Ephrin-B2 reverse signaling regulates progression and lymph node metastasis of oral squamous cell carcinoma

Abstract

Oral squamous cell carcinoma (OSCC) is a common malignant tumor of the head and neck and frequently metastasizes to cervical lymph nodes. Aggressive local invasion and metastasis of OSCC are significant factors for poor prognosis. In this study, we investigated whether ephrin-B2 expressed in OSCC contributed to tumor progression and lymph node metastasis. Clinical specimens from patients with OSCC had robust ephrin-B2-positive tumor cells and ephrin-B2 protein level was associated with clinical stage, lymph node metastasis, and poor survival outcomes. We also determined that ephrin-B2 protein level was increased in OSCC cell lines compared to normal human oral keratinocytes and that its levels were associated with the migratory and invasive potential of OSCC cell lines. Transfection of an EFNB2–specific small interfering RNA (siRNA) into SAS-L1 cells significantly reduced proliferation, attachment, migration, and invasion through phosphorylation of the epidermal growth factor receptor, FAK, ERK1/2, p38, AKT, and JNK1/2 pathways. Furthermore, knockdown of EFNB2 significantly suppressed adhesion and transmigration of SAS-L1 cells toward human lymphatic endothelial cells. In addition, the growth rate of tumor xenografts and cervical lymph node metastases of OSCC were suppressed by local injection of EFNB2 siRNA. These results suggest that ephrin-B2 overexpression and activation of the ephrin-B2 reverse signaling pathway in tumor microenvironment in OSCC facilitates progression and lymph node metastasis via enhancement of malignant potential and interaction with surrounding cells.

Activation of EphrinB2 Signaling Promotes Adaptive Venous Remodeling in Murine Arteriovenous Fistulae

“…The effects of EphrinB2 may be mediated via phosphorylation of several downstream signaling pathways, consistent with absence of phosphorylation of p38-a, ERK1/2, JNK1/2/3, GSK-3a/b, EGFR, MSK1/2, Akt, HSP27, c-Jun, and FAK in Eph-rinB2 knockdown cells. 52 Our data are consistent with this report and show that activation of EphrinB2 signaling with EphB4-Fc both in vitro and in vivo activates several signaling pathways important for AVF maturation, such as eNOS, Akt1, ERK1/2, and p38. As one of the substrates for Akt1, phosphorylated eNOS generates nitric oxide in EC that regulates endothelial function, including angiogenesis and vessel dilation; 53,54 eNOS can also be regulated via ERK1/2 and p38, consistent with a complex network of signaling cascades.…”

Epithelial‐to‐mesenchymal transition in oral squamous cell carcinoma: Challenges and opportunities

“…Moreover, Ephs overexpression is correlated with tumor size, clinical stage, lymph invasion, recurrence and distant metastasis in OSCC. Therefore, Ephs also identified as independent poor prognostic factors in this cancer type and may be used as a prognostic marker for OSCC 133,134 …”

The differential expression of EPHB4 and ephrin B2 in cutaneous squamous cell carcinoma according to the grade of tumor differentiation: a clinicopathological study

“…26,27 Ephrin B2 overexpression was reported to be associated with a clinically advanced stage, lymph node metastasis, poor survival outcomes, and a negative response to therapy in HNSCC. 28,29 In this study, we found the expression of ephrin B2 in poorly differentiated CSCC was significantly increased compared to well-differentiated CSCC. In addition, ephrin B2 expression was also increased in metastatic cases.…”

“…Its expression was also indicated as a key regulator of vascular endothelial growth factor‐induced angiogenesis and lymphangiogenesis, and its blockade has been shown to inhibit angiogenesis and tumor growth 26,27 . Ephrin B2 overexpression was reported to be associated with a clinically advanced stage, lymph node metastasis, poor survival outcomes, and a negative response to therapy in HNSCC 28,29 . In this study, we found the expression of ephrin B2 in poorly differentiated CSCC was significantly increased compared to well‐differentiated CSCC.…”