Differentiation of Testis Xenografts in the Prepubertal Marmoset Depends on the Sex and Status of the Mouse Host

Downregulation of circLPAR3 inhibits tumor progression and glycolysis by liberating miR‐144‐3p and upregulating LPCAT1 in oral squamous cell carcinoma

Background

Increasing evidence demonstrated the important roles of circular RNAs (circRNAs) in human cancer progression, including oral squamous cell carcinoma (OSCC). The study intentions were to explore the role and molecular mechanism of hsa_circ_0004390 (circLPAR3) in OSCC progression.

Methods

Expression of circLPAR3 in collected samples and cultured cell lines was detected with real‐time quantitative reverse transcription‐polymerase chain reaction (RT‐qPCR). Loss‐of‐function experiments were performed to determine the effect of circLPAR3 silencing on OSCC cell proliferation, migration, invasion, apoptosis, angiopoiesis, and glycolysis. The sponge function of circLPAR3 was predicted by bioinformatics analysis and validated by the dual‐luciferase reporter and RNA pull‐down assays. In vivo experiments were conducted to validate the function of circLPAR3.

Results

A marked increase in circLPAR3 expression was observed in OSCC samples and cell lines. Furthermore, circLPAR3 could distinguish OSCC samples from paired non‐tumor samples, and patients with high circLPAR3 expression had a poor prognosis. Furthermore, circLPAR3 inhibition decreased OSCC growth in xenograft mouse models. Moreover, circLPAR3 silencing repressed cell proliferation, migration, invasion, angiopoiesis, glycolysis, and induced cell apoptosis in OSCC cells in vitro. Mechanically, circLPAR3 sponged miR‐144‐3p to prohibit the inhibiting effect of miR‐144‐3p on LPCAT1, thus promoting OSCC progression.

Conclusion

CircLPAR3 exerted a tumor‐promoting effect on OSCC growth through elevating LPCAT1 expression via functioning as a miR‐144‐3p sponge. This study supports the possible role of circLPAR3 in the diagnosis, prognosis, and treatment of OSCC.

Limited spermatogenic differentiation of testicular tissue from prepubertal marmosets (Callithrix jacchus) in an in vitro organ culture system

PURPOSE

of the research: To achieve male fertility preservation and restoration, experimental strategies for in vitro germ cell differentiation are required. The effects of two different culture conditions on in vitro maintenance and differentiation of non-human primate germ cells was studied. Three testes from three 6-month-old marmosets were cultured using a gas-liquid interphase system for 12 days. Testicular maturation in pre-culture control and samples cultured in gonadotropin and serum supplemented and non-supplemented culture samples was evaluated using Periodic Acid-Schiff (PAS) and immunohistochemical stainings.

PRINCIPLE RESULTS

Gonadotropins and serum-supplemented tissues demonstrate up to meiotic differentiation (BOULE + Pachytene spermatocyte) and advanced localization of germ cells (MAGEA4+). Moreover, complex (with gonadotropin and marmoset monkey serum) conditions induced progression in somatic cell maturation with advanced seminiferous epithelial organization, maintenance of encapsulation of cultured fragments with peritubular-myoid cells, preservation of tubular structural integrity and architecture.

MAJOR CONCLUSIONS

We report stimulation-dependent in vitro meiotic transition in non-human primate testes. This model represents a novel ex vivo approach to obtain crucial developmental progression.

Fertility preservation for prepubertal boys: lessons learned from the past and update on remaining challenges towards clinical translation

BACKGROUND

Childhood cancer incidence and survivorship are both on the rise. However, many lifesaving treatments threaten the prepubertal testis. Cryopreservation of immature testicular tissue (ITT), containing spermatogonial stem cells (SSCs), as a fertility preservation (FP) option for this population is increasingly proposed worldwide. Recent achievements notably the birth of non-human primate (NHP) progeny using sperm developed in frozen-thawed ITT autografts has given proof of principle of the reproductive potential of banked ITT. Outlining the current state of the art on FP for prepubertal boys is crucial as some of the boys who have cryopreserved ITT since the early 2000s are now in their reproductive age and are already seeking answers with regards to their fertility.

OBJECTIVE AND RATIONALE

In the light of past decade achievements and observations, this review aims to provide insight into relevant questions for clinicians involved in FP programmes. Have the indications for FP for prepubertal boys changed over time? What is key for patient counselling and ITT sampling based on the latest achievements in animals and research performed with human ITT? How far are we from clinical application of methods to restore reproductive capacity with cryostored ITT?

SEARCH METHODS

An extensive search for articles published in English or French since January 2010 to June 2020 using keywords relevant to the topic of FP for prepubertal boys was made in the MEDLINE database through PubMed. Original articles on fertility preservation with emphasis on those involving prepubertal testicular tissue, as well as comprehensive and systematic reviews were included. Papers with redundancy of information or with an absence of a relevant link for future clinical application were excluded. Papers on alternative sources of stem cells besides SSCs were excluded.

OUTCOMES

Preliminary follow-up data indicate that around 27% of boys who have undergone testicular sampling as an FP measure have proved azoospermic and must therefore solely rely on their cryostored ITT to ensure biologic parenthood. Auto-transplantation of ITT appears to be the first technique that could enter pilot clinical trials but should be restricted to tissue free of malignant cells. While in vitro spermatogenesis circumvents the risk linked to cancer cell contamination and has led to offspring in mice, complete spermatogenesis has not been achieved with human ITT. However, generation of haploid germ cells paves the way to further studies aimed at completing the final maturation of germ cells and increasing the efficiency of the processes.

WIDER IMPLICATIONS

Despite all the research done to date, FP for prepubertal boys remains a relatively young field and is often challenging to healthcare providers, patients and parents. As cryopreservation of ITT is now likely to expand further, it is important not only to acknowledge some of the research questions raised on the topic, e.g. the epigenetic and genetic integrity of gametes derived from strategies to restore fertility with banked ITT but also to provide healthcare professionals worldwide with updated knowledge to launch proper multicollaborative care pathways in the field and address clinical issues that will come-up when aiming for the child's best interest.

Long-Term Monitoring of Donor Xenogeneic Testis Tissue Grafts and Cell Implants in Recipient Mice Using Ultrasound Biomicroscopy

Testis tissue xenografting and testis cell aggregate implantation from various donor species into recipient mice are novel models for the study and manipulation of testis formation and function in target species. Thus far, the analysis of such studies has been limited to surgical or post-mortem retrieval of samples. Here we used ultrasound biomicroscopy (UBM) to monitor the development of neonatal porcine testis grafts and implants in host mice for 24 wk, and to correlate UBM and (immuno)histologic changes. This led to long-term visualization of gradual changes in volume, dimension and structure of grafts and implants; detection of a 4 wk developmental gap between grafts and implants; and revelation of differences in implant development depending on the craniocaudal site of implantation on the back of host mice. Our data support the reliability and precision of UBM for longitudinal study of transplants, which eliminates the need for frequent surgical sampling.

Fertility Preservation in Childhood Cancer: Endocrine Activity in Prepubertal Human Testis Xenografts Exposed to a Pubertal Hormone Environment

Simple Summary

Substantial strides have been made in treating childhood cancers; however, as a result of chemotherapy and radiotherapy, young males experience long-term side effects, including impaired fertility. Whilst prepubertal testicular tissue can be cryopreserved prior to gonadotoxic treatments, it remains to be determined how to generate mature gametes from the immature human testis tissue. Development of immature germ cells into sperm is a complex process, which is supported by mature Sertoli cells and testosterone produced from Leydig cells. We used an established testicular xenotransplantation model to investigate the effect of puberty hormones, known as gonadotrophins, on functional maturation of the spermatogonial stem cell (SSC) niche. Limited testosterone production and partial maturation of Sertoli cells occurred in prepubertal testis grafts, suggesting that longer periods of grafting and/or identification of additional factors are required to develop testicular transplantation as a model for fertility preservation in male survivors of childhood cancer.

Abstract

Survivors of childhood cancer are at risk for long-term treatment-induced health sequelae, including gonadotoxicity and iatrogenic infertility. At present, for prepubertal boys there are no viable clinical options to preserve future reproductive potential. We investigated the effect of a pubertal induction regimen with gonadotrophins on prepubertal human testis xenograft development. Human testis tissue was obtained from patients with cancer and non-malignant haematological disorders (n = 6; aged 1–14 years) who underwent testis tissue cryopreservation for fertility preservation. Fresh and frozen-thawed testis fragments were transplanted subcutaneously or intratesticularly into immunocompromised mice. Graft-bearing mice received injections of vehicle or exogenous gonadotrophins, human chorionic gonadotrophin (hCG, 20 IU), and follicle-stimulating hormone (FSH, 12.5 IU) three times a week for 12 weeks. The gross morphology of vehicle and gonadotrophin-exposed grafts was similar for both transplantation sites. Exposure of prepubertal human testis tissue xenografts to exogenous gonadotrophins resulted in limited endocrine function of grafts, as demonstrated by the occasional expression of the steroidogenic cholesterol side-chain cleavage enzyme (CYP11A1). Plasma testosterone concentrations (0.13 vs. 0.25 ng/mL; p = 0.594) and seminal vesicle weights (10.02 vs. 13.93 mg; p = 0.431) in gonadotrophin-exposed recipient mice were comparable to vehicle-exposed controls. Regardless of the transplantation site and treatment, initiation and maintenance of androgen receptor (AR) expression were observed in Sertoli cells, indicating commitment towards a more differentiated status. However, neither exogenous gonadotrophins (in castrated host mice) nor endogenous testosterone (in intact host mice) were sufficient to repress the expression of markers associated with immature Sertoli cells, such as anti-Müllerian hormone (AMH) and Ki67, or to induce the redistribution of junctional proteins (connexin 43, CX43; claudin 11, CLDN11) to areas adjacent to the basement membrane. Spermatogonia did not progress developmentally but remained the most advanced germ cell type in testis xenografts. Overall, these findings demonstrate that exogenous gonadotrophins promote partial activation and maturation of the somatic environment in prepubertal testis xenografts. However, alternative hormone regimens or additional factors for pubertal induction are required to complete the functional maturation of the spermatogonial stem cell (SSC) niche.