Antitumor activity of afatinib in EGFR T790M-negative human oral cancer therapeutically targets mTOR/Mcl-1 signaling axis.

PURPOSE: This study investigates the role and effectiveness of the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) in oral cancer, focusing on the clinical relevance of EGFR and myeloid cell leukemia-1 (Mcl-1) in head and neck cancers (HNCs). It aims to explore the molecular mechanism of afatinib, a TKI, in treating human oral cancer. METHODS: We conducted an in silico analysis using databases like The Cancer Genome Atlas, Gene Expression Omnibus, and Clinical Proteomic Tumor Analysis Consortium, along with immunohistochemistry staining, to study EGFR and Mcl-1 expression in HNCs. For investigating afatinib's anticancer properties, we performed various in vitro and in vivo analyses, including trypan blue exclusion assay, Western blotting, 4'-6-diamidino-2-phenylindole staining, flow cytometry, quantitative real-time PCR, Mitochondrial membrane potential assay, overexpression vector construction, transient transfection, and a tumor xenograft model. RESULTS: Higher expression levels of EGFR and Mcl-1 were observed in HNC patient tissues compared to normal tissues, with their co-expression significantly linked to poor prognosis. There was a strong correlation between EGFR and Mcl-1 expressions in oral cancer patients. Afatinib treatment induced apoptosis and suppressed Mcl-1 in oral cancer cell lines without the EGFR T790M mutation. The mechanism of afatinib-induced apoptosis involved the EGFR/mTOR/Mcl-1 axis, as shown by the effects of mTOR activator MHY1485 and inhibitor rapamycin. Afatinib also increased Bim expression, mitochondrial membrane permeabilization, and cytochrome c release. It significantly lowered tumor volume without affecting body, liver, and kidney weights. CONCLUSION: Afatinib, targeting the EGFR/mTOR/Mcl-1 axis, shows promise as a therapeutic strategy for oral cancer, especially in patients with high EGFR and Mcl-1 expressions.

Zingiber officinale promotes autophagy and apoptosis in human oral cancer through the C/EBP homologous protein.

The rhizome of Zingiber officinale (Z. officinale), commonly known as ginger, has been characterized as a potential drug candidate due to its antitumor effects. However, the chemotherapeutic effect of ginger on human oral cancer remains poorly understood. In this study, we examined the effects of an ethanol extract of Z. officinale rhizomes (ZOE) on oral cancer and identified the components responsible for its pharmacological activity. ZOE exerts its inhibitory activity in oral cancer by inducing both autophagy and apoptosis simultaneously. Mechanistically, ZOE-induced autophagy and apoptosis in oral cancer are attributed to the reactive oxygen species (ROS)-mediated endoplasmic reticulum stress response. Additionally, we identified two active components of ZOE, 1-dehydro-6-gingerdione and 8-shogaol, which were sufficient to stimulate autophagy initiation and apoptosis induction by enhancing CHOP expression. These results suggest that ZOE and its two active components induce ROS generation, upregulate CHOP, initiate autophagy and apoptosis, and hold promising therapeutics against human oral cancer.

In vitro antimetastatic potential of pseudolaric acid B in HSC-3 human tongue squamous carcinoma cell line.

OBJECTIVE: Pseudolaric acid B (PAB) is a novel diterpenoid derived from the traditional Chinese medicinal herb Cortex pseudolaricis that exerts anticancer, anti-inflammatory, and immunomodulatory properties. While the anticancer potential of PAB has been studied, its effects on metastasis have not been well-studied. This study aims to determine the inhibitory effects of PAB on HSC-3 human tongue squamous cell carcinoma (TSCC) cell line. DESIGN: Cell viability and soft agar colony formation assays were conducted to assess cellular proliferation and in vitro tumorigenic capacity of TSCC cells, respectively. Additionally, wound healing, transwell migration, and invasion assays were conducted to monitor the aggressive behavior of TSCC cells. Furthermore, Western blotting analysis was conducted to reveal the signaling pathways involved in the modulation of epithelial-mesenchymal transition (EMT). RESULTS: The migratory and invasive capacities of HSC-3 cells were suppressed by PAB irrespective of their proliferation states. PAB's effects on EMT involved upregulation of E-cadherin expression and downregulation of Twist; these were concomitantly accompanied by downregulated phosphorylation of epidermal growth factor receptor (EGFR). CONCLUSIONS: PAB suppresses human TSCC in vitro by regulating Twist/E-cadherin through the EGFR signaling pathway. PAB may have potential as a candidate antimetastatic drug for TSCC treatment.

Caffeic acid phenethyl ester: Unveiling its potential as a potent apoptosis inducer for combating hypopharyngeal squamous cell carcinoma.

Hypopharyngeal squamous cell carcinoma (HSCC) is a relatively rare form of head and neck cancer that is notorious for its poor prognosis and low overall survival rate. This highlights the need for new therapeutic options for this malignancy. The objective of the present study was to examine the ability of caffeic acid phenethyl ester (CAPE), which is an active compound found in propolis, to combat HSCC tumor growth. CAPE exerted its tumor­suppressive activity in HSCC cell lines through the induction of apoptosis. Mechanistically, the CAPE­mediated apoptotic process was attributed to the perturbation of the mitochondrial membrane potential and the activation of caspase­9. CAPE also modulated survivin and X­linked inhibitor of apoptosis, which are potent members of the inhibitors of apoptosis protein family, either through transcriptional or post­translational regulation, leading to HSCC cell line death. Therefore, the findings of the present study suggested that CAPE is an effective treatment alternative for HSCC via the stimulation of mitochondria­dependent apoptosis.

Apoptotic activity of genipin in human oral squamous cell carcinoma in vitro by regulating STAT3 signaling.

Genipin, a natural compound derived from the fruit of Gardenia jasminoides Ellis, was reported to have activity against various cancer types. In this study, we determined the underlying mechanism for genipin-induced cell death in human oral squamous cell carcinoma (OSCC). The growth-inhibitory effects of genipin in human OSCC cells was examined by the Cell Counting Kit-8 and soft agar assays. The effects of genipin on apoptosis were assessed by nuclear morphological changes by 4',6-diamidino-2-phenylindole staining, measurement of the sub-G1 population, and Annexin V-fluorescein isothiocyanate/propidium iodide double staining. The underlying mechanism of genipin activity was analyzed by western blot analysis, subcellular fractionation of the nucleus and cytoplasm, immunocytochemistry, and quantitative real-time polymerase chain reaction. Genipin inhibited the growth of OSCC cells and induced apoptosis, which was mediated by a caspase-dependent pathway. Genipin reduced the phosphorylation of signal transducer and activator of transcription 3 (STAT3) at Tyr705 and its nuclear localization. Furthermore, inhibition of p-STAT3Tyr705 levels following genipin treatment was required for the reduction of survivin and myeloid cell leukemia-1 (Mcl-1) expression, leading to apoptotic cell death. The genipin-mediated reduction in survivin and Mcl-1 expression was caused by transcriptional and/or posttranslational regulatory mechanisms. The results provide insight into the regulatory mechanism by which genipin induces apoptotic cell death through the abrogation of nuclear STAT3 phosphorylation and suggest that genipin may represent a potential therapeutic option for the treatment of human OSCC.

Neuropilin-2 acts a critical determinant for epithelial-to-mesenchymal transition and aggressive behaviors of human head and neck cancer.

PURPOSE: Neuropilin-2 (NRP2) is a multifunctional single-pass transmembrane receptor that binds to two disparate ligands, namely, vascular endothelial growth factors (VEGFs) and semaphorins (SEMAs). It is reportedly involved in neuronal and vascular development. In this study, we uncovered the exact functional role of NRP2 and its molecular mechanism during aggressive behaviors and lymph node (LN) metastasis in human head and neck cancer (HNC) and identified algal methanol extract as a potential novel NRP2 inhibitor. METHODS: In silico analyses and immunohistochemistry were used to investigate the relationship between NRP2 expression and the prognosis of HNC patients. The functional role of NRP2 on the proliferation, migration, invasion, and cancer stem cell (CSC) properties of HNC cells was examined by MTS, soft agar, clonogenic, transwell migration and invasion assays, and sphere formation assays. Signaling explorer antibody array, western blot, and qPCR were performed toward the investigation of a molecular mechanism that is related to NRP2. RESULTS: NRP2 was highly expressed in HNC and positively correlated with LN metastasis and advanced tumor stage and size in patients. Using loss- or gain-of-function approaches, we found that NRP2 promoted the proliferative, migratory, and invasive capacities of human HNC cells. Furthermore, NRP2 regulated Sox2 expression to exhibit aggressiveness and CSC properties of human HNC cells. We demonstrated that p90 ribosomal S6 kinase 1 (RSK1) elevates the aggressiveness and CSC properties of human HNC cells, possibly by mediating NRP2 and Sox2. Zeb1 was necessary for executing the NRP2/RSK1/Sox2 signaling pathway during the induction of epithelial-to-mesenchymal transition (EMT) and aggressive behaviors of human HNC cells. Moreover, the methanol extract of Codium fragile (MECF) repressed NRP2 expression, inhibiting the RSK1/Sox2/Zeb1 axis, which contributed to the reduction of aggressive behaviors of human HNC cells. CONCLUSIONS: These findings suggest that NRP2 is a critical determinant in provoking EMT and aggressive behaviors in human HNC through the RSK1/Sox2/Zeb1 axis, and MECF may have the potential to be a novel NRP2 inhibitor for treating metastasis in HNC patients.

Podophyllotoxin reduces the aggressiveness of human oral squamous cell carcinoma through myeloid cell leukemia­1.

Podophyllotoxin (PPT), which is derived from the podophyllum plant, exhibits marked cytotoxic effects against cancer cells; however, the precise molecular mechanism underlying its activity against human oral squamous cell carcinoma (OSCC) has not been elucidated. In the present study, the mechanism by which PPT induced cytotoxicity in two OSCC cell lines, HSC3 and HSC4, was determined. The effects of PPT on cytotoxicity in HSC3 and HSC4 cells were analyzed using Annexin V/PI double staining, Sub­G1 analysis, soft agar assays, western blotting, and quantitative PCR. The changes in the mitochondrial membrane potential were assessed using a JC­1 assay and cytosolic and mitochondrial fractionation. A myeloid cell leukemia­1 (Mcl­1) overexpression cell lines were also established to study the role of Mcl­1 on apoptosis. The results showed that PPT inhibited the growth of the two human OSCC cell lines and induced apoptosis, which was accompanied by mitochondrial membrane depolarization. Compared with the control, PPT reduced the expression of Mcl­1 in both cell lines through a proteasome­dependent protein degradation process. Overall, these results suggested that targeting of Mcl­1 protein by PPT induced apoptosis, providing a foundation for further pre­clinical and clinical study of its value in the management of OSCC.

Piperlongumine induces apoptosis and autophagy via the PI3K/Akt/mTOR pathway in KB human cervical cancer cells.

Natural products are continuously being researched to develop safe and effective treatment options for cervical cancer, the fourth most common cancer in women. Piperlongumine (PL), an amide alkaloid mainly present in long pepper, exhibits neuroprotective and anti-cancer properties. However, the specific effect of PL in cervical cancer and the relationship between the anti-cancer pathway and autophagy remain unclear. Therefore, we aimed to investigate PL-induced apoptosis in KB human cervical cancer cells and the relationship between apoptosis and autophagy therein. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and wound-healing assays showed that PL treatment suppressed KB cell viability and proliferation. Apoptosis was identified through 4',6-diamidino-2-phenylindole and annexin V-propidium iodide staining, increased cleaved-poly (ADP-ribose) polymerase and Bcl-2 associated X levels, and decreased B cell lymphoma 2 levels. Acridine orange staining and increased microtubule-associated protein 1A/1B-light chain 3-II and Beclin-1 levels confirmed autophagy. We determined that KB cell-related autophagy exerted cytoprotective effects using the autophagy inhibitors 3-methyladenine and hydroxychloroquine. PL treatment promoted apoptosis by inhibiting the phosphatidylinositol-3-kinase (PI3K)/protein kinase B/mammalian target of rapamycin pathway in KB cells; inhibiting the pathway using PI3K inhibitors increased autophagy. We suggest that PL is a potential natural anticancer agent for cervical cancer treatment.

Mechano-modulation of T cells for cancer immunotherapy.

Immunotherapy, despite its promise for future anti-cancer approach, faces significant challenges, such as off-tumor side effects, innate or acquired resistance, and limited infiltration of immune cells into stiffened extracellular matrix (ECM). Recent studies have highlighted the importance of mechano-modulation/-activation of immune cells (mainly T cells) for effective caner immunotherapy. Immune cells are highly sensitive to the applied physical forces and matrix mechanics, and reciprocally shape the tumor microenvironment. Engineering T cells with tuned properties of materials (e.g., chemistry, topography, and stiffness) can improve their expansion and activation ex vivo, and their ability to mechano-sensing the tumor specific ECM in vivo where they perform cytotoxic effects. T cells can also be exploited to secrete enzymes that soften ECM, thus increasing tumor infiltration and cellular therapies. Furthermore, T cells, such as chimeric antigen receptor (CAR)-T cells, genomic engineered to be spatiotemporally controllable by physical stimuli (e.g., ultrasound, heat, or light), can mitigate adverse off-tumor effects. In this review, we communicate these recent cutting-edge endeavors devoted to mechano-modulating/-activating T cells for effective cancer immunotherapy, and discuss future prospects and challenges in this field.

Targeting tumor-intrinsic PD-L1 suppresses the progression and aggressiveness of head and neck cancer by inhibiting GSK3ß-dependent Snail degradation.

PURPOSE: PD-L1 is an immune checkpoint protein that allows cells to evade T-cell-mediated immune responses. Herein, we uncover a tumor-intrinsic mechanism of PD-L1 that is responsible for the progression and aggressiveness of HNC and reveal that the extracts of a brown alga can target the tumor-intrinsic signaling pathway of PD-L1. METHODS: The biological functions of PD-L1 in the proliferation and aggressiveness of HNC cells in vitro were examined by metabolic activity, clonogenic, tumorigenicity, wound healing, migration, and invasion assays. The clinical importance of PD-L1 in the prognosis of patients with HNC was analyzed by immunohistochemistry. The relationship between PD-L1 and EMT was confirmed via western blotting, qPCR, and immunocytochemistry. RESULTS: Through our in silico approach, we found that PD-L1 was upregulated in HNC and was correlated with an unfavorable clinical outcome in patients with HNC. PD-L1 was crucial for promoting tumor growth, both in vitro and in vivo. High expression of PD-L1 was closely correlated with LN metastasis in OSCC. PD-L1 facilitated the cytoskeletal reorganization and aggressiveness of HNC cells. Moreover, PD-L1 enhanced the EMT of HNC cells by regulating the Snail/vimentin axis. Consistently, MEIO suppressed the PD-L1/Snail/vimentin axis, thereby inhibiting the aggressiveness of HNC cells. Inhibition of PD-L1 induced by PD-L1 silencing or MEIO treatment caused Snail degradation through a GSK3ß-dependent mechanism. The tumor-intrinsic function of PD-L1 could be attributed to the regulation of the GSK3ß/Snail/vimentin axis. CONCLUSION: The discovery of MEIO targeting the tumor-intrinsic function of PD-L1 may prove particularly valuable for the development of novel and effective anticancer drug candidates for HNCs overexpressing PD-L1.

Inhibition of focal adhesion kinase/paxillin axis by caffeic acid phenethyl ester restrains aggressive behaviors of head and neck squamous cell carcinoma in vitro.

OBJECTIVE: Caffeic acid phenethyl ester (CAPE), one of the components of propolis that is produced by honeybees, reportedly suppresses multiple diseases, including bacterial infection, inflammation, and cancer. We aimed to investigate the inhibitory effects of CAPE on epithelial-mesenchymal transition (EMT) status and aggressive behaviors of human head and neck squamous cell carcinoma (HNSCC) in vitro and the underlying signaling pathway. DESIGN: To examine the cell growth and in vitro tumorigenic potential of HNSCC cells, cell viability and soft agar colony formation assays, respectively, were performed. Transwell migration and invasion assays were conducted to monitor HNSCC cells' aggressive behaviors. Western blotting and immunocytochemistry analyses were done to investigate the signaling pathway responsible for relieving EMT progression and HNSCC cell aggressiveness. RESULTS: CAPE inhibited the in vitro tumorigenic potential of SNU-1041 cells stimulated by epidermal growth factor and suppressed the migratory and invasive capacities of SNU-1041 cells, irrespective of their cell proliferation state. CAPE was, at least partially, capable of inhibiting EMT progression by upregulating E-cadherin expression, which was accompanied by the reduction of phosphorylated focal adhesion kinase (FAK) and Paxillin. The inhibition of the FAK/Paxillin axis by PF-562271 was sufficient to alleviate the EMT progression through the induction of E-cadherin and aggressive behaviors of SNU-1041 cells. CONCLUSIONS: CAPE has a therapeutic potential as an anti-metastatic drug candidate for HNSCC therapy targeting the FAK/Paxillin axis.

Reappraisal of tubulopapillary hidradenoma-like tumor of the mandible: Suggested change in nomenclature to reflect tumor origin.

Several cases of intraosseous mandibular tumors have been reported under the name "tubulopapillary hidradenoma-like tumor of the mandible (TPHLTM)." However, the intraosseous occurrence of sweat gland tumors needs to be reappraised. The aim of this review was to propose a new name for these tumors to reflect the possible tumor origin. In view of the incidence and the tissue of origin, TPHLTM is more likely to be a salivary gland tumor than a sweat gland tumor. Among salivary gland tumors, a recently described salivary neoplasm called "sialadenoma papilliferum-like intraductal papillary tumor (SP-IPT)" seems to be histologically and genetically identical to tubulopapillary hidradenoma. Therefore, we proposed that the term TPHLTM be replaced by "SP-IPT of the mandible," which better explains its origin and could help in clarifying the nature of SP-IPT.

Chrysin Induces Apoptosis and Autophagy in Human Melanoma Cells via the mTOR/S6K Pathway.

Chrysin is known to exert anti-inflammatory, antioxidant, and anticancer effects. The aim of this study was to investigate the anticancer effects of chrysin in the human melanoma cells A375SM and A375P. The results obtained demonstrated successful inhibition of the viability of these cells by inducing apoptosis and autophagy. This was confirmed by the level of apoptosis-related proteins: Bax and cleaved poly (ADP-ribose) polymerase both increased, and Bcl-2 decreased. Moreover, levels of LC3 and Beclin 1, both autophagy-related proteins, increased in chrysin-treated cells. Autophagic vacuoles and acidic vesicular organelles were observed in both cell lines treated with chrysin. Both cell lines showed different tendencies during chrysin-induced autophagy inhibition, indicating that autophagy has different effects depending on the cell type. In A375SM, the early autophagy inhibitor 3-methyladenine (3-MA) was unaffected; however, cell viability decreased when treated with the late autophagy inhibitor hydroxychloroquine (HCQ). In contrast, HCQ was unaffected in A375P; however, cell viability increased when treated with 3-MA. Chrysin also decreased the phosphorylation of mTOR/S6K pathway proteins, indicating that this pathway is involved in chrysin-induced apoptosis and autophagy for A375SM and A375P. However, studies to elucidate the mechanisms of autophagy and the action of chrysin in vivo are still needed.

Myricetin induces apoptosis and autophagy in human gastric cancer cells through inhibition of the PI3K/Akt/mTOR pathway.

Myricetin, a natural flavonoid present in berries, nuts, and green tea, is well-known for its anticancer properties. Even though several previous studies have reported the anticancer effects induced by myricetin, these effects have not yet been confirmed in the adenocarcinoma gastric cell line (AGS). Moreover, the exact mechanisms of myricetin-induced apoptosis and autophagy have not been clearly identified either. Therefore, in this study, we aimed to examine the role of myricetin in inducing apoptosis and autophagy in AGS gastric cancer cells. First, the survival rate of AGS gastric cancer cells was assessed using the 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) cell viability assay. Thereafter, the rate of apoptosis was analyzed using4',6-diamidino-2-phenylindole (DAPI) staining as well as annexin V and propidium iodide (PI) staining, and the expression of the proteins associated with apoptosis, PI3K/Akt/mTOR pathway, and autophagy was examined by western blotting. We observed that myricetin reduced the survival rate of AGS gastric cancer cells by inhibiting the PI3K/Akt/mTOR pathway, thereby inducing apoptosis and autophagy. Similar results were also obtained in vivo, and tumor growth was inhibited. Therefore, in the AGS gastric cancer cells, myricetin seems to inhibit the PI3K/Akt/mTOR pathway, which in turn leads to apoptosis in vitroand in vivo, cell-protective autophagy, as well as inhibition of cancer cell proliferation. These results indicate the potential of myricetin as a natural anticancer agent.

Myeloid cell leukemia-1 expression in cancers of the oral cavity: a scoping review.

BACKGROUND: B cell lymphoma-2 (Bcl-2) family members play important roles in cell survival as well as cell death. The role of myeloid cell leukemia-1 (Mcl-1), an important member of the Bcl-2 family, is well established in hematopoietic malignancies. However, the association between Mcl-1 and oral cavity, cancers is not clearly defined. METHODS: A scoping review was conducted until June 30, 2021, using four major databases, PubMed, Scopus, Web of Science, and Embase. Medical subject headings keywords for Mcl-1, along with its other identifiers, and head and neck cancers (only oral cavity tumors) were used to evaluate the expression, function, molecular association, and therapeutic approach of Mcl-1 in oral cavity cancers and precancers. FINDINGS: Mcl-1 expression was associated with the progression of oral cavity cancers. The molecular mechanism and pathways of Mcl-1 in oral cavity cancers established via experimental results have been highlighted in this review. Moreover, the various synthetic and naturally derived therapeutic agents targeting Mcl-1 have been documented. NOVELTY/IMPROVEMENT: Based on our present review, Mcl-1 appears to be an effective anticancer target that can be used in the therapeutic management of oral cancers.

Metabolite profiling of a Sargassum micracanthum methanol extract with in vitro efficacy against human head and neck squamous cell carcinoma aggressiveness.

OBJECTIVE: Extracts from the brown algae Sargassum micracanthum have documented anti-viral, anti-oxidant, and anti-inflammatory activities as well as potential anti-tumor efficacy against several cancer types. Here, we evaluated the inhibitory effect and molecular mechanisms of methanol extract of S. micracanthum (MESM) on the aggressiveness of human head and neck squamous cell carcinoma (HNSCC) using in vitro cell culture-based models. DESIGN: To test the potential efficacy of MESM on the migratory and invasive properties of HNSCC cells, we used wound healing, transwell cell migration and invasion assays. Proteome profiling and functional in silico analysis were applied to investigate the possible modes of action by MESM. We also examined the metabolite profiling of MESM using gas chromatography/mass spectrometry. RESULTS: MESM inhibited the motility of human HNSCC cell lines as well as invasiveness without influencing cell survival. Proteome profiling identified 19 oncogenic proteins significantly downregulated by MESM treatment. Protein-protein interaction network and gene ontology analyses revealed that Tie2 and associated angiogenic signaling pathway components were significantly enriched among these downregulated oncogenic proteins, which was confirmed by validating the reduced Tie2 expression in MESM treatment groups. Metabolite profiling of MESM identified six-carbon sugar alcohols such as D-sorbitol and/or D-mannitol as the main bioactive compounds. D-sorbitol and D-mannitol effectively reduced Tie2 expression and the aggressiveness of human HNSCC cell lines. CONCLUSIONS: These findings suggest that six-carbon sugar alcohols in MESM have promising anti-cancer efficacy for the treatment of human HNSCC and further identify Tie2 signaling components as potential treatment targets.

BRAF V600E and previously unidentified KRAS G12C mutations in odontogenic tumors may affect MAPK activation differently depending on tumor type.

Although several types of odontogenic tumors share the same mutations in MAPK pathway genes, their effects on MAPK activation remain unclarified. This study aimed to evaluate the associations between these mutations and ERK phosphorylation in ameloblastoma and mixed odontogenic tumors (MOTs) and to analyze the expression pattern of phosphorylated ERK (p-ERK) for determining the involvement of MAPK activation in the development and progression of odontogenic tumors. Forty-three odontogenic tumors consisting of 18 ameloblastomas and 25 MOTs were analyzed for BRAF, KRAS, and NRAS mutations by Sanger sequencing. The expressions of BRAFV600E protein and p-ERK were detected by immunohistochemistry. The associations between mutation status and p-ERK expression were statistically analyzed. The effect of BRAFV600E inhibition on MAPK activation was investigated in ameloblastoma cells. In benign MOTs, BRAFV600E mutations were neither expressed at the protein level nor associated with p-ERK expression. In contrast, BRAFV600E -mutant ameloblastic fibrosarcoma showed co-expression of BRAF V600E protein and p-ERK, especially in the sarcomatous component. In ameloblastoma, p-ERK was predominantly expressed in the tumor periphery showing a significant correlation with BRAFV600E mutations, and in vitro BRAFV600E inhibition decreased ERK phosphorylation. KRASG12C mutations, previously unidentified in odontogenic tumors, were detected in one case each of benign MOT and ameloblastoma; only the latter was high-p-ERK. In conclusion, unlike in benign MOTs, BRAFV600E and KRASG12C mutations lead to MAPK activation in ameloblastoma, suggesting their role as therapeutic targets. p-ERK intratumoral heterogeneity indicates that MAPK pathway activation may be associated with sarcomatous proliferation of ameloblastic fibrosarcoma and infiltrative behavior of ameloblastoma.

PD-L1 Expression Correlated with Clinicopathological Factors and Akt/Stat3 Pathway in Oral SCC.

Programmed cell death ligand 1 (PD-L1) is an immune checkpoint molecule that inhibits immune responses. The physiological and prognostic role of the PD-L1 signaling pathway in the oral maxillofacial region is unclear. This study aimed to investigate the role of PD-L1 in the progression of oral squamous cell carcinoma (OSCC). Furthermore, clinicopathological factors related to PD-L1 expression were examined in patients with OSCC through immunohistochemistry (IHC) of tissue sections and through an in vitro study in OSCC cells. The medical records, radiographic findings, and mortality referrals of 81 patients obtained from the National Statistical Office were reviewed. IHC was performed on tissue specimens of these patients to determine the expression levels of PD-L1, which showed significant statistical differences based on age, tumor size, TNM stage, cervical lymph node metastasis, and locoregional recurrence. Patients with a high PD-L1 expression had significantly poorer survival rates. Multivariate analysis using the Cox proportional model confirmed the high relative risk ratio for high PD-L1 expression, TNM stage, and neck node metastasis, all of which were significantly associated with a poor prognosis in patients with OSCC. The in vitro study showed that SAS and YD38 cells transfected with PD-L1 siRNA had significantly increased apoptosis, reduced proliferative capacity, and tumorigenicity.

Effect of PAIP1 on the metastatic potential and prognostic significance in oral squamous cell carcinoma.

Poly Adenylate Binding Protein Interacting protein 1 (PAIP1) plays a critical role in translation initiation and is associated with the several cancer types. However, its function and clinical significance have not yet been described in oral squamous cell carcinoma (OSCC) and its associated features like lymph node metastasis (LNM). Here, we used the data available from Gene Expression Omnibus (GEO), The Cancer Genome Atlas (TCGA), and Clinical Proteomic Tumor Analysis Consortium (CPTAC) to analyze PAIP1 expression in oral cancer. The publicly available data suggests that PAIP1 mRNA and protein levels were increased in OSCC. The high PAIP1 expression was more evident in samples with advanced stage, LNM, and worse pattern of invasion. Moreover, the in vitro experiments revealed that PAIP1 knockdown attenuated colony forming, the aggressiveness of OSCC cell lines, decreasing MMP9 activity and SRC phosphorylation. Importantly, we found a correlation between PAIP1 and pSRC through the analysis of the IHC scores and CPTAC data in patient samples. Our findings suggest that PAIP1 could be an independent prognostic factor in OSCC with LNM and a suitable therapeutic target to improve OSCC patient outcomes.

Withaferin A mitigates metastatic traits in human oral squamous cell carcinoma caused by aberrant claudin-1 expression.

Abnormal expression of claudin-1 (CLDN1) has important roles in carcinogenesis and metastasis in various cancers. The role of CLDN1 in human oral squamous cell carcinoma (OSCC) remains unknown. Here, we report the functional role of CLDN1 in metastasis of human OSCC, as a potential target regulated by withaferin A. From gene expression profiling with microarray technology, we found that the majority of notable differentially expressed genes were classified into migration/invasion category. Withaferin A impaired the motility of human OSCC cells in vitro and suppressed metastatic nodule formation in an in vivo metastasis model, both associated with reduced CLDN1. CLDN1 overexpression enhanced metastatic nodule formation in vivo, resulting in severe metastatic lesions in lung tissue. Moreover, CLDN1 expression was positively correlated to lymphatic metastasis in OSCC patients. The impaired motility of human OSCC cells upon withaferin A treatment was restored by CLDN1 overexpression. Furthermore, upregulation of let-7a induced by withaferin A was inversely correlated to CLDN1 expression. Overall, these give us an insight into the function of CLDN1 for prognosis and treatment of human OSCC, substantiating further investigation into the use of withaferin A as good anti-metastatic drug candidate.