Cellular heterogeneity in a tissue culture cell line derived from a human bladder carcinoma

scATACpipe: A nextflow pipeline for comprehensive and reproducible analyses of single cell ATAC-seq data

Single cell ATAC-seq (scATAC-seq) has become the most widely used method for profiling open chromatin landscape of heterogeneous cell populations at a single-cell resolution. Although numerous software tools and pipelines have been developed, an easy-to-use, scalable, reproducible, and comprehensive pipeline for scATAC-seq data analyses is still lacking. To fill this gap, we developed scATACpipe, a Nextflow pipeline, for performing comprehensive analyses of scATAC-seq data including extensive quality assessment, preprocessing, dimension reduction, clustering, peak calling, differential accessibility inference, integration with scRNA-seq data, transcription factor activity and footprinting analysis, co-accessibility inference, and cell trajectory prediction. scATACpipe enables users to perform the end-to-end analysis of scATAC-seq data with three sub-workflow options for preprocessing that leverage 10x Genomics Cell Ranger ATAC software, the ultra-fast Chromap procedures, and a set of custom scripts implementing current best practices for scATAC-seq data preprocessing. The pipeline extends the R package ArchR for downstream analysis with added support to any eukaryotic species with an annotated reference genome. Importantly, scATACpipe generates an all-in-one HTML report for the entire analysis and outputs cluster-specific BAM, BED, and BigWig files for visualization in a genome browser. scATACpipe eliminates the need for users to chain different tools together and facilitates reproducible and comprehensive analyses of scATAC-seq data from raw reads to various biological insights with minimal changes of configuration settings for different computing environments or species. By applying it to public datasets, we illustrated the utility, flexibility, versatility, and reliability of our pipeline, and demonstrated that our scATACpipe outperforms other workflows.

An In Vitro Barrier Model of the Human Submandibular Salivary Gland Epithelium Based on a Single Cell Clone of Cell Line HTB-41: Establishment and Application for Biomarker Transport Studies

The blood–saliva barrier (BSB) consists of the sum of the epithelial cell layers of the oral mucosa and salivary glands. In vitro models of the BSB are inevitable to investigate and understand the transport of salivary biomarkers from blood to saliva. Up to now, standardized, cell line-based models of the epithelium of the submandibular salivary gland are still missing for this purpose. Therefore, we established epithelial barrier models of the submandibular gland derived from human cell line HTB-41 (A-253). Single clone isolation resulted in five different clones (B2, B4, B9, D3, and F11). Clones were compared to the parental cell line HTB-41 using measurements of the transepithelial electrical resistance (TEER), paracellular marker permeability assays and analysis of marker expression for acinar, ductal, and myoepithelial cells. Two clones (B9, D3) were characterized to be of acinar origin, one clone (F11) to be of myoepithelial origin and one isolation (B4) derived from two cells, to be presumably a mixture of acinar and ductal origin. Clone B2, presumably of ductal origin, showed a significantly higher paracellular barrier compared to other clones and parental HTB-41. The distinct molecular identity of clone B2 was confirmed by immunofluorescent staining, qPCR, and flow cytometry. Experiments with ferritin, a biomarker for iron storage, demonstrated the applicability of the selected model based on clone B2 for transport studies. In conclusion, five different clones originating from the submandibular gland cell line HTB-41 were successfully characterized and established as epithelial barrier models. Studies with the model based on the tightest clone B2 confirmed its suitability for transport studies in biomarker research.

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.

Activation of Piezo1 sensitizes cells to TRAIL-mediated apoptosis through mitochondrial outer membrane permeability

TRAIL specifically induces apoptosis in cancer cells without affecting healthy cells. However, TRAIL’s cancer cytotoxicity was insufficient in clinical trials. Circulatory-shear stress is known to sensitize cancer cells to TRAIL. In this study, we examine the mechanism of this TRAIL sensitization with the goal of translating it to static conditions. GsMTx-4, a Piezo1 inhibitor, was found to reduce shear stress-related TRAIL sensitization, implicating Piezo1 activation as a potential TRAIL-sensitizer. The Piezo1 agonist Yoda1 recreated shear stress-induced TRAIL sensitization under static conditions. A significant increase in apoptosis occurred when PC3, COLO 205, or MDA-MB-231 cells were treated with Yoda1 and TRAIL in combination, but not in Bax-deficient DU145 cells. Calpastatin inhibited apoptosis in Yoda1-TRAIL treated cells, indicating that calpain activation is necessary for apoptosis by Yoda1 and TRAIL. Yoda1 and TRAIL treated PC3 cells showed increased mitochondrial outer membrane permeability (MOMP), mitochondrial depolarization, and activated Bax. This implies that Piezo1 activation sensitizes cancer cells to TRAIL through a calcium influx that activates calpains. The Calpains then induce MOMP by enhancing Bax activation. From these experiments a computational model was developed to simulate apoptosis for cells treated with TRAIL and increased calcium. The computational model elucidated the proapoptotic or antiapoptotic roles of Bax, Bcl-2, XIAP, and other proteins important in the mitochondrial-apoptotic signaling pathway.

Mannose glycosylation is an integral step for NIS localization and function in human breast cancer cells

Chasing an intriguing biological question on the disparity of sodium iodide symporter (NIS, officially known as SLC5A5) expression and function in the clinical scenario of breast cancer, this study addresses key molecular defects involved. NIS in cancer patients has primarily been recorded to be a cytoplasmic protein, thus limiting the scope for targeted radio-iodine therapy. We developed NIS transgene-overexpressing MCF-7 breast cancer cells, and found a few clonal derivatives that show predominant expression of NIS in the plasma membrane. The majority of clones, however, showed cytosolic NIS expression over long passages. Cells expressing membranous NIS show unperturbed dynamic trafficking of NIS through secretory pathway organelles when compared to cells expressing cytoplasmic NIS or to parental cells. Further, treatment of cells expressing membranous NIS with specific glycosylation inhibitors highlighted the importance of inherent glycosylation processing and an 84 gene signature glycosylation RT-Profiler array revealed that clones expressing NIS in their membrane cluster separately compared to the other cells. We further confirm a role of three differentially expressed genes, i.e. MAN1B1, MAN1A1 and MAN2A1, in regulating NIS localization by RNA interference. Thus, this study shows the important role of mannosidase in N-glycosylation processing in order to correctly traffic NIS to the plasma membrane in breast cancer cells.This article has an associated First Person interview with the first author of the paper.

Gene expression, proteome and calcium signaling alterations in immortalized hippocampal astrocytes from an Alzheimer's disease mouse model

Evidence is rapidly growing regarding a role of astroglial cells in the pathogenesis of Alzheimer’s disease (AD), and the hippocampus is one of the important brain regions affected in AD. While primary astroglial cultures, both from wild-type mice and from rodent models of AD, have been useful for studying astrocyte-specific alterations, the limited cell number and short primary culture lifetime have limited the use of primary hippocampal astrocytes. To overcome these limitations, we have now established immortalized astroglial cell lines from the hippocampus of 3xTg-AD and wild-type control mice (3Tg-iAstro and WT-iAstro, respectively). Both 3Tg-iAstro and WT-iAstro maintain an astroglial phenotype and markers (glutamine synthetase, aldehyde dehydrogenase 1 family member L1 and aquaporin-4) but display proliferative potential until at least passage 25. Furthermore, these cell lines maintain the potassium inward rectifying (Kir) current and present transcriptional and proteomic profiles compatible with primary astrocytes. Importantly, differences between the 3Tg-iAstro and WT-iAstro cell lines in terms of calcium signaling and in terms of transcriptional changes can be re-conducted to the changes previously reported in primary astroglial cells. To illustrate the versatility of this model we performed shotgun mass spectrometry proteomic analysis and found that proteins related to RNA binding and ribosome are differentially expressed in 3Tg-iAstro vs WT-iAstro. In summary, we present here immortalized hippocampal astrocytes from WT and 3xTg-AD mice that might be a useful model to speed up research on the role of astrocytes in AD.

Dynamics of CRISPR/Cas9-mediated genomic editing of the AXL locus in hepatocellular carcinoma cells

Genomic editing using the CRISPR/Cas9 technology allows selective interference with gene expression. With this method, a multitude of haploid and diploid cells from different organisms have been employed to successfully generate knockouts of genes coding for proteins or small RNAs. Yet, cancer cells exhibiting an aberrant ploidy are considered to be less accessible to CRISPR/Cas9-mediated genomic editing, as amplifications of the targeted gene locus could hamper its effectiveness. Here we examined the suitability of CRISPR/Cas9 to knockout the receptor tyrosine kinase Axl in the human hepatoma cell lines HLF and SNU449. The genomic editing events were validated in two single cell clones each from putative HLF and SNU449 knockout cells (HLF-Axl^--1, HLF-Axl^--2, SNU449-Axl^--1, SNU449-Axl^--2). Sequence analysis of respective AXL loci revealed one to six editing events in each individual Axl^- clone. The majority of insertions and deletions in the AXL gene at exon 7/8 resulted in a frameshift and thus a premature stop in the coding region. However, one genomic editing event led to an insertion of two amino acids resulting in an altered protein sequence rather than in a frameshift in the AXL locus of the SNU449-Axl^--1 cells. Notably, while no Axl protein expression could be detected by immunoblotting in all four cell clones, both expression of total Axl as well as release of soluble Axl into the supernatant was observed by ELISA in incompletely edited SNU449-Axl^--1 cells. Importantly, a comparative genomic hybridization array revealed comparable genomic changes in Axl knockout cells as well as in cells expressing Cas9 nickase without guide RNAs in SNU449 and HLF cells, indicating vast alterations in genomic DNA triggered by nickase. Together, these data show that the dynamics of CRISPR/Cas9 may cause incomplete editing events in cancer cell lines, as gene copy numbers vary based on genomic heterogeneity.

Photocleavable dimerizer for the rapid reversal of molecular trap antagonists

Herein, we report the development of a photocleavable analog of AP20187, a cell-permeable molecule used to dimerize FK506-binding protein (FKBP) fusion proteins and initiate biological signaling cascades and gene expression or disrupt protein-protein interactions. We demonstrate that this reagent permits the unique ability to rapidly and specifically antagonize a molecular interaction in vitro and follow a biological process due to this acute antagonism (e.g. endosome dispersion) and to release the trap upon photocleavage to follow the cell's return to homeostasis. In addition, this photocleavable AP20187 analog can be used in other systems where the dimerization of FKBP has been used to initiate signaling pathways, offering the ability to correlate the duration of a signaling event and a cellular response.

Impaired Delta Np63 expression associates with reduced beta-catenin and aggressive phenotypes of urothelial neoplasms

p63, a homologue of the p53 gene, is considered to be essential for the normal development of stratified epithelia including urothelium. To examine possible roles of p63 in urothelial tumorigenesis, p63 expression was systematically examined in normal urothelium, low-grade papillary noninvasive (LPN) urothelial tumours, and high-grade or invasive carcinomas, using either an isoform-nonspecific or a Delta N-isoform-specific antibody. Expression profiles of p63 were also analysed in cultured cells. Immunoreactivity with the two antibodies was virtually identical in tissue samples examined. Basal and intermediate cell layers of normal urothelium showed intense nuclear p63 immunostaining. This normal staining pattern was preserved in a majority of LPN tumours, whereas it was frequently impaired in high-grade or muscle-invasive carcinomas. At the mRNA level, Delta Np63 expression predominated over TAp63, and amounts of Delta Np63 mRNA correlated with p63 immunoreactivity, confirming that Delta Np63 accounts for p63 expressed in urothelial tissues. In cultured cells, Delta Np63 was also expressed in low-grade tumour cells as well as normal urothelial cells, but undetectable in high-grade aggressive carcinoma cells. Interestingly, impaired Delta Np63 expression significantly associated with reduced beta-catenin expression that was possibly related to progression of urothelial neoplasms. Thus, impaired Delta Np63 expression characterises aggressive phenotypes of urothelial neoplasms.

Urokinase and the urokinase receptor: association with in vitro invasiveness of human bladder cancer cell lines

BACKGROUND AND PURPOSE

The plasminogen activators urokinase and tissue plasminogen activator are enzymes that degrade proteins in tissue basement membranes and the extracellular matrix (a biomolecular complex surrounding individual cells in tissues that serves as a barrier between the cells and the vascular and lymph systems). The action of these enzymes allows tumor cells to escape their local environment and metastasize. Plasminogen activator activity can be influenced by the urokinase receptor, which is expressed on the surface of cells, and by the plasminogen activator inhibitors 1 and 2. Because bladder tumors differ in their propensity to invade local areas and distant sites, we studied the expression of both plasminogen activators, the two plasminogen activator inhibitors, and the urokinase receptor in four human bladder cancer cell lines (RT4, 253J, EJ, and T24) to see if there was an association between the expression of these proteins and tumor cell invasiveness in vitro.

METHODS

The expression of urokinase, tissue plasminogen activator, and the two inhibitors was measured by enzyme-linked immunosorbent assays of serum-free, cell-conditioned media (i.e., culture fluids). Cell surface expression of the urokinase receptor was assayed by flow cytometry, using an anti-receptor monoclonal antibody (Mab3936). The invasive capacity of untreated cells and of cells exposed to exogenous, high-molecular-weight urokinase was analyzed by use of Matrigel invasion chambers.

RESULTS

The four bladder cancer cell lines demonstrated differential expression of both plasminogen activators and both inhibitors; three of the cell lines (T24, EJ, and 253J) expressed the urokinase receptor. The four cell lines differed in their invasive potential in vitro. Neither expression of tissue plasminogen activator nor production of the inhibitors appeared to influence Matrigel invasion. EJ cells and 253J cells produced the highest levels of urokinase and demonstrated the greatest propensity for invasion; T24 cells, which produced only small amounts of urokinase, exhibited a low invasive potential. Pretreatment of T24 cells with exogenous high-molecular-weight urokinase markedly increased their invasiveness. Similar pretreatment of EJ and 253J cells increased their invasiveness as well. RT4 cells, which lacked urokinase receptor expression but produced moderate amounts of urokinase, were not invasive and did not become so after exposure to exogenous high-molecular-weight urokinase. Binding of Mab3936 to urokinase receptors inhibited Matrigel invasion.

CONCLUSIONS

To our knowledge, this is the first study demonstrating that bladder tumor cells express the urokinase receptor and that both receptor expression and urokinase expression are required for bladder tumor cell invasion in vitro.

Efficient gene transfer into human hepatocytes by baculovirus vectors

Viral vectors are the most efficient tools for gene delivery, and the search for tissue-specific infecting viruses is important for the development of in vivo gene therapy strategies. The baculovirus Autographa californica nuclear polyhedrosis virus is widely used as a vector for expression of foreign genes in insect cells, and its host specificity is supposed to be restricted to arthropods. Here we demonstrate that recombinant A. californica nuclear polyhedrosis virus is efficiently taken up by human hepatocytes via an endosomal pathway. High-level reporter gene expression from heterologous promoters was observed in human and rabbit hepatocytes in vitro. Mouse hepatocytes and some other epithelial cell types are targeted at a considerably lower rate. The efficiency of gene transfer by baculovirus considerably exceeds that obtained by calcium phosphate or lipid transfection. These properties of baculovirus suggest a use for it as a vector for liver-directed gene transfer but highlight a potential risk in handling certain recombinant baculoviruses.

Establishment and characterization of a new cell line from human bladder cancer (JMSU1)

A new human bladder cancer cell line designated JMSU1 has been established from malignant ascitic fluid of a 75-year-old Japanese man with bladder cancer, and maintained in culture for more than 7 years and over 240 passages. Inverted phase-contrast microscopy revealed that JMSU1 was composed of morphologically distinct cells (polygonal to spindle-shaped cells), showing morphological heterogeneity in vitro. Histological examination of xenografts showed poorly differentiated transitional cell carcinoma, resembling the original tumor. Immunohistochemical staining for cytokeratin and electron microscopic examination suggested that JMSU1 was of epithelial origin. Chromosome analysis gave a modal number of 69 with no Y chromosome. Isozyme analysis (LDH, G6PD, and NP) showed the mobility pattern of human type B. DNA fingerprint analysis demonstrated that there was no cross-culture contamination of JMSU1 during the passages. In conclusion, a newly established and well-characterized cell line, JMSU1, offers promising material for the investigation of the biological properties of bladder cancer.

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.

E-cadherin-mediated cell-cell adhesion prevents invasiveness of human carcinoma cells

The ability of carcinomas to invade and to metastasize largely depends on the degree of epithelial differentiation within the tumors, i.e., poorly differentiated being more invasive than well-differentiated carcinomas. Here we confirmed this correlation by examining various human cell lines derived from bladder, breast, lung, and pancreas carcinomas. We found that carcinoma cell lines with an epithelioid phenotype were noninvasive and expressed the epithelium-specific cell-cell adhesion molecule E-cadherin (also known as Arc-1, uvomorulin, and cell-CAM 120/80), as visualized by immunofluorescence microscopy and by Western and Northern blotting, whereas carcinoma cell lines with a fibroblastoid phenotype were invasive and had lost E-cadherin expression. Invasiveness of these latter cells could be prevented by transfection with E-cadherin cDNA and was again induced by treatment of the transfected cells with anti-E-cadherin mAbs. These findings indicate that the selective loss of E-cadherin expression can generate dedifferentiation and invasiveness of human carcinoma cells, and they suggest further that E-cadherin acts as an invasion suppressor.

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.

Human-mouse hybrids carrying fragments of single human chromosomes selected by tumor growth

Fusion of human EJ bladder carcinoma cells to mouse C127 cells, with direct selection for tumor growth, gave rise to hybrid cells in which the human chromosome complement had been reduced dramatically, while selectively retaining the activated HRAS1 at chromosome band 11p15. A single-component hybrid retaining only part of human chromosome 11 is described in detail. Our results suggest a novel and general approach for investigating the chromosomal basis of neoplastic change and for subchromosomal mapping of and enrichment cloning for the human genome.

Characterization of cell lines derived from a multiply aneuploid human bladder transitional-cell carcinoma, UCRU-BL-13

A series of cultured cell lines (designated UCRU-BL-13) has been established from different serial passages of a multiply aneuploid human bladder transitional-cell carcinoma xenografted in nude mice. Serial passage of the xenografts in vivo and of the cell lines in vitro was accompanied by shifts in the tumor ploidy, with dominance of different major peaks. Despite this, the expression of tumor markers remained constant, and consistent chromosomal markers were observed both in the 8th xenograft passage and in a subline in tissue culture established over a year apart. Chromosomal numbers reflected the predominant aneuploid peaks observed; consistent numerical and structural changes included a marker derived from chromosome 1, 8p-, -10, 11q+, and 17q+. The cell line derived from the initial xenograft comprised a mixture of transitional, adenocarcinoma and squamous carcinoma cells in early passage, but adenocarcinoma cells were absent from later passages. The lines expressed the B-blood-group antigen, histocompatibility antigens, receptors for transferrin and EGF, and reacted with a series of monoclonal antibodies (MAbs) directed to malignant human epithelial cell lines. These lines provide a model for studying the evolution of tumor heterogeneity and drug resistance in bladder carcinoma exhibiting multiple aneuploidy.

Cytokeratins in normal and malignant transitional epithelium. Maintenance of expression of urothelial differentiation features in transitional cell carcinomas and bladder carcinoma cell culture lines

The pattern of cytokeratins expressed in normal urothelium has been compared with that of various forms of transitional cell carcinomas (TCCs; 21 cases) and cultured bladder carcinoma cell lines, using immunolocalization and gel electrophoretic techniques. In normal urothelium, all simple-epithelium-type cytokeratins (polypeptides 7, 8, 18, 19) were detected in all cell layers, whereas antibodies to cytokeratins typical for stratified epithelia reacted with certain basal cells only or, in the case of cytokeratin 13, with cells of the basal and intermediate layers. This pattern was essentially maintained in low-grade (G1, G1/2) TCCs but was remarkably modified in G2 TCCs. In G3 TCCs simple-epithelial cytokeratins were predominant whereas the amounts of component 13 were greatly reduced. Squamous metaplasia was accompanied generally by increased or new expression of some stratified-epithelial cytokeratins. The cytokeratin patterns of cell culture lines RT-112 and RT-4 resembled those of G1 and G2 TCCs, whereas cell line T-24 was comparable to G3 carcinomas. The cell line EJ showed a markedly different pattern. The results indicate that, in the cell layers of the urothelium, the synthesis of stratification-related cytokeratins such as component 13 is inversely oriented compared with that in other stratified epithelia where these proteins are suprabasally expressed, that TCCs retain certain intrinsic cytoskeletal features of urothelium, and that different TCCs can be distinguished by their cytokeratin patterns. The potential value of these observations in histopathologic and cytologic diagnoses is discussed.

Bladder cancer cell line cross-contamination: identification using a locus-specific minisatellite probe

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Establishment and characterization of a new human bladder cancer cell line showing features of squamous and glandular differentiation

Tumour-cell heterogeneity has been studied in a continuous cell line, UCRU-BL-17CL, established from a xenografted human primary bladder carcinoma. The cell line, grown in vitro for more than 30 generations, reflects the pathology of both the xenograft from which it was derived and the original human tumour. It comprises mainly adenocarcinoma cells which secrete mucin in vitro, as well as squamous and transitional carcinoma cells. Features of both adenocarcinomatous and squamous differentiation have been observed within the same cell. The line expresses ABH blood group isoantigens, binds to peanut lectin and reacts with monoclonal antibodies (MAbs) raised against keratin and against normal and malignant epithelial cells. It also reacts with MAbs against ras p21 proteins and the epidermal growth factor receptor (EGFR). It shows high levels of lactic acid dehydrogenase isozyme 5, consistent with a high-grade tumour, forms colonies in methylcellulose and is tumorigenic in nude mice. The karyotype (human) shows many marker chromosomes, consistent with expression of EGF receptors and ras p21 proteins, and an 11:13 translocation. DNA content, as studied by flow cytometry, reveals a shift from tetraploid to near triploid. This line may provide a useful model for studies of the histogenesis of bladder cancer and the relationship between transitional-cell carcinoma and the other histological subtypes of this disease.

Tumorigenicity of T24 urinary bladder carcinoma cell sublines

Two sublines of the T24 human urinary bladder carcinoma cell line which differ in tumorigenicity in nude mice have been studied (T24A and T24P). T24A obtained directly from the American Type Culture Collection is non-tumorigenic while T24P obtained after multiple passages in several NCI laboratories produces tumors in 100% of inoculated mice. T24P cells differ morphologically from T24A, have a higher saturation density, are less serum-dependent for growth, and are more sensitive to ouabain toxicity. Cytogenetic studies show that the 2 sublines differ significantly in chromosome number, with a modal chromosome range of 76-89 in T24A and a modal chromosome number of 48-51 in T24P. Southern blot analysis of MspI cleaved T24A and T24P DNAs with the H-ras SmaI probe indicates that both contain only the activated mutant allele originally described in T24. Northern blot analysis shows equal amounts of the 1.2kB ras polyadenylated message, and immunoblotting with rasHa antibody demonstrates no significant difference in the amounts of ras proteins. These results indicate that 2 sublines of a ras oncogene-containing tumor cell line can differ greatly in tumorigenicity and other in vitro characteristics of transformation, and yet have similar expression of the ras oncogene. The fact that the tumorigenic cell line contains fewer chromosomes suggests that tumorigenicity may be related to the loss of some regulatory gene.

HRAS1-selected chromosome transfer generates markers that colocalize aniridia- and genitourinary dysplasia-associated translocation breakpoints and the Wilms tumor gene within band 11p13

We show that chromosome-mediated gene transfer can provide an enriched source of DNA markers for predetermined, subchromosomal regions of the human genome. Forty-four human DNA recombinants isolated from a HRAS1-selected chromosome-mediated gene transformant map exclusively to chromosome 11, with several sublocalizing to the Wilms tumor region at 11p13. We present a detailed molecular map of the deletion chromosomes 11 from five WAGR (Wilms tumor/aniridia/genitourinary abnormalities/mental retardation) syndrome patients, three of which are at the limits of cytogenetic resolution but shown here to be molecularly distinguishable and overlapping. We can define ten distinct regions of the short arm of chromosome 11, five of which subdivide band 11p13. We also map two independent 11p13 translocation breakpoints to within the smallest region of overlap defined by the WAGR deletions. The first comes from a patient with familial aniridia, and the second from a patient with Potter facies and genitourinary dysplasia. The close similarities in map location and affected cell lineage for Wilms tumor and genitourinary dysplasia suggest that they may be alternative manifestations of mutation at the same locus.

HRAS1-selected, chromosome-mediated transformants vary in phenotype in vitro and tumorigenic potential in vivo

Transfection of mouse C127 cells with mitotic chromosomes isolated from a human EJ bladder carcinoma cell line gave rise, at high frequency, to foci of transformed cells. Independent, HRAS1-selected chromosome-mediated transformants displayed distinctive cellular morphologies in monolayer culture and colony-forming abilities in low-melting-point agarose. Subcutaneous inoculation of neonatally thymectomized, Ara-C-protected, total-body-irradiated CBA mice was used to compare the tumorigenic potential of each transformant. Significant quantitative and qualitative differences in tumorigenicity were found between transformants which correlated with differences in malignant phenotype observed in vitro. The sensitivity of the tumorigenicity assay is such that rare transformation events can be selected directly in vivo.

Gene mapping and physical arrangements of human chromatin in transformed, hybrid cells: fluorescent and autoradiographic in situ hybridization compared

We compare a fluorescent in situ hybridization technique, using N-acetoxy-2-acetylaminofluorene (N-ACO-AAF) modified DNA adducts, with 3H-labeled DNA in situ hybridization for visualizing human transgenomes in HRAS1-selected, chromosome-mediated gene transfer (CMGT), and mapping chromosomal SV40 in an SV40-transformed, human-mouse hybrid cell line. We demonstrate that individual HRAS1-CMGTs may contain multiple fragments of human chromatin. We deduce that the CMGT process can involve interstitial loss of mouse chromatin. We conclude that the N-ACO-AAF technique gives finer resolution than 3H-labeled in situ hybridization. However, 3H-labeling is more sensitive and has allowed us to sublocalize SV40 in C121 to the region 7q31-35.

Selective suppression of metastasis but not tumorigenicity of a mouse lung carcinoma by cell hybridization

Somatic cell hybrids were produced by polyethylene glycol-induced cell fusion between metastatic CMT 167 (HGPRT-/OUAR) C57BL/Icrfat mouse lung carcinoma cells and 2 non-metastatic cell lines: C3H/He mouse L-M(TK-) cells of mesenchymal origin and EJ (OUAS) human bladder carcinoma cells. Fusion of 2 different CMT167 (HGPRT-) clones with L-M(TK-) cells followed by selection in HMT medium gave rise to 14 intraspecific hybrids, which were shown to express H-2 antigens specific for both the C57 and C3H mouse strains. Three interspecific hybrids arising from fusion of EJ(OUAS) and CMT167(HGPRT-/OUAR) cells were selected in HMT/ouabain medium and characterized by human isozyme analysis. All the hybrids produced large tumours after subcutaneous inoculation of 5 X 10(5) cells into adult athymic nu/nu mice. The intraspecific hybrid tumours were predominantly sarcomatous (mesenchymal) in structure but a few contained epithelial acini. Metastatic ability (as assessed by production of lung metastases) was completely suppressed in 13 of the 14 mouse/mouse hybrid cell clones. These results suggest that tumorigenicity, tumour structure and the ability to metastasize are expressed independently. The interspecific hybrids, which had not retained a full human chromosome complement, produced metastatic tumours that remained epithelial in structure.

Development of highly immunogenic variants of a rat fibrosarcoma line during in vitro cultivation

Rat fibrosarcoma KMT-17 cells decreased in tumorigenicity when cultured in vitro. Eight clones derived from cultured KMT-17 cell lines (c-KMT-17) were examined for their tumorigenicity, immunosensitivity, and immunogenicity. All the clones were less or nontumorigenic in normal syngeneic rats than KMT-17 cells maintained in vivo. All eight clones produced tumors in rats immunosuppressed with 600 rad 60Co; differences in degree of tumorigenicity were seen among clones in rats irradiated with 250 rad 60Co. Although immunosensitivity of the eight clones to complement-dependent and cell-mediated cytotoxicity was the same or less than that of KMT-17 cells, al leight clones induced greater transplantation resistance to KMT-17 than KMT-17 itself. Cold target inhibition tests demonstrated new antigens in a highly immunogenic variant in addition to the original tumor associated antigen (TAA). New glycolipids, not observed in KMT-17 cells, were demonstrated in the clones by thin layer chromatography. These results suggest that new antigens appearing during culture of KMT-17 may act as helper antigens for TAA, increasing the immunogenicity and decreasing the tumorigenicity of the cultured cells.

Genetic instability of cell lines derived from a single human small cell carcinoma of the lung

Specimens from a human small cell carcinoma of the lung were established as a cell line in vitro. Flow cytometric DNA analysis demonstrated only one tumor cell population in the parent tumor as well as in the early passages in vitro. After six passages in vitro, two new subpopulations with different DNA content appeared. By cloning, permanent cell lines were established from the new subpopulations, whereas the original population stopped growing. The cloned cell lines were characterized by morphology, chromosomes analysis, electron microscopy and plating efficiency; the stability of the DNA content was examined regularly by flow cytometric DNA analysis and instability was found in one of the cloned cell lines. Chromosome analysis showed that the cloned cell lines consisted of more than one population after 17 in vitro passages. Both cloned cell lines produced tumors in nude mice. Genetic instability was demonstrated in these mouse-grown tumors as well. Development of resistance to antineoplastic treatment may be due to heterogeneity in sensitivity among subpopulations in a tumor. Isolation of populations with different DNA contents allows the study of interaction between subpopulations and the observations provide evidence in support of the hypothesis of clonal evolution.

Chemosensitivity measurements of human tumour cells by soft agar assays are influenced by the culture conditions

To investigate the influence of culture conditions on the in vitro responses of tumour cells to anticancer drugs, the sensitivities observed with the soft agar methods of Hamburger & Salmon (1977) (H-S) and of Courtenay & Mills (1978) (C-M) were compared. In all cases the ID50 values were determined from dose-response curves. Six human tumour cell lines exposed to 10 different agents, and 9 patients' melanomas exposed to 5 different agents, were examined. In the studies of cell lines the H-S method gave higher sensitivity values than the C-M method in 38 out of 52 cases, whereas in 14 cases the results were the same. In the patients' tumours the H-S method gave higher sensitivity in 21 of 35 cases, equal sensitivity in 11, and lower sensitivity in 3 cases. In many instances the ID50 values obtained with the two test systems differed by factors of 10 or more, both in the case of cell lines and tumour specimens. Systematic alterations in the culture conditions indicated that the presence or absence of rat erythrocytes is the most important factor responsible for the differences observed. Also, other factors, such as supplements (in the H-S method) and the use of different serum types, appeared to influence both colony growth and chemosensitivity.

Tumorigenicity of human lymphoblastoid cell lines, acquired during in vitro culture and associated with chromosome gains

Tumorigenicity of human lymphoma and lymphoblastoid B-cell lines was assessed by their ability to form growing and transplantable masses on subcutaneous inoculation into neonatally thymectomized, Ara-C-protected, total-body-irradiated mice. By these criteria, 12 lines of known malignant origin were tumorigenic, 11 lymphoblastoid lines, tested after less than one year of in vitro growth, were non-tumorigenic and 8/18 long-established lymphoblastoid lines produced transplantable tumours. All of the long-established lines had acquired karyotypic changes on prolonged culture, the predominant characteristic being a gain of whole chromosomes or of major chromosome segments. None showed the classical 8:14 translocation associated with Burkitt's lymphoma. Comparisons with nontumorigenic precursors (recovered from liquid nitrogen storage) and with other non-tumorigenic but chromosomally abnormal, lymphoblastoid lines suggest that imbalance of the dosage of genes carried on chromosomes 7,8 and 9 may be important in determining the tumorigenic phenotype.

Monoclonal antibodies to antigens associated with transitional cell carcinoma of the human urinary bladder. I. Determination of the selectivity of six antibodies by cell ELISA and immunofluorescence

Spleen cells from BALB/c mice immunized with cells derived from transitional cell carcinomas (TCC) of the human urinary bladder were fused with mouse myeloma Sp 2/0 Ag14 cells. Monoclonal antibodies from six established hybridomas were investigated for specificity in a cell ELISA and in indirect immunofluorescence against a large panel of fixed intact cells. Three of the antibodies reacted with half or more of the eight bladder tumors and with a few unrelated tumors. They did not react at all with malignant or normal cells of hematopoietic origin. A fourth antibody reacted with seven of eight bladder tumors. It also reacted weakly with a prostatic carcinoma, with five of six malignant or transformed B cell lines, and with a subpopulation of normal lymphocytes, but not with any of the other cells on the test panel. These four antibodies did not react with cells derived from normal urothelium. The results suggest that these antibodies might recognize cell-type-restricted antigens associated with malignancy. Another antibody reacted with almost all urothelium-derived cells. It also reacted with three of three melanomas but not with any other cells on the panel. The sixth antibody reacted with 32 of the 37 cells tested. The spectrum of reactivities displayed by the antibody suggested that it recognizes HLA antigens.

Growth in agar and tumor formation in immunologically incompetent mice as criteria for keratinocyte transformation

Established cell lines from 8 human squamous cell carcinomas (SCC) together with normal human keratinocytes, have been investigated for their ability to grow in soft agar and as xenografts when injected as a single cell suspension into immunologically incompetent mice. One of 8 SCC lines formed colonies with efficiencies greater than 1% in soft agar, and only 2 formed progressively growing tumors when injected into animals. It is concluded that these 2 criteria are not reliable markers of malignant transformation in squamous epithelia unless cytological criteria are also applied.

Identification of exposed surface glycoproteins of four human bladder carcinoma cell lines

Three cell surface protein-specific methods were used to radiolabel the major glycoproteins of four human bladder carcinoma cell lines: The well-differentiated lines RT112 and TR4 and more anaplastic lines T24 and EJ. Five acidic glycoproteins iodinated in all lines by the lactoperoxidase/125I method were designated CP-175/5.8-6.0 (apparent molecular weight X 10(-3)/pl of iodoprotein), GP-155/5.0-5.3, GP-145/4.9-5.2, GP-130/4.8-5.5 and GP-110/4.9-5.3. Another iodinated glycoprotein, GP-200/5.5-6.0, was prominently labelled in RT112 and RT4 but was not detected in T24 or EJ. GP-200 as well as GP-175, GP-155 and GP-145 were not detected by the galactose oxidase/NaB(3H)4 method and were poorly labelled by the neuraminidase-galactose oxidase/NaB(3H)4 and NaIO4/NaB(3H)4 labelling methods. The major sialogalactoproteins identified in the four lines by the neuraminidase-galactose oxidase/NaB(3H)4 and NaIO4/NaB(3H)4 methods were GP-130, and a duplet of GP-90 and GP-80 which were poorly iodinated by lactoperoxidase/125I. The galactose oxidase/NaB(3H)4 reaction was increased by between 4- and 10-fold and many additional glycoproteins were labelled after neuraminidase treatment, indicating that the cell surface galactose and N-acetylgalactosamine residues of glycoproteins are highly sialylated. In cell lines RT112 and RT4 there was prominent labelling of very high molecular weight sialogalactoconjugates that was not present in extracts of T24 and EJ.