METTL3-mediated m6A modification of STEAP2 mRNA inhibits papillary thyroid cancer progress by blocking the Hedgehog signaling pathway and epithelial-to-mesenchymal transition.

Papillary thyroid cancer (PTC) is a common endocrine system malignancy all over the world. Aberrant expression of six transmembrane epithelial antigen of the prostate 2 (STEAP2) has been functionally associated with cancer progression in many cancers. Nevertheless, its biological function in PTC is still unclear. Here, we found that PTC tissues had preferentially downregulated STEAP2 as compared with noncancerous tissues. Low STEAP2 expression correlated with aggressive clinicopathological characteristics and dismal prognosis in patients with PTC. We performed gain- and loss-of-function experiments, including cell proliferation assay (Cell Counting Kit-8 assay), EdU (5-ethynyl-2'-deoxyuridine) and colony formation assays, transwell migration, and invasion assays, and constructed a nude mouse xenograft tumor model. The results demonstrated that STEAP2 overexpression inhibited PTC cell proliferation, migration, and invasion in vitro and inhibited lung metastasis and tumorigenicity in vivo. Conversely, silencing STEAP2 yielded the opposite results in vitro. Mechanistically, bioinformatics analysis combined with validation experiments identified STEAP2 as the downstream target of methyltransferase-like 3 (METTL3)-mediated N6-methyladenosine (m6A) modification. METTL3 stabilized STEAP2 mRNA and regulated STEAP2 expression positively in an m6A-dependent manner. We also showed that m6A-mediated STEAP2 mRNA translation initiation relied on a pathway dependent on the m6A reader protein YTHDF1. Rescue experiments revealed that silencing STEAP2 partially rescued the tumor-suppressive phenotype induced by METTL3 overexpression. Lastly, we verified that the METTL3-STEAP2 axis functions as an inhibitor in PTC by suppressing epithelial-mesenchymal transition and the Hedgehog signaling pathway. Taken together, these findings strongly suggest that METTL3-mediated STEAP2 m6A modification plays a critical tumor-suppressive role in PTC progression. The METTL3-STEAP2 axis may be a potential therapeutic molecular target against PTC.

Circular RNA_0057209 Acts as ceRNA to Inhibit Thyroid Cancer Progression by Promoting the STK4-Mediated Hippo Pathway via Sponging MicroRNA-183.

Thyroid cancer is the most common malignancy of the endocrine system, and its outcome remains unsatisfactory. In recent years, circular RNAs (circRNAs) have emerged as crucial regulators in cancers. In the current study, we aimed to investigate whether and how circRNA_0057209 functioned in thyroid cancer. Initial results revealed that circRNA_0057209 and STK4 were both reduced, while miR-183 was up-regulated in thyroid cancer tissues and cells. Experiments including RNA pull-down and RIP assays further identified that upregulation of circRNA_0057209 augmented the expression of STK4, a target gene of miR-183, by competitively-binding to miR-183. Furthermore, functional experiments provided evidence that overexpression of circRNA_0057209 not only inhibited the proliferative, migratory, and invasive properties of thyroid cancer cells while facilitating their apoptosis but also delayed tumor growth. Conversely, upregulation of miR-183 or silencing of STK4 reversed the changes induced by circRNA_0057209. Meanwhile, mechanistic experimentation demonstrated that circRNA_0057209 promoted STK4 expression by sponging miR-183, while STK4 enhanced YAP phosphorylation to mediate the Hippo pathway, thereby suppressing tumor progression. Altogether, our findings indicated that circRNA_0057209 may serve as a competing endogenous RNA of miR-183 to increase STK4 expression, thus inhibiting the development of thyroid cancer.

METTL3-Induced miR-222-3p Upregulation Inhibits STK4 and Promotes the Malignant Behaviors of Thyroid Carcinoma Cells.

CONTEXT: Abnormally high expression of N6-methyladenosine (m6A) methyltransferase-like 3 (METTL3) has been implied to accompany thyroid carcinoma (TC) development. OBJECTIVE: This study aimed to explore the protumorigenic role and downstream signaling axis of METTL3 in TC. METHODS: This study was conducted at the Sun Yat-Sen Memorial Hospital Sun Yat-Sen University. METTL3 and miR-222-3p were overexpressed or downregulated in TC cells. Tumor and adjacent normal tissues were collected from 80 patients (19 men and 60 women, aged 30-70 years) with a pathological diagnosis of TC from January 2012 to January 2015. Cells were classified and subjected to different treatments. The expression of METTL3 was validated in TC tissues and cell lines. In functional studies, METTL3 and miR-222-3p were overexpressed or downregulated in TC cells to evaluate their effects on malignant behaviors, which were subsequently verified by xenografts in nude mice. RESULTS: The expression of METTL3 was elevated in TC, correlating with poor prognosis of TC patients. Heightened METTL3 expression accelerated malignant behaviors of TC cells. Mechanistically, METTL3 stimulated miR-222-3p expression by mediating the m6A modification of pri-miR-222-3p. miR-222-3p targeted and inversely regulated serine/threonine stress kinase 4 (STK4). Knockdown of METTL3 augmented STK4 expression by downregulating miR-222-3p, thereby suppressing the malignant behaviors of TC cells as well as tumor growth and lung metastasis in nude mice. CONCLUSION: Silencing METTL3 suppresses miR-222-3p expression and thus stimulates STK4 expression, thereby repressing the malignancy and metastasis of TC.

ß-Catenin/LEF-1 transcription complex is responsible for the transcriptional activation of LINC01278.

BACKGROUND: Our previous study shows that LINC01278 inhibits the malignant proliferation and invasion of papillary thyroid carcinoma (PTC) cells by regulating the miR-376c-3p/DNM3 axis. However, the regulation mechanism of LINC01278 expression in PTC cells is still unclear. METHODS: The luciferase reporter and ChIP assays were used to confirm the binding of LEF-1 to the putative promoter site of LINC01278 gene. The RNA immunoprecipitation and RNA pulldown were used to determine the enrichment of LINC01278 in ß-catenin protein. The proteasome inhibitors (MG132) was used for detecting the ß-catenin ubiquitination-proteasome degradation. Wnt/ß-catenin specific agonists (LiCI), inhibitors (WiKI4) and TOP/FOP-flash reporter assay were used for detecting the activation of Wnt/ß-catenin signal. Western blot was used to detected the expression of target proteins. RESULTS: The online PROMO algorithm determines a putative LEF-1 binding site on LINC01278 promoter, the LEF-1 binds to the putative promoter site of LINC01278 gene, and ß-catenin enhances the binding of LEF-1 to the LINC01278 gene promoter. Furthermore, LINC01278 negatively regulated the protein accumulation of ß-catenin in the cytoplasm, into nucleus, and ultimately inhibited the transcription of downstream target genes activated by Wnt/ß-catenin signal. The results of RNA immunoprecipitation and RNA pulldown proved the direct binding of LINC01278 to ß-catenin protein. In addition, the combination of LINC01278 and ß-catenin promotes the ß-catenin ubiquitination-proteasome degradation. CONCLUSION: In summary, we found the transcriptional activation of LINC01278 by the ß-catenin/LEF-1 transcription factor, and the negative feedback regulation of LINC01278 onß-catenin signal.

LncRNA-HCG18 regulates the viability, apoptosis, migration, invasion and epithelial-mesenchymal transition of papillary thyroid cancer cells via regulating the miR-106a-5p/PPP2R2A axis.

The incidence of papillary thyroid cancer (PTC) has experienced a rapid increase in recent years. Long non-coding RNA-homo sapiens HLA complex group (HCG) 18 plays a regulatory role in cancers, but its role in PTC remained unknown. This study determined the expressions of HCG18, microRNA (miR)-106a-5p, and protein phosphatase 2 regulatory subunit B alpha (PPP2R2A) in PTC tissues and cells by qRT-PCR. ENCORI predicted the targeting relation between HCG18 and miR-106a-5p. TargetScan v7.2 predicted the targeting relation between miR-106a-5p and PPP2R2A. Dual-luciferase reporter assay was performed to validate the two targeting relations. The viability, migration, and invasion of PTC cells were detected by Cell Counting Kit-8, wound healing assay, and Transwell assay, respectively. The expressions of matrix metalloproteinase 2 (MMP-2), MMP-9, E-cadherin, N-cadherin, and Vimentin in TPC-1 and MDA-T68 cells were assessed by qRT-PCR and Western blot. It was found that HCG18 was down-regulated in PTC. Overexpressing HCG18 suppressed viability, migration, and invasion, promoted apoptosis, and inhibited miR-106a-5p expression in PTC cells. HCG18 interacted with miR-106a-5p, the expression of which was upregulated in PTC. Upregulating miR-106a-5p expression by lentivirus infection promoted viability, migration and invasion and inhibited apoptosis of PTC cells, reversed the effect of HCG18 on the biological behaviors of PTC cells, and promoted the expressions of MMP-2, MMP-9, E-cadherin, and Vimentin and downregulated E-cadherin expression in PTC cells. PPP2R2A, a direct target of miR-106a-5p, was downregulated in PTC, and HCG18 promoted PPP2R2A expression in PTC cells by sponging miR-106a-5p. Furthermore, PPP2R2A reversed the effects of miR-106a-5p on PTC cells. In conclusion, HCG18 suppressed viability, migration, invasion and epithelial-mesenchymal transition and promoted apoptosis of PTC cells via regulating the miR-106a-5p/PPP2R2A axis.

Comprehensive circular RNA profiling reveals the regulatory role of circRNA_0007694 in papillary thyroid carcinoma.

PURPOSE: The present study aimed to identify differentially expressed circRNAs in thyroid cancer and verify their potential functions. METHODS: Next-generation sequencing was used to identify differentially expressed circRNAs between papillary thyroid carcinoma (PTC) tissues and paired pericarcinomatous tissues. Polymerase chain reaction and Sanger sequencing methods successfully identified hsa_circ_0007694. A hsa_circ_0007694 over-expression vector was prepared to determine the effect of this circRNA on proliferation, migration, invasion, apoptosis, and the cell cycle in PTC cells. An in vivo animal assay was conducted by injecting PTC cells into the chests of mice. Further, RNA-seq was performed, followed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, to verify the regulatory mechanism of hsa_circ_0007694. Western blotting was used to verify the genes thought to be involved in the hsa_circ_0007694 regulatory pathways based on KEGG analysis. RESULTS: We identified a circRNA, hsa_circ_0007694 that was down-regulated in PTC tissues compared to pericarcinomatous tissues. Over-expression of hsa_circ_0007694 promoted apoptosis and inhibited proliferation, migration, and invasion in PTC cells in vitro, and decreased tumor growth in vivo. Transcriptome sequence analysis suggested 129 differentially expressed genes between PTC tissue and paired pericarcinomatous tissue. KEGG analysis and western blotting indicated that the PI3K/AKT/mTOR and Wnt signaling networks are most likely to be related to hsa_circ_0007694 in thyroid cancer. CONCLUSION: The circRNA hsa_circ_0007694 is down-regulated in PTC and is therefore a potential therapeutic target.

Lysine-Specific Demethylase 1 Affects the Progression of Papillary Thyroid Carcinoma via HIF1α and microRNA-146a.

CONTEXT: Lysine-specific demethylase 1 (LSD1) stabilizes hypoxia-inducible factor 1α (HIF1α) to advance tumor progression, while HIF1α functions as a transcription factor to increase the expression of microRNA-146a (miR-146a). OBJECTIVE: We aim to investigate whether LSD1 affects the development of papillary thyroid carcinoma (PTC) via HIF1α and miR-146a. DESIGN: In vitro assays were performed with Nthy-ori 3-1, BHP5-16, BCPAP, K1, and BHP2-7 cell lines. In vivo assays were conducted with established xenograft tumors in nude mice. SETTING: This study was conducted at our lab. PATIENTS AND MATERIALS: PTC tissues and corresponding adjacent normal tissues were obtained from 45 patients hospitalized in Sun Yat-Sen Memorial Hospital. Assays were conducted using Nthy-ori 3-1, BHP5-16, BCPAP, K1, and BHP2-7 cell lines, as well as 50 male BALB/c nude mice. INTERVENTION: Cells were transfected with sh-LSD1, sh-GABPA, oe-LSD1, oe-HIF1α, miR-146a mimic, and miR-146a inhibitor. In addition, K1 cells expressing lv-oe-LSD1, lv-miR-146a inhibitor, lv-oe-LSD1 or miR-146a inhibitor were injected into the right side of the mice. LSD1 gene and protein expression patterns were analyzed in 45 clinical PTC tissue samples. MAIN OUTCOME MEASURE: Expression of LSD1, HIF1α, miR-146a, and GA-binding protein transcription factor alpha (GABPA), as well as their effects on PTC. RESULTS: LSD1 was highly expressed in clinical PTC tissues. LSD1 stabilized HIF1α and inhibited the degradation of its ubiquitin proteasome. HIF1α was enriched in the promoter region of miR-146a, an upregulated miRNA in PTC. HIF1α increased miR-146a expression to promote PTC progression in vitro, which was achieved by inhibiting GABPA, a target gene of miR-146a. LSD1 upregulated miR-146a to enhance the development and metastasis of PTC in nude mice. CONCLUSION: Our results show that LSD1 functions as an oncogene in PTC by upregulating HIF1α and miR-146a, elucidating an understanding of undefined mechanisms associated with tumor progression in PTC.

Long non-coding RNA TNRC6C-AS1 promotes methylation of STK4 to inhibit thyroid carcinoma cell apoptosis and autophagy via Hippo signalling pathway.

The role of long non-coding RNAs (lncRNAs) in thyroid carcinoma (TC), the most frequent endocrine malignancy, has been extensively examined. This study investigated effect of interaction among lncRNA TNRC6C-AS1, serine/threonine-protein kinase 4 (STK4) and Hippo signalling pathway on TC. Initially, lncRNA TNRC6C-AS1 expression in TC tissues was detected. To explore roles of lncRNA TNRC6C-AS1, STK4 and Hippo signalling pathway in TC progression, their expressions were altered. Interaction between lncRNA TNRC6C-AS1 and STK4, STK4 promoter methylation, or Hippo signalling pathway was verified. After that, a series of experiments were employed to evaluate in vitro ability of apoptosis, proliferation and autophagy of TC cells and in vivo tumorigenicity, and tumour growth of TC cells. lncRNA TNRC6C-AS1 was highly expressed while STK4 was poorly expressed in TC tissues. LncRNA TNRC6C-AS1 promoted the STK4 methylation and down-regulated STK4 expression, which further activated the Hippo signalling pathway. STK4 silencing was observed to promote the proliferation ability of TC cells, inhibit the apoptosis and autophagy abilities, as well as enhance the tumorigenicity and tumour growth. Moreover, the in vitro proliferation ability as well as the in vivo tumorigenicity and tumour growth of TC cells were inhibited after the blockade of Hippo signalling pathway, while the apoptosis and autophagy abilities were promoted. The results demonstrate that the lncRNA TNRC6C-AS1 increases STK4 promoter methylation to down-regulate STK4 expression, thereby promoting the development of TC through activation of Hippo signalling pathway. It highlights that lncRNA TNRC6C-AS1 may be a novel therapeutic target for the treatment of TC.

Linc01278 inhibits the development of papillary thyroid carcinoma by regulating miR-376c-3p/DNM3 axis.

PURPOSE: Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy, and its incidence has continuously increased in recent years. Therefore, it is essential to develop more useful therapeutic strategies. METHODS: We collected 56 pairs of PTC tissues and adjacent normal tissues and determined the expression patterns of linc01278, miR-376c-3p and DNM3. In addition, we analyzed the relationship between linc01278 expression and pathological information of PTC patients. Furthermore, the effects of linc01278, miR-376c-3p and DNM3 overexpression on proliferation, clonality, apoptosis, migration and invasion of PTC cell lines TPC1 and BCPAP were evaluated. The dual luciferase reporter assay was used to confirm the direct interaction between miR-376c-3p and linc01278. RESULTS: Linc01278 and DNM3 were remarkably down-regulated in PTC tissues and cell lines, whereas miR-376c-3p was significantly up-regulated. In addition, lower linc01278 expression was associated with increased tumor size, lymph node metastasis and higher clinical stage. Linc01278 inhibited cell proliferation of PTC cells by inducing apoptosis, and demonstrated attenuating effects on migration and invasion abilities of PTC cells by regulating the EMT process. More importantly, dual luciferase reporter experiments demonstrated the direct interaction between miR-376c-3p and linc01278, which revealed that DNM3 was a novel target of miR-376c-3p. The miR-376c-3p mimic significantly promoted the proliferation, migration and invasion of PTC cells, and inhibited cell apoptosis. Overexpression of DNM3 abolished the effects of the miR-376c-3p mimic on PTC cells. DNM3 expression was negatively correlated with miR-376c-3p expression, but was positively correlated with linc01278 expression. CONCLUSION: Overall, we found that linc01278 can act as a competing endogenous RNA (ceRNA) to sponge miR-376c-3p, thereby positively regulating DNM3 expression and ultimately acting as a tumor suppressor gene in PTC progression.

International normalized ratio on admission predicts the 90-day mortality of critically ill patients undergoing endarterectomy.

The association of the international normalized ratio (INR) with the long-term clinical outcome of patients who undergo endarterectomy has not yet been studied. The present study therefore primarily aimed to evaluate the association of INR on admission with the 90-day mortality of critically ill patients who underwent endarterectomy during hospitalization. The Medical Information Mart for Intensive Care III database was queried for patients undergoing endarterectomy. The 90-day mortality of patients was selected as a primary endpoint. Receiver-operating characteristic (ROC) curves were plotted to present the accuracy of predictions. Kaplan-Meier curves and multivariate Cox regression analysis were performed to analyse associations. Propensity score matching (PSM) was also conducted to reduce confounding bias. A total of 230 patients were included, with 36 90-day non-survivors. Patients with a high INR (≥1.5) on admission exhibited a higher 90-day mortality than those with a low INR (<1.5; 29.09 vs. 11.43%; P=0.003). The ROC area under the curve value was 0.687 [95% confidence interval (CI), 0.571-0.780]. Kaplan-Meier plots identified divergence in survival between patients with different INR levels (log-rank test, P=0.0013). The results of the multivariate Cox regression analysis indicated that a high INR level was significantly associated with 90-day mortality (hazard ratio, 2.19; 95% CI, 1.08-4.45; P=0.0305). Analysis of the PSM cohort presented similar results. In conclusion, the INR levels of critically ill patients who undergo endarterectomy may be used to stratify their risk of 90-day mortality.

Oncogenic Ras/squamous cell carcinoma antigen signaling pathway activation promotes invasiveness and lymph node metastases in papillary thyroid carcinoma.

Papillary thyroid carcinoma (PTC) is a type of cancer with one of the fastest increasing incidences worldwide. However, the therapeutic choices for PTC patients are limited and it is critical to further understand the molecular pathology underlying this disease. Squamous cell carcinoma antigens (SCCAs) are overexpressed in many tumors and participate in tumorigenesis. However, their roles in PTC are incompletely understood. Therefore, this study investigated the role of SCCA in PTC, evaluating its expression, its clinical implications and prognostic significance in PTC patient samples, as well as its function in vitro and in vivo, using a thyroid cancer cell line in which SCCA levels have been knocked down or overexpressed. In this study, SCCA expression levels were measured by immunohistochemistry (IHC) in non­cancerous and tumor tissues. Kaplan­Meier analyses assessed the survival in PTC patients. MTT assay, western blot analysis, invasion assay and xenograft tumor assay were used to calculate cell proliferation, migration, invasion and tumor growth. Our results showed that SCCA was overexpressed in PTC tissues and was correlated with the clinical stage of PTC. Patients with high SCCA expression had lower overall survival (OS), disease­free survival (DFS), lymph node recurrence­free survival (LNRFS), and distant recurrence­free survival (DRFS), compared to patients expressing low level of the SCCA protein. SCCA knockdown suppressed thyroid cancer cell proliferation, invasion and reduced xenograft tumor growth, whereas SCCA overexpression increased cell proliferation, invasion and xenograft tumor growth. Mechanistically, the activation of Ras increased SCCA expression, and SCCA expression was positively correlated with Ras levels in the PTC tissues. In conclusion, SCCA protein is overexpressed in PTC and may represent a predictive prognostic factor for PTC patients. Furthermore, activation of the Ras/SCCA pathway plays an important role in promoting tumor growth, invasion and metastasis in PTC.

Effect of neurological monitoring in postoperative 5-15 days residual thyroidectomy after primary thyroid cancer surgery.

AIM: To explore the application of intraoperative neurological monitoring in residual thyroidectomy 5-15 days after thyroid cancer operation and the influence on postoperative serum thyroglobulin (Tg), recurrent laryngeal nerve and function of parathyroid glands. METHODS: Material of patients receiving thyroid surgery from January 2010 to December 2016 was retrospectively analyzed. Cases meeting with standards were enrolled for analysis and the patients were divided into neurological monitoring group and non-neurological monitoring group in line with the use of neurological monitoring during the operation. Recurrent laryngeal nerve-injured hoarseness, hypoparathyroidism and concentration of serum Tg before and after the surgery were collected and analyzed. RESULTS: Four-hundred and thirty-five patients met with standards, among which 227 from neurological monitoring group and 208 from non-neurological monitoring group. Temporary hoarseness rate of non-neurological monitoring group and neurological monitoring group was 8.67% and 2.2%. Permanent hoarseness rate of non-neurological monitoring group and neurological monitoring group was 1.92% and 0.44%. Temporary hypoparathyroidism rate of non-neurological monitoring group and neurological monitoring group was 18.75% and 7.48%. Permanent hypoparathyroidism rate of non-neurological monitoring group and neurological monitoring group was 1.92% and 0.88%. Average Tg concentration 1 month after the surgery in non-neurological monitoring group and neurological monitoring group was 2.82 and 1.37 ng/mL, respectively. Rate of average Tg concentration less than 1 ng/mL 1 month after the surgery in non-neurological monitoring group and neurological monitoring group was 45.06% and 67.4%. CONCLUSION: Intraoperative neurological monitoring can be adopted in residual thyroidectomy in postoperative 5-15 days after primary thyroid cancer surgery, as to reduce incidence rate of recurrent laryngeal nerve injury and hypoparathyroidism and to enhance thorough removal of thyroid tissues and cancer tissues.

Activation of the ROCK1/MMP-9 pathway is associated with the invasion and poor prognosis in papillary thyroid carcinoma.

Rho-associated protein kinase 1 (ROCK1), a serine/threonine kinase, has previously been shown to be over-expressed in various types of human malignant tumors and to play an important role in cancer development and progression. Although ROCK1 has gained growing prominence as an important protein kinase in cancer biology, its potential as a predictive biomarker and a therapeutic target in papillary thyroid carcinoma (PTC) remains unknown. In the present study, ROCK1 expression was examined in 356 formalin-fixed, paraffin-embedded papillary thyroid carcinoma tissues using immunohistochemistry, and its clinical implications and prognostic significance were analyzed. Our results showed that ROCK1 expression was significantly increased in PTC compared with normal tissues, and was significantly associated with tumor size, lymphatic metastasis, distant organ metastasis, extrathyroid invasion, vascular invasion and tumor, node and metastasis (TNM) stage. Patients with strong ROCK1 expression had lower overall survival, disease-free survival, lymph node recurrence-free survival and distant recurrence-free survival rates than those with weak expression. Furthermore, overexpression of ROCK1 in papillary thyroid carcinoma cells was found to increase their invasiveness. Silencing ROCK1 by siRNA, however, caused an inhibition of cell invasion. Knockdown of ROCK1 decreased the volume and weight of the xenograft tumors, while overexpression of ROCK1 showed a proliferative tendency with significantly greater tumor volume and weight in vivo. Moreover, the upregulation of ROCK1 increased the expression of MMP-9, and levels of MMP-9 positively correlated with the ROCK1 levels in PTC tissues, implicating that MMP-9 may be involved in the mechanism of ROCK1 in the development and progression of PTC. These data suggest that ROCK1 might be a potential prognostic marker and therapeutic target for the treatment of PTC.

CHI3L1 overexpression is associated with metastasis and is an indicator of poor prognosis in papillary thyroid carcinoma.

OBJECTIVE: In this study, we examined the relationships between the expression level of CHI3L1 and the clinicopathological characteristics of papillary thyroid carcinoma. METHODS: A total of 322 tissue samples from patients with papillary thyroid carcinoma were collected, and the CHI3L1 expression levels in tumor tissues, matched adjacent noncancerous tissues were detected using immunohistochemistry (IHC) and qRT-PCR. The relationships between CHI3L1 expression levels and the clinical characteristics were evaluated. RESULTS: CHI3L1 expression was significantly increased in papillary thyroid carcinoma compared with matched adjacent noncancerous tissues (P< 0.001), tumor tissues with lymph node metastasis (LNM) compared with tumor tissues without LNM (P< 0.001) and tumor tissues with distant organ metastasis (DOM) compared with tumor tissues without DOM (P< 0.01). CHI3L1 expression was significantly associated with tumor size (P= 0.0001), lymph node metastasis (P< 0.0001), distant organ metastasis (P< 0.0001), extrathyroid invasion (P= 0.0022), vascular invasion (P= 0.0004) and TNM stage (P= 0.0001). CHI3L1 overexpression in papillary thyroid carcinoma tissues correlates with the tumor malignant potential (P< 0.01). More importantly, Cox multifactor analysis indicated that patients with high CHI3L1 expression have lower overall survival, disease-free survival, lymph node recurrence-free survival, and distant recurrence free survival rates than those with low expression (P< 0.05). And our findings were further validated by online Oncomine database. CONCLUSIONS: CHI3L1 is associated with tumor metastasis and might be a prognostic biomarker for papillary thyroid carcinoma.

Radical nerve dissection for the carcinoma of head of pancreas: report of 30 cases.

OBJECTIVE: To explore the clinical value of the radical nerve dissection (RND) for the carcinoma of head of pancreas (CHP). METHODS: The clinical and pathological data of 30 CHP patients who underwent RND in our hospital were retrospectively analyzed, with an attempt to explore the safety and short-term efficacy of this procedure. RESULTS: Among these 30 patients, the operative time was (351±61) min, the intra-operative blood loss was 350 (range, 300-600) mL, and the grades B and C pancreatic fistula was 23.33%. During the follow-up (range, 2-30 months; median: 17 months), the 1-year survival rate was 63.33% and the 1-year disease-free survival rate was 56.67%. Among the 23 patients (76.66%) with positive extra-pancreatic perineural invasion (PNI), the 1-year casefatality rate was 34.78%, which was not significantly different from that (28.57%) of patients with negative PNI (P=0.760). CONCLUSIONS: Our results suggested potential advantages of RND in the fields of surgery-associated risk and prognosis compared with the Whipple operation in the treatment of CHP. Due to the low sample size of this study, further well-designed research of large sample size is needed.

Silencing MRP1-4 genes by RNA interference enhances sensitivity of human hepatoma cells to chemotherapy.

AIM: Besides surgical treatment, systematic chemotherapy plays a crucial role in HCC treatment, especially for patients with advanced HCC. However, none of the single-drug-treatment strategies have shown significant survival benefit due to a high incidence rate of chemoresistance. This study was designed to observe the effect of small interfering of RNA (SiRNA) targeting multidrug resistance-related protein 1-4 (MRP1, MRP2, MRP3, and MRP4) in modulating drug resistance of HepG2/ADM and SMMC7721/ADM cells. METHODS: HepG2/Adriamycin (ADM) and SMMC7721/ADM cell lines were developed by exposing parental cells to stepwise increasing concentrations of ADM. MTT assay was used to determine drug sensitivity and half inhibitory concentration (IC50) of drugs was calculated. Flow cytometry was employed to analyze cell cycle distribution. MRP1-4 mRNA expression levels were measured by quantitative real-time PCR (QRT-PCR). Expression of proteins was analyzed by Western blot. The growth curve was draw and the cell apoptosis was also observed. Animal experiment was used to compare the cell growth. RESULTS: MTT assay showed that the values of IC50 and RI of HepG2/ADM and SMMC7721/ADM decreased after siRNA treatment in HepG2/ADM cells and SMMC7721/ADM cells. QRT-PCR analysis demonstrated the MRP1-4 mRNA expression decreased significantly in HepG2/ADM cells and SMMC7721/ADM cells after siRNA transfection. In addition, compared with parental cells, MRP1-4 protein expressions apparently decreased in SMMC7721/ADM and HepG2/ADM cells. Flow cytometry showed significantly elevated apoptosis rate following MRP1-4 siRNA transfection. Animal experiment suggested that silencing MRP1-4 gene in vivo inhibited tumor growth. CONCLUSION: Inhibition of MRP1-4 by small interfering RNA enhanced and selectively restored sensitivity of hepatoma cells to drugs. MRP1-4 siRNA might represent a new therapeutic option for HCC.

A retrospective cohort study of pancreatic neuroendocrine tumors at single institution over 15 years: New proposal for low- and high-grade groups, validation of a nomogram for prognosis, and novel follow-up strategy for liver metastases.

PURPOSE: Pancreatic neuroendocrine tumors (PNETs) exhibit various tumor behaviors and symptoms that are difficult for physicians to stage and predict prognosis. We assess prognostic factors combined with staging classifications to optimal the models and try to improve follow-up strategy to monitor liver metastases after surgery. METHODS: Patients with PNETs treated at Sun Yat-sen Memorial Hospital between 2000 and 2015 were recruited. Patients were regrouped on the basis of functional status and mitotic rates. Nomograms to predict the prognostic values of classifications (AJCC, ENETS, and WHO) were constructed; the accuracy of the nomograms were quantified by the C-index and calibration plots. RESULTS: We identified 78 PNETs patients with pathological reports. Correlations with OS in univariate analysis included nonfunctional status (P = 0.002), CgA>200 ng/ml (P < 0.001), Ki-67 (3-20%, P = 0.014; >20%, P < 0.001), and mitotic rate (3-20/10HPF, P = 0.011; >20/10HPF, P < 0.001). By multivariate analysis, nonfunctional status and mitotic rate maintained significance (P = 0.039; 3-20/10HPF, P = 0.015; >20/10HPF, P = 0.007). Evaluating the new proposed system, the difference in OS between low- and high-groups was statistically significant (P = 0.001). The C-index of the regrouped nomograms were higher than that of premise ones (AJCC cohort, 0.605 v 0.576, P < 0.01; ENETS cohort, 0.73 v 0.691, P < 0.01; WHO cohort, 0.678 v 0.603, P < 0.01). CONCLUSION: An prognostic model based on mitotic rates and functional status correlates strongly with survival. PNETs should return visits every 2 months for the first half years, and every 3 months as followed until 2 years after surgery.

Long non-coding RNA LOC389641 promotes progression of pancreatic ductal adenocarcinoma and increases cell invasion by regulating E-cadherin in a TNFRSF10A-related manner.

Long non-coding RNAs (lncRNAs) are important regulators in pathological processes, yet their potential roles in pancreatic ductal adenocarcinoma (PDAC) are poorly understood. Here, we found that a novel lncRNA, LOC389641, was upregulated in PDAC tissues and cell lines. The expression of LOC389641 was significantly correlated with staging, lymph node metastasis and overall survival. Knockdown of LOC389641 impaired cell proliferation and invasion and induced cell apoptosis in vitro, whereas overexpression of LOC389641 had the opposite effect. The growth promoting effect of LOC389641 was also demonstrated in vivo. Further, a significant negative correlation was observed between E-cadherin levels and LOC389641 levels in vivo. Knockdown of LOC389641 upregulated E-cadherin expression, but knockdown of E-cadherin had a limited influence on LOC389641. Importantly, after E-cadherin was inhibited, the enhancement of LOC389641 on cell invasion was hindered. Moreover, the expression of LOC389641 was closely associated with its genomic neighboring gene TNFRSF10A. Lastly, knockdown experiments showed that TNFRSF10A might be a connection between LOC389641and E-cadherin. We conclude that LOC389641 promotes PDAC progression and increases cell invasion by regulating E-cadherin with the possible involvement of TNFRSF10A.

Linc00675 is a novel marker of short survival and recurrence in patients with pancreatic ductal adenocarcinoma.

AIM: To detect linc00675 expression in pancreatic ductal adenocarcinoma (PDAC), to analyze the relationship between the expression level of linc00675 and the clinical pathological characteristics, to explore the biological functions of linc00675, and to determine whether linc00675 has independent prognostic value in PDAC. METHODS: We studied linc00675 expression among eight histologically confirmed PDAC tissue samples and four chronic pancreatitis tissue samples through microarray screening. RT-qPCR was conducted to further investigate linc00675 expression in PDAC cell lines as well as archived tissues from a large cohort of PDAC patients. The correlations between the level of lnc00675 and clinicopathological characteristics and survival in patients with pancreatic cancer were evaluated using Correlation analysis. Univariate and multivariate analyses were conducted to predict whether lnc00675 expression is an independent prognostic and recurrence factor in patients with pancreatic cancer. After downregulating the expression of linc00675 through siRNA, MTT assay, flow cytometry, transwell assay and Western blot were used to explore the biological function of linc00675 in proliferation, invasion, and cell cycle progression of pancreatic cancer cells. The relative molecular expression levels of epithelial-mesenchymal transition were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. RESULTS: The expression of Linc00675 in PDAC tissue samples was shown to be 672 times that in chronic pancreatitis tissue samples by microarray screening (P = 3.69 × 10(-5)). This finding was confirmed in tumor tissues from 90 patients with PDAC compared with adjacent normal tissue samples by quantitative RT-PCR. We found that linc00675 overexpression positively correlated with lymph node metastasis (P = 0.005), perineural invasion (P = 0.006), and poor survival (P < 0.001). Univariate and multivariate analyses showed that linc00675 expression served as an independent predictor of overall survival (P = 0.009). Additionally, receiver operating characteristic curve analysis showed that high linc00675 might serve as a predictor of tumor progression within 6 mo to a year after surgery. In vitro functional analysis demonstrated that knockdown of linc00675 attenuated pancreatic cancer cell proliferation and invasion as well as induced S phase arrest. Suppression of linc00675 in pancreatic cancer cells resulted can reverse the progress of epithelial-mesenchymal transition. CONCLUSION: Linc00675 may function as an oncogene during PDAC development, and its expression is an independent predictor of unfavorable prognosis in patients with PDAC.