Carcinoma-associated fibroblasts (CAFs) are abundant and heterogeneous stromal cells in tumor microenvironment that are critically involved in cancer progression. Here, we demonstrate that two cell-surface molecules, CD10 and GPR77, specifically define a CAF subset correlated with chemoresistance and poor survival in multiple cohorts of breast and lung cancer patients. CD10GPR77 CAFs promote tumor formation and chemoresistance by providing a survival niche for cancer stem cells (CSCs). Mechanistically, CD10GPR77 CAFs are driven by persistent NF-κB activation via p65 phosphorylation and acetylation, which is maintained by complement signaling via GPR77, a C5a receptor. Furthermore, CD10GPR77 CAFs promote successful engraftment of patient-derived xenografts (PDXs), and targeting these CAFs with a neutralizing anti-GPR77 antibody abolishes tumor formation and restores tumor chemosensitivity. Our study reveals a functional CAF subset that can be defined and isolated by specific cell-surface markers and suggests that targeting the CD10GPR77 CAF subset could be an effective therapeutic strategy against CSC-driven solid tumors.

Highlights d A distinct B cell subset emerges in tumors after chemotherapy d B cells elicit anti-tumor T cell immunity by ICOSL d Complement signals initiated by immunogenic cell death shape B cell phenotypes d Tumor CD55 expression determines the opposite effects of B cells in tumors

Prodigiosin, a natural red pigment produced by numerous bacterial species, has exhibited promising anticancer activity; however, the molecular mechanisms of action of prodigiosin on malignant cells remain unclear. Aberrant activation of the Wnt/β-catenin signaling cascade is associated with numerous human cancers. In this study, we identified prodigiosin as a potent inhibitor of the Wnt/ β-catenin pathway. Prodigiosin blocked Wnt/β-catenin signaling by targeting multiple sites of this pathway, including the lowdensity lipoprotein-receptor-related protein (LRP) 6, Dishevelled (DVL), and glycogen synthase kinase-3β (GSK3β). In breast cancer MDA-MB-231 and MDA-MB-468 cells, nanomolar concentrations of prodigiosin decreased phosphorylation of LRP6, DVL2, and GSK3β and suppressed β-catenin-stimulated Wnt target gene expression, including expression of cyclin D1. In MDA-MB-231 breast cancer xenografts and MMTV-Wnt1 transgenic mice, administration of prodigiosin slowed tumor progression and reduced the expression of phosphorylated LRP6, phosphorylated and unphosphorylated DVL2, Ser9 phosphorylated GSK3β, active β-catenin, and cyclin D1. Through its ability to inhibit Wnt/β-catenin signaling and reduce cyclin D1 levels, prodigiosin could have therapeutic activity in advanced breast cancers.prodigiosin | Wnt/beta-catenin signaling | breast cancer | LRP6 | Dishevelled (DVL)

BackgroundGigantol is a bibenzyl compound derived from several medicinal orchids. This biologically active compound has been shown to have promising therapeutic potential against cancer cells, but its mechanism of action remains unclear.MethodsThe inhibitory effect of gigantol on Wnt/β-catenin signaling was evaluated with the SuperTOPFlash reporter system. The levels of phosphorylated low-density lipoprotein receptor related protein 6 (LRP6), total LRP6 and cytosolic β-catenin were determined by Western blot analysis. The expression of Wnt target genes was analyzed using real-time PCR. Cell viability was measured with a MTT assay. The effect of gigantol on cell migration was examined using scratch wound-healing and transwell migration assays.ResultsGigantol decreased the level of phosphorylated LRP6 and cytosolic β-catenin in HEK293 cells. In breast cancer MDA-MB-231 and MDA-MB-468 cells, treatment with gigantol reduced the level of phosphorylated LRP6, total LRP6 and cytosolic β-catenin in a dose-dependent manner, resulting in a decrease in the expression of Wnt target genes Axin2 and Survivin. We further demonstrated that gigantol suppressed the viability and migratory capacity of breast cancer cells.ConclusionGigantol is a novel inhibitor of the Wnt/β-catenin pathway. It inhibits Wnt/β-catenin signaling through downregulation of phosphorylated LRP6 and cytosolic β-catenin in breast cancer cells.

No abstract