Towards the Clinical Use of Phytoplankton Carotenoid Pigments to Cure Cancer

International audienceBeyond their major ecolophysiological functions, phytoplankton pigments exert biological and pharmacological activities in human cells that allow considering their clinical use to cure various pathologies. Although much of our knowledge relating to their cell pharmacology and bioactivity has come from in vitro studies in cell culture models, recent in vivo studies have validated the potential of phytoplankton carotenoid pigments to limit inflammation and metabolic disorders, retinal diseases, degenerative diseases, tumor progression, and hepatotoxicity. Aside from these promising results, additional studies are now required to precise their pharmacokinetics, pharmacological targets, and clinical efficacy in humans. The availability of highly purified pigments at rational costs will be a milestone to set up clinical trials and develop new therapies using microalgae pigments. This short paper focuses on the great potential of phytoplankton carotenoid pigments to prevent and cure cancers. Marine and freshwater microalgae have evolved a wide range of pigments that belong to the chlorophylls, carotenoids and phycobiliproteins families. Extensive research has proved that microalgae pigments exert significant biological and pharmacological activities in human cells. Beyond their well-known antioxidant activity, used as a commercial argument to sell algae-based cosmetics and nutraceutics, it is now clearly established that microalgae pigments have a great potential as health nutrients to prevent cancer, as biotechnological probes for cancer diagnosis and as anticancer drugs to trigger cancer cells apoptosis, prevent tumor angiogenesis, reduce the risk of metastasis, sensitize cancer cells to chemotherapy, destroy cancer cells by tumor phototherapy and filter UV to limit cancer cells initiation. Numerous studies aiming to identify antiproliferative molecules from microalgae extracts led to the isolation of carotenoids and to the demonstration of their high antiproliferative, cytostatic, cytotoxic, and/or pro-apoptotic activity in cancer cell cultures [1,2]. As an example, our research team performed the bioguided isolation of pigments from Duniella tertiolecta and found that violaxanthin was the most antiproliferative molecule contained in Dt dichloromethane extract [3]. We also recently reported the strong antiproliferative activity of zeaxanthin and β-cryptoxanthin in human invasive melanoma cells, after their bioguided isolation from Cyanophora paradoxa ethanolic extracts [4]

Clarification of Most Relevant Concepts Related to the Microalgae Production Sector

Microalgae (including cyanobacteria) are the basis for an emerging worldwide industry but still face significant bottlenecks in contributing to the global economy. It is an enormous challenge to translate experiences from established industries such as aquaculture and agriculture to the microalgae sector. In particular, this includes the challenge of adapting regulations that apply to such macroscopic production and mindsets, to the microscopic world of microalgae and to the scale-up to a million times smaller. Current European and country-based regulations do not always, indeed rarely, consider relevant specific issues that limit the path for innovation and growth applicable to the microalgae sector. In this work, the boundaries for the main issues impacting this sector are presented and discussed. Examples and possible analytical frameworks are presented in a question and answer format. Relevant key topics and related boundaries are discussed: What are algae and how do microalgae differ from macroalgae? Why are algae and specifically microalgae relevant? Is algae cultivation an aquaculture process? Can algae and specifically microalgae be classified as vegetables and their production be classified as agriculture or are they an industrial process? How is algaculture compared with other agricultural sectors? What are organic algae? Can microalgae be grown in wastewater and how can they be used? What are toxic algae? What are the bottlenecks for microalgae culture scale-up? How does the microalgae biodiversity contribute to their development? We conclude that microalgae are developing as a novel agricultural enterprise that can provide major benefits to a sustainable circular economy and environment but require appropriate regulations and support from governments and businesses, recognising its unique attributes and potential

Digital expression profiling of novel diatom transcripts provides insight into their biological functions

Background: Diatoms represent the predominant group of eukaryotic phytoplankton in the oceans and are responsible for around 20% of global photosynthesis. Two whole genome sequences are now available. Notwithstanding, our knowledge of diatom biology remains limited because only around half of their genes can be ascribed a function based onhomology-based methods. High throughput tools are needed, therefore, to associate functions with diatom-specific genes. Results: We have performed a systematic analysis of 130,000 ESTs derived from Phaeodactylum tricornutum cells grown in 16 different conditions. These include different sources of nitrogen, different concentrations of carbon dioxide, silicate and iron, and abiotic stresses such as low temperature and low salinity. Based on unbiased statistical methods, we have catalogued transcripts with similar expression profiles and identified transcripts differentially expressed in response to specific treatments. Functional annotation of these transcripts provides insights into expression patterns of genes involved in various metabolic and regulatory pathways and into the roles of novel genes with unknown functions. Specific growth conditions could be associated with enhanced gene diversity, known gene product functions, and over-representation of novel transcripts. Comparative analysis of data from the other sequenced diatom, Thalassiosira pseudonana, helped identify several unique diatom genes that are specifically regulated under particular conditions, thus facilitating studies of gene function, genome annotation and the molecular basis of species diversity. Conclusions: The digital gene expression database represents a new resource for identifying candidate diatom-specific genes involved in processes of major ecological relevance

Hepatic Stem-like Phenotype and Interplay of Wnt/β-Catenin and Myc Signaling in Aggressive Childhood Liver Cancer

SummaryHepatoblastoma, the most common pediatric liver cancer, is tightly linked to excessive Wnt/β-catenin signaling. Here, we used microarray analysis to identify two tumor subclasses resembling distinct phases of liver development and a discriminating 16-gene signature. β-catenin activated different transcriptional programs in the two tumor types, with distinctive expression of hepatic stem/progenitor markers in immature tumors. This highly proliferating subclass was typified by gains of chromosomes 8q and 2p and upregulated Myc signaling. Myc-induced hepatoblastoma-like tumors in mice strikingly resembled the human immature subtype, and Myc downregulation in hepatoblastoma cells impaired tumorigenesis in vivo. Remarkably, the 16-gene signature discriminated invasive and metastatic hepatoblastomas and predicted prognosis with high accuracy

Mise au point de méthodes de manipulation embryonnaire de mollusques bivalves. Application en génétique et pathologie infectieuse

Après vingt ans de programmes pivilégiant les méthodes d'élevage, les recherches concernant l'aquaculture, évoluent maintenant vers les domaines de la pathologie infectieuse et la génétique. La maîtrise des productions larvaires a en effet favorisé l'étude de la reproduction et de l'embryologie, et permet désormais d'aborder des travaux expérimentaux sur les différents stades embryonnaires. La polyploïdisation d'oeufs de moules ou d'huîtres a d'abord été envisagée par l'application d'un procédé d'électrofusion. Des expérimentations à grande échelle ont permis l'obtention d'embryons triploïdes (55% chez les huîtres et 36% chez les moules) ainsi que tétraploïdes (20% chez les huîtres et 26% chez les moules). La microinjection de spermatozoïdes a permis de tester la survie des ovocytes à l'introduction de ces larges particules. La transformation des gamètes mâles injectés en pronucléi a confirmé la faisabilité de la technique. Cette dernière a ensuite été employée à l'injection de Rickettsies dans des jeunes trochophores. La survie des mollusques ainsi injectés et la détection ultérieure intra-embrionnaire de l'agent pathogène pourrait ouvrir la voie de l'embryoculture. Enfin la microinjection d'ADN exogène (Lac-z) et la détection chez les embryons de moules ou d'huîtres du produit d'expression (B-galactosidase) de ce gène injecté, jette les bases d'une stratégie d'obtention d'animaux transgéniques. En conclusion, ces méthodes sont discutées et considérées dans le cadre d'une prochaine disponibilité d'animaux possédant des capacitiés de dérenses accrues vis-à-vis de leurs pathogènes

La production de biocarburant lipidique avec des microalgues : promesses et défis

Les microalgues peuvent accumuler des acides gras jusqu'à 80 % de leur poids sec (Chisti 2007) permettant d'envisager des rendements à l'hectare supérieurs d'un facteur 30 aux espèces oléagineuses terrestres. La biodiversité des microalgues est énorme puisqu'on estime qu'il y a entre 200 000 et plusieurs millions d'espèces. Une telle diversité non exploitée constitue un réel potentiel pour la recherche et l'industrie. Comparativement aux espèces oléagineuses terrestres, ces microalgues répondent à de nombreux problèmes environnementaux, avec des rendements de croissance et par conséquent des productions d'huile à l'hectare supérieurs aux espèces oléagineuses terrestres. Les microalgues suscitent actuellement un vif engouement et de nombreuses start-ups investissent ce créneau. Néanmoins, il reste encore des verrous à lever, via des recherches amont, avant que les rendements et les coûts espérés soient effectivement atteints et que ces technologies puissent voir le jour à grande échelle

Les promesses des microalgues pour la production de biodiesel

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7. Biomasse aquatique, micro-algues

Biomasse microalgale Les micro-algues (en incluant les cyanobactéries*) sont des êtres unicellulaires utilisant l’énergie de la lumière pour se développer. Avec seulement quelques dizaines d’espèces de micro-algues cultivées (pour quelques centaines de milliers dans le milieu naturel), la production mondiale annuelle est de l’ordre de 10 000 tonnes. Les espèces les plus cultivées sont par ordre décroissant : Arthrospira (la spiruline), qui représenterait 50 % de la production mondiale, suivie..