Non-homologous end joining pathway is the major route of protection against 4β-hydroxywithanolide E-induced DNA damage in MCF-7 cells

Withanolides: Promising candidates for cancer therapy

Natural products have played a significant role throughout history in the prevention and treatment of numerous diseases, particularly cancers. As a natural product primarily derived from various medicinal plants in the Withania genus, withanolides have been shown in several studies to exhibit potential activities in cancer treatment. Consequently, understanding the molecular mechanism of withanolides could herald the discovery of new anticancer agents. Withanolides have been studied widely, especially in the last 20 years, and attracted the attention of numerous researchers. Currently, over 1200 withanolides have been classified, with approximately a quarter of them having been reported in the literature to be able to modulate the survival and death of cancer cells through multiple avenues. To what extent, though, has the anticancer effects of these compounds been studied? How far are they from being developed into clinical drugs? What are their potential, characteristic features, and challenges? In this review, we elaborate on the current knowledge of natural compounds belonging to this class and provide an overview of their natural sources, anticancer activity, mechanism of action, molecular targets, and implications for anticancer drug research. In addition, direct targets and clinical research to guide the design and implementation of future preclinical and clinical studies to accelerate the application of withanolides have been highlighted.

Effects of Dietary Phytochemicals on DNA Damage in Cancer Cells

With the increasing incidence of cancer worldwide, the prevention and treatment of cancer have garnered considerable scientific attention. Traditional chemotherapeutic drugs are highly toxic and associated with substantial side effects; therefore, there is an urgent need for developing new therapeutic agents. Dietary phytochemicals are important in tumor prevention and treatment because of their low toxicity and side effects at low concentrations; however, their exact mechanisms of action remain obscure. DNA damage is mainly caused by physical or chemical factors in the environment, such as ultraviolet light, alkylating agents and reactive oxygen species that cause changes in the DNA structure of cells. Several phytochemicals have been shown inhibit the occurrence and development of tumors by inducing DNA damage. This article reviews the advances in phytochemical research; particularly regarding the mechanisms related to DNA damage and provide a theoretical basis for future chemoprophylaxis research.

Identification of Key Pathways Involved in White Strain of Hypsizygus marmoreus Extracts-Induced Cell Death of Human Hepatoma Hep3B Cells by Next Generation Sequencing

White strain of Hypsizygus marmoreus is named as white genius mushroom (WGM) and is a popular food in Taiwan. We have confirmed the cytotoxicity of WGM extracts on human Hep3B liver cancer cells. A total of 8711 significantly differential genes were identified through large-scale transcriptome sequencing. According to the KEGG pathway enrichment analysis, autophagy, mitophagy and apoptosis pathways were identified as significant in WGM extracts-treated cells. WGM extracts induced a dose-dependent generation of reactive oxygen species (ROS) and membrane-enclosed vacuoles in Hep3B cells. The inhibition of ROS by the ROS scavengers blocked the induction of cell death and vacuoles formation. We suggested that the cell death and membrane-enclosed vacuoles induced by WGM extracts are dependent on ROS production in Hep3B cells. (2E,6E)-3,7,11,15,19,23,27,31,35-Nonamethylhexatriaconta-2,6,34-triene-1,11,15,19,23,27,31-heptol and (18:2) lysophosphatidylcholine were identified in WGM extracts. In addition to being a very popular edible mushrooms, WGM may be developed into a dietary supplement or dietary chemopreventive agent for the cancer treatment.

Ahovegbe LY, Ali MS, Tusiimire J, Ogwang PE, Kadima JN, Agaba AG. Chemical constituents and evidence-based pharmacological properties of Physalis peruviana L.: An overview

Physalis peruviana L. is among plant species possessing evident nutritional, nutraceutical, and commercial interests. This review highlights the complexity of the chemical composition supporting the multiple pharmacotherapeutic indications and dietary values of this plant through evidence-based studies from Google Scholar, PubMed/Medline, SciFinder, Science Direct, Scopus, the Wiley online library, and Web of Science. The literature mentions at least 40 compounds isolated from different parts; others are still under investigation. High yields in carotenoids, amino acids, minerals, vitamin C, vitamin E, and essential fatty acids have healthy nutritional benefits. Various phytoconstituents, particularly withanolides, exhibit anti-carcinogenic, anti-inflammatory, and antidiabetic potentials, as well as cardiovascular and liver protective effects. Prospective studies reveal that the leaves would also provide various beneficial bioactive chemicals worth being isolated. However, clinical evidence-based studies are seldom. Therefore, adequate pharmaceutical formulations and more in-depth controlled clinical trials are needed to fill the gap.

The synthesis and cytotoxic activity of derivatives of 4β-hydroxywithanolide E

4β-Hydroxywithanolide E, which can be obtained in large amounts from the Physalis genus, possessed anti-proliferative effects on a variety of human cancer cell lines. For discussing its anti-tumor structure-activity relationship, a series of 4β-hydroxywithanolide E derivatives (1-17) were synthesized and evaluated for their antitumor activity in vitro towards acute promyelocytic leukemia NB4 cell line by the Alarma blue assay. Cytotoxicity data revealed that the enone structure and C-4 hydroxyl substituents of ring A, together with the side chain (C-20-C-28) play an important effect on the cytotoxicity.

Physalis peruviana-Derived 4β-Hydroxywithanolide E, a Novel Antagonist of Wnt Signaling, Inhibits Colorectal Cancer In Vitro and In Vivo

Deregulation of the Wnt signaling pathway leads to colorectal cancer progression. Natural dietary compounds serve as promising candidates for development as chemopreventive agents by suppressing the Wnt/β-catenin signaling pathway. Physalis peruviana-derived 4βHWE showed a significant inhibitory activity with a calculated IC₅₀ of 0.09 μΜ in a screening of novel inhibitors of Wnt signaling with the dual-luciferase reporter assay. This study investigated the anti-tumor effect of 4βHWE and the potential Wnt signaling inhibitory mechanism. Both the western blot analysis and immunofluorescence assay showed that 4βHWE promoted the phosphorylation and degradation of β-catenin and the subsequent inhibition of its nuclear translocation to attenuate the endogenous Wnt target gene expression in colorectal cancer (CRC) cells. The cell viability assay indicated that 4βHWE preferentially inhibited the proliferation of CRC compared with CCD-841-CoN, a normal human colonic epithelial cell line. 4βHWE-mediated G0/G1 cell cycle arrest and apoptosis induction contributed to the suppression of the proliferation of CRC in the cell cycle and Annexin V-FITC/Propidium Iodide apoptosis analysis. Moreover, in vivo, 4βHWE dramatically inhibited tumor growth in HCT116 xenografts by attenuating the Wnt/β-catenin signaling pathway. In conclusion, our study suggested that 4βHWE could be of potential use in anti-tumor agent development as a novel Wnt signaling inhibitor.

Different effects of 4β-hydroxywithanolide E and withaferin A, two withanolides from Solanaceae plants, on the Akt signaling pathway in human breast cancer cells

BACKGROUND

Triple-negative breast cancer (TNBC) represents a clinical challenge because it lacks sensitivity to hormone therapy or other available molecule-targeted agents. In addition, TNBC frequently exhibits over-activation of the PI3K/Akt survival pathway that can contribute to chemotherapy resistance. 4β-Hydroxywithanolide E (4-HW) and withaferin A (WA) are two withanolides from Solanaceae plants that exhibit promising anticancer activity in vitro and in vivo.

PURPOSE

The aim of this study is to investigate and compare the effects of 4-HW and WA on TNBC cells and underling mechanisms.

STUDY DESIGN/METHODS

The anticancer effects of 4-HW and WA were evaluated by cell viability, cell cycle arrest, and apoptosis assays. PI3K/Akt signaling and the expression of survivin, Bcl-2 family proteins and cyclin-dependent kinase inhibitors were evaluated by Western blot. The role of PI3K/Akt signaling in the withanolides-induced anticancer effects was examined by using a PI3K inhibitor and overexpression of a constitutively active form of Akt.

RESULTS

In TNBC MDA-MB-231 cells, 4-HW and WA displayed different kinetic effect on cell availability. Cell cycle analysis revealed that 4-HW induced the G₁-phase arrest while WA caused the G₂/M-phase block. Both withanolides induced apoptosis, but WA also caused necrosis. 4-HW inhibited the PI3K/Akt pathway and survivin expression as well as up-regulated the cyclin-dependent kinase inhibitors p21 and p27. In contrast, WA is a more potent inhibitor of Hsp90 and elicited Akt activation at low doses but inhibited Akt signaling at higher doses by depleting the Akt protein. The PI3K inhibitor LY294002 mimicked the effects of 4-HW and potentiated the cytotoxic activity of WA. In contrast, overexpressing a constitutively active form of myristoylated Akt rescue cancer cells from 4-HW-induced cell death.

CONCLUSION

The withanolides 4-HW and WA potently inhibit the viability of TNBC cells through induction of cell cycle arrest and apoptosis/necrosis. The PI3K/Akt pathway plays distinct roles in cancer cells respond to 4-HW and WA. These results suggest the potential applications of the withanolides for the treatment of TNBC.

Oxidative stress-modulating drugs have preferential anticancer effects - involving the regulation of apoptosis, DNA damage, endoplasmic reticulum stress, autophagy, metabolism, and migration

To achieve preferential effects against cancer cells but less damage to normal cells is one of the main challenges of cancer research. In this review, we explore the roles and relationships of oxidative stress-mediated apoptosis, DNA damage, ER stress, autophagy, metabolism, and migration of ROS-modulating anticancer drugs. Understanding preferential anticancer effects in more detail will improve chemotherapeutic approaches that are based on ROS-modulating drugs in cancer treatments.

4β-Hydroxywithanolide E selectively induces oxidative DNA damage for selective killing of oral cancer cells

Reactive oxygen species (ROS) induction had been previously reported in 4β-hydroxywithanolide (4βHWE)-induced selective killing of oral cancer cells, but the mechanism involving ROS and the DNA damage effect remain unclear. This study explores the role of ROS and oxidative DNA damage of 4βHWE in the selective killing of oral cancer cells. Changes in cell viability, morphology, ROS, DNA double strand break (DSB) signaling (γH2AX foci in immunofluorescence and DSB signaling in western blotting), and oxidative DNA damage (8-oxo-2'deoxyguanosine [8-oxodG]) were detected in 4βHWE-treated oral cancer (Ca9-22) and/or normal (HGF-1) cells. 4βHWE decreased cell viability, changed cell morphology and induced ROS generation in oral cancer cells rather than oral normal cells, which were recovered by a free radical scavenger N-acetylcysteine (NAC). For immunofluorescence, 4βHWE also accumulated more of the DSB marker, γH2AX foci, in oral cancer cells than in oral normal cells. For western blotting, DSB signaling proteins such as γH2AX and MRN complex (MRE11, RAD50, and NBS1) were overexpressed in 4βHWE-treated oral cancer cells in different concentrations and treatment time. In the formamidopyrimidine-DNA glycolyase (Fpg)-based comet assay and 8-oxodG-based flow cytometry, the 8-oxodG expressions were higher in 4βHWE-treated oral cancer cells than in oral normal cells. All the 4βHWE-induced DSB and oxidative DNA damage to oral cancer cells were recovered by NAC pretreatment. Taken together, the 4βHWE selectively induced DSB and oxidative DNA damage for the ROS-mediated selective killing of oral cancer cells.

Withanolides from Aeroponically Grown Physalis peruviana and Their Selective Cytotoxicity to Prostate Cancer and Renal Carcinoma Cells

Investigation of aeroponically grown Physalis peruviana resulted in the isolation of 11 new withanolides, including perulactones I-L (1-4), 17-deoxy-23β-hydroxywithanolide E (5), 23β-hydroxywithanolide E (6), 4-deoxyphyperunolide A (7), 7β-hydroxywithanolide F (8), 7β-hydroxy-17-epi-withanolide K (9), 24,25-dihydro-23β,28-dihydroxywithanolide G (10), and 24,25-dihydrowithanolide E (11), together with 14 known withanolides (12-25). The structures of 1-11 were elucidated by the analysis of their spectroscopic data, and 12-25 were identified by comparison of their spectroscopic data with those reported. All withanolides were evaluated for their cytotoxic activity against a panel of tumor cell lines including LNCaP (androgen-sensitive human prostate adenocarcinoma), 22Rv1 (androgen-resistant human prostate adenocarcinoma), ACHN (human renal adenocarcinoma), M14 (human melanoma), SK-MEL-28 (human melanoma), and normal human foreskin fibroblast cells. Of these, the 17β-hydroxywithanolides (17-BHWs) 6, 8, 9, 11-13, 15, and 19-22 showed selective cytotoxic activity against the two prostate cancer cell lines LNCaP and 22Rv1, whereas 13 and 20 exhibited selective toxicity for the ACHN renal carcinoma cell line. These cytotoxicity data provide additional structure-activity relationship information for the 17-BHWs.

The Roles of 4β-Hydroxywithanolide E from Physalis peruviana on the Nrf2-Anti-Oxidant System and the Cell Cycle in Breast Cancer Cells

4[Formula: see text]-Hydroxywithanolide E is an active component of the extract of Physalis peruviana that has been reported to exhibit antitumor effects. Although the involvement of reactive oxygen species (ROS) production and the ataxia-telangiectasia mutated protein (ATM)-dependent DNA damage signaling pathway in 4[Formula: see text]-hydroxywithanolide E-induced apoptosis of breast cancer MCF-7 cells was demonstrated in our previous study, the relationship between ROS production and the cellular defense system response in 4[Formula: see text]-hydroxywithanolide E-induced cell death requires further verification. The present study suggests that ROS play an important role in 4[Formula: see text]-hydroxywithanolide E-induced MCF-7 cell death in which anti-oxidants, such as glutathione or N-acetylcysteine, can resist the 4[Formula: see text]-hydroxywithanolide E-induced accumulation of ROS and cell death. Furthermore, N-acetylcysteine or glutathione can reverse the 4[Formula: see text]-hydroxywithanolide E-induced changes in the cell cycle distribution and the expression of cell cycle regulators. We found that the 4[Formula: see text]-hydroxywithanolide E-induced ROS accumulation was correlated with the upregulation of Nrf2 and Nrf2-downstream genes, such as antioxidative defense enzymes. In general, the activity of Nrf2 is regulated by the Ras signalling pathway. However, we demonstrated that Nrf2 was activated during 4[Formula: see text]-hydroxywithanolide E-induced MCF-7 cell death in spite of the 4[Formula: see text]-hydroxywithanolide E-induced inhibition of the Ras/Raf/ERK pathway. The activity and protein expression of superoxide dismutase and catalase were involved in the 4[Formula: see text]-hydroxywithanolide E-induced ROS production in MCF-7 cells. Furthermore, 4[Formula: see text]-hydroxywithanolide E was demonstrated to significantly reduce the sizes of the tumor nodules in the human breast cancer MDA-MB231 xenograft tumor model.

Hazards of low dose flame-retardants (BDE-47 and BDE-32): Influence on transcriptome regulation and cell death in human liver cells

We have evaluated the in vitro low dose hepatotoxic effects of two flame-retardants (BDE-47 and BDE-32) in HepG2 cells. Both congeners declined the viability of cells in MTT and NRU cell viability assays. Higher level of intracellular reactive oxygen species (ROS) and dysfunction of mitochondrial membrane potential (ΔΨm) were observed in the treated cells. Comet assay data confirmed the DNA damaging potential of both congeners. BDE-47 exposure results in the appearance of subG1 apoptotic peak (30.1%) at 100 nM, while BDE-32 arrested the cells in G2/M phase. Among the set of 84 genes, BDE-47 induces downregulation of majority of mRNA transcripts, whilst BDE-32 showed differential expression of transcripts in HepG2. The ultrastructural analysis revealed mitochondrial swelling and degeneration of cristae in BDE-47 and BDE-32 treated cells. Overall our data demonstrated the hepatotoxic potential of both congeners via alteration of vital cellular pathways.

Raf/ERK/Nrf2 signaling pathway and MMP-7 expression involvement in the trigonelline-mediated inhibition of hepatocarcinoma cell migration

Background

Trigonelline occurs in many dietary food plants and has been found to have anti-carcinogenic activity. Trigonelline is also found in coffee which is one of the most widely consumed beverages. Many epidemiological studies have reported that coffee consumption has an inverse relationship with the risk of cirrhosis or hepatocellular carcinoma. It would be interesting to investigate whether trigonelline is an ideal chemoprevent agent to prevent cancer progression.

Methods

The protein expression was performed by western blotting. The trigonelline content in snow pea (Pisum sativum) was analyzed by high-performance liquid chromatography (HPLC). The migratory activity of human hepatocarcinoma cells (Hep3B) was assessed by using a wound migration assay. The percentage of each phase in the cell cycle was analyzed on a FACScan flow cytometer. Gene expression was detected by real-time reverse transcriptase-polymerase chain reaction techniques. Native gel analysis was performed to analyze the activity of superoxide dismutase (SOD), catalase and glutathione peroxidase.

Results

According to the data of HPLC analysis, P. sativum, which is a popular vegetable, has relatively high content of trigonelline. Our findings suggest that trigonelline is an efficient compound for inhibiting Hep3B cell migration. Trigonelline inhibited the migration of hepatoma cells at concentrations of 75–100 µM without affecting proliferation. Raf/ERK/Nrf2 protein levels and further downstream antioxidative enzymes activity, such as SOD, catalase, and glutathione peroxidase, significantly decreased after treatment with 100 µM of trigonelline for 24 h. The migration inhibition of trigonelline is also related to its ability to regulate the matrix metalloproteinases 7 (MMP-7) gene expression.

Conclusions

In this study, protein kinase Cα (PKCα) and Raf/ERK/Nrf2 signaling pathway and MMP-7 gene expression were involved in the trigonelline-mediated migration inhibition of Hep3B cells. We also demonstrated that trigonelline inhibits Hep3B cell migration through downregulation of nuclear factor E2-related factor 2–dependent antioxidant enzymes activity. This study analyzed the trigonelline content in a popular vegetable, snow pea, as a representative proof to prove that trigonelline is often found in the daily intake of food. Our finding suggested that trigonelline should be a useful chemopreventive agent derived from the daily intake of food to prevent cancer progression.