Mycoplasma-associated multidrug resistance of hepatocarcinoma cells requires the interaction of P37 and Annexin A2

Extracellular vesicles of minimalistic Mollicutes as mediators of immune modulation and horizontal gene transfer

Extracellular vesicles (EVs) are central components of bacterial secretomes, including the small, cell wall-less Mollicutes. Although EV release in Mollicutes has been reported, EV proteomic composition and function have not been explored yet. We developed a protocol for isolating EVs of the pathogens Mycoplasma mycoides subsp. capri (Mmc) and Mycoplasma (Mycoplasmopsis) bovis and examined their functionality. Proteomic analysis demonstrated that EVs mirror the proteome of the EV-producing bacteria. EVs exhibited nuclease activity, effectively digesting both circular and linear DNA. Notably, M. bovis EVs elicited immune responses in bovine primary blood cells, like those induced by live M. bovis. Our findings reveal that EVs can carry plasmids and enable their horizontal transfer, known as vesiduction. Specifically, the natural plasmid pKMK1, with an unknown transmission route, was detected in EVs of Mmc 152/93 and the tetM-containing pIVB08 plasmid was associated with EVs released by an Mmc GM12 strain carrying this plasmid. pIVB08 could be transferred via homo- and heterologous vesiduction to Mmc, M. capricolum subsp. capricolum and M. leachii. Vesiduction was impeded by membrane disruption but resisted DNase and Proteinase K treatment, suggesting that EVs protect their cargo. These findings enhance our understanding of Mollicutes EVs, particularly in host interactions and horizontal gene transfer.

Exploring the microbiome-gut-testis axis in testicular germ cell tumors

The microbiome-gut-testis axis has emerged as a significant area of interest in understanding testicular cancer, particularly testicular germ cell tumors (TGCTs), which represent the most common malignancy in young men. The interplay between the gut and testicular microbiomes is hypothesized to influence tumorigenesis and reproductive health, underscoring the complex role of microbial ecosystems in disease pathology. The microbiome-gut-testis axis encompasses complex interactions between the gut microbiome, systemic immune modulation, and the local microenvironment of the testis. Dysbiosis in the gut or testicular microbiomes may contribute to altered immune responses, inflammation, and hormonal imbalances, potentially playing a role in the pathogenesis of TGCTs. Concurrently, seminal microbiomes have been linked to variations in sperm quality, fertility potential, and possibly cancer susceptibility, underscoring the need for further evaluation. This review explores the emerging role of the microbiome-gut-testis axis in the context of testicular cancer, highlighting its implications for disease onset, progression, treatment efficacy, and toxicity. Identifying potential microbial biomarkers, followed by microbiota modulation to restore a balanced microbial community, might offer a novel supportive strategy for improving treatment efficacy in refractory TGCT patients while reducing chemotherapy-induced toxicity. We suggest a better understanding of the association between dysregulated microbial environments and TGCTs emphasizes potential pathways by which the gut microbiome might influence testicular cancer.

Targeting the gut and tumor microbiome in cancer treatment resistance

Therapy resistance represents a significant challenge in oncology, occurring in various therapeutic approaches. Recently, animal models and an increasing set of clinical trials highlight the crucial impact of the gut and tumor microbiome on treatment response. The intestinal microbiome contributes to cancer initiation, progression, and formation of distant metastasis. In addition, tumor-associated microbiota is considered a critical player in influencing tumor microenvironments and regulating local immune processes. Intriguingly, numerous studies have successfully identified pathogens within the gut and tumor microbiome that might be linked to a poor response to different therapeutic modalities. The unfavorable microbial composition with the presence of specific microbes participates in cancer resistance and progression via several mechanisms, including upregulation of oncogenic pathways, macrophage polarization reprogramming, metabolism of chemotherapeutic compounds, autophagy pathway modulation, enhanced DNA damage repair, inactivation of a proapoptotic cascade, and bacterial secretion of extracellular vesicles, promoting the processes in the metastatic cascade. Targeted elimination of specific intratumoral bacteria appears to enhance treatment response. However, broad-spectrum antibiotic pretreatment is mostly connected to reduced efficacy due to gut dysbiosis and lower diversity. Mounting evidence supports the potential of microbiota modulation by probiotics and fecal microbiota transplantation to improve intestinal dysbiosis and increase microbial diversity, leading to enhanced treatment efficacy while mitigating adverse effects. In this context, further research concerning the identification of clinically relevant microbiome signatures followed by microbiota-targeted strategies presents a promising approach to overcoming immunotherapy and chemotherapy resistance in refractory patients, improving their outcomes.

Emerging clinical relevance of microbiome in cancer: promising biomarkers and therapeutic targets

The profound influence of microbiota in cancer initiation and progression has been under the spotlight for years, leading to numerous researches on cancer microbiome entering clinical evaluation. As promising biomarkers and therapeutic targets, the critical involvement of microbiota in cancer clinical practice has been increasingly appreciated. Here, recent progress in this field is reviewed. We describe the potential of tumor-associated microbiota as effective diagnostic and prognostic biomarkers, respectively. In addition, we highlight the relationship between microbiota and the therapeutic efficacy, toxicity, or side effects of commonly utilized treatments for cancer, including chemotherapy, radiotherapy, and immunotherapy. Given that microbial factors influence the cancer treatment outcome, we further summarize some dominating microbial interventions and discuss the hidden risks of these strategies. This review aims to provide an overview of the applications and advancements of microbes in cancer clinical relevance.

Bacterial DnaK reduces the activity of anti-cancer drugs cisplatin and 5FU

BACKGROUND

Chemotherapy is a primary treatment for cancer, but its efficacy is often limited by cancer-associated bacteria (CAB) that impair tumor suppressor functions. Our previous research found that Mycoplasma fermentans DnaK, a chaperone protein, impairs p53 activities, which are essential for most anti-cancer chemotherapeutic responses.

METHODS

To investigate the role of DnaK in chemotherapy, we treated cancer cell lines with M. fermentans DnaK and then with commonly used p53-dependent anti-cancer drugs (cisplatin and 5FU). We evaluated the cells' survival in the presence or absence of a DnaK-binding peptide (ARV-1502). We also validated our findings using primary tumor cells from a novel DnaK knock-in mouse model. To provide a broader context for the clinical significance of these findings, we investigated human primary cancer sequencing datasets from The Cancer Genome Atlas (TCGA). We identified F. nucleatum as a CAB carrying DnaK with an amino acid composition highly similar to M. fermentans DnaK. Therefore, we investigated the effect of F. nucleatum DnaK on the anti-cancer activity of cisplatin and 5FU.

RESULTS

Our results show that both M. fermentans and F. nucleatum DnaKs reduce the effectiveness of cisplatin and 5FU. However, the use of ARV-1502 effectively restored the drugs' anti-cancer efficacy.

CONCLUSIONS

Our findings offer a practical framework for designing and implementing novel personalized anti-cancer strategies by targeting specific bacterial DnaKs in patients with poor response to chemotherapy, underscoring the potential for microbiome-based personalized cancer therapies.

Effects and Eradication of Mycoplasma Contamination on Patient-derived Colorectal Cancer Organoid Cultures

Patient-derived organoids are a useful platform for identification and testing of novel precision oncology approaches. Patient-derived organoids are generated by direct culture of patient samples. However, prior to development into patient-derived organoids, these samples are often processed for clinical use, opening the potential for contamination by Mycoplasma and other microbes. While most microbes can be detected by visual inspection, Mycoplasma can go undetected and have substantial impacts on assay results. Given the increased use of patient-derived organoids, there is a growing need for a standardized protocol to detect and remove Mycoplasma from organoid models. In the current study, we report a procedure for Mycoplasma removal by passaging organoids through mice as patient-derived organoid xenografts. In vivo passage of patient-derived organoids followed by re-establishment was 100% effective at decontaminating colorectal patient-derived organoids (n = 9), based on testing with the Sigma LookOut Mycoplasma PCR Detection Kit. This process can serve as a method to re-establish contaminated patient-derived organoids, which represent precious models to study patient-specific genomic features and treatment responses.

SIGNIFICANCE

Organoids are valuable models of cancer. Mycoplasma contamination can alter organoid drug sensitivity, so there is a need for a standardized protocol to detect and remove Mycoplasma from organoids. We report a simple procedure for removing Mycoplasma from organoids via in vivo passaging through mice followed by re-establishment of organoids.

DnaK Functions as a Moonlighting Protein on the Surface of Mycoplasma hyorhinis Cells

Mycoplasma hyorhinis is a common pathogen of swine and is also associated with various human tumors. It causes systemic inflammation, typically polyserositis and polyarthritis, in some infected pigs. However, the pathogenic mechanism of M. hyorhinis remains unclear. DnaK is a highly conserved protein belonging to the heat-shock protein 70 family of molecular chaperones, which plays important roles as a moonlighting protein in various bacteria. In the present study, we identified the surface exposure of M. hyorhinis DnaK. Two virulent strains expressed more DnaK on their surface than the avirulent strain. Thereafter, the potential moonlighting functions of DnaK were investigated. Recombinant M. hyorhinis DnaK (rMhr-DnaK) was found to be able to adhere to swine PK-15 cells and human NCI-H292 cells. It also bound to four extracellular matrix components-fibronectin, laminin, type IV collagen, and vitronectin-in a dose-dependent manner. ELISA demonstrated an interaction between rMhr-DnaK and plasminogen, which was significantly inhibited by a lysine analog, ε-aminocaproic acid. rMhr-DnaK-bound plasminogen was activated by tissue-type plasminogen activator (tPA), and the addition of rMhr-DnaK significantly enhanced the activation. Finally, a DnaK-specific antibody was detected in the serum of pigs immunized with inactivated vaccines, which indicated good immunogenicity of it. In summary, our findings imply that DnaK is an important multifunctional moonlighting protein in M. hyorhinis and likely participates extensively in the infection and pathogenesis processes of M. hyorhinis.

Keeping It Clean: The Cell Culture Quality Control Experience at the National Center for Advancing Translational Sciences

Quality control monitoring of cell lines utilized in biomedical research is of utmost importance and is critical for the reproducibility of data. Two key pitfalls in tissue culture are 1) cell line authenticity and 2) Mycoplasma contamination. As a collaborative research institute, the National Center for Advancing Translational Sciences (NCATS) receives cell lines from a range of commercial and academic sources, which are adapted for high-throughput screening. Here, we describe the implementation of routine NCATS-wide Mycoplasma testing and short tandem repeat (STR) testing for cell lines. Initial testing identified a >10% Mycoplasma contamination rate. While the implementation of systematic testing has not fully suppressed Mycoplasma contamination rates, clearly defined protocols that include the immediate destruction of contaminated cell lines wherever possible has enabled rapid intervention and removal of compromised cell lines. Data for >2000 cell line samples tested over 3 years, and case studies are provided. STR testing of 186 cell lines with established STR profiles revealed only five misidentified cell lines, all of which were received from external labs. The data collected over the 3 years since implementation of this systematic testing demonstrate the importance of continual vigilance for rapid identification of "problem" cell lines, for ensuring reproducible data in translational science research.

Annexin A2 promotion of hepatocellular carcinoma tumorigenesis via the immune microenvironment

Hepatocellular carcinoma (HCC) is the most common primary liver cancer with a dismal prognosis, especially when diagnosed at advanced stages. Annexin A2 (ANXA2), is found to promote cancer progression and therapeutic resistance. However, the underlining mechanisms of ANXA2 in immune escape of HCC remain poorly understood up to now. Herein, we summarized the molecular function of ANXA2 in HCC and its relationship with prognosis. Furthermore, we tentatively elucidated the underlying mechanism of ANXA2 immune escape of HCC by upregulating the proportion of regulatory T cells and the expression of several inhibitory molecules, and by downregulating the proportion of natural killer cells and dendritic cells and the expression of several inhibitory molecules or effector molecules. We expect a lot of in-depth studies to further reveal the underlying mechanism of ANXA2 in immune escape of HCC in the future.

Mycoplasma Infection Mediates Sensitivity of Multidrug-Resistant Cell Lines to Tiopronin: A Cautionary Tale

We previously reported that some, but not all, multidrug-resistant cells that overexpressed various drug-resistance transporters were collaterally sensitive to tiopronin. In recent follow-up studies, we discovered that sensitivity to tiopronin in the original study was mediated by infection of the cells by a human-specific strain of mycoplasma. These results strongly support the need to constantly monitor cells for mycoplasma infection and keep stored samples of all cells that are used for in vitro studies.

Mycoplasmas are no exception to extracellular vesicles release: Revisiting old concepts

Release of extracellular vesicles (EV) by Gram-negative and positive bacteria is being frequently reported. EV are nano-sized, membrane-derived, non-self-replicating, spherical structures shed into the extracellular environment that could play a role in bacteria-host interactions. Evidence of EV production in bacteria belonging to the class Mollicutes, which are wall-less, is mainly restricted to the genus Acholeplasma and is scanty for the Mycoplasma genus that comprises major human and animal pathogens. Here EV release by six Mycoplasma (sub)species of clinical importance was investigated. EV were obtained under nutritional stress conditions, purified by ultracentrifugation and observed by electron microscopy. The membrane proteins of EV from three different species were further identified by mass spectrometry as a preliminary approach to determining their potential role in host-pathogen interactions. EV were shown to be released by all six (sub)species although their quantities and sizes (30-220 nm) were very variable. EV purification was complicated by the minute size of viable mycoplasmal cells. The proteins of EV-membranes from three (sub)species included major components of host-pathogen interactions, suggesting that EV could contribute to make the host-pathogen interplay more complex. The process behind EV release has yet to be deciphered, although several observations demonstrated their active release from the plasma membrane of living cells. This work shed new light on old concepts of "elementary bodies" and "not-cell bound antigens".