Manganese oxide nanoparticles inhibit selectively the in vitro and in vivo growth of human colorectal SW620 adenocarcinoma cells

A promising area of oncotherapy is the use of nanomaterials for diagnostics and imaging, as well as for delivering drugs and direct effect agents to tumour cells. We used earlier manganese oxide nanoparticles (NP MnO) as magnetic resonance imaging agents for visualisation and suppression of in vitro and in vivo growth of human glioblastoma cells. The present study was to demonstrate the selective antitumor effect of NP MnO against human tumour cells of different tissue origins, in particular, cells SW620, human colorectal adenocarcinoma. It was shown that NP MnO can inhibit selectively in vitro growth of SW620 cells; the index of selective cytotoxicity against human colorectal adenocarcinoma cells was 20. The range of optimal NP MnO doses was determined using subcutaneous introduction of the nanoparticles to SCID mice; the doses no more than 0.96 mgMn kg(-1) had practically no local toxic effect in the animals. The subcutaneous administration of NP MnO in the specified dose range inhibited the growth of SW620 xenografts in SCID mice and led to an increase in their life expectancy. With administered NP MnO in doses of 0.32 and 0.96 mgMn kg(-1), the index of inhibition of tumour growth for 21 days from the beginning of the introduction of nanoparticles was 43.0% and 69.8%, respectively. NP MnO seem promising for developing nanotheranostics agents for the visualisation and treatment of human tumours of different tissue origins.