Diversin is overexpressed in breast cancer and accelerates cell proliferation and invasion

Abstract

Diversin was recently reported to play roles in Wnt and JNK pathways. However, the expression pattern and biological roles of diversin in human breast cancer have not been reported. In the present study, we found that diversin was overexpressed in breast cancer specimens by immunohistochemistry and western blot. Significant association was observed between diversin overexpression and TNM stage (p = 0.0036), nodal metastasis (p = 0.0033), negative estrogen receptor expression (p = 0.0012) and triple-negative status (p = 0.0017). Furthermore, colony formation assay and matrigel invasion assay showed that knockdown of diversin expression in MDA-MB-231 cell line with high endogenous expression decreased cell proliferation and cell invasion. Transfection of diversin plasmid in MCF-7 cell line increased cell proliferation and invasion. Further analysis showed that diversin depletion downregulated JNK phosphorylation while its overexpression upregulated JNK phosphorylation. In conclusion, our study demonstrated that diversin was overexpressed in human breast cancers. Diversin could contribute to breast cancer cell proliferation and invasion.

Figure 1. Expression pattern of diversin protein in breast cancer tissues.

A. Negative diversin staining in the majority of normal breast tissue. B. Negative diversin staining in a case of ductal carcinoma in situ. C. Negative cytoplasmic staining of diversin in invasive ductal carcinoma. D. Strong nuclear staining of diversin in invasive ductal carcinoma. (Magnification, 200X) (Scale bar, 200 µm). E. Western blot analysis of diversin expression in 16 pairs of breast cancer and corresponding normal tissues.

Figure 2. Diversin expression in breast cancer cell lines.

A. Western blot analysis of diversin expression in breast cancer cell lines Her-18, MDA-MB-231, MDA-MB-435, T46D, MCF-7 and normal breast cell line MCF-10A. B. Western blot and realtime PCR analysis showed that diversin siRNA treatment markedly decreases diversin mRNA and protein levels in MDA-MB-231 (p<0.05). Transfection of diversin plasmid significantly upregulated its expression in MCF-7 cell line (p<0.05).

Figure 3. Diversin depletion inhibited and its overexpression promoted cell proliferation and invasion and JNK phosphorylation.

A. Colony formation assay showed that diversin knockdown inhibited proliferation in MDA-MB-231 cell line and its overexpression promoted proliferation in MCF-7 cell line. B. Diversin depletion decreased the level of 231 cell invasion and its overexpression facilitated invasion in MCF-7 cells. C. Western blotting revealed that knockdown of diversin decreased the levels of p-JNK and diversin transfection increased p-JNK, without significant changes of total JNK, p-p38 and p38. Scale bar, 200 µm.