The "infectious" nature of human prostate cancer: a cautionary note

Mycoplasma hominis Causes DNA Damage and Cell Death in Primary Human Keratinocytes

Mycoplasma hominis can be isolated from the human urogenital tract. However, its interaction with the host remains poorly understood. In this study, we aimed to assess the effects of M. hominis infection on primary human keratinocytes (PHKs). Cells were quantified at different phases of the cell cycle. Proteins involved in cell cycle regulation and apoptosis progression were evaluated. The expression of genes encoding proteins that are associated with the DNA damage response and Toll-like receptor pathways was evaluated, and the cytokines involved in inflammatory responses were quantified. A greater number of keratinocytes were observed in the Sub-G0/G1 phase after infection with M. hominis. In the viable keratinocytes, infection resulted in G2/M-phase arrest; GADD45A expression was increased, as was the expression of proteins such as p53, p27, and p21 and others involved in apoptosis regulation and oxidative stress. In infected PHKs, the expression of genes associated with the Toll-like receptor pathways showed a change, and the production of IFN-γ, interleukin (IL) 1β, IL-18, IL-6, and tumour necrosis factor alpha increased. The infection of PHKs by M. hominis causes cellular damage that can affect the cell cycle by activating the response pathways to cellular damage, oxidative stress, and Toll-like receptors. Overall, this response culminated in the reduction of cell proliferation/viability in vitro.

Molecular detection of urogenital mollicutes in patients with invasive malignant prostate tumor

BACKGROUND

The etiology of prostate cancer (PCa) is multiple and complex. Among the causes recently cited are chronic infections engendered by microorganisms that often go unnoticed. A typical illustration of such a case is infection due to mollicutes bacteria. Generally known by their lurking nature, urogenital mollicutes are the most incriminated in PCa. This study was thus carried out in an attempt to establish the presence of these mollicutes by PCR in biopsies of confirmed PCa patients and to evaluate their prevalence.

METHODS

A total of 105 Formalin-Fixed Paraffin-Embedded prostate tissues collected from 50 patients suffering from PCa and 55 with benign prostate hyperplasia were subjected to PCR amplification targeting species-specific genes of 5 urogenital mollicutes species, Mycoplasma genitalium, M. hominis, M. fermentans, Ureaplasma parvum, and U. urealyticum. PCR products were then sequenced to confirm species identification. Results significance was statistically assessed using Chi-square and Odds ratio tests.

RESULTS

PCR amplification showed no positive results for M. genitalium, M. hominis, and M. fermentans in all tested patients. Strikingly, Ureaplasma spp. were detected among 30% (15/50) of PCa patients. Nucleotide sequencing further confirmed the identified ureaplasma species, which were distributed as follows: 7 individuals with only U. parvum, 5 with only U. urealyticum, and 3 co-infection cases. Association of the two ureaplasma species with PCa cases proved statistically significant (P < 0.05), and found to represent a risk factor. Of note, Ureaplasma spp. were mostly identified in patients aged 60 and above with prostatic specific antigen (PSA) level > 4 ng/ml and an invasive malignant prostate tumor (Gleason score 8-10).

CONCLUSIONS

This study uncovered a significant association of Ureaplasma spp. with PCa arguing in favour of their potential involvement in this condition. Yet, this finding, though statistically supported, warrants a thorough investigation at a much larger scale.

Should we be testing for urogenital Mycoplasma hominis, Ureaplasma parvum and Ureaplasma urealyticum in men and women? - a position statement from the European STI Guidelines Editorial Board

At present, we have no evidence that we are doing more good than harm detecting and subsequently treating Mycoplasma hominis, Ureaplasma parvum and Ureaplasma urealyticum colonizations/infections. Consequently, routine testing and treatment of asymptomatic or symptomatic men and women for M. hominis, U. urealyticum and U. parvum are not recommended. Asymptomatic carriage of these bacteria is common, and the majority of individuals do not develop any disease. Although U. urealyticum has been associated with urethritis in men, it is probably not causal unless a high load is present (likely carriage in 40-80% of detected cases). The extensive testing, detection and subsequent antimicrobial treatment of these bacteria performed in some settings may result in the selection of antimicrobial resistance, in these bacteria, 'true' STI agents, as well as in the general microbiota, and substantial economic cost for society and individuals, particularly women. The commercialization of many particularly multiplex PCR assays detecting traditional non-viral STIs together with M. hominis, U. parvum and/or U. urealyticum has worsened this situation. Thus, routine screening of asymptomatic men and women or routine testing of symptomatic individuals for M. hominis, U. urealyticum and U. parvum is not recommended. If testing of men with symptomatic urethritis is undertaken, traditional STI urethritis agents such as Neisseria gonorrhoeae, Chlamydia trachomatis, M. genitalium and, in settings where relevant, Trichomonas vaginalis should be excluded prior to U. urealyticum testing and quantitative species-specific molecular diagnostic tests should be used. Only men with high U. urealyticum load should be considered for treatment; however, appropriate evidence for effective treatment regimens is lacking. In symptomatic women, bacterial vaginosis (BV) should always be tested for and treated if detected.

Genetic Passive Immunization with Adenoviral Vector Expressing Chimeric Nanobody-Fc Molecules as Therapy for Genital Infection Caused by Mycoplasma hominis

Developing pathogen-specific recombinant antibody fragments (especially nanobodies) is a very promising strategy for the treatment of infectious disease. Nanobodies have great potential for gene therapy application due to their single-gene nature. Historically, Mycoplasma hominis has not been considered pathogenic bacteria due to the lack of acute infection and partially due to multiple studies demonstrating high frequency of isolation of M. hominis samples from asymptomatic patients. However, recent studies on the role of latent M. hominis infection in oncologic transformation, especially prostate cancer, and reports that M. hominis infects Trichomonas and confers antibiotic resistance to Trichomonas, have generated new interest in this field. In the present study we have generated specific nanobody against M. hominis (aMh), for which the identified target is the ABC-transporter substrate-binding protein. aMh exhibits specific antibacterial action against M. hominis. In an attempt to improve the therapeutic properties, we have developed the adenoviral vector-based gene therapy approach for passive immunization with nanobodies against M. hominis. For better penetration into the mucous layer of the genital tract, we fused aMh with the Fc-fragment of IgG. Application of this comprehensive approach with a single systemic administration of recombinant adenovirus expressing aMh-Fc demonstrated both prophylactic and therapeutic effects in a mouse model of genital M. hominis infection.

Infections and inflammation in prostate cancer

The frequent observation of both acute and chronic inflammation of unknown stimulus in the adult prostate has motivated a large body of research aimed at identifying potential infectious agents that may elicit prostatic inflammation. The overarching hypothesis is that infection-induced inflammation may be associated with prostate cancer development or progression, as inflammation is known to serve as an "enabling characteristic" of cancer. With recent advances in molecular techniques for microorganism identification, a panoply of microorganisms has been scrutinized in prostate tissues and in relation to prostate carcinogenesis. The aim of this review is to summarize the current literature on the evidence for infectious agents as a contributing factor to prostatic inflammation and prostate cancer, and to highlight recent literature suggesting an infectious etiology to the biogenesis of prostatic corpora amylacea and on the development of mouse models of prostatic infections.

Quantification of Mesenchymal Stem Cells (MSCs) at sites of human prostate cancer

Circulating bone marrow-derived Mesenchymal Stem Cells (BM-MSCs) have an innate tropism for tumor tissue in response to the inflammatory microenvironment present in malignant lesions. The prostate is bombarded by numerous infectious & inflammatory insults over a lifetime. Chronic inflammation is associated with CXCL12, CCL5, and CCL2, which are highly overexpressed in prostate cancer. Among other cell types, these chemoattractant stimuli recruit BM-MSCs to the tumor. MSCs are minimally defined as plastic-adhering cells characterized by the expression of CD90, CD73, and CD105 in the absence of hematopoietic markers, which can differentiate into osteoblasts, chondrocytes, and adipocytes. MSCs are immunoprivileged and have been implicated in tumorigenesis through multiple mechanisms, including promoting proliferation, angiogenesis, and metastasis, in addition to the generation of an immunosuppressive microenvironment. We have demonstrated that MSCs represent 0.01-1.1% of the total cells present in core biopsies from primary human prostatectomies. Importantly, these analyses were performed on samples prior to expansion in tissue culture. MSCs in these prostatectomy samples are FAP-, CD90-, CD73-, and CD105-positive, and CD14-, CD20-, CD34-, CD45-, and HLA-DR-negative. Additionally, like BM-MSCs, these prostate cancer-derived stromal cells (PrCSCs) were shown to differentiate into osteoblasts, adipocytes, & chondrocytes. In contrast to primary prostate cancer-derived epithelial cells, fluorescently-labeled PrCSCs & BM-MSCs were both shown to home to CWR22RH prostate cancer xenografts following IV injection. These studies demonstrate that not only are MSCs present in sites of prostate cancer where they may contribute to carcinogenesis, but these cells may also potentially be used to deliver cytotoxic or imaging agents for therapeutic and/or diagnostic purposes.

Can mycoplasma contribute to formation of prostate cancer?

PURPOSE

To reveal the possible role of mycoplasmas in the etiopathogenesis of prostate cancer.

METHODS

In the study, prostate biopsy was performed on 62 patients with an abnormal digital rectal examination and/or elevated PSA. The patients' age was between 62 and 77 (mean 65.4 years) years. Thirty-one patients had adenocarcinoma of the prostate histopathologically (group 1). From these patients, the specimens were divided into two subgroups as specimens with malignant findings (group 1A) and specimens with benign findings (group 1B). The control group consisted of 31 patients with benign prostatic hyperplasia (group 2). In the specimens, the presence of mycoplasma DNA was investigated by the polymerase chain reaction method.

RESULTS

The mycoplasma DNA was found to be positive in 11 (35.4 %) patients in group 1A and in 4 (12.9 %) patients in group 1B. There was no mycoplasma DNA in the patients in group 2. The differences between group 1A and group 1B, and between group 1A and group 2 were statistically significant (p values, respectively, 0.006 and 0.0001).

CONCLUSIONS

Our data supported the thesis that mycoplasma infections play a role in the etiopathogenesis of the prostate cancer.