ABSTRACT
Combination therapy of cancer is a rather new method, which involves the simultaneous use of various anticancer drugs and therapeutic strategies, and is becoming increasingly important for improving the quality of long-term cancer treatment (Lammers et al. 2010; Eldar-Boock et al. 2013). Typically, the combination therapy can modulate different signaling pathways in cancer cells in order to maximize the therapeutic effect compared with mono-drug therapy. One of the popular fields in the combination therapy is targeted delivery of antitumor drugs in various containers based on polymers (Rapoport 2007), carbon nanotubes (Liu et al. 2008), gold (You et al. 2010), magnetic nanoparticles (Purushotham et al. 2009), silica nanoparticles (Zou et al. 2013), and composite nanoparticles (Yagüe et al. 2010), and their release under external influence generated by infrared radiation (Gannon et al. 2007), alternating magnetic field (Bañobre-López et al. 2013) or radiofrequency radiation (Gannon et al. 2008). The main problem of this approach is the problem of drug container toxicity. Although the results of in vivo experiments on the suppression of tumor growth in mice give very promising results, the toxicity of materials during a prolonged treatment is questionable. For example, the intravenous administration of carbon nanotubes at a concentration of 100 µg · mL−1 after 7 days leads to inflammation in tissues (Lam et al. 2004). Gold and silicon dioxide are inert materials, their nanoparticles do not obtain a pronounced toxicity (Lasagna-Reeves et al. 2010), but the circulation time of the latter is a big problem. In addition, the complexities of this approach include physical limitations of external exposure, such as small penetration depth (IR radiation), difficulties of focusing (magnetic field), and side effects (radiation emission).
