Analysis of the differential secretome of nasopharyngeal carcinoma cell lines CNE-2R and CNE-2

Precise targeting of transcriptional co-activators YAP/TAZ annihilates chemoresistant brCSCs by alteration of their mitochondrial homeostasis

Persistence of drug-resistant breast cancer stem cells (brCSCs) after a chemotherapeutic regime correlates with disease recurrence and elevated mortality. Therefore, deciphering mechanisms that dictate their drug-resistant phenotype is imperative for designing targeted and more effective therapeutic strategies. The transcription factor SOX2 has been recognized as a protagonist in brCSC maintenance, and previous studies have confirmed that inhibition of SOX2 purportedly eliminated these brCSCs. However, pharmacological targeting of transcription factors like SOX2 is challenging due to their structural incongruities and intrinsic disorders in their binding interfaces. Therefore, transcriptional co-activators may serve as a feasible alternative for effectively targeting the brCSCs. Incidentally, transcriptional co-activators YAP/TAZ were found to be upregulated in CD44+/CD24-/ALDH+ cells isolated from patient breast tumors and CSC-enriched mammospheres. Interestingly, it was observed that YAP/TAZ exhibited direct physical interaction with SOX2 and silencing YAP/TAZ attenuated SOX2 expression in mammospheres, leading to significantly reduced sphere forming efficiency and cell viability. YAP/TAZ additionally manipulated redox homeostasis and regulated mitochondrial dynamics by restraining the expression of the mitochondrial fission marker, DRP1. Furthermore, YAP/TAZ inhibition induced DRP1 expression and impaired OXPHOS, consequently inducing apoptosis in mammospheres. In order to enhance clinical relevance of the study, an FDA-approved drug verteporfin (VP), was used for pharmacological inhibition of YAP/TAZ. Surprisingly, VP administration was found to reduce tumor-initiating capacity of the mammospheres, concomitant with disrupted mitochondrial homeostasis and significantly reduced brCSC population. Therefore, VP holds immense potential for repurposing and decisively eliminating the chemoresistant brCSCs, offering a potent strategy for managing tumor recurrence effectively.

Targeting breast cancer stem cells in ER-positive breast cancer by repurposing the benzoporphyrin derivative verteporfin as a YAP/TAZ small molecule inhibitor

BACKGROUND

Current treatment strategies for hormone-dependent breast cancers, including adjuvant endocrine therapy, often fail due to persistence of breast cancer stem cells (brCSCs), which are significant contributors to tumor recurrence and treatment resistance. Therefore, gaining deeper insights into the molecular regulators driving breast cancer aggressiveness is important. Moreover, given the complexities and expenses involved in developing new pharmacological agents, the strategic repurposing of existing FDA-approved drugs to target these key molecular pathways presents a compelling approach for identifying novel therapeutic interventions aimed at mitigating tumor refractoriness.

METHODS

The study employs survival analysis from TCGA database, protein expression analyses alongside aldefluor assays, sphere formation efficiency tests to evaluate cellular stemness, and DCFDA analysis combined with antioxidant enzyme assays to investigate redox imbalance in brCSCs. These analyses were conducted following the genetic deletion of YAP/TAZ and pharmacological treatment with verteporfin.

RESULTS

The study demonstrated that transcriptional co-activators YAP/TAZ are significantly upregulated in chemotreated ER+ patient breast tumors and MCF-7 mammospheres, where it was found to interact with the transcription factor SOX2 within the nuclear compartment. Genetic ablation and pharmacological inhibition of YAP/TAZ markedly impaired stemness properties and disrupted redox homeostasis in the mammospheres. Additionally, treatment with verteporfin led to a substantial reduction in the frequency and viability of brCSCs, suggesting their effective eradication.

CONCLUSION

This study highlights the potential of repurposing verteporfin, an FDA-approved drug originally formulated for age-related macular degeneration, as a therapeutic agent for targeting YAP/TAZ-mediated stemness and redox balance in brCSCs, thereby reducing their viability in ER-positive breast cancers.

Application of Proteomics in the Discovery of Radiosensitive Cancer Biomarkers

Radiation therapy remains an important component of cancer treatment. Gene-encoded proteins were the actual executors of cellular functions. Proteomic was a novel technology that can systematically analysis protein composition and measure their levels of change, this was a high throughput method, and were the import tools in the post genomic era. In recent years, rapid progress of proteomic have been made in the study of cancer mechanism, diagnosis, and treatment. This article elaborates current advances and future directions of proteomics in the discovery of radiosensitive cancer biomarkers.

Exosomes in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant epithelial tumor with a unique geographical distribution, primarily prevalent in East Africa and Asia. Although there is an increased understanding of the pathogenesis and risk factors of NPC, prevention and treatment efforts remain limited. Various studies have indicated that exosomes are actively involved in NPC by delivering biomolecules such as non-coding RNAs and proteins to target cells. In this review, we summarize the biological functions of exosomes in NPC and highlight their prospects as diagnostic biomarkers. In NPC, exosomes can manipulate the tumor microenvironment, participate in chemotherapy and radiation resistance, induce immune suppression, promote pathological angiogenesis, and support metastasis, and thus they could also be promising biomarkers. Because exosomes have essential effects and unusual biological properties, they have a promising future in diagnostic monitoring and prognostic evaluation. Although there are technical issues associated with using exosomes in large-scale applications, they have unparalleled advantages in assisting the clinical management of NPC.

The role of Exosomes in the Pathogenesis of Nasopharyngeal Carcinoma and the involved Clinical Application

Exosomes are nanoscale membrane vesicles, which carry biologically active substances of their cell of origin and play an important role in signal transduction and intercellular communication. At present, exosomes have been identified as a promising non-invasive liquid biopsy biomarker in the tissues and circulating blood of nasopharyngeal carcinoma (NPC) and found to participate in regulating pathophysiological process of the tumor. We here review recent insights gained into the molecular mechanisms of exosome-induced cell growth, angiogenesis, metastasis, immunosuppression, radiation resistance and chemotherapy resistance in the development and progression of NPC, as well as the clinical application of exosomes as diagnostic biomarkers and therapeutic agents. We also discuss the limitations and challenges in exosome application. We hope this review may provide some references for the use of exosomes in clinical intervention.

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.

SERPINB2 overexpression inhibited cell proliferation, invasion and migration, led to G2/M arrest, and increased radiosensitivity in nasopharyngeal carcinoma cells

The aim of this study was to evaluate the effect of SERPINB2 on cell proliferation, cell cycle, epithelial-mesenchymal transition (EMT), invasion, migration, and radiosensitivity in nasopharyngeal carcinoma cells. Both CNE2R and CNE2 cells were transfected with pEGFP-N1-SERPINB2. Cell proliferation was measured by MTT assay, cell cycle by flow cytometry, and SERpINB2 expression by quantitative real-time polymerase chain reaction (qRT-PCR). Western blot was carried out to detect the protein expression. In addition, SERPINB2 and β-catenin were located intracellularly using an immunofluorescent assay, and cell migration and invasion were measured by wound healing and Transwell assays, respectively. Radiosensitivity was assessed using colony formation and MTT assays. SERPINB2 expression was downregulated in CNE2R cells. After transfection with pEGFP-N1-SERPINB2, the OD values were decreased, and there was an increased fraction in the G2/M phase. Moreover, SERPINB2 overexpression could inhibit the invasion and migration capabilities of CNE2R and CNE2 cells, with downregulation of vimentin, N-cadherin, nuclear β-catenin, matrix metalloproteinase (MMP)-2 and MMP-9, and upregulation of E-cadherin. Moreover, transfection with the SERPINB2 plasmid reduced the growth rate of CNE2R cells at doses of 2, 4 and 6 Gy, and also decreased the surviving fractions. Overexpression of SERPINB2 could reduce the proliferation, invasion and migration capabilities of CNE2R and CNE2 cells, and led to G2/M arrest via EMT inhibition, and this may be a potential strategy for enhancing the radiation sensitivity of nasopharyngeal carcinoma cells.

Downregulation of CD166 inhibits invasion, migration, and EMT in the radio-resistant human nasopharyngeal carcinoma cell line CNE-2R

Objective: CD166 is known as a tumor stem cell specific marker, associating with tumor metastasis. The purpose of this study was to further discuss CD166 gene on cell proliferation, invasion, metastasis, and the epithelial-mesenchymal transition (EMT) in CNE-2R cell line of nasopharyngeal carcinoma (NPC). Materials and methods: CNE-2R cells were transfected with lentivirus CD166-shRNA, and quantitative reverse transcription polymerase chain reaction (RT-qPCR), and Western blotting were used to confirm the silencing effects. The wound healing test and transwell test were carried out to assess cell invasive and migratory abilities in vitro. With the establishment of xenograft nude mouse model, Western blotting and immunohistochemistry were undertaken to detect the expression level of E-cadherin, N-cadherin, and vimentin. In vivo metastasis detection was carried out by injecting tumor cells into nude mice via the tail vein. Results: The invasive and migratory abilities of CNE-2R cells were significantly reduced after CD166 was downregulated. In addition, silencing of CD166 of CNE-2R cells increased the expression of E-cadherin, while down-regulated the expression of N-cadherin and vimentin. Immunohistochemistry of tumors showed consistent results with in-situ tumor formation experiment. Additionally, the growth of transplanted tumor was inhibited. In addition, in vivo metastasis test proved that knockdown of CD166 suppressed pulmonary metastasis and liver metastasis according to hematoxylin and eosin (H&E) staining. Expression of E-cadherin increased, while expression of N-cadherin and vimentin decreased, as revealed by Western blotting of metastatic lung tumors. Conclusion: Silencing of CD166 in CNE-2R cells evidently inhibited proliferation, invasion, metastasis, and EMT process in vivo and in vitro.

Cofilin-2 Acts as a Marker for Predicting Radiotherapy Response and Is a Potential Therapeutic Target in Nasopharyngeal Carcinoma

Background

The purpose of this study was to determine whether cofilin-2 could serve as a protein marker for predicting radiotherapy response and as a potential therapeutic target in nasopharyngeal carcinoma (NPC).

Material/Methods

Cofilin-2 protein levels in serum and tissue samples from patients with NPC were assessed by sandwich ELISA and IHC. In vitro, cofilin-2 levels in CNE-2R cells were significantly higher than those of CNE-2 cells. Meanwhile, CNE-2R cells were silenced for cofilin-2 to obtain a stable cofilin-2-RNAi-LV3 cell line. Then, cell proliferation, radiosensitivity, invasion and migration abilities, cell cycle, and apoptosis were evaluated by Cell Counting Kit 8 assay (CCK-8), flow cytometry (FCM), clone formation assay, and in vitro.

Results

The secreted levels of the cofilin-2 protein in radioresistant NPC patients were significantly higher than those of radiosensitive cases. After cofilin-2 knockdown in nasopharyngeal carcinoma CNE-2R cells, proliferation was decreased, while apoptosis and radiosensitivity were enhanced; cell cycle distribution was altered, and the transplanted tumors in nude mice grew significantly less.

Conclusions

Overall, our findings suggest that cofilin-2 acts as a marker for predicting radiotherapy response and is a potential therapeutic target in nasopharyngeal carcinoma.

Reduced QSOX1 enhances radioresistance in nasopharyngeal carcinoma

Radioresistance is a major cause leads to treatment failure in nasopharyngeal carcinoma (NPC). In our previous study, we identified that QSOX1 is a differentially expressed protein in NPC cell lines with variable radiosensitivities. The present study aimed to investigate the biological behavior of QSOX1 in nasopharyngeal carcinoma (NPC) and its effect on radiosensitivity. The levels of QSOX1 detected by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) in radioresistant NPC patient sera and tissue samples were markedly lower than those in radiosensitive samples. Small hairpin RNAs (shRNAs) were employed to knock down endogenous QSOX1 expression in CNE-2 cells, and then, radiosensitivity, apoptosis, migration and invasion were assessed using colony formation, Cell Counting Kit-8 (CCK-8), flow cytometry, and transwell assays, respectively. Tumor growth and radioresistance were also evaluated using a xenograft model in nude mice. The shRNA-mediated knockdown of QSOX1 significantly increased cell survival under irradiation (IR) and weakened radiosensitivity, which was likely due to a reduction in the cell apoptosis rate after IR. Moreover, QSOX1 silencing led to the suppression of cellular migration and invasion. Similar results were obtained with the xenograft mouse model. Thus, targeting QSOX1 will provide a new avenue for increasing the sensitivity of NPC to radiotherapy.

Serum CD166: A novel biomarker for predicting nasopharyngeal carcinoma response to radiotherapy

The present study aimed to identify whether CD166 can be used as a biomarker for predicting the response of nasopharyngeal carcinoma (NPC) to radiotherapy. The serum concentration of CD166 in patients with NPC were detected by enzyme-linked immunosorbent assay. The secreted level of CD166 with radioresistant NPC was significantly higher than that with radiosensitive NPC. In vitro, the CD166 positive rate in the CNE2 cell membrane was significantly lower than that in the CNE2R cell membrane. The magnetic-activated cell sorting technology was used to obtain CNE-2R-CD166(+) and CNE-2R-CD166(−) cell lines. Then radiosensitivity, cell proliferation, and apoptosis were assessed using colony formation assay, cell counting kit 8 assay (CCK-8), and flow cytometry, respectively. The radiation sensitivity ratio was 1.28, indicating that the CNE2R-CD166(−) cells had a stronger radiation sensitivity. The result of CCK-8 assay indicated that the survival fraction of CNE2R-CD166(+) cells was significantly higher than that of CNE2R-CD166(−) cells. The apoptotic rate of CNE2R-CD166(+) cells was significantly lower than that of CNE2R-CD166(−) cells. Our data demonstrate that the secreted protein CD166 may be can used as a biomarker for predicting the response of NPC to radiotherapy.