👤 Emmanuel B Asiedu

Drug chemoresistance remains a major reason of treatment failure in cancer patients. In head and neck squamous cell carcinoma (HNSCC), the seventh most common cancer worldwide, cisplatin chemotherapy remains the gold standard for advanced tumors but often faces loss of responsiveness and the drawback of relapse. We previously showed that the metabolic and angiogenic factor angiopoietin-like 4 (ANGPTL4) is a molecular biomarker of oral dysplasia and HNSCC. We also found that through interaction with Neuropilin 1 (NRP1), ANGPTL4 activates proliferative and migratory pathways that contribute to HNSCC development. Using HNSCC xenografts, patient tumor-derived organoids, tumor spheroids, and HNSCC cell lines, CAL27, HN13, and HN4, here we provide evidence of the role of ANGPTL4 in the development of platinum-based chemoresistance in HNSCC through the promotion of DNA damage response (DDR) and homologous recombination (HR). ANGPTL4 enhanced these mechanisms by promoting phosphorylation of RAD51 recombinase in Tyr Show less

The molecular mechanisms whereby angiopoietin-like 4 (ANGPTL4), a pluripotent protein implicated in cancer development, contributes to head and neck squamous cell carcinoma (HNSCC) growth and dissemination are unclear. We investigated ANGPTL4 expression in human normal oral keratinocytes (NOKs), dysplastic oral keratinocytes (DOKs), oral leukoplakia cells (LEUK1), and HNSCC cell lines, as well as in tissue biopsies from patients with oral dysplasia, and primary and metastatic HNSCC. We further examined the contribution of ANGPTL4 cancer progression in an HNSCC orthotopic floor-of mouth tumor model and the signaling pathways linking ANGPTL4 to cancer cell migration. ANGPTL4 expression was upregulated in premalignant DOKs and HNSCC cell lines compared to NOKs and was increased in tissue biopsies from patients with oral dysplasia, as well as in primary and metastatic HNSCC. We also observed that downregulation of ANGPTL4 expression inhibited primary and metastatic cancer growth in an HNSCC orthotopic tumor model. Interestingly, ANGPTL4 binding to the neuropilin1 (NRP1) receptor led to phosphorylation of the focal adhesion protein, paxillin (PXN), and tumor cell migration; this was dependent on the tyrosine kinase ABL1. Treatment with the ABL1 inhibitor, dasatinib and small interfering RNA silencing of NRP1 or ABL1 expression blocked PXN phosphorylation and tumor cell migration. Our findings suggest an early, sustained, and angiogenesis-independent autocrine role for ANGPTL4 in HNSCC progression and expose ANGPTL4/NRP1/ABL1/PXN as an early molecular marker and vulnerable target for the prevention of HNSCC growth and metastasis. Show less