Genetic variations in DNA excision repair pathway contribute to the chemosensitivity and prognosis of acute myeloid leukemia.

Acute myeloid leukemia (AML) is a hematologic malignancy with a high recurrence rate and poor long-term prognosis. DNA excision repair systems, such as base excision repair (BER) and nucleotide excision repair (NER), play a major role in maintaining genomic stability and integrity. Further intensive investigations are necessary to uncover additional AML prognosis loci. In this study, we analyzed 16 candidate SNPs within NER and BER pathways in AML patients. Our results showed the GT/GG genotype of the XPC rs2228001 polymorphism was significantly associated with WBC count in dominant models (OR = 0.41, 95 % CI = 0.18-0.96, p = 0.039). Additionally, the rs25487 and rs3213245 SNPs in the XRCC1 gene, in both co-dominant and dominant models, were significantly associated with PLT count in AML (p < 0.05). The GG genotype of rs1130409 in APEX1 was more prone to adverse cytogenetics in both the codominant and recessive models (p < 0.05). Furthermore, the GA genotypes of ERCC8 rs158572 in codominant model was significantly correlated with refractory group (p < 0.05). ERCC8 rs158572 and XRCC1 rs3213245 in both codominant and dominant models were significantly correlated with the MRD positivity (p < 0.05). Kaplan-Meier analysis revealed an link between overall survival (OS) and the co-dominant, dominant, and recessive models of rs2228001 in XPC. Additionally, patients with the GG and GT/GG genotype in the co-dominant, dominant model and recessive model in XPC rs2228001 exhibited significantly longer survival (p < 0.05). Multivariate Cox analyses indicated that rs2228001 in both co-dominant and dominant models were independent favorable factors impacting patient OS (OR < 1). Our findings suggest that genetic polymorphisms in DNA excision repair pathway genetic polymorphisms contribute to the chemosensitivity and prognosis of acute myeloid leukemia.

circFAM193B interaction with PRMT6 regulates AML leukemia stem cells chemoresistance through altering the oxidative metabolism and lipid peroxidation.

Most forms of chemotherapy for acute myeloid leukemia (AML) are often ineffective in eliminating leukemic stem cells (LSCs), as their underlying mechanisms remain unclear. Here, we have identified circFAM193B, which regulates the redox biology of LSCs and is associated with unfavorable outcomes in AML patients. In vitro and in vivo assays suggested that circFAM193B significantly inhibits LSCs chemotherapy resistance and AML progression. Knockdown circFAM193B enhances mitochondrial OXPHOS function and inhibits the accumulation of reactive oxygen species and lipid peroxidation mediated by chemotherapy, which protects AML cells from oxidative stress-induced cell death. Mechanistically, circFAM193B physically interacts with arginine methyltransferase PRMT6 catalytic domain and enhances the transcription efficiency of key lipid peroxidation factor ALOX15 by decreasing H3R2me2a modification. In summary, we have identified circFAM193B was downregulated in LSCs to promote the survival of LSC by modulating energy metabolism and the redox balance in the postchemotherapy persistence of LSC. Our studies provide a conceptual advance and biological insights regarding the drug resistance of LSCs via circRNA mediated PRMT6-deposited methylarginine signaling.

Propionate promotes ferroptosis and apoptosis through mitophagy and ACSL4-mediated ferroptosis elicits anti-leukemia immunity.

Short-chain fatty acids (SCFAs), particularly propionate and butyrate, have been reported in many cancers. However, the relationship between propionate and acute myeloid leukemia (AML) remains unclear. Additionally, Acyl-CoA synthetase long chain family member 4 (ACSL4) has been reported to regulate immunity in solid tumors, but there are still many gaps to be filled in AML. Here, we discovered the underlying mechanism of propionate and ACSL4-mediated ferroptosis for immunotherapy. Our results showed that the level of propionate in the AML patients' feces was decreased, which was correlated to gut microbiota dysbiosis. Moreover, we demonstrated that propionate suppressed AML progression both in vivo and in vitro. In mechanism, propionate induced AML cells apoptosis and ferroptosis. The imbalance of reactive oxygen species (ROS) and redox homeostasis induced by propionate caused mitochondrial fission and mitophagy, which enhanced ferroptosis and apoptosis. Furthermore, ACSL4-mediated ferroptosis caused by propionate increased the immunogenicity of AML cells, induced the release of damage-associated molecular patterns (DAMPs), and promoted the maturation of dendritic cells (DCs). The increased level of immunogenicity due to ferroptosis enable propionate-based whole-cell vaccines to activate immunity, thus further facilitating effective killing of AML cells. Collectively, our study uncovers a crucial role for propionate suppresses AML progression by inducing ferroptosis and the potential mechanisms of ACSL4-mediated ferroptosis in the regulation of AML immunity.

Analysis of gene mutation characteristics and its correlation with prognosis in patients with myelodysplastic syndromes.

Gene mutations are a pivotal component of the pathogenesis of MDS, and they hold profound prognostic significance for predicting treatment responses and survival outcomes. However, reports about mutation patterns in Chinese MDS patients are limited. In this study, we analyzed the genetic mutation of 23 genes in 231 patients with MDS using next-generation sequencing (NGS) technology, and explored the characteristics of gene mutations in MDS patients and their associations with clinical outcomes, survival, and transformation outcomes. Our results showed that 68.83% patients had at least one gene mutation, and the most common mutations were ASXL1 (21.65%), SF3B1 (17.32%), U2AF1 (16.02%), TET2 (14.72%) and TP53 (8.66%). We also showed that the genetic mutations of TP53, U2AF1 and DNMT3A are independent risk factors for death in patients with MDS, and the ETV6 gene mutation was an independent risk factor for the transformation of MDS patients to AML through the univariate and multivariate Cox regression analysis model. Additionally, the study developed a risk score based on gene mutation data that demonstrated robust predictive capability and stability for the overall survival of MDS patients. Our research provided a strong theoretical basis for the establishment of personalized treatment and prognostic risk assessment models for Chinese MDS patients.

Mitochondrial transfer in hematological malignancies.

Mitochondria are energy-generated organelles and take an important part in biological metabolism. Mitochondria could be transferred between cells, which serves as a new intercellular communication. Mitochondrial transfer improves mitochondrial defects, restores the biological functions of recipient cells, and maintains the high metabolic requirements of tumor cells as well as drug resistance. In recent years, it has been reported mitochondrial transfer between cells of bone marrow microenvironment and hematological malignant cells play a critical role in the disease progression and resistance during chemotherapy. In this review, we discuss the patterns and mechanisms on mitochondrial transfer and their engagement in different pathophysiological contexts and outline the latest knowledge on intercellular transport of mitochondria in hematological malignancies. Besides, we briefly outline the drug resistance mechanisms caused by mitochondrial transfer in cells during chemotherapy. Our review demonstrates a theoretical basis for mitochondrial transfer as a prospective therapeutic target to increase the treatment efficiency in hematological malignancies and improve the prognosis of patients.

Hematopoietic stem cells suppress proliferation and enhance differentiation of leukemia cells through regulating apoptotic and inflammatory genes.

PURPOSE: Stem cells are known to play an important role in tumor treatment and many of them have shown tumor-suppressing ability in different cancers; however, whether hematopoietic stem cells (HSCs) have growth-inhibiting effects on leukemia cells has not been fully evaluated. Herein, we aimed to demonstrate the growth-restraining function of HSCs in acute leukemia treatment. METHODS: Cell fusion experiment was conducted by PEG-1500. The viability, proliferation, apoptosis and differentiation of leukemia cells were evaluated by cell counting, CCK-8 and flow cytometry analysis. The morphological changes were imaged using a fluorescence microscope. The expression of genes was detected by quantitative reverse transcription PCR (qRT-PCR). RESULTS: We observed that HSCs and their lytic extracts had the capability to suppress leukemia cells proliferation, promote apoptosis and especially induce acute myelogenous leukemia (AML) cells differentiation, which might have an effect on differentiation therapy to leukemia especially AML treatment. The expression levels of Bcl-2, Survivin decreased and Bax increased following HSCs extracts treatment. Furthermore, the expression of inflammatory cytokines also changed in AML cells which might have to do with the mechanism of HSCs/extracts suppressing effect. CONCLUSION: HSCs and their extracts can suppress the proliferation of leukemia cells and enhance the differentiation of AML cells and using the extracts of HSCs might be a probable therapeutic option for acute leukemia.

The genetic polymorphisms of immune-related genes contribute to the susceptibility and survival of lymphoma.

BACKGROUND: Though immunological abnormalities have been proven involved in the pathogenesis of lymphoma, the underlying mechanism remains unclear. METHODS: We investigated 25 single nucleotide polymorphisms (SNPs) of 21 immune-related genes and explored their roles in lymphoma. The genotyping assay of the selected SNPs was used by the Massarray platform. Logistic regression and Cox proportional hazards models were used to analyze the associations of SNPs and the susceptibility of lymphoma or clinical characteristics of lymphoma patients. In addition, Least Absolute Shrinkage and Selection Operator regression was used to further analyze the relationships with the survival of lymphoma patients and candidate SNPs, and the significant difference between genotypes was verified by the expression of RNA. RESULTS: By comparing 245 lymphoma patients with 213 healthy controls, we found eight important SNPs related to the susceptibility of lymphoma, which were involved in JAK-STAT, NF-κB and other functional pathways. We further analyzed the relationships between SNPs and clinical characteristics. Our results showed that both IL6R (rs2228145) and STAT5B (rs6503691) significantly contributed to the Ann Arbor stages of lymphoma. And the STAT3 (rs744166), IL2 (rs2069762), IL10 (rs1800871), and PARP1 (rs907187) manifested a significant relationship with the peripheral blood counts in lymphoma patients. More importantly, the IFNG (rs2069718) and IL12A (rs6887695) were associated with the overall survival (OS) of lymphoma patients remarkably, and the adverse effects of GC genotypes could not be offset by Bonferroni correction for multiple comparison in rs6887695 especially. Moreover, we determined that the mRNA expression levels of IFNG and IL12A were significantly decreased in patients with shorter-OS genotypes. CONCLUSIONS: We used multiple methods of analysis to predict the correlations between lymphoma susceptibility, clinical characteristics or OS with SNPs. Our findings reveal that immune-related genetic polymorphisms contribute to the prognosis and treatment of lymphoma, which may serve as promising predictive targets.

EIF4A3-induced Circ_0001187 facilitates AML suppression through promoting ubiquitin-proteasomal degradation of METTL3 and decreasing m6A modification level mediated by miR-499a-5p/RNF113A pathway.

Aberrant expression of circRNAs has been proven to play a crucial role in the progression of acute myeloid leukemia (AML); however, its regulatory mechanism remains unclear. Herein, we identified a novel circRNA, Circ_0001187, which is downregulated in AML patients, and its low level contributes to a poor prognosis. We further validated their expression in large-scale samples and found that only the expression of Circ_0001187 was significantly decreased in newly diagnosed (ND) AML patients and increased in patients with hematological complete remission (HCR) compared with controls. Knockdown of Circ_0001187 significantly promoted proliferation and inhibited apoptosis of AML cells in vitro and in vivo, whereas overexpression of Circ _0001187 exerted the opposite effects. Interestingly, we found that Circ_0001187 decreases mRNA m6A modification in AML cells by enhancing METTL3 protein degradation. Mechanistically, Circ_0001187 sponges miR-499a-5p to enhance the expression of E3 ubiquitin ligase RNF113A, which mediates METTL3 ubiquitin/proteasome-dependent degradation via K48-linked polyubiquitin chains. Moreover, we found that the low expression of Circ _0001187 is regulated by promoter DNA methylation and histone acetylation. Collectively, our findings highlight the potential clinical implications of Circ _0001187 as a key tumor suppressor in AML via the miR-499a-5p/RNF113A/METTL3 pathway.

Clinical and prognostic profile of SRSF2 and related spliceosome mutations in patients with acute myeloid leukemia.

BACKGROUND: Mutations in splicing factor (SF) genes are frequently detected in myelodysplastic syndrome, but their clinical and prognostic relevance in acute myeloid leukemia (AML) have rarely been reported. METHODS: A total of 368 newly diagnosed non-M3 AML patients were included in this study. Next generation sequencing including four SF genes was performed on the genomicDNA. The clinical features and survival were analyzed using statistical analysis. RESULTS: We found that 64 of 368 patients harbored SF mutations. The SF mutations were much more frequently found in older or male patients. SRSF2 mutations were shown obviously co-existed with IDH2 mutation. The level of measurable residual disease after first chemotherapy was higher in SF-mutated patients compared to that in SF-wild patients, while the complete remission rate was significantly decreased. And the overall survival of SF-mutated patients was shorter than that of SF-wild patients. Moreover, our multivariable analysis suggests that the index of male, Kit mutation or ZRSR2 mutation was the independent risk factor for overall survival. SRSF2mut was associated with older age, higher proportion of peripheral blasts or abnormal cell proportion by flow cytometry. CONCLUSION: SF mutation is a distinct subgroup of AML frequently associated with clinic-biological features and poor outcome. SRSF2mut could be potential targets for novel treatment in AML.

Chenodeoxycholic acid suppresses AML progression through promoting lipid peroxidation via ROS/p38 MAPK/DGAT1 pathway and inhibiting M2 macrophage polarization.

PURPOSE: Bile acids are steroid synthesized in liver, which are essential for fat emulsification, cholesterol excretion and gut microbial homeostasis. However, the role of bile acids in leukemia progression remains unclear. We aim at exploring the effects and mechanisms of chenodeoxycholic acid (CDCA), a type of bile acids, on acute myeloid leukemia (AML) progression. RESULTS: Here, we found that CDCA was decreased in feces and plasma of AML patients, positively correlated with the diversity of gut microbiota, and negatively associated with AML prognosis. We further demonstrated that CDCA suppressed AML progression both in vivo and in vitro. Mechanistically, CDCA bound to mitochondria to cause mitochondrial morphology damage containing swelling and reduction of cristae, decreased mitochondrial membrane potential and elevated mitochondrial calcium level, which resulted in the production of excessive reactive oxygen species (ROS). Elevated ROS further activated p38 MAPK signaling pathway, which collaboratively promoted the accumulation of lipid droplets (LDs) through upregulating the expression of the diacylglycerol O-acyltransferase 1 (DGAT1). As the consequence of the abundance of ROS and LDs, lipid peroxidation was enhanced in AML cells. Moreover, we uncovered that CDCA inhibited M2 macrophage polarization and suppressed the proliferation-promoting effects of M2 macrophages on AML cells in co-cultured experiments. CONCLUSION: Our findings demonstrate that CDCA suppresses AML progression through synergistically promoting LDs accumulation and lipid peroxidation via ROS/p38 MAPK/DGAT1 pathway caused by mitochondrial dysfunction in leukemia cells and inhibiting M2 macrophage polarization.