Gisela Haemmerli

Cell-to-substrate adhesions during spreading and locomotion of carcinoma cells: A study by microcinematography and reflection contrast microscopy☆

Abstract Motility and patterns of adhesion were determined by time-lapse cinematography and reflection contrast microscopy for two types of carcinoma cells, selected for their different motile behavior and not for their malignancy. Cells from the V2 rabbit carcinoma become locomotory soon after having established the necessary contact to the substratum. In contrast, cells from a human epidermoid carcinoma (LICR-OC-1) first attain a fully spread configuration before some cells slightly round up again for a slow locomotory activity of short range and duration. Reflection contrast showed that during spreading and locomotion, the cells from both carcinomas displayed a predominance of grey, the color associated with close contacts. Fully spread cells, on the other hand, presented a multitude of focal contacts in individually different arrangements of black streaks and dots, randomly distributed over the entire cell area. The functional meaning of this heterogeneity in the arrangement of focal contacts in fully spread cells is not yet understood. The importance of close contacts for spreading and locomotion, however, seems to be established and is in agreement with findings reported for other cell types engaged in the same activities. It is therefore suggested that the formation of substrate contacts depends on cellular activity rather than on the cell type.

Cytoskeletal organization in locomoting cells of the V2 rabbit carcinoma

The relationship between the organization of cytoskeletal elements and locomotory activity was studied in single cells of the V2 rabbit carcinoma. Like migratory fibroblasts, and unlike colony-forming epithelial cells, these cells show a pronounced horizontal polarization, and develop a large lamella at their leading front. With affinity-purified antibodies and a combination of light and electron microscopic techniques, actin and alpha-actinin (but not myosin and tropomyosin) were found highly concentrated within the marginal region of the leading lamella, both in ruffles and in the underlying zone of contacts with the substratum. Close contacts prevailed in the locomotory cells and small focal contacts developed only in cells detaching from others. Focal contacts always contained small microfilament bundles. Reorganization of actin filaments is suggested as the fundamental event for the dynamic contact formation of the leading lamella. Large microfilament bundles (stress fibers) were absent in all stages of locomotion. Since locomotory behavior and shape changes of V2 cells are the same on glass as on the surface of a natural membrane, the rabbit mesentery, organization and distribution of contractile elements of cultured V2 cells probably reflect the in vivo situation.

Different modes of mesenteric infiltration displayed by two rat leukemias. A study by scanning and transmission electron microscopy and by microcinematography.

SummaryInfiltration of the mesentery after intraperitoneal implantation of two transplantable rat leukemias, the undifferentiated L5222 and the myeloid BNML, was studied by means of scanning and transmission electron microscopy, and microcinematography. In animals implanted with L5222 cells, contraction of the mesenteric mesothelium is a conspicuous feature. It occurs within the first 24 h after implantation and influences decisively the course of infiltration. In contrast, the presence of BNML cells leads to mesothelial contraction only in the terminal stage and, therefore, exerts no direct effect on infiltration. In addition, the two leukemias differ with regard to their cellular motility. Whereas L5222 cells locomote within the mesentery, only stationary movements are recorded with BNML cells. Based on the different interactions with the mesothelium and cell motilities, two distinct modes of infiltrating the mesentery could be ascertained for the two rat leukemias.

Motility of l5222 rat leukemia cells.

SummaryThe locomotive behavior of cells of the transplantable rat leukemia L5222 was studied by means of microcinematography. It was found that these cells exhibit a homogeneous pattern of movement resembling that of normal lymphoblasts and stimulated lymphocytes. This is in contrast to cytochemical and ultrastructural evidence according to which the cells are completely undifferentiated. Another phenomenon, recorded by timelapse, is the ability of the cells to move in a spherical and in a flattened state. Treatment with cytochalasin B in a concentration of 30μg/ml leads to loss of locomotion. Incubation with colchicine, 40μg/ml, results in a greatly reduced locomotion, while the on-spot motility is not impaired. The suitability of this model for investigations on the role of locomotion in penetration and tumor cell dissemination is emphasized.

Motility and cytoplasmic filamentous structures of L5222 and BNML leukemia cells

Abstract Results of our studies on motility and cytoplasmic filamentous structures in cells of the two leukemias can be summarized as follows: L5222 cells are predominantly locomotive, BNML cells show mainly on spot motility. While the arrangement of microfilaments and microtubules is similar in the two populations, that of 100-A filaments is different: There is a large amount of these filaments in L5222 cells, and a small amount in BNML cells. L5222 cells further show a different distribution of 100-A filaments in resting and locomotive cells: large aggregates in the former, small groups and single filaments in the latter. Colchicine in identical concentrations has a different effect on the motility of the two leukemias: locomotion in L5222 cells is slowed, while a slow locomotive activity is initiated in BNML cells. It can be argued that these changes in motility that lead to a convergence in the locomotive activity are connected with loss of microtubules and a similarly modified surface structure.

Adhesion patterns of cell interactions revealed by reflection contrast microscopy

Abstract Reflection contrast in combination with phase contrast microscopy was utilized for the study of adhesion patterns of locomotive L5222 rat leukemia cells. It was found that for cells moving in a spherical shape on the glass surface, adhesions were very faint. This inconspicuous pattern, however, became very distinct, as soon as the cells changed to a flattened configuration. Such a change took place when leukemia cells came into contact with other spread cells and started to move under these cells. Reflection contrast further showed that in the pathway of the locomoting L5222 cells the adhesions of the overlying spread cells were momentarily detached from the substrate. It is concluded that the combination of reflection contrast and phase contrast represents a good tool for gaining new information on the interaction of motility and formation of adhesions.

Motility of L5222 leukemia cells within the mesentery

SummaryMicrocinematography, together with histology at the semithin and ultrathin section levels, was utilized for the demonstration of the motile behavior of L5222 rat leukemia cells within a living tissue, the mesentery. On days 1–6 after intraperitoneal implantation of L5222 cells, a period corresponding to the life span of leukemic animals, the pieces of mesentery infiltrated in vivo by leukemia cells were transferred into Rose chambers and filmed in vitro. The movements of the leukemia cells within the mesentery were qualitatively identical to those performed on glass, on spot motility and locomotion, both being in the characteristic polarized configuration recorded in earlier studies. The type of locomotion within the mesentery, however, was impressively influenced by the fibrillar structure of the organ. While thin elastic fibers were crossed by the leukemia cells by means of shape adaptation, thick collagen bundles represented, in most cases, true obstacles. Frequent changes of direction, short tracks and overall low speed of movement resulted. The structure of the mesentery was changed in time, after implantation, by massive thickening of the collagen bundles. These changes together with increasing numbers of leukemia cells, macrophages, mast cells, granulocytes and lymphocytes reduced the motility of L5222 cells.The mesentery infiltrated by L5222 cells is a promising model for studying the interaction of moving cells with structured and unstructured elements of the mesenchyme.

Patterns of motility in human leukemias: A study by time-lapse cinematography☆

Abstract The motile behavior of 24 human leukemia cell populations was recorded by means of time-lapse cinematography. Three basic modes of motility were considered in the evaluation: surface motility, on spot motility and, the translocative form, locomotion. While surface motility was displayed by all cells in good condition, the number of cells engaged in on spot motility and in locomotion was different for each leukemia and comprised a range from zero to near complete. In addition to this numerical aspect, the existence of cell-dependent modes of locomotion became evident. Based on a characteristic configuration, blast cells, promyelocytes, myelocytes, and granulocytes together with small, non-stimulated lymphocytes had their distinct locomotive patterns. On the other hand, blast cells of different origin were indistinguishable in their manner of movement. Thus, each leukemia presented its individual pattern of motility that was determined not only by the presence of one or more cell classes with specific modes of locomotion, but also by their numbers involved in this activity. This individuality was found to occur irrespective of the hematological diagnosis and could not be predicted. Whether there is any interrelation between the differing patterns of motility and the clinical course of a given leukemia remains to be established.

Interrelation of motility, shape, and surface architecture in human carcinoma cells

Abstract By use of microcinematography and scanning electron microscopy (SEM) motility, shape and surface architecture of eight tissue culture lines from human epidermoid carcinomas of the head and neck were studied. Time lapse films showed that the carcinoma cells displayed the two modes of motility: stationary and translocative, both interchangeable. While participation in either of the two activities varied for the different cell lines, the changes in shape and surface characteristics, which always accompanied the transition from stationary to translocative motility and vice versa, were a constant feature in all lines. Altogether, the combination of cinematography and SEM revealed the interdependence of motility, cell shape and surface configuration, and reemphasized our view that these features indicate activities rather than cellular nature.

Motility of L 5222 rat leukemia cells in the flattened state

SummaryEmperipolesis is the term for the assumed penetration of living cells into other living cells. As reported earlier, L 5222 rat leukemia cells, migrating in vitro, change from a spherical to a spread configuration when they meet flat cells, and continue to move in this shape within the contours of the target cells. Whether or not this close cellular association corresponded to emperipolesis could not be determined with phase and interference contrast cinemicrography alone. In combination with transmission electron microscopy, it could be demonstrated that the compartment, in which the spread leukemia cells move, is not the cytoplasm of the target cells, but the narrow space created by the target cells and the underlying glass surface. Thus, emperipolesis could be ruled out for L 5222 leukemia cells. On this basis the reported observations on emperipolesis are reviewed, and a critical attitude regarding the occurrence of emperipolesis in general is advocated.