Sirt1 S-nitrosylation induces acetylation of HMGB1 in LPS-activated RAW264.7 cells and endotoxemic mice

Excessive inflammation plays a detrimental role in endotoxemia. A recent study indicated that alarmins such as high mobility group box 1 (HMGB1) have drawn attention as therapeutic targets of sepsis. Post-translational modification (i.e., acetylation of lysine residues) of HMGB1 leads to the release of HMGB1 into the cellular space, operating as a warning signal that induces inflammation. Sirtuin 1 (SIRT1) has been shown to negatively regulate HMGB1 hyperacetylation and its extracellular release in sepsis. Therefore, we hypothesized that the S-nitrosylation (SNO) of SIRT1 may disrupt the ability of SIRT1 to negatively regulate the hyperacetylation of HMGB1. As long as the S-nitrosylation of SIRT1 occurs during septic conditions, it may worsen the situation. We found that the activity of SIRT1 decreased as the SNO-SIRT1 levels increased, resulting in HMGB1 release by LPS in RAW264.7 cells. Both the iNOS inhibitor (1400 W) and silencing iNOS significantly inhibited SNO-SIRT1, allowing increases in SIRT1 activity that decreased the HMGB1 release by LPS. SNAP, a NO donor, significantly increased both SNO-SIRT1 levels and the HMGB1 release that was accompanied by decreased sirt1 activity. However, sirtinol, a Sirt1 inhibitor, by itself decreased Sirt1 activity compared to that of the control, so that it did not affect already increased SNO-SIRT levels by SNAP. Most importantly, in lung tissues of LPS-endotoxic mice, significantly increased levels of SNO-SIRT were found, which was inhibited by 1400 W treatment. Plasma nitrite and HMGB1 levels were significantly higher than those in the sham controls, and the elevated levels were significantly lowered in the presence of 1400 W. We concluded that the S-nitrosylation of Sirt1 under endotoxic conditions may uninhibit the acetylation of HMGB1 and its extracellular release.

Development of immune and microbial environments is independently regulated in the mammary gland

Breastfeeding is important for mammals, providing immunological and microbiological advantages to neonates, together with the nutritional supply from the mother. However, the mechanisms of this functional diversity in the mammary gland remain poorly characterized. Here, we show that, similar to the gastrointestinal tract, the mammary gland develops immune and microbial environments consisting of immunoglobulin A (IgA) and the microflora, respectively, both of which are important for protecting neonates and the mother from infectious diseases. The IgA production and microflora development are coordinated in the gastrointestinal tract but seem to be independently regulated in the mammary gland. In particular, the chemokine (C-C motif) ligand 28 and poly-Ig receptor, crucial molecules for the IgA production in milk, were expressed normally in germ-free lactating mice but were almost undetectable in postweaning mothers, regardless of the microflora presence. Our findings offer insights into potentially improving the quality of breastfeeding, using both immunological and microbiological approaches.

JIB-04, A Small Molecule Histone Demethylase Inhibitor, Selectively Targets Colorectal Cancer Stem Cells by Inhibiting the Wnt/β-Catenin Signaling Pathway

Although several epigenetic modulating drugs are suggested to target cancer stem cells (CSCs), additional identification of anti-CSC drugs is still necessary. Here we showed that JIB-04, a pan-selective inhibitor of histone demethylase(s), was identified as a small molecule that selectively target colorectal CSCs. Our data showed that JIB-04 is capable of reducing self-renewal and stemness of colorectal CSCs in three different colorectal cancer cell lines. JIB-04 significantly attenuated CSC tumorsphere formation, growth/relapse, invasion, and migration in vitro. Furthermore, JIB-04-treated colorectal cancer cells showed reduced tumorigenic activity in vivo. RNA sequencing analysis revealed that JIB-04 affected various cancer-related signaling pathways, especially Wnt/β-catenin signaling, which is crucial for the proliferation and maintenance of colorectal cancer cells. qRT-PCR and TOP/FOP flash luciferase assays showed that JIB-04 down-regulated the expression of Wnt/β-catenin-regulated target genes associated with colorectal CSC function. Overall, the effects of JIB-04 were equal to or greater than those of salinomycin, a known anti-colorectal CSC drug, despite the lower concentration of JIB-04 compared with that of salinomycin. Our results strongly suggest that JIB-04 is a promising drug candidate for colorectal cancer therapy.

The Emerging Method of Suicide by Electronic Cigarette Liquid: a Case Report

Electronic cigarettes (ECs) are a device that aerosolize liquid nicotine by heating a solution of nicotine, glycerol and flavoring agents. The awareness and the usage of ECs has increased in many countries. Due to the online sales and the absence of EC regulations, the prevalence of EC usage is especially high in adolescents and young adults. Due to the large amount and the high nicotine concentration of EC liquid, the ingestion for suicide can lead to cardiac death. We had two patients, a 27-year-old male who ingested about 23 mg/kg of nicotine and a 17-year-old female who ingested about 30 mg/kg of nicotine. Both patients presented seizure-like movement and cardiac arrest. They had metabolic acidosis and transient cardiomyopathy. They were ultimately discharged with a cerebral performance category of 2 and 4, respectively. Increasing EC use may produce more cases of medical problems or suicide by nicotine intoxication.

Luteolin activates ERK1/2- and Ca2+-dependent HO-1 induction that reduces LPS-induced HMGB1, iNOS/NO, and COX-2 expression in RAW264.7 cells and mitigates acute lung injury of endotoxin mice

OBJECTIVE

Although luteolin has shown to have anti-inflammatory action, no report is available whether luteolin inhibits HMGB1 and protects acute lung injury (ALI) in endotoxin rodents. We hypothesized that HO-1 induction by luteolin might play a crucial role for inhibition of pro-inflammatory mediators including HMGB1 through MAPK signaling in LPS-induced RAW264.7 cells, and it ameliorates ALI of endotoxin mice.

METHODS

The effects of luteolin on the production of pro-inflammatory mediators in LPS-activated RAW264.7 cells and LPS-injected mice were evaluated. The mechanisms were investigated using various signal inhibitors.

RESULTS

Luteolin significantly increased HO-1 expression through ERK1/2 signaling in a time- and concentration-dependent manner. Indeed, luteolin inhibited pro-inflammatory mediators (HMGB1, iNOS/NO, COX-2, and NF-κB activity) in LPS-activated RAW264.7 cells. In addition, PD98059, an ERK1/2 inhibitor, treatment failed to inhibit production of these pro-inflammatory mediators by luteolin. Interestingly, luteolin augmented HO-1 induction through Ca²⁺ influx in RAW264.7 cells. Administration of luteolin significantly inhibited plasma HMGB1 level, and iNOS expression in the lung that resulted in a significant reduction of ALI in endotoxin mice that was reversed by a HO-1 inhibitor, ZnPPIX.

CONCLUSION

Therefore, we conclude that luteolin has a great potential for treatment of ALI and related diseases, where HMGB1 is a therapeutic target.

Loss of BRCA1 Spontaneously Induces the Tumorigenesis in Lacrimal Gland

Environmental and genetic factors exert important influences on lifespan and neoplastic transformation. We have previously shown that spontaneous tumors form frequently in mice homozygous for a full-length Brca1 deletion. In general, mutations of BRCA1 are closely associated with induction of breast and ovarian cancers but are also known to contribute to the incidence of other cancers at a low frequency. Female Brca1-mutant mice (Brca1^co/coMMTV-cre) were generated by crossing Brca1 conditional knockout mice and MMTV-cre mice, and the occurrence of lacrimal gland abnormalities and tumors was followed until mice reached 18 months of age. Lacrimal gland tumors, which occur at a very low frequency in the human population (1 per 1,000,000 per year), were detected in 7 cases of Brca1^co/coMMTV-cre mice (2.75%) older than 9 months of age. None of seven mice exhibited any abnormality in the mammary gland including neoplasia, suggesting lacrimal gland tumor is spontaneously and independently formed. These tumors, which were detected in seven mutant mice that displayed exophthalmoses, were malignant, originated from epithelial cells, and were identified as acinic cell carcinoma by pathological analysis. Further analysis revealed that tumorigenesis was accompanied by the accumulation of cyclin D1 and decreased expression of the cellular oncogenes, c-Myc, c-Jun, and c-Raf. Tumors also exhibited rearrangement of cytoskeletal proteins, including β-catenin, keratin 5, and vimentin, depending on tumor progression. These results suggest that BRCA1 is involved in genetic stability of the lacrimal gland, providing new insight into genomic instability in organism maintenance and tumorigenesis of the lacrimal gland.

Laparoscopic and Robotic Surgeries for Patients With Colorectal Cancer Who Have Had a Previous Abdominal Surgery

PURPOSE

The impact of previous abdominal surgery (PAS) on surgical outcomes from laparoscopic and robot surgeries is inconclusive. This study aimed to investigate the impact of PAS on perioperative outcomes from laparoscopic and robotic colorectal surgeries.

METHODS

From March 2007 to February 2014, a total of 612 and 238 patients underwent laparoscopic and robotic surgeries, respectively. Patients were divided into 3 groups: those who did not have a PAS (NPAS), those who had a major PAS, and those who had a minor PAS. We further divided the patients so that our final groups for analysis were: patients with NPAS (n = 478), major PAS (n = 19), and minor PAS (n = 115) in the laparoscopy group, and patients with NPAS (n = 202) and minor PAS (n = 36) in the robotic surgery group.

RESULTS

In the laparoscopy group, no differences in the conversion rates between the 3 groups were noted (NPAS = 1.0% vs. major PAS = 0% vs. minor PAS = 1.7%, P = 0.701). In the robotic surgery group, the conversion rate did not differ between the NPAS group and the minor PAS group (1.0% vs. 2.8%, P = 0.390). Among the groups, neither the operation time, blood loss, days to soft diet, length of hospital stay, nor complication rate were affected by PAS.

CONCLUSION

PAS did not jeopardize the perioperative outcomes for either laparoscopic or robotic colorectal surgeries. Therefore, PAS should not be regarded as an absolute contraindication for minimally invasive colorectal surgeries.

The efficacy of infliximab combined with surgical treatment of fistulizing perianal Crohn's disease: Comparative analysis according to fistula subtypes

BACKGROUND/OBJECTIVE

Infliximab is regarded as an effective therapeutic to treat Crohn's disease. This study aimed to assess the efficacy of infliximab combined with surgery and to analyze clinical manifestations according to fistula subtypes in patients with fistulizing perianal Crohn's disease.

METHODS

From April 2013 to December 2015, 47 patients with perianal Crohn's disease in two hospitals of South Korea (Goo Hospital, Gangnam Severance Hospital) were evaluated retrospectively. Patients were categorized into two groups as simple fistula (n = 20) and complex fistula group (n = 27). All patients received 5 mg/kg of infliximab intravenously at 0, 2, and 6 weeks after surgical treatments. Then every eight weeks, the responders continued to receive 5 mg/kg infliximab for maintenance therapy.

RESULTS

Complete response of induction therapy was 72.3%, and partial response was 27.7%. After maintenance therapy, complete response was 97.9% and partial response was 2.1%. There was no patient without a response to infliximab in this study. The median time to the first fistula closure was 6.00 ± 8.00 weeks. Infliximab was used on average 2.13 ± 0.71 times until the first fistula closure. The rate of recurrence was 8.5% and adverse events were 4.2%. In comparison with clinical manifestations between simple and complex fistula groups, there was no significant difference except for the coexistence of perianal abscess.

CONCLUSIONS

Combined surgical and infliximab therapy was efficacious to treat fistulizing perianal Crohn's disease with rapid treatment response and favorable clinical outcomes. It is expected that this top-down strategy with combining surgeries can overcome previous limitations in treating perianal Crohn's disease.

Retinoblastoma protein (Rb) links hypoxia to altered mechanical properties in cancer cells as measured by an optical tweezer

Hypoxia modulates actin organization via multiple pathways. Analyzing the effect of hypoxia on the biophysical properties of cancer cells is beneficial for studying modulatory signalling pathways by quantifying cytoskeleton rearrangements. We have characterized the biophysical properties of human LNCaP prostate cancer cells that occur in response to loss of the retinoblastoma protein (Rb) under hypoxic stress using an oscillating optical tweezer. Hypoxia and Rb-loss increased cell stiffness in a fashion that was dependent on activation of the extracellular signal-regulated kinase (ERK) and the protein kinase B (AKT)- mammalian target of rapamycin (MTOR) pathways. Pharmacological inhibition of MEK1/2, AKT or MTOR impeded hypoxia-inducible changes in the actin cytoskeleton and inhibited cell migration in Rb-deficient cells conditioned with hypoxia. These results suggest that loss of Rb in transformed hypoxic cancer cells affects MEK1/2-ERK/AKT-MTOR signalling and promotes motility. Thus, the mechanical characterization of cancer cells using an optical tweezer provides an additional technique for cancer diagnosis/prognosis and evaluating therapeutic performance.

Randomized, noninferiority study between video versus hand ultrasound with wet foam dressing materials to simulate B-lines in lung ultrasound: A CONSORT-compliant article

BACKGROUND

This study evaluated the efficacy of a teaching method using simulated B-lines of hand ultrasound with a wet foam dressing material.

METHODS

This prospective, randomized, noninferiority study was conducted on emergency medical technician students without any relevant training in ultrasound. Following a lecture including simulated (SG) or real video clips (RG) of B-lines, a posttest was conducted and a retention test was performed after 2 months. The test consisted of questions about B-lines in 40 randomly mixed video clips (20 simulated and 20 real videos) with 4 answer scores (R-1 [the correct answer score for the real video clips] vs S-1 [the correct answer score for the simulated video clips] in the posttest, R-2 [the correct answer score for the real video clips] vs S-2 [the correct answer score for the simulated video clips] in the retention test).

RESULTS

A total of 77 and 73 volunteers participated in the posttest (RG, 38; SG, 39) and retention test (RG, 36; SG, 37), respectively. There was no significant (P > .05) difference in scores of R-1, S-1, R-2, or S-2 between RG and SG. The mean score differences between RG and SG were -0.6 (95% confidence interval [CI]: -1.49 to 0.11) in R-1, -0.1 (95% CI: -1.04 to 0.86) in S-1, 0 (95% CI: -1.57 to 1.50) in R-2, and -0.2 (95% CI: -1.52 to 0.25) in S-2. The mean differences and 95% CIs for all parameters fell within the noninferiority margin of 2 points (10%).

CONCLUSION

Simulated B-lines of hand ultrasound with a wet foam dressing material were not inferior to real B-lines. They were effective for teaching and simulations.

TRIAL REGISTRATION

The study was registered with the Clinical Trial Registry of Korea: https://cris.nih.go.kr/cris/index.jsp (KCT0002144).

Scutellaria baicalensis Georgi induces caspase-dependent apoptosis via mitogen activated protein kinase activation and the generation of reactive oxygen species signaling pathways in MCF-7 breast cancer cells

Scutellaria baicalensis Georgi extract (SBGE) is used in traditional herbal medicine and has also been used clinically to ameliorate the symptoms of various inflammatory diseases and cancer. In women, breast cancer is one of the most common diseases and numerous women succumb to it. The present study was undertaken to investigate the mechanism responsible for the SBGE‑induced apoptosis of MCF‑7 human breast cancer cells. SBGE was administered to cells at concentrations between 100 and 500 mg/ml, and cell viabilities were identified using an MTT assay. B‑cell lymphoma 2 (Bcl-2) and Bcl-2 X‑associated protein (Bax) family members were identified by western blotting, and the mRNA expression levels of the pro‑apoptosis genes Fas, Fas ligand (FasL) and tumor necrosis factor (TNF)‑α were assessed by reverse transcription‑polymerase chain reaction. It was identified that SBGE treatment for 24 h inhibited MCF‑7 proliferation and increased the sub‑G1 phase ratio. SBGE suppressed mitochondrial membrane potentials and SBGE‑induced apoptotic cell death was identified to be associated with downregulation of Bcl‑2, but upregulation of Bax. SBGE‑activated caspases 3 and 9, and increased reactive oxygen species generation. However, SBGE had no effect on the expression levels of Fas, FasL or TNF‑α. Furthermore, mitogen‑activated protein kinase and C‑Jun N‑terminal kinase inhibitors inhibited SBGE‑induced cell death. These results suggested that SBGE be considered as an agent for the treatment of breast cancer.

Useful Computed Tomography Score for Estimation of Early Neurologic Outcome in Post-Cardiac Arrest Patients With Therapeutic Hypothermia

BACKGROUND

The Alberta Stroke Program Early CT Score (ASPECTS) is used to assess early ischemic stroke damage. This study compared bilateral ASPECTS (ASPECTS-b) with the gray:white matter ratio (GWR) and quantitative regional abnormality (QRA) to evaluate the prognostic utility of early computed tomography (CT) findings in post-cardiac arrest patients.Methods and Results:Out-of-hospital cardiac arrest patients with return of spontaneous circulation (ROSC) who underwent brain CT (<6 h after onset) and therapeutic hypothermia were recruited from a university hospital over a 2-year period. General demographics, ROSC characteristics, ASPECTS-b (total score=20 points), GWR, and QRA were assessed. Multivariate logistic regression analysis was used to predict neurologic outcome using cerebral performance category (CPC) at 1 month. The study population was divided into good (n=20; CPC 1-2) and poor (n=47; CPC 3-5) outcome groups. The good (vs. poor) outcome group was younger (mean [±SD] age 46.7±11.8 vs. 60.3±17.2 years; P=0.002) and had more initial shockable rhythms (40.0% vs. 8.5%; P=0.002). In addition, the good outcome group had a higher mean ASPECTS-b score (15.3±2.7 vs. 9.0±4.9; P<0.001), despite no differences in QRA and mean GWR. Age and ASPECTS-b were independent predictors of outcome after adjusting for potential confounders.

CONCLUSIONS

These findings suggest that an initial CT score (ASPECTS-b) could help estimate early neurologic outcomes in post-cardiac arrest patients treated with therapeutic hypothermia.

Coincidence of Persistent Müllerian duct syndrome and testicular tumors in dogs

BACKGROUND

Persistent Müllerian duct syndrome (PMDS), a rare form of male pseudohermaphroditism in dogs, is an abnormal sexual phenotype in males that is characterized by the existence of a hypoplastic oviduct, uterus, and cranial part of the vagina. Dogs suffering from PMDS are often accompanied by cryptorchidism. To date, it has been mainly found in the Miniature Schnauzer breed.

CASE PRESENTATION

In this report, two cases of PMDS with a malignant testicular tumor originating from cryptorchidism in breeds other than the Miniature Schnauzer breed are described. The patients were a seven-year-old male Maltese dog and a 17-year-old male mixed-breed dog weighing 3.8 kg. They also exhibited an enlarged prostate with or without abscess and an elevated serum estradiol level and were surgically treated to remove the testicular tumor and Müllerian duct derivatives.

CONCLUSIONS

It is recommended that PMDS should be differentially diagnosed by ultrasonography and that orchiectomy be performed at an early age in patients suspected to have cryptorchidism to prevent the ectopic testes from becoming tumorous.

Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy for appendiceal and colorectal cancer with peritoneal carcinomatosis: Clinical outcomes at 2 tertiary referral centers in Korea

Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) is regarded as effective surgical treatments in patients with peritoneal metastasis. This study aimed to evaluate the clinical outcomes of CRS and HIPEC in patients with appendiceal or colorectal cancer with peritoneal carcinomatosis.A total of 66 patients who underwent CRS with HIPEC for appendiceal or colorectal cancer with peritoneal metastasis at 2 tertiary referral centers in Korea were evaluated between July 2014 and March 2016. The perioperative outcomes and postoperative complications were evaluated prospectively.The mean peritoneal cancer index (PCI) was 15.3 ± 10.5. The distributions thereof were as follows: PCI < 10, 33.3%; PCI 10-19, 36.4%; and PCI≥20, 30.3%. Regarding completeness of cytoreduction (CC), 59.1% of patients achieved CC-0, with 18.2% showing CC-1 and 22.7% showing CC-2. The mean operation time was 9.4 hours, and the mean hospital stay was 20.2 days. The overall rate of short-term complications was 74.2%; the rate of long-term complications was 10.6%. In the short-term period, most complications were grades I-II complications (62.1%), compared to grades III-V (12.1%). All long-term complications, occurring in 10.6% of patients, were grades III-V.In this study, CRS with HIPEC was deemed feasible and safe for treating stage IV appendiceal or colorectal cancer with peritoneal carcinomatosis in Koreans.

CHK2 is involved in the p53-independent radiosensitizing effects of valproic acid

Radiotherapy is an effective treatment for the majority of types of localized solid cancer. However, the risk of side effects to the surrounding normal tissues limits radiotherapeutic approaches. Whilst the mechanism of action of valproic acid, an inhibitor of histone deacetylase, remains unknown, the inhibitor is a potential antineoplastic radiosensitizer. The present study demonstrated the in vitro radiosensitizing effects of valproic acid on the human breast cancer MCF7 cell line, and revealed that valproic acid increased the level of DNA breakage, apoptosis and senescence. In addition, western blot analyses revealed that valproic acid induced tumor suppressor protein (p)53 and p21 expression, and activated checkpoint kinase 2 (CHK2) in MCF7 cells and primary mouse embryonic fibroblasts. Notably, treatment with valproic acid also induced increases in the level of p21 protein levels and CHK2 activity in p53-null colon cancer HCT116 cells. Furthermore, the present study demonstrated that valproic acid-induced radiosensitization was largely dependent on the activity of CHK2. The results of the present study reveal that valproic acid may exhibit clinical utility with respect to increasing the anticancer efficacy of radiotherapy by affecting the level of p53.

Glatiramer acetate attenuates the activation of CD4+ T cells by modulating STAT1 and -3 signaling in glia

Interactions between immune effector cells of the central nervous system appear to directly or indirectly influence the progress/regression of multiple sclerosis (MS). Here, we report that glial STAT1 and -3 are distinctively phosphorylated following the interaction of activated lymphocytes and glia, and this effect is significantly inhibited by glatiramer acetate (GA), a disease-modifying drug for MS. GA also reduces the activations of STAT1 and -3 by MS-associated stimuli such as IFNγ or LPS in primary glia, but not neurons. Experiments in IFNγ- and IFNγ receptor-deficient mice revealed that GA-induced inhibitions of STAT signaling are independent of IFNγ and its receptor. Interestingly, GA induces the expression levels of suppressor of cytokine signaling-1 and -3, representative negative regulators of STAT signaling in glia. We further found that GA attenuates the LPS-triggered enhancement of IL-2, a highly produced cytokine in patients with active MS, in CD4+ T cells co-cultured with glia, but not in CD4+ T cells alone. Collectively, these results provide that activation of glial STATs is an essential event in the interaction between glia and T cells, which is a possible underlying mechanism of GA action in MS. These findings provide an insight for the development of targeted therapies against MS.

Ethyl pyruvate inhibits the acetylation and release of HMGB1 via effects on SIRT1/STAT signaling in LPS-activated RAW264.7 cells and peritoneal macrophages

High mobility group box 1 (HMGB1), a cytokine present in the late phase of sepsis, may be a potential target for the treatment of sepsis. For HMGB1 to be actively secreted from macrophages during infections, it must be post-translationally modified. Although ethyl pyruvate (EP), a simple aliphatic ester derived from pyruvic acid, has been shown to inhibit the release of HMGB1 in lipopolysaccharide (LPS)-treated RAW 264.7 cells, the underlying mechanism(s) are not yet clear. We investigated the hypothesis that the upregulation of SIRT1 by EP might promote the deacetylation of HMGB1, which reduces HMGB1 release in LPS-activated macrophages. Our results show that EP induced the expression of the SIRT1 protein in RAW264.7 cells and that it significantly inhibited the LPS-induced acetylation of HMGB1. Transfection with a SIRT1-overexpressing vector resulted in a significant decrease in the acetylation of HMGB1 in LPS-activated RAW264.7 cells relative to control cells. The genetic ablation or the pharmacological inhibition of SIRT1 by sirtinol increased LPS-induced HMGB1 acetylation. Moreover, EP inhibited the acetylation of HMGB1 in peritoneal macrophages treated with LPS. Interestingly, EP significantly reduced the LPS-induced phosphorylation of STAT1, which was significantly reversed by siSIRT1 transfection in RAW264.7 cells, indicating that SIRT1 negatively regulates the phosphorylation of STAT1. Overall, the results show that EP promotes the deacetylation of HMGB1 via the inhibition of STAT1 phosphorylation through the upregulation of SIRT1, which reduces HMGB1 release in LPS-activated RAW264.7 cells. In conclusion, EP might be useful in the treatment of diseases that target HMGB1, such as sepsis.

nc886, a non-coding RNA and suppressor of PKR, exerts an oncogenic function in thyroid cancer

nc886 is a recently identified cellular non-coding RNA and its depletion leads to acute cell death via PKR (Protein Kinase RNA-activated) activation. nc886 expression is increased in some malignancies, but silenced in others. However, the precise role of nc886/PKR is controversial: is it a tumor suppressor or an oncogene? In this study, we have clarified the role of nc886 in thyroid cancer by sequentially generating PKR knockout (KO) and PKR/nc886 double KO cell lines from Nthy-ori 3-1, a partially transformed thyroid cell line. Compared to the wildtype, PKR KO alone does not exhibit any significant phenotypic changes. However, nc886 KO cells are less proliferative, migratory, and invasive than their parental PKR KO cells. Importantly, the requirement of nc886 in tumor phenotypes is totally independent of PKR. In our microarray data, nc886 KO suppresses some genes whose elevated expression is associated with poor survival confirmed by data from total of 505 thyroid cancer patients in the Caner Genome Atlas project. Also, the nc886 expression level tends to be elevated and in more aggressively metastatic tumor specimens from thyroid cancer patients. In summary, we have discovered nc886's tumor-promoting role in thyroid cancer which has been concealed by the PKR-mediated acute cell death.