Head And Neck Squamous Cell Carcinoma Cell Growth Research Articles

Regulatory Effects of SLC7A2-CPB2 on Lymphangiogenesis: A New Approach to Suppress Lymphatic Metastasis in HNSCC.

Lymph node metastasis (LNM) is a critical factor affecting the outcomes of head and neck squamous cell carcinoma (HNSCC) and the main reason for treatment failure. This study was designed to examine the effects of the key genes involved in the LNM of HNSCC. Tissue samples (HNSCC) were examined by transcriptome sequencing, and the core genes associated with LNM were detected via bioinformatics analysis. The functions of these core genes were then validated using the TCGA biological database and their effects on the propagation, invasion, and metastasis of HNSCC cells were evaluated through cell culture experiments. Moreover, the effect of core gene expression on the LNM capability of HNSCC was confirmed via a footpad xenograft mice model. In the findings, a key gene involved in the LNM of HNSCC was identified as SLC7A2. It was correlated with adverse clinical prognosis and expressed with low expression in HNSCC tissues. As shown in cell culture experiments, FaDu and SCC15 cell growth, invasion, and migration were inhibited when SLC7A2 was overexpressed. Further, cell apoptosis was stimulated, and lymphangiogenesis was suppressed through the downregulation of CPB2 expression. Animal studies demonstrated that the growth and LNM of HNSCC cells were inhibited by SLC7A2 overexpression. It is concluded that SLC7A2 is involved in HNSCC lymphatic metastasis by controlling CPB2 function. The results are anticipated to offer new directions for the effective treatment of HNSCC.

The Notch inhibitor, FLI-06, increases the chemosensitivity of head and neck Squamous cell carcinoma cells to taxanes-based treatment

Aberration of Notch signaling is one of the key events involved in the development and progression of head and neck squamous cell carcinoma (HNSCC). The Notch pathway controls the tissue-specific differentiation of normal squamous epithelial cells and is frequently altered in squamous carcinomas, thus affecting their proliferation, growth, survival, and chemosensitivity or resistance against anti-cancer agents. In this study, we show that the use of novel, small-molecule inhibitors of Notch signaling, such as FLI-06, can have a beneficial effect on increasing the chemosensitivity of HNSCC to taxane-based chemotherapy. Inhibition of Notch signaling by FLI-06 alone virtually blocks the proliferation and growth of HNSCC cells in both 2D and 3D cultures and the zebrafish model, which is accompanied by down-regulation of key Notch target genes and proteins. Mechanistically, FLI-06 treatment causes cell cycle arrest in the G1-phase and induction of apoptosis in HNSCC, which is accompanied by increased c-JunS63 phosphorylation. Combining FLI-06 with Docetaxel shows a synergistic effect and partially blocks the cell growth of aggressive HNSCC cells via enhanced apoptosis and modification of c-JunS243 phosphorylation via GSK-3β inhibition. In conclusion, inhibition of Notch signaling in HNSCC cells that retain active Notch signaling significantly supports taxane-based anticancer activities via modulation of both the GSK-3β and the c-Jun.

Abstract 4517: Novel chemical degraders targeting NSD2 in head and neck squamous cell carcinoma (HNSCC)

Abstract Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide. Despite advances in treatments and significant efficacy of immunotherapy drugs in HNSCC, no effective targeted therapies have been approved in this disease yet. NSD2 is a histone lysine methyltransferase, which is overexpressed in HNSCC and is implicated in tumor growth, cell cycle regulation, epithelial-mesenchymal transition (EMT) and metastasis not only in HNSCC, but also in many other solid tumors. Development of inhibitors to the catalytic activity of NSD2 has been rather limited to date, which necessitates an alternative approach. To target NSD2, we have recently developed a series of novel proteolysis targeting chimeras (PROTACs), which chemically degrade NSD2 utilizing native cellular machinery - ubiquitin-proteasome system - with VHL as an E3 ligase. A series of >40 compounds were tested in HNSCC cell lines (JHU-011 and FaDu) and NSD2-dependent multiple myeloma cell line (KMS11) for degradation activity against NSD2 protein, and H3K36me2 chromatin mark reduction, using Western blot. We also tested their anti-proliferative activity in cell viability assay (CTB) and clonogenic assay. Compounds NUCC-0227381, NUCC-0227384, NUCC-0227414 and NUCC-0227383 show promising results by reducing NSD2 and H3K36me2 levels. NUCC-0227383 compound was highly promising, as it was the most potent in reducing NSD2/K36me2 levels without affecting NSD1/NSD3 levels and had profound effects on HNSCC cell growth. Lead compound NUCC-0227383 was chosen for further testing and in preliminary testing, showed a dose-dependent, VHL-mediated, and proteasome dependent function. Proteomics analysis, testing for specificity of NUCC-0227383 against a panel of histone methyltransferases, and in vivo testing of this promising compound against HNSCC is planned. Citation Format: Amr Ismail, Ekaterina Roshchina, Iuliia Topchu, Gary Schiltz, Yanis Boumber. Novel chemical degraders targeting NSD2 in head and neck squamous cell carcinoma (HNSCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4517.

Abstract 1219: In vivo delivery of CRISPR-Cas9 using lipid nanoparticles enables ATAD3A gene depletion to enhance RAS-targeted therapy

Abstract Targeting mitochondrial oncoproteins presents a new concept in developing effective cancer therapeutics. ATAD3A is a nuclear-encoded mitochondrial enzyme that contributes to mitochondrial dynamics, cholesterol metabolism, and signal transduction. Our previous study has demonstrated elevated expression of ATAD3A in head and neck squamous cell carcinoma (HNSCC) primary tissues and cultured cell lines. Loss of function suppresses HNSCC cell growth and elicits tumor regression in orthotopic tumor-bearing mice. Mechanistically, ATAD3A interacts with ERK1/2 in the mitochondria of HNSCC cells in the presence of VDAC1, and the ATAD3A-ERK1/2 signaling axis drives HNSCC development in a RAS-independent fashion. CRISPR-Cas9 has revolutionized genome engineering and has been intensively used to modify cancer-associated genes. However, challenges remain as CRISPR editing components must be transported into cells to exert their function. There is a need to explore effective in vivo delivery systems to accelerate the clinical use of CRISPR-Cas9. As no drug is available to target ATAD3A directly, we developed CRISPR-based ATAD3A-targeting nanodrugs by loading Cas9 mRNA and anti-ATAD3A sgRNAs into lipid nanoparticles (LNPs) that have become clinically acceptable delivery system due to low toxicity and high delivery efficacy and biocompatibility. As expected, treatment tongue tumors established in NSG mice with LNP-sgATAD3A remarkably repressed tumor growth. Most interestingly, the addition of LNP-sgATAD3A to the RAS inhibitor salirasib potentiated anticancer activity for HNSCC compared with the efficacy resulting from single-arm treatment. These novel and significant findings demonstrate a novel approach to inhibiting ATAD3A in tumor cells and provide a possible therapeutic strategy to enhance the success of multimodality therapy in cancer patients. Citation Format: Fanghui Chen, Liwei Lang, Yamin Li, Wei Zheng, Yong Teng. In vivo delivery of CRISPR-Cas9 using lipid nanoparticles enables ATAD3A gene depletion to enhance RAS-targeted therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1219.

Diallyl Trisulfide Induces ROS-Mediated Mitotic Arrest and Apoptosis and Inhibits HNSCC Tumor Growth and Cancer Stemness.

Despite advances in therapeutic approaches, the five-year survival rate for head and neck squamous cell carcinoma (HNSCC) patients is still less than fifty percent. Research has indicated that the consumption of Allium vegetables or processed garlic containing diallyl trisulfide (DATS) can lower the risk of multiple types of cancer. Nevertheless, the effectiveness and underlying mechanisms of DATS against HNSCC have not been thoroughly explored until the current study. In this research, it was found that DATS notably curtailed the growth and viability of HNSCC cells. Additionally, DATS triggered a significant G2/M cell cycle arrest in these cells, accumulating cyclin B1, Cip1/p21, and Ser-10 phospho-histone H3-this was indicative of mitotic arrest attenuated by NAC pretreatment, suggesting the role of reactive oxygen species (ROS) induction. The production of ROS induced by DATS led to DNA damage and apoptosis, a process associated with elevated levels of cleaved caspase-3 and cleaved PARP, along with reduced XIAP. When HNSCC cells were exposed to pharmacological concentrations of DATS, it resulted in the suppression of cancer stem cell (CSC) populations, as indicated by a decrease in the CD133high/CD44high cell fraction, reduced aldehyde dehydrogenase 1 (ALDH1) activity, inhibited spheroid formation and downregulated SOX2 and Oct4 expression. Furthermore, the administration of DATS to tumor xenografts demonstrated its in vivo capacity to hinder CSCs. Further, DATS treatment inhibited the growth of UMSCC-22B head and neck cancer tumor xenograft in immunocompromised mice. Overall, DATS inhibited cell proliferation; induced cell cycle mitotic arrest and apoptosis involving DNA damage through ROS generation; reduced the CSC fraction and spheroid formation; and downregulated SOX2 and Oct4 expression. More importantly, DATS inhibited HNSCC tumor growth and CSC fraction in vivo. Thus, DATS could be a potential anticancer agent that can be used against head and neck cancer.

Long non-coding RNA LINC00491 accelerates head and neck squamous cell carcinoma progression through regulating miR-508-3p/SATB1 axis and activating Wnt signaling pathway

Head and neck squamous cell carcinoma (HNSCC) is the most common malignancy of the head and neck epidermis. Accumulating long non-coding RNAs (lncRNAs) have been proven to be involved in the occurrence and development of HNSCC. LncRNA long intergenic non-protein coding RNA 491 (LINC00491) has been confirmed to regulate the progression of some cancers. In our study, we aimed to explore the potential biological function of LINC00491 and expound the regulatory mechanism by which LINC00491 affects the progression of HNSCC. RT-qPCR was utilized to analyze the expression of LINC00491 in HNSCC cell lines and the normal cell line. Functionally, we carried out a series of assays to measure cell proliferation, apoptosis, migration and invasion, such as EdU assay, colony formation, wound healing and western blot assays. Also, mechanism assays including RNA pull down and RIP were also implemented to investigate the interaction of LINC00491 and RNAs. As a result, we discovered that LINC00491 was highly expressed in HNSCC cells. In addition, LINC00491 depletion suppressed cell proliferation, migration and EMT process. Furthermore, we discovered that LINC00491 could bind to miR-508-3p. MiR-508-3p overexpression can restrain HNSCC cell growth. Importantly, miR-508-3p can target SATB homeobox 1 (SATB1) in HNSCC cells. Further, Wnt signaling pathway was proved to be activated by LINC00491 through SATB1 in HNSCC cells. In a word, LINC00491 accelerated HNSCC progression through regulating miR-508-3p/SATB1 axis and activating Wnt signaling pathway.

Prognosis of Midkine and AT1R expression in resectable head and neck squamous cell carcinoma

BackgroundResearch studies have demonstrated that Midkine (MDK) can influence the expression and activity of Renin-angiotensin system (RAS) components. Angiotensin II is involved in tumor growth and angiogenesis in different cancers. We previously observed Angiotensin II receptor blockers (ARBs) improve the survival rates of patients with oral cancers. These findings have prompted us to investigate whether MDK can influence the RAS pathway, mainly through its association with angiotensin II type 1 receptor (AT1R), which contributes to the observed poor prognosis in head and neck squamous cell carcinoma (HNSCC) patients.MethodsMDK and AT1R expressions were examined in 150 HNSCC patients post-operation by immunohistochemical staining between 1 January 2010 and 31 December 2016. We tested the over-expression and silencing of MDK to evaluate the AT1R expression and functional biological assays in HNSCC cell lines HSC-3 and SAS.ResultsPositive expression of MDK is correlated with positive AT1R expression. MDK predicted poor NSCC patients’ survival. Silencing MDK could suppress AT1R and pAKT expression and reduce the growth, migration, and invasion of HNSCC cells. ARB also inhibits MDK stimulating HNSCC cell proliferation. Overexpression of MDK could upregulate AT1R and pAKT.ConclusionsMDK is an independent prognostic factor of HNSCC post-operation, and AT1R regulates HNSCC cell growth, invasion, and migration. Positive MDK and AT1R expressions are highly correlated. Mechanistically, the interaction between MDK and AT1R is crucial for MDK-mediated cell viability, and inhibiting AT1R can effectively counteract or abolish these effects. Furthermore, MDK exerts a regulatory role in the expression of AT1R, as well as in the growth and motility of HNSCC cells. These findings highlight the involvement of the interaction between MDK, AT1R, and the pAkt signaling pathways in HNSCC cell viability growth.

MiR-526b-3p enhances sensitivity of head and neck squamous cell carcinoma cells to radiotherapy via suppressing exosomal LAMP3-mediated autophagy

Lysosomal associated membrane protein 3 (LAMP3) has been reported to be a tumour promoter in multiple cancer types by modulating tumour cell autophagy. However, the potential mechanism of LAMP3 in radio-resistance of head and neck squamous cell carcinoma (HNSCC) remains unknown. Therefore, our current study aims to detect the impacts of LAMP3 on the resistance of HNSCC cells to radiotherapy and meanwhile explore its functional mechanism. Through RT-Qpcr examination, LAMP3 expression was identified to be expressed at a significantly high level in irradiation-resistant HNSCC cell lines compared with irradiation-sensitive HNSCC cell lines. Functional assays including CCK-8, colony formation and Transwell assays demonstrated that LAMP3 enhanced the radio-resistance through inducing autophagy to promote HNSCC cell growth. Furthermore, irradiation-resistant HNSCC cells could transfer exosomal LAMP3 to elevate LAMP3 expression in irradiation-sensitive HNSCC cells. Mechanistically, microRNA (miRNA) miR-526b-3p could inhibit LAMP3 expression so as to strengthen sensitivity of HNSCC cells to radiotherapy. In a word, exosomal LAMP3 expression promoted radioresistance of HNSCC cells via inducing autophagy, while this effect could be suppressed by miR-526b-3p in a targeted manner.

Abstract 2832: Plk1 signaling as a therapeutic target for HPV- head and neck cancer

Abstract Current frontline chemotherapy and radiotherapy for head and neck cancer (HNC) is insufficient as ~60% of patients relapse within two years, indicating a need to identify novel targeted therapies to improve survival outcomes for HNC patients. Human papilloma virus (HPV) incidence is a major cause of head and neck squamous cell carcinoma (HNSCC) in addition to tobacco use. HPV- HNSCC patients are less responsive to frontline treatment than HPV+ HNSCC patients. However, HPV- and HPV+ HNSCC patients are treated similarly. The cell cycle serine-threonine kinase polo-like kinase 1 (Plk1) is known to be overexpressed in HNC. The Cancer Genome Atlas (TCGA) revealed that high expression of Plk1 correlates with worse survival in HNSCC patients (p<0.05). Yet, Plk1 is expressed at similar levels when comparing HPV- and HPV+ HNSCC patients. Therefore, in this study we sought to establish if Plk1 inhibition with onvansertib (currently in Phase I/II clinical trials) alone and in combination with radiation would inhibit HPV- and HPV+ HNSCC growth. We used two HPV+ (UMSCC47, UDSCC2), and two HPV- (HN5, Cal27) human HNSCC cell lines. First, we confirmed that Plk1 inhibition with onvansertib stalls HNSCC cells at the G2/M phase of the cell cycle (n=3). Then, we determined that HNSCC cell viability is reduced in a dose-dependent manner after Plk1 inhibition with onvansertib. Surprisingly, HPV- HNSCC cells exhibited a 2-fold decrease in cell viability as compared to HPV+ HNSCC cells (n=3). These findings were confirmed when assessing 3D spheroid growth of HNSCC cells. Plk1 inhibition with onvansertib (25nM) reduced HPV- HNSCC spheroid growth more than HPV+ (n=2). Combining Plk1 inhibition with radiation also reduced colony formation (n=3, p<0.0001) and increased G2/M stalling (n=3) compared to either single agent in HPV- HNSCC cells. Functionally, onvansertib induces cleaved PARP and pPlk1 expression in HNSCC cells. However, pPlk1 is induced to a higher degree in HPV+ HNSCC cells potentially indicating a positive feedforward loop leading to decreased sensitivity to Plk1 inhibition. In HPV- but not HPV+ HNSCC cells, Plk1 expression is also increased after radiation emphasizing Plk1 as an attractive target to mitigate radioresistance in HPV- HNSCCs (n=3). Our findings that HPV+ HNSCC cells are more resistant to Plk1 inhibition than HPV- HNSCC cells provides novel mechanistic insight into these disease subtypes. As HPV- HNSCC is typically more resistant to standard therapies, these results support a novel combinatorial approach using an already approved Plk1 inhibitor with radiation to improve HPV- HNSCC patient outcomes. Citation Format: Julianna Korns, Samuel Thompson, Trisha Wise-Draper, Vinita Takiar. Plk1 signaling as a therapeutic target for HPV- head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2832.

Kinesin Family Member C1 Overexpression Exerts Tumor-Promoting Properties in Head and Neck Squamous Cell Carcinoma via the Rac1/Wnt/β-catenin Pathway

Kinesin family member C1 (KIFC1) is a kinesin-14 motor protein, and its abnormal upregulation promotes the malignant behavior of cancer cells. N6-methyladenosine (m6A) RNA methylation is a common modification of eukaryotic messenger RNA and affects RNA expression. In this study, we explored how KIFC1 regulated head and neck squamous cell carcinoma (HNSCC) tumorigenesis and how m6A modification affected KIFC1 expression. A bioinformatics analysis was performed to screen for genes of interest, and in vitro and in vivo studies were carried out to investigate the function and mechanism of KIFC1 in HNSCC tissues. We observed that the expression of KIFC1 in HNSCC tissues was significantly higher than that in normal or adjacent normal tissues. Patients with cancer with higher KIFC1 expression have a lower tumor differentiation status. Demethylase alkB homolog 5, a cancer-promoting factor in HNSCC tissues, could interact with KIFC1 messenger RNA and posttranscriptionally activate KIFC1 through m6A modification. KIFC1 downregulation suppressed HNSCC cell growth and metastasis in vivo and in vitro. However, overexpression of KIFC1 promoted these malignant behaviors. We demonstrated that KIFC1 overexpression activated the oncogenic Wnt/β-catenin pathway. KIFC1 interacted with the small GTPase Ras-related C3 botulinum toxin substrate 1 (Rac1) at the protein level and increased its activity. The Rho GTPase Rac1 was indicated to be an upstream activator of the Wnt/β-catenin signaling pathway, and its Rac1 inhibitor, NSC-23766, treatment reversed the effects caused by KIFC1 overexpression. Those observations demonstrate that abnormal expression of KIFC1 may be regulated by demethylase alkB homolog 5 in an m6A-dependent manner and promote HNSCC progression via the Rac1/Wnt/β-catenin pathway.

Epigallocatechin Gallate (EGCG), an Active Phenolic Compound of Green Tea, Inhibits Tumor Growth of Head and Neck Cancer Cells by Targeting DNA Hypermethylation

Head and neck cancers are among the deadliest cancers, ranked sixth globally in rates of high mortality and poor patient prognoses. The prevalence of head and neck squamous cell carcinoma (HNSCC) is associated with smoking and excessive alcohol consumption. Despite several advances in diagnostic and interventional methods, the morbidity of subjects with HNSCC has remained unchanged over the last 30 years. Epigenetic alterations, such as DNA hypermethylation, are commonly associated with several cancers, including HNSCC. Thus, epigenetic changes are considered promising therapeutic targets for chemoprevention. Here, we investigated the effect of EGCG on DNA hypermethylation and the growth of HNSCC. First, we assessed the expression levels of global DNA methylation in HNSCC cells (FaDu and SCC-1) and observed enhanced methylation levels compared with normal human bronchial epithelial cells (NHBE). Treatment of EGCG to HNSCC cells significantly inhibited global DNA hypermethylation by up to 70-80% after 6 days. Inhibition of DNA hypermethylation in HNSCC cells was confirmed by the conversion of 5-methylcytosine (5-mc) into 5-hydroxy methylcytosine (5hmC). DNA methyltransferases regulate DNA methylation. Next, we checked the effect of EGCG on the expression levels of DNA methyltransferases (DNMTs) and DNMT activity. Treatment of EGCG to HNSCC cells significantly reduced DNMT activity to 60% in SCC-1 and 80% in FaDu cells. The protein levels of DNMT3a and DNMT3b were downregulated in both cell lines after EGCG treatment. EGCG treatment to HNSCC cells reactivated tumor suppressors and caused decreased cell proliferation. Our in vivo study demonstrated that administration of EGCG (0.5%, w/w) as a supplement within an AIN76A diet resulted in inhibition of tumor growth in FaDu xenografts in nude mice (80%; p < 0.01) compared with non-EGCG-treated controls. The growth inhibitory effect of dietary EGCG on the HNSCC xenograft tumors was associated with the inhibition of DNMTs and reactivation of silenced tumor suppressors. Together, our study provides evidence that EGCG acts as a DNA demethylating agent and can reactivate epigenetically silenced tumor suppressors to inhibit the growth of HNSCC cells.

Ferroportin depletes iron needed for cell cycle progression in head and neck squamous cell carcinoma.

Ferroportin (FPN), the only identified eukaryotic iron efflux channel, plays an important role in iron homeostasis and is downregulated in many cancers. To determine if iron related pathways are important for Head and Neck Squamous Cell Carcinoma (HNSCC) progression and proliferation, we utilize a model of FPN over-expression to simulate iron depletion and probe associated molecular pathways. The state of iron related proteins and ferroptosis sensitivity was assessed in a panel of metastatic HNSCC cell lines. Stable, inducible expression of FPN was confirmed in the metastatic HNSCC lines HN12 and JHU-022 as well as the non-transformed normal oral keratinocyte (NOK) cell line and the effect of FPN mediated iron depletion was assessed in these cell lines. HNSCC cells are sensitive to iron chelation and ferroptosis, but the non-transformed NOK cell line is not. We found that FPN expression inhibits HNSCC cell proliferation and colony formation but NOK cells are unaffected. Inhibition of cell proliferation is rescued by the addition of hepcidin. Decreases in proliferation are due to the disruption of iron homeostasis via loss of labile iron caused by elevated FPN levels. This in turn protects HNSCC cells from ferroptotic cell death. Expression of FPN induces DNA damage, activates p21, and reduces levels of cyclin proteins thereby inhibiting cell cycle progression of HNSCC cells, arresting cells in the S-phase. Induction of FPN severely inhibits Edu incorporation and increased β-galactosidase activity, indicating cells have entered senescence. Finally, in an oral orthotopic mouse xenograft model, FPN induction yields a significant decrease in tumor growth. Our results indicate that iron plays a role in HNSCC cell proliferation and growth and is important for cell cycle progression. Iron based interventional strategies such as ferroptosis or iron chelation may have potential therapeutic benefits in advanced HNSCC.

Role of LONP2 in head and neck squamous cell carcinoma

Lon Peptidase 2, Peroxisomal (LONP2) is a peptidase in peroxisomes that selectively degrades oxidatively damaged proteins in cells and is upregulated in several cancers. In this study, we found both the mRNA and protein level of LONP2 was upregulated in head and neck squamous cell carcinoma (HNSCC) samples. Ectopic overexpressed LONP2 enhanced HNSCC cell growth and migration. Nevertheless, LONP2 silencing suppressed tumor growth in vitro and in vivo. It was also indicated that knockdown of LONP2 also impaired the cell cycle progression and improved apoptosis rate of HNSCC cells. The results of RNA sequencing showed that plastin 3 (PLS3) was heavily downregulated after LONP2 silencing. PLS3 is an actin-bundling protein that functions as an oncogene in several cancers. Furthermore, knockdown of PLS3 inhibited the cell proliferation induced by LONP2 overexpression. In conclusion, we identified an oncogenic effect of LONP2 on cell proliferation and migration in HNSCC via positively regulating the expression of PLS3.

Hypoxia-Regulated lncRNA USP2-AS1 Drives Head and Neck Squamous Cell Carcinoma Progression.

The role of hypoxia-regulated long non-coding RNA (lncRNA) in the development of head and neck squamous cell carcinoma (HNSCC) remains to be elucidated. In the current study, we initially screened hypoxia-regulated lncRNA in HNSCC cells by RNA-seq, before focusing on the rarely annotated lncRNA USP2 antisense RNA 1 (USP2-AS1). We determined that USP2-AS1 is a direct target of HIF1α and is remarkably elevated in HNSCC compared with matched normal tissues. Patients with a higher level of USP2-AS1 suffered a poor prognosis. Next, loss- and gain-of-function assays revealed that USP2-AS1 promoted cell proliferation and invasion in vitro and in vivo. Mechanically, RNA pulldown and LC-MS/MS demonstrated that the E3 ligase DDB1- and CUL4-associated factor 13 (DCAF13) is one of the binding partners to USP2-AS1 in HNSCC cells. In addition, we assumed that USP2-AS1 regulates the activity of DCAF13 by targeting its substrate ATR. Moreover, the knockdown of DCAF13 restored the elevated cell proliferation and growth levels achieved by USP2-AS1 overexpression. Altogether, we found that lncRNA USP2-AS1 functions as a HIF1α-regulated oncogenic lncRNA and promotes HNSCC cell proliferation and growth by interacting and modulating the activity of DCAF13.

Abstract 2573: PI3K/AKT/mTOR pathway and CDK4/6 inhibitors efficiently inhibit cell growth of HPV-positive and HPV-negative head and neck squamous cell carcinoma in vitro

Abstract Introduction: Both HPV-positive and -negative head and neck squamous cell carcinoma (HNSCC) often show activation of the PI3K/AKT/mTOR pathway, due to, amongst others, PI3KCA mutations, PTEN loss, or receptor tyrosine kinase activation. In HPV-negative tumors, CDKN2A (p16) inactivation or CCND1 (cyclin D1) amplification frequently occurs resulting in sustained cyclin dependent kinase (CDK) 4/6 activation. The aim of our study was to investigate the efficacy of PI3K/AKT/mTOR pathway inhibitors (PI3Ki) (alpelisib, buparlisib and gedatolisib) and CDK4/6 inhibitors (CDKi) (palbociclib and ribociclib) in HPV-positive and -negative HNSCC cell lines. Methods: The efficacy of the inhibitors was assessed using MTT assays and changes in PI3K and Cyclin D1/CDK pathway protein expression were determined by Western blotting. Cell cycle analysis was performed with flow cytometry and apoptosis was assessed by Annexin-V staining. Changes in cell metabolism were assessed by Seahorse XF assays. Results: Both HPV-positive and -negative HNSCC cell lines were highly sensitive to the PI3Ki (Gedatolisib, IC50 5-30 nM &amp;gt; Buparlisib, IC50 0.6-3.6 µM &amp;gt; Alpelisib, IC50 3-23 µM). In general, PI3Ki decreased pathway activity, resulted in moderate cell cycle arrest and apoptosis, and decreased oxidative and glycolytic metabolism. CDKi were particularly effective in blocking HPV-negative cell line growth (Palbociclib, IC50 0.5-2 µM &amp;gt; Ribociclib, IC50 4-7 µM). CDK inhibition showed decreased pRb expression and G1 cell cycle arrest, whereas apoptosis was not induced. Conclusion: PI3Ki and CDKi efficiently inhibit their respective pathways and HNSCC cell growth in vitro, the latter only in HPV-negative cell lines. Whereas PI3Ki especially show an effect on oxidative and glycolytic metabolism, CDKi particularly lead to cell cycle arrest. Further research should elucidate whether these inhibitors may be effective therapeutic agents in HNSCC patients. Citation Format: Imke Demers, Femke Verhees, Dion Leegemaate, Robin Jacobs, Ann Hoeben, Frank Hoebers, Bernd Kremer, Ernst-Jan Speel. PI3K/AKT/mTOR pathway and CDK4/6 inhibitors efficiently inhibit cell growth of HPV-positive and HPV-negative head and neck squamous cell carcinoma in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2573.

ATAD3A mediates activation of RAS-independent mitochondrial ERK1/2 signaling, favoring head and neck cancer development

BackgroundTargeting mitochondrial oncoproteins presents a new concept in the development of effective cancer therapeutics. ATAD3A is a nuclear-encoded mitochondrial enzyme contributing to mitochondrial dynamics, cholesterol metabolism, and signal transduction. However, its impact and underlying regulatory mechanisms in cancers remain ill-defined.MethodsWe used head and neck squamous cell carcinoma (HNSCC) as a research platform and achieved gene depletion by lentiviral shRNA and CRISPR/Cas9. Molecular alterations were examined by RNA-sequencing, phospho-kinase profiling, Western blotting, RT-qPCR, immunohistochemistry, and immunoprecipitation. Cancer cell growth was assessed by MTT, colony formation, soft agar, and 3D cultures. The therapeutic efficacy in tumor development was evaluated in orthotopic tongue tumor NSG mice.ResultsATAD3A is highly expressed in HNSCC tissues and cell lines. Loss of ATAD3A expression suppresses HNSCC cell growth and elicits tumor regression in orthotopic tumor-bearing mice, whereas gain of ATAD3A expression produces the opposite effects. From a mechanistic perspective, the tumor suppression induced by the overexpression of the Walker A dead mutant of ATAD3A (K358) produces a potent dominant-negative effect due to defective ATP-binding. Moreover, ATAD3A binds to ERK1/2 in the mitochondria of HNSCC cells in the presence of VDAC1, and this interaction is essential for the activation of mitochondrial ERK1/2 signaling. Most importantly, the ATAD3A-ERK1/2 signaling axis drives HNSCC development in a RAS-independent fashion and, thus, tumor suppression is more effectively achieved when ATAD3A knockout is combined with RAS inhibitor treatment.ConclusionsThese findings highlight the novel function of ATAD3A in regulating mitochondrial ERK1/2 activation that favors HNSCC development. Combined targeting of ATAD3A and RAS signaling may potentiate anticancer activity for HNSCC therapeutics.

Phosphorylation of MICAL2 by ARG promotes head and neck cancer tumorigenesis by regulating skeletal rearrangement.

The actin cytoskeletal architecture provides the structural underpinnings for crucial cellular behaviors. In cancer cells, changes in the actin cytoskeleton may serve as prerequisites for proliferation, invasion, and metastatic dissemination. However, the underlying mechanisms remain largely unknown. Here, we show that MICAL2, which is increased in head and neck squamous cell carcinoma (HNSCC) and inversely associated with patient survival, promotes HNSCC growth, invasion, and migration. MICAL2 serves as a flavoprotein monooxygenase and directly induces actin filament depolymerization by specifically oxidizing the methionine 44 and 47 residues of F-actin. The kinase ARG interacts with MICAL2 and augments MICAL2-mediated actin disassembly. Direct phosphorylation assay and mass spectrometry confirmed that ARG phosphorylates MICAL2 at Tyr445, Tyr463, and Tyr488. Substitution of the Tyr445 or Tyr463 residue of purified recombinant MICAL2-redox with phenylalanine (generating a non-phosphorylatable mutant) abolishes the enhanced MICAL2-mediated F-actin disassembly induced by ARG. Consistently, ectopic expression of non-phosphorylatable MICAL2 mutants (MICAL2Y445F and MICAL2Y463F, not MICAL2Y488F) failed to ameliorate HNSCC cell growth, whereas expression of wild-type MICAL2 or MICAL2Y488F rescued the impaired proliferation induced by MICAL2 knockdown. Moreover, CCG-1423, an inhibitor of MICAL2, was shown to inhibit HNSCC cell proliferation, invasion, and migration. Taken together, our findings indicate that phosphorylation of MICAL2 at Tyr445 and Tyr463 by ARG mediates F-actin disassembly and promotes HNSCC progression.

FAM83A promotes proliferation and metastasis via Wnt/\u03b2-catenin signaling in head neck squamous cell carcinoma

This research aimed to investigate the expression and function of FAM83A in the proliferation and metastasis in head and neck squamous cell carcinoma (HNSCC). FAM83A mRNA and protein expressions in HNSCC were detected in primary HNSCC samples and cell lines. The associations between FAM83A expression and clinicopathologic variables were evaluated through tissue microarrays. Besides, FAM83A knockdown and overexpression cell lines were constructed to assess cell growth and metastasis in vitro and the relationship between FAM83A and epithelial-mesenchymal transition (EMT). Furthermore, two models of xenograft tumors in nude mice were used to assess the tumorigenicity and metastasis ability of FAM83A in vivo. In the present study, overexpression of FAM83A in HNSCC samples was significantly associated with tumor size, lymph node status and clinical tumor stages. Mechanically, FAM83A could promote HNSCC cell growth and metastasis by inducing EMT via activating Wnt/β-catenin signaling pathway. Rescue experiment demonstrated the inhibition of β-catenin could counteract the function of FAM83A. Also, the FAM83A knockdown could suppress tumor growth and distant metastasis in the xenograft animal models of HNSCC. In conclusion, this study identifies FAM83A as an oncogene of HNSCC. This study provides new insights into the molecular pathways that contribute to EMT in HNSCC. We revealed a previously unknown FAM83A-Wnt–β-catenin signaling axis involved in the EMT of HNSCC. There may be a potential bi-directional signaling loop between FAM83A and Wnt/β-catenin signaling pathway in HNSCC.

NR5A2 Is One of 12 Transcription Factors Predicting Prognosis in HNSCC and Regulates Cancer Cell Proliferation in a p53-Dependent Manner.

Head and neck squamous cell carcinoma (HNSCC) rank seventh among the most common type of malignant tumor worldwide. Various evidences suggest that transcriptional factors (TFs) play a critical role in modulating cancer progression. However, the prognostic value of TFs in HNSCC remains unclear. Here, we identified a risk model based on a 12-TF signature to predict recurrence-free survival (RFS) in patients with HNSCC. We further analyzed the ability of the 12-TF to predict the disease-free survival time and overall survival time in HNSCC, and found that only NR5A2 down-regulation was strongly associated with shortened overall survival and disease-free survival time in HNSCC. Moreover, we systemically studied the role of NR5A2 in HNSCC and found that NR5A2 regulated HNSCC cell growth in a TP53 status-dependent manner. In p53 proficient cells, NR5A2 knockdown increased the expression of TP53 and activated the p53 pathway to enhance cancer cells proliferation. In contrast, NR5A2 silencing suppressed the growth of HNSCC cells with p53 loss/deletion by inhibiting the glycolysis process. Therefore, our results suggested that NR5A2 may serve as a promising therapeutic target in HNSCC harboring loss-of-function TP53 mutations.

PLAU1 Facilitated Proliferation, Invasion, and Metastasis via Interaction With MMP1 in Head and Neck Squamous Carcinoma.

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignant neoplasm; it is associated with high morbidity and mortality. Thus, understanding the molecular mechanisms underlying its initiation and progression is critical for establishing the most appropriate treatment strategies. We found that urokinase-type plasminogen activator (PLAU1) was upregulated and associated with poor prognosis in HNSCC. Silencing of PLAU1 inhibited the proliferation, colony-formation, migration, and invasion abilities of HNSCC cells in vitro and reduced the expression of matrix metalloproteinase 1 (MMP1), whereas PLAU1 overexpression significantly enhanced the growth, the colony-formation, migration, and invasion abilities, and the xenograft tumor growth of HNSCC cells in vivo and increased the expression of MMP1. The Co-IP assay verified that PLAU1 interacted with MMP1. A positive correlation between PLAU1 and MMP1 expression was observed in HNSCC samples. si-RNAs against MMP1 reversed the aggressive effects of PLAU1 overexpression in HNSCC. Taken together, our data revealed that PLAU1 facilitated HNSCC cell proliferation, invasion, and metastasis via interaction with MMP1.