The lncRNA LINC00460 plays crucial roles in several epithelial cancers, although its mechanisms of action differ greatly in different cellular contexts. In this study, we aimed to determine the potential clinical applications of LINC00460 and elucidate the mechanisms by which LINC00460 affects the development and progression of head and neck squamous cell carcinoma (HNSCC). The biological functions of LINC00460 were assessed in several epithelial cancer cell lines. The subcellular localization of LINC00460 was evaluated by cell nuclear/cytoplasmic fractionation and fluorescence in situ hybridization. RNA pull-down assays, LS-MS/MS analysis, and RNA and chromatin immunoprecipitation assays were performed to identify the molecular mechanism by which LINC00460 promotes HNSCC progression. The clinical pathological features of LINC00460 and PRDX1 were evaluated in HNSCC tissues and paired adjacent normal tissues. LINC00460 enhanced HNSCC cell proliferation and metastasis in vitro and in vivo and induced epithelial–mesenchymal transition (EMT). LINC00460 primarily localized within the cytoplasm of HNSCC cells, physically interacted with PRDX1 and facilitated PRDX1 entry into the nucleus. PRDX1 promoted the transcription of LINC00460, forming a positive feedback loop. In addition, PRDX1 also promoted the transcription of EMT-related genes (such as ZEB1, ZEB2 and VIM) through enrichment on gene promoters in the nucleus. LINC00460 effectively induced HNSCC cell EMT in a PRDX1-dependent manner, and PRDX1 mainly mediated the EMT-promoting effect of LINC00460. High levels of LINC00460 and PRDX1 expression were positively associated with lymph metastasis, pathological differentiation and tumor size in HNSCC patients. LINC00460 promoted EMT in HNSCC cells by facilitating PRDX1 entry into the nucleus. LINC00460 and PRDX1 are promising candidate prognostic predictors and potential targets for cancer therapy for HNSCC.

Background: Bone loss and pathological fractures are common skeletal complications associated with androgen deprivation therapy and bone metastases in prostate cancer patients. We have previously demonstrated that prostate cancer cells secrete receptor activator of NF-kB ligand (RANKL), a protein essential for osteoclast differentiation and activation. However, the mechanism(s) by which RANKL is produced remains to be determined. The objective of this study is to gain insight into the molecular mechanisms controlling RANKL expression in metastatic prostate cancer cells.Results: We show here that phosphorylation of Smad 5 by integrin αvβ3 and RUNX2 by CD44 signaling, respectively, regulates RANKL expression in human-derived PC3 prostate cancer cells isolated from bone metastasis. We found that RUNX2 intranuclear targeting is mediated by phosphorylation of Smad 5. Indeed, Smad5 knock-down via RNA interference and inhibition of Smad 5 phosphorylation by an αv inhibitor reduced RUNX2 nuclear localization and RANKL expression. Similarly, knockdown of CD44 or RUNX2 attenuated the expression of RANKL. As a result, conditioned media from these cells failed to support osteoclast differentiation in vitro. Immunohistochemistry analysis of tissue microarray sections containing primary prostatic tumor (grade2-4) detected predominant localization of RUNX2 and phosphorylated Smad 5 in the nuclei. Immunoblotting analyses of nuclear lysates from prostate tumor tissue corroborate these observations.Conclusions: Collectively, we show that CD44 signaling regulates phosphorylation of RUNX2. Localization of RUNX2 in the nucleus requires phosphorylation of Smad-5 by integrin αvβ3 signaling. Our results suggest possible integration of two different pathways in the expression of RANKL. These observations imply a novel mechanistic insight into the role of these proteins in bone loss associated with bone metastases in patients with prostate cancer.

In our previous studies, enhancer of zeste homolog 2 (EZH2) has been proven to be a key oncogenic driver in oral squamous cell carcinoma (OSCC). However, the regulatory mechanisms on EZH2 remain poorly understood in OSCC. Here, through multi-transcriptomics, bioinformatics analysis, and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), the co-expression network of long noncoding RNA RC3H2 (RC3H2), microRNA-101-3p (miR-101-3p), and EZH2 were screened and validated as a competing endogenous RNA (ceRNA) mechanism in OSCC. Silencing of RC3H2 inhibited OSCC cell proliferation, colony formation, migration, and invasion in vitro and reduced the expression of EZH2 and H3K27Me3, whereas RC3H2 overexpression significantly promoted OSCC cell growth, colony formation, migration, invasion, and xenograft tumor growth in vivo and increased the expression of EZH2 and H3K27Me3. A fluorescence in situ hybridization (FISH) assay verified that RC3H2 was predominately localized to the cytoplasm. RNA pull-down and luciferase activity assays showed that miR-101-3p was physically bound to RC3H2 as well as EZH2, and its inhibitor reversed the inhibitory effect of RC3H2 knockdown on progression of OSCC. Taken together, our findings demonstrate that RC3H2 as completive endogenous RNA sponging miR-101-3p targets EZH2 and facilitates OSCC cells' malignant behavior.

The recurrence and progression of ameloblastoma are unpredictable. Therefore, we examined the influence of clinical factors on recurrence time and analyzed the clinical factors associated with early recurrence and cancerization. We then developed a staging system to predict early recurrence and cancerization. All of the primary craniofacial ameloblastoma patients treated in Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine were recorded. There were 87 recurrent cases used to create a staging system and tested in a Cox regression analysis for risk factors associated with early recurrence or cancerization following surgery. There were 890 craniofacial ameloblastoma patients, and 72 cases had recurrence. There were also 15 cases with cancerous recurrence. The overall recurrence rate was 9.78%, and the cancer rate was 1.69%. The primary cases were classified into the following 3 stages based on clinicopathological features: stage I, the maximum tumor diameter ≤6 cm; stage II, the maximum diameter of tumor >6 cm or tumor invasion to the maxilla sinus/orbital floor/soft tissue; and stage III, tumor invasion of the skull base or metastasis into regional lymph nodes. When the method of surgery was controlled by partial correlation, the staging had significance with recurrence time (P=0.004). The Cox analysis showed the tumor stage was correlated with recurrence time (P=0.027) and cancerization time (P=0.002). However, the surgical method did not influence the recurrence time when adjusted for cofounding variables. Tumor larger than 6 cm and invasion to soft tissues or adjacent anatomical structures are associated with early recurrence. This staging system can be used to predict the risk factors of early recurrence and cancerization in ameloblastoma patients.

Background: In our previous study using oligonucleotide microarrays, we revealed that transglutaminase 3 (TGM3) was remarkably down-regulated in head and neck cancer (HNC). However, the potential of TGM3 as a useful biomarker or molecular target for HNC is unclear. Methods: The transcriptional and post-translational status of TGM3 in HNC cell lines and specimens was detected using real-time PCR and western blot analysis. Bisulfate-treated DNA sequencing was used to analyze the molecular mechanism of TGM3 gene silencing. In addition, the effects of TGM3 on the proliferation, colony formation and induction of apoptosis in vitro and tumorigenicity in vivo were investigated through exogenous expression of TGM3 in HNC cells. Immunohistochemistry was used to evaluate TGM3 expression in large HNC samples. Results: TGM3 was down-regulated in HNC samples and cell lines (P < 0.0001). The hypermethylation of a promoter CpG island was one of the mechanisms of silencing the TGM3 gene in HNC. Exogenous expression of TGM3 in HNC cells could inhibit the proliferation and enhance the apoptosis of HNC cells in vitro and suppress tumor growth in vivo. In addition, TGM3 protein levels were strongly associated with the pathological differentiation of HNC tissues (P = 0.0037). Survival analysis revealed that low TGM3 expression was associated with worse overall survival (P = 0.0002), and TGM3 expression level was an independent predictor in patients with HNC. Conclusions: The studies prove that TGM3, as a candidate tumor suppressor, contributes to the carcinogenesis and development of HNC and may serve as a useful biomarker for patients with HNC.