The ribonuclease domain function is dispensable for SLFN11 to mediate cell fate decision during replication stress response.

The SLFN11 gene participates in cell fate decision following cancer chemotherapy and encodes the N-terminal ribonuclease (RNase) domain and the C-terminal helicase/ATPase domain. How these domains contribute to the chemotherapeutic response remains controversial. Here, we expressed SLFN11 containing mutations in two critical residues required for RNase activity in SLFN11-/- cells. We found that this mutant was still able to suppress DNA damage tolerance, destabilized the stalled replication forks, and perturbed recruitment of the fork protector RAD51. In contrast, we confirmed that the helicase domain was essential to accelerate fork degradation. The fork degradation by the RNase mutant was dependent on both DNA2 and MRE11 nuclease, but not on MRE11's novel interactor FXR1. Collectively, these results supported the view that the RNase domain function is dispensable for SLFN11 to mediate cell fate decision during replication stress response.

Estrogen induces genomic instability in high-risk HPV-infected cervix and promotes the carcinogenesis of cervical adenocarcinoma.

High-risk human papillomavirus (HPV) infection is the major cause of cervical cancer. However, the factors that modulate the process from infection to carcinogenesis are poorly understood. Although cervical cancer is clinically considered an estrogen-independent tumor, the role of estrogen in cervical cancer, particularly cervical adenocarcinoma, remains controversial. In this study, we showed that estrogen/GPR30 signaling induced genomic instability, which leads to carcinogenesis in high-risk HPV-infected endocervical columnar cell lines. The expression of estrogen receptors in a normal cervix was confirmed through immunohistochemical analysis which showed that G protein-coupled receptor 30 (GPR30) was predominantly expressed in endocervical glands and estrogen receptor-α (ERα) was expressed at higher levels in the squamous epithelium than in the cervical gland. E2 increased the proliferation of cervical cell lines, particularly normal endocervical columnar and adenocarcinoma cells via GPR30 rather than ERα, and increased the accumulation of DNA double-strand breaks (DSBs) in high-risk HPV-E6-expressing cells. The increase in DSBs was caused by the impairment of Rad 51 and accumulation of topoisomerase-2-DNA complexes under HPV-E6 expression. In addition, chromosomal aberrations increased in cells with E2-induced DSB accumulation. Collectively, we conclude that E2 exposure in high-risk HPV-infected cervical cells increases DSBs, leading to genomic instability and thus carcinogenesis via GPR30.

Lymphangioleiomyoma of the Uterus and Pelvic Lymph Nodes: A Report of 3 Cases, Including the Potentially Earliest Manifestation of Extrapulmonary Lymphangioleiomyomatosis.

We present 3 cases of extrapulmonary lymphangioleiomyomatosis (LAM) identified incidentally in the uterine corpus and pelvic nodes resected for other reasons. One patient, a 47-yr-old female with corpus cancer, underwent a total hysterectomy and nodal dissection; the other 2 patients, aged 44 and 49 yr, underwent simple hysterectomy for corpus leiomyomas. None of the patients had evidence of tuberous sclerosis complex or any significant lesions in other organs. An area of spindle cell proliferation, intimately associated with dilated and tortuous lymphatic vessels, was found in the myometrium of all 3 patients, and nodal involvement with spindle cell proliferation was observed in the patient with corpus cancer. The spindle cells had faintly eosinophilic cytoplasm and a bland appearance. They were immunoreactive for α-SMA, gp100 (HMB45), and Melan-A. Tumor cell clusters lined with a single layer of lymphatic endothelium were floating in the lymphatic vessel lumen. These lesions were diagnosed as lymphangioleiomyoma in the uterine corpus and associated lymph nodes. Two of the cases seemed to be the earliest manifestations of extrapulmonary LAM, and the other case represents early-phase metastasis of LAM from the uterus. The present cases support the speculation that the uterus is the primary source of LAM cells.

Mouse Slfn8 and Slfn9 genes complement human cells lacking SLFN11 during the replication stress response.

The Schlafen (SLFN)11 gene has been implicated in various biological processes such as suppression of HIV replication, replication stress response, and sensitization of cancer cells to chemotherapy. Due to the rapid diversification of the SLFN family members, it remains uncertain whether a direct ortholog of human SLFN11 exists in mice. Here we show that mSLFN8/9 and hSLFN11 were rapidly recruited to microlaser-irradiated DNA damage tracks. Furthermore, Slfn8/9 expression could complement SLFN11 loss in human SLFN11-/- cells, and as a result, reduced the growth rate to wild-type levels and partially restored sensitivity to DNA-damaging agents. In addition, both Slfn8/9 and SLFN11 expression accelerated stalled fork degradation and decreased RPA and RAD51 foci numbers after DNA damage. Based on these results, we propose that mouse Slfn8 and Slfn9 genes may share an orthologous function with human SLFN11. This notion may facilitate understanding of SLFN11's biological role through in vivo studies via mouse modeling.

Endometrial galectin-3 causes endometriosis by supporting eutopic endometrial cell survival and engraftment in the peritoneal cavity.

PROBLEM: The pathogenesis of endometriosis remains unclear. Endometrial cells in retrograde menstruation are considered the source of endometriosis; therefore, we hypothesized that the eutopic endometrium may provide clues regarding the pathogenesis. We aimed to clarify the role of eutopic endometrial cells in endometriosis development. METHOD OF STUDY: Eutopic endometrial tissues were obtained from patients with or without endometriosis, and expression of cell surface molecules in eutopic endometrial stromal cells (ESCs) was evaluated via iTRAQ-based proteomic analysis. Based on the results, we focused on galectin-3. Galectin-3 expression in clinical samples was confirmed by immunohistochemistry and Western blot analysis. The concentration of secreted galectin-3 was measured using enzyme-linked immunosorbent assays. Adhesion and migration of ESCs were evaluated by in vitro adhesion and wound healing assays. The cytotoxicity of natural killer cells was measured via calcein release assays. Cell proliferation was measured using the CyQUANT Cell Proliferation Assay Kit. RESULTS: iTRAQ analysis revealed that galectin-3 expression was specifically elevated in the ESCs from endometriosis patients. Immunohistochemistry confirmed galectin-3 overexpression in the eutopic endometrium of endometriosis, irrespective of the menstrual phase. Galectin-3 was overexpressed and secreted by the eutopic ESCs from patients with endometriosis compared to that from patients without endometriosis. Galectin-3 expression in ESCs increased adhesion and migration, whereas galectin-3 inhibitors impaired these processes. Galectin-3 reduced the cytotoxicity of natural killer cells toward ESCs, while not affecting cell proliferation. CONCLUSION: Galectin-3 promotes peritoneal engraftment of ESCs due to impaired immune surveillance in the peritoneal cavity and increases ESCs adhesion and migration to the peritoneum.

Mesonephric adenocarcinoma of the uterine corpus with intracystic growth completely confined to the myometrium: a case report and literature review.

BACKGROUND: Mesonephric adenocarcinoma (MA) is a rare tumor believed to arise from mesonephric remnants occurring mostly in the uterine cervix and, to a lesser extent, the corpus. Since the first case report of MA in the corpus in 1995, only 16 cases have been reported in the English literature. A recent report suggested that MA originates in Müllerian tissue and exhibits the mesonephric differentiation phenotype. CASE PRESENTATION: An asymptomatic 61-year-old woman was referred to our hospital because of elevated levels of tumor markers. Imaging revealed an intramural lesion of the uterine corpus exhibiting fluorodeoxyglucose uptake. A total hysterectomy and bilateral salpingo-oophorectomy were performed. The tumor was completely confined to the corpus wall and was composed of an intracystic bulky component and an invasive component in the myometrial layer. The tumor exhibited a variety of growth patterns, including a characteristic tubular pattern with dense eosinophilic secretion reminiscent of the thyroid, as well as a variety of morphologies, such as acinar, papillary, and ductal structures. The structures were immunoreactive for CK7, vimentin, CD10, calretinin, PAX8, and GATA3 and almost completely negative for ER/PgR. CA125 and CA19-9 antigen expression was also detected. CONCLUSION: A case of MA with a unique growth pattern of an intracystic mass within the corpus wall is presented. The histogenesis and differential diagnoses are discussed. The histogenesis of MA is not yet clear. We hypothesize two different pathways involved: 1) direct development from the mesonephric remnants and/or 2) mesonephric transformation of Müllerian adenocarcinoma.