Cancer stem-like cells photothermolysed by gold nanorod-mediated near-infrared laser irradiation

Abstract

Several studies have recently identified CD133 as a marker of cancer stem-like cells (CSCs) for various tumours. Such findings make CD133 a potential molecular target for tumour-selective therapeutic approach. In this study, fluorescence-tagged CD133 monoclonal antibody (anti-CD133) was conjugated to gold nanorods (GNRs), which are one of the anisotropic nanomaterials that can absorb near-infrared (NIR) laser light and convert it to heat for the destruction of tumour-initiating cells. To examine the specific targeting feature of GNRs conjugated with anti-CD133, CD133+ and CD133– glioblastoma cells were separately cultivated in the presence of the functionalised GNRs. Our results showed that anti-CD133-conjugated GNRs were extensively endocytosed by CD133+ cells, whereas anti-CD133 bound GNRs were not internalised by CD133– cells. To examine the efficacy of photothermolysis, anti-CD133-conjugated GNRs were first incubated with a mixed population of CD133+ and CD133– cells for 6 h, and the treated cells were then irradiated with 808-nm NIR laser light for a total of 15 min under different intensities. When examined by cell live/death dye, CD133+ cells were selectively targeted and killed, whereas non-CD133 expressing cells remained viable. On the basis of our study, GNRs bound with anti-CD133 monoclonal antibody have the potential to be utilised as a therapeutic thermal-coupling nano-scalpel to effectively target and destroy CSCs under NIR laser light exposure.