Small-Molecule Inhibition of GCNT3 Disrupts Mucin Biosynthesis and Malignant Cellular Behaviors in Pancreatic Cancer

Abstract

Pancreatic cancer is an aggressive neoplasm with almost uniform lethality and a 5-year survival rate of 7%. Several overexpressed mucins that impede drug delivery to pancreatic tumors have been therapeutically targeted, but enzymes involved in mucin biosynthesis have yet to be preclinically evaluated as potential targets. We used survival data from human patients with pancreatic cancer, next-generation sequencing of genetically engineered Kras-driven mouse pancreatic tumors and human pancreatic cancer cells to identify the novel core mucin-synthesizing enzyme GCNT3 (core 2 b-1,6 N-acetylglucosaminyltransferase). In mouse pancreatic cancer tumors, GCNT3 upregulation (103-fold; P < 0.0001) was correlated with increased expression of mucins (5 to 87-fold; P < 0.04-0.0003). Aberrant GCNT3 expression was also associated with increased mucin production, aggressive tumorigenesis, and reduced patient survival, and CRISPR-mediated knockout of GCNT3 in pancreatic cancer cells reduced proliferation and spheroid formation. Using in silico small molecular docking simulation approaches, we identified talniflumate as a novel inhibitor that selectively binds to GCNT3. In particular, docking predictions suggested that three notable hydrogen bonds between talniflumate and GCNT3 contribute to a docking affinity of À8.3 kcal/mol. Furthermore, talniflumate alone and in combination with low-dose gefitinib reduced GCNT3 expression, leading to the disrupted production of mucins in vivo and in vitro. Collectively, our findings suggest that targeting mucin biosynthesis through GCNT3 may improve drug responsiveness, warranting further development and investigation in preclinical models of pancreatic tumorigenesis.

Downregulation of N-Acetylglucosaminyltransferase GCNT3 by miR-302b-3p Decreases Non-Small Cell Lung Cancer (NSCLC) Cell Proliferation, Migration and Invasion

“…Abnormal expression of GCNT3 promotes the formation of mucins to enhance the flexibility of cancer cells and allow them to adapt to adverse tumor microenvironment conditions [9][10][11][12]. Analysis of clinical data from NSCLC patients and expression data from TCGA indicated that GCNT3 was up-regulated in NSCLC tissues and associated with TNM stage, lymph node metastasis and patients' OS (Table 1 and Fig.…”

“…Recent evidence has shown that GCNT3 promotes human tumorigenesis [9,10], and the EMT process has been confirmed to be an essential process for tumor invasion and metastasis [39]. E-cadherin [40], N-cadherin [41] and vimentin [42] have been identified as the main factors in the EMT process.…”

“…Recent research has shown that GCNT3 promotes human tumorigenesis. Rao et al (2016) reported that GCNT3 is significantly overexpressed in human pancreatic cancer, and high GCNT3 expression is associated with the smoking and drinking habits of patients, as well as a diagnosis of diabetes [10]. GCNT3 has also been found to be under-expressed in stage II colon tumors compared with human normal colon tissues [11].…”

Molecular Pathways: Mucins and Drug Delivery in Cancer

“…GCNT3 was significantly overexpressed in human pancreatic cancer and reduced patient survival by 7 months. High GCNT3 expression was also associated with patients’ drinking, smoking habits, and diabetes diagnosis (26). Aberrant GCNT3 expression was linked with increased mucin production, aggressive tumorigenesis, and reduced patient survival; CRISPR-mediated GCNT3 knockout in pancreatic cancer cells reduced proliferation and spheroid formation (26).…”

“…The core 2 beta 1,6 N-acetylglucosaminyltransferase (GCNT3/ C2GNT) plays a significant role in mucin glycan biosynthesis. Aberrant GCNT3 expression leads to mucin overexpression (23–26). GCNT3 activity plays an important role in physiological processes, including inflammatory and immune responses.…”