SPARC silencing inhibits the growth of acute myeloid leukemia transformed from myelodysplastic syndrome via induction of cell cycle arrest and apoptosis

BAALC gene expression tells a serious patient outcome tale in NPM1-wild type/FLT3-ITD negative cytogenetically normal-acute myeloid leukemia in adults

Acute myeloid leukemia with normal cytogenetics (CN-AML) is the largest group of AML patients which is associated with a variegated patient outcome. Multiple molecular markers have been used to risk-stratify these patients. Estimation of expression of BAALC gene (Brain and Acute Leukemia, Cytoplasmic) mRNA level is one of the predictive markers which has been identified in multiple studies. In this study, we examined the clinical and prognostic value of BAALC gene expression in 149 adult CN-AML patients. We also utilized multi-omics databases to ascertain the association of BAALC gene expression with comprehensive molecular and clinicopathologic features in AML. BAALC overexpression was associated with CD34 positivity on leukemic blasts (p = 0.0026) and the absence of NPM1 gene mutation (p < 0.0001), presence of RUNX1 gene mutation (p < 0.001) and poor patient outcomes, particularly in NPM1-wild type/FLT3-ITD negative adult CN-AML patients. Additionally, BAALC expression was associated with the alteration of methylation of its promoter. Further, pathway analysis revealed that BAALC expression is correlated with MYC targets and Ras signalling. We conclude that high BAALC expression associates with poor patient outcome in NPM1-wild type/FLT3-ITD negative adult CN-AML patients.

CBFB-MYH11 Fusion Sequesters RUNX1 in Cytoplasm to Prevent DNMT3A Recruitment to Target Genes in AML

A growing number of human diseases have been found to be associated with aberrant DNA methylation, including cancer. Mutations targeting genes encoding DNA methyltransferase (DNMT), TET family of DNA demethylases, and isocitrate dehydrogenase (IDH1, IDH2) that produce TET inhibitory metabolite, 2-hyoxyglutarate (2-HG), are found in more than half of acute myeloid leukemia (AML). To gain new insights into the regulation of DNA de/methylation and consequence of its alteration in cancer development, we searched for genes which are mutated in a manner that is linked with gene mutations involved in DNA de/methylation in multiple cancer types. We found that recurrent CBFB-MYH11 fusions, which result in the expression of fusion protein comprising core-binding factor β (CBFB) and myosin heavy chain 11 (MYH11) and are found in 6∼8% of AML patients, occur mutually exclusively with DNMT3A mutations. Tumors bearing CBFB-MYH11 fusion show DNA hypomethylation patterns similar to those with loss-of-function mutation of DNMT3A. Expression of CBFB-MYH11 fusion or inhibition of DNMT3A similarly impairs the methylation and expression of target genes of Runt related transcription factor 1 (RUNX1), a functional partner of CBFB. We demonstrate that RUNX1 directly interacts with DNMT3A and that CBFB-MYH11 fusion protein sequesters RUNX1 in the cytoplasm, thereby preventing RUNX1 from interacting with and recruiting DNMT3A to its target genes. Our results identify a novel regulation of DNA methylation and provide a molecular basis how CBFB-MYH11 fusion contributes to leukemogenesis.

iTRAQ-based quantitative protein expression profiling of biomarkers in childhood B-cell and T-cell acute lymphoblastic leukemia

Purpose

This study screened serum proteins to identify potential biomarkers for childhood B-cell and T-cell acute lymphoblastic leukemia (ALL).

Patients and methods

Serum collected from 20 newly diagnosed B-cell ALL, 20 T-cell ALL and 20 healthy children. The peptides from these samples were subjected to iTRAQ. Differentially expressed proteins (DEPs) were further validated by ELISA in 24 B-ALL, 24 T-ALL, and 24 healthy children.

Results

Bioinformatics analysis revealed several pathways, including atherosclerosis signaling, interleukin signaling and production in macrophages and clathrin-mediated endocytosis signaling, that were closely related to childhood T-cell ALL. Furthermore, four selected proteins, namely LRG1, S100A8, SPARC and sL-selectin, were verified by ELISA. These results were consistent with the results of the proteomics analysis.

Conclusion

Serum S100A8 may serve as new diagnostic biomarkers in childhood B-cell ALL and T-cell ALL.

Altered CSF Proteomic Profiling of Paediatric Acute Lymphocytic Leukemia Patients with CNS Infiltration

Background

For childhood acute lymphocytic leukemia (ALL), central nervous system leukemia (CNSL) is still the main reason of treatment failure. Changes of cerebrospinal fluid (CSF) proteome are deemed to occur after intrathecal chemotherapy.

Objective

To find critical CSF biomarkers, which could be utilized to increase diagnostic and prognostic accuracy of CNSL.

Methods

We performed proteomic profiling of CSF before and after the treatment of six sporadic paediatric patients diagnosed as ALL with central nervous system (CNS) involvement. CSF samples were properly processed and analyzed through the use of label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Results

Among identified 428 unique proteins in all CSF samples, we quantified 10 altered proteins with diverse biological functions after induction chemotherapy.

Conclusions

The levels of those 10 proteins change during the treatment of CNSL. Some of the proteins are likely to play a vital biological role as biomarkers for the development of ALL. In addition, our results indicated the feasible and reproducible utility of CSF for diagnosis and prognosis of patients with CNSL.

Smoc2 potentiates proliferation of hepatocellular carcinoma cells via promotion of cell cycle progression

AIM

To determine the influence of Smoc2 on hepatocellular carcinoma (HCC) cell proliferation and to find a possible new therapeutic target for preventing HCC progression.

METHODS

We detected expression of Smoc2 in HCC tissues and corresponding non-tumor liver (CNL) tissues using PCR, western blot, and immunohistochemistry methods. Subsequently, we down-regulated and up-regulated Smoc2 expression using siRNA and lentivirus transfection assay, respectively. Then, we identified the effect of Smoc2 on cell proliferation and cell cycle using CCK-8 and flow cytometry, respectively. The common cell growth signaling influenced by Smoc2 was detected by western blot assay.

RESULTS

The expression of Smoc2 was significantly higher in HCC tissues compared with CNL tissues. Overexpression of Smoc2 promoted HCC cell proliferation and cell cycle progression. Down-regulation of Smoc2 led to inhibition of cell proliferation and cell cycle progression. Smoc2 had positive effect on ERK and AKT signaling.

CONCLUSION

Smoc2 promotes the proliferation of HCC cells through accelerating cell cycle progression and might act as an anti-cancer therapeutic target in the future.

Gene expression profiling in myelodysplastic syndrome after SPARC overexpression associated with Ara-C

Secreted protein acidic and rich in cysteine (SPARC) is involved in many biological processes, including erythropoiesis and cell proliferation. However, the role of SPARC in myelodysplastic syndrome (MDS) remains to be elucidated. Pyrimidine analogue cytosine arabinoside (Ara-C) is among the most effective agents used in the treatment of acute leukemia. The aim of the present study was to determine whether the chemotherapeutic activity of Ara-C was enhanced by the overexpression of SPARC. DNA microarray technology and RNA sequencing were employed to examine differential gene expression in the apoptosis signaling pathway after gene change occurred in cells following drug treatment. The results showed that upregulation of the expression of SPARC induced SKM-1 cell death and inhibited proliferation. Additionally, the apoptotic rate of SPARC overexpression combined with Ara-C increased significantly. Transcription factors CPBP and ZNF333 regulated the 69 genes and long non-coding RNA (lncRNA). Moreover, the mRNA and protein expression of apoptosis-related genes in the DNA microarray results were increased. These results suggest that SPARC expression changes with Ara-C, revealing a possible application in the treatment of MDS.

SPARC ectopic overexpression inhibits growth and promotes programmed cell death in acute myeloid leukemia transformed from myelodysplastic syndrome cells, alone and in combination with Ara-C treatment

Secreted protein acidic and rich in cysteine (SPARC) has a complex and pleiotropic biological role in cell life during disease. The role of SPARC in myelodysplastic syndrome (MDS) is not yet fully understood. In the present study, we investigated the role of SPARC protein overproduction in the proliferation and apoptosis of SKM-1 cells, an acute myeloid leukemia cell line transformed from MDS. SKM-1 cells were infected with the pGC-GV-SPARC vector. The cells were then assessed for proliferation and cell death following treatment with low-dose cytosine arabinoside (Ara‑C). The microarray analysis results revealed that samples from SPARC‑overexpressed cells compared to SPARC protein, in SKM-1 cells led to proliferation inhibition and promoted programmed cell death and these effects were greater when treated with Ara-C. The mRNA and protein expression levels of SPARC were detected by SPARC overexpression in cells treated with Ara-C resulting in a significant upregulation of the mixed lineage kinase domain-like (MLKL) gene expression and five other genes. The results showed that the necrotic signaling pathway may play a role when the two conditions were combined via the upregulation of the MLKL protein. MLKL upregulation in SPARC overexpressed cells treated with Ara-C, indicates necrosis as a possible cell death process for the SKM-1 cells under these stringent conditions.

Comparison of TP53 mutations screening by functional assay of separated allele in yeast and next-generation sequencing in myelodysplastic syndromes

TP53 mutations are major prognostic factors in many hematological malignancies including acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). Next-generation sequencing (NGS) has improved the detection of such mutations by identifying small mutated clones but functional method like FASAY (functional assay of separated allele in yeast) may prove interesting. We compared the detection of TP53 mutations by FASAY and NGS in 91 patients with AML or MDS. By FASAY, 91% of assays were evaluable and 47 patients (57%) had a functional and 36 (43%) a non-functional p53 protein. FASAY could not conclude in 8 cases (9%), mainly because of poor RNA quality. No TP53 mutation was found using NGS in 50 cases (55%), and at least one mutation was detected in 41 cases (45%). The p53 status was concordant between FASAY and NGS in 95% (79/83) of cases. The four discordances included mutations detected by FASAY only in two cases, and by NGS only in two cases. Mutations not detected by NGS consisted of insertions in intronic regions, which were not analyzed by this assay. Mutations not detected by FASAY were mutations for which the percentage of mutated allele was less than 10%, including one mutation reported as non-deleterious in the IARC database. Overall, our data suggest that FASAY is an effective and reliable method to detect TP53 mutations in AML and MDS, which allows the assessment of the protein functionality, contrary to a sequencing approach.

SPAG6 silencing inhibits the growth of the malignant myeloid cell lines SKM-1 and K562 via activating p53 and caspase activation-dependent apoptosis

SPAG6, which is a novel cancer-testis antigen, is overexpressed in myeloid malignancies. Previously, SPAG6 was found in UPD (uniparental disomy) region of myeloid cell DNA from MDS patients and reported that SPAG6 may be a predictive marker of minimal residual disease in pediatric acute myeloid, but the biological role of SPAG6 in myeloid malignancies remains unclear. The present study was undertaken to determine the expression and functional significance of SPAG6 in malignant myeloid hematologic cell lines. A short hairpin RNA (shRNA) targeting SPAG6 was designed that could specifically inhibit SPAG6 expression at the mRNA and protein levels when introduced into the malignant myeloid hematologic cell lines SKM-1 and K562. The results from flow cytometry and CCK-8 assays showed that SPAG6 silencing inhibited the proliferation of SKM-1/K562 by inducing apoptosis. Furthermore, SPAG6 silencing resulted in activation of caspase-3, -9 and -8 and upregulated the mRNA and protein expression of p53 and PTEN. Then, we subcutaneously inoculated the monoclonal cells into NOD/SCID mice to establish xenograft models, and we found that the SPAG6-shRNA lentivirus dramatically inhibited tumor growth and increased apoptosis in vivo. These findings demonstrate that SPAG6 might have a role in malignant myeloid hematologic cell proliferation and apoptosis by regulating caspase proteins and p53, suggesting that SPAG6 may be a potential therapeutic target.