The PI3K/Akt/mTOR axis in head and neck cancer: functions, aberrations, cross-talk, and therapies

Urolithin A, induces apoptosis and autophagy crosstalk in Oral Squamous Cell Carcinoma via mTOR /AKT/ERK1/2 pathway

BACKGROUND

Oral squamous cell carcinoma (OSCC) is the most prevalent malignancy in the world with an alarming rate of mortality. Despite the advancement in treatment strategies and drug developments, the overall survival rate remains poor. Therefore, it is imperative to develop alternative or complimentary anti cancer drugs with minimum off target effects. Urolithin A, a microbial metabolite of ellagic acid and ellagitannins produced endogenously by human gut micro biome is considered to have anti-cancerous activity. However anti tumorigenic effect of urolithin A in OSCC is yet to be elucidated. In this study, we examined whether urolithin A inhibits cell growth and induces both apoptosis and autophagy dependent cell death in OSCC cell lines.

PURPOSE

The present study aims to evaluate the potential of urolithin A to inhibit OSCC and its regulatory effect on OSCC proliferation and invasion in vitro and in vivo mouse models.

METHODS

We evaluated whether urolithin A could induce cell death in OSCC in vitro and in vivo mouse models.

RESULTS

Flow cytometric and immunoblot analysis on Urolithin A treated OSCC cell lines revealed that urolithin A markedly induced cell death of OSCC via the induction of endoplasmic reticulum stress and subsequent inhibition of AKT and mTOR signaling as evidenced by decreased levels of phosphorylated mTOR and 4EBP1. This further revealed a possible cross talk between apoptotic and autophagic signaling pathways. In vivo study demonstrated that urolithin A treatment reduced tumor size and showed a decrease in mTOR, ERK1/2 and Akt levels along with a decrease in proliferation marker, Ki67. Taken together, in vitro as well as our in vivo data indicates that urolithin A is a potential anticancer agent and the inhibition of AKT/mTOR/ERK signalling is crucial in Urolithin A induced growth suppression in oral cancer.

CONCLUSION

Urolithin A exerts its anti tumorigenic activity through the induction of apoptotic and autophagy pathways in OSCC. Our findings suggest that urolithin A markedly induced cell death of oral squamous cell carcinoma via the induction of endoplasmic reticulum stress and subsequent inhibition of AKT and mTOR signaling as evidenced by decreased levels of phosphorylated mTOR and 4EBP1. Urolithin A remarkably suppressed tumor growth in both in vitro and in vivo mouse models signifying its potential as an anticancer agent in the prevention and treatment of OSCC. Henceforth, our findings provide a new insight into the therapeutic potential of urolithin A in the prevention and treatment of OSCC.

Deciphering the complex landscape of post-translational modifications on PKM2: Implications in head and neck cancer pathogenesis

In the vast landscape of human health, head and neck cancer (HNC) poses a significant health burden globally, necessitating the exploration of novel diagnostics and therapeutics. Metabolic alterations occurring within tumor microenvironment are crucial to understand the foundational cause of HNC. Post-translational modifications (PTMs) have recently emerged as a silent foe exerting a significantly heightened influence on various aspects of the biological processes associated with the onset and advancement of cancer, particularly in the context of HNC. There are numerous targets involved in HNC but recently, the enzyme pyruvate kinase M2 (PKM2) has come out as a hot target due to its involvement in glycolysis resulting in metabolic reprogramming of cancer cells. Various PTMs have been reported to affect the structure and function of PKM2 by modulating its activity. This review aims to investigate the impact of PTMs on the interaction between PKM2 and several signaling pathways and transcription factors in the context of HNC. These interactions possess significant ramification for cellular proliferation, apoptosis, angiogenesis and metastasis. This review primarily explores the role of PTMs influencing PKM2 and its involvement in tumor development. While acknowledging the significance of PKM2 interactions with other tumor regulators, the emphasis lies on dissecting PTM-related mechanisms rather than solely scrutinizing individual regulators. It lays the framework for the development of more sophisticated diagnostic tools and uncovers exciting possibilities for precision medicine essential for effectively addressing the complexity of this malignancy in a precise and focused manner.

Unveiling the Mechanisms Underlying the Immunotherapeutic Potential of Gene-miRNA and Drugs in Head and Neck Cancer

Head and neck cancer ranks as the sixth-most common malignancy worldwide, characterized by high mortality and recurrence rates. Research studies indicate that molecular diagnostics play a crucial role in the early detection and prognostic evaluation of these diseases. This study aimed to identify potential biomarkers for head and neck cancer and elucidate their interactions with miRNAs and possible therapeutic drugs. Four drivers, namely, FN1, IL1A, COL1A1, and MMP9, were identified using network biology and machine learning approaches. Gene set variation analysis (GSVA) showed that these genes were significantly involved in different biological processes and pathways, including coagulation, UV-response-down, apoptosis, NOTCH signaling, Wnt-beta catenin, and other signal pathways. The diagnostic value of these hub genes was validated using receiver operating characteristic (ROC) curves. The top interactive miRNAs, including miR-128-3p, miR-218-5p, miR-214-3p, miR-124-3p, miR-129-2-3p, and miR-1-3p, targeted the key genes. Furthermore, the interaction between the key genes and drugs was also identified. In summary, the key genes and miRNAs or drugs reported in this study might provide valuable information for potential biomarkers to increase the prognosis and diagnosis of head and neck cancer.

Network pharmacology: an efficient but underutilized approach in oral, head and neck cancer therapy-a review

The application of network pharmacology (NP) has advanced our understanding of the complex molecular mechanisms underlying diseases, including neck, head, and oral cancers, as well as thyroid carcinoma. This review aimed to explore the therapeutic potential of natural network pharmacology using compounds and traditional Chinese medicines for combating these malignancies. NP serves as a pivotal tool that provides a comprehensive view of the interactions among compounds, genes, and diseases, thereby contributing to the advancement of disease treatment and management. In parallel, this review discusses the significance of publicly accessible databases in the identification of oral, head, and neck cancer-specific genes. These databases, including those for head and neck oral cancer, head and neck cancer, oral cancer, and genomic variants of oral cancer, offer valuable insights into the genes, miRNAs, drugs, and genetic variations associated with these cancers. They serve as indispensable resources for researchers, clinicians, and drug developers, contributing to the pursuit of precision medicine and improved treatment of these challenging malignancies. In summary, advancements in NP could improve the globalization and modernization of traditional medicines and prognostic targets as well as aid in the development of innovative drugs. Furthermore, this review will be an eye-opener for researchers working on drug development from traditional medicines by applying NP approaches.

Novel non-invasive molecular signatures for oral cavity cancer, by whole transcriptome and small non-coding RNA sequencing analyses: Predicted association with PI3K/AKT/mTOR pathway

INTRODUCTION

Identification of molecular biomarkers in the saliva and serum of oral cavity cancer patients represents a first step in the development of essential and efficient clinical tools for early detection and post-treatment monitoring. We hypothesized that molecular analyses of paired saliva and serum samples from an individual would likely yield better results than analyses of either serum or saliva alone.

MATERIALS AND METHODS

We performed whole-transcriptome and small non-coding RNA sequencing analyses on 32 samples of saliva and serum collected from the same patients with oral squamous cell carcinoma (OSCC) and healthy controls (HC).

RESULTS

We identified 12 novel saliva and serum miRNAs and a panel of unique miRNA and mRNA signatures, significantly differentially expressed in OSCC patients relative to HC (log2 fold change: 2.6-26.8; DE: 0.02-0.000001). We utilized a combined panel of the 10 top-deregulated miRNAs and mRNAs and evaluated their putative diagnostic potential (>87% sensitivity; 100% specificity), recommending seven of them for further validation. We also identified unique saliva and serum miRNAs associated with OSCC and smoking history (OSCC smokers vs. never-smokers or HC: log2 fold change: 22-23; DE: 0.00003-0.000000001). Functional and pathway analyses indicated interactions between the discovered OSCC-related non-invasive miRNAs and mRNAs and their targets, through PI3K/AKT/mTOR signaling.

CONCLUSION

Our data support our hypothesis that using paired saliva and serum from the same individuals and deep sequencing analyses can provide unique combined mRNA and miRNA signatures associated with canonical pathways that may have a diagnostic advantage relative to saliva or serum alone and may be useful for clinical testing. We believe this data will contribute to effective preventive care by post-treatment monitoring of patients, as well as suggesting potential targets for therapeutic approaches.

A first-in-human phase I study of TAS-117, an allosteric AKT inhibitor, in patients with advanced solid tumors

PURPOSE

TAS-117 is a highly potent and selective, oral, allosteric pan-AKT inhibitor under development for advanced/metastatic solid tumors. The safety, clinical pharmacology, pharmacogenomics and efficacy were investigated.

METHODS

This phase I, open-label, non-randomized, dose-escalating, first-in-human study enrolled patients with advanced/metastatic solid tumors and comprised three phases (dose escalation phase [DEP], regimen modification phase [RMP], and safety assessment phase [SAP]). The SAP dose and regimen were determined in the DEP and RMP. Once-daily and intermittent dosing (4 days on/3 days off, 21-day cycles) were investigated. The primary endpoints were dose-limiting toxicities (DLTs) in Cycle 1 of the DEP and RMP and incidences of adverse events (AEs) and adverse drug reactions (ADRs) in the SAP. Secondary endpoints included pharmacokinetics, pharmacodynamics, pharmacogenomics, and antitumor activity.

RESULTS

Of 66 enrolled patients, 65 received TAS-117 (DEP, n = 12; RMP, n = 10; SAP, n = 43). No DLTs were reported with 24-mg/day intermittent dosing, which was selected as a recommended dose in SAP. In the SAP, 98.5% of patients experienced both AEs and ADRs (grade ≥ 3, 67.7% and 60.0%, respectively). In the dose range tested (8 to 32 mg/day), TAS-117 pharmacokinetics were dose proportional, and pharmacodynamic analysis showed a reduction of phosphorylated PRAS40, a direct substrate of AKT. Four patients in the SAP had confirmed partial response.

CONCLUSION

Oral doses of TAS-117 once daily up to 16 mg/day and intermittent dosing of 24 mg/day were well tolerated. TAS-117 pharmacokinetics were dose proportional at the doses evaluated. Antitumor activity may occur through AKT inhibition.

TRIAL REGISTRATION

jRCT2080222728 (January 29, 2015).

Insights into metastatic roadmap of head and neck cancer squamous cell carcinoma based on clinical, histopathological and molecular profiles

The incidence of head and neck cancer (HNC), constituting approximately one in ten cancer cases worldwide, affects approximately 644,000 individuals annually. Managing this complex disease involves various treatment modalities such as systemic therapy, radiation, and surgery, particularly for patients with locally advanced disease. HNC treatment necessitates a multidisciplinary approach due to alterations in patients' genomes affecting their functionality. Predominantly, squamous cell carcinomas (SCCs), the majority of HNCs, arise from the upper aerodigestive tract epithelium. The epidemiology, staging, diagnosis, and management techniques of head and neck squamous cell carcinoma (HNSCC), encompassing clinical, image-based, histopathological and molecular profiling, have been extensively reviewed. Lymph node metastasis (LNM) is a well-known predictive factor for HNSCC that initiates metastasis and significantly impacts HNSCC prognosis. Distant metastasis (DM) in HNSCC has been correlated to aberrant expression of cancer cell-derived cytokines and growth factors triggering abnormal activation of several signaling pathways that boost cancer cell aggressiveness. Recent advances in genetic profiling, understanding tumor microenvironment, oligometastatic disease, and immunotherapy have revolutionized treatment strategies and disease control. Future research may leverage genomics and proteomics to identify biomarkers aiding individualized HNSCC treatment. Understanding the molecular basis, genetic landscape, atypical signaling pathways, and tumor microenvironment have enhanced the comprehension of HNSCC molecular etiology. This critical review sheds light on regional and distant metastases in HNSCC, presenting major clinical and laboratory features, predictive biomarkers, and available therapeutic approaches.

NSD1 supports cell growth and regulates autophagy in HPV-negative head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide. Despite advances in therapeutic management and immunotherapy, the 5-year survival rate for head and neck cancer remains at ~66% of all diagnosed cases. A better definition of drivers of HPV-negative HNSCC that are targetable points of tumor vulnerability could lead to significant clinical advances. NSD1 is a histone methyltransferase that catalyzes histone H3 lysine 36 di-methylation (H3K36me2); mutations inactivating NSD1 have been linked to improved outcomes in HNSCC. In this study, we show that NSD1 induces H3K36me2 levels in HNSCC and that the depletion of NSD1 reduces HNSCC of cell growth in vitro and in vivo. We also find that NSD1 strongly promotes activation of the Akt/mTORC1 signaling pathway. NSD1 depletion in HNSCC induces an autophagic gene program activation, causes accumulation of the p62 and LC3B-II proteins, and decreases the autophagic signaling protein ULK1 at both protein and mRNA levels. Reflecting these signaling defects, the knockdown of NSD1 disrupts autophagic flux in HNSCC cells. Taken together, these data identify positive regulation of Akt/mTORC1 signaling and autophagy as novel NSD1 functions in HNSCC, suggesting that NSD1 may be of value as a therapeutic target in this cancer.

Targeting PI3K/AKT/mTOR and MAPK Signaling Pathways in Gastric Cancer

Gastric cancer (GC) is the fourth leading cause of death worldwide, with more than 1 million cases diagnosed every year. Helicobacter pylori represents the main risk factor, being responsible for 78% of the cases. Increased amounts of salt, pickled food, red meat, alcohol, smoked food, and refined sugars negatively affect the stomach wall, contributing to GC development. Several gene mutations, including PIK3CA, TP53, ARID1A, CDH1, Ras, Raf, and ERBB3 are encountered in GC pathogenesis, leading to phosphatidylinositol 3-kinase (PI3K) protein kinase B (AKT)/mammalian target of rapamycin (mTOR)-PI3K/AKT/mTOR-and mitogen-activated protein kinase (MAPK) signaling pathway activation and promoting tumoral activity. Helicobacter pylori, growth factors, cytokines, hormones, and oxidative stress also activate both pathways, enhancing GC development. In clinical trials, promising results have come from monoclonal antibodies such as trastuzumab and ramucirumab. Dual inhibitors targeting the PI3K/AKT/mTOR and MAPK signaling pathways were used in vitro studies, also with promising results. The main aim of this review is to present GC incidence and risk factors and the dysregulations of the two protein kinase complexes together with their specific inhibitors.

Role of Cannabinoids in Oral Cancer

Cannabinoids have incited scientific interest in different conditions, including malignancy, due to increased exposure to cannabis. Furthermore, cannabinoids are increasingly used to alleviate cancer-related symptoms. This review paper aims to clarify the recent findings on the relationship between cannabinoids and oral cancer, focusing on the molecular mechanisms that could link cannabinoids with oral cancer pathogenesis. In addition, we provide an overview of the current and future perspectives on the management of oral cancer patients using cannabinoid compounds. Epidemiological data on cannabis use and oral cancer development are conflicting. However, in vitro studies assessing the effects of cannabinoids on oral cancer cells have unveiled promising anti-cancer features, including apoptosis and inhibition of cell proliferation. Downregulation of various signaling pathways with anti-cancer effects has been identified in experimental models of oral cancer cells exposed to cannabinoids. Furthermore, in some countries, several synthetic or phytocannabinoids have been approved as medical adjuvants for the management of cancer patients undergoing chemoradiotherapy. Cannabinoids may improve overall well-being by relieving anxiety, depression, pain, and nausea. In conclusion, the link between cannabinoid compounds and oral cancer is complex, and further research is necessary to elucidate the potential risks or their protective impact on oral cancer.

Targeting cellular metabolism in head and neck cancer precision medicine era: A promising strategy to overcome therapy resistance

Head and neck squamous cell carcinoma (HNSCC) is among the most prevalent cancer worldwide, with the most severe impact on quality of life of patients. Despite the development of multimodal therapeutic approaches, the clinical outcomes of HNSCC are still unsatisfactory, mainly caused by relatively low responsiveness to treatment and severe drug resistance. Metabolic reprogramming is currently considered to play a pivotal role in anticancer therapeutic resistance. This review aimed to define the specific metabolic programs and adaptations in HNSCC therapy resistance. An extensive literature review of HNSCC was conducted via the PubMed including metabolic reprogramming, chemo- or immune-therapy resistance. Glucose metabolism, fatty acid metabolism, and amino acid metabolism are closely related to the malignant biological characteristics of cancer, anti-tumor drug resistance, and adverse clinical results. For HNSCC, pyruvate, lactate and almost all lipid categories are related to the occurrence and maintenance of drug resistance, and targeting amino acid metabolism can prevent tumor development and enhance the response of drug-resistant tumors to anticancer therapy. This review will provide a better understanding of the altered metabolism in therapy resistance of HNSCC and promote the development of new therapeutic strategies against HNSCC, thereby contribute to a more efficacious precision medicine.

To Tip or Not to Tip: A New Combination for Precision Medicine in Head and Neck Cancer

Meaningful advances in targeted therapy for head and neck squamous cell carcinoma (HNSCC) have been hampered by limited availability of robust preclinical models for translational research. Using an impressive array of in vitro and in vivo preclinical HNSCC models, Smith and colleagues demonstrated the efficacy of alpelisib and tipifarnib combination therapy through sustained mTOR inhibition in PIK3CA/HRAS-dysregulated HNSCC, including preliminary evidence of robust antitumor activity in a patient enrolled in a precision medicine trial. This study in this issue of Cancer Research illustrates the value of preclinical avatars for informing biomarker-driven clinical trials to advance precision medicine in HNSCC and other cancers. See related article by Smith et al., p. 3252.

NSD1 supports cell growth and regulates autophagy in HPV-negative head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide. Despite advances in therapeutic management and immunotherapy, the five-year survival rate for head and neck cancer remains at ~66% of all diagnosed cases. A better definition of drivers of HPV-negative HNSCC that are targetable points of tumor vulnerability could lead to significant clinical advances. NSD1 is a histone methyltransferase which catalyzes histone H3 lysine 36 di-methylation (H3K36me2); mutations inactivating NSD1 have been linked to improved outcomes in HNSCC. In this study, we show that NSD1 induces H3K36me2 levels in HNSCC, and that the depletion of NSD1 reduces HNSCC of cell growth in vitro and in vivo. We also find that NSD1 strongly promotes activation of the Akt/mTORC1 signaling pathway. NSD1 depletion in HNSCC induces an autophagic gene program activation, causes accumulation of the p62 and LC3B-II proteins, and decreases the autophagic signaling protein ULK1 at both protein and mRNA levels. Reflecting these signaling defects, knockdown of NSD1 disrupts autophagic flux in HNSCC cells. Taken together, these data identify positive regulation of Akt/mTORC1 signaling and autophagy as novel NSD1 functions in HNSCC, suggesting that NSD1 may be of value as a therapeutic target in this cancer.

Role of tissue markers associated with tumor microenvironment in the progression and immune suppression of oral squamous cell carcinoma

Head and neck cancers (HNC) continues to dominate major cancers contributing to  mortality worldwide. Squamous cell carcinoma is the major type of HNC. Oral Squamous Cell Carcinoma grouped under HNC is a malignant tumor occurring in the oral cavity. The primary risk factors of OSCC are tobacco, alcohol consumption, etc. This review focuses on modulations, mechanisms, growth and differentiation of oral squamous cell carcinoma. Cancer cell surrounds itself with a group of elements forming a favorable environment known as tumor microenvironment (TME). It consists of numerous cells which includes immune cells, blood cells and acellular components that are responsible for the progression, immunosuppression, metastasis and angiogenesis of cancer. This review highlights the most important tissue biomarkers (mTOR, CAF, FOXp3, CD163, CD33, CD34) that are associated with TME cells. mTOR remains as the primary regulator responsible in cancer and its importance towards immune-suppression is highlighted. Tumor-associated macrophages associated with cancer development and its relationship with immunomodulatory mechanism and Tregs, which are potential blockers of immune response and its mechanism and aberrations are discussed. Cancer-associated fibroblasts that are a part of TME and their role in evading the immune response and myeloid derived suppressor cells that have slight control over the immune response and their mechanism in the tumor progression is further explained. These markers have been emphasised as therapeutic targets and are currently in different stages of clinical trials.

PI3K/Akt signalling pathway-associated long noncoding RNA signature predicts the prognosis of laryngeal cancer patients

The PI3K/Akt signalling pathway is associated with the occurrence and development of tumours and significantly affects the prognosis of patients. We established a predictive signature based on the PI3K/Akt pathway to predict the prognosis of patients. The RNA-seq and clinical data of laryngeal cancer patients were downloaded from The Cancer Genome Atlas (TCGA) database. Three lncRNAs (MNX1-AS1, LINC00330, LSAMP-AS1) were selected through univariate, multivariate Cox and log-rank test analysis to establish a prognostic signature. The patients were then divided into high-risk and low-risk groups based on their risk score. In the TCGA training set, the survival time of the high-risk group was shorter than that of the low-risk group (P < 0.01). Follicular helper T cells were lower in the high-risk group (P = 0.022), and CCR, inflammation promotion, parainflammation, and type I IFN immune function were suppressed. The results of the drug sensitivity analysis suggest that the high-risk group is sensitive to AKT inhibitors. The establishment of the signature was also verified based on the clinical data. Three lncRNAs can facilitate the migration, invasion, and vitality of cancer cells in vitro, and vice versa. Moreover, p-AKT (Ser473) and p-PI3K were highly activated in the cells overexpressing the abovementioned three lncRNAs. The PI3K/Akt signalling pathway-associated prognosis signature has a good predictive effect.

The effect of matrices on the gene expression profile of patient-derived head and neck carcinoma cells for in vitro therapy testing

OBJECTIVE

Head and neck squamous cell carcinoma (HNSCC) is a highly aggressive tumor with a 5-year mortality rate of ~ 50%. New in vitro methods are needed for testing patients' cancer cell response to anti-cancer treatments. We aimed to investigate how the gene expression of fresh carcinoma tissue samples and freshly digested single cancer cells change after short-term cell culturing on plastic, Matrigel or Myogel. Additionally, we studied the effect of these changes on the cancer cells' response to anti-cancer treatments.

MATERIALS/METHODS

Fresh tissue samples from HNSCC patients were obtained perioperatively and single cells were enzymatically isolated and cultured on either plastic, Matrigel or Myogel. We treated the cultured cells with cisplatin, cetuximab, and irradiation; and performed cell viability measurement. RNA was isolated from fresh tissue samples, freshly isolated single cells and cultured cells, and RNA sequencing transcriptome profiling and gene set enrichment analysis were performed.

RESULTS

Cancer cells obtained from fresh tissue samples changed their gene expression regardless of the culturing conditions, which may be due to the enzymatic digestion of the tissue. Myogel was more effective than Matrigel at supporting the upregulation of pathways related to cancer cell proliferation and invasion. The impacts of anti-cancer treatments varied between culturing conditions.

CONCLUSIONS

Our study showed the challenge of in vitro cancer drug testing using enzymatic cell digestion. The upregulation of many targeted pathways in the cultured cells may partially explain the common clinical failure of the targeted cancer drugs that pass the in vitro testing.

Xanol Promotes Apoptosis and Autophagy and Inhibits Necroptosis and Metastasis via the Inhibition of AKT Signaling in Human Oral Squamous Cell Carcinoma

Angelica keiskei Koidzumi (A. keiskei) is used as a traditional medicine, anti-aging agent, and health food, as well as to restore vitality. Xanthoangelol (xanol), a prenylated chalcone, is the predominant constituent of A. keiskei. Oral squamous cell carcinoma (OSCC), the most common malignancy, has a high proliferation rate and frequent metastasis. However, it is unknown whether xanol has anti-OSCC effects on apoptosis, autophagy, and necroptosis. In the present study, we purified xanol from A. keiskei and demonstrated that it suppressed cell proliferation and induced cytotoxicity in human OSCC. Xanol triggered apoptotic cell death by regulating apoptotic machinery molecules but inhibited necroptotic cell death by dephosphorylating the necroptotic machinery molecules RIP1, RIP3, and MLKL in human OSCC. We also found that xanol inhibited the PI3K/AKT/mTOR/p70S6K pathway and induced autophagosome formation by enhancing beclin-1 and LC3 expression levels and reducing p62 expression levels. Furthermore, we showed that xanol prevented the metastatic phenotypes of human OSCC by inhibiting migration and invasion via the reduction of MMP13 and VEGF. Finally, we demonstrated that xanol exerted anticancer effects on tumorigenicity associated with its transformed properties. Taken together, these findings demonstrate the anticancer effects and biological mechanism of action of xanol as an effective phytomedicine for human OSCC.

Head and neck cancer treatment in the era of molecular medicine

Head and neck cancers are a heterogeneous group of highly aggressive tumors and collectively represent the sixth most common cancer worldwide. Most head and neck cancers are squamous cell carcinomas (HNSCCs). Current multimodal treatment concepts combine surgery, chemotherapy, irradiation, immunotherapy, and targeted therapeutics. Recent scientific advancements have enabled a more precise molecular characterization of HNSCC and revealed novel therapeutic targets and prognostic/predictive biomarkers. Notably, HNSCC is characterized by complex relations between stromal, epithelial, and immune cells within the tumor microenvironment (TME). The TME consists of different subsets of immune cells that infiltrate the tumors and interact with the tumor cells or with each other. Understanding multiple pivotal factors in HNSCC tumorigenesis and tumor progression may help define novel targets and develop more effective therapies for patients. This review provides a comprehensive overview of the latest advances in the molecular biology of HNSCC and their effects on clinical oncology; it is meant for a broad readership in the head and neck cancers field.

Extract of Ficus septica modulates apoptosis and migration in human oral squamous cell carcinoma cells

According to the alarming statistical analysis of global cancer, there are over 19 million new diagnoses and more than 10 million deaths each year. One such cancer is the oral squamous cell carcinoma (OSCC), which requires new therapeutic strategies. Ficus septica extract has been used in traditional medicine to treat infectious diseases. In this study, we examined the anti-proliferative effects of an extract of F. septica bark (FSB) in OSCC cells. Our results showed that FSB caused a concentration-dependent reduction in the viability of SCC2095 OSCC cells, as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, and was less sensitive to fibroblasts. In addition, FSB induced apoptosis by activating caspases, accompanied by the modulation of Akt/mTOR/NF-κB and mitogen-activated protein kinase signaling. Moreover, FSB increased reactive oxygen species generation in a concentration-dependent manner in SCC2095 cells. Furthermore, FSB inhibited cell migration and modulated the levels of the cell adhesion molecules including E-cadherin, N-cadherin, and Snail in SCC2095 cells. Pinoresinol, a lignan isolated from FSB, showed antitumor effects in SCC2095 cells, implying that this compound might play an important role in FSB-induced OSCC cell death. Taken together, FSB is a potential anti-tumor agent against OSCC cells.

Machilin D Promotes Apoptosis and Autophagy, and Inhibits Necroptosis in Human Oral Squamous Cell Carcinoma Cells

Oral squamous cell carcinoma (OSCC) accounts for about 90% of all head and neck cancers, the prognosis is very poor, and there are no effective targeted therapies. Herein, we isolated Machilin D (Mach), a lignin, from the roots of Saururus chinensis (S. chinensis) and assessed its inhibitory effects on OSCC. Herein, Mach had significant cytotoxicity against human OSCC cells and showed inhibitory effects against cell adhesion, migration, and invasion by inhibiting adhesion molecules, including the FAK/Src pathway. Mach suppressed the PI3K/AKT/mTOR/p70S6K pathway and MAPKs, leading to apoptotic cell death. We investigated other modes of programmed cell death in these cells and found that Mach increased LC3I/II and Beclin1 and decreased p62, leading to autophagosomes, and suppressed the necroptosis-regulatory proteins RIP1 and MLKL. Our findings provide evidence that the inhibitory effects of Mach against human YD-10B OSCC cells are related to the promotion of apoptosis and autophagy and inhibition of necroptosis and are mediated via focal adhesion molecules.

Targeted therapy for head and neck cancer: signaling pathways and clinical studies

Head and neck cancer (HNC) is malignant, genetically complex and difficult to treat and is the sixth most frequent cancer, with tobacco, alcohol and human papillomavirus being major risk factors. Based on epigenetic data, HNC is remarkably heterogeneous, and treatment remains challenging. There is a lack of significant improvement in survival and quality of life in patients with HNC. Over half of HNC patients experience locoregional recurrence or distal metastasis despite the current multiple traditional therapeutic strategies and immunotherapy. In addition, resistance to chemotherapy, radiotherapy and some targeted therapies is common. Therefore, it is urgent to explore more effective and tolerable targeted therapies to improve the clinical outcomes of HNC patients. Recent targeted therapy studies have focused on identifying promising biomarkers and developing more effective targeted therapies. A well understanding of the pathogenesis of HNC contributes to learning more about its inner association, which provides novel insight into the development of small molecule inhibitors. In this review, we summarized the vital signaling pathways and discussed the current potential therapeutic targets against critical molecules in HNC, as well as presenting preclinical animal models and ongoing or completed clinical studies about targeted therapy, which may contribute to a more favorable prognosis of HNC. Targeted therapy in combination with other therapies and its limitations were also discussed.

Escape from Cellular Senescence Is Associated with Chromosomal Instability in Oral Pre-Malignancy

An escape from cellular senescence through the development of unlimited growth potential is one of the hallmarks of cancer, which is thought to be an early event in carcinogenesis. In this review, we propose that the molecular effectors of senescence, particularly the inactivation of TP53 and CDKN2A, together with telomere attrition and telomerase activation, all lead to aneuploidy in the keratinocytes from oral potentially malignant disorders (OPMD). Premalignant keratinocytes, therefore, not only become immortal but also develop genotypic and phenotypic cellular diversity. As a result of these changes, certain clonal cell populations likely gain the capacity to invade the underlying connective tissue. We review the clinical implications of these changes and highlight a new PCR-based assay to identify aneuploid cell in fluids such as saliva, a technique that is extremely sensitive and could facilitate the regular monitoring of OPMD without the need for surgical biopsies and may avoid potential biopsy sampling errors. We also draw attention to recent studies designed to eliminate aneuploid tumour cell populations that, potentially, is a new therapeutic approach to prevent malignant transformations in OPMD.

Current Insights and Progress in the Clinical Management of Head and Neck Cancer

Head and neck cancer (HNC), also known as the cancer that can affect the structures between the dura mater and the pleura, is the 6th most common type of cancer. This heterogeneous group of malignancies is usually treated with a combination of surgery and radio- and chemotherapy, depending on if the disease is localized or at an advanced stage. However, most HNC patients are diagnosed at an advanced stage, resulting in the death of half of these patients. Thus, the prognosis of advanced or recurrent/metastatic HNC, especially HNC squamous cell carcinoma (HNSCC), is notably poorer than the prognosis of patients diagnosed with localized HNC. This review explores the epidemiology and etiologic factors of HNC, the histopathology of this heterogeneous cancer, and the diagnosis methods and treatment approaches currently available. Moreover, special interest is given to the novel therapies used to treat HNC subtypes with worse prognosis, exploring immunotherapies and targeted/multi-targeted drugs undergoing clinical trials, as well as light-based therapies (i.e., photodynamic and photothermal therapies).

A Randomized Multi-institutional Phase II Trial of Everolimus as Adjuvant Therapy in Patients with Locally Advanced Squamous Cell Cancer of the Head and Neck

PURPOSE

Investigate whether adjuvant everolimus, an mTOR inhibitor, improves progression-free survival (PFS) in advanced-stage head and neck squamous cell carcinoma (HNSCC) and provide outcomes related to correlative biological factors associated with disease control.

PATIENTS AND METHODS

This was a prospective, randomized, double-blind phase II trial of patients with advanced-stage HNSCC from 13 institutions who were confirmed disease-free post-definitive therapy and enrolled between December 2010 and March 2015. Patients received adjuvant everolimus or placebo daily (10 mg, oral) for a maximum of 1 year. p16 IHC as a surrogate marker for human papillomavirus infection and whole-exome sequencing were performed. Cox proportional hazard models estimated hazard rates. Log-rank tests evaluated differences in survival. The primary endpoint was PFS. Secondary endpoints and objectives included overall survival (OS) and toxicity assessment.

RESULTS

52 patients [median (range) age, 58 (37-76) years; 43 men (83%), 9 women (17%)] were randomized to placebo (n = 24) or everolimus (n = 28). PFS favored everolimus, but was not significant [log-rank P = 0.093; HR = 0.44; 95% confidence interval (CI), 0.17-1.17]. There was no difference in OS (P = 0.29; HR = 0.57; 95% CI, 0.20-16.2). Everolimus resulted in significant improvement in PFS for p16-negative patients (n = 31; P = 0.031; HR = 0.26; 95% CI, 0.07-0.97), although subgroup analysis showed no difference for p16-positive patients (n = 21; P = 0.93). Further, PFS was significantly higher in TP53-mutated (TP53mut) patients treated with everolimus compared with placebo (log-rank P = 0.027; HR = 0.24; 95% CI, 0.06-0.95). No treatment difference was seen in patients with TP53 wild-type tumors (P = 0.79).

CONCLUSIONS

p16-negative and TP53mut patients may benefit from adjuvant treatment with everolimus.

Latifolin, a Natural Flavonoid, Isolated from the Heartwood of Dalbergia odorifera Induces Bioactivities through Apoptosis, Autophagy, and Necroptosis in Human Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is the most common malignant neoplasm with frequent metastasis and high mortality in the oral cavity. Plant-derived natural compounds are actively progressing as a trend for cancer treatment. Latifolin (Latif), is a natural flavonoid isolated from the heartwood of Dalbergia odorifera T. Chen (D. odorifera) has been known to have beneficial effects on anti-aging, anti-carcinogenic, anti-inflammatory, and cardio-protective activities. However, the anti-cancer effects of Latif are unknown in OSCC. Herein, as a result of analysis in terms of the aggressive features of OSCCs, we found that Latif significantly inhibited the cell proliferation of human YD-8 and YD-10B OSCCs, and caused the anti-metastatic activities by effectively blocking cell migration, invasion, and adhesion via the inactivation of focal adhesion kinase (FAK)/non-receptor tyrosine kinase (Src). Moreover, we found that Latif induced apoptotic cell death to suppress the cell survival and proliferation of YD-10B OSCCs by targeting PI3K/AKT/mTOR/p70S6K signaling. Finally, we analyzed in terms of autophagy and necroptosis, which are other mechanisms of programmed cell death and survival compared to apoptosis in YD-10B OSCCs. We found that Latif suppressed autophagic-related proteins and autophagosome formation, and also Latif inhibited necroptosis by dephosphorylating necroptosis-regulatory proteins (RIP1, RIP3, and MLKL). Given these findings, our results provided new evidence for Latif's biological effect and mechanism in YD-10B OSCCs, suggesting that Latif may be a new candidate for patients with OSCCs.

Activating mTOR Mutations Are Detrimental in Nutrient-Poor Conditions

The mTOR is a key regulator of cell growth that integrates growth factor signaling and nutrient availability and is a downstream effector of oncogenic receptor tyrosine kinases (RTK) and PI3K/Akt signaling. Thus, activating mTOR mutations would be expected to enhance growth in many tumor types. However, tumor sequencing data have shown that mTOR mutations are enriched only in renal clear cell carcinoma, a clinically hypervascular tumor unlikely to be constrained by nutrient availability. To further define this cancer-type-specific restriction, we studied activating mutations in mTOR. All mTOR mutants tested enhanced growth in a cell-type agnostic manner under nutrient-replete conditions but were detrimental to cell survival in nutrient-poor conditions. Consistently, analysis of tumor data demonstrated that oncogenic mutations in the nutrient-sensing arm of the mTOR pathway display a similar phenotype and were exceedingly rare in human cancers of all types. Together, these data suggest that maintaining the ability to turn off mTOR signaling in response to changing nutrient availability is retained in most naturally occurring tumors.

SIGNIFICANCE

This study suggests that cells need to inactivate mTOR to survive nutrient stress, which could explain the rarity of mTOR mutations and the limited clinical activity of mTOR inhibitors in cancer.

The diverse functions of FAT1 in cancer progression: good, bad, or ugly?

FAT atypical cadherin 1 (FAT1) is among the most frequently mutated genes in many types of cancer. Its highest mutation rate is found in head and neck squamous cell carcinoma (HNSCC), in which FAT1 is the second most frequently mutated gene. Thus, FAT1 has great potential to serve as a target or prognostic biomarker in cancer treatment. FAT1 encodes a member of the cadherin-like protein family. Under normal physiological conditions, FAT1 serves as a molecular "brake" on mitochondrial respiration and acts as a receptor for a signaling pathway regulating cell-cell contact interaction and planar cell polarity. In many cancers, loss of FAT1 function promotes epithelial-mesenchymal transition (EMT) and the formation of cancer initiation/stem-like cells. However, in some types of cancer, overexpression of FAT1 leads to EMT. The roles of FAT1 in cancer progression, which seems to be cancer-type specific, have not been clarified. To further study the function of FAT1 in cancers, this review summarizes recent relevant literature regarding this protein. In addition to phenotypic alterations due to FAT1 mutations, several signaling pathways and tumor immune systems known or proposed to be regulated by this protein are presented. The potential impact of detecting or targeting FAT1 mutations on cancer treatment is also prospectively discussed.

Long Noncoding RNA LEMD1-AS1 Increases LEMD1 Expression and Activates PI3K-AKT Pathway to Promote Metastasis in Oral Squamous Cell Carcinoma

Background. The survival rate of oral squamous cell carcinoma (OSCC) is only 50% due to a high incidence of metastasis. Long noncoding RNAs (lncRNAs) play a crucial role in OSCC genesis and progression, although their potential role in the metastasis of OSCC remains unclear. Methods. The transcriptome of 5 metastatic and 5 nonmetastatic OSCC samples were assessed by RNA sequencing. The biological functions and regulatory mechanisms of LEMD1-AS1 in OSCC were explored by in vitro and in vivo assays. Results. We identified 487 differentially expressed mRNAs (DEmRNAs) and 1507 differentially expressed lncRNAs (DElncRNAs) in OSCC with cervical lymph node (LN) metastasis relative to the nonmetastatic samples. In addition, both LEMD1-AS1 and its cognate LEMD1 were up-regulated in metastatic OSCC compared to nonmetastatic OSCC. Gain-of-function, loss-of-function, and rescue experiments indicated that LEMD1-AS1 upregulated LEMD1 to increase OSCC migration and invasion in vitro and in vivo. Mechanistically, LEMD1-AS1 stabilized LEMD1 and increased its mRNA and protein levels, and consequently activated the PI3K-AKT signaling pathway to facilitate OSCC metastasis. Conclusions. We established the lncRNA-mRNA landscape of metastatic OSCC, which indicated that LEMD1-AS1 enhanced OSCC metastasis by stabilizing its antisense transcript LEMD1. Thus, LEMD1-AS1 is a potential biomarker for predicting metastasis, as well as a therapeutic target of OSCC.

Simultaneously targeting ErbB family kinases and PI3K in HPV-positive head and neck squamous cell carcinoma

OBJECTIVES

To identify the most effective PI3K and EGFR inhibitors in HPV-positive head and neck squamous cell carcinoma (HNSCC) and investigate the efficacy of a combination of an ErbB family kinase inhibitor and a PI3K inhibitor to inhibit cell proliferation of HPV-positive HNSCC.

MATERIALS AND METHOD

HPV-positive HNSCC cell lines were treated with the FDA approved ErbB kinase inhibitor, Afatinib or FDA-approved PI3K inhibitor, Copanlisib, alone or in combination, and phosphorylation and total protein levels of cells were assessed by Western blot analysis.Cell proliferation and apoptosis were examined by MTS assay, flow cytometry, and Western blots, respectively.

RESULTS

Copanlisib more effectively inhibited cell proliferation in comparison to other PI3K inhibitors tested. HPV-positive HNSCC cells differentially responded to cisplatin, Afatinib, or Copanlisib. The combination of Afatinib and Copanlisib more effectively suppressed cell proliferation and induced apoptosis compared to either treatment alone. Mechanistically, the combination of Afatinib and Copanlisib completely blocked phosphorylation of EGFR, HER2, HER3, and Akt as well as significantly decreased the HPV E7 expression compared to either treatment alone.

CONCLUSION

Afatinib and Copanlisib more effectively suppress cell proliferation and survival of HPV-positive HNSCC in comparison to either treatment alone.

Paeoniflorigenone regulates apoptosis, autophagy, and necroptosis to induce anti-cancer bioactivities in human head and neck squamous cell carcinomas

ETHNOPHARMACOLOGICAL RELEVANCE

Paonia suffruticosa Andr. belonging to the family Paeoniaceae and has been used as a medicinal plant in Asian countries including China, Korea, and Japan. The roots of P. suffruticosa has been used in traditional medicine in various diseases including cancer and cardiovascular, female genital, and inflammatory diseases.

AIM OF THE STUDY

Head and neck squamous cell carcinomas (HNSCCs) pathologically account for 90% of all head and neck cancers. However, effective targeted therapies for HNSCCs are insufficient and the prognosis is very poor, especially in patients with metastatic HNSCCs. To overcome the current limitations of available therapies for HNSCCs, pathological approaches using natural compounds are attracting attention. Our study aimed to demonstrate the anti-cancer effects of paeoniflorigenone (Paeo, 98.9% purity) isolated from the root bark of P. suffruticosa.

MATERIALS AND METHODS

Our scientific methodology was performed as follows: cytotoxicity, morphological changes, and apototic DNA fragmentation were analyzed using MTT, light microscopy, and TUNEL assays. Protein expression, apoptosis, necroptosis, and autophagy were analyzed using Western blot and immunofluorescence assays. Cell migration and invasion were analyzed using wound healing and Boyden chamber assays.

RESULTS

We demonstrated that Paeo significantly reduced cell proliferation and cell division, leading to caspase-dependent apoptotic cell death in human YD-10B HNSCC cells. This result was associated with PI3K/AKT/mTOR/p70S6K signaling in these cells. In addition, we investigated other programmed cell death mechanisms associated with apoptosis and found that Paeo inhibited necroptosis via dephosphorylation of key necroptotic proteins (RIP and MLKL), whereas Paeo induced autophagy via increased LC3I/II expression and autophagosome formation in human YD-10B HNSCC cells. The anti-metastatic effects of Paeo significantly suppressed cell migration and invasion in human YD-10B HNSCC cells.

CONCLUSION

Overall, our results demonstrated that the bioactive compound, Paeo, exhibited anti-cancer bioactivities in human YD-10B HNSCC cells, suggesting that Paeo may be an attractive pathological approach for patients with human HNSCCs.

Expression profile of the PI3K-AKT-mTOR pathway in head and neck squamous cell carcinoma: Data from Brazilian population

OBJECTIVE

The phosphatidylinositol 3-kinase/protein kinase-B/mammalian target of the rapamycin (PI3K-AKT-mTOR) signaling pathway is an important regulator of cell proliferation, survival, and motility. The gain or loss of function of proteins related to this pathway results in the neoplastic transformation in several types of cancers. This study aimed to evaluate the expression profile of the PI3K-AKT-mTOR pathway in patients with head and neck squamous cell carcinoma (HNSCC) and HNSCC cell lines.

STUDY DESIGN

The study involved 26 formalin-fixed paraffin-embedded tissue samples from patients with HNSCC. The analysis of immunohistochemical expression of PI3K, AKT, p-mTOR, and phosphatase and tensin homolog (PTEN) proteins was performed by a quantitative assessment. The in vitro gene and protein expression evaluation was performed by real-time polymerase chain reaction and Western blot assay, respectively, in the human cell lines SCC-9 and FaDu.

RESULTS

High levels of PI3K, AKT, and p-mTOR were found in most HNSCC tumors. Following this result, we observed low amounts or absence of PTEN in most samples. Additionally, the FaDu cells (pharynx) showed higher AKT expression but lower expression of p-mTOR compared with SCC-9 cells (oral cavity), which hints at a loco-anatomical relevance.

CONCLUSION

Overall, this study found increased expression of the PI3K-AKT-mTOR pathway along with evident PTEN reduction in head and neck cancer.

Targeting Wee1 kinase to suppress proliferation and survival of cisplatin-resistant head and neck squamous cell carcinoma

PURPOSE

We investigated the role of Wee1 kinase in cisplatin-resistant head and neck squamous cell carcinoma (HNSCC) in multiple cisplatin-resistant HNSCC cell lines and determined the efficacy of either Wee1 inhibitor, AZD1775 alone, or in combination with cisplatin, on cisplatin-resistant HNSCC inhibition.

METHODS

Phosphorylation and total protein levels of cells were assessed by Western blot analysis. Cell viability and apoptosis were examined by MTS assay and flow cytometry, respectively.

RESULTS

Wee1 kinase protein expression levels in five cisplatin-resistant HNSCC cell types were higher than those in their parental cisplatin-sensitive partners. Importantly, Wee1 knockdown inhibited cell proliferation and re-sensitized cells to cisplatin treatment. Interestingly, previous studies have also shown that Wee1 inhibitor AZD1775 synergizes with cisplatin to suppress cell proliferation of cisplatin-sensitive HNSCC. We found that AZD1775 inhibited both cisplatin-sensitive and resistant HNSCC with similar IC₅₀ values, which suggested that AZD1775 could overcome cisplatin resistance in cisplatin-resistant HNSCC. Mechanistically, AZD1775 and cisplatin cooperatively induced DNA damage and apoptosis.

CONCLUSION

Wee1 inhibitor, AZD1775, and cisplatin coordinately suppressed proliferation and survival of HNSCC.

Assessing Long Non-coding RNAs in Tobacco-associated Oral Cancer

Cancer is one of the compelling and pegged diseases battled by clinicians and researchers worldwide. Among different types of cancer, oral cancer holds the sixth position globally. With an escalating prevalence in Asian countries, India, China, and Pakistan constitute a large proportion of total incidents of oral cancer patients in terms of new cases or deaths. This mounting prevalence is ascribed to poor oral hygiene and rampant use of substances earmarked as potential risk factors for the disease. Risk factors (dietary/lifestyle habits/occupational/environmental) trigger the activation of oncogenes, dysregulation of lncRNA and miRNA, and silence the tumor suppressor genes, which robustly contributes to the onset and progression of tumorigenesis in oral squamous cell carcinoma. Evidence suggests that specific carcinogens identified in tobacco and related products alter many cellular pathways predisposing to advanced stages of oral cancer. Long non-coding RNAs represent a broad group of heterogenous transcripts longer than 200 nucleotides which do not translate to form functional proteins. They regulate various cellular pathways by specifically interacting with other RNAs, DNA, and proteins. Their role in the pathogenesis of OSCC and other cancer is still being debated. In this review, we discuss the molecular insights of significant lncRNAs involved in some crucial deregulated pathways of tobacco-associated OSCC. The implications and challenges to harnessing the potential of lncRNAs as biomarkers in early diagnosis and targeted treatment have also been analyzed.

Loss of TACC1 variant25 inducing cell proliferation and suppressing autophagy in head and neck squamous carcinoma

Transforming acidic coiled-coil containing protein1 (TACC1) is closely related to transcription, translation and centrosome dynamics. Dysregulation of TACC1 is associated with multiple malignancies. Alternative splicing (AS) of TACC1 produces multiple variants, which are of great significance in cancer biology. However, the expression and biological functions of TACC1 variants in head and neck squamous cell carcinoma (HNSCC) remain unclear. In this study, we found for the first time that TACC1 variants exhibited a characteristic expression pattern and that TACC1 variant25 (TACC1v25) was downregulated in HNSCC tissues and cell lines. Overexpression of TACC1v25 in Cal27 and Fadu cells significantly inhibited proliferation and promoted autophagy. Moreover, expression levels of nuclear pERK and p-mTOR were significantly decreased, while the expression of Beclin-1 and the LC3II/LC3I ratio were increased in TACC1v25-overexpressed Cal27 and Fadu cells. After the addition of AKT activator SC79 to TACC1v25-overexpressed Cal27 and Fadu cells, the autophagy levels were remarkably rescued. In conclusion, TACC1v25 inhibits HNSCC progression through the ERK and AKT/mTOR pathways by inhibiting proliferation and increasing autophagy. TACC1v25 might have potential use as a tumour suppressor in HNSCC.

FERMT1 knockdown inhibits oral squamous cell carcinoma cell epithelial-mesenchymal transition by inactivating the PI3K/AKT signaling pathway

BACKGROUND

The metastasis of oral cancer is one of the main causes of death. However, the mechanisms underlying oral cancer metastasis have not been completely elucidated. Fermitin family member 1 (FERMT1) plays an -oncogene role in many cancers; however, the role of FERMT1 in oral squamous cell cancer (OSCC) remains unclear.

METHODS

In this study, OSCC cells were treated with 5 ng/ml recombinant human Transforming growth factor-β1 (TGF-β1) protein. FERMT1 expression was measured in OSCC cell lines by RT-qPCR and western blotting. The effect of FERMT1 knockdown on the migration and invasion of OSCC cells was evaluated by Transwell assay. The epithelial-mesenchymal transition (EMT) and PI3K/AKT signaling pathway-related mRNA expression and protein levels were assessed by RT-qPCR and western blotting.

RESULTS

We found that FERMT1 expression was elevated in TGF-β1-induced OSCC cell lines, and knockdown of FERMT1 inhibited the migration and invasion in TGF-β1-induced OSCC cells. FERMT1 silencing inhibited vimentin, N-cadherin, matrix metalloproteinase 9 (MMP-9) expression and promoted E-cadherin expression, suggesting that FERMT1 silencing inhibited EMT in TGF-β1-induced OSCC cells. Furthermore, FERMT1 silencing inactivated the PI3K/AKT signaling pathway in TGF-β1-induced OSCC cells. Activation of the PI3K/AKT signaling pathway reversed the effect of FERMT1 silencing on OSCC cell migration, invasion, and EMT.

CONCLUSIONS

FERMT1 silencing inhibits the migration, invasion, and EMT of OSCC cells via inactivation of the PI3K/AKT signaling pathway, suggesting that FERMT1 is a novel and potential therapeutic target for anti-metastatic strategies for OSCC.

Therapeutic strategies for systemic therapies of human papillomavirus-related oropharyngeal cancer

Our understanding of human papillomavirus (HPV)-related oropharyngeal cancer (OPC) and its molecular basis continues to evolve and produce important insights into customized therapeutic strategies. Novel therapeutics exploiting HPV-related targets are being evaluated in the incurable setting, while the favorable prognosis of locoregionally advanced disease has stimulated investigation into de-escalation strategies. There is much opportunity for better personalization of standard therapy according to HPV status. This review discusses both current and investigational therapeutic strategies for HPV-related OPC.

Hypomethylation and downregulation of miR-23b-3p are associated with upregulated PLAU: a diagnostic and prognostic biomarker in head and neck squamous cell carcinoma

Background

DNA methylation and miRNA-target genes play an important part in the early development of various tumors and have been studied as tumor biomarkers. Although previous studies have reported a cluster of molecular events (such as aberrant alterations of genomics and epigenetics), little is known of the potential biomarkers for early diagnosis and prognostic evaluation in head and neck squamous cell carcinoma (HNSCC).

Methods

Multiple bioinformatics tools based on The Cancer Genome Atlas (TCGA) database and clinical samples were applied to evaluate the beneficial biomarkers in HNSCC. We focused on the role of plasminogen activator urokinase (PLAU), including diagnostic and prognostic significance, gene expression analysis, aberrant DNA methylation characteristics, interaction of miRNAs and associated signaling pathways.

Results

We found that PLAU was aberrantly upregulated in HNSCC, regardless of the mRNA or protein level. The results of receiver operating characteristic (ROC) curve and Cox regression analysis revealed that PLAU was a diagnostic and independent prognostic factor for patients with HNSCC. Hypomethylation of PLAU was closely related to poor survival in HNSCC. Additionally, miR-23b-3p was predicted to target PLAU and was significantly downregulated in HNSCC tissues. Therefore, our findings suggested that PLAU functioned as a promoter in the pathological process of HNSCC. DNA hypomethylation and downregulation of miR-23b-3p were associated with PLAU overexpression. Finally, our findings provided evidence of a significant interaction between PLAU-target and miRNAs-target pathways, indicating that miR-23b-3p suppresses malignant properties of HNSCC by targeting PLAU via Ras/MAPK and Akt/mTOR signaling pathways.

Conclusions

PLAU is overexpressed and may serve as an independent diagnostic and prognostic biomarker in HNSCC. Hypomethylation and downregulation of miR-23b-3p might account for the oncogenic role of PLAU in HNSCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02251-w.

The Role of Akt in Acquired Cetuximab Resistant Head and Neck Squamous Cell Carcinoma: An In Vitro Study on a Novel Combination Strategy

The epidermal growth factor receptor (EGFR) is a therapeutic target in head and neck squamous cell carcinoma (HNSCC). Resistance to EGFR-targeted therapies, such as cetuximab, poses a challenging problem. This study aims to characterize acquired cetuximab resistance mechanisms in HNSCC cell lines by protein phosphorylation profiling. Through this, promising combination treatments can be identified to possibly overcome acquired cetuximab resistance in HNSCC. Protein phosphorylation profiling showed increased phosphorylation of Akt1/2/3 after cetuximab treatment in acquired cetuximab resistant cells compared to cetuximab sensitive cells, which was confirmed by western blotting. Based on this protein phosphorylation profile, a novel combination treatment with cetuximab and the Akt1/2/3 inhibitor MK2206 was designed. Synergy between cetuximab and MK2206 was observed in two cetuximab sensitive HNSCC cell lines and one acquired cetuximab resistant variant in simultaneous treatment schedules. In conclusion, this study demonstrates that increased Akt1/2/3 phosphorylation seems to be characteristic for acquired cetuximab resistance in HNSCC cell lines. Our results also show an additive to synergistic interaction between cetuximab and MK2206 in simultaneous treatment schedules. These data support the hypothesis that the combination of cetuximab with PI3K/Akt pathway inhibition might be a promising novel therapeutic strategy to overcome acquired cetuximab resistance in HNSCC patients.

Bile reflux and hypopharyngeal cancer (Review)

Laryngopharyngeal reflux, a variant of gastroesophageal reflux disease, has been considered a risk factor in the development of hypopharyngeal cancer. Bile acids are frequently present in the gastroesophageal refluxate and their effect has been associated with inflammatory and neoplastic changes in the upper aerodigestive tract. Recent in vitro and in vivo studies have provided direct evidence of the role of acidic bile refluxate in hypopharyngeal carcinogenesis and documented the crucial role of NF-κB as a key mediator of early oncogenic molecular events in this process and also suggested a contribution of STAT3. Acidic bile can cause premalignant changes and invasive squamous cell cancer in the affected hypopharynx accompanied by DNA damage, elevated p53 expression and oncogenic mRNA and microRNA alterations, previously linked to head and neck cancer. Weakly acidic bile can also increase the risk for hypopharyngeal carcinogenesis by inducing DNA damage, exerting anti-apoptotic effects and causing precancerous lesions. The most important findings that strongly support bile reflux as an independent risk factor for hypopharyngeal cancer are presented in the current review and the underlying mechanisms are provided.

Current Insights and Advancements in Head and Neck Cancer: Emerging Biomarkers and Therapeutics with Cues from Single Cell and 3D Model Omics Profiling

Head and neck cancer (HNC) is among the ten leading malignancies worldwide, with India solely contributing one-third of global oral cancer cases. The current focus of all cutting-edge strategies against this global malignancy are directed towards the heterogeneous tumor microenvironment that obstructs most treatment blueprints. Subsequent to the portrayal of established information, the review details the application of single cell technology, organoids and spheroid technology in relevance to head and neck cancer and the tumor microenvironment acknowledging the resistance pattern of the heterogeneous cell population in HNC. Bioinformatic tools are used for study of differentially expressed genes and further omics data analysis. However, these tools have several challenges and limitations when analyzing single-cell gene expression data that are discussed briefly. The review further examines the omics of HNC, through comprehensive analyses of genomics, transcriptomics, proteomics, metabolomics, and epigenomics profiles. Patterns of alterations vary between patients, thus heterogeneity and molecular alterations between patients have driven the clinical significance of molecular targeted therapies. The analyses of potential molecular targets in HNC are discussed with connotation to the alteration of key pathways in HNC followed by a comprehensive study of protein kinases as novel drug targets including its ATPase and additional binding pockets, non-catalytic domains and single residues. We herein review, the therapeutic agents targeting the potential biomarkers in light of new molecular targeted therapies. In the final analysis, this review suggests that the development of improved target-specific personalized therapies can combat HNC's global plight.

Antitumor Activity of Nanoparticles Loaded with PHT-427, a Novel AKT/PDK1 Inhibitor, for the Treatment of Head and Neck Squamous Cell Carcinoma

Currently, new treatments are required to supplement the current standard of care for head and neck squamous cell carcinoma (HNSCC). The phosphatidylinositol3-kinase (PI3K) signaling pathway is commonly altered and activated in HNSCC. PHT-427 is a dual PI3K-mammalian target of the AKT/PDK1 inhibitor; however, to the best of our knowledge, the effect of the PHT-427 inhibitor on HNSCC has not been investigated. This study aims to evaluate the antitumoral effect of PHT-427-loaded polymeric nanoparticles based on α-tocopheryl succinate (α-TOS). The in vitro activity of PHT-427 was tested in hypopharynx carcinoma squamous cells (FaDu) to measure the cell viability, PI3KCA/AKT/PDK1 gene expression, and PI3KCA/AKT/PDK1 levels. Apoptosis, epidermal growth factor receptor (EGFR), and reactive oxygen species (ROS) were also measured. The presence of PHT-427 significantly enhances its antiproliferative and proapoptotic activity by inactivating the PI3K/AKT/PDK1 pathway. Nanoparticles (NPs) effectively suppress AKT/PDK1 expression. Additionally, NPs loaded with PHT-427 produce high oxidative stress levels that induce apoptosis. In conclusion, these results are promising in the use of this nanoformulation as a PHT-427 delivery system for effective HNSCC treatment.

The combinatorial inhibition of Wnt signaling and Akt kinase is beneficial for reducing the survival and glycolytic activity of tongue cancer cells

BACKGROUND

Wnt signaling is important in the development of head and neck squamous cell carcinomas (HNSCC); however, Wnt pathway inhibitors lack satisfactory potency when used in monotherapy. The aim of this study was to assess the effects of the combinations of Wnt-signaling inhibitors and the inhibitor of Akt kinase on the survival and glycolytic activity of tongue carcinoma cells.

METHODS

CAL27, SCC-25, and BICR22 tongue cancer cell lines were used. Cells were treated with Wnt signaling (PRI-724 and IWP-O1) and Akt-kinase inhibitors. The effect of the chemicals on cell viability and cytotoxicity were evaluated by MTS and CellTox Green assays, respectively. Cell cycle distribution was analyzed cytometrically after propidium iodide staining. Annexin V binding to externalized phosphatidylserine and analysis of mitochondrial potential allowed the assessment of apoptosis. Glucose uptake and lactate release were evaluated luminometrically. Additionally, the viability of cells in spheroids was analyzed based on ATP content.

RESULTS

The Akt-kinase inhibitor showed significant cytotoxicity toward primary cancer cells. Moreover, its pro-apoptotic effects were enhanced by Wnt-pathway inhibitors. The activity of Akt inhibitor was even higher (by twofold) in 3D spheroids in comparison to cells grown in monolayer. The synergistic reduction in the growth of spheroids was observed between Akt inhibitor and IWP-O1. Reduced glucose consumption may play a part in the combinatorial effects of these chemicals.

CONCLUSION

The results point to the therapeutic potential of the combinatorial use of Wnt inhibitors together with Akt inhibitors in HNSCC.

Stomach-specific c-Myc overexpression drives gastric adenoma in mice through AKT/mammalian target of rapamycin signaling

Gastric cancer (GC) is one of the most common malignant cancers in the world. c-Myc, a well-known oncogene, is commonly amplified in many cancers, including gastric cancer. However, it is still not completely understood how c-Myc functions in GC. Here, we generated a stomach-specific c-Myc transgenic mouse model to investigate its role in GC. We found that overexpression of c-Myc in Atp4b+ gastric parietal cells could induce gastric adenoma in mice. Mechanistically, c-Myc promoted tumorigenesis via the AKT/mTOR pathway. Furthermore, AKT inhibitor (MK-2206) or mTOR inhibitor (Rapamycin) inhibited the proliferation of c-Myc overexpressing gastric cancer cell lines. Thus, our findings highlight that gastric tumorigenesis can be induced by c-Myc overexpression through activation of the AKT/mTOR pathway.

Differences in Extracellular Vesicle Protein Cargo Are Dependent on Head and Neck Squamous Cell Carcinoma Cell of Origin and Human Papillomavirus Status

To identify potential extracellular vesicle (EV) biomarkers in head and neck squamous cell carcinoma (HNSCC), we evaluated EV protein cargo and whole cell lysates (WCL) from HPV-positive and -negative HNSCC cell lines, as well as normal oral keratinocytes and HPV16-transformed cells. EVs were isolated from serum-depleted, conditioned cell culture media by polyethylene glycol (PEG) precipitation/ultracentrifugation. EV and WCL preparations were analyzed by LC-MS/MS. Candidate proteins detected at significantly higher levels in EV compared with WCL, or compared with EV from normal oral keratinocytes, were identified and confirmed by Wes Simple Western protein analysis. Our findings suggest that these proteins may be potential HNSCC EV markers as proteins that may be (1) selectively included in EV cargo for export from the cell as a strategy for metastasis, tumor cell survival, or modification of tumor microenvironment, or (2) representative of originating cell composition, which may be developed for diagnostic or prognostic use in clinical liquid biopsy applications. This work demonstrates that our method can be used to reliably detect EV proteins from HNSCC, normal keratinocyte, and transformed cell lines. Furthermore, this work has identified HNSCC EV protein candidates for continued evaluation, specifically tenascin-C, HLA-A, E-cadherin, EGFR, EPHA2, and cytokeratin 19.

Attacking the PI3K/Akt/mTOR signaling pathway for targeted therapeutic treatment in human cancer

Cancer is the second leading cause of human death globally. PI3K/Akt/mTOR signaling is one of the most frequently dysregulated signaling pathways observed in cancer patients that plays crucial roles in promoting tumor initiation, progression and therapy responses. This is largely due to that PI3K/Akt/mTOR signaling is indispensable for many cellular biological processes, including cell growth, metastasis, survival, metabolism, and others. As such, small molecule inhibitors targeting major kinase components of the PI3K/Akt/mTOR signaling pathway have drawn extensive attention and been developed and evaluated in preclinical models and clinical trials. Targeting a single kinase component within this signaling usually causes growth arrest rather than apoptosis associated with toxicity-induced adverse effects in patients. Combination therapies including PI3K/Akt/mTOR inhibitors show improved patient response and clinical outcome, albeit developed resistance has been reported. In this review, we focus on revealing the mechanisms leading to the hyperactivation of PI3K/Akt/mTOR signaling in cancer and summarizing efforts for developing PI3K/Akt/mTOR inhibitors as either mono-therapy or combination therapy in different cancer settings. We hope that this review will facilitate further understanding of the regulatory mechanisms governing dysregulation of PI3K/Akt/mTOR oncogenic signaling in cancer and provide insights into possible future directions for targeted therapeutic regimen for cancer treatment, by developing new agents, drug delivery systems, or combination regimen to target the PI3K/Akt/mTOR signaling pathway. This information will also provide effective patient stratification strategy to improve the patient response and clinical outcome for cancer patients with deregulated PI3K/Akt/mTOR signaling.

Head and neck cancer: Current challenges and future perspectives

Head and neck cancers are a heterogeneous, aggressive and genetically complex collection of malignancies of the oral cavity, nasopharynx, oropharynx, hypopharynx, larynx, paranasal sinuses and salivary glands, which are difficult to treat. About 90% of all head and neck cancers are squamous cell carcinomas (HNSCC). Larynx and Oral cavity carcinomas are generally related with tobacco consumption, alcohol abuse (or both), but pharynx carcinomas are generally associated with infection of human papillomavirus (HPV), especially HPV-16 subtype. Thus, usually HNSCC can be separated into HPV-negative and HPV-positive categories. Despite substantial efforts invested into therapeutic development of HNSCC, the 5-year survival rate of patients with HNSCC still remains dismal. The primary reason being late diagnosis, recurrent metastasis, relapse and resistance to therapies. Currently surgery and radiotherapy represent the baseline treatment options for most initial stage HNSCC patients, but these treatments are associated with significant morbidity and poor prognosis. Moreover, the issue of resistance to both radiotherapy/chemotherapy and recurrent relapse are common in HNSCC. Elucidation of the genetic landscape, tumor microenvironment and aberrant signaling pathways have generated new insights into the molecular pathogenesis of this disease. Thus, the scientific research has therefore been focused on the understanding of HNSCC biology and immunobiology to identification of predictive/prognostic biomarkers, which will be key to develop more effective targeted therapies with less toxicity and high specificity.

Targeting the genetic landscape of oral potentially malignant disorders has the potential as a preventative strategy in oral cancer

This study reviews the molecular landscape of oral potentially malignant disorders (OPMD). We examine the impact of tumour heterogeneity, the spectrum of driver mutations (TP53, CDKN2A, TERT, NOTCH1, AJUBA, PIK3CA, CASP8) and gene transcription on tumour progression. We comment on how some of these mutations impact cellular senescence, field cancerization and cancer stem cells. We propose that OPMD can be monitored more closely and more dynamically through the use of liquid biopsies using an appropriate biomarker of transformation. We describe new gene interactions through the use of a systems biology approach and we highlight some of the first studies to identify functional genes using CRISPR-Cas9 technology. We believe that this information has translational implications for the use of re-purposed existing drugs and/or new drug development. Further, we argue that the use of digital technology encompassing clinical and laboratory-based data will create relevant datasets for machine learning/artificial intelligence. We believe that therapeutic intervention at an early molecular premalignant stage should be an important preventative strategy to inhibit the development of oral squamous cell carcinoma and that this approach is applicable to other aerodigestive tract cancers.

Recent insights in the PI3K/Akt pathway as a promising therapeutic target in combination with EGFR-targeting agents to treat head and neck squamous cell carcinoma

Resistance to therapies targeting the epidermal growth factor receptor (EGFR), such as cetuximab, remains a major roadblock in the search for effective therapeutic strategies in head and neck squamous cell carcinoma (HNSCC). Due to its close interaction with the EGFR pathway, redundant or compensatory activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway has been proposed as a major driver of resistance to EGFR inhibitors. Understanding the role of each of the main proteins involved in this pathway is utterly important to develop rational combination strategies able to circumvent resistance. Therefore, the current work reviewed the role of PI3K/Akt pathway proteins, including Ras, PI3K, tumor suppressor phosphatase and tensing homolog, Akt and mammalian target of rapamycin in resistance to anti-EGFR treatment in HNSCC. In addition, we summarize PI3K/Akt pathway inhibitors that are currently under (pre)clinical investigation with focus on overcoming resistance to EGFR inhibitors. In conclusion, genomic alterations in and/or overexpression of one or more of these proteins are common in both human papillomavirus (HPV)-positive and HPV-negative HNSCC tumors. Therefore, downstream effectors of the PI3K/Akt pathway serve as promising drug targets in the search for novel therapeutic strategies that are able to overcome resistance to anti-EGFR treatment. Co-targeting EGFR and the PI3K/Akt pathway can lead to synergistic drug interactions, possibly restoring sensitivity to EGFR inhibitors and hereby improving clinical efficacy. Better understanding of the predictive value of PI3K/Akt pathway alterations is needed to allow the identification of patient populations that might benefit most from these combination strategies.

Pepsin Promotes Activation of Epidermal Growth Factor Receptor and Downstream Oncogenic Pathways, at Slightly Acidic and Neutral pH, in Exposed Hypopharyngeal Cells

Pepsin refluxate is considered a risk factor for laryngopharyngeal carcinogenesis. Non-acidic pepsin was previously linked to an inflammatory and tumorigenic effect on laryngopharyngeal cells in vitro. Yet there is no clear evidence of the pepsin-effect on a specific oncogenic pathway and the importance of pH in this process. We hypothesized that less acidic pepsin triggers the activation of a specific oncogenic factor and related-signalling pathway. To explore the pepsin-effect in vitro, we performed intermittent exposure of 15 min, once per day, for a 5-day period, of human hypopharyngeal primary cells (HCs) to pepsin (1 mg/mL), at a weakly acidic pH of 5.0, a slightly acidic pH of 6.0, and a neutral pH of 7.0. We have documented that the extracellular environment at pH 6.0, and particularly pH 7.0, vs. pH 5.0, promotes the pepsin-effect on HCs, causing increased internalized pepsin and cell viability, a pronounced activation of EGFR accompanied by NF-κB and STAT3 activation, and a significant upregulation of EGFR, AKT1, mTOR, IL1β, TNF-α, RELA(p65), BCL-2, IL6 and STAT3. We herein provide new evidence of the pepsin-effect on oncogenic EGFR activation and its related-signaling pathway at neutral and slightly acidic pH in HCs, opening a window to further explore the prevention and therapeutic approach of laryngopharyngeal reflux disease.

Genetic variants associated with expression of TCF19 contribute to the risk of head and neck cancer in Chinese population

BACKGROUND

Squamous cell carcinoma of the head and neck (SCCHN) is one of the most common cancers worldwide and includes cancers arising from the oral cavity, pharynx and larynx. Genome-wide association studies have found several genetic variants related to the risk of SCCHN; however, they could only explain a small fraction of the heritability. Thus, more susceptibility loci associated with SCCHN need to be identified.

METHODS

An association study was conducted by genotyping 555 patients with SCCHN and 1367 controls in a Chinese population. Single-variant association analysis was conducted on 63 373 SNPs, and the promising variants were then confirmed by a two-stage validation with 1875 SCCHN cases and 4637 controls. Bioinformatics analysis and functional assays were applied to uncover the potential pathogenic mechanism of the promising variants and genes associated with SCCHN.

RESULTS

We first identified three novel genetic variants significantly associated with the risk of SCCHN (p=7.45×10^-7 for rs2517611 at 6p22.1, p=1.76×10^-9 for rs2524182 at 6p21.33 and p=2.17×10^-10 for rs3131018 at 6p21.33). Further analysis and biochemical assays showed that rs3094187, which was in a region in high linkage disequilibrium with rs3131018, could modify TCF19 expression by regulating the binding affinity of the transcription factor SREBF1 to the promoter of TCF19. In addition, experiments revealed that the inhibition of TCF19 may affect several important pathways involved in tumourigenesis and attenuate the cell proliferation and migration of SCCHN.

CONCLUSION

These findings offer important evidence that functional genetic variants could contribute to development of SCCHN and that TCF19 may function as a putative susceptibility gene for SCCHN.