Microbial metabolites and immunotherapy: Basic rationale and clinical indications

The effect of immunotherapy PD-1 blockade on acute bone cancer pain: Insights from transcriptomic and microbiomic profiling

INTRODUCTION

The skeletal system ranks as the third most common site for cancer metastasis, often leading to pain with nociceptive and neuropathic features. Programmed cell death protein 1 (PD-1)-targeting therapeutic antibodies offer effective cancer treatment but can cause treatment-related acute pain. Understanding the mechanisms of this pain and identifying potential interventions is still a challenge.

METHODS

A murine model of bone cancer pain was established using Lewis lung carcinoma (LLC) cells, followed by intravenous administration of nivolumab, a human anti-PD-1 monoclonal antibody. Pain thresholds were measured, and micro-CT images of the skeletal system were obtained. High-throughput sequencing of the spinal cord/colon transcriptome during the acute phase of bone cancer pain and gut microbiota analysis at the end of the treatment were performed. Immunofluorescence staining and western blot experiments assessed spinal cord microglia activation and acute pain-associated molecules.

RESULTS

PD-1 inhibition with nivolumab protected against bone degradation initiated by LLC cell administration but consistently induced acute pain during nivolumab treatment. Spinal cord and colon transcriptomics revealed an immunopathological pattern during tumor progression and the acute pain phase, with notable changes in interleukin and S100 gene families. Gut microbiota analysis post-immunotherapy showed a decline in beneficial bacteria associated with short-chain fatty acid (SCFA) production. Activation of spinal cord microglia and enhanced glycolytic metabolism were confirmed as key factors in inducing acute pain following immunotherapy.

CONCLUSIONS

This study reveals that nivolumab induces acute pain by activating microglia and enhancing glycolytic metabolism in the treatment of bone cancer and uncovers connections between transcriptomic changes, gut microbiota, and acute pain following immune checkpoint blockade (ICB) treatment. It offers novel insights into the relationship between immune checkpoint blockade therapies and pain management.

Metabolic interactions of host-gut microbiota: New possibilities for the precise diagnosis and therapeutic discovery of gastrointestinal cancer in the future-A review

Gastrointestinal (GI) cancer continues to pose a significant global health challenge. Recent advances in our understanding of the complex relationship between the host and gut microbiota have shed light on the critical role of metabolic interactions in the pathogenesis and progression of GI cancer. In this study, we examined how microbiota interact with the host to influence signalling pathways that impact the formation of GI tumours. Additionally, we investigated the potential therapeutic approach of manipulating GI microbiota for use in clinical settings. Revealing the complex molecular exchanges between the host and gut microbiota facilitates a deeper understanding of the underlying mechanisms that drive cancer development. Metabolic interactions hold promise for the identification of microbial signatures or metabolic pathways associated with specific stages of cancer. Hence, this study provides potential strategies for the diagnosis, treatment and management of GI cancers to improve patient outcomes.

Multi-omics and bioinformatics for the investigation of therapeutic mechanism of roucongrong pill against postmenopausal osteoporosis

ETHNOPHARMACOLOGICAL RELEVANCE

The Roucongrong Pill (RCRP), originating from the historical General Medical Collection of Royal Benevolence, is frequently used to treat postmenopausal osteoporosis (PMOP). Despite its prevalent application, the specific anti-osteoporotic mechanisms of RCRP remain to be elucidated.

AIM OF THE STUDY

This study aims to elucidate the therapeutic mechanism of RCRP in the context of ovariectomy (OVX)-induced PMOP in rats. By employing an integrative approach, the research combines medicinal chemistry, gut microbiota (GM) profiling, metabolomics, MetOrigin traceability, network pharmacology, molecular docking, and molecular dynamics simulations to deliver a comprehensive analysis.

MATERIALS AND METHODS

Sprague-Dawley (SD) rats underwent bilateral OVX to establish a PMOP model. The therapeutic efficacy of RCRP was evaluated through bone metrics (BMD, bone strength, BV/TV, Tb.Sp), hematoxylin and eosin (H&E) histological assessment, and bone metabolism markers (OPG, BALP, TRACP-5b, β-CTX, RANKL). Fecal metabolomics and 16S rDNA sequencing were employed to assess the influence of RCRP on GM and metabolite profiles. Furthermore, MetOrigin facilitated the traceability analysis of relevant metabolites. Molecular docking identified potential RCRP compounds with anti-PMOP activity, while their stability and protein interactions were assessed through molecular dynamics simulations. Network pharmacology further confirms the targets of action.

RESULTS

RCRP alleviated PMOP in rats, enhancing bone strength, cortical and trabecular BMD, BV/TV, and serum OPG levels, while reducing Tb.Sp, serum BALP, TRACP-5b, β-CTX, and RANKL concentrations. A total of twenty-six distinct metabolites were identified, of which ten-tribufos, sulfoacetic acid, betamethasone dipropionate, 9-oxooctadeca-10,12,15-trienoic acid, menatetrenone, piperlongumine, maltopentaose, enol-phenylpyruvate, catechol, pentaacetate, and (+)-2-methylpropanoic acid-exhibited correlations with six GM species: Turicibacter, Roseburia, Colidextribacter, Helicobacter, Odoribacter, and Lachnoclostridium, as determined by Spearman's correlation analysis. Notably, MetOrigin revealed the microbial metabolism of taurine and hypotaurine, along with host-specific steroid hormone synthesis. Computational docking studies demonstrated robust interactions between five RCRP-derived steroids (hydroxyecdysone, corticosterone, trilostane, 5α-androstan-3,6,17-trione, and cortisol) and key enzymes (estradiol 17α-dehydrogenase and UDP-glucuronosyltransferase), suggesting a potential enhancement of therapeutic efficacy against PMOP. Furthermore, molecular dynamics simulations indicated stable interactions between hydroxyecdysone and two proteins, with binding free energies of -67.427 kJ/mol and -156.948 kJ/mol, respectively. Through network pharmacology and molecular docking approaches, potential targets of these metabolites were identified, including estrogen receptors ESR1 and ESR2, dual specificity phosphatase 6 (DUSP6), sex hormone-binding globulin (SHBG), prostaglandin E receptor 4 (PTGER4), cannabinoid receptor 2 (CNR2), cathepsin K (CTSK), and androgen receptor (AR).

CONCLUSIONS

RCRP effectively mitigates OVX-induced bone loss in PMOP rats by modulating GM and associated metabolites, along with their potential targets and key metabolic pathways, including taurine and hypotaurine metabolism, as well as steroid hormone biosynthesis. These findings offer new insights into the therapeutic mechanisms by which RCRP may alleviate PMOP.

Metabolic mediators: microbial-derived metabolites as key regulators of anti-tumor immunity, immunotherapy, and chemotherapy

The human microbiome has recently emerged as a focal point in cancer research, specifically in anti-tumor immunity, immunotherapy, and chemotherapy. This review explores microbial-derived metabolites, emphasizing their crucial roles in shaping fundamental aspects of cancer treatment. Metabolites such as short-chain fatty acids (SCFAs), Trimethylamine N-Oxide (TMAO), and Tryptophan Metabolites take the spotlight, underscoring their diverse origins and functions and their profound impact on the host immune system. The focus is on SCFAs' remarkable ability to modulate immune responses, reduce inflammation, and enhance anti-tumor immunity within the intricate tumor microenvironment (TME). The review critically evaluates TMAO, intricately tied to dietary choices and gut microbiota composition, assessing its implications for cancer susceptibility, progression, and immunosuppression. Additionally, the involvement of tryptophan and other amino acid metabolites in shaping immune responses is discussed, highlighting their influence on immune checkpoints, immunosuppression, and immunotherapy effectiveness. The examination extends to their dynamic interaction with chemotherapy, emphasizing the potential of microbial-derived metabolites to alter treatment protocols and optimize outcomes for cancer patients. A comprehensive understanding of their role in cancer therapy is attained by exploring their impacts on drug metabolism, therapeutic responses, and resistance development. In conclusion, this review underscores the pivotal contributions of microbial-derived metabolites in regulating anti-tumor immunity, immunotherapy responses, and chemotherapy outcomes. By illuminating the intricate interactions between these metabolites and cancer therapy, the article enhances our understanding of cancer biology, paving the way for the development of more effective treatment options in the ongoing battle against cancer.

Gut microbiota and metabolites signatures of clinical response in anti-PD-1/PD-L1 based immunotherapy of biliary tract cancer

BACKGROUND

Accumulating evidence suggests that the gut microbiota and metabolites can modulate tumor responses to immunotherapy; however, limited data has been reported on biliary tract cancer (BTC). This study used metagenomics and metabolomics to identify characteristics of the gut microbiome and metabolites in immunotherapy-treated BTC and their potential as prognostic and predictive biomarkers.

METHODS

This prospective cohort study enrolled 88 patients with BTC who received PD-1/PD-L1 inhibitors from November 2018 to May 2022. The microbiota and metabolites significantly enriched in different immunotherapy response groups were identified through metagenomics and LC-MS/MS. Associations between microbiota and metabolites, microbiota and clinical factors, and metabolites and clinical factors were explored.

RESULTS

Significantly different bacteria and their metabolites were both identified in the durable clinical benefit (DCB) and non-durable clinical benefit (NDB) groups. Of these, 20 bacteria and two metabolites were significantly associated with survival. Alistipes were positively correlated with survival, while Bacilli, Lactobacillales, and Pyrrolidine were negatively correlated with survival. Predictive models based on six bacteria, four metabolites, and the combination of three bacteria and two metabolites could all discriminated between patients in the DCB and NDB groups with high accuracy. Beta diversity between two groups was significantly different, and the composition varied with differences in the use of immunotherapy.

CONCLUSIONS

Patients with BTC receiving immunotherapy have specific alterations in the interactions between microbiota and metabolites. These findings suggest that gut microbiota and metabolites are potential prognostic and predictive biomarkers for clinical outcomes of anti-PD-1/PD-L1-treated BTC.

BioCanRx Summit for Cancer Immunotherapy 2022 Proceedings

From 19 to 21 November 2022, BioCanRx held its first post-pandemic in-person Summit for Cancer Immunotherapy in Montreal, Canada. The meeting was well attended by patients, trainees, researchers, clinicians, and industry professionals, who came together to discuss the current state and future of biotherapeutics for cancer in Canada and beyond. Three plenaries, three keynote speakers, a lively debate, and panel discussions, together with poster sessions and a social event, made the event memorable and productive. The current state of cellular therapies, cellular engineering, clinical trials, and the role of the cancer microbiome were discussed in plenary session, and the patient voice was welcomed and present throughout the meeting, in large part due to the Learning Institute, a BioCanRx initiative to include patient partners in research. In this meeting review, we highlight the platform presentations, keynote speakers, debate combatants, panellists, and the patient perspective on the annual meeting.

Gut Metabolite Indoxyl Sulfate Has Selective Deleterious and Anticancer Effect on Colon Cancer Cells

There are a number of reports about anticancer activity of indole derivatives. In this study, we investigated the role of indoxyl sulfate (IS) for its selective anticancer activity on colon cancer cells. IS treatment on HCT-116 and HT-29 human epithelial adenocarcinoma cells led to a decrease in cell proliferation, cell viability, and ATP content. Colon cancer cells showed a 10% increase in cell apoptosis in comparison to control. Due to IS treatment, cell morphology got distorted, cell number found decreased, intracellular vesicles formed, and cells were found floating in the media. Cells also showed a loss in membrane integrity and a decrease in colony-forming ability and ceased at the G2/M phase of the cell cycle. No significant change was noted in the level of inflammatory cytokines IL-17A, IL-1β, and TNF-α, histology, length of intestine, and spleen after 100 mM IS treatment to balb/c mice. These observations indicate the selective anticancer effect of IS on colon cancer cells.

Drug Repurposing to Circumvent Immune Checkpoint Inhibitor Resistance in Cancer Immunotherapy

Immune checkpoint inhibitors (ICI) have achieved unprecedented clinical success in cancer treatment. However, drug resistance to ICI therapy is a major hurdle that prevents cancer patients from responding to the treatment or having durable disease control. Drug repurposing refers to the application of clinically approved drugs, with characterized pharmacological properties and known adverse effect profiles, to new indications. It has also emerged as a promising strategy to overcome drug resistance. In this review, we summarized the latest research about drug repurposing to overcome ICI resistance. Repurposed drugs work by either exerting immunostimulatory activities or abolishing the immunosuppressive tumor microenvironment (TME). Compared to the de novo drug design strategy, they provide novel and affordable treatment options to enhance cancer immunotherapy that can be readily evaluated in the clinic. Biomarkers are exploited to identify the right patient population to benefit from the repurposed drugs and drug combinations. Phenotypic screening of chemical libraries has been conducted to search for T-cell-modifying drugs. Genomics and integrated bioinformatics analysis, artificial intelligence, machine and deep learning approaches are employed to identify novel modulators of the immunosuppressive TME.