Heterocyclic-Modified Imidazoquinoline Derivatives: Selective TLR7 Agonist Regulates Tumor Microenvironment against Melanoma.

Immunotherapy targeting the toll-like receptor 7 (TLR7) is a promising strategy for cancer treatment. Herein, we describe the design and synthesis of a series of imidazoquinoline-based TLR7 agonists and assess NF-κB pathway activation using HEK-Blue hTLR7 cells to identify the most potent small-molecule TLR7 agonist, SMU-L11 (EC50 = 0.024 ± 0.002 µM). In vitro experiments demonstrated that SMU-L11 specifically activated TLR7, resulting in recruitment of the MyD88 adaptor protein and activation of the NF-κB and MAPK signaling pathways. Moreover, SMU-L11 was found to exert immune-enhancing effects by significantly inducing the secretion of proinflammatory cytokines in murine dendritic cells, macrophages, and human peripheral blood mononuclear cells while promoting M1 macrophage polarization. In vivo studies using a B16-F10 mouse tumor model showed that SMU-L11 significantly enhanced immune cell activation and augmented CD4+ T and CD8+ T-cell proliferation, directly killing tumor cells and inhibiting tumor growth.

Design, synthesis and bioactivity evaluation of a series of quinazolinone derivatives as potent PI3Kγ antagonist.

Targeting PI3Kγ would be a useful strategy for treating inflammatory and cancer diseases. However, the development of selective inhibitors of PI3Kγ is very challenging due to the high structural and sequence homology with other PI3K isoforms. A series of quinazolinone derivatives were designed, synthesized and biologically evaluated as PI3Kγ-selective inhibitors. Among all the 28 compounds, compound 9b was found to be the most potent selective inhibitor with IC50 values of 13.11 nM against PI3Kγ kinase. Additionally, compound 9b could generate toxicity on leukemia cells in a panel of 12 different of cancer cell lines with the IC50 value of 2.41 ± 0.11 µM on Jurkat cell. Preliminary mechanism studies indicated that compound 9b through inhibit the activity of PI3K-AKT in human and murine leukemia cells, and activated phosphorylated p38 and phosphorylated ERK presented potent antiproliferative activity, which provided a potent small molecule for further cancer therapy.