MicroRNAs (miRNAs) are a class of evolutionarily conserved, small non-coding RNAs of 19-24 nucleotides in length that regulate gene expression mostly at the posttranscriptional level. They are known to be involved in the control of different processes such as cell cycling, programmed cell death, cell differentiation, tumor development, metastasis, and sensing of nutrient stress. This review summarizes the evidence regarding the changes in miRNA expression that are caused by diets with a deficiency or augmented intake of nutrients such as amino acids, carbohydrates, fatty acids, vitamins, and phytochemicals. As diet is known to influence the expression of miRNAs, miRNA profiling has the potential to be useful in the assessment of nutritional status in dietary intervention studies. Additionally, as it can change miRNA expression, diet may be used as a therapeutic agent to treat many different diseases. Also, we explored here some ideas on therapeutics based on the manipulation of miRNA expression levels for dietary-derived diseases as well as the putative effect of food-derived miRNAs on host gene expression.

MicroRNAs (miRNAs) are non-coding RNAs of ~22 nucleotides in length that regulate gene expression by interfering with the stability and translation of mRNAs. Their expression is regulated during development, under a wide variety of stress conditions and in several pathological processes. In nature, animals often face feast or famine conditions. We observed that subjecting early L4 larvae from Caenorhabditis elegans to a 12-hr starvation period produced worms that are thinner and shorter than well-fed animals, with a decreased lipid accumulation, diminished progeny, reduced gonad size, and an increased lifespan. Our objective was to identify which of the 302 known miRNAs of C. elegans changed their expression under starvation conditions as compared to well-fed worms by means of deep sequencing in early L4 larvae. Our results indicate that 13 miRNAs (miR-34-3p, the family of miR-35-3p to miR-41-3p, miR-39-5p, miR-41-5p, miR-240-5p, miR-246-3p and miR-4813-5p) were upregulated, while 2 miRNAs (let-7-3p and miR-85-5p) were downregulated in 12-hr starved vs. well-fed early L4 larvae. Some of the predicted targets of the miRNAs that changed their expression in starvation conditions are involved in metabolic or developmental process. In particular, miRNAs of the miR-35 family were upregulated 6–20 fold upon starvation. Additionally, we showed that the expression of gld-1, important in oogenesis, a validated target of miR-35-3p, was downregulated when the expression of miR-35-3p was upregulated. The expression of another reported target, the cell cycle regulator lin-23, was unchanged during starvation. This study represents a starting point for a more comprehensive understanding of the role of miRNAs during starvation in C. elegans.

Background: Rare malignant tumors (RMT) make up 10% of all cancer in the pediatric age. The national and international cooperative projects will allow to understand their biology and improve the treatment results, making imperative the acknowledge the clinical course and the prognosis of Mexican pediatric patients with (RMT) Results: 178 patients were evaluated, with the age of 3 months to 17 years, 58% adolescents. The symptomatic presentation lag time was 7 days to 2 years. Most frequent symptoms were pain and palpable mass. The predominant histological type was thyroid carcinoma (29%) followed by 9% non-germ gonadal tumors and pancreatic exocrine tumors (6%). 27% metastatic. The treatment was surgical in 88%of the cases, and 5% received only palliative care. There were 38 patients with progression and 12 were due to toxicity. 18.9% of patients were lost of follow up due to abandonment of hospital care or transfer to adult hospital. Overall survival (OS) for all RMT was 63% at 100 months. SG for thyroid carcinomas was 68% within 109 months. Conclusion:The systematic study of RMT is not possible. Patients are staged and treated with protocols designed for adults. In our series, surgery is the cornerstone of treatment. Age establishes an organizational barrier for the treatment and follow-up of these patients in our country. Nevertheless we have taken the first step for this challenge in our country by assembling the first cooperative group of rare tumors, which hopes to become a support in the clinical decisions of pediatric oncologists in Mexico.