Tiliroside disrupted iron homeostasis and induced ferroptosis via directly targeting calpain-2 in pancreatic cancer cells

BACKGROUND

Tiliroside (TIL) is a flavonoid compound that exists in a variety of edible plants. These dietary plants are widely used as food and medicine to treat various diseases. However, the effect of TIL on pancreatic cancer (PC) and its underlying mechanisms are unclear.

PURPOSE

This study aims to reveal the anti-PC effect of TIL and clarify its mechanism.

METHODS

The inhibitory effects of TIL on PC growth were studied both in vitro and in vivo. Flow cytometry, transmission electron microscopy, immunofluorescence, biochemical analyses, RT-qPCR, genetic ablation, and western blotting were employed to evaluate ferroptosis, autophagy, and iron regulation. Additionally, RNA sequencing (RNA-seq), biomolecular layer interferometry (BLI), and molecular simulation analysis were combined to identify TIL molecular targets. The clinicopathological significance of Calpain-2 (CAPN2) was determined through immunohistochemistry (IHC) on a PC tissue microarray.

RESULTS

Herein, we showed that TIL was an effective anti-PC drug. CAPN2 was involved in the TIL - induced elevation of the labile iron pool (LIP) in PC cells. TIL directly bound to and inhibited CAPN2 activity, resulting in AKT deactivation and decreased expression of glucose transporters (GLUT1 and GLUT3) in PC cells. Consequently, TIL impaired ATP and NADPH generation, inducing autophagy and ROS production. The accumulation of TIL-induced ROS combined with LIP iron causes the Fenton reaction, leading to lipid peroxidation. Meanwhile, TIL-induced reduction of free iron ions promoted autophagic degradation of ferritin to regulate cellular iron homeostasis, which further exacerbated the death of PC cells by ferroptosis. As an extension of these in vitro findings, our murine xenograft study showed that TIL inhibited the growth of PANC-1 cells. Additionally, we showed that CAPN2 expression levels were related to clinical prognoses in PC patients.

CONCLUSION

We identify TIL as a potent bioactive inhibitor of CAPN2 and an anti-PC candidate of natural origin. These findings also highlight CAPN2 as a potential target for PC treatment.

Tiliroside attenuates acute kidney injury by inhibiting ferroptosis through the disruption of NRF2-KEAP1 interaction

BACKGROUND

Ferroptosis, an iron-dependent process that regulates cell death. Emerging evidences suggest that ferroptosis induces acute kidney injury (AKI) progression, and inhibiting ferroptosis provides an effect strategy for AKI treatment. The disruption of the NRF2-KEAP1 protein to protein interaction (PPI) induces NRF2 activation, which provides a promising strategy that can identify new ferroptosis inhibitors. A previous study revealed that tiliroside, a glycosidic flavonoid extracted from Edgeworthia chrysantha Lindl (buds), has anti-neuroinflammatory and neuroprotective effects via NRF2 activation. However, the mechanism through which tiliroside activates NRF2 is unknown, and it remains unclear whether it has protective effects against AKI.

PURPOSE

To investigate whether tiliroside has protective effects against AKI in mice and the associated mechanisms.

METHODS

Possible tiliroside substrates were analyzed using molecular docking. Cisplatin- and ischemia-reperfusion injury (IRI)-induced AKI mouse models and HK2 cells model were constructed to evaluate the protective effects of tiliroside. CRISPR/Cas9 mediated NRF2 knockout HK2 cells were used to verify whether NRF2 mediates tiliroside protective effects.

RESULTS

In vivo, our results showed that tiliroside treatment preserved kidney functions in AKI mice models, as showed by lower levels of serum creatinine (SCr), blood urea nitrogen (BUN), and renal injury markers, including neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule 1 (KIM1), compared with the mice in control groups. In vitro, tiliroside treatment greatly ameliorated cisplatin-induced ferroptosis through NRF2 activation in cultured HK2 cells, as evidenced by the protective effects of tiliroside being greatly blunted after the knockout of NRF2 in HK2 cells. Mechanistic studies indicated that tiliroside promoted NRF2/GPX4 pathway activation and ferroptosis inhibition, perhaps via the disruption of the NRF2-KEAP1 PPI.

CONCLUSION

Together, our results demonstrate that tiliroside may serve as a NRF2-KEAP1 PPI inhibitor and prevents ferroptosis-induced AKI, indicating its potential for clinical AKI treatment.

Tiliroside Protects against Lipopolysaccharide-Induced Acute Kidney Injury via Intrarenal Renin-Angiotensin System in Mice

Tiliroside, a natural flavonoid, has various biological activities and improves several inflammatory diseases in rodents. However, the effect of Tiliroside on lipopolysaccharide (LPS)-induced acute kidney injury (AKI) and the underlying mechanisms are still unclear. This study aimed to evaluate the potential renoprotective effect of Tiliroside on LPS-induced AKI in mice. Male C57BL/6 mice were intraperitoneally injected with LPS (a single dose, 3 mg/kg) with or without Tiliroside (50 or 200 mg/kg/day for 8 days). Tiliroside administration protected against LPS-induced AKI, as reflected by ameliorated renal dysfunction and histological alterations. LPS-stimulated renal expression of inflammatory cytokines, fibrosis markers, and kidney injury markers in mice was significantly abolished by Tiliroside. This flavonoid also stimulated autophagy flux but inhibited oxidative stress and tubular cell apoptosis in kidneys from LPS-injected mice. Mechanistically, our study showed the regulation of Tiliroside on the intrarenal renin-angiotensin system in LPS-induced AKI mice. Tiliroside treatment suppressed intrarenal AGT, Renin, ACE, and Ang II, but upregulated intrarenal ACE2 and Ang1-7, without affecting plasma Ang II and Ang1-7 levels. Collectively, our data highlight the renoprotective action of Tiliroside on LPS-induced AKI by suppressing inflammation, oxidative stress, and tubular cell apoptosis and activating autophagy flux via the shift towards the intrarenal ACE2/Ang1-7 axis and away from the intrarenal ACE/Ang II axis.

Effects of Tiliroside and Lisuride Co-Treatment on the PI3K/Akt Signal Pathway: Modulating Neuroinflammation and Apoptosis in Parkinson's Disease

Researchers are actively exploring potential bioactive compounds to enhance the effectiveness of Lisuride (Lis) in treating Parkinson's disease (PD) over the long term, aiming to mitigate the serious side effects associated with its extended use. A recent study found that combining the dietary flavonoid Tiliroside (Til) with Lis has potential anti-Parkinson's benefits. The study showed significant improvements in PD symptoms induced by 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) when Til and Lis were given together, based on various behavioral tests. This combined treatment significantly improved motor function and protected dopaminergic neurons in rats with PD induced by MPTP. It also activated important molecular pathways related to cell survival and apoptosis control, as indicated by the increased pAkt/Akt ratio. Til and Lis together increased B-cell lymphoma 2 (Bcl-2), decreased caspase 3 activity, and prevented brain cell decay. Co-administration also reduced tumor necrosis factor alpha (TNF-α) and Interleukin-1 (IL-1). Antioxidant markers such as superoxide dismutase (SOD), catalase, and reduced glutathione significantly improved compared to the MPTP-induced control group. This study shows that using Til and Lis together effectively treats MPTP-induced PD in rats, yielding results comparable to an 8 mg/kg dose of levodopa, highlighting their potential as promising Parkinson's treatments.

Tiliroside induces ferroptosis to repress the development of triple-negative breast cancer cells

Ferroptosis is a newly found form of non-apoptotic regulated cell death that is essential for the advancement of cancer. Tiliroside (Til), an effective natural flavonoid glycoside of oriental paperbush flower, has been explored as a potential anticancer agent in a few cancer types. However, it is unclear whether and how Til could promote the death of triple-negative breast cancer (TNBC) cells by inducing ferroptosis. Our study determined that Til induced cell death and attenuated cell proliferation in TNBC cells in vitro and in vivo with less toxicity for the first time. Functional assays showed that ferroptosis was the predominant form that contributed to Til-induced cell death of TNBC. Mechanistically, Til induces ferroptosis of TNBC cells via independent PUFA-PLS pathways but is closely involved in the Nrf2/HO-1 pathway. Silencing of HO-1 substantially abrogated the tumor-inhibiting effects of Til. In conclusion, our findings suggest that the natural product Til exerted its antitumor activity on TNBC by promoting ferroptosis, and the HO-1/SLC7A11 pathway plays an indispensable role in Til-induced ferroptotic cell death.

Tiliroside targets TBK1 to induce ferroptosis and sensitize hepatocellular carcinoma to sorafenib

BACKGROUND

Combination therapy with other antineoplastic agent is a favorable approach for targeting the molecules involved in sorafenib resistance.

PURPOSE

In the present study, we determined whether tiliroside, a natural flavonoid glycoside isolated from oriental paperbush flower, could improve the sensitivity of hepatocellular carcinoma (HCC) cells to sorafenib. Furthermore, we investigated the mechanisms and identified the potential drug targets of tiliroside.

METHODS

Synergy was performed using CalcuSyn. Transcriptomic studies were adopted to investigate whether tiliroside could induce ferroptosis and inhibit the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway in HCC cells. Ferroptosis was analyzed using western blotting, flow cytometry, and transmission electron microscopy. Immunofluorescence, co-immunoprecipitation, and Nrf2 knockdown or overexpression were performed to confirm the involvement of Nrf2 in tiliroside-induced ferroptosis. Additionally, molecular docking and biolayer interferometry-based measurements were used to confirm the direct target of tiliroside. Finally, subcutaneous xenograft and orthotopic xenograft tumors in nude mice were used to assess the effects of tiliroside in vivo.

RESULTS

Tiliroside significantly enhanced the anti-HCC activity of sorafenib without any discernible side effects. Moreover, the combination of tiliroside and sorafenib induced synergistic effects against HCC in vitro. The inhibitory effects of tiliroside on HCC were antagonized by N-acetylcysteine and the ferroptosis inhibitor liproxstatin-1. Studies on the mechanism of action revealed that tiliroside could directly bind to TANK-binding kinase 1 (TBK1) and inhibit its enzymatic activity. Inhibition of TBK1 by tiliroside decreased the phosphorylation of serine 349 on sequestosome-1 (p62) and the affinity of p62 for kelch like ECH-associated protein 1 (Keap1) and promoted Keap1-mediated Nrf2 ubiquitination and degradation. The downstream target proteins of Nrf2, including glutathione peroxidase 4, ferritin heavy chain 1, and glucose-6-phosphate dehydrogenase, demonstrated similar results to that of Nrf2 protein, inducing ferroptosis in tiliroside-treated HCC cells. We extended these findings in vivo and found that tiliroside inhibited the growth of HepG2 tumors in both subcutaneous xenograft and orthotopic xenograft tumor models of HCC.

CONCLUSION

Our findings imply that tiliroside is a potent TBK1 inhibitor and a candidate natural anti-cancer product that could function as a sensitizer of sorafenib in HCC treatment by targeting TBK1 to induce ferroptosis.

Tiliroside suppresses triple-negative breast cancer as a multifunctional CAXII inhibitor

Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer characterized by poor prognosis, early recurrence, and the lack of durable chemotherapy responses and specific targeted treatments. In this preclinical study, we examines Tiliroside (TS, C₃₀H₂₆O₁₃), as one of the major compounds of Tribulus terrestris L. which has been used as an alternative therapy in clinic practice of breast cancer treatment, for its therapeutic use in TNBC. The association between CAXII expression level and survival probability of TNBC patients, and the difference of CAXII expression level between TNBC and normal samples were evaluated by using publicly accessible databases. To determine the anticancer efficacy of TS on TNBC cells, cell proliferation, wound healing, cell invasion, and 3D spheroid formation assays were performed and excellent anticancer activities of TS were displayed. Mouse models further demonstrated that TS significantly reduced the tumor burden and improved survival rate. The properties of TS as a novel CAXII inhibitor have also been evaluated by CAXII activity assay, pHi, pHe and lactate level assay. Further RT-PCR and Caspase-3 activity analyses also revealed the positive regulating effects of TS on E2F1,3/Caspase-3 axis in TNBC cells cultured in 2D or 3D systems. The findings indicate that TS suppresses TNBC progression as a potential novel CAXII inhibitor in preclinical experiments, which warrants further investigation on its therapeutic implications.

Identification of plant metabolite classes from Waltheria Indica L. extracts regulating inflammatory immune responses via COX-2 inhibition

ETHNOPHARMACOLOGICAL RELEVANCE

Waltheria Indica L. is traditionally used in Africa, South America and Hawaii to treat pain, anemia, diarrhea, epilepsy and inflammatory related diseases.

AIM OF THE STUDY

This study aimed to identify extraction parameters to maximize tiliroside yield and to quantitative secondary metabolite composition of Waltheria Indica under various extraction conditions. The extracts were tested for COX-2 inhibition and their activity correlated with the type and quantity of the secondary metabolites. Insight was gained about how extraction parameters influence the extract composition and thus the COX-2 enzymatic inhibitory activity.

MATERIALS AND METHODS

Powdered leaves of Waltheria Indica were extracted using water, methanol, ethyl acetate and ethanol at different temperatures. Tiliroside was identified by HPLC-HRMS n and quantified using a tiliroside standard. The compound groups of the secondary metabolites were quantified by spectrometric methods. Inhibitory potential of different Waltheria extracts against the COX-2 enzyme was determined using a fluorometric COX-2 inhibition assay.

RESULTS

The molecule, tiliroside, exhibited a COX-2 inhibition of 10.4% starting at a concentration of 15 μM and increased in a dose dependent manner up to 51.2% at 150 μM. The ethanolic extract at 30 °C and the ethyl acetate extract at 90 °C inhibited COX-2 with 37.7% and 38.9%, while the methanolic and aqueous extract showed a lower inhibition of 21.9% and 9.2% respectively. The results concerning phenol, alkaloid and tiliroside concentration in the extracts showed no dependence on COX-2 inhibition. The extracts demonstrated a direct correlation of COX-2 inhibitory activity with their triterpenoid-/steroidal-saponin concentration. COX-2 inhibition increased linearly with the concentration of the saponins.

CONCLUSION

The data suggest that Waltheria Indica extracts inhibit the key inflammatory enzyme, COX-2, as a function of triterpenoid- and steroidal-saponin concentration and support the known efficacy of extracted Waltheria Indica leaves as a traditional treatment against inflammation related diseases.

Effect of Standardized Fractions and Tiliroside from Leaves of Tilia americana on Depression Tests in Mice

Depression affects more than 300 million people worldwide, represents one of the leading causes of disability worldwide. Depression treatment is based on the use of tricyclic antidepressants, selective serotonin reuptake inhibitors. These drugs, although clinically effective, have also been shown to have delayed onset activity and produce significant adverse side effects. Medicinal plants are presented as a source of study in the search for therapies. This study was aimed to assess the antidepressant effect (on forced swimming test -FST- and tail suspension test -TST-) of different fractions and tiliroside from Tilia americana. The organic fractions (FAC1-1, FAC1-2) and aqueous fractions (FAqC2-1, FAqC2-3) were obtained by column chromatography and the HPLC analysis allowed the standardization based on the concentration (mg/g) of several compounds: FAqC2-1 with tiliroside 20, quercitrin 41.7, and quercetin glucoside 73.8; FAqC2-3 with tiliroside 2.4, quercitrin 16.6 and 7-O-luteolin glucoside 35.9; FAC1-1 caffeic acid was quantified with 7.87 ; FAC1-2 with tiliroside 24.7 and quercitrin 19.8. Each fraction was tested in ICR mice at different dose in the FST and TST, as well as in the open field test (OFT); tiliroside was isolated and tested in such assays (at 0.05, 0.1, 0.5, and 1.0 mg/kg). All fractions were active, the better was FAC1-2, and induced a dose-dependent effect on FST with an ED₅₀= 2.59 mg/kg and Emax = 175.4 sec; with a sedative effect in OFT. Tiliroside with like-antidepressant activity, showed a dose-response behavior (ED₅₀= 0.04 mg/kg and Emax = 121.42 sec for FST; ED₅₀= 0.014 mg/kg and Emax = 78.28 sec for TST).

Flos Magnoliae Inhibits Chloride Secretion via ANO1 Inhibition in Calu-3 Cells

Flos Magnoliae (FM, Chinese name: Xin-yi) is an oriental medicinal herb commonly used for symptomatic relief from allergic rhinitis, sinusitis, and headache, including in traditional Chinese and Korean medicine formulations. FM inhibits histamine release from mast cells and cytokine secretion from T cells. However, the mechanism of action of FM on the anoctamin-1 (ANO1) ion channel, which is responsible for nasal hypersecretion in allergic rhinitis, has not been elucidated. Therefore, in this study, we investigated the effect of a 30% ethanolic extract of FM (FM_EtOH) and its chemical constituents on ANO1 activity. We used high-performance liquid chromatography analysis to identify five major chemical constituents of FM_EtOH: vanillic acid, tiliroside, eudesmin, magnolin, and fargesin. Using a conventional whole-cell patch clamp method, we found that FM_EtOH (30, 100, and 300[Formula: see text][Formula: see text]g/mL) and its chemical constituent tiliroside inhibited ANO1 activity in ANO1-overexpressing HEK293T cells. In addition, we found that the treatment of the airway epithelial cell line Calu-3 with interleukin 4 significantly increased Ca[Formula: see text] activated Cl[Formula: see text] current (I_CaCC), but not cystic fibrosis transmembrane conductance regulator (CFTR)-mediated chloride current (I_CFTR). FM_EtOH and tiliroside specifically inhibited I_CaCC. Thus, in this study, we identified a novel mechanism underlying the alleviation of allergic rhinitis by FM_EtOH. Our results indicate that FM_EtOH and its chemical constituent tiliroside are promising and potent agents for the prevention and treatment of allergic rhinitis.

Activation of Nrf2 Pathway Contributes to Neuroprotection by the Dietary Flavonoid Tiliroside

Hyperactivated microglia plays a key role in regulating neuroinflammatory responses which cause damage to neurons. In recent years, substantial attention has been paid in identifying new strategies to abrogate neuroinflammation. Tiliroside, a natural dietary glycosidic flavonoid, is known to inhibit neuroinflammation. This study was aimed at investigating the molecular mechanisms involved in the inhibition of neuroinflammation and neurotoxicity by tiliroside. The effects of tiliroside on Nrf2 and SIRT1 activities in BV2 microglia and HT22 hippocampal neurons were investigated using immunoblotting and DNA binding assays. The roles of Nrf2 and SIRT1 in the anti-inflammatory activity of tiliroside were further investigated using RNA interference experiments. HT22 neuronal viability was determined by XTT, calcium influx, DNA fragmentation assays. The effect of tiliroside on MAP2 protein expression in HT22 neurons was investigated using western blotting and immunofluorescence. We also studied the impact of tiliroside on DNA fragmentation and ROS generation in APPSwe-transfected 3D neuronal stem cells. Results show that tiliroside increased protein levels of Nrf2, HO-1 and NQO1, indicating an activation of the Nrf2 protective mechanisms in the microglia. Furthermore, transfection of BV2 cells with Nrf2 siRNA resulted in the loss of anti-inflammatory activity by tiliroside. Tiliroside reduced protein levels of acetylated-NF-κB-p65, and increased SIRT1 in LPS/IFNγ-activated BV2 microglia. RNAi experiments revealed that inhibition of neuroinflammation by tiliroside was not affected by silencing SIRT1 gene. Results of neurotoxicity experiments revealed that neuroinflammation-induced toxicity, DNA fragmentation, ROS generation and calcium accumulation in HT22 neurons were significantly reduced by tiliroside treatment. In addition, the compound also protected differentiated human neural progenitor cells by blocking ROS generation and DNA fragmentation. Overall, this study has established that tiliroside protected BV2 microglia from LPS/IFNγ-induced neuroinflammation and HT22 neuronal toxicity by targeting Nrf2 antioxidant mechanisms. The compound also produced inhibition of NF-κB acetylation through activation of SIRT1, as well as increasing SIRT1 activity in mouse hippocampal neurons. Results from this study have further established the mechanisms involved in the anti-neuroinflammatory and neuroprotective activities of tiliroside.

Isolation of natural products with anti-ageing activity from the fruits of Platanus orientalis

BACKGROUND

Ageing is defined as the time-dependent decline of functional capacity and stress resistance resulting in increased morbidity and mortality.

HYPOTHESIS/PURPOSE

Reportedly, these effects can be delayed by mild genetic or pharmacological activation of the main modules of the proteostasis network.

STUDY DESIGN-METHODS

By employing advanced phytochemical methods we isolated natural products from the fruits of Platanus orientalis and studied (via a bio-guided approach) their effects in Drosophila flies, as well as in normal human fibroblasts.

RESULTS

We report herein that dietary administration in Drosophila flies of a phenolics-enriched methanol extract from the fruits of Platanus orientalis exerted antioxidant effects; activated proteostatic mechanisms and mildly extended flies' longevity. We then isolated the two major compounds of the extract, namely Platanoside and Tiliroside and found that enrichment of the total extract with these compounds decreased oxidative stress and (in the case of the Tiliroside enriched extract) activated proteostatic mechanisms. Administration of purified Tiliroside in flies activated proteostatic genes, enhanced proteasome and lysosomal-cathepsin activities and decreased tissues' oxidative load; moreover, it delayed the rate of age-related decrease in flies' locomotion activity and increased flies' longevity. Notably, Tiliroside also activated proteasome in normal human fibroblasts and delayed progression of cellular senescence indicating that it may also impact on human cells rate of senescence.

CONCLUSION

Our presented findings highlight the potential anti-ageing activity of naturals products derived from the fruits of P. orientalis.

Antiprotozoal, Antibacterial and Antidiarrheal Properties from the Flowers of Chiranthodendron pentadactylon and Isolated Flavonoids

Background:

Chiranthodendron pentadactylon Larreat. (Sterculiaceae) is a Mexican plant used in traditional medicine for the treatment of heart disease symptoms and infectious diarrhea.

Objective:

To evaluate in vitro antiprotozoal and antibacterial activities and in vivo antidiarrheal activity from the flowers of C. pentadactylon using the extract, fractions, and major isolated flavonoids.

Materials and methods:

Bioassay-guided fractionation of the methanol extract of C. pentadactylon (MECP) led to the isolation of five flavonoids, tiliroside, astragalin, isoquercitrin, (+)-catechin, and (-)-epicatechin. Antimicrobial activities were tested on two protozoa (Entamoeba histolytica and Giardia lamblia) and nine bacterial enteropathogens (two Escherichia coli strains, two Shigella sonnei strains, two Shigella flexneri strains, two Salmonella sp. strains, and Vibrio cholerae) isolated from feces of children with acute diarrhea or dysentery and resistant to chloramphenicol. Also, antidiarrheal activity was tested on cholera toxin-induced diarrhea in male Balb-c mice.

Results:

Epicatechin was the most potent antiamoebic and antigiardial compound with IC₅₀ values of 1.9 μg/mL for E. histolytica and 1.6 μg/mL for G. lamblia; tiliroside showed moderate antiprotozoal activity against both protozoan. In contrast, in the antibacterial activity, tiliroside was the most potent compound on all microorganisms with minimum inhibitory concentration values less than 0.7 mg/mL. In the case of cholera toxin-induced diarrhea, epicatechin was the most potent flavonoid with IC₅₀ of 14.7 mg/kg.

Conclusion:

Epicatechin and tiliroside were the flavonoids responsible for antimicrobial andantidiarrheal activities of C. pentadactylon. Its antiprotozoal, antibacterial, and antidiarrheal properties are in good agreement with the traditional medicinal use of C. pentadactylon for the treatment of infectious diarrhea.

SUMMARY

Epicatechin was the most potent antiamoebic and antigiardial compound with IC₅₀ values of 1.9 μg/mL for E. histolytica and 1.6 μg/mL for G. lamblia.

Tiliroside showed antibacterial activity against all microorganisms tested with MIC values less than 0.7 mg/mL.

Epicatechin was the most potent flavonoid on cholera toxin-induced diarrhea with IC₅₀ of 14.7 mg/kg.

Abbreviations used: MECP: Methanol extract of C. pentadactylon