Biology subjects

Assef, A. N. B.

Publications and source records attributed to Assef, A. N. B..

3 recordsLinked to original sources

bioRxiv2023

SULFATED POLYSACCHARIDE FROM BROWN ALGAE DICTYOTA CARIBAEA STIMULATES MACROPHAGES TO AN ANTITUMORAL PHENOTYPE

Fucoidans are sulfated polysaccharides capable of exerting biological activities such as antitumor and immunomodulatory effects. Previous studies demonstrated the antitumor activity of non-cytotoxic fucoidan from the seaweed Dictyota caribaea (Dc-SP) in vivo. Macrophages (M{varphi}) are innate immune cells capable of promoting or inhibiting tumor growth depending on the stimulus. This study aimed to evaluate the immunostimulant activity of Dc-SP on murine M{varphi} (RAW264.7) in vitro. Dc-SP was assessed for its ability to modify cell viability and stimulate the production of antitumor markers on RAW264.7 cells. Dc-SP induced an increase (p<0.05) in the production of NO and cytokines TNF-, IL-1{beta}, and IL-10. The exposure of M{varphi} to Dc-SP also increased (p<0.05) the expression of M1 macrophage markers such as iNOS, CD86, and MHC II. The antiproliferative activity of RAW264.7 cells stimulated with DC-SP on melanoma cells (B16-F10) in vitro. Dc-SP did not exhibit direct cytotoxicity on B16-F10, however, the conditioned medium (CM) of RAW264.7 previously stimulated with Dc-SP (CM-Dc-SP) showed antiproliferative activity on tumor cells. B16-F10 incubated with CM-Dc-SP showed a cytostatic profile, tumor cells did not alter membrane integrity, however, suffered morphological changes such as cell shrinkage and high granularity. In conclusion, Dc-SP stimulated M{varphi} to an antitumor phenotype.

immunology↗

bioRxiv2021

Sulfated polysaccharides from red seaweed Gracilaria cornea induce macrophages polarization to an antitumor M1 phenotype

Marine seaweeds are a rich source of sulfated polysaccharides with several biological activities, including antitumor effect. Some polysaccharides are also described to activate macrophages (M{phi}s) to an antitumor M1-like phenotype. Here, we evaluated the capacity of sulfated galactans (SGs) extracts obtained from three seaweed species, Gracilaria cornea (Gc-E), Gracilaria birdiae (Gb-E), and Solieria filiformis (Sf-E), to activate the M{phi}s antitumor M1 phenotype. The nitric oxide production, MHCII, and CD86 (M1 markers) were evaluated to screening the bioactive SGs profile on murine M{phi}s (RAW 264.7 cells). The direct SGs antiproliferative effect was tested on melanoma B16-F10 cells. In another experimental setting, B16-F10 cells were incubated with a conditioned medium obtained from M{phi}s exposed to SGs. The three SGs tested induced NO release. Sf-E directly inhibited B16-F10 cells proliferation compared with the saline group, but Gc-E and Gb-E failed to inhibit cell proliferation. Notably, a conditioned medium (CM) of M{phi}s incubated with Gc-E and Sf-E, but not of Gb-E, inhibited the proliferation of B16-F10 cells. Gc-E also induced TNF- release and increase of M1 markers such as iNOS, MHCII, and CD86. Therefore, Gc-E activates M{phi}s to M1 phenotype, which in turn releases a factor that inhibits B16-F10 proliferation.

pharmacology and toxicology↗

bioRxiv2020

ANTITUMOR SULFATED POLYSACCHARIDES FROM BROWN ALGAE Dictyota caribaea

Sulfated polysaccharides (SP) are a complex group of bioactive molecules able to inhibit tumor growth. SP increase the effectiveness of chemotherapy and reduce some side effects. Brown algae produce SP with several biological activities including antitumor. This work aimed to investigate the antitumor effect of SP from the brown algae Dictyota caribaea (Dc-SP). Dc-SP were extracted with proteolytic enzyme and supernatant was precipitated with increasing concentrations of ethanol. Antiproliferative activity of Dc-SP was tested by the MTT assay against colon cancer (HCT 116) and metastatic melanoma (B16-F10) cell lines. The antitumor effect was evaluated on Swiss mice transplanted with sarcoma 180 tumor and treated i.p. during 7 days with saline or Dc-SP (25 and 50 mg/kg/animal). Dc-SP did not exhibit cytotoxicity in vitro, however the Dc-SP-treated mice depicted up to 50% tumor growth inhibition. Dc-SP treatment induced spleen weight increasing along with intense white pulp disorganization. Furthermore Dc-SP did not depict hepatic toxicity, nephrotoxicity nor leukopenia and did induce increase of platelets count. Altogether, these results represent a promising antitumor host dependent effect induced by Dc-SP.

pharmacology and toxicology↗