SHMT1 C1420T polymorphism contributes to the risk of non-Hodgkin lymphoma: evidence from 7309 patients

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.

Targeting serine-glycine-one-carbon metabolism as a vulnerability in cancers

The serine-glycine-one-carbon (SGOC) metabolic pathway is critical for DNA methylation, histone methylation, and redox homeostasis, in addition to protein, lipid, and nucleotide biosynthesis. The SGOC pathway is a crucial metabolic network in tumorigenesis, wherein the outputs are required for cell survival and proliferation and are particularly likely to be co-opted by aggressive cancers. SGOC metabolism provides an integration point in cell metabolism and is of crucial clinical significance. The mechanism of how this network is regulated is the key to understanding tumor heterogeneity and overcoming the potential mechanism of tumor recurrence. Herein, we review the role of SGOC metabolism in cancer by focusing on key enzymes with tumor-promoting functions and important products with physiological significance in tumorigenesis. In addition, we introduce the ways in which cancer cells acquire and use one-carbon unit, and discuss the recently clarified role of SGOC metabolic enzymes in tumorigenesis and development, as well as their relationship with cancer immunotherapy and ferroptosis. The targeting of SGOC metabolism may be a potential therapeutic strategy to improve clinical outcomes in cancers.

The C-Reactive Protein to Albumin Ratio Is an Independent Prognostic Factor in Patients with Hepatocellular Carcinoma Undergoing Transarterial Chemoembolization: A Large Cohort Study

BACKGROUND

This study aimed to investigate the prognostic value of C-reactive protein to albumin ratio (CAR) in hepatocellular carcinoma (HCC) patients after transcatheter chemoembolization (TACE).

METHODS

Totally, 958 HCC patients with Barcelona Clinic Liver Cancer (BCLC) stage B were incorporated into the secondary analysis. X-Tile software was applied to determine the optimal cutoff point for CAR, and the total patients were divided into two groups. Cox proportional hazard regression models and Kaplan-Meier analyses were used to estimate the relationship between CAR and overall survival (OS). Stratified analyses were performed to evaluate the prognostic role of CAR in subgroups of major confounding factors, such as alpha-fetoprotein (AFP), diameter of the main tumor, Glasgow prognostic score (GPS) and modified GPS (mGPS).

RESULTS

The optimal cutoff level for the CAR was 0.06. There was a direct correlation between an elevated CAR (≥ 0.06) and shorter OS after adjustment (HR:1.580; 95%CI:1.193-2.092). Kaplan-Meier analysis and log-rank test showed a significant difference in OS curves between the two groups (P < 0.001). CAR showed the distinct value of prognostic stratification in most subgroups, especially in the subgroup of GPS-0 (HR:1.966; 95%CI:1.453-2.660), mGPS-0 (HR:1.984; 95%CI:1.509-2.608) and AFP ≤ 400 ng/ml (HR:1.925; 95%CI:1.393-2.659).

CONCLUSION

The CAR was one of the prognostic factors for HCC patients undergoing TACE treatment. CAR could also provide further prognostic stratification for HCC patients who appear to have a good prognosis, such as patients with AFP-negative, GPS-0 or mGPS-0 to identify patients at a higher risk of death for closer follow-up or more aggressive treatment.

LEVEL OF EVIDENCE

Level 3, Cohort Study.

Genetic variations as molecular diagnostic factors for idiopathic male infertility: current knowledge and future perspectives

INTRODUCTION

Infertility is a major health problem, worldwide, which affects 10-15% of couples. About half a percent of infertility cases are related to male-related factors. Male infertility is a complex disease that is the result of various insults as lifestyle issues, genetics, and epigenetic factors. Idiopathic infertility is responsible for 30% of total cases. The genetic factors responsible for male infertility include chromosomal abnormalities, deletions of chromosome Y, and mutations and genetic variations of key genes.

AREAS COVERED

In this review article, we aim to narrate performed studies on polymorphisms of essential genes involved in male infertility including folate metabolizing genes, oxidative stress-related genes, inflammation, and cellular pathways related to spermatogenesis. Moreover, possible pathophysiologic mechanisms responsible for genetic polymorphisms are discussed.

EXPERT OPINION

Analysis and assessment of these genetic variations could help in screening, diagnosis, and treatment of idiopathic male infertility.

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.

ERVs-TLR3-IRF axis is linked to myelodysplastic syndrome pathogenesis

Toll-like receptors are mutated or overexpressed in up to 50% of patients with myelodysplastic syndrome (MDS). Endogenous retroviruses (ERV) trigger TLR3 leading to interferon regulatory genes (IRFs) activation. We evaluated if the ERVs-TLR3-IRF axis activation would be linked to MDS pathogenesis and we also conducted a detailed cancer analysis of the ERVs, TLR3 and IRFs gene expression in 30 cancer types using GEPIA database. Seventy-nine bone marrow samples from patients with MDS were evaluated for cytogenetics and quantitative real‑time PCR of TLR3, ERVK6, ERVW-1, ERV3-1, IRF3 and IRF7. Patients with dyserythropoiesis showed higher TLR3 (p = 0.035), ERVK6 (p = 0.001), ERVW1 (p = 0.045) and ERV3-1 (p = 0.016) expression than patients without dyserythropoiesis. Upregulation of Interferon Regulatory Factors, IRF3 and IRF7, was associated with poor prognostic markers in MDS such as > 10% of blasts (p = 0.003-IRF3; p = 0.009-IRF7), low platelets count (< 50.000/mm³) (p = 0.001-IRF3; p = 0.021-IRF7), transfusion dependence (p = 0.014-IRF3) and chromosomal abnormalities (p = 0.036-IRF7). We found strong correlations between ERVK6-ERVW1 (r = 0.800; r² = 0.640; p = 0.000), ERVW1-ERV3-1 (r = 0.715; r² = 0.511; p = 0.000), and IRF7-IRF3 (r = 0.567; r² = 0.321; p = 0.000) and moderate correlation between ERVK6-ERV3-1(r = 0.485; r² = 0.235; p = 0.000), ERVW1-IRF7 (r = 0.389; r² = 0.151; p = 0.001), ERVW1-IRF3 (r = 0.357; r² = 0.127; p = 0.004), ERV3-1-IRF7 (r = 0.314; r² = 0.098; p = 0.009), and ERV3-1-IRF3 (r = 0.324; r² = 0.104; p = 0.007). Using GEPIA Database in 30 cancer types, we detected a typical pattern of upregulation as here presented in MDS. We suggest TLR3 activation by ERVs is linked to MDS pathogenesis leading to bone marrow failure. Abnormal double-stranded RNA (dsRNA) expression of Endogenous Retroviruses (ERV) triggers TLR3 hyperactivation. This induces IRF3, IRF7, and NF-kB to translocate to the nucleus and activate transcription of IFNα/β which binds to the type I-IFN receptor promoting interferon response. Thus, just as TLR4 induces a crucial myeloid shift, the ERVs-TLR3 axis may play an important role in establishing one of the most striking characteristics in MDS, dyserythropoiesis.

Evaluation of LKB1 and Serine-Glycine Metabolism Pathway Genes (SHMT1 and GLDC) Expression in AML

LKB1 is a significant tumor suppressor and epigenetic regulator playing a vital role in different types of cancers. SHMT1 and GLDC are two critical genes of the epigenetic pathway influenced by LKB1. As epigenetic is the major cause of AML pathogenesis, this study aimed at investigating LKB1, SHMT1, and GLDC gene expression levels in acute myeloid leukemia patients. The present study was conducted on LKB1, SHMT1, and GLDC gene expression levels in 60 de novo AML samples and 30 normal controls using real-time RT-PCR. The results showed that LKB1 and SHMT1 have respectively a significantly lower (P < 0.05) and higher (P < 0.05) expression level than that of normal controls. Furthermore, the correlation between LKB1 with SHMT1 and GLDC was significant and positive (P value: 0.015, r: 0.299). Positive findings confirm that metabolic pathways alongside the LKB1 association drive the epigenetic axis and its substrate production. Therefore, it can be concluded that the newly-discovered pathway in the pathogenesis of this disease provides new insights into the design of therapeutic targets.

Folate and Its Impact on Cancer Risk

PURPOSE OF REVIEW

Research has evaluated the potential impact of folate on cancer risk with conflicting findings. Studies have demonstrated increased risk, no effect, and decreased risk. This review summarizes findings of mixed results between folate intake, serum levels, gene polymorphisms, and cancer risk based on meta-analyses from the past five years.

RECENT FINDING

Low or deficient folate status is associated with increased risk of many cancers. Folic acid supplementation and higher serum levels are associated with increased risk of prostate cancer. Gene polymorphisms may impact risk in certain ethnic groups. Folate has been studied extensively due to its role in methylation and nucleotide synthesis. Further prospective studies are needed to clarify optimal levels for nutrient remediation and risk reduction in those at risk, as well as elucidate the association between high intake, high serum levels, and prostate cancer risk. Future considerations for cancer risk may include gene interactions with nutrients and environmental factors.

Serine hydroxymethyl transferase 1 stimulates pro-oncogenic cytokine expression through sialic acid to promote ovarian cancer tumor growth and progression

High-grade serous (HGS) ovarian cancer accounts for 90% of all ovarian cancer-related deaths. However, factors that drive HGS ovarian cancer tumor growth have not been fully elucidated. In particular, comprehensive analysis of the metabolic requirements of ovarian cancer tumor growth has not been performed. By analyzing The Cancer Genome Atlas mRNA expression data for HGS ovarian cancer patient samples, we observed that six enzymes of the folic acid metabolic pathway were overexpressed in HGS ovarian cancer samples compared with normal ovary samples. Systematic knockdown of all six genes using short hairpin RNAs (shRNAs) and follow-up functional studies demonstrated that serine hydroxymethyl transferase 1 (SHMT1) was necessary for ovarian cancer tumor growth and cell migration in culture and tumor formation in mice. SHMT1 promoter analysis identified transcription factor Wilms tumor 1 (WT1) binding sites, and WT1 knockdown resulted in reduced SHMT1 transcription in ovarian cancer cells. Unbiased large-scale metabolomic analysis and transcriptome-wide mRNA expression profiling identified reduced levels of several metabolites of the amino sugar and nucleotide sugar metabolic pathways, including sialic acid N-acetylneuraminic acid (Neu5Ac), and downregulation of pro-oncogenic cytokines interleukin-6 and 8 (IL-6 and IL-8) as unexpected outcomes of SHMT1 loss. Overexpression of either IL-6 or IL-8 partially rescued SHMT1 loss-induced tumor growth inhibition and migration. Supplementation of culture medium with Neu5Ac stimulated expression of IL-6 and IL-8 and rescued the tumor growth and migratory phenotypes of ovarian cancer cells expressing SHMT1 shRNAs. In agreement with the ovarian tumor-promoting role of Neu5Ac, treatment with Neu5Ac-targeting glycomimetic P-3Fax-Neu5Ac blocked ovarian cancer growth and migration. Collectively, these results demonstrate that SHMT1 controls the expression of pro-oncogenic inflammatory cytokines by regulating sialic acid Neu5Ac to promote ovarian cancer tumor growth and migration. Thus, targeting of SHMT1 and Neu5Ac represents a precision therapy opportunity for effective HGS ovarian cancer treatment.

Association of the MDM2 SNP285 Polymorphism with Cancer Susceptibility: A Meta-Analysis

The mouse double minute 2 (MDM2) gene encodes a negative regulator for p53, and the polymorphism SNP285 in the promoter region of MDM2 gene has been implicated in cancer risk, but individual published studies had inconclusive results. Therefore, we performed this meta-analysis to obtain a more precise estimation between MDM2 SNP285 polymorphism and risk of cancer. A systematic literature search was performed using the PubMed, Embase, and Chinese Biomedical (CBM) databases. Ultimately, 16 published studies comprising 14,573 cases and 9,115 controls were included. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the strength of associations. Overall, MDM2 SNP285 polymorphism was significantly associated with a decreased overall cancer risk with the heterozygous model (OR = 0.89, 95% CI = 0.79-0.99), and reduced ORs were observed with other genetic models (dominant: OR = 0.90, 95% CI = 0.79-1.01 and allele comparison: OR = 0.91, 95% CI = 0.80-1.03) but not reaching statistical significance. Stratification analysis indicated a decreased risk for ovarian cancer, Caucasians, and studies with relatively large sample size. Despite some limitations, this meta-analysis indicated that the MDM2 SNP285 polymorphism was associated with a decreased cancer risk, which warrants further validation in large and well-designed studies.