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

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.

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.

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.