Limonium duriusculum (de Girard) Kuntze Exhibits Anti-inflammatory Effect Via NF-κ B Pathway Modulation

HIGHLIGHTS L. duriusculum n-BuOH extract reduces inflammatory responses both in vitro and in vivo. L. duriusculum n-BuOH extract inhibits NF-κB-dependent transcriptional responses. L. duriusculum n-BuOH extract decreases the expression of TNF-α and IL-6 genes.

Abstract Limonium duriusculum is used in folk medicine to treat inflammatory disorders and has gained attention due to its richness in apigenin. The present investigation was performed to evaluate and confirm its anti-inflammatory properties, in cell lines and animal models. The potential anti-inflammatory properties of n-butanol (n-BuOH) extract of L. duriusculum (BEL) and isolated apigenins were examined on NF-κB transcriptional activity in TNFα- or LPS-stimulated cells, and on in vivo acute inflammatory models (carrageenan induced paw edema and peritonitis). BEL treatment was able to inhibit the activity of an NF-κB reporter gene in HCT116 cells both in the absence and in the presence of exogenous TNFα, used as NF-κB pathway inducer. This anti-inflammatory effect was even more potent compared to Apigenin (APG1) and was confirmed using monocyte-derived THP-1 cells treated with LPS to stimulate NF-κB-dependent transcription of IL-6 and TNFα mRNAs. Apigenin7-O-β-(6''-methylglucuronide) (APG2) was instead inactive both in HCT116 and THP-1 cells. BEL (oral, 200 mg/kg) led to paw swelling inhibition, vascular permeability and peritoneal leukocyte and PN migration diminution. Apigenins (intraperitoneal, APG1, APG2: 20 mg/kg) also evoked a significant anti-edema effect, early vascular permeability and leukocyte influx reduction. Collectively, this study demonstrates for the first time the effectiveness of L. duriusculum to inhibit NF-κB-dependent transcriptional responses in HCT116 and THP-1 cells. In vivo studies also established that L. duriusculum possesses a potential anti-inflammatory effect, confirm its traditional, empirical use, that could be attributed to its richness in apigenin.

Fasting-mimicking diet and hormone therapy induce breast cancer regression.

Approximately 75% of all breast cancers express the oestrogen and/or progesterone receptors. Endocrine therapy is usually effective in these hormone-receptor-positive tumours, but primary and acquired resistance limits its long-term benefit1,2. Here we show that in mouse models of hormone-receptor-positive breast cancer, periodic fasting or a fasting-mimicking diet3-5 enhances the activity of the endocrine therapeutics tamoxifen and fulvestrant by lowering circulating IGF1, insulin and leptin and by inhibiting AKT-mTOR signalling via upregulation of EGR1 and PTEN. When fulvestrant is combined with palbociclib (a cyclin-dependent kinase 4/6 inhibitor), adding periodic cycles of a fasting-mimicking diet promotes long-lasting tumour regression and reverts acquired resistance to drug treatment. Moreover, both fasting and a fasting-mimicking diet prevent tamoxifen-induced endometrial hyperplasia. In patients with hormone-receptor-positive breast cancer receiving oestrogen therapy, cycles of a fasting-mimicking diet cause metabolic changes analogous to those observed in mice, including reduced levels of insulin, leptin and IGF1, with the last two remaining low for extended periods. In mice, these long-lasting effects are associated with long-term anti-cancer activity. These results support further clinical studies of a fasting-mimicking diet as an adjuvant to oestrogen therapy in hormone-receptor-positive breast cancer.

Dihydrotanshinone-I interferes with the RNA-binding activity of HuR affecting its post-transcriptional function.

Post-transcriptional regulation is an essential determinant of gene expression programs in physiological and pathological conditions. HuR is a RNA-binding protein that orchestrates the stabilization and translation of mRNAs, critical in inflammation and tumor progression, including tumor necrosis factor-alpha (TNF). We identified the low molecular weight compound 15,16-dihydrotanshinone-I (DHTS), well known in traditional Chinese medicine practice, through a validated high throughput screening on a set of anti-inflammatory agents for its ability to prevent HuR:RNA complex formation. We found that DHTS interferes with the association step between HuR and the RNA with an equilibrium dissociation constant in the nanomolar range in vitro (Ki = 3.74 ± 1.63 nM). In breast cancer cell lines, short term exposure to DHTS influences mRNA stability and translational efficiency of TNF in a HuR-dependent manner and also other functional readouts of its post-transcriptional control, such as the stability of selected pre-mRNAs. Importantly, we show that migration and sensitivity of breast cancer cells to DHTS are modulated by HuR expression, indicating that HuR is among the preferential intracellular targets of DHTS. Here, we disclose a previously unrecognized molecular mechanism exerted by DHTS, opening new perspectives to therapeutically target the HuR mediated, post-transcriptional control in inflammation and cancer cells.