Background: Cancer cells change phenotypes and properties when evolving from primary tumor cells to metastatic cells. These changes might affect the response to local anesthetics (LA). The aim of this study was to investigate if lidocaine or ropivacaine have a dose- dependent effect on cell viability and proliferation of a primary and a secondary colon carcinoma cell line in vitro.
Methods: The colon cancer cell lines SW 480, derived from primary tumor and SW620 from metastatic tumor in the same patient, were exposed to increasing log-concentrations of lidocaine and ropivacaine. Cell viability was measured using CellTiter Blue, and cell proliferation by PKH67, after exposure for up to 72 h.
Results: Cell viability was not affected after 24 h of exposure. However, the metastatic cell line SW620 showed a significant increase in cell viability at low concentrati ons after 48 and 72 h. Exposure to the higher, but clinically relevant, concentrations of both LA resulted in decreased cell viability in both cell lines. These higher concentrations also showed an inhibitory effect on cell proliferation after 72 h, which was more pronounced for ropivacaine.
Conclusions: Low concentrations of lidocaine and ropivacaine, as achieved in plasma by epidural infusion of LA, do not have direct antiproliferative effects on these colon cancer cell lines in vitro. Higher concentrations of LA, as during continuous local infiltration into tissues over 72 h, inhibit proliferation of both cancer cell lines. The increase in cell viability seen in SW620 should be investigated and underlying mechanisms further elucidated in future studies.