Intratubular germ cell neoplasia of the human testis: heterogeneous protein expression and relation to invasive potential

Disruption of gonocyte development following neonatal exposure to di (2-ethylhexyl) phthalate

Pre- and/or post-natal administrations of di(2-ethylhexyl) phthalate (DEHP) in experimental animals cause alterations in the spermatogenesis. However, the mechanism by which DEHP affects fertility is unknown and could be through alterations in the survival and differentiation of the gonocytes. The aim of the present study was to evaluate the effect of a single administration of DEHP in newborn mice on gonocytic proliferation, differentiation and survival and its long-term effects on seminiferous epithelium and sperm quality. BALB/c mice distributed into Control and DEHP groups were used. Each animal in the DEHP group was given a single dose of 500 mg/Kg at birth. The animals were analyzed at 1, 2, 4, 6, 8, 10 and 70 days postpartum (dpp). Testicular tissues were processed for morphological analysis to determine the different types of gonocytes, differentiation index, seminiferous epithelial alterations, and immunoreactivity to Stra8, Pcna and Vimentin proteins. Long-term evaluation of the seminiferous epithelium and sperm quality were carried out at 70 dpp. The DEHP animal group presented gonocytic degeneration with delayed differentiation, causing a reduction in the population of spermatogonia (Stra8 +) in the cellular proliferation (Pcna+) and disorganization of Vimentin filaments. These events had long-term repercussions on the quality of the seminiferous epithelium and semen. Our study demonstrates that at birth, there is a period that the testes are extremely sensitive to DEHP exposure, which leads to gonocytic degeneration and delay in their differentiation. This situation can have long-term repercussions or permanent effects on the quality of the seminiferous epithelium and sperm parameters.

HCR spectral imaging: 10-plex, quantitative, high-resolution RNA and protein imaging in highly autofluorescent samples

Signal amplification based on the mechanism of hybridization chain reaction (HCR) provides a unified framework for multiplex, quantitative, high-resolution imaging of RNA and protein targets in highly autofluorescent samples. With conventional bandpass imaging, multiplexing is typically limited to four or five targets owing to the difficulty in separating signals generated by fluorophores with overlapping spectra. Spectral imaging has offered the conceptual promise of higher levels of multiplexing, but it has been challenging to realize this potential in highly autofluorescent samples, including whole-mount vertebrate embryos. Here, we demonstrate robust HCR spectral imaging with linear unmixing, enabling simultaneous imaging of ten RNA and/or protein targets in whole-mount zebrafish embryos and mouse brain sections. Further, we demonstrate that the amplified and unmixed signal in each of the ten channels is quantitative, enabling accurate and precise relative quantitation of RNA and/or protein targets with subcellular resolution, and RNA absolute quantitation with single-molecule resolution, in the anatomical context of highly autofluorescent samples.

Dissociation, enrichment, and the in vitro formation of gonocyte colonies from cryopreserved neonatal bovine testicular tissues

Gonocytes play an important role in early development of spermatogonial stem cells and fertility preservation to acquire more high quality gonocytes in vitro for further germ cell-related research and applications, it is necessarily needed to enrich and in vitro propagate gonocytes from cryopreserved bovine testicular tissues. This study aimed to investigate the isolation, enrichment, and colony formation of gonocytes in vitro for germ cell expansion from cryopreserved neonatal bovine testicular tissues. The effects of several different in vitro culture conditions, including seeding density, temperature, serum replacement and extracellular matrices were investigated for the maintenance, proliferation and formation of gonocyte colonies in vitro. Frozen/thawed two-week-old neonatal bovine testicular tissues were digested and gonocytes were enriched using a Percoll density gradient. Cell viability was accessed by trypan blue staining and cell apoptosis was evaluated by TUNEL assays. Gonocytes were identified and confirmed by immunofluorescence with the PGP9.5 germ cell marker and the OCT4 pluripotency marker while Sertoli cells were stained with vimentin. We found that neonatal bovine gonocytes were efficiently enriched by a 30%-40% Percoll density gradient (p < 0.05). No significant differences were detected between neonatal bovine testicular cells cultured at 34 °C or 37 °C. The formation of gonocyte colonies was observed in culture medium supplemented with knockout serum replacement (KSR), but not fetal bovine serum (FBS), at a seeding density higher than 5.0 × 104 cells/well. A greater number of gonocyte colonies were observed in culture plates coated with laminin (38.00 ± 6.24/well) and Matrigel (38.67 ± 3.78/well) when compared to plates coated with collagen IV and fibronectin (p < 0.05). In conclusion, bovine neonatal gonocytes were able to be efficiently isolated, enriched and maintained in gonocyte colonies in vitro; the development of this protocol provides vital information for the clinical translation of this technology and the future restoration of human fertility.

HCR spectral imaging: 10-plex, quantitative, high-resolution RNA and protein imaging in highly autofluorescent samples

Signal amplification based on the mechanism of hybridization chain reaction (HCR) provides a unified framework for multiplex, quantitative, high-resolution imaging of RNA and protein targets in highly autofluorescent samples. With conventional bandpass imaging, multiplexing is typically limited to four or five targets due to the difficulty in separating signals generated by fluorophores with overlapping spectra. Spectral imaging has offered the conceptual promise of higher levels of multiplexing, but it has been challenging to realize this potential in highly autofluorescent samples including whole-mount vertebrate embryos. Here, we demonstrate robust HCR spectral imaging with linear unmixing, enabling simultaneous imaging of 10 RNA and/or protein targets in whole-mount zebrafish embryos and mouse brain sections. Further, we demonstrate that the amplified and unmixed signal in each of 10 channels is quantitative, enabling accurate and precise relative quantitation of RNA and/or protein targets with subcellular resolution, and RNA absolute quantitation with single-molecule resolution, in the anatomical context of highly autofluorescent samples.

SUMMARY

Spectral imaging with signal amplification based on the mechanism of hybridization chain reaction enables robust 10-plex, quantitative, high-resolution imaging of RNA and protein targets in whole-mount vertebrate embryos and brain sections.

Precocious Puberty in a Boy With Bilateral Leydig Cell Tumors due to a Somatic Gain-of-Function LHCGR Variant

Context

Autosomal dominant and rarely de novo gain-of-function variants in the LHCGR gene are associated with precocious male puberty, while somatic LHCGR variants have been found in isolated Leydig cell adenomas and Leydig cell hyperplasia. Bilateral diffuse Leydig cell tumor formation in peripheral precocious male puberty has not been reported.

Case Description

We present a boy with gonadotropin-independent precocious puberty and rapid virilization beginning in infancy resistant to standard therapy. Treatment with abiraterone in addition to letrozole and bicalutamide proved effective. Bilateral diffuse Leydig cell tumors were identified at age 5 years.

Results

Whole-genome sequencing of tumor and blood samples was performed. The patient was confirmed to have bilateral, diffuse Leydig cell tumors harboring the somatic, gain-of-function p.Asp578His variant in the LHCGR gene. Digital droplet polymerase chain reaction of the LHCGR variant performed in tumor and blood samples detected low levels of this same variant in the blood.

Conclusion

We report a young boy with severe gonadotropin-independent precocious puberty beginning in infancy who developed bilateral diffuse Leydig cell tumors at age 5 years due to a somatic gain-of-function p.Asp578His variant in LHCGR. The gain-of-function nature of the LHCGR variant and the developmental timing of the somatic mutation likely play a role in the risk of tumor formation. Abiraterone (a CYP17A1 inhibitor), in combination with an antiandrogen, aromatase inhibitor, and glucocorticoid, appears to be an effective therapy for severe peripheral precocious puberty in boys.

Testicular Germ Cell Tumours and Proprotein Convertases

Simple Summary

Despite the high survival rate of the most common neoplasia in young Caucasian men: Testicular Germ Cell Tumors (TGCT), the quality of life of these patients is impaired by the multiple long-term side effects of their treatment. The study of molecules that can serve both as diagnostic biomarkers for tumor development and as therapeutic targets seems necessary. Proprotein convertases (PC) are a group of proteases responsible for the maturation of inactive proproteins with very diverse functions, whose alterations in expression have been associated with various diseases, such as other types of cancer and inflammation. The study of the immune tumor microenvironment and the substrates of PCs could contribute to the development of new and necessary immunotherapies to treat this pathology.

Abstract

Testicular Germ Cell Tumours (TGCT) are widely considered a “curable cancer” due to their exceptionally high survival rate, even if it is reduced by many years after the diagnosis due to metastases and relapses. The most common therapeutic approach to TGCTs has not changed in the last 50 years despite its multiple long-term side effects, and because it is the most common malignancy in young Caucasian men, much research is needed to better the quality of life of the many survivors. Proprotein Convertases (PC) are nine serine proteases responsible for the maturation of inactive proproteins with many diverse functions. Alterations in their expression have been associated with various diseases, including cancer and inflammation. Many of their substrates are adhesion molecules, metalloproteases and proinflammatory molecules, all of which are involved in tumour development. Inhibition of certain convertases has also been shown to slow tumour formation, demonstrating their involvement in this process. Considering the very established link between PCs and inflammation-related malignancies and the recent studies carried out into the immune microenvironment of TGCTs, the study of the involvement of PCs in testicular cancer may open up avenues for being both a biomarker for diagnosis and a therapeutic target.

Hybridization chain reaction enables a unified approach to multiplexed, quantitative, high-resolution immunohistochemistry and in situ hybridization

RNA in situ hybridization based on the mechanism of the hybridization chain reaction (HCR) enables multiplexed, quantitative, high-resolution RNA imaging in highly autofluorescent samples, including whole-mount vertebrate embryos, thick brain slices and formalin-fixed paraffin-embedded tissue sections. Here, we extend the benefits of one-step, multiplexed, quantitative, isothermal, enzyme-free HCR signal amplification to immunohistochemistry, enabling accurate and precise protein relative quantitation with subcellular resolution in an anatomical context. Moreover, we provide a unified framework for simultaneous quantitative protein and RNA imaging with one-step HCR signal amplification performed for all target proteins and RNAs simultaneously.

Altered Biology of Testicular VSELs and SSCs by Neonatal Endocrine Disruption Results in Defective Spermatogenesis, Reduced Fertility and Tumor Initiation in Adult Mice

Reproductive health of men has declined in recent past with reduced sperm count and increased incidence of infertility and testicular cancers mainly attributed to endocrine disruption in early life. Present study aims to evaluate whether testicular stem cells including very small embryonic-like stem cells (VSELs) and spermatogonial stem cells (SSCs) get affected by endocrine disruption and result in pathologies in adult life. Effect of treatment on mice pups with estradiol (20 μg on days 5-7) and diethylstilbestrol (DES, 2 μg on days 1-5) was studied on VSELs, SSCs and spermatogonial cells in adult life. Treatment affected spermatogenesis, tubules in Stage VIII & sperm count were reduced along with reduction of meiotic (4n) cells and markers (Prohibitin, Scp3, Protamine). Enumeration of VSELs by flow cytometry (2-6 μm, 7AAD-, LIN-CD45-SCA-1+) and qRT-PCR using specific transcripts for VSELs (Oct-4a, Sox-2, Nanog, Stella, Fragilis), SSCs (tOct-4, Gfra-1, Gpr-125) and early germ cells (Mvh, Dazl) showed several-fold increase but transition from c-Kit negative to c-Kit positive spermatogonial cells was blocked on D100 after treatment. Transcripts specific for apoptosis (Bcl2, Bax) remained unaffected but tumor suppressor (p53) and epigenetic regulator (NP95) transcripts showed marked disruption. 9 of 10 mice exposed to DES showed tumor-like changes. To conclude, endocrine disruption resulted in a tilt towards excessive self-renewal of VSELs (leading to testicular cancer after DES treatment) and blocked differentiation (reduced numbers of c-Kit positive cells, meiosis, sperm count and fertility). Understanding the underlying basis for infertility and cancer initiation from endogenous stem cells through murine modelling will hopefully improve human therapies in future.

Molecular Characterization of Testicular Germ Cell Tumors Using Tissue Microdissection

Testicular germ cell tumors are among the most common malignancies seen in children and young adults. Genomic studies have identified characteristic molecular profiles in testicular cancer, which are associated with histologic subtypes and may predict clinical behavior including treatment responses. Emerging molecular technologies analyzing tumor genomics, transcriptomics, and proteomics may now guide precision management of testicular tumors. Laser-assisted microdissection methods such as laser capture microdissection efficiently isolate selected tumor cells from routine pathology specimens, avoiding contamination from nontarget cell populations. Laser capture microdissection in combination with next generation sequencing makes precise high throughput genetic evaluation effective and efficient. The use of laser capture microdissection (LCM) for molecular testing may translate into great benefits for the clinical management of patients with testicular cancers. This review discusses application protocols for laser-assisted microdissection to investigate testicular germ cell tumors.

Testicular Stem Cell Dysfunction Due to Environmental Insults Could Be Responsible for Deteriorating Reproductive Health of Men

Reproductive health of men has declined over time including reduced semen quality specifically sperm count, increased incidence of infertility, and testicular cancers. Our recent findings suggest that these disease states possibly arise as a result of disruption of testicular stem cells biology by perinatal insults including exposure to endocrine disrupting chemicals. Testicular stem cells include relatively quiescent, very small embryonic-like stem cells (VSELs), and actively dividing spermatogonial stem cells (SSCs). Both VSELs and SSCs express estrogen receptors and are directly vulnerable to endocrine disruption. Exposing mice pups to estradiol (20 μg/pup/day on days 5-7) or diethylstilbestrol (2 μg/pup/day on days 1-5) affected spermatogenesis during adult life with reduced numbers of tubules in stage VIII, tetraploid cells and sperm. These mice were infertile and majority of diethylstilbestrol treated mice revealed testicular cancer-like changes. An increase in VSEL numbers, observed by both flow cytometry and qRT-PCR, was associated with marked reduction of c-KIT positive spermatogonial cells. VSELs undergo epigenetic changes due to endocrine disruption that results in blocked differentiation (impaired spermatogenesis) leading to reduced sperm count and infertility, and their excessive self-renewal initiates cancer-like changes in adult life. Thus, testicular dysgenesis syndrome (TDS) has a stem cell rather than a genetic basis.

Sequential Colocalization of ERa, PR, and AR Hormone Receptors Using Confocal Microscopy Enables New Insights into Normal Breast and Prostate Tissue and Cancers

Simple Summary

At present, platforms for multiplex immunohistochemistry (e.g., Opal) identify markers in distinct cell populations within a tissue section using multispectral fluorescence and optic microscopy. However, the optic resolution is not enough to colocalize markers at the subcellular level in the main epithelial or cancer population. We use confocal microscopy in multiplex detection of nuclear hormone receptors since they are an important part of the diagnosis and treatment of breast and prostate cancer. Moreover, we increased the quantitative dynamic range and resolution through increasing the signal/noise ration through reducing autofluorescence and increased longer antibody incubations. ColNu mIHCF identified distinct patterns of nuclear receptor colocalization in breast cancers. Furthermore, in prostate cancer all cancer epithelium was positive for ERa at the plasma membrane; and in normal prostate a small ERa+/p63+/AR− basal population suggest stem cell commitment to differentiation. ColNu mIHCF could be used for improving diagnosis and treatment in cancer.

Abstract

Multiplex immunohistochemistry (mIHC) use markers staining different cell populations applying widefield optical microscopy. Resolution is low not resolving subcellular co-localization. We sought to colocalize markers at subcellular level with antibodies validated for clinical diagnosis, including the single secondary antibody (combination of anti-rabbit/mouse-antibodies) used for diagnostic IHC with any primary antibody, and confocal microscopy. We explore colocalization in the nucleus (ColNu) of nuclear hormone receptors (ERa, PR, and AR) along with the baseline marker p63 in paired samples of breast and prostate tissues. We established ColNu mIHCF as a reliable technique easily implemented in a hospital setting. In ERa+ breast cancer, we identified different colocalization patterns (nuclear or cytoplasmatic) with PR and AR on the luminal epithelium. A triple-negative breast-cancer case expressed membrane-only ERa. A PR-only case was double positive PR/p63. In normal prostate, we identified an ERa+/p63+/AR-negative distinct population. All prostate cancer cases characteristically expressed ERa on the apical membrane of the AR+ epithelium. We confirmed this using ERa IHC and needle-core biopsies. ColNu mIHCF is feasible and already revealed a new marker for prostate cancer and identified sub-patterns in breast cancer. It could be useful for pathology as well as for functional studies in normal prostate and breast tissues.

A Novel Tissue and Stem Cell Specific TERF1 Splice Variant Is Downregulated in Tumour Cells

In this study, we describe the identification of a novel splice variant of TERF1/PIN2, one of the main components of the telomeric shelterin complex. This new splice variant is identical to TERF1, apart from a 30 amino acid internal insertion near to the C-terminus of TERF1. Based on genome comparison analyses and RNA expression data, we show that this splice variant is conserved among hominidae but absent from all other species. RNA expression and histological analyses show specific expression in human spermatogonial and hematopoietic stem cells (HSCs), while all other analyzed tissues lack the expression of this TERF1-isoform, hence the name TERF1-tsi (TERF1-tissue-specific-isoform). In addition, we could not detect any expression in primary human cells and established cancer cell lines. Immunohistochemistry results involving two new rabbit polyclonal antibodies, generated against TERF1-tsi specific peptides, indicate nuclear localization of TERF1-tsi in a subset of spermatogonial stem cells. In line with this observation, immunofluorescence analyzes in various cell lines consistently revealed that ectopic TERF1-tsi localizes to the cell nucleus, mainly but not exclusively at telomeres. In a first attempt to evaluate the impact of TERF1-tsi in the testis, we have tested its expression in normal testis samples versus matched tumor samples from the same patients. Both RT-PCR and IHC show a specific downregulation of TERF1-tsi in tumor samples while the expression of TERF1 and PIN2 remains unchanged.

The oncogene Gankyrin is expressed in testicular cancer and contributes to cisplatin sensitivity in embryonal carcinoma cells

BACKGROUND

Testicular germ cell cancer (TGCC) develops from pre-malignant germ neoplasia in situ (GCNIS) cells. GCNIS originates from fetal gonocytes (POU5F1+/MAGE-A4-), which fail to differentiate to pre-spermatogonia (POU5F1-/MAGE-A4+) and undergo malignant transformation. Gankyrin is an oncogene which has been shown to prevent POU5F1 degradation and specifically interact with MAGE-A4 in hepatocellular carcinoma (HCC) cells. We aimed to investigate the role of Gankyrin in progression from gonocyte to pre-invasive GCNIS and subsequent invasive TGCC.

METHODS

We determined Gankyrin expression in human fetal testicular tissue (gestational weeks 9-20; n = 38), human adult testicular tissue with active spermatogenesis (n = 9), human testicular tissue with germ cell maturation delay (n = 4), testicular tissue from patients with pre-invasive GCNIS (n = 6), and invasive TGCC including seminoma (n = 6) and teratoma (n = 7). Functional analysis was performed in-vitro by siRNA knock-down of Gankyrin in the NTera2 cells (derived from embryonal carcinoma).

RESULTS

Germ cell expression of Gankyrin was restricted to a sub-population of prespermatogonia in human fetal testes. Nuclear Gankyrin was also expressed in GCNIS cells of childhood and adult pre-invasive TGCC patients, and in GCNIS from seminoma and non-seminoma patients. Cytoplasmic expression was observed in seminoma tumour cells and NTera2 cells. Gankyrin knock-down in NTera2 cells resulted in an increase in apoptosis mediated via the TP53 pathway, whilst POU5F1 expression was unaffected. Furthermore, Gankyrin knock-down in NTera2 cells increased cisplatin sensitivity with an increase in cell death (13%, p < 0.05) following Gankyrin knock-down, when compared to cisplatin treatment alone, likely via BAX and FAS. Our results demonstrate that Gankyrin expression changes in germ cells during normal transition from gonocyte to prespermatogonia. In addition, changes in Gankyrin localisation are associated with progression of pre-invasive GCNIS to invasive TGCC. Furthermore, we found that Gankyrin is involved in the regulation of NTera2 cell survival and that a reduction in Gankyrin expression can modulate cisplatin sensitivity.

CONCLUSIONS

These results suggest that manipulation of Gankyrin expression may reduce the cisplatin dose required for the treatment of TGCC, with benefits in reducing dose-dependent side effects of chemotherapy. Further studies are required in order to assess the effects of modulating Gankyrin on GCNIS/TGCC using in vivo models.

B-cell lymphoma 2 ovarian killer suppresses testicular cancer cell malignant behavior, but plays a role in platinum resistance

Testicular cancer (TC) is the most common malignancy in men. Although the 5-year survival rate of TC patients exceeds 95%, the prognosis of patients with platinum-resistant tumors remains poor because of limited therapeutic options. Overcoming chemoresistance is the key to improving survival in poor-prognosis patients. However, the mechanism remains poorly understood. B-cell lymphoma 2 ovarian killer (BOK) is a proapoptotic protein and functions as a tumor suppressor in malignancy tumors. In this study, we found that BOK was frequently downregulated in TC tissues compared with paratumor tissues. BOK overexpression inhibited TC cell proliferation and invasion. In contrast, BOK knockdown promoted TC cell proliferation and invasion. Surprisingly, either BOK overexpression or knockdown rendered TC cells resistant to Cisplatin (DDP). In conclusion, BOK downregulation may be associated with tumorigenesis of TC. BOK had the potency to suppress TC cell proliferation and invasion, and may function as a tumor suppressor in TC. However, BOK also contributes to Cisplatin resistance. These data may provide a wider perspective on TC research and treatment.

Mechanisms of cisplatin sensitivity and resistance in testicular germ cell tumors

Testicular germ cell tumors (TGCTs) are a cancer pharmacology success story with a majority of patients cured even in the highly advanced and metastatic setting. Successful treatment of TGCTs is primarily due to the exquisite responsiveness of this solid tumor to cisplatin-based therapy. However, a significant percentage of patients are, or become, refractory to cisplatin and die from progressive disease. Mechanisms for both clinical hypersensitivity and resistance have largely remained a mystery despite the promise of applying lessons to the majority of solid tumors that are not curable in the metastatic setting. Recently, this promise has been heightened by the realization that distinct (and perhaps pharmacologically replicable) epigenetic states, rather than fixed genetic alterations, may play dominant roles in not only TGCT etiology and progression but also their curability with conventional chemotherapies. In this review, it discusses potential mechanisms of TGCT cisplatin sensitivity and resistance to conventional chemotherapeutics.

Testicular germ cell tumor: a comprehensive review

Testicular tumors are the most common tumors in adolescent and young men and germ cell tumors (TGCTs) account for most of all testicular cancers. Increasing incidence of TGCTs among males provides strong motivation to understand its biological and genetic basis. Gains of chromosome arm 12p and aneuploidy are nearly universal in TGCTs, but TGCTs have low point mutation rate. It is thought that TGCTs develop from premalignant intratubular germ cell neoplasia that is believed to arise from the failure of normal maturation of gonocytes during fetal or postnatal development. Progression toward invasive TGCTs (seminoma and nonseminoma) then occurs after puberty. Both inherited genetic factors and environmental risk factors emerge as important contributors to TGCT susceptibility. Genome-wide association studies have so far identified more than 30 risk loci for TGCTs, suggesting that a polygenic model fits better with the genetic landscape of the disease. Despite high cure rates because of its particular sensitivity to platinum-based chemotherapy, exploration of mechanisms underlying the occurrence, progression, metastasis, recurrence, chemotherapeutic resistance, early diagnosis and optional clinical therapeutics without long-term side effects are urgently needed to reduce the cancer burden in this underserved age group. Herein, we present an up-to-date review on clinical challenges, origin and progression, risk factors, TGCT mouse models, serum diagnostic markers, resistance mechanisms, miRNA regulation, and database resources of TGCTs. We appeal that more attention should be paid to the basic research and clinical diagnosis and treatment of TGCTs.

Immunolocalization of DMRTB1 in human testis with normal and impaired spermatogenesis

BACKGROUND

The transcription factor DMRTB1 plays a pivotal role in coordinating the transition between mitosis and meiosis in murine germ cells. No reliable data are available for human testis.

OBJECTIVES

The present study aims to examine the testicular expression pattern of DMRTB1 in men showing normal and impaired spermatogenesis.

MATERIALS AND METHODS

Immunohistochemistry was performed using 54 human testicular biopsy specimens and a commercial rabbit polyclonal anti-DMRTB1 primary antibody. RT-PCR complemented immunohistochemistry. To further characterize immunopositive cells and possible co-localization, the proliferation marker Ki-67, the tumor marker PLAP, and an anti-DMRT1 antibody were used.

RESULTS

In men with normal spermatogenesis, a strong immunoreactivity was detectable in a subset of spermatogonia (38.34 ± 2.14%). Some spermatocytes showed a weak immunostaining. Adjacent Sertoli cells were immunonegative. Compared with a hematoxylin and eosin overview staining, these immunopositive cells were almost exclusively identified as A_pale and B spermatogonia and primary spermatocytes in (pre-)leptotene, zygotene, and pachytene stages. In patients with spermatogenic arrest at spermatogonial level, an altered staining pattern was found. No immunoreactivity was detected in Sertoli cells in Sertoli cell-only syndrome. In germ cell neoplasia in situ (GCNIS) tubules, except for a few (0.4 ± 0.03%), pre-invasive tumor cells were immunonegative. Seminoma cells showed no immunostaining.

DISCUSSION

According to previous findings in mice, it seems reasonable that DMRTB1 is expressed in these normal germ cell populations. Moreover, altered staining pattern in spermatogenic arrest at spermatogonial stage suggests a correlation with mitosis and transformation into B spermatogonia. The absence of DMRTB1 in GCNIS cells and tumor cells might be associated with uncontrolled neoplastic cell proliferation and progression into invasive germ cell tumors. Further research is required to elucidate, for example, the role of DMRTB1 in the malignant transformation of human germ cells.

CONCLUSION

Our data indicate a relevant role for DMRTB1 regarding the entry of spermatogonia into meiosis in men.

Effects of Exposure to Acetaminophen and Ibuprofen on Fetal Germ Cell Development in Both Sexes in Rodent and Human Using Multiple Experimental Systems

BACKGROUND

Analgesic exposure during pregnancy may affect aspects of fetal gonadal development that are targeted by endocrine disruptors.

OBJECTIVES

We investigated whether therapeutically relevant doses of acetaminophen and ibuprofen affect germ cell (GC) development in human fetal testes/ovaries using in vitro and xenograft approaches.

METHODS

First-trimester human fetal testes/ovaries were cultured and exposed to acetaminophen or ibuprofen (7 d). Second-trimester human fetal testes were xenografted into mice and exposed to acetaminophen (1 or 7 d), or ibuprofen (7 d). To determine mechanism of action, a human GC tumor–derived cell line (NTera2) exhibiting fetal GC characteristics was used in addition to in vitro and in vivo rat models.

RESULTS AND DISCUSSION

Gonocyte (TFAP2C⁺) number was reduced relative to controls in first-trimester human fetal testes exposed in vitro to acetaminophen (-28%) or ibuprofen (-22%) and also in ovaries exposed to acetaminophen (-43%) or ibuprofen (-49%). Acetaminophen exposure reduced gonocyte number by 17% and 30% in xenografted second-trimester human fetal testes after treatment of host mice for 1 or 7 d, respectively. NTera2 cell number was reduced following exposure to either analgesic or prostaglandin E₂ (PGE₂) receptor antagonists, whereas PGE₂ agonists prevented acetaminophen-induced reduction in NTera2 cell number. Expression of GC pluripotency genes, and genes that regulate DNA/histone methylation, also differed from controls following analgesic and PGE₂ receptor antagonist exposures. Gene expression changes were observed in rat fetal testis/ovary cultures and after in vivo acetaminophen exposure of pregnant rats. For example, expression of the epigenetic regulator TET1, was increased following exposure to acetaminophen in human NTera2 cells, rat fetal testis/ovary cultures, and in fetal testes and ovaries after in vivo exposure of pregnant rats, indicating translatability across experimental models and species.

CONCLUSIONS

Our results demonstrate evidence of PGE₂-mediated effects of acetaminophen and ibuprofen on GC/NTera2 cells, which raises concerns about analgesic use during human pregnancy that warrant further investigation. https://doi.org/10.1289/EHP2307.

Quantitative Analysis of Immune Infiltrates in Primary Melanoma

Novel methods to analyze the tumor microenvironment (TME) are urgently needed to stratify melanoma patients for adjuvant immunotherapy. Tumor-infiltrating lymphocyte (TIL) analysis, by conventional pathologic methods, is predictive but is insufficiently precise for clinical application. Quantitative multiplex immunofluorescence (qmIF) allows for evaluation of the TME using multiparameter phenotyping, tissue segmentation, and quantitative spatial analysis (qSA). Given that CD3⁺CD8⁺ cytotoxic lymphocytes (CTLs) promote antitumor immunity, whereas CD68⁺ macrophages impair immunity, we hypothesized that quantification and spatial analysis of macrophages and CTLs would correlate with clinical outcome. We applied qmIF to 104 primary stage II to III melanoma tumors and found that CTLs were closer in proximity to activated (CD68⁺HLA-DR⁺) macrophages than nonactivated (CD68⁺HLA-DR^-) macrophages (P < 0.0001). CTLs were further in proximity from proliferating SOX10⁺ melanoma cells than nonproliferating ones (P < 0.0001). In 64 patients with known cause of death, we found that high CTL and low macrophage density in the stroma (P = 0.0038 and P = 0.0006, respectively) correlated with disease-specific survival (DSS), but the correlation was less significant for CTL and macrophage density in the tumor (P = 0.0147 and P = 0.0426, respectively). DSS correlation was strongest for stromal HLA-DR⁺ CTLs (P = 0.0005). CTL distance to HLA-DR^- macrophages associated with poor DSS (P = 0.0016), whereas distance to Ki67^- tumor cells associated inversely with DSS (P = 0.0006). A low CTL/macrophage ratio in the stroma conferred a hazard ratio (HR) of 3.719 for death from melanoma and correlated with shortened overall survival (OS) in the complete 104 patient cohort by Cox analysis (P = 0.009) and merits further development as a biomarker for clinical application. Cancer Immunol Res; 6(4); 481-93. ©2018 AACR.

Testicular cancer from diagnosis to epigenetic factors

Testicular cancer (TC) is one of the most common neoplasms that occurs in male and includes germ cell tumors (GCT), sex cord-gonadal stromal tumors and secondary testicular tumors. Diagnosis of TC involves the evaluation of serum tumor markers alpha-fetoprotein, human chorionic gonadotropin and lactate dehydrogenase, but clinically several types of immunohistochemical markers are more useful and more sensitive in GCT, but not in teratoma. These new biomarkers are genes expressed in primordial germ cells/gonocytes and embryonic pluripotency-related cells but not in normal adult germ cells and they include PLAP, OCT3/4 (POU5F1), NANOG, SOX2, REX1, AP-2γ (TFAP2C) and LIN28. Gene expression in GCT is regulated, at least in part, by DNA and histone modifications, and the epigenetic profile of these tumours is characterised by genome-wide demethylation. There are different epigenetic modifications in TG-subtypes that reflect the normal developmental switch in primordial germ cells from an under- to normally methylated genome. The main purpose of this review is to illustrate the findings of recent investigations in the classification of male genital organs, the discoveries in the use of prognostic and diagnostic markers and the epigenetic aberrations mainly affecting the patterns of DNA methylation/histone modifications of genes (especially tumor suppressors) and microRNAs (miRNAs).

Transplacental exposure to environmental carcinogens: Association with childhood cancer risks and the role of modulating factors

Biological responses to carcinogens from environmental exposure during adulthood are modulated over years or decades. Conversely, during transplacental exposure, the effects on the human foetus change within weeks, intertwining with developmental mechanisms: even short periods of transplacental exposure may be imprinted in the organism for a lifetime. The pathways leading to childhood and juvenile cancers, such as leukaemias, neuroblastoma/brain tumours, hepatoblastoma, and Willm's tumour involve prenatally-induced genomic, epigenomic and/or non-genomic effects caused by xenobiotics. Pregnant women most often live in complex environmental settings that cause transplacental exposure of the foetus to xenobiotic mixtures. Mother-child biomonitoring should integrate the analysis of chemicals/radiation present in the living and workplace environment with relevant risk modulators related to life style. The interdisciplinary approach for transplacental cancer risk assessment in high-pressure areas should be based on an integrated model for mother-child exposure estimation via profiling the exposure level by water quality analysis, usage of emission grids, and land use maps.

Analgesic use in pregnancy and male reproductive development

PURPOSE OF REVIEW

Male reproductive disorders are common and increasing in incidence in many countries. Environmental factors (including pharmaceuticals) have been implicated in the development of these disorders. This review aims to summarize the emerging epidemiological and experimental evidence for a potential role of in-utero exposure to analgesics in the development of male reproductive disorders.

RECENT FINDINGS

A number of epidemiological studies have demonstrated an association between in utero exposure to analgesics and the development of cryptorchidism, although these findings are not consistent across all studies. Where present, these associations primarily relate to exposure during the second trimester of pregnancy. In vivo and in vitro experimental studies have demonstrated variable effects of exposure to analgesics on Leydig cell function in the fetal testis of rodents, particularly in terms of testosterone production. These effects frequently involve exposures that are in excess of those to which humans are exposed. Investigation of the effects of analgesics on human fetal testis have also demonstrated effects on Leydig cell function. Variation in species, model system, dosage and timing of exposure is likely to contribute to differences in the findings between studies.

SUMMARY

There is increasing evidence for analgesic effects on the developing testis that have the potential to impair male reproductive function. However, the importance of these findings in relation to human-relevant exposures and the risk of male reproductive disorders remain unclear.

Fibrillin-1 (FBN-1) a new marker of germ cell neoplasia in situ

Background

Germ cell neoplasia in situ (GCNIS), is preinvasive stage of testicular germ cell tumours (TGCTs). Fibrillins, which are integral components of microfibrils are suggested to be involved in cancer pathogenesis and maintenance of embryonic stem cells pluripotency. The aim of this study was to examine fibrillin-1 (FBN-1) expression in TGCTs patients.

Methods

Surgical specimens from 203 patients with TGCTs were included into the translational study. FBN-1 expression was evaluated in the tumour tissue, in GCNIS and in adjacent non-neoplastic testicular tissue in all available cases. Tissue samples were processed by the tissue microarray method. FBN-1 was detected by immunohistochemistry using goat polyclonal antibody and the expression was evaluated by the multiplicative quickscore (QS).

Results

The highest FBN-1 positivity was detected in GCNIS (mean QS = 11.30), with overexpression of FBN-1 (QS >9) in the majority (77.1 %) of cases. Expression of FBN-1 in all subtypes of TGCTs was significantly lower in comparison to expression in GCNIS (all p <0.001). Seminoma had significantly higher expression compared to EC, ChC and TER (all p <0.05), but not to YST (p = 0.84). In non-neoplastic testicular tissue the FBN-1 positivity was very low (mean QS = 0.02). Sensitivity, specificity, positive and negative predictive value of FBN-1 expression for diagnosis of GCNIS were 97.1, 98.8, 98.6 and 97.7 %.

Conclusions

FBN-1 is overexpressed in TGCTs and especially in GCNIS when compared to non-neoplastic testicular tissue in patients with germ cell tumors and could be involved in germ cell neoplasia in situ development.

Spermatogonial Nature of the Germ Cell Component of Canine Testicular Mixed Germ Cell-Sex Cord Stromal Tumours

The present study has characterized the germ cell component of canine testicular mixed germ cell-sex cord stromal tumours (MGSCTs) by examining the histological nature and histochemical and immunohistochemical features using gonocytic and spermatogonial cellular markers, c-Kit, placental alkaline phosphatase (PLAP), protein gene product 9.5 (PGP9.5), Sal-like protein 4 (SALL4), and the periodic acid-Schiff (PAS) reaction. Histologically, all 45 examples of MGSCTs were classified as spermatocytic seminomas (SSs) and Sertoli cell tumours in combination. The germ cell component of all MGSCTs was negative by PAS staining. Immunohistochemically, PLAP immunoreactivity was lacking in the germ cell component of all MGSCTs, which is not consistent with a gonocytic origin. The germ cell component was positive for PGP9.5 and SALL4 in all MGSCTs and positive for c-Kit in 53% of MGSCTs, which is consistent with the phenotype of spermatogonia. Furthermore, the germ cell component in 71% of MGSCTs had moderate immunoreactivity for SALL4, which is suggestive of a spermatogonial phenotype. Conversely, 29% of cases had a minor population of germ cells showing strong SALL4 immunoreactivity, suggesting a phenotype similar to prespermatogonia. The results suggest that the germ cell component of canine MGSCTs is morphologically classified as SS, with the majority of cases showing the spermatogonial phenotype and some cases containing a small population of prespermatogonia.

Analysis of POU5F1, c-Kit, PLAP, AP2γ and SALL4 in gonocytes of patients with cryptorchidism

Cryptorchidism is a risk factor for the development of testicular germ cell tumors (TGCTs). The most common type of TGCT in cryptorchidism is seminoma. The intratubular germ cell neoplasia unclassified (ITGCNU) is a histological pattern preceding the development of seminomas and non-seminomas. It was suggested that in patients with cryptorchidism, the gonocytes remained undifferentiated with pluripotent abilities expressing proteins like POU domain class 5 transcription factor 1 (POU5F1), tyrosine kinase receptor c-Kit, placental-like alkaline phosphatase (PLAP), the transcription factor AP2γ and sal-like protein 4 (SALL4) that confer to the gonocytes this ability and therefore make them susceptible to develop ITGCNU. The aim of the present study was to determine if the gonocytes of patients with cryptorchidism express POU5F1, c-Kit, PLAP, AP2γ and SALL4 proteins after their differentiation period. Based on this, we evaluated samples of testicular tissue from newborns to 16-year old subjects with or without cryptorchidism in search of POU5F1, c-Kit, PLAP, AP2γ and SALL4 using immunocytochemical method, the results of which were validated by RT-PCR. The results showed that control subjects witnessed a down-regulation in the expression of these five proteins in the first year of life, which eventually disappeared. On the other hand, it was determined that 21.6% (8/37) of the patients with cryptorchidism continued to express, at least, one of the proteins analyzed in this study after the second year of life. And only 5.4% (2/37) of the patients were positive to the five markers. These data sustain the proposed hypothesis that in cryptorchid patients, ITGCNU arises from gonocytes that fail in their differentiation process to spermatogonia with conservation of the proteins (POU5F1, c-Kit, PLAP, AP2γ and SALL4) that maintain pluripotency and undifferentiated characteristics and which are responsible for making the gonocytes susceptible to malignancy. However, we cannot guarantee that these patients present neoplastic transformation.

Pathogenesis of germ cell neoplasia in testicular dysgenesis and disorders of sex development

Development of human gonads is a sex-dimorphic process which evolved to produce sex-specific types of germ cells. The process of gonadal sex differentiation is directed by the action of the somatic cells and ultimately results in germ cells differentiating to become functional gametes through spermatogenesis or oogenesis. This tightly controlled process depends on the proper sequential expression of many genes and signalling pathways. Disturbances of this process can be manifested as a large spectrum of disorders, ranging from severe disorders of sex development (DSD) to - in the genetic male - mild reproductive problems within the testicular dysgenesis syndrome (TDS), with large overlap between the syndromes. These disorders carry an increased but variable risk of germ cell neoplasia. In this review, we discuss the pathogenesis of germ cell neoplasia associated with gonadal dysgenesis, especially in individuals with 46,XY DSD. We summarise knowledge concerning development and sex differentiation of human gonads, with focus on sex-dimorphic steps of germ cell maturation, including meiosis. We also briefly outline the histopathology of germ cell neoplasia in situ (GCNIS) and gonadoblastoma (GDB), which are essentially the same precursor lesion but with different morphological structure dependent upon the masculinisation of the somatic niche. To assess the risk of germ cell neoplasia in different types of DSD, we have performed a PubMed search and provide here a synthesis of the evidence from studies published since 2006. We present a model for pathogenesis of GCNIS/GDB in TDS/DSD, with the risk of malignancy determined by the presence of the testis-inducing Y chromosome and the degree of masculinisation. The associations between phenotype and the risk of neoplasia are likely further modulated in each individual by the constellation of the gene polymorphisms and environmental factors.

Is the protein expression window during testicular development affected in patients at risk for stem cell loss?

STUDY QUESTION

Is the protein expression window during testicular development affected in prepubertal patients at risk for stem cell loss?

SUMMARY ANSWER

Nuclear ubiquitin carboxyl-terminal esterase L1 (UCHL1) expression in Sertoli cells and interstitial expression of inhibin α (INHA), sex-determining region Y-box 9 (SOX9) and steroidogenic acute regulatory protein (STAR) was affected in patients with Klinefelter syndrome.

WHAT IS KNOWN ALREADY

Some patients undergoing testicular tissue banking have already been treated before the testis biopsy is taken. These treatments include chemotherapy or hydroxyurea, which can have an influence on the stem cell number and function. A germinal loss occurs in Klinefelter patients, but its cause is currently unknown.

STUDY DESIGN, SIZE, DURATION

Parrafin-embedded testicular tissue from 5 fetuses, 25 prepubertal patients and 5 adults was used to characterize the spatial and temporal distribution of different testicular marker proteins during testicular development. Expression of the markers was evaluated in germ cells, Sertoli cell and interstitial cells. The integrity of this time window was analyzed in patients at risk for germ cell loss: patients treated with hydroxyurea (n = 7), patients treated with chemotherapy (n = 6) and patients affected by Klinefelter syndrome (n = 5).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Immunohistochemistry was performed in normal fetal, prepubertal and adult testicular tissue to set up a timeline for the expression of melanoma antigen family A4 (MAGE-A4), ubiquitin carboxyl-terminal esterase L1 (UCHL1), octamer-binding transcription factor 4 (OCT4), stage-specific embryonic antigen-4 (SSEA4), homeobox protein NANOG, INHA, anti-Müllerian hormone, androgen receptor (AR), SOX9 and STAR. The established timeline was used to evaluate whether the expression of these markers was altered in patients at risk for germ cell loss (patients treated for sickle cell disease (hydroxyurea) or cancer (chemotherapy) and patients with Klinefelter syndrome).

MAIN RESULTS AND THE ROLE OF CHANCE

A protein expression timeline was created using different markers expressed in different testicular cell types. Less positive tubules and less positive cells per tubule were observed for MAGE-A4 and UCHL1 expression in the KS compared with the non-treated group (P < 0.01). Higher nuclear UCHL1 Sertoli cell expression was observed in the KS group compared with the non-treated group (P < 0.05). Higher interstitial expression of INHA (P < 0.05), SOX9 (P < 0.01) and STAR (P < 0.05) was observed in KS compared with the non-treated group.

LIMITATIONS, REASONS FOR CAUTION

Important age variations exist in the prepubertal groups. Therefore, data were represented in three age groups. However, owing to the limited access to prepubertal tissue, no statistical comparison was possible between these groups. For the Klinefelter group, tissue was only available from patients older than 12 years.

WIDER IMPLICATIONS OF THE FINDINGS

The expression timeline can add knowledge to the process of spermatogenesis and be used to evaluate altered protein patterns in patients undergoing potentially gonadotoxic treatments, to monitor spermatogenesis established in vitro and to unravel causes of germ cell loss in Klinefelter patients.

Comparative effects of di(n-butyl) phthalate exposure on fetal germ cell development in the rat and in human fetal testis xenografts

BACKGROUND

Phthalate exposure induces germ cell effects in the fetal rat testis. Although experimental models have shown that the human fetal testis is insensitive to the steroidogenic effects of phthalates, the effects on germ cells have been less explored.

OBJECTIVES

We sought to identify the effects of phthalate exposure on human fetal germ cells in a dynamic model and to establish whether the rat is an appropriate model for investigating such effects.

METHODS

We used immunohistochemistry, immunofluorescence, and quantitative real-time polymerase chain reaction to examine Sertoli and germ cell markers on rat testes and human fetal testis xenografts after exposure to vehicle or di(n-butyl) phthalate (DBP). Our study included analysis of germ cell differentiation markers, proliferation markers, and cell adhesion proteins.

RESULTS

In both rat and human fetal testes, DBP exposure induced similar germ cell effects, namely, germ cell loss (predominantly undifferentiated), induction of multinucleated gonocytes (MNGs), and aggregation of differentiated germ cells, although the latter occurred rarely in the human testes. The mechanism for germ cell aggregation and MNG induction appears to be loss of Sertoli cell-germ cell membrane adhesion, probably due to Sertoli cell microfilament redistribution.

CONCLUSIONS

Our findings provide the first comparison of DBP effects on germ cell number, differentiation, and aggregation in human testis xenografts and in vivo in rats. We observed comparable effects on germ cells in both species, but the effects in the human were muted compared with those in the rat. Nevertheless, phthalate effects on germ cells have potential implications for the next generation, which merits further study. Our results indicate that the rat is a human-relevant model in which to explore the mechanisms for germ cell effects.

An oncofetal and developmental perspective on testicular germ cell cancer

Germ cell tumors (GCTs) represent a diverse group of tumors presumably originating from (early fetal) developing germ cells. Most frequent are the testicular germ cell cancers (TGCC). Overall, TGCC is the most frequent malignancy in Caucasian males (20-40 years) and remains an important cause of (treatment related) mortality in these young men. The strong association between the phenotype of TGCC stem cell components and their totipotent ancestor (fetal primordial germ cell or gonocyte) makes these tumors highly relevant from an onco-fetal point of view. This review subsequently discusses the evidence for the early embryonic origin of TGCCs, followed by an overview of the crucial association between TGCC pathogenesis, genetics, environmental exposure and the (fetal) testicular micro-environment (genvironment). This culminates in an evaluation of three genvironmentally modulated hallmarks of TGCC directly related to the oncofetal pathogenesis of TGCC: (1) maintenance of pluripotency, (2) cell cycle control/cisplatin sensitivity and (3) regulation of proliferation/migration/apoptosis by KIT-KITL mediated receptor tyrosine kinase signaling. Briefly, TGCC exhibit identifiable stem cell components (seminoma and embryonal carcinoma) and progenitors that show large and consistent similarities to primordial/embryonic germ cells, their presumed totipotent cells of origin. TGCC pathogenesis depends crucially on a complex interaction of genetic and (micro-)environmental, i.e. genvironmental risk factors that have only been partly elucidated despite significant effort. TGCC stem cell components also show a high degree of similarity with embryonic stem/germ cells (ES) in the regulation of pluripotency and cell cycle control, directly related to their exquisite sensitivity to DNA damaging agents (e.g. cisplatin). Of note, (ES specific) micro-RNAs play a pivotal role in the crossover between cell cycle control, pluripotency and chemosensitivity. Moreover, multiple consistent observations reported TGCC to be associated with KIT-KITL mediated receptor tyrosine kinase signaling, a pathway crucially implicated in proliferation, migration and survival during embryogenesis including germ cell development. In conclusion, TGCCs are a fascinating model for onco-fetal developmental processes especially with regard to studying cell cycle control, pluripotency maintenance and KIT-KITL signaling. The knowledge presented here contributes to better understanding of the molecular characteristics of TGCC pathogenesis, translating to identification of at risk individuals and enhanced quality of care for TGCC patients (diagnosis, treatment and follow-up).

Validation of endogenous normalizing genes for expression analyses in adult human testis and germ cell neoplasms

The measurement of gene expression levels in cells and tissues typically depends on a suitable point of reference for inferring biological relevance. For quantitative (or real-time) RT-PCR assays, the method of choice is often to normalize gene expression data to an endogenous gene that is stably expressed across the samples analysed: a so-called normalizing or housekeeping gene. Although this is a valid strategy, the identification of stable normalizing genes has proved challenging and a gene showing stable expression across all cells or tissues is unlikely to exist. Therefore, it is necessary to define suitable normalizing genes for specific cells and tissues. Here, we report on the performance of a panel of nine commonly employed normalizing genes in adult human testis and testicular pathologies. Our analyses revealed significant variability in transcript abundance for commonly used normalizers, highlighting the importance of selecting appropriate normalizing genes as comparative measurements can yield variable results when different normalizing genes are employed. Based on our results, we recommend using RPS20, RPS29 or SRSF4 when analysing relative gene expression levels in human testis and associated testicular pathologies. OCT4 and SALL4 can be used with caution as second-tier normalizers when determining changes in gene expression in germ cells and germ cell tumour components, but the relative transcript abundance appears variable between different germ cell tumour types. We further recommend that such studies should be accompanied by additional assessment of histology and cellularity of each sample.