There is a wide variety of cancer types yet, all share some common cellular and molecular behaviors. Most of the chemotherapeutic agents used in cancer treatment are designed to target common deregulated mechanisms within cancer cells. Many healthy tissues are also affected by the cytotoxic effects of these chemical agents. Fucoidan, a natural component of brown seaweed, has anti-cancer activity against various cancer types by targeting key apoptotic molecules. It also has beneficial effects as it can protect against toxicity associated with chemotherapeutic agents and radiation. Thus the synergistic effect of fucoidan with current anti-cancer agents is of considerable interest. This review discusses the mechanisms by which fucoidan retards tumor development, eradicates tumor cells and synergizes with anti-cancer chemotherapeutic agents. Challenges to the development of fucoidan as an anti-cancer agent will also be discussed.
Background Leucine‐rich repeat kinase 2 is a potential therapeutic target for the treatment of Parkinson's disease, and clinical trials of leucine‐rich repeat kinase 2 inhibitors are in development. The objective of this study was to evaluate phosphorylation of a new leucine‐rich repeat kinase 2 substrate, Rab10, for potential use as a target engagement biomarker and/or patient enrichment biomarker for leucine‐rich repeat kinase 2 inhibitor clinical trials. Methods Peripheral blood mononuclear cells and neutrophils were isolated from Parkinson's disease patients and matched controls, and treated ex vivo with a leucine‐rich repeat kinase 2 inhibitor. Immunoblotting was used to measure levels of leucine‐rich repeat kinase 2 and Rab10 and their phosphorylation. Plasma inflammatory cytokines were measured by multiplex enzyme‐linked immunosorbent assay. Results Mononuclear cells and neutrophils of both controls and Parkinson's disease patients responded the same to leucine‐rich repeat kinase 2 inhibitor treatment. Leucine‐rich repeat kinase 2 levels in mononuclear cells were the same in controls and Parkinson's disease patients, whereas leucine‐rich repeat kinase 2 was significantly increased in Parkinson's disease neutrophils. Rab10 T73 phosphorylation levels were similar in controls and Parkinson's disease patients and did not correlate with leucine‐rich repeat kinase 2 levels. Immune‐cell levels of leucine‐rich repeat kinase 2 and Rab10 T73 phosphorylation were associated with plasma inflammatory cytokine levels. Conclusions Rab10 T73 phosphorylation appears to be a valid target engagement biomarker for potential use in leucine‐rich repeat kinase 2 inhibitor clinical trials. However, a lack of association between leucine‐rich repeat kinase 2 and Rab10 phosphorylation complicates the potential use of Rab10 phosphorylation as a patient enrichment biomarker. Although replication is required, increased leucine‐rich repeat kinase 2 levels in neutrophils from Parkinson's disease patients may have the potential for patient stratification. leucine‐rich repeat kinase 2 activity in peripheral immune cells may contribute to an inflammatory phenotype. © 2018 International Parkinson and Movement Disorder Society
Missense mutations in glucocerebrosidase (GBA1) that impair the activity of the encoded lysosomal lipid metabolism enzyme (GCase) are linked to an increased risk of Parkinson’s disease. However, reduced GCase activity is also found in brain tissue from Parkinson’s disease patients without GBA1 mutations, implicating GCase dysfunction in the more common idiopathic form of Parkinson’s disease. GCase is very highly expressed in monocytes, and thus we measured GCase activity in blood samples from recently diagnosed Parkinson’s disease patients. Flow cytometry and immunoblotting assays were used to measure levels of GCase activity and protein in monocytes and lymphocytes from patients with Parkinson’s disease (n = 48) and matched controls (n = 44). Gene sequencing was performed to screen participants for GBA1 missense mutations. In the Parkinson’s disease patients, GCase activity was significantly reduced in monocytes, but not lymphocytes, compared to controls, even when GBA1 mutation carriers were excluded. Monocyte GCase activity correlated with plasma ceramide levels in the Parkinson’s disease patients. Our results add to evidence for GCase dysfunction in idiopathic Parkinson’s disease and warrant further work to determine if monocyte GCase activity associates with Parkinson’s disease progression.
Fucoidan, a natural component of seaweeds, is reported to have immunomodulatory and anti-tumor effects. The mechanisms underpinning these activities remain poorly understood. In this study, the cytotoxicity and anti-tumor activities of fucoidan were investigated in acute myeloid leukemia (AML) cells. The human AML cell lines NB4, KG1a, HL60, and K562 were treated with fucoidan and cell cycle, cell proliferation, and expression of apoptotic pathways molecules were analyzed. Fucoidan suppressed the proliferation and induced apoptosis through the intrinsic and extrinsic pathways in the acute promyelocytic leukemia (APL) cell lines NB4 and HL60, but not in KG1a and K562 cells. In NB4 cells, apoptosis was caspase-dependent as it was significantly attenuated by pre-treatment with a pan-caspase inhibitor. P21/WAF1/CIP1 was significantly up-regulated leading to cell cycle arrest. Fucoidan decreased the activation of ERK1/2 and down-regulated the activation of AKT through hypo-phosphorylation of Thr(308) residue but not Ser(473). In vivo, a xenograft model using the NB4 cells was employed. Mice were fed with fucoidan and tumor growth was measured following inoculation with NB4 cells. Subsequently, splenic natural killer (NK) cell cytotoxic activity was also examined. Oral doses of fucoidan significantly delayed tumor growth in the xenograft model and increased cytolytic activity of NK cells. Taken together, these data suggest that the selective inhibitory effect of fucoidan on APL cells and its protective effect against APL development in mice warrant further investigation of fucoidan as a useful agent in treatment of certain types of leukemia.
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