Molecular changes in the multistage pathogenesis of head and neck cancer

Evaluation of co‑inhibition of ErbB family kinases and PI3K for HPV‑negative head and neck squamous cell carcinoma

The ErbB/HER family of protein‑tyrosine kinases and PI3K represent crucial targets in the treatment of head and neck squamous cell carcinoma (HNSCC). A combination therapy of afatinib (ErbB inhibitor) and copanlisib (PI3K inhibitor), both Food and Drug Administration‑approved kinase inhibitors, can suppress the growth of human papillomavirus (HPV)‑positive HNSCC. The current study further evaluated the efficacy and clinical potential of this combination therapy for the treatment of HPV‑negative HNSCC in vitro and in vivo. Sulforhodamine B cell viability assay and Annexin V/propidium iodide staining demonstrated that this combination treatment markedly enhanced inhibition of cell viability and reduced cell survival when compared with treatment with either inhibitor alone in two HPV‑negative HNSCC cell lines. Notably, this combination also led to significant inhibition of xenograft tumor growth in mice, without any apparent effects on body weight. Western blot analysis found that copanlisib alone effectively blocked PI3K/Akt signaling but caused upregulation of HER2 and HER3 phosphorylation, as reported in other types of cancer. However, the combination of copanlisib and afatinib completely blocked phosphorylation of the ErbB family (including HER3) and Akt, while also increasing apoptosis. In conclusion, these results suggested that co‑targeting the ErbB family kinases and PI3K using a combination treatment of afatinib and copanlisib may have clinical potential for patients with HPV‑negative HNSCC.

Ribosomal Dysregulation in Metastatic Laryngeal Squamous Cell Carcinoma: Proteomic Insights and CX-5461's Therapeutic Promise

One of the main barriers to the successful treatment of laryngeal squamous cell carcinoma (LSCC) is postoperative progression, primarily due to tumor cell metastasis. To systematically investigate the molecular characteristics and potential mechanisms underlying the metastasis in laryngeal cancer, we carried out a TMT-based proteomic analysis of both cancerous and adjacent non-cancerous tissues from 10 LSCC patients with lymph node metastasis (LNM) and 10 without. A total of 5545 proteins were quantified across all samples. We identified 57 proteins that were downregulated in LSCC with LNM, which were enriched in cell adhesion pathways, and 69 upregulated proteins predominantly enriched in protein production pathways. Importantly, our data revealed a strong correlation between increased ribosomal activity and the presence of LNM, as 18 ribosomal subunit proteins were found to be upregulated, with RPS10 and RPL24 being the most significantly overexpressed. The potential of ribosomal proteins, including RPS10 and RPL24, as biomarkers for LSCC with LNM was confirmed in external validation samples (six with LNM and six without LNM) using Western blotting and immunohistochemistry. Furthermore, we have confirmed that the RNA polymerase I inhibitor CX-5461, which impedes ribosome biogenesis in LSCC, also decreases the expression of RPS10, RPL24, and RPS26. In vitro experiments have revealed that CX-5461 moderately reduces cell viability, while it significantly inhibits the invasion and migration of LSCC cells. It can enhance the expression of the epithelial marker CDH1 and suppress the expression of the mesenchymal markers CDH2, VIM, and FN at a dose that does not affect cell viability. Our study broadens the scope of the proteomic data on laryngeal cancer and suggests that ribosome targeting could be a supplementary therapeutic strategy for metastatic LSCC.

Differential modulation of PI3K/Akt/mTOR activity by EGFR inhibitors: A rationale for co-targeting EGFR and PI3K in cisplatin-resistant HNSCC

PURPOSE

To find a new strategy to treat cisplatin-resistant head and neck squamous cell carcinoma (HNSCC), we investigated the effects of EGFR inhibitors on the PI3K/Akt/mTOR pathway and determined the efficacy of EGFR inhibitors in combination with PI3K inhibitors to suppress cell proliferation in cisplatin-resistant-HNSCC.

METHODS

The cisplatin-resistant HNSCC cell lines were treated with four FDA approved EGFR inhibitors, which included Gefitinb or Erlotinib alone, or in combination with the pan-PI3K inhibitor, BKM120. Phosphorylation and total protein levels of cells were assessed by Western blot analysis. Cell proliferation was examined by MTS assay. Apoptosis was analyzed by flow cytometry.

RESULTS

Cisplatin-resistant HNSCC cells were also resistant to EGFR inhibitors. However, a combination of EGFR inhibitors with PI3K inhibitor BKM120 dramatically improved the efficacy of EGFR inhibitors to inhibit cell proliferation and induce apoptosis. Furthermore, treatment with EGFR inhibitors differentially affected the phosphorylation of Akt and mTOR, which included partial inhibition, no inhibition, and induction. A combination of EGFR inhibitors and BKM120 completely blocked phosphorylation of EGFR, Akt, and S6K (an mTOR target).

CONCLUSION

Our data provided a rationale for EGFR inhibitors in combination with PI3K inhibitors to treat cisplatin-resistant HNSCC.

Correlation of Bony Invasion With Nodal Metastasis, Pattern of Invasion and Survival in Oral Squamous Cell Carcinoma: A Retrospective Analysis of 122 Primary Cases From Oral Cancer Centre of South India

Background Oral squamous cell carcinoma (OSCC) is considered to be the most common epithelial malignant neoplasm of the oral cavity. Despite advancements in diagnosis and therapeutics the clinical outcome of the disease has not improved much which may be attributed to tumor biology and heterogeneity. Bone invasion by cancer cells is currently staged as a moderately advanced disease. However, many low-grade carcinomas such as verrucous carcinoma and carcinoma cuniculatum show body invasion but less nodal metastases and better overall survival. The present study was orchestrated to analyze if bone invasion in OSCC has any impact on regional nodal metastases and survival. Materials and methods A total of 122 cases of OSCC who underwent excision and neck dissection were retrieved and included. These cases were then divided into two study groups. Group I comprised 56 OSCC cases with bone involvement and 66 cases with no bony involvement. The bone invasion was correlated with nodal metastases, survival and pattern of invasion. Statistical analysis was done using SPSS software (IBM Corp., Armonk, NY, USA). Results There was no statistically significant correlation between bone invasion with either nodal metastases or pattern of invasion, however, the worst pattern of invasion (WPOI)-4,5 showed a statistically higher incidence of nodal involvement in OSCC. No statistical difference was noted in overall survival between the two groups. Conclusion The worst pattern of invasion and not bone involvement, depicts nodal metastases in OSCC and thus, deserves consideration while staging and treatment planning.

Inferring early genetic progression in cancers with unobtainable premalignant disease

Analysis of premalignant tissue has identified the typical order of somatic events leading to invasive tumors in several cancer types. For other cancers, premalignant tissue is unobtainable, leaving genetic progression unknown. Here, we demonstrate how to infer progression from exome sequencing of primary tumors. Our computational method, PhylogicNDT, recapitulated the previous experimentally determined genetic progression of human papillomavirus-negative (HPV^-) head and neck squamous cell carcinoma (HNSCC). We then evaluated HPV⁺ HNSCC, which lacks premalignant tissue, and uncovered its previously unknown progression, identifying early drivers. We converted relative timing estimates of driver mutations and HPV integration to years before diagnosis based on a clock-like mutational signature. We associated the timing of transitions to aneuploidy with increased intratumor genetic heterogeneity and shorter overall survival. Our approach can establish previously unknown early genetic progression of cancers with unobtainable premalignant tissue, supporting development of experimental models and methods for early detection, interception and prognostication.

Upregulation of HOX genes promotes cell migration and proliferation in head and neck squamous cell carcinoma

BACKGROUND

Expression dysregulation of HOX homeobox genes has been observed in several cancers, including head and neck squamous cell carcinoma (HNSC). Although characterization of HOX gene roles in HNSC development has been reported, there is still a need to better understand their real contribution to tumorigenesis.

OBJECTIVE

The present study aimed to evaluate the contribution of the protein-coding HOX genes (HOXA10, HOXC9, HOXC10, and HOXC13) in cellular processes related to carcinogenesis and progression of the HNSC.

METHODS

Expression of HOX genes was analyzed in HNSC RNA-Seq data from The Cancer Genome Atlas (TCGA) and by RT-qPCR in different tumor cell lines. siRNA-mediated knockdown of HOXA10, HOXC9, HOXC10 or HOXC13 was performed in HNSC cell lines, and predicted transcriptional targets HOX genes was analyzed by bioinformatic.

RESULTS

Thirty-one out of the 39 mammalian HOX genes were found upregulated in HNSC tissues and cell lines. The HOXC9, HOXC10 or HOXC13 knockdown attenuated cell migration, and lead to downregulation of epithelial-mesenchymal transition (EMT) markers, which were predicted as transcriptional targets of these three HOX genes. Diminished colony formation and cell cycle arrest after HOXC10 or HOXC13 knockdown were also observed, corroborating the fact that there was an enrichment for genes in proliferation/cell cycle pathways.

CONCLUSIONS

In summary, we revealed roles for HOXC9, HOXC10, and HOXC13 in cell migration and proliferation/cell cycle progression in HNSC cells and suggested that those HOX members contribute to HNSC development possibly by regulating tumor growth and metastasis.

7-Epitaxol Induces Apoptosis and Autophagy in Head and Neck Squamous Cell Carcinoma through Inhibition of the ERK Pathway

As the main derivative of paclitaxel, 7-Epitaxol is known to a have higher stability and cytotoxicity. However, the anticancer effect of 7-Epitaxol is still unclear. The purpose of this study was to explore the anticancer effects of 7-Epitaxol in squamous cell carcinoma of the head and neck (HNSCC). Our study findings revealed that 7-Epitaxol potently suppressed cell viability in SCC-9 and SCC-47 cells by inducing cell cycle arrest. Flow cytometry and DAPI staining demonstrated that 7-Epitaxol treatment induced cell death, mitochondrial membrane potential and chromatin condensation in OSCC cell lines. The compound regulated the proteins of extrinsic and intrinsic pathways at the highest concentration, and also increased the activation of caspases 3, 8, 9, and PARP in OSCC cell lines. Interestingly, a 7-Epitaxol-mediated induction of LC3-I/II expression and suppression of p62 expression were observed in OSCC cells lines. Furthermore, the MAPK inhibitors indicated that 7-Epitaxol induces apoptosis and autophagy marker proteins (cleaved-PARP and LC3-I/II) by reducing the phosphorylation of ERK1/2. In conclusion, these findings indicate the involvement of 7-Epitaxol in inducing apoptosis and autophagy through ERK1/2 signaling pathway, which identify 7-Epitaxol as a potent cytotoxic agent in HNSCC.

The evaluation of the reliability and validity properties of the Greek version of the xerostomia questionnaire (ΧQ)

PURPOSE

Xerostomia is one of the multidimensional effects of cancer therapy that can impact on patients' quality of life. This study aims to evaluate the reliability and validity properties of the xerostomia questionnaire.

METHODS

The data were retrieved from a randomized, interventional and longitudinal follow-up study of 72 head and neck cancer patients on active oral radiotherapy. Data were retrieved by the Xerostomia Questionnaire, the EORTC-QLQ C30 and EORT QLQ HN35. Data analyzes included intrinsic credibility of affinity Cronbach alpha factor, which is related to validity and cross-sectional validity.

RESULTS

The Cronbach's alpha index of the Greek version of the questionnaire was high. Explicitly, the total scale of the questionnaire had an α = 0.97, and the individual dimensions - Degree of dryness and the quality of life had an alpha of 0.97 and 0.98 respectively. The xerostomia dimension of the questionnaire has a high positive correlation with QLQ C30 overall (r = 0.61, p < 0.001), and with the HN35 xerostomia dimension (r = 0.63, p < 0.001) which demonstrate its' concurrent validity. The dimensions of the xerostomia questionnaire were highly correlated with the EORTC-QLQ C30 dimensions which supports its' predictive validity. The level of xerostomia and the quality of life varied according to the level of pain of the patients (p < 0.001) that support the cross-sectional validity of the questionnaire.

CONCLUSION

The Greek version of the xerostomia questionnaire is a reliable and valid tool for use in head and neck cancer patients on active oral radiotherapy.

𝛽-Catenin-a Possible Prognostic Molecular Marker for Recurrence in Histopathologically Negative Surgical Margin of Oral Cancer

The locoregional recurrence in oral cancer is not predicted by the histopathological parameters solely as the normal morphological looking cells harbor the genomic instability which acts as the potential tumor cells for recurrence in future. Therefore, there is an urgent need of the biomarker for prognostic stratification of patients with high risk of disease recurrence and appropriate management. Eighty oral squamous cell carcinoma (OSCC) patients were included in the study during the period 2012 to 2014 at Apollo Hospitals and Kalinga Institute of Medical sciences, Bhubaneswar. OSCC tissue samples were collected at the time of surgical excision, and immunohistochemistry (IHC) was performed to check the expression of β-catenin in cut margin (CM) and tumor. Statistical analysis was carried out using SPSS based on clinical and pathological records. It was observed that among 80 patients, 33.75% (27 patients) developed recurrence. The recurrence rate was low for 6 out of 27 patients (22.2%) where β-catenin is positive in tumor and negative in cut margin, while it was quite high in 21 out of 27 (77.8%) when marker is negative in tumor but positive in cut margin (CM). The odds of recurrence among patients having high levels of 𝛽-catenin in CM was 3.6 times higher than the odds of recurrence among patients having lower levels of 𝛽-catenin in CM (p < 0.017). In conclusion, this study highlighted that 𝛽-catenin can be included as a prognostic molecular marker, along with routine histopathological study to influence therapeutic decisions and appropriate management of disease.

Characterization of perineural invasion in different histological grades and variants of oral squamous cell carcinoma

Background:

Oral squamous cell carcinoma (OSCC) accounts for 3% of all malignant neoplasms and is the fifth most frequent cancer in the world. They usually spread by hematogenous or lymphatic spread, and perineural invasion (PNI) is considered an alternate method of tumor spread where it is described as the tumor affinity toward a neural tissue.

Aim and Objectives:

The present study aims to evaluate the biological behavior of OSCC with respect to PNI and to evaluate the importance of PNI with respect to different histopathological grades and variants, tumor stage and lymph node status of OSCC. PNI was also assessed with respect to its frequency, patterns, types and number in various grades of OSCC.

Materials and Methods:

This retrospective, double-blind study was conducted on 148 histopathologically proven cases of different histopathological grades and variants of OSCC. The tissue sections were examined for PNI and its patterns and were further compared with habit history, site of the lesion, tumor staging, grading and lymph node status.

Results:

A Chi-square test was performed. A percentage positivity of 45.27% (67 cases) among 148 cases was found. PNI positivity of 63.6% and 50% was observed in T4 and T3 tumor stages, respectively, with high significance. Seventy percent of cases belonging to poorly differentiated squamous cell carcinoma showed positivity for PNI, which was statistically significant. PNI positivity with respect to lymph node status is nonsignificant.

Conclusion:

The present study showed that there is a direct proportionality between PNI and different grades and stages of OSCC. Given this context, a histopathologist ought to examine for PNI and make it mandatory to report the same to the clinician for better treatment and follow-up of the patient.

Profiling the Stromal and Vascular Heterogeneity in Patient-derived Xenograft Models of Head and Neck Cancer: Impact on Therapeutic Response

Head and neck squamous cell carcinomas (HNSCC) represent a group of epithelial neoplasms that exhibit considerable heterogeneity in clinical behavior. Here, we examined the stromal and vascular heterogeneity in a panel of patient-derived xenograft (PDX) models of HNSCC and the impact on therapeutic response. Tumor sections from established tumors were stained for p16 (surrogate for human papillomavirus (HPV) infection), stromal (Masson’s trichrome) and vascular (CD31) markers. All PDX models retained the HPV/p16 status of the original patient tumor. Immunohistochemical evaluation revealed the presence of multiple vessel phenotypes (tumor, stromal or mixed) in the PDX panel. Vascular phenotypes identified in the PDX models were validated in a tissue microarray of human HNSCC. Treatment with a microtubule targeted vascular disrupting agent (VDA) resulted in a heterogeneous antivascular and antitumor response in PDX models. The PDX with the tumor vessel phenotype that exhibited higher CD31+ vessel counts and leaky vasculature on magnetic resonance imaging (MRI) was sensitive to VDA treatment while the PDX with the stromal vessel phenotype was resistant to therapy. Collectively, our results demonstrate the phenotypic and functional vascular heterogeneity in HNSCC and highlight the impact of this heterogeneity on response to antivascular therapy in PDX models of HNSCC.

Adaptive Responses to Monotherapy in Head and Neck Cancer: Interventions for Rationale-Based Therapeutic Combinations

Most Phase II and III clinical trials in head and neck cancer (HNC) combine two or more treatment modalities, which are based, in part, on knowledge of the molecular mechanisms of innate and acquired resistance to monotherapy. In this review, we describe the range of tumor-cell autonomously derived (intrinsic) and tumor-microenvironment-derived (extrinsic) acquired-resistance mechanisms to various FDA-approved monotherapies for HNC. Specifically, we describe how tumor cells and the tumor microenvironment (TME) respond to radiation, chemotherapy, targeted therapy (cetuximab), and immunotherapies [programmed cell death 1 (PD-1) inhibitors] and adapt to the selective pressure of these monotherapies. Due to the diversity of adaptive responses to monotherapy, monitoring the response to treatment in patients is critical to understand the path that leads to resistance and to guide the optimal therapeutic drug combinations in the clinical setting. We envisage that applying such a rationale-based therapeutic strategy will improve treatment efficacy in HNC patients.

A positive feedback loop involving EGFR/Akt/mTORC1 and IKK/NF-kB regulates head and neck squamous cell carcinoma proliferation

The overexpression or mutation of epidermal growth factor receptor (EGFR) has been associated with a number of cancers, including head and neck squamous cell carcinoma (HNSCC). Increasing evidence indicates that both the phosphatidylinositol-3-kinase (PI3K)-Akt-mammalian target of Rapamycin (mTOR) and the nuclear factor-kappa B (NF-κB) are constitutively active and contribute to aggressive HNSCC downstream of EGFR. However, whether these two oncogenic signaling pathways exhibit molecular and functional crosstalk in HNSCC is unclear. Our results now reveal that mTORC1, not mTORC2, contributes to NF-κB activation downstream of EGFR/PI3K/Akt signaling. Mechanistically, mTORC1 enhances the inhibitor of nuclear factor kappa-B kinase (IKK) activity to accelerate NF-κB signaling. Concomitantly, activated NF-κB/IKK up-regulates EGFR expression through positive feedback regulation. Blockage of NF-κB/IKK activity by the novel IKKβ specific inhibitor, CmpdA, leads to significant inhibition of cell proliferation and induction of apoptosis. CmpdA also sensitizes intrinsic cisplatin-resistant HNSCC cells to cisplatin treatment. Our findings reveal a new mechanism by which EGFR/PI3K/Akt/mTOR signaling promotes head and neck cancer progression and underscores the need for developing a therapeutic strategy for targeting IKK/NF-κB either as a single agent or in combination with cisplatin in head and neck cancer.

Detection of clinically relevant copy number alterations in oral cancer progression using multiplexed droplet digital PCR

Copy number alterations (CNAs), a common genomic event during carcinogenesis, are known to affect a large fraction of the genome. Common recurrent gains or losses of specific chromosomal regions occur at frequencies that they may be considered distinctive features of tumoral cells. Here we introduce a novel multiplexed droplet digital PCR (ddPCR) assay capable of detecting recurrent CNAs that drive tumorigenesis of oral squamous cell carcinoma. Applied to DNA extracted from oral cell lines and clinical samples of various disease stages, we found good agreement between CNAs detected by our ddPCR assay with those previously reported using comparative genomic hybridization or single nucleotide polymorphism arrays. Furthermore, we demonstrate that the ability to target specific locations of the genome permits detection of clinically relevant oncogenic events such as small, submicroscopic homozygous deletions. Additional capabilities of the multiplexed ddPCR assay include the ability to infer ploidy level, quantify the change in copy number of target loci with high-level gains, and simultaneously assess the status and viral load for high-risk human papillomavirus types 16 and 18. This novel multiplexed ddPCR assay therefore may have clinical value in differentiating between benign oral lesions from those that are at risk of progressing to oral cancer.

PRMT1 expression is elevated in head and neck cancer and inhibition of protein arginine methylation by adenosine dialdehyde or PRMT1 knockdown downregulates proliferation and migration of oral cancer cells

Protein arginine methylation is a post-translational modification that has been implicated in signal transduction, gene transcription, DNA repair and RNA processing. Overexpression or deregulation of protein arginine methyltransferases (PRMTs) have been reported to be associated with various cancers but have not been studied in head and neck cancer (HNC). We investigated the involvement of the modification in HNC using oral cancer cell lines (SAS, OECM-1 and HSC-3) and an immortalized normal oral cells (S-G). The expression levels of the predominant PRMT1 were generally consistent with the levels of asymmetric dimethylarginine (ADMA), highest in SAS and OECM1, then S-G and low in HSC-3. Upon the treatment with an indirect methyltransferase inhibitor adenosine dialdehyde (AdOx), the ADMA levels in SAS and OECM1, but not that in S-G and HSC-3, decreased significantly. SAS and OECM with high ADMA levels grew faster than HSC-3 and S-G. The growth rate of the fast growing SAS and OECM, but not that of the other two cell lines, decreased significantly upon AdOx treatment. The migration activity of SAS and HSC-3, two cell lines with migration ability also decreased after the AdOx treatment. Immunohistochemical analyses of specimens from typical HNC patients showed strong PRMT1 expression in the tumor cells compared with neighboring normal cells. Knockdown of PRMT1 in SAS cells decreased the levels of PRMT1 and ADMA-containing proteins significantly. These cells showed decreased growth rate, reduced migration activity but increased expression of the epithelial marker E-cadherin. The present study thus provides fundamental background for evaluation of the PRMT1 gene as the therapeutic targets of HNC.

Omics-based molecular techniques in oral pathology centred cancer: prospect and challenges in Africa

BACKGROUND

The completion of the human genome project and the accomplished milestones in the human proteome project; as well as the progress made so far in computational bioinformatics and "big data" processing have contributed immensely to individualized/personalized medicine in the developed world.

MAIN BODY

At the dawn of precision medicine, various omics-based therapies and bioengineering can now be applied accurately for the diagnosis, prognosis, treatment, and risk stratification of cancer in a manner that was hitherto not thought possible. The widespread introduction of genomics and other omics-based approaches into the postgraduate training curriculum of diverse medical and dental specialties, including pathology has improved the proficiency of practitioners in the use of novel molecular signatures in patient management. In addition, intricate details about disease disparity among different human populations are beginning to emerge. This would facilitate the use of tailor-made novel theranostic methods based on emerging molecular evidences.

CONCLUSION

In this review, we examined the challenges and prospects of using currently available omics-based technologies vis-à-vis oral pathology as well as prompt cancer diagnosis and treatment in a resource limited setting.

Copy number profiling of tumor suppressor genes in head and neck cancer

BACKGROUND

Sensitive and reliable new biomarkers are needed in head and neck cancer to predict the outcome and for therapy that is more effective. Copy number alterations are frequent and play a critical role in cancer.

METHODS

Copy number alterations of 24 tumor suppressor genes in head and neck cancer were analyzed simultaneously in matched tumor and normal samples from 93 patients using multiplex ligation-dependent probe amplification (MLPA).

RESULTS

Chromosomes 3p and 9p displayed the most common alterations. The gene displaying most frequent losses was the mutL homolog 1 (MLH1) gene, followed by the cyclin-dependent kinase inhibitor 2A (CDKN2A) and CDKN2B genes. A significant correlation was observed between the CDKN2A and CDKN2B genes. The tissue inhibitor of metalloproteinase (TIMP)3 gene alterations were observed in 8 tumors.

CONCLUSION

Our data confirm previous observations and suggest that losses of the MLH1 and CDKN2 genes and alterations of the TIMP3 gene play an important role in head and neck carcinogenesis. © 2016 Wiley Periodicals, Inc. Head Neck 39: 341-346, 2017.

Prognostic significance of the tumour-adjacent tissue in head and neck cancers

Even with significant advances in operative skills and adjuvant therapies, the overall survival of patients suffering with head and neck squamous cancers (HNSCC) is unsatisfactory. Accordingly, no clinically useful prognostic biomarkers have been found yet for HNSCC. Many studies analysed the expression of potential markers in tumour tissues compared to adjacent tissues. Nevertheless, due to the sharing of the same microenvironment, adjacent tissues show molecular similarity to tumour tissues. Thus, gene expression patterns of 94 HNSCC tumorous tissues were compared with 31 adjacent tissues and with 10 tonsillectomy specimens of non-cancer individuals. The genes analysed at RNA level using quantitative RT-PCR and correlated with clinico-pathological conditions were as follows: EGF, EGFR, MKI67, BCL2, BAX, FOS, JUN, TP53, VEGF, FLT1, MMP2, MMP9, MT1A and MT2A. The elevated MT2A, BAX, EGF and JUN expression was associated with the influence of tumour cells on the rearrangement of healthy tissues, as well as a significant shift in the BAX/BCL2 ratio. Our investigation also indicated that adjacent tissues play an important role in cancerogenesis by releasing several tumour-supporting factors such as EGF. A gradual increase in the metallothionein expression, from the lowest one in tonsillectomy samples to the highest ones in tumour samples, suggests that MT expression might be tissue reaction to the presence of tumour cells. The results of this study confirmed the significance of metallothionein in tumori-genesis and gave evidences for its use as a potential HNSCC biomarker. Furthermore, this study highlighted the importance of histologically normal tumour-adjacent tissue in prediction of HNSCC progress.

Radioresistance in head and neck squamous cell carcinoma: Biological bases and therapeutic implications

Head and neck squamous cell carcinoma (HNSCC) is strongly associated with alcohol and tobacco consumption. Lately, the incidence of human papillomavirus (HPV)-related tumors has shown a significant increase, and HPV-related tumors show distinctive features if compared with the HPV-negative counterpart. Locally advanced HNSCC can be treated with concomitant chemoradiotherapy, but early recurrences sometimes occur. Relapses are often related to an intrinsic radioresistance of the tumors. Alterations in intracellular pathways, primarily involved in cell proliferation, apoptosis, and DNA repair, can lead to radioresistance. Preclinical and clinical evidence highlighted that 3 main pathways, including the epidermal growth factor receptor (EGFR), the phosphotidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR), and the p53 signaling cascades, play a crucial role in radioresistance development. A future approach may consist in the association of radiotherapy (RT) and selective inhibition of the key pathways involved in radioresistance. Phase I, II, and III clinical trials are currently testing these novel treatment strategies.

Intrinsic and extrinsic control of expression of the immunoregulatory molecule PD-L1 in epithelial cells and squamous cell carcinoma

Recent clinical results for PD-1 blockade therapy have demonstrated durable tumor control with minimal immune-related adverse effects. PD-L1 is induced in non-lymphoid tissue cells and tumor cells, in addition to tissue-recruiting immune cells, under inflammatory conditions triggered by several cytokines, especially IFN-γ, and exogenous stimuli delivered by pathogen-associated molecular patterns. Receptor-mediated signaling molecules that affect the cell cycle, proliferation, apoptosis, and survival (including NF-κB, MAPK, PI3K, mTOR, and JAK/STAT) are involved in PD-L1 induction. PD-L1 expression in tumor cells is also triggered by the signals described above, but in some instances, intrinsic cell alteration associated with carcinogenesis contributes to PD-L1 induction. The tumor suppressor genes PTEN and Lkb1 and epithelial-mesenchymal transition-related molecules are also involved in the regulation of PD-L1 expression. Notably, squamous cell carcinoma of the head and neck (SCCHN) often exhibits both host immunosuppression and cytogenetic alternations of tumor cells. Precise understanding of how PD-L1 expression is controlled will allow the development of effective approaches to PD-1 blockade therapy for patients with SCCHN.

Quantitative proteomic analysis of sphere-forming stem-like oral cancer cells

Introduction

The purpose of this study is to identify target proteins that may play important functional roles in oral cancer stem-like cells (CSCs) using mass spectrometry-based quantitative proteomics.

Methods

Sphere-formation assays were performed on highly invasive UM1 and lowly invasive UM2 oral cancer cell lines, which were derived from the same tongue squamous cell carcinoma, to enrich CSCs. Quantitative proteomic analysis of CSC-like and non-CSC UM1 cells was carried out using tandem mass tagging and two-dimensional liquid chromatography with Orbitrap mass spectrometry.

Results

CSC-like cancer cells were found to be present in the highly invasive UM1 cell line but absent in the lowly invasive UM2 cell line. Stem cell markers SOX2, OCT4, SOX9 and CD44 were up-regulated, whereas HIF-1 alpha and PGK-1 were down-regulated in CSC-like UM1 cells versus non-CSC UM1 cells. Quantitative proteomic analysis indicated that many proteins in cell cycle, metabolism, G protein signal transduction, translational elongation, development, and RNA splicing pathways were differentially expressed between the two cell phenotypes. Both CREB-1-binding protein (CBP) and phosphorylated CREB-1 were found to be significantly over-expressed in CSC-like UM1 cells.

Conclusions

CSC-like cells can be enriched from the highly invasive UM1 oral cancer cell line but not from the lowly invasive UM2 oral cancer cell line. There are significant proteomic alterations between CSC-like and non-CSC UM1 cells. In particular, CBP and phosphorylated CREB-1 were significantly up-regulated in CSC-like UM1 cells versus non-CSC UM1 cells, suggesting that the CREB pathway is activated in the CSC-like cells.

Translational genomics and head and neck cancer: toward precision medicine

Head and neck squamous cell carcinoma (HNSCC) comprise a wide spectrum of neoplasms with different tumor biologies, prognosis and response to therapies. Current tumor classification and traditional diagnostic methods (e.g. clinical assessment, histopathology) are limited in their capacity to determine prognosis and clinical decision-making. Despite recent improvements in treatment, the outcome for patients with HNSCC remains poor. Similar to most tumors, several patient-related factors, (e.g. genetics and environment) and disease-related factors (e.g. tumor location, TMN staging) play a significant role on survival. Thus, the problem in defining the prognosis is that the clinical course and response to treatment differ considerably among patients. Such interindividual variability is related to the heterogeneity of the tumor, genetic and epigenetic variations, thus reflecting the interaction of multiple biological components that result in a unique phenotype. Integrative genomics are developed to identify the molecular pathways leading to cancer at the individual level and find novel prognostic markers for HNSCC, hence tailoring a treatment accordingly. Such genetic-based personalized diagnosis allows tumor stratification and implementation of targeted therapy. Modern medicine includes new drugs that disrupt the implicated molecules and their signaling pathways. Here, we summarize the current state of knowledge that elucidates the translation of genetic data into clinical benefit.

MDA-9/Syntenin regulates differentiation and angiogenesis programs in head and neck squamous cell carcinoma

Little is known about the molecular pathways regulating poor differentiation and invasion of head and neck squamous cell carcinoma (HNSCC). In the present study, we aimed to determine the role of MDA-9/Syntenin, a metastasis associated molecule in HNSCC tumorigenesis. Elevated MDA-9/Syntenin expression was evident in 67% (54/81) primary HNSCC tumors (p=0.001-0.002) and 69% (9/13) pre-neoplastic tissues (p=0.02-0.03). MDA-9/Syntenin overexpression was associated with the stage (p=0.001), grade (p=0.001) and lymph node metastasis (p=0.0001). Silencing of MDA-9/Syntenin in 3 poorly differentiated HNSCC cell lines induced squamous epithelial cell differentiation, disrupted angiogenesis and reduced tumor growth in vitro and in vivo. We confirmed SPRR1B and VEGFR1 as the key molecular targets of MDA-9/Syntenin on influencing HNSCC differentiation and angiogenesis respectively. MDA-9/Syntenin disrupted SPRR1B expression interacting through its PDZ1 domain and altered VEGFR1 expression in vitro and in vivo. VEGFR1 co-localized with MDA-9/Syntenin in HNSCC cell lines and primary tumor. Downregulation of growth regulatory molecules CyclinD1, CDK4, STAT3, PI3K and CTNNB1 was also evident in the MDA-9/Syntenin depleted cells, which was reversed following over-expression of MDA-9/Syntenin in immortalized oral epithelial cells. Our results suggest that early induction of MDA-9/Syntenin expression influences HNSCC progression and should be further evaluated for potential biomarker development.

HPV-related oropharyngeal cancers: from pathogenesis to new therapeutic approaches

Head and neck cancers are a heterogeneous group of malignancies accounting for approximately 600,000 new cases every year worldwide. Human papillomavirus (HPV)-related oropharyngeal cancers represent a new nosological entity for pathogenesis, molecular mechanisms, prognostic trend and therapeutic response. Several clinical trials have shown that HPV-positive/p16-positive cancer patients have a favorable prognosis demanding for de-escalation of current therapies. Comprehensive genomic analyses allowed to identify specific genetic alterations in targetable genes envisaging novel approaches to treat different subset of HPV-related and HPV-unrelated oropharyngeal cancers. Furthermore virus associated head and neck cancers may benefit from new developed immunotherapies targeting HPV E6 and E7 oncoproteins. We reviewed recent studies on the role of HPV infection in these cancers and present our current understanding of carcinogenic mechanisms providing possible novel approaches to cancer treatment.

Quantitative proteomic analysis of serum proteins from oral cancer patients: comparison of two analytical methods

Serum proteomic analysis can be a valuable approach for the discovery of protein biomarkers for early detection or monitoring of a disease. In this study, two analytical methods were compared for quantification of serum proteins in patients with oral cancer. In the first approach, we quantified serum proteins between oral squamous cell carcinoma (OSCC) and healthy control subjects by performing in-solution digestion of serum proteins, isobaric tags for relative and absolute quantification (iTRAQ) labeling of the resulting peptides, strong cation exchange (SCX) fractionation of labeled peptides and finally capillary liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis of the peptides. In the second approach, we first separated serum proteins with SDS-PAGE. The gel-separated proteins were then digested with trypsin and the resulting peptides were labeled with iTRAQ and analyzed with LC-MS/MS for protein quantification. A total of 319 serum proteins were quantified with the first proteomic approach whereas a total of 281 proteins were quantified by the second proteomic approach. Most of the proteins were identified and quantified by both approaches, suggesting that these methods are similarly effective for serum proteome analysis. This study provides compelling evidence that quantitative serum proteomic analysis of OSCC is a valuable approach for identifying differentially expressed proteins in cancer patients’ circulation systems that may be used as potential biomarkers for disease detection. Further validation in large oral cancer patient populations may lead to a simple and low invasive clinical tool for OSCC diagnosis or monitoring.

Epigenetic changes in carcinogenesis of gallbladder

Gallbladder cancer (GBC) is a lethal and a common malignancy affecting mostly females. There are restricted high incidence pockets across the world and in northern India highest incidence of GBC is reported from the Gangetic belt. The etiology of this disease remains largely unknown though several risk factors have been stated. The genetic aberrations in GBC involving mutations in tumor suppressor genes and oncogenes have been reported in literature. However, there is scarcity of data regarding epigenetic changes that may also be involved in gallbladder carcinogenesis. This review attempts to summarize our current understanding of the epigenetic changes in GBC.

Tumor-infiltrating immune cells promoting tumor invasion and metastasis: existing theories

It is a commonly held belief that infiltration of immune cells into tumor tissues and direct physical contact between tumor cells and infiltrated immune cells is associated with physical destructions of the tumor cells, reduction of the tumor burden, and improved clinical prognosis. An increasing number of studies, however, have suggested that aberrant infiltration of immune cells into tumor or normal tissues may promote tumor progression, invasion, and metastasis. Neither the primary reason for these contradictory observations, nor the mechanism for the reported diverse impact of tumor-infiltrating immune cells has been elucidated, making it difficult to judge the clinical implications of infiltration of immune cells within tumor tissues. This mini-review presents several existing hypotheses and models that favor the promoting impact of tumor-infiltrating immune cells on tumor invasion and metastasis, and also analyzes their strength and weakness.

Molecular and cellular processes underlying the hallmarks of head and neck cancer

The hallmarks of cancer were updated by Hanahan and Weinberg in 2011. Here we discuss the updated hallmarks in relation to what is known of the molecular and cellular processes underlying the development of head and neck squamous cell carcinoma (HNSCC). Several mechanisms are described, and recent surveys of HNSCC suggest a limited number of mutations, from which more mechanisms may emerge. There are also epigenetic changes to the control of normal processes. More than one mechanism underlies each hallmark. Processes essential to the development of HNSCC need not be essential to the proliferation of the fully developed tumour. Attention is paid to the emerging hallmarks, deregulation of cellular energy metabolism and evasion of immune destruction, and enabling characteristics, genome instability and mutation and tumour-promoting inflammation. HNSCC may adapt to hypoxia, suppress HLA expression, and express Toll-like receptors to facilitate inflammation, which support the proliferation of the tumour.