Introduction: Human potassium chloride cotransporter-1 (KCC1) gene is expressed in endometrial cancer and related to metastasis of endometrial cancer. However, whether KCC1 contributes to invasion and metastasis of endometrial cancer has not been thoroughly investigated. The purpose of this study is to research the alternation effect of insulin-like growth factor I (IGF-I) on the expression of KCC1 in endometrial cancer HEC-1B cells and to explore the mechanism of how KCC1 regulates the invasion ability of HEC-1B cells through the extracellular signal-regulated kinase (ERK) signaling pathway.

Methods: First, the inhibitive effect of RNA interference to KCC1 was detected by semiquantitative reverse transcriptase-polymerase chain reaction. Western blot was used to measure expression changes of KCC1 after exposure to IGF-I in the HEC-1B cells. The change in quantity of phosphorylated ERK1/2 (p-ERK1/2) and cell invasion ability also were measured. After RNA interference and treatment with U0126, the quantity of p-ERK1/2 and the cell invasion ability were measured again.

Results: After the application of IGF-I on the HEC-1B cells, the expression of KCC1 and p-ERK1/2 increased dramatically, and the cell invasion ability advanced. RNA interference could inhibit the expression of KCC1, and the quantity of p-ERK1/2 and the cell invasion ability decreased even under the effect of IGF-I. Furthermore, after treatment with U0126, the cell invasion ability no longer advanced even under the effect of IGF-I either.

Conclusions: Insulin-like growth factors I can induce the upregulation of KCC1 gene, and KCC1 gene participates in the invasion ability of HEC-1B cells through the ERK signaling pathway.