A novel cell-wall polysaccharide derived from the stipe of Agaricus bisporus inhibits mouse melanoma proliferation and metastasis.

Malignant melanoma is an invasive and highly aggressive skin cancer that-if diagnosed-poses a serious threat to the patient's health and life. In this work, a novel purified cell-wall polysaccharide (termed Abwp) was obtained from the discarded stipe of Agaricus bisporus (A. bisporus) and characterized to be a novel homogeneous polysaccharide consisted of a ß-(1 â†’ 4)- glucosyl backbone with ß-(1 â†’ 2) and (1 â†’ 6)-d-glucosyl side-chains. The anti-melanoma effects of Abwp and its associated mechanisms in mice were then explored using in vitro and in vivo approaches. In vitro results showed that Abwp inhibited B16 melanoma cell proliferation and promoted their apoptosis in both time- and dose-dependent manners. In B16 cells induced with tumor necrosis factor (TNF-α), Abwp significantly decreased the protein expression of inflammatory-related signaling pathway (e.g., p38 MAPK and NF-κB) in time-, concentration-, and dose-dependent manners. Moreover, Abwp blocked nuclear entry of NF-κB-p65. In an in vivo mouse model featuring neoplasm transplantation with B16 melanoma cells, Abwp significantly inhibited the growth and proliferation of mouse melanoma. Hematoxylin staining showed that the invasion of melanoma cells into the lung tissue of the Abwp-treated group was significantly reduced. Immunohistochemical analysis showed that the expression of proliferation cell nuclear antigen (PCNA), N-cadherin, MMP-9, and Snail in the lung of mouse was significantly inhibited. Immunofluorescence showed that Abwp significantly interfered with the nuclear transcription of NF-κB-p65 in a dose-dependent manner. Collectively, these results showed that Abwp mediated p38 MAPK and NF-κB signaling pathways to inhibit the inflammatory response and malignant proliferation and metastasis of melanoma in mice.

A mixed-mode resin with tryptamine ligand for human serum albumin separation.

Mixed-mode chromatography (MMC) is a new technology that uses specially-designed ligands to improve the adsorption selectivity with multimodal protein-ligand interactions for protein separation. A new MMC resin TA-B-6FF with tryptamine as the functional ligand was prepared and used for human serum albumin (HSA) separation. Adsorption equilibria of plasma-derived HSA (pHSA) were investigated and compared with a commercial tryptophan-based resin (MX-Trp-650m), and the influence of pH and salt addition was studied. The results showed that weak acidic conditions (pH 5.0-7.0) were favorable for HSA adsorption. The maximum adsorption capacity of TA-B-6FF was 141.33mg/g at pH 5.0, which was two times higher than that of MX-Trp-650m. TA-B-6FF also showed better salt-tolerance than MX-Trp-650m. Moreover, TA-B-6FF was used to separate recombinant HSA (rHSA) from Pichia pastoris culture broth. The results indicated that rHSA could be directly captured by TA-B-6FF without dilution or pH adjustment. High purity (87.75%) of rHSA monomer could be obtained with a recovery of 98.53% through two-step elution process. Total content of rHSA monomer and degraded fragment was 99.75%, the removal of host cell proteins reached about 90%. The results demonstrate that new TA-B-6FF resin has a great potential for rHSA purification directly from the complex fermentation broth.