Genomic dissection of the epidermal growth factor receptor (EGFR)/PI3K pathway reveals frequent deletion of the EGFR phosphatase PTPRS in head and neck cancers

Reduced PTPRS expression promotes epithelial-mesenchymal transition of Schwann cells in NF1-related plexiform neurofibromas

Plexiform neurofibromas (PNFs) are a prevalent and severe phenotype associated with NF1, characterized by a high teratogenic rate and potential for malignant transformation. The growth and recurrence of PNFs are attributed to aberrant proliferation and migration of Nf1-deficient Schwann cells. Protein tyrosine phosphatase receptor S (PTPRS) is believed to modulate cell migration and invasion by inhibiting the EMT process in NF1-derived malignant peripheral nerve sheath tumors. Nevertheless, the specific role of PTPRS in NF1-derived PNFs remains to be elucidated. The study utilized the GEO database and tissue microarray to illustrate a decrease in PTPRS expression in PNF tissues, linked to tumor recurrence. Furthermore, the down- and over-expression of PTPRS in Nf1-deficient Schwann cell lines resulted in the changes of cell migration and EMT processes. Additionally, RTK assay and WB showed that PTPRS knockdown can promote EGFR expression and phosphorylation. The restoration of EMT processes disrupted by alterations in PTPRS levels in Schwann cells can be achieved through EGFR knockdown and EGFR inhibitor. Moreover, high EGFR expression has been significantly correlated with poor prognosis. These findings underscore the potential role of PTPRS as a tumor suppressor in the recurrence of PNF via the regulation of EGFR-mediated EMT processes, suggesting potential targets for future clinical interventions.

ECT2 promotes the occurrence and is a prognostic biomarker of head and neck squamous cell carcinoma

Background: Epithelial Cell Transforming Sequence 2 (ECT2) has been implicated in various tumorigenic processes, including proliferation, migration, and invasion. However, its specific role in head and neck squamous cell carcinoma (HNSCC) remains unclear. Methods: This study integrates transcriptomic and single-cell RNA sequencing (scRNA-seq) data to explore the potential role of ECT2 in HNSCC. Differential expression analysis, cell-based assays (including CCK-8 for proliferation, transwell for migration, invasion assays, and flow cytometry for apoptosis and cell cycle analysis), and enrichment analysis were employed to investigate ECT2 expression levels and its regulatory effects on cellular phenotypes. Additionally, Mendelian randomization analysis was utilized to identify genes causally related to HNSCC using publicly available Genome-Wide Association Study (GWAS) data. Results: ECT2 is highly expressed in HNSCC samples and its downregulation inhibits proliferation, migration, invasion, induces apoptosis, and affects the cell cycle transition in HSC-3 cells. Furthermore, differential analysis revealed significant differences in the immune microenvironment and drug sensitivity between high and low ECT2 expression groups. The pathways enriched in different groups include CCR and its related chemokines, as well as HLA in antigen presentation and immune response. There are also significant differences in the sensitivity to drugs such as bortezomib and dasatinib between the two groups. Prognostic models constructed from prognosis-related genes showed significant differences in prognosis between high and low-risk groups. Integration of scRNA-seq data identified Monocyte clusters as high-scoring cell clusters based on genes interacting with ECT2.Mendelian randomization analysis identified three genes (LGALS2, SLC11A1, and TKT) causally related to HNSCC within this cell cluster. Conclusion: The findings suggest that ECT2 overexpression is associated with the survival rate of HNSCC, indicating its potential as a prognostic biomarker for this malignancy.

The role of APOBEC3B in lung tumor evolution and targeted cancer therapy resistance

In this study, the impact of the apolipoprotein B mRNA-editing catalytic subunit-like (APOBEC) enzyme APOBEC3B (A3B) on epidermal growth factor receptor (EGFR)-driven lung cancer was assessed. A3B expression in EGFR mutant (EGFRmut) non-small-cell lung cancer (NSCLC) mouse models constrained tumorigenesis, while A3B expression in tumors treated with EGFR-targeted cancer therapy was associated with treatment resistance. Analyses of human NSCLC models treated with EGFR-targeted therapy showed upregulation of A3B and revealed therapy-induced activation of nuclear factor kappa B (NF-κB) as an inducer of A3B expression. Significantly reduced viability was observed with A3B deficiency, and A3B was required for the enrichment of APOBEC mutation signatures, in targeted therapy-treated human NSCLC preclinical models. Upregulation of A3B was confirmed in patients with NSCLC treated with EGFR-targeted therapy. This study uncovers the multifaceted roles of A3B in NSCLC and identifies A3B as a potential target for more durable responses to targeted cancer therapy.

Identification of Novel Candidate Genes for Familial Thyroid Cancer by Whole Exome Sequencing

Thyroid carcinoma (TC) can be classified as medullary (MTC) and non-medullary (NMTC). While most TCs are sporadic, familial forms of MTC and NMTC also exist (less than 1% and 3-9% of all TC cases, respectively). Germline mutations in RET are found in more than 95% of familial MTC, whereas familial NMTC shows a high degree of genetic heterogeneity. Herein, we aimed to identify susceptibility genes for familial NMTC and non-RET MTC by whole exome sequencing in 58 individuals belonging to 18 Spanish families with these carcinomas. After data analysis, 53 rare candidate segregating variants were identified in 12 of the families, 7 of them located in previously TC-associated genes. Although no common mutated genes were detected, biological processes regulating functions such as cell proliferation, differentiation, survival and adhesion were enriched. The reported functions of the identified genes together with pathogenicity and structural predictions, reinforced the candidacy of 36 of them, suggesting new loci related to TC and novel genotype-phenotype correlations. Therefore, our strategy provides clues to possible molecular mechanisms underlying familial forms of MTC and NMTC. These new molecular findings and clinical data of patients may be helpful for the early detection, development of tailored therapies and optimizing patient management.

KMT2D deficiency drives lung squamous cell carcinoma and hypersensitivity to RTK-RAS inhibition

Lung squamous cell carcinoma (LUSC) represents a major subtype of lung cancer with limited treatment options. KMT2D is one of the most frequently mutated genes in LUSC (>20%), and yet its role in LUSC oncogenesis remains unknown. Here, we identify KMT2D as a key regulator of LUSC tumorigenesis wherein Kmt2d deletion transforms lung basal cell organoids to LUSC. Kmt2d loss increases activation of receptor tyrosine kinases (RTKs), EGFR and ERBB2, partly through reprogramming the chromatin landscape to repress the expression of protein tyrosine phosphatases. These events provoke a robust elevation in the oncogenic RTK-RAS signaling. Combining SHP2 inhibitor SHP099 and pan-ERBB inhibitor afatinib inhibits lung tumor growth in Kmt2d-deficient LUSC murine models and in patient-derived xenografts (PDXs) harboring KMT2D mutations. Our study identifies KMT2D as a pivotal epigenetic modulator for LUSC oncogenesis and suggests that KMT2D loss renders LUSC therapeutically vulnerable to RTK-RAS inhibition.

IQGAP1 and RNA Splicing in the Context of Head and Neck via Phosphoproteomics

IQGAP1 (IQ motif-containing GTPase-activating protein 1) scaffolds several signaling pathways in mammalian cells that are implicated in carcinogenesis, including the RAS and PI3K pathways that involve multiple protein kinases. IQGAP1 has been shown to promote head and neck squamous cell carcinoma (HNSCC); however, the underlying mechanism(s) remains unclear. Here, we report a mass spectrometry-based analysis identifying differences in phosphorylation of cellular proteins in vivo and in vitro in the presence or absence of IQGAP1. By comparing the esophageal phosphoproteome profiles between Iqgap1+/+ and Iqgap1-/- mice, we identified RNA splicing as one of the most altered cellular processes. Serine/arginine-rich splicing factor 6 (SRSF6) was the protein with the most downregulated levels of phosphorylation in Iqgap1-/- tissue. We confirmed that the absence of IQGAP1 reduced SRSF6 phosphorylation both in vivo and in vitro. We then expanded our analysis to human normal oral keratinocytes. Again, we found factors involved in RNA splicing to be highly altered in the phosphoproteome profile upon genetic disruption of IQGAP1. Both the Clinical Proteomic Tumor Analysis Consortium (CPTAC) and the Cancer Genome Atlas (TCGA) data sets indicate that phosphorylation of splicing-related proteins is important in HNSCC prognosis. The Biological General Repository for Interaction Datasets (BioGRID) repository also suggested multiple interactions between IQGAP1 and splicing-related proteins. Based on these collective observations, we propose that IQGAP1 regulates the phosphorylation of splicing proteins, which potentially affects their splicing activities and, therefore, contributes to HNSCC. Raw data are available from the MassIVE database with identifier MSV000087770.

High expression of protein tyrosine phosphatase receptor S (PTPRS) is an independent prognostic marker for cholangiocarcinoma

Cholangiocarcinoma (CCA) is an aggressive tumor of the bile duct with a high rate of mortality. Lymph node metastasis is an important factor facilitating the progression of CCA. A reliable biomarker for diagnosis, progression status, or prognosis of CCA is still lacking. To identify a novel and reliable biomarker for diagnosis/prognosis of CCA, liquid chromatography-mass spectrometry and tandem mass spectrometry (LC-MS/MS) in combination with bioinformatics analysis were applied for the representative serum samples of patients with CCA. The proteome results showed that protein tyrosine phosphatase receptor S (PTPRS) had the highest potential candidate. Then, a dot blot assay was used to measure the level of serum PTPRS in patients with CCA (n = 80), benign biliary disease patients (BBD; n = 39), and healthy controls (HC; n = 55). PTPRS level of CCA sera (14.38 ± 9.42 ng/ml) was significantly higher than that of BBD (10.7 ± 5.05 ng/ml) or HC (6 ± 3.73 ng/ml) (P < 0.0001). PTPRS was associated with serum albumin (P = 0.028), lymph node metastasis (P = 0.038), and the survival time of patients (P = 0.011). Using a log-rank test, higher serum PTPRS level was significantly (P = 0.031) correlated with a longer overall survival time of patients with CCA, and PTPRS was an independent prognostic marker for CCA superior to carbohydrate antigen 19-9 (CA19-9), carcinoembryonic antigen (CEA) or alkaline phosphatase (ALP). High expression of PTPRS could be a good independent prognostic marker for CCA.

Molecular Pathways and Druggable Targets in Head and Neck Squamous Cell Carcinoma

Head and neck cancers are a heterogeneous group of neoplasms, affecting an ever increasing global population. Despite advances in diagnostic technology and surgical approaches to manage these conditions, survival rates have only marginally improved and this has occurred mainly in developed countries. Some improvements in survival, however, have been a result of new management and treatment approaches made possible because of our ever-increasing understanding of the molecular pathways triggered in head and neck oncogenesis, and the growing understanding of the abundant heterogeneity of this group of cancers. Some important pathways are common to other solid tumours, but their impact on reducing the burden of head and neck disease has been less than impressive. Other less known and little-explored pathways may hold the key to the development of potential druggable targets. The extensive work carried out over the last decade, mostly utilising next generation sequencing has opened up the development of many novel approaches to head and neck cancer treatment. This paper explores our current understanding of the molecular pathways of this group of tumours and outlines associated druggable targets which are deployed as therapeutic approaches in head and neck oncology with the ultimate aim of improving patient outcomes and controlling the personal and economic burden of head and neck cancer.

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.

Worldwide prevalence of PI3K-AKT-mTOR pathway mutations in head and neck cancer: A systematic review and meta-analysis

A systematic review (SR) and meta-analysis were conducted to determine the prevalence of PI3K-AKT-mTOR signaling pathway mutations in patients with head and neck cancer (HNC). Overall, 105 studies comprising 8630 patients and 1306 mutations were selected. The estimated mutations prevalence was 13 % for PIK3CA (95 % confidence interval [CI] = 11-14; I² = 82 %; p < 0.0001), 4% for PTEN (95 % CI = 3-5; I² = 55 %; p < 0.0001), 3% for MTOR (95 % CI = 2-4; I² = 5%; p = 0.40), and 2% for AKT (95 % CI = 1-2; I² = 50 %; p = 0.0001). We further stratified the available data of the participants according to risk factors and tumor characteristics, including HPV infection, tobacco use, alcohol exposure, TNM stage, and histological tumor differentiation, and performed subgroup analysis. We identified significant associations between PI3K-AKT-mTOR pathway-associated mutations and advanced TNM stage (odds ratio [OR] = 0.20; 95 % CI = 0.09-0.44; I² = 71 %; p = 0.0001) and oropharyngeal HPV-positive tumors and PIK3CA mutations (OR = 17.48; 95 % CI = 4.20-72.76; I² = 69 %; p < 0.0002). No associations were found between alcohol and tobacco exposure, and tumor differentiation grade. This SR demonstrated that the PI3K-AKT-mTOR pathway emerges as a potential prognostic factor and could offer a molecular basis for future studies on therapeutic targeting in HNC patients.

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.

The PI3K/Akt/mTORC signaling axis in head and neck squamous cell carcinoma: Possibilities for therapeutic interventions either as single agents or in combination with conventional therapies

The latest advances in the sequencing methods in head and neck squamous cell carcinoma (HNSCC) tissues have revolutionized our understanding of the disease by taking off the veil from the most frequent genetic alterations in the components of the oncogenic pathways. Among all the identified alterations, aberrancies in the genes attributed to the phosphoinositide 3-kinases (PI3K) axis have attracted special attention as they were altered in more than 90% of the tissues isolated from HNSCC patients. In fact, the association between these aberrancies and the increased risk of cancer metastasis suggested this axis as an "Achilles Heel" of HNSCC, which may be therapeutically targeted. The results of the clinical trials investigating the therapeutic potential of the inhibitors targeting the components of the PI3K axis in the treatment of HNSCC patients, either alone or in a combined-modal strategy, opened a new chapter in the treatment strategy of this malignancy. The present study aimed to review the importance of the PI3K axis in the pathogenesis of HNSCC and also provide a piece of information about the breakthroughs and challenges of PI3K inhibitors in the therapeutic strategies of the disease.

Mini-review: Role of the PI3K/Akt pathway and tyrosine phosphatases in Alzheimer's disease susceptibility

A variety of findings from in vitro experiments and animal models support the hypothesis that one contribution to pathogenesis in Alzheimer's disease (AD) is enhanced phosphorylation of tau protein, which may be triggered by amyloid β (Aβ) and mediated by impaired activity of the PI3K/Akt signaling pathway. A number of tyrosine phosphatases act to reduce PI3K/Akt activity, and inhibition of tyrosine phosphatases is protective against Aβ toxicity in cell cultures and whole animals. Results from analysis of exome sequenced late onset AD cases and controls similarly show that rare coding variants predicted to damage PI3K functioning increase AD risk, whereas those which are predicted to damage genes for tyrosine phosphatase genes are protective. Taken together, these results support the proposition that tyrosine phosphatase antagonists might be trialed as therapeutic agents to protect against the development of AD.

Down-regulation of lncRNA HCG11 promotes cell proliferation of oral squamous cell carcinoma through sponging miR-455-5p

BACKGROUND

As a type of head and neck squamous cell carcinoma (HNSCC), oral squamous cell carcinoma (OSCC) has a high incidence and low survival rate. Frequent deletion of protein tyrosine phosphatase receptor type sigma (PTPRS) has been found in HNSCC. Long non-coding RNA (lncRNA) HCG11 and miR-455-5p have been reported to be involved in several cancers, in which miR-455-5p was found to be up-regulated in the OSCC. However, the role of HCG11 in OSCC development is still unclear.

METHODS

Several co-transfection systems were established to explore the regulation of HCG11 on OSCC cells. Cell proliferation was evaluated by the MTT assay, flow cytometry of cell cycle distribution, immunofluorescence of Ki67 and western blotting. A dual luciferase reporter assay was performed to verify the binding effects of miR-455-5p on HCG11 and PTPRS. The role of HCG11 knockdown in OSCC cell growth was also confirmed by nude mouse tumorigenicity assay in vivo.

RESULTS

Knockdown of HCG11 increased OSCC cell proliferation, as indicated by enhanced cell vitalities over time, increased G1/S transition and Ki67 levels. Furthermore, lncRNA HCG11 was shown to negatively regulate miR-455-5p and miR-455-5p targeted PTPRS directly to affect its downstream indicators, which can further modulate OSCC cell proliferation and growth. The results obtained in vivo confirmed that HCG11 knockdown promoted OSCC cell growth.

CONCLUSIONS

The lncRNA HCG11/miR-R-455-5p axis can be considered as an upstream signalling circuit of PTPRS with respect to regulating its activity and downstream pathways to further influence the progression of OSCC. This finding may provide a novel RNA-based therapeutic target for OSCC treatment.

A highway to carcinogenesis: the role of IQGAP1, a signaling scaffolding protein, in head and neck cancer development

Head and neck squamous cell carcinoma (HNSCC) is the sixth most frequent cancer worldwide. One of the most critical signaling pathways in HNSCC is the Epidermal Growth Factor Receptor/ Phosphatidylinositol 3-Kinase (EGFR/PI3K) pathway. IQ motif-containing GTPase- activating protein 1 (IQGAP1), a protein upregulated in multiple types of cancer, acts as a scaffold for this pathway and others implicated in cancer. IQGAP1 is overexpressed in HNSCCs, and its overexpression correlates with poorer prognosis in HNSCC patients, indicating that IQGAP1 might be important in HNSCC development. Here, we summarized our recent demonstrating a role of IQGAP1 in promoting HNSCC, at least in part, by scaffolding the EGFR/PI3K signaling pathway.

PIK3CA and p53 Mutations Promote 4NQO-Initated Head and Neck Tumor Progression and Metastasis in Mice

The PI3K signaling pathway is frequently mutated in head and neck squamous cell carcinoma (HNSCC), often via gain-of-function (GOF) mutations in the PIK3CA gene. Here, we present novel genetically engineered mouse models (GEMM) carrying a GOF allele Loxp-STOP-Loxp(LSL)-PIK3CAH1047R (E20) alone or in combination with heterozygous LSL-p53+/R172H (p53) mutation with tissue-specific expression to interrogate the role of oncogenic PIK3CA in transformation of upper aerodigestive track epithelium. We demonstrated that the GOF PIK3CA mutation promoted progression of 4-nitroquinoline 1-oxide-induced oral squamous cell carcinoma (OSCC) in both E20 single mutant and E20/p53 double mutant mice, with frequent distal metastasis detected only in E20/p53 GEMM. Similar to in human OSCC, loss of p16 was associated with progression of OSCC in these mice. RNA-seq analyses revealed that among the common genes differentially expressed in primary OSCC cell lines derived from E20, p53, and E20/p53 GEMMs compared with those from the wild-type mice, genes associated with proliferation and cell cycle were predominantly represented, which is consistent with the progressive loss of p16 detected in these GEMMs. Importantly, all of these OSCC primary cell lines exhibited enhanced sensitivity to BYL719 and cisplatin combination treatment in comparison with cisplatin alone in vitro and in vivo, regardless of p53 and/or p16 status. Given the prevalence of mutations in p53 and the PI3K pathways in HNSCC in conjunction with loss of p16 genetically or epigenetically, this universal increased sensitivity to cisplatin and BYL719 combination therapy in cancer cells with PIK3CA mutation represents an opportunity to a subset of patients with HNSCC. IMPLICATIONS: Our results suggest that combination therapy of cisplatin and PI3K inhibitor may be worthy of consideration in patients with HNSCC with PIK3CA mutation.

Weighted burden analysis of exome-sequenced late-onset Alzheimer's cases and controls provides further evidence for a role for PSEN1 and suggests involvement of the PI3K/Akt/GSK-3β and WNT signalling pathways

Previous studies have implicated common and rare genetic variants as risk factors for late-onset Alzheimer's disease (LOAD). Here, weighted burden analysis was applied to over 10,000 exome-sequenced subjects from the Alzheimer's Disease Sequencing Project. Analyses were carried out to investigate whether rare variants predicted to have a functional effect within a gene were more commonly seen in cases or in controls. Confirmatory results were obtained for TREM2, ABCA7, and SORL1. Additional support was provided for PSEN1 (p = 0.0002), which previously had been only weakly implicated in LOAD. There was suggestive evidence that functional variants in PIK3R1, WNT7A, C1R, and EXOC5 might increase risk and that variants in TIAF1 and/or NDRG2 might have a protective effect. Overall, there was strong evidence (p = 5 × 10-6 ) that variants in tyrosine phosphatase genes reduce the risk of developing LOAD. Because PIK3R1 variants are expected to impair PI3K/Akt/GSK-3β signalling while variants in tyrosine phosphatase genes would enhance it, these findings are in line with those from animal models, suggesting that this pathway is protective against Alzheimer's disease.

PTPRS drives adaptive resistance to MEK/ERK inhibitors through SRC

PTPRS is the most commonly mutated receptor tyrosine phosphatase in colorectal cancer (CRC). PTPRS has been shown to directly affect ERK and regulate its activation and nuclear localization. Here we identify that PTPRS may play a significant role in developing adaptive resistance to MEK/ERK inhibitors (MEKi/ERKi) through SRC activation. Moreover, we demonstrate a new clinical approach to averting adaptive resistance through the use of the SRC inhibitor, dasatinib. Our data suggest the potential for dasatinib to enhance the efficacy of MEKi and ERKi by preventing adaptive resistance pathways operating through SRC.

mTOR Signaling in Cancer and mTOR Inhibitors in Solid Tumor Targeting Therapy

The mammalian or mechanistic target of rapamycin (mTOR) pathway plays a crucial role in regulation of cell survival, metabolism, growth and protein synthesis in response to upstream signals in both normal physiological and pathological conditions, especially in cancer. Aberrant mTOR signaling resulting from genetic alterations from different levels of the signal cascade is commonly observed in various types of cancers. Upon hyperactivation, mTOR signaling promotes cell proliferation and metabolism that contribute to tumor initiation and progression. In addition, mTOR also negatively regulates autophagy via different ways. We discuss mTOR signaling and its key upstream and downstream factors, the specific genetic changes in the mTOR pathway and the inhibitors of mTOR applied as therapeutic strategies in eight solid tumors. Although monotherapy and combination therapy with mTOR inhibitors have been extensively applied in preclinical and clinical trials in various cancer types, innovative therapies with better efficacy and less drug resistance are still in great need, and new biomarkers and deep sequencing technologies will facilitate these mTOR targeting drugs benefit the cancer patients in personalized therapy.

Targeting the BDNF/TrkB pathway for the treatment of tumors

Neurotrophins are a family of growth factors that regulate neural survival, development, function and plasticity in the central and the peripheral nervous system. There are four neurotrophins: nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and NT-4. Among them, BDNF is the most studied due to its high expression in the brain. Over the past two decades, BDNF and its receptor tropomyosin receptor kinase B (TrkB) have been reported to be upregulated in a wide range of tumors. This activated signal stimulates a series of downstream pathways, including phosphoinositide 3-kinase/protein kinase B, Ras-Raf-mitogen activated protein kinase kinase-extracellular signal-regulated kinases, the phospholipase-C-γ pathway and the transactivation of epidermal growth factor receptor. Activation of these signaling pathways induces oncogenic effects by increasing cancer cell growth, proliferation, survival, migration and epithelial to mesenchymal transition, and decreasing anoikis, relapse and chemotherapeutic sensitivity. The present review summarizes recent findings to discuss the role of BDNF in tumors, the underlying molecular mechanism, targeting Trk receptors for treatment of cancers and its potential risk.

The impact of phosphatases on proliferative and survival signaling in cancer

The dynamic and stringent coordination of kinase and phosphatase activity controls a myriad of physiologic processes. Aberrations that disrupt the balance of this interplay represent the basis of numerous diseases. For a variety of reasons, early work in this area portrayed kinases as the dominant actors in these signaling events with phosphatases playing a secondary role. In oncology, these efforts led to breakthroughs that have dramatically altered the course of certain diseases and directed vast resources toward the development of additional kinase-targeted therapies. Yet, more recent scientific efforts have demonstrated a prominent and sometimes driving role for phosphatases across numerous malignancies. This maturation of the phosphatase field has brought with it the promise of further therapeutic advances in the field of oncology. In this review, we discuss the role of phosphatases in the regulation of cellular proliferation and survival signaling using the examples of the MAPK and PI3K/AKT pathways, c-Myc and the apoptosis machinery. Emphasis is placed on instances where these signaling networks are perturbed by dysregulation of specific phosphatases to favor growth and persistence of human cancer.

PTPRS Regulates Colorectal Cancer RAS Pathway Activity by Inactivating Erk and Preventing Its Nuclear Translocation

Colorectal cancer (CRC) growth and progression is frequently driven by RAS pathway activation through upstream growth factor receptor activation or through mutational activation of KRAS or BRAF. Here we describe an additional mechanism by which the RAS pathway may be modulated in CRC. PTPRS, a receptor-type protein tyrosine phosphatase, appears to regulate RAS pathway activation through ERK. PTPRS modulates ERK phosphorylation and subsequent translocation to the nucleus. Native mutations in PTPRS, present in ~10% of CRC, may reduce its phosphatase activity while increasing ERK activation and downstream transcriptional signaling.

The Roles of Protein Tyrosine Phosphatases in Hepatocellular Carcinoma

The protein tyrosine phosphatase (PTP) family is involved in multiple cellular functions and plays an important role in various pathological and physiological processes. In many chronic diseases, for example cancer, PTP is a potential therapeutic target for cancer treatment. In the last two decades, dozens of PTP inhibitors which specifically target individual PTP molecules were developed as therapeutic agents. Hepatocellular carcinoma (HCC) is one of the most common malignant tumors and is the second most lethal cancer worldwide due to a lack of effective therapies. Recent studies have unveiled both oncogenic and tumor suppressive functions of PTP in HCC. Here, we review the current knowledge on the involvement of PTP in HCC and further discuss the possibility of targeting PTP in HCC.

CoGAPS matrix factorization algorithm identifies transcriptional changes in AP-2alpha target genes in feedback from therapeutic inhibition of the EGFR network

Patients with oncogene driven tumors are treated with targeted therapeutics including EGFR inhibitors. Genomic data from The Cancer Genome Atlas (TCGA) demonstrates molecular alterations to EGFR, MAPK, and PI3K pathways in previously untreated tumors. Therefore, this study uses bioinformatics algorithms to delineate interactions resulting from EGFR inhibitor use in cancer cells with these genetic alterations. We modify the HaCaT keratinocyte cell line model to simulate cancer cells with constitutive activation of EGFR, HRAS, and PI3K in a controlled genetic background. We then measure gene expression after treating modified HaCaT cells with gefitinib, afatinib, and cetuximab. The CoGAPS algorithm distinguishes a gene expression signature associated with the anticipated silencing of the EGFR network. It also infers a feedback signature with EGFR gene expression itself increasing in cells that are responsive to EGFR inhibitors. This feedback signature has increased expression of several growth factor receptors regulated by the AP-2 family of transcription factors. The gene expression signatures for AP-2alpha are further correlated with sensitivity to cetuximab treatment in HNSCC cell lines and changes in EGFR expression in HNSCC tumors with low CDKN2A gene expression. In addition, the AP-2alpha gene expression signatures are also associated with inhibition of MEK, PI3K, and mTOR pathways in the Library of Integrated Network-Based Cellular Signatures (LINCS) data. These results suggest that AP-2 transcription factors are activated as feedback from EGFR network inhibition and may mediate EGFR inhibitor resistance.

Genetically-defined novel oral squamous cell carcinoma cell lines for the development of molecular therapies

Emerging biological and translational insights from large sequencing efforts underscore the need for genetically-relevant cell lines to study the relationships between genomic alterations of tumors, and therapeutic dependencies. Here, we report a detailed characterization of a novel panel of clinically annotated oral squamous cell carcinoma (OSCC) cell lines, derived from patients with diverse ethnicity and risk habits. Molecular analysis by RNAseq and copy number alterations (CNA) identified that the cell lines harbour CNA that have been previously reported in OSCC, for example focal amplications in 3q, 7p, 8q, 11q, 20q and deletions in 3p, 5q, 8p, 18q. Similarly, our analysis identified the same cohort of frequently mutated genes previously reported in OSCC including TP53, CDKN2A, EPHA2, FAT1, NOTCH1, CASP8 and PIK3CA. Notably, we identified mutations (MLL4, USP9X, ARID2) in cell lines derived from betel quid users that may be associated with this specific risk factor. Gene expression profiles of the ORL lines also aligned with those reported for OSCC. By focusing on those gene expression signatures that are predictive of chemotherapeutic response, we observed that the ORL lines broadly clustered into three groups (cell cycle, xenobiotic metabolism, others). The ORL lines noted to be enriched in cell cycle genes responded preferentially to the CDK1 inhibitor RO3306, by MTT cell viability assay. Overall, our in-depth characterization of clinically annotated ORL lines provides new insight into the molecular alterations synonymous with OSCC, which can facilitate in the identification of biomarkers that can be used to guide diagnosis, prognosis, and treatment of OSCC.

Tumor suppressive protein phosphatases in human cancer: Emerging targets for therapeutic intervention and tumor stratification

Aberrant protein phosphorylation is one of the hallmarks of cancer cells, and in many cases a prerequisite to sustain tumor development and progression. Like protein kinases, protein phosphatases are key regulators of cell signaling. However, their contribution to aberrant signaling in cancer cells is overall less well appreciated, and therefore, their clinical potential remains largely unexploited. In this review, we provide an overview of tumor suppressive protein phosphatases in human cancer. Along their mechanisms of inactivation in defined cancer contexts, we give an overview of their functional roles in diverse signaling pathways that contribute to their tumor suppressive abilities. Finally, we discuss their emerging roles as predictive or prognostic markers, their potential as synthetic lethality targets, and the current feasibility of their reactivation with pharmacologic compounds as promising new cancer therapies. We conclude that their inclusion in clinical practice has obvious potential to significantly improve therapeutic outcome in various ways, and should now definitely be pushed forward.

The Diacetyl-Exposed Human Airway Epithelial Secretome: New Insights into Flavoring-Induced Airways Disease

Bronchiolitis obliterans (BO) is an increasingly important lung disease characterized by fibroproliferative airway lesions and decrements in lung function. Occupational exposure to the artificial food flavoring ingredient diacetyl, commonly used to impart a buttery flavor to microwave popcorn, has been associated with BO development. In the occupational setting, diacetyl vapor is first encountered by the airway epithelium. To better understand the effects of diacetyl vapor on the airway epithelium, we used an unbiased proteomic approach to characterize both the apical and basolateral secretomes of air-liquid interface cultures of primary human airway epithelial cells from four unique donors after exposure to an occupationally relevant concentration (∼1,100 ppm) of diacetyl vapor or phosphate-buffered saline as a control on alternating days. Basolateral and apical supernatants collected 48 h after the third exposure were analyzed using one-dimensional liquid chromatography tandem mass spectrometry. Paired t tests adjusted for multiple comparisons were used to assess differential expression between diacetyl and phosphate-buffered saline exposure. Of the significantly differentially expressed proteins identified, 61 were unique to the apical secretome, 81 were unique to the basolateral secretome, and 11 were present in both. Pathway enrichment analysis using publicly available databases revealed that proteins associated with matrix remodeling, including degradation, assembly, and new matrix organization, were overrepresented in the data sets. Similarly, protein modifiers of epidermal growth factor receptor signaling were significantly altered. The ordered changes in protein expression suggest that the airway epithelial response to diacetyl may contribute to BO pathogenesis.

Prevalence of EGFR Tyrosine Kinase Domain Mutations in Head and Neck Squamous Cell Carcinoma: Cohort Study and Systematic Review

BACKGROUND

Mutations in the epidermal growth factor receptor (EGFR) tyrosine kinase domain (TKD) are associated with response and resistance to targeted therapy. The EGFR mutation status in patients with advanced oral and oropharyngeal squamous cell carcinoma (OOSCC) was evaluated. A systematic literature review was undertaken to summarize current evidence and estimate the overall prevalence of EGFR TKD mutations in patients with head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

Genomic DNA was extracted from formalin-fixed, paraffin-embedded tumor samples of 113 patients with OOSCC. Pyrosequencing was performed to investigate mutations in EGFR exons 18 to 21. Medline databases were searched for relevant studies. Studies reporting mutations in the EGFR TKD in HNSCC were eligible for inclusion in the systematic review.

RESULTS

No mutations in the EGFR TKD were observed in 113 samples of OOSCC. A total of 53 eligible studies were included in the systematic review. In total, from the review, 117 patients harboring a total of 159 EGFR TKD mutations were reported among 4122 patients with HNSCC. The overall prevalence of EGFR TKD mutations in HNSCC was 2.8%.

CONCLUSION

Large-scale studies are warranted to provide further evidence regarding the mutation status of EGFR in patients with HNSCC.

Knockdown of HPIP Inhibits the Proliferation and Invasion of Head-and-Neck Squamous Cell Carcinoma Cells by Regulating PI3K/Akt Signaling Pathway

Hematopoietic pre-B-cell leukemia transcription factor (PBX)-interacting protein (HPIP/PBXIP1) is a corepressor for the transcription factor PBX. Previous studies showed that HPIP is frequently overexpressed in many tumors. However, the role of HPIP in head-and-neck squamous cell carcinoma (HNSCC) has not yet been determined. Thus, we decided to investigate the effects and mechanisms of HPIP in HNSCC. Our results demonstrated that HPIP is highly expressed in human HNSCC cell lines and provides the first evidence that knockdown of HPIP obviously inhibits proliferation and migration/invasion in HNSCC cells in vitro, as well as inhibits tumor growth in vivo. Furthermore, knockdown of HPIP significantly inhibits the expression of p-PI3K and p-Akt in human HNSCC cells. In conclusion, our study demonstrated that knockdown of HPIP significantly inhibits the proliferation and migration/invasion of HNSCC cells by suppressing the PI3K/Akt signaling pathway. Therefore, HPIP may be a novel potential therapeutic target for the treatment of HNSCC.

Clinical benefit of nanoparticle albumin-bound-paclitaxel in recurrent/metastatic head and neck squamous cell carcinoma resistant to cremophor-based paclitaxel or docetaxel

The clinical benefit of nab-paclitaxel monotherapy for recurrent/metastatic head and neck squamous cell carcinoma (RM-HNSCC) that progressed on other taxanes (cremophor-based paclitaxel or docetaxel) is unknown. A retrospective analysis of patients treated at a single institution with nab-paclitaxel for taxane-resistant RM-HNSCC. The exploratory hypothesis was that nab-paclitaxel would result in clinical benefit (tumor response) in patients with taxane-resistant RM-HNSCC. Twelve patients who were treated with nab-paclitaxel monotherapy for taxane-resistant RM-HNSCC and met all eligibility criteria were identified. The majority of patients (n = 9; 75%) received three or more lines of therapy for RM-HNSCC. All patients had platin-resistant, and ten patients (83%) had cetuximab-resistant disease. Patients had RM-HNSCC that progressed on cremophor-based paclitaxel (8), docetaxel (1), or both (3). With prior taxane, the best tumor response was partial (PR) in 4 patients (33%), stable (SD) in 3 (25%), and progression in 5 (42%). The median time-to-progression (TTP) with prior taxane was 1.7 (range 0.7-9.0) months. The median interval from last dose of taxane to first dose of nab-paclitaxel was 3 (0.7-31.3) months. With nab-paclitaxel, tumor response occurred in two patients (17%; PR in both) and disease control (PR and SD) occurred in five (42%). Median TTP with nab-paclitaxel was 2.1 months (range 0.6-6.2), and median overall survival was 4.9 months (range 1.9-13.5). nab-Paclitaxel provided clinical benefit in some patients with taxane-resistant RM-HNSCC. The median TTP with nab-paclitaxel and with prior taxane were similar. This exploratory observation warrants further investigation in prospective studies.

Novel mutations of PIK3CA gene in head and neck squamous cell carcinoma

BACKGROUND

HNSCC is the sixth most common human cancer globally. In Saudi Arabia, HNSCC accounts for seven percent of all newly diagnosed cancer cases. The PIK3CA is one of the most commonly mutated oncogene in human malignancies, including HNSCC.

OBJECTIVE

The objective of this study is to identify mutations in exon 9 and exon 20 of the PIK3CA gene among Saudi HNSCC patients, determine the frequency of these mutations and correlate with clinical and pathological findings.

METHODS

Histopathologically confirmed paraffin embedded HNSCC tumor tissues from 48 patients were obtained. Capillary sequencing method was used to sequence exons 9 and 20 of the PIK3CA gene. Concurrently, the expression analysis of the PIK3CA and PTEN genes were performed using real-time PCR.

RESULTS

Sixty percent of the samples studied were of pharyngeal cancer. A total of seven mutations were identified in exons 9 and 20 of the PIK3CA gene in 14 HNSCC tumor tissue specimens. The seven mutations encompassed one hot spot mutation E542K, a common mutation T1025T and the five novel mutation comprising three missense and two silent mutations. Interestingly, eight out of the 14 samples with a mutation were of patients with pharyngeal cancer.

CONCLUSION

PIK3CA gene plays a crucial role in carcinogenesis in general and HNSCC in particular. The identification of five novel mutations suggest that Saudis may have different frequencies of somatic genetic alterations that may influence HNSCC compared to other populations.

nab-Paclitaxel, cisplatin, and 5-fluorouracil followed by concurrent cisplatin and radiation for head and neck squamous cell carcinoma

OBJECTIVES

We previously reported the efficacy of nab-paclitaxel added to cisplatin, 5-FU, and cetuximab (APF-C) followed by concurrent high dose bolus cisplatin and radiation therapy (CRT) in patients with locally advanced head and neck squamous cell carcinoma (HNSCC). In this phase II trial, we determined the efficacy of APF (without cetuximab) followed by CRT in similar patients.

MATERIALS AND METHODS

Eligible patients had stage III-IV oropharynx (OP), larynx, or hypopharynx SCC and adequate organ function and performance status. T1 tumors were excluded. Patients were treated with three cycles of APF followed by CRT. Efficacy endpoints included two-year disease-specific survival (DSS), progression-free survival (PFS), overall survival (OS), and relapse rate.

RESULTS

Thirty patients were enrolled. Most patients were smokers (77%) with bulky T3/4 (73%) and N2/3 (83%) tumors. Analyses were stratified for human papilloma virus (HPV) status: HPV-related OPSCC (n=17; 57%) and HPV-unrelated HNSCC (n=13; 43%). With a minimum follow-up of 21months, relapse occurred in 1 (3%) patient. Two-year DSS was 94% in HPV-related OPSCC and 100% in HPV-unrelated HNSCC. Two-year PFS was 94% in HPV-related OPSCC and 100% in HPV-unrelated HNSCC. Two-year OS was 94% in HPV-related OPSCC and 92% in HPV-unrelated HNSCC. Causes of death were relapse (1), treatment-related mortality (1), and co-morbidity (1). Two patients with HPV-unrelated HNSCC treated with APF declined CRT and remained free of relapse at 36 and 28months of follow-up.

CONCLUSION

This phase II trial demonstrated favorable two-year DSS, PFS, and OS and a low relapse rate in HPV-unrelated HNSCC and HPV-related OPSCC treated with APF followed by CRT.

Molecular pathways in head and neck cancer: EGFR, PI3K, and more

The treatment of head and neck squamous cell carcinoma (HNSCC) is set to undergo rapid changes, as novel treatment targets informed by genomic profiling and novel molecularly targeted therapies continue to make strides. In this review we provide an overview of the latest developments regarding (1) EGFR targeting for HNSCC, (2) PI3K as a novel treatment target, and (3) newly described key genetic events in HNSCC such as NOTCH1 mutations and emerging candidate targets including ALK1 and hedgehog. The first molecular targeting strategy to demonstrate a survival advantage for patients with HNSCC has emerged in the context of EGFR biology. Cetuximab remains the only U.S. Food and Drug Administration (FDA)-approved targeted therapy available for HNSCC, but EGFR as a target has not been individualized in this disease. The PI3K-AKT pathway is downstream of EGFR and is emerging as potentially one of the most important pathways in HNSCC. PIK3CA is the most frequently mutated oncogene for HNSCC (approximately 20%) and may play a role for both HPV-negative and HPV-positive tumors. Multiple therapeutic strategies targeting PI3K are being explored, and multiple agents either alone or in combination are in development. NOTCH1 is a key tumor suppressor gene and its genetic alterations lead to abnormal pathway activation. ALK1 is a novel target involved in angiogenesis, and efficacy in patients with HNSCC was documented in an early inhibitor trial. The hedgehog pathway modulates EGFR dependence and epithelial to mesenchymal transition (EMT), a key invasion and drug-resistance mechanism in HNSCC.

Unbiased identification of substrates of protein tyrosine phosphatase ptp-3 in C. elegans

The leukocyte antigen related (LAR) family of receptor-like protein tyrosine phosphatases has three members in humans - PTPRF, PTPRD and PTPRS - that have been implicated in diverse processes including embryonic development, inhibition of cell growth and axonal guidance. Mutations in the LAR family are associated with developmental defects such as cleft palate as well as various cancers including breast, neck, lung, colon and brain. Although this family of tyrosine phosphatases is important for many developmental processes, little is known of their substrates. This is partially due to functional redundancy within the LAR family, as deletion of a single gene in the LAR family does not have an appreciable phenotype, but a dual knockout is embryonically lethal in mouse models. To circumvent the inability to knockout multiple members of the LAR family in mouse models, we used a knockout of ptp-3, which is the only known ortholog of the LAR family in Caenorhabditis elegans and allows for the study of the LAR family at the organismal level. Using SILAC-based quantitative phosphoproteomics, we identified 255 putative substrates of ptp-3, which included four of the nine known annotated substrates of the LAR family. A motif analysis of the identified phosphopeptides allowed for the determination of sequences that appear to be preferentially dephosphorylated. Finally, we discovered that kinases were overrepresented in the list of identified putative substrates and tyrosine residues whose phosphorylation is known to increase kinase activity were dephosphorylated by ptp-3. These data are suggestive of ptp-3 as a potential negative regulator of several kinase families, such as the mitogen activated kinases (MAPKs), and multiple tyrosine kinases including FER, MET, and NTRK2.

Overexpression of PIK3CA in murine head and neck epithelium drives tumor invasion and metastasis through PDK1 and enhanced TGFβ signaling

Head and neck squamous cell carcinoma (HNSCC) patients have a poor prognosis, with invasion and metastasis as major causes of mortality. The phosphatidylinositol 3-kinase (PI3K) pathway regulates a wide range of cellular processes crucial for tumorigenesis, and PIK3CA amplification and mutation are among the most common genetic alterations in human HNSCC. Compared to the well-documented roles of the PI3K pathway in cell growth and survival, the roles of the PI3K pathway in tumor invasion and metastasis have not been well delineated. We generated a PIK3CA-genetically engineered mouse model (PIK3CA-GEMM) in which wildtype PIK3CA is overexpressed in head and neck epithelium. Although PIK3CA overexpression alone was not sufficient to initiate HNSCC formation, it significantly increased tumor susceptibility in an oral-carcinogenesis mouse model. PIK3CA overexpression in mouse oral epithelium increased tumor invasiveness and metastasis by increasing epithelial-mesenchymal transition and by enriching a cancer stem cell phenotype in tumor epithelial cells. In addition to these epithelial alterations, we also observed marked inflammation in tumor stroma. AKT is a central signaling mediator of the PI3K pathway. However, molecular analysis suggested that progression of PIK3CA-driven HNSCC is facilitated by PDK1 and enhanced TGFβ signaling rather than by AKT. Examination of human HNSCC clinical samples revealed that both PIK3CA and PDK1 protein levels correlated with tumor progression, highlighting the significance of this pathway. In summary, our results offer significant insight into how PIK3CA-overexpression drives HNSCC invasion and metastasis, providing a rationale for targeting PI3K/PDK1 and TGFβ signaling in advanced HNSCC patients with PIK3CA amplification.

Protein tyrosine phosphatase receptor S acts as a metastatic suppressor in hepatocellular carcinoma by control of epithermal growth factor receptor-induced epithelial-mesenchymal transition

Hepatocellular carcinoma (HCC) is the third-most lethal cancer worldwide. Understanding the molecular pathogenesis of HCC recurrence and metastasis is the key to improve patients' prognosis. In this study, we report that protein tyrosine phosphatase receptor S (PTPRS) is significantly down-regulated in nearly 80% of HCCs, and its expression negatively correlates with aggressive pathological features, such as larger tumor size and advanced stage. In addition, PTPRS deficiency is independently associated with shorter survival and increased recurrence in patients, although 16.7% of HCCs show intratumor heterogeneous expression of PTPRS. Restoration of wild-type, but not mutant, PTPRS expression significantly inhibits HCC cell migration and invasion in vitro as well as lung metastasis in vivo, whereas knockdown of its expression significantly promotes invasion and metastasis. Notably, PTPRS-regulated HCC invasiveness is accompanied by typical changes of epithelial-mesenchymal transition (EMT). Moreover, PTPRS forms a complex with epithermal growth factor receptor (EGFR) and regulates its tyrosine residues' phosphorylation. Ectopic expression of EGFR reverses the metastasis-inhibiting effects of PTPRS, whereas silencing of EGFR or inhibiting phosphorylation of key molecules in EGFR downstream pathways reinhibits EMT and metastasis caused by PTPRS down-regulation. Meanwhile, promoter hypermethylation of PTPRS is frequently detected in HCC samples and cell lines. Treatment with a demethylation agent, 5-aza-2'-deoxycytidine, recovers PTPRS expression in a dose-dependent manner.

CONCLUSIONS

Epigenetic inactivation of PTPRS may increase phosphorylation and activity of EGFR signaling to promote EMT and metastasis in HCC.

The Cancer Genomics Resource List 2014

CONTEXT

Genomic sequencing for cancer is offered by commercial for-profit laboratories, independent laboratory networks, and laboratories in academic medical centers and integrated health networks. The variability among the tests has created a complex, confusing environment.

OBJECTIVE

To address the complexity, the Personalized Health Care (PHC) Committee of the College of American Pathologists proposed the development of a cancer genomics resource list (CGRL). The goal of this resource was to assist the laboratory pathology and clinical oncology communities.

DESIGN

The PHC Committee established a working group in 2012 to address this goal. The group consisted of site-specific experts in cancer genetic sequencing. The group identified current next-generation sequencing (NGS)-based cancer tests and compiled them into a usable resource. The genes were annotated by the working group. The annotation process drew on published knowledge, including public databases and the medical literature.

RESULTS

The compiled list includes NGS panels offered by 19 laboratories or vendors, accompanied by annotations. The list has 611 different genes for which NGS-based mutation testing is offered. Surprisingly, of these 611 genes, 0 genes were listed in every panel, 43 genes were listed in 4 panels, and 54 genes were listed in 3 panels. In addition, tests for 393 genes were offered by only 1 or 2 institutions. Table 1 provides an example of gene mutations offered for breast cancer genomic testing with the annotation as it appears in the CGRL 2014.

CONCLUSIONS

The final product, referred to as the Cancer Genomics Resource List 2014, is available as supplemental digital content.

A Monoclonal Antibody to ADAM17 Inhibits Tumor Growth by Inhibiting EGFR and Non-EGFR-Mediated Pathways

ADAM17 is the primary sheddase for HER pathway ligands. We report the discovery of a potent and specific ADAM17 inhibitory antibody, MEDI3622, which induces tumor regression or stasis in many EGFR-dependent tumor models. The inhibitory activity of MEDI3622 correlated with EGFR activity both in a series of tumor models across several indications as well in as a focused set of head and neck patient-derived xenograft models. The antitumor activity of MEDI3622 was superior to that of EGFR/HER pathway inhibitors in the OE21 esophageal model and the COLO205 colorectal model suggesting additional activity outside of the EGFR pathway. Combination of MEDI3622 and cetuximab in the OE21 model was additive and eradicated tumors. Proteomics analysis revealed novel ADAM17 substrates that function outside of the HER pathways and may contribute toward the antitumor activity of the monoclonal antibody.

Tumor vessel up-regulation of INSR revealed by single-cell expression analysis of the tyrosine kinome and phosphatome in human cancers

The tyrosine kinome and phosphatome harbor oncogenes and tumor suppressor genes and important regulators of angiogenesis and tumor stroma formation. To provide a better understanding of their potential roles in cancer, we analyzed the expression of 85 tyrosine kinases and 42 tyrosine phosphatases by in situ hybridization 48 human normal and 24 tumor tissue specimens. Nine-tenths of the assessed transcripts had tumor cell expression concordant with expression array databases. Further, pan-cancer expression of AATK, PTPRK, and PTPRU and expression of PTPRS in a subset of tumors were observed. To demonstrate tumor subcompartment resolution, we validated the predicted tumor stroma-specific markers HTRA1, HTRA3, MXRA5, MXRA8, and SERPING1 in situ. In addition to known vascular and stromal markers such as PDGFRB, we observed stromal expression of PTK6 and TNS1 and vascular expression of INSR, PTPRF, PTPRG, PTPRU, and TNS1, of which INSR emerged as a tumor-specific vessel marker. This study demonstrates the feasibility of large-scale analyses to chart the transcriptome in situ in human cancers and their ability to identify novel cancer biomarkers.

Nab-paclitaxel-based compared to docetaxel-based induction chemotherapy regimens for locally advanced squamous cell carcinoma of the head and neck

We previously reported that nab-paclitaxel-based induction chemotherapy (IC) and concurrent chemoradiotherapy resulted in low relapse rates (13%) and excellent survival in head and neck squamous cell carcinoma (HNSCC). We compare the disease-specific survival (DSS) and overall survival (OS) between patients given nab-paclitaxel, cisplatin, and fluorouracil with cetuximab (APF-C) and historical controls given docetaxel, cisplatin, and fluorouracil with cetuximab (TPF-C). Patients with locally advanced HNSCC were treated with APF-C (n = 30) or TPF-C (n = 38). After 3 cycles of IC, patients were scheduled to receive cisplatin concurrent with definitive radiotherapy. T and N classification and smoking history were similar between the two groups and within p16-positive and p16-negative subsets. The median duration of follow-up for living patients in the APF-C group was 43.5 (range: 30-58) months versus 52 (range: 13-84) months for TPF-C. The 2-year DSS for patients treated with APF-C was 96.7% [95% Confidence Interval (CI): 85.2%, 99.8%] and with TPF-C was 77.6% (CI: 62.6%, 89.7%) (P = 0.0004). Disease progression that resulted in death was more frequent in the TPF-C group (39%) compared with the APF-C group (3%) when adjusted for competing risks of death from other causes (Gray's test, P = 0.0004). In p16 positive OPSCC, the 2-year DSS for APF-C was 100% and for TPF-C was 74.6% (CI: 47.4%, 94.6%) (P = 0.0019) and the 2-year OS for APF-C was 94.1% (CI: 65.0%, 99.2%) and for TPF-C was 74.6% (CI: 39.8%, 91.1%) (P = 0.013). In p16 negative HNSCC, the 2-year DSS for APF-C was 91.7% (CI: 67.6%, 99.6%) and for TPF-C was 82.6% (CI: 64.4%, 94.8%) (P = 0.092). A 2-year DSS and OS were significantly better with a nab-paclitaxel-based IC regimen (APF-C) compared to a docetaxel-based IC regimen (TPF-C) in p16-positive OPSCC.

A randomized, phase 2 trial of docetaxel with or without PX-866, an irreversible oral phosphatidylinositol 3-kinase inhibitor, in patients with relapsed or metastatic head and neck squamous cell cancer

INTRODUCTION

The phosphotidylinositol-3 kinase (PI3K)/serine-threonine kinase (AKT)/mammalian target of rapamycin (mTOR) signaling pathway is frequently altered in head and neck squamous cell cancer (HNSCC). PX-866 is an oral, irreversible, pan-isoform inhibitor of PI3K. Preclinical models revealed synergy with docetaxel and a phase 1 trial demonstrated tolerability of this combination. This randomized phase 2 study evaluated PX-866 combined with docetaxel in patients with advanced, refractory HNSCC.

METHODS

Patients with locally advanced, recurrent or metastatic HNSCC who had received at least one and no more than two prior systemic treatment regimens were randomized (1:1) to a combination of docetaxel (75mg/m(2) IV every 21days) with or without PX-866 (8mg PO daily; Arms A and B, respectively). The primary endpoint was progression free survival (PFS). Secondary endpoints included objective response rate (RR), overall survival (OS), toxicity, and correlation of biomarker analyses with efficacy outcomes.

RESULTS

85 patients were enrolled. There was a non-significant improvement in response rate in the combination arm (14% vs. 5%; P=0.13). Median PFS was 92days in Arm A and 82days in Arm B (P=0.42). There was no difference in OS between the two arms (263 vs. 195days; P=0.62). Grade 3 or higher adverse events were infrequent, but more common in the combination arm with respect to diarrhea (17% vs. 2%), nausea (7% vs. 0%), and febrile neutropenia (21% vs. 5%); grade 3 or higher anemia was more frequent in arm B (7% vs. 27%). PIK3CA mutations or PTEN loss were infrequently observed.

CONCLUSION

The addition of PX-866 to docetaxel did not improve PFS, RR, or OS in patients with advanced, refractory HNSCC without molecular pre-selection.

Mechanisms of and therapeutic approaches for overcoming resistance to epidermal growth factor receptor (EGFR)-targeted therapy in squamous cell carcinoma of the head and neck (SCCHN)

The majority of squamous cell carcinoma of the head and neck (SCCHN) overexpress epidermal growth factor receptor (EGFR), which has been associated with poor treatment response and survival. However, only modest success has been achieved with the use of single agents that target EGFR, possibly due to primary and acquired resistance. This review will discuss key mechanisms of and therapeutic approaches to overcoming resistance to EGFR-targeted therapy in SCCHN. Recent preclinical and clinical investigations have demonstrated that other ErbB family receptors (eg, HER2 and HER3) and other horizontal resistance mechanisms, as well as activation of downstream signaling pathways, epigenetic events, and nuclear EGFR, are possible mediators of resistance to anti-EGFR therapeutics. Key downstream pathways that may be implicated in EGFR resistance include phosphatidylinositol-3-kinase/protein kinase B, vascular endothelial growth factor (VEGF), and mammalian target of rapamycin (mTOR). Multiple agents that target EGFR and other ErbB family members (ie, lapatinib, afatinib, and dacomitinib), as well as combination therapies that target EGFR and selected other pathways (eg, VEGF, mTOR, and c-Met) are being investigated clinically. In addition, several phase II and III trials continue to investigate strategies to enhance the efficacy of EGFR-targeted therapy in SCCHN.

Novel treatments for head and neck squamous cell carcinoma: preclinical identification and clinical investigation

Head and neck squamous cell carcinoma (HNSCC) is a common cancer worldwide. Classically, it is a disease related to tobacco and alcohol use; an increasing number of patients are being diagnosed with HNSCC caused by infection with the human papillomavirus. New deep-sequencing techniques have confirmed the importance of p53 and EGF receptor in HNSCC development, and have identified pathways of critical importance, such as PI3K/mTOR and NOTCH. Increasing knowledge of key molecular features has lead to new therapeutic avenues for HNSCC. Novel therapies under investigation in HNSCC include antibody and small molecule inhibitors of EGF receptor and its family members, PI3K inhibitors, antiangiogenic agents, immunotherapies and agents interacting with early developmental pathways such as Hedgehog.

Liver cancer oncogenomics: opportunities and dilemmas for clinical applications

Primary liver cancers are among the most rapidly evolving malignant tumors worldwide. An underlying chronic inflammatory liver disease, which precedes liver cancer development for several decades and frequently creates a pro-oncogenic microenvironment, impairs progress in therapeutic approaches. Molecular heterogeneity of liver cancer is potentiated by a crosstalk between epithelial tumor and stromal cells that complicate translational efforts to unravel molecular mechanisms of hepatocarcinogenesis with a drugable intend. Next-generation sequencing has greatly advanced our understanding of cancer development. With regards to liver cancer, the unprecedented coverage of next-generation sequencing has created a detailed map of genetic alterations and identified key somatic changes such as CTNNB1 and TP53 as well as several previously unrecognized recurrent disease-causing alterations that could contribute to new therapeutic approaches. Importantly, these investigations indicate that a classical oncogene addiction cannot be assumed for primary liver cancer. Therefore, hepatocarcinogenesis can be considered a paradigm suitable for individualized medicine.

A randomized, phase II trial of cetuximab with or without PX-866, an irreversible oral phosphatidylinositol 3-kinase inhibitor, in patients with relapsed or metastatic head and neck squamous cell cancer

BACKGROUND

The phosphotidylinositol-3 kinase (PI3K)/serine-threonine kinase/mammalian target of rapamycin signaling pathway is frequently altered in head and neck squamous cell cancer (HNSCC). PX-866 is an oral, irreversible, pan-isoform inhibitor of PI3K. A phase I trial demonstrated tolerability of this combination. This randomized phase II study evaluated PX-866 combined with cetuximab in patients with advanced, refractory HNSCC.

METHODS

Patients with recurrent or metastatic HNSCC who had received at least one and no more than two prior systemic treatment regimens were randomized (1 : 1) to cetuximab with or without PX-866 (8 mg p.o. daily; arms A and B, respectively). The primary end point was progression-free survival (PFS). Secondary end points included objective response rate (ORR), overall survival (OS), toxicity, and correlation of key biomarkers with efficacy outcomes.

RESULTS

Eighty-three patients were enrolled. There was a similar response rate between arms (10% versus 7%). Of patients for whom tissue was assessable, 57% were human papillomavirus (HPV) positive. Median PFS was 80 days in both arms and there was no difference in OS between the two arms (211 versus 256 days). Overall toxicity was higher in arm A compared with arm B, especially in terms of nausea (53% versus 23%), vomiting (45% versus 15%), fatigue (43% versus 23%), diarrhea (40% versus 21%), and hypokalemia (25% versus 10%). Grade 3 or higher adverse events were infrequent, but more common in the combination arm although without a specific pattern. PIK3CA mutations were observed in 17% of the cases assessed, and PTEN loss was infrequently observed.

CONCLUSION

The addition of PX-866 to cetuximab did not improve PFS, RR, or OS in patients with advanced, refractory HNSCC enrolled without molecular preselection. In this contemporary cohort, HPV-positive patients comprised the majority, and neither HPV-positive nor HPV-negative patients derived clinical benefit for the addition of cetuximab plus PX-866.