Abstract
BackgroundSignaling pathways critical for embryonic development re-emerge in adult pancreas during tumorigenesis. Aspartate β-hydroxylase (ASPH) drives embryonic cell motility/invasion in pancreatic development/differentiation. We explored if dysregulated ASPH is critically involved in pancreatic cancer pathogenesis.MethodsTo demonstrate if/how ASPH mediates malignant phenotypes, proliferation, migration, 2-D/3-D invasion, pancreatosphere formation, immunofluorescence, Western blot, co-immunoprecipitation, invadopodia formation/maturation/function, qRT-PCR, immunohistochemistry (IHC), and self-developed in vitro metastasis assays were performed. Patient-derived xenograft (PDX) models of human pancreatic ductal adenocarcinoma (PDAC) were established to illustrate in vivo antitumor effects of the third-generation small molecule inhibitor specifically against ASPH’s β-hydroxylase activity. Prognostic values of ASPH network components were evaluated with Kaplan-Meier plots, log-rank tests, and Cox proportional hazards regression models.ResultsASPH renders pancreatic cancer cells more aggressive phenotypes characterized by epithelial–mesenchymal transition (EMT), 2-D/3-D invasion, invadopodia formation/function as demonstrated by extracellular matrix (ECM) degradation, stemness (cancer stem cell marker upregulation and pancreatosphere formation), transendothelial migration (mimicking intravasation/extravasation), and sphere formation (mimicking metastatic colonization/outgrowth at distant sites). Mechanistically, ASPH activates SRC cascade through direct physical interaction with ADAM12/ADAM15 independent of FAK. The ASPH-SRC axis enables invadopodia construction and initiates MMP-mediated ECM degradation/remodeling as executors for invasiveness. Pharmacologic inhibition of invadopodia attenuates in vitro metastasis. ASPH fosters primary tumor development and pulmonary metastasis in PDX models of PDAC, which is blocked by a leading compound specifically against ASPH enzymatic activity. ASPH is silenced in normal pancreas, progressively upregulated from pre-malignant lesions to invasive/advanced stages of PDAC. Expression profiling of ASPH-SRC network components independently/jointly predicts clinical outcome of PDAC patients. Compared to a negative-low level, a moderate-very high level of ASPH, ADAM12, activated SRC, and MMPs correlated with curtailed overall survival (OS) of pancreatic cancer patients (log-rank test, ps < 0.001). The more unfavorable molecules patients carry, the more deleterious prognosis is destinated. Patients with 0–2 (n = 4), 3–5 (n = 8), 6–8 (n = 24), and 9–12 (n = 73) unfavorable expression scores of the 5 molecules had median survival time of 55.4, 15.9, 9.7, and 5.0 months, respectively (p < 0.001).ConclusionTargeting the ASPH-SRC axis, which is essential for propagating multi-step PDAC metastasis, may specifically/substantially retard development/progression and thus improve prognosis of PDAC.
Highlights
Signaling pathways critical for embryonic development re-emerge in adult pancreas during tumorigenesis
Aspartate β-hydroxylase (ASPH) renders pancreatic cancer cells more aggressive phenotypes characterized by epithelial– mesenchymal transition (EMT), 2-D/3-D invasion, invadopodia formation/function as demonstrated by extracellular matrix (ECM) degradation, stemness, transendothelial migration, and sphere formation
Endogenous ASPH propagated migration/2D invasion (Additional file 1: Figure S1D-G), EMT (Additional file 1: Figure S1J-L), 3D invasion (Additional file 1: Figure S1M), ECM degradation/remodeling (Additional file 1: Figure S1N-O), and stemness (Additional file 2: Figure S2B-I), which were substantially mitigated by the small molecule inhibitor or ASPH knocked out (KO) in AsPC-1 and HPAFII
Summary
Signaling pathways critical for embryonic development re-emerge in adult pancreas during tumorigenesis. Aspartate β-hydroxylase (ASPH) drives embryonic cell motility/invasion in pancreatic development/ differentiation. We explored if dysregulated ASPH is critically involved in pancreatic cancer pathogenesis. Pancreatic cancer is an intractable malignancy, with 458, 918 new cases and 432,242 deaths globally in 2018 [1]. The silent nature, multiple-drug resistance, rapid recurrence, and lack of early detection approaches necessitate active exploration of molecular mechanisms responsible for pancreatic tumorigenesis, progression, and metastasis, so that optimal targets for comprehensive therapy can be identified. ASPH is a potential driving factor for cell motility and invasion in pancreatic development/ differentiation in the embryo [3] and promotes oncogenesis in the adult. How ASPH regulates downstream effectors as a determinate for aggressive/invasive phenotypes of pancreatic cancer cells remains mysterious
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