Digital gene expression profiling analysis of DNA repair pathways in colon cancer stem population of HT29 cells

Long non-coding RNA MBNL1-AS1 regulates proliferation, migration, and invasion of cancer stem cells in colon cancer by interacting with MYL9 via sponging microRNA-412-3p

BACKGROUND/AIMS

Colon cancer is a common cancer that is a threat to human health. Some long non-coding RNAs (lncRNAs) have been observed to exert roles in colon cancer. Here, the current study is aimed to explore the potential mechanism of lncRNA MBNL1 antisense RNA 1 (MBNL1-AS1) in progression of colon cancer and the associated mechanisms.

METHODS

Microarray analysis was performed to screen differentially expressed lncRNA and genes associated with colon cancer and its potential mechanism. The functional role of MBNL1-AS1 in colon cancer was analyzed, followed identification of the interaction among MBNL1-AS1, microRNA-412-3p (miR-412-3p), and MYL9. Subsequently, CSC viability, migration, invasion, and apoptosis were detected though a series of in vitro experiments. At last, in vivo experiments were performed to assess tumor formation of colon CSCs.

RESULTS

MBNL1-AS1 and MYL9 were poorly expressed in colon cancer. MBNL1-AS1 could competitively bind to miR-412-3p so as to promote MYL9 expression. Enhancement of MBNL1-AS1 or inhibition of miR-412-3p was shown to decrease CSC proliferation, migration, and invasion but promote apoptosis. Moreover, MBNL1-AS1 reversed the CSC-like properties as well as xenograft tumor formation in vivo induced by miR-412-3p.

CONCLUSION

Collectively, the present study suggests an inhibitory role of MBNL1-AS1 in colon cancer by upregulating miR-412-3p-targeted MYL9. Thus, this study provides an enhanced understanding of MBNL1-AS1 along with miR-412-3p and MYL9 as therapeutic targets for colon cancer.

The Marine Dinoflagellate Alexandrium andersoni Induces Cell Death in Lung and Colorectal Tumor Cell Lines

Dinoflagellates are one of the most important components in marine phytoplankton, second only to diatoms as primary producers. Dinoflagellates have also been reported to produce bioactive secondary metabolites such as polyethers and macrolides with potential applications as pharmaceuticals. Here, we tested the effect of the organic extract and its related enriched extracts from solid-phase extraction (SPE) of a strain of the dinoflagellate Alexandrium andersoni. We found that the SPE extracts induced high cytotoxicity towards two cancer cell lines (A549 lung cancer and HT29 colorectal cancer) without affecting normal cell viability. The SPE extracts activated two different cell death pathways in the two tumor cell lines at the gene expression level, with the involvement of the major mediators of the tumor necrosis factor (TNF) cell signaling cascade. In HT29 cells, in addition to TNF activation, a death signaling pathway in response to DNA damage was also induced. This is an interesting finding since the HT29 cell line is highly aggressive since it is p53 gene-defect and this DNA instability renders this type of cancer very resistant towards all chemotherapeutic agents. Another significant result is that two distinct chemical fractions were selectively able to induce different and specific responses on the two different tumor cells treated.

Reactive Oxygen Species-Mediated Autophagy Defines the Fate of Cancer Stem Cells

Significance: A fraction of tumorigenic cells, also known as tumor initiating or cancer stem cells (CSCs), is thought to drive tumor growth, metastasis, and chemoresistance. However, little is known regarding mechanisms that convey relevant pathways contributing to their self-renewal, proliferation, and differentiation abilities. Recent Advances: Recent works on CSCs provide evidence on the role of redox disruption and regulation of autophagic flux. This has been linked to increased DNA repair capacity and chemoresistance. Critical Issues: The current review summarizes the most recent studies assessing the role of redox homeostasis, autophagy, and chemoresistance in CSCs, including some novel findings on microRNAs and their role in horizontal transfer within cancer cell populations. Future Directions: Rational anticancer therapy and prevention should rely on the fact that cancer is a redox disease with the CSCs being the apex modulated by redox-mediated autophagy. Antioxid. Redox Signal. 28, 1066-1079.