The roles of ncRNAs and histone-modifiers in regulating breast cancer stem cells

Cancer stem cells (CSCs), a subpopulation of cancer cells with ability of initiating tumorigenesis, exist in many kinds of tumors including breast cancer. Cancer stem cells contribute to treatment resistance and relapse. Conventional treatments only kill differentiated cancer cells, but spare CSCs. Combining conventional treatments with therapeutic drugs targeting to CSCs will eradicate cancer cells more efficiently. Studying the molecular mechanisms of CSCs regulation is essential for developing new therapeutic strategies. Growing evidences showed CSCs are regulated by non-coding RNA (ncRNA) including microRNAs and long non-coding RNAs (lncRNAs), and histone-modifiers, such as let-7, miR-93, miR-100, HOTAIR, Bmi-1 and EZH2. Herein we review the roles of microRNAs, lncRNAs and histone-modifiers especially Polycomb family proteins in regulating breast cancer stem cells (BCSCs).

miR-124 suppresses multiple steps of breast cancer metastasis by targeting a cohort of pro-metastatic genes in vitro / 癌症

Metastasis is a multistep process involving modification of morphology to suit migration, reduction of tumor cell adhesion to the extracellular matrix, increase of cell mobility, tumor cell resistance to anoikis, and other steps. MicroRNAs are well-suited to regulate tumor metastasis due to their capacity to repress numerous target genes in a coordinated manner, thereby enabling their intervention at multiple steps of the invasion-metastasis cascade. In this study, we identified a microRNA exemplifying these attributes, miR-124, whose expression was reduced in aggressive MDA-MB-231 and SK-3rd breast cancer cells. Down-regulation of miR-124 expression in highly aggressive breast cancer cells contributed in part to DNA hypermethylation around the promoters of the three genes encoding miR-124. Ectopic expression of miR-124 in MDA-MB-231 cells suppressed metastasis-related traits including formation of spindle-like morphology, migratory capacity, adhesion to fibronectin, and anoikis. These findings indicate that miR-124 suppresses multiple steps of metastasis by diverse mechanisms in breast cancer cells and suggest a potential application of miR-124 in breast cancer treatment.

Research Progress of Solid Tumor Stem Cells / 中山大学学报(医学科学版)

The investigation and study of cancer stem cells(CSC)have received enormous attention since the theory has been proposed,but remain topics of considerable controversy.A correct understanding of the biological characteristics of cancer stem cells and relevant mechanisms,to find new ways and methods to cure cancer are currently the most important direction.In the following text,we discuss the origin,the identification,regulatory pathway,micro-environment,the role of miRNA in the CSC and the new potential therapeutic targets elucidated by considering cancer as a problem in stem cell biology.

Effect of conjunction matrigel with MFP implantation on the tumorigenesis, proliferation, apoptosis and metastasis of breast cancer cells with different expression of Her2 / 中国病理生理杂志

AIM: To detect the effect of conjunction matrigel with mammary fad pat(MFP)implantation on the tumorigenesis, proliferation, apoptosis and metastasis of Her2 positive and negative breast cancer model. METHODS: The Her2 positive BT 474 and Her2 negative MDA-MB 231 breast cancer cells were injected into MFP of nude mice with or without matrigel to establish breast cancer model. The tumor volume was measured every 3 d. Followed up for 30 d after implantation, the nude mice were killed and the tumors and associated organs were dissected for pathological sectioning and staining with hematoxylin and eosin. The time of tumor formation and the tumorigenesis were determined after implantation. The tumor volume and metastasis rate were calculated and compared with each other. The proliferation and apoptosis of Her2 positive and negative tumors were also determined. RESULTS: Matrigel and MFP implantation technology shortened the time of tumorigenesis significantly(P<0.01). The tumorigenesis rate of BT 474 and MDA-MB 231 breast cancer cells did not show any different(P>0.05). The metastasis rate of MDA-MB 231 breast cancer cells were improved from 25.0% to 37.5%(P<0.05). CONCLUSION: Matrigel and MFP implantation can be combined to shorten the time of tumor formation by two kinds of breast cancer cells, and improve the metastasis of Her2 negative MDA-MB 231 cells. Using matrigel does not show any effect of proliferation and apoptosis on Her2 positive and negative breast cancer cells.

Effect of intrahepatic transplantation of embryonic stem cells-derived hepatic stem cells on host hepatic function and its safety evaluation / 中国组织工程研究

BACKGROUND: In vitro differentiation of embryonic stem cells into hepatocytes has been successfully reported to a certain degree; however, whether embryonic stem cells are able to effectively enter hepatic plate of host after intrahepatic transplantation, whether embryonic stem cells can further differentiate into hepatocytes and express hepatocyte function, and risk factors for neoplastic formation are still unclear at present. OBJECTIVE: To study the intrahepatic transplantation of embryonic stem cells-derived hepatic stem cells in therapeutic liver repopulation models, and to investigate the liver tissue replacement, growth and differentiation in vivo, and neoplastic formation.DESIGN: Randomized controlled animal study.SETTING: Department of Pediatric Surgery, the Second Hospital affiliated to Sun Yat-sen University. MATERIALS: Twenty-four BALB/c mice, 6-8 weeks old, weighing 20-35 g, irrespective of gender, were provided by Guangzhou Experimental Animal Center. Embryonic stem cells-derived hepatic stem cells were differentiated from embryonic stem cells. E14 was provided by Stem cell Center of our hospital. METHODS: This study was performed at the Stem Cell Center, the Second Hospital affiliated to Sun Yat-sen University from July 2006 to June 2007. Twenty-four mice were randomly divided into a liver repopulation model + stem cell transplantation group (group A) and a liver resection + stem cell transplantation group (group B), with 12 mice in each group. Mice in the group A were intraperitoneally injected with 50 mg/kg retrorsine once every two weeks for totally twice. Four weeks after the second injection, about 70% liver was resected. And then, the embryonic stem cells-derived hepatic stem cells, labeled by 1×105 carboxy fluoresce in diacetate succinimidyl ester (CFDA-SE), were transplanted into mouse liver through portal vein. On the other hand, 70% liver of mice in the group B was resected and embryonic stem cells-derived hepatic stem cells were transplanted into mouse liver. MAIN OUTCOME MEASURES: The distribution, incorporation, and proliferation of transplanted cells were observed under fluorescent microscopy. Two weeks later, hepatic function was stained with albumin fluorescence immunoassay (double fluorescence staining) and assayed by level of serum albumin. Embryonic stem cells-derived hepatic stem cells were poured into liver of remedial liver regeneration mice, and undifferentiated embryonic stem cells were transplanted into subcutaneous tissue in axillary region as the controls to observe neoplastic formation in embryonic stem cells-derived hepatic stem cells. RESULTS: ① Growth of hepatic stem cells in recipient mice: One week after transplantation of CFDA-SE-labeled embryonic stem cells-derived hepatic stem cells, some scattered region was green under fluorescent microscopy. The area of green region increased apparently in 2 weeks, and cord-like structure could be observed. ② Liver function: Immunofluorescent staining of albumin (double fluorescence staining) demonstrated that labeled cells expressed positive albumin (yellow fluorescence) in liver tissue of recipient mice, but there was not significant difference in serum albumin level between group A and group B (P > 0.05). ③ Reliability of hepatic stem cell transplantation: Teratoma did not form over 6 months; however, transplantation of undifferentiated embryonic stem cells in the axillary region could cause formation of teratoma after 6 weeks. CONCLUSION: The transplantation of embryonic stem cells-derived hepatic stem cells in therapeutic liver repopulation model mice can effectively and further grow and differentiate, or even partially express hepatocyte function; in particular, the transplantation is safe.

Application of ESC-derived hepatic stem cells in therapeutic liver repopulation / 中国病理生理杂志

0.05).No teratoma was formed in the experimental group,while a large teratoma was observed in control group in 6 weeks post-transplantation.CONCLUSION:The ESC-derived hepatic stem cells are normally incorporated into mouse liver parenchymal structure,proliferate and differentiate further in vivo and possess some hepatic functions without forming teratomas.

The anti-apoptotic effects of Caspase inhibitor Ⅰ on cultured hepatocytes / 中国普通外科杂志

0 05) Under the same treatment concentration of rsFasL or granzyme B, percentage in TUNEL positive staining and Caspase 3 activity in the experimental group were much lower than those in the control group ( P