Panoply™ Human LIFR Over-expressing Stable Cell Line

In recent years, circular RNAs (circRNAs) have been revealed to play important roles in carcinogenesis. Metastasis is the leading cause of death in patients with lung adenocarcinoma (LUAC). However, the contribution of circRNAs to LUAC metastasis remains unclear. Based on circBase data and tissue samples from our biobank, researchers found that expression of circCRIM1 (hsa_circ_0002346), a circRNA derived from exons 2, 3, and 4 of the CRIM1 gene, was significantly lower in LUAC samples than in normal controls. Both in vivo and in vitro experiments demonstrated that circCRIM1 inhibited LUAC invasion and metastasis. Using in vitro circRNA precipitation, luciferase reporter assays, and biotin-conjugated microRNA capture, they investigated the Ago2-dependent interaction between circCRIM1 and microRNA (miR)-93/miR-182. Mechanistically, they found that circCRIM1 promoted the expression of leukemia inhibitory factor receptor (LIFR), a well-known tumor suppressor, by recruiting miR-93 and miR-182. Clinical and pathological analysis showed that downregulation of circCRIM1 in LUAC was significantly associated with lymph node metastasis and TNM stage, and was an independent risk factor for overall survival in LUAC patients. These studies suggest that circCRIM1 can inhibit the invasion and metastasis of lung adenocarcinoma cells, making it a potential therapeutic target.

To evaluate the biological effects of LIFR, researchers performed Matrigel, Transwell, and wound-healing assays in A549 and H1299 cells. Invasion and migration of LIFR-overexpressing cells were significantly inhibited (Figure 1D, E). Both miR-182 and miR-93 act as oncogenic miRNAs, regulating multiple biological processes in lung cancer. Previous studies have demonstrated that overexpression of miR-182 and miR-93 significantly promotes cell proliferation, migration, and invasion by directly targeting tumor suppressor genes. Furthermore, elevated expression of miR-182 and miR-93 is significantly associated with poor prognosis in lung adenocarcinoma (LUAC) and numerous other cancers. Subsequent rescue experiments demonstrated that transfection of miR-182 and miR-93 mimics into LUAC cells overexpressing circCRIM1 significantly attenuated circCRIM1-mediated inhibition of cell invasion and migration. LIFR downregulation significantly enhanced the inhibition of cell invasion and migration induced by circCRIM1 overexpression (Figure 1F). Therefore, the RTCA assay was performed to identify the migratory capacity of LUAC cells by comparing the results of si-circCRIM1, si-LIFR, and si-circCRIM1 + si-LIFR. The results showed that circCRIM1 inhibited invasion and migration through the miR-182/93-LIFR axis, and according to the rescue assay, the function of circCRIM1 was partially dependent on LIFR (Figure 1G).

Figure 1. LIFR is the direct target of miR-182 and miR-93 and suppresses leading cause of LUAC cell metastasis. (Wang L, et al., 2019)