:: CAST: A Chemotherapy Active Support Technology

Molecular mechanism of resistance to drugs

A major reason for such drug resistance is the presence of proteins called P-gp within the membrane of the cancer cells. P-gp proteins are pumps that actively extrude the "activated" chemotherapeutic agents from the interior of the cancer cells to the extracellular space where they can no longer exert their anti-tumor action (Fig. 1). By preventing accumulation of drugs inside the cancer cells, P-gp pumps action seriously impairs the efficacy of treatments. Moreover, this pump is not very selective and will expel the vast majority of chemotherapeutic agents encountered, leaving very few therapeutic options whenever the cancer cells express much P-gp.

Figure 1: Extrusion of chemotherapeutic agents through P-gp pump

One of the negative effects of chemotherapy is the selection for survival of cancer cells overexpressing P-gp from an initially heterogeneous population for P-gp expression. The cells overexpressing P-gp pumps indeed manage to survive the initial chemotherapy to possibly form a new clonal population of cancer cells from now on refractory to most chemotherapeutic agents (Fig. 2). Chemotherapy resistance is established.

Figure 2: Chemotherapy-induced drug resistance Chemotherapy

What makes CAST a multivalent formula acting as a chemosensitizer and an inhibitor of metastasis as well ?