In a previous paper we studied the influences of the basal lamina and its components on the invasive but nonmetastatic variant BSp 73 AS of a rat pancreatic adenocarcinoma. In continuation of this publication we used the in vivo strongly metastasizing but hardly invasive variant BSp 73 ASML. On plastic or glass supports the low passaged ASML-cells grew separately, spread very scarcely and remained passive. Compared to these standard culture conditions, the behaviour of the tumour cells could be modified by biomaterials like collagen type I/III and type IV, fibronectin, laminin, matrigel, lens capsule and basal lamina. On these substrata (compared to plastic supports) the ASML-cells showed increased spreading, filopodial outgrowth and secretion of membrane vesicles. Only signs of motility as well as penetration of the biomatrices could be observed. Interestingly, highly passaged ASML-cells displayed an increased tendency to spread even on plastic. Under dynamic conditions these cells even failed to adhere. Obviously the biomatrices in vitro as well as long-term passaging are able to lead the ASML-cells partly to reactivate the behaviour that is characteristic of malignant tumour cells. Additionally, there is some evidence that the ASML-cells in vitro can strongly respond to chemotactic stimuli by exhibiting both flattening and translocative motility.

Animals↗

PubMedDate not supplied

Influences of various substrata on morphology, motility, and invasiveness of rat tumour cells. I. Studies on the nonmetastatic variant BSp 73 AS.

BSp 73 AS is a highly invasive but scarcely metastatic cell line from a rat pancreatic adenocarcinoma. In vitro the AS-cells flatten and move actively and were originally able to form monolayers. Our highly passaged AS-cells had lost this ability and formed only two-dimensional clusters and small aggregates on plastic or glass supports. The in vitro behaviour of the As-cells, however, could be dramatically modified by biomatrices like collagen type I/III (vitrogen), Iaminin, fibronectin, basement membrane matrigel, lens capsule and bovine corneal endothelial basal lamina. On these substrata the AS-cells in most cases showed both faster and stronger attachment as well as spreading. Furthermore, degradation, alteration and penetration of the materials could be observed as well as filopodial outgrowth, secretion of membrane vesicles, modification of the cell shape and the forming of monolayers. Shaking the culture dishes decreased the attachment of the AS-cells to laminin, fibronectin and matrigel. Generally, the nonmetastatic AS-cells exhibited a rather aggressive activity in vitro. It could also be demonstrated that not only the cells alter the substratum, but also the cell phenotype is influenced by the extracellular components with which they were confronted.

Adenocarcinoma↗

PubMedDate not supplied

Ultrastructural studies on the lung colonization by nonmetastatic rat tumor cells.

The events during the settlement of BSp73AS (AS) tumor cells in the syngeneic rat lung are described. Although AS cells show highly invasive behavior in vitro, subcutaneous primary tumors grow solidly without detectable metastatic spreading. However, AS cells when applied to the syngeneic rats via the tail vein give rise to lung colonies which grow rapidly at the site of the cells' primary arrest in the capillaries. The colonization comprises formation of microemboli, penetration of the endothelium including the basal lamina, and invasion of the lung tissue. Within two weeks, large colonies develop, thereby compressing, invading, and destroying their surroundings without detectable preference in direction. This establishment of AS tumors in the lung reflects the high invasive potential of AS cells and displays many of the morphological features observed during the formation of colonies of metastatic cell lines. Thus, we conclude that a nonmetastatic tumor cell line, such as AS, may possess almost the whole set of properties necessary for successful metastasis.

Animals↗

PubMedDate not supplied

Tumor-related reconstitutive vascularization. An ultrastructural study.

The nonmetastatic derivative of the pancreatic adenocarcinoma BSp73 of the BDX rat, BSp73 AS (AS), was used to generate solid lung colonies by the intravenous route. Vascularization could be seen within the tumor nodules and in the surrounding, highly disorganized lung tissue. We concentrate here on the formation of capillaries in the surroundings of pulmonary AS foci. The formation of capillary lumina can be described as follows: first, a lumen is formed between an endothelial cell (EC) and its basal lamina (BL) by partial detachment of the EC. The denuded BL is then re-coated by EC protrusions until the lumen is newly lined. A similar process is observed at the abluminal surface of ECs of vessels just beneath the surface of alveolar lumina. In this case, ECs detach from their BL and generate stilts, thus bulging adluminally. The naked BL is then recoated by EC protrusions. Finally, small closed lumina are formed by the ECs. These events occurring during vascularization are interpreted as morphogenetic reactions of normal cells to tumor-derived stimuli. Vascularization of this kind takes place within peritumoral, disturbed alveolar tissue and appears to be aimed at reconstituting a normal alveolar histology in order to overcome the destruction caused by the tumor. In this study we show the highly complex reactions between normal and neoplastic tissue.

Adenocarcinoma↗

PubMedDate not supplied

An in vitro model study of BSp73 rat tumour cell invasion into endothelial monolayer.

In order to study the process of invasion in more detail we developed an in vitro model of the vessel wall. Rat tumour cells derived from an adenocarcinoma of the pancreas, BSp73 AS--of high invasive but low metastatic capacity--and BSp73 ASML--not invasive but highly metastatic--were compared for their mode of invasion into confluent monolayers of endothelial cells. Corneal as well as vascular endothelial cells were plated alternatively onto the basal lamina-like bovine lens capsule that was mounted in a combi-ring dish or reconstituted extracellular matrix (Basement Membrane Matrigel) as substrata. The endothelial monolayers were confronted with AS- and ASML-tumour cells. The interaction of the various cell types was followed by scanning and transmission electron microscopy. The invasive cell type AS was able to force the endothelial cells to retract and subsequently undermined the endothelial cell layer. In the noninvasive cell population ASML most cells remained in the typical roundish morphology and did not interact with the endothelial cell layers. Only a very minor fraction of ASML populations was able to attach to and also invade into the endothelial cell monolayer. It could be shown that AS-cells individually and as small groups penetrated the endothelial cell layer. The results of transmission and scanning electron microscopy suggest that endothelial cell retraction and underlapping of adjacent endothelial cells by tumour cells play an important role in invasion and extravasation through blood vessels. Against all expectations, the nonmetastasizing tumour cell variant (AS-cells) exhibited a dramatic invasive behaviour whereas the highly metastatic ASML-variant mostly retained its spherical shape and showed invasive activity only in exceptional cases.

Adenocarcinoma↗