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At least 127 records · Page 7Linked to original sources
PubMed1999

BOMP/EPI intensive alternating chemotherapy for IGCCC poor-prognosis germ-cell tumors: the Spanish Germ-Cell Cancer Group experience (GG)

BACKGROUND: Patients with poor-prognosis germ-cell tumors according to the IGCCC have a poor long-term survival. This study evaluates the efficacy and toxicity of the intensive alternating chemotherapy regimen BOMP/EPI in these patients. PATIENTS AND METHODS: Patients with IGCCC poor-prognosis germ-cell tumors treated at 13 centres were studied. Treatment consisted of bleomycin 30 mg, vincristine 2 mg, methotrexate 300 mg/m2 and cisplatin 100 mg/m2 (BOMP), alternating after a 14-day interval with etoposide 120 mg/m2 day 1-4, ifosfamide 1.3 g/m2 day 1-4 and cisplatin 25 mg/m2 day 1-4 (EPI). BOMP was administered 21 days after the EPI. Bleomycin was administered weekly per 12 weeks. RESULTS: Thirty-eight patients were treated. The median number of cycles administered was 7 (1-10 cycles). Eighteen patients achieved complete responses with chemotherapy alone (12 had necrosis and 2 mature teratoma at postchemotherapy resection), and four achieved complete responses with chemotherapy and surgical resection of viable cancer. Thus, an overall favorable response was achieved in 22 patients (60%). Four additional patients had marker-negative non-resected residual masses. Eleven patients were considered treatment failures, including one who died early and another who succumbed to granulocytopenic sepsis and renal failure. Hematologic toxicity was the most common, with 26 patients (70%) having grade 4 granulocytopenia. After a median follow-up of 41 months, the actuarial two-year overall survival and progression-free survival were 64% and 58%, respectively. CONCLUSION: BOMP/EPI is active in poor-prognosis germ-cell tumors according to the IGCCC criteria. The results obtained compare favorably with those expected with conventional chemotherapy, and justify further studies.

Adolescent↗
PubMed1984

Lamellar germ cell processes: structures for possible interaction between germs cells and Sertoli cells during spermatogonial differentiation and early meiotic prophase.

The recent finding of a stage-dependent topographical relationship of basally located germ cells to Sertoli-Sertoli interspaces in the rat testis ( Ulvik 1983a ) has suggested a focal interaction between Sertoli cells and early germ cells at the sites where 2 Sertoli cells meet over a basal germ cell. Focal, stage-dependent interaction between Sertoli cells and germ cells may require specializations of the germ cell membrane. Therefore, in the present work the surface of spermatogonia and spermatocytes has been studied under the electron microscope throughout the cycle of the seminiferous epithelium. Lamellar processes, 1-3 micron long, were found to emerge from germ cells and protrude into the spaces between the overlying Sertoli cells. The processes appeared on differentiating type A spermatogonia after stage VI, on intermediate and type B spermatogonia, and on leptotene, zygotene, and early pachytene spermatocytes; however, they were not found on type A spermatogonia prior to stage VII or on preleptotene spermatocytes at stage VII. The lamellar processes are thus stage-specific and may be sites of focal interaction with the Sertoli cells. Since the cell processes always protrude into the Sertoli-Sertoli interspaces this finding supports the hypothesis of focal, stage-dependent interaction between early germ cells and Sertoli cells via the narrow Sertoli-Sertoli interspaces.

Animals↗
PubMed1988

Paracrine control of immature Sertoli cells by adult germ cells, in the rat (an in vitro study). Cell-cell interactions within the testis.

Enriched populations of germ cells prepared from adult rats were found to influence 20-day-old rat Sertoli cell secretory activity by stimulating androgen-binding protein (ABP) and inhibiting oestradiol-17 beta production in the presence of follicle-stimulating hormone (FSH) as well as of dibutyryl cyclic AMP (dbcAMP). Among the different populations tested in coculture, pachytene spermatocytes were the most effective at stimulating ABP and inhibiting oestradiol production, whereas early spermatids had relatively less effects. Cytoplasts from elongated spermatids only slightly stimulated ABP secretion. The influence of germ cells upon Sertoli cells may be mediated via paracrine component(s) detected in nonconcentrated conditioned culture media. The stimulatory (ABP) and inhibitory (oestradiol) effects of pachytene spermatocyte and early spermatid-spent media were reversible (change of media), dose related, specific (no effect of cytoplast, peritubular cell, rat liver epithelial cell or 3T3 cell-conditioned media) and strictly proportional to the cell viability estimated at the end of the incubation periods. Furthermore, the nature of the germ cell factor(s) influencing Sertoli cell secretory function is likely to be proteinaceous since both germ cell-spent media effects were trypsin and heat (100 degrees C; 3 min) sensitive and retained by molecular weight (MW) greater than 10,000 cut-off dialysis membranes. It is hypothesized that germ cells, in particular pachytene spermatocytes and early spermatids, may influence Sertoli cell function during sexual development in the rat.

Androgen-Binding Protein↗
PubMed2005

Loss of the tumor suppressor gene PTEN marks the transition from intratubular germ cell neoplasias (ITGCN) to invasive germ cell tumors.

PTEN/MMAC1/TEP1: (hereafter PTEN) is a tumor suppressor gene (located at 10q23) that is frequently mutated or deleted in sporadic human tumors. PTEN encodes a multifunctional phosphatase, which negatively regulates cell growth, migration and survival via the phosphatidylinositol 3'-kinase/AKT signalling pathway. Accordingly, Pten+/- mice develop various types of tumors including teratocarcinomas and teratomas. We have investigated PTEN expression in 60 bioptic specimens of germ cell tumors (32 seminomas, 22 embryonal carcinomas and six teratomas) and 22 intratubular germ cell neoplasias (ITGCN) adjacent to the tumors for PTEN protein and mRNA expression. In total, 10 testicular biopsies were used as controls. In the testis, PTEN was abundantly expressed in germ cells whereas it was virtually absent from 56% of seminomas as well as from 86% of embryonal carcinomas and virtually all teratomas. On the contrary, ITGCN intensely expressed PTEN, indicating that loss of PTEN expression is not an early event in testicular tumor development. The loss of PTEN expression occurs mainly at the RNA level as determined by in situ hybridization of cellular mRNA (17/22) but also it may involve some kind of post-transcriptional mechanisms in the remaining 25% of cases. Analysis of microsatellites D10S551, D10S541 and D10S1765 in GCTs (n=22) showed LOH at the PTEN locus at 10q23 in at least 36% of GCTs (three embryonal carcinoma, three seminoma, two teratoma); one seminoma and one embryonal (9%) carcinoma presented an inactivating mutation in the PTEN gene (2/22). Finally, we demonstrated that the phosphatidylinositol 3'-kinase/AKT pathway, which is regulated by the PTEN phosphatase, is crucial in regulating the proliferation of the NT2/D1 embryonal carcinoma cells, and that the cyclin-dependent kinase inhibitor p27(kip1) is a key downstream target of this pathway.

Animals↗
PubMed1995

So-called intracranial germ cell tumours: are they really of germ cell origin?

We have studied 139 cases of intracranial germ cell tumours up to the beginning of 1993, 63.3% of which showed monotypic histological patterns and 36.7% were shown to be mixed tumours. All these cases underwent surgery followed by radiation and/or chemotherapy. All cases of choriocarcinoma died within 2 years. Cases of yolk sac tumour (endodermal sinus tumour) and embryonal carcinoma also showed poor results. Mature teratoma had a 5-year survival rate (5 YSR) and 10-year survival rate (10 YSR) of 92.9% each. Immature teratoma and malignant teratoma showed a 5-YSR and 10-YSR of 75.0% each. Germinoma showed a 5-YSR of 94.7% and a 10-YSR of 91.2%. All these results may bring into question the validity of the germ cell theory, since germinoma, which should be the most undifferentiated according to the theory, was the most benign and choriocarcinoma and yolk sac tumour (endodermal sinus tumour) which should be the most differentiated, were the most malignant in the follow-up study. Therefore, germ cell tumours may not originate from one single type of cells (primordial germs cells), except for germinoma. The embryonic cells of various stages of embryogenesis may perhaps be misplaced in the bilaminar embryonic disc and become involved in the stream of lateral mesoderm at the time of the primitive streak formation and be carried to the future cranial area to be wrongly enfolded into the brain at the time of the neural tube formation. The following law may be propounded: Tumours composed of cells resembling the cells appearing in the earlier stages of embryogenesis (ontogenesis) are more malignant than those resembling the cells appearing in the later stages of embryogenesis (ontogenesis).

Brain↗
PubMed2003

Transgenic zebrafish with fluorescent germ cell: a useful tool to visualize germ cell proliferation and juvenile hermaphroditism in vivo.

Juvenile zebrafish are hermaphroditic; undifferentiated gonads first develop into ovary-like tissues, which then either become ovaries and produce oocytes (female) or degenerate and develop into testes (male). In order to fully capture the dynamic processes of germ cells' proliferation and juvenile hermaphroditism in zebrafish, we established transgenic lines TG(beta-actin:EGFP), harboring an enhanced green fluorescent protein (EGFP) gene driven by a medaka beta-actin promoter. In TG(beta-actin:EGFP), proliferating germ cells and female gonads strongly expressed EGFP, but fluorescence was only dimly detected in male gonads. Based on the fluorescent (+) or nonfluorescent (-) appearance of germ cells seen in living animals, three distinct groups were evident among TG(beta-actin:EGFP). Transgenics in ++ group (44%) were females, had fluorescent germ cells as juveniles, and female gonads continuously fluoresced throughout sexual maturation. Transgenics in +- (23%) and -- (33%) groups were males. Fluorescent germ cells were transiently detected in +- transgenics from 14 to 34 days postfertilization (dpf), but were not detected in -- transgenics throughout their life span. Histological analyses showed that 26-dpf-old transgenics in ++, +-, and -- groups all developed ovary-like tissues: Germ cells in -- group juveniles arrested at the gonocyte stage and accumulated low quantities of EGFP, while those in ++ group juveniles highly proliferated into diplotene to perinucleolar stages and accumulated high quantities of EGFP. In +- group juveniles, degenerating oocytes, gonocytes, and spermatogonia were coexistent in transiently fluorescent gonads. Therefore, the fluorescent appearance of gonads in this study was synchronous with the differentiation of ovary-like tissues. Thus, TG(beta-actin:EGFP) can be used to visualize germ cells' proliferation and juvenile hermaphroditism in living zebrafish for the first time.

Animals↗
PubMed2004

Expression of germ cell nuclear factor in mouse germ cells and sperm during postnatal period.

AIM: To assess the spatial and temporal expression of germ cell nuclear factor (GCNF) in male mouse germ cells during postnatal development and in sperm before and after capacitation. METHODS: The indirect immunofluorescence method with anti-GCNF antiserum was used to investigate the GCNF expression in mice at day 8, 10, 14, 17, 20, 28, 35, 70, and 420 after birth and in sperm before and after capacitation. RESULTS: With the proceeding of spermatogenesis, GCNF was first detected in the nuclei of spermatogonia and a few early stage primary spermatocytes at day 8, which was increased gradually at day 10 to 14 inclusive. From day 17 to day 20, the GCNF was concentrated in round spermatids, while both spermatogonia and early stage primary spermatocytes became GCNF negative. From day 28 until day 420, strong GCNF expression was shown in round spermatids and pachytene spermatocytes, while spermatogonia, early primary spermatocytes and elongating spermatids were all GCNF negative. In addition, it was also found that GCNF was localized on the acrosomal cap region of spermatozoa and there was a big change in GCNF expression during capacitation, from 98 % GCNF positive before capacitation to about 20 % positive following capacitation. The localization of GCNF in caput and cauda spermatozoa was similar. CONCLUSION: GCNF may play important roles in spermatogenesis, capacitation and fertilization.

Aging↗
PubMed1999

Testisin, a new human serine proteinase expressed by premeiotic testicular germ cells and lost in testicular germ cell tumors.

We have cloned and characterized a cDNA encoding a new human serine proteinase, testisin, that is abundantly expressed only in the testis and is lost in testicular tumors. The testisin cDNA was identified by homology cloning using degenerate primers directed at conserved sequence motifs within the catalytic regions of serine proteinases. It is 1073 nucleotides long, including 942 nucleotides of open reading frame and a 113-nucleotide 3' untranslated sequence. Northern and dot blot analyses of RNA from a range of normal human tissues revealed a 1.4-kb mRNA species that was present only in testis, which was not detected in eight of eight testicular tumors. Testisin cDNA is predicted to encode a protein of 314 amino acids, which consists of a 19-amino acid (aa) signal peptide, a 22-aa proregion, and a 273-aa catalytic domain, including a unique 17-aa COOH-terminal hydrophobic extension that is predicted to function as a membrane anchor. The deduced amino acid sequence of testisin shows 44% identity to prostasin and contains features that are typical of serine proteinases with trypsin-like substrate specificity. Antipeptide antibodies directed against the testisin polypeptide detected an immunoreactive testisin protein of Mr 35,000-39,000 in cell lysates from COS-7 cells that were transiently transfected with testisin cDNA. Immunostaining of normal testicular tissue showed that testisin was expressed in the cytoplasm and on the plasma membrane of premeiotic germ cells. No staining was detected in eight of eight germ cell-derived testicular tumors. In addition, the testisin gene was localized by fluorescence in situ hybridization to the short arm of human chromosome 16 (16p13.3), a region that has been associated with allellic imbalance and loss of heterozygosity in sporadic testicular tumors. These findings demonstrate a new cell surface serine proteinase, loss of which may have a direct or indirect role in the progression of testicular tumors of germ cell origin.

Adult↗
PubMed1998

Apoptotic response of spermatogenic cells to the germ cell mutagens etoposide, adriamycin, and diepoxybutane.

In testis, apoptosis is a way to eliminate damaged germ cells during their development. In this study, we evaluated the ability of three germ cell mutagens to induce apoptosis (or programmed cell death) at specific stages of rat seminiferous epithelial cycle. These chemicals include the cancer chemotherapy drugs etoposide and adriamycin and the butadiene metabolite diepoxybutane. According to our results, etoposide is a very potent inducer of apoptosis in male rat germ cells and the cell types most sensitive to it include all types of spermatogonia, zygotene, and early pachytene spermatocytes and meiotically dividing spermatocytes. Also, adriamycin causes an increase in apoptosis at specific stages of seminiferous epithelial cycle and the most sensitive cell types are type A3-4 spermatogonia, preleptotene, zygotene, and early pachytene spermatocytes. Diepoxybutane does not cause any significant increase in the frequency of apoptosis in rat testis. In addition, we studied whether p53 is taking part in the apoptotic response of spermatogenic cells by studying the levels of p53 protein in testis before and after chemical treatment. No accumulation of p53 in testis was seen after treatment with these three chemicals. The expression of two p53-regulated genes, p21WAF1 and mdm2, was also studied but no increase in the levels of mRNA of these genes was observed after treatment. The results indicate that apoptosis should be taken into consideration when the genotoxic effects of chemicals are evaluated in germ cells.

Animals↗
PubMed2004

Involvement of E-cadherin and beta-catenin in germ cell tumours and in normal male fetal germ cell development.

Intercellular contacts, mediated by E-cadherin, are essential for germ cell migration and maturation. Furthermore, it has been suggested that decrease or loss of E-cadherin correlates with tumour progression and invasive behaviour. beta-catenin is involved in a number of different processes, including cell--cell interaction when bound to cadherins, and determination of cell fate in pluripotent cells when activated via the Wnt signal-transduction pathway. To shed more light on the role of these factors in normal fetal germ cell development and the pathogenesis of germ cell tumours (GCTs), the present study investigated the presence and localization of E-cadherin and beta-catenin by immunohistochemistry. E-cadherin was only weakly expressed in or absent from fetal germ cells of the second and third trimesters, and was not expressed in carcinoma in situ/intratubular germ cell neoplasia unclassified (CIS/ITGCNU) and gonadoblastoma, the precursor of an invasive GCT in dysgenetic gonads. In GCTs, it was generally not expressed in seminoma and dysgerminoma, but was found in the vast majority of non-seminoma cells. beta-catenin was found in the cytoplasm of fetal germ cells at all gestational ages and in spermatogenesis in post-pubertal testes. It was also present in CIS/ITGCNU and gonadoblastoma. Whereas seminomas and dysgerminoma were negative, non-seminoma cells were frequently found to express beta-catenin. Expression of both factors therefore reflects the degree of differentiation of these tumours. No differences for either E-cadherin or beta-catenin were observed between samples of tumours resistant or sensitive to chemotherapy, and E-cadherin expression did not correlate with vascular invasion. E-cadherin and beta-catenin therefore play a role in both normal and malignant germ cell development and differentiation that warrants further investigation, but they seem to be of limited value as predictive or prognostic factors in GCTs.

Adolescent↗
PubMed1985

Germ cell tumours.

Germ cell tumours form an important group of gonadal neoplasms and are also found in a number of extragonadal sites like the mediastinum, para-pineal and sacrococcygeal regions and retroperitoneum. Although there are considerable differences between germ cell tumours occurring in different anatomical locations they exhibit a remarkable homology, and are considered as a group. In this review germ cell tumours are discussed as a group emphasizing some of the recent developments in this field. In the testis germ cell tumours form the most common group of neoplasms comprising 90% of all testicular tumours and 99% of them are malignant. In the ovary germ cell tumours comprise approximately 20% of ovarian neoplasms, and more than 90% are mature cystic teratomas and are benign. Malignant testicular neoplasms are 10 times more common than their ovarian and 20 times more common than their extragonadal counterparts. Malignant germ cell tumours have a specific age incidence and occur mainly in children and young adults. Due to this they represent one of the most important groups of neoplasms in this age group. Testicular germ cell tumours show marked racial and geographical differences occurring much more frequently in Western Europe, especially in Scandinavia, as compared with Southern and Eastern Europe. They are rare in Africa and are very uncommon in Blacks as compared to Whites. These remarkable differences are not observed in ovarian or extragonadal germ cell tumours. It is now accepted that histogenetically all the tumours in this group are of germ cell origin, and that germ cell tumours are capable of somatic (embryonal) and extra-embryonal differentiation (fig. 1). The occurrence of extragonadal germ cell tumours in anatomical locations in the midline of the body is explained on the basis of migration of the primitive germ cells during embryonic life from the wall of the yolk sac to the primitive gonad. An all embracing classification of germ cell neoplasms based on the WHO classifications of ovarian and testicular tumours is presented. The importance of careful and thorough examination of germ cell tumours is emphasized, especially in view of the recent advances in the therapy of malignant germ cell neoplasms. The value of tumour markers like alphafoetoprotein (AFP) and human chorionic gonadotropin (HCG) produced by endodermal sinus tumour (EST) and some embryonal carcinomas and choriocarcinoma and syncytiotrophoblastic giant cells respectively in diagnosis, monitoring the progress of the disease, and the efficacy of therapy, as well, as for early detection of metastases and recurrences, is strongly emphasized.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed2006

JAK/STAT signalling in Drosophila controls cell motility during germ cell migration.

The gonad is formed from two populations of cells originating at different locations: the primordial germ cells (PGCs), giving rise to either sperm or oocytes, and the somatic gonadal mesoderm precursors (SGPs), which support development of the gametes. Following the PGCs' migration during gastrulation, these two populations meet, forming the immature gonad. We present evidence that during embryonic development, the PGCs require the canonical JAK/STAT signalling cascade to migrate efficiently towards the SGPs. Loss of function for any element of the JAK/STAT pathway causes frequent germ cell mislocalisation. We have found that wild-type germ cells produce filopodia while they migrate through the mesoderm towards the gonad. Our observations suggest that PGCs use filopodia to migrate and to keep contact with each other. Interestingly, activation of the JAK/STAT pathway is required for these filopodia to form, and ectopic JAK/STAT activation enhances their formation.

Animals↗
PubMed2006

Erasure of methylation imprint at the promoter and CTCF-binding site upstream of H19 in human testicular germ cell tumors of adolescents indicate their fetal germ cell origin.

Genome-wide epigenetic modification plays a crucial role in regulating genome functions at critical stages of development. In particular, DNA methylation is known to be reprogrammed on a genome-wide level in germ cells and in preimplantation embryos, although it is relatively stable in somatic cells. In this reprogramming process, the genome becomes demethylated, and methylated de novo during later stages of development. Reprogramming of DNA methylation in male germ cells has not been fully investigated. Testicular germ cell tumors (TGCTs) possess a pluripotential nature and display protean histology from germ cells to embryonal and somatic cell differentiation. These properties make TGCT a unique model for studying germ cell development and gametogenesis in respect of DNA reprogramming. In order to obtain an insight into the epigenetic dynamics of TGCTs, we conducted a comprehensive analysis of differential methylated regions (DMRs) on H19 and IGF2 in TGCTs compared with testicular malignant lymphomas. In the present study, we show that methylation imprint at the promoter and CTCF-binding site upstream of H19 was completely erased in both seiminomatous and non-seminomatous TGCTs, whereas differential methylation was observed in testicular lymphomas. The erasure of methylation imprint was also observed in TGCTs with malignant transformation. We found biallelic unmethylation at the promoter and the CTCF-binding site upstream of H19 is required, but not sufficient for the biallelic expression of H19 in TGCTs. These data suggest that factors other than methylation contribute to transcriptional regulation of imprinted genes in TGCTs. The present data have shown that TGCTs carry distinctive epigenetic profiles at the core-imprinting domain of H19/IGF2 from other neoplasms of somatic cell origin. The data also suggest that both seminomatous and non-seminomatous TGCTs carry methylation profiles similar to fetal germ cells, but not adult germ cells, indicating the origin of TGCTs as fetal germ cells.

Adolescent↗
PubMed2002

A novel gene, Pog, is necessary for primordial germ cell proliferation in the mouse and underlies the germ cell deficient mutation, gcd.

Primordial germ cells (PGCs) are the precursor of the germ cells in adult gonads. They arise extra-gonadally and migrate through somatic tissues to the presumptive genital ridges, where they proliferate and differentiate into oogonia or spermatogonia cells. Abnormalities in this developmental process can cause embryonic depletion of germ cells leading to infertility in the adult. We report here that the mouse gcd (germ cell deficient) mutant phenotype, characterized by reduced numbers of PGCs and adult sterility, is due to reduced PGC proliferation rather than aberrant migration and is caused by the partial deletion of a single novel gene, Pog (proliferation of germ cells). Pog is critical for normal PGC proliferation, starting between 9.5 and 10.25 dpc when germ cells begin to migrate to the developing genital ridge. Deletion of Pog is also accompanied by reduced embryonic body weight and, on some genetic backgrounds, embryonic lethality. Thus, in addition to being necessary for PGC proliferation, Pog may have a wider significance in early embryonic development.

Animals↗
PubMed2001

Establishment of medaka (Oryzias latipes) transgenic lines with the expression of green fluorescent protein fluorescence exclusively in germ cells: a useful model to monitor germ cells in a live vertebrate.

We have generated transgenic medaka (teleost, Oryzias latipes), which allow us to monitor germ cells by green fluorescent protein (GFP) fluorescence in live specimens. Two medaka strains, himedaka (orange-red variety) and inbred QurtE, were used. The transgenic lines were achieved by microinjection of a construct containing the putative promoter region and 3' region of the medaka vasa gene (olvas). The intensity of GFP fluorescence increases dramatically in primordial germ cells (PGCs) located in the ventrolateral region of the posterior intestine around stage 25 (the onset of blood circulation). Whole-mount in situ hybridization and monitoring of ectopically located cells by GFP fluorescence suggested that (i) the increase in zygotic olvas expression occurs after PGC specification and (ii) PGCs can maintain their cell characteristics ectopically after stages 20-25. Around the day of hatching, the QurtE strain clearly exhibits sexual dimorphisms in the number of GFP fluorescent germ cells, a finding consistent with the appearance of leucophores, a sex-specific marker of QurtE. The GFP expression persists throughout the later stages in the mature ovary and testis. Thus, these transgenic medaka represent a live vertebrate model to investigate how germ cells migrate to form sexually dimorphic gonads, as well as a potential assay system for environmental substances that may affect gonad development. The use of a transgenic construct as a selective marker to efficiently isolate germ-line-transmitting founders during embryogenesis is also discussed.

Animals↗
PubMed2000

Stem cell factor protects germ cells from apoptosis in vitro.

Stem cell factor (SCF) plays an important role in migration, adhesion, proliferation, and survival of primordial germ cells and spermatogonia during testicular development. However, the function of SCF in the adult testis is poorly described. We have previously shown that, in the presence of SCF, there were more type A spermatogonia incorporating thymidine at stage XII of rat seminiferous tubules cultured in vitro than in the absence of SCF, implying that the increased DNA synthesis might result from enhanced survival of spermatogonia. To explore the potential pro-survival function of SCF during spermatogenesis, the seminiferous tubules from stage XII were cultured in the presence or absence of SCF (100 ng/ml) for 8, 24, 48, and 72 hours, respectively, and apoptosis was analyzed by DNA laddering and in situ 3'-end labeling (ISEL) staining. Surprisingly, not only spermatogonia, but also spermatocytes and spermatids, were protected from apoptosis in the presence of SCF. Apoptosis took place much later and was less severe in the SCF-treated tubules than in the controls. Based on previous studies showing that FSH prevents germ cells from undergoing apoptosis in vitro, and that SCF level is increased dramatically in response to FSH stimulation, we also tested if the pro-survival effect of FSH is mediated through SCF by using a function-blocking monoclonal antibody, ACK-2, to block SCF/c-kit interaction. After 24 hours of blockade, the protective effect of FSH was partially abolished, as manifested by DNA laddering and ISEL analyses. The present study demonstrates that SCF acts as an important survival factor for germ cells in the adult rat testis and FSH pro-survival effect on germ cells is mediated partially through the SCF/c-kit pathway.

Animals↗