Effect of single wall carbon nanotubes on human HEK293 cells

The influence of single-walled carbon nanotubes (SWCNTs).on human HEK293 cells is investigated with the aim of exploring SWCNTs biocompatibility. Results showed that SWCNTs can inhibit HEK293 cell proliferation, decrease cell adhesive ability in a dose- and time-dependent manner. HEK293 cells exhibit active responses to SWCNTs such as secretion of some 20-30 kd proteins to wrap SWCNTs, aggregation of cells attached by SWCNTs and formation of nodular structures. Cell cycle analysis showed that 25 mug/m1 SWCNTs in medium induced G(1), arrest and cell apoptosis in HEK293 cells. Biochip analysis showed that SWCNTs can induce up-regulation expression of cell cycle-associated genes such as p16, bax, p57, hrk, cdc42 and cdc37, down-regulation expression of cell cycle genes such as cdk2, cdk4, cdk6 and cyclin D3, and down-regulation expression of signal transduction-associated genes such as mad2, jak1, ttk, pcdha9 and erk. Western blot analysis showed that SWCNTs can induce down-regulation expression of adhesion-associated proteins such as laminin, fibronectin, cadherin, FAK and collagen IV. These results suggest that down-regulation of G(1) -assoicated cdks and cyclins and upregulation of apoplosis-associated genes may contribute to SWCNTs induced G(1), phase arrest and cell apoptosis. In conclusion, SWCNTs can inhibit HEK293 cells growth by inducing cell apoptosis and decreasing cellular adhesion ability. (C) 2004 Elsevier Ireland Ltd. All tights reserved.