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

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.

The Apoptotic and Anti-Warburg Effects of Brassinin in PC-3 Cells via Reactive Oxygen Species Production and the Inhibition of the c-Myc, SIRT1, and β-Catenin Signaling Axis

Though Brassinin is known to have antiangiogenic, anti-inflammatory, and antitumor effects in colon, prostate, breast, lung, and liver cancers, the underlying antitumor mechanism of Brassinin is not fully understood so far. Hence, in the current study, the apoptotic mechanism of Brassinin was explored in prostate cancer. Herein, Brassinin significantly increased the cytotoxicity and reduced the expressions of pro-Poly ADP-ribose polymerase (PARP), pro-caspase 3, and B-cell lymphoma 2 (Bcl-2) in PC-3 cells compared to DU145 and LNCaP cells. Consistently, Brassinin reduced the number of colonies and increased the sub-G1 population and terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL)-positive cells in the PC-3 cells. Of note, Brassinin suppressed the expressions of pyruvate kinase-M2 (PKM2), glucose transporter 1 (GLUT1), hexokinase 2 (HK2), and lactate dehydrogenase (LDH) as glycolytic proteins in the PC-3 cells. Furthermore, Brassinin significantly reduced the expressions of SIRT1, c-Myc, and β-catenin in the PC-3 cells and also disrupted the binding of SIRT1 with β-catenin, along with a protein-protein interaction (PPI) score of 0.879 and spearman's correlation coefficient of 0.47 being observed between SIRT1 and β-catenin. Of note, Brassinin significantly increased the reactive oxygen species (ROS) generation in the PC-3 cells. Conversely, ROS scavenger NAC reversed the ability of Brassinin to attenuate pro-PARP, pro-Caspase3, SIRT1, and β-catenin in the PC-3 cells. Taken together, these findings support evidence that Brassinin induces apoptosis via the ROS-mediated inhibition of SIRT1, c-Myc, β-catenin, and glycolysis proteins as a potent anticancer candidate.

Role of Plant-Derived Flavonoids in Cancer Treatment

Flavonoids are polyphenolic phytochemicals, which occur naturally in plants and possess both anti-oxidant and pro-oxidant properties. Flavonoids are gaining increasing popularity in the pharmaceutical industry as healthy and cost-effective compounds. Flavonoids show beneficial pharmacological activities in the treatment and prevention of various types of diseases. They are natural and less toxic agents for cancer chemotherapy and radiotherapy via regulation of multiple cell signaling pathways and pro-oxidant effects. In this review, we have summarized the mechanisms of action of selected flavonoids, and their pharmacological implications and potential therapeutic applications in cancer therapy.

Anti-prostate cancer protection and therapy in the framework of predictive, preventive and personalised medicine — comprehensive effects of phytochemicals in primary, secondary and tertiary care

According to the GLOBOCAN 2020, prostate cancer (PCa) is the most often diagnosed male cancer in 112 countries and the leading cancer-related death in 48 countries. Moreover, PCa incidence permanently increases in adolescents and young adults. Also, the rates of metastasising PCa continuously grow up in young populations. Corresponding socio-economic burden is enormous: PCa treatment costs increase more rapidly than for any other cancer. In order to reverse current trends in exploding PCa cases and treatment costs, pragmatic decisions should be made, in favour of advanced populational screening programmes and effective anti-PCa protection at the level of the health-to-disease transition (sub-optimal health conditions) demonstrating the highest cost-efficacy of treatments. For doing this, the paradigm change from reactive treatments of the clinically manifested PCa to the predictive approach and personalised prevention is essential.

Phytochemicals are associated with potent anti-cancer activity targeting each stage of carcinogenesis including cell apoptosis and proliferation, cancer invasiveness and metastatic disease. For example, their positive effects are demonstrated for stabilising and restoring mitochondrial health quality, which if compromised is strongly associated with sub-optimal health conditions and strong predisposition to aggressive PCa sub-types. Further, phytochemicals significantly enhance response of cancer cells to anti-cancer therapies including radio- and chemotherapy. Evident plant-based mitigation of negative side-effects frequently observed for conventional anti-cancer therapies has been reported. Finally, dual anti-cancer and anti-viral effects of phytochemicals such as these of silibinin have been demonstrated as being highly relevant for improved PCa management at the level of secondary and tertiary care, for example, under pandemic conditions, since PCa-affected individuals per evidence are highly vulnerable towards COVID-19 infection.

Here, we present a comprehensive data analysis towards clinically relevant anti-cancer effects of phytochemicals to be considered for personalised anti-PCa protection in primary care as well as for an advanced disease management at the level of secondary and tertiary care in the framework of predictive, preventive and personalised medicine.

Chiral Flavonoids as Antitumor Agents

Flavonoids are a group of natural products with a great structural diversity, widely distributed in plant kingdom. They play an important role in plant growth, development and defense against aggressors. Flavonoids show a huge variety of biological activities such as antioxidant, anti-inflammatory, anti-mutagenic, antimicrobial and antitumor, being able to modulate a large diversity of cellular enzymatic activities. Among natural flavonoids, some classes comprise chiral molecules including flavanones, flavan-3-ols, isoflavanones, and rotenoids, which have one or more stereogenic centers. Interestingly, in some cases, individual compounds of enantiomeric pairs have shown different antitumor activity. In nature, these compounds are mainly biosynthesized as pure enantiomers. Nevertheless, they are often isolated as racemates, being necessary to carry out their chiral separation to perform enantioselectivity studies. Synthetic chiral flavonoids with promising antitumor activity have also been obtained using diverse synthetic approaches. In fact, several new chiral bioactive flavonoids have been synthesized by enantioselective synthesis. Particularly, flavopiridol was the first cyclin-dependent kinase (CDK) inhibitor which entered clinical trials. The chiral pool approaches using amino acid as chiral building blocks have also been reported to achieve small libraries of chrysin derivatives with more potent in vitro growth inhibitory effect than chrysin, reinforcing the importance of the introduction of chiral moieties to improve antitumor activity. In this work, a literature review of natural and synthetic chiral flavonoids with antitumor activity is reported for the first time.

Research progress of phenolic compounds regulating IL-6 to exert antitumor effects

Cytokine therapy, which activates the host immune system, has become an important and novel therapeutic approach to treat various cancers. Recent studies have shown that IL-6 is an important cytokine that regulates the homeostasis in vivo. However, excessive IL-6 plays a pathological role in a variety of acute and chronic inflammatory diseases, especially in cancer. IL-6 can transmit signals through JAK/STAT, RAS /MAPK, PI3K/ Akt, NF-κB, and other pathways to promote cancer progression. Phenolic compounds can effectively regulate the level of IL-6 in tumor cells and improve the tumor microenvironment. This article focuses on the phenolic compounds through the regulation of IL-6, participate in the prevention of cancer, inhibit the proliferation of cancer cells, reduce angiogenesis, improve therapeutic efficacy, and reduce side effects and other aspects. This will help to further advance research on cytokine therapy to reduce the burden of cancer and improve patient prognosis. However, current studies are mostly limited to animal and cellular experiments, and high-quality clinical studies are needed to further determine their antitumor efficacy in humans.

MicroRNAs and Natural Compounds Mediated Regulation of TGF Signaling in Prostate Cancer

Prostate cancer (PCa) is with rising incidence in male population globally. It is a complex anomaly orchestrated by a plethora of cellular processes. Transforming growth factor-beta (TGF-β) signaling is one of the key signaling pathways involved in the tumorigenesis of PCa. TGF-β signaling has a dual role in the PCa, making it difficult to find a suitable therapeutic option. MicroRNAs (miRNAs) mediated regulation of TGF-β signaling is responsible for the TGF-ß paradox. These are small molecules that modulate the expression of target genes and regulate cancer progression. Thus, miRNAs interaction with different signaling cascades is of great attention for devising new diagnostic and therapeutic options for PCa. Natural compounds have been extensively studied due to their high efficacy and low cytotoxicity. Here, we discuss the involvement of TGF-ß signaling in PCa with the interplay between miRNAs and TGF-β signaling and also review the role of natural compounds for the development of new therapeutics for PCa.

The role of visfatin and resistin in an in vitro model of obesity-induced invasive liver cancer

Obesity is associated with the development of liver disease and its progression to hepatocellular carcinoma. This link may be attributed to adipocytokines such as visfatin and resistin which have been shown to promote liver cancer incidence and progression. Studies have yet to determine the role of visfatin and resistin in liver cancer, specifically in the context of obesity. The objective of this study was to investigate the effect of neutralizing visfatin and resistin in obese (OB) or normal weight (NW) sera to determine the contribution of these proteins in obesity-induced invasive liver cancer. Sera from OB or NW males was used to determine the efficacy of neutralizing visfatin and resistin to reduce the obesity-induced liver cancer phenotype. HepG2 and SNU-449 cells were exposed to OB and NW sera ± antibodies for visfatin or resistin. The neutralizing antibodies differentially suppressed invasion, reactive oxygen species production, and matrix metalloproteinase-9 secretion. These changes corresponded with a decrease in phosphorylated extracellular signal-regulated kinases and protein kinase B in HepG2 cells, but differences were not observed in CAP1 or β-catenin. In conclusion, visfatin and resistin have differential roles in obesity-associated liver cancer and may be potential targets to reverse the impact of obesity on liver cancer progression.

Silibinin Augments the Antifibrotic Effect of Valsartan Through Inactivation of TGF-β1 Signaling in Kidney

Background

Chronic kidney disease (CKD) has become a major public health issue. Meanwhile, renal fibrosis caused by diabetic nephropathy can lead to CKD, regardless of the initial injury. It has been previously reported that silibinin or valsartan could relieve the severity of renal fibrosis. However, the effect of silibinin in combination with valsartan on renal fibrosis remains unclear.

Material and Methods

Proximal tubular cells (HK-2) were treated with TGF-β1 (5 ng/mL) to mimic in vitro model of fibrosis. The proliferation of HK-2 cells was tested by CCK-8. Epithelial-mesenchymal transition (EMT) and inflammation-related gene and protein expressions in HK-2 cells were measured by qRT-PCR and Western-blot, respectively. ELISA was used to test the level of TNF-αNF-A. Additionally, HFD-induced renal fibrosis mice model was established to investigate the effect of silibinin in combination with valsartan on renal fibrosis in vivo.

Results

Silibinin significantly increased the anti-fibrosis effect of valsartan in TGF-β1-treated HK-2 cells via inhibition of TGF-β1 signaling pathway. Furthermore, silibinin significantly enhanced the anti-fibrosis effect of valsartan on HFD-induced renal fibrosis in vivo through inactivation of TGF-β1 signaling pathway.

Conclusion

These data indicated that silibinin markedly increased anti-fibrosis effect of valsartan in vitro and in vivo. Thus, silibinin in combination with valsartan may act as a potential novel strategy to treat renal fibrosis caused by diabetic nephropathy.