Current Pharmaceutical Biotechnology - Volume 13, Issue 15, 2012

Success in cancer chemotherapy relies on efficient delivery of anti-neoplastic drugs, with minimal side-effects on non-cancerous cells. Nanoparticulation of prospective anti-cancer drugs, that were deemed unsuitable due to short biological half life, poor water solubility and low cellular permeability, has been hypothesized to generate superior chemotherapeutic agents, leading to reduced non-specific action and fewer side-effects. In lieu of the above, different synthetic modulations on the putative anti-cancer compound andrographolide (AG) were explored to improve its therapeutic efficiency. Our results indicated that PLGA-nanoparticulation of andrographolide diterpenoid enhanced its anti-cancer properties three fold. Chitosan coating of AG nanoparticles further accentuated cellular localization, induced G1 cell cycle arrest and increased cellular toxicity and apoptosis in MCF-7 cells. The charge modulated nanoparticles were seen to traverse more efficiently through the cytoplasm and accumulate in the nucleus, thus enhancing their anti-proliferative efficacy. In vivo studies confirm that the nanoparticles reduced tumor weight by 68.21% as compared to 24.7% by AG, and increased the life span of mice infected with Ehrlich ascites carcinoma (EAC) by 78.08% as compared to 23.5% for AG alone. This was achieved through development of slow release-type nanoparticle cargo delivery devices, and enhanced the efficiency of AGnps for targeting cancer cells. AG nanoparticles also showed sufficient promise as safe anti-cancer drugs since they had minimal impact on animal hematology. Hence, we successfully prepared non-toxic and delivery-efficient andrographolide nanoparticles, and established for the first time that PLGA-nanoparticulation of andrographolide and additional chitosan coating increased its anti-cancer efficacy in human breast cancer cells and mouse EAC model.

Injuries to articular cartilage are one of the most challenging issues of musculoskeletal medicine due to the poor intrinsic ability of this tissue for repair. Despite progress in orthopaedic surgery, cell-based surgical therapies such as autologous chondrocyte transplantation (ACT) have been in clinical use for cartilage repair for over a decade but this approach has shown mixed results. Moreover, the lack of efficient modalities of treatment for large chondral defects has prompted research on cartilage tissue engineering combining cells, scaffold materials and environmental factors. This paper focuses on the main parameters in tissue engineering and in particular, on the potential of mesenchymal stem cells (MSCs) as an alternative to cells derived from patient tissues in autologous transplantation and tissue engineering. We discussed the prospects of using autologous chondrocytes or MSCs in regenerative medicine and summarized the advantages and disadvantages of these cells in articular cartilage engineering.

Prevention of hepatitis B, one of the most prevalent human diseases, still requires cheap and commonly available vaccines. Oral vaccines, including plant-based formulations, have been considered as alternatives or supplements for standard injection vaccines, due to the assumed low-cost production and simplified vaccination. Although plant production of HBV antigens is sufficiently efficient, despite almost 20 years of research still no anti-HBV plant-based vaccine has been developed. The basic difficulty has been to elaborate an effective immunisation procedure. Immunisation by parenteral priming and oral boosting with raw plant tissue adjuvanted with the cholera toxin, although effective, seemed to be unfeasible and controversial. Exclusively oral immunisation using lyophilised tissue, despite its appropriate form, appeared also impractical because of too low efficiency. Oral tolerance turned out to be the main barrier for anti-HBV plantbased vaccines. Based on previous results and knowledge on the mucosal immune system, a possible vaccine may consist of two components, parenteral for priming and oral for boosting. Probably the oral constituent could independently serve for further booster vaccinations. Both vaccine components can be produced in plants and used after some processing – purification for the injection constituent and lyophilisation for the oral one. Lyophilised tissue can be converted into tablets, capsules, etc. Previous and recent data show that the injection-oral immunisation regime may be efficient. A combination of parenteral and oral vaccination offers good prospects for a truly efficacious plant-derived anti-HBs vaccine and even a partial substitution of parenteral vaccines by an oral formula may prove to be economically reasonable.

Programmed cell death can occur through two separate pathways caused by treatment of Saccharomyces cerevisiae with acetic acid (AA-PCD), which differ from one another essentially with respect to their sensitivity to Nacetylcysteine (NAC) and to the role played by cytochrome c and metacaspase YCA1. Moreover, yeast can also undergo macroautophagy which occurs in NAC-insensitive manner. In order to gain some insight into the relationship between AA-PCD and macroautophagy use was made of WT and knock-out cells lacking YCA1 and/or cytochrome c. We show that i. macroautophagy is modulated by YCA1 and by cytochrome c in a negative and positive manner, respectively, ii. the NAC-insensitive AA-PCD and macroautophagy differ from one another and iii. NAC-insensitive AA-PCD pathway takes place essentially without macroautophagy, even if the shift of extracellular pH to acidic values required for AA-PCD to occur leads itself to increased or decreased macroautophagy in YCA1 or cytochrome c-lacking cells.

A number of transcriptional control elements are activated when Saccharomyces cerevisiae cells are submitted to various stress conditions, including high hydrostatic pressure (HHP). Exposure of Saccharomyces cerevisiae cells to HHP results in global transcriptional reprogramming, similar to that observed under other industrial stresses, such as temperature, ethanol and oxidative stresses. Moreover, treatment with a mild hydrostatic pressure renders yeast cells multistress tolerant. In order to identify transcriptional factors involved in coordinating response to high hydrostatic pressure, we performed a time series microarray expression analysis on a wild S. cerevisiae strain exposed to 50 MPa for 30 min followed by recovery at atmospheric pressure (0.1 MPa) for 5, 10 and 15 min. We identified transcription factors and corresponding DNA and RNA motifs targeted in response to hydrostatic pressure. Moreover, we observed that different motif elements are present in the promoters of induced or repressed genes during HHP treatment. Overall, as we have already published, mild HHP treatment to wild yeast cells provides multiple protection mechanisms, and this study suggests that the TFs and motifs identified as responding to HHP may be informative for a wide range of other biotechnological and industrial applications, such as fermentation, that may utilize HHP treatment.

Toona sinensis (Chinese Mahogany; Meliaceae), a subtropical deciduous tree, has a tangy scent resembling a mix of shallots and garlic. T. sinensis has long been known for its medicinal efficacy for treating enteritis, dysentery, itch and some cancers. However, its volatile components and their biosynthesis remain unexamined. In this study, we identified the spectrum of volatile compounds, isolated and functionally characterized two terpene synthase genes, Tstps1 and Tstps2, responsible for terpenoid synthesis in T. sinensis leaflets. TsTPS1 and TsTPS2 afford multiple products upon incubation with geranyl and farnesyl diphosphate respectively and mainly regulate the biosynthesis of (+) limonene and β- elemene in vitro, respectively. Headspace analyses show that 98% of leaflet volatiles were sesquiterpenoids and the developing leaflets released a greater diversity and quantity of volatiles than the mature leaflets did, and that β-elemene was the dominant component in both of them. These data suggested that tangy scent of T. sinensis consists of a combination of terpenoids and that Tstps2 was the major gene involved in the terpenoid biosynthesis in T. sinensis. In situ hybridization revealed that glandular cells of the leaf rachises accumulated abundant Tstps1 mRNA transcripts. Our GFP-based assay further unprecedentedly demonstrated that the transit-peptide of TsTPS1 targets specifically to the mitochondria.

Through the photosynthetic activity, microalgae process more than 25% of annual inorganic carbon dissolved in oceans into carbohydrates that ultimately, serve to feed the other levels of the trophic networks. Besides, microalgae synthesize bioactive molecules such as pigments and lipids that exhibit health properties. In addition, abiotic stresses, such as high irradiance, nutrient starvation, UV irradiation, trigger metabolic reorientations ending with the production of other bioactive compounds such as ω-3 fatty acids or carotenoids. Traditionally, these compounds are acquired through the dietary alimentation. The increasing, and often unsatisfied, demand for compounds from natural sources, combined with the decrease of the halieutic resources, forces the search for alternative resources for these bioactive components. Microalgae possess this strong potential. For instance, the diatom Odontella aurita is already commercialized as dietary complement and compete with fish oil for human nutrition. In this contribution, the microalga world is briefly presented. Then, the different types of biologically active molecules identified in microalgae are presented together with their potential use. Due to space limitation, only the biological activities of lipids and pigments are described in details. The contribution ends with a description of the possibilities to play with the environmental constrains to increase the productivity of biologically active molecules by microalgae and by a description of the progresses made in the field of alga culturing.

In order to valorize novel biotechnology innovations, there is a need to evaluate ex-ante their market potential. A case in point is biofortification, i.e. the enhancement of the micronutrient content of staple crops through conventional or genetic breeding techniques. In a recent article in Nature Biotechnology, for example, De Steur et al. (2010) demonstrated the large potential consumer health benefits of folate biofortified rice as a means to reduce folate deficiency and Neural-Tube Defects. By focusing on a Chinese high-risk region of Neural-Tube Defects, the current study defines the potential cost-effectiveness of this genetically modified crop where the need to improve folate intake levels is highest. Building on the Disability-Adjusted Life Years (DALY) approach, both the potential health impacts and costs of its implementation are measured and benchmarked against similar innovations. The results show that this transgenic crop could be a highly cost-effective product innovation (US$ 120.34 - US$ 40.1 per DALY saved) to alleviate the large health burden of folate deficiency and reduce the prevalence of neural-tube birth defects. When compared with other biofortified crops and target regions, folate biofortified rice in China has a relatively high health impact and moderate cost-effectiveness. This research further supports the need for, and importance of ex-ante evaluation studies in order to adequately market and, thus, valorize biotechnology innovations. Although the cost-effectiveness analysis enables to illustrate the market potential of innovative agricultural biotechnology research, further research is required to address policy issues on transgenic biofortification, such as biosafety regulatory requirements.

The progression of Alzheimer's disease (AD) is accompanied by disturbances of the endosome/lysosome (EL) system and there is accumulation of peptides of the AD-associated amyloid beta (Abeta) type in EL vesicles of affected neurons. EL modulating agents partially ameliorate the Abeta-mediated cell abnormalities. However, no extensive studies on the potential pharmaceutical applications of combinations of such agents and their synergistic effects have been performed. This study shows the beneficial anti-amyloid effects of several combinations of lysosomal modulators and other pharmacological and new nanobiotechnological agents. Some agents potentiated each other's action and some of them facilitated the anti-amyloid actions of memantine, a modifier of Ca2+-permeable channels involved in AD and one of the few drugs used for treatment of AD. Another compound used in nanobiotechnology ameliorated as a nanocarrier the beneficial effects of some of these potential pharmaceutical agents. They may be considered as additional drugs to improve the efficacy of the therapeutic approaches for AD and related neurodegenerative disorders.