Serine Hydroxymethyltransferase 2 Expression Research Articles

Structural Characterization of 5-Substituted Pyrrolo[3,2-d]pyrimidine Antifolate Inhibitors in Complex with Human Serine Hydroxymethyl Transferase 2.

We previously discovered first-in-class multitargeted 5-substituted pyrrolo[3,2-d]pyrimidine antifolates that inhibit serine hydroxymethyltransferase 2 (SHMT2), resulting in potent in vitro and in vivo antitumor efficacies. In this report, we present crystallographic structures for SHMT2 in complex with an expanded series of pyrrolo[3,2-d]pyrimidine compounds with variations in bridge length (3-5 carbons) and the side chain aromatic ring (phenyl, thiophene, fluorine-substituted phenyl, and thiophene). We evaluated structural features of the inhibitor-SHMT2 complexes and correlations to inhibitor potencies (i.e., Kis), highlighting conserved polar contacts and identifying 5-carbon bridge lengths as key determinants of inhibitor potency. Based on the analysis of SHMT2 structural data, we investigated the impact of mutation of Tyr105 in SHMT2 kinetic analysis and studies with HCT116 cells with inducible expression of wild-type and Y105F SHMT2. Increased enzyme inhibition potency by the pyrrolo[3,2-d]pyrimidine inhibitors with Phe105 SHMT2 accompanied an increased growth inhibition of Phe105-expressing HCT116 cells compared to wild-type SHMT2. Pyrrolo[3,2-d]pyrimidine inhibitors with polyglutamate modifications were evaluated for potencies against SHMT2. We determined the crystal structures of SHMT2 in complex with our lead antifolate AGF347 lacking L-glutamate, or as a diglutamate and triglutamate, for comparison with parent AGF347. These data provide the first insights into the influence of antifolate polyglutamylation on SHMT2:inhibitor interactions. Collectively, our results provide new insights into the critical structural determinants of SHMT2 binding by pyrrolo[3,2-d]pyrimidine inhibitors as novel antitumor agents, as well as the first structural characterization of human SHMT2 in complex with polyglutamates of an SHMT2-targeted antifolate.

SHMT2 promotes papillary thyroid cancer metastasis through epigenetic activation of AKT signaling

Cancer cells alter their metabolism and epigenetics to support cancer progression. However, very few modulators connecting metabolism and epigenetics have been uncovered. Here, we reveal that serine hydroxymethyltransferase-2 (SHMT2) generates S-adenosylmethionine (SAM) to epigenetically repress phosphatase and tensin homolog (PTEN), leading to papillary thyroid cancer (PTC) metastasis depending on activation of AKT signaling. SHMT2 is elevated in PTC, and is associated with poor prognosis. Overexpressed SHMT2 promotes PTC metastasis both in vitro and in vivo. Proteomic enrichment analysis shows that AKT signaling is activated, and is positively associated with SHMT2 in PTC specimens. Blocking AKT activation eliminates the effects of SHMT2 on promoting PTC metastasis. Furthermore, SHMT2 expression is negatively associated with PTEN, a negative AKT regulator, in PTC specimens. Mechanistically, SHMT2 catalyzes serine metabolism and produces activated one-carbon units that can generate SAM for the methylation of CpG islands in PTEN promoter for PTEN suppression and following AKT activation. Importantly, interference with PTEN expression affects SHMT2 function by promoting AKT signaling activation and PTC metastasis. Collectively, our research demonstrates that SHMT2 connects metabolic reprogramming and epigenetics, contributing to the poor progression of PTC.

The expression and clinical significance of serine hydroxymethyltransferase2 in gastric cancer.

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. 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. 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. 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.

Hypoxia-induced SHMT2 protein lactylation facilitates glycolysis and stemness of esophageal cancer cells.

Esophageal cancer (EC) is a familiar digestive tract tumor with highly lethal. The hypoxic environment has been demonstrated to be a significant factor in modulating malignant tumor progression and is strongly associated with the abnormal energy metabolism of tumor cells. Serine hydroxymethyl transferase 2 (SHMT2) is one of the most frequently expressed metabolic enzymes in human malignancies. The study was designed to investigate the biological functions and regulation mechanisms of SHMT2 in EC under hypoxia. We conducted RT-qPCR to assess SHMT2 levels in EC tissues and cells (TE-1 and EC109). EC cells were incubated under normoxia and hypoxia, respectively, and altered SHMT2 expression was evaluated through RT-qPCR, western blot, and immunofluorescence. The biological functions of SHMT2 on EC cells were monitored by performing CCK-8, EdU, transwell, sphere formation, glucose uptake, and lactate production assays. The SHMT2 protein lactylation was measured by immunoprecipitation and western blot. In addition, SHMT2-interacting proteins were analyzed by bioinformatics and validated by rescue experiments. SHMT2 was notably upregulated in EC tissues and cells. Hypoxia elevated SHMT2 protein expression, augmenting EC cell proliferation, migration, invasion, stemness, and glycolysis. In addition, hypoxia triggered lactylation of the SHMT2 protein and enhanced its stability. SHMT2 knockdown impeded the malignant phenotype of EC cells. Further mechanistic studies disclosed that SHMT2 is involved in EC progression by interacting with MTHFD1L. Hypoxia-induced SHMT2 protein lactylation and upregulated its protein level, which in turn enhanced MTHFD1L expression and accelerated the malignant progression of EC cells.

MiR-383-5p inhibits the proliferation and migration of lung adenocarcinoma cells by targeting SHMT2.

Purpose: To explore the effects of miR-383-5p and serine hydroxymethyltransferase 2 (SHMT2) on the proliferation and migration of lung adenocarcinoma cells. Methods: SHMT2 expression in lung adenocarcinoma and normal tissues was investigated using The Cancer Genome Atlas database. Immunohistochemical analysis was performed to confirm SHMT2 expression in lung adenocarcinoma and adjacent normal lung tissues. Bioinformatics analysis and luciferase reporter assays were used to analyze the relationship between miR-383-5p and SHMT2 expression. The protein expression levels of SHMT2, vimentin, N-cadherin, E-cadherin, Bcl-2, and cyclinD1 were analyzed using western blotting. The reverse transcription-quantitative polymerase chain reaction was used to detect SHMT2 knockdown efficiency, miR-383-5p overexpression, and inhibition efficiency. The proliferative ability of cells was detected using the Cell Counting Kit-8 assay. The Transwell assay was used to detect the migration ability of cells. Results: SHMT2 expression was significantly increased in patients with lung adenocarcinoma compared to that in control patients; the higher the SHMT2 expression the worse the outcomes were in patients with lung adenocarcinoma. SHMT2 knockdown inhibited the proliferation, migration, and epithelial-mesenchymal transition of lung adenocarcinoma A549 and H1299 cells. MiR-383-5p directly targeted and downregulated SHMT2 in A549 and H1299 cells. The effects of miRNA-383-5p on the proliferation and migration of these cells differed from those of SHMT2. Exogenous overexpression of SHMT2 reversed the miR-383-5p-induced proliferation and migration inhibition in A549 and H1299 cells. Conclusion: MiR-383-5p inhibits the proliferation and migration of lung adenocarcinoma cells by targeting and downregulating SHMT2.

SHMT2 regulates esophageal cancer cell progression and immune Escape by mediating m6A modification of c-myc

BackgroundIn recent years, the role of altered cellular metabolism in tumor progression has attracted widespread attention. Related metabolic enzymes have also been considered as potential cancer therapeutic targets. Serine hydroxymethyltransferase 2 (SHMT2) has been reported to be upregulated in several cancers and associated with poor prognosis. However, there are few studies of SHMT2 in esophageal cancer (EC), and the related functions and mechanisms also need to be further explored.MethodsIn this study, we first analyzed SHMT2 expression in EC by online database and clinical samples. Then, the biological functions of SHMT2 in EC were investigated by cell and animal experiments. The intracellular m6A methylation modification levels were also evaluated by MeRIP. Linked genes and mechanisms of SHMT2 were analyzed by bioinformatics and rescue experiments.ResultsWe found that SHMT2 expression was abnormally upregulated in EC and associated with poor prognosis. Functionally, SHMT2 silencing suppressed c-myc expression in an m6A-dependent manner, thereby blocking the proliferation, migration, invasion and immune escape abilities of EC cells. Mechanistically, SHMT2 encouraged the accumulation of methyl donor SAM through a one-carbon metabolic network, thereby regulating the m6A modification and stability of c-myc mRNA in a METTL3/FTO/ALKBH5/IGF2BP2-dependent way. In vivo animal experiments also demonstrated that SHMT2 mediated MYC expression by m6A-methylation modification, thus boosting EC tumorigenesis.ConclusionIn conclusion, our data illustrated that SHMT2 regulated malignant progression and immune escape of EC cell through c-myc m6A modification. These revealed mechanisms related to SHMT2 in EC and maybe offer promise for the development of new therapeutic approaches.

NFYB increases chemosensitivity in glioblastoma by promoting HDAC5-mediated transcriptional inhibition of SHMT2.

Temozolomide (TMZ) is a commonly used chemotherapeutic agent for glioblastoma (GBM), but acquired drug resistance prevents its therapeutic efficacy. We investigated potential mechanisms underlying TMZ resistance and glycolysis in GBM cells through regulation by nuclear transcription factor Y subunit β (NFYB) of the oncogene serine hydroxymethyltransferase 2 (SHMT2). GBM U251 cells were transfected with NFYB-, SHMT2-, and the potential NFYB target histone deacetylase 5 (HDAC5)-related vectors. Glucose uptake and lactate production were measured with detection kits. CCK-8/colony formation, scratch, Transwell, and flow cytometry assays were performed to detect cell proliferation, migration, invasion, and apoptosis, respectively. The binding of NFYB to the HDAC5 promoter and the regulation of NFYB on HDAC5 promoter activity were detected with chromatin immunoprecipitation and dual-luciferase reporter assays, respectively. NFYB and HDAC5 were poorly expressed and SHMT2 was expressed at high levels in GBM U251 cells. NFYB overexpression or SHMT2 knockdown decreased glucose uptake, lactate production, proliferation, migration, and invasion and increased apoptosis and TMZ sensitivity of the cells. NFYB activated HDAC5 to inhibit SHMT2 expression. SHMT2 overexpression nullified the inhibitory effects of NFYB overexpression on glycolysis and TMZ resistance. Thus, NFYB may reduce tumorigenicity and TMZ resistance of GBM through effects on the HDAC5/SHMT2 axis.

SHMT2 Promotes Gastric Cancer Development through Regulation of HIF1α/VEGF/STAT3 Signaling.

The metabolic enzymes involved in one-carbon metabolism are closely associated with tumor progression and could be potential targets for cancer therapy. Recent studies showed that serine hydroxymethyltransferase 2 (SHMT2), a crucial enzyme in the one-carbon metabolic pathway, plays a key role in tumor proliferation and development. However, the precise role and function of SHMT2 in gastric cancer (GC) remain poorly understood. In this study, we presented evidence that SHMT2 was necessary for hypoxia-inducible factor-1α (HIF1α) stability and contributed to GC cells' hypoxic adaptation. The analysis of datasets retrieved from The Cancer Genome Atlas and the experimentation with human cell lines revealed a marked increase in SHMT2 expression in GC. The SHMT2 knockdown in MGC803, SGC7901, and HGC27 cell lines inhibited cell proliferation, colony formation, invasion, and migration. Notably, SHMT2 depletion disrupted redox homeostasis and caused glycolytic function loss in GC cells under hypoxic circumstances. Mechanistically, we discovered SHMT2 modulated HIF1α stability, which acted as a master regulator of hypoxia-inducible genes under hypoxic conditions. This, in turn, regulated the downstream VEGF and STAT3 pathways. The in vivo xenograft experiments showed that SHMT2 knockdown markedly reduced GC growth. Our results elucidate the novel function of SHMT2 in stabilizing HIF1α under hypoxic conditions, thus providing a potential therapeutic strategy for GC treatment.

Exosome-mediated transfer of circ_0063526 enhances cisplatin resistance in gastric cancer cells via regulating miR-449a/SHMT2 axis.

Exosomes are critical mediators of intercellular communication. Exosomal circular RNAs (circRNAs) have been reported to play critical roles in the development of chemoresistance in various tumors, including gastric cancer. However, the role of exosomal circ_0063526 in cisplatin (CDDP) resistance of gastric cancer is still unclear. The expression of circ_0063526, microRNA-449a (miR-449a) and serine hydroxymethyltransferase 2 (SHMT2) mRNA was determined by quantitative real-time PCR (qRT-PCR). Cell viability was assessed by the Cell Counting Kit-8 assay. Cell migration and invasion were evaluated by the transwell assay and wound healing assay. Western blot assay was used to measure the protein expression of light Chain 3 (LC3) I/II, p62 and SHMT2. Exosomes were detected using transmission electron microscopy. The size distribution of exosomes was analyzed by nanoparticle tracking analysis. The interaction between miR-449a and circ_0063526 or SHMT2 was confirmed by a dual-luciferase reporter and RNA pull-down assays. Circ_0063526 expression was increased in gastric cancer tissues and cells and CDDP-resistant cells. Extracellular circ_0063526 could be packaged into exosomes and transmitted to sensitive cells, thus disseminating CDDP resistance. Knockdown of exosomal circ_0063526 inhibited CDDP resistance via suppressing migration, invasion and autophagy in gastric cancer cells. Moreover, circ_0063526 was identified as a molecular sponge of miR-449a to upregulate SHMT2 expression. Further, exosomal circ_0063526 regulated SHMT2 expression to enhance CDDP resistance of gastric cancer cells. Additionally, high expression of exosomal circ_0063526 in serum was associated with poor response to CDDP treatment in gastric cancer patients. Exosomal circ_0063526 facilitated CDDP resistance in gastric cancer via regulating the miR-449a/SHMT2 axis.

SHMT2 Induces Stemness and Progression of Head and Neck Cancer.

Various enzymes in the one-carbon metabolic pathway are closely related to the development of tumors, and they can all be potential targets for cancer therapy. Serine hydroxymethyltransferase2 (SHMT2), a key metabolic enzyme, is very important for the proliferation and growth of cancer cells. However, the function and mechanism of SHMT2 in head and neck cancer (HNC) are not clear. An analysis of The Cancer Genome Atlas (TCGA) data showed that the expression of SHMT2 was higher in tumor tissue than in normal tissue, and its expression was significantly associated with male sex, aggressive histological grade, lymph node metastasis, distant metastasis, advanced TNM stage, and lymphovascular invasion in HNC. SHMT2 knockdown in FADU and SNU1041 cell lines significantly inhibited cell proliferation, colony formation, migration, and invasion. Additionally, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses using TCGA data revealed that SHMT2 was closely related to cancer stem cell regulation and maintenance. Furthermore, we found that silencing SHMT2 inhibited the expression of stemness markers and tumor spheroid formation compared with a control group. On the contrary, stemness markers were significantly increased after SHMT2 overexpression in HEP-2 cells. Interestingly, we found that knocking down SHMT2 reduced the expression of genes related to the Notch and Wnt pathways. Finally, silencing SHMT2 significantly reduced tumor growth and decreased stemness markers in a xenograft model. Taken together, our study suggests that targeting SHMT2 may play an important role in inhibiting HNC progression.

Downregulation of SHMT2 promotes the prostate cancer proliferation and metastasis by inducing epithelial-mesenchymal transition

Serine hydroxymethyltransferase 2 (SHMT2) is a key enzyme that regulates serine/glycine transition; however, its specific function and molecular mechanisms in tumors remain controversial. In this study, we aimed to enhance the understanding in this regard. Through in vitro and in vivo experiments, as well as data analyses using public databases, we investigated the effect of SHMT2 in prostate cancer. Our results indicated that SHMT2 acts as a prostate cancer tumor proliferation suppressor and negatively regulates the aggressive behavior of prostate cancer through activation of epithelial–mesenchymal transition. Additionally, downregulated SHMT2 expression was observed in more advanced prostate cancer phenotypes, and further analysis showed that its depletion promoted proliferation and migration in prostate cancer cell lines. Taken together, our results revealed the function of SHMT2 in prostate cancer and may potentially play a role in the exploration of new therapeutic strategies.

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

ABSTRACT 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.

SHMT2 Drives the Progression of Colorectal Cancer by Regulating UHRF1 Expression.

Introduction Serine hydroxymethyltransferase 2 (SHMT2) has a critical role in serine-glycine metabolism to drive cancer cell proliferation. Yet, the function of SHMT2 in tumorigenesis, especially in human colorectal cancer (CRC) progression, remains largely unclear. Materials and Methods CRC and paired normal samples were collected in the Department of Colorectal Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, and assessed by real-time polymerase chain reaction (qPCR) analysis, western blot (WB), and immunohistochemistry (IHC). Moreover, SHMT2 expression in human CRC cells was identified by qPCR and WB. The CRC cell proliferation, migration, and invasion after SHMT2 knockdown were explored through in vitro and in vivo assays. mRNA-seq assays were used to investigate the underlying mechanisms behind the SHMT2 function. Results It was found that SHMT2 mRNA and protein were overexpressed in CRC tissue compared to the levels in normal mucosa. Positive expression of SHMT2 was significantly correlated with TNM stage and lymph node metastasis, and elevated expression of SHMT2 resulted as an independent prognostic factor in patients with CRC. SHMT2 knockdown impaired the proliferation of CRC in vitro and in vivo and induced cell cycle arrest by regulating UHRF1 expression. Conclusion Taken together, our findings reveal that UHRF1 is a novel target gene of SHMT2, which can be used as a potential therapeutic strategy for CRC therapy.

Induction of serine hydroxymethyltransferase 2 promotes tumorigenesis and metastasis in neuroblastoma.

High-risk neuroblastoma (NB) remains an extremely difficult subgroup to cure and is associated with MYCN amplification. Serine hydroxymethyltransferase 2 (SHMT2) regulates serine metabolism in a myc-dependent manner; it is upregulated in several cancers and is associated with tumor aggressiveness. Akt-2, an important regulator of MYCN via the PI3K/Akt pathway, induces metastatic potential in NB. The association between SHMT2 and PI3K/Akt in hepatocyte regeneration has been well established but its mechanistic interaction in cancer has yet to be clearly elucidated. Herein, we evaluated the exact role of SHMT2 on the PI3K/Akt pathway, in addition to NB tumorigenesis and metastatic potential in vitro. SHMT2 gene expression and overall survival (OS) were assessed. Two human NB cell lines were examined. SHMT2 silencing and overexpression were performed. The downstream effects were analyzed with immunoblotting, RT-qPCR and functional assays were performed. We found SHMT2 gene expression is associated with decreased OS and MYCN amplification. SHMT2 protein and mRNA expression are increased in MYCN-amplified cells. SHMT2 expression has a direct interaction with Akt-2 and MYCN. Induction of SHMT2 increased cellular proliferation, colony formation and cellular migration and SHMT2 expression was increased in metastatic NB cells. We conclude that SHMT2 regulates N-Myc via phosphorylation of Akt-2 and plays an important role in NB tumorigenesis by contributing to cell growth, migration, colony formation and metastasis in vitro.

Serine hydroxymethyltransferase 2 expression promotes tumorigenesis in rhabdomyosarcoma with 12q13-q14 amplification.

The 12q13-q14 chromosomal region is recurrently amplified in 25% of fusion-positive (FP) rhabdomyosarcoma (RMS) cases and is associated with a poor prognosis. To identify amplified oncogenes in FP RMS, we compared the size, gene composition, and expression of 12q13-q14 amplicons in FP RMS with those of other cancer categories (glioblastoma multiforme, lung adenocarcinoma, and liposarcoma) in which 12q13-q14 amplification frequently occurs. We uncovered a 0.2 Mb region that is commonly amplified across these cancers and includes CDK4 and 6 other genes that are overexpressed in amplicon-positive samples. Additionally, we identified a 0.5 Mb segment that is only recurrently amplified in FP RMS and includes 4 genes that are overexpressed in amplicon-positive RMS. Among these genes, only serine hydroxymethyltransferase 2 (SHMT2) was overexpressed at the protein level in an amplicon-positive RMS cell line. SHMT2 knockdown in amplicon-positive RMS cells suppressed growth, transformation, and tumorigenesis, whereas overexpression in amplicon-negative RMS cells promoted these phenotypes. High SHMT2 expression reduced sensitivity of FP RMS cells to SHIN1, a direct SHMT2 inhibitor, but sensitized cells to pemetrexed, an inhibitor of the folate cycle. In conclusion, our study demonstrates that SHMT2 contributes to tumorigenesis in FP RMS and that SHMT2 amplification predicts differential response to drugs targeting this metabolic pathway.

Abstract 1992: Serine hydroxymethyltransferase-2 as regulator of oxidative stress and chemoradiation resistance in lung adenocarcinoma

Abstract Purpose/Objective(s): Lung cancer is the leading cause of cancer deaths in the United States and worldwide. There has been little improvement in survival over the past several decades and surgery is generally considered to be the only curative treatment. We, therefore, performed a genome-wide functional genomics screen on human lung adenocarcinoma cells to identify genes involved in chemo- and radiotherapy resistance. Based on these results, we hypothesized that serine hydroxymethyltransferase-2 (SHMT2), which catalyzes the conversion of serine to glycine, is a target for chemoradiotherapy resistance in preclinical models of lung adenocarcinoma. Materials/Methods: PC9 cells were treated three times with 1 uM cisplatin and 2 Gy radiation before being subjected to genomic, untargeted metabolomic, or proteomic analysis. For the genomic analysis, PC9 cells were transfected with an shRNA viral library containing ~60,000 individual shRNAs following treatment. shRNAs that were depleted were hypothesized to represent genes involved in chemo-/radioresistance. Proteomics analysis was conducted after treatment and quantified by tandem mass tags isobaric labeling, totaling ~2,100 quantifiable proteins. An untargeted metabolomics approach was conducted after treatment, using gas chromatography mass spectrometry to quantify ~95 metabolites. Protein expression following treatment was determined by Western blot. Potential drug targets were assessed via colony formation assays. The Cancer Genome Atlas (TCGA) was queried to confirm in vivo human clinical correlations. Results: Our genomic, proteomic, and metabolomics screens indicated glutathione detoxification and oxidative stress response were major compensatory pathways upregulated after cisplatin and radiation treatment. We validated three targets, SLC7A11, GPX4, and SHMT2, as genes involved in chemo-radioresistance in vitro. The respective small molecule inhibitors of these gene targets, IKE, RSL3, and SHIN1, were synergistic when combined with cisplatin and radiation. SHIN1 appeared to also induce oxidative stress through ferroptosis, although this mechanism of cell death must be interrogated further. Analysis of TCGA revealed SHMT2 expression is upregulated in human lung adenocarcinoma in vivo and that higher expression is associated with decreased overall and disease-free survival. Conclusion: SHMT2 was identified as a novel target to overcome treatment resistance in human lung adenocarcinoma, which may be regulated ferroptotic cell death. Citation Format: Kunal R. Chaudhary, Connor J. Kinslow, Ling F. Ye, Pavan S. Upadhyayula, Eun Y. Lee, Ramon C. Sun, Simon K. Cheng. Serine hydroxymethyltransferase-2 as regulator of oxidative stress and chemoradiation resistance in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1992.

SHMT2 expression as a diagnostic and prognostic marker for thyroid cancer.

BackgroundCatabolism 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.MethodsThyroid tissue samples and The Cancer Genome Atlas (TCGA) database were used to evaluate SHMT2 expression in thyroid tissues and the association with clinical outcomes.ResultsSHMT2 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).ConclusionSHMT2 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.

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.

Cytoplasmic SHMT2 drives the progression and metastasis of colorectal cancer by inhibiting β-catenin degradation.

Introduction: Serine hydroxymethyltransferase 2 (SHMT2) plays a critical role in serine-glycine metabolism to drive cancer cell proliferation. However, the nonmetabolic function of SHMT2 in tumorigenesis, especially in human colorectal cancer (CRC) progression, remains largely unclear.Methods: SHMT2 expression in human CRC cells was identified by western blot and immunofluorescence assay. The CRC cell proliferation, migration, and invasion after SHMT2 knockdown or overexpression were explored through in vitro and in vivo assays. Immunofluorescence, mRNA-seq, co-immunoprecipitation, chromatin immunoprecipitation-qPCR and immunohistochemistry assays were used to investigate the underlying mechanisms behind the SHMT2 nonmetabolic function.Results: We demonstrated that SHMT2 was distributed in the cytoplasm and nucleus of human CRC cells. SHMT2 knockdown resulted in the significant inhibition of CRC cell proliferation, which was not restored by serine, glycine, or formate supplementation. The invasion and migration of CRC cells were suppressed after SHMT2 knockdown. Mechanistically, SHMT2 interacted with β-catenin in the cytoplasm. This interaction inhibited the ubiquitylation-mediated degradation of β-catenin and subsequently modulated the expression of its target genes, leading to the promotion of CRC cell proliferation and metastasis. Notably, the lysine 64 residue on SHMT2 (SHMT2K64) mediated its interaction with β-catenin. Moreover, transcription factor TCF4 interacted with β-catenin, which in turn increased SHMT2 expression, forming an SHMT2/β-catenin positive feedback loop. In vivo xenograft experiments confirmed that SHMT2 promoted the growth and metastasis of CRC cells. Finally, the level of SHMT2 was found to be significantly increased in human CRC tissues. The SHMT2 level was correlated with an increased level of β-catenin, associated with CRC progression and predicted poor patient survival.Conclusion: Taken together, our findings reveal a novel nonmetabolic function of SHMT2 in which it stabilizes β-catenin to prevent its ubiquitylation-mediated degradation and provide a potential therapeutic strategy for CRC therapy.

Calsyntenin 1 mRNA expression sensitivity to ionizing radiation in human hepatocytes and carcinoma cells and blood cells of BALB/c mice

ABSTRACT Whether calsyntenin 1 (CLSTN1) and serine hydroxymethyltransferase 2 (SHMT2) are sensitive to low-dose ionizing radiation (LDIR) has not yet been defined. Therefore, here, we aimed to investigate changes in gene expression in hepatic cell lines and in blood cells and serum from irradiated mice. Levels of SHMT2 and CLSTN1 were decreased in cancer (HepG2) and normal (HH) hepatocytes exposed to various radiation doses. The mRNA expression of SHMT2 and CLSTN1 was altered in response to 0.5 or 4 Gy of radiation at 24 h post irradiation in vivo. However, plasma SHMT2 protein levels did not change at either radiation dose relative to those in the non-irradiated group. Plasma CLSTN1 protein levels notably decreased in response to 4 Gy of radiation but were not altered in response to 0.5 Gy of radiation. Thus, our findings suggest that the mRNA and protein levels of CLSTN1 might be useful biomarkers for radiation exposure. Further studies are needed to characterize the molecular regulation and functional roles of SHMT2 and CLSTN1 in response to radiation.