Aloe emodin induces G2/M cell cycle arrest and apoptosis via activation of caspase-6 in human colon cancer cells

Anthraquinones from the roots of Morinda scabrida Craib exhibit antiproliferative activity against A549 lung cancer cells and antitubulin polymerization

Six anthraquinones were isolated from Morinda scabrida Craib, an unexplored species of Morinda found in the tropical forest of Thailand. All six anthraquinones showed cytotoxicity against A549 lung cancer cells, with the most active compound, nordamnacanthal (MS01), exhibiting the IC50 value of 16.3 ± 2.5 μM. The cytotoxic effect was dose-dependent and led to cell morphological changes characteristic of apoptosis. In addition, flow cytometric analysis showed dose-dependent apoptosis induction and the G2/M phase cell cycle arrest, which was in agreement with the tubulin polymerization inhibitory activity of MS01. Molecular docking analysis illustrated the binding between MS01 and the α/β-tubulin heterodimer at the colchicine binding site, and UV-visible absorption spectroscopy revealed the DNA binding capacity of MS01.

Structural Characterization and Anticancer Activity of a New Anthraquinone from Senna velutina (Fabaceae)

In this study, a novel compound was isolated, identified, and its chemical structure was determined from the extract of the roots of Senna velutina. In addition, we sought to evaluate the anticancer potential of this molecule against melanoma and leukemic cell lines and identify the pathways of cell death involved. To this end, a novel anthraquinone was isolated from the barks of the roots of S. velutina, analyzed by HPLC-DAD, and its molecular structure was determined by nuclear magnetic resonance (NMR). Subsequently, their cytotoxic activity was evaluated by the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) method against non-cancerous, melanoma, and leukemic cells. The migration of melanoma cells was evaluated by the scratch assay. The apoptosis process, caspase-3 activation, analysis of mitochondrial membrane potential, and measurement of ROS were evaluated by flow cytometry technique. In addition, the pharmacological cell death inhibitors NEC-1, RIP-1, BAPTA, Z-VAD, and Z-DEVD were used to confirm the related cell death mechanisms. With the results, it was possible to elucidate the novel compound characterized as 2'-OH-Torosaol I. In normal cells, the compound showed no cytotoxicity in PBMC but reduced the cell viability of all melanoma and leukemic cell lines evaluated. 2'-OH-Torosaol I inhibited chemotaxis of B16F10-Nex2, SK-Mel-19, SK-Mel-28 and SK-Mel-103. The cytotoxicity of the compound was induced by apoptosis via the intrinsic pathway with reduced mitochondrial membrane potential, increased levels of reactive oxygen species, and activation of caspase-3. In addition, the inhibitors demonstrated the involvement of necroptosis and Ca²⁺ in the death process and confirmed caspase-dependent apoptosis death as one of the main programmed cell death pathways induced by 2'-OH-Torosaol I. Taken together, the data characterize the novel anthraquinone 2'-OH-Torosaol I, demonstrating its anticancer activity and potential application in cancer therapy.

Caspase-6 is a key regulator of cross-talk signal way in PANoptosis in cancer

Cysteinyl aspartate specific proteinase (caspase)-6 belongs to the caspase family and plays a vital role in mediating cell death. Under certain conditions, three pathways of programmed cell death (PCD), including apoptosis, necroptosis and pyroptosis (PANoptosis), transform one way into another, with enormous therapeutic potential. Initially, scholars reported that caspase-6 is a caspase executor that mediates apoptosis. With the ceaseless exploration of the PCD types, studies have demonstrated that caspase-6 mediates pyroptosis by regulating gasdermin D and mediates necroptosis by regulating mixed lineage kinase domain-like. By regulating PANoptosis, caspase-6 plays a crucial role in tumorigenesis in humans and mediates anti-tumour immunity. Therefore, a comprehensive understanding of caspase-6 function in cancer via PANoptosis is important for the prevention and therapy of tumours. This article summarized the function of caspase-6 in PANoptosis and its impact on cancer development, providing targets and strategies for tumour treatment.

Traditional Chinese medicine for colorectal cancer treatment: potential targets and mechanisms of action

Colorectal cancer (CRC) is a disease with complex pathogenesis, it is prone to metastasis, and its development involves abnormalities in multiple signaling pathways. Surgery, chemotherapy, radiotherapy, target therapy, and immunotherapy remain the main treatments for CRC, but improvement in the overall survival rate and quality of life is urgently needed. Traditional Chinese medicine (TCM) has a long history of preventing and treating CRC. It could affect CRC cell proliferation, apoptosis, cell cycle, migration, invasion, autophagy, epithelial-mesenchymal transition, angiogenesis, and chemoresistance by regulating multiple signaling pathways, such as PI3K/Akt, NF-κB, MAPK, Wnt/β-catenin, epidermal growth factor receptors, p53, TGF-β, mTOR, Hedgehog, and immunomodulatory signaling pathways. In this paper, the main signaling pathways and potential targets of TCM and its active ingredients in the treatment of CRC were systematically summarized, providing a theoretical basis for treating CRC with TCM and new ideas for further exploring the pathogenesis of CRC and developing new anti-CRC drugs.

Antimicrobial and Cytotoxic Potential of Helminthosporin from Rumex abyssiniscus Jacq. Discovered as a Novel Source of Syringic Acid and Bis(2-ethyloctyl) Phthalate

Rumex abyssinicus Jacq. is a perennial medicinal herb widely used in traditional medicine to treat many diseases. Phytochemicals of the plant were isolated using column chromatography and thin layer chromatography techniques. Extract, fractions and pure compounds were screened for antimicrobial activity against sensitive and multi-drug resistant microbes and their cytotoxicity was performed on different cancer cell lines. The mechanism of action of purified helminthosporin as well as the potent fraction containing a mixture of two compounds was assessed. Fraction R7C3 was the most potent antibacterial with the lowest MIC value of 0.12 µg/mL. Helminthosporin was the most potent compound with the lowest MIC value of 1.95 µg/mL. The compound was more potent than the antibiotic chloramphenicol against multi-drug resistant (MDR) bacteria with MIC equal to 16 µg/mL. The fraction and helminthosporin were shown to destroy the cell wall of the yeast and bacteria, and DNA fragmentation effect on the genome of Candida albicans and Bacillus cereus. Helminthosporin was the most cytotoxic compound with IC₅₀ ˂ 10 µM. Fraction R7C3 showed the most potent cytotoxic effects on all cancer cell lines, with IC₅₀ ranging from ˂1 to 4.35 ng/mL. Our study is the first report on the mechanism of action of helminthosporin, a potent candidate in the development of new drugs against multi-resistant bacteria and cancer cells. In addition, this study uncovered Rumex abyssinicus as a new source of syringic acid and bis(2-ethyloctyl) phthalate.

The Role of Caspase Family in Acute Brain Injury: The Potential Therapeutic Targets in the Future

The caspase family is commonly involved in the pathophysiology of acute brain injury (ABI) through complex apoptotic, pyroptotic, and inflammatory pathways. Current translational strategies for caspase modulation in ABI primarily focus on caspase inhibitors. Because there are no caspase-inhibiting drugs approved for clinical use on the market, the development of caspase inhibitors remains an attractive challenge for researchers and clinicians. Therefore, we conducted the present review with the aim of providing a comprehensive introduction of caspases in ABI. In this review, we summarized the available evidence and potential mechanisms regarding the biological function of caspases. We also reviewed the therapeutic effects of caspase inhibitors on ABI and its subsequent complications. However, various important issues remain unclear, prompting further verification of the efficacy and safety regarding clinical application of caspase inhibitors. We believe that our work will be helpful to further understand the critical role of the caspase family and will provide novel therapeutic potential for ABI treatment.

Advances in Understanding the Role of Aloe Emodin and Targeted Drug Delivery Systems in Cancer

Cancer is one of the important causes of death worldwide. Despite remarkable improvements in cancer research in the past few decades, several cancer patients still cannot be cured owing to the development of drug resistance. Natural sources might have prominence as potential drug candidates. Among the several chemical classes of natural products, anthraquinones are characterized by their large structural variety, noticeable biological activity, and low toxicity. Aloe emodin, an anthraquinone derivative, is a natural compound found in the roots and rhizomes of many plants. This compound has proven its antineoplastic, anti-inflammatory, antiangiogenic, and antiproliferative potential as well as ability to prevent cancer metastasis and potential in reversing multidrug resistance of cancer cells. The anticancer property of aloe emodin, a broad-spectrum inhibitory agent of cancer cells, has been detailed in many biological pathways. In cancer cells, these molecular mechanisms consist of inhibition of cell growth and proliferation, cell cycle arrest deterioration, initiation of apoptosis, antimetastasis, and antiangiogenic effect. In accordance with the strategy of developing potential drug candidates from natural products, aloe emodin's low bioavailability has been tried to be overcome by structural modifications and nanocarrier systems. Consequently, this review summarizes the antiproliferative and anticarcinogenic properties of aloe emodin, as well as the enhanced activity of its derivatives and the advantages of drug delivery systems on bioavailability.

Aloe and its Effects on Cancer: A Narrative Literature Review

Many years ago, Aloe Vera was cited to have a lot of therapeutic properties including; anti-microbial, anti-viral, anti-cancer, anti-oxidant, anti-inflammatory, skin protection, wound healing, and regulation of blood glucose and cholesterol. However, Aloe could present some side effects. This review focused on the latest discoveries regarding the therapeutic role of Aloe plant or its compounds on the acquired biological capabilities for tumour growth and progression namely; evading growth suppressor, avoiding immune destruction, enabling replicative immortality, tumour promoting inflammation, activating invasion and metastasis, inducing angiogenesis, genome instability and mutation, resisting cell death, deregulating cellular energetics and sustaining proliferating signalling. It clarified the anti-cancer activities it exerts on different types of cancer and also highlighted some pro-oncogenic pathways that can be disrupted by different compounds of Aloe.

Natural substances to potentiate canonical glioblastoma chemotherapy

Glioblastoma multiforme (GBM) is the most frequent primary malignant brain tumour prevalent in humans, that exhibits aggressive cell proliferation and rapid invasion of normal brain tissue. Despite aggressive therapeutic approaches consisting of maximum safe surgical resection followed by radio-chemotherapy with temozolomide (TMZ), more than 95% of GBM patients die within 5 years after diagnosis. In most cases, the therapy is not able to counteract the growth and invasiveness of the tumour, which relapses after an interval of time that varies from patient to patient. An increasing number of evidence indicates that natural substances exhibited effective anti-tumour functions and might be successfully used in the treatment of GBM. This review summarizes some natural substances: lactoferrin, hispolon, aloe-emodin and tea tree oil; all these show a growth inhibition and synergistic effect when together with TMZ, (the most commonly used alkylating drug for the treatment of glioblastoma) were administered to U87MG glioblastoma cell line in vitro and in murine animal model. U87MG cell growth was monitored by daily cell count after treatments with the substances mentioned above and growth analysis showed that all drugs significantly decrease proliferation of U87MG in a time- and dose-dependent manner. FACS analysis demonstrates a block of cell cycle in S, G2/M or G0/G1 phases. These substances mediate multiple processes including apoptosis by releasing the inducing factor: PARP. Natural compounds, in combination with conventional chemotherapy TMZ, are a powerful approach to improve the effectiveness of brain cancer treatment.

Ursolic Acid Regulates Cell Cycle and Proliferation in Colon Adenocarcinoma by Suppressing Cyclin B1

Aims: The biological functions of cyclin B1 (CCNB1) in colon adenocarcinoma (COAD) will be explored in this study. Furthermore, the therapeutic effects and potential molecular mechanisms of ursolic acid (UA) in COAD cells will also be investigated in vitro.

Methods: COAD data were obtained from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. Differentially expressed genes (DEGs) were determined with differential analysis. The biological functions of CCNB1 were analyzed through the GeneCards, the Search Tool for the Retrieval of Interacting Genes (STRING), and the Database for Annotation, Visualization, and Integrated Discovery (DAVID) databases. Therapeutic effects of UA on COAD cell lines HCT-116 and SW-480 were analyzed by CCK-8 and high-content screening (HCS) imaging assay. Flow cytometry was utilized to detect cell cycle changes of SW-480 and HCT-116 cells. Levels of mRNA and expression proteins of HCT-116, SW-480, and normal colon epithelial cells NCM-460 were determined by qRT-PCR and western blot.

Results: CCNB1 was highly expressed and acted as an oncogene in COAD patients. CCNB1 and its interacting genes were significantly enriched in the cell cycle pathway. UA effectively inhibited the proliferation and injured COAD cells. In addition, UA arrested cell cycle of COAD cells in S phase. With regard to the molecular mechanisms of UA, we demonstrated that UA can significantly downregulate CCNB1 and its interacting genes and proteins, including CDK1, CDC20, CCND1, and CCNA2, which contributed to cell cycle blocking and COAD treatment.

Conclusion: Results from this study revealed that UA possesses therapeutic effects on COAD. The anti-COAD activities of UA are tightly related to suppression of CCNB1 and its interacting targets, which is crucial in abnormal cell cycle process.

Drug Delivery Systems of Natural Products in Oncology

In recent decades, increasing interest in the use of natural products in anticancer therapy field has been observed, mainly due to unsolved drug-resistance problems. The antitumoral effect of natural compounds involving different signaling pathways and cellular mechanisms has been largely demonstrated in in vitro and in vivo studies. The encapsulation of natural products into different delivery systems may lead to a significant enhancement of their anticancer efficacy by increasing in vivo stability and bioavailability, reducing side adverse effects and improving target-specific activity. This review will focus on research studies related to nanostructured systems containing natural compounds for new drug delivery tools in anticancer therapies.

Aloe-Emodin Induces Breast Tumor Cell Apoptosis through Upregulation of miR-15a/miR-16-1 That Suppresses BCL2

PURPOSE

Aloe-emodin (AE) is a natural compound derived from aloe vera and palmatum rhubarb and shows anticancer activities in various cancers. Bcl-2 family is the main regulator of cell death or cell survival. This study describes the effects of AE on proliferation of breast tumor (BT) cells.

METHODS

MCF-10A, MCF-10AT, MCF-7, and MDA-MB-231 cell lines were exposed to AE. Cell proliferation and apoptosis were assessed by CCK-8 and flow cytometry. Protein levels were measured by Western blotting. The levels of mRNA and miRNA were examined by RT-PCR. Bioinformatics was applied to screen miRNAs that bind to 3'-UTR of mRNA.

RESULTS

The results showed that AE selective activity inhibited the proliferation and induced apoptosis of MCF-10AT and MCF-7 cells but exhibited no significant inhibition in MCF10A and MDA-MB-231 cells. Mechanistically, AE dose-dependently decreased the protein expression of Bcl-2 and Bcl-xl, while it increased Bax protein expression in MCF-10AT and MCF-7 cells. The levels of Bcl-xl and Bax mRNA were altered by AE treatment, which was consistent with the protein expression results. However, Bcl-2 mRNA levels were not affected in either cell line, suggesting that AE may modulate the protein translation of Bcl-2 through miRNAs. In all candidate miRNAs that bind to 3'-UTR of Bcl-2, miR-15a and miR-16-1 were dose-dependently downregulated by AE. Moreover, inhibition of miR-15a/16-1 could eliminate the inhibition of MCF-10AT and MCF-7 cells growth by AE and could reverse the downregulation of AE-induced Bcl-2 protein level.

CONCLUSION

Our research provides an important basis that AE induces BT cell apoptosis through upregulation of miR-15a/miR-16-1 that suppresses BCL2.

Aloe-emodin: A review of its pharmacology, toxicity, and pharmacokinetics

Aloe-emodin is a naturally anthraquinone derivative and an active ingredient of Chinese herbs, such as Cassia occidentalis, Rheum palmatum L., Aloe vera, and Polygonum multiflorum Thunb. Emerging evidence suggests that aloe-emodin exhibits many pharmacological effects, including anticancer, antivirus, anti-inflammatory, antibacterial, antiparasitic, neuroprotective, and hepatoprotective activities. These pharmacological properties lay the foundation for the treatment of various diseases, including influenza virus, inflammation, sepsis, Alzheimer's disease, glaucoma, malaria, liver fibrosis, psoriasis, Type 2 diabetes, growth disorders, and several types of cancers. However, an increasing number of published studies have reported adverse effects of aloe-emodin. The primary toxicity among these reports is hepatotoxicity and nephrotoxicity, which are of wide concern worldwide. Pharmacokinetic studies have demonstrated that aloe-emodin has a poor intestinal absorption, short elimination half-life, and low bioavailability. This review aims to provide a comprehensive summary of the pharmacology, toxicity, and pharmacokinetics of aloe-emodin reported to date with an emphasis on its biological properties and mechanisms of action.

Isorhamnetin in Tsoong blocks Hsp70 expression to promote apoptosis of colon cancer cells

The roots of Codonopis bulleynana Forest ex diels (cbFed), locally known as Tsoong, have been used as a tonic food. Tsoong has wide range of pharmacological effects, including anticancer efficacy. In the present study, the anticancer activity of Tsoong and its potential molecular mechanisms were investigated. Isorhamnetin, a flavonol aglycone, is important compound and metabolite in Tsoong. It can promote apoptosis of colon cancer cells through up-regulating apoptosis-related genes (Apaf1, Casp3 and Casp9) because it blocks Hsp70 genes (Hspa1a, Hspa1b and Hspa8). These were verified by in vitro and in vivo experiments. In vitro, cell counting kit-8 (CCK-8) assays and flow cytometry in HCT116 and SW480 colon cancer cell were used to assess the anti-proliferation and apoptosis-promoting activities of Tsoong. In vivo, the antitumor effect of Tsoong was assessed in colon cancer-bearing nude mice as a xenograft model. These results show that Isorhamnetin is very critical in Tsoong because Tsoong can down-regulate Hsp70 genes and promote apoptosis of colon cancer cells by inhibiting Hsp70 largely due to the efficacy of Isorhamnetin. Our results may ultimately help in the development of diagnostic and therapeutic strategies to control this devastating disease.

Aloe-emodin attenuates myocardial infarction and apoptosis via up-regulating miR-133 expression

Aloe-emodin (AE) is an anthraquinone derived from rhubarb and has a variety of pharmacological actions. However, the role of AE in regulating ischemic heart diseases is still unclear. The present study investigated the effect of AE on cardiac injuries induced by myocardial infarction (MI) in vivo and oxidative insults in vitro and explored the mechanisms involved. TUNEL and Flow cytometry were performed to measure cell apoptosis. Western blot analysis was employed to detect expression of Bcl-2, Bax and Caspase-3 proteins. Real-time PCR was used to quantify the microRNAs levels. Our data showed that AE protected neonatal rat ventricular myocytes (NRVMs) from hydrogen peroxide (H₂O₂) induced apoptosis and significantly inhibited H₂O₂-induced reactive oxygen species (ROS) elevation. Furthermore, AE treatment significantly reversed H₂O₂-induced upregulation of Bax/Bcl-2 and the loss of mitochondrial membrane potential. In vivo, AE treatment significantly reduced infarct size, ameliorated impaired cardiac function and obviously decreased cardiac apoptosis and oxidative stress in MI mice heart. Meanwhile, AE restored H₂O₂-induced downregulation of miR-133, and transfection with miR-133 inhibitor abolished the anti-apoptotic and anti-oxidative effects of AE. Moreover, AE prevented H₂O₂-induced increase in caspase-3 activity, which was diminished by application of miR-133 inhibitor. Our results indicate that AE protectes against myocardial infarction via the upregulation of miR-133, inhibition of ROS production and suppression of caspase-3 apoptotic signaling pathway.

The research on the mechanism of Tsoong inhibiting for colon cancer

The roots of Codonopis bulleynana Forest ex diels (cbFed), locally known as Tsoong, have been used as a tonic food. Tsoong has wide range of pharmacological effects, including anticancer effects. In the present study, the anticancer activity of Tsoong and its potential molecular mechanisms were investigated. Using high throughput sequencing the apoptotic pathway was ranked as one of the most important pathways and the differential expressions of apoptosis-related genes such as Casp3, Casp6 and Apaf1 were identified. The following experiments were qRT-PCR which were used to verify the genes. In vitro, cell counting kit-8 (CCK-8) assays and flow cytometry in HCT116 and SW480 colon cancer cell were used to assess the anti-proliferation and apoptosis-promoting activities of Tsoong. In vivo, the antitumor effect of Tsoong was assessed in colon cancer-bearing nude mice as a xenograft model. H&E staining was performed with oxaliplatin set as a positive control. The results showed that Tsoong up-regulated apoptosis-related genes, inhibited tumor cell proliferation, promoted tumor cellapoptosis in a dose-dependent manner and restrained the growth of colon neoplasm. The effects of a high dose of Tsoong on colon cancer cells were similar to those of oxaliplatin. Our results may ultimately help in the development of diagnostic and therapeutic strategies to control this devastating disease. Therefore, Tsoong may be a promising Chinese herbal compound for development for use in cancer therapy.

Emodin inhibits TGF-β2 by activating the FOXD3/miR‑199a axis in ovarian cancer cells in vitro

Ovarian cancer is a highly metastatic malignancy and a leading cause of cancer-related death in postmenopausal women. Emodin is a natural anthraquinone isolated from several traditional Chinese medicines including Rhubarb and Polygonum cuspidatum. Recently, emodin was demonstrated to reduce the growth of human ovarian carcinoma cells. However, the mechanism remains unclear. In the present study, we identified that transforming growth factor (TGF)-β2 was significantly affected by emodin treatment in A2780 cells using microarray analysis. MicroRNA (miR)-199a was predicted as a potential miRNA targeting TGF-β2 by in silico prediction using TargetScan. The mRNA and protein levels of TGF-β2 were both significantly reduced by miR-199a. Spearman's correlation analysis revealed a significant correlation between the expression level of miR-199a and TGF-β2 in human ovarian cancer specimens. Silencing of miR-199a with miR-199a inhibitor significantly restored the reduction in TGF-β2 expression induced by emodin. Additionally, cell viability and colony formation of A2780 cells were markedly inhibited by emodin treatment, which was mediated by miR-199a. We analyzed the primary mature miR-199a-1 and miR-199a-2 transcripts in A2780 cells treated with emodin or dimethyl sulfoxide (DMSO) and found that only pri-miR-199a-1 was regulated by emodin. A conserved binding site of Forkhead box D3 (FOXD3) was identified within pri-miR-199a-1. We further revealed that miR-199a expression was significantly regulated by FOXD3. Taken together, the present study demonstrated that emodin may directly promote FOXD3 expression and sequentially activates miR-199a, which in turn suppresses the expression of TGF-β2 to reduce cell viability and colony formation of A2780 cells.

Aloesin Suppresses Cell Growth and Metastasis in Ovarian Cancer SKOV3 Cells through the Inhibition of the MAPK Signaling Pathway

Aloesin is an active constituent of the herb aloe vera and plays a crucial role in anti-inflammatory activity, ultraviolet protection, and antibacterium. We investigated the role and possible mechanisms of aloesin in the cell growth and metastasis of ovarian cancer. It was found that aloesin inhibited cell viability and cell clonality in a dose-dependent manner. It arrests the cell cycle at the S-phase and induced apoptosis in SKOV3 cells. In an in vivo experiment, it was observed that aloesin inhibited tumor growth. Moreover, it inhibited migration and invasion of cancer in SKOV3 cells. Interestingly, members from the mitogen-activated protein kinase (MAPK) signaling family became less phosphorylated as the aloesin dose increased. This suggests that aloesin exerts its anticancer effect through the MAPK signaling pathway. Our data also highlights the possibility of using aloesin as a novel therapeutic drug for ovarian cancer treatment.

Effect of aloe‑emodin on the proliferation and apoptosis of human synovial MH7A cells; a comparison with methotrexate

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovial hyperplasia. Methotrexate (MTX), an antifolate derivative, is used for the treatment of RA, as it exerts antiproliferative efftects on lymphocytes and synovial cells. Aloe‑emodin (AE) is a primary component of anthraquinones in Aloe vera and exerts antiproliferative and apoptotic effects on various tumor cells. In the present study, the effect of AE on the proliferation and apoptosis of MH7A human RA synovial cells was examined. In addition, the effect of AE was compared with that of the established RA therapeutic MTX. MH7A cells were incubated with 5, 10, 20 or 40 µM AE, or 0.01, 0.05, 0.1 or 1 µM MTX, for 24, 48 or 72 h. Subsequently, total cell numbers were assessed using trypan blue staining and Cell Counting kit‑8. Furthermore, MH7A cells incubated with AE or MTX for 48 h were evaluated for apoptosis following Annexin V/propidium iodide (PI) staining, and for cell cycle distribution following PI staining. The results indicated that ≥10 µM AE and ≥0.05 µM MTX effectively decreased the numbers of viable MH7A cells. In addition, 40 µM AE and 1 µM MTX induced apoptosis in MH7A cells. Cell cycle analysis revealed that ≥20 µM AE induced G2/M phase arrest, whereas ≥0.1 µM MTX induced S phase arrest. These observations suggested that AE treatment inhibited the growth of MH7A cells by arresting the cell cycle at a different checkpoint compared with MTX treatment. Thus, AE may be a potential therapeutic agent for the treatment of RA, and may be complimentary to MTX, based on its antiproliferative effect on synovial cells.

Aloe-emodin suppresses esophageal cancer cell TE1 proliferation by inhibiting AKT and ERK phosphorylation

Aberrant AKT and extracellular signal-regulated kinase (ERK) activation is often observed in various human cancers. Both AKT and ERK are important in the phosphoinositide 3-kinase/AKT and mitogen-activated protein kinase kinase/ERK signaling pathways, which play vital roles in cell proliferation, differentiation and survival. Compounds that are able to block these pathways have therefore a promising use in cancer treatment and prevention. The present study revealed that AKT and ERK are activated in esophageal cancer TE1 cells. Aloe-emodin, an anthraquinone present in aloe latex, can suppress TE1 cell proliferation and anchor-independent cell growth. Aloe-emodin can also reduce the number of TE1 cells in S phase. Protein analysis indicated that aloe-emodin inhibits the phosphorylation of AKT and ERK in a dose-dependent manner. Overall, the present data indicate that aloe-emodin can suppress TE1 cell growth by inhibiting AKT and ERK phosphorylation, and suggest its clinical use for cancer therapy.

Effects of dietary components on cancer of the digestive system

Cancer is the second leading cause of death in developed countries and poor diet and physical inactivity are major risk factors in cancer-related deaths. Therefore, interventions to reduce levels of smoking, improve diet, and increase physical activity must become much higher priorities in the general population's health and health care systems. The consumption of fruit and vegetables exerts a preventive effect towards cancer and in recent years natural dietary agents have attracted great attention in the scientific community and among the general public. Foods, such as tomatoes, olive oil, broccoli, garlic, onions, berries, soy bean, honey, tea, aloe vera, grapes, rosemary, basil, chili peppers, carrots, pomegranate, and curcuma contain active components that can influence the initiation and the progression of carcinogenesis, acting on pathways implied in cell proliferation, apoptosis and metastasis. The present review illustrates the main foods and their active components, including their antioxidant, cytotoxic, and pro-apoptotic properties, with a particular focus on the evidence related to cancers of the digestive system.

Effects of Aloe-emodin and Emodin on Proliferation of the MKN45 Human Gastric Cancer Cell Line

Aloe-emodin (1, 8-dihydroxy-3-hydroxyl-methylanthraquinone; AE) and emodin (1,3,8-trihydroxy-6- methylanthraquinone; EM) are anthraquinone derivatives that have been detected in some medical plants and share similar anthraquinone structures. AE and EM have been shown to exhibit anticancer activities in various cancer cell lines; however, the inhibitory effects of these derivatives on the growth of cancer cells were previously reported to be different. Gastric cancer is the second most common cause of cancer cell death worldwide. In the present study, we examined the inhibitory effects of 0.05 mM AE and 0.05 mM EM on the proliferation of the MKN45 human gastric cancer cell line. The proliferation of MKN45 cells was significantly inhibited in AE- and EM-treated groups 24 h and 48 h after treatment. Furthermore, the inhibitory effects of EM were stronger than those of AE. The cell cycle of MKN45 cells were arrested in G0/G1 phase or G0/G1 and G2/M phases by AE and EM, respectively. However, an analysis of intracellular polyamine levels and DNA fragmentation revealed that the mechanisms underlying cell death following cell arrest induced by AE and EM differed.

Aloe vera: Potential candidate in health management via modulation of biological activities

Treatment based on natural products is rapidly increasing worldwide due to the affordability and fewer side effects of such treatment. Various plants and the products derived from them are commonly used in primary health treatment, and they play a pivotal role in the treatment of diseases via modulation of biochemical and molecular pathways. Aloe vera, a succulent species, produces gel and latex, plays a therapeutic role in health management through antioxidant, antitumor, and anti-inflammatory activities, and also offers a suitable alternative approach for the treatment of various types of diseases. In this review, we summarize the possible mechanism of action and the therapeutic implications of Aloe vera in health maintenance based on its modulation of various biological activities.

Anti-tumor effect of emodin on gynecological cancer cells

PURPOSE

Although an anti-tumor effect of emodin has been reported before, its effect on human gynecological cancer cells has so far not been studied. Here, we assessed the effect of emodin on cervical cancer-derived (Hela), choriocarcinoma-derived (JAR) and ovarian cancer-derived (HO-8910) cells, and investigated the possible underlying molecular and cellular mechanisms.

METHODS AND RESULTS

The respective cells were treated with 0, 5, 10 or 15 μM emodin for 72 h. Subsequently, MTT and Transwell in vitro migration assays revealed that emodin significantly decreased the viability and invasive capacity of the gynecological cancer-derived cells tested. We found that emodin induced apoptosis and significantly decreased mitochondrial membrane potential and ATP release in these cells. We also found that emodin may exert its apoptotic effects via regulating the activity of caspase-9 and the expression of cleaved-caspase-3. Moreover, we found that emodin induced a cell cycle arrest at the G0/G1 phase, possibly through down-regulating the key cell cycle regulators Cyclin D and Cyclin E. Interestingly, emodin also led to autophagic cell death, as revealed by increased MAP LC3 expression, a marker of the autophagosome, and decreased expression of the autophagy regulators Beclin-1 and Atg12-Atg5. Finally, we found that the protein levels of both VEGF and VEGFR-2 were significantly decreased in emodin-treated cells, suggesting an anti-angiogenic effect of emodin on gynecological cancer-derived cells.

CONCLUSIONS

Our results suggest that emodin exhibits an anti-tumor effect on gynecological cancer-derived cells, possibly through multiple mechanisms including the induction of apoptosis and autophagy, the arrest of the cell cycle, and the inhibition of angiogenesis. Our findings may provide a basis for the design of potential emodin-based strategies for the treatment of gynecological tumors.

Inhibitory effects of low-dose aloe-emodin on the development of colorectal tumors in min mice

Aloe-emodin (AE), a natural anthraquinone compound, has been reported to exhibit anticancer activity in various cancer cell lines and anti-inflammatory effects in murine macrophages. In the present study, we investigated the cancer chemopreventive effects of AE in an Apc-deficient Min mouse model. In the first experiment, male Min mice were fed a basal diet or diets containing 5 ppm AE and 10 ppm AE for 12 weeks. The dietary administration of 5 ppm AE significantly reduced the number of colorectal tumors. In a second experiment, we investigated the effects of AE on colitis-related colon carcinogenesis in Min mouse treated with dextran sodium sulfate (DSS). Female Min mice were administered 1% DSS in their drinking water for 7 days. AE was given to mice in their diet at a dose of 5 or 50 ppm for 5 weeks. Feeding with AE significantly reduced the number of colorectal tumors. When proliferation of cells in normal-appearing colonic mucosa was assessed by monoclonal anti-rat Ki-67 antibody (MIB-5) immunohistochemistry in experiments 1 and 2, the AE treatment significantly decreased the mean MIB-5-labeling index. These results suggest that the dietary administration of low-dose AE may have chemopreventive effects against development of colorectal tumors in Min mice, possibly in part by reducing cell proliferation in colorectal mucosa.

Expression profile of genes modulated by Aloe emodin in human U87 glioblastoma cells

Glioblastoma, the most aggressive and malignant form of glioma, appears to be resistant to various chemotherapeutic agents. Hence, approaches have been intensively investigated to targeti specific molecular pathways involved in glioblastoma development and progression. Aloe emodin is believed to modulate the expression of several genes in cancer cells. We aimed to understand the molecular mechanisms underlying the therapeutic effect of Aloe emodin on gene expression profiles in the human U87 glioblastoma cell line utilizing microarray technology. The gene expression analysis revealed that a total of 8,226 gene alterations out of 28,869 genes were detected after treatment with 58.6 μg/ml for 24 hours. Out of this total, 34 genes demonstrated statistically significant change (p<0.05) ranging from 1.07 to 1.87 fold. The results revealed that 22 genes were up-regulated and 12 genes were down-regulated in response to Aloe emodin treatment. These genes were then grouped into several clusters based on their biological functions, revealing induction of expression of genes involved in apoptosis (programmed cell death) and tissue remodelling in U87 cells (p<0.01). Several genes with significant changes of the expression level e.g. SHARPIN, BCAP31, FIS1, RAC1 and TGM2 from the apoptotic cluster were confirmed by quantitative real-time PCR (qRT-PCR). These results could serve as guidance for further studies in order to discover molecular targets for the cancer therapy based on Aloe emodin treatment.

Inflammation-induced tumorigenesis in mouse colon is caspase-6 independent

Caspases play an important role in maintaining tissue homeostasis. Active Caspase-6 (Casp6) is considered a novel therapeutic target against Alzheimer disease (AD) since it is present in AD pathological brain lesions, associated with age-dependent cognitive decline, and causes age-dependent cognitive impairment in the mouse brain. However, active Casp6 is highly expressed and activated in normal human colon epithelial cells raising concerns that inhibiting Casp6 in AD may promote colon carcinogenesis. Furthermore, others have reported rare mutations of Casp6 in human colorectal cancers and an effect of Casp6 on apoptosis and metastasis of colon cancer cell lines. Here, we investigated the role of Casp6 in inflammation-associated azoxymethane/dextran sulfate sodium (AOM/DSS) colon cancer in Casp6-overexpressing and -deficient mice. In wild-type mice, AOM/DSS-induced tumors had significantly higher Casp6 mRNA, protein and activity levels compared to normal adjacent colon tissues. Increased human Casp6 or absence of Casp6 expression in mice colon epithelial cells did not change colonic tumor multiplicity, burden or distribution. Nevertheless, the incidence of hyperplasia was slightly reduced in human Casp6-overexpressing colons and increased in Casp6 null colons. Overexpression of Casp6 did not affect the grade of the tumors while all tumors in heterozygous or homozygous Casp6 null colons were high grade compared to only 50% high grade in wild-type mice. Casp6 levels did not alter cellular proliferation and apoptosis. These results suggest that Casp6 is unlikely to be involved in colitis-associated tumors.

Potential antineoplastic effects of Aloe-emodin: a comprehensive review

Aloe-emodin (AE), a bioactive anthraquinone derived from both Aloe vera and Rheum officinale, has recently been demonstrated to have various pharmacological activities. With the widespread popularity of natural products, such as antineoplastic drugs, AE has attracted much attention due to its remarkable antineoplastic activity on multiple tumor cells involving multi-channel mechanisms, including the disruption of cell cycle, induction of apoptosis, anti-metastasis, antiangiogenic, and strengthening of immune function. Experimental data have revealed AE as a potentially potent anti-cancer candidate. Despite this, the pharmaceutical application of AE is still in a fledging period as most research has concentrated on the elucidation of the molecular mechanism of action of existing treatments, rather than the development of novel formulations. Therefore, the present review summarizes the potential toxicity, molecular mechanism, pharmacokinetic characteristics, and pharmaceutical development of AE as an antineoplastic agent. This is based on its physicochemical properties, in an attempt to encourage further research on AE as a potential anti-cancer agent.

Chinese medicines induce cell death: the molecular and cellular mechanisms for cancer therapy

Chinese medicines have long history in treating cancer. With the growing scientific evidence of biomedical researches and clinical trials in cancer therapy, they are increasingly accepted as a complementary and alternative treatment. One of the mechanisms is to induce cancer cell death. Aim. To comprehensively review the publications concerning cancer cell death induced by Chinese medicines in recent years and provide insights on anticancer drug discovery from Chinese medicines. Materials and Methods. Chinese medicines (including Chinese medicinal herbs, animal parts, and minerals) were used in the study. The key words including “cancer”, “cell death”, “apoptosis”, “autophagy,” “necrosis,” and “Chinese medicine” were used in retrieval of related information from PubMed and other databases. Results. The cell death induced by Chinese medicines is described as apoptotic, autophagic, or necrotic cell death and other types with an emphasis on their mechanisms of anticancer action. The relationship among different types of cell death induced by Chinese medicines is critically reviewed and discussed. Conclusions. This review summarizes that CMs treatment could induce multiple pathways leading to cancer cell death, in which apoptosis is the dominant type. To apply these preclinical researches to clinic application will be a key issue in the future.

Ethnobotanical survey of usage of fresh medicinal plants in Singapore

ETHNOPHARMACOLOGICAL RELEVANCE

The use of medicinal plants in human health has been documented since ancient times and they provide a useful source of new therapeutics. In Singapore, despite the accessibility to modern healthcare, there still exist pockets of the population who choose to use locally grown fresh medicinal plants for health promotion and even therapeutic purposes. However to date, there is no published report of first-hand account of their usage in Singapore. As land is scarce and rapidly used for re-development, such important knowledge may be lost if not properly documented in time. This work safeguards the local folk knowledge, and provides information on common and scarcely reported fresh medicinal plants. The objective of this study is to gather information regarding the usage of fresh medicinal plants in Singapore through face-to-face interviews.

MATERIALS AND METHODS

Information on demographic data and plant-use methods were collated via face-to-face interviews of 200 fresh medicinal plant users who have used fresh medicinal plants in the last five years. The survey protocol was approved by the National University of Singapore Institutional Review Board and informed consent was obtained from every participant.

RESULTS

A total of 414 plants represented by 104 plant species from 44 families were reportedly used by the 200 participants. The five most commonly used plants were Clinacanthus nutans (34 users), Strobilanthes crispus (31 users), Pereskia bleo (25 users), Aloe vera (18 users) and Zingiber officinale (16 users). Leaves were the most commonly used plant part while preparing a decoction was the most common method of preparation. The majority of interviewees used plants for general health purposes and to treat diseases related to the respiratory system and cancer.

CONCLUSIONS

Our survey has successfully documented the rich wealth of traditional usage and knowledge on 414 fresh medicinal plants grown in Singapore through face-to-face interviews with 200 users. This study will serve as a useful resource for identifying promising plants for future drug discovery efforts. Scientific evaluations of these medicinal plants are warranted and should be carried out.

Emodin suppresses Wnt signaling in human colorectal cancer cells SW480 and SW620

Wnt signaling is involved in the regulation of cell proliferation, differentiation and apoptosis. Its aberrant activation is a key event in the pathogenesis and progression of human colorectal cancers. Dietary phytochemicals are gaining importance as chemotherapeutic agents owing to their potential to prevent, delay or reverse oncogenesis. Here we demonstrate that emodin (1,3,8-trihydroxy-6-methylanthraquinone), an anthraquinone present in the roots and bark of several medicinal plants, down regulates Wnt signaling pathway in human colorectal cancer cells (SW480 and SW620) by down regulating TCF/LEF transcriptional activity. Emodin significantly down regulated the expression of key players of Wnt signaling (β-catenin and TCF7L2) and also that of its various downstream targets (cyclin D1, c-Myc, snail, vimentin, MMP-2 and MMP-9). Two novel targets of emodin׳s action were discovered namely Wnt co-activator p300 (down regulated) and repressor HBP1 (up regulated). Morphological changes induced by emodin suggest mesenchymal to epithelial transition accompanied by the increase in E-cadherin expression in human colorectal cancer cells but a differentiation marker (alkaline phosphatase) was activated only in SW620 cells (metastatic origin) and not in SW480 cells (primary tumor-derived). Moreover, our data indicate that reactive oxygen species plays a key role in emodin-mediated down regulation of Wnt signaling as emodin-mediated inhibition of migration and induction of growth arrest were partially rescued by the reactive oxygen species scavenger ascorbic acid. Effects of emodin shown in this study may provide important insights for the use of this anthraquinone as a potential complementary and integrated medicine for the treatment of human colorectal cancer.

Crude extract of Rheum palmatum L induced cell death in LS1034 human colon cancer cells acts through the caspase-dependent and -independent pathways

Crude extract of Rheum palmatum L (CERP) has been used to treat different diseases in the Chinese population for decades. In this study, we investigated the effects of CERP on LS1034 human colorectal cancer cells in vitro and also examined possible mechanisms of cell death. Flow cytometric assays were used to measure the percentage of viable cells, cell cycle distribution including the sub-G1 phase (apoptosis), the activities of caspase-8, -9, and -3, reactive oxygen species (ROS) and Ca(2+) levels, and mitochondrial membrane potential (ΔΨm). DNA damage, nuclei condensation, protein expression, and translocation were examined by Comet assay, 4'-6-diamidino-2-phenylindole (DAPI) staining, Western blotting, and confocal laser system microscope, respectively. CERP induced apoptosis as seen by DNA fragmentation and DAPI staining in a concentration- and time-dependent manner in cancer cells. CERP was associated with an increase in the Bax/Bcl-2 protein ratio and CERP promoted the activities of caspase-8, -9, and -3. Both ROS and Ca(2+) levels were increased by CERP but the compound decreased levels of ΔΨm in LS1034 cells. Laser confocal microscope also confirmed that CERP promoted the expressions of AIF, Endo G, cytochrome c, and GADD153 to induce apoptosis through mitochondrial-dependent pathway.

Anticancer and antimicrobial activities of some antioxidant-rich cameroonian medicinal plants

Traditional remedies have a long-standing history in Cameroon and continue to provide useful and applicable tools for treating ailments. Here, the anticancer, antimicrobial and antioxidant activities of ten antioxidant-rich Cameroonian medicinal plants and of some of their isolated compounds are evaluated.The plant extracts were prepared by maceration in organic solvents. Fractionation of plant extract was performed by column chromatography and the structures of isolated compounds (emodin, 3-geranyloxyemodin, 2-geranylemodin) were confirmed spectroscopically. The antioxidant activity (AOA) was determined using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) bleaching method, the trolox equivalent antioxidant capacity (TEAC), and the hemoglobin ascorbate peroxidase activity inhibition (HAPX) assays. The anticancer activity was evaluated against A431 squamous epidermal carcinoma, WM35 melanoma, A2780 ovary carcinoma and cisplatin-resistant A2780cis cells, using a direct colorimetric assay. The total phenolic content in the extracts was determined spectrophotometrically by the Folin–Ciocalteu method. Rumex abyssinicus showed the best AOA among the three assays employed. The AOA of emodin was significantly higher than that of 3-geranyloxyemodin and 2-geranylemodin for both TEAC and HAPX methods. The lowest IC₅₀ values (i.e., highest cytotoxicity) were found for the extracts of Vismia laurentii, Psorospermum febrifugum, Pentadesma butyracea and Ficus asperifolia. The Ficus asperifolia and Psorospermum febrifugum extracts are selective against A2780cis ovary cells, a cell line which is resistant to the standard anticancer drug cisplatin. Emodin is more toxic compared to the whole extract, 3-geranyloxyemodin and 2-geranylemodin. Its selectivity against the platinum-resistant A2780cis cell line is highest. All of the extracts display antimicrobial activity, in some cases comparable to that of gentamycin.