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MicroRNA-30b-5p functions as a metastasis suppressor in colorectal cancer by targeting Rap1b

Mengjing Fan1, Ximei Ma2, Feifan Wang3

  • 1Biomedical Research Center, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.

Cancer Letters
|March 1, 2020
PubMed

Insights

MicroRNA-30b-5p acts as a tumor suppressor in colorectal cancer liver metastasis (CRLM) by inhibiting cell invasion and migration. It targets Rap1b, a protein promoting cell adhesion and mobility, offering a potential therapeutic target for CRLM.

Area of Science:

  • Molecular Biology
  • Oncology
  • Cancer Metastasis Research

Background:

  • Colorectal liver metastasis (CRLM) is a primary cause of mortality in colorectal cancer (CRC) patients.
  • The precise role of microRNA-30b-5p (miR-30b-5p) in CRLM progression remains largely unelucidated.
  • MiR-30b-5p has demonstrated dual roles as an oncogene or tumor suppressor in various cancer types.

Purpose of the Study:

  • To investigate the functional role of miR-30b-5p in colorectal cancer liver metastasis.
  • To identify the molecular targets of miR-30b-5p involved in CRLM progression.
  • To evaluate the therapeutic potential of targeting the miR-30b-5p/Rap1b axis in CRLM.

Main Methods:

  • In vitro assays assessing cell invasion, migration, adhesion, and motility in CRC cell lines (HCT116, LoVo).
  • Western blot analysis to evaluate the expression of epithelial-mesenchymal transition (EMT) and adhesion-related proteins.
  • Validation of Rap1b as a direct target of miR-30b-5p using luciferase reporter assays and rescue experiments.
  • In vivo studies using mouse models to assess the effect of miR-30b-5p and Rap1b on CRLM.
  • Analysis of miR-30b-5p and Rap1b expression in clinical CRC and liver metastasis (LM) tissues.

Main Results:

  • Overexpression of miR-30b-5p significantly suppressed CRC cell invasion, migration, adhesion, and motility.
  • MiR-30b-5p downregulated EMT markers (Zeb1, Snail, vimentin) and adhesion-related proteins (p-paxillin, p-Src).
  • Rap1b was identified as a direct functional target of miR-30b-5p; its overexpression rescued miR-30b-5p-mediated suppression.
  • MiR-30b-5p overexpression inhibited CRLM in vivo, an effect attenuated by Rap1b rescue.
  • MiR-30b-5p was downregulated in clinical CRC and LM tissues, inversely correlated with Rap1b expression.

Conclusions:

  • MiR-30b-5p functions as a tumor suppressor in colorectal cancer liver metastasis by targeting Rap1b.
  • The miR-30b-5p/Rap1b pathway plays a critical role in regulating CRC cell adhesion, migration, and metastasis.
  • Targeting miR-30b-5p or its downstream effector Rap1b represents a promising therapeutic strategy for CRLM.
Keywords:
AdhesionColorectal liver metastasisInvasionMigrationMobility

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