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R Oyasu

Publications and source records attributed to R Oyasu.

At least 73 records · Page 4Linked to original sources
PubMed1993

Immunohistochemical localization of epidermal growth factor and transforming growth factor alpha in the male rat accessory sex organs.

We examined the presence of epidermal growth factor (EGF) and transforming growth factor alpha (TGF alpha) in the prostate (ventral, lateral, dorsal lobes), coagulating gland and seminal vesicle of Fisher 344 adult male rats by immunohistochemical and radioimmunoassay methods. Immunohistochemically demonstrable EGF was localized in the luminal secretion only of the dorsal lobe of the prostate. Reactive TGF alpha was localized in the lateral lobe (100% of epithelial cells), dorsal lobe (about 40% of the epithelial cells) and seminal vesicle (100% of epithelial cells), but not in the coagulating gland or ventral lobe of the prostate. Radioimmunoassay also demonstrated a measurable amount of TGF alpha in the lateral lobe (194 pg./gm. wet weight) and seminal vesicle (74 pg./gm.). Assayable EGF was demonstrated at much higher levels in all prostate lobes (ranging from 1.2 micrograms./gm. wet weight in the ventral lobe to 26.4 micrograms./gm. in the dorsal lobe) and wet weight in the ventral lobe to 26.4 micrograms./gm. in the dorsal lobe) and the seminal vesicle (0.9 micrograms./gm.). This is the first report describing the presence of immunoreactive TGF alpha and EGF in the male accessory sex organs.

Animals↗
PubMed1993

A new in vivo model for studying invasion and metastasis of rat and human bladder carcinomas.

The biological potential of tumor cells is best evaluated at the organ site orthotopic to the tumor cells. Recent studies have documented site-specific differences in the potential of tumor cell growth. However, orthotopic implantation of bladder cancer cells into bladders of nude mice only resulted in a low tumor yield. We have developed a new model that consists of a rat bladder transplanted into the retroperitoneal space and connected to a reservoir s.c. placed in a nude mouse. Rat malignant bladder cancer cells (MYU3L and LMC19) transfected with the human growth hormone (hGH) gene as a biomarker were introduced into the transplanted bladder by percutaneous puncture of the attached reservoir. Successful uptake was indicated by a progressive rise in the hGH level in the bladder aspirate. When examined at 6-16 weeks post transplantation, all mice that had received MYU3L (n = 6) or LMC19 (n = 6) cells were found to have invasive carcinomas. MYU3L was highly invasive, forming multiple peritoneal implants, but was not metastatic. LMC19 was deeply invasive and metastasized to the retroperitoneal and subclavian lymph nodes and the lungs (4/6). Of two human bladder cancer cell lines (RT4 and T24) tested, RT4 formed multiple minute papillary tumors in five of six bladders, two of which were minimally invasive to the muscle layer. T24 cells formed only one to two small tumors in three of six bladders, and these were confined to the lamina propria. This system appears promising for studies of the mechanism of tumor invasion and metastasis and for evaluation of antineoplastic agents.

Animals↗
PubMed1992

Marked enhancement of rat urinary bladder carcinogenesis by heat-killed Escherichia coli.

Chronic urinary tract infection is an important risk factor for the development of carcinoma in the human urinary bladder. To test the effect of chronic persistent inflammation on bladder carcinogenesis, we instilled heat-killed Escherichia coli (1 x 10(8) cells suspended in 0.5 ml of phosphate-buffered 2.1% NaCl solution) twice a week into the heterotopically transplanted rat urinary bladders in which carcinogenesis was initiated by a single dose (0.25 mg) of N-methyl-N-nitrosourea. When compared with the control animals, the rats treated with killed E. coli showed significantly enhanced bladder tumorigenesis, as reflected by an increase in the incidence of tumor (P = 0.05) and a 6- to 40-fold increase in the number of tumors per bladder (P less than 0.0001). The tumors were characterized by intraepithelial clusterings of neutrophils and by chronic inflammation and marked capillary proliferation in the tumor stroma. All of these features were rare in tumors in the control groups. The accelerated cell proliferation induced by killed E. coli treatment appears to play a significant role in the enhancement of tumorigenesis.

Administration, Intravesical↗
PubMed1992

Tumorigenic transformation and neoplastic progression of human uroepithelial cells after exposure in vitro to 4-aminobiphenyl or its metabolites.

A multistep in vitro/in vivo transformation system was used to test the transforming effect(s) of the human bladder procarcinogen 4-amino-biphenyl (ABP) and two putative proximate carcinogenic metabolites, N-hydroxy-4-aminobiphenyl (N-OH-ABP) and N-hydroxy-4-acetylamino-biphenyl (N-OH-AABP), on a clonally derived nontumorigenic SV40-immortalized human uroepithelial cell line, SV-HUC. SV-HUC were exposed in vitro to concentrations of ABP, N-OH-ABP, or N-OH-AABP that caused a range of cytotoxicity from 5 to 76%. Tumorigenic transformation of SV-HUC, as assessed by the ability of the exposed cells to form carcinomas when inoculated s.c. into athymic nude mice, was achieved after a single exposure to ABP, N-OH-ABP, or N-OH-AABP. In the tumorigenic transformation experiments, 28 of 45 mice representing all 15 carcinogen-exposed observation groups formed carcinomas, whereas none of 9 mice from control groups formed carcinomas (P = 0.001). Neoplastic progression of a low grade regressive squamous cell carcinoma, MC-T11, was also achieved in this system after in vitro exposure to ABP, N-OH-ABP, or N-OH-AABP. In these progression experiments, 11 of 33 mice representing 7 of 12 carcinogen-exposed observation groups formed persistent, high grade nongressing tumors, while only 1 of 19 untreated MC-T11 controls spontaneously progressed on reinoculation (P = 0.022). Forty independent carcinomas generated in athymic nude mice recapitulated diverse cancer phenotypes (including different growth kinetics and histopathological subtypes and grades) represented in clinical bladder cancers. These results demonstrate for the first time the transforming effects of the potent human carcinogen ABP and two of its proximate N-hydroxy metabolites on a prime human target cell type, HUC.

Aminobiphenyl Compounds↗
PubMed1992

Clonal origin of bladder cancer.

BACKGROUND: Patients with cancer of the urinary bladder often present with metachronous tumors, appearing at different times and at different sites in the bladder. This observation has been attributed to a "field defect" in the bladder that allows the independent transformation of epithelial cells at a number of sites. We tested this hypothesis using molecular genetic techniques. METHODS: We examined 13 tumors from cystectomy specimens from four women, using a method that analyzes the pattern of X-chromosome inactivation to determine whether the tumors were derived from the same precursor cell. In addition, we analyzed allelic loss on autosomes to determine whether different tumors had the same genetic alterations. The alterations evaluated included the loss of chromosome 9q sequences (commonly found in superficial bladder tumors) and the loss of 17p and 18q sequences (usually found only in advanced tumors). RESULTS: For each patient studied, all the tumors had inactivation of the same X chromosome, whereas normal bladder mucosa cells had random patterns of inactivation. Moreover, each tumor that could be evaluated from a given patient had lost the same allele on chromosome 9q, suggesting that the loss of this allele preceded the spread of neoplastic cells elsewhere in the bladder. The losses of chromosome 17p and 18q alleles, which are late events in tumor progression, were not common to different tumors from the same patient. CONCLUSIONS: A number of bladder tumors can arise from the uncontrolled spread of a single transformed cell. These tumors can then grow independently with variable subsequent genetic alterations.

Alleles↗
PubMed1992

Neoplastic progression by EJ/ras at different steps of transformation in vitro of human uroepithelial cells.

The biological effects of expression of mutant ras at different stages of human uroepithelial cell (HUC) tumorigenesis were tested after transfection of EJ/ras into nonestablished HUC and three isogeneic cell lines representing different steps in HUC transformation in vitro. Transfection with EJ/ras failed to immortalize diploid HUC and also failed to cause tumorigenic conversion of a near-diploid SV40-immortalized HUC line (SV-HUC) except at one of six nude mouse inoculation sites. In contrast, EJ/ras-transfected aneuploid low-grade squamous cell carcinoma cells formed undifferentiated, invasive carcinomas at four of six inoculation sites. Furthermore, EJ/ras accelerated tumor growth in MC-ppT11-HA2, an aneuploid high-grade transitional cell carcinoma line, as determined by decreased tumor latent periods and doubling times. These results suggest that EJ/ras contributes to progression, possibly by accelerating tumor growth, but does not in itself cause tumorigenic transformation of uroepithelial cells. To test whether chromosome losses accompanied EJ/ras transformation of SV-HUC, the karyotype of the one SV-HUC tumorigenic transformant obtained (above) was examined. This tumor cell line showed losses of chromosome arms 3p, 10p, 11p, and 18, all of which have been hypothesized to contain genes that suppress cancer development. Therefore, these results also provide new evidence suggesting that genetic losses may be required for mutant ras to contribute to HUC tumorigenic progression.

3T3 Cells↗
PubMed1992

Flow cytometric analysis of small renal tumors.

Flow cytometric deoxyribonucleic acid (DNA) content analysis was performed on 26 renal tumors 3.0 cm. or less in maximum diameter. We noted DNA aneuploid cell populations in 8 of 25 tumors (32%) evaluable for DNA ploidy status. DNA aneuploid cells comprised 7 to 59% of the cells in those tumors. In comparison, 12 of 25 tumors (48%) larger than 3.0 cm. had aneuploid cell populations. S phase cell populations were significantly increased in the small aneuploid tumors compared with the small diploid tumors (p < 0.001). We believe that these small tumors have the potential to behave aggressively and, therefore, they should be treated no differently than larger renal neoplasms.

Adult↗
PubMed1992

Effect of epidermal growth factor/transforming growth factor alpha and transforming growth factor beta 1 on growth in vitro of rat urinary bladder carcinoma cells.

The response to growth factor stimulation was evaluated in clonally derived rat bladder carcinoma cell lines, ranging from nontumorigenic to tumorigenic and metastatic, in athymic nude mice. In the nontumorigenic cell line D44c, epidermal growth factor (EGF)/transforming growth factor (TGF) alpha weakly stimulated anchorage-dependent, but not -independent, growth. In tumorigenic/nonmetastatic cells (G1-200 Cl-17), EGF/TGF-alpha stimulated markedly anchorage-independent, but marginally anchorage-dependent growth, whereas TGF-beta 1 inhibited anchorage-independent growth and DNA synthesis. In the highly tumorigenic/metastatic cell line LMC19, EGF/TGF-alpha stimulated anchorage-dependent growth weakly and anchorage-independent growth strongly. In these cells, TGF-beta 1 did not inhibit anchorage-independent growth and DNA synthesis but increased the size of colonies irrespective of the presence of EGF, and some cells were scattered around colonies in soft agar. None of the cell lines showed evidence of TGF-alpha-specific mRNA transcription. Expression of TGF-beta 1 mRNA increased in parallel to the biological aggressiveness of the cell lines. Highly tumorigenic and metastatic cells also demonstrated gelatinase activity involving 72 kilodalton and 92 kilodalton types. Our data suggest that the growth-stimulatory effect of EGF/TGF-alpha in soft agar may be limited to cells that are already tumorigenic and that EGF/TGF-alpha is not effective in making nontumorigenic cells become tumorigenic (or in making nontumorigenic cells grow in soft agar).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Tumor-promoting effect of urinary epidermal growth factor in rat urinary bladder carcinogenesis.

We previously demonstrated that the specific component of rat urine designated as Fraction I (Fr.I), which has been known to enhance carcinogenesis in the rat urinary bladder, contains epidermal growth factor (EGF) and transferrin (TF). The present study was designed to determine whether EGF or TF is responsible for the tumor-enhancing effect of Fr.I. The heterotopically transplanted rat urinary bladder (HTB), which has been developed in our laboratory, was used for the study. Fr.I was prepared from normal rat urine by a method published previously. Fr.I deficient in EGF or TF was prepared by passing this fraction through an Affi-Gel Hz column coupled with anti-rat EGF or TF antibodies, respectively. EGF and TF eluted from the column (designated as eluted EGF and eluted TF) were also tested for tumor-enhancing activity. Fr.I passed through the column coupled with nonimmune rabbit IgG served as control (Fr.I column control). After initiation of carcinogenesis in HTBs by instillation of a single dose of 0.25 mg of N-methyl-N-nitrosourea, test materials were administered into these HTBs once a week for 30 weeks. The results showed that removal of EGF significantly reduced the tumor-enhancing effect of Fr.I (P less than 0.001 as compared to that of the Fr.I column control) and that eluted EGF by itself significantly enhanced the carcinogenesis as compared to that of the vehicle control (P less than 0.006). Removal of TF from Fr.I also reduced the tumor-enhancing effect of Fr.I (P less than 0.01). However, removal of both EGF and TF from Fr.I did not enhance the inhibitory effect demonstrated by the Fr.I which was deficient in EGF. Likewise, combined use of TF and EGF did not exceed the tumor-promoting effect of EGF. The results indicate that EGF in Fr.I may play a significant role in the promotion of bladder carcinogenesis by urine.

Animals↗
PubMed1991

Nonrandom chromosome losses in stepwise neoplastic transformation in vitro of human uroepithelial cells.

An in vitro/in vivo transformation system was used to study chromosome region losses in stepwise neoplastic transformation and progression of human uroepithelial cells. Complete cytogenetic analyses were done on 17 independent carcinomas derived using this system and showed that losses of chromosome regions on 3p (P = 0.0003), 6q (P = 0.01), and 18q (P = 0.0003) were nonrandom. The smallest common losses [i.e., 3(p13----pter), 6(q21----q23), and 18(q21.1----qter)] were in putative cancer suppressor gene regions. In addition, cumulative losses from a group of 10 chromosome arms (i.e., 1p, 1q, 3p, 5q, 6q, 9q, 11p, 13q, 17p, and 18q) frequently deleted in clinical carcinomas were very significant (P = 0.0005) compared to losses from all other arms. Loss of 3p and 18q both correlated with transformation to high grade carcinomas (P = 0.001 and P = 0.004, respectively). These data provide new evidence supporting hypotheses that chromosome regions 3(p13----pter) and 6(q21----q23) contain genes that suppress cancer development. These results also provide new data confirming the hypothesis that genetic loss(es) in the 18(q21.1----qter) region are associated with the development of high grade malignancies.

Carcinoma, Transitional Cell↗
PubMed1991

Specific chromosome change associated with acquisition in vivo of tumorigenicity in carcinogen-induced rat urinary bladder carcinoma cells.

The correlation between chromosomal changes and tumorigenic potential of rat bladder epithelial cells was investigated. Seven cell lines were established from neoplastic urothelial cells derived from heterotopically transplanted rat bladders treated with topical application of one of two carcinogens, N-methyl-N-nitrosourea (MNU) or N-hydroxy-N-glucuronosyl-2-aminofluorene. Loss of the short arm of chromosome 3 was demonstrated in three of four lines tumorigenic in the nude mouse, but in none of three nontumorigenic lines. One of the three nontumorigenic cell lines (D44c) was treated further in vitro with MNU. All six tumorigenic, but none of the four nontumorigenic, morphologically altered cell lines derived from D44c demonstrated loss of the short arm of chromosome 3. These results suggest that chromosome 3 alterations may be associated with the tumorigenicity of carcinogen-induced rat bladder epithelial cells.

Animals↗
PubMed1991

Desmoplakin expression and distribution in cultured rat bladder epithelial cells of varying tumorigenic potential.

The expression and distribution of the desmosomal plaque proteins, desmoplakins (DPs) I and II, were studied in nontumorigenic (RBE-8) and a series of tumorigenic (AY34, R-4909, SS-24B, RBTCC-8, and 804G) rat bladder epithelial cell lines. These cell lines ranged from slow-growing papillary transitional cells (AY34) to rapidly metastatic carcinoma cells (RBTCC-8). DPs I and II were shown by immunoblotting and Northern analysis to be present in nontumorigenic RBE-8 cells as well as in all of the tumorigenic cell lines, albeit in differing amounts. Immunofluorescence microscopy revealed striking differences in DP distribution, corresponding in general with increases in tumorigenic potential. Whereas DPs of normal RBE-8 cells and less tumorigenic AY34 cells were localized predominantly at cell interfaces, the more tumorigenic lines exhibited a high proportion of DP in the form of cytoplasmic dots, a distribution reminiscent of that seen in epithelial cells maintained in low levels of extracellular calcium. In 804G cells, which represented the most extreme example of this phenomenon, the majority of DPs were organized as cytoplasmic dots. Electron microscopy revealed intermediate filament (IF)-associated spots in the cytoplasm as well as an elaborate array of IF-associated plaques at the cell-substratum interface. The IF-associated spots in the cytoplasm reacted with anti-DP antibody in immunogold labeling experiments while those at the cell-substratum did not react. In more dense cultures of 804G cells, certain cells stratified and expressed increased amounts of DP followed by the induction of new keratins including those of the skin type. Decreasing extracellular calcium resulted in a rearrangement of DP in each cell line; staining at cell-cell interfaces disappeared and was replaced with a pattern of cytoplasmic dots. These results demonstrate a possible relationship between desmosome assembly and/or maintenance and tumorigenic potential.

Animals↗
PubMed1991

Prostate-type gland in the epididymis.

We confirmed the presence of a prostate-type gland in the epididymis of a 30-year-old white man by immunohistochemical analysis using prostate specific antigen and prostate specific acid phosphatase. We suggest possible histogenetic mechanisms for such previously undescribed morphological heterogeneity within this wolffian duct derivative.

Adult↗
PubMed1991

ras gene alterations in invasive and non-invasive rat bladder carcinomas induced by N-methyl-N-nitrosourea.

We have established a reliable method to induce invasive and non-invasive carcinomas in the heterotopically transplanted urinary bladder of rats by repeated injection of N-methyl-N-nitrosourea (MNU), and examined the alterations of the ras oncogenes and ras oncogene product (p21) in the induced tumours. The incidence of muscle-invasive carcinomas was proportional to the total dose of MNU. When 5, 6 or 12 doses of MNU were used, muscle invasive carcinomas developed in 22, 58 or 45% of animals, respectively, after a mean observation period, respectively, of 54 +/- 9, 45 +/- 13 and 38 +/- 3 weeks. Whereas activated H-ras gene was detected in only one non-invasive carcinoma by DNA transfection assay, seven of 18 non-invasive and invasive carcinomas showed activated ras p21 when examined by immunoblot analysis. Amplification or rearrangement of myc or epidermal growth factor (EGF) receptor gene was not observed. The results indicate that alterations of ras gene may be involved in the development of rat bladder carcinomas but not of invasiveness.

Animals↗
PubMed1991

Urothelial leiomyomatous hamartoma of the kidney.

A 34-year-old woman presented with a renal pelvic mass. A nephroureterectomy including a cuff of bladder, was performed and pathologic examination revealed a hamartoma involving the renal parenchyma and pelvis. The pelvic portion of the tumor was composed of papillae lined by urothelium; the parenchymal portion of the tumor was composed of tubules within a fibromuscular stroma. The authors propose that this is a distinct entity not previously described in the literature.

Adult↗
PubMed1991

Multilocular cystic renal cell carcinoma.

Multilocular cystic renal cell carcinoma (MCRCC) appears to be a distinct subtype of renal cell carcinoma with characteristic gross and microscopic features. The authors' ten-year experience (1977-1987) included six cases of MCRCC that were followed for a minimum of two years, with neither recurrence nor metastasis observed in any of the cases. During this period, there were 855 urologic procedures for the upper urinary tract, with 256 neoplasms or cysts identified. These included 32 simple cysts, 41 transitional cell carcinomas, 133 renal cell carcinomas, 17 papillary renal cell carcinomas, and 33 miscellaneous tumors. Histologically, the MCRCCs were well-demarcated multicystic lesions containing variably sized aggregates of neoplastic clear cells showing grade 1 nuclear features and little or no mitotic activity. The cyst walls were densely fibrotic, and the lining was often devoid of epithelium. Flow-cytometric analysis performed in five of the six cases with the use of paraffin-embedded tissue showed the tumors to be diploid in all instances, with low proliferative activity. The authors believe that this tumor is a low-grade variant of renal cell carcinoma and should be studied further to determine appropriate therapy.

Aged↗
PubMed1991

Enhancement of N-nitroso(2-hydroxypropyl)(2-oxopropyl)amine-induced tumorigenesis in Sprague-Dawley rats by orotic acid.

The effect of orotic acid (OA) on the carcinogenicity of N-nitroso(2-hydroxypropyl)(2-oxopropyl)amine (HPOP) in rats was evaluated. A group of 5 week old Sprague-Dawley male rats were placed on a synthetic 20% protein diet containing 1% OA. A second group was placed on a regular, OA-free diet of similar composition. Approximately 2 weeks later, animals from both groups grown to 100 g were treated with 400 mg/kg HPOP delivered continuously for 14 days via 2002 Alzet osmotic pumps implanted s.c. Rats fed the OA diet were kept under this diet for 13 weeks following initiation of HPOP treatment and subsequently were placed on the regular diet for another 12 weeks, at which time they were killed. In the absence of OA, HPOP-treated rats developed adenomas in the kidney and lungs at incidences of 5 and 33% respectively, while pancreas and liver were unaffected. On the other hand, rats fed the OA diet and treated with HPOP developed renal mesenchymal tumors and pulmonary adenomas at incidences of 70 and 65% respectively. In addition, HPOP induced cystic lesions in the pancreas of animals fed the OA diet. The enhancement of the tumorigenic effectiveness of HPOP was at least partly ascribed to the effect of OA treatment on the rate by which carcinogen-induced alkylation of DNA was repaired in various tissues. Accumulation of N7-methylguanine in kidney, lung and pancreas of rats fed the OA diet was 1.6, 1.9 and 2.4 times higher than in respective organs of animals fed the regular diet. Similarly, concentrations of the premutagenic O6-methylguanine (O6-MeG) were 3.0, 3.1 and 2 times greater in the kidney, lung and pancreas of rats fed the OA diet than in the respective organs of those fed the regular diet. Feeding an OA diet to HPOP-treated rats did not have an effect on either the resistance of the liver to this carcinogen or on the level of O6-MeG accumulation in the DNA of this tissue.

Animals↗