DDX3 depletion represses translation of mRNAs with complex 5' UTRs.

DDX3 is an RNA chaperone of the DEAD-box family that regulates translation. Ded1, the yeast ortholog of DDX3, is a global regulator of translation, whereas DDX3 is thought to preferentially affect a subset of mRNAs. However, the set of mRNAs that are regulated by DDX3 are unknown, along with the relationship between DDX3 binding and activity. Here, we use ribosome profiling, RNA-seq, and PAR-CLIP to define the set of mRNAs that are regulated by DDX3 in human cells. We find that while DDX3 binds highly expressed mRNAs, depletion of DDX3 particularly affects the translation of a small subset of the transcriptome. We further find that DDX3 binds a site on helix 16 of the human ribosomal rRNA, placing it immediately adjacent to the mRNA entry channel. Translation changes caused by depleting DDX3 levels or expressing an inactive point mutation are different, consistent with different association of these genetic variant types with disease. Taken together, this work defines the subset of the transcriptome that is responsive to DDX3 inhibition, with relevance for basic biology and disease states where DDX3 is altered.

Tamoxifen Modulates the Immune Landscape of the Tumour Microenvironment: The Paired Siglec-5/14 Checkpoint in Anti-Tumour Immunity in an In Vitro Model of Breast Cancer.

Since the role of sialome-Siglec axis has been described as a regulatory checkpoint of immune homeostasis, the promotion of stimulatory or inhibitory Siglec-related mechanisms is crucial in cancer progression and therapy. Here, we investigated the effect of tamoxifen on the sialic acid-Siglec interplay and its significance in immune conversion in breast cancer. To mimic the tumour microenvironment, we used oestrogen-dependent or oestrogen-independent breast cancer cells/THP-1 monocytes transwell co-cultures exposed to tamoxifen and/or ß-estradiol. We found changes in the cytokine profiles accompanied by immune phenotype switching, as measured by the expression of arginase-1. The immunomodulatory effects of tamoxifen in THP-1 cells occurred with the altered SIGLEC5 and SIGLEC14 genes and the expression of their products, as confirmed by RT-PCR and flow cytometry. Additionally, exposure to tamoxifen increased the binding of Siglec-5 and Siglec-14 fusion proteins to breast cancer cells; however, these effects appeared to be unassociated with oestrogen dependency. Our results suggest that tamoxifen-induced alterations in the immune activity of breast cancer reflect a crosstalk between the Siglec-expressing cells and the tumour's sialome. Given the distribution of Siglec-5/14, the expression profile of inhibitory and activatory Siglecs in breast cancer patients may be useful in the verification of therapeutic strategies and predicting the tumour's behaviour and the patient's overall survival.

Health-Related Quality of Life After Nipple-Sparing Mastectomy: Results From the INSPIRE Registry.

INTRODUCTION: Nipple-sparing mastectomy (NSM) with immediate breast reconstruction (IBR) is increasingly used for both breast cancer (TNSM) and risk reduction (RRNSM). The aim of the study is to report the results of the INSPIRE registry assessing health-related quality of life (HRQoL) comparing baseline and 1-year follow-up, regarding surgical indications and chemotherapy (CT) received. METHODS: INSPIRE is a prospective database including women undergoing NSM and IBR from 18 countries. HRQoL was measured using EORTC QLQC30 and QLQ-BR23 before surgery and after 1 year. RESULTS: A total of 677 women were included, of whom 537 (79.3%) underwent TNSM and 140 (21.6%) RRNSM: in total, 806 NSM (556 TNSM and 250 RRNSM). Nipple involvement was present in 7.73% of TNSM and incidental carcinoma in 1.2% of the RRNSM group. Out of the overall 537 patients with systemic treatment, 177 (32.96%) received neoadjuvant chemotherapy (NCT) and 118 (21.92%) adjuvant chemotherapy (CT). A total of 227 patients (28.16%) developed at least one complication postoperatively, 164 (29.5%) in the TNSM group and 63 (25.2%) in the RRNSM group. The TNSM group improved in global health status and emotional functioning after 1 year. No differences were found when comparing HRQoL at 1 year between patients who received NCT and those who received adjuvant CT. The RRNSM group showed improvement in HRQoL, with better emotional functioning and fatigue after 1 year. CONCLUSIONS: This registry reports HRQoL findings after NSM. The impact of CT on worse HRQoL is independent from its timing. Patients with RRNSM showed an improved HRQoL at 1-year follow-up. Discussion of HRQoL outcomes with patients will facilitate the informed decision-making when considering NSM.

The Paired Siglecs in Brain Tumours Therapy: The Immunomodulatory Effect of Dexamethasone and Temozolomide in Human Glioma In Vitro Model.

The paired sialic acid-binding immunoglobulin like lectins (Siglecs) are characterized by similar cellular distribution and ligand recognition but opposing signalling functions attributed to different intracellular sequences. Since sialic acid-Siglec axis are known to control immune homeostasis, the imbalance between activatory and inhibitory mechanisms of glycan-dependent immune control is considered to promote pathology. The role of sialylation in cancer is described, however, its importance in immune regulation in gliomas is not fully understood. The experimental and clinical observation suggest that dexamethasone (Dex) and temozolomide (TMZ), used in the glioma management, alter the immunity within the tumour microenvironment. Using glioma-microglia/monocytes transwell co-cultures, we investigated modulatory action of Dex/TMZ on paired Siglecs. Based on real-time PCR and flow cytometry, we found changes in SIGLEC genes and their products. These effects were accompanied by altered cytokine profile and immune cells phenotype switching measured by arginases expression. Additionally, the exposure to Dex or TMZ increased the binding of inhibitory Siglec-5 and Siglec-11 fusion proteins to glioma cells. Our study suggests that the therapy-induced modulation of the interplay between sialoglycans and paired Siglecs, dependently on patient's phenotype, is of particular signification in the immune surveillance in the glioma management and may be useful in glioma patient's therapy plan verification.

Sialic Acid-Siglec Axis as Molecular Checkpoints Targeting of Immune System: Smart Players in Pathology and Conventional Therapy.

The sialic acid-based molecular mimicry in pathogens and malignant cells is a regulatory mechanism that leads to cross-reactivity with host antigens resulting in suppression and tolerance in the immune system. The interplay between sialoglycans and immunoregulatory Siglec receptors promotes foreign antigens hiding and immunosurveillance impairment. Therefore, molecular targeting of immune checkpoints, including sialic acid-Siglec axis, is a promising new field of inflammatory disorders and cancer therapy. However, the conventional drugs used in regular management can interfere with glycome machinery and exert a divergent effect on immune controlling systems. Here, we focus on the known effects of standard therapies on the sialoglycan-Siglec checkpoint and their importance in diagnosis, prediction, and clinical outcomes.

Unexpectedly rapid IS1 transposition into an Arabidopsis chromatin remodeling gene.

Common cloning is often associated with instability of certain classes of DNA. Here we report on IS1 transposition as possible source of such instability. During the cloning of Arabidopsis thaliana gene into commercially available vector maintained in widely used Escherichia coli host the insertion of complete IS1 element into the intron of cloned gene was found. The transposition of the IS1 element was remarkably rapid and is likely to be sequence-specific. The use of E. coli strains that lower the copy number of vector or avoiding the presence of the problematic sequence is a solution to the inadvertent transposition of IS1. The transposition of IS1 is rare but it can occur and might confound functional studies of a plant gene.

Coronaviruses: Is Sialic Acid a Gate to the Eye of Cytokine Storm? From the Entry to the Effects.

Coronaviruses (CoVs) are a diverse family of the enveloped human and animal viruses reported as causative agents for respiratory and intestinal infections. The high pathogenic potential of human CoVs, including SARS-CoV, MERS-CoV and SARS-CoV-2, is closely related to the invasion mechanisms underlying the attachment and entry of viral particles to the host cells. There is increasing evidence that sialylated compounds of cellular glycocalyx can serve as an important factor in the mechanism of CoVs infection. Additionally, the sialic acid-mediated cross-reactivity with the host immune lectins is known to exert the immune response of different intensity in selected pathological stages. Here, we focus on the last findings in the field of glycobiology in the context of the role of sialic acid in tissue tropism, viral entry kinetics and immune regulation in the CoVs infections.