Dysbiosis of Gut Microbiota Promotes Hepatocellular Carcinoma Progression by Regulating the Immune Response

Gut Microbiota, Deranged Immunity, and Hepatocellular Carcinoma

BACKGROUND

Liver cancer, particularly hepatocellular carcinoma (HCC), is a significant gastrointestinal disease with a mortality rate as high as nearly 80% within five years. The disease's pathophysiology involves deranged immune responses and bile acid metabolism, with the gut microbiota (GM) playing a crucial role. Recent research highlights the potential of GM in influencing HCC treatment outcomes, especially regarding immune checkpoint inhibitors (ICIs). However, few patients currently benefit from ICIs due to a lack of effective response biomarkers.

AIMS AND METHODS

This review aimed to explore the literature on HCC treatment issues, focusing on immune response, bile acid metabolism, and GM dysbiosis. This review included studies from PubMed, Medline, and major gastroenterology and hepatology meetings, using keywords like gut microbiota, immune system, liver cancer, and checkpoint inhibitors.

RESULTS

GM dysbiosis significantly impacts immune response and bile acid metabolism, making it a promising biomarker for ICI response. Modulating GM can enhance ICI treatment efficacy, although more research is needed to confirm its direct therapeutic benefits for HCC.

CONCLUSIONS

GM dysbiosis is integral to liver cancer pathogenesis and treatment response. Its modulation offers promising therapeutic avenues for improving HCC prognosis and response to immunotherapy.

Understanding gut dysbiosis for hepatocellular carcinoma diagnosis and treatment

The gut microbiome can play a crucial role in hepatocellular carcinoma (HCC) progression through the enterohepatic circulation, primarily acting via metabolic reprogramming and alterations in the hepatic immune microenvironment triggered by microbe-associated molecular patterns (MAMPs), metabolites, and fungi. In addition, the gut microbiome shows potential as a biomarker for early HCC diagnosis and for assessing the efficacy of immunotherapy in unresectable HCC. This review examines how gut microbiota dysbiosis, with varied functional profiles, contributes to HCCs of different etiologies. We discuss therapeutic strategies to modulate the gut microbiome including diets, antibiotics, probiotics, fecal microbiota transplantation, and nano-delivery systems, and underscore their potential as an adjunctive treatment modality for HCC.

Association between gut microbiota and hepatocellular carcinoma and biliary tract cancer: A mendelian randomization study

BACKGROUND

An increasing number of studies have begun to discuss the relationship between gut microbiota and diseases, yet there is currently a lack of corresponding articles describing the association between gut microbiota and hepatocellular carcinoma (HCC) and biliary tract cancer (BTC). This study aims to explore the relationship between them using Mendelian randomization (MR) analysis method.

AIM

To assess the relationship between gut microbiota and HCC and BTC.

METHODS

We obtained Genome-wide association study (GWAS) data for the gut microbiome from the intestinal microbiota genomic library (MiBioGen, https://mibiogen.gcc.rug.nl/). Additionally, we accessed data pertaining to HCC and BTC from the IEU open GWAS platform (https://gwas.mrcieu.ac.uk/). Our analysis employed fundamental instrumental variable analysis methods, including inverse-variance weighted, MR and Egger. To ensure the dependability of the results, we subjected the results to tests for multiple biases and heterogeneity.

RESULTS

During our investigation, we discovered 11 gut microbiota linked to an increased risk to BTC and HCC. The former included the genus Eubacterium hallii group (P = 0.017), Candidatus Soleaferrea (P = 0.034), Flavonifractor (P = 0.021), Lachnospiraceae FCS020 (P = 0.034), the order Victivallales (P = 0.018), and the class Lentisphaeria (P = 0.0.18). The latter included the genus Desulfovibrio (P = 0.042), Oscillibacter (P = 0.023), the family Coriobacteriaceae (P = 0.048), the order Coriobacteriales (P = 0.048), and the class Coriobacteriia (P = 0.048). Furthermore, in BTC, we observed 2 protective gut microbiota namely the genus Dorea (P = 0.041) and Lachnospiraceae ND3007 group (P = 0.045). All results showed no evidence of multiplicity or heterogeneity.

CONCLUSION

This study explores a causal link between gut microbiota and HCC and BTC. These insights may enhance the mechanistic knowledge of microbiota-related HCC and BTC pathways, potentially informing therapeutic strategies.

Notch Signaling Inhibition Alleviates Allergies Caused by Antarctic Krill Tropomyosin through Improving Th1/Th2 Imbalance and Modulating Gut Microbiota

Antarctic krill tropomyosin (AkTM) has been shown in mice to cause IgE-mediated food allergy. The objective of this work was to investigate the role of Notch signaling in AkTM-sensitized mice, as well as to determine the changes in gut microbiota composition and short-chain fatty acids (SCFAs) in the allergic mice. An AkTM-induced food allergy mouse model was built and N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT) was used as an γ-secretase inhibitor to inhibit the activation of Notch signaling. Food allergy indices, some key transcription factors, histologic alterations in the small intestine, and changes in gut microbiota composition were examined. The results showed that DAPT inhibited Notch signaling, which reduced AkTM-specific IgE, suppressed mast cell degranulation, decreased IL-4 but increased IFN-γ production, and alleviated allergic symptoms. Quantitative real-time PCR and Western blotting analyses revealed that expressions of Hes-1, Gata3, and IL-4 were down-regulated after DAPT treatment, accompanied by increases in T-bet and IFN-γ, indicating that Notch signaling was active in AkTM-sensitized mice and blocking it could reverse the Th1/Th2 imbalance. Expressions of key transcription factors revealed that Notch signaling could promote Th2 cell differentiation in sensitized mice. Furthermore, 16S rRNA sequencing results revealed that AkTM could alter the diversity and composition of gut microbiota in mice, leading to increases in inflammation-inducing bacteria such as Enterococcus and Escherichia-Shigella. Correlation analysis indicated that reduced SCFA concentrations in AkTM-allergic mice may be related to decreases in certain SCFA-producing bacteria, such as Clostridia_UCG-014. The changes in gut microbiota and SCFAs could be partially restored by DAPT treatment. Our findings showed that inhibiting Notch signaling could alleviate AkTM-induced food allergy by correcting Th1/Th2 imbalance and modulating the gut microbiota.

Unveiling the complex relationship between gut microbiota and liver cancer: opportunities for novel therapeutic interventions

Hepatocellular carcinoma (HCC) has been linked to the gut microbiota, with recent studies revealing the potential of gut-generated responses to influence several arms of the immune responses relevant to HCC formation. The pro- or anti-tumor effects of specific bacterial strains or gut microbiota-related metabolites, such as bile acids and short-chain fatty acids, have been highlighted in many human and animal studies. The critical role of the gut microbiota in HCC development has spurred interest in modulating the gut microbiota through dietary interventions, probiotics, and fecal microbiota transplantation as a potential strategy to improve liver cancer outcomes. Encouragingly, preclinical and clinical studies have demonstrated that modulation of the gut microbiota can ameliorate liver function, reduce inflammation, and inhibit liver tumor growth, underscoring the potential of this approach to improve HCC outcomes. As research continues to unravel the complex and dynamic mechanisms underlying the gut-liver axis, the development of safe and effective interventions to target this pathway for liver cancer prevention and treatment appears to be on the horizon, heralding a significant advance in our ongoing efforts to combat this devastating disease.

G. lucidum triterpenes restores intestinal flora balance in non-hepatitis B virus-related hepatocellular carcinoma: evidence of 16S rRNA sequencing and network pharmacology analysis

Background: Ganoderma lucidum (G. lucidum) is a popular traditional remedy medicine used in Asia to promote health and longevity, which has also been highlighted for anti-cancer effects. This study investigated the molecular pharmacological mechanism of G. lucidum triterpenes in influencing intestinal flora imbalance in non-hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) based on 16S rRNA sequencing technology and network pharmacology analysis. Methods: 16S rRNA sequencing data of fecal samples from normal controls and HCC patients were obtained from the SRA database. G. lucidum triterpenes and HCC-related targets were screened by BATMAN-TCM, ETCM, and GeneCards databases. The TCGA-LIHC dataset was downloaded through the TCGA database to analyze the differential expression of key genes. NHBV-related HCC-related transcriptome RNA sequencing dataset was downloaded via the GEO database. Results: Abundance of intestinal flora in the HBV-related HCC and NHBV-related samples was higher than that of control samples. The intestinal flora of NHBV samples was mainly enriched in apoptosis and p53 pathways. Totally, 465 G. lucidum triterpenes-related targets were intersected with 4186 HCC-related targets, yielding 176 intersected targets. Among them, apoptosis and p53 pathway factors were located at the core of the protein-protein interactions network. Ganosporelactone B, the active component of G. lucidum triterpenes, had the lowest binding free energy to CASP3. CASP3 expression were upregulated in HCC tissue samples, and had higher predictive value in NHBV-related HCC patients. Conclusion: Therefore, Ganosporelactone B, the active ingredient of G. lucidum triterpenes, improves the imbalance of intestinal flora and ultimately curtails development of NHBV-related HCC.

The Role of Gut Microbiome in Hepatocellular Carcinoma: A Systematic Review

Gut microbiome dysbiosis is common in patients with chronic liver diseases such as hepatocellular carcinoma (HCC) and plays an essential role in developing, diagnosing, and treating HCC. The purpose of this systematic review, which was carried out following the Preferred Reporting Items for Systematic Review and Meta-analyses 2020 guidelines, is to determine the role of the gut microbiome in the pathogenesis, diagnosis, and treatment of HCC. We collected and reviewed articles, including clinical trials, literature reviews, case-control studies, cross-sectional studies, cohort studies, systematic reviews, and meta-analyses, published between May 30, 2013, and May 30, 2023. The databases used to collect these articles included PubMed, Cochrane Library, Google Scholar, and ScienceDirect. After applying appropriate filters, a total of 2,969 studies were identified. They were further screened and subjected to quality assessment tools which finally yielded 17 studies included in this systematic review. This systematic review provides information regarding the gut-liver axis and the relationship between gut microbiome dysbiosis and HCC.

From Non-Alcoholic Fatty Liver Disease to Liver Cancer: Microbiota and Inflammation as Key Players

It is estimated that 25% of the world's population has non-alcoholic fatty liver disease. This disease can advance to a more severe form, non-alcoholic steatohepatitis (NASH), a disease with a greater probability of progression to cirrhosis and hepatocellular carcinoma (HCC). NASH could be characterized as a necro-inflammatory complication of chronic hepatic steatosis. The combination of factors that lead to NASH and its progression to HCC in the setting of inflammation is not clearly understood. The portal vein is the main route of communication between the intestine and the liver. This allows the transfer of products derived from the intestine to the liver and the hepatic response pathway of bile and antibody secretion to the intestine. The intestinal microbiota performs a fundamental role in the regulation of immune function, but it can undergo changes that alter its functionality. These changes can also contribute to cancer by disrupting the immune system and causing chronic inflammation and immune dysfunction, both of which are implicated in cancer development. In this article, we address the link between inflammation, microbiota and HCC. We also review the different in vitro models, as well as recent clinical trials addressing liver cancer and microbiota.

Integrated analysis reveals important differences in the gut and oropharyngeal microbiota between children with mild and severe hand, foot and mouth disease

Little is known about alternation and difference in gut microbiota between patients with mild and severe hand, foot and mouth disease (HFMD). We investigated the differences in gut and oropharynx microbiotas between mild and severe HFMD in young children and changes in bacterial profiles as the disease progresses from acute to convalescent phase. Forty-two patients with confirmed HFMD were studied, among which thirty-two had severe HFMD and ten had mild HFMD. First rectal swabs were collected from all patients at an average of 2 days (acute phase) after the onset of symptoms, and second rectal swabs were collected from 8 severe patients at day 9 (convalescent phase) after the onset. Oropharyngeal swabs were obtained from 10 patients in the acute phase and 6 in the convalescent phase. 16S rRNA sequencing was performed for all 70 samples. Compared with mild HFMD, severe HFMD exhibited significantly decreased diversity and richness of gut microbiota. Gut microbiota bacterial profiles observed in the acute and convalescent phases resembled each other, but differed from those in mild cases. Additionally, 50% of patients with severe HFMD in the acute phase harbored a dominant pathobiontic bacterial genus. However, none of patients with mild HFMD had such bacteria. Similar bacterial compositions in oropharynx microbiota were detected between mild and severe cases. Our findings indicate that severe HFMD exhibits significantly impaired diversity of gut microbiota and frequent gut and oropharyngeal inflammation-inducing bacteria. However, the results should be interpreted with caution as the number of the subjects was limited.

The gut microbiota: A new perspective for tertiary prevention of hepatobiliary and gallbladder diseases

The gut microbiota is a complex ecosystem that has coevolved with the human body for hundreds of millions of years. In the past 30 years, with the progress of gene sequencing and omics technology, the research related to gut microbiota has developed rapidly especially in the field of digestive system diseases and systemic metabolic diseases. Mechanical, biological, immune, and other factors make the intestinal flora form a close bidirectional connection with the liver and gallbladder, which can be called the "gut-liver-biliary axis." Liver and gallbladder, as internal organs of the peritoneum, suffer from insidious onset, which are not easy to detect. The diagnosis is often made through laboratory chemical tests and imaging methods, and intervention measures are usually taken only when organic lesions have occurred. At this time, some people may have entered the irreversible stage of disease development. We reviewed the literature describing the role of intestinal flora in the pathogenesis and biotherapy of hepatobiliary diseases in the past 3-5 years, including the dynamic changes of intestinal flora at different stages of the disease, as well as the signaling pathways involved in intestinal flora and its metabolites, etc. After summarizing the above contents, we hope to highlight the potential of intestinal flora as a new clinical target for early prevention, early diagnosis, timely treatment and prognosis of hepatobiliary diseases. GRAPHICAL ABSTRACT.

Cytokine concentration in peripheral blood of patients with colorectal cancer

Introduction

The role of tumour secretory cytokines and peripheral circulatory cytokines in tumour progression has received increasing attention; however, the role of tumour-related inflammatory cytokines in colorectal cancer (CRC) remains unclear. In this study, the concentrations of various cytokines in the peripheral blood of healthy controls and patients with CRC at different stages were compared.

Methods

Peripheral blood samples from 4 healthy participants and 22 colorectal cancer patients were examined. Luminex beads were used to evaluate concentration levels of 40 inflammatory cytokines in peripheral blood samples.

Results

In peripheral blood, compared with healthy controls and early stage (I + II) CRC patients, advanced CRC (III + IV) patients had increased concentrations of mononuclear/macrophage chemotactic-related proteins (CCL7, CCL8, CCL15, CCL2, and MIF), M2 polarization-related factors (IL-1β, IL-4), neutrophil chemotactic and N2 polarization-related cytokines (CXCL2, CXCL5, CXCL6, IL-8), dendritic cells (DCs) chemotactic-related proteins (CCL19, CCL20, and CCL21), Natural killer (NK) cell related cytokines (CXCL9, CXCL10), Th2 cell-related cytokines (CCL1, CCL11, CCL26), CXCL12, IL-2, CCL25, and CCL27, and decreased IFN-γ and CX3CL1 concentrations. The differential upregulation of cytokines in peripheral blood was mainly concentrated in CRC patients with distant metastasis and was related to the size of the primary tumour; however, there was no significant correlation between cytokine levels in peripheral blood and the propensity and mechanism of lymph node metastasis.

Discussion

Different types of immune cells may share the same chemokine receptors and can co-localise in response to the same chemokines and exert synergistic pro-tumour or anti-tumour functions in the tumour microenvironment. Chemokines and cytokines affect tumour metastasis and prognosis and may be potential targets for treatment.

The Effect of the Gut Microbiota on Systemic and Anti-Tumor Immunity and Response to Systemic Therapy against Cancer

Gut microbiota can have opposing functions from pro-tumorigenic to anti-tumorigenic effects. Increasing preclinical and clinical evidence suggests that the intestinal microbiota affects cancer patients’ response to immune checkpoint inhibitors (ICIs) immunotherapy, such as anti-programmed cell death protein 1 (PD-1) and its ligand (PD-L1) and anti-cytotoxic T lymphocyte-associated protein 4 (CTLA-4). Microbiota-induced inflammation possibly contributes to tumor growth and cancer development. Microbiota-derived metabolites can also be converted to carcinogenic agents related to genetic mutations and DNA damage in organs such as the colon. However, other attributes of microbiota, such as greater diversity and specific bacterial species and their metabolites, are linked to better clinical outcomes and potentially improved anti-tumor immunity. In addition, the intratumoral microbial composition strongly affects T-cell-mediated cytotoxicity and anti-tumor immune surveillance, adding more complexity to the cancer-microbiome-immune axis. Despite the emerging clinical evidence for the activity of the gut microbiota in immuno-oncology, the fundamental mechanisms of such activity are not well understood. This review provides an overview of underlying mechanisms by which the gut microbiota and its metabolites enhance or suppress anti-tumor immune responses. Understanding such mechanisms allows for better design of microbiome-specific treatment strategies to improve the clinical outcome in cancer patients undergoing systemic therapy.

Utilizing Gut Microbiota to Improve Hepatobiliary Tumor Treatments: Recent Advances

Hepatobiliary tumors, which include cholangiocarcinoma, hepatocellular carcinoma (HCC), and gallbladder cancer, are common cancers that have high morbidity and mortality rates and poor survival outcomes. In humans, the microbiota is comprised of symbiotic microbial cells (10-100 trillion) that belong to the bacterial ecosystem mainly residing in the gut. The gut microbiota is a complicated group that can largely be found in the intestine and has a dual role in cancer occurrence and progression. Previous research has focused on the crucial functions of the intestinal microflora as the main pathophysiological mechanism in HCC development. Intestinal bacteria produce a broad range of metabolites that exhibit a variety of pro- and anticarcinogenic effects on HCC. Therefore, probiotic alteration of the gut microflora could promote gut flora balance and help prevent the occurrence of HCC. Recent evidence from clinical and translational studies suggests that fecal microbiota transplant is one of the most successful therapies to correct intestinal bacterial imbalance. We review the literature describing the effects and mechanisms of the microbiome in the gut in the context of HCC, including gut bacterial metabolites, probiotics, antibiotics, and the transplantation of fecal microbiota, and discuss the potential influence of the microbiome environment on cholangiocarcinoma and gallbladder cancer. Our findings are expected to reveal therapeutic targets for the prevention of hepatobiliary tumors, and the development of clinical treatment strategies, by emphasizing the function of the gut microbiota.

Integrated Analysis of the Alterations in Gut Microbiota and Metabolites of Mice Induced After Long-Term Intervention With Different Antibiotics

Objectives

We aimed to study the effect of antibiotic-induced disruption of gut microbiome on host metabolomes and inflammatory responses after long-term use of antibiotics.

Methods

A total of three groups of 3-week-old female C57BL/6 mice (n = 44) were continuously treated with vancomycin (VAN), polymyxin B (PMB), or water, respectively, for up to 28 weeks. Fecal samples collected at different time points were analyzed by bacterial 16S rRNA gene sequencing and untargeted metabolomics by ultraperformance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC Q-TOF MS). Serum cytokines (IFN-γ, IL-2, IL-10, IL-13, IL-17A, and TNF-α) were determined by multiplex immunoassay.

Results

Treatment by VAN or PMB did not affect the average body weight of mice. However, a heavier caecum observed in VAN-treated mice. Compared with PMB-treated and control mice, VAN treatment induced more rapid dysbiosis of gut microbiota and dysmetabolism. Instead of Bacteroides, VAN-treated mice had a compositional shift to Proteobacteria and its species Escherichia coli and Verrucomicrobia and its species Akkermansia muciniphila. The shift was accompanied by decreased richness and diversity in microbiota. PMB-treated mice had an increased Firmicutes, and the diversity was shortly increased and further decreased to the baseline. Decreased levels of short-chain and long-chain fatty acids, bile acids, L-arginine, dopamine, L-tyrosine, and phosphatidylcholine (all p < 0.05) were observed in VAN-treated mice. In contrast, significantly increased levels of amino acids including L-aspartic acid, beta-alanine, 5-hydroxy-L-tryptophan, L-glutamic acid, and lysophosphatidylcholines (all p < 0.05) were found. These changes occurred after 3-week treatment and remained unchanged up to 28 weeks. For PMB-treated mice, metabolites involved in the metabolic pathway of vitamin B6 were decreased, whereas glycocholic acid and chenodeoxycholic acid were increased (all p < 0.05). After 8-week treatment, VAN-treated mice had significantly higher levels of serum IFN-γ, IL-13, and IL-17A, and PMB-treated mice had higher levels of IL-13 and IL-17 compared to control mice. At 28-week treatment, only IL-17A remained high in PMB-treated mice.

Conclusion

This study showed that the antibiotic-induced alterations in gut microbiota contribute to host inflammatory responses through the change in metabolic status, which are likely related to the type, rather than timing of antibiotic used.