Identity of tumorigenic human urothelial cell lines and 'spontaneously' transformed sublines.

Restriction fragment length polymorphism (RFLP) analysis, comparative marker chromosome analysis, and polymorphic enzyme analysis was carried out on a total of eight human urothelial cell lines and sublines selected according to our knowledge of their HLA-A,B phenotype. RFLP analysis and cytogenetic analysis showed that the cell lines Hu1703He, Hu1922, and T24 are genuine cell lines of different origin. The identity of Hu1703He could not be confirmed by its isozyme phenotype which was identical to the T24 phenotype. RFLP analysis and isozyme analysis revealed that three cell lines, Hu456, Hu549, and Hu961a, and two transformed sublines, HCV-29Tmv and Hu609Tmv, are sublines of T24. A common origin of Hu456, Hu549, Hu961a, HCV-29Tmv, and Hu609Tmv was confirmed by marker chromosome analysis. However, the T24 origin of these cytogenetically related cell lines was not supported by chromosome analysis of T24. RFLP analysis and HLA phenotyping of two tumorigenic and invasive sublines isolated from a culture of non-tumorigenic Hu609 cells showed that non-tumorigenic Hu609 cells can transform ''spontaneously'' in vitro into tumorigenic Hu609T cells. The results emphasise the need for careful monitoring and screening of cell lines for their identity using more than one identification parameter.     

Expression of polymorphic HLA-A,B epitopes in human urothelial cell lines.

Malignant human urothelial cell lines propagated in vitro have previously been demonstrated to express low amounts of monomorphic HLA-A,B,C as compared to premalignant urothelial cells. In this study the expression of polymorphic HLA-A,B epitopes in human urothelial cell lines have been investigated in greater detail. The expression of HLA-B locus coded epitopes in malignant TGrIII cells was demonstrated to be low or absent as compared to pre-malignant TGrII or slightly transformed TGrI cells, suggesting a mechanism by which malignant cells could escape from the host immune response. The extreme polymorphism of HLA-A,B,C antigens suggests that HLA typing could be used as a method to identify the origin of cell lines which is essential in the study of the process of malignant transformation in vitro, or when correlating in vitro data with clinical observations of the patient. Two urothelial cell lines classified as slightly transformed (TGrI) and two as pre-malignant (TGrII) could, according to their expression of polymorphic HLA-A,B epitopes, be identified as genuine independent cell lines. One TGrII cell line previously designated Hu1734 shared the same HLA-A,B phenotype as the genuine HCV29 (TGrII) cell line and is therefore suspected to be a subline of the latter. Out of 18 cell lines and sublines classified as TGrIII the fidelity of four (Hu1922 and three sublines of T24) was proved by their HLA-A,B phenotype. Mistaken identity either by contamination or false labelling of the cultures was suspected in samples of six TGrIII cell lines and sublines. In four of these the HLA-A,B type characteristic for the T24 cell line could be demonstrated, but in general HLA typing of TGrIII cell lines as a method to identify the origin of the individual cell lines failed, primarily due to the decreased expression of HLA-A,B,C antigens and the apparent selective loss of HLA-B locus coded antigens.     

Gangliosides in human urothelial cell lines of different transformed phenotypes: the effect of v-raf-oncogene transfection

In a previous study we have shown that established human urothelial cell lines, representing grade of transformation II (TGr II, non-tumorigenic, non-invasive cells), are characterized by accumulation of the GM2 ganglioside as compared to cell lines of TGr III with tumorigenic and invasive properties. In the present study, the analysis of gangliosides from two tumorigenic sublines obtained after transfection of the TGr II cell line HCV 29 with the v-raf-oncogene, provided further evidence for the inverse relationship between tumorigenicity and the GM2 ganglioside expression. The two transfected sublines: T112C1 and T112D1, representing TGr III, were characterized by a decreased level of GM2 which was accompanied by an increased content of the GM3 ganglioside as compared to the parental HCV 29 cell line.     

Characterization of mouse urothelial cell lines in different phases of transitional-cell carcinogenesis

Altered cellular responsiveness to growth factors is one of the factors involved in carcinogenesis. In order to study the role of growth factors in transitional-cell carcinogenesis, we established 3 urothelial cell lines from normal mouse urothelium, designated g/G, NUC-5 and NUC-I. These cell lines were studied by light and transmission electron microscopy, karyotyp-ing, grafting in syngeneic mice, growth-factor response in vitro under serum-free conditions, and EGF receptor expression. In the presence of insulin or insulin-like growth factors I and II, proliferation of the non-tumorigenic DNA-tetraploid g/G and DNA aneuploid NUC-5 cells is stimulated by EGF, TGFα, bFGF and aFGF. This stimulation can be abolished in g/G but not in NUC-5 cells by simultaneous addition of TGFβ. Proliferation of g/G and NUC-5 cells can also be stimulated by PDGF-AA. The spindle-cell-like NUC-I cells are DNA aneuploid and tumori-genic in syngeneic mice; they express low levels of EGF receptors and their autonomous proliferation is only affected by insulin or insulin-like growth factors. Each of these cell lines seems to reflect a different phase in transitional-cell carcinogenesis: g/G cells have gained immortality, have become tetraploid, but are non-tumorigenic and growth-factor-dependent. NUC-5 cells have become aneuploid, have a growth-factor responsiveness different from that of normal epithelial cells, but are still non-tumorigenic. NUC-1 cells are aneuploid, tumorigenic, and growth-factor-independent. These urothelial cell lines provide a suitable tool for further studies in transitional-cell carcinogenesis.     

Cell surface proteins and glycoproteins from biologically different human colon carcinoma cell lines

Six cultured human colon cancer cell lines possessing different biological characteristics were enzymatically radiolabeled in situ with 125I and 3H, and the labeled cell surface proteins and glycoproteins were compared. The electrophoretic patterns of labeled cell surface material suggest correlations between biological properties and cell surface proteins. Highly aggressive cell lines (as assessed by in vitro parameters) had predominant peaks of 125I-labeled proteins between molecular weights 66,000 and 92,500. The major peak of radioiodinated material from the more indolent cell lines occurred between molecular weights 31,000 and 45,000. The profile of one 125I-labeled intermediately aggressive cell line was similar to the profiles of the more aggressive lines, whereas another intermediate line exhibited a profile different from those of both indolent and aggressive lines. Electrophoresis of tritiated material indicated that essentially all of the recovered labeled glycoprotein was of relatively high molecular weight (92,000-180,000) in the indolent lines, whereas the intermediate and highly aggressive lines had patterns with significant peaks between molecular weights 45,000 and 92,500.     

In vitro transformation of cell lines from human salivary gland tumors.

Explanted cells from salivary gland tumors are particularly difficult to propagate in vitro and not efficiently immortalized by agents such as simian virus 40. Human papillomavirus 16 (HPV16) has been widely used to transform cells of epithelial origin, but its use for salivary gland cell transformation has not been described. In this study, we employed viral constructs containing the E6/E7 genes of HPV16 to infect and stably transform 9 salivary gland tumor cell cultures. Four of the tumor cell cultures were derived from benign tumors and 5 from malignant tumors. All of the original cell cultures were diploid; however, 6 contained subpopulations of cells with structural abnormalities. All 9 cell cultures were successfully transformed, and 8 were immortalized. The resulting cell lines have decreased serum requirements, exhibit a high proliferation rate, are E6/E7-positive and form colonies in soft agar. Immuno-histochemical and molecular studies confirmed that the transformed cells were indeed epithelial/myoepithelial in origin. All of the transformed cell lines had a diploid or near-diploid karyotype, and 2 contained the original translocated chromosomes in all cells. Our report represents a new application of the E6/E7 system in immortalizing salivary gland cell cultures, resulting in retention of the cellular features found in the native tissue without a general destabilization of the karyotype. These types of tissue culture resources should prove useful for positional cloning and functional studies of genes involved in salivary gland oncogenesis.     

Tissue culture model of transitional cell carcinoma: characterization of twenty-two human urothelial cell lines

Twenty-two continuous cell lines derived from normal and neoplastic urothelium, maintained under identical culture conditions, were characterized in terms of isozyme phenotype, tumorigenicity, and xenograft morphology following xenotransplantation to nude mice, cytological appearance, in vitro growth rate, labelling index, and colony-forming efficiency, in parallel with separate studies of in vitro drug sensitivities and monoclonal antibody reactivities. Three groups were identified: (a) distinct lines with differing isozyme patterns, a broad spectrum of growth characteristics, and xenograft morphologies similar to the histopathology of the parent tumors after periods of up to 17 yr following establishment in vitro; (b) cross-contaminated sublines (maintained separately in different laboratories for periods of up to 10 yr), with identical isozyme patterns and similar growth characteristics, but differing markedly in tumorigenicity and xenograft morphology; and (c) lines derived from normal urothelium which were nontumorigenic and had an isozyme pattern usually only encountered in untransformed cells. These data indicate that cell lines representative of human transitional cell carcinomas can be selected on the basis of xenograft morphology and isozyme patterns, and that a panel of lines derived from normal and neoplastic urothelium could provide a model system to study the biology and treatment of this disease.     

Extracellular matrix proteins characterize human tumor cell lines

Extracellular matrix proteins synthesized and secreted by adherent human tumor cell lines were analyzed using metabolic labelling with glycine and proline in the presence of ascorbate, polypeptide analysis and polyacrylamide gel electrophoresis, affinity chromatography, collagenase digestion, and immunofluorescence staining. The results showed a characteristic pattern of matrix proteins for each tumor cell type. Tumor cell lines of mesenchymal origin produced mostly interstitial types (I and II) of collagen and fibronectin. Carcinoma cell lines secreted only basement membrane proteins, type IV collagen, laminin and fibronectin, but not interstitial collagen. A melanoma and a rhabdomyosarcoma cell line produced type V of procollagen that has not previously been described in cell culture. Neuroblastoma cells were shown to be phenotypically heterogeneous also with respect to matrix protein production. We propose that the analysis of extracellular matrix proteins may serve as an adjunct in the classification of human tumors.     

Biological evaluation on different human cancer cell lines of novel colchicine analogs.

Three new 7-0-substituted deacetamidothiocolchicine derivatives have been evaluated for their antitumor activity against various human tumor cell lines, some of which express the multidrug resistance (MDR) phenotype, for their impact on the cell cycle and their binding to tubulin. Colchicine and thiocolchicine were used as reference compounds. Thiocolchicine was the most active agent on MDR-negative cells in terms of growth inhibition, whereas for multidrug-resistant cells, thiocolchicone was the most active compound (IC50 = 14 nM). As indicated by statistical analysis, a perfect agreement for the potency order (IC50 values) of the compounds between all the MDR-negative cancer cells (k = 1.00), a poor agreement between MDR-positive and MDR-negative cancer lines, and a moderate agreement (k = 0.50) between the two resistant cancer cells MCF-7 ADRr and CEM VBL were observed. To gain further insight into the mechanism of the antitumor activity of colchicinoids, the most active compounds, colchicone and thiocolchicone, were selected to evaluate their effect on cell cycle, apoptosis, and tubulin interaction. The highest recruitment activity into the G21/M phase of the cell cycle was detected in thiocolchicone-treated breast cancer cells. Interestingly, after 72 h of culture, when the cell cycle block subsided, a consistent amount of DNA fragmentation, a hallmark of apoptosis, was evident. Morphological analysis of MCF-7 ADRr cells confirmed this hypothesis and revealed that thiocolchicone was able to induce apoptosis in this MDR-bearing model. We also demonstrated, using flow cytometry, that thiocolchicone interacts with alpha- and beta-tubulin, thereby affecting the expression of both subunits.     

Chromosomal characterization and isoenzyme pattern of non-malignant and malignant human urothelial cell lines

The karyotypes and selected isoenzymes of five cell lines, HU 961b, HU 1922, HU 609, HCV-29 and HU 1703 He, were characterized. These cell lines were derived either from histologically normal human urothelial cells or from transitional cell carcinoma (TCC) of the urinary bladder. They displayed different life span in vitro and transplantability in nude mice, as well as a unique isoenzyme and chromosomal pattern. In addition, various chromosomes were involved in the formation of marker chromosomes in these cell lines. Since there was a lack of consistency in chromosomal changes in the cell lines with TCC origin, the cause of malignancy could not be attributed to the abnormality of specific chromosomes.     

Expression of stem cell markers in human astrocytomas of different WHO grades

According to new hypotheses astrocytomas/gliomas either arise from or attract neural stem cells. Biological markers, particularly antigenic markers, have played a significant role for the characterization of these tumour stem cells (TSCc). Because these studies have been performed with single experimental samples mostly from gliomas, we investigated the expression of the stem cell markers CD133/Prominin, Nestin, Sox-2, Musashi-1, CXCR4, Flt-4/VEGFR-3 and CD105/Endoglin in 72 astrocytomas of different WHO-grades and compared it to normal adult human brain. Expression of their mRNA was quantified by quantitative RT-PCR, of their protein by counting immunopositive cells. In contrast to normal brain, tumour samples showed a high variability for the expression of all markers. However, their mean expression was significantly increased in astrocytomas, but this depended on the WHO grade only for CD133, Nestin, Sox-2 and Musashi-1. Confocal microscopy revealed that these markers mostly could be co-stained with glial fibrillary acidic protein, a marker for astoglial cells, but less frequently with the proliferation marker Ki-67/MIB-1. These markers sometimes, but not necessarily could be co-stained with each other in complex patterns. Our results show that most astrocytomas contain considerable portions of cells expressing stem cell markers. It appears that some of these cells originate from tumour genesis (supporting the stem cell hypothesis) while others are attracted by the tumours. Further functional markers are required to differentiate these TSC-types.     

The sialosyl Lewis a ganglioside is present in tumorigenic human urothelial cell lines

The sialosyl Lewis a antigen was identified in a ganglioside extract from a malignant human urothelial cell line (Hu 1703He) by fast atom bombardment mass spectrometry. The presence of this antigen in urothelial cell lines with varying tumorigenic properties was further studied using the 19-9 monoclonal antibody (MAb). The sialosyl Lewis a ganglioside was expressed only in the tumorigenic cell lines. Thus, the expression of this antigen is a marker of malignancy for human urothelial cell lines. Mass spectrometry also suggests that the fucosyl GM1 ganglioside was expressed in the Hu 1703He cell line. This was confirmed using the F12 MAb, specific for fucosyl GM1. However, the expression of this antigen was not confined to cell lines with tumorigenic properties.     

Ia-like antigen expression on biologically different human melanoma cell lines

Ia-like antigen binding of a large panel of monoclonal antibodies (six anti-human Ia-like monoclonal antibodies and ten murine anti-Ia monoclonal antibodies cross-reactive with human Ia-like antigens) were compared on seven permanent human melanoma cell lines by radioimmunoassay. Cell lines were initiated from primary or metastatic tumors and presented various levels of tumorigenicity (assessed by heterotransplantation in nude mice) and pigmentation (shown by 5-S-cysteinyldopa determination and cytological data). Two cell lines originated from the same primary melanoma, while two other pairs of cell lines originated from superficial spreading melanoma or metastatic lymph node of the same patients. Identical Ia-like allodeterminants were found in cell lines of the same individual origin. Quantitative expression of β₂-microglobulin and Ia-like antigens was similar in all cell lines except for one, in which these molecules were expressed in lower amounts. These results indicate that Ia-like antigen expression of the cell lines is unrelated to primary or metastatic origin, degree of pigmentation and ability to grow in nude mice.     

Binding activities of cis-platin-damage-recognition proteins in human tumour cell lines

Proteins can be detected by South-western analyses of human tumour-cell extracts binding to double-stranded oligonucleotide DNA treated in vitro with the chemotherapeutic drug cis-diamminedichloroplatinum (11) (CDDP), but not to untreated DNA. The relative molecular masses of proteins binding to the CDDP-treated double-stranded oligonucleotide are 25, 48 and 97 kDa. The binding activity of 2 of the CDDP-damage-recognition proteins, of relative molecular mass 48 and 97 kDa, is greater in a CDDP-resistant human ovarian tumour cell line than in the parental sensitive line. South-western analysis of panel of human bladder cell lines and CDDP-sensitive testicular cell lines show consistent patterns of CDDP-damage-recognition proteins within each cell type, however with differences between the 2 cell types. Binding of the proteins to CDDP-damaged DNA and the altered binding activity detected in tumour cell lines suggests that alteration in damage-recognition proteins could play a role in tumour response to CDDP.     

Two-dimensional polyacrylamide gel analysis on nuclear proteins from human tumor cell lines

Two-dimensional polyacrylamide gel electrophoretic analysis was carried out on HeLa, KB, ALL and GW-39 cell "Chromatin Fraction II" proteins. Of the many proteins found, most were visualized in earlier studies on rodent tumors and normal tissues. Of these the greater density of protein CP and the presence of protein CG' differentiates tumors from the nontumor tissues. In samples of normal and mitogen stimulated human lymphocytes, protein CG' was absent and protein CP was present in small amounts. Two-dimensional patterns of 0.4N H2SO4 soluble nuclear proteins showed elevated amounts of proteins C16-18 in the GS-39 cell patterns. Proteins Hu1, G1, G2, G3 and G5 were detected only in human cell nuclei. The increased density of staining for protein CP and the presence of CG' are potential biological markers for neoplastic cells.     

The Thomsen-Friedenreich antigen on human urothelial cell lines detectable by peanut lectin and monoclonal antibody raised against human glycophorin A

The Thomsen-Friedenreich (TF) antigen is a cryptic disaccharide structure on human erythrocytes which can be exposed by neuraminidase treatment and which is supposed to be expressed in an unmasked form on some carcinoma cells. For its detection in addition to auto-, allo- and heteroantisera, PNA (peanut lectin) is being applied. In the present studies the mouse monoclonal antibody (MoAb) raised to asialoglycophorin from human erythrocytes was used. The MoAb 22.19 is of mouse IgM isotype and is specifically binding to beta-D Gal-1-3 alpha-D GalNAc. The human urothelial cell lines maintained and characterized earlier were analyzed using indirect immunofluorescence assays. Among the spectrum of cell lines tested, five out of six cell lines belonging to the transformation grade III category (invasive in vitro and tumorigenic in nude mice) expressed TF antigen. The relationship between expression of TF antigen and other earlier defined biological traits related to malignant phenotype is discussed.     

Gap junction expression following UVC-induced neoplastic transformation in human hybrid cell lines

Decreased connexin gene expression and loss of the capacity for either homologous or heterologous intercellular communication has been associated with neoplastic transformation. We tested the hypothesis that loss of gap junctional intercellular communication (GJIC) correlates with tumorigenic potential in the HeLa x skin fibroblast human hybrid cell system. Connexin gene expression, gap junction function and tumorigenicity were determined for the non-tumorigenic somatic hybrid cell line (CGL1) and a series of UVC-induced tumorigenic cell lines derived from CGL1. CGL1 and the parental skin fibroblasts express connexin43 (alpha1 gap junction gene) mRNA and protein, form gap junctional plaques and have functional gap junctions. UVC- irradiation of CGL1 cells produced a cell line (UV12) with an aggressive tumorigenic phenotype, which lost connexin43 expression as well as both homologous and heterologous GJIC and was in this respect similar to HeLa cells. However, the phenotype of UV12 cells exhibited some instability and revertants to a less aggressive tumorigenic phenotype were isolated. These cells expressed connexin43 mRNA and protein, and demonstrated homologous GJIC. Furthermore, cells reconstituted from a tumor derived from this revertant cell line retained significant connexin43 expression and homologous GJIC, although they exhibited an aggressive tumorigenic phenotype. Thus, functional homologous GJIC cannot be dissociated from tumorigenicity in this system. However, heterologous GJIC between these same UVC-induced tumorigenic cell lines and normal human skin fibroblasts was reduced, whereas the non-tumorigenic hybrid cells showed extensive heterologous GJIC. In summary, re-acquisition of connexin43 expression and homologous GJIC does not restore the non-tumorigenic phenotype in UVC- induced tumorigenic HeLa skin fibroblast human hybrid cells. However, reduction of heterologous GJIC does correlate with tumorigenicity in this cell system.