Relationship between head and neck cancer therapy and some genetic endpoints

Manejo odontológico de las manifestaciones orales inducidas por radioterapia de cabeza y cuello

La radioterapia es una de las primeras opciones de tratamiento para el cáncer de cabeza y cuello; sin embargo, puede ocasionar diversas manifestaciones secundarias en la cavidad oral tales como mucositis oral, xerostomía, infecciones orales oportunistas, osteorradionecrosis y trismo. El presente artículo tiene como objetivo describir el manejo preventivo y terapéutico de las complicaciones orales inducidas por radioterapia de cabeza y cuello en la práctica odontológica propuestos hasta la actualidad. Se encontraron diversas medidas que han logrado reducir la incidencia y gravedad de dichas manifestaciones orales; sin embargo, aún existen algunas que requieren de más estudios para confirmar su efectividad. Palabras clave: cáncer de cabeza y cuello; manifestaciones bucales; radioterapia; terapéutica.

Radiation-induced neuropathies in head and neck cancer: prevention and treatment modalities

Head and neck cancer (HNC) is the sixth most common human malignancy with a global incidence of 650,000 cases per year. Radiotherapy (RT) is commonly used as an effective therapy to treat tumours as a definitive or adjuvant treatment. Despite the substantial advances in RT contouring and dosage delivery, patients suffer from various radiation-induced complications, among which are toxicities to the nervous tissues in the head and neck area. Radiation-mediated neuropathies manifest as a result of increased oxidative stress-mediated apoptosis, neuroinflammation and altered cellular function in the nervous tissues. Eventually, molecular damage results in the formation of fibrotic tissues leading to susceptible loss of function of numerous neuronal substructures. Neuropathic sequelae following irradiation in the head and neck area include sensorineural hearing loss, alterations in taste and smell functions along with brachial plexopathy, and cranial nerves palsies. Numerous management options are available to relieve radiation-associated neurotoxicities notwithstanding treatment alternatives that remain restricted with limited benefits. In the scope of this review, we discuss the use of variable management and therapeutic modalities to palliate common radiation-induced neuropathies in head and neck cancers.

Novel drug delivery system based on hollow mesoporous magnetic nanoparticles for head and neck cancers--targeted therapy in vitro and in vivo

Magnetic targeting delivery of anti-cancer drug with controlled drug release function has been recognized as a promising strategy for pursuit of the increased chemotherapeutic efficacy and reduced adverse effects. Superparamagnetic nano-carrier is proved to be an efficient manner for superficial tumor therapy like head and neck cancers. The anti-tumor effect of chemotherapy drug can be enhanced by combining with external magnet. Herein, we reported the fabrication and functionalization of biocompatible and superparamagnetic hollow mesoporous nanoparticles with magnetic targeting. The nanoparticles drug delivery system was constructed by surface-engineering polyacrylic acid (PAA) onto the superparamagnetic nanoparticles which can load bleomycin (BLM) both in the mesoporous structure and via bonding with PAA. The drug was targeted and retained to the focal area under the magnetic field with the nano-carriers, and released sustainably. Detailed investigations demonstrated that PAA-functionalized magnetite nanoparticles loading BLM could stimulate tumor cells to apoptosis locally. The drug loaded and delivery system endowed the anticancer drug with targeting capability in vitro and suppressed the growth of tumor in vivo. The present targeted drug delivery system is a rather simple method without sophisticated chemistry or materials engineering and is promising in contributing to the progress of nanotherapeutics toward efficient head and neck cancer treatment.

Targeting the XPO1-dependent nuclear export of E2F7 reverses anthracycline resistance in head and neck squamous cell carcinomas

Patient mortality rates have remained stubbornly high (40%) for the past 35 years in head and neck squamous cell carcinoma (HNSCC) due to inherent or acquired drug resistance. Thus, a critical issue in advanced SCC is to identify and target the mechanisms that contribute to therapy resistance. We report that the transcriptional inhibitor, E2F7, is mislocalized to the cytoplasm in >80% of human HNSCCs, whereas the transcriptional activator, E2F1, retains localization to the nucleus in SCC. This results in an imbalance in the control of E2F-dependent targets such as SPHK1, which is derepressed and drives resistance to anthracyclines in HNSCC. Specifically, we show that (i) E2F7 is subject to exportin 1 (XPO1)-dependent nuclear export, (ii) E2F7 is selectively mislocalized in most of SCC and multiple other tumor types, (iii) mislocalization of E2F7 in HNSCC causes derepression of Sphk1 and drives anthracycline resistance, and (iv) anthracycline resistance can be reversed with a clinically available inhibitor of XPO1, selinexor, in xenotransplant models of HNSCC. Thus, we have identified a strategy to repurpose anthracyclines for use in SCC. More generally, we provide a strategy to restore the balance of E2F1 (activator) and E2F7 (inhibitor) activity in cancer.

F2-isoprostanes can mediate bleomycin-induced lung fibrosis

F₂-isoprostanes (F₂-IsoPs) have been considered markers of oxidative stress in various pulmonary diseases, but little is known about their possible role in pulmonary fibrosis. In this study, we have investigated the potential key role of F₂-IsoPs as markers and mediators of bleomycin (BLM)-induced pulmonary fibrosis in rats. During the in vivo study, plasma F₂-IsoPs showed a peak at 7 days and remained elevated for the entire experimental period. Lung F₂-IsoP content nearly tripled 7 days following the intratracheal instillation of BLM, and by 28 days, the value increased about fivefold compared to the controls. Collagen deposition correlated with F₂-IsoP content in the lung. Furthermore, from day 21 onwards, lung sections from BLM-treated animals showed α-smooth muscle actin (α-SMA) positive cells, which were mostly evident at 28 days. In vitro studies performed in rat lung fibroblasts (RLF) demonstrated that either BLM or F₂-IsoPs stimulated both cell proliferation and collagen synthesis. Moreover, RLF treated with F₂-IsoPs showed a significant increase of α-SMA expression compared to control, indicating that F₂-IsoPs can readily activate fibroblasts to myofibroblasts. Our data demonstrated that F₂-IsoPs can be mediators of key events for the onset and development of lung fibrosis, such as cell proliferation, collagen synthesis and fibroblast activation. Immunocytochemistry analysis, inhibition and binding studies demonstrated the presence of the thromboxane A₂ receptor (TP receptor) on lung fibroblasts and suggested that the observed effects may be elicited through the binding to this receptor. Our data added a new perspective on the role of F₂-IsoPs in lung fibrosis by providing evidence of a profibrotic role for these mediators in the pathogenesis of pulmonary fibrosis.

GTSP1 expression in non-smoker and non-drinker patients with squamous cell carcinoma of the head and neck

Introduction

The main risk factors for head and neck squamous cell carcinoma (HNSCC) are tobacco and alcohol consumption and human papillomavirus (HPV) infection. However, in a subset of patients, no risk factors can be identified. Glutathione S-transferase π (GTSP1) is a carcinogen-detoxifying enzyme that is activated by exposure to carcinogens, and it is associated with a reduction in response to toxic therapies. We studied the expression of GTSP1 in tumor and non-tumor tissue samples from patients with and without these risks to identify whether GTSP1 expression differs according to exposure to carcinogens.

Materials and methods

Non-smoker/non-drinker (NSND) and smoker/drinker (SD) patients were matched according to age, gender, tumor site, TNM stage, grade and histological variants to establish 47 pairs of patients who have been previously tested for HPV. GTSP1 immunostaining was analyzed using a semi-quantitative method with scores ranging from 0 to 3 according to the area of immunostaining.

Results

GTSP1 expression was detected in the tumors of both groups. GTSP1 expression was higher in the non-tumor margins of SD patients (p = 0.004). There was no association between GTSP1 expression and positivity for HPV. No differences in survival were observed according to GTSP1 staining in tumors and non-tumor margins.

Conclusion

This study showed that GTSP1 was expressed in tumors of HNSCC patients regardless of smoking, drinking or HPV infection status. The difference in GTSP1 expression in non-tumor margins between the two groups may have been due to two possible reasons. First, elevated GTSP1 expression in SD patients might be the result of activation of GTSP1 in response to exposure to carcinogens. Second, alternatively, impairment in the detoxifying system of GTSP1, as observed by the reduced expression of GTSP1, might make patients susceptible to carcinogens other than tobacco and alcohol, which may be the underlying mechanism of carcinogenesis in the absence of risk factors.

Exploring the mechanism of WWOX growth inhibitory effects on oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most common types of head and neck neoplasms in the world. Patients diagnosed with OSCC exhibit a poor prognosis. WW domain-containing oxidoreductase (WWOX), as a candidate tumor-suppressor gene, is involved in the genesis and progression of tumors. The deletion of the WWOX gene has been identified in OSCC and oral leukoplakia, but the function and mechanism of WWOX in OSCC remain unknown. Therefore, the present study investigated the role of WWOX in oral squamous carcinoma cells. The results revealed that an elevation of WWOX expression had an inhibitory effect on the growth of three types of oral squamous carcinoma cells, with the most evident effect occurring in Tca8113 cells. Also, in the Tca8113 cells, WWOX overexpression significantly inhibited colony formation, and induced apoptosis and cell cycle arrest. Microarray analysis, reverse transcription-quantitative polymerase chain reaction and western blotting methods detected that WWOX overexpression contributed to the differential expression of the genes involved in mediating the extracellular-signal regulated protein kinase/mitogen-activated protein kinase (ERK/MAPK) signaling pathway. These results suggest that the tumor-suppressor function of the WWOX gene may be associated with the modulation of the ERK/MAPK signaling pathway, thus providing a novel target for OSCC therapy.

A Tetrameric Peptide Derived from Bovine Lactoferricin Exhibits Specific Cytotoxic Effects against Oral Squamous-Cell Carcinoma Cell Lines

Several short linear peptides derived from cyclic bovine lactoferricin were synthesized and tested for their cytotoxic effect against the oral cavity squamous-cell carcinoma (OSCC) cell lines CAL27 and SCC15. As a control, an immortalized and nontumorigenic cell line, Het-1A, was used. Linear peptides based on the RRWQWR core sequence showed a moderate cytotoxic effect and specificity towards tumorigenic cells. A tetrameric peptide, LfcinB(20–25)₄, containing the RRWQWR motif, exhibited greater cytotoxic activity (>90%) in both OSCC cell lines compared to the linear lactoferricin peptide or the lactoferrin protein. Additionally, this tetrameric peptide showed the highest specificity towards tumorigenic cells among the tested peptides. Interestingly, this effect was very fast, with cell shrinkage, severe damage to cell membrane permeability, and lysis within one hour of treatment. Our results are consistent with a necrotic effect rather than an apoptotic one and suggest that this tetrameric peptide could be considered as a new candidate for the therapeutic treatment of OSCC.

Emerging drugs for head and neck cancer

INTRODUCTION

Despite improvements in treatment, survival rates of head and neck squamous cell carcinoma (HNSCC) are stagnant. The existing chemotherapeutic agents are non-selective and associated with toxicities. Combinations of the only the US FDA-approved epidermal growth factor receptor (EGFR)-targeted agent, cetuximab, with chemotherapy or radiation improves overall survival. However, the response rates to cetuximab are modest. Thus, there is an urgent need for new agents that can be safely integrated into current treatment regimens to improve outcome.

AREAS COVERED

Current EGFR-targeted drugs under clinical development include mAbs and tyrosine kinase inhibitors. The modest efficacy of these drugs implicates intrinsic or acquired resistance. Novel molecular agents inhibiting alternative targets to overcome anti-EGFR resistance in HNSCC are under investigation. Gene therapy and immunotherapy are also promising strategies to improve efficacy and reduce toxicity.

EXPERT OPINION

To date, only six drugs have been FDA-approved for the treatment of head and neck cancer. Cetuximab is the only approved molecular targeting agent for HNSCC and despite ubiquitous expression of EGFR in HNSCC tumors, clinical responses are limited. Genetic and epigenetic characterization of HNSCC tumors, coupled with improved preclinical models, should facilitate the development of more effective drugs.

A novel E2F/sphingosine kinase 1 axis regulates anthracycline response in squamous cell carcinoma

PURPOSE

Head and neck squamous cell carcinomas (HNSCC) are frequently drug resistant and have a mortality rate of 45%. We have previously shown that E2F7 may contribute to drug resistance in SCC cells. However, the mechanism and pathways involved remain unknown.

EXPERIMENTAL DESIGN

We used transcriptomic profiling to identify candidate pathways that may contribute to E2F7-dependent resistance to anthracyclines. We then manipulated the activity/expression of the candidate pathway using overexpression, knockdown, and pharmacological inhibitors in in vitro and in vivo models of SCC to demonstrate causality. In addition, we examined the expression of E2F7 and a downstream effector in a tissue microarray (TMA) generated from HNSCC patient samples.

RESULTS

E2F7-deficient keratinocytes were selectively sensitive to doxorubicin and this was reversed by overexpressing E2F7. Transcriptomic profiling identified Sphingosine kinase 1 (Sphk1) as a potential mediator of E2F7-dependent drug resistance. Knockdown and overexpression studies revealed that Sphk1 was a downstream target of E2F7. TMA studies showed that E2F7 overexpression correlated with Sphk1 overexpression in human HNSCC. Moreover, inhibition of Sphk1 by shRNA or the Sphk1-specific inhibitor, SK1-I (BML-EI411), enhanced the sensitivity of SCC cells to doxorubicin in vitro and in vivo. Furthermore, E2F7-induced doxorubicin resistance was mediated via Sphk1-dependent activation of AKT in vitro and in vivo.

CONCLUSION

We identify a novel drugable pathway in which E2F7 directly increases the transcription and activity of the Sphk1/S1P axis resulting in activation of AKT and subsequent drug resistance. Collectively, this novel combinatorial therapy can potentially be trialed in humans using existing agents.