High expression of SNIP1 correlates with poor prognosis in non-small cell lung cancer and SNIP1 interferes with the recruitment of HDAC1 to RB in vitro

The clinical utilization of SNIP1 and its pathophysiological mechanisms in disease

Smad intranuclear binding protein 1 (SNIP1), a highly conserved nuclear protein, functions as a transcriptional regulator and exerts a significant influence on disease progression. In addition, the N-terminal domain of SNIP1 facilitates its interaction with Smad4, a signaling protein associated with the TGF-β family, and RelA/p65, a transcription factor connected to NF-κB. This interaction further enhances the transcriptional activation of c-Myc-dependent genes. Presently, the primary emphasis in research is directed towards targeting the catalytic domain of SNIP1, as it holds promise as a potential therapeutic target for various diseases. While the significance of SNIP1 in pathological mechanisms remains uncertain, this review aims to comprehensively examine the existing literature on the association between SNIP1 and proteins implicated in the regulation of diverse clinical conditions, including cancer, inflammation, and related diseases.

SNIP1 and PRC2 coordinate cell fates of neural progenitors during brain development

Stem cell survival versus death is a developmentally programmed process essential for morphogenesis, sizing, and quality control of genome integrity and cell fates. Cell death is pervasive during development, but its programming is little known. Here, we report that Smad nuclear interacting protein 1 (SNIP1) promotes neural progenitor cell survival and neurogenesis and is, therefore, integral to brain development. The SNIP1-depleted brain exhibits dysplasia with robust induction of caspase 9-dependent apoptosis. Mechanistically, SNIP1 regulates target genes that promote cell survival and neurogenesis, and its activities are influenced by TGFβ and NFκB signaling pathways. Further, SNIP1 facilitates the genomic occupancy of Polycomb complex PRC2 and instructs H3K27me3 turnover at target genes. Depletion of PRC2 is sufficient to reduce apoptosis and brain dysplasia and to partially restore genetic programs in the SNIP1-depleted brain in vivo. These findings suggest a loci-specific regulation of PRC2 and H3K27 marks to toggle cell survival and death in the developing brain.

MiR-138-5p suppresses the progression of lung cancer by targeting SNIP1

BACKGROUND

MicroRNAs (miRNAs) play crucial roles in the development of various cancers. Here, we aimed to evaluate the roles of miR-138-5p in lung cancer progression and the value of miR-138-5p in lung cancer diagnosis.

METHODS

Quantitative real-time PCR was performed to examine the expressions of miR-138-5p and smad nuclear interacting protein 1 (SNIP1) mRNA. The diagnostic value of miR-138-5p was analyzed using receiver operating characteristic (ROC) curve analysis, sensitivity, and specificity. We explored the effect of miR-138-5p on cell proliferation and metastasis by CCK-8, colony formation, wound healing and transwell assays. Western blot was employed to detect the protein expression of SNIP1 and related genes. Lung cancer cell growth was evaluated in vivo using xenograft tumor assay.

RESULTS

MiR-138-5p was decreased in the serum of patients with non-small cell lung cancer (NSCLC) and in NSCLC cells and tissues. The area under the ROC curve of serum miR-138-5p in the diagnosis of NSCLC was 0.922. This finding indicates the high diagnostic efficiency for lung cancer. MiR-138-5p suppressed but its inhibitor promoted cell proliferation and migration compared with control treatment in vitro and in vivo. MiR-138-5p directly binds to the 3'-untranslated region of SNIP1 and negatively regulated the expression of SNIP1, thereby inhibiting the expression of cyclin D1 and c-Myc. Moreover, overexpression of SNIP1 rescues the miR-138-5p-mediated inhibition in NSCLC cells.

CONCLUSIONS

The results suggested that miR-138-5p suppressed lung cancer cell proliferation and migration by targeting SNIP1. Serum miR-138-5p is a novel and valuable biomarker for NSCLC diagnosis.

Development and Validation of a Prognostic Model of RNA-Binding Proteins in Colon Adenocarcinoma: A Study Based on TCGA and GEO Databases

Background

Previous studies reported that dysregulation of RNA-binding proteins (RBPs) is significantly associated with the development of cancer. However, there are few studies to date on the role of RBPs in colon adenocarcinoma (COAD).

Methods

RNA sequencing and clinical data for COAD patients were downloaded from The Cancer Genome Atlas (TCGA) database to identify differentially expressed (DE) RBPs between COAD tissue and normal colon tissue, and then the expression and prognostic significance of these RBPs were investigated in detail by systematic bioinformatics analysis. qRT-PCR was used to validate the expressions of prognosis-related RBP-encoding genes.

Results

Seven RBPs (RPL10L, ERI1, POP1, CAPRIN2, TDRD7, SNIP1 and PPARGC1A) were identified as hub genes associated with prognosis by a series of regression analyses, and were then used to construct a prognostic model. Further analysis based on this model indicated that the overall survival (OS) of the high-risk groups was lower than that of the low-risk groups. In this prognostic model, the area under the ROC curve (AUC) was 0.694, 0.709 and 0.665 for the TCGA cohort at 1, 3 and 5 years, respectively, while the AUC was 0.671, 0.633 and 0.601 for the GEO combined cohort at 1, 3 and 5 years, respectively, indicating the good predictive ability of the model. We also built a nomogram based on the 7 RBPs in the TCGA cohort, and the model showed good discriminatory ability for COAD.

Conclusion

We screened seven prognosis-related genes in COAD patients based on RBP-related genes, validated the expressions of the seven prognosis-related RBP-encoding genes by qRT-PCR and constructed a prognosis-related nomogram for patients with COAD.

Long non-coding RNA AFAP1-AS1 accelerates lung cancer cells migration and invasion by interacting with SNIP1 to upregulate c-Myc

Actin filament associated protein 1 antisense RNA 1 (named AFAP1-AS1) is a long non-coding RNA and overexpressed in many cancers. This study aimed to identify the role and mechanism of AFAP1-AS1 in lung cancer. The AFAP1-AS1 expression was firstly assessed in 187 paraffin-embedded lung cancer and 36 normal lung epithelial tissues by in situ hybridization. The migration and invasion abilities of AFAP1-AS1 were investigated in lung cancer cells. To uncover the molecular mechanism about AFAP1-AS1 function in lung cancer, we screened proteins that interact with AFAP1-AS1 by RNA pull down and the mass spectrometry analyses. AFAP1-AS1 was highly expressed in lung cancer clinical tissues and its expression was positively correlated with lung cancer patients’ poor prognosis. In vivo experiments confirmed that AFAP1-AS1 could promote lung cancer metastasis. AFAP1-AS1 promoted lung cancer cells migration and invasion through interacting with Smad nuclear interacting protein 1 (named SNIP1), which inhibited ubiquitination and degradation of c-Myc protein. Upregulation of c-Myc molecule in turn promoted the expression of ZEB1, ZEB2, and SNAIL gene, which ultimately enhanced epithelial to mesenchymal transition (EMT) and lung cancer metastasis. Understanding the molecular mechanism by which AFAP1-AS1 promotes lung cancer’s migration and invasion may provide novel therapeutic targets for lung cancer patients’ early diagnosis and therapy.

miR-29a-3p directly targets Smad nuclear interacting protein 1 and inhibits the migration and proliferation of cervical cancer HeLa cells

Smad nuclear interacting protein 1 (SNIP1) is a nuclear protein and involved in essential biological processes. MicroRNAs are effective regulators of tumorigenesis and cancer progression via targeting multiple genes. In present study, we aimed to investigate the function of SNIP1 and identify novel miRNA-SNIP1 axis in the development of cervical cancer. The results showed for the first time that silencing of the SNIP1 gene inhibited the migration and proliferation in HeLa cells significantly. Bioinformatics analysis and dual luciferase reporter assay demonstrated that miR-29a-3p could target 3' UTR of SNIP1 directly. The mRNA and protein expression levels of SNIP1 were negative regulated by miR-29a-3p according to the RT-qPCR and Western blot analysis, respectively. Furthermore, functional studies showed that over-expression of miR-29a-3p restrained HeLa cells migration and proliferation, and the mRNA expression of SNIP1 downstream genes (HSP27, c-Myc, and cyclin D1) were down-regulated by miR-29a-3p. Together, we concluded that miR-29a-3p suppressed the migration and proliferation in HeLa cells by directly targeting SNIP1. The newly identified miR-29a-3p/SNIP1 axis could provide new insight into the development of cervical cancer.

Lentivirus-mediated Knockdown of HDAC1 Uncovers Its Role in Esophageal Cancer Metastasis and Chemosensitivity

Histone deacetylationase 1 (HDAC1) is ubiquitously expressed in various cell lines and tissues and play an important role of regulation gene expression. Overexpression of HDAC1 has been observed in various types of cancers, which indicated that it might be a target for cancer therapy. To test HDAC1 inhibition for cancer treatment, the gene expression of HDAC1 was knockdown mediated by a lentivirus system. Our data showed the gene expression of HDAC1 could be efficiently knockdown by RNAi mediated by lentivirus in esophageal carcinoma EC109 cells. Knockdown of HDAC1 led to significant decrease of cell growth and altered cell cycle distribution. The result of transwell assay showed that the numbers of cells travelled through the micropore membrane was significantly decreased as HDAC1 expression was knockdown. Moreover, HDAC1 knockdown inhibited the migration of EC109 cells as determining by scratch test. Additionally, enhancement of cisplatin-stimulated apoptosis was detected by HDAC1 knockdown. Our data suggested inhibition of HDAC1 expression by lentivirus mediated shRNA might be further applied for esophageal cancer chemotherapy.