GPR56 promotes proliferation of colorectal cancer cells and enhances metastasis via epithelial‑mesenchymal transition through PI3K/AKT signaling activation

Oncol Rep. 2018 Oct;40(4):1885-1896. doi: 10.3892/or.2018.6582. Epub 2018 Jul 20.

Abstract

G protein‑coupled receptor 56 (GPR56), a member of the orphan GPCR family, has been reported to be an oncogene in various malignancies. However, little is known regarding the detailed molecular mechanism of GPR56 in colorectal cancer (CRC). The present study aimed to detect the expression level and biological function of GPR56 in CRC. We examined the expression of GPR56 in CRC tissues and cell lines by quantitative real time (qRT)‑PCR, immunohistochemistry, and western blot analysis. The prognostic significance of GPR56 in CRC patients was evaluated by Kaplan‑Meier survival analysis. The influence of GPR56 on tumor cell proliferation (via Cell Counting Kit‑8, and a tumor formation assay in mice), apoptosis (flow cytometry), cell cycle distribution (flow cytometry) and migration (Transwell assay) was explored. We also investigated the underlying mechanism of GPR56 by western blot analysis. We found GPR56 expression was significantly upregulated in CRC tissues and cell lines compared to corresponding normal controls. Higher GPR56 expression in patients predicted poorer prognosis. Depletion of GPR56 markedly suppressed cell proliferation, migration, and invasion. GPR56 overexpression promoted CRC cell metastasis by expediting epithelial‑mesenchymal transition by activating PI3K/AKT signaling. In conclusion, GPR56 played an important role in CRC progression and may represent a new therapeutic target to reduce CRC metastasis.

MeSH terms

  • Aged
  • Animals
  • Apoptosis
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism
  • Case-Control Studies
  • Cell Cycle
  • Cell Movement*
  • Cell Proliferation*
  • Colorectal Neoplasms / genetics
  • Colorectal Neoplasms / metabolism
  • Colorectal Neoplasms / pathology*
  • Epithelial-Mesenchymal Transition*
  • Female
  • Follow-Up Studies
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Lymphatic Metastasis
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Neoplasm Invasiveness
  • Phosphatidylinositol 3-Kinases / genetics
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Prognosis
  • Proto-Oncogene Proteins c-akt / genetics
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Receptors, G-Protein-Coupled / genetics
  • Receptors, G-Protein-Coupled / metabolism*
  • Signal Transduction
  • Survival Rate
  • Tumor Cells, Cultured
  • Xenograft Model Antitumor Assays

Substances

  • ADGRG1 protein, human
  • Biomarkers, Tumor
  • Receptors, G-Protein-Coupled
  • Phosphatidylinositol 3-Kinases
  • AKT1 protein, human
  • Proto-Oncogene Proteins c-akt