The long non-coding RNA ET-20 mediates EMT by impairing desmosomes in breast cancer cells

The vast majority of breast cancer-associated deaths are due to metastatic spread of cancer cells, a process aided by epithelial-mesenchymal transition (EMT). Mounting evidence has indicated that long non-coding RNAs (lncRNAs) also contribute to tumor progression. We report the identification of 114 novel lncRNAs that change their expression during TGFβ-induced EMT in murine breast cancer cells (referred to as EMT-associated transcripts; ETs). Of these, the ET-20 gene localizes in antisense orientation within the Tenascin C (Tnc) gene locus. Tnc is an extra-cellular matrix protein which is critical for EMT and metastasis formation. Both ET-20 and Tnc are regulated by the EMT master transcription factor Sox4. Notably, ablation of ET-20 lncRNA effectively blocks Tnc expression and with it EMT. Mechanistically, ET-20 interacts with desmosomal proteins, thereby impairing epithelial desmosomes and promoting EMT. A short transcript variant of ET-20 is found upregulated in invasive human breast cancer cell lines where it also promotes EMT. Targeting ET-20 appears a therapeutically attractive lead to restrain EMT and breast cancer metastasis in addition to its potential utility as a biomarker for invasive breast cancer.

The Effects of Trifolium pratense L. Sprouts’ Phenolic Compounds on Cell Growth and Migration of MDA-MB-231, MCF-7 and HUVEC Cells

Uncontrolled growth and migration and invasion abilities are common for cancer cells in malignant tumors with low therapeutic effectiveness and high mortality and morbidity. Estrogen receptor β (ERβ), as a member of the nuclear receptor superfamily, shows potent tumor suppressive activities in many cancers. Phytoestrogens’ structural resemblance to 17 β-estradiol allows their binding to ERβ isoform predominantly, and therefore, expression of genes connected with elevated proliferation, motility and invasiveness of cancer cells may be downregulated. Among polyphenolic compounds with phytoestrogenic activity, there are isoflavones from Trifolium pratense L. (red clover) sprouts, containing high amounts of formononetin and biochanin A and their glycosides. To determine the source of the most biologically active isoflavones, we obtained four extracts from sprouts before and after their lactic fermentation and/or β-glucosidase treatment. Our previous results of ITC (isothermal titration calorimetry) modelling and a docking simulation showed clover isoflavones’ affinity to ERβ binding, which may downregulate cancer cell proliferation and migration. Thus, the biological activity of T. pratense sprouts’ extracts was checked under in vitro conditions against highly invasive human breast cancer cell line MDA-MB-231 and non-invasive human breast cancer cell line MCF-7 cells. To compare extracts’ activities acquired for cancer cells with those activities against normal cells, as a third model we choose human umbilical vein endothelial cells (HUVEC), which, due to their migration abilities, are involved in blood vessel formation. Extracts obtained from fermented sprouts at IC0 dosages were able to inhibit migration of breast cancer cells through their influence on intracellular ROS generation; membrane stiffening; adhesion; regulation of MMP-9, N-cadherin and E-cadherin at transcriptional level; or VEGF secretion. Simultaneously, isolated phenolics revealed no toxicity against normal HUVEC cells. In the manuscript, we proposed a preliminary mechanism accounting for the in vitro activity of Trifolium pratense L. isoflavones. In this manner, T. pratense sprouts, especially after their lactic fermentation, can be considered a potent source of biological active phytoestrogens and a dietary supplement with anti-cancer and anti-invasion properties.

3-Methylindole-substituted zinc phthalocyanines for photodynamic cancer therapy

Novel peripherally and non-peripherally 3-methylindole-substituted zinc phthalocyanine derivatives were synthesized as photosensitizers for photodynamic therapy in cancer treatment. The photophysical, photochemical and photobiological properties of targeted phthalocyanines were also investigated. For this purpose, the fluorescence and singlet oxygen quantum yields, and fluorescence lifetime values of the final compounds were determined in DMF solutions. The phototoxicity and cytotoxicity of the phthalocyanine complexes were tested against the invasive human breast cancer cell line (MDA-MB-231) for determination of their photosensitizing ability in the area of photodynamic therapy. It was revealed that while peripherally 3-methylindole-substituted phthalocyanine was found to be toxic for cells in both dark and light conditions, its non-peripherally substituted phthalocyanine analogue significantly caused cell death following light irradiation. A preliminary assay suggested that the non-peripherally linked phthalocyanine could be a suitable candidate for cancer treatment via photodynamic therapy techniques.

Differentiated impact of procyanidins from evening primrose on human breast cancer cells

This study examines some of the biological activities of an evening primrose flavanol preparation (EPFP) against non-invasive human breast cancer cells (MCF-7). The results are compared with those obtained for highly invasive human breast cancer cells (MDAMB-231). The results show, for the first time, that EPFP reduces MCF-7 cell number, IC50 = 75 µM gallic acid equivalents/GAE for 72 h incubation, and reduces migration to 52% of the control value at 100 µM L−1 GAE. EPFP caused favorable changes in Bcl-2/Bax mRNA ratio, which rendered MCF-7 cells more sensitive to apoptosis: the number of apoptotic cells increased 2.2-fold vs. control at 100 µM GAE. Furthermore, 100 µ M L−1 GAE EPFP caused a 1.8-fold reduction in the activity of metalloproteinase-9 (MMP-9) secreted to the culture medium by MCF-7 cells. Moreover, EPFP suppressed the expression of selected genes of matrix metalloproteinases (MMPs), a proliferation marker (Ki67), and vascular endothelial growth factor (VEGF). In conclusion, the results of this study suggest that EPFP may exhibit proapoptotic, antiproliferative, antimigratory, and antimetastatic potential towards both selected human breast cancer cell lines, which is more pronounced in the case of the highly invasive MDA-MB-231 cells.