CLCA2 overexpression suppresses epithelial-to-mesenchymal transition in cervical cancer cells through inactivation of ERK/JNK/p38-MAPK signaling pathways

Abstract

Cervical cancer is an important malignant tumor threatening the physical and mental health of women in the world. As a new calcium activated chloride channel protein, calcium activated chloride channel (CLCA2) plays an important role in tumorigenesis and development. But its role and exact regulatory mechanism in cervical cancer are still unclear. In our study, we found CLCA2 was significantly decreased in cervical cancer cells, and overexpression of CLCA2 inhibited the proliferation, migration and invasion, and promotes apoptosis of cervical cancer cells, and CLCA2 inhibited EMT (Epithelial-mesenchymal transition) through an p38 / JNK / ERK pathway. The results in vivo were consistent with those in vitro. In conclusion, overexpression of CLCA2 inhibited the progression of cervical cancer in vivo and in vitro. This may provide a theoretical basis for CLCA2 as a new indicator of clinical diagnosis and prognosis of cervical cancer or as a potential target of drug therapy.

Keywords: CLCA2; Cervical cancer; Progression; p38.

Fig. 1

Decreased expression of CLCA2 in cervical cancer cells. A qRT-PCR results indicated that the expression of CLCA2 decreased in cervical cancer cells. B Westernblot results showed that the expression of CLCA2 decreased in cervical cancer cells. *P < 0.05, **P < 0.001, t-test

Fig. 2

Overexpression of CLCA2 inhibits the proliferation, migration and invasion, and promotes apoptosis of cervical cancer cells. A qRT-PCR results indicated that the expression of CLCA2 increased after CLCA2 lentiviral plasmid transfection. B Overexpression of CLCA2 inhibited the proliferation of cervical cancer cells. C Overexpression of CLCA2 promoted apoptosis of cervical cancer cells. D Overexpression of CLCA2 inhibited the migration of cervical cancer cells. E Overexpression of CLCA2 inhibited the invasion of cervical cancer cells. *P < 0.05, **P < 0.001, t-test. N blank control, NC negative control. Scale bar = 25um

Fig. 3

CLCA2 inhibits EMT and p38 / JNK / ERK pathway in cervical cancer cells. Overexpression of CLCA2 up-regulated the expression of E-cadherin and down-regulated the expression of N-cadherin, snail, and twist. A qRT-PCR; B Westernblot; C Immunofluorescence(400×). D Westernblot results showed CLCA2 inhibited the expression of p-p38, p-JNK, p-ERK, and the expression level of p38, JNK, and ERK remained unchanged. *P < 0.05, **P < 0.001, t-test. Scale bar = 25um

Fig. 4

CLCA2 inhibits ocervical cancer growth and EMT in vivo. A, B CLCA2 overexpression led to a obvious reduction in tumor volume. C HE staining showed that the tumor cells had nuclear pyknosis and apoptosis. D TUNEL staining showed TUNEL positive cells were observed in tumors from CLCA2 overexpression treatment than those from NC treatment. E Immunofluorescence analysis of E-cadherin, N-cadherin, snail, twist and p-p38. F Westernblot analysis of E-cadherin, N-cadherin, snail, twist and p38. Scale bar = 100 μm, *P < 0.05, **P < 0.001, t-test. Scale bar = 25um

Fig. 5

Schematic representation of the mechanism with antitumor effect of CLCA2