Nuclear expression of CDK4 correlates with disease progression and poor prognosis in human nasopharyngeal carcinoma

Transcriptomic responses of the zearalenone (ZEN)-detoxifying yeast Apiotrichum mycotoxinivorans to ZEN exposure

Zearalenone (ZEN) is a potent oestrogenic mycotoxin that is mainly produced by Fusarium species and is a serious environmental pollutant in animal feeds. Apiotrichum mycotoxinivorans has been widely used as a feed additive to detoxify ZEN. However, the effects of ZEN on A. mycotoxinivorans and its detoxification mechanisms remain unclear. In this study, transcriptomic and bioinformatic analyses were used to investigate the molecular responses of A. mycotoxinivorans to ZEN exposure and the genetic basis of ZEN detoxification. We detected 1424 significantly differentially expressed genes (DEGs), of which 446 were upregulated and 978 were downregulated. Functional and enrichment analyses showed that ZEN-induced genes were significantly associated with xenobiotic metabolism, oxidative stress response, and active transport systems. However, ZEN-inhibited genes were mainly related to cell division, cell cycle, and fungal development. Subsequently, bioinformatic analysis identified candidate ZEN-detoxification enzymes. The Baeyer-Villiger monooxygenases and carboxylesterases, which are responsible for the formation and subsequent hydrolysis of a new ZEN lactone, respectively, were significantly upregulated. In addition, the expression levels of genes related to conjugation and transport involved in the xenobiotic detoxification pathway were significantly upregulated. Moreover, the expression levels of genes encoding enzymatic antioxidants and those related to growth and apoptosis were significantly upregulated and downregulated, respectively, which made it possible for A. mycotoxinivorans to survive in a highly toxic environment and efficiently detoxify ZEN. This is the first systematic report of ZEN tolerance and detoxification in A. mycotoxinivorans. We identified the metabolic enzymes that were potentially involved in detoxifying ZEN in the GMU1709 strain and found that ZEN-induced transcriptional regulation of genes is key to withstanding highly toxic environments. Hence, our results provide valuable information for developing enzymatic detoxification systems or engineering this detoxification pathway in other species.

Clinical implications and molecular mechanisms of Cyclin-dependent kinases 4 for patients with hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) was frequently considered as a kind of malignant tumor with a poor prognosis. Cyclin-dependent kinases (CDK) 4 was considered to be cell-cycle-related CDK gene. In this study, we explored the clinical significance of CDK4 in HCC patients.

Methods

Data of HCC patients were obtained from The Cancer Genome Atlas database (TCGA) and the Gene Expression Omnibus (GEO) database. Kaplan–Meier analysis and Cox regression model were performed to calculate median survival time (MST) and the hazard ration (HR), respectively. The joint-effect analysis and prognostic risk score model were constructed to demonstrate significance of prognosis-related genes. The differential expression of prognostic genes was further validated using reverse transcription-quantitative PCR (RT-qPCR) of 58 pairs of HCC samples.

Results

CDK1 and CDK4 were considered prognostic genes in TCGA and GSE14520 cohort. The result of joint-effect model indicated patients in CDK1 and CDK4 low expression groups had a better prognosis in TCGA (adjusted HR = 0.491; adjusted P = 0.003) and GSE14520 cohort (adjusted HR = 0.431; adjusted P = 0.002). Regarding Kaplan–Meier analysis, high expression of CDK1 and CDK4 was related to poor prognosis in both the TCGA (P < 0.001 and = 0.001 for CDK1 and CDK4, respectively) and the GSE14520 cohort (P = 0.006 and = 0.033 for CDK1 and CDK4, respectively). However, only CDK4 (P = 0.042) was validated in RT-qPCR experiment, while CDK1 (P = 0.075) was not.

Conclusion

HCC patients with high CDK4 expression have poor prognosis, and CDK4 could be a potential candidate diagnostic biomarker for HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02152-w.

TET2 suppresses nasopharyngeal carcinoma progression by inhibiting glycolysis metabolism

Background

Nasopharyngeal carcinoma (NPC) is a common malignant tumor. Ten-eleven translocation (TET) protein 2 (TET2), an evolutionarily conserved dioxygenases, is reported to be involved in various malignant tumor developments. Here, we aim to investigate the effect of TET2 on NPC progress in vitro and in vivo, and its detailed underlying mechanism.

Methods

Real-time PCR and western blotting were used to determine the expression levels of TET1/2/3 in NPC cell lines. The effects of TET2 on NPC progression were evaluated using CCK8 and invasion assays in vitro. Proteins interacted with TET2 in NPC cells were detected by immunoprecipitation and mass spectrometry. The effects of TET2 or pyruvate kinase, muscle (PKM) on glycolysis in NPC cells were examined by detecting glucose uptake and lactate production. The effects of TET2 on NPC progression were evaluated using xenograft tumor model in vivo.

Results

TET2 expression was decreased in NPC cells, and TET2 overexpression inhibited proliferation and invasion of NPC cells, which is independent on TET2’s catalytic activity. In mechanism, TET2 N-terminal domain interacts with PKM in cytoplasm to prevent PKM dimers from translocating into nucleus, suppressing glycolysis in NPC cells, thereby inhibiting proliferation and invasion of NPC cells. Moreover, using xenograft tumor model, we found that TET2 knockout promoted NPC progression and decreased survival rate. However, administration with the inhibitor of PKM, shikonin, decreased the tumor volume of TET2-cas9 group, and increased the survival rate.

Conclusion

TET2 suppresses NPC development through interacting with PKM to inhibit glycolysis.

TIPE1-mediated autophagy suppression promotes nasopharyngeal carcinoma cell proliferation via the AMPK/mTOR signalling pathway

Recent studies have shown that tumour necrosis factor‐α–induced protein 8 like‐1(TIPE1) plays distinct roles in different cancers. TIPE1 inhibits tumour proliferation and metastasis in a variety of tumours but acts as an oncogene in cervical cancer. The role of TIPE1 in nasopharyngeal carcinoma (NPC) remains unknown. Interestingly, TIPE1 expression was remarkably increased in NPC tissue samples compared to adjacent normal nasopharyngeal epithelial tissue samples in our study. TIPE1 expression was positively correlated with that of the proliferation marker Ki67 and negatively correlated with patient lifespan. In vitro, TIPE1 inhibited autophagy and induced cell proliferation in TIPE1‐overexpressing CNE‐1 and CNE‐2Z cells. In addition, knocking down TIPE1 expression promoted autophagy and decreased proliferation, whereas overexpressing TIPE1 increased the levels of pmTOR, pS6 and P62 and decreased the level of pAMPK and the LC3B. Furthermore, the decrease in autophagy was remarkably rescued in TIPE1‐overexpressing CNE‐1 and CNE‐2Z cells treated with the AMPK activator AICAR. In addition, TIPE1 promoted tumour growth in BALB/c nude mice. Taken together, results indicate that TIPE1 promotes NPC progression by inhibiting autophagy and inducing cell proliferation via the AMPK/mTOR signalling pathway. Thus, TIPE1 could potentially be used as a valuable diagnostic and prognostic biomarker for NPC.

EVI1 promotes epithelial-to-mesenchymal transition, cancer stem cell features and chemo-/radioresistance in nasopharyngeal carcinoma

BACKGROUND

Aberrant EVI1 expression is frequently reported in cancer studies; however, its role in nasopharyngeal carcinoma (NPC) has not been examined in detail. The aim of the present study is to investigate the involvement of EVI1 in progression and prognosis of NPC.

METHODS

RT-PCR, immunohistochemistry and western blot assays were used to examine the expression of EVI1 in NPC tissues and cell lines. Fluorescence in situ hybridization assay was used to examine the amplification of EVI1 in NPC tissues. The biological effect of EVI1 was determined by both in vitro and in vivo studies. The dual-luciferase reporter assay was performed to confirm that EVI1 bind at E-cadherin andβ-catenin promoters. The ChIP, EMSA, and coimmunoprecipitation combined with mass spectrometry assays were used to analyze the EVI1 regulated proteins.

RESULTS

EVI1 expression level was up-regulated in NPC tissues and cell lines. EVI1 was amplificated in NPC tissues. We observed that EVI1 down-regulation decreased the cell proliferation and invasive capacity of NPC cells in vitro and in vivo. EVI1, snail, and HDAC1 formed a co-repressor complex to repress E-cadherin expression and ultimately contributed to epithelial mesenchymal transition (EMT) phenotype in NPC cells. In another way, EVI1 directly bound at β-catenin promoter and activated its expression. β-catenin mediated EVI1's function on cancer stem cells (CSCs) properties. EVI1 up-regulation predicted unfavorable prognosis and contributed to chemo/radio-resistance in NPC cells. Finally, we constructed arsenic trioxide-loaded nanoparticles (ALNPs) and revealed that ALNPs exerted anti-tumor effect in NPC cells.

CONCLUSIONS

Our data indicated that EVI1 played an oncogenic role in NPC growth and metastasis and that EVI1 might serve as a novel molecular target for the treatment of NPC.

CDK4 and miR-15a comprise an abnormal automodulatory feedback loop stimulating the pathogenesis and inducing chemotherapy resistance in nasopharyngeal carcinoma

Background

In previous investigation, we reported that stably knocking down cyclin-dependent kinase 4(CDK4) induced expression of let-7c, which further suppressed cell cycle transition and cell growth by modulating cell cycle signaling in nasopharyngeal carcinoma (NPC). In this study, we further explored the molecular function and mechanism of CDK4 modulating miRNAs to stimulate cell cycle transition, cell growth, and Cisplatin (DDP) -resistance on in NPC.

Methods

We identified changes in miRNAs by miRNA array and real-time PCR and the effect on DDP after knocking down CDK4 in NPC cells. Further, we investigated the molecular mechanisms by which CDK4 modulated miR-15a in NPC. Moreover, we also explored the role of miR-15a and the effect on DDP in NPC. Finally, we analyzed the correlation of miR-15a and CDK4 expression in NPC tissues.

Results

In addition to let-7 family members, we observed that upregulated expression of miR-15a was significantly induced in CDK4-suppressed NPC cells. Further, we found that knocking down CDK4 suppressed c-Myc expression, and the latter directly suppressed the expression of miR-15a in NPC. Furthermore, miR-15a as a tumor suppressor antagonized CDK4 repressing cell cycle progression and cell growth in vitro and in vivo and induced the sensitivity of cells to DDP by regulating the c-Myc/CCND1/CDK4/E2F1 pathway in NPC. Finally, miR-15a was negatively weak correlated with the expression of CDK4 in NPC.

Conclusions

Our studies demonstrate that CDK4 and miR-15a comprise an abnormal automodulatory feedback loop stimulating the pathogenesis and inducing chemotherapy resistance in NPC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2277-2) contains supplementary material, which is available to authorized users.

Identification of a microRNA signature associated with risk of distant metastasis in nasopharyngeal carcinoma

Purpose

Despite significant improvement in locoregional control in the contemporary era of nasopharyngeal carcinoma (NPC) treatment, patients still suffer from a significant risk of distant metastasis (DM). Identifying those patients at risk of DM would aid in personalized treatment in the future. MicroRNAs (miRNAs) play many important roles in human cancers; hence, we proceeded to address the primary hypothesis that there is a miRNA expression signature capable of predicting DM for NPC patients.

Methods and results

The expression of 734 miRNAs was measured in 125 (Training) and 121 (Validation) clinically annotated NPC diagnostic biopsy samples. A 4-miRNA expression signature associated with risk of developing DM was identified by fitting a penalized Cox Proportion Hazard regression model to the Training data set (HR 8.25; p < 0.001), and subsequently validated in an independent Validation set (HR 3.2; p = 0.01). Pathway enrichment analysis indicated that the targets of miRNAs associated with DM appear to be converging on cell-cycle pathways.

Conclusions

This 4-miRNA signature adds to the prognostic value of the current “gold standard” of TNM staging. In-depth interrogation of these 4-miRNAs will provide important biological insights that could facilitate the discovery and development of novel molecularly targeted therapies to improve outcome for future NPC patients.

miR-16 induction after CDK4 knockdown is mediated by c-Myc suppression and inhibits cell growth as well as sensitizes nasopharyngeal carcinoma cells to chemotherapy

Cyclin-dependent kinase 4 (CDK4) is a member of cyclin-dependent kinase family which regulates G1 to S cell cycle transition. CDK4 activity is increased in many tumor types. Here, we report a negative automodulatory feedback loop between CDK4 and miR-16 that regulates cell cycle progression in nasopharyngeal carcinoma (NPC). By miRNA array and real-time PCR, we identified upregulation of tumor suppressor miR-16a, which inhibited cell cycle progression and sensitized NPC cells to chemotherapy. CDK4 knockdown reduced the expression of c-Myc, the latter of which directly suppresses the miR-16 expression by directly binding to the miR-16 promoter. Moreover, we found that miR-16 upregulation could reduce CDK4 expression by repressing CCND1 and thus forms a feedback loop via the CDK4/c-Myc/miR-16/CCND1 pathway. Finally, miR-16 was negatively correlated with CDK4 expression in NPC biopsies. In summary, our results define a double-negative feedback loop involving CDK4 and miR-16 mediated by c-Myc that modulates NPC cell growth and chemotherapy sensitivity.

The expression of microRNA-34a is inversely correlated with c-MET and CDK6 and has a prognostic significance in lung adenocarcinoma patients

We aimed to establish whether the expression of microRNA-34a (miR-34a) is correlated with that of c-MET and G1 phase regulators such as cyclin dependent kinase (CDK) 4, CDK6, and cyclin D (CCND) 1 in non-small cell lung cancer (NSCLC), and whether a relationship exists between miR-34a expression and both clinicopathologic factors and recurrence-free survival (RFS). For 58 samples archived from NSCLC patients, we measured the expression of miR-34a and c-MET, CDK4/6, and CCND1 by quantitative RT-PCR and assessed the relationship between miR-34a expression, clinicopathological factors, and RFS. The expression of miR-34a was significantly lower in squamous cell tumors (P < 0.001) and in tumors associated with lymphatic invasion (P = 0.001). We found significant inverse correlations between miR-34a and c-MET (R = -0.316, P = 0.028) and CDK6 expression (R = -0.4582, P = 0.004). RFS were longer in adenocarcinoma patients with high miR-34a expression than in those with low miR-34a expression (55.6 vs. 21.6 months; P = 0.020). With univariate analysis, statistically significant prognostic factors for RFS in adenocarcinoma patients were miR-34a expression (Relative risk (RR), 8.14; P = 0.049), TNM stage (RR, 13.55; P = 0.001), LN metastasis (RR, 4.19; P = 0.043), and the presence of lymphatic invasion (RR, 7.05; P = 0.015). In multivariate analysis, only miR-34a was prognostic for RFS (RR, 11.5; P = 0.027). miR-34a expression was inversely correlated with that of c-MET and CDK6 in NSCLC, and had prognostic significance for RFS, especially in adenocarcinoma patients.

Oncogene mutational profile in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a common tumor in Southern China, but the oncogene mutational status of NPC patients has not been clarified. Using time-of-flight mass spectrometry, 238 mutation hotspots in 19 oncogenes were examined in 123 NPC patients. The relationships between mutational status and clinical data were assessed with a χ² or Fisher’s exact test. Survival analysis was performed using the Kaplan–Meier method with the log-rank test. In 123 patients, 21 (17.1%) NPC tumors were positive for mutations in eight oncogenes: six patients had PIK3CA mutations (4.9%), five NRAS mutations (4.1%), four KIT mutations (3.3%), two PDGFRA mutations (1.6%), two ABL mutations (1.6%), and one with simultaneous mutations in HRAS, EGFR, and BRAF (1%). Patients with mutations were more likely to relapse or develop metastasis than those with wild-type alleles (P=0.019). No differences or correlations were found in other clinical characteristics or in patient survival. No mutations were detected in oncogenes AKT1, AKT2, CDK, ERBB2, FGFR1, FGFR3, FLT3, JAK2, KRAS, MET, and RET. These results demonstrate an association between NPC and mutations in NRAS, KIT, PIK3CA, PDGFRA, and ABL, which are associated with patient relapse and metastasis.