Gli1-mediated tumor cell-derived bFGF promotes tumor angiogenesis and pericyte coverage in non-small cell lung cancer.

BACKGROUND: Tumor angiogenesis inhibitors have been applied for non-small cell lung cancer (NSCLC) therapy. However, the drug resistance hinders their further development. Intercellular crosstalk between lung cancer cells and vascular cells was crucial for anti-angiogenenic resistance (AAD). However, the understanding of this crosstalk is still rudimentary. Our previous study showed that Glioma-associated oncogene 1 (Gli1) is a driver of NSCLC metastasis, but its role in lung cancer cell-vascular cell crosstalk remains unclear. METHODS: Conditioned medium (CM) from Gli1-overexpressing or Gli1-knockdown NSCLC cells was used to educate endothelia cells and pericytes, and the effects of these media on angiogenesis and the maturation of new blood vessels were evaluated via wound healing assays, Transwell migration and invasion assays, tube formation assays and 3D coculture assays. The xenograft model was conducted to establish the effect of Gli1 on tumor angiogenesis and growth. Angiogenic antibody microarray analysis, ELISA, luciferase reporte, chromatin immunoprecipitation (ChIP), bFGF protein stability and ubiquitination assay were performed to explore how Gli1 regulate bFGF expression. RESULTS: Gli1 overexpression in NSCLC cells enhanced the endothelial cell and pericyte motility required for angiogenesis required for angiogenesis. However, Gli1 knockout in NSCLC cells had opposite effect on this process. bFGF was critical for the enhancement effect on tumor angiogenesis. bFGF treatment reversed the Gli1 knockdown-mediated inhibition of angiogenesis. Mechanistically, Gli1 increased the bFGF protein level by promoting bFGF transcriptional activity and protein stability. Importantly, suppressing Gli1 with GANT-61 obviously inhibited angiogenesis. CONCLUSION: The Gli1-bFGF axis is crucial for the crosstalk between lung cancer cells and vascular cells. Targeting Gli1 is a potential therapeutic approach for NSCLC angiogenesis.

Gli1 promotes epithelial-mesenchymal transition and metastasis of non-small cell lung carcinoma by regulating snail transcriptional activity and stability.

Metastasis is crucial for the mortality of non-small cell lung carcinoma (NSCLC) patients. The epithelial-mesenchymal transition (EMT) plays a critical role in regulating tumor metastasis. Glioma-associated oncogene 1 (Gli1) is aberrantly active in a series of tumor tissues. However, the molecular regulatory relationships between Gli1 and NSCLC metastasis have not yet been identified. Herein, we reported Gli1 promoted NSCLC metastasis. High Gli1 expression was associated with poor survival of NSCLC patients. Ectopic expression of Gli1 in low metastatic A549 and NCI-H460 cells enhanced their migration, invasion abilities and facilitated EMT process, whereas knock-down of Gli1 in high metastatic NCI-H1299 and NCI-H1703 cells showed an opposite effect. Notably, Gli1 overexpression accelerated the lung and liver metastasis of NSCLC in the intravenously injected metastasis model. Further research showed that Gli1 positively regulated Snail expression by binding to its promoter and enhancing its protein stability, thereby facilitating the migration, invasion and EMT of NSCLC. In addition, administration of GANT-61, a Gli1 inhibitor, obviously suppressed the metastasis of NSCLC. Collectively, our study reveals that Gli1 is a critical regulator for NSCLC metastasis and suggests that targeting Gli1 is a prospective therapy strategy for metastatic NSCLC.

Triptolide suppresses the growth and metastasis of non-small cell lung cancer by inhibiting ß-catenin-mediated epithelial-mesenchymal transition.

Non-small cell lung cancer (NSCLC) is characterized by a high incidence of metastasis and poor survival. As epithelial-mesenchymal transition (EMT) is well recognized as a major factor initiating tumor metastasis, developing EMT inhibitor could be a feasible treatment for metastatic NSCLC. Recent studies show that triptolide isolated from Tripterygium wilfordii Hook F attenuated the migration and invasion of breast cancer, colon carcinoma, and ovarian cancer cells, and EMT played important roles in this process. In the present study we investigated the effect of triptolide on the migration and invasion of NSCLC cell lines. We showed that triptolide (0.5, 1.0, 2.0 nM) concentration-dependently inhibited the migration and invasion of NCI-H1299 cells. Triptolide treatment concentration-dependently suppressed EMT in NCI-H1299 cells, evidenced by significantly elevated E-cadherin expression and reduced expression of ZEB1, vimentin, and slug. Furthermore, triptolide treatment suppressed ß-catenin expression in NCI-H1299 and NCI-H460 cells, overexpression of ß-catenin antagonized triptolide-caused inhibition on EMT, whereas knockout of ß-catenin enhanced the inhibitory effect of triptolide on EMT. Administration of triptolide (0.75, 1.5 mg/kg per day, ip, every 2 days) for 18 days in NCI-H1299 xenograft mice dose-dependently suppressed the tumor growth, restrained EMT, and decreased lung metastasis, as evidence by significantly decreased expression of mesenchymal markers, increased expression of epithelial markers as well as reduced number of pulmonary lung metastatic foci. These results demonstrate that triptolide suppresses NSCLC metastasis by targeting EMT via reducing ß-catenin expression. Our study implies that triptolide may be developed as a potential agent for the therapy of NSCLC metastasis.