Association of Folate and Vitamins Involved in the 1-Carbon Cycle with Polymorphisms in the Methylenetetrahydrofolate Reductase Gene (MTHFR) and Global DNA Methylation in Patients with Colorectal Cancer

Quantification of multi-pathway metabolites related to folate metabolism and application in natural population with MTHFR C677T polymorphism

Folate, serving as a crucial micronutrient, plays an important role in promoting human growth and supporting transformations to a variety of metabolic pathways including one-carbon, pyrimidine, purine, and homocysteine metabolism. The 5,10-methylenetetrahydrofolate reductase (MTHFR) enzyme is pivotal in the folate metabolic pathway. Polymorphism in the MTHFR gene, especially C677T, was associated with decreased enzyme activity and disturbance of folate metabolism, which is linked to various diseases including birth defects in newborns and neural tube abnormalities. However, the detailed metabolic disturbance induced by MTHFR C677T polymorphism is still elusive. In this study, a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the precise quantification of 93 metabolites from six important metabolic pathways related to folate metabolism. The method characteristics demonstrated high accuracy and precision, with r2 values ranging from 0.981 to 1.000 for all metabolites. Then the impact of the MTHFR C677T polymorphism on folate metabolism was further investigated, revealing a significant reduction in the level of 5-methyltetrahydrofolate and abnormal levels of metabolites associated with DNA synthesis pathways in individuals carrying the mutation. These data highlight the pivotal role of folic acid supplementation for individuals with the MTHFR C677T polymorphism to mitigate health risks and show the value of precision measurement of folate-related metabolites.

The use of nutrigenomics and nutritional biomarkers with standard care of long-term recurrent metastatic rectal cancer: a case report

Introduction

Distant metastases following standard treatment for locally advanced rectal cancer (LARC) are typically associated with poor disease-free survival. We report on a 52-year-old Australian male of Dutch ancestry with no family history of colorectal cancer or significant medical history who experienced bleeding per rectum for several months prior to a colonoscopy in July 2010. He was subsequently diagnosed with Stage IIb LARC.

Case presentation

Despite treatment with curative intent, a distant recurrence to his left lung was detected in May 2012, upstaging him to Stage IV rectal cancer. He had repeated distant metastatic recurrences over the next 8 years, and treatment included multiple surgeries, chemotherapies, radiation treatments, a "watch and wait" period of 20 months, and personalised dietary management. Genetic and nutrigenomic testing identified that the case had KRAS and MTHFR mutations. As part of his dietary management, the case also had his levels of folate, vitamin B12, and vitamin D regularly monitored because of his genetic predisposition and history of deficiency for these key nutrients. Apart from changes in his CEA levels, sudden increases in the patient's folate levels, inconsistent with dietary exposures preceded detection of each new distant recurrence, with significant decreases in the levels at the next follow-up measurement.

Conclusion

A multimodal approach to this patient's management appeared to contribute to his long-term survival of nearly 10 years from the initial diagnosis. Multidisciplinary management, including the use of additional biomarkers, may enhance survival rates in other similar cases with advanced disease resistant to differing therapies, and with potentially poor prognosis.

Can Global DNA Methylation Be Influenced by Polymorphisms in Genes Involved in Epigenetic Mechanisms? A Review

BACKGROUND

Global methylation refers to the total methylation in the DNA and can also be inferred from the Line 1 and Alu regions, as these repeats are very abundant in the genome. The main function of DNA methylation is to control gene expression and is associated with both normal and pathological mechanisms. DNA methylation depends on enzymes that generate the methyl radical (e.g., methylenetetrahydrofolate reductase-MTHFR) and attach this radical to the DNA (DNA methyltransferases-DNMT). Genetic variants such as single nucleotide polymorphisms (SNP) in these genes can lead to changes in the activity or expression of MTHFR and DNMT proteins and consequently influence the DNA methylation profile. This review focuses on studies investigating inter-individual variations in the global DNA methylation profile associated with genetic polymorphisms in the MTHFR and DNMT genes.

METHODS

A narrative review was conducted, taking into account articles published in the last 15 years.

RESULTS

It was found that the SNPs rs1801131, rs1801133 and rs1537514 in the MTHFR gene, rs2241531, rs2228611, rs2228612, rs21124724 and the haplotype rs2288349, rs2228611, rs2228612, rs16999593 in the DNMT1 gene, rs2424909, rs998382, rs6058891, rs6058897, rs4911256, rs2889703 and rs1883729 in the DNMT3B were associated with the level of global DNA methylation, including LINE and Alu regions in different contexts. No association was found with polymorphisms in the DNMT3A gene.

CONCLUSIONS

It is concluded that polymorphisms in the MTHFR and DNMT genes may influence the global DNA methylation profile in health, inflammation, tumours and mental illness.

Comparative Analysis of Vitamin D, Folic Acid, and Antioxidant Minerals in Various Stages of Lung Cancer

BACKGROUND

Lung cancer continues to be one of the most common causes of death due to lung malignancies globally. Emerging research suggests that vitamins and trace minerals, particularly antioxidants, may play a role in cancer progression and treatment outcomes. This study conducts a comparative analysis of vitamin D, folic acid, and trace minerals (copper, zinc, and magnesium) in various stages of lung cancer patients.

METHODS

A cross-sectional study was conducted with 160 lung cancer patients, categorized into four stages (Stage 1 to Stage 4). Standardized biochemical assays, such as chemiluminescent immunoassay (CLIA), enzyme-linked immunosorbent assay (ELISA), and atomic absorption spectroscopy (AAS), were used to measure the levels of vitamin D, folic acid, copper (Cu), zinc (Zn), and magnesium (Mg) in the blood. The nutrient levels were compared across stages to investigate any significant variations.

RESULTS

Vitamin D levels decreased significantly as lung cancer progressed, with Stage 1 showing the highest mean level (33 ng/mL) and Stage 4 the lowest (8 ng/mL). Folic acid levels fluctuated, showing a general decrease in the advanced stages, with some variations in the intermediate stages. Copper levels showed individual variability without a consistent trend across stages. Zinc levels were higher in early-stage patients and decreased as cancer progressed. Magnesium levels remained relatively stable across all stages.

CONCLUSION

This comparative analysis highlights the potential significance of monitoring vitamin D, folic acid, and trace minerals in lung cancer patients across different stages. The results suggest that these nutrients may play a role in the progression of lung cancer and could serve as biomarkers for disease staging.

Post-diagnostic multivitamin supplement use and colorectal cancer survival: A prospective cohort study

BACKGROUND

Use of multivitamin supplements has been associated with lower incidence of colorectal cancer (CRC). However, its influence on CRC survival remains unknown.

METHODS

Among 2424 patients with stage I-III CRC who provided detailed information about multivitamin supplements in the Nurses' Health Study and Health Professionals Follow-up Study, the authors calculated multivariable hazard ratios (HRs) of multivitamin supplements for all-cause and CRC-specific mortality according to post-diagnostic use and dose of multivitamin supplements.

RESULTS

During a median follow-up of 11 years, the authors documented 1512 deaths, among which 343 were of CRC. Compared to non-users, post-diagnostic users of multivitamin supplements at a dose of 3-5 tablets/week had lower CRC-specific mortality (HR, 0.55; 95% confidence interval [CI], 0.36-0.83, p = .005), and post-diagnostic users at doses of 3-5 and 6-9 tablets/week had lower all-cause mortality (HR, 0.81; 95% CI, 0.67-0.99, p = .04; HR, 0.79; 95% CI, 0.70-0.88), p < .001). The dose-response analysis showed a curvilinear relationship for both CRC-specific (pnonlinearity < .001) and all-cause mortality (pnonlinearity = .004), with the maximum risk reduction observed at 3-5 tablets/week and no further reduction at higher doses. Compared to non-users in both pre- and post-diagnosis periods, new post-diagnostic users at dose of <10 tablets/week had a lower all-cause mortality (HR, 0.81; 95% CI, 0.71-0.94, p = .005), whereas new users at a dose of ≥10 tablets/week (HR, 1.58; 95% CI, 1.07-2.33) and discontinued users (HR, 1.35; 95% CI, 1.14-1.59) had a higher risk of mortality.

CONCLUSIONS

Use of multivitamin supplements at a moderate dose after a diagnosis of nonmetastatic CRC is associated with lower CRC-specific and overall mortality, whereas a high dose (≥10 tablets/week) use is associated with higher CRC-specific mortality.

Association Between Vitamin B12 Intake and Mortality in Patients with Colorectal Cancer: The US National Health and Nutrition Examination Survey, 1999-2018

Vitamin B12 plays a role in DNA methylation, influencing the 1-carbon cycle; However, its effect on colorectal cancer (CRC) mortality remains uncertain. This study assessed the relationship between vitamin B12 intake and all-cause and cancer-specific mortality among CRC patients. We analyzed data from the NHANES from 1999 to 2018, using multivariable Cox regression, competing risk model, Kaplan-Meier survival curves, and stratified analysis with interaction effects. The studied involved 4,554 cancer patients (mean age 65.8 years, 47.6% males). Results from multivariate Cox regression indicated that each additional 1 mcg/day of dietary vitamin B12 independently increased the risk of all-cause (HR, 1.07; 95% CI: 1.04-1.09, p < 0.001) and cancer-specific mortality (HR, 1.04; 95% CI, 1.02-1.06; p < 0.001). Kaplan-Meier curves indicated a higher risk of all-cause mortality with increased vitamin B12 intake (Log rank p = 0.01). Subgroup analysis suggested that higher vitamin B12 intake correlated with increased all-cause mortality risk, especially in individuals with higher protein (HR, 1.04; 95% CI, 1.02-1.06; p = 0.019) or carbohydrate intake (HR, 1.03; 95% CI, 1.01-1.05; p = 0.04). Thus, higher vitamin B12 intake correlates with increased all-cause and cancer-specific mortality in CRC patients, particularly those with higher protein or carbohydrate intake.

[Impact of Folic Acid on the Resistance of Non-small Cell Lung Cancer Cells to Osimertinib by Regulating Methylation of DUSP1]

BACKGROUND

Drug resistance is the main cause of high mortality of lung cancer. This study was conducted to investigate the effect of folic acid (FA) on the resistance of non-small cell lung cancer (NSCLC) cells to Osimertinib (OSM) by regulating the methylation of dual specificity phosphatase 1 (DUSP1).

METHODS

The OSM resistant NSCLC cell line PC9R was establishd by gradually escalation of OSM concentration in PC9 cells. PC9R cells were randomly grouped into Control group, OSM group (5 μmol/L OSM), FA group (600 nmol/L FA), methylation inhibitor decitabine (DAC) group (10 μmol/L DAC), FA+OSM group (600 nmol/L FA+5 μmol/L OSM), and FA+OSM+DAC group (600 nmol/L FA+5 μmol/L OSM+10 μmol/L DAC). CCK-8 method was applied to detect cell proliferation ability. Scratch test was applied to test the ability of cell migration. Transwell assay was applied to detect cell invasion ability. Flow cytometry was applied to measure and analyze the apoptosis rate of cells in each group. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) method was applied to detect the expression level of DUSP1 mRNA in cells. Methylation specific PCR (MSP) was applied to detect the methylation status of the DUSP1 promoter region in each group. Western blot was applied to analyze the expression levels of DUSP1 protein and key proteins in the DUSP1 downstream mitogen-activated protein kinase (MAPK) signaling pathway in each group.

RESULTS

Compared with the Control group, the cell OD450 values (48 h, 72 h), scratch healing rate, number of cell invasions, and expression of DUSP1 in the OSM group were obviously decreased (P<0.05); the apoptosis rate, the methylation level of DUSP1, the expression of p38 MAPK protein, and the phosphorylation level of extracellular regulated protein kinases (ERK) were obviously increased (P<0.05); the cell OD450 values (48, 72 h), scratch healing rate, number of cell invasions, and expression of DUSP1 in the DAC group were obviously increased (P<0.05); the apoptosis rate, the expression of p38 MAPK protein, the phosphorylation level of ERK, and the methylation level of DUSP1 were obviously reduced (P<0.05). Compared with the OSM group, the cell OD450 values (48, 72 h), scratch healing rate, number of cell invasions, and expression of DUSP1 in the FA+OSM group were obviously decreased (P<0.05); the apoptosis rate, the methylation level of DUSP1, the expression of p38 MAPK protein, and the phosphorylation level of ERK were obviously increased (P<0.05). Compared with the FA+OSM group, the cell OD450 values (48, 72 h), scratch healing rate, number of cell invasions, and expression of DUSP1 in the FA+OSM+DAC group were obviously increased; the apoptosis rate, the methylation level of DUSP1, the expression of p38 MAPK protein, and the phosphorylation level of ERK were obviously reduced (P<0.05).

CONCLUSIONS

FA may inhibit DUSP1 expression by enhancing DUSP1 methylation, regulate downstream MAPK signal pathway, then promote apoptosis, inhibit cell invasion and metastasis, and ultimately reduce OSM resistance in NSCLC cells.

An overview of vitamins as epidrugs for colorectal cancer prevention

Gene expression altering epigenomic modifications such as DNA methylation, histone modification, and chromosome remodeling is crucial to regulating many biological processes. Several lifestyle factors, such as diet and natural, bioactive food compounds, such as vitamins, modify epigenetic patterns. However, epigenetic dysregulation can increase the risk of many diseases, including cancer. Various studies have provided supporting and contrasting evidence on the relationship between vitamins and cancer risk. Though there is a gap in knowledge about whether dietary vitamins can induce epigenetic modifications in the context of colorectal cancer (CRC), the possibility of using them as epidrugs for CRC treatment is being explored. This is promising because such studies might be informative about the most effective way to use vitamins in combination with DNA methyltransferase inhibitors and other approved therapies to prevent and treat CRC. This review summarizes the available epidemiological and observational studies involving dietary, circulating levels, and supplementation of vitamins and their relationship with CRC risk. Additionally, using available in vitro, in vivo, and human observational studies, the role of vitamins as potential epigenetic modifiers in CRC is discussed. This review is focused on the action of vitamins as modifiers of DNA methylation because aberrant DNA methylation, together with genetic alterations, can induce the initiation and progression of CRC. Although this review presents some studies with promising results, studies with better study designs are necessary. A thorough understanding of the underlying molecular mechanisms of vitamin-mediated epigenetic regulation of CRC genes can help identify effective therapeutic targets for CRC prevention and treatment.

Association of MTHFR C677T variant genotype with serum folate and Vit B12 in Iranian patients with colorectal cancer or adenomatous polyps

Background

The incidence of colorectal cancer (CRC) has increased during recent years in Iran and other developing countries. Clinical studies suggest that essential folate dietary intake and moderate deficiency of methylenetetrahydrofolate reductase (MTHFR) may protect and reduce the risk of CRC. The present study aimed to investigate the clinical significance of C677T polymorphism within the MTHFR gene and its correlation with the serum folate and Vit B₁₂ in the Iranian population suffering from CRC.

Methods

Blood samples were taken from 1017 Iranian individuals (517 cases and 500 controls) who were referred for colonoscopy. TaqMan probe assay was performed for C677T MTHFR polymorphism. Sera were fractionated from the blood samples of 43 patients and controls and folate and Vit B₁₂ concentrations were measured by a monobind kit. The correlation of MTHFR polymorphisms and folate/vitamin-B₁₂ with CRC risk was analyzed.

Results

In the current study, we found the frequency of three different genotypes of MTHFR polymorphism in the Iranian population i.e., CC, CT, and TT, to be 51.31, 26.73, 21.96 and 61, 32.2, 6.8 in case and control groups, respectively. The homozygote genotype of MTHFR rs1801133 polymorphism is associated with an increased risk of CRC by 3.68, 1.42, and 3.74-fold in codominant, dominant, and recessive models respectively (p value < 0.01). Our study revealed that there was no significant difference between the amount of folate and Vit B12 in the case and control groups (p value > 0.05).

Conclusions

This study revealed that there was no significant difference between the amount of folate and Vit B₁₂ in the case and control groups. Furthermore, our results demonstrated a higher risk association for 677TT and 677TT + C677T genotypes of MTHFR compared with 677CC carriers among CRC patients.

The methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism is associated with breast cancer subtype susceptibility in southwestern China

Methylenetetrahydrofolate reductase (MTHFR), a folate-dependent enzyme, is reportedly involved in several cancer types. The MTHFR C677T polymorphism influences many biological processes, including tumorigenesis. However, the association between the MTHFR C677T polymorphism and breast cancer (BC) subtypes is not fully understood. In this study, the MTHFR C677T polymorphism was genotyped in 490 individuals with or without BC from southwestern China. Analysis of the association between the MTHFR C677T polymorphism and BC revealed that there was a significant association between the MTHFR C677T polymorphism and triple-negative breast cancer (TNBC) (OR = 2.83, 95% CI: 1.12-9.51, P = 0.0401). Furthermore, the MTHFR C677T polymorphism can also serve as a protective factor in luminal A breast cancer (OR = 0.57, 95% CI: 0.34-0.94, P = 0.0258). Evaluation of the association between the MTHFR C677T polymorphism and clinical characteristics indicated that people who suffered from hypertension had an increased risk for BC (OR = 2.27; 95% CI: 1.08-4.6; P = 0.0264), especially TNBC (OR = 215.38; 95% CI: 2.45-84430.3; P = 0.0317). Our results suggest that the MTHFR C677T polymorphism is significantly associated with susceptibility to luminal B breast cancer and TNBC.

Epigenetic Mechanisms in DNA Double Strand Break Repair: A Clinical Review

Upon the induction of DNA damage, the chromatin structure unwinds to allow access to enzymes to catalyse the repair. The regulation of the winding and unwinding of chromatin occurs via epigenetic modifications, which can alter gene expression without changing the DNA sequence. Epigenetic mechanisms such as histone acetylation and DNA methylation are known to be reversible and have been indicated to play different roles in the repair of DNA. More importantly, the inhibition of such mechanisms has been reported to play a role in the repair of double strand breaks, the most detrimental type of DNA damage. This occurs by manipulating the chromatin structure and the expression of essential proteins that are critical for homologous recombination and non-homologous end joining repair pathways. Inhibitors of histone deacetylases and DNA methyltransferases have demonstrated efficacy in the clinic and represent a promising approach for cancer therapy. The aims of this review are to summarise the role of histone deacetylase and DNA methyltransferase inhibitors involved in DNA double strand break repair and explore their current and future independent use in combination with other DNA repair inhibitors or pre-existing therapies in the clinic.

The Concept of Folic Acid in Health and Disease

Folates have a pterine core structure and high metabolic activity due to their ability to accept electrons and react with O-, S-, N-, C-bounds. Folates play a role as cofactors in essential one-carbon pathways donating methyl-groups to choline phospholipids, creatine, epinephrine, DNA. Compounds similar to folates are ubiquitous and have been found in different animals, plants, and microorganisms. Folates enter the body from the diet and are also synthesized by intestinal bacteria with consequent adsorption from the colon. Three types of folate and antifolate cellular transporters have been found, differing in tissue localization, substrate affinity, type of transferring, and optimal pH for function. Laboratory criteria of folate deficiency are accepted by WHO. Severe folate deficiencies, manifesting in early life, are seen in hereditary folate malabsorption and cerebral folate deficiency. Acquired folate deficiency is quite common and is associated with poor diet and malabsorption, alcohol consumption, obesity, and kidney failure. Given the observational data that folates have a protective effect against neural tube defects, ischemic events, and cancer, food folic acid fortification was introduced in many countries. However, high physiological folate concentrations and folate overload may increase the risk of impaired brain development in embryogenesis and possess a growth advantage for precancerous altered cells.

Metabolic pathways in sporadic colorectal carcinogenesis: A new proposal

Given the reports made about geographical differences in Colorectal Cancer (CRC) occurrence, suggesting a link between dietary habits, genes and cancer risk, we hypothesise that there are four fundamental metabolic pathways involved in diet-genes interactions, directly implicated in colorectal carcinogenesis: folate metabolism; lipid metabolism; oxidative stress response; and inflammatory response. Supporting this hypothesis are the evidence given by the significant associations between several diet-genes polymorphisms and CRC, namely: MTHFR, MTR, MTRR and TS (involved in folate metabolism); NPY, APOA1, APOB, APOC3, APOE, CETP, LPL and PON1 (involved in lipid metabolism); MNSOD, SOD3, CAT, GSTP1, GSTT1 and GSTM1 (involved in oxidative stress response); and IL-1, IL-6, TNF-α, and TGF-β (involved in inflammatory response). We also highlight the association between some foods/nutrients/nutraceuticals that are important in CRC prevention or treatment and the four metabolic pathways proposed, and the recent results of genome-wide association studies, both assisting our hypothesis. Finally, we propose a new line of investigation with larger studies, using accurate dietary biomarkers and investigating the four metabolic pathways genes simultaneously. This line of investigation will be essential to understand the full complexity of the association between nature and nurture in CRC and perhaps in other types of cancers. Only with this in-depth knowledge will it be possible to make personalised nutrition recommendations for disease prevention and management.

Genetic variants in the Folic acid Metabolic Pathway Genes predict outcomes of metastatic Colorectal Cancer patients receiving first-line Chemotherapy

Background: The association between genetic variants in the folic acid metabolic pathway genes and survival, as well as the responses to chemotherapy of metastatic colorectal cancer (mCRC) patients has not been reported. Methods: The association between genetic variants in the folic acid metabolic pathway genes and progression-free survival (PFS) and overall survival (OS) of mCRC patients were analyzed using Cox regression model. The false discovery rate (FDR) correction method was conducted. The logistic regression model was used to explore the effects of the interested genetic variants on disease control rate (DCR). The Cancer Genome Atlas (TCGA) database was applied to compare gene expression differences. Results: We found that rs3786362 G allele of thymidylate synthase (TYMS) gene was significantly associated with PFS (P = 1.10 × 10^-2), OS (P = 2.50 × 10^-2) and DCR (P = 5.00 × 10^-3). The expression of TYMS was overexpressed in CRC tissues compared with adjacent normal tissues. Furthermore, TYMS expression level decreased with respect to younger age and advanced tumor stage. Conclusion: Genetic variants in the folic acid metabolic pathway genes might serve as potential prognostic biomarkers for mCRC patients.

How Dietary Factors Affect DNA Methylation: Lesson from Epidemiological Studies

Over the past decades, DNA methylation has been proposed as a molecular mechanism underlying the positive or negative effects of diet on human health. Despite the number of studies on this topic is rapidly increasing, the relationship between dietary factors, changes in DNA methylation and health outcomes remains unclear. In this review, we summarize the literature from observational studies (cross-sectional, retrospective, or prospective) which examined the association of dietary factors (nutrients, foods, and dietary patterns) with DNA methylation markers among diseased or healthy people during the lifetime. Next, we discuss the methodological pitfalls by examining strengths and limitations of published studies. Finally, we close with a discussion on future challenges of this field of research, raising the need for large-size prospective studies evaluating the association between diet and DNA methylation in health and diseases for appropriate public health strategies.

High expression of TCN1 is a negative prognostic biomarker and can predict neoadjuvant chemosensitivity of colon cancer

Transcobalamin (TCN1) is a vitamin B12 (cobalamin)-binding protein that regulates cobalamin homeostasis. Recent studies and bioinformatic analyses have found that TCN1 is highly expressed in cancer tissues and is associated with tumour aggressiveness and poor prognosis. The present study aimed to detect TCN1 as a novel biomarker for prognosis and chemosensitivity of colon cancer. Next-generation sequencing showed that TCN1 was one of several upregulated mRNAs in colon cancer, which was verified by further bioinformatics analyses. Western blotting (n = 9) and quantitative real time polymerase chain reaction (qRT-PCR, n = 30) revealed that TCN1 was highly expressed in colon cancer tissues at both the protein and mRNA level. A total of 194 cases of colon cancer were examined by immunohistochemistry and revealed that TCN1 expression level was related to advanced stages (P < 0.005). Kaplan-Meier analysis verified that patients with lower TCN1 expression usually had longer overall survival (P = 0.008). In addition, TCN1 was highly expressed in pulmonary metastatic tumour tissues (n = 37, P = 0.025) and exhibited higher levels in right-sided colon cancer than in left-sided colon cancer (P = 0.029). TCN1 expression in specimens that had received neoadjuvant chemotherapy decreased compared with that in colonoscopy biopsy tissues (n = 42, P = 0.009). Further bioinformatics analyses verified that apoptosis pathways might have a role in high TCN1 expression. All the studies revealed that TCN1 expression in colon cancer was significantly associated with malignant biological behaviour. Therefore, TCN1 could be used as a novel biomarker for colon cancer aggressiveness and prognosis and might also be a potential biomarker for predicting neoadjuvant chemosensitivity.

Cysteine as a Carbon Source, a Hot Spot in Cancer Cells Survival

Cancer cells undergo a metabolic rewiring in order to fulfill the energy and biomass requirements. Cysteine is a pivotal organic compound that contributes for cancer metabolic remodeling at three different levels: (1) in redox control, free or as a component of glutathione; (2) in ATP production, via hydrogen sulfide (H₂S) production, serving as a donor to electron transport chain (ETC), and (3) as a carbon source for biomass and energy production. In the present review, emphasis will be given to the role of cysteine as a carbon source, focusing on the metabolic reliance on cysteine, benefiting the metabolic fitness and survival of cancer cells. Therefore, the interplay between cysteine metabolism and other metabolic pathways, as well as the regulation of cysteine metabolism related enzymes and transporters, will be also addressed. Finally, the usefulness of cysteine metabolic route as a target in cancer treatment will be highlighted.