Downregulation of RNA binding motif protein 17 expression inhibits proliferation of hypopharyngeal carcinoma FaDu cells.
ABSTRACT: RNA binding motif protein 17 (RBM17) is a protein-coding gene. The protein encoded by RBM17 is involved in the regulation of alternative splicing and is overexpressed in cancer. The present study aimed to determine the effect of RBM17-knockdown in hypopharyngeal carcinoma FaDu cells using the lentivirus-mediated shRNA method. Cell proliferation was detected by an MTT assay. Flow cytometry analysis was used to determine cell cycle distribution and apoptosis. The results of the present study demonstrated that RBM17 expression was significantly decreased in FaDu cells infected with lentivirus-shRNA. Knockdown of RBM17 expression by shRNA significantly reduced cell proliferation, augmented cell apoptosis and arrested cells at the G2/M phase in FaDu cells. The results of the present study indicate that RBM17 serves a notable role in cell proliferation, cell cycle progression and apoptosis of hypopharyngeal carcinoma cells.
Project description:The T-box transcription factor family member TBX3 has been demonstrated to participate in the development of various types of cancer, including head and neck squamous cell carcinoma. However, little is currently known about its role in hypopharyngeal carcinoma. In the present study, the involvement of TBX3 in hypopharyngeal carcinoma was investigated. Immunohistochemical assays revealed that TBX3 levels were increased in hypopharyngeal carcinoma compared with normal tissue samples, accompanied by upregulated N-cadherin and downregulated E-cadherin. Lentivirus-mediated TBX3 knockdown efficiently suppressed its expression and inhibited the proliferation of FaDu cells. The opposite was observed in TBX3-overexpressing FaDu cells. These results indicate that TBX3 is essential for FaDu cell proliferation. Furthermore, TBX3 silencing led to a disturbance of the cell cycle, leading to a decrease in the G1 phase and an increase in the S phase. In addition, apoptosis was enhanced following TBX3 knockdown. The present results suggest TBX3 as a potential therapeutic target in hypopharyngeal carcinoma.
Project description:Statins are used widely to lower serum cholesterol and the incidence of cardiovascular diseases. Growing evidence shows that statins also exhibit beneficial effects against cancers. In this study, we investigated the molecular mechanisms involved in lovastatin-induced cell death in Fadu hypopharyngeal carcinoma cells. Lovastatin caused cell cycle arrest and apoptosis in FaDu cells. Lovastatin increased p21(cip/Waf1) level while the survivin level was decreased in the presence of lovastatin. Survivin siRNA reduced cell viability and induced cell apoptosis in FaDu cells. Lovastatin induced phosphorylation of AMP-activated protein kinase (AMPK), p38 mitogen-activated protein kinase (MAPK) and transcription factor p63. Lovastatin also caused p63 acetylation and increased p63 binding to survivin promoter region in FaDu cells. AMPK-p38MAPK signaling blockade abrogated lovastatin-induced p63 phosphorylation. Lovastatin's enhancing effect on p63 acetylation was reduced in HDAC3- or HDAC4- transfected cells. Moreover, transfection of cells with AMPK dominant negative mutant (AMPK-DN), HDAC3, HDAC4 or p63 siRNA significantly reduced lovastatin's effects on p21(cip/Waf1) and survivin. Furthermore, lovastatin inhibited subcutaneous FaDu xenografts growth in vivo. Taken together, lovastatin may activate AMPK-p38MAPK-p63-survivin cascade to cause FaDu cell death. This study establishes, at least in part, the signaling cascade by which lovastatin induces hypopharyngeal carcinoma cell death.
Project description:Hypopharyngeal squamous cell carcinoma (HSCC) is a malignant tumor found in the head and neck region. Lactate receptor 1, also known as G protein?coupled receptor81 (GPR81), has been reported to play a vital role in cancer growth and metabolism. However, the function of GPR81 in HSCC remains largely unknown. The present study investigated the effect of GPR81 on cell survival and GPR81?mediated energy metabolism under cisplatin treatment in HSCC. GPR81 knockdown reduced the proliferation and invasion of the human HSCC cell line FaDu. Furthermore, GPR81 silencing combined with cisplatin treatment increased the expression of translocase of outer mitochondrial membrane 20 at the mRNA and protein levels (P<0.05). mRNA and protein expression of phosphofructokinase 1 in mRNA appeared to be downregulated in GPR81 knockdown FaDu cells treated with cisplatin, although this was not statistically significant. GPR81 silencing and cisplatin challenge showed no significant upregulation compared with the control, but significant downregulation in mRNA and protein levels compared with the shRNA?scramble group. Apoptosis was measured by flow cytometry with annexin V and 7?aminoactinomycin D. GPR81 silencing and cisplatin led to an increased apoptotic rate. Moreover, absence of GPR81 combined with cisplatin exposure increased caspase?3 expression and decreased Bcl?2 levels. The results of the present study suggested that GPR81 and cisplatin sensitivity played an important role in HSCC growth and metabolism.
Project description:Hypopharyngeal squamous cell carcinoma (HSCC) has the worst prognosis among head and neck cancers. Cisplatin (DDP)-based chemotherapy is an important part of multimodal treatments. However, resistance to DDP severely impairs the effectiveness of chemotherapy for HSCC. Chloroquine (CQ) has been reported to enhance the effectiveness of chemotherapy and radiotherapy in liver, pancreas, breast, prostate and colon tumors, but it is unclear whether CQ could increase the efficacy of DDP for treating HSCC. We inoculated BALB/c nude mice with a subcutaneous injection of human hypopharyngeal FaDu cells to generate our animal model. Mice were randomly divided into 4 groups and treated with vehicle control, CQ (60 mg/kg/day), DDP (5 mg/kg/6 days), or a combination of DDP and CQ. Tumor growth and survival of the mice were monitored. We found that CQ inhibited autophagy and increased DDP-induced apoptosis in the xenograft mouse model. CQ enhanced the efficacy of DDP, resulting in decreased tumor growth and prolonged survival of the mice. To test whether blocking autophagy enhanced the efficacy of DDP, FaDu cells were infected with lentiviral shRNA to Beclin-1 and inoculated into the flanks of nude mice. Inhibition of autophagy markedly enhanced the DDP-induced antitumor effect. Our study suggests that the addition of CQ to DDP-based chemotherapy could be a potential therapeutic strategy for treating HSCC, and the inhibition of autophagy may contribute to chemotherapy sensitization in HSCC.
Project description:BACKGROUND:Hepatocellular carcinoma (HCC) is one of the most lethal and malignant tumours worldwide. New therapeutic targets for HCC are urgently needed. CYCLOPS (copy number alterations yielding cancer liabilities owing to partial loss) genes have been noted to be associated with cancer-targeted therapies. Therefore, we intended to explore the effects of the CYCLOPS gene RBM17 on HCC oncogenesis to determine if it could be further used for targeted therapy. METHODS:We collected data on 12 types of cancer from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) queries for comparison with adjacent non-tumour tissues. RBM17 expression levels, clinicopathological factors and survival times were analysed. RNAseq data were downloaded from the Encyclopaedia of DNA Elements database for molecular mechanism exploration. Two representative HCC cell models were built to observe the proliferation capacity of HCC cells when RBM17 expression was inhibited by shRBM17. Cell cycle progression and apoptosis were also examined to investigate the pathogenesis of RBM17. RESULTS:Based on 6,136 clinical samples, RBM17 was markedly overexpressed in most cancers, especially HCC. Moreover, data from 442 patients revealed that high RBM17 expression levels were related to a worse prognosis. Overexpression of RBM17 was related to the iCluster1 molecular subgroup, TNM stage, and histologic grade. Pathway analysis of RNAseq data suggested that RBM17 was involved in mitosis. Further investigation revealed that the proliferation rates of HepG2 (P = 0.003) and SMMC-7721 (P = 0.030) cells were significantly reduced when RBM17 was knocked down. In addition, RBM17 knockdown also arrested the progression of the cell cycle, causing cells to halt at the G2/M phase. Increased apoptosis rates were also found in vitro. CONCLUSION:These results suggest that RBM17 is a potential therapeutic target for HCC treatment.
Project description:Expression of HIF-1a or Twist1 or Bmi1 in human hypopharyngeal cancer cell line FADU results in the drift of transcriptome profile from an epithelial cell-like signature to a mesenchymal stem cell-like signature. Stable transfection of pHA-HIF1a(dODD), pFLAG-Twist1 or pcDNA3-Bmi1 in FADU cell and analyzed the transcriptome by cDNA microarray. FADU transfected with pcDNA3.1 empty vector was used as a control of experiment.
Project description:Purpose:The expression of programmed death-ligand 1 (PD-L1) is common in various solid human cancers and it is an important therapeutic target. However, the expression pattern, clinical significance and potential mechanism of PD-L1 in hypopharyngeal squamous cell carcinoma (HSCC) are still lacking. Methods:PD-L1 expression in HSCC tumor tissues and paired adjacent hypopharyngeal mucosal tissues was detected using immunohistochemistry assay, and the clinical significance of PD-L1 in HSCC was characterized. In vitro assays including cell viability assays, migration assays, invasion assays as well as Western blot assays were performed to illuminate the biological functions and underlying molecular mechanisms of PD-L1 in HSCC development. Results:PD-L1 expression was detected in HSCC samples but we found no positive expression in matched normal hypopharyngeal mucosal tissues. The levels of PD-L1 expression were significantly correlated with advanced clinical progression and poor patient survival. Multivariable analysis of Cox model showed that PD-L1 expression was an independent predictor for the prognosis of HSCC patients. Functional experiments showed that the ectopic expression of PD-L1 markedly influenced the proliferation, migration and invasion of FaDu cells in vitro. Mechanistically, investigations demonstrated that PD-L1 could promote the epithelial-mesenchymal transition of FaDu cells. Meanwhile, PD-L1 knockdown inhibited, while PD-L1 overexpression activated the Akt-mTOR signaling pathway in FaDu cells. The EMT induced by PD-L1 overexpression could be reversed by the Akt inhibitor. Conclusion:In summary, the expression of PD-L1 can act as a significant biomarker for the adverse clinicopathological features and poor prognosis of patients with HSCC. PD-L1 can promote the proliferation, migration and invasion of FaDu cells and consequently enhance the aggressiveness. Moreover, PD-L1 induces EMT through AKT-mTOR signaling pathway. These suggest that PD-L1 has important tumor-intrinsic functions independent of its immunopathogenic effects.
Project description:Expression of HIF-1a or Twist1 or Bmi1 in human hypopharyngeal cancer cell line FADU results in the drift of transcriptome profile from an epithelial cell-like signature to a mesenchymal stem cell-like signature. Overall design: Stable transfection of pHA-HIF1a(dODD), pFLAG-Twist1 or pcDNA3-Bmi1 in FADU cell and analyzed the transcriptome by cDNA microarray. FADU transfected with pcDNA3.1 empty vector was used as a control of experiment.
Project description:BACKGROUND: Cetuximab is often combined with radiotherapy in advanced SCCHN. Alternative routes bypassing inhibition of EGFR with cetuximab may overshadow the efficacy of this combination. We undertook this study to investigate a possible role of dasatinib in this scenario. METHODS: The SCC5, SCC25, SCC29, FaDu and A431 cell lines were assessed in vitro for cell proliferation under cetuximab and dasatinib treatments. In FaDu and A431 cells, dasatinib plus cetuximab resulted in higher proliferation than cetuximab alone. Then, FaDu and A431 cells were implanted into subcutaneous tissue of athymic mice that were irradiated with 30?Gy in 10 fractions over 2 weeks, and treated with cetuximab and dasatinib. Tumour growth, DNA synthesis and angiogenesis were determined. The EGFR, RAS-GTP activity, phosphorylated AKT, ERK1/2, SRC protein levels and VEGF secretion were determined in vitro. RESULTS: The addition of dasatinib to cetuximab and radiotherapy increased tumour growth, DNA synthesis and angiogenesis that were associated with RAS, AKT and ERK1/2 activation, and SRC inhibition in FaDu and A431 cells. CONCLUSIONS: In xenografts derived from these two cell lines, dasatinib did not improve the efficacy of cetuximab combined with radiotherapy. On the contrary, it worsened tumour control achieved by the combination of these two treatments.
Project description:We investigated Licochalcone-A (Lico-A)-induced apoptosis and the pathway underlying its activity in a pharyngeal squamous carcinoma FaDu cell line. Lico-A purified from root of Glycyrrhiza inflata had cytotoxic effects, significantly increasing cell death in FaDu cells. Using a cell viability assay, we determined that the IC50 value of Lico-A in FaDu cells was approximately 100?µM. Chromatin condensation was observed in FaDu cells treated with Lico-A for 24?h. Consistent with this finding, the number of apoptotic cells increased in a time-dependent manner when FaDu cells were treated with Lico-A. TRAIL was significantly up-regulated in Lico-A-treated FaDu cells in a dose-dependent manner. Apoptotic factors such as caspases and PARP were subsequently activated in a caspase-dependent manner. In addition, levels of pro-apoptotic factors increased significantly in response to Lico-A treatment, while levels of anti-apoptotic factors decreased. Lico-A-induced TRAIL expression was mediated in part by a MAPK signaling pathway involving ERK1/2 and p38. In xenograft mouse model, Lico-A treatment effectively suppressed the growth of FaDu cell xenografts by activating caspase-3, without affecting the body weight of mice. Taken together, these data suggest that Lico-A has potential chemopreventive effects and should therefore be developed as a chemotherapeutic agent for pharyngeal squamous carcinoma.