ABSTRACT
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).
Subject(s)
Humans , Breast Neoplasms , Genetics , Metabolism , Pathology , Histones , Metabolism , Neoplastic Stem Cells , Metabolism , RNA, Untranslated , Genetics , MetabolismABSTRACT
CONTEXT: Changes in genome, made by multiple genetic and epigenetic alterations result to the cancer initiation and progression. Suppressor of zeste 12 (SUZ12) and chromobox homolog 8 (CBX8) proteins are two components of epigenetic regulators that their function in the initiation and progression of cancers are not well‑understood. AIMS: The role of SUZ12 and its target CBX8 is examined. SETTINGS AND DESIGN: Comparing the expression levels of SUZ12 and CBX8 between 30 gastric tumor and their marginal tissues. MATERIALS AND METHODS: Quantitative reverse transcription polymerase chain reaction technique was performed. STATISTICAL ANALYSIS: Statistical comparison was carried out using Statistical Program for Social Sciences software 16.0 (Released 2007, SPSS for Windows. SPSS Inc., Chicago, IL, USA) and (GraphPad Prism version 5 for Windows, GraphPad Software, La Jolla, California USA, ww.graphpad.com). RESULTS: Despite the obvious differences in the expression of these genes in each sample for tumor and its marginal tissue, statistical analysis did not show significant differences in the mean of expression for SUZ12 and CBX8 genes in total. Due to the variation in expression levels, the samples could be divided into two groups for each gene; group 1, in which the genes were overexpressed in tumor and group 2, in which the genes were down regulated in tumor samples. CONCLUSION: We found that in each group, the difference in the SUZ12 and CBX8 genes expression were significantly divergent between tumors and their marginal tissues. It means that the regulatory mechanisms involved in developing and controlling the process of gastric cancer pathogenesis is more complex than it thought. These results also bring new evidence on the possible double origin for gastric cancer development, bone‑marrow‑derived cells and tissue stem cells.
ABSTRACT
Cancer stem cells comprise a sub-population with the capacity of self-renewal,self-differentiation and high tumorigenicity.Cancerogenesis,development,relapse and therapeutic resistance are closely related with these cells.The most important characteristics of these cells are the ability to self-renew.So insight into the regulating mechanism of self-renewal in cancer stem cells will be important for the development of novel molecular agents targeted the cancer stem cells.
ABSTRACT
Transcriptional regulation of a gene is not always correlated with genetic information inherited from parents because the transcription of specific genes is often governed by the modification of chromatin structure. The study of transcriptional regulation by modifying chromatin structure is well-known as "epigenetics". Several methods involved in the modification of chromatin structure have been developed in the mammalian species during evolution. Among those methods, methylations of specific DNA region or histone are often used to control specific gene transcription. Therefore, understanding the activity of proteins involved in DNA or histone methylation is an initial step to control the transcriptional activity of a specific gene. Polycomb group (PcG) proteins were known to be repressors of transcription of a specific gene by creating and maintaining methylation or ubiquitination of the specific region of histone. Dependent on the target histone, the activity of PcG proteins effects on the development of specific lineage cells or the activity of specific cell types. In this review, the function, expression and activity of PcG proteins related with the development or activation of T cells are discussed.