Abstract
Background
The long-term biological effects of low-level exposure to artificial sweeteners remain debated. We integrated computational toxicology and Mendelian randomization (MR) to explore potential biological responses associated with sodium saccharin across multiple cancer outcomes.
Methods
Public databases were screened to identify saccharin-related targets, followed by protein–protein interaction network construction and enrichment analyses. Molecular docking assessed binding potential. Two-sample MR analyses were conducted using European genome-wide association study (GWAS) summary statistics to evaluate potential causal associations.
Results
Among 191 identified targets, 160 overlapped with genes implicated across 36 cancer types. Hub genes included TP53, IL6, and MAPK3, with docking indicating moderate binding affinity. Enrichment analyses highlighted inflammatory pathways including interleukin-17 signaling. MR analyses suggested inverse associations with non-melanoma skin cancer (odds ratio [OR] = 0.38, P = 0.006) and colon cancer (OR = 0.56, P < 0.001), while a preliminary positive signal was observed for Kaposi sarcoma (OR = 3.73, P = 0.044). No significant associations were detected for most other cancers.
Conclusion
Sodium saccharin may interact with cancer-related molecular networks; however, population-level evidence indicates heterogeneous and context-dependent associations rather than a generalized carcinogenic effect under low-level exposure conditions.
Keywords
1. Introduction
Cancer remains a leading cause of mortality worldwide, with an estimated 20 million new cases and 9.7 million deaths reported in 2022. 1 Artificial sweeteners are widely used globally as food additives, and their long-term health effects remain a controversial topic in public health. Since its discovery in the late 19th century, saccharin has been added to beverages, processed foods, and table sweeteners due to its high sweetness and zero-calorie profile. 2 Pharmacokinetic studies indicate that saccharin is not metabolized in humans and is excreted unchanged via the kidneys. 3 Although major regulatory agencies, including the Food and Drug Administration and European Food Safety Authority, consider saccharin safe within established intake limits, these assessments do not rule out potential biological activity. Historically, saccharin faced scrutiny regarding carcinogenicity based on animal studies. A recent comprehensive review of animal and mechanistic evidence reaffirmed that high-quality studies have not shown genotoxic or carcinogenic potential for non-sugar sweeteners, noting that saccharin-induced bladder tumors in rats occur via mechanisms irrelevant to human physiology.4-6 However, most existing epidemiological evidence comes from observational studies, which are susceptible to residual confounding or exposure measurement errors. Mechanistic simulation and causal inference are therefore necessary to clarify the relationship between saccharin exposure and human cancer risk.
Potential health risks of saccharin may arise from interference with cellular signaling networks. Sodium saccharin can activate taste receptors in the ovaries of rats with polycystic ovary syndrome. This activation enhances p38-MAPK/ERK signaling, accompanied by changes in apoptosis markers and the disruption of steroidogenesis. Cellular experiments further demonstrated that saccharin promotes neutrophil chemotaxis and migration via TAS1R2/TAS1R3 sweet taste receptors, upregulating inflammatory chemokines such as CXCL1 and CCL2. 7 Microbiological studies revealed that saccharin can destabilize bacterial cell membranes and interfere with DNA replication kinetics, suggesting a molecular potential to disrupt basic biological processes. 8 Furthermore, in vitro and in vivo experiments confirmed that sodium saccharin activates the T1R3 taste receptor, regulating downstream transcription factors via the cAMP-PKA pathway and affecting testosterone synthesis. 9 Current research relies heavily on in vitro and animal models, making direct extrapolation to complex human systems difficult. Computational toxicology can systematically simulate molecular interference networks to predict potential risks, while Mendelian randomization (MR) assesses causal associations with health outcomes based on human genetic variation, addressing the limitations of traditional experimental evidence regarding extrapolation and causal inference.
Most current studies assessing saccharin risks are limited to single experimental methods or focus on individual cancer types. This approach lacks a system-level perspective that integrates molecular mechanisms with population evidence. Traditional toxicological assessments focus primarily on acute toxicity or clear carcinogenicity at high doses, often overlooking complex effects triggered by long-term low-dose exposure. In this study, “low-level exposure” is operationally defined as chronic dietary intake of sodium saccharin within the acceptable daily intake range (≤9 mg/kg body weight/day) established by the European Food Safety Authority (EFSA). 10 This intake-based definition reflects real-world exposure conditions under habitual consumption and distinguishes physiological exposure from high-dose experimental toxicity settings. The corresponding internal levels measured by metabolomic GWAS are therefore interpreted as proxies of this exposure state. Such effects typically perturb cellular homeostasis through multiple targets and pathways, defined as network toxicity. 11 Additionally, it remains unclear whether the association between saccharin and different cancers is specific. Whether the risk presents as a pan-cancer characteristic or varies by cancer type is a critical scientific question. Computational toxicology systematically predicts biological targets and signaling pathways that chemicals may interfere with, simulating mechanisms of multi-target mediated network toxicity. MR uses genetic variants as instrumental variables (IVs) to assess causal relationships between environmental exposures and disease outcomes, largely minimizing confounding bias inherent in observational studies. 12 Integrating these methods helps construct an integrated evidence chain from molecular hypothesis to population-level causal inference, enabling a systematic assessment of the long-term health risks of saccharin.
A multi-level analysis framework integrating computational toxicology and genetic epidemiology was constructed to assess the potential carcinogenic risk of sodium saccharin and clarify heterogeneous association patterns. By establishing a saccharin-target-cancer interaction network, conducting molecular docking validation, and performing two-sample MR analysis, this study aimed to: (1) systematically predict cancer-related targets and signaling pathways potentially disrupted by saccharin; (2) evaluate binding possibilities with key targets structurally; and (3) explore potential causal associations between saccharin and 36 cancer types from a population genetics perspective.
2. Methods
2.1. Sodium Saccharin Target Collection
The data acquisition, computational simulations, and statistical analyses for this study were systematically conducted from September 2025 to January 2026. The overall workflow of this study, integrating network toxicology, molecular docking, and Mendelian randomization, is illustrated in Figure 1. The standard 2D structural formula of sodium saccharin (Molecular Formula: C7H5NO3S) was obtained from the PubChem database.
13
Targets related to sodium saccharin were searched using the isomeric SMILES in the SwissTargetPrediction
14
and SEA
15
databases. Searches were also conducted in the Comparative Toxicogenomics Database (CTD),
16
STITCH,
17
Super-PRED,
18
GeneCards,
19
and Therapeutic Target Database
20
using “Saccharin” as the keyword. The species was limited to Homo sapiens. In SwissTargetPrediction, a Probability > 0.01 was used as the selection criterion. Targets obtained from different databases were merged for subsequent analysis. Flowchart of the study design. Flowchart of the integrated computational toxicology and mendelian randomization study design
2.2. Cancer-Related Target Collection
Information on the 36 Cancer Types Included in the Study
Note. Information on the 36 cancer types analyzed in this study. Cancers were systematically categorized into 10 anatomical systems to facilitate downstream specific target intersection analysis.
2.3. Identification of Saccharin-Cancer Common Targets
A Venn diagram was generated using an online bioinformatics platform to identify common target genes. 22 The 36 cancers were classified according to anatomical physiology, and intersections with sodium saccharin targets were determined.
2.4. Construction of the Saccharin-Target-Cancer Network
The intersection targets were used to construct a Saccharin-Target-Cancer interaction network using Cytoscape 3.10.1 software. Topological analysis was performed using the CytoNCA plugin. 23 Nodes were ranked by degree value to screen for key targets. An integrated network containing three levels of nodes was manually constructed: saccharin molecules (compound layer), identified core targets (target layer), and 36 cancer types (disease layer). Edges represented compound-target and target-disease interactions. This network visualized the potential pleiotropic mechanisms by which saccharin affects multiple cancers through multi-target regulation.
2.5. Protein-Protein Interaction (PPI) Network Construction
Saccharin-cancer intersection targets were imported into the STRING database, 24 with the organism set to Homo sapiens and a minimum interaction score threshold of 0.400. Isolated nodes were hidden. Interaction data were imported into Cytoscape (version 3.10.1) for visualization and analysis. The built-in NetworkAnalyzer tool calculated topological parameters, 25 including degree, betweenness centrality, and closeness centrality. To identify hub genes, algorithms such as Maximal Clique Centrality (MCC) in the CytoHubba plugin were used for ranking.
2.6. GO and KEGG Enrichment Analysis
Statistical analysis was performed using R version 4.3.1. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) 26 enrichment analyses were performed on intersection genes using R packages including clusterProfiler, 27 enrichplot, 28 org.Hs.eg.db, 29 and ggplot2. 30 GO analysis covered biological process, cellular component, and molecular function. The significance of KEGG enrichment results was tested using the hypergeometric distribution and corrected for False Discovery Rate. The threshold was set at an adjusted P-value (adj.P.Val) < 0.05. Results were visualized as bar plots, bubble plots, and Sankey diagrams for the top 10 pathways.
2.7. Molecular Docking and Visualization
Molecular docking was employed to predict potential mechanisms. The chemical structure of saccharin was downloaded from PubChem, and target protein structures were obtained from UniProt and the RCSB PDB database. 31 AutoDockTools 1.5.7 was used to process ligand and protein files into PDBQT format. AutoDock Vina performed docking to obtain binding energy data. PyMOL was used to visualize the docking results between proteins and ligands.
2.8. Mendelian Randomization Analysis
Two-sample MR was employed to investigate the potential causal association between saccharin exposure and the risk of multiple cancers.
2.8.1. Instrumental Variable Selection
Instrumental variables for saccharin exposure were obtained from a large-scale genome-wide association study on human blood metabolites in a European population (N = 7,824; quantified via untargeted mass spectrometry-based metabolomics). 32 Given that saccharin is minimally metabolized and predominantly excreted unchanged in urine, circulating metabolite levels can serve as a proxy for internal exposure. However, the genetic variants derived from metabolomic GWAS primarily capture inter-individual differences in absorption, distribution, and excretion processes, rather than direct dietary intake volumes. Therefore, they are utilized as genetic proxies for chronic internal exposure to saccharin, rather than exact measures of absolute dietary consumption. Selection strictly followed core MR assumptions 33 : (1) Relevance: Single Nucleotide Polymorphisms (SNPs) significantly associated with blood/urine saccharin levels at the genome-wide level (P < 5 × 10-6) were selected; (2) Independence: SNPs were clumped using the 1000 Genomes Project European reference panel with linkage disequilibrium r2 < 0.001 and a window of > 10,000 kb to ensure independence; (3) Exclusion of weak IVs: The F-statistic for each SNP was calculated, with F > 10 indicating sufficient strength.
2.8.2. Data Sources
Outcome data (incidence risk of 36 cancers) were derived from independent, large-sample GWAS summary statistics. To maintain consistency and feasibility, oropharyngeal and hypopharyngeal cancers were grouped as “pharyngeal cancer” based on anatomical proximity. Nasopharyngeal, vaginal, and penile cancers were excluded due to the lack of publicly available GWAS data meeting IV selection requirements and statistical power. All included outcome data were based on populations of European ancestry to minimize bias from population stratification.
2.8.3. Statistical Analysis
Inverse Variance Weighted (IVW) meta-analysis was used as the primary method for estimating causal effects. Sensitivity analyses were performed to ensure robustness: (1) MR-Egger regression to assess and correct for pleiotropy, determining directional pleiotropy via the intercept term (P < 0.05) 34 ; (2) Weighted Median method, which provides unbiased estimates even if up to 50% of IVs are invalid 35 ; (3) MR-PRESSO to detect and remove outlier SNPs. 36 Heterogeneity among IVs was assessed using Cochran’s Q statistic. 37 All analyses were implemented using the TwoSampleMR package (version 0.5.8) in R software (version 4.3.1), with P < 0.05 considered statistically significant.
3. Results
3.1. Screening and Identification of Potential Saccharin Targets
Predicted and known interaction data from seven databases were integrated. Analysis was limited to Homo sapiens. Starting with the 2D structure (Figure 2A) and molecular details (Table 2) of sodium saccharin from PubChem, the isomeric SMILES string was used to search SwissTargetPrediction with a probability threshold > 0.01. The SEA method predicted targets based on chemical similarity. Merging and deduplicating results from all databases yielded 191 unique gene targets. Identification of common targets. (A) Standard 2D structural formula of sodium saccharin; (B) Venn diagram showing the intersection of 191 saccharin targets and 21,226 cancer targets Molecular Details of Saccharin (PubChem CID 5143) Note. Detailed information about saccharin molecules.(National Center for Biotechnology Information (2025). PubChem Compound Summary for CID 5143, Saccharin. Retrieved December 22, 2025 from https://pubchem.ncbi.nlm.nih.gov/compound/Saccharin).
3.2. Acquisition of Targets for 36 Cancers
Common Targets Shared Across 36 Cancer Types
Note. List of the 20 common core targets shared across all 36 investigated cancer types. These targets primarily converge on pathways related to cell cycle regulation, apoptosis, and immune-inflammatory responses.
3.3. Identification of Common Disease-Compound Targets
Comparing the 191 saccharin targets with the 21,226 cancer targets using a Venn diagram revealed 160 intersection targets (Figure 2B). This high overlap (approximately 83.8%) suggests that saccharin targets and cancer-related targets are closely linked, implying saccharin may participate in core biological processes related to cancer through these shared targets.
To explore the relationship between saccharin targets and specific cancer types, the 36 cancers were classified into 10 anatomical system groups: head, neck, thoracic organs, digestive system, digestive glands, urinary system, female reproductive system, male reproductive system, hematologic/lymphatic system, and skin/soft tissue tumors. Intersection analysis between the 191 saccharin targets and the target sets of these 10 categories revealed the “saccharin-cancer anatomical classification intersection targets” (Figure 3A–J). The anatomical system-based grouping was designed to characterize the organ-level distribution patterns of saccharin targets. By identifying targets consistently shared across multiple anatomical systems, this approach enables the prioritization of genes with systemic pleiotropic relevance, thereby reducing bias introduced by organ-specific noise and strengthening the robustness of downstream core target identification. Organ distribution characteristics. Venn diagrams of intersection targets across 10 anatomical cancer groups (A-J), providing a logical basis for downstream core target screening
3.4. Construction and Analysis of the Saccharin-Target-Cancer Multidimensional Interaction Network
A three-layer integrated network was constructed to reveal the potential pleiotropic mechanism of saccharin. Network analysis identified multiple core targets with high degree values located at hub positions. The constructed compound-target-disease network (Figure 4) showed that saccharin acts on 144 core targets forming an extensive association network with various cancer types, indicating a mechanism of cross-cancer effects through multi-target synergistic action. Multidimensional saccharin-target-cancer interaction network. The network illustrates the pleiotropic mapping from the compound (saccharin, top right) to 144 core targets (middle layer), and subsequently to the 36 specific cancer types (left layer). Node size and color intensity indicate the topological degree
3.5. PPI Network Construction and Core Hub Target Selection
The PPI network of saccharin-cancer intersection targets (Figure 5A) was constructed to identify key mechanisms. Topological analysis indicated a centralized network structure. Using multiple centrality algorithms, a group of core hub targets was identified, with ALB, IL6, TNF, and MAPK3 exhibiting prominent values for degree and betweenness centrality (Figure 5B). The “Saccharin-Core Target-Cancer” integrated network (Figure 5C) demonstrates that saccharin is widely associated with multiple cancers by regulating a functional module of highly interconnected core targets. Protein-protein interaction (PPI) network analysis. (A) Overall PPI network of intersection targets constructed via string database; (B) Bar chart ranking the top 20 core hub targets based on degree centrality; (C) The highly interconnected “Saccharin-core target-cancer” functional module extracted using CytoHubba, highlighting central nodes such as ALB, IL6, TNF, and MAPK3
3.6. GO and KEGG Functional Enrichment Analysis of Core Targets
Functional enrichment analysis of the 144 core targets using the DAVID database revealed 804 significantly enriched biological processes, 21 cellular component terms, and 38 molecular function terms (Figure 6A). Top terms indicated involvement in cytokine-mediated signaling pathways, regulation of apoptosis, and negative regulation of cell proliferation. Targets were primarily located in the cytoplasm and nucleus, with molecular functions concentrated in enzyme binding, transcription factor binding, and cytokine receptor binding. KEGG pathway analysis identified 150 significantly enriched pathways (Figure 6B), including the interleukin-17 (IL-17) signaling pathway, AGE-RAGE signaling pathway, cAMP signaling pathway, lipid and atherosclerosis pathway, and nitrogen metabolism pathway. These pathways may play a central regulatory role in the process by which saccharin affects cancer. Functional enrichment analysis of core targets. (A) Top Gene Ontology (GO) terms across Biological Process, Cellular Component, and Molecular Function categories; (B) Sankey bubble plot of the significantly enriched KEGG pathways, illustrating the mapping of specific genes to key pathways
3.7. Molecular Docking Validation and Binding Mode Analysis
Molecular docking validated the interaction between saccharin and 13 core protein targets. A bubble heatmap showed binding energies consistently below -5 kcal/mol (Figure 7A). Visualization of selected lower-energy bindings (Figure 7B–F) revealed specific interactions: saccharin formed hydrogen bonds with residues ARG-257, ALA-261, and SER-287 of ALB (-6.6 kcal/mol); ARG-155 of FOS (-7.0 kcal/mol); DA-31, YS-273, and DG-30 of JUN (-6.8 kcal/mol); PRO-315 and ASN-316 of MAPK3 (-6.4 kcal/mol); and MET-154 and LYS-157 of IL10 (-6.4 kcal/mol). The visualization of docking complexes (Figure 7B–F) suggests that saccharin may interact with functionally relevant regions of these targets. For ALB, saccharin is located within a hydrophobic binding pocket and forms hydrogen bonds with ARG-257, ALA-261, and SER-287. For FOS and JUN, saccharin binds near specific residues (e.g., ARG-155, DA-31) involved in transcriptional regulation. For MAPK3, binding occurs in proximity to the catalytic pocket (PRO-315, ASN-316), which may influence kinase activity. Similarly, interaction with IL10 involves residues located in functionally relevant regions (MET-154, LYS-157). These findings provide preliminary structural clues but require future experimental validation. Molecular docking results and visualization. (A) Bubble heatmap of binding energies for core targets; (B-F) Visualization of specific binding sites and hydrogen bond formation for ALB, FOS, IL10, JUN, and MAPK3
3.8. Causal Association Between Saccharin and Cancer via Mendelian Randomization
3.8.1. Instrumental Variables and Outcome Data
GWAS Summary Data Sources for the 32 Cancer Outcomes Analyzed in Mendelian Randomization
Note. Detailed source information for the GWAS summary statistics used in the Mendelian randomization analysis. All datasets were restricted to populations of European ancestry to minimize population stratification bias.
3.8.2. Causal Association Between Saccharin and Cancer Risk
Primary IVW analysis (Figure 8) showed statistically significant associations between genetically predicted higher saccharin levels and risk in three of the 32 cancers. Saccharin showed a protective association with non-melanoma skin cancer (OR = 0.38, 95% CI: 0.19–0.76, P = 0.006) and colon cancer (OR = 0.56, 95% CI: 0.41–0.78, P < 0.001). Conversely, a positive association was observed with Kaposi sarcoma risk (OR = 3.73, 95% CI: 1.04–13.40, P = 0.044). No statistically significant causal associations were found for the remaining 29 cancers, including common types such as brain, breast, lung, and prostate cancer (P > 0.05). Forest plot of Mendelian randomization analysis showing the causal association between genetically predicted sodium saccharin levels and cancer risk. OR: Odds Ratio; CI: Confidence Interval
3.8.3. Sensitivity Analysis
MR-Egger regression detected no significant directional pleiotropy (intercept P > 0.05), with estimate directions consistent with IVW. The Weighted Median method also showed consistent directions and magnitudes. MR-PRESSO did not identify any outlier SNPs. Heterogeneity testing indicated heterogeneity in bladder and gastric cancer analyses (Cochran’s Q P < 0.05); however, associations remained non-significant after correction using a random-effects model. Heterogeneity tests for the three significant findings (Kaposi sarcoma, non-melanoma skin cancer, colon cancer) yielded P > 0.05, supporting the reliability of the estimates.
4. Discussion
Artificial sweeteners are widely used in the global food supply, making their long-term health implications an important issue in toxicology and public health. Sodium saccharin, one of the oldest artificial sweeteners, is considered safe within regulatory frameworks, yet its potential biological effects, particularly regarding cancer risk, remain a subject of scientific debate. This study integrated computational toxicology and genetic epidemiology to systematically explore the multidimensional relationship between sodium saccharin and 36 cancers. Through the construction of a Saccharin-Target-Cancer interaction network, PPI analysis, functional enrichment, molecular docking, and MR analysis, potential molecular targets and pathways were revealed, and causal associations with specific cancers were preliminarily assessed from a genetic perspective.
Integrating data from seven databases, 191 potential saccharin targets were identified. Comparison with 21,226 targets related to 36 cancers revealed 160 intersection targets, an overlap of 83.8%. This high overlap suggests extensive intersection between saccharin targets and key molecules in tumorigenesis. The intersection set included TP53, MYC, EGFR, IL6, and TNF. TP53 is a major tumor suppressor gene mutated or inactivated in over 50% of human cancers. 38 MYC is a key transcription factor regulating cell proliferation and metabolism, with abnormal expression closely linked to tumor progression.39,40 Potential interactions between saccharin and these genes suggest interference with basic biological processes such as cell cycle regulation, apoptotic escape, or immune surveillance. Although this does not directly prove carcinogenicity, the ability of saccharin or its metabolites to bind these key targets may affect their normal function under long-term or high-dose exposure.
Network topology analysis showed that the PPI network of saccharin-cancer intersection targets was highly centralized, with nodes such as ALB, IL6, TNF, and MAPK3 exhibiting prominent centrality. These hub genes are often at the core of signal transduction or regulatory networks, where functional perturbation can propagate and affect multiple downstream physiological processes. Chronic inflammation is a driver of cancer development, promoting tumor progression, immune escape, and therapy resistance via signaling pathways such as NF-κB, JAK-STAT, and MAPK. 41 IL-6 and TNF-α play central roles in the tumor microenvironment. IL-6 is a key driver in breast cancer multi-omics networks and promotes tumor growth via synergy with proteins like CRP. 42 TNF-α activates pathways such as NF-κB in head and neck squamous cell carcinoma, mediating invasion, metastasis, and shaping the immunosuppressive microenvironment. 43 Network analysis also highlighted ALB as a hub gene in clear cell renal cell carcinoma and MAPK3 as significantly associated with immune infiltration in glioma. 44 Targeting inflammatory factors is currently a focus of clinical research for cancer therapy.
Biologically, these targets were significantly enriched in cytokine-mediated signaling pathways, negative regulation of apoptosis, and negative regulation of cell proliferation, suggesting saccharin may participate in regulating the balance between immune response and cell survival. Pathway analysis showed significant enrichment in IL-17, AGE-RAGE, cAMP, lipid and atherosclerosis, and nitrogen metabolism pathways. The IL-17 pathway links inflammation and tumor progression; abnormal activation promotes proliferation and angiogenesis. IL-17/IL-17RA signaling is essential for tumorigenesis in pancreatic epithelial cells, recruiting inhibitory immune cells via CXCL5 and B7-H4 upregulation. 45 Interaction between antigen-presenting cells and tumor antigens can promote IL-10 and IL-17 expression, weakening anti-tumor immunity. 46 The AGE-RAGE pathway involves advanced glycation end productsbinding to RAGE, activating PI3K-Akt, p38 MAPK, and NF-κB pathways to drive chronic inflammation and cancer. 47 Recent research confirmed that advanced glycation end products induce oxidative stress and apoptosis in intestinal cells via the RAGE/MAPK/NF-κB pathway. 48 The co-enrichment of these pathways suggests the influence of saccharin is not limited to single molecular events but may involve interference with multiple interconnected signaling networks, indirectly shaping a microenvironment favorable for tumorigenesis.
It is worth noting that the enrichment of cAMP signaling and nitrogen metabolism pathways may reflect potential effects of saccharin on cellular energy metabolism and nitrogen balance. Tumor cells often exhibit the Warburg effect, and cAMP regulates cell proliferation via PKA/CREB pathways. Nitrogen metabolism is tightly linked to amino acid utilization and nucleotide synthesis. 49 An integrative analysis found that saccharin targets were significantly enriched in Pathways in cancer, PI3K-Akt signaling, and chemical carcinogenesis-receptor activation. 50 Although direct evidence of saccharin-induced metabolic reprogramming in humans is lacking, potential effects under long-term low-dose exposure warrant further investigation.
Molecular docking validated the interaction between saccharin and 13 core protein targets. Saccharin showed potential binding affinity (energy < -5 kcal/mol) with ALB, FOS, JUN, MAPK3, and IL10. 51 Binding to serum albumin (ALB, -6.6 kcal/mol) via hydrogen bonds suggests specific transport characteristics, as small molecule-albumin interactions determine pharmacokinetics. Furthermore, such systemic transport may alter the pharmacokinetic properties of other endogenous or exogenous compounds. 52 Glycation can alter the HSA binding pocket. 53 Binding near regulatory regions of FOS and JUN raises the possibility of modulating the AP-1 transcriptional complex, which is heavily involved in cellular proliferation, migration, and invasion. 54 Interaction with MAPK3 (ERK1), a core kinase in the MAPK/ERK pathway, involved residues PRO-315 and ASN-316 near the active pocket, potentially affecting kinase conformation or substrate binding. Previous studies also found saccharin binds stably to MAPK3 (molecular docking < -5.0 kcal/mol; SPR KD = 45.0 μM) and may activate pro-inflammatory pathways. 55 Furthermore, association with IL10 may indicate potential involvement in immunological homeostasis and inflammation modulation. 56 However, outside of previously validated targets, these interpretations remain structural hypotheses and should be considered strictly as hypothesis-generating rather than evidence of direct functional effects, warranting rigorous in vivo and in vitro validation in future studies.
Two-sample MR analysis revealed that genetically predicted higher saccharin levels were significantly associated with three cancers: negatively with non-melanoma skin cancer and colon cancer, and positively with Kaposi sarcoma. No significant causal association was found for the other 29 cancers. These results indicate that potential effects are highly heterogeneous across cancer types rather than pan-carcinogenic. Our findings of considerable heterogeneity across cancer types are consistent with emerging evidence. For instance, a recent integrative analysis by Xie et al suggested that artificial sweeteners might increase the risk of kidney, breast, and prostate cancers through multiple signaling pathways. 2 In contrast, our genetic causality assessment did not support significant associations for these specific cancers. Furthermore, the vehicle of consumption appears critical. Pan et al reported no genetic causal association between overall artificial sweetener consumption and most major cancers. 57 Notably, however, their stratified analyses revealed that artificial sweeteners added to coffee were associated with ovarian cancer risks, while those in tea were linked to oral and pharyngeal cancers. 57 Similarly, Zhang et al identified a specific positive association between artificial sweeteners in cereal and respiratory system cancers, whereas perceived aspartame intensity showed a protective effect. 12 The positive association with Kaposi sarcoma (OR = 3.73) in this study, though with a wide confidence interval and marginal significance (P = 0.044), along with protective associations for skin and colon cancers, highlights that health effects may depend heavily on cancer type and exposure context. The positive association with Kaposi sarcoma warrants cautious interpretation. Since Kaposi sarcoma is causally linked to Human Herpesvirus 8 infection, this association might reflect a potential influence of saccharin on immune surveillance pathways, such as the identified IL-6 and TNF signaling, rather than a direct carcinogenic effect. Furthermore, given the limited sample size for this rare cancer type, the possibility of pleiotropic bias cannot be excluded. The protective association observed in colon cancer contrasts with concerns regarding artificial sweeteners and gut microbiota dysbiosis. However, these results rely on genetic predisposition, reflecting lifelong exposure patterns rather than acute intake. Mechanistically, our network analysis indicated interactions between saccharin and inflammatory mediators, including NF-κB and cytokines, which may contribute to an anti-inflammatory microenvironment that counteracts tumorigenesis.
This study constructed a multi-level framework combining network toxicology, molecular docking, and MR. This integration validated the link between molecular mechanism prediction and population causal inference, addressing limitations of traditional toxicology such as high cost and difficulty in establishing causality.
Limitations exist. Network toxicology relies on database predictions, carrying the potential for false positives or negatives. Molecular docking is a static simulation and cannot reflect dynamic processes or concentration-dependence. 58 MR results suggest causal direction but cannot replace prospective studies. 59 Furthermore, specifically regarding the MR analysis, a key limitation of this study lies in the nature of the instrumental variables. As saccharin is an exogenous compound, its circulating levels are influenced by multiple factors, including dietary intake, gut microbiota interactions, and renal excretion. The selected SNPs from the metabolomic GWAS therefore represent metabolite quantitative trait loci (mQTLs), which primarily capture genetic variation in internal handling processes rather than direct intake levels. Consequently, these instruments reflect the biological processing and net internal exposure of saccharin rather than exposure per se. Although this limits interpretability in terms of absolute dietary consumption, it remains highly informative for assessing the potential biological consequences of long-term internal exposure. Finally, alongside the inherent limitations of potential pleiotropy and restriction to European populations, broader exposure contexts must also be evaluated. Dose-response relationships in real-world exposure, interactions with other additives, or individual susceptibility differences were not considered. While saccharin is permitted and likely low-risk at normal dietary levels, potential bioactivity, especially for individuals with chronic inflammation or metabolic abnormalities, warrants exploration. Crucially, these findings should be interpreted within the context of established dietary exposure limits, distinct from high-dose toxicity models.
5. Future Directions and Clinical Relevance
Future research should experimentally validate core targets like MAPK3, IL6, and ALB; use animal models or organoids to assess effects on inflammation and metabolism under realistic exposure; and conduct prospective cohort studies combined with biomarkers to clarify long-term effects.
6. Conclusion
In conclusion, our integrated computational and MR study reveals that low-level, physiological sodium saccharin exposure does not causally increase pan-cancer risk across the general population. Instead, its novel biological impact lies in its subtle interaction with specific immune and metabolic targets (such as ALB, FOS, and IL10). These findings shift the paradigm from broad carcinogenic concerns to targeted immunomodulatory surveillance, providing a robust evidence base for modern food safety re-evaluations.
Footnotes
Acknowledgements
We thank the original authors and consortia for sharing the GWAS summary datasets used in this study.
Ethical Considerations
Not applicable. This study utilizes publicly available aggregate data and does not involve any new animal or human experiments performed by the authors.
Author Contributions
All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by the authors. All authors read and approved the final manuscript.
Funding
This work was supported by the National Natural Science Foundation of China (Grant No. U1804181 to Yanchun Wang); the Collaborative Research Project of Chinese and Western Medicine for Chronic Disease Management (Grant No. CXZH2024029 to Yanchun Wang); the Special Scientific Research Project of Traditional Chinese Medicine of Henan Province (Grant No. 2024ZY2134 to Yanchun Wang); the Top Talent Program of Traditional Chinese Medicine of Henan Provincial Health Commission (Grant No. Yu Wei Zhong Yi Ke Ke Ji [2025] 14 to Yanchun Wang); the Postgraduate Scientific Research Innovation Ability Enhancement Plan Project of Henan University of Chinese Medicine in 2024 (Grant No. 2024KYCX018 to Xin Zhao); and the Science and Technology Key Project of Henan Province (Grant No. 242102311284 to Xuemei Wang).
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Data Availability Statement
The datasets presented in this study can be found in online repositories. The names of the repositories and accession numbers can be found in the article. Publicly available GWAS summary statistics were obtained from the GWAS Catalog (https://www.ebi.ac.uk/gwas/) and saccharin structure data from PubChem (
).
