RNA polyadenylation is a key post-transcriptional modification essential for gene expression regulation. However, the role and mechanism of polyadenylation and its key molecule, polyadenylate binding protein nuclear 1 (PABPN1), in hepatocellular carcinoma (HCC) remain poorly understood. This study investigates the role of PABPN1 and its regulatory genes in HCC progression to identify potential therapeutic targets. Analysis of The Cancer Genome Atlas (TCGA) dataset and an independent HCC cohort revealed significant upregulation of PABPN1 in HCC patients, which correlates with poor prognosis. Loss-of-function studies using HCC cell lines and conditional knockout mouse models demonstrated that targeting PABPN1 inhibited HCC progression. Conversely, overexpression of PABPN1 promoted HCC development in vitro and in a hydrodynamic transfection hepatocarcinogenesis mouse model. Mechanistic investigations showed that PABPN1 modulates C5 mRNA polyadenylation and stability, with the PABPN1-C5 axis driving NF-κB activation and recruiting polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) to promote HCC progression. Therapeutic targeting of the PABPN1-C5 axis using the C5a receptor inhibitor CCX168 significantly inhibited HCC progression in both in vitro and in vivo models. This study identifies PABPN1 as a critical regulator of HCC development and sheds light on the post-transcriptional regulation of complement components in cancer. Targeting the PABPN1-C5 axis represents a promising strategy for HCC treatment.

Genome-wide association studies (GWAS) have identified numerous single-nucleotide polymorphisms (SNPs) associated with various diseases, including cancer. However, the mechanisms by which these SNPs contribute to disease susceptibility remain largely unclear. While recent studies have explored the transcriptional impact of disease-associated SNPs, their role in post-transcriptional regulation has been less extensively investigated. In this study, we investigated whether cancer-associated SNPs influence gene expression by altering N6-methyladenosine (m6A) RNA methylation. We collected GWAS-identified SNPs across nine cancer types and integrated these with matched tumor and normal m6A RNA immunoprecipitation sequencing (m6A-seq) and RNA sequencing (RNA-seq) datasets. We first identified differentially methylated m6A sites and assessed whether cancer-associated SNPs were enriched within these regions. These analyses revealed that cancer-associated SNPs were significantly enriched within hypermethylated m6A regions in colon cancer. Integrative analysis revealed that SNPs enriched in m6A-modified regions are associated with altered gene expression and RNA splicing, suggesting that m6A methylation mediates the post-transcriptional impact of genetic variants. Experimental validation further confirmed altered gene expression following ALKBH5 knockdown, consistent with patient-derived data. Collectively, our findings support a novel mechanistic connection between genetic variants and RNA methylation-driven transcriptomic regulation in colorectal cancer, underscoring the epitranscriptome as a potential axis of oncogenic control.

Mutations modification enzymes including the tRNA N 7 -methylguanosine (m 7 G) methyltransferase complex component WDR4 were frequently found in patients with neural disorders, while the pathogenic mechanism and therapeutic intervention strategies are poorly explored. In this study, we revealed that patient-derived WDR4 mutation leads to temporal and cell-type-specific neural degeneration, and directly causes neural developmental disorders in mice. Mechanistically, WDR4 point mutation disrupts the interaction between WDR4 and METTL1 and accelerates METTL1 protein degradation. We further uncovered that impaired tRNA m 7 G modification caused by Wdr4 mutation decreases the mRNA translation of genes involved in mTOR pathway, leading to elevated endoplasmic reticulum stress markers, and increases neural cell apoptosis. Importantly, treatment with stress-attenuating drug Tauroursodeoxycholate (TUDCA) significantly decreases neural cell death and improves neural functions of the Wdr4 mutated mice. Moreover, adeno-associated virus mediated transduction of wild-type WDR4 restores METTL1 protein level and tRNA m 7 G modification in the mouse brain, and achieves long-lasting therapeutic effect in Wdr4 mutated mice. Most importantly, we further demonstrated that both TUDCA treatment and WDR4 restoration significantly improve the survival and functions of human iPSCs-derived neuron stem cells that harbor the patient’s WDR4 mutation. Overall, our study uncovers molecular insights underlying WDR4 mutation in the pathogenesis of neural diseases and develops two promising therapeutic strategies for treatment of neural diseases caused by impaired tRNA modifications.

Mutations modification enzymes including the tRNA N-7-methylguanosine (m(7)G) methyltransferase complex component WDR4 were frequently found in patients with neural disorders, while the pathogenic mechanism and therapeutic intervention strategies are poorly explored. In this study, we revealed that patient-derived WDR4 mutation leads to temporal and cell-type-specific neural degeneration, and directly causes neural developmental disorders in mice. Mechanistically, WDR4 point mutation disrupts the interaction between WDR4 and METTL1 and accelerates METTL1 protein degradation. We further uncovered that impaired tRNA m7G modification caused by Wdr4 mutation decreases the mRNA translation of genes involved in mTOR pathway, leading to elevated endoplasmic reticulum stress markers, and increases neural cell apoptosis. Importantly, treatment with stress-attenuating drug Tauroursodeoxycholate (TUDCA) significantly decreases neural cell death and improves neural functions of the Wdr4 mutated mice. Moreover, adeno-associated virus mediated transduction of wild-type WDR4 restores METTL1 protein level and tRNA m(7)G modification in the mouse brain, and achieves long-lasting therapeutic effect in Wdr4 mutated mice. Most importantly, we further demonstrated that both TUDCA treatment and WDR4 restoration significantly improve the survival and functions of human iPSCs-derived neuron stem cells that harbor the patient's WDR4 mutation. Overall, our study uncovers molecular insights underlying WDR4 mutation in the pathogenesis of neural diseases and develops two promising therapeutic strategies for treatment of neural diseases caused by impaired tRNA modifications.

Aberrant RNA modifications are frequently associated with cancers, while the underlying mechanisms and clinical significance remain poorly understood. Here, we find that the ac4C RNA acetyltransferase NAT10 is significantly upregulated in esophageal cancers (ESCAs) and associated with poor ESCA prognosis. In addition, using ESCA cell lines and mouse models, we confirm the critical functions of NAT10 in promoting ESCA tumorigenesis and progression in vitro and in vivo. Mechanistically, NAT10 depletion reduces the abundance of ac4C-modified tRNAs and decreases the translation efficiencies of mRNAs enriched for ac4C-modified tRNA-decoded codons. We further identify EGFR as a key downstream target that facilitates NAT10's oncogenic functions. In terms of clinical significance, we demonstrate that NAT10 depletion and gefitinib treatment synergistically inhibit ESCA progression in vitro and in vivo. Our data indicate the mechanisms underlying ESCA progression at the layer of mRNA translation control and provide molecular insights for the development of effective cancer therapeutic strategies.

In clinical practice, we often observed that patients who underwent total thyroidectomy due to clinically involved nodal disease (cN1a) actually had less extensive CLNM on final pathology. This study investigates whether total thyroidectomy and therapeutic bilateral CND are necessary for all PTC patients with cN1a. This study retrospectively reviewed 899 PTC patients who underwent total thyroidectomy with bilateral CND from January 2012 to June 2017. The patients were divided into two groups according to pre-operative central lymph node (CLN) status: cN0, no suspicious CLNM; cN1a, suspicious CLNM. We compared the clinicopathological features of these two groups. There was no significant difference in recurrence between cN0 and cN1a groups after a mean follow-up time of 59.1 months. Unilateral cN1a was related to the largest central LN size ≥ 2 mm (OR = 3.67, p < 0.001) and number of CLNM > 5(OR = 2.24, p = 0.006). On the other hand, unilateral cN1a was not associated with an increased risk of contralateral lobe involvement (OR = 1.35, p = 0.364) and contralateral CLNM (OR = 1.31, p = 0.359). Among 106 unilateral cN1a patients, 33 (31.1%) were found to be pN0 or had ≤ 5 metastatic CLNs with the largest node smaller than 2 mm. Most cN1a patients were in an intermediate risk group for recurrence and required total thyroidectomy. However, lobectomy with CND should have performed in approximately 30% of the cN1a patients. Pre-operative clinical examination, meticulous radiologic evaluation, and intra-operative frozen sections to check the nodal status are prerequisites for this approach.

Mis-regulated RNA modifications promote the processing and translation of oncogenic mRNAs to facilitate cancer progression, while the molecular mechanisms remain unclear. Here we reveal that tRNA m7G methyltransferase complex proteins METTL1 and WDR4 are significantly up-regulated in esophageal squamous cell carcinoma (ESCC) tissues and associated with poor ESCC prognosis. In addition, METTL1 and WDR4 promote ESCC progression via the tRNA m7G methyltransferase activity in vitro and in vivo. Mechanistically, METTL1 or WDR4 knockdown leads to decreased expression of m7G-modified tRNAs and reduces the translation of a subset of oncogenic transcripts enriched in RPTOR/ULK1/autophagy pathway. Furthermore, ESCC models using Mettl1 conditional knockout and knockin mice uncover the essential function of METTL1 in promoting ESCC tumorigenesis in vivo. Our study demonstrates the important oncogenic function of mis-regulated tRNA m7G modification in ESCC, and suggest that targeting METTL1 and its downstream signaling axis could be a promising therapeutic target for ESCC treatment.

Background: The 2015 American Thyroid Association (ATA) guidelines recommend pursuing total thyroidectomy with therapeutic central lymph-node dissection (CND) in patients with clinically apparent nodal disease (cN1a), regardless of tumor size. The aim of this study was to investigate whether total thyroidectomy is necessary for thyroid papillary microcarcinoma (PTMC) patients with preoperative unilateral cN1a.Methods: This study included 295 papillary thyroid microcarcinoma patients who underwent total thyroidectomy with bilateral CND from January 2012 to June 2015. Results: The median follow-up time was 42.5 months. Locoregional recurrence (LRR) was observed in only two (0.9%) patients. Among 70 cN1a patients, only 19 (27.1%) were at intermediate risk for disease recurrence and required total thyroidectomy per the ATA guidelines. Lobectomy can be considered as a treatment option for the remaining patients (72.9%).Conclusions: Our study showed that more than two-thirds of PTMC patients with clinical nodal disease who underwent total thyroidectomy and CND were actually lobectomy candidates. Total thyroidectomy as the first surgical option for cN1a, especially in PTMC patients, should be reconsidered.(c) 2021 Published by Elsevier Inc.

Introduction Ropivacaine is widely used as a local analgesic, but it has toxicity that is related to the concentration, and highly concentrated ropivacaine can induce motor nerve blockage. Aim To investigate the safety of low-concentration pre-incisional ropivacaine injection for postoperative pain control and compare postoperative adverse events between a low-concentration ropivacaine injection group and a high-concentration ropivacaine injection group. Material and methods Patients who underwent thyroidectomy via the bilateral axillo-breast approach (BABA) between June 2017 and October 2021 performed by a single surgeon at Samsung Medical Center were retrospectively identified. These outcomes were compared between the two groups after 1 : 1 propensity score matching. Results From a total of 633 patients, 620 patients were selected. There were 527 in the low-concentration ropivacaine group and 93 in the high-concentration ropivacaine group. After propensity score matching, two comparable groups with 93 patients in each were obtained. The incidence of ropivacaine-related adverse events was similar between the two groups (p = 0.186) but the occurrence of postoperative bradycardia (p = 0.048) was lower in the low-concentration ropivacaine group than in the high-concentration ropivacaine group. Other outcomes such as postoperative pain scores (p = 0.363), postoperative nausea and vomiting (p > 0.999), and postoperative opioid consumption (p = 0.699) were similar between the two groups. Conclusions Pre-incisional low-concentration ropivacaine injection was effective for postoperative pain control and can be safely used in BABA thyroidectomy.

Background Telomerase reverse transcriptase (TERT) promoter mutations are associated with increased recurrence and mortality in patients with thyroid carcinoma. Previous studies on TERT promoter mutations were retrospectively conducted on a limited number of patients. Methods We prospectively collected data on all consecutive patients who underwent thyroid carcinoma surgery between January 2019 and December 2020 at the Samsung Medical Center, Seoul, Korea. We included 2,092 patients with thyroid carcinoma. Results Of 2,092 patients, 72 patients (3.4%) had TERT promoter mutations. However, the frequency of TERT promoter mutations was 0.5% in papillary thyroid microcarcinoma (PTMC) ≤1 cm and it was 5.8% in papillary thyroid carcinoma (PTC) >1 cm. The frequency of TERT promoter mutations was significantly associated with older age at diagnosis (odds ratio [OR], 1.12; P<0.001), larger primary tumor size (OR, 2.02; P<0.001), and aggressive histological type (OR, 7.78 in follicular thyroid carcinoma; OR, 10.33 in poorly differentiated thyroid carcinoma; OR, 45.92 in anaplastic thyroid carcinoma; P<0.001). Advanced T stage, advanced N stage, and distant metastasis at diagnosis were highly prevalent in mutated thyroid cancers. However, initial distant metastasis was not present in patients with TERT promoter mutations in PTMC. Although the C228T mutation was more highly detected than the C250T mutation (64 cases vs. 7 cases), there were no significant clinicopathological differences. Conclusion This study is the first attempt to investigate the frequency of TERT promoter mutations in a real-world setting. The frequency of TERT promoter mutations in PTC was lower than expected, and in PTMC, young patients, and female patients, the frequency was very low.

Background: This study was conducted to evaluate risk factors and long-term prognosis of contralateral central neck metastasis (CCNM) in papillary thyroid cancer (PTC) patients with ipsilateral lateral neck metastasis. We present clinical evidence to aid in surgical decision-making regarding the extent of central neck dissection (CND), focusing on separation between ipsilateral and contralateral sides. Methods: A total of 379 PTC patients who underwent total thyroidectomy and concomitant bilateral central neck dissection with ipsilateral lateral neck dissection (LND) at a single institution was retrospectively included between January 1997 and December 2015. Results: The median follow-up time was 83.2 months, the mean age was 44.3 years, and the mean tumor size was 1.5 cm. Among the study sample, 266 patients were female (70.2%) and 113 (29.8%) were male. Of 379 patients, CCNM was present in 34.6%. In multivariate analysis, male sex (adjusted OR = 2.46, p = 0.002), bilaterality (adjusted OR = 2.58, p = 0.004), number of metastatic ipsilateral central lymph nodes (adjusted OR = 1.15, p = 0.002), number of metastatic lateral lymph nodes (adjusted OR = 1.48, p < 0.001), and three-level metastasis (adjusted OR = 2.46, p = 0.012) were identified as risk factors of CCNM. Overall recurrence occurred in 6.0% and 11.5% of patients in the CCNM (-) group and CCNM (+) group, respectively. In addition, contralateral recurrence was observed in 1.2% patients and 0.8% patients in the CCNM (-) group and CCNM (+) group, respectively. However, CCNM did not significantly increase risk of recurrence (adjusted HR = 1.01, p = 0.981). Conclusions: Although the probability of pathological CCNM is not negligible, CCNM was not associated with higher risk of recurrence. This study suggest that central neck dissection may be limited to the ipsilateral side, and the result regarding prognosis of CCNM may help to avoid bilateral CND so that it could have potential to minimize unnecessary surgery-related complications such as recurrent laryngeal nerve(RLN) injury or hypoparathyroidism. (c) 2021 Elsevier Ltd, BASO -The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

Background: The actions of thyrotropin-binding inhibitory immunoglobulins (TBIIs) against thyrotropin receptors in thyroid follicular cells have been studied as important etiological factors in Graves' disease (GD). The purpose of this study was to investigate changes in the TBII levels of patients undergoing total thyroidectomy (TTx) or radioactive iodine (RAI) therapy for GD refractory to antithyroid drugs (ATDs). Methods: We enrolled patients who underwent TTx or RAI for GD with previous ATD use between January 2011 and December 2017 at the Samsung Medical Center in Seoul, Korea. Thorough retrospective reviews of medical records were performed in 130 patients. Results: Patients with goiter, ophthalmopathy, high levels of TBIIs, and high doses of ATDs received TTx. Elderly patients with arrhythmia received RAI. We observed that TBII levels continued to decrease after TTx. On the contrary, TBIIs initially increased for 138 days (estimated median time) and then decreased slowly after RAI. A faster decline in TBII levels was observed in the TTx group than in the RAI group (p < 0.001). The estimated median time for TBIIs to decrease below 4.5 IU (3 × upper normal limit, which is known to be a risk factor for fetal hyperthyroidism) was 318 days in the TTx group and 659 days in the RAI group, respectively. In the RAI group, high levels of TBII (>4.5 IU/L) were present in 70 (82%) at 6 months, 57 (67%) at 1 year, and 3 (3%) at 2 years. In the TTx group, rapid decreases in TBII levels were observed in younger patients and those with lower baseline TBII levels. In the RAI group, smaller thyroid volume was correlated with more rapid decrease in TBII levels. Conclusions: The changes in TBII levels following TTx or RAI were different in patients with refractory GD. When deciding on TTx or RAI, this difference should be considered with patient age, severity of hyperthyroidism, goiter, ophthalmopathy, and future pregnancy plans (for young female patients).

Post-transcriptional regulation is an indispensable cellular mechanism of gene expression control that dictates various cellular functions and cell fate decisions. Recently, various chemical RNA modifications, termed the "epitranscriptome," have been proposed to play crucial roles in the regulation of post-transcriptional gene expression. To date, more than 170 RNA modifications have been identified in almost all types of RNA. As with DNA modification-mediated control of gene expression, regulation of gene expression via RNA modification is also accomplished by three groups of proteins: writers, readers, and erasers. Several emerging studies have revealed that dysregulation in RNA modification is closely associated with tumorigenesis. Notably, the molecular outcomes of specific RNA modifications often have opposite cellular consequences. In this review, we highlight the current progress in the elucidation of the mechanisms of cancer development due to chemical modifications of various RNA species.

BACKGROUND:Surgery is the most important curative treatment for medullary thyroid carcinoma (MTC). The relationship between surgeon volume (the number of surgeries performed) and short-term surgical outcomes, such as increased postoperative complication or costs, is well established. This study evaluated whether surgeon volume influenced long-term oncologic outcomes.METHODS:We retrospectively reviewed 246 patients diagnosed with MTC after initial thyroid surgery from 1995 to 2019. After exclusion, 194 patients were eligible for inclusion in the study. Surgeons were categorized as low/intermediate volume (fewer than 100 operations per year) or high volume (at least 100 operations per year).RESULTS:Of the 194 included patients, 60 (30.9%) developed disease recurrence, and 9 (4.6%) died of MTC during the median follow-up of 92.5 months. Having a low/intermediate-volume surgeon was associated with high disease recurrence (log-rank test, p < 0.001). After adjustment for age, sex, tumor type (sporadic versus hereditary), primary tumor size, presence of central lymph node metastasis (LNM), presence of lateral LNM, extrathyroidal extension, and positive resection margin, surgeon volume was a significant factor for disease recurrence (hazard ratio 2.28, p = 0.004); however, cancer-specific survival was not affected by surgeon volume (hazard ratio 4.16, p = 0.115).CONCLUSIONS:Surgeon volume is associated with long-term oncologic outcome. MTC patients will be able to make the best decisions for their treatment based on the results of this study.

The mRNA N-6-methyladenosine (m(6)A) modification has emerged as an essential regulator of normal and malignant hematopoiesis. Inactivation of the m(6)A mRNA reader YTHDF2, which recognizes m(6)A-modified transcripts to promote m(6)A-mRNA degradation, results in hematopoietic stem cell (HSC) expansion and compromises acute myeloid leukemia. Here we investigate the long-term impact of YTHDF2 deletion on HSC maintenance and multilineage hematopoiesis. We demonstrate that Ythdf2-deficient HSCs from young mice fail upon serial transplantation, display increased abundance of multiple m(6)A-modified inflammation-related transcripts, and chronically activate proinflammatory pathways. Consistent with the detrimental consequences of chronic activation of inflammatory pathways in HSCs, hematopoiesis-specific Ythdf2 deficiency results in a progressive myeloid bias, loss of lymphoid potential, HSC expansion, and failure of aged Ythdf2-deficient HSCs to reconstitute multilineage hematopoiesis. Experimentally induced inflammation increases YTHDF2 expression, and YTHDF2 is required to protect HSCs from this insult. Thus, our study positions YTHDF2 as a repressor of inflammatory pathways in HSCs and highlights the significance of m(6)A in long-term HSC maintenance.

, The mRNA N 6 -methyladenosine (m 6 A) modification has emerged as an essential regulator of normal and malignant hematopoiesis. Inactivation of the m 6 A mRNA reader YTHDF2, which recognizes m 6 A-modified transcripts to promote m 6 A-mRNA degradation, results in hematopoietic stem cell (HSC) expansion and compromises acute myeloid leukemia. Here we investigate the long-term impact of YTHDF2 deletion on HSC maintenance and multilineage hematopoiesis. We demonstrate that Ythdf2 -deficient HSCs from young mice fail upon serial transplantation, display increased abundance of multiple m 6 A-modified inflammation-related transcripts, and chronically activate proinflammatory pathways. Consistent with the detrimental consequences of chronic activation of inflammatory pathways in HSCs, hematopoiesis-specific Ythdf2 deficiency results in a progressive myeloid bias, loss of lymphoid potential, HSC expansion, and failure of aged Ythdf2 -deficient HSCs to reconstitute multilineage hematopoiesis. Experimentally induced inflammation increases YTHDF2 expression, and YTHDF2 is required to protect HSCs from this insult. Thus, our study positions YTHDF2 as a repressor of inflammatory pathways in HSCs

Purpose: Post-thyroidectomy bleeding (PTB) is rare but may be a life-threatening complication.This study investigated the incidence of and risk factors for postoperative bleeding after thyroid surgery.Methods: The medical records of all patients who underwent thyroidectomy at Samsung Medical Center between November 1994 and July 2018 were reviewed retrospectively to identify any risk factors for PTB.Clinicopathological factors related to post-thyroidectomy bleeding were included in our analysis, and the association of potential risk factors with outcomes was tested by logistic regression analysis.Results: Of 19,657 patients, PTB occurred in 132 (0.67%).In addition, 130 cases of PTB had emerged within 24 hours, while only 2 patients required re-operation after discharge.One patient expired due to hypoxic brain damage.A univariate analysis revealed that male sex (odds ratio [OR]=2.28,P<0.0001), chronic kidney disease (OR=5.26,P=0.02), the use of antihemorrhagic agents (OR=0.57,P=0.0017), and surgeon-specific factors (OR=3.4,P<0.0001) were significantly associated with PTB.However, upon multivariate analysis, only male sex (OR=2.34,P<0.0001) and surgeon-specific factors (OR=3.10,P<0.0001) were significant risk factors for PTB.Conclusion: Male sex and surgeon-related factors significantly increased the risk of PTB.Since our study showed a tendency for PTB to increase within 24 hours of surgery, surgeons should look through whole surgical process or surgical techniques to minimize bleeding during the operation and conduct a close observation of all patients immediately after surgery.

N6-methyladenosine (m6A), the most prevalent chemical modification found on eukaryotic mRNA, is associated with almost all stages of mRNA metabolism and influences various human diseases. Recent research has implicated the aberrant regulation of m6A mRNA modification in many human cancers. An increasing number of studies have revealed that dysregulation of m6A-containing gene expression via the abnormal expression of m6A methyltransferases, demethylases, or reader proteins is closely associated with tumorigenicity. Notably, the molecular functions and cellular consequences of m6A mRNA modification often show opposite results depending on the degree of m6A modification in specific mRNA. In this review, we highlight the current progress on the underlying mechanisms of m6A modification in mRNA metabolism, particularly the functions of m6A writers, erasers, and readers in the context of tumorigenesis.

N6-Methyladenosine (m6A), the most prevalent internal modification associated with eukaryotic mRNAs, influences many steps of mRNA metabolism, including splicing, export, and translation, as well as stability. Recent studies have revealed that m6A-containing mRNAs undergo one of two distinct pathways of rapid degradation: deadenylation via the YT521-B homology (YTH) domain-containing family protein 2 (YTHDF2; an m6A reader protein)-CCR4/NOT (deadenylase) complex or endoribonucleolytic cleavage by the YTHDF2-HRSP12-ribonuclease (RNase) P/mitochondrial RNA-processing (MRP) (endoribonuclease) complex. Some m6A-containing circular RNAs (circRNAs) are also subject to endoribonucleolytic cleavage by YTHDF2-HRSP12-RNase P/MRP. Here, we highlight recent progress on the molecular mechanisms underlying rapid mRNA degradation via m6A and describe our current understanding of the dynamic regulation of m6A-mediated mRNA decay through the crosstalk between m6A (or YTHDF2) and other cellular factors.