Dietary compound isoliquiritigenin prevents mammary carcinogenesis by inhibiting breast cancer stem cells through WIF1 demethylation

Isoliquiritigenin attenuates MiR-21 expression via induction of PIAS3 in breast cancer cells

Activated STAT3 triggered miR-21 transcription via binding to its promoter. ISL induced PIAS3 expression, a specific inhibitor of activated STAT3, leading to inhibition of STAT3 signaling and subsequent miR-21 transcription in breast cancer cells.

Targeting cancer stem cells and signaling pathways by phytochemicals: Novel approach for breast cancer therapy

Breast cancer is the most common form of cancer diagnosed in women worldwide and the second leading cause of cancer-related deaths in the USA. Despite the development of newer diagnostic methods, selective as well as targeted chemotherapies and their combinations, surgery, hormonal therapy, radiotherapy, breast cancer recurrence, metastasis and drug resistance are still the major problems for breast cancer. Emerging evidence suggest the existence of cancer stem cells (CSCs), a population of cells with the capacity to self-renew, differentiate and be capable of initiating and sustaining tumor growth. In addition, CSCs are believed to be responsible for cancer recurrence, anticancer drug resistance, and metastasis. Hence, compounds targeting breast CSCs may be better therapeutic agents for treating breast cancer and control recurrence and metastasis. Naturally occurring compounds, mainly phytochemicals have gained immense attention in recent times because of their wide safety profile, ability to target heterogeneous populations of cancer cells as well as CSCs, and their key signaling pathways. Therefore, in the present review article, we summarize our current understanding of breast CSCs and their signaling pathways, and the phytochemicals that affect these cells including curcumin, resveratrol, tea polyphenols (epigallocatechin-3-gallate, epigallocatechin), sulforaphane, genistein, indole-3-carbinol, 3, 3'-di-indolylmethane, vitamin E, retinoic acid, quercetin, parthenolide, triptolide, 6-shogaol, pterostilbene, isoliquiritigenin, celastrol, and koenimbin. These phytochemicals may serve as novel therapeutic agents for breast cancer treatment and future leads for drug development.

DNA methylation in adult diffuse gliomas

Adult diffuse gliomas account for the majority of primary malignant brain tumours, and are in most cases lethal. Current therapies are often only marginally effective, and improved options will almost certainly benefit from further insight into the various processes contributing to gliomagenesis and pathology. While molecular characterization of these tumours classifies them on the basis of genetic alterations and chromosomal abnormalities, DNA methylation patterns are increasingly understood to play a role in glioma pathogenesis. Indeed, a subset of gliomas associated with improved survival is characterized by the glioma CpG island methylator phenotype (G-CIMP), which can be induced by the expression of mutant isocitrate dehydrogenase (IDH1/2). Aberrant methylation of particular genes or regulatory elements, within the context of G-CIMP-positive and/or negative tumours, has also been shown to be associated with differential survival. In this review, we provide an overview of the current knowledge regarding the role of DNA methylation in adult diffuse gliomas. In particular, we discuss IDH mutations and G-CIMP, MGMT promoter methylation, DNA methylation-mediated microRNA regulation and aberrant methylation of specific genes or groups of genes.

MicroR-760 suppresses cancer stem cell subpopulation and breast cancer cell proliferation and metastasis: By down-regulating NANOG

BACKGROUND AND OBJECTIVE

Emerging evidences suggest that cancer stem cells are responsible for tumor aggressive, metastasis and therapeutic resistance. To data, the mechanism underlying breast cancer stem cell (BCSC) population within tumor metastasis remains to be fully elucidated. The current study was to investigate the potential role of microRNA-760 (miR-760) and its associated target gene in population and metastasis of BCSC.

METHODS

Characteristic BCSCs surface markers (CD44(+)/CD24(-/low)) were determined by flow cytometry in breast cancer MCF-7 and BT-549 cells. Quantitative RT-PCR was used to evaluate miR-760 and NANOG mRNA expression. Expression of NANOG protein was determined using western blot. Cell proliferation was determined by MTT assay. The model of breast cancer cell xenograft was used to evaluate the effect of miR-760 on tumor growth.

RESULTS

BT-549 cell has substantially more CD44(+)/CD24(-/low) subpopulation than MCF-7 cell. Moreover, BT-549 cell expressed lower level of miR-760 and higher level of NANOG than MCF-7cell. By result from cellular miR-760 modulation, we found that miR-760 overexpression suppressed CD44(+)/CD24(-/low) population as well as inhibited cell proliferation and migration of BT-549. On the contrary, knockdown of miR-760 promoted CD44(+)/CD24(-/low) population and migration of MCF-7 cells. By luciferase reporter assay, miR-760 was proved to be functional associated with NANOG via regulating its expression. This functional interaction was showed to be involved in controlling proliferation and migration of MCF-7 and BT-549 cell.

CONCLUSION

These data suggest that the target of miR-760/NANOG axis may represent a new therapeutic approach to suppress breast cancer stem cell subpopulation thereby prevent cancer metastasis.