Current mouse models of oral squamous cell carcinoma: Genetic and chemically induced models

4-nitroquinoline 1-oxide-induced oral epithelial lesions exhibit time- and stage-dependent changes in the tumor immune microenvironment

Oral tongue squamous cell carcinoma (OTSCC) is the most common cancer of the oral cavity and is associated with high morbidity due to local invasion and lymph node metastasis. Tumor infiltrating lymphocytes (TILs) are associated with good prognosis in oral cancer patients and dictate response to treatment. Ectopic sites for immune activation in tumors, known as tertiary lymphoid structures (TLS), and tumor-associated high-endothelial venules (TA-HEVs), which are specialized lymphocyte recruiting vessels, are associated with a favorable prognosis in OSCC. Why only some tumors support the development of TLS and HEVs is poorly understood. In the current study we explored the infiltration of lymphocyte subsets and the development of TLS and HEVs in oral epithelial lesions using the 4-nitroquinoline 1-oxide (4NQO)-induced mouse model of oral carcinogenesis. We found that the immune response to 4NQO-induced oral epithelial lesions was dominated by T cell subsets. The number of T cells (CD4+, FoxP3+, and CD8+), B cells (B220+) and PNAd+ HEVs increased from the earliest to the latest endpoints. All the immune markers increased with the severity of the dysplasia, while the number of HEVs and B cells further increased in SCCs. HEVs were present already in early-stage lesions, while TLS did not develop at any timepoint. This suggests that the 4NQO model is applicable to study the dynamics of the tumor immune microenvironment at early phases of oral cancer development, including the regulation of TA-HEVs in OTSCC.

Immune checkpoint inhibitor monotherapy is sufficient to promote microenvironmental normalization via the type I interferon pathway in PD-L1-expressing head and neck cancer

Immune checkpoint blockers (ICBs) targeting programmed cell death protein 1 (PD-1) have been proven to be an effective first-line therapy against programmed cell death 1 ligand 1 (PD-L1; also known as CD274 molecule)-expressing head and neck squamous cell carcinoma (HNSCC) in recent KEYNOTE-048 trial. However, associated changes in the tumor microenvironment (TME) and underlying mechanisms remain elusive. Oral tumors in C57/BL6 mice were induced by administering 7,12-dimethylbenzanthracene into the buccal mucosa. Single-cell suspension was isolated from tumor tissue; proliferating cells were injected subcutaneously into the left flank of mice to establish Ajou oral cancer (AOC) cell lines. Subsequently, a syngeneic PD-L1-expressing HNSCC model was developed by injecting AOC cells into the buccal or tongue area. The model recapitulated human HNSCC molecular features and showed reliable in vivo tumorigenicity with significant PD-L1 expression. ICB monotherapy induced global changes in the TME, including vascular normalization. Furthermore, the antitumor effect of ICB monotherapy was superior to those of other therapeutic agents, including cisplatin and inhibitors of vascular endothelial growth factor receptor 2 (VEGFR2). The ICB-induced antitumorigenicity and TME normalization were alleviated by blocking the type I interferon pathway. In summary, ICB monotherapy is sufficient to induce TME normalization in the syngeneic model; the type I interferon pathway is indispensable in realizing the effects of ICBs. Furthermore, these results explain the underlying mechanism of the efficacy of ICB monotherapy against PD-L1-expressing HNSCC in the KEYNOTE-048 trial.

miR-450b promotes cell migration and invasion by inhibiting SERPINB2 in oral squamous cell carcinoma

OBJECTIVE

microRNA-450b (miR-450b) plays an important role in cancer progression; however, its function in oral squamous cell carcinoma (OSCC) remains largely unknown. This study aimed to investigate the action mechanisms of miR-450b in OSCC.

MATERIALS AND METHODS

OSCC animal model was established via continuous induction with single-drug 7, 12-dimethylbenzo[a]anthracene (DMBA). Animal tissue samples were pathologically typed using haematoxylin-eosin (HE) staining. The Cancer Genome Atlas (TCGA) database was used to predict miR-450b and SERPINB2 expression in head and neck squamous cell carcinoma (HNSCC). qRT-PCR and Western blotting were used to detect gene and protein expression in OSCC tissue and cells, respectively. OSCC cell proliferation, growth, migration and invasion were detected using CCK-8, colony formation, transwell migration and matrigel invasion assays, respectively. Bioinformatic tools were used to predict miR-450b target genes. Dual-luciferase reporter assay was used to verify targeting between miR-450b and SERPINB2. Finally, small interfering RNA (siRNA) was used to reduce SERPINB2 expression to detect its effect on tumourigenesis.

RESULTS

Four stages of OSCC carcinogenesis (normal oral epithelium, simple epithelial hyperplasia, dysplasia and OSCC) were identified. miR-450b was found to be overexpressed in OSCC animal samples, HNSCC samples and human OSCC cells. Upregulation of miR-450b significantly promoted OSCC cell proliferation, colony formation, migration and invasion, while its downregulation had the opposite effect. SERPINB2 was found to be a miR-450b target gene, and its expression was negatively correlated with miR-450b expression. Altering SERPINB2 expression effectively inhibited OSCC cell invasion, metastasis and epithelial-mesenchymal transition (EMT).

CONCLUSIONS

miR-450b plays a key role in OSCC tumourigenesis by regulating OSCC cell migration, invasion and EMT via SERPINB2.

Development of an in vitro microfluidic model to study the role of microenvironmental cells in oral cancer metastasis

Metastasis occurs when cancer cells leave the primary tumour and travel to a secondary site to form a new lesion. The tumour microenvironment (TME) is recognised to greatly influence this process, with for instance the vascular system enabling the dissemination of the cells into other tissues. However, understanding the exact role of these microenvironmental cells during metastasis has proven challenging. Indeed, in vitro models often appear too simplistic, and the study of the interactions between different cell types in a 3D space is limited. On the other hand, even though in vivo models incorporate the TME, observing cells in real-time to understand their exact role is difficult. Horizontal compartmentalised microfluidic models are a promising new platform for metastasis studies. These devices, composed of adjacent microchannels, can incorporate multiple cell types within a 3D space. Furthermore, the transparency and thickness of these models also enables high quality real-time imaging to be performed. This paper demonstrates how these devices can be successfully used for oral squamous cell carcinoma (OSCC) metastasis studies, focusing on the role of the vascular system in this process. Conditions for co-culture of OSCC cells and endothelial cells have been determined and staining protocols optimised. Furthermore, several imaging analysis techniques for these models are described, enabling precise segmentation of the different cell types on the images as well as accurate assessment of their phenotype. These methods can be applied to any study aiming to understand the role of microenvironmental cell types in cancer metastatic dissemination, and overcome several challenges encountered with current in vitro and in vivo models. Hence, this new in vitro model capable of recapitulating important aspects of the cellular complexity of human metastatic dissemination can ultimately contribute to replacing animal studies in this field.

A scientometric study of chemical carcinogen-induced experimental oral carcinogenesis with emphasis on chemopreventive agents

Background/purpose

4-Nitroquinoline 1-oxide (4NQO)-induced tongue carcinoma and 7,12-dimethlybenz(a)anthracene (DMBA)-induced cheek pouch carcinoma are the most common and classical chemical carcinogen-induced animal models of oral carcinogenesis. The purpose of this study was to provide the research trends and characteristics of 4NQO- and DMBA-induced experimental oral carcinogenesis.

Materials and methods

The papers on both 4NQO- and DMBA-induced experimental oral carcinogenesis were published since 1962. All the eligible papers were retrieved on 12 May 2023 from the Scopus database.

Results

There were 506 and 349 papers on 4NQO- and DMBA-induced experimental oral carcinogenesis with 10,152 and 6306 citations, respectively. The common distinctive keywords such as rat, tongue neoplasms, drinking water, tumor microenvironment, and cyclooxygenase (COX)-2 were identified in the papers on 4NQO; and the common keywords such as hamster, cheek pouch, lipid peroxidation, glutathione, antioxidants, and topical drug administration were identified in the papers on DMBA. Importantly, 105 and 65 potential chemopreventive agents were identified from the papers on 4NQO and DMBA, respectively. Furthermore, 15 promising agents such as COX-2 inhibitor, curcumin, garlic were researched concurrently in both the two animal models.

Conclusion

This study for the first time reports the scientometric characteristics of 4NQO- and DMBA-induced experimental oral carcinogenesis. Importantly, we identify a valuable profile for oral cancer chemopreventive agents, which will aid researchers and investigators in studying oral cancer chemoprevention.

Towards system genetics analysis of head and neck squamous cell carcinoma using the mouse model, cellular platform, and clinical human data

Head and neck squamous cell cancer (HNSCC) is a leading global malignancy. Every year, More than 830 000 people are diagnosed with HNSCC globally, with more than 430 000 fatalities. HNSCC is a deadly diverse malignancy with many tumor locations and biological characteristics. It originates from the squamous epithelium of the oral cavity, oropharynx, nasopharynx, larynx, and hypopharynx. The most frequently impacted regions are the tongue and larynx. Previous investigations have demonstrated the critical role of host genetic susceptibility in the progression of HNSCC. Despite the advances in our knowledge, the improved survival rate of HNSCC patients over the last 40 years has been limited. Failure to identify the molecular origins of development of HNSCC and the genetic basis of the disease and its biological heterogeneity impedes the development of new therapeutic methods. These results indicate a need to identify more genetic factors underlying this complex disease, which can be better used in early detection and prevention strategies. The lack of reliable animal models to investigate the underlying molecular processes is one of the most significant barriers to understanding HNSCC tumors. In this report, we explore and discuss potential research prospects utilizing the Collaborative Cross mouse model and crossing it to mice carrying single or double knockout genes (e.g. Smad4 and P53 genes) to identify genetic factors affecting the development of this complex disease using genome-wide association studies, epigenetics, microRNA, long noncoding RNA, lncRNA, histone modifications, methylation, phosphorylation, and proteomics.

4-nitroquinoline 1-oxide induces immune cells death to onset early immunosuppression during oral squamous cell carcinoma development

4-Nitroquinoline N-oxide (4-NQO) and its derivatives react with genomic DNA to form stable quinolone monoadducts, which are highly mutagenic and genotoxic. While the chronic high-dose exposure of epithelial cells to a carcinogen such as 4-NQO leads to tumor development, its effect on other cells has not been explored yet. Since the immunosuppression due to aberrant immunological profile is recognized as a significant cause in tumors, here we determine the interaction between 4-NQO and immune cells both in vivo and in vitro, and its effect on oral squamous cell carcinoma (OSCC) progression in a murine model. Immune cell profiling of the spleen and peripheral blood revealed a significant decrease in the B-cell population in 4-NQO-exposed mice than the untreated group. Additionally, γδ T and CD5+ B lymphocyte populations decreased at both pre- and post-cancerous stages of OSCC. These results suggested that 4-NQO induced tumor transition from pre-malignant lesions to OSCC by altering certain immune cells systemically. Next, to establish the effect of 4-NQO on immune cells, human B- and T-cell lines were subjected to 4-NQO; the reduction in cell viability, increase in DNA damage response marker, and induction of apoptosis were more pronounced in B than T cells. Altogether, our results indicated that in addition to the genotoxicity of oral epithelial cells, 4-NQO potentiates long-range effects on specific immune cells to induce cell death to cause very-early immunosuppressive response during oral carcinogenesis, and thus immunosuppression and tumor development are coevolved.

Oral squamous cell carcinomas: state of the field and emerging directions

Oral squamous cell carcinoma (OSCC) develops on the mucosal epithelium of the oral cavity. It accounts for approximately 90% of oral malignancies and impairs appearance, pronunciation, swallowing, and flavor perception. In 2020, 377,713 OSCC cases were reported globally. According to the Global Cancer Observatory (GCO), the incidence of OSCC will rise by approximately 40% by 2040, accompanied by a growth in mortality. Persistent exposure to various risk factors, including tobacco, alcohol, betel quid (BQ), and human papillomavirus (HPV), will lead to the development of oral potentially malignant disorders (OPMDs), which are oral mucosal lesions with an increased risk of developing into OSCC. Complex and multifactorial, the oncogenesis process involves genetic alteration, epigenetic modification, and a dysregulated tumor microenvironment. Although various therapeutic interventions, such as chemotherapy, radiation, immunotherapy, and nanomedicine, have been proposed to prevent or treat OSCC and OPMDs, understanding the mechanism of malignancies will facilitate the identification of therapeutic and prognostic factors, thereby improving the efficacy of treatment for OSCC patients. This review summarizes the mechanisms involved in OSCC. Moreover, the current therapeutic interventions and prognostic methods for OSCC and OPMDs are discussed to facilitate comprehension and provide several prospective outlooks for the fields.

Preclinical tumor mouse models for studying esophageal cancer

Preclinical models are extensively employed in cancer research because they can be manipulated in terms of their environment, genome, molecular biology, organ systems, and physical activity to mimic human behavior and conditions. The progress made in in vivo cancer research has resulted in significant advancements, enabling the creation of spontaneous, metastatic, and humanized mouse models. Most recently, the remarkable and extensive developments in genetic engineering, particularly the utilization of CRISPR/Cas9, transposable elements, epigenome modifications, and liquid biopsies, have further facilitated the design and development of numerous mouse models for studying cancer. In this review, we have elucidated the production and usage of current mouse models, such as xenografts, chemical-induced models, and genetically engineered mouse models (GEMMs), for studying esophageal cancer. Additionally, we have briefly discussed various gene-editing tools that could potentially be employed in the future to create mouse models specifically for esophageal cancer research.

KRAS mutations upregulate Runx1 to promote occurrence of head and neck squamous cell carcinoma

Gene mutations play an important role in head and neck squamous cell carcinoma (HNSCC) by not only promoting the occurrence and progression of HNSCC but also affecting sensitivity to treatment and prognosis. KRAS is one of the most frequently mutated oncogenes, which has been reported to have a mutation rate from 1.7% to 12.7% and may lead to poor prognosis in HNSCC, but its role remains unclear. Here, we found that the KRAS mutation can promote HNSCC generation through synergism with 4-Nitroquinoline-1-Oxide(4NQO). Mechanistically, KRAS mutations can significantly upregulate Runx1 to promote oral epithelial cell proliferation and migration and inhibit apoptosis. Runx1 inhibitor Ro 5-3335 can effectively inhibit KRAS-mutated HNSCC progression both in vitro and in vivo. These findings suggest that the KRAS mutation plays an important role in HNSCC and that Runx1 may be a novel therapeutic target for KRAS-mutated HNSCC.

Inducible TgfbR1 and Pten deletion in a model of tongue carcinogenesis and chemoprevention

Head and neck squamous cell carcinoma (HNSCC) is a significant public health problem, with a need for novel approaches to chemoprevention and treatment. Preclinical models that recapitulate molecular alterations that occur in clinical HNSCC patients are needed to better understand molecular and immune mechanisms of HNSCC carcinogenesis, chemoprevention, and efficacy of treatment. We optimized a mouse model of tongue carcinogenesis with discrete quantifiable tumors via conditional deletion of Tgfβr1 and Pten by intralingual injection of tamoxifen. We characterized the localized immune tumor microenvironment, metastasis, systemic immune responses, associated with tongue tumor development. We further determined the efficacy of tongue cancer chemoprevention using dietary administration of black raspberries (BRB). Three Intralingual injections of 500 µg tamoxifen to transgenic K14 Cre, floxed Tgfbr1, Pten (2cKO) knockout mice resulted in tongue tumors with histological and molecular profiles, and lymph node metastasis similar to clinical HNSCC tumors. Bcl2, Bcl-xl, Egfr, Ki-67, and Mmp9, were significantly upregulated in tongue tumors compared to surrounding epithelial tissue. CD4+ and CD8 + T cells in tumor-draining lymph nodes and tumors displayed increased surface CTLA-4 expression, suggestive of impaired T-cell activation and enhanced regulatory T-cell activity. BRB administration resulted in reduced tumor growth, enhanced T-cell infiltration to the tongue tumor microenvironment and robust antitumoral CD8+ cytotoxic T-cell activity characterized by greater granzyme B and perforin expression. Our results demonstrate that intralingual injection of tamoxifen in Tgfβr1/Pten 2cKO mice results in discrete quantifiable tumors suitable for chemoprevention and therapy of experimental HNSCC.

Proposal of a secure and efficient protocol for a murine oral carcinogenesis model induced by 4-nitroquinoline-1-oxide (4NQO)

An important rat model using the chemical carcinogen 4-nitroquinoline-1-oxide (4NQO) has been described for the study of the process of oral carcinogenesis. This model replicates the gradual progression seen in oral carcinoma patients. However, due to its high level of toxicity, its use in fundamental research is challenging. Here, we propose a secure and efficient modified protocol based on a lower dose of 4NQO concentration as well as an increased water supply and hypercaloric diet, in order to reduce the damage caused to the animals during the process of oral carcinogenesis. Twenty-two male Wistar rats were exposed to 4NQO, evaluated clinically once a week and euthanized at 12 and 20 weeks for histopathological analysis. The protocol involves a staggered dose of 4NQO up to a concentration of 25 ppm, associated with two days of pure water, a 5% glucose solution once a week and a hypercaloric diet. This modified protocol prevents the immediate consequences of the carcinogen. At week 7, all animals displayed clinically evident tongue lesions. From a histological perspective, after 12 weeks of 4NQO exposure, 72.7% of the animals developed epithelial dysplasia and 27.3% developed in situ carcinoma. In the group exposed for 20 weeks, epithelial dysplasia and in situ carcinoma were diagnosed in one case each, whereas invasive carcinoma was diagnosed in 81.8% of the cases. Nonsignificant modification of animal's behavior and weight was observed. This new proposed 4NQO protocol was secure and effective for studying oral carcinogenesis and can be used to conduct lengthy investigations.

Preclinical models in head and neck squamous cell carcinoma

Head and neck cancer is the sixth most frequent cancer type. Drug resistance and toxicity are common challenges of the existing therapies, making the development of reliable preclinical models essential for the study of the involved molecular mechanisms as well as for eventual intervention approaches that improve the clinical outcome. Preclinical models of head and neck squamous cell carcinoma have been traditionally based on cell lines and murine models. In this review, we will go over the most frequently used preclinical models, from immortalised-cell and primary tumour cultures in monolayer or 3D, to the currently available animal models. We will scrutinise their efficiency in mimicking the molecular and cellular complexity of head and neck squamous cell carcinoma. Finally, the challenges and the opportunities of other envisaged putative approaches, as well as the potential of the preclinical models to further develop personalised therapies will be discussed.

4-nitroquinoline-1-oxide (4NQO) induced oral carcinogenesis: A systematic literature review

OBJECTIVE

Based on a critical review of published studies, we aimed to develop a good practice guide for using 4-nitroquinoline-1-oxide (4NQO) as an inducer of oral carcinogenesis in Wistar rats.

DESIGN

A systematic search was performed on Medline Ovid, PubMed, Embase, Web of Science, and Scopus databases. The SYRCLE's risk of bias tool was used to assess the quality of the studies.

RESULTS

Thirty-five articles met the selection criteria; 22 (62.9%) of them administered 4NQO systemically in drinking water, with a mean concentration of 30.2 ppm (SD±15.9) and during a mean period of 20.8 (SD±7.8) weeks. The other 13 (37.1%) studies performed topical applications of 4NQO painting the oral mucosa of the animals three times a week (100%) with a mean period of administration of 16.8 (SD±7.0) weeks. Different 4NQO concentrations used for other periods achieved significant tumor development. Most studies didn't perform quantitative clinical analysis, and the histopathological diagnosis/grading criteria varied considerably.

CONCLUSIONS

A poor description of solution care, adverse effects, and the number of losses were observed, and the reporting of these features needs to be improved. Suggestions to guide the development of future research are provided.

Fat and exposure to 4-nitroquinoline-1-oxide causes histologic and inflammatory changes in murine livers

Risk factors for liver cancer include tobacco use, alcohol consumption, obesity, and male sex. Administration of 4-nitroquinonline-1-oxide (4NQO) in drinking water mimics the effects of tobacco and leads to oral carcinoma in mice. This study compared the effects of diets high and low in saturated fat (HF and LF, respectively), and sex, on liver histopathology in 4NQO-treated mice and controls. We hypothesized that 4NQO would cause histopathological changes in liver, and that a HF diet would increase hepatic pathology when compared to the LF diet. Mice (C57Bl/6, 36/sex), were divided into a low fat (10 kcal% fat; LF) or high fat (60 kcal% fat, HF) diet. Mice were further subdivided into one of 3 water treatment groups for 17 weeks: water (control), vehicle (1.25% propylene glycol in water [PG]), or 4NQO in (50 μg/ml; 4NQO). All mice were subsequently given water alone for 6 more weeks. Upon euthanasia, livers were harvested, fixed, sectioned, and stained with hematoxylin and eosin (H&E). H&E slides were graded for histopathology; frozen liver samples were analyzed for triglyceride content. Trichrome stained sections were graded for fibrosis. CD3+ T cells, CD68+ macrophages, and Ly6+ neutrophils were detected by immunohistochemistry. Compared to water controls, 4NQO-treatment caused mouse liver histopathological changes such as fibrosis, and increases in hepatic neutrophils, T cells, and macrophages. HF diet exacerbated pathological changes compared to LF diet. Male controls, but not females, demonstrated severe steatosis and increased triglyceride content. 4NQO treatment decreased hepatic fat accumulation, even in animals on a HF diet. In conclusion, this murine model of oral cancer may serve as a model to study the effects of tobacco and diet on liver.

Long non-coding RNA LINC00472 inhibits oral squamous cell carcinoma via miR-4311/GNG7 axis

Emerging studies indicate that long non-coding RNAs play important roles in oral squamous cell carcinoma (OSCC). However, the function of the majority of long non-coding RNAs is still unclear. Recently, LINC00472 has been reported to play crucial roles in multiple cancers. However, the role of LINC00472 in oral squamous cell carcinoma (OSCC) is still not clear. This study found that LncRNA LINC00472 was significantly down-regulated in several squamous cell carcinoma cancer tissues and OSCC cell lines. Over-expression of LINC00472 in OSCC cells inhibited OSCC progression and alleviated OSCC immune responses. Additionally, we confirmed that LINC00472 functioned as an hsa-miR-4311 sponge and regulated the expression of GNG7 (guanine nucleotide-binding protein, gamma 7). Also, we found that LINC00472 over-expression could suppress xenograft tumor growth in vivo. Our study provides evidence that LINC00472 plays an essential role in inhibiting oral squamous cell carcinoma progression and affecting immune responses by directly binding to hsa-miR-4311 to regulate the expression of GNG7 positively.

Oral carcinogenesis triggers a nociceptive behavior and c-Fos expression in rats' trigeminal pathway

OBJECTIVE

To recognize changes that occur along the trigeminal pathway in oral cancer in order to establish an effective approach to pain control.

METHODS

Wistar rats were divided into control and 4-NQO-groups for 8, 12, 16, or 20 weeks. 4-NQO suspension was administered on the animals` tongues. Mechanical hyperalgesia, assessment of facial expressions and an open field test were performed. After euthanasia, the animals' tongues were removed for macro and microscopic analysis. c-Fos expression was analyzed in the trigeminal pathway structures.

RESULTS

4-NQO induced time-dependent macroscopic lesions that were compatible with neoplastic tumors. Histopathological analysis confirmed oral squamous cell carcinoma in 50% of the animals on the 20th week. There was a significant nociceptive threshold reduction during the first two weeks, followed by a threshold return to the baseline levels, decreasing again from the 12th week. Facial nociceptive expression scores were observed on the 20th week, while increased grooming and exploratory activity were observed on the 8th week. Trigeminal ganglion showed an increased c-Fos immunoexpression on the 20th week and in the trigeminal subnucleus caudalis, it occurred on the 16th and 20th. The long-term carcinogenic exposure caused changes in the nociceptive behavior and c-Fos expression in the rats' trigeminal pathway.

Long non-coding RNA LINC01296 promotes progression of oral squamous cell carcinoma through activating the MAPK/ERK signaling pathway via the miR-485-5p/PAK4 axis

INTRODUCTION

Long intergenic non-protein-coding RNA 1296 (LINC01296), a newly identified lncRNA, can function as an oncogenic driver to promote the development of multiple carcinomas. However, the effect of LINC01296 on oral squamous cell carcinoma (OSCC) is still unclear.

MATERIAL AND METHODS

We determined the expression and role of LINC01296 in OSCC tissues and cell lines. The cell viability, migration and invasion were determined by MTT, wound healing assay and transwell assay, respectively. Flow cytometry was used for detecting cell cycle and apoptosis. The interaction and association between LINC01296, microRNA-485-5p (miR-485-5p) and p21 (RAC1) activated kinase 4 (PAK4) were analyzed by RNA immunoprecipitation (RIP) and luciferase reporter assays. The xenograft mouse model was established to detect the effect of LINC01296 on OSCC tumor growth.

RESULTS

Our study showed that LINC01296 was over-expressed in OSCC tissues and cell lines. The level of LINC01296 was positively correlated with the patient's tumor node metastasis (TNM) stage and nodal invasion. Knockdown of LINC01296 effectively inhibits cell viability, migration and invasion but promotes cell apoptosis in vitro. The in vivo experiment showed that LINC01296 knockdown inhibited OSCC tumor growth. The following analysis indicated that LINC01296 acted as a ceRNA for miR-485-5p, and PAK4 was identified as a direct target of miR-485-5p. Furthermore, we found that the effects of LINC01296 on OSCC progression were through regulating the expression of PAK4/p-MEK/p-ERK via sponging miR-485-5p.

CONCLUSIONS

LINC01296 promote the cell cycle, proliferation, migration and invasion, and inhibit apoptosis of OSCC cells through activating the MAPK/ERK signaling pathway via sponging miR-485-5p to regulate PAK4 expression. These results suggested that the LINC01296/miR-485-5p/PAK4 axis was closely associated with OSCC progression. Our study provides a new insight into the molecular pathogenesis of OSCC, and may supply novel biomarkers for diagnosis and therapy of OSCC.

Extracellular ATP Induced S-Phase Cell Cycle Arrest via P2Y Receptor-Activated ERK Signaling in Poorly Differentiated Oral Squamous Cell Carcinoma SAS Cells

Extracellular ATP in the tumor microenvironment exhibits either pro- or antitumor effect via interaction with P2Y receptors, but the intracellular signaling and functional roles of P2Y receptors in oral squamous cell carcinoma (OSCC) are unclear. We aimed to study the effect of ATP on OSCC cell lines and the potential mechanisms involved. Through GEPIA dataset analysis, high expression levels of mRNA encoding P2Y receptors, the ATP-induced G protein-coupled receptors, were associated with better overall patient survival in head and neck squamous cell carcinoma. qPCR analysis showed that the poorly differentiated OSCC SAS cell line, had higher P2RY1 expression level compared to the well-differentiated H103 and H376 cell lines. Western blotting and flow cytometry analyses revealed that ATP phosphorylated ERK and elevated intracellular calcium signaling in all tested cell lines. A significant S-phase cell cycle arrest was observed in SAS, and preincubation with the MEK inhibitor PD0325901 reversed the ATP-induced S-phase arrest. We further demonstrated that ATP induced a slight reduction in cell count and colony formation yet significant apoptosis in SAS. Overall, we postulate that the ATP-induced S-phase arrest effect in SAS cells may be regulated through P2Y receptor-mediated ERK signaling, thus suggesting a potential antitumor effect of ATP via interaction with its distinct profile of P2Y receptors.

TNFα Signaling Is Increased in Progressing Oral Potentially Malignant Disorders and Regulates Malignant Transformation in an Oral Carcinogenesis Model

Oral carcinogenesis represents a multi-stage process which encompasses several genetic and molecular changes that promote the progression of oral potentially malignant disorders (OPMDs) to oral squamous cell carcinomas (OSCCs). A better understanding of critical pathways governing the progression of OMPDs to OSCCs is critical to improve oncologic outcomes in the future. Previous studies have identified an important role of tumor necrosis factor α (TNFα) and TNF receptor 1 (TNFR1) in the invasiveness of oral cancer cell lines. Here, we investigate the expression of TNFα and TNFR1 in human OPMDs that progress to OSCC compared to non-progressing OPMDs utilizing fluorescent immunohistochemistry (FIHC) to show increased TNFα/TNFR1 expression in progressing OPMDs. In order to interrogate the TNFα/TNFR1 signaling pathway, we utilized a 4-nitroquinoline 1-oxide (4-NQO) mouse model of oral carcinogenesis to demonstrate that TNFα/TNFR1 expression is upregulated in 4-NQO-induced OSCCs. TNFα neutralization decreased serum cytokines, inhibited the development of invasive lesions and reduced tumor-associated neutrophils in vivo. Combined, this data supports the role of TNFα in oral malignant transformation, suggesting that critical immunoregulatory events occur downstream of TNFR1 leading to malignant transformation. Our results advance the understanding of the mechanisms governing OSCC invasion and may serve as a basis for alternative diagnostic and therapeutic approaches to OPMDs and OSCC management.

BRCA1/Trp53 heterozygosity and replication stress drive esophageal cancer development in a mouse model

BRCA1 germline mutations are associated with an increased risk of breast and ovarian cancer. Recent findings of others suggest that BRCA1 mutation carriers also bear an increased risk of esophageal and gastric cancer. Here, we employ a Brca1/Trp53 mouse model to show that unresolved replication stress (RS) in BRCA1 heterozygous cells drives esophageal tumorigenesis in a model of the human equivalent. This model employs 4-nitroquinoline-1-oxide (4NQO) as an RS-inducing agent. Upon drinking 4NQO-containing water, Brca1 heterozygous mice formed squamous cell carcinomas of the distal esophagus and forestomach at a much higher frequency and speed (∼90 to 120 d) than did wild-type (WT) mice, which remained largely tumor free. Their esophageal tissue, but not that of WT control mice, revealed evidence of overt RS as reflected by intracellular CHK1 phosphorylation and 53BP1 staining. These Brca1 mutant tumors also revealed higher genome mutation rates than those of control animals; the mutational signature SBS4, which is associated with tobacco-induced tumorigenesis; and a loss of Brca1 heterozygosity (LOH). This uniquely accelerated Brca1 tumor model is also relevant to human esophageal squamous cell carcinoma, an often lethal tumor.

Defining the Role of Immunotherapy in the Curative Treatment of Locoregionally Advanced Head and Neck Cancer: Promises, Challenges, and Opportunities

Recent advancements in the development of immunotherapies have raised the hope for patients with locally-advanced HNSCC (LA-HNSCC) to achieve improved oncologic outcomes without the heavy burden of treatment-related morbidity. While there are several ongoing late phase clinical trials that seek to determine whether immunotherapy can be effectively employed in the definitive setting, initial results from concurrent immuno-radiotherapy therapy trials have not shown strong evidence of benefit. Encouragingly, evidence from preclinical studies and early-phase neoadjuvant studies have begun to show potential pathways forward, with therapeutic combinations and sequences that intentionally spare tumor draining lymphatics in order to maximize the synergy between definitive local therapy and immunotherapy. The intent of this review is to summarize the scientific rationale and current clinical evidence for employing immunotherapy for LA-HNSCC as well as the ongoing efforts and challenges to determine how to optimally deliver and sequence immunotherapy alongside traditional therapeutics. In both the preclinical and clinical settings, we will discuss the application of immunotherapies to both surgical and radiotherapeutic management of HNSCC.

Effector T cell responses unleashed by regulatory T cell ablation exacerbate oral squamous cell carcinoma

Immune suppression by CD4+FOXP3+ regulatory T (Treg) cells and tumor infiltration by CD8+ effector T cells represent two major factors impacting response to cancer immunotherapy. Using deconvolution-based transcriptional profiling of human papilloma virus (HPV)-negative oral squamous cell carcinomas (OSCCs) and other solid cancers, we demonstrate that the density of Treg cells does not correlate with that of CD8+ T cells in many tumors, revealing polarized clusters enriched for either CD8+ T cells or CD4+ Treg and conventional T cells. In a mouse model of carcinogen-induced OSCC characterized by CD4+ T cell enrichment, late-stage Treg cell ablation triggers increased densities of both CD4+ and CD8+ effector T cells within oral lesions. Notably, this intervention does not induce tumor regression but instead induces rapid emergence of invasive OSCCs via an effector T cell-dependent process. Thus, induction of a T cell-inflamed phenotype via therapeutic manipulation of Treg cells may trigger unexpected tumor-promoting effects in OSCC.

EGCG inhibits growth of tumoral lesions on lip and tongue of K-Ras transgenic mice through the Notch pathway

Epigallocatechin-3-gallate (EGCG), the main active ingredient of green tea, exhibits low toxic side effect and versatile bioactivities, and its anti-cancer effect has been extensively studied. Most of the studies used cancer cell lines and xenograft models. However, whether EGCG can prevent tumor onset after cancer-associated mutations occur is still controversial. In the present study, Krt14-cre/ERT-Kras transgenic mice were developed and the expression of K-RasG12D was induced by tamoxifen. Two weeks after induction, the K-Ras mutant mice developed exophytic tumoral lesions on the lips and tongues, with significant activation of Notch signaling pathway. Administration of EGCG effectively delayed the time of appearance, decreased the size and weight of tumoral lesions, relieved heterotypic hyperplasia of tumoral lesions, and prolonged the life of the mice. The Notch signaling pathway was significantly inhibited by EGCG in the tumoral lesions. Furthermore, EGCG significantly induced cell apoptosis and inhibited the proliferation of tongue cancer cells by blocking the activation of Notch signaling pathway. Taken together, these results indicate EGCG as an effective chemotherapeutic agent for tongue cancer by targeting Notch pathway.

Ubiquitin D Promotes Progression of Oral Squamous Cell Carcinoma via NF-Kappa B Signaling

Ubiquitin D (UBD) is highly upregulated in many cancers, and plays a pivotal role in the pathophysiological processes of cancers. However, its roles and underlying mechanisms in oral squamous cell carcinoma (OSCC) are still unclear. In the present study, we investigated the role of UBD in patients with OSCC. Quantitative real-time polymerase chain reaction and Western blot were used to measure the expression of UBD in OSCC tissues. Immunohistochemistry assay was used to detect the differential expressions of UBD in 244 OSCC patients and 32 cases of normal oral mucosae. In addition, CCK-8, colony formation, wound healing and Transwell assays were performed to evaluate the effect of UBD on the cell proliferation, migration, and invasion in OSCC. Furthermore, a xenograft tumor model was established to verify the role of UBD on tumor formation in vivo. We found that UBD was upregulated in human OSCC tissues and cell lines and was associated with clinical and pathological features of patients. Moreover, the overexpression of UBD promoted the proliferation, migration and invasion of OSCC cells; however, the knockdown of UBD exerted the opposite effects. In this study, our results also suggested that UBD promoted OSCC progression through NF-κB signaling. Our findings indicated that UBD played a critical role in OSCC and may serve as a prognostic biomarker and potential therapeutic target for OSCC treatment.

Genetically engineered mouse models of esophageal cancer

BACKGROUND

Esophageal cancer is the most common cause of cancer-related death worldwide with a diverse geographical distribution, poor prognosis, and diagnosis in advanced stages of the disease. Identification of the mechanisms involved in esophageal cancer development is evaluative to improve outcomes for patients. Genetically engineered mouse models (GEMMs) of cancer provide the physiologic, molecular, and histologic features of the human tumors to determine the pathogenesis and treatments for cancer, hence exhibiting a source of tremendous potential for oncology research. The advancement of cancer modeling in mice has improved to the extent that researchers can observe and manipulate the disease process in a specific manner. Despite the significant differences between mice and humans, mice can be great models for human oncology researches due to similarities between them at the molecular and physiological levels. Due to most of the existing esophageal cancer GEMMs do not propose an ideal system for pathogenesis of the disease, genetic risks, and microenvironment exposure, so identification of challenges in GEM modeling and well-developed technologies are required to obtain the most value for patients. In this review, we describe the biology of human and mouse, followed by the exciting esophageal cancer mouse models with a discussion of applicability and challenges of these models for generating new GEMMs in future studies.

Can propranolol act as a chemopreventive agent during oral carcinogenesis? An experimental animal study

The multistep process of oral carcinogenesis provides a biological rationale for the use of chemoprevention in individuals at increased risk of developing oral cancer. We aimed to determine if low doses of propranolol can prevent the development of oral cancer using a tobacco-relevant and p53-associated animal model of cancer initiation. Twenty-six Wistar rats were randomly allocated into two groups, vehicle, and propranolol. All animals received 4-nitroquinoline N-oxide (4NQO) at 25 ppm diluted in the drinking water for 20 weeks. Animals from the propranolol group received propranolol (0.1 mg/kg) 5 days per week by gavage for 18 weeks. The clinical analysis was performed by measuring the area of the lesion and assessment of scores based on lesion appearance (papule; plaque; nodule or ulcerated). Histopathological analysis was performed to determine the presence of epithelial dysplasia or invasive squamous cell carcinoma (SCC). The average lesion area in 4NQO + vehicle and in 4NQO + propranolol groups were 0.20  and 0.28 mm2, respectively (P = 0.53). The percentage of cases clinically graded as papules, thick plaques, nodular areas, and ulcerated lesions was similar between groups (P = 0.94). Histopathological diagnosis also did not differ between groups (P = 0.65), with 54.5 and 70% of cases being diagnosed as SCC in 4NQO and in 4NQO + propranolol groups, respectively. In conclusion, daily doses propranolol at 0.1 mg/kg were not as effective as a chemopreventive therapy in an animal model of 4NQO-induced carcinogenesis.

N-nitrosodiethylamine induces inflammation of liver in mice

OBJECTIVES

For designing early treatment for liver cancer, it is important to prepare an animal model to evaluate cancer prevention treatment by using inflammation disease. The hepatocarcinogenic N-Nitrosodiethylamine (NDEA) has been reportedly able to produce free radicals that cause liver inflammation leading to liver carcinoma. This study aimed to evaluate the inflammation disease model of mice induced with hepatocarcinogenic NDEA for five weeks induction.

METHODS

The BALB-c mice were induced with NDEA 25 mg/kg of body weight once a week for five weeks intraperitonially and it was then evaluated for the body weight during study periods. The mice were then sacrificed and excised for evaluating their organs including physical and morphological appearances and histopathology evaluations.

RESULTS

The results showed a significant decrease of body weight of mice after five times induction of 25 mg NDEA/kgBW per week intraperitonially. Different morphological appearances and weight of mice organs specifically for liver and spleen had also been observed. The histopathology examination showed that there were hepatic lipidosis and steatohepatitis observed in liver and spleen, respectively that might indicate the hepatocellular injury.

CONCLUSIONS

It can be concluded that inducing mice with NDEA intraperitonially resulted in fatty liver disease leading to progress of cancer disease.

Systems genetics analysis of oral squamous cell carcinoma susceptibility using the mouse model: current position and new perspective

Oral squamous cell carcinoma (OSCC) is one of the most common human malignancies with complex etiology and poor prognosis. Although environmental carcinogens and carcinogenic viruses are still considered the main etiologic factors for OSCC development, genetic factors obviously play a key role in the initiation and progression of this neoplasm, given that not all individuals exposed to carcinogens develop the same severity of the disease, if any. Identifying genetic loci modulating OSCC risk may have several important clinical implications, including early detection, prevention and developing new treatment strategies. Due to limitations in controlled and standardized genetic studies in humans, genetic components underlying susceptibility of OSCC development remain largely unknown. A combination of quantitative trait loci mapping in mice, with complementary association studies in humans, has the potential to discover novel cancer risk loci. As of today, a limited number of genetic analyses were applied on rodent models to locate novel genetic loci associated with human OSCC. Here, we discuss the current status of the mouse models use for dissecting the genetic basis of OSCC and highlight how systems genetics analysis using mouse models, may increase our understanding of human OSCC susceptibility.

Assessment of multiple pathways involved in the inhibitory effect of HCG22 on oral squamous cell carcinoma progression

LncRNAs have been proposed to be associated with the tumorigenesis and progression of oral squamous cell carcinoma (OSCC). LncRNA HLA complex group 22 (HCG22) was reported to be lowly expressed and associated with poor prognosis in head and neck squamous cell carcinoma (HNSCC). However, the biological role and related mechanism of HCG22 in OSCC have not been characterized. HCG22 expression in OSCC cells was detected by qRT-PCR. Cell proliferation, invasion, and apoptosis were evaluated by Bromodeoxyuridine (BrdU) proliferation assay, Transwell invasion assay, and flow cytometry analysis, respectively. The protein levels of proliferating cell nuclear antigen (PCNA), E-cadherin, Vimentin, Bcl-2, Bax, protein kinase B (Akt), phosphorylated Akt (p-Akt), mammalian target of rapamycin (mTOR), phosphorylated mTOR (p-mTOR), and β-catenin were detected by western blot. Cell growth evaluation was performed using in vitro colony formation assay and in vivo tumor xenograft assay. We found that HCG22 was weakly expressed in OSCC cells. HCG22 overexpression inhibited cell proliferation and invasion and induced apoptosis in OSCC cells. The levels of PCNA, Vimentin, and Bcl-2 were decreased and E-cadherin and Bax expression was elevated in OSCC cells after HCG22 overexpression. Additionally, HCG22 overexpression inhibited the Akt, mTOR and Wnt/β-catenin pathways. Activation of Akt, mTOR, and Wnt/β-catenin pathways attenuated the anti-tumor property of HCG22 in OSCC cells. Furthermore, HCG22 overexpression inhibited the growth of OSCC cells in vitro and in vivo. In conclusion, HCG22 exerted anti-tumor property in OSCC by inhibiting the Akt, mTOR, and Wnt/β-catenin pathways.

circBICD2 targets miR-149-5p/IGF2BP1 axis to regulate oral squamous cell carcinoma progression

BACKGROUND

Circular RNAs (circRNAs) are related to oral squamous cell carcinoma (OSCC) progression. circRNA bicaudal D cargo adaptor 2 (circBICD2) has been reported to be abnormally expressed in OSCC. However, the function and mechanism of this circRNA in OSCC progression remain largely unknown.

METHODS

circBICD2, microRNA-149-5p (miR-149-5p), and insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) abundances were examined via quantitative reverse transcription polymerase chain reaction or Western blot. The function of circBICD2 was investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), colony formation, flow cytometry, wound healing, transwell, specific kits, Western blot, and xenograft analyses. Dual-luciferase reporter analysis and RNA immunoprecipitation were carried out to analyze the binding interaction.

RESULTS

circBICD2 expression was enhanced in OSCC tissues and cells. circBICD2 silence suppressed OSCC cell proliferation, migration, invasion, and glutaminolysis and facilitated apoptosis. miR-149-5p was targeted via circBICD2 and decreased in OSCC tissues and cells. miR-149-5p knockdown attenuated silence of circBICD2 on the influence of OSCC cell proliferation, apoptosis, migration, invasion, and glutaminolysis. IGF2BP1 was targeted via miR-149-5p, and circBICD2 could regulate IGF2BP1 via miR-149-5p. IGF2BP1 interference constrained OSCC cell proliferation, migration, invasion, and glutaminolysis and promoted apoptosis. circBICD2 silence reduced OSCC cell growth in xenograft model.

CONCLUSION

circBICD2 knockdown repressed OSCC cell proliferation, migration, invasion, and glutaminolysis and increased apoptosis via modulating miR-149-5p/IGF2BP1 axis, which might act as a potential target for OSCC treatment.

HNC0014, a Multi-Targeted Small-Molecule, Inhibits Head and Neck Squamous Cell Carcinoma by Suppressing c-Met/STAT3/CD44/PD-L1 Oncoimmune Signature and Eliciting Antitumor Immune Responses

Simple Summary

Cancer stem cells (CSCs) in head and neck squamous cell carcinoma (HNSCC) possess unlimited self-renewal capacity, resist treatments and induce tumor repopulation after interventions. Here, we observed HNSCC CSCs secreted exosomes containing c-Met, STAT3 (also the phosphorylated form of c-Met and STAT3), CD44, and PD-L1 oncogenic signaling molecules. CSC-derived exosomes, in part, transform fibroblasts (NFs) into cancer-associated fibroblasts (CAFs), establish drug resistance, and an immune-evasive tumor microenvironment (TME). We demonstrated HNC0014, a novel small-molecule drug, suppresses HNSCC tumorigenesis, CSC generation and prevents CAF transformation by decreasing the aforementioned oncogenic signaling molecules’ expression in both HNSCC cells and CSC-derived exosomes.

Abstract

Despite advancements in diagnostic and standard treatment modalities, including surgery, radiotherapy, and chemotherapy, overall survival rates of advanced-stage head and neck squamous cell carcinoma (HNSCC) patients have remained stagnant for over three decades. Failure of these treatment modalities, coupled with post-therapy complications, underscores the need for alternative interventions and an in-depth understanding of the complex signaling networks involved in developing treatment resistance. Using bioinformatics tools, we identified an increased expression of c-Met, STAT3, and CD44 corresponding to a poor prognosis and malignant phenotype of HNSCC. Subsequently, we showed that tumorsphere-derived exosomes promoted cisplatin (CDDP) resistance and colony and tumorsphere formation in parental HNSCC cells, accompanied by an increased level of oncogenic/immune evasive markers, namely, c-Met, STAT3, CD44, and PD-L1. We then evaluated the therapeutic potential of a new small molecule, HNC0014. The molecular docking analysis suggested strong interactions between HNC0014 and oncogenic molecules; c-Met, STAT3, CD44, and PD-L1. Subsequently, we demonstrated that HNC0014 treatment suppressed HNSCC tumorigenic and expression of stemness markers; HNC0014 also reduced cancer-associated fibroblast (CAF) transformation by Exo^sp- and CAF-induced tumorigenic properties. HNC0014 treatment alone suppressed tumor growth in a cisplatin-resistant (SAS tumorspheres) mouse xenograft model and with higher inhibitory efficacy when combined with CDDP. More importantly, HNC0014 treatment significantly delayed tumor growth in a syngeneic mouse HNSCC model, elicited an antitumor immune profile, and reduced the total c-Met, STAT3, and their phosphorylated forms, PD-L1 and CD44, contents in serum exosomes. Collectively, our findings provide supports for HNC0014 as a multi-targeted immunotherapeutic lead compound for further development.

RGS12 Represses Oral Cancer via the Phosphorylation and SUMOylation of PTEN

Oral squamous cell carcinoma (OSCC) is the most common head and neck cancer characterized by aggressive local invasion and metastasis. The pathogenesis of OSCC is mainly due to the accumulation of genetic alterations in epithelial cells, but the underlying mechanism for its development remains unclear. Here, we found that the expression level of regulator of G protein signaling 12 (RGS12) was significantly reduced in human OSCC. To understand the role and mechanism of RGS12 in OSCC, we generated a novel RGS12 global knockout (CMV^Cre/+; RGS12^fl/fl) mouse model by crossing RGS12^fl/fl mice with CMV-Cre transgenic mice and then further induced the mice to develop OSCC by using 4-nitroquinoline 1-oxide (4NQO). Deletion of RGS12 exhibited aggressive OSCC in the tongue compared with the control RGS12^fl/fl mice. Knockdown of RGS12 in OSCC cells significantly increased cell proliferation and migration. Mechanistically, we found that RGS12 associated with phosphatase and tension homolog (PTEN) via the PDZ domain to upregulate the phosphorylation and SUMOylation of PTEN and then correspondingly inactivated the AKT/mTOR signaling pathway. To test the potential therapeutic effect of RGS12 on OSCC, we overexpressed RGS12 in OSCC cells and found a significant inhibition of cancer cell proliferation and migration. Moreover, subcutaneous inoculation of RGS12-overexpressed OSCC cells in NOD scid mice showed a significant reduction in tumor formation. Our findings reveal that RGS12 is an essential tumor suppressor and highlights RGS12 as a potential therapeutic target and prognostic biomarker of OSCC.

The 4-NQO mouse model: An update on a well-established in vivo model of oral carcinogenesis

The early detection and management of oral premalignant lesions (OPMDs) improve their outcomes. Animal models that mimic histological and biological processes of human oral carcinogenesis may help to improve the identification of OPMD at-risk of progression into oral squamous cell carcinoma and to develop preventive strategies for the entire field of cancerization. No animal model is perfectly applicable for investigating human oral carcinogenesis. However, the 4-nitroquinoline 1-oxide (4-NQO) mouse model is well established and mimics several morphological, histological, genomic and molecular features of human oral carcinogenesis. Some of the reasons for the success of this model include its reproducible experimental conditions with limited variation, the possibility of realizing longitudinal studies with invasive intervention or gene manipulation, and sample availability for all stages of oral carcinogenesis, especially premalignant lesions. Moreover, the role of histological and molecular alterations in the field of cancerization (i.e., macroscopically healthy mucosa exposed to a carcinogen) during oral carcinogenesis can be easily explored using this model. In this review, we discuss the advantages and drawbacks of this model for studying human oral carcinogenesis. In summary, the 4-NQO-induced murine oral cancer model is relevant for investigating human oral carcinogenesis, including the immune microenvironment, and for evaluating therapeutic and chemoprevention agents.

Long Non-Coding RNA NKILA Reduces Oral Squamous Cell Carcinoma Development Through the NF-KappaB Signaling Pathway

Objective:

Emerging studies have identified that long non-coding RNAs (lncRNAs) play critical roles in cancer development. This study aims to explore the mechanism of NF-KappaB (NF-κB) interacting lncRNA (NKILA) in the pathological process of oral squamous cell carcinoma (OSCC).

Methods:

NKILA expression in OSCC tissues, paracancerous tissues, and normal human oral keratinocytes and OSCC cell lines was detected using RT-qPCR. KB cells were selected for the follow-up experiments. The role of NKILA in cell proliferation, migration, invasion, and NF-κB signaling pathway was identified using the gain- and loss-of function of NKILA in OSCC cells. Additionally, the role of NKILA in vitro was determined by inducing xenograft tumors in nude mice.

Results:

NKILA was poorly expressed in OSCC tissues and cells. Cell proliferation, invasion and migration, tumor volume and weight were significantly suppressed in cells with overexpressed NKILA, while silencing NKILA led to opposite trends. Moreover, the protein levels of p-IκBα and nuclear-p65 were markedly decreased, while the levels of IκBα and cytoplasm-p65 were enhanced in cells with overexpressed NKILA.

Conclusion:

This study provided evidence that NKILA could reduce proliferation, invasion and migration of OSCC cells through inhibiting the NF-κB signaling pathway. The findings may offer new insights for OSCC prevention and treatment.

Inhibition of microRNA-15b-5p Attenuates the Progression of Oral Squamous Cell Carcinoma via Modulating the PTPN4/STAT3 Axis

BACKGROUND

Emerging evidence has demonstrated the important functions of microRNAs (miRNAs) in human malignancies. This study focuses on the function of miR-15b-5p on the oral squamous cell carcinoma (OSCC) progression and the molecules involved.

METHODS

Tumor and the paracancerous tissues were obtained from OSCC patients. Differentially expressed miRNAs between the tumor and normal tissues were screened out. miR-15b-5p expression in tumors and acquired cells was determined, and its correlation with patient survival was analyzed. Knockdown of miR-15b-5p was introduced in SCC-4 and CAL-27 cells to explore its role in cell growth and metastasis. Binding relationship between miR-15b-5p and PTPN4 was validated, and altered expression of PTPN4 was introduced in cells to explore its function in OSCC development. Xenograft tumors were induced in nude mice for in vivo experiments.

RESULTS

miR-15b-5p was abundantly expressed in OSCC tumors and cells and linked to poor survival in patients. Silencing of miR-15b-5p suppressed proliferation, migration, and invasion and triggered apoptosis in SCC-4 and CAL-27 cells. miR-15b-5p targeted PTPN4. Further silencing of PTPN4 blocked the inhibiting functions of miR-15b-5p inhibitor in OSCC cell growth. The in vitro results were reproduced in vivo, where inhibition of miR-15b-5p led to a decline in tumor growth and metastasis in nude mice. PTPN4 was found as a negative mediator of the STAT3 pathway.

CONCLUSION

This study evidenced that miR-15b-5p possibly promotes OSCC development through binding to PTPN4 and the following STAT3 signaling activation. miR-15b-5p may be a potential therapeutic target for OSCC.

Development of lung metastases in mouse models of tongue squamous cell carcinoma

OBJECTIVE

Oral squamous cell carcinoma (OSCC) represents 3%-4% of all cancers. Despite the increasing incidence of OSCC distant metastasis and poor prognosis, few animal models of OSCC distant metastasis have been reported. In this study, we established mouse models of OSCC lung metastasis by orthotopic and tail vein injection of new OSCC cell lines.

METHODS

For the tail vein model, we used a novel cell line isolated from lung metastases reproduced in vivo after intravenous injection of HSC-3 GFP/luciferase cells and sorted for GFP expression (HSC-3 M1 GFP/luciferase). Lung metastases were assessed by imaging techniques and further confirmed by histology. For the orthotopic model, HSC-3 GFP/luciferase cells were injected into the tongue of athymic nude mice. The primary tumor and metastases were assessed by in vivo imaging, histology, and immunohistochemistry.

RESULTS

The orthotopic model presented spontaneous lung metastases in 50% of the animals and lymph node metastases were present in 83% of cases. In the tail vein model, a lung metastasis rate of 60% was observed.

CONCLUSIONS

Lung metastases were successfully reproduced by orthotopic and tail vein injection. Since lymph node metastases were present, the orthotopic model with HSC-3 GFP/luciferase cells may be suitable to investigate metastatic dissemination in OSCC.

Dietary fat and male sex increase histopathological changes in a mouse model of oral cancer

OBJECTIVE

To compare the effects of dietary fat and sex on murine oral squamous cell carcinoma pathology.

MATERIALS AND METHODS

Male and female C57Bl/6 mice (36/sex) received a low-fat (10 kcal%) or high-fat (60 kcal%) diet. Water (control), vehicle, or 4-nitroquinoline-1-oxide in vehicle (50 μg/ml) was provided for 17 weeks followed by six additional weeks of water. Oral lesion development was recorded weekly. Histopathologic changes in tongues were examined, and T cells (CD3+), macrophages (CD68+), and neutrophils (Ly6+) were quantified.

RESULTS

All 4-nitroquinoline-1-oxide-treated mice developed oral tumors. High-fat diet exacerbated pathology, demonstrated by an increased final tumor burden (10.9 ± 4.5 vs. 7.9 ± 2.5, mm/mouse, p < .05; high-fat diet vs. low-fat diet, respectively), and a greater histopathology score. When dietary groups were combined, 4-nitroquinoline-1-oxide-treated males displayed higher histopathology scores than females (4.2 ± 0.3 vs. 3.6 ± 0.2, respectively, p < .05). Lymphoid cell infiltration was greater in the 4-nitroquinoline-1-oxide mouse tongues than controls: T cells (14.0 vs. 0.96 cells/mm² ), macrophages (3.6 vs. 1.8 cells/mm² ), and neutrophils (12.0 vs. 0.38 cells/mm² ).

CONCLUSION

High-fat diet and male sex increased the pathology of 4-nitroquinoline-1-oxide-induced oral cancer. Elevated lymphoid cell infiltration contributed to disease pathology.

Profiling of Mitochondrial DNA Heteroplasmy in a Prospective Oral Squamous Cell Carcinoma Study

While a shift in energy metabolism is essential to cancers, the knowledge about the involvement of the mitochondrial genome in tumorigenesis and progression in oral squamous cell carcinoma (OSCC) is still very limited. In this study, we evaluated 37 OSCC tumors and the corresponding benign mucosa tissue pairs by deep sequencing of the complete mitochondrial DNA (mtDNA). After extensive quality control, we identified 287 variants, 137 in tumor and 150 in benign samples exceeding the 1% threshold. Variant heteroplasmy levels were significantly increased in cancer compared to benign tissues (p = 0.0002). Furthermore, pairwise high heteroplasmy frequency difference variants (∆HF% > 20) with potential functional impact were increased in the cancer tissues (p = 0.024). Fourteen mutations were identified in the protein-coding region, out of which thirteen were detected in cancer and only one in benign tissue. After eight years of follow-up, the risk of mortality was higher for patients who harbored at least one ∆HF% > 20 variant in mtDNA protein-coding regions relative to those with no mutations (HR = 4.6, (95%CI = 1.3-17); p = 0.019 in primary tumor carriers). Haplogroup affiliation showed an impact on survival time, which however needs confirmation in a larger study. In conclusion, we observed a significantly higher accumulation of somatic mutations in the cancer tissues associated with a worse prognosis.

A PIK3CA transgenic mouse model with chemical carcinogen exposure mimics human oral tongue tumorigenesis

Oral cancer causes significant global mortality and has a five-year survival rate of around 64%. Poor prognosis results from late-stage diagnosis, highlighting an important need to develop better approaches to detect oral premalignant lesions (OPLs) and identify which OPLs are at highest risk of progression to oral squamous cell carcinoma (OSCC). An appropriate animal model that reflects the genetic, histologic, immunologic, molecular and gross visual features of human OSCC would aid in the development and evaluation of early detection and risk assessment strategies. Here, we present an experimental PIK3CA + 4NQO transgenic mouse model of oral carcinogenesis that combines the PIK3CA oncogene mutation with oral exposure to the chemical carcinogen 4NQO, an alternate experimental transgenic mouse model with PIK3CA as well as E6 and E7 mutations, and an existing wild-type mouse model based on oral exposure to 4NQO alone. We compare changes in dorsal and ventral tongue gross visual appearance, histologic features and molecular biomarker expression over a time course of carcinogenesis. Both transgenic models exhibit cytological and architectural features of dysplasia that mimic human disease and exhibit slightly increased staining for Ki-67, a cell proliferation marker. The PIK3CA + 4NQO model additionally exhibits consistent lymphocytic infiltration, presents with prominent dorsal and ventral tongue tumours, and develops cancer quickly relative to the other models. Thus, the PIK3CA + 4NQO model recapitulates the multistep genetic model of human oral carcinogenesis and host immune response in carcinogen-induced tongue cancer, making it a useful resource for future OSCC studies.

A Mouse Model of Oropharyngeal Papillomavirus-Induced Neoplasia Using Novel Tools for Infection and Nasal Anesthesia

Human head and neck cancers that develop from the squamous cells of the oropharynx (Oropharyngeal Squamous Cell Carcinomas or OPSCC) are commonly associated with the papillomavirus infection. A papillomavirus infection-based mouse model of oropharyngeal tumorigenesis would be valuable for studying the development and treatment of these tumors. We have developed an efficient system using the mouse papillomavirus (MmuPV1) to generate dysplastic oropharyngeal lesions, including tumors, in the soft palate and the base of the tongue of two immune-deficient strains of mice. To maximize efficiency and safety during infection and endoscopy, we have designed a nose cone for isoflurane-induced anesthesia that takes advantage of a mouse’s need to breathe nasally and has a large window for oral manipulations. To reach and infect the oropharynx efficiently, we have repurposed the Greer Pick allergy testing device as a virus delivery tool. We show that the Pick can be used to infect the epithelium of the soft palate and the base of the tongue of mice directly, without prior scarification. The ability to induce and track oropharyngeal papillomavirus-induced tumors in the mouse, easily and robustly, will facilitate the study of oropharyngeal tumorigenesis and potential treatments.

Orthotopic tongue squamous cell carcinoma (SCC) model exhibiting a different tumor-infiltrating T-cell status with margin-restricted CD8+ T cells and regulatory T cell-dominance, compared to skin SCC

The immunological, and especially T cell, status of the tumor microenvironment affects tumor development and the efficacy of cancer treatment. To devise suitable combination therapies based on the results of murine tumor models, a more realistic orthotopic model is required. In this study, we generated a murine model of tongue squamous cell carcinoma (SCC), in which the tumor-immune cell interactions were recapitulated, and examined tumor- and T-cell status compared to a skin-transplanted SCC model by multiplex immunofluorescence staining for epidermal growth factor receptor, CD31, CD8, CD4, and Foxp3. Administration of SCCVII cells did not induce undesirable tissue damage or inflammation. In tongue SCC, abundant T-cell infiltration was observed at the tumor margin, but not in the core. Tongue SCC predominantly showed CD8⁺ T or Foxp3⁺ regulatory T cell (Treg)-infiltration. In contrast, skin-transplanted SCC showed abundant infiltration of T cells in the whole tumor area, which was dominated by Tregs. An orthotopic tongue SCC model showed differences in tumor and T-cell status compared to the skin-transplanted SCC model. Our tongue SCC model may enhance understanding of tumor-host interactions and enable evaluation of therapeutic efficacy.

The Hamster Model of Sequential Oral Carcinogenesis: An Update

Animal models are valuable tools for studying human cancer as well as for preclinical trials. The hamster model of chemically induced sequential oral carcinogenesis was developed by our group a decade ago in order to study the multistep process of alterations in gene expression during carcinogenesis. The purpose of this review was to discuss the utility of the hamster model of sequential oral carcinogenesis regarding the deciphering of the main pathways altered. An extended search for articles that cited that specific animal models was performed. Many studies have used the hamster model of sequential oral carcinogenesis either for evaluation of the expression of biomarkers alone, or for applying chemopreventive compounds and other therapeutic methods, or combining the use of biomarkers with the anticancer effect of some compounds. It seems that this animal model is indeed a useful tool that enables the study of cell biology, pathology and therapeutics of oral cancer.

The antilymphatic metastatic effect of hyaluronic acid in a mouse model of oral squamous cell carcinoma

Objectives: Lymphatic metastasis is the main cause of low patient survival in cases of oral squamous cell carcinoma (OSCC). Several animal models have been established to uncover the mechanism that regulates lymph node metastasis of OSCC cells. Unfortunately, these models often take a long time to establish. The prolonged tumor burden can lead to animal cachexia, which may ultimately affect the experimental outcome. To overcome the disadvantages of these models, we established an orthotopic metastatic animal model of OSCC that showed quick lymph node metastasis potential.Results: DiR dye-labeled CAL27 cells were injected into tongue tissues of BALB/c nude mice, and the cells metastasized to lymph nodes on day 3. Metastasis was monitored using an in vivo imaging system and confirmed by histological observation. Using this model, we investigated the role of hyaluronic acid (HA) on the cervical metastasis of OSCC cells. Surprisingly, we found that the presence of HA significantly reduced the incidence of metastasis to cervical lymph nodes compared with the control group. Further analysis revealed that the presence of exogenous HA promoted mesenchymal-epithelial transition (MET) in primary tumors while reducing the metastatic potential of OSCC.Conclusion: Our findings confirmed the establishment of a fast and reliable lymphatic metastatic mouse model of OSCC that can be used for investigating metastatic mechanisms and analyzing various antimetastasis strategies. An equally important discovery is the antimetastatic property of HA, which could provide a potential therapeutic strategy for OSCC.

DMBA-Induced Oral Carcinoma in Syrian Hamster: Increased Carcinogenic Effect by Dexamethasone Coexposition

Objectives

To investigate the effect of systemic administration of the immunosuppressant dexamethasone (DM) while inducing hamster buccal pouch DMBA carcinogenesis. Materials and Methods. Two different experiments were performed. In the first experiment, hamsters' right buccal pouches in group A (n = 10) were painted three times per week with 7,12-dimethylbenzanthracene (DMBA) 0.5%, while pouches of animals in group B (n = 10) were painted three times per week with 7,12-dimethylbenzanthracene (DMBA) 0.5%, while pouches of animals in group B (

Results

The time of macroscopic neoplasm development was reduced when DM-DMBA coexposition was employed, finding tumors after 10–12 weeks of exposition. In addition, the frequency of histopathological lesions was higher.

Conclusion

Immunomodulatory action of dexamethasone may reduce the time of oral squamous cell carcinoma (OSCC) induction and may increase the incidence of neoplasms developed.

Genipin Induces Autophagy and Suppresses Cell Growth of Oral Squamous Cell Carcinoma via PI3K/AKT/MTOR Pathway

Background

Oral squamous cell carcinoma (OSCC) is a common malignant tumor of the head and neck, and it accounts for more than 90% of oral cancer. Due to high mortality, limitations of traditional treatment and many complications, new treatment methods are urgently needed. This study aimed to look into the effect of new potential anti-tumor drug, genipin, on OSCC treatment.

Methods

In vitro, CCK-8, colony formation, and flow cytometry were used to detect the effect of genipin on SCC-9 and SCC-15 cell lines. Immunofluorescence, real-time PCR, and Western blotting were used to investigate its mechanism. Xenograft tumor model was used to explore the role of genipin in vivo.

Results

We found that genipin suppressed cell growth and induced apoptosis in vitro. In addition, the expression of p62 was down-regulated while Beclin1 and LC3II were up-regulated in SCC-25 and SCC-9 cells. 3-methyladenine (3-MA) significantly decreased LC3 (LC3II)⁺ puncta, but genipin rescuect 3d this reduction. Furthermore, genipin also reduced the expression of p-PI3K, p-AKT, and p-mTOR. In vivo experiment showed that genipin significantly curbed the tumor size and weight. The positive expression of Ki67 protein and number of apoptotic cells were increased.

Conclusion

Conclusively, this study implicated that genipin suppresses cell proliferation and stimulated apoptosis, and is the first exploration showing that genipin induces OSCC cell autophagy via PI3K/AKT/mTOR pathway inhibition.

Mouse Tumor-Bearing Models as Preclinical Study Platforms for Oral Squamous Cell Carcinoma

Preclinical animal models of oral squamous cell carcinoma (OSCC) have been extensively studied in recent years. Investigating the pathogenesis and potential therapeutic strategies of OSCC is required to further progress in this field, and a suitable research animal model that reflects the intricacies of cancer biology is crucial. Of the animal models established for the study of cancers, mouse tumor-bearing models are among the most popular and widely deployed for their high fertility, low cost, and molecular and physiological similarity to humans, as well as the ease of rearing experimental mice. Currently, the different methods of establishing OSCC mouse models can be divided into three categories: chemical carcinogen-induced, transplanted and genetically engineered mouse models. Each of these methods has unique advantages and limitations, and the appropriate application of these techniques in OSCC research deserves our attention. Therefore, this review comprehensively investigates and summarizes the tumorigenesis mechanisms, characteristics, establishment methods, and current applications of OSCC mouse models in published papers. The objective of this review is to provide foundations and considerations for choosing suitable model establishment methods to study the relevant pathogenesis, early diagnosis, and clinical treatment of OSCC.

HSPD1 repressed E-cadherin expression to promote cell invasion and migration for poor prognosis in oral squamous cell carcinoma

Buccal mucosa squamous cell carcinoma (BMSCC) is one of major subsites of oral cancer and is associated with a high rate of metastasis and poor prognosis. Heat shock proteins (HSPs) act as potential prognostic biomarkers in many cancer types. However, the role of HSPD1 in oral cancer, especially in BMSCC, is still unknown. Through data analysis with The Cancer Genome Atlas (TCGA), we found the association of HSPD1 gene expression with tumorigenesis and poor prognosis in oral cancer patients. Our cohort study showed that higher HSPD1 protein level was associated with tumorigenesis and poor prognosis in BMSCC patients with lymph node invasion, suggesting that HSPD1 may be involved in tumor metastasis. Moreover, knockdown of HSPD1 induced E-cadherin expression and decreased the migration and invasion of BMSCC cells. In contrast, ectopic expression of HSPD1 diminished E-cadherin expression and promoted the migration/invasion of BMSCC cells. Further, HSPD1 regulated RelA activation to repress E-cadherin expression, enhancing the migration and invasion of BMSCC cells. Furthermore, HSPD1 protein level was inversely correlated with E-cadherin protein level in tumor tissues and co-expression of high HSPD1/low E-cadherin showed a significant association with poor prognosis in BMSCC patients. Taken together, HSPD1 might repress E-cadherin expression and promote metastatic characters of BMSCC cells for poor prognosis of BMSCC patients.

Licochalcone A inhibits cell proliferation, migration, and invasion through regulating the PI3K/AKT signaling pathway in oral squamous cell carcinoma

Background: Oral squamous cell carcinoma (OSCC) is one of the most common cancers, with high metastasis and mortality. Licochalcone A (LCA) is a chalconoid from the root of Glycyrrhiza inflata, which has anti-tumor, anti-inflammatory, anti-angiogenesis effects in many cancers. However, the mechanism that underlies LCA regulating cell proliferation, migration, and invasion in OSCC remains poorly understood.

Methods: LY294002 or insulin-like growth factor 1 (IGF-1) were used to block or stimulate the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT) pathway in OSCC cells. Cell proliferation was investigated by MTT assay and proliferating cell nuclear antigen (PCNA) protein level using Western blot. The expression of metastasis-related protein was detected via Western blot. Cell migration and invasion abilities were evaluated by trans-well assay. A murine xenograft model of OSCC was established to investigate the anti-tumor effect of LCA in vivo.

Results: Treatment of LCA inhibited cell proliferation in SCC4 and CAL-27 cells. Moreover, PI3K/AKT signaling was blocked by LY294002, and activated by IGF-1. LCA could suppress proliferation, migration, and invasion of OSCC cells, which was similar to the treatment of LY294002. In addition, LCA decreased IGF-1-induced OSCC progression. In a murine xenograft model, LCA treatment protected against tumor growth and metastasis in vivo.

Conclusions: LCA might inhibit cell proliferation, migration, and invasion through regulating the PI3K/AKT pathway in OSCC, developing a potential chemotherapeutic agent for OSCC.