Riboflavin as adjuvant with cisplatin: study in mouse skin cancer model

Cisplatin used in treatment of solid tumor induces oxidative stress which leads to hepatotoxicity and nephrotoxicity. New strategies are therefore needed to combat toxicity and optimize its therapeutic potential. Riboflavin (VitaminB2) under photoillumination works as an anti proliferative agent and induces apoptosis. These properties of riboflavin have been exploited to mitigate cisplatin induced toxicities. 9,10-dimethylbenz(a)anthracene /12-O-tetradecanoylphorbol-13-acetate  were used to induce skin tumor in Swiss albino mice. The tumor induced mice were treated with cisplatin, riboflavin as well as their combination under photo illumination. In comparison to tumor control group the cisplatin and riboflavin treated groups showed a compromised level of antioxidant enzymes, functional markers and a higher degree of lipid peroxidation. However these parameters tended towards normal in the combination treated group. The results from histopathology indicate that apoptosis was favored mode of cell death and that necrosis was reduced in combination treated groups. Our findings indicate that combination of cisplatin with riboflavin under photo illumination synergizes its anti cancer activity towards cancer cells and attenuates the cisplatin induced toxicities.

Overexpression of ROCK1 and ROCK2 inhibits human laryngeal squamous cell carcinoma

Rho-associated coiled-coil containing protein kinase (ROCK) over-expression has been implicated in the progression of many tumor types. The aim of this study was to explore the roles of ROCK1 and ROCK2 in human laryngeal squamous cell carcinoma (LSCC). ROCK1 and ROCK2 expression levels were examined in 50 cases of human LSCC samples by immunohistochemistry. Effects of ROCK1 and ROCK2 on LSCC cell proliferation and motility were investigated in the presence of the ROCK inhibitor Y-27632. The results showed that ROCK1 expression was positively correlated with tumor size and lymph node metastasis (P < 0.05); ROCK2 positively correlated with tumor size (P < 0.05). Inhibition of ROCK1 and ROCK2 by Y-27632 significantly inhibits proliferation, migration, and invasion of LSCC cells. Our data indicate that expression of ROCK1 and ROCK2 are closely associated with tumor growth and lymph node metastasis of LSCC. Thus, these two ROCK isoforms may be useful as molecular makers for LSCC diagnosis and may be useful therapeutic targets as well.

SIRT6 promotes COX-2 expression and acts as an oncogene in skin cancer

SIRT6 is a SIR2 family member that regulates multiple molecular pathways involved in metabolism, genomic stability, and aging. It has been proposed previously that SIRT6 is a tumor suppressor in cancer. Here, we challenge this concept by presenting evidence that skin-specific deletion of SIRT6 in the mouse inhibits skin tumorigenesis. SIRT6 promoted expression of COX-2 by repressing AMPK signaling, thereby increasing cell proliferation and survival in the skin epidermis. SIRT6 expression in skin keratinocytes was increased by exposure to UVB light through activation of the AKT pathway. Clinically, we found that SIRT6 was upregulated in human skin squamous cell carcinoma. Taken together, our results provide evidence that SIRT6 functions as an oncogene in the epidermis and suggest greater complexity to its role in epithelial carcinogenesis.

Afatinib versus placebo as adjuvant therapy after chemoradiation in a double-blind, phase III study (LUX-Head & Neck 2) in patients with primary unresected, clinically intermediate-to-high-risk head and neck cancer: study protocol for a randomized controlled trial

BACKGROUND

Over 50% of patients with head and neck squamous cell carcinoma (HNSCC) present with locoregionally advanced disease. Those at intermediate-to-high risk of recurrence after definitive therapy exhibit advanced disease based on tumour size or lymph node involvement, non-oropharynx primary sites, human papillomavirus (HPV)-negative oropharyngeal cancer, or HPV-positive oropharynx cancer with smoking history (>10-pack-years). Non-surgical approaches include concurrent chemoradiotherapy, induction chemotherapy followed by definitive radiotherapy or chemoradiotherapy, or radiotherapy alone. Following locoregional therapies (including surgical salvage of residual cervical nodes), no standard intervention exists. Overexpression of epidermal growth factor receptor (EGFR), an ErbB family member, is associated with poor prognosis in HNSCC. EGFR-targeted cetuximab is the only targeted therapy that impacts overall survival and is approved for HNSCC in the USA or Europe. However, resistance often occurs, and new approaches, such as targeting multiple ErbB family members, may be required. Afatinib, an irreversible ErbB family blocker, demonstrated antiproliferative activity in preclinical models and comparable clinical efficacy with cetuximab in a randomized phase II trial in recurrent or metastatic HNSCC. LUX-Head & Neck 2, a phase III study, will assess adjuvant afatinib versus placebo following chemoradiotherapy in primary unresected locoregionally advanced intermediate-to-high-risk HNSCC.

METHODS/DESIGN

Patients with primary unresected locoregionally advanced HNSCC, in good clinical condition with unfavourable risk of recurrence, and no evidence of disease after chemoradiotherapy will be randomized 2:1 to oral once-daily afatinib (40 mg starting dose) or placebo. As HPV status will not be determined for eligibility, unfavourable risk is defined as non-oropharynx primary site or oropharynx cancer in patients with a smoking history (>10 pack-years). Treatment will continue for 18 months or until recurrence or unacceptable adverse events occur. The primary endpoint measure is duration of disease-free survival; secondary endpoint measures are disease-free survival rate at 2 years, overall survival, health-related quality of life and safety.

DISCUSSION

Given the unmet need in the adjuvant treatment of intermediate-to-high-risk HNSCC patients, it is expected that LUX-Head & Neck 2 will provide new insights into treatment in this setting and might demonstrate the ability of afatinib to significantly improve disease-free survival, compared with placebo.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01345669.

Topo2A as a prognostic biomarker for patients with resectable esophageal squamous cell carcinomas

Topoisomerase 2α (Topo2A) is a key enzyme in replication. It functions as a cell proliferation and cell cycle-specific marker and it is identified mainly in the interphase nuclei of proliferating cells. Many studies have shown that Topo2A protein expression is up-regulated in various cancers including esophageal cancer. However, to date, no studies have adequately addressed the prognostic value of Topo2A in patients with resectable esophageal squamous cell carcinoma (ESCC). Therefore, we conducted a large-scale retrospective study investigating the expression of Topo2A and the clinicopathological characteristics or prognosis of ESCC patients. Eight hundred and twenty-nine specimens of ESCC from patients who underwent complete esophageal cancer resection were evaluated using an immunohistochemical assay. Among them, 404 (48.7 %) cases with a score >2 were determined to be positive for Topo2A expression. Topo2A overexpression was significantly associated with poorer differentiation (P = 0.007) and perineural invasion (P = 0.046). The median progression-free survival (PFS) of 319 patients with Topo2A-positive expression and 336 patients with Topo2A-negative expression was 19.5 and 26.5 months, respectively (P = 0.000). The overall survival (OS) in patients with and without Topo2A expression was 34.0 and 44.5 months, respectively (P = 0.002). In the multivariate analysis, Topo2A overexpression was identified as an independent prognostic factor for PFS (P = 0.001) and OS (P = 0.009). We determined that Topo2A overexpression was not only associated with poorer differentiation and perineural invasion, but it could also act as an independent risk factor for ESCC.

High level of plasma matrix metalloproteinase-11 is associated with clinicopathological characteristics in patients with oral squamous cell carcinoma

Background

Matrix metalloproteinase-11 (MMP-11) is reported to be overexpressed in several cancers and may contribute to tumorigenesis. The current study investigated the association between the clinicopathological characteristics and plasma level of MMP-11 in oral squamous cell carcinoma (OSCC) patients.

Methodology and Principal Findings

The plasma MMP-11 concentration was determined by ELISA on 330 male OSCC patients. In addition, the metastatic effects of the MMP-11 knockdown on the oral cancer cells were investigated by cell migration assay. Our results showed that the plasma MMP-11 levels were significantly higher in patients with advanced T status (p = 0.001), lymph node metastasis (p = 0.006) and higher TNM stages (p<0.001). Moreover, treatment with the MMP-11 shRNA exerted an inhibitory effect on migration in SCC9 oral cancer cells.

Conclusion

Our study showed that plasma level of MMP-11 may be useful for assessment of the disease progression, especially lymph node metastasis, in patients with OSCC.

[Expression and significance of DNA-dependent protein kinase in human laryngeal squamous cell carcinoma]

OBJECTIVE

To study the expression of DNA-dependent protein kinase (DNA-PK) in human laryngeal squamous cell carcinoma (LSCC) and normal laryngeal mucosa (NLM), and to analysize the relationship between the expression and the clinicopathologic parameters of LSCC.

METHOD

Immunohistochemical technique (Envision) was used to detect the expression of DNA-PK in 64 cases of LSCC and 15 cases of NLM. To investigate an investigation was conducted on the relationship between the expression and clinico-pathological features of LSCC.

RESULT

DNA-PK was lowly expressed in NLM and highly expressed in LSCC,the positive rate of DNA-PK expression was 26.67% (4/15), 78.13% (50/64), respectively, and there was significant different difference between the two groups (P < 0.05). Its expression was correlated with the level of histodifferentiation (P < 0.05), but not with TNM stages and neck lymph node metastasis (P > 0.05).

CONCLUSION

DNA-PK may be involved in disease development of LSCC.

[Key enzymes of degradation and angiogenesis as a factors of tumor progression in squamous cell carcinoma of the cervix]

A key role in tumor progression play two processes--the destruction and angiogenesis. Matrix metalloproteases (MMPs) play a leading role during tissue degradation. Tissue collagenase--MMP-1 and MT1-MMP hydrolyze fibrillar collagens, which are the basis of connective tissue matrix, and ensure the development of an invasive process. Gelatinase A and B (MMP-2 and MMP-9) hydrolyze collagen type IV, which is the basis of the basal membrane, and facilitate the development of metastasis. Endogenous tissue inhibitors TIMP-1 and TIMP-2 are involved in the regulation of MMP expression and activity. It has been established that MMP-9 release vascular endothelial growth factor (VEGF) associated with the STM--the primary inductor angiogenesis. Angiotensin-converting enzyme (ACE) participates in the induction of VEGF synthesis. ACE--a key enzyme of the renin-angiotensin system, forms angiotensin II, which interactes with the receptor ATIR and induces VEGF synthesis, as well as stimulates endothelial cell proliferation. Our experimental studies devoted to the study of particularity expression of key enzymes of destruction and angiogenesis in squamous cell carcinoma of the cervix (SCC). It was studied: MMP-1, MT1-MMP, MMP-2 and MMP-9 and their endogenous regulators: TIMP-1, TIMP-2, and as well as ACE. Work was performed on clinical specimens containing the tumor tissue, taking into account the presence or absence of metastasis to regional lymph nodes and the specimens of adjacent morphologically normal tissue. It was shown that the increase of MMP-1, MT1-MMP and MMP-9 expression and low of TIMP-1 and TIMP-2 expression makes the main contribution to the destructive (invasive) potential of SCC. The change of MMP-2 expression is not so significant and it is less influenced to the destructive potential. It was shown dramatic increasing of MMP-1 and MMP-9 activity in metastasizing tumor tissue ACE activity in a tumor in most of the samples was higher than the activity in normal tissues. It was established that the expression of key enzymes degradation and angiogenesis occurs not only in tumor but also in normal tissues. Data are important for understanding the mechanisms of tumor progression and have prognostic value and may affect the therapeutic strategy for patients.

Matrix-metalloproteinases in head and neck carcinoma-cancer genome atlas analysis and fluorescence imaging in mice

OBJECTIVE

(1) Obtain matrix-metalloproteinase (MMP) expression profiles for head and neck squamous cell carcinoma (HNSCC) specimens from the Cancer Genomic Atlas (TCGA). (2) Demonstrate HNSCC imaging using MMP-cleavable, fluorescently labeled ratiometric activatable cell-penetrating peptide (RACPP).

STUDY DESIGN

Retrospective human cohort study; prospective animal study.

SETTING

Translational research laboratory.

SUBJECTS AND METHODS

Patient clinical data and mRNA expression levels of MMP genes were downloaded from TCGA data portal. RACPP provides complementary ratiometric fluorescent contrast (increased Cy5 and decreased Cy7 intensities) when cleaved by MMP2/9. HNSCC-tumor bearing mice were imaged in vivo after RACPP injection. Histology was evaluated by a pathologist blinded to experimental conditions. Zymography confirmed MMP-2/9 activity in xenografts. RACPP was applied to homogenized human HNSCC specimens, and ratiometric fluorescent signal was measured on a microplate reader for ex vivo analysis.

RESULTS

Expression of multiple MMPs including MMP2/9 is greater in patient HNSCC tumors than matched control tissue. In patients with human papilloma virus positive (HPV+) tumors, higher MMP2 and MMP14 expression correlates with worse 5-year survival. Orthotopic tongue HNSCC xenografts showed excellent ratiometric fluorescent labeling with MMP2/9-cleavable RACPP (sensitivity = 95.4%, specificity = 95.0%). Fluorescence ratios were greater in areas of higher tumor burden (P < .03), which is useful for intraoperative margin assessment. Ex vivo, human HNSCC specimens showed greater cleavage of RACPP when compared to control tissue (P = .009).

CONCLUSIONS

Human HNSCC tumors show increased mRNA expression of multiple MMPs including MMP2/9. We used RACPP, a ratiometric fluorescence assay of MMP2/9 activity, to show improved occult tumor identification and margin clearance. Ex vivo assays using RACPP in biopsy specimens may identify patients who will benefit from intraoperative RACPP use.

Immunosuppression in cervical cancer with special reference to arginase activity

INTRODUCTION

Cervical cancer is characterized by an immunosuppressive microenvironment and a Th2-type cytokine profile. Expression of arginase (ASE), the enzyme that converts L-arginine into L-ornithine and urea, is stimulated by Th2-type cytokines.

OBJECTIVE

To assess the association of ASE activity and L-Arg metabolism products with cervical cancer.

METHODS

Sera of 87 and 41 women with histologically confirmed by colposcopy-directed biopsy SCC and CIN3 respectively and 79 with normal cytology or Low-Grade Squamous Intraepithelial Lesion (LSIL), were evaluated. Cytokines were measured using Milliplex Human cytokine/chemokine kit. Arginase (ASE) activity was determined using an enzymatic assay. Levels of L-arginine, L-ornithine, putrescine and spermine were determined by HPLC.

RESULTS

Significantly higher levels of ASE activity were observed in women with CIN3 (age-adjusted OR: 24.3; 95%CI: 3.82-155) and SCC (AOR: 9.8; 95%CI: 2.34-40.8). As expected, possibly due to high levels of ASE activity, higher levels of l-Arg were negatively associated with CIN3 (AOR: 0.03; 95%CI: 0.004-0.19) and SSC (AOR: 0.06; 95%CI: 0.02-0.24). Consistent with the role of ASE in the conversion of L-arginine to L-ornithine and polyamine production therefrom, women with cervical cancer had higher levels of spermine and putrescine. A correlation analysis revealed a significant albeit weak relationship between high levels of IL-10 and high levels of ASE (Pearson r=0.32, p-value=0.003) in women with cervical cancer.

CONCLUSION

This study indicates that ASE activity and L-Arg degradation mechanisms of immunosuppression are present in cervical cancer. The results foster research in the design of possible strategies to inhibit ASE activity for therapy of cervical cancer.

Nitric oxide synthase evaluation in oral precancerous and cancerous lesions

Nitric Oxide (NO) has been linked to several cardiovascular, neurological and immunological physiological and pathological functions. Several studies have shown that the eNOS, nNOS and iNOS effects on cancer cell growth and proliferation are related to the upregulation of the Wnt pathway and have a central role during metastasis development. Recent studies suggest that cancer cells undergo metabolic reprogramming, which drives cancer cell growth and progression. The aim of this study was to observe the NOS activity in the pathogenesis of oral precancerous and cancerous lesions. The results showed changes in eNOS activity levels, which increased from healthy oral mucosa to oral squamous cell carcinoma SCC, through different dysplasia levels. The iNOS activity levels increased in precancerous lesions compared to healthy mucosa, where iNOS was absent, while it decreased in SCC lesions. Moreover, a gradual increase of nNOS activity together with the progression of the lesions was also found. These results may suggest how NO could play a critical role during pathogenesis, growth and development of precancerous lesions to cancer degeneration.

Identification of a novel lysyl oxidase-like 2 alternative splicing isoform, LOXL2 Δe13, in esophageal squamous cell carcinoma

Lysyl oxidase-like 2 (LOXL2) participates in every stage of cancer progression and promotes invasion and metastasis. In this study, we identified a novel alternative splicing isoform of LOXL2, namely LOXL2 Δe13, which lacked exon 13. Deletion of exon 13 caused an open reading frame shift and produced a truncated protein. LOXL2 Δe13 was expressed ubiquitously in cell lines and tissues and was mainly localized to the cytoplasm. Although it showed impaired deamination enzymatic activity compared with full-length LOXL2, LOXL2 Δe13 promoted the cell mobility and invasion of esophageal squamous cell carcinoma (ESCC) cells to greater degrees. In further research on the mechanisms, gene expression profiling and signaling pathway analysis revealed that LOXL2 Δe13 induced the expression of MAPK8 without affecting the FAK, AKT, and ERK signaling pathways. RNAi-mediated knockdown of MAPK8 could block the cell migration promoted by LOXL2De13, but it had little effect on that of full-length LOXL2. Our data suggest that LOXL2 Δe13 modulates the effects of cancer cell migration and invasion through a different mechanism from that of full-length LOXL2 and that it may play a very important role in tumor carcinogenesis and progression.

microRNA-195-Cdc42 axis acts as a prognostic factor of esophageal squamous cell carcinoma

BACKGROUND AND PURPOSE

Previous studies observed the downregulation of microRNA (miR)-195 in esophageal squamous cell carcinoma (ESCC) tissues, confirmed cell division cycle 42 (Cdc42) as one target gene of miR-195, and demonstrated that miR-195 may act as a tumor suppressor in ESCC by regulating Cdc42 expression. This study aimed to explore the association of miR-195 and Cdc42 combined expression with clinicopathologic factors and prognosis.

METHODS

Expression of miR-195 and Cdc42 mRNA in 98 pairs of ESCC and paracancerous tissues were detected using real-time quantitative RT-PCR.

RESULTS

miR-195 downregulation and Cdc42 upregulation were both prevalent in ESCC tissues, and negatively correlated with each other. In addition, miR-195 expression negatively correlated with TNM stage (P=0.008) and lymphatic metastasis (P=0.022), while Cdc42 expression positively correlated with TNM stage (P=0.011) and tumor differentiation (P=0.024). Moreover, combined expression of miR-195 and Cdc42 (miR-195/Cdc42) was found to be prognostic indicators for progression-free survival and overall survival of ESCC patients both in univariate and multivariate analyses.

CONCLUSION

The main findings of this study indicate the involvement of miR-195-Cdc42 axis in the progression of ESCC and suggest that the combined aberrant expression of miR-195 and Cdc42 mRNA can serve as a promising unfavorable prognostic biomarker in ESCC.

Curcumin inhibits oral squamous cell carcinoma proliferation and invasion via EGFR signaling pathways

Epidermal growth factor receptor (EGFR) is an effective molecular target of anti-cancer therapies. Curcumin is known to inhibit growth, invasion and metastasis by downregulating EGFR expression in some cancer cells. However, the mechanism underlying the effect of curcumin in human oral squamous cell carcinoma (OSCC) remains unclear. In this study, we investigated the efficacy of curcumin on proliferation and invasion in SCC-25 cell line. We also explored the effect of curcumin on the activition of EGFR and its downstream signaling molecules Akt, ERK1/2 and STAT3. Furthermore, we examined the inhibition effect of curcumin on EGF-induced EGFR phosphorylation and SCC-25 cells invasion. Our results showed that curcumin inhibited SCC-25 cells proliferation and induced G2/M phase arrest in a dose-dependent manner. Curcumin also inhibited SCC-25 cells invasion and downregulated MMP-2, MMP-9, uPA and uPAR expression. We further revealed that curcumin regulated the p-EGFR and EGFR downstream signaling molecules including Akt, ERK1/2 and STAT3. Finally, our data showed that crucumin reduced the EGF-induced phosphorylation of EGFR and suppressed EGF-triggered SCC-25 cells invasion. Taken together, our results suggest that curcumin reduced SCC-25 cells proliferation and invasion through inhibiting the phosphorylation of EGFR and EGFR downstream signaling molecules Akt, ERK1/2 and STAT3.

Expression patterns of three regulation enzymes in glycolysis in esophageal squamous cell carcinoma: association with survival

Enhanced glycolysis is a common trait of many types of human cancers. This study was to detect the expression pattern of three regulatory enzymes during glycolysis in esophageal squamous cell carcinoma (ESCC) and to investigate their correlation with patients' outcome based on banked pathology material. A total of 141 surgically resected specimens of primary ESCC patients without prior treatments were retrospectively recruited from the First Affiliated Hospital of Wenzhou Medical College Hospital from 2007 to 2009. Expression of HK1, PFKB, and PKM2 in ESCC specimens was analyzed by immunohistochemical staining and Western blotting analysis. HK1-shRNA was used to knock down HK1 expression in ESCC cells, and the functional significance was assessed by CCK8 assay. It was found that the expression of two glycolytic enzymes, HK1 and PKM2, was associated with disease progression, invasion, and poor survival of patients with ESCC. Silence of HK1-inhibited cell proliferation in vitro and suppressed phospho-S6 kinase expression. Our findings suggest that activation of key enzymes in glycolysis might serve as potential therapeutic targets and/or prognostic factors for patients with ESCC.

[Relation between carbonic anhydrase IX serum level, hypoxia and radiation resistance of head and neck cancers]

BACKGROUND

Hypoxia of locally advanced head and neck cancers is one of the main causes of their radiation resistance that presents clinically as a persistence of residual tumor disease after radiation therapy. Therefore, detection of tumor hypoxia could be an important predictor of treatment efficacy. Carbonic anhydrase IX (CA IX) is a protein, coded by a homonymous gene, the expression of which increases in tumor tissues at hypoxic conditions. Hence, CA IX represents an endogenic marker of tumor hypoxia, identifiable in tumor tissues, and its soluble extracellular domain can also be detected in body fluids of the patient. The primary endpoint of this study was to explore whether a correlation exists between CA IX serum level and the residual tumor disease after therapy. The secondary endpoint was to find out how the serum concentration of CA IX changes during the course of fractionated radiation therapy.

MATERIALS AND METHODS

The presented prospective monocentric clinical study evaluated a population of 30 patients with locally advanced squamous cell head and neck cancers, treated by radiation therapy or concurrent chemo radiation therapy with a curative intent. The serum concentration of the soluble form of CA IX was examined from a venous blood sample, using sandwich enzyme linked immunosorbent assay (ELISA). The blood samples were obtained before the treatment initiation, in the middle of radiation therapy, at the time of finishing radiation therapy and six weeks after the treatment completion.

RESULTS

We found a substantial variability in the CA IX levels measured in the examined population, ranging 0- 1,696 pg/ ml. We found no significant changes in the mean value of CA IX concentration during the course of radiation therapy and after the treatment completion. In 11 patients (36.7%), the treatment resulted in complete remission of the disease. In these patients, lower average pretreatment levels of CA IX were noted when compared to patients with persistence of residual tumor disease (37.57 vs 77.47; p = 0.154).

CONCLUSION

The results indicate that serum level of CA IX in patients with locally advanced head and neck cancers does not change significantly during the course of fractionated radiation therapy. The relation between CA IX serum level and residual tumor disease after radiation therapy requires verification on a larger population of patients.

[Prognostic significance of NADPH quinine oxidoreductase 1 overexpression in head and neck squamous cell carcinoma]

OBJECTIVE

To investigate the significance of NADPH quinine oxidoreductase 1 (NQO1) protein overexpression on prognostic evaluation of head and neck squamous cell carcinoma (HNSCC).

METHODS

NQO1 protein was detected in 162 of HNSCC, 45 cases of adjacent nontumor tissues and 26 samples of normal head and neck epithelia using EnVision immunohistochemical. Correlation between NQO1 overexpression and patients prognosis was also analyzed.

RESULTS

The positive rate and strongly positive rate of NQO1 protein were 84.0% (136/162) and 69.8% (113/162) in HNSCC, respectively, and both of which were significantly higher than either those in adjacent nontumor tissues and normal head and neck epithelia (both P < 0.01). NQO1 expression was significantly correlated with the clinical stage, pT and chemoradiotherapy of HNSCC (P < 0.01). Kaplan-Meier survival analysis showed that overall survival and disease-free survival rates were significantly higher in HNSCC patients with high level NQO1 expression than that those with low level of NQO1 expression (Log-rank = 6.625 , P = 0.010;Log-rank = 6.234 , P = 0.013). Additional analysis by Cox proportional hazard regression model showed that high level of NQO1 expression was an independent hazard predictor for overall survival of patients with HNSCC (Wald = 6.626, P = 0.008).

CONCLUSIONS

NQO1 expression level is closely correlated with the progression and prognosis of patients with HNSCC. High level of NQO1 expression may be used as an important indicator for patients with poor prognostic HNSCC.

The rational design of specific peptide inhibitor against p38α MAPK at allosteric-site: a therapeutic modality for HNSCC

p38α is a significant target for drug designing against cancer. The overproduction of p38α MAPK promotes tumorigenesis in head and neck squamous cell carcinoma (HNSCC). The ATP binding and an allosteric site referred as DFG are the key sites of the p38α mitogen activated protein kinase (MAPK) exploited for the design of inhibitors. This study demonstrated design of peptide inhibitor on the basis of allosteric site using Glide molecular docking software and the biochemical analysis of the best modeled peptide. The best fitted tetrapeptide (FWCS) in the allosteric site inhibited the pure recombinant and serum p38α of HNSCC patients by 74 and 72%, respectively. The potency of the peptide was demonstrated by its IC50 (4.6 nM) and KD (3.41×10-10 M) values, determined by ELISA and by surface plasmon resonance (SPR) technology, respectively. The cell viability of oral cancer i.e. KB cell line was reduced in dose dependent manner by 60 and 97% by the treatment of peptide and the IC50 was 600 and 210 µM after 24 and 72 h incubation, respectively. Our result provides an insight for the development of a proficient small peptide as a promising anticancer agent targeting DFG site of p38α kinase.

Coordinated expression of cyclin-dependent kinase-4 and its regulators in human oral tumors

BACKGROUND/AIM

While aberrant expression of cyclin-dependent kinase-4 (CDK4) has been found in squamous cell carcinoma of the head and neck (SCCHN), the associations between CDK4 and its regulators, namely, cyclin D1, cyclin E, gankyrin, SEI1, and BMI1 in gene expression remain to be explored. Herein we investigated the mRNA profiles of these oncogenes and their interrelations in different oral lesion tissues.

MATERIALS AND METHODS

Thirty SCCHN specimens and patient-matched high at-risk mucosa (HARM) and 16 healthy control specimens were subjected to quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analyses.

RESULTS

The mRNA levels of CDK4, cyclin D1, gankyrin, SEI1, BMI1 were significantly elevated in both HARM and SCCHN (in comparison with control specimens), and statistically significant correlations were found among these markers in gene expression.

CONCLUSION

Up-regulation of CDK4 and its regulators takes place in oral cancer progression in a coordinate manner, and HARM and SCCHN share a similar molecular signature within the CDK4-pRB pathway.

APOBEC-mediated cytosine deamination links PIK3CA helical domain mutations to human papillomavirus-driven tumor development

APOBEC3B cytosine deaminase activity has recently emerged as a significant mutagenic factor in human cancer. APOBEC activity is induced in virally infected cells, and APOBEC signature mutations occur at high frequency in cervical cancers (CESC), over 99% of which are caused by human papillomavirus (HPV). We tested whether APOBEC-mediated mutagenesis is particularly important in HPV-associated tumors by comparing the exomes of HPV+ and HPV- head and neck squamous cell carcinomas (HNSCCs) sequenced by The Cancer Genome Atlas project. As expected, HPV- HNSCC displays a smoking-associated mutational signature, whereas our data suggest that reduced exposure to exogenous carcinogens in HPV+ HNSCC creates a selective pressure that favors emergence of tumors with APOBEC-mediated driver mutations. Finally, we provide evidence that APOBEC activity is responsible for the generation of helical domain hot spot mutations in the PIK3CA gene across multiple cancers. Our findings implicate APOBEC activity as a key driver of PIK3CA mutagenesis and HPV-induced transformation.

Cell-cycle distribution and Thymidilate Synthatase (TS) expression correlate with 5-FU resistance in head and neck carcinoma cells

BACKGROUND

Acquired chemoresistance to 5-fluorouracil (5-FU) remains one of the obstacles for the success of 5-FU-based cancer chemotherapy, and some molecular mechanisms of acquired 5-FU resistance are still unknown. The main action of 5-FU is the suppression of DNA replication by inhibiting Thymidylate Synthase (TS).

MATERIALS AND METHODS

We analyzed 5-FU resistance mechanisms using the head and neck squamous cell carcinoma cell lines, UM-SCC-23, and two different resistant cell lines, UM-SCC-23/WR and UM-SCC-23/MR, which were procured from UM-SCC-23 cells. To acquire resistance, the two cells underwent repeated treatment of 5-FU with different durations and frequency. We determined differences in the cell-cycle distribution and the expression of TS proteins in the three cell lines. Moreover, cell-cycle distribution in cells which acquired resistance after 5-FU treatment, was compared to that of parental cells, using flow cytometric analysis.

RESULTS

There was a remarkable increase in TS protein expression levels in UM-SCC-23/WR following 5-FU treatment. S-phase cells of UM-SCC-23 and UM-SCC-23/WR cells were immediately increased after treatment with 5-FU, whereas UM-SCC-23/MR were accumulated to the S-phase slightly later.

CONCLUSION

The cell-cycle perturbation or elevation of TS protein expression may be involved in acquired 5-FU resistance and identifies 5-FU resistance mechanisms in the two different 5-FU treatment regimens.

Phosphorylation of multifunctional nucleolar protein nucleophosmin (NPM1) by aurora kinase B is critical for mitotic progression

The functional association of NPM1 with Aurora kinases is well documented. Surprisingly, although NPM1 is a well characterized phosphoprotein, it is unknown whether it is a substrate of Aurora kinases. We have found that Aurora kinases A and B can phosphorylate NPM1 at a single serine residue, Ser125, in vitro and in vivo. Phosphorylated-S125-NPM1 (pS125-NPM1) localizes to the midbody region during late cytokinesis where it colocalizes with Aurora B. The overexpression of mutant (S125A) NPM1 resulted in the deregulation of centrosome duplication and mitotic defects possibly due to cytokinesis failure. These data suggest that Aurora kinase B-mediated phosphorylation of NPM1 plays a critical role during mitosis, which could have wider implications in oncogenesis.

Diagnostic value of next-generation sequencing in an unusual sphenoid tumor

Extraordinary advancements in sequencing technology have made what was once a decade-long multi-institutional endeavor into a methodology with the potential for practical use in a clinical setting. We therefore set out to examine the clinical value of next-generation sequencing by enrolling patients with incurable or ambiguous tumors into the Personalized OncoGenomics initiative at the British Columbia Cancer Agency whereby whole genome and transcriptome analyses of tumor/normal tissue pairs are completed with the ultimate goal of directing therapeutics. First, we established that the sequencing, analysis, and communication with oncologists could be completed in less than 5 weeks. Second, we found that cancer diagnostics is an area that can greatly benefit from the comprehensiveness of a whole genome analysis. Here, we present a scenario in which a metastasized sphenoid mass, which was initially thought of as an undifferentiated squamous cell carcinoma, was rediagnosed as an SMARCB1-negative rhabdoid tumor based on the newly acquired finding of homozygous SMARCB1 deletion. The new diagnosis led to a change in chemotherapy and a complete nodal response in the patient. This study also provides additional insight into the mutational landscape of an adult SMARCB1-negative tumor that has not been explored at a whole genome and transcriptome level.

Association between esophageal cancer risk and EPHX1 polymorphisms: A meta-analysis

AIM: To summarize the relationship between p.Tyr113His and p.His139Arg polymorphisms in microsomal epoxide hydrolase (EPHX1) and risk for esophageal cancer (EC).

METHODS: The MEDLINE/PubMed and EMBASE databases were searched for studies of the association between EPHX1 polymorphisms and EC risk that were published from the database inception date to April 2013. A total of seven case-control studies, including seven on p.Tyr113His (cases, n = 1118; controls, n = 1823) and six on p.His139Arg (cases, n = 861; controls, n = 1571), were included in the meta-analysis. After data extraction by two investigators working independently, the meta-analyses were carried out with STATA 11.0 software. Pooled odds ratios and 95%CI were calculated using a fixed-effects model or a random-effects model, as appropriate.

RESULTS: The pooled EPHX1 p.Tyr113His polymorphism data showed no significant association with EC in any of the genetic models (OR = 1.00, 95%CI: 0.70-1.48 for Tyr/His vs Tyr/Tyr; OR = 1.10, 95%CI: 0.77-1.57 for His/His vs Tyr/Tyr; OR = 1.06, 95%CI: 0.75-1.49 for a dominant model; OR = 1.09, 95%CI: 0.89-1.34 for a recessive model). Similar results were obtained from the p.His139Arg polymorphism analysis (Arg/His vs His/His: OR = 1.02, 95%CI: 0.84-1.23; Arg/Arg vs His/His: OR = 0.96, 95%CI: 0.60-1.54; OR = 1.03, 95%CI: 0.78-1.37 for the dominant model; OR = 0.97, 95%CI: 0.61-1.56 for the recessive model). Subgroup analyses for ethnicity, subtype of EC, and source of controls (population-based or hospital-based) showed trends that were consistent with the pooled analysis (reported above), with no significant associations found.

CONCLUSION: This meta-analysis suggests that the p.Tyr113His and p.His139Arg polymorphisms in EPHX1 may not be associated with EC development.

FLT1 kinase is a mediator of radioresistance and survival in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the fifth most common malignancy worldwide, responsible for approximately half a million new cases every year. The treatment of this disease is challenging and characterised by high rates of therapy failure and toxicity, stressing the need for new innovative treatment strategies.

MATERIAL AND METHODS

In this study we performed a shRNAmir-based screen on HNSCC cells with the aim to identify tyrosine kinases that are mediating radiotherapy resistance.

RESULTS

The receptor tyrosine kinase FLT1 (VEGFR1) was identified as an important driver of cell survival and radioresistance. We show that FLT1 is phosphorylated in HNSCC cells, and document autocrine production of FLT1 ligands VEGFA and VEGFB, leading to receptor activation. Immunohistochemistry on HNSCC patient samples demonstrated FLT1 and VEGFA to be uniformly expressed. Interestingly, FLT1 was selectively overexpressed in tumour tissue as compared to non-cancerous epithelium. Remarkably, we found only membrane permeable FLT1 kinase inhibitors to be effective, which was in agreement with the intracellular localisation of FLT1.

DISCUSSION AND CONCLUSION

Taken together, we document expression of FLT1 in HNSCC and demonstrate this kinase to modulate radioresistance and cancer cell survival. Given the fact that FLT1 kinase is selectively upregulated in tumour tissue and that its kinase function seems expendable for normal life and development, this kinase holds great promise as a new potential therapeutic target.