Mechanistic approach to evaluate the effectiveness of anticancer drugs
Apart from the genetic and molecular changes, there is an evidence showing that cancer cells during invasion and metastasis undergo changes in their structure and behaviour manifested in altered mechanical phenotype. The development of techniques that enable to measure mechanical properties of living, individual cells such as atomic force microscopy (AFM) or optical stretcher confirms this statement. Currently, one can clearly state that individual cancer cells are more deformable than the normal ones. This applies to the majority of tumour types including bladder, breast, prostate, ovarian, colon, thyroid, kidney, and other cancers. Very rarely, stiffening of cancerous cells has been observed as, for example, for cervical cancer, hepatocellular carcinoma or leukemia.As soon as AFM was implemented into studies of biological samples like cells, first AFM-based measurements of the drug influence were carried out on living cells. Technological advancements of atomic force microscopy delivered data showing that elasticity of single cells in mainly maintained by actin filaments. However, AFM-based elasticity measurements have been applied to establish the effect of microtubule influencing drugs.Cytoskeleton affecting drugs are not the only compounds studied by means of atomic force microscopy. Recently, many studies have appeared showing that AFM can be an excellent tool to investigate morphology, as well as mechanical properties of drug treated cells. Such studies indicate great potential of AFM in the search for new parameters describing the effectiveness of anti-cancer drugs at the single cell level.