Tumorigenicity of T24 urinary bladder carcinoma cell sublines

The evolution of single cell-derived colorectal cancer cell lines is dominated by the continued selection of tumor-specific genomic imbalances, despite random chromosomal instability

Intratumor heterogeneity is a major challenge in cancer treatment. To decipher patterns of chromosomal heterogeneity, we analyzed six colorectal cancer cell lines by multiplex interphase FISH (miFISH). The mismatch-repair-deficient cell lines DLD-1 and HCT116 had the most stable copy numbers, whereas aneuploid cell lines (HT-29, SW480, SW620 and H508) displayed a higher degree of instability. We subsequently assessed the clonal evolution of single cells in two colorectal carcinoma cell lines, SW480 and HT-29, which both have aneuploid karyotypes but different degrees of chromosomal instability. The clonal compositions of the single cell-derived daughter lines, as assessed by miFISH, differed for HT-29 and SW480. Daughters of HT-29 were stable, clonal, with little heterogeneity. Daughters of SW480 were more heterogeneous, with the single cell-derived daughter lines separating into two distinct populations with different ploidy (hyper-diploid and near-triploid), morphology, gene expression and tumorigenicity. To better understand the evolutionary trajectory for the two SW480 populations, we constructed phylogenetic trees which showed ongoing instability in the daughter lines. When analyzing the evolutionary development over time, most single cell-derived daughter lines maintained their major clonal pattern, with the exception of one daughter line that showed a switch involving a loss of APC. Our meticulous analysis of the clonal evolution and composition of these colorectal cancer models shows that all chromosomes are subject to segregation errors, however, specific net genomic imbalances are maintained. Karyotype evolution is driven by the necessity to arrive at and maintain a specific plateau of chromosomal copy numbers as the drivers of carcinogenesis.

Autonomic Receptor-mediated Regulation of Production and Release of Nitric Oxide in Normal and Malignant Human Urothelial Cells

In the urinary bladder, the main source of NO seems to be the urothelium and the underlying suburothelium. In this study, we aimed to characterize how receptors in the human urothelium regulate the production and release of NO. For this, we cultured two human urothelial cell lines - the normal immortalized cell line UROtsa and the malignant cell line T24. These were treated with an array of agonists and antagonists with affinity for adrenergic, muscarinic and purinergic receptors. The production of NO and expression of nitric oxide synthase (NOS) was studied by immunocytochemistry and Western blotting. The amount of released NO was measured indirectly by detecting nitrite using amperometry and a Griess reaction kit. The results showed that NO, endothelial NOS and inducible NOS were predominantly produced and expressed in the close vicinity of the nucleus in untreated human urothelial cells. Upon treatment with a beta-adrenoceptor agonist, but not any of the other agonists or antagonists, the pattern of NO production changed, showing a more even production throughout the cytosol. The pattern of expression of endothelial NOS changed in a similar way upon dobutamine treatment. The release of nitrite, as a measurement of NO, increased after treatment with dobutamine from 0.31 ± 0.029 to 1.97 ± 0.18 nmol and 0.80 ± 0.12 to 3.27 ± 0.24 nmol in UROtsa and T24, respectively. In conclusion, our results show that the expression of NOS and production of NO as well as the release of NO from human urothelial cells is regulated by beta-adrenoceptor activation.

Upregulated MT1-MMP/TIMP-2 axis in the TSU-Pr1-B1/B2 model of metastatic progression in transitional cell carcinoma of the bladder

Muscle invasive transitional cell carcinoma (TCC) of the bladder is associated with a high frequency of metastasis, resulting in poor prognosis for patients presenting with this disease. Models that capture and demonstrate step-wise enhancement of elements of the human metastatic cascade on a similar genetic background are useful research tools. We have utilized the transitional cell carcinoma cell line TSU-Pr1 to develop an in vivo experimental model of bladder TCC metastasis. TSU-Pr1 cells were inoculated into the left cardiac ventricle of SCID mice and the development of bone metastases was monitored using high resolution X-ray. Tumor tissue from a single bone lesion was excised and cultured in vitro to generate the TSU-Pr1-B1 subline. This cycle was repeated with the TSU-Pr1-B1 cells to generate the successive subline TSU-Pr1-B2. DNA profiling and karyotype analysis confirmed the genetic relationship of these three cell lines. In vitro, the growth rate of these cell lines was not significantly different. However, following intracardiac inoculation TSU-Pr1, TSU-Pr1-B1 and TSU-Pr1-B2 exhibited increasing metastatic potential with a concomitant decrease in time to the onset of radiologically detectable metastatic bone lesions. Significant elevations in the levels of mRNA expression of the matrix metalloproteases (MMPs) membrane type 1-MMP (MT1-MMP), MT2-MMP and MMP-9, and their inhibitor, tissue inhibitor of metalloprotease-2 (TIMP-2), across the progressively metastatic cell lines, were detected by quantitative PCR. Given the role of MT1-MMP and TIMP-2 in MMP-2 activation, and the upregulation of MMP-9, these data suggest an important role for matrix remodeling, particularly basement membrane, in this progression. The TSU-Pr1-B1/B2 model holds promise for further identification of important molecules.

Distinct transduction mechanisms of cyclooxygenase 2 gene activation in tumour cells after photodynamic therapy

Photodynamic therapy (PDT) is a minimally invasive treatment for cancer and several noncancerous proliferating cell diseases. PDT relies on the uptake of a photosensitizing compound by the pathologic tissue followed by a selective irradiation with visible light, which leads to oxidative stress-mediated cell death. However, some studies showed that PDT induces the release of proangiogenic factors, such as vascular endothelial growth factor, and/or cyclooxygenase-2 (COX-2), thereby promoting cancer cell regrowth following PDT. In this work, we focused on the molecular mechanisms regulating COX-2 expression after low-dose PDT in two cancer cell lines, namely HeLa and T24. We report that PDT induces COX-2 expression in these cells and this expression is mainly due to nuclear factor kappa B (NF-kappaB)-dependent transcription of cox-2 gene without any post-transcriptional regulation. However, the transduction mechanism leading to NF-kappaB activation and subsequent cox-2 gene transcription differs in both cell types. In T24, NF-kappaB activation occurs through a protein kinase C (PKC)alpha- and phosphoinositide-3-kinase (PI3K)-dependent I kappa B kinase (IKK) complex activation, whereas in HeLa cells, NF-kappaB activation is mediated by PKC- and PI3K-independent IKK complex activation.

Phenotypic characterization of human umbilical vein endothelial (ECV304) and urinary carcinoma (T24) cells: endothelial versus epithelial features

ECV304 cells reported as originating from human umbilical vein endothelial cells by spontaneous transformation have been used as a model cell line for endothelia over the last decade. Recently, deoxyribonucleic acid fingerprinting revealed an identical genotype for ECV304 and T24 cells (urinary bladder carcinoma cell line). In order to resolve the apparent discrepancy between the identical genotype and the fact that ECV304 cells phenotypically show important endothelial characteristics, a comparative study was performed. Immortalized porcine brain microvascular endothelial cells/C1-2, and Madin Darby canine kidney cells were included as typical endothelial and epithelial cells, respectively. Various methods, such as confocal laser scanning microscopy. Western blot, and protein activity tests, were used to study the cell lines. ECV304 and T24 cells differ in criteria, such as growth behavior, cytoarchitecture, tight junction arrangement. transmembrane electrical resistance, and activity of gamma-glutamyltransferase. Several endothelial markers (von Willebrand factor, uptake of low-density lipoprotein, vimentin) could clearly be identified in ECV304, but not in T24 cells. Desmoglein and cytokeratin, both known as epithelial markers, were found in ECV304 as well as in T24 tells. However, differences were found for the two cell lines with respect to the type of cytokeratin: in ECV304 cells mainly cytokeratin 18 (45 kDa) is found, whereas in T24 cells cytokeratin 8 (52 kDa) is predominant. As we could demonstrate, the ECV304 cell line exposes many endothelial features which, in view of the scarcity of suitable endothelial cell lines, still make it an attractive in vitro model for endothelia.

Size distribution of the urokinase mRNA decay intermediates in different tissues and cell lines

Many genes, particularly those encoding the products participating in the regulation of transcription, replication and tissue remodeling, produce short-lived mRNA. It has been commonly accepted that once mRNA is disintegrated, the degradation process is so rapid that the decay intermediates cannot be detected. In the present study we verified this postulate and focused our attention on the quantification of the decay products of the urokinase-type plasminogen activator (uPA) mRNA that belongs to short-lived mRNAs. Using a previously described modified quantitative RT-PCR method, we have shown that intact uPA mRNA coexists in normal human tissues, Jurkat and 5637 cells with a great abundance of its degradation products. The uPA mRNA decay products were not detected in T24P cells. The content of intact uPA mRNA in normal tissues was as low as 5% of the total amount of its poly(A)(+) fraction. The size distribution of the mRNA decay products suggests that the mRNA is digested by exonucleases or/and non-specific endonuclease with cut sites evenly distributed along the mRNA chain. Different decay degrees were demonstrated for subpopulation of the uPA mRNA molecules with intact 3' and 5' ends.

Genetic and phenotypic changes associated with the acquisition of tumorigenicity in human bladder cancer

There has been a general lack of human paired cell lines that both reproduce the in vivo spectrum of tumor progression of bladder cancer and have some of the genetic changes associated with progression in human tumor tissue. T24, a cell line established from an invasive human transitional cell carcinoma (TCC) of the bladder, has been used extensively in bladder cancer research. However, a significant limitation of this cell line is its lack of tumorigenicity when injected into immunocompromised mice. This characteristic was used to our advantage as we sought to characterize T24T, a highly tumorigenic variant that could then be used to elucidate the genes responsible for human bladder tumor progression. In culture, T24T has a faster doubling time, reaches a higher cell density in monolayer culture, and is more motile than T24 at higher cell densities. T24T is able to form colonies in soft agar, whereas T24 is not, and expresses HRAS, a gene associated with increased aggressiveness in human TCC, at higher levels than T24. Most importantly, T24T forms solid tumors when injected subcutaneously in SCID mice both with and without Matrigel (Sigma, St. Louis, MO), whereas T24 does not. Cytogenetically, the 2 cell lines contain at least 5 shared structural anomalies, as determined by detailed karyotyping. Interestingly, T24T has acquired 4 new structural changes, 3 of which [add(10)(p12), i(10)(q10), -15] have been observed in loss of heterozygosity (LOH) studies of tumor progression in human TCC. It appears that the T24/T24T model may be an excellent tool for the study of human TCC progression because of its relationship with known karyotypic changes associated with human bladder cancer progression. We are currently taking advantage of these paired cell lines to identify genes involved in human TCC progression. Genes Chromosomes Cancer 27:252-263, 2000.

Isolation and characterization of metastatic variants from human transitional cell carcinoma passaged by orthotopic implantation in athymic nude mice

PURPOSE

These studies were designed to develop an orthotopic model for human bladder cancer and to isolate variant metastatic cell lines.

MATERIALS AND METHODS

The human bladder cancer cell line 253J was implanted into the muscular wall of the bladder of athymic nude mice. By in vivo recycling, we selected for 2 variant cell lines: 253J B-V, a bladder line isolated after 5 serial passages in the bladder, and 253J lung-IV, established from a lung tumor nodule that was recycled through the bladder.

RESULTS

These 2 cell lines showed enhanced tumorigenicity, as measured by a decreased latent period, and rapid growth as compared with the parental cell line. Moreover, orthotopic implantation of these cell lines resulted in metastasis to the lungs. These in vivo-selected, metastatic cell lines exhibited unique karyotypic alterations, increased anchorage-independent growth, overexpression of basic fibroblast growth factor, altered expression of adhesion molecules and the ability to migrate through Matrigel.

CONCLUSIONS

This reproducible model of human bladder cancer offers the opportunity to study cellular properties associated with tumor progression and metastasis and is suitable for the evaluation of new therapeutic strategies for invasive bladder cancer.

An in vitro model of intra-epithelial expansion of transformed urothelial cells

Replacement of normal urothelium by pre-cancerous epithelium may explain the high recurrence rate of human bladder cancer. An in vitro model was designed in order to study the mechanisms of expansion of transformed urothelial cells at the expense of normal urothelium. For this purpose, mouse bladder explants were allowed to expand on a transparent porous membrane. Subsequently, cell sheets of the non-tumorigenic mouse urothelial cell line NUC-5, the tumorigenic mouse urothelial cell line NUC-5 Py and the human bladder-carcinoma cell line T24 were inoculated adjacent to the primary explant. Daily measurements of the outgrowth of the bladder explant were performed, and all cultures were terminated on day 24. At this time the post-confluent primary urothelial cell outgrowths still showed proliferative activity, as demonstrated by bromodeoxyuridine incorporation. In due course the non-tumorigenic NUC-5 cells were replaced by the bladder outgrowth. T24 and NUC-5 Py cells were able to inhibit the bladder outgrowth, or even infiltrate or replace the explant. This was confirmed by immunohistochemistry with (species-specific) anti-cytokeratin antibodies and by microscopic evaluation of cross-sections of the porous membrane. This co-cultivation model appears to be suitable for the in vitro study of the mechanisms of intra-epithelial expansion of transformed urothelial cell lines.

Clonal analysis of a bladder cancer cell line: an experimental model of tumour heterogeneity

The continuous cell line UCRU BL 17CL was derived from a human invasive bladder cancer and expresses elements of transitional, squamous and glandular differentiation. Nine clones of this line were established by limit dilution and have been extensively characterised. Only six of these clones grew subcutaneously in nude mice. Of these, three have exhibited local invasion, each in one of five implanted mice. Although all xenografts expressed transitional, squamous and glandular elements, different histological subtypes predominated within each clone. Only clones which grew in nude mice formed colonies in semi-solid medium, and each responded differently to the influence of medium that had been conditioned by the growth of UCRU BL 17CL, suggesting the possible secretion of a growth factor by these cells. The DNA content and lectin binding profiles of the clones also reflected the heterogeneity of the line. UCRU BL 17CL and the nine clones provide a unique model for the study of tumour heterogeneity, progression and differentiation, and the potential autocrine regulation of growth of bladder cancer.

Recombinant human interferon gamma exerts an anti-proliferative effect and modulates the expression of human leukocyte antigens A,B,C and DR in human urothelial cell lines

In this study we have treated three malignant (TGrIII) and two pre-malignant (TGrII) urothelial cell lines with recombinant human interferon gamma (rHu-INF gamma). The malignant cells (HCV29-T112C1, Hu1703He and T24) were inhibited in growth by more than 50% after treatment with 100-1000 units of rHu-INF gamma/ml for 4 days as compared to untreated controls. The growth of the pre-malignant cell lines (HCV29 and Hu609) was not influenced to the same extent in the presence of rHu-INF gamma in the culture medium. Treatment with rHu-INF gamma increased the expression of monomorphic human leukocyte antigens (HLA) A,B,C as well as beta 2-microglobulin in all the cell lines tested, as demonstrated using a quantitative immunofluorescence assay. The tumourigenic cell lines increased their expression of HLA in a dose-dependent way, whereas treatment of the non-tumourigenic cells with higher concentrations of rHu-INF gamma than 10 units/ml, did not increase the HLA-A,B,C expression further. None of the cell lines expressed HLA-DR unless treated with rHu-INF gamma. No correlation between tumourigenicity and the dose of rHu-INF gamma required for "de novo" induction of HLA-DR could be demonstrated. After removal of rHu-INF gamma from the medium, the expression of HLA-DR gradually decreased in less than 14 days, indicating that the expression of HLA-DR is not constitutive but dependent upon the presence of rHu-INF gamma. We conclude that human urothelial cells grown in vitro are sensitive to the anti-proliferative and major-histocompatibility-complex-modulating effects of rHu-INF gamma, and that malignant urothelial cells are more sensitive than pre-malignant cells. Finally, our data indicate a possible role for rHu-INF gamma in the management of human bladder cancer.

Characterization and tumorigenicity of a butyrate-adapted T24 bladder cancer cell line

We have adapted T24P, a tumorigenic subline of the T24 human bladder cancer cell line, to grow in 5 mM butyrate. In the presence of butyrate, the adapted cells (T24P/B) grow more slowly than the unadapted cells (T24P/C), have a lower saturation density, increased serum requirement for growth, loss of ability to form colonies when plated at low cell density, and decreased ouabain sensitivity. Morphologically, T24P/B cells in butyrate are large and flattened with increased cytoplasm. When T24P/B cells are grown without butyrate, the morphological changes, growth rate, plating efficiency, and ouabain sensitivity return to those of T24P/C. While the saturation density increases, it does not return to levels of T24P/C, and the size of colonies never reaches that of the T24P/C colonies. Both T24P/C and T24P/B are tumorigenic in nude mice, however, the T24P/B tumors differ grossly and microscopically from those produced by T24P/C in that they contain large cystic structures filled with clear fluid and lined by transitional cell epithelium with flattened surface layers. Although the transformed phenotype and tumorigenicity of T24P are modified by adaptation to growth in butyrate, no significant changes in ras oncogene RNA or protein expression were identified.

T24 human bladder carcinoma cells with activated Ha-ras protooncogene: nontumorigenic cells susceptible to malignant transformation with carcinogen

A comparative analysis of T24 human bladder carcinoma cells and N-methyl-N'-nitro-N-nitrosoguanidine (MeNNG)-transformed derivatives (MeNNG-T24 cells) revealed the following: (i) The presence of an activated c-Ha-ras gene (in the absence of the normal allele) is insufficient to confer upon T24 cells a tumor-associated phenotype. (ii) MeNNG-transformed T24 cells not only acquire tumor-associated (in vitro) traits (growth in soft agar and rhodamine retention) but, are highly tumorigenic in nude mice. (iii) It is possible to render T24 cells tumorigenic by chemical transformation; therefore, the reason that T24 cells lack tumorigenicity is not because of possible incompatibilities between these cells and nude mice but, in fact, because T24 cells are not malignant. (iv) The loss of expression of a transformation-related Mr 67,000 phosphoprotein by MeNNG-T24 cells after explantation of these cells from nude mouse tumors to in vitro culture indicates that culture conditions can be responsible for rapid phenotypic conversion of human tumor cell lines.