Subject tumor cell invasion

Basically, harvest of invasive cells after any invasion assay (see Chapter 4) can be used to select a cell population with increased invasive ability. Poste et al. (1980) have used the chorioallantoic membrane (CAM) assay, a canine blood vessel perfusion-invasion chamber, or retrograde injection of tumor cells in the mouse bladder, to select tumor cell variants with respect to their invasive ability. B16-BL6 melanoma cells, widely used as a prototype of highly invasive metastatic cells have been subjected to six rounds of selection with the bladder system. The application of these three systems for selection is described in detail in the original paper (Poste et al., 1980), and will not be treated further here. 

The aim of the study was to compare the effects of LITT and hepatic resection on the immune response to residual intrahepatic tumor tissue and the growth of untreated liver metastases. Adenocarcinoma cells were implanted into hoth lohes of 60 Wistar Alhino Glaxo (WAG) rats. The left lohe tumor was treated either by LITT or partial hepatectomy. The control right lobe tumor was subjected to further investigation at regular intervals after treatment. The expression of several immunity factors was significantly enhanced at the invasion front of untreated control tumors after LITT compared to hepatic resection, which can then lead to reduced tumor growth (ISBERT et al. 2004). 

Fig. 5.1 Phases of cancer progression. When normal cells or tissues are subjected to genotoxic, cytotoxic, or carcinogenic insult, they may undergo transformation in a nitric-oxide-dependent manner. This process is characterized by activation of signaling cascades that result in increased proliferation and inhibition of apoptosis, causing neoplastic evolution in the process, which is accompanied by various biophysical and biochemical changes. Once the tumor is established, the release of angiogenic mediators is stimulated, leading to increased blood vessel formation, accompanied with increased vascularization of the tumor. Finally, in the metastatic phase, the tumors develop migratory and invasive properties that facihtate dissemination of the tumor and metastasis to secondary sites...

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