New insights into pattern recognition receptors and their ligands in gynecologic pathologies

Opportunities and Challenges of the Human Microbiome in Ovarian Cancer

Ovarian cancer is the most lethal malignancy among gynecological cancers worldwide. Most ovarian cancer patients are diagnosed at an advanced stage because of non-specific clinical symptoms. The human microbiome plays a crucial role in maintaining the normal physiological and pathological state of the body. With the development of technologies such as DNA and 16S rRNA sequencing, an increasing number of findings on the role of microbiome in cancers are being reported. Microbiome abnormalities are increasingly associated with diseases, including cancer development, and response to therapies. Some studies have shown the relationship between microbiome changes and ovarian cancer. However, the mechanisms underlying this relationship are not yet fully understood. Here, we summarize the key findings in this regard by focusing on estrogen metabolism and host recognition receptors in microorganisms and changes in the gut or pelvic microbiome in patients with ovarian cancer. We further discuss the potential of using the microbiome as a novel biomarker for cancers. We also highlight the possibility to use microorganisms as a treatment modality to enhance the immune system, activate anti-tumor response, mediate chemotherapy resistance, and ameliorate the adverse effects of the treatment.

Differences in C-type lectin receptors and their adaptor molecules in the peritoneal fluid of patients with endometriosis and gynecologic cancers

Endometriosis, although not malignant, has clinically demonstrated properties of invasiveness and metastasis. The pathogenesis of endometriosis, however, has not yet been elucidated. The immunological differences between endometriosis and malignant gynecologic tumors were analyzed by assessing C-type lectin receptors, which are associated with innate immunity, and immunoglobulin secretion, which is associated with B cell adaptive immunity, in the peritoneal fluid of these patients. Peritoneal fluid samples were obtained from 42 patients with benign masses (control group), 38 with endometriosis, and 43 with gynecologic (ovarian, uterine, and cervical) cancers. The levels of expression in these samples of mRNAs encoding the C-type lectin receptors Dectin-1, MR1, MR2, DC-SIGN, Syk, Card 9, Bcl 10, Malt 1, src, Dec 205, Galectin, Tim 3, Trem 1, and DAP 12, were measured by real-time reverse transcription polymerase chain reaction, and the concentrations of IgG, IgA and IgM were measured by enzyme-linked immunosorbent assays (ELISA). Findings in the three groups were compared. The level of galectin mRNA was significantly lower, and the levels of MR2 and DAP 12 mRNAs significantly higher, in the endometriosis than in the control group (p<0.05 each). Compared with the gynecologic cancer group, the level of Bcl 10 mRNA was significantly lower, and the levels of MR1, MR2, Syk, Card 9, Malt 1, Dec 205, Tim 3, and DAP 12 mRNAs significantly higher, in the endometriosis group (p<0.05 each). The levels of MR2 and DAP 12 mRNAs were significantly higher in the endometriosis than in the control group (p<0.05 each), whereas the level of galectin mRNA was similar in the endometriosis and gynecologic cancer groups. IgA and IgG concentrations in peritoneal fluid were significantly lower in the gynecologic cancer than in the control group (p<0.05 each). However, concentrations of all three immunoglobulins in the endometriosis group did not differ from those in the other two groups (p>0.05). C-type lectin receptors and immunoglobulins act cooperatively and are closely associated in the pathogenesis of endometriosis. The decreased expression of galectin mRNA in the peritoneal fluid of the endometriosis group suggests that endometriosis and gynecologic cancers have similar immunologic characteristics.

Increased expression of pattern recognition receptors and nitric oxide synthase in patients with endometriosis

OBJECTIVE

Endometriosis is characterized by repeated inflammatory changes and serious adhesions, inducing innate and adaptive immune responses within the abdominal cavity. To assess these immune responses, we evaluated the levels of expression of Toll-like receptors (TLR)-1, -2, -4, -5, and -9; nucleotide-binding oligomerization domains (NOD)-1 and -2; interleukins-1β, -6, -8, -10, and -12; interferon-γ; tumor necrosis factor-α; inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS); and immunoglobulins (Igs) in patients with endometriosis.

METHODS

The levels of TLRs, NODs, cytokines, and NOS mRNAs in peritoneal effusions were assessed by real time reverse transcription-polymerase chain reaction; and IgG, IgA and IgM concentrations were measured by enzyme-linked immunosorbent assays (ELISA) in 40 patients with and 40 without endometriosis. Findings from the two groups were compared.

RESULTS

We observed expression of all pattern recognition receptors (PRRs), cytokines, and NOS mRNAs and Igs in the effusion fluid of patients with and without endometriosis. The levels of TLR-2 and -9; NOD-1 and -2; iNOS and eNOS mRNAs and CA 125 were significantly higher in the endometriosis than in the non-endometriosis group (p<0.05 each). Moreover, PRR, cytokine, and NOS expression showed significant correlations (p<0.05).

CONCLUSIONS

PRRs, cytokines, and NOS, which act cooperatively in the innate immune response, are closely associated with endometriosis. Increased expression of TLR-2, TLR -9, NOD-1, NOD-2, and NOS mRNA in peritoneal fluid may be associated with endometriosis.

A potential link of oxidative stress and cell cycle regulation for development of endometriosis

BACKGROUND

The roles of molecular alteration such as genomic instability and cell survival are debated aspects of the pathogenesis of endometriosis. To review the contemporary literature on potential factors and their signaling pathways that support prolonged survival of endometriotic cells.

METHODS

This article reviews the English-language literature for molecular, pathogenetic, and pathophysiological studies on endometriosis. This review is focused on the association of hepatocyte nuclear factor (HNF)-1β with endometriosis.

RESULTS

The iron-induced oxidative stress plays a fundamental role for the pathogenesis of endometriosis. Oxidative stress, secondary to influx of iron during retrograde menstruation, modifies lipids and proteins, leading to cell and DNA damage. Recent studies demonstrated HNF-1β overexpression in endometriotic foci. HNF-1β increases the survival of endometriotic cells under iron-induced oxidative stress conditions possibly through the activation of forkhead box (FOX) transcription factors and/or endometriosis-specific expression of microRNAs. Endometriotic cells expressing HNF-1β also display cell cycle checkpoint pathways required to survive DNA damaging events.

CONCLUSIONS

HNF-1β in endometriosis might be a factor that controls the cell cycle and DNA damage checkpoints.

Molecular mechanisms linking endometriosis under oxidative stress with ovarian tumorigenesis and therapeutic modalities

Inflammation plays a role in the pathogenesis of endometriosis. Endometriosis-associated ovarian carcinogenesis might be promoted through oxidative stress-induced increased genomic instability, aberrant methylation, and aberrant chromatin remodeling, as well as mutations of tumor suppressor genes. Aberrant expression of ARID1A, PIK3CA, and NF-kB genes has been recognized as the major target genes involved in oxidative stress-induced carcinogenesis. HNF-1beta appears to play a key role in anti-oxidative defense mechanisms. We discuss the pathophysiologic roles of oxidative stress as somatic mutations as well as highly specific agents that effectively modulate these targets.

Ovarian epithelial-stromal interactions: role of interleukins 1 and 6

Ovarian epithelial cancer is the most lethal gynecologic malignancy. The high mortality is attributed to the fact that most cases typically present in late stage when ovarian cancer (OC) has already spread beyond the ovary. Ovarian epithelial cancer cells are shed into intraperitoneal ascites and easily disseminate throughout the peritoneal cavity with preferential metastasis to the omentum, peritoneum, and local organs. Understanding how ovarian epithelial cells interact with and modulate their microenvironment can provide insight into the molecular mechanism(s) involved with malignant transformation and progression which may eventually identify novel diagnostic, prognostic, and therapeutic targets. The objective of this paper is to provide a brief consideration of ovarian surface epithelial-stromal interactions in regard to normal physiological function and tumor progression as influenced by two potentially key interleukins, interleukins-1 (IL-1) and -6 (IL-6), present in the microenvironment. Lastly, we will consider the clinical implications of IL-1 and IL-6 for OC patients.