No abstract

Chemotherapy is a widely used and effective adjuvant treatment for cancer, and it has unavoidable damage to female fertility, with statistics showing 38% of women who have received chemotherapy are infertile. How to reduce fertility toxicity while enhancing the oncologic chemotherapy is a clinical challenge. Herein, co‐delivery micelles (BML@PMP) are developed, which are composed of a reduction‐sensitive paclitaxel prodrug (PMP) for chemotherapy and a CHEK2 inhibitor (BML277) for both fertility protection and chemotherapy enhancement. BML@PMP achieves fertility protection through three actions: (1) Due to the enhanced permeability and retention (EPR) effect, BML@PMP is more enriched in the tumor, while very little in the ovary (about 1/10th of the tumor). (2) Glutathione (GSH) triggers the release of PTX, and with low levels of GSH in the ovary, the amount of PTX released in the ovary is correspondingly reduced. (3) BML277 inhibits oocyte apoptosis by inhibiting the CHEK2‐TAp63α pathway. Because of the different downstream targets of CHEK2 in tumor cells and oocytes, BML277 also enhances chemotherapeutic efficacy by reducing DNA damage repair which is activated through the CHEK2 pathway. This bidirectional effect of CHEK2 inhibitor‐based co‐delivery system represents a promising strategy for improving oncology treatment indices and preventing chemotherapy‐associated fertility damage.

Ovarian aging is characterized by a progressive decline in ovarian function. With the increase in life expectancy worldwide, ovarian aging has gradually become a key health problem among women. Over the years, various strategies have been developed to preserve fertility in women, while there are currently no clinical treatments to delay ovarian aging. Recently, advances in biomaterials and technologies, such as three-dimensional (3D) printing and microfluidics for the encapsulation of follicles and nanoparticles as delivery systems for drugs, have shown potential to be translational strategies for ovarian aging. This review introduces the research progress on the mechanisms underlying ovarian aging, and summarizes the current state of biomaterials in the evaluation and treatment of ovarian aging, including safety, potential applications, future directions and difficulties in translation. Graphical Abstract

Chemotherapy is often a cause of premature ovarian insufficiency and infertility since the ovarian follicles are extremely sensitive to the effects of chemotherapeutic agents. Different chemotherapeutic agents with varying mechanisms of action may damage ovarian function differently. Taxanes are widely used in clinical cancer treatment, but the specific reproductive toxicological information is still controversial. This review described the impact and duration of taxanes on ovarian function in women and analyzed the possible reasons for different conclusions. Furthermore, the toxicity of taxanes on ovarian function and its possible mechanisms were discussed. The potential protective strategies and agents against ovarian damage induced by taxanes are also reviewed.

Our understanding of how aging affects the cellular and molecular components of the human ovary and contributes to age-related fertility decline is still limited. Here, we link single-cell RNA sequencing and spatial transcriptomics to characterize human ovarian aging. Changes of the molecular signatures of eight types of ovarian cells during aging were defined. We combined single cell types with their spatial location information to divide ovarian granulosa cells into three subtypes and theca & stroma cells into five subtypes. Further analysis revealed increased cellular senescence with age and characterized the transcription factor FOXP1 as a master regulatory gene during ovarian aging. Inhibition of FOXP1 in ovarian cells increased cellular senescence which was alleviated by pharmacological treatment with quercetin or fisetin. These findings provide a comprehensive understanding of the spatiotemporal variability of human ovarian aging, providing resources for developing new diagnostic biomarkers and therapeutic strategies against ovarian aging.

Semaphorins are a family of evolutionarily conserved morphogenetic molecules that were initially found to be associated with axonal guidance. Semaphorin 4C (Sema4C), a member of the fourth subfamily of semaphorins, has been demonstrated to play multifaceted and important roles in organ development, immune regulation, tumour growth and metastasis. However, it is completely unknown whether Sema4C is involved in the regulation of ovarian function. We found that Sema4C was widely expressed in the stroma, follicles and corpus luteum of mouse ovaries, and its expression was decreased at distinct foci in ovaries of mice of mid-to-advanced reproductive age. Inhibition of Sema4C by the ovarian intrabursal administration of recombinant adeno-associated virus (AAV)-shRNA significantly reduced oestradiol, progesterone and testosterone levels in vivo. Transcriptome sequencing analysis showed changes in pathways related to ovarian steroidogenesis and the actin cytoskeleton. Similarly, knockdown of Sema4C by siRNA interference in mouse primary ovarian granulosa cells (GCs) or thecal interstitial cells (TICs) significantly suppressed ovarian steroidogenesis and led to actin cytoskeleton disorganization. Importantly, the cytoskeleton-related pathway RHOA/ROCK1 was simultaneously inhibited after downregulation of Sema4C. Furthermore, treatment with a ROCK1 agonist after siRNA interference stabilized the actin cytoskeleton and reversed the inhibitory effect on steroid hormones described above. In conclusion, Sema4C may play an important role in ovarian steroidogenesis through regulation of the actin cytoskeleton via the RHOA/ROCK1 signalling pathway. These findings shed new light on the identification of dominant factors involved in the endocrine physiology of female reproduction.

STUDY QUESTION Could inhibition of the checkpoint kinase (CHEK) pathway protect human oocytes and even enhance the anti-tumour effects, during chemotherapy? SUMMARY ANSWER CHEK inhibitors prevented apoptosis of human oocytes induced by chemotherapy and even enhanced the anti-tumour effects. WHAT IS KNOWN ALREADY CHEK inhibitors showed ovarian protective effects in mice during chemotherapy, while their role in human oocytes is unclear. STUDY DESIGN, SIZE, DURATION This experimental study evaluated the ovarian reserve of young patients (120 patients) with cancer, exposed or not exposed to taxane and platinum (TP)-combined chemotherapy. Single RNA-sequencing analysis of human primordial oocytes from 10 patients was performed to explore the mechanism of oocyte apoptosis induced by TP chemotherapy. The damaging effects of paclitaxel (PTX) and cisplatin on human oocytes were also evaluated by culturing human ovaries in vitro. A new mouse model that combines human ovarian xenotransplantation and patient-derived tumour xenografts was developed to explore adjuvant therapies for ovarian protection. The mice were randomly allocated to four groups (10 mice for each group): control, cisplatin, cisplatin + CK1 (CHEK1 inhibitor, SCH 900776), and cisplatin + CK2 (CHEK2 inhibitor, BML277). PARTICIPANTS/MATERIALS, SETTING, METHODS In the prospective cohort study, human ovarian follicles were counted and serum AMH levels were evaluated. RNA-sequencing analysis was conducted, and staining for follicular damage (phosphorylated H2AX histone; γH2AX), terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling (TUNEL) assays and assessments of apoptotic biomarkers (western blot and immunofluorescence) were conducted in human ovaries. After the treatments, histological analysis was performed on human ovarian samples to investigate follicular populations, and oocyte damage was measured by γH2AX staining, BAX staining, and TUNEL assays. At the same time, the tumours were evaluated for volume, weight, and apoptosis levels. MAIN RESULTS AND THE ROLE OF CHANCE Patients who received TP chemotherapy showed decreased ovarian reserves. Single RNA-sequencing analysis of human primordial oocytes indicated that TP chemotherapy induced apoptosis of human primordial oocytes by causing CHEK-mediated TAp63α phosphorylation. In vitro culture of human ovaries showed greater damaging effects on oocytes after cisplatin treatment compared with that after PTX treatment. Using the new animal model, CHEK1/2 inhibitors prevented the apoptosis of human oocytes induced by cisplatin and even enhanced its anti-tumour effects. This protective effect appeared to be mediated by inhibiting DNA damage via the CHEK-TAp63α pathway and by generation of anti-apoptotic signals in the oocytes. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION This was a preclinical study performed with human ovarian samples, and clinical research is required for validation. WIDER IMPLICATIONS OF THE FINDINGS These findings highlight the therapeutic potential of CHEK1/2 inhibitors as a complementary strategy for preserving fertility in female cancer patients. STUDY FUNDING/COMPETING INTEREST(S) This work was financially supported by the National Natural Science Foundation of China (nos. 82001514 and 81902669) and the Fundamental Research Funds for the Central Universities (2021yjsCXCY087). The authors declare no conflict of interest.

STUDY QUESTION Does cancer itself, before any gonadotoxic treatment, affect ovarian function in reproductive-aged patients? SUMMARY ANSWER Our study revealed that women with cancer may have decreased ovarian reserve markers even before cancer therapy. WHAT IS KNOWN ALREADY With the field “oncofertility” improving rapidly, cancer therapy-mediated ovarian damage is well characterised. However, there is a controversy about whether cancer itself affects ovarian function before gonadotoxic treatment. STUDY DESIGN, SIZE, DURATION We conducted a systematic meta-analysis investigating the association between cancer and ovarian function prior to gonadotoxic treatment. Titles or abstracts related to ovarian reserve [e.g., anti-Müllerian hormone (AMH), antral follicle count (AFC) or basal follicle-stimulating hormone (FSH)] combined with titles or abstracts related to the exposure (e.g., cancer*, oncolog* or malignan*) were searched in PubMed, Embase and Web of Science databases from inception to Feb 1, 2022. PARTICIPANTS/MATERIALS, SETTING, METHODS We included cohort, case-control and cross-sectional studies in English that examined ovarian reserve in reproductive-aged patients (18-45 years) with cancer compared to age-matched controls before cancer treatment. The quality of the included studies was assessed by ROBINS-I. Fixed or random effects were conducted to estimate standard or weighted mean difference (SMD or WMD, respectively) and confidence interval (CI). Heterogeneity was assessed by the Q test and I2 statistics, and publication bias was evaluated by Egger’s and Begg’s tests. MAIN RESULTS AND THE ROLE OF CHANCE The review identified 17 eligible studies for inclusion. The results showed that cancer patients had lower serum AMH levels compared to healthy controls (SMD = -0.19, 95% CI: -0.34 to -0.03, P = 0.001), especially women with hematological malignancies (SMD = -0.62, 95% CI: -0.99 to -0.24, P = 0.001). The AFC was also decreased in patients with cancer (WMD = -0.93, 95%CI: -1.79 to -0.07, P = 0.033) compared to controls, while inhibin B and basal FSH levels showed no statistically significant differences. LIMITATIONS, REASONS FOR CAUTION Serum AMH and basal FSH levels in this meta-analysis showed high heterogeneity, and the small number of studies contributing to most subgroup analyses limited the heterogeneity analysis. Moreover, the studies for specific cancer subtypes may be too small to draw conclusions; more studies are needed to investigate the possible impact of cancer type and stage on ovarian function. WIDER IMPLICATIONS OF THE FINDINGS Our study confirmed the findings that cancer per se, especially hematological malignancies, negatively affects serum AMH level and AFC values of reproductive-aged women. However, the lower AMH levels and AFCs may also be due to the changes in ovarian physiology under oncological conditions, rather than actual lower ovarian reserves. Based on the meta-analysis, clinicians should raise awareness about the possible need for personalized approaches for young women with cancer who are interested in pursuing fertility preservation strategies before anticancer treatments. STUDY FUNDING/COMPETING INTEREST(S) This work was financially supported by the National Natural Science Foundation of China (no. 81873824, no. 82001514 and no.81902669) and the Applied Basic Research Program of Wuhan Municipal Bureau of Science and Technology (2019020701011436). The authors declare that they have no conflict of interest. REGISTRATION NUMBER PROSPERO (CRD42021235954) WHAT DOES THIS MEAN FOR PATIENTS? Over the past decades, the incidence of cancer in young women has increased constantly. Cancer therapy-mediated damage to the ovary is well characterized, but whether cancer itself, prior to cytotoxic treatment, affects ovarian function is controversial. Ovarian reserve is generally defined as the quantity of oocytes remaining in the ovary, and markers of ovarian reserve include the hormone levels of anti-Müllerian hormone (AMH), inhibin B and basal follicle-stimulating hormone (FSH) and the sonographically measured antral follicle count (AFC). Among these, AMH and AFC are the most favourable indicators of ovarian reserve. Based on the results of this meta-analysis, patients with cancer had significant decreased serum AMH levels and AFC values before cancer treatment, while basal FSH levels and inhibin B levels showed no difference between cancer patients and control groups. From these results, we suggest that cancer itself may have negative effects on ovarian reserve. These findings may provide valuable information to clinicians and patients for choosing effective fertility preservation measures before cancer treatment.