Integrative Methylome and Transcriptome Characterization Identifies SERINC2 as a Tumor-Driven Gene for Papillary Thyroid Carcinoma

SERINC2-mediated serine metabolism promotes cervical cancer progression and drives T cell exhaustion

Cervical cancer remains the most prevalent gynecological malignant disease. Reprogramming tumor immune metabolism stands out as a novel promising therapeutic target. Here, we identified serine incorporator 2 (SERINC2) as a critical gene which highly expressed in cervical cancer and negatively correlated with clinical outcomes. Through functional assays, SERINC2 was determined to play a pro-tumoral role both in vivo and in vitro. Besides, the growth of cervical cancer cells was found to be largely dependent on serine in a manner influenced by SERINC2. As a serine transport associated protein, SERINC2 knockdown significantly reduced cervical cancer cells' intracellular serine level and altered the serine-associated-lipid metabolism. Immune infiltration analysis revealed that SERINC2 was negatively associated with CD8+ T cell infiltration and function. More importantly, we demonstrated a competitive relation between cancer cells and immune cells brought about by SERINC2. Mechanistically, cancer cells SERINC2 preferentially competed for micro-environmental serine over CD8+ T cells and rendered T cell exhaustion. Overall, SERINC2 remodels cancer development and serine metabolism in the tumor immune microenvironment (TIME), establishing an immunosuppressive and pro-tumoral milieu.

Serinc2 Drives the Progression of Cervical Cancer Through Regulating Myc Pathway

BACKGROUND

As one of the most common malignancies, cervical cancer (CC) seriously affects women's health. This study aimed to investigate the biological function of Serinc2 in CC.

METHODS

Serinc2 expression was surveyed utilizing immunohistochemistry, western blot, and qRT-PCR. CC cell viability, invasion, proliferation, migration, and apoptosis, were detected via CCK-8, Transwell assay, colony formation, wound healing assay, and flow cytometry. Glucose consumption, lactate production, and ATP levels were determined by the corresponding kit. The protein expression of c-Myc, PDK1, HK2, PFKP, LDHA, Snail, Vimentin, N-cadherin, and E-cadherin was detected via western blot. The interaction between the promoter of PFKP and Myc was confirmed through luciferase reporter assay and Chip assay. In vivo, to evaluate the function of Serinc2 on tumor growth, a xenograft mouse model was used.

RESULTS

In CC tissues and cells, Serinc2 was upregulated. In CC cells, knockdown of Serinc2 suppressed cell invasion, proliferation, migration, decreased the expression of Snail, Vimentin, N-cadherin, HK2, PFKP, LDHA, and PDK1, increased E-cadherin expression, reduced glucose consumption and the production of lactate and ATP, and induced cell apoptosis; Serinc2 overexpression led to the opposite results. Mechanically, Serinc2 promoted Myc expression, and Myc induced PFKP expression. Furthermore, overexpressed Myc abolished the inhibitive influences of Serinc2 knockdown on the malignant behaviors of CC cells. Additionally, knockdown of Serinc2 inhibited tumor growth and reduced the protein expression of c-Myc, PFKP, LDHA, and PDK1 in vivo.

CONCLUSIONS

Knockdown of Serinc2 inhibited the malignant progression of CC, which was achieved via Myc pathway. Our study provides novel insight into CC pathogenesis.

Serinc2 deficiency exacerbates sepsis-induced cardiomyopathy by enhancing necroptosis and apoptosis

In critical care medicine, sepsis is a potentially fatal syndrome characterized by multi-organ dysfunction and eventual failure. Sepsis-induced cardiomyopathy (SIC) is characterized by decreased venstricular contractility. Serine incorporator 2 (Serinc2) is a protein involved in phosphatidylserine biosynthesis and membrane incorporation. It may also be a protective factor in septic lung injury. However, it is unknown whether Serinc2 influences SIC onset or progression. In the present study, we found that Serinc2 was downregulated in the cardiomyocytes of cecal ligation and puncture (CLP)-induced SIC and in neonatal rat cardiomyocytes (NRCMs) exposed to lipopolysaccharides (LPS). Serinc2 knockout (KO) exacerbated sepsis-induced myocardial inflammation, necroptosis, apoptosis, myocardial damage, and contractility impairment. Furthermore, the lack of Serinc2 in cardiomyocytes aggravated LPS-induced cardiomyopathic inflammation, necroptosis, and apoptosis. An adenovirus overexpressing Serinc2 inhibited the inflammatory response and favored cardiomyocyte survival. A mechanistic analysis revealed that Serinc2 deficiency exacerbated LPS-induced cardiac dysfunction by inhibiting the protein kinase B (Akt)/glycogen synthase kinase 3 beta (GSK-3β) signaling pathway that regulates necrotic complex formation and apoptotic pathways in cardiomyopathy. The findings of the present work demonstrated that Serinc2 plays an essential role in SIC and is, therefore, promising as a prophylactic and therapeutic target for this condition.

RUNX1 methylation as a cancer biomarker in differentiating papillary thyroid cancer from benign thyroid nodules

Aim: It remains a challenge to accurately identify malignancy of thyroid nodules when biopsy is indeterminate. The authors aimed to investigate the abnormal DNA methylation signatures in papillary thyroid cancer (PTC) compared with benign thyroid nodules (BTNs). Methods: The authors performed genome profiling by 850K array and RNA sequencing in early-stage PTC and BTN tissue samples. The identified gene was validated in two independent case-control studies using mass spectrometry. Results: Hypomethylation of RUNX1 in PTC was identified and verified (all odds ratios: ≥1.50). RUNX1 methylation achieved good accuracy in differentiating early-stage PTC from BTNs, especially for younger women. Conclusion: The authors disclosed a significant association between RUNX1 hypomethylation and PTC, suggesting RUNX1 methylation as a potential biomarker for companion diagnosis of malignant thyroid nodules.

Methylome and transcriptome data integration reveals aberrantly regulated genes in equine sarcoids

DNA methylation is a key mechanism in transcription regulation, and aberrant methylation is a common and important mechanism in tumor initiation, maintenance, and progression. To find genes that are aberrantly regulated by altered methylation in horse sarcoids, we used reduced representation bisulfite sequencing (RRBS) accompanied by RNA sequencing (RNA-Seq) for methylome (whole genome DNA methylation sequencing) and transcriptome profiling, respectively. We found that the DNA methylation level was generally lower in lesion samples than in controls. In the analyzed samples, a total of 14,692 differentially methylated sites (DMSs) in the context of CpG (where cytosine and guanine are separated by a phosphate), and 11,712 differentially expressed genes (DEGs) were identified. The integration of the methylome and transcriptome data suggests that aberrant DNA methylation may be involved in the deregulation of expression of the 493 genes in equine sarcoid. Furthermore, enrichment analysis of the genes demonstrated the activation of multiple molecular pathways related to extracellular matrix (ECM), oxidative phosphorylation (OXPHOS), immune response, and disease processes that can be related to tumor progression. The results provide further insight into the epigenetic alterations in equine sarcoids and provide a valuable resource for follow-up studies to identify biomarkers for predicting susceptibility to this common condition in horses.

Association of DNA Promoter Methylation and BRAF Mutation in Thyroid Cancer

The BRAF V600E mutation and DNA promoter methylation play important roles in the pathogenesis of thyroid cancer (TC). However, the association of these genetic and epigenetic alterations is not clear. In this study, using paired tumor and surrounding normal tissue from the same patients, on a genome-wide scale we tried to identify (a) any association between BRAF mutation and DNA promoter methylation, and (b) if the molecular findings may provide a basis for therapeutic intervention. We included 40 patients with TC (female = 28, male = 12) without distant metastasis. BRAF mutation was present in 18 cases. We identified groups of differentially methylated loci (DML) that are found in (a) both BRAF mutant and wild type, (b) only in BRAF mutant tumors, and (c) only in BRAF wild type. BRAF mutation-specific promoter loci were more frequently hypomethylated, whereas BRAF wild-type-specific loci were more frequently hypermethylated. Common DML were enriched in cancer-related pathways, including the mismatch repair pathway and Wnt-signaling pathway. Wild-type-specific DML were enriched in RAS signaling. Methylation status of checkpoint signaling genes, as well as the T-cell inflamed genes, indicated an opportunity for the potential use of PDL1 inhibitors in BRAF mutant TC. Our study shows an association between BRAF mutation and methylation in TC that may have biological significance.