Semi-Synthesis of Flavonoid Glycosides and Their Anti-Inflammatory and Antitumor Activities towards Triple Negative Breast Cancer.

BACKGROUND: Flavonoid glycosides are known to possess diverse bioactivities including antitumor and anti-inflammatory properties. Hesperetin is abundant in nature and can be used to synthesize bioactive flavonoids. This has the advantages of low cost, short synthetic steps, simple operation, and good yields. OBJECTIVE: In this study, we aimed to synthesize bioactive flavonoids and flavonoid glycosides from hesperetin and evaluate the antitumor and anti-inflammatory activities of these compounds. METHODS: A series of flavonoids and their derivatives were synthesized by methoxylation, oxidative dehydrogenation, benzylation, debenzylation, and deacetylation as well as using a modified peroxyacetone method and a glycoside condensation reaction. Their anti-inflammatory activities were evaluated for their inhibitory effects on nitric oxide (NO), tumor necrosis factor (TNF-α), and interleukin-6 (IL-6) production in LPS-induced RAW264.7 mouse macrophages. Their structures were characterized by HRMS, 1 H-NMR, and 13 C-NMR, and their cytotoxicity on the human triple-negative breast cancer cell (TNBC) line, SUM 149, was tested by using the MST assay. RESULTS: Most of the compounds markedly reduced NO production in LPS-stimulated murine macrophages at the tested concentrations in a dose-dependent manner. Among these, compounds 1, 7, 9, and 17 showed significant anti-inflammatory activities against NO production in LPS-induced RAW264.7 mouse macrophages. In addition, they could also reduce the release of TNF-α and IL-6 in a concentration-dependent manner. Most of the tested compounds showed remarkable anti-human TNBC activities. Compounds 1b-1m, 1, and 3 showed a certain degree of growth inhibition effect on the human TNBC cell lines and their IC50 values were all below 16.61 µM. In addition, compound 1l was the most cytotoxic with IC50 values of 1.38±0.31 µM, while the other compounds were inactive with inhibition rates <50 % at the highest concentration tested (20 µM). CONCLUSIONS: A novel series of flavonoids were synthesized from the natural flavonoid, hesperetin, including 17 new compounds. Screening tests indicated that most of these compounds reduced NO production in LPS-stimulated murine macrophages at concentrations of 15 to 60 µM, and the inhibition generally increased in a dose-dependent manner. Some compounds showed different degrees of cytotoxicity on the human TBNC cell lines, SUM 149.

Lanostane-type triterpenoids from Ganoderma applanatum and their inhibitory activities on NO production in LPS-induced BV-2 cells.

Five previously undescribed lanostane-type triterpenoids, including two triterpenoids with a rearranged side chain (applanoic acids E and F), one C21 nortriterpenoid (16,17-dehydroapplanone E), as well as two highly oxygenated lanostane triterpenoids (methyl applaniate B and applanoic acid G), were isolated from the fruiting bodies of Ganoderma applanatum (Pers.) Pat. Their structures were elucidated on the basis of spectroscopic analysis, X-ray crystallography and ECD data. Applanoic acid E, 16,17-dehydroapplanone E, and methyl applaniate B showed inhibitory effects on the release of NO by LPS-induced BV-2 cells.

Geranylgeranyl transferase 1 inhibitor GGTI­298 enhances the anticancer effect of gefitinib.

Dysregulation of epidermal growth factor receptor (EGFR) signaling is responsible for the resistance to EGFR tyrosine kinase inhibitors (TKIs), such as gefitinib and erlotinib, and is thereby associated with the progression of tumors in non­small cell lung cancers (NSCLCs). Immunoblotting results revealed that geranylgeranyl transferase 1 inhibitor (GGTI)­298, a geranylgeranyl transferase 1 inhibitor with potential antitumor effects, effectively inhibited the phosphorylation of EGFR and its downstream target protein kinase B (AKT). A combination of gefitinib and GGTI­298 amplified the inhibition of the EGFR­AKT signaling pathway. In addition, GGTI­298 treatment produced a synergistic effect on the inhibition of proliferation as indicated by the combination index values of <1 when combined with gefitinib in the NSCLC cell lines HCC827 and A549. These synergistic effects were also observed to induce apoptosis and migration inhibition. Further mechanistic studies demonstrated that GGTI­298 inhibited the activity of Ras homolog family member A (RhoA), and downregulation of RhoA with small interfering RNA impaired the phosphorylation of EGFR, which suggested that EGFR inhibition by GGTI­298 may be exerted mainly through RhoA mediation. These results presented a novel, promising therapeutic strategy involving a combination of two drugs for targeting EGFR signaling in lung cancer.