Silencing of matrix metalloprotease-12 delays the progression of castration-resistant prostate cancer by regulating autophagy and lipolysis

Abstract The complex pathogenesis of castration-resistant prostate cancer (CRPC) makes it challenging to identify effective treatment methods. Matrix metalloproteinase (MMP)-12 can degrade elastin as well as various extracellular matrix (ECM) components, which is associated with cancer progression. However, the relationship between MMP-12 and CRPC progression is poorly understood. In this study, we observed the effect of MMP-12 on the progression of CRPC and further explored its potential mechanism of action. High levels of MMP-12 were observed in patients with CRPC. We therefore developed cell co-culture and mouse models to study the function of MMP-12. Silencing MMP-12 in CRPC cells disrupted lipid utilization and autophagy marker expression via the CD36/CPT1 and P62/LC3 pathways, respectively, leading to reduced CRPC cell migration and invasion. Moreover, animal experiments confirmed that MMP-12-knockdown CRPC xenograft tumors exhibited reduced tumor growth, and the mechanisms involved the promotion of cancer cell autophagy and the inhibition of lipid catabolism. According to our results, MMP-12 played important roles in the progression of CRPC by disrupting adipocyte maturation and regulating cancer migration and invasion via the modulation of autophagy and lipid catabolism pathways.

The luciferase reporter system of the MMP12 endogenous promoter for investigating transcriptional regulation of the human MMP12 gene

Background: Matrix metalloproteinase 12 (MMP12), a member of MMPs, can take lots of roles including extracellular matrix component degradation, viral infection, inflammation, tissue remodeling and tumorigenesis. To explore the transcriptional regulation of MMP12 gene, a sensitive luciferase reporter HEK293 cell line for endogenous MMP12 promoter was generated by CRISPR/Cas9 technology. Results: The HEK293-MMP12-T2A-luciferase-KI cell line was successfully established by CRISPR/Cas9 technology. The sequencing results indicated that one allele of the genome was proven to have a site-directed insertion of luciferase gene and another allele of the genome was confirmed to have additional 48 bp insertion in this cell line. The cell line was further demonstrated to be a sensitive reporter of the endogenous MMP12 promoter by applying transcription factors STAT3, AP-1 and SP-1 to the cell line. The reporter cell line was then screened with bioactive small molecule library, and a small molecule Tanshinone I was found to significantly inhibit the transcriptional activity of MMP12 gene in HEK293-MMP12-T2A-luciferase-KI cell line by luciferase activity assay, which was further confirmed to inhibit the expression of MMP12 mRNA in wild-type HEK293 cells. Conclusions: This novel luciferase knock-in reporter system will be helpful for investigating the transcriptional regulation of MMP12 gene and screening the drugs targeting MMP12 gene.

A Subset of Genes Can Distinguish between Bortezomib Responsive Versus Bortezomib Resistant Myeloma.

Despite the widespread use of proteasome inhibitors in the treatment of multiple myeloma, the mechanisms of the anti-myeloma activity and the molecular pathways that execute the tumor cell killing are still unknown. In the present work we compared gene expression profile changes in response to bortezomib treatment of cultured bone marrow samples from patients with bortezomibsensitive versus bortezomib-resistant myeloma. The results showed a pronounced induction of>70 genes including>30 heat shock protein transcripts in both patient groups and therefore debate the anti-tumor action, attributed to the unfolded protein response. In contrast, a subset of 7 genes (MMP12, IL7R, MGST1, C3, CYP27A1, MIR148A and CXXC4) changed only in the samples from the bortezomib-sensitive cases and therefore these tumor-associated genes might serve as predictors of the treatment efficacy, as well as for making of further insights onto the mechanism of action of proteasome inhibitors. In summary, we identified a subset of 7 genes which distinguished in our small series betweensensitive versus resistant tumor cells to bortezomib, which requires further assessment in a larger cohort of patients.