Lipoteichoic acids from Staphylococcus aureus stimulate proliferation of human non-small-cell lung cancer cells in vitro

Marine Antimicrobial Peptide Epinecidin-1 Inhibits Proliferation Induced by Lipoteichoic acid and Causes cell Death in non-small cell lung cancer Cells via Mitochondria Damage

Non-small cell lung cancer (NSCLC) is among the deadliest cancers worldwide. Despite the recent introduction of several new therapeutic approaches for the disease, improvements in overall survival and progression-free survival have been minimal. Conventional treatments for NSCLC include surgery, chemotherapy and radiotherapy. Except for surgery, these treatments can impair a patient's immune system, leaving them susceptible to bacterial infections. As such, Staphylococcus aureus infections are commonly seen in NSCLC patients receiving chemotherapy, and a major constituent of the S. aureus cell surface, lipoteichoic acid (LTA), is thought to stimulate NSCLC cancer cell proliferation. Thus, inhibition of LTA-mediated cell proliferation might be a useful strategy for treating NSCLC. Epinecidin-1 (EPI), a marine antimicrobial peptide, exhibits broad-spectrum antibacterial activity, and it also displays anti-cancer activity in glioblastoma and synovial sarcoma cells. Furthermore, EPI has been shown to inhibit LTA-induced inflammatory responses in murine macrophages. Nevertheless, the anti-cancer and anti-LTA activities of EPI and the underlying mechanisms of these effects have not been fully tested in the context of NSCLC. In the present study, we demonstrate that EPI suppresses LTA-enhanced proliferation of NSCLC cells by neutralizing LTA and blocking its effects on toll-like receptor 2 and interleukin-8. Moreover, we show that EPI induces necrotic cell death via mitochondrial damage, elevated reactive oxygen species levels, and disrupted redox balance. Collectively, our results reveal dual anti-cancer activities of EPI in NSCLC, as the peptide not only directly kills cancer cells but it also blocks LTA-mediated enhancement of cell proliferation.

Mimics of Host Defense Peptides Derived from Dendronized Polylysines for Antibacterial and Anticancer Therapy

Bacteria in tumor microenvironments promote carcinogenesis and trigger complications, suggesting the significance of intervening in bacterial growth in cancer treatment. Here, dendrimer-derived mimics (DMs) of host defense peptides (HDPs) were designed for antibacterial and anticancer therapy, which feature a dendronized polylysine core and polycaprolactone arms. DMs displayed not only remarkable activities against Staphylococcus aureus and human lung cancer cells, but also exceptional selectivity. The membranolytic mechanism revealed by morphology analysis explained their low susceptibility to induce resistance. Further, the optimized DM inhibited tumor growth in the subcutaneous tumor model when administered via intraperitoneal injection and exhibited negligible toxicity to tissues. Overall, we combined the superiority of dendrimers and the mechanism from HDPs to design agents with dual antibacterial and anticancer activities that possess great potential for clinical oncology therapy.

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.

Postbiotics as Adjuvant Therapy in Cancer Care

Postbiotics are defined as a preparation of inanimate microorganisms and/or their components that confers a health benefit to the host. They range from cell wall fragments to metabolites, bacterial lysates, extracellular vesicles, and short-chain fatty acids (SCFAs). Postbiotics may influence carcinogenesis via a variety of mechanisms. They can promote homeostatic immune responses, reduce inflammation, induce selective cytotoxicity against tumor cells, as well as the enabling the control of tumor cell proliferation and enhancing intestinal epithelial barrier function. Therefore, probiotics can serve as an adjunct strategy in anticancer treatment together with chemotherapy and immunotherapy. Up to now, the only relevant postbiotics used as interventions in oncological patients remain vitamin K molecules, with few phase-II and III trials available. In fact, postbiotics' levels are strictly dependent on the gut microbiota's composition, which may vary between individuals and can be altered under different physiological and pathological conditions. Therefore, the lack of consistent clinical evidence supporting postbiotics' efficacy is due to their poor bioavailability, short half-life, and fluctuating levels. Synbiotics, a mixture of prebiotics and probiotics, are expected to have a more homogeneous bioavailability with respect to postbiotics and may have greater potential for future development. In this review, we focus on the role of postbiotics as an adjuvant therapy in cancer treatment.

An in vitro coculture approach to study the interplay between dental pulp cells and Streptococcus mutans

AIM

To develop a new coculture system that allows exposure of dental pulp cells (DPCs) to Streptococcus mutans and dentine matrix proteins (eDMP) to study cellular interactions in dentine caries.

METHODOLOGY

Dental pulp cells and S. mutans were cocultured with or without eDMP for 72 h. Cell proliferation and viability were assessed by cell counting and MTT assays, while bacterial growth and viability were determined by CFU and LIVE/DEAD staining. Glucose catabolism and lactate excretion were measured photometrically as metabolic indicators. To evaluate the inflammatory response, the release of cytokines and growth factors (IL-6, IL-8, TGF-β1, VEGF) was determined by ELISA. Non-parametric statistical analyses were performed to compare all groups and time points (Mann-Whitney U test or Kruskal-Wallis test; α = .05).

RESULTS

While eDMP and especially S. mutans reduced the number and viability of DPCs (p ≤ .0462), neither DPCs nor eDMP affected the growth and viability of S. mutans during coculture (p > .0546). The growth of S. mutans followed a common curve, but the death phase was not reached within 72 h. S. mutans consumed medium glucose in only 30 h, whereas in the absence of S. mutans, cells were able to catabolize glucose throughout 72 h, resulting in the corresponding amount of l-lactate. No change in medium pH was observed. S. mutans induced IL-6 production in DPCs (p ≤ .0011), whereas eDMP had no discernible effect (p > .7509). No significant changes in IL-8 were observed (p > .198). TGF-β1, available from eDMP supplementation, was reduced by DPCs over time. VEGF, on the other hand, was increased in all groups during coculture.

CONCLUSIONS

The results show that the coculture of DPCs and S. mutans is possible without functional impairment. The bacterially induced stimulation of proinflammatory and regenerative cytokines provides a basis for future investigations and the elucidation of molecular biological relationships in pulp defence against caries.

Comprehensive assessment of base excision repair (BER)-related lncRNAs as prognostic and functional biomarkers in lung adenocarcinoma: implications for personalized therapeutics and immunomodulation

BACKGROUND

Lung adenocarcinoma (LUAD) is the most prevalent subtype of lung cancer, and comprehending its molecular mechanisms is pivotal for advancing treatment efficacy. This study aims to explore the prognostic and functional significance of base excision repair (BER)-related long non-coding RNAs (BERLncs) in LUAD.

METHODS

A risk score model for BERLncs was developed using the least absolute shrinkage and selection operator regression and Cox regression analysis. Model validation and prognostic evaluation were performed using Kaplan-Meier and receiver-operating characteristic curve analyses. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were conducted to elucidate the potential biological functions of BERLncs. Comparative analyses were carried out to investigate disparities in tumor mutation burden (TMB), immune infiltration, tumor immune dysfunction and exclusion (TIDE) score, chemosensitivity, and immune checkpoint gene expression between the two risk groups.

RESULTS

A predictive risk score model comprising 19 BERLncs was successfully developed. Patients were divided into high-risk and low-risk groups according to the median risk score. The high-risk subgroup exhibited significantly inferior overall survival. Functional enrichment analysis revealed pathways associated with lung cancer development, notably the neuroactive ligand-receptor interaction pathway. High-risk patients demonstrated elevated TMB, diminished TIDE scores, and an immunosuppressive tumor microenvironment, while low-risk patients displayed potential benefits from immunotherapy. Additionally, the risk model identified potential anticancer agents.

CONCLUSION

The risk score model based on BERLncs shows promise as a prognostic biomarker for LUAD patients, providing valuable insights for clinical decision-making, therapeutic strategies, and understanding of underlying biological mechanisms.

A novel tumor microenvironment-related gene signature with immune features for prognosis of lung squamous cell carcinoma

PURPOSE

Lung squamous cell carcinoma (LUSC) is an aggressive subset of non-small-cell lung cancer (NSCLC). The tumor microenvironment (TME) plays an important role in the development of LUSC. We aim to identify potential therapeutic targets and a TME-related prognostic signature and for LUSC.

METHODS

TME-related genes were obtained from TCGA-LUSC dataset. LUSC samples were clustered by the non-negative matrix clustering algorithm (NMF). The prognostic signature was constructed through univariate Cox regression, multivariate Cox regression, and the least absolute shrinkage and selection operator (LASSO) analyses. Gene set enrichment analysis (GSEA) was carried out to explore the enrichment pathways.

RESULTS

This study constructed a prognostic signature which contained 12 genes: HHIPL2, PLK4, SLC6A4, LSM1, TSLP, P4HA1, AMH, CLDN5, NRTN, CDH2, PTGIS, and STX1A. Patients were classified into high-risk and low-risk groups according to the median risk score of this signature. Compared with low-risk group patients, patients in high-risk group patients had poorer overall survival, which demonstrated this signature was an independent prognostic factor. Besides, correlation analysis and GSEA results revealed that genes of this signature were correlated with immune cells and drug response.

CONCLUSION

Our novel signature based on 12 TME-related genes might be applied as an independent prognostic indicator. Importantly, the signature could be a promising biomarker and accurately predict the prognosis of LUSC patients.

Respiratory Tract Oncobiome in Lung Carcinogenesis: Where Are We Now?

The importance of microbiota in developing and treating diseases, including lung cancer (LC), is becoming increasingly recognized. Studies have shown differences in microorganism populations in the upper and lower respiratory tracts of patients with lung cancer compared to healthy individuals, indicating a link between dysbiosis and lung cancer. However, it is not only important to identify "which bacteria are present" but also to understand "how" they affect lung carcinogenesis. The interactions between the host and lung microbiota are complex, and our knowledge of this relationship is limited. This review presents research findings on the bacterial lung microbiota and discusses the mechanisms by which lung-dwelling microorganisms may directly or indirectly contribute to the development of lung cancer. These mechanisms include influences on the host immune system regulation and the local immune microenvironment, the regulation of oncogenic signaling pathways in epithelial cells (causing cell cycle disorders, mutagenesis, and DNA damage), and lastly, the MAMPs-mediated path involving the effects of bacteriocins, TLRs signaling induction, and TNF release. A better understanding of lung microbiota's role in lung tumor pathology could lead to identifying new diagnostic and therapeutic biomarkers and developing personalized therapeutic management for lung cancer patients.

Postbiotics in oncology: science or science fiction?

The gut microbiome has been increasingly understood to play a critical role in carcinogenesis and cancer disease progression. The most recent research advancements have shown that different tools of microbiota manipulation contribute to gut microbiome-immune-oncology axis modulation, offering exciting opportunities for targeted interventions aimed at improving the efficacy of established anti-cancer therapy. Postbiotics are a new entry among the biotics showing beneficial effects on human health while not requiring living cells to obtain the health effect and therefore not subjected to food safety rules for live microorganisms. Postbiotics are recently defined as the "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host" and have gradually become the focus of the scientific community. Since the beginning of research on this topic, numerous studies about postbiotics have been proven to strengthen the gut barrier, reduce inflammation, and promote antimicrobial activity. However, research on the potential application of cancer therapy is still at the early stages of its efforts to uncover all the secrets surrounding postbiotics. This review aims to increase our understanding of the anti-cancer effect of postbiotics throughout a "bibliographic journey" on the biological activity of their components, including exopolysaccharides, cell wall fragments, tryptophan metabolites, enzymes, bacterial lysates, extracellular vesicles, and short-chain fatty acids, highlighting their perspective as a new supportive therapeutic method of treatment and identifying the literature gaps where further research is needed.

The Molecular Basis and Clinical Consequences of Chronic Inflammation in Prostatic Diseases: Prostatitis, Benign Prostatic Hyperplasia, and Prostate Cancer

Chronic inflammation is now recognized as one of the major risk factors and molecular hallmarks of chronic prostatitis, benign prostatic hyperplasia (BPH), and prostate tumorigenesis. However, the molecular mechanisms by which chronic inflammation signaling contributes to the pathogenesis of these prostate diseases are poorly understood. Previous efforts to therapeutically target the upstream (e.g., TLRs and IL1-Rs) and downstream (e.g., NF-κB subunits and cytokines) inflammatory signaling molecules in people with these conditions have been clinically ambiguous and unsatisfactory, hence fostering the recent paradigm shift towards unraveling and understanding the functional roles and clinical significance of the novel and relatively underexplored inflammatory molecules and pathways that could become potential therapeutic targets in managing prostatic diseases. In this review article, we exclusively discuss the causal and molecular drivers of prostatitis, BPH, and prostate tumorigenesis, as well as the potential impacts of microbiome dysbiosis and chronic inflammation in promoting prostate pathologies. We specifically focus on the importance of some of the underexplored druggable inflammatory molecules, by discussing how their aberrant signaling could promote prostate cancer (PCa) stemness, neuroendocrine differentiation, castration resistance, metabolic reprogramming, and immunosuppression. The potential contribution of the IL1R-TLR-IRAK-NF-κBs signaling molecules and NLR/inflammasomes in prostate pathologies, as well as the prospective benefits of selectively targeting the midstream molecules in the various inflammatory cascades, are also discussed. Though this review concentrates more on PCa, we envision that the information could be applied to other prostate diseases. In conclusion, we have underlined the molecular mechanisms and signaling pathways that may need to be targeted and/or further investigated to better understand the association between chronic inflammation and prostate diseases.

A simple liposome-based bionic bacterium for tumor treatment by re-education of tumor-associated microphages in combination with chemotherapy

Re-education of tumor-associated macrophages (TAMs) into M1-like macrophages (Mφ1) has become one of the aims of tumor immunotherapy. Injection of live bacteria has been applied for this purpose; however, an acute innate immune response might be caused in this progress, and therefore a bacteria-based strategy with great security is needed. In this study, the bacterial walls of Staphylococcus aureus were inserted into the bilayer of liposome to construct liposome-based bionic bacteria (Bio-Bac), and doxorubicin (DOX) was encapsulated to form DOX@Bio-Bac. DOX@Bio-Bac re-educated the THP-1-derived TAMs into Mφ1 in vitro, and subsequently inhibited the migration and invasion of CAL27 cells. In a mouse model of hepatocellular carcinoma with lymphatic metastasis, the re-education of TAMs was proved, and an effective inhibition of tumor growth and metastasis in mice was observed. The liposome-based bionic bacteria constructed in this study provide a new strategy for re-education of TAMs, replacing the bacterial therapy reported previously, and a more effective anti-tumor effect can be obtained by combining the chemotherapy drugs with this bionic bacterium.

Lipopolysaccharide and lipoteichoic acid regulate the PI3K/AKT pathway through osteopontin/integrin β3 to promote malignant progression of non-small cell lung cancer

Background

Lung cancer (LC) is a malignancy with one of the highest mortality rates. Respiratory microbiota is considered to play a key role in the development of LC, but the molecular mechanisms are rarely studied.

Methods

We used lipopolysaccharide (LPS) and lipoteichoic acid (LTA) to study human lung cancer cell lines PC9 and H1299. The gene expression of CXC chemokine ligand (CXCL)1/6, interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). The Cell-Counting Kit 8 (CCK-8) was used to analyze cell proliferation. Transwell assays were performed to analyze cell migration ability. Flow cytometry was used to observe cell apoptosis. Western blot and qRT-PCR were used to analyze the expression of secreted phosphoprotein 1 (SPP1), toll-like receptor (TLR)-2/4, and NLR family pyrin domain containing 3 (NLRP3) to determine the mechanism of LPS + LTA. We evaluated the effect of LPS + LTA on cisplatin sensibility by analyzing cell proliferation, apoptosis, and caspase-3/9 expression levels. We observed the proliferation activity, apoptosis, and migration ability of cells in which SPP1 had been transfected small interfering (si) negative control (NC) and integrin β3 siRNA. Then the mRNA expression level and protein expression of PI3K, AKT, and ERK were analyzed. Finally, the nude mouse tumor transplantation model was conducted to verify.

Results

We studied that in two cell lines, the expression level of inflammatory factors in LPS+LTA group was significantly higher than that in single treatment group (P<0.001). We explored LPS + LTA combined treatment group significantly increased the expression of NLRP3 and genes and proteins. LPS + LTA + Cisplatin group could significantly reduce the inhibitory effect of LPS on cell proliferation (P<0.001), reduce the apoptosis rate (P<0.001) and significantly reduce the expression levels of caspase-3/9 (P<0.001) compared with Cisplatin group. Finally, we verified that LPS and LTA could increase osteopontin (OPN)/integrin β3 expression and activate the PI3K/AKT pathway to promote malignant progression of LC in vitro studies.

Conclusions

This study provides a theoretical basis for further exploration of the influence of lung microbiota on NSCLC and the optimization of LC treatment in the future.

The FnBPA from methicillin-resistant Staphylococcus aureus promoted development of oral squamous cell carcinoma

Background

Oral squamous cell carcinoma (OSCC) is the most common tumor in the oral cavity. Methicillin-resistant Staphylococcus aureus (MRSA) were highly detected in OSCC patients; however, the interactions and mechanisms between drug-resistant bacteria (MRSA) and OSCC are not clear.

Aim

The aim of this study was to investigate the promotion of MRSA on the development of OSCC.

Methods

MRSA and MSSA (methicillin-susceptible) strains were employed to investigate the effect on the proliferation of OSCC in vitro and vivo.

Results

All of the MRSA strains significantly increased the proliferation of OSCC cells and MRSA arrested the cell cycles of OSCC cells in the S phase. MRSA activated the expression of TLR-4, NF-κB and c-fos in OSCC cells. MRSA also promoted the development of squamous cell carcinoma in vivo. The virulence factor fnbpA gene was significantly upregulated in all MRSA strains. By neutralizing FnBPA, the promotions of MRSA on OSCC cell proliferation and development of squamous cell carcinoma were significantly decreased. Meanwhile, the activation of c-fos and NF-κB by MRSA was also significantly decreased by FnBPA antibody.

Conclusion

MRSA promoted development of OSCC, and the FnBPA protein was the critical virulence factor. Targeting virulence factors is a new method to block the interaction between a drug-resistant pathogen and development of tumors.

Bidirectional Functional Effects of Staphylococcus on Carcinogenesis

As a Gram-positive cocci existing in nature, Staphylococcus has a variety of species, such as Staphylococcus aureus and Staphylococcus epidermidis, etc. Growing evidence reveals that Staphylococcus is closely related to the occurrence and development of various cancers. On the one hand, cancer patients are more likely to suffer from bacterial infection and antibiotic-resistant strain infection compared to healthy controls. On the other hand, there exists an association between staphylococcal infection and carcinogenesis. Staphylococcus often plays a pathogenic role and evades the host immune system through surface adhesion molecules, α-hemolysin, PVL (Panton-Valentine leukocidin), SEs (staphylococcal enterotoxins), SpA (staphylococcal protein A), TSST-1 (Toxic shock syndrom toxin-1) and other factors. Staphylococcal nucleases (SNases) are extracellular nucleases that serve as genomic markers for Staphylococcus aureus. Interestingly, a human homologue of SNases, SND1 (staphylococcal nuclease and Tudor domain-containing 1), has been recognized as an oncoprotein. This review is the first to summarize the reported basic and clinical evidence on staphylococci and neoplasms. Investigations on the correlation between Staphylococcus and the occurrence, development, diagnosis and treatment of breast, skin, oral, colon and other cancers, are made from the perspectives of various virulence factors and SND1.

The Lung Microbiota and Lung Cancer: A Growing Relationship

Simple Summary

In the past few years, the microbiota has emerged as a major player in cancer management. The efficacy of chemotherapy or immunotherapy may be influenced by the concomitant use of antibiotics before, during, or shortly after treatment with immune checkpoint inhibitors. Despite this, the mechanism linking the microbiota, host immunity, and malignancies are not clear, and the role of microbiota manipulation and analyses in cancer management is underway. In this manuscript, we discuss the role of the microbiota in the initiation, progression, and treatment outcomes of lung cancer.

Abstract

The lung is home to a dynamic microbial population crucial to modulating immune balance. Interest in the role of the lung microbiota in disease pathogenesis and treatment has exponentially increased. In lung cancer, early studies suggested an important role of dysbiosis in tumor initiation and progression. These results have helped accelerate research into the lung microbiota as a potential diagnostic marker and therapeutic target. Microbiota signatures could represent diagnostic biomarkers of early-stage disease. Lung microbiota research is in its infancy with a limited number of studies and only single-center studies with a significant methodological variation. Large, multicenter longitudinal studies are needed to establish the clinical potential of this exciting field.

Lactobacillus johnsonii enhances the gut barrier integrity via the interaction between GAPDH and the mouse tight junction protein JAM-2

Commensal intestinal microbiota interacts with gut epithelial cells in the host by binding to specific host receptors. Several pattern recognition receptors on the gut that sense conserved microbial-associated molecular patterns have been reported; however, many of the gut receptor molecules involved in bacterial binding have not yet been identified. In this study, commensal intestinal bacteria interacting with mouse gut surface proteins were screened from fecal bacterial samples, to identify novel receptors on the epithelial cells in the mouse gut. Among the screened intestinal lactic acid bacteria, the frequently isolated Lactobacillus johnsonii MG was used for the purification of gut receptor proteins. An approximately 30 kDa protein was purified using affinity resin coupled surface layer proteins isolated from L. johnsonii MG. The purified gut protein was identified as a member of the tight junction protein family, junctional adhesion molecule-2 (JAM-2). As expected, the tight junctions of Caco-2 cells damaged by H₂O₂ were repaired by incubation with L. johnsonii MG. RNA sequence analysis showed significant upregulation of the expression of genes for tight junctions, anti-inflammatory effects, transcriptional regulation, and apoptosis in Caco-2 cells, following L. johnsonii MG treatment. In L. johnsonii MG, the surface layer 40 kDa protein was purified with gut protein-coupled affinity resin and identified as the moonlighting protein glyceraldehyde-3-phosphate dehydrogenase (GAPDH). These results suggest that L. johnsonii MG promotes the barrier function integrity in Caco-2 cells via GAPDH-JAM-2 binding. Here, we propose a promising approach to identify novel gut receptor molecules based on commensal bacterial interactions and understand host-bacterial communication in a mouse model.

Domain fusion TLR2-4 enhances the autophagy-dependent clearance of Staphylococcus aureus in the genetic engineering goat

Staphylococcus aureus infections pose a potential threat to livestock production and public health. A novel strategy is needed to control S. aureus infections due to its adaptive evolution to antibiotics. Autophagy plays a key role in degrading bacteria for innate immune cells. In order to promote S. aureus clearance via Toll-like receptor (TLR)-induced autophagy pathway, the domain fusion TLR2-4 with the extracellular domain of TLR2, specific recognizing S. aureus, and transmembrane and intracellular domains of TLR4 is assembled, then the goat expressing TLR2-4 is generated. TLR2-4 substantially augments the removal of S. aureus within macrophages by elevating autophagy level. Phosphorylated JNK and ERK1/2 promote LC3-puncta in TLR2-4 macrophages during S. aureus-induced autophagy via MyD88 mediated the TAK1 signaling cascade. Meantime, the TRIF-dependent TBK1-TFEB-OPTN signaling is involved in TLR2-4-triggered autophagy after S. aureus challenge. Moreover, the transcript of ATG5 and ATG12 is significantly increased via cAMP-PKA-NF-κB signaling, which facilitates S. aureus-induced autophagy in TLR2-4 macrophages. Overall, the novel receptor TLR2-4 enhances the autophagy-dependent clearance of S. aureus in macrophages via TAK1/TBK1-JNK/ERK, TBK1-TFEB-OPTN, and cAMP-PKA-NF-κB-ATGs signaling pathways, which provide an alternative approach for resistant against S. aureus infection.

Secreted Toxins From Staphylococcus aureus Strains Isolated From Keratinocyte Skin Cancers Mediate Pro-tumorigenic Inflammatory Responses in the Skin

Squamous cell carcinoma (SCC) is a common type of skin cancer that typically arises from premalignant precursor lesions named actinic keratoses (AK). Chronic inflammation is a well-known promoter of skin cancer progression. AK and SCC have been associated with an overabundance of the bacterium Staphylococcus aureus (S. aureus). Certain secreted products from S. aureus are known to promote cutaneous pro-inflammatory responses; however, not all S. aureus strains produce these. As inflammation plays a key role in SCC development, we investigated the pro-inflammatory potential and toxin secretion profiles of skin-cancer associated S. aureus. Sterile culture supernatants (“secretomes”) of S. aureus clinical strains isolated from AK and SCC were applied to human keratinocytes in vitro. Some S. aureus secretomes induced keratinocytes to overexpress inflammatory mediators that have been linked to skin carcinogenesis, including IL-6, IL-8, and TNFα. A large phenotypic variation between the tested clinical strains was observed. Strains that are highly pro-inflammatory in vitro also caused more pronounced skin inflammation in mice. Proteomic characterization of S. aureus secretomes using mass spectrometry established that specific S. aureus enzymes and cytolytic toxins, including hemolysins, phenol-soluble modulins, and serine proteases, as well as currently uncharacterized proteins, correlate with the pro-inflammatory S. aureus phenotype. This study is the first to describe the toxin secretion profiles of AK and SCC-associated S. aureus, and their potential to induce a pro-inflammatory environment in the skin. Further studies are needed to establish whether these S. aureus products promote SCC development by mediating chronic inflammation.

Design and optimisation of a small-molecule TLR2/4 antagonist for anti-tumour therapy

In anti-tumour therapy, the toll-like receptor 2/4 (TLR2/4) signalling pathway has been a double-edged sword. TLR2/4 agonists are commonly considered adjuvants for immune stimulation, whereas TLR2/4 antagonists demonstrate more feasibility for anti-tumour therapy under specific chronic inflammatory situations. In individuals with cancer retaliatory proliferation and metastasis after surgery, blocking the TLR2/4 signalling pathway may produce favourable prognosis for patients. Therefore, here, we developed a small-molecule co-inhibitor that targets the TLR2/4 signalling pathway. After high-throughput screening of a compound library containing 14 400 small molecules, followed by hit-to-lead structural optimisation, we finally obtained the compound TX-33, which has effective inhibitory properties against the TLR2/4 signalling pathways. This compound was found to significantly inhibit multiple pro-inflammatory cytokines released by RAW264.7 cells. This was followed by TX-33 demonstrating promising efficacy in subsequent anti-tumour experiments. The current results provide a novel understanding of the role of TLR2/4 in cancer and a novel strategy for anti-tumour therapy.

Bacterial Antigens Reduced the Inhibition Effect of Capsaicin on Cal 27 Oral Cancer Cell Proliferation

Oral cancer is a major global health problem with high incidence and low survival rates. The oral cavity contains biofilms as dental plaques that harbour both Gram-negative and Gram-positive bacterial antigens, lipopolysaccharide (LPS) and lipoteichoic acid (LTA), respectively. LPS and LTA are known to stimulate cancer cell growth, and the bioactive phytochemical capsaicin has been reported to reverse this effect. Here, we tested the efficacy of oral cancer chemotherapy treatment with capsaicin in the presence of LPS, LTA or the combination of both antigens. LPS and LTA were administered to Cal 27 oral cancer cells prior to and/or concurrently with capsaicin, and the treatment efficacy was evaluated by measuring cell proliferation and apoptotic cell death. We found that while capsaicin inhibits oral cancer cell proliferation and metabolism (MT Glo assay) and increases cell death (Trypan blue exclusion assay and Caspase 3/7 expression), its anti-cancer effect was significantly reduced on cells that are either primed or exposed to the bacterial antigens. Capsaicin treatment significantly increased oral cancer cells’ suppressor of cytokine signalling 3 gene expression. This increase was reversed in the presence of bacterial antigens during treatment. Our data establish a rationale for clinical consideration of bacterial antigens that may interfere with the treatment efficacy of oral cancer.

Identification of Survival-Associated Gene Signature in Lung Cancer Coexisting With COPD

Background: Chronic obstructive pulmonary disease (COPD) and lung cancer often coexist, which is associated with a worse prognosis. Thousands of biomarkers related to the survival of lung cancer have been investigated. However, those which can predict the survival of lung cancer coexisting with COPD are currently lacking. The present study aimed to identify novel gene signatures to predict the survival of patients with lung cancer coexisting COPD.

Method: RNA-sequence data of lung cancer and control accompanying with matched clinical information were retrieved from the Cancer Genome Atlas (TCGA). Differently expressed genes (DEGs) associated with lung cancer coexisting COPD were screened. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed. Univariate and multivariate Cox regression analyses were applied to identify survival-associated DEGs and to construct survival-associated gene signature. Kaplan-Meier survival analysis and calibration plots of the nomogram were performed to test the predictive accuracy of the gene signature. qPCR was performed to validate the genes in the prognostic signature.

Results: Sequence data from 70 patients with lung cancer coexisting COPD, 127 with lung cancer alone and 108 control tissues were included for analysis. A total of 2424 DEGs were identified when comparing lung cancer coexisting COPD with controls. The biological process was primarily associated with DNA-binding transcription activator activity, peptidase inhibitor activity, endopeptidase inhibitor activity, et al. KEGG pathways were mainly enriched in neuroactive ligand-receptor interaction, cell cycle, and Staphylococcus aureus infection. A survival-associated gene signature consisting of CEACAM5, RASAL1, CSTL1, CNGB1, and SLC4A3 was identified and represented as risk score. The high-risk score group had significantly worse survival than the low-risk score group (P < 0.001). Areas under receiver operating characteristic curves were 0.943, 0.773, 0.888 for predicting overall survival at 1-, 3-, and 5-year, respectively. The risk score was an independent predictor of survival, independent of clinical factors. High conformity of the actual survival and the nomogram–predicted probability of survival by applying the risk score. Upregulation of the five genes in patients with lung cancer coexisting COPD were confirmed by qPCR in an independent cohort.

Conclusion: Our study constructed and validated a novel prognostic gene signature for predicting survival of patient with lung cancer coexisting COPD, which may contribute to the clinical treatment decisions.

Combined targeting of vascular endothelial growth factor C (VEGFC) and P65 using miR-27b-3p agomir and lipoteichoic acid in the treatment of gastric cancer

Background

Gastric cancer is the second leading cancer-related mortality worldwide and more effective treatment strategies are urgently needed to combat the disease. Using lipoteichoic acid (LTA) and miR-27b-3p agomir, we aimed to assess the efficacy of this combination of therapies in treating gastric cancer.

Methods

The RNA levels of miR-27b-3p, FOXO3, MET, KRAS, vascular endothelial growth factor C (VEGFC), TSC1, and P65 were analyzed by quantified-PCR (Q-PCR) and the cell viability of AGS cells was analyzed by MTT. Confirm Luciferase reporter assays were used to explore the putative miR-27b-3p binding sites and Western blot analyzed the protein level of GAPDH, VEGFC, P65, AKT, and phosphorylated-AKT (p-AKT). The level of P65 in both the cytoplasm and nucleus of AGS cells was visualized by immunofluorescence assay. Subcutaneous xenograft models of gastric cancer were established, and mice were treated with miR-27b-3p agomir, LTA, or both. Hematoxylin-eosin staining and Ki-67 immunohistochemistry analysis of tumor tissues were then performed.

Results

The results showed that the decreased expression of miR-27b-3p in gastric cancer cell lines inhibited the viability of AGS cells, and VEGFC was confirmed as the target of miR-27b-3p. In addition, ectopic expression of miR-27b-3p significantly inhibited the AKT pathway in AGS and N87 cells, and LTA suppressed the proliferation of gastric cancer cells by inhibiting the NF-κB pathway. In an established xenograft model, both miR-27b-3p agomir alone and LTA treatment alone inhibited tumor growth and treatment which combined the two showed an even stronger inhibitory effect.

Conclusions

Taken together, the combined use of LTA and miR-27b-3p agomir exhibited a synergistic effect in the treatment of gastric cancer.

Bacteria Residing at Root Canals Can Induce Cell Proliferation and Alter the Mechanical Properties of Gingival and Cancer Cells

Understanding the importance of oral microbiota in human health and disease also leads to an expansion of the knowledge on functional, metabolic, and molecular alterations directly contributing to oral and systemic pathologies. To date, a compelling number of studies have documented the crucial role of some oral cavity-occurring microbes in the initiation and progression of cancers. Although this effect was noted primarily for Fusobacterium spp., the potential impact of other oral microbes is also worthy of investigation. In this study, we aimed to assess the effect of Enterococcus faecalis, Actinomyces odontolyticus, and Propionibacterium acnes on the proliferation capability and mechanical features of gingival cells and cell lines derived from lung, breast, and ovarian cancers. For this purpose, we incubated selected cell lines with heat-inactivated bacteria and supernatants collected from biofilms, cultured in both anaerobic and aerobic conditions, in the presence of surgically removed teeth and human saliva. The effect of oral bacteria on cell population growth is variable, with the highest growth-promoting abilities observed for E. faecalis in relation to human primary gingival fibroblasts (HGF) and lung cancer A549 cells, and P. acnes in relation to breast cancer MCF-7 and ovarian cancer SKOV-3 cells. Notably, this effect seems to depend on a delicate balance between the pro-stimulatory and toxic effects of bacterial-derived products. Regardless of the diverse effect of bacterial products on cellular proliferation capability, we observed significant alterations in stiffness of gingival and lung cancer cells stimulated with E. faecalis bacteria and corresponding biofilm supernatants, suggesting a novel molecular mechanism involved in the pathogenesis of diseases in oral cavities and tooth tissues. Accordingly, it is proposed that analysis of cancerogenic features of oral cavity bacteria should be multivariable and should include investigation of potential alterations in cell mechanical properties. These findings corroborate the important role of oral hygiene and root canal treatment to assure the healthy stage of oral microbiota.

Identification of potential key genes and key pathways related to clear cell renal cell carcinoma through bioinformatics analysis

Clear cell renal cell carcinoma (ccRCC) is a common malignancy of the genitourinary system and is associated with high mortality rates. However, the molecular mechanism of ccRCC pathogenesis is still unclear, which translates to few effective diagnostic and prognostic biomarkers. In this study, we conducted a bioinformatics analysis on three Gene Expression Omnibus datasets and identified 437 differentially expressed genes (DEGs) related to ccRCC development and prognosis, of which 311 and 126 genes are respectively down-regulated and up-regulated. The protein-protein interaction network of these DEGs consists of 395 nodes and 1872 interactions and 2 prominent modules. The Staphylococcus aureus infection and complement and coagulation cascades are significantly enriched in module 1 and are likely involved in ccRCC progression. Forty-two hub genes were screened, of which von Willebrand factor, TIMP metallopeptidase inhibitor 1, plasminogen, formimidoyltransferase cyclodeaminase, solute carrier family 34 member 1, hydroxyacid oxidase 2, alanine-glyoxylate aminotransferase 2, phosphoenolpyruvate carboxykinase 1, and 3-hydroxy-3-methylglutaryl-CoA synthase 2 are possibly related to the prognosis of ccRCC. The differential expression of all nine genes was confirmed by quantitative real-time polymerase chain reaction analysis of the ccRCC and normal renal tissues. These key genes are potential biomarkers for the diagnosis and prognosis of ccRCC and warrant further investigation.

Identification and validation of tumor microenvironment-related genes of prognostic value in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is a major subtype of non-small cell lung cancer. Despite significant progress in its diagnosis and treatment, the mortality and morbidity rate of LUAD remains high worldwide. The aim of the present study was to perform a systematic investigation of the tumor microenvironment (TME) and identify TME-related genes of prognostic value in patients with LUAD. Firstly, the immune scores and stromal scores of patients with LUAD from The Cancer Genome Atlas were calculated using the Estimation of STromal and Immune cells in MAlignant Tumors using Expression data algorithm, and a total of 281 prognostic TME-related genes were identified. Subsequently, functional analysis and protein-protein interaction network analysis revealed that these genes were mainly related to immune response, inflammatory response and chemotaxis. Finally, two independent LUAD cohorts from the Gene Expression Omnibus database were used to validate these genes, and 4 genes (GTPase IMAP family member 1, T-cell surface glycoprotein CD1b, integrin alpha-L and leukocyte surface antigen CD53) were identified, and downregulation of these genes was indicated to be associated with poor overall survival rate in patients with LUAD. In conclusion, a comprehensive analysis of TME was performed and 4 prognostic TME-related genes in patients with LUAD were identified.

Expression of TLR-2 in hepatocellular carcinoma is associated with tumour proliferation, angiogenesis and Caspase-3 expression

AIMS

Unlike other Toll-like receptors (TLRs), the role of toll like receptor 2 (TLR-2) in the pathogenesis of chronic liver disease and hepatocellular carcinoma (HCC) is not well studied. We, therefore, set out to investigate the expression of TLR-2 in different chronic liver disease states along with other markers of cell death, cellular proliferation and tissue vascularisation METHODS AND RESULTS: Immunohistochemistry was performed on liver tissue microarrays comprising hepatitis, cirrhosis and HCC patient samples using antibodies against TLR-2, Ki-67, Caspase-3 and VEGF. This was done in order to characterise receptor expression and translocation, apoptosis, cell proliferation and vascularisation. Cytoplasmic TLR-2 expression was found to be weak in 5/8 normal liver cases, 10/19 hepatitis cases and 8/21 cirrhosis patients. Moderate to strong TLR-2 expression was observed in some cases of hepatitis and cirrhosis. Both, nuclear and cytoplasmic TLR-2 expression was present in HCC with weak intensity in 11/41 cases, and moderate to strong staining in 19/41 cases. Eleven HCC cases were TLR-2 negative. Surprisingly, both cytoplasmic and nuclear TLR-2 expression in HCC were found to significantly correlate with proliferative index (r = 0.24 and 0.37), Caspase-3 expression (r = 0.27 and 0.38) and vascularisation (r = 0.56 and 0.23). Further, nuclear TLR-2 localisation was predominant in HCC, whereas cytoplasmic expression was more prevalent in hepatitis and cirrhosis. Functionally, treatment of HUH7 HCC cells with a TLR-2 agonist induced the expression of cellular proliferation and vascularisation markers CD34 and VEGF.

CONCLUSIONS

Our results demonstrate a positive correlation between the expression of TLR-2 and other markers of proliferation and vascularisation in HCC which suggests a possible role for TLR-2 in HCC pathogenesis.

Tet38 of Staphylococcus aureus Binds to Host Cell Receptor Complex CD36-Toll-Like Receptor 2 and Protects from Teichoic Acid Synthesis Inhibitors Tunicamycin and Congo Red

Using an affinity column retention assay, we showed that the purified Tet38 membrane transporter of Staphylococcus aureus bound specifically to host cell CD36 and to the complex CD36-Toll-like receptor 2 (TLR-2), but not to TLR-2 alone or TLR-2 and S. aureus lipoteichoic acid (LTA). We tested the effect of LTA on the internalization of S. aureus tet38 mutant QT7 versus RN6390 by A549 epithelial cells. Addition of anti-LTA antibody to the bacteria prior to adding to A549 cells reduced internalization of QT7 2-fold compared to that with nonspecific antibody treatment. QT7 internalized 4- to 6-fold less than RN6390 with or without anti-LTA antibody. These data suggested that Tet38 and LTA were independently involved in the invasion process. The wall teichoic acid (WTA) inhibitor tunicamycin had an 8-fold decrease in activity with overexpression of tet38 and a 2-fold increase in activity in QT7 (tet38). Reserpine (an inhibitor of efflux pumps) reduced the effect of tet38 overexpression on tunicamycin resistance 4-fold. In addition, tet38 affected growth in the presence of LTA inhibitor Congo red, with overexpression increasing growth and deletion of tet38 reducing growth. In conclusion, Tet38 contributes to S. aureus invasion of A549 via direct binding to CD36 of the complex CD36-TLR-2, and LTA independently bound to TLR-2. The reduction of tunicamycin resistance in the presence of reserpine and the survival ability of the tet38 overexpressor in the presence of Congo red suggest that Tet38 can also protect the synthesis of LTA and WTA in S. aureus against their inhibitors, possibly functioning as an efflux pump.

IL-8 regulates the stemness properties of cancer stem cells in the small-cell lung cancer cell line H446

PURPOSE

Cancer stem cells (CSCs) are a small population of cancer cells located within a tumor that are highly tumorigenic, capable of tumor initiation, and resistant to cancer therapies. We identified the potential genes involved in regulating stemness properties and investigated the mechanisms in small-cell lung cancer (SCLC).

MATERIALS AND METHODS

Whole transcriptome sequencing technology was used to screen the potential genes involved in regulating stemness properties from SCLC-SCs (uPAR+) and differentiated cells (uPAR-) in the H446 cell line. The selected genes were validated by quantitative reverse transcription PCR and ELISAs. The effect of IL-8 on stemness of sphere-forming cells was determined through tumor sphere formation, wound healing migration, and in vivo tumorigenesis assays.

RESULTS

In our study, uPAR+ and uPAR- cells showed different gene expression profiles. IL-8 was upregulated in SCLC sphere-forming cells. Blocking IL-8 expression with siRNA led to loss of stemness, including the self-renewal capability, migration, expression of stemness-related genes, and in vivo tumorigenicity, in sphere-forming cells. Consistently, exogenously added IL-8 enhanced stemness properties in parental cells.

CONCLUSION

IL-8 was upregulated in SCLC sphere-forming cells, and critical for the acquisition and/or maintenance of the stemness features in the SCLC cell line H446. Our results suggest that blocking IL-8 signaling may provide a novel therapeutic approach for targeting SCLC-SCs and improve treatment and outcomes in SCLC.

Targeting CREB-binding protein overrides LPS induced radioresistance in non-small cell lung cancer cell lines

Non-small cell lung cancer (NSCLC) has a very poor prognosis even when treated with the best therapies available today often including radiation. NSCLC is frequently complicated by pulmonary infections which appear to impair prognosis as well as therapy, whereby the underlying mechanisms are still not known. It was investigated here, whether the bacterial lipopolysaccharides (LPS) might alter the tumor cell radiosensitivity. LPS were found to induce a radioresistance but solely in cells with an active TLR-4 pathway. Proteome profiling array revealed that LPS combined with irradiation resulted in a strong phosphorylation of cAMP response element-binding protein (CREB). Inhibition of CREB binding protein (CBP) by the specific inhibitor ICG-001 not only abrogated the LPS-induced radioresistance but even led to an increase in radiosensitivity. The sensitization caused by ICG-001 could be attributed to a reduction of DNA double-strand break (DSB) repair.

It is shown that in NSCLC cells LPS leads to a CREB dependent radioresistance which is, however, reversible through CBP inhibition by the specific inhibitor ICG-001. These findings indicate that the combined treatment with radiation and CBP inhibition may improve survival of NSCLC patients suffering from pulmonary infections.

Bioinformatic identification of key genes and analysis of prognostic values in clear cell renal cell carcinoma

The present study aimed to identify new key genes as potential biomarkers for the diagnosis, prognosis or targeted therapy of clear cell renal cell carcinoma (ccRCC). Three expression profiles (GSE36895, GSE46699 and GSE71963) were collected from Gene Expression Omnibus. GEO2R was used to identify differentially expressed genes (DEGs) in ccRCC tissues and normal samples. The Database for Annotation, Visualization and Integrated Discovery was utilized for functional and pathway enrichment analysis. STRING v10.5 and Molecular Complex Detection were used for protein-protein interaction (PPI) network construction and module analysis, respectively. Regulation network analyses were performed with the WebGestal tool. UALCAN web-portal was used for expression validation and survival analysis of hub genes in ccRCC patients from The Cancer Genome Atlas (TCGA). A total of 65 up- and 164 downregulated genes were identified as DEGs. DEGs were enriched with functional terms and pathways compactly related to ccRCC pathogenesis. Seventeen hub genes and one significant module were filtered out and selected from the PPI network. The differential expression of hub genes was verified in TCGA patients. Kaplan-Meier plot showed that high mRNA expression of enolase 2 (ENO2) was associated with short overall survival in ccRCC patients (P=0.023). High mRNA expression of cyclin D1 (CCND1) (P<0.001), fms related tyrosine kinase 1 (FLT1) (P=0.004), plasminogen (PLG) (P<0.001) and von Willebrand factor (VWF) (P=0.008) appeared to serve as favorable factors in survival. These findings indicate that the DEGs may be key genes in ccRCC pathogenesis and five genes, including ENO2, CCND1, PLT1, PLG and VWF, may serve as potential prognostic biomarkers in ccRCC.

Roles of toll-like receptors: From inflammation to lung cancer progression

Lung cancer is among the most common malignant tumors worldwide, and is characterized by a low survival rate compared with other cancers. Toll-like receptors (TLRs) are highly conserved in evolution and widely expressed on immune cells, where they serve an important role in the innate immune system by evoking inflammatory responses. Evasion of immune destruction is an important hallmark in the development of cancer. There is an established association between chronic inflammation and cancer, with TLRs serving important roles in the immune response against tumor cells. Recently, TLRs have been identified on tumor cells, where their activation may orchestrate the downstream signaling pathways that serve crucial functions in tumorigenesis and tumor progression. The present review summarizes the roles of TLRs as sensors on lung cancer cells that regulate lung cancer progression with regard to cell growth and invasion, angiogenesis and cancer stem cell behavior. This aimed to provide theoretical support for the development of therapies that target TLR signaling pathways for the treatment of lung cancer.