Identification and verification of the role of crucial genes through which methionine restriction inhibits the progression of colon cancer cells

Ultra-High Dose Oral ω3 Eicosapentaenoic Acid (EPA), Docosahexaenoic Acid (DHA), or Oxidation-Resistant Deuterated DHA Block Tumorigenesis in a MYCN-Driven Neuroblastoma Model

Background/Objectives: Neuroblastoma is a genetically diverse, highly metastatic pediatric cancer accounting for 15% of childhood cancer deaths despite only having ~8% of childhood cancer incidence. The current standard of care for high-risk diseases is highly genotoxic. This, combined with less than 50% survival in high-risk diseases and an abysmal 5% survival in relapsed cases, makes discovering novel, effective, and less toxic treatments essential. Methods: A prophylactic syngeneic mouse model was used to test high-dose lipid-mediator highly unsaturated fatty acids on tumorigenesis. Wildtype mice were gavaged with 12.3-14.6 g/d (adult human equivalent) omega-3 EPA, DHA, or oxidation-resistant bis allylic deuterated DHA (D-DHA) and 4.6-6.0 g/d arachidonic acid (ARA). At seven days, MYCN-expressing murine neuro-2a cells syngeneic to the gavaged mice were injected subcutaneously. Oral gavage continued for 10-20 d post-injection when tumors and tissues were harvested. Results: Fifty percent of control (not gavaged) animals form tumors (4/8) at about 10 d. High-dose DHA, D-DHA, and EPA block tumor formation completely in n = 8 or 10 animals. In contrast, ω6 arachidonic acid (4.6-6.0 g/d) enhances tumor formation (6/10 tumors) and reduces latency (5.5 to 10 days) compared to the control. The co-delivery of ARA and EPA results in a reduced tumor burden analogous to the control group, suggesting that EPA directly opposes the mechanism of ARA-mediated tumor formation. DHA acts through a non-oxidative mechanism. Conclusions: Sustained high-dose ω3 (weeks/months) is safe and well-tolerated in humans. These results suggest that ω3 DHA and EPA delivery at ultra-high doses may represent a viable low-toxicity therapy for neuroblastoma.

Role of amino acid metabolism in tumor immune microenvironment of colorectal cancer

This review investigates the role of amino acid metabolism in the tumor microenvironment of colorectal cancer (CRC) and explores potential targeted therapeutic strategies. The paper synthesized current research on amino acid metabolism in the colorectal cancer tumor microenvironment, focusing on amino acids such as tryptophan, methionine, glutamine, and arginine. It examined their impact on tumor growth, immune evasion, and patient prognosis, as well as the metabolic reprogramming of tumor cells and complex tumor microenvironment interactions. Aberrant amino acid metabolism was a hallmark of colorectal cancer, influencing tumor proliferation, survival, and invasiveness. Key findings included: Tryptophan metabolism via the kynurenine and serotonin pathways significantly affected immune response and tumor progression in CRC. Methionine influenced T cell function and DNA methylation, playing a critical role in tumor development. Glutamine was extensively used by tumor cells for energy metabolism and supported immune cell function. Arginine metabolism impacted CD8+ T cell functionality and tumor growth. The review also discussed the dual roles of immune cells in the tumor microenvironment and the potential of targeting amino acid metabolic pathways for CRC treatment. In conclusion, amino acid metabolism significantly impacts the colorectal cancer tumor microenvironment and immunity. Understanding these metabolic pathways provides valuable insights into CRC pathogenesis and identifies potential therapeutic targets. Future research should focus on developing treatments that disrupt these metabolic processes to improve patient outcomes in CRC.

Targeting CHEK1: Ginsenosides-Rh2 and Cu2O@G-Rh2 nanoparticles in thyroid cancer

Thyroid cancer (THCA) is an increasingly common malignant tumor of the endocrine system, with its incidence rising steadily in recent years. For patients who experience recurrence or metastasis, treatment options are relatively limited, and the prognosis is poor. Therefore, exploring new therapeutic strategies has become particularly urgent. This study confirmed that effective suppression of THCA cell proliferation and stimulation of apoptosis can be achieved through the application of Ginsenosides-Rh2. Through network pharmacology screening, the molecular target of Ginsenosides-Rh2 in THCA was identified as CHEK1, and its inhibitory effect was confirmed by downregulating CHEK1 protein expression. Furthermore, demonstrations conducted both in vitro and in vivo showcased that delivering Ginsenosides-Rh2 using nanoparticle carriers significantly reduced cell viability by approximately 50%, regulated DNA damage levels, apoptosis-related protein expression, and cell cycle control. The IC50 of the nanoparticle formulation was determined (B-CPAP IC50 = 88.24 μM), TPC IC50 = 79.52 μM). This study confirmed that Cu2O@G-Rh2 is effective in suppressing tumors and exhibits a significant inhibitory effect on tumor recurrence and metastasis while maintaining good safety. Cu2O@G-Rh2 nanoparticles possess excellent stability and anti-tumor efficacy. This research offers new perspectives for the treatment of THCA and demonstrates potential clinical applications.

Targeting CSF1R in myeloid-derived suppressor cells: insights into its immunomodulatory functions in colorectal cancer and therapeutic implications

OBJECTIVE

This study aimed to investigate the critical role of MDSCs in CRC immune suppression, focusing on the CSF1R and JAK/STAT3 signaling axis. Additionally, it assessed the therapeutic efficacy of LNCs@CSF1R siRNA and anti-PD-1 in combination.

METHODS

Single-cell transcriptome sequencing data from CRC and adjacent normal tissues identified MDSC-related differentially expressed genes. RNA-seq analysis comprehensively profiled MDSC gene expression in murine CRC tumors. LNCs@CSF1R siRNA nanocarriers effectively targeted and inhibited CSF1R. Flow cytometry quantified changes in MDSC surface markers post-CSF1R inhibition. RNA-seq and pathway enrichment analyses revealed the impact of CSF1R on MDSC metabolism and signaling. The effect of CSF1R inhibition on the JAK/STAT3 signaling axis was validated using Colivelin and metabolic assessments. Glucose and fatty acid uptake were measured via fluorescence-based flow cytometry. The efficacy of LNCs@CSF1R siRNA and anti-PD-1, alone and in combination, was evaluated in a murine CRC model with extensive tumor section analyses.

RESULTS

CSF1R played a significant role in MDSC-mediated immune suppression. LNCs@CSF1R siRNA nanocarriers effectively targeted MDSCs and inhibited CSF1R. CSF1R regulated MDSC fatty acid metabolism and immune suppression through the JAK/STAT3 signaling axis. Inhibition of CSF1R reduced STAT3 activation and target gene expression, which was rescued by Colivelin. Combined treatment with LNCs@CSF1R siRNA and anti-PD-1 significantly slowed tumor growth and reduced MDSC abundance within CRC tumors.

CONCLUSION

CSF1R via the JAK/STAT3 axis critically regulates MDSCs, particularly in fatty acid metabolism and immune suppression. Combined therapy with LNCs@CSF1R siRNA and anti-PD-1 enhances therapeutic efficacy in a murine CRC model, providing a strong foundation for future clinical applications.

Does Methionine Status Influence the Outcome of Selenomethinione Supplementation? A Comparative Study of Metabolic and Selenium Levels in HepG2 Cells

Methionine restriction and selenium supplementation are recommended because of their health benefits. As a major nutrient form in selenium supplementation, selenomethionine shares a similar biological process to its analog methionine. However, the outcome of selenomethionine supplementation under different methionine statuses and the interplay between these two nutrients remain unclear. Therefore, this study explored the metabolic effects and selenium utilization in HepG2 cells supplemented with selenomethionine under deprived, adequate, and abundant methionine supply conditions by using nuclear magnetic resonance-based metabolomic and molecular biological approaches. Results revealed that selenomethionine promoted the proliferation of HepG2 cells, the transcription of selenoproteins, and the production of most amino acids while decreasing the levels of creatine, aspartate, and nucleoside diphosphate sugar regardless of methionine supply. Selenomethionine substantially disturbed the tricarboxylic acid cycle and choline metabolism in cells under a methionine shortage. With increasing methionine supply, the metabolic disturbance was alleviated, except for changes in lactate, glycine, citrate, and hypoxanthine. The markable selenium accumulation and choline decrease in the cells under methionine shortage imply the potential risk of selenomethionine supplementation. This work revealed the biological effects of selenomethionine under different methionine supply conditions. This study may serve as a guide for controlling methionine and selenomethionine levels in dietary intake.