Anticancer Activity of Novel Daphnane Diterpenoids from Daphne genkwa through Cell-Cycle Arrest and Suppression of Akt/STAT/Src Signalings in Human Lung Cancer Cells

Daphne genkwa: Ethnopharmacology, phytochemistry and pharmacology of an important traditional Chinese medicine

Daphne genkwa, as a traditional medicine, is widely distributed in China, Korea and Vietnam. In China, the dried flower buds of this plant are named "Yuanhua". It has the ability to effectively promote urination, eliminate phlegm and alleviate cough, eliminate parasites and cure of scabies, with a broad spectrum of pharmacological effects and considerable clinical efficacy. This paper provides a summary and classification of the main chemical constituents of D. genkwa based on a review of relevant domestic and foreign literature. It also outlines the current research status of traditional clinical usage, pharmacological effects, and toxicity of D. genkwa. The aim is to provide a theoretical basis for further study of D. genkwa and its potential new clinical applications.

Bioactive daphnane diterpenes from the flower buds of Daphne genkwa (Thymelaeaceae)

Four diterpenes of the daphnane type were isolated from a methanol extract of the flower buds of Daphne genkwa, the two of them were new structures named genkwadanes J (1) and K (2). Their structures were determined based on analysis of their 1D- and 2D-NMR, HRESIMS and ECD calculations. Among the isolates, the cytotoxicity was assessed via the MTT method using the K562, MCF-7 and HeLa cancer cell lines, the positive control was taxol. Compounds 1 and 3 exhibited appreciable cytotoxic activity against the K562 cancer cell line with IC50 values between 6.58 and 5.33 μM. Compounds 2 and 4 showed noteworthy inhibitory effects against the MCF-7 cell line with IC50 values of 3.25 and 2.56 μM, respectively. All compounds showed weak cytotoxicities to the Hela cell line with IC50 values in the range of 20.19-55.23 μM.

LC-ESI QToF MS Non-Targeted Screening of Latex Extracts of Euphorbia seguieriana ssp. seguieriana Necker and Euphorbia cyparissias and Determination of Their Potential Anticancer Activity

Euphorbia seguieriana ssp. seguieriana Necker (ES) and Euphorbia cyparissias (EC) with a habitat in the Deliblato Sands were the subject of this examination. The latexes of these so far insufficiently investigated species of the Euphorbia genus are used in traditional medicine for the treatment of wounds and warts on the skin. To determine their chemical composition, non-targeted screening of the latexes' chloroform extracts was performed using liquid chromatography coupled with quadrupole time-of-flight mass spectrometry employing an electrospray ionization source (LC-ESI QTOF MS). The analysis of the obtained results showed that the latexes of ES and EC represent rich sources of diterpenes, tentatively identified as jatrophanes, ingenanes, tiglianes, myrsinanes, premyrsinanes, and others. Examination of the anticancer activity of the ES and EC latex extracts showed that both extracts significantly inhibited the growth of the non-small cell lung carcinoma NCI-H460 and glioblastoma U87 cell lines as well as of their corresponding multi-drug resistant (MDR) cell lines, NCI-H460/R and U87-TxR. The obtained results also revealed that the ES and EC extracts inhibited the function of P-glycoprotein (P-gp) in MDR cancer cells, whose overexpression is one of the main mechanisms underlying MDR.

Assessment of antioxidant and antiparkinsonian potential of a new diterpene isolated from Croton argyrophylloides

Oxidative stress is related to health problems including neurological and neurodegenerativedisturbs, such as Parkinson's disease. Natural compounds are reported as source of antioxidant molecules. Therefore, this study aimed to analyze the antioxidant and neuroprotective potential of a new diterpene isolated from C. argyrophylloides (MP-1). Male Wistar rats (250-300 g) were used to evaluate MP-1 antiparkinsonian potential through neurodegenerative model induced by the neurotoxin 6-hydroxydopamine (21 μg). On the 14th day, animals were submitted to behavioral tests and on the 15th day, brain areas were dissected to neurochemical analyzes. MP-1 demonstrated a high antioxidant capacity in vitro and decreased the parkinsonian effects, such as behavioral changes, motor alterations, and body weight loss. MP-1 was also able to control the upregulated levels of nitrosative stress and lipid peroxidation. These findings suggest MP-1 as a diterpene with high antioxidant capacity which might be used to development of new approach against Parkinson's disease.

Phytochemical analysis of Daphne pontica L. stems with their pro-apoptotic properties against DU-145 and LNCaP prostate cancer cells

BACKGROUND

Daphne pontica is an endemic plant grown wild in the North part of Iran, with anticancer activities.

OBJECTIVES

This study aims to analyze the phytochemistry and screen the cytotoxic activity of new bioactive compounds against a panel of cancer cells, in addition to proapototic properties against prostate cancer cells.

METHOD

Purification procedure was done using repeated column chromatographies by MPLC and HPLC systems. The structures were elucidated by the NMR and exact mass spectroscopy, stereochemistry by NOESY, and absolute configuration by electronic circular dichroism (ECD) spectra. Cytotoxicity was done against DU 145, LNCaP, HeLa, MCF-7, and MDA-MB 231 cells by standard MTT assay. An annexin V/PI assay was performed to measure the type of death following treatment with these compounds for 48 h, followed by the caspase-3 activity test.

RESULTS

In this study, one new dilignan named lignopontin A (9), in addition to 13 known compounds including two phenolic acids (3, 5), one flavanone (6), one bis flavonoid (1), one cumarin glycoside (2), one mono (4) and two dicumarins (10, 11), two lignans (7, 8), and three daphnane diterpenoids (12-14) were isolated for the first time from D. pontica stems. Complete spectral data of compound 12, named as 6,7α-epoxy-5β-hydroxy-9,13,14-ortho-(4,2E)-pentadeca-2,4-diene-1-yl)-resiniferonol, and compound 14, named as 6,7α-epoxy-5β-hydroxy-9,3,14-ortho-(2,4E)-pentadeca-2,4-di-1-yl)-resiniferonol-12β-yl-acetate are reported for the first time. In the MTT assay of newly described compounds against a panel of cancer cells, compounds 9, 12, and 14 possessed moderate to potent cytotoxicity against prostate, breast, and cervical cancer cells in a dose-dependent manner. Flow cytometry analysis against prostate cancer cells indicated that the cytotoxicity of compounds 12 and 14 was due to their ability to induce apoptosis. In the case of compound 9, in Du 145 cells, cell death was mainly through apoptosis. In contrast, LNCaP cells showed both apoptosis and necrotic cell death, predominated by necrosis at the higher concentrations. Caspase-3 activity confirmed apoptosis observed in these compounds through the caspase pathway in prostate cancer cells.

CONCLUSION

D. pontica is a new source of dimeric phenolic compounds, including bisflavonoids, phenylpropanoid-cumarin adduct, and dilignans, as well as daphnane diterpenoids with resiniferonol core with long-chain orthoester moieties. In cytotoxicity screening, compounds 9, 12, and 14 inhibited the growth of DU-145 and LNCaP cells in a dose-dependent manner with IC₅₀ varied from 0.9 - 27.3 and 25.2 - 87.4 μM, respectively. Among them, 9 exhibited selective growth inhibition against DU 145 treated cells. LNCaP cells demonstrated the highest sensitivity to treatment with compound 12.

Yuanhuacin and Related Anti-Inflammatory and Anticancer Daphnane Diterpenes from Genkwa Flos—An Overview

The dried flower buds of the plant Daphne genkwa Sieb. et Zucc. have been largely used in traditional Chinese medicine for the treatment of inflammatory diseases. Numerous diterpenoids have been isolated from the Genkwa Flos (yuanhua in Chinese), including a series of daphnane-type diterpene designated as yuanhuacin (YC, often improperly designated as yuanhuacine) and analogues with a patronymic name. The series includes ten daphnane-type diterpenes: yuanhuacin, yuanhuadin (YD), yuanhuafin (YF), yuanhuagin (YG), yuanhuahin (YH), yuanhuajin (YJ), yuanhualin (YL), yuanhuamin (YM), yuanhuapin (YP), and yuanhuatin (YT). They are distinct from the rare flavonoid yuanhuanin. The series comprises several anticancer agents, such as the lead compound YC, which has revealed potent activity in vitro and in vivo against models of lung and breast cancers. The main signaling pathways implicated in the antitumor effects have been delineated. Protein kinase C is a key factor of activity for YC, but in general the molecular targets at the origin of the activity of these compounds remain little defined. Promising anticancer effects have been reported with analogues YD and YT, whereas compounds YF and YP are considered more toxic. The pharmacological activity of each compound is presented, as well as the properties of Genkwa Flos extracts. The potential toxic effects associated with the use of these compounds are also underlined.

Advances in plant-derived natural products for antitumor immunotherapy

In recent years, immunotherapy has emerged as a novel antitumor strategy in addition to traditional surgery, radiotherapy and chemotherapy. It uniquely focuses on immune cells and immunomodulators in the tumor microenvironment and helps eliminate tumors at the root by rebuilding the immune system. Despite remarkable breakthroughs, cancer immunotherapy still faces many challenges: lack of predictable and prognostic biomarkers, adverse side effects, acquired treatment resistance, high costs, etc. Therefore, more efficacious and efficient, safer and cheaper antitumor immunomodulatory drugs have become an urgent requirement. For decades, plant-derived natural products obtained from land and sea have provided the most important source for the development of antitumor drugs. Currently, more attention is being paid to the discovery of potential cancer immunotherapy modulators from plant-derived natural products, such as polysaccharides, phenols, terpenoids, quinones and alkaloids. Some of these agents have outstanding advantages of multitargeting and low side effects and low cost compared to conventional immunotherapeutic agents. We intend to summarize the progress of comprehensive research on these plant-derived natural products and their derivatives and discuss their possible mechanisms in regulating the immune system and their efficacy as monotherapies or in combination with regular chemotherapeutic agents.

Phytochemistry and Pharmacological Activities of the Diterpenoids from the Genus Daphne

There are abundant natural diterpenoids in the plants of the genus Daphne from the Thymelaeaceae family, featuring a 5/7/6-tricyclic ring system and usually with an orthoester group. So far, a total of 135 diterpenoids has been isolated from the species of the genus Daphne, which could be further classified into three main types according to the substitution pattern of ring A and oxygen-containing functions at ring B. A variety of studies have demonstrated that these compounds exert a wide range of bioactivities both in vitro and in vivo including anticancer, anti-inflammatory, anti-HIV, antifertility, neurotrophic, and cholesterol-lowering effects, which is reviewed herein. Meanwhile, the fascinating structure-activity relationship is also concluded in this review in the hope of providing an easy access to available information for the synthesis and optimization of efficient drugs.

Chemical characterization, computational analysis and biological views on Daphne gnidioides Jaub. & Spach extracts: Can a new raw material be provided for biopharmaceutical applications?

The scientific world tends to turn to natural products such as medicinal and aromatic plants because of the inadequacy of commercially available synthetic drugs as antibiotics or anticancer, and their adverse effects on healthy tissues. One of these plants is Daphne gnidioides Jaub. & Spach, which belongs to the Thymelaeaceae family, and there is no data in the literature on its biological activity. This study is aimed to elucidate the chemical profiles and in vitro anticancer, antibacterial and DNA protection and enzyme inhibitory properties of methanol extracts of root, stem, and leaf of D. gnidioides Jaub. & Spach. Polyphenolic components of the extracts were characterized by HPLC-MS/MS. The highest phenolic content was detected in the leaf extract (TIPC = 43.5 ± 0.5 mg/g DE), followed by stem (TIPC = 27.3 ± 0.7 mg/g DE) and root (TIPC = 18.3 ± 0.2 mg/g DE) extracts. Vicenin-2 and 3-O-p-coumaroyl-5-O-caffeoylquinic acid were the main identified compounds in leaf and both root and stem extracts, respectively. The extracts did not show any protective effect on DNA against experimental Fenton's reagent. The minimum inhibitory concentration and the minimum bactericidal concentration values for the root and leaf extracts against tested bacterial strains ranged from 31.25 to 500 μg/mL. After 48 h interaction of the cancer cell lines with the extracts, only the stem extract had significant cytotoxicity on HeLa cells (IC50 = 86.16 μg/mL). No remarkable activity of the extracts, which was tested against MDA-MB-231, was detected (IC50 > 1000 μg/mL). These data showed that D. gnidioides Jaub. & Spach stem extract inhibited the survival of HeLa cells in a time-dependent manner. After the treatment of IC50 concentration of stem extract with HeLa cells, an increase in LC3-II autophagic gene expression was detected. Also, the extracts exhibited significant tyrosinase inhibitory effects which were confirmed by molecular docking. To sum up, the tested extracts could be used as a starting point for the development of new multifunctional drugs.

The genus Daphne: A review of its traditional uses, phytochemistry and pharmacology

The genus Daphne belongs to the Thymeleaceae family and contains over 90 species that are distributed in Asia, Europe and parts of North Africa. The species of the genus Daphne are used in the traditional medicine of China, Tibet, Korea, and the Middle East for the treatment of various conditions. A broad range of studies has shown the significant biological potential of these species as sources of biologically and pharmacologically active compounds. Daphne species are a source of several classes of valuable phytochemicals such as coumarins, flavonoids, lignans, steroids and different classes of terpenes. The phytochemical diversity of this genus is demonstrated by over 350 secondary metabolites isolated from various species. The genus possesses a broad spectrum of biological activities including antibacterial, antifungal, antioxidant, analgesic, anti-inflammatory, cytotoxic, antiviral, abortive and haemostatic effects. A variety of bioactive secondary metabolites found in this genus may have potential use in pharmaceutical, cosmetic and food industries. Thus, species belonging to the genus Daphne can be considered an important source both for the treatment of various disorders, due to the presence of a plethora of bioactive constituents with potent bioactivities, and as possible leads in the discovery and synthesis of new medications.

A Review on Daphnane-Type Diterpenoids and Their Bioactive Studies

Natural daphnane diterpenoids, mainly distributed in plants of the Thymelaeaceae and Euphorbiaceae families, usually include a 5/7/6-tricyclic ring system with poly-hydroxyl groups located at C-3, C-4, C-5, C-9, C-13, C-14, or C-20, while some special types have a characteristic orthoester motif triaxially connectedat C-9, C-13, and C-14. The daphnane-type diterpenoids can be classified into five types: 6-epoxy daphnane diterpenoids, resiniferonoids, genkwanines, 1-alkyldaphnanes and rediocides, based on the oxygen-containing functions at rings B and C, as well as the substitution pattern of ring A. Up to now, nearly 200 daphnane-type diterpenoids have been isolated and elucidated from the Thymelaeaceae and Euphorbiaceae families. In-vitro and in-vivo experiments of these compounds have shown that they possess a wide range of biological activities, including anti-HIV, anti-cancer, anti-leukemic, neurotrophic, pesticidal and cytotoxic effects. A comprehensive account of the structural diversity is given in this review, along with the cytotoxic activities of daphnane-type diterpenoids, up to April 2019.

AXL degradation in combination with EGFR-TKI can delay and overcome acquired resistance in human non-small cell lung cancer cells

Acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) has been a major obstacle in the treatment of non-small cell lung cancer (NSCLC) patients. AXL has been reported to mediate EGFR-TKIs. Recently, third generation EGFR-TKI osimertinib has been approved and yet its acquired resistance mechanism is not clearly understood. We found that AXL is involved in both gefitinib and osimertinib resistance using in vitro and in vivo model. In addition, AXL overexpression was correlated with extended protein degradation rate. We demonstrate targeting AXL degradation is an alternative route to restore EGFR-TKIs sensitivity. We confirmed that the combination effect of YD, an AXL degrader, and EGFR-TKIs can delay or overcome EGFR-TKIs-driven resistance in EGFR-mutant NSCLC cells, xenograft tumors, and patient-derived xenograft (PDX) models. Therefore, combination of EGFR-TKI and AXL degrader is a potentially effective treatment strategy for overcoming and delaying acquired resistance in NSCLC.

Incompatibility assessment of Genkwa Flos and Glycyrrhizae Radix et Rhizoma with biochemical, histopathological and metabonomic approach

ETHNOPHARMACOLOGICAL RELEVANCE

As recorded in traditional Chinese medicine (TCM) theory, Genkwa Flos (YH) and Glycyrrhizae Radix et Rhizoma (GC) compose one herbal pair of the so-called "eighteen incompatible medicaments", which indicate pairs of herbs that are mutually incompatible and that theoretically should not be applied simultaneously. However, the theory has been called into question due to a lack of evidence.

AIMS OF STUDY

In this study, the incompatibility of YH and GC was investigated based on an assessment of the toxic effects of their combination by traditional safety methods and a modern metabonomic approach.

MATERIALS AND METHODS

Sprague-Dawley rats were used to evaluate the subacute toxicity of YH and YH-GC. The serum, urine, and several tissues were collected for biochemical analysis, histopathological examination, and metabonomic analysis.

RESULTS

Rats exposed to a dose of 1.0 g/kg YH (3 times of the Chinese Pharmacopoeia maximum dose) exhibited toxicity of the heart, liver, kidney and testes, and rats exposed to a YH-GC combination (1.0 g/kg YH + 1.0 g/kg GC) exhibited similar hepatotoxicity, which aggravated renal and reproductive toxicity. Following this, a metabonomic study tentatively identified 14 potential biomarkers in the YH group and 10 potential biomarkers in the YH-GC group, and metabolic pathways were then constructed. YH disturbed the pathways of glycerophospholipid metabolism, primary bile acid biosynthesis, and sphingolipid metabolism, while YH-GC combination induced disruptions in phenylalanine, tyrosine and tryptophan biosynthesis, tyrosine metabolism, and glycerophospholipid metabolism.

CONCLUSION

The toxicities of YH and YH-GC combination above the Chinese Pharmacopoeia dose were obvious but different. Metabonomics combined with biochemical and histopathological methods can be applied to elucidate the toxicity mechanism of the YH-GC combination that caused liver, kidney and reproductive injuries in rats.

Design, synthesis and anticancer activity of fluorocyclopentenyl-purines and - pyrimidines

Based on the potent anticancer activity of 6'-fluorocyclopentenyl-cytosine 2b in phase IIa clinical trials for the treatment of gemcitabine-resistant pancreatic cancer, we carried out a systematic structure-activity relationship study of 6'-fluorocyclopentenyl-pyrimidines 3a-i and -purines 3j-o to discover novel anticancer agents. We also synthesized the phosphoramidate prodrug 3p of adenine derivative 1b to determine if the anticancer activity depended on the inhibition of DNA and/or RNA polymerase in cancer cells and/or on the inhibition of S-adenosylhomocysteine (SAH) hydrolase. All of the synthesized pyrimidine nucleosides exhibited much less potent anticancer activity in vitro than the cytosine derivative 2b, acting as RNA and/or DNA polymerase inhibitor, indicating that they could not be efficiently converted to their triphosphates for anticancer activity. Among all the synthesized purine nucleosides, adenine derivative 1b and N⁶-methyladenine derivative 3k showed potent anticancer activity, showing equipotent inhibitory activity as the positive control, neplanocin A (1a) or Ara-C. However, the phosphoramidate prodrug 3p showed less anticancer activity than 1b, indicating that it did not act as a RNA and/or DNA polymerase inhibitor like 2b. This result also demonstrates that the anticancer activity of 1b largely depends on the inhibition of histone methyltransferase, resulting from strong inhibition of SAH hydrolase. The deamination of the N⁶-amino group, the addition of the bulky alkyl group at the N⁶-amino group, or the introduction of the amino group at the C2 position almost abolished the anticancer activity.

Screening for selective anticancer activity of plants from Grazalema Natural Park, Spain

Since plants are an important source of anticancer drugs, we have carried out a random screening for selective anticancer activity of 57 extracts from 45 plants collected in Grazalema Natural Park, an area in the South of Spain of high plant diversity and endemism. Using lung cancer cells (A549) and lung non-malignant cells (MRC-5), we found that several extracts were more cytotoxic and selective against the cancer cells than the standard anticancer agent cisplatin. Five active extracts were further tested in cancer and normal cell lines from other tissues, including three skin cell lines with increasing degree of malignancy. An extract from the leaves of Daphne laureola L. (Thymelaeaceae) showed a striking potency and selectivity on lung cancer cells and leukemia cells; the IC₅₀ values against these cancer cells were approximately 10,000-fold lower than against the normal cells. Daphnane-type diterpene orthoesters may be responsible for this highly selective anticancer activity.

Shikonin causes apoptosis by disrupting intracellular calcium homeostasis and mitochondrial function in human hepatoma cells

Shikonin is known to suppress proliferation and induce apoptosis in a variety of cancer cell lines. In the present study, SMMC-7721 human hepatocellular carcinoma cells were treated with shikonin (1, 2 or 4 µM) for 12–48 h. Cell morphological alterations and DNA damage were determined. Furthermore, changes in cell cycle, mitochondrial transmembrane potential, calcium homeostasis and levels of reactive oxygen species were measured. Shikonin-treated SMMC-7721 cells exhibited morphological changes and DNA damage. Shikonin inhibited cell proliferation causing cell cycle arrest at the G₀/G₁ phase and induced apoptosis in a dose- and time-dependent manner. Shikonin-induced apoptosis was associated with activation of caspases-3, −8 and −9, elevated levels of intracellular Ca²⁺ and reactive oxygen species, reduced mitochondrial membrane potential and enhanced efflux of Ca²⁺ and K⁺. Gene expression B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax), p53 and caspase-3 was up-regulated, whereas Bcl-2 expression was downregulated. Shikonin caused apoptosis by inhibiting cell cycle progression, disrupting Ca²⁺ homeostasis, inducing oxidative stress and triggering mitochondrial dysfunction. Activation of caspases-3, −8 and −9, K⁺ efflux, and regulation of Bax, Bcl-2, p53 and caspase-3 expression are involved in the process. These results provide in-depth insight into the mechanisms of action of shikonin in the treatment of cancer.

Elucidating high-dimensional cancer hallmark annotation via enriched ontology

MOTIVATION

Cancer hallmark annotation is a promising technique that could discover novel knowledge about cancer from the biomedical literature. The automated annotation of cancer hallmarks could reveal relevant cancer transformation processes in the literature or extract the articles that correspond to the cancer hallmark of interest. It acts as a complementary approach that can retrieve knowledge from massive text information, advancing numerous focused studies in cancer research. Nonetheless, the high-dimensional nature of cancer hallmark annotation imposes a unique challenge.

RESULTS

To address the curse of dimensionality, we compared multiple cancer hallmark annotation methods on 1580 PubMed abstracts. Based on the insights, a novel approach, UDT-RF, which makes use of ontological features is proposed. It expands the feature space via the Medical Subject Headings (MeSH) ontology graph and utilizes novel feature selections for elucidating the high-dimensional cancer hallmark annotation space. To demonstrate its effectiveness, state-of-the-art methods are compared and evaluated by a multitude of performance metrics, revealing the full performance spectrum on the full set of cancer hallmarks. Several case studies are conducted, demonstrating how the proposed approach could reveal novel insights into cancers.

AVAILABILITY

https://github.com/cskyan/chmannot.

Plants from The Genus Daphne: A Review of its Traditional Uses, Phytochemistry, Biological and Pharmacological Activity

Plants have an important role in maintaining people’s health and improving the quality of human life. They are an important component of people’s diet, but they are also used in other spheres of human life as a therapeutic resources, ingredients of cosmetic products, paints and others. The Daphne genus belongs to family Thymeleaceae which includes 44 families with approximately 500 herbal species. The plant species of the genus Daphne are used in the traditional medicine in China and tropical part of Africa for the treatment of various conditions. Previous studies showed significant biological potential of these species as a source of pharmacologically active compounds. This indicates that this genus possess a broad spectrum of biological activity including antimicrobial, antioxidant, analgesic, anti-inflammatory, cytotoxic, anti-ulcerogenic, abortive, hypocholesterolemic and hemostatic effects. Additionally, Daphne plants are the source of valuable bioactive phytochemicals such as coumarins, flavonoids, lignans, steroids and different classes of terpenes. Different parts of the Daphne plants contain specific bioactive metabolites and can represent a source of new, natural, pharmacologically active compounds, which may potentially be used in pharmaceutical, cosmetic and food industries.

Cryptotanshinone inhibits lung tumor growth by increasing CD4+ T cell cytotoxicity through activation of the JAK2/STAT4 pathway

Cryptotanshinone is one of the fat-soluble phenanthrene quinone components. In vitro studies have shown that tanshinone compounds can inhibit the proliferation of various tumor cells and affect cell cycle distribution. The aim of the present study was to better understand the effect of cryptotanshinone on the inhibition of small cell lung cancer by cytotoxic cluster of differentiation (CD)4⁺ T cells through activation of the Janus kinase 2/signal transducer and activator of transcription 4 (JAK2/STAT4) pathway. The Cell Counting kit-8 assay and the lactate dehydrogenase assay were used to analyze the cell proliferation of H446 and CD4⁺ T cells, and the cell cytotoxicity of CD4⁺ and CD8⁺ T cells, respectively. JAK2 and STAT4 protein expression was measured by western blot analysis. Cryptotanshinone effectively inhibited the tumor growth of the H446 cells and the cell proliferation of the CD4⁺ T cells. Treatment with cryptotanshinone increased the cytotoxicity of the CD4⁺ T cells, but could not affect the cytotoxicity of the CD8⁺ T cells. Meanwhile, cryptotanshinone induced phosphorylated (p)-JAK2 and p-STAT4 protein expression in the CD4⁺ T cells. These results suggest that cryptotanshinone inhibits the cell growth of lung tumors by increasing CD4⁺ T cell toxicity through activation of the JAK2/STAT4 pathway.

Akt regulation of Aven contributes to the sensitivity of cancer cells to chemotherapeutic agents

In the present study, it was demonstrated that the protein level of the apoptosis inhibitor Aven is regulated by the Akt signaling pathway, evidenced by the observation that Aven levels were significantly increased in MCF7 constitutively active (CA)‑Akt cells and significantly inhibited following treatment with LY294002. This increase in Aven appears not to be mediated by transcriptional regulation and protein stabilization. However, the level of Aven was inversely correlated with the level of cathepsin D, which is a protease responsible for generating the C‑terminal of Aven, ΔN‑Aven, indicating that the level of Aven appears to be regulated by cathepsin D activity. It has previously been reported that ΔN‑Aven is the active form of Aven, which functions as an anti‑apoptotic molecule. Notably, low levels of ΔN‑Aven were detected in MCF7 CA‑Akt cells, which were more sensitive to anticancer drugs. Taken together, the current results suggest that the expression of Aven is regulated by the Akt signaling pathway through cathepsin D activity, which contributes to the sensitivity of cancer cells to chemotherapeutic agents.

Genkwadaphnin induces IFN-γ via PKD1/NF-κB/STAT1 dependent pathway in NK-92 cells

The flower buds of Daphne genkwa Sieb. et Zucc. have been used as a traditional Chinese medicine although their functional mechanisms have not been discovered yet. We have studied the potential effects of the plant extracts on natural killer (NK) cell activation, and isolated an active fraction. Genkwadaphnin (GD-1) displayed a potent efficacy to induce IFN-γ transcription in NK cells with concentration- and time-dependent manners. GD-1 treatment triggered the phosphorylation of PKD1, a member of PKC family, MEK and ERK, resulting in IKK activation to induce IκB degradation, and the nuclear localization of p65, an NF-κB subunit, which regulates IFN-γ transcription. GD-1 effect on IFN-γ production was blocked by the addition of Rottlerin, a PKC inhibitor, CID 755673, a PKD inhibitor, or Bay11-7082, an IKKα inhibitor. The nuclear localization of p65 was also inhibited by the kinase inhibitors. Secreted IFN-γ activates STAT1 phosphorylation as autocrine-loops to sustain its secretion. GD-1 induced the phosphorylation of STAT1 probably through the increase of IFN-γ. STAT1 inhibitor also abrogated the sustained IFN-γ secretion. These results suggest that GD-1 is involved in the activation of PKD1 and/or ERK pathway, which activate NK-κB triggering IFN-γ production. As positive feedback loops, secreted IFN-γ activates STAT1 and elongates its production in NK-92 cells.

Targeting antitumor effect of rhTNF-α fusion protein mediated by matrix metalloproteinase-2

The aim of this study was to examine the tumor therapy, targeting effects and side effects of tumor-targeting rhTNF-α fusion protein mediated by matrix metalloproteinase-2 in an animal model in order to provide experimental data for future development of drugs. The median lethal dose (LD50) was obtained from acute toxicity experiments. The A549 lung cancer xenograft model was established, and then randomly divided into the saline, standard substance, and low-, middle- and high-dose fusion protein experiment groups. Each group was administered drugs for 18 days. The length and width of the xenografts were measured every three days, after which the xenograft growth curve was drawn. The mice were sacrificed in each group following treatment and the tumor volume and weight were measured. The targeting, effectiveness and toxicity of the transformed fusion protein, and pathological changes of tumor and organ tissues were examined by hematoxylin and eosin (H&E) staining. Additionally, biochemical markers were used to detect damage of various organs after protein processing. Cell apoptosis and angiogenesis were determined using terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling (TUNEL) testing and immunohistochemistry, respectively, in different dose groups. Tumor growth was markedly retarded in the high-dose experimental and standard hTNF-α groups with antitumor rates of 85.91 and 72.25%, respectively, as compared with the control group. Furthermore, the tumor tissue showed obvious apoptosis (the apoptotic index was 78.78 and 66.65%, respectively) and pathological changes in the high-dose experimental and standard hTNF-α groups. Tumor angiogenesis in each fusion protein group was inhibited (P<0.01) and the biochemical markers of various organs were greatly reduced in the high-dose experimental group (P<0.05). This finding indicated that slight toxic effects of fusion proteins were evident for the heart, liver and kidney. The reforming fusion protein can therefore target tumor tissues and efficiently kill tumor cells, with few side effects.

Fisetin induces apoptosis in human nonsmall lung cancer cells via a mitochondria-mediated pathway

The present study investigated the apoptotic effects of fisetin, a phenolic compound, against the human nonsmall cell lung cancer cell line, NCI-H460. Fisetin showed dose-dependent cytotoxic activity against NCI-H460 cells, with 50% inhibition of cell viability occurring at a concentration of 75 μg/mL. Fisetin induced both the production of intracellular reactive oxygen species and apoptosis, as evidenced by apoptotic body formation, DNA fragmentation, an increase in the number of sub-G1 phase cells, and mitochondrial membrane depolarization. Moreover, fisetin significantly modulated the expression of apoptosis-associated proteins, resulting in reduced expression of B cell lymphoma-2, increased expression of Bcl-2-associated X protein, and activation of caspase-9 and caspase-3. In addition, pretreatment with a caspase inhibitor blocked fisetin-induced cell death.

Discovery of quinolinone derivatives as potent FLT3 inhibitors

Recently some fms-like tyrosine kinase 3 (FLT3) inhibitors have shown good efficacy in acute myeloid leukemia (AML) patients. In an effort to develop anti-leukemic drugs, we investigated quinolinone derivatives as novel FLT3 inhibitors. Two substituted quinolinones, KR65367 and KR65370 were subjected to FLT3 kinase activity assay and showed potent inhibition against FLT3 kinase activity in vitro, with IC50 of 2.7 and 0.57 nM, respectively. As a measure of selectivity, effects on the activity of other kinases were also tested. Both compounds have negligible activity against Met, Ron, epidermal growth factor receptor, Aurora A, Janus kinase 2, and insulin receptor; with IC50 greater than 10 μM. KR compounds showed strong growth inhibition in MV4;11 AML cells and increased the apoptotic cell death in flow cytometric analyses. A decrease in STAT5 phosphorylation by KR compounds was observed in MV4;11 cells. Furthermore, in vitro evaluation of compounds structurally related to KR65367 and KR65370 showed a good structure-activity relationship.

Shikonin induces cell cycle arrest in human gastric cancer (AGS) by early growth response 1 (Egr1)-mediated p21 gene expression

ETHNOPHARMACOLOGICAL RELEVANCE

Lithospermum erythrorhizon, a naphthoquinone compound derived from a shikonin, has long been used as traditional Chinese medicine for treatment of various diseases, including cancer. To evaluate the cytotoxic effects of shikonin on AGS gastric cancer cells via induction of cell cycle arrest.

MATERIALS AND METHODS

We observed the effects of 12.5-100 ng/mL dosage of shikonin treatment on AGS cancer cell line with the incubation time of 6h. Cytotoxic effects were assessed by measuring the changes in the intracellular ROS, appearance of senescence phenotype, cell cycle progression, CDK and cyclins expression levels upon shikonin treatment. We also examined upon the activation of Egr1-mediated p21 expression, by siRNA transfection, Luciferase assay, and ChIP assay.

RESULTS

In this study, we found that shikonin inhibits cell proliferation by arresting cell cycle progression at the G2/M phase via modulation of p21 in AGS cells. Also, our results revealed that the p21 gene was transactivated by early growth response1 (Egr1) in response to the shikonin treatment. Transient Egr1 expression enhanced shikonin-induced p21 promoter activity, whereas the suppression of Egr1 expression by small interfering RNA attenuated the ability of shikonin to induce p21 promoter activity.

CONCLUSION

Our results suggested that the anti-proliferative activity of shikonin was due to its ability to induce cell cycle arrest via Egr1-p21 signaling pathway. Thus, the work stated here validates the traditional use of shikonin in the treatment of cancer.

Toxicity of daphnane-type diterpenoids from Genkwa Flos and their pharmacokinetic profile in rat

Daphnane-type diterpenoids (DDs) are the main types of plant diterpene orthoesters known and have remarkable biological activities. However, the in vivo toxicity and pharmacokinetic profile of DDs remains unkonwn. The aim of this study was to investigate the toxicity and pharmacokinetic profile of DDs from Genkwa Flos (Thymelaeaceae). The toxicity of diterpenoids was evaluated after oral administration of total diterpenoids extract from Genkwa Flos to rats, and the blood concentration of diterpenoids was analyzed by ultra performance liquid chromatography tandem triple-quadrupole mass spectrometry (UPLC-TQ-MS). The diterpenoids were confirmed to be the toxic components of Genkwa Flos. The pharmacokinetic profile of these diterpenoids was quite different due to their different structures. Although the contents of yuanhuafine and yuanhuapine were low in the extract, the blood concentrations were extremely high. In contrary, the contents of genkwanine F and Wikstroemia factor M1 in the extract were much higher, but they could not be detected in the blood. This result implied that yuanhuafine and yuanhuapine but not genkwanine F and Wikstroemia factor M1 were the potentail toxic components of Genkwa Flos in vivo. This paper shows for the first time the toxicity of diterpenoids from Genkwa Flos was correlated with their blood concentration and when DDs were used for medicinal purposes, their contents in herb as well as their blood concentrations should be considered.

Ohmyungsamycins A and B: cytotoxic and antimicrobial cyclic peptides produced by Streptomyces sp. from a volcanic island

Ohmyungsamycins A and B (1 and 2), which are new cyclic peptides, were isolated from a marine bacterial strain belonging to the Streptomyces genus collected from a sand beach on Jeju, a volcanic island in the Republic of Korea. Based on the interpretation of the NMR, UV, and IR spectroscopic and MS data, the planar structures of 1 and 2 were elucidated as cyclic depsipeptides bearing unusual amino acid units, including N-methyl-4-methoxytrytophan, β-hydroxyphenylalanine, and N,N-dimethylvaline. The absolute configurations of the α-carbons of the amino acid residues were determined using the advanced Marfey's method. The configurations of the additional stereogenic centers at the β-carbons of the threonine, N-methylthreonine, and β-hydroxyphenylalanine units were assigned by GITC (2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate) derivatization and the modified Mosher's method. We have developed a new method utilizing PGME (phenylglycine methyl ester) derivatization coupled with chromatographic analysis to determine the absolute configuration of N,N-dimethylvaline. Our first successful establishment of the absolute configuration of N,N-dimethylvaline using PGME will provide a general and convenient analytical method for determining the absolute configurations of amino acids with fully substituted amine groups. Ohmyungsamycins A and B showed significant inhibitory activities against diverse cancer cells as well as antibacterial effects.

Extracellular signal-regulated kinase is a direct target of the anti-inflammatory compound amentoflavone derived from Torreya nucifera

Amentoflavone is a biflavonoid compound with antioxidant, anticancer, antibacterial, antiviral, anti-inflammatory, and UV-blocking activities that can be isolated from Torreya nucifera, Biophytum sensitivum, and Selaginella tamariscina. In this study, the molecular mechanism underlying amentoflavone's anti-inflammatory activity was investigated. Amentoflavone dose dependently suppressed the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂) in RAW264.7 cells stimulated with the TLR4 ligand lipopolysaccharide (LPS; derived from Gram-negative bacteria). Amentoflavone suppressed the nuclear translocation of c-Fos, a subunit of activator protein (AP)-1, at 60 min after LPS stimulation and inhibited the activity of purified and immunoprecipitated extracellular signal-regulated kinase (ERK), which mediates c-Fos translocation. In agreement with these results, amentoflavone also suppressed the formation of a molecular complex including ERK and c-Fos. Therefore, our data strongly suggest that amentoflavone's immunopharmacological activities are due to its direct effect on ERK.

Antimetastatic effect of halichondramide, a trisoxazole macrolide from the marine sponge Chondrosia corticata, on human prostate cancer cells via modulation of epithelial-to-mesenchymal transition

Halichondramide (HCA), a trisoxazole-containing macrolide isolated from the marine sponge Chondrosia corticata has been shown to exhibit cytotoxicity and antifungal activities. In our previous study, HCA was also found to exhibit antiproliferative activity against a variety of cancer cells. However, the precise mechanism of action of HCA in the antitumor activity remains to be elucidated. In the present study, we identified the antimetastatic activity of HCA in the highly metastatic PC3 human prostate cancer cells. HCA showed potent growth inhibitory activity of the PC3 cells with an IC₅₀ value of 0.81 µM. Further analysis revealed that HCA suppressed the expression of a potential metastatic biomarker, phosphatase of regenerating liver-3 (PRL-3), in PC3 cells. The suppression of PRL-3 by HCA sequentially down-regulates the expression of phosphoinositide 3-kinase (PI3K) subunits p85 and p110. The antimetastatic effect of HCA was also correlated with the down-regulation of matrix metalloproteases (MMPs) and the modulation of cadherin switches N-cadherin and E-cadherin. In addition, HCA also effectively suppressed the migration and invasion of PC3 cells. These findings suggest that halichondramide might serve as a potential inhibitor of tumor cell metastasis with the modulation of PRL-3.

AP-1/IRF-3 Targeted Anti-Inflammatory Activity of Andrographolide Isolated from Andrographis paniculata

Andrographolide (AG) is an abundant component of plants of the genus Andrographis and has a number of beneficial properties including neuroprotective, anticancer, anti-inflammatory, and antidiabetic effects. Despite numerous pharmacological studies, the precise mechanism of AG is still ambiguous. Thus, in the present study, we investigated the molecular mechanisms of AG and its target proteins as they pertain to anti-inflammatory responses. AG suppressed the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂), as well as the mRNA abundance of inducible NO synthase (iNOS), tumor necrosis factor-alpha (TNF-α), cyclooxygenase (COX)-2, and interferon-beta (IFN-β) in a dose-dependent manner in both lipopolysaccharide- (LPS-) activated RAW264.7 cells and peritoneal macrophages. AG also substantially ameliorated the symptoms of LPS-induced hepatitis and EtOH/HCl-induced gastritis in mice. Based on the results of luciferase reporter gene assays, kinase assays, and measurement of nuclear levels of transcription factors, the anti-inflammatory effects of AG were found to be clearly mediated by inhibition of both (1) extracellular signal-regulated kinase (ERK)/activator protein (AP)-1 and (2) IκB kinase ε (IKKε)/interferon regulatory factor (IRF)-3 pathways. In conclusion, we detected a novel molecular signaling pathway by which AG can suppress inflammatory responses. Thus, AG is a promising anti-inflammatory drug with two pharmacological targets.