CAGE-miR-140-5p-Wnt1 Axis Regulates Autophagic Flux, Tumorigenic Potential of Mouse Colon Cancer Cells and Cellular Interactions Mediated by Exosomes

Abstract

Although the cancer/testis antigen CAGE has been implicated in tumorigenesis, the molecular mechanisms of CAGE-promoted tumorigenesis remain largely unknown. CT26Flag−CAGE cells, CT26 (mouse colon cancer cells) cells stably expressing CAGE, were established to investigate CAGE-promoted tumorigenesis. Down-regulation of CAGE led to decreased autophagic flux in CT26Flag−CAGE cells. CAGE interacted with Beclin1, a mediator of autophagy. The CT26Flag−CAGE cells showed enhanced autophagosome formation and displayed greater tumor spheroid-forming potential than CT26 cells. MicroRNA array analysis revealed that CAGE decreased the expression of various microRNAs, including miR-140-5p, in CT26 cells. CAGE was shown to bind to the promoter sequences of miR-140-5p. MiR-140-5p inhibition increased the tumorigenic potential of and autophagic flux in CT26 cells. A miR-140-5p mimic exerted negative effects on the tumorigenic potential of CT26Flag−CAGE cells and autophagic flux in CT26Flag−CAGE cells. MiR-140-5p was predicted to bind to the 3′-UTR of Wnt1. CT26Flag−CAGE cells showed higher expression of Wnt1 than CT26 cells. Down-regulation of Wnt1 decreased autophagic flux. Luciferase activity assays showed the direct regulation of wnt1 by miR-140-5p. Tumor tissue derived from the CT26Flag−CAGE cells revealed higher expressions of factors associated with activated mast cells and tumor-associated macrophages than tumor tissue derived from CT26 cells. Culture medium from the CT26Flag−CAGE cells increased autophagic flux in CT26 cells, mast cells and macrophages. Culture medium from the CT26Flag−CAGE cells increased CD163 and autophagic flux in CT26 cells, mast cells, and macrophages in a Wnt1-dependent manner. Exosomes from CT26Flag−CAGE cells increased autophagc flux in CT26 cells, mast cells, and macrophages. Exosomes from CT26Flag−CAGE cells increased the tumorigenic potential of CT26 cells. Wnt1 was shown to be present within the exosomes. Recombinant Wnt1 protein increased autophagic flux in CT26, mast cells, and macrophages. Recombinant wnt1 protein mediated interactions between the CT26 cells, mast cells, and macrophages. Our results showed novel roles for the CAGE-miR-140-5p-Wnt1 axis in autophagic flux and cellular interactions mediated by exosomes.

Retracted Article: Macrophage-derived exosomes mediate osteosarcoma cell behavior by activating AKT signaling

“…25,26 For example, mouse colon cancer cell-derived exosomes carry Wnt1 to mediate autophagic ux and tumorigenic potential. 24 miR-192-5p was shown within exosomes derived from lipotoxic hepatocyte to activate the macrophages. 25 In the present work, macrophage-derived exosomes delivered their cargo content including nucleic acids, proteins and lipids into osteosarcoma cells, further promoting osteosarcoma progression and drug-resistance.…”

Regulation of Wnt Signaling Pathways at the Plasma Membrane and Their Misregulation in Cancer

“…Different microRNAs have been shown to affect CRC tumorigenesis as well. While miR-140-5p and miR-185 target Wnt1 and act as tumor suppressors, miR-410 targets Dkk1 and thus functions as an oncogene in CRC ( Zhang et al, 2018 ; Wang et al, 2019b ; Yeon et al, 2019 ). These findings reveal that miRNAs can be used as prognostic markers and to produce potential therapeutic agents for CRC patients.…”

The CAGE–MiR-181b-5p–S1PR1 Axis Regulates Anticancer Drug Resistance and Autophagy in Gastric Cancer Cells

“…Cancer-associated gene binds to epidermal growth factor receptor (EGFR) and increases self-renewal, in addition to increasing autophagic flux ( Kim et al, 2016 ). The CAGE–miR-140-5p–proto-oncogene Wnt1 axis regulates autophagic flux in colon cancer cells ( Yeon et al, 2019 ). CAGE promotes cellular interactions mediated by exosomes ( Yeon et al, 2019 ).…”