Natural products as leads to anticancer drugs. Clin Transl Oncol. 2007;9:767-776. [PMID: 18158980 DOI: 10.1007/s12094-007-0138-9]

Andrographolide Suppresses MV4-11 Cell Proliferation through the Inhibition of FLT3 Signaling, Fatty Acid Synthesis and Cellular Iron Uptake

Background: Andrographolide (ADR), the main active component of Andrographis paniculata, displays anticancer activity in various cancer cell lines, among which leukemia cell lines exhibit the highest sensitivity to ADR. In particular, ADR was also reported to have reduced drug resistance in multidrug resistant cell lines. However, the mechanism of action (MOA) of ADR’s anticancer and anti-drug-resistance activities remain elusive. Methods: In this study, we used the MV4-11 cell line, a FLT3 positive acute myeloid leukemia (AML) cell line that displays multidrug resistance, as our experimental system. We first evaluated the effect of ADR on MV4-11 cell proliferation. Then, a quantitative proteomics approach was applied to identify differentially expressed proteins in ADR-treated MV4-11 cells. Finally, cellular processes and signal pathways affected by ADR in MV4-11 cell were predicted with proteomic analysis and validated with in vitro assays. Results: ADR inhibits MV4-11 cell proliferation in a dose- and time-dependent manner. With a proteomic approach, we discovered that ADR inhibited fatty acid synthesis, cellular iron uptake and FLT3 signaling pathway in MV4-11 cells. Conclusions: ADR inhibits MV4-11 cell proliferation through inhibition of fatty acid synthesis, iron uptake and protein synthesis. Furthermore, ADR reduces drug resistance by blocking FLT3 signaling.

Anti-cancer effects of Ajwa dates (Phoenix dactylifera L.) in diethylnitrosamine induced hepatocellular carcinoma in Wistar rats

BACKGROUND

Hepatocellular carcinoma (HCC) accounts for major cancer-related deaths despite current advanced therapies. Treatment and prognosis of HCC is better in patients with preserved liver function. Many natural products including ajwa dates (Phoenix dactylifera L.), are claimed to have hepatoprotective and HCC inhibitory effects, but most lack scientific validation. To prove our hypothesis, we attempted to evaluate the HCC inhibitory effects, and other beneficial properties of the aqueous extract of ajwa dates (ADE) in a rat model of diethylnitrosamine (DEN) induced liver cancer.

METHODS

Thirty-two male rats were divided into four groups of eight each as follows, Group A: untreated control; Group B: DEN control (180 mg/kg bw), Group C: DEN + ADE 0.5 g/kg bw; and Group D: DEN +1.0 g/kg bw. Rats from all groups were assessed for liver cancer progression or inhibition by evaluating histological, biochemical, antioxidant enzyme status, cytokines and gene expression profiles.

RESULTS

DEN treatment Groups (B, C, D) showed histological features of HCC and in rats treated with ADE (Groups C, D) partial to complete reversal of normal liver architecture was observed. Antioxidant enzymes such as superoxide dismutase (SOD), glutathione reductase (GR), glutatione peroxidase (GPx) and catalase (CAT) were increased, while the liver enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) levels and lipid peroxidation were significantly decreased in Group C and Group D compared to Group B. Pro-inflammatory cytokines such as interleukin (IL)-1α, IL-1β,, GM-CSF) were increased in the serum of rats in Group B while the anti-tumor cytokines (IL-2, IL-12) were increased in ADE treated Groups (C, D). In addition, Alpha-Feto Protein (AFP) and IL-6 gene expression levels were upregulated in Group B, while they were significantly downregulated in ADE treated Groups (C, D).

CONCLUSIONS

ADE helped in the reversal of DEN damaged liver towards normal. Restoration of anti-oxidant enzymes, liver enzymes, cytokines balance and gene expression to normal levels following ADE treatment indicates that ADE improves liver function and inhibits HCC. ADE can, therefore, be used together with conventional therapeutics for HCC.

Synthesis of Saccharumoside-B analogue with potential of antiproliferative and pro-apoptotic activities

A new series of phenolic glycoside esters, saccharumoside-B and its analogs (9b-9n, 10) have been synthesized by the Koenigs-Knorr reaction. Antiproliferative activities of the compounds (9b-9n, 10) were evaluated on various cancer cell lines including, MCF-7 breast, HL-60 leukemia, MIA PaCa-2 pancreatic, DU145 prostate, HeLa cervical and CaCo-2 colon, as well as normal human MCF10A mammary epithelial and human peripheral blood mononuclear cells (PBMC) by MTT assay. Compounds (9b-9n, 10) exhibited considerable antiproliferative effects against cancer cells with IC₅₀ range of 4.43 ± 0.35 to 49.63 ± 3.59 µM, but they are less cytotoxic on normal cells (IC₅₀ > 100 µM). Among all the compounds, 9f showed substantial antiproliferative activity against MCF-7 and HL-60 cells with IC₅₀ of 6.13 ± 0.64 and 4.43 ± 0.35, respectively. Further mechanistic studies of 9f were carried out on MCF-7 and HL-60 cell lines. 9f caused arrest of cell cycle of MCF-7 and HL-60 cells at G0/G1 phase. Apoptotic population elevation, mitochondrial membrane potential loss, increase of cytosolic cytochrome c and Bax levels, decrease of Bcl-2 levels and enhanced caspases-9 and -3 activities were observed in 9f-treated MCF-7 and HL-60 cells. These results demonstrate anticancer and apoptosis-inducing potentials of 9f in MCF-7 and HL-60 cells via intrinsic pathway.

Pien Tze Huang induces apoptosis and inhibits proliferation of 5-fluorouracil-resistant colorectal carcinoma cells via increasing miR-22 expression

The well-known traditional Chinese medicine formula Pien Tze Huang (PZH) has long been used to treat various malignancies, including colorectal cancer (CRC). It was recently reported that PZH possesses the ability to overcome multidrug resistance in CRC cells. In the present study, a 5-fluorouracil (5-FU) resistant human CRC cell line (HCT-8/5-FU) was used to further evaluate the effect of PZH on chemotherapy (chemo)-resistance and investigate the mechanisms through which this occurs. The results identified that PZH significantly reduced the viability and cell density of HCT-8/5-FU cells in a dose- and time-dependent manner (P<0.05). PZH inhibited cell survival, reduced the proportion of cells in S-phase, and suppressed the expression of pro-proliferative proteins cyclin D1 and cyclin-dependent kinase 4. In addition, PZH treatment induced nuclear condensation and fragmentation, activated caspase-9 and -3 and increased the pro-apoptotic Bcl-2-associated X protein/B-cell lymphoma 2 protein ratio. Furthermore, PZH treatment upregulated the expression of microRNA-22 (miR-22) and downregulated the expression of c-Myc (a target gene of miR-22). In conclusion, the findings from the present study suggest that PZH can overcome chemo-resistance in cancer cells, likely through increasing miR-22 expression, and by reversing the imbalance between levels of proliferation and apoptosis.

Bioassay-Guided Isolation and Evaluation of Antiproliferative Effects of (Z)-Ethylidene-4, 6-Dimethoxycoumaran-3-One from Pogostemon Quadrifolius (Benth.)

The aim of the study was to isolate and identify the major cytotoxic principle from plant leaves of Pogostemon quadrifolius (Benth.) and evaluate its antiproliferative potential against human cancer cells. Plant leaves were extracted sequentially with a soxhlet apparatus, using petroleum ether, chloroform and methanol solvents. Petroleum ether and chloroform extracts exhibited antiproliferative properties against Caco-2, HeLa, THP-1, MCF-7 and Jurkat E6-1cancer cell lines tested, but methanol extracts failed to exhibit such activity. The major antiproliferative principle from petroleum ether and chloroform extracts was isolated with the help of bioassay guided column chromatography. This cytotoxic compound was further analysed by UV, TLC, HPLC, LC-MS, GC-MS and NMR analyses and was identified to be novel: (Z)-ethylidene-4,6-dimethoxycoumaran-3-one (Compound 1). The half-maximal inhibitory concentrations for proliferation (IC₅₀) exhibited by compound 1 were 19.4, 23.1, 22.1, 35.9 and 8.32 µM against Caco-2, HeLa, THP-1, MCF-7 and Jurkat E6-1 cancer cell lines, respectively. Further experiments revealed that compound 1 triggered the apoptosis mode of cell death in cancer cell lines. Thus, the present study allowed isolation and identification of a novel cytotoxic natural compound, (Z)-ethylidene-4,6-dimethoxycoumaran-3-one, from plant leaves of P. quadrifolius (Benth.). Our pre-clinical study also indicated that compound 1 is particularly active in the acute T cell leukemia cell line (Jurkat E6-1) with potential for application as a chemotherapeutic agent in the future.

Dihydroartemisinin and gefitinib synergistically inhibit NSCLC cell growth and promote apoptosis via the Akt/mTOR/STAT3 pathway

Non‑small cell lung cancer (NSCLC) is among the leading causes of cancer‑associated mortality worldwide. In clinical practice, therapeutic strategies based on drug combinations are often used for the treatment of various types of cancer. The present study aimed to investigate the effects of the combination of dihydroartemisinin (DHA) and gefitinib on NSCLC. Cell Counting kit 8 assay was used to evaluate cell viability. Transwell assays were performed to investigate cellular migration and invasion, and cellular apoptosis was evaluated using the terminal deoxynucleotidyl transferase dUTP nick‑end labeling assay. Flow cytometry was used to investigate cell cycle distribution and the expression levels of target proteins were determined using western blot analysis. The results of the present study demonstrated that DHA (5, 10, 20, 50 and 100 µM) reduced cancer cell viability in a dose‑dependent manner in the NCI‑H1975 human NSCLC cell line and significantly enhanced gefitinib‑induced apoptosis. Furthermore, DHA and gefitinib co‑administration induced cell cycle arrest in G2/M phase, which was associated with a marked decline in the protein expression levels of G2/M regulatory proteins, including cyclin B1 and cyclin‑dependent kinase 1. The addition of DHA appeared to potentiate the inhibitory actions of gefitinib on the migratory and invasive capabilities of NCI‑H1975 cells. DHA and gefitinib co‑administration also downregulated the expression levels of phosphorylated (p)‑Akt, p‑mechanistic target of rapamycin, p‑signal transducer and activator of transcription 3 and B‑cell lymphoma 2 (Bcl‑2), and upregulated the expression of Bcl‑2‑associated X protein. In conclusion, the present results suggested that the combination of DHA and gefitinib may have potential as a novel and more effective therapeutic strategy for the treatment of patients with NSCLC.

Antiproliferative activity of Haematoxylum brasiletto H. Karst

BACKGROUND

Haematoxylum brasiletto is a tree that grows in Central America, commonly known as "Palo de Brasil," which is used in the traditional medicine for the treatment of cancer and gastric ulcers.

OBJECTIVE

The aim of this study was to isolate the compounds responsible for antiproliferative activity of H. brasiletto.

MATERIALS AND METHODS

A bioassay-guided fractionation of ethanol extract of H. brasiletto was performed using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide cell proliferation assay to measure the antiproliferative activity on six human cancer cell lines (A549, LS180, HeLa, SiHa, MDA-MB-231, and NCI-H1299) and one human noncancer cell line (ARPE-19). The ethanol extract was partitioned with hexane, dichloromethane, and ethyl acetate. The active dichloromethane fraction was fractioned by silica-column chromatography, and active subfractions were separated using preparative-thin layer chromatography. The chemical structure of an isolated compound was elucidated with different chemical and spectroscopic methods.

RESULTS

The flavonoid brazilin (1) was isolated from the heartwood of H. brasiletto. The measurement of antiproliferative activity showed that brazilin can inhibit the growth of SiHa, MDA-MB-231, A549, and NCI-H1299 cell lines by 50% at doses of 44.3, 48.7, 45.4, and 48.7 μM, respectively. Furthermore, the flavonoid showed a high antiproliferative activity on LS 180 and HeLa with IC50 values of 62.2 and 71.9 μM, respectively. Brazilin also exhibited a high antiproliferative activity on the human noncancer cell line ARPE-19 with an IC50 value of 37.9 μM.

CONCLUSIONS

Brazilin: (6aS, 11bR)-7,11b-Dihidro-6H-indeno[2,1-c] cromeno-3,6a, 9,10-tetrol was isolated; this compound demonstrated antiproliferative activity against several human cancer cell lines. This work demonstrated that brazilin, a flavonoid isolated and characterized of H. brasiletto, has antiproliferative activity against cancer cell lines.

SUMMARY

The flavonoid brazilin was isolated from the heartwood of H. brasilettoBrazilin is able to inhibit the growth of SiHa, MDA-MB-231, A549 and NCI- H1299 cancerous cell linesBrazilin exhibited a moderate antiproliferative activity on the human non-cancer cell line ARPE-19Brazilin demonstrated to have antiproliferative activity against human cancer cell lines and could be a potential source of anticancer agents. Abbreviations used: MTT: [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium]; FBS: Fetal bovine serum; TLC: Thin layer chromatography.

Cucurbitacin B inhibits cell proliferation and induces apoptosis in human osteosarcoma cells via modulation of the JAK2/STAT3 and MAPK pathways

Osteosarcoma (OS) is the most commonly diagnosed tumor of the bones in children and young adults. Even with conventional therapies the 5-year survival rate is ~65% in patients with OS. Considering the side effects and aggressiveness of malignant bone tumors, research is focussing on multi-targeted strategies in treatment. Cucurbitacin B, a triterpenoid compound has been demonstrated to induce apoptosis in various cancer cell types. The Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signalling cascades and mitogen activated protein kinases (MAPK) signalling cascades are critical regulators of tumorigenesis. The present study assessed the influence of cucurbitacin B on the viability and expression of MAPKs and proteins of the JAK2/STAT3 cascades in human OS cells (U-2 OS). Cucurbitacin B (20-100 µM) significantly reduced cell viability (P<0.05) and induced apoptosis, as assessed by MTT and Annexin V/propidium iodide staining, along with inhibiting cell migration. Gelatin zymography revealed supressed activities of matrix metalloproteinase (MMP-)2 and 9. Furthermore, cucurbitacin B effectively upregulated the apoptotic pathway and caused the effective inhibition of MAPK signalling and JAK2/STAT3 cascades. Multifold suppression of vascular endothelial growth factor by cucurbitacin B was also observed, indicating inhibition of angiogenesis. Thus, by downregulating major pathways-MAPK and JAK2/STAT3 and MMPs, cucurbitacin B has potent anti-proliferative and anti-metastatic effects that require further investigation with regards to cancer treatment.

Induction of intrinsic apoptosis in leukaemia stem cells and in vivo zebrafish model by betulonic acid isolated from Walsura pinnata Hassk (Meliaceae)

BACKGROUND

Leukaemia stem cells (LSC) have been associated with disease relapse and chemotherapy resistance. Betulonic acid (BA), a pentacyclic lupane-type triterpenoid, was reported to exhibit cytotoxicity toward various cancer cells and to be capable of inducing intrinsic apoptosis in solid tumours. However, the in vitro and in vivo apoptotic effects of BA against LSC remain unknown.

HYPOTHESIS/PURPOSE

We aimed to determine whether BA isolated from bark of Walsura pinnata Hassk (Meliaceae) has pro-apoptotic effects on LSC in in vitro and in vivo models.

STUDY DESIGN/METHODS

The population of high purity LSC was isolated from the Kasumi-1 cell line using magnetic sorting and characterised by flow cytometry. Cell viability was assessed using the MTS assay to examine dose- and time-dependent effects. The colony formation assay was performed in MethoCult® H4435 enriched media. Apoptosis was analysed using Annexin-V and propidium iodide staining, mitochondrial transmembrane potential was studied using JC-1 staining, and expression of apoptosis related genes (BAX, Bcl-2 and survivin) was evaluated by real time-polymerase chain reaction (RT-PCR). Caspase 3/7 and 9 activities were monitored through Promega Caspase-Glo® over a period of 24h. The in vivo antileukaemia activity was evaluated using LSC xenotransplanted zebrafish, observed for DNA fragmentation from apoptosis by TUNEL assay.

RESULTS

BA maintained its potency against the LSC population in comparison to parental Kasumi-1 cells (fold differences ≤ 1.94) over various treatment time points and significantly inhibited the formation of colonies by LSC. Apoptosis was triggered by BA through the upregulation of BAX and suppression of Bcl-2 and survivin genes with the loss of mitochondrial transmembrane potential, leading to the activation of caspase 9 followed by downstream caspase 3/7. BA was able to suppressed leukaemia formation and induced apoptosis in LSC xenotransplanted zebrafish.

CONCLUSIONS

The results demonstrate that BA inhibited the proliferative and colonogenic properties of LSC. BA induced apoptosis in LSC through the mitochondria pathway and was effective in the in vivo zebrafish model. Therefore, BA could be a lead compound for further development into a chemotherapy agent against LSC.

Synthesis and biological evaluation of novel 3-O-tethered triazoles of diosgenin as potent antiproliferative agents

Diosgenin, a promising anticancer steroidal sapogenin, was isolated from Dioscorea deltoidea. Keeping its stereochemistry rich architecture intact, a scheme for the synthesis of novel diosgenin analogues was designed using Cu (I)-catalysed alkyne-azide cycloaddition in order to study their structure-activity relationship. Both diosgenin and its analogues exhibited interesting anti-proliferative effect against four human cancer cell lines viz. HBL-100 (breast), A549 (lung), HT-29 (colon) and HCT-116 (colon) using [3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazoliumbromide] (MTT) assay. Among the synthesized analogues, Dgn-1 bearing a simple phenyl R moiety attached via triazole to the parent molecule was identified as the most potent analogue against A549 cancer cell line having IC₅₀ of 5.54μM, better than the positive control (BEZ-235). Dgn-2 and Dgn-5 bearing o-nitrophenyl and o-cyanophenyl R moieties respectively, displayed impressive anti-proliferative activity against all the tested human cancer cell lines with IC₅₀ values ranging from 5.77 to 9.44μM. The structure-activity relationship (SAR) revealed that the analogues with simple phenyl R moiety or electron withdrawing ortho substituted R moieties seem to have beneficial impact on the anti-proliferative activity.

Cancer Cell Specific Delivery of Photosystem I Through Integrin Targeted Liposome Shows Significant Anticancer Activity

Many anticancer drugs are developed for the treatment of cancer from natural sources. Photosystem I (PSI), a protein complex present in the chloroplast, is involved in photosynthesis and generates reactive oxygen species (ROS) in plant. Here, we used the ROS generation property of PSI for cancer therapy. We show that PSI can enter into different kinds of cancer cell like human lung carcinoma (A549) and mouse melanoma (B16F10) cell lines and generate ROS inside the cells. It inhibits the proliferation of cancer cell and causes apoptotic death of cancer cells. We also show that PSI induces apoptosis through mitochondria-dependent internal pathway, induces caspase3, causes DNA fragmentation, and arrests cell cycle at SubG0 phase. We also prepared, using C₁₆-LDV lipopeptide [C16 long chain attached on the N-terminal of the tripeptide containing amino acids leucine (L), aspartic acid (D), and valine (V) abbreviated as NH₂-LDV-COOH], α₄β₁ integrin targeted liposomal formulation of PSI, which specifically kills the cancer cell without affecting normal cells, and it is found to be more potent compared to clinically used drug doxorubicin. Finally, we found that LDV liposomal formulation of PSI inhibits the growth of tumor in C57BL/6J mice model.

Apoptotic induction and inhibition of NF-κB signaling pathway in human prostatic cancer PC3 cells by natural compound 2,2'-oxybis (4-allyl-1-methoxybenzene), biseugenol B, from Litsea costalis: an in vitro study

Litsea is considered as an evergreen genus distributed in tropical and subtropical Asia; this genus belongs to the large family of Lauraceae. In this study, the cell-death metabolism of biseugenol B was investigated. Nuclear condensation, cell permeability, mitochondrial membrane potential (MMP) and release of cytochrome c have been detected in human prostate cancer cell line (PC3) treated with biseugenol B by high content screening (HCS). Fluorescent analysis was conducted to examine the reactive oxygen species formation. To determine the mechanism of cell death, the levels of Bcl-cell lymphoma (Bcl)-2 proteins, Bcl-2-associated X (Bax) protein and anti-apoptosis heat-shock protein 70 were tested by applying reverse transcription polymerase chain reaction and Western blot. Bioluminescent assays were also performed to assess the level of caspases such as 3/7, 8 and 9 during treatment. Furthermore, the involvement of nuclear factor kappa-B (NF-κB) was examined by Western blot and HCS. Biseugenol B showed significant cytotoxicity toward PC3 with no toxicity toward normal prostate cells (RWPE-1), which indicates that biseugenol B has qualities that induce apoptosis in tumor cells. The treatment of PC3 cells with biseugenol B provoked apoptosis with cell-death-transducing signals. Downregulation of Bcl-2 and upregulation of Bax regulated the MMP, which in turn caused the release of cytochrome c from mitochondria into cytosol. The release of cytochrome c activated caspase-9, which consequently activated caspase-3/7 with the cleaved poly(ADP-ribose) polymerase protein, thereby resulting in apoptosis alteration. Involvement of an extrinsic apoptosis pathway was exhibited by the increase in caspase-8, while the increase in caspase-3/7 and caspase-9 demonstrated involvement of an intrinsic apoptosis pathway. Meanwhile, no significant increase was observed in caspases 3/7, 8 or 9 in normal prostate cells (RWPE-1) after treatment with biseugenol B. Prevention of NF-κB translocation from the cytosol to the nucleus occurred in PC3 after treatment with biseugenol B. The results of our study reveal that biseugenol B triggers the apoptosis of PC3 cells via intrinsic and extrinsic apoptosis pathways and inhibition of NF-κB signaling pathway. Our findings suggest that biseugenol B is a potentially useful agent for prostate cancer treatment.

Novel anti-tubulin agents from plant and marine origins: insight from a molecular modeling and dynamics study

The screening of a variety of botanical species and marine organisms provided satisfactory novel tubulin binding agents (TBAs).

Rational design of food-grade polyelectrolyte complex coacervate for encapsulation and enhanced oral delivery of oenothein B

Controlled release of OeB through GI tract using CPP–CS nanoparticles cross-linked with genipin was achievable.

Anticancer activity of Nelumbo nucifera stamen extract in human colon cancer HCT-116 cells in vitro

The aim of the present study was to investigate the anticancer activities of Nelumbo nucifera (Ba lotus) stamen ethanol crude extract (BLSEE) in human colon carcinoma HCT-116 cells. MTT assay, flow cytometry analysis and reverse transcription-polymerase chain reaction assay were employed to investigate the anticancer mechanisms of BLSEE (100, 200 and 400 µg/ml) in HCT-116 cells. BLSEE reduced HCT-116 cell proliferation in a dose-dependent manner. BLSEE treatment also significantly increased the sub-G1 population in HCT-116 cells (P=0.0020 at 400 µg/ml), as shown by flow cytometry assay. Following treatment with BLSEE, the mRNA levels of the apoptosis-associated factors Fas, Fas ligand, tumor necrosis factor-related apoptosis-inducing ligand, death receptor 4 (DR4), death receptor 5 (DR5), caspases 3, 8 and 9, and B-cell lymphoma-2 (Bcl-2) associated X protein were increased, and the expression of anti-apoptotic Bcl-2 and Bcl-extra large was decreased in HCT-116 cells. The mRNA levels of matrix metalloproteinase (MMP)-2, MMP-9, TIMP metallopeptidase inhibitor 1 and TIMP metallopeptidase inhibitor 2 were also regulated by BLSEE treatment. In addition, BLSEE was able to modulate the expression of inflammation-associated nuclear factor-κB, inhibitory κBα, inducible nitric oxide synthase and cyclooxygenase 2 in HCT-116 cells. The present study clearly indicated the cytotoxicity of BLSEE in HCT-116 cells through induced cellular apoptosis. These results also suggested the BLSEE may be a powerful agent against colon cancer cells.

Anticancer and anti-inflammatory activities of girinimbine isolated from Murraya koenigii

Therapy that directly targets apoptosis and/or inflammation could be highly effective for the treatment of cancer. Murraya koenigii is an edible herb that has been traditionally used for cancer treatment as well as inflammation. Here, we describe that girinimbine, a carbazole alkaloid isolated from M. koenigii, induced apoptosis and inhibited inflammation in vitro as well as in vivo. Induction of apoptosis in human colon cancer cells (HT-29) by girinimbine revealed decreased cell viability in HT-29, whereas there was no cytotoxic effect on normal colon cells. Changes in mitochondrial membrane potential, nuclear condensation, cell permeability, and cytochrome c translocation in girinimbine-treated HT-29 cells demonstrated involvement of mitochondria in apoptosis. Early-phase apoptosis was shown in both acridine orange/propidium iodide and annexin V results. Girinimbine treatment also resulted in an induction of G0/G1 phase arrest which was further corroborated with the upregulation of two cyclin-dependent kinase proteins, p21 and p27. Girinimbine treatment activated apoptosis through the intrinsic pathway by activation of caspases 3 and 9 as well as cleaved caspases 3 and 9 which ended by triggering the execution pathway. Moreover, apoptosis was confirmed by downregulation of Bcl-2 and upregulation of Bax in girinimbine-treated cells. In addition, the key tumor suppressor protein, p53, was seen to be considerably upregulated upon girinimbine treatment. Induction of apoptosis by girinimbine was also evidenced in vivo in zebrafish embryos, with results demonstrating significant distribution of apoptotic cells in embryos after a 24-hour treatment period. Meanwhile, anti-inflammatory action was evidenced by the significant dose-dependent girinimbine inhibition of nitric oxide production in lipopolysaccharide/interferon-gamma-induced cells along with significant inhibition of nuclear factor-kappa B translocation from the cytoplasm to nucleus in stimulated RAW 264.7 cells. Girinimbine was also shown to have considerable antioxidant activity whereby 20 μg/mL of girinimbine was equivalent to 82.17±1.88 μM of Trolox. In mice with carrageenan-induced peritonitis, oral pretreatment with girinimbine helped limit total leukocyte migration (mainly of neutrophils), and reduced pro-inflammatory cytokine levels (interleukin-1beta and tumor necrosis factor-alpha) in the peritoneal fluid. These findings strongly suggest that girinimbine could act as a chemopreventive and/or chemotherapeutic agent by inducing apoptosis while suppressing inflammation. There is a potential for girinimbine to be further investigated for its applicability in treating early stages of cancer.

Xanthium strumarium extract inhibits mammalian cell proliferation through mitotic spindle disruption mediated by xanthatin

ETHNOPHARMACOLOGICAL RELEVANCE

Xanthium strumarium L. is a member of the Asteraceae family popularly used with multiple therapeutic purposes. Whole extracts of this plant have shown anti-mitotic activity in vitro suggesting that some components could induce mitotic arrest in proliferating cells.

AIM OF THE SUDY

Aim of the present work was to characterize the anti-mitotic properties of the X. strumarium whole extract and to isolate and purify active molecule(s).

MATERIALS AND METHODS

The capacity of the whole extract to inhibit mitotic progression in mammalian cultured cells was investigated to identify its anti-mitotic activity. Isolation of active component(s) was performed using a bioassay-guided multistep separation procedure in which whole extract was submitted to a progressive process of fractionation and fractions were challenged for their anti-mitotic activity.

RESULTS

Our results show for the first time that X. strumarium whole extract inhibits assembly of the mitotic spindle and spindle-pole separation, thereby heavily affecting mitosis, impairing the metaphase to anaphase transition and inducing apoptosis. The purification procedure led to a fraction with an anti-mitotic activity comparable to that of the whole extract. Chemical analysis of this fraction showed that its major component was xanthatin.

CONCLUSIONS

The present work shows a new activity of X. strumarium extract, i.e. the alteration of the mitotic apparatus in cultured cells that may be responsible for the anti-proliferative activity of the extract. Anti-mitotic activity is shown to be mainly exerted by xanthatin.

Chemical Composition, Cytotoxic, Apoptotic and Antioxidant Activities of Main Commercial Essential Oils in Palestine: A Comparative Study

Background: Essential oils (EOs) are complex mixtures of several components gifted with a wide array of biological activities. The present research was designed to evaluate whether commercial essential oils could be effective by examining their in vitro antioxidant, cytotoxic, and apoptotic properties of nine commercially available EOs in Palestine, namely, African rue, basil, chamomile, fennel, fenugreek, ginger, spearmint, sage, and thyme, and to assure their effective use. Methods: The cytotoxic activity was determined using HT29-19(A) non-muco secreting and HT29-muco secreting (MS) cell lines. MTT, and trypan blue tests, and DPPH radical scavenging have also been assayed on the studied EOs. Results: In this work chamomile oil showed the lowest IC₅₀ at the content of 60 µL/mL, while all other EOs reached such a decrease when 70–80 µL/mL was used on HT-29 (MS) cell lines. In HT-29 19(A) cells, 50% of viability was obtained when 80 µL/mL of ginger and African rue was used, while all other EOs needed more than 80 µL/mL to reach such a decline in viability. Otherwise, an MTT assay on HT-29 (MS) displayed ginger EO with the lowest IC₅₀, followed by African rue and sage, with 40, 48 and 53 µL/mL, respectively. Otherwise, for the rest of the EOs, the IC₅₀ was obtained by assaying around 80 µL/mL. Ginger showed the lowest IC₅₀ with 60 µL/mL and thyme was the highest with 77 µL/mL when HT-29 19(A) cells were used. Conclusion: The most active EOs were found to be ginger, chamomile oil, and African rue. In general, the results demonstrate that most commercial EOs tested in this work possess low, or no biological activities; this may be due to processing, storage conditions, and handling or other reasons, which may cause losses in the biological and pharmacological properties that endemically exist in the Eos; hence, more investigation is still required on commercial EOs before they are recommended to the public.

Drug discovery using clinical outcome-based Connectivity Mapping: application to ovarian cancer

Background

Epithelial ovarian cancer (EOC) is the fifth leading cause of cancer death among women in the United States (5 % of cancer deaths). The standard treatment for patients with advanced EOC is initial debulking surgery followed by carboplatin-paclitaxel combination chemotherapy. Unfortunately, with chemotherapy most patients relapse and die resulting in a five-year overall survival around 45 %. Thus, finding novel therapeutics for treating EOC is essential. Connectivity Mapping (CMAP) has been used widely in cancer drug discovery and generally has relied on cancer cell line gene expression and drug phenotype data. Therefore, we took a CMAP approach based on tumor information and clinical endpoints from high grade serous EOC patients.

Methods

We determined tumor gene expression signatures (e.g., sets of genes) associated with time to recurrence (with and without adjustment for additional clinical covariates) among patients within TCGA (n = 407) and, separately, from the Mayo Clinic (n = 326). Each gene signature was inputted into CMAP software (Broad Institute) to determine a set of drugs for which our signature “matches” the “reference” signature, and drugs that overlapped between the CMAP analyses and the two studies were carried forward for validation studies involving drug screens on a set of 10 EOC cell lines.

Results

Of the 11 drugs carried forward, five (mitoxantrone, podophyllotoxin, wortmannin, doxorubicin, and 17-AAG) were known a priori to be cytotoxics and were indeed shown to effect EOC cell viability.

Conclusions

Future research is needed to investigate the use of these CMAP and similar analyses for determining combination therapies that might work synergistically to kill cancer cells and to apply this in silico bioinformatics approach using clinical outcomes to other cancer drug screening studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-3149-5) contains supplementary material, which is available to authorized users.

Cell cycle arrest and mechanism of apoptosis induction in H400 oral cancer cells in response to Damnacanthal and Nordamnacanthal isolated from Morinda citrifolia

Oral cancer is the eleventh most prevalent cancer worldwide. The most prevalent oral cancer is oral squamous cell carcinoma (OSCC). Damnacanthal (DAM) and nordamnacanthal (NDAM), the anthraquinone compounds, are isolated from the root of Morinda citrifolia L. (Noni), which has been used for the treatment of several chronic diseases including cancer. The objectives of this study were to evaluate the cytotoxicity, cell death mode, cell cycle, and the molecular mechanism of apoptosis induced by DAM and NDAM on OSCC. The cytotoxic effects of these compounds against OSCC cell lines were determined by MTT assay. The cell death mode was analysed by DNA laddering and FITC-annexin V/PI flow cytometric assays. In addition, the mechanism of apoptosis induced by DAM and NDAM was detected using mitochondrial membrane potential, Cytochrome c, and caspases assays. Finally, the effect of DAM and NDAM on cell cycle phase distribution of OSCC cells was detected by flow cytometry. In the present study, DAM and NDAM showed cytotoxicity towards OSCC cell lines and the maximum growth inhibition for both compounds was observed in H400 cells with IC50 value of 1.9 and 6.8 μg/ml, respectively, after 72 h treatment. The results also demonstrated the inhibition of H400 OSCC cells proliferation, internucleosomal cleavage of DNA, activation of intrinsic apoptosis pathway, and cell cycle arrest caused by DAM and NDAM. Therefore, these findings suggest that DAM and NDAM can be potentially used as antitumor agents for oral cancer therapy.

Recent Advances in the Development of Antineoplastic Agents Derived from Natural Products

Through years of evolutionary selection pressures, organisms have developed potent toxins that coincidentally have marked antineoplastic activity. These natural products have been vital for the development of multiagent treatment regimens currently employed in cancer chemotherapy, and are used in the treatment of a variety of malignancies. Therefore, this review catalogs recent advances in natural product-based drug discovery via the examination of mechanisms of action and available clinical data to highlight the utility of these novel compounds in the burgeoning age of precision medicine. The review also highlights the recent development of antibody-drug conjugates and other immunotoxins, which are capable of delivering highly cytotoxic agents previously deemed too toxic to elicit therapeutic benefit preferentially to neoplastic cells. Finally, the review examines natural products not currently used in the clinic that have novel mechanisms of action, and may serve to supplement current chemotherapeutic protocols.

Paris saponin VII suppresses osteosarcoma cell migration and invasion by inhibiting MMP‑2/9 production via the p38 MAPK signaling pathway

Metastasis is the primary cause of mortality in osteosarcoma. Targeting metastasis is a major strategy in osteosarcoma treatment. As a traditional Chinese medicine, Trillium tschonoskii Maxim has been widely used in the therapy of various diseases, including cancer. However, currently there is no evidence regarding the anti‑metastasic effect of Paris saponin VII (PS VII), which is extracted from Trillium tschonoskii Maxim, on osteosarcoma cells and its underling mechanisms. The present study aimed to examine the effect of PS VII on the migration and invasion of osteosarcoma cells. Viability and proliferation of osteosarcoma cells were examined by MTT assay. Migration and invasion of osteosarcoma cells was then detected using scratch wound healing assays and Transwell assays, respectively. Additionally, the expression of matrix metalloproteinase (MMP)‑2 and ‑9 was determined at the mRNA and protein level following treatment with PS VII. Mitogen‑activated protein kinase (MAPK) expression was also detected by western blot analysis. Finally, an inhibitor of p38 MAPK was used to verify the effect of PS VII on the expression of MMP‑2 and ‑9, as well as the migration and invasion osteosarcoma cells. This demonstrated that the proliferation, migration and invasion of the osteosarcoma cells were suppressed following treatment with PS VII. PS VII downregulated the expression of MMP‑2 and ‑9 in a dose‑ and time‑dependent manner. PS VII also exerted its ability to downregulate the phosphorylation of p38 MAPKs. Furthermore, by using a p38 inhibitor, SB203580, the role of PS VII in MMP‑2 and ‑9 expression and osteosarcoma cell invasion was revealed. Taken together, these results demonstrated that PS VII suppresses the migration and invasion of osteosarcoma cells via the p38 MAPK signaling pathway.

NKCT1 (purified Naja kaouthia protein toxin) conjugated gold nanoparticles induced Akt/mTOR inactivation mediated autophagic and caspase 3 activated apoptotic cell death in leukemic cell

BACKGROUND

Gold nanoparticle (GNP) and snake venom protein toxin NKCT1 was conjugated as stated earlier (Bhowmik et al., 2013). The aim of this study was to explore the caspase dependent apoptotic pathway and autophagy inducing ability of gold nanoparticles tagged snake venom protein toxin NKCT1 (GNP-NKCT1) in human leukemic U937 and K562 cell line.

METHODS

GNP-NKCT1 induced apoptosis in U937 and K562 cell line were assessed through mitochondrial membrane potential assay, ROS generation assay, caspase 3 pathways and western blotting. GNP-NKCT1 induced autophagic pathway was detected through Akt, mTOR and PI3K expression by western blotting. Autophagic cell death also checked after addition of caspase 3 inhibitor and which also reconfirmed by western blotting of autophagic marker protein, lysosomal staining.

RESULTS

Loss of mitochondrial membrane potential was occurred in both the leukemic cell line after induction by GNP-NKCT1 and treatment of which also exhibited high ROS generation. Caspase 3 expression of cell was also increased. With caspase 3 inhibitor, GNP-NKCT1 downregulated PI3K/Akt and mTOR expression and thus undergoing autophagic cell death. Lysosomal staining confirmed lysosomal enzyme involvement in the autophagic response. Up regulation of Atg 3, Atg12, Beclin 1, LC3-II protein and BIF-1 and down regulation of Atg4B were also showed by blotting.

CONCLUSION

The results demonstrated that conjugation of Gold nanoparticles with NKCT1 could induce an alternate cell death pathway other than apoptosis in the form of autophagy in leukemic cell.

GENERAL SIGNIFICANCE

This study might provide the understanding area of chemotherapeutic drug development from natural resources like snake venoms.

Phytoconstituents as apoptosis inducing agents: strategy to combat cancer

Advancement in the field of cancer molecular biology has aided researchers to develop various new chemopreventive agents which can target cancer cells exclusively. Cancer chemopreventive agents have proficiency to inhibit, reverse and delay process of carcinogenesis during its early and later course. Chemopreventive agents can act as antioxidative, antimutagenic/antigenotoxic, anti-inflammatory agents or via aiming various molecular targets in a cell to induce cell death. Apoptosis is a kind of cell death which shows various cellular morphological alterations such as cell shrinkage, blebbing of membrane, chromatin condensation, DNA fragmentation, formation of apoptotic bodies etc. Nowadays, apoptosis is being one of the new approaches for the identification and development of novel anticancer therapies. For centuries, plants are known to play part in daily routine from providing food to management of human health. In the last two decades, diverse phytochemicals and various botanical formulations have been characterized as agents that possess potential to execute cancer cells via inducing apoptosis. Data obtained from the research carried out globally pointed out that natural products are the potential candidates which have capability to combat cancer. In the present review, we surveyed literature on natural products which throws light on the mechanism through which these phytochemicals induce apoptosis in cancer cells.

Pharmacophore modeling and in silico toxicity assessment of potential anticancer agents from African medicinal plants

Molecular modeling has been employed in the search for lead compounds of chemotherapy to fight cancer. In this study, pharmacophore models have been generated and validated for use in virtual screening protocols for eight known anticancer drug targets, including tyrosine kinase, protein kinase B β, cyclin-dependent kinase, protein farnesyltransferase, human protein kinase, glycogen synthase kinase, and indoleamine 2,3-dioxygenase 1. Pharmacophore models were validated through receiver operating characteristic and Güner–Henry scoring methods, indicating that several of the models generated could be useful for the identification of potential anticancer agents from natural product databases. The validated pharmacophore models were used as three-dimensional search queries for virtual screening of the newly developed AfroCancer database (~400 compounds from African medicinal plants), along with the Naturally Occurring Plant-based Anticancer Compound-Activity-Target dataset (comprising ~1,500 published naturally occurring plant-based compounds from around the world). Additionally, an in silico assessment of toxicity of the two datasets was carried out by the use of 88 toxicity end points predicted by the Lhasa’s expert knowledge-based system (Derek), showing that only an insignificant proportion of the promising anticancer agents would be likely showing high toxicity profiles. A diversity study of the two datasets, carried out using the analysis of principal components from the most important physicochemical properties often used to access drug-likeness of compound datasets, showed that the two datasets do not occupy the same chemical space.

Cancer Phytotherapy: Recent Views on the Role of Antioxidant and Angiogenesis Activities

Nowadays, increases in resistance of tumors to the current therapeutic agents have become a problematic issue. Therefore, efforts to discover new anticancer compounds with high sensitivity of cancer cells are extending. Animal and laboratory researches have shown that exogenous antioxidants are able to help prevent the free radical damage associated with the development of cancer. However, researches in human beings have not demonstrated convincingly that taking antioxidants can reduce the risk of developing cancer. Angiogenesis is also a natural condition that controls the formation of new blood vessels from the available vessels. Today, it is believed that most of the cancers have angiogenesis potential and their growth, metastasis, and invasion depend on angiogenesis. Several compounds with plant origin and with anti-angiogenic properties have been identified. The aim of this study is to review recently published articles about anticancer drugs obtained from plants with antioxidant and anti-angiogenesis properties.

Ovatodiolide of Anisomeles indica Exerts the Anticancer Potential on Pancreatic Cancer Cell Lines through STAT3 and NF-κB Regulation

Pancreatic cancer is the eighth leading cause of cancer death worldwide. Patients with pancreatic cancer are normally diagnosed at an advanced stage and present poor survival rate. Ovatodiolide (OV), a bioactive macrocyclic diterpenoid isolated from Anisomeles indica, showed cytotoxicity effects in pancreatic cancer cells by inhibiting cell proliferation and inducing apoptosis. Moreover, not only were cell adhesion and invasion markedly suppressed in a dose-dependent manner, but the mRNA expression of matrix metalloproteinase-9 (MMP-9) and focal adhesion kinase (FAK) was also significantly decreased. Western blot analysis indicated that OV potently suppressed the phosphorylation of STAT-3 and its upstream kinase including ERK1/2, P38, and AKT Ser473. Meanwhile, OV inactivated the nuclear factor kappa B (NF-κB) by inhibiting IκB kinase (IKK α/β) activation and the subsequent suppression of inhibitor of kappa B (IκB) phosphorylation. These results demonstrated that OV could potentially inhibit Mia-PaCa2 cancer cells proliferation and induce apoptosis through modulation of NF-κB and STAT3 pathway. Moreover, OV suppressed cell invasiveness and interfered with cell-matrix adhesion in Mia-PaCa2 cancer cells by reducing MMP-9 and FAK transcription through suppressing NF-κB and STAT3 pathway. Taken together, our findings reveal a new therapeutic and antimetastatic potential of ovatodiolide for pancreatic cancer remedy.

Oleanolic acid inhibits colorectal cancer angiogenesis in vivo and in vitro via suppression of STAT3 and Hedgehog pathways

Angiogenesis is an essential process of cancer progression and is regulated by multiple intracellular signaling pathways, including signal transducer and activator of transcription 3 (STAT3) and sonic hedgehog (SHH). Thus, these pathways have become a promising target for anti‑cancer therapeutic strategies. Oleanolic acid (OA) is an active compound present in various herbal medicines, which have been used historically for the clinical treatment of various types of human malignancies, including colorectal cancer (CRC). The present study used a CRC mouse xenograft model and human umbilical vein endothelial cells (HUVECs) to evaluate the effect of OA on tumor angiogenesis and on the activation of the STAT3 and SHH signaling pathways. It was determined that OA treatment significantly inhibited tumor growth and reduced intratumoral microvessel density (MVD) in CRC mice. In addition, OA treatment inhibited the proliferation, migration and tube formation in HUVECs, in a dose and time-dependent manner. Furthermore, OA markedly suppressed the activation of the STAT3 and SHH signaling pathways and inhibited the expression of the pro‑angiogenic vascular endothelial growth factor A and basic fibroblast growth factor, two important target genes of the aforementioned signaling pathways. Therefore it is suggested that inhibition of tumor angiogenesis via the suppression of multiple signaling pathways may be one of the underlying mechanisms by which OA exerts its anti-cancer effect.

Inhibitory effects of Hedyotis diffusa Willd. on colorectal cancer stem cells

Cancer stem cells (CSCs) are proposed to be closely correlated with the development and progression of tumors, as well as with chemo- and radioresistance. Targeting CSCs may therefore be a promising potential strategy for the treatment of cancer. Currently, natural products have received great interest due to their therapeutic efficacy and reduced adverse effects compared with modern chemotherapeutics. As a significant component of a number of traditional Chinese medicine formulas, the medicinal herb Hedyotis diffusa Willd. (HDW) has long been utilized in China to clinically treat a variety of malignancies, including colorectal cancer (CRC). Previously, the authors of the present study reported that HDW suppressed CRC growth through multiple mechanisms, including promoting apoptosis, and inhibiting cell proliferation and tumor angiogenesis. To additionally investigate its mode of action, the present study isolated a stem-like side population (SP) from colorectal cancer HT-29 cells to investigate the effect of ethanol extract of HDW on CSCs. It was observed that HDW was able to markedly downregulate the expression of CSC marker leucine-rich repeat-containing G-protein coupled receptor 5 and also significantly decrease the proportion of SP in HT-29 cells, in a dose-dependent manner. Furthermore, HDW treatment significantly and dose-dependently inhibited the viability and sphere formation, and induced cell morphological changes of isolated HT-29 SP cells. In addition, HDW greatly suppressed the messenger RNA expression of several critical genes that mediate CSC features, including ATP-binding cassette, sub-family B, member 1, β-catenin, c-Myc, proliferating cell nuclear antigen and survivin. In conclusion, the present study indicates that HDW may exert inhibitory effects on cancer stem cells.

Pterostilbene carboxaldehyde thiosemicarbazone, a resveratrol derivative inhibits 17β-Estradiol induced cell migration and proliferation in HUVECs

Angiogenesis plays important roles in tumor growth and metastasis, thus development of a novel angiogenesis inhibitor is essential for the improvement of therapeutics against cancer. Thrombospondins-1 (TSP-1) is a potent endogenous inhibitor of angiogenesis that acts through direct effects on endothelial cell migration, proliferation, survival, and activating apoptotic pathways. TSP-1 has been shown to disrupt estrogen-induced endothelial cell proliferation and migration. Here we investigated the potential of pterostilbene carboxaldehyde thiosemicarbazone (PTERC-T), a novel resveratrol (RESV) derivative, to inhibit angiogenesis induced by female sex steroids, particularly 17β-Estradiol (E2), on Human umbilical vein endothelial cells (HUVECs) and to elucidate the involvement of TSP-1 in PTERC-T action. Our results showed that PTERC-T significantly inhibited 17β-E2-stimulated proliferation of HUVECs and induced apoptosis as determined by annexin V/propidium iodide staining and cleaved caspase-3 expression. Furthermore, PTERC-T also inhibited endothelial cell migration, and invasion in chick chorioallantoic membrane (CAM) assay. In contrast, RESV failed to inhibit 17β-E2 induced HUVECs proliferation and invasion at similar dose. PTERC-T was also found to increase TSP-1 protein expression levels in a dose-dependent manner which, however, was counteracted by co-incubation with p38MAPK or JNK inhibitors, suggesting involvement of these pathways in PTERC-T action. These results suggest that the inhibitory effect of PTERC-T on 17β-E2 induced angiogenesis is associated, at least in part, with its induction of endothelial cell apoptosis and inhibition of cell migration through targeting TSP-1. Thus, PTERC-T could be considered as a potential lead compound for developing a class of new drugs targeting angiogenesis-related diseases.

Potential Use of Turkish Medicinal Plants in the Treatment of Various Diseases

Medicinal plants are sources of health-promoting substances, including phytochemicals and phytoalexins that comprise polyphenols, flavonoids, carotenoids, vitamins A, C, E and several other constituents. Many studies have indicated that medicinal plants have been used to treat human diseases for thousands of years owing to their antimicrobial and antioxidant activities. Medicinal plants reduce the oxidative stress in cells and prevent cancer, cardiovascular and inflammatory diseases, neurodegenerative and digestive system disorders. These potential beneficial effects have been attributed to the presence of bioactive compounds that show antioxidant properties by acting as free radical scavengers or metal chelators, reducing the reactions that produce reactive oxygen and nitrogen species (ROS/RNS). Considering the importance of medicinal plants in terms of their beneficial health effects, some of the medicinally important plants grown in Turkey are covered in this review with respect to their antioxidant potential and phytochemical profile.

Drug activity screening based on microsomes-hydrogel system in predicting metabolism induced antitumor effect of oroxylin A

A novel microsomes-hydrogel added cell culture system (MHCCS) was employed in the antitumor activity screening of natural compounds, aiming to achieve drug screening with better in vivo correlation, higher initiative to explore the potential active metabolites, and investigation of the antitumor mechanism from the perspective of metabolism. MTT assay and cell apoptosis detection showed that test drug oroxylin A (OA) had enhanced cytotoxicity and wogonin (W) with reduced cytotoxicity on MCF-7 cell line upon MHCCS incubation. In vivo antitumor evaluations also demonstrated that OA induced higher tumor inhibition than W at the same dosage. To explore the reasons, nine major metabolites of OA were separated and collected through UPLC-Q-TOF and semi-preparative HPLC. Metabolites M318 exhibited higher cytotoxicity than OA and other metabolites by MTT assay. (1)H NMR spectrums, HPLC and TOF MS/MS results revealed that OA was catalyzed into its active metabolite M318 via a ring-opening reaction. M318 induced significant cell apoptosis and S-phase arrest through affecting tumor survival related genes after mechanism study. In conclusion, our MHCCS could be a useful tool for drug activity screening from a perspective of metabolism.

Medicinal plants used in Mexican traditional medicine for the treatment of colorectal cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Cancer cases numbers are increasing worldwide positioning this disease as the second cause of mortality for both sexes. Medicinal plants have been used in the fight against cancer as the basis for drug discovery and nowadays more than 70% of anticancer drugs have a natural origin. Mexico is regarded for its cultural and biological diversity, which is reflected in the vast traditional knowledge of herbal remedies. In this review we examined herbal remedies employed in colorectal cancer treatment (CRC).

AIM OF THE STUDY

The goal of this work was to gather scientific reports of plants used in Mexican traditional medicine for CRC treatment.

MATERIALS AND METHODS

We performed a search on scientific literature databases using as keywords: "colon cancer", "gastric cancer", "cytotoxicity", studies "in vitro and in vivo", in combination with "Mexican medicinal plants" or "Mexican herbal remedies". The selection criteria of cytotoxic activity for extracts or pure compounds was based on the National Cancer Institute of USA recommendations of effective dose 50 (ED50) of ≤20μg/mL and ≤4μg/mL, respectively.

RESULTS

In this review we report 25 botanic families and 39 species of plants used for the treatment of colon cancer in Mexico with evidence in studies in vitro and in vivo.

CONCLUSIONS

Medicinal plants are still a great source of novel chemical structures with antineoplastic potential as it is proven in this work. The selection criteria and activity was narrowed for methodological purposes, nevertheless, drug discovery of natural origin continues to be a highly attractive R&D strategy.

Nitidine chloride inhibits proliferation and induces apoptosis in colorectal cancer cells by suppressing the ERK signaling pathway

Nitidine chloride (NC) is a natural bioactive phytochemical alkaloid that has displayed anticancer activity in various types of cancer. However, no evidence has been reported for the direct effect of NC on CRC cell proliferation and apoptosis, and the underling mechanisms to be fully elucidated. The present study aimed to investigate the influence of NC on the apoptosis and proliferation of CRC cells. The viability and proliferation of CRC cells was measured by MTT assay and a [³H] thymidine uptake assay. Apoptosis was measured using a flow cytometric apoptosis assay and TUNEL staining. The expression levels of apoptotic-regulated proteins in addition to extracellular signal-regulated kinase (ERK) were measured by western blot analysis following stimulation with NC. The results indicated that NC inhibited the proliferation of HCT116 cells in a dose- and time-dependent manner. Additionally, apoptotic induction by NC treatment was confirmed. Furthermore, NC was demonstrated to significantly upregulate the expression of Bax, p53, cleaved caspase-3 and -9 and downregulate the expression of Bcl-2. Treatment with NC reduced the phosphorylation of ERK and by using an ERK inhibitor, U0126, the roles of NC in apoptotic induction and the inhibition of proliferation were further demonstrated. These results demonstrated that NC inhibited the proliferation and induced the apoptosis of CRC cells via the ERK signaling pathway.

Evaluation of Phenolic Content Variability along with Antioxidant, Antimicrobial, and Cytotoxic Potential of Selected Traditional Medicinal Plants from India

Plants have been used since ancient times as an important source of biologically active substances. The aim of the present study was to investigate the phytochemical constituents (flavonoids and phenolics), antioxidant potential, cytotoxicity against HepG2 (human hepato carcinoma) cancer cell lines, and the antimicrobial activity of the methanol extract of selected traditional medicinal plants collected from Mizoram, India. A number of phenolic compounds were detected using HPLC-DAD-ESI-TOF-MS, mainly Luteolin, Kaempferol, Myricetin, Gallic Acid, Quercetin and Rutin, some of which have been described for the first time in the selected plants. The total phenolic and flavonoid contents showed high variation ranging from 4.44 to 181.91 μg of Gallic Acid equivalent per milligram DW (GAE/mg DW) and 3.17 to 102.2 μg of Quercetin/mg, respectively. The antioxidant capacity was determined by DPPH (IC50 values ranges from 34.22 to 131.4 μg/mL), ABTS (IC50 values ranges from 24.08 to 513.4 μg/mL), and reducing power assays. Antimicrobial activity was assayed against gram positive (Staphylococcus aureus), gram negative (Escherichia coli, Pseudomonas aeruginosa), and yeast (Candida albicans) demonstrating that the methanol extracts of some plants were efficacious antimicrobial agents. Additionally, cytotoxicity was assessed on human hepato carcinoma (HepG2) cancer cell lines and found that the extracts of Albizia lebbeck, Dillenia indica, and Bombax ceiba significantly decreased the cell viability at low concentrations with IC50 values of 24.03, 25.09, and 29.66 μg/mL, respectively. This is the first report of detection of phenolic compounds along with antimicrobial, antioxidant and cytotoxic potential of selected medicinal plants from India, which indicates that these plants might be valuable source for human and animal health.

Strategies for the Optimization of Natural Leads to Anticancer Drugs or Drug Candidates

Natural products have made significant contribution to cancer chemotherapy over the past decades and remain an indispensable source of molecular and mechanistic diversity for anticancer drug discovery. More often than not, natural products may serve as leads for further drug development rather than as effective anticancer drugs by themselves. Generally, optimization of natural leads into anticancer drugs or drug candidates should not only address drug efficacy, but also improve absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiles and chemical accessibility associated with the natural leads. Optimization strategies involve direct chemical manipulation of functional groups, structure-activity relationship directed optimization and pharmacophore-oriented molecular design based on the natural templates. Both fundamental medicinal chemistry principles (e.g., bioisosterism) and state-of-the-art computer-aided drug design techniques (e.g., structure-based design) can be applied to facilitate optimization efforts. In this review, the strategies to optimize natural leads to anticancer drugs or drug candidates are illustrated with examples and described according to their purposes. Furthermore, successful case studies on lead optimization of bioactive compounds performed in the Natural Products Research Laboratories at UNC are highlighted.

New Sesquiterpene Lactone Dimer, Uvedafolin, Extracted from Eight Yacon Leaf Varieties (Smallanthus sonchifolius): Cytotoxicity in HeLa, HL-60, and Murine B16-F10 Melanoma Cell Lines

Uvedafolin, 1, a new sesquiterpene lactone dimer, was isolated from the leaves of Smallanthus sonchifolius with five related compounds, 2-6, and their cytotoxicity was assessed against three tumor cell lines (HeLa, HL-60, B16-F10 melanoma). The stereostructure of 1 was newly elucidated by ESI-TOF-MS, 1D/2D NMR, and single-crystal X-ray diffraction. Dimers 1 and 2 had the most effective IC50 values, 0.2-1.9 μM, against the three tumor cell lines when compared with monomers 3-6 (IC50 values 0.7-9.9 μM) and etoposide (IC50 values 0.8-114 μM). The ester linkages of two sets of monomers, uvedalin, 5, and sonchifolin, 6, for 1, and enhydrin, 4, and sonchifolin, 6, for 2, as well as the acetyl group at the C-9 position, were essential for the high cytotoxicity. Dimers 1 and 2 would have potential as anticancer agents.