Objective  To investigate the regulation of fibromodulin (FMOD) on proliferation, adhesion and migration of non-small cell lung cancer cell line H322, and discuss its action mechanism.

  Methods  H322 cells were randomly divided into control group, small interfering RNA (siRNA) silencing FMOD (FMOD siRNA) group and control siRNA (Con siRNA) group. FMOD siRNA and Con siRNA were transfected into H322 cells. The cell viability of each group was detected by CCK-8 method. The adhesion ability of cells was detected by fluorescein diacetate (FDA) fluorescent staining. The cell migration ability was detected by Transwell method. Real time-PCR was used to detect the mRNA expressions of Cyclin D1, intercellular adhesion molecule -1 （ICAM-1）, E-cadherin, FMOD, transforming growth factor-β (TGF-β), Smad2, Smad3, Smad4 and Smad7 in cells. The protein expressions of Cyclin D1, ICAM-1, E-cadherin, FMOD, TGF-β1, Smad2, Smad3, Smad4 and Smad7 were detected by Western blot.

  Results  Compared with the Con siRNA group, the cell viability, cell adhesion and migration ability of the FMOD siRNA group were decreased, and the difference was statistically significant (P<0.01). There was no significant difference between the control group and the Con siRNA group. Real time-PCR and Western blot results showed that the mRNA and protein expression levels of Cyclin D1, ICAM-1, TGF-β1, Smad2, Smad3 and Smad4 were decreased in FMOD siRNA group, compared with Con siRNA group, while the mRNA and protein expression levels of E-cadherin and Smad7 are elevated.

  Conclusion  Silencing of the FMOD gene significantly reduces the proliferation, adhesion and migration of H322 cells, which may be conducted by inhibiting the TGF-β/Smad signaling pathway.