A Sox2–Sox9 signalling axis maintains human breast luminal progenitor and breast cancer stem cells

Increased cancer stem cell content during development of resistance to tamoxifen in breast cancer is driven by multiple signals, including Sox2-dependent activation of Wnt signalling. Here, we show that Sox2 increases and estrogen reduces the expression of the transcription factor Sox9. Gain and loss of function assays indicate that Sox9 is implicated in the maintenance of human breast luminal progenitor cells. CRISPR/Cas knockout of Sox9 reduces growth of tamoxifen-resistant breast tumours in vivo. Mechanistically, Sox9 acts downstream of Sox2 to control luminal progenitor cell content and is required for expression of the cancer stem cell marker ALDH1A3 and Wnt signalling activity. Sox9 is elevated in breast cancer patients after endocrine therapy failure. This new regulatory axis highlights the relevance of SOX family transcription factors as potential therapeutic targets in breast cancer

Recopilación de métodos analíticos para la caracterización y determinación del quitosano y las principales aplicaciones del polímero en los envases activos alimentarios

Antimicrobial films for food packaging applications have received increasing attention from the industry in recent years. Due to their exceptional properties, such as non-toxicity, biodegradability, antimicrobial characteristics, and biocompatibility, chitosan has proven useful for the development of active materials. This review aims to provide anoverview of the main techniques used for the characterization of chitin and chitosan, including Fourier transforminfrared spectroscopy (FTIR), 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, UV spectrophotometry, viscosimetry, elemental analysis, X-ray diffraction (XRD), thermogravimetric analysis (TGA), titrations, scanning electron microscopy (SEM) and size exclusion chromatography (SEC) among others. In addition, the main applications of the polymer in food packaging are also reportedEn los últimos años los films antimicrobianos han recibido una gran atención por parte de la industria para su aplicación en el envasado alimentario. Debido a sus excepcionales propiedades, no-tóxico, biodegradable, características antimicrobianas y biocompatible, el quitosano ha demostrado ser útil para el desarrollo de materiales activos. Este artículo de revisión tiene por objeto proporcionar una visión general de las principales técnicas usadas para la caracterización de quitina y quitosano incluidas la espectroscopia infrarroja (FTIR), la espectroscopia RMN de 1H y 13C, la espectrofotometría UV, viscosimetría, análisis elemental, difracción de rayos-X (XRD), análisis termogravimétrico (TGA), titulaciones, microscopía electrónica de barrido (SEM) y cromatografía de exclusión por tamaños (SEC)entre otras. Además, se describen las principales aplicaciones del polímero en el envasado de los alimentosThis work was funded under the Project no. 95935 from FONCICYT C002-2008-1/ALA 127 249S

SOX11 promotes epithelial/mesenchymal hybrid state and alters tropism of invasive breast cancer cells.

SOX11 is an embryonic mammary epithelial marker that is normally silenced prior to birth. High SOX11 levels in breast tumours are significantly associated with distant metastasis and poor outcome in breast cancer patients. Here, we show that SOX11 confers distinct features to ER-negative DCIS.com breast cancer cells, leading to populations enriched with highly plastic hybrid epithelial/mesenchymal cells, which display invasive features and alterations in metastatic tropism when xenografted into mice. We found that SOX11+DCIS tumour cells metastasize to brain and bone at greater frequency and to lungs at lower frequency compared to cells with lower SOX11 levels. High levels of SOX11 leads to the expression of markers associated with mesenchymal state and embryonic cellular phenotypes. Our results suggest that SOX11 may be a potential biomarker for breast tumours with elevated risk of developing metastases and may require more aggressive therapies

Compilation of analytical methods to characterize and determine chitosan, and main applications of the polymer in food active packaging

Antimicrobial films for food packaging applications have received increasing attention from the industry in recent years. Due to their exceptional properties, such as non-toxicity, biodegradability, antimicrobial characteristics, and biocompatibility, chitosan has proven useful for the development of active materials. This review aims to provide an overview of the main techniques used for the characterization of chitin and chitosan, including Fourier transform infrared spectroscopy (FTIR), 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, UV spectrophotometry, viscosimetry, elemental analysis, X-ray diffraction (XRD), thermogravimetric analysis (TGA), titrations, scanning electron microscopy SEM) and size exclusion chromatography (SEC) among others. In addition, the main applications of the polymer in food packaging are also reported.This work was funded under the Project no. 95935 from FONCICYT C002-2008-1/ALA 127 249

Characterization of chitosan intended to develop antimicrobial films: Microscopical Studies

Accumulation of organic wastes in intensive crustaceans culture ponds and nearby coastal waters has become a serious environmental and economical problem. For this reason, new ecofriendly and economically feasible products from agricultural wastes or byproducts for shrimp farms have been developed. This biowaste could be used as an important source of the useful biopolymer chitin and others components such as proteins or carotenoids like asthaxanthin [1]. Chitin is the most abundant polysaccharide after cellulose and the main source is the shell of crustaceans. Chitosan, derived from chitin, has proven useful for a wide range of applications due to its biodegradability, biocompatibility, antimicrobial activity, non-toxicity and versatile physicochemical properties. These properties make the chitosan an excellent candidate to use in food packaging [2]. The development of active packaging with antimicrobial and antioxidant activity based on chitosan and asthaxanthin obtained from shrimp waste is the main goal of the project: “Preparation of active packaging with antioxidant and antimicrobial activity based on asthaxanthin and chitosan” funded by FONCYCIT. The characterization of chitosan in the development of active materials is a key issue since their properties play an important role in its effectiveness as an antimicrobial agent. These properties are mainly molecular weight (Mw), acetylation degree (DA) and polymerization degree (PA). In addition, in mediums of low pH, the antimicrobial activity of chitosan increases [3]. The objective of the present study was characterized three different samples of chitosan obtained from shrimp waste by using two microscopy techniques, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Additionally, the films developed after the chitosan incorporation in the polyamide matrix were also characterized. Shrimp waste (heads and cephalotorax) samples were collected from local shrimp processing factories in South Sonora, Mexico. The waste was minced, fermented and centrifuged. After the treatment, three fractions were obtained: chitin-rich fraction, protein rich liquor and lipid fraction. Scanning Electron Microscopy was used to investigate the structure properties relationships of chitosan. Samples were spread on a carbon conducting adhesive tape pasted on a metallic stub, subjected to gold covering and observed. The samples for TEM observation were embedded in EPON resin and polymerized at 60 ºC; then were cut at (-120 ºC) using a Leica Ultracut crio-ultramicrotome. The images obtained showed the particle of chitosan embedded into the polyamide matrix.FONCYCIT (Fund for International Cooperation of Science and Technology EU-Mexico

Preparation and Characterization of Antimicrobial Films Based on Chitosan for Active Food Packaging Applications

The aim of this paper was to characterize chitosan samples from the shrimp shells for the later development of antimicrobial active systems. These systems include 100 % chitosan-based films obtained by casting, polyamide films with 5 and 10 % of chitosan obtained by extrusion and polyethylene/polyethylene terephthalate films with a coating of 0.6 % of chitosan. For that purpose, several analytical techniques including IR, 1H NMR, GPC, and microscopic techniques (scanning electron microscopy and transmission electron microscopy) were used. Within the studied samples, C1 showed the lowest DA and MW and consequently presented the most suitable properties for the development of an active packaging. Additionally, mechanical properties were performed. The effectiveness of the developed systems was evaluated by means of microbiological assays. The tested films showed antimicrobial capacity against coliform enterobacteria, mesophilic aerobic microorganism, and yeast and moulds.This work was funded under Project no. 95935 from FONCICYT C002-2008-1/ALA 127 249. The authors are grateful to “Ministerio de Economía y Competitividad” for the Predoctoral fellowship FPI (Ref. BES-2012-051993) awarded to Miguel Ángel Lago. Raquel Sendón is grateful to the “Parga Pondal” program financed by Consellería de Innovación e Industria, Xunta de Galicia” for her postdoctoral contract

Characterization of chitosan meant for antimicrobial food packaging

Chitosan (CAS nº 9012-76-4) is a natural polysaccharide obtained by the partial deacetylation of chitin. It is a linear polymer of β (1-4) 2-acetamido-2-deoxy-D-glucose and 2-amino-2-deoxy-D-glucose in different proportions. Chitin is the most abundant polysaccharide after cellulose and the main source is the shells of crustaceans. It has been demonstrated that some important properties are directly related to the antimicrobial activity of chitosan. Some of these properties are the molecular weight (Mw), the degree of polymerisation (DP) and the degree of deacetylation (DD). In this work several analytical techniques (FTIR (Fourier-transform Infrared Spectroscopy), NMR (Nuclear Magnetic Resonance Spectroscopy) and SEM (Scanning Electron Microscopy)) were attempted to characterize two different samples obtained from shrimp waste. It can be concluded that sample 1 should be more suitable to be added as an active agent to a film.This work was funded under Project ‘Preparation of active packaging with antioxidant and antimicrobial activity based on astaxanthin and chitosan’ (PAPAAABAC, in Spanish PEACAABAQ) no. 95935 from FONCICYT C002-2008-1/ALA – 127 24

Preparation, characterization and evaluation by FTIR and NMR of antimicrobial activity of chitosan active films

One of the main causes of food spoilage is the development of microorganisms. In order to inhibit or retard the growth of microorganisms and consequently, improve food security and extend the shelf life of food products, in the past years, active packaging and particularly films with antimicrobial properties have attracted the attention of the scientists. One of the approaches used is to add chitosan to the film. Due to their excellent properties, non-toxic, biodegradable, biofunctional and biocompatible with others antimicrobials, chitosan is one of the antimicrobial agents most appropriate for the development of active materials [1]. Chitosan (CAS nº 9012-76-4) is a polysaccharide, with the structure of a linear polymer of (1-4)-linked 2-amino-deoxy-β-D-glucan, obtained by the partial deacetylation of chitin, one of the most abundant polysaccharides in nature, found in shells of crustaceans [2]. Shrimp waste (heads and cephalothorax) samples were collected from local shrimp processing factories in South Sonora, Mexico. The waste was minced, fermented and centrifuged. After the treatment, three fractions were obtained: chitin rich fraction, protein rich liquor and lipid fraction. In this work, Fourier Transformed Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) were used to characterize three different samples of chitosan. Moreover, 100% chitosan-based films and films of polyamide with chitosan incorporated were also evaluated. The degree of acetylation (DA) values obtained may change, depending on the nature and level of impurities, source and polymer morphologies [3]. To evaluate the DA, FTIR and NMR were used. The samples were prepared as a thin pellet made from a mixture of KBr and the chitosan powder. To evaluate the DA in films, Fourier Transform Total Reflection infrared Spectroscopy (FTIR-ATR) was used. All spectra were recorded in the range of 400-4000 cm-1. Nuclear Magnetic Resonance (NMR) was also employed to evaluate the DA. Two experiments were tentatively carried out: 1H NMR and 13C NMR. In both cases approximately 5 mg of each sample were diluted in 1 % (v/v) CD3COOD in D2O. All data were compared with three commercially available standards submitted to the same experiments as samples. The sample 1 corresponding to chitosan obtained from shrimp waste and with high viscosity presented the lowest DA, therefore had higher antimicrobial activity. Both techniques; FTIR and NMR, led to the same conclusion.FONCICYT (Fund for International Cooperation of Science and Technology EU-Mexico

Activity of chitosan films against different microorganisms

Chitosan is a hydrophilic polysaccharide which derives from chitin by deacetylation. It has several applications, namely as a film that can be applied to preserve the quality and increase the shelf-life of food. Chitosan is insoluble in most solvents but it is soluble in dilute organic acids such as formic acid and acetic acid[1]. The properties of chitosan depend on the degree of deacetylation (DA) and molecular weight (MW). A broad antimicrobial activity has been attributed to chitosan, either for gram-negative, gram-positive bacteria and fungi. The aim of the present study is to evaluate the antimicrobial activity of a chitosan film prepared by casting. The chitosan was obtained from shrimp waste collected from shrimp processing factories of South Sonora (Mexico). Four bacteria (Bacillus cereus; Escherichia coli; Staphylococcus aureus and Listeria monocytogenes) and one fungus (Botrytis cinerea) were evaluated. Although L. monocytogenes and B. cinerea growth was not inhibited by the chitosan film, results showed a clear growth-inhibitory effect, at the two bacteria concentration levels tested, for B. Cereus, E. coli and S. aureus. Different antibacterial mechanisms have been proposed to explain chitosan antimicrobial activity[2-3]: i) chitosan may form an external barrier which inhibits essential nutrients adsorption; ii) chitosan can also penetrate the microbial cell, disturbing the metabolism of the cell by inhibiting the mRNA and protein synthesis; iii) chitosan may have an ionic surface interaction with the bacteria originating wall cell leakage. Although these mechanisms may take place simultaneously, the antimicrobial activity may also depend on the properties of chitosan (DA and MW).This work was carried out under the Project no. 95935 from FONCICYT C002-2008-1/ ALA – 127 249, with the financial support of the European Union and CONACYT. The authors are grateful to the postdoctoral contract of Ana Sanches Silva in the frame of the Program ‘‘Science 2007’’ funded by “Fundação para a Ciência e a Tecnologia’’, Portugal