Proteome analysis of the transformation potential of the Epstein-Barr virus-encoded latent membrane protein 1 in nasopharyngeal epithelial cells NP69

Immortalization effect of SV40T lentiviral vectors on canine corneal epithelial cells

Background

Primary canine corneal epithelial cells (CCECs) easily become senescent, and cell proliferation is limited. Therefore, sampling for experimentation requires a large number of animals, which is problematic in terms of animal welfare and fails to maintain the stability of the cells for in vitro analyses.

Results

In this study, CCECs were separated and purified by trypsin and dispase II enzymatic analysis. Next, the cells were immortalized by transfection with a lentiviral vector expressing Simian vacuolating virus 40 large T (SV40T). The immortalized canine corneal epithelial cell line (CCEC-SV40T) was established by serial passages and monoclonal selection. The biological characteristics of CCEC-SV40T cells were evaluated based on the cell proliferation rate, cell cycle pattern, serum dependence, karyotype, and cytokeratin 12 immunofluorescence detection. In addition, we infected CCEC-SV40T cells with Staphylococcus pseudintermedius (S. pseudintermedius) and detected the inflammatory response of the cells. After the CCEC-SV40T cells were passaged continuously for 40 generations, the cells grew in a cobblestone pattern, which was similar to CCECs. The SV40T gene and cytokeratin 12 can be detected in each generation. CCEC-SV40T cells were observed to have a stronger proliferation capacity than CCECs. CCEC-SV40T cells maintained the same diploid karyotype and serum-dependent ability as CCECs. After CCEC-SV40T cells were infected with S. pseudintermedius, the mRNA expression levels of NLRP3, Caspase-1 and proinflammatory cytokines, including IL-1β, IL-6, IL-8 and TNF-α, were upregulated, and the protein levels of MyD88, NLRP3 and the phosphorylation of Iκbα and p65 were upregulated.

Conclusions

In conclusion, the CCEC-SV40T line was successfully established and can be used for in vitro studies, such as research on corneal diseases or drug screening.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03288-3.

LMP1 Up-regulates Calreticulin to Induce Epithelial-mesenchymal Transition via TGF-β/Smad3/NRP1 Pathway in Nasopharyngeal Carcinoma Cells

Background: Latent membrane protein 1 (LMP1) is known as an oncogenic protein encoded by the EBV genome. The purpose of this study was to investigate the mechanism of LMP1-induced cell epithelial-mesenchymal transition (EMT).

Methods: The NP69 cell line of nasopharyngeal epithelial cells with high expression of LMP1 was established to observe the effect of high expression of LMP1 on cell growth, proliferation, cycle, apoptosis, migration and invasion. We used proteomics to screen and identify differentially expressed proteins related to LMP1-mediated epithelial cell transformation. Then, we analyzed the expression and significance of differentially expressed calreticulin (CRT) in nasopharyngeal carcinoma (NPC), and observed the effect of CRT expression on EMT in CNE2 cells of NPC. Finally, the expression of neuropilin-1 (NRP1), which is a protein downstream of the EMT-related signaling pathway TGF-β (transforming growth factor β), was detected.

Results: LMP1 promoted NP69 cells proliferation, inhibited apoptosis and induced EMT. We identified 22 differentially expressed proteins associated with LMP1-induced EMT. Among them, CRT expression level was significantly increased in NPC compared with adjacent tissues, and was interrelated with TNM staging and lymph node metastasis of NPC. After knockdown of CRT expression, the phenomenon of cell EMT was reduced and the ability of cell migration and invasion was weakened. CRT regulated NRP1 expression by affecting SMAD3 phosphorylation.

Conclusion: LMP1 induced cell EMT via TGF-β/Smad3/NRP1 pathway, which promoted migration and invasion of NPC cells.

Deciphering nasopharyngeal carcinoma pathogenesis via proteomics

Introduction: Nasopharyngeal carcinoma (NPC) is a distinct head and neck squamous cell carcinoma in its etiological association of Epstein-Barr virus (EBV) infection, hidden anatomical location, remarkable racial and geographical distribution, and high incidence of locoregional recurrence or metastasis. Thanks to the advancements in proteomics in recent decades, more understanding of the disease etiology, carcinogenesis, and progression has been gained, potentially deciphering the molecular characteristics of the malignancy. Areas covered: In this review, we provide an overview of the proteomic aberrations that are likely involved or drive NPC development and progression, focusing on the contributions of major EBV-encoded factors, intercommunication with environment, protein features of high metastasis and therapy resistance, and protein-protein interactions that allow NPC cells to evade immune recognition and elimination. Finally, multistep carcinogenesis and subtypes of NPC from a proteomic perspective are inquired. Expert commentary: Proteomic studies have covered various aspects involved in NPC pathogenesis, yet much remains to be uncovered. Coherent study designs, optimal conditions for obtaining high-quality data, and compelling interpretation are critical in ensuring the emergence of good science out of NPC proteomics. NPC proteogenomics and proteoform analysis are two promising fields to promote the application of the proteomic findings from bench to bedside.

Transcriptomic but not genomic variability confers phenotype of breast cancer stem cells

Background

Breast cancer stem cells (BCSCs) are considered responsible for cancer relapse and drug resistance. Understanding the identity of BCSCs may open new avenues in breast cancer therapy. Although several discoveries have been made on BCSC characterization, the factors critical to the origination of BCSCs are largely unclear. This study aimed to determine whether genomic mutations contribute to the acquisition of cancer stem-like phenotype and to investigate the genetic and transcriptional features of BCSCs.

Methods

We detected potential BCSC phenotype-associated mutation hotspot regions by using whole-genome sequencing on parental cancer cells and derived serial-generation spheres in increasing order of BCSC frequency, and then performed target deep DNA sequencing at bulk-cell and single-cell levels. To identify the transcriptional program associated with BCSCs, bulk-cell and single-cell RNA sequencing was performed.

Results

By using whole-genome sequencing of bulk cells, potential BCSC phenotype-associated mutation hotspot regions were detected. Validation by target deep DNA sequencing, at both bulk-cell and single-cell levels, revealed no genetic changes specifically associated with BCSC phenotype. Moreover, single-cell RNA sequencing showed profound transcriptomic variability in cancer cells at the single-cell level that predicted BCSC features. Notably, this transcriptomic variability was enriched during the transcription of 74 genes, revealed as BCSC markers. Breast cancer patients with a high risk of relapse exhibited higher expression levels of these BCSC markers than those with a low risk of relapse, thereby highlighting the clinical significance of predicting breast cancer prognosis with these BCSC markers.

Conclusions

Transcriptomic variability, not genetic mutations, distinguishes BCSCs from non-BCSCs. The identified 74 BCSC markers have the potential of becoming novel targets for breast cancer therapy.

Electronic supplementary material

The online version of this article (10.1186/s40880-018-0326-8) contains supplementary material, which is available to authorized users.

Pinicolol B from Antrodia cinnamomea induces apoptosis of nasopharyngeal carcinoma cells

ETHNOPHARMACOLOGICAL RELEVANCE

The medicinal mushroom Antrodia cinnamomea possesses anticancer properties but the active compounds responsible for these effects are mostly unknown.

AIM OF THE STUDY

We aimed to identify novel A. cinnamomea compounds that produce cytotoxic effects on cancer cells.

MATERIALS AND METHODS

Using ethanol extraction and chromatography, we isolated the lanostanoid compound lanosta-7,9(11),24-trien-3β,15α,21-triol (1) from cultured A. cinnamomea mycelium. Cytotoxicity and pro-apoptotic effects of compound 1 were evaluated using the MTS assay and flow cytometry analysis, respectively.

RESULTS

Compound 1 produced cytotoxic effects on the nasopharyngeal carcinoma cell lines TW02 and TW04, with IC₅₀ values of 63.3 and 115.0μM, respectively. On the other hand, no cytotoxic effects were observed on non-tumorigenic nasopharyngeal epithelial cells (NP69). In addition, compound 1 induced apoptosis in TW02 and TW04 cells as revealed by flow cytometry analysis.

CONCLUSIONS

Our results demonstrate for the first time the presence of pinicolol B in A. cinnamomea mycelium and suggest that this compound may contribute to the anticancer effects of A. cinnamomea.

Upregulation of special AT-rich-binding protein 1 by Epstein-Barr virus latent membrane protein 1 in human nasopharyngeal cells and nasopharyngeal cancer

A global regulator of chromatin remodelling and gene expression, special AT-rich-binding protein 1 (SATB1) has been implicated in promotion of growth and metastasis of a number of cancers. Here, we demonstrate that the principal oncogene of Epstein-Barr virus (EBV), latent membrane protein 1 (LMP1) upregulates SATB1 RNA and protein expression in human nasopharyngeal cell lines. Silencing of endogenously expressed SATB1 with specific short hairpin RNA decreases cell proliferation and resistance to apoptosis induced by growth factor withdrawal. Additionally, we provide evidence that LMP1-mediated expression of Survivin, a multifunctional protein involved in promoting cell growth and survival, is mediated at least in part by SATB1 in human nasopharyngeal cells. Finally, we show that SATB1 protein levels are elevated in tissue samples from patients with nasopharyngeal carcinoma (NPC), and are directly correlated with the expression of LMP1. Taken together, our results suggest that SATB1 functions as a pro-metastatic effector of LMP1 signalling in EBV-positive NPC.