Modulating mesenchymal stromal cell function with cholesterol synthesis inhibitors

There is increasing evidence that statins, inhibitors of 3-hydroxyl-3-methylglutaryl coenzyme A reductase, can effectively be used not only in the treatment of hypercholesterolemia, but also in other human disorders; indeed, statins have strong anti-inflammatory and immunomodulatory effects, so that they can influence the onset and outcome of inflammation and autoimmunity. On the other hand, it has been shown that statins can affect growth and survival of solid tumour and leukemic cells, thus they have been proposed in the treatment of neoplasias as multiple myeloma, in association with drugs, as thalidomide, known to act on the cancer microenvironment. In the current view, tumor microenvironment include many cell types that interact with tumor cells: among them, stromal and endothelial cells, macrophages and dendritic cells, the various types of lymphocytes such as NK cells, B and T cells. The interplay between all these cell populations, and the balance between these, determines whether there is a tumour cell growth promotion or inhibition. In haematological malignancies, such as multiple myeloma, chronic lymphocytic and myeloid leukemias and follicular lymphomas, the survival, drug-resistance and proliferation of leukemic cells have been shown to be largely dependent on a supportive microenvironment, so that some cellular components of it, mainly mesenchymal stromal cells, cancer associated fibroblasts and macrophages, are now proposed as targets of new therapies. Herein, we analyze the effects that statins can exert on cancer cells, stromal cells and human natural killer cells, to discuss whether they can be proposed as anti-cancer drugs.