MicroRNA let-7d targets thrombospondin-1 and inhibits the activation of human pancreatic stellate cells

Hiroyuki Asama, Rei Suzuki, Takuto Hikichi, Tadayuki Takagi, Atsushi Masamune, Hiromasa Ohira

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


Objectives: The microRNA (miRNA) let-7d is linked to the formation of pancreatic cancer-related fibrosis. In this study, the mechanism by which let-7d regulates the activation of the human pancreatic stellate cell (hPSC) was evaluated. Methods: The transient transfection of a let-7d mimic in the hPSCs was performed, and the altered thrombospondin 1 (THBS1) expression was confirmed by western blotting and real-time qPCR. Targeting of the 3′-untranslated region (UTR) of THBS1 by let-7d was investigated by the luciferase assays. After hPSC transfection using THBS1 siRNA, the fibrosis markers (α-SMA and collagen 1A1) were evaluated by western blotting and real-time qPCR. The correlation between tumor fibrosis and let-7d or THBS1 was estimated using the data from The Cancer Genome Atlas project. Finally, the effects of genistein on the hPSCs were evaluated. Results: We found that a let-7d mimic inhibits THBS1 expression by targeting its 3′-UTR. THBS1 inhibition by siRNA inhibited hPSC activation. An in silico analysis revealed that let-7d and THBS1 expression are negatively correlated. Additionally, let-7d was negatively correlated with the stromal score, while THBS1 was positively correlated with this score. Genistein substantially induced let-7d and decreased the expression of fibrosis marker along with the inhibition of THBS1. Conclusions: Let-7d inhibited hPSC activation by targeting THBS1. Genistein induced the expression of let-7d and might modulate pancreatic fibrosis.

Original languageEnglish
Pages (from-to)196-203
Number of pages8
Issue number1
Publication statusPublished - 2019 Jan


  • Fibrosis
  • Genistein
  • Let-7d
  • Pancreatic cancer
  • Pancreatic stellate cell


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