PMID: 

Free Radic Res. 2019 Jul ;53(7):714-726. Epub 2019 Jul 3. PMID: 30947567

Abstract Title: 

Silibinin induced apoptosis of human epidermal cancer A431 cells by promoting mitochondrial NOS.

Abstract: 

The antitumor effects of silibinin are of increasing interest, though its mechanism is not yet clear. The goal of this study was to clarify the mechanism of silibinin-induced cell death in the A431 human epidermoid carcinoma cell line. We used a cell viability assay, flow cytometry, nitric oxide (NO) assay, and western blotting to examine relationships between silibinin, NO generation and apoptosis in A431 cells. Silibinin inhibited A431 cell growth in a dose-dependent manner, inducing mitochondrial damage, and apoptosis at a high dose. At the same time, high dose silibinin increased NO levels in A431 cells and the endothelial nitric oxide synthase (eNOS) inhibitor NG-nitro-L-arginine methylester (L-NAME) attenuated silibinin-induced cell growth inhibition. By western blotting, silibinin caused increased eNOS phosphorylation in the mitochondria. The AMP-activated protein kinase inhibitor compound C significantly decreased p-eNOS expression, while blocking eNOS did not affect p-AMPK levels, suggested that AMPK acted upstream of eNOS. This study showed that silibinin increased NO levels in A431 cells by activating the AMPK-eNOS pathway, leading to mitochondrial dysfunction and apoptosis. In this mechanism of action, mitochondrial eNOS played an important role. The results provided new understanding of the functions of intracellular NO.

read more

PMID: 

Molecules. 2019 Apr 19 ;24(8). Epub 2019 Apr 19. PMID: 31010153

Abstract Title: 

Silibinin Downregulates the NF-κB Pathway and NLRP1/NLRP3 Inflammasomes in Monocytes from Pregnant Women with Preeclampsia.

Abstract: 

Preeclampsia (PE) is a human pregnancy-specific syndrome with abnormal activation of cells from the innate immune system. The present study evaluated whether silibinin (SB) treatment of monocytes from preeclamptic women could modulate NLRP1 and NLRP3 inflammasomes as well as TLR4/NF-κB pathway activation. Peripheral blood monocytes from 20 preeclamptic and 20 normotensive (NT) pregnant women, as well as the THP-1 cell line, were cultured with or without monosodium urate (MSU) or SB.,,,,,,,,andgene expression by monocytes was analysed by quantitative real-time polymerase chain reaction (qPCR), while inflammatory cytokine production and p65NF-κB activity were determined by enzyme-linked immunosorbent assays (ELISAs). TLR4/MyD88/NF-κB and NLRP1/NLRP3 inflammasomes pathways in THP-1 cells were evaluated by flow cytometry and western blot respectively. Compared with NT women, monocytes from preeclamptic women showed The Ethics Committee of the Botucatu Medical School approved the study (protocol number 2.333.216)higher endogenous activation of NLRP1/NLRP3 inflammasomes and the TLR4/NF-κB pathway as well as higher gene and protein expression of IL-1β, IL-18 and TNF-α, and lower expression of IL-10. Monocyte stimulation with MSU increased inflammation-related genes as well as NF-κB activity. In vitro, SB treatment of monocytes from preeclamptic women reduced the basal activation of these cells by decreasing NLRP1/NLRP3 inflammasomes and p65NF-κB activity. THP-1 cells exhibited a similar immunological response profile to monocytes from preeclamptic women when cultured with or without MSU or SB. These results suggest uric acid participates in the systemic inflammatory response characteristic of preeclampsia and that in vitro SB treatment can modulate the sterile inflammation established in monocytes from preeclamptic women.

read more

PMID: 

Int J Mol Sci. 2019 May 3 ;20(9). Epub 2019 May 3. PMID: 31058823

Abstract Title: 

Silybin-Induced Apoptosis Occurs in Parallel to the Increase of Ceramides Synthesis and miRNAs Secretion in Human Hepatocarcinoma Cells.

Abstract: 

Silybin is a flavonolignan extracted from(milk thistle) with hepatoprotective, antioxidant, and anti-inflammatory activity. Several studies have shown that silybin is highly effective to prevent and treat different types of cancer and that its antitumor mechanisms involve the arrest of the cell cycle and/or apoptosis. An MTT assay was performed to study cell viability, lipid peroxidation, extracellular NO production, and scavenger enzyme activity were studied by Thiobarbituric Acid-Reactive Species (TBARS) assay, NO assay, and MnSOD assay, respectively. Cell cycle and apoptosis analysis were performed by FACS. miRNA profiling were evaluated by real time PCR. In this study, we demonstrated that Silybin induced growth inhibition blocking the Hepg2 cells in G1 phase of cell cycle and activating the process of programmed cell death. Moreover, the antiproliferative effects of silybin were paralleled by a strong increase of the number of ceramides involved in the modulation of miRNA secretion. In particular, after treatment with silybin, miR223-3p and miR16-5p were upregulated, while miR-92-3p was downregulated (

read more

PMID: 

J Cell Physiol. 2019 Dec ;234(12):22285-22298. Epub 2019 May 9. PMID: 31073992

Abstract Title: 

Silibinin encapsulation in polymersome: A promising anticancer nanoparticle for inducing apoptosis and decreasing the expression level of miR-125b/miR-182 in human breast cancer cells.

Abstract: 

Silibinin, a polyphenolic flavonolignan, is well-known as a safe therapeutic drug without any side effects in the treatment of many malignancies especially cancerous cells. In this study, to overcome problems such as low solubility of silibinin and to enhance its delivery to cancerous cells, we encapsulated silibinin in polymersome nanoparticles. Physicochemical measurements such as dynamic light scattering, transmission electron microscopy, scanning electron microscopy, and atomic force microscopy confirmed the proper encapsulation of silibinin in nanoparticles. Furthermore, antiproliferative and apoptotic activities of silibinin encapsulated in polymersome nanoparticles (SPNs) on MDA-MB-231 breast cancer cell line were validated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, Annexin V/Propidium Iodide measurement, and cell cycle analysis. In addition, quantitative reverse transcription polymerase chain reaction analysis confirmed that SPNs can repress oncogenic microRNAs (miRNAs) such as miR-125b andmiR-182, as well as antiapoptotic genes such as Bcl2. SPNs can also induce overexpression of proapoptotic target genes such as P53, CASP9, and BAX directly and/or indirectly (through regulation of miRNAs). Our results suggested that polymersomes can be used as stable carriers in nano-dimensions andSPNs can be considered as a promising pharmacological agent for cancer therapy.

read more

PMID: 

Arch Biochem Biophys. 2019 Aug 15 ;671:42-51. Epub 2019 May 11. PMID: 31085166

Abstract Title: 

Silibinin-induced apoptosis of breast cancer cells involves mitochondrial impairment.

Abstract: 

Mitochondria are dynamically regulated by fission and fusion processes. Silibinin induces apoptosis of MCF-7 and MDA-MB-231 human breast cancer cells. However, whether or not mitochondria dysfunction is involved in the apoptosis induction with silibinin of both types of the cells remains unknown. We here report that silibinin decreases the mitochondrial mass in terms of MitoTracker Green staining in both breast cancer cells. Silibinin induces morphological changes of mitochondria from oval to truncated or fragmented shapes accordingly. Condensed crests are observed in mitochondria by transmission electron microscopy. Silibinin causes mitochondrial membrane potential reduced. The expression of mitochondrial fission-associated proteins including dynamin-related protein 1 (DRP1) is up-regulated, whereas expression of the mitochondrial fusion-associated proteins, optic atrophy 1 and mitofusin 1, is down-regulated. In addition, silibinin treatment down-regulates ATP content as well as the levels of mitochondrial biogenesis-regulators including mitochondrial transcription factor A, peroxisome proliferator-activated receptor gamma coactivator 1 and nuclear respiratory factor 2. Moreover, treatments with DRP1 inhibitor, mdivi-1, or with DRP1-targetted siRNA efficiently prevent silibinin-induced apoptosis in the breast cancer cells, whereas inhibition of DRP1 phosphorylation with staurosporine increases apoptosis furthermore. Taken together, we conclude that silibinin impairs mitochondrial dynamics and biogenesis, leading to apoptosis of MCF-7 and MDA-MB-123 cells.

read more

PMID: 

J Physiol Sci. 2019 Jul ;69(4):643-652. Epub 2019 May 13. PMID: 31087219

Abstract Title: 

Natural silibinin modulates amyloid precursor protein processing and amyloid-β protein clearance in APP/PS1 mice.

Abstract: 

Silibinin has been shown to attenuate cognitive dysfunction and inhibit amyloid-beta (Aβ) aggregation in Alzheimer's disease (AD) models. However, the underlying mechanism by which silibinin improves cognition remains poorly understood. In this study, we investigated the effect of silibinin on β-secretase levels, Aβ enzymatic degradation, and oxidative stress in the brains of APP/PS1 mice with cognitive impairments. Oral administration of silibinin for 2 months significantly attenuated the cognitive deficits of APP/PS1 mice in the Y-maze test, novel object recognition test, and Morris water maze test. Biochemical analyses revealed that silibinin decreased Aβ deposition andthe levels of soluble Aβ1-40/1-42 in the hippocampus by downregulating APP and BACE1 and upregulating NEP in APP/PS1 mice. In addition, silibinin decreased the MDA content and increased the activities of the antioxidant enzymes CAT, SOD, and NO. Based on our findings, silibinin is a potentially promising agent for preventing AD-associated Aβ pathology.

read more

PMID: 

Neurochem Res. 2019 Aug ;44(8):1818-1829. Epub 2019 May 17. PMID: 31102026

Abstract Title: 

Silibinin Alleviates the Learning and Memory Defects in Overtrained Rats Accompanying Reduced Neuronal Apoptosis and Senescence.

Abstract: 

Excessive physical exercise (overtraining; OT) increases oxidative stress and induces damage in multiple organs including the brain, especially the hippocampus that plays an important role in learning and memory. Silibinin, a natural flavonoid derived from milk thistle of Silybum marianum, has been reported to exert neuroprotective effect. In this study, rats were subjected to overtraining exercise, and the protective effects of silibinin were investigated in these models. Morris water maze and novel object recognition tests showed that silibinin significantly attenuated memory defects in overtrained rats. At the same time, the results of Nissl, TUNEL and SA-β-gal staining showed that silibinin reversed neuronal loss caused by apoptosis, and delayed cell senescence of the hippocampus in the overtrained rats, respectively. In addition, silibinin decreased malondialdehyde (MDA) levels which is associated with reactive oxygen species (ROS) generation. Silibinin prevented impairment of learning and memory caused by excessive physical exercise in rats, accompanied by reduced apoptosis and senescence in hippocampus cells.

read more

PMID: 

Appl Microbiol Biotechnol. 2019 Sep ;103(17):7141-7149. Epub 2019 Jun 24. PMID: 31236617

Abstract Title: 

Regulation of gut microbiota in Alzheimer's disease mice by silibinin and silymarin and their pharmacological implications.

Abstract: 

The newly reported associations between Alzheimer's disease (AD) and gut microbiota indicate the potential of gut microbiota regulation-based therapeutic intervention for AD. Silymarin and its main active component, silibinin, are promising natural agents against AD, while their acting mechanisms remain to be explored. The present study investigated the effects of silibinin and silymarin administration on behavioral and histological manifestations, and regulation on the gut microbiota of transgenic APP/PS1 mice. First, silibinin and silymarin administration could alleviate memory deficits and reduce the amyloid plaque burden in the brain of APP/PS1 mice in comparison with controls. Second, silibinin and silymarin administration tended to decrease the microbiota diversity and exhibited regulative effect in abundances on several key bacterial species associated with AD development. This implied that gut microbiota regulation by silibinin and silymarin might be involved in their effects against AD. Further studies are warranted to fully elucidate the molecular mechanisms.

read more

PMID: 

Nutr Cancer. 2019 Jul 9:1-10. Epub 2019 Jul 9. PMID: 31287731

Abstract Title: 

Silibinin Differentially Decreases the Aggressive Cancer Phenotype in an In Vitro Model of Obesity and Prostate Cancer.

Abstract: 

: Obesity increases the risk for aggressive and fatal prostate cancer (PCa). The bioactive compound silibinin has been researched for its chemopreventative properties and may benefit obese or overweight individuals with PCa.: This study used anmodel of obesity exposing prostate cancer cells to sera from obese, overweight, or normal weight males with or without the addition of silibinin. Molecular activity was assayed as well as the phenotype of PCa cells with various treatments.: Obesity increased the expression of proliferative signaling including COX-2, IL-6, AKT, ERK, and AR, which was attenuated with silibinin. Cell growth, and invasive capacity of prostate cancer cells was increased with obese and overweight sera, and silibinin was able to mitigate this affect. However, there are limitations to this study in that anmodel was not used to validate theseresults nor a co-culture model, which may better recapitulate the tumor microenvironment.: Silibinin may be a safe intervention for those with or at risk for prostate cancer, and it may be the most beneficial for obese or overweight males.

read more

PMID: 

Pathol Res Pract. 2019 Sep ;215(9):152530. Epub 2019 Jul 11. PMID: 31351801

Abstract Title: 

Silibinin inhibited autophagy and mitochondrial apoptosis in pancreatic carcinoma by activating JNK/SAPK signaling.

Abstract: 

BACKGROUND: Previous investigation have indicated Silibinin induces apoptosis and JNK/SAPK in human pancreatic cancer cells. This study aims to evaluate the further mechanism of Silibinin in pancreatic cancer treatment.MATERIALS AND METHODS: Human pancreatic cancer cell lines SW1990 was treated with Silibinin and/or JNK/SAPK inhibitor SP600125 followed by measurement of cell viability, apoptosis, autophagy, ROS and ATP, and western blotting.RESULTS: Silibinin promoted cell viability and promoted cell apoptosis. The expression of ROS and ATP associated with mitochondrial function was also promoted by the treatment of silibinin. Silibinin also promoted autophagy in pancreatic cancer cells. All these biological effects of Silibinin can be reversed by JNK/SAPK inhibitor.CONCLUSIONS: The biological effects regulated by Silibinin can be mediated by JNK/SAPK signaling. This provides a solid theoretical basis for the role of Silibinin in the treatment of pancreatic cancer.

read more