Immunohistochemical assessment of growth factor signaling molecules: MAPK, Akt, and STAT3 pathways in oral epithelial precursor lesions and squamous cell carcinoma

miR-504 knockout regulates tumor cell proliferation and immune cell infiltration to accelerate oral cancer development

miR-504 plays a pivotal role in the progression of oral cancer. However, the underlying mechanism remains elusive in vivo. Here, we find that miR-504 is significantly down-regulated in oral cancer patients. We generate miR-504 knockout mice (miR-504-/-) using CRISPR/Cas9 technology to investigate its impact on the malignant progression of oral cancer under exposure to 4-Nitroquinoline N-oxide (4NQO). We show that the deletion of miR-504 does not affect phenotypic characteristics, body weight, reproductive performance, or survival in mice, but results in changes in the blood physiological and biochemical indexes of the mice. Moreover, with 4NQO treatment, miR-504-/- mice exhibit more pronounced pathological changes characteristic of oral cancer. RNA-seq shows that the differentially expressed genes observed in samples from miR-504-/- mice with oral cancer are involved in regulating cell metabolism, cytokine activation, and lipid metabolism-related pathways. Additionally, these differentially expressed genes are significantly enriched in lipid metabolism pathways that influence immune cell infiltration within the tumor microenvironment, thereby accelerating tumor development progression. Collectively, our results suggest that knockout of miR-504 accelerates malignant progression in 4NQO-induced oral cancer by regulating tumor cell proliferation and lipid metabolism affecting immune cell infiltration.

Single-cell transcriptomics dissects premalignant progression in proliferative verrucous leukoplakia

OBJECTIVE

Proliferative verrucous leukoplakia (PVL) is characterized by a spectrum of clinicopathological features and a high risk of malignant transformation. In this study, we aimed to delineate the dynamic changes in molecular signature during PVL progression and identify the potential cell subtypes that play a key role in the premalignant evolution of PVL.

METHODS

We performed single-cell RNA sequencing on three biopsy samples from a large PVL lesion. These samples exhibited a histopathological continuum of PVL progression.

RESULTS

By analyzing the transcriptome profiles of 27,611 cells from these samples, we identified ten major cell lineages and revealed that cellular remodeling occurred during the progression of PVL lesions, including epithelial, stromal, and immune cells. Epithelial cells are shifted to tumorigenic states and secretory patterns at the premalignant stage. Immune cells showed growing immunosuppressive phenotypes during PVL progression. Remarkably, two novel cell subtypes INSR+ endothelial cells and ASPN+ fibroblasts, were discovered and may play vital roles in microenvironment remodeling, such as angiogenesis and stromal fibrosis, which are closely involved in malignant transformation.

CONCLUSION

Our work is the first to depict the cellular landscape of PVL and speculate that disease progression may be driven by functional remodeling of multiple cell subtypes.

Azoxystrobin induces apoptosis via PI3K/AKT and MAPK signal pathways in oral leukoplakia progression

Background: Oral leukoplakia (OLK) is one of the oral potentially malignant disorders (OPMDs) with an increased risk of developing oral squamous cell carcinoma (OSCC). There is no ideal therapeutic drug yet. Our previous study showed azoxystrobin (AZOX) inhibited the viability of OLK cells and the incidence of mouse tongue cancer. However, its specific mechanism has not been clarified. Here, we used network pharmacology with experimental validation to investigate the roles and mechanisms of AZOX in OLK.

Methods: The targets of AZOX and OLK were obtained from online databases. The overlapping genes were identified by the Jvenn database. STRING and Cytoscape software were used to construct the PPI network. GO and KEGG enrichment analyses were used to analyze the biological function. Molecular docking and CETSA were used to verify the direct binding between AZOX and its key targets. 4NQO induced mouse tongue carcinogenesis model was constructed to clarify the treatment response of AZOX in vivo. TUNEL staining was performed to detect the effect of AZOX on apoptosis in mouse OLK tissues. CCK8 assay, flow cytometry, and western blot were used to detect the effect of AZOX on cell proliferation and apoptosis in DOK cells. The expression of PI3K/AKT and MAPK markers were analyzed by immunohistochemistry in vivo or by western blot in vitro.

Results: Venn diagram showed 457 overlapping targets, which were involved in the PI3K/AKT, MAPK, and apoptosis pathways, and the top 5 hub modules were TP53, STAT3, AKT1, MAPK1, and PIK3R1. AZOX was bound with the highest force to AKT and PI3K by AutoDock Vina. PyMOL software visualized that AZOX could fit in the binding pocket of the AKT and PI3K. The carcinogenesis rate of the mouse OLK in the high-dose AZOX group was significantly reduced. AZOX induced apoptosis in the OLK tissues and DOK cells, and the expression of PI3K, AKT, p-ERK was decreased, and the expression of p-p38 and p-JNK was increased. CETSA indicated that AZOX might have a direct binding with AKT and PI3K.

Conclusion: AZOX may induce apoptosis via PI3K/AKT and MAPK pathways in OLK. This study reveals the potential therapeutic targets of AZOX in OLK.

Deciphering the pharmacological mechanisms of Scutellaria baicalensis Georgi on oral leukoplakia by combining network pharmacology, molecular docking and experimental evaluations

BACKGROUND

Oral leukoplakia (OLK), an uncharacterized pathological condition that occurs as a white patch in the oral mucosa, is the most common precancerous condition. Scutellaria baicalensis Georgi (SBG) is a medicinal plant with a wide range of pharmacological effects. Increased evidence shows that SBG has potential therapeutic effects on OLK. However, the therapeutic mechanisms of SBG against OLK have not yet been completely elucidated.

PURPOSE

This study aimed to clarify the active components and multi-target mechanisms of SBG against OLK via network pharmacology, molecular docking and experimental evaluations.

STUDY DESIGN AND METHODS

The active components and related targets of SBG were screened by the TCMSP database and Swiss Target Prediction database. Potential therapeutic targets of OLK were collected using the GeneCards and OMIM databases. Then, we established protein-protein interaction (PPI), compound-target-disease (C-T-D), and compound-target-pathway (C-T-P) networks by Cytoscape to identify the main components, core targets, and pharmacological pathways of SBG against OLK via applying data mining techniques and topological parameters. Metascape database was utilized for GO and KEGG pathway analysis. Molecular docking techniques were used to estimate the binding force between the components and the hub genes. Subsequently, a series of in vitro experiments, specifically CCK-8 assay, clone formation assay, wound healing assay, flow cytometry, RT-qPCR and western blotting were conducted for further verification.

RESULTS

There were 25 active components and 31 related target genes in SBG against OLK. PPI analysis showed that Akt1, VEGFA, EGFR, HIF1A and PTGS2 shared the highest centrality among all target genes. KEGG pathway analysis found that PI3K-Akt signaling pathway may occupy core status in the anti-OLK system. Molecular docking results showed that the main active components of SBG had a strong binding affinity to the hub genes. In vitro experiments showed that the leading component baicalein may inhibit proliferation, block cells in the S phase, induce DOK cell apoptosis, and downregulate the mRNA expression of 5 hub genes by inhibiting PI3K/Akt signaling pathway activation.

CONCLUSION

The most predominant component of SBG against OLK was baicalein and the key pathway was PI3K/Akt. The main components and hub genes had robust binding abilities. In vitro experiments showed that baicalein could inhibit the proliferation of DOK cells, induce apoptosis, block the cell cycle, and inhibit the mRNA expression level of the hub genes by inhibiting the PI3K/Akt pathway.

The multifaceted role of STAT3 pathway and its implication as a potential therapeutic target in oral cancer

Oral cancer is one of the leading causes of cancer-related deaths, and it has become a matter of serious concern due to the alarming rise in its incidence rate worldwide. Despite recent advancements in oral cancer treatment strategies, there are no significant improvements in patient's survival rate. Among the numerous cell signaling pathways involved in oral cancer development and progression, STAT3 is known to play a multifaceted oncogenic role in shaping the tumor pathophysiology. STAT3 hyperactivation in oral cancer contributes to survival, proliferation, invasion, epithelial to mesenchymal transition, metastasis, immunosuppression, chemoresistance, and poor prognosis. A plethora of pre-clinical and clinical studies have documented the role of STAT3 in the initiation and development of oral cancer and showed that STAT3 inhibition holds significant potential in the prevention and treatment of this cancer. However, to date, targeting STAT3 activation mainly involves inhibiting the upstream signaling molecules such as JAK and IL-6 receptors. The major challenge in targeting STAT3 lies in the complexity of its phosphorylation- and dimerization-independent functions, which are not affected by disrupting the upstream regulators. The present review delineates the significance of the STAT3 pathway in regulating various hallmarks of oral cancer. In addition, it highlights the STAT3 inhibitors identified to date through various preclinical and clinical studies that can be employed for the therapeutic intervention in oral cancer treatment.

Consequences of the COVID-19 Pandemic and Governmental Containment Policies on the Detection and Therapy of Oral Malignant Lesions-A Retrospective, Multicenter Cohort Study from Germany

Simple Summary

Due to the COVID-19 pandemic, the oncology community was challenged with the need to protect a vulnerable population from a potentially fatal infection without jeopardizing cancer treatments. The impact of the crisis on the medical care of patients with oral cancer is largely unexplored. This multicenter cohort study from Germany aims to assess the consequences of the COVID-19 pandemic by comparing the healthcare of patients during the lockdown and post-lockdown periods in 2020 with the corresponding periods in 2018/19. We found the closure of dental practices during lockdown to possibly delay the diagnosis of oral cancer. Even if during this period no higher incidence of oral cancer was observed, data point to potentially fatal consequences for longer periods of treatment delay.

Abstract

(1) Background: In response to the global COVID-19 pandemic, governmental measures have been undertaken. The impact of the crisis on the healthcare of patients with cancer is largely unexplored. This multicenter cohort study aimed to investigate a potential screening delay and its consequences in patients with oral cancer (OC) during the pandemic. (2) Material and Methods: Data of patients who were first diagnosed with OC during different periods were collected, especially in terms of OC incidence, tumor stage/entity and time to intervention. The periods lockdown (LD) (13 March–16 June 2020), post-lockdown (PLD) (17 June–1 November 2020), and the corresponding equivalents in 2018/19 were differentiated and compared. (3) Results: There was no obvious trend towards a higher incidence of OC or higher tumor stages, whereas a trend towards a shorter time to intervention during the LD2020 could be observed. Subgroup analyses revealed an increased incidence in OC within the PLD2020 in Mainz, which might be explained by the partial closure of dental practices in this federal state during LD. (4) Conclusions: While there was no overall higher incidence of OC, we found closure of practices during LD to possibly delay cancer diagnosis. Therefore, measures must be taken to identify patients at risk and to ensure basic healthcare, especially in the context of dental screening measures.

Recurrence in Oral Premalignancy: Clinicopathologic and Immunohistochemical Analysis

Oral leukoplakia (OL) has a propensity for recurrence and malignant transformation (MT). Herein, we evaluate sociodemographic, clinical, microscopic and immunohistochemical parameters as predictive factors for OL recurrence, also comparing primary lesions (PLs) with recurrences. Thirty-three patients with OL, completely removed either by excisional biopsy or by laser ablation following incisional biopsy, were studied. Selected molecules associated with the STAT3 oncogenic pathway, including pSTAT3, Bcl-xL, survivin, cyclin D1 and Ki-67, were further analyzed. A total of 135 OL lesions, including 97 PLs and 38 recurrences, were included. Out of 97 PLs, 31 recurred at least once and none of them underwent MT, during a mean follow-up time of 48.3 months. There was no statistically significant difference among the various parameters in recurrent vs. non-recurrent PLs, although recurrence was most frequent in non-homogeneous lesions (p = 0.087) and dysplastic lesions recurred at a higher percentage compared to hyperplastic lesions (34.5% vs. 15.4%). Lower levels of Bcl-xL and survivin were identified as significant risk factors for OL recurrence. Recurrences, although smaller and more frequently homogeneous and non-dysplastic compared to their corresponding PLs, exhibited increased immunohistochemical expression of oncogenic molecules, especially pSTAT3 and Bcl-xL. Our results suggest that parameters associated with recurrence may differ from those that affect the risk of progression to malignancy and support OL management protocols favoring excision and close monitoring of all lesions.

Bupivacaine inhibits the malignant biological behavior of oral squamous cell carcinoma cells by inhibiting the activation of ERK1/2 and STAT3

Background

Oral squamous cell carcinoma (OSCC) is an aggressive malignant tumor. Bupivacaine (Bupi), a local anesthetic drug, has been shown to display anti-tumor activity against a variety of tumors.

Methods

We selected OSCC CAL-27 cells as the in vitro model. Cell toxicity, proliferation, apoptosis, and stemness were conducted, respectively. The protein levels of Ki67, PCNA, caspase-3, caspase-9, survivin, SOX2, NANOG, OCT4, STAT3, p-STAT3, ERK1/2, and p-ERK1/2 were evaluated by western blotting. Male BALB/c nude mice xenograft model was used to evaluate the effect of Bupi on tumor growth in vivo.

Results

Compared with the control group, Bupi (0.2, 0.5, or 1 µm) significantly decreased the cell viability and the proliferation of CAL-27 cells. Meanwhile, Bupi significantly promoted apoptosis of CAL-27 cells compared with the control group. Additionally, Bupi inhibited the stemness of CAL-27 cells which was evidenced by a sphere formation assay. Bupi decreased the phosphorylation level of STAT3 and ERK1/2 in a dose-dependent manner. The addition of interferon-γ (IFN-γ, 20 ng/mL) in the experiment verified the role of Bupi on STAT3 and ERK1/2 signaling. In vivo, Bupi (40 µmol/kg) obviously suppressed the weight and size of the xenograft tumor, the number of apoptotic cells and Ki67+ decreased. Also, Bupi treatment inhibited the expression of stem-like marker proteins.

Conclusions

Bupi could be used as an anticancer drug against the growth and stemness ability of OSCC. The underlying mechanism may be due to down-regulation of STAT3 and ERK1/2 signaling. This study provides a new insight for the application of Bupi.

Oral Potentially Malignant Disorders (OPMD): What is the clinical utility of dysplasia grade?

INTRODUCTION

Oral epithelial dysplasia is considered a potential histologic precursor of subsequent squamous cell cancer. As standard clinical practice, pathologists grade dysplasia to assess risk for progression to malignancy. Except for the most advanced grade, severe dysplasia, dysplasia grading has failed to correlate well with the risk to develop invasive cancer. The questions of what process dysplasia grading best represents and what clinical utility dysplasia grading may have are explored.

AREAS COVERED

This narrative review is based on PubMed search with emphasis on papers since 2010. Epithelial dysplasia as a precursor lesion of cancer and dysplasia grading as a risk assessment tool for progression to cancer are discussed. The close clinical association of dysplasia with known carcinogens, alcohol, and tobacco products is presented.

EXPERT OPINION

Oral epithelial dysplasia is often, associated with prolonged exposure to tobacco and alcohol products. With reduction of carcinogen exposure, dysplasia is known to regress in some cases. It is proposed that histologic dysplasia grade together with macroscopic images of dysplastic clinical lesions be used as an educational tool to incentivize patients to reduce their known carcinogen exposure. This strategy has the potential to reduce lesion progression thereby reducing the disease burden of oral cancer.

Antitumor Activity of the Cardiac Glycoside αlDiginoside by Modulating Mcl-1 in Human Oral Squamous Cell Carcinoma Cells

We recently isolated a cardiac glycoside (CG), αldiginoside, from an indigenous plant in Taiwan, which exhibits potent tumor-suppressive efficacy in oral squamous cell carcinoma (OSCC) cell lines (SCC2095 and SCC4, IC₅₀ < 0.2 µM; 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays). Here, we report that αldiginoside caused Sphase arrest and apoptosis, through the inhibition of a series of signaling pathways, including those mediated by cyclin E, phospho-CDC25C (p-CDC25C), and janus kinase/signal transducer and activator of transcription (JAK/STAT)3. αldiginoside induced apoptosis, as indicated by caspase activation and poly (ADP-ribose) polymerase (PARP) cleavage. Equally important, αldiginoside reduced Mcl-1 expression through protein degradation, and overexpression of Mcl-1 partially protected SCC2095 cells from αldiginoside’s cytotoxicity. Taken together, these data suggest the translational potential of αldiginoside to foster new therapeutic strategies for OSCC treatment.

Targeting AKT/mTOR in Oral Cancer: Mechanisms and Advances in Clinical Trials

Oral cancer (OC) is a devastating disease that takes the lives of lots of people globally every year. The current spectrum of treatment modalities does not meet the needs of the patients. The disease heterogeneity demands personalized medicine or targeted therapies. Therefore, there is an urgent need to identify potential targets for the treatment of OC. Abundant evidence has suggested that the components of the protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) pathway are intrinsic factors for carcinogenesis. The AKT protein is central to the proliferation and survival of normal and cancer cells, and its downstream protein, mTOR, also plays an indispensable role in the cellular processes. The wide involvement of the AKT/mTOR pathway has been noted in oral squamous cell carcinoma (OSCC). This axis significantly regulates the various hallmarks of cancer, like proliferation, survival, angiogenesis, invasion, metastasis, autophagy, and epithelial-to-mesenchymal transition (EMT). Activated AKT/mTOR signaling is also associated with circadian signaling, chemoresistance and radio-resistance in OC cells. Several miRNAs, circRNAs and lncRNAs also modulate this pathway. The association of this axis with the process of tumorigenesis has culminated in the identification of its specific inhibitors for the prevention and treatment of OC. In this review, we discussed the significance of AKT/mTOR signaling in OC and its potential as a therapeutic target for the management of OC. This article also provided an update on several AKT/mTOR inhibitors that emerged as promising candidates for therapeutic interventions against OC/head and neck cancer (HNC) in clinical studies.

Impact of the Activation Status of the Akt/mTOR Signalling Pathway on the Clinical Behaviour of Synovial Sarcoma: Retrospective Analysis of 174 Patients at a Single Institution

PURPOSE

Phosphoinositide 3-kinase (PI3K) and the downstream Akt/mammalian target of rapamycin (mTOR) pathway are central to the control of cell proliferation and survival. Although abnormal activation of this pathway has been well established in a variety of tumours, limited studies are available on synovial sarcoma. The aim of this study was to investigate the expression of several key proteins of those pathways in synovial sarcomas and to correlate the expression of these proteins with clinicopathologic features and prognosis.

PATIENTS AND METHODS

A total of 174 patients with synovial sarcomas were recruited for this study. The phosphorylation status of Akt, mTOR, and eukaryotic translation initiation factor 4E binding protein (4E-BP1) was measured by immunohistochemistry assays in formalin-fixed, paraffin-embedded samples. Correlations between the expression levels of these proteins and clinicopathologic features and prognosis were analysed.

RESULTS

The positive rates of phosphorylated (p)Akt, pmTOR, p4E-BP1, and CyclinD1 were 62.7%, 55.6%, 47.1%, and 52.6%, respectively. The positive results of pmTOR, pAkt, and downstream p4E-BP1 were correlated with each other. The positive pAkt, pmTOR, p4E-BP1, and CyclinD1 results were more highly expressed in head and neck and visceral tumours, and positive p4E-BP1 results were correlated with larger size and larger areas of necrosis. In multivariate analysis of clinicopathologic factors, head and neck and visceral location, large tumour size, larger areas of necrosis and frequent mitosis were confirmed as risk factors for shorter overall survival. Positive pAkt, pmTOR and p4E-BP1 results were correlated significantly with shorter overall survival, and CyclinD1 was not in the univariate analysis. The positive pmTOR, pAkt, p4E-BP1, and CyclinD1 results were significantly poor prognostic factors for overall survival, and only positive p4E-BP1 results were significantly associated with shorter event-free survival in multivariate analysis.

CONCLUSION

This study demonstrated the high expression of pAkt, pmTOR, and p4E-BP1 associated with aggressive clinical behaviour in synovial sarcomas and provided evidence for prognostic evaluation and targeted therapy.