Super-enhancer-associated EEPD1 facilitates EMT-mediated metastasis by regulating the PI3K/AKT/mTOR pathway in gastric cancer.

This study focused on exploring the mechanism of the EMT mediated by endonuclease/exonuclease/phosphatase family domain-containing 1 (EEPD1) in gastric cancer metastasis. Through bioinformatics analysis, EEPD1 was found to be a target gene of super enhancers (SEs) in gastric cancer tissues. EEPD1 exhibited higher expression levels in tumor tissues and was associated with poor prognosis. In vitro and in vivo studies have demonstrated that silencing EEPD1 significantly suppressed the proliferation, metastasis, and invasion of gastric cancer cells. Furthermore, EEPD1 knockdown was involved in the regulation of the EMT and suppressed expression of AKT, a downstream component of the PI3K pathway, leading to a reduction in the phosphorylation levels of AKT and its downstream molecule, mTOR. These results showed the potential of EEPD1 as a prognostic indicator and therapeutic target in gastric cancer.

SNHG16 lncRNAs are overexpressed and may be oncogenic in human gastric cancer by regulating cell cycle progression.

The small nucleolar RNA host gene 16 (SNHG16) has recently been shown to be a putative oncogene in gastric cancer (GC) and other cancer types, but how its four lncRNA variants are expressed in any physiological and pathological situation remains unknown. To investigate the expression and function of the four lncRNA variants of SNHG16, mainly the variant 1, in GC, we performed quantitative PCR to determine the RNA levels of the four variants in 60 GC tissue samples and several cell lines. We also studied how knocking down of SNHG16 with siRNA affected proliferation, apoptosis, cell cycle progression, as well as migration and invasion of GC cells. Our results showed that variants 1 and 4 were overexpressed in GC tissues compared with adjacent uninvolved tissues. Knockdown of the four variants, mainly the variant 1, enhanced apoptosis and inhibited cell cycle progression of a GC cell line by arresting the cells at the G1 phase. These cellular effects were associated not only with decreased protein levels of c-Myc, PCNA, cyclins D1, E1, A2 and B, as well as CDKs 2 and 6, but also with increased protein levels of the p21, p27 and p53. Knockdown of total SNHG16 lncRNAs also inhibited invasion and migration of the GC cells in vitro. These results collectively suggest that SNHG16 may be oncogenic in GC by regulating cell cycle progression and may serve as a GC biomarker.

Simvastatin Overcomes Resistance to Tyrosine Kinase Inhibitors in Patient-derived, Oncogene-driven Lung Adenocarcinoma Models.

There is an unmet clinical need to develop novel strategies to overcome resistance to tyrosine kinase inhibitors (TKI) in patients with oncogene-driven lung adenocarcinoma (LUAD). The objective of this study was to determine whether simvastatin could overcome TKI resistance using the in vitro and in vivo LUAD models. Human LUAD cell lines, tumor cells, and patient-derived xenograft (PDX) models from TKI-resistant LUAD were treated with simvastatin, either alone or in combination with a matched TKI. Tumor growth inhibition was measured by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and expression of molecular targets was assessed by immunoblots. Tumors were assessed by histopathology, IHC stain, immunoblots, and RNA sequencing. We found that simvastatin had a potent antitumor effect in tested LUAD cell lines and PDX tumors, regardless of tumor genotypes. Simvastatin and TKI combination did not have antagonistic cytotoxicity in these LUAD models. In an osimertinib-resistant LUAD PDX model, simvastatin and osimertinib combination resulted in a greater reduction in tumor volume than simvastatin alone (P < 0.001). Immunoblots and IHC stain also confirmed that simvastatin inhibited TKI targets. In addition to inhibiting 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase, RNA sequencing and Western blots identified the proliferation, migration, and invasion-related genes (such as PI3K/Akt/mTOR, YAP/TAZ, focal adhesion, extracellular matrix receptor), proteasome-related genes, and integrin (α3ß1, αvß3) signaling pathways as the significantly downregulated targets in these PDX tumors treated with simvastatin and a TKI. The addition of simvastatin is a safe approach to overcome acquired resistance to TKIs in several oncogene-driven LUAD models, which deserve further investigation.

Dynamic evaluation of blood immune cells predictive of response to immune checkpoint inhibitors in NSCLC by multicolor spectrum flow cytometry.

Introduction: Immune checkpoint inhibitors (ICIs) only benefit a subset of cancer patients, underlining the need for predictive biomarkers for patient selection. Given the limitations of tumor tissue availability, flow cytometry of peripheral blood mononuclear cells (PBMCs) is considered a noninvasive method for immune monitoring. This study explores the use of spectrum flow cytometry, which allows a more comprehensive analysis of a greater number of markers using fewer immune cells, to identify potential blood immune biomarkers and monitor ICI treatment in non-small-cell lung cancer (NSCLC) patients. Methods: PBMCs were collected from 14 non-small-cell lung cancer (NSCLC) patients before and after ICI treatment and 4 healthy human donors. Using spectrum flow cytometry, 24 immune cell markers were simultaneously monitored using only 1 million PBMCs. The results were also compared with those from clinical flow cytometry and bulk RNA sequencing analysis. Results: Our findings showed that the measurement of CD4+ and CD8+ T cells by spectrum flow cytometry matched well with those by clinical flow cytometry (Pearson R ranging from 0.75 to 0.95) and bulk RNA sequencing analysis (R=0.80, P=1.3 x 10-4). A lower frequency of CD4+ central memory cells before treatment was associated with a longer median progression-free survival (PFS) [Not reached (NR) vs. 5 months; hazard ratio (HR)=8.1, 95% confidence interval (CI) 1.5-42, P=0.01]. A higher frequency of CD4-CD8- double-negative (DN) T cells was associated with a longer PFS (NR vs. 4.45 months; HR=11.1, 95% CI 2.2-55.0, P=0.003). ICIs significantly changed the frequency of cytotoxic CD8+PD1+ T cells, DN T cells, CD16+CD56dim and CD16+CD56- natural killer (NK) cells, and CD14+HLDRhigh and CD11c+HLADR + monocytes. Of these immune cell subtypes, an increase in the frequency of CD16+CD56dim NK cells and CD14+HLADRhigh monocytes after treatment compared to before treatment were associated with a longer PFS (NR vs. 5 months, HR=5.4, 95% CI 1.1-25.7, P=0.03; 7.8 vs. 3.8 months, HR=5.7, 95% CI 169 1.0-31.7, P=0.04), respectively. Conclusion: Our preliminary findings suggest that the use of multicolor spectrum flow cytometry helps identify potential blood immune biomarkers for ICI treatment, which warrants further validation.

New strategy for clinical etiologic diagnosis of acute ischemic stroke and blood biomarker discovery based on machine learning.

Acute ischemic stroke (AIS) is a syndrome characterized by high morbidity, prevalence, mortality, recurrence and disability. The longer the delay before proper treatment of a stroke, the greater the likelihood of brain damage and disability. Computed tomography and nuclear magnetic resonance are the primary choices for fast diagnosis of AIS in the early stage, which can provide certain information about infarction location and degree, and even the vascular distribution of lesions responsible for strokes. However, this is quite difficult to achieve in small clinics or at-home diagnoses. Hematology tests could quickly obtain a large number of pathology-related indicators, and offer an effective method for rapid AIS diagnosis when combined with the machine learning technique. To explore a reliable, predictable method for early clinical etiologic diagnosis of AIS, a retrospective study was deployed on 456 AIS patients at the early stage and 28 reference subjects without the symptoms of AIS, by means of the selected significant traits amongst 64 clinical and blood traits in conjunction with powerful machine learning strategies. Five representative biomarkers were closely related to cardioembolic (CE), 22 to large artery atherosclerosis (LAA), and 15 to small vessel occlusion (SVO) strokes, respectively. With these biomarkers, different etiologic subtypes of stroke patients were determined with high accuracy of >0.73, sensitivity of >0.73, and specificity of >0.70, which was comparable to the accuracy obtained in the emergency department by clinical diagnosis. The proposed method may offer an alternative strategy for the etiologic diagnosis of AIS at the early stage when integrating significant blood traits into machine learning.

Roles of circRNAs in hematological malignancies.

As one of the leading causes of death, hematologic malignancies are associated with an ever-increasing incidence, and drug resistance and relapse of patients after treatment represent clinical challenges. Therefore, there are pressing demands to uncover biomarkers to indicate the development, progression, and therapeutic targets for hematologic malignancies. Circular RNAs (circRNAs) are covalently closed circular-single-stranded RNAs whose biosynthesis is regulated by various factors and is widely-expressed and evolutionarily conserved in many organisms and expressed in a tissue-/cell-specific manner. Recent reports have indicated that circRNAs plays an essential role in the progression of hematological malignancies. However, circRNAs are difficult to detect with low abundance using conventional techniques. We need to learn more information about their features to develop new detection methods. Herein, we sought to retrospect the current knowledge about the characteristics of circRNAs and summarized research on circRNAs in hematological malignancies to explore a potential direction.

Nrf2 Overexpression Decreases Vincristine Chemotherapy Sensitivity Through the PI3K-AKT Pathway in Adult B-Cell Acute Lymphoblastic Leukemia.

Uncontrolled proliferation is an important cancer cell biomarker, which plays a critical role in carcinogenesis, progression and development of resistance to chemotherapy. An improved understanding of novel genes modulating cancer cell proliferation and mechanism will help develop new therapeutic strategies. The nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor, decreases apoptosis when its expression is upregulated. However, the relationship between Nrf2 and Vincristine (VCR) chemotherapy resistance in B-cell acute lymphoblastic leukemia (B-ALL) is not yet established. Our results showed that Nrf2 levels could sufficiently modulate the sensitivity of B-ALL cells to VCRby regulating an apoptotic protein, i.e., the Bcl-2 agonist of cell death (BAD). Chemotherapeutic agents used for the treatment of B-ALL induced Nrf2 overactivation and PI3K-AKT pathway activation in the cells, independent of the resistance to chemotherapy; thus, a potential resistance loop during treatment for B-ALL with a drug combination is established. Therefore, B-ALL patients with a high expression of Nrf2 might mean induction chemotherapy with VCR effective little.

Interleukin-35 promotes Breg expansion and interleukin-10 production in CD19+ B cells in patients with ankylosing spondylitis.

OBJECTIVE: IL-35 is a potent immunosuppressive and anti-inflammatory cytokine, consisting of a p35 subunit and an Epstein-Barr virus-induced gene 3 (EBI3) subunit, which suppresses CD4+ effector T cell proliferation and promotes regulatory T cell (Treg) expansion. However, the effects of IL-35 on regulatory B cells (Bregs) in ankylosing spondylitis (AS) have not been explored. The present study aimed (i) to measure serum IL-35 levels and the percentages of Bregs in the peripheral blood of patients with AS and (ii) to explore their relationships in the pathogenesis of AS. METHODS: A total of 77 patients with AS (AS group), including 47 inactive AS and 30 active AS cases, and 59 healthy controls (HCs) were enrolled into this study. The serum levels of IL-35 and IL-10 were detected by ELISA, and the mRNA levels of p35 and EBI3 were measured by RT-qPCR. The percentages of CD19+CD24hiCD38hi and CD19+CD24hiCD27+ Bregs and IL-35 receptor (IL-12Rß2, IL-27Rα and gp130), IL-10, p-STAT1, p-STAT3, and p-STAT4 in CD19+ B cells were detected by flow cytometry. The correlations between IL-35 levels and percentages of Bregs were analyzed by determining Pearson's correlation coefficient. The effect of IL-35 on Bregs was determined by mix-culture of recombinant (r) IL-35 with peripheral blood mononuclear cells (PBMCs). RESULTS: The serum IL-35 and IL-10 levels, p35 and EBI3 mRNA levels, and the percentages of CD19+CD24hiCD38hi and CD19+CD24hiCD27+ Bregs were significantly lower in AS patients than those in HCs. In addition, the percentages of CD19+CD24hiCD38hi and CD19+CD24hiCD27+ Bregs in active AS patients were significantly lower than those in inactive AS patients. The serum IL-35 levels were positively correlated with the percentages of CD19+CD24hiCD38hi and CD19+CD24hiCD27+ Bregs in AS patients. IL-12Rß2 and IL-27Rα, but not gp130 subunit, were expressed in CD19+ B cells in AS patients. RIL-35 could effectively promote CD19+CD24hiCD38hi Breg expansion and IL-10 production. Meanwhile, rIL-35 also promoted the expression of IL-12Rß2 and IL-27Rα and the phosphorylation of STAT1 and STAT3 in CD19+ B cells. CONCLUSION: These results demonstrated that reduced IL-35 production may be associated with Bregs defects in AS patients. RIL-35 induced the proliferation of CD19+CD24hiCD38hi Bregs and IL-10 production, suggesting that IL-35 may serve as a reference for further investigation to develop novel treatments for AS. Key Points • Our study investigated the effects of IL-35 on Bregs in AS patients. • We found the serum IL-35, IL-10 levels, and the percentages of CD19+CD24hiCD38hi and CD19+CD24hiCD27+ Bregs were significantly lower in AS patients. • The serum IL-35 levels were positively correlated with the percentages of CD19+CD24hiCD38hi and CD19+CD24hiCD27+ Bregs in AS patients. • Recombinant IL-35 could effectively promote CD19+CD24hiCD38hi Breg expansion and IL-10 production.

[Effect of Down-Regulation of ANRIL on Proliferation and Apoptosis of Kasumi-1 Cells and Its Potential Mechanism].

OBJECTIVE: To investigate the down-regulation of ANRIL (Antisense non-coding RNA in the INK4 Locus) effects on proliferation and apoptosis of Kasumi-1 cells and its related molecular mechanism. METHODS: Recombinant lentivirus was used to construct ANRIL down-regulation Kasumi-1 cells (sh-ANRIL group) and its control cells (sh-NC group). A fluorescence microscope was used to observe the transfection efficiency, RT-qPCR was used to detect knockdown efficiency and ANRIL expression in PBMCs and MBMCs of patients with acute myeloid leukemia (AML). Proliferation and apoptosis of Kasumi-1 cells were assayed by CCK-8 method and flow cytometry. Western blot was employed to detect the expression of PI3K, AKT, p-AKT, and relevant protein after down-regulation of ANRIL in Kasumi-1 cells. RESULTS: ANRIL overexpressed significantly in PBMCs and MBMCs of patients with AML, the transfection efficiency of recombinant lentivirus carrying sh-ANRIL and sh-NC on Kasumi-1 cells exceeded 90%, and the knockdown efficiency was 70%. When DNR was administrated for 24, 48, and 72 hours, the cell inhibition rate of the sh-ANRIL group was (47.40±1.49)%, (69.11±0.51)% and (91.82±1.10)%, which were significantly higher than those of the sh-NC group, respectively (P<0.05). The apoptotic rate in the sh-ANRIL group was (10.29±0.58)%, which was significantly higher than (5.42±0.67)% of the sh-NC group (P<0.01). After DNR treatment for 24 hours, the apoptotic rate of the sh-ANRIL group was (54.41±1.69)%, which was significantly higher than (38.28±1.42)% of sh-NC group (P<0.001). Western blot revealed that the protein levels of PI3K, p-AKT, PCNA, and BCL-2 in the sh-ANRIL group were reduced significantly than those in the sh-NC group, while the BAX protein expression increased. CONCLUSION: ANRIL may affect the proliferation and apoptosis of Kasumi-1 cells through PI3K/AKT signaling pathway. ANRIL is a potential therapeutic target for AML.

High integrin α3 expression is associated with poor prognosis in patients with non-small cell lung cancer.

BACKGROUND: We previously showed that α3ß1 integrin is a novel cancer biomarker and drug target in non-small cell lung cancer (NSCLC). This study characterized the integrin α3 (ITGA3) expression on patient specimens. METHODS: Tissue microarrays (TMAs) were prepared from archival tissue blocks containing 161 patients, which included 91 adenocarcinoma (LUAD), 46 squamous carcinomas (LUSC), and 24 other histology types. TMA sections were stained and scored for ITGA3 expression by immunohistochemistry (IHC). Kaplan-Meier curves and log-rank tests were used to compare overall survival (OS) between IHC score groups. Propensity-score-weighted Kaplan-Meier curves and weighted Cox models were used to adjust for covariate imbalance between IHC score groups. Logistic regression was used to determine ITGA3 transcriptome expression in NSCLC in The Cancer Genome Atlas (TCGA). RESULTS: ITGA3 IHC expression (1+ to 3+) was detected in 107/161 (66.5%) of the NSCLC samples, and was associated with poor prognosis at the edge of significance (HR =1.30, 95% CI: 0.99-1.71, P=0.056), but significant (P<0.05) in subgroups of female patients, smokers and tumors with grade I and II differentiation using propensity-score-weighted survival analysis after adjusting for confounders. Multivariate survival analysis based on multiple imputation for missing variables showed ITGA3 expression, old age and metastasis were associated with poor prognosis (P<0.05). ITGA3 IHC expression was associated with poor prognosis in LUSC (HR =2.27, P<0.05) but not in LUAD (HR =1.49, P=0.16). Median ITGA3 expression was significantly higher in LUAD than LUSC (P<0.0001) in the TCGA transcriptome datasets. Using a higher cutoff than LUSC (70.6 vs. 19.5 FPKM), high ITGA3 RNA expression was also associated with poor prognosis in LUAD (P=0.023). ITGA3 interacted with key genes regulating epithelial to mesenchymal transition, angiogenesis, invasion and metastasis in both LUAD and LUSC. CONCLUSIONS: High ITGA3 IHC expression was associated with poor prognosis in NSCLC patients. Further study is warranted for targeting α3ß1 integrin in NSCLC.

LncRNA SNHG16 promotes epithelial- mesenchymal transition via down-regulation of DKK3 in gastric cancer.

Recent studies have shown that long noncoding RNAs (lncRNAs) have profound impacts on cancer development. In our previous study, we have confirmed that lncRNA small nucleolar RNA host gene 16 (SNHG16) is associated with poor prognosis and malignant phenotype of gastric cancer (GC). However, the biological function of lncRNA SNHG16 is still unclear. Here, we aimed to investigate the mechanisms underlying the roles of SNHG16 in GC. In this work, SNHG16 knockdown could inhibit epithelial-mesenchymal transition (EMT) and invasion of GC cells. Moreover, our results revealed that SNHG16 could promote EMT via down-regulation of Dickkopf WNT signaling pathway inhibitor 3 (DKK3) in GC cells. In addition, SNHG16 was found to be upregulated whereas DKK3 was downregulated in tumor tissues compared with adjacent normal tissues. It showed that the expressions of SNHG16 and DKK3 were negatively correlated in clinical GC tissues.All these results suggested that SNHG16 promotes GC progression via regulation of DKK3 directly or indirectly. SNHG16 might be used as a putative biomarker for metastatic prediction in GC patients.

Correction to: High-affinity peptide ligand LXY30 for targeting α3ß1 integrin in non-small cell lung cancer.

The original article [1] contains an error in Fig. 2 whereby Fig. 2D has mistakenly been omitted. Fig. 2 can be viewed in its entirety - including Fig. 2D - in this Correction article.

High-affinity peptide ligand LXY30 for targeting α3ß1 integrin in non-small cell lung cancer.

BACKGROUND: α3ß1 integrin is a promising cancer biomarker and drug target. We previously identified a 9-amino-acid cyclic peptide LXY30 for detecting α3ß1 integrin on the surface of live tumor cells. This study was undertaken to characterize LXY30 in the detection, cellular function, imaging, and targeted delivery of in vitro and in vivo non-small cell lung cancer (NSCLC) models. METHODS: The whole-cell binding assay was performed by incubating NSCLC cells, extracellular vesicles (EVs), and peripheral blood mononuclear cells (PBMCs) with TentaGel resin beads coated with LXY30. In this study, we defined the nanosize EVs as exosomes, which were characterized by flow cytometry, transmission electron microscopy, dynamic light scattering, and Western blots. The function of LXY30 was determined by modulating the epidermal growth factor receptor (EGFR) signaling pathway by growth inhibition and Western blots. For in vivo biodistribution, mice bearing subcutaneous and intracranial NSCLC xenograft tumors were administrated intraveneously with LXY30-biotin/streptavidin-Cy5.5 complex and then analyzed for in vivo and ex vivo optical imaging and histopathology. RESULTS: We showed that LXY30 specifically and sensitively detected α3ß1 integrin-expressing NSCLC cells and tumor-derived exosomes. Tumor DNA isolated from LXY30-enriched plasma exosomes might be used to detect driver oncogenic mutations in patients with metastatic NSCLC. LXY30 only enriches tumor cells but not neutrophils, macrophages, or monocytes in the malignant pleural effusion of NSCLC patients for detecting genomic alterations by next-generation sequencing. LXY30 detected increased α3ß1 integrin expression on the EGFR-mutant NSCLC cells with acquired resistance to erlotinib compared to parental erlotinib-sensitive EGFR-mutant NSCLC cells. We further showed that LXY30 modulated the EGFR signaling pathway independently from another peptide ligand LXW64 targeting αvß3 integrin in erlotinib-resistant, EGFR-mutant H1975 cells. Analysis of The Cancer Genome Atlas (TCGA) revealed high α3 integrin expression was associated with poor prognosis in lung squamous cell carcinoma. LXY30-biotin/streptavidin-Cy5.5 complex had higher uptakes in the subcutaneous and intracranial xenografts of various α3ß1 integrin-expressing lung adenocarcinoma and patient-derived lung squamous cell carcinoma xenografts while sparing the surrounding normal tissues. CONCLUSION: LXY30 is a promising peptide for the cancer diagnosis and in vivo targeted delivery of imaging agents and cancer drugs in NSCLC, independent of histology and tumor genotype.

Knockdown of long noncoding RNA GHET1 inhibits cell­cycle progression and invasion of gastric cancer cells.

GHET1 is an oncogenic long noncoding RNA (lncRNA) that promotes the proliferation and invasion of many malignant cell types. However, the function and underlying mechanisms of lncRNA GHET1 in gastric cancer are not fully understood. In this study, the expression of GHET1 was investigated in gastric cancer and it was determined whether GHET1 may potentially be used as a biomarker for the disease. The gastric cancer cell lines MGC­803 and AGS were transfected with GHET1­directed small interfering RNA (siRNA) and the changes in phenotype and cell­cycle­related molecules were assessed. The downregulation of GHET1 induced G0/G1­phase arrest in gastric cancer cells and inhibited their proliferation, migration, and invasion. DNA synthesis and the expression of proliferating cell nuclear antigen (PCNA) decreased, which was consistent with the results of the CCK­8 assay. The levels of specific cell­cycle regulators were determined and the expression and activities of positive cell­cycle regulators (cyclin D, CDK4, CDK6, cyclin E, CDK2) were reduced, whereas those of a negative regulator (P21) were increased in GHET1­knockdown cells. Taken together, the present findings show that the downregulation of GHET1 not only inhibits the migration and invasion of gastric cancer cells, but also inhibits their proliferation, at least in part by upregulating P21 expression and downregulating cyclin and CDK expression to inhibit the G0/G1 to S phase transition. The present findings may provide a potential therapeutic target for gastric cancer.

In vivo and in vitro effects of heme oxygenase-1 silencing on the survival of acute myelocytic leukemia-M2 cells.

The aim of this study was to investigate the in vivo and in vitro effects of targeted heme oxygenase-1 (HO-1) silencing on the proliferation and apoptosis of human acute myelocytic leukemia (AML)-M2 cells. Bone marrow mononuclear cells (BMMNCs) were infected by pRNAi-siHO-1-GFP. The viability of the BMMNCs was determined by cell counting kit-8 (CCK-8) assay following daunorubicin (DNR) treatment. The apoptotic rate was detected by flow cytometry. The expression levels of HO-1 and apoptosis-related genes were detected by quantitative polymerase chain reaction (qPCR) and western blot analysis. An AML-M2 xenograft mouse model was established. The tumor formation outcomes and survival were observed. The leukocyte and platelet counts and hemoglobin levels were monitored, and the copy numbers of AML1/ETO fusion gene were detected by qPCR. pRNAi-siHO-1-GFP silenced the expression of HO-1. DNR inhibited cell viability in a time- and dose-dependent manner. The survival rate of the cells was significantly reduced by infection with pRNAi-siHO-1-GFP. HO-1 expression in the BMMNCs infected with pRNAi-siHO-1-GFP was downregulated, whereas caspase-3, -8 and -9 expression was upregulated compared with that in control BMMNCs. Kasumi-1 cells were successfully inoculated into nude mice. The rats inoculated with pRNAi-siHO-1-GFP-transfected Kasumi-1 cells succumbed to tumors more slowly and survived longer than those inoculated with untransfected Kasumi-1 cells. Furthermore, the leukocyte and platelet counts and hemoglobin levels were higher and the copy numbers of AML1/ETO fusion gene were lower in the former group. HO-1 gene silencing may promote the apoptosis of human M2 leukemic cells by inhibiting a caspase-dependent apoptotic pathway. Targeted silencing of HO-1 is able to inhibit the proliferation and infiltration of leukemic cells in nude mice and thus prolong their survival. The findings provide valuable experimental evidence for the molecular targeted therapy of M2 leukemia.

Phenethyl isothiocyanate inhibits growth of human chronic myeloid leukemia K562 cells via reactive oxygen species generation and caspases.

Phenethyl isothiocyanate (PEITC), a potential cancer chemopreventive constituent of cruciferous vegetables, including watercress, has been reported to inhibit cancer cell growth by arresting the cell cycle and inducing apoptosis in various human cancer cell models. However, the role of PEITC in the inhibition of human chronic myeloid leukemia (CML) K562 cell growth and its underlying mechanisms have yet to be elucidated. In the present study, PEITC was found to induce cell death through the induction of reactive oxygen species (ROS) stress and oxidative damage. Heme oxygenase­1 (HO­1), which participates in the development of numerous tumors and the sensitivity of these tumors to chemotherapeutic drugs, plays a protective role by modulating oxidative injury. Therefore, the present study assessed the inhibitory effect of PEITC on K562 cells and whether HO­1 facilitated cell apoptosis and ROS generation. PEITC was found to suppress cell growth and cause apoptosis by promoting Fas and Fas ligand expression, increasing ROS generation and by the successive release of cytochrome c as well as the activation of caspase­9 and caspase­3. PEITC was also combined with the HO­1 inhibitor zinc protoporphyrin IX and the inducer hemin to assess whether HO­1 determines cell survival and ROS generation. The results of the present study suggest that PEITC may be a potential anti­tumor compound for CML therapy, and that HO­1 has a critical function in PEITC­induced apoptosis and ROS generation.

Potential crosstalk of Ca2+-ROS-dependent mechanism involved in apoptosis of Kasumi-1 cells mediated by heme oxygenase-1 small interfering RNA.

Acute myeloid leukemia (AML) requires new therapies on the molecular level. Downregulation of heme oxygenase-1 (HO-1) by gene silencing improves the sensitivity of tumor cells to chemotherapy drugs and promotes apoptosis. For the first time, we verified that endoplasmic reticulum and mitochondrial apoptotic pathways were activated by small interfering RNA that targeted-silenced the expression of HO-1 in AML-M2 Kasumi-1 cells. Ca2+ was prone to accumulation and reactive oxygen species were easily generated, while mitochondrial transmembrane potential was reduced. Thus, cytochrome c was released from mitochondria to the cytoplasm and caspases were activated for the following cascade to facilitate apoptosis.

Over-expression of heme oxygenase-1 in peripheral blood predicts the progression and relapse risk of chronic myeloid leukemia.

BACKGROUND: There are limited eligible clinical markers at present to monitor the progress of chronic myeloid leukemia (CML). Heme oxygenase-1 (HO-1), as one of the most important oxidation-regulating enzymes in vivo, suggests the onset and progression of cancer when highly expressed. Furthermore, HO-1 level is related with the occurrence and development of hematological diseases. But the relationship between HO-1 expression and progression/relapse of CML has seldom been studied hitherto. This study aimed to investigate the relationship between them to find out a new molecular marker for prediction. METHODS: A total of 60 peripheral blood and bone marrow (BM) samples from 25 CML patients in different phases were collected respectively to detect the expressions of HO-1 and bcr/abl using real-time PCR. Routine blood test was performed to detect the changes of leukocyte and platelet counts. The proportion of primitive cells in BM was detected by flow cytometry. The relationship between high HO-1 expression and CML progression and relapse was explored by the analysis of variance by Wilcoxon test and linear regression analysis. The diagnostic accuracy and cutoff values were determined by receiver operating characteristic curve. RESULTS: Relative expression of HO-1 mRNA in CML patients peripheral blood was significantly higher than that of donors (P < 0.0001), which were 0.57±3.78 and (1.417±1.125)×10(-6), respectively. HO-1 expression level in CML patients was 0.061 5±0.062 4, which decreased to 0.009 4±0.006 7 upon CMoR, and remained remarkably higher 0.016 3±0.017 5 than that of normal donors (1.417±1.125)×10(-6), P < 0.001. When relapse occurred, HO-1 expression significantly increased from 0.020 6±0.021 0 to 3.852±10.285 in CMoR stage and undergoing relapse. According to progression of CML, HO-1 expression level in CML patients increased from CP (0.009 5±0.017 6) to AP (0.028 0±0.055 7) and then to BP (0.276 7 ± 0.447 0). And there was a linear correlation between HO-1 expression and proportion of primitive CML cells. The diagnostic accuracies and cutoff values of HO-1 expression for CML-CP, CML-AP, and CML-BP were 1.0, 0.748, and 0.965, respectively, as well as 0.000 070, 0.001 917, and 0.020 696, respectively. CONCLUSION: HO-1 may be a potential molecular indicator for the progression and relapse of CML.

[K562 cell line resistance to nilotinib induced in vitro and preliminary investigation of its mechanisms].

OBJECTIVE: To establish a bcr-abl(+) cell line resistance to nilotinib, and to investigate the possible mechanisms of resistance. METHODS: K562 cells were treated with gradually increasing concentrations of nilotinib to generate resistance cell line K562-RN. The folder of drug-resistance was evaluated by MTT assay. Cells apoptosis rate was detected by flow cytometry, the mRNA level of bcr-abl fusion gene by FISH, and the expression of apoptosis relative gene mRNA and protein (such as bcr-abl, HO-1, mdr1, Bcl-2 and caspase-3) by RQ-PCR and western blot. RESULTS: The resistant cell line K562-RN was successfully established, with 2.01 fold resistant to nilotinib compared with K562 cell line \[the IC(50) value of nilotinib to K562 and K562-RN were (12.320 ± 1.720) µmol/L and (24.742 ± 2.310) µmol/L, respectively\]. It also had the cross resistance to adriamycin, homoharringtonine, etoposide and imatinib. Treated with different concentrations of nilotinib, cell apoptosis rate of K562-RN was significantly lower than that of K562 cells. The rate of bcr-abl gene positive cells was 92% in K562-RN by FISH assay. The mRNA and protein levels of bcr-abl, HO-1 and mdr1 expression up-regulated in K562-RN cells, while those of caspase-3 expression down-regulated, being significantly statistical difference when compared with K562 cells (P < 0.05). CONCLUSION: Human leukemic cell line resistance to nilotinib, K562-RN is established successfully by gradually increasing concentrations of drug. The mechanisms of resistance in K562-RN is probably associated with increasing expression of bcr-abl, HO-1, mdr1 and decreasing expression of caspase-3 mRNA and protein levels.