c-Myc shuttled by tumour-derived extracellular vesicles promotes lung bronchial cell proliferation through miR-19b and miR-92a

Cell Death Dis. 2019 Oct 7;10(10):759. doi: 10.1038/s41419-019-2003-5.

Abstract

Lung cancer causes approximately one fifth of all cancer deaths. Tumour cells actively communicate with the surrounding microenvironment to support malignant progression. Extracellular vesicles (EVs) play a pivotal role in intercellular communication and modulate recipient cells by delivering their contents, including proteins and nucleic acids such as microRNAs (miRNAs). We isolated EVs from the conditioned medium (CM) of human lung cancer cell lines and plasma of lung cancer patients and cancer-free smokers using an ultracentrifugation method. A significant increase in bronchial HBEC-KRASV12high cell proliferation, confirmed by cell cycle analysis, was observed after treatment with cancer-derived EVs. Lung cancer-derived EVs induced transcription of the pri-miR-92a gene, resulting in the overexpression of mature miR-19b and miR-92a in recipient bronchial cells. Modulation of these two miRNAs using miRNA mimics or inhibitors confirmed their ability to promote proliferation. In silico analysis and experimental validation showed that miR-19b and miR-92a impaired the TGF-beta (TGFB) pathway and identified TGFBRI and TGFBRII as target genes involved in EV-mediated bronchial cell proliferation. Interestingly, the oncoprotein c-Myc, a well-known miR-17-92 cluster activator, was detected only in the EVs derived from lung cancer patients and cell lines and was able to modulate the proliferation of HBEC-KRASV12high recipient cells. These data support the role of c-Myc shuttling in lung cancer-derived EVs in inducing the upregulation of onco-miR-19b and miR-92a expression with concomitant impairment of the TGFB signalling pathway in recipient cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Aged
  • Apoptosis / genetics
  • Cell Proliferation / genetics
  • Extracellular Vesicles / genetics
  • Female
  • Gene Expression Regulation, Neoplastic / genetics
  • Humans
  • Lung Neoplasms / diagnostic imaging
  • Lung Neoplasms / genetics*
  • Lung Neoplasms / pathology
  • Male
  • MicroRNAs / genetics*
  • Middle Aged
  • Proto-Oncogene Proteins c-myc / genetics*
  • Proto-Oncogene Proteins p21(ras) / genetics
  • Tomography, Emission-Computed
  • Transforming Growth Factor beta / genetics
  • Tumor Microenvironment / genetics

Substances

  • KRAS protein, human
  • MIRN19 microRNA, human
  • MIRN92 microRNA, human
  • MYC protein, human
  • MicroRNAs
  • Proto-Oncogene Proteins c-myc
  • Transforming Growth Factor beta
  • Proto-Oncogene Proteins p21(ras)