Preclinical activity of a new platinum analogue,lobaplatin, in cisplatin-sensitive and -resistant human testicular,ovarian, and gastric carcinoma cell lines

Lobaplatin [1,2-diamminomethylcyclobutane-platinum(II) lactate] is a new platinum compound with interesting preclinical activity and apparently no nephro- or neurotoxicity that is currently undergoing clinical phase II studies. Little is known about the cross-resistance between cisplatin and lobaplatin. The activity of this new compound in comparison with cisplatin and carboplatin was evaluated in cisplatin-sensitive and cisplatin-resistant human testicular, gastric, and ovarian carcinoma cell lines using 96 h continuous drug exposure in a sulforhodamine-B assay. In three cisplatin-sensitive testicular carcinoma cell lines, lobaplatin and cisplatin showed comparable antitumor activity. The 50% growth-inhibitory concentrations (IC₅₀ values) determined for cisplatin ranged from 0.1 to 0.4 μM, and those found for lobaplatin ranged from 0.25 to 0.5 μM. Carboplatin showed markedly lower cytotoxicity in all cell lines tested. Lobaplatin was not cross-resistant to cisplatin in a 10-fold cisplatin-resistant testicular carcinoma cell line and showed only weak cross-resistance in a 20-fold cisplatin-resistant ovarian carcinoma cell line. In contrast, complete cross-resistance between cisplatin and lobaplatin occurred in two cisplatin-resistant human gastric carcinoma cell lines, which were 3.3- and 9-fold resistant to cisplatin and 3.1- and 6.5-fold resistant to lobaplatin, respectively. Furthermore, lobaplatin showed significant activity against cisplatin-resistant human ovarian and testicular carcinoma xenografts in vivo. These data indicate a high level of activity for lobaplatin at clinically achievable concentrations in drug-sensitive testicular, ovarian, and gastric carcinoma cell lines and a lack of complete cross-resistance to cisplatin. Further clinical development of lobaplatin is clearly warranted.     

Delineation of the 6p22 amplification unit in urinary bladder carcinoma cell lines

Eight cell lines from transitional cell carcinoma of the urinary bladder were analyzed by comparative genomic hybridization. All tumor lines exhibited frequent chromosome gains (11.5/cell line) and losses (8.4/cell line). In six cell lines, gain of chromosome 5p was associated with gains of 6p and 20q. In five of these cell lines, amplification of parts of 6p was observed. Cytogenetic investigation combined with fluorescence in situ hybridization analysis revealed typical marker chromosomes with homogeneously staining regions (HSRs) containing material from 6p. By hybridizing individual yeast artificial chromosome probes from a chromosome 6p contig to these HSRs, a contig of three yeast artificial chromosomes common to all 6p HSRs was identified that spans less than 2 Mb. The genes SOX4 and PRL were shown to map to this region and to be coamplified in the cell lines. However, SOX4 was not overexpressed in any cell line and PRL was not expressed at all. Thus, the presumptive 6p oncogene remains to be conclusively identified.     

Response of four human ovarian carcinoma cell lines to ALL-TRANS retinoic acid: Relationship with induction of differentiation and retinoic acid receptor expression

The response of 4 human ovarian carcinoma cell lines to retinoic acid was found to be related to the histological type and degree of differentiation of these tumor cells. The 2 serous cell lines NIHOVCAR₃ and OVCCR₁ were the most sensitive to the antiproliferative effect of RA. This inhibition was associated with morphological and biological changes that were indicative of differentiation. The undifferentiated IGROV₁ cell line was not affected by RA. Since the effects of RA are thought to be mediated by nuclear retinoic acid receptors (RARs), the expression of RARs in human ovarian cancer cells was studied. RARα was detected as mRNA species of 3.1 and 2.6 kb in all 4 cell lines. RARβ was not detected in any of the cell lines, while RARγ (3 kb) was expressed in all of the ovarian cancer cells but at a very low level in the RA-resistant IGROV₁ cells.     

Molecular biologic characteristics of seven new cell lines of squamous cell carcinomas of the head and neck and comparison to fresh tumor tissue

BACKGROUND: Squamous cell carcinoma (SCC) is the most frequent malignant tumor of the upper aerodigestive tract. Cell lines of these tumors facilitate the investigation of various tumor biological parameters. This study was conducted to compare molecular biologic characteristics between cell lines and fresh tumor tissue. METHODS: In seven SCC-derived cell lines, cytokeratin 5/6 and cytokeratin 19 expression, DNA content, chromosome aberrations and tumorigenicity were assessed in nude rats. Unbalanced numerical and structural chromosomal aberrations were investigated by comparative genomic hybridization (CGH), and results were compared to those obtained in fresh tumor tissues of the same patients. RESULTS: All cell lines expressed cytokeratins 5/6 and 19, indicating their epidermoid origin. Tumor growth after transplantation into nude rats occurred in five of seven cell lines. Routine histology and immunohistochemical examinations confirmed SCC. Aneuploidy was detected in all cell lines, with a 2c deviation index ranging from 1.9 through 9.5 and a 5c exceeding rate ranging from 2.6 through 36.7%. The most frequent chromosomal aberrations in cell lines were overrepresentations of chromosomal material on chromosomes 15q, 7p (5 cases each), 3q, 5p (4 cases each), and 11q and 17q (3 cases each) and losses of chromosomal material on chromosomes 3p, 18q (3 cases each), and 19p and 7q (2 cases each). Comparing these results to CGH analysis of fresh tumor tissue from the same patients, overrepresentations of chromosomal material on 10q, 20q and 21q, along with loss of chromosomal material on 4q was detected more frequently in primary tumors, whereas overrepresentations on 7p and loss of chromosomal material on 7q were more frequently detected in cell lines. Nevertheless, there was a high degree of similarity of chromosomal alterations in cell lines and corresponding fresh tumor tissue. CONCLUSION: The data suggest a high degree of genetic similarity between tumor cells of cell lines and the tumors from which they were derived. Therefore, these cell lines can serve as an accurate model to investigate cell biology of SCC in vitro.     

Different mechanisms of mitotic instability in cancer cell lines

Chromosomes of human malignant tumours display not only structural recombinations but also a wide variety of mostly non-random numerical aberrations. However, only little is known about the mechanisms leading to recurrent aneuploidies. We therefore investigated whether the malsegregation of specific chromosomes is due to a defect of the mitotic spindle apparatus. We analyzed mitoses of cell lines of six gliomas and of one breast carcinoma by combined immunohistochemistry and fluorescence in situ hybridization for non-disjunction of chromosomes 7, 8, 10, 12, 17, and 18 and observed three different phenomena. i) Five of six glioma cell lines showed a bipolar spindle but displayed a chromosome-specific malsegregation of all chromosomes studied with high but significantly different frequencies. Chromosomes 7 and 8 showed non-disjunction in about 75 and 50%, respectively. Although chromosomes 10, 12, 17, and 18 displayed equal separation during mitosis in 72, 86, 73, and 78%, respectively, a relevant percentage of an average of 24% of dividing cells showed even malsegregation of these chromosomes. ii) Only one of the glioma cell lines displayed multipolar spindles in one-third of the investigated cells resulting in non-specific aneuploidy. iii) The breast cancer cell line MCF7 displayed a bipolar spindle, but high frequencies of non-disjunction of all six investigated chromosomes but without preferential loss or gain of specific chromosomes indicating a different mechanism of chromosome malsegregation. In a small percentage of mitoses the chromatids of both homologous chromosomes were not separated mimicking the mechanism in the first meiotic division. This mechanism of double non-disjunction, not detectable by conventional cytogenetic analysis, procreates cell clones with genomic separation for particular chromosomes resulting in homozygosity for mutations which had been present heterozygously in the initial tumour cells.     

Characterization of p53 gene mutations in esophageal squamous cell carcinoma cell lines: Increased frequency and different spectrum of mutations from primary tumors

We screened 29 human esophageal squamous cell carcinoma (ESC) cell lines for mutations of the p53 gene through all coding exons and exon—intron junctions. Mutations were found in 22 cell lines (76%), consisting of 20 single-base substitutions, 2 small deletions and 1 single-base insertion. Out of 20 single-base substitution, 5 were located at the exon—intron junctions and mRNAs with abnormal splicing were detected by RT-PCR in 4 of them. A G:C to T:A transversion, which occurred rather frequently in resected tumors of ESC, was observed in only 1 cell line, and, instead, frequent transitions at CpG sites were detected. We also examined 65 fresh tumor materials, from all of which we tried to establish cell lines, and detected mutations in 26 samples (40%). Compared with the results in these fresh tumor materials, the mutation incidence in cell lines was significantly high and the mutation spectrum was also different. From these 65 tumors, 10 cell lines were established, including 3 cell lines from 26 tumors with p53 mutations and 7 cell lines from 39 without mutations, which indicates that there was no significant correlation between the status of the p53 gene in each fresh tumor and its establishment as a cell line. In 7 cell lines established from mutation-free tumors, newly acquired mutations were detected in 5, which suggests that mutations might occur during the process of establishing cell lines. © 1996 Wiley-Liss, Inc.     

Chromophilic renal cell carcinoma: cytomorphological and cytogenetic characterisation of four permanent cell lines.

Chromophilic renal cell carcinoma is a distinct type of human renal cancer, only recently recognised and defined by its characteristic histomorphological aspect and cytogenetic aberrations. We are the first to report on the establishment and cytogenetic characterisation of a panel of four permanent cell lines, i.e. chromphi-1, -2, -3 and -4, derived from strictly defined renal cell carcinomas (RCCs) of the chromophilic type and kept in continuous culture for up to 5 years. Immunohistochemistry revealed coexpression of vimentin and cytokeratins in all cell lines the cytokeratin polypeptide patterns, however, varying between the different cell lines. By light and transmission electron microscopy, various amounts of cytoplasmatic glycogen deposition were observed, being most pronounced in chromphi-3 and -4. The mean population doubling time ranged from 24 h (chromphi-1) to 51 h (chromphi-4). Chromphi-1 tumour cells produced slowly growing tumours in nude mice using the subrenal capsule assay. In all cell lines, cytogenetic analysis revealed numerical chromosomal aberrations known to be characteristic for chromophilic RCCs, i.e. loss of the Y chromosome, tri- or tetrasomy of chromosomes 7 and 17 as well as various combinations of additional structural and numerical chromosomal aberrations. Karyological aberrations were least pronounced in chromphi-2 and most complex in chromphi-1. Chromosomal aberrations typically affecting the short arm of chromosome 3 in clear cell RCCs were not observed in any of our cell lines.     

Molecular cytogenetic characterization of primary cultures and established cell lines from non-medullary thyroid tumors

To further delineate the role of chromosomal aberrations in non-medullary thyroid tumors, we performed cytogenetic analyses of established thyroid cancer cell lines and primary tumors using spectral karyotyping (SKY), G-banding and comparative genomic hybridization (CGH). Five of the primary thyroid tumors revealed an abnormal karyotype. In a follicular thyroid carcinoma, we observed two translocations t(2;10), t(2;5) and losses of chromosomes 10p and 22. In a papillary thyroid carcinoma (PTC), a balanced translocation t(3;15) was revealed, while a case of metastatic PTC carried several clonal translocations involving ten different chromosomes. Numerical aberrations were observed in two of the five follicular adenomas analyzed, both leading to gain of chromosome 7 material. Furthermore, we cytogenetically characterized the three established thyroid cancer cell lines CGTH W-1, ARO and DRO. SKY, in combination with G-banding, revealed structural and numerical karyotypic abnormalities in all three cell lines and the breakpoint regions partly overlapped those of the primary tumors. The copy number changes detected by CGH correlated well with the karyotypic findings and demonstrated high-level amplifications in chromosomes 1, 5, 7, 8, 9, 11 and 19. The results provide evidence of chromosomal regions involved in non-medullary thyroid tumorigenesis, while further characterization of the observed translocations may lead to the identification of novel fusion oncogenes for thyroid cancer.     

ESTABLISHMENT OF A MURINE ASCITES HEPATOMA CELL LINE H_(22)-F_(25)/L AND ITS BIOLOGICAL CHARACTERISTICS

Having been passed for 160 generations, a cell linedesignated as H22-F25/L was established from a murine tumorlymphatic metastatlc model H22-F25 which had been set up in our college. The cell line was in suspension culture with a rapid proliferation and stable growth. The peak tune of cell division and proliferation was 48 and 96 hours after culture. In a week, the cell number was Increased by 25 tunes. H22-F25/L still keeps the features of a poorly differentiated cancer. Its tumor inducing rate (in vivo)was 100% in 615 mice. Lymph node metastasis rate was 50% and pulmonary metastasis rate 10%. H22- F25/ L Is a population of heterogenetlc tumor cells Including 2 stem cell lines (the model number of chromosomes being 43 in 40% tumor cells and 86 in 32%) and some side lines. The common marker chromosomes M1, M2, M3 and M4 were present in all stem and side lines.     

Cytogenetic studies on 3 esophageal cancer cell lines

The cytogenetic studies on three esophageal cancer cell lines established in China were done. Thirty metaphases showing suitable chromosome length and good G-banding pattern from each of the cell lines were chosen and subjected to karyological analysis. The typical karyotypes from these cell lines were listed, and the variation of chromosome number as well as the morphological characteristics, possible sources and the incidence of the marker chromosomes were analysed. Eca 109 is the cell line first established and used extensively in China. A strictly regular karyotype pattern was found in it: the modal number of chromosomes being 63-64; the number of each type of chromosome varying between 1-5; a distal deletion of short arm of chromosome No. 1 being discernible in all metaphases, with break sites located within 1p22-1p33. Also a distal deletion of long arm of chromosome No. 4 was usually visible. There were seven marker chromosomes with high incidence. Among them, M1 marker chromosome was a large subacrocentric chromosome which was observed in the early passages of this cell line. The chromosome number of Ec 17 cell line was usually subtetraploid. In addition to the numerical variation in some of the chromosomes, six marker chromosomes were usually observed. Among them, M1 involved reciprocal translocation between chromosome No. 1 and No. 4. M3 of Ec 17 was in correspondence with M5 of Eca 109. Both were Rob (13q;14q). The chromosome number of Ec 56 was usually subtetraploid, and in addition to the numerical variation in some of the chromosomes, seven marker chromosomes were usually observed.     

Preclinical activity of a new platinum analogue, lobaplatin, in cisplatin-sensitive and -resistant human testicular, ovarian, and gastric carcinoma cell lines

Lobaplatin [1,2-diamminomethylcyclobutane-platinum(II) lactate] is a new platinum compound with interesting preclinical activity and apparently no nephro- or neurotoxicity that is currently undergoing clinical phase II studies. Little is known about the cross-resistance between cisplatin and lobaplatin. The activity of this new compound in comparison with cisplatin and carboplatin was evaluated in cisplatin-sensitive and cisplatin-resistant human testicular, gastric, and ovarian carcinoma cell lines using 96 h continuous drug exposure in a sulforhodamine-B assay. In three cisplatin-sensitive testicular carcinoma cell lines, lobaplatin and cisplatin showed comparable antitumor activity. The 50% growth-inhibitory concentrations (IC₅₀ values) determined for cisplatin ranged from 0.1 to 0.4 M, and those found for lobaplatin ranged from 0.25 to 0.5 M. Carboplatin showed markedly lower cytotoxicity in all cell lines tested. Lobaplatin was not cross-resistant to cisplatin in a 10-fold cisplatin-resistant testicular carcinoma cell line and showed only weak cross-resistance in a 20-fold cisplatin-resistant ovarian carcinoma cell line. In contrast, complete cross-resistance between cisplatin and lobaplatin occurred in two cisplatin-resistant human gastric carcinoma cell lines, which were 3.3- and 9-fold resistant to cisplatin and 3.1- and 6.5-fold resistant to lobaplatin, respectively. Furthermore, lobaplatin showed significant activity against cisplatin-resistant human ovarian and testicular carcinoma xenografts in vivo. These data indicate a high level of activity for lobaplatin at clinically achievable concentrations in drug-sensitive testicular, ovarian, and gastric carcinoma cell lines and a lack of complete cross-resistance to cisplatin. Further clinical development of lobaplatin is clearly warranted.This work was supported in part by a grant from Asta Medica, D-6000 Frankfurt 1, Germany     

Comparative properties of five human ovarian adenocarcinoma cell lines

We describe the derivation of three human ovarian carcinoma cell lines and the comparison of their properties with two previously described cell lines of like histology (SKOV-3 and CAOV-3). Two of the new lines (HOC-1 and HOC-7) were derived from separate ascites tumors (at 9-month intervals) of a patient with well-differentiated serous adenocarcinoma of the ovary. The third new line, HEY, was derived from a human ovarian cancer xenograft (HX-62) originally grown from a peritoneal deposit of a patient with moderately differentiated papillary cystadenocarcinoma of the ovary. The cell lines demonstrated differential ability to grow in semisolid culture and as xenografts in immunologically deprived CBA/CJ mice. Dose-response curves were generated for clonogenic cell survival of cells exposed to common chemotherapeutic agents; one of the lines (HEY) shows a degree of resistance to the alkylating agent cis-diamminedichloroplatinum(II) (cis-platinum). Common karyological features included structural abnormalities of chromosomes 3 and 11. Heterogeneity of expression of ovarian tumor-associated antigens was documented.     

Hemoperitoneum is an initial presentation of recurrent granulosa cell tumors of the ovary

Ovarian sex cord-stromal tumors account for less than 5% of all ovarian carcinoma, of which granulosa cell tumors account for 70%. These tumors have a propensity for indolent growth and late recurrence; they may even occur 25 years after initial treatment. We report a 44-year-old woman with hemoperitoneum (acute abdomen) after initial treatment 10 years earlier for granulosa cell tumor of the ovary. This case re-emphasizes the need for long-term follow-up in patients with stromal cell tumors of the ovary and considers the possibility of recurrence when presented with acute abdomen after conservative treatment.     

Cytogenetic evidence of the multistep origin of head and neck squamous cell carcinomas.

BACKGROUND: Head and neck squamous cell carcinomas are associated with tobacco and alcohol use; therefore, the incidence of this type of tumor is expected to rise in the future as a result of the increasing numbers of female and adolescent smokers. Previous reports of cytogenetic analysis of this type of tumor have implicated a number of chromosomal regions in recurring changes, but no clear pattern of characteristic changes has emerged. PURPOSE: We have undertaken cytogenetic analysis of 10 cell lines which were established from squamous cell carcinomas of the head and neck, to determine the possible sites of additional tumor suppressor genes and oncogenes that may contribute to malignant transformation. METHODS: Metaphases were harvested from cultures of cells in the exponential growth phase, following exposure to Colcemid (demecolcine) at a final concentration of 30 ng/mL for 5 hours. Air-dried slides were G-banded using trypsin and Giemsa. Fifteen metaphases were photographed and fully karyotyped. RESULTS: We observed that several chromosomal regions were lost at high frequency, including 18q (10 of 10 lines), 10p (eight of 10 lines), 3p (six of 10 lines), 8p (seven of 10 lines), and the short arms of the acrocentric chromosomes (seven of 10 lines). Nine of 10 lines had additional copies of 7p. We also noted clustering of breakpoints in a number of chromosome bands, including 1p22, 10q11.2, 11q13, and the short arms of the acrocentric chromosomes. CONCLUSION: The observation of loss of multiple chromosomal regions in a significant number of lines analyzed is consistent with the theory that tumorigenesis occurs as the result of the accumulation of a number of genetic alterations, as proposed for colorectal carcinoma. The high frequency with which these changes are seen suggests that genes located in these regions have a role in the etiology of this type of tumor.     

Anti-transferrin receptor antibody linked to Pseudomonas exotoxin as a model immunotoxin in human ovarian carcinoma cell lines

The present in vitro study was performed to evaluate the potential usefulness of immunotoxins in treating human ovarian carcinomas. A monoclonal antibody against the human transferrin receptor was covalently linked to Pseudomonas exotoxin. The activity of this immunotoxin (anti-TFR-PE) was studied in five ovarian carcinoma cell lines, a breast carcinoma cell line (MCF-7), and in KB cells. The ovarian carcinoma cell lines included one previously established cell line (A1847) and four recent isolates obtained from the malignant ascites of patients with metastatic ovarian carcinoma (OVCAR cell lines). While all cell lines showed inhibition of protein synthesis by anti-TFR-PE, there were quantitative differences when the level of protein synthesis was assayed after a 12-hr incubation with the immunotoxin. These differences resulted from different kinetics of anti-TFR-PE activity in the various cell lines. Higher levels of cellular binding and internalization of anti-TFR were shown to contribute to increased toxicity of anti-TFR-PE. Verapamil increased the rate of protein synthesis inhibition and thus enhanced the toxicity of anti-TFR-PE in the OVCAR cell lines.     

Cell lines from human colon carcinoma with unusual cell products, double minutes, and homogeneously staining regions.

Two human colon carcinoma cell lines derived from the same tumor specimen were characterized. The cell lines, COLO 320 and COLO 321, have amine precursor uptake and decarboxylation cell properties, such as ectopic production of norepinephrine, epinephrine, serotonin, adrenocorticotropic hormone, and parathyroid hormone. The cells were morphologically different from most colon cell lines. Double minutes (DM) were initially present in nearly 100% of the metaphases. In a few subcultures of COLO 320, DM have persisted for 1.5 years. However, in COLO 321 and some subcultures of COLO 320, a loss of DM was observed and new marker chromosomes with homogeneously staining regions were observed. These unusual cell lines should be valuable for studies of apudomas of the colon and the cytogenetic phenomena of DM and homogeneously staining regions.     

Marker chromosome study of murine cell line tumor tissues

By C-method of chromosome staining three transplantable murine tumor lines passaged in vivo were studied. Marker chromosomes were discovered in all cell lines under observation. The previously described marker chromosomes B and C were found in transplantable Ehrlich ascites carcinoma cells, acrocentric chromosome with additional C-band --in cells of line C-37, acrocentric chromosome with double quantity of subcentrometric heterochromatin in cells of line TG-180. The data obtained make it possible to distinguish the lines under study by C-method of chromosome staining.     

Characterization of rat ovarian adenocarcinomas developed in response to direct instillation of 7,12-dimethylbenz[a]anthracene (DMBA) coated suture

Human ovarian cancer is predominantly of epithelial cell origin (>90% of malignant tumors) and most often presents at an advanced stage with poor prognosis. Most animal models of ovarian carcinoma yield thecal/granulosa cell tumors, rather than adenocarcinomas. Induction of adenocarcinoma in 10-45% of rats following an ovarian implantation of 7,12-dimethylbenz[a]anthracene (DMBA) coated silk suture has been reported. Here, DMBA of 99% purity was melted at 124 degrees C to impregnate a 1 cm length of sterile suture for direct ovarian implantation in Wistar Furth rats at 7 weeks of age. DMBA-treated ovaries showed a nearly complete loss of primary follicles and degeneration of granulosa cells at 16 weeks, consistent with the known toxic response of the ovary to direct DMBA application. No tumors were present. Untreated right ovaries and sham dimethyl sulfoxide-treated ovaries were normal. Ovarian tumors in DMBA-treated rats were first noted at 26 weeks post implantation reaching a cumulative tumor incidence of 77% (23/30) at 52 weeks. Controls showed no evidence of tumor at 52 weeks (0/31). Tumor histology was distributed as well differentiated adenocarcinoma (1/23), poorly differentiated adenocarcinoma (8/23), thecal/granulosa cell tumor (8/23), undifferentiated sarcoma (5/23) and one undifferentiated carcinoma with no adeno character. Tumors occasionally seeded to peritoneal mesentery, spleen and abdominal wall. Adenocarcinomas appeared to originate from the ovarian surface epithelium, with focal papillary extension into cystic space. Epithelial derived tumor cells positively react with antibodies to cytokeratin (8/8), epithelial cell adhesion molecule (Ep-CAM 5/5) and prostaglandin synthetase-1 (COX-1 4/4). Vimentin positive epithelial cells when present in adenocarcinomas (4/7), showed perinuclear staining, quite distinct from the uniformly stained stromal cells in thecal/granulosa cell tumors (8/8). The thecal/granulosa cell tumors were Ep-CAM negative (0/5) and weakly COX-1 positive (4/4). Thus, the DMBA suture model in rats yields epithelial derived tumors histologically similar to humans and should prove suitable for the testing of preventive or therapeutic agents.