Over the years, nutrition and environmental factors have been demonstrated to influence human health, specifically cancer. Owing to the fact that cancer is a leading cause of death worldwide, efforts are being made to elucidate molecular mechanisms that trigger or delay carcinogenesis. Phytochemicals, in particular, have been shown to modulate oncogenic processes through their antioxidant and anti-inflammatory activities and their ability to mimic the chemical structure and activity of hormones. These compounds can act not only by influencing oncogenic proteins, but also by modulating noncoding RNAs such as microRNAs and long noncoding RNAs. Although we are only beginning to understand the complete effects of many natural compounds, such as phytochemicals, researchers are motivated to combine these agents with traditional, chemo-based, or hormone-based therapies to fight against cancer. Since ongoing studies continue to prove effective, herein we exalt the importance of improving dietary choices as a chemo-preventive strategy.
1 December 2015 in Journal of Gastrointestinal and Liver Diseases
Background: Worldwide, colorectal cancer (CRC) is the third most common cancer in men and second in women. The aim of the current study was to identify whether the miR-375 is indeed down-regulated in metastatic CRC and if it could be considered as a potential minimally invasive prognostic biomarker for CRC. Methods. Exosomes were isolated and characterized from patients with liver metastasis from CCR. The characterization of exosome was performed using TEM/SEM. HCT116 cells were treated with miR-375 mimic, NSM and miR-375 inhibitor. Functional assays included cell counting assay for 14 days, Matrigel invasion assay, apoptosis assay by flow cytometry using Annexin V-FITC, RT-PCR and Western blotting. Results. Increased proliferation potential was proven for the cells transfected with miR-375 inhibitor, while the miR-375 mimic decreased the cell number. The cells transfected with the miR-375 inhibitor are aggressive and cross the membrane; 3.84% of the cells transfected with the miR-375 inhibitor entered apoptosis, while 6.45% of those transfected with the non-specific mimic were in programmed cell death, less than those transfected with the microRNA. RT-PCR for Bcl-2 expression showed that Bcl-2 is down-regulated for miR-375 inhibitor and up-regulated for the miR-375 mimic, a result confirmed by Western blotting. Conclusion: The present study brings to the forefront new data that suggest miR-375 as a new player in controlling the pathways responsible for inhibiting the natural history of CRC tumor cells, via the Bcl-2 pathway. Abbreviations: APC: adenomatous polyposis coli; CRC: colorectal cancer; EGFR: epidermal growth factor receptor; ERB: Erythroblastic Leukemia Viral Oncogene Homolog; FITC: Fluorescein isothiocyanate; MAPK: mitogen-activated protein-kinase; miR: microRNA; mTOR: mammalian target of rapamycin; NSM: non specific mimic; qRT-PCR: quantitative real time polymerase chain reaction; SEM: scanning electron microscopy; TEM: transmission electron microscopy; TGF-beta: transforming growth factor beta.
EMT represents the dominant program within advanced stages of colon cancer, where cells acquire migratory characteristics in order to invade secondary tissues and form metastasis. Where the majority of the therapeutic strategies are concentrated on the reduction of the tumor mass through different apoptotic mechanisms, the present study advocates an important role for miR-205-5p in impairment of colon cancer cells migration and restoration of the epithelial phenotype. Upon identification of a homogenous downregulated profile for miR-205-5p in colon adenocarcinoma patients, functional studies demonstrated that experimental upregulation of this sequence is able to significantly raise the levels of E-cadherin through direct inhibition of ZEB1. Moreover, the elevation in CDH1 expression was translated into functional parameters where cells lost their invasion and migratory characteristics and formed homogenous clusters through adhesion interactions. Survival analysis of colon adenocarcinoma patients revealed that low levels of miR-205-5p are associated with an unfavorable prognostic compared to those with increased expression, demonstrating the possible clinical utility of miR-205-5p replacement. Exogenous administration of miRNA mimics was not associated with significant changes in cell viability or inflammatory pathways. Therefore, the proposed strategy is aiming towards inhibition of metastasis and limitation of the tumor borders in advanced stages patients in order to prolong the survival time and to increase the efficiency of the current therapeutic strategies.
MicroRNAs or miRNAs are small non-coding RNAs that regulate gene expression. Their discovery has brought new knowledge in biological processes of cancer. Involvement of miRNAs in cancer development includes several major pathways from cell transformation to tumor cell development, metastasis and resistance to treatment. The first part of this review discusses miRNAs function in the intrinsic and extrinsic pathways of apoptosis. Due to the fact that many miRNAs that regulate apoptosis have been shown to play a major role in tumor cell resistance to treatment, in the second part of the review we aim at discussing miRNAs potential in becoming curative molecules.
Background: Phytochemicals are natural compounds synthesized as secondary metabolites in plants and represent an important source of molecules with therapeutic applications. Attention is accorded to their potential in anti-cancer therapies as single agents or adjuvant treatment. Herby, we evaluated the in vitro effects of a panel of natural compounds with focus on caffeic acid phenethyl ester (CAPE) and Kaempferol for the treatment of human colon cancer. Methods: We exposed two human colon cancer cell lines, RKO and HCT-116, followed by functional examination of cell viability, cell proliferation and invasion, cell cycle, apoptosis, and autophagy. Modifications in gene expression were investigated through microarray and detection of existing mutations and finding of new ones was done with the help of Next Generation Sequencing (NGS). Results: Both CAPE and Kaempferol inhibit cell proliferation, motility and invasion, and stimulate apoptosis and autophagy, concomitant with modifications in coding and noncoding genes’ expression. Moreover, there are pathogenic mutations that are no longer found upon treatment with CAPE and Kaempferol. Conclusions: Our findings indicate that CAPE and Kaempferol have the ability to negatively influence the development and advancement of colon cancer in vitro by specifically altering the cells at the molecular level; this activity can be exploited in possible adjuvant therapies once the optimal dose concentration with minimal side effects but with cancer inhibitory activity is set in vivo.
The mortality and morbidity that characterize bladder cancer compel this malignancy into the category of hot topics in terms of biomolecular research. Therefore, a better knowledge of the specific molecular mechanisms that underlie the development and progression of bladder cancer is demanded. Tumor heterogeneity among patients with similar diagnosis, as well as intratumor heterogeneity, generates difficulties in terms of targeted therapy. Furthermore, late diagnosis represents an ongoing issue, significantly reducing the response to therapy and, inevitably, the overall survival. The role of non-coding RNAs in bladder cancer emerged in the last decade, revealing that microRNAs (miRNAs) may act as tumor suppressor genes, respectively oncogenes, but also as biomarkers for early diagnosis. Regarding other types of non-coding RNAs, especially long non-coding RNAs (lncRNAs) which are extensively reviewed in this article, their exact roles in tumorigenesis are—for the time being—not as evident as in the case of miRNAs, but, still, clearly suggested. Therefore, this review covers the non-coding RNA expression profile of bladder cancer patients and their validated target genes in bladder cancer cell lines, with repercussions on processes such as proliferation, invasiveness, apoptosis, cell cycle arrest, and other molecular pathways which are specific for the malignant transformation of cells.