Inhibition of formyl peptide receptor 1 activity suppresses tumorigenicity in vivo and attenuates the invasion and migration of lung adenocarcinoma cells under hypoxic conditions in vitro

SIRT3 Regulates the ROS-FPR1/HIF-1α Axis under Hypoxic Conditions to Influence Lung Cancer Progression

Hypoxia-inducible factor (HIF-1α) is a therapeutic target in lung cancer, and the deacetylase sirtuin 3 (SIRT3) is closely associated with tumorigenesis. Formyl peptide receptor 1 (FPR1) is involved in a wide range of physiopathological processes in various tumor cells. We explored whether SIRT3 affects the development of lung cancer by regulating the reactive oxygen species (ROS)-FPR1/HIF-1α axis under hypoxic conditions. The effects of SIRT3 overexpression on the levels of FPR1, HIF-1α, ROS, inflammatory factors, and cell proliferation and migration in A549 cells under hypoxic conditions were assessed in combination with the FPR1 inhibitor. BALB/c nude mice were subcutaneously injected with cancer cells transfected/untransfected with SIRT3 overexpressing lentiviral vectors. Immunohistochemistry and enzyme-linked immunosorbent assay were performed to detect SIRT3 expression and the expression levels of IL-1β, TNF-α, and IL-6, respectively, in tumor tissues. Cell proliferation, invasion, migration, and IL-1β, TNF-α, IL-6, and ROS levels were significantly higher in the Hypoxia group than in the Control group. Moreover, the mRNA and protein expression levels of SIRT3 were significantly down-regulated, whereas they were significantly up-regulated for FPR1 and HIF-1α. In contrast, SIRT3 overexpression in a hypoxic environment inhibited cell proliferation, invasion, and migration, decreased IL-1β, TNF-α, IL-6, and ROS levels, up-regulated the mRNA and protein expression levels of SIRT3, and down-regulated the mRNA and protein expression levels of FPR1 and HIF-1α. In addition, we found the same results in tumorigenic experiments in nude mice. SIRT3 in hypoxic environments may affect tumor cell proliferation, invasion, migration, and inflammation levels via the ROS-FPR1/HIF-1α axis, thereby inhibiting tumor cell development.

Annexin-A1; the culprit or the solution?

Annexin‐A1 has a well‐defined anti‐inflammatory role in the innate immune system, but its function in adaptive immunity remains controversial. This glucocorticoid‐induced protein has been implicated in a range of inflammatory conditions and cancers, as well as being found to be overexpressed on the T cells of patients with autoimmune disease. Moreover, the formyl peptide family of receptors, through which annexin‐A1 primarily signals, has also been implicated in these diseases. In contrast, treatment with recombinant annexin‐A1 peptides resulted in suppression of inflammatory processes in murine models of inflammation. This review will focus on what is currently known about annexin‐A1 in health and disease and discuss the potential of this protein as a biomarker and therapeutic target.