Complementary Role of GlcNAc6ST2 and GlcNAc6ST3 in Synthesis of CL40-Reactive Sialylated and Sulfated Glycans in the Mouse Pleural Mesothelium.

Sialyl 6-sulfo Lewis X (6-sulfo sLeX) and its derivative sialyl 6-sulfo N-acetyllactosamine (LacNAc) are sialylated and sulfated glycans of sialomucins found in the high endothelial venules (HEVs) of secondary lymphoid organs. A component of 6-sulfo sLeX present in the core 1-extended O-linked glycans detected by the MECA-79 antibody was previously shown to exist in the lymphoid aggregate vasculature and bronchial mucosa of allergic and asthmatic lungs. The components of 6-sulfo sLeX in pulmonary tissues under physiological conditions remain to be analyzed. The CL40 antibody recognizes 6-sulfo sLeX and sialyl 6-sulfo LacNAc in O-linked and N-linked glycans, with absolute requirements for both GlcNAc-6-sulfation and sialylation. Immunostaining of normal mouse lungs with CL40 was performed and analyzed. The contribution of GlcNAc-6-O-sulfotransferases (GlcNAc6STs) to the synthesis of the CL40 epitope in the lungs was also elucidated. Here, we show that the expression of the CL40 epitope was specifically detected in the mesothelin-positive mesothelium of the pulmonary pleura. Moreover, GlcNAc6ST2 (encoded by Chst4) and GlcNAc6ST3 (encoded by Chst5), but not GlcNAc6ST1 (encoded by Chst2) or GlcNAc6ST4 (encoded by Chst7), are required for the synthesis of CL40-positive glycans in the lung mesothelium. Furthermore, neither GlcNAc6ST2 nor GlcNAc6ST3 is sufficient for in vivo expression of the CL40 epitope in the lung mesothelium, as demonstrated by GlcNAc6ST1/3/4 triple-knock-out and GlcNAc6ST1/2/4 triple-knock-out mice. These results indicate that CL40-positive sialylated and sulfated glycans are abundant in the pleural mesothelium and are synthesized complementarily by GlcNAc6ST2 and GlcNAc6ST3, under physiological conditions in mice.

Calnexin Is Involved in Forskolin-Induced Syncytialization in Cytotrophoblast Model BeWo Cells.

Calnexin (CNX), a membrane-bound molecular chaperone, is involved in protein folding and quality control of nascent glycoproteins in the endoplasmic reticulum. We previously suggested critical roles of calreticulin, a functional paralogue of CNX, in placentation, including invasion of extravillous trophoblasts and syncytialization of cytotrophoblasts. However, the roles of CNX in placentation are unclear. In human choriocarcinoma BeWo cells, which serve as an experimental model of syncytialization, CNX knockdown suppressed forskolin-induced cell fusion and ß-human chorionic gonadotropin (ß-hCG) induction. Cell-surface luteinizing hormone/chorionic gonadotropin receptor, a ß-hCG receptor, was significantly down-regulated in CNX-knockdown cells, which suggested the presence of a dysfunctional autocrine loop of ß-hCG up-regulation. In this study, we also found abundant CNX expression in normal human placentas. Collectively, our results revealed the critical role of CNX in the syncytialization-related signaling in a villous trophoblast model and suggest a link between CNX expression and placenta development.

Cytoplasmic p53 aggregates accumulated in p53-mutated cancer correlate with poor prognosis.

Recent studies suggested that aggregates of mutant p53 proteins may propagate and impair normal p53 functioning in recipient cells. Our previous study showed that cancer cell-derived p53 aggregates that cells internalized interfered with p53-dependent apoptosis in recipient cells. However, involvement of p53 aggregate propagation in cancer pathology has not been fully elucidated. Here, we screened patients with high-grade serous ovarian carcinoma, which is characterized by an extremely high frequency of TP53 gene mutations, to show that patients with cytoplasmic p53 deposits have a poor prognosis compared with patients with complete p53 absence or strong nuclear p53 positivity. Cytoplasmic p53 in the patients with poor prognosis consisted of protein aggregates, which suggests that p53 aggregates are oncogenic drivers. Indeed, an inhibitor of p53 aggregation restored cellular apoptosis, a proper p53 function, in p53 aggregate-bearing patient-derived tumor organoids. In cell-based assays, endogenous and exogenous mutant p53 aggregates hindered chemotherapeutic activity of cisplatin, which depends on normal p53 functions. This inhibition was reduced by blocking p53 aggregation or internalization of p53 aggregates. Our study, thus indicates the involvement of p53 aggregate transmission in poor prognosis and in chemotherapy resistance in cancers.

Low-grade endometrial stromal sarcoma in a young woman diagnosed after resection of endometrial polyp-like lesions: A case report.

Low-grade endometrial stromal sarcoma (LG-ESS) is a rare tumor that mostly occurs in perimenopausal women. Treatment with total hysterectomy and bilateral salpingo-oophorectomy is recommended, although fertility preservation or ovarian preservation may be considered in younger patients. The present study reports a case of LG-ESS in a young woman diagnosed after resection of endometrial polyp-like lesions. A 26-year-old nulligravid woman was referred to our hospital after being diagnosed with endometrial polyps. Hysteroscopic endometrial polypectomy was performed twice, and LG-ESS was suspected on postoperative pathological examination. Magnetic resonance imaging revealed a tumor 5-cm in diameter on the right side of the uterus. In light of the young age of the patient, tumorectomy was first performed, and postoperative pathological diagnosis was LG-ESS with the positive resection margin. After thorough discussion with the patient about fertility preservation and recurrence risk, a total abdominal hysterectomy and ovarian preservation was performed. Medroxyprogesterone therapy was performed postoperatively and no recurrence was observed for 2 years.

Malignant melanoma treated with pembrolizumab during pregnancy: A case report and review of the literature.

There have been very few reports on the use of immune checkpoint inhibitors for malignant tumors during pregnancy. Herein, the current study reports a case of a patient diagnosed with advanced malignant melanoma who was treated with pembrolizumab during pregnancy. A 40-year-old primigravida underwent noninvasive prenatal testing at 10 weeks of gestation, and the result was inconclusive, suggesting the possibility of maternal malignancy. A biopsy of the gluteal mass led to a diagnosis of malignant melanoma, and computed tomography revealed extensive metastases in her lungs and lymph nodes. She had a strong desire to proceed with pregnancy. In consideration of fetal growth and maturation, monotherapy was administered with pembrolizumab from 21 weeks of gestation, aiming for 28 weeks of gestation. The fetus grew well without maternal complications. At 28 weeks of pregnancy, the patient gave birth to a healthy boy by cesarean section. There was no evidence of metastasis in the placenta. The patient received nivolumab-ipilimumab combination therapy from postpartum day 13, followed by nivolumab monotherapy, and has been alive with controlled disease for 20 months.