Abstract:

Objective To investigate dinitrosopiperazine（DNP）-induced expression of HSP70-2 in the nasopharyngeal carcinoma （NPC） cell line 6-10B，and examine whether it contributes to metastasis. Methods The MTT assay was used to screen for non-toxic concentrations of DNP，then the DNP was added to 6-10B cells to induce HSP70-2 expression. Protein levels were measured using indirect immunofluorescence and Western blotting. A dose-response curve for DNP-induced HSP70-2 expression was generated. HSP70-2 mRNA levels were quantitated using RT-PCR. The metastatic potential of 6-10B cells as a function of HSP70-2 expression level was determined. Results DNP at concentrations up to 100 μmol/L appeared to be non-toxic to 6-10B cells. Exposing these cells to DNP up-regulated HSP70-2 expression in a dose-dependent manner， with the protein localizing primarily to the cytoplasm. However， HSP70-2 mRNA levels were similar in treated and untreated cells. Conclusions DNP up-regulates HSP70-2 expression in 6-10B cells by post-transcriptional regulation，and this up-regulation may contribute to NPC metastasis.

Key words: Nasopharyngeal neoplasm, Nitroso-compound, Dinitrosopiperazine, Heat shock protein 70-2