The probiotic Lactobacillus rhamnosus GG (LGG) restrains the angiogenic potential of colorectal carcinoma cells by activating a pro-resolving program via formyl peptide receptor 1

Formyl peptide receptor 1 signaling strength orchestrates the switch from pro-inflammatory to pro-resolving responses: The way to exert its anti-angiogenic and tumor suppressor functions

The well-paced trigger of inflammation resolution following an inflammatory response is crucial for tissue homeostasis and cancer. In gastrointestinal tumors the Formyl peptide receptor 1 (FPR1) stimulates an inflammation resolution response able to restrain cancer angiogenesis and growth. A preceding inflammatory signal is necessary for the induction of the pro-resolving response. However, if FPR1-induced inflammation resolution and tumor suppressor function require an early pro-inflammatory trigger and how this is achieved remains unknown. A ROS-dependent signaling is activated in response to FPR1 activation. In colorectal carcinoma (CRC) cells, we carefully analyzed this signal showing that FPR1 activation by the fMLF peptide induces biphasic ROS production: a first wave, early, mitochondrial (mROS), followed by a second, late, NADPH oxidase (NOX1)-dependent. mROS cause SHP2 phosphatase inactivation restraining its ability to dephosphorylate and inactivate SRC. SRC, in turn, allows the activation of RAS and Rac1 GTPases. RAS activates MAPK signaling, while Rac1 supports NOX1 activation, that causes the second wave of ROS, reinforcing this signaling cycle. Importantly, for the first time, we demonstrate that mROS production precedes and is necessary for pro-inflammatory mediators' release, while NOX1-dependent ROS are only required for pro-resolving mediators' synthesis. Pharmacological and genetic approaches and functional assays show that this signaling cascade is essential for the pro-resolving and anti-angiogenic properties of FPR1 in CRC. In conclusion, we show that FPR1 elicits pro-resolving effects in CRC activating two waves of ROS production characterized by different strength and kinetics, that parallel and are necessary for pro-inflammatory or pro-resolving mediators' production.

The N-formyl peptide receptors: much more than chemoattractant receptors. Relevance in health and disease

Pattern Recognition Receptors (PRRs) are a superfamily of receptors that detect molecular structures typical for pathogens and damaged cells and play a crucial role in the proper function of the innate immune system. A particular subgroup of membrane-bound PRRs is represented by the N-formyl peptide receptors (FPRs) that consist of transmembrane G-protein coupled receptors involved in inflammatory responses. FPRs were initially described in immune cells as transducers of chemotactic signals in phagocytes that react to tissue injury. Subsequently, FPRs were also identified in a wide variety of cell types, including cancer cells. Beyond broad cellular distribution, FPRs are also characterized by the ability to bind a variety of ligands with different chemical and biological properties, ranging from natural peptides to synthetic compounds. The binding of FPRs to specific agonists induces a cascade of functional biological events, such as cell proliferation, migration, angiogenesis, and oxidative stress. From all this evidence, it becomes clear that FPRs are multifaceted receptors involved in several pathophysiological processes associated with inflammation. In this review, we provide a comprehensive molecular description of structure-function relationship of FPRs and their pivotal role in the host defense, highlighting the regulatory functions in both the initiation and resolution of inflammation. In addition to their activity as PRRs during innate immune response, we focus on their involvement in pathological conditions, including chronic inflammatory disease, neurodegenerative disorders, and cancer, with special emphasis on FPR targeting as promising therapeutic strategies in the era of precision medicine.

Mediation role of body mass index in the relationship between food-specific serum immunoglobulin G reactivity and colorectal adenomas in a Chinese population: a cross-sectional study

Background

Colorectal adenomas (CAs) represent a significant global health issue, particularly in China, where lifestyle modifications have contributed to their increased prevalence. These adenomas are precursors to colorectal cancer. While high-fiber diets have been shown to decrease risk, the implications of food-specific serum immunoglobulin G reactivity (FSsIgGR) on CAs remain uncertain and warrant further investigation.

Objectives

To investigate the association between FSsIgGR and the occurrence of CAs in the Chinese population, assess the mediating influence of body mass index (BMI), and offer insights into potential prevention strategies.

Design

A retrospective cross-sectional study.

Methods

This study is based on 8796 individuals who underwent colonoscopy at the Second Medical Center of Chinese PLA General Hospital from 2017 to 2021. We examined the relationship between FSsIgGR and CAs using logistic regression, controlling for various confounders. Interaction effects were explored through subgroup analysis. We addressed missing data using multiple imputation and confirmed the robustness of our findings through sensitivity analysis. The role of BMI as a mediator was quantified using structural equation modeling.

Results

The cohort comprised 2703 patients diagnosed with CAs and 6093 polyp-free controls, with an average age of 50.1 years, of whom 70.1% were male. The analysis revealed a significant inverse association between FSsIgGR and the incidence of CAs (adjusted odds ratio = 0.97; 95% confidence interval: 0.95-0.99; p < 0.001). Dose-response analysis indicated a linear reduction in CAs risk correlating with an increased number of IgG-positive food items. Structural equation modeling showed that BMI mediated 6.02% of the effect on CAs risk (p = 0.038).

Conclusion

Our findings suggest that FSsIgGR correlates with a reduced risk of developing CAs, with BMI partially mediating this effect. These results add a novel dimension to CAs risk assessment and prevention, highlighting potential dietary interventions.

Angiogenesis, a key point in the association of gut microbiota and its metabolites with disease

The gut microbiota is a complex and dynamic ecosystem that plays a crucial role in human health and disease, including obesity, diabetes, cardiovascular diseases, neurodegenerative diseases, inflammatory bowel disease, and cancer. Chronic inflammation is a common feature of these diseases and is closely related to angiogenesis (the process of forming new blood vessels), which is often dysregulated in pathological conditions. Inflammation potentially acts as a central mediator. This abstract aims to elucidate the connection between the gut microbiota and angiogenesis in various diseases. The gut microbiota influences angiogenesis through various mechanisms, including the production of metabolites that directly or indirectly affect vascularization. For example, short-chain fatty acids (SCFAs) such as butyrate, propionate, and acetate are known to regulate immune responses and inflammation, thereby affecting angiogenesis. In the context of cardiovascular diseases, the gut microbiota promotes atherosclerosis and vascular dysfunction by producing trimethylamine N-oxide (TMAO) and other metabolites that promote inflammation and endothelial dysfunction. Similarly, in neurodegenerative diseases, the gut microbiota may influence neuroinflammation and the integrity of the blood-brain barrier, thereby affecting angiogenesis. In cases of fractures and wound healing, the gut microbiota promotes angiogenesis by activating inflammatory responses and immune effects, facilitating the healing of tissue damage. In cancer, the gut microbiota can either inhibit or promote tumor growth and angiogenesis, depending on the specific bacterial composition and their metabolites. For instance, some bacteria can activate inflammasomes, leading to the production of inflammatory factors that alter the tumor immune microenvironment and activate angiogenesis-related signaling pathways, affecting tumor angiogenesis and metastasis. Some bacteria can directly interact with tumor cells, activating angiogenesis-related signaling pathways. Diet, as a modifiable factor, significantly influences angiogenesis through diet-derived microbial metabolites. Diet can rapidly alter the composition of the microbiota and its metabolic activity, thereby changing the concentration of microbial-derived metabolites and profoundly affecting the host's immune response and angiogenesis. For example, a high animal protein diet promotes the production of pro-atherogenic metabolites like TMAO, activating inflammatory pathways and interfering with platelet function, which is associated with the severity of coronary artery plaques, peripheral artery disease, and cardiovascular diseases. A diet rich in dietary fiber promotes the production of SCFAs, which act as ligands for cell surface or intracellular receptors, regulating various biological processes, including inflammation, tissue homeostasis, and immune responses, thereby influencing angiogenesis. In summary, the role of the gut microbiota in angiogenesis is multifaceted, playing an important role in disease progression by affecting various biological processes such as inflammation, immune responses, and multiple signaling pathways. Diet-derived microbial metabolites play a crucial role in linking the gut microbiota and angiogenesis. Understanding the complex interactions between diet, the gut microbiota, and angiogenesis has the potential to uncover novel therapeutic targets for managing these conditions. Therefore, interventions targeting the gut microbiota and its metabolites, such as through fecal microbiota transplantation (FMT) and the application of probiotics to alter the composition of the gut microbiota and enhance the production of beneficial metabolites, present a promising therapeutic strategy.

Metabolic Characteristics of Gut Microbiota and Insomnia: Evidence from a Mendelian Randomization Analysis

Insomnia is a common sleep disorder that significantly impacts individuals' sleep quality and daily life. Recent studies have suggested that gut microbiota may influence sleep through various metabolic pathways. This study aims to explore the causal relationships between the abundance of gut microbiota metabolic pathways and insomnia using Mendelian randomization (MR) analysis. This two-sample MR study used genetic data from the OpenGWAS database (205 gut bacterial pathway abundance) and the FinnGen database (insomnia-related data). We identified single nucleotide polymorphisms (SNPs) associated with gut bacterial pathway abundance as instrumental variables (IVs) and ensured their validity through stringent selection criteria and quality control measures. The primary analysis employed the inverse variance-weighted (IVW) method, supplemented by other MR methods, to estimate causal effects. The MR analysis revealed significant positive causal effects of specific carbohydrate, amino acid, and nucleotide metabolism pathways on insomnia. Key pathways, such as gluconeogenesis pathway (GLUCONEO.PWY) and TCA cycle VII acetate producers (PWY.7254), showed positive associations with insomnia (B > 0, p < 0.05). Conversely, pathways like hexitol fermentation to lactate, formate, ethanol and acetate pathway (P461.PWY) exhibited negative causal effects (B < 0, p < 0.05). Multivariable MR analysis confirmed the independent causal effects of these pathways (p < 0.05). Sensitivity analyses indicated no significant pleiotropy or heterogeneity, ensuring the robustness of the results. This study identifies specific gut microbiota metabolic pathways that play critical roles in the development of insomnia. These findings provide new insights into the biological mechanisms underlying insomnia and suggest potential targets for therapeutic interventions. Future research should further validate these causal relationships and explore how modulating gut microbiota or its metabolic products can effectively improve insomnia symptoms, leading to more personalized and precise treatment strategies.

Anticancer Potential of Postbiotic Derived from Lactobacillus brevis and Lactobacillus casei: In vitro Analysis of Breast Cancer Cell Line

Breast cancer has emerged as the most widespread and dangerous type of malignancy among women worldwide. Postbiotics have recently emerged as a promising novel adjunct in breast cancer therapy, due to their immunomodulatory effects and the potential to mitigate the adverse effects of conventional treatments. This study aims to investigate the therapeutic effects of postbiotics derived from Lactobacillus brevis (CSF2) and Lactobacillus casei (CFS5), specifically examining their ability to inhibit cell proliferation and induce apoptosis in MCF-7 breast cancer cells. In the current study, the anticancer activity of the cell-free supernatant of L. brevis and L. casei was investigated against MCF-7 cells using MTT assay, flow cytometry, and qRT-PCR technique. Both bacteria showed a high potential for the induction of cell death in MCF-7 cells. However, CFS2 cytotoxicity was significantly higher than CFS5. Flow cytometry results showed significant induction of early apoptosis in cells treated with both CFS2 and CFS5 within 48 h. The induction was notably higher in cells treated with CFS2 compared to CFS5. Overall, CFS2 therapy resulted in a greater increase in BAX and CASP9 gene expression, as well as an elevated BAX/BCL2 ratio within 48 h. These findings indicate that the CFS2 treatment showed a higher level of apoptotic activity than the CFS5 treatment. High biocompatibility was demonstrated following treatment with CFS2 and CFS5. These CFSs may serve as adjunctive medications for suppressing the proliferation of cancer cells. The results of the current study highlight the potential of postbiotics in cancer treatment and suggest that supernatants may serve as effective agents for suppressing cancer cell growth and viability.

Mechanisms by which the intestinal microbiota affects gastrointestinal tumours and therapeutic effects

The intestinal microbiota is considered to be a forgotten organ in human health and disease. It maintains intestinal homeostasis through various complex mechanisms. A significant body of research has demonstrated notable differences in the gut microbiota of patients with gastrointestinal tumours compared to healthy individuals. Furthermore, the dysregulation of gut microbiota, metabolites produced by gut bacteria, and related signal pathways can partially explain the mechanisms underlying the occurrence and development of gastrointestinal tumours. Therefore, this article summarizes the latest research progress on the gut microbiota and gastrointestinal tumours. Firstly, we provide an overview of the composition and function of the intestinal microbiota and discuss the mechanisms by which the intestinal flora directly or indirectly affects the occurrence and development of gastrointestinal tumours by regulating the immune system, producing bacterial toxins, secreting metabolites. Secondly, we present a detailed analysis of the differences of intestinal microbiota and its pathogenic mechanisms in colorectal cancer, gastric cancer, hepatocellular carcinoma, etc. Lastly, in terms of treatment strategies, we discuss the effects of the intestinal microbiota on the efficacy and toxic side effects of chemotherapy and immunotherapy and address the role of probiotics, prebiotics, FMT and antibiotic in the treatment of gastrointestinal tumours. In summary, this article provides a comprehensive review of the pathogenic mechanisms of and treatment strategies pertaining to the intestinal microbiota in patients with gastrointestinal tumours. And provide a more comprehensive and precise scientific basis for the development of microbiota-based treatments for gastrointestinal tumours and the prevention of such tumours.

Tumor-resident Lactobacillus iners confer chemoradiation resistance through lactate-induced metabolic rewiring

Tumor microbiota can produce active metabolites that affect cancer and immune cell signaling, metabolism, and proliferation. Here, we explore tumor and gut microbiome features that affect chemoradiation response in patients with cervical cancer using a combined approach of deep microbiome sequencing, targeted bacterial culture, and in vitro assays. We identify that an obligate L-lactate-producing lactic acid bacterium found in tumors, Lactobacillus iners, is associated with decreased survival in patients, induces chemotherapy and radiation resistance in cervical cancer cells, and leads to metabolic rewiring, or alterations in multiple metabolic pathways, in tumors. Genomically similar L-lactate-producing lactic acid bacteria commensal to other body sites are also significantly associated with survival in colorectal, lung, head and neck, and skin cancers. Our findings demonstrate that lactic acid bacteria in the tumor microenvironment can alter tumor metabolism and lactate signaling pathways, causing therapeutic resistance. Lactic acid bacteria could be promising therapeutic targets across cancer types.

Unleashing the power of formyl peptide receptor 2 in cardiovascular disease

N-formyl peptide receptors (FPRs) are seven-transmembrane, G protein-coupled receptors with a wide distribution in immune and non-immune cells, recognizing N-formyl peptides from bacterial and mitochondrial origin and several endogenous signals. Three FPRs have been identified in humans: FPR1, FPR2, and FPR3. Most FPR ligands can activate a pro-inflammatory response, while a limited group of FPR agonists can elicit anti-inflammatory and homeostatic responses. Annexin A1 (AnxA1), a glucocorticoid-induced protein, its N-terminal peptide Ac2-26, and lipoxin A4 (LXA4), a lipoxygenase-derived eicosanoid mediator, exert significant immunomodulatory effects by interacting with FPR2 and/or FPR1. The ability of FPRs to recognize both ligands with pro-inflammatory or inflammation-resolving properties places them in a crucial position in the balance between activation against harmful events and maintaince of tissue integrity. A new field of investigation focused on the role of FPRs in the setting of heart injury. FPRs are expressed on cardiac macrophages, which are the predominant immune cells in the myocardium and play a key role in heart diseases. Several endogenous (AnxA1, LXA4) and synthetic compounds (compound 43, BMS-986235) reduced infarct size and promoted the resolution of inflammation via the activation of FPR2 on cardiac macrophages. Further studies should evaluate FPR2 role in other cardiovascular disorders.

The lncRNA RMST is drastically downregulated in anaplastic thyroid carcinomas where exerts a tumor suppressor activity impairing epithelial-mesenchymal transition and stemness

Thyroid cancer is the most prevalent endocrine malignancy and comprises a wide range of lesions subdivided into differentiated (DTC) and undifferentiated thyroid cancer (UTC), mainly represented by the anaplastic thyroid carcinoma (ATC). This is one of the most lethal malignancies in humankind leading invariably to patient death in few months. Then, a better comprehension of the mechanisms underlying the development of ATC is required to set up new therapeutic approaches. Long non-coding RNAs (lncRNAs) are transcripts over 200 nucleotides in length that do not code for proteins. They show a strong regulatory function at both transcriptional and post-transcriptional level and are emerging as key players in regulating developmental processes. Their aberrant expression has been linked to several biological processes, including cancer, making them potential diagnostic and prognostic markers. We have recently analyzed the lncRNA expression profile in ATC through a microarray technique and have identified rhabdomyosarcoma 2-associated transcript (RMST) as one of the most downregulated lncRNA in ATC. RMST has been reported to be deregulated in a series of human cancers, to play an anti-oncogenic role in triple-negative breast cancer, and to modulate neurogenesis by interacting with SOX2. Therefore, these findings prompted us to investigate the role of RMST in ATC development. In this study we show that RMST levels are strongly decreased in ATC, but only slightly in DTC, indicating that the loss of this lncRNA could be related to the loss of the differentiation and high aggressiveness. We also report a concomitant increase of SOX2 levels in the same subset of ATC, that inversely correlated with RMST levels, further supporting the RMST/SOX2 relationship. Finally, functional studies demonstrate that the restoration of RMST in ATC cells reduces cell growth, migration and the stemness properties of ATC stem cells. In conclusion, these findings support a critical role of RMST downregulation in ATC development.

Lactobacillus rhamnosus GG cell-free supernatant as a novel anti-cancer adjuvant

BACKGROUND

Gut microbiota modulation has been demonstrated to be effective in protecting patients against detrimental effects of anti-cancer therapies, as well as to improve the efficacy of certain anti-cancer treatments. Among the most characterized probiotics, Lactobacillus rhamnosus GG (LGG) is currently utilized in clinics to alleviate diarrhea, mucositis or intestinal damage which might be associated with several triggers, including Clostridium difficile infections, inflammatory gut diseases, antibiotic consumption, chemotherapy or radiation therapy. Here, we investigate whether LGG cell-free supernatant (LGG-SN) might exert anti-proliferative activity toward colon cancer and metastatic melanoma cells. Moreover, we assess the potential adjuvant effect of LGG-SN in combination with anti-cancer drugs.

METHODS

LGG-SN alone or in combination with either 5-Fuorouracil and Irinotecan was used to treat human colon and human melanoma cancer cell lines. Dimethylimidazol-diphenyl tetrazolium bromide assay was employed to detect cellular viability. Trypan blue staining, anti-cleaved caspase-3 and anti-total versus anti-cleaved PARP western blots, and annexin V/propidium iodide flow cytometry analyses were used to assess cell death. Flow cytometry measurement of cellular DNA content (with propidium iodide staining) together with qPCR analysis of cyclins expression were used to assess cell cycle.

RESULTS

We demonstrate that LGG-SN is able to selectively reduce the viability of cancer cells in a concentration-dependent way. While LGG-SN does not exert any anti-proliferative activity on control fibroblasts. In cancer cells, the reduction in viability is not associated with apoptosis induction, but with a mitotic arrest in the G2/M phase of cell cycle. Additionally, LGG-SN sensitizes cancer cells to both 5-Fluorouracil and Irinotecan, thereby showing a positive synergistic action.

CONCLUSION

Overall, our results suggest that LGG-SN may contain one or more bioactive molecules with anti-cancer activity which sensitize cancer cells to chemotherapeutic drugs. Thus, LGG could be proposed as an ideal candidate for ground-breaking integrated approaches to be employed in oncology, to reduce chemotherapy-related side effects and overcome resistance or relapse issues, thus ameliorating the therapeutic response in cancer patients.

The Impact of Resolution of Inflammation on Tumor Microenvironment: Exploring New Ways to Control Cancer Progression

Non-resolving inflammation is an enabling feature of cancer. A novel super-family of lipid mediators termed Specialized Pro-resolving Mediators (SPMs) have a role as bioactive molecules mediating the resolution of inflammation in cancer biology. SPMs are derived from ω-3 and ω-6 polyunsaturated fatty acids through the activity of lipoxygenases. SPMs have been described to directly modulate cancer progression by interfering with the epithelial to mesenchymal transition and invasion of cancer cells. SPMs have also been demonstrated to act on several components of the tumor microenvironment (TME). Consistently with their natural immunomodulatory and anti-inflammatory properties, SPMs are able to reprogram macrophages to favor phagocytosis of cell debris, which are an important source of pro-inflammatory and pro-angiogenic signals; sustain a direct cytotoxic immune response against cancer cells; stimulate neutrophils anti-tumor activities; and inhibit the development of regulatory T and B cells, thus indirectly leading to enhanced anti-tumor immunity. Furthermore, the resolution pathways exert crucial anti-angiogenic functions in lung, liver, and gastrointestinal cancers, and inhibit cancer-associated fibroblast differentiation and functions in hepatocellular carcinoma and pancreatic cancer. The present review will be focused on the potential protective effects of resolution pathways against cancer, exerted by modulating different components of the TME.