Modulating Cholesterol Metabolism via ACAT1 Knockdown Enhances Anti-B-Cell Lymphoma Activities of CD19-Specific Chimeric Antigen Receptor T Cells by Improving the Cell Activation and Proliferation

Abstract

CD19-specific CAR-T immunotherapy has been extensively studied for the treatment of B-cell lymphoma. Recently, cholesterol metabolism has emerged as a modulator of T lymphocyte function and can be exploited in immunotherapy to increase the efficacy of CAR-based systems. Acetyl-CoA acetyltransferase 1 (ACAT1) is the major cholesterol esterification enzyme. ACAT1 inhibitors previously shown to modulate cardiovascular diseases are now being implicated in immunotherapy. In the present study, we achieved knockdown of ACAT1 in T cells via RNA interference technology by inserting ACAT1-shRNA into anti-CD19-CAR-T cells. Knockdown of ACAT1 led to an increased cytotoxic capacity of the anti-CD19-CAR-T cells. In addition, more CD69, IFN-γ, and GzmB were expressed in the anti-CD19-CAR-T cells. Cell proliferation was also enhanced in both antigen-independent and antigen-dependent manners. Degranulation was also improved as evidenced by an increased level of CD107a. Moreover, the knockdown of ACAT1 led to better anti-tumor efficacy of anti-CD19 CAR-T cells in the B-cell lymphoma mice model. Our study demonstrates novel CAR-T cells containing ACAT1 shRNA with improved efficacy compared to conventional anti-CD19-CAR-T cells in vitro and in vivo.

shRNA-mediated gene silencing of HDAC11 empowers CAR-T cells against prostate cancer

“…Enhancing the efficacy of CAR-T cell therapy through RNAi has been done by our group against pancreatic and prostate (cancer) previously ( 7 , 25 ). While targeting pancreatic cancer with NKG2D-targeting CAR-T cells, we demonstrated that downregulation of 4.1R could enhance CAR-T therapy efficacy.…”

“…An improved therapeutic outcome was observed in 4.1R-silencing CAR-T cells ( 7 ). Additionally, in prostate cancer, CAR-T cells were empowered by downregulating the cholesterol esterification enzyme ACAT1 which was also achieved through shRNA technology ( 25 ). In current study, we designed four shRNA sequences for HDAC11 and chose the one giving the best interference efficiency.…”

The Pan-Cancer Analysis Uncovers the Prognostic and Immunotherapeutic Significance of CD19 as an Immune Marker in Tumor

“…The B-cell immunoglobulin superfamily's signaling receptor, CD19, is a transmembrane protein involved in regulating B-cell activation in an antigen-dependent manner. 11 CD19 has a high lineage-specific expression across various stages of B-cell maturation. 12 Almost all B-cell lines express this protein, yet its expression is limited in both normal and malignant B-cell lines and is not expressed in multilineage, myeloid, erythroid, or megakaryocytic progenitors, indicating CD19 is a desirable target in B-cell malignancies.…”