Gut Microbiota Modulation of Efficacy and Toxicity of Cancer Chemotherapy and Immunotherapy

Strategies for treating the cold tumors of cholangiocarcinoma: core concepts and future directions

Cholangiocarcinoma (CCA) is a rare type of digestive tract cancer originating from the epithelial cells of the liver and biliary tract. Current treatment modalities for CCA, such as chemotherapy and radiation therapy, have demonstrated limited efficacy in enhancing survival rates. Despite the revolutionary potential of immunotherapy in cancer management, its application in CCA remains restricted due to the minimal infiltration of immune cells in these tumors, rendering them cold and unresponsive to immune checkpoint inhibitors (ICIs). Cancer cells within cold tumors deploy various mechanisms for evading immune attack, thus impeding clinical management. Recently, combination immunotherapy has become increasingly essential to comprehend the mechanisms underlying cold tumors to enhance a deficient antitumor immune response. Therefore, a thorough understanding of the knowledge on the combination immunotherapy of cold CCA is imperative to leverage the benefits of immunotherapy in treating patients. Moreover, gut microbiota plays an essential role in the immunotherapeutic responses in CCA. In this review, we summarize the current concepts of immunotherapy in CCA and clarify the intricate dynamics within the tumor immune microenvironment (TIME) of CCA. We also delve into the evasion mechanisms employed by CCA tumors against the anti-tumor immune responses. The context of combination immunotherapies in igniting cold tumors of CCA and the critical function of gut microbiota in prompting immune responses have also been annotated. Furthermore, we have proposed future directions in the realm of CCA immunotherapy, aiming to improve the clinical prognosis of CCA patients.

Exosomes-mediated retinoic acid disruption: A link between gut microbiota depletion and impaired spermatogenesis

Gut microbiota symbiosis faces enormous challenge with increasing exposure to drugs such as environmental poisons and antibiotics. The gut microbiota is an important component of the host microbiota and has been proven to be involved in regulating spermatogenesis, but the molecular mechanism is still unclear. A male mouse model with gut microbiota depletion/dysbiosis was constructed by adding combined antibiotics to free drinking water, and reproductive parameters such as epididymal sperm count, testicular weight and paraffin sections were measured. Testicular transcriptomic and serum metabolomic analyses were performed to reveal the molecular mechanism of reproductive dysfunction induced by gut microbiota dysbiosis in male mice.This study confirms that antibiotic induced depletion of gut microbiota reduces sperm count in the epididymis and reduces germ cells in the seminiferous tubules in male mice. Further study showed that exosomes isolated from microbiota-depleted mice led to abnormally high levels of retinoic acid and decrease in the number of germ cells in the seminiferous tubules and sperm in the epididymis. Finally, abnormally high levels of retinoic acid was confirmed to disrupted meiotic processes, resulting in spermatogenesis disorders. This study proposed the concept of the gut microbiota-exosome-retinoic acid-testicular axis and demonstrated that depletion of the gut microbiota caused changes in the function of exosomes, which led to abnormal retinoic acid metabolism in the testis, thereby impairing meiosis and spermatogenesis processes.

Microbes in the tumor microenvironment: New additions to break the tumor immunotherapy dilemma

Immunotherapies currently used in clinical practice are unsatisfactory in terms of therapeutic response and toxic side effects, and therefore new immunotherapies need to be explored. Intratumoral microbiota (ITM) exists in the tumor environment (TME) and reacts with its components. On the one hand, ITM promotes antigen delivery to tumor cells or provides cross-antigens to promote immune cells to attack tumors. On the other hand, ITM affects the activity of immune cells and stromal cells. We also summarize the dialog pathways by which ITM crosstalks with components within the TME, particularly the interferon pathway. This interaction between ITM and TME provides new ideas for tumor immunotherapy. By analyzing the bidirectional role of ITM in TME and combining it with its experimental and clinical status, we summarized the adjuvant role of ITM in immunotherapy. We explored the potential applications of using ITM as tumor immunotherapy, such as a healthy diet, fecal transplantation, targeted ITM, antibiotics, and probiotics, to provide a new perspective on the use of ITM in tumor immunotherapy.

Updated perspectives on the contribution of the microbiome to the pathogenesis of mucositis using the MASCC/ISOO framework

Advances in the treatment of cancer have significantly improved mortality rates; however, this has come at a cost, with many treatments still limited by their toxic side effects. Mucositis in both the mouth and gastrointestinal tract is common following many anti-cancer agents, manifesting as ulcerative lesions and associated symptoms throughout the alimentary tract. The pathogenesis of mucositis was first defined in 2004 by Sonis, and almost 20 years on, the model continues to be updated reflecting ongoing research initiatives and more sophisticated analytical techniques. The most recent update, published by the Multinational Association for Supportive Care in Cancer and the International Society for Oral Oncology (MASCC/ISOO), highlights the numerous co-occurring events that underpin mucositis development. Most notably, a role for the ecosystem of microorganisms that reside throughout the alimentary tract (the oral and gut microbiota) was explored, building on initial concepts proposed by Sonis. However, many questions remain regarding the true causal contribution of the microbiota and associated metabolome. This review aims to provide an overview of this rapidly evolving area, synthesizing current evidence on the microbiota's contribution to mucositis development and progression, highlighting (i) components of the 5-phase model where the microbiome may be involved, (ii) methodological challenges that have hindered advances in this area, and (iii) opportunities for intervention.

Gut microbiota affects the activation of STING pathway and thus participates in the progression of colorectal cancer

BACKGROUND

More and more studies showed that gut microbiota was closely related to the development of colorectal cancer (CRC). However, the specific pathway of gut microbiota regulating CRC development is still unknown.

METHODS

We collected fecal samples from 14 CRC patients and 20 normal volunteers for 16 S sequencing analysis. At the same time, 14 CRC patients' tumors and their adjacent tissues were collected for the detection of STING pathway related protein level. Mice were injected with azoxymethane (AOM) to establish an animal model of CRC, and antibiotics were given at the same time to evaluate the influence of gut microbiota on STING pathway and whether it was involved in regulating the tumor development of CRC mice.

RESULTS

The sequencing results showed that compared with the normal group, the gut microbiota gut microbiota of CRC patients changed significantly at different species classification levels. At the level of genus, Akkermansia, Ligilactobacillus and Subdoligranulum increased the most in CRC patients, while Bacteroides and Dialister decreased sharply. The expression of STING-related protein was significantly down-regulated in CRC tumor tissues. Antibiotic treatment of CRC mice can promote the development of tumor and inhibit the activation of STING pathway.

CONCLUSION

Gut microbiota participates in CRC progress by mediating STING pathway activation.

Pediococcus pentosaceus PP34 Ameliorates 5-Fluorouracil-Induced Intestinal Mucositis via Inhibiting Oxidative Stress and Restoring the Gut Microbiota

Chemotherapy-induced intestinal mucositis based on 5-fluorouracil (5-FU) slows down the progress of cancer treatment and causes significant suffering to patients. Pediococcus pentosaceus (P. pentosaceus), as a type of LAB, has a range of probiotic properties, including antioxidant, immune benefits, and cholesterol-lowering effects, which are attracting increasing attention. However, studies on the protective effect of P. pentosaceus against chemotherapeutic-induced intestinal mucositis caused by 5-FU remain unclear. Therefore, this study aimed to investigate the potential relieving effects of P. pentosaceus PP34 on 5-FU-induced intestinal mucositis and its mechanism. In the present study, a P. pentosaceus PP34 solution (2 × 109 CFU/mL) was administered daily by gavage followed by intraperitoneal injection of 5-FU to model intestinal mucositis. The body weight, serum biochemical indices, jejunal pathological organization, and expression levels of inflammatory cytokines in the jejunum were examined. The results indicated that the mice induced with 5-FU developed typical intestinal mucositis symptoms and histopathological changes with intense inflammatory and oxidative responses. Moreover, the gut microbiota was disturbed, while PP34 effectively decreased the oxidative reactions and the expression levels of inflammatory mediators and regulated the gut microbiota in 5-FU-exposed mice. Taken together, the study indicated that P. pentosaceus PP34 ameliorates 5-Fluorouracil-induced intestinal mucositis via inhibiting oxidative stress and restoring the gut microbiota.

Advancements in the impact of human microbiota and probiotics on leukemia

The human gut microbiota is a complex ecosystem that plays a crucial role in promoting the interaction between the body and its environment. It has been increasingly recognized that the gut microbiota has diverse physiological functions. Recent studies have shown a close association between the gut microbiota and the development of certain tumors, including leukemia. Leukemia is a malignant clonal disease characterized by the uncontrolled growth of one or more types of blood cells, which is the most common cancer in children. The imbalance of gut microbiota is linked to the pathological mechanisms of leukemia. Probiotics, which are beneficial microorganisms that help maintain the balance of the host microbiome, play a role in regulating gut microbiota. Probiotics have the potential to assist in the treatment of leukemia and improve the clinical prognosis of leukemia patients. This study reviews the relationship between gut microbiota, probiotics, and the progression of leukemia based on current research. In addition, utilizing zebrafish leukemia models in future studies might reveal the specific mechanisms of their interactions, thereby providing new insights into the clinical treatment of leukemia. In conclusion, further investigation is still needed to fully understand the accurate role of microbes in leukemia.

Identification and Application of Emerging Biomarkers in Treatment of Non-Small-Cell Lung Cancer: Systematic Review

Non-small-cell lung cancer (NSCLC) comprises approximately 85% of all lung cancer cases, often diagnosed at advanced stages, which diminishes the effective treatment options and survival rates. This systematic review assesses the utility of emerging biomarkers-circulating tumor DNA (ctDNA), microRNAs (miRNAs), and the blood tumor mutational burden (bTMB)-enhanced by next-generation sequencing (NGS) to improve the diagnostic accuracy, prognostic evaluation, and treatment strategies in NSCLC. Analyzing data from 37 studies involving 10,332 patients from 2020 to 2024, the review highlights how biomarkers like ctDNA and PD-L1 expression critically inform the selection of personalized therapies, particularly beneficial in the advanced stages of NSCLC. These biomarkers are critical for prognostic assessments and in dynamically adapting treatment plans, where high PD-L1 expression and specific genetic mutations (e.g., ALK fusions, EGFR mutations) significantly guide the use of targeted therapies and immunotherapies. The findings recommend integrating these biomarkers into standardized clinical pathways to maximize their potential in enhancing the treatment precision, ultimately fostering significant advancements in oncology and improving patient outcomes and quality of life. This review substantiates the prognostic and predictive value of these biomarkers and emphasizes the need for ongoing innovation in biomarker research.

Current landscape of fecal microbiota transplantation in treating depression

Depression, projected to be the predominant contributor to the global disease burden, is a complex condition with diverse symptoms including mood disturbances and cognitive impairments. Traditional treatments such as medication and psychotherapy often fall short, prompting the pursuit of alternative interventions. Recent research has highlighted the significant role of gut microbiota in mental health, influencing emotional and neural regulation. Fecal microbiota transplantation (FMT), the infusion of fecal matter from a healthy donor into the gut of a patient, emerges as a promising strategy to ameliorate depressive symptoms by restoring gut microbial balance. The microbial-gut-brain (MGB) axis represents a critical pathway through which to potentially rectify dysbiosis and modulate neuropsychiatric outcomes. Preclinical studies reveal that FMT can enhance neurochemicals and reduce inflammatory markers, thereby alleviating depressive behaviors. Moreover, FMT has shown promise in clinical settings, improving gastrointestinal symptoms and overall quality of life in patients with depression. The review highlights the role of the gut-brain axis in depression and the need for further research to validate the long-term safety and efficacy of FMT, identify specific therapeutic microbial strains, and develop targeted microbial modulation strategies. Advancing our understanding of FMT could revolutionize depression treatment, shifting the paradigm toward microbiome-targeting therapies.

Ginsenoside Rh4 alleviates gastrointestinal mucositis and enhances chemotherapy efficacy through modulating gut microbiota

BACKGROUND

Gastrointestinal mucositis stands as one of the most severe side effects of irinotecan (CPT-11). however, only palliative treatment is available at present. Therefore, there is an urgent need for adjunctive medications to alleviate the side effects of CPT-11.

PURPOSE

In this study, our objective was to explore whether ginsenoside Rh4 could serve as a modulator of the gut microbiota and an adjunctive agent for chemotherapy, thereby alleviating the side effects of CPT-11 and augmenting its anti-tumor efficacy.

STUDY DESIGN

A CPT-11-induced gastrointestinal mucositis model was used to investigate whether ginsenoside Rh4 alleviated CPT-11-induced gastrointestinal mucositis and enhanced the anti-tumor activity of CPT-11.

METHODS

In this study, we utilized CT26 cells to establish a xenograft tumor model, employing transcriptomics, genomics, and metabolomics techniques to investigate the impact of ginsenoside Rh4 on CPT-11-induced gastrointestinal mucositis and the effect on the anti-tumor activity of CPT-11. Furthermore, we explored the pivotal role of gut microbiota and their metabolites through fecal microbiota transplantation (FMT) experiments and supplementation of the key differential metabolite, hyodeoxycholic acid (HDCA).

RESULTS

The results showed that ginsenoside Rh4 repaired the impairment of intestinal barrier function and restored intestinal mucosal homeostasis in a gut microbiota-dependent manner. Ginsenoside Rh4 treatment modulated gut microbiota diversity and upregulated the abundance of beneficial bacteria, especially Lactobacillus_reuteri and Akkermansia_muciniphila, which further regulated bile acid biosynthesis, significantly promoted the production of the beneficial secondary bile acid hyodeoxycholic acid (HDCA), thereby alleviating CPT-11-induced gut microbiota dysbiosis. Subsequently, ginsenoside Rh4 further alleviated gastrointestinal mucositis through the TGR5-TLR4-NF-κB signaling pathway. On the other hand, ginsenoside Rh4 combination therapy could further reduce the weight and volume of colon tumors, promote tumor cell apoptosis, and enhance the anti-tumor activity of CPT-11 by inhibiting the PI3K-Akt signaling pathway, thus exerting a synergistic anti-tumor effect.

CONCLUSION

In summary, our findings confirm that ginsenoside Rh4 can alleviate CPT-11-induced gastrointestinal mucositis and enhance the anti-tumor activity of CPT-11 by modulating gut microbiota and its related metabolites. Our study validates the potential of ginsenoside Rh4 as a modulator of the gut microbiota and an adjunctive agent for chemotherapy, offering new therapeutic strategies for addressing chemotherapy side effects and improving chemotherapy efficacy.

Gut-Derived Exosomes Mediate the Microbiota Dysbiosis-Induced Spermatogenesis Impairment by Targeting Meioc in Mice

Diseases like obesity and intestinal inflammation diseases are accompanied by dysbiosis of the gut microbiota (DSGM), which leads to various complications, including systemic metabolic disorders. DSGM reportedly impairs the fertility of male mice; however, the regulatory mechanism is unclear. Exosomes are molecular mediators of intercellular communication, but the regulation of spermatogenesis by non-reproductive tissue-originated exosomes remains unknown. The present study shows that DSGM altered the miRNA expression profile of mouse circulating exosomes and impaired spermatogenesis. Moreover, the single-cell sequencing results indicate that circulating exosomes from mice with DSGM impaired spermatogenesis, while circulating exosomes from wild mice improved spermatogenesis by promoting meiosis. Further study demonstrates that DSGM leads to abnormal upregulation of miR-211-5p in gut-derived circulating exosomes, which inhibited the expression of meiosis-specific with coiled-coil domain (Meioc) in the testes and impaired spermatogenesis by disturbing meiosis process. In summary, this study defines the important role of gut-derived exosomes in connecting the "gut-testis" axis.

[Oncology in French Guiana: A challenge to win]

French Guiana is an equatorial, multicultural, overseas territory in South America. The region is unique: a wealthy country with a universal healthcare system, but significant poverty, which bears little resemblance to its neighbors Brazil and Suriname. Cancer is the second leading cause of death. The incidence of cancer is lower than in France, stages are generally more advanced and the prognosis worse. To date, oncology has been organized through a joint venture between local institutions and healthcare professionals and a cancer center in mainland France, in line with the recommendations of the Institut National du Cancer. The implementation of a medical project and a complete medical studies curriculum in French Guiana is a tremendous opportunity for the development of oncology. The main challenges are consolidating medical care for patients, quality control, genetic oncology, molecular biology, implementation of radiotherapy and nuclear medicine, clinical and translational research, and teaching programs. Working in oncology in French Guiana is exciting because of the scientific interest (particular characteristics of cancers, notably the role of viral or micro-organism-induced carcinogenesis, genetic factors in these populations with African and Asian roots, and the importance of a public health policy) and human interest (patients from different cultures; all of them bring original approaches to health and illness that need to be deciphered in order to offer quality care). This requires the support of healthcare professionals who are enthusiastic about this unique adventure.

Salivary microbiome is associated with the response to chemoradiotherapy in initially inoperable patients with esophageal squamous cell carcinoma

Background

The salivary microbiome may interact with chemoradiotherapy through dynamic changes in microbial composition and systemic immunity. We aimed to explore the association between the salivary microbiome and response to chemoradiotherapy in initially inoperable patients with local advanced esophageal squamous cell carcinoma (LAESCC).

Methods

Salivary and peripheral blood samples were collected before and after chemoradiotherapy. The microbiome and metabolic pathways were analyzed by 16S ribosomal RNA sequencing and liquid chromatography tandem mass spectrometry/Mass spectrometry analyses.

Results

The salivary microbiome exhibited characteristic variations between patients and healthy controls. A significant correlation was found between Prevotella_salivae, Saccharibacteria_TM7_G3_bacterium_HMT_351, and Veillonellaceae_G1_bacterium_HMT_129 and pathological complete response (pCR) in initially inoperable patients who underwent surgery. The PICRUSt suggested that immune diseases and cell motility were different in tumor compared to normal groups. KEGG enrichment analysis showed enriched lipid metabolism, signal transduction, and membrane transport in the tumor group. CD3+CD8 T cells, IL6, IL10, and IFNγ exhibited an increasing trend during the treatment process of chemoradiotherapy.

Conclusions

Our study demonstrated that variations in specific saliva taxa associated with host immunomodulatory cells and cytokines could be promising for early efficacy prediction of chemoradiotherapy in initially inoperable patients with LAESCC.

Diagnosis and management of immune mediated liver injury from checkpoint inhibitors

PURPOSE OF REVIEW

The aim is to summarize the latest data on the incidence, clinical manifestations, and management of immune- mediated liver injury from checkpoint inhibitors (ILICI).

RECENT FINDINGS

ILICI develops in 10-15% of oncology patients receiving immunotherapy with most having asymptomatic serum aminotransferase and/or alkaline phosphatase elevations. Most grade 1-2 ILICI patients improve with drug discontinuation and/or short-term oral corticosteroids. In contrast, the 2-3% with grade 3/4 hepatotoxicity frequently require oral or intravenous corticosteroids and some are hospitalized to initiate further immunosuppression with mycophenolate mofetil or azathioprine. Liver biopsy is generally reserved for patients with atypical features or those with severe hepatotoxicity who fail to respond to treatment. Up to 3% of ILICI patients with a cholestatic profile have MRI evidence of intra or extrahepatic cholangitis that responds poorly to immunosuppression. Most ILICI patients improve during follow-up and liver-related death is very uncommon (<1%). Up to 30% of rechallenged ILICI patients develop recurrent hepatotoxicity with a shorter latency.

SUMMARY

ILICI is increasingly encountered by gastroenterologists evaluating oncology patients with abnormal liver biochemistries. A stepwise approach to exclude viral hepatitis, alcohol, hepatic metastases, and pancreaticobiliary disease is recommended. The majority of ILICI patients fully recover with ICI discontinuation and short-term corticosteroids or a second line immunosuppressant.

Nanoparticles for efficient drug delivery and drug resistance in glioma: New perspectives

Gliomas are the most common primary tumors of the central nervous system, with glioblastoma multiforme (GBM) having the highest incidence, and their therapeutic efficacy depends primarily on the extent of surgical resection and the efficacy of postoperative chemotherapy. The role of the intracranial blood-brain barrier and the occurrence of the drug-resistant gene O6-methylguanine-DNA methyltransferase have greatly limited the efficacy of chemotherapeutic agents in patients with GBM and made it difficult to achieve the expected clinical response. In recent years, the rapid development of nanotechnology has brought new hope for the treatment of tumors. Nanoparticles (NPs) have shown great potential in tumor therapy due to their unique properties such as light, heat, electromagnetic effects, and passive targeting. Furthermore, NPs can effectively load chemotherapeutic drugs, significantly reduce the side effects of chemotherapeutic drugs, and improve chemotherapeutic efficacy, showing great potential in the chemotherapy of glioma. In this article, we reviewed the mechanisms of glioma drug resistance, the physicochemical properties of NPs, and recent advances in NPs in glioma chemotherapy resistance. We aimed to provide new perspectives on the clinical treatment of glioma.

Kefir peptides mitigate bleomycin-induced pulmonary fibrosis in mice through modulating oxidative stress, inflammation and gut microbiota

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive and life-threatening lung disease with high mortality rates. The limited availability of effective drugs for IPF treatment, coupled with concerns regarding adverse effects and restricted responsiveness, underscores the need for alternative approaches. Kefir peptides (KPs) have demonstrated antioxidative, anti-inflammatory, and antifibrotic properties, along with the capability to modulate gut microbiota. This study aims to investigate the impact of KPs on bleomycin-induced pulmonary fibrosis.

METHODS

Mice were treated with KPs for four days, followed by intratracheal injection of bleomycin for 21 days. Comprehensive assessments included pulmonary functional tests, micro-computed tomography (µ-CT), in vivo image analysis using MMPsense750, evaluation of inflammation- and fibrosis-related gene expression in lung tissue, and histopathological examinations. Furthermore, a detailed investigation of the gut microbiota community was performed using full-length 16 S rRNA sequencing in control mice, bleomycin-induced fibrotic mice, and KPs-pretreated fibrotic mice.

RESULTS

In KPs-pretreated bleomycin-induced lung fibrotic mice, notable outcomes included the absence of significant bodyweight loss, enhanced pulmonary functions, restored lung tissue architecture, and diminished thickening of inter-alveolar septa, as elucidated by morphological and histopathological analyses. Concurrently, a reduction in the expression levels of oxidative biomarkers, inflammatory factors, and fibrotic indicators was observed. Moreover, 16 S rRNA sequencing demonstrated that KPs pretreatment induced alterations in the relative abundances of gut microbiota, notably affecting Barnesiella_intestinihominis, Kineothrix_alysoides, and Clostridium_viride.

CONCLUSIONS

Kefir peptides exerted preventive effects, protecting mice against bleomycin-induced lung oxidative stress, inflammation, and fibrosis. These effects are likely linked to modifications in the gut microbiota community. The findings highlight the therapeutic potential of KPs in mitigating pulmonary fibrosis and advocate for additional exploration in clinical settings.

Microbiome and cancer: from mechanistic implications in disease progression and treatment to development of novel antitumoral strategies

Cancer is a very aggressive disease and one of mankind's most important health problems, causing numerous deaths each year. Its etiology is complex, including genetic, gender-related, infectious diseases, dysbiosis, immunological imbalances, lifestyle, including dietary factors, pollution etc. Cancer patients also become immunosuppressed, frequently as side effects of chemotherapy and radiotherapy, and prone to infections, which further promote the proliferation of tumor cells. In recent decades, the role and importance of the microbiota in cancer has become a hot spot in human biology research, bringing together oncology and human microbiology. In addition to their roles in the etiology of different cancers, microorganisms interact with tumor cells and may be involved in modulating their response to treatment and in the toxicity of anti-tumor therapies. In this review, we present an update on the roles of microbiota in cancer with a focus on interference with anticancer treatments and anticancer potential.

Cervicovaginal microbiota: a promising direction for prevention and treatment in cervical cancer

Cervical cancer is a common malignancy in women, with high incidence rate and mortality. Persistent infection of high-risk human papillomavirus (HPV) is the most important risk factor for cervical cancer and precancerous lesions. Cervicovaginal microbiota (CVM) plays an essential role in the defense of HPV infections and prevention of subsequent lesions. Dominance of Lactobacillus is the key of CVM homeostasis, which can be regulated by host, exogenous and endogenous factors. Dysbiosis of CVM, including altered microbial, metabolic, and immune signatures, can contribute to persist HPV infection, leading to cervical cancer. However, there is no evidence of the causality between CVM and cervical cancer, and the underlying mechanism remains unexplored. Considering the close correlation between CVM dysbiosis and persistent HPV infection, this review will overview CVM, its role in cervical cancer development and related mechanisms, and the prospects for therapeutic applications.

Diaphorobacter nitroreducens synergize with oxaliplatin to reduce tumor burden in mice with lung adenocarcinoma

Lung adenocarcinoma (LADC) is the most common lung cancer and the leading cause of cancer-related deaths globally. Accumulating evidence suggests that the gut microbiota regulates the host response to chemotherapeutic drugs and can be targeted to reduce the toxicity of current chemotherapeutic agents. However, the effect of Diaphorobacter nitroreducens synergized with oxaliplatin on the gut microbiota and their impact on LADC have never been explored. This study aimed to evaluate the anti-cancer effects of D. nitroreducens, oxaliplatin, and their combined treatment on tumor growth in tumor-bearing mice. The composition of gut microbiota and the immune infiltration of tumors were evaluated by using 16S rRNA gene high-throughput sequencing and immunofluorescence, respectively. The inhibitory effect of the combination treatment with D. nitroreducens and oxaliplatin was significantly stronger than that of oxaliplatin alone in tumor-bearing mice. Furthermore, we observed that the combination treatment significantly increased the relative abundance of Lactobacillus and Akkermansia in the gut microbiota. Meanwhile, the combination treatment significantly increased the proportions of macrophage but decreased the proportion of regulatory T cells in the LADC tumor tissues of mice. These findings underscored the relationship between D. nitroreducens and the gut microbiota-immune cell-LADC axis, highlighting potential therapeutic avenues for LADC treatment.

IMPORTANCE

Oxaliplatin is widely used as an effective chemotherapeutic agent in cancer treatment, but its side effects and response rate still need to be improved. Conventional probiotics potentially benefit cancer chemotherapy by regulating gut microbiota and tumor immune infiltration. This study was novel in reporting a more significant inhibitory effect of Diaphorobacter nitroreducens on lung adenocarcinoma (LADC) cells compared with common traditional probiotics and validating its potential as an adjuvant therapy for LADC chemotherapy in mice. This study investigated the impact of D. nitroreducens combined with oxaliplatin on the gut microbiota and immune infiltration of tumors as a potential mechanism to improve anticancer effects.

Past, present, and future of microbiome-based therapies

Technological advances in studying the human microbiome in depth have enabled the identification of microbial signatures associated with health and disease. This confirms the crucial role of microbiota in maintaining homeostasis and the host health status. Nowadays, there are several ways to modulate the microbiota composition to effectively improve host health; therefore, the development of therapeutic treatments based on the gut microbiota is experiencing rapid growth. In this review, we summarize the influence of the gut microbiota on the development of infectious disease and cancer, which are two of the main targets of microbiome-based therapies currently being developed. We analyze the two-way interaction between the gut microbiota and traditional drugs in order to emphasize the influence of gut microbial composition on drug effectivity and treatment response. We explore the different strategies currently available for modulating this ecosystem to our benefit, ranging from 1st generation intervention strategies to more complex 2nd generation microbiome-based therapies and their regulatory framework. Lastly, we finish with a quick overview of what we believe is the future of these strategies, that is 3rd generation microbiome-based therapies developed with the use of artificial intelligence (AI) algorithms.

The interaction between intratumoral bacteria and metabolic distortion in hepatocellular carcinoma

BACKGROUND

Intratumoral bacteria might play essential roles in tumorigenesis in different cancer types. However, its features and potential roles in hepatocellular carcinoma (HCC) are largely unknown.

METHODS

In this study, we assessed bacterial RNA by 16S rRNA fluorescence in situ hybridization and detected bacterial lipopolysaccharide (LPS) via immunohistochemistry. Hepa1-6 cells were used to establish orthotopic HCC models in mice. 2bRAD sequencing for microbiome was performed to determine the intratumoral bacterial characteristics, and liquid chromatography-mass spectrometry was conducted to explore the metabolic profile. The potential association between different intratumoral microbiota and metabolites were evaluated.

RESULTS

We detected bacterial 16S rRNA and LPS in HCC tissues from the patients with HCC. In HCC mouse model, we found that the intratumor bacteria in HCC tissues were significantly different to adjacent nontumor tissues. Furthermore, we observed different metabolites in HCC tissues and adjacent nontumor tissues, such as N-acetyl-D-glucosamine and a-lactose. Our results showed that several bacteria were significantly associated with metabolites, such as Pseudomonas koreensis, which was positively correlated with N-acetyl-D-glucosamine and negatively correlated with citrulline.

CONCLUSIONS

This study confirmed the close association between different bacteria and metabolites, which might provide novel opportunities for developing new biomarkers and therapeutic targets for HCC.

The emerging role of the gut microbiome in cancer cell plasticity and therapeutic resistance

Resistance to therapeutic agents is one of the major challenges in cancer therapy. Generally, the focus is given to the genetic driver, especially the genetic mutation behind the therapeutic resistance. However, non-mutational mechanisms, such as epigenetic modifications, and TME alteration, which is mainly driven by cancer cell plasticity, are also involved in therapeutic resistance. The concept of plasticity mainly relies on the conversion of non-cancer stem cells (CSCs) to CSCs or epithelial-to-mesenchymal transition via different mechanisms and various signaling pathways. Cancer plasticity plays a crucial role in therapeutic resistance as cancer cells are able to escape from therapeutics by shifting the phenotype and thereby enhancing tumor progression. New evidence suggests that gut microbiota can change cancer cell characteristics by impacting the mechanisms involved in cancer plasticity. Interestingly, gut microbiota can also influence the therapeutic efficacy of anticancer drugs by modulating the mechanisms involved in cancer cell plasticity. The gut microbiota has been shown to reduce the toxicity of certain clinical drugs. Here, we have documented the critical role of the gut microbiota on the therapeutic efficacy of existing anticancer drugs by altering the cancer plasticity. Hence, the extended knowledge of the emerging role of gut microbiota in cancer cell plasticity can help to develop gut microbiota-based novel therapeutics to overcome the resistance or reduce the toxicity of existing drugs. Furthermore, to improve the effectiveness of therapy, it is necessary to conduct more clinical and preclinical research to fully comprehend the mechanisms of gut microbiota.

Role of circular RNAs and gut microbiome in gastrointestinal cancers and therapeutic targets

Gastrointestinal cancers are a huge worldwide health concern, which includes a wide variety of digestive tract cancers. Circular RNAs (circRNAs), a kind of non-coding RNA (ncRNAs), are a family of single-stranded, covalently closed RNAs that have become recognized as crucial gene expression regulators, having an impact on several cellular functions in cancer biology. The gut microbiome, which consists of several different bacteria, actively contributes to the regulation of host immunity, inflammation, and metabolism. CircRNAs and the gut microbiome interact significantly to greatly affect the growth of GI cancer. Several studies focus on the complex functions of circRNAs and the gut microbiota in GI cancers, including esophageal cancer, colorectal cancer, gastric cancer, hepatocellular cancer, and pancreatic cancer. It also emphasizes how changed circRNA expression profiles and gut microbiota affect pathways connected to malignancy as well as how circRNAs affect hallmarks of gastrointestinal cancers. Furthermore, circRNAs and gut microbiota have been recommended as biological markers for therapeutic targets as well as diagnostic and prognostic purposes. Targeting circRNAs and the gut microbiota for the treatment of gastrointestinal cancers is also being continued to study. Despite significant initiatives, the connection between circRNAs and the gut microbiota and the emergence of gastrointestinal cancers remains poorly understood. In this study, we will go over the most recent studies to emphasize the key roles of circRNAs and gut microbiota in gastrointestinal cancer progression and therapeutic options. In order to create effective therapies and plan for the future gastrointestinal therapy, it is important to comprehend the functions and mechanisms of circRNAs and the gut microbiota.

Involvement of the Gut Microbiome in the Local and Systemic Immune Response to Pancreatic Ductal Adenocarcinoma

The systemic and local immunosuppression exhibited by pancreatic ductal adenocarcinoma (PDAC) contributes significantly to its aggressive nature. There is a need for a greater understanding of the mechanisms behind this profound immune evasion, which makes it one of the most challenging malignancies to treat and thus one of the leading causes of cancer death worldwide. The gut microbiome is now thought to be the largest immune organ in the body and has been shown to play an important role in multiple immune-mediated diseases. By summarizing the current literature, this review examines the mechanisms by which the gut microbiome may modulate the immune response to PDAC. Evidence suggests that the gut microbiome can alter immune cell populations both in the peripheral blood and within the tumour itself in PDAC patients. In addition, evidence suggests that the gut microbiome influences the composition of the PDAC tumour microbiome, which exerts a local effect on PDAC tumour immune infiltration. Put together, this promotes the gut microbiome as a promising route for future therapies to improve immune responses in PDAC patients.

Forces at play: exploring factors affecting the cancer metastasis

Metastatic disease, a leading and lethal indication of deaths associated with tumors, results from the dissemination of metastatic tumor cells from the site of primary origin to a distant organ. Dispersion of metastatic cells during the development of tumors at distant organs leads to failure to comply with conventional treatments, ultimately instigating abrupt tissue homeostasis and organ failure. Increasing evidence indicates that the tumor microenvironment (TME) is a crucial factor in cancer progression and the process of metastatic tumor development at secondary sites. TME comprises several factors contributing to the initiation and progression of the metastatic cascade. Among these, various cell types in TME, such as mesenchymal stem cells (MSCs), lymphatic endothelial cells (LECs), cancer-associated fibroblasts (CAFs), myeloid-derived suppressor cells (MDSCs), T cells, and tumor-associated macrophages (TAMs), are significant players participating in cancer metastasis. Besides, various other factors, such as extracellular matrix (ECM), gut microbiota, circadian rhythm, and hypoxia, also shape the TME and impact the metastatic cascade. A thorough understanding of the functions of TME components in tumor progression and metastasis is necessary to discover new therapeutic strategies targeting the metastatic tumor cells and TME. Therefore, we reviewed these pivotal TME components and highlighted the background knowledge on how these cell types and disrupted components of TME influence the metastatic cascade and establish the premetastatic niche. This review will help researchers identify these altered components' molecular patterns and design an optimized, targeted therapy to treat solid tumors and restrict metastatic cascade.

Ginsenoside Rk3 modulates gut microbiota and regulates immune response of group 3 innate lymphoid cells to against colorectal tumorigenesis

The gut microbiota plays a pivotal role in the immunomodulatory and protumorigenic microenvironment of colorectal cancer (CRC). However, the effect of ginsenoside Rk3 (Rk3) on CRC and gut microbiota remains unclear. Therefore, the purpose of this study is to explore the potential effect of Rk3 on CRC from the perspective of gut microbiota and immune regulation. Our results reveal that treatment with Rk3 significantly suppresses the formation of colon tumors, repairs intestinal barrier damage, and regulates the gut microbiota imbalance caused by CRC, including enrichment of probiotics such as Akkermansia muciniphila and Barnesiella intestinihominis, and clearance of pathogenic Desulfovibrio. Subsequent metabolomics data demonstrate that Rk3 can modulate the metabolism of amino acids and bile acids, particularly by upregulating glutamine, which has the potential to regulate the immune response. Furthermore, we elucidate the regulatory effects of Rk3 on chemokines and inflammatory factors associated with group 3 innate lymphoid cells (ILC3s) and T helper 17 (Th17) signaling pathways, which inhibits the hyperactivation of the Janus kinase-signal transducer and activator of transcription 3 (JAK-STAT3) signaling pathway. These results indicate that Rk3 modulates gut microbiota, regulates ILC3s immune response, and inhibits the JAK-STAT3 signaling pathway to suppress the development of colon tumors. More importantly, the results of fecal microbiota transplantation suggest that the inhibitory effect of Rk3 on colon tumors and its regulation of ILC3 immune responses are mediated by the gut microbiota. In summary, these findings emphasize that Rk3 can be utilized as a regulator of the gut microbiota for the prevention and treatment of CRC.

TTD: Therapeutic Target Database describing target druggability information

Target discovery is one of the essential steps in modern drug development, and the identification of promising targets is fundamental for developing first-in-class drug. A variety of methods have emerged for target assessment based on druggability analysis, which refers to the likelihood of a target being effectively modulated by drug-like agents. In the therapeutic target database (TTD), nine categories of established druggability characteristics were thus collected for 426 successful, 1014 clinical trial, 212 preclinical/patented, and 1479 literature-reported targets via systematic review. These characteristic categories were classified into three distinct perspectives: molecular interaction/regulation, human system profile and cell-based expression variation. With the rapid progression of technology and concerted effort in drug discovery, TTD and other databases were highly expected to facilitate the explorations of druggability characteristics for the discovery and validation of innovative drug target. TTD is now freely accessible at: https://idrblab.org/ttd/.

Targeting gut microbial nitrogen recycling and cellular uptake of ammonium to improve bortezomib resistance in multiple myeloma

The gut microbiome has been found to play a crucial role in the treatment of multiple myeloma (MM), which is still considered incurable due to drug resistance. In previous studies, we demonstrated that intestinal nitrogen-recycling bacteria are enriched in patients with MM. However, their role in MM relapse remains unclear. This study highlights the specific enrichment of Citrobacter freundii (C. freundii) in patients with relapsed MM. Through fecal microbial transplantation experiments, we demonstrate that C. freundii plays a critical role in inducing drug resistance in MM by increasing levels of circulating ammonium. The ammonium enters MM cells through the transmembrane channel protein SLC12A2, promoting chromosomal instability and drug resistance by stabilizing the NEK2 protein. We show that furosemide sodium, a loop diuretic, downregulates SLC12A2, thereby inhibiting ammonium uptake by MM cells and improving progression-free survival and curative effect scores. These findings provide new therapeutic targets and strategies for the intervention of MM progression and drug resistance.

Roles of microbiota in pancreatic cancer development and treatment

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease with poor prognosis. This is due to the fact that most cases are only diagnosed at an advanced and palliative disease stage, and there is a high incidence of therapy resistance. Despite ongoing efforts, to date, the mechanisms underlying PDAC oncogenesis and its poor responses to treatment are still largely unclear. As the study of the microbiome in cancer progresses, growing evidence suggests that bacteria or fungi might be key players both in PDAC oncogenesis as well as in its resistance to chemo- and immunotherapy, for instance through modulation of the tumor microenvironment and reshaping of the host immune response. Here, we review how the microbiota exerts these effects directly or indirectly via microbial-derived metabolites. Finally, we further discuss the potential of modulating the microbiota composition as a therapy in PDAC.

Pharmacomicrobiomics-Guided Precision Oncology: A New Frontier of P4 (Predictive, Personalized, Preventive, and Participatory) Medicine and Microbiome-Based Therapeutics

Pharmacomicrobiomics is a rapidly developing field that promises to make significant contributions to predictive, personalized, preventive, and participatory (P4) medicine. This is becoming evident particularly in the field of precision (P4) oncology by taking seriously the crucial role microbiome plays in health and disease. Several studies have already shown that clinicians can harness insights from the microbiome to better predict treatment response, reduce side effects, and improve overall outcomes for cancer patients. Furthermore, pharmacomicrobiomics will undoubtedly play a crucial role in shaping the future of cancer treatment in the era of P4 oncology as we continue to unravel the intricate relationships between the microbiome and cancer. This perspective and innovation analysis discusses the emerging intersection of P4 medicine and P4 oncology, as seen through a lens of pharmacomicrobiomics. A key promise of pharmacomicrobiomics is the development of personalized microbiome-based therapeutics. In all, we suggest that optimizing cancer treatment and prevention by harnessing pharmacomicrobiomics has vast potentials for precision oncology, and personalized medicine using the right drug, at the right dose, for the right patient, and at the right time.

Lactobacillus plantarum modulate gut microbiota and intestinal immunity in cyclophosphamide-treated mice model

Gut microbiota (GM) contributes to the production of immune-regulatory molecules and cytokines. However, our understanding regarding intricate relationship between Lactobacillus plantarum and GM on regulation of immune function remained limited. To investigate the effect of Lactobacillus plantarum on an immunosuppressed mouse model, we employed cyclophosphamide treatment and conducted various analysis including H&E (hematoxylin-eosin staining), immunohistochemistry, 16S rRNA gene sequencing, and RT-PCR. Our results demonstrated that the administration of Lactobacillus plantarum had significant immunoenhancing effects in the immune-suppressed mice, as evidenced by the restoration of functional expression of specific immune markers in the spleen and an increase in the number of goblet cells in intestine (P < 0.05). Microbial taxonomic analysis revealed alterations in the gut microbiota composition, characterized by a decrease in the richness of Firmicutes and an increase in the proportion of Verrucomicrobia and Actinobacteria following cyclophosphamide treatment. Furthermore, cyclophosphamide treatment significantly suppressed the mRNA expression of inflammatory cytokines (P < 0.05), which were subsequently restored after administration of Lactobacillus plantarum. These observations provide valuable insights into the complex interplay between probiotics, gut microbiota, and immune system functioning.

Mechanism-guided fine-tuned microbiome potentiates anti-tumor immunity in HCC

Microbiome, including bacteria, fungi, and viruses, plays a crucial role in shaping distal and proximal anti-tumor immunity. Mounting evidence showed that commensal microbiome critically modulates immunophenotyping of hepatocellular carcinoma (HCC), a leading cause of cancer-related death. However, their role in anti-tumor surveillance of HCC is still poorly understood. Herein, we spotlighted growing interests in how the microbiome influences the progression and immunotherapeutic responses of HCC via changing local tumor microenvironment (TME) upon translocating to the sites of HCC through different "cell-type niches". Moreover, we summarized not only the associations but also the deep insight into the mechanisms of how the extrinsic microbiomes interplay with hosts to shape immune surveillance and regulate TME and immunotherapeutic responses. Collectively, we provided a rationale for a mechanism-guided fine-tuned microbiome to be neoadjuvant immunotherapy in the near future.

Immunomodulatory functions of microorganisms in tissue regenerative healing

External pathogenic microorganisms and commensal microorganisms in the body have either harmful or beneficial impacts on the regenerative repair of tissues, and the immune system plays a crucial regulatory role in this process. This review summarises our current understanding of microorganism-immune system interactions, with a focus on how these interactions impact the renewal and repair ability of tissues, including skin, bone, gut, liver, and nerves. This review concludes with a discussion of the mechanisms by which microbes act on various types of immune cells to affect tissue regeneration, offers potential strategies for using microbial therapies to enhance the regenerative repair function of tissues, and suggest novel therapeutic approaches for regenerative medicine. STATEMENT OF SIGNIFICANCE: Microbiological communities have crucial impacts on human health and illness by participating in energy collection and storage and performing various metabolic processes. External pathogenic microorganisms and commensal microorganisms in the body have either harmful or beneficial impacts on the regenerative repair of tissues, and the immune system plays a critical regulatory role in this process. This study reviews the important correlation between microorganisms and the immune system and investigates the mechanism of various microorganism that participate in the regeneration and repair of tissues and organs by modulating immune system.

Methylglyoxal from gut microbes boosts radiosensitivity and radioimmunotherapy in rectal cancer by triggering endoplasmic reticulum stress and cGAS-STING activation

BACKGROUND

Preoperative radiation therapy (preRT) is a fundamental aspect of neoadjuvant treatment for rectal cancer (RC), but the response to this treatment remains unsatisfactory. The combination of radiation therapy (RT) and immunotherapy (iRT) presents a promising approach to cancer treatment, though the underlying mechanisms are not yet fully understood. The gut microbiota may influence the response to RT and immunotherapy. Therefore, we aimed to identify the metabolism of gut microbiota to reverse radioresistance and enhance the efficacy of iRT.

METHODS

Fecal and serum samples were prospectively collected from patients with locally advanced rectal cancer (LARC) who had undergone pre-RT treatment. Candidate gut microbiome-derived metabolites linked with radiosensitization were screened using 16s rRNA gene sequencing and ultrahigh-performance liquid chromatography-mass coupled with mass spectrometry. In vitro and in vivo studies were conducted to assess the radiosensitizing effects of the metabolites including the syngeneic CT26 tumor model and HCT116 xenograft tumor model, transcriptomics and immunofluorescence. The CT26 abscopal effect modeling was employed to evaluate the combined effects of metabolites on iRT.

RESULTS

We initially discovered the gut microbiota-associated metabolite, methylglyoxal (MG), which accurately predicts the response to preRT (Area Under Curve (AUC) value of 0.856) among patients with LARC. Subsequently, we observed that MG amplifies the RT response in RC by stimulating intracellular reactive oxygen species (ROS) and reducing hypoxia in the tumor in vitro and in vivo. Additionally, our study demonstrated that MG amplifies the RT-induced activation of the cyclic guanosine monophosphate AMP synthase-stimulator of interferon genes pathway by elevating DNA double-strand breaks. Moreover, it facilitates immunogenic cell death generated by ROS-mediated endoplasmic reticulum stress, consequently leading to an increase in CD8+ T and natural killer cells infiltrated in the tumor immune microenvironment. Lastly, we discovered that the combination of anti-programmed cell death protein 1 (anti-PD1) therapy produced long-lasting complete responses in all irradiated tumor sites and half of the non-irradiated ones.

CONCLUSIONS

Our research indicates that MG shows promise as a radiosensitizer and immunomodulator for RC. Furthermore, we propose that combining MG with iRT has great potential for clinical practice.

Diet-driven microbiome changes and physical activity in cancer patients

Exploring the role of the gut microbiome in oncology is gaining more attention, mainly due to its ability to shape the immune system in cancer patients. A well-balanced microbial composition forms a symbiotic relationship with the host organism. Mounting evidence supports the potential of modifiable lifestyle factors, such as diet and physical activity, in restoring intestinal dysbiosis related to cancer development and treatment. In this Minireview, we describe the host-microbiome interplay following different dietary patterns, including a high-fat diet, fiber-rich diet, diet rich in rice and beans, Mediterranean diet, ketogenic diet, and physical activity in preclinical findings and clinical settings. According to the results, nutrition is a critical factor influencing the composition of gut microbial communities. Therefore, knowledge about the patient's nutritional status in pre-treatment and treatment becomes crucial for further management. A combination of individualized dietary habits and professional training plans might help to maintain gut homeostasis, potentially improving the response to anti-cancer therapy and the quality of life in cancer survivors. However, a deep understanding of underlying mechanisms and large clinical trials are needed to uncover clinically relevant correlations for personalized treatment approaches leading to better outcomes for cancer patients.

Serum, spleen metabolomics and gut microbiota reveals effect of catalpol on blood deficiency syndrome caused by cyclophosphamide and acetylphenylhydrazine

Catalpol (CA), extracted from Rehmannia Radix, holds extensive promise as a natural medicinal compound. This study employed 16S rRNA gene sequencing and combined serum and spleen metabolomics to profoundly investigate the therapeutic effects of CA on blood deficiency syndrome (BDS) and the underlying mechanisms. Notably, CA exhibited effectiveness against BDS induced by cyclophosphamide (CP) and acetylphenylhydrazine (APH) in rats-CA substantially elevated levels of crucial indicators such as erythropoietin (EPO), granulocyte colony-stimulating factor (G-CSF), tumor necrosis factor-alpha (TNF-a), and interleukin-6 (IL-6). Additionally, CA could alleviate peripheral blood cytopenia. Furthermore, the analysis of 16S rRNA revealed that CA had the potential to reverse the Firmicutes/Bacteroidetes (F/B) ratio associated with BDS. Through comprehensive serum and spleen metabolomic profiling, we successfully identified 22 significant biomarkers in the serum and 23 in the spleen, respectively. Enrichment analysis underscored Glycerophospholipid metabolism and Sphingolipid metabolism as potential pathways through which CA exerts its therapeutic effects on BDS.

Diversification and deleterious role of microbiome in gastric cancer

Gut microbiota dictates the fate of several diseases, including cancer. Most gastric cancers (GC) belong to gastric adenocarcinomas (GAC). Helicobacter pylori colonizes the gastric epithelium and is the causative agent of 75% of all stomach malignancies globally. This bacterium has several virulence factors, including cytotoxin-associated gene A (CagA), vacuolating cytotoxin (VacA), and outer membrane proteins (OMPs), all of which have been linked to the development of gastric cancer. In addition, bacteria such as Escherichia coli, Streptococcus, Clostridium, Haemophilus, Veillonella, Staphylococcus, and Lactobacillus play an important role in the development of gastric cancer. Besides, lactic acid bacteria (LAB) such as Bifidobacterium, Lactobacillus, Lactococcus, and Streptococcus were found in greater abundance in GAC patients. To identify potential diagnostic and therapeutic interventions for GC, it is essential to understand the mechanistic role of H. pylori and other bacteria that contribute to gastric carcinogenesis. Furthermore, understanding bacteria-host interactions and bacteria-induced inflammatory pathways in the host is critical for developing treatment targets for gastric cancer.

Modulating the gut microbiota by probiotics, prebiotics, postbiotics, and fecal microbiota transplantation: An emerging trend in cancer patient care

Treatment resistance, together with acute and late adverse effects, represents critical issues in the management of cancer patients. Promising results from preclinical and clinical research underline the emerging trend of a microbiome-based approach in oncology. Favorable bacterial species and higher gut diversity are associated with increased treatment efficacy, mainly in chemo- and immunotherapy. On the other hand, alterations in the composition and activity of gut microbial communities are linked to intestinal dysbiosis and contribute to high treatment-induced toxicity. In this Review, we provide an overview of studies concerning gut microbiota modulation in patients with solid and hematologic malignancies with a focus on probiotics, prebiotics, postbiotics, and fecal microbiota transplantation. Targeting the gut microbiome might bring clinical benefits and improve patient outcomes. However, a deeper understanding of mechanisms and large clinical trials concerning microbiome and immunological profiling is warranted to identify safe and effective ways to incorporate microbiota-based interventions in routine clinical practice.

Pancreatic Exocrine Insufficiency and the Gut Microbiome in Pancreatic Cancer: A Target for Future Diagnostic Tests and Therapies?

Pancreatic exocrine insufficiency (PEI) is common amongst pancreatic cancer patients and is associated with poorer treatment outcomes. Pancreatic enzyme replacement therapy (PERT) is known to improve outcomes in pancreatic cancer, but the mechanisms are not fully understood. The aim of this narrative literature review is to summarise the current evidence linking PEI with microbiome dysbiosis, assess how microbiome composition may be impacted by PERT treatment, and look towards possible future diagnostic and therapeutic targets in this area. Early evidence in the literature reveals that there are complex mechanisms by which pancreatic secretions modulate the gut microbiome, so when these are disturbed, as in PEI, gut microbiome dysbiosis occurs. PERT has been shown to return the gut microbiome towards normal, so called rebiosis, in animal studies. Gut microbiome dysbiosis has multiple downstream effects in pancreatic cancer such as modulation of the immune response and the response to chemotherapeutic agents. It therefore represents a possible future target for future therapies. In conclusion, it is likely that the gut microbiome of pancreatic cancer patients with PEI exhibits dysbiosis and that this may potentially be reversible with PERT. However, further human studies are required to determine if this is indeed the case.

Impact of Helicobacter pylori infection status on outcomes among patients with advanced gastric cancer treated with immune checkpoint inhibitors

BACKGROUND

Gut microbiota composition can influence cancer immunotherapy response. Recent evidence suggests Helicobacter pylori infection may reduce immune checkpoint inhibitor (ICI) efficacy in lung cancer and melanoma, but thorough characterization of this association in patients with gastric cancer is lacking. We aimed to determine the impact of H. pylori on survival in this population.

METHODS

This single-center, retrospective study included all ICI-treated individuals with metastatic gastric cancer and documented H. pylori status at Memorial Sloan Kettering between July 2013 and October 2021. H. pylori-positive status was defined as history of infection obtained via breath test, stool antigen test, histopathology, and/or chart documentation. Negative status was defined as explicitly negative testing, histopathology, and/or chart documentation. Primary outcomes were progression-free survival (PFS) and overall survival (OS).

RESULTS

Of 215 included patients, 49 had documented history of H. pylori infection. Compared with H. pylori-negative patients, positive individuals tended to be younger, non-white, and Hispanic with non-cardia and intestinal-type gastric cancer. H. pylori-positive patients had significantly shorter median PFS (3.2 vs 6.8 months, HR 1.96, p<0.01) and OS (9.8 vs 17.9 months, HR 1.54, p=0.02). Multivariable analysis confirmed H. pylori infection as an independent predictor of PFS (HR 3.04, p<0.01) and OS (HR 2.24, p=0.01).

CONCLUSIONS

In this largest study of its kind, H. pylori infection was associated with inferior survival in ICI-treated patients with gastric cancer. This suggests H. pylori status may be a prognostic marker of immune responsiveness. Future studies are needed to elucidate immunoregulatory mechanisms and whether treatment of active infections would improve immunotherapy outcomes.

The Evolving Landscape of Fecal Microbial Transplantation

The human gastrointestinal tract houses an enormous microbial ecosystem. Recent studies have shown that the gut microbiota plays significant physiological roles and maintains immune homeostasis in the human body. Dysbiosis, an imbalanced gut microbiome, can be associated with various disease states, as observed in infectious diseases, inflammatory diseases, autoimmune diseases, and cancer. Modulation of the gut microbiome has become a therapeutic target in treating these disorders. Fecal microbiota transplantation (FMT) from a healthy donor restores the normal gut microbiota homeostasis in the diseased host. Ample evidence has demonstrated the efficacy of FMT in recurrent Clostridioides difficile infection (rCDI). The application of FMT in other human diseases is gaining attention. This review aims to increase our understanding of the mechanisms of FMT and its efficacies in human diseases. We discuss the application, route of administration, limitations, safety, efficacies, and suggested mechanisms of FMT in rCDI, autoimmune diseases, and cancer. Finally, we address the future perspectives of FMT in human medicine.

Nano-enabled colorectal cancer therapy

Colorectal cancer (CRC), one of the most common and deadliest diseases worldwide, poses a great health threat and social burden. The clinical treatments of CRC encompassing surgery, chemotherapy, and radiotherapy are challenged with toxicity, therapy resistance, and recurrence. In the past two decades, targeted therapy and immunotherapy have greatly improved the therapeutic benefits of CRC patients but they still suffer from drug resistance and low response rates. Very recently, gut microbiota regulation has exhibited a great potential in preventing and treating CRC, as well as in modulating the efficacy and toxicity of chemotherapy and immunotherapy. In this review, we provide a cutting-edge summary of nanomedicine-based treatment in colorectal cancer, highlighting the recent progress of oral and systemic tumor-targeting and/or tumor-activatable drug delivery systems as well as novel therapeutic strategies against CRC, including nano-sensitizing immunotherapy, anti-inflammation, gut microbiota modulation therapy, etc. Finally, the recent endeavors to address therapy resistance, metastasis, and recurrence in CRC were discussed. We hope this review could offer insight into the design and development of nanomedicines for CRC and beyond.

Role of gut microbiome in cancer immunotherapy: from predictive biomarker to therapeutic target

Immunotherapy has emerged as an effective treatment for various types of cancers. Recent studies have highlighted a significant correlation between the gut microbiome and patients' response to immunotherapy. Several characteristics of the gut microbiome, such as community structures, taxonomic compositions, and molecular functions, have been identified as crucial biomarkers for predicting immunotherapy response and immune-related adverse events (irAEs). Unlike other -omics, the gut microbiome can serve as not only biomarkers but also potential targets for enhancing the efficacy of immunotherapy. Approaches for modulating the gut microbiome include probiotics/prebiotics supplementation, dietary interventions, fecal microbiota transplantation (FMT), and antibiotic administration. This review primarily focuses on elucidating the potential role of the gut microbiome in predicting the response to cancer immunotherapy and improving its efficacy. Notably, we explore reasons behind inconsistent findings observed in different studies, and highlight the underlying benefits of antibiotics in liver cancer immunotherapy.

The gut microbiome changes in wild type and IL-18 knockout mice after 9.0 Gy total body irradiation

BACKGROUND

Recent studies have shown that gut microbiome plays important roles in response to radiation exposure. IL-18, an inflammatory cytokine, is highly elevated in mice, mini-pigs and nonhuman primates after radiation exposure. Blocking IL-18 using its endogenous binding protein (IL-18BP) increases mice survival after radiation exposure by decreasing bone marrow interferon-gamma levels.

METHODS

To further characterize the roles of IL-18 in response to radiation, both wild type and IL-18 knockout (IL-18 KO) mice were exposed to 9.0 Gy total body irradiation (TBI). The 30-day survival result demonstrated that IL-18 KO mice were significantly more resistant to radiation compared to the wild type mice (p < 0.0001). Mouse faecal samples were collected at pre-radiation (d0), d1, d3, d7, d14, d21 and d29 after radiation exposure. Microbiome profiling was performed on the faecal samples using 16S and ITS sequencing technology.

RESULTS

Data analysis showed that there was significant difference in the bacterial microbiome between wild type and IL-18 KO mice. Cohousing of wild type and IL-18 KO mice decreased the bacterial microbiome difference between the two genotypes. Much fewer bacterial genera were significantly changed in wild type mice than the IL-18 KO mice after radiation exposure. The different composition of the IL-18 KO mice and wild type mice persisted even after radiation exposure. Bacterial genera that significantly correlated with other genera were identified in the IL-18 KO and wild type mice. The metabolic pathways that differentially expressed in both genotypes were identified. The animal bacterial microbiome data could be used to predict the animal's radiation status. The fungal microbiome had no significant difference regarding genotype or time after radiation exposure.

CONCLUSION

The current study helps understand the gut microbiome in different genetic backgrounds and its temporal changes after radiation exposure. Our data provide insight into the mechanisms underlying radiation-induced toxicity and help identify bacteria important in response to radiation.

Anticancer Potential of the Plant-Derived Saponin Gracillin: A Comprehensive Review of Mechanistic Approaches

With the increasing prevalence of cancer and the toxic side effects of synthetic drugs, natural products are being developed as promising therapeutic approaches. Gracillin is a naturally occurring triterpenoid steroidal saponin with several therapeutic activities. It is obtained as a major compound from different Dioscorea species. This review was designated to summarize the research progress on the anti-cancer activities of gracillin focusing on the underlying cellular and molecular mechanisms, as well as its pharmacokinetic features. The data were collected (up to date as of May 1, 2023) from various reliable and authentic literatures comprising PubMed, Springer Link, Scopus, Wiley Online, Web of Science, ScienceDirect, and Google Scholar. The findings demonstrated that gracillin displays promising anticancer effects through various molecular mechanisms, including anti-inflammatory effects, apoptotic cell death, induction of oxidative stress, cytotoxicity, induction of genotoxicity, cell cycle arrest, anti-proliferative effect, autophagy, inhibition of glycolysis, and blocking of cancer cell migration. Additionally, this review highlighted the pharmacokinetic features of gracillin, indicating its lower oral bioavailability. As a conclusion, it can be proposed that gracillin could serve as a hopeful chemotherapeutic agent. However, further extensive clinical research is recommended to establish its safety, efficacy, and therapeutic potential in cancer treatment.

Gastrointestinal Dysfunction in Neurological and Neurodegenerative Disorders

Increasing research links the gut microbiome to neurodegenerative disorders. The gut microbiome communicates with the central nervous system via the gut-brain axis and affects behavioral and cognitive phenotypes. Dysbiosis (a dysfunctional microbiome) drives increased intestinal permeability and inflammation that can negatively affect the brain via the gut-brain axis. Healthier metabolic and lipid profiles and cognitive phenotypes are observed in individuals with more distinct microbiomes. In this review, we discuss the role of the gut microbiome and gut-brain axis in neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease and related animal models, in cancer and cancer treatments, and in metabolic syndrome. We also discuss strategies to improve the gut microbiome and ultimately brain function. Because healthier cognitive phenotypes are observed in individuals with more distinct microbiomes, increased efforts are warranted to develop therapeutic strategies for those at increased risk of developing neurological disorders and patients diagnosed with those disorders.

Probiotic-Derived Bioactive Compounds in Colorectal Cancer Treatment

Colorectal cancer (CRC) is a multifactorial disease with increased morbidity and mortality rates globally. Despite advanced chemotherapeutic approaches for the treatment of CRC, low survival rates due to the regular occurrence of drug resistance and deleterious side effects render the need for alternative anticancer agents imperative. Accumulating evidence supports that gut microbiota imbalance precedes the establishment of carcinogenesis, subsequently contributing to cancer progression and response to anticancer therapy. Manipulation of the gut microbiota composition via the administration of probiotic-derived bioactive compounds has gradually attained the interest of scientific communities as a novel therapeutic strategy for CRC. These compounds encompass miscellaneous metabolic secreted products of probiotics, including bacteriocins, short-chain fatty acids (SCFAs), lactate, exopolysaccharides (EPSs), biosurfactants, and bacterial peptides, with profound anti-inflammatory and antiproliferative properties. This review provides a classification of postbiotic types and a comprehensive summary of the current state of research on their biological role against CRC. It also describes how their intricate interaction with the gut microbiota regulates the proper function of the intestinal barrier, thus eliminating gut dysbiosis and CRC development. Finally, it discusses the future perspectives in precision-medicine approaches as well as the challenges of their synthesis and optimization of administration in clinical studies.

The Interplay between Medical Plants and Gut Microbiota in Cancer

The gut microbiota is a dynamic community of bacteria distributed in the gastroenteric tract and changes in response to diseases, diet, use of antibiotics and probiotics, hygiene status, and other environmental factors. Dysbiosis, a disruption of the normal crosstalk between the host and the microbes, is associated with obesity, diabetes, cancer, and cardiovascular diseases, is linked to a reduction of anti-inflammatory bacteria like Lactobacillus and Roseburia, and to an increase in the growth of proinflammatory species like Ruminococcus gnavus and Bacteroidetes. Some plants possess anticancer properties and various studies have reported that some of these are also able to modulate the gut microbiota. The aim of this work is to evaluate the crucial relationship between medical plants and gut microbiota and the consequences on the onset and progression of cancer. In vivo studies about hematological malignancies showed that beta-glucans tie to endogenous antibeta glucan antibodies and to iC3b, an opsonic fragment of the central complement protein C3, leading to phagocytosis of antibody-targeted neoplastic cells and potentiation of the cytotoxic activity of the innate immune system if administered together with monoclonal antibodies. In conclusion, this review suggests the potential use of medical plants to improve gut dysbiosis and assist in the treatment of cancer.