Abstract
Cancer stem-like cells (CSCs) are a rare tumorigenic population with the ability to self-renew in numerous cancer types. Their existence is considered a pivotal contributor to tumor recurrence. B7-H1 is a ligand of inhibitory inducible co-stimulator (ICOS) that is broadly expressed on various human cancers. ICOS acts as a ligand of programmed death-1 (PD-1) on T cells, induces the immune escape of cancer cells and also acts as a receptor mediating anti-apoptotic effects on cancer cells. However, the expression and function of B7-H1 on CSCs is not yet clear. In the present study, gastric cancer samples were collected and the B7-H1 expression in gastric cancer CSCs was detected. Ki67, a proliferation marker, was found to be expressed at a higher rate in B7-H1+ CSCs compared with the B7-H1− counterparts. SGC-7901 cells, a gastric cancer cell line, were cultured in serum-free medium to form sphere cells that possessed stem cell characteristics and could express B7-H1 with the stimulation of interferon-γ. The proliferative ability of sphere cells was enhanced following B7-H1 activation with recombinant PD-1 in vivo and in vitro. This effect could be eliminated by neutralizing B7-H1. Overall, B7-H1 can act as a stimulating receptor for CSCs, and induce CSC proliferation. Blocking B7-H1 on CSCs may possess therapeutic potential for treating gastric cancer.
Highlights
Gastric cancer is the second leading cause of cancer‐associated death worldwide [1]
Gastric CSCs (GCSCs) were defined as Lgr5+/CD326+/CD45‐ cells and 1.08±0.42% GCSCs were detected in gastric cancer (Fig. 1A)
The Ki67 expression rate in Lgr5+/B7‐H1+ cells was 32.22±11.60%, which was significantly higher compared with Lgr5+/B7‐H1‐ cells (24.80±10.33%; Fig. 1D), suggesting that B7‐H1 may act as a receptor transmitting signals into GCSCs and may induce GCSC proliferation
Summary
Current treatments for gastric tumors, including surgery, chemotherapy and radiotherapy, Key words: B7-H1, cancer stem-like cell, gastric cancer, proliferation are hampered by the existence of anti‐therapy tumor cells [2]. These cells are considered to be cancer stem‐like cells (CSCs), which possess self‐renewal abilities and can differentiate into all cell types in gastric cancer [3]. Certain cancer cell lines can form spheres when cultured in serum‐free medium [7,8,9] In this condition, sphere cells reveal a high capacity of tumorigenicity and express high stemness‐associated genes [7,8]. Gastric CSCs (GCSCs) have already been found in gastric cancer cell lines and primary tumors [9,10,11]
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
