Anti-inflammatory Effects of Phyllanthus emblica L on Benzopyrene-Induced Precancerous Lung Lesion by Regulating the IL-1β/miR-101/Lin28B Signaling Pathway.

Phyllanthus emblica L (PEL), a well-known medical plant, has been used in Asian countries for a long time. Increasing evidence suggests that it can prevent the tumorigenesis of cancer associated with nonresolving inflammation. However, the possible anti-inflammatory mechanism responsible for preventing tumorigenesis of precancerous lung lesions is not well elucidated.

Male A/J mice were randomly divided into 5 groups with 10 mice in each group: (1) blank group (saline), (2) benzo(a)pyrene [B(a)P] group, (3) and (4) B(a)P + PEL (5 g/kg/d, 10 g/kg/d, administered by gavage), (5) B(a)P + celecoxib (30 mg/kg/d, administered by gavage). Nodes on the lung surface were observed and calculated. The levels of macrophage inflammatory protein (MIP-2), tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-1β were detected by enzyme-linked immunosorbent assay (ELISA) kits. Cyclo-oxygenase-2 (COX-2), hypoxia-inducible factor-1 (HIF-α), IL-1β, miR-101, and Lin28B protein levels were evaluated by immunohistochemistry and Western blotting.

PEL extract treatment significantly reduced the number of nodes on the lung surface and attenuated B(a)P-induced levels of proinflammatory cytokines MIP-2, TNF-α, IL-6, and IL-1β in lung tissue. The protein expressions of COX-2 and HIF-α were significantly decreased by the treatment of PEL. In addition, both PEL extract and celecoxib markedly upregulate the expression of miR-101 while downregulating IL-1β and Lin28B levels.

Our study indicated that treatment with PEL extract can not only protect the lung from inflammatory injury but effectively prevent precancerous lung lesions through regulating the IL-1β/miR-i101/Lin28B signaling pathway.