Generation of Inducible BCL11B Knockout in TAL1/LMO1 Transgenic Mouse T Cell Leukemia/Lymphoma Model.

The B-cell CLL/lymphoma 11B gene (BCL11B) plays a crucial role in T-cell development, but its role in T-cell malignancies is still unclear. To study its role in the development of T-cell neoplasms, we generated an inducible BCL11B knockout in a murine T cell leukemia/lymphoma model. Mice, bearing human oncogenes TAL BHLH Transcription Factor 1 (TAL1; SCL) or LIM Domain Only 1 (LMO1), responsible for T-cell acute lymphoblastic leukemia (T-ALL) development, were crossed with BCL11B floxed and with CRE-ER/lox mice. The mice with a single oncogene BCL11Bflox/floxCREtg/tgTAL1tg or BCL11Bflox/floxCREtg/tgLMO1tg were healthy, bred normally, and were used to maintain the mice in culture. When crossed with each other, >90% of the double transgenic mice BCL11Bflox/floxCREtg/tgTAL1tgLMO1tg, within 3 to 6 months after birth, spontaneously developed T-cell leukemia/lymphoma. Upon administration of synthetic estrogen (tamoxifen), which binds to the estrogen receptor and activates the Cre recombinase, the BCL11B gene was knocked out by excision of its fourth exon from the genome. The mouse model of inducible BCL11B knockout we generated can be used to study the role of this gene in cancer development and the potential therapeutic effect of BCL11B inhibition in T-cell leukemia and lymphoma.

TNFAIP3 mutation may be associated with favorable overall survival for patients with T-cell lymphoma.

BACKGROUND: T-cell lymphoma (TCL) is highly aggressive and has a poor prognosis; thus, it is worth exploring biomarkers that may predict clinical outcomes and investigate their potential role in developing targeted therapies. In this study, we characterized the mutation pattern of tumor necrosis factor-alpha-inducing protein 3 (TNFAIP3) and its role in the prognosis of TCL patients. METHODS: Coding sequence (CDS) mutations in TNFAIP3 in TCL patients was explored using exome-sequencing data from 79 patients in our center (Guangdong Provincial People's Hospital, GDPH) and 544 samples from the Catalogue of Somatic Mutations in Cancer (COSMIC) database. Additionally, non-CDS mutations in TNFAIP3 in 41 TCL patients from our center (JNU) were investigated by polymerase chain reaction (PCR) and Sanger sequencing. Furthermore, non-CDS mutations in TNFAIP3 in 47 TCL patients from Gene Expression Omnibus (GEO) dataset were explored. RESULTS: In the COSMIC database, TNFAIP3 mutations in TCL patients were located in the CDS, and the overall mutation frequency was 2.2%. However, TNFAIP3 mutations were not detected in the CDS of any of the samples in our center's datasets. Interestingly, non-CDS TNFAIP3 mutations were found in 14.6% and 4.3% of TCL patients in the JNU and GSE15842 dataset, respectively. Importantly, there was a clear trend showing that TCL patients with a TNFAIP3 mutation were associated with a longer 5-year restricted mean survival time (RMST) and favorable OS rate compared with those without a TNFAIP3 mutation in the JNU dataset [hazard ratio (HR) = 0.29, 95% confidence interval (CI) 0.07 to 1.31, P = 0.089]. Furthermore, TNFAIP3 mutations significantly correlated with T-cell large granular lymphocytic leukemia (T-LGLL) with a favorable prognosis in the JNU dataset (P = 0.002). Notably, the different mutation patterns of TNFAIP3 when comparing our center and the COSMIC datasets might be due to different ethnic and genetic backgrounds. CONCLUSIONS: To the best of our knowledge, we for the first time describe that TNFAIP3 mutations in non-CDS regions are associated with favorable OS for TCL patients, which might be a potential biomarker for the prognostic stratification of Chinese TCL patients.

TAL1 mediates imatinib-induced CML cell apoptosis via the PTEN/PI3K/AKT pathway.

Chronic myeloid leukemia (CML) is associated with chromosomal translocation t(9; 22), which results in formation of the BCR-ABL oncogene. CML is treated with tyrosine kinase inhibitors (TKIs), which target BCR-ABL, to eradicate BCR-ABL + cells. However, the TKI imatinib (IM) fails to eliminate quiescent leukemia stem cells (LSCs) in CML. In this study, we demonstrate that transcription factor TAL1 is down-regulated in CML LSCs by BCR-ABL, and IM triggers TAL1 mRNA expression. In addition, loss of TAL1 abrogates IM-induced CML cell apoptosis. RNA-seq analysis suggests that TAL1 expression may affect PI3K/AKT pathway. Moreover, depletion of TAL1 inhibits the expression of PTEN, which is a negative regulator of the PI3K/AKT pathway. Our results reveal an unexpected involvement of TAL1 in CML etiology and demonstrate that TAL1 may regulate PTEN expression and lead to inhibition of the PI3K/AKT pathway in the response of CML cells to TKI. These results implicate regulation of PTEN expression as a novel mechanism for the transcriptional regulatory networks of TAL1 in CML.

The c-Myc-regulated lncRNA NEAT1 and paraspeckles modulate imatinib-induced apoptosis in CML cells.

Chronic myeloid leukemia (CML) is a clonal disease characterized by the presence of the constitutively active tyrosine kinase BCR-ABL oncoprotein. Although BCR-ABL is crucially important for pathogenesis and treatment response, it is thought that some additional factors might be involved in the regulation of these processes. Aberrant expression of long noncoding RNAs (lncRNAs) has recently been identified to be involved in various diseases including cancer, suggesting that lncRNAs may play a role in BCR-ABL-mediated CML. In this study, we found that nuclear-enriched abundant transcript 1 (NEAT1), a lncRNA essential for the formation of nuclear body paraspeckles, is significantly repressed in primary CML cells. NEAT1 expression could be restored by inhibiting BCR-ABL expression or its kinase activity in K562 cells. We also demonstrated that NEAT1 is regulated by c-Myc. Knockdown of NEAT1 could promote imatinib (IM)-induced apoptosis, and we demonstrated that the NEAT1-binding paraspeckle protein splicing factor proline/glutamine-rich (SFPQ) is required for NEAT1-mediated apoptosis in K562 cells. RNA-seq analysis revealed that SFPQ regulates cell growth and death pathway-related genes, confirming its function in IM-induced apoptosis. Collectively, these results assign a biological function to the NEAT1 lncRNA in CML apoptosis and may lead to fuller understanding of the molecular events leading to CML.

A distinct set of long non-coding RNAs in childhood MLL-rearranged acute lymphoblastic leukemia: biology and epigenetic target.

Long non-coding RNAs (lncRNAs) have been recently found to be pervasively transcribed in human genome and link to diverse human diseases. However, the expression patterns and regulatory roles of lncRNAs in hematopoietic malignancies have not been reported. Here, we carried out a genome-wide lncRNA expression study in MLL-rearranged acute lymphoblastic leukemia (MLL-r ALL) and established lncRNA/messenger RNA coexpression networks to gain insight into the biological roles of these dysregulated lncRNAs. We detected a number of lncRNAs that were differentially expressed in MLL-r ALL samples compared with MLL-r wild-type and identified unique lncRNA expression patterns between MLL-r subtypes with different translocations as well as between infant MLL-r ALL with other MLL-r ALL patients, suggesting that they might be served as novel biomarkers for the disease. Importantly, several lncRNAs that correspond with membrane protein genes, including a lysosome-associated membrane protein, were identified. No such link between the membrane proteins and MLL-r leukemia has been reported previously. Impressively, the functional analysis showed that several lncRNAs corresponded to the expression of MLL-fusion protein target genes, including HOXA9, MEIS1, etc., while some other associated with histone-related functions or membrane proteins. Further experiments characterize the effect of some lncRNAs on MLL-r leukemia apoptosis and proliferation as the function of the coexpressed HOXA gene cluster. Finally, a set of lncRNAs epigenetically regulated by H3K79 methylation were also discovered. These findings may provide novel insights into the mechanisms of lncRNAs involved in the initiation of MLL-r leukemia. This is the first study linking lncRNAs to leukemogenesis.

Identification of miR-125b targets involved in acute promyelocytic leukemia cell proliferation.

Acute promyelocytic leukemia (APL) is characterized by the presence of the PML-RARα fusion protein. We have previously found that PML-RARα-regulated miR-125b is highly expressed in APL; however, the characteristics of the regulatory effects and mechanisms of miR-125b involved in APL proliferation have yet to be clarified. In this study, we demonstrate that miR-125b promotes the proliferation of APL cells with the involvement of the PI3K/Akt and MAPK signaling pathways. Furthermore, we identified BTG2, MAP3K11, RPS6KA1 and PRDM1 as putative targets of miR-125b, which we verified using luciferase reporter constructs. Moreover, we demonstrate that the expression of miR-125b targets is downregulated in leukemic cells in patients with APL. Thus, our results provide evidence that miR-125b can modulate multiple oncogenic cell proliferation pathways and may be a novel therapeutic target for APL.

A polymethoxyflavone from Laggera pterodonta induces apoptosis in imatinib-resistant K562R cells via activation of the intrinsic apoptosis pathway.

BACKGROUND: Treatment with imatinib mesylate (IM) (a tyrosine kinase inhibitor) is the first line of standard care for patients newly diagnosed with CML. Despite the success of IM and other tyrosine kinase inhibitors (TKIs), chronic myeloid leukemia (CML) remains largely incurable, and a number of CML patients die due to Abl mutation-related drug resistance and blast crisis. 3, 5-Dihydroxy-6, 7, 3'4'-tetramethoxyflavone (DHTMF) is a polymethoxyflavone isolated from Laggera pterodonta which is a herbal medicine used to treat cancer in the Chinese folk. In the previous study, we found DHTMF demonstrated good antiproliferative activities against a number of cancer cell lines and induced the apoptosis of CNE cells in vitro in a time- and dose-dependent manner while exhibiting low cytotoxicity in the two normal cell lines Vero and EVC304. The aim of the present study was to evaluate the proliferation inhibition and apoptosis induced by DHTMF alone and in combination with IM in the IM-resistant CML cell line K562R. METHODS: Cell proliferation was assayed with the cell counting kit-8 (CCK8) method. The apoptosis percentage was determined by flow cytometry (FCM). Mitochondrial transmembrane potential was detected using FCM and confocal laser-scanning microscopy. The level of proteins involved in apoptosis was detected by Western blotting. RESULTS: DHTMF suppressed K562R cell viability in both time- and dose-dependent manners. DHTMF combined with IM enhanced the inhibitory effects and apoptosis in K562R cells as compared with DHTMF alone. DHTMF alone and in combination with IM significantly decreased the mitochondrial membrane potential and increased the levels of cleaved caspase-9, caspase-7, caspase-3, and PARP in K562R cells. CONCLUSIONS: We demonstrated that DHTMF could inhibit IM-resistant K562R cell proliferation and induces apoptosis via the intrinsic mitochondrial apoptotic pathway. These results suggest that DHTMF may be a potential therapeutic drug with lower side effects against IM resistance in CML cells.

Inhibition of long non-coding RNA NEAT1 impairs myeloid differentiation in acute promyelocytic leukemia cells.

BACKGROUND: Acute promyelocytic leukemia (APL) is characterized by the reciprocal translocation t(15;17), which fuses PML with retinoic acid receptor alpha (RARα). Although PML-RARα is crucially important for pathogenesis and responsiveness to treatment, the molecular and cellular mechanisms by which PML-RARα exerts its oncogenic potential have not been fully elucidated. Recent reports have suggested that long non-coding RNAs (lncRNAs) contribute to the precise control of gene expression and are involved in human diseases. Little is known about the role of lncRNA in APL. METHODS: We analyzed NEAT1 expression in APL samples and cell lines by real-time quantitative reverse transcription-PCR (qRT-PCR). The expression of PML-RARα was measured by Western blot. Cell differentiation was assessed by measuring the surface CD11b antigen expression by flow cytometry analysis. RESULTS: We found that nuclear enriched abundant transcript 1 (NEAT1), a lncRNA essential for the formation of nuclear body paraspeckles, is significantly repressed in de novo APL samples compared with those of healthy donors. We further provide evidence that NEAT1 expression was repressed by PML-RARα. Furthermore, significant NEAT1 upregulation was observed during all-trans retinoic acid (ATRA)-induced NB4 cell differentiation. Finally, we demonstrate the importance of NEAT1 in myeloid differentiation. We show that reduction of NEAT1 by small interfering RNA (siRNA) blocks ATRA-induced differentiation. CONCLUSIONS: Our results indicate that reduced expression of the nuclear long noncoding RNA NEAT1 may play a role in the myeloid differentiation of APL cells.

T-cell lymphoma patient harboring BCL11B mutations had favorable overall survival.

BACKGROUND: Molecular genetics serve a critical role in constructing risk stratification for hematological malignancies, but T-cell lymphoma (TCL) still lacks molecular genetic information for supplement risk stratification in predicting the prognosis of TCL patients. In the present study, we characterized the mutation patterns of B-cell leukemia/lymphoma 11B gene (BCL11B) and its prognostic importance in TCL patients. METHODS: BCL11B mutations were characterized based on the data from two datasets, one is from our clinical center (GDPH dataset, n = 79) and the other is from COSMIC dataset (n = 154). RESULTS: The overall mutation rate of BCL11B was 6.4% (15/233) in TCL, and there were no hotspot mutation sites in TCL. Among these mutations, the missense and splice site mutation were significantly prominent. Moreover, TCL patients harboring BCL11B mutations had a favorable overall survival (OS) in our center (GDPH dataset) (adjusted hazard ratio [HR] = .001, p = 0.109), although there were not yet significantly statistical at this point. In addition, TCL patients harboring BCL11B mutation had a longer 5-year restricted mean survival time (RMST) than those without a BCL11B mutation (60 vs. 32 months). Notably, BCL11B mutations were not associated with TCL entities having better prognosis. CONCLUSIONS: BCL11B mutations were associated with favorable clinical outcome for TCL patients; it might be considered as a novel biomarker for TCL prognostic stratification.

BET Inhibitor JQ1 Selectively Reduce Tregs by Upregulating STAT3 and Suppressing PD-1 Expression in Patients with Multiple Myeloma.

Multiple myeloma (MM) stands as a prevalent hematological malignancy, primarily incurable, originating from plasma cell clones. MM's progression encompasses genetic abnormalities and disruptions in the bone marrow microenvironment, leading to tumor proliferation, immune dysfunction, and compromised treatment outcomes. Emerging evidence highlights the critical role of regulatory T cells (Tregs) in MM progression, suggesting that targeting Tregs could enhance immune functionality and treatment efficacy. In this study, a notable increase in Treg proportions within MM patients' bone marrow (BM) compared to healthy individuals is observed. Additionally, it is found that the bromodomain and extraterminal domain (BET) inhibitor JQ1 selectively diminishes Treg percentages in MM patients' BM and reduces TGF-ß1-induced Tregs. This reduction occurs via inhibiting cell viability and promoting apoptosis. RNA sequencing further indicates that JQ1's inhibitory impact on Tregs likely involves upregulating STAT3 and suppressing PD-1 expression. Collectively, these findings suggest JQ1's potential to modulate Tregs, bolstering the immune response in MM and introducing a promising avenue for MM immunotherapy.

Metformin synergizes with gilteritinib in treating FLT3-mutated leukemia via targeting PLK1 signaling.

Fms-like tyrosine kinase 3 (FLT3) mutations, present in over 30% of acute myeloid leukemia (AML) cases and dominated by FLT3-internal tandem duplication (FLT3-ITD), are associated with poor outcomes in patients with AML. While tyrosine kinase inhibitors (TKIs; e.g., gilteritinib) are effective, they face challenges such as drug resistance, relapse, and high costs. Here, we report that metformin, a cheap, safe, and widely used anti-diabetic agent, exhibits a striking synergistic effect with gilteritinib in treating FLT3-ITD AML. Metformin significantly sensitizes FLT3-ITD AML cells (including TKI-resistant ones) to gilteritinib. Metformin plus gilteritinib (low dose) dramatically suppresses leukemia progression and prolongs survival in FLT3-ITD AML mouse models. Mechanistically, the combinational treatment cooperatively suppresses polo-like kinase 1 (PLK1) expression and phosphorylation of FLT3/STAT5/ERK/mTOR. Clinical analysis also shows improved survival rates in patients with FLT3-ITD AML taking metformin. Thus, the metformin/gilteritinib combination represents a promising and cost-effective treatment for patients with FLT3-mutated AML, particularly for those with low income/affordability.

A set of miRNAs that involve in the pathways of drug resistance and leukemic stem-cell differentiation is associated with the risk of relapse and glucocorticoid response in childhood ALL.

Relapse is a major challenge in the successful treatment of childhood acute lymphoblastic leukemia (ALL). Despite intensive research efforts, the mechanisms of ALL relapse are still not fully understood. An understanding of the molecular mechanisms underlying treatment outcome, therapy response and the biology of relapse is required. In this study, we carried out a genome-wide microRNA (miRNA) microarray analysis to determine the miRNA expression profiles and relapse-associated miRNA patterns in a panel of matched diagnosis-relapse or diagnosis-complete remission (CR) childhood ALL samples. A set of miRNAs differentially expressed either in relapsed patients or at diagnosis compared with CR was further validated by quantitative real-time polymerase chain reaction in an independent sample set. Analysis of the predicted functions of target genes based on gene ontology 'biological process' categories revealed that the abnormally expressed miRNAs are associated with oncogenesis, classical multidrug resistance pathways and leukemic stem cell self-renewal and differentiation pathways. Several targets of the miRNAs associated with ALL relapse were experimentally validated, including FOXO3, BMI1 and E2F1. We further investigated the association of these dysregulated miRNAs with clinical outcome and confirmed significant associations for miR-708, miR-223 and miR-27a with individual relapse-free survival. Notably, miR-708 was also found to be associated with the in vivo glucocorticoid therapy response and with disease risk stratification. These miRNAs and their targets might be used to optimize anti-leukemic therapy, and serve as novel targets for development of new countermeasures of leukemia. This fundamental study may also contribute to establish the mechanisms of relapse in other cancers.

TNFAIP3 mutation is an independent poor overall survival factor for patients with T-cell acute lymphoblastic leukemia.

BACKGROUND: It is imperative to explore potential biomarkers for predicting clinical outcome and developing targeted therapies for T-cell acute lymphoblastic leukemia (T-ALL). This study aimed to investigate the mutation patterns of tumor necrosis factor-alpha-inducing protein 3 (TNFAIP3, also known as A20) and its role in the prognosis of T-ALL patients. METHODS: Polymerase chain reaction (PCR) and Sanger sequencing data from T-ALL (n = 49, JNU) and targeted sequencing data from T-ALL (n = 54, NFH) in our clinical center and a publicly available dataset (n = 121, PRJCA002270), were used to detect TNFAIP3 mutation. RESULTS: Three TNFAIP3 single nucleotide polymorphisms (SNPs; g.3033 C > T, g.3910 G > A, and g.3904 A > G) were detected in T-ALL in the JNU dataset, and g.3033 C > T accounted for the highest proportion, reaching 60% (6/10). Interestingly, TNFAIP3 mutation mainly occurred in adults but not pediatric patients in all three datasets (JNU, NFH, and PRJCA002270). T-ALL patients carrying a TNFAIP3 mutation were associated with a trend of poor overall survival (OS) (p = 0.092). Moreover, TNFAIP3 mutation was also an independent factor for OS for T-ALL patients (p = 0.008). Further subgroup analysis suggested that TNFAIP3 mutation predicted poor OS for T-ALL patients who underwent chemotherapy only (p < 0.001), and it was positively correlated with high risk and early T-cell precursor ALL (ETP-ALL) in two independent validation datasets (NFH and PRJCA002270). CONCLUSION: TNFAIP3 mutation mainly occurs in adult T-ALL patients, and it was associated with adverse clinical outcomes for T-ALL patients; thus, it might be a biomarker for prognostic stratification.

CASP1 is a target for combination therapy in pancreatic cancer.

Gemcitabine (GEM) is commonly used as the first-line chemotherapeutic agent for treating pancreatic cancer (PC) patients. However, drug resistance is a major hurdle in GEM-based chemotherapy for PC. Recent studies have shown that pyroptosis, a type of programmed death, plays a significant regulatory role in cancer development and therapy. In this study, we observed an increase in the expression of Caspase-1(CASP1)/Gasdermin-D (GSDMD) in PC and found that high expression of CASP1 and GSDMD was associated with poor overall survival (OS) and progression-free survival (PFS) of PC patients. Knockdown of either CASP1 or GSDMD resulted in the inhibition of cell viability and migration in PC cells. More importantly, the knockdown of CASP1 or GSDMD enhanced GEM-induced cell death in PC cells. Interestingly, subsequent investigations demonstrated that enzymatically active CASP1 promoted GEM-induced cell death in PC cells. The activation of CASP1 by the DPP8/DPP9 inhibitor (Val-boroPro, VbP) increased GEM-induced cell death by inducing pyroptosis. These findings suggest that inhibiting CASP1 to suppress its oncogenic effects or activating it to promote cell pyroptosis both enhance the sensitivity of PC cells to GEM therapy.

Overexpression of CASP1 triggers acute promyelocytic leukemia cell pyroptosis and differentiation.

Caspase-1 (CASP1)-mediated classical pyroptosis plays a key role in cancer development and management, however, the role of CASP1 and its regulation has not yet been documented for acute promyelocytic leukemia (APL). Here, we found that CASP1/GSDMD had lower expression in patients with APL and most other subtypes of primary de novo acute myeloid leukemia (AML) and was increased in all-trans-retinoic acid (ATRA)-treated APL cells. We showed that ATRA increases and activates CASP1 to trigger the pyroptosis and differentiation of APL cells. Mechanistically, ATRA could induce CASP1 expression via the IFNγ/STAT1 pathway in APL cells. In conclusion, ATRA-induced activation of CASP1 may serve as a suppressor in APL progression, as it triggers pyroptotic cell death and differentiation.

Higher 13-Gene-Estimated TMB Detected from Plasma ctDNA is Associated with Worse Outcome for T-Cell Lymphoma Patients.

Exome sequencing of in situ tumor samples reveals that mutated genes can predict the prognosis of patients with T-cell lymphoma (TCL). However, how tumor mutation burden (TMB) derived from circulating tumor DNA (ctDNA) may stratify TCL patients remains unclear.The plasma ctDNA of 79 newly diagnosed TCL patients from the clinical center is used for targeted exome sequencing, and the exome data of 4035 TCL patients from the Catalogue of Somatic Mutations in Cancer (COSMIC) database is obtained for comparison analysis.TCL patients with higher TMB, as evaluated with a panel of 120 genes (panel-TMB120), are associated with poor prognosis. More importantly, COX regression analysis identifies a subset of 13 genes in panel-TMB120, including AP3B1 (Adaptor related protein complex 3 subunit beta 1), ATM (Ataxia-telangiectasia mutated), BCL6 (B cell lymphoma 6), BRAF (B-Raf proto-oncogene, serine/threonine kinase), CDKN2B (Cyclin dependent kinase inhibitor 2B), EPCAM (Epithelial cell adhesion molecule), FBXO11 (F-box protein 11), JAK1 (Janus kinase 1), MDM2 (Murine double minute 2), NF1 (Neurofibromin 1), STAT5B (Signal transducer and activator of transcription 5B), STAT6 (Signal transducer and activator of transcription 6), and TET2 (Tet methylcytosine dioxygenase 2), which are significantly associated with prognosis. Specifically, higher TMB values calculated with these 13 genes (panel-TMB13) are able to significantly predict unfavorable prognosis for these patients. Together, panel-TMB13 and the International Prognostic Index (IPI) are used for risk stratification.Panel-TMB13 is identified, which can predict poor prognosis for TCL patients carrying higher panel-TMB13 scores and suggest that panel-TMB13 may be a potential biomarker for supplement risk stratification of TCL patients.

High expression of LOC541471, GDAP1, SOD1, and STK25 is associated with poor overall survival of patients with acute myeloid leukemia.

BACKGROUND: Acute myeloid leukemia (AML) is an aggressive heterogeneous hematological malignancy with remarkably heterogeneous outcomes. This study aimed to identify potential biomarkers for AML risk stratification via analysis of gene expression profiles. METHODS: RNA sequencing data from 167 adult AML patients in the Cancer Genome Atlas (TCGA) database were obtained for overall survival (OS) analysis, and 52 bone marrow (BM) samples from our clinical center were used for validation. Additionally, siRNA was used to investigate the role of prognostic genes in the apoptosis and proliferation of AML cells. RESULTS: Co-expression of 103 long non-coding RNAs (lncRNAs) and mRNAs in the red module that were positively correlated with European Leukemia Network (ELN) risk stratification and age was identified by weighted gene co-expression network analysis (WGCNA). After screening by uni- and multivariate Cox regression, Kaplan-Meier survival, and protein-protein interaction analysis, four genes including the lncRNA LOC541471, GDAP1, SOD1, and STK25 were incorporated into calculating a risk score from coefficients of the multivariate Cox regression model. Notably, GDAP1 expression was the greatest contributor to OS among the four genes. Interestingly, the risk score, ELN risk stratification, and age were independent prognostic factors for AML patients, and a nomogram model constructed with these factors could illustrate and personalize the 1-, 3-, and 5-year OS rates of AML patients. The calibration and time-dependent receiver operating characteristic curves (ROCs) suggested that the nomogram had a good predictive performance. Furthermore, new risk stratification was developed for AML patients based on the nomogram model. Importantly, knockdown of LOC541471, GDPA1, SOD1, or STK25 promoted apoptosis and inhibited the proliferation of THP-1 cells compared to controls. CONCLUSIONS: High expression of LOC541471, GDAP1, SOD1, and STK25 may be biomarkers for risk stratification of AML patients, which may provide novel insight into evaluating prognosis, monitoring progression, and designing combinational targeted therapies.

Targeting NRF2 uncovered an intrinsic susceptibility of acute myeloid leukemia cells to ferroptosis.

Drug resistance and poor treatment response are major obstacles to the effective treatment of acute myeloid leukemia (AML). A deeper understanding of the mechanisms regulating drug resistance and response genes in AML is therefore urgently needed. Our previous research has highlighted the important role of nuclear factor E2-related factor 2 (NRF2) in AML, where it plays a critical role in detoxifying reactive oxygen species and influencing sensitivity to chemotherapy. In this study, we identify a core set of direct NRF2 targets that are involved in ferroptosis, a novel form of cell death. Of particular interest, we find that glutathione peroxidase 4 (GPX4) is a key ferroptosis gene that is consistently upregulated in AML, and high expression of GPX4 is associated with poor prognosis for AML patients. Importantly, simultaneous inhibition of NRF2 with ML385 and GPX4 with FIN56 or RSL3 synergistically targets AML cells, triggering ferroptosis. Treatment with ML385 + FIN56/RSL3 resulted in a marked reduction in NRF2 and GPX4 expression. Furthermore, NRF2 knockdown enhanced the sensitivity of AML cells to the ferroptosis inducers. Taken together, our results suggest that combination therapy targeting both NRF2 and GPX4 may represent a promising approach for the treatment of AML.

Camptothecin induces apoptosis in cancer cells via microRNA-125b-mediated mitochondrial pathways.

Camptothecin (CPT) is an effective chemotherapeutic agent for treatment of patients with cancer. The mechanisms underlying CPT-mediated responses in cancer cells are not fully understood. MicroRNA (miRNA) play important roles in tumorigenesis and drug sensitivity. However, the interaction between camptothecin and miRNA has not been previously explored. In this study, we verified that miR-125b was down-regulated in CPT-induced apoptosis in cancer cells and that ectopic expression of miR-125b partially restored cell viability and inhibited cell apoptosis that was induced by CPT. In addition, we demonstrated that CPT induced apoptosis in cancer cells by miR-125b-mediated mitochondrial pathways via targeting to the 3'-untranslated (UTR) regions of Bak1, Mcl1, and p53. A significant increase in Bak1, Mcl1, and p53 protein levels was detected in response to the treatments of CPT. It is noteworthy that the expression levels of Bak1, Mcl1, and p53 increased in a time-dependent manner and negatively correlated with miR-125b expression. It is noteworthy that we revealed that miR-125b directly targeted the 3'UTR regions of multiple genes in a CPT-induced mitochondrial pathway. In addition, most targets of miR-125b were proapoptotic genes, whereas some of the targets were antiapoptotic genes. We hypothesized that miR-125b may mediate the activity of chemotherapeutic agents to induce apoptosis by regulating multiple targets. This is the first report to show that camptothecin induces cancer cell apoptosis via miRNA-mediated mitochondrial pathways. The results suggest that suppression of miR-125b may be a novel approach for the treatment of cancer.

miR-125b, a target of CDX2, regulates cell differentiation through repression of the core binding factor in hematopoietic malignancies.

MicroRNA-125b (miR-125b), a small noncoding RNA molecule, has been found to be deregulated and functions as an oncogene in many cancers including hematopoietic malignancies. However, the mechanisms accounting for miR-125b dysregulation remain to be elucidated. The present study aims to identify the factors that might contribute to up-regulation of miR-125b in human hematopoietic malignancies and its downstream targets for lineage-specific differentiation. We at first reported that CDX2, a homeobox transcription factor, binds to promoter regions of the miR-125b gene and activates transcriptional regulation of miR-125b in malignant myeloid cells. We further revealed that increasing levels of CDX2 in malignant myeloid cells activate miR-125b expression, which in turn inhibits core binding factor ß (CBFß) translation, thereby counteracting myeloid cell differentiation, at least for granulocytic lineage, and promoting leukemogenesis. Interestingly, we found that this novel pathway including CDX2, miR-125b, and CBFß was mediated by undergoing all-trans-retinoic acid induction. Once differentiation ensues with all-trans-retinoic acid treatment, CDX2 activity decreases, leading to a reduction in miR-125b transcription and up-regulation of CBFß in myeloid cells and in patients. The study provides a new mechanism that contributes to hematopoietic malignancies, which could involve deregulation of miR-125b and its up- and downstream factors. As altered expression of miRNAs has been reported in a wide range of malignancies, delineating the underlying molecular mechanisms of aberrant miRNA expression and characterizing the upstream and downstream factors will help to understand important steps in the pathogenesis of these afflictions.