Natural products for cancer chemotherapy

Identification and Characterization of a New Type III Polyketide Synthase from a Marine Yeast, Naganishia uzbekistanensis

A putative Type III Polyketide synthase (PKSIII) encoding gene was identified from a marine yeast, Naganishia uzbekistanensis strain Mo29 (UBOCC-A-208024) (formerly named as Cryptococcus sp.) isolated from deep-sea hydrothermal vents. This gene is part of a distinct phylogenetic branch compared to all known terrestrial fungal sequences. This new gene encodes a C-terminus extension of 74 amino acids compared to other known PKSIII proteins like Neurospora crassa. Full-length and reduced versions of this PKSIII were successfully cloned and overexpressed in a bacterial host, Escherichia coli BL21 (DE3). Both proteins showed the same activity, suggesting that additional amino acid residues at the C-terminus are probably not required for biochemical functions. We demonstrated by LC-ESI-MS/MS that these two recombinant PKSIII proteins could only produce tri- and tetraketide pyrones and alkylresorcinols using only long fatty acid chain from C8 to C16 acyl-CoAs as starter units, in presence of malonyl-CoA. In addition, we showed that some of these molecules exhibit cytotoxic activities against several cancer cell lines.

Predicting and Quantifying Antagonistic Effects of Natural Compounds Given with Chemotherapeutic Agents: Applications for High-Throughput Screening

Natural products have been used for centuries to treat various human ailments. In recent decades, multi-drug combinations that utilize natural products to synergistically enhance the therapeutic effects of cancer drugs have been identified and have shown success in improving treatment outcomes. While drug synergy research is a burgeoning field, there are disagreements on the definitions and mathematical parameters that prevent the standardization and proper usage of the terms synergy, antagonism, and additivity. This contributes to the relatively small amount of data on the antagonistic effects of natural products on cancer drugs that can diminish their therapeutic efficacy and prevent cancer regression. The ability of natural products to potentially degrade or reverse the molecular activity of cancer therapeutics represents an important but highly under-emphasized area of research that is often overlooked in both pre-clinical and clinical studies. This review aims to evaluate the body of work surrounding the antagonistic interactions between natural products and cancer therapeutics and highlight applications for high-throughput screening (HTS) and deep learning techniques for the identification of natural products that antagonize cancer drug efficacy.

Diadema setosum: isolation of bioactive secondary metabolites with cytotoxic activity toward human cervical cancer

In our promising project toward discovery of secondary metabolites with potential anticancer activity against human cervical cancer, seven marine organisms were screened for their cytotoxic activity against HeLa cancer cell line using MTT colorimetric assay. The crude extract of the outer shell of Diadema setosum showed promising activity with 88.02% inhibition at a concentration 250 µg/ml. Chromatographic investigation of the Ethyl acetate fraction, which is the main contributor to the activity (IC₅₀= 43.1 ± 5.94 µg/ml), led to isolation of five compounds. Structures of the isolates (1-5) were elucidated by 1 D and 2 D NMR spectroscopy and HR-ESI-MS analysis. 5α,8α-epidioxycholest-6-en-3β ol (2) and 5α,8α-epidioxycholest-6,9(11)-en-3β ol (3) showed the highest cytotoxic activity with IC₅₀ values 12.1 ± 2.74 µg/ml and 21.8 ± 6.32 µg/ml, respectively. Epidioxy steroids with cholestane nucleus could be a prospective candidate for the development of drugs for treatment of human cervical cancer.

Targeting castration-resistant prostate cancer with a novel RORγ antagonist elaiophylin

Prostate cancer (PCa) patients who progress to metastatic castration-resistant PCa (mCRPC) mostly have poor outcomes due to the lack of effective therapies. Our recent study established the orphan nuclear receptor RORγ as a novel therapeutic target for CRPC. Here, we reveal that elaiophylin (Elai), an antibiotic from Actinomycete streptomyces, is a novel RORγ antagonist and showed potent antitumor activity against CRPC in vitro and in vivo. We demonstrated that Elai selectively binded to RORγ protein and potently blocked RORγ transcriptional regulation activities. Structure–activity relationship studies showed that Elai occupied the binding pocket with several key interactions. Furthermore, Elai markedly reduced the recruitment of RORγ to its genomic DNA response element (RORE), suppressed the expression of RORγ target genes AR and AR variants, and significantly inhibited PCa cell growth. Importantly, Elai strongly suppressed tumor growth in both cell line based and patient-derived PCa xenograft models. Taken together, these results suggest that Elai is novel therapeutic RORγ inhibitor that can be used as a drug candidate for the treatment of human CRPC.

The pleiotropic role of transcription factor STAT3 in oncogenesis and its targeting through natural products for cancer prevention and therapy

Signal transducer and activator of transcription 3 (STAT3) is one of the crucial transcription factors, responsible for regulating cellular proliferation, cellular differentiation, migration, programmed cell death, inflammatory response, angiogenesis, and immune activation. In this review, we have discussed the classical regulation of STAT3 via diverse growth factors, cytokines, G-protein-coupled receptors, as well as toll-like receptors. We have also highlighted the potential role of noncoding RNAs in regulating STAT3 signaling. However, the deregulation of STAT3 signaling has been found to be associated with the initiation and progression of both solid and hematological malignancies. Additionally, hyperactivation of STAT3 signaling can maintain the cancer stem cell phenotype by modulating the tumor microenvironment, cellular metabolism, and immune responses to favor drug resistance and metastasis. Finally, we have also discussed several plausible ways to target oncogenic STAT3 signaling using various small molecules derived from natural products.

Polyphenols Extracted from Chinese Hickory (Carya cathayensis) Promote Apoptosis and Inhibit Proliferation through the p53-Dependent Intrinsic and HIF-1α-VEGF Pathways in Ovarian Cancer Cells

Ovarian cancer is the second most common gynecologic cancer with an estimated 13,940 mortalities across the United States in 2020. Natural polyphenols have been shown to double the survival time of some cancer patients due to their anticancer properties. Therefore, the effect of polyphenols extracted from Chinese hickory seed skin Carya cathayensis (CHSP) on ovarian cancer was investigated in the present study. Cell viability results showed that CHSP is more effective in inhibiting ovarian cancer cells than normal ovarian cells, with the IC50 value for inhibition of cell proliferation of Ovarian cancer cells (OVCAR-3) being 10.33 ± 0.166 μg/mL for a 24 h treatment. Flow cytometry results showed that the apoptosis rate was significantly increased to 44.21% after 24 h treatment with 20 μg/mL of CHSP. Western blot analysis showed that CHSP induced apoptosis of ovarian cancer cells through a p53-dependent intrinsic pathway. Compared with control values, levels of VEGF excreted by OVCAR-3 cancer cells were reduced to 7.87% with a 40 μg/mL CHSP treatment. Consistent with our previous reports, CHSP inhibits vascular endothelial growth factor (VEGF) secretion by regulating the HIF-1α-VEGF pathway. In addition, we also found that the inhibitory effect of CHSP on ovarian cancer is related to the up-regulation of Phosphatase and tension homolog (PTEN) and down-regulation of nuclear factor kappa-B (NF-kappa B). These findings provide some evidence of the anti-ovarian cancer properties of CHSP and support the polyphenols as potential candidates for ovarian cancer adjuvant therapy.

Flavonoid-rich extracts from okra flowers exert antitumor activity in colorectal cancer through induction of mitochondrial dysfunction-associated apoptosis, senescence and autophagy

Okra flowers contain a higher content of total flavonoids than most other flowers; however little research has been conducted on their potential benefits, including antitumor activity. In this study, we extracted and purified flavonoids from okra flower (AFE), and aimed to evaluate the effect of AFE and its underlying mechanism on colorectal cancer (CRC) cell growth in vitro and in vivo. Here, we identify that AFE is a safe, natural antioxidant and exerts significant antitumor efficacy on the inhibition of CRC cell proliferation and metastasis as well as tumour growth in vivo. We further reveal that AFE inhibits CRC cell proliferation by inducing mitochondrial dysfunction, which results from the activation of p53 and induction of apoptosis and senescence, and inhibits autophagic degradation. Furthermore, AFE inhibited migration and invasion of CRC cells by regulating the balance of MMP2/TIMP2 and MMP9 expression levels. Of note, administration of AFE as a preventive agent achieves a more effective antitumor effect than the therapeutic agent in a xenograft mouse model. Our results reveal, for the first time, that AFE is a safe, natural antioxidant with significant antitumor efficacy, which has great potential in the application for CRC prevention and treatment.

A Prelude to Biogermylene Chemistry*

The biological applications of germylenes remain unrealised owing to their unstable nature. We report the isolation of air-, water-, and culture-medium-stable germylene DPMGeOH (3; DPM=dipyrromethene ligand) and its potential biological application. Compound 3 exhibits antiproliferative effects comparable to that of cisplatin in human cancer cells. The cytotoxicity of compound 3 on normal epithelial cells is minimal and is similar to that of the currently used anticancer drugs. These findings provide a framework for a plethora of biological studies using germylenes and have important implications for low-valent main-group chemistry.

Anticancer activity of Neptunia oleracea methanolic extracts

Neptunia oleracea Lour (water mimosa) is an edible medicinal plant used in treating various diseases. According to Phytochemical and Ethnobotanical Databases, Neptunia oleracea Lour is used in curing earaches, dysentery, syphilis, and tumour. The present study was aimed at demonstrating the anticancer activity of the Neptunia oleracea Lour methanolic extract. The methanolic extract was isolated and its anti-proliferative activity was studied on haematological cancer cell lines. The activity of the extract was further evaluated using cell cycle analysis and apoptosis assays. In addition to this, effect of the extract on c-Myc and PErk1/2 modulation was also evaluated. Neptunia oleracea Lour extract induced cell death in cancer cells while sparing normal cells. An increase in cleaved PARP and reduction in BCL-2 levels observed upon treatment. Neptunia oleracea causes reduction in c-Myc levels and pERK1/2 protein levels. Thus, our work highlights the methanolic extract of Neptunia oleracea Lour as a promising anti-cancer agent.

Design, synthesis and biological activity of 1,4-quinone moiety attached to betulin derivatives as potent DT-diaphorase substrate

In this research, betulin derivatives were bonded to the 1,4-quinone fragment by triazole linker. Furthermore, the enzymatic assay used has shown that these compounds are a good DT-diaphorase (NQO1) substrates as evidenced by increasing enzymatic conversion rates relative to that of streptonigrin. The anticancer activities of the hybrids were tested against a panel of human cell lines, like: melanoma, ovarian, breast, colon, and lung cancers. The structure-activity relationship showed that the activity depends on the type of 1,4-quinone moiety and the tumor cell lines used. It was also found that the anticancer effects were increasing against the cell line with higher NQO1 protein level, like: breast (T47D, MCF-7), colon (Caco-2), and lung (A549) cancers. The transcriptional activity of the gene encoding a proliferation marker (H3 histone), cell cycle regulators (p53 and p21) and apoptosis pathway (BCL-2 and BAX) for selected compounds were determined. The molecular docking study was carried out to examine the interaction between the hybrids and NQO1 enzyme. The computational simulation showed that the type of the 1,4-quinone moiety influences location of the compound in the active site of the enzyme. It is worth noting that the study of new hybrids of betulin as substrate for NQO1 protein may lead to new medical therapeutic applications in the future.

Anticancer Drug Discovery from Microbial Sources: The Unique Mangrove Streptomycetes

Worldwide cancer incidence and mortality have always been a concern to the community. The cancer mortality rate has generally declined over the years; however, there is still an increased mortality rate in poorer countries that receives considerable attention from healthcare professionals. This suggested the importance of the prompt detection, effective treatment, and prevention strategies. The genus Streptomyces has been documented as a prolific producer of biologically active secondary metabolites. Streptomycetes from mangrove environments attract researchers' attention due to their ability to synthesize diverse, interesting bioactive metabolites. The present review highlights research on mangrove-derived streptomycetes and the production of anticancer-related compounds from these microorganisms. Research studies conducted between 2008 and 2019, specifically mentioning the isolation of streptomycetes from mangrove areas and described the successful purification of compound(s) or generation of crude extracts with cytotoxic activity against human cancer cell lines, were compiled in this review. It is anticipated that there will be an increase in prospects for mangrove-derived streptomycetes as one of the natural resources for the isolation of chemotherapeutic agents.

Antiproliferative Effects of Alkaloids from the Bulbs of Crinum abyscinicum Hochst. ExA. Rich

Crinum abyscinicum Hochst. ExA. Rich bulb is traditionally used in Ethiopia for the treatment of various ailments including internal parasites, mastitis, rabies, colic diseases of animals, and cancer. Despite its importance in traditional cancer treatment, no research work has been reported on the antiproliferative activity of the bulb extract and its major constituents. Phytochemical investigation of the bulb extract of C. abyscinicum by PTLC over silica gel resulted in the isolation of two alkaloids, which were unequivocally identified as 6-hydroxycrinamine and lycorine on the basis of ¹H- and ¹³C-NMR and MS analysis. The bulb extract, 6-hydroxycrinamine, and lycorine possessed significant antiproliferative activity, lycorine being the most active exhibiting GI₅₀ values of 2.8 μg/ml and 3.4 μg/ml against A2780 and MV4-11 cells, respectively. Cell cycle analysis and annexin V/propidium iodide double staining in A2780 cells revealed that both compounds increased the percentage of cells in the S-phase at 30 μg/ml without inducing apoptosis. Our results suggest that the antiproliferative activities of the bulb extract of C. abyscinicum, 6-hydroxycrinamine, and lycorine could support the traditional claim of the plant against cancer.

Curcumin against Prostate Cancer: Current Evidence

Cancer is a condition characterized by remarkably enhanced rates of cell proliferation paired with evasion of cell death. These deregulated cellular processes take place following genetic mutations leading to the activation of oncogenes, the loss of tumor suppressor genes, and the disruption of key signaling pathways that control and promote homeostasis. Plant extracts and plant-derived compounds have historically been utilized as medicinal remedies in different cultures due to their anti-inflammatory, antioxidant, and antimicrobial properties. Many chemotherapeutic agents used in the treatment of cancer are derived from plants, and the scientific interest in discovering plant-derived chemicals with anticancer potential continues today. Curcumin, a turmeric-derived polyphenol, has been reported to possess antiproliferative and proapoptotic properties. In the present review, we summarize all the in vitro and in vivo studies examining the effects of curcumin in prostate cancer.

Uptake of silver, gold, and hybrids silver-iron, gold-iron and silver-gold aminolevulinic acid nanoparticles by MCF-7 breast cancer cells

BACKGROUND

Nanoparticles show promise for theranostic applications in cancer. The metal-based nanoparticles can be used both as photosensitizers and delivery vehicles. In bimetallic particles based on gold or silver and iron, a combination of the plasmonic features of the gold or silver components with the magnetic properties of the iron makes these hybrid nanomaterials suitable for both imaging and therapeutic applications. Herein, we discuss toxicity and cell internalization of metallic (silver and gold) and bimetallic (silver-iron, gold-iron, and silver-gold) aminolevulinic acid (ALA) nanoparticles. ALA can control the production of an intracellular photosensitizer, protoporphyrin IX (PpIX), commonly used in photodynamic therapy.

METHODS

Nanoparticles were synthesized by photoreduction method and characterized by UV/Vis spectra, Zeta potential, FTIR, XRD, and transmission electron microscopy. The amount of singlet oxygen generation by a yellow LED, and ultrasound was studied for gold, gold-iron, and silver-gold nanoparticles. Cytotoxicity assays of MCF-7 in the presence of nanoparticles were performed, and PpIX fluorescence was quantified by high content screening (HCS).

RESULTS

Red fluorescence observed after 24 h of nanoparticles incubation on MCF-7 cells, indicated that the ALA in surface of nanoparticles was efficiently converted to PpIX. The best results for singlet oxygen generation with LED or ultrasound irradiation were obtained with ALA:AgAuNPs.

CONCLUSIONS

The studied nanoparticles present the potential to deliver aminolevulinic acid to breast cancer cells efficiently, generate singlet oxygen, and convert ALA into PpIX inside the cells allowing photodiagnosis and therapies such as photodynamic and sonodynamic therapies.

Stimulation of calcium influx and CK1α by NF-κB antagonist [6]-Gingerol reprograms red blood cell longevity

Chemotherapy-induced anemia (CIA) is a major obstacle in cancer management. Although the mechanisms governing CIA are poorly understood, recent efforts have identified suicidal erythrocyte (red blood cell, RBC) death as a possible cause of CIA. [6]-Gingerol (GNG), a polyphenol extracted from Zingiber officinale plant, exhibits a wide array of biological activities including antimicrobial, antioxidant, anti-inflammatory, immunomodulatory, and anticancer activities, in vitro and in vivo. However, the potential toxicity of GNG to human RBCs remains unexplored. RBCs from heparinized blood were isolated by centrifugation and exposed to antitumor concentrations (10-100 µM) of GNG for 24 hr at 37°C. Hemolysis was calculated from hemoglobin leakage in the supernatant (λ_max  = 405 nm), while cytofluorometric analysis of eryptosis employed Annexin-V-FITC to detect phosphatidylserine (PS) exposure, forward scatter (FSC) to estimate cell volume, Fluo4/AM to measure calcium activity, and H₂ DCFDA to assess oxidative stress. Moreover, zVAD(OMe)-FMK, SB203580, necrostatin-2, staurosporin, and D4476 were used to identify signaling pathways responsive to GNG. GNG induced significant hemolysis at 100 µM, independently of extracellular calcium, and increased Annexin-V-FITC fluorescence that was thoroughly abrogated without extracellular calcium. GNG also enhanced Fluo4 fluorescence and reduced FSC, but had no significant effect on DCF fluorescence. Importantly, the presence of D4476 significantly attenuated GNG-induced hemolysis. In conclusion, GNG stimulates premature RBC death characterized by loss of membrane asymmetry, elevated cytosolic calcium, cell shrinkage, and casein kinase 1α activation. Blocking the activity of calcium channels or CK1α may, therefore, ameliorate the toxic effects of GNG on RBCs. PRACTICAL APPLICATIONS: This report presents a safety assessment of GNG as a chemotherapeutic agent and highlights the novel toxicity of GNG to human RBCs. Our findings provide novel insights that may lead to more efficient utilization of GNG in chemotherapy. Specifically, our data revealed the involvement of calcium channels and casein kinase 1α in mediating GNG-induced premature RBC death, and, therefore, inverse agonists or inhibitors of either pathway may be used as pharmaceutical adjuvants to attenuate the toxic effects of GNG.

Hispolon: A natural polyphenol and emerging cancer killer by multiple cellular signaling pathways

Nature as an infinite treasure of chemotypes and pharmacophores will continue to play an imperative role in the drug discovery. Natural products (NPs) such as plant and fungal metabolites have emerged as leads in drug discovery during recent years due to their efficacy, safety and selectivity. The current review summarizes natural sources as well as pharmacological potential of hispolon which is a major constituent of traditional medicinal mushroom Phellinus linteus. The study aims to update the scientific community about recent developments of hispolon in the arena of natural drugs by providing insights into its present status in therapeutic pursuits. Hispolon, a polyphenol has been reported to possess anticancer, antidiabetic, antioxidant, antiviral and anti-inflammatory activities. It fights against cancer via induction of apoptosis, halting cell cycle and inhibition of metastasis by targeting various cellular signaling pathways including PI3K/Akt, MAPK and NF-κB. The current review proposes that hispolon provides a novel opportunity for pharmacological applications and its styrylpyrone carbon skeleton might serve as an attractive scaffold for drug development. However, future researches are recommended to assess bioavailability, toxicological limits, pharmacokinetic and pharmacodynamic profiles of hispolon, in order to establish its potential as a potent multi-targeted drug in the near future.

The impact of curcumin-graphene based nanoformulation on cellular interaction and redox-activated apoptosis: An in vitro colon cancer study

Natural plants derivatives have gained enormous merits in cancer therapy applications upon formulation with nanomaterials. Curcumin, as a popular research focus has acquired such improvements surpassing its disadvantageous low bioavailability. To this point, the available research data had confirmed the importance of nanomaterial type in orienting cellular response and provoking different toxicological and death mechanisms that may range from physical membrane damage to intracellular changes. This in turn underlines the poorly studied field of nanoformulation interaction with cells as the key determinant in toxicology outcomes. In this work, curcumin-AuNPs-reduced graphene oxide nanocomposite (CAG) was implemented as a model, to study the impact on cellular membrane integrity and the possible redox changes using colon cancer in vitro cell lines (HT-29 and SW-948), representing drug-responsive and resistant subtypes. Morphological and biochemical methods of transmission electron microscopy (TEM), apoptosis assay, reactive oxygen species (ROS) and antioxidants glutathione and superoxide dismutase (GSH and SOD) levels were examined with consideration to suitable protocols and vital optimizations. TEM micrographs proved endocytic uptake with succeeding cytoplasm deposition, which unlike other nanomaterials studied previously, conserved membrane integrity allowing intracellular cytotoxic mechanism. Apoptosis was confirmed with gold-standard morphological features observed in micrographs, while redox parameters revealed a time-dependent increase in ROS accompanied with regressive GSH and SOD levels. Collectively, this work demonstrates the success of graphene as a platform for curcumin intracellular delivery and cytotoxicity, and further highlights the importance of suitable in vitro methods to be used for nanomaterial validation.

Mothers’ Attitudes toward the Use of Complementary and Alternative Medicine in Children with Cancer

Background: Children who have cancer suffer from a wide range of symptoms and side-effects of disease and treatment, and such conditions have harmful effects on the quality of life of a child and family. So, the families of such children turn to complementary and alternative medicine treatments for children with cancer. Objectives: Therefore, this study aimed at determining the mothers’ attitudes toward the use of complementary and alternative medicine in children with cancer. Methods: This cross-sectional research was conducted from January 2018 to January 2019 in the oncology section of Yazd Shahid Sadooghi Hospital in a nonrandom and convenience sampling method on 150 mothers of children with cancer. The instruments of data collection include demographic information questionnaires and a 6-part questionnaire to evaluate mothers’ performance. To investigate the face and content validity of the questionnaire, the opinions of 10 experts were considered, and to investigate the reliability of the questionnaire, the test-retest method was used, and the intraclass correlation coefficient (ICC) was reportedly 0.80. After completing the questionnaires, the collected data were analyzed, using SPSS 23 by utilizing descriptive statistics, including mean, standard deviation (SD), frequency, and percent. Results: Overall, 83.34% of mothers mentioned praying as a way of complementary and alternative medicine, 67.34% used complementary and alternative medicine to increase child recovery chance, 74% reported general child recovery, 20% reported the occurrence of side-effects following the use of complementary and alternative medicine, 67.33% introduced their friends as their information source, 33.6% avoided informing the physician regarding the use of complementary and alternative medicine, and 76% maintained that due to the objection of physicians, they avoided informing him/her. Conclusions: The use of complementary and alternative medicine is common among mothers but due to the occurrence of side-effects, using invalid information sources and hiding it from a physician, the oncologists must provide a suitable opportunity for asking and answering to guide mothers for correct performance in the use of complementary and alternative medicine.

1-Cinnamoyltrichilinin from Melia azedarach Causes Apoptosis through the p38 MAPK Pathway in HL-60 Human Leukemia Cells

Acute myeloid leukemia (AML) is an aggressive type of human leukemia with a low survival rate, and its complete remission remains challenging. Although chemotherapy is the first-line treatment of AML, it exerts toxicity in noncancerous cells when used in high doses, thus necessitating the development of novel compounds with a high therapeutic window. This study aimed to investigate the anticancer effects of several compounds derived from the fruits of Melia azedarach (a tree with medicinal properties). Among them, 1-cinnamoyltrichilinin (CT) was found to strongly suppress the viability of HL-60 human leukemia cells. CT treatment induced apoptosis and increased nuclear fragmentation and fractional DNA content in HL-60 cells in a dose-dependent manner. CT induced phosphorylation of p38 mitogen-activated protein kinases (p38), though not of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK), and activated Bcl-2 family proteins towards the proapoptosis and cleavage of caspase-3 and poly (ADP-ribose) polymerase. Both CT-mediated apoptosis and apoptotic protein expression were reversed by treatment with the p38 inhibitor, thereby indicating the p38 pathway to be critical in CT-stimulated apoptosis. The results collectively indicated CT to suppress HL-60 survival by activating the p38 pathway and inducing apoptosis, hence being a novel potential therapeutic agent for AML.

Drug Delivery Systems of Natural Products in Oncology

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

Rosemary (Rosmarinus officinalis L.) extract inhibits prostate cancer cell proliferation and survival by targeting Akt and mTOR

Prostate cancer is the most commonly diagnosed type of cancer in North American men and is typically classified as either androgen receptor positive or negative depending on the expression of the androgen receptor (AR). AR positive prostate cancer can be treated with hormone therapy while AR negative prostate cancer is aggressive and does not respond to hormone therapy. It has been previously reported that rosemary extract (RE) has antioxidant, anti-inflammatory and anti-cancer properties. In the present study, we found that treatment of the androgen-insensitive PC-3 prostate cancer cells with RE resulted in a significant inhibition of proliferation, survival, migration, Akt, and mTOR signaling. In addition, treatment of the androgen-sensitive 22RV1 prostate cancer cells with RE resulted in a significant inhibition of proliferation and survival while RE had no effect on normal prostate epithelial PNT1A cells. These findings suggest that RE has potent effects against prostate cancer and warrants further investigation.

Osthole extracted from a citrus fruit that affects apoptosis on A549 cell line by histone deacetylasese inhibition (HDACs)

This study aims to investigate the interactions between osthole extracted from Egyptian citrus fruits as HDACs inhibitor by theoretical study and practically. Besides, osthole was assed as anti-cancer activity. In this study, osthole was extracted from the Egyptian citrus fruit and was characterized. The role of osthole as in vitro inhibitor of HDACs was estimated and evaluated the antitumor activity against human lung cancer cells (A549), Caspase-9 activity was detected. The results obtained from GC-MS indicate that the grapefruit showed the highest osthole concentration compared to the other citrus fruits. Moreover, the grapefruit osthole competitively inhibits HDACs. The inhibition constant value, (Ki=3.36 mM), indicates that osthole exerts an inhibitory effect upon HDACs activity. In vitro study of osthole could inhibit the growth of A549 cells that depend on time and concentration. It also induces apoptosis and causes an increase of caspase-9 by osthole. In conclusion, grapefruit osthole could induce the apoptosis in A549 lung cancer cells by inhibiting the histone deacetylase.

Marine Cyanobacteria and Microalgae Metabolites-A Rich Source of Potential Anticancer Drugs

Cancer is at present one of the utmost deadly diseases worldwide. Past efforts in cancer research have focused on natural medicinal products. Over the past decades, a great deal of initiatives was invested towards isolating and identifying new marine metabolites via pharmaceutical companies, and research institutions in general. Secondary marine metabolites are looked at as a favorable source of potentially new pharmaceutically active compounds, having a vast structural diversity and diverse biological activities; therefore, this is an astonishing source of potentially new anticancer therapy. This review contains an extensive critical discussion on the potential of marine microbial compounds and marine microalgae metabolites as anticancer drugs, highlighting their chemical structure and exploring the underlying mechanisms of action. Current limitation, challenges, and future research pathways were also presented.

Targeting X chromosome-linked inhibitor of apoptosis protein in mucoepidermoid carcinoma of the head and neck: A novel therapeutic strategy using nitidine chloride

Nitidine chloride (NC) was recently reported to exhibit a wide range of pharmacological properties for several diseases, including cancer. Here we report for the first time that NC is a potential therapeutic agent for mucoepidermoid carcinoma (MEC) occurring in the head and neck because it suppresses X chromosome-linked inhibitor of apoptosis protein (XIAP) in human MEC in vitro and in vivo. The antitumor effects of NC were evaluated by trypan blue exclusion assay, western blotting, live/dead assay, 4',6-diamidino-2-phenylindole (DAPI) staining, human apoptosis antibody array, immunofluorescence staining, immunohistochemistry, small interfering RNA assay, transient transfection of XIAP overexpression vector, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and histopathological examination of organs. NC inhibited cell viability and induced caspase-dependent apoptosis in vitro. A human apoptosis antibody array assay showed that XIAP is suppressed by NC treatment. XIAP was overexpressed in oral squamous cell carcinoma (OSCC) tissues that arose from the head and neck, and high XIAP expression was correlated with poor prognosis in OSCC patients. XIAP depletion significantly increased apoptosis, and ectopic XIAP overexpression attenuated the apoptosis induced by NC treatment. NC suppressed tumor growth in vivo at a dosage of 5 mg/kg/day. The number of TUNEL-positive cells increased and the protein expression of XIAP was consistently downregulated in NC-treated tumor tissues. In addition, NC caused no histopathological changes in the liver or kidney. These findings provide new insights into the mechanism of action underlying the anticancer effects of NC and demonstrate that NC is a promising therapeutic agent for the treatment of human MEC of the head and neck. KEY MESSAGES: • Nitidine chloride induces caspase-dependent apoptosis in MEC of the head and neck. • High XIAP expression correlates with poor prognosis of OSCC patients. • Nitidine chloride suppresses tumor growth in vivo without any systemic toxicities. • Targeting XIAP is a novel chemotherapeutic strategy for MEC of the head and neck.

Increased Cytotoxic Efficacy of Protocatechuic Acid in A549 Human Lung Cancer Delivered via Hydrophobically Modified-Chitosan Nanoparticles As an Anticancer Modality

The growing incidence of global lung cancer cases against successful treatment modalities has increased the demand for the development of innovative strategies to complement conventional chemotherapy, radiation, and surgery. The substitution of chemotherapeutics by naturally occurring phenolic compounds has been touted as a promising research endeavor, as they sideline the side effects of current chemotherapy drugs. However, the therapeutic efficacy of these compounds is conventionally lower than that of chemotherapeutic agents due to their lower solubility and consequently poor intracellular uptake. Therefore, we report herein a hydrophobically modified chitosan nanoparticle (pCNP) system for the encapsulation of protocatechuic acid (PCA), a naturally occurring but poorly soluble phenolic compound, for increased efficacy and improved intracellular uptake in A549 lung cancer cells. The pCNP system was modified by the inclusion of a palmitoyl group and physico-chemically characterized to assess its particle size, Polydispersity Index (PDI) value, amine group quantification, functional group profiling, and morphological properties. The inclusion of hydrophobic palmitoyl in pCNP-PCA was found to increase the encapsulation of PCA by 54.5% compared to unmodified CNP-PCA samples whilst it only conferred a 23.4% larger particle size. The single-spherical like particles with uniformed dispersity pCNP-PCA exhibited IR bands, suggesting the successful incorporation of PCA within its core, and a hydrophobic layer was elucidated via electron micrographs. The cytotoxic efficacy was then assessed by using an MTT cytotoxicity assay towards A549 human lung cancer cell line and was compared with traditional chitosan nanoparticle system. Fascinatingly, a controlled release delivery and enhanced therapeutic efficacy were observed in pCNP-PCA compared to CNP, which is ascribed to lower IC50 values in the 72-h treatment in the pCNP system. Using the hydrophobic system, efficacy of PCA was significantly increased in 24-, 48-, and 72-h treatments compared to a single administration of the compound, and via the unmodified CNP system. Findings arising from this study exhibit the potential of using such modified nanoparticulate systems in increasing the efficacy of natural phenolic compounds by augmenting their delivery potential for better anti-cancer responses.

Curcumin-silica nanocomplex preparation, hemoglobin and DNA interaction and photocytotoxicity against melanoma cancer cells

Melanoma is a malignant cancer of the skin associated with a high mortality. Early medical diagnosis and surgical intervention are essential for the treatment of melanoma. The use of plant-based compounds is an important strategy for the prevention and treatment of different types of cancers. Curcumin is a promising natural anticancer compound used towards treatment for various kinds of cancers. Studies have shown that curcumin could be applied as a photosensitizer in cancer photodynamic therapy (PDT). PDT uses light and a photosensitizing agent which produce reactive oxygen species leading to cancer cell death. The main obstacle for using curcumin as photosensitizer is its low solubilization ability in an aqueous environment. To improve its application in cancer treatment, we synthetized curcumin-silica nanoparticles as photosensitizer for photodynamic treatment of human melanoma cancer cells. Scanning electron microscopy, Transmission electron microscopy, Powder X-ray diffraction and Thermo geometric analysis indicated that curcumin was loaded on silica. The solubility of curcumin in water increased by using silica nanoparticles which wasconfirmed by spectroscopy results. The spectroscopy study confirmed the interaction of curcumin-silica nanocomplex with double strand DNA and no interaction with hemoglobin. The curcumin-silica nanocomplex and curcumin photodynamic effect was investigated on human melanoma cancer cells (A375) and also human fibroblast cells. The cell toxicity experiments showed that the curcumin-silica nanocomplex had greater photodynamic effects on cancer cell death as compared to free curcumin. The apoptotic assay by acridine orange/ethidium bromide (AO/EB) dual staining and colony forming ability confirmed the MTT results. Therefore, these results suggest that the curcumin-silica nanocomplex has great potential to be employed in photodynamic treatment of melanoma cancer.

Combination of Curcumin and Metformin Inhibits Cell Growth and Induces Apoptosis without Affecting the Cell Cycle in LNCaP Prostate Cancer Cell Line

Side effects and chemotherapy resistance, demand new therapeutics with minimal side effects. Here, we investigated the combined effect of curcumin and metformin on the LNCaP prostate cancer cell line. LNCaP cells were treated with curcumin, metformin, and their combination at different concentrations. Cell viability was assessed by MTT assay and expression of Bax, Bcl-2, mTOR, hTERT, PUMA, p53 and p21 genes was analyzed by real-time PCR. Apoptosis and cell cycle were assessed by flow cytometry. Our results revealed that the viability of cells treated with curcumin, metformin, and their combination was significantly (P < 0.05) reduced with increasing the concentration and prolonging the treatment time. Meanwhile, the combination showed a synergistic effect within 48 h. In the curcumin treated group, the expression of Bcl-2 and hTERT genes diminished. In the metformin treated group, the expression of Bax and PUMA genes was enhanced while the expression of Bcl-2, hTERT, mTOR, and p53 genes declined. Although all treatments induced apoptosis, the combination of curcumin and metformin showed the maximum level of apoptosis, cytotoxicity, and expression of Bax gene. The combination of curcumin and metformin showed synergistic effects within 48 h. This combination could be a potential therapeutic candidate for prostate cancer to be further investigated.

Anticancer fungal natural products: Mechanisms of action and biosynthesis

Many fungal metabolites show promising anticancer properties both in vitro and in animal models, and some synthetic analogs of those metabolites have progressed into clinical trials. However, currently, there are still no fungi-derived agents approved as anticancer drugs. Two potential reasons could be envisioned: 1) lacking a clear understanding of their anticancer mechanism of action, 2) unable to supply enough materials to support the preclinical and clinic developments. In this review, we will summarize recent efforts on elucidating the anticancer mechanisms and biosynthetic pathways of several promising anticancer fungal natural products.

FB-15 inhibits MGC-803 cells growth by regulating energy metabolism

In this study, we scrutinized the anticancer effects of FB-15 on human gastric carcinoma MGC-803 cells in vitro and vivo, and its preliminary effect on tubulin and HIF-1α. We confirmed that FB-15 not only inhibited the proliferation of a large number of cells in a concentration and time-dependent manner but also inhibited proliferation of a single cell to form clones. FB-15 manifested little cytotoxicity for normal stomach cells GES-1. The flow cytometry analysis displayed that FB-15 induced apoptosis MGC-803 cells and mainly arrested cells in the S phase in a concentration-dependent manner. The results of the wound healing assay indicated that FB-15 suppressed cell migration. Furthermore, the western blotting showed that FB-15 down-regulated the expression of β3-tubulin and HIF-1α, consistent with Immunohistochemical assay. The binding modes of FB-15 with tubulin were clarified by molecular docking. FB-15 significantly suppressed the growth of MGC-803 gastric cancer tumors. The inhibitory effect of FB-15 on tumor growth was superior to 5-Fu. Taken together, these results provided evidence for FB-15 to be used as an effective anticancer drug candidate for gastric cancer.

Structure-Activity Relationships and Potent Cytotoxic Activities of Terphenyllin Derivatives from a Small Compound Library

A small library of 120 compounds was established with seventy new alkylated derivatives of the natural product terphenyllin, together with 45 previous reported derivatives and four natural p-terphenyl analogs. The 70 new derivatives were semi-synthesized and evaluated for cytotoxic activities against four cancer cell lines. Interestingly, 2',4''-diethoxyterphenyllin, 2',4,4''-triisopropoxyterphenyllin, and 2',4''-bis(cyclopentyloxy)terphenyllin showed potent activities with IC₅₀ values in a range from 0.13 to 5.51 μM, which were similar to those of the positive control, adriamycin. The preliminary structure-activity relationships indicated that the introduction of alkyl substituents including ethyl, allyl, propargyl, isopropyl, bromopropyl, isopentenyl, cyclopropylmethyl, and cyclopentylmethyl are important for improving the cytotoxicity.

Suppressive activities of mangiferin on human epithelial ovarian cancer

BACKGROUND

Epithelial carcinoma is a subtype of ovarian cancers, with the highest lethality among all ovarian cancer subtypes. Hitherto surgical excision combined with chemotherapy has been the most extensively employed method in clinical treatment. However, the disease relapses very frequently, calling for more effective therapies. Mangiferin, a natural xanthone glucoside, has displayed promising anti-cancer activities by in vitro studies, but its therapeutic value in epithelial ovarian cancer treatment, either by in vivo or in vitro studies, remained to be known.

PURPOSE

This study aimed to determine the suppressive activities of mangiferin on human epithelial ovarian cancer and elucidate the underlying molecular mechanisms.

STUDY DESIGN AND METHODS

We employed the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the crystal violet assay to determine the half maximal inhibitory concentration (IC50) values of mangiferin with paclitaxel as a positive control and the inhibitory effects of mangiferin on the proliferation of two human epithelial ovarian cancer cell lines. Wound healing and Transwell assays were used to determine anti-metastastic activities of mangiferin. ES-2 xenograft nude mouse model was used for the in vivo experiments. Western blotting, enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) assays were carried out for evaluating the expression level of matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9).

RESULTS

In the present study, we demonstrated by both in vitro and in vivo assays that mangiferin suppressed the progress of epithelial ovarian cancer in a dose-dependent manner. In the animals treated with mangiferin, the tumor volume and weight were reduced significantly. Analyses of involved molecular events demonstrated that mangiferin down-regulated the expression of metastasis-associated proteins MMP2 and MMP9.

CONCLUSION

Mangiferin strongly inhibited the progression of human epithelial ovarian cancer by down-regulating MMP2 and MMP9.

Bioinformatics and experimental studies of anti-leukemic activity from 6-gingerol demonstrate its role in p53 mediated apoptosis pathway

6-gingerol is a traditional medicine that possesses anti-cancer activity against several types of cancer. However, the mechanism of action still remains unclear. Therefore, this study explored the effects of 6-gingerol on anti-leukemic mechanisms in NB4, MOLT4, and Raji leukemic cell. Results indicated that 6-gingerol inhibited cell proliferation and induced cell apoptosis in these 3 cell lines. Moreover, 6-gingerol was shown to increase the mRNA expression of the caspase family thereby suggesting that 6-gingerol induced apoptosis through the caspase-dependent pathway. To explore the signaling pathway regulating 6-gingerol induced apoptosis, we utilized and integrated the network pharmacology approach together with experimental investigations. Targets of 6-gingerol were identified from ChEMBL and STITCH databases, which were used for constructing the protein-protein interaction (PPI) network. Results from the PPI network indicated that p53 was a key regulator. Moreover, it was found that 6-gingerol could increase the levels of p53 mRNA in all leukemic cell lines. Thus, 6-gingerol has shown to have anti-cancer activity. In addition, p53, BAX and BCL2 could be involved in the apoptosis pathway of these leukemic cells. This study is anticipated to be useful for the development of 6-gingerol as an anti-leukemic drug in the future.

Inhibition of autophagy sensitizes lignan-induced endoplasmic reticulum stress-mediated cell death

Relationship between autophagy and endoplasmic reticulum (ER) stress and their application to treat cancer have been actively studied these days. Recently, a lignan [(-)-(2R, 3R)-1,4-O-diferuloylsecoisolariciresinol, DFS] from Alnus japonica has been found to reduce the viability of colon cancer cells. In this study, we have observed DFS-induced autophagy in a variety of cancer cell lines. In addition, DFS led to ER stress, based on the activation of unfolded protein response (UPR) transducers and an elevated expression of UPR target genes in prostate and colon cancer cells. Further investigation has shown that DFS triggered the activation of AMP-activated protein kinase (AMPK) signaling and nuclear translocation of transcription factor EB (TFEB). Furthermore, the cytotoxicity of DFS was potentiated by the co-treatment of autophagy inhibitor in these cancer cells. This study has provided a noble implication that the combination of DFS and autophagy inhibition exerts a synergistic effect in cancer treatment.

Anticancer effects of a traditional Thai herbal recipe Benja Amarit extracts against human hepatocellular carcinoma and colon cancer cell by targeting apoptosis pathways

ETHNOPHARMACOLOGICAL RELEVANCE

A preparation of Benja Amarit (BJA) has been effectively used in folk medicine to treat diseases related to the liver and colon and forms of cancer for hundreds of years in Thailand. However, there has not been any research on BJA with regard to its anticancer activity against human hepatocellular carcinoma and colon cancer cells.

AIM OF THE STUDY

This study was to obtain the scientific supports for the traditional usage in anticancer potential of BJA extracts on hepatocellular carcinoma and colon cancer.

MATERIALS AND METHODS

The cytotoxic effects were determined using MTT assay. Apoptosis was quantitated by annexin V-FITC/PI staining. Caspases activities were measured by using specific substrates and colorimetric analysis. The protein expressions were determined by Western blot analysis. Reactive oxygen species (ROS) generation, mitochondrial transmembrane potential, and calcium ion levels were measured by specific fluorescence probes and flow cytometry. The chick embryo chorioallantoic membrane model has been used to study the in vivo anticancer activity. The phytochemical identification was performed by GC-MS and LC-MS.

RESULTS

Notably, 95% (BJA-95) and 50% (BJA-50) ethanolic extract of BJA inhibited hepatocellular carcinoma and colon cancer cell viability in a dose-dependent manner. While, the water extract of BJA (BJA-W) was not found to be toxic to both kinds of cancer cell lines. BJA extract induced both the extrinsic and intrinsic or mitochondria-mediated apoptosis pathways. Moreover, BJA-95 caused ROS generation and endoplasmic reticulum stress-mediated apoptosis. The extract exhibited the growth inhibitory effects on cancer cells in vivo. Phytochemical analysis revealed that the major active compounds were piperine, xanthotoxol and dihydrogambogic acid.

CONCLUSION

This study is the first to demonstrate anticancer efficiency of BJA extracts on human cancer cells. We consider BJA extract to be a potentially alternative cancer treatment and to be a promising candidate in the future development of antitumor agents.

Activity to Breast Cancer Cell Lines of Different Malignancy and Predicted Interaction with Protein Kinase C Isoforms of Royleanones

Plants have been used for centuries to treat several illnesses. The Plectranthus genus has a vast variety of species that has allowed the isolation of cytotoxic compounds with notable activities. The abietane diterpenes 6,7-dehydroroyleanone (DeRoy, 1), 7α-acetoxy-6β-hydroxyroyleanone (Roy, 2), and Parvifloron D (ParvD, 3) were obtained from Plectranthus spp. and showed promising biological activities, such as cytotoxicity. The inhibitory effects of the different natural abietanes (1-3) were compared in MFC7, SkBr3, and SUM159 cell lines, as well as SUM159 grown in cancer stem cell-inducing conditions. Based on the royleanones’ bioactivity, the derivatives RoyBz (4), RoyBzCl (5), RoyPr₂ (6), and DihydroxyRoy (7), previously obtained from 2, were selected for further studies. Protein kinases C (PKCs) are involved in several carcinogenic processes. Thus, PKCs are potential targets for cancer therapy. To date, the portfolio of available PKC modulators remains very limited due to the difficulty of designing isozyme-selective PKC modulators. As such, molecular docking was used to evaluate royleanones 1-6 as predicted isozyme-selective PKC binders. Subtle changes in the binding site of each PKC isoform change the predicted interaction profiles of the ligands. Subtle changes in royleanone substitution patterns, such as a double substitution only with non-substituted phenyls, or hydroxybenzoate at position four that flips the binding mode of ParvD (3), can increase the predicted interactions in certain PKC subtypes.

Lemongrass Extract Possesses Potent Anticancer Activity Against Human Colon Cancers, Inhibits Tumorigenesis, Enhances Efficacy of FOLFOX, and Reduces Its Adverse Effects

Current chemotherapeutics for metastatic colorectal cancers have limited success and are extremely toxic due to nonselective targeting. Some natural extracts have been traditionally taken and have shown anticancer activity. These extracts have multiple phytochemicals that can target different pathways selectively in cancer cells. We have shown previously that lemongrass (Cymbopogon citratus) extract is effective at inducing cell death in human lymphomas. However, the efficacy of lemongrass extract on human colorectal cancer has not been investigated. Furthermore, its interactions with current chemotherapies for colon cancer is unknown. In this article, we report the anticancer effects of ethanolic lemongrass extract in colorectal cancer models, and importantly, its interactions with FOLFOX and Taxol. Lemongrass extract induced apoptosis in colon cancer cells in a time and dose-dependent manner without harming healthy cells in vitro. Oral administration of lemongrass extract was well tolerated and effective at inhibiting colon cancer xenograft growth in mice. It enhanced the anticancer efficacy of FOLFOX and, interestingly, inhibited FOLFOX-related weight loss in animals given the combination treatment. Furthermore, feeding lemongrass extract to APC^min/+ transgenic mice led to the reduction of intestinal tumors, indicating its preventative potential. Therefore, this natural extract has potential to be developed as a supplemental treatment for colorectal cancer.

A Review of Cytotoxic Plants of the Indian Subcontinent and a Broad-Spectrum Analysis of Their Bioactive Compounds

Cancer or uncontrolled cell proliferation is a major health issue worldwide and is the second leading cause of deaths globally. The high mortality rate and toxicity associated with cancer chemotherapy or radiation therapy have encouraged the investigation of complementary and alternative treatment methods, such as plant-based drugs. Moreover, over 60% of the anti-cancer drugs are molecules derived from plants or their synthetic derivatives. Therefore, in the present review, an attempt has been made to summarize the cytotoxic plants available in the Indian subcontinent along with a description of their bio-active components. The review covers 99 plants of 57 families as well as over 110 isolated bioactive cytotoxic compounds, amongst which at least 20 are new compounds. Among the reported phytoconstituents, artemisinin, lupeol, curcumin, and quercetin are under clinical trials, while brazilin, catechin, ursolic acid, β-sitosterol, and myricetin are under pharmacokinetic development. However, for the remaining compounds, there is little or no information available. Therefore, further investigations are warranted on these subcontinent medicinal plants as an important source of novel cytotoxic agents.

Sturgeon (Acipenser)-Derived Chondroitin Sulfate Suppresses Human Colon Cancer HCT-116 Both In Vitro and In Vivo by Inhibiting Proliferation and Inducing Apoptosis

Chondroitin sulfate (CS), mainly present in the cartilage and bone of animals, is known as a potential food-derived bioactive that has several biological functions, such as anti-arthritic and anti-inflammatory activity. Sturgeon (Acipenser), an important fishery resource in China, contains an abundance of CS in their cartilage. In our previous study, we have extracted and purified CS from sturgeon cartilage. Herein, we further investigate the health benefits of sturgeon-derived chondroitin sulfate (SCS), especially for colorectal cancer treatment. The in vitro study indicated that SCS could inhibit the proliferation of the human colon cancer cell line HCT-116 in a dose-dependent manner, which was associated with cell cycle arrest. In addition, SCS also led to extensive cellular apoptosis in colon cancer cell HCT-116 cells. Meanwhile, an in vivo study showed that SCS treatment significantly inhibited the tumor development of xenograft HCT-116 in mice via proliferation suppression and apoptosis induction. Further, a mechanistic study demonstrated that the apoptosis induction was mainly due to the activation of the Bcl-2 family-associated mitochondrial pathway. Overall, our results provided a basis for SCS as a promising agent against colon cancer.

Synthesis, Biological Investigation and Docking Study of Novel Chromen Derivatives as Anti-Cancer Agents

BACKGROUND

According to the latest global cancer data, cancer burden rises to 18.1 million new cases and 9.6 million cancer deaths in 2018. Among that female breast cancer ranks as the fifth leading cause of death (627000 deaths, 6.6%). The main causative factor involved in breast cancer development and progression is the Estrogen Receptor (ER) which is the essential target for anti-cancer drug discovery. Since millennia ER-α has been considered as an oncology mark for the treatment of breast cancer.

METHODS

A series of novel 6-methyl-3-(3-oxo-1-phenyl-3-(4-(2-(piperidin-1-yl)ethoxy)phenyl)propyl)-2Hchromen- 2-one was designed, synthesized and screened for their anti-breast cancer activity against estrogen receptor-positive MCF-7, ZR-75-1 and negative MDA-MB-435 human breast cancer cell lines. Estrogen level of all the potent cytotoxic compounds were measured on day 30 of intoxication was compared with the control and N-methyl-N-nitrosourea (MNU) group. The docking study was performed to predict binding orientation towards the estrogen receptor-α.

RESULTS

Among the synthesized compounds C-3, C-5 and C-15 were showing potent cytotoxicity against estrogen receptor-positive MCF-7. The potent cytotoxic compounds C-3, C-5 and C-15 were further evaluated for in vivo anti-cancer activity by MNU induced mammary carcinoma in female sprague-dawley rats. The in vivo anticancer activity result shows that the compound C-5 has protuberant affinity towards estrogen receptor as standard TAM (Tamoxifen). The docking of the synthesized chromen derivatives showed interaction modes comparable to that of the co-crystallized ligands.

CONCLUSION

The designed class has very promising starting point for the development and further improvement in anti-breast cancer class of drugs.

Inhibitory Effects of Aucklandia lappa Decne. Extract on Inflammatory and Oxidative Responses in LPS-Treated Macrophages

Aucklandia lappa Decne., known as “Mok-hyang” in Korea, has been used for the alleviation of abdominal pain, vomiting, diarrhea, and stress gastric ulcers in traditional oriental medicine. We investigated the anti-inflammatory and antioxidative effects of the ethanol extract of Aucklandia lappa Decne. (ALDE) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. ALDE significantly inhibited the LPS-induced nitric oxide (NO) production and reduced inducible nitric oxide synthase (iNOS) expression in RAW 264.7 cells. The production of other proinflammatory mediators, including COX-2, interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α, was reduced by ALDE in LPS-stimulated RAW 264.7 cells. The mechanism underlying the anti-inflammatory effects of ALDE was elucidated to be the suppression of LPS-induced nuclear translocation of p65, followed by the degradation of IκB and the inhibition of the phosphorylation of mitogen-activated protein kinases (MAPK). In addition, ALDE showed enhanced radical scavenging activity. The antioxidant effect of ALDE was caused by the enhanced expression of heme oxygenase (HO-1) via stabilization of the expression of the nuclear transcription factor E2-related factor 2 (Nrf2) pathway. Collectively, these results indicated that ALDE not only exerts anti-inflammatory effects via the suppression of the NF-κB and MAPK pathways but also has an antioxidative effect through the activation of the Nrf2/HO-1 pathway.

Punicalagin promotes the apoptosis in human cervical cancer (ME-180) cells through mitochondrial pathway and by inhibiting the NF-kB signaling pathway

Increasing attention of plant derived therapeutic agents against cancer, investigating the anti-proliferative efficiency of plant derived chemicals have achieved increasing momentum for the design of anticancer drug. Punicalagin, dietary phytochemical altered the various cell signal transduction pathways associated with cell apoptosis and proliferation. This investigation was intended to examine the efficiency of punicalagin lying on cell viability so as to examine the molecular based punicalagin mechanism stimulated apoptosis via exploring the expression of Bcl-2 family proteins, and caspases also the cell cycle regulatory proteins p53 and NF-κB signaling in human cervical cancer cells. We also analyzed the morphological characteristic changes through mitochondrial membrane depolarization, reactive oxygen species (ROS) generation, TUNEL assay, AO/EtBr analysis in cervical cancer cells. Our findings demonstrated that punicalagin repressed the viability of cervical cancer cells in a dosereliant mode via stimulating mitochondrial mediated apoptosis. Moreover, our this study demonstrated that punicalagin blocked cervical cancer cell proliferation and stimulated cell apoptosis by suppressing NF-kappa B activity. Hence our study suggested that punicalagin exhibits opposing actions on NF-kappa B signaling networks to block cancer cell progression acts as a classical candidate for anticancer drug designing.

Activation of JNK and p38 in MCF-7 Cells and the In Vitro Anticancer Activity of Alnus hirsuta Extract

JNK and p38 are important mitogen-activated protein kinases (MAPKs) that respond to stress stimuli. The stress-activated MAPKs associated with apoptotic cell death play vital roles in mammalian cells. Alnus hirsuta, which contains abundant diarylheptanoids derivatives, is a valuable medicinal plant. The CHCl3 extract (AHC) containing platyphyllenone (1) and platyphyllone (3) as main compounds showed in vitro anticancer effects. We report the biological activities of A. hirsuta extract associated with the regulation of apoptosis and JNK and p38 in MCF-7 breast cancer cells. Levels of phospho-JNK and phospho-p38 by AHC treatment were evaluated by enzyme-linked immunosorbent assay (ELISA). ROS production, apoptotic effect, and DNA contents of the cells were measured by flow cytometry. The two diarylheptanoids 1 and 3 and the AHC extract exhibited cytotoxic effects on MCF-7 cells in MTT assay, with IC50 values of 18.1, 46.9, 260.0 μg/mL, respectively. AHC induced ROS generation and elevated the endogenous levels of phospho-JNK and phospho-p38. AHC resulted in apoptosis and cell cycle arrest. We suggest that the antitumor effect of A. hirsuta extract is achieved by apoptosis promotion and cell cycle arrest mediated by the activation of JNK and p38 signaling pathway via ROS generation.

Anticancer Potential of Raddeanin A, a Natural Triterpenoid Isolated from Anemone raddeana Regel

Natural compounds extracted from plants have gained immense importance in the fight against cancer cells due to their lesser toxicity and potential therapeutic effects. Raddeanin A (RA), an oleanane type triterpenoid is a major compound isolated from Anemone raddeana Regel. As an anticancer agent, RA induces apoptosis, cell cycle arrest, inhibits invasion, migration and angiogenesis in malignant cell lines as well as in preclinical models. In this systemic review, the pharmacological effects of RA and its underlying molecular mechanisms were carefully analyzed and potential molecular targets have been highlighted. The apoptotic potential of RA can be mediated through the modulation of Bcl-2, Bax, caspase-3, caspase-8, caspase-9, cytochrome c and poly-ADP ribose polymerase (PARP) cleavage. PI3K/Akt signaling pathway serves as the major molecular target affected by RA. Furthermore, RA can block cell proliferation through inhibition of canonical Wnt/β-catenin signaling pathway in colorectal cancer cells. RA can also alter the activation of NF-κB and STAT3 signaling pathways to suppress invasion and metastasis. RA has also exhibited promising anticancer potential against drug resistant cancer cells and can enhance the anticancer effects of several chemotherapeutic agents. Overall, RA may function as a promising compound in combating cancer, although further in-depth study is required under clinical settings to validate its efficacy in cancer patients.

Astaxanthin anticancer effects are mediated through multiple molecular mechanisms: A systematic review

During the latest decades, the interest on the effectiveness of natural compounds and their impact on human health constantly increased, especially on those demonstrating to be effective on cancer. Molecules coming from nature are currently used in chemotherapy like Taxol, Vincristine or Vinblastine, and several other natural substances have been showed to be active in reducing cancer cell progression and migration. Among them, astaxanthin, a xanthophyll red colored carotenoid, displayed different biological activities including, antinflammatory, antioxidant, proapoptotic, and anticancer effects. It can induce apoptosis through downregulation of antiapoptotic protein (Bcl-2, p-Bad, and survivin) expression and upregulation of proapoptotic ones (Bax/Bad and PARP). Thanks to these mechanisms, it can exert anticancer effects towards colorectal cancer, melanoma, or gastric carcinoma cell lines. Moreover, it possesses antiproliferative activity in many experimental models and enhances the effectiveness of conventional chemotherapic drugs on tumor cells underling its potential future use. This review provides an overview of the current knowledge on the anticancer potential of astaxanthin by modulating several molecular targets. While it has been clearly demonstrated its multitarget activity in the prevention and regression of malignant cells in in vitro or in preclinical investigations, further clinical studies are needed to assess its real potential as anticancer in humans.

Bitter apricot ethanolic extract induces apoptosis through increasing expression of Bax/Bcl-2 ratio and caspase-3 in PANC-1 pancreatic cancer cells

Pancreatic cancer is the fourth common cause of cancer death. Surgery and chemotherapy are the common treatment strategies for pancreatic cancer patients; however, the response rate is less than 20% at advanced stages. In recent years, growing interest has been dedicated to natural products. Bitter apricot seeds possess a number of pharmacological properties including antitumor activity and amygdalin from bitter apricot seeds can induce apoptosis. In this study, we investigated the cyto/genotoxic effects of bitter apricot ethanolic extract (BAEE) and amygdalin on human pancreatic cancer PANC-1 and normal epithelial 293/KDR cells. BAEE was assessed using high-performance liquid chromatography for the confirmation of the structure. The biological impacts of BAEE and amygdalin on PANC-1 and 293/KDR cells were evaluated by MTT assay, DAPI staining, AnnexinV/PI and Real-time qPCR analysis. BAEE and amygdalin inhibited cancer cell growth in a dose- and time-dependent manner. DAPI staining and flow cytometric analysis revealed fragmented nuclei and elevated numbers of early and late apoptotic cells, respectively. Also, increased Bax/Bcl-2 ratio and upregulation of caspase-3 further confirmed the occurrence of apoptosis in PANC-1 cells, but not in non-cancerous 293/KDR cells. These results indicate that BAEE could mediate apoptosis induction in cancer cells through a mitochondria dependent pathway. These findings suggest that BAEE functions as a potent pro-apoptotic factor for human pancreatic cancer cells without a significant effect on 293/KDR cells. Though, the potent anti-cancer components of BAEE should be further identified. Moreover, in vivo investigations are required to confirm bitter apricot ethanolic extract's clinical value as an anti-tumor drug.