Long-term transplantability and morphological stability of three experimentally induced urinary bladder carcinomas in rats. (1/4713)

Three transitional cell carcinomas induced in Fischer 344 rats by a methylcholanthrene pellet or a foreign body inserted locally into the bladder have been serially transplanted in the syngeneic strain for up to 6.5 years. There have been no changes in the individual morphological characteristics of the tumors during this time. Cells cultured in vitro for varying numbers of passages reproduce regularly the morphology of each tumor when they are injected back into the animals and results from a microcytotoxicity assay for cellular immunity indicate that they retain a common, bladder tumor-specific antigen. These tumors are useful for research in turmo biology and are offered to other scientists seeking transplantable carcinomas for experimentation.  (+info)

Natural history of papillary lesions of the urinary bladder in schistosomiasis. (2/4713)

Variable epithelial hyperplasia was observed in urinary bladder of nine capuchin monkeys (Cebus apella) when examined at cystotomy 94 to 164 weeks after infection with Schistosoma haematobium. These hosts were followed for 24 to 136 weeks postcystotomy to determine the status of bladder lesions in relation to duration of infection and to ascertain whether lesion samples removed at cystotomy reestablished themselves in autologous and heterologous transfers. There was involution of urothelial hyperplasia in eight of nine animals and no evidence for establishment of transplanted bladder lesions.  (+info)

Superimposed histologic and genetic mapping of chromosome 9 in progression of human urinary bladder neoplasia: implications for a genetic model of multistep urothelial carcinogenesis and early detection of urinary bladder cancer. (3/4713)

The evolution of alterations on chromosome 9, including the putative tumor suppressor genes mapped to the 9p21-22 region (the MTS genes), was studied in relation to the progression of human urinary bladder neoplasia by using whole organ superimposed histologic and genetic mapping in cystectomy specimens and was verified in urinary bladder tumors of various pathogenetic subsets with longterm follow-up. The applicability of chromosome 9 allelic losses as non-invasive markers of urothelial neoplasia was tested on voided urine and/or bladder washings of patients with urinary bladder cancer. Although sequential multiple hits in the MTS locus were documented in the development of intraurothelial precursor lesions, the MTS genes do not seem to represent a major target for p21-23 deletions in bladder cancer. Two additional tumor suppressor genes involved in bladder neoplasia located distally and proximally to the MTS locus within p22-23 and p11-13 regions respectively were identified. Several distinct putative tumor suppressor gene loci within the q12-13, q21-22, and q34 regions were identified on the q arm. In particular, the pericentromeric q12-13 area may contain the critical tumor suppressor gene or genes for the development of early urothelial neoplasia. Allelic losses of chromosome 9 were associated with expansion of the abnormal urothelial clone which frequently involved large areas of urinary bladder mucosa. These losses could be found in a high proportion of urothelial tumors and in voided urine or bladder washing samples of nearly all patients with urinary bladder carcinoma.  (+info)

Level of retinoblastoma protein expression correlates with p16 (MTS-1/INK4A/CDKN2) status in bladder cancer. (4/4713)

Recent studies have shown that patients whose bladder cancer exhibit overexpression of RB protein as measured by immunohistochemical analysis do equally poorly as those with loss of RB function. We hypothesized that loss of p16 protein function could be related to RB overexpression, since p16 can induce transcriptional downregulation of RB and its loss may lead to aberrant RB regulation. Conversely, loss of RB function has been associated with high p16 protein expression in several other tumor types. In the present study RB negative bladder tumors also exhibited strong nuclear p16 staining while each tumor with strong, homogeneous RB nuclear staining were p16 negative, supporting our hypothesis. To expand on these immunohistochemical studies additional cases were selected in which the status of the p16 encoding gene had been determined at the molecular level. Absent p16 and high RB protein expression was found in the tumors having loss of heterozygosity within 9p21 and a structural change (mutation or deletion) of the remaining p16 encoding gene allele, confirming the staining results. These results strongly support the hypothesis that the RB nuclear overexpression recently associated with poor prognosis in bladder cancer is also associated with loss of p16 function and implies that loss of p16 function could be equally deleterious as RB loss in bladder and likely other cancers.  (+info)

Differential regulation of p21waf-1/cip-1 and Mdm2 by etoposide: etoposide inhibits the p53-Mdm2 autoregulatory feedback loop. (5/4713)

The Mdm2 protein is frequently overexpressed in human non-seminomatous germ cell tumours and transitional carcinoma of the bladder where it may contribute to tolerance of wtp53. Mdm2 forms an autoregulatory feedback loop with p53; the Mdm2 gene is responsive to transactivation by p53 and once synthesized the Mdm2 protein terminates the p53 response. We show here that the topoisomerase poison etoposide, like ultra violet irradiation, inhibits Mdm2 synthesis. Cytotoxic concentrations of etoposide (IC90 for > 3 h) result in inhibition of Mdm2 induction at both the RNA and protein level. Rapid apoptosis ensues. Global transcription is not inhibited: p21waf-1/cip1 and GADD45 expression increase in a dose dependent manner. Inhibition of Mdm2 synthesis depends on the continuous presence of etoposide, suggesting the DNA damage may prevent transcription. Downregulation of Mdm2 transcript occurs in cells expressing HPV16-E6 suggesting that inhibition of Mdm2 transcription is p53-independent. When cells are -treated with a pulse (1 h) of etoposide and reincubated in drug free medium, Mdm2 synthesis commences immediately after damage is repaired (3 h) and the p53 response is attenuated. Induction of apoptosis and loss of clonogenicity are 3-5-fold lower under pulse treatment conditions. This is the first observation of inhibition of Mdm2 transcription following treatment with topoisomerase (topo II) poisons, a feature that may be useful in tumour types where p53 is tolerated by overexpression of Mdm2.  (+info)

Tumor-induced interleukin-10 inhibits type 1 immune responses directed at a tumor antigen as well as a non-tumor antigen present at the tumor site. (6/4713)

Interleukin (IL)-10 is a potent immunosuppressive cytokine that has been found to be present at the tumor site in a wide variety of human cancers, including transitional cell carcinoma of the bladder. Using a murine bladder tumor (MB49), which we show to express the male transplantation antigen (HY), we tested the hypothesis that IL-10 at the tumor site can block the generation of a tumor-specific type 1 immune response. We show that, despite its expression of HY, MB49 fails to prime for an HY-specific type 1 (IFN-gamma) response in normal female mice. Although MB49 does not constitutively produce IL-10, our data support a model whereby MB49 induces infiltrating cells to produce IL-10. This feature rendered the IL-10 knockout (KO) mouse, whose infiltrating cells are incapable of IL-10 production, a suitable model in which to study MB49 in the absence of IL-10. When injected into IL-10 KO mice, MB49 does prime for an HY-specific, type 1 immune response. Furthermore, IL-10 KO mice show prolonged survival and an increased capacity to reject tumors as compared with normal mice. We also tested the ability of tumor-induced IL-10 to inhibit immunization to a non-tumor antigen present at the tumor site. When vaccinia virus encoding beta-galactosidase (beta-gal) is injected into the tumors of normal mice, no beta-gal-specific IFN-gamma response is mounted. However, when this same viral construct is injected into the tumors of IL-10 KO mice, it produces a strong beta-gal-specific, IFN-gamma response. These studies demonstrate that tumor-induced IL-10 can block the generation of a tumor-specific type 1 immune response as well as subvert attempts to elicit a type 1 immune response to a non-tumor antigen at the tumor site.  (+info)

Anti-epidermal growth factor receptor antibody C225 inhibits angiogenesis in human transitional cell carcinoma growing orthotopically in nude mice. (7/4713)

Epidermal growth factor receptor (EGFR) regulates the growth and progression of human transitional cell carcinoma (TCC) of the bladder. We have shown that therapy targeting EGFR inhibited the growth of human TCC established orthotopically in nude mice. The purpose of this study was to evaluate whether EGFR-directed therapy affects angiogenesis associated with the growth and metastasis of human TCC. We determined the cytostatic effect and the effect on production of angiogenic factors after in vitro treatment of the human TCC cell line 253J B-V with MAb C225, a chimerized monoclonal anti-EGFR antibody. The 253J B-V cells were implanted orthotopically into athymic nude mice, and established tumors (4 weeks) were treated with i.p. MAb C225. Expression of the angiogenic factors vascular endothelial growth factor (VEGF), interleukin-8 (IL-8), and basic fibroblast growth factor (bFGF) was evaluated by immunohistochemistry and in situ mRNA hybridization analyses and correlated with microvessel density evaluated after immunohistochemical staining with anti-CD31. In vitro treatment with MAb C225 inhibited mRNA and protein production of VEGF, IL-8, and bFGF by 253J B-V cells in a dose-dependent manner. MAb C225 therapy of nude mice with established TCCs growing orthotopically resulted in inhibition of growth and metastasis compared with controls (P <0.0005). VEGF, IL-8, and bFGF expression was significantly lower in treated tumors than in controls. The down-regulation of these angiogenic factors preceded the involution of blood vessels. These studies indicate that therapy with anti-EGFR MAb C225 has a significant antitumor effect mediated, in part, by inhibition of angiogenesis.  (+info)

Vaginal epithelioid angiosarcoma. (8/4713)

A case of epithelioid angiosarcoma of the vagina is described. Only five cases of angiosarcoma at this site have been reported, three of which followed radiotherapy for other gynaecological malignancies. None is described as an epithelioid angiosarcoma, an unusual and recently described variant which is readily confused with carcinoma. This is thought to be the first reported epithelioid angiosarcoma at this site and highlights the difficulties in diagnosis.  (+info)