Head And Neck Cancer Cell Research Articles

Antioxidant, cytotoxic, anti-migratory, and pro-apoptotic effects of Bolanthus turcicus extracts on head and neck cancer cells.

Investigation of various plant extracts using in-vitro/in-vivo assays has emerged as a promising avenue for identifying potential pharmacophores that can be developed into therapeutic drugs. This study aims to assess the bioactive compounds and antioxidant capacity of the Bolanthus turcicus (B. turcicus) and to investigate the effects on head and neck cancer (HNC) cell lines. Methanol (MeOH), ethyl acetate (EA) and aqueous (Aq) extracts were prepared from B. turcicus, and the amount of total phenolic content (TPC) and total flavonoid content (TFC) in the extracts were analyzed by the Folin-Ciocalteu and Aluminum chloride method, respectively. In addition, the total antioxidant capacity and iron reducing potential of B. turcicus extracts were determined by the Phosphomolybdenum and Ferric ion reducing antioxidant power (FRAP) method. The effect of B. turcicus on HEp-2, SCC-90, SCC-9, FaDu HNC cell viability, motility, and cell-nuclear morphology was evaluated by MTT, scratch-wound healing assay, and Pllalloidin-DAPI staining, respectively. The effect of B. turcicus on the expression of CASP-3, BAX, and BCL-2 genes at the mRNA, protein, and intracellular level was evaluated by quantitative PCR (qPCR), western blot, and immunofluorescence staining. Moreover, Annexin V-FITC/PI, was used in flow cytometry to investigate the effect of B. turcicus on apoptosis. The MeOH extract exhibited the highest phenolic content, flavonoid content and antioxidant activity (p < 0.05 for all). HNC cells treated with extracts indicated delayed wound healing and decreased motility (p < 0.05 for all). Analysis of annexin V-PI staining indicated that the B. turcicus extracts induced apoptosis but not viability and necrosis in the HNC cell (p < 0.05 for all). Moreover, qPCR data regarding the apoptotic mechanism showed that the extracts could induce apoptosis by upregulation of pro-apoptotic CASP-3 and BAX genes and downregulation of anti-apoptotic BCL-2 gene (p < 0.05 for all). The expression of protein and intracellular levels of CASP-3 and BAX were increased, while the BCL-2 was decreased in cells treated with the extracts (p < 0.05 for all). In addition, diffuse pycnosis and DNA condensation in HNC cell nuclei, confirming apoptotic cell death (p < 0.05 for all). This study data indicated that B. turcicus extracts have antioxidant, cytotoxic, anti-migratory and pro-apoptotic activity. In conclusion, it has been shown that B. turcicus can be used as a potential therapeutic agent against HNC.

Pterostilbene suppresses head and neck cancer cell proliferation via induction of apoptosis.

Head and neck cancer (HNC) is one of the most prevalent causes of death worldwide, and so discovering anticancer agents for its treatment is very important. Pterostilbene (PS) is a trans-stilbene reported to be beneficial in managing various cancers. The objective of the study was to evaluate the cytotoxic, antiproliferative, proapoptotic, and antimigrative effect of PS on HEp-2, SCC-90, SCC-9, FaDu, and Detroit-551 cell lines. MTT and live/dead assays were employed to assess cell viability, while a cell migration test was performed to evaluate wound healing capacity. The mRNA, protein, and intracellular expression levels of CASP-3, BAX, and BCL-2 genes were evaluated by real-time PCR, western blotting, and immunofluorescence staining. Annexin V-PI staining was conducted to assess the amounts of viable, apoptotic, and necrotic cells. The results revealed that PS displayed cytotoxic, antiproliferative activity in a dose-dependent manner in HNC cells by upregulating CASP-3 and BCL-2 while downregulating BCL-2 in the apoptotic pathway. The proapoptotic properties were confirmed by the annexin-V-IP results. Moreover, PS displayed a significant suppressive efficacy on the migration capacity of HNC cells. The present study provides proof that PS has the prospective to be improved as an attractive anticancer agent against HNC following advanced studies.

Cold atmospheric plasma activated media selectively affects human head and neck cancer cell lines.

Cold atmospheric plasma (CAP) is a novel approach for cancer treatment. It can be used to treat liquids-plasma-activated media (PAM)-which are then transferred to the target as an exogenous source of reactive oxygen and nitrogen species (RONS). The present study aimed at chemically characterizing different PAM and assessing their invitro selectivity against head and neck cancer cells (HNC). PAM were obtained by exposing 2 and 5 mL of cell culture medium to CAP for 5, 10 and 20 min at a 6 mm working distance. Anions kinetics was evaluated by ion chromatography. Cell proliferation inhibition, apoptosis occurrence, and cell cycle modifications were assessed by MTS and flow cytometry, on human epidermal keratinocyte (HaCaT) and HNC cell lines HSC3, HSC4 and A253. The 2 mL conditions showed a significant reduction in cell proliferation whereas for the 5 mL the effect was milder, but the time-dependence was more evident. HaCaT were unaffected by the 5 mL PAM, indicating a selectivity for cancer cells. The media chemical composition modified by CAP exposure influenced cell proliferation by modulating cell cycle and inducing apoptosis in cancer cells, without affecting normal cells.

A biocompatible nanoformulation of curcumin analogue and curd exosomes targeting EphA2 signalling cascade in head and neck cancer

BackgroundMajor therapeutic developments have been made in the prevention of head and neck cancer (HNC), and crucial measures have been implemented for the survival of patients. The advent of cancer nano-theranostic as an effective approach targets cancer by allowing drug aggregation at the tumour site, its proper bioaccessibility, and tumour cell death. Curd exosomes are the cellular interactive nanovesicles, considered a convenient conveyance medium for cargoes still unexplored. Curcumin analogue alanine is primarily recognised for its superior radical scavenging activity and anti-mutagen properties compared with curcumin.MethodsThe current study focussed on the isolation and characterisation of curd exosomes, followed by their interaction with cancer cells to deliver their content conveniently. Herein, we developed a nanoformulation of curd exosomes loaded with curcumin alanine to determine its bioaccessibility and anti-proliferative effect compared with curcumin alanine free drug. In addition, the influence of curcumin alanine and its nanoformulation on cell morphology, nucleus structures, colony formation potential, and tumour cell death was observed. The expression of EphA2 and its associated molecules was determined using western blot and PCR to explore the mechanism at the cellular level.ResultsThe recent investigation revealed the encapsulation of curcumin analogue alanine in curd exosomes enhanced the bioaccessibility in contrast with curcumin alanine. Then, we focussed on the curcumin alanine effect on HNC cells to monitor morphological alterations, a reduction in cell multiplication, and triggering apoptosis. Particularly, we found considerable suppression of EphA2 influencing mitochondrial dynamics with the strengthening of mitochondrial fusion MFN1 and MFN2, whereas fission-associated protein DRP1 was down-regulated by the treatment of curcumin alanine nanoformulation. Furthermore, curcumin alanine nanoformulation activates the apoptotic marker caspase-7 and suppresses the anti-apoptotic marker Bcl-xL.ConclusionHence, these findings have drawn attention to curd exosomes loaded curcumin alanine nanoformulation impairing cell multiplication and mitochondrial fission, leading to apoptotic cell death, as one of the effective approaches for the treatment of HNC.Graphical

An epidermal growth factor receptor‐targeting immunotoxin based on IgG shows potent antitumor activity against head and neck cancer

AbstractThe epidermal growth factor receptor (EGFR) is an important target for cancer therapies. Many head and neck cancer (HNC) cells have been reported to overexpress EGFR; therefore, anti‐EGFR therapies have been attempted in patients with HNC. However, its clinical efficacy is limited owing to the development of drug resistance. In this study, we developed an EGFR‐targeting immunotoxin consisting of a clinically proven anti‐EGFR IgG (cetuximab; CTX) and a toxin fragment (LR‐LO10) derived from Pseudomonas exotoxin A (PE) using a novel site‐specific conjugation technology (peptide‐directed photo‐crosslinking reaction), as an alternative option. The immunotoxin (CTX‐LR‐LO10) showed specific binding to EGFR and properties of a typical IgG, such as stability, interactions with receptors of immune cells, and pharmacokinetics, and inhibited protein synthesis via modification of elongation factor‐2. Treatment of EGFR‐positive HNC cells with the immunotoxin resulted in apoptotic cell death and the inhibition of cell migration and invasion. The efficacy of CTX‐LR‐LO10 was evaluated in xenograft mouse models, and the immunotoxin exhibited much stronger tumor suppression than CTX or LR‐LO10. Transcriptome analyses revealed that the immunotoxins elicited immune responses and altered the expression of genes related to its mechanisms of action. These results support the notion that CTX‐LR‐LO10 may serve as a new therapeutic agent targeting EGFR‐positive cancers.

Oxygen-releasing nanodroplets relieve intratumoral hypoxia in head and neck cancer spheroids.

Hypoxia in solid tumors, including head and neck cancer (HNC), contributes to treatment resistance, aggressive phenotypes, and poor clinical outcomes. Perfluorocarbon nanodroplets have emerged as promising oxygen carriers to alleviate tumor hypoxia. However, a thorough characterization of the hypoxia alleviation effects in terms of sustenance of oxygenated environments have not been thoroughly studied. In this study, we developed and characterized perfluoropentane nanodroplets (PFP NDs) for co-delivery of oxygen and the photoactivatable drug or photosensitizer benzoporphyrin derivative (BPD) to hypoxic HNC spheroids. The PFP NDs exhibited excellent stability, efficient oxygen loading/release, and biocompatibility. Using 3D multicellular tumor spheroids of FaDu and SCC9 HNC cells, we demonstrated the ability of oxygenated PFP NDs to penetrate the hypoxic core and alleviate hypoxia, as evidenced by reduced fluorescence of a hypoxia-sensing reagent and downregulation of hypoxia-inducible factors HIF-1α and HIF-2α. BPD-loaded PFP NDs successfully delivered the photosensitizer into the spheroid core in a time-dependent manner. These findings highlight the potential of PFP NDs as a co-delivery platform to overcome hypoxia-mediated treatment resistance and improve therapy outcomes in HNC.

LncRNA PART1 promotes malignant biological behaviours associated with head and neck cancer cells via synergistic action with FUT6

The aim of this study was to determine the role of lncRNA PART1 and downstream FUT6 in tumorigenesis and progression of head and neck cancer (HNC). Bioinformatics analysis and qRT-PCR revealed that lncRNA PART1 was expressed at low levels in HNC patients. The proliferation, apoptosis, migration and flow cytometry results showed that low expression of lncRNA PART1 inhibited apoptosis and promoted HNC cell migration and proliferation. In addition, animal experiments have also shown that low expression of lncRNA PART1 can promote tumor growth. LncRNA PART1 overexpression promoted apoptosis and inhibited HNC cell migration and proliferation. Through bioinformatics analysis, FUT6 was found to be expressed at low levels in HNC and to be correlated with patient survival. Immunohistochemical and qRT-PCR results revealed that FUT6 was underexpressed in tumour tissues and HNC cells. Cell and animal experiments showed that overexpression of FUT6 could inhibit tumour proliferation and migration. Bioinformatics analysis revealed that lncRNA PART1 was positively correlated with FUT6. By qRT-PCR and western blot, we observed that after knockdown of lncRNA PART1, both the mRNA and protein expression levels of FUT6 were reduced. The above results indicated that lncRNA PART1 and FUT6 play an important role in HNC, and that lncRNA PART1 affected the development of tumor by downstream FUT6.

PLAU promotes cell proliferation and migration of head and neck cancer via STAT3 signaling pathway

It was reported that within the head and neck cancer (HNC) cell line CAL21 the epithelial-mesenchymal transition (EMT) and cell proliferation were promoted by Urokinase-Type Plasminogen Activator (PLAU) proteinase through TNFRSF12A. Additionally, in this paper HNC cell lines refer to Fadu and Tu686. A novel PLAU-STAT3 axis was found to be involved in HNC cell line proliferation and metastasis. PLAU expression in HNC samples was upregulated, besides, the elevated expression of PLAU was linked to the lower overall survival (OS) and disease-free survival (DFS). Ectopic PLAU expression promoted cell proliferation and migration, while PLAU knockdown exhibited opposite results. RNA-seq data identified the JAK-STAT signaling pathway, confirmed by western blotting. A recovery assay using S3I-201, a selective inhibitor of signal transducer and activator of transcription 3 (STAT3), indicated that PLAU promoted HNC cell line progression via STAT3 signaling in vitro. The oncogenic role of PLAU in HNC tumor growth in vivo was confirmed using xenograft models. In summary, we identified the tumorigenic PLAU function in the HNC progress. PLAU may represent a potential prognostic biomarker of HNC and the PLAU-STAT3 pathway might be considered a therapeutic target of HNC.

IP3R1 dysregulation via mir-200c-3p/SSFA2 axis contributes to taxol resistance in head and neck cancer

Head and neck cancer (HNC) is the sixth most common malignancy worldwide. Although current modalities offer a wide variety of therapy choices, head and neck carcinoma has poor prognosis due to its diagnosis at later stages and development of resistance to current therapeutic tools. In the current study, we aimed at exploring the roles of miR-200c-3p during head and neck carcinogenesis and acquisition of taxol resistance. We analyzed miR-200c-3p levels in HNC clinical samples and cell lines using quantitative real-time polymerase chain reaction and evaluated the effects of differential miR-200c-3p expression on cancer-related cellular phenotypes using in-vitro tools. We identified and characterized a direct target of miR-200c-3p using in-silico tools, luciferase and various in-vitro assays. We investigated potential involvement of miR-200c-3p/SSFA2 axis in taxol resistance in-vitro. We found miR-200c-3p expression as significantly downregulated in both HNC tissues and cells compared to corresponding controls. Ectopic miR-200c-3p expression in HNC cells significantly inhibited cancer-related phenotypes such as viability, clonogenicity, migration, and invasion. We, then, identified SSFA2 as a direct target of miR-200c-3p and demonstrated that overexpression of SSFA2 induced malignant phenotypes in HNC cells. Furthermore, we found reduced miR-200c-3p expression in parallel with overexpression of SSFA2 in taxol resistant HNC cells compared to parental sensitive cells. Both involved in intracellular cytoskeleton remodeling, we found that SSFA2 works collaboratively with IP3R1 to modulate resistance to taxol in HNC cells. When considered collectively, our results showed that miR-200c-3p acts as a tumor suppressor microRNA and targets SSFA2/IP3R1 axis to sensitize HNC cells to taxol.

Matricellular proteins: Potential biomarkers in head and neck cancer.

The extracellular matrix (ECM) is a complex network of diverse multidomain macromolecules, including collagen, proteoglycans, and fibronectin, that significantly contribute to the mechanical properties of tissues. Matricellular proteins (MCPs), as a family of non-structural proteins, play a crucial role in regulating various ECM functions. They exert their biological effects by interacting with matrix proteins, cell surface receptors, cytokines, and proteases. These interactions govern essential cellular processes such as differentiation, proliferation, adhesion, migration as well as multiple signal transduction pathways. Consequently, MCPs are pivotal in maintaining tissue homeostasis while orchestrating intricate molecular mechanisms within the ECM framework. The expression level of MCPs in adult steady-state tissues is significantly low; however, under pathological conditions such as inflammation and cancer, there is a substantial increase in their expression. In recent years, an increasing number of studies have focused on elucidating the role and significance of MCPs in the development and progression of head and neck cancer (HNC). During HNC progression, there is a remarkable upregulation in MCP expression. Through their distinctive structure and function, they actively promote tumor growth, invasion, epithelial-mesenchymal transition, and lymphatic metastasis of HNC cells. Moreover, by binding to integrins and modulating various signaling pathways, they effectively execute their biological functions. Furthermore, MCPs also hold potential as prognostic indicators. Although the star proteins of various MCPs have been extensively investigated, there remains a plethora of MCP family members that necessitate further scrutiny. This article comprehensively examines the functionalities of each MCP and highlights the research advancements in the context of HNC, with an aim to identify novel biomarkers for HNC and propose promising avenues for future investigations.

Abstract 1241: Enhancing NK cell therapy for head and neck cancer within the solid tumor microenvironment using a B7H3-targeting tri-specific killer engager (TriKE)

Abstract With an annual incidence rate exceeding 660,000 cases, and a death toll surpassing 325,000 per year, head and neck cancer (HNC) ranks as the seventh most common cancer in the world. Surgery, radiation and chemotherapy are used to treat HNC patients with modest and variable clinical success. However, these treatments prove less effective for human papillomavirus negative (HPV-) HNC patients, a subset of HNC patients with markedly worse prognosis. While significant advancements have been made in cancer immunotherapy over the past decade, its success also remains elusive for HNC due to factors such as the hypoxic solid tumor microenvironment (TME). To address the critical need for an improved therapeutic intervention, we leveraged the ability of natural killer (NK) cells in killing cancer cells without prior sensitization by developing a novel tri-specific killer engager (TriKE) that can direct NK cell killing of tumor within the hypoxic solid TME. The TriKE is composed of three domains: a humanized nanobody arm binding the activating receptor CD16 on NK cells, an interleukin (IL)-15 moiety that can drive expansion of NK cells, and a nanobody arm binding B7H3, a protein which high expression can be negatively correlated with overall survival of HPV- HNC patients. B7H3 is a prime target candidate because it is highly expressed on HPV- HNC cells, but minimally expressed on healthy tissues. In vitro testing using HPV- HNC patient blood samples revealed that B7H3 TriKE enhances activation (measured by NK cell degranulation and interferon-gamma production) and expansion of NK cells from these patients at levels equivalent to those observed in healthy controls. Furthermore, B7H3 TriKE is efficacious in its ability to drive high NK cell cytotoxicity in both acute (&amp;lt;48-hours) and prolonged (7-days) hypoxic (1% oxygen) models of HNC. Under acute hypoxia, B7H3 TriKE induces significantly more killing of targets by NK cells compared to IL-15 treatment, where NK cell cytotoxicity is impaired. In addition, B7H3 TriKE can boost the killing efficacy of NK cells exposed to prolonged hypoxia, surpassing limitations seen with IL-15 treatment. These findings strongly suggest that the B7H3 TriKE can bypass hypoxic suppression of NK effector functions in the solid TME. In vivo studies using immunocompromised mice engrafted with HPV- HNC cells revealed that B7H3 TriKE treatment significantly extends the survival of mice, compared to IL-15 treatment. Moreover, NK cells persisted in the blood of B7H3 TriKE-treated mice 28 days post-NK cell injection, highlighting the promising clinical translation of this immunotherapy. More in-depth characterization of NK cells from HPV- HNC patients are underway but altogether, these robust pre-clinical data present a novel avenue for the management of HNC for these patients. We plan to translate results from these studies to clinical trials in fall 2024. Citation Format: Melissa Khaw, Nicholas A. Zorko, Carly Selleck, Laura Bendzick, Zachary Davis, Peter Hinderlie, Madison Shackelford, Ann Lu, James Lim, Naomi Fujioka, Margaret MacMillan, John Wagner, Martin Felices, Jeffrey S. Miller. Enhancing NK cell therapy for head and neck cancer within the solid tumor microenvironment using a B7H3-targeting tri-specific killer engager (TriKE) [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 1241.

Abstract 4617: Fisetin, a multi-kinase inhibitor enhances chemotherapeutic sensitivity in head and neck cancer

Abstract Background: The limitations of chemotherapeutic applications are often imposed by dose-related toxicity and the emergence of therapeutic resistance. Fisetin, a naturally occurring flavonoid, has demonstrated anticancer properties in various cancer types. Despite its proven effectiveness against cancer, the molecular target of fisetin remains unknown. Methods: Our study focused on understanding how fisetin and chemotherapy work together to inhibit the growth and survival of human HNC. We conducted in silico, in vitro and in vivo investigations. We employed target prediction, kinase profiling, transcriptome analysis and tumor xenograft to identify the chemosensitivity efficacy and mechanism of fisetin. Results: In-silico target prediction suggested that fisetin might target multiple kinases. Based on this lead, we have screened fisetin for different kinase inhibition activities and found that it inhibits multiple CDKs including CDK1, 2, 4, 5 and 6 at nanomolar concentration. To test its cellular activity, we have selected the head and neck cancer (HNC) model and found that fisetin treatment strongly inhibited cell proliferation and arrested the HNC cells in G1 phase followed by apoptotic cell death. In tumor xenograft experiment, we found that oral fisetin treatment inhibited the FaDu and SAS tumor growth in the athymic mouse model. Transcriptome analysis on FaDu and SAS cell lines indicated that fisetin treatment significantly modulates pathways associated with cell cycle progression and regulation. These pathways include cellular assembly, DNA replication, cell death, and cell morphology. Pretreatment of HNC cells with fisetin improved the effectiveness of chemotherapy drugs including cisplatin, 5-fluorouracil, and docetaxel. Consistent with this, fisetin pre-treated cells showed elevated levels of cellular and mitochondrial ROS followed by the activation of caspases and apoptosis induction when compared with that in control cells after cisplatin, 5-FU, or docetaxel treatment. Conclusion: These results imply that fisetin has the potential to be utilized as a multi-kinase inhibitor in cancer cells. The study revealed that fisetin has a strong potential for increasing the sensitivity of cancer cells to chemotherapy. Citation Format: Dhanir Tailor, Deepali Mishra, Sanjay V. Malhotra, Rana P. Singh. Fisetin, a multi-kinase inhibitor enhances chemotherapeutic sensitivity in head and neck cancer [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 4617.

Abstract 3880: LYTAC targeting galectin-1 to enhance radioimmunotherapy of cancers in the upper aerodigestive tract

Abstract Non-small cell lung cancer (NSCLC) and head and neck cancer (HNC), ranking respectively as a leading cause of cancer-related death and the sixth most common cancer worldwide. Despite treatment advancements, there's a pressing need for more effective strategies to improve survival and quality of life for NSCLC and HNC patients. Carolyn Bertozzi group recently reported in Nature the groundbreaking protein degraders named lysosome-targeted chimeras (LYTACs), which have bispecific binding affinity that drives cell-surface endocytic receptors to drag membrane or extracellular oncogenic proteins to lysosomes for degradation. They have successfully targeted critical oncoproteins such as epidermal growth factor receptor (EGFR) and more. However, current degradation demonstration was limited to in vitro cancer cells, LYTACs' impact on immune cell modulation and their therapeutic potentials in preclinical animal models remain unknown and require extensive evaluation before venturing to clinical trials.Our group and others have identified galectin-1 (Gal-1) as a multifaceted immunosuppressive biomarker overexpressed in NSCLC and HNC. By interacting with glycosylated receptors (e.g. CD45) on immune cells, it results in apoptosis of cytotoxic T cells, expansion of regulatory T cells, and intratumoral recruitment of myeloid-derived suppressor cells. Despite promising as an immune checkpoint target, effective anti-Gal-1 therapies are currently absent in clinical trials.Through histopathological analyses, we have confirmed substantial LYTAC receptor (cation-independent mannose-6-phosphate receptor, CI-M6PR) expression in ~200 HNC and ~400 NSCLC patient samples. Collaborating with Bertozzi group, we have developed the first Gal-1 targeting LYTAC named G-M6Pn which triggers significant target protein degradation in various human HNC and NSCLC cell lines. Such efficient Gal-1 degradation leads to significant immunosuppression reversal by stimulating CD8+ T cell and natural killer (NK) cell activation while dampening regulatory T cell (Treg) activity in both cell experiments and humanized mouse tumor models, resulting in excellent tumor/metastases control and survival improvement on both NSCLC and HNC models. When synergized with stereotactic ablative radiotherapy, the antitumor immune responses are further amplified and G-M6Pn also mediates ‘abscopal effect’ inhibiting non-irradiated tumors. This study thus contributes to expediting clinical translation of LYTACs as novel immune checkpoint degraders to improve personalized radio-immunotherapy of cancer. Citation Format: Yuyan Jiang, Green Ahn, Mobeen Rahman, Hongbin Cao, Carolyn Bertozzi, Qunh Le. LYTAC targeting galectin-1 to enhance radioimmunotherapy of cancers in the upper aerodigestive tract [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 3880.

Subcellular localization of PD-L1 and cell-cycle-dependent expression of nuclear PD-L1 variants: implications for head and neck cancer cell functions and therapeutic efficacy.

The programmed cell death 1 ligand 1 (PD-L1)/programmed cell death protein 1 (PD-1) axis is primarily associated with immunosuppression in cytotoxic T lymphocytes (CTLs). However, mounting evidence is supporting the thesis that PD-L1 not only functions as a ligand but mediates additional cellular functions in tumor cells. Moreover, it has been demonstrated that PD-L1 is not exclusively localized at the cellular membrane. Subcellular fractionation revealed the presence of PD-L1 in various cellular compartments of six well-characterized head and neck cancer (HNC) cell lines, including the nucleus. Via Western blotting, we detected PD-L1 in its well-known glycosylated/deglycosylated state at 40-55 kDa. In addition, we detected previously unknown PD-L1 variants with a molecular weight at approximately 70 and > 150 kDa exclusively in nuclear protein fractions. These in vitro findings were confirmed with primary tumor samples from head and neck squamous cell carcinoma (HNSCC) patients. Furthermore, we demonstrated that nuclear PD-L1 variant expression is cell-cycle-dependent. Immunofluorescence staining of PD-L1 in different cell cycle phases of synchronized HNC cells supported these observations. Mechanisms of nuclear PD-L1 trafficking remain less understood; however, proximity ligation assays showed a cell-cycle-dependent interaction of the cytoskeletal protein vimentin with PD-L1, whereas vimentin could serve as a potential shuttle for nuclear PD-L1 transportation. Mass spectrometry after PD-L1 co-immunoprecipitation, followed by gene ontology analysis, indicated interaction of nuclear PD-L1 with proteins involved in DNA remodeling and messenger RNA (mRNA) splicing. Our results in HNC cells suggest a highly complex regulation of PD-L1 and multiple tumor cell-intrinsic functions, independent of immune regulation. These observations bear significant implications for the therapeutic efficacy of immune checkpoint inhibition.

MiR-630 Promotes Radioresistance by Induction of Anti-Apoptotic Effect via Nrf2-GPX2 Molecular Axis in Head-Neck Cancer.

Head and neck cancer (HNC) ranks among the top ten prevalent cancers worldwide. Radiotherapy stands as a pivotal treatment component for HNC; however, radioresistance in cancerous cells often leads to local recurrence, becoming a substantial factor in treatment failure. MicroRNAs (miRNAs) are compact, non-coding RNAs that regulate gene expression by targeting mRNAs to inhibit protein translation. Although several studies have indicated that the dysregulation of miRNAs is intricately linked with malignant transformation, understanding this molecular family's role in radioresistance remains limited. This study determined the role of miR-630 in regulating radiosensitivity in HNC. We discovered that miR-630 functions as an oncomiR, marked by its overexpression in HNC patients, correlating with a poorer prognosis. We further delineated the malignant function of miR-630 in HNC cells. While it had a minimal impact on cell growth, the miR-630 contributed to radioresistance in HNC cells. This result was supported by decreased cellular apoptosis and caspase enzyme activities. Moreover, miR-630 overexpression mitigated irradiation-induced DNA damage, evidenced by the reduced levels of the γ-H2AX histone protein, a marker for double-strand DNA breaks. Mechanistically, the overexpression of miR-630 decreased the cellular ROS levels and initiated Nrf2 transcriptional activity, resulting in the upregulation of the antioxidant enzyme GPX2. Thus, this study elucidates that miR-630 augments radioresistance by inducing an anti-apoptotic effect via the Nrf2-GPX2 molecular axis in HNC. The modulation of miR-630 may serve as a novel radiosensitizing target for HNC.

Cold atmospheric plasma sensitizes head and neck cancer to chemotherapy and immune checkpoint blockade therapy

Head and neck cancer (HNC) is the seventh most prevalent cancer globally, often characterized by chemo-resistance and immunosuppression, which significantly hampers treatment efficacy. Cold atmospheric plasma (CAP) has recently emerged as a promising adjuvant oncotherapy with substantial potential and advantages. In this study, Piezobrush® PZ2, a handheld CAP unit based on the piezoelectric direct discharge technology, was used to generate and deliver non-thermal plasma. We aimed to investigate the effects of CAPPZ2 on various types of HNC cells and elucidate the underlying mechanisms. In addition, we endeavored to examine the efficacy of combining CAPPZ2 with chemotherapy drugs (i.e., cisplatin) or immune checkpoint blockade (ICB, i.e., PD1 antibody) in HNC treatment. Firstly, the results demonstrated that CAPPZ2 exerted anti-neoplastic functions through inhibiting cell proliferation, migration and invasion, and promoting apoptosis and autophagy. Secondly, using transcriptomic sequencing, Western blotting, and quantitative real-time PCR, the mechanisms underlying CAPPZ2 treatment in vitro was presumed to be a multitargeted blockade of major cancer survival pathways, such as redox balance, glycolysis, and PI3K/AKT/mTOR/HIF-1α signaling. Lastly, combinatorial thearpy containing CAPPZ2 and cisplatin or PD-1 antibody significantly suppressed tumor growth and prolonged recipient survival in vivo. Collectively, the synergistic effects of CAPPZ2 and cisplatin or PD-1 antibody could serve as a promising solution to enhance head and neck tumor elimination.

C-MYC-dependent transcriptional inhibition of autophagy is implicated in cisplatin sensitivity in HPV-positive head and neck cancer

Autophagy is important for the removal, degradation and recycling of damaged organelles, proteins, and lipids through the degradative action of lysosomes. In addition to its catabolic function, autophagy is important in cancer and viral-mediated tumorigenesis, including Human Papillomavirus (HPV) positive cancers. HPV infection is a major risk factor in a subset of head and neck cancer (HNC), for which no targeted therapies are currently available. Herein, we assessed autophagy function in HPV-positive HNC. We showed that HPV-positive HNC cells presented a transcriptional and functional impairment of the autophagic process compared to HPV-negative cells, which were reactivated by knocking down HPV E6/E7 oncoproteins, the drivers of cellular transformation. We found that the oncoprotein c-MYC was stabilized and triggered in HPV-positive cell lines. This resulted in the reduced binding of the MiT/TFE transcription factors to their autophagy targets due to c-MYC competition. Thus, the knock-down of c-MYC induced the upregulation of autophagic and lysosomal genes in HPV-positive HNC cells, as well as the increase of autophagic markers at the protein level. Moreover, HPV oncoprotein E7 upregulated the expression of the phosphatase inhibitor CIP2A, accounting for c-MYC upregulation and stability in HPV+ HNC cells. CIP2A mRNA expression negatively correlated with autophagy gene expression in tumor tissues from HNC patients, showing, for the first time, its implication in a transcriptional autophagic context. Both CIP2A and c-MYC knock-down, as well as pharmacological downregulation of c-MYC, resulted in increased resistance to cisplatin treatment. Our results not only show a novel way by which HPV oncoproteins manipulate the host machinery but also provide more insights into the role of autophagy in chemoresistance, with possible implications for targeted HPV-positive HNC therapy.

The Dual Functions of Andrographolide in the Epstein–Barr Virus-Positive Head-and-Neck Cancer Cells: The Inhibition of Lytic Reactivation of the Epstein–Barr Virus and the Induction of Cell Death

Andrographolide, a medicinal compound, exhibits several pharmacological activities, including antiviral and anticancer properties. Previously, we reported that andrographolide inhibits Epstein–Barr virus (EBV) lytic reactivation, which is associated with viral transmission and oncogenesis in epithelial cancers, including head-and-neck cancer (HNC) cells. However, the underlying mechanism through which andrographolide inhibits EBV lytic reactivation and affects HNC cells is poorly understood. Therefore, we investigated these mechanisms using EBV-positive HNC cells and the molecular modeling and docking simulation of protein. Based on the results, the expression of EBV lytic genes and viral production were significantly inhibited in andrographolide-treated EBV-positive HNC cells. Concurrently, there was a reduction in transcription factors (TFs), myocyte enhancer factor-2D (MEF2D), specificity protein (SP) 1, and SP3, which was significantly associated with a combination of andrographolide and sodium butyrate (NaB) treatment. Surprisingly, andrographolide treatment also significantly induced the expression of DNA Methyltransferase (DNMT) 1, DNMT3B, and histone deacetylase (HDAC) 5 in EBV-positive cells. Molecular modeling and docking simulation suggested that HDAC5 could directly interact with MEF2D, SP1, and SP3. In our in vitro study, andrographolide exhibited a stronger cytotoxic effect on EBV-positive cells than EBV-negative cells by inducing cell death. Interestingly, the proteome analysis revealed that the expression of RIPK1, RIPK3, and MLKL, the key molecules for necroptosis, was significantly greater in andrographolide-treated cells. Taken together, it seems that andrographolide exhibits concurrent activities in HNC cells; it inhibits EBV lytic reactivation by interrupting the expression of TFs and induces cell death, probably via necroptosis.

BMSC-HNC Interaction: Exploring Effects on Bone Integrity and Head and Neck Cancer Progression.

In recent research, the tumor microenvironment has been shown to attract mesenchymal stromal cells (MSCs), which is of particular interest due to its implications for cancer progression. The study focused on understanding the interaction between bone marrow-derived MSCs (BMSCs) and head and neck cancer (HNC) cells. This interaction was found to activate specific markers, notably the osteogenic marker alkaline phosphatase and the oncogene Runx2. These activations corresponded with the release of collagenase enzymes, MMP9 and MMP2. To gain insights into bone resorption related to this interaction, bovine bone slices were used, supporting the growth of "heterogeneous spheroids" that contained both BMSCs and HNC cells. Through scanning electron microscopy and energy-dispersive X-ray (EDX) analysis, it was observed that these mixed spheroids were linked to a notable increase in bone degradation and collagen fiber exposure, more so than spheroids of just BMSCs or HNC cells. Furthermore, the EDX results highlighted increased nitrogen content on bone surfaces with these mixed clusters. Overall, the findings underscore the significant role of BMSCs in tumor growth, emphasizing the need for further exploration in potential cancer treatment strategies.

New Propargyloxy Derivatives of Galangin, Kaempferol and Fisetin-Synthesis, Spectroscopic Analysis and In Vitro Anticancer Activity on Head and Neck Cancer Cells.

Head and neck cancer (HNC) therapy is limited; therefore, new solutions are increasingly being sought among flavonoids, which exhibit numerous biological properties, including potential anticancer activity. However, because they are mostly insoluble in water, are unstable and have low bioavailability, they are subjected to chemical modification to obtain new derivatives with better properties. This study aimed to synthesize and analyze new propargyloxy derivatives of galangin, kaempferol and fisetin, and to evaluate their anticancer activity against selected HNC cell lines. The obtained derivatives were assessed by spectroscopic analysis; next, their anticancer activity was evaluated using a flow cytometer and real-time cell analysis. The results showed that only the fisetin derivative was suitable for further analysis, due to the lack of crystal formation of the compound. The fisetin derivative statistically significantly increases the number of cells in the G2/M phase (p < 0.05) and increases cyclin B1 levels. A statistically significant increase in the number of apoptotic cells after being exposed to the tested compound was also observed (p < 0.05). The data indicate that the obtained fisetin derivative exhibits anticancer activity by affecting the cell cycle and increasing apoptosis in selected HNC lines, which suggests its potential use as a new medicinal agent in the future.