Delivery of aclacinomycin A to human glioma cells in vitro by the low-density lipoprotein pathway

The present study shows that a human malignant glioma cell line (U-251 MG) accumulates and degrades low-density lipoprotein (LDL) by a saturable, high-affinity process (Km approximately equal to 5 micrograms/ml). Accumulation and degradation could be enhanced by preincubating the cells in a lipoprotein-deficient medium. The LDL degradation rate was highest when the cells were proliferating rapidly. An aclacinomycin A:LDL complex containing 150 to 450 drug molecules per LDL particle could be obtained by incubating LDL with a large excess of aclacinomycin A at 40 degrees. When the glioma cells were incubated with the aclacinomycin A:LDL complex, cellular drug accumulation was dependent on the LDL receptor activity. There are four reasons for drawing this conclusion. (a) U-251 MG cells with high LDL receptor activity accumulated more drug than U-251 MG cells with low LDL receptor activity. (b) U-251 MG cells accumulated more drug than a mutant fibroblast line (GM 1915) lacking LDL receptor activity. (c) Aclacinomycin A accumulation was increased when U-251 MG cells were incubated in the presence of chloroquine, an agent that inhibits LDL degradation. (d) Aclacinomycin A accumulation was reduced when U-251 MG cells were incubated in the presence of either an excess of native LDL or heparin, which has been demonstrated to inhibit receptor-mediated binding and degradation of LDL. The aclacinomycin A:LDL complex also inhibited growth of the glioma cells. Our results suggest that the glioma cells studied have LDL receptors and that it may be possible to use LDL as a vehicle for lipophilic antineoplastic drugs in order to increase the drug accumulation in tumor cell populations with high LDL receptor activity.

The effect of systemic human interferon-alpha administration to patients with glioblastoma multiforme

This report presents the results of a phase I trial of the value of human leucocyte interferon-alpha in the treatment of glioblastoma. Twelve patients entered the trial. In one case we believe that the patient benefitted from the interferon treatment. CT scans of patients on interferon did not reveal the true extent of the tumorous tissue.

Monoclonal antibodies to glial fibrillary acidic protein. 1. Characterization

Mouse hybridomas producing antibodies to glial fibrillary acidic protein (GFAP) have been cloned and their immunoglobulins characterized biochemically, immunochemically and immunocytochemically. Immunoaffinity columns were prepared using cyanogen bromide activated sepharose 4R and the antibodies of the C9 clone. A protein giving a single band in the 50-55 kd range was thus isolated from aqueous extracts of bovine brain. The clone yields antibodies which are, on the basis of these studies, specific for GFAP. The antibody belongs to the class IgG1 and has been applied to human tissues, both frozen sections and sections embedded in paraffin wax following fixation in formaldehyde. The results show that the antibody may be of assistance in the classification of human brain tumors.

Formation and growth of multicellular spheroids of human origin

Different types of human cells which normally grow as monolayers or suspension cultures were tested for their capacity to form and grow as spheroids. Sixteen out of the 27 tested tumour cell lines formed spheroids. Nearly all of these spheroids also grew. With only two exceptions the doubling times were longer when the tumour cells grew as spheroids than when they grew in conventional mass culture. Eleven out of 13 tested human non-tumour cells formed small spheroids but of these only the spheroids of lymphoid origin could grow. These lymphoid cells grew faster when aggregated to spheroids than when in single-cell suspension culture. None of the other non-tumour cells, which normally grew as monolayers, could grow as spheroids. The normally monolayer-cultured tumour cells formed symmetrical spheroids with smooth surfaces while the normally suspension-cultured cells formed irregular spheroids with rough surfaces. All large spheroids had a necrotic centre surrounded by a shell of viable cells. The thickness of the viable cell layer varied depending on cell type. The shape and organization of cells within the spheroids also varied largely. The results show that many types of human cells can be cultured as spheroids and that a wide spectrum of morphological appearances and growth rates can be obtained.

A versatile localization system for microscopic multiparametric analysis of cells

A new, simple and relatively inexpensive electronic digital position readout (DPRO) system which can be applied to the rapid localization and recovery of microscopic material is described. It is based upon a commercially available digital position readout system which is routinely utilized by industry for small machine tools and measuring equipment. This has been mounted onto the stage of various microscopic instrumentation to provide X and Y coordinates relative to an arbitrary reference point. The integration of small computers interfaced to scanning interferometric, microdensitometric and fluorescence microscopes were used to demonstrate the reliability, versatility and ease of application of this system to problems of multiparametric measurements and analysis of cultured cells. The system may be expanded and applied to clinical material to obtain automatized, multiparametric measurements of cells in haematology and clinical cytology.

An approach to the assessment of membrane stability of cultured cells

A simple method for assessing the combined stability of the plasma and lysosomal membranes of cultured cells is described. Monolayers of normal, human glial cells were incubated in situ in an isotonic, buffered sucrose solution (pH 5.0) containing the acid phosphatase (AP) enzyme substrate p-nitrophenyl phosphate (PNPP). The rate of appearance, in the solution, of the reaction product p-nitrophenol (PNP) was measured spectrophotometrically, curves then plotted, and fitted by computer. "Lag time" (LT) was calculated, and an index of membrane lability constructed, termed "fragility index" (FI). Transmission electron microscopy (TEM), "vital" staining of the cells with fluorescein diacetate (FDA) and Evans Blue (EB), and use of a Gomori-type cytochemical technique, indicate that the data reflects the combined stability of lysosomal and plasma membranes. The latter playing the more critical role. Cell cultures pre-incubated with various membrane labilizing or stabilizing agents were compared. Control, 0.3 M sucrose, and normal saline treated cells demonstrated similar stability. Distilled water decreased AP latency (increased fragility), and the magnitude of this effect was time dependent. Cells fixed in glutaraldehyde (GA) retained much of their osmotic reactivity, as confirmed by distilled water treatment. Oxygen derived free radicals caused pronounced fragility, while dexamethasone, a membrane stabilizing agent, decreased membrane fragility. Triton X-100 abolished latency completely, and total AP activity was very rapidly recovered outside the cells in the surrounding incubation medium. These results suggest this technique yields a measure of membrane stability which is sensitive enough to differentiate between known stabilizers and labilizers of membranes. Hence, this may prove an easy and useful aid for the assessment of how various substances and environments modulate the lysosomal and plasma membrane stability of cultured cells.

Scanning and transmission electron microscopy following irradiation of Ehrlich ascites tumour cells. Relationships to cell cycle

Following irradiation with 5 Gy, Ehrlich ascites tumour cells growing in vivo were separated by means of elutriator centrifugation into G1, S-phase and G2 + M cells. The surface and internal morphology of the cells was analysed using scanning and transmission electron microscopy and compared with non-irradiated controls. Marked changes of the cell surface were found 5 to 72 h after irradiation, with the development of long straight microvilli mainly in S-phase and G2 cells and the appearance of cells without microvilli in G1. The latter were generally associated with intracellular degenerative changes. The appearance of these microvilli, and the consequent increase in cellular surface area was correlated to enlargement of the Golgi complex. Changes in the distribution of intracellular organelles were noted 5 h after irradiation in cells from all stages of the cell cycle. An increase of the ratio of polyribosomes to ribosomes was found in S-phase and G2 cells up to 72 h. The appearance of long microvilli was not related to a redistribution of cells in cell cycle and occurred below doses at which changes in cell membrane function are usually found.

The fixation, dehydration, drying and coating of cultured cells of SEM

Cultivated cells form a valuable model system for studies on the effects of various preparative protocols for scanning electron microscopy (SEM). The various effects of each preparative step can be followed in detail in the light microscope and no diffusion gradients complicate the fixation and other procedures as in the case of solid tissues. Studies on cultivated cells indicate that the glutaraldehyde component of a glutaraldehyde-based fixative does not contribute to the effective osmotic pressure of the fixative and thus the osmolarity of the buffer, and other components, must be equalized to that of the medium in which the cells grow. Even small deviations from this ideal effective osmotic pressure will result in osmotically induced artefacts. Disturbances of pH and temperature of the cultures prior to and during fixation will result in changes in the appearance of many cellular structures such as microspikes and ruffles. We find that osmium fixation is advisable in most instances for best possible membrance preservation and that even long periods of glutaraldehyde fixation do not compensate for osmium fixation. Dehydration always results in shrinkage. Freeze drying (FD) and critical point drying (CPD) also give rise to shrinkage, the former to a lesser degree than the latter. A gold-palladium alloy gives a less granular coating that does gold alone. When cultured cells are studied, a metal thickness of between 5 and 15 nm is usually sufficient to give rise to an adequate secondary electron production and to avoid charging even at accelerating voltages of 30-40 kV. Without treatment with OsO4 a thicker metal coating is required.

Mixed adenosquamous carcinoma of the cecum: report of a case and review of the literature

A case of mixed adenocarcinomatous and squamous carcinomatous tumor of the cecum is reported. The squamous elements present in the tumor had all the criteria of malignancy and not of simple squamous metaplasia (as in adenoacanthoma). The term mixed adenosquamous carcinoma should therefore connote such a tumor.

Tumor classification by electron microscopy of fine needle aspiration biopsy material

The application of fine needle aspiration biopsy cytology to tumor diagnosis and classification is gaining increased acceptance. The classification of some poorly differentiated tumors may prove particularly difficult for the cytologist as well as for the pathologist. In such cases electron microscopic examination of fine needle aspiration biopsy material can be of great assistance. A simple, yet dependable, technique is described for the study of such material. The method has been shown to be of decisive importance in the classification of 80% of a selected series of cases submitted to ultrastructural analysis. Using this method, a preoperative diagnosis can be obtained in otherwise equivocal cases.

The fine structure of "dividers" and "non-dividers" in phase II human glial cell cultures

A method is described which allows a comparison in the transmission electron microscope (TEM) of cells with different remaining proliferative capacity from one and the same culture. The method takes advantage of a mini-cloning technique employing hapatotactic palladium islands in combination with micro-dissection and preparation for TEM of islands carrying various numbers of cells after 10 days in culture, when all miniclones have become density dependent growth inhibited. By means of this technique non-dividers were compared with miniclones of dividers composed of five to eight cells originating from single cells. Moreover, large, immotile cells without peripheral ruffling activity, known to be non-dividers, were compared with small, ruffling cells, known to be dividers, in the reflection-interference mode in sparse cultures of living cells, and in the TEM mode as whole cell preparations after critical point drying of cells cultured on formvar-coated, gold EM-grids. Non-dividers proved to contain a moderate number of residual bodies, well developed Golgi areas, and often branched or circular mitochondria; they were thinly spread over the substratum with many focal points of contact, and large areas of close apposition between cell and substratum.

DNA distribution in various parts of malignant gliomas assayed on stereotactic biopsies

The study concerns the relation between the computerized tomogram, histopathology and DNA distribution in gliomas. The investigation was performed on stereotactic biopsies, which enabled the comparison to be made on a point-to-point basis. No clear-cut relation was found between histopathological grading and DNA distribution. In 1 patient diploid and aneuploid tissue was found in different parts of the tumor. In this case the difference in ploidy was mirrored by differences in histopathological grading and gross morphology as indicated by the CT scan.

Stereotactic biopsy in acoustic tumors

5 cases of tumors of the cerebellopontine angle were subjected to stereotactic puncture and biopsy for various reasons (preoperative differential diagnostic difficulties, cyst evacuation, evaluation of the effect of stereotactic radiosurgery). Material for cytology was aspirated in all 5 cases; in addition, a spiral biopsy was obtained in 2. The specimens enabled a satisfactory morphological judgement in 4 cases, while in 1 case the emptying of a cyst did not provide adequate material. No untoward effects were observed.

Ultrastructural features of cultured human glia and glioma cells

The fine structure of three lines of human normal glial cells and eight established lines of malignant glioma cells are described. The glial cell lines were ultrastructurally very similar whereas the glioma cell lines differed greatly from one another. In sparse proliferating cultures there were no consistent findings which distinguished the glioma cell lines as a group from the normal glial cells. Only in post-confluent cultures could the consistently irregular cell surfaces and ruffling, both at the cell periphery and centrally on the upper cell surface, with associated pinocytosis, distinguish the glioma from the post-confluent glial cultures, which did not possess these properties. The common attributes of post-confluent glioma cells reflect the cells' continued proliferation. The glioma lines did display individual ultrastructural characteristics which appear to be stable, the glioma lines having retained these during a number of years of continual passage.

The fine structure of growing human glia and glioma cells. Whole cell preparations

Three lines of normal human glia cells and eight established lines of malignant glioma cells have been studied in the electron microscope (E.M.), using preparations of critical-point dried whole cells, sparsely grown on formvar-coated, E. M., gold grids. The malignant cell lines showed a very varied morphology, almost every line having its peculiarities as compared to the essentially identical normal glia lines. The major differences noted concerned the form of the leading lamellae, number of microspikes and the distribution of organelles such as secondary lysosomes and mitochondria. No single consistent finding made it possible to differentiate the glioma cells as a group from the glia cells in sparse cultures. The findings of this study show some of the individual glioma cell lines to have characteristic cell-surface structures. They were found to be identical with the findings in previous SEM studies, suggesting the peculiarities of the individual malignant glioma lines to be stable and retained, despite continual passage.

The fine structure of growing and non-growing whole glia cell preparations

Human glia cells become blocked in G1 if starved of serum. The characteristics of the GI blocked state are flattening on the substrate, and absence of cell translocation, ruffling and macropinocytosis. Re-entry into the cell cycle, as a result of growth factor stimulation, is accompained and even preceded by the return of this cellular locomotion. We have studied the fine structure of intact human glia cells and ultrathin sections of these cells when proliferating normally in vitro, when starved of serum and during their return to the cell cycle following stimulation with mEGF (mouse epidermal growth factor). Particular attention was paid to morphologically definable components of the cellular musculoskeletal system. Proliferating interphase glia generally had a leading lamella containing few organelles and oriented bundles of 7 nm microfilaments with structureless lamellipodia at their tips, which often formed ruffles. The perinuclear area was thick and contained many cell organelles, including mitochondria and secondary lysosomes. Glia starved of serum were thinly spread; their peripheral cytoplasm was filled with a diffuse mat of microfilaments, they had no structureless lamellipodia and their perinuclear areas, although thinner, contained cell organelles in equal amounts and of similar type of those found in proliferating cells. On EGF stimulation, after approximately 2 hours the perinuclear area of the cells thickened, and structureless lamellipodia subsequently appeared at the tips of the leading lamellae, forming ruffles. The cells finally began to translocate, the process being accompained by the reorientation and packing of the microfilaments into bundles. As the kinetics of EGF binding and break down by glia cells are similar to those described for fibroblasts, the findings do not support the concept of EGF receptor interactions inducing ultrastructurally demonstrable microfilament or other musculoskeletal structural changes in the cell. They do, however, define the differing cellular morphologies of motile and immobile structures.

Stereotactic computer tomography for biopsy of gliomas

A technique is introduced enabling automatic transfer of coordinates obtained at computer tomography into a stereotactic system previously applied in biopsies of brain lesions. Four to five biopsies from different parts of gliomas were taken to compare the structures demonstrated on computer tomography with the microscopic appearances. Of 45 biopsies in 13 patients, 36 were predicted correctly. This also served as an attempt to classify gliomas on the basis of their appearance in the CT image.

Stereotactic biopsies and computer tomography in gliomas

This study was carried out in order to obtain data on the relation between tumour structures seen in computer tomograms and the corresponding histopathology and cytology. Nine consecutive patients were studied, and stereotactic biopsies were obtained from sites determined on contrast enhanced computer tomograms. Biopsies were obtained from tumour areas with high and low contrast uptake and from the low attenuating areas surrounding the tumours. The results indicated a close correlation between the microscopical morphology of gliomas and the pattern of the computer tomogram. Biopsy samples from low-uptake central areas contained tumour tissues, necrotic tissue, and in one case a cyst. Biopsies from high-uptake areas typically contained tumour tissue, whereas biopsies from low-uptake surrounding areas contained oedematous non-tumour tissue. For tumour diagnosis biopsies should be obtained from both low and high attenuating tumour areas.

A comparison of the effects of three widely used glutaraldehyde fixatives on cellular volume and structure. A TEM, SEM, Volumetric and Cytochemical Study

The effects of three widely used glutaraldehyde-based fixatives on cellular volume and structure have been studied utilizing TEM, SEM, time-lapse micrography during the fixation procedure, volumetry and demonstration of the lysosomal enzyme acid phosphatase. The cells used were in vitro cultivated human glia and glioma cells and suspensions of isolated rat liver parenchymal cells. The fixatives compared were the following: 2 per cent glutaraldehyde (GA) in 0.1 M Na-cacodylate-HCL buffer (cac) with 0.1 M sucrose (pH 7.2); total osmolality (T) 510 mOsmol; vehicle osmolality (V) 300 mOsm, 2 per cent GA in 0.1 M cac (pH 7.2; T = 410 mOsmol; V = 200 mOsmol) and 1.5 per cent GA in 0.067 M cac with 0.033 M sucrose (pH 7.2; T = 320 mOsmol; V = 170 mOsmol). It was found that the fixative with a vehicle osmolality of 300 mOsmol gave results which were interpreted as ideal while the two fixatives were hypotonic vehicles resulted in changes which were easily demonstrated during volumetry, time-lapse micrography, SEM and cytochemistry. However, the differences observed in the TEM were less obvious and difficult to interpret, the major alternations being changes in the configuration of the ER in the liver cells. In conclusion, our findings show that even small variations in the composition of a glutaraldehyde fixative can result in structural changes which do not correspond to the functional morphology of a living cell. Such changes make correct interpretation of micrographs difficult.

Fibrinolytic activity of in vitro cultivated human bladder cell lines

Three human bladder carcinoma cell lines, T 24, RT 4, and MANO, a human bladder nonmalignant epithelial cell line, HCV-29, and a human lung fibroblast line, 460 H1, were investigated for their ability to induce fibrinolytic, urokinase and plasmin inhibitory activities in cell culture, using serum-free medium, for up to 36 h. Generally, the non-malignant cell line and the fibroblast line had a greater ability to produce urokinase inhibitor than did the malignant cell lines. The amount produced varied greatly between cells and over the study period. A low concentration of plasminogen activator, immunologically identical with urokinase, and its accumulation in culture supernate were found with RT 4 after 12 h and 24 h cultivations, whereas no plasminogen activator was detected in all other cell lines for periods up to 36 h. No plasmin, non-specific protease or plasmin inhibitory activities were detected in any of the supernates from the cell lines.