CerS6 regulates cisplatin resistance in oral squamous cell carcinoma by altering mitochondrial fission and autophagy.

Chemoresistance remains a challenge in the effective treatment of solid tumors, including oral squamous cell carcinoma (OSCC). Mitochondrial dynamics and autophagy have recently been implicated in the chemoresistance of cancer cells. The neutralization of ceramide is also associated with multidrug resistance, and ceramide synthase 6 (CerS6) is known to induce apoptosis. However, whether CerS6 regulates chemoresistance in OSCC is not clearly understood. Therefore, we investigated the role of CerS6 in the susceptibility of OSCC cells to cisplatin. In this study, we observed that cisplatin-resistant OSCC cells process lower levels of fission-state mitochondria and cell apoptosis than cisplatin-sensitive cells, and autophagy was activated in cisplatin-resistant OSCC cells. We found lower CerS6 expression in cisplatin-resistant OSCC cells. Overexpression of CerS6 with lentivirus-encoded CerS6 complementary DNA in cisplatin-resistant OSCC cells increased cisplatin sensitivity. Overexpression of CerS6 enhanced mitochondrial fission and apoptosis and attenuated cisplatin-induced autophagy in cisplatin-resistant OSCC cells. Further investigation indicated that CerS6 might function through altering calpain expression to enhance cisplatin sensitivity. Cisplatin-resistant OSCC cells xenografted onto a nude mouse model confirmed that CerS6 enhanced cisplatin chemotherapy sensitivity to reduce tumor volume. These data indicate that CerS6 could mediate an effective response to cisplatin in chemoresistant OSCC.

lncRNA MALAT1 mediates osteogenic differentiation of bone mesenchymal stem cells by sponging miR-129-5p.

Background: Bone mesenchymal stem cells (BMSCs) have good osteogenic differentiation potential and have become ideal seed cells in bone tissue engineering. However, the osteogenic differentiation ability of BMSCs gradually weakens with age, and the regulatory mechanism is unclear. Method: We conducted a bioinformatics analysis, dual-luciferase reporter (DLR) experiment, and RNA binding protein immunoprecipitation (RIP) to explore the hub genes that may affect BMSC functions. Results: The expression level of long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (Malat1) was significantly higher in the BMSCs from elderly than younger mice, while miR-129-5p showed the opposite trend. The results of alkaline phosphatase staining, quantitative reverse transcription PCR and western blot experiments indicated that inhibiting the expression of Malat1 inhibits the osteogenic differentiation of BMSCs. This effect can be reversed by reducing the expression of miR-129-5p. Additionally, DLR and RIP experiments confirmed that Malat1 acts as a sponge for miR-129-5p. Conclusion: Overall, our study findings indicated that lncRNA Malat1 may play a critical role in maintaining the osteoblast differentiation potential of BMSCs by sponging miR-129-5p.

Theaflavin-3, 3'-Digallate Suppresses RANKL-Induced Osteoclastogenesis and Attenuates Ovariectomy-Induced Bone Loss in Mice.

Theaflavin-3, 3'-digallate (TF3) is extracted from black tea and has strong antioxidant capabilities. The aim of this study was to assess the influences of TF3 on osteoclastogenesis and explore the underlying mechanisms. TF3 efficiently decreased receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclast formation and reactive oxygen species (ROS) generation in a dose-dependent manner. Mechanistically, TF3 reduced ROS generation by activating nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream heme oxygenase-1 (HO-1) and also inhibited the mitogen-activated protein kinases (MAPK) pathway. Moreover, micro-computed tomography (CT) analysis, hematoxylin and eosin (H&E) staining, and TRAP staining of the femurs of C57BL/6J female mice showed that TF3 markedly attenuated bone loss and osteoclastogenesis in mice. Immunofluorescence staining, 2',7'-dichlorofluorescein diacetate (DCFH-DA) staining, and measurement of the levels of malonaldehyde (MDA) and superoxide dismutase (SOD) revealed that TF3 increased the expression of Nrf2 and decreased the intracellular ROS level in vivo. These findings indicated that TF3 may have the potential to treat osteoporosis and bone diseases related to excessive osteoclastogenesis via inhibiting the intracellular ROS level.

Construction and analysis of a lncRNA-miRNA-mRNA network based on competitive endogenous RNA reveal functional lncRNAs in oral cancer.

BACKGROUND: A growing evidence suggests that long non-coding RNAs (lncRNAs) can function as a microRNA (miRNA) sponge in various diseases including oral cancer. However, the pathophysiological function of lncRNAs remains unclear. METHODS: Based on the competitive endogenous RNA (ceRNA) theory, we constructed a lncRNA-miRNA-mRNA network in oral cancer with the human expression profiles GSE74530 from the Gene Expression Omnibus (GEO) database. We used topological analysis to determine the hub lncRNAs in the regulatory ceRNA network. Then, function enrichment analysis was performed using the clusterProfiler R package. Clinical information was downloaded from The Cancer Genome Atlas (TCGA) database and survival analysis was performed with Kaplan-Meier analysis. RESULTS: A total of 238 potential co-dysregulated competing triples were obtained in the lncRNA-associated ceRNA network in oral cancer, which consisted of 10 lncRNA nodes, 41 miRNA nodes and 122 mRNA nodes. Additionally, we found lncRNA HCG22 exhibiting superior potential as a diagnostic and prognostic marker of oral cancer. CONCLUSIONS: Our findings provide novel insights to understand the ceRNA regulation in oral cancer and identify a novel lncRNA as a potential molecular biomarker.

Identification of key genes and transcription factors in aging mesenchymal stem cells by DNA microarray data.

BACKGROUND: Mesenchymal stem cells (MSCs) are multipotent cells that can be widely used in stem cell therapy. However, few studies have revealed the potential mechanisms of the changes in aging MSC. MATERIALS AND METHODS: In this study, microarray data GSE35955 was downloaded from the Gene Expression Omnibus database. Then limma package in R was used to filtrate differentially expressed genes (DEGs), Transcription factors (TFs) were predicted by DCGL package. After predicting TFs, protein-protein interaction (PPI) network and TF-mediated transcriptional regulation network were constructed. The functional and pathway enrichment analysis of screened DEGs, hub genes and TFs were conducted by the DAVID. RESULTS: Totally 156 up-regulated DEGs and 343 down-regulated DEGs were obtained. 6 hub genes (CTNNB1, PPP2R1A, FYN, MAPK1, PIK3C2A and EP300) were obtained from PPI network. 11 TFs (CREB1, CUX1, EGR1, EP300, FOXC1, HSF2, MEF2A, PLAU, SP1, STAT1 and USF1) for DEGs were predicted and 2 highly scored co-expression relationships (EP300-PPP2R1A and STAT1-FOXC1) were acquired from the TF-mediated transcriptional regulation network. CONCLUSIONS: The discovery of the hub genes, TFs and pathways might contribute to the understanding of genetic and molecular functions of aging-related changes in MSC. Further validation studies on genes and TFs such as CTNNB1, FYN, PPP2R1A, MAPK1, EP300 and related biological processes and pathways, including adherens junction, DNA damage caused from oxidative stress, attribution of telomere, MSC differentiation and epigenetic regulation, are urgent for clinical prevention and treatment.

The effects of three modified Hank's balanced salt solutions on root resorption of late replanted teeth: A pilot study.

PURPOSE: The purpose of this study was to evaluate the effects of replanted rats' teeth that had been soaked in one of three modified Hank's balanced salt solutions (HBSSs) before replantation and after extended extra-oral dry time. MATERIALS AND METHODS: Maxillary right incisors were extracted from 55 Wistar rats and kept dry for 30 or 60 min (n = 5 each). Afterwards, the pulp was extirpated and both the papilla and enamel organ were removed with a scalpel. Each group of teeth was soaked in one of three modified HBSSs or HBSS alone. After 30 min of immersion in solutions, the root canals were dried and filled with calcium hydroxide paste, and the teeth were replanted. After 8 weeks, animals were euthanized; then, specimens were processed as 5 µm-thick serial sections for histological examination and morphometric assessments. RESULTS: The percentages of root resorption for the groups were found to be in the following order: HBSS3 (the bFGF group) > the HBSS only group > HBSS2 (the GSH group) > no soaking (the positive control group) > HBSS1 (the ALN group) for 30 min and the positive control group > the HBSS only group > HBSS2 > HBSS3 > HBSS1 for 60 min. The lowest incidence of resorption was observed in immediately replanted teeth (negative control). CONCLUSIONS: The findings of this study suggest that soaking for 30 min in HBSS containing 1 mM alendronate can significantly inhibit root resorption for avulsed teeth that have been dried for 60 min.