Abstract
BackgroundEsophageal squamous cell carcinoma (ESCC) is highly malignant with highly invasive and metastatic capabilities and poor prognosis. It is believed that the ESCC cancer stem-like cells (ECSLCs) are critical for tumorigenicity, invasion and metastasis of ESCC. However, the properties of ECSLCs vary with different markers used in isolation, so that new and more effective markers of ECSLCs need to be identified. This study aimed to estimate the potentiality of Cripto-1 (CR-1) as an ECSLC surface marker and investigate the clinical significance of CR-1 expression in ESCC.MethodsESCC cells with CR-1 high or CR-1low were obtained by flow cytometry then their self-renewal capability and tumorigenicity were compared by colony and limiting dilution sphere formation analysis in vitro and xenograft in nude mice in vivo, respectively. Knockdown of CR-1 expression in ESCC cells was conducted with short hairpin RNA. Cell migration and invasion were examined by scratch test and matrigel transwell assay, respectively. Metastatic capability of ESCC cells was assayed by a mouse tail vein metastasis model. The levels of CR-1 expression in cancerous and paired adjacent normal tissues were assessed by IHC and qRT-RCR.ResultsCR-1high subpopulation of ESCC cells isolated by FACS expressed high level of genes related to stemness and epithelial-mesenchymal transition (EMT), and possessed high capacities of self-renewal, tumorigenesis, invasion and metastasis. Suppression of CR-1 expression significantly reduced the expression of stemness- and EMT-related genes and the capabilities of self-renewal in vitro, tumorigenicity and metastasis in vivo in ESCC cells. In the clinical ESCC specimens, the expression levels of CR-1 in cancerous tissues were positively correlated to TNM stage, invasive depth, and lymph node metastasis. Cox regression analysis indicated that CR-1 was an independent indicator of prognosis. The expression of CR-1 was found overlapping with aldehyde dehydrogenase 1A1 (ALDH1A1), an intracellular marker for ESCLCs, in ESCC cell lines and specimens.ConclusionsCR-1 is a functional and cell surface ECSLC marker, and an independent prognostic indicator as well as a potential therapeutic target for ESCC.
Highlights
Esophageal squamous cell carcinoma (ESCC) is highly malignant with highly invasive and metastatic capabilities and poor prognosis
CR-1high cells isolated from ESCC cells possess cancer stem-like cells (CSLCs) properties We first examined the expression of CR-1 in two human ESCC cell lines EC109 and TE-1, and found that both of the two cell lines expressed CR-1 at mRNA and protein levels, and the expression level of EC109 cells was approximately 2 ~ 3 fold higher than that of TE-1 cells (Additional file 1: Figure S1A and S1B)
epithelial-mesenchymal transition (EMT) has been believed to associate with early steps of invasion and metastasis of epithelial origin cancer cells and generation of CSLCs [21], we examined the differential expression of EMT characteristic molecules and EMT-related transcription factors in CR1high and CR-1low cells by qRT-PCR
Summary
Esophageal squamous cell carcinoma (ESCC) is highly malignant with highly invasive and metastatic capabilities and poor prognosis. It is believed that the ESCC cancer stem-like cells (ECSLCs) are critical for tumorigenicity, invasion and metastasis of ESCC. Results: CR-1high subpopulation of ESCC cells isolated by FACS expressed high level of genes related to stemness and epithelial-mesenchymal transition (EMT), and possessed high capacities of self-renewal, tumorigenesis, invasion and metastasis. Suppression of CR-1 expression significantly reduced the expression of stemness- and EMT-related genes and the capabilities of self-renewal in vitro, tumorigenicity and metastasis in vivo in ESCC cells. Our and other groups have isolated and characterized ESCC cancer stem-like cells (ECSLCs) using aldehyde dehydrogenase 1A1 (ALDH1A1) [4], CD44 [5], p75NTR [6, 7] and CD90 [8] as markers. The properties of ECSLCs vary with different markers used in isolation, so that new and more effective markers of ECSLCs need to be identified
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
