Hypoblast from human pluripotent stem cells regulates epiblast development

Recently, several studies using cultures of human embryos together with single-cell RNA-seq analyses have revealed differences between humans and mice, necessitating the study of human embryos1-8. Despite the importance of human embryology, ethical and legal restrictions have limited post-implantation-stage studies. Thus, recent efforts have focused on developing in vitro self-organizing models using human stem cells9-17. Here, we report genetic and non-genetic approaches to generate authentic hypoblast cells (naive hPSC-derived hypoblast-like cells (nHyCs))-known to give rise to one of the two extraembryonic tissues essential for embryonic development-from naive human pluripotent stem cells (hPSCs). Our nHyCs spontaneously assemble with naive hPSCs to form a three-dimensional bilaminar structure (bilaminoids) with a pro-amniotic-like cavity. In the presence of additional naive hPSC-derived analogues of the second extraembryonic tissue, the trophectoderm, the efficiency of bilaminoid formation increases from 20% to 40%, and the epiblast within the bilaminoids continues to develop in response to trophectoderm-secreted IL-6. Furthermore, we show that bilaminoids robustly recapitulate the patterning of the anterior-posterior axis and the formation of cells reflecting the pregastrula stage, the emergence of which can be shaped by genetically manipulating the DKK1/OTX2 hypoblast-like domain. We have therefore successfully modelled and identified the mechanisms by which the two extraembryonic tissues efficiently guide the stage-specific growth and progression of the epiblast as it establishes the post-implantation landmarks of human embryogenesis.

Evaluation of safety and diagnostic performance for flexible hysteroscopy in 1591 outpatient cases

BACKGROUND

To date, only few large studies are available concerning the safety and diagnostic concordance rates of outpatient flexible hysteroscopy. In our institution, outpatient hysteroscopy has been routinely and educationally applied Kosuke Tsuji to intrauterine lesions; thus, we retrospectively investigated the institution's outpatient flexible hysteroscopy cases.

METHODS

A total of 1591 cases of outpatient flexible hysteroscopy conducted at our institution in 2012-2016 were retrospectively analyzed in terms of their clinical background, complications and diagnostic concordance rates.

RESULTS

A total of 1591 cases included 546 cases of benign tumors (317 endometrial polyps, 168 myomas and 61 endometrial hyperplasia), 361 cases of atypical endometrial hyperplasia, 571 cases of endometrial cancers and 113 cases of other diagnoses. No major complications, including uterine perforation, occurred. However, one patient (0.06%) was diagnosed with septic shock caused by intrauterine infection that required prolonged immunosuppressive drug administration. Meanwhile, 335 patients diagnosed with benign tumors through outpatient flexible hysteroscopy underwent operation, and the diagnostic concordance rate was 74.6% (250 cases). However, this rate included 14 cases (4.2%) diagnosed with malignant tumors postoperatively. In preoperative endometrial cancer cases, the sensitivity and specificity for cervical invasion diagnosis were 39.4 and 90.8%, respectively. In addition, only one patient manifested positive ascites cytology intraoperatively, possibly caused by outpatient hysteroscopy.

CONCLUSIONS

Outpatient flexible hysteroscopy is highly safe, with a slight negligible effect on ascites cytology. However, the diagnosis should be determined by multidisciplinary approaches, as hysteroscopy alone can miss malignancy.

Cowden syndrome complicated by schizophrenia: A first clinical report

Patients with Cowden syndrome exhibit mucocutaneous lesions, hamartomatous polyposis of the gastrointestinal tract, and macrocephaly, often complicated by malignant tumors, such as breast, thyroid, and uterine cancers. Autism spectrum and epilepsy have been known as neuropsychiatric symptoms associated with Cowden syndrome; however, to the best of our knowledge, there is no report on cases complicated by schizophrenia. Here, we report a first case of Cowden syndrome complicated by schizophrenia. A 49-year-old Japanese woman started experiencing auditory hallucinations in her teens. She had left breast cancer at the age of 34 years, and right breast cancer at the age of 37 years, all of which were surgically treated. She was also being treated by oral medications for Hashimoto's disease. On consulting her previous doctor for abnormal uterine bleeding that lasted for a year, she was diagnosed with endometrial cancer. However, immediately before surgery, her auditory hallucinations and paranoid delusions became severe, and she was referred to our hospital for detailed examination and treatment. No abnormalities were found on head MRI, and she was diagnosed with schizophrenia on the basis of neuropsychiatric examination findings. After her psychiatric symptoms were controlled by 2 mg of risperidone, she underwent surgery for endometrial cancer. Although there was no apparent family history, physical findings including macrocephaly and papillomatous skin lesions together with her past medical history of multiple malignant tumors suggested Cowden syndrome. Postoperatively, genetic testing revealed a pathogenic variant c.655C > T; p. Gln219* (NM_000314.4) in PTEN, leading to the confirmation of the diagnosis of Cowden syndrome.

The insulin-PI3K-Rac1 axis contributes to terminal adipocyte differentiation through regulation of actin cytoskeleton dynamics

Adipocyte differentiation is accompanied by a pronounced change in the actin cytoskeleton characterized by the reorganization of filamentous (F)-actin stress fibers into cortical F-actin structures. We previously showed that depolymerization of F-actin stress fibers induced by inactivation of RhoA-ROCK (Rho-associated kinase) signaling acts as a trigger for adipocyte differentiation. The relevance and underlying mechanism of the formation of cortical F-actin structures from depolymerized actin during adipocyte differentiation have remained unclear, however. We have now examined the mechanistic relation between actin dynamics and adipogenic induction. Transient exposure to the actin-depolymerizing agent latrunculin A (LatA) supported the formation of adipocyte-associated cortical actin structures and the completion of terminal adipocyte differentiation in the presence of insulin, whereas long-term exposure to LatA prevented such actin reorganization as well as terminal adipogenesis. Moreover, these effects of insulin were prevented by inhibition of phosphatidylinositol 3-kinase (PI3K)-Rac1 signaling and the actin-related protein 2/3 (Arp2/3) complex which is a critical component of the cortical actin networks. Our findings thus suggest that the insulin-PI3K-Rac1 axis leads to the formation of adipocyte-associated cortical actin structures which is essential for the completion of adipocyte differentiation.

LAMC1 is a prognostic factor and a potential therapeutic target in endometrial cancer

OBJECTIVE

With the emerging significance of genetic profiles in the management of endometrial cancer, the identification of tumor-driving genes with prognostic value is a pressing need. The LAMC1 gene, encoding the laminin subunit gamma 1 (LAMC1) protein, has been reported to be involved in the progression of various malignant tumors. In this study, we aimed to investigate the role of LAMC1 in endometrial cancer and elucidate the underlying mechanism.

METHODS

We evaluated the immunohistochemical expression of LAMC1 in atypical endometrial hyperplasia and endometrial cancer. Within the endometrial cancer cases, we analyzed the association of LAMC1 overexpression with clinicopathological factors and prognosis. Furthermore, to indentify genes influenced by LAMC1 overexpression, we transfected HEC50B and SPAC-S cells with siRNA targeting LAMC1 and conducted microarray gene expression assays.

RESULTS

While none of the atypical endometrial hyperplasia specimens exhibited LAMC1 overexpression, endometrial cancer possessed a significantly higher LAMC1 overexpression rate. LAMC1 overexpression was strongly associated with histological type, lymphovascular space invasion, lymph node metastasis, advanced International Federation of Gynecology and Obstetrics stage, and poor overall survival in endometrial cancer. Gene expression microarray analysis identified 8 genes correlated with tumor progression (LZTFL1, TAPT1, SEL1L, PAQR6, NME7, TMEM109, CCDC58, and ANKRD40) that were commonly influenced in HEC50B and SPAC-S by LAMC1 silencing.

CONCLUSION

LAMC1 overexpression is a potent biomarker for identifying endometrial cancer patients needing aggressive adjuvant therapy. We elucidated 8 candidate genes that may mediate progression of LAMC1 overexpressing cancer. Further investigation of the underlying mechanism should lead to the discovery of new therapeutic targets.

ROCK Inhibition Induces Terminal Adipocyte Differentiation and Suppresses Tumorigenesis in Chemoresistant Osteosarcoma Cells

Tumors comprise heterogeneous cell types including cancer stem cells (CSC), progenitor cells, and differentiated cells. Chemoresistance is a potential cause of relapse and a key characteristic of CSC, but the development of novel therapeutic approaches for targeting these cells has been limited. We previously established osteosarcoma-initiating (OSi) cells by introducing the gene for c-Myc into bone marrow stromal cells of Ink4a/Arf knockout mice. These OSi cells are composed of two distinct clones: highly tumorigenic cells (AX cells), similar to bipotent committed osteochondral progenitor cells, and tripotent cells of low tumorigenicity (AO cells), similar to mesenchymal stem cells. Here we show that depolymerization of the actin cytoskeleton induces terminal adipocyte differentiation and suppresses tumorigenesis in chemoresistant OSi cells. In contrast to AX cells, AO cells were highly resistant to conventional chemotherapeutic agents such as doxorubicin and were thus identified as chemoresistant cells. Inhibition of Rho-associated coiled-coil containing protein kinase (ROCK) elicited terminal adipocyte differentiation in chemoresistant AO cells through negative regulation of the transcriptional coactivator megakaryoblastic leukemia 1 associated with actin depolymerization. The clinically administered ROCK inhibitor fasudil significantly suppressed growth in vitro and tumorigenicity in vivo of chemoresistant AO cells as well as of OSi cells. Our findings thus suggest a new therapeutic strategy based on the induction of trans-terminal differentiation via modulation of actin cytoskeleton dynamics for therapy-resistant osteosarcoma stem cells. SIGNIFICANCE: These findings suggest that induction of trans-terminal differentiation through regulation of actin dynamics is a potential novel therapeutic approach for targeting chemoresistant stem-like tumor cells.

Warburg effect in Gynecologic cancers

Mammalian cells produce energy by oxidative phosphorylation under aerobic conditions. However, in the 1920s, Otto Warburg reported the so-called "Warburg effect" in which cancer cells produce ATP that is biased toward glycolysis rather than mitochondrial oxidative phosphorylation not only in anaerobic environment but also in aerobic environment. Glucose is converted into lactate without going into mitochondria after being metabolized in glycolysis. Compared with oxidative phosphorylation, the glycolysis has a faster ATP production rate but it is very inefficient, resulting in cancer cells consuming a large amount of glucose. Increased glucose metabolism has become a biomarker for cancer cells and has led to the development of positron emission tomography with fluorodeoxyglucose. Till date, the Warburg effect has been an inefficient system for cancer cells with regard to efficient energy production, but since the consumption of oxygen can be suppressed as the tumor grows in mass, it is thought that the Warburg effect is advantageous in this situation wherein the tumor can increase despite the lack of vessels. In addition, an increased lactate by the glycolysis causes acidosis in the microenvironment of tissues, which is thought to damage the surrounding normal tissues and favor the invasion and metastasis of cancer. Thus, Warburg effect is one of the key mechanisms for cancer development and will be the next promising target. In this review, we introduce key players that can be targeted in the Warburg effect and outline the prospects of treatment, targeting the Warburg effect in gynecological cancer.

Current state and outlook for drug repositioning anticipated in the field of ovarian cancer

Ovarian cancer is the seventh most common cancer and the eighth most common cause of cancer mortality in women. Although standard chemotherapy is the established treatment for ovarian cancer, the prognosis remains poor, and it is highly anticipated that new drugs will be developed. New drugs, such as humanized anti-vascular endothelial growth factor monoclonal antibodies and poly ADP-ribose polymerase inhibitors, are expected to improve clinical outcomes of ovarian cancer. However, long-term, costly research is required to develop such new drugs, and soaring national healthcare costs are becoming a concern worldwide. In this social context, drug repositioning, wherein existing drugs are used to develop drugs with new indications for other diseases, has recently gained attention. Because trials have already confirmed the safety in humans and the pharmacokinetics of such drugs, the development period is shorter than the conventional development of a new drug, thereby reducing costs. This review discusses the available basic experimental and clinical data on drugs used for other types of cancer for which drug repositioning is anticipated to repurpose the drug for the treatment of ovarian cancer. These include statins, which are used to treat dyslipidemia; bisphosphonate, which is used to treat osteoporosis; metformin, which is used to treat diabetes; non-steroidal anti-inflammatory drugs; ivermectin, an antiparasitic agent; and itraconazole, an anti-fungal agent. These drugs will play an important role in future drug repositioning strategies for ovarian cancer. Furthermore, drug repositioning is anticipated to extend not only to ovarian cancer treatment but also to ovarian cancer prevention.

Radiation-induced angiosarcoma of the omentum diagnosed by laparoscopy: A case report

Angiosarcoma is a rare malignant tumor with an aggressive clinical course and a poor prognosis. Intraperitoneal angiosarcoma, especially originating from the omentum, is extremely rare. We report a case of radiation-induced angiosarcoma of the omentum that arose in a 38-year-old female seven years after concurrent chemoradiotherapy for cervical cancer. The primary tumor was unknown until diagnostic laparoscopy revealed an unresectable omental mass. Pathological examination revealed high-grade malignant cells positive for endothelial markers. Although the small number of cases limits the consensus on optimal therapy for advanced angiosarcoma, the patient was managed successfully by taxane-based chemotherapy, leading to complete response and consequent complete cytoreductive surgery. Our report is the fifth case of radiation-induced angiosarcoma of the omentum, and all have developed after treatment for gynecologic cancer. Although very rare, this complication should be considered after radiation therapy in cancer treatment, particularly given the increasing importance of this therapy.

New use of microsatellite instability analysis in endometrial cancer

The increasing incidence of obesity and diabetes due to changes in diet, earlier menarche, delayed menopause, late marriage, and declining birth rate have resulted in an increase in the number of endometrial cancer cases over the last few decades. Although surgical therapy is sufficient for early endometrial cancer, there is no effective therapy for patients with advanced and recurrent endometrial cancer. The oncogenic mechanism of endometrial cancer involves microsatellite instability (MSI) caused by dysfunction of DNA mismatch repair genes in 30% of patients. Immune checkpoint inhibitors, including anti-programmed death (PD)-1 and anti-PD-ligand 1 antibodies, are of interest as novel anticancer drugs; however, these drugs are currently expensive, and there is a need to select patients who will benefit from their use. The use of MSI analysis as a predictive biomarker for the therapeutic efficacy of these drugs may be useful for reducing the costs of drug therapy.

Recent advances in the molecular mechanisms of Mayer-Rokitansky-Küster-Hauser syndrome

Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) is a disease caused by congenital absence of the uterus and two-thirds of the upper vagina. The pathogenic mechanism of MRKHS may involve gene abnormalities, and there are various case reports associating MRKHS with the Wnt family member 4 (Wnt4) mutation. Analysis of genes mapped to regions in which deletion and duplication are frequently detected in patients with MRKHS has shown involvement of LIM homeobox 1 (LHX1), HNF1 homeobox B (HNF1B) and T-box 6 (TBX6). In addition, there are case reports of MRKHS caused by chromosomal translocation and epigenetic function may be involved in MRKHS onset. Overexpression of HOXA and overexposure to estrogen may contribute to the onset and regulation of expression by methylation as a pathogenic mechanism. Determination of the molecular basis of MRKHS is in progress, but current treatment only includes vaginal enlargement and vaginoplasty for improved quality of life. Clinical application of uterine transplantation to allow childbearing by MRKHS patients is under investigation and clinical trials are underway around the world.

Carcinoma of the lower uterine segment diagnosed with Lynch syndrome based on MSH6 germline mutation: A case report

Endometrial cancer in the lower uterine segment (LUS) is associated with Lynch syndrome with MLH1 or MSH2 germline mutation. Here, we report a case of carcinoma of the LUS diagnosed with Lynch syndrome based on MSH6 germline mutation in a 46-year-old woman with abnormal vaginal bleeding. She had had rectal cancer at age 39 with a family history of colon cancer (father, 75 years), pancreatic cancer (paternal grandmother, 74 years), and colon cancer (maternal grandmother, 85 years). Magnetic resonance imaging showed a tumor in the LUS. Endometrial biopsy revealed endometrioid adenocarcinoma G1. As her cancer history met the revised Bethesda criteria, we examined microsatellite instability and the result was negative, but loss of the MSH6 expression was detected by immunohistochemistry. Genetic testing revealed deleterious germline mutation of MSH6, which was compatible with Lynch syndrome. To our knowledge, this is the first case of endometrial carcinoma of the LUS with MSH6 germline mutation.

Methylation Analysis of DNA Mismatch Repair Genes Using DNA Derived from the Peripheral Blood of Patients with Endometrial Cancer: Epimutation in Endometrial Carcinogenesis

Germline mutation of DNA mismatch repair (MMR) genes is a cause of Lynch syndrome. Methylation of MutL homolog 1 (MLH1) and MutS homolog 2 (MSH2) has been detected in peripheral blood cells of patients with colorectal cancer. This methylation is referred to as epimutation. Methylation of these genes has not been studied in an unselected series of endometrial cancer cases. Therefore, we examined methylation of MLH1, MSH2, and MSH6 promoter regions of peripheral blood cells in 206 patients with endometrial cancer using a methylation-specific polymerase chain reaction (MSP). Germline mutation of MMR genes, microsatellite instability (MSI), and immunohistochemistry (IHC) were also analyzed in each case with epimutation. MLH1 epimutation was detected in a single patient out of a total of 206 (0.49%)-1 out of 58 (1.72%) with an onset age of less than 50 years. The patient with MLH1 epimutation showed high level MSI (MSI-H), loss of MLH1 expression and had developed endometrial cancer at 46 years old, complicated with colorectal cancer. No case had epimutation of MSH2 or MSH6. The MLH1 epimutation detected in a patient with endometrial cancer may be a cause of endometrial carcinogenesis. This result indicates that it is important to check epimutation in patients with endometrial cancer without a germline mutation of MMR genes.