m6A modified BACE1-AS contributes to liver metastasis and stemness-like properties in colorectal cancer through TUFT1 dependent activation of Wnt signaling

J Exp Clin Cancer Res. 2023 Nov 21;42(1):306. doi: 10.1186/s13046-023-02881-0.

Abstract

Background: Liver metastasis is one of the most important reasons for high mortality of colorectal cancer (CRC). Growing evidence illustrates that lncRNAs play a critical role in CRC liver metastasis. Here we described a novel function and mechanisms of BACE1-AS promoting CRC liver metastasis.

Methods: qRT-PCR and in situ hybridization were performed to examine the BACE1-AS level in CRC. IGF2BP2 binding to m6A motifs in BACE1-AS was determined by RIP assay and S1m-tagged immunoprecipitation. Transwell assay and liver metastasis mice model experiments were performed to examine the metastasis capabilities of BACE1-AS knockout cells. Stemness-like properties was examined by tumor sphere assay and the expression of stemness biomarkers. Microarray data were acquired to analyze the signaling pathways involved in BACE1-AS promoting CRC metastasis.

Results: BACE1-AS is the most up-regulated in metastatic CRC associated with unfavorable prognosis. Sequence blast revealed two m6A motifs in BACE1-AS. IGF2BP2 binding to these two m6A motifs is required for BACE1-AS boost in metastatic CRC. m6A modified BACE1-AS drives CRC cells migration and invasion and liver metastasis both in vitro and in vivo. Moreover, BACE1-AS maintains the stemness-like properties of CRC cells. Mechanically, BACE1-AS promoted TUFT1 expression by ceRNA network through miR-214-3p. CRC patients with such ceRNA network suffer poorer prognosis than ceRNA-negative patients. Depletion of TUFT1 mimics BACE1-AS loss. BACE1-AS activated Wnt signaling pathway in a TUFT1 dependent manner. BACE1-AS/miR-214-3p/TUFT1/Wnt signaling regulatory axis is essential for CRC liver metastasis. Pharmacologic inhibition of Wnt signaling pathway repressed liver metastasis and stemness-like features in BACE1-AS over-expressed CRC cells.

Conclusion: Our study demonstrated BACE1-AS as a novel target of IGF2BP2 through m6A modification. m6A modified BACE1-AS promotes CRC liver metastasis through TUFT1 dependent activation of Wnt signaling pathway. Thus, targeting BACE1-AS and its downstream Wnt signaling pathways may provide a new opportunity for metastatic CRC intervention and treatment.

Keywords: BACE1-AS; Colorectal cancer; Liver metastasis; TUFT1; m6A modification.

MeSH terms

  • Adenosine / analogs & derivatives
  • Amyloid Precursor Protein Secretases* / genetics
  • Aspartic Acid Endopeptidases / genetics
  • Cell Line, Tumor
  • Colorectal Neoplasms* / metabolism
  • Colorectal Neoplasms* / pathology
  • Dental Enamel Proteins* / metabolism
  • Humans
  • Liver Neoplasms* / secondary
  • RNA, Antisense* / metabolism
  • RNA-Binding Proteins / metabolism
  • Wnt Signaling Pathway

Substances

  • BACE1 protein, human
  • RNA, Antisense
  • Aspartic Acid Endopeptidases
  • Amyloid Precursor Protein Secretases
  • N-methyladenosine
  • Adenosine
  • IGF2BP2 protein, human
  • RNA-Binding Proteins
  • tuftelin
  • Dental Enamel Proteins