[Inhibitory Effect of Simvastatin Combined with Doxorubicin on Biological Functions of Diffuse Large B-Cell Lymphoma...

To explore the effect of simvastatin monotherapy or in combination with doxorubicin on diffuse large B-cell lymphoma (DLBCL) cells and its possible molecular mechanisms.

The differences in the expression levels of genes and proteins related to the mevalonate (MVA) pathway between DLBCL tissues and reactive lymph node hyperplasia tissues were compared via database analysis, as well as their effects on the prognosis. CCK-8 assay was used to detect the effect of simvastatin and doxorubicin on the viability of different subtypes of DLBCL cells, EdU was used to detect cell proliferation, flow cytometry was used to detect apoptosis, and Western blot was used to detect related protein and signaling pathway proteins.

The expression levels of MVA pathway-related genes were increased in tumor tissues of DLBCL patients through the TCGA database, and the median overall survival time of DLBCL patients in HMGCR high expression group was shorter (all P < 0.05). Meanwhile, according to The Human Protein Atlas database, HMGCR protein was significantly high expressed in DLBCL tumor tissue compared with normal tissue. The viability of DLBCL cell lines treated with simvastatin or doxorubicin monotherapy was decreased in time- and concentration-dependent manner, and could be further inhibited by simvastatin combined with doxorubicin especially in GCB subtype cell lines. Both simvastatin and doxorubicin could inhibit the proliferation of DLBCL cell lines, and their combination further suppressed dramatically. Both the two drugs promoted apoptosis in DLBCL cell lines, and the apoptosis was further increased after their combination. Compared with monotherapy, the expression of HMGCR protein and apoptosis-related protein Bcl-2 was further decreased but cleaved-caspase3 and Bax increased after combination therapy. Meanwhile, the expression level of phosphorylated proteins in PI3K-Akt pro-survival signaling pathway were decreased especially in GCB subtype cell lines.

HMGCR, the protein associated with cholesterol synthesis pathway, is highly expressed in DLBCL tumor tissues and indicates poor prognosis. Simvastatin, a lipid-lowering drug, combined with doxorubicin can further affect the survival of DLBCL tumor cells at the cellular level.