Cytarabine and EIP co-administration synergistically reduces viability of acute lymphoblastic leukemia cells with high ERG expression

n-3 polyunsaturated fatty acids enhanced efficacy of cytarabine in iron-overloaded NALM-6 cells via apoptotic and oxidative pathways

Despite progress in treating acute lymphoblastic leukemia (ALL), the adverse effects of chemotherapy toxicity and iron overload from transfusions continue to affect patients' quality of life. Polyunsaturated fatty acids (PUFAs) exhibit both antitumor and anti-inflammatory properties in leukemia. This study investigated the influence of n-3 PUFA on the efficacy of cytarabine in cells with iron overload. Iron overload was induced in NALM-6 cells using ferric ammonium citrate (FAC) and quantified through atomic absorption spectroscopy (AAS). The impact of n-3 PUFA on NALM-6 cells' response to cytarabine was evaluated using MTT, lactate dehydrogenase (LDH), apoptosis, and cell cycle assays. Additionally, gene expression analyses were performed on apoptotic, anti-apoptotic, and inflammatory genes, along with oxidative stress markers such as reactive oxygen species (ROS) and malondialdehyde (MDA) levels. The administration of n-3 PUFA significantly enhanced the effectiveness of cytarabine in iron-overloaded NALM-6 cells, leading to increased LDH secretion, elevated apoptosis rates, and G1 phase cell cycle arrest. These effects were associated with the upregulation of apoptotic genes such as P53 and caspase-8, the downregulation of the anti-apoptotic gene Bcl2, and a decrease in the inflammatory gene TNF-α. Furthermore, there was a notable increase in ROS and MDA levels. Overall, n-3 PUFA treatment improved cytarabine's efficacy in iron-overloaded NALM-6 cells by activating apoptotic processes and oxidative stress pathways.

Investigation of the mechanism of USP28-mediated IFITM3 elevation in BCR-ABL-dependent imatinib resistance in CML

Due to resistance and BCR-ABLT315I-mutated, CML remains a clinical challenge. It needs new potential therapeutic targets to overcome CML resistance related to BCR-ABL. Our research revealed that the deubiquitinating enzyme USP28 was highly expressed in BCR-ABL-dependent CML patients. Similarly, a high expression of USP28 was found in the K562 cell line, particularly in the imatinib-resistant strains. Notably, USP28 directly interacted with BCR-ABL. Furthermore, when BCR-ABL and its mutant BCR-ABLT315I were overexpressed in K562-IMR, they promoted the expression of IFITM3. However, when small molecule inhibitors targeting USP28 and small molecule degraders targeting BCR-ABL were combined, they significantly inhibited the expression of IFITM3. The experiments conducted on tumor-bearing animals revealed that co-treated mice showed a significant reduction in tumor size, effectively inhibiting the progression of CML tumors. In summary, USP28 promoted the proliferation and invasion of tumor cells in BCR-ABL-dependent CML by enhancing the expression of IFITM3. Moreover, imatinib resistance might be triggered by the activation of the USP28-BCR-ABL-IFITM3 pathway. Thus, the combined inhibition of USP28 and BCR-ABL could be a promising approach to overcome CML resistance dependent on BCR-ABL.