Macromolecular changes accompanying immortalization and tumorigenic conversion in a human fibroblast model system

Mutagenesis of a diploid human fibroblast strain, KD, with the chemical carcinogen 4 nitroquinolin-1-oxide led to the isolation of stably immortalized neoplastic substrains. Four of these transformed strains, HuT-11, -12, -13, and -14, have been characterized in great detail with regard to morphology and changes in gene expression from the parental KD strain. The HuT-11, -12 and -13 substrains are immortalized and non-tumorigenic, in contrast to HuT-14 which is both immortalized and tumorigenic. The HuT-14 substrain expresses a defective beta-actin as a consequence of a point mutation in 1 of the 2 functional beta-actin alleles. All 4 HuT strains have induced expression of the phosphoprotein plastin and 2 EGF-related polypeptides, and down-regulated expression of the transformation-sensitive tropomyosin isoforms. KD and HuT cells expressing high levels of exogenous mutant beta-actin after gene transfection show morphological alterations. HuT-12 transfectants with excessive mutant beta-actin expression exhibit an elevated tumorigenic potential and tropomyosin-isoform switching characteristic of the tumorigenic HuT-14 strain.

Modulation of microfilament protein composition by transfected cytoskeletal actin genes

HuT-14T is a highly tumorigenic fibroblast cell line which exhibits a reduced steady-state level of beta-actin due to coding mutations in one of two beta-actin alleles. The normal rate of total actin synthesis could be restored in some clones of cells following transfection of the functional beta-actin gene but not following transfection of the functional gamma-actin gene. In gamma-actin gene-transfected substrains that have increased rates of gamma-actin synthesis, beta-actin synthesis is further reduced in a manner consistent with an autoregulatory mechanism, resulting in abnormal ratios of actin isoforms. Thus, both beta- and gamma-actin proteins can apparently regulate the synthesis of their coexpressed isoforms. In addition, decreased synthesis of normal beta-actin seems to correlate with a concomitant down-regulation of tropomyosin isoforms.

Cloning and characterization of a cDNA encoding transformation-sensitive tropomyosin isoform 3 from tumorigenic human fibroblasts

We isolated a cDNA clone from the tumorigenic human fibroblast cell line HuT-14 that contains the entire protein coding region of tropomyosin isoform 3 (Tm3) and 781 base pairs of 5'- and 3'-untranslated sequences. Tm3, despite its apparent smaller molecular weight than Tm1 in two-dimensional gels, has the same peptide length as Tm1 (284 amino acids) and shares 83% homology with Tm1. Tm3 cDNA hybridized to an abundant mRNA of 1.3 kilobases in fetal muscle and cardiac muscle, suggesting that Tm3 is related to an alpha fast-tropomyosin. The first 188 amino acids of Tm3 are identical to those of rat or rabbit skeletal muscle alpha-tropomyosin, and the last 71 amino acids differ from those of rat smooth muscle alpha-tropomyosin by only 1 residue. Tm3 therefore appears to be encoded by the same gene that encodes the fast skeletal muscle alpha-tropomyosin and the smooth muscle alpha-tropomyosin via an alternative RNA-splicing mechanism. In contrast to Tm4 and Tm5, Tm3 has a small gene family, with, at best, only one pseudogene.

A 60-kDa polypeptide in mammalian cells with epitopes related to actin

We have identified a novel actin-related 60-kDa polypeptide in mammalian cells. The relatedness of this polypeptide to actin is indicated by its affinity for DNase I, two monoclonal anti-actin antibodies, and two independent peptide-specific anti-actin antibodies which bind to actin at around amino acid 244. It is not incorporated into cytoskeletal stress fibers, although it is a stable protein. Its expression (60-kDa polypeptide, pI of 5.4 to 5.5) is inhibited by the K+ ionophore, nonactin, which is known to collapse the energy-dependent translocation of cytoplasmically synthesized proteins into mitochondria.

Internal amino acid sequence analysis of proteins separated by one- or two-dimensional gel electrophoresis after in situ protease digestion on nitrocellulose

We have developed a general two-step method for obtaining peptide fragments for sequence analysis from picomole quantities of proteins separated by gel electrophoresis. After separation by one- or two-dimensional polyacrylamide gel electrophoresis, proteins are electrophoretically transferred (electroblotted) onto nitrocellulose, the protein-containing regions are detected by reversible staining and are cut out, and each protein is digested in situ by proteolytic enzymes such as trypsin or staphylococcal V-8 protease. The resulting peptide fragments are separated by narrow-bore reverse-phase HPLC, collected, and sequenced in a gas-phase sequenator. Excellent peptide recoveries and the absence of extraneous contaminants in the separation of the peptide fragment mixture allow the generation of extensive internal sequence information from picomole amounts of protein. The method thus overcomes the problem of obtaining amino acid sequence data from N-terminally blocked proteins and provides multiple, independent stretches of sequence that can be used to generate oligonucleotide probes for molecular cloning and/or used to search sequence data bases for related proteins. This method has been successfully applied to the routine amino acid sequence analysis of a wide range of proteins isolated from one- and two-dimensional polyacrylamide gels.

A human beta-actin expression vector system directs high-level accumulation of antisense transcripts

We have constructed a mammalian expression vector consisting of 3 kilobases of the human beta-actin gene 5' flanking sequence plus 5' untranslated region and intervening sequence 1 linked at the 3' splice site to a short DNA polylinker sequence containing unique Sal I, HindIII, and BamHI restriction endonuclease sites followed by a simian virus 40 (SV40) polyadenylylation signal. Two derivatives, containing the selection markers obtained from pSV2gpt or pSV2neo, were also generated. We find that the promoter activity of this vector is a great or greater than that of the SV40 early promoter in a variety of human and rodent cells. The vector was used to generate gamma-actin and beta-tubulin antisense transcripts in human fibroblast cell lines. The antisense transcripts accumulate to levels comparable with that of the highly abundant gamma-actin and beta-tubulin mRNAs.

Expression of transfected mutant beta-actin genes: alterations of cell morphology and evidence for autoregulation in actin pools

Two different mutant human beta-actin genes have been introduced into normal diploid human (KD) fibroblasts and their immortalized derivative cell line, HuT-12, to assess the impact of an abnormal cytoskeletal protein on cellular phenotypes such as morphology, growth characteristics, and properties relating to the neoplastic phenotype. A mutant beta-actin containing a single mutation (Gly-244----Asp-244) was stable and was incorporated into cytoskeletal stress fibers. Transfected KD cells which expressed the stable mutant beta-actin in excess of normal beta-actin were morphologically altered. In contrast, a second mutant beta-actin gene containing two additional mutations (Gly-36----Glu-36 and Glu-83----Asp-83, as well as Gly-244----Asp-244) did not alter cell morphology when expressed at high levels in transfected cells, but the protein was labile and did not accumulate in stress fibers. In both KD and HuT-12 cells, endogenous beta- and gamma-actin decreased in response to high-level expression of the stable mutant beta-actin, in a manner consistent with autoregulatory feedback of actin concentrations. Since the percent decreases in the endogenous beta- and gamma-actins were equal, the ratio of net beta-actin (mutant plus normal) to gamma-actin was significantly increased in the transfected cells. Antisera capable of distinguishing the mutant from the normal epitope revealed that the mutant beta-actin accumulated in stress fibers but did not participate in the formation of the actin filament-rich perinuclear network. These observations suggest that different intracellular locations differentially incorporate actin into cytoskeletal microfilaments. The dramatic impact on cell morphology and on beta-actin/gamma-actin ratios in the transfected diploid KD cells may be related to the acquisition of some of the characteristics of cells that underwent the neoplastic transformation event that originally led to the appearance of the beta-actin mutations.

Expression of transfected mutant beta-actin genes: transitions toward the stable tumorigenic state

Mutant human beta-actin genes were introduced into normal human (KD) fibroblasts and the derivative cell line HuT-12, which is immortalized but nontumorigenic, to test their ability to promote conversion to the tumorigenic state. Transfected substrains of HuT-12 fibroblasts that expressed abundant levels of mutant beta-actin (Gly-244----Asp-244) produced subcutaneous tumors in athymic mice after long latent periods (1.5 to 3 months). However, transfected substrains of KD fibroblasts retained their normal finite life span in culture and consequently were incapable of producing tumors. Substrains of HuT-12 cells transfected with the wild-type beta-actin gene and some transfected strains that expressed low or undetectable levels of mutant beta-actin did not produce tumors. Cell lines derived from transfectant cell tumors always exhibited elevated synthesis of the mutant beta-actin, ranging from 145 to 476% of the level expressed by the transfected cells that were inoculated to form the tumor. In general, primary transfectant cells that expressed the highest levels of mutant beta-actin were more tumorigenic than strains that expressed lower levels. The tumor-derived strains were stable in tumorigenicity and produced tumors with shortened latent periods of only 2 to 4 weeks. These findings imply that the primary transfectant strains develop subpopulations of cells that are selected to form tumors because of their elevated rate of exogenous mutant beta-actin synthesis. Actin synthesis and accumulation of gamma-actin mRNA from the endogenous beta- and gamma-actin genes were diminished in tumor-derived strains, apparently to compensate for elevated mutant beta-actin synthesis and maintain the normal cellular concentration of actin. Synthesis of the transformation-sensitive tropomyosin isoforms was decreased along with mutant beta-actin expression. Such modulations in tropomyosin synthesis are characteristically seen in transformation of avian, rodent, and human fibroblasts. Our results suggest that this mutant beta-actin contributes to the neoplastic phenotype of immortalized human fibroblasts by imposing a cytoarchitectural defect and inducing abnormal expression of cytoskeletal tropomyosins.

Tropomyosin isoform switching in tumorigenic human fibroblasts

We identified six tropomyosin (Tm) isoforms in diploid human fibroblasts. We used computerized microdensitometry of 2-dimensional protein profiles to measure the relative rates of synthesis and abundance of the individual Tm isoforms and actin, the two major structural constituents of microfilaments. In carcinogen-transformed human fibroblasts (HuT-14), the rates of synthesis of three Tm isoforms (Tm1, Tm2, and Tm6) were greatly decreased relative to normal diploid parental fibroblasts and to actin. In contrast, related nontumorigenic HuT fibroblasts which are "immortalized" and anchorage independent exhibited both slight down-regulation of Tm1 and Tm6 and 3.5-fold up-regulation of Tm3. Thus, Tm isoform switching from the predominance of the larger more avid Tm isoforms (Tm1, Tm2, Tm3, and Tm6) to the smaller, less avid Tm isoforms (Tm4 and Tm5) in microfilaments was a transformation-induced change correlated with tumorigenicity in human fibroblasts.

Abundant synthesis of the transformation-induced protein of neoplastic human fibroblasts, plastin, in normal lymphocytes

The transformation-induced protein plastin (p219; Mr 68,000, pl 5.3) is a reliable cytosolic marker for neoplastic human fibroblasts. Fibroblasts transformed in vitro by chemical carcinogens or SV40 virus and tumor-derived cancer cells of fibroblastoid or epithelioid origin usually express plastin and p220, a minor phosphorylated form of plastin. We report here that plastin is expressed as one of the most abundant proteins of normal, untransformed lymphocytes. The phosphorylated form of plastin was detectable in adherent monocytes but not in purified T- or NK lymphocytes. We also demonstrate that an allelic variant or mutated form of plastin exhibiting altered charge is found at a reduced frequency in the human population. We discuss the possible significance of these observations in terms of evaluating the role of plastin induction in expression of the cancerous phenotype of fibroblasts.

Pulfrich stereo-illusion phenomenon in serous sensory retinal detachment of the macula

Four patients (three men, 68, 35, and 33 years old, and one woman, 46 years old) had central serous elevation of the macula with abnormal latency of the visual-evoked potential and spontaneous Pulfrich phenomenon. In three instances both the electrophysiologic test and the clinical Pulfrich test reverted to normal on resolution of the retinopathy. This correlated with normalization of visual-evoked potential latency in the affected eye.

Identification and order of sequential mutations in beta-actin genes isolated from increasingly tumorigenic human fibroblast strains

We have sequenced the mutant beta-actin gene of a tumorigenic human fibroblast cell line (HuT-14T) and found that it carries three mutations that alter the amino acids at positions 36, 83, and 244 as well as a 22-base-pair "insertion" sequence, in the 5' intron, not present in a wild-type gene. The less tumorigenic cell line HuT-14, a progenitor of HuT-14T, has the same codon-244 mutation and the insertion sequence but not the other two mutations. A nontumorigenic cell line that is related to HuT-14 but that has no beta-actin mutations does carry the intron-length polymorphism. We conclude that the mutation at codon 244 occurred first in a beta-actin allele already bearing the 22-base-pair intron insert and that mutations at codons 36 and 83 arose subsequently during the selection for the HuT-14T phenotype. Rat-2 cells synthesize the appropriate charge-variant species of mutant actin protein when transfected with either the singly or the triply mutated beta-actin gene.

Evolution of the functional human beta-actin gene and its multi-pseudogene family: conservation of noncoding regions and chromosomal dispersion of pseudogenes

We have assigned six members of the human beta-actin multigene family to specific human chromosomes. The functional gene, ACTB, is located on human chromosome 7, and the other assigned beta-actin-related sequences are dispersed over at least four different chromosomes including one locus assigned to the X chromosome. Using intervening sequence probes, we showed that the functional gene is single copy and that all of the other beta-actin related sequences are recently generated in evolution and are probably processed pseudogenes. The entire nucleotide sequence of the functional gene has been determined and is identical to cDNA clones in the coding and 5' untranslated regions. We have previously reported that the 3' untranslated region is well conserved between humans and rats (Ponte et al., Nucleic Acids Res. 12:1687-1696, 1984). Now we report that four additional noncoding regions are evolutionarily conserved, including segments of the 5' flanking region, 5' untranslated region, and, surprisingly, intervening sequences I and III. These conserved sequences, especially those found in the introns, suggest a role for internal sequences in the regulation of beta-actin gene expression.

Smooth muscle alpha-action is a transformation-sensitive marker for mouse NIH 3T3 and Rat-2 cells

Heteroploid mouse NIH 3T3 fibroblasts and several rat fibroblast strains (Rat-1, Rat-2 and REF-52) are cell lines of special interest in the field of carcinogenesis because of their extensive use as normal cells in transformation assays for putative cancer-causing genes. Exposure of these cells to carcinogenic chemicals or oncogenic DNA produces anchorage-independent cells with retracted cytoplasms that lack actin cables. All human fibroblast strains, normal and transformed, synthesize two electrophoretic forms of actin (beta- and gamma-actin). In contrast, we discovered that early-passage mouse and rat strains synthesize abundant amounts of each of the three electrophoretic forms of actin (alpha-, beta- and gamma-actin) but mouse and rat cancer cells express only beta- and gamma-actins. We now show that in NIH 3T3 and Rat-2 fibroblasts a third actin, the smooth muscle alpha isoform, is abundantly co-expressed with beta- and gamma-actin. In every instance tested following transformation to tumorigenicity, the accumulation of alpha-actin messenger RNA and alpha-actin synthesis was greatly inhibited. Shutdown of alpha-actin expression thus appears to be a reproducible transformation-sensitive marker in rodent fibroblasts.

Expression of neoplasia-related proteins of chemically transformed HuT fibroblasts in human osteosarcoma HOS fibroblasts and modulation of actin expression upon elevation of tumorigenic potential

Two sets of abundant cytoplasmic transformation-specific polypeptides, p788/p789 and p219/p220, have been identified by comparing in vitro-transformed human fibroblasts with diploid human fibroblasts. These polypeptides are also expressed by the human fibrosarcoma and osteosarcoma cell lines HT1080 the human fibrosarcoma and osteosarcoma cell lines HT1080 and HOS, respectively. HOS cells, however, synthesize only one of the two electrophoretic forms of each marker set, p789 and p219, at greatly reduced rates compared to the rates of synthesis found for HT1080 cells and the in vitro-transformed cell lines. Induction of expression of these neoplastic marker polypeptides is independent of the activation of a transforming gene that will induce focus formation in confluent mouse 3T3 cell monolayers. Activation of the met oncogene in MNNG-HOS cells and simultaneous elevation of tumorigenic potential did not lead to a significant change in the rate of the 600 most abundant polypeptide species with the exception of one of the two cytoplasmic actin polypeptides. While the normal ratio of beta-to gamma-actin which is approximately 2:1 was expressed in "untransformed" HOS cells, MNNG-HOS cells synthesized 50% less beta-actin resulting in a 1:1 ratio of beta-actin to gamma-actin. Our finding here, together with our previous characterization of the human beta-actin gene, leads us to predict that one of two functional beta-actin genes expressed in HOS cells has been inactivated in MNNG-HOS cells by either a regulatory or structural gene mutation.

Identification of polypeptides on two-dimensional electrophoresis gels by amino acid composition

We present a method that can, in principle, provide tentative identification of a substantial proportion of the polypeptides resolvable on a given two-dimensional electrophoresis gel. Computerized microdensitometry of autoradiograms from 20 gels labeled in turn with each of the 20 common amino acids provides the data for simultaneously measuring the amino acid composition of all polypeptides of interest on the gel. These compositions are then compared with computer data bases of known protein compositions. Similarity between a known and an unknown polypeptide with comparable molecular mass indicates a potential identification, which can then be confirmed with conventional techniques. We illustrate this technique by applying it to the identification of proteins in a transformed human cell line (HuT-14).

Identification of polypeptides on two-dimensional electrophoresis gels by amino acid composition

We present a method that can, in principle, provide tentative identification of a substantial proportion of the polypeptides resolvable on a given two-dimensional electrophoresis gel. Computerized microdensitometry of autoradiograms from 20 gels labeled in turn with each of the 20 common amino acids provides the data for simultaneously measuring the amino acid composition of all polypeptides of interest on the gel. These compositions are then compared with computer data bases of known protein compositions. Similarity between a known and an unknown polypeptide with comparable molecular mass indicates a potential identification, which can then be confirmed with conventional techniques. We illustrate this technique by applying it to the identification of proteins in a transformed human cell line (HuT-14).

Molecular cloning and characterization of mutant and wild-type human beta-actin genes

There are more than 20 beta-actin-specific sequences in the human genome, many of which are pseudogenes. To facilitate the isolation of potentially functional beta-actin genes, we used the new method of B. Seed (Nucleic Acids Res. 11:2427-2446, 1983) for selecting genomic clones by homologous recombination. A derivative of the pi VX miniplasmid, pi AN7 beta 1, was constructed by insertion of the 600-base-pair 3' untranslated region of the beta-actin mRNA expressed in human fibroblasts. Five clones containing beta-actin sequences were selected from an amplified human fetal gene library by homologous recombination between library phage and the miniplasmid. One of these clones contained a complete beta-actin gene with a coding sequence identical to that determined for the mRNA of human fibroblasts. A DNA fragment consisting of mostly intervening sequences from this gene was then used to identify 13 independent recombinant copies of the analogous gene from two specially constructed gene libraries, each containing one of the two types of mutant beta-actin genes found in a line of neoplastic human fibroblasts. The amino acid and nucleotide sequences encoded by the unmutated gene predict that a guanine-to-adenine transition is responsible for the glycine-to-aspartic acid mutation at codon 244 and would also result in the loss of a HaeIII site. Detection of this HaeIII polymorphism among the fibroblast-derived clones verified the identity of the beta-actin gene expressed in human fibroblasts.

Neoplastic human fibroblast proteins are related to epidermal growth factor precursor

We report the amino acid composition of two polypeptides, p788 and p789. These polypeptides are reliable markers for neoplastic transformation in human fibroblasts. Their compositions are unusually rich in cysteine and serine. Because the recently reported amino acid sequence of mouse epidermal growth factor precursor (prepro-EGF) is also rich in those two amino acids and because the role of p788 and p789 as markers for neoplastic transformation is consistent with the fact that epidermal growth factor has been shown to play some role in transformation, we investigated the hypothesis that p788 and p789 are related to prepro-EGF. We compared the amino acid composition of p788 with that of all possible interior domains of prepro-EGF of appropriate length. We found that the composition of p788 is remarkably similar to that of residues 630-880 of prepro-EGF. The similarity is sufficiently strong to support the conclusion that it reflects amino acid sequence homology.

Limitations of the brief form of the Halstead Category Test

This study attempted to cross-validate a short form of the Category Test (subtests 1-4) first used by Calsyn, O'Leary, and Chaney (1980). One hundred and sixty-eight subjects were assigned to one of six neurological categories, and Category Test scores predicted (via regression analysis) from performance on the short form were compared with actual scores obtained from the original long form. While there was a high correlation (r = .91) between the two sets of scores, a large number of normal subjects were misclassified as brain-damaged. Additionally, subjects with focal right lesions could not be differentiated from normals either on the basis of error scores predicted from short form performance or the absolute number of errors made on subtests 1-4. These results suggested that shortening the Category Test may limit its applicability with certain populations.

A mutation in actin associated with neoplastic transformation

A new protein was recognized in a chemically transformed human fibroblast cell line when its proteins labeled with [35S]methionine were compared with those from normal human fibroblasts by two-dimensional gel electrophoresis. The new protein was found in the Triton-insoluble cytoskeletal fraction as well as in the Triton-soluble fraction, and it migrated very closely to beta- and gamma-actins on the gels. This new protein was identified as a variant form of actin by its reaction with antiactin antibody and its tryptic peptide pattern, which was identical to actin. mRNA coding for the variant actin was detected only in this particular transformed line. The size and cross- hybridizability with Dictyostelium actin cDNA of mRNA coding for the variant actin and complete amino acid sequence of the variant actin indicate that the new variant actin is the product of a mutated beta-actin gene. Only a single amino acid (glycine) at position 244 was replaced by aspartic acid. This substitution corresponds to a GC----AT transition, a point mutation. On the other hand, a highly malignant cell variant was isolated from the transformed line. The mutated beta-actin was further altered in this highly malignant subclone: it showed a more negative charge, rapid synthetic rate, and a short half-life in the cells. Incorporation into the cytoskeleton was significantly reduced in the mutated beta-actin. A hypothesis on the relationship between a mutation in the actin gene and oncogenic transformation was proposed.

Tumorigenic potential of human fibroblasts as a function of ability to express a novel form of influenza A nucleocapsid protein

Influenza A virus released by infected diploid human fibroblasts contains nearly equal amounts of two electrophoretic forms of the viral nucleocapsid protein NP (NP1 and NP2). Pulse-chase labeling and tryptic fingerprinting of NP1 and NP2 have suggested that NP1 is converted to NP2 late in the lytic cycle as a consequence of a post-translational proteolytic event. Within normal fibroblasts only one cellular form of NP (NP1) is detectable indicating that synthesis of NP2 is associated only with the release of virus from these normal cells. Four neoplastic substrains derived from the normal fibroblast strain exhibit varying degrees of neoplastic character in vitro and tumorigenic potential in athymic mice. This family of human fibroblast strains can be divided into three orders of tumorigenic potential: (i) normal and non-tumorigenic; (ii) neoplastic but rarely tumorigenic; and (iii) neoplastic and always tumorigenic. In contrast to the parental non-tumorigenic cell type which exhibits no cellular NP2, the two classes of neoplastic fibroblasts exhibit NP2 at abundance levels which appear to reflect the two elevated degrees of tumorigenic potential. Thus, assessment of influenza A gene expression may have detected a novel cellular protease which is incrementally elevated along with tumorigenic potential of this human fibroblast family.

Skin tags: a cutaneous marker for colonic polyps

The relation between adenomatous colonic polyps and the development of adenocarcinoma of the colon is well established. An association between skin tags and colonic polyps in patients with acromegaly has also been reported. To ascertain if skin tags are a cutaneous marker for colonic polyps independent of the presence of acromegaly, 100 men referred for colonoscopy were studied. Forty-six patients had colonic polyps and 37 also had skin tags; the correlation was highly significant (p less than 0.005). The sensitivity and specificity of the presence of skin tags serving as a cutaneous marker for adenomatous colonic polyps were both greater than 75%. Thus, at least in this population, skin tags may serve as a means for identifying patients at increased risk for having colonic polyps.

A randomized prospective study of vindesine versus doxorubicin and cyclophosphamide in the treatment of epidermoid lung cancer

A randomized prospective study was conducted comparing vindesine (VDS) with doxorubicin and cyclophosphamide (D/C) in the treatment of advanced squamous cell carcinoma of the lung. No patient had a complete response. Seven of 28 (25%) patients had partial response (PR) to VDS while one of 19 (5%) had a PR to D/C (P less than 0.08). Adding PR plus minor response (MR), ten of 28 (36%) patients responded to VDS while two of 19 (11%) responded to D/C (P less than 0.05). Median survival was improved among patients showing PR and MR over those not responding (P less than 0.05). This study concludes, VDS is an active agent in the treatment of squamous cell carcinoma of the lung and should be considered for combination chemotherapy and adjuvant trials. VDS toxicity appears acceptable with six weekly doses of 3 mg/m2. The benefit of a maintenance schedule could not be demonstrated.