SHMT2 Overexpression Predicts Poor Prognosis in Intrahepatic Cholangiocarcinoma

Integrative Multi-omics Analysis Reveals Different Metabolic Phenotypes Based on Molecular Characteristics in Thyroid Cancer

PURPOSE

Thyroid cancer metabolic characteristics vary depending on the molecular subtype determined by mutational status. We aimed to investigate the molecular subtype-specific metabolic characteristics of thyroid cancers.

EXPERIMENTAL DESIGN

An integrative multi-omics analysis was conducted, incorporating transcriptomics, metabolomics, and proteomics data obtained from human tissues representing distinct molecular characteristics of thyroid cancers: BRAF-like (papillary thyroid cancer with BRAFV600E mutation; PTC-B), RAS-like (follicular thyroid cancer with RAS mutation; FTC-R), and ATC-like (anaplastic thyroid cancer with BRAFV600E or RAS mutation; ATC-B or ATC-R). To validate our findings, we employed tissue microarray of human thyroid cancer tissues and performed in vitro analyses of cancer cell phenotypes and metabolomic assays after inducing genetic knockdown.

RESULTS

Metabolic properties differed between differentiated thyroid cancers of PTC-B and FTC-R, but were similar in dedifferentiated thyroid cancers of ATC-B/R, regardless of their mutational status. Tricarboxylic acid (TCA) intermediates and branched-chain amino acids (BCAA) were enriched with the activation of TCA cycle only in FTC-R, whereas one-carbon metabolism and pyrimidine metabolism increased in both PTC-B and FTC-R and to a great extent in ATC-B/R. However, the protein expression levels of the BCAA transporter (SLC7A5) and a key enzyme in one-carbon metabolism (SHMT2) increased in all thyroid cancers and were particularly high in ATC-B/R. Knockdown of SLC7A5 or SHMT2 inhibited the migration and proliferation of thyroid cancer cell lines differently, depending on the mutational status.

CONCLUSIONS

These findings define the metabolic properties of each molecular subtype of thyroid cancers and identify metabolic vulnerabilities, providing a rationale for therapies targeting its altered metabolic pathways in advanced thyroid cancer.

The expression and clinical significance of serine hydroxymethyltransferase2 in gastric cancer

Background

Gastric cancer (GC) is one of the most common malignant tumours in the digestive system. Serine hydroxymethyltransferase 2 (SHMT2) is one of the key enzymes associated with serine metabolism. However, the prognostic role of SHMT2 in GC carcinogenesis has yet to be studied.

Methods

The expression of SHMT2 in human tumors and normal tissues was detected by the Assistant for Clinical Bioinformatics and Immunohistochemistry (IHC). The relationship of the expression of SHMT2 with clinical characteristics and survival data was analysed by the chi-square test, survival analysis and online databases. Finally, the correlation between SHMT2 expression and associated signalling channels, and molecules was analysed by online databases.

Results

SHMT2 was strongly expressed in numerous human cancers. The expression rate of SHMT2 was 56.44% in GC (P = 0.018). The survival analysis indicated that patients with high expression of SHMT2 had the worse overall survival (OS; log-rank P = 0.007). The expression of SHMT2 was correlated with tumour size (P = 0.034) and, TNM stage (P = 0.042). In particular, SHMT2, vessel invasion and M stage were independent factors for OS in GC (P = 0.044, P < 0.001, P < 0.001). The SHMT2 gene was substantially correlated with cell signalling pathways.

Conclusions

SHMT2 is highly expressed in GC and is associated with a poor prognosis. The exploration of its mechanism may be related to tumour proliferation, DNA repair and replication. SHMT2 is an independent prognostic risk factor and a potential biomarker for the diagnosis and treatment of GC.

Vital role of SHMT2 in diverse disease

One-carbon metabolism is essential for our human cells to carry out nucleotide synthesis, methylation, and reductive metabolism through one-carbon units, and these pathways ensure the high proliferation rate of cancer cells. Serine hydroxymethyltransferase 2 (SHMT2) is a key enzyme in one-carbon metabolism. This enzyme can convert serine into a one-carbon unit bound to tetrahydrofolate and glycine, ultimately supporting the synthesis of thymidine and purines and promoting the growth of cancer cells. Due to SHMT2's crucial role in the one-carbon cycle, it is ubiquitous in human cells and even in all organisms and highly conserved. Here, we summarize the impact of SHMT2 on the progression of various cancers to highlight its potential use in the development of cancer treatments.

The Influence of Mitochondrial Energy and 1C Metabolism on the Efficacy of Anticancer Drugs: Exploring Potential Mechanisms of Resistance

Mitochondria are the main energy factory in living cells. To rapidly proliferate and metastasize, neoplastic cells increase their energy requirements. Thus, mitochondria become one of the most important organelles for them. Indeed, much research shows the interplay between cancer chemoresistance and altered mitochondrial function. In this review, we focus on the differences in energy metabolism between cancer and normal cells to better understand their resistance and how to develop drugs targeting energy metabolism and nucleotide synthesis. One of the differences between cancer and normal cells is the higher nicotinamide adenine dinucleotide (NAD+) level, a cofactor for the tricarboxylic acid cycle (TCA), which enhances their proliferation and helps cancer cells survive under hypoxic conditions. An important change is a metabolic switch called the Warburg effect. This effect is based on the change of energy harvesting from oxygen-dependent transformation to oxidative phosphorylation (OXPHOS), adapting them to the tumor environment. Another mechanism is the high expression of one-carbon (1C) metabolism enzymes. Again, this allows cancer cells to increase proliferation by producing precursors for the synthesis of nucleotides and amino acids. We reviewed drugs in clinical practice and development targeting NAD+, OXPHOS, and 1C metabolism. Combining novel drugs with conventional antineoplastic agents may prove to be a promising new way of anticancer treatment.

SHMT2 is Associated with Tumor Purity, CD8+ T Immune Cells Infiltration, and a Novel Therapeutic Target in Four Different Human Cancers

AIMS

This study was launched to identify the SHMT2 associated Human Cancer subtypes.

BACKGROUND

Cancer is the 2nd leading cause of death worldwide. Previous reports revealed the limited involvement of SHMT2 in human cancer. In the current study, we comprehensively analyzed the role of SHMT2 in 24 major subtypes of human cancers using in silico approach and identified a few subtypes that are mainly associated with SHMT2.

OBJECTIVE

We aim to comprehensively analyze the role of SHMT2 in 24 major subtypes of human cancers using in silico approach and identified a few subtypes that are mainly associated with SHMT2. Earlier, limited knowledge exists in the medical literature regarding the involvement of Serine Hydroxymethyltransferase 2 (SHMT2) in human cancer.

METHODS

In the current study, we comprehensively analyzed the role of SHMT2 in 24 major subtypes of human cancers using in silico approach and identified a few subtypes that are mainly associated with SHMT2. Pan-cancer transcriptional expression profiling of SHMT2 was done using UALCAN while further validation was performed using GENT2. For translational profiling of SHMT2, we utilized Human Protein Atlas (HPA) platform. Promoter methylation, genetic alteration, and copy number variations (CNVs) profiles were analyzed through MEXPRESS and cBioPortal. Survival analysis was carried out through Kaplan-Meier (KM) plotter platform. Pathway enrichment analysis of SHMT2 was performed using DAVID, while the gene-drug network was drawn through CTD and Cytoscape. Furthermore, in the tumor microenvironment, a correlation between tumor purity, CD8+ T immune cells infiltration, and SHMT2 expression was accessed using TIMER.

RESULTS

SHMT2 was found overexpressed in 24 different subtypes of human cancers and its overexpression was significantly associated with the reduced Overall survival (OS) and Relapse-free survival durations of Breast cancer (BRCA), Kidney renal papillary cell carcinoma (KIRP), Liver hepatocellular carcinoma (LIHC), and Lung adenocarcinoma (LUAD) patients. This implies that SHMT2 plays a significant role in the development and progression of these cancers. We further noticed that SHMT2 was also up-regulated in BRCA, KIRP, LIHC, and LUAD patients of different clinicopathological features. Pathways enrichment analysis revealed the involvement of SHMT2 enriched genes in five diverse pathways. Furthermore, we also explored some interesting correlations between SHMT2 expression and promoter methylation, genetic alterations, CNVs, tumor purity, and CD8+ T immune cell infiltrates.

CONCLUSION

Our results suggested that overexpressed SHMT2 is correlated with the reduced OS and RFS of the BRCA, KIRP, LIHC, and LUAD patients and can be a potential diagnostic and prognostic biomarker for these cancers.

New molecular mechanisms in cholangiocarcinoma: signals triggering interleukin-6 production in tumor cells and KRAS co-opted epigenetic mediators driving metabolic reprogramming

Background

Cholangiocarcinoma (CCA) is still a deadly tumour. Histological and molecular aspects of thioacetamide (TAA)-induced intrahepatic CCA (iCCA) in rats mimic those of human iCCA. Carcinogenic changes and therapeutic vulnerabilities in CCA may be captured by molecular investigations in bile, where we performed bile proteomic and metabolomic analyses that help discovery yet unknown pathways relevant to human iCCA.

Methods

Cholangiocarcinogenesis was induced in rats (TAA) and mice (Jnk^Δhepa + CCl₄ + DEN model). We performed proteomic and metabolomic analyses in bile from control and CCA-bearing rats. Differential expression was validated in rat and human CCAs. Mechanisms were addressed in human CCA cells, including Huh28-KRAS^G12D cells. Cell signaling, growth, gene regulation and [U-¹³C]-D-glucose-serine fluxomics analyses were performed. In vivo studies were performed in the clinically-relevant iCCA mouse model.

Results

Pathways related to inflammation, oxidative stress and glucose metabolism were identified by proteomic analysis. Oxidative stress and high amounts of the oncogenesis-supporting amino acids serine and glycine were discovered by metabolomic studies. Most relevant hits were confirmed in rat and human CCAs (TCGA). Activation of interleukin-6 (IL6) and epidermal growth factor receptor (EGFR) pathways, and key genes in cancer-related glucose metabolic reprogramming, were validated in TAA-CCAs. In TAA-CCAs, G9a, an epigenetic pro-tumorigenic writer, was also increased. We show that EGFR signaling and mutant KRAS^G12D can both activate IL6 production in CCA cells. Furthermore, phosphoglycerate dehydrogenase (PHGDH), the rate-limiting enzyme in serine-glycine pathway, was upregulated in human iCCA correlating with G9a expression. In a G9a activity-dependent manner, KRAS^G12D promoted PHGDH expression, glucose flow towards serine synthesis, and increased CCA cell viability. KRAS^G12D CAA cells were more sensitive to PHGDH and G9a inhibition than controls. In mouse iCCA, G9a pharmacological targeting reduced PHGDH expression.

Conclusions

In CCA, we identified new pro-tumorigenic mechanisms: Activation of EGFR signaling or KRAS mutation drives IL6 expression in tumour cells; Glucose metabolism reprogramming in iCCA includes activation of the serine-glycine pathway; Mutant KRAS drives PHGDH expression in a G9a-dependent manner; PHGDH and G9a emerge as therapeutic targets in iCCA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02386-2.

Serine hydroxymethyltransferase 2 (SHMT2) potentiates the aggressive process of oral squamous cell carcinoma by binding to interleukin enhancer-binding factor 2 (ILF2)

Oral squamous cell carcinoma (OSCC) is a frequent threatening head and neck malignancy. Serine hydroxymethyltransferase 2 (SHMT2) was identified to be upregulated in OSCC and its high expression was associated with poor patient prognosis. This paper set out to assess the influence of SHMT2 on OSCC progression and the potential mechanisms related to interleukin enhancer-binding factor 2 (ILF2). First of all, reverse transcription-quantitative PCR (RT-qPCR) and western blot examined the expression of SHMT2 and ILF2 in OSCC cells. Cell Counting Kit-8 (CCK-8) and colony formation assays appraised cell proliferation. Terminal-deoxynucleotidyl Transferase Mediated Nick End Labeling (TUNEL) staining was to estimate the apoptotic rate of cells. Further, wound healing and transwell assays verified the migration and invasion of cells. Western blot was adopted to detect the expression of factors related to apoptosis, migration, and epithelial–mesenchymal transition (EMT). The possible interaction of SHMT2 and ILF2 was predicted by a Molecular INTeraction (MINT) and BioGRID databases and determined using co-immunoprecipitation (IP) assay. Subsequently, ILF2 was overexpressed to investigate whether SHMT2 regulated OSCC progression by binding to ILF2. Results implied that SHMT2 possessed increased expression in OSCC cells, and OSCC cell viability, migration, invasion, EMT were inhibited and apoptosis was potentiated after its silencing. ILF2 bound to SHMT2 and ILF2 expression was downregulated after SHMT2 silencing in OSCC cells. Importantly, ILF2 overexpression abolished the suppressive role of SHMT2 interference in the progression of OSCC. Collectively, SHMT2 could promote the progression of OSCC by binding to ILF2.

Exploration of the Effect on Genome-Wide DNA Methylation by miR-143 Knock-Out in Mice Liver

MiR-143 play an important role in hepatocellular carcinoma and liver fibrosis via inhibiting hepatoma cell proliferation. DNA methyltransferase 3 alpha (DNMT3a), as a target of miR-143, regulates the development of primary organic solid tumors through DNA methylation mechanisms. However, the effect of miR-143 on DNA methylation profiles in liver is unclear. In this study, we used Whole-Genome Bisulfite Sequencing (WGBS) to detect the differentially methylated regions (DMRs), and investigated DMR-related genes and their enriched pathways by miR-143. We found that methylated cytosines increased 0.19% in the miR-143 knock-out (KO) liver fed with high-fat diet (HFD), compared with the wild type (WT). Furthermore, compared with the WT group, the CG methylation patterns of the KO group showed lower CG methylation levels in CG islands (CGIs), promoters and hypermethylation in CGI shores, 5'UTRs, exons, introns, 3'UTRs, and repeat regions. A total of 984 DMRs were identified between the WT and KO groups consisting of 559 hypermethylation and 425 hypomethylation DMRs. Furthermore, DMR-related genes were enriched in metabolism pathways such as carbon metabolism (serine hydroxymethyltransferase 2 (Shmt2), acyl-Coenzyme A dehydrogenase medium chain (Acadm)), arginine and proline metabolism (spermine synthase (Sms), proline dehydrogenase (Prodh2)) and purine metabolism (phosphoribosyl pyrophosphate synthetase 2 (Prps2)). In summary, we are the first to report the change in whole-genome methylation levels by miR-143-null through WGBS in mice liver, and provide an experimental basis for clinical diagnosis and treatment in liver diseases, indicating that miR-143 may be a potential therapeutic target and biomarker for liver damage-associated diseases and hepatocellular carcinoma.

Metabolism-Associated Epigenetic and Immunoepigenetic Reprogramming in Liver Cancer

Metabolic reprogramming and epigenetic changes have been characterized as hallmarks of liver cancer. Independently of etiology, oncogenic pathways as well as the availability of different energetic substrates critically influence cellular metabolism, and the resulting perturbations often cause aberrant epigenetic alterations, not only in cancer cells but also in the hepatic tumor microenvironment. Metabolic intermediates serve as crucial substrates for various epigenetic modulations, from post-translational modification of histones to DNA methylation. In turn, epigenetic changes can alter the expression of metabolic genes supporting on the one hand, the increased energetic demand of cancer cells and, on the other hand, influence the activity of tumor-associated immune cell populations. In this review, we will illustrate the most recent findings about metabolic reprogramming in liver cancer. We will focus on the metabolic changes characterizing the tumor microenvironment and on how these alterations impact on epigenetic mechanisms involved in the malignant progression. Furthermore, we will report our current knowledge about the influence of cancer-specific metabolites on epigenetic reprogramming of immune cells and we will highlight how this favors a tumor-permissive immune environment. Finally, we will review the current strategies to target metabolic and epigenetic pathways and their therapeutic potential in liver cancer, alone or in combinatorial approaches.

Roles of Mitochondrial Serine Hydroxymethyltransferase 2 (SHMT2) in Human Carcinogenesis

In the last few years, cellular metabolic reprogramming has been acknowledged as a hallmark of human cancer and evaluated for its crucial role in supporting the proliferation and survival of human cancer cells. In a variety of human tumours, including hepatocellular carcinoma (HCC), breast cancer and non-small-cell lung cancer (NSCLC), a large amount of carbon is reused in serine/glycine biosynthesis, accompanied by higher expression of the key glycine synthetic enzyme mitochondrial serine hydroxymethyltransferase 2 (SHMT2). This enzyme can convert serine into glycine and a tetrahydrofolate-bound one-carbon unit, ultimately supporting thymidine synthesis and purine synthesis and promoting tumour growth. In tumour samples, elevated expression of SHMT2 was found to be associated with poor prognosis. In this review, the pivotal roles of SHMT2 in human carcinogenesis are described, highlighting the underlying regulatory mechanisms through promotion of tumour progression. In conclusion, SHMT2 may serve as a prognostic marker and a target for anticancer therapies.

Regulation of the HTRA2 Protease Activity by an Inhibitory Antibody-Derived Peptide Ligand and the Influence on HTRA2-Specific Protein Interaction Networks in Retinal Tissues

The mitochondrial serine protease HTRA2 has many versatile biological functions ranging from being an important regulator of apoptosis to being an essential component for neuronal cell survival and mitochondrial homeostasis. Loss of HTRA2 protease function is known to cause neurodegeneration, whereas overactivation of its proteolytic function is associated with cell death and inflammation. In accordance with this, our group verified in a recent study that the synthetic peptide ASGYTFTNYGLSWVR, encoding the hypervariable sequence part of an antibody, showed a high affinity for the target protein HTRA2 and triggered neuroprotection in an in vitro organ culture model for glaucoma. To unravel this neuroprotective mechanism, the present study showed for the first time that the synthetic CDR1 peptide significantly (p < 0.01) inhibited the proteolytic activity of HTRA2 up to 50% using a specific protease function assay. Furthermore, using state-of-the-art co-immunoprecipitation technologies in combination with high-resolution MS, we identified 50 significant protein interaction partners of HTRA2 in the retina of house swine (p < 0.01; log₂ fold change > 1.5). Interestingly, 72% of the HTRA2-specific interactions (23 of 31 binders) were inhibited by additional treatment with UCF-101 (HTRA2 protease inhibitor) or the synthetic CDR peptide. On the other hand, the remaining 19 binders of HTRA2 were exclusively identified in the UCF101 and/or CDR group. However, many of the interactors were involved in the ER to Golgi anterograde transport (e.g., AP3D1), aggrephagy (e.g., PSMC1), and the pyruvate metabolism/citric acid cycle (e.g., SHMT2), and illustrated the complex protein interaction networks of HTRA2 in neurological tissues. In conclusion, the present study provides, for the first time, a comprehensive protein catalogue of HTRA2-specific interaction partners in the retina, and will serve as reference map in the future for studies focusing on HTRA2-mediated neurodegeneration.

SHMT2 expression as a diagnostic and prognostic marker for thyroid cancer

BACKGROUND

Catabolism of serine via serine hydroxymethyltransferase2 (SHMT2) through the mitochondrial one-carbon unit pathway is important in tumorigenesis. Therefore, SHMT2 may play a role in thyroid cancer.

METHODS

Thyroid tissue samples and The Cancer Genome Atlas (TCGA) database were used to evaluate SHMT2 expression in thyroid tissues and the association with clinical outcomes.

RESULTS

SHMT2 protein expression was evaluated in thyroid tissues consisting of 52 benign nodules, 129 papillary thyroid carcinomas (PTC) and matched normal samples, and 20 anaplastic thyroid carcinomas (ATC). ATCs presented the highest (95.0%) positivity of SMHT2 protein expression. PTCs showed the second highest (73.6%) positivity of SHMT2 expression, which was significantly higher than that of benign nodules (19.2%, P = 0.016) and normal thyroid tissues (0%, P < 0.001). Analysis of TCGA data showed that SHMT2 messenger RNA (mRNA) expression was significantly higher in tumors than in normal tissues (P < 0.001). When we classified thyroid cancer into high and low groups according to SHMT2 mRNA expression levels, the thyroid differentiation score for the high SHMT2 group was significantly lower than that of the low SHMT2 group (P < 0.001). There was also a significant correlation between SHMT2 mRNA expression and the stemness index (r = 0.41, P < 0.001). The high SHMT2 group had more advanced TNM stages and shorter progression-free survival rates than the low SHMT2 group (P < 0.01 and P = 0.007, respectively).

CONCLUSION

SHMT2 expression is higher in thyroid cancers than normal or benign tissues and is associated with de-differentiation and poor clinical outcomes. Thus, SHMT2 might be useful as a diagnostic and prognostic marker for thyroid cancer.

Overexpression of SHMT2 Predicts a Poor Prognosis and Promotes Tumor Cell Growth in Bladder Cancer

SHMT2 was overexpressed in many tumors, however, the role of SHMT2 in bladder cancer (BLCA) remains unclear. We first analyzed the expression pattern of SHMT2 in BLCA using the TNMplot, Oncomine, the Cancer Genome Atlas (TCGA), and the Gene Expression Omnibus (GEO) databases. Next, the association between SHMT2 expression and overall survival (OS)/disease-free survival (DFS) in BLCA patients were analyzed using TCGA and PrognoScan database. The correlation between SHMT2 expression and clinicopathology was determined using TCGA database. Furthermore, the genes co-expressed with SHMT2 and their underlying molecular function in BLCA were explored based on the Oncomine database, Metascape and gene set enrichment analysis (GSEA). Finally, the effects of SHMT2 on cell proliferation, cell cycle, and apoptosis were assessed using in vitro experiments. As a results, SHMT2 was significantly overexpressed in BLCA tissues and cells compared to normal bladder tissues and cells. A high SHMT2 expression predicts a poor OS of BLCA patients. In addition, SHMT2 expression was higher in patients with a high tumor grade and in those who were older than 60 years. However, the expression of SHMT2 was not correlated with gender, tumor stage, lymph node stage, and distant metastasis stage. Finally, overexpression of SHMT2 promoted BLCA cell proliferation and suppressed apoptosis, the silencing of SHMT2 significantly inhibited BLCA cell proliferation by impairing the cell cycle, and promoting apoptosis. SHMT2 mediates BLCA cells growth by regulating STAT3 signaling. In summary, SHMT2 regulates the proliferation, cell cycle and apoptosis of BLCA cells, and may act as a candidate therapeutic target for BLCA.

The loss of SHMT2 mediates 5-fluorouracil chemoresistance in colorectal cancer by upregulating autophagy

5-Fluorouracil (5-FU)-based chemotherapy is the first-line treatment for colorectal cancer (CRC) but is hampered by chemoresistance. Despite its impact on patient survival, the mechanism underlying chemoresistance against 5-FU remains poorly understood. Here, we identified serine hydroxymethyltransferase-2 (SHMT2) as a critical regulator of 5-FU chemoresistance in CRC. SHMT2 inhibits autophagy by binding cytosolic p53 instead of metabolism. SHMT2 prevents cytosolic p53 degradation by inhibiting the binding of p53 and HDM2. Under 5-FU treatment, SHMT2 depletion promotes autophagy and inhibits apoptosis. Autophagy inhibitors decrease low SHMT2-induced 5-FU resistance in vitro and in vivo. Finally, the lethality of 5-FU treatment to CRC cells was enhanced by treatment with the autophagy inhibitor chloroquine in patient-derived and CRC cell xenograft models. Taken together, our findings indicate that autophagy induced by low SHMT2 levels mediates 5-FU resistance in CRC. These results reveal the SHMT2-p53 interaction as a novel therapeutic target and provide a potential opportunity to reduce chemoresistance.

Silencing SHMT2 inhibits the progression of tongue squamous cell carcinoma through cell cycle regulation

Background

Serine hydroxymethyltransferase 2 (SHMT2) is a vital metabolic enzyme in one carbon metabolism catalyzing the conversion of serine to glycine, which has been reported to play a crucial role in the progression of tumors. However, its function in tongue squamous cell carcinoma (TSCC) remains unclear.

Methods

SHMT2 expression was analyzed using samples in online databases, and was assessed through immunohistochemistry staining of collected clinical specimens. The correlation between SHMT2 expression and the cell cycle was predicted through bioinformatic analysis, including weighted gene co-expression network analysis (WGCNA) and gene set enrichment analysis (GSEA). After transfection with siRNA, CCK8 assay, Edu staining, flow cytometry, trans-well assay, and wound healing experiments were performed to verify the functional role of SHMT2 in vitro. A stable cell line with SHMT2 silencing was established to detect the oncogenic function of SHMT2 in vivo.

Results

The expression of SHMT2 was up-regulated in TSCC tissues and cell lines compared with normal groups, and highly expressed SHMT2 significantly indicated a poorer clinical outcome for TSCC patients. Bioinformatic analysis found that high expression of SHMT2 was closely related with biologic process including cell cycle and cell cycle G1/S transition. Down regulating of SHMT2 significantly suppressed the proliferation, invasive and migrative ability of TSCC cells, and induced the prolongation of the G1 phase of the cell cycle in vitro. Furthermore, western blot showed that cell cycle-related regulators such as cyclin-dependent kinase 4 (CDK4) and cyclinD1 expression levels were decreased, while the expression levels of the cyclin-dependent kinase inhibitors p21^Cip1 and p27^Kip1 were increased after SHMT2 knockdown. Silencing SHMT2 in the HN6 cell line using short hairpin RNA also impeded tumor growth in vivo.

Conclusions

Overexpression of SHMT2 in TSCC indicated low survival rates, and was associated with aggressive behaviors of TSCC. It was also found to be involved in cell cycle regulation of TSCC cells. SHMT2 may serve as a novel prognostic indicator of TSCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-01880-5.

Identification of SHMT2 as a Potential Prognostic Biomarker and Correlating with Immune Infiltrates in Lung Adenocarcinoma

It has attracted growing attention that the role of serine hydroxy methyl transferase 2 (SHMT2) in various types of cancers. However, the prognostic role of SHMT2 in lung adenocarcinoma (LUAD) and its relationship with immune cell infiltration is not clear. In this study, the information of mRNA expression and clinic data in LUAD were, respectively, downloaded from the GEO and TCGA database. We conducted a biological analysis to select the signature gene SHMT2. Online databases including Oncomine, GEPIA, TISIDB, TIMER, and HPA were applied to analyze the characterization of SHMT2 expression, prognosis, and the correlation with immune infiltration in LUAD. The mRNA expression and protein expression of SHMT2 in LUAD tissues were higher than in normal tissue. A Kaplan-Meier analysis showed that patients with lower expression level of SHMT2 had a better overall survival rate. Multivariate analysis and the Cox proportional hazard regression model revealed that SHMT2 expression was an independent prognostic factor in patients with LUAD. Meanwhile, the gene SHMT2 was highly associated with tumor-infiltrating lymphocytes in LUAD. These results suggest that the SHMT2 gene is a promising candidate as a potential prognostic biomarker and highly associated with different types of immune cell infiltration in LUAD.

Therapeutic targeting of the mitochondrial one-carbon pathway: perspectives, pitfalls, and potential

Most of the drugs currently prescribed for cancer treatment are riddled with substantial side effects. In order to develop more effective and specific strategies to treat cancer, it is of importance to understand the biology of drug targets, particularly the newly emerging ones. A comprehensive evaluation of these targets will benefit drug development with increased likelihood for success in clinical trials. The folate-mediated one-carbon (1C) metabolism pathway has drawn renewed attention as it is often hyperactivated in cancer and inhibition of this pathway displays promise in developing anticancer treatment with fewer side effects. Here, we systematically review individual enzymes in the 1C pathway and their compartmentalization to mitochondria and cytosol. Based on these insight, we conclude that (1) except the known 1C targets (DHFR, GART, and TYMS), MTHFD2 emerges as good drug target, especially for treating hematopoietic cancers such as CLL, AML, and T-cell lymphoma; (2) SHMT2 and MTHFD1L are potential drug targets; and (3) MTHFD2L and ALDH1L2 should not be considered as drug targets. We highlight MTHFD2 as an excellent therapeutic target and SHMT2 as a complementary target based on structural/biochemical considerations and up-to-date inhibitor development, which underscores the perspectives of their therapeutic potential.

A Review of Small-Molecule Inhibitors of One-Carbon Enzymes: SHMT2 and MTHFD2 in the Spotlight

Metabolic reprogramming is a key hallmark of cancer and shifts cellular metabolism to meet the demands of biomass production necessary for abnormal cell reproduction. One-carbon metabolism (1CM) contributes to many biosynthetic pathways that fuel growth and is comprised of a complex network of enzymes. Methotrexate and 5-fluorouracil were pioneering drugs in this field and are still widely used today as anticancer agents as well as for other diseases such as arthritis. Besides dihydrofolate reductase and thymidylate synthase, two other enzymes of the folate cycle arm of 1CM have not been targeted clinically: serine hydroxymethyltransferase (SHMT) and methylenetetrahydrofolate dehydrogenase (MTHFD). An increasing body of literature suggests that the mitochondrial isoforms of these enzymes (SHMT2 and MTHFD2) are clinically relevant in the context of cancer. In this review, we focused on the 1CM pathway as a target for cancer therapy and, in particular, SHMT2 and MTHFD2. The function, regulation, and clinical relevance of SHMT2 and MTHFD2 are all discussed. We expand on previous clinical studies and evaluate the prognostic significance of these critical enzymes by performing a pan-cancer analysis of patient data from the The Cancer Genome Atlas and a transcriptional coexpression network enrichment analysis. We also provide an overview of preclinical and clinical inhibitors targeting the folate pathway, the methionine cycle, and folate-dependent purine biosynthesis enzymes.

Resveratrol's Anti-Cancer Effects through the Modulation of Tumor Glucose Metabolism

Simple Summary

The prevention and treatment of cancer is an ongoing medical challenge. In the context of personalized medicine, the well-studied polyphenol resveratrol could complement classical tumor therapy. It may affect key processes such as inflammation, angiogenesis, proliferation, metastasis, glucose metabolism, and apoptosis in various cancers because resveratrol acts as a multi-targeting agent by modulating multiple signal transduction pathways. This review article focuses on resveratrol’s ability to modify tumor glucose metabolism and its associated therapeutic capacity. Resveratrol reduces glucose uptake and glycolysis by affecting Glut1, PFK1, HIF-1α, ROS, PDH, and the CamKKB/AMPK pathway. It also inhibits cell growth, invasion, and proliferation by targeting NF-kB, Sirt1, Sirt3, LDH, PI-3K, mTOR, PKM2, R5P, G6PD, TKT, talin, and PGAM. In addition, resveratrol induces apoptosis by targeting integrin, p53, LDH, and FAK. In conclusion, resveratrol has many potentials to intervene in tumor processes if bioavailability can be increased and this natural compound can be used selectively.

Abstract

Tumor cells develop several metabolic reprogramming strategies, such as increased glucose uptake and utilization via aerobic glycolysis and fermentation of glucose to lactate; these lead to a low pH environment in which the cancer cells thrive and evade apoptosis. These characteristics of tumor cells are known as the Warburg effect. Adaptive metabolic alterations in cancer cells can be attributed to mutations in key metabolic enzymes and transcription factors. The features of the Warburg phenotype may serve as promising markers for the early detection and treatment of tumors. Besides, the glycolytic process of tumors is reversible and could represent a therapeutic target. So-called mono-target therapies are often unsafe and ineffective, and have a high prevalence of recurrence. Their success is hindered by the ability of tumor cells to simultaneously develop multiple chemoresistance pathways. Therefore, agents that modify several cellular targets, such as energy restriction to target tumor cells specifically, have therapeutic potential. Resveratrol, a natural active polyphenol found in grapes and red wine and used in many traditional medicines, is known for its ability to target multiple components of signaling pathways in tumors, leading to the suppression of cell proliferation, activation of apoptosis, and regression in tumor growth. Here, we describe current knowledge on the various mechanisms by which resveratrol modulates glucose metabolism, its potential as an imitator of caloric restriction, and its therapeutic capacity in tumors.

Mitocans Revisited: Mitochondrial Targeting as Efficient Anti-Cancer Therapy

Mitochondria are essential cellular organelles, controlling multiple signalling pathways critical for cell survival and cell death. Increasing evidence suggests that mitochondrial metabolism and functions are indispensable in tumorigenesis and cancer progression, rendering mitochondria and mitochondrial functions as plausible targets for anti-cancer therapeutics. In this review, we summarised the major strategies of selective targeting of mitochondria and their functions to combat cancer, including targeting mitochondrial metabolism, the electron transport chain and tricarboxylic acid cycle, mitochondrial redox signalling pathways, and ROS homeostasis. We highlight that delivering anti-cancer drugs into mitochondria exhibits enormous potential for future cancer therapeutic strategies, with a great advantage of potentially overcoming drug resistance. Mitocans, exemplified by mitochondrially targeted vitamin E succinate and tamoxifen (MitoTam), selectively target cancer cell mitochondria and efficiently kill multiple types of cancer cells by disrupting mitochondrial function, with MitoTam currently undergoing a clinical trial.

Evaluating the clinical significance of SHMT2 and its co-expressed gene in human kidney cancer

Background

Kidney cancer is one of the most common cancers in the world. It is necessary to clarify its underlying mechanism and find its prognostic biomarkers. Current studies showed that SHMT2 may be participated in several kinds of cancer.

Methods

Our studies investigated the expression of SHMT2 in kidney cancer by Oncomine, Human Protein Atlas database and ULCAN database. Meanwhile, we found its co-expression gene by cBioPortal online tool and validated their relationship in A498 and ACHN cells by cell transfection, western blot and qRT-PCR. Besides these, we also explored their prognostic values via the Kaplan–Meier plotter database in different types of kidney cancer patients.

Results

SHMT2 was found to be increased in 7 kidney cancer datasets, compared to normal renal tissues. For the cancer stages, ages and races, there existed significant difference in the expression of SHMT2 among different groups by mining of the UALCAN database. High SHMT2 expression is associated with poor overall survival in patients with kidney cancer. Among all co-expressed genes, NDUFA4L2 and SHMT2 had a high co-expression efficient. SHMT2 overexpression led to the increased expression of NDUFA4L2 at both mRNA and protein levels. Like SHMT2, overexpressed NDUFA4L2 also was associated with worse overall survival in patients with kidney cancer.

Conclusion

Based on above results, overexpressed SHMT2 and its co-expressed gene NDUFA4L2 were all correlated with the prognosis in kidney cancer. The present study might be benefit for better understanding the clinical significance of SHMT2 and provided a potential therapeutic target for kidney cancer in future.

Increased Expression of SHMT2 Is Associated With Poor Prognosis and Advanced Pathological Grade in Oral Squamous Cell Carcinoma

This study focused on the expression of mitochondrial serine hydroxymethyltransferase (SHMT2) in oral squamous cell carcinoma (OSCC) and its correlation with clinical traits and the prognosis of OSCC patients. Immunochemical staining and Western blotting were used to quantify the expression of SHMT2 and related immune markers in OSCC. Using OSCC microarrays and The Cancer Genome Atlas (TCGA) database, we evaluated the association between SHMT2 and various clinical traits. We found that increased expression of SHMT2 was detected in OSCC and correlated with advanced pathological grade and recurrence of OSCC. By a multivariate Cox proportional hazard model, high expression of SHMT2 was shown to indicate a negative prognosis. In addition, in the OSCC microenvironment, increasing the expression of SHMT2 was associated with high expression levels of programmed cell death-ligand 1 (PD-L1), CKLF-like MARVEL transmembrane domain containing 6 (CMTM6), V-type immunoglobulin domain-containing suppressor (VISTA), B7-H4, Slug, and CD317. In the future, more effort will be required to investigate the role of SHMT2 in the OSCC microenvironment.

The Roles of Mitochondrial Folate Metabolism in Supporting Mitochondrial DNA Synthesis, Oxidative Phosphorylation, and Cellular Function

Folate-mediated one-carbon metabolism (FOCM) is compartmentalized within human cells to the cytosol, nucleus, and mitochondria. The recent identifications of mitochondria-specific, folate-dependent thymidylate [deoxythymidine monophosphate (dTMP)] synthesis together with discoveries indicating the critical role of mitochondrial FOCM in cancer progression have renewed interest in understanding this metabolic pathway. The goal of this narrative review is to summarize recent advances in the field of one-carbon metabolism, with an emphasis on the biological importance of mitochondrial FOCM in maintaining mitochondrial DNA integrity and mitochondrial function, as well as the reprogramming of mitochondrial FOCM in cancer. Elucidation of the roles and regulation of mitochondrial FOCM will contribute to a better understanding of the mechanisms underlying folate-associated pathologies.

Cancer proteome and metabolite changes linked to SHMT2

Serine hydroxymethyltransferase 2 (SHMT2) converts serine plus tetrahydrofolate (THF) into glycine plus methylene-THF and is upregulated at the protein level in lung and other cancers. In order to better understand the role of SHMT2 in cancer a model system of HeLa cells engineered for inducible over-expression or knock-down of SHMT2 was characterized for cell proliferation and changes in metabolites and proteome as a function of SHMT2. Ectopic over-expression of SHMT2 increased cell proliferation in vitro and tumor growth in vivo. Knockdown of SHMT2 expression in vitro caused a state of glycine auxotrophy and accumulation of phosphoribosylaminoimidazolecarboxamide (AICAR), an intermediate of folate/1-carbon-pathway-dependent de novo purine nucleotide synthesis. Decreased glycine in the HeLa cell-based xenograft tumors with knocked down SHMT2 was potentiated by administration of the anti-hyperglycinemia agent benzoate. However, tumor growth was not affected by SHMT2 knockdown with or without benzoate treatment. Benzoate inhibited cell proliferation in vitro, but this was independent of SHMT2 modulation. The abundance of proteins of mitochondrial respiration complexes 1 and 3 was inversely correlated with SHMT2 levels. Proximity biotinylation in vivo (BioID) identified 48 mostly mitochondrial proteins associated with SHMT2 including the mitochondrial enzymes Acyl-CoA thioesterase (ACOT2) and glutamate dehydrogenase (GLUD1) along with more than 20 proteins from mitochondrial respiration complexes 1 and 3. These data provide insights into possible mechanisms through which elevated SHMT2 in cancers may be linked to changes in metabolism and mitochondrial function.

[Protective effect of serine methyltransferase against hepatic ischemia-reperfusion injury in mice]

OBJECTIVE

To investigate the protective effect of serine hydroxymethyl transferase 2 (SHMT2) against hepatic ischemia-reperfusion injury in mice.

METHODS

Sixty C57BL/6 mice were divided equally into sham-operated group, saline adeno-associated virus group (AVV-GFP), and adeno-associated virus silencing group (AAV-SHMT2). The adeno-associated virus and normal saline were injected into the tail vein of the mice 2 weeks before establishment of a 70% ischemia-reperfusion model in the liver. qPCR, Western blotting, immunofluorescence and immunohistochemistry were used to detect the changes of AST/ALT concentration, SHMT2, JNK, NF-κB, caspase-3 and downstream inflammatory factors in the mice, and HE staining was used to observe the pathological damage of the liver tissue in each group; the cell apoptosis in the liver was detected using TUNEL assay.

RESULTS

The expression of SHMT2 increased with time after hepatic ischemia-reperfusion and reached the highest level at 24 h (the relative expression was 1.5, P &lt; 0.05). At 24 h after hepatic ischemia-reperfusion, the levels of AST/ALT in AAV-SHMT2 group (588/416 U/L) were significantly higher than those in the control group (416/345 U/L) and the empty vector group (387/321 U/L) (P &lt; 0.05). Compared with those in the control group and the empty vector group, the level of SHMT2 was significantly decreased in AAV-SHMT2 group (with a relative expression of 0.24, P &lt; 0.05), the levels of p-JNK and p-p65 were significantly increased (relative expression of 0.80 and 0.97, respectively, P &lt; 0.05), and the levels TNF-α and IL-1β were consistently elevated (relative expression levels of 1.6 and 1.2, respectively, P &lt; 0.05). No significant differences were found in these parameters between the empty vector group and the control group (P&gt;0.05).

CONCLUSIONS

SHMT2 may alleviate liver cell apoptosis in mice with hepatic ischemia-reperfusion injury by inhibiting the activation of JNK pathway and excessive activation of NF-κB pathway to reduce hepatic damage.

Therapeutic Targeting of Mitochondrial One-Carbon Metabolism in Cancer

One-carbon (1C) metabolism encompasses folate-mediated 1C transfer reactions and related processes, including nucleotide and amino acid biosynthesis, antioxidant regeneration, and epigenetic regulation. 1C pathways are compartmentalized in the cytosol, mitochondria, and nucleus. 1C metabolism in the cytosol has been an important therapeutic target for cancer since the inception of modern chemotherapy, and "antifolates" targeting cytosolic 1C pathways continue to be a mainstay of the chemotherapy armamentarium for cancer. Recent insights into the complexities of 1C metabolism in cancer cells, including the critical role of the mitochondrial 1C pathway as a source of 1C units, glycine, reducing equivalents, and ATP, have spurred the discovery of novel compounds that target these reactions, with particular focus on 5,10-methylene tetrahydrofolate dehydrogenase 2 and serine hydroxymethyltransferase 2. In this review, we discuss key aspects of 1C metabolism, with emphasis on the importance of mitochondrial 1C metabolism to metabolic homeostasis, its relationship with the oncogenic phenotype, and its therapeutic potential for cancer.

SHMT2 Promotes Liver Regeneration Through Glycine-activated Akt/mTOR Pathway

BACKGROUND

The development of liver transplantation (LT) is increasingly being limited by the unavailability of liver grafts. Unique regenerative capacity of liver in response to injuries makes living-donor liver transplantation (LDLT) a feasible strategy to meet clinical demands. Serine hydroxymethyl-transferase 2 (SHMT2) serves as the key enzyme in the biosynthesis of glycine. Glycine affects the activity of mammalian target of rapamycin (mTOR), which is important for cellular growth and proliferation. In this study, the effects of SHMT2 on mouse liver regeneration were investigated using a classical partial hepatectomy (PH) model.

METHODS

In vivo, PH was performed on mice with or without knockdown of SHMT2. In vitro, SHMT2 was overexpressed in primary hepatocytes, which were cultured in customized Dulbecco's modified eagle media and LY294002 (an Akt inhibitor). Relevant indexes of liver regeneration, cell proliferation, and Akt/mTOR signal pathways were analyzed.

RESULTS

After PH, the expression levels of SHMT2 fluctuated with time and knockdown of SHMT2 in vivo lowered the regenerative ability of liver, with reduced glycine levels compared to the scramble group. In addition, overexpression of SHMT2 in hepatocytes boosted glycine production while enhancing Akt/mTOR pathway activity. These results were validated by the application of LY294002 in vitro.

CONCLUSIONS

SHMT2 can contribute to liver regeneration after PH, and this is likely related to the activation of Akt/mTOR signaling pathway by its metabolic product, glycine, in hepatocytes. These results might have therapeutic implications for the prognosis of patients undergoing hepatic resection or transplantation.

High expression of folate cycle enzyme MTHFD1L correlates with poor prognosis and increased proliferation and migration in colorectal cancer

Aims: To investigate the expression and clinical significance of methylenetetrahydrofolate dehydrogenase 1-like (MTHFD1L) in colorectal cancer (CRC) and its effect on CRC cells proliferation and migration.

Methods: 59 fresh CRC tissue samples and matched normal tissues, 176 archive CRC tissue samples and 8 CRC cell lines were tested MTHFD1L by western blot and immunohistochemistry, respectively. The relationship between MTHFD1L expression, clinical significance and prognosis was analyzed by chi-square test and survival analysis. MTT assay, plate clonal formation assay and scratch assay were used to verify the effect of MTHFD1L on the proliferation and migration in CRC cell lines.

Results: The results showed that the protein level of MTHFD1L in CRC was significantly higher than that in adjacent normal tissues (p<0.01). The expression of MTHFD1L in CRC was positively correlated with the degree of tumor differentiation, TNM classification, tumor invasion, lymph node metastasis, and distant metastasis. Survival analysis showed that CRC patients with high MTHFD1L expression had a lower 5-year survival rate and the expression of MTHFD1L was an independent adverse factor for the CRC prognosis (p<0.05). Down-regulation of MTHFD1L inhibited the proliferation and migration of DLD-1 and HCT116 CRC cell lines.

Conclusion: These findings reveal that MTHFD1L is highly expressive in CRC and associated with poor prognosis, and MTHDF1L can increase colorectal cancer cell proliferation and migration. Therefore, MTHFD1L may serve as a predictor and a potential therapeutic target for CRC.

Downregulating Serine Hydroxymethyltransferase 2 Deteriorates Hepatic Ischemia-Reperfusion Injury through ROS/JNK/P53 Signaling in Mice

Background

Serine hydroxymethyltransferase 2 (SHMT2) activity ensures that cells have a survival advantage in ischemic conditions and regulates redox homeostasis. In this study, we aimed to investigate the role of SHMT2 after hepatic ischemia-reperfusion (IR), which involves hypoxia, ischemic conditions, and cell apoptosis.

Methods

A 70% IR model was established in C57BL/6J mice with or without SHMT2 knockdown. H&E staining, liver weight/body weight, serum alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels and cell apoptosis were tested to analyze liver damage and function. Then, the related cellular signals were probed.

Results

The level of SHMT2 protein was significantly increased at 24 h and 48 h after IR (p < 0.001). Mice in the shSHMT2 group showed more necrotic areas and histological damage at 24 h (p < 0.01) after IR and higher levels of serum ALT and AST (p < 0.05) compared with those of mice in the scramble group. After IR for 24 h, the expression of TUNEL in the shSHMT2 group was significantly higher than that in the scramble group, as shown by histological analysis (p < 0.01). Mechanistically, the JNK/P53 signaling pathway was activated by IR, and knockdown of SHMT2 exacerbated hepatocyte apoptosis.

Conclusions

Knockdown of SHMT2 worsens IR injury through the ROS/JNK/P53 signaling pathway. Our discovery expands the understanding of both molecular and metabolic mechanisms involved in IR. SHMT2 is a possible therapeutic target to improve the prognosis of liver transplantation (LT) and subtotal hepatectomy.

Shmt2: A Stat3 Signaling New Player in Prostate Cancer Energy Metabolism

Prostate cancer (PCa) is a multifactorial disease characterized by the aberrant activity of different regulatory pathways. STAT3 protein mediates some of these pathways and its activation is implicated in the modulation of several metabolic enzymes. A bioinformatic analysis indicated a STAT3 binding site in the upstream region of SHMT2 gene. We demonstrated that in LNCaP, PCa cells’ SHMT2 expression is upregulated by the JAK2/STAT3 canonical pathway upon IL-6 stimulation. Activation of SHTM2 leads to a decrease in serine levels, pushing PKM2 towards the nuclear compartment where it can activate STAT3 in a non-canonical fashion that in turn promotes a transient shift toward anaerobic metabolism. These results were also confirmed on FFPE prostate tissue sections at different Gleason scores. STAT3/SHMT2/PKM2 loop in LNCaP cells can modulate a metabolic shift in response to inflammation at early stages of cancer progression, whereas a non-canonical STAT3 activation involving the STAT3/HIF-1α/PKM2 loop is responsible for the maintenance of Warburg effect distinctive of more aggressive PCa cells. Chronic inflammation might thus prime the transition of PCa cells towards more advanced stages, and SHMT2 could represent a missing factor to further understand the molecular mechanisms responsible for the transition of prostate cancer towards a more aggressive phenotype.

The sirtuin family in cancer

Sirtuins are a family of protein deacylases and ADP-ribosyl-transferases, homologs to the yeast SIR2 protein. Seven sirtuin paralogs have been described in mammals, with different subcellular locations, targets, enzymatic activities, and regulatory mechanisms. All sirtuins share NAD+ as substrate, placing them as central metabolic hubs with strong relevance in lifespan, metabolism, and cancer development. Much effort has been devoted to studying the roles of sirtuins in cancer, providing a wealth of data on sirtuins roles in mouse models and humans. Also, extensive data are available on the effects of pharmacological modulation of sirtuins in cancer development. Here, we present a comprehensive and organized resume of all the existing evidence linking every sirtuin with cancer development. From our analysis, we conclude that sirtuin modulation after tumor initiation results in unpredictable outcomes in most tumor types. On the contrary, all genetic and pharmacological models indicate that sirtuins activation prior to tumor initiation can constitute a powerful preventive strategy.

Increased Expression of Serine Hydroxymethyltransferase 2 (SHMT2) is a Negative Prognostic Marker in Patients with Hepatocellular Carcinoma and is Associated with Proliferation of HepG2 Cells

Background

Serine hydroxymethyltransferase 2 (SHMT2) is a key enzyme in one-carbon cell metabolism, including in liver cancer. However, the associations between SHMT2 expression at the gene and protein level and prognosis in patients with hepatocellular carcinoma (HCC) remains unknown. This study aimed to investigate the expression levels of SHMT2 in tumor tissue samples from patients with HCC and clinical outcome and the effects of silencing the expression of the SHMT2 gene in HepG2 cells.

Material/Methods

Expression levels of SHMT2 were evaluated in 144 cases of HCC using immunohistochemistry and correlated with clinicopathological factors using the chi-squared (χ²) test. The prognostic significance of SHMT2 expression was analyzed by univariate analysis and multivariate analysis. Twenty pairs of HCC tissue and adjacent normal liver tissue were compared for SHMT2 expression levels using quantitative reverse transcription polymerase chain reaction (qRT-PCR). HepG2 cells underwent SHMT2 gene silencing and MTT and transwell assays investigated cell proliferation and migration. Western blot was used to detect the expression of markers of epithelial-mesenchymal transition (EMT).

Results

Expression levels of SHMT2 in HCC tissues were significantly correlated with tumor grade and hepatitis B virus (HBV) infection, and increased expression was an independent negative prognostic factor in patients with HCC (P=0.003). Increased expression of the SHMT2 gene promoted the proliferation and migration of the HepG2 HCC cell line.

Conclusions

Increased expression of SHMT2 was a negative prognostic biomarker in patients with HCC. Expression of the SHMT2 gene promoted the proliferation and migration of HepG2 HCC cells.