Induction of mitochondrial dependent apoptosis and cell cycle arrest in human promyelocytic leukemia HL-60 cells by an extract from Dorstenia psilurus: a spice from Cameroon

Anticancer acumens of three Annona species: a proportional review

INTRODUCTION

Cumulative pattern of cancer could be seen in day-to-day life with each passing year and, it is becoming a great matter of concern especially to the scientific community worldwide. Alternative treatment methods for various types of cancer are in place and, being continuously worked out. Plant-derived natural substances have shown great results in combating cancer in comparison to chemo and radiotherapies which are toxic besides having serious side effects. In continuation, Annona species, native to America, Africa, Asia and Australia have been used in folk medicines and, are reported to have many anti-carcinogenic substances.

METHODS

For a prudent understanding of Annona species against various cancers, comparative investigation and analysis of three species viz., A. cherimola, A. muricata, and A. squamosa was undertaken through a detailed review of the in-attendance subject. The major scientific biomedical literature databases were consulted and the information available from 2011 until January 2021 was taken into account.

RESULTS

Studies on anti-cancer activities along with the thorough analysis of the findings and the pieces of evidence supporting their anti-proliferative, apoptosis, G₁ cell cycle arrest and cytotoxic effects are described. A. muricata displayed maximum number of anti-cancer activities being revealed by most of its parts with the lowest IC₅₀ values against various cancer cell lines compared to A. cherimola and A. squamosa. On account of the findings, it is advocated that, further detailed studies on anti-cancer explorations of Annona species could be proved fruitful in paving new and innovative methodologies for novel anti-cancer drug discovery and development.

How Should the Worldwide Knowledge of Traditional Cancer Healing Be Integrated with Herbs and Mushrooms into Modern Molecular Pharmacology?

Traditional herbal medicine (THM) is a “core” from which modern medicine has evolved over time. Besides this, one third of people worldwide have no access to modern medicine and rely only on traditional medicine. To date, drugs of plant origin, or their derivates (paclitaxel, vinblastine, vincristine, vinorelbine, etoposide, camptothecin, topotecan, irinotecan, and omacetaxine), are very important in the therapy of malignancies and they are included in most chemotherapeutic regimes. To date, 391,000 plant and 14,000 mushroom species exist. Their medical and biochemical capabilities have not been studied in detail. In this review, we systematized the information about plants and mushrooms, as well as their active compounds with antitumor properties. Plants and mushrooms are divided based on the regions where they are used in ethnomedicine to treat malignancies. The majority of their active compounds with antineoplastic properties and mechanisms of action are described. Furthermore, on the basis of the available information, we divided them into two priority groups for research and for their potential of use in antitumor therapy. As there are many prerequisites and some examples how THM helps and strengthens modern medicine, finally, we discuss the positive points of THM and the management required to transform and integrate THM into the modern medicine practice.

Delivery of acetogenin-enriched Annona muricata Linn leaf extract by folic acid-conjugated and triphenylphosphonium-conjugated poly(glycerol adipate) nanoparticles to enhance toxicity against ovarian cancer cells

The study demonstrated the fabrication of new poly(glycerol adipate) (PGA) nanoparticles decorated with folic acid (FOL-PGA) and triphenylphosphonium (TPP-PGA) and the potential on the delivery of acetogenin-enriched Annona muricata Linn leaf extract to ovarian cancer cells. FOL-PGA and TPP-PGA were successfully synthesized and used to fabricate FOL-decorated nanoparticles (FOL-NPs) and FOL-/TPP- decorated nanoparticles (FOL/TPP-NPs) by blending two polymers at a mass ratio of 1:1. All nanoparticles had small size of around 100 nm, narrow size distribution and high negative surface charge about -30 mV. The stable FOL/TPP-NPs showed highest drug loading of 14.9 ± 1.9% at 1:5 ratio of extract to polymer and reached to 35.8 ± 2.1% at higher ratio. Both nanoparticles released the extract in a biphasic sustained release manner over 5 days. The toxicity of the extract to SKOV3 cells was potentiated by FOL-NPs and FOL/TPP-NPs by 2.0 - 2.6 fold through induction of cell apoptosis. FOL/TPP-NPs showed lower IC₅₀ and higher cellular uptake as compared to FOL-NPs. FOL-NPs exhibited folate receptor-mediated endocytosis. FOL/TPP-NPs provided more advantages than FOL-NPs in terms of stability in physiological fluid, uptake efficiency and targeting ability to mitochondria and showed a promising potential PGA platform for targeted delivery of herbal cytotoxic extracts.

Potent Cytotoxicity of Four Cameroonian Plant Extracts on Different Cancer Cell Lines

In this study, the potential cytotoxicity of four plant extracts originated from Cameroon: Xylopia aethiopica (XA), Imperata cylindrica (IC), Echinops giganteus (EG) and Dorstenia psilurus (DP) were examined in vitro. We tested the anti-proliferative activity of the methanolic extracts of these compounds using MTT assay on seven different human cancer cell lines: HeLa, MDA-MB-231, A549, HepG2, U-87, SK-OV-3 and HL60. Induction of cell death was assessed by cell cycle analysis, apoptosis was determined by Annexin V-FITC binding and caspase 3/7 activity. As well, changes in mitochondrial membrane potential (MMP) and cell migration were tested. The genetic toxicity, using the alkaline comet assay, was evaluated. The studied extracts inhibited the cell proliferation of all tested cancer cell lines with concentration dependent effect over time. All of these extracts mainly induced apoptosis of HeLa cells by the accumulation of hypodiploid cells in the sub-G0/G1 phase and increasing the activity of caspase 3/7, as well they showed potential MMP disturbance and expressed a marked inhibitory effect on cell migration. Assessment of probable genetic toxicity by these extracts revealed no or minimum incidence of genetic toxicity. Therefore, the studied plant extracts are exhibiting potent anticancer activity based upon marked induction of tumor-cell death.

Two isoprenylated flavonoids from Dorstenia psilurus activate AMPK, stimulate glucose uptake, inhibit glucose production and lower glycemia

Root extracts of a Cameroon medicinal plant, Dorstenia psilurus, were purified by screening for AMP-activated protein kinase (AMPK) activation in incubated mouse embryo fibroblasts (MEFs). Two isoprenylated flavones that activated AMPK were isolated. Compound 1 was identified as artelasticin by high-resolution electrospray ionization mass spectrometry and 2D-NMR while its structural isomer, compound 2, was isolated for the first time and differed only by the position of one double bond on one isoprenyl substituent. Treatment of MEFs with purified compound 1 or compound 2 led to rapid and robust AMPK activation at low micromolar concentrations and increased the intracellular AMP:ATP ratio. In oxygen consumption experiments on isolated rat liver mitochondria, compound 1 and compound 2 inhibited complex II of the electron transport chain and in freeze-thawed mitochondria succinate dehydrogenase was inhibited. In incubated rat skeletal muscles, both compounds activated AMPK and stimulated glucose uptake. Moreover, these effects were lost in muscles pre-incubated with AMPK inhibitor SBI-0206965, suggesting AMPK dependency. Incubation of mouse hepatocytes with compound 1 or compound 2 led to AMPK activation, but glucose production was decreased in hepatocytes from both wild-type and AMPKβ1-/- mice, suggesting that this effect was not AMPK-dependent. However, when administered intraperitoneally to high-fat diet-induced insulin-resistant mice, compound 1 and compound 2 had blood glucose-lowering effects. In addition, compound 1 and compound 2 reduced the viability of several human cancer cells in culture. The flavonoids we have identified could be a starting point for the development of new drugs to treat type 2 diabetes.

The in vitro and in vivo antitumor effects of Dracaena cinnabari resin extract on oral cancer

OBJECTIVE

To study the potential for apoptosis induction of Dracaena cinnabari Balf. f methanolic extract (DCBME) on tongue squamous cell carcinoma cell line, H103. We evaluated the chemopreventive activity of DCBME against 4-nitroquinolone-1-oxide (4NQO)-induced tongue carcinogenesis in rat.

DESIGN

Phase contrast microscope, acridine orange/propidium iodide (AO/PI) analysis of cells under fluorescence microscope, annexin-V flow-cytometry, DNA fragmentation, mitochondrial membrane potential, and caspase 3/7, 8 and 9 assays were performed. In vivo study, the rats were given 4NQO in their drinking water. The tongue was subjected to histopathological study to evaluate the incidence of squamous cell carcinoma (SCC).

RESULTS

DCBME showed cytotoxic effect on H103 cells in a dose- and time-dependent manner. Furthermore, DCBME showed low cytotoxic effect on a normal cell line. In H103 cells, it caused cell morphology changes, S and G2/M-phase cell cycle arrest, significant reduction of cell migration and induced apoptosis through the intrinsic (mitochondrial) pathway. The incidence of SCC was 85.7% in the induced cancer and vehicle groups while in rats treated with DCBME at 100, 500 and 1000 mg/kg was 57.1%, 28.6% and 14.3%, respectively.

CONCLUSIONS

(DCBME)-apoptosis induction reported in this work can be exploited as a potential antitumor agent with applications in medicinal treatments of tongue SCC.

Potential of Central, Eastern and Western Africa Medicinal Plants for Cancer Therapy: Spotlight on Resistant Cells and Molecular Targets

Cancer remains a major health hurdle worldwide and has moved from the third leading cause of death in the year 1990 to second place after cardiovascular disease since 2013. Chemotherapy is one of the most widely used treatment modes; however, its efficiency is limited due to the resistance of cancer cells to cytotoxic agents. The present overview deals with the potential of the flora of Central, Eastern and Western African (CEWA) regions as resource for anticancer drug discovery. It also reviews the molecular targets of phytochemicals of these plants such as ABC transporters, namely P-glycoprotein (P-gp), multi drug-resistance-related proteins (MRPs), breast cancer resistance protein (BCRP, ABCG2) as well as the epidermal growth factor receptor (EGFR/ErbB-1/HER1), human tumor suppressor protein p53, caspases, mitochondria, angiogenesis, and components of MAP kinase signaling pathways. Plants with the ability to preferentially kills resistant cancer cells were also reported. Data compiled in the present document were retrieved from scientific websites such as PubMed, Scopus, Sciencedirect, Web-of-Science, and Scholar Google. In summary, plant extracts from CEWA and isolated compounds thereof exert cytotoxic effects by several modes of action including caspases activation, alteration of mitochondrial membrane potential (MMP), induction of reactive oxygen species (ROS) in cancer cells and inhibition of angiogenesis. Ten strongest cytotoxic plants from CEWA recorded following in vitro screening assays are: Beilschmiedia acuta Kosterm, Echinops giganteus var. lelyi (C. D. Adams) A. Rich., Erythrina sigmoidea Hua (Fabaceae), Imperata cylindrical Beauv. var. koenigii Durand et Schinz, Nauclea pobeguinii (Pobég. ex Pellegr.) Merr. ex E.M.A., Piper capense L.f., Polyscias fulva (Hiern) Harms., Uapaca togoensis Pax., Vepris soyauxii Engl. and Xylopia aethiopica (Dunal) A. Rich. Prominent antiproliferative compounds include: isoquinoline alkaloid isotetrandrine (51), two benzophenones: guttiferone E (26) and isoxanthochymol (30), the isoflavonoid 6α-hydroxyphaseollidin (9), the naphthyl butenone guieranone A (25), two naphthoquinones: 2-acetylfuro-1,4-naphthoquinone (4) and plumbagin (37) and xanthone V1 (46). However, only few research activities in the African continent focus on cytotoxic drug discovery from botanicals. The present review is expected to stimulate further scientific efforts to better valorize the African flora.

Bovine lactoferricin P13 triggers ROS-mediated caspase-dependent apoptosis in SMMC7721 cells

Bovine lactoferricin P13 (LfcinB-P13) is a peptide derived from LfcinB. In the present study, the effect of LfcinB-P13 on the human liver cancer cell line SMMC7721 was investigated in vitro and in vivo. The results of the present study indicate that LfcinB-P13 significantly decreased SMMC7721 cell viability in vitro (P=0.032 vs. untreated cells), while exhibiting low cytotoxicity in the wild-type liver cell line L02. In addition, the rate of apoptosis in SMMC7721 cells was significantly increased following treatment with 40 and 60 µg/ml LfcinB-P13 (P=0.0053 vs. the control group), which was associated with an increase in the level of reactive oxygen species (ROS) and the activation of caspase-3 and -9. Furthermore, ROS chelation led to the suppression of LfcinB-P13-mediated caspase-3 and -9 activation in SMMC7721 cells. LfcinB-P13 was demonstrated to markedly inhibit tumor growth in an SMMC7721-xenograft nude mouse model. The results of the present study indicate that LfcinB-P13 is a novel candidate therapeutic agent for the treatment of liver cancer.

In vitro organo-protective effect of bark extracts from Syzygium guineense var macrocarpum against ferric-nitrilotriacetate-induced stress in wistar rats homogenates

Background

Overconsumption of oxygen in mammalian cells often lead to the production of reactive oxygen species (ROS) resulting from different mechanisms. Escape of scavenging enzymes/components or nutritional failure are the most important origins. Plant-derived molecules may protect biological molecules either by quenching free radicals, delaying or preventing the ROS formation or by restoring antioxidant enzymes activities. The present study assessed the antioxidant, phenolic profile and protective effect of barks extracts of Syzyguim guineense var macrocarpum against ferric nitriloacetate-induced stress in the liver, heart kidney and brain tissues of wistar rat homogenates.

Methods

Three extracts (aqueous, ethanol and aqueous-ethanol) from the barks of S. guineense var macrocarpum were used in this study. The spectrophotometric standardized methods were used to determine the free radical scavenging and antioxidant potential of the extracts. The protective properties of these plant extracts were also investigated as well as the quantification of secondary metabolites content (total phenolic, flavonoids and flavonols content). The HPLC method helped for characterizing phenolic compounds present in these extracts.

Results and Discussion

All the extracts exhibited a free radical scavenging potential in a concentration dependent manner which varied from 15.18 ± 0.80 to 97.15 ± 0.71 % depending to the type of extract and the method used. The ethanol extract had the higher phenolic content (432.85 mg QE/g extract), including total flavonoids (961.66 mg QE/g extract) and flavonols content (25.12 mg QE/g extract) and higher total antioxidant capacity. Among the phenolic compounds present in the extracts, the HLPC profile revealed the presence of syringic acid and apigenin in all the extracts. The extracts demonstrated their protective effect mostly in liver and brain homogenates by delaying or preventing lipid peroxidation, restoring enzymatic activities and enhancing glutathione levels.

Conclusion

The overall results demonstrated that the extracts exhibited significant antioxidant and protective effects in liver and brain liver homogenates.

Effect of cobalt(II) chloride hexahydrate on some human cancer cell lines

The present study investigates the anti-proliferative and apoptosis inducing mechanism of CoCl2·6H2O in PC-3 cancer cell line. Preliminary, three different forms of cobalt i.e., cobaltous (CoCl2·6H2O), macro-Co(II,III) oxide and nano-Co(II,III) oxide were screened for antiproliferative activity in PC-3 cell line. The CoCl2·6H2O being the most effective antiproliferative agent, hence it was further tested against lung (A549), prostrate (PC-3) and brain (IMR-32) cell lines. Human embryonic kidney cell line (293T) was used as a normal cell line to compare the toxicity of CoCl2·6H2O. The CoCl2·6H2O induced morphological and anatomical changes in PC-3 cancer cell which were studied using light, confocal and scanning electron microscopy. The lactate dehydrogenase was estimated which showed mild necrotic mode of cell death. The Annexin/PI staining confirmed the apoptotic mode of cell death in PC-3 cells. Further, production of reaction of reactive oxygen species and changes in mitochondrial membrane potential was also assessed spectrofluorimetrically. The cell cycle arrest was also investigated using flow cytometery. Finally, the caspase activity was estimated in CoCl2·6H2O treated PC-3 cancer cell line. Interestingly, it was found that CoCl2·6H2O induces more cell death in cancerous cells as compared to normal non-cancerous cells. These findings presented CoCl2·6H2O as potential antiproliferative agent.

CR-LAAO antileukemic effect against Bcr-Abl(+) cells is mediated by apoptosis and hydrogen peroxide

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by the presence of the Bcr-Abl tyrosine kinase protein, which confers resistance to apoptosis in leukemic cells. Tyrosine kinase inhibitors (TKIs) are effectively used to treat CML; however, CML patients in the advanced (CML-AP) and chronic (CML-CP) phases of the disease are usually resistant to TKI therapy. Thus, it is necessary to seek for novel agents to treat CML, such as the enzyme l-amino acid oxidase from Calloselasma rhodostoma (CR-LAAO) snake venom. We examined the antitumor effect of CR-LAAO in Bcr-Abl(+) cell lines and peripheral blood mononuclear cells (PBMC) from healthy subjects and CML patients. CR-LAAO was more cytotoxic towards Bcr-Abl(+) cell lines than towards healthy subjects' PBMC. The H2O2 produced during the enzymatic action of CR-LAAO mediated its cytotoxic effect. The CR-LAAO induced apoptosis in Bcr-Abl(+) cells, as detected by caspases 3, 8, and 9 activation, loss of mitochondrial membrane potential, and DNA damage. CR-LAAO elicited apoptosis in PBMC from CML-CP patients without TKI treatment more strongly than in PBMC from healthy subjects and TKI-treated CML-CP and CML-AP patients. The antitumor effect of CR-LAAO against Bcr-Abl(+) cells makes this toxin a promising candidate to CML therapy.

Antiproliferative activity and induction of apoptosis by Annona muricata (Annonaceae) extract on human cancer cells

Background

Annona muricata (A. muricata) is widely distributed in Asia, Africa and South America. Different parts of this plant are used to treat several diseases in Cameroon. The aim of this study is to determine the in vitro anti-proliferative effects and apoptotic events of A. muricata extracts on HL-60 cells as well as to quantify its phenols content.

Methods

The cell viability was measured by using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay while the changes in morphology of HL-60 cells, membrane mitochondrial potential (MMP) and the cell cycle were used for assessment apoptosis induction.

Results

The results show that the concentration of phenols, flavonoids and flavonols in the extracts varied depending on the part of the plant. All the extracts tested inhibited the proliferation of HL-60 cells in a concentration dependent manner with IC₅₀ varied from 6–49 μg/mL. The growth inhibition of the cells by extracts was associated with the disruption of MMP, reactive oxygen species (ROS) generation and the G0/G1 cell arrest.

Conclusion

These findings suggest that the extracts from A. muricata have strong antiproliferation potential and can induce apoptosis through loss of MMP and G0/G1 phase cell arrest.

Bioassay-guided isolation and identification of bioactive compound from aerial parts of Luffa acutangula against lung cancer cell line NCI-H460

Luffa acutangula (Cucurbitaceae) is widely used as a traditional medicine in India and was reported to possess various pharmacological activities including its anti-proliferative effects. In this study, the bioactive compound of ethanolic extract of L. acutangula (LA) was isolated using bioassay-guided approach. Five major fractions were collected and evaluated for their anti-proliferative activity against non-small cell lung cancer cells (NCI-H460). Among the test fractions, the fraction LA/FII effectively decreased the growth of cancer cells with IC50 values of 10 µg/ml concentration. Furthermore, it significantly increased intracellular reactive oxygen species and decreased the mitochondrial membrane potential. The apoptogenic activity of fraction LA/FII was confirmed by cell shrinkage, membrane blebbing and formation of apoptotic bodies. A single bioactive compound was isolated from the active faction, LA/FII and subsequently identified as 1,8 dihydroxy-4-methylanthracene 9,10-dione (compound 1) by comparing its spectral data [Ultraviolet (UV), Infrared (IR), Nuclear magnetic resonance (NMR) and Electrospray Ionization-Mass Spectroscopy (ESI-MS)] with literature values. This is the first report on the isolation of compound 1 from this plant.

Antineoplastic effects of Chlorella pyrenoidosa in the breast cancer model

OBJECTIVES

There has been considerable interest in both clinical and preclinical research about the role of phytochemicals in the reduction of risk for cancer in humans. The aim of this study was to determine the antineoplastic effects of Chlorella pyrenoidosa in experimental breast cancer in vivo and in vitro.

METHODS

In this experiment, the antineoplastic effects of C. pyrenoidosa in the chemoprevention of N-methyl-N-nitrosourea-induced mammary carcinogenesis in female rats were evaluated. Chlorella powder was administered through diet at concentrations of 0.3% and 3%. The experiment was terminated 14 wk after carcinogen administration. At autopsy, mammary tumors were removed and prepared for histopathological and immunohistochemical analysis. In vitro cytotoxicity assay, parameters of apoptosis, and proliferation after chlorella treatment in human breast adenocarcinoma (MCF-7) cells were carried out.

RESULTS

Basic parameters of experimental carcinogenesis, mechanism of action (biomarkers of apoptosis, proliferation, and angiogenesis), chosen metabolic variables, and side effects after long-term chlorella treatment in animals were assessed. Chlorella at higher concentration suppressed tumor frequency by 61% (P < 0.02) and lengthened tumor latency by 12.5 d (P < 0.02) in comparison with the controls. Immunohistochemical analysis of rat tumor cells showed caspase-7 expression increase by 73.5% (P < 0.001) and vascular endothelial growth factor receptor-2 expression decrease by 19% (P = 0.07) after chlorella treatment. In a parallel in vitro study, chlorella significantly decreased survival of MCF-7 cells in a dose-dependent manner. In chlorella-treated MCF-7 cells, a significant increase in cells having sub-G0/G1 DNA content and significant increase of early apoptotic and late apoptotic/necrotic cells after annexin V/PI staining assay were found. Decreases in mitochondrial membrane potential and increasing reactive oxygen species generation were observed in the chlorella-treated MCF-7 cells.

CONCLUSIONS

This study is the first report on the antineoplastic effects of C. pyrenoidosa in experimental breast cancer in vivo and in vitro.

Snake venom L-amino acid oxidases: an overview on their antitumor effects

The L-amino acid oxidases (LAAOs) constitute a major component of snake venoms and have been widely studied due to their widespread presence and various effects, such as apoptosis induction, cytotoxicity, induction and/or inhibition of platelet aggregation, hemorrhage, hemolysis, edema, as well as antimicrobial, antiparasitic and anti-HIV activities. The isolated and characterized snake venom LAAOs have become important research targets due to their potential biotechnological applications in pursuit for new drugs of interest in the scientific and medical fields. The current study discusses the antitumor effects of snake venom LAAOs described in the literature to date, highlighting the mechanisms of apoptosis induction proposed for this class of proteins.

The effect of Lfcin-B on non-small cell lung cancer H460 cells is mediated by inhibiting VEGF expression and inducing apoptosis

Lfcin-B, an antimicrobial peptide found in various exocrine secretions of mammals, showed antitumor effects. However, the effect and relative mechanism of Lfcin-B on non-small cell lung cancer is unclear. In this study, assay of cell viability, quantitative real-time PCR, Western blot, annexin V/propidium iodide assay, flow cytometry and tumor-xenograft model were applied to elucidate the mechanism of Lfcin-B on non-small cell lung cancer NCI-H460 (H460) cells. Lfcin-B significantly suppressed the proliferation of H460 cells in vitro. Additionally, the transcription and translation of the VEGF gene in H460 cells were restrained after exposure to Lfcin-B. Moreover, the apoptosis of H460 cells was induced by Lfcin-B through stimulating caspase-3, caspase-9 and preventing survivin expression on both the transcription and translation level. Meanwhile, Lfcin-B increased the production of reactive oxygen species and suppressed the RNA of antioxidant enzymes (GPX1, GPX2, SOD3 and catalase) in H460 cells. Finally, Lfcin-B significantly prevented the tumor growth in the H460-bearing mice model. These results indicated that Lfcin-B could be a potential candidate for the treatment of lung cancer.