1785

DNM2

dynamin 2;DNM2;dynamin 2

dynamin II|dynamin-2

19p13.2

protein-coding

Dynamin 2 is known as a protein involved in cell migration and endocytosis. We aimed to investigate the association between dynamin 2 expressions and tumor progression in early cervical carcinoma (IB1-IIA). Dynamin 2 expression was evaluated at protein level in thirty seven paraffin-embedded, formalin-fixed tissues including four normal cervix tissues and compared with pathologic risk factors for recurrence after surgery in thirty three patients with squamous cell carcinoma of the cervix. The expression of dynamin 2 was not different according to clinical stage and lympho-vascular space invasion. However, there were inverse correlations between dynamin 2 expression and the depth of invasion in cervix (p = 0.003) and lymph node (LN) metastasis (p = 0.001). To evaluate the mechanism of dynamin 2 in tumor invasion and metastasis, we performed an in vitro experiment with dynamin 2 siRNA using several cervical carcinoma cell lines such as HeLa, MS751 and SiHa cells. We found the inhibition of dynamin 2 using specific siRNA enhanced the expression of matrix metalloproteinase-2. These results suggested that dynamin 2 might be involved in preventing tumor invasion and LN metastasis, possibly in relation with extracellular matrix degradation, and may be a prognostic marker for these risk factors in early squamous cell carcinoma of the cervix.

Hypoxia-driven changes in the tumor microenvironment facilitate cancer metastasis. In the present study, we investigated the regulatory cross talk between endocytic pathway, hypoxia, and tumor metastasis. Dynamin 2 (DNM2), a GTPase, is a critical mediator of endocytosis. Hypoxia decreased the levels of DNM2. DNM2 promoter has multiple hypoxia-inducible factor (HIF)-binding sites and genetic deletion of them relieved hypoxia-induced transcriptional suppression. Interestingly, DNM2 reciprocally regulated HIF. Inhibition of DNM2 GTPase activity and dominant-negative mutant of DNM2 showed a functional role for DNM2 in regulating HIF. Furthermore, the opposite strand of DNM2 gene encodes miR-199a, which is similarly reduced in cancer cells under hypoxia. miR-199a targets the 3'-UTR of HIF-1alpha and HIF-2alpha. Decreased miR-199a expression in hypoxia increased HIF levels. Exogenous expression of miR-199a decreased HIF, cell migration, and metastasis of ovarian cancer cells. miR-199a-mediated changes in HIF levels affected expression of the matrix-remodeling enzyme, lysyloxidase (LOX). LOX levels negatively correlated with progression-free survival in ovarian cancer patients. These results demonstrate a regulatory relationship between DNM2, miR-199a, and HIF, with implications in cancer metastasis.