RNA m5C modification upregulates E2F1 expression in a manner dependent on YBX1 phase separation and promotes tumor progression in ovarian cancer.

5-Methylcytosine (m5C) is a common RNA modification that modulates gene expression at the posttranscriptional level, but the crosstalk between m5C RNA modification and biomolecule condensation, as well as transcription factor-mediated transcriptional regulation, in ovarian cancer, is poorly understood. In this study, we revealed that the RNA methyltransferase NSUN2 facilitates mRNA m5C modification and forms a positive feedback regulatory loop with the transcription factor E2F1 in ovarian cancer. Specifically, NSUN2 promotes m5C modification of E2F1 mRNA and increases its stability, and E2F1 binds to the NSUN2 promoter, subsequently reciprocally activating NSUN2 transcription. The RNA binding protein YBX1 functions as the m5C reader and is involved in NSUN2-mediated E2F1 regulation. m5C modification promotes YBX1 phase separation, which upregulates E2F1 expression. In ovarian cancer, NSUN2 and YBX1 are amplified and upregulated, and higher expression of NSUN2 and YBX1 predicts a worse prognosis for ovarian cancer patients. Moreover, E2F1 transcriptionally regulates the expression of the oncogenes MYBL2 and RAD54L, driving ovarian cancer progression. Thus, our study delineates a NSUN2-E2F1-NSUN2 loop regulated by m5C modification in a manner dependent on YBX1 phase separation, and this previously unidentified pathway could be a promising target for ovarian cancer treatment.

Upregulation of LRRC8A by m5C modification-mediated mRNA stability suppresses apoptosis and facilitates tumorigenesis in cervical cancer.

Cervical cancer (CC) is one of the most common gynecological malignancies with poor prognosis for advanced CC patients. LRRC8A is a volume-regulated anion channel protein involved in cellular homeostasis, but its role in CC remains largely unknown. In this study, we found that LRRC8A is elevated in CC and associated with poor prognosis. LRRC8A maintains cell survivals under the hypotonic condition, and promotes tumorigenesis through apoptosis suppression in vitro and in vivo. Notably, LRRC8A is upregulated by NSUN2-mediated m5C modification. m5C modified-LRRC8A mRNA is bound by the RNA binding protein YBX1 followed by the increased RNA stability. Moreover, loss of NSUN2 suppresses the proliferation and metastasis of CC cells, and NSUN2 expression is positively correlated with LRRC8A expression in CC. Altogether, our study demonstrates that the NSUN2-m5C-LRRC8A axis is crucial and would be a potential therapeutic target for CC.

The RNA binding protein QKI5 suppresses ovarian cancer via downregulating transcriptional coactivator TAZ.

RNA-binding proteins (RBPs) are a set of proteins involved in many steps of post-transcriptional regulation to maintain cellular homeostasis. Ovarian cancer (OC) is the most deadly gynecological cancer, but the roles of RBPs in OC are not fully understood. Here, we reported that the RBP QKI5 was significantly negatively correlated with aggressive tumor stage and worse prognosis in serous OC patients. QKI5 could suppress the growth and metastasis of OC cells both in vitro and in vivo. Transcriptome analysis showed that QKI5 negatively regulated the expression of the transcriptional coactivator TAZ and its downstream targets (e.g., CTGF and CYR61). Mechanistically, QKI5 bound to TAZ mRNA and recruited EDC4, thus decreasing the stability of TAZ mRNA. Functionally, TAZ was involved in the QKI5-mediated tumor suppression of OC cells, and QKI5 expression was inversely correlated with TAZ, CTGF, and CYR61 expression in OC patients. Together, our study indicates that QKI5 plays a tumor-suppressive role and negatively regulates TAZ expression in OC.

PHLDA1 Modulates the Endoplasmic Reticulum Stress Response and is required for Resistance to Oxidative Stress-induced Cell Death in Human Ovarian Cancer Cells.

Objective: Pleckstrin homology-like domain family A member 1 (PHLDA1) has been implicated in the regulation of apoptosis in a variety of normal cell types and cancers. However, its precise pathophysiological functions remain unclear. Here, we examined the expression of PHLDA1 in human ovarian cancer (OvCa), the most lethal gynecologic malignancy, and investigated its functions in vitro. Materials and Methods: The expression of PHLDA1 was detected by reverse-transcription quantitative PCR (RT-qPCR), immunohistochemical analysis, or western blotting, silencing of PHLDA was achieved by shRNA, cell proliferation was detected by MTT assay, apoptosis was detected by flow cytometric analysis, PHLDA1 transcriptional activity was detected by dual luciferase reporter assay. Results: PHLDA1 mRNA levels were significantly higher in serous OvCa specimens compared with normal ovarian tissue, confirmed by immunohistochemical staining of PHLDA1 protein, which also indicated the expression was predominantly cytoplasmic. Bioinformatics analysis of publicly available datasets indicated that PHLDA1 expression in clinical specimens was significantly associated with disease stage, progression-free survival, and overall survival. In human OvCa cell lines, shRNA-mediated silencing of PHLDA1 expression enhanced apoptosis after exposure to oxidative stress- and endoplasmic reticulum stress-inducing agents. PHLDA1 silencing increased not the expression of anti-apoptotic or autophagy-related proteins, but the expression of ER stress response-associated proteins. Conclusion: PHLDA1 modulates the susceptibility of human OvCa cells to apoptosis via the endoplasmic reticulum stress response pathway.

YTHDF1 Aggravates the Progression of Cervical Cancer Through m6A-Mediated Up-Regulation of RANBP2.

N6-methyladenosine (m6A) is the most common post-transcriptional modification of RNA in eukaryotes, which has been demonstrated to play important roles in various cancers. YTHDF1 acts as a crucial m6A "reader" and regulates the fate of m6A modified mRNA. However, its role in cervical cancer remains unknown. In this study, we showed that YTHDF1 was highly expressed in cervical cancer, and was closely associated with the poor prognosis of cervical cancer patients. YTHDF1 knockdown suppressed the growth, migration and invasion, and induced apoptosis of cervical cancer cells. Moreover, YTHDF1 knockdown inhibited tumorigenesis of cervical cancer cells in vivo. Through combined on-line data analysis of RIP-seq, meRIP-seq and Ribo-seq upon YTHDF1 knockdown, RANBP2 was identified as the key target of YTHDF1 in cervical cancer cells. YTHDF1 regulated RANBP2 translation in an m6A-dependent manner without effect on its mRNA expression. RANBP2 potentiated the growth, migration and invasion of cervical cancer cells. Our study demonstrated the oncogenic role of YTHDF1 in cervical cancer by regulating RANBP2 expression and YTHDF1 represents a potential target for cervical cancer therapy.

[Knockdown of YTH N6-methyladenosine RNA binding protein 2 (YTHDF2) inhibits cell proliferation and promotes apoptosis in cervical cancer cells].

Objective To investigate the effect of YTH N6-methyladenosine RNA binding protein 2 (YTHDF2) knockdown on proliferation, cell cycle and apoptosis of cervical cancer cells. Methods Human Protein Atlas database was used to analyze the expression of YTHDF2 in cervical cancer and its relationship with the survival. Immunohistochemistry was performed to detect protein expression of YTHDF2 in 31 cervical cancer tissue samples and 31 normal cervical tissue samples. Then short hairpin RNAs (shRNAs) targeting YTHDF2 were designed and cloned into lentivirus expression vector. HeLa and SiHa cells were infected with the lentivirus. RNA and protein expression of YTHDF2 were measured by real-time quantitative PCR and Western blotting, respectively. Furthermore, CCK-8 assay and colony formation assay were conducted to detect the cell proliferation and flow cytometry was used to analyze the cell cycle and apoptosis. Results The database showed that cervical cancer patients with high YTHDF2 expression had poor prognosis. And YTHDF2 expression increased in the cervical cancer tissues compared with the normal tissues. Moreover, knockdown of YTHDF2 inhibited the cell proliferation, induced cell apoptosis, and arrested the cells at S phase in the HeLa and SiHa cells. Conclusion YTHDF2 expression is upregulated in cervical carcinoma. Knockdown of YTHDF2 can significantly inhibit cell proliferation and promote apoptosis in cervical carcinoma HeLa and SiHa cells.

Loss of hnRNPA2B1 inhibits malignant capability and promotes apoptosis via down-regulating Lin28B expression in ovarian cancer.

Ovarian cancer has the highest mortality rate among all gynecological cancers with its pathogenic mechanisms largely unknown. Here, we uncovered that ovarian cancer tissues exhibit higher heterogeneous nuclear ribonucleoprotein A2B1 (hnRNPA2B1) expression than normal ovarian epithelium tissues. Increased hnRNPA2B1 level matches along with poor prognosis of ovarian cancer patients. Importantly, hnRNPA2B1 inhibition hampers growth, reduces mobility of ovarian cancer cells in vitro and hinders xenograft tumor formation in vivo. Transcriptome profiling analysis reveals that hnRNPA2B1 dictates the expression of various important genes involved in tumorigenesis and Lin-28 Homolog B (Lin28B) is down-regulated upon hnRNPA2B1 loss. hnRNPA2B1 regulates expression of Lin28B via binding to Lin28B mRNA and enhancing its stability. Furthermore, knockdown of Lin28B reduces proliferation and mobility of ovarian cancer cells and impairs tumorigenesis in vivo, whereas Lin28B overexpression promotes xenograft tumor formation. Finally, re-expression of Lin28B in hnRNPA2B1 knockdown cells results in rescued phenotypes. Collectively, our results demonstrate that hnRNPA2B1 facilitates the malignant phenotype of ovarian cancer through activating Lin28B expression.

The m6A reader YTHDF1 promotes ovarian cancer progression via augmenting EIF3C translation.

N 6-Methyladenosine (m6A) is the most abundant RNA modification in mammal mRNAs and increasing evidence suggests the key roles of m6A in human tumorigenesis. However, whether m6A, especially its 'reader' YTHDF1, targets a gene involving in protein translation and thus affects overall protein production in cancer cells is largely unexplored. Here, using multi-omics analysis for ovarian cancer, we identified a novel mechanism involving EIF3C, a subunit of the protein translation initiation factor EIF3, as the direct target of the YTHDF1. YTHDF1 augments the translation of EIF3C in an m6A-dependent manner by binding to m6A-modified EIF3C mRNA and concomitantly promotes the overall translational output, thereby facilitating tumorigenesis and metastasis of ovarian cancer. YTHDF1 is frequently amplified in ovarian cancer and up-regulation of YTHDF1 is associated with the adverse prognosis of ovarian cancer patients. Furthermore, the protein but not the RNA abundance of EIF3C is increased in ovarian cancer and positively correlates with the protein expression of YTHDF1 in ovarian cancer patients, suggesting modification of EIF3C mRNA is more relevant to its role in cancer. Collectively, we identify the novel YTHDF1-EIF3C axis critical for ovarian cancer progression which can serve as a target to develop therapeutics for cancer treatment.

Characterization of the Expression of the RNA Binding Protein eIF4G1 and Its Clinicopathological Correlation with Serous Ovarian Cancer.

BACKGROUND: Ovarian cancer is the most lethal type of malignant tumor in gynecological cancers and is associated with a high percentage of late diagnosis and chemotherapy resistance. Thus, it is urgent to identify a tumor marker or a molecular target that allows early detection and effective treatment. RNA-binding proteins (RBPs) are crucial in various cellular processes at the post-transcriptional level. The eukaryotic translation initiation factor 4 gamma, 1(eIF4G1), an RNA-binding protein, facilitates the recruitment of mRNA to the ribosome, which is a rate-limiting step during the initiation phase of protein synthesis. However, little is known regarding the characteristics of eIF4G1 expression and its clinical significance in ovarian cancer. Therefore, we propose to investigate the expression and clinicopathological significance of eIF4G1 in ovarian cancer patients. METHODS: We performed Real-time PCR in 40 fresh serous ovarian cancer tissues and 27 normal ovarian surface epithelial cell specimens to assess eIF4G1mRNA expression. Immunohistochemistry (IHC) was used to examine the expression of eIF4G1 at the protein level in 134 patients with serous ovarian cancer and 18 normal ovarian tissues. Statistical analysis was conducted to determine the correlation of the eIF4G1 protein levels with the clinicopathological characteristics and prognosis in ovarian cancer. RESULTS: The expression of eIF4G1 was upregulated in serous ovarian cancer tissues at both the mRNA (P = 0.0375) and the protein (P = 0.0007) levels. The eIF4G1 expression was significantly correlated with the clinical tumor stage (P = 0.0004) and omentum metastasis (P = 0.024). Moreover, patients with low eIF4G1 protein expression had a longer overall survival time (P = 0.026). CONCLUSIONS: These data revealed that eIF4G1 is markedly expressed in serous ovarian cancer and that upregulation of the eIF4G1 protein expression is significantly associated with an advanced tumor stage. Besides, the patients with lower expression of eIF4G1 tend to have a longer overall survival time. Thus, eIF4G1 may contribute to the occurrence and metastasis of ovarian cancer and can serve as a potential therapeutic target for the treatment of ovarian cancer.

Advanced MRI manifestations of trigeminal ganglioneuroma: a case report and literature review.

BACKGROUND: Ganglioneuroma is a rare benign tumor originating from the sympathetic nerves, and its origination from the trigeminal nerves is even rarer. Only 4 cases of ganglioneuroma originating from the trigeminal nerve have previously been reported, and these studies only reported conventional MRI manifestations. To our knowledge, the advanced MRI features of trigeminal ganglioneuroma have not been reported thus far. CASE PRESENTATION: This study reports a case of trigeminal ganglioneuroma in the left cerebellopontine angle. Advanced MRI showed the following tumor characteristics: significantly increased perfusion on perfusion imaging; isointense on diffusion-weighted imaging, whorled appearance within the tumor and no significant signs of damage to the white matter fiber tracts in the fractional anisotropy color map, and compare to the adjacent brain tissue, Choline didn't show markedly elevation, and N-acetylaspartate peak showed slightly reduction on magnetic resonance spectroscopy. The tumor was completely resected, and the diagnosis of ganglioneuroma was confirmed by postoperative pathological examination. CONCLUSION: This case demonstrates the conventional as well as advanced MRI manifestations of this rare extra-axial tumor, which have never been previously reported. In addition, we reviewed the literature to demonstrate the advanced MRI features of trigeminal ganglioneuroma, in order to aid preoperative diagnosis and differentiation.

Primary diffuse large B cell lymphoma arising from a leiomyoma of the uterine corpus.

BACKGROUND: Primary diffuse large B cell lymphoma (DLBCL) of the uterus is rare, and primary DLBCL arising from a uterine leiomyoma (collision tumor) has not been reported in the literature. CASE PRESENTATION: We describe the clinical, histological, immunohistochemical, and molecular features of primary DLBCL arising from a leiomyoma in the uterine corpus. A 73-year-old female patient had a uterine mass for 23 years. An ultrasound scan revealed marked enlargement of the uterus, measuring 18.2 × 13 × 16.3 cm, with a 17.6 × 10.9 × 11.6 cm hypoechoic mass in the uterine corpus. The tumors consisted of medium- to large-sized cells exhibiting a diffuse pattern of growth with a well-circumscribed leiomyoma. The neoplastic cells strongly expressed CD79α, CD20 and PAX5. Molecular analyses indicated clonal B-cell receptor gene rearrangement. CONCLUSIONS: To the best of our knowledge, no previous cases of primary DLBCL arising from a leiomyoma have been reported. It is necessary to differentiate a diagnosis of primary DLBCL arising from a leiomyoma from that of leiomyoma with florid reactive lymphocytic infiltration (lymphoma-like lesion). Careful analysis of clinical, histological, immunophenotypic, and genetic features is required to establish the correct diagnosis.

Giant Myelolipoma in the Spleen: A Rare Case Report and Literature Review.

Myelolipomas are benign tumors, consisting of hematopoietic cells and mature adipose tissue, which mainly occur within the adrenal gland. Extra-adrenal myelolipomas are rare, and fewer than 60 cases have been reported in the literature. Here, we report a case of intrasplenic myelolipoma in a 42-year-old man with more than 1 month of abdominal pain. Computed tomography scanning revealed a giant, heterogeneous, well-demarcated mass in the spleen. Splenectomy was performed, and an intrasplenic giant mass was completely excised. The diagnosis of myelolipoma was made based on morphological examination. To the best of our knowledge, this is the third reported case of myelolipoma in the human spleen.

EGFR mutations in patients with lung adenocarcinoma in southwest China: are G719S/A and L861Q more likely detected in tumors derived from smokers?

BACKGROUND: The clinical characteristics of epidermal growth factor receptor (EGFR) hotspot mutations, such as deletions in exon 19, substitution of L858R in exon 21, and mutations in exon 20, have been widely reported in nonsmall cell lung cancer. However, the clinical features of other low frequency EGFR mutations in these four exons (especially the relationship with smoking history), eg, substitutions of G719S/A/C in exon 18 and L861Q in exon 21, remain unclear. This study investigated the relationship between G719S/A/C and L861Q mutations (in exon 18 and 21) and smoking history. METHODS: Specimens from 194 patients with lung adenocarcinoma were analyzed for EGFR mutations in exons 18-21 by high-resolution melting curve analysis and amplification refractory mutation technology to establish the relationship between G719S/A/C and L861Q mutations and smoking history. RESULTS: Ninety-six of 194 tumors (49.5%) were confirmed to be EGFR mutation-positive. Among these mutations, 71 of 104 (68.3%) were from never smokers, six of 17 (35.3%) were from former smokers, and 19 of 73 (26.0%) were from current smokers (P < 0.001). The mutation rate in heavy smokers (5/23, 21.7%) was significantly lower than in light smokers (20/67, 29.9%) and never smokers (71/104, 68.3%, P < 0.001). Seven low frequency EGFR mutations (four substitutions of G719S, and G719 A, respectively, and three of L861Q in exon 21) were identified. Five of these mutations were derived from smokers (one former light smoker, one current heavy smoker, and three current light smokers). Four of these patients had been treated with tyrosine kinase inhibitors and all had a partial response, with median overall survival (14.5 months) and median progression-free survival (6.8 months), being longer than in patients with similarly staged lung adenocarcinoma without EGFR mutation or treatment with tyrosine kinase inhibitors (6.8 and 3.1 months, respectively, according to data from an as yet unpublished study at our institution). CONCLUSION: This study provides further evidence that smoking status, include years of smoking and number of cigarettes smoked per day, plays an important role in EGFR mutation in patients with lung adenocarcinoma. Five of seven specimens with G719S/A or L861Q mutations coming from smokers indicates that there may be a relationship between G719S/A or L861Q mutation and smoking history. However, regardless of the influence of smoking, the effectiveness of tyrosine kinase inhibitors was satisfactory in four patients harboring G719S/A and L861Q EGFR mutation.