Synemin: an evolving role in tumor growth and progression

A risk model of gene signatures for predicting platinum response and survival in ovarian cancer

Background

Ovarian cancer (OC) is the deadliest tumor in the female reproductive tract. And increased resistance to platinum-based chemotherapy represents the major obstacle in the treatment of OC currently. Robust and accurate gene expression models are crucial tools in distinguishing platinum therapy response and evaluating the prognosis of OC patients.

Methods

In this study, 230 samples from The Cancer Genome Atlas (TCGA) OV dataset were subjected to mRNA expression profiling, single nucleotide polymorphism (SNP), and copy number variation (CNV) analysis comprehensively to screen out the differentially expressed genes (DEGs). An SVM classifier and a prognostic model were constructed using the Random Forest algorithm and LASSO Cox regression model respectively via R. The Gene Expression Omnibus (GEO) database was applied as the validation set.

Results

Forty-eight differentially expressed genes (DEGs) were figured out through integrated analysis of gene expression, single nucleotide polymorphism (SNP), and copy number variation (CNV) data. A 10-gene classifier was constructed which could discriminate platinum-sensitive samples precisely with an AUC of 0.971 in the training set and of 0.926 in the GEO dataset (GSE638855). In addition, 8 optimal genes were further selected to construct the prognostic risk model whose predictions were consistent with the actual survival outcomes in the training cohort (p = 9.613e-05) and validated in GSE638855 (p = 0.04862). PNLDC1, SLC5A1, and SYNM were then identified as hub genes that were associated with both platinum response status and prognosis, which was further validated by the Fudan University Shanghai cancer center (FUSCC) cohort.

Conclusion

These findings reveal a specific risk model that could serve as effective biomarkers to identify patients’ platinum response status and predict survival outcomes for OC patients. PNLDC1, SLC5A1, and SYNM are the hub genes that may serve as potential biomarkers in OC treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-022-00969-3.

Determination of distinctive hypomethylated genes in African American colorectal neoplastic lesions

BACKGROUND

Few studies have analyzed progressive demethylation in the path to cancer. This is of utmost importance, especially in populations such as African Americans, who display aggressive tumors at diagnosis, and for whom markers of early neoplastic transformation are needed. Here, we determined hypomethylated targets in the path to colorectal cancer (CRC) using Reduced Representation Bisulfite Sequencing (RRBS).

METHODS

DNA was extracted from fresh frozen tissues of patients with different colon lesions (normal, tubular adenoma, tubulovillous adenoma, and five cancers). RRBS was performed on these DNA extracts to identify hypomethylated gene targets. Alignment, mapping, and methylation analyses were performed. Pathways affected by the hypomethylated gene targets were determined using Ingenuity Pathway Analysis (IPA).

RESULTS

Pairwise analyses of samples led to the identification of the following novel hypomethylated genes: ELMO3 (Engulfment and cell motility 3), SLC6A2 (Solute carrier family 6 member 2), SYNM (Synemin), and HMX2 (Homeobox 2). The ELMO3 promoter was significantly hypomethylated at five CpG sites, SYNM at two CpG sites, SLC6A2 at one CpG site, and the HMX2 gene at one CpG site. IPA placed these genes within important carcinogenic pathways.

CONCLUSIONS

This work provides insight into the role of hypomethylation in colon carcinogenesis in African Americans. The identified targets affected many important pathways, as demonstrated through IPA. These targets might serve as biomarkers for early diagnosis and potential targets for therapy.

Synemin-related skeletal and cardiac myopathies: an overview of pathogenic variants

This review analyzes data concerning patients with cardiomyopathies or skeletal myopathies associated with a variation in the intermediate filament (IF) synemin gene (SYNM), also referred to as desmuslin (DMN). Molecular studies demonstrate that synemin copolymerizes with desmin and vimentin IF and interacts with vinculin, α-actinin, α-dystrobrevin, dystrophin, talin, and zyxin. It has been found that synemin is an A-kinase-anchoring protein (AKAP) that anchors protein kinase A (PKA) and modulates the PKA-dependent phosphorylation of several cytoskeletal substrates such as desmin. Because several IF proteins, including desmin, have been implicated in human genetic disorders such as dominant or recessive congenital and adult-onset myopathy, synemin becomes a significant candidate for cardiac and skeletal myopathies of unknown etiology. Because SYNM is a new candidate gene that displays numerous sequence polymorphisms, in this review, we summarize the genetic and clinical literature about SYNM mutations. Protein-changing variants (missense, frameshifts, nonsense) were further evaluated based on structural modifications and amino acid interactions. We present in silico modeling of helical salt-bridges between residues to evaluate the impact of the synemin networks crucial to interactions with cytoskeletal proteins. Finally, a discussion is featured regarding certain variants that may contribute to the disease state.