METTL3 modulates m6A modification of CDC25B and promotes head and neck squamous cell carcinoma malignant progression.

BACKGROUND: N6-methyladenosine (m6A) RNA methylation and its methyltransferase METTL3 have been widely reported to be involved in different cancers by regulating RNA metabolism and function. Here, we aimed to explore the biological function and clinical significance of m6A modification and METTL3 in head and neck squamous cell carcinoma (HNSCC). METHODS: The prognostic value of METTL3 expression was evaluated using tissue microarray and immunohistochemical staining analyses in a human HNSCC cohort. The biological role and mechanism of METTL3 in HNSCC tumour growth, metastasis and angiogenesis were determined in vitro and in vivo. RESULTS: M6A levels and METTL3 expressions in HNSCC tissues were significantly increased compared with paired adjacent tissues. Meanwhile, METTL3 was an independent risk factor for the prognosis of HNSCC patients. Moreover, METTL3 overexpression promoted HNSCC cell proliferation, migration, invasion, and angiogenesis, while knockdown of METTL3 had an opposite effect in vivo and in vitro. Mechanistically, METTL3 enhanced the m6A modification of CDC25B mRNA, which maintained its stability and upregulated its expression, thereby activating G2/M phase of cell cycle and leading to HNSCC malignant progression. CONCLUSIONS: METTL3 may be a potential prognostic biomarker and therapeutic target for HNSCC.

Role of epithelial-mesenchymal transition markers E-cadherin, N-cadherin, ß-catenin and ZEB2 in laryngeal squamous cell carcinoma.

Epithelial-mesenchymal transition (EMT) allows neoplastic cells to gain the invasive phenotype and become migratory, which is required for cancer progression and metastasis. In the present study, the expression of EMT-associated biomarkers and their association with clinicopathological parameters in laryngeal squamous cell carcinoma (LSCC) was investigated. E-cadherin, N-cadherin, ß-catenin and zinc finger E-box binding homeobox 2 (ZEB2) protein expression was evaluated with immunohistochemistry in a cohort of 76 patients with operable LSCC. The association between these transition markers, clinicopathological parameters and their prognostic impact in LSCC was analyzed. Immunohistochemical analysis revealed that EMT-associated proteins were differentially expressed between LSCC and adjacent non-neoplastic laryngeal tissue. Negative E-cadherin expression and positive N-cadherin, ß-catenin and ZEB2 expression were associated with a later tumor (T) stage, decreasing tumor differentiation and a reduced overall survival (OS) time (OS: E-cadherin, P=0.016; N-cadherin, P=0.003; ß-catenin, P=0.002; ZEB2, P=0.0003). E-cadherin/ß-catenin co-expression was significantly associated with the majority of clinicopathological parameters assessed, including lymph node metastases, T stage and tumor cell differentiation (P=0.004, P=0.005, and P<0.001, respectively). Multivariate analysis indicated that T stage and the positive expression of ß-catenin and ZEB2 were independent risk factors for OS in LSCC (P=0.014, P=0.025 and P=0.003, respectively). It was concluded that EMT mediates tumor progression, and reduces OS time in patients with LSCC. E-cadherin/ß-catenin co-expression may be associated with clinicopathological parameters. T stage, and the positive co-expression of ß-catenin and ZEB2 may be independent predictors of prognosis in LSCC.

Myosin light chain kinase regulates hearing in mice by influencing the F-actin cytoskeleton of outer hair cells and cochleae.

Myosin light chain kinase (MLCK) phosphorylates myosin regulatory light chains to facilitate its interaction with actin filaments and produce contractile activity. The outer hair cells (OHCs) in the ear contain large amounts of actin and a variety myosins. The stereociliary and somatic motility of OHCs are closely related to hearing. It appears likely that MLCK may play an important role in acoustic trans-duction. In this study, we analyzed, both in vivo and in vitro, the OHCs of mice bearing a specific deletion of the MLCK gene and the OHCs of control mice. The phenotype was assessed by auditory function [acoustic brainstem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs)], inner ear morphology and histology. MLCK-deficient mice aged 6-7 months showed impaired hearing, a 5- to 10-dB sound pressure level (SPL) increase in the ABR thresholds, when responding to clicks and tones of different frequencies (8 and 16 kHz) (P<0.05). The DPOAE amplitudes of 3-month-old MLCK-deficient mice decreased significantly (>10 dB SPL) at low frequencies (4, 5 and 6 kHz). The OHCs in the MLCK-deficient mice increased with abnormal stereocilia. The staining of F-actin and the phosphorylation of the regulatory light chain in MLCK-deficient OHCs was weak. Our results indicate that MLCK may regulate the structure and the motility of stereocilia through F-actin polymerization.

[Clinical application of minimally invasive core decompression combined with impaction bone grafting to the treatment of femoral head necrosis].

OBJECTIVE: To explore a simple,effective threrapeutic method for the treatment of ischemia necrosis of femoral head. METHODS: From March 2003 to April 2008, 61 hips of 55 patients, including 37 males and 18 females, aged from 12 to 55 years old (averaged 39.8), with ischemia necrosis of femoral head were treated by three methods combination of partial synovectomy, minimally invasive core decompression and impaction bone grafting. The course of diseace was from 8 months to 16 years. The therapeutic effects were evaluated according to the preoperative and postoperative X-ray and Harris scoring for hip funtion. RESULTS: These 55 patients (61 hips) were followed up for from 6 mouths to 5 years (means 2.2 years). X-ray results showed that collapse or aggrevation occurenced in 39 hips,the aggravation of collapse no more than 2 mm in 11 hips,the collapse from 2 to 4 mm in 9 hips, the collapse surpassed 4 mm in 2 hips. Harris scores increased obviously from preoperative (59.74 +/- 11.56) points to postoperative (89.75 +/- 9.58) points (t = 2.3461, P < 0.05). The results were excellent in 31 hips, good in 22 hips, fair in 6 hips and poor in 2 hips. CONCLUSION: Minimally invasive core decompression combined with impaction bone grafting can reduce the stress load of femoral head, stabilized the environment of femoral head,promote osteonecrotic bone rapairing and prevent effectively the femoral head form collapsing. This method can be applied to femoral head necrosis at Ficat II, III stage, especially for young and middle-age patients.