MiR-122-5p regulates erastin-induced ferroptosis via CS in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is a tumor that occurs in the nasopharynx. Although advances in detection and treatment have improved the prognosis of NPC the treatment of advanced NPC remains challenging. Here, we explored the effect of microRNA (miR)-122-5p on erastin-induced ferroptosis in NPC cells and the role of ferroptosis in the development of NPC. The effect of miR-122-5p silencing and overexpression and the effect of citrate synthase on erastin-induced lipid peroxidation in NPC cells was analyzed by measuring the amounts of malondialdehyde, Fe2+, glutathione, and reactive oxygen species and the morphological alterations of mitochondria. The malignant biological behavior of NPC cells was examined by cell counting kit-8, EDU, colony formation, Transwell, and wound healing assays. The effects of miR-122-5p on cell proliferation and migration associated with ferroptosis were examined in vivo in a mouse model of NPC generated by subcutaneous injection of NPC cells. We found that erastin induced ferroptosis in NPC cells. miR-122-5p overexpression inhibited CS, thereby promoting erastin-induced ferroptosis in NPC cells and decreasing NPC cell proliferation, migration, and invasion.

Prognostic Significance of Excision Repair Cross-Complementation Group 1 on Circulating Tumor Cells for Nasopharyngeal Carcinoma.

BACKGROUND: Liquid biopsy, including the detection of circulating tumor cells (CTCs), has emerged as a promising tool for cancer diagnosis and monitoring. However, the prognostic value of CTCs in nasopharyngeal carcinoma (NPC) remains unclear due to the lack of phenotypic characterization. The expression of Excision Repair Cross-Complementation Group 1 (ERCC1) and CTCs epithelial-mesenchymal transition (EMT) have been associated with treatment efficacy. In this study, we aimed to evaluate the prognostic significance of ERCC1 expression on CTCs and their EMT subtypes before treatment in NPC. METHODS: We retrospectively analyzed 108 newly diagnosed locally advanced NPC patients who underwent CanPatrol™ CTC testing between November 2018 and November 2021. CTCs were counted and classified into epithelial, epithelial-mesenchymal hybrid, and mesenchymal subtypes. ERCC1 expression was divided into negative and positive groups. Clinical features and survival outcomes were analyzed. RESULTS: The positive rate of CTCs was 92.6% (100/108), with an ERCC1 positivity rate of 74% (74/100). Further analysis of the subtypes showed that positive ERCC1 on mesenchymal CTCs was associated with a later N stage (P = .01). Positive ERCC1 expression was associated with poor overall survival (OS; P = .039) and disease-free survival (DFS; P = .035). Further analysis of subtypes showed that the positive ERCC1 on mesenchymal-type CTCs was associated with poor OS (P = .012) and metastasis-free survival (MFS; P = .001). CONCLUSION: Our findings suggest that ERCC1 expression on CTCs may serve as a new prognostic marker for NPC patients. Evaluating CTCs subtypes may become an auxiliary tool for personalized and precise treatment.

BackgroundLiquid biopsy, including the detection of circulating tumor cells (CTCs), has emerged as a promising tool for cancer diagnosis and monitoring. However, the prognostic value of CTCs in nasopharyngeal carcinoma (NPC) remains unclear due to the lack of phenotypic characterization. The expression of Excision Repair Cross-Complementation Group 1 (ERCC1) and CTCs epithelial-mesenchymal transition (EMT) have been associated with treatment efficacy. In this study, we aimed to evaluate the prognostic significance of ERCC1 expression on CTCs and their EMT subtypes before treatment in NPC.MethodsWe retrospectively analyzed 108 newly diagnosed locally advanced NPC patients who underwent CanPatrol™ CTC testing between November 2018 and November 2021. CTCs were counted and classified into epithelial, epithelial-mesenchymal hybrid, and mesenchymal subtypes. ERCC1 expression was divided into negative and positive groups. Clinical features and survival outcomes were analyzed.ResultsThe positive rate of CTCs was 92.6% (100/108), with an ERCC1 positivity rate of 74% (74/100). Further analysis of the subtypes showed that positive ERCC1 on mesenchymal CTCs was associated with a later N stage (P = .01). Positive ERCC1 expression was associated with poor overall survival (OS; P = .039) and disease-free survival (DFS; P = .035). Further analysis of subtypes showed that the positive ERCC1 on mesenchymal-type CTCs was associated with poor OS (P = .012) and metastasis-free survival (MFS; P = .001).ConclusionOur findings suggest that ERCC1 expression on CTCs may serve as a new prognostic marker for NPC patients. Evaluating CTCs subtypes may become an auxiliary tool for personalized and precise treatment.

Chitinase 3 like-1 activates the Akt pathway, inducing NF-κB-dependent release of pro-inflammatory cytokines and promoting the proliferative ability in nasopharyngeal carcinoma cells.

BACKGROUND: Chitinase 3 like-1 (CHI3L1) has been reported to function as an oncogene in many types of cancer. However, the biological function of CHI3L1 in nasopharyngeal carcinoma (NPC) remains unknown. METHODS: Differentially expressed genes (DEGs) in NPC tissues in GSE64634 and GSE12452 were downloaded from Gene Expression Omnibus (GEO). CHI3L1, interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α) mRNA expression was examined by qRT-PCR. Cell proliferation was evaluated by CCK-8 and EdU incorporation assays. Western blot analysis was used to measure the changes of CHI3L1, nuclear factor-κappaB (NF-κB), and protein kinase B (Akt) pathways. Gene ontology (GO) enrichment and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway analyses were performed using DAVID database. RESULTS: We identified 3 overlapping DEGs using Draw Venn diagram, among which CHI3L1 was chosen for the following analyses. CHI3L1 was upregulated in NPC tissues and cells. CHI3L1 silencing suppressed inflammatory response by inactivating the NF-κB pathway and inhibited cell proliferation in NPC cells. On the contrary, CHI3L1 overexpression induced inflammatory response by activating the NF-κB pathway and promoted cell proliferation in NPC cells. According to GO and KEGG analyses, CHI3L1 positive regulates Akt signaling and is enriched in the PI3K-Akt pathway. CHI3L1 knockdown inhibited the Akt pathway, and CHI3L1 overexpression activated the Akt pathway in NPC cells. Akt overexpression abolished the effects of CHI3L1 knockdown on inflammatory response, NF-κB pathway, and proliferation in NPC cells. On the contrary, Akt knockdown abolished the effects of CHI3L1 overexpression on inflammatory response, NF-κB pathway, and proliferation in NPC cells. CONCLUSION: CHI3L1 knockdown inhibited NF-κB-dependent inflammatory response and promoting proliferation in NPC cells by inactivating the Akt pathway.

Downregulation of KLF5 by EBER1 via the ERK signaling pathway in EBV-positive nasopharyngeal carcinoma cells: implications for latent EBV infection.

Nasopharyngeal carcinoma (NPC) carcinogenesis and malignant transformation are intimately associated with Epstein-Barr virus (EBV) infection. A zinc-fingered transcription factor known as Krüppel-like factor 5 (KLF5) has been shown to be aberrantly expressed in a number of cancer types. However, little is known about the regulatory pathways and roles of KLF5 in EBV-positive NPC. Our study found that KLF5 expression was significantly lower in EBV-positive NPC than in EBV-negative NPC. Further investigation revealed that EBER1, which is encoded by EBV, down-regulates KLF5 via the extracellular signal-regulated kinase (ERK) signalling pathway. This down-regulation of KLF5 by EBER1 contributes to maintaining latent EBV infection in NPC. Furthermore, we uncovered the biological roles of KLF5 in NPC cells. Specifically, KLF5 may influence the cell cycle, prevent apoptosis, and encourage cell migration and proliferation - all of which have a generally pro-cancer impact. In conclusion, these findings offer novel strategies for EBV-positive NPC patients' antitumour treatment.

FLI1 promotes IFN-γ-induced kynurenine production to impair anti-tumor immunity.

Nasopharyngeal carcinoma (NPC)-mediated immunosuppression within the tumor microenvironment (TME) frequently culminates in the failure of otherwise promising immunotherapies. In this study, we identify tumor-intrinsic FLI1 as a critical mediator in impairing T cell anti-tumor immunity. A mechanistic inquiry reveals that FLI1 orchestrates the expression of CBP and STAT1, facilitating chromatin accessibility and transcriptional activation of IDO1 in response to T cell-released IFN-γ. This regulatory cascade ultimately leads to augmented IDO1 expression, resulting in heightened synthesis of kynurenine (Kyn) in tumor cells. This, in turn, fosters CD8+ T cell exhaustion and regulatory T cell (Treg) differentiation. Intriguingly, we find that pharmacological inhibition of FLI1 effectively obstructs the CBP/STAT1-IDO1-Kyn axis, thereby invigorating both spontaneous and checkpoint therapy-induced immune responses, culminating in enhanced tumor eradication. In conclusion, our findings delineate FLI1-mediated Kyn metabolism as an immune evasion mechanism in NPC, furnishing valuable insights into potential therapeutic interventions.

Comprehensive analysis revealed P4Hs as new biomarkers for prognosis and immunotherapy in head and neck cancer.

Prolyl 4-hydroxylases (P4Hs) are a family of key modifying enzymes in collagen synthesis. P4Hs have been confirmed to be closely associated with tumor occurrence and development. However, the expression of P4Hs in head and neck cancer (HNSC) as well as its relationship with prognosis and tumor immunity infiltration has not yet been analyzed. We investigated the transcriptional expression, survival data, and immune infiltration of P4Hs in patients with HNSC from multiple databases. P4H1-3 expression was significantly higher in HNSC tumor tissues than in normal tissues. Moreover, P4HA1 and P4HA2 were associated with tumor stage, patient prognosis, and immune cell infiltration. P4HA3 was related to patient prognosis and immune cell infiltration. Correlation experiments confirmed that P4HA1 may serve as a prognosis biomarker and plays a role in the progression of nasopharyngeal carcinoma. These findings suggest that P4HA1-3 may be a novel biomarker for the prognosis and treatment of HNSC, which is expected to support the development of new therapies for patients with head and neck tumors and improve patient outcomes.

Targeted blocking of EGFR and GLUT1 by compound H reveals a new strategy for treatment of triple-negative breast cancer and nasopharyngeal carcinoma.

BACKGROUND: Cytoplasmic epidermal growth factor receptor (EGFR) is overexpressed in both nasopharyngeal carcinoma (NPC) and triple-negative breast cancer (TNBC), while clinical outcome and prognosis vary greatly among patients treated with gefitinib, and all patients eventually develop resistance to this agent. Therefore, we propose a new concept for synthesizing multitarget compounds and reveal new therapeutic strategies for NPC and TNBC expressing EGFR. METHODS: Compound H was synthesized in our previous study. Molecular docking, and cell thermal shift assays (CETSAs) and drug affinity responsive target stability(DARTS) were used to confirm the binding of compound H to EGFR and GLUT1. Methylthiazolyldiphenyl-tetrazolium bromide(MTT), annexin V-PE assays, mitochondrial membrane potential (MMP) assays, and animal models were used to evaluate the inhibitory effect of compound H on TNBC cell lines. Energy metabolism tests, Western blotting, and immunofluorescence staining were performed to evaluate the synergistic effects on EGFR- and glucose transporter type 1(GLUT1)-mediated energy metabolism. RESULTS: Compound H can simultaneously act on the EGFR tyrosine kinase ATP-binding site and inhibit GLUT1-mediated energy metabolism, resulting in reductions in ATP, MMP, intra-cellular lactic acid, and EGFR nuclear transfer. The anti-tumor activity of compound H is significantly superior to the combination of GLUT1 inhibitor BAY876 and EGFR inhibitor gefitinib. Compound H has remarkable anti-proliferative effects on TNBC MDA-MB231 cells, and importantly, no obvious toxicity effects of compound H were found in vivo. CONCLUSIONS: Synergistic effects of inhibition of EGFR- and GLUT1-mediated energy metabolism by compound H may present a new strategy for the treatment of TNBC and NPC.

The Role of PTEN in Nasopharyngeal Carcinoma.

Nasopharyngeal carcinoma (NPC) is an aggressive head and neck tumor that is influenced by a variety of molecular factors during its pathogenesis. Among these, the phosphatase and tensin homolog (PTEN) plays a crucial role in regulatory networks. This article systematically reviews the multifaceted functions of PTEN in NPC, including its roles in inhibiting cell proliferation, regulating migration and invasion, promoting autophagy and apoptosis, and influencing resistance to radiotherapy. Molecular factors such as long non-coding RNA, microRNA (miRNA), and circular RNA can modulate PTEN through various pathways, thereby impacting the biological behavior of NPC. In addition, PTEN is involved in regulating the tumor microenvironment of NPC, and its interaction with the Epstein-Barr virus has also recently become a focus of research. A comprehensive understanding of the PTEN regulatory network provides a foundation for future personalized and targeted therapeutic strategies. This study expands our understanding of the pathogenesis of NPC and suggests new directions in the field of tumor biology and NPC treatment.

Targeting Cancer Mitochondria by Inducing an Abnormal Mitochondrial Unfolded Protein Response Leads to Tumor Suppression.

The mitochondrial unfolded protein response (UPRmt) is a pivotal cellular mechanism that ensures mitochondrial homeostasis and cellular survival under stress conditions. This study investigates the role of UPRmt in modulating the response of nasopharyngeal carcinoma cells to cisplatin-induced stress. We report that the inhibition of UPRmt via AEB5F exacerbates cisplatin cytotoxicity, as evidenced by increased lactate dehydrogenase (LDH) release and apoptosis, characterized by a surge in TUNEL-positive cells. Conversely, the activation of UPRmt with oligomycin attenuates these effects, preserving cell viability and reducing apoptotic markers. Immunofluorescence assays reveal that UPRmt activation maintains mitochondrial membrane potential and ATP production in the presence of cisplatin, countering the rise in reactive oxygen species (ROS) and inhibiting caspase-9 activation. These findings suggest that UPRmt serves as a cytoprotective mechanism in cancer cells, mitigating cisplatin-induced mitochondrial dysfunction and apoptosis. The data underscore the therapeutic potential of modulating UPRmt to improve the efficacy and reduce the side effects of cisplatin chemotherapy. This study provides a foundation for future research on the exploitation of UPRmt in cancer treatment, with the aim of enhancing patient outcomes by leveraging the cellular stress response pathways.

Cancer-associated fibroblasts secrete FGF5 to inhibit ferroptosis to decrease cisplatin sensitivity in nasopharyngeal carcinoma through binding to FGFR2.

Cisplatin (DDP)-based chemoradiotherapy is one of the standard treatments for nasopharyngeal carcinoma (NPC). However, the sensitivity and side effects of DDP to patients remain major obstacles for NPC treatment. This research aimed to study DDP sensitivity regulated by cancer-associated fibroblasts (CAFs) through modulating ferroptosis. We demonstrated that DDP triggered ferroptosis in NPC cells, and it inhibited tumor growth via inducing ferroptosis in xenograft model. CAFs secreted high level of FGF5, thus inhibiting DDP-induced ferroptosis in NPC cells. Mechanistically, FGF5 secreted by CAFs directly bound to FGFR2 in NPC cells, leading to the activation of Keap1/Nrf2/HO-1 signaling. Rescued experiments indicated that FGFR2 overexpression inhibited DDP-induced ferroptosis, and CAFs protected against DDP-induced ferroptosis via FGF5/FGFR2 axis in NPC cells. In vivo data further showed the protective effects of FGF5 on DDP-triggered ferroptosis in NPC xenograft model. In conclusion, CAFs inhibited ferroptosis to decrease DDP sensitivity in NPC through secreting FGF5 and activating downstream FGFR2/Nrf2 signaling. The therapeutic strategy targeting FGF5/FGFR2 axis from CAFs might augment DDP sensitivity, thus decreasing the side effects of DDP in NPC treatment.

Nasopharyngeal Carcinoma Cell Lines: Reliable Alternatives to Primary Nasopharyngeal Cells?

Nasopharyngeal carcinoma (NPC) is a type of cancer that originates from the mucosal lining of the nasopharynx and can invade and spread. Although contemporary chemoradiotherapy effectively manages the disease locally, there are still challenges with locoregional recurrence and distant failure. Therefore, it is crucial to have a deeper understanding of the molecular basis of NPC cell movement in order to develop a more effective treatment and to improve patient survival rates. Cancer cell line models are invaluable in studying health and disease and it is not surprising that they play a critical role in NPC research. Consequently, scientists have established around 80 immortalized human NPC lines that are commonly used as in vitro models. However, over the years, it has been observed that many cell lines are misidentified or contaminated by other cells. This cross-contamination leads to the creation of false cell lines that no longer match the original donor. In this commentary, we discuss the impact of misidentified NPC cell lines on the scientific literature. We found 1159 articles from 2000 to 2023 that used NPC cell lines contaminated with HeLa cells. Alarmingly, the number of publications and citations using these contaminated cell lines continued to increase, even after information about the contamination was officially published. These articles were most commonly published in the fields of oncology, pharmacology, and experimental medicine research. These findings highlight the importance of science policy and support the need for journals to require authentication testing before publication.

Epstein-Barr virus-driven metabolic alterations contribute to the viral lytic reactivation and tumor progression in nasopharyngeal carcinoma.

Metabolic reprogramming induced by Epstein-Barr virus (EBV) often mirrors metabolic changes observed in cancer cells. Accumulating evidence suggests that lytic reactivation is crucial in EBV-associated oncogenesis. The aim of this study was to explore the role of metabolite changes in EBV-associated malignancies and viral life cycle control. We first revealed that EBV (LMP1) accelerates the secretion of the oncometabolite D-2HG, and serum D-2HG level is a potential diagnostic biomarker for NPC. EBV (LMP1)-driven metabolite changes disrupts the homeostasis of global DNA methylation and demethylation, which have a significantly inhibitory effect on active DNA demethylation and 5hmC content. We found that loss of 5hmC indicates a poor prognosis for NPC patients, and that 5hmC modification is a restriction factor of EBV reactivation. We confirmed a novel EBV reactivation inhibitor, α-KG, which inhibits the expression of EBV lytic genes with CpG-containing ZREs and the latent-lytic switch by enhancing 5hmC modification. Our results demonstrate a novel mechanism of which metabolite abnormality driven by EBV controls the viral lytic reactivation through epigenetic modification. This study presents a potential strategy for blocking EBV reactivation, and provides potential targets for the diagnosis and therapy of NPC.

The circadian clock gene, BMAL1, promotes radiosensitization in nasopharyngeal carcinoma by inhibiting the epithelial-to-mesenchymal transition via the TGF-ß1/Smads/Snail1 axis.

Acquired radio-resistance is thought to be one of the main causes of recurrent metastasis after failure of nasopharyngeal carcinoma (NPC) radiotherapy, which may be related to X-ray-induced epithelial-mesenchymal transition (EMT) activation. The circadian clock gene, BMAL1, has been shown to correlate with the sensitivity of NPCs to radiotherapy, but the specific mechanism has not been reported. NPC cells were irradiated by conventional fractionation to generate radiotherapy-resistant cells. NPC cells with BMAL1 gene stabilization/overexpression and interference were obtained by lentiviral transfection. Western blotting, colony formation analysis, cell counting kit-8 assays, wound-healing tests, Transwell assays, flow cytometry, the EDU method, nuclear plasma separation experiments, HE staining, immunohistochemical staining and TUNEL staining were performed to explore the influence and molecular mechanism of the circadian clock gene, BMAL1, on NPC-acquired radio-resistance and EMT through in vitro and in vivo experiments. The results indicated that there was a gradual downregulation of BMAL1 gene protein expression during the routine dose induction of radio-resistance in NPC cells. EMT activation was present in the radiation-resistant cell line 5-8FR, and was accompanied by the significant enhancement of proliferation, migration and invasion. The BMAL1 gene significantly increased the radiosensitivity of the radiation-resistant cell line 5-8FR and reversed the acquired radio-resistance of NPCs, which was accomplished by inhibiting the TGF-ß1/Smads/Snail1 axis-mediated EMT.

PICK1 inhibits the malignancy of nasopharyngeal carcinoma and serves as a novel prognostic marker.

Although many important advances have been made in the treatment of nasopharyngeal carcinoma (NPC) in recent years, local recurrence and distant metastasis remain the main factors affecting NPC prognosis. Biomarkers for predicting the prognosis of NPC need to be urgently identified. Here, we used whole-exon sequencing (WES) to determine whether PICK1 mutations are associated with the prognosis of NPC. Functionally, PICK1 inhibits the proliferation and metastasis of NPC cells both in vivo and in vitro. Mechanistically, PICK1 inhibited the expression of proteins related to the Wnt/ß-catenin signaling pathway. PICK1 restrained the nuclear accumulation of ß-catenin and accelerated the degradation of ß-catenin through the ubiquitin-proteasome pathway. The reduced PICK1 levels were significantly associated with poor patient prognosis. Hence, our study findings reveal the mechanism by which PICK1 inactivates the Wnt/ß-catenin signaling pathway, thereby inhibiting the progression of NPC. They support PICK1 as a potential tumor suppressor and prognostic marker for NPC.

CircCDYL2 bolsters radiotherapy resistance in nasopharyngeal carcinoma by promoting RAD51 translation initiation for enhanced homologous recombination repair.

BACKGROUND: Radiation therapy stands to be one of the primary approaches in the clinical treatment of malignant tumors. Nasopharyngeal Carcinoma, a malignancy predominantly treated with radiation therapy, provides an invaluable model for investigating the mechanisms underlying radiation therapy resistance in cancer. While some reports have suggested the involvement of circRNAs in modulating resistance to radiation therapy, the underpinning mechanisms remain unclear. METHODS: RT-qPCR and in situ hybridization were used to detect the expression level of circCDYL2 in nasopharyngeal carcinoma tissue samples. The effect of circCDYL2 on radiotherapy resistance in nasopharyngeal carcinoma was demonstrated by in vitro and in vivo functional experiments. The HR-GFP reporter assay determined that circCDYL2 affected homologous recombination repair. RNA pull down, RIP, western blotting, IF, and polysome profiling assays were used to verify that circCDYL2 promoted the translation of RAD51 by binding to EIF3D protein. RESULTS: We have identified circCDYL2 as highly expressed in nasopharyngeal carcinoma tissues, and it was closely associated with poor prognosis. In vitro and in vivo experiments demonstrate that circCDYL2 plays a pivotal role in promoting radiotherapy resistance in nasopharyngeal carcinoma. Our investigation unveils a specific mechanism by which circCDYL2, acting as a scaffold molecule, recruits eukaryotic translation initiation factor 3 subunit D protein (EIF3D) to the 5'-UTR of RAD51 mRNA, a crucial component of the DNA damage repair pathway to facilitate the initiation of RAD51 translation and enhance homologous recombination repair capability, and ultimately leads to radiotherapy resistance in nasopharyngeal carcinoma. CONCLUSIONS: These findings establish a novel role of the circCDYL2/EIF3D/RAD51 axis in nasopharyngeal carcinoma radiotherapy resistance. Our work not only sheds light on the underlying molecular mechanism but also highlights the potential of circCDYL2 as a therapeutic sensitization target and a promising prognostic molecular marker for nasopharyngeal carcinoma.

Lactoferrin mediates epithelial-mesenchymal transformation by regulating the PI3K/AKT/mTOR pathway to inhibit nasopharyngeal carcinoma metastasis.

Nasopharyngeal carcinoma (NPC) is a common malignant tumor of the head and neck. Epithelial-mesenchymal transition (EMT) is a major player in regulating NPC transfer. There is increasing evidence that lactotransferrin (LTF) is an important regulator of EMT conversion. However, the potential role and mechanisms of LTF in regulating NPC cell EMT remain unclear. In this study, quantitative real-time PCR (qRT‒PCR) and Western blotting were applied to measure the expression of LTF in NPC cells. Subsequently, the influences of LTF on the proliferation, migration and invasion of NPC cells were verified by functional acquisition experiments. Finally, Western blotting was used to analyze the effects of EMT-related proteins and phosphoinositol 3-kinase (PI3K)/Akt/mammalian rapamycin target (mTOR) signaling pathways. The data of this study indicate that LTF was underexpressed in human NPC cells, and upregulation of LTF could restrain NPC cell proliferation, invasion, migration and EMT transformation. Moreover, the effects of LTF on NPC cell metastasis and EMT are partly determined by the PI3K/AKT/mTOR pathway. This study suggests that LTF is a potential biomarker of NPC and that LTF-mediated EMT progression plays a tumor-suppressive role in the progression of NPC metastasis.

High expression of PPP1CC promotes NHEJ-mediated DNA repair leading to radioresistance and poor prognosis in nasopharyngeal carcinoma.

Protein phosphatase 1 catalytic subunit gamma (PPP1CC) promotes DNA repair and tumor development and progression, however, its underlying mechanisms remain unclear. This study investigated the molecular mechanism of PPP1CC's involvement in DNA repair and the potential clinical implications. High expression of PPP1CC was significantly correlated with radioresistance and poor prognosis in human nasopharyngeal carcinoma (NPC) patients. The mechanistic study revealed that PPP1CC bound to Ku70/Ku80 heterodimers and activated DNA-PKcs by promoting DNA-PK holoenzyme formation, which enhanced nonhomologous end junction (NHEJ) -mediated DNA repair and led to radioresistance. Importantly, BRCA1-BRCA2-containing complex subunit 3 (BRCC3) interacted with PPP1CC to enhance its stability by removing the K48-linked polyubiquitin chain at Lys234 to prevent PPP1CC degradation. Therefore, BRCC3 helped the overexpressed PPP1CC to maintain its high protein level, thereby sustaining the elevation of DNA repair capacity and radioresistance. Our study identified the molecular mechanism by which PPP1CC promotes NHEJ-mediated DNA repair and radioresistance, suggesting that the BRCC3-PPP1CC-Ku70 axis is a potential therapeutic target to improve the efficacy of radiotherapy.

Synergistic action of Hedyotis diffusa Willd and Andrographis paniculata in Nasopharyngeal Carcinoma: Downregulating AKT1 and upregulating VEGFA to curb tumorigenesis.

OBJECTIVE: Nasopharyngeal carcinoma (NPC) remains a challenging cancer to treat. This study investigates the molecular mechanisms of Hedyotis diffusa Willd (HDW) combined with Andrographis paniculata (AP) in treating NPC. METHODS: Key compounds and target genes in HDW and AP were analyzed using network pharmacology. Protein-protein interaction (PPI) networks were constructed with STRING and visualized using Cytoscape. MCODE identified critical clusters, while DAVID facilitated GO and KEGG analyses. In vivo and in vitro experiments evaluated HDW-AP effects on NPC, including tumor volume, weight, Ki-67 expression, cell apoptosis, migration, invasion, cell cycle distribution, and DNA damage. RESULTS: The database identified 495 NPC-related genes and 26 compounds in the HDW-AP pair, targeting 165 genes. Fifty-eight potential therapeutic genes were found, leading to 18 key targets. KEGG analysis revealed a significant impact on 78 pathways, especially cancer pathways. Both in vivo and in vitro tests showed HDW-AP inhibited NPC cell proliferation, migration, invasion, and induced apoptosis. Mechanistically, this was achieved through AKT1 downregulation and VEGFA upregulation. CONCLUSION: The combination of HDW and AP targets 16 key genes to impede the development of NPC, primarily by modulating AKT1 and VEGFA pathways.

PQR309, a dual PI3K/mTOR inhibitor, synergizes with gemcitabine by impairing the GSK-3ß and STAT3/HSP60 signaling pathways to treat nasopharyngeal carcinoma.

End-stage nasopharyngeal carcinoma (NPC) has unsatisfactory survival. The limited benefit of chemotherapy and the scarcity of targeted drugs are major challenges in NPC. New approaches to treat late-stage NPC are urgently required. In this study, we explored whether the dual PI3K/mTOR inhibitor, PQR309, exerted a favorable antineoplastic effect and sensitized the response to gemcitabine in NPC. We observed that PI3K expression was positive and elevated in 14 NPC cell lines compared with that in normal nasopharygeal cell lines. Patients with NPC with higher PI3K levels displayed poorer prognosis. We subsequently showed that PQR309 alone effectively decreased the viability, invasiveness, and migratory capability of NPC cells and neoplasm development in mice xenograft models, and dose-dependently induced apoptosis. More importantly, PQR309 remarkably strengthened the anti-NPC function of gemcitabine both in vivo and in vitro. Mechanistically, PQR309 sensitized NPC to gemcitabine by increasing caspase pathway-dependent apoptosis, blocking GSK-3ß and STAT3/HSP60 signaling, and ablating epithelial-mesenchyme transition. Thus, targeting PI3K/mTOR using PQR309 might represent a treatment option to promote the response to gemcitabine in NPC, and provides a theoretical foundation for the study of targeted drugs combined with chemotherapy for NPC.

m 6 A reader IGF2BP1 reduces the sensitivity of nasopharyngeal carcinoma cells to Taxol by upregulation of AKT2.

Taxol is widely used in the treatment of nasopharyngeal carcinoma (NPC); nevertheless, the acquired resistance of NPC to Taxol remains one of the major obstacles in clinical treatment. In this study, we aimed to investigate the role and mechanism of insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) in Taxol resistance of NPC. Taxol-resistant NPC cell lines were established by exposing to gradually increased concentration of Taxol. Relative mRNA and protein levels were tested using qRT-PCR and western blot, respectively. NPC cell viability and apoptosis were assessed by cell counting kit-8 and flow cytometry analysis, respectively. Cell migration and invasion capacities were measured using transwell assay. Interaction between IGF2BP1 and AKT2 was examined by RNA immunoprecipitation assay. The N6-methyladenosine level of AKT2 was tested using methylated RNA immunoprecipitation-qPCR. IGF2BP1 expression was enhanced in Taxol-resistant NPC cell lines. Knockdown of IGF2BP1 strikingly enhanced the sensitivity of NPC cells to Taxol and repressed the migration and invasion of NPC cells. Mechanistically, IGF2BP1 elevated the expression of AKT2 by increasing its mRNA stability. Furthermore, overexpression of AKT2 reversed the inhibitory roles of IGF2BP1 silence on Taxol resistance and metastasis. Our results indicated that IGF2BP1 knockdown enhanced the sensitivity of NPC cells to Taxol by decreasing the expression of AKT2, implying that IGF2BP1 might be promising candidate target for NPC treatment.