Therapeutic evaluation of palbociclib and its compatibility with other chemotherapies for primary and recurrent nasopharyngeal carcinoma

Development and Preclinical Assessment of a Palbociclib Nanostructured Lipid Carrier for Potential Breast Cancer Management

Breast cancer has the highest incidence rates among all cancers, which represent a global health concern. Effective chemotherapy for breast cancer must minimize adverse effects to improve patient outcomes. Palbociclib (PB), a CDK 4/6 inhibitor, restricts cell growth and suppresses DNA replication in the retinoblastoma tumor suppressor gene (RB). Despite its breakthrough status postapproval, PB is associated with severe side effects, including neutropenia, leukopenia, infections, and thrombocytopenia. The current study aims to develop and optimize a PB-loaded lipidic nanocarrier. The development method was solvent evaporation, and formulation optimization was performed using a central composite rotatable design. Characterization of the nanostructured lipid carrier (NLC) showed a particle size of 129.8 ± 7.6 nm with a PDI of 0.2694 ± 0.04 and a zeta potential of -29.8 ± 2.4 mV. Surface morphology was studied using transmission electron microscopy, which confirmed the particles' uniform and spherical shape. In vitro release studies in 0.1 N HCl and pH 6.8 phosphate buffer demonstrated cumulative drug releases of 91.23 ± 2.1% and 72.9 ± 2.0%, respectively. Intestinal permeation studies demonstrated a 3.76-fold increase in gut permeation with PB-NLC compared to that with PB-Sus. The lipolysis study indicated an enhanced drug availability at the site of absorption. Confocal studies revealed improved drug penetration depth in the intestine with PB-NLC compared to that with PB-Sus. In vivo pharmacokinetic studies demonstrated that incorporating PB into a lipidic nanocarrier (PB-NLC) significantly enhanced its bioavailability by approximately 5.9-fold (p < 0.05) compared to PB suspension. Additionally, acute toxicity studies in Wistar rats confirmed the safety of the developed NLC for oral administration in managing breast cancer. Therefore, the PB-loaded NLC shows significant promise for breast cancer treatment, providing improved drug delivery and minimized side effects.

Untangling the Role of MYC in Sarcomas and Its Potential as a Promising Therapeutic Target

MYC plays a pivotal role in the biology of various sarcoma subtypes, acting as a key regulator of tumor growth, proliferation, and metabolic reprogramming. This oncogene is frequently dysregulated across different sarcomas, where its expression is closely intertwined with the molecular features unique to each subtype. MYC interacts with critical pathways such as cell cycle regulation, apoptosis, and angiogenesis, amplifying tumor aggressiveness and resistance to standard therapies. Furthermore, MYC influences the tumor microenvironment by modulating cell-extracellular matrix interactions and immune evasion mechanisms, further complicating therapeutic management. Despite its well-established centrality in sarcoma pathogenesis, targeting MYC directly remains challenging due to its "undruggable" protein structure. However, emerging therapeutic strategies, including indirect MYC inhibition via epigenetic modulators, transcriptional machinery disruptors, and metabolic pathway inhibitors, offer new hope for sarcoma treatment. This review underscores the importance of understanding the intricate roles of MYC across sarcoma subtypes to guide the development of effective targeted therapies. Given MYC's central role in tumorigenesis and progression, innovative approaches aiming at MYC inhibition could transform the therapeutic landscape for sarcoma patients, providing a much-needed avenue to overcome therapeutic resistance and improve clinical outcomes.

CD25 downregulation by tumor exosomal microRNA-15a promotes interleukin-17-producing γδ-T-cells-mediated radioresistance in nasopharyngeal carcinoma

Interleukin (IL)-17-producing γδ-T cells (γδT-17) are a major source of IL-17 within the tumor microenvironment and have been shown to influence tumor development and therapy outcomes in various cancers. However, the role and presence of γδT-17 cells in nasopharyngeal carcinoma (NPC) remain poorly understood. It is also unclear how these cells might affect radiotherapy, the primary treatment for NPC patients. In this study, we discovered that NPC tumor tissues were rich in γδT-17 cells. Exosomes released from NPC cells (NPC-Exos) could direct γδ-T cells to differentiate into γδT-17 cells. These NPC-Exos-induced γδT-17 cells were found to enhance radioresistance in NPC, both in vitro and in vivo. Blocking IL-17 secreted by NPC-Exos-induced γδT-17 cells restored NPC cell sensitivity to radiation and elevated radiation-induced cell death. Mechanistic studies revealed that NPC-Exos not only increased the release of IL-17-promoting cytokines IL-1β, IL-6, and IL-23 from dendritic cells, but also suppressed CD25/IL-2 signaling in γδ-T cells, facilitating γδT-17 differentiation. The suppression of CD25/IL-2 signaling was driven by microRNA-15a (miR-15a) carried by NPC exosomes. Furthermore, miR-15a inhibitors were able to prevent γδT-17 induction by NPC-Exos. Our findings reveal a novel immunoregulatory role of NPC-Exos and offer potential strategies to combat NPC radioresistance.

High Ano1 expression as key driver of resistance to radiation and cisplatin in HPV-negative head and neck squamous cell carcinoma

Human papilloma virus-negative head and neck squamous cell carcinoma (HNSCC) frequently harbors 11q13 amplifications. Among the oncogenes at this locus, CCND1 and ANO1 are linked to poor prognosis; however, their individual roles in treatment resistance remain unclear. The impact of Cyclin D1 and Ano1 overexpression on survival was analyzed using the TCGA HNSCC dataset and a Charité cohort treated with cisplatin (CDDP)-based radiochemotherapy. High Ano1 expression was primarily associated with poor overall survival in both datasets. The effects of CCND1 and ANO1 knockdown (KD) on radio- and drug sensitivity, along with changes in global protein expression, cell viability, growth, and DNA repair, were studied in an 11q13-amplified HNSCC cell line model of primary cisplatin resistance. Unique pathway alterations- VEGF in CCND1 KD and the Rho GTPase cycle in ANO1 KD- were observed, along with shared changes like DNA damage and cell cycle dysregulation. Silencing CCND1 or ANO1 increased CDDP sensitivity, while only ANO1 silencing increased radiosensitivity. Copanlisib and afatinib were identified as promising candidates for combination therapy of 11q13-amplified HNSCC tumors. We demonstrated a predominant role for Ano1 in treatment resistance in Cyclin D1highAno1high HNSCC tumors and identified novel potential treatment combinations for this high-risk patient group.

Elucidating the Mechanisms of Acquired Palbociclib Resistance via Comprehensive Metabolomics Profiling

Palbociclib is a cyclin-dependent kinase 4/6 inhibitor and a commonly used antitumor drug. Many cancers are susceptible to palbociclib resistance, however, the underlying metabolism mechanism and extent of resistance to palbociclib are unknown. In this study, LC-MS metabolomics was used to investigate the metabolite changes of colorectal cancer SW620 cells that were resistant to palbociclib. The study indicated that there were 76 metabolite expression differences between SW620 cells with palbociclib resistance and the parental SW620 cells involving amino acids, glutathione, ABC transporters, and so on. MetaboAnalyst 6.0 metabolic pathway analysis showed that arginine synthesis, β-alanine metabolism, and purine metabolism were disrupted. These results may provide potential clues to the metabolism mechanism of drug resistance in cancer cells that are resistant to palbociclib. Our study has the potential to contribute to the study of anti-palbociclib resistance.

Investigation of the synergistic effect mechanism underlying sequential use of palbociclib and cisplatin through integral proteomic and glycoproteomic analysis

Chemoresistance largely hampers the clinical use of chemodrugs for cancer patients, combination or sequential drug treatment regimens have been designed to minimize chemotoxicity and resensitize chemoresistance. In this work, the cytotoxic effect of cisplatin was found to be enhanced by palbociclib pretreatment in HeLa cells. With the integration of liquid chromatography-mass spectrometry-based proteomic and N-glycoproteomic workflow, we found that palbociclib alone mainly enhanced the N-glycosylation alterations in HeLa cells, while cisplatin majorly increased the different expression proteins related to apoptosis pathways. As a result, the sequential use of two drugs induced a higher expression level of apoptosis proteins BAX and BAK. Those altered N-glycoproteins induced by palbociclib were implicated in pathways that were closely associated with cell membrane modification and drug sensitivity. Specifically, the top four frequently glycosylated proteins FOLR1, L1CAM, CD63, and LAMP1 were all associated with drug resistance or drug sensitivity. It is suspected that palbociclib-induced N-glycosylation on the membrane protein allowed the HeLa cell to become more vulnerable to cisplatin treatment. Our study provides new insights into the mechanisms underlying the sequential use of target drugs and chemotherapy drugs, meanwhile suggesting a high-efficiency approach that involves proteomic and N-glycoproteomic to facilitate drug discovery.

Progress in the clinical development of investigational systemic agents for recurrent and metastatic nasopharyngeal carcinoma

INTRODUCTION

Nasopharyngeal carcinoma (NPC) remains an endemic disease in certain parts of the world, with many patients presenting with advanced disease on diagnosis. Chemotherapy had remained the standard of care with minimal progress made until recent years. This review aims to provide an overview of recent significant breakthroughs and up-and-coming novel strategies in treating this deadly disease.

AREAS COVERED

This review focuses on the latest clinical development of promising investigational agents in the treatment of advanced NPC. These include anti-vascular agents, signaling pathways inhibitors and immunotherapy.

EXPERT OPINION

The addition of immune-checkpoint inhibitors (CPI) to platinum-based chemotherapy has undoubtedly changed the therapeutic landscape of R/M NPC in the first-line setting. This leaves much room for further research on the optimal treatment strategy in subsequent-line settings, likely including the addition of CPI to anti-vascular agents or novel CPI combinations, with or without chemotherapy as a backbone. Other potential approaches include optimal CPI maintenance therapy after first-line CPI-chemotherapy combination. Potential novel agents on the horizons are antibody-drug conjugates, bi-specific antibodies and signaling inhibitors, with several phase II/III studies currently underway.

Cell cycle machinery in oncology: A comprehensive review of therapeutic targets

The cell cycle is tightly regulated to ensure controlled cell proliferation. Dysregulation of the cell cycle machinery is a hallmark of cancer that leads to unchecked growth. This review comprehensively analyzes key molecular regulators of the cell cycle and how they contribute to carcinogenesis when mutated or overexpressed. It focuses on cyclins, cyclin-dependent kinases (CDKs), CDK inhibitors, checkpoint kinases, and mitotic regulators as therapeutic targets. Promising strategies include CDK4/6 inhibitors like palbociclib, ribociclib, and abemaciclib for breast cancer treatment. Other possible targets include the anaphase-promoting complex/cyclosome (APC/C), Skp2, p21, and aurora kinase inhibitors. However, challenges with resistance have limited clinical successes so far. Future efforts should focus on combinatorial therapies, next-generation inhibitors, and biomarkers for patient selection. Targeting the cell cycle holds promise but further optimization is necessary to fully exploit it as an anti-cancer strategy across diverse malignancies.

Combination Therapy as a Promising Way to Fight Oral Cancer

Oral cancer is a highly aggressive tumor with invasive properties that can lead to metastasis and high mortality rates. Conventional treatment strategies, such as surgery, chemotherapy, and radiation therapy, alone or in combination, are associated with significant side effects. Currently, combination therapy has become the standard practice for the treatment of locally advanced oral cancer, emerging as an effective approach in improving outcomes. In this review, we present an in-depth analysis of the current advancements in combination therapies for oral cancer. The review explores the current therapeutic options and highlights the limitations of monotherapy approaches. It then focuses on combinatorial approaches that target microtubules, as well as various signaling pathway components implicated in oral cancer progression, namely, DNA repair players, the epidermal growth factor receptor, cyclin-dependent kinases, epigenetic readers, and immune checkpoint proteins. The review discusses the rationale behind combining different agents and examines the preclinical and clinical evidence supporting the effectiveness of these combinations, emphasizing their ability to enhance treatment response and overcome drug resistance. Challenges and limitations associated with combination therapy are discussed, including potential toxicity and the need for personalized treatment approaches. A future perspective is also provided to highlight the existing challenges and possible resolutions toward the clinical translation of current oral cancer therapies.

Inhibition of the MNK1/2-eIF4E Axis Augments Palbociclib-Mediated Antitumor Activity in Melanoma and Breast Cancer

Aberrant cell-cycle progression is characteristic of melanoma, and CDK4/6 inhibitors, such as palbociclib, are currently being tested for efficacy in this disease. Despite the promising nature of CDK4/6 inhibitors, their use as single agents in melanoma has shown limited clinical benefit. Herein, we discovered that treatment of tumor cells with palbociclib induces the phosphorylation of the mRNA translation initiation factor eIF4E. When phosphorylated, eIF4E specifically engenders the translation of mRNAs that code for proteins involved in cell survival. We hypothesized that cancer cells treated with palbociclib use upregulated phosphorylated eIF4E (phospho-eIF4E) to escape the antitumor benefits of this drug. Indeed, we found that pharmacologic or genetic disruption of MNK1/2 activity, the only known kinases for eIF4E, enhanced the ability of palbociclib to decrease clonogenic outgrowth. Moreover, a quantitative proteomics analysis of melanoma cells treated with combined MNK1/2 and CDK4/6 inhibitors showed downregulation of proteins with critical roles in cell-cycle progression and mitosis, including AURKB, TPX2, and survivin. We also observed that palbociclib-resistant breast cancer cells have higher basal levels of phospho-eIF4E, and that treatment with MNK1/2 inhibitors sensitized these palbociclib-resistant cells to CDK4/6 inhibition. In vivo we demonstrate that the combination of MNK1/2 and CDK4/6 inhibition significantly increases the overall survival of mice compared with either monotherapy. Overall, our data support MNK1/2 inhibitors as promising drugs to potentiate the antineoplastic effects of palbociclib and overcome therapy-resistant disease.

Investigation on acquired palbociclib resistance by LC-MS based multi-omics analysis

Palbociclib is a specific CDK4/6 inhibitor that has been widely applied in multiple types of tumors. Different from cytotoxic drugs, the anticancer mechanism of palbociclib mainly depends on cell cycle inhibition. Therefore, the resistance mechanism is different. For clinical cancer patients, drug resistance is inevitable for almost all cancer therapies including palbociclib. We have trained palbociclib resistant cells in vitro to simulate the clinical situation and applied LC-MS multi-omics analysis methods including proteomic, metabolomic, and glycoproteomic techniques, to deeply understand the underly mechanism behind the resistance. As a result of proteomic analysis, the resistant cells were found to rely on altered metabolic pathways to keep proliferation. Metabolic processes related to carbohydrates, lipids, DNA, cellular proteins, glucose, and amino acids were observed to be upregulated. Most dramatically, the protein expressions of COX-1 and NDUFB8 have been detected to be significantly overexpressed by proteomic analysis. When a COX-1 inhibitor was hired to combine with palbociclib, a synergistic effect could be obtained, suggesting the altered COX-1 involved metabolic pathway is an important reason for the acquired palbociclib resistance. The KEGG pathway of N-glycan biosynthesis was identified through metabolomics analysis. N-glycoproteomic analysis was therefore included and the global glycosylation was found to be elevated in the palbociclib-resistant cells. Moreover, integration analysis of glycoproteomic data allowed us to detect a lot more proteins that have been glycosylated with low abundances, these proteins were considered to be overwhelmed by those highly abundant proteins during regular proteomic LC-MS detection. These low-abundant proteins are mainly involved in the cellular biology processes of cell migration, the regulation of chemotaxis, as well as the glycoprotein metabolic process which offered us great more details on the roles played by N-glycosylation in drug resistance. Our result also verified that N-glycosylation inhibitors could enhance the cell growth inhibition of palbociclib in resistant cells. The high efficiency of the integrated multi-omics analysis workflow in discovering drug resistance mechanisms paves a new way for drug development. With a clear understanding of the resistance mechanism, new drug targets and drug combinations could be designed to resensitize the resistant tumors.

Targeted therapy for head and neck cancer: signaling pathways and clinical studies

Head and neck cancer (HNC) is malignant, genetically complex and difficult to treat and is the sixth most frequent cancer, with tobacco, alcohol and human papillomavirus being major risk factors. Based on epigenetic data, HNC is remarkably heterogeneous, and treatment remains challenging. There is a lack of significant improvement in survival and quality of life in patients with HNC. Over half of HNC patients experience locoregional recurrence or distal metastasis despite the current multiple traditional therapeutic strategies and immunotherapy. In addition, resistance to chemotherapy, radiotherapy and some targeted therapies is common. Therefore, it is urgent to explore more effective and tolerable targeted therapies to improve the clinical outcomes of HNC patients. Recent targeted therapy studies have focused on identifying promising biomarkers and developing more effective targeted therapies. A well understanding of the pathogenesis of HNC contributes to learning more about its inner association, which provides novel insight into the development of small molecule inhibitors. In this review, we summarized the vital signaling pathways and discussed the current potential therapeutic targets against critical molecules in HNC, as well as presenting preclinical animal models and ongoing or completed clinical studies about targeted therapy, which may contribute to a more favorable prognosis of HNC. Targeted therapy in combination with other therapies and its limitations were also discussed.

Proteomics reveals that cell density could affect the efficacy of drug treatment

In vitro cell biology study plays a fundamental role in biological and drug development research, but the repeatability and accuracy of cell studies remain to be low. Various uncertainties during the cell culture process could introduce bias into drug research. In this study, we evaluate the potential effects and underlying mechanisms induced by cell number differences in the cell seeding process. Normally, drug experiments are initiated 24 h after cell seeding, and the difference in the cell number at the time of inoculation leads to the difference in cell confluence (cell density) when drug research is conducted. While cell confluence is closely related to intercellular communication, surface protein interaction, cell autocrine as well as paracrine protein expression of cells, it might have a potential impact on the effect of biological studies such as drug treatment. This study used proteomics technology to comprehensively explore the different protein expression patterns between cells with different confluences. Due to the high sensitivity and high throughput of liquid chromatography-mass spectrometry (LC-MS/MS) detection, it was hired to evaluate the protein expression differences of Hep3B cells with 3 different confluences (30%, 50%, and 70%). The differential expressed proteins were analyzed by the Reactome pathway and the Gene Ontology (GO) pathway. Significant differences were identified across three confluences in terms of the number of proteins identified, the protein expression pattern, and the expression level of certain KEGG pathways. We found that those proteins involved in the cell cycle pathway were differently expressed: the higher the cell confluence, the higher these proteins expressed. A cell cycle inhibitor palbociclib was selected to further verify this observation. Palbociclib in the same dose was applied to cells with different confluence, the results indicated that the growth inhibition effect of palbociclib increases along with the increasing trend of cell cycle protein expression. The result indicated that cell density did influence the effect of drug treatment. Furthermore, three other drugs, cisplatin, paclitaxel, and imatinib, were used to treat the three liver cancer cell lines Hep3B, SUN387, and MHCC97, and a similar observation was obtained that drug effect would be different when the cell confluences were different. Therefore, selecting an appropriate number of cells for plating is vitally important at the beginning of a drug study.

In vivo efficacy assessment of the CDK4/6 inhibitor palbociclib and the PLK1 inhibitor volasertib in human chordoma xenografts

Background

Management of advanced chordomas remains delicate considering their insensitivity to chemotherapy. Homozygous deletion of the regulatory gene CDKN2A has been described as the most frequent genetic alteration in chordomas and may be considered as a potential theranostic marker. Here, we evaluated the tumor efficacy of the CDK4/6 inhibitor palbociclib, as well as the PLK1 inhibitor volasertib, in three chordoma patient-derived xenograft (PDX) models to validate and identify novel therapeutic approaches.

Methods

From our chordoma xenograft panel, we selected three models, two of them harboring a homozygous deletion of CDKN2A/2B genes, and the last one a PBRM1 pathogenic variant (as control). For each model, we tested the palbociclib and volasertib drugs with pharmacodynamic studies together with RT-PCR and RNAseq analyses.

Results

For palbociclib, we observed a significant tumor response for one of two models harboring the deletion of CDKN2A/2B (p = 0.02), and no significant tumor response in the PBRM1-mutated PDX; for volasertib, we did not observe any response in the three tested models. RT-PCR and RNAseq analyses showed a correlation between cell cycle markers and responses to palbociclib; finally, RNAseq analyses showed a natural enrichment of the oxidative phosphorylation genes (OxPhos) in the palbociclib-resistant PDX (p = 0.02).

Conclusion

CDK4/6 inhibition appears as a promising strategy to manage advanced chordomas harboring a loss of CDKN2A/2B. However, further preclinical studies are strongly requested to confirm it and to understand acquired or de novo resistance to palbociclib, in the peculiar view of a targeting of the oxidative phosphorylation genes.

Treatment of Recurrent Nasopharyngeal Carcinoma: A Sequential Challenge

Recurrent nasopharyngeal carcinoma (NPC), which occurs in 10-20% of patients with primary NPC after the initial treatment modality of intensity-modulated radiation therapy (IMRT), is one of the major causes of death among NPC patients. Patients with recurrent disease without distant metastases still have a chance to be saved, but re-treatment often carries more serious toxicities or higher risks. For this group of patients, both otolaryngologists and oncologists are committed to developing more appropriate treatment regimens that can prolong patient survival and improve survival therapy. Currently, there are no international guidelines for the treatment of patients with recurrent NPC. In this article, we summarize past publications on clinical research and mechanistic studies related to recurrent NPC, combined with the experience and lessons learned by our institutional multidisciplinary team in the treatment of recurrent NPC. We propose an objective protocol for the treatment of recurrent NPC.

HOTAIR mediates cisplatin resistance in nasopharyngeal carcinoma by regulating miR-106a-5p/SOX4 axis

This study explored the function and mechanisms of HOX transcript antisense RNA (HOTAIR) in the drug resistance of nasopharyngeal carcinoma (NPC). Quantitative PCR, Western blotting, MTT assay, flow cytometry, Transwell assay, and luciferase assay were performed. HOTAIR expression levels were upregulated in cisplatin (DDP)-resistant NPC tissues and cells. Knockdown of HOTAIR in DDP-resistant NPC cells increased cell sensitivity of DDP, as well as decreased cell viability, expression of chemoresistance-related proteins, migration and invasion, increased cell apoptosis. In addition, downregulation of microRNA 106a-5p (miR-106a-5p) expression and upregulation of SRY-box transcription factor 4 (SOX4) expression were observed in DDP-resistant NPC tissues and cells. MiR-106a-5p targets HOTAIR and SOX4; thus, silencing of HOTAIR significantly increased miR-106a-5p expression. The overexpression of miR-106a-5p significantly reversed the increase in SOX4 expression induced by HOTAIR lentivirus (Lv-HOTAIR). Knockdown of SOX4 reduced the drug resistance of DDP caused by the silencing of miR-106a-5p expression. In summary, HOTAIR enhanced DDP resistance in NPC cells by regulating the miR-106a-5p/SOX4 axis.

Exosomes derived from γδ-T cells synergize with radiotherapy and preserve antitumor activities against nasopharyngeal carcinoma in immunosuppressive microenvironment

Background

Radiotherapy is the first-line treatment for patients nasopharyngeal carcinoma (NPC), but its therapeutic efficacy is poor in some patients due to radioresistance. Adoptive T cell-based immunotherapy has also shown promise to control NPC; however, its antitumor efficacy may be attenuated by an immunosuppressive tumor microenvironment. Exosomes derived from γδ-T cells (γδ-T-Exos) have potent antitumor potentials. However, it remains unknown whether γδ-T-Exos have synergistic effect with radiotherapy and preserve their antitumor activities against NPC in an immunosuppressive tumor microenvironment.

Methods

γδ-T-Exos were stained with fluorescent membrane dye, and their interactions with NPC were determined both in vitro and in vivo. NPC cell deaths were detected after treatment with γδ-T-Exos and/or irradiation. Moreover, effects of γδ-T-Exos on radioresistant cancer stem-like cells (CSCs) were determined. The therapeutic efficacy of combination therapy using γδ-T-Exos and irradiation on NPC tumor progression was also monitored in vivo. Finally, the tumor-killing and T cell-promoting activities of γδ-T-Exos were determined under the culture in immunosuppressive NPC supernatant.

Results

γδ-T-Exos effectively interacted with NPC tumor cells in vitro and in vivo. γδ-T-Exos not only killed NPC cells in vitro, which was mainly mediated by Fas/Fas ligand (FasL) and death receptor 5 (DR5)/tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) pathways, but also controlled NPC tumor growth and prolonged tumor-bearing mice survival in vivo. Furthermore, γδ-T-Exos selectively targeted the radioresistant CD44^+/high CSCs and induced profound cell apoptosis. The combination of γδ-T-Exos with radiotherapy overcame the radioresistance of CD44^+/high NPC cells and significantly improved its therapeutic efficacy against NPC in vitro and in vivo. In addition, γδ-T-Exos promoted T-cell migration into NPC tumors by upregulating CCR5 on T cells that were chemoattracted by CCR5 ligands in the NPC tumor microenvironment. Although NPC tumor cells secreted abundant tumor growth factor beta to suppress T-cell responses, γδ-T-Exos preserved their direct antitumor activities and overcame the immunosuppressive NPC microenvironment to amplify T-cell antitumor immunity.

Conclusions

γδ-T-Exos synergized with radiotherapy to control NPC by overcoming the radioresistance of NPC CSCs. Moreover, γδ-T-Exos preserved their tumor-killing and T cell-promoting activities in the immunosuppressive NPC microenvironment. This study provides a proof of concept for a novel and potent strategy by combining γδ-T-Exos with radiotherapy in the control of NPC.

Longitudinal evaluation of five nasopharyngeal carcinoma animal models on the microPET/MR platform

PURPOSE

We longitudinally evaluated the tumour growth and metabolic activity of three nasopharyngeal carcinoma (NPC) cell line models (C666-1, C17 and NPC43) and two xenograft models (Xeno76 and Xeno23) using a micropositron emission tomography and magnetic resonance (microPET/MR). With a better understanding of the interplay between tumour growth and metabolic characteristics of these NPC models, we aim to provide insights for the selection of appropriate NPC cell line/xenograft models to assist novel drug discovery and evaluation.

METHODS

Mice were imaged by ¹⁸F-deoxyglucose ([¹⁸F]FDG) microPET/MR twice a week for consecutive 3-7 weeks. [¹⁸F]FDG uptake was quantified by standardized uptake value (SUV) and presented as SUVmean tumour-to-liver ratio (SUVRmean). Longitudinal tumour growth patterns and metabolic patterns were recorded. SUVRmean and histological characteristics were compared across the five NPC models. Cisplatin was administrated to one selected optimal tumour model, C17, to evaluate our imaging platform.

RESULTS

We found variable tumour growth and metabolic patterns across different NPC tumour types. C17 has an optimal growth rate and higher tumour metabolic activity compared with C666-1. C666-1 has a fast growth rate but is low in SUVRmean at endpoint due to necrosis as confirmed by H&E. NPC43 and Xeno76 have relatively slow growth rates and are low in SUVRmean, due to severe necrosis. Xeno23 has the slowest growth rate, and a relative high SUVRmean. Cisplatin showed the expected therapeutic effect in the C17 model in marked reduction of tumour size and metabolism.

CONCLUSION

Our study establishes an imaging platform that characterizes the growth and metabolic patterns of different NPC models, and the platform is well able to demonstrate drug treatment outcome supporting its use in novel drug discovery and evaluation for NPC.

Combination of Epithelial Growth Factor Receptor Blockers and CDK4/6 Inhibitor for Nasopharyngeal Carcinoma Treatment

Simple Summary

Our findings indicated that the EGF-EGFR pathway was highly activated in very young patients with recurrent or metastatic NPC. High EGFR expression in patients with metastatic NPC resulted in poor clinical outcomes. To examine whether the EGFR pathway serves as a therapeutic target for NPC, NPC patient-derived xenograft (PDX) and NPC cell lines were treated with EGFR inhibitors (EGFRi) and a cell cycle blocker. Either EGFRi or cell cycle blocker treatment alone could reduce NPC cell growth and PDX tumor growth. Furthermore, combination treatment exerted an additive suppression effect on PDX tumor growth. This study provides promising evidence that EGFRi used in combination with a cell cycle blocker may be used to treat patients with NPC.

Abstract

Background: Nasopharyngeal carcinoma (NPC) involves host genetics, environmental and viral factors. In clinical observations, patients of young and old ages were found to have higher recurrence and metastatic rates. Methods: Cytokine array was employed to screen druggable target(s). The candidate target(s) were confirmed through patient-derived xenografts (PDXs) and a new EBV-positive cell line, NPC-B13. Results: Overexpression of epithelial growth factor (EGF) and EGF receptor (EGFR) was detected in young patients than in older patients. The growth of NPC PDX tumors and cell lines was inhibited by EGFR inhibitors (EGFRi) cetuximab and afatinib when used separately or in combination with the cell cycle blocker palbociclib. Western blot analysis of these drug-treated PDXs demonstrated that the blockade of the EGF signaling pathway was associated with a decrease in the p-EGFR level and reduction in PDX tumor size. RNA sequencing results of PDX tumors elucidated that cell cycle-related pathways were suppressed in response to drug treatments. High EGFR expression (IHC score ≥ grade 3) was correlated with poor survival in metastatic patients (p = 0.008). Conclusions: Our results provide encouraging preliminary data related to the combination treatment of EGFRi and palbociclib in patients with NPC.