The mannose-binding protein from Agaricus bisporus inhibits the growth of MDA-MB-231 spheroids.

Abstract

A mannose-binding protein from the mushroom Agaricus bisporus (Abmb) inhibits the growth of MDA-MB-231 cells, which is of an aggressive breast cancer subtype. This ability was observed in a monolayer cell (2D) culture setup, which often is unable to capture changes in cell morphology, polarity and division. That shortcoming may overestimate Abmb potency for its development as a pharmaceutical agent and its use in a therapy. Hence, Abmb's inhibition to the cell growth was performed in the 3D cell (spheroid) culture, which is more representative to the situation in vivo. The result showed that, although the presence of Abmb at ~14.7 μM already disrupted the MDA-MB-231 cell morphology in the 2D culture, its presence at ~16.5 μM only ceased the growth of the MDA-MB-231 spheroid. Further, Abmb is unique because structurally it belongs to the R-type lectin (RTL) family; most of mannose-binding protein is of the C-type lectin (CTL). As the natural ligand of Abmb is unknown thus the mechanism of action is unclear, Abmb effect on the cancer cells was assessed via observation of the altered expression of genes involved in the Wnt/β-catenin signalling, which is one of the canonical pathways in the proliferation of cancer cells. The results suggested that Abmb did not alter the pathway upon exerting its anti-proliferative activity to the MDA-MB-231 cells.