Cancer stem cells (CSCs) are subpopulations of tumor masses with unique abilities in self-renewal, stemness maintenance, drug resistance, and the promotion of cancer recurrence. Recent studies have suggested that breast CSCs play essential roles in chemoresistance. Therefore, new agents that selectively target such cells are urgently required. Reactive oxygen species (ROS)-producing enzymes are the reason for an elevated tumor oxidant status. The nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcriptional factor, which upon detecting cellular oxidative stress, binds to the promoter region of antioxidant genes. By triggering a cytoprotective response, Nrf2 maintains cellular redox status. Cripto-1 participates in the self-renewal of CSCs. Herein, luteolin, a flavonoid found in Taraxacumofficinale extract, was determined to inhibit the expressions of stemness-related transcriptional factors, the ATP-binding cassette transporter G2 (ABCG2), CD44, aldehyde dehydrogenase 1 activity as well as the sphere formation properties of breast CSCs. Furthermore, luteolin suppressed the protein expressions of Nrf2, heme oxygenase 1 (HO-1), and Cripto-1 which have been determined to contribute critically to CSC features. The combination of luteolin and the chemotherapeutic drug, Taxol, resulted in enhanced cytotoxicity to breast cancer cells. These findings suggest that luteolin treatment significantly attenuated the hallmarks of breast cancer stemness by downregulating Nrf2-mediated expressions. Luteolin constitutes a potential agent for use in cancer stemness-targeted breast cancer treatments.
Globally, the incidence rate for breast cancer ranks first. Treatment for early-stage breast cancer is highly cost effective. Five-year survival rate for stage 0–2 breast cancer exceeds 90%. Screening mammography has been acknowledged as the most reliable way to diagnose breast cancer at an early stage. Taiwan government has been urging women without any symptoms, aged between 45 and 69, to have a screening mammogram bi-yearly. This brings about a large workload for radiologists. In light of this, this paper presents a deep neural network (DNN)-based model as an efficient and reliable tool to assist radiologists with mammographic interpretation. For the first time in the literature, mammograms are completely classified into BI-RADS categories 0, 1, 2, 3, 4A, 4B, 4C and 5. The proposed model was trained using block-based images segmented from a mammogram dataset of our own. A block-based image was applied to the model as an input, and a BI-RADS category was predicted as an output. At the end of this paper, the outperformance of this work is demonstrated by an overall accuracy of 94.22%, an average sensitivity of 95.31%, an average specificity of 99.15% and an area under curve (AUC) of 0.9723. When applied to breast cancer screening for Asian women who are more likely to have dense breasts, this model is expected to give a higher accuracy than others in the literature, since it was trained using mammograms taken from Taiwanese women.
Although chemotherapy is the preferred treatment for gastric cancer, the therapeutic drugs currently available have limited efficacy and severe side effects. Cancer stem cells within tumor masses have the distinctive properties of self-renewal, maintenance, and resistance to chemotherapy. Hence, agents capable of targeting stemness in gastric tumors with minimal side effects are urgently required. Enzymes that generate reactive oxygen species contribute to the high oxidation levels observed in tumors. Additionally, nuclear factor erythroid 2-related factor 2 (Nrf2), an antioxidant transcription factor, regulates cancer stemness. Increasing evidence highlights the potential of nutritional supplementation to treat cancer stemness. ω-3 polyunsaturated fatty acids support human health and offer benefits for cancer treatment. Linolenic acid (LA), an ω-3 polyunsaturated fatty acid, inhibits the expression of proteins associated with stemness and promotes apoptosis in gastric cancer cells. Our findings indicated that LA treatment substantially inhibited key characteristics of gastric cancer stemness and induced oxidative stress and caspase-3-mediated apoptosis by downregulating Nrf2-mediated expression. These results suggest that LA is a promising nutritional supplement for targeting cancer stemness in the treatment of gastric cancer.
Glioblastoma (GBM) frequently recurs after temozolomide (TMZ) therapy and exhibits substantial redox plasticity. Our previous work showed that the effects of hydrogen peroxide (H2O2) vary with its level and between parental and TMZ-resistant GBM cells. Succinate dehydrogenase subunit D (SDHD), a membrane-anchoring component of mitochondrial complex II, is positioned at the interface of electron transport and redox homeostasis, but its regulation in GBM remains unclear. We therefore examined whether SDHD expression changes across distinct H2O2-responsive contexts involving aquaporins (AQPs) and AKT. TCGA transcriptomic analysis showed higher SDHD mRNA expression in WHO grade IV than in grade II/III gliomas, whereas paired primary/recurrent high-grade glioma samples showed heterogeneous SDHD changes at recurrence. TMZ reduced SDHD, and SDHD knockdown decreased intracellular reactive oxygen species. Combined redox perturbation reduced SDHD, whereas AKT inhibition restored SDHD expression. Under receptor-associated signaling conditions, EGFRvIII expression or CXCL12 stimulation increased measured H2O2 together with AQP3, AKT Ser473 phosphorylation, and SDHD. In TMZ-resistant cells, pharmacological perturbation of aquaporin-associated signaling decreased AQP9 together with AKT Ser473 phosphorylation and SDHD. An AQP3-targeting compound further reduced cell density when combined with TMZ. Together, these findings suggest that changes in SDHD expression are consistent with a compensatory redox response in GBM cells and that its regulation varies with the nature of H2O2-associated signaling during TMZ-related stress.
1 February 2019 in The Annals of The Royal College of Surgeons of England