Protopine, a novel microtubule-stabilizing agent, causes mitotic arrest and apoptotic cell death in human hormone-refractory prostate cancer cell lines

Exploring Anticancer Properties of Medicinal Plants against Breast Cancer by Downregulating Human Epidermal Growth Factor Receptor 2

Plants have a history of being employed in managing breast cancer. However, no scientific evidence supports the idea that these plants can effectively reduce the level of HER2 expression. In this study, extracts from 10 medicinal plants were evaluated for their anticancer properties against HER2-positive breast cancer cells through various methods, including the SRB assay, comet assay, annexin V-FITC dual staining, and immunoblotting. All extracts exerted antiproliferative activity against HER2-positive breast cancer cells. Furthermore, Terminalia chebula (T. chebula), Berberis aristata (B. aristata), and Mucuna pruriens (M. pruriens) reduced HER2 expression in tested cell lines. In addition, an increased Bax/Bcl-2 ratio was observed after the treatment. A comparative proteomics study showed modulation in the proteome profile of breast cancer cells after treatment with T. chebula, B. aristata, Punica granatum, M. pruriens, and Acorus calamus. Metabolic profiling of lead plants revealed the existence of multiple anticancer compounds. Our study demonstrates the considerable potential of the mentioned plants as innovative therapies for HER2-positive breast cancer.

Two new isoquinoline alkaloids from Hypecoum leptocarpum Hook. f. et Thoms

Two new isoquinoline alkaloids, hypecocarpinine (1) and leptocaramine (2) along with five known ones including leptopidine (3), corydamine (4), protopine (5), dihydroprotopine (6) and oxohydrastinine (7), were isolated from Hypecoum leptocarpum Hook. f. et Thoms. Structures of the compounds were elucidated using spectroscopic methods, including UV, IR, HR-ESI-MS, 1 D and 2 D NMR. The cytotoxic activities of these compounds were evaluated using MTT assay. The results showed that compounds 2, 4, and 7 have moderate cytotoxicity against human lung cancer (A549) and human gastric carcinoma (MGC-803) cell lines.

The composition, pharmacological effects, related mechanisms and drug delivery of alkaloids from Corydalis yanhusuo

Corydalis yanhusuo W. T. Wang, also known as yanhusuo, yuanhu, yanhu and xuanhu, is one of the herb components of many Chinese Traditional Medicine prescriptions such as Jin Ling Zi San and Yuanhu-Zhitong priscription. C. yanhusuo was traditionally used to relieve pain and motivate blood and Qi circulation. Now there has been growing interest in pharmacological effects of alkaloids, the main bioactive components of C. yanhusuo. Eighty-four alkaloids isolated from C. yanhusuo are its important bioactive components and can be characterized into protoberberine alkaloids, aporphine alkaloids, opiate alkaloids and others and proper extraction or co-administration methods modulate their contents and efficacy. Alkaloids from C. yanhusuo have various pharmacological effects on the nervous system, cardiovascular system, cancer and others through multiple molecular mechanisms such as modulating neurotransmitters, ion channels, gut microbiota, HPA axis and signaling pathways and are potential treatments for many diseases. Plenty of novel drug delivery methods such as autologous red blood cells, self-microemulsifying drug delivery systems, nanoparticles and others have also been investigated to better exert the effects of alkaloids from C. yanhusuo. This review summarized the alkaloid components of C. yanhusuo, their pharmacological effects and mechanisms, and methods of drug delivery to lay a foundation for future investigations.

Crosstalk between Microtubule Stabilizing Agents and Prostate Cancer

A variety of microtubule-stabilizing cytotoxic agents (MSA) with diverse chemical scaffolds have been discovered from marine sponges, microorganisms, and plants. Two MSAs, docetaxel and cabazitaxel, are the exclusive chemotherapeutics that convey a survival benefit in patients with castration-resistant prostate cancer (CRPC). Additional MSAs have been investigated for their potential in treating prostate cancer in both clinical and preclinical settings. Independent of promoting mitotic arrest, MSAs can suppress the nuclear accumulation of androgen receptor (AR), which is the driving force for prostate cancer cell growth and progression. The alternative mechanism not only helps to better understand the clinical efficacy of docetaxel and cabazitaxel for AR-driven CRPC but also provides an avenue to seek better treatments for various forms of prostate cancer. The dual mechanisms of action enable MSAs to suppress AR-null prostate cancer cell proliferation by cell mitosis pathway and to interfere with the AR signaling pathway in AR positive cells. MSA chemotherapeutics, being administered alone or in combination with other therapeutics, may serve as the optimal therapeutic option for patients with either castration-sensitive or castration-resistant prostate cancer. This review provides an overview of the anti-prostate cancer profiles (including preclinical and clinical studies, and clinical use) of diverse MSAs, as well as the mechanism of action.

Administration of protopine prevents mitophagy and acute lung injury in sepsis

Introduction: Sepsis is a severe life-threatening infection that induces a series of dysregulated physiologic responses and results in organ dysfunction. Acute lung injury (ALI), the primary cause of respiratory failure brought on by sepsis, does not have a specific therapy. Protopine (PTP) is an alkaloid with antiinflammatory and antioxidant properties. However, the function of PTP in septic ALI has not yet been documented. This work sought to investigate how PTP affected septic ALI and the mechanisms involved in septic lung damage, including inflammation, oxidative stress, apoptosis, and mitophagy. Methods: Here, we established a mouse model induced by cecal ligation and puncture (CLP) and a BEAS-2B cell model exposed to lipopolysaccharide (LPS). Results: PTP treatment significantly reduced mortality in CLP mice. PTP mitigated lung damage and reduced apoptosis. Western blot analysis showed that PTP dramatically reduced the expression of the apoptosis-associated protein (Cleaved Caspase-3, Cyto C) and increased Bcl-2/Bax. In addition, PTP decreased the production of inflammatory cytokines (IL-6, IL-1β, TNF-α), increased glutathione (GSH) levels and superoxide dismutase (SOD) activity, and decreased malondialdehyde (MDA) levels. Meanwhile, PTP significantly reduced the expression of mitophagy-related proteins (PINK1, Parkin, LC-II), and downregulated mitophagy by transmission electron microscopy. Additionally, the cells were consistent with animal experiments. Discussion: PTP intervention reduced inflammatory responses, oxidative stress, and apoptosis, restored mitochondrial membrane potential, and downregulated mitophagy. The research shows that PTP prevents excessivemitophagy and ALI in sepsis, suggesting that PTP has a potential role in the therapy of sepsis.

Natural-Derived COX-2 Inhibitors as Anticancer Drugs: A Review of their Structural Diversity and Mechanism of Action

Cyclooxygenase-2 (COX-2) is a key-type enzyme playing a crucial role in cancer development, making it a target of high interest for drug designers. In the last two decades, numerous selective COX-2 inhibitors have been approved for various clinical conditions. However, data from clinical trials propose that the prolonged use of COX-2 inhibitors is associated with life-threatening cardiovascular side effects. The data indicate that a slight structural modification can help develop COX-2 selective inhibitors with comparative efficacy and limited side effects. In this regard, secondary metabolites from natural sources offer great hope for developing novel COX-2 inhibitors with potential anticancer activity. In recent years, various nature-derived organic scaffolds are being explored as leads for developing new COX-2 inhibitors. The current review attempts to highlight the COX-2 inhibition activity of some naturally occurring secondary metabolites, concerning their capacity to inhibit COX-1 and COX-2 enzymes and inhibit cancer development, aiming to establish a structure-activity relationship.

1-(4-((5-chloro-4-((2-(isopropylsulfonyl)phenyl)amino)pyrimidin-2-yl)amino)-3-methoxyphenyl)-3-(2-(dimethylamino)ethyl)imidazolidin-2-one (ZX-42) inhibits cell proliferation and induces apoptosis via inhibiting ALK and its downstream pathways in Karpas299 cells

Anaplastic lymphoma kinase (ALK) belongs to the family of receptor tyrosine kinases. Recently, the incidence of anaplastic large cell lymphoma (ALCL) with ALK rearrangement has raised considerably. The application of ALK-targeted inhibitors such as ceritinib provides an effective therapy for the treatment of ALK-positive cancers. However, with the prolongation of treatment time, the emergence of resistance is inevitable. We found that 1-(4-((5-chloro-4-((2-(isopropylsulfonyl)phenyl)amino)pyrimidin-2-yl)amino)-3-methoxyphenyl)-3-(2-(dimethylamino)ethyl)imidazolidin-2-one (ZX-42), a novel ceritinib derivative, could inhibit the proliferation of ALK-positive ALCL cells, induce the apoptosis of Karpas299 cells through the mitochondrial pathway in a caspase-dependent manner. In addition, ZX-42 could suppress ALK and downstream pathways including PI3K/Akt, Erk and JAK3/STAT3 and reduce the nuclear translocation of NFκB by inhibiting TRAF2/IKK/IκB pathway. Taken together, our findings indicate that ZX-42 shows more effective activity than ceritinib against ALK-positive ALCL. We hope this study can provide a direction for the structural modification of ceritinib and lay the foundation for the further development of clinical research in ALK-positive ALCL.

The other side of the coin: Positive view on the role of opioids in cancer

Opioids have been used for medicinal purposes as an analgesic and recreational purposes as a euphorigenic throughout human history. Cancer patients are often treated with different doses of opioids concurrently with anti-cancer drugs for pain relief without exhibiting excessive adverse effects. The intersection of the biology of pain, opioid therapy, and disease progression represents the crux of the matters and is of potentially great importance in cancer care. For more than 20 years, multiple investigations have focused on the stimulatory effects of opioids on cancer cell growth, while in-depth studies on the inhibitory effects on cancer cell growth development have usually been neglected. This paper reviews the evidence regarding opioid therapies and their anti-cancer effects on various malignancies. Likewise, we have a glimpse into the molecular mechanisms necessary for pinpointing their positive or negative impacts on malignancies to raise awareness and stimulate more excellent dialogue regarding their carcinogenic/anticarcinogenic roles.

Wangzaozin A, a potent novel microtubule stabilizer, targets both the taxane and laulimalide sites on β-tubulin through molecular dynamics simulations

Wangzaozin A, an ent-kaurene diterpenoid isolated from Isodon racemosa (Hemsl) Hara, promotes the polymerization of intracellular microtubules as well as purified tubulin, which is similar to other known microtubule stabilizers. Our pharmacological results showed that wangzaozin A induced G2/M cell cycle arrest and the significant inhibition of cancer cell proliferation. A molecular docking study indicated that wangzaozin A could bind to both the taxane and laulimalide (lau) sites on β-tubulin, which is a novel binding mode that differs from that of known microtubule stabilizers. Furthermore, molecular dynamics simulation and binding free energy calculations demonstrated that wangzaozin A could stably bind to taxane and lau sites simultaneously and form a double-bonded complex. The binding mode of wangzaozin A to the taxane site was more similar to that of epothilone A than paclitaxel. Our results demonstrate that wangzaozin A represents a novel class of microtubule stabilizers, and may serve as a potential microtubule-targeting lead compound for further structural optimization.

Identification and Quantification, Metabolism and Pharmacokinetics, Pharmacological Activities, and Botanical Preparations of Protopine: A Review

Through pharmacological activity research, an increasing number of natural products and their derivatives are being recognized for their therapeutic value. In recent years, studies have been conducted on Corydalis yanhusuo W.T. Wang, a valuable medicinal herb listed in the Chinese Pharmacopoeia. Protopine, one of its components, has also become a research hotspot. To illustrate the identification, metabolism, and broad pharmacological activity of protopine and the botanical preparations containing it for further scientific studies and clinical applications, an in-depth and detailed review of protopine is required. We collected data on the identification and quantification, metabolism and pharmacokinetics, pharmacological activities, and botanical preparations of protopine from 1986 to 2021 from the PubMed database using “protopine” as a keyword. It has been shown that protopine as an active ingredient of many botanical preparations can be rapidly screened and quantified by a large number of methods (such as the LC-ESI-MS/MS and the TLC/GC-MS), and the possible metabolic pathways of protopine in vivo have been proposed. In addition, protopine possesses a wide range of pharmacological activities such as anti-inflammatory, anti-platelet aggregation, anti-cancer, analgesic, vasodilatory, anticholinesterase, anti-addictive, anticonvulsant, antipathogenic, antioxidant, hepatoprotective, neuroprotective, and cytotoxic and anti-proliferative activities. In this paper, the identification and quantification, metabolism and pharmacokinetics, pharmacological activities, and botanical preparations of protopine are reviewed in detail to lay a foundation for further scientific research and clinical applications of protopine.

Effect of protopine exposure on the physiology and gene expression in the bloom-forming cyanobacterium Microcystis aeruginosa

Environment-friendly sound measures with high algal growth inhibition efficiency are required to control and eliminate CyanoHABs. This study examined the effects of protopine on growth, gene expression, and antioxidant system of the M. aeruginosa TY001 and explored possible damage mechanism. The results revealed that higher concentrations of protopine seriously inhibited the growth of M. aeruginosa. Quantitative real-time PCR analysis showed downregulated expression of stress response genes (prx and fabZ), and DNA repair gene (recA) on days 3 and 5. The activities of antioxidant enzymes were also decreased markedly, including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). Additionally, protopine stress can significantly increase the malondialdehyde (MDA) level in cells. In conclusion, oxidative damage and DNA damage are the main mechanisms of protopine inhibition on M. aeruginosa TY001. Our studies provide evidence that alkaloid compounds such as protopine may have a potential use value as components of aquatic management strategies.

Phosphoproteomics Identifies Significant Biomarkers Associated with the Proliferation and Metastasis of Prostate Cancer

The spider peptide toxins HNTX-III and JZTX-I are a specific inhibitor and activator of TTX-S VGSCs, respectively. They play important roles in regulating MAT-LyLu cell metastasis in prostate cancer. In order to identify key biomarkers involved in the regulation of MAT-LyLu cell metastasis, iTRAQ-based quantitative phosphoproteomics analysis was performed on cells treated with HNTX-III, JZTX-I and blank. A total of 554 unique phosphorylated proteins and 1779 distinct phosphorylated proteins were identified, while 55 and 36 phosphorylated proteins were identified as differentially expressed proteins in HNTX-III and JZTX-I treated groups compared with control groups. Multiple bioinformatics analysis based on quantitative phosphoproteomics data suggested that the differentially expressed phosphorylated proteins and peptides were significantly associated with the migration and invasion of prostate tumors. Specifically, the toxins HNTX-III and JZTX-I have opposite effects on tumor formation and metastasis by regulating the expression and phosphorylation level of causal proteins. Herein, we highlighted three key proteins EEF2, U2AF2 and FLNC which were down-regulated in HNTX-III treated cells and up-regulated in JZTX-I treated cells. They played significant roles in cancer related physiological and pathological processes. The differentially expressed phosphorylated proteins identified in this study may serve as potential biomarkers for precision medicine for prostate cancer in the near future.

Protopine triggers apoptosis via the intrinsic pathway and regulation of ROS/PI3K/Akt signalling pathway in liver carcinoma

Background

Protopine is an isoquinoline alkaloid that possesses various biological activities including the anti-tumour activity. However, the effects of protopine on liver carcinoma cells are still elusive. The aim of this study is to examine the effects of protopine on liver carcinoma cells both in vitro and in vivo.

Methods

MTT assay was performed to measure the cell viability. Wound healing and transwell assays were conducted to assess the motility of cells. Cellular apoptosis and ROS levels were measured by the flow cytometry. Western blotting assay was used to measure the change of proteins. The cytotoxicity of protopine was also evaluated in xenograft mice.

Results

Protopine inhibited viabilities and triggered apoptosis via the intrinsic pathway in a caspase-dependent manner in liver carcinoma cells. Furthermore, protopine also induced accumulation of intracellular ROS which further led to the inhibition of PI3K/Akt signalling pathway. Finally, in vivo study showed that protopine also repressed tumour growth in xenograft mice without noticeable toxicity.

Conclusions

Protopine might be used as a potential therapeutic agent for the treatment of liver carcinoma.

Pinocembrin Promotes OPC Differentiation and Remyelination via the mTOR Signaling Pathway

The exacerbation of progressive multiple sclerosis (MS) is closely associated with obstruction of the differentiation of oligodendrocyte progenitor cells (OPCs). To discover novel therapeutic compounds for enhancing remyelination by endogenous OPCs, we screened for myelin basic protein expression using cultured rat OPCs and a library of small-molecule compounds. One of the most effective drugs was pinocembrin, which remarkably promoted OPC differentiation and maturation without affecting cell proliferation and survival. Based on these in vitro effects, we further assessed the therapeutic effects of pinocembrin in animal models of demyelinating diseases. We demonstrated that pinocembrin significantly ameliorated the progression of experimental autoimmune encephalomyelitis (EAE) and enhanced the repair of demyelination in lysolectin-induced lesions. Further studies indicated that pinocembrin increased the phosphorylation level of mammalian target of rapamycin (mTOR). Taken together, our results demonstrated that pinocembrin promotes OPC differentiation and remyelination through the phosphorylated mTOR pathway, and suggest a novel therapeutic prospect for this natural flavonoid product in treating demyelinating diseases.

Cytotoxicity and apoptosis induction by Fumaria officinalis extracts in leukemia and multiple myeloma cell lines

ETHNOPHARMACOLOGICAL RELEVANCE

Fumaria officinalis (Fumariaceae) is recorded in the Kurdish ethnobotany for various health problems.

AIM OF THE STUDY

In this study, the cytotoxic activity of F. officinalis extracts on two leukemia and nine multiple myeloma (MM) cell lines was investigated.

MATERIALS AND METHODS

The cytotoxic and ferroptotic activity were examined by resazurin reduction assay. Flow cytometry, immunoblotting assay and fluorescence microscopy were used to measure cell cycle distribution, apoptosis, induction of reactive oxygen species (ROS), loss integrity of mitochondrial membrane potential (MMP) and autophagy. LC-ESI/MS was used to identify chemical constituents present in F. officinalis.

RESULTS

Chloroform (CF) and ethyl acetate (EF) fractions showed drastic cytotoxic effect on CCRF-CEM and CEM/ADR 5000 cells. NCI-H929 cell line exhibited higher sensitivity against CF, while EF demonstrated its higher cytotoxicity on OPM-2 cells with IC₅₀ value 14.80 ± 1.70 and 28.13 ± 1.38 μg/mL respectively. Flow cytometric and morphological studies confirmed that CF and EF induced apoptosis in NCI-H929 cells by loss of MMP, generation of ROS and obvious morphological variations. In DNA histograms, up to 50% of the cells were accumulated by CF and 44% by EF in the sub-G0/G1 phase following 72 h treatment. EF induced autophagic cell death, while CF stimulated iron-dependent cell death. Moreover, two isoquinoline alkaloids and four flavonoids were identified in the active fractions.

CONCLUSION

To our knowledge, this is the first report demonstrating the cytotoxicity of F. officinalis extracts in MM cell lines. CF and EF fractions inhibited MM cell proliferation through various modes of actions.

The Anticancer Effect of Natural Plant Alkaloid Isoquinolines

Isoquinoline alkaloids-enriched herbal plants have been used as traditional folk medicine for their anti-inflammatory, antimicrobial, and analgesic effects. They induce cell cycle arrest, apoptosis, and autophagy, leading to cell death. While the molecular mechanisms of these effects are not fully understood, it has been suggested that binding to nucleic acids or proteins, enzyme inhibition, and epigenetic modulation by isoquinoline alkaloids may play a role in the effects. This review discusses recent evidence on the molecular mechanisms by which the isoquinoline alkaloids can be a therapeutic target of cancer treatment.

Protopine/Gemcitabine Combination Induces Cytotoxic or Cytoprotective Effects in Cell Type-Specific and Dose-Dependent Manner on Human Cancer and Normal Cells

The natural alkaloid protopine (PRO) exhibits pharmacological properties including anticancer activity. We investigated the effects of PRO, alone and in combination with the chemotherapeutic gemcitabine (GEM), on human tumor cell lines and non-tumor human dermal fibroblasts (HDFs). We found that treatments with different PRO/GEM combinations were cytotoxic or cytoprotective, depending on concentration and cell type. PRO/GEM decreased viability in pancreatic cancer MIA PaCa-2 and PANC-1 cells, while it rescued the GEM-induced viability decline in HDFs and in tumor MCF-7 cells. Moreover, PRO/GEM decreased G1, S and G2/M phases, concomitantly with an increase of subG1 phase in MIA PaCa-2 and PANC-1 cells. Differently, PRO/GEM restored the normal progression of the cell cycle, altered by GEM, and decreased cell death in HDFs. PRO alone increased mitochondrial reactive oxygen species (ROS) in MIA PaCa-2, PANC-1 cells and HDFs, while PRO/GEM increased both intracellular and mitochondrial ROS in the three cell lines. These results indicate that specific combinations of PRO/GEM may be used to induce cytotoxic effects in pancreatic tumor MIA PaCa-2 and PANC-1 cells, but have cytoprotective or no effects in HDFs.

Identification and Characterization of the Lactating Mouse Mammary Gland Citrullinome

Citrullination is a post-translational modification (PTM) in which positively charged peptidyl-arginine is converted into neutral peptidyl-citrulline by peptidylarginine deiminase (PAD or PADI) enzymes. The full protein citrullinome in many tissues is unknown. Herein, we used mass spectrometry and identified 107 citrullinated proteins in the lactation day 9 (L9) mouse mammary gland including histone H2A, α-tubulin, and β-casein. Given the importance of prolactin to lactation, we next tested if it stimulates PAD-catalyzed citrullination using mouse mammary epithelial CID-9 cells. Stimulation of CID-9 cells with 5 µg/mL prolactin for 10 min induced a 2-fold increase in histone H2A citrullination and a 4.5-fold increase in α-tubulin citrullination. We next investigated if prolactin-induced citrullination regulates the expression of lactation genes β-casein (Csn2) and butyrophilin (Btn1a1). Prolactin treatment for 12 h increased β-casein and butyrophilin mRNA expression; however, this increase was significantly inhibited by the pan-PAD inhibitor, BB-Cl-amidine (BB-ClA). We also examined the effect of tubulin citrullination on the overall polymerization rate of microtubules. Our results show that citrullinated tubulin had a higher maximum overall polymerization rate. Our work suggests that protein citrullination is an important PTM that regulates gene expression and microtubule dynamics in mammary epithelial cells.

Traditional uses, phytochemistry, and pharmacology of Ficus hispida L.f.: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Ficus hispida L.f. (Moraceae) has long been used as a traditional medicine in India, China, Sri Lanka, Australia, and Myanmar in the treatment of diarrhea, ulcer, anemia, diabetes, inflammation, and cancer.

AIM OF THE REVIEW

This review provides a systematic comment on the botany, traditional uses, and phytochemical and pharmacological studies of F. hispida, with an aim to make critical update of the current knowledge and obtain opportunities for further therapeutic potential.

MATERIALS AND METHODS

The information was derived from scientific literature databases including PubMed, Baidu Scholar, Google Scholar, Web of Science, and Science Direct. Additional information was gathered from books, Ph.D. and M.Sc. dissertations, and unpublished materials.

RESULTS AND DISCUSSION

F. hispida is used especially in Chinese and Indian traditional medical systems as a remedy for skin disorders, respiratory diseases, and urinary diseases. Wound healing, anti-inflammatory, antinociceptive, sedative, antidiarrheal, antiulcer, antimicrobial, antioxidant, hepatoprotective, antineoplastic, and antidiabetic activities have been reported for crude extracts and isolated metabolites, but the methodologies in these studies often have inadequate design and low technical quality. More than 76 compounds have been isolated from F.hispida, including sesquiterpenoids and triterpenoids, flavonoids, coumarins, phenylpropionic acids, benzoic acid derivatives, alkaloids, steroids, other glycosides, and alkanes, but the method of bioassay-guided fractionation is seldom applied in the isolation from F. hispida.

CONCLUSION

F. hispida is used widely in traditional medicines and has multiple pharmacological effects that could support traditional uses. However, pharmacological studies should be viewed with caution because of the inappropriate experimental design. More in vitro and in vivo research is urgently needed to study the molecular mechanisms and assess the effective and safe dose of F. hispida.

Protopine attenuates inflammation stimulated by carrageenan and LPS via the MAPK/NF-κB pathway

We investigated the anti-inflammatory activity of protopine (PTP) and sought to determine its mechanism of action in LPS-stimulated BV2 cells and a carrageenan (CA)-induced mouse model. Treatment with PTP (5, 10, and 20 μM) significantly suppresses the secretion of NO and PGE₂ in a concentration-dependent manner without affecting cell viability by downregulating iNOS and COX-2 expression in LPS-induced BV2 cells. PTP also attenuates the production of pro-inflammatory chemokines, such as MCP-1, and cytokines, including TNF-α, IL-1β and IL-6, and augments the expression of the anti-inflammatory cytokine IL-10. In addition, PTP suppresses the nuclear translocation of NF-κB by hindering the degradation of IκB and downregulating the expression of mitogen-activated protein kinases (MAPKs), including p38, ERK1/2 and JNK protein. Furthermore, PTP treatment significantly suppresses CA-induced paw oedema in mice compared to that seen in untreated mice. Expression of iNOS and COX-2 proteins is also abrogated by PTP (50 mg/kg) treatment in CA-induced mice. PTP treatment also abolishes IκB phosphorylation, which hinders the activation of NF-κB. Collectively, these results suggest PTP has potential for attenuating CA- and LPS-induced inflammatory symptoms through modulation of MAPKs/NF-κB signaling cascades.

Protopine isolated from Nandina domestica induces apoptosis and autophagy in colon cancer cells by stabilizing p53

The tumor suppressor p53 plays essential roles in cellular protection mechanisms against a variety of stress stimuli and its activation induces apoptosis or autophagy in certain cancer cells. Here, we identified protopine, an isoquinoline alkaloid isolated from Nandina domestica, as an activator of the p53 pathway from cell-based natural compound screening based on p53-responsive transcription. Protopine increased the p53-mediated transcriptional activity and promoted p53 phosphorylation at the Ser15 residue, resulting in stabilization of p53 protein. Moreover, protopine up-regulated the expression of p21^WAF1/CIP1 and BAX, downstream genes of p53, and inhibited the proliferation of HCT116 colon cancer cells. Apoptosis was elicited by protopine as indicated by caspase-3/7 activation, poly ADP ribose polymerase cleavage, and increased population of Annexin V-FITC-positive cells. Furthermore, protopine induced the formation of microtubule-associated protein 1 light chain 3 (LC3) puncta and LC3-II turnover, typical biochemical markers of autophagy, in HCT116 cells. Our findings suggest that protopine exerts its antiproliferative activity by stimulating the p53 pathway and may have potential as a chemopreventive agent for human colon cancer.

Isolation of 4,4'-bond secalonic acid D from the marine-derived fungus Penicillium oxalicum with inhibitory property against hepatocellular carcinoma

4,4'-bond secalonic acid D (4,4'-SAD) is a known compound isolated from the marine-derived fungus Penicillium oxalicum. No study about the antitumor effect of this compound has been reported, except for a few focusing on its bactericidal properties. Herein, we performed an in vitro biology test and found that 4,4'-SAD stimulated the apoptosis of tumor cells in the human hepatocellular carcinoma cell lines PLC/PRF/5 and HuH-7 by activating caspase-3, caspase-8, caspase-9, PARP, p53, and cyclin B1, as well as by regulating the Bax/Bcl-2 ratio. In vivo studies showed that 4,4'-SAD had antitumor efficacy in H22 cell xenograft model. Immunohistochemical analysis revealed that 4,4'-SAD could regulate Bax expression, which is a biomarker of tumor growth. In summary, 4,4'-SAD significantly inhibited tumor growth both in vivo and in vitro.

Identification of 7-(4'-Cyanophenyl)indoline-1-benzenesulfonamide as a mitotic inhibitor to induce apoptotic cell death and inhibit autophagy in human colorectal cancer cells

Targeting cellular mitosis in tumor cells is an attractive cancer treatment strategy. Here, we report that B220, a synthetic benzenesulfonamide compound, could represent a new mitotic inhibitor for the treatment of colorectal cancer. We examined the action mechanism of B220 in the colorectal carcinoma HCT116 cell line, and found that treatment of cells with B220 caused cells to accumulate in G2/M phase, with a concomitant induction of the mitotic phase markers, MPM2 and cyclin B1. After 48 h of B220 treatment, cells underwent apoptotic cell death via caspase-3 activation and poly(ADP ribose) polymerase (PARP) cleavage. In addition, B220 inhibits autophagy by blocking conversion of microtubule-associated protein 1 light chain 3 (LC3-I) to LC3-II and inhibiting autophagic flux. Notably, blockade of autophagy by pharmacological inhibition or using an Atg5-targeting shRNA reduced B220-induced cytotoxicity. Conversely, the autophagy inducer NVP-BEZ235 shows a synergistic interaction with B220 in HCT116 cells, indicating autophagy was required for the observed cell death. In summary, these results indicate B220 combined with the induction of autophagy using the dual PI3K/mTOR inhibitor, NVP-BEZ235, might be an attractive strategy for cancer therapy, and provides a framework for further development of B220 as a new therapeutic agent for colon cancer treatment.

UPLC-MS/MS Profile of Alkaloids with Cytotoxic Properties of Selected Medicinal Plants of the Berberidaceae and Papaveraceae Families

Cancer is one of the most occurring diseases in developed and developing countries. Plant-based compounds are still researched for their anticancer activity and for their quantity in plants. Therefore, the modern chromatographic methods are applied to quantify them in plants, for example, UPLC-MS/MS (ultraperformance liquid chromatography tandem mass spectrometry). Therefore, the aim of the present study was to evaluate the content of sanguinarine, berberine, protopine, and chelidonine in Dicentra spectabilis (L.) Lem., Fumaria officinalis L., Glaucium flavum Crantz, Corydalis cava L., Berberis thunbergii DC., Meconopsis cambrica (L.) Vig., Mahonia aquifolium (Pursh) Nutt., Macleaya cordata Willd., and Chelidonium majus L. For the first time, N,N-dimethyl-hernovine was identified in M. cambrica, B. thunbergii, M. aquifolium, C. cava, G. flavum, and C. majus; methyl-hernovine was identified in G. flavum; columbamine was identified in B. thunbergii; and methyl-corypalmine, chelidonine, and sanguinarine were identified in F. officinalis L. The richest source of protopine among all the examined species was M. cordata (5463.64 ± 26.3 μg/g). The highest amounts of chelidonine and sanguinarine were found in C. majus (51,040.0 ± 1.8 μg/g and 7925.8 ± 3.3 μg/g, resp.), while B. thunbergi contained the highest amount of berberine (6358.4 ± 4.2 μg/g).

5-(Furan-2-yl)-4-(3,4,5-trimethoxyphenyl)-3H-1,2-dithiol-3-one oxime (6f), a new synthetic compound, causes human fibrosarcoma HT-1080 cell apoptosis by disrupting tubulin polymerisation and inducing G2/M arrest

In the current study, we synthesized a series of new compounds targeting tubulin and tested their anti-proliferative activities. Among these new synthetic com-pounds, 5-(furan-2-yl)-4-(3,4,5-trimethoxyphenyl)-3H-1,2-dithiol-3-one oxime (6f) exhibited significant anti-proliferative activity against different human cancer cell lines including human gastric adenocarcinoma SGC-7901, human non-small cell lung cancer A549, and human fibrosarcoma HT-1080. As a result, 6f was selected to further test the sensitivity to different cancer cell lines including human cervical cancer cell line HeLa, human breast cancer cell line MCF-7, non-small cell lung cancer cell line A549, human liver carcinoma cell line HepG-2, human oral squamous cell carcinoma cell lines KB, SGC-7901 and HT-1080. Among these cell lines, HT-1080 and HeLa are the most sensitive. Therefore, HT-1080 was selected to further explore the properties of anti-proliferative activity and the underlying mechanisms. Our data proved that 6f exhibited strong anti-proliferative effects against HT-1080 cells in a time- and dose-dependent manner. We showed that the growth inhibitory effect of 6f in HT-1080 cells was related with microtubule depolymerisation. Molecular docking studies revealed that 6f interacted and bound efficiently with the colchicine-binding site of tubulin. In addition, 6f treatment induced G2/M cell cycle arrest dose-dependently and subsequently induced cell apoptosis. Western blot study indicated that upregulation of cyclin B1 and p-cdc2 was related with G2/M arrest. 6f-induced cell apoptosis was associated with both mitochondrial and death receptor pathway. In conclusion, our data showed that 6f, among the newly synthetic compounds, exhibited highest anti-proliferative activity by disrupting the microtubule polymerisation, causing G2/M arrest and subsequently inducing cell apoptosis in HT-1080 cells. Hence, 6f is a promising microtubule depolymerising agent for the treatment of various cancers especially human fibrosarcoma.

The apoptotic mechanisms of MT-6, a mitotic arrest inducer, in human ovarian cancer cells

Patients with ovarian cancer are typically diagnosed at an advanced stage, resulting in poor prognosis since there are currently no effective early-detection screening tests for women at average-risk for ovarian cancer. Here, we investigated the effects of MT-6, a derivative of moscatilin, in ovarian cancer cells. Our investigation showed that MT-6 inhibited the proliferation and viability of ovarian cancer cells with submicromolar IC₅₀ values. MT-6-treated SKOV3 cells showed significant cell cycle arrest at G2/M phase, followed by an increase in the proportion of cells in a sub-G1 phase. In addition, MT-6 induced a concentration-dependent increase in mitotic markers, mitotic kinases, cell cycle regulators of G2/M transition, and apoptosis-related markers in ovarian cancer cells. MT-6 treatment also induced mitochondrial membrane potential loss, JNK activation, and DR5 expression. Cotreatment of cells with the JNK inhibitor SP600125 considerably attenuated MT-6-induced apoptosis, mitochondria membrane potential loss, DR5 upregulation, and suppression of cell viability. MT-6 also inhibited tumor growth in an SKOV3 xenograft model without significant body weight loss. Together, our findings suggest that MT-6 is a potent anticancer agent with tumor-suppressive activity in vitro and in vivo that could be further investigated for ovarian cancer therapy in the future.

The Interference of Selected Cytotoxic Alkaloids with the Cytoskeleton: An Insight into Their Modes of Action

Alkaloids, the largest group among the nitrogen-containing secondary metabolites of plants, usually interact with several molecular targets. In this study, we provide evidence that six cytotoxic alkaloids (sanguinarine, chelerythrine, chelidonine, noscapine, protopine, homoharringtonine), which are known to affect neuroreceptors, protein biosynthesis and nucleic acids, also interact with the cellular cytoskeleton, such as microtubules and actin filaments, as well. Sanguinarine, chelerythrine and chelidonine depolymerized the microtubule network in living cancer cells (Hela cells and human osteosarcoma U2OS cells) and inhibited tubulin polymerization in vitro with IC50 values of 48.41 ± 3.73, 206.39 ± 4.20 and 34.51 ± 9.47 μM, respectively. However, sanguinarine and chelerythrine did not arrest the cell cycle while 2.5 μM chelidonine arrested the cell cycle in the G₂/M phase with 88.27% ± 0.99% of the cells in this phase. Noscapine and protopine apparently affected microtubule structures in living cells without affecting tubulin polymerization in vitro, which led to cell cycle arrest in the G2/M phase, promoting this cell population to 73.42% ± 8.31% and 54.35% ± 11.26% at a concentration of 80 μM and 250.9 μM, respectively. Homoharringtonine did not show any effects on microtubules and cell cycle, while the known microtubule-stabilizing agent paclitaxel was found to inhibit tubulin polymerization in the presence of MAPs in vitro with an IC50 value of 38.19 ± 3.33 μM. Concerning actin filaments, sanguinarine, chelerythrine and chelidonine exhibited a certain effect on the cellular actin filament network by reducing the mass of actin filaments. The interactions of these cytotoxic alkaloids with microtubules and actin filaments present new insights into their molecular modes of action.

Microtubule-stabilizing agents: New drug discovery and cancer therapy

Microtubule-stabilizing agents (MSAs) have been highly successful in the treatment of cancer in the past 20years. To date, three classes of MSAs have entered the clinical trial stage or have been approved for clinical anticancer chemotherapy, and more than 10 classes of novel structural MSAs have been derived from natural resources. The microtubule typically contains two MSA-binding sites: the taxoid site and the laulimalide/peloruside site. All defined MSAs are known to bind at either of these sites, with subtle but significant differences. MSAs with different binding sites may produce a synergistic effect. Although having been extensively applied in the clinical setting, paclitaxel and other approved MSAs still pose many challenges such as multidrug resistance, low bioavailability, poor solubility, high toxicity, and low passage through the blood-brain barrier. A variety of studies focus on the structure-activity relationship in order to improve the pharmaceutical properties of these agents. Here, the mechanisms of action, advancements in pharmacological research, and clinical developments of defined MSAs during the past decade are discussed. The latest discovered MSAs are also briefly introduced in this review. The increasing number of natural MSAs indicates the potential discovery of more novel, natural MSAs with different structural bases, which will further promote the development of anticancer chemotherapy.

Picropodophyllin causes mitotic arrest and catastrophe by depolymerizing microtubules via insulin-like growth factor-1 receptor-independent mechanism

Picropodophyllin (PPP) is an anticancer drug undergoing clinical development in NSCLC. PPP has been shown to suppress IGF-1R signaling and to induce a G2/M cell cycle phase arrest but the exact mechanisms remain to be elucidated. The present study identified an IGF-1-independent mechanism of PPP leading to pro-metaphase arrest. The mitotic block was induced in human cancer cell lines and in an A549 xenograft mouse but did not occur in normal hepatocytes/mouse tissues. Cell cycle arrest by PPP occurred in vitro and in vivo accompanied by prominent CDK1 activation, and was IGF-1R-independent since it occurred also in IGF-1R-depleted and null cells. The tumor cells were not arrested in G2/M but in mitosis. Centrosome separation was prevented during mitotic entry, resulting in a monopolar mitotic spindle with subsequent prometaphase-arrest, independent of Plk1/Aurora A or Eg5, and leading to cell features of mitotic catastrophe. PPP also increased soluble tubulin and decreased spindle-associated tubulin within minutes, indicating that it interfered with microtubule dynamics. These results provide a novel IGF-1R-independent mechanism of antitumor effects of PPP.

Natural antitubulin agents: importance of 3,4,5-trimethoxyphenyl fragment

Microtubules are polar cytoskeletal filaments assembled from head-to-tail and comprised of lateral associations of α/β-tubulin heterodimers that play key role in various cellular processes. Because of their vital role in mitosis and various other cellular processes, microtubules have been attractive targets for several disease conditions and especially for cancer. Antitubulin is the most successful class of antimitotic agents in cancer chemotherapeutics. The target recognition of antimitotic agents as a ligand is not much explored so far. However, 3,4,5-trimethoxyphenyl fragment has been much highlighted and discussed in such type of interactions. In this review, some of the most important naturally occurring antimitotic agents and their interactions with microtubules are discussed with a special emphasis on the role of 3,4,5-trimethoxyphenyl unit. At last, some emerging naturally occurring antimitotic agents have also been tabulated.

MCL-1 degradation mediated by JNK activation via MEKK1/TAK1-MKK4 contributes to anticancer activity of new tubulin inhibitor MT189

Colchicine site-targeted tubulin inhibitors are a promising type of anticancer drugs. MT189 is a new derivative of MT119, a previously reported colchicine site-binding antitubulin agent. In this study, MT189 was demonstrated to retain the property of MT119 in disrupting microtubulin via binding to the colchicine site, causing mitotic arrest and inducing apoptosis, and to display 8.7-fold enhanced proliferative inhibition in a panel of cancer cells. MT189 was shown to elicit in vivo anticancer effects on MDA-MB-231 xenografts in nude mice, and the tumor growth was suppressed by 35.9% over 14 days. MT189 led to degradation of MCL-1, a member of the antiapoptotic BCL-2 protein family. Its overexpression reduced but its silenced expression increased the apoptotic induction followed by the treatment with MT189. Moreover, the treatment with MT189 caused activation of the MEKK1/TAK1-MKK4-JNK signaling pathway. The activated JNK resulted in phosphorylation of MCL-1, which facilitated its ubiquitination-mediated degradation. Our results show that MT189 inhibits microtubulin polymerization by binding to the colchicine site. Relief of apoptotic suppression by MCL-1 degradation together with mitotic arrest contributes to the anticancer activity of MT189.

Protopine inhibits heterotypic cell adhesion in MDA-MB-231 cells through down-regulation of multi-adhesive factors

BACKGROUND

A Chinese herb Corydalis yanhusuo W.T. Wang that showed anticancer and anti-angiogenesis effects in our previous studies was presented for further studies. In the present study, we studied the anticancer proliferation and adhesion effects of five alkaloids which were isolated from Corydalis yanhusuo.

MATERIALS AND METHODS

MTT dose response curves, cell migration assay, cell invasion assay, as well as three types of cell adhesive assay were performed on MDA-MB-231 human breast cancer cells. The mechanism of the compounds on inhibiting heterotypic cell adhesion were further explored by determining the expression of epidermal growth factor receptor (EGFR), Intercellular adhesion molecule 1 (ICAM-1), αv-integrin, β1-integrin and β5-integrin by western blotting assay.

RESULTS

In five tested alkaloids, only protopine exhibited anti-adhesive and anti-invasion effects in MDA-MB-231 cells, which contributed to the anti-metastasis effect of Corydalis yanhusuo. The results showed that after treatment with protopine for 90 min, the expression of EGFR, ICAM-1, αv-integrin, β1-integrin and β5-integrin were remarkably reduced.

CONCLUSION

The present results suggest that protopine seems to inhibit the heterotypic cell adhesion between MDA-MB-231 cells, and human umbilical vein endothelial cells by changing the expression of adhesive factors.

Identification and quantification of the main active anticancer alkaloids from the root of Glaucium flavum

Glaucium flavum is used in Algerian folk medicine to remove warts (benign tumors). Its local appellations are Cheqiq el-asfar and Qarn el-djedyane. We have recently reported the anti-tumoral activity of Glaucium flavum root alkaloid extract against human cancer cells, in vitro and in vivo. The principal identified alkaloid in the extract was protopine. This study aims to determine which component(s) of Glaucium flavum root extract might possess potent antitumor activity on human cancer cells. Quantitative estimation of Glaucium flavum alkaloids was realized by HPLC-DAD. Glaucium flavum effect on human normal and cancer cell viability was determined using WST-1 assay. Quantification of alkaloids in Glaucium flavum revealed that the dried root part contained 0.84% of protopine and 0.07% of bocconoline (w/w), while the dried aerial part contained only 0.08% of protopine, glaucine as the main alkaloid, and no bocconoline. In vitro evaluation of the growth inhibitory activity on breast cancer and normal cells demonstrated that purified protopine did not reproduce the full cytotoxic activity of the alkaloid root extract on cancer cell lines. On the other hand, bocconoline inhibited strongly the viability of cancer cells with an IC₅₀ of 7.8 μM and only a low cytotoxic effect was observed against normal human cells. Our results showed for the first time that protopine is the major root alkaloid of Glaucium flavum. Finally, we are the first to demonstrate a specific anticancer effect of Glaucium flavum root extract against breast cancer cells, which can be attributed, at least in part, to bocconoline.

Revealing the anti-tumoral effect of Algerian Glaucium flavum roots against human cancer cells

Glaucium flavum (G. flavum) is a plant from the Papaveraceae family native to Algeria where it is used in local traditional medicine to treat warts. G. flavum root crude alkaloid extract inhibited breast cancer cell proliferation and induced G2/M phase cycle arrest and apoptosis without affecting normal cells, which is a highly awaited feature of potential anti-cancer agents. G. flavum significantly reduced growth and vascularization of human glioma tumors on chicken chorioallantoic membrane (CAM) in vivo. The chromatographic profile of the dichloromethane extract of G. flavum root showed the presence of different constituents including the isoquinoline alkaloid protopine, as the major compound. We report for the first time that G. flavum extract may represent a new promising agent for cancer chemotherapy.

TW01001, a novel piperazinedione compound, induces mitotic arrest and autophagy in non-small cell lung cancer A549 cells

Here, we report that TW01001, a novel piperazinedione compound, could be a new mitotic inhibitor for the treatment of non-small cell lung cancer by the following observations in A549 cells: (1) induction of cells to accumulate at G2/M phase, which ultimately led to cell apoptotic death, (2) accumulation of p53 and inhibition of survival signalings, and (3) induction of p53-independent autophagy. Taken together, our data suggested that TW01001 induces autophagy-p53-signaling pathway to cause mitotic arrest and cell growth inhibition in A549 cells and provides the framework for further development as a novel therapeutic agent for lung cancer treatment.