Fucoidans are natural sulfated polysaccharides that have a wide range of biological functions and are regarded as promising antitumor agents. The activity of various fucoidans and their derivatives has been demonstrated in vitro on tumor cells of different histogenesis and in experiments on mice with grafted tumors. However, these experimental models showed low levels of antitumor activity and clinical trials did not prove that this class of compounds could serve as antitumor drugs. Nevertheless, the anti-inflammatory, antiangiogenic, immunostimulating, and anticoagulant properties of fucoidans, as well as their ability to stimulate hematopoiesis during cytostatic-based antitumor therapy, suggest that effective fucoidan-based drugs could be designed for the supportive care and symptomatic therapy of cancer patients. The use of fucoidans in cancer patients after chemotherapy and radiation therapy might promote the rapid improvement of hematopoiesis, while their anti-inflammatory, immunomodulatory, and anticoagulant effects have the potential to improve the quality of life of patients with advanced cancer.

Crude anionic polysaccharides extracted from the Pacific starfish Lethasterias fusca were purified by anion-exchange chromatography. The main fraction LF, having MW 14.5 kDa and dispersity 1.28 (data of gel-permeation chromatography), was solvolytically desulfated and giving rise to preparation LF-deS with a structure of dermatan core [→3)-β-d-GalNAc-(1→4)-α-l-IdoA-(1→]_n, which was identified according to NMR spectroscopy data. Analysis of the NMR spectra of the parent fraction LF led to identification of the main component as dermatan sulfate LF-Derm →3)-β-d-GalNAc4R-(1→4)-α-l-IdoA2R3S-(1→ (where R was SO₃ or H), bearing sulfate groups at O-3 or both at O-2 and O-3 of α-l-iduronic acid, as well as at O-4 of some N-acetyl-d-galactosamine residues. The minor signals in NMR spectra of LF were assigned as resonances of heparinoid LF-Hep composed of the fragments →4)-α-d-GlcNS3S6S-(1→4)-α-l-IdoA2S3S-(1→. The 3-O-sulfated and 2,3-di-O-sulfated iduronic acid residues are very unusual for natural glycosaminoglycans, and further studies are needed to elucidate their possible specific influence on the biological activity of the corresponding polysaccharides. To confirm the presence of these units in LF-Derm and LF-Hep, a series of variously sulfated model 3-aminopropyl iduronosides were synthesized and their NMR spectra were compared with those of the polysaccharides. Preparations LF and LF-deS were studied as stimulators of hematopoiesis in vitro. Surprisingly, it was found that both preparations were active in these tests, and hence, the high level of sulfation is not necessary for hematopoiesis stimulation in this particular case.

Introduction. Ex vivo expansion of natural killer (NK) and natural killer T-cells (NKT) cells is an important element in the generation of chimeric antigen receptor NK and NKT cells. Monoclonal antibodies (mAbs) to CD (cluster of differentiation) 3 and CD28 receptors are most often used for lymphocyte expansion. Other well-studied T-cell mitogens include phytohaemagglutinin-L (L-PHA) and concanavalin A (ConA). A promising but poorly studied approach is in vitro activation of immune cells with the polysaccharide fucosylated chondroitin sulfate (FCS) isolated from the sea cucumber Cucumaria japonica, which is able to activate immune cells and stimulate hematopoiesis. Aim. To identify the optimal method for NK and NKT cell activation in primary lymphocyte culture. For this purpose, we tested mAbs to CD3 and CD28 receptors, L-PHA, ConA, and a combination of mAbs to CD3 and CD28 receptors and FCS. Materials and methods. Peripheral blood and leukocyte-platelet concentrate were used as a source of peripheral blood mononuclear cells (PBMC). After isolation of PBMC, they were activated using adsorbed mAbs to CD3 and CD28 receptors, L-PHA, ConA, or a mAbs + FCS combination. Then, lymphocytes were cultured in the presence of IL-2, periodically assessing the increase in the total number of cells, expression of surface markers, and cytotoxic activity. Results. It was shown that L-PHA best stimulated the expansion of T lymphocytes (CD3+CD56–) and NK cells (CD3–CD56+) relative to other activation modes. Under the influence of ConA, the division of CD3+CD4+ lymphocytes was significantly activated. When comparing the activation of cells under the influence of MAT relative to L-PHA and ConA, the most pronounced increase in the CD3+CD56+ population was observed. The addition of FCS during MAT stimulation led to an increase in lymphocyte proliferation. Conclusion. Thus, among the presented methods of PBMC activation for stimulating the expansion of NK and NKT cells, the most preferable was the MAT + FCS activation method, since it resulted in the greatest increase in the total number of cells with a maximum proportion of CD56+ lymphocytes, amounting to 58.9% by the end of the culturing period.

D-Glucuronic acid is a fundamental building block of many biologically important polysaccharides, either in its non-substituted form or bearing a variety of substituents, among them sulfates. We have previously performed a study of the effects of exhaustive sulfation on the conformational behavior of β-gluronopyranosides. Herein, we report an investigation comparing α- and β-derivatives of this monosaccharide within the title disaccharides using NMR and quantum chemistry approaches. It was found that for α-linked disaccharides, the introduction of sulfates did not greatly affect their conformational behavior. However, for β-derivatives, considerable conformational changes were observed. In general, they resemble those that took place for the monosaccharides, except that NOESY experiments and calculations of intra-ring spin–spin coupling constants suggest the presence of a 1S5 conformer along with 3S1 in the fully sulfated disaccharide. During the synthesis of model compounds, hydrogen bond-mediated aglycone delivery was used as an α-directing stereocontrol approach in the glucuronidation reaction.