Role of Silymarin in Cancer Treatment: Facts, Hypotheses, and Questions

The flavonoid silymarin extracted from the seeds of Sylibum marianum is a mixture of 6 flavolignan isomers. The 3 more important isomers are silybin (or silibinin), silydianin, and silychristin. Silybin is functionally the most active of these compounds. This group of flavonoids has been extensively studied and they have been used as hepato-protective substances for the mushroom Amanita phalloides intoxication and mainly chronic liver diseases such as alcoholic cirrhosis and nonalcoholic fatty liver. Hepatitis C progression is not, or slightly, modified by silymarin. Recently, it has also been proposed for SARS COVID-19 infection therapy. The biochemical and molecular mechanisms of action of these substances in cancer are subjects of ongoing research. Paradoxically, many of its identified actions such as antioxidant, promoter of ribosomal synthesis, and mitochondrial membrane stabilization, may seem protumoral at first sight, however, silymarin compounds have clear anticancer effects. Some of them are: decreasing migration through multiple targeting, decreasing hypoxia inducible factor-1α expression, inducing apoptosis in some malignant cells, and inhibiting promitotic signaling among others. Interestingly, the antitumoral activity of silymarin compounds is limited to malignant cells while the nonmalignant cells seem not to be affected. Furthermore, there is a long history of silymarin use in human diseases without toxicity after prolonged administration. The ample distribution and easy accessibility to milk thistle—the source of silymarin compounds, its over the counter availability, the fact that it is a weed, some controversial issues regarding bioavailability, and being a nutraceutical rather than a drug, has somehow led medical professionals to view its anticancer effects with skepticism. This is a fundamental reason why it never achieved bedside status in cancer treatment. However, in spite of all the antitumoral effects, silymarin actually has dual effects and in some cases such as pancreatic cancer it can promote stemness. This review deals with recent investigations to elucidate the molecular actions of this flavonoid in cancer, and to consider the possibility of repurposing it. Particular attention is dedicated to silymarin's dual role in cancer and to some controversies of its real effectiveness.

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The Application of Citrus folium in Breast Cancer and the Mechanism of Its Main Component Nobiletin: A Systematic Review

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2021/2847466 ◽

2021 ◽

Vol 2021 ◽

pp. 1-15

Author(s):

Yuan Wu ◽

Chien-shan Cheng ◽

Qiong Li ◽

Jing-xian Chen ◽

Ling-ling Lv ◽

...

Keyword(s):

Breast Cancer ◽

Chinese Medicine ◽

Cancer Treatment ◽

Structural Changes ◽

Molecular Mechanisms ◽

Drug Candidate ◽

Antitumor Effects ◽

Chemotherapy Drugs ◽

Anticancer Effects

Citrus folium and its main ingredient nobiletin (NOB) have received widespread attention in recent years due to their antitumor effects. The antitumor effect of Citrus folium is related to the traditional use, mainly in its Chinese medicinal properties of soothing the liver and promoting qi, resolving phlegm, and dispelling stagnation. Some studies have proved that Citrus folium and NOB are more effective for triple-negative breast cancer (TNBC), which is related to the syndrome of stagnation of liver qi. From the perspective of modern biomedical research, NOB has anticancer effects. Its potential molecular mechanisms include inhibition of the cell cycle, induction of apoptosis, and inhibition of angiogenesis, invasion, and migration. Citrus folium and NOB can also reduce the side effects of chemotherapy drugs and reverse multidrug resistance (MDR). However, more research studies are needed to clarify the underlying mechanisms. The modern evidence of Citrus folium and NOB in breast cancer treatment has a strong connection with the traditional concepts and laws of applying Citrus folium in Chinese medicine (CM). As a low-toxic anticancer drug candidate, NOB and its structural changes, Citrus folium, and compound prescriptions will attract scientists to use advanced technologies such as genomics, proteomics, and metabolomics to study its potential anticancer effects and mechanisms. On the contrary, there are relatively few studies on the anticancer effects of Citrus folium and NOB in vivo. The clinical application of Citrus folium and NOB as new cancer treatment drugs requires in vivo verification and further anticancer mechanism research. This review aims to provide reference for the treatment of breast cancer by Chinese medicine.

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Role of hyperoxic treatment in cancer

Experimental Biology and Medicine ◽

10.1177/1535370220921547 ◽

2020 ◽

Vol 245 (10) ◽

pp. 851-860

Author(s):

Sei W Kim ◽

In K Kim ◽

Sang H Lee

Keyword(s):

Cancer Treatment ◽

Cancer Progression ◽

Molecular Mechanisms ◽

Cell Function ◽

Immune Cell ◽

Current Knowledge ◽

Hypoxia Inducible Factor ◽

Tumor Hypoxia ◽

Multiple Tumor ◽

Hypoxic State

The occurrence of hypoxia is common in many solid tumors, and it enhances aggressive features of cancer such as cell survival, angiogenesis, and metastasis while minimizing the efficacies of chemotherapy and radiotherapy. Hypoxia also plays a pivotal role in regulating immune cell function which is important for immunotherapy. Hypoxia-inducible factor has been suggested as a master regulator of tumor cell adaptation to the hypoxic microenvironment. Currently, several approaches have been proposed to eliminate the hypoxic state in tumors for delaying cancer progression and improving therapeutic efficacy. In this review, we summarize current findings on the relevance of hyperoxia-based therapeutics for cancer treatment. Accumulating evidence indicates that hyperoxic therapy inhibits tumor growth and increases treatment efficacy. Primary antitumor effect of hyperoxic therapy may be due to the reversal of tumor hypoxia and the generation of reactive oxygen species. Restoring immune function is also suggested as a potential mechanism. Hyperoxic therapy can also cause cellular injury and organ dysfunction. In conclusion, overcoming tumor hypoxia is a major problem that needs to be solved. Further studies to standardize and personalize hyperoxia therapy according to the type of cancer, stage, and comorbidities are needed. Impact statement Tumor hypoxia promotes cancer cell aggressiveness, and is strongly associated with poor prognosis across multiple tumor types. The hypoxic microenvironments inside tumors also limit the effectiveness of radiotherapy, chemotherapy, and immunotherapy. Several approaches to eliminate hypoxic state in tumors have been proposed to delay cancer progression and improve therapeutic efficacies. This review will summarize current knowledge on hyperoxia, used alone or in combination with other therapeutic modalities, in cancer treatment. Molecular mechanisms and undesired side effects of hyperoxia will also be discussed.

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NOB1: A Potential Biomarker or Target in Cancer

Current Drug Targets ◽

10.2174/1389450120666190308145346 ◽

2019 ◽

Vol 20 (10) ◽

pp. 1081-1089

Author(s):

Weiwei Ke ◽

Zaiming Lu ◽

Xiangxuan Zhao

Keyword(s):

Cancer Treatment ◽

Molecular Mechanisms ◽

Rna Binding ◽

Binding Protein ◽

Tumor Development ◽

Anticancer Therapy ◽

Research Progress ◽

Normal Tissues ◽

Potential Biomarker

Human NIN1/RPN12 binding protein 1 homolog (NOB1), an RNA binding protein, is expressed ubiquitously in normal tissues such as the lung, liver, and spleen. Its core physiological function is to regulate protease activities and participate in maintaining RNA metabolism and stability. NOB1 is overexpressed in a variety of cancers, including pancreatic cancer, non-small cell lung cancer, ovarian cancer, prostate carcinoma, osteosarcoma, papillary thyroid carcinoma, colorectal cancer, and glioma. Although existing data indicate that NOB1 overexpression is associated with cancer growth, invasion, and poor prognosis, the molecular mechanisms behind these effects and its exact roles remain unclear. Several studies have confirmed that NOB1 is clinically relevant in different cancers, and further research at the molecular level will help evaluate the role of NOB1 in tumors. NOB1 has become an attractive target in anticancer therapy because it is overexpressed in many cancers and mediates different stages of tumor development. Elucidating the role of NOB1 in different signaling pathways as a potential cancer treatment will provide new ideas for existing cancer treatment methods. This review summarizes the research progress made into NOB1 in cancer in the past decade; this information provides valuable clues and theoretical guidance for future anticancer therapy by targeting NOB1.

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Hypoxia, Metabolic Reprogramming, and Drug Resistance in Liver Cancer

Cells ◽

10.3390/cells10071715 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1715

Author(s):

Macus Hao-Ran Bao ◽

Carmen Chak-Lui Wong

Keyword(s):

Hepatocellular Carcinoma ◽

Drug Resistance ◽

Liver Cancer ◽

Effective Treatment ◽

Molecular Mechanisms ◽

Hypoxia Inducible Factor ◽

Metabolic Reprogramming ◽

Combination Therapies ◽

Low Oxygen ◽

Treatment Regimens

Hypoxia, low oxygen (O2) level, is a hallmark of solid cancers, especially hepatocellular carcinoma (HCC), one of the most common and fatal cancers worldwide. Hypoxia contributes to drug resistance in cancer through various molecular mechanisms. In this review, we particularly focus on the roles of hypoxia-inducible factor (HIF)-mediated metabolic reprogramming in drug resistance in HCC. Combination therapies targeting hypoxia-induced metabolic enzymes to overcome drug resistance will also be summarized. Acquisition of drug resistance is the major cause of unsatisfactory clinical outcomes of existing HCC treatments. Extra efforts to identify novel mechanisms to combat refractory hypoxic HCC are warranted for the development of more effective treatment regimens for HCC patients.

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Let-7f miRNA regulates SDF-1α- and hypoxia-promoted migration of mesenchymal stem cells and attenuates mammary tumor growth upon exosomal release

Cell Death and Disease ◽

10.1038/s41419-021-03789-3 ◽

2021 ◽

Vol 12 (6) ◽

Author(s):

Virginia Egea ◽

Kai Kessenbrock ◽

Devon Lawson ◽

Alexander Bartelt ◽

Christian Weber ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Tumor Growth ◽

Molecular Mechanisms ◽

Hypoxia Inducible Factor ◽

Human Mesenchymal Stem Cells ◽

Target Cells ◽

Autophagic Flux ◽

Stromal Cell Derived Factor

AbstractBone marrow-derived human mesenchymal stem cells (hMSCs) are recruited to damaged or inflamed tissues where they contribute to tissue repair. This multi-step process involves chemokine-directed invasion of hMSCs and on-site release of factors that influence target cells or tumor tissues. However, the underlying molecular mechanisms are largely unclear. Previously, we described that microRNA let-7f controls hMSC differentiation. Here, we investigated the role of let-7f in chemotactic invasion and paracrine anti-tumor effects. Incubation with stromal cell-derived factor-1α (SDF-1α) or inflammatory cytokines upregulated let-7f expression in hMSCs. Transfection of hMSCs with let-7f mimics enhanced CXCR4-dependent invasion by augmentation of pericellular proteolysis and release of matrix metalloproteinase-9. Hypoxia-induced stabilization of the hypoxia-inducible factor 1 alpha in hMSCs promoted cell invasion via let-7f and activation of autophagy. Dependent on its endogenous level, let-7f facilitated hMSC motility and invasion through regulation of the autophagic flux in these cells. In addition, secreted let-7f encapsulated in exosomes was increased upon upregulation of endogenous let-7f by treatment of the cells with SDF-1α, hypoxia, or induction of autophagy. In recipient 4T1 tumor cells, hMSC-derived exosomal let-7f attenuated proliferation and invasion. Moreover, implantation of 3D spheroids composed of hMSCs and 4T1 cells into a breast cancer mouse model demonstrated that hMSCs overexpressing let-7f inhibited tumor growth in vivo. Our findings provide evidence that let-7f is pivotal in the regulation of hMSC invasion in response to inflammation and hypoxia, suggesting that exosomal let-7f exhibits paracrine anti-tumor effects.

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Network pharmacology and molecular docking study on the active ingredients of qidengmingmu capsule for the treatment of diabetic retinopathy

Scientific Reports ◽

10.1038/s41598-021-86914-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mingxu Zhang ◽

Jiawei Yang ◽

Xiulan Zhao ◽

Ying Zhao ◽

Siquan Zhu

Keyword(s):

Diabetic Retinopathy ◽

Molecular Docking ◽

Molecular Mechanisms ◽

Hypoxia Inducible Factor ◽

Enrichment Analysis ◽

Docking Study ◽

Network Pharmacology ◽

Biological Processes ◽

Active Ingredients ◽

Molecular Docking Study

AbstractDiabetic retinopathy (DR) is a leading cause of irreversible blindness globally. Qidengmingmu Capsule (QC) is a Chinese patent medicine used to treat DR, but the molecular mechanism of the treatment remains unknown. In this study, we identified and validated potential molecular mechanisms involved in the treatment of DR with QC via network pharmacology and molecular docking methods. The results of Ingredient-DR Target Network showed that 134 common targets and 20 active ingredients of QC were involved. According to the results of enrichment analysis, 2307 biological processes and 40 pathways were related to the treatment effects. Most of these processes and pathways were important for cell survival and were associated with many key factors in DR, such as vascular endothelial growth factor-A (VEGFA), hypoxia-inducible factor-1A (HIF-1Α), and tumor necrosis factor-α (TNFα). Based on the results of the PPI network and KEGG enrichment analyses, we selected AKT1, HIF-1α, VEGFA, TNFα and their corresponding active ingredients for molecular docking. According to the molecular docking results, several key targets of DR (including AKT1, HIF-1α, VEGFA, and TNFα) can form stable bonds with the corresponding active ingredients of QC. In conclusion, through network pharmacology methods, we found that potential biological mechanisms involved in the alleviation of DR by QC are related to multiple biological processes and signaling pathways. The molecular docking results also provide us with sound directions for further experiments.

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Pharmacological and Antioxidant Activities of Rhus coriaria L. (Sumac)

Antioxidants ◽

10.3390/antiox10010073 ◽

2021 ◽

Vol 10 (1) ◽

pp. 73

Author(s):

Halima Alsamri ◽

Khawlah Athamneh ◽

Gianfranco Pintus ◽

Ali H. Eid ◽

Rabah Iratni

Keyword(s):

Cardiovascular Disease ◽

Mediterranean Region ◽

Molecular Mechanisms ◽

Antioxidant Activities ◽

Polyphenolic Compounds ◽

Therapeutic Benefits ◽

Anticancer Effects ◽

Antioxidant Capacities ◽

Rhus Coriaria ◽

Flavoring Agent

Rhus coriaria L. (Anacardiaceae), commonly known as sumac, is a commonly used spice, condiment, and flavoring agent, especially in the Mediterranean region. Owing to its bountiful beneficial values, sumac has been used in traditional medicine for the management and treatment of many ailments including hemorrhoids, wound healing, diarrhea, ulcer, and eye inflammation. This plant is rich in various classes of phytochemicals including flavonoids, tannins, polyphenolic compounds, organic acids, and many others. By virtue of its bioactive, Rhus coriaria possesses powerful antioxidant capacities that have ameliorative and therapeutic benefits for many common diseases including cardiovascular disease, diabetes, and cancer. This review describes the phytochemical properties of R. coriaria and then focuses on the potent antioxidant capacities of sumac. We then dissect the cellular and molecular mechanisms of sumac’s action in modulating many pathophysiological instigators. We show how accumulating evidence supports the antibacterial, antinociceptive, antidiabetic, cardioprotective, neuroprotective, and anticancer effects of this plant, especially that toxicity studies show that sumac is very safe to consume by humans and has little toxicity. Taken together, the findings we summarize here support the utilization of this plant as an attractive target for drug discovery.

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Hypoxic tumor microenvironment: Implications for cancer therapy

Experimental Biology and Medicine ◽

10.1177/1535370220934038 ◽

2020 ◽

Vol 245 (13) ◽

pp. 1073-1086

Author(s):

Sukanya Roy ◽

Subhashree Kumaravel ◽

Ankith Sharma ◽

Camille L Duran ◽

Kayla J Bayless ◽

...

Keyword(s):

Tumor Microenvironment ◽

Cancer Cells ◽

Metabolic Regulation ◽

Molecular Mechanisms ◽

Hypoxia Inducible Factor ◽

Tumor Vasculature ◽

Therapeutic Strategies ◽

Therapeutic Resistance ◽

Low Oxygen ◽

Cancer Types

Hypoxia or low oxygen concentration in tumor microenvironment has widespread effects ranging from altered angiogenesis and lymphangiogenesis, tumor metabolism, growth, and therapeutic resistance in different cancer types. A large number of these effects are mediated by the transcription factor hypoxia inducible factor 1⍺ (HIF-1⍺) which is activated by hypoxia. HIF1⍺ induces glycolytic genes and reduces mitochondrial respiration rate in hypoxic tumoral regions through modulation of various cells in tumor microenvironment like cancer-associated fibroblasts. Immune evasion driven by HIF-1⍺ further contributes to enhanced survival of cancer cells. By altering drug target expression, metabolic regulation, and oxygen consumption, hypoxia leads to enhanced growth and survival of cancer cells. Tumor cells in hypoxic conditions thus attain aggressive phenotypes and become resistant to chemo- and radio- therapies resulting in higher mortality. While a number of new therapeutic strategies have succeeded in targeting hypoxia, a significant improvement of these needs a more detailed understanding of the various effects and molecular mechanisms regulated by hypoxia and its effects on modulation of the tumor vasculature. This review focuses on the chief hypoxia-driven molecular mechanisms and their impact on therapeutic resistance in tumors that drive an aggressive phenotype. Impact statement Hypoxia contributes to tumor aggressiveness and promotes growth of many solid tumors that are often resistant to conventional therapies. In order to achieve successful therapeutic strategies targeting different cancer types, it is necessary to understand the molecular mechanisms and signaling pathways that are induced by hypoxia. Aberrant tumor vasculature and alterations in cellular metabolism and drug resistance due to hypoxia further confound this problem. This review focuses on the implications of hypoxia in an inflammatory TME and its impact on the signaling and metabolic pathways regulating growth and progression of cancer, along with changes in lymphangiogenic and angiogenic mechanisms. Finally, the overarching role of hypoxia in mediating therapeutic resistance in cancers is discussed.

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HIF-1α Inhibition Sensitized Pituitary Adenoma Cells to Temozolomide by Regulating Presenilin 1 Expression and Autophagy

Technology in Cancer Research & Treatment ◽

10.1177/1533034615618834 ◽

2016 ◽

Vol 15 (6) ◽

pp. NP95-NP104 ◽

Cited By ~ 6

Author(s):

Zhang kun ◽

Yang yuling ◽

Wang dongchun ◽

Xie bingbing ◽

Li xiaoli ◽

...

Keyword(s):

Pituitary Adenoma ◽

Pituitary Adenomas ◽

Ph Value ◽

Hypoxia Inducible Factor ◽

Presenilin 1 ◽

Gh3 Cells ◽

Lysosomal Ph ◽

Hypoxia Inducible Factor 1Α ◽

Anticancer Effects ◽

Autophagy Induction

Pituitary adenomas usually develop temozolomide resistance, which could compromise the anticancer effects of temozolomide. Suppression of hypoxia-inducible factor 1α has been shown to sensitize glioblastoma cells to temozolomide treatment according to previous reports. However, whether and how the suppression of hypoxia-inducible factor 1α could sensitize pituitary adenomas to temozolomide treatment are still poorly understood. In the present study, using hypoxia-inducible factor 1α knockdown strategy, we demonstrated for the first time that hypoxia-inducible factor 1α knockdown could inhibit temozolomide-induced autophagy in rat pituitary adenoma GH3 cells and thus increase antitumor efficacy of temozolomide. Furthermore, we found hypoxia-inducible factor 1α knockdown could block autophagy process through neutralizing lysosomal pH value but not inhibiting autophagy induction. Finally, we found hypoxia-inducible factor 1α could regulate lysosomal pH value through regulating full length presenilin 1 expression, and exogenous reexpression of presenilin 1could restore lysosome acidic levels. Our data indicated hypoxia-inducible factor 1α knockdown could be a potential approach to improve the efficacy of temozolomide therapy for pituitary adenomas.

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