Receptor-tyrosine-kinase-targeted therapies for head and neck cancer

Super enhancer loci of EGFR regulate EGFR variant 8 through enhancer RNA and strongly associate with survival in HNSCCs

Epidermal growth factor receptor (EGFR) has been shown to be overexpressed in human cancers due to mutation, amplification, and epigenetic hyperactivity, which leads to deregulated transcriptional mechanism. Among the eight different EGFR isoforms, the mechanism of regulation of full-length variant 1 is well-known, no studies have examined the function & factors regulating the expression of variant 8. This study aimed to understand the function of EGFR super-enhancer loci and its associated transcription factors regulating the expression of EGFR variant 8. Our study shows that overexpression of variant 8 and its transcription was more prevalent than variant 1 in many cancers and positively correlated with the EGFR-AS1 expression in oral cancer and HNSCC. Notably, individuals overexpressing variant 8 showed shorter overall survival and had a greater connection with other clinical traits than patients with overexpression of variant 1. In this study, TCGA enhancer RNA profiling on the constituent enhancer (CE1 and CE2) region revealed that the multiple enhancer RNAs formed from CE2 by employing CE1 as a promoter. Our bioinformatic analysis further supports the enrichment of enhancer RNA specific chromatin marks H3K27ac, H3K4me1, POL2 and H2AZ on CE2. GeneHancer and 3D chromatin capture analysis showed clustered interactions between CE1, CE2 loci and this interaction may regulates expression of both EGFR-eRNA and variant 8. Moreover, increased expression of SNAI2 and its close relationship to EGFR-AS1 and variant 8 suggest that SNAI2 could regulates variant 8 overexpression by building a MegaTrans complex with both EGFR-eRNA and EGFR-AS1. Our findings show that EGFR variant 8 and its transcriptional regulation & chromatin modification by eRNAs may provide a rationale for targeting RNA splicing in combination with targeted EGFR therapies in cancer.

New insights into RAS in head and neck cancer

RAS genes are known to be dysregulated in cancer for several decades, and substantial effort has been dedicated to develop agents that reduce RAS expression or block RAS activation. The recent introduction of RAS inhibitors for cancer patients highlights the importance of comprehending RAS alterations in head and neck cancer (HNC). In this regard, we examine the published findings on RAS alterations and pathway activations in HNC, and summarize their role in HNC initiation, progression, and metastasis. Specifically, we focus on the intrinsic role of mutated-RAS on tumor cell signaling and its extrinsic role in determining tumor-microenvironment (TME) heterogeneity, including promoting angiogenesis and enhancing immune escape. Lastly, we summarize the intrinsic and extrinsic role of RAS alterations on therapy resistance to outline the potential of targeting RAS using a single agent or in combination with other therapeutic agents for HNC patients with RAS-activated tumors.

Design, Synthesis, Anticancer Activity and Molecular Docking of New 1,2,3-Triazole-Based Glycosides Bearing 1,3,4-Thiadiazolyl, Indolyl and Arylacetamide Scaffolds

New 1,3,4-thiadiazole thioglycosides linked to a substituted arylidine system were synthesized via heterocyclization via click 1,3-dipolar cycloaddition. The click strategy was used for the synthesis of new 1,3,4-thiadiazole and 1,2,3-triazole hybrid glycoside-based indolyl systems as novel hybrid molecules by reacting azide derivatives with the corresponding acetylated glycosyl terminal acetylenes. The cytotoxic activities of the compounds were studied against HCT-116 (human colorectal carcinoma) and MCF-7 (human breast adenocarcinoma) cell lines using the MTT assay. The results showed that the key thiadiazolethione compounds, the triazole glycosides linked to p-methoxyarylidine derivatives and the free hydroxyl glycoside had potent activity comparable to the reference drug, doxorubicin, against MCF-7 human cancer cells. Docking simulation studies were performed to check the binding patterns of the synthesized compounds. Enzyme inhibition assay studies were also conducted for the epidermal growth factor receptor (EGFR), and the results explained the activity of a number of derivatives.

EGFR Mutations in Head and Neck Squamous Cell Carcinoma

EGFR is a prototypical receptor tyrosine kinase that is overexpressed in multiple cancers including head and neck squamous cell carcinoma (HNSCC). The standard of care for HNSCC remains largely unchanged despite decades of research. While EGFR blockade is an attractive target in HNSCC patients and anti-EGFR strategies including monoclonal antibodies and kinase inhibitors have shown some clinical benefit, efficacy is often due to the eventual development of resistance. In this review, we discuss how the acquisition of mutations in various domains of the EGFR gene not only alter drug binding dynamics giving rise to resistance, but also how mutations can impact radiation response and overall survival in HNSCC patients. A better understanding of the EGFR mutational landscape and its dynamic effects on treatment resistance hold the potential to better stratify patients for targeted therapies in order to maximize therapeutic benefits.

Design, synthesis and anticancer evaluation of new 4-anilinoquinoline-3-carbonitrile derivatives as dual EGFR/HER2 inhibitors and apoptosis inducers

Dual targeting of EGFR/HER2 receptor is an attractive strategy for cancer therapy. Four series of 4-anilinoquinoline-3-carbonitrile derivatives were designed and prepared by introducing various functional groups, including a polar hydrophilic group (carboxylic acid), a heterocyclic substituent possessing polarity to some extent, and an unpolar hydrophobic phenyl portion, at the C-6 position of the quinoline skeleton. All of the prepared derivatives were screened for their inhibitory activities against EGFR /HER2 receptors and their antiproliferative activities against the SK-BR-3 and A431 cell lines. Compounds 6a, 6 g and 6d exhibited significant activities against the target cell lines. In particular, the antiproliferative activity of 6d (IC₅₀ = 1.930 μM) against SK-BR-3 was over 2-fold higher than that of neratinib (IC₅₀ = 3.966 μM), and comparable to that of Lapatinib (IC₅₀ = 2.737 μM). On the other hand, 6d (IC₅₀ = 1.893 μM) was more active than the reference drug Neratinib (IC₅₀ = 2.151 μM), and showed comparable potency to Lapatinib (IC₅₀ = 1.285 μM) against A431. Cell cycle analysis and apoptosis assays indicated that 6d arrests the cell cycle in the S phase, and it is a potent apoptotic inducer. Moreover, molecular docking exhibited the binding modes of compound 6d in EGFR and HER2 binding sites, respectively. Compound 6d can be considered as a candidate for further investigation as a more potent anticancer agent.

Therapeutic Potential of Antibody-Drug Conjugate-Based Therapy in Head and Neck Cancer: A Systematic Review

BACKGROUND

Antibody-drug conjugates (ADCs) are designed to deliver potent cytotoxic agents into tumor tissues. During the last two decades, a plethora of ADCs have been successfully developed and used for several indications, including hematologic and solid tumors. In this work, we systematically reviewed the progress in ADC development for the treatment of HNC.

METHODS

This review was registered in PROSPERO database. A comprehensive search was conducted following PRISMA guidelines and using PubMed, Scopus and Web of Science database.

RESULTS

In total, 19 studies were included. Due to the significant heterogeneity of the outcome measures, meta-analysis was not performed, and data were summarized in tables. HNC results are poorly represented in the cohorts of completed clinical trials; published data are mostly focused on safety evaluation rather than efficacy of ADCs.

CONCLUSIONS

Although several novel agents against a wide range of different antigens were investigated, showing promising results at a preclinical level, most of the targets reported in this review are not specific for HNC; hence, the development of ADCs tailored for the HNC phenotype could open up new therapeutic perspectives. Moreover, the results from the present systematic review call attention to how limited is the application of current clinical trials in HNC.

Genetic variant rs10251977 (G>A) in EGFR-AS1 modulates the expression of EGFR isoforms A and D

Tyrosine kinase inhibitor is an effective chemo-therapeutic drug against tumors with deregulated EGFR pathway. Recently, a genetic variant rs10251977 (G>A) in exon 20 of EGFR reported to act as a prognostic marker for HNSCC. Genotyping of this polymorphism in oral cancer patients showed a similar frequency in cases and controls. EGFR-AS1 expressed significantly high level in tumors and EGFR-A isoform expression showed significant positive correlation (r = 0.6464, p < 0.0001) with reference to EGFR-AS1 expression levels, consistent with larger TCGA HNSCC tumor dataset. Our bioinformatic analysis showed enrichment of alternative splicing marks H3K36me3 and presence of intronic polyA sites spanning around exon 15a and 15b of EGFR facilitates skipping of exon 15b, thereby promoting the splicing of EGFR-A isoform. In addition, high level expression of PTBP1 and its binding site in EGFR and EGFR-AS1 enhances the expression of EGFR-A isoform (r = 0.7404, p < 0.0001) suggesting that EGFR-AS1 expression modulates the EGFR-A and D isoforms through alternative splicing. In addition, this polymorphism creates a binding site for miR-891b in EGFR-AS1 and may negatively regulate the EGFR-A. Collectively, our results suggested the presence of genetic variant in EGFR-AS1 modulates the expression of EGFR-D and A isoforms.

Precision Medicine Approaches to Overcome Resistance to Therapy in Head and Neck Cancers

Head and neck squamous cell carcinoma (HNSCC) is the sixth most incident cancer worldwide. More than half of HNSCC patients experience locoregional or distant relapse to treatment despite aggressive multimodal therapeutic approaches that include surgical resection, radiation therapy, and adjuvant chemotherapy. Before the arrival of immunotherapy, systemic chemotherapy was previously employed as the standard first-line protocol with an association of cisplatin or carboplatin plus 5-fluorouracil plus cetuximab (anti-EFGR antibody). Unfortunately, acquisition of therapy resistance is common in patients with HNSCC and often results in local and distant failure. Despite our better understanding of HNSCC biology, no other molecular-targeted agent has been approved for HNSCC. In this review, we outline the mechanisms of resistance to the therapeutic strategies currently used in HNSCC, discuss combination treatment strategies to overcome them, and summarize the therapeutic regimens that are presently being evaluated in early- and late-phase clinical trials.

Effect of Lycopene on Oral Squamous Cell Carcinoma Cell Growth by Inhibiting IGF1 Pathway

Purpose

Lycopene has produced robust clinical effects and shows a promising chemopreventive in the oral cancer and precancerous lesions. However, much is still unknown about its mechanisms of the carotenoid in protecting against oral squamous cell carcinoma (OSCC). Insulin-like growth factor 1 (IGF1) pathway serves as a key regulatory signal pathway in the tumor microenvironment, which may be associated with the angiogenesis, tumorigenicity, and cancer proliferation. The current study was focused on elucidating the potential pathway played for lycopene to exert its function in treating with OSCC.

Materials and Methods

Firstly, we explored the dose- and time-response of CAL-27 and WSU-HN6 cells to lycopene. Both cells were incubated with various concentrations of lycopene (0.25, 0.5, 1, 2 µM). The inhibiting rate of cell proliferation was assessed using MTT assay. To observe the regulating effect of lycopene on OSCC, cell migration, apoptosis and tumor formation were detected in vitro and in vivo. The potential signaling pathways of OSCC cells treated with lycopene were analyzed by Affymetrix microarrays. And then, we investigated the changing of IGF1 signaling pathway, on the protein levels of tumor tissue after lycopene.

Results

Cell proliferation was inhibited by lycopene in a dose- and time-dependent manner. The optimum inhibition efficiencies for OSCC cells were also found. Further, the results also demonstrated that pre-treatment of OSCC with lycopene drastically induced cell apoptosis suppresses cell migration and tumor growth. Mechanistically, ingenuity pathway analysis further revealed that IGF1 pathway participate in killing effects on OSCC after treatment of lycopene. Lycopene may inhibit the pathway by regulating protein expression of IGF1, IGF binding protein (BP) 1, IGFBP3, transcription factor Jun/AP-1 (JUN), and forkhead box O1 (FOXO1).

Conclusion

These observations indicate that lycopene regulates OSCC cell growth by inhibiting IGF1 pathway, which may be a promising agent for the treatment of OSCC.

Wnt/β-Catenin Signaling in Oral Carcinogenesis

Oral carcinogenesis is a complex and multifactorial process that involves cumulative genetic and molecular alterations, leading to uncontrolled cell proliferation, impaired DNA repair and defective cell death. At the early stages, the onset of potentially malignant lesions in the oral mucosa, or oral dysplasia, is associated with higher rates of malignant progression towards carcinoma in situ and invasive carcinoma. Efforts have been made to get insights about signaling pathways that are deregulated in oral dysplasia, as these could be translated into novel markers and might represent promising therapeutic targets. In this context, recent evidence underscored the relevance of the Wnt/β-catenin signaling pathway in oral dysplasia, as this pathway is progressively "switched on" through the different grades of dysplasia (mild, moderate and severe dysplasia), with the consequent nuclear translocation of β-catenin and expression of target genes associated with the maintenance of representative traits of oral dysplasia, namely cell proliferation and viability. Intriguingly, recent studies provide an unanticipated connection between active β-catenin signaling and deregulated endosome trafficking in oral dysplasia, highlighting the relevance of endocytic components in oral carcinogenesis. This review summarizes evidence about the role of the Wnt/β-catenin signaling pathway and the underlying mechanisms that account for its aberrant activation in oral carcinogenesis.

RTKs in pathobiology of head and neck cancers

Non-communicable diseases contribute to 71% of the deaths worldwide, of which cancers rank second after cardiovascular diseases. Among all the cancers, head and neck cancers (HNC) are consequential in augmenting the global cancer incidence as well as mortality. Receptor tyrosine kinases (RTKs) are emphatic for the matter that they serve as biomarkers aiding the analysis of tumor progression and metastasis as well as diagnosis, prognosis and therapeutic progression in the patients. The extensive researches on HNC have made significant furtherance in numerous targeted therapies, but for the escalating therapeutic resistance. This review explicates RTKs in HNC, their signaling pathways involved in tumorigenesis, metastasis and stemness induction, the association of non-coding RNAs with RTKs, an overview of RTK based therapy and associated resistance in HNC, as well as a sneak peek into the HPV positive HNC and its therapy. The review extrapolates the cardinal role of RTKs and RTK based therapy as superior to other existing therapeutic interventions for HNC.

Plasma-based biomaterials for the treatment of cutaneous radiation injury

Cutaneous wounds caused by an exposure to high doses of ionizing radiation remain a therapeutic challenge. While new experimental strategies for treatment are being developed, there are currently no off‐the‐shelf therapies for the treatment of cutaneous radiation injury that have been proven to promote repair of the damaged tissues. Plasma‐based biomaterials are biologically active biomaterials made from platelet enriched plasma, which can be made into both solid and semi‐solid forms, are inexpensive, and are available as off‐the‐shelf, nonrefrigerated products. In this study, the use of plasma‐based biomaterials for the mitigation of acute and late toxicity for cutaneous radiation injury was investigated using a mouse model. A 2‐cm diameter circle of the dorsal skin was irradiated with a single dose of 35 Gy followed by topical treatment with plasma‐based biomaterial or vehicle once daily for 5 weeks postirradiation. Weekly imaging demonstrated more complete wound resolution in the plasma‐based biomaterial vs. vehicle group which became statistically significant (p < 0.05) at weeks 12, 13, and 14 postmaximum wound area. Despite more complete wound healing, at 9 and 17 weeks postirradiation, there was no statistically significant difference in collagen deposition or skin thickness between the plasma‐based biomaterial and vehicle groups based on Masson trichrome staining nor was there a statistically significant difference in inflammatory or fibrosis‐related gene expression between the groups. Although significant improvement was not observed for late toxicity, plasma‐based biomaterials were effective at promoting wound closure, thus helping to mitigate acute toxicity.

MERTK as a novel therapeutic target in head and neck cancer

Although head and neck cancer (HNSCC) is the sixth most common tumor entity worldwide therapy options remain limited leading to 5-year survival rates of only 50 %. MERTK is a promising therapeutic target in several tumor entities, however, its role in HNSCC has not been described yet. The aim of our study was to investigate the biological significance of MERTK and to evaluate its potential as a novel therapeutic target in this dismal tumor entity. In two large HNSCC cohorts (n=537 and n=520) we found that MERTK is overexpressed in one third of patients. In-vitro, MERTK overexpression led to increased proliferation, migration and invasion whereas MERTK inhibition with the small molecule inhibitor UNC1062 or MERTK knockdown reduced cell motility via the small GTPase RhoA.

Taken together, we are the first to show that MERTK is frequently overexpressed in HNSCC and plays an important role in tumor cell motility. It might therefore be a potential target for selected patients suffering from this dismal tumor entity.

Snail-Modulated MicroRNA 493 Forms a Negative Feedback Loop with the Insulin-Like Growth Factor 1 Receptor Pathway and Blocks Tumorigenesis

In this study, we have identified one microRNA, microRNA 493 (miR-493), which could simultaneously and directly regulate multiple genes downstream of the insulin-like growth factor 1 receptor (IGF1R) pathway, including IGF1R, by binding with complementary sequences in the 3' untranslated region (UTR) of mRNAs of IGF1R, insulin receptor substrate 1 (IRS1), and mitogen-activated protein kinase 1 (MAPK1), thereby potentiating their inhibitory function at multiple levels in development and progression of cancers. This binding was further confirmed by pulldown of miR with AGO-2 antibody. Further, results from head and neck samples showed that miR-493 levels were significantly downregulated in tumors, with a concomitant increase in the expression of IGF1R and key downstream effectors. Functional studies from miR-493 overexpression cells and nude-mouse models revealed the tumor suppressor functions of miR-493. Regulation studies revealed that Snail binds to the miR-493 promoter and represses it. We found the existence of a dynamic negative feedback loop in the regulation of IGF1R and miR-493 mediated via Snail. Our study showed that nicotine treatment significantly decreases the levels of miR-493-with a concomitant increase in the levels of Snail-an indication of progression of cells toward tumorigenesis, reestablishing the role of tobacco as a major risk factor for head and neck cancers and elucidating the mechanism behind nicotine-mediated tumorigenesis.

Rationale and design of LUX-Head & Neck 1: a randomised, Phase III trial of afatinib versus methotrexate in patients with recurrent and/or metastatic head and neck squamous cell carcinoma who progressed after platinum-based therapy

BACKGROUND

Patients with recurrent and/or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) receiving platinum-based chemotherapy as their first-line treatment have a dismal prognosis, with a median overall survival (OS) of ~7 months. Methotrexate is sometimes used following platinum failure or in patients not fit enough for platinum therapy, but this agent has not demonstrated any OS improvement. Targeted therapies are a novel approach, with the EGFR-targeting monoclonal antibody cetuximab (plus platinum-based chemotherapy) approved in the US and Europe in the first-line R/M setting, and as monotherapy following platinum failure in the US. However, there is still a high unmet medical need for new treatments that improve outcomes in the second-line R/M setting following failure on first-line platinum-containing regimens. Afatinib, an irreversible ErbB family blocker, was recently approved for the first-line treatment of EGFR mutation-positive metastatic non-small cell lung cancer. Afatinib has also shown clinical activity similar to cetuximab in a Phase II proof-of-concept HNSCC trial. Based on these observations, the Phase III, LUX-Head & Neck 1 study is evaluating afatinib versus methotrexate in R/M HNSCC patients following progression on platinum-based chemotherapy in the R/M setting.

METHODS/DESIGN

Patients with progressive disease after one first-line platinum-based chemotherapy are randomised 2:1 to oral afatinib (starting dose 40 mg once daily) or IV methotrexate (starting dose 40 mg/m(2) once weekly) administered as monotherapy with best supportive care until progression or intolerable adverse events. Efficacy of afatinib versus methotrexate will be assessed in terms of progression-free survival (primary endpoint). Disease progression will be evaluated according to RECIST v1.1 by investigator and independent central review. Secondary endpoints include OS, tumour response and safety. Health-related quality of life and biomarker assessments will also be performed.

DISCUSSION

If the LUX-Head & Neck 1 trial meets its primary endpoint, it will demonstrate the ability of afatinib to elicit an improved treatment benefit versus a commonly used chemotherapy agent in the second-line treatment of R/M HNSCC patients who have failed on first-line platinum-based therapy, confirm the clinical efficacy of afatinib observed in the Phase II proof-of-concept study, and establish a new standard of care for this patient population.

Modulation of RTK by sEcad: a putative mechanism for oncogenicity in oropharyngeal SCCs

OBJECTIVE

Heightened levels of sEcad are found in the serum of patients with cancer and correlate with an unfavorable prognosis and later-stages of disease. In this study, we explored whether sEcad is elevated in human OPSCC specimens and FaDu cells. Additionally, we investigated sEcad-EGFR and sEcad-IGF-1R interactions and performed a functional analysis of sEcad in OPSCC cancers.

MATERIALS AND METHODS

sEcad, EGFR, and IGF-1R levels were examined in human OPSCC specimens and cells by immunoblotting. sEcad-EGFR and sEcad-IGF-1R interactions were examined by immunoprecipitation and immunoblot assays. Levels of sEcad on EGFR and IGF-1R pathway components were evaluated by IB. The effects of sEcad on OPSCC proliferation, migration, and invasion were assessed using standard cellular assays.

RESULTS

Statistical analysis demonstrated that sEcad levels were significantly higher in OPSCC primary tumors and cells compared with normal controls. IP studies indicated that sEcad associated with EGFR and IGF-1R, and addition of sEcad resulted in a statistically significant increase in downstream signaling. Finally, cell-based assays demonstrated enhanced sEcad-induced proliferation, migration, and invasion, which was blocked by EGFR and IGF-1R inhibitors.

CONCLUSIONS

These findings suggest that sEcad may play an important role in OPSCC oncogenicity via its interaction and activation of EGFR and IGF-1R.

Temporal characterization of lymphatic metastasis in an orthotopic mouse model of oral cancer

BACKGROUND

The overall mortality rate in cases of head and neck squamous cell carcinoma (HNSCC) has not improved over the past 30 years, mostly because of the high treatment failure rate among patients with regionally metastatic disease. To better understand the pathobiologic processes leading to lymphatic metastasis development, there is an urgent need for relevant animal models.

METHODS

HNSCC cell lines were implanted into the tongues of athymic nude mice. Histology, immunohistochemistry, and ex vivo 2-photon microscopy were used to evaluate tumor progress and spread.

RESULTS

Orthotopic xenografts of different HNSCC cell lines produced distinct patterns of survival, tumor histology, disease progression rate, and lymph node metastasis development. Remarkably, all injected cell types reached the lymph nodes within 24 hours after injection, but not all developed metastasis.

CONCLUSION

This orthotopic xenograft model closely mimics several characteristics of human cancer and could be extremely valuable for translational studies focusing on lymphatic metastasis development and pathobiology.

Indications and pitfalls of immunohistochemistry in head and neck cancer

Immunohistochemistry (IHC) has been employed in the differential diagnosis of tumors.

Objective

To assess the use of IHC in cases of head and neck tumor.

Method

This is a retrospective study of the cases included in the Cancer Registry of the institution.

Results

IHC was used in 76 (11%) of 704 pathology tests. Most cases were carcinomas (85.80%), and 83.66% of them were squamous cell carcinomas. All tests were done with diagnostic purposes. The most frequently used antibodies were 34BE12 (37.18%), AE1/AE3 (35.9%), 35BH11 (28.21%), CD45 (25.64%), CD20 (24.36%), CD30 (24.36%), CK7 (23.08%) and CD3 (23.08%).

Conclusions

IHC was used in 10.67% of the head and neck tumor cases submitted to pathology testing, mostly for carcinoma (5.26%). In the determination of squamous cell carcinoma, IHC accounted for 18.42% of all tumors.

Expanding the foundation for personalized medicine: implications and challenges for dentistry

Personalized medicine aims to individualize care based on a person's unique genetic, environmental, and clinical profile. Dentists and physicians have long recognized variations between and among patients, and have customized care based on each individual's health history, environment, and behavior. However, the sequencing of the human genome in 2003 and breakthroughs in regenerative medicine, imaging, and computer science redefined "personalized medicine" as clinical care that takes advantage of new molecular tools to facilitate highly precise health care based on an individual's unique genomic and molecular characteristics. Major investments in science bring a new urgency toward realizing the promise of personalized medicine; yet, many challenges stand in the way. In this article, we present an overview of the opportunities and challenges that influence the oral health community's full participation in personalized medicine. We highlight selected research advances that are solidifying the foundation of personalized oral health care, elaborate on their impact on dentistry, and explore obstacles toward their adoption into practice. It is our view that now is the time for oral health professionals, educators, students, researchers, and patients to engage fully in preparations for the arrival of personalized medicine as a means to provide quality, customized, and effective oral health care for all.