SEA and GATOR 10 Years Later.

The SEA complex was described for the first time in yeast Saccharomyces cerevisiae ten years ago, and its human homologue GATOR complex two years later. During the past decade, many advances on the SEA/GATOR biology in different organisms have been made that allowed its role as an essential upstream regulator of the mTORC1 pathway to be defined. In this review, we describe these advances in relation to the identification of multiple functions of the SEA/GATOR complex in nutrient response and beyond and highlight the consequence of GATOR mutations in cancer and neurodegenerative diseases.

MicroRNA-125 modulates radioresistance through targeting p21 in cervical cancer.

Cervical cancer (CC) is one of the most common cancers diagnosed in women worldwide, and it is estimated that ~500,000 new patients are diagnosed with cervical cancer annually and that ~270,000 deaths occur each year. Patients with cervical cancer are treated with different radiotherapy schedules, either alone or with adjuvant chemotherapy. Unfortunately, nearly 50% of all patients with cervical cancer do not respond to standard treatment due to tumor radioresistance. In this scenario, several microRNAs (miRNAs) have been associated with the acquisition of the radioresistance phenotype. The aim of the present study was to evaluate the possible role of miR­125a in the acquisition of radioresistance in cervical cancer. The expression of miR­125a was assessed by means of RT­qPCR in 30 cervical cancer samples from patients receiving standard treatment and 3 induced radioresistant cervical cancer cell lines. In addition, we employed miR­125a mimics and inhibitors to evaluate its function in the induction of radioresistance. We showed that miR­125a was downregulated in patients with cervical cancer who did not respond to standard treatment. Concordantly, radioresistant SiHa, CaSki and HeLa cell lines had low levels of miR­125a with respect to the sensitive cell lines. Finally, we demonstrated that overexpression of miR­125a sensitized cervical cancer cells to radiation therapy through the downregulation of CDKN1A. Our data corroborate previously published studies in which it was demonstrated that miRNAs could play a role in the regulation of the process of radioresistance. Additionally, we showed that overexpression of miR­125a could be used as a radioresistance biomarker in patients with cervical cancer.

Monosodium urate crystals induce oxidative stress in human synoviocytes.

BACKGROUND: Gout is the most common inflammatory arthropathy of metabolic origin and it is characterized by intense inflammation, the underlying mechanisms of which are unknown. The aim of this study was to evaluate the oxidative stress in human fibroblast-like synoviocytes (FLS) exposed to monosodium urate (MSU) crystals, which trigger an inflammatory process. METHODS: Human FLS isolated from synovial tissue explants were stimulated with MSU crystals (75 µg/mL) for 24 h. Cellular viability was evaluated by crystal violet staining, apoptosis was assessed using Annexin V, and the cellular content of reactive oxygen species (ROS) and nitrogen species (RNS) (O2 (-), H2O2, NO) was assessed with image-based cytometry and fluorometric methods. In order to determine protein oxidation levels, protein carbonyls were detected through oxyblot analysis, and cell ultrastructural changes were assessed by transmission electron microscopy. RESULTS: The viability of FLS exposed to MSU crystals decreased by 30 % (P < 0.05), while apoptosis increased by 42 % (P = 0.01). FLS stimulated with MSU crystals exhibited a 2.1-fold increase in H2O2 content and a 1.5-fold increase in O2 (-) and NO levels. Oxyblots revealed that the spots obtained from FLS protein lysates exposed to MSU crystals exhibited protein carbonyl immunoreactivity, which reflects the presence of oxidatively modified proteins. Concomitantly, MSU crystals triggered the induction of changes in the morphostructure of FLS, such as the thickening and discontinuity of the endoplasmic reticulum, and the formation of vacuoles and misfolded glycoproteins. CONCLUSIONS: Our results prove that MSU crystals induce the release of ROS and RNS in FLS, subsequently oxidizing proteins and altering the cellular oxidative state of the endoplasmic reticulum, which results in FLS apoptosis.