GABA regulates the proliferation and apoptosis of head and neck squamous cell carcinoma cells by promoting the expression of CCND2 and BCL2L1.

Gamma-aminobutyric acid (GABA) is a multifunctional molecule that is widely present in the nervous system and nonneuronal tissues. It plays pivotal roles in neurotransmission, regulation of secretion, cell differentiation, proliferation, and tumorigenesis. However, the exact mechanisms of GABA in head and neck squamous cell carcinomas (HNSCCs) are unknown. We took advantage of RNA sequencing in this work and uncovered the potential gene expression profiles of the GABA-treated HNSCC cell line HN4-2. We found that the expression of CCND2 and BCL2L1 was significantly upregulated. Furthermore, GABA treatment inhibited the cell apoptosis induced by cisplatin and regulated the cell cycle after treatment with cisplatin in HN4-2 cells. Moreover, we also found that GABA could upregulate the expression of CCND2 and BCL2L1 after treatment with cisplatin. Our results not only reveal the potential pro-tumorigenic effect of GABA on HNSCCs but also provide a novel therapeutic target for HNSCC treatment.

Enhancing prognostic accuracy in head and neck squamous cell carcinoma chemotherapy via a lipid metabolism-related clustered polygenic model.

OBJECTIVE: Systemic chemotherapy is the first-line therapeutic option for head and neck squamous cell carcinoma (HNSCC), but it often fails. This study aimed to develop an effective prognostic model for evaluating the therapeutic effects of systemic chemotherapy. METHODS: This study utilized CRISPR/cas9 whole gene loss-of-function library screening and data from The Cancer Genome Atlas (TCGA) HNSCC patients who have undergone systemic therapy to examine differentially expressed genes (DEGs). A lipid metabolism-related clustered polygenic model called the lipid metabolism related score (LMRS) model was established based on the identified functionally enriched DEGs. The prediction efficiency of the model for survival outcome, chemotherapy, and immunotherapy response was evaluated using HNSCC datasets, the GEO database and clinical samples. RESULTS: Screening results from the study demonstrated that genes those were differentially expressed were highly associated with lipid metabolism-related pathways, and patients receiving systemic therapy had significantly different prognoses based on lipid metabolism gene characteristics. The LMRS model, consisting of eight lipid metabolism-related genes, outperformed each lipid metabolism gene-based model in predicting outcome and drug response. Further validation of the LMRS model in HNSCCs confirmed its prognostic value. CONCLUSION: In conclusion, the LMRS polygenic prognostic model is helpful to assess outcome and drug response for HNSCCs and could assist in the timely selection of the appropriate treatment for HNSCC patients. This study provides important insights for improving systemic chemotherapy and enhancing patient outcomes.

Sex-specific gene expression patterns in head and neck squamous cell carcinomas.

Objective: The head and neck squamous cell carcinomas (HNSCCs) have higher incidence rates in men, but the reasons are still obscure. This study aimed to investigate the sex-specific gene expression patterns and predict the regulatory mechanisms. Design: Data including clinical, survival, RNA-seq, miRNA, and methylation information were derived from The Cancer Genome Atlas (TCGA). A total of 131 paired male and female cases were included based on propensity score matching. We concentrated on the prognostic values of the sex-specific pathways enriched by differentially expressed genes (DEGs) and predicted the potential regulatory mechanisms from immune cell infiltration, ceRNA regulatory network, methylation, and differential coexpression analysis. Results: Compared with females, males exhibited a lower activity of immune-related functions and higher activities of mitochondrial and ubiquitination functions. The pathway activities were associated with the prognosis of males but less relevant to females. We extracted eight pathways with sex-biased survival patterns, of which five were about down-regulated immune functions, and three were up-regulated pathways (GTP biosynthetic, DNA polymerase, and spliceosomal complex assembly). The five immune pathways were moderately or strongly correlated with the proportion of macrophages. We identified six over-expressed lncRNAs that might be involved in the regulation of the three up-regulated pathways. These lncRNAs exhibited a lower methylation density in males, which might account for their over-expression. Conclusions: For HNSCCs, males were characterized by immunosuppression. It was a sign of unfavorable prognosis and might be associated the proportion of macrophages. LncRNAs and methylation might be involved in the regulation of these pathways.

MAPKAPK2-centric transcriptome profiling reveals its major role in governing molecular crosstalk of IGFBP2, MUC4, and PRKAR2B during HNSCC pathogenesis.

Transcriptome analysis of head and neck squamous cell carcinoma (HNSCC) has been pivotal to comprehending the convoluted biology of HNSCC tumors. MAPKAPK2 or MK2 is a critical modulator of the mRNA turnover of crucial genes involved in HNSCC progression. However, MK2-centric transcriptome profiles of tumors are not well known. This study delves into HNSCC progression with MK2 at the nexus to delineate the biological relevance and intricate crosstalk of MK2 in the tumor milieu. We performed next-generation sequencing-based transcriptome profiling of HNSCC cells and xenograft tumors to ascertain mRNA expression profiles in MK2-wild type and MK2-knockdown conditions. The findings were validated using gene expression assays, immunohistochemistry, and transcript turnover studies. Here, we identified a pool of crucial MK2-regulated candidate genes by annotation and differential gene expression analyses. Regulatory network and pathway enrichment revealed their significance and involvement in the HNSCC pathogenesis. Additionally, 3'-UTR-based filtering recognized important MK2-regulated downstream target genes and validated them by nCounter gene expression assays. Finally, immunohistochemistry and transcript stability studies revealed the putative role of MK2 in regulating the transcript turnover of IGFBP2, MUC4, and PRKAR2B in HNSCC. Conclusively, MK2-regulated candidate genes were identified in this study, and their plausible involvement in HNSCC pathogenesis was elucidated. These genes possess investigative values as targets for diagnosis and therapeutic interventions for HNSCC.

Perspectives of lipid metabolism reprogramming in head and neck squamous cell carcinoma: An overview.

Recent studies showed that lipid metabolism reprogramming contributes to tumorigenicity and malignancy by interfering energy production, membrane formation, and signal transduction in cancers. HNSCCs are highly reliant on aerobic glycolysis and glutamine metabolism. However, the mechanisms underlying lipid metabolism reprogramming in HNSCCs remains obscure. The present review summarizes and discusses the "vital" cellular signaling roles of the lipid metabolism reprogramming in HNSCCs. We also address the differences between HNSCCs regions caused by anatomical heterogeneity. We enumerate these recent findings into our current understanding of lipid metabolism reprogramming in HNSCCs and introduce the new and exciting therapeutic implications of targeting the lipid metabolism.

Paeoniflorigenone regulates apoptosis, autophagy, and necroptosis to induce anti-cancer bioactivities in human head and neck squamous cell carcinomas.

ETHNOPHARMACOLOGICAL RELEVANCE: Paonia suffruticosa Andr. belonging to the family Paeoniaceae and has been used as a medicinal plant in Asian countries including China, Korea, and Japan. The roots of P. suffruticosa has been used in traditional medicine in various diseases including cancer and cardiovascular, female genital, and inflammatory diseases. AIM OF THE STUDY: Head and neck squamous cell carcinomas (HNSCCs) pathologically account for 90% of all head and neck cancers. However, effective targeted therapies for HNSCCs are insufficient and the prognosis is very poor, especially in patients with metastatic HNSCCs. To overcome the current limitations of available therapies for HNSCCs, pathological approaches using natural compounds are attracting attention. Our study aimed to demonstrate the anti-cancer effects of paeoniflorigenone (Paeo, 98.9% purity) isolated from the root bark of P. suffruticosa. MATERIALS AND METHODS: Our scientific methodology was performed as follows: cytotoxicity, morphological changes, and apototic DNA fragmentation were analyzed using MTT, light microscopy, and TUNEL assays. Protein expression, apoptosis, necroptosis, and autophagy were analyzed using Western blot and immunofluorescence assays. Cell migration and invasion were analyzed using wound healing and Boyden chamber assays. RESULTS: We demonstrated that Paeo significantly reduced cell proliferation and cell division, leading to caspase-dependent apoptotic cell death in human YD-10B HNSCC cells. This result was associated with PI3K/AKT/mTOR/p70S6K signaling in these cells. In addition, we investigated other programmed cell death mechanisms associated with apoptosis and found that Paeo inhibited necroptosis via dephosphorylation of key necroptotic proteins (RIP and MLKL), whereas Paeo induced autophagy via increased LC3I/II expression and autophagosome formation in human YD-10B HNSCC cells. The anti-metastatic effects of Paeo significantly suppressed cell migration and invasion in human YD-10B HNSCC cells. CONCLUSION: Overall, our results demonstrated that the bioactive compound, Paeo, exhibited anti-cancer bioactivities in human YD-10B HNSCC cells, suggesting that Paeo may be an attractive pathological approach for patients with human HNSCCs.

In vivo monitoring of the therapeutic efficacy of a CXCR1/2 inhibitor with 18F-FDG PET/CT imaging in experimental head and neck carcinoma: A feasibility study.

The chemokine receptors CXCR1/2 play a key role in the aggressiveness of several types of cancers including head and neck squamous cell carcinomas (HNSCCs). In HNSCCs, CXCR1/2 signaling promotes cell proliferation and angiogenesis leading to tumor growth and metastasis. The competitive inhibitor of CXCR1/2, C29, inhibits the growth of experimental HNSCCs in mice. However, a non-invasive tool to monitor treatment response is essential to implement the use of C29 in clinical practices. 18F-FDG PET/CT is a gold-standard tool for the staging and the post-therapy follow-up of HNSCCs patients. Our study aimed to perform the first in vivo monitoring of C29 efficacy by non-invasive 18F-FDG PET/CT imaging. Mice bearing experimental HNSCCs (CAL33) were injected with 18F-FDG (T0) and thereafter treated (n = 7 mice, 9 tumors, 50 mg/kg by gavage) or not (n = 7 mice, 10 tumors) with C29 for 4 consecutive days. Final 18F-FDG-tumor uptake was determined at day 4 (TF). The average relative change (TF-T0) in 18F-FDG tumor uptake was +25.85 ± 10.93 % in the control group vs -5.72 ± 10.07 % in the C29-treated group (p < 0.01). These results were consistent with the decrease of the tumor burden and with the decrease of tumor proliferating Ki67+ cells. These results paved the way for the use of 18F-FDG to monitor tumor response following C29 treatment.

Ruthenium arene complexes in the treatment of 3D models of head and neck squamous cell carcinomas.

Current chemotherapy for head and neck squamous cell carcinomas (HNSCCs) are based on cisplatin, which is usually associated to severe side effects. In general, the exploration for metal-based alternatives to cisplatin has resulted in the development of a series of ruthenium complexes that are able to produce a safe therapeutic action against some neoplasms, among which are lung and ovarian cancers. Here, we evaluate the efficacy of well defined, easily available and robust ruthenium(II) η6-arene compounds on 3D models of HNSCCs with or without human papillomavirus (HPV) infection and compare their effects to the state-of-the-art RAPTA-C, a promising ruthenium compound with known anti-cancer activity. One of the compounds induces a significant therapeutic action especially on HPV negative carcinoma. Besides viability and repopulation evaluations, we performed quantitative analysis of the internalized Ru compounds to further validate our findings and elucidate the possible mechanisms of action. These results show that Ru arene compounds represent a promising alternative for the treatment of HNSCCs and pave the way for the composition of innovative (co)therapies.

Prognostic value of immune-related genes and immune cell infiltration analysis in the tumor microenvironment of head and neck squamous cell carcinoma.

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) is one of the few malignant tumors that respond well to immunotherapy. We aimed to investigate the immune-related genes and immune cell infiltration of HNSCC and construct a predictive model for its prognosis. METHODS: We calculated the stromal/immune scores of patients with HNSCC from The Cancer Genome Atlas using the Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data algorithm and investigated the relationship between the scores and patients' prognosis. Three machine learning algorithms (LASSO, Random Forest, and Rbsurv) were performed to screen key immune-related genes and constructed a predictive model. The immune cell infiltrating was calculated by the Tumor Immune Estimation Resource algorithm. RESULTS: The stromal and immune scores significantly correlated with prognosis. A 6-gene signature was selected and displayed a robust predictive effect. The expressions of key genes were associated with immune infiltrating. GSE65858 validated the results. CONCLUSION: Our study comprehensively analyzed the tumor microenvironment of HNSCC and constructed a robust predictive model, providing a basis for further investigation of therapy.

Survival rates of head and neck cancers in Ghana: a retrospective study at the Komfo Anokye Teaching Hospital.

OBJECTIVE: Data was collected to evaluate the survival rates of head and neck (conjunctiva, oropharyngeal and non-oropharyngeal) squamous cell carcinomas in Ghana. DATA DESCRIPTION: We provided data on a retrospective review of 8 years (January 2004 to December 2009) survival rate of head and neck squamous cell carcinomas (HNSCCs) at the Komfo Anokye Teaching Hospital in Ghana. The data consist of patient demographic data and clinicopathological findings which includes tumour site, tumour stage and histological grades of the patients. Clinical outcome measurement was death through to January 2013 on record and confirmed from the hospitals birth and death registry department. More than 85% of death cases were confirmed by gender, age, and folder identification numbers from the birth and death registry.

Associations between expression levels of nine core nucleotide excision repair genes in lymphocytes and risk of head and neck squamous cell carcinomas in a Chinese population.

BACKGROUND: Head and neck squamous cell carcinomas (HNSCCs) are one of the most common cancers in the world, and nucleotide excision repair (NER) is involved in HNSCCs susceptibility. We investigated whether mRNA expression levels of nine core NER genes were associated with risk of HNSCCs in a Chinese population. METHODS: In this study of 251 HNSCC patients and 232 healthy controls, we quantified NER gene mRNA expression levels in cultured peripheral lymphocytes using a quantitative real-time PCR. RESULTS: Compared with the controls, HNSCC patients had statistically significantly lower expression levels of XPA and XPB (P = 0.029 and 0.001, respectively). After dividing the subjects by the controls' median values of expression levels, we found a dose-dependent association between an increased risk of HNSCCs and low expression levels of XPB (adjusted OR 1.56 and 95% CI 1.07-2.28; Ptrend = 0.001). We also identified a significant multiplicative interaction between smoking status as well as alcohol status and mRNA expression levels of XPB (P = 0.014 and 0.042, respectively). Finally, after integrating demographic variables, we found the addition of smoking status and XPB expression levels to the model significantly improved the sensitivity of the expanded model on HNSCC risk. CONCLUSION: Reduced mRNA expression levels of XPB were associated with an increased risk of HNSCCs in a Chinese population.

Prevalence of Human Papilloma Virus Sub Genotypes following Head and Neck Squamous Cell Carcinomas in Asian Continent, A Systematic Review Article.

OBJECTIVES: In current era of blue brain intelligence and technology access at ease, standardization of disease etiology demands extensive research to drop-down human papilloma virus associated head and neck squamous cell carcinomas impact at large. Present retrospection aims to estimate comparative association of human papilloma virus sub-genotypes in head and neck squamous cell carcinomas, critical analysis of existing research gap, treatment progress, co-infection, gender association, national status and challenges following Human papilloma virus led head and neck squamous cell carcinomas among world largest continent. BACKGROUND: Head and neck squamous cell carcinomas are not just like malignancies of uterine cervix, lymph nodes and breast cancers. Human papilloma virus led head and neck squamous cell carcinomas treatment directly impact Central nervous system in humans. Intriguingly, human papilloma virus mediated immune response increases patient survival, which indirectly transmit human papilloma virus in future generations and act as a potential threat developing neurogenic disorders. METHODS: An objective based search strategy, following comprehensive and specific search approaches were made to retrieve recent 12 years research data from five different NCBI databases. Out of 300 shortlisted articles, only 24 principal studies met the inclusion criteria. RESULTS: Highest human papilloma virus prevalence (10.42 %) was found in South Asia, 5.8 % in South East Asia, 5.7 % East Asia, 2.5% in west Asia and no relevant updated data was found from central Asian continent. Highest prevalence (10%) of HPV genotype-16 was recorded in Asia among 3, 710 enrolled cases including 2201 males, 1149 females and 360 cases of unknown gender. While undifferentiated multiple HPV genotype prevalence was 5.5 % (204 cases). Lowest percentage of HPV sub-types 68, 72, 57, 39 were recorded respectively. Pakistan ranked top reporting highest number of HPV-16 cases, Taiwan HPV-18, India HPV-31, Japan HPV-35 and Singapore in HPV-16 and HPV-18 co-infection rates respectively. CONCLUSIONS: Exact prevalence of HPV associated head and neck squamous cell carcinomas among Asian population is still debatable. Due to higher heterogeneity (P< 0.00001), I2 = 81-88% at 95 % confidence interval), non-availability and limitations of reported studies from Asian sub-continents especially central Asia, western Asia and from south and south east Asia demand large scale collaborative research culture to standardize head and neck squamous cell carcinomas aetiology.
.

Differential expression of Helios, Neuropilin-1 and FoxP3 in head and neck squamous cell carcinoma (HNSCC) patients.

In recent years, studies have begun to explore the immune involvement in head and neck tumors. Advanced stage head and neck squamous cell carcinoma (HNSCC) has a poor prognosis with low survival rates with high level of immune infiltrates. Tregs (regulatory T cells) play a crucial role in constructing an immunosuppressive tumor microenvironment. In the present study, we highlighted specific Treg markers and its factors in HNSCC solid tumors and peripheral blood of cancer patients. By histopathology and immunofluorescence staining, we observed differential expression of CD4, CD25, Foxp3, Helios and Neuropilin-1. Further, we analyzed the expression of Foxp3, Helios, Neuropilin-1 and GARP by qPCR and flow cytometry in whole blood and found to be elevated in HNSCC patients in comparison with healthy donors. Additionally, IFN-γ, TGF-ß, IL-6, IL-2, IL-10 and TNF-α expressions were also found to be relatively increased in the head and neck cancer patients when compared with healthy donors. Our findings emphasize that Tregs may be involved in promoting tumor progression. Helios and Neuropilin-1 could be potent markers in identifying subsets of Tregs. Association of soluble factors could sculpture the activity of Tregs. With further research, Treg markers and its associated soluble factors could be employed to block Tregs trafficking to the tumor, thus enlightening a potential strategy for targeting human cancers.

Three distinct genomic subtypes of head and neck squamous cell carcinoma associated with clinical outcomes.

OBJECTIVES: Heterogeneity of head and neck squamous cell carcinomas (HNSCCs) results in unpredictable outcomes for patients with similar stages of cancer. Beyond the role of human papilloma virus (HPV), no validated molecular marker of HNSCCs has been established. Thus, clinically relevant molecular subtypes are needed to optimize HNSCC therapy. The purpose of this study was to identify subtypes of HNSCC that have distinct biological characteristics associated with clinical outcomes and to characterize genomic alterations that best reflect the biological and clinical characteristics of each subtype. MATERIALS AND METHODS: We analyzed gene expression profiling data from pan-SCC tissues including cervical SCC, esophageal SCC, lung SCC, and HNSCC (n = 1346) to assess the similarities and differences among SCCs and to identify molecular subtypes of HNSCC associated with prognosis. Subtype-specific gene expression signatures were identified and used to construct predictive models. The association of the subtypes with prognosis was validated in two independent cohorts of patients. RESULTS: Pan-SCC analysis identified three novel subtypes of HNSCC. Subtype 1 had the best prognosis and was similar to cervical SCC, whereas subtype 3 had the worst prognosis and was similar to lung SCC. Subtype 2 had a moderate prognosis. The 600-gene signature associated with the three subtypes significantly predicted prognosis in two independent validation cohorts. These three subtypes also were associated with potential benefit of immunotherapy. CONCLUSION: We identified three clinically relevant HNSCC molecular subtypes. Independent prospective studies to assess the clinical utility of the subtypes and associated gene signature are warranted.

Differences in the prognosis of HPV16-positive patients with squamous cell carcinoma of head and neck according to viral load and expression of P16.

PURPOSE: To evaluate the impact of HPV16 load (VL-the number of virus genome copies per cell) and P16 expression on prognosis of patients with squamous cell carcinomas (SCCs) of head and neck (HN). MATERIALS AND METHODS: HPV16 presence was assessed in the group of 109 patients with HNSCCs by quantitative polymerase chain reaction (qPCR). VL (assessed by qPCR) and P16 expression (evaluated by immunohistochemistry) were analysed only in the subgroup of HPV16-positive tumours. These features were correlated with 5-year overall survival (OS) and disease-free survival (DFS). RESULTS: HPV16 infection was found in 36 tumours (33.0%). Virus-positive patients had better OS and DFS than those without infection (P = 0.041 and 0.005). Among HPV16-positive HNSCCs, 18 (50.0%) had higher VL (median value > 6764.3 copies/cell) and 25 (73.5%) P16 over expression. The significant differences in OS and DFS (P = 0.008 and 0.004) were noticed according to VL, wherein 100% DFS was found for patients with higher VL. According to P16 expression, significant difference was found only for OS (P = 0.020). In multivariate analysis, VL (P = 0.045; HR = 2.795; CI 0.121-1.060) and the level of smoking (P = 0.023, HR = 2.253; CI 1.124-4.514) were independent factors affecting DFS of HPV16-positive patients. CONCLUSION: On the basis of viral load, it is possible to differentiate prognosis of patients with HPV16-positive HNSCCs. In this subgroup, viral load has stronger prognostic potential than P16 expression.

N-of-1-pathways MixEnrich: advancing precision medicine via single-subject analysis in discovering dynamic changes of transcriptomes.

BACKGROUND: Transcriptome analytic tools are commonly used across patient cohorts to develop drugs and predict clinical outcomes. However, as precision medicine pursues more accurate and individualized treatment decisions, these methods are not designed to address single-patient transcriptome analyses. We previously developed and validated the N-of-1-pathways framework using two methods, Wilcoxon and Mahalanobis Distance (MD), for personal transcriptome analysis derived from a pair of samples of a single patient. Although, both methods uncover concordantly dysregulated pathways, they are not designed to detect dysregulated pathways with up- and down-regulated genes (bidirectional dysregulation) that are ubiquitous in biological systems. RESULTS: We developed N-of-1-pathways MixEnrich, a mixture model followed by a gene set enrichment test, to uncover bidirectional and concordantly dysregulated pathways one patient at a time. We assess its accuracy in a comprehensive simulation study and in a RNA-Seq data analysis of head and neck squamous cell carcinomas (HNSCCs). In presence of bidirectionally dysregulated genes in the pathway or in presence of high background noise, MixEnrich substantially outperforms previous single-subject transcriptome analysis methods, both in the simulation study and the HNSCCs data analysis (ROC Curves; higher true positive rates; lower false positive rates). Bidirectional and concordant dysregulated pathways uncovered by MixEnrich in each patient largely overlapped with the quasi-gold standard compared to other single-subject and cohort-based transcriptome analyses. CONCLUSION: The greater performance of MixEnrich presents an advantage over previous methods to meet the promise of providing accurate personal transcriptome analysis to support precision medicine at point of care.

Epidermal Growth Factor Receptor (EGFR) and Keratin 5 (K5): Versatile Keyplayers Defining Prognostic and Therapeutic Sub-classes of Head and Neck Squamous Cell Carcinomas.

Molecular classifications of several malignancies are already accepted and applied in clinical practice. For head and neck squamous cell carcinomas (HNSCCs) there exist few and controversial data regarding their stratification on distinct groups or sub-groups and thus, none of them are validated as useful tools for diagnosis and therapy. Starting from the highly expressed markers in HNSCC (epidermal growth factor receptor, keratin 5 and E cadherin) we proposed to identify distinct HNSCC sub-groups with a potential impact on prognosis and therapy. Complex analysis of immunohistochemical expression for six surrogate markers (EGFR, p53, Bcl2, CD117, keratin 5 and E-cadherin) defined three distinct sub-classes amongst EGFR-positive cases, based on the association and differential expression of p53 and Bcl2 (EGFR(+)/p53(-)/bcl2(-), EGFR(+)/p53(+)/bcl2(-) and EGFR(+)/p53(+)/bcl2(+)). Amongst them, only the EGFR(+)/p53+/bcl2(-) sub-class showed significant correlations with grade and TNM parameters. Keratin 5-positive cases were grouped in a special "basal like" group with a particular sub-class rich in CD117(+)/p63(+) cells also highly expressing EGFR. Presence of K5(+)/CD117(+)/p63(+) cells was correlated with all TNM staging parameters defining a particular sub-class with high aggressiveness and particular behavior. Our data sustain EGFR as the key player in the pathogenesis of HNSCCs, but its diagnostic value may be improved by association with other prognostic or therapeutic markers. We herein defined two distinct HNSCCs groups (EGFR(+) and K5(+)) with several sub-classes, identifiable by the additional assessment of p53, Bcl2 and CD117.

Biological impact of superparamagnetic iron oxide nanoparticles for magnetic particle imaging of head and neck cancer cells.

BACKGROUND: As a tomographic imaging technology, magnetic particle imaging (MPI) allows high spatial resolution and sensitivity, and the possibility to create real-time images by determining the spatial distribution of magnetic particles. To ensure a prospective biosafe application of UL-D (University of Luebeck-Dextran coated superparamagnetic nanoparticles), we evaluated the biocompatibility of superparamagnetic iron oxide nanoparticles (SPIONs), their impact on biological properties, and their cellular uptake using head and neck squamous cancer cells (HNSCCs). METHODS: SPIONs that met specific MPI requirements were synthesized as tracers. Labeling and uptake efficiency were analyzed by hematoxylin and eosin staining and magnetic particle spectrometry. Flow cytometry, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays, and real-time cell analyzer assays were used to investigate apoptosis, proliferation, and the cytokine response of SPION-labeled cells. The production of reactive oxygen species (ROS) was determined using a fluorescent dye. Experimental results were compared to the contrast agent Resovist(®), a standard agent used in MPI. RESULTS: UL-D nanoparticles and Resovist particles were taken up in vitro by HNSCCs via unspecific phagocytosis followed by cytosolic accumulation. To evaluate toxicity, flow cytometry analysis was performed; results showed that dose- and time-dependent administration of Resovist induced apoptosis whereas cell viability of UL-D-labeled cells was not altered. We observed decreased cell proliferation in response to increased SPION concentrations. An intracellular production of ROS could not be detected, suggesting that the particles did not cause oxidative stress. Tumor necrosis factor alpha (TNF-α) and interleukins IL-6, IL-8, and IL-1ß were measured to distinguish inflammatory responses. Only the primary tumor cell line labeled with >0.5 mM Resovist showed a significant increase in IL-1ß secretion. CONCLUSION: Our data suggest that UL-D SPIONs are a promising tracer material for use in innovative tumor cell analysis in MPI.