Integrated multi-omics analyses and functional validation reveal TTK as a novel EMT activator for endometrial cancer.

BACKGROUND: Cancer-testis antigens (CTAs) are often expressed in tumor and testicular tissues but not in other normal tissues. To date, there has been no comprehensive study of the expression and clinical significance of CTA genes associated with endometrial cancer (EC) development. Additionally, the clinical relevance, biological role, and molecular mechanisms of the CTA gene TTK protein kinase (TTK) in EC are yet to be fully understood. METHODS: Using bioinformatics methods, we comprehensively investigated the genomic, transcriptomic, and epigenetic changes associated with aberrant TTK overexpression in EC samples from the TCGA database. We further investigated the mechanisms of the lower survival associated with TTK dysregulation using single-cell data of EC samples from the GEO database. Cell functional assays were used to confirm the biological roles of TTK in EC cells. RESULTS: We identified 80 CTA genes that were more abundant in EC than in normal tissues, and high expression of TTK was significantly linked with lower survival in EC patients. Furthermore, ROC analysis revealed that TTK could accurately distinguish stage I EC tissues from benign endometrial samples, suggesting that TTK has the potential to be a biomarker for early EC detection. We found TTK overexpression was more prevalent in EC patients with high-grade, advanced tumors, serous carcinoma, and TP53 alterations. Furthermore, in EC tissue, TTK expression showed a strong positive correlation with EMT-related genes. With single-cell transcriptome data, we identified a proliferative cell subpopulation with high expression of TTK and known epithelial-mesenchymal transition (EMT)-related genes and transcription factors. When proliferative cells were grouped according to TTK expression levels, the overexpressed genes in the TTKhigh group were shown to be functionally involved in the control of chemoresistance. Utilizing shRNA to repress TTK expression in EC cells resulted in substantial decreases in cell proliferation, invasion, EMT, and chemoresistance. Further research identified microRNA-21 (miR-21) as a key downstream regulator of TTK-induced EMT and chemoresistance. Finally, the TTK inhibitor AZ3146 was effective in reducing EC cell growth and invasion and enhancing the apoptosis of EC cells generated by paclitaxel. CONCLUSION: Our findings establish the clinical significance of TTK as a new biomarker for EC and an as-yet-unknown carcinogenic function. This present study proposes that the therapeutic targeting of TTK might provide a viable approach for the treatment of EC.

"Welcome to OBGYN World!" A novel recruitment event for medical students organized by the Japan Society of Obstetrics and Gynecology.

"Welcome to OBGYN World!" A novel recruitment event for medical students organized by the Japan Society of Obstetrics and Gynecology. Since 2012, the number of doctors in Japan who specialize in obstetrics and gynecology has shown a decreasing trend. To increase the number of doctors majoring in obstetrics and gynecology, the Japanese Trainees in Obstetrics and Gynecology subcommittee developed a new recruitment event called Welcome to OBGYN World! (WOW!); the aim of this event was to focus on lower grades of medical students. The present report describes the content of WOW! and the results of a post-event questionnaire administered to participating students and tutors. WOW! was held online in order to avoid the risk of Coronavirus Disease 2019 infection for participants. Sixty of the 82 medical schools nationwide (73.2%) participated in this event. Overall, there were 285 participating students, ranging from first to fourth grade in medical school, and 106 tutors were involved to teach material at the event. In the post-event questionnaire survey, 97.6% (248/254) and 100% of the participants stated they now had a high degree of interest in obstetrics and gynecology and found the specialty attractive, respectively. Furthermore, 93.6% (90/94) of the tutors stated that WOW! had helped recruitment activities in their universities. Based on this outcome, members of the Japanese Trainees of Obstetrics and Gynecology subcommittee will now try to increase the number of doctors specializing in obstetrics and gynecology by holding WOW! annually.

Patterns and predictors of site-specific recurrence in cervical cancer after radical hysterectomy.

AIM: This study examines patterns and predictors of site-specific recurrence to explore the causes of local recurrence of cervical cancer. METHODS: Radical hysterectomy was performed in 121 patients (stage IB-IIB). Nerve-sparing was performed whenever possible. The first recurrence in local, regional, and distant areas was examined. We investigated the possibility of nerve involvement in local recurrence, focusing on paravaginal tissues containing the pelvic plexus. We provide Supporting Information on local recurrence in the paravaginal area. RESULTS: Local recurrence was an independent event from regional or distant recurrence. Local recurrence was seen only in high-risk patients, while regional and distant recurrences were not or less related to the risk category. The independent risk factors by logistic regression for local, regional, and distant recurrence were parametrial invasion, vaginal invasion, and lymph node metastasis, respectively. Local recurrence showed a comparable or more significant negative impact on survival than distant recurrence. Among seven patients with local recurrences, five had a recurrence in the paravagina. The rate of paravaginal recurrence was one in 76 early-stage and four in 45 locally advanced diseases. Four sites of paravaginal recurrence occurred on the nerve-sparing side and two on the non-nerve-sparing side. Supporting Information demonstrated histological evidence of perineural spread into the pelvic plexus and perineural invasion of the primary tumor. CONCLUSIONS: A high percentage of local recurrences are in paravaginal tissue containing the pelvic plexus. The causal association of nerve-sparing surgery and perineural invasion with local recurrence needs to be investigated in large prospective studies.

Long Non-Coding RNA TMPO-AS1 Promotes GLUT1-Mediated Glycolysis and Paclitaxel Resistance in Endometrial Cancer Cells by Interacting With miR-140 and miR-143.

Increased glycolysis in tumor cells is frequently associated with drug resistance. Overexpression of glucose transporter-1 (GLUT1) promotes the Warburg effect and mediates chemoresistance in various cancers. Aberrant GLUT1 expression is considered as an essential early step in the development of endometrial cancer (EC). However, its role in EC glycolysis and chemoresistance and the upstream mechanisms underlying GLUT1 overexpression, remain undefined. Here, we demonstrated that GLUT1 was highly expressed in EC tissues and cell lines and that high GLUT1 expression was associated with poor prognosis in EC patients. Both gain-of-function and loss-of-function studies showed that GLUT1 increased EC cell proliferation, invasion, and glycolysis, while also making them resistant to paclitaxel. The long non-coding RNA TMPO-AS1 was found to be overexpressed in EC tissues and to be negatively associated with EC patient outcomes. RNA-immunoprecipitation and luciferase reporter assays confirmed that TMPO-AS1 elevated GLUT1 expression by directly binding to two critical tumor suppressor microRNAs (miR-140 and miR-143). Downregulation of TMPO-AS1 remarkably reduced EC cell proliferation, invasion, glycolysis, and paclitaxel resistance in EC cells. This study established that dysregulation of the TMPO-AS1-miR-140/miR-143 axis contributes to glycolysis and drug resistance in EC cells by up-regulating GLUT1 expression. Thus, inhibiting TMPO-AS1 and GLUT1 may prove beneficial in overcoming glycolysis-induced paclitaxel resistance in patients with EC.

Paclitaxel-carboplatin and bevacizumab combination with maintenance bevacizumab therapy for metastatic, recurrent, and persistent uterine cervical cancer: An open-label multicenter phase II trial (JGOG1079).

OBJECTIVE: This multicenter, open-label, phase II study aimed to evaluate the efficacy and safety of paclitaxel-carboplatin, bevacizumab, and bevacizumab-based maintenance therapy for metastatic, recurrent, and persistent uterine cervical cancer. METHODS: Patients with measurable diseases that were not adapted to regional therapies, such as surgery or radiotherapy, and were systematic chemotherapy-naïve were eligible. The participants received paclitaxel (175 mg/m2), carboplatin (AUC 5), and bevacizumab (15 mg/m2) every three weeks until disease progression or unacceptable adverse events occurred. The primary endpoint was progression-free survival (PFS). The secondary endpoints were overall response rate (ORR), overall survival (OS), safety, and time to treatment failure. RESULTS: Sixty-nine patients were analyzed using our protocol. The median paclitaxel- carboplatin therapy duration was six cycles; 40% of patients received bevacizumab maintenance therapy. The median PFS was 11.3 months. The median OS was not reached; the median time to treatment failure was 5.9 months. The ORR was 79.7% [95% confidence interval (CI) 63.8-88.4]; 16 patients (23.2%) showed complete response (CR) and 39 patients (56.5%) showed partial response (PR). The median PFS was 14.3 months (95% CI 7.3-17 months) for the 25 patients who received maintenance therapy and 7.4 months (95% CI 6.1-11 months) for nonrecipients (p = 0.0449). Gastrointestinal perforation/fistulas occurred in four patients (5.6%), all of whom had a history of radiation therapy. CONCLUSIONS: Paclitaxel-carboplatin and bevacizumab therapy is an acceptable and tolerable treatment for advanced or recurrent cervical cancer.

Long non-coding RNA DLEU2 drives EMT and glycolysis in endometrial cancer through HK2 by competitively binding with miR-455 and by modulating the EZH2/miR-181a pathway.

BACKGROUND: Epithelial-to-mesenchymal transition (EMT) and aerobic glycolysis are fundamental processes implicated in cancer metastasis. Although increasing evidence demonstrates an association between EMT induction and enhanced aerobic glycolysis in human cancer, the mechanisms linking these two conditions in endometrial cancer (EC) cells remain poorly defined. METHODS: We characterized the role and molecular mechanism of the glycolytic enzyme hexokinase 2 (HK2) in mediating EMT and glycolysis and investigated how long noncoding RNA DLEU2 contributes to the stimulation of EMT and glycolysis via upregulation of HK2 expression. RESULTS: HK2 was highly expressed in EC tissues, and its expression was associated with poor overall survival. Overexpression of HK2 effectively promoted EMT phenotypes and enhanced aerobic glycolysis in EC cells via activating FAK and its downstream ERK1/2 signaling. Moreover, microRNA-455 (miR-455) served as a tumor suppressor by directly interacting with HK2 mRNA and inhibiting its expression. Furthermore, DLEU2 displayed a significantly higher expression in EC tissues, and increased DLEU2 expression was correlated with worse overall survival. DLEU2 acted as an upstream activator for HK2-induced EMT and glycolysis in EC cells through two distinct mechanisms: (i) DLEU2 induced HK2 expression by competitively binding with miR-455, and (ii) DLEU2 also interacted with EZH2 to silence a direct inhibitor of HK2, miR-181a. CONCLUSIONS: This study identified DLEU2 as an upstream activator of HK2-driven EMT and glycolysis in EC cells and provided significant mechanistic insights for the potential treatment of EC.

The difficulty to diagnose cervical cancer developing in the perinatal period with the first-trimester cytology: A retrospective study.

AIM: Cytological cervical cancer screening for pregnant women is routinely performed and still plays an essential role in Japan because of the considerably low rate of human pappillomavirus (HPV) vaccination. Though almost all pregnant women undergo cytological screening at their first trimester, we experienced invasive cervical cancers (ICC) diagnosed during pregnancy or postpartum period. We investigated the characteristics of perinatally diagnosed ICCs to clarify the difficulty in diagnosis during the pregnancy. METHODS: We retrospectively reviewed the clinical data on ICC diagnosed during pregnancy or within 1 year after delivery from 2010 to 2018 at Hokkaido University Hospital. RESULTS: We identified 18 ICC patients, and the median follow-up period was 46.5 months. Among eight patients with negative for intraepithelial lesion or malignancy (NILM), the mean duration to reach ICC diagnosis was 10.7 months, seven had stage IB1 or worse, and one was dead. On the other hand, among 10 women with abnormal cytology, the mean duration for diagnosis was 1.4 months, and 6 had stage IB1 or worse, and 1was dead. In terms of the timing of the final diagnosis, 8 were during pregnancy and 10 in the postpartum periods. Among eight pregnant patients, three resulted in a preterm delivery (33, 34, and 35 gestational weeks), and four terminated their pregnancies. One decided to continue the pregnancy until the term period. We performed conization in one patient and hysterectomy in seven. CONCLUSION: A part of cytological examinations of pregnant women may result in presumed false-negative or underestimation, which keeps them away from the additional examination to find ICC.

Initiatives and achievements of the Japanese Society of Obstetrics and Gynecology, Obstetrics and Gynecology MIRAI Committee 2020.

BACKGROUNDS: In 2013, the total number of obstetrician-gynecologists decreased. The Japanese Society of Obstetrics and Gynecology established the Obstetrics and Gynecology MIRAI Committee in 2015. Within the MIRAI Committee, Japanese Trainees in Obstetrics and Gynecology (JTOG) was established; it was comprised of 20 promising young obstetrician-gynecologists recommended from regions across Japan. The office term is 2 years. OBJECTIVE: The purpose of this report is to learn and inform about the results of MIRAI's activities. METHODS: We surveyed the trends in new obstetrician-gynecologists and also matched each seminar participant with them. RESULT: The number of new memberships has been increasing since the nadir in 2016. In particular, there are over 100 more new physicians specializing in the field in 2020 than there were at the nadir in 2016. It was revealed that approximately 50% of the participants in the summer school specialized in obstetrics and gynecology. Furthermore, approximately 70% of POP2 participants specialized in obstetrics and gynecology, which shows that these two recruitment seminars are extraordinarily effective events that result in an increase in the number of new obstetricians and gynecologists. CONCLUSION: We conclude that the activities of this MIRAI Committee and JTOG have been effective. With the spread of COVID-19 and the inability of obstetrician-gynecologists and students/clinical trainees to perform social distancing, it is currently difficult to hold hands-on seminars. However, we hope that new JTOG members will be able to create a new seminar format.

Critical Roles of PIWIL1 in Human Tumors: Expression, Functions, Mechanisms, and Potential Clinical Implications.

P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs) are a class of small non-coding RNA molecules that are 24-31 nucleotides in length. PiRNAs are thought to bind to PIWI proteins (PIWL1-4, a subfamily of Argonaute proteins), forming piRNA/PIWI complexes that influence gene expression at the transcriptional or post-transcriptional levels. However, it has been recently reported that the interaction of PIWI proteins with piRNAs does not encompass the entire function of PIWI proteins in human tumor cells. PIWIL1 (also called HIWI) is specifically expressed in the testis but not in other normal tissues. In tumor tissues, PIWIL1 is frequently overexpressed in tumor tissues compared with normal tissues. Its high expression is closely correlated with adverse clinicopathological features and shorter patient survival. Upregulation of PIWIL1 drastically induces tumor cell proliferation, epithelial-mesenchymal transition (EMT), invasion, cancer stem-like properties, tumorigenesis, metastasis and chemoresistance, probably via piRNA-independent mechanisms. In this article, we summarize the current existing literature on PIWIL1 in human tumors, including its expression, biological functions and regulatory mechanisms, providing new insights into how the dysregulation of PIWIL1 contributes to tumor initiation, development and chemoresistance through diverse signaling pathways. We also discuss the most recent findings on the potential clinical applications of PIWIL1 in cancer diagnosis and treatment.

PD-L1 Is a Tumor Suppressor in Aggressive Endometrial Cancer Cells and Its Expression Is Regulated by miR-216a and lncRNA MEG3.

BACKGROUND: Poorly differentiated endometrioid adenocarcinoma and serous adenocarcinoma represent an aggressive subtype of endometrial cancer (EC). Programmed death-ligand-1 (PD-L1) was known to exhibit a tumor cell-intrinsic function in mediating immune-independent tumor progression. However, the functional relevance of tumor cell-intrinsic PD-L1 expression in aggressive EC cells and the mechanisms regulating its expression remain unknown. METHODS: PD-L1 expression in 65 EC tissues and 18 normal endometrium samples was analyzed using immunohistochemical staining. The effects of PD-L1 on aggressive EC cell growth, migration and invasion were investigated by cell functional assays. Luciferase reporter assays were used to reveal the microRNA-216a (miR-216a)-dependent mechanism modulating the expression of PD-L1. RESULTS: Positive PD-L1 expression was identified in 84% of benign cases but only in 12% of the EC samples, and the staining levels of PD-L1 in EC tissues were significantly lower than those in the normal tissues. Higher PD-L1 expression predicts favorable survival in EC. Ectopic expression of PD-L1 in aggressive EC cells results in decreased cell proliferation and the loss of mesenchymal phenotypes. Mechanistically, PD-L1 exerts the anti-tumor effects by downregulating MCL-1 expression. We found that PD-L1 levels in aggressive EC cells are regulated by miR-216a, which directly targets PD-L1. We further identified a mechanism whereby the long non-coding RNA MEG3 represses the expression of miR-216a, thereby leading to increased PD-L1 expression and significant inhibition of cell migration and invasion. CONCLUSION: These results reveal an unappreciated tumor cell-intrinsic role for PD-L1 as a tumor suppressor in aggressive EC cells, and identify MEG3 and miR-216a as upstream regulators of PD-L1.

Tailored radical hysterectomy for locally advanced cervical cancer.

OBJECTIVE: The survival and prognostic factors for locally advanced cervical cancer treated with nerve-sparing Okabayashi-Kobayashi radical hysterectomy have not been elucidated. We aimed to evaluate the oncological outcomes of those patients after radical hysterectomy with adjuvant chemotherapy. METHODS: This retrospective cohort study was conducted from January 2002 to December 2011. Treatment was conducted at a single tertiary center in northern Japan. We used the Okabayashi-Kobayashi radical hysterectomy with lymphadenectomy. We applied unilateral nerve preservation for stage IIA/IIB cancer if there was a one-sided extension of the disease outside the cervix. Indication for adjuvant therapy was based on Sedlis criteria. High-risk was defined as evidence of lymph node metastasis, pathological parametrial invasion, and a positive/close surgical margin. The choice of adjuvant therapy was chemotherapy which consisted of paclitaxel and cisplatin. RESULTS: The study included 76 early-stage IB1 (≤4 cm) and IIA1 cervical cancer and 45 locally advanced stage IB2 (>4 cm), IIA2, and IIB disease treated consecutively. The median follow-up was 106 (range: 6-203) months. There were 18 (15%) patients with recurrence, with five of 76 in the early-stage (7%) and 13 of 45 in the locally advanced disease (29%) (P<0.001). For locally advanced cervical cancer, pT classification (P<0.001), lymph node metastasis (P=0.007), and histology (P=0.05) were associated with locoregional recurrence. The five-year locoregional recurrence rate in the locally advanced disease was 20% and 5% in the early-stage disease (P=0.01). The five-year disease-free survival in the locally advanced cervical cancer was 71% and 93% in the early-stage disease (P<0.001). The overall survival in locally advanced disease depended on the adeno-type histology and lymph node metastasis. CONCLUSION: The tailored use of nerve-sparing Okabayashi-Kobayashi radical hysterectomy with adjuvant chemotherapy based on tumor histology and lymph node metastasis may be a possible option as a treatment of locally advanced cervical cancer in selected patients.

The Expression, Functions and Mechanisms of Circular RNAs in Gynecological Cancers.

Circular RNAs (circRNAs) are covalently closed, endogenous non-coding RNAs and certain circRNAs are linked to human tumors. Owing to their circular form, circRNAs are protected from degradation by exonucleases, and therefore, they are more stable than linear RNAs. Many circRNAs have been shown to sponge microRNAs, interact with RNA-binding proteins, regulate gene transcription, and be translated into proteins. Mounting evidence suggests that circRNAs are dysregulated in cancer tissues and can mediate various signaling pathways, thus affecting tumorigenesis, metastasis, and remodeling of the tumor microenvironment. First, we review the characteristics, biogenesis, and biological functions of circRNAs, and describe various mechanistic models of circRNAs. Then, we provide a systematic overview of the functional roles of circRNAs in gynecological cancers. Finally, we describe the potential future applications of circRNAs as biomarkers for prognostic stratification and as therapeutic targets in gynecological cancers. Although the function of most circRNAs remains elusive, some individual circRNAs have biologically relevant functions in cervical cancer, ovarian cancer, and endometrial cancer. Certain circRNAs have the potential to serve as biomarkers and therapeutic targets in gynecological cancers.

Four versus six chemotherapy cycles in endometrial carcinoma with a high risk of recurrence: a retrospective study.

OBJECTIVE: This study compared the survival outcomes and the incidence of chemotherapy-related adverse events in endometrial cancer patients who received four and six cycles of adjuvant chemotherapy to examine the optimal number of adjuvant chemotherapy cycles. METHODS: A total of 112 patients with endometrial cancer with a high risk of recurrence were retrospectively enrolled; 46 patients received four cycles and 66 received six cycles of adjuvant chemotherapy. Between-group differences of overall survival, disease-free survival, hematological and non-hematological toxicities were analyzed. Baseline patient's background differences were assessed with inverse probability of treatment weighting using propensity score. RESULTS: Overall and disease-free survivals between the two groups were not significantly different. Paclitaxel + carboplatin, every 3-4 weeks was the most frequently used chemotherapy regimen in both groups. Patients in the six-cycle chemotherapy group developed neutropenia G4 or febrile neutropenia more frequently than those in the four-cycle group; odds ratio (95% confidence interval) is 4.07 (1.51-10.96). Peripheral sensory neuropathy was the most frequently observed non-hematological toxicity; the incidence of peripheral sensory neuropathy was not significantly different between four- and six-cycle chemotherapy group, P = 0.832. The result was same in the subgroup analysis in patients who received TC regimen, P = 0.455. CONCLUSION: This study implies a possible benefit of fewer cycles of adjuvant chemotherapy in endometrial cancer patients with a high risk of recurrence because of the lower incidence of hematological toxicities without impairing survival outcomes.

MicroRNA-361-Mediated Inhibition of HSP90 Expression and EMT in Cervical Cancer Is Counteracted by Oncogenic lncRNA NEAT1.

Epithelial-mesenchymal transition (EMT) is a key process contributing to cervical cancer (CC) metastasis, and microRNAs (miRNAs) modulate the expression of genes implicated in EMT. However, the accurate role of miR-361 in CC-associated EMT and the mechanisms underlying its function in CC remains largely unknown. The functional roles of miR-361 in CC cells were explored by a series of cell functional assays. Luciferase reporter assays were used to demonstrate the potential interaction between miR-361, HSP90, and long non-coding RNA (lncRNA) NEAT1. We detected a reduction of miR-361 expression in CC tissues compared with normal tissues, and miR-361 overexpression inhibited invasion and EMT phenotypes of CC cells by directly targeting a key EMT activator HSP90. Additionally, we detected significantly higher levels of HSP90 in CC tissues compared with normal tissues, and high expression of HSP90 predicted a poorer prognosis. We further identified NEAT1 as a significantly upregulated lncRNA in CC tissues and high expression of NEAT1 was associated with worse survival in CC patients. NEAT1 directly repressed miR-361 expression and played an oncogenic role in CC cell invasion and sphere formation. Conclusions: These results demonstrated that miR-361 directly targets HSP90 to inhibit the invasion and EMT features, and NEAT1 functions as an oncogenic lncRNA that suppresses miR-361 expression and induces EMT and sphere formation in CC cells, thus providing critical insights into the molecular pathways operating in this malignancy.

L1CAM Predicts Adverse Outcomes in Patients with Endometrial Cancer Undergoing Full Lymphadenectomy and Adjuvant Chemotherapy.

BACKGROUND: L1 cell adhesion molecule (L1CAM) has been established as an important predictor of poor survival of early-stage endometrial cancer patients. We investigated whether L1CAM remains a significant predictor of poor survival of patients with advanced-stage endometrial cancer undergoing extensive surgical staging and adjuvant chemotherapy. METHODS: We prepared tissue microarray (TMA) from surgical tissue specimens of 161 endometrial cancer patients who underwent full lymphadenectomy combined with adjuvant chemotherapy for patients at risk for recurrence, and evaluated expression of L1CAM using immunohistochemistry. The correlation between L1CAM positivity and clinicopathological factors and the prognostic significance of L1CAM expression was investigated. RESULTS: Among 161 cases who had a follow-up duration of over 3 years, 48 cases (29.8%) showed positive staining for L1CAM. L1CAM positivity was significantly correlated with non-endometrioid histology (p < 0.0001), vascular invasion (p = 0.0157), and positive cytology (p = 0.005), and was a significant predictor of poor survival among advanced-stage patients, but not early-stage patients in our cohort. L1CAM-positive patients showed a higher recurrence rate and frequency of distant failure than L1CAM-negative patients. Multivariate analysis revealed that para-aortic lymph node metastasis (PANM) and L1CAM positivity were independent predictors of poor survival. Overall survival can be stratified into three groups by the combination of PANM and L1CAM positivity. CONCLUSION: L1CAM is an independent predictor of poor survival in endometrial cancer patients undergoing full lymphadenectomy and adjuvant chemotherapy, thus indicating that L1CAM can be clinically used as a biomarker to identify those patients at increased risk of recurrence.

MicroRNA-361: A Multifaceted Player Regulating Tumor Aggressiveness and Tumor Microenvironment Formation.

MicroRNA-361-5p (miR-361) expression frequently decreases or is lost in different types of cancers, and contributes to tumor suppression by repressing the expression of its target genes implicated in tumor growth, epithelial-to-mesenchymal transition (EMT), metastasis, drug resistance, glycolysis, angiogenesis, and inflammation. Here, we review the expression pattern of miR-361 in human tumors, describe the mechanisms responsible for its dysregulation, and discuss how miR-361 modulates the aggressive properties of tumor cells and alter the tumor microenvironment by acting as a novel tumor suppressor. Furthermore, we describe its potentials as a promising diagnostic or prognostic biomarker for cancers and a promising target for therapeutic development.

Long noncoding RNA NEAT1 drives aggressive endometrial cancer progression via miR-361-regulated networks involving STAT3 and tumor microenvironment-related genes.

BACKGROUND: High-grade endometrioid and serous endometrial cancers (ECs) are an aggressive subtype of ECs without effective therapies. The reciprocal communication between tumor cells and their surrounding microenvironment drives tumor progression. Long noncoding RNAs (lncRNAs) are key mediators of tumorigenesis and metastasis. However, little is known about the role of lncRNAs in aggressive EC progression and tumor microenvironment remodeling. METHODS: We performed an array-based lncRNA analysis of a parental HEC-50 EC cell population and derivatives with highly invasive, sphere-forming, and paclitaxel (TX)-resistant characteristics. We characterized the roles of the lncRNA NEAT1 in mediating aggressive EC progression in vitro and in vivo and explored the molecular events downstream of NEAT1. RESULTS: We identified 10 lncRNAs with upregulated expression (NEAT1, H19, PVT1, UCA1, MIR7-3HG, SNHG16, HULC, RMST, BCAR4 and LINC00152) and 10 lncRNAs with downregulated expression (MEG3, GAS5, DIO3OS, MIR155HG, LINC00261, FENDRR, MIAT, TMEM161B-AS1, HAND2-AS1 and NBR2) in the highly invasive, sphere-forming and TX-resistant derivatives. NEAT1 expression was markedly upregulated in early-stage EC tissue samples, and high NEAT1 expression predicted a poor prognosis. Inhibiting NEAT1 expression with small hairpin RNAs (shRNAs) diminished cellular proliferation, invasion, sphere formation, and xenograft tumor growth and improved TX response in aggressive EC cells. We showed that NEAT1 functions as an oncogenic sponge for the tumor suppressor microRNA-361 (miR-361), which suppresses proliferation, invasion, sphere formation and TX resistance by directly targeting the oncogene STAT3. Furthermore, miR-361 also suppressed the expression of multiple prometastatic genes and tumor microenvironment-related genes, including MEF2D, ROCK1, WNT7A, VEGF-A, PDE4B, and KPNA4. CONCLUSIONS: NEAT1 initiates a miR-361-mediated network to drive aggressive EC progression. These data support a rationale for inhibiting NEAT1 signaling as a potential therapeutic strategy for overcoming aggressive EC progression and chemoresistance.

Molecular-targeted therapies and precision medicine for endometrial cancer.

The overall survival rate of patients with early-stage endometrial cancer is relatively high; however, there are few treatment options for patients with advanced or recurrent endometrial cancer, and the prognosis of such patients remains poor. Recent progress in molecular-targeted therapies demonstrated that they have the potential to improve the long-term survival of cancer patients with appropriate biomarkers. However, the median progression-free survival of patients who received single-agent molecular-targeted therapy was <5 months, and the development of molecular-targeted therapies for endometrial cancer patients is urgently needed. This review highlights the previous efforts, including antiangiogenesis therapy, PI3K/AKT/mTOR pathway inhibitor treatment and epidermal growth factor receptor inhibitor treatment and reports on ongoing phase 2 clinical trials, including immune checkpoint inhibitor and PARP inhibitor. We also summarized the genetic background of endometrial cancer according to The Cancer Genome Atlas data and considered the theoretical background for future efforts to prolong the survival of patients with refractory endometrial cancer and for other interesting challenges.

EZH2 inhibition suppresses endometrial cancer progression via miR-361/Twist axis.

EZH2 inhibition and reactivation of tumor suppressor microRNAs (miRNAs) represent attractive anti-cancer therapeutic strategies. We found that EZH2-suppressed let 7b and miR-361, two likely tumor suppressors, inhibited endometrial cancer (EC) cell proliferation and invasion, and abrogated cancer stem cell-like properties. In EC cells, EZH2 induced and functioned together with YY1 to epigenetically suppress miR-361, which upregulated Twist, a direct target of miR-361. Treating EC cells with GSK343, a specific EZH2 inhibitor, mimicked the effects of siRNA-mediated EZH2 knockdown, upregulating miR-361 and downregulating Twist expression. Combining GSK343 with 5 AZA-2'-deoxycytidine synergistically suppressed cell proliferation and invasion in vitro, and decreased tumor size and weight in EC cell xenografted mice. Quantitative real-time PCR analysis of 24 primary EC tissues showed that lower let-7b and miR-361 levels were associated with worse patient outcomes. These results were validated in a larger EC patient dataset from The Cancer Genome Atlas. Our findings suggest that EZH2 drives EC progression by regulating miR-361/Twist signaling, and support EZH2 inhibition as a promising anti-EC therapeutic strategy.

Suppression of iASPP-dependent aggressiveness in cervical cancer through reversal of methylation silencing of microRNA-124.

Derepression of wild-type p53 by suppressing its negative inhibitor iASPP (Inhibitor of apoptosis-stimulating protein of p53) represents a potential therapeutic option for cervical cancer (CC). Here, we reported a novel functional significance of iASPP upregulation in cervical tumorigenesis: iASPP acts as a key promoter of CC cell proliferation, epithelial-mesenchymal transition, invasion and cancer stemness, by interacting with p53 to suppress p53-mediated transcription of target genes and reducing p53-responsive microRNA-34a levels. Moreover, we demonstrate that miR-124, directly targeting iASPP, reduces expression of iASPP and attenuates CC cell growth and invasiveness. Low miR-124 expression is inversely correlated with increased expression of iASPP mRNA in CC tissues. In a cohort of 40 patients with CC, the low miR-124 expression was correlated with poor 5-year overall survival (P = 0.0002) and shorter disease-free survival 5-year (P = 0006). Treatment with the DNA methyltransferase inhibitor Zebularine increases miR-124 expression and retards CC cell growth and invasion with minimal toxicity to normal cells. Even at a non-toxic concentration, Zebularine was effective in suppressing CC cell invasion and migration. Altogether, the restoration of miR-124 reduces iASPP expression and leads to p53-dependent tumor suppression, suggesting a therapeutic strategy to treat iASPP-associated CC.