Panoply™ Human LGR5 Over-expressing Stable Cell Line

Leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) has recently been identified as a reliable marker for colorectal cancer stem cells (CSCs). Previous studies have shown that LGR5 plays a pro-tumorigenic role in cervical cancer by activating the Wnt/β-catenin pathway. Here, researchers demonstrate that elevated LGR5 expression in cervical cancer cells enhances tumor sphere formation efficiency, confers chemoresistance to cisplatin, enhances cell migration, invasion, and clonogenicity, and increases the expression of stem cell-associated transcription factors in vitro. Unlike LGR5- cells, modulated LGR5+ cells are highly tumorigenic in vivo. Furthermore, modulated LGR5+ cells can differentiate into both LGR5+ and LGR5- cells both in vitro and in vivo, establishing a cellular hierarchy. Finally, researchers discovered that the LGR5-induced enhancement of tumor sphere formation efficiency can be modulated by either inhibiting or activating the Wnt/β-catenin pathway in cervical cancer cells. Together, these results suggest that LGR5 plays an important oncogenic role by promoting cervical CSC characteristics and may represent a potential clinical target.

To investigate the effect of LGR5 on the self-renewal capacity of cervical cancer cells (CSCs), one of the most important characteristics of cervical cancer stem cells (CSCs), researchers cultured LGR5-overexpressing cells (SiHa-LGR5 and HeLa-LGR5), LGR5-knockdown cells (SiHa-shLGR5 and HeLa-shLGR5), and control cells in serum-free medium under conditions optimal for tumor sphere growth. LGR5-overexpressing cells and control cells formed typical tumor spheres, while LGR5-knockdown cells failed to form any tumor spheres and only formed a few cell aggregates (Figure 1a). To compare tumor sphere-forming ability, 200 cells were seeded per well in 24-well plates and cultured in conditioned medium for three passages. The researchers found that in both SiHa and HeLa cell lines, LGR5-overexpressing cells formed 2.0-4.5-fold more tumor spheres than control cells (Figure 1b). LGR5 deficiency reduced sphere formation efficiency by 25% to 60% in SiHa cells, while HeLa-shLGR5 cells rarely or completely formed spheres (Figure 1c). Sphere formation efficiencies were 8.7% and 3.6% for SiHa-LGR5 and HeLa-LGR5 cells, respectively, compared to 2.0% and 1.3% for SiHa-AcGFP and HeLa-AcGFP cells. Furthermore, sphere formation efficiencies were 0.7% and 0.3% for SiHa-shLGR5 and HeLa-shLGR5 cells, respectively, compared to 1.3% and 1.0% for SiHa-shControl and HeLa-shControl cells, respectively (Figure 1d). These data suggest that elevated LGR5 expression enhances the self-renewal capacity of cervical cancer cells.

Figure 1. LGR5-overexpressing cervical cancer cells exhibit enhanced self-renewal capacity. (Cao H Z, et al., 2017)