Silibinin suppresses PMA-induced MMP-9 expression by blocking the AP-1 activation via MAPK signaling pathways in MCF-7 human breast carcinoma cells

Silybin-Functionalized PCL Electrospun Fibrous Membranes for Potential Pharmaceutical and Biomedical Applications

Silybin is a natural flavonolignan with potential anticancer, antioxidant, and hepatoprotective properties. In the present study, various loadings of silybin (1, 3, and 5 wt%) were encapsulated in poly-ε-caprolactone (PCL) fibers by electrospinning, in order to produce new pharmaceutical composites with improved bioactive and drug delivery properties. The morphological characteristics of the composite fibrous structures were evaluated by scanning electron microscopy (SEM), and the encapsulation efficiency and the release rate of silybin were quantified using a UV-Vis spectrophotometer. The analysis of the membranes' thermal behavior by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) revealed the existence of interaction between PCL and silybin. An investigation of the cytocompatibility of the composite membranes revealed that normal cells displayed an unimpeded proliferation in the respective silybin concentrations; however, tumor cell growth demonstrated a dose-dependent inhibition. Furthermore, an effective antioxidant activity against hydrogen peroxide-induced oxidative stress in HEK-293 cells was observed for the prepared electrospun fibrous mats.

A comprehensive evaluation of the therapeutic potential of silibinin: a ray of hope in cancer treatment

Natural compounds hold promise in the search for cancer therapies due to their unique chemical structures and combinations that may effectively combat cancer while minimizing toxicity and side effects compared to conventional treatments. Silibinin, a natural lignan, has been found to possess strong anti-cancer activity against several types of human cancers based on emerging research. This study aims to provide an overview of the therapeutic potential of silibinin in the treatment and prevention of cancers. A comprehensive search was conducted using various internet databases such as PubMed, Google Scholar, and ScienceDirect to identify relevant research papers. Silibinin has been shown to exhibit anticancer activity against several types of cancers, including liver, lungs, breast, prostate, colorectal, skin, and bladder cancers. Its multifaceted mechanisms of action contribute to its therapeutic effects. Silibinin exerts antioxidant, anti-inflammatory, anti-proliferative, pro-apoptotic, anti-metastatic, and anti-angiogenic activities, making it a promising candidate for cancer therapy. One of the key mechanisms underlying the anticancer effects of silibinin is its ability to modulate multiple signaling pathways involved in cancer development and progression. It can inhibit the activation of various oncogenic pathways, including PI3K/Akt, NF-κB, Wnt/β-catenin, and MAPK pathways, thereby suppressing cancer cell proliferation, inducing cell cycle arrest, and promoting apoptosis. Silibinin possesses great potential as an effective treatment agent for cancer. The multifaceted mechanisms of action, favorable safety profile, and potential synergistic effects of silibinin with conventional therapies make it an attractive candidate for further investigation and development as a cancer treatment. However, more extensive clinical studies are necessary to fully establish the efficacy, optimal dosage, and long-term effects of silibinin in cancer treatment.

Updates on the Pivotal Roles of Mitochondria in Urothelial Carcinoma

Mitochondria are important organelles responsible for energy production, redox homeostasis, oncogenic signaling, cell death, and apoptosis. Deregulated mitochondrial metabolism and biogenesis are often observed during cancer development and progression. Reports have described the crucial roles of mitochondria in urothelial carcinoma (UC), which is a major global health challenge. This review focuses on research advances in the role of mitochondria in UC. Here, we discuss the pathogenic roles of mitochondria in UC and update the mitochondria-targeted therapies. We aim to offer a better understanding of the mitochondria-modulated pathogenesis of UC and hope that this review will allow the development of novel mitochondria-targeted therapies.

Mechanistic Insights into the Pharmacological Significance of Silymarin

Medicinal plants are considered the reservoir of diverse therapeutic agents and have been traditionally employed worldwide to heal various ailments for several decades. Silymarin is a plant-derived mixture of polyphenolic flavonoids originating from the fruits and akenes of Silybum marianum and contains three flavonolignans, silibinins (silybins), silychristin and silydianin, along with taxifolin. Silybins are the major constituents in silymarin with almost 70–80% abundance and are accountable for most of the observed therapeutic activity. Silymarin has also been acknowledged from the ancient period and is utilized in European and Asian systems of traditional medicine for treating various liver disorders. The contemporary literature reveals that silymarin is employed significantly as a neuroprotective, hepatoprotective, cardioprotective, antioxidant, anti-cancer, anti-diabetic, anti-viral, anti-hypertensive, immunomodulator, anti-inflammatory, photoprotective and detoxification agent by targeting various cellular and molecular pathways, including MAPK, mTOR, β-catenin and Akt, different receptors and growth factors, as well as inhibiting numerous enzymes and the gene expression of several apoptotic proteins and inflammatory cytokines. Therefore, the current review aims to recapitulate and update the existing knowledge regarding the pharmacological potential of silymarin as evidenced by vast cellular, animal, and clinical studies, with a particular emphasis on its mechanisms of action.

Novel molecules as the emerging trends in cancer treatment: an update

As per World Health Organization cancer remains as a leading killer disease causing nearly 10 million deaths in 2020. Since the burden of cancer increases worldwide, warranting an urgent search for anti-cancer compounds from natural sources. Secondary metabolites from plants, marine organisms exhibit a novel chemical and structural diversity holding a great promise as therapeutics in cancer treatment. These natural metabolites target only the cancer cells and the normal healthy cells are left unharmed. In the emerging trends of cancer treatment, the natural bioactive compounds have long become a part of cancer chemotherapy. In this review, we have tried to compile about eight bioactive compounds from plant origin viz. combretastatin, ginsenoside, lycopene, quercetin, resveratrol, silymarin, sulforaphane and withaferin A, four marine-derived compounds viz. bryostatins, dolastatins, eribulin, plitidepsin and three microorganisms viz. Clostridium, Mycobacterium bovis and Streptococcus pyogenes with their well-established anticancer potential, mechanism of action and clinical establishments are presented.

Bruton's agammaglobulinemia tyrosine kinase (Btk) regulates TPA‑induced breast cancer cell invasion via PLCγ2/PKCβ/NF‑κB/AP‑1‑dependent matrix metalloproteinase‑9 activation

Bruton's agammaglobulinemia tyrosine kinase (BTK) is an important cytoplasmic tyrosine kinase involved in B-lymphocyte development, differentiation, and signaling. Activated protein kinase C (PKC), in turn, induces the activation of mitogen-activated protein kinase (MAPK) signaling, which promotes cell proliferation, viability, apoptosis, and metastasis. This effect is associated with nuclear factor-κB (NF-κB) activation, suggesting an anti-metastatic effect of BTK inhibitors on MCF-7 cells that leads to the downregulation of matrix metalloproteinase (MMP)-9 expression. However, the effect of BTK on breast cancer metastasis is unknown. In this study, the anti-metastatic activity of BTK inhibitors was examined in MCF-7 cells focusing on MMP-9 expression in 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated MCF-7 cells. The expression and activity of MMP-9 in MCF-7 cells were investigated using quantitative polymerase chain reaction analysis, western blotting, and zymography. Cell invasion and migration were investigated using the Matrigel invasion and cell migration assays. BTK inhibitors [ibrutinib (10 µM), CNX-774 (10 µM)] significantly attenuated TPA-induced cell invasion and migration in MCF-7 cells and inhibited the activation of the phospholipase Cγ2/PKCβ signaling pathways. In addition, small interfering RNA specific for BTK suppressed MMP-9 expression and cell metastasis. Collectively, results of the present study indicated that BTK suppressed TPA-induced MMP-9 expression and cell invasion/migration by activating the MAPK or IκB kinase/NF-κB/activator protein-1 pathway. The results clarify the mechanism of action of BTK in cancer cell metastasis by regulating MMP-9 expression in MCF-7 cells.

Potential Role of Phytochemicals Against Matrix Metalloproteinase Induced Breast Cancer; An Explanatory Review

World Health Organization (WHO) estimated breast cancer as one of the most prevailed malignancy around the globe. Its incident cases are gradually increasing every year, resulting in considerable healthcare burden. The heterogeneity of breast cancer accounts for its differential molecular subtyping, interaction between pathways, DNA damaging, and chronic inflammation. Matrix metalloproteinases (MMPs) are a group of zinc-containing, calcium dependent endopeptidases which play a substantial role in breast carcinogenesis through several mechanisms. These mechanisms include remodeling of extracellular matrix (ECM), cell proliferation, and angiogenesis which promote metastasis and result in tumor progression. In this context, compounds bearing MMP inhibitory potential can serve as potent therapeutic agents in combating MMPs provoked breast cancer. Current systematic review aimed to encompass the details of potent natural lead molecules that can deter MMPs-provoked breast cancer. Following the critical appraisal of literature, a total of n = 44 studies that explored inhibitory effect of phytochemicals on MMPs were included in this review. These phytoconstituents include alkaloids (n = 11), flavonoids (n = 23), terpenoids (n = 7), and lignans (n = 2). The most common inhibitory methods used to evaluate efficacy of these phytoconstituents included Gelatin Zymography, Western Blotting, and real time polymerase chain reaction (RT-PCR) analysis. Moreover, current limitations, challenges, and future directions of using such compounds have been critically discussed. This review underscores the potential implications of phytochemicals in the management of breast cancer which could lessen the growing encumbrance of disease.

The food plant Silybum marianum (L.) Gaertn.: Phytochemistry, Ethnopharmacology and clinical evidence

ETHNOPHARMACOLOGICAL RELEVANCE

Silybum marianum (L.) Gaertn. or Milk thistle is a medicinal plant native to Northern Africa, Southern Europe, Southern Russia and Anatolia. It also grows in South Australia, North and South America. In traditional knowledge, people have used S. marianum for liver disorders such as hepatitis, liver cirrhosis and gallbladder diseases. The main active compound of the plant seeds is silymarin, which is the most commonly used herbal supplement in the United States for liver problems. Nowadays, S. marianum products are available as capsules, powders, and extracts.

AIM OF STUDY

The aim of our study is to draw a more comprehensive overview of the traditional heritage, pharmacological benefits and chemical fingerprint of S. marianum extracts and metabolites; as well as their metabolism and bioavailability.

MATERIALS AND METHODS

An extensive literature search has been conducted using relavant keywords and papers with rationale methodology and robust data were selected and discussed. Studies involving S. marianum or its main active ingredients with regards to hepatoprotective, antidiabetic, cardiovascular protection, anticancer and antimicrobial activities as well as the clinical trials performed on the plant, were discussed here.

RESULTS

S. marianum was subjected to thousands of ethnopharmacological, experimental and clinical investigations. Although, the plant is available for use as a dietary supplement, the FDA did not yet approve its use for cancer therapy. Nowadays, clinical investigations are in progress where a global evidence of its real efficiency is needed.

CONCLUSION

S. marianum is a worldwide used herb with unlimited number of investigations focusing on its benefits and properties, however, little is known about its clinical efficiency. Moreover, few studies have discussed its metabolism, pharmacokinetics and bioavailability, so that all future studies on S. marianum should focus on such areas.

Health Benefits of Silybum marianum: Phytochemistry, Pharmacology, and Applications

Silybum marianum (SM), a well-known plant used as both a medicine and a food, has been widely used to treat various diseases, especially hepatic diseases. The seeds and fruits of SM contain a flavonolignan complex called silymarin, the active compounds of which include silybin, isosilybin, silychristin, dihydrosilybin, silydianin, and so on. In this review, we thoroughly summarize high-quality publications related to the pharmacological effects and underlying mechanisms of SM. SM has antimicrobial, anticancer, hepatoprotective, cardiovascular-protective, neuroprotective, skin-protective, antidiabetic, and other effects. Importantly, SM also counteracts the toxicities of antibiotics, metals, and pesticides. The diverse pharmacological activities of SM provide scientific evidence supporting its use in both humans and animals. Multiple signaling pathways associated with oxidative stress and inflammation are the common molecular targets of SM. Moreover, the flavonolignans of SM are potential agonists of PPARγ and ABCA1, PTP1B inhibitors, and metal chelators. At the end of the review, the potential and perspectives of SM are discussed, and these insights are expected to facilitate the application of SM and the discovery and development of new drugs. We conclude that SM is an interesting dietary medicine for health enhancement and drug discovery and warrants further investigation.

Inhibition of TPA‑induced metastatic potential by morin hydrate in MCF‑7 human breast cancer cells via the Akt/GSK‑3β/c‑Fos signaling pathway

Plant flavonoid 2',3,4',5,7‑pentahydroxyflavone (morin hydrate), isolated from the family Moraceae (Morus alba L.), is known to have anti‑inflammatory and anticancer effects. However, its pharmaceutical effects on metastasis have not been fully elucidated to date. Therefore, the current study investigated the effects of morin hydrate on cancer metastasis in MCF‑7 human breast cancer cells. The results showed that morin hydrate suppressed 12‑O‑tetradecanoylphorbol‑13‑acetate (TPA)‑induced cell migration and invasion via the inhibition of matrix metalloproteinase (MMP)‑9 activity. Furthermore, gene expression level of MMP‑9, MMP‑7, urokinase plasminogen activator (uPA), uPA receptor (uPAR) and fibronectin were significantly decreased by morin hydrate treatment. Morin hydrate inhibited the phosphorylation of Akt and glycogen synthase kinase (GSK)‑3β, and downregulated the expression of an activator protein‑1 subunit c‑Fos. In addition, the GSK‑3β phosphorylation and c‑Fos expression were suppressed by PI3K/Akt pathway inhibitors, LY294002 and wortmannin. Taken together, these results demonstrated that morin hydrate reduced the metastatic potential in TPA‑treated MCF‑7 human breast cancer cells via the inhibition of MMPs, uPA and uPAR, and the underlying Akt/GSK‑3β/c‑Fos pathway. Therefore, the present investigation suggested that morin hydrate may be a natural substance with a preventive potential for metastasis in breast cancer cells.

Phenotypic Screen Identifies JAK2 as a Major Regulator of FAT10 Expression

FAT10 is a ubiquitin-like protein suggested to target proteins for proteasomal degradation. It is highly upregulated upon pro-inflammatory cytokines, namely, TNFα, IFNγ, and IL6, and was found to be highly expressed in various epithelial cancers. Evidence suggests that FAT10 is involved in cancer development and may have a pro-tumorigenic role. However, its biological role is still unclear, as well as its biochemical and cellular regulation. To identify pathways underlying FAT10 expression in the context of pro-inflammatory stimulation, which characterizes the cancerous environment, we implemented a phenotypic transcriptional reporter screen with a library of annotated compounds. We identified AZ960, a potent JAK2 inhibitor, which significantly downregulates FAT10 under pro-inflammatory cytokines induction, in an NFκB-independent manner. We validated JAK2 as a major regulator of FAT10 expression via knockdown, and we suggest that the transcriptional effects are mediated through pSTAT1/3/5. Overall, we have elucidated a pathway regulating FAT10 transcription and discovered a tool compound to chemically downregulate FAT10 expression, and to further study its biology.

Natural dietary antioxidants containing flavonoids modulate keratinocytes physiology: In vitro tri-culture models

ETHNOPHARMACOLOGICAL RELEVANCE

Several traditional medicinal herbs are widely used for dermatologic and cosmetic preparations. The beneficial skin repair activity is detected in various phases of wound-healing process, such as cell-cell, cell-matrix interactions or collagen synthesis.

AIM OF THE STUDY

The study assessed the effects of Opuntia ficus-indica (L.) Mill. (Opuntia) and Milk Thistle (MT) (Silybum marianum (L.) Gaerth) on adult keratinocytes (HaCaT) functioning under basal condition or in the presence of mechanical damage (wounded cells).

MATERIALS AND METHODS

The role of the natural compounds was tested on HaCaT grown in mono-culture and tri-culture configurations. In tri-cultures models, HaCaT were treated with the conditioned media (CM) obtained by Human Normal Dermal Fibroblast (NHDF) and Human Dermal Microvascular Endothelial cells (HMVEC) co-cultures. Specifically, were tested cell viability, oxidative stress mechanisms (cytokines release and lipid peroxidation) and cellular remodelling (growth factors release or metalloproteinase modulation). Moreover, the migratory potential of HaCaT was analysed by the use of wound healing in vitro assay.

RESULTS

Opuntia and MT differently modified the metabolism (EGF, MMP-9), and the migratory properties of HaCaT both under physiological conditions or upon mechanical damage (wounded cells). Moreover, both compounds modulated HaCaT response to oxidative stress. The response to the natural compounds were modified, and in some cases potentiated, in tri-culture configuration systems.

CONCLUSIONS

The data demonstrated that in vitro tri-culture approach is suitable to characterize the role of natural compounds on the complex communication between dermal-epidermal cellular components and microvascular endothelium. Specifically, Opuntia and MT are good alternatives to synthetic compounds in skin repair promotion.

Cabazitaxel and silibinin co-encapsulated cationic liposomes for CD44 targeted delivery: A new insight into nanomedicine based combinational chemotherapy for prostate cancer

Cancer stem cells (CSCs) are the promising targets for cancer chemotherapy that cannot be eliminated by conventional chemotherapy. In this study cationic liposomes of cabazitaxel (CBX) and silibinin (SIL) were prepared with an aim to kill cancer cells and CSCs for prostate cancer. CBX act as cancer cell inhibitor and SIL as CSC inhibitor. Hyaluronic acid (HA), an endogenous anionic polysaccharide was coated on cationic liposomes for targeting CD44 receptors over expressed on CSCs. Liposomes were prepared by ethanol injection method with particle size below 100 nm and entrapment efficiency of more than 90% at 10% w/w drug loading. Liposomes were characterized by dynamic light scattering, transmission electron microscopy, ¹H nuclear magnetic resonance and scanning electron microscopy-energy dispersive x-ray spectroscopy. Liposomes were evaluated for their anticancer action in androgen independent human prostate cancer cell lines (PC-3 and DU-145). HA coated liposomes showed potential cytotoxicity over other groups with low IC₅₀, significantly inhibited cell migration and induced apoptosis. Synergistic cytotoxic effect was also observed with HA coated liposomes that resulted in colony formation inhibition and G2/M phase arrest. Proficient cytotoxicity against CD44⁺ cells (14.87 ± 0.41% in PC-3 and 33.95 ± 0.68% in DU-145 cells) indicated the efficiency of HA coated liposomes towards CSC targeting. Hence, the outcome of this combinational therapy with CD44 targeting indicates the suitability of HA coated CBX and SIL co-loaded liposomes as a potential approach for eradicating prostate cancer and herein might provide a insight for future studies.

Dietary phytochemicals in breast cancer research: anticancer effects and potential utility for effective chemoprevention

Cancerous tissue transformation developing usually over years or even decades of life is a highly complex process involving strong stressors damaging DNA, chronic inflammation, comprehensive interaction between relevant molecular pathways, and cellular cross-talk within the neighboring tissues. Only the minor part of all cancer cases are caused by inborn predisposition; the absolute majority carry a sporadic character based on modifiable risk factors which play a central role in cancer prevention. Amongst most promising candidates for dietary supplements are bioactive phytochemicals demonstrating strong anticancer effects. Abundant evidence has been collected for beneficial effects of flavonoids, carotenoids, phenolic acids, and organosulfur compounds affecting a number of cancer-related pathways. Phytochemicals may positively affect processes of cell signaling, cell cycle regulation, oxidative stress response, and inflammation. They can modulate non-coding RNAs, upregulate tumor suppressive miRNAs, and downregulate oncogenic miRNAs that synergically inhibits cancer cell growth and cancer stem cell self-renewal. Potential clinical utility of the phytochemicals is discussed providing examples for chemoprevention against and therapy for human breast cancer. Expert recommendations are provided in the context of preventive medicine.

A Catechol-Type Resveratrol Analog Manifests Antiangiogenic Action by Constructing an Efficient Catalytic Redox Cycle with Intracellular Copper Ions and NQO1

SCOPE

As part of our research project to understand why dietary polyphenols with the catechol skeleton tend to exhibit cancer chemopreventive activity, a catechol-type resveratrol analog (3,4-dihydroxy-trans-stilbene [3,4-DHS]) was selected to probe its antiangiogenic effects and mechanisms.

METHODS AND RESULTS

The antiangiogenic effects of 3,4-DHS on angiogenesis-related endothelial cell functions were examined, including migration, invasion, and tube formation, and in vivo angiogenesis on a chick chorioallantoic membrane assay. The potential molecular mechanisms for the suppression of cell migration by 3,4-DHS were analyzed using various specific inhibitors. 3,4-DHS was identified as a potent angiogenesis inhibitor by constructing an efficient catalytic redox cycle with intracellular copper ions and NAD(P)H quinone oxidoreductase I to generate reactive oxygen species and thereby downregulate matrix metalloproteinase-9.

CONCLUSION

This work provides further evidence that dietary catechols manifest antiangiogenic activity by virtue of their copper-dependent prooxidative instead of antioxidative role, and useful information for designing polyphenol-inspired angiogenesis inhibitors.

Silencing of casein kinase 2 inhibits PKC‑induced cell invasion by targeting MMP‑9 in MCF‑7 cells

Casein kinase 2 (CK2) is a serine/threonine protein kinase that has been considered to represent an important factor in mammary tumorigenesis. Increased expression of matrix metalloproteinase‑9 (MMP‑9) via nuclear factor‑κB (NF‑κB) activation has been demonstrated to promote breast cancer cell invasion. In the present study, the involvement of CK2 in protein kinase C (PKC) induced cell invasion in MCF‑7 breast cancer cells was investigated as well as the underlying molecular mechanisms. The mRNA and protein levels of MMP‑9 in MCF‑7 cells were investigated using reverse transcription‑quantitative polymerase chain reaction, western blot analyses and a zymography assay. Cell invasiveness was investigated using a Matrigel invasion assay, and it was revealed that small interfering RNA specific for CK2 suppressed PKC induced cell invasion by regulating MMP‑9 expression via activation of the p38 kinase/c‑Jun N‑terminal kinase/NF‑κB pathway. In addition, it was demonstrated that CK2 inhibitors [apigenin (20 µM), emodin (20 µM) or 2‑dimethylamino‑4,5,6,7‑tetrabromo‑1H‑benzimidazole (2 µM)] suppressed PKC induced cell invasion and MMP‑9 expression. The results of the present study suggested that CK2 is an important factor involved in the induction of MCF‑7 breast cancer cell invasion by PKC. Therefore, CK2 may represent novel candidates for therapy intended to inhibit invasion in breast cancer.

Geraniin inhibits migration and invasion of human osteosarcoma cancer cells through regulation of PI3K/Akt and ERK1/2 signaling pathways

Geraniin, an active compound isolated from Geranium sibiricum, was found to inhibit proliferation and induce apoptosis of tumor cells. However, the antimetastatic effects of geraniin remain elusive. Our study found the potential antitumor mechanisms of geraniin through inhibiting the migration and invasion of human osteosarcoma U2OS cells. The western blot, gelatin zymography, and reversed transcription-PCR analysis showed that geraniin suppressed matrix metalloproteinase-9 (MMP-9) expression in a concentration-dependent manner. Geraniin potently suppressed the phosphorylation of extracellular signal regulating kinase (ERK)1/2, phosphatidylinositide-3-kinase (PI3K), and Akt, but did not affect phosphorylation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase. Furthermore, when transforming growth factor-β1 (TGF-β1) was used as an agonist, geraniin inhibited TGF-β1-mediated cell invasion and upregulation of MMP-9. These results suggested that geraniin inhibited U2OS cell migration and invasion by reducing the expression of MMP-9 through the PI3K/Akt and ERK1/2 signaling pathways.

Apomorphine suppresses TNF-α-induced MMP-9 expression and cell invasion through inhibition of ERK/AP-1 signaling pathway in MCF-7 cells

Recent studies have shown that dopamine plays an important role in several types of cancer by inhibiting cell growth and invasion via dopamine receptors (DRs), such as dopamine receptor D2. However, the roles of DR agonists in cancer cell growth and invasion remain unclear. In our study, we found that apomorphine (APO), one of the most commonly prescribed DR agonists, inhibited TNF-α-induced matrix metalloprotease-9 (MMP-9) expression and cell invasion in MCF-7 human breast carcinoma cells through DR-independent pathways. Further mechanistic studies demonstrated that APO suppresses TNF-α-induced transcription of MMP-9 by inhibiting activator protein-1 (AP-1), a well-described transcription factor. This is achieved via extracellular signal-regulated kinases 1 and 2 (ERK1/2). Our study has demonstrated that APO targets human MMP-9 in a DR-independent fashion in MCF-7 cells, suggesting that APO is a potential anticancer agent that can suppress the metastatic progression of cancer cells.

Oldenlandia diffusa suppresses metastatic potential through inhibiting matrix metalloproteinase-9 and intercellular adhesion molecule-1 expression via p38 and ERK1/2 MAPK pathways and induces apoptosis in human breast cancer MCF-7 cells

ETHNOPHARMACOLOGY RELEVANCE

Oldenlandia diffusa (OD) has long been known as an apoptotic inducer in breast tumors in ethnomedicine.

AIM OF THE STUDY

To scientifically confirm the anti-breast cancer effects of water, methanol (MeOH) and butanol (BuOH) extracts of O. diffusa on cell apoptosis, matrix metalloproteinases (MMPs), intercellular adhesion molecule (ICAM)-1 and intracellular signaling in MCF-7 breast cancer cells.

MATERIALS AND METHODS

MeOH extracts (MOD) and BuOH extracts (BOD) were prepared and examined for their ability to inhibit phorbol myristate acetate (PMA)-induced matrix metalloproteinase (MMP)-9 and intercellular adhesion molecule (ICAM)-1 expressions in MCF-7 human breast cancer cells. Additionally, transwell migration, invasion and transcriptional activity were assessed. Results of immunofluorescence confocal microscopy for translocation of NF-κB and p-ERK and p-p38 were also checked. Finally, apoptotic signals including processed caspase-8, caspase-7, poly ADP-ribose polymerase, Bax and Bcl-2 were examined.

RESULTS

MOD and BOD specifically inhibited PMA-induced MMP-9 expression as well as invasive and migration potential via ICAM-1. The inhibitory activity was also based on the suppressed transcriptional activity in MCF-7 breast cancer cells. Results of immunofluorescence confocal microscopy showed that translocation of NF-κB decreased upon BOD and MOD treatments, with a decreased level of p-ERK and p-p38 phosphorylation. In addition, treatment of MCF-7 cells with MOD and BOD activated apoptosis-linked proteins including enzymatically active forms of processed caspase-8, caspase-7 and poly ADP-ribose polymerase, together with increased expression of mitochondrial apoptotic protein, Bax and decreased expression of Bcl-2.

CONCLUSION

The results indicate that OD as an anti-metastatic agent suppresses the metastatic response by targeting p-ERK, p-38 and NF-κB, thus reducing the invasion capacity of MCF-7 breast cancer cells through inhibition of MMP-9 and ICAM-1 expression and plays an important role in the regulation of breast cancer cell apoptosis.

The apoptotic effects of silibinin on MDA-MB-231 and MCF-7 human breast carcinoma cells

Background:

Silibinin is a bioactive flavonolignan extracted from milk thistle, known as Silybum marianum. Silibinin exerts strong antiproliferative, proapoptotic, and anti-inflammatory effects. Many studies have shown that silibinin inhibits experimentally induced malignancies of the liver, prostate, skin, and colon as well as promotes inhibition of the proliferation of cancer cell lines in vitro. This study aimed to investigate the effects of silibinin on the human breast carcinoma cell lines MDA-MB-231 and MCF-7 in monolayer and spheroid cultures.

Method:

The MDA-MB-231 and MCF-7 cell lines were cultured in both monolayer and spheroid cultures. Cells were treated with silibinin at 24, 48, and 72 h of incubation. The 5-bromo-2′-deoxyuridine labeling index was used to determine the cells of the synthesis phase. Poly-ADP-ribose-polimerase immunohistochemical staining and the terminal deoxynucleotidyl transferase dUTP nick and labeling assay were used to determine the death of cells in both the monolayer and spheroid cultures.

Results:

An half maximal inhibitory concentration dose of silibinin in MDA-MB-231 and MCF-7 cells was 100 µM/mL at 24, 48, and 72 h of incubation. Terminal deoxynucleotidyl transferase dUTP nick and labeling positive cells and active poly-ADP-ribose-polimerase were detected after treatment with silibinin in both the monolayer and spheroid cultures. The dead cell count was higher in the MDA-MB-231 and MCF-7 cell lines with silibinin applied than in the controls.

Conclusions:

Our study demonstrated that silibinin applications enhanced terminal deoxynucleotidyl transferase dUTP nick and labeling positive cells and active poly-ADP-ribose-polimerase in comparison to the control in both the monolayer and spheroid cultures.

Suppression of ERK1/2 and hypoxia pathways by four Phyllanthus species inhibits metastasis of human breast cancer cells

Chemotherapies remain far from ideal due to drug resistance; therefore, novel chemotherapeutic agents with higher effectiveness are crucial. The extracts of four Phyllanthus species, namely Phyllanthus niruri, Phyllanthus urinaria, Phyllanthus watsonii, and Phyllanthus amarus, were shown to induce apoptosis and inhibit metastasis of breast carcinoma cells (MCF-7). The main objective of this study was to determine the pathways utilized by these four Phyllanthus species to exert anti-metastatic activities. A cancer 10-pathway reporter was used to investigate the pathways affected by the four Phyllanthus species. Results indicated that these Phyllanthus species suppressed breast carcinoma metastasis and proliferation by suppressing matrix metalloprotein 2 and 9 expression via inhibition of the extracellular signal-related kinase (ERK) pathway. Additionally, inhibition of hypoxia-inducible factor 1-α in the hypoxia pathway caused reduced vascular endothelial growth factor and inducible nitric oxide synthase expression, resulting in anti-angiogenic effects and eventually anti-metastasis. Two-dimensional gel electrophoresis identified numerous proteins suppressed by these Phyllanthus species, including invasion proteins, anti-apoptotic protein, protein-synthesis proteins, angiogenic and mobility proteins, and various glycolytic enzymes. Our results indicated that ERK and hypoxia pathways are the most likely targets of the four Phyllanthus species for the inhibition of MCF-7 metastasis.

Hydroquinone stimulates cell invasion through activator protein-1-dependent induction of MMP-9 in HepG2 human hepatoma cells

Hydroquinone (HQ) is a well-known environmental carcinogen and exposure of humans to HQ can also occur through plant foods, cosmetics, and tobacco products. Although liver is a major organ metabolizing HQ and susceptible to its toxicity, role of HQ in metastatic progression of human hepatocellular carcinoma (HCC) remains unclear. In this study, we examined the effect of HQ on the invasion of HCC cells and its underlying molecular mechanisms. HQ strongly induced matrix metalloproteinase-9 (MMP-9) expression and secretion in HepG2 human hepatoma cells, which were well correlated with increased cell invasion. Mechanistic studies further demonstrated that HQ induced transcriptional activity of MMP-9 gene by activating activator protein-1 (AP-1), the well-known key element mediating MMP-9 gene expression, via MAP kinase (MAPK) signaling pathways. These results suggest that HQ may promote metastatic progression of HCC, although data on in vivo hydroquinone exposure and risk for HCC are contradictory.

Regulatory effects of ΔFosB on proliferation and apoptosis of MCF-7 breast cancer cells

Matrix metalloproteinase-9 (MMP-9) plays a vital role in tumor angiogenesis, cell migration, and invasiveness because it can degrade almost all basement membrane and extracellular matrix components. MMP-9 has been reported in many cancers including breast cancer, lung cancer, and colon cancer. ΔFosB in mammary epithelial cells has been shown to regulate cell proliferation, differentiation, and death. We found that ΔFosB increased the expression of MMP-9 in MCF-7 breast cancer cells. ΔFosB overexpression in MCF-7 cells increased cellular viability and decreased cell apoptosis. SB-3CT, an inhibitor of MMP-9, promoted apoptosis, inhibited cell proliferation, induced cell cycle arrest, and downregulated the expression of antiapoptotic genes Bcl-2 and Bcl-xl in MCF-7 cells. ΔFosB increased the number of MCF-7 cells in G2/M and S phases, upregulated the expression of Bcl-2 and Bcl-xl, and protected MCF-7 cells from apoptosis induced by MMP-9 inhibition. We also found that ΔFosB overexpression in MCF-7 cells inhibited Ca(2+)-induced apoptosis and promoted cell proliferation. Therefore, ΔFosB may be a potential target in breast cancer cell apoptosis by regulating the expression of MMP-9.

Silibinin affects tumor cell growth because of reduction of stemness properties and induction of apoptosis in 2D and 3D models of MDA-MB-468

Silibinin, with a strong antioxidant activity and a weak cytotoxic property, is considered a candidate for cancer prevention. As there is no information on its effect on breast cancer tumor-initiating cells [cancer stem cells (CSCs)] in a 3D culture model, which more closely mimic natural tissues, we carried out this study to determine whether silibinin can target breast CSCs in MDA-MB-468 cells cultured under 3D and 2D conditions. Silibinin was added to culture medium of MDA-MB-468 at a half maximal inhibitory concentration (IC50) dose in 2D and 3D models. Then, stemness properties were assessed using colony and sphere-formation tests. Flow cytometry and real-time PCR were used to determine the different expression levels of stem cell-related marker at protein and mRNA levels under both culture conditions. Our results showed that silibinin inhibits cell growth in a dose-dependent manner by induction of apoptosis, alteration of the cell cycle, reduction of stemness properties and function, and induction of tumoral differentiation. The mechanism of silibinin action and also the response of tumor cells differed when cells were cultured in a 3D model compared with a 2D model. Silibinin may potentially target breast CSCs. Moreover, tumor-initiating cells are more sensitive to silibinin in a 3D culture than in a 2D culture.

Aurora kinases are essential for PKC-induced invasion and matrix metalloproteinase-9 expression in MCF-7 breast cancer cells

The Aurora kinase family of serine/threonine kinases are known to be crucial for cell cycle control. Aurora kinases are considered a target of anticancer drugs. However, few studies have assessed the effect of Aurora kinases in breast cancer. In the present study, to determine whether Aurora kinases play a role in oncogenic actions of protein kinase C (PKC), we investigated the effect of Aurora kinases on PKC-induced invasion and MMP-9 expression using breast cancer cells. Treatment of MCF-7 cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) induced the upregulation and phosphorylation of Aurora kinases via the MAPK signaling pathway. Moreover, the inhibition of Aurora kinases by their siRNAs and inhibitors suppressed TPA-induced cell invasion and expression of MMP-9 by inhibiting the activation of NF-κB/AP-1, major transcription factors for MMP-9 expression in MCF-7 cells. These results suggested that Aurora kinases mediate PKC-MAPK signal to NF-κB/AP-1 with increasing MMP-9 expression and invasion of MCF-7 cells. To the best of our knowledge, this is the first study to show that Aurora kinases are key molecules in PKC-induced invasion in breast cancer cells.

Inhibitory effects of kaempferol on the invasion of human breast carcinoma cells by downregulating the expression and activity of matrix metalloproteinase-9

Matrix metalloproteinases (MMPs) have been regarded as major critical molecules assisting tumor cells during metastasis, for excessive ECM (ECM) degradation, and cancer cell invasion. In the present study, in vitro and in vivo assays were employed to examine the inhibitory effects of kaempferol, a natural polyphenol of flavonoid family, on tumor metastasis. Data showed that kaempferol could inhibit adhesion, migration, and invasion of MDA-MB-231 human breast carcinoma cells. Moreover, kaempferol led to the reduced activity and expression of MMP-2 and MMP-9, which were detected by gelatin zymography, real-time PCR, and western blot analysis, respectively. Further elucidation of the mechanism revealed that kaempferol treatment inhibited the activation of transcription factor activator protein-1 (AP-1) and MAPK signaling pathway. Moreover, kaempferol repressed phorbol-12-myristate-13-acetate (PMA)-induced MMP-9 expression and activity through suppressing the translocation of protein kinase Cδ (PKCδ) and MAPK signaling pathway. Our results also indicated that kaempferol could block the lung metastasis of B16F10 murine melanoma cells as well as the expression of MMP-9 in vivo. Taken together, these results demonstrated that kaempferol could inhibit cancer cell invasion through blocking the PKCδ/MAPK/AP-1 cascade and subsequent MMP-9 expression and its activity. Therefore, kaempferol might act as a therapeutic potential candidate for cancer metastasis.

Silibinin, a novel chemokine receptor type 4 antagonist, inhibits chemokine ligand 12-induced migration in breast cancer cells

PURPOSE

C-X-C chemokine receptor type 4 (CXCR4) signaling has been demonstrated to be involved in cancer invasion and migration; therefore, CXCR4 antagonist can serve as an anti-cancer drug by preventing tumor metastasis. This study aimed to identify the CXCR4 antagonists that could reduce and/or inhibit tumor metastasis from natural products.

METHODS AND RESULTS

According to the molecular docking screening, we reported here silibinin as a novel CXCR4 antagonist. Biochemical characterization showed that silibinin blocked chemokine ligand 12 (CXCL12)-induced CXCR4 internalization by competitive binding to CXCR4, therefore inhibiting downstream intracellular signaling. In human breast cancer cells MDA-MB-231, which expresses high levels of CXCR4, inhibition of CXCL12-induced chemomigration can be found under silibinin treatment. Overexpression of CXCL12 sensitized MDA-MB-231 cells to the inhibition of silibinin, which was abolished by CXCR4 knockdown. The inhibition of silibinin was also observed in MCF-7/CXCR4 cells rather than MCF-7 cells that express low level of CXCR4.

CONCLUSIONS

Our work demonstrated that silibinin is a novel CXCR4 antagonist that may have potential therapeutic use for prevention of tumor metastasis.

Flavonoids from each of the six structural groups reactivate BRM, a possible cofactor for the anticancer effects of flavonoids

Flavonoids have been extensively studied and are well documented to have anticancer effects, but it is not entirely known how they impact cellular mechanisms to elicit these effects. In the course of this study, we found that a variety of different flavonoids readily restored Brahma (BRM) in BRM-deficient cancer cell lines. Flavonoids from each of the six different structural groups were effective at inducing BRM expression as well as inhibiting growth in these BRM-deficient cancer cells. By blocking the induction of BRM with shRNA, we found that flavonoid-induced growth inhibition was BRM dependent. We also found that flavonoids can restore BRM functionality by reversing BRM acetylation. In addition, we observed that an array of natural flavonoid-containing products both induced BRM expression as well as deacetylated the BRM protein. We also tested two of the BRM-inducing flavonoids (Rutin and Diosmin) at both a low and a high dose on the development of tumors in an established murine lung cancer model. We found that these flavonoids effectively blocked development of adenomas in the lungs of wild-type mice but not in that of BRMnull mice. These data demonstrate that BRM expression and function are regulated by flavonoids and that functional BRM appears to be a prerequisite for the anticancer effects of flavonoids both in vitro and in vivo.

Targeting tumor microenvironment with silibinin: promise and potential for a translational cancer chemopreventive strategy

Tumor microenvironment (TME) refers to the dynamic cellular and extra-cellular components surrounding tumor cells at each stage of the carcinogenesis. TME has now emerged as an integral and inseparable part of the carcinogenesis that plays a critical role in tumor growth, angiogenesis, epithelial to mesenchymal transition (EMT), invasion, migration and metastasis. Besides its vital role in carcinogenesis, TME is also a better drug target because of its relative genetic stability with lesser probability for the development of drug-resistance. Several drugs targeting the TME (endothelial cells, macrophages, cancer-associated fibroblasts, or extra-cellular matrix) have either been approved or are in clinical trials. Recently, non-steroidal anti-inflammatory drugs targeting inflammation were reported to also prevent several cancers. These exciting developments suggest that cancer chemopreventive strategies targeting both tumor and TME would be better and effective towards preventing, retarding or reversing the process of carcinogenesis. Here, we have reviewed the effect of a well established hepatoprotective and chemopreventive agent silibinin on cellular (endothelial, fibroblast and immune cells) and non-cellular components (cytokines, growth factors, proteinases etc.) of the TME. Silibinin targets TME constituents as well as their interaction with cancer cells, thereby inhibiting tumor growth, angiogenesis, inflammation, EMT, and metastasis. Silibinin is already in clinical trials, and based upon completed studies we suggest that its chemopreventive effectiveness should be verified through its effect on biological end points in both tumor and TME. Overall, we believe that the chemopreventive strategies targeting both tumor and TME have practical and translational utility in lowering the cancer burden.

New Therapeutic Potentials of Milk Thistle (Silybum marianum)

Silymarin is a bioflavonoid complex extract derived from dry seeds of Milk thistle [( Silybum marianum(L.) Gaernt. (Fam. Asteraceae/Compositaceae)] whose hepatoprotective effect has clinically been proved. Low toxicity, favorable pharmacokinetics, powerful antioxidant, detoxifying, preventive, protective and regenerative effects and side effects similar to placebo make silymarin extremely attractive and safe for therapeutic use. The medicinal properties of silymarin and its main component silibinin have been studied in the treatment of Alzheimer's disease, Parkinson's disease, sepsis, burns, osteoporosis, diabetes, cholestasis and hypercholesterolemia. Owing to its apoptotic effect, without cytotoxic effects, silymarin possesses potential applications in the treatment of various cancers. Silymarin is being examined as a neuro-, nephro- and cardio-protective in the damage of different etiologies due to its strong antioxidant potentials. Furthermore, it has fetoprotective (against the influence of alcohol) and prolactin effects and is safe to be used during pregnancy and lactation. Finally, the cosmetics industry is examining the antioxidant and UV-protective effects of silymarin. Further clinical studies and scientific evidence that silymarin and silibinin are effective in the therapy of various pathologies are indispensable in order to confirm their different flavonolignan pharmacological effects.

Adenosine dialdehyde suppresses MMP-9-mediated invasion of cancer cells by blocking the Ras/Raf-1/ERK/AP-1 signaling pathway

Adenosine dialdehyde (AdOx) inhibits transmethylation by the accumulation of S-adenosylhomocysteine (SAH), a negative feedback inhibitor of methylation, through the suppression of SAH hydrolase (SAHH). In this study, we aimed to determine the regulatory effect of AdOx on cancer invasion by using three different cell lines: MDA-MB-231, MCF-7, and U87. The invasive capacity of these cells in the presence (MCF-7) or absence (MDA-MB-231 and U87) of phorbal 12-myristate 13-acetate (PMA) was strongly decreased by AdOx treatment. Furthermore, the expression, secretion, and activation of matrix metalloproteinase (MMP)-9, a critical enzyme regulating cell invasion, in these cells were diminished by AdOx treatment. AdOx strongly suppressed AP-1-mediated luciferase activity and, in parallel, reduced the translocation of c-Fos and c-Jun into the nucleus. AdOx was shown to block a series of upstream AP-1 activation signaling complexes composed of extracellular signal-related kinase (ERK), mitogen-activated protein ERK kinase (MEK)1/2, Raf-1, and Ras, as assessed by measuring the levels of the phosphorylated and membrane-translocated forms. Furthermore, we found that suppression of SAHH by siRNA and 3-deazaadenosine, knock down of isoprenylcysteine carboxyl methyltransferase (ICMT), and treatment with SAH showed inhibitory patterns similar to those of AdOx. Therefore, our data suggest that AdOx is capable of targeting the methylation reaction regulated by SAHH and ICMT and subsequently downregulating MMP-9 expression and decreasing invasion of cancer cells through inhibition of the Ras/Raf-1/ERK/AP-1 pathway.

Resveratrol induces MMP-9 and cell migration via the p38 kinase and PI-3K pathways in HT1080 human fibrosarcoma cells

Trans-3,4',5-trihydroxystilbene (resveratrol) is a grape polyphenol present in various plants, food products, red wine and grapes. Resveratrol has anti-inflammatory, anticarcinogenic, anti-oxidant and anti-aging properties. Matrix metalloproteinases (MMPs) are key enzymes involved in the degradation of the extracellular matrix, and their expression may be regulated in cancer metastasis. In the present study, we aimed to evaluate the effect of resveratrol on MMPs and cell migration, and to understand the mechanism of action in HT1080 human fibrosarcoma cells. We found that resveratrol inhibited HT1080 cell viability at various concentrations as detected by the MTT assay and FACS analysis. However, resveratrol dramatically increased the activation and expression of MMP-9 in a dose- and time-dependent manner, as determined by gelatin zymography assay and western blot analysis. We also discovered that resveratrol enhanced the migratory ability of HT1080 cells, as determined by the wound healing assay, and decreased the phosphorylation of p38 kinase. Moreover, the Akt kinase was inhibited by resveratrol in the HT1080 cells. The inhibition of p38 and Akt kinases with SB203580 and LY294002 further increased resveratrol-induced MMP-9 as well as cell migration in the HT1080 cells. Our results suggest that resveratrol regulates MMP-9 and migratory abilities through the p38 kinase and PI-3K pathways in HT1080 human fibrosarcoma cells.

Curcumin suppresses the TPA-induced invasion through inhibition of PKCα-dependent MMP-expression in MCF-7 human breast cancer cells

Curcumin (diferuloylmethane) is a polyphenol derived from the plant turmeric (Curcuma longa), which is commonly used as a spice. Although anti-carcinogenic, anti-oxidant, anti-inflammation, and anti-angiogenic properties have been reported, the effect of curcumin on breast cancer metastasis is unknown. Matrix metalloproteinase-9 (MMP-9) is a major component in cancer cell invasion. In this study, we investigated the inhibitory effect of curcumin on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced MMP-9 expression and cell invasion and the molecular mechanisms involved in MCF-7 cells. Our results showed that curcumin inhibits TPA-induced MMP-9 expression and cell invasion through suppressing NF-κB and AP-1 activation. Also, curcumin strongly repressed the TPA-induced phosphorylation of p38 and JNK and inhibited TPA-induced translocation of PKCα from the cytosol to the membrane, but did not affect the translocation of PKCδ. These results indicate that curcumin-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involves the suppression of the PKCα, MAPK and NF-κB/AP-1 pathway in MCF-7 cells. Curcumin may have potential value in restricting breast cancer metastasis.

VI-14, a novel flavonoid derivative, inhibits migration and invasion of human breast cancer cells

It has been well characterized that flavonoids possess pronounced anticancer potentials including anti-angiogenesis, anti-metastasis, and pro-apoptosis. Herein, we report, for the first time, that VI-14, a novel flavonoid derivative, possesses anti-cancer properties. The purpose of this study is to investigate the anti-migration and anti-invasion activities of VI-14 in breast cancer cells. Our data indicate that VI-14 inhibits adhesion, migration and invasion of MDA-MB-231 and MDA-MB-435 human breast cancer cells. MDA-MB-231 cells treated with VI-14 display reduced activities and expressions of ECM degradation-associated proteins including matrix metalloproteinase 2 (MMP-2) and 9 (MMP-9) at both the protein and mRNA levels. Meanwhile, VI-14 treatment induces an up-regulated expression of tissue inhibitor of metalloproteinase 1 (TIMP-1) and 2 (TIMP-2) in MDA-MB-231 cells. Western blotting results show that phosphorylation levels of critical components of the MAPK signaling pathway, including ERK, JNK and P38, are dramatically decreased in VI-14-treated MDA-MB-231 cells. Furthermore, treatment of VI-14 significantly decreases the nuclear levels and the binding ability of nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1). Taken together, our data suggest that VI-14 treatment suppresses migration and motility of breast cancer cells, and VI-14 may be a potential compound for cancer therapy.

Modulation of angiogenesis by dietary phytoconstituents in the prevention and intervention of breast cancer

Breast cancer is the leading cause of cancer-related deaths for women in the United States and the rest of the world. About 8% of women develop breast cancer during the course of their lives. Dietary habits are closely associated with both the risk and progression of breast cancer. Dietary agents have accumulated increasing importance with regards to the prevention and treatment of breast cancer. One such manner by which these compounds can target breast cancer development and progression is through interference with the angiogenic pathways. Angiogenesis is an intricate process that involves the development of new capillaries from previously existing blood vessels. Disruption of this pathway, therefore, provides a novel and effective avenue for therapeutic intervention of breast cancer. Various phytochemicals found in the diet kill breast cancer cells in vitro and prevent as well as suppress breast cancer progression in various preclinical animal models. This review examines the value of dietary phytoconstituents in the prevention and treatment of breast cancer through modulation of the intricate and complex process of angiogenesis. In addition, the potential benefits, challenges, and future directions of research on anti-angiogenic dietary phytochemicals in the prevention and intervention of breast cancer are also addressed.