Romidepsin enhances the cytotoxicity of fludarabine, clofarabine and busulfan combination in malignant T-cells

Abstract

Novel approaches to pre-transplant conditioning are needed to improve treatment of advanced T-cell malignancies. We investigated the synergism of fludarabine (Flu), clofarabine (Clo), busulfan (Bu), and romidepsin (Rom) in T-cell lines and patient-derived cell samples. [Flu+Clo+Bu+Rom] had combination indexes of 0.4–0.5 at ~50% cytotoxicity in PEER and SUPT1 cells, suggesting synergism. Drug exposure resulted in histone modifications, DNA-damage response (DDR), increased reactive oxygen species (ROS), decreased glutathione (GSH) and mitochondrial membrane (MM) potential, and apoptosis. Similar activation of DDR and apoptosis was observed in patient samples. The PI3K-AKT-mTOR, NFκB, Raf-MEK-ERK, JAK-STAT and Wnt/β-catenin pro-survival pathways were inhibited by the 4-drug combination. The SAPK/JNK stress pathway was activated. A novel finding was the down-regulation of the drug transporter MRP1. We propose the following mechanisms of synergism: Flu, Clo and Rom induce histone modifications and chromatin remodeling, exposing DNA to Bu alkylation; the increased production of ROS, due to drug-mediated stress response and decreased GSH, damages the MM causing leakage of pro-apoptotic factors; down-regulation of MRP1 increases intracellular Bu concentration and exacerbates the DDR; and inhibition of multiple survival pathways. Our results provide the basis for a clinical trial to evaluate [Flu+Clo+Bu+Rom] as part of conditioning regimen for refractory T-cell malignancy patients undergoing stem cell transplantation.

Combination of a hypomethylating agent and inhibitors of PARP and HDAC traps PARP1 and DNMT1 to chromatin, acetylates DNA repair proteins, down-regulates NuRD and induces apoptosis in human leukemia and lymphoma cells

“…The presence of the DNA alkylator Bu exacerbates the down-regulation of the NuRD complex and further enhances the cytotoxicity of [Npb+DAC+Rom] (Figure 6 ). The presence of DAC and Rom in the combination may relax chromatin [ 36 ] and make the DNA more susceptible to Bu alkylation. Furthermore, the observed down-regulation of the Bu transporter MRP1/ABCC1 may result in an increased intracellular concentration of the active alkylating agent, resulting in more pronounced DNA damage (Figure 8 ).…”

Compensatory combination of romidepsin with gemcitabine and cisplatin to effectively and safely control urothelial carcinoma

“… 5 , 6 In treating lymphoma or refractory solid tumours, 8–17.5 mg/m 2 Rom is given at days 1, 8, and 15 (Supplementary Table S2 ). 30 , 41 Calculations based on NCI’s Equivalent Surface Area Dosage Conversion Factors 42 suggest that administering 1000 mg/m 2 Gem, 15 mg/m 2 Rom, and 70 mg/m 2 Cis to humans is equivalent to administering 324 mg/kg Gem, 5 mg/kg Rom, and 23 mg/kg Cis to mice (Supplementary Table S2 ). Considering the synergy and toxicity 5 , 41 of Rom+Cis+Gem, we formulated dose-reduced combination regimens containing 20 mg/kg Gem, 1 mg/kg Rom, and/or 5 mg/kg Cis.…”

Paradigm Shifts in Fungal Secondary Metabolite Research: Unusual Fatty Acids Incorporated into Fungal Peptides

“…It was found potently cytotoxic against several human cancer cell lines, but has no effect on normal cells in vivo (Ueda et al, 1994;Valdez et al, 2016). Ngercheumicin D with 3-hydroxy-4-(methylthio)-butanoic acid [140], a depsipeptide macrocycle, was isolated from Photobacterium strains and was active against the nonpathogenic Pseudovibrio denitrificans (Kjaerulff et al, 2013;Adachi et al, 2007).…”