Characterization of DAPK1 as a novel transcriptional target of BRMS1

Scinderin promotes glioma cell migration and invasion via remodeling actin cytoskeleton

BACKGROUND

Glioma is one of the most common intracranial tumors, characterized by invasive growth and poor prognosis. Actin cytoskeletal rearrangement is an essential event of tumor cell migration. The actin dynamics-related protein scinderin (SCIN) has been reported to be closely related to tumor cell migration and invasion in several cancers.

AIM

To investigate the role and mechanism of SCIN in glioma.

METHODS

The expression and clinical significance of SCIN in glioma were analyzed based on public databases. SCIN expression was examined using real-time quantitative polymerase chain reaction and Western blotting. Gene silencing was performed using short hairpin RNA transfection. Cell viability, migration, and invasion were assessed using cell counting kit 8 assay, wound healing, and Matrigel invasion assays, respectively. F-actin cytoskeleton organization was assessed using F-actin staining.

RESULTS

SCIN expression was significantly elevated in glioma, and high levels of SCIN were associated with advanced tumor grade and wild-type isocitrate dehydrogenase. Furthermore, SCIN-deficient cells exhibited decreased proliferation, migration, and invasion in U87 and U251 cells. Moreover, knockdown of SCIN inhibited the RhoA/focal adhesion kinase (FAK) signaling to promote F-actin depolymerization in U87 and U251 cells.

CONCLUSION

SCIN modulates the actin cytoskeleton via activating RhoA/FAK signaling, thereby promoting the migration and invasion of glioma cells. This study identified the cancer-promoting effect of SCIN and provided a potential therapeutic target for the treatment of glioma.

microRNA-15b-5p encapsulated by M2 macrophage-derived extracellular vesicles promotes gastric cancer metastasis by targeting BRMS1 and suppressing DAPK1 transcription

BACKGROUND

Extracellular vesicles (EVs) derived from tumor-associated macrophages are implicated in the progression and metastasis of gastric cancer (GC) via the transfer of molecular cargo RNAs. We aimed to decipher the impact of microRNA (miR)-15b-5p transferred by M2 macrophage-derived EVs in the metastasis of GC.

METHODS

Expression of miR-15b-5p was assessed and the downstream genes of miR-15b-5p were analyzed. GC cells were subjected to gain- and loss-of function experiments for miR-15b-5p, BRMS1, and DAPK1. M2 macrophage-derived EVs were extracted, identified, and subjected to co-culture with GC cells and their biological behaviors were analyzed. A lung metastasis model in nude mice was established to determine the effects of miR-15b-5p on tumor metastasis in vivo.

RESULTS

miR-15b-5p was upregulated in GC tissues and cells as well as in M2 macrophage-derived EVs. miR-15b-5p promoted the proliferative and invasive potentials, and epithelial-mesenchymal transition (EMT) of GC cells. M2 macrophage-derived EVs could transfer miR-15b-5p into GC cells where it targeted BRMS1 by binding to its 3'UTR. BRMS1 was enriched in the DAPK1 promoter region and promoted its transcription, thereby arresting the proliferative and invasive potentials, and EMT of GC cells. In vivo experiments demonstrated that orthotopic implantation of miR-15b-5p overexpressing GC cells in nude mice displayed led to enhanced tumor metastasis by inhibiting the BRMS1/DAPK1 axis.

CONCLUSIONS

Overall, miR-15b-5p delivered by M2 macrophage-derived EVs constitutes a molecular mechanism implicated in the metastasis of GC, and may thus be considered as a novel therapeutic target for its treatment.