FOXK2 transcription factor and its roles in tumorigenesis (Review).

Forkhead box K2 (FOXK2) is a central transcriptional regulator of embryonic development and cell homeostasis. Since its discovery, evidence has shown that FOXK2 mediates a variety of biological processes involving in genomic stability, DNA repair, cancer stem cell maintenance, cell proliferation, apoptosis and cell metabolism. The inherent structural characteristics of FOXK2 enable it as a transcriptional factor (TF) to cooperate with other active molecules in cancer development. FOXK2 mediates several significant chromatin events that are necessary for some chromatin accessibility and protein-protein interaction. FOXK2 is involved in the pathogenesis of a number of types of cancer as an oncoprotein or tumor suppressor depending on its interactive partners. Therefore, the loss of FOXK2 and its functions directly or indirectly affect the fate of cells. FOXK2 expresses differentially in a number of types of cancer and is involved in a number of aspects of carcinogenesis. However, its roles in tumorigenesis remain largely unexplored. The present review focused on the latest findings and evidence on the broad roles and possible mediating mechanisms of FOXK2 in carcinogenesis. The recent findings about FOXK2 may shed light on the direction of future FOXK2 research in tumorigenesis.

JMJD1C-regulated lipid synthesis contributes to the maintenance of MLL-rearranged acute myeloid leukemia.

Mixed Lineage Leukemia rearranged acute myeloid leukemia (MLLr AML) predicts a poor prognosis. Histone demethylase JMJD1C is a potential druggable target of MLLr AML. However, little is known about how JMJD1C contributes to MLLr AML. Here we found that JMJD1C regulates lipid synthesis-associated genes including FADS2, SCD in MLLr AML cells. Lipid synthesis-associated protein FABP5 was identified as a specific interacting protein of JMJD1C and binds to the jumonji domain of JMJD1C. FABP5 also regulates JMJD1C mRNA and protein expression. JDI-10, a small molecular inhibitor of JMJD1C identified by us, represses MLLr AML cells, induces apoptosis, and decreases JMJD1C-regulated lipid synthesis genes. Moreover, JDI-10 mediated suppression of MLLr AML cells can be rescued by palmitic acid, oleic acid, or recombinant FABP5. In summary, we identified that JMJD1C-regulated lipid synthesis contributes to the maintenance of MLLr AML. Lipid synthesis repression may represent a new direction for the treatment of MLLr AML.

KDM2A Targets PFKFB3 for Ubiquitylation to Inhibit the Proliferation and Angiogenesis of Multiple Myeloma Cells.

The lysine demethylase KDM2A (also known as JHDM1A or FBXL11) demethylates histone H3 at lysine K36 which lead to epigenetic regulation of cell proliferation and tumorigenesis. However, many biological processes are mediated by KDM2A independently by its histone demethylation activity. In the present study, we aimed to characterize the functional significance of KDM2A in multiple myeloma (MM) disease progression. Specifically, we defined that one of the key enzymes of glycolysis PFKFB3 (6-phosphofructo-2-kinase) is ubiquitylated by KDM2A which suppresses MM cell proliferation. Previous study showed that KDM2A and PFKFB3 promoted angiogenesis in various tumor cells. We further reveal that KDM2A targets PFKFB3 for ubiquitination and degradation to inhibit angiogenesis. Several angiogenic cytokines are also downregulated in MM. Clinically, MM patients with low KDM2A and high PFKFB3 levels have shown worse prognosis. These results reveal a novel function of KDM2A through ubiquitin ligase activity by targeting PFKFB3 to induce proliferation, glycolysis and angiogenesis in MM cells. The data provides a new potential mechanism and strategy for MM treatment.

Jiyuan Oridonin A Overcomes Differentiation Blockade in Acute Myeloid Leukemia Cells With MLL Rearrangements via Multiple Signaling Pathways.

Differentiation therapy with all-trans-retinoic acid (ATRA) in acute promyelocytic leukemia (APL), a subtype of acute myeloid leukemia (AML), has been extremely successful in inducing clinical remission in APL patients. However, the differentiation therapy of ATRA-based treatment has not been effective in other subtypes of AML. In this study, we evaluated a small molecule of ent-kaurene diterpenoid, Jiyuan oridonin A (JOA), on the differentiation blockade in AML cells with the mixed lineage leukemia (MLL) gene rearrangements (MLLr) in MV4-11, MOLM-13 and THP-1 cells. We found that JOA could significantly inhibit the proliferation of MOLM-13, MV4-11 and THP-1 cells. Moreover, JOA promoted cell differentiation coupled with cell-cycle exit at G0/G1 and inhibited the colony- forming capacity of these cells. We showed that the anti-proliferative effect of JOA attributed to cell differentiation is most likely through the martens tretinoin response up pathway in the MOLM-13 cell line, and the hematopoietic cell lineage pathway by the inhibition of c-KIT expression and cell adhesion pathway in the THP-1 cell line. Our findings suggest that JOA could be a novel therapeutic agent against human MLLr acute myeloid leukemia.

Modulators of histone demethylase JMJD1C selectively target leukemic stem cells.

Leukemic stem cells (LSCs) comprise a very rare cell population that results in the development of acute myeloid leukemia. The selective targeting of drivers in LSCs with small molecule inhibitors holds promise for treatment of acute myeloid leukemia. Recently, we reported the identification of inhibitors of the histone lysine demethylase JMJD1C that preferentially kill MLL rearranged acute leukemia cells. Here, we report the identification of jumonji domain modulator #7 (JDM-7). Surface plasmon resonance analysis showed that JDM-7 binds to JMJD1C and its family homolog JMJD1B. JDM-7 did not significantly suppress cell proliferation in liquid cell culture at higher doses, although it led to a significant decrease in semi-solid colony formation experiments at lower concentrations. Moreover, low doses of JDM-7 did not suppress the proliferation of erythroid progenitor cells. We identified that JDM-7 downregulates the LSC self-renewal gene HOXA9 in leukemia cells. We further found that the structure of JDM-7 is similar to that of tadalafil, a drug approved by the US Food and Drug Administration. Molecular docking and surface plasmon resonance analysis showed that tadalafil binds to JMJD1C. Moreover, similar to JDM-7, tadalafil suppressed colony formation of leukemia cells in semi-solid cell culture at a concentration that did not affect primary umbilical cord blood cells. In summary, we have identified JDM-7 and tadalafil as potential JMJD1C modulators that selectively inhibit the growth of LSCs.

Small molecular modulators of JMJD1C preferentially inhibit growth of leukemia cells.

Histone demethylases are promising therapeutic targets as they play fundamental roles for survival of Mixed lineage leukemia rearranged acute leukemia (MLLr AL). Here we focused on the catalytic Jumonji domain of histone H3 lysine 9 (H3K9) demethylase JMJD1C to screen for potential small molecular modulators from 149,519 natural products and 33,765 Chinese medicine components via virtual screening. JMJD1C Jumonji domain inhibitor 4 (JDI-4) and JDI-12 that share a common structural backbone were detected within the top 15 compounds. Surface plasmon resonance analysis showed that JDI-4 and JDI-12 bind to JMJD1C and its family homolog KDM3B with modest affinity. In vitro demethylation assays showed that JDI-4 can reverse the H3K9 demethylation conferred by KDM3B. In vivo demethylation assays indicated that JDI-4 and JDI-12 could induce the global increase of H3K9 methylation. Cell proliferation and colony formation assays documented that JDI-4 and JDI-12 kill MLLr AL and other malignant hematopoietic cells, but not leukemia cells resistant to JMJD1C depletion or cord blood cells. Furthermore, JDI-16, among multiple compounds structurally akin to JDI-4/JDI-12, exhibits superior killing activities against malignant hematopoietic cells compared to JDI-4/JDI-12. Mechanistically, JDI-16 not only induces apoptosis but also differentiation of MLLr AL cells. RNA sequencing and quantitative PCR showed that JDI-16 induced gene expression associated with cell metabolism; targeted metabolomics revealed that JDI-16 downregulates lactic acids, NADP+ and other metabolites. Moreover, JDI-16 collaborates with all-trans retinoic acid to repress MLLr AML cells. In summary, we identified bona fide JMJD1C inhibitors that induce preferential death of MLLr AL cells.

KDM3B shows tumor-suppressive activity and transcriptionally regulates HOXA1 through retinoic acid response elements in acute myeloid leukemia.

KDM3B reportedly shows both tumor-suppressive and tumor-promoting activities in leukemia. The function of KDM3B is likely cell-type dependent and its seeming functional discordance may reflect its phenotypic dependence on downstream targets. Here, we first showed the underexpression of KDM3B in acute myeloid leukemia (AML) patients and AML cell lines with MLL-AF6/9 or PML-RARA translocations. Overexpression of KDM3B repressed colony formation of AML cell line with 5q deletion. We then performed global microarray profiling to identify potential downstream targets of KDM3B, notably HOXA1, which was verified by real time PCR and Western blotting. We further showed KDM3B binding at retinoic acid response elements (RARE) but not at the promoter region of HOXA1 gene. KDM3B knockdown resulted in increased mono-methylation but decreased di-methylation of H3K9 at RARE while eschewing the promoter region of HOXA1. Collectively, we found that KDM3B exhibits potential tumor-suppressive activity and transcriptionally modulates HOXA1 expression via RARE in AML.

[Effect of Human Umbilical Cord-derived Mesenchymal Stem Cells on Proliferation and Differentiation of Leukemia Cells].

OBJECTIVE: To investigate the effect of human umbilical cord-derived mesenchymal stem cells(HUC-MSC) on the proliferation and differentiation of NB4 treated with all-trans retinoid acid (ATRA) and its underlining mechanisms . METHODS: Human umbilical cord mesenchymal stem cells were isolated from umbilical cord of newborns. Co-culture system was established by HUC-MSC and NB4 in vitro. The experiment was divided into 4 groups: NB4 group (NB4 cells alone) , NM group (NB4 cells co-cultured with HUC-MSC) , NA group (NB4 cells treated with ATRA) , NMA group (NB4 cells co-cultured with HUC-MSC and treated with ATRA) . NB4 cells were counted by a microscopy, NB4 proliferation was monitored by CCK-8 assay, NB4 differentiation was assessed by Wright ' s staining and nitroblue tetrazolium reduction test. IL-6 levels in the culture supernatant of different groups were tested by ELISA kit. Quantitative PCR was used to detect the transcription level of CDKN1A, CCND1 and Survivin. RESULTS: NB4 and HUC-MSC in the co-culturing systems were in good condition with a slight repression of NB4 proliferation by HUC-MSC. HUC-MSC could collaborate with ATRA to induce significant NB4 differentiation. Consistent with this finding, IL-6 expression levels of co-cultured groups were remarkably higher than that in any other groups or the group of HUC-MSC alone. The quantitative PCR analysis showed that the levels of CDKN1A and CCND1 mRNA expression were increased or decreased respectively in the co-cultured groups. CONCLUSION: HUC-MSC co-culture can reduce proliferation but promote the differentiation of NB4 cells, suggesting that this effect may be closely related with the secretion of IL-6 which can affect the expression of some factors in vitro.

[Comparison of Several Optimization Schemes for the Induction and Expansion of Antibody-Mediated High Efficiency CIK (AMHE-CIK) In Vitro].

OBJECTIVE: To compare several schemes of inducing and expanding the antibody-mediated high efficiency CIK (AMHE-CIK) in vitro, so as to find out a method that can acquire a large number of cells capable to kill the tumor cells in a short time. METHODS: Peripheral blood mononuclear cells (PBMNC) from healthy volunteers was isolated and activated with CD3 antibody, then were cultured with the addition of different cytokines (IL-2, IL-4, G-CSF, GM-CSF, IFN-γ, TNF-α) for 14 days in vitro. The morphological changes of cells were observed by light microscopy. Based on the immunophenotypes of cells in each groups analyzed by flow cytometry, the cytokines capable to induce the dendritic cells and killer cells were screened out, respectively. According to different combination of cytokines, the cells were divided 4 groups: control, IL-2, group 1 (componant A included IL-2, IL-4, and GM-CSF. Componant B included IL-2, G-CSF, IFN-γ, and TNF-α), and group 2 (componant A included IL-2, IL-4, and GM-CSF. Componant B included IL-2, IL-4, G-CSF, IFN-γ, and TNF-α). The proliferation and differentiation of CD3(+) CD8(+) and CD3(+) CD56(+) cells were measured by flow cytometry after culture in vitro for 7 days. RESULTS: After inducing and expanding in vitro for 7 days, the cell proliferation rate of control group, IL-2 group, group 1 and group 2 were 1.57 ± 0.01, 4.17 ± 0.16, 5 ± 0.47, 7.17 ± 0.24-folds, respectively. The differences between IL-2 group, group 1, group 2 and control group were statistically significant (P < 0.05). The immunophenotype analysis showed that the proportion of CD3(+) CD8(+) induced by each protocol was 13.96 ± 0.23%, 26.33 ± 0.55%, 36.83 ± 0.34% and 35.88 ± 0.16%, respectively. The proportion of CD3(+) CD8(+) in group 1 and 2 was higher than that in IL-2 group (P < 0.05), but the difference between them was not significant (P < 0.05). The proportions of CD3(+) CD56(+) induced by each protocol were 11.03 ± 0.28%, 29.31 ± 0.60%, 39.96 ± 0.38% and 29.33 ± 0.54%, respectively, the proportion of group 1 was higher than that of IL-2 group and group 2 (P < 0.05), but the difference between IL-2 group and group 2 was not significant (P < 0.05). CONCLUSION: The group 1 protocol obtained from this study can promote the proliferation of DC-CIK and also increase the proportion of the tumor killing cells (CD3(+) CD8(+) and CD3(+) CD56(+)).

A Critical Role of miR-144 in Diffuse Large B-cell Lymphoma Proliferation and Invasion.

MicroRNAs are endogenous noncoding RNAs that play important roles in a wide variety of biologic processes such as apoptosis, development, aging, and tumorigenesis. The B-cell lymphoma 6 (BCL6) transcriptional repressor has emerged as a critical therapeutic target in diffuse large B-cell lymphomas (DLBCL), but the mechanisms regulating BCL6 are still unclear. In the current study, we screened the microRNA expression profiles in DLBCL specimens and cell lines by qRT-PCR and found that the expression of miR-144 was significantly downregulated in DLBCL tissues and cell lines and negatively correlated with BCL6 expression. We further demonstrated that BCL6 was the direct target gene of miR-144, and miR-144 suppressed the expression of BCL6 via binding the 3'untranslated region of BCL6 mRNA. Biologically, forced expression of miR-144 significantly attenuated cell proliferation and invasion of OCI-Ly3 cells in vitro, and the tumor-suppressor effect of miR-144 was also confirmed using a xenograft mouse model in vivo Taken together, our results reveal that miR-144 regulates BCL6 in DLBCL and provide a rationale for developing strategies that target miR-144 as a therapeutic intervention for DLBCL.

Risk factors for adolescent smoking in urban and rural China: findings from the China seven cities study.

Cigarette smoking is rising among urban Chinese adolescents and poses a significant public health concern. The majority of Chinese youth live in rural areas, but most research on the risk factors for smoking has been conducted in urban areas of China. This study examined the associations between parental smoking, peer smoking, and low refusal self-efficacy and smoking among urban and rural Chinese youth. This analysis used a cross-sectional sample of 3412 ninth grade students in urban and rural areas under the administrative jurisdiction of seven large cities in China. Multilevel logistic regression models were used to associate the risk factors with lifetime and current smoking, separately in boys and girls. Adolescent smoking was not strongly associated with parental smoking. However it was strongly associated with peer smoking and low refusal self-efficacy across both the urban and rural samples. Students with lower refusal self-efficacy were approximately 5-17 times more likely to be lifetime or current smokers than those with higher refusal self-efficacy. Smoking prevention interventions in China may need to focus on raising adolescents' refusal self-efficacy.