Arsenic trioxide and triptolide synergistically induce apoptosis in the SKM‑1 human myelodysplastic syndrome cell line

Role of reactive oxygen species in myelodysplastic syndromes

Reactive oxygen species (ROS) serve as typical metabolic byproducts of aerobic life and play a pivotal role in redox reactions and signal transduction pathways. Contingent upon their concentration, ROS production not only initiates or stimulates tumorigenesis but also causes oxidative stress (OS) and triggers cellular apoptosis. Mounting literature supports the view that ROS are closely interwoven with the pathogenesis of a cluster of diseases, particularly those involving cell proliferation and differentiation, such as myelodysplastic syndromes (MDS) and chronic/acute myeloid leukemia (CML/AML). OS caused by excessive ROS at physiological levels is likely to affect the functions of hematopoietic stem cells, such as cell growth and self-renewal, which may contribute to defective hematopoiesis. We review herein the eminent role of ROS in the hematological niche and their profound influence on the progress of MDS. We also highlight that targeting ROS is a practical and reliable tactic for MDS therapy.

The efficacy and adverse events of arsenic trioxide for the patients with myelodysplastic syndrome: a systematic review and component network meta-analysis

BACKGROUND

Arsenic trioxide (ATO) might be effective for myelodysplastic syndrome (MDS) by apoptosis induction and demethylation. But ATO has not been widely recommended for small sample and conflicting conclusion of existing trials. This review aimed to systematically evaluate the efficacy of regimens containing ATO for the MDS and explore optimal combination.

METHOD

Randomized clinical trials (RCTs) about ATO regimens were retrieved from China National Knowledge Infrastructure, Embase and PubMed. With odds ratio (OR) as the effect size, network meta-analysis (NMA) and component network meta-analysis (CNMA) were conducted by R and 'netmeta' package, after study selection, quality assessment and data extraction.

RESULT

Thirty-night RCTs were included with a total of 2125 patients, including 1235 treated by ATO containing regimen. With support therapy alone as reference, no inconsistency and heterogeneity were observed. Although NMA did not demonstrate better efficacy of ATO alone, the result of CNMA indicated that ATO was effective in the improvement of overall remission (ORR) [OR = 2.09(1.61, 2.71)] and complete remission (CR) [OR  = 1.66(1.25, 2.21)]. Five ATO-containing regimens reported could effectively improve ORR, some of them benefit in CR or hematological improvement (HI) as well. ATO + Traditional Chinese Medicine (TCM), ATO + Thalidomide (T)+TCM, ATO + Chemotherapy (Chem)+T + TCM were regarded as the optimal combination, which improved both ORR, CR and HI in theory. ATO did not increase the risk of common adverse events compared to supportive therapy [(OR = 0.90(0.67, 1.21)].

CONCLUSION

ATO may be an effective and well-tolerant option for patients with myelodysplastic syndrome.

Therapeutic strategy of arsenic trioxide in the fight against cancers and other diseases

Arsenic trioxide (ATO) has been recognized as a drug for the treatment of various diseases in traditional medicine for more than two thousand years. Although ATO has recently shown excellent efficacy for the treatment of acute promyelocytic leukemia (APL), it could not provide satisfactory outcomes as a single-agent for the management of non-APL leukemia or different solid tumors. Nevertheless, combination treatment strategies, e.g., ATO with other agents, have shown promising results against different diseases. Here, we introduce in depth the latest evidence and detailed insights into ATO-mediated cures for APL by targeting PML/RARα chimeric protein, followed by the preclinical and clinical efficacy of ATO on various non-APL malignancies and solid tumors. Likewise, the antiviral activity of ATO against human immunodeficiency virus (HIV) and hepatitis C virus (HCV) was also discussed briefly. Our review would provide a clear prospect for the combination of ATO with other agents for treatment of numerous neoplastic diseases, and open a new era in the clinically applicable range of arsenicals.

Decitabine shows synergistic effects with arsenic trioxide against myelodysplastic syndrome cells via endoplasmic reticulum stress-related apoptosis

Most of the International Prognostic Scoring System (IPSS) high-risk patients with myelodysplastic syndrome partly responded to hypomethylating therapy even with transient remission, while arsenic trioxide (ATO) had partial effect in patients with MDS. Therefore, we sought to investigate the effects and possible mechanisms of the combination of ATO and decitabine (DAC) in MDS cells. In our study, the MUTZ-1 and SKM-1 cells were treated with ATO, DAC or both. Cell viability, cell apoptosis, levels of reactive oxygen species (ROS) and expressions of the endoplasmicreticulum (ER) stress-associated genes and proteins were examined. Results showed the combination of ATO and DAC synergistically inhibited the proliferation and induced apoptosis of MDS cells. Through the RNA-sequence and GSEA gene function analysis, ER stress-related pathway played an important role in apoptosis of MDS cells induced by the combination of ATO and DAC. ER stress-related genes DNA damage inducible transcript 3, GRP78, and activating transcription factor-6 were significantly highly expressed in combination group than those in single agent groups; proteins were confirmed by western blot. The levels of ROS significantly increased in the combination group. Furthermore, the apoptosis of (ATO+DAC) group MDS cells could be partially reversed by antioxidant agent N-acetylcysteine, accompanied by decreased expression of intracellular ROS and ER stress-related genes. These results suggested that the combination of ATO and DAC synergistically induced the apoptosis of MDS cells by increased ROS-related ER stress in MDS cells.