A positive feedback regulation between long noncoding RNA SNHG1 and YAP1 modulates growth and metastasis in laryngeal squamous cell carcinoma.

Laryngeal squamous cell carcinoma (LSCC) is the second highest incidence among the head and neck malignancies. Long noncoding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) functions as an oncogene in various human cancers. However, the biological functions and molecular mechanisms of SNHG1 in LSCC have not been reported. In this study, we found that lncRNA SNHG1 is significantly upregulated in LSCC and associated with prognosis of LSCC patients. Knockdown of SNHG1 inhibited cell proliferation, migration and invasion and induced cell apoptosis. In addition, knockdown of SNHG1 inhibits LSCC growth and metastasis in vivo. Mechanistically, SNHG1 promotes YAP1 expression and Hippo signaling activity by competitively sponging miR-375. Moreover, YAP1 could occupy the SNHG1 promoter to enhance its transcription, suggesting that there exists a positive feedback regulation between YAP1 and SNHG1. Collectively, our study first elucidates the mechanism of SNHG1-mediated malignant phenotypes through evoking the miR-375/YAP1/Hippo signalling axis, which provides a novel target for LSCC treatment.

LncRNA THOR attenuates cisplatin sensitivity of nasopharyngeal carcinoma cells via enhancing cells stemness.

The roles and mechanisms of long non-coding RNAs (lncRNA) in nasopharyngeal carcinoma (NPC) cells stemness and chemotherapeutic sensitivity are unclear. Here, Quantitative real-time PCR (qRT-PCR) was performed to detect the lncRNA THOR expression in NPC and normal adjacent tissues, adherent NPC cells and non-adherent NPC spheres, and we found that THOR was significantly increased in NPC tissues and non-adherent NPC spheres. Further in vitro and in vivo experiments were carried out and identified that knockdown of THOR attenuated NPC cells stemness, characterized as the decrease of spheres formation ability, cell proliferation, migration, invasion, stemness markers expression and tumor initiation, and enhanced cisplatin sensitivity of NPC cells. Mechanistically, RNA immunoprecipitation (RIP), immunofluorescence and luciferase reporter analysis indicated that THOR could enhance YAP transcriptional activity via directly binding to YAP and suppressing its translocation from nuclear to cytoplasm. Notably, overexpression of YAP rescued the inhibition of THOR knockdown on NPC cells and spheres stemness and promotion on cisplatin sensitivity. Thus, our results demonstrate that lncRNA THOR could attenuate cisplatin sensitivity of NPC cells by enhancing cells stemness through promoting YAP transcriptional activity.

NU7441 Enhances the Radiosensitivity of Liver Cancer Cells.

OBJECTIVE: Radiation therapy, one of the major treatments for liver cancer, causes DNA damage and cell death. Since the liver cancer cells have a strong capacity to repair irradiative injury, new medicines to enhance this treatment are urgently required. In this study, we investigated the effect of NU7441, a synthetic small-molecule compound, as a specific inhibitor of DNA-dependent protein kinase (DNA-PK) in radiosensitization of hepatocellular carcinoma HepG2 cells. METHODS: Cell Counting Kit-8 (CCK-8) was first used to evaluate the proliferation of HepG2 cells under NU7441 treatment. SDS-PAGE and Western blot were then performed to study the protein expression leading to the DNA damage repair. Further, neutral single cell gel electrophoresis and immunofluorescence assay were carried out to assess DNA repair. Finally, flow cytometry was implemented to examine the changes in cell cycle. RESULTS: NU7441 reduced the CCK-8 counts in the HepG2 culture, further enhanced 60Cox03B3; radiation injury to HepG2 cells, which was manifested by decreasing the DNA-PKcs (S2056) protein expression, increasing x03B3;H2AX foci number, prolonging the tail moment of the comet cells, and inducing cell cycle arrest at G2/M phase. CONCLUSION: NU7441 inhibited the growth of liver cancer cells, enhanced the radiosensitization of these cancer cells by interfering with the DNA repair and cell cycle checkpoint. These data implicate NU7441 as a potential radiotherapy sensitizer for the treatment of liver cancer.

[Clinical observation of relapsing polychondritis: a report of 23 patients].

OBJECTIVE: To explore the clinical characteristics of relapsing polychondritis (RP) for its early diagnosis and treatment. METHODS: A retrospective analysis was performed for the clinical data and prognoses for 23 RP patients from April 1996 to October 2011 at Departments of Respiratory Medicine, Rheumatism and Otorhinolaryngology, First Affiliated Hospital, Zhengzhou University. RESULTS: Lesion locations included auricle (n = 19), joints (n = 17), nose (n = 14), respiratory tract (n = 10), eyes (n = 6), inner ear (n = 4), costal cartilage (n = 3) and kidney (n = 1). Laboratory examinations revealed elevated erythrocyte sedimentation rate (ESR) (n = 18), elevated C-reactive protein (CRP) (n = 16) and positive rheumatoid factor (n = 2). Laryngeal mucosa was edematous and the vocal cords were paralyzed in the cases with airway involvement under laryngofiberscopy. Tracheal mucosa was highly edematous and tracheal lumen narrowed in the cases examined under bronchofibroscope. Laryngeal mucosa was swollen, glottic chink narrowed, laryngeal cartilage partially absorbed and deformed in the cases examined with neck computed tomography (CT). Tracheal mucosa was thickened, tracheal lumen narrowed and tracheal cartilage was deformed and calcified in the cases on chest CT. Pathological examination on tracheal cartilage showed that cartilage tissue was degenerative and fibrotic. And the proliferation of granulation tissue and the infiltration of inflammatory cells were present around cartilage tissue. Twenty-three RP patients received the therapies of antibiotics, glucocorticosteroid, immunosuppressive agent, tracheotomy or tracheal stent implantation. Two cases died of asphyxia. One case died of myocardial infarct. The symptoms of other 20 cases improved in different degrees. CONCLUSION: The clinical manifestations are diverse in RP patients. The prognoses of patients with airway involvement are worse and may be improved by an early diagnosis and correct treatment.

[Effects of sodium butyrate on growth, apoptosis and telomerase activity in Hep-2 cells].

OBJECTIVE: To study the effects of sodium butyrate (SB) on growth, apoptosis and telomerase activity in Hep-2 cells. METHODS: Growth inhibition effect of SB on Hep-2 cells was assessed by methyl thiazolyl tetrazolium (MTT) assay. Morphological alterations were observed by electronic microscope. Cell apoptosis was confirmed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling (TUNEL) method, DNA fragmentation and flow cytometry (FCM). Cell cycle was analyzed by FCM. Telomerase activity was examined by telomeric repeat amplification protocol (TRAP)-silver staining. The expression status of telomerase subunits was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: A time-and dose-dependent inhibition was detected in cells treated with SB. Typical morphological changes of apoptotic cells were observed under electronic microscopy. The characteristic DNA fragmentation of apoptotic cells was detected by agarose gel electrophoresis. Apoptosis and the changes of cell cycle were confirmed by TUNEL method and FCM. The apoptosis indexes of the cells before treatment and at 72 h after SB (2.5 mmol/L) treatment were 2.27 +/- 1.18 and 33.50 +/- 2.75 respectively, the apoptosis rates were 2. 86% and 31. 28% respectively, the proportion of the cells at G0/G1 stage were 50.38% and 70.88% respectively, the proportion of the cells at S stage were 27.40% and 8.20% respectively, and the proliferation indexes of the cells were 49.62% and 29.12% respectively. Telomerase activity and expression level of human telomerase reverse transcriptase (hTERT), the key subunit of telomerase, decreased after SB treatment. No significant changes were observed in the expression of human telomerase RNA (hTR) and human telomerase associated protein (hTP1), the other two subunit of telomerase. CONCLUSION: SB could inhibit growth of Hep-2 cells and induce apoptosis in the cells, and inhibit telomerase activity by decrease expression level of hTERT.