Focal adhesion kinase/Src family kinase axis-mediated tyrosine phosphorylation of metabolic enzymes facilitates tumor metastasis

Abstract Lymph node metastasis is crucial for esophageal squamous cell carcinoma (ESCC) malignancy. However, the molecular drivers and related mechanisms of lymph node metastasis in ESCC cells are unclear. In the present study, we found that the tyrosine kinase complex-focal adhesion kinase (FAK)/Src family kinase (SFK) axis specifically contributes to metabolic reprogramming by inducing the phosphorylation of ATP-citrate synthase (ACLY) Tyr542, Tyr652, and fructose-bisphosphate aldolase A (ALDOA) Tyr174, Tyr302, or Tyr328 sites in both primary and metastatic ESCC cells. Mechanistically, activated ACLY and ALDOA and their metabolites drive a transcriptional program in primary tumors that induces cyclin-dependent kinase 7/9 (CDK7/9) complex-mediated expression of DNA replication- and cell proliferation-related molecules. This process functions as an enabler of tumor malignancy. In metastatic tumor cells, metabolic enzymes and their products facilitate the transcriptional activity of Yamanaka factors to induce the activation of downstream plasticity-related molecules, fueling ESCC cell survival within metastatic lymph nodes. FAK/SFK axis-controlled ACLY and ALDOA tyrosine phosphorylation and downstream transcription factors and effectors in primary and metastatic ESCC cells are strongly associated with poor patient outcomes. We discovered a lead compound, quercetagitrin, that inhibits the phosphorylation of ALDOA at Tyr174, 302, and 328. Moreover, it has been shown to have antitumor effects alone or in combination with FAK/SFK inhibitors both in vivo and in vitro. The inhibition of tyrosine kinase-regulated metabolic enzyme activities and related signaling networks may be a potential strategy for the treatment and diagnosis of metastatic ESCC.