by suppressing the expression of ferroptosis. Moreover, inhibiting ferroptosis by hUCMSCs also ameliorated ovarian hormone levels and reduced the expression of fibrosis-related factors α-SMA and COL-I in the ovaries.

CONCLUSIONS

This study confirms that cisplatin-induced ovarian damage via ferroptosis in vitro POF model, and hUCMSCs repair ovarian injury by inhibiting the ferroptosis pathway and suppressing fibrosis. This research contributes to evaluating the effectiveness of hUCMSCs in treating chemotherapy-induced POF by inhibiting ferroptosis in an in vitro ovarian culture system and provides a potential therapeutic strategy for chemotherapy-induced POF.

Nur77 ameliorates cyclophosphamide-induced ovarian insufficiency in mice by inhibiting oxidative damage and cell senescence

Premature ovarian failure (POF) is among the primary causes of ovarian dysfunction that severely affects women's physical and mental health. The main purpose of this study was to explore the expression level of Nerve growth factor-induced protein B (Nur77/NR4A1) in cyclophosphamide (CTX)-induced POF. We then tested whether Nur77 can exert a protective effect after CTX treatment and investigated the mechanism of Nur77's role during ovarian injury. CTX promotes follicular atresia by inducing redox imbalance, apoptosis, and senescence, thereby causing direct toxicity to gonads. Additionally, CTX decreases ovarian reserve consumption by stimulating the excessive activation of primordial follicles. Nur77 can be stimulated by oxidative stress, DNA damage, metabolism, inflammation, etc. However, its relationship with POF remains unelucidated. We here found that Nur77 is expressed at low levels in POF ovaries. Therefore, Nur77 was identified as a regulator of ovarian injury and follicular development. According to the results, Nur77 overexpression alleviated redox imbalances, reduced cell senescence and apoptosis, and improved follicular reserve. Nur77 protects ovarian function by restoring disordered sex hormone levels and estrus cycles and promoting follicle growth and development at all levels. Moreover, the rapamycin protein kinase (AKT)/mammalian target of the rapamycin (mTOR) is a crucial regulator of the primordial follicle pool and follicular development. A relationship was observed between Nur77 and AKT through string and molecular docking. Experiments confirmed the involvement of the AKT/mTOR signaling pathway in the regulatory role of Nur77 in ovarian function. Thus, Nur77 is a critical target for POF prevention and treatment.

The role of declining ataxia-telangiectasia-mutated (ATM) function in oocyte aging

Despite the advances in the understanding of reproductive physiology, the mechanisms underlying ovarian aging are still not deciphered. Recent research found an association between impaired ATM-mediated DNA double-strand break (DSB) repair mechanisms and oocyte aging. However, direct evidence connecting ATM-mediated pathway function decline and impaired oocyte quality is lacking. The objective of this study was to determine the role of ATM-mediated DNA DSB repair in the maintenance of oocyte quality in a mouse oocyte knockdown model. Gene interference, in vitro culture, parthenogenesis coupled with genotoxicity assay approaches, as well as molecular cytogenetic analyses based upon next-generation sequencing, were used to test the hypothesis that intact ATM function is critical in the maintenance of oocyte quality. We found that ATM knockdown impaired oocyte quality, resulting in poor embryo development. ATM knockdown significantly lowered or blocked the progression of meiosis in vitro, as well as retarding and reducing embryo cleavage after parthenogenesis. After ATM knockdown, all embryos were of poor quality, and none reached the blastocyst stage. ATM knockdown was also associated with an increased aneuploidy rate compared to controls. Finally, ATM knockdown increased the sensitivity of the oocytes to a genotoxic active metabolite of cyclophosphamide, with increased formation of DNA DSBs, reduced survival, and earlier apoptotic death compared to controls. These findings suggest a key role for ATM in maintaining oocyte quality and resistance to genotoxic stress, and that the previously observed age-induced decline in oocyte ATM function may be a prime factor contributing to oocyte aging.

De novo design of a nanoregulator for the dynamic restoration of ovarian tissue in cryopreservation and transplantation

The cryopreservation and transplantation of ovarian tissue underscore its paramount importance in safeguarding reproductive capacity and ameliorating reproductive disorders. However, challenges persist in ovarian tissue cryopreservation and transplantation (OTC-T), including the risk of tissue damage and dysfunction. Consequently, there has been a compelling exploration into the realm of nanoregulators to refine and enhance these procedures. This review embarks on a meticulous examination of the intricate anatomical structure of the ovary and its microenvironment, thereby establishing a robust groundwork for the development of nanomodulators. It systematically categorizes nanoregulators and delves deeply into their functions and mechanisms, meticulously tailored for optimizing ovarian tissue cryopreservation and transplantation. Furthermore, the review imparts valuable insights into the practical applications and obstacles encountered in clinical settings associated with OTC-T. Moreover, the review advocates for the utilization of microbially derived nanomodulators as a potent therapeutic intervention in ovarian tissue cryopreservation. The progression of these approaches holds the promise of seamlessly integrating nanoregulators into OTC-T practices, thereby heralding a new era of expansive applications and auspicious prospects in this pivotal domain.

Cancer and Female Sexual Function

Sexual health is a concern that often goes unaddressed among female cancer survivors. Management of these issues depends upon the type of malignancy, stage and other tumor characteristics, treatment, and the history, concerns, and goals of the individual patient.

Research progress on the prevention and treatment of chemotherapy-induced ovarian damage

Chemotherapy is a main treatment option for malignant tumors, but it may cause various adverse effects, including dysfunction of female endocrine system and fertility. Chemotherapy-induced ovarian damage has been concerned with ovarian preservation but also the prevention and treatment of ovarian dysfunction. In this article, the mechanisms of ovarian injury caused by chemotherapy, including apoptosis of the follicle and supporting cells, follicle "burn out", ovarian stromal and microvascular damage; and influencing factors, including age at diagnosis, initial low pre-treatment anti-Müllerian hormone levels, toxicity, dose and regimen of chemotherapy drugs are reviewed based on the latest research results and clinical practice. The article also discusses measures and frontier therapies for the prevention and treatment of ovarian injury, including the application of gonadotropin releasing hormone agonists or antagonists, tyrosine kinase inhibitors, antioxidants, sphingosine-1-phosphate, ceramide-1-phosphate, mammalian target of rapamycin inhibitors, granulocyte-colony stimulating factor, stem cell therapy and artificial ovaries.

Cellular senescence in the pathogenesis of ovarian dysfunction

The follicular microenvironment is crucial for normal ovarian function, and intra-ovarian factors, in coordination with gonadotropins, contribute to its regulation. Recent research has revealed that the accumulation of senescent cells worsens the adverse environment of various tissues and plays critical roles in chronological aging and various pathological conditions. Cellular senescence involves cell-cycle arrest, a senescence-associated secretory phenotype (SASP), macromolecular damage, and dysmetabolism. In this review, I summarize the latest knowledge regarding the role of cellular senescence in pathological conditions in the ovary, in the context of reproduction. Specifically, cellular senescence is known to impair follicular and oocyte health in cisplatin- and cyclophosphamide-induced primary ovarian insufficiency and to contribute to the pathogenesis of polycystic ovary syndrome (PCOS). In addition, cellular senescence is induced during the decline in ovarian reserve that is associated with chronological aging, endometriosis, psychological stress, and obesity, but it remains unclear whether it plays a causative role in these conditions. Finally, I discuss the potential for use of cellular senescence as a novel therapeutic target. The modification of SASP using a senomorphic and/or the elimination of senescent cells using a senolytic represent promising therapeutic strategies. Further elucidation of the role of cellular senescence in the effects of various insults on ovarian reserve, including chronological aging, as well as in pathogenesis of ovarian pathologies, including PCOS, may facilitate a new era of reproductive medicine.

Study on the effects and mechanisms of Wenzhong Bushen Formula in improving ovarian reserve decline in mice based on network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

The Wenzhong Bushen Formula (WZBSF) is a traditional Chinese medicine empirical formula known for its effects in tonifying qi, strengthening the spleen, warming the kidneys, promoting yang, regulating blood circulation, and balancing menstruation. Clinical evidence has demonstrated its significant efficacy in treating Diminished Ovarian Reserve (DOR) by improving ovarian reserves. However, the specific pharmacological mechanisms of WZBSF remain unclear.

AIM OF THE STUDY

This study aims to investigate the mechanisms by which WZBSF improves ovarian reserve decline through network pharmacology and animal experiments.

METHODS AND MATERIALS

WZBSF was analyzed using a dual UPLC-MS/MS and GC-MS platform. Effective components and targets of WZBSF were obtained from the TCMSP database and standardized using UniProt. Disease targets were collected from GeneCard, OMIM, PHARMGKB, and DisGeNET databases, with cross-referencing between the two sets of targets. A PPI protein interaction network was constructed using Cytoscape3.9.1 and STRING database, followed by KEGG and GO enrichment analysis using the Metascape database. Finally, an ovarian reserve decline model was established in mice, different doses of WZBSF were administered, and experimental validation was conducted through serum hormone detection, H&E staining, immunofluorescence (IF), immunohistochemistry (IHC), and Western blot analysis (WB).

RESULTS

WZBSF shares 145 common targets with ovarian reserve decline. GO enrichment analysis revealed involvement in biological processes such as response to hormone stimulation and phosphatase binding, while KEGG analysis implicated pathways including the PI3K-AKT signaling pathway and FoxO signaling pathway. In mice with ovarian reserve decline, WZBSF restored weight gain rate, increased ovarian index, normalized estrous cycles, reversed serum hormone imbalances, restored various follicle counts, and improved ovarian morphology. Additionally, WZBSF reduced p-AKT and p-FOXO3a levels, preventing excessive activation of primordial follicles and maintaining ovarian reserve.

CONCLUSION

WZBSF can ameliorate cyclophosphamide and busulfan-induced ovarian reserve decline, and its mechanism may be associated with the inhibition of the PI3K/AKT/FOXO3a signaling pathway.

The potent paracrine effect of umbilical cord mesenchymal stem cells mediates mitochondrial quality control to restore chemotherapy-induced damage in ovarian granulosa cells

The basic principle of chemotherapy is to attack cells with fast growth, and cancer cells are targeted by anticancer drugs because they have a faster growth rate than normal cells. High doses of anticancer drugs may cause an irreversible decline in reproductive capacity, and novel approaches for fertility preservation and/or restoration after anticancer treatment are urgently needed. Here, we provide important insights into the recovery of human reproductive cells damaged by chemotherapy. We performed a detailed screening of the cytokines of various human mesenchymal stem cells (hMSCs) to select superior MSCs. Also, we analyzed the Ovarian granulosa cell (OGC)-)-specific functions for restoring function, apoptosis, and mitochondrial functions to confirm the recovery mechanism in damaged OGCs. As a result, we demonstrated that conditioned media (CM) of Umbilical cord mesenchymal stem cells (UC-MSCs) could restore the functions of damaged OGCs primarily through antiapoptotic and antioxidant effects. Furthermore, CM changed the phenotype of damaged OGCs to an energetic status by restoring mitochondrial function and enhanced the mitochondrial metabolic activity decreased by chemotherapy. Finally, we demonstrated that the restoration of mitochondrial function in damaged OGCs was mediated through mitochondrial autophagy (mitophagy). Our findings offer new insights into the potential of stem cell-based therapy for fertility preservation and/or restoration in female cancer patients.

Genitourinary Syndrome of Menopause in Cancer Survivors

Genitourinary syndrome of menopause (GSM) encompasses the symptoms of estrogen deprivation in the vaginal, vulva, and bladder areas. Because many cancer treatments induce a hypoestrogenic state, GSM is common in cancer survivors. The number of cancer survivors is increasing, and the unique aspects of GSM management for cancer survivors, such as the safety of hormonal therapies, is important to understand. In this review, we cover important considerations in the assessment of GSM; nonpharmacologic, behavioral, integrative, pharmacologic, and medical device treatments for GSM: the unique considerations in GSM by cancer treatment modality; bladder manifestations of GSM; and GSM in specific populations.

Subsequent ovarian yolk sac tumor after operation of ovarian mature teratoma: a case report and review of the literature

Ovarian mature teratoma represents a benign ovarian tumor, while ovarian yolk sac tumor (YST, endodermal sinus tumor) is a rare malignant tumor predominantly affecting young women, often associated with a grim prognosis post-metastasis. Both ovarian mature teratoma and ovarian YST are germ cell tumors. There are few studies on the correlation between ovarian YST and mature teratoma. Recurrence or malignant transformation may occur following the surgical intervention for ovarian mature teratoma. However, the occurrence of YST subsequent to such procedures is notably rare. In this investigation, we reported a case involving a 24-year-old unmarried woman with both mature ovarian teratoma and YST within a brief 1-year interval. Regular reexamination protocols facilitated the early-stage detection of YST. The patient underwent surgical treatment, chemotherapy, and measures to preserve ovarian function, resulting in a favorable prognosis. Our primary purpose is to distill clinical insights from the diagnostic and therapeutic journey of this patient. Our purpose is to enhance medical professionals' awareness that YST may be secondary to mature teratoma. Additionally, we underscore the critical importance of routine postoperative surveillance for ovarian mature teratoma, emphasizing its pivotal role in early malignant tumor detection-a factor paramount to the prognosis of patients.

The Role of Cellular Senescence in Cyclophosphamide-Induced Primary Ovarian Insufficiency

Young female cancer patients can develop chemotherapy-induced primary ovarian insufficiency (POI). Cyclophosphamide (Cy) is one of the most widely used chemotherapies and has the highest risk of damaging the ovaries. Recent studies elucidated the pivotal roles of cellular senescence, which is characterized by permanent cell growth arrest, in the pathologies of various diseases. Moreover, several promising senolytics, including dasatinib and quercetin (DQ), which remove senescent cells, are being developed. In the present study, we investigated whether cellular senescence is involved in Cy-induced POI and whether DQ treatment rescues Cy-induced ovarian damage. Expression of the cellular senescence markers p16, p21, p53, and γH2AX was upregulated in granulosa cells of POI mice and in human granulosa cells treated with Cy, which was abrogated by DQ treatment. The administration of Cy decreased the numbers of primordial and primary follicles, with a concomitant increase in the ratio of growing to dormant follicles, which was partially rescued by DQ. Moreover, DQ treatment significantly improved the response to ovulation induction and fertility in POI mice by extending reproductive life. Thus, cellular senescence plays critical roles in Cy-induced POI, and targeting senescent cells with senolytics, such as DQ, might be a promising strategy to protect against Cy-induced ovarian damage.

Facilitation of Ovarian Response by Mechanical Force-Latest Insight on Fertility Improvement in Women with Poor Ovarian Response or Primary Ovarian Insufficiency

The decline in fertility in aging women, especially those with poor ovarian response (POR) or primary ovarian insufficiency (POI), is a major concern for modern IVF centers. Fertility treatments have traditionally relied on gonadotropin- and steroid-hormone-based IVF practices, but these methods have limitations, especially for women with aging ovaries. Researchers have been motivated to explore alternative approaches. Ovarian aging is a complicated process, and the deterioration of oocytes, follicular cells, the extracellular matrix (ECM), and the stromal compartment can all contribute to declining fertility. Adjunct interventions that involve the use of hormones, steroids, and cofactors and gamete engineering are two major research areas aimed to improve fertility in aging women. Additionally, mechanical procedures including the In Vitro Activation (IVA) procedure, which combines pharmacological activators and fragmentation of ovarian strips, and the Whole Ovary Laparoscopic Incision (WOLI) procedure that solely relies on mechanical manipulation in vivo have shown promising results in improving follicle growth and fertility in women with POR and POI. Advances in the use of mechanical procedures have brought exciting opportunities to improve fertility outcomes in aging women with POR or POI. While the lack of a comprehensive understanding of the molecular mechanisms that lead to fertility decline in aging women remains a major challenge for further improvement of mechanical-manipulation-based approaches, recent progress has provided a better view of how these procedures promote folliculogenesis in the fibrotic and avascular aging ovaries. In this review, we first provide a brief overview of the potential mechanisms that contribute to ovarian aging in POI and POR patients, followed by a discussion of measures that aim to improve ovarian folliculogenesis in aging women. At last, we discuss the likely mechanisms that contribute to the outcomes of IVA and WOLI procedures and potential future directions.

Gold nanoparticles and gold nanorods in the landscape of cancer therapy

Cancer is a grievous disease whose treatment requires a more efficient, non-invasive therapy, associated with minimal side effects. Gold nanoparticles possessing greatly impressive optical properties have been a forerunner in bioengineered cancer therapy. This theranostic system has gained immense popularity and finds its application in the field of molecular detection, biological imaging, cancer cell targeting, etc. The photothermal property of nanoparticles, especially of gold nanorods, causes absorption of the light incident by the light source, and transforms it into heat, resulting in tumor cell destruction. This review describes the different optical features of gold nanoparticles and summarizes the advance research done for the application of gold nanoparticles and precisely gold nanorods for combating various cancers including breast, lung, colon, oral, prostate, and pancreatic cancer.

Chemotherapy impairs ovarian function through excessive ROS-induced ferroptosis

Chemotherapy was conventionally applied to kill cancer cells, but regrettably, they also induce damage to normal cells with high-proliferative capacity resulting in cardiotoxicity, nephrotoxicity, peripheral nerve toxicity, and ovarian toxicity. Of these, chemotherapy-induced ovarian damages mainly include but are not limited to decreased ovarian reserve, infertility, and ovarian atrophy. Therefore, exploring the underlying mechanism of chemotherapeutic drug-induced ovarian damage will pave the way to develop fertility-protective adjuvants for female patients during conventional cancer treatment. Herein, we firstly confirmed the abnormal gonadal hormone levels in patients who received chemotherapy and further found that conventional chemotherapeutic drugs (cyclophosphamide, CTX; paclitaxel, Tax; doxorubicin, Dox and cisplatin, Cis) treatment significantly decreased both the ovarian volume of mice and the number of primordial and antral follicles and accompanied with the ovarian fibrosis and reduced ovarian reserve in animal models. Subsequently, Tax, Dox, and Cis treatment can induce the apoptosis of ovarian granulosa cells (GCs), likely resulting from excessive reactive oxygen species (ROS) production-induced oxidative damage and impaired cellular anti-oxidative capacity. Thirdly, the following experiments demonstrated that Cis treatment could induce mitochondrial dysfunction through overproducing superoxide in GCs and trigger lipid peroxidation leading to ferroptosis, first reported in chemotherapy-induced ovarian damage. In addition, N-acetylcysteine (NAC) treatment could alleviate the Cis-induced toxicity in GCs by downregulating cellular ROS levels and enhancing the anti-oxidative capacity (promoting the expression of glutathione peroxidase, GPX4; nuclear factor erythroid 2-related factor 2, Nrf2 and heme oxygenase-1, HO-1). Our study confirmed the chemotherapy-induced chaotic hormonal state and ovarian damage in preclinical and clinical examination and indicated that chemotherapeutic drugs initiated ferroptosis in ovarian cells through excessive ROS-induced lipid peroxidation and mitochondrial dysfunction, leading to ovarian cell death. Consequently, developing fertility protectants from the chemotherapy-induced oxidative stress and ferroptosis perspective will ameliorate ovarian damage and further improve the life quality of cancer patients.

The Impact of Systemic Oncological Treatments on the Fertility of Adolescents and Young Adults-A Systematic Review

BACKGROUND

Over the past decades, advancements in oncological treatments have led to major improvements in survival. Particularly for adolescents and young adults (AYAs), fertility is an important concern in cancer survivorship. The purpose of the review is to provide physicians with a practical overview of the current knowledge about the impact of systemic oncological treatments on the fertility of female and male AYAs.

METHODS

A systematic review was performed based on relevant articles obtained from 4 databases up until 31 December 2022.

RESULTS

The mechanisms of gonadotoxicity and the concurrent risk is described for the following categories: chemotherapy, targeted therapy and immunotherapy. For the category "chemotherapy", the specific effects and risks are listed for the different classes and individual chemotherapeutics. In the category "targeted therapy", a distinction was made between tyrosine kinase inhibitors (TKIs) and monoclonal antibodies. Information concerning immunotherapy is scarce.

CONCLUSIONS

The effects of chemotherapy on fertility are well investigated, but even in this category, results can be conflicting. Insufficient data are available on the fertility effects of targeted therapy and immunotherapy to draw definitive conclusions. More research is needed for these therapies and their evolving role in treating cancers in AYAs. It would be useful to include fertility endpoints in clinical trials that evaluate new and existing oncological treatments.

Chemotherapy induced oxidative stress in the ovary: drug-dependent mechanisms and potential interventions†

Cancer incidence and relative survival are expected to increase over the next few decades. With the majority of patients receiving combinatorial chemotherapy, an increasing proportion of patients experience long-term side effects from treatment-including reproductive disorders and infertility. A limited number of studies have examined mechanisms of single-agent chemotherapy-induced gonadotoxicity, with chemotherapy-induced oxidative stress being implicated in the loss of reproductive functions. Current methods of female fertility preservation are costly, invasive, only moderately successful, and seldom presented to cancer patients. The potential of antioxidants to alleviate chemotherapy has been overlooked at a time when it is becoming increasingly important to develop strategies to protect reproductive functions during chemotherapy. This review will summarize the importance of reactive oxygen species homeostasis in reproduction, chemotherapy-induced mitochondrial dysfunction in oocytes, chemotherapy-induced oxidative stress, and several promising natural adjuvants.

The future of fertility preservation for women treated with chemotherapy

Cytotoxic chemotherapies have been a mainstay of cancer treatment, but are associated with numerous systemic adverse effects, including impacts to fertility and endocrine health. Irreversible ovarian damage and follicle depletion are side-effects of chemotherapy that can lead to infertility and premature menopause, both being major concerns of young cancer patients. Notably, many women will proceed with fertility preservation, but unfortunately existing strategies don't entirely solve the problem. Most significantly, oocyte and embryo freezing do not prevent cancer treatment-induced ovarian damage from occurring, which may result in the impairment of long-term hormone production. Unfortunately, loss of endogenous endocrine function is not fully restored by hormone replacement therapy. Additionally, while GnRH agonists are standard care for patients receiving alkylating chemotherapy to lessen the risk of premature menopause, their efficacy is incomplete. The lack of more broadly effective options stems, in part, from our poor understanding of how different treatments damage the ovary. Here, we summarise the impacts of two commonly utilised chemotherapies - cyclophosphamide and cisplatin - on ovarian function and fertility, and discuss the mechanisms underpinning this damage. Additionally, we critically analyse current research avenues in the development of novel fertility preservation strategies, with a focus on fertoprotective agents.

TAp63 determines the fate of oocytes against DNA damage

Cyclophosphamide and doxorubicin lead to premature ovarian insufficiency as an off-target effect. However, their oocyte death pathway has been debated. Here, we clarified the precise mechanism of ovarian depletion induced by cyclophosphamide and doxorubicin. Dormant oocytes instead of activated oocytes with high PI3K activity were more sensitive to cyclophosphamide. Checkpoint kinase 2 (CHK2) inhibitor rather than GNF2 protected oocytes from cyclophosphamide and doxorubicin, as cyclophosphamide up-regulated p-CHK2 and depleted primordial follicles in Abl1 knockout mice. Contrary to previous reports, TAp63 is pivotal in cyclophosphamide and doxorubicin-induced oocyte death. Oocyte-specific Trp63 knockout mice prevented primordial follicle loss and maintained reproductive function from cyclophosphamide and doxorubicin, indicated by undetectable levels of BAX and cPARP. Here, we demonstrated that TAp63 is fundamental in determining the signaling of oocyte death against DNA damage. This study establishes the role of TAp63 as a target molecule of adjuvant therapies to protect the ovarian reserve from different classes of chemotherapy.

Microencapsulation and nanowarming enables vitrification cryopreservation of mouse preantral follicles

Preantral follicles are often used as models for cryopreservation and in vitro culture due to their easy availability. As a promising approach for mammalian fertility preservation, vitrification of preantral follicles requires high concentrations of highly toxic penetrating cryoprotective agents (up to 6 M). Here, we accomplish low-concentration-penetrating cryoprotective agent (1.5 M) vitrification of mouse preantral follicles encapsulated in hydrogel by nanowarming. We find that compared with conventional water bath warming, the viability of preantral follicles is increased by 33%. Moreover, the cavity formation rate of preantral follicles after in vitro culture is comparable to the control group without vitrification. Furthermore, the percentage of MII oocytes developed from the vitrified follicles, and the birth rate of offspring following in vitro fertilization and embryo transfer are also similar to the control group. Our results provide a step towards nontoxic vitrification by utilizing the synergistic cryoprotection effect of microencapsulation and nanowarming.

Oocyte Quiescence: From Formation to Awakening

Decades of work using various model organisms have resulted in an exciting and emerging field of oocyte maturation. High levels of insulin and active mammalian target of rapamycin signals, indicative of a good nutritional environment, and hormones such as gonadotrophin, indicative of the growth of the organism, work together to control oocyte maturation to ensure that reproduction happens at the right timing under the right conditions. In the wild, animals often face serious challenges to maintain oocyte quiescence under long-term unfavorable conditions in the absence of mates or food. Failure to maintain oocyte quiescence will result in activation of oocytes at the wrong time and thus lead to exhaustion of the oocyte pool and sterility of the organism. In this review, we discuss the shared mechanisms in oocyte quiescence and awakening and a conserved role of noradrenergic signals in maintenance of the quiescent oocyte pool under unfavorable conditions in simple model organisms.

Fertility after Cancer: Risks and Successes

The incidence of cancer in reproductive-aged women is 7%, but, despite the increased number of cancer cases, advances in early diagnosis and treatment have raised the survival rate. Furthermore, in the last four decades, there has been a rising trend of delaying childbearing. There has been an increasing number of couples referred to Reproductive Medicine Centers for infertility problems after one partner has been treated for cancer. In these cases, the main cause of reduced fertility derives from treatments. In this review, we describe the effects and the risks of chemotherapy, radiotherapy, and surgery in women with cancer, and we will focus on available fertility preservation techniques and their efficacy in terms of success in pregnancy and live birth rates.

A Warning Call for Fertility Preservation Methods for Women Undergoing Gonadotoxic Cancer Treatment

Malignant hematological conditions have recognized an increased incidence and require aggressive treatments. Targeted chemotherapy, accompanied or not by radiotherapy, raises the chance of defeating the disease, yet cancer protocols often associate long-term gonadal consequences, for instance, diminished or damaged ovarian reserve. The negative effect is directly proportional to the types, doses, time of administration of chemotherapy, and irradiation. Additionally, follicle damage depends on characteristics of the disease and patient, such as age, concomitant diseases, previous gynecological conditions, and ovarian reserve. Patients should be adequately informed when proceeding to gonadotoxic therapies; hence, fertility preservation should be eventually regarded as a first-intention procedure. This procedure is most beneficial when performed before the onset of cancer treatment, with the recommendation for embryos or oocytes’ cryopreservation. If not feasible or acceptable, several options can be available during or after the cancer treatment. Although not approved by medical practice, promising results after in vitro studies increase the chances of future patients to protect their fertility. This review aims to emphasize the mechanism of action and impact of chemotherapy, especially the one proven to be gonadotoxic, upon ovarian reserve and future fertility. Reduced fertility or infertility, as long-term consequences of chemotherapy and, particularly, following bone marrow transplantation, is often associated with a negative impact of recovery, social and personal life, as well as highly decreased quality of life.

Female Oncofertility: Current Understandings, Therapeutic Approaches, Controversies, and Future Perspectives

Recent advances in early detection and oncological therapies have ameliorated the survival rate of young cancer patients. Yet, ovarian impairment induced by chemotherapy and radiotherapy is still a challenging issue. This review, based on clinical and lab-based studies, summarizes the evidence of gonadotoxicity of chemoradiotherapy, the recent approaches, ongoing controversies, and future perspectives of fertility preservation (FP) in female patients who have experienced chemo- or radio-therapy. Existing data indicate that chemotherapeutic agents induce DNA alterations and massive follicle activation via the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway. Meanwhile, the radiation causes ionizing damage, leading to germ cell loss. In addition to the well-established methods, numerous therapeutic approaches have been suggested, including minimizing the follicle loss in cryopreserved ovarian grafts after transplantation, in vitro activation or in vitro growing of follicles, artificial ovarian development, or fertoprotective adjuvant to prevent ovarian damage from chemotherapy. Some reports have revealed positive outcomes from these therapies, whereas others have demonstrated conflictions. Future perspectives are improving the live birth rate of FP, especially in patients with adverse ovarian reserve, eliminating the risk of malignancy reintroducing, and increasing society’s awareness of FP importance.

Zihuai recipe alleviates cyclophosphamide-induced diminished ovarian reserve via suppressing PI3K/AKT-mediated apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Zihuai recipe (ZHR), a Chinese herbal prescription, is widely used for the clinical treatment of Diminished ovarian reserve (DOR) infertility. However, little is known regarding its underlying mechanisms of DOR treatment.

AIM OF THE STUDY

This study aimed to investigate the beneficial effects of ZHR on the treatment of DOR and to reveal the underlying mechanisms.

MATERIALS AND METHODS

Sixty female 8-week-old Sprague-Dawley rats were randomly divided into the following six groups (n=10 per group): control, DOR, low-dose(2.7 g/kg/day) ZHR (L-ZHR), medium-dose(5.4 g/kg/day), ZHR (M-ZHR), high-dose(10.8 g/kg/day) ZHR (H-ZHR), and hormone replacement therapy (HRT) treatment groups. The DOR model was established in all the groups, except the control group, by a single intraperitoneal injection of 90 mg/kg cyclophosphamide. After the induction of the DOR model, rats were weighed and administered either the relevant dose of ZHR or an equal volume of saline solution (in the control and DOR groups). Rats in the HRT group received estradiol valerate tablets (0.16 mg/kg/day), and with medroxyprogesterone acetate tablets (0.86 mg/kg/day) added on day 4. After 32 days of treatment, the rats were euthanized and the ovaries were collected for sampling. Ovarian morphology was observed by hematoxylin and eosin staining and the number of follicles was counted under a microscope. The serum levels of anti-Müllerian hormone (AMH), gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) were quantified by ELISA. A TUNEL assay was used to analyze the level of apoptosis of the ovarian cells. The protein expressions of p-PI3K, p-AKT, PI3K, AKT, cleaved caspase-3, BAX, and Bcl-2 were measured by western blotting and immunohistochemistry. Data analysis was performed with SPSS 20.0 software.

RESULTS

ZHR administration increased the ovarian index and the serum levels of AMH, GnRH, and E2, while lowering those of FSH and LH. ZHR treatment also increased the number of primordial, primary, secondary, and antral follicles, as well as the number of corpora lutea, but decreased the number of atretic follicles. Furthermore, ZHR administration decreased the percentage of TUNEL-positive ovarian cells. After treatment with ZHR, the protein expression levels of p-PI3K/PI3K, p-AKT/AKT, cleaved caspase-3 and BAX were decreased, whereas the level of Bcl-2 was increased.

CONCLUSIONS

ZHR improved the ovarian reserve in CTX-induced DOR rats. The mechanisms of ZHR on DOR may be mediated through the regulation of gonadal hormones of the hypothalamic-pituitary-ovarian axis (HPOA), and the inhibition of PI3K/AKT-mediated apoptosis in granulosa cells.

Adipose-Derived Mesenchymal Stem Cell Transplantation in Chemotherapy-Induced Premature Ovarian Insufficiency: the Role of Connexin and Pannexin

In women undergoing chemotherapy, it is inevitable that infertility risk will increase because of impaired reproductive functions. Premature ovarian insufficiency (POI), which occurs as a devastating result of chemotherapy, is the complete depletion or dysfunction of ovarian follicles. Adipose-derived mesenchymal stem cells (ADMSCs) transplantation is among the alternative treatment methods for POI, which currently do not have an effective treatment method. Apoptosis of granulosa cells in POI is seen as the main mechanism of the disease. It is also reported that in addition to molecules directly associated with apoptosis, connexins, and pannexins are also potential effector molecules in apoptosis. The roles of these molecules in POI, which are known to play a role in many important mechanisms in the ovary, are unknown. In this study, it was aimed to analyze the expressions of Connexin43 and Pannexin1, which are thought to be effective in the formation of POI, and to show the relationship between the antiapoptotic effects of ADMSCs transplantation and these molecules in POI. For this purpose, Caspase3, Connexin43, Pannexin1 proteins, and mRNA expressions were analyzed by immunohistochemistry and RT-qPCR, and AMH levels were measured by ELISA. It was determined that Pannexin1, Caspase3 proteins, and mRNA levels increased in the POI, while Pannexin1 and Caspase3 expressions decreased in the ADMSCs treated group. While Connexin43 level decreased in POI, Connexin43 protein and mRNA levels increased in ADMSCs group. Consequently, this study demonstrated for the first time that Connexin43 and Pannexin1 were associated with apoptosis in POI. In addition, it was revealed that ADMSCs transplantation could produce antiapoptotic effects by modulating these molecules.

Molecular Mechanism and Prevention Strategy of Chemotherapy- and Radiotherapy-Induced Ovarian Damage

Fertility preservation is an emerging discipline, which is of substantial clinical value in the care of young patients with cancer. Chemotherapy and radiation may induce ovarian damage in prepubertal girls and young women. Although many studies have explored the mechanisms implicated in ovarian toxicity during cancer treatment, its molecular pathophysiology is not fully understood. Chemotherapy may accelerate follicular apoptosis and follicle reservoir utilization and damage the ovarian stroma via multiple molecular reactions. Oxidative stress and the radiosensitivity of oocytes are the main causes of gonadal damage after radiation treatment. Fertility preservation options can be differentiated by patient age, desire for conception, treatment regimen, socioeconomic status, and treatment duration. This review will help highlight the importance of multidisciplinary oncofertility strategies for providing high-quality care to young female cancer patients.

Current and Future Perspectives for Improving Ovarian Tissue Cryopreservation and Transplantation Outcomes for Cancer Patients

Although advances in cancer treatment and early diagnosis have significantly improved cancer survival rates, cancer therapies can cause serious side effects, including ovarian failure and infertility, in women of reproductive age. Infertility following cancer treatment can have significant adverse effects on the quality of life. However, established methods for fertility preservation, including embryo or oocyte cryopreservation, are not always suitable for female cancer patients because of complicated individual conditions and treatment methods. Ovarian tissue cryopreservation and transplantation is a promising option for fertility preservation in pre-pubertal girls and adult patients with cancer who require immediate treatment, or who are not eligible to undergo ovarian stimulation. This review introduces various methods and strategies to improve ovarian tissue cryopreservation and transplantation outcomes, to help patients and clinicians choose the best option when considering the potential complexity of a patient's situation. Effective multidisciplinary oncofertility strategies, involving the inclusion of a highly skilled and experienced oncofertility team that considers cryopreservation methods, thawing processes and devices, surgical procedures for transplantation, and advances in technologies, are necessary to provide high-quality care to a cancer patient.

Quercetin prevents primordial follicle loss via suppression of PI3K/Akt/Foxo3a pathway activation in cyclophosphamide-treated mice

BACKGROUND

Chemotherapy improves the survival rates of patients with various cancers but often causes some adverse effects, including ovarian damage, characterised by a decrease in primordial follicle stockpiles. Recent studies have revealed that chemotherapy may stimulate the PI3K signalling pathway, thereby resulting in accelerated primordial follicle activation and a decreased ovarian reserve. Quercetin is an inhibitor of the PI3K pathway; however, its protective effects against chemotherapy-induced follicle loss in mice have not been established. In this study, the effects of quercetin in a mouse model of cyclophosphamide-induced ovarian dysfunction were investigated.

METHODS

C57BL/6 female mice were used for the study. Paraffin sections of mouse ovaries (n = 30 mice) were stained with haematoxylin and eosin for differential follicle counts. Apoptosis (n = 5 mice per group) was evaluated by TUNEL assay. Immunohistochemical staining for ki67 and Foxo3a (n = 5 mice per group) was performed to evaluate the activation of primordial follicles. The role of the PI3K signalling pathway in the ovaries (n = 45 mice) was assessed by western blotting.

RESULTS

Quercetin attenuated the cyclophosphamide-induced reduction in dormant primordial follicles. Analysis of the PI3K/Akt/Foxo3a pathway showed that quercetin decreased the phosphorylation of proteins that stimulate follicle activation in cyclophosphamide-induced ovaries. Furthermore, quercetin prevented cyclophosphamide-induced apoptosis in early growing follicles and early antral follicles, maintained anti-Müllerian hormone levels secreted by these follicles, and preserved the quiescence of the primordial follicle pool, as determined by intranuclear Foxo3a staining.

CONCLUSIONS

Quercetin attenuates cyclophosphamide-induced follicle loss by preventing the phosphorylation of PI3K/Akt/Foxo3a pathway members and maintaining the anti-Müllerian hormone level through reduced apoptosis in growing follicles. Accordingly, quercetin is expected to improve fertility preservation and the prevention of endocrine-related side effects of chemotherapy.

Asciminib Mitigates DNA Damage Stress Signaling Induced by Cyclophosphamide in the Ovary

Cancer treatments can often adversely affect the quality of life of young women. One of the most relevant negative impacts is the loss of fertility. Cyclophosphamide is one of the most detrimental chemotherapeutic drugs for the ovary. Cyclophosphamide may induce the destruction of dormant follicles while promoting follicle activation and growth. Herein, we demonstrate the in vivo protective effect of the allosteric Bcr-Abl tyrosine kinase inhibitor Asciminib on signaling pathways activated by cyclophosphamide in mouse ovaries. We also provide evidence that Asciminib does not interfere with the cytotoxic effect of cyclophosphamide in Michigan Cancer Foundation (MCF)7 breast cancer cells. Our data indicate that concomitant administration of Asciminib mitigates the cyclophosphamide-induced ovarian reserve loss without affecting the anticancer potential of cyclophosphamide. Taken together, these observations are relevant for the development of effective ferto-protective adjuvants to preserve the ovarian reserve from the damaging effects of cancer therapies.

Metformin: a novel promising option for fertility preservation during cyclophosphamide-based chemotherapy

Cyclophosphamide (CP) could cause severe gonadotoxicity via imbalanced activation of primordial follicles through PI3K/AKT/mTOR activation. Whether metformin, a widely prescribed anti-diabetes agent with mTOR inhibitory effect, could preserve ovarian function against CP toxicity is unknown. Female C57BL/6 mice were randomized into seven groups (n = 11), including control, CP-alone, CP + metformin, CP + sirolimus or everolimus, metformin-alone and sirolimus-alone groups. The duration of pharmaceutical treatment was 4 weeks. CP treatment significantly impaired ovarian function and fertility in mice. CP + metformin treatment significantly attenuated the gonadotoxicity comparing to CP-alone treatment (primordial follicle count: 17.6 ± 4.2 versus 10.3 ± 2.7 follicles/high-power field; P = 0.027). CP + metformin treatment also tended to increase antral follicular count (5.4 ± 1.1 versus 2.5 ± 1.6 follicles/section), serum AMH levels (4.6 ± 1.2 versus 2.0 ± 0.8 ng/ml) and the litter size (4.2 ± 1.3 versus 1.5 ± 1.0 mice per pregnancy), compared with CP-alone group. Expression of phospho-mTOR and the number of TUNEL-positive granulosa cells increased after CP treatment and decreased in the CP + metformin groups, suggesting the mTOR inhibitory and anti-apoptotic effects of metformin. In in-vitro granulosa cell experiments, the anti-apoptotic effect of metformin was blocked after inhibiting p53 or p21 function, and the expression of p53 mRNA was blocked with AMPK inhibitor, suggesting that the anti-apoptotic effect was AMPK/p53/p21-mediated. In conclusion, concurrent metformin treatment during CP therapy could significantly preserve ovarian function and fertility and could be a promising novel fertility preserving agent during chemotherapy. The relatively acceptable cost and well-established long-term safety profiles of this old drug might prompt its further clinical application at a faster pace.

Individual-oocyte transcriptomic analysis shows that genotoxic chemotherapy depletes human primordial follicle reserve in vivo by triggering proapoptotic pathways without growth activation

Gonadotoxic chemotherapeutics, such as cyclophosphamide, can cause early menopause and infertility in women. Earlier histological studies showed ovarian reserve depletion via severe DNA damage and apoptosis, but others suggested activation of PI3K/PTEN/Akt pathway and follicle ‘burn-out’ as a cause. Using a human ovarian xenograft model, we performed single-cell RNA-sequencing on laser-captured individual primordial follicle oocytes 12 h after a single cyclophosphamide injection to determine the mechanisms of acute follicle loss after gonadotoxic chemotherapy. RNA-sequencing showed 190 differentially expressed genes between the cyclophosphamide- and vehicle-exposed oocytes. Ingenuity Pathway Analysis predicted a significant decrease in the expression of anti-apoptotic pro-Akt PECAM1 (p = 2.13E-09), IKBKE (p = 0.0001), and ANGPT1 (p = 0.003), and reduced activation of PI3K/PTEN/Akt after cyclophosphamide. The qRT-PCR and immunostaining confirmed that in primordial follicle oocytes, cyclophosphamide did not change the expressions of Akt (p = 0.9), rpS6 (p = 0.3), Foxo3a (p = 0.12) and anti-apoptotic Bcl2 (p = 0.17), nor affect their phosphorylation status. There was significantly increased DNA damage by γH2AX (p = 0.0002) and apoptosis by active-caspase-3 (p = 0.0001) staining in the primordial follicles and no change in the growing follicles 12 h after chemotherapy. These data support that the mechanism of acute follicle loss by cyclophosphamide is via apoptosis, rather than growth activation of primordial follicle oocytes in the human ovary.

Advances in the Treatment and Prevention of Chemotherapy-Induced Ovarian Toxicity

Due to improvements in chemotherapeutic agents, cancer treatment efficacy and cancer patient survival rates have greatly improved, but unfortunately gonadal damage remains a major complication. Gonadotoxic chemotherapy, including alkylating agents during reproductive age, can lead to iatrogenic premature ovarian insufficiency (POI), and loss of fertility. In recent years, the demand for fertility preservation has increased dramatically among female cancer patients. Currently, embryo and oocyte cryopreservation are the only established options for fertility preservation in women. However, there is growing evidence for other experimental techniques including ovarian tissue cryopreservation, oocyte in vitro maturation, artificial ovaries, stem cell technologies, and ovarian suppression. To prevent fertility loss in women with cancer, individualized fertility preservation options including established and experimental techniques that take into consideration the patient's age, marital status, chemotherapy regimen, and the possibility of treatment delay should be provided. In addition, effective multidisciplinary oncofertility strategies that involve a highly skilled and experienced oncofertility team consisting of medical oncologists, gynecologists, reproductive biologists, surgical oncologists, patient care coordinators, and research scientists are necessary to provide cancer patients with high-quality care.