Assessing Polysaccharides/Aloe Vera-Based Hydrogels for Tumor Spheroid Formation.

In vitro tumor spheroids have proven to be useful 3D tumor culture models for drug testing, and determining the molecular mechanism of tumor progression and cellular interactions. Therefore, there is a continuous search for their industrial scalability and routine preparation. Considering that hydrogels are promising systems that can favor the formation of tumor spheroids, our study aimed to investigate and develop less expensive and easy-to-use amorphous and crosslinked hydrogels, based on natural compounds such as sodium alginate (NaAlg), aloe vera (AV) gel powder, and chitosan (CS) for tumor spheroid formation. The ability of the developed hydrogels to be a potential spheroid-forming system was evaluated using MDA-MB-231 and U87MG cancer cells. Spheroid abilities were influenced by pH, viscosity, and crosslinking of the hydrogel. Addition of either AV or chitosan to sodium alginate increased the viscosity at pH 5, resulting in amorphous hydrogels with a strong gel texture, as shown by rheologic analysis. Only the chitosan-based gel allowed formation of spheroids at pH 5. Among the variants of AV-based amorphous hydrogels tested, only hydrogels at pH 12 and with low viscosity promoted the formation of spheroids. The crosslinked NaAlg/AV, NaAlg/AV/glucose, and NaAlg/CS hydrogel variants favored more efficient spheroid formation. Additional studies would be needed to use AV in other physical forms and other formulations of hydrogels, as the current study is an initiation, in evaluating the potential use of AV gel in tumor spheroid formation systems.

Fatty Acids, CD36, Thrombospondin-1, and CD47 in Glioblastoma: Together and/or Separately?

Glioblastoma (GBM) is one of the most aggressive tumors of the central nervous system, characterized by a wide range of inter- and intratumor heterogeneity. Accumulation of fatty acids (FA) metabolites was associated with a low survival rate in high-grade glioma patients. The diversity of brain lipids, especially polyunsaturated fatty acids (PUFAs), is greater than in all other organs and several classes of proteins, such as FA transport proteins (FATPs), and FA translocases are considered principal candidates for PUFAs transport through BBB and delivery of PUFAs to brain cells. Among these, the CD36 FA translocase promotes long-chain FA uptake as well as oxidated lipoproteins. Moreover, CD36 binds and recognizes thrombospondin-1 (TSP-1), an extracellular matrix protein that was shown to play a multifaceted role in cancer as part of the tumor microenvironment. Effects on tumor cells are mediated by TSP-1 through the interaction with CD36 as well as CD47, a member of the immunoglobulin superfamily. TSP-1/CD47 interactions have an important role in the modulation of glioma cell invasion and angiogenesis in GBM. Separately, FA, the two membrane receptors CD36, CD47, and their joint ligand TSP-1 all play a part in GBM pathogenesis. The last research has put in light their interconnection/interrelationship in order to exert a cumulative effect in the modulation of the GBM molecular network.

A Fatty Acid Fraction Purified From Sea Buckthorn Seed Oil Has Regenerative Properties on Normal Skin Cells.

In recent years, natural product's research gained momentum, fueled by technological advancement and open availability of research data. To date, sea buckthorn (Hippophae rhamnoides L. [Elaeagnaceae]) plant parts, especially berries, are well characterized and repeatedly tested for antioxidant activity and regenerative properties, in various cell types and tissues. However, fatty acids (FA) have been less investigated in term of biological effects, although, they are important bioactive components of the sea buckthorn fruit and oil. The aim of our work was to determine whether sea buckthorn seed oil is a suitable source of FA with regenerative properties on normal skin cells. Using high-performance liquid chromatography (HPLC) and liquid chromatography - mass spectrometry (LC-MS), we purified and characterized four fractions enriched in saturated (palmitic) and non-saturated (linoleic, alfa-linolenic, oleic) FA, which were tested for cytotoxicity, cytokine and growth factor production, and regenerative effect on normal keratinocytes and skin fibroblasts. Evidence is presented that the palmitic acid enriched fraction was a suitable sea buckthorn seed oil derived product with cell proliferation properties on both skin cell types.

Traumatic Intralenticular Neovascularization in a HLA B27+ Pediatric Patient.

(1) Background: Intralenticular tumors are an entity akin to Schrodinger's cat since, although the human crystalline cells themselves are not known to malignly proliferate, various entities can take the appearance and clinical presentation of a tumor originating in the lens. We present the peculiar case of an 11-year-old male patient of African descent, HLA B27+, with a previous history of minor ocular trauma and unilateral anterior uveitis a year before which was admitted to our department with total opacification of the crystalline lens in the right eye and lens neovascularization. During surgery, a vascular, white fibrotic mass measuring 0.1-0.2 cm was discovered inside the lens bag and was excised. (2) Methods: Retrospective case review. (3) Results: The histopathological exam of the excised mass revealed an abundant infiltrate consisting of CD68+ foamy macrophages and lymphoplasmacytic elements. CD68 is a pan-macrophage marker associated with an active inflammatory mechanism soliciting macrophages, and tissue activated macrophages are correlated to increased stromal and serum levels of vascular endothelial growth factor, providing an explanation for lens angiogenesis. (4) Conclusions: The diagnosis is of a "masquerade tumor" resulted from an abnormal inflammatory process in connection with previous ocular trauma and possibly the patient's HLA B27+ status.

Two Worlds Colliding: The Interplay Between Natural Compounds and Non-Coding Transcripts in Cancer Therapy.

Cancer is a devastating disease and has recently become the leading cause of death in western countries, representing an immense public health burden. When it comes to cancer treatment, chemotherapy is one of the main pillars, especially for advanced stage tumors. Over the years, natural compounds have emerged as one of the most valuable resources for new chemotherapies. It is estimated that more than half of the currently used chemotherapeutic agents are derived from natural compounds. Usually, natural compounds are discovered empirically and an important limitation of introducing new anti-cancer natural products is lack of knowledge with regard to their mechanism of action. Recent data has proven that several natural compounds may function via modulating the expression and function of non-coding RNAs (ncRNAs). NcRNAs are a heterogenous class of RNA molecules which are usually not translated into proteins but have an important role in gene expression regulation and are involved in multiple tumorigenic processes, including response/resistance to pharmacotherapy. In this review, we will discuss how natural compounds function via ncRNAs while summarizing the available data regarding their effects on over 15 types of cancer. Moreover, we will critically analyze the current advances and limitations in understanding the way natural compounds exert these health-promoting effects by acting on ncRNAs. Finally, we will propose several hypotheses that may open new avenues and perspectives regarding the interaction between natural compounds and ncRNAs, which could lead to improved natural compound-based therapeutic strategies in cancer.

The Physico-Chemical Properties and Exploratory Real-Time Cell Analysis of Hydroxyapatite Nanopowders Substituted with Ce, Mg, Sr, and Zn (0.5-5 at.%).

Cation-substituted hydroxyapatite (HA), standalone or as a composite (blended with polymers or metals), is currently regarded as a noteworthy candidate material for bone repair/regeneration either in the form of powders, porous scaffolds or coatings for endo-osseous dental and orthopaedic implants. As a response to the numerous contradictions reported in literature, this work presents, in one study, the physico-chemical properties and the cytocompatibility response of single cation-doped (Ce, Mg, Sr or Zn) HA nanopowders in a wide concentration range (0.5-5 at.%). The modification of composition, morphology, and structure was multiparametrically monitored via energy dispersive X-ray, X-ray photoelectron, Fourier-transform infrared and micro-Raman spectroscopy methods, as well as by transmission electron microscopy and X-ray diffraction. From a compositional point of view, Ce and Sr were well-incorporated in HA, while slight and pronounced deviations were observed for Mg and Zn, respectively. The change of the lattice parameters, crystallite size, and substituting cation occupation factors either in the Ca(I) or Ca(II) sites were further determined. Sr produced the most important HA structural changes. The in vitro biological performance was evaluated by the (i) determination of leached therapeutic cations (by inductively coupled plasma mass spectrometry) and (ii) assessment of cell behaviour by both conventional assays (e.g., proliferation-3-(4,5-dimethyl thiazol-2-yl) 5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay; cytotoxicity-lactate dehydrogenase release assay) and, for the first time, real-time cell analysis (RTCA). Three cell lines were employed: fibroblast, osteoblast, and endothelial. When monophasic, the substituted HA supported the cells' viability and proliferation without signs of toxicity. The RTCA results indicate the excellent adherence of cells. The study strived to offer a perspective on the behaviour of Ce-, Mg-, Sr-, or Zn-substituted HAs and to deliver a well-encompassing viewpoint on their effects. This can be highly important for the future development of such bioceramics, paving the road toward the identification of candidates with highly promising therapeutic effects.

Sea-Buckthorn Seed Oil Induces Proliferation of both Normal and Dysplastic Keratinocytes in Basal Conditions and under UVA Irradiation.

Past decades demonstrate an increasing interest in herbal remedies in the public eye, with as many as 80% of people worldwide using these remedies as healthcare products, including those for skin health. Sea buckthorn and its derived products (oil; alcoholic extracts), rich in flavonoids and essential fatty acids, are among these healthcare products. Specifically, sea buckthorn and its derivatives are reported to have antioxidant and antitumor activity in dysplastic skin cells. On the other hand, evidence suggests that the alteration of lipid metabolism is related to increased malignant behavior. Given the paradoxical involvement of lipids in health and disease, we investigated how sea-buckthorn seed oil, rich in long-chain fatty acids, modifies the proliferation of normal and dysplastic skin cells in basal conditions, as well as under ultraviolet A (UVA) radiation. Using real-time analysis of normal and dysplastic human keratinocytes, we showed that sea-buckthorn seed oil stimulated the proliferation of dysplastic cells, while it also impaired the ability of both normal and dysplastic cells to migrate over a denuded area. Furthermore, UVA exposure increased the expression of CD36/SR-B2, a long-chain fatty acid translocator that is related to the metastatic behavior of tumor cells.

CD36 in Alzheimer's Disease: An Overview of Molecular Mechanisms and Therapeutic Targeting.

CD36 is a membrane protein with wide distribution in the human body, is enriched in the monocyte-macrophage system and endothelial cells, and is involved in the cellular uptake of long chain fatty acids (LCFA) and oxidized low-density lipoproteins. It is also a scavenger receptor, binding hydrophobic amyloid fibrils found in the Alzheimer's disease (AD) brain. In neurobiology research, it has been mostly studied in relationship with chronic ischemia and stroke, but it was also related to amyloid clearance by microglial phagocytosis. In AD animal models, amyloid binding to CD36 has been consistently correlated with a pro-inflammatory response. Therapeutic approaches have two main focuses: CD36 blockade with monoclonal antibodies or small molecules, which is beneficial in terms of the inflammatory milieu, and upregulation of CD36 for increased amyloid clearance. The balance of the two approaches, centered on microglia, is poorly understood. Furthermore, CD36 evaluation in AD clinical studies is still at a very early stage and there is a gap in the knowledge regarding the impact of LCFA on AD progression and CD36 expression and genetic phenotype. This review summarizes the role played by CD36 in the pathogenic amyloid cascade and explore the translatability of preclinical data towards clinical research.

Caveolae as Potential Hijackable Gates in Cell Communication.

Caveolae are membrane microdomains described in many cell types involved in endocytocis, transcytosis, cell signaling, mechanotransduction, and aging. They are found at the interface with the extracellular environment and are structured by caveolin and cavin proteins. Caveolae and caveolins mediate transduction of chemical messages via signaling pathways, as well as non-chemical messages, such as stretching or shear stress. Various pathogens or signals can hijack these gates, leading to infectious, oncogenic and even caveolin-related diseases named caveolinopathies. By contrast, preclinical and clinical research have fallen behind in their attempts to hijack caveolae and caveolins for therapeutic purposes. Caveolae involvement in human disease is not yet fully explored or understood and, of all their scaffold proteins, only caveolin-1 is being considered in clinical trials as a possible biomarker of disease. This review briefly summarizes current knowledge about caveolae cell signaling and raises the hypothesis whether these microdomains could serve as hijackable "gatekeepers" or "gateways" in cell communication. Furthermore, because cell signaling is one of the most dynamic domains in translating data from basic to clinical research, we pay special attention to translation of caveolae, caveolin, and cavin research into clinical practice.

Comprehensive In Vitro Testing of Calcium Phosphate-Based Bioceramics with Orthopedic and Dentistry Applications.

Recently, a large spectrum of biomaterials emerged, with emphasis on various pure, blended, or doped calcium phosphates (CaPs). Although basic cytocompatibility testing protocols are referred by International Organization for Standardization (ISO) 10993 (parts 1-22), rigorous in vitro testing using cutting-edge technologies should be carried out in order to fully understand the behavior of various biomaterials (whether in bulk or low-dimensional object form) and to better gauge their outcome when implanted. In this review, current molecular techniques are assessed for the in-depth characterization of angiogenic potential, osteogenic capability, and the modulation of oxidative stress and inflammation properties of CaPs and their cation- and/or anion-substituted derivatives. Using such techniques, mechanisms of action of these compounds can be deciphered, highlighting the signaling pathway activation, cross-talk, and modulation by microRNA expression, which in turn can safely pave the road toward a better filtering of the truly functional, application-ready innovative therapeutic bioceramic-based solutions.

Could caveolae be acting as warnings of mitochondrial ageing?

Ageing is a cellular process with many facets, some of which are currently undergoing a paradigm change. It is the case of "mitochondrial theory of ageing", which, interestingly, has been found lately to cross paths with another ageing dysfunctional process - intracellular signalling - in an unexpected point (or place) - caveolae. The latter represent membrane microdomains altered in senescent cells, scaffolded by proteins modified (posttranslational or as expression) with ageing. An important determinant of these alterations is oxidative stress, through increased production of reactive oxygen species that originate at mitochondrial site. Spanning from physical contact points, to shared structural proteins and similar function domains, caveolae and mitochondria might have more in common than originally thought. By reviewing recent data on oxidative stress impact on caveolae and caveolins, as well as possible interactions between caveolae and mitochondria, we propose a hypothesis for senescence-related involvement of caveolins.