Invasion in vitro

Abstract

To understand the mechanisms of tumour invasion a number of in vitro assays have been developed, in which test cells (invasive or non-invasive) have been confronted with normal cells or tissues (the host) and cultured in various ways. We will discuss here the methods by which invasion can be judged in such assays. Histology is the method that is used successfully by pathologists for the evaluation of tumour invasiveness in vivo. The major difficulty is that the relationship between the non-invasive counterpart and the host tissue is not known in vitro or in vivo. Some authors have attempted to quantify invasion on histologic sections, but a generally accepted method is not yet available. The potential contribution of time lapse cinematography to the study of the kinetic aspects of invasion is obvious. Optical systems which overcome the relative lack of transparency of three-dimensional tissues, however, do not exist. Electron microscopy has contributed by providing details about the interactions between invasive cells on the one hand and normal cells as well as intercellular matrices on the other hand. Subpopulations of highly invasive and metastatic cells were collected after repeated migration through normal tissues in two-compartment assays. Attempts to evaluate the cytotoxic effect of invasive cells confronting radiolabelled cells or tissues have produced equivocal results. In contrast, measurements of radioactivity in the medium of labelled substrata have demonstrated the lytic effect of invasive cells on the extracellular matrix. It is concluded that further search for better methods to analyze and quantitate invasion is needed. So far, corroborative analysis by various methods seems to be the best policy.

Ras (proto)oncogene induces N-linked carbohydrate modification: temporal relationship with induction of invasive potential.

“…Mouse class I MHC antigens were isolated by immunoprecipitation with specific anti-H-2 antibody (Figure 8) Morphologically transformed T15 cells cultured and analysed in the continuous presence of DEX, were aggressively invasive in an organotypic invasion assay. In this assay (Mareel, 1983), cell aggregates are confronted with a fragment of normal chick heart tissue. Invasive cells penetrate and destroy the chick heart, but nonmalignant cells do not.…”

The role of cancer cell motility in invasion

“…A comprehensive survey of in vitro models of invasion was given by Mareel (61). In general, the reliability of the information yielded by in vitro models improves with their increasing complexity or 'naturalness', which corresponds largely to the progress from two-dimensional to three-dimensional arrangements (62,63).…”

U-77,863: a novel cinnanamide isolated from Streptomyces griseoluteus that inhibits cancer invasion and metastasis

“…Invasion is required for tumor cells to leave the primary tumor (local invasion), enter the vasculature (intravasation) and for circulating tumor cells to leave the vasculature (extra- vasation). We [34-36, [41][42][43][44] and others [45][46][47][48][49][50] have shown that invasion in vitro and metastasis formation in vivo correlate in a variety of human and rodent cell lines. Thus, development of drugs which inhibit invasion should prevent metastasis.…”