The role of targeting kinase activity by natural products in cancer chemoprevention and chemotherapy (Review)

An Integrated Molecular Networking and Docking Approach to Characterize the Metabolome of Helichrysum splendidum and Its Pharmaceutical Potentials

South Africa is rich in diverse medicinal plants, and it is reported to have over 35% of the global Helichrysum species, many of which are utilized in traditional medicine. Various phytochemical studies have offered valuable insights into the chemistry of Helichrysum plants, hinting at bioactive components that define the medicinal properties of the plant. However, there are still knowledge gaps regarding the size and diversity of the Helichrysum chemical space. As such, continuous efforts are needed to comprehensively characterize the phytochemistry of Helichrysum, which will subsequently contribute to the discovery and exploration of Helichrysum-derived natural products for drug discovery. Thus, reported herein is a computational metabolomics work to comprehensively characterize the metabolic landscape of the medicinal herb Helichrysum splendidum, which is less studied. Metabolites were methanol-extracted and analyzed on a liquid chromatography-tandem mass spectrometry (LC-MS/MS) system. Spectral data were mined using molecular networking (MN) strategies. The results revealed that the metabolic map of H. splendidum is chemically diverse, with chemical superclasses that include organic polymers, benzenoids, lipid and lipid-like molecules, alkaloids, and derivatives, phenylpropanoids and polyketides. These results point to a vastly rich chemistry with potential bioactivities, and the latter was demonstrated through computationally assessing the binding of selected metabolites with CDK-2 and CCNB1 anti-cancer targets. Molecular docking results showed that flavonoids (luteolin, dihydroquercetin, and isorhamnetin) and terpenoids (tiliroside and silybin) interact strongly with the CDK-2 and CCNB1 targets. Thus, this work suggests that these flavonoid and terpenoid compounds from H. splendidum are potentially anti-cancer agents through their ability to interact with these proteins involved in cancer pathways and progression. As such, these actionable insights are a necessary step for further exploration and translational studies for H. splendidum-derived compounds for drug discovery.

Natural Products in Precision Oncology: Plant-Based Small Molecule Inhibitors of Protein Kinases for Cancer Chemoprevention

Striking progress is being made in cancer treatment by using small molecule inhibitors of specific protein kinases that are products of genes recognized as drivers for a specific type of cancer. However, the cost of newly developed drugs is high, and these pharmaceuticals are neither affordable nor accessible in most parts of the world. Accordingly, this narrative review aims to probe how these recent successes in cancer treatment can be reverse-engineered into affordable and accessible approaches for the global community. This challenge is addressed through the lens of cancer chemoprevention, defined as using pharmacological agents of natural or synthetic origin to impede, arrest, or reverse carcinogenesis at any stage in the disease process. In this regard, prevention refers to reducing cancer-related deaths. Recognizing the clinical successes and limitations of protein kinase inhibitor treatment strategies, the disciplines of pharmacognosy and chemotaxonomy are juxtaposed with current efforts to exploit the cancer kinome to describe a conceptual framework for developing a natural product-based approach for precision oncology.

UR-144, synthetic cannabinoid receptor agonist, induced cardiomyoblast toxicity mechanism comprises cytoplasmic Ca2+ and DAPK1 related autophagy and necrosis

UR-144, a cannabinoid receptor agonist, is widely used alone or in combination with other synthetic cannabinoids (SCs) all over the world. At overdose, cardiovascular symptoms have been reported and the underlying molecular mechanisms of these adverse effects are not known. It is highly important to clarify the toxic effects of UR-144 for the treatment of poisoning. In the present study, the molecular mechanism of cytotoxic effects of UR-144 is evaluated on a cardiomyoblastic cell line using WST-1 and LDH assays. Apoptosis/necrosis, autophagy, and ROS (reactive oxygen species) levels were determined using flow cytometry. Cytoplasmic Ca²⁺ levels were measured by using a fluorogenic calcium-binding dye. Released and cytoplasmic troponin T levels, a specific marker of cardiotoxicity, were examined with western blot. For the evaluation of the role of DAPK1, on UR-144-induced cell death, DAPK1 activity and DAPK1 protein level were investigated. Its cytotoxic effects increased in a dose-dependent manner for WST-1 and LDH assays, while membrane damage, one of the signs of necrotic cell death, was more remarkable than damage to mitochondria. Cytoplasmic Ca²⁺ levels rose after high-dose UR-144 treatment and inhibition of DAPK1 activity ameliorated UR-144-induced cytotoxicity. Released troponin T significantly increased at a dose of 200 µM. ROS and total antioxidant capacity of cells were both reduced following high dose UR-144 treatment. The results indicated that UR-144-induced autophagic and necrotic cell death might be a consequence of elevated cytoplasmic Ca²⁺ levels and DAPK1 activation. However, in vivo/clinical studies are needed to identify molecular mechanisms of cardiotoxic effects of UR-144.

Exploring the recent trends in perturbing the cellular signaling pathways in cancer by natural products

Cancer is commonly thought to be the product of irregular cell division. According to the World Health Organization (WHO), cancer is the major cause of death globally. Nature offers an abundant supply of bioactive compounds with high therapeutic efficacy. Anticancer effects have been studied in a variety of phytochemicals found in nature. When Food and Drug Administration (FDA)-approved anticancer drugs are combined with natural compounds, the effectiveness improves. Several agents have already progressed to clinical trials based on these promising results of natural compounds against various cancer forms. Natural compounds prevent cancer cell proliferation, development, and metastasis by inducing cell cycle arrest, activating intrinsic and extrinsic apoptosis pathways, generating reactive oxygen species (ROS), and down-regulating activated signaling pathways. These natural chemicals are known to affect numerous important cellular signaling pathways, such as NF-B, MAPK, Wnt, Notch, Akt, p53, AR, ER, and many others, to cause cell death signals and induce apoptosis in pre-cancerous or cancer cells without harming normal cells. As a result, non-toxic “natural drugs” taken from nature’s bounty could be effective for the prevention of tumor progression and/or therapy of human malignancies, either alone or in combination with conventional treatments. Natural compounds have also been shown in preclinical studies to improve the sensitivity of resistant cancers to currently available chemotherapy agents. To summarize, preclinical and clinical findings against cancer indicate that natural-sourced compounds have promising anticancer efficacy. The vital purpose of these studies is to target cellular signaling pathways in cancer by natural compounds.

Regulation of DAPK1 by Natural Products: An Important Target in Treatment of Stroke

Stroke is a sudden neurological disorder that occurs due to impaired blood flow to an area of the brain. Stroke can be caused by the blockage or rupture of a blood vessel in the brain, called ischemic stroke and hemorrhagic stroke, respectively. Stroke is more common in men than women. Atrial fibrillation, hypertension, kidney disease, high cholesterol and lipids, genetic predisposition, inactivity, poor nutrition, diabetes mellitus, family history and smoking are factors that increase the risk of stroke. Restoring blood flow by repositioning blocked arteries using thrombolytic agents or endovascular therapy are the most effective treatments for stroke. However, restoring circulation after thrombolysis can cause fatal edema or intracranial hemorrhage, and worsen brain damage in a process known as ischemia-reperfusion injury. Therefore, there is a pressing need to find and develop more effective treatments for stroke. In the past, the first choice of treatment was based on natural compounds. Natural compounds are able to reduce the symptoms and reduce various diseases including stroke that attract the attention of the pharmaceutical industry. Nowadays, as a result of the numerous studies carried out in the field of herbal medicine, many useful and valuable effects of plants have been identified. The death-associated protein kinase (DAPK) family is one of the vital families of serine/threonine kinases involved in the regulation of some biological functions in human cells. DAPK1 is the most studied kinase within the DAPKs family as it is involved in neuronal and recovery processes. Dysregulation of DAPK1 in the brain is involved in the developing neurological diseases such as stroke. Natural products can function in a variety of ways, including reducing cerebral edema, reducing brain endothelial cell death, and inhibiting TNFα and interleukin-1β (IL-1β) through regulating the DAPK1 signal against stroke. Due to the role of DAPK1 in neurological disorders, the aim of this article was to investigate the role of DAPK1 in stroke and its modulation by natural compounds.

8-Formylophiopogonanone B induces ROS-mediated apoptosis in nasopharyngeal carcinoma CNE-1 cells

Cancer is one of the leading causes of death in the world. It is very important to find drugs with high efficiency, low toxicity, and low side effects for the treatment of cancer. Flavonoids and their derivatives with broad biological functions have been recognized as anti-tumor chemicals. 8-Formylophiopogonanone B (8-FOB), a naturally existed homoisoflavonoids with rarely known biological functions, needs pharmacological evaluation. In order to explore the possible anti-tumor action of 8-FOB, we used six types of tumor cells to evaluate in vitro effects of this agent on cell viability and tested the effects on clone formation ability, scratching wound-healing, and apoptosis. In an attempt to elucidate the mechanism of pharmacological action, we examined 8-FOB-induced intracellular oxidative stress and -disrupted mitochondrial function. Results suggested that 8-FOB could suppress tumor cell viability, inhibit cell migration and invasion, induce apoptosis, and elicit intracellular ROS production. Among these six types of tumor cells, the nasopharyngeal carcinoma CNE-1 cells were the most sensitive cancer cells to 8-FOB treatment. Intracellular ROS production played a pivotal role in the anti-tumor action of 8-FOB. Our present study is the first to document that 8-FOB has anti-tumor activity in vitro and increases intracellular ROS production, which might be responsible for its anti-tumor action. The anti-tumor pharmacological effect of 8-FOB is worthy of further investigation.

Targeting Drug Chemo-Resistance in Cancer Using Natural Products

Cancer is one of the leading causes of death globally. The development of drug resistance is the main contributor to cancer-related mortality. Cancer cells exploit multiple mechanisms to reduce the therapeutic effects of anticancer drugs, thereby causing chemotherapy failure. Natural products are accessible, inexpensive, and less toxic sources of chemotherapeutic agents. Additionally, they have multiple mechanisms of action to inhibit various targets involved in the development of drug resistance. In this review, we have summarized the basic research and clinical applications of natural products as possible inhibitors for drug resistance in cancer. The molecular targets and the mechanisms of action of each natural product are also explained. Diverse drug resistance biomarkers were sensitive to natural products. P-glycoprotein and breast cancer resistance protein can be targeted by a large number of natural products. On the other hand, protein kinase C and topoisomerases were less sensitive to most of the studied natural products. The studies discussed in this review will provide a solid ground for scientists to explore the possible use of natural products in combination anticancer therapies to overcome drug resistance by targeting multiple drug resistance mechanisms.

Aster ageratoides Turcz. extract attenuates Alzheimer's disease-associated cognitive deficits and vascular dementia-associated neuronal death

Dementia is the common neurodegenerative disorder affecting the elderly, with a progressive cognitive decline and memory loss. Since Alzheimer’s disease (AD) and vascular dementia (VD) share key pathologies including oxidative damage, oral supplement of phytochemical medicines, which are well-known for their antioxidant properties, can be a viable therapy for both types of dementia. In this study, the therapeutic potential of the Aster ageratoides extract (AAE), an oriental drug with multiple medicinal properties, was tested on experimental rat models of AD and VD. After confirming the in vitro attenuation of neuronal excitotoxicity by AAE, rats were orally administered with AAE for 7 days and subsequently tested under 2 different experimental paradigms: efficacy screening against #1 AD and #2 VD. For paradigm #1, the rats received intraperitoneal scopolamine and subsequently underwent 3 different behavior tests i.e., the Y-maze, novel object recognition, and passive avoidance tests. For paradigm #2, the rats were operated with the 2-vessel occlusion and hypovolemia (2VO/H) technique, and at postoperative day 7, their hippocampal neuronal viability and the neuroinflammatory changes were quantified. The results showed that the scopolamine-induced impairment of memory performance was significantly improved by AAE intake. Furthermore, while the 2VO/H operation induced marked hippocampal neuronal death and microglial activation, both these effects were significantly attenuated by AAE supplements. Some of the aforementioned effects of AAE intake were dose-dependent. These results provided evidence that AAE supplements can exert anti-AD and -VD efficacies and suggested that AAE might be used as an edible phytotherapeutic for the 2 major types of dementia.

Colonic Bacteria-Transformed Catechin Metabolite Response to Cytokine Production by Human Peripheral Blood Mononuclear Cells

Human gut microbes are a profitable tool for the modification of food compounds into biologically active metabolites. The biological properties of catechins have been extensively investigated. However, the bioavailability of catechin in human blood plasma is very low. This study aimed to determine the biotransformed catechin metabolites and their bioactive potentials for modulating the immune response of human peripheral blood mononuclear cells (PBMCs). Biotransformation of catechin was carried out using in-vitro gut microbial biotransformation method, the transformed metabolites were identified and confirmed by gas chromatography-mass spectrometry (GC–MS) and high-performance liquid chromatography-mass spectrometry (HPLC–MS). Present observations confirmed that the catechin was biotransformed into 11 metabolites upon microbial dehydroxylation and C ring cleavage. Further, immunomodulatory potential of catechin metabolites was analyzed in peripheral blood mononuclear cells (PBMCs). We found up-regulation of anti-inflammatory cytokine (IL-4, IL-10) and down-regulation of pro-inflammatory (IL-16, IL-12B) cytokine may be due to Th2 immune response. In conclusion, biotransformed catechin metabolites enhance anti-inflammatory cytokines which is beneficial for overcoming inflammatory disorders.

Sotetsuflavone Induces Autophagy in Non-Small Cell Lung Cancer Through Blocking PI3K/Akt/mTOR Signaling Pathway in Vivo and in Vitro

Non-small cell lung cancer (NSCLC) is a globally scaled disease with a high incidence and high associated mortality rate. Autophagy is one of the important physiological activities that helps to control cell survival, influences the dynamics of cell death, and which plays a crucial role in the pathophysiology of NSCLC. Sotetsuflavone is a naturally derived and occurring flavonoid, and previous studies have demonstrated that sotetsuflavone possesses potential anti-cancer activities. However, whether or not sotetsuflavone induces autophagy, as well as has effects and influences cell death in NSCLC cells remains unclear. Thus, in our study, we examined and elucidated the roles and underlying mechanisms of sotetsuflavone upon the dynamics of autophagy in NSCLC in vivo and in vitro. The results indicated that sotetsuflavone was able to inhibit proliferation, migration, and invasion of NSCLC cells. Mechanistically, sotetsuflavone was able to induce apoptosis by increasing the levels of expression of cytochrome C, cleaved-caspase 3, cleaved-caspase 9, and Bax, and contrastingly decreased levels of expression of Bcl-2. In addition, we also found that decreased levels of expression of cyclin D1 and CDK4 caused arrest of the G0/G1 phases of the cell cycle. Furthermore, we also found that sotetsuflavone could induce autophagy which in turn can play a cytoprotective effect on apoptosis in NSCLC. Sotetsuflavone-induced autophagy appeared related to the blocking of the PI3K/Akt/mTOR pathway. Our in vivo study demonstrated that sotetsuflavone significantly inhibited the growth of xenograft model inoculated A549 tumor with high a degree of safety. Taken together, these findings suggest that sotetsuflavone induces autophagy in NSCLC cells through its effects upon blocking of the PI3K/Akt/mTOR signaling pathways. Our study may provide a theoretical basis for future clinical applications of sotetsuflavone and its use as a chemotherapeutic agent for treatment of NSCLC.

Identification of Inhibitors Based on Molecular Docking: Thyroid Hormone Transmembrane Transporter MCT8 as a Target

AIMS

To identify natural inhibitors against MCT8 for Allan-Herndon-Dudley Syndrome.

BACKGROUND

Monocarboxylate Transporter 8 (MCT8) is a Thyroid Hormone (TH) transporter which is highly expressed in the liver and brain. Mutations in the MCT8 gene (SLC16A2) cause a syndrome of psychomotor retardation in humans, known as Allan-Herndon-Dudley syndrome (AHDS). Currently, no treatment is available for AHDS. Therefore, there is a need to discover new inhibitors of MCT8 for treating AHDS.

OBJECTIVE

Considering the importance of natural compounds in drug discovery, this study aimed to identify potential natural inhibitors against MCT8.

METHODS

As Protein-ligand interactions play a key role in structure based drug design, this study screened 24 natural kinase inhibitors and investigated their binding affinity against MCT8 by using molecular docking. The modelled 3D structure of MCT8 docked with 24 compounds using PyRX through Autodock Vina. Drug-likeness studies were made using Swiss ADME and Lipinski's rule of five was performed. Triac, desipramine and silychristin were used as the positive controls. Binding energies of the selected compounds were compared with that of positive controls.

RESULT

The results showed that emodin exhibited best binding energy of -8.6 kcal/mol followed by helenaquinol, cercosporamide and resveratrol. Moreover, it was observed that emodin and helenaquinol exhibit higher binding energy than the positive controls. Cercosporamide and resveratrol exhibited higher binding energy than triac and desipramine and showed the binding energy similar to silychristin.

CONCLUSION

This study reveals that these compounds could be promising candidates for further evaluation for AHDS prevention.

Trichothecin inhibits invasion and metastasis of colon carcinoma associating with SCD-1-mediated metabolite alteration

Lipid metabolic abnormalities have received intensified concerns and increased de novo synthesis of lipids is recognized as a common feature of many human cancers. Nevertheless, the role of lipid metabolism that confers aggressive properties on human cancers still remains to be revealed. Natural compounds represent an abundant pool of agents for the discovery of novel lead compounds. Trichothecin (TCN) is a sesquiterpenoid originating from an endophytic fungus of the herbal plant Maytenus hookeri Loes. Here, we assess the association of stearoyl-CoA desaturase 1 (SCD-1) over-expression with malignant progression of colorectal cancer (CRC). Based on this association, the effect of TCN on migration and invasion of colon carcinoma cells closely related to the inhibition of SCD-1 is evaluated. We further demonstrate that reduced production of unsaturated fatty acids (FAs) by blocking SCD-1 activity is beneficial for the anti-invasion effect of TCN. The aim of this study was to clarify the mechanistic connection between metabolite alterations induced by metabolic rewiring and the aggressive tumor phenotype and further develop novel pharmacological tools for the intervention of tumor invasion associated with SCD-1-mediated metabolite alterations.

DHRS2 mediates cell growth inhibition induced by Trichothecin in nasopharyngeal carcinoma

BACKGROUND

Cancer is fundamentally a deregulation of cell growth and proliferation. Cancer cells often have perturbed metabolism that leads to the alteration of metabolic intermediates. Dehydrogenase/reductase member 2 (DHRS2) belongs to short-chain alcohol dehydrogenase/reductase (SDR) superfamily, which is functionally involved in a number of intermediary metabolic processes and in the metabolism of lipid signaling molecules. DHRS2 displays closely association with the inhibition of cell proliferation, migration and quiescence in cancers.

METHODS

3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4- sulfophenyl)-2H-tetrazolium (MTS), 5-ethynyl-2'-deoxyuridine (EdU) and colony formation assays were applied to evaluate the proliferative ability of nasopharyngeal carcinoma (NPC) cells. We performed lipid metabolite profiling using gas chromatography coupled with mass spectrometry (GC/MS) to identify the proximal metabolite changes linked to DHRS2 overexpression. RNA sequencing technique combined with differentially expressed genes analysis was applied to identify the expression of genes responsible for the anti-tumor effect of trichothecin (TCN), a natural sesquiterpenoid compound isolated from an endophytic fungus.

RESULTS

Our current findings reveal that DHRS2 affects lipid metabolite profiling to induce cell cycle arrest and growth inhibition in NPC cells. Furthermore, we demonstrate that TCN is able to induce growth inhibition of NPC in vitro and in vivo by up-regulating DHRS2.

CONCLUSIONS

Our report suggests that activating DHRS2 to reprogram lipid homeostasis may be a target for the development of targeted therapies against NPC. Moreover, TCN could be exploited for therapeutic gain against NPC by targeting DHRS2 and it may also be developed as a tool to enhance understanding the biological function of DHRS2.

Lycorine inhibited the cell growth of non-small cell lung cancer by modulating the miR-186/CDK1 axis

AIMS

Lycorine is a kind of natural alkaloid with anti-cancer potential. It has been demonstrated that lycorine processes high activity and specificity against the progression of cancers. However, the underlying molecular mechanisms by which lycorine regulates the formation and development of non-small cell lung cancer (NSCLC) remain largely unknown.

MAIN METHODS

The effects of lycorine on the growth of NSCLC cells were determined by the cell counting kit-8 (CCK-8) assay, colony formation and flow cytometry analysis. RT-qPCR was performed to detect the expression of microRNA with lycorine treatment. The binding of miRNA and target genes was confirmed by luciferase reporter assay.

KEY FINDINGS

Lycorine significantly inhibited the proliferation and induced apoptosis of NSCLC cells. Mechanistically, lycorine up-regulated the expression of microRNA-186 in NSCLC cells. Depletion of miR-186 significantly reversed the suppressive effect of lycorine on the proliferation of NSCLC cells. Furthermore, the cyclin dependent kinase 1 (CDK1) was identified as one of the binding candidates of miR-186. Experimental analysis showed that miR-186 bound the 3'-untranslated region (3'-UTR) of CDK1 and suppressed the level of CDK1 in NSCLC cells. Consistently, exposure of lycorine significantly decreased the expression of CDK1. Restoration of CDK1 remarkably attenuated the inhibition of lycorine on the proliferation of NSCLC cells.

SIGNIFICANCE

Our results uncovered the novel molecular mechanism of lycorine in suppressing the progression of NSCLC partially via regulating the miR-186/CDK1 axis.

Kaempferol Attenuates ROS-Induced Hemolysis and the Molecular Mechanism of Its Induction of Apoptosis on Bladder Cancer

Bladder cancer has become the most common malignant urinary carcinoma. Studies have shown that significant antioxidant and bladder cancer-fighting properties of several plant-based diets like Psidium guajava, ginger and amomum, are associated with their high kaempferol content. In this paper, we evaluated the antioxidant and anticancer activities of kaempferol and its mechanism of induction to apoptosis on bladder cancer cells. Our findings demonstrated that kaempferol showed an obvious radical scavenging activity in erythrocytes damaged by oxygen. Kaempferol promoted antioxidant enzymes, inhibited ROS generation and lipid peroxidation and finally prevented the occurrence of hemolysis. Additionally, kaempferol exhibited a strong inhibitory effect on bladder cancer cells and high safety on normal bladder cells. At the molecular level, kaempferol suppressed EJ bladder cancer cell proliferation by inhibiting the function of phosphorylated AKT (p-AKT), CyclinD1, CDK4, Bid, Mcl-1 and Bcl-xL, and promoting p-BRCA1, p-ATM, p53, p21, p38, Bax and Bid expression, and finally triggering apoptosis and S phase arrest. We found that Kaempferol exhibited strong anti-oxidant activity on erythrocyte and inhibitory effects on the growth of cancerous bladder cells through inducing apoptosis and S phase arrest. These findings suggested that kaempferol might be regarded as a bioactive food ingredient to prevent oxidative damage and treat bladder cancer.

Flavonoids inhibit cell proliferation and induce apoptosis and autophagy through downregulation of PI3Kγ mediated PI3K/AKT/mTOR/p70S6K/ULK signaling pathway in human breast cancer cells

Anticancer activities of flavonoids derived from Tephroseris kirilowii (Turcz.) Holub. were evaluated in human cancer cells. We isolated and identified, for the first time, eight flavonoids from T. kirilowii and found that three of them (IH: isorhamnetin, GN: genkwanin, and Aca: acacetin) inhibited cell proliferation in a variety of human cancer cell lines. These active flavonoids caused cell cycle arrest at G2/M phase and induced apoptosis and autophagy in human breast cancer cells. Molecular docking revealed that these flavonoids dock in the ATP binding pocket of PI3Kγ. Importantly, treatment with these flavonoids decreased the levels of PI3Kγ-p110, phospho-PI3K, phospho-AKT, phospho-mTOR, phospho-p70S6K, and phospho-ULK. Pretreatment with PI3Kγ specific inhibitor AS605240 potentiated flavonoids-mediated inactivation of AKT, mTOR, p70S6K, ULK, and apoptosis. Taken together, these findings represent a novel mechanism by which downregulation of PI3Kγ-p110 and consequent interruption of PI3K/AKT/mTOR/p70S6K/ULK signaling pathway might play a critical functional role in these flavonoids-induced cell cycle arrest at G2/M phase, apoptosis, and autophagy. Our studies provide novel insights into the anticancer activities of selected flavonoids and their potential uses in anticancer therapy.

The antitumor activity screening of chemical constituents from Camellia nitidissima Chi

Chemotherapy is the preferred and most common treatment for cancer in clinical practice. An increasing number of researchers all over the world are focusing on natural medicines to find new antitumor drugs, and several reports have shown that Camellia nitidissima (C. nitidissima) Chi could reduce blood-lipid, decrease blood pressure, resist oxidation, prevent carcinogenesis and inhibit tumors. Therefore, the pharmacodynamics of the chemical constituents in C. nitidissima need to be investigated further. In the present study, 16 chemical constituents were isolated from the leaves of C. nitidissima, of which 6 compounds are reported to be found in this plant for the first time. Furthermore, all these phytochemicals were screened for antitumor activity on 4 common cancer cell lines, while compound 3, one oleanane-type triterpene, exhibited the most potential antitumor effects. Interestingly, to our knowledge, this was the first report that compound 3 inhibits cancer cells. Compound 3 inhibited EGFR-mutant lung cancer cell line, NCI-H1975 via apoptosis effect, with an IC50 of 13.37±2.05 µM at 48 h. Based on the data, compound 3 showed potential for antitumor drug development, suggesting the scientific basis for the antitumor activity of C. nitidissima.

Assessment of genetic integrity, splenic phagocytosis and cell death potential of (Z)-4-((1,5-dimethyl-3-oxo-2-phenyl-2,3dihydro-1H-pyrazol-4-yl) amino)-4-oxobut-2-enoic acid and its effect when combined with commercial chemotherapeutics

The increased incidence of cancer and its high treatment costs have encouraged the search for new compounds to be used in adjuvant therapies for this disease. This study discloses the synthesis of (Z)-4-((1,5-dimethyl-3-oxo-2-phenyl-2,3dihydro-1H-pyrazol-4-yl) amino)-4-oxobut-2-enoic acid (IR-01) and evaluates not only the action of this compound on genetic integrity, increase in splenic phagocytosis and induction of cell death but also its effects in combination with the commercial chemotherapeutic agents doxorubicin, cisplatin and cyclophosphamide. IR-01 was designed and synthesized based on two multifunctionalyzed structural fragments: 4-aminoantipyrine, an active dipyrone metabolite, described as an antioxidant and anti-inflammatory agent; and the pharmacophore fragment 1,4-dioxo-2-butenyl, a cytotoxic agent. The results indicated that IR-01 is an effective chemoprotector because it can prevent clastogenic and/or aneugenic damage, has good potential to prevent genomic damage, can increase splenic phagocytosis and lymphocyte frequency and induces cell death. However, its use as an adjuvant in combination with chemotherapy is discouraged since IR-01 interferes in the effectiveness of the tested chemotherapeutic agents. This is a pioneer study as it demonstrates the chemopreventive effects of IR-01, which may be associated with the higher antioxidant activity of the precursor structure of 4-aminoantipyrine over the effects of the 1,4-dioxo-2-butenyl fragment.

Inhibitory effect of hyperoside isolated from Zanthoxylum bungeanum leaves on SW620 human colorectal cancer cells via induction of the p53 signaling pathway and apoptosis

The present study aimed to demonstrate the antiproliferative effect of hyperoside from Zanthoxylum bungeanum leaves (HZL) and explain the underlying molecular mechanisms in the SW620 human colorectal cancer cell line. The cytotoxic effects of HZL were determined using a3‑(4,5‑dimethylthiazol‑2‑yl)2,5‑diphenyltetrazolium bromide assay. Apoptosis and cell cycle were detected using flow cytometry. Reactive oxygen species (ROS) levels and mitochondrial membrane potential (∆Ψm) were assessed using 2',7'‑dichlorofluorescin diacetate and 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolyl carbocyanine iodide fluorescence spectrophotometry, respectively. Western blot analysis was used to quantify the expression levels of apoptosis‑associated proteins. Reverse transcription‑quantitative polymerase chain reaction analysis was used to determine the mRNA expression of glutathione peroxidase (GSH‑Px) and catalase (CAT). HZL had a marked anti‑proliferative effect on the SW620 human colorectal cancer cells by inducing cell cycle G2/M phase arrest and apoptosis, which was associated with an increase in the expression of p53 and p21. Further mechanistic investigations revealed that the induction of apoptosis was associated with increased generation of ROS, reduced ∆Ψm, and upregulation of B‑cell lymphoma 2‑associated X protein, cytochrome c, caspase‑9, apoptotic protease activating factor 1 and caspase‑3. The antitumor potency of HZL was also attributed to inhibition of the mRNA expression levels of GSH‑Px and CAT. These data indicated that HZL may be involved in the pro‑apoptotic signaling of SW620 human colorectal cancer cells via induction of the caspase‑dependent apoptosis and p53 signaling pathways.

Induction of p53-Independent Apoptosis and G1 Cell Cycle Arrest by Fucoidan in HCT116 Human Colorectal Carcinoma Cells

It is well known that fucoidan, a natural sulfated polysaccharide present in various brown algae, mediates anticancer effects through the induction of cell cycle arrest and apoptosis. Nevertheless, the role of tumor suppressor p53 in the mechanism action of fucoidan remains unclear. Here, we investigated the anticancer effect of fucoidan on two p53 isogenic HCT116 (p53+/+ and p53-/-) cell lines. Our results showed that inhibition of cell viability, induction of apoptosis and DNA damage by treatment with fucoidan were similar in two cell lines. Flow cytometric analysis revealed that fucoidan resulted in G1 arrest in the cell cycle progression, which correlated with the inhibition of phosphorylation of retinoblastoma protein (pRB) and concomitant association of pRB with the transcription factor E2Fs. Furthermore, treatment with fucoidan obviously upregulated the expression of cyclin-dependent kinase (CDK) inhibitors, such as p21WAF1/CIP1 and p27KIP1, which was paralleled by an enhanced binding with CDK2 and CDK4. These events also commonly occurred in both cell lines, suggesting that fucoidan triggered G1 arrest and apoptosis in HCT116 cells by a p53-independent mechanism. Thus, given that most tumors exhibit functional p53 inactivation, fucoidan could be a possible therapeutic option for cancer treatment regardless of the p53 status.

Grifolin induces apoptosis and promotes cell cycle arrest in the A2780 human ovarian cancer cell line via inactivation of the ERK1/2 and Akt pathways

Grifolin, a secondary metabolic product isolated from the mushroom Albatrellus confluence, has been demonstrated to possess antitumor activities in a variety of malignant cells. However, the signaling pathways and the molecular mechanisms underlying the anticancer effects of the agent in human ovarian cancer remain to be elucidated. The aim of the present study was to examine the effect of grifolin treatment on the human ovarian cancer cell line, A2780. MTT and flow cytometry analysis were used to analyze the viability of A2780 cells following treatment with grifolin. Western blotting was used analyze the expression of apoptosis-associated and cell cycle arrest-associated proteins. The results of MTT assays and flow cytometry analysis revealed that grifolin suppressed cell viability, induced apoptosis and triggered cell cycle arrest. Western blotting revealed that grifolin treatment resulted in inactivation of protein kinase B (Akt) and extracellular signal-related kinase 1/2 (ERK1/2), accompanied by upregulation of Bcl-2 associated X, apoptosis regulator, cleaved-caspase-3 and cleaved-poly (ADP-ribose) polymerase, and downregulation of B cell lymphoma-2, cyclin dependent kinase 4 and cyclinD1. The results of the present study indicated that grifolin had significant anti-cancer effects on the human ovarian cancer A2780 cells, which occurred via the Akt and ERK1/2 signaling pathways to at least a certain extent. These results demonstrate the therapeutic potential of grifolin as a treatment for ovarian cancer.

Reduction-oxidation pathways involved in cancer development: a systematic review of literature reviews

Oxidative stress results from an imbalance of the reactive oxygen species/reactive nitrogen species (ROS/RNS) production and the oxidants defense system. Extensive research during the last decades has revealed that oxidative stress can mediate cancer initiation and development by leading not only to molecular damage but also to a disruption of reduction-oxidation (redox) signaling. In order to provide a global overview of the redox signaling pathways, which play a role in cancer formation, we conducted a systematic literature search in PubMed and ISI Web of Science and identified 185 relevant reviews published in the last 10 years. The 20 most frequently described pathways were selected to be presented in this systematic review and could be categorized into 3 groups: Intracellular ROS/RNS generating organelles and enzymes, signal transduction cascades kinases/phosphatases and transcription factors. Intracellular ROS/RNS generation organelles are mitochondria, endoplasmic reticulum and peroxisomes. Enzymes, including NOX, COX, LOX and NOS, are the most prominent enzymes generating ROS/RNS. ROS/RNS act as redox messengers of transmembrane receptors and trigger the activation or inhibition of signal transduction kinases/phosphatases, such as the family members of protein tyrosine kinases and protein tyrosine phosphatases. Furthermore, these reactions activate downstream signaling pathways including protein kinase of the MAPK cascade, PI3K and PKC. The kinases and phosphatases regulate the phosphorylation status of transcription factors including APE1/Ref-1, HIF-1α, AP-1, Nrf2, NF-κB, p53, FOXO, STAT, and β-catenin. Finally, we briefly discuss cancer prevention and treatment opportunities, which address redox pathways and further research needs.

Natural Compounds As Modulators of Non-apoptotic Cell Death in Cancer Cells

Cell death is an innate capability of cells to be removed from microenvironment, if and when they are damaged by multiple stresses. Cell death is often regulated by multiple molecular pathways and mechanism, including apoptosis, autophagy, and necroptosis. The molecular network underlying these processes is often intertwined and one pathway can dynamically shift to another one acquiring certain protein components, in particular upon treatment with various drugs. The strategy to treat human cancer ultimately relies on the ability of anticancer therapeutics to induce tumor-specific cell death, while leaving normal adjacent cells undamaged. However, tumor cells often develop the resistance to the drug-induced cell death, thus representing a great challenge for the anticancer approaches. Numerous compounds originated from the natural sources and biopharmaceutical industries are applied today in clinics showing advantageous results. However, some exhibit serious toxic side effects. Thus, novel effective therapeutic approaches in treating cancers are continued to be developed. Natural compounds with anticancer activity have gained a great interest among researchers and clinicians alike since they have shown more favorable safety and efficacy then the synthetic marketed drugs. Numerous studies in vitro and in vivo have found that several natural compounds display promising anticancer potentials. This review underlines certain information regarding the role of natural compounds from plants, microorganisms and sea life forms, which are able to induce non-apoptotic cell death in tumor cells, namely autophagy and necroptosis.

Grifolin inhibits tumor cells adhesion and migration via suppressing interplay between PGC1α and Fra-1 / LSF- MMP2 / CD44 axes

Grifolin, a farnesyl phenolic compound isolated from the fresh fruiting bodies of the mushroom Albatrellus confluens, exhibits effective antitumor bioactivity in previous study of our group and other lab. In this study, we observed that grifolin inhibited tumor cells adhesion and migration. Moreover, grifolin reduced reactive oxygen species (ROS) production and caused cellular ATP depletion in high-metastatic tumor cells. PGC1α (Peroxisome proliferator-activated receptor γ, coactivator 1α) encodes a transcriptional co-activator involved in mitochondrial biogenesis and respiration and play a critical role in the maintenance of energy homeostasis. Interestingly, grifolin suppressed the mRNA as well as protein level of PGC1α. We further identified that MMP2 and CD44 expressions were PGC1α inducible. PGC1α can bind with metastatic-associated transcription factors: Fra-1 and LSF and the protein-protein interaction was attenuated by grifolin treatment. Overall, these findings suggest that grifolin decreased ROS generation and intracellular ATP to suppress tumor cell adhesion/migration via impeding the interplay between PGC1α and Fra-1 /LSF-MMP2/CD44 axes. Grifolin may develop as a promising lead compound for antitumor therapies by targeting energy metabolism regulator PGC1α signaling.