Chromatin modified protein 4C (CHMP4C) facilitates the malignant development of cervical cancer cells

Abstract

Despite improvements in prevention and treatment, cervical cancer (CC) still poses a serious threat to women's health. CHMP4C (chromatin modified protein 4C) is a subunit of the endosomal sorting complex required for transport, which is expressed in both nucleus and cytoplasm. Here, we examined the effect of CHMP4C on the biological behavior of CC cells and the underlying mechanisms. We report that CHMP4C expression is higher in CC tissues, and high CHMP4C expression is associated with lower survival. Up-regulation of CHMP4C in C-33A cells accelerates cell proliferation, migration and invasion, whereas down-regulation of CHMP4C in Ca Ski cells had the opposite effect. Moreover, overexpression of CHMP4C induced activation of the epithelial-mesenchymal transition pathway, whereas depletion of CHMP4C inhibited activation. Our results suggest that CHMP4C contributes to the viability and motility of CC cells by modulating epithelial-mesenchymal transition and may facilitate the identification of novel biomarkers for CC therapy.

Keywords: EMT; cervical cancer; chromatin modified protein 4C; proliferation.

Fig. 1

CHMP4C was highly expressed in CC tissues and cell lines, which caused poor outcomes. (A) The expression of CHMP4C in CC tissues was significantly higher than that in healthy control tissues (P < 0.001). (B) The mRNA expression level of CHMP4C was up‐regulated in CC cell lines (HeLa, C‐33A and Ca Ski) compared with that in normal control cells Ect1/E6E7. (C) The higher the expression of CHMP4C, the lower the survival rate of patients with CC (P < 0.001). (D–F) The CHMP4C expression was obviously declined in C‐33A cells after transfection with si‐CHMP4C#1 and si‐CHMP4C#2 compared with that in the si‐con group. (G–I) The expression of CHMP4C was markedly elevated in Ca Ski cells after transfection with pcDNA3.1‐CHMP4C compared with that in the vector group. All experiments were repeated three times, and the error bars represent SD. **P < 0.01.

Fig. 2

Knockdown of CHMP4C in C‐33A cells inhibited proliferation, and up‐regulation of CHMP4C in Ca Ski cells accelerated proliferation. (A) CCK‐8 assay revealed that deletion of CHMP4C can decrease the cell viability in C‐33A cells. (B) The cell viability was markedly enhanced in Ca Ski cells after overexpression of CHMP4C. (C, D) Colony formation assay revealed that down‐regulation of CHMP4C can reduce the ability of cells to form colonies. (E, F) Up‐regulation of CHMP4C can increase significantly the number of colonies formed compared with that in the vector group. All experiments were repeated three times, and the error bars represent SD. **P < 0.01. A, absorbance.

Fig. 3

Deletion of CHMP4C suppressed invasion and migration of C‐33A cells, and overexpression of CHMP4C promoted invasion and migration of Ca Ski cells. (A, B) Through the Transwell assay, we found that knockdown of CHMP4C showed a significant inhibition on invasion and migration in C‐33A cells. (C, D) The number of invading and migrating cells was significantly increased after Ca Ski cells transfected with pcDNA3.1‐CHMP4C compared with that in the vector group. Scale bars: 200 μm (A, C). All experiments were repeated three times, and the error bars represent SD. **P < 0.01.

Fig. 4

CHMP4C mediates the occurrence of EMT in CC cells. (A, B) Down‐regulation of CHMP4C suppresses the EMT pathway in C‐33A cells. (C, D) Up‐regulation of CHMP4C promotes the EMT pathway in Ca Ski cells. All experiments were repeated three times, and the error bars represent SD. **P < 0.01.