Curcumin inhibits cell proliferation and migration in NSCLC through a synergistic effect on the TLR4/MyD88 and EGFR pathways

Oncol Rep. 2019 Nov;42(5):1843-1855. doi: 10.3892/or.2019.7278. Epub 2019 Aug 14.

Abstract

Despite the increasing number of available therapeutic methods, the prognosis of non‑small cell lung cancer (NSCLC) remains poor. Furthermore, side effects are an important limiting factor in the treatment of NSCLC. Therefore, developing an efficacious, safe, affordable and easily accessible chemotherapeutic agent is necessary for NSCLC treatment. As a natural chemical produced by Zingiberaceae plants, curcumin exerts distinct antitumor effects on several tumor types. In the present study, curcumin was observed to inhibit not only cell proliferation and cell cycle transition, but also cell migration in NSCLC, as determined by a series of experiments (such as MTS assay, colony formation assay, flow cytometric analysis, Transwell migration assay and western blotting). Mechanistically, curcumin induced G2/M phase arrest by controlling cell cycle‑ and epithelial‑mesenchymal transition (EMT)‑related checkpoints. Furthermore, curcumin significantly inhibited the expression of Toll‑like receptor 4 (TLR4)/MyD88 and EGFR in a dose‑ and time‑dependent manner. Conversely, EGF reversed the inhibitory action of curcumin on TLR4/MyD88. In clinical specimens, TLR4 and MyD88 were highly expressed in NSCLC tissues, and a significant positive association was observed between TLR4 and MyD88 expression. These data suggested that curcumin may control the EGFR and TLR4/MyD88 pathways to synergistically downregulate downstream cell cycle‑ and EMT‑related regulators, in order to block cell proliferation and metastasis in NSCLC. These findings provide evidence for the clinical application of curcumin.

MeSH terms

  • Adult
  • Antineoplastic Agents / pharmacology*
  • Carcinoma, Non-Small-Cell Lung / drug therapy
  • Carcinoma, Non-Small-Cell Lung / metabolism*
  • Cell Line, Tumor
  • Cell Movement / drug effects
  • Cell Proliferation / drug effects
  • Curcumin / pharmacology*
  • Dose-Response Relationship, Drug
  • Epithelial-Mesenchymal Transition / drug effects
  • ErbB Receptors
  • Female
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Lung Neoplasms / drug therapy
  • Lung Neoplasms / metabolism*
  • Male
  • Myeloid Differentiation Factor 88 / metabolism
  • Signal Transduction / drug effects*
  • Toll-Like Receptor 4 / metabolism

Substances

  • Antineoplastic Agents
  • MYD88 protein, human
  • Myeloid Differentiation Factor 88
  • TLR4 protein, human
  • Toll-Like Receptor 4
  • EGFR protein, human
  • ErbB Receptors
  • Curcumin