Corrigendum: PHGDH Is Upregulated at Translational Level and Implicated in Platin-Resistant in Ovarian Cancer Cells.

[This corrects the article DOI: 10.3389/fonc.2021.643129.].

METTL14-mediated N6-methyladenosine modification of ITGB4 mRNA inhibits metastasis of clear cell renal cell carcinoma.

BACKGROUND: Integrin ß4 (ITGB4) participates in tumorigenesis and progression of several malignancies, but its role and related mechanisms in clear cell renal cell carcinoma (ccRCC) remain unclear. METHODS: Quantitative real-time PCR (qRT-PCR), western blot and immunohistochemistry were used to detect mRNA and protein levels of relevant genes. Biological functions of ITGB4 and methyltransferase-like 14 (METTL14) were determined by in vitro and in vivo experiments. The levels of N6-methyladenosine (m6A) in ccRCC tissues and adjacent normal tissues were calculated via total RNA m6A quantification assay. The m6A modification of ITGB4 was demonstrated via m6A RNA immunoprecipitation (MeRIP), RIP and luciferase reporter assays. RESULTS: ITGB4 was significantly overexpressed in ccRCC tissues and high level of ITGB4 predicted poor prognosis as well as metastasis. Functionally, ITGB4 stimulated ccRCC cell migration and invasion in vitro and metastasis in vivo with epithelial-mesenchymal transition (EMT) strengthened. Mechanically, the total levels of m6A were reduced in ccRCC tissues. METTL14, a favorable factor for ccRCC patients' prognosis, facilitated m6A modification on ITGB4 3'UTR and subsequently accelerated ITGB4 mRNA degradation, leading to its declined expression. Furthermore, the METTL14-mediated inhibition of ITGB4 expression was dependent on the YTH domain family protein 2 (YTHDF2), which acted as an m6A reader to bind to ITGB4 mRNA and to promote its decay. In addition, we demonstrated that knockdown of METTL14 promoted ccRCC cell migration, invasiveness and metastasis as well as stimulating the EMT process and the PI3K/AKT signal by overexpressing ITGB4. CONCLUSION: Our study reveals that METTL14 inhibits ITGB4 expression via m6A modification to attenuate metastasis and EMT of ccRCC cells, suggesting the METTL14/ITGB4 axis as a potential prognostic biomarker and therapeutic target for ccRCC. Video Abstract.

Deubiquitinase PSMD14 promotes ovarian cancer progression by decreasing enzymatic activity of PKM2.

Dysregulation of deubiquitination has been reported to contribute to carcinogenesis. However, the function and mechanism of deubiquitinating enzyme 26S proteasome non-ATPase regulatory subunit 14 (PSMD14) in the progression of ovarian cancer (OV), the deadliest gynecological cancer, still remains to be characterized. The present study demonstrated that PSMD14 was overexpressed in OV tissues and its higher levels correlated with a higher International Federation of Gynecology and Obstetrics (FIGO) stage in OV patients. A high level of PSMD14 expression was related to poor survival in OV patients. Knockdown and overexpression experiments elucidated that PSMD14 stimulated OV cell proliferation, invasion, and migration in vitro. Repression of PSMD14 suppressed OV tumor growth in vivo. PSMD14 inhibitor O-phenanthroline (OPA) effectively attenuated malignant behaviors of OV cells in vitro and OV tumor growth in vivo. Mechanistically, we uncovered that PSMD14 was involved in post-translational regulation of pyruvate kinase M2 isoform (PKM2). PSMD14 decreased K63-linked ubiquitination on PKM2, downregulated the ratio of PKM2 tetramers to dimers and monomers, and subsequently diminished pyruvate kinase activity and induced nuclear translocation of PKM2, contributing to aerobic glycolysis in OV cells. Collectively, our findings highlight the potential roles of PSMD14 as a biomarker and therapeutic candidate for OV.

PHGDH Is Upregulated at Translational Level and Implicated in Platin-Resistant in Ovarian Cancer Cells.

BACKGROUND: Platinum-based chemotherapy is the first line option for ovarian cancer. The development of resistance to such chemotherapy results in treatment failure, while the underlying mechanisms are poorly understood. METHODS: Clinical samples were collected from Shengjing Hospital of China Medical University. MTT assay was used to see the proliferation and chemoresistance of ovarian cancer cells. Transwell migration and Matrigel invasion assays was used to see the invasion ability of ovarian cancer cells. In addition, polysome profiling and tissue microarray and immunohistochemical staining were also used. The statistical significance of the difference was analyzed by ANOVA and post hoc Dunnett's test. RESULTS: PHGDH is the first enzyme responsible for serine biosynthesis pathway. The current study demonstrated that PHGDH is upregulated in platin-resistant ovarian cancer cells and tissues at the protein level. Importantly, knockdown of PHGDH suppressed, while overexpression of PHGDH increased the survival upon cisplatin exposure, invasiveness and spheroid formation of ovarian cancer cells. The current study demonstrated that PHGDH translation was upregulated in platin-resistant ovarian cancer. In addition, our study provided evidence that LncRNA RMRP (RNA Component of Mitochondrial RNA Processing Endoribonuclease) was upregulated in platin-resistant ovarian cancer, which promoted enrichment of RNA binding protein DDX3X (DEAD-Box Helicase 3 X-Linked) on the PHGDH mRNA to promote its translation. CONCLUSION: Collectively, the current study described that PHGDH was upregulated and conferred resistance of ovarian cancer cells to cisplatin, suggesting that cisplatin resistance could be overcome by targeting PHGDH. Our study also provided evidence that differential PHGDH protein expression was defined by its translation, and RNA binding protein DDX3X and LncRNA RMRP are regulators of its translation.

METTL13 inhibits progression of clear cell renal cell carcinoma with repression on PI3K/AKT/mTOR/HIF-1α pathway and c-Myc expression.

BACKGROUND: Clear cell renal cell carcinoma (ccRCC) is the most common and aggressive type of renal malignancy. Methyltransferase like 13 (METTL13) functions as an oncogene in most of human cancers, but its function and mechanism in ccRCC remains unreported. METHODS: qRT-PCR, western blotting and immunohistochemistry were used to detect METTL13's expression in tissues. The effects of METTL13 on ccRCC cells' growth and metastasis were determined by both functional experiments and animal experiments. Weighted gene co-expression network analysis (WGCNA) was performed to annotate METTL13's functions and co-immunoprecipitation (co-IP) was used to determine the interaction between METTL13 and c-Myc. RESULTS: METTL13 was underexpressed in ccRCC tissues compared to normal kidney tissues and its low expression predicted poor prognosis for ccRCC patients. The in vitro studies showed that knockdown and overexpression of METTL13 respectively led to increase and decrease in ccRCC cells' proliferation, viability, migratory ability and invasiveness as well as epithelial-mesenchymal transition (EMT). The in vivo experiment demonstrated the inhibitory effect that METTL13 had on ccRCC cells' growth and metastasis. Bioinformatic analyses showed various biological functions and pathways METTL13 was involved in. In ccRCC cells, we observed that METTL13 could negatively regulate PI3K/AKT/mTOR/HIF-1α pathway and that it combined to c-Myc and inhibited c-Myc protein expression. CONCLUSIONS: In general, our finding suggests that high expression of METTL13 is associated with favorable prognosis of ccRCC patients. Meanwhile, METTL13 can inhibit growth and metastasis of ccRCC cells with participation in multiple potential molecular mechanisms. Therefore, we suggest METTL13 can be a new diagnostic and therapeutic target for ccRCC in the future.

TMEM119 facilitates ovarian cancer cell proliferation, invasion, and migration via the PDGFRB/PI3K/AKT signaling pathway.

BACKGROUND: Ovarian cancer (OV) is the deadliest gynecological cancer. Transmembrane protein 119 (TMEM119) has been reported as oncogene in several human cancers. However, the function of TMEM119 in OV is still poorly known. METHODS: Western blot and qRT-PCR were used to analyze TMEM119 levels. Transwell assays, wound healing assays, CCK-8 assays and EdU cell proliferation assays were designed to explore the function and potential mechanism of TMEM119 in malignant biological behaviors in OV. RESULTS: TMEM119 was observed to be overexpressed in OV tissues and associated with poor survival in OV patients. Knockdown and overexpression experiments demonstrated that TMEM119 promoted proliferation, invasion, and migration in OV cells in vitro. TMEM119 mRNA expression was related to the pathways of focal adhesion according to Gene Set Enrichment Analyses and was correlated with the mRNA expression level of platelet-derived growth factor receptor beta (PDGFRB). TMEM119 exerted oncogenic effects partially by regulating the expression of PDGFRB and by activating the PI3K/AKT signaling pathway. CONCLUSIONS: Collectively, our findings highlight the potential role of TMEM119 in the malignant biological behavior of OV, which may serve as a potential biomarker and a therapeutic candidate for OV.

An 18-gene signature based on glucose metabolism and DNA methylation improves prognostic prediction for urinary bladder cancer.

BACKGROUND: Glucose metabolism and DNA methylation play important roles in cancers. We aimed to identify glucose metabolism-related genes that were DNA methylation associated to establish a prognostic signature of bladder cancer (BLCA). METHODS: With BLCA sample transcriptome data from The Cancer Genome Atlas (TCGA) and methylation data from TCGA 450 K microarray, glucose metabolism-related genes associated to prognosis and DNA methylation were identified and a prognostic signature was established. GSEA and WGCNA analysis were performed and two genes, UCHL1 and PYCR1, were selected for functional validations. RESULTS: 18 target genes were identified and the signature based on them was considered an effective and independent prognostic factor. Several pathways were enriched in the high-risk group by GSEA and three modules of genes were identified by WGCNA. UCHL1 and PYCR1 proliferated proliferation, migration and invasion ability of bladder cancer cells. CONCLUSIONS: The 18-gene signature is an independent prognostic factor for bladder cancer patients.

The role of ubiquitination and deubiquitination in cancer metabolism.

Metabolic reprogramming, including enhanced biosynthesis of macromolecules, altered energy metabolism, and maintenance of redox homeostasis, is considered a hallmark of cancer, sustaining cancer cell growth. Multiple signaling pathways, transcription factors and metabolic enzymes participate in the modulation of cancer metabolism and thus, metabolic reprogramming is a highly complex process. Recent studies have observed that ubiquitination and deubiquitination are involved in the regulation of metabolic reprogramming in cancer cells. As one of the most important type of post-translational modifications, ubiquitination is a multistep enzymatic process, involved in diverse cellular biological activities. Dysregulation of ubiquitination and deubiquitination contributes to various disease, including cancer. Here, we discuss the role of ubiquitination and deubiquitination in the regulation of cancer metabolism, which is aimed at highlighting the importance of this post-translational modification in metabolic reprogramming and supporting the development of new therapeutic approaches for cancer treatment.

SLC7A2 serves as a potential biomarker and therapeutic target for ovarian cancer.

The solute carrier (SLC) family is the largest group of membrane transporters, but their functions in ovarian cancer (OV) remain unclear. We analyzed SLC family members with amino acids-transporting functions in OV. The mRNA expression levels and prognostic values of SLCs in OV were analyzed in the Gene Expression Profiling Interactive Analysis and Kaplan-Meier Plotter database. Solute carrier family 7 member 2 (SLC7A2), which showed differential expression and the most significant prognostic value, was selected for further analyses. The cBioPortal database, Gene Set Enrichment Analysis and Weighted Correlation Network Analysis were used to explore the potential functions and molecular mechanisms of SLC7A2 in OV. Validations in our own samples and in Gene Expression Omnibus datasets were conducted. Functional validation in OV cell lines was carried out. In total, 73 SLC family members were analyzed. Seven members were upregulated while 11 members were downregulated in OV and 15 members were protective factors for prognosis while 12 members were risk factors. SLC7A2 was downregulated in OV, and it was positively associated with prognosis. Knockdown of SLC7A2 promoted viability, invasion and migration of OV cells. These SLC family members and in particular SLC7A2 represented novel biomarkers for diagnosis and treatment for OV.

An effective method using laparoscopy in treatment of upper vaginal leiomyoma.

OBJECTIVE: To introduce an effective approach using laparoscopy in the treatment of upper vaginal leiomyoma. DESIGN: Step-by-step video explanation of the surgical procedure with still pictures and surgical video clips to demonstrate the detailed technique, approved by the Shengjing Hospital of China Medical University. SETTING: Hospital. PATIENT(S): A 34-year-old woman diagnosed with 5-cm upper vaginal leiomyoma, who had sexual discomfort for 5 years. INTERVENTION(S): Using laparoscopy in the treatment of upper vaginal leiomyoma consists of five steps: first lysing the pelvic adhesion; exploring the pelvic cavity and locating the vaginal leiomyoma through gynecologic examination by the assistant; recognizing the position between leiomyoma and ureter and carefully dissociating ureter while avoiding injury; completely enucleating and resecting the vaginal leiomyoma using laparoscopy; and exploring the ureter, rectum, and uterine artery to make sure there was no injury. MAIN OUTCOME MEASURE(S): Value and feasibility of using laparoscopy in treatment of upper vaginal leiomyoma. RESULT(S): The vaginal leiomyoma was removed successfully using laparoscopic operation and the operative time was 95 minutes. In the follow-up period, the patient did not report any symptoms, and she became pregnant at the time of the 20th month after operation and underwent a vaginal delivery at full-term. CONCLUSION(S): For upper vaginal leiomyoma treatment, laparoscopic operation could present a clear visual field to avoid injury of bladder, ureter, rectum, and uterine artery. Laparoscopic operation is safe and feasible in treatment of upper vaginal leiomyoma.

Chemoresistance-associated alternative splicing signatures in serous ovarian cancer.

Primary platinum-based chemoresistance occurs in ~30% of patients with serous ovarian cancer. Chemoresistance is the main cause of disease recurrence, and accurate predictors to identify these patients with chemoresistance are required. Alternative splicing (AS) is a post-transcriptional modification process that is altered in cancer. A possible association between AS and chemoresistance is unclear and needs to be studied comprehensively in ovarian cancer. In the present study, RNA-sequencing data and clinical information for 320 patients with ovarian serous cystadenocarcinoma (OV) were downloaded from The Cancer Genome Atlas (TCGA) database. Splicing events were determined using the TCGA SpliceSeq tool. Seven types of AS events were identified. Univariate and multivariate logistic analyses were performed, and predictive models for OV chemoresistance were established, as well as a splicing network. A total of 22,036 AS events were identified in 7,404 genes, with 915 AS events detected in 677 genes that were significantly associated with chemoresistance in patients with OV. A receiver operating characteristic (ROC) curve was constructed for resistance predictive models composed of the most significant AS events. The area under the ROC curve was 0.931, indicating strong and efficient prediction of chemoresistance. Additionally, the high-risk score was associated with shorter overall survival. The splicing correlation network suggested a potential role of splicing factors in chemoresistance. In summary, the present study created a powerful predictor for primary platinum-based chemoresistance in patients with OV, identified splicing networks that could be involved in potential mechanisms of chemoresistance and provided potential targets to overcome chemoresistance.

Laparoscopic myomectomy using self-made retrieval bag to contain tissue extraction.

OBJECTIVE: To introduce an effective approach using a self-made retrieval bag during laparoscopic myomectomy to contain tissue extraction. DESIGN: Step-by-step video explanation of the surgical procedure with still pictures and surgical video clips to demonstrate the detailed technique, approved by the Shengjing Hospital of China Medical University. SETTING: University hospital. PATIENT(S): A 32-year-old woman diagnosed with a uterine myoma (diameter, 6 cm). She had endured 5 years of intermittent lower abdominal pain and 2 years of infertility. INTERVENTION(S): A self-made retrieval bag during laparoscopic myomectomy was used (consists of four steps) to contain tissue extraction. 1. Self-made retrieval bag using a sterile medical bag. 2. Inspect the pelvic cavity, evaluate and determine the location and number of myomas. 3. Resect the myoma. 4. Morcellate the myoma into pieces inside the retrieval bag using laparoscopic power morcellation. MAIN OUTCOME MEASURE(S): Value and feasibility of using a self-made retrieval bag in laparoscopic myomectomy. RESULT(S): The myoma was successfully and completely resected by laparoscopy using a self-made retrieval bag to contain tissue extraction. Operative time was 93 minutes. In the follow-up period, the patient did not report any symptom of iatrogenic parasitic myoma. The woman had a pregnancy at month 26 after operation and underwent a cesarean section. This resulted in a full-term baby. CONCLUSION(S): Our surgical approach demonstrated a number of noteworthy advantages. The use of retrieval bag to contain tissue extraction during laparoscopic morcellation can avoid the risk of iatrogenic parasitic myoma. The retrieval bag is self-made using a sterile packing bag, which is cost free and also reduces operative expenses.

An Effective Method Combining Various Endoscopes in the Treatment of Intravesical Migrated Intrauterine Device.

OBJECTIVE: To introduce an effective method combining various endoscopes in the treatment of intravesical migrated intrauterine device (IUD). DESIGN: A step-by-step explanation of the surgery using video, approved by the Shengjing Hospital of China Medical University. SETTING: Shengjing Hospital of China Medical University. INTERVENTIONS: A 39-year-old young woman, in whom an IUD was inserted 2 months prior, presented with frequent urination after IUD insertion. Cystoscope and pelvic computed tomography were performed, and the results showed an IUD in the bladder. The migrated IUD was found partly in the uterus and partly in the bladder by hysteroscope and cystoscope. Management of the migrated IUD consists of 4 steps: (1) lysing the adhesion between the bladder and uterus, (2) suturing the bladder and taking the IUD part out of the bladder, (3) removing the IUD part in the uterus, and (4) suturing the bladder again to reinforce it and suturing the uterus. CONCLUSION: The migrated IUD in the bladder was successfully and completely extracted by the method combining various endoscopes; operative time was 56 minutes. In the follow-up period the patient did not report any symptoms of frequency urination. This surgical process has the following characteristics: Preoperative examination should be performed to clarify the ectopic site of the IUD, various endoscopes should be combined for diagnosis and treatment, and endoscopic surgery is an effective treatment method for migrated IUD.

An effective "water injection"-assisted method for excision of ovarian endometrioma by laparoscopy.

OBJECTIVE: To introduce an effective approach for excision of ovarian endometrioma by "water injection"-assisted laparoscopy treatment. DESIGN: Step-by-step video explanation of the surgical procedure with still pictures and surgical video clips to demonstrate the detailed technique, approved by the Shengjing Hospital of China Medical University. SETTING: Hospital. PATIENTS: A 26-year-old young woman diagnosed with a 6 cm in diameter right ovarian cyst, who endured 5 years of dysmenorrhea. INTERVENTIONS: The "water injection"-assisted laparoscopic excision of ovarian endometrioma consists of five steps: rupture the ovarian endometrial cyst and remove the "chocolate fluid;" inject the "water" (diluted vasopressin solution) into the interface between endometrioma and ovarian parenchyma; stop injecting until the solution overflow; separate the endometrioma away from the ovarian parenchyma; and suture the ovary. MAIN OUTCOME MEASURES: Value and feasibility of "water injection"-assisted laparoscopic excision of ovarian endometrioma. RESULTS: The "water injection"-assisted laparoscopic excision of ovarian endometrioma was feasible and effective. In the follow-up period, the patient did not report any symptom of dysmenorrhea; and the sex hormone and antimüllerian hormone tests reached to normal levels. CONCLUSION: Our surgical approach demonstrated several noteworthy advantages. After "water injection", the endometrioma and ovarian parenchyma was easily distinguished and separated. The approach avoided normal ovarian tissue destruction during endometrioma separation. The utilization of diluted vasopressin solution might decrease bleeding of ovarian wound. Considering its simplicity of realization, our surgical approach should be promoted to more reproductive-age patients.