Haloarchaea: A Promising Biosource for Carotenoid Production.

Haloarchaea are halophilic microorganisms belonging to the Archaea domain that inhabit salty environments (mainly soils and water) all around the world. Most of the genera included in this group are able to produce carotenoids at significant concentrations (even wild-type strains). The major carotenoid produced by the cells is bacterioruberin (and its derivatives), which is only produced by this kind of microbes. Nevertheless, the understanding of carotenoid metabolism in haloarchaea, its regulation, and the roles of carotenoid derivatives in this group of extreme microorganisms remains mostly unrevealed. Besides, potential biotechnological uses of haloarchaeal pigments are poorly explored. This work summarizes what it has been described so far about carotenoid production by haloarchaea, haloarchaeal carotenoid production at large scale, as well as the potential uses of haloarchaeal pigments in biotechnology and biomedicine.

Carotenoids from Haloarchaea and Their Potential in Biotechnology.

The production of pigments by halophilic archaea has been analysed during the last half a century. The main reasons that sustains this research are: (i) many haloarchaeal species possess high carotenoids production availability; (ii) downstream processes related to carotenoid isolation from haloarchaea is relatively quick, easy and cheap; (iii) carotenoids production by haloarchaea can be improved by genetic modification or even by modifying several cultivation aspects such as nutrition, growth pH, temperature, etc.; (iv) carotenoids are needed to support plant and animal life and human well-being; and (v) carotenoids are compounds highly demanded by pharmaceutical, cosmetic and food markets. Several studies about carotenoid production by haloarchaea have been reported so far, most of them focused on pigments isolation or carotenoids production under different culture conditions. However, the understanding of carotenoid metabolism, regulation, and roles of carotenoid derivatives in this group of extreme microorganisms remains mostly unrevealed. The uses of those haloarchaeal pigments have also been poorly explored. This work summarises what has been described so far about carotenoids production by haloarchaea and their potential uses in biotechnology and biomedicine. In particular, new scientific evidence of improved carotenoid production by one of the better known haloarchaeon (Haloferax mediterranei) is also discussed.

CD44 induces FOXP3 expression and is related with favorable outcome in breast carcinoma.

We studied the relationship between CD44 and Forkhead box P3 (FOXP3) gene expression in cell lines and breast carcinomas and their association with clinicopathological variables and patient outcome. We assessed messenger RNA (mRNA) expression of CD44 and FOXP3 by quantitative real-time PCR and determined the number of FOXP3+ Tregs by immunohistochemistry in 264 breast cancer specimens. CD44 was stimulated with hyaluronan treatment, and the accompanying changes in FOXP3 mRNA expression in breast cancer cell lines representing breast cancer subtype were assessed. We found that lower CD44 expression correlated with the presence of necrosis, lymph-vascular invasion, grade 3 tumors, and aggressive phenotype (HER2 and basal-like). FOXP3 mRNA correlated positively with CD44 mRNA expression and Treg content. Moreover, stimulation of CD44 expression by hyaluronan in cell lines increased FOXP3 expression, which supports that their regulation is associated. Survival analysis revealed that low CD44 expression is associated with higher frequency of recurrence. Our findings indicate that CD44 has a regulatory role in FOXP3 expression and is associated with good prognostic factors in breast cancer.