Romidepsin alone or in combination with anti-CD20 chimeric antigen receptor expanded natural killer cells targeting Burkitt lymphoma in vitro and in immunodeficient mice

Abstract

Facilitating the development of alternative targeted therapeutic strategies is urgently required to improve outcome or circumvent chemotherapy resistance in children, adolescents, and adults with recurrent/refractory de novo mature B-cell (CD20) non-Hodgkin lymphoma, including Burkitt lymphoma (BL). Romidepsin, a histone deacetylase inhibitor (HDACi), has been used to treat cutaneous T-cell lymphoma. We have demonstrated the significant anti-tumor effect of anti-CD20 chimeric antigen receptor (CAR) modified expanded peripheral blood natural killer (exPBNK) against rituximab-sensitive and -resistant BL. This study examined the anti-tumor activity of romidepsin alone and in combination with anti-CD20 CAR exPBNKs against rituximab-sensitive and -resistant BL and. We found that romidepsin significantly inhibited both rituximab-sensitive and -resistant BL cell proliferation (P< 0.001) and induced cell death in rituximab-sensitive Raji (P < 0.001) and cell cycle arrest in rituximab-resistant Raji-2R and Raji-4RH (P < 0.001). Consistent with observations, we also found romidepsin significantly inhibited the growth of rituximab-sensitive and -resistant BL in BL xenografted NSG mice. We also demonstrated that romidpesin significantly induced the expression of Natural Killer Group 2, Member D (NKG2D) ligands MICA/B in both rituximab-sensitive and -resistant BL cells (P< 0.001) resulting in enhancement of exPBNK cytotoxicity through NKG2D. Finally, we observed the combination of romidepsin and anti-CD20 CAR exPBNK significantly induced cell death in BL cells, reduced tumor burden and enhanced survival in humanized BL xenografted NSG mice (p < 0.05). Our data suggests that romidepsin is an active HDAC inhibitor that also potentiates expanded NK and anti-CD20 CAR exPBNK activity against rituximab-sensitive and -resistant BL.

Role of HDACs in normal and malignant hematopoiesis

“…Hence, combining HDACis with other chemotherapeutic agents is considered to be an effective way to enhance tumor drug sensitivity by improving the cellular efficacy and toxicity of HDACis to tumor cells [116][117][118][119][120][121][122][123][124][125] (Table 3 and Table 4). To date, the different mechanisms of HDACis combined with chemotherapeutic agents such as topoisomerase inhibitors, platinumbased chemotherapeutics, proteasome inhibitors, tyrosine kinase pathway inhibitors and epigenetic modifiers for advanced or drug-resistant hematological malignancies include (1) acetylating histones and inducing p21-CDK-mediated cell cycle arrest; (2) inducing apoptosis by regulating the expression of pro-and antiapoptotic genes through the intrinsic or extrinsic pathway; (3) inducing DNA damage and oxidative stress; (4) activating BTK (in CLL) or inhibiting ERK (in MM) and AKT (in CML) signaling pathways; and (5) regulating the expression of drug resistance-related molecules, such as downregulating BCR-ABL and upregulating Bim in hematological malignancies and downregulating CD44 in multiple myeloma (MM), NF-κB in ALL, γ-catenin in CML, and BRCA1, CHK1 and RAD51 in AML [126][127][128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144][145]. Specific combination strategies and their corresponding mechanisms are summarized in Table 3 [146][147][148]…”

Ibrutinib significantly inhibited Bruton’s tyrosine kinase (BTK) phosphorylation,in-vitro proliferation and enhanced overall survival in a preclinical Burkitt lymphoma (BL) model

“…Raji and Ramos human BL cell lines were purchased from ATCC and cultured under RPMI1640 supplemented with 10% Fetal Bovine Serum and 2mM Glutamine in a 37°C incubator at 5% CO 2 as we have previously described. 44…”

CAR-Expressing Natural Killer Cells for Cancer Retargeting

“…Although CD20-directed NK cells – both stably transduced NK-92 and mRNA-transfected PB-NK cells – showed in vivo anti-tumour activity in localised tumour xenograft mouse models [27, 28], their transfer into clinical trials has not been successful yet. More recently, combination therapy of anti-CD20-CAR mRNA electroporated PB-NK cells and romidepsin was shown to induce synergistic anti-tumour effects both in vitro and in vivo using a localised Raji lymphoma model [28]. …”