Identification of a cytotoxic factor from a non-pigmented entomopathogenic Serratia marcescens isolate toxic towards human carcinoma cell lines.

It has been reported that cell-free culture broths and some proteins from pigmented and non-pigmented Serratia spp. are cytotoxic towards cancerous and non-cancerous human cell lines. Looking for new molecules toxic against human cancerous cells but harmless towards normal human cells, the aim of this work was (a) to determine whether cell-free broths from the entomopathogenic non-pigmented S. marcescens 81 (Sm81), S. marcescens 89 (Sm89) and S. entomophila (SeMor4.1) presented cytotoxic activity towards human carcinoma cell lines; (b) to identify and purify the associated cytotoxic factor(s) and (c) to evaluate whether the cytotoxic factor(s) was cytotoxic towards non-cancerous human cells. This research was focussed on the observed morphology changes and the proportion of remaining viable cells after incubation in the presence of cell-free culture broths from the Serratia spp isolates to evaluate cytotoxic activity. The results showed that broths from both S. marcescens isolates presented cytotoxic activity and induced cytopathic-like effects on the human neuroblastoma CHP-212 and the breast cancer MDA-MB-231 cells. Slight cytotoxicity was observed in the SeMor4.1 broth. A serralysin-like protein of 50 kDa was identified in Sm81 broth as responsible for cytotoxic activity after purification by ammonium sulphate precipitation and ion-exchange chromatography followed by tandem-mass spectrometry (LC-MS/MS). The serralysin-like protein was toxic against CHP-212 (neuroblastoma), SiHa (human cervical carcinoma) and D-54 (human glioblastoma) cell lines in a dose-dependent manner and showed no cytotoxic activity in primary cultures of normal non-cancerous human keratinocytes and fibroblasts. Therefore, this protein should be evaluated for a potential use as an anticancer agent.

Finding a Novel Chalcone-Cinnamic Acid Chimeric Compound with Antiproliferative Activity against MCF-7 Cell Line Using a Free-Wilson Type Approach.

In this work, we carried out the design and synthesis of new chimeric compounds from the natural cytotoxic chalcone 2',4'-dihydroxychalcone (2',4'-DHC, A) in combination with cinnamic acids. For this purpose, a descriptive and predictive quantitative structure-activity relationship (QSAR) model was developed to study the chimeric compounds' anti-cancer activities against human breast cancer MCF-7, relying on the presence or absence of structural motifs in the chalcone structure, like in a Free-Wilson approach. For this, we used 207 chalcone derivatives with a great variety of structural modifications over the α and ß rings, such as halogens (F, Cl, and Br), heterocyclic rings (piperazine, piperidine, pyridine, etc.), and hydroxyl and methoxy groups. The multilinear equation was obtained by the genetic algorithm technique, using logIC50 as a dependent variable and molecular descriptors (constitutional, topological, functional group count, atom-centered fragments, and molecular properties) as independent variables, with acceptable statistical parameter values (R2 = 86.93, Q2LMO = 82.578, Q2BOOT = 80.436, and Q2EXT = 80.226), which supports the predictive ability of the model. Considering the aromatic and planar nature of the chalcone and cinnamic acid cores, a structural-specific QSAR model was developed by incorporating geometrical descriptors into the previous general QSAR model, again, with acceptable parameters (R2 = 85.554, Q2LMO = 80.534, Q2BOOT = 78.186, and Q2EXT = 79.41). Employing this new QSAR model over the natural parent chalcone 2',4'-DHC (A) and the chimeric compound 2'-hydroxy,4'-cinnamate chalcone (B), the predicted cytotoxic activity was achieved with values of 55.95 and 17.86 µM, respectively. Therefore, to corroborate the predicted cytotoxic activity compounds A and B were synthesized by two- and three-step reactions. The structures were confirmed by 1H and 13C NMR and ESI+MS analysis and further evaluated in vitro against HepG2, Hep3B (liver), A-549 (lung), MCF-7 (breast), and CasKi (cervical) human cancer cell lines. The results showed IC50 values of 11.89, 10.27, 56.75, 14.86, and 29.72 µM, respectively, for the chimeric cinnamate chalcone B. Finally, we employed B as a molecular scaffold for the generation of cinnamate candidates (C-K), which incorporated structural motifs that enhance the cytotoxic activity (pyridine ring, halogens, and methoxy groups) according to our QSAR model. ADME/tox in silico analysis showed that the synthesized compounds A and B, as well as the proposed chalcones C and G, are the best candidates with adequate drug-likeness properties. From all these results, we propose B (as a molecular scaffold) and our two QSAR models as reliable tools for the generation of anti-cancer compounds over the MCF-7 cell line.

Marine Cyanobacteria as Sources of Lead Anticancer Compounds: A Review of Families of Metabolites with Cytotoxic, Antiproliferative, and Antineoplastic Effects.

The marine environment is highly diverse, each living creature fighting to establish and proliferate. Among marine organisms, cyanobacteria are astounding secondary metabolite producers representing a wonderful source of biologically active molecules aimed to communicate, defend from predators, or compete. Studies on these molecules' origins and activities have been systematic, although much is still to be discovered. Their broad chemical diversity results from integrating peptide and polyketide synthetases and synthases, along with cascades of biosynthetic transformations resulting in new chemical structures. Cyanobacteria are glycolipid, macrolide, peptide, and polyketide producers, and to date, hundreds of these molecules have been isolated and tested. Many of these compounds have demonstrated important bioactivities such as cytotoxicity, antineoplastic, and antiproliferative activity with potential pharmacological uses. Some are currently under clinical investigation. Additionally, conventional chemotherapeutic treatments include drugs with a well-known range of side effects, making anticancer drug research from new sources, such as marine cyanobacteria, necessary. This review is focused on the anticancer bioactivities of metabolites produced by marine cyanobacteria, emphasizing the identification of each variant of the metabolite family, their chemical structures, and the mechanisms of action underlying their biological and pharmacological activities.

Cytotoxic Fractions from Hechtia glomerata Extracts and p-Coumaric Acid as MAPK Inhibitors.

Preliminary bioassay-guided fractionation was performed to identify cytotoxic compounds from Hechtia glomerata, a plant that is used in Mexican ethnomedicine. Organic and aqueous extracts were prepared from H. glomerata's leaves and evaluated against two cancer cell lines. The CHCl3/MeOH (1:1) active extract was fractionated, and the resulting fractions were assayed against prostate adenocarcinoma PC3 and breast adenocarcinoma MCF7 cell lines. Active fraction 4 was further analyzed by high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry analysis to identify its active constituents. Among the compounds that were responsible for the cytotoxic effects of this fraction were flavonoids, phenolic acids, and aromatic compounds, of which p-coumaric acid (p-CA) and its derivatives were abundant. To understand the mechanisms that underlie p-CA cytotoxicity, a microarray assay was performed on PC3 cells that were treated or not with this compound. The results showed that mitogen-activated protein kinases (MAPKs) that regulate many cancer-related pathways were targeted by p-CA, which could be related to the reported effects of reactive oxygen species (ROS). A molecular docking study of p-CA showed that this phenolic acid targeted these protein active sites (MAPK8 and Serine/Threonine protein kinase 3) at the same binding site as their inhibitors. Thus, we hypothesize that p-CA produces ROS, directly affects the MAPK signaling pathway, and consequently causes apoptosis, among other effects. Additionally, p-CA could be used as a platform for the design of new MAPK inhibitors and re-sensitizing agents for resistant cancers.

Metabolic Profile and Evaluation of Biological Activities of Extracts from the Stems of Cissus trifoliata.

Cissus trifoliata (L.) L belongs to the Vitaceae family and is an important medicinal plant used in Mexico for the management of infectious diseases and tumors. The present study aimed to evaluate the metabolic profile of the stems of C. trifoliata and to correlate the results with their antibacterial and cytotoxic activities. The hexane extract was analyzed using gas chromatography coupled with mass spectrometry (GC-MS) and the CHCl3-MeOH and aqueous extracts by ultraperformance liquid chromatography quadrupole time of fly mass spectrometry (UPLC-QTOF-MS). The antibacterial activity was determined by broth microdilution and the cytotoxicity was evaluated using MTS cell proliferation assay. Forty-six metabolites were putatively identified from the three extracts. Overall, terpenes, flavonoids and stilbenes characterize the metabolic profile. No antibacterial activity was found in any extract against the fifteen bacteria strains tested (MIC >500 µg/mL). However, high cytotoxic activity (IC50 ≤ 30 µg/mL) was found in the hexane and aqueous extracts against hepatocarcinoma and breast cancer cells (Hep3B, HepG2 and MCF7). This is the first report of the bioactive compounds of C. trifoliata stems and their antibacterial and cytotoxic properties. The metabolic profile rich in anticancer compounds correlate with the cytotoxic activity of the extracts from the stems of C. trifoliata. This study shows the antitumor effects of this plant used in the traditional medicine and justifies further research of its anticancer activity.

Explaining the larger seed bank of an invasive shrub in non-native versus native environments by differences in seed predation and plant size.

BACKGROUND AND AIMS: Large, persistent seed banks contribute to the invasiveness of non-native plants, and maternal plant size is an important contributory factor. We explored the relationships between plant vegetative size (V) and soil seed bank size (S) for the invasive shrub Ulex europaeus in its native range and in non-native populations, and identified which other factors may contribute to seed bank variation between native and invaded regions. METHODS: We compared the native region (France) with two regions where Ulex is invasive, one with seed predators introduced for biological control (New Zealand) and another where seed predators are absent (La Réunion). We quantified seed bank size, plant dimensions, seed predation and soil fertility for six stands in each of the three regions. KEY RESULTS: Seed banks were 9-14 times larger in the two invaded regions compared to native France. We found a positive relationship between current seed bank size and actual plant size, and that any deviation from this relationship was probably due to large differences in seed predation and/or soil fertility. We further identified three possible factors explaining larger seed banks in non-native environments: larger maternal plant size, lower activity of seed predators and higher soil fertility. CONCLUSIONS: In highlighting a positive relationship between maternal plant size and seed bank size, and identifying additional factors that regulate soil seed bank dynamics in non-native ranges, our data offer a number of opportunities for invasive weed control. For non-native Ulex populations specifically, management focusing on 'S' (i.e. the reduction of the seed bank by stimulating germination, or the introduction of seed predators as biological control agents) and/or on 'V' (i.e. by cutting mature stands to reduce maternal plant biomass) offers the most probable combination of effective control options.

Design, synthesis and QSAR study of 2'-hydroxy-4'-alkoxy chalcone derivatives that exert cytotoxic activity by the mitochondrial apoptotic pathway.

Eleven 4'-alkoxy chalcones were synthesized and biologically evaluated for their antiproliferative activity against four human tumor cell lines (PC-3, MCF-7, HF-6, and CaSki). Compounds 3a-3d and 3f were selective against PC-3, with IC50 values ranging from 8.08 to 13.75 µM. In addition, chalcones 3a-3c did not affect the normal fibroblasts BJ cells. The most active and selective compounds were further evaluated for their effect on the progression of cell cycle in PC-3 cells, and chalcones 3a and 3c induced a G2/M phase arrest. Furthermore, it was found that these three chalcones induced the mitochondrial apoptotic pathway by regulating Bax and Bcl-2 transcripts and by increasing caspase 3/7 activation. Otherwise, the QSAR model indicates that the double bond of the α,ß-unsaturated carbonyl, as well as the planar structure geometry, are important to the biological activity of the synthetized chalcones. Based on these studies, it was concluded that withdrawing substituents in ring A, decrease the antiproliferative activity. This is related to the possible mechanism of action of these compounds, where a Michael addition needs to take place in order to be a potent anticancer agent.

16-Hydroxy-Lycopersene, a Polyisoprenoid Alcohol Isolated from Tournefortia hirsutissima, Inhibits Nitric Oxide Production in RAW 264.7 Cells and Induces Apoptosis in Hep3B Cells.

Three polyisoprenoid alcohols were isolated from the leaves of Tournefortia hirsutissima by a bioassay-guided phytochemical investigation. The compounds were identified as 16-hydroxy-lycopersene (Compound 1), (Z8,E3,ω)-dodecaprenol (Compound 2) and (Z9,E3,ω)-tridecaprenol (Compound 3). Compound 1, an unusual polyisoprenoid, was characterized by 1D and 2D NMR. We also determined the absolute configuration at C-16 by the modified Mosher's method. The in vitro antiproliferative and anti-inflammatory activities of the isolated compounds were evaluated. Among isolates, Compound 1 moderately inhibited the nitric oxide production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. On the other hand, Compound 1 displayed selective antiproliferative activity against HeLa, PC3, HepG2 and Hep3B cancer cells and was less potent against IHH non-cancerous cells. Compound 1 in Hep3B cells showed significant inhibition of cell cycle progression increasing the sub-G1 phase, suggesting cell death. Acridine orange/ethidium bromide staining and Annexin V-FITC/PI staining demonstrated that cell death induced by Compound 1 in cells Hep3B was by apoptosis. Further study showed that apoptosis induced by Compound 1 in Hep3b cells is associated with the increase of the ratio of Bax/Bcl-2, and caspase 3/7 activation. These results suggest that Compound 1 induce apoptotic cell death by the mitochondrial pathway. To our knowledge, this is the first report about the presence of polyprenol Compounds 1-3 in T. hirsutissima, and the apoptotic and anti-inflammatory action of Compound 1.

Genetic determinants of childhood and adult height associated with osteosarcoma risk.

BACKGROUND: Although increased height has been associated with osteosarcoma risk in previous epidemiologic studies, to the authors' knowledge the relative contribution of stature during different developmental timepoints remains unclear. Furthermore, the question of how genetic determinants of height impact osteosarcoma etiology remains unexplored. Genetic variants associated with stature in previous genome-wide association studies may be biomarkers of osteosarcoma risk. METHODS: The authors tested the associations between osteosarcoma risk and polygenic scores for adult height (416 variants), childhood height (6 variants), and birth length (5 variants) in 864 osteosarcoma cases and 1879 controls of European ancestry. RESULTS: Each standard deviation increase in the polygenic score for adult height, corresponding to a 1.7-cm increase in stature, was found to be associated with a 1.10-fold increase in the risk of osteosarcoma (95% confidence interval [95% CI], 1.01-1.19; P =.027). Each standard deviation increase in the polygenic score for childhood height, corresponding to a 0.5-cm increase in stature, was associated with a 1.10-fold increase in the risk of osteosarcoma (95% CI, 1.01-1.20; P =.023). The polygenic score for birth length was not found to be associated with osteosarcoma risk (P =.11). When adult and childhood height scores were modeled together, they were found to be independently associated with osteosarcoma risk (P =.037 and P = .043, respectively). An expression quantitative trait locus for cartilage intermediate layer protein 2 (CILP2), rs8103992, was significantly associated with osteosarcoma risk after adjustment for multiple comparisons (odds ratio, 1.35; 95% CI, 1.16-1.56 [P = 7.93×10-5 and Padjusted =.034]). CONCLUSIONS: A genetic propensity for taller adult and childhood height attainments contributed independently to osteosarcoma risk in the current study data. These results suggest that the biological pathways affecting normal bone growth may be involved in osteosarcoma etiology.

Competition along productivity gradients: news from heathlands.

The importance of competition in low productive habitats is still debated. Studies which simultaneously evaluate preemption of resources and consequences for population dynamics are needed for a comprehensive view of competitive outcomes. We cultivated two emblematic species of European heathlands (Calluna vulgaris and Molinia caerulea) in a nursery for 2 years at two fertility levels, reproducing the productivity gradient found in phosphorus (P)-depleted heathlands in southwest France. The second year, we planted Ulex europaeus seedlings, a ubiquitous heathland species, under the cover of the two species to evaluate its ability to regenerate. Half of the seedlings were placed in tubes for exclusion of competitor roots. We measured the development of the competitors aboveground and belowground and their interception of resources (light, water, inorganic P). Ulex seedlings' growth and survival were also measured. Our results on resources interception were consistent with species distribution in heathlands. Molinia, which dominates rich heathlands, was the strongest competitor for light and water in the rich soil. Calluna, which dominates poor heathlands, increased its root allocation in the poor soil, decreasing water and inorganic P availability. However, the impact of total competition and root competition on Ulex seedlings decreased in the poor soil. Other mechanisms, especially decrease of water stress under neighbouring plant cover, appeared to have more influence on the seedlings' response. We found no formal contradiction between Tilman and Grime's theories. Root competition has a primary role in acquisition of soil resources in poor habitats. However, the importance of competition decreases with decreasing fertility.

Lignans from Bursera fagaroides Affect In Vivo Cell Behavior by Disturbing the Tubulin Cytoskeleton in Zebrafish Embryos.

By using a zebrafish embryo model to guide the chromatographic fractionation of antimitotic secondary metabolites, seven podophyllotoxin-type lignans were isolated from a hydroalcoholic extract obtained from the steam bark of Bursera fagaroides. The compounds were identified as podophyllotoxin (1), ß-peltatin-A-methylether (2), 5'-desmethoxy-ß-peltatin-A-methylether (3), desmethoxy-yatein (4), desoxypodophyllotoxin (5), burseranin (6), and acetyl podophyllotoxin (7). The biological effects on mitosis, cell migration, and microtubule cytoskeleton remodeling of lignans 1⁻7 were further evaluated in zebrafish embryos by whole-mount immunolocalization of the mitotic marker phospho-histone H3 and by a tubulin antibody. We found that lignans 1, 2, 4, and 7 induced mitotic arrest, delayed cell migration, and disrupted the microtubule cytoskeleton in zebrafish embryos. Furthermore, microtubule cytoskeleton destabilization was observed also in PC3 cells, except for 7. Therefore, these results demonstrate that the cytotoxic activity of 1, 2, and 4 is mediated by their microtubule-destabilizing activity. In general, the in vivo and in vitro models here used displayed equivalent mitotic effects, which allows us to conclude that the zebrafish model can be a fast and cheap in vivo model that can be used to identify antimitotic natural products through bioassay-guided fractionation.

Phenolic Compounds Isolated from Caesalpinia coriaria Induce S and G2/M Phase Cell Cycle Arrest Differentially and Trigger Cell Death by Interfering with Microtubule Dynamics in Cancer Cell Lines.

Caesalpinia coriaria (C. coriaria), also named cascalote, has been known traditionally in México for having cicatrizing and inflammatory properties. Phytochemical reports on Caesalpinia species have identified a high content of phenolic compounds and shown antineoplastic effects against cancer cells. The aim of this study was to isolate and identify the active compounds of a water:acetone:ethanol (WAE) extract of C. coriaria pods and characterize their cytotoxic effect and cell death induction in different cancer cell lines. The compounds isolated and identified by chromatography and spectroscopic analysis were stigmasterol, ethyl gallate and gallic acid. Cytotoxic assays on cancer cells showed different ranges of activities. A differential effect on cell cycle progression was observed by flow cytometry. In particular, ethyl gallate and tannic acid induced G2/M phase cell cycle arrest and showed interesting effect on microtubule stabilization in Hep3B cells observed by immunofluorescence. The induction of apoptosis was characterized by morphological characteristic changes, and was supported by increases in the ratio of Bax/Bcl-2 expression and activation of caspase 3/7. This work constitutes the first phytochemical and cytotoxic study of C. coriaria and showed the action of its phenolic constituents on cell cycle, cell death and microtubules organization.

Tiger salamanders' (Ambystoma tigrinum) response learning and usage of visual cues.

We explored tiger salamanders' (Ambystoma tigrinum) learning to execute a response within a maze as proximal visual cue conditions varied. In Experiment 1, salamanders learned to turn consistently in a T-maze for reinforcement before the maze was rotated. All learned the initial task and executed the trained turn during test, suggesting that they learned to demonstrate the reinforced response during training and continued to perform it during test. In a second experiment utilizing a similar procedure, two visual cues were placed consistently at the maze junction. Salamanders were reinforced for turning towards one cue. Cue placement was reversed during test. All learned the initial task, but executed the trained turn rather than turning towards the visual cue during test, evidencing response learning. In Experiment 3, we investigated whether a compound visual cue could control salamanders' behaviour when it was the only cue predictive of reinforcement in a cross-maze by varying start position and cue placement. All learned to turn in the direction indicated by the compound visual cue, indicating that visual cues can come to control their behaviour. Following training, testing revealed that salamanders attended to stimuli foreground over background features. Overall, these results suggest that salamanders learn to execute responses over learning to use visual cues but can use visual cues if required. Our success with this paradigm offers the potential in future studies to explore salamanders' cognition further, as well as to shed light on how features of the tiger salamanders' life history (e.g. hibernation and metamorphosis) impact cognition.

Serum leptin is associated with metabolic syndrome in obese Mexican subjects.

BACKGROUND: The metabolic syndrome (MetS) is a cluster of metabolic abnormalities including insulin resistance, dyslipidemia, high blood pressure, and abdominal adiposity. Obese patients develop leptin resistance, and an increased waist circumference (WC) due to deposition of abdominal fat. The aim of this study was to evaluate the association between circulating leptin levels and MetS among sample adult Mexican workers. METHOD: A total of 204 workers aged 20-56 were evaluated. Anthropometric index, blood pressure, fasting plasma glucose, and lipid profile were measured by spectrophotometric methods. Fasting insulin and leptin were measured by inmunoenzimatic methods. Furthermore, homeostasis model assessment for insulin resistance (HOMA-IR) was calculated. RESULTS: The prevalence of MetS according to the ATP-III criteria was 33.8% and leptin concentrations were 2.5 times higher in women than men. Subjects with MetS had higher levels of leptin (26.7 ± 13.7) compared with those without MetS (20.1 ± 13.9; P <0.001). Leptin increased significantly while BMI increased as well (normal 14.0 ± 8.9, overweight 22.7 ± 11.7 and obese 31.4 ± 14.6) in addition to other variables such as WC, HDL-C, insulin levels, and HOMA index. Each component of MetS was stratified by sex and submitted by linear regression with a 95% of accuracy. The 50% and 53% of the BMI is explained by the concentration of leptin in men and women, respectively (P < 0.001). CONCLUSION: This study found that leptin was associated with the MetS, especially in obesity and insulin resistance, indicating a high risk for university workers to develop hypertension, DM2, and cardiovascular disease.

Preserving the spots: Jaguar (Panthera onca) distribution and priority conservation areas in Colombia.

The jaguar (Panthera onca) is a charismatic species considered Vulnerable in Colombia but yet largely unknown in the country. The species is mostly threatened by the continuous decline in its habitats, mostly derived from deforestation and habitat loss, additional to hunting and conflicts with humans. Thus, the future of jaguars in Colombia depends on protecting and recovering existing habitats. The aims of this study were to 1) evaluate jaguar distribution and identify the remnant patches of habitat in Colombia, 2) define an ecological connectivity network within the country, and 3) propose a priority areas portfolio for the conservation and recovery of jaguars. We used a presence background model for estimating species potential distribution and subsequently identified remaining habitat patches across the country based on land cover and species-specific ecological attributes. We then created an ecological connectivity network based on circuit theory and following a multi-criteria approach identified jaguar priority areas for conservation (JPCA) and recovery (JPRA). Jaguar potential distribution comprises 1103122.43 km2, from which 56.71% maintain suitable patches of potential habitat. We identified 960 corridors between remnant patches of natural or semi-natural vegetation. Based on the criteria, JPCAs with greater importance were identified in each of the five Colombian regions. JPRAs were located mainly towards the Andean and Caribbean regions. These JPCAs and JPRAs could serve as a guide for designing and implementing management strategies for the long-term conservation and recovery of the species in Colombia.

Phytochemical Profiles and Cytotoxic Activity of Bursera fagaroides (Kunth) Engl. Leaves and Its Callus Culture.

Bursera fagaroides, popularly used in México, possesses bioactive lignans. These compounds are low in the bark, and its extraction endangers the life of the trees. The aim of the present investigation was to search for alternative sources of cytotoxic compounds in B. fagaroides prepared as leaves and in vitro callus cultures. The friable callus of B. fagaroides was established using a combination of plant growth regulators: 4 mgL-1 of 2,4-dichlorophenoxyacetic acid (2,4-D), 1 mgL-1 Naphthaleneacetic Acid (NAA) and 1 mgL-1 Zeatin. The maximum cell growth was at day 28 with a specific growth rate of µ = 0.059 days-1 and duplication time td = 11.8 days. HPLC quantification of the dichloromethane callus biomass extract showed that Scopoletin, with a concentration of 10.7 µg g-1 dry weight, was the main compound inducible as a phytoalexin by the addition of high concentrations of 2,4-D, as well as by the absence of nutrients in the culture medium. In this same extract, the compounds γ-sitosterol and stigmasterol were also identified by GC-MS analysis. Open column chromatography was used to separate and identify yatein, acetyl podophyllotoxin and 7',8'-dehydropodophyllotoxin in the leaves of the wild plant. Cytotoxic activity on four cancer cell lines was tested, with PC-3 prostate carcinoma (IC50 of 12.6 ± 4.6 µgmL-1) being the most sensitive to the wild-type plant extract and HeLa cervical carcinoma (IC50 of 72 ± 5 µgmL-1) being the most sensitive to the callus culture extract.

Correction: Beyond words: From jaguar population trends to conservation and public policy in Mexico.

[This corrects the article DOI: 10.1371/journal.pone.0255555.].

Exploring the Gallic and Cinnamic Acids Chimeric Derivatives as Anticancer Agents over HeLa Cell Line: An in silico and in†vitro Study.

Cervical cancer is one of the most aggressive and important cancer types in the female population, due to its low survival rate. Actually, the search for new bioactive compounds, like gallic and cinnamic acid, is one of the most employed options to finding a treatment. In the present study, 134 phenolic compounds with cytotoxic activity over HeLa cell line were used to generate a descriptive ( R 2 ${{R}^{2}}$ =0.76) and predictive ( Q 2 ${{Q}^{2}}$ =0.69 and Q e x t 2 ${{Q}_{{\rm e}{\rm x}{\rm t}}^{2}}$ =0.62) QSAR model. Structural, electronic, steric, and hydrophobic features are represented as different molecular descriptors in our QSAR model. From this model, nine gallate-cinnamate ester derivatives (N1-N9) were designed and synthesized. Furthermore, in vitro cytotoxic activity was evaluated against HeLa and non-tumorigenic cells. Derivatives N6, N5, N1, and N9 were the most active molecules with IC50ExpHeLa values from 7.26 to 11.95 µM. Finally, the binding of the synthesized compounds to the colchicine binding site on tubulin was evaluated by molecular docking as a possible action mechanism. N1, N5 and N6 can be considered as templates for the design of new cervical anticancer compounds.

Tannic Acid and Ethyl Gallate Potentialize Paclitaxel Effect on Microtubule Dynamics in Hep3B Cells.

Among broad-spectrum anticancer agents, paclitaxel (PTX) has proven to be one of the most effective against solid tumors for which more specific treatments are lacking. However, drawbacks such as neurotoxicity and the development of resistance reduce its therapeutic efficacy. Therefore, there is a need for compounds able to improve its activity by synergizing with it or potentiating its effect, thus reducing the doses required. We investigated the interaction between PTX and tannins, other compounds with anticancer activity known to act as repressors of several proteins involved in oncological pathways. We found that both tannic acid (TA) and ethyl gallate (EG) strongly potentiate the toxicity of PTX in Hep3B cells, suggesting their utility in combination therapy. We also found that AT and EG promote tubulin polymerization and enhance the effect of PTX on tubulin, suggesting a direct interaction with tubulin. Biochemical experiments confirmed that TA, but not EG, binds tubulin and potentiates the apparent binding affinity of PTX for the tubulin binding site. Furthermore, the molecular docking of TA to tubulin suggests that TA can bind to two different sites on tubulin, one at the PTX site and the second at the interface of α and ß-tubulin (cluster 2). The binding of TA to cluster 2 could explain the overstabilization in the tubulin + PTX combinatorial assay. Finally, we found that EG can inhibit PTX-induced expression of pAkt and pERK defensive protein kinases, which are involved in resistance to PXT, by limiting cell death (apoptosis) and favoring cell proliferation and cell cycle progression. Our results support that tannic acid and ethyl gallate are potential chemotherapeutic agents due to their potentiating effect on paclitaxel.

Biogeography of terrestrial vertebrates and its conservation implications in a transitional region in western Mexico.

Conservation biogeography, which applies principles, theories, and analyses of biodiversity distribution patterns to address conservation challenges, can provide valuable insight and guidance to policy making for protection of biodiversity at multiple scales. The temperate and tropical ecosystems of the Nearctic-Neotropical transition in the small western state of Colima, Mexico, support a mosaic of remarkably diverse fauna and flora and provide a rare opportunity to determine spatial distribution patterns of terrestrial vertebrate species, assess human-induced threats, and identify potential conservation strategies. We analyzed the spatial distribution patterns and correlated them with the current land cover and extent of the protected areas. Despite its limited geographic extension, 29% (866) of all vertebrates, and almost a quarter of both endemic and threatened species in Mexico, live in Colima. Our analysis identified clear high-richness concentration sites (i.e., "hotspots") coincident for all groups and that elevation and both temperate and tropical ecosystems composition exert significant influence on richness patterns. Furthermore, current species´ distribution also showed significant correlation with natural and disturbed landcover. Significant hotspots for all species groups coincided poorly with the limited protected areas in the state (only 3.8%). The current state of natural land cover (less than 16%) in the state, coupled with its remarkable biological importance, highlights the need for further complementary conservation efforts including expansion and creation of new protected areas, significant restoration efforts and other conservation measures to maintain this uniquely biogeographic and biological diverse region of the country.