Induction of Cell Cycle Arrest and Apoptosis by Physcion, an Anthraquinone Isolated From Rhubarb (Rhizomes of Rheum tanguticum), in MDA-MB-231 Human Breast Cancer Cells

Therapeutic Potential of 1,8-Dihydroanthraquinone Derivatives for Breast Cancer

Breast cancer (BC) is the most common malignancy among women worldwide. In recent years, significant progress has been made in BC therapy. However, serious side effects resulting from the use of standard chemotherapeutic drugs, as well as the phenomenon of multidrug resistance (MDR), limit the effectiveness of approved therapies. Advanced research in the BC area is necessary to create more effective and safer forms of therapy to improve the outlook for individuals diagnosed with this aggressive neoplasm. For decades, plants and natural products with anticancer properties have been successfully utilized in treating various medical conditions. Anthraquinone derivatives are tricyclic secondary metabolites of natural origin that have been identified in plants, lichens, and fungi. They represent a few botanical families, e.g., Rhamnaceae, Rubiaceae, Fabaceae, Polygonaceae, and others. The review comprehensively covers and analyzes the most recent advances in the anticancer activity of 1,8-dihydroanthraquinone derivatives (emodin, aloe-emodin, hypericin, chrysophanol, rhein, and physcion) applied both individually, or in combination with other chemotherapeutic agents, in in vitro and in vivo BC models. The application of nanoparticles for in vitro and in vivo evidence in the context of 1,8-dihydroanthraquinone derivatives was also described.

Cytotoxic and apoptotic potential of gemini-chrysophanol nanoparticles against human colorectal cancer HCT-116 cell lines

Background

Colorectal cancer is among the most common cancers and accounts for nearly 9% of all cancers in the world. Chrysophanol is a naturally occurring anthraquinone exerts a number of pharmacological activities such as anti-inflammation, anti-cancer, anti-bacterial, anti-viral, and anti-oxidant effects. This study aims to produce a novel gemini chrysophanol nanoparticles (Gemini-Chr NPs), and to evaluate its anti-cancer effect on the human colorectal cancer cell lines.

Methods

Gemini-Chr NPs were synthesized through nanoprecipitation method and characterized by dynamic light scattering and scanning electron microscopy, Anti-cancer activities were examined through MTT assay on HCT-116 cancer cells, apoptosis was investigated via Annexin V-FITC/PI dual stain assay. Furthermore, the expression of Bax, Bcl-2 and P53 genes were evaluated using real-time PCR and western blotting assay. 

Results

The average particle diameter of the synthesized Gemini-Chr NPs and zeta potential were recorded as 120 nm and 14.4 mV, respectively. In comparison to the normal cells, the cytotoxicity assay confirmed that Gemini-Chr NPs preferentially killed colorectal cancer cells via induction of apoptosis. Moreover, Gemini-Chr NPs could upregulate the expression of Bax in both cancerous and normal cells (p ≤ 0.05) and decreasing the Bcl-2 expression in only tumor cells (p ≤ 0.01), while the expression of P53 is modulated in tumor cells (p ≤ 0.05).

Conclusions

Gemini surfactants could be considered for efficient delivery and improvement of anti-cancer effect of chrysophanol. Gemini-Chr NPs might have the potential for developing novel therapeutic agent against colorectal cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-022-00597-z.

Extracts of Rheum palmatum and Aloe vera Show Beneficial Properties for the Synergistic Improvement of Oral Wound Healing

Various local and systemic factors compromise oral wound healing and may lead to wound dehiscence, inflammation, or ulcers. Currently, there is a lack of topical therapeutical options. Thus, this study aimed to investigate the effect of Aloe vera (AV) and Rheum palmatum root (RPR) on oral wound healing capacity in vitro. The effect of AV and RPR on human primary fibroblast viability and migration was studied by measuring metabolic activity and gap closure in a scratch assay. Furthermore, cell cycle distribution and cytoskeletal features were analyzed. Antimicrobial activity against the oral pathogen Porphyromonas gingivalis was evaluated by broth microdilution assay. AV and RPR increased fibroblast migration after single agent treatment. Synergistic effects of the plant extract combination were observed regarding cellular migration which were confirmed by calculation of the phenomenological combination index (pCI), whereas the cell cycle distribution was not influenced. Furthermore, the combination of AV and RPR showed synergistic antibacterial effects as determined by the fractional inhibitory concentration index. This study demonstrated that the combination of AV and RPR can promote the migration of human primary fibroblasts in vitro and exert antimicrobial efficacy against P. gingivalis, suggesting these compounds for the topical treatment of wound healing disorders.

Efficient Extraction of an Anthraquinone Physcion Using Response Surface Methodology (RSM) Optimized Ultrasound-Assisted Extraction Method from Aerial Parts of Senna occidentalis and Analysis by HPLC-UV

In this experiment, the Box–Behnken design (BBD) of the response surface methodology (RSM) was used to optimize the ultrasound-assisted extraction variables (liquid-to-solid ratio, extraction temperature, and time) to obtain the maximum yield of physcion from the methanol extract of S. occidentalis (aerial parts). The analysis of physcion in the extracts obtained by using the optimized extraction condition was carried out in a gradient system by the HPLC-UV method with 0.5% formic acid in ultra-pure water (Solvent A) and acetonitrile (Solvent B) in different ratios as the mobile phase. The optimal extraction conditions for the maximum physcion extraction were found as: a liquid-to-solid ratio of 20.16 mL/g, extraction temperature of 52.2 °C, and extraction time of 46.6 min. Under these optimal ultrasonic extraction conditions, the experimental yield (% w/w of the dried extract) of the physcion was found to be 2.43%, which agreed closely with the predicted value (2.41). The experimental value was consistent with the value predicted by the RSM model, thus validating the fitness of the employed model and the success of the RSM in optimizing the extraction conditions. In future, this optimized ultrasonic extraction condition can be used in the maximum extraction of physcion from marketed herbal supplements containing S. occidentalis as well as other Senna species.

A Network Pharmacology Analysis of the Systems-Perspective Anticancer Mechanisms of the Herbal Drug FDY2004 for Breast Cancer

Breast cancer is a malignant tumor with high incidence, prevalence, and mortality rates in women. In recent years, herbal drugs have been assessed as anticancer therapy against breast cancer, owing to their promising therapeutic effects and reduced toxicity. However, their pharmacological mechanisms have not been fully explored at the systemic level. Here, we conducted a network pharmacology analysis of the systems-perspective molecular mechanisms of FDY2004, an anticancer herbal formula that consists of Moutan Radicis Cortex, Persicae Semen , and Rhei Radix et Rhizoma, against breast cancer. We determined that FDY2004 may contain 28 active compounds that exert pharmacological effects by targeting 113 breast cancer-related human genes/proteins. Based on the gene ontology terms, the FDY2004 targets were involved in modulating biological processes such as cell growth, cell proliferation, and apoptosis. Pathway enrichment analysis identified various breast cancer-associated pathways that may mediate the anticancer activity of FDY2004, including the PI3K-Akt, MAPK, TNF, HIF-1, focal adhesion, estrogen, ErbB, NF-kappa B, p53, and VEGF signaling pathways. Thus, our analysis offers novel insights into the anticancer properties of herbal drugs for breast cancer treatment from a systemic perspective.

LncRNA-H19 gene plays a significant role in regulating glioma cell function

Background

Glioma is an aggressive adult primary cancer, and is characterized by low cure rate, poor prognosis, and high recurrence. The present study aimed to investigate the effect of lncRNA‐H19 gene silencing on glioma cell function.

Methods

lncRNA‐H19 interference vector (LV3‐si‐H19) and negative control vector (LV3‐NC) were stably transfected into U251 and U87‐MG cells, respectively. Quantitative real‐time PCR (qRT‐PCR) was performed to investigate the expression of lncRNA‐H19. Cell proliferation capacity was tested by adopting cell counting kit (CCK8), and propidium iodide (PI) was used for cell cycle analysis. Meanwhile, flow cytometry (FCM) method was used to investigate cell apoptosis, cell migration capacity was detected via wound healing and transwell experiments, and sphere‐forming ability was examined in serum‐free suspension culture. Additionally, glioma animal models were conducted through injecting U251 cells to estimate the effects of lncRNA‐H19 on glioma growth in vivo.

Results

Knocking down lncRNA‐H19 gene could effectively suppress the proliferation of U251 and U87‐MG cells. The knockdown of lncRNA‐H19 remarkably inhibited the migration and blocked cycle progressions of U251 and U87‐MG cells, yet, no obvious changes were observed in cell apoptosis. Besides, inhibiting lncRNA‐H19 expression could attenuate sphere‐forming function of U251 and U87‐MG cells. Additionally, tumor volume and weight were significantly reduced in rats injected with U251 LV‐si‐H19 cell line compared to untransfected and negative controls, when survival time was obviously prolonged in U251 LV‐si‐H19 injection groups.

Conclusion

LncRNA‐H19 gene plays a carcinogenic role in glioma progression via enhancing aggressive behavior of glioma cells.

A feedback loop between the androgen receptor and 6-phosphogluoconate dehydrogenase (6PGD) drives prostate cancer growth

Alterations to the androgen receptor (AR) signalling axis and cellular metabolism are hallmarks of prostate cancer. This study provides insight into both hallmarks by uncovering a novel link between AR and the pentose phosphate pathway (PPP). Specifically, we identify 6-phosphogluoconate dehydrogenase (6PGD) as an androgen-regulated gene that is upregulated in prostate cancer. AR increased the expression of 6PGD indirectly via activation of sterol regulatory element binding protein 1 (SREBP1). Accordingly, loss of 6PGD, AR or SREBP1 resulted in suppression of PPP activity as revealed by 1,2-¹³C₂ glucose metabolic flux analysis. Knockdown of 6PGD also impaired growth and elicited death of prostate cancer cells, at least in part due to increased oxidative stress. We investigated the therapeutic potential of targeting 6PGD using two specific inhibitors, physcion and S3, and observed substantial anti-cancer activity in multiple models of prostate cancer, including aggressive, therapy-resistant models of castration-resistant disease as well as prospectively collected patient-derived tumour explants. Targeting of 6PGD was associated with two important tumour-suppressive mechanisms: first, increased activity of the AMP-activated protein kinase (AMPK), which repressed anabolic growth-promoting pathways regulated by acetyl-CoA carboxylase 1 (ACC1) and mammalian target of rapamycin complex 1 (mTORC1); and second, enhanced AR ubiquitylation, associated with a reduction in AR protein levels and activity. Supporting the biological relevance of positive feedback between AR and 6PGD, pharmacological co-targeting of both factors was more effective in suppressing the growth of prostate cancer cells than single-agent therapies. Collectively, this work provides new insight into the dysregulated metabolism of prostate cancer and provides impetus for further investigation of co-targeting AR and the PPP as a novel therapeutic strategy.

Physcion Induces Potential Anticancer Effects in Cervical Cancer Cells

BACKGROUND

The extent of morphological and ultrastructural changes in HeLa cells was assessed by optical, fluorescence and electron microscopy after exposure to various concentrations of physcion, taking into account the biological properties of the test compound.

METHODS

Cell viability was assessed by MTT assay, while the cell cycle, LC3 expression, apoptosis, change of mitochondrial potential, Bcl-2 protein expression level and the level of reactive oxygen species were analyzed by flow cytometry.

RESULTS

As a result of physcion encumbrance, concentration-dependent inhibition of HeLa cell viability and the G0/G1 phase of the cell cycle was observed. Activation of the lysosomal system was also revealed, which was expressed by an increased number of lysosomes, autophage vacuoles and increased expression of the LC3 protein, a marker of the autophagy process. Transmission electron microscopy and fluorescence microscopy showed that physcion induced clear changes in cervical cancer cells, especially in the structure of the nucleus and mitochondria, which correlated with the production of reactive oxygen species by the test compound and indicated the induction of the oxidative process. At the same time, the pro-apoptotic effect of physcion was demonstrated, and this mechanism was dependent on the activation of caspases 3/7 and the reduction in Bcl-2 protein expression.

CONCLUSION

The obtained results indicate an antitumor mechanism of action of physcion, based on the induction of oxidative stress, autophagy and apoptosis.

Physcion and Physcion 8-O-β-D-glucopyranoside: Natural Anthraquinones with Potential Anticancer Activities

Nature has provided prodigious reservoirs of pharmacologically active compounds for drug development since times. Physcion and physcion 8-O-β-D-glucopyranoside (PG) are bioactive natural anthraquinones which exert anti-inflammatory and anticancer properties with minimum or no adverse effects. Moreover, physcion also exhibits anti-microbial and hepatoprotective properties, while PG is known to have anti-sepsis as well as ameliorative activities against dementia. This review aims to highlight the natural sources and anticancer activities of physcion and PG, along with associated mechanisms of actions. On the basis of the literature, physcion and PG regulate multitudinous cell signaling pathways through the modulation of various regulators of cell cycle, protein kinases, microRNAs, transcriptional factors, and apoptosis linked proteins resulting in the effective killing of cancerous cells in vitro as well as in vivo. Both compounds effectively suppress metastasis, furthermore, physcion acts as an inhibitor of 6PGD and also plays an important role in chemosensitization. This review article suggests that physcion and PG are potent anticancer drug candidates, but further investigations on their mechanism of action and pre-clinical trials are mandatory in order to comprehend the full potential of these natural cancer killers in anticancer remedies.

Polysaccharides extracted from Rheum tanguticum ameliorate radiation-induced enteritis via activation of Nrf2/HO-1

Radiation-induced enteritis is a major side effect in cancer patients undergoing abdominopelvic radiotherapy. The Nrf2/HO-1 pathway is a critical endogenous antioxidant stress pathway, but its precise role in radiation-induced enteritis remains to be clarified. Polysaccharides extracted from Rheum tanguticum (RTP) can protect the intestinal cells from radiation-induced damage, but the underlying mechanism is unknown. SD rats and IEC-6 cells were exposed to 12 or 10 Gy X-ray radiation. Rat survival, and histopathological and immunohistochemical profiles were analyzed at different time points. Indicators of oxidative stress and inflammatory response were also assessed. Cell viability, apoptosis and Nrf2/HO-1 expression were evaluated at multiple time points. Significant changes were observed in the physiological and biochemical indexes of rats after radiation, accompanied by significant oxidative stress response. The mRNA and protein expression of Nrf2 peaked at 12 h after irradiation, and HO-1 expression peaked at 48 h after irradiation. RTP administration reduced radiation-induced intestinal damage, upregulated Nrf2/HO-1, improved physiological indexes, significantly decreased apoptosis and inflammatory factors, and upregulated HO-1, particularly at 48 h after irradiation. In conclusion, Nrf2 is activated in the early stage of radiation-induced intestinal injury and plays a protective role. RTP significantly ameliorates radiation-induced intestinal injury via the regulation of Nrf2 and its downstream protein HO-1.

Mitochondrial Targeting in an Anti-Austerity Approach Involving Bioactive Metabolites Isolated from the Marine-Derived Fungus Aspergillus sp

The tumor microenvironment is a nutrient-deficient region that alters the cancer cell phenotype to aggravate cancer pathology. The ability of cancer cells to tolerate nutrient starvation is referred to as austerity. Compounds that preferentially target cancer cells growing under nutrient-deficient conditions are being employed in anti-austerity approaches in anticancer drug discovery. Therefore, in this study, we investigated physcion (1) and 2-(2',3-epoxy-1',3',5'-heptatrienyl)-6-hydroxy-5-(3-methyl-2-butenyl) benzaldehyde (2) obtained from a culture extract of the marine-derived fungus Aspergillus species (sp.), which were isolated from an unidentified marine sponge, as anti-austerity agents. The chemical structures of 1 and 2 were determined via spectroscopic analysis and comparison with authentic spectral data. Compounds 1 and 2 exhibited selective cytotoxicity against human pancreatic carcinoma PANC-1 cells cultured under glucose-deficient conditions, with IC₅₀ values of 6.0 and 1.7 µM, respectively. Compound 2 showed higher selective growth-inhibitory activity (505-fold higher) under glucose-deficient conditions than under general culture conditions. Further analysis of the mechanism underlying the anti-austerity activity of compounds 1 and 2 against glucose-starved PANC-1 cells suggested that they inhibited the mitochondrial electron transport chain.

Physcion Synergistically Enhances the Cytotoxicity of Sorafenib in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a common human malignancy. Physcion is a naturally occurring anthraquinone derivative found in plant and marine sources. Our previous studies have indicated that physcion could suppress tumor growth and induce apoptosis in HCC. This study was aimed to investigate the effect of a combination of physcion and sorafenib on HCC. Our findings indicated that physcion could significantly augment the antiproliferative and proapoptotic activities of sorafenib in vitro and in vivo. Mechanistically, the synergistic effect correlates with physcion-induced suppression of Notch3/AKT signaling. This preclinical evidence highlights the potential application of physcion in the treatment of HCC. Anat Rec, 302:2171-2177, 2019. © 2019 American Association for Anatomy.

Piceatannol-3-O-β-D-glucopyranoside (PG) exhibits in vitro anti-metastatic and anti-angiogenic activities in HT1080 malignant fibrosarcoma cells

BACKGROUND

Several components isolated from rhubarb, the root of Rheum undulatum L., including emodin, rhein, rhaponticin, and piceatannol, have been reported to induce cell death and inhibit metastasis in various types of cancer. Recently, piceatannol-3-O-β-D-glucopyranoside (PG) isolated from rhubarb was demonstrated to improve vascular dysfunction by inhibiting arginase activity.

PURPOSE

In this study, we examined the anti-cancer activities of PG, including effects on the proliferation, metastasis, and angiogenesis of endothelial and malignant cancer cells.

RESULTS

We found that PG did not affect the proliferation of human fibrosarcoma (HT1080) and human umbilical vein endothelial cells (HUVECs) at treatments up to 100  μM. However, PG efficiently suppressed the metastatic ability of HT1080 cells, as determined by scratch wound migration, transwell migration/invasion assay, and three-dimensional (3D) spheroid invasion assay. PG significantly suppressed the phorbol 12-myristate 13-acetate (PMA)-induced increase of matrix metalloproteinase (MMP)-9 expression as well as gelatinolytic MMP-9 activity, which are essential for cancer metastasis. In addition, PG treatment reduced the production of proangiogenic factors in HT1080 cells under normoxic and hypoxic conditions and suppressed hypoxia-induced activation of the hypoxia-inducible factor (HIF)-1α pathway. We also found that HUVEC angiogenic activity, including migration and tubular structure formation, were significantly reduced by PG treatment. Moreover, in an in ovo chick chorioallantoic membrane assay, spontaneous and vascular endothelial growth factor (VEGF)-induced vessel formation were significantly inhibited by PG treatment.

CONCLUSION

These results collectively indicate that PG has potent anti-metastatic and anti-angiogenic activities with no cytotoxicity. Thus, PG may be useful to limit the hyperplasia of malignant tumors and the spread of cancer to distant secondary organs.

The Influence of Compatibility of Rhubarb and Radix Scutellariae on the Pharmacokinetics of Anthraquinones and Flavonoids in Rat Plasma

BACKGROUND AND OBJECTIVES

Rhubarb-Radix scutellariae is a classic herb pair, which is commonly used to clear away heat and toxin in clinic. The aim of this study was to investigate the influence of compatibility of Rhubarb and Radix scutellariae on the pharmacokinetic behaviors of anthraquinones and flavonoids in rat plasma.

METHODS

Eighteen rats were randomly divided into three groups, and were orally administered Rhubarb and/or Radix scutellariae extracts. A sensitive and rapid UPLC-MS/MS method was developed and validated to determine the concentrations of baicalin, baicalein, wogonside, wogonin, rhein, and emodin in rat plasma. The concentrations of phase II conjugates of flavonoid aglycones and anthraquinone aglycones were also determined after hydrolyzing the plasma with sulfatase.

RESULTS

Compared with administration of Radix scutellariae alone, co-administration of Rhubarb significantly decreased the first maximum plasma concentration (C _max1) of baicalin, wogonside, and the phase II conjugates of baicalein, wogonin to 46.40, 61.27, 41.49, and 20.50%, respectively. The area under the plasma concentration-time curve from time zero to infinity (AUC_0-∞) was significantly decreased from 82.60 ± 20.22 to 51.91 ± 7.46 μM·h for rhein and 276.83 ± 98.02 to 175.42 ± 86.82 μM·h for the phase II conjugates of wogonin after compatibility. The time to reach the first maximum plasma concentration (T _max1) of anthraquinones was shortened and the second peak of anthraquinones disappeared after compatibility.

CONCLUSIONS

Compatibility of Rhubarb and Radix scutellariae can significantly affect the pharmacokinetic behaviors of characteristic constituents of the two herbs. The cause of these pharmacokinetic differences was further discussed combined with the in vivo ADME (absorption, disposition, metabolism, and excretion) processes of anthraquinones and flavonoids.

Emodin, Physcion, and Crude Extract of Rhamnus sphaerosperma var. pubescens Induce Mixed Cell Death, Increase in Oxidative Stress, DNA Damage, and Inhibition of AKT in Cervical and Oral Squamous Carcinoma Cell Lines

There have been few studies on the pharmacological properties of Rhamnus sphaerosperma var. pubescens, a native Brazilian species popularly known as “fruto-de-pombo.” The aim of this study was to investigate the scavenging capacity of emodin, physcion, and the ethanolic crude extract of Rhamnus sphaerosperma var. pubescens against reactive oxygen and nitrogen species, as well as their role and plausible mechanisms in prompting cell death and changes in AKT phosphorylation after cervical (SiHa and C33A) and oral (HSC-3) squamous cell carcinoma treatments. Emodin was shown to be the best scavenger of NO^• and O₂^•−, while all samples were equally effective in HOCl/OCl⁻ capture. Emodin, physcion, and the ethanolic extract all exhibited cytotoxic effects on SiHa, C33A, HSC-3, and HaCaT (immortalized human keratinocytes, nontumorigenic cell line), involving mixed cell death (apoptosis and necrosis) independent of the caspase activation pathway. Emodin, physcion, and the ethanolic extract increased intracellular oxidative stress and DNA damage. Emodin decreased the activation of AKT in all tumor cells, physcion in HSC-3 and HaCaT cells, and the ethanolic extract in C33A and HaCaT cells, respectively. The induction of cancer cell death by emodin, physcion, and the ethanolic crude extract of Rhamnus sphaerosperma var. pubescens was related to an increase in intracellular oxidative stress and DNA damage and a decrease in AKT activation. These molecules are therefore emerging as interesting candidates for further study as novel options to treat cervical and oral carcinomas.

Physcion induces apoptosis through triggering endoplasmic reticulum stress in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common and aggressive malignancies. The current study aimed to investigate the effect of physcion, a major active ingredient in several traditional herbal medicinal plants, for the treatment of HCC. Our data showed that physcion markedly induced apoptosis in human HCC cell lines Huh7 and Bel7402. The pro-apoptotic role of physcion on HCC cells was mediated by mitochondria dysfunction, which was caused by activation of endoplasmic reticulum(ER) stress. Moreover, our findings revealed that physcion stimulated ER stress by activating AMPK signaling. Besides in HCC cell lines, the anti-cancer activity of physcion was also examined in a xenograft mice model, which showed that physcion could significantly suppressed tumor growth. In conclusion, our results indicated that physcion can be considered as a potential chemotherapeutic agent in the treatment of HCC.

Rheum australe, an endangered high-value medicinal herb of North Western Himalayas: a review of its botany, ethnomedical uses, phytochemistry and pharmacology

Rheum australe (Himalayan Rhubarb) is a multipurpose, endemic and endangered medicinal herb of North Western Himalayas. It finds extensive use as a medicinal herb since antiquity in different traditional systems of medicine to cure a wide range of ailments related to the circulatory, digestive, endocrine, respiratory and skeletal systems as well as to treat various infectious diseases. The remedying properties of this plant species are ascribed to a set of diverse bioactive secondary metabolite constituents, particularly anthraquinones (emodin, chrysophanol, physcion, aloe-emodin and rhein) and stilbenoids (piceatannol, resveratrol), besides dietary flavonoids known for their putative health benefits. Recent studies demonstrate the pharmacological efficacy of some of these metabolites and/or their derivatives as lead molecules for the treatment of various human diseases. Present review comprehensively covers the literature available on R. australe from 1980 to early 2018. The review provides up-to-date information available on its botany for easy identification of the plant, and origin and historical perspective detailing its trade and commerce. Distribution, therapeutic potential in relation to traditional uses and pharmacology, phytochemistry and general biosynthesis of major chemical constituents are also discussed. Additionally, efficient and reproducible in vitro propagation studies holding vital significance in preserving the natural germplasm of the plant and for its industrial exploitation have also been highlighted. The review presents a detailed perspective for future studies to conserve and sustainably make use of this endangered plant species at a commercial scale.

Novel bisnaphthalimidopropyl (BNIPs) derivatives as anticancer compounds targeting DNA in human breast cancer cells

Bisnaphthalimidopropyl (BNIP) derivatives are a family of compounds that exert anti-cancer activities in vitro and, according to previous studies, variations in the linker sequence have increased their DNA binding and cytotoxic activities. By modifying the linker sequence of bisnaphthalimidopropyl diaminodicyclohexylmethane (BNIPDaCHM), a previously synthesised BNIP derivative with anti-cancer properties, three novel BNIP derivatives were designed. Bisnaphthalimidopropyl-piperidylpropane (BNIPPiProp), a structural isomer of BNIPDaCHM, bisnaphthalimidopropyl ethylenedipiperidine dihydrobromide (BNIPPiEth), an isoform of BNIPDaCHM with a shorter linker chain, and (trans(trans))-bisnaphthalimidopropyl diaminodicyclohexylmethane (trans,trans-BNIPDaCHM), a stereoisomer of BNIPDaCHM, were successfully synthesised (72.3-29.5% yield) and characterised by nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS). Competitive displacement of ethidium bromide (EtBr) and UV binding studies were used to study the interactions of BNIP derivatives with Calf Thymus DNA. The cytotoxicity of these derivatives was assessed against human breast cancer MDA-MB-231 and SKBR-3 cells by MTT assay. Propidium iodide (PI) flow cytometry was conducted in order to evaluate the cellular DNA content in both breast cancer cell lines before and after treatment with BNIPs. The results showed that all novel BNIPs exhibit strong DNA binding properties in vitro, and strong cytotoxicity, with IC₅₀ values in the range of 0.2-3.3 μM after 24 hours drug treatment. Two of the novel BNIP derivatives, BNIPPiEth and trans,trans-BNIPDaCHM, exhibited greater cytotoxicity against the two breast cancer cell lines studied, compared to BNIPDaCHM. By synthesising enantiopures and reducing the length of the linker sequence, the cytotoxicity of the BNIP derivatives was significantly improved compared to BNIPDaCHM, while maintaining DNA binding and bis-intercalating properties. In addition, cell cycle studies indicated that trans,trans-BNIPDaCHM, the most cytotoxic BNIP derivative, induced sub-G1 cell cycle arrest, indicative of apoptotic cell death. Based on these findings, further investigation is under way to assess the potential efficacy of trans,trans-BNIPDaCHM and BNIPPiEth in treating human breast cancer.

Chrysophanol inhibits proliferation and induces apoptosis through NF-κB/cyclin D1 and NF-κB/Bcl-2 signaling cascade in breast cancer cell lines

Chrysophanol is an anthraquinone compound, which exhibits anticancer effects on certain types of cancer cells. However, the effects of chrysophanol on human breast cancer remain to be elucidated. The aim of the present study was to clarify the role of chrysophanol on breast cancer cell lines MCF-7 and MDA-MB-231, and to identify the signal transduction pathways regulated by chrysophanol. MTT assay and flow cytometric analysis demonstrated that chrysophanol inhibited cell proliferation, and cell cycle progression in a dose-dependent manner. The expression of cell cycle-associated cyclin D1 and cyclin E were downregulated while p27 expression was upregulated following chrysophanol treatment at the mRNA, and protein levels. The Annexin V/propidium iodide staining assay results revealed that apoptosis levels increased following chrysophanol treatment. Chrysophanol upregulated caspase 3 and poly (ADP-ribose) polymerase cleavage in both cell lines. Furthermore, chrysophanol enhanced the effect of paclitaxel on breast cancer cell apoptosis. In addition, chrysophanol downregulated apoptosis regulator Bcl-2 protein, and transcription factor p65 and IκB phosphorylation. Inhbition of nuclear factor (NF)-κB by ammonium pyrrolidine dithiocarbamate diminished the effect of chrysophanol on apoptosis and associated proteins. In conclusion, the results of the current study demonstrated that chrysophanol effectively suppresses breast cancer cell proliferation and facilitates chemosentivity through modulation of the NF-κB signaling pathway.

Physcion blocks cell cycle and induces apoptosis in human B cell precursor acute lymphoblastic leukemia cells by downregulating HOXA5

Acute lymphoblastic leukemia (ALL) presents the most common type of malignancy in children and ranks the third most common cancer in adults. This study is aimed to investigate the anti-leukemia activity of physcion in ALL. Our results have showed that physcion could significantly suppress cell growth, induce apoptosis and blocked cell cycle progression in vitro. Mechanistically, we found that physcion downregulated the expression of HOXA5, which is responsible for the anti-leukemia activity of physcion. To verify this finding, siRNA targeting HOXA5 and overexpressing plasmid were used to repress HOXA5 expression and introduce ectopic overexpression of HOXA5 in ALL cell lines, respectively. Our results showed that overexpression of HOXA5 significantly abrogated the inducing effect of physcion on apoptosis and cell cycle blockasde. In contrast, knockdown of HOXA5 by siRNA enhanced the anti-tumor effect of physcion on ALL cell lines. Our results provided experimental base for the use of physcion in the treatment of ALL.

Gold-chrysophanol nanoparticles suppress human prostate cancer progression through inactivating AKT expression and inducing apoptosis and ROS generation in vitro and in vivo

Controlled releasing of regulations remains the most convenient method to deliver various drugs. In the present study, we precipitated gold nanoparticles with chrysophanol. The gold-chrysophanol into poly (DL-lactide-co-glycolide) nanoparticles was loaded and the biological activity of chrysophanol nanoparticles on human LNCap prostate cancer cells, was tested to acquire the sustained releasing property. The circular dichroism spectroscopy indicated that chrysophanol nanoparticles effectively resulted in conformational alterations in DNA and regulated different proteins associated with cell cycle arrest. The reactive oxygen species (ROS), apoptosis, cell cycle, DNA damage, Cyto-c and caspase-3 activity were analyzed, and the expression levels of different anti- and pro-apoptotic were studied using immunoblotting analysis. The cytotoxicity assay suggested that chrysophanol nanoparticles preferentially killed prostate cancer cells in comparison to the normal cells. Chrysophanol nanoparticles reduced histone deacetylases (HDACs) to suppress cell proliferation and induce apoptosis by arresting the cell cycle in sub-G phase. In addition, the cell cycle-related proteins, including p27, CHK1, cyclin D1, CDK1, p-AMP-activated protein kinase (AMPK) and p-protein kinase B (AKT), were regulated by chrysophanol nanoparticles to prevent human prostate cancer cell progression. Chrysophanol nanoparticles induced apoptosis in LNCap cells by promoting p53/ROS crosstalk to prevent proliferation. Pharmacokinetic study in mice indicated that chrysophanol nanoparticle injection showed high bioavailability compared to the free chrysophanol. Also, in vivo study revealed that chrysophanol nanoparticles obviously reduced tumor volume and weight. In conclusion, the data above suggested that chrysophanol nanoparticles might be effective to prevent human prostate cancer progression.

Physcion induces apoptosis in hepatocellular carcinoma by modulating miR-370

Hepatocellular carcinoma (HCC) is one of the most common and aggressive malignancies. The current study is designed to explore the role of physcion, a major active ingredient in several traditional herbal medicinal plants, for the treatment of HCC. HCC cell lines, SMMC7721 and HepG2, were treated with physcion and its apoptosis-inducing effect was examined. Both in vitro and in vivo results from the present study demonstrated that physcion treatment resulted in apoptotic cell death in HCC cells via upregulation of miR-370. Furthermore, our findings showed that the physcion modulated the level of miR-370 through AMPK/Sp1/DNMT1 signaling. Taken together, these results showed that physcion exerts anti-tumor effect against HCC, which may be a potential agent for the adjunct chemotherapy.

Physcion, a naturally occurring anthraquinone derivative, induces apoptosis and autophagy in human nasopharyngeal carcinoma

AIM

Physcion is a major bioactive ingredient in the traditional Chinese medicine Radix et Rhizoma Rhei, which has an anthraquinone chemical structure and exhibits a variety of pharmacological activities including laxative, hepatoprotective, anti-inflammatory, anti-microbial and anti-proliferative effects. In this study we investigated the effect of physcion on human nasopharyngeal carcinoma in vitro and in vivo, as well as the mechanisms underlying the anti-tumor action.

METHODS

The nasopharyngeal carcinoma cell line CNE2 was treated with physcion, and cell viability was detected using MTT and colony formation assays. Flow cytometry was used to assess the cell cycle arrest, mitochondrial membrane potential loss, apoptosis, autophagy and intracellular ROS generation. Apoptotic cell death was also confirmed by a TUNEL assay. The expression of target or marker molecules was determined using Western blotting. The activity of caspase-3, 8, and 9 was detected with an ELISA kit. A xenograft murine model was used to evaluate the in vivo anti-tumor action of physcion, the mice were administered physcion (10, 20 mg·kg-1·d-1, ip) for 30 d.

RESULTS

Treatment with physcion (5, 10, and 20 μmol/L) dose-dependently suppressed the cell viability and colony formation in CNE2 cells. Physcion (10 and 20 μmol/L) dose-dependently blocked cell cycle progression at G1 phase and induced both caspase-dependent apoptosis and autophagy in CNE2 cells. Furthermore, physcion treatment induced excessive ROS generation in CNE2 cells, and subsequently disrupted the miR-27a/ZBTB10 axis, resulting in repression of the transcription factor Sp1 that was involved in physcion-induced apoptosis and autophagy. Moreover, physcion-induced autophagy acted as a pro-apoptotic factor, and possibly contributed to physcion-induced apoptosis. In the xenograft murine model, administration of physcion dose-dependently suppressed the tumor growth without affecting the body weight. Furthermore, the anti-tumor effects of physcion were correlated with downregulation of Sp1 and suppression of miR-27a in the tumor tissues.

CONCLUSION

Physcion induces apoptosis and autophagy in human nasopharyngeal carcinoma by targeting Sp1, which was mediated by ROS/miR-27a/ZBTB10 signaling. The results suggest that physcion is a promising candidate for the treatment of human nasopharyngeal carcinoma.

The anti-tumor effect and bioactive phytochemicals of Hedyotis diffusa willd on ovarian cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Hedyotis diffusa willd (HDW) is a widely used medicinal herb in China. It processed various medicinal properties including antioxidative, anti-inflamatory and anti-cancer effects. This study aimed to investigate the anti-tumor effects of HDW on ovarian cancer cells and the underlying mechanisms as well as identify the bioactive compounds.

MATERIALS AND METHODS

Effects of HDW on the viability of ovarian cancer A2780 cells were detected by MTT assay. Apoptosis was detected by cell morphologic observation through DAPI staining and flow cytometry analysis. The migration of ovarian cancer cells which exposed to HDW were detected by wound healing and transwell assays. The protein levels of caspase 3/9, Bcl-2 and MMP-2/9 in human ovarian cancer cells treated with HDW were assessed by western blotting analysis. The potential bioactive compounds were characterized by HPLC-Q-TOF-MS.

RESULTS

HDW significantly inhibited the growth of A2780 ovarian cancer cells and induced apoptosis. The induction of apoptosis by HDW was associated with down-regulation of anti-apoptotic protein Bcl-2 and the activation of caspase 3/9. Wound healing and transwell chamber assays indicated HDW suppressed the migration of ovarian cancer cells. HDW dramatically decreased MMP-2/9 expression. A HPLC-Q-TOF-MS analysis of HDW indicated the presence of 13 flavonoids compounds and one anthraquinone compound, which may contribute to the anticancer activity of the HDW.

CONCLUSIONS

HDW effectively restricted the growth of ovarian cancer cells and induced apoptosis through the mitochondria-associated apoptotic pathway. Furthermore, HDW suppressed the migration of ovarian cancer cells through down-regulation of MMP-2 and MMP-9 expression. These results showed that HDW hold potential therapeutic effect for ovarian cancer patients.

Upregulating miR-146a by physcion reverses multidrug resistance in human chronic myelogenous leukemia K562/ADM cells

The aim of this study was to evaluate the role of miR-146a in the drug resistance of chronic myelogenous leukemia (CML) cells (K562/ADM) and to investigate the reversal effect of physcion, a natural compound, on the multidrug-resistance in CML. Our results showed that miR-146a was significantly downregulated in drug-resistant K562 cells and the overexpression of miR-146a in K562/ADM cells could restore the sensitivity to adriamycin (ADM). In addition, our results showed that the downregulation of miR-146a was associated with increase in CXCR4 expression, which was a direct target of miR-146a. Moreover, our findings also provided experimental evidence that physcion could enhance the anti-proliferative effect of ADM in K562/ADM cells by upregulating miR-146a. In conclusion, this present study showed that miR-146a conferred ADM resistance in CML cells and physcion could improve the sensitivity of K562/ADM cells by enhancing apoptosis via upregulating miR-146a.

Is Low Non-Lethal Concentration of Methylmercury Really Safe? A Report on Genotoxicity with Delayed Cell Proliferation

Human exposure to relatively low levels of methylmercury is worrying, especially in terms of its genotoxicity. It is currently unknown as to whether exposure to low levels of mercury (below established limits) is safe. Genotoxicity was already shown in lymphocytes, but studies with cells of the CNS (as the main target organ) are scarce. Moreover, disturbances in the cell cycle and cellular proliferation have previously been observed in neuronal cells, but no data are presently available for glial cells. Interestingly, cells of glial origin accumulate higher concentrations of methylmercury than those of neuronal origin. Thus, the aim of this work was to analyze the possible genotoxicity and alterations in the cell cycle and cell proliferation of a glioma cell line (C6) exposed to a low, non-lethal and non-apoptotic methylmercury concentration. Biochemical (mitochondrial activity) and morphological (integrity of the membrane) assessments confirmed the absence of cell death after exposure to 3 μM methylmercury for 24 hours. Even without promoting cell death, this treatment significantly increased genotoxicity markers (DNA fragmentation, micronuclei, nucleoplasmic bridges and nuclear buds). Changes in the cell cycle profile (increased mitotic index and cell populations in the S and G2/M phases) were observed, suggesting arrest of the cycle. This delay in the cycle was followed, 24 hours after methylmercury withdrawal, by a decrease number of viable cells, reduced cellular confluence and increased doubling time of the culture. Our work demonstrates that exposure to a low sublethal concentration of MeHg considered relatively safe according to current limits promotes genotoxicity and disturbances in the proliferation of cells of glial origin with sustained consequences after methylmercury withdrawal. This fact becomes especially important, since this cellular type accumulates more methylmercury than neurons and displays a vital role protecting the CNS, especially in chronic intoxication with this heavy metal.

Upregulation of Human ST8Sia VI (α2,8-Sialyltransferase) Gene Expression by Physcion in SK-N-BE(2)-C Human Neuroblastoma Cells

In this research, we firstly demonstrated that physcion, an anthraquinone derivative, specifically increased the expression of the human α2,8-sialyltransferase (hST8Sia VI) gene in SK-N-BE(2)-C human neuroblastoma cells. To establish the mechanism responsible for the up-regulation of hST8Sia VI gene expression in physcion-treated SK-N-BE(2)-C cells, the putative promoter region of the hST8Sia VI gene was functionally characterized. Promoter analysis with serially truncated fragments of the 5′-flanking region showed that the region between −320 and −240 is crucial for physcion-induced transcription of hST8Sia VI in SK-N-BE(2)-C cells. Putative binding sites for transcription factors Pax-5 and NF-Y are located at this region. The Pax-5 binding site at −262 to −256 was essential for the expression of the hST8Sia VI gene by physcion in SK-N-BE(2)-C cells. Moreover, the transcription of hST8Sia VI induced by physcion in SK-N-BE(2)-C cells was inhibited by extracellular signal-regulated protein kinase (ERK) inhibitor U0126 and p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580, but not c-Jun N-terminal kinase (JNK) inhibitor SP600125. These results suggest that physcion upregulates hST8Sia VI gene expression via ERK and p38 MAPK pathways in SK-N-BE(2)-C cells.

Induction of G1-phase cell cycle arrest and apoptosis pathway in MDA-MB-231 human breast cancer cells by sulfated polysaccharide extracted from Laurencia papillosa

Background

Marine algae consumption is linked to law cancer incidences in countries that traditionally consume marine products. Hence, Phytochemicals are considered as potential chemo-preventive and chemotherapeutic agents against cancer. We investigated the effects of the algal sulfated polysaccharide extract (ASPE) from the red marine alga L. papillosa on MDA-MB-231 human breast cancer cell line.

Methods

Flow cytometry analysis was performed to study the cell viability, cell cycle arrest and apoptosis. Changes in the expression of certain genes associated with cell cycle regulation was conducted by PCR real time analyses. Further investigations on apoptotic molecules was performed by ROS measurement and protein profiling.

Results

ASPE at low doses (10 µg/ml), inhibited cell proliferation, and arrested proliferating MDA-MB-231 cells at G1-phase. However, higher doses (50 µg/ml), triggered apoptosis in those cells. The low dose of ASPE also caused up-regulation of Cip1/p21 and Kip1/p27 and down-regulation of cyclins D1, D2, and E1 transcripts and their related cyclin dependent kinases: Cdk2, Cdk4, and Cdk6. The higher doses of ASPE initiated a dose-dependent apoptotic death in MDA-MB-231 by induction of Bax transcripts, inhibition of Bcl-2 and cleavage of Caspase-3 protein. Over-generation of reactive oxygen species (ROS) were also observed in MDA-MB-231 treated cells.

Conclusions

These findings indicated that ASPE induces G1-phase arrest and apoptosis in MDA-MB-231 cells. ASPE may serve as a potential therapeutic agent for breast cancer.

Physcion inhibits the metastatic potential of human colorectal cancer SW620 cells in vitro by suppressing the transcription factor SOX2

AIM

Physcion, an anthraquinone derivative, exhibits hepatoprotective, anti-inflammatory, anti-microbial and anti-cancer activities. In this study we examined whether and how physcion inhibited metastatic potential of human colorectal cancer cells in vitro.

METHODS

Human colorectal cancer cell line SW620 was tested. Cell migration and invasion were assessed using a wound healing and Transwell assay, respectively. The expression levels of transcription factor SOX2 in the cells were modulated with shRNA targeting SOX2 and SOX2 overexpressing plasmid. The expression of target molecules involved in epithelial-mesenchymal transition (EMT) process and the signaling pathways was determined with Western blots or qRT-PCR. ROS levels were measured using DCF-DA.

RESULTS

Physcion (2.5, 5 mol/L) did not affect the cell viability, but dose-dependently inhibited the cell adhesion, migration and invasion. Physcion also inhibited the EMT process in the cells, as evidenced by the increased epithelial marker E-cadherin expression, and by decreased expression of mesenchymal markers N-cadherin, vimentin, fibronectin and α-SMA, as well as transcriptional repressors Snail, Slug and Twist. Physcion suppressed the expression of SOX2, whereas overexpression of SOX2 abrogated the inhibition of physcion on metastatic behaviors. Physcion markedly increased ROS production and phosphorylation of AMPK and GSK3β in the cells, whereas the AMPK inhibitor compound C or the ROS inhibitor NAC abolished the inhibition of physcion on metastatic behaviors.

CONCLUSION

Physcion inhibits the metastatic potential of human colorectal cancer cells in vitro via activating ROS/AMPK/GSK3β signaling pathways and suppressing SOX2.

Anti-cancer Activity of Osmanthus matsumuranus Extract by Inducing G2/M Arrest and Apoptosis in Human Hepatocellular Carcinoma Hep G2 Cells

BACKGROUND

Osmanthus matsumuranus, a species of Oleaceae, is found in East Asia and Southeast Asia. The bioactivities of O. matsumuranus have not yet been fully understood. Here, we studied on the molecular mechanisms underlying anti-cancer effect of ethanol extract of O. matsumuranus (EEOM).

METHODS

Inhibitory effect of EEOM on cell growth and proliferation was determined by WST assay in various cancer cells. To investigate the mechanisms of EEOM-mediated cytotoxicity, HepG2 cells were treated with various concentration of EEOM and analyzed the cell cycle arrest and apoptosis induction by flow cytometry, Western blot analysis, 4,6-diamidino-2-phenylindole (DAPI) staining and DNA fragmentation.

RESULTS

EEOM showed the cytotoxic activities in a dose-dependent manner in various cancer cell lines but not in normal cells, and HepG2 cells were most susceptible to EEOM-induced cytotoxicity. EEOM induced G2/M arrest in HepG2 cells associated with decreased expression of cyclin-dependent kinase 1 (CDK1), cyclin A and cylcin B, and increased expression of phospho-checkpoint kinase 2, p53 and CDK inhibitor p21. Immunofluorescence staining showed that EEOM-treated HepG2 increased doublet nuclei and condensed actin, resulting in cell rounding. Furthermore, EEOM-mediated apoptosis was determined by Annexin V staining, chromatin condensation and DNA fragmentation. EEOM caused upregulation of FAS and Bax, activation of caspase-3, -8, -9, and fragmentation of poly ADP ribose polymerase.

CONCLUSIONS

These results suggest that EEOM efficiently inhibits proliferation of HepG2 cells by inducing both G2/M arrest and apoptosis via intrinsic and extrinsic pathways, and EEOM may be used as a cancer chemopreventive agent in the food or nutraceutical industry.