Bidirectional Functional Effects of Staphylococcus on Carcinogenesis

Lung Microbiome in Lung Cancer: A New Horizon in Cancer Study

Lung cancer is the second most prevalent cancer worldwide and a leading cause of cancer-related deaths. Recent technological advancements have revealed that the lung microbiome, previously thought to be sterile, is host to various microorganisms. The association between the lung microbiome and lung cancer initiation, progression, and metastasis is complex and contradictory. However, disruption in the homeostasis of microbiome compositions correlated with the increased risk of lung cancer. This review summarizes current knowledge about the most recent developments and trends in lung cancer-related microbiota or microbial components. This article aims to provide information on this rapidly evolving field while giving context to the general role of the lung microbiome in lung cancer. In addition, this review briefly discussed the causative association of lung microbiome with lung cancer. We will review the mechanisms by which lung microbiota influence carcinogenesis, focusing on microbiota dysbiosis. Moreover, we will also discuss the host-microbiome interaction as it plays a crucial role in stimulating and regulating the immune response. Finally, we will provide information on the diagnostic role of the microbiome in lung cancer. This article aims to offer an overview of the lung microbiome as a predictive and diagnostic biomarker in lung cancer.

Microbial mysteries: Staphylococcus aureus and the enigma of carcinogenesis

Staphylococcus aureus, a common human pathogen, has long been the focus of scientific investigation due to its association with various infections. However, recent research has unveiled a tantalizing enigma surrounding this bacterium and its potential involvement in carcinogenesis. Chronic S. aureus infections have been linked to an elevated risk of certain cancers, including skin cancer and oral cancer. This review explores the current state of knowledge regarding this connection, examining epidemiological evidence, pathogenic mechanisms, and biological interactions that suggest a correlation. Although initial studies point to a possible link, the precise mechanisms through which S. aureus may contribute to cancer development remain elusive. Emerging evidence suggests that the chronic inflammation induced by persistent S. aureus infections may create a tumor-promoting environment. This inflammation can lead to DNA damage, disrupt cellular signaling pathways, and generate an immunosuppressive microenvironment conducive to cancer progression. Additionally, S. aureus produces a variety of toxins and metabolites that can directly interact with host cells, potentially inducing oncogenic transformations. Despite these insights, significant gaps remain in our understanding of the exact biological processes involved. This review emphasizes the urgent need for more comprehensive research to clarify these microbiological mysteries. Understanding the role of S. aureus in cancer development could lead to novel strategies for cancer prevention and treatment, potentially transforming therapeutic approaches.

Diabetic Patient with CA-MRSA Pneumonia and Plasma Cell Neoplasm: A Case Report of Severe Complications and Prognosis

BACKGROUND The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) has been increasing in recent years, becoming a cause of community-acquired infection. Interestingly, its role in malignancy recently started to be considered after a noticed increase in reported cases and studies discussing the potential association. CASE REPORT In the present case, the patient had known and uncontrolled diabetes mellitus and a history of multiple abscesses that were previously treated by incision and drainage. The patient received a diagnosis of severe pneumonia, and MRSA was found in blood cultures. Further tests for HIV, hemagglutinin type 1, and neuraminidase type 1 (H1N1) were negative. The D test was also performed for macrolide-inducible resistance and was negative, indicating the need for intravenous administration of clindamycin. An echocardiogram ruled out endocarditis. Subsequently, the patient experienced progressive back pain and weakness involving the lower limbs. A pathological fracture was discovered, along with nerve root compression. An urgent posterior spine fixation was then performed by a neurosurgeon. A biopsy was collected at the site of the pathological fracture, and histopathological tests indicated a plasma cell neoplasm. CONCLUSIONS MRSA is known to cause serious and dangerous infections, including necrotizing pneumonia. Furthermore, a link between MRSA and plasma cell dyscrasia has been considered in several reports. This necessitates the need for further studies to clarify this hidden association, which may help in the course and prognosis of these patients.

Causal roles of skin microbiota in skin cancers suggested by genetic study

Background

There is evidence from observational studies that skin microbiota is linked to skin cancers. Nevertheless, the causal association between skin microbiota and skin cancers is yet to be fully clarified.

Methods

A bidirectional two-sample Mendelian randomization (MR) was performed to determine the causal relationship between skin microbiota and skin cancers. A total of 294 skin microbial taxa were identified from the first genome-wide association study across three skin microenvironments of two German population cohorts. Summary data of three skin cancers (malignant melanoma, squamous cell carcinoma, and basal cell carcinoma) were obtained from the FinnGen consortium. Moreover, sensitivity analysis examined horizontal pleiotropy and heterogeneity, and microenvironment-based meta-analysis confirmed the reliability of the results.

Results

We identified 65 nominal causalities and 5 strong causal associations between skin microbiota and skin cancers. Among them, the class Bacilli revealed a bidirectional positive relationship with malignant melanoma. The class Betaproteobacteria and class Gammaproteobacteria demonstrated a causal association with an elevated risk of malignant melanoma and basal cell carcinoma, respectively. In the reverse MR analysis, malignant melanoma was associated with a lower abundance of phylum Bacteroidetes. There were no indications of significant heterogeneity in instrumental variables or evidence of horizontal pleiotropy.

Conclusion

Our MR analysis indicated bidirectional causal associations between skin microbiota and skin cancers, and had the potential to offer novel perspectives on the mechanistic of microbiota-facilitated carcinogenesis.

EGC enhances tumor antigen presentation and CD8+ T cell-mediated antitumor immunity via targeting oncoprotein SND1

The Staphylococcal nuclease and Tudor domain containing 1 (SND1) has been identified as an oncoprotein. Our previous study demonstrated that SND1 impedes the major histocompatibility complex class I (MHC-I) assembly by hijacking the nascent heavy chain of MHC-I to endoplasmic reticulum-associated degradation. Herein, we aimed to identify inhibitors to block SND1-MHC-I binding, to facilitate the MHC-I presentation and tumor immunotherapy. Our findings validated the importance of the K490-containing sites in SND1-MHC-I complex. Through structure-based virtual screening and docking analysis, (-)-Epigallocatechin (EGC) exhibited the highest docking score to prevent the binding of MHC-I to SND1 by altering the spatial conformation of SND1. Additionally, EGC treatment resulted in increased expression levels of membrane-presented MHC-I in tumor cells. The C57BL/6J murine orthotopic melanoma model validated that EGC increases infiltration and activity of CD8+ T cells in both the tumor and spleen. Furthermore, the combination of EGC with programmed death-1 (PD-1) antibody demonstrated a superior antitumor effect. In summary, we identified EGC as a novel inhibitor of SND1-MHC-I interaction, prompting MHC-I presentation to improve CD8+ T cell response within the tumor microenvironment. This discovery presents a promising immunotherapeutic candidate for tumors.

Oral administration of Manuka honey induces IFNγ-dependent resistance to tumor growth that correlates with beneficial modulation of gut microbiota composition

Background

To investigate the potential of Manuka honey (MH) as an immunomodulatory agent in colorectal cancer (CRC) and dissect the underlying molecular and cellular mechanisms.

Methods

MH was administered orally over a 4 week-period. The effect of MH treatment on microbiota composition was studied using 16S rRNA sequencing of fecal pellets collected before and after treatment. Pretreated mice were implanted with CRC cells and followed for tumor growth. Tumors and lymphoid organs were analyzed by flow cytometry (FACS), immunohistochemistry and qRT-PCR. Efficacy of MH was also assessed in a therapeutic setting, with oral treatment initiated after tumor implantation. We utilized IFNγ-deficient mice to determine the importance of interferon signaling in MH-induced immunomodulation.

Results

Pretreatment with MH enhanced anti-tumor responses leading to suppression of tumor growth. Evidence for enhanced tumor immunogenicity included upregulated MHC class-II on intratumoral macrophages, enhanced MHC class-I expression on tumor cells and increased infiltration of effector T cells into the tumor microenvironment. Importantly, oral MH was also effective in retarding tumor growth when given therapeutically. Transcriptomic analysis of tumor tissue highlighted changes in the expression of various chemokines and inflammatory cytokines that drive the observed changes in tumor immunogenicity. The immunomodulatory capacity of MH was abrogated in IFNγ-deficient mice. Finally, bacterial 16S rRNA sequencing demonstrated that oral MH treatment induced unique changes in gut microbiota that may well underlie the IFN-dependent enhancement in tumor immunogenicity.

Conclusion

Our findings highlight the immunostimulatory properties of MH and demonstrate its potential utilization in cancer prevention and treatment.

Cultivable Microbiome Approach Applied to Cervical Cancer Exploration

Traditional microbiological methodology is valuable and essential for microbiota composition description and microbe role assignations at different anatomical sites, including cervical and vaginal tissues; that, combined with molecular biology strategies and modern identification approaches, could give a better perspective of the microbiome under different circumstances. This pilot work aimed to describe the differences in microbiota composition in non-cancer women and women with cervical cancer through a culturomics approach combining culture techniques with Vitek mass spectrometry and 16S rDNA sequencing. To determine the possible differences, diverse statistical, diversity, and multivariate analyses were applied; the results indicated a different microbiota composition between non-cancer women and cervical cancer patients. The Firmicutes phylum dominated the non-cancer (NC) group, whereas the cervical cancer (CC) group was characterized by the predominance of Firmicutes and Proteobacteria phyla; there was a depletion of lactic acid bacteria, an increase in the diversity of anaerobes, and opportunistic and non-typical human microbiota isolates were present. In this context, we hypothesize and propose a model in which microbial composition and dynamics may be essential for maintaining the balance in the cervical microenvironment or can be pro-oncogenesis microenvironmental mediators in a process called Ying-Yang or have a protagonist/antagonist microbiota role.

Characterization of immunomodulating agents from Staphylococcus aureus for priming immunotherapy in triple-negative breast cancers

Immunotherapy, specifically immune checkpoint blockade (ICB), has revolutionized the treatment paradigm of triple-negative breast cancers (TNBCs). However, a subset of TNBCs devoid of tumor-infiltrating T cells (TILs) or PD-L1 expression generally has a poor response to immunotherapy. In this study, we aimed to sensitize TNBCs to ICB by harnessing the immunomodulating potential of S. aureus, a breast-resident bacterium. We show that intratumoral injection of spent culture media from S. aureus recruits TILs and suppresses tumor growth in a preclinical TNBC model. We further demonstrate that α-hemolysin (HLA), an S. aureus-produced molecule, increases the levels of CD8+ T cells and PD-L1 expression in tumors, delays tumor growth, and triggers tumor necrosis. Mechanistically, while tumor cells treated with HLA display Gasdermin E (GSDME) cleavage and a cellular phenotype resembling pyroptosis, splenic T cells incubated with HLA lead to selective expansion of CD8+ T cells. Notably, intratumoral HLA injection prior to ICB augments the therapeutic efficacy compared to ICB alone. This study uncovers novel immunomodulatory properties of HLA and suggests that intratumoral administration of HLA could be a potential priming strategy to expand the population of TNBC patients who may respond to ICB.

Identification of immune-related genes in the prognosis of head and neck cancer using a novel prognostic signature model

BACKGROUND

Increasing evidence indicates that the immune response plays a critical role in the development of head and neck cancer (HNC). We aimed to develop an immune-related gene signature and evaluate its prognostic value in patients with HNC.

METHODS

We retrieved an HNC cohort from The Cancer Genome Atlas database and divided the samples into high-risk and low-risk groups based on the median of the immune and stromal scores. We performed Venn and Cox analyses to identify the immune-related DEGs to use in our prognostic model. We evaluated the correlation between the model and immune-cell infiltration and validated the prognostic value of the model by applying it to 2 external HNC cohorts.

RESULTS

We identified 7 DEGs-CCR4, WDFY4, VCAM1, LYZ, VSIG4, XIRP1, and CMKLR1-to use in our prognostic model and validated the model by applying it to 2 external HNC cohorts. We found that risk scores based on the model could reflect the status of the tumor microenvironment and that VSIG4 might be associated with lymph node metastasis in HNC.

CONCLUSIONS

We developed a highly accurate immune-related prognostic 7-gene model in HNC predication, indicating that these 7 genes play critical roles in the tumor microenvironment.

Role of the Microbiota in Skin Neoplasms: New Therapeutic Horizons

The skin and the gut are regularly colonized by a variety of microorganisms capable of interacting with the immune system through their metabolites and influencing the balance between immune tolerance and inflammation. Alterations in the composition and diversity of the skin microbiota have been described in various cutaneous diseases, including skin cancer, and the actual function of the human microbiota in skin carcinogenesis, such as in progression and metastasis, is currently an active area of research. The role of Human Papilloma Virus (HPV) in the pathogenesis of squamous cell carcinoma is well consolidated, especially in chronically immunosuppressed patients. Furthermore, an imbalance between Staphylococcus spp., such as Staphylococcus epidermidis and aureus, has been found to be strongly related to the progression from actinic keratosis to squamous cell carcinoma and differently associated with various stages of the diseases in cutaneous T-cell lymphoma patients. Also, in melanoma patients, differences in microbiota have been related to dissimilar disease course and prognosis and may affect the effectiveness and tolerability of immune checkpoint inhibitors, which currently represent one of the best chances of a cure. From this point of view, acting on microbiota can be considered a possible therapeutic option for patients with advanced skin cancers, even if several issues are still open.