Licochalcone A inhibits cell proliferation, migration, and invasion through regulating the PI3K/AKT signaling pathway in oral squamous cell carcinoma

Abstract

Background: Oral squamous cell carcinoma (OSCC) is one of the most common cancers, with high metastasis and mortality. Licochalcone A (LCA) is a chalconoid from the root of Glycyrrhiza inflata, which has anti-tumor, anti-inflammatory, anti-angiogenesis effects in many cancers. However, the mechanism that underlies LCA regulating cell proliferation, migration, and invasion in OSCC remains poorly understood. Methods: LY294002 or insulin-like growth factor 1 (IGF-1) were used to block or stimulate the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT) pathway in OSCC cells. Cell proliferation was investigated by MTT assay and proliferating cell nuclear antigen (PCNA) protein level using Western blot. The expression of metastasis-related protein was detected via Western blot. Cell migration and invasion abilities were evaluated by trans-well assay. A murine xenograft model of OSCC was established to investigate the anti-tumor effect of LCA in vivo. Results: Treatment of LCA inhibited cell proliferation in SCC4 and CAL-27 cells. Moreover, PI3K/AKT signaling was blocked by LY294002, and activated by IGF-1. LCA could suppress proliferation, migration, and invasion of OSCC cells, which was similar to the treatment of LY294002. In addition, LCA decreased IGF-1-induced OSCC progression. In a murine xenograft model, LCA treatment protected against tumor growth and metastasis in vivo. Conclusions: LCA might inhibit cell proliferation, migration, and invasion through regulating the PI3K/AKT pathway in OSCC, developing a potential chemotherapeutic agent for OSCC.

Keywords: Licochalcone A; PCNA; PI3K/AKT; invasion; migration; oral squamous cell carcinoma.

Figure 1

LCA inhibited cell proliferation of OSCC cells. (A and B) The cell viability of SCC4 and CAL-27 were detected at 24 and 48 hours after exposure of 0, 25, 50, 100 μM LCA. (C and D) The expression of PCNA protein was examined in SCC4 and CAL-27 at 24 and 48 hours after different concentrations of LCA treatment. *P<0.05. Abbreviations: LCA, Licochalcone A; OSCC, Oral squamous cell carcinoma; PCNA, proliferating cell nuclear antigen.

Figure 2

LCA blocked PI3K/AKT pathway in OSCC cells. (A and B) The expression of PI3K/AKT-related proteins was detected in SCC4 and CAL-27 cells after exposure of 100 μM LCA for 24 hours or 50 μM LY294002 for 2 hours. *P<0.05. Abbreviations: Con, control; LCA, Licochalcone A; OSCC, Oral squamous cell carcinoma.

Figure 3

LCA suppressed cell proliferation, migration, and invasion in OSCC cells. Cells were treated with 100 μM LCA for 24 hours or 50 μM LY294002 for 2 hours. The effect of LY294002 on cell viability (A and B) and PCNA protein level (C and D) was investigated in SCC4 and CAL-27 cells. (E–H) The effect of LCA and LY294002 on cell migration and invasion was analyzed in SCC4 and CAL-27 cells. *P<0.05. Abbreviations: Con, control; LCA, Licochalcone A; OSCC, Oral squamous cell carcinoma; PCNA, proliferating cell nuclear antigen.

Figure 4

LCA inhibited IGF-1-induced cell viability, migration, and invasion by regulating the PI3K/AKT pathway. Cells were stimulated with 100 ng/mL of IGF-1 for 20 minutes and then treated with 100 μM LCA for 24 hours. (A and B) The effect of LCA on IGF-1-mediated PI3K/AKT pathway was investigated in SCC4 and CAL-27 cells. (C and D) The expression of PCNA protein was detected in SCC4 and CAL-27 cells after IGF-1 and LCA treatment. (E and F) The number of migration cells was analyzed in SCC4 and CAL-27 cells. (G and H) The ability of invasion was investigated in cells with IGF-1 and LCA exposure. *P<0.05. Abbreviations: LCA, Licochalcone A; PCNA, proliferating cell nuclear antigen.

Figure 5

LCA decreased tumor growth and metastasis in vivo. (A) Tumor volume was detected every week after LCA or control treatment. (B) Tumor weight was measured at the end point. (C–E) The expression levels of PCNA, MMP-2, and MMP-9 protein were examined in tumor tissues after LCA insult. *P<0.05. Abbreviations: Con, control; LCA, Licochalcone A; PCNA, proliferating cell nuclear antigen.