Mucosal microbial microenvironment in early gastric neoplasia and non-neoplastic gastric disease

Leveraging existing 16S rRNA microbial data to identify diagnostic biomarker in Chinese patients with gastric cancer: a systematic meta-analysis

IMPORTANCE

Gastric cancer is a significant and growing health problem in China. Studies have revealed significant differences in gastric microbiota between patients with gastric cancer and non-cancerous patients, suggesting that microbiota may play a role in tumorigenesis. In this meta-analysis, existing 16S rRNA microbial data were analyzed to find combinations consisting of five genera, which had good efficacy in distinguishing gastric cancer from non-cancerous patients in multiple types of samples. These results lend support to the use of microbial markers in detecting gastric cancer. Moreover, these biomarkers are plausible candidates for further mechanistic research into the role of the microbiota in tumorigenesis.

Alteration of gut microbiome and correlated amino acid metabolism are associated with acute myelocytic leukemia carcinogenesis

BACKGROUND

The aim of this study is to investigate the profiles of gut microbiota and metabolites in acute myelocytic leukemia (AML) patients treated with/without chemotherapy.

METHODS

Herein, high-throughput 16S rRNA gene sequencing was performed to analysis gut microbiota profiles, and liquid chromatography and mass spectrometry were performed to analysis metabolites profiles. The correlation between gut microbiota biomarkers identified by LEfSe and differentially expressed metabolites were determined by spearman association analysis.

RESULTS

The results showed the distinguished gut microbiota and metabolites profiles between AML patients and control individuals or AML patients treated with chemotherapy. Compared to normal populations, the ratio of Firmicutes to Bacteroidetes was increased at the phylum level than that in AML patients, and LEfSe analysis identified Collinsella and Coriobacteriaceae as biomarkers of AML patients. Differential metabolite analysis indicated that, compared to AML patients, numerous differential amino acids and analogs could be observed in control individuals and AML patients treated with chemotherapy. Interestingly, spearman association analysis demonstrated that plenty of bacteria biomarkers shows statistical correlations with differentially expressed amino acid metabolites. In addition, we found that both Collinsella and Coriobacteriaceae demonstrate remarkable positive correlation with hydroxyprolyl-hydroxyproline, prolyl-tyrosine, and tyrosyl-proline.

CONCLUSION

In conclusion, our present study investigated the role of the gut-microbiome-metabolome axis in AML and revealed the possibility of AML treatment by gut-microbiome-metabolome axis in the further.

Evaluation of the Oesophagogastric Cancer-Associated Microbiome: A Systematic Review and Quality Assessment

OBJECTIVE

Oesophagogastric cancer is the fifth most common cancer worldwide, with poor survival outcomes. The role of bacteria in the pathogenesis of oesophagogastric cancer remains poorly understood.

DESIGN

A systematic search identified studies assessing the oesophagogastric cancer microbiome. The primary outcome was to identify bacterial enrichment specific to oesophagogastric cancer. Secondary outcomes included appraisal of the methodology, diagnostic performance of cancer bacteria and the relationship between oral and tissue microbiome.

RESULTS

A total of 9295 articles were identified, and 87 studies were selected for analysis. Five genera were enriched in gastric cancer: Lactobacillus, Streptococcus, Prevotella, Fusobacterium and Veillonella. No clear trends were observed in oesophageal adenocarcinoma. Streptococcus, Prevotella and Fusobacterium were abundant in oesophageal squamous cell carcinoma. Functional analysis supports the role of immune cells, localised inflammation and cancer-specific pathways mediating carcinogenesis. STORMS reporting assessment identified experimental deficiencies, considering batch effects and sources of contamination prevalent in low-biomass samples.

CONCLUSIONS

Functional analysis of cancer pathways can infer tumorigenesis within the cancer-microbe-immune axis. There is evidence that study design, experimental protocols and analytical techniques could be improved to achieve more accurate and representative results. Whole-genome sequencing is recommended to identify key metabolic and functional capabilities of candidate bacteria biomarkers.

Lipopolysaccharide exacerbates to the migration, invasion, and epithelial-mesenchymal transition of esophageal cancer cells by TLR4/NF-κB axis

Previous studies have shown the role of bacterial lipopolysaccharide (LPS) in promoting tumor progression. Our previous study found that the community richness of LPS-producing bacteria was significantly increased in the fresh stool samples of esophageal cancer (EC) patients, but the relative LPS levels and underlying mechanism in EC progression remain unknown. In this study, an case-control study found that the content of LPS was higher in serum of EC patients. Functional experiments of CCK8 assay and transwell assay showed that LPS contributed to the proliferation, migration, invasion of EC109 cells. Meanwhile, LPS induced EC109 to secrete IL-6 and TGF-β1. Western blot analysis revealed the level of TLR4 and NF-κB increased significantly after LPS treatment. Epithelial marker E-cadherin was significantly down-regulated and interstitial marker N-cadherin and Vimentin were up-regulated after LPS treatment. However, TAK242 (TLR4 inhibitor) or PDTC (NF-κB inhibitor) could eliminate the inflammatory and EMT-promoting effects of LPS. In total, our results suggested that LPS exacerbated to the migration, invasion, and epithelial-mesenchymal transition of EC109 cells by TLR4/NF-κB axis. High level LPS may have a critical effect on the occurrence and development of EC.

Characteristics of gastric cancer gut microbiome according to tumor stage and age segmentation

With the development of 16S rRNA technology, gut microbiome evaluation has been performed in many diseases, including gastrointestinal tumors. Among these cancers, gastric cancer (GC) exhibits high morbidity and mortality and has been extensively studied in its pathogenesis and diagnosis techniques. The current researches have proved that the gut microbiome may have the potential to distinguish GC patients from healthy patients. However, the change of the gut microbiome according to tumor node metastasis classification (TNM) has not been clarified. Besides, the characteristics of gut microbiome in GC patients and their ages of onset are also ambiguous. To address the above shortcomings, we investigated 226 fecal samples and divided them according to their tumor stage and onset age. The findings revealed that surgery and tumor stage can change the characteristic of GC patients' gut microbiota. In specific, the effect of surgery on early gastric cancer (EGC) was greater than that on advanced gastric cancer (AGC), and the comparison of postoperative microflora with healthy people indicated that EGC has more differential bacteria than AGC. Besides, we found that Collinsella, Blautia, Anaerostipes, Dorea, and Lachnospiraceae_ND3007_group expressed differently between EGC and AGC. More importantly, it is the first time revealed that the composition of gut microbiota in GC is different between different onset ages. KEY POINTS: •Gut microbiota of gastric cancer (GC) patients are either highly associated with TNM stage and surgery or not. It shows surgery has more significant changes in early gastric cancer (EGC) than advanced gastric cancer (AGC). •There existed specific gut microbiota between EGC and AGC which may have potential to distinguish the early or advanced GC. •Onset age of GC may influence the gut microbiota: the composition of gut microbiota of early-onset gastric cancer (EOGC) and late-onset gastric cancer (LOGC) is significantly different.

Comprehensive fecal metabolomics and gut microbiota for the evaluation of the mechanism of Panax Ginseng in the treatment of Qi-deficiency liver cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Qi deficiency liver cancer (QDLC) is an important part of liver cancer research in traditional Chinese medicine (TCM). In the course of its treatment, Panax ginseng is often selected as the main Chinese herbal medicine, and its function has special significance in the tumor treatment of Qi deficiency constitution. However, its mechanism is not clear.

AIM OF THE STUDY

The research tried to evaluate the mechanism of Panax ginseng in the treatment of QDLC through fecal metabonomics and gut microbiota on the basis of previous pharmacodynamic evaluation.

MATERIALS AND METHODS

Firstly, biomarkers and related metabolic pathways were screened and identified by metabonomics and Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Then, 16S rRNA sequencing technique was used to investigate the composition, β diversity and key differences of gut microbiota. Finally, the relationship among phenotypes, gut microbiota and fecal metabolites was comprehensively analyzed by spearman correlation coefficient.

RESULTS

31 pharmacodynamic potential biomarkers and 20 synergistic potential biomarkers of effective parts of Panax ginseng on QDLC were screened and identified by fecal metabonomics. And then, 6 major metabolic pathways were searched, including bile acid biosynthesis, unsaturated fatty acid biosynthesis, tryptophan metabolism, arachidonic acid metabolism, pyrimidine metabolism, vitamin B6 metabolism. In the study of gut microbiota, at the genus level, 25 species of bacteria with significant differences of effective parts on QDLC and 23 species of bacteria with significant differences of synergistic action of ginsenosides and polysaccharides were screened. In addition, Spearman correlation analysis showed that there was a complex potential relationship among phenotype, gut microbiota and fecal metabolites during the development of QDLC and Panax ginseng intervention, which was mainly reflected in the close potential relationship between bacteria and fecal metabolites such as bile acids, unsaturated fatty acids and indole compounds.

CONCLUSION

Through the changes of fecal endogenous metabolites and intestinal bacteria, the mechanism of Panax ginseng on QDLC were preliminarily clarified.

Helicobacter pylori promotes gastric cancer progression through the tumor microenvironment

Gastric cancer (GC) is a leading type of cancer. Although immunotherapy has yielded important recent progress in the treatment of GC, the prognosis remains poor due to drug resistance and frequent recurrence and metastasis. There are multiple known risk factors for GC, and infection with Helicobacter pylori is one of the most significant. The mechanisms underlying the associations of H. pylori and GC remain unclear, but it is well known that infection can alter the tumor microenvironment (TME). The TME and the tumor itself constitute a complete ecosystem, and the TME plays critical roles in tumor progression, metastasis, and drug resistance. H. pylori infection can act synergistically with the TME to cause DNA damage and abnormal expression of multiple genes and activation of signaling pathways. It also modulates the host immune system in ways that enhance the proliferation and metastasis of tumor cells, promote epithelial-mesenchymal transition, inhibit apoptosis, and provide energy support for tumor growth. This review elaborates myriad ways that H. pylori infections promote the occurrence and progression of GC by influencing the TME, providing new directions for immunotherapy treatments for this important disease. KEY POINTS: • H. pylori infections cause DNA damage and affect the repair of the TME to DNA damage. • H. pylori infections regulate oncogenes or activate the oncogenic signaling pathways. • H. pylori infections modulate the immune system within the TME.