Hsp70-2 is Highly Expressed in Nasopharyngeal Carcinoma and Involved in Nasopharyngeal Carcinoma Invasiveness

Nasopharyngeal carcinoma (NPC) has a highly metastatic character, and its metastasis is closely related to carcinogens. N, N’-Dinitrosopiperazine (DNP) is a specific carcinogen for NPC. Our previous studies have shown that DNP enhances NPC invasion through up-regulating the heat shock protein 70-2 (HSP70-2), but the mechanisms underlying its regulation in NPC metastasis are unclear. In this study, we found that HSP70- 2 expression in NPC tissue samples was significantly higher than that in the normal nasopharyngeal tissues. Moreover, HSP70-2 in metastatic cancer tissues was higher than that in primary cancer tissues. Importantly, NPC cell line, 5-8F cells with high metastatic potential had a significantly higher HSP70-2 expression and HSP70-2 ATPase activity than that in 6-10B cells with low metastatic potential. Strikingly, we further found that the NPC specific carcinogen, DNP induced HSP70-2 expression and increased HSP70-2 ATPase activity, displaying a dose dependence and time dependence. And DNP also enhances the interaction between HSP70-2 and ATPase. These results suggest that HSP70-2 participates in NPC invasiveness, and DNP-inducing HSP70-2 ATPase activity may be a novel mechanism of NPC metastasis.