SHOC2 is associated with the survival of breast cancer cells and has prognostic value for patients with breast cancer

SHOC2 mediates the drug-resistance of triple-negative breast cancer cells to everolimus

Aberrant activation of the mTOR pathway is a characteristic alteration in triple-negative breast cancer, but the mTOR pathway inhibitor everolimus is not effective for the triple-negative breast cancer (TNBC) patients. Presently, we showed that the activation of ERK pathway was an important mechanism of resistance to everolimus in TNBC cells in this study. SHOC2, a key protein mediating the Ras-Raf-ERK pathway, could act as a scaffolding protein to facilitate the activation of the pathway by mediating the interaction of key components of the pathway. Our results showed that everolimus activated the Raf-ERK pathway by promoting the interaction between SHOC2 and c-Raf and that knockdown of SHOC2 significantly inhibited the Raf-ERK pathway induced by everolimus. We further demonstrated that SHOC2 expression levels were closely related to the sensitivity of TNBC cells to everolimus and that interference with SHOC2 expression in combination with everolimus had significant effects on the cell cycle progression and apoptosis in vitro experiments. Western blotting analysis showed that cell cycle regulators and apoptosis-related proteins were significantly altered by the combination treatment. Xenograft model also demonstrated that knockdown of SHOC2 significantly increased the sensitivity of tumor to everolimus in nude mice. In conclusion, our study showed that SHOC2 is a key factor in regulating the sensitivity of TNBC cells to everolimus and that combined therapy may be a more effective therapeutic approach for TNBC patients.

Circular RNA in Acute Central Nervous System Injuries: A New Target for Therapeutic Intervention

Acute central nervous system (CNS) injuries, including ischemic stroke, traumatic brain injury (TBI), spinal cord injury (SCI) and subarachnoid hemorrhage (SAH), are the most common cause of death and disability around the world. As a kind of non-coding ribonucleic acids (RNAs) with endogenous and conserve, circular RNAs (circRNAs) have recently attracted great attentions due to their functions in diagnosis and treatment of many diseases. A large number of studies have suggested that circRNAs played an important role in brain development and involved in many neurological disorders, particularly in acute CNS injuries. It has been proposed that regulation of circRNAs could improve cognition function, promote angiogenesis, inhibit apoptosis, suppress inflammation, regulate autophagy and protect blood brain barrier (BBB) in acute CNS injuries via different molecules and pathways including microRNA (miRNA), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), ph1osphatidylinositol-4,5-bisphosphate 3-kinase/protein kinase B (PI3K/AKT), Notch1 and ten-eleven translocation (TET). Therefore, circRNAs showed great promise as potential targets in acute CNS injuries. In this article, we present a review highlighting the roles of circRNAs in acute CNS injuries. Hence, on the basis of these properties and effects, circRNAs may be developed as therapeutic agents for acute CNS injury patients.

NSUN2 modified by SUMO-2/3 promotes gastric cancer progression and regulates mRNA m5C methylation

The 5-methylcytosine (m5C) RNA methyltransferase NSUN2 is involved in the regulation of cell proliferation and metastasis formation and is upregulated in multiple cancers. However, the biological significance of NSUN2 in gastric cancer (GC) and the modification of NSUN2 itself have not been fully investigated. Here, we analyzed the expression level of NSUN2 in tissue microarrays containing 403 GC tissues by immunohistochemistry. NSUN2 was upregulated in GC, and that it was a predictor of poor prognosis. NSUN2 promotes the proliferation, migration, and invasion of GC cells in vitro. We also demonstrated that small ubiquitin-like modifier (SUMO)-2/3 interacts directly with NSUN2 by stabilizing it and mediating its nuclear transport. This facilitates the carcinogenic activity of NSUN2. Furthermore, m5C bisulfite sequencing (Bis-seq) in NSUN2-deficient GC cells showed that m5C-methylated genes are involved in multiple cancer-related signaling pathways. PIK3R1 and PCYT1A may be the target genes that participate in GC progression. Our findings revealed a novel mechanism by which NSUN2 functions in GC progression. This may provide new treatment options for GC patients.

Sequence Neighborhoods Enable Reliable Prediction of Pathogenic Mutations in Cancer Genomes

Simple Summary

Cancer is caused by the accumulation of somatic mutations, some of which are responsible for the disease’s progression (drivers) while others are functionally neutral (passengers). Although several methods have been developed to distinguish between the two classes of mutations, very few have concentrated on using the neighborhood nucleotide sequences as potential discrimination features. In this study, we show that driver mutations’ neighborhood is significantly different from that of passengers. We further develop a novel machine learning tool, NBDriver, which is highly efficient at identifying pathogenic variants from multiple independent test datasets. Efficient and accurate identification of novel pathogenic variants from sequenced cancer genomes would help facilitate more effective therapies tailored to patients’ mutational profiles.

Abstract

Identifying cancer-causing mutations from sequenced cancer genomes hold much promise for targeted therapy and precision medicine. “Driver” mutations are primarily responsible for cancer progression, while “passengers” are functionally neutral. Although several computational approaches have been developed for distinguishing between driver and passenger mutations, very few have concentrated on using the raw nucleotide sequences surrounding a particular mutation as potential features for building predictive models. Using experimentally validated cancer mutation data in this study, we explored various string-based feature representation techniques to incorporate information on the neighborhood bases immediately 5′ and 3′ from each mutated position. Density estimation methods showed significant distributional differences between the neighborhood bases surrounding driver and passenger mutations. Binary classification models derived using repeated cross-validation experiments provided comparable performances across all window sizes. Integrating sequence features derived from raw nucleotide sequences with other genomic, structural, and evolutionary features resulted in the development of a pan-cancer mutation effect prediction tool, NBDriver, which was highly efficient in identifying pathogenic variants from five independent validation datasets. An ensemble predictor obtained by combining the predictions from NBDriver with three other commonly used driver prediction tools (FATHMM (cancer), CONDEL, and MutationTaster) significantly outperformed existing pan-cancer models in prioritizing a literature-curated list of driver and passenger mutations. Using the list of true positive mutation predictions derived from NBDriver, we identified a list of 138 known driver genes with functional evidence from various sources. Overall, our study underscores the efficacy of using raw nucleotide sequences as features to distinguish between driver and passenger mutations from sequenced cancer genomes.

The leucine-rich repeat signaling scaffolds Shoc2 and Erbin: cellular mechanism and role in disease

Leucine-rich repeat-containing proteins (LRR proteins) are involved in supporting a large number of cellular functions. In this review, we summarize recent advancements in understanding functions of the LRR proteins as signaling scaffolds. In particular, we explore what we have learned about the mechanisms of action of the LRR scaffolds Shoc2 and Erbin and their roles in normal development and disease. We discuss Shoc2 and Erbin in the context of their multiple known interacting partners in various cellular processes and summarize often unexpected functions of these proteins through analysis of their roles in human pathologies. We also review these LRR scaffold proteins as promising therapeutic targets and biomarkers with potential application across various pathologies.