Increased HoxB4 Inhibits Apoptotic Cell Death in Pro-B Cells

HOXB4 promotes the malignant progression of ovarian cancer via DHDDS

Background

Homeobox B4 (HOXB4) is correlated with poor prognosis of various cancer types. However, how HOXB4 promotes ovarian cancer (OV) progression remains unclear.

Methods

The Cancer Genome Atlas (TCGA) database indicated that a high level of HOXB4 in OV was correlated with poor prognosis. The biological functions of HOXB4 were confirmed by colony formation, migration, and invasion assays. The effect of HOXB4 on the expression of EMT cell markers was determined. The transcriptional target of HOXB4 was DHDDS, which was detected by a ChIP assay. A xenograft tumor model was generated in nude mice to detect the role of HOXB4 in tumor proliferation and metastasis.

Results

The results showed that HOXB4 protein levels were higher in OV tissues than in normal tissues and correlated with poor prognosis of OV. HOXB4 reduction inhibited the proliferation and invasion ability of OV cells in vitro. Conversely, these effects were enhanced by the upregulation of HOXB4 in OV cells. The binding of HOXB4 to two DNA motifs regulated DHDDS expression and contributed to the malignant progression of OV. The role of HOXB4 in contributing to tumor development in vivo was verified in mice. Further results indicated that HOXB4 induced Snail and Zeb1 expression.

Conclusion

Overall, HOXB4 overexpression was remarkably correlated with poor prognosis of OV. Mechanistically, HOXB4 enhances the proliferation and invasion of tumor cells by activating DHDDS, thereby promoting the malignant progression of OV.

Effect of Ghrelin on Caspase 3 and Bcl2 Gene Expression in H2O2 Treated Rat's Bone Marrow Stromal Cells

Purpose: The antiapoptotic effect of ghrelin in various cell lines including bone marrow stromal cells (BMSCs) has been proved. However, the real mechanism of this effect is not clear. Caspase3 and Bcl2 are well-known pro- and antiapoptotic regulatory genes in eukaryotes. The aim of the study was to find out the effect of ghrelin on Caspase 3 and Bcl2 change in BMSCs.

Methods: Rat BMSCs were cultivated in DMEM. Passage 3 BMSCs were treated with ghrelin 100 μM for 48 h. Real-time PCR for Caspase 3 and Bcl2 was carried out from B (untreated BMSCs), BH (BMSCs treated with 125 µM H2O2), BGH (BMSCs treated with 100 µM ghrelin then 125 µM H2O2) and BG (BMSCs treated with 100 µM ghrelin) groups. For immunofluorescence, cells were incubated with anti Caspase 3 and Bcl2monoclonal antibodies. Primary antibodies were visualized using the FITC method. All data are presented as means ± SEM. Values of P<0.05 were considered statistically significant.

Results: Ghrelin decreased mRNA expressions of Caspase-3 significantly as compared to the BH group (P<0.05). Also, Bcl-2 gene expression showed an increment in BG group as compare with BH and BGH groups (P<0.05). A high present of Bcl-2 positive cells were observed in the BGH group while Caspase-3 positive cells were significantly decreased in the BGH group compared with the BH group (P<0.05).

Conclusion: Ghrelin probably enhances BMSCs viability through regulation of pro- and antiapoptotic genes Caspase 3 and Bcl2. However the signaling pathway of this effect should be elucidated in the future.

Ghrelin Upregulates Hoxb4 Gene Expression in Rat Bone Marrow Stromal Cells

OBJECTIVES

Ghrelin is a peptide which has a proliferative and antiapoptotic effect in many cells including bone marrow stromal cells (BMSCs). Homeobox protein B4 (HOXB4) is a transcription factor involved in stem cell regeneration and survival. The aim of the study was to find out the efect of ghrelin on Hoxb4 expression in BMSCs.

MATERIALS AND METHODS

In this experimental study, rat BMSCs were cultivated in Dulbecco's Modified Eagle Medium (DMEM). Passage three BMSCs were treated with ghrelin 100 μM for 48 hours. Real-time polymerase chain reaction (PCR) was carried out from the untreated BMSCs (B), BMSCs treated with 125 μM H₂O₂ (BH), BMSCs treated with 100 μM ghrelin then 125 μM H₂O₂ (BGH) and BMSCs treated with 100 μM ghrelin (BG) groups. For immunofluorescence, cells were incubated with an anti-HOXB4 monoclonal antibody. Primary antibodies were visualized using the Fluorescein isothiocyanate (FITC) method. All data are presented as mean ± SEM and P<0.05 was considered as statistical significant.

RESULTS

Hoxb4 expression significantly increased in the BG compared with BH and BGH groups. Furthermore, 100 μM ghrelin, increased the mean of HOXB4 positive immunoreactive cells compared to the BH group.

CONCLUSIONS

Ghrelin probably enhances proliferation and viability of BMSCs through Hoxb4 upregulation. However, the signaling pathway and other biological outcomes of this effect should be elucidated in different stem cells.

Comparison of ectopic gene expression methods in rat neural stem cells

Neural stem cells (NSCs) have the ability to proliferate and differentiate into various types of cells that compose the nervous system. To study functions of genes in stem cell biology, genes or siRNAs need to be transfected. However, it is difficult to transfect ectopic genes into NSCs. Thus to identify the suitable method to achieve high transfection efficiency, we compared lipid transfection, electroporation, nucleofection and retroviral transduction. Among the methods that we tested, we found that nucleofection and retroviral transduction showed significantly increased transfection efficiency. In addition, with retroviral transduction of Ngn2 that is known to induce neurogenesis in various types of cells, we observed facilitated final cell division in rat NSCs. These data suggest that nucleofection and retroviral transduction provide high efficiency of gene delivery system to study functions of genes in rat NSCs.