Lactobacillus casei combined with Lactobacillus reuteri alleviate pancreatic cancer by inhibiting TLR4 to promote macrophage M1 polarization and regulate gut microbial homeostasis

Upregulation of Lactobacillus spp. in gut microbiota as a novel mechanism for environmental eustress-induced anti-pancreatic cancer effects

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy with limited effective treatment options. Emerging evidence links enriched environment (EE)-induced eustress to PDAC inhibition. However, the underlying mechanisms remain unclear. In this study, we explored the role of gut microbiota in PDAC-suppressive effects of EE. We demonstrated that depletion of gut microbiota with antibiotics abolished EE-induced tumor suppression, while fecal microbiota transplantation (FMT) from EE mice significantly inhibited tumor growth in both subcutaneous and orthotopic PDAC models housed in standard environment. 16S rRNA sequencing revealed that EE enhanced gut microbiota diversity and selectively enriched probiotic Lactobacillus, particularly L. reuteri. Treatment with L. reuteri significantly suppressed PDAC tumor growth and increased natural killer (NK) cell infiltration into the tumor microenvironment. Depletion of NK cells alleviated the anti-tumor effects of L. reuteri, underscoring the essential role of NK cell-mediated immunity in anti-tumor response. Clinical analysis of PDAC patients showed that higher fecal Lactobacillus abundance correlated with improved progression-free and overall survival, further supporting the therapeutic potential of L. reuteri in PDAC. Overall, this study identifies gut microbiota as a systemic regulator of PDAC under psychological stress. Supplementation of psychobiotic Lactobacillus may offer a novel therapeutic strategy for PDAC.

The relationship of the microbiome, associated metabolites and the gut barrier with pancreatic cancer

Pancreatic cancers have high mortality and rising incidence rates which may be related to unhealthy western-type dietary and lifestyle patterns as well as increasing body weights and obesity rates. Recent data also suggest a role for the gut microbiome in the development of pancreatic cancer. Here, we review the experimental and observational evidence for the roles of the oral, gut and intratumoural microbiomes, impaired gut barrier function and exposure to inflammatory compounds as well as metabolic dysfunction as contributors to pancreatic disease with a focus on pancreatic ductal adenocarcinoma (PDAC) initiation and progression. We also highlight some emerging gut microbiome editing techniques currently being investigated in the context of pancreatic disease. Notably, while the gut microbiome is significantly altered in PDAC and its precursor diseases, its utility as a diagnostic and prognostic tool is hindered by a lack of reproducibility and the potential for reverse causality in case-control cohorts. Future research should emphasise longitudinal and mechanistic studies as well as integrating lifestyle exposure and multi-omics data to unravel complex host-microbiome interactions. This will allow for deeper aetiologic and mechanistic insights that can inform treatments and guide public health recommendations.

Unveiling the microbial influence: bacteria's dual role in tumor metastasis

As cancer research advances, the intricate relationship between the microbiome and cancer is gaining heightened recognition, especially concerning tumor metastasis, where bacterial involvement becomes increasingly complex. This review seeks to systematically examine the dual roles of bacteria in the tumor metastasis process, encompassing both mechanisms that facilitate metastasis and the inhibitory effects exerted by specific microorganisms. We explore the mechanisms through which bacteria influence tumor cell migration by inducing chronic inflammation, evading host immune responses, and remodeling the ECM. Moreover, the immunomodulatory potential of probiotics and genetically engineered bacteria offers promising prospects for the prevention and treatment of tumor metastasis. This article elucidates the complexity and emerging frontiers of bacterial involvement in tumor metastasis by examining the clinical significance of bacteria as potential biomarkers and evaluating the effects of antibiotic usage on the metastatic process. We posit that comprehending the biological characteristics and clinical significance of bacteria, as a critical component of the tumor microenvironment, will offer innovative strategies and theoretical foundations for cancer treatment. Furthermore, this article explores future research directions, including the application of microbiome technologies and bacteria-based therapeutic strategies, thereby offering a valuable perspective for the development of novel anti-cancer approaches.

Anticancer activity of Weizmannia coagulans MZY531on H22 tumor-bearing mice by regulating inflammation, autophagy-dependent apoptosis, and gut microbiota

Increasing studies have shown that the efficacy of Weizmannia coagulans in treating various cancers. We recently identified W. coagulans MZY531 with potent cell anti-proliferation and exhibiting apoptosis induction activities against the mouse H22 hepatocellular carcinoma cell line.However, the anti-cancer effect of W. coagulans MZY531 against liver cancer in vivo has not been verified. The objective of this study was to assess the anti-hepatoma effect of W. coagulans MZY531 on H22 tumor-bearing mice and the underlying mechanism. The results demonstrated that W. coagulans MZY531 reduced the weight and size of the tumor in comparison to the model group. The levels of serum pro-inflammatory cytokines, including IL-1β, IL-6, IL-2 and TNF-α were suppressed by W. coagulans MZY531 administration. Immunofluorescence and TUNEL analyses demonstrated that W. coagulans MZY531 significantly increased the number of cleaved caspase-3 cells and induced apoptosis in tumor tissues. Importantly, W. coagulans MZY531 activated the AMPK/mTOR autophagy-dependent apoptosis pathway, and regulated the TLR4/MyD88/TRAF-6/NF-κB and JAK2/STAT3 inflammatory signaling pathways through mechanisms. Additionally, Fecal analysis demonstrated the capacity of W. coagulans MZY531 to remodel the gut microbiota of hepatocellular carcinoma-infected mice. Collectively, this experimental finding suggested that W. coagulans MZY531 exhibited prominent anticancer activities in vivo at least partly via reducing inflammation, inducing autophagy-dependent apoptosis, and regulating gut microbiota in H22 tumor-bearing mice.

Inflammation, microbiota, and pancreatic cancer

Pancreatic cancer (PC) is a malignancy of gastrointestinal tract threatening the life of people around the world. In spite of the advances in the treatment of PC, the overall survival of this disease in advanced stage is less than 12%. Moreover, PC cells have aggressive behaviour in proliferation and metastasis as well as capable of developing therapy resistance. Therefore, highlighting the underlying molecular mechanisms in PC pathogenesis can provide new insights for its treatment. In the present review, inflammation and related pathways as well as role of gut microbiome in the regulation of PC pathogenesis are highlighted. The various kinds of interleukins and chemokines are able to regulate angiogenesis, metastasis, proliferation, inflammation and therapy resistance in PC cells. Furthermore, a number of molecular pathways including NF-κB, TLRs and TGF-β demonstrate dysregulation in PC aggravating inflammation and tumorigenesis. Therapeutic regulation of these pathways can reverse inflammation and progression of PC. Both chronic and acute pancreatitis have been shown to be risk factors in the development of PC, further highlighting the role of inflammation. Finally, the composition of gut microbiota can be a risk factor for PC development through affecting pathways such as NF-κB to mediate inflammation.

Bacterial-Mediated In Situ Engineering of Tumour-Associated Macrophages for Cancer Immunotherapy

BACKGROUND/OBJECTIVES

Tumour-associated macrophages (TAMs) are critical components of the tumour microenvironment (TME), significantly influencing cancer progression and treatment resistance. This review aims to explore the innovative use of engineered bacteria to reprogram TAMs, enhancing their anti-tumour functions and improving therapeutic outcomes.

METHODS

We conducted a systematic review following a predefined protocol. Multiple databases were searched to identify relevant studies on TAMs, their phenotypic plasticity, and the use of engineered bacteria for reprogramming. Inclusion and exclusion criteria were applied to select studies, and data were extracted using standardised forms. Data synthesis was performed to summarise the findings, focusing on the mechanisms and therapeutic benefits of using non-pathogenic bacteria to modify TAMs.

RESULTS

The review summarises the findings that engineered bacteria can selectively target TAMs, promoting a shift from the tumour-promoting M2 phenotype to the tumour-fighting M1 phenotype. This reprogramming enhances pro-inflammatory responses and anti-tumour activity within the TME. Evidence from various studies indicates significant tumour regression and improved immune responses following bacterial therapy.

CONCLUSIONS

Reprogramming TAMs using engineered bacteria presents a promising strategy for cancer therapy. This approach leverages the natural targeting abilities of bacteria to modify TAMs directly within the tumour, potentially improving patient outcomes and offering new insights into immune-based cancer treatments. Further research is needed to optimise these methods and assess their clinical applicability.

The gut microbiome modulate response to immunotherapy in cancer

Gut microbiota have been reported to play an important role in the occurrence and development of malignant tumors. Currently, clinical studies have identified specific gut microbiota and its metabolites associated with efficacy of immunotherapy in multiple types of cancers. Preclinical investigations have elucidated that gut microbiota modulate the antitumor immunity and affect the efficacy of cancer immunotherapy. Certain microbiota and its metabolites may favorably remodel the tumor microenvironment by engaging innate and/or adaptive immune cells. Understanding how the gut microbiome interacts with cancer immunotherapy opens new avenues for improving treatment strategies. Fecal microbial transplants, probiotics, dietary interventions, and other strategies targeting the microbiota have shown promise in preclinical studies to enhance the immunotherapy. Ongoing clinical trials are evaluating these approaches. This review presents the recent advancements in understanding the dynamic interplay among the host immunity, the microbiome, and cancer immunotherapy, as well as strategies for modulating the microbiome, with a view to translating into clinical applications.

Are Probiotics Beneficial or Harmful for Pancreatic Cancer Outcomes?

Pancreatic cancer is influenced by interactions between cancer cells and the tumor microenvironment (TME), including tumor-infiltrating lymphocytes (TILs). Specifically, CD8 + T cells impact prognosis by eliminating cancer cells. Recent studies have revealed that microbiomes are present in pancreatic tissues and may affect tumor growth and immune responses. Additionally, recent studies revealed that the abundance of Bacteroides, Lactobacillus, and Peptoniphilus are associated with poor pancreatic cancer prognosis. This study investigates the role of oral probiotics in influencing pancreatic cancer outcomes. We retrospectively reviewed patients aged ≥ 18 years with pathologically confirmed pancreatic cancer from Seoul National University Hospital between January 2011 and January 2023. We investigated progression-free survival and overall survival between the control group and the probiotics group. Among pancreatic cancer patients undergoing palliative chemotherapy without radiotherapy and resection, there was a significant difference in overall survival (OS) when comparing the control group to the probiotics group (median: 10 months (9-11) vs. 12 months (9-19), p = 0.026). Regardless of the type of probiotics, oral probiotics may have a positive impact, but further research is still needed to understand the underlying immunological mechanisms.

Influence of the gut microbiota on immune cell interactions and cancer treatment

The tumour microenvironment represents a novel frontier in oncological research. Over the past decade, accumulating evidence has underscored the importance of the tumour microenvironment (TME), including tumour cells, stromal cells, immune cells, and various secreted factors, which collectively influence tumour growth, invasion, and responses to therapeutic agents. Immune cells within the TME are now widely acknowledged to play pivotal roles in tumour development and treatment. While some perspectives have posited that immune cells within the TME facilitate tumour progression and confer resistance to therapeutic interventions, contrasting conclusions also exist. Affirmative and negative conclusions appear to be context dependent, and a unified consensus has yet to be reached. The burgeoning body of research on the relationship between the gut microbiota and tumours in recent years has led to a growing understanding. Most studies have indicated that specific components of the gut microbiota, such as unique bacterial communities or specific secretory factors, play diverse roles in regulating immune cells within the TME, thereby influencing the prognosis and outcomes of cancer treatments. A detailed understanding of these factors could provide novel insights into the TME and cancer therapy. In this study, we aimed to synthesise information on the interactions between the gut microbiota and immune cells within the TME, providing an in-depth exploration of the potential guiding implications for future cancer therapies.

Causal associations between constipation and pan-cancer: a bidirectional Mendelian randomization study

Objective

Observational studies have suggested a potential association between constipation and several cancers. However, the causal relationship between constipation and cancer remains unclear. The purpose of this study is to explore the potential causal relationship between constipation and pan-cancer using Mendelian Randomization (MR) methods.

Methods

We performed a bidirectional MR analysis using publicly available summary data from Genome-Wide Association Studies (GWAS) statistics. The Inverse Variance Weighted (IVW) method was used as the main analysis method. We also used four MR methods: MR-Egger, Weighted Median, MR-PRESSO and MR.RAPS. Simultaneously, MR-Egger regression, Cochran's Q test and MR-PRESSO Global test were used to estimate the pleiotropy and heterogeneity of SNPs. In addition, we performed "leave-one-out" analyses" to avoid bias caused by horizontal pleiotropy of individual SNPs.

Results

MR analysis revealed a potential causal association between constipation and the risk of colorectal cancer (CRC) [IVW (OR= 1.0021 (1.0003, 1.0039), P= 0.0234)], lung cancer (LC) [IVW (OR=1.0955 (1.0134, 1.1843), P=0.0218)], Oral cavity and pharyngeal cancer (OPC) [IVW (OR=1.4068 (1.0070, 1.9652), P=0.0454)], and Pancreatic cancer (PC) [IVW (OR=1.5580 (1.0659, 2.2773), P=0.0221)]. In addition, we explored causal relationships between constipation and 12 other types of cancers, including gastric cancer, esophageal cancer, skin melanoma and so on. All five methods yielded no evidence of a causal association between constipation and the risk of these cancer types. In the reverse MR analysis, there was no evidence of a causal association between cancer and the risk of constipation for all five methods.

Conclusion

Our bidirectional MR study suggests a potential relationship between constipation and an increased risk of CRC, LC OPC and PC. The underlying mechanisms behind these associations will need to be explored in future experimental studies.

Unraveling the gut microbiome's contribution to pancreatic ductal adenocarcinoma: mechanistic insights and therapeutic perspectives

The gut microbiome plays a significant role in the pathogenesis of pancreatic ductal adenocarcinoma (PDAC), influencing oncogenesis, immune responses, and treatment outcomes. Studies have identified microbial species like Porphyromonas gingivalis and Fusobacterium nucleatum, that promote PDAC progression through various mechanisms. Additionally, the gut microbiome affects immune cell activation and response to immunotherapy, including immune checkpoint inhibitors and CAR-T therapy. Specific microbes and their metabolites play a significant role in the effectiveness of immune checkpoint inhibitors (ICIs). Alterations in the gut microbiome can either enhance or diminish responses to PD-1/PD-L1 and CTLA-4 blockade therapy. Additionally, bacterial metabolites like trimethylamine N-oxide (TMAO) and lipopolysaccharide (LPS) impact antitumor immunity, offering potential targets to augment immunotherapy responses. Modulating the microbiome through fecal microbiota transplantation, probiotics, prebiotics, dietary changes, and antibiotics shows promise in PDAC treatment, although outcomes are highly variable. Dietary modifications, particularly high-fiber diets and specific fat consumption, influence microbiome composition and impact cancer risk. Combining microbiome-based therapies with existing treatments holds potential for improving PDAC therapy outcomes, but further research is needed to optimize their effectiveness.

Current research progress, opportunities, and challenges of Limosillactobacillus reuteri-based probiotic dietary strategies

Limosillactobacillus reuteri (L. reuteri), a type of Lactobacillus spp., stands out as the most extensively researched probiotic. Its remarkable intestinal adhesion has led to widespread applications in both the food and medical sectors. Notably, recent research highlights the probiotic efficacy of L. reuteri sourced from breast milk, particularly in influencing social behavior and mitigating atopic dermatitis. In this review, our emphasis is on surveying recent literature regarding the promotion of host's health by L. reuteri. We aim to provide a concise summary of the latest regulatory effects and potential mechanisms attributed to L. reuteri in the realms of metabolism, brain- and immune-related functions. The mechanism through which L. reuteri promotes host health by modulating the intestinal microenvironment primarily involves promoting intestinal epithelial renewal, bolstering intestinal barrier function, regulating gut microbiota and its metabolites, and suppressing inflammation and immune responses. Additionally, this review delves into new technologies, identifies shortcomings, and addresses challenges in current L. reuteri research. Finally, the application prospects of L. reuteri are provided. Therefore, a better understanding of the role and mechanisms of L. reuteri will contribute significantly to the development of new probiotic functional foods and enable precise, targeted interventions for various diseases.

The Role of the Gut Microbiome in the Development of Acute Pancreatitis

With the explosion research on the gut microbiome in the recent years, much insight has been accumulated in comprehending the crosstalk between the gut microbiota community and host health. Acute pancreatitis (AP) is one of the gastrointestinal diseases associated with significant morbidity and subsequent mortality. Studies have elucidated that gut microbiota are engaged in the pathological process of AP. Herein, we summarize the major roles of the gut microbiome in the development of AP. We then portray the association between dysbiosis of the gut microbiota and the severity of AP. Finally, we illustrate the promises and challenges that arise when seeking to incorporate the microbiome in acute pancreatitis treatment.

Probiotic significance of Lactobacillus strains: a comprehensive review on health impacts, research gaps, and future prospects

A rising corpus of research has shown the beneficial effects of probiotic Lactobacilli on human health, contributing to the growing popularity of these microorganisms in recent decades. The gastrointestinal and urinary tracts are home to these bacteria, which play a vital role in the microbial flora of both humans and animals. The Lactobacillus probiotic, i.e, Lactobacillus plantarum, Lactobacillus paracasei, Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus reuteri, and Lactobacillus bulgaricus, are highly recognized for their remarkable probiotic qualities. The current study aims to highlight the beneficial effects of probiotics in different health conditions, point out the research gap, and highlight the future directives for the safe use of these probiotics in several health issues. Most importantly, we have added the most recent literature related to the characteristics and usage of these probiotics in clinical and pre-clinical settings. Based on the above statement, we believe that this is the first report on the application of probiotics in human diseases. By providing a deeper knowledge of the complex functions these probiotics play in both human and animal health, our analysis will direct future studies and developments in this rapidly developing field.