Abstract:
Membrane fluidity has long been an underexplored area associated with the motility and invasiveness of metastatic cancer cells. However, despite its widespread use, the term remains loosely defined and often encompasses multiple distinct biophysical properties of the plasma membrane. As a result, it remains unclear which specific membrane changes accompany the transition of cancer cells to an invasive state. In this study, we examine how different biophysical parameters of the plasma membrane change during cancer cell invasion. Recognising that cellular behaviour can be strongly influenced by experimental context, we also consider how dimensionality and model system affect the interpretation of membrane properties. Using fluorescence lifetime imaging microscopy (FLIM) of distinct probes, we assess lipid packing from a range of perspectives by measuring membrane hydration, cholesterol content and tension, as well as using fluorescence recovery after photobleaching (FRAP) to investigate membrane mobility in invasive cancer cells. Together, these measurements allow us to interrogate the distinct membrane properties that are often collectively described as "fluidity" in order to understand how these properties change during the acquisition of invasive behaviour.
