Whole-exome sequencing identifies multiple loss-of-function mutations of NF-κB pathway regulators in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy with a unique geographical distribution. The genomic abnormalities leading to NPC pathogenesis remain unclear. In total, 135 NPC tumors were examined to characterize the mutational landscape using whole-exome sequencing and targeted resequencing. An APOBEC cytidine deaminase mutagenesis signature was revealed in the somatic mutations. Noticeably, multiple loss-of-function mutations were identified in several NF-κB signaling negative regulators NFKBIA, CYLD, and TNFAIP3 Functional studies confirmed that inhibition of NFKBIA had a significant impact on NF-κB activity and NPC cell growth. The identified loss-of-function mutations in NFKBIA leading to protein truncation contributed to the altered NF-κB activity, which is critical for NPC tumorigenesis. In addition, somatic mutations were found in several cancer-relevant pathways, including cell cycle-phase transition, cell death, EBV infection, and viral carcinogenesis. These data provide an enhanced road map for understanding the molecular basis underlying NPC.

Predictors for Frey Syndrome Development After Parotidectomy.

BACKGROUND: Frey syndrome is a common complication after parotidectomy. The aim of this study is to investigate potential predictors for development of Frey syndrome and explore their implications in additional prophylactic procedures. To the best of our knowledge, this is the first study to address these issues. METHODS: A computer search was performed to identify all patients who received parotidectomy from January 2009 to December 2011 in Queen Mary Hospital, Hong Kong. Individual case notes were reviewed to retrieve details for analysis. RESULTS: A total of 155 parotidectomies were identified. Tumor size was the only statistically significant clinical predictor (Frey group: 43.5 ± 38.4 mm vs No Frey group: 33.1 ± 27.5 mm; P = 0.018). Disease pathology, type of resection, and previous treatments such as radiotherapy or parotidectomy did not appear to be associated with development of Frey syndrome.Post hoc analysis of our data showed that Frey incidence nearly doubled in patients with tumor size of 4 cm or greater (33%) compared to those with tumors that sized less than 4 cm (18%). CONCLUSIONS: Frey syndrome is common after parotidectomy. Tumor size is the only statistically significant predictor of its development. Routine preventive interventions, for example, use of acellular dermal matrix, dermofat graft or muscle flaps to prevent Frey syndrome, should be considered for high risk patients.

Application of Palpebral Spring in Asian Patients With Paralytic Lagophthalmos.

PURPOSE: Literature on palpebral springs is scarce, and even more so for the Asian population. In this study, the authors evaluated their experience with palpebral spring placement for paralytic lagophthalmos in an Asian population. The authors report the unique challenges encountered due to the distinctive features in Asian eyelids and how they overcome them. To the best of our knowledge, this is the first report on the application of palpebral springs in Asians. METHODS: All patients treated for paralytic lagophthalmos in the Department of Surgery, Queen Mary Hospital, from November 2013 to December 2015, were included in this study. The authors retrieved and analyzed the demographic data, preoperative assessment details, and treatment outcomes. RESULTS: A total of 17 patients were recruited. The median interval between facial palsy occurrence and surgery was 66 months. Preoperatively, vertical palpebral fissure was 12.3 ± 1.7 mm with margin reflex distance 1 of 3.7 ± 0.3 mm and margin reflex distance 2 of 8.6 ± 1.6 mm. Lagophthalmos before surgery was 9.6 ± 2.3 mm. After the palpebral spring surgeries, vertical palpebral fissure was reduced to 9.1 ± 1.4 mm. margin reflex distance 1 is slightly reduced (3.3 ± 0.8 mm) and margin reflex distance 2 improved to 5.8 ± 1.0 mm. Lagophthalmos reduced significantly to 0.8 ± 1.3 mm. Seven patients required revision procedures. CONCLUSIONS: Palpebral spring is a safe and effective treatment for Asian patients with paralytic lagophthalmos. However, surgeons should be aware of the unique challenges associated with the anatomy of Asian eyelids. Special adaptation of the procedure is required to optimize the outcome.

Clinical Patterns of Melanoma in Asians: 11-Year Experience in a Tertiary Referral Center.

BACKGROUND: Malignant melanoma is a relatively common malignancy in the West, but has a significantly lower incidence in Asians. Stark contrast in clinicopathological characteristics and prognosis has been observed between the 2 populations, yet data are limited. Here, we evaluate 106 Asian patients from a tertiary referral center in Hong Kong during an 11-year period. The purpose of this study was to collectively review all types of melanomas to analyze the clinicopathological characteristics of this poorly understood condition in an Asian population. METHODS: A total of 106 patients diagnosed with malignant melanoma from 2002 to 2012 were retrospectively reviewed. Demographics, clinical presentations, pathological subtypes, treatments, and survival outcomes were evaluated. RESULTS: Cutaneous melanomas dominated with 46 (43.4%) cases, followed by mucosal (39.6%), ocular (9.4%), and melanomas of unknown primary (7.5%); 43.3% patients presented in stage I, 36.7% in stage II, 18.9% in stage III, and 1.1% in stage IV. Acral lentiginous melanoma was the commonest subtype of cutaneous melanomas (60.9%). When types of melanomas were reviewed collectively, the median overall survival, disease-specific survival, and recurrence-free survival were 37, 45, and 48 months, respectively. Cutaneous melanoma had the best median overall survival of 59 months, followed by ocular melanoma (58 months), mucosal melanoma (18 months), and melanoma of unknown primary (2 months). Similar patterns were observed for disease-specific survival and recurrence-free survival. CONCLUSIONS: Melanoma among Asians remains poorly understood. There is a clear distinction in the clinical patterns between Asians and whites and the difference is not solely accounted for by the lower incidence of cutaneous melanoma. Certain subtypes, such as mucosal melanoma and is acral lentiginous melanoma, seemed to have disproportionately high incidences. Further studies are warranted to elucidate these observations. The poor survival outcomes reflected the need for better awareness and understanding of the condition by both the general public and the physicians.

IL-1ß promotes malignant transformation and tumor aggressiveness in oral cancer.

Chronic inflammation, coupled with alcohol, betel quid, and cigarette consumption, is associated with oral squamous cell carcinoma (OSCC). Interleukin-1 beta (IL-1ß) is a critical mediator of chronic inflammation and implicated in many cancers. In this study, we showed that increased pro-IL-1ß expression was associated with the severity of oral malignant transformation in a mouse OSCC model induced by 4-Nitroquinolin-1-oxide (4-NQO) and arecoline, two carcinogens related to tobacco and betel quid, respectively. Using microarray and quantitative PCR assay, we showed that pro-IL-1ß was upregulated in human OSCC tumors associated with tobacco and betel quid consumption. In a human OSCC cell line TW2.6, we demonstrated nicotine-derived nitrosamine ketone (NNK) and arecoline stimulated IL-1ß secretion in an inflammasome-dependent manner. IL-1ß treatment significantly increased the proliferation and dysregulated the Akt signaling pathways of dysplastic oral keratinocytes (DOKs). Using cytokine antibodies and inflammation cytometric bead arrays, we found that DOK and OSCC cells secreted high levels of IL-6, IL-8, and growth-regulated oncogene-α following IL-1ß stimulation. The conditioned medium of IL-1ß-treated OSCC cells exerted significant proangiogenic effects. Crucially, IL-1ß increased the invasiveness of OSCC cells through the epithelial-mesenchymal transition (EMT), characterized by downregulation of E-cadherin, upregulation of Snail, Slug, and Vimentin, and alterations in morphology. These findings provide novel insights into the mechanism underlying OSCC tumorigenesis. Our study suggested that IL-1ß can be induced by tobacco and betel quid-related carcinogens, and participates in the early and late stages of oral carcinogenesis by increasing the proliferation of dysplasia oral cells, stimulating oncogenic cytokines, and promoting aggressiveness of OSCC.

Active replication of Middle East respiratory syndrome coronavirus and aberrant induction of inflammatory cytokines and chemokines in human macrophages: implications for pathogenesis.

Middle East respiratory syndrome coronavirus (MERS-CoV) infection caused severe pneumonia and multiorgan dysfunction and had a higher crude fatality rate (around 50% vs. 10%) than SARS coronavirus (SARS-CoV) infection. To understand the pathogenesis, we studied viral replication, cytokine/chemokine response, and antigen presentation in MERS-CoV-infected human monocyte-derived macrophages (MDMs) versus SARS-CoV-infected MDMs. Only MERS-CoV can replicate in MDMs. Both viruses were unable to significantly stimulate the expression of antiviral cytokines (interferon α [IFN-α] and IFN-ß) but induced comparable levels of tumor necrosis factor α and interleukin 6. Notably, MERS-CoV induced significantly higher expression levels of interleukin 12, IFN-γ, and chemokines (IP-10/CXCL-10, MCP-1/CCL-2, MIP-1α/CCL-3, RANTES/CCL-5, and interleukin 8) than SARS-CoV. The expression of major histocompatibility complex class I and costimulatory molecules were significantly higher in MERS-CoV-infected MDMs than in SARS-CoV-infected cells. MERS-CoV replication was validated by immunostaining of infected MDMs and ex vivo lung tissue. We conclusively showed that MERS-CoV can establish a productive infection in human macrophages. The aberrant induction of inflammatory cytokines/chemokines could be important in the disease pathogenesis.

Curcumin exerts inhibitory effects on undifferentiated nasopharyngeal carcinoma by inhibiting the expression of miR-125a-5p.

Curcumin suppresses proliferation, migration, invasion, metastasis and angiogenesis and induces apoptosis by regulating multiple signalling pathways and miRNAs in a wide variety of human malignancies. miRNAs play crucial roles in various steps of carcinogenesis in nasopharyngeal carcinoma (NPC); thus, they could serve as critical therapeutic targets for NPC treatment. Curcumin could provide a novel strategy to block or induce specific miRNAs for miRNA-based gene therapies. Nevertheless, there are no reports to date on the miRNAs regulated by curcumin in NPC. In the present study, we have carried out an miRNA microarray to identify the miRNAs regulated by curcumin in NPC. Curcumin treatment down-regulated the expression of hsa-miR-125a-5p, hsa-miR-574-3p and hsa-miR-210 as determined by miRNA microarray analysis and qPCR (real-time quantitative reverse transcription-PCR). Forced expression of miR-125a-5p enhanced proliferation, migration and invasion of HONE1 cells. Primary NPC exhibited a significantly higher expression level of miR-125a-5p than healthy controls. miR-125a-5p inhibited the expression of tumour protein 53 (TP53), and curcumin treatment up-regulated the expression of TP53. Taken together, these results indicate that curcumin exerted inhibitory effects on NPC by inhibiting the expression of miR-125a-5p and, subsequently, enhancing the expression of TP53. Curcumin could provide a novel strategy to block miR-125a-5p for miRNA-based gene therapies in NPC.

Epigenetic regulation of the X-linked tumour suppressors BEX1 and LDOC1 in oral squamous cell carcinoma.

The strong associations between oral squamous cell carcinoma (OSCC) and dietary habits such as alcohol consumption (A), betel quid chewing (B) and cigarette smoking (C) and its predominance in men have been well documented; however, systemic analysis of OSCC is limited. Our study applied high-throughput screening methods to identify causative epigenetic targets in a cohort of men with ABC-associated OSCC. We identified BEX1 and LDOC1 as two epigenetically silenced X-linked tumour suppressors and demonstrated a functional link between the transcription of BEX1 and LDOC1 and promoter hypermethylation. Methylation of the BEX1 and LDOC1 promoters was associated significantly (p < 0.0001) with OSCC and were detected in 75% (42/56) and 89% (50/56) of the samples, respectively. We observed concordant increases in the methylation of both genes in 71% (40/56) of the tumours, and potent in vitro and in vivo growth inhibitory effects in OSCC cells ectopically expressing BEX1 and/or LDOC1. Restored expression of BEX1 and LDOC1 suppressed the nuclear factor-κB (NF-κB) signalling pathway, which is the most frequently hyperactivated signalling pathway in OSCC. This suppression might result from decreased p50 and p65 expression. These findings suggest that silencing of BEX1 and LDOC1 by promoter hypermethylation might represent a critical event in the molecular pathogenesis of OSCC and account for the oncogenic effects of ABC exposure and the male predominance of OSCC occurrence. Microarray data are available in the Gene Expression Omnibus (GEO; http://www.ncbi.nlm.nih.gov/geo/)

Efficacy of neck dissection in the management of isolated nodal recurrence after head and neck cancer treatment.

The status of the regional cervical lymphatics is one of the most significant prognostic indicators in head and neck cancers. The traditional treatment for cancers with cervical nodal metastasis has been surgical. With the global trend towards organ-preserving therapy, chemoradiation has gained increasing popularity over primary surgical therapies for cancers in the head and neck region. The subsequent management of the neck for those with residual or recurrent nodal metastasis, however, has become one of the most debated topics in the field of head and neck oncology. This review addressed several important controversies, including the optimal assessment of the nodal response to chemoradiation, the potential role and the oncological results of planned and salvage neck dissection after chemoradiation, as well as the type and extent of neck dissection required in order to achieve the optimal balance between tumour control and surgical morbidities. Further clinical trials and on-going research will help us to define the best therapeutic option in such circumstances.

Curcumin inhibits tongue carcinoma cells migration and invasion through downregulation of matrix metallopeptidase 10.

Squamous cell carcinoma (SCC) of tongue is an aggressive head and neck cancer with high propensity of regional spreading and invasion. Tongue carcinoma cells treated with curcumin, the major curcuminoid of the turmeric, demonstrated reduction in adhesion, migration, and invasion ability. High-throughput microarray analysis indicated that curcumin treatment suppressed matrix metallopeptidase 10 (MMP10) expression. MMP10 is overexpressed in tongue carcinoma tissues in comparison with the normal epithelia. Curcumin treatment on tongue carcinoma cell lines suppressed MMP10 expression at both mRNA and protein levels. Our results suggested that curcumin is a promising inhibitor to tongue cancer cells migration and invasion.

Biomarkers for use in monitoring responses of nasopharyngeal carcinoma cells to ionizing radiation.

Nasopharyngeal carcinoma (NPC) is a common head and neck cancer. The incidence rate is higher in southern China and Southeast Asia in comparison with the Western countries. Radiotherapy is the standard treatment of NPC as the cancer cells are sensitive to ionizing radiation. Radiation treatment has good local control to patients with early NPC. It is essential to monitor the response of the NPC cells to radiation treatment in advance in order to select suitable treatment choice for the patients. This review aims to discuss the potential use of biomarkers in monitoring the responsiveness of NPC cells to radiation treatment.

Mitochondrial DHODH regulates hypoxia-inducible factor 1 expression in OTSCC.

Oral tongue squamous cell carcinoma (OTSCC) was one of the most hypoxic tumors with unfavorable outcomes. Hypoxia-inducible factor-1 (HIF-1) signaling was associated with cancer proliferation, lymph node metastasis, angiogenesis and poor prognosis of OTSCC. Dihydroorotate dehydrogenase (DHODH) catalyzed the rate-limiting step in the de novo pyrimidine biosynthesis. The aim of the study was to explore the biological function of DHODH and investigate whether DHODH regulated HIF-1 signaling in OTSCC. Proliferation, migration and anoikis resistance were used to determine the function of DHODH. Western blot and luciferase activity assays were used to determine the regulatory role of DHODH on HIF-1. We found that increased DHODH expression was associated with advanced tumor stage and poorly differentiated tumor in head and neck cancer patients in The Cancer Genome Atlas (TCGA). DHODH enhanced the proliferation and aggressiveness of OTSCC. Moreover, DHODH prompted tumor growth and metastasis in vivo. DHODH promoted transcription, protein stability, and transactivation activity of HIF1A. DHODH-induced HIF1A upregulation in OTSCC can be reversed by reactive oxygen species (ROS) scavenger, indicating that DHODH enhanced HIF1A expression via ROS production. DHODH inhibitor suppressed DHODH-mediated ROS generation and HIF1A upregulation. Targeting DHODH using clinically available inhibitor, atovaquone, might provide a new strategy to treat OTSCC.

Robot-assisted real-time sentinel lymph node mapping in oral cavity cancer: preliminary experience.

This study aims to assess the feasibility of using indocyanine green and robotic near infra-red fluorescent imaging (Firefly®) for sentinel lymph node biopsy in cN0 oral cavity cancer. Ten patients with early squamous cell carcinoma of the tongue (n = 8) and buccal mucosa (n = 2) were included. Peritumoral injection of 10 mg indocyanine green and real-time mapping of sentinel lymph nodes in the neck was performed using Firefly® via a retro-auricular trans-hairline incision. Sentinel lymph node was detected in all patients at 1.2 sentinel lymph node per person. Majority were situated in level II (91.7%). Mean time to detection of sentinel lymph node was 171.0 (68.0-312.0)s. Mean signal-to-background ratio was 5.62 (3.51-7.91). Frozen section of one sentinel lymph node was positive for malignancy, paraffin section of which confirmed the presence of metastatic disease. Modified radical neck dissection was performed for that particular patient, paraffin section of which did not show any tumor deposit. Frozen section and paraffin section of all other sentinel lymph nodes (n = 11) and neck dissection specimens yielded no malignancy. All resection margins were clear. Three patients completed adjuvant radiotherapy for pT2N0 (n = 2) and pT2N1 (n = 1) carcinoma of the tongue. Mean follow-up was 12.0 (4.0-18.0) months. All patients were alive at last follow-up with no disease recurrence. There were no adverse outcomes associated with the use of indocyanine green and robot-assisted neck dissection. Indocyanine green and Firefly® for sentinel lymph node biopsy in cN0 oral cavity cancer is feasible with no adverse effects.

Novel approach to reduce SARS-CoV-2 transmission during trans-oral robotic surgery.

This study describes a novel approach in the reduction of SARS-CoV-2 transmission during trans-oral robotic surgery (TORS). Eight patients underwent TORS between 01 February 2020 and 07 September 2020. A sterile plastic sheet draped over sterile supports with water-tight seal around each cannula was used to create a sterile working space within which the robotic arms could freely move during operation. This set-up acts as an additional physical barrier against droplet and aerosol transmission. Operative diagnosis; droplet count and distribution on plastic sheet and face shields of console and assistant surgeons, and scrub nurse were documented. TORS tumour excision was performed for patients with suspected tonsillar tumour (n = 3) and tongue base tumour (n = 2). TORS tonsillectomy and tongue base mucosectomy was performed for cervical nodal metastatic carcinoma of unknown origin (n = 3). Droplet contamination was noted on all plastic drapes (n = 8). Droplet contamination was most severe over the central surface at 97.2% (91.7-100.0%), with the highest droplet count along the centre-most column where it overlies the site of operation in the oral cavity 33.3% (n = 31). Droplet count decreased towards the periphery. Contamination rate was 2.8% (0.0-8.3%) over the right lateral surface. There was no droplet contamination over the vertex and left lateral surface of plastic drapes. No droplet contamination was noted on face shields of all parties. The use of sterile plastic drapes with water-tight seal around each robotic cannula can help reduce viral transmission to healthcare providers during TORS.

Extracranial/Intracranial Vascular Bypass in the Treatment of Head and Neck Cancer - Related Carotid Blowout Syndrome.

OBJECTIVE/HYPOTHESIS: To investigate the endovascular intervention or extracranial/intracranial (EC/IC) vascular bypass in the management of patients with head and neck cancer-related carotid blowout syndrome (CBS). STUDY DESIGN: Retrospective case series. METHODS: Retrospective analysis of clinical data of patients with head and neck cancer-related CBS treated by endovascular intervention and/or EC/IC vascular bypass, analysis of its bleeding control, neurological complications, and survival results. RESULTS: Thrity-seven patients were included. Twenty-five were associated with external carotid artery (ECA); twelve were associated with internal or common carotid artery (ICA/CCA). All patients with ECA hemorrhage were treated with endovascular embolization. Of the 12 patients with ICA/CCA hemorrhage, 9 underwent EC/IC bypass, 1 underwent endovascular embolization, and 3 underwent endovascular stenting. For patients with ECA-related CBS, the median survival was 6 months, and the 90-day, 1-year, and 2-year survival rates were 67.1%, 44.7%, and 33.6%, respectively; the estimated rebleeding risk at 1-month, 6-month, and 2-year was 7.1%, 20.0%, and 31.6%, respectively. For patients with ICA/CCA-related CBS, the median survival was 22.5 months, and the 90-day, 1-year, and 2-year survival rates were 92.3%, 71.8%, and 41.0%, respectively; the estimated rebleeding risk at 1 month, 6 months, and 2 years is 7.7%,15.4%, and 15.4%, respectively. ICA/CCA-related CBS patients have significantly longer survival time and lower risk of rebleeding, which may be related to the more use of EC/IC vascular bypass as a definite treatment. CONCLUSIONS: For patients with ICA/CCA-related CBS, if there is more stable hemodynamics, longer expected survival, EC/IC vascular bypass is preferred. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:1548-1556, 2021.

The changing role of pectoralis major flap in head and neck reconstruction.

Although pectoralis major flap (PM flap) has been used as the workhorse flap in head and neck reconstruction, its use in head and neck defects seems to fall out of favour in the era of free tissue transfer. The aim of this review is to find out the role of PM flap in modern head and neck surgery. Medical records of patients who underwent PM flap reconstruction for head and neck defect in our division were reviewed. The age, gender, flap type, indication and complication rate were described. Between January 1998 and December 2008, 202 PM flaps were used for head and neck reconstruction in 192 patients. In the early study period (1998-June 2003), out of the 119 PM flap reconstructions, 106 (89%) were performed for immediate reconstruction after resection of head and neck tumour, while 10 (8%) were performed as salvage procedures for complication after tumour resection e.g. failure of free flap, pharyngocutaneous fistula. In the late study period (July 2003-2008), out of the 83 PM flap reconstructions, 58 (70%) were performed for immediate reconstruction, while 24 (29%) were performed as salvage procedures. For immediate reconstruction after tumour extirpation, 51 flaps (48%) were performed for reconstruction of the tongue in the early study period, while only 14 (24%) were performed in the late study period. The number of PM flap used for immediate reconstruction for other head and neck defects remained relatively static throughout the two study periods. Over the study period, there were 10 (5%) cases of partial flap necrosis and 2 (1%) total flap loss, making the overall flap necrosis rate 6%. In the era of free tissue transfer, the role of PM flap in head and neck surgery has shifted from immediate reconstruction to salvage operation. However, PM flap still has an unique role in the repair of certain head and neck defects.

CD38 triggers inflammasome-mediated pyroptotic cell death in head and neck squamous cell carcinoma.

BACKGROUND: Pyroptosis is a form of inflammatory cell death. Although it is recognized that NLRP3 (nucleotide-binding domain, leucine-rich repeat-containing family, pyrin domain-containing 3) inflammasome is involved in pyroptosis activation, the mechanism by which head and neck squamous cell carcinoma (HNSCC) inhibits pyroptotic cell death remains undefined. This study aims to delineate the role of calcium regulator CD38 in NLRP3 inflammasome-dependent pyroptosis in HNSCC. METHODS: CD38 overexpressing HNSCC cell lines (SAS, CAL27, SNU899) were generated using lentiviral vectors. NLRP3 and gasdermin D (GSDMD) quantity were detected using Western blot. Caspase-1 activity changes were measured using the Caspase-Glo® 1 inflammasome assay. Cell death proportion was determined by flow cytometry analysis. Proliferation assay was performed using xCELLigence RTCA system. Mouse xenotransplantation was performed to evaluate the potential oncogenic or tumor-suppressive function of CD38. ChIP assay was conducted to verify whether transcription factor NFAT1-mediated NLRP3 expression. RESULTS: Exogenous calcium treatment can lead to a significant increase in caspase-1 activity in HNSCC. This feature was also observed in HNSCC cells with stable CD38 overexpression. CD38-overexpressing cell lines showed a significant reduction in proliferation. Further, expression of NLRP3 protein level was significantly increased in CD38-overexpressing cell lines. The N-terminal effector domain of GSDMD was remarkably increased in the CD38-overexpressing HNSCC. ChIP assay indicated that calcium-sensitive transcription factor NFAT1 was possibly involved in the transcriptional upregulation of NLRP3 observed in CD38-overexpressing HNSCC. The pre-clinical xenograft model revealed that CD38 expression had an inhibiting function on HNSCC progression. CONCLUSION: In conclusion, our results suggested that activation of pyroptosis in HNSCC is a calcium-dependent process. Reduced expression of calcium ion regulator CD38 functions could prevent inflammasome-induced pyroptosis in HNSCC. CD38 may function as a tumor suppressor in HNSCC progression.

NADPH oxidase 5α promotes the formation of CD271 tumor-initiating cells in oral cancer.

Oral tongue squamous cell carcinoma (OTSCC) has a distinctive cell sub-population known as tumor-initiating cells (TICs). CD271 is a functional TIC receptor in head and neck cancers. The molecular mechanisms governing CD271 up-regulation remains unclear. Oxidative stress is a contributing factor in TIC development. Here, we explored the potential role of NADPH oxidase 5 (NOX5) and its regulatory mechanism on the development of CD271-expressing OTSCC. Our results showed that the splice variant NOX5α is the most prevalent form expressed in head and neck cancers. NOX5α enhanced OTSCC proliferation, migration, and invasion. Overexpression of NOX5α increased the size of OTSCC xenograft significantly in vivo. The tumor-promoting functions of NOX5α were mediated through the reactive oxygen species (ROS)-generating property. NOX5α activated ERK singling and increased CD271 expression at the transcription level. Also, NOX5α reduces the sensitivity of OTSCC to cisplatin and natural killer cells. The findings indicate that NOX5α plays an important part in the development of TIC in OTSCC.

Mature miR-184 and squamous cell carcinoma of the tongue.

Human microRNA 184 (miR-184) is overexpressed in squamous cell carcinoma (SCC) of the tongue. In vitro inhibition of miR-184 levels could induce apoptosis and hinder proliferation of tongue SCC cells. Patients with tongue SCC have high plasma miR-184 levels. Plasma miR-184 is likely associated with the tumor load. Surgical removal of the primary tumor reduced plasma miR-184 levels significantly. The data suggested that miR-184 is linked to the pathogenesis of tongue SCC. Further studies are warranted to evaluate the use of microRNA-based serological markers in monitoring tongue SCC.

Curcumin enhances cisplatin sensitivity by suppressing NADPH oxidase 5 expression in human epithelial cancer.

Cisplatin-based chemotherapy regimens serve a pivotal role in human cancer treatment. Nevertheless, treatment failure may occur if the cancer is inherently resistant to cisplatin or acquires a resistant phenotype during the course of treatment. Although cisplatin resistance can hinder the efficacy of cisplatin treatment for human cancer, the underlying mechanism remains poorly understood. The current study established a cisplatin-resistant human epithelial cancer cell line. Notably, differential upregulation of NADPH oxidase 5 (NOX5) was identified in this resistant cell line. Furthermore, cisplatin treatment induced cancer cells to express NOX5 and cells that overexpressed NOX5 exhibited greater resistance to cisplatin via the activation of Akt. Treatment with curcumin may suppress NOX5 expression in cancer cells and enhance sensitivity to cisplatin treatment. In a xenograft model, a combined regimen of cisplatin with low-dose curcumin significantly reduced malignant tumor growth. These data demonstrate that curcumin has a chemosensitizing effect on cisplatin-resistant epithelial cancer types. Therefore, the use of curcumin in addition to a cisplatin-based treatment regimen may improve treatment outcomes in human patients with epithelial cancer.