Tumor suppressor role of miR-3622b-5p in ERBB2-positive cancer

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Mingjie Lu1, Tongshan Wang1, Mingfeng He2

  • 1Department of Oncology, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, PR China.

Oncotarget
|February 5, 2017
PubMed

Insights

MicroRNA-3622b-5p suppresses ERBB2-positive cancers by targeting ERBB2. This microRNA (miRNA) is downregulated in breast and gastric cancers, and its restoration enhances apoptosis and chemotherapy sensitivity.

Area of Science:

  • Oncology
  • Molecular Biology
  • Genetics

Background:

  • ERBB2 (Epidermal Growth Factor Receptor 2) amplification/overexpression is common in various carcinomas.
  • The precise mechanisms for ERBB2 downregulation in ERBB2-positive cancers are not fully understood.
  • MicroRNAs (miRNAs) play crucial roles in cancer development and progression.

Purpose of the Study:

  • To investigate the role of miR-3622b-5p in the regulation of ERBB2 in ERBB2-positive breast and gastric cancers.
  • To elucidate the molecular mechanism by which miR-3622b-5p affects ERBB2 expression and cancer cell behavior.
  • To assess the therapeutic potential of miR-3622b-5p in ERBB2-positive cancers.

Main Methods:

  • Luciferase reporter assays were used to validate ERBB2 as a direct target of miR-3622b-5p.
  • Expression levels of miR-3622b-5p and ERBB2 protein were analyzed in cancer cell lines and patient tissues.
  • Western blotting was employed to assess the impact of miR-3622b-5p on ERBB2 protein levels and downstream signaling pathways (mTORC1/S6).
  • Apoptosis assays and sensitivity tests with chemotherapeutic agents (cisplatin, 5-fluorouracil) were conducted.

Main Results:

  • ERBB2 was confirmed as a direct target of miR-3622b-5p.
  • Overexpression of miR-3622b-5p led to decreased ERBB2 protein levels, reduced mTORC1/S6 activation, and induced apoptosis in ERBB2-positive cancer cells.
  • MiR-3622b-5p was significantly downregulated in both breast and gastric cancer tissues, with a more pronounced decrease in ERBB2-positive tumors.
  • Restoration of miR-3622b-5p expression sensitized ERBB2-positive cancer cells to cisplatin and 5-fluorouracil, increasing their vulnerability to apoptosis.

Conclusions:

  • MiR-3622b-5p acts as a tumor suppressor in ERBB2-positive breast and gastric cancers by directly targeting ERBB2.
  • The miR-3622b-5p/ERBB2/mTORC1 signaling pathway is a critical regulator of proliferation and apoptosis in these cancers.
  • MiR-3622b-5p represents a potential therapeutic target for enhancing the efficacy of chemotherapy in ERBB2-positive cancers.
Keywords:
ERBB2apoptosiscancermiR-3622b-5pproliferation

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