Regulation of PD-L1 expression by matrix stiffness in lung cancer cells

Ayako Miyazawa, Satoru Ito, Shuichi Asano, Ichidai Tanaka, Mitsuo Sato, Masashi Kondo, Yoshinori Hasegawa

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Expression of programmed death-ligand 1 (PD-L1) in tumor cells such as lung cancer cells plays an important role in mechanisms underlying evasion of an immune check point system. Lung cancer tissue with increased deposition of extracellular matrix is much stiffer than normal lung tissue. There is emerging evidence that the matrix stiffness of cancer tissue affects the phenotypes and properties of cancer cells. Nevertheless, the effects of substrate rigidity on expression of PD-L1 in lung cancer cells remain elusive. We evaluated the effects of substrate stiffness on PD-L1 expression in HCC827 lung adenocarcinoma cells by using polyacrylamide hydrogels with stiffnesses of 2 and 25 kPa. Expression of PD-L1 protein was higher on the stiffer substrates (25 kPa gel and plastic dish) than on the soft 2 kPa gel. PD-L1 expression was reduced by detachment of cells adhering to the substrate. Interferon-γ enhanced expression of PD-L1 protein cultured on stiff (25 kPa gel and plastic dishes) and soft (2 kPa gel) substrates and in the cell adhesion-free condition. As the stiffness of substrates increased, formation of actin stress fiber and cell growth were enhanced. Transfection of the cells with short interfering RNA for PD-L1 inhibited cell growth without affecting stress fiber formation. Treatment of the cells with cytochalasin D, an inhibitor of actin polymerization, significantly reduced PD-L1 protein levels. Taken together, a stiff substrate enhanced PD-L1 expression via actin-dependent mechanisms in lung cancer cells. It is suggested that stiffness as a tumor environment regulates PD-L1 expression, which leads to evasion of the immune system and tumor growth.

Original languageEnglish
Pages (from-to)2344-2349
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume495
Issue number3
DOIs
Publication statusPublished - 15-01-2018

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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