Zhang Juan1, Chu Dake1, Kiyohito Tanaka2, He Shuixiang3. 1. Department of Gastroenterology, The First Affiliated Hospital of Xi'an Jiaotong University, No. 277 Yan Tower West Road, Xi'an, 710061, Shaanxi, China. 2. Department of Gastroenterology, Kyoto Second Red Cross Hospital, Kyoto, 602-8026, Japan. 3. Department of Gastroenterology, The First Affiliated Hospital of Xi'an Jiaotong University, No. 277 Yan Tower West Road, Xi'an, 710061, Shaanxi, China. heshuixiangxa@163.com.
Abstract
BACKGROUND: Anoikis is a form of apoptosis, which inhibits metastatic cascade and deprives cancer cells with invasive capacity. Epidermal growth factor-like domain-containing protein 7 (EGFL7) is overexpressed in colorectal cancer (CRC) and is a potential biomarker for malignancy. The present study aimed was to investigate the effect and underlying mechanism of EGFL7 on CRC cell function. METHODS: EGFL7 expression in mutable human CRC cell lines and normal intestinal epithelial cell line HIEC were measured by qRT-PCR. To investigate the biological functions of EGFL7, loss-of-function experiments were performed by transfecting EGFL7 siRNA into SW620 and LoVo cells. Western blot analysis, MTT, invasion and anoikis assay were used to explore the underlying mechanism of EGFL7. RESULTS: EGFL7 was upregulated in several CRC cell lines as compared with normal intestinal epithelial cell line HIEC. Transfection of EGFL7 siRNA significantly decreased cell proliferation and invasion capacity of SW620 and LoVo cells. Additionally, EGFL7 inhibition markedly elevated anoikis through modulating anoikis marker proteins as reflected by increasing of cleaved-caspase-3 and cleaved-PAPR expression. Moreover, downregulation of EGFL7 inhibited PI3K and P-AKT expression. Furthermore, re-expression of PI3K remarkably reversed the effects of EGFL7 on SW620 cells. CONCLUSION: Overall, our findings suggested that EGFL7 acts as an oncogene, regulated CRC invasion and anoikis through PI3K/AKT signaling, which provided a theoretical basis for EGFL7 as a potential therapeutic target of CRC treatment.
BACKGROUND: Anoikis is a form of apoptosis, which inhibits metastatic cascade and deprives cancer cells with invasive capacity. Epidermal growth factor-like domain-containing protein 7 (EGFL7) is overexpressed in colorectal cancer (CRC) and is a potential biomarker for malignancy. The present study aimed was to investigate the effect and underlying mechanism of EGFL7 on CRC cell function. METHODS:EGFL7 expression in mutable human CRC cell lines and normal intestinal epithelial cell line HIEC were measured by qRT-PCR. To investigate the biological functions of EGFL7, loss-of-function experiments were performed by transfecting EGFL7 siRNA into SW620 and LoVo cells. Western blot analysis, MTT, invasion and anoikis assay were used to explore the underlying mechanism of EGFL7. RESULTS:EGFL7 was upregulated in several CRC cell lines as compared with normal intestinal epithelial cell line HIEC. Transfection of EGFL7 siRNA significantly decreased cell proliferation and invasion capacity of SW620 and LoVo cells. Additionally, EGFL7 inhibition markedly elevated anoikis through modulating anoikis marker proteins as reflected by increasing of cleaved-caspase-3 and cleaved-PAPR expression. Moreover, downregulation of EGFL7 inhibited PI3K and P-AKT expression. Furthermore, re-expression of PI3K remarkably reversed the effects of EGFL7 on SW620 cells. CONCLUSION: Overall, our findings suggested that EGFL7 acts as an oncogene, regulated CRC invasion and anoikis through PI3K/AKT signaling, which provided a theoretical basis for EGFL7 as a potential therapeutic target of CRC treatment.