metallothionein and Testicular-Neoplasms

Data concerning the involvement of elevated metallothionein (MT) expression in drug resistance are obviously scattered and contrasting. The presence of the MT gene product protein was screened in 51 untreated human germ cell testicular tumours, furthermore a relationship between MT expression and clinical resistance was investigated. Using monoclonal antibody and immunoenzyme staining elevated MT level could be demonstrated in nuclei and cytoplasm of both seminomas and non seminomatous germ cell testis tumours. Thirty-one tumours (61%) showed extensive, 15 (29%) focal positive staining. In contrast teratomas expressed this antigen negatively or scarcely. The highest level of MT was stated in early stages (I, IIA) compared with progressed stages (IIB, III) (p = 0.0004). Between the high level of MT and clinical resistance a converse correlation could be shown because the resistant tumours expressed no or low, while the sensitive tumours significantly high level of MT protein which can be used as an useful marker to identify patient subgroups sensitive to anticancer therapy, at least in testis tumours.

Topics: Antineoplastic Combined Chemotherapy Protocols; Carcinoma, Embryonal; Gene Expression; Germinoma; Humans; Immunohistochemistry; Male; Metallothionein; Neoplasm Staging; Seminoma; Testicular Neoplasms

Topics: Animals; Cadmium; Cisplatin; Drug Resistance; Humans; Kidney; Male; Metallothionein; Neoplasms, Experimental; Testicular Neoplasms; Urology

Increased levels of metallothionein (MT) have recently been found in the blood serum of men with newly diagnosed testicular germ cell tumors (TGCT). In light of previously published results, the aim of this study was to investigate the difference in serum MT levels among patients with different stages of TGCT and compare MT with commonly used markers (α-fetoprotein, β-human chorionic gonadotropin and lactate dehydrogenase). The concentration of total MT was determined in the serum of 25 men with TGCT (seminoma or non-seminoma) by differential pulse voltammetry. Serum samples were obtained prior to chemotherapy, after two cycles of chemotherapy and 1 year after chemotherapy. A statistically significant difference in MT levels in patients with different stages of TGCT was observed in the serum of patients with non-seminoma obtained before chemotherapy. Although not significant, an increase in serum MT levels commensurate with the disease stage increase was also observed in patients with seminomatous TGCT. The results indicate that, in combination with the existing markers, MT could be useful for the identification of the histological type of tumor and stage of the disease before biopsy diagnosis.

Topics: Adolescent; Adult; alpha-Fetoproteins; Biomarkers, Tumor; Chorionic Gonadotropin, beta Subunit, Human; Humans; L-Lactate Dehydrogenase; Male; Metallothionein; Middle Aged; Neoplasms, Germ Cell and Embryonal; Testicular Neoplasms; Young Adult

Metallothioneins (MTs) have been disclosed as a useful diagnostic factor for tumour progression and drug resistance in a variety of malignancies. Increased levels of MT in blood serum have been found in patients with several types of cancer, but there is no available information on serum MT levels in patients with testicular germ cell tumour (TGCT). The aim of the study was to determine MT levels in serum of patients with TGCT and to evaluate the portion of platinum (Pt) that binds to MT after cisplatin administration since MTs could be involved in drug resistance.. Concentration of total MT was determined in serum of 25 men with newly diagnosed TGCT by differential pulse voltammetry. The fractionation of serum was carried out by size exclusion high-performance liquid chromatography (SE-HPLC), while concentration of Pt in collected fractions was determined by inductively coupled plasma mass spectrometry.. Concentration of serum MT was significantly higher in TGCT patients than in healthy volunteers. The results of SE-HPLC analysis showed that only a small amount of Pt was bound to proteins in the area of MT elution.. Significant increase in MT levels in individuals with TGCT indicates certain health problem and, in combination with other commonly used diagnostic tools, could improve early diagnosis.

Topics: Adolescent; Adult; Antineoplastic Agents; Chromatography, Gel; Cisplatin; Humans; Male; Metallothionein; Middle Aged; Neoplasms, Germ Cell and Embryonal; Platinum; Protein Binding; Testicular Neoplasms; Young Adult

Testicular cancer is highly curable with cisplatin-based therapy, and testicular cancer-derived human embryonal carcinoma (EC) cells undergo a p53-dominant transcriptional response to cisplatin. In this study, we have discovered that a poorly characterized member of the death-associated protein family of serine/threonine kinases, STK17A (also called DRAK1), is a novel p53 target gene. Cisplatin-mediated induction of STK17A in the EC cell line NT2/D1 was prevented with p53 siRNA. Furthermore, STK17A was induced with cisplatin in HCT116 and MCF10A cells but to a much lesser extent in isogenic p53-suppressed cells. A functional p53 response element that binds endogenous p53 in a cisplatin-dependent manner was identified 5 kb upstream of the first coding exon of STK17A. STK17A is not present in the mouse genome, but the closely related gene STK17B is induced with cisplatin in mouse NIH3T3 cells, although this induction is p53-independent. Interestingly, in human cells containing both STK17A and STK17B, only STK17A is induced with cisplatin. Knockdown of STK17A conferred resistance to cisplatin-induced growth suppression and apoptotic cell death in EC cells. This was associated with the up-regulation of detoxifying and antioxidant genes, including metallothioneins MT1H, MT1M, and MT1X that have previously been implicated in cisplatin resistance. In addition, knockdown of STK17A resulted in decreased cellular reactive oxygen species, whereas STK17A overexpression increased reactive oxygen species. In summary, we have identified STK17A as a novel direct target of p53 and a modulator of cisplatin toxicity and reactive oxygen species in testicular cancer cells.

Topics: Animals; Antineoplastic Agents; Apoptosis Regulatory Proteins; Carcinoma, Embryonal; Cell Line, Tumor; Cisplatin; Drug Resistance, Neoplasm; Gene Knockdown Techniques; Humans; Male; Metallothionein; Mice; NIH 3T3 Cells; Protein Serine-Threonine Kinases; Reactive Oxygen Species; Response Elements; Species Specificity; Testicular Neoplasms; Tumor Suppressor Protein p53

Inorganic lead compounds are carcinogenic in animals and have carcinogenic potential in humans. In mice, lead (Pb) is a transplacental carcinogen in the kidney. Metallothionein (MT) is a metal-binding protein that can reduce the toxicity of various metals, including Pb, either by direct sequestration or as an antioxidant for metals that generate reactive oxygen species. Although MT appears to reduce Pb carcinogenicity in adult mice it is unknown how MT deficiency may affect Pb carcinogenicity from early life exposure. Thus, groups (n=10) of pregnant MT-I/II double knockout (MT-null) or 129/SVJ MT wild type (WT) mice were exposed to Pb acetate in the drinking water (0, 2000, 4000ppm Pb) from gestation day 8 through birth and during lactation. Maternal drinking water Pb exposure continued to wean at 4 weeks of age and the male offspring were then directly exposed to Pb until 8 weeks of age and observed until 2 years old. High dose (4000ppm) but not low dose (2000ppm) Pb reduced survival in the latter part of the study in both MT-null and WT mice. In MT-null mice, but not WT, early life Pb exposure caused a dose-related increase in testicular teratomas, to a maximum incidence of 28% compared to control (4%). Pb-induced renal cystic hyperplasia, considered preneoplastic, was a prominent occurrence in MT-null mice but nearly absent in WT mice. Pb dose-related increases in renal cystic hyperplasia occurred in adult MT-null with early life exposure with maximal incidence of 52%. Pb-treated MT-null mice also showed dose-related increases in urinary bladder hyperplasia with occasional papilloma that were absent in WT mice. Thus, MT deficiency made mice more sensitive to early life Pb exposure with regard to testes tumors, and renal and urinary bladder preneoplastic lesions.

Topics: Animals; Carcinogens, Environmental; Dose-Response Relationship, Drug; Female; Hyperplasia; Kidney Diseases, Cystic; Lead; Male; Maternal Exposure; Metallothionein; Mice; Mice, Knockout; Precancerous Conditions; Pregnancy; Prenatal Exposure Delayed Effects; Teratoma; Testicular Neoplasms; Urinary Bladder Diseases

Cisplatin (CDDP) is an extremely active drug in the treatment of germ-cell tumours. Earlier, we found an unexpected inverse correlation between the total amount of sulfhydryl groups and CDDP sensitivity in a panel of 3 human germ-cell-tumour and 3 colon-carcinoma cell lines. Major components of the sulfhydryl groups are glutathione and metallothionein (MT). We further investigated a possible role of MT in the CDDP sensitivity of germ-cell tumours. MT levels and functionality of the germ-cell-tumour and colon-carcinoma cell lines were found to be inversely correlated with CDDP sensitivity. No difference in sub-cellular localization of MT could be observed among the types of cell lines. In agreement with the in vitro data, immunohistochemical detection of MT was high in 11/14 primary human germ-cell tumours and low in 7/7 human colon carcinomas. MT-protein expression in primary germ-cell tumours did not discriminate between responding and non-responding patients. As compared with the primary tumours, MT-protein expression decreased in 5/7 post-chemotherapy residual vital tumours or remained undetectable (2/7). MT-protein expression in the germ-cell tumours was not related to total p53-protein expression. In summary, over-expression of MT was found in germ-cell tumours, both in cell lines and in human tumours. Although MT-protein over-expression seems to be associated with the CDDP sensitivity of germ-cell tumours, MT-protein expression in primary germ-cell tumours did not differ between responding and non-responding patients and therefore cannot be used to predict response to chemotherapy.

Topics: Antineoplastic Agents; Cisplatin; Colonic Neoplasms; Drug Screening Assays, Antitumor; Germinoma; Humans; Immunohistochemistry; Male; Metallothionein; Testicular Neoplasms; Tumor Cells, Cultured; Tumor Suppressor Protein p53

Prior studies show that a single subcutaneous (sc) exposure to cadmium (Cd) will induce injection site sarcomas (ISS) in rats. These tumors, thought clearly malignant, do not often metastasize or invade subdermal muscle layers because of their location. Recent evidence indicates that when tumorigenic cells chronically exposed to Cd in vitro are inoculated into mice, tumor progression and invasiveness in the mice are enhanced. Thus, we studied the effects of repeated Cd exposures on tumor incidence, progression, and metastatic potential in rats. Wistar (WF) and Fischer (F344) rats (30 per group) were injected sc in the dorsal thoracic midline with CdCl2 once weekly for 18 weeks with doses of 0, 10, 20, or 30 micromol Cd/kg. This resulted in total doses of 0, 180, 360, or 540 micromol/kg. One other group of each strain received a low, loading dose of Cd (3 micromol/kg) prior to 17 weekly injections of 30 micromol/kg (total dose 513 micromol/kg). Rats were observed for 2 years. Many F344 rats (57%) died within one week after the first injection of the highest dose, but WF rats were not affected. The low loading dose prevented acute lethality of the high dose in F344 rats. Surprisingly, latency (time to death by tumor) of ISS was the shortest in the groups given the low loading dose in both strains. ISS in these groups also showed the highest rate of metastasis and subdermal muscle layer invasion. Based on ISS incidence in the groups given the lowest total dose of Cd (180 micromoles/kg), F344 rats were more sensitive to tumor induction, showing an incidence of 37% compared to 3% in WF rats. On the other hand, Cd-induced ISS showed a higher overall metastatic rate in WF rats (18 metastatic ISS/68 total tumors in all treated groups; 27%) compared to F344 rats (6%). Immunohistochemically, the primary ISS showed high levels of metallothionein (MT), a cadmium-binding protein, while metastases were essentially devoid of MT. These results indicate that repeated Cd exposures more rapidly induce ISS. An initial low exposure to Cd further accelerates the appearance and enhances the metastatic potential and invasiveness of these tumors. The primary and metastatic ISS appear to have a differing phenotype, at least with regard to MT production. The association between multiple Cd exposures and enhanced metastatic potential of the ensuing tumors may have important implications in chronic exposures to Cd, or in cases of co-exposure of Cd with organic carcinogens, as in toba

Topics: Animals; Cadmium; Carcinogens; Disease Progression; Female; Immunohistochemistry; Male; Metallothionein; Neoplasm Metastasis; Neoplasms, Experimental; Rats; Rats, Inbred F344; Rats, Wistar; Sarcoma, Experimental; Species Specificity; Testicular Neoplasms

Inhibins and activins are dimeric proteins belonging to the transforming growth factor-beta superfamily. Follistatin is an activin-binding protein that antagonizes the function of activin via binding to its beta-subunits. Previously, we demonstrated that mice deficient in inhibin develop ovarian and testicular sex cord-stromal tumors of granulosa and Sertoli cell origin, with 100% penetrance as early as 4 weeks of age. Overproduction of activins in the serum directly causes a cachexia-like wasting syndrome that results in lethality of these mice at an early stage after the onset of the tumors. In an independent set of studies, overexpression of mouse follistatin using the mouse metallothionein I promoter in transgenic mice led to gonadal defects and eventual infertility, primarily due to local effects of follistatin in these tissues. Activin has a positive growth effect on gonadal tumor cells in culture and directly causes the cancer cachexia-like syndrome in inhibin-deficient mice via interaction with activin receptor type IIA in livers and stomachs. We therefore hypothesized that an activin antagonist such as follistatin can act as a physiological modifier, either locally or via the serum, to block the activin-mediated cancer cachexia-like syndrome in inhibin-deficient mice and/or slow the progression of gonadal cancers in these mice. To test this hypothesis, we generated mice that are homozygous mutant for the inhibin alpha null allele (i.e. inham1/inham1) and carry the mouse metallothionein I follistatin (MT-FS) transgene. Our results show that gonadal tumors that are histologically similar in most, but not all, cases to the tumors in inhibin-deficient mice develop in these inham1/inham1, MT-FS+ mice. However, inham1/inham1, MT-FS+ mice exhibit a less severe wasting syndrome, lower serum activin levels, and a statistically significant prolonged survival in a number of cases compared with mice deficient in inhibin alone. Thus, follistatin can act as a modulator of tumor growth and the activin-induced cancer cachexia-like syndrome in inhibin-deficient mice.

Topics: Activins; Animals; Disease Progression; Female; Follistatin; Glycoproteins; Inhibins; Liver Diseases; Male; Metallothionein; Mice; Mice, Transgenic; Ovarian Neoplasms; Peptides; Stomach Diseases; Survival Analysis; Testicular Neoplasms; Wasting Syndrome

The role of FSH in gonadal tumorigenesis and, in particular, in human ovarian cancer has been debated. It is also unclear what role the elevated FSH levels in the inhibin-deficient mouse play in the gonadal tumorigenesis. To directly assess the role of FSH in gonadal growth, differentiation, and gonadal tumorigenesis, we have generated both gain-of-function and loss-of-function transgenic mutant mice. In the gain-of-function model, we have generated transgenic mice that ectopically overexpress human FSH from multiple tissues using a mouse metallothionein-1 promoter, achieving levels far exceeding those seen in postmenopausal women. Male transgenic mice are infertile despite normal testicular development and demonstrate enlarged seminal vesicles secondary to elevated serum testosterone levels. Female transgenic mice develop highly hemorrhagic and cystic ovaries, have elevated serum estradiol and progesterone levels, and are infertile, mimicking the features of human ovarian hyperstimulation and polycystic ovarian syndromes. Furthermore, the female transgenic mice develop enlarged and cystic kidneys and die between 6-13 weeks as a result of urinary bladder obstruction. In a complementary loss-of-function approach, we have generated double-homozygous mutant mice that lack both inhibin and FSH by a genetic intercross. In contrast to male mice lacking inhibin alone, 95% of which die of a cancer cachexia-like syndrome by 12 weeks of age, only 30% of the double-mutant male mice lacking both FSH and inhibin die by 1 yr of age. The remaining double-mutant male mice develop slow-growing and less hemorrhagic testicular tumors, which are noted after 12 weeks of age, and have minimal cachexia. Similarly, the double-mutant female mice develop slow-growing, less hemorrhagic ovarian tumors, and 70% of these mice live beyond 17 weeks. The double-mutant mice demonstrate minimal cachexia in contrast to female mice lacking only inhibin, which develop highly hemorrhagic ovarian tumors, leading to cachexia and death by 17 weeks of age in 95% of the cases. The milder cachexia-like symptoms of the inhibin and FSH double-mutant mice are correlated with low levels of serum estradiol and activin A and reduced levels of aromatase mRNA in the gonadal tumors. Based on these and our previous genetic analyses, we conclude that elevated FSH levels do not directly cause gonadal tumors. However, these results suggest FSH is an important trophic modifier factor for gonadal tumorigenesis in

Topics: Activins; Animals; Crosses, Genetic; Female; Follicle Stimulating Hormone; Gene Expression Regulation; Hemorrhage; Homozygote; Humans; Infertility, Female; Infertility, Male; Inhibins; Male; Metallothionein; Mice; Mice, Mutant Strains; Mice, Transgenic; Oligopeptides; Ovarian Neoplasms; Ovary; Peptides; Polycystic Ovary Syndrome; Seminal Vesicles; Steroids; Testicular Neoplasms; Urinary Tract; Wasting Syndrome

Data on the involvement of elevated metallothionein (MT) expression in resistance to some of the commonly used anticancer treatments are scattered and conflicting. This encouraged us to examine further the contribution of metallothionein expression to the development of this resistance phenotype.. Formalin-fixed, paraffin-embedded blocks of primary untreated germ cell testicular tumor specimens, obtained from 77 patients following radical orchiectomy, were examined for their MT expression using monoclonal antibody and immunohistochemistry. Clinical staging, the chemotherapeutic schedule and evaluation of response to treatment (defining objective response) were performed according to UICC criteria.. All tumor types, including seminomas and nonseminomas, expressed MT, regardless of their histology and clinical stage. The immunoreactivity of MT showed a significant positive correlation with the clinical sensitivity of cancer to antitumor therapy (P = 0.0001).. In patients with germ cell testicular tumors, high MT expression, as detected by immunohistochemistry, predicts a better response rate to chemotherapy whereas tumors lacking or demonstrating low MT expression show a worse prognosis. These data do not support the hypothesis that MT overexpression contributes to cisplatinum resistance, at least in this tumor type.

Topics: Adolescent; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Humans; Immunohistochemistry; Male; Metallothionein; Middle Aged; Neoplasms, Germ Cell and Embryonal; Testicular Neoplasms; Treatment Outcome

In contrast to most other types of cancer, metastatic testicular germ cell tumours (TGCT) are cured in most patients using cisplatin-based combination chemotherapy. The biochemical mechanisms underlying this sensitivity have not been defined. Drug detoxification can modulate response to chemotherapy in vivo and in vitro, and therefore we measured levels of glutathione (GSH), glutathione-S-transferase (GST) and both constitutive and cisplatin- and dexamethasone-induced levels of metallothionein (MT) in five human testis tumour cell lines. The levels were compared with those in five human bladder cancer cell lines and two cell lines with cisplatin resistance acquired in vitro. GSH levels were relatively low in the testis tumour cell lines, as might be expected in drug-sensitive cells, and there was a 77-fold increase in GSH levels in the cisplatin-resistant testis tumour cell line. GST levels were similar in the two cell types, while metallothionein levels were relatively high in the testis tumour cell lines. These data indicate that GSH may contribute to the sensitivity of TGCT to chemotherapy, and that GSH expression may be involved in the acquisition of cisplatin resistance in these tumours.

Topics: Antineoplastic Agents; Blotting, Western; Cisplatin; Dexamethasone; Drug Resistance, Neoplasm; Germinoma; Glutathione; Glutathione Transferase; Humans; Inactivation, Metabolic; Male; Metallothionein; Testicular Neoplasms; Tumor Cells, Cultured

In this paper we demonstrate the relationship between the antitumor activity of cis-diamminedichloroplatinum (II) (CDDP) and inducibility of metallothionein (MT) and glutathione (GSH) of genitourinary tumors.. The chemosensitivity test was performed in athymic mice bearing tumors derived from the human tumor cell lines: ACHN (renal cell carcinoma), NMB-1 (urinary bladder transitional cell carcinoma), and NMT-1 (testicular embryonal cell carcinoma). A single dose of CDDP (25 mumol/kg body weight), was administered i.p. to athymic tumor bearing mice. Concentrations of platinum, MT, and GSH were measured in organ and tumor homogenates 24 h after CDDP administration.. We observed that tumors derived from NMB-1 and NMT-1 were very sensitive to CDDP, but ACHN derived tumors were resistant to CDDP. Measurement of platinum concentrations in tumor tissues revealed no correlation to the observed chemosensitivities of the tumors. Furthermore, 24 h after CDDP administration, the levels of MT and GSH in NMB-1 and NMT-1 derived tumors were lower them or equal to those of control mice. In contrast, mice bearing tumors derived from ACHN exhibited a 1.7-fold and a 2.1-fold increase in MT and GSH, respectively, as compared to control mice.. These findings suggest that the inducibility of MT and GSH in tumor tissues following CDDP administration may be a contributing factor in the development of CDDP resistance in renal cell carcinoma.

Topics: Animals; Cisplatin; Drug Resistance, Neoplasm; Glutathione; Humans; Kidney Neoplasms; Male; Metallothionein; Mice; Mice, Nude; Neoplasm Transplantation; Testicular Neoplasms; Tumor Cells, Cultured; Urinary Bladder Neoplasms; Urogenital Neoplasms

Metallothionein (MT) is an intracellular metal-binding protein which has been implicated in various biological roles, including heavy-metal detoxification and zinc and copper homeostasis, and has putative antioxidant properties. High levels of MT have been detected in certain human tumours, but its functions are unclear. The presence of tumour may cause stress conditions along with alterations in host metabolism, such as the redistribution of metals and, subsequently, in changes in hepatic MT isoforms. The distribution of basal levels of MT-1 and MT-11 isoforms in livers of different strains of mice and their induction in mice inoculated with tumour cells are investigated. While Balb-c, C57/BL and CD1 mice strains had an equal distribution of both hepatic MT isoforms, MT-I and MT-II. In addition, MT-I was the predominant isoform synthesised (> 88%) in the livers of all strains of mice at 24 h after injection with either cadmium or zinc salts. After inoculation with human testicular T7800 or T7799 tumour cells, the major form of MT induced in the livers of nude (nu/nu) mice was Zn-MT-I, and its concentration was positively correlated with the size of the inoculated tumours (r2 = 0.85). A similar positive relation was found in the livers of Balb-c mice inoculated with MM45T mouse bladder tumour cells (r2 = 0.96). Following surgical removal of T7800 tumour, hepatic MT concentrations returned to basal values. There was an increase in plasma MT levels in tumour-bearing mice and it was positively correlated with the increase in hepatic MT levels. These results demonstrate a specific increase in hepatic MT-I isoform in tumour-bearing mice, and this may be due to a generalised stress during tumour growth.

Topics: Analysis of Variance; Animals; Cell Line; Chromatography, Gel; Copper; Cytosol; Humans; Liver; Male; Metallothionein; Mice; Mice, Inbred BALB C; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Nude; Spectrophotometry, Atomic; Teratocarcinoma; Testicular Neoplasms; Transplantation, Heterologous; Tumor Cells, Cultured; Urinary Bladder Neoplasms; Zinc

Males of the MT-PVLT-10 transgenic mouse line, which expresses the polyomavirus large T-antigen under the control of the metallothionein promoter, develop testicular adenomas and display seminal vesicle enlargement. Histological analysis of adenomatous testis indicates a predominance of Leydig cells, with few normal Sertoli cells or seminiferous tubules remaining. Primary cell cultures established from the testes of control nontransgenic animals (all ages) and young MT-PVLT-10 animals (before the appearance of any phenotype) quickly entered crisis and died. In contrast, permanent cell lines could be derived from pre- and postadenomatous testes from older MT-PVLT-10 mice. All primary cultures and cell lines expressed large T-antigen. A primary culture (D-37) derived from an MT-PVLT-10 male with normal testes but enlarged seminal vesicles has been maintained for over 2 years and experiments indicate that the D-37 culture is unable to form tumors in nude mice. In contrast, a primary culture (D-4) derived from adenomatous testes of an MT-PVLT-10 mouse is also immortal, but injection of this culture into nude mice consistently resulted in tumor formation. Cloning of the D-4 culture resulted in pure Sertoli or Leydig cell clones, neither of which could form tumor upon injection into nude mice. Injection of a mixture of both cell types did result in tumor formation, suggesting a dynamic interaction between these cell types in MT-PVLT-10-induced tumorigenesis.

Topics: Animals; Antigens, Polyomavirus Transforming; Base Sequence; Biomarkers; Cell Line; Cells, Cultured; Chlorocebus aethiops; Culture Techniques; DNA Primers; Leydig Cells; Male; Metallothionein; Mice; Mice, Nude; Mice, Transgenic; Molecular Sequence Data; Polymerase Chain Reaction; Promoter Regions, Genetic; Sertoli Cells; Testicular Neoplasms; Testis; Transfection; Transplantation, Heterologous

Metallothioneins (MT) are endogenous metalloproteins involved in the homeostasis of essential metals and detoxification of toxic metals. Some recent experimental studies suggested tumor resistance to cisdiamminedichloroplatin may be associated with overexpression of MT in the tumor.. The presence of MT in 33 primary testicular germ cell tumor specimens was assessed immunohistochemically using a rabbit polyclonal rat liver MT antibody that cross-reacted with human MT. The data were correlated with the patients' clinical course.. Seminomas stained weakly or not at all for MT, regardless of the clinical stage. Most nonseminomas stained heavily for MT. The more advanced staged nonseminomas tended to stain more heavily for MT.. In view of the considerable experimental evidence as well as some inferential clinical data involving MT in cis-diamminedichloroplatin resistance, there appears to be a role for MT in cis-diamminedichloroplatin resistance in germ cell tumors. Further studies to elucidate the role of MT in germ cell tumor chemoresistance are warranted.

Topics: Cisplatin; Drug Resistance; Germinoma; Humans; Immunohistochemistry; Male; Metallothionein; Neoplasm Staging; Testicular Neoplasms

The true rate-limiting step in steroidogenesis is the delivery of cholesterol to the inner mitochondrial membrane where it is converted to pregnenolone by the cholesterol side-chain cleavage complex. This process is known to require de novo protein synthesis. We have previously described the synthesis of a family of 37, 32, and 30 kilodalton mitochondrial proteins in response to hormone stimulation in MA-10 mouse Leydig tumor cells and have proposed that these proteins are involved in the acute regulation of steroidogenesis. In this study we have used two subclones of MA-10 cells to further demonstrate the correlation between the quantity of these proteins and the production of steroids in response to hormone treatment. One of these, designated MA-10(K3), has been transfected with a mutant gene of the type 1 regulatory subunit of the cAMP-dependent protein kinase under the control of a metallothionein promoter, whereas the other, designated MA-10(P+29), is a constitutive overproducer of a cAMP-phosphodiesterase (PDE). MA-10 parent cells designated (P), produce large amounts of progesterone in response to LH, human CG, and (Bu)2cAMP. The MA-10(K3) cells, on the other hand, whereas significantly higher than controls, produce much less steroid than the parent cells in response to hormone stimulation. Activation of the mutant gene with Zn+2 results in yet a further decrease in the amount of steroid produced. The MA-10(P+29) cells display greatly reduced progesterone production when stimulated with LH, because of the presence of high amounts of PDE, but return to maximally stimulated levels when a PDE inhibitor is present. Quantitation of the synthesis of the mitochondrial proteins described above in MA-10(K3) cells in the presence and absence of Zn+2 and in MA-10(P+29) cells in the presence and absence of PDE inhibitor clearly demonstrate that the amount of the 30 kilodalton mitochondrial proteins present in these cells closely parallels that of progesterone production. The high degree of correlation between the appearance and quantity of these mitochondrial proteins and the production of steroids make them strong candidates for the putative proteins involved in acute regulation of steroidogenesis.

Topics: 3',5'-Cyclic-AMP Phosphodiesterases; 4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone; Animals; Bucladesine; Chorionic Gonadotropin; Clone Cells; Electrophoresis, Gel, Two-Dimensional; Electrophoresis, Polyacrylamide Gel; Gentamicins; Kinetics; Leydig Cell Tumor; Luteinizing Hormone; Male; Metallothionein; Mice; Mitochondria; Molecular Weight; Progesterone; Promoter Regions, Genetic; Protein Biosynthesis; Protein Kinases; Proteins; Testicular Neoplasms; Transfection; Tumor Cells, Cultured; Zinc

The presence of high levels of metallothionein (MT) in developing mammalian cells is well documented. It has been suggested that the developmental profile and gene expression of MT is similar to that of the so-called oncodevelopmental gene products such as a-fetoprotein. In this study tissue sections of nine human embryonal carcinomas of the testis were tested by means of the avidin-biotin peroxidase complex for the presence of MT. The antigen was localized in variable amounts in the cytoplasm and nucleus in tumour cells in all cases. There was evidence that immunoreactivity was related to the histological growth pattern of tumour cells. These findings suggest that MT may be considered an oncodevelopmental product which could be useful as a tumour marker. In addition, the histology of these tumours might predict MT expression; this may prove of value in testing the hypothesis of MT-related emergence of drug-resistant cell lines in the course of treatment of tumours with metal-containing chemotherapeutic agents.

Topics: Adolescent; Adult; Cross Reactions; Humans; Immunohistochemistry; Male; Metallothionein; Teratoma; Testicular Neoplasms

The ability of zinc acetate to modify the carcinogenic effects of CdCl2 in male Wistar [Crl:(WI)BR] rats was studied over a 2-year period. Groups of rats received a single s.c. injection of Cd (30.0 mumol/kg) in the dorsal thoracic midline or i.m. in the right thigh at time 0. Zinc was given in three separate s.c. doses of 0.1, 0.3, or 1.0 mmol/kg (at -6, 0, and +18 h relative to cadmium) in the lumbosacral area or p.o. at 100 ppm in the drinking water (-2 to +100 weeks). Cadmium treatments (s.c.) resulted in the appearance of tumors at the injection site and in the testes. The incidence of s.c. injection site tumors (mostly mixed sarcomas) was markedly reduced by high dose (1.0 mmol/kg) s.c. zinc (50% reduction) and was almost abolished by p.o. zinc (92% reduction). Testicular tumors (mostly Leydig cell adenomas) induced by s.c. cadmium were reduced in a dose-related fashion by zinc and were found to be highly dependent on the ability of zinc to prevent the chronic degenerative effects of cadmium in the testes. Oral zinc had no effect on s.c. cadmium-induced testicular tumors, while i.m. cadmium alone did not induce these tumors. In rats in which s.c. cadmium-induced testicular tumors and chronic degenerative effects were prevented by zinc (1.0 mmol/kg, s.c.), a marked elevation in prostatic tumors (exclusively adenomas) occurred (control, 9.6%; cadmium plus high zinc 29.6%). Cadmium given i.m., which did not result in testicular tumors or degeneration, also induced an elevated incidence (42.3%) of prostatic tumors, again indicating a dependence on testicular function. Prostatic tumor incidence was also significantly elevated (25.0%) in rats receiving 1.0 mmol/kg zinc, s.c., in combination with i.m. cadmium. These results indicate that zinc inhibition of cadmium carcinogenesis is a complex phenomenon, depending not only on dose and route but also on the target site in question.

Topics: Animals; Cadmium; Dose-Response Relationship, Drug; Injections, Subcutaneous; Male; Metallothionein; Prostatic Neoplasms; Rats; Rats, Inbred Strains; Sarcoma, Experimental; Skin Neoplasms; Testicular Neoplasms; Zinc

Cadmium (Cd) induces testicular tumors of interstitial cell (IC) origin in rats which can be prevented by zinc (Zn). Zn-induced synthesis of metallothionein (MT), a metal-binding protein with a high affinity for Cd, is thought to account for tolerance to Cd in most tissues by sequestration of Cd. However, the mechanism of Zn inhibition of Cd-induced carcinogenesis in the testes is unknown. Our studies with ICs obtained by collagenase dispersion of rat testes, indicate the levels of the Cd-binding protein in ICs are unaltered by Zn. This testicular protein also was found to differ from MT in amino acid content and to have a lower affinity for Cd. Thus, MT does not seem to be involved in protection of ICs against Cd carcinogenesis. Altered Cd toxicokinetics as a possible explanation for Zn-induced tolerance was therefore explored. Cd uptake into isolated ICs had passive diffusion and nonpassive (carrier mediated or active transport or both) components. The nonpassive component of Cd accumulation was markedly reduced by addition of Zn in vitro, indicative of competition for uptake at the cellular level. These results indicate that toxicokinetic alterations leading to reduced Cd accumulation may play an important role in Zn induction of tolerance to Cd carcinogenesis in the testes.

Topics: Animals; Cadmium; Chromatography, High Pressure Liquid; Ethylmaleimide; Leydig Cell Tumor; Leydig Cells; Liver; Male; Metallothionein; Potassium Cyanide; Rats; Rats, Inbred Strains; Testicular Neoplasms; Testis; Zinc