Precision Therapy of Head and Neck Squamous Cell Carcinoma

Advances in tumor immune microenvironment of head and neck squamous cell carcinoma: A review of literature

Squamous cell carcinoma is seen as principal malignancy of head and neck. Tumor immune microenvironment plays a vital role in the occurrence, development and treatment of head and neck squamous cell carcinoma (HNSCC). The effect of immunotherapy, in particular, is closely related to tumor immune microenvironment. This review searched for high-quality literature included within PubMed, Web of Science, and Scopus using the keywords "head and neck cancers," "tumor microenvironment" and "immunotherapy," with the view to summarizing the characteristics of HNSCC immune microenvironment and how various subsets of immune cells promote tumorigenesis. At the same time, based on the favorable prospects of immunotherapy having been shown currently, the study is committed to pinpointing the latest progress of HNSCC immunotherapy, which is of great significance in not only further guiding the diagnosis and treatment of HNSCC, but also conducting its prognostic judgement.

The Use of Immune Regulation in Treating Head and Neck Squamous Cell Carcinoma (HNSCC)

Immunotherapy has emerged as a promising new treatment modality for head and neck cancer, offering the potential for targeted and effective cancer management. Squamous cell carcinomas pose significant challenges due to their aggressive nature and limited treatment options. Conventional therapies such as surgery, radiation, and chemotherapy often have limited success rates and can have significant side effects. Immunotherapy harnesses the power of the immune system to recognize and eliminate cancer cells, and thus represents a novel approach with the potential to improve patient outcomes. In the management of head and neck squamous cell carcinoma (HNSCC), important contributions are made by immunotherapies, including adaptive cell therapy (ACT) and immune checkpoint inhibitor therapy. In this review, we are focusing on the latter. Immune checkpoint inhibitors target proteins such as programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) to enhance the immune response against cancer cells. The CTLA-4 inhibitors, such as ipilimumab and tremelimumab, have been approved for early-stage clinical trials and have shown promising outcomes in terms of tumor regression and durable responses in patients with advanced HNSCC. Thus, immune checkpoint inhibitor therapy holds promise in overcoming the limitations of conventional therapies. However, further research is needed to optimize treatment regimens, identify predictive biomarkers, and overcome potential resistance mechanisms. With ongoing advancements in immunotherapy, the future holds great potential for transforming the landscape of oral tumor treatment and providing new hope for patients.

AIM2 promotes irradiation resistance, migration ability and PD-L1 expression through STAT1/NF-κB activation in oral squamous cell carcinoma

BACKGROUND

Radioresistance and lymph node metastasis are common phenotypes of refractory oral squamous cell carcinoma (OSCC). As a result, understanding the mechanism for radioresistance and metastatic progression is urgently needed for the precise management of refractory OSCC. Recently, immunotherapies, e.g. immune checkpoint inhibitors (ICIs), were employed to treat refractory OSCC; however, the lack of predictive biomarkers still limited their therapeutic effectiveness.

METHODS

The Cancer Genome Atlas (TCGA)/Gene Expression Omnibus (GEO) databases and RT-PCR analysis were used to determine absent in melanoma 2 (AIM2) expression in OSCC samples. Colony-forming assay and trans-well cultivation was established for estimating AIM2 function in modulating the irradiation resistance and migration ability of OSCC cells, respectively. RT-PCR, Western blot and flow-cytometric analyses were performed to examine AIM2 effects on the expression of programmed death-ligand 1 (PD-L1) expression. Luciferase-based reporter assay and site-directed mutagenesis were employed to determine the transcriptional regulatory activity of Signal Transducer and Activator of Transcription 1 (STAT1) and NF-κB towards the AIM2-triggered PD-L1 expression.

RESULTS

Here, we found that AIM2 is extensively upregulated in primary tumors compared to the normal adjacent tissues and acts as a poor prognostic marker in OSCC. AIM2 knockdown mitigated, but overexpression promoted, radioresistance, migration and PD-L1 expression via modulating the activity of STAT1/NF-κB in OSCC cell variants. AIM2 upregulation significantly predicted a favorable response in patients receiving ICI treatments.

CONCLUSIONS

Our data unveil AIM2 as a critical factor for promoting radioresistance, metastasis and PD-L1 expression and as a potential biomarker for predicting ICI effectiveness on the refractory OSCC.

Advantages of the Combinatorial Molecular Targeted Therapy of Head and Neck Cancer-A Step before Anakoinosis-Based Personalized Treatment

The molecular initiators of Head and Heck Squamous Cell Carcinoma (HNSCC) are complex. Human Papillomavirus (HPV) infection is linked to an increasing number of HNSCC cases, but HPV-positive tumors generally have a good prognosis. External factors that promote the development of HPV-negative HNSCC include tobacco use, excessive alcohol consumption, and proinflammatory poor oral hygiene. On a molecular level, several events, including the well-known overexpression of epidermal growth factor receptors (EGFR) and related downstream signaling pathways, contribute to the development of HNSCC. Conventional chemotherapy is insufficient for many patients. Thus, molecular-based therapy for HNSCC offers patients a better chance at a cure. The first molecular target for therapy of HNSCC was EGFR, inhibited by monoclonal antibody cetuximab, but its use in monotherapy is insufficient and induces resistance. This article describes attempts at combinatorial molecular targeted therapy of HNSCC based on several molecular targets and exemplary drugs/drug candidates. The new concept of anakoinosis-based therapy, which means treatment that targets the intercellular and intracellular communication of cancer cells, is thought to be the way to improve the clinical outcome for HNSCC patients. The identification of a link between molecular targeted therapy and anakoinosis raises the potential for further progress in HPV-negative HNSCC therapy.

miR-30e-5p-mediated FOXD1 promotes cell proliferation by blocking cellular senescence and apoptosis through p21/CDK2/Rb signaling in head and neck carcinoma

Forkhead box D1 (FOXD1) belongs to the FOX protein family, which has been found to function as a oncogene in multiple cancer types, but its role in head and neck squamous cell carcinoma (HNSCC) requires further investigation. Our research aimed to investigate the function of FOXD1 in HNSCC. Bioinformatics analysis indicated that mRNA level of FOXD1 was highly expressed in HNSCC tissues, and over-expressed FOXD1 was related to poor prognosis. Moreover, FOXD1 knockdown increased the ratio of senescent cells but decreased the proliferation ability, while FOXD1 overexpression obtained the opposite results. In vitro experiments revealed that FOXD1 bound to the p21 promoter and inhibited its transcription, which blocked the cyclin dependent kinase 2 (CDK2)/retinoblastoma (Rb) signaling pathway, thus preventing senescence and accelerating proliferation of tumor cells. CDK2 inhibitor could reverse the process to some extent. Further research has shown that miR-3oe-5p serves as a tumor suppressant by repressing the translation of FOXD1 through combining with the 3'-untranslated region (UTR). Thus, FOXD1 resists cellular senescence and facilitates HNSCC cell proliferation by affecting the expression of p21/CDK2/Rb signaling, suggesting that FOXD1 may be a potential curative target for HNSCC.

Diagnostic, Prognostic, and Therapeutic Role for Angiogenesis Markers in Head and Neck Squamous Cell Carcinoma: A Narrative Review

Despite refinements to diagnostic and therapeutic approaches over the last two decades, the outcome of patients with head and neck squamous cell carcinoma (HNSCC) has not shown substantial improvements, especially regarding those with advanced-stage disease. Angiogenesis is believed to be a turning point in the development of solid tumors, being a premise for mass growth and potential distant dissemination. Cancer-induced angiogenesis is a result of increased expression of angiogenic factors, decreased expression of anti-angiogenic factors, or a combination of both. The assessment of angiogenesis has also emerged as a potentially useful biological prognostic and predictive factor in HNSCC. The aim of this review is to assess the level of current knowledge on the neo-angiogenesis markers involved in the biology, behavior, and prognosis of HNSCC. A search (between 1 January 2012 and 10 October 2022) was run in PubMed, Scopus, and Web of Science electronic databases. After full-text screening and application of inclusion/exclusion criteria, 84 articles are included. The current knowledge and debate on angiogenesis in HNSCC presented in the eligible articles are stratified as follows: (i) diagnostic markers; (ii) prognostic markers; (iii) predictive markers; and (iv) markers with a potential therapeutic role. Angiogenesis is a biological and pathological indicator of malignancies progression and has negative implications in prognosis of some solid tumors; several signals capable of tripping the "angiogenic switch" have also been identified in HNSCC. Although several studies suggested that antiangiogenic agents might be a valuable adjunct to conventional chemo-radiation of HNSCC, their long-term therapeutic value remains uncertain. Further investigations are required on combinations of antiangiogenic agents with conventional chemotherapeutic ones, immunotherapeutic and molecularly targeted agents in HNSCC. Additional data are necessary to pinpoint which patients could benefit most from these treatments.

Preoperative anemia: Predictor of free flap reconstruction complications in head and neck cancer

Free flap reconstruction has been the mainstay among reconstruction surgeries for head and neck cancer. Intraoperative and postoperative hemoglobin (Hb) levels were both possible risk factors of flap failure and had been discussed widely. However, few investigations of preoperative Hb were seen in the previous study with its effect to flap condition remain uncertain and no conclusions in the literature. Patients who underwent free flap reconstruction after head and neck surgery in our institution between May 2014 and May 2019 were enrolled. The postoperative flap condition was observed carefully, and re-exploration was performed if necessary. We then retrospectively collected patient data with several intraoperative and postoperative indices. A total of 598 patients were enrolled in our study. The total major flap complication rate was 10.6%, with an overall success rate of 89.4%. They were predominantly male (95%), and most of them underwent free flap reconstruction for the first time (91%). A total of 81 (13%) patients received radiotherapy before reconstruction. Among all factors, the preoperative Hb level and free flap type showed significance in univariate and multivariate analyses. A previous history of radiotherapy, body mass index, nutrition status, or poorly controlled diabetes mellitus showed no significant results in either univariate or multivariate analysis. Our study showed that a lower preoperative Hb level affects free flap survival. Meanwhile, preoperative radiotherapy history has no significant influence in either univariate or multivariate analysis.

Therapeutic Targeting of MYC in Head and Neck Squamous Cell Carcinoma

MYC plays critical roles in tumorigenesis and is considered an attractive cancer therapeutic target. Small molecules that directly target MYC and are well tolerated in vivo represent invaluable anti-cancer therapeutic agents. Here, we aimed to investigate the therapeutic effect of MYC inhibitors in head and neck squamous cell carcinoma (HNSCC). The results showed that pharmacological and genetic inhibition of MYC inhibited HNSCC proliferation and migration. MYC inhibitor 975 (MYCi975), inhibited HNSCC growth in both cell line-derived xenograft and syngeneic murine models. MYC inhibition also induced tumor cell-intrinsic immune responses, and promoted CD8⁺ T cell infiltration. Mechanistically, MYC inhibition increased CD8⁺ T cell-recruiting chemokines by inducing the DNA damage related cGAS-STING pathway. High expression of MYC combined with a low level of infiltrated CD8⁺ T cell in HNSCC correlated with poor prognosis. These results suggested the potential of small-molecule MYC inhibitors as anti-cancer therapeutic agents in HNSCC.

Comparison of PD-L1 Expression in Oral Squamous Cell Carcinoma and Premalignant Lesions of Oral Cavity

OBJECTIVE

Objectives of this study were to compare  expression of Programmed Death-Ligand 1(PD-L1) protein in oral squamous cell carcinoma (OSCC) and oral potentially malignant disorder (OPMD) cases; and to compare the PD-L1 protein expression in histological grades of OSCC and also in OPMD's with Dysplasia and without Dysplasia.

MATERIALS & METHODS

In this study,  25 cases of Oral squamous cell carcinoms, 25 cases of Oral Potentially Malignant Disorders and 10 cases of non-neoplastic oral mucosa (control) cases were included. FFPE blocks of OSCC and OPMD cases were contributed by Department of Pathology, Histopathology Division,Pakistan Institute of Medical Sciences, Islamabad. Immunohistochemical staining of cases with PD-L1 monoclonal antibody (1:100; Dako) was carried out at Histopathology division , PMC Labs,  Peshawar Medical College,Peshawar, Riphah International University, Islamabad . Epithelial cells (membranous and cytoplasmic) positivity was observed for PD-L1 Antibody. Data was analyzed in SPSS version20. For qualitative variables frequencies and percentages were calculated whereas for quantitative variables means and standard deviations were recorded. The Chi-square test was applied to evaluate the significant difference in categorical variables . p-value of ≤0.05 was taken as significant.

RESULTS

PD-L1 expression in OSCC cases turned out to be 48% (n=12/25) as compared to 8% of OPMD cases (n=2/25) with a significant p value of 0.002 and all non-neoplastic oral mucosa cases were negative. PD-L1 expression in high grade OSCC cases was quite high (61% n=11/18) as compared to low grade OSCC (14% n=1/7) cases with a significant p value of 0.035.

CONCLUSION

A statistically significant increased PD-L1 expression was noted in  OSCC as compared to OPMD. Expression of PD-L1 was more intense in high grade OSCC cases. The relation of PD-L1 expression to age ,gender or location of OSCC and OPMD cases , and presence of dysplasia in OPMD cases was statistically not significant.

Relationships of Ferroptosis and Pyroptosis-Related Genes with Clinical Prognosis and Tumor Immune Microenvironment in Head and Neck Squamous Cell Carcinoma

Ferroptosis and pyroptosis are two new programmed cell death (PCD) modes discovered in recent years. However, the potential value of ferroptosis and pyroptosis-related genes (FPRGs) in prognosis prediction and the tumor immune microenvironment of head and neck squamous cell carcinoma (HNSCC) is still unclear. We obtained 21 significant FPRGs based on the training dataset (TCGA- HNSC) using the univariate Cox and differential expression analysis. The TCGA- HNSC (n = 502) dataset was clustered into two group (clusters A and B) based on the 21 significant FPRGs. 1467 differentially expressed genes (DEGs) between cluster A and B were put into univariate Cox and Least absolute shrinkage and selection operator (LASSO) analysis to build a risk model. The predictive capability of the risk model was successfully confirmed by internal validation, external validation, and clinical sample validation. To improve the clinical applicability, a nomogram model combined risk score and clinical information were constructed. Moreover, the patients with lower risk score were characterized by increased immune response and tumor mutation burden (TMB), while the patients with higher risk score were characterized by increased TP53 mutation rate. In conclusion, our comprehensive analysis of the FPRGs revealed their significant role in prognosis prediction and the tumor immune microenvironment. The risk model containing 9 FPRGs could be a potential prognostic markers and effective immunotherapy targets for HNSCC.

Comprehensive Analysis of mTORC1 Signaling Pathway–Related Genes in the Prognosis of HNSCC and the Response to Chemotherapy and Immunotherapy

Objective: The mammalian target of the rapamycin complex 1 (mTORC1) signaling pathway has emerged as a crucial player in the oncogenesis and development of head and neck squamous cell carcinoma (HNSCC), however, to date, no relevant gene signature has been identified. Therefore, we aimed to construct a novel gene signature based on the mTORC1 pathway for predicting the outcomes of patients with HNSCC and their response to treatment.

Methods: The gene expression and clinical data were retrieved from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. The key prognostic genes associated with the mTORC1 pathway were screened by univariate Cox regression analyses. A prognostic signature was then established based on significant factors identified in the multivariate Cox regression analysis. The performance of the multigene signature was evaluated by the Kaplan–Meier (K–M) survival analysis and receiver operating characteristic (ROC) analysis. Based on the median risk score, patients were categorized into high- and low-risk groups. Subsequently, a hybrid prognostic nomogram was constructed and estimated by a calibration plot and decision curve analysis. Furthermore, immune cell infiltration and therapeutic responses were compared between the two risk groups. Finally, we measured the expression levels of seven genes by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC).

Results: The mTORC1 pathway–based signature was constructed using the seven identified genes (SEC11A, CYB5B, HPRT1, SLC2A3, SC5D, CORO1A, and PIK3R3). Patients in the high-risk group exhibited a lower overall survival (OS) rate than those in the low-risk group in both datasets. Through the univariate and multivariate Cox regression analyses, this gene signature was confirmed to be an independent prognostic risk factor for HNSCC. The constructed nomogram based on age, American Joint Committee on Cancer (AJCC) stage, and the risk score exhibited satisfactory performance in predicting the OS. In addition, immune cell infiltration and chemotherapeutic and immunotherapeutic responses differed significantly between the two risk groups. The expression levels of SEC11A and CYB5B were higher in HNSCC tissues than in normal tissues.

Conclusion: Our study established and verified an mTORC1 signaling pathway–related gene signature that could be used as a novel prognostic factor for HNSCC.

Current and Emerging Molecular Therapies for Head and Neck Squamous Cell Carcinoma

Head and neck cancer affects nearly 750,000 patients, with more than 300,000 deaths annually. Advances in first line surgical treatment have improved survival rates marginally particularly in developed countries, however survival rates for aggressive locally advanced head and neck cancer are still poor. Recurrent and metastatic disease remains a significant problem for patients and the health system. As our knowledge of the genomic landscape of the head and neck cancers continues to expand, there are promising developments occurring in molecular therapies available for advanced or recalcitrant disease. The concept of precision medicine is underpinned by our ability to accurately sequence tumour samples to best understand individual patient genomic variations and to tailor targeted therapy for them based on such molecular profiling. Not only is their purported response to therapy a factor of their genomic variation, but so is their inclusion in biomarker-driven personalised medicine therapeutic trials. With the ever-expanding number of molecular druggable targets explored through advances in next generation sequencing, the number of clinical trials assessing these targets has significantly increased over recent years. Although some trials are focussed on first-line therapeutic approaches, a greater majority are focussed on locally advanced, recurrent or metastatic disease. Similarly, although single agent monotherapy has been found effective in some cases, it is the combination of drugs targeting different signalling pathways that seem to be more beneficial to patients. This paper outlines current and emerging molecular therapies for head and neck cancer, and updates readers on outcomes of the most pertinent clinical trials in this area while also summarising ongoing efforts to bring more molecular therapies into clinical practice.

EPHB4 Regulates the Proliferation and Metastasis of Oral Squamous Cell Carcinoma through the HMGB1/NF-κB Signalling Pathway

Background: Malignant proliferation and cervical lymphatic metastasis restrict the prognosis of oral squamous cell carcinoma (OSCC). Erythropoietin-producing human hepatocellular B4 (EPHB4) regulates a series of tumour functions involving tumourigenesis, cancer cell attachment and metastasis. However, the mechanism of EphB4 regulating the malignant progression of OSCC has not been fully elucidated. Methods: EPHB4 expression was analysed in 65 OSCC samples and adjacent noncancerous tissues through immunohistochemistry (IHC). siRNA and overexpression plasmids were transfected into OSCC cells to modify EPHB4 expression, and then, regulatory functions were explored in vitro and in vivo. Co-immunoprecipitation (Co-IP) and mass spectrometry were applied to detect proteins interacting with EPHB4. Subsequently, protein stability assays and NF-κB pathway inhibition assays were used to verify the regulation of EPHB4, high-mobility group box 1 (HMGB1) and nuclear factor-κB (NF-κB) activation. Results: EPHB4 was found to be highly expressed in OSCC tissues, which was related to tumour stage and lymphatic metastasis and resulted in a poor prognosis. Cellular experiments and mouse tongue xenograft models further confirmed that high EPHB4 expression promoted the proliferation and metastasis of OSCC tumours. Mechanistically, co-IP and mass spectrometry studies indicated that EPHB4 could bind to HMGB1 and maintain HMGB1 stability. Downregulation of HMGB1 inhibited the proliferation and metastasis of OSCC cells and inhibited NF-κB phosphorylation activation but did not affect EPHB4 expression. Conclusion: This study revealed the mechanism by which EPHB4 promotes the proliferation and metastasis of OSCC by activating the HMGB1-mediated NF-κB signalling pathway, which can be exploited as a novel marker or therapeutic target to control metastasis and improve the survival rate of OSCC.

The Role of Immunotherapy to Overcome Resistance in Viral-Associated Head and Neck Cancer

A subset of head and neck cancers arising in the oropharynx and the nasopharynx are associated with human papillomavirus or Epstein-Barr virus. Unfortunately, limited treatment options exist once patients develop recurrent or metastatic disease in these cancers. Interest has risen in utilizing novel strategies including combination immune checkpoint inhibitors, vaccines, and adoptive cellular therapy, to improve treatment response and outcomes. Several ongoing studies are investigating the potential to overcome resistance to standard of care chemoradiation therapy with monotherapy or combination immunotherapy strategies in these viral-associated head and neck cancers.

circFAT1 Promotes Cancer Stemness and Immune Evasion by Promoting STAT3 Activation

Cancer stemness and immune evasion are closely associated, and play critical roles in tumor development and resistance to immunotherapy. However, little is known about the underlying molecular mechanisms that coordinate this association. Here, it is reported that elevated circular RNA FAT1 (circFAT1) in squamous cell carcinoma (SCC) unifies and regulates the positive association between cancer stemness and immune evasion by promoting STAT3 activation. circFAT1 knockdown (KD) reduces tumorsphere formation of SCC cells in vitro and tumor growth in vivo. Bioinformatic analysis reveals that circFAT1 KD impairs the cancer stemness signature and activates tumor cell-intrinsic immunity. Mechanistically, circFAT1 binding to STAT3 in the cytoplasm prevents STAT3 dephosphorylation by SHP1 and promotes STAT3 activation, resulting in inhibition of STAT1-mediated transcription. Moreover, circFAT1 KD significantly enhances PD1 blockade immunotherapy by promoting CD8+ cell infiltration into tumor microenvironment. Taken together, the results demonstrate that circFAT1 is an important regulator of cancer stemness and antitumor immunity.

The functions of autophagy at the tumour-immune interface

Autophagy is frequently induced in the hypoxic tumour microenvironment. Accumulating evidence reveals important functions of autophagy at the tumour-immune interface. Herein, we propose an update on the roles of autophagy in modulating tumour immunity. Autophagy promotes adaptive resistance of established tumours to the cytotoxic effects of natural killer cells (NKs), macrophages and effector T cells. Increased autophagic flux in tumours dampen their immunogenicity and inhibits the expansion of cytotoxic T lymphocytes (CTLs) by suppressing the activation of STING type I interferon signalling (IFN-I) innate immune sensing pathway. Autophagy in suppressive tumour-infiltrating immune subsets maintains their survival through metabolic remodelling. On the other hand, autophagy is involved in the antigen processing and presentation process, which is essential for anti-tumour immune responses. Genetic deletion of autophagy induces spontaneous tumours in some models. Thus, the role of autophagy is context-dependent. In summary, our review has revealed the dichotomous roles of autophagy in modulating tumour immunity. Broad targeting of autophagy may not yield maximal benefits. The characterization of specific genes regulating tumour immunogenicity and innovation in targeted delivery of autophagy inhibitors into certain tumours are among the most urgent tasks to sensitize cold cancers to immunotherapy.

New Insights into Oral Cancer-Risk Factors and Prevention: A Review of Literature

The oral cancer constitutes 48% of head and neck cancer cases. Ninety percent of oral cancer cases are histologically diagnosed as oral squamous cell carcinomas (OSCCs). Despite new management strategies, the 5-year survival rate of oral cancer is still below 50% in most countries. Head and neck cancers are heterogeneous tumors, and this characteristic of them provides a challenge to treatment plan. Due to the poor outcomes in oral cancer, prevention is a necessity. In this review, a relevant English Literature search in PubMed, ScienceDirect, and Google Scholar from 2000 to mid-2018 was performed. All published articles related to oral cancer and its prevention were included. The risk factors of oral cancer and strategies of oral cancer prevention will be discussed.

Metformin as a senostatic drug enhances the anticancer efficacy of CDK4/6 inhibitor in head and neck squamous cell carcinoma

CDK4/6 inhibitors show promising antitumor activity in a variety of solid tumors; however, their role in head and neck squamous cell carcinoma (HNSCC) requires further investigation. The senescence-associated secretory phenotype (SASP) induced by CDK4/6 inhibitors has dual effects on cancer treatment. The need to address the SASP is a serious challenge in the clinical application of CDK4/6 inhibitors. We investigated whether metformin can act as a senostatic drug to modulate the SASP and enhance the anticancer efficacy of CDK4/6 inhibitors in HNSCC. In this study, the efficacy of a combination of the CDK4/6 inhibitor LY2835219 and metformin in HNSCC was investigated in in vitro assays, an HSC6 xenograft model, and a patient-derived xenograft model. Senescence-associated β-galactosidase staining, antibody array, sphere-forming assay, and in vivo tumorigenesis assay were used to detect the impacts of metformin on the senescence and SASP induced by LY2835219. We found that LY2835219 combined with metformin synergistically inhibited HNSCC by inducing cell cycle arrest in vitro and in vivo. Metformin significantly modulated the profiles of the SASP elicited by LY2835219 by inhibiting the mTOR and stat3 pathways. The LY2835219-induced SASP resulted in upregulation of cancer stemness, while this phenomenon can be attenuated when combined with metformin. Furthermore, results showed that the stemness inhibition by metformin was associated with blockade of the IL6-stat3 axis. Survival analysis demonstrated that overexpression of IL6 and stemness markers was associated with poor survival in HNSCC patients, indicating that including metformin to target these proteins might improve patient prognosis. Collectively, our data suggest that metformin can act as a senostatic drug to enhance the anticancer efficacy of CDK4/6 inhibitors by reprogramming the profiles of the SASP.

Evaluation Challenges in the Validation of B7-H3 as Oral Tongue Cancer Prognosticator

B7-H3 was the only molecule identified with prognostic potential from a recent systematic review of the prognostic value of immune checkpoints in oral cancer. We aimed to validate this finding in a multicenter international cohort. We retrospectively retrieved 323 oral tongue squamous cell carcinoma (OTSCC) samples from three different countries (Brazil, Finland, and Norway) for immunostaining and scoring for B7-H3. We evaluated tumor immunogenicity by analyzing the amount of tumor-infiltrating lymphocytes and divided the tumors into immune hot and cold. To increase the reliability of the results, both digital and manual visual scoring were used. Survival curves were constructed based on the Kaplan-Meier method, and the Cox proportional hazard model was utilized for univariate and multivariate survival analysis. B7-H3 expression was not significantly associated with overall or disease-specific survival in the whole OTSCC cohort. When divided into immune hot and cold tumors, high B7-H3 expression was significantly associated with poor disease-specific and overall survival in the immune hot group, depending on the scoring method and the country of the cohort. This was achieved only in the univariate analysis. In conclusion, B7-H3 was a negative prognosticator for OTSCC patient survival in the subgroup of immune hot tumors, and was not validated as a prognosticator in the full cohort. Our findings suggest that the immune activity of the tumor should be considered when testing immune checkpoints as biomarkers.

BMI1 Inhibition Eliminates Residual Cancer Stem Cells after PD1 Blockade and Activates Antitumor Immunity to Prevent Metastasis and Relapse

PD1 blockade-based combination therapy has been approved as a first-line treatment for head and neck squamous cell carcinoma (HNSCC). However, the response rate remains relatively low, and patients with HNSCC eventually relapse. Here, we show that the combination treatment of anti-PD1 and cisplatin enriched BMI1⁺ CSCs in HNSCC while inhibiting HNSCC growth. In contrast, the pharmacological and genetic inhibition of BMI1 eliminated BMI1⁺ CSCs and enabled PD1 blockade therapy, resulting in the inhibition of metastatic HNSCC and prevention of HNSCC relapses. BMI1 inhibition strongly induced tumor cell-intrinsic immune responses by recruiting and activating CD8⁺ T cells in addition to eliminating BMI1⁺ CSCs. Mechanistically, BMI1 inhibition induced CD8⁺ T cell-recruiting chemokines by stimulating IRF3-mediated transcription and erasing repressive H2A ubiquitination. Our results suggest that targeting BMI1 may enable immune checkpoint blockade to inhibit metastatic tumor growth and prevent tumor relapse by activating cell-intrinsic immunity, in addition to purging CSCs.

Adenovirus-mediated overexpression of interleukin-21 regulates the development of oral squamous cell carcinoma in vitro

Interleukin-21 (IL-21) is an important cytokine that is currently being investigated for its potential use in tumor immunotherapy in the future. In tumor cells, IL-21 stimulates the immune response by increasing the cytotoxic activity of natural killer cells, B cells and CD8⁺ T cells, which in turn induces the apoptosis of tumor cells. The therapeutic effects of IL-21 have been investigated in several types of disease and numerous clinical trials are in progress. The aim of the present study was to determine the role of IL-21 in oral squamous cell carcinoma (OSCC) in vitro. IL-21 expression was detected in OSCC tissues via RT-qPCR, western blotting and immunohistochemistry analyses. The results demonstrated that IL-21 protein expression decreased in OSCC tissues. IL-21 was overexpressed using adenovirus in CAL-27 cells. The Cell Counting Kit-8 assay demonstrated that overexpression of IL-21 inhibited cell proliferation. Furthermore, overexpression of IL-21 inhibited cell migration, detected by the wound healing assay, and promoted cell apoptosis, detected by TUNEL staining and flow cytometry analysis. The results demonstrated that overexpression of IL-21 inhibited activation of the JNK signaling pathway. In conclusion, the findings of the present study suggest that IL-21 may function as a potent antitumor agent in OSCC.

Clinicopathological Features of Programmed Cell Death-ligand 1 Expression in Patients with Oral Squamous Cell Carcinoma

Objective

Programmed cell death-ligand 1 (PD-L1) expression has been shown to play important roles in various types of cancer. However, the role of PD-L1 expression has not been conclusively reported in patients with oral squamous cell carcinoma (OSCC). Accordingly, in this meta-analysis, we investigated the clinicopathological value of PD-L1 expression in patients with OSCC.

Methods

Google Scholar, PubMed, EMBASE, and CNKI databases were searched to find relevant studies published through to September 16, 2019. The relationships between PD-L1 expression in patients with OSCC and clinicopathological features were assessed using risk ratio (RR) and 95% confidence intervals (CIs).

Results

Sixteen studies including 1989 participants were included. The results indicated that high PD-L1 expression was correlated with sex (RR = 1.28, 95% CI: 1.16-1.42, P < 0.001), N stage (RR = 1.19, 95% CI: 1.06-1.33, P = 0.003), M stage (RR = 1.64, 95% CI: 1.01-2.66, P = 0.044), low differentiation (RR = 1.16, 95% CI: 1.01-1.33, P = 0.034), and human papilloma virus infection (RR = 1.38, 95% CI: 1.14-1.68, P = 0.001), but unrelated to TNM stage or T stage. There was no significant publication bias in the studies included in this analysis.

Conclusions

This meta-analysis revealed that high PD-L1 expression in patients with OSCC was correlated with clinicopathological features. Further large-scale studies are necessary to confirm our results.

Immunoregulatory Potential of Exosomes Derived from Cancer Stem Cells

Head and neck squamous cell carcinomas (HNSCCs) are malignancies that originate in the mucosal lining of the upper aerodigestive tract. Despite advances in therapeutic interventions, survival rates among HNSCC patients have remained static for years. Cancer stem cells (CSCs) are tumor-initiating cells that are highly resistant to treatment, and are hypothesized to contribute to a significant fraction of tumor recurrences. Consequently, further investigations of how CSCs mediate recurrence may provide insights into novel druggable targets. A key element of recurrence involves the tumor's ability to evade immunosurveillance. Recent published reports suggest that CSCs possess immunosuppressive properties, however, the underlying mechanism have yet to be fully elucidated. To date, most groups have focused on the role of CSC-derived secretory proteins, such as cytokines and growth factors. Here, we review the established immunoregulatory role of exosomes derived from mixed tumor cell populations, and propose further study of CSC-derived exosomes may be warranted. Such studies may yield novel insights into new druggable targets, or lay the foundation for future exosome-based diagnostics.

Oral Rehabilitation of Patients Sustaining Orofacial Injuries: The UPenn Initiative

Tissue injuries in the oral and maxillofacial structures secondary to trauma, warfare, ablative cancer, and benign tumor surgery result in significant losses of speech, masticatory and swallowing functions, aesthetic deformities, and overall psychological stressors and compromise. Optimal oral rehabilitation remains a formidable challenge and an unmet clinical need due to the influence of multiple factors related to the physiologic limitations of tissue repair, the lack of site and function-specific donor tissues and constructs, and an integrated team of multidisciplinary professionals. The advancements in stem cell biology, biomaterial science, and tissue engineering technologies, particularly the 3-dimensional bioprinting technology, together with digital imaging and computer-aided design and manufacturing technologies, have paved the path for personalized/precision regenerative medicine. At the University of Pennsylvania, we have launched the initiative to integrate multidisciplinary health professionals and translational/clinical scientists in medicine, dentistry, stem cell biology, tissue engineering, and regenerative medicine to develop a comprehensive, patient-centered approach for precision and personalized reconstruction, as well as oral rehabilitation of patients sustaining orofacial tissue injuries and defects, especially oral cancer patients.

Tumor-related leukocytosis predictive of recurrence and survival in patients with oral cavity squamous cell carcinoma

OBJECTIVE

To evaluate the prognostic values of tumor-related leukocytosis (TRL) as a reliable biomarker predictive of recurrence and survival after definitive surgery for oral cavity squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

This retrospective study involved 322 patients who underwent tumor extirpation combined with neck dissection for treatment-naïve OSCC between 2006 and 2014. Multivariate binary logistic regression analyses were used to analyze the relationship between TRL and pathological variables. Cox proportional hazard regression analyses were used to find associations between factors and disease-free survival (DFS) or overall survival (OS).

RESULTS

TRL was significantly related to advanced disease status, tumor size, invasion depth, poor differentiation, and T and N classifications, resulting in increased post-treatment recurrence rate, particularly in the distant site. Multivariate logistic regression analyses showed that only the T classification was significantly associated with baseline TRL (p = 0.018). Multivariate analyses also showed that the tumor depth of invasion, pathological N classification, extranodal extension, and TRL remained the independent variables predictive of DFS and OS (all p < 0.05). TRL was related to a more than twofold increased risk of post-treatment recurrence and mortality.

CONCLUSIONS

TRL is associated with advanced tumor disease and increased recurrence and mortality in OSCC patients.

Knockdown of lncRNA LEF1-AS1 inhibited the progression of oral squamous cell carcinoma (OSCC) via Hippo signaling pathway

It is verified that long non-coding RNAs (lncRNAs) play crucial roles in various cancers. LncRNA LEF1-AS1 is a reported oncogene in colorectal cancer and glioblastoma. In this study, we unveiled that LEF1-AS1 markedly increased in oral squamous cell carcinoma (OSCC) tissues and cell lines. Besides, OSCC patients with high levels of LEF1-AS1 were apt to poor prognosis. Functionally, LEF1-AS1 knockdown inhibited cell survival, proliferation and migration, whereas enhanced cell apoptosis and induced G0/G1 cell cycle arrest in vitro. Consistently, LEF1-AS1 silence hindered tumor growth in vivo. Moreover, LEF1-AS1 inhibition stimulated the activation of Hippo signaling pathway through directly interacting with LATS1. Furtherly, we disclosed that LEF1-AS1 silence abolished the interaction of LEF1-AS1 with LATS1 while enhanced the binding of LATS1 to MOB, therefore promoting YAP phosphorylation but impairing YAP1 nuclear translocation. Additionally, we demonstrated that LEF1-AS1 regulated YAP1 translocation via a LATS1-dependent manner. Furthermore, we also uncovered that YAP1 overexpression abolished the suppressive impact of LEF1-AS1 repression on the biological processes of OSCC cells. In a word, we concluded that LEF1-AS1 served an oncogenic part in OSCC through suppressing Hippo signaling pathway by interacting with LATS1, suggesting the therapeutic and prognostic potential of LEF1-AS1 in OSCC.

Anti-tumor immunity induced by ectopic expression of viral antigens is transient and limited by immune escape

Immunotherapeutic treatments in head and neck cancer clinical trials include cancer vaccines targeting foreign viral antigens or mutational neoantigens derived from cancer-expressed proteins. Anti-tumor immune responses place cancer cells under selective pressure to lose or downregulate target antigens; therefore, vaccination against virus- or host- "driver" oncogenes are proposed as a strategy to overcome immune escape. Herein, we demonstrate the impact of immunogenic viral antigens on anti-tumor response and immune editing in MOC2-E6E7, a syngeneic murine oral cancer cell line expressing HPV-16 E6 and E7 oncoproteins. Using orthotopic syngeneic models, we observed in vivo tumor growth kinetics of MOC2-E6E7 is delayed in immunocompetent mice compared to parental MOC2 tumors. In contrast, tumor growth remained similar in Rag1^-/- mice lacking adaptive immunity. MOC2-E6E7 tumors demonstrated an "inflamed" or immune-activated tumor microenvironment and greater infiltration of CD8⁺ T cells compared to MOC2. By real-time PCR, we detected downregulation of E6 and E7 genes in MOC2-E6E7 tumors only in immunocompetent mice, suggesting the loss of ectopic viral antigen expression due to immune editing. We then assessed the efficacy of a biomaterials-based mesoporous silica rod (MSR) cancer vaccine targeting HPV-16 E7 in our model. Vaccination induced robust infiltration of antigen-specific CD8⁺ T cells, which led to tumor growth delay and modestly prolonged survival in MOC2-E6E7 tumors. Increased efficacy was seen in a separate head and neck cancer tumor model, mEER, which obligately expresses E7 antigen. Collectively, our data highlight the need for both immunogenicity and 'driver' status of target antigens to be considered in cancer vaccine design.

The prognostic value of immune checkpoints in oral squamous cell carcinoma

BACKGROUND

Despite the importance of immune checkpoints in immunotherapy, the prognostic value of these molecules remains controversial in oral squamous cell carcinoma (OSCC). We performed a systematic review to investigate the prognostic significance of the immune checkpoints in OSCC.

MATERIALS

A systematic search was conducted in Ovid Medline, Scopus and Cochrane libraries, and all studies that evaluated the prognostic significance of immune checkpoints in OSCC were systematically retrieved.

RESULTS

Twelve immune checkpoints/modulators were studied for their prognostic values in OSCC patients between 1985 and 2017. Seven immune checkpoints (FKBP51, B7-H4, B7-H6, ALHD1, PD-L1, B7-H3 and IDO1) were reported to be associated with poor patients' survival in at least one study, and five (CTLA-4, TLT-2, VISTA, PD-L2 and PD-1) did not have a significant prognostic value. PD-L1 results were controversial as it was reported to be associated with both better and worse patients' survival.

CONCLUSIONS

Even though immune checkpoint markers had high expectation for OSCC prognostication, our systematic review revealed that the majority of them had been studied only once. The other molecules, which had been studied more than once, had controversial findings, except B7-H3.

Mitigating SOX2-potentiated Immune Escape of Head and Neck Squamous Cell Carcinoma with a STING-inducing Nanosatellite Vaccine

Purpose: The response rates of Head and Neck Squamous Cell Carcinoma (HNSCC) to checkpoint blockade are below 20%. We aim to develop a mechanism-based vaccine to prevent HNSCC immune escape.Experimental Design: We performed RNA-Seq of sensitive and resistant HNSCC cells to discover central pathways promoting resistance to immune killing. Using biochemistry, animal models, HNSCC microarray, and immune cell deconvolution, we assessed the role of SOX2 in inhibiting STING-type I interferon (IFN-I) signaling-mediated antitumor immunity. To bypass SOX2-potentiated STING suppression, we engineered a novel tumor antigen-targeted nanosatellite vehicle to enhance the efficacy of STING agonist and sensitize SOX2-expressing HNSCC to checkpoint blockade.Results: The DNA-sensing defense response is the most suppressed pathway in immune-resistant HNSCC cells. We identified SOX2 as a novel inhibitor of STING. SOX2 facilitates autophagy-dependent degradation of STING and inhibits IFN-I signaling. SOX2 potentiates an immunosuppressive microenvironment and promotes HNSCC growth in vivo in an IFN-I-dependent fashion. Our unique nanosatellite vehicle significantly enhances the efficacy of STING agonist. We show that the E6/E7-targeted nanosatellite vaccine expands the tumor-specific CD8⁺ T cells by over 12-fold in the tumor microenvironment and reduces tumor burden. A combination of nanosatellite vaccine with anti-PD-L1 significantly expands tumor-specific CTLs and limits the populations expressing markers for exhaustion, resulting in more effective tumor control and improved survival.Conclusions: SOX2 dampens the immunogenicity of HNSCC by targeting the STING pathway for degradation. The nanosatellite vaccine offers a novel and effective approach to enhance the adjuvant potential of STING agonist and break cancer tolerance to immunotherapy. Clin Cancer Res; 24(17); 4242-55. ©2018 AACR.