The differential distributions of ASPM isoforms and their roles in Wnt signaling, cell cycle progression, and pancreatic cancer prognosis

Chung Chi Hsu, Wen Ying Liao, Tze Sian Chan, Wei Yu Chen, Chung Ta Lee, Yan Shen Shan, Po Jui Huang, Ya Chin Hou, Chi Rong Li, Kelvin K. Tsai

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive and treatment-resistant malignancy. The lack of pathway-informed biomarkers hampers the development of rational diagnostics or therapies. Recently, the protein abnormal spindle-like microcephaly-associated (ASPM) was identified as a novel Wnt and stemness regulator in PDAC, while the pathogenic roles of its protein isoforms remain unclarified. We developed novel isoform-specific antibodies and genetic knockdown (KD) of putative ASPM isoforms, whereby we uncovered that the levels of ASPM isoform 1 (iI) and ASPM-iII are variably upregulated in PDAC cells. ASPM isoforms show remarkably different subcellular locations; specifically, ASPM-iI is exclusively localized to the cortical cytoplasm of PDAC cells, while ASPM-iII is predominantly expressed in cell nuclei. Mechanistically, ASPM-iI co-localizes with disheveled-2 and active β-catenin as well as the stemness marker aldehyde dehydrogenase-1 (ALDH-1), and its expression is indispensable for the Wnt activity, stemness, and the tumorigenicity of PDAC cells. By contrast, ASPM-iII selectively regulates the expression level of cyclin E and cell cycle progression in PDAC cells. The expression of ASPM-iI and ASPM-iII displays considerable intratumoral heterogeneity in PDAC tissues and only that of ASPM-iI was prognostically significant; it outperformed ALDH-1 staining and clinico-pathological variables in a multivariant analysis. Collectively, the distinct expression patterns and biological functions of ASPM isoforms may illuminate novel molecular mechanisms and prognosticators in PDAC and may pave the way for the development of therapies targeting this novel oncoprotein.

Original languageEnglish
Pages (from-to)498-508
Number of pages11
JournalJournal of Pathology
Volume249
Issue number4
DOIs
Publication statusPublished - Dec 1 2019

Keywords

  • ASPM
  • cell cycle
  • isoform
  • pancreatic cancer
  • stemness
  • Wnt

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

Fingerprint Dive into the research topics of 'The differential distributions of ASPM isoforms and their roles in Wnt signaling, cell cycle progression, and pancreatic cancer prognosis'. Together they form a unique fingerprint.

  • Cite this