Distant metastasis accompanied by angiogenesis is the main cause of nasopharyngeal carcinoma (NPC)-related death. Nuclear exosomes (nEXOs) are potential tumour biomarkers. High mobility group box 3 (HMGB3), a nuclear protein, is known to be overexpressed in cancers. However, its role in NPC has not been elucidated. Here, we explore for the first time the function of nEXO HMGB3 in tumour angiogenesis involved in NPC metastasis using a series of in vitro experiments with NPC cell lines and clinical specimens and in vivo experiments with tumour xenograft zebrafish angiogenesis model. We found a high expression of HMGB3 in NPC, accompanied by the formation of micronuclei, to be associated with metastasis. Furthermore, the NPC-secreted HMGB3 expression was associated with tumour angiogenesis. Moreover, HMGB3-containing nEXOs, derived from the micronuclei of NPC cells, were ingested by the human umbilical vein endothelial cells (HUVECs), and accelerated angiogenesis in vitro and in vivo. Importantly, western blotting and flow cytometry analysis showed that circulating nEXO HMGB3 positively correlated with NPC metastasis. In summary, nEXO HMGB3 can be a significant biomarker of NPC metastasis and provide a novel basis for anti-angiogenesis therapy in clinical metastasis.

Circular RNAs (circRNA) are special noncoding RNAs. They are widely present, but with unknown functions. Recent studies have shown that many endogenous circRNAs have sponge function to absorb microRNAs (miRNA). They can regulate target gene messenger RNA expression and play important roles in many biological processes. However, expression profile and function of circRNAs in human tongue squamous cell carcinoma (TSCC) have not been reported. High-throughput sequencing was performed to identify and annotate from three TSCC tissues and adjacent tissues. A separate set (n = 20) of human TSCCs and corresponding adjacent tissues were subjected to reverse-transcription polymerase chain reaction (RT-PCR) for validation of circRNAs expression profile. Gene Ontology (GO) functional analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and circRNA-miRNA network analysis were also performed to predict the function of circRNA in TSCC. A total of 12 156 circRNAs were identified and annotated, most of the circRNAs were novel (n = 6231) and exonic (62.09%). Statistical analysis revealed 322 differentially expressed (DE) circRNAs. RT-PCR results showed that circRNA expression in TSCC was higher than that in adjacent tissues. GO functional analysis, KEGG pathway analysis, and circRNA-miRNA network analysis all showed that circRNAs correlated with tumor development and progression to a certain extent. The current study is the first to systematically characterize and annotate circRNA expression in TSCC, the majority were novel circRNAs. Some host genes of the DE circRNAs were involved in tumor signaling pathway and had complicated correlations with tumor-relevant miRNAs, indicating that circRNAs might be promoted development and progression of TSCC. K E Y W O R D S circular RNA, high-throughput sequencing, microRNA, noncoding RNA, tongue squamous cell carcinoma J Cell Biochem. 2019;120:4102-4112. wileyonlinelibrary.com/journal/jcb 4102 |

HCLS1-associated protein X-1 (HAX-1) is highly expressed or overexpressed in various types of human tumor, and its overexpression is associated with cancer metastasis and cellular proliferation. However, the precise molecular mechanism involved in HAX-1-associated proliferation and metastasis in hypopharyngeal carcinoma is unknown. The present study aimed to investigate the role of HAX-1 in the metastasis and proliferation of hypopharyngeal carcinoma. Reverse transcription-quantitative polymerase chain reaction analysis and western blotting indicated that HAX-1 was overexpressed in hypopharyngeal carcinoma specimens. MTT, clone formation and transwell assays were performed to detect the effects of HAX-1 knockdown or overexpression on the major oncogenic properties of the FaDu hypopharyngeal carcinoma cell line. Downregulation of HAX-1 was observed to significantly suppress cellular proliferation, migration and clonal. By contrast, overexpression of HAX-1 significantly promoted cellular proliferation, migration and clonal formation. Furthermore, HAX-1 knockdown markedly suppressed epithelial-mesenchymal transition. In conclusion, HAX-1 is a potential oncogene, and may promote the tumorigenesis and progression of hypopharyngeal carcinoma, as well as serve as a valuable molecular target for the treatment of hypopharyngeal carcinoma.

Inherited hearing loss is associated with gene mutations that result in sensory hair cell (HC) malfunction. HC structure is defined by the cytoskeleton, which is mainly composed of actin filaments and actin-binding partners. LIM motif-containing protein kinases (LIMKs) are the primary regulators of actin dynamics and consist of two members: LIMK1 and LIMK2. Actin arrangement is directly involved in the regulation of cytoskeletal structure and the maturation of synapses in the central nervous system, and LIMKs are involved in structural plasticity by controlling the activation of the actin depolymerization protein cofilin in the olfactory system and in the hippocampus. However, the expression pattern and the role of LIMKs in mouse cochlear development and synapse function also need to be further studied. We show here that the Limk genes are expressed in the mouse cochlea. We examined the morphology and the afferent synapse densities of HCs and measured the auditory function in Limk1 and Limk2 double knockout (DKO) mice. We found that the loss of Limk1 and Limk2 did not appear to affect the overall development of the cochlea, including the number of HCs and the structure of hair bundles. There were no significant differences in auditory thresholds between DKO mice and wild-type littermates. However, the expression of p-cofilin in the DKO mice was significantly decreased. Additionally, no significant differences were found in the number or distribution of ribbon synapses between the DKO and wild-type mice. In summary, our data suggest that the Limk genes play a different role in the development of the cochlea compared to their role in the central nervous system.

The cell surface glycoprotein Trop2 is overexpressed in various types of epithelial cancer. Laryngeal carcinoma is one of the most common types of head and neck cancer and in a previous study, the expression of Trop2 in laryngeal squamous cell carcinoma (LSCC) was identified as an independent prognostic factor. However, the biological significance of Trop2 in LSCC development remains unclear. In the current study, Trop2 protein expression in fresh LSCC tissue and paracancerous tissue was investigated using western blotting. Trop2 in the Hep2 laryngeal cell line was subsequently suppressed by transfection with small interfering RNA (siRNA). The effects of knockdown of Trop2 on cell viability, migration, invasiveness and ERK/MAPK pathway activity were investigated in the current study. The expression of Trop2 in fresh LSCC tissue was demonstrated to be significantly greater than that in paracancerous tissue. Trop2 expression was also identified to be required for proliferation, migration and invasiveness of Hep2 laryngeal carcinoma cells, as all were blocked by siRNA-mediated Trop2 inhibition. Notably, the ERK/MAPK signaling pathway and cell cycle factor, cyclin D1, were identified to be suppressed following the knockdown of Trop2 in Hep2 cells. These observations suggest that Trop2 serves an oncogenic role in LSCC and has potential as a therapeutic target.