Inhibitors of the PD-1/PD-L1 axis for the treatment of head and neck cancer: current status and future perspectives

PER2 interaction with HSP70 promotes cuproptosis in oral squamous carcinoma cells by decreasing AKT stability

Oral squamous cell carcinoma (OSCC) has a poor prognosis, with unclear mechanisms posing a challenge for the development of effective treatment strategies. Cuproptosis is a novel cell death mode that disrupts mitochondrial metabolism. Clarifying the mechanisms that regulate cuproptosis may provide important new insights to guide OSCC treatment. Here, we found that the biological clock gene Period2 (PER2) was under-expressed in OSCC, with consequent inhibition of cellular cuproptosis, whereas it was overexpression of PER2 in vitro and in vivo and promoted OSCC cellular cuproptosis. Mechanistically, PER2 bound to heat shock protein 70 (HSP70) through its C-terminal domain, subsequently reducing the interaction between HSP70 and AKT and leading to enhanced degradation of AKT ubiquitination, and promoting cuproptosis in OSCC cells by inhibiting the AKT pathway and upregulating DLAT, PDHB, and SLC31A1 expression. Activating transcription factor 3 (ATF3) is an upstream regulator of PER2, that binds to the -807 to -796 bp site of the PER2 promoter. Overexpression of ATF3 in vitro and in vivo is dependent on transcriptional activation of PER2 and promotes cuproptosis in OSCC cells. The anti-tumor effect of ATF3 inducer 1-targeted upregulation of PER2 combined with copper ionophore elesclomol (ES) was found to be significantly enhanced compared with that of monotherapy in an OSCC xenograft model. These findings reveal a critical role of ATF3-dependent regulation of cuproptosis by PER2 in OSCC development, suggesting targeted upregulation of PER2 or ATF3 in combination to induce cuproptosis as a novel strategy to potentially improve the prognosis of OSCC patients.

Axl Regulation of NK Cell Activity Creates an Immunosuppressive Tumor Immune Microenvironment in Head and Neck Cancer

Background: Head and neck cancer (HNC) evades immune responses by manipulating the tumor immune microenvironment (TIME). Tumor-bound Axl has been implicated in promoting an immunosuppressive TIME in HNC, though its precise role remains unclear. Understanding Axl's contribution to immune evasion in HNC could lead to the identification of new therapeutic targets; therapies directed at these targets could be combined with and thereby enhance immunotherapies. Results: Using Axl knockout (Axl KO) cell lines derived from the immunologically "cold" MOC2 mouse model, we found that Axl loss delayed tumor growth in immunocompetent mice. This was accompanied by reduced immunosuppressive cells, including MDSCs, Tregs, B cells, and neutrophils, and increased infiltration of cytotoxic CD8 T cells and NK cells. To identify the immune population(s) responsible for these changes, Axl KO tumors were implanted in immune-deficient mice. Axl KO tumor growth in athymic nude mice (which lack T cells) was unchanged, whereas tumor growth in NCG mice (which lack NK cells) was rescued, suggesting that NK cells mediate the Axl KO tumor growth delay. Further, Axl loss enhanced NK cell cytotoxicity in vitro and in vivo, and NK cell depletion reversed delayed Axl KO tumor growth. Mechanistically, Axl KO tumors showed decreased expression of CD73 and CCL2, which inhibit NK cells, and increased expression of CCL5 and CXCL10, which promote NK cell recruitment and activation. Conclusions: These novel findings suggest that tumor-bound Axl fosters an immunosuppressive TIME by inhibiting NK cell recruitment and function, thereby promoting tumor growth. Targeting Axl may enhance NK cell-mediated tumor killing and improve immunotherapy efficacy in HNC.

Enhancing CD4+/CD8+ T cell ratio and accelerating recovery in HNSCC patients through immunonutrition intervention

OBJECTIVE

Malnutrition is a common issue in patients with head and neck squamous cell carcinoma (HNSCC), leading to compromised immune function and diminished treatment efficacy. This is particularly concerning for therapies targeting the PD-1 pathway, which are pivotal in cancer treatment. The aim of this retrospective study was to explore the potential benefits of immunonutrition in improving immune responses and clinical outcomes for these patients.

METHODS

In the study, 49 individuals diagnosed with HNSCC were enrolled and divided into two groups: one group received specialized immunonutrition support designed to enhance immune function, while the other group received standard nutritional care. The researchers assessed immune function by evaluating CD4+ and CD8+ T cell counts, which are critical indicators of immune health. Additionally, clinical outcomes were monitored, focusing on infection rates and the duration of hospital stays.

RESULTS

Patients who received immunonutrition showed a significant improvement in immune function, as indicated by higher levels of CD4+ and CD8+ T cells. Furthermore, these patients experienced shorter recovery times and lower infection rates compared to those receiving standard nutrition.

CONCLUSION

These findings suggest that immunonutrition may play a vital role in enhancing the effectiveness of cancer therapies, including PD-1 inhibitors. By supporting immune health, immunonutrition could potentially improve patient outcomes and quality of life during and after treatment. This study underscores the importance of integrating nutritional support into cancer care, particularly for patients with HNSCC. As the field of oncology continues to evolve, incorporating strategies that address nutritional deficiencies could be key to optimizing treatment efficacy and improving overall survival rates.

The membrane-associated ubiquitin ligase MARCHF8 promotes cancer immune evasion by degrading MHC class I proteins

The loss of major histocompatibility complex class I (MHC-I) molecules has been proposed as a mechanism by which cancer cells evade tumor-specific T cells in immune checkpoint inhibitor (ICI)-refractory patients. Nevertheless, the mechanism by which cancer cells downregulate MHC-I is poorly understood. We report here that membrane-associated RING-CH-type finger 8 (MARCHF8), upregulated by human papillomavirus (HPV), ubiquitinates and degrades MHC-I proteins in HPV-positive head and neck cancer (HPV+ HNC). MARCHF8 knockdown restores MHC-I levels on HPV+ HNC cells. We further reveal that Marchf8 knockout significantly suppresses tumor growth and increases the infiltration of natural killer (NK) and T cells in the tumor microenvironment (TME). Furthermore, Marchf8 knockout markedly increases crosstalk between the cytotoxic NK cells and CD8 + T cells with macrophages and enhances the tumor cell-killing activity of CD8 + T cells. CD8 + T cell depletion in mice abrogates Marchf8 knockout-driven tumor suppression and T cell infiltration. Interestingly, Marchf8 knockout, in combination with anti-PD-1 treatment, synergistically suppresses tumor growth in mice bearing ICI-refractory tumors. Taken together, our finding suggests that MARCHF8 could be a promising target for novel immunotherapy for HPV+ HNC patients.

One Sentence Summary

Targeting MARCHF8 restores MHC-I proteins, induces antitumor CD8 + T cell activity, and suppresses the growth of ICI-refractory tumors.

Soluble forms of PD-1 and sPD-L1/2 in serum and urine of patients with head and neck cancer and their clinical significance

    This study explored the soluble forms of PD-1 and sPD-L1/2 in serum and urine of patients with head and neck cancer (HNCs) and associated the data with clinical state and 5-year survival. The sPD-1 and sPD-L1/2 levels were evaluated by ELISA in sufferers (N=110) and normal controls (N=82). Patients in the case group were more likely to be male smokers or former smokers. Compared with the normal control group, the serum levels of sPD-1, sPD-L1 and sPD-L2 and the urine level of sPD-L1 in patients with HNCs were increased. Furthermore, sPD-1 and sPD-L1 serum levels existed a positive connection, and sPD-1 and sPD-L2 serum levels positively correlated in HNCs sufferers. The urine sPD-1 and sPD-L1 had a positive relationship. sPD-1 serum levels had a positive connection with urine sPD-1, sPD-L1 urine levels had a positive relationship with sPD-L1, and sPD-L2 serum levels positively connected to urine sPD-L2. Lower serum sPD-1 and sPD-L1/L2 were associated with disease progression and survival at the examination time. sPD-1 and sPD-L1/L2 serum levels above median were markedly related to a decreased probability of 5-years OS in patients with HNCs. The sPD-1 and sPD-L1/2 were complementary markers representing clinical condition and illness outcomes for HNCs patients. The sPD-L1 might accelerate the characterization of high-risk patients with disapproving illness outcomes. sPD-1 and sPD-L1/2 could be easily accessed through liquid biopsy. The incorporation of them as indicators for risk evaluation throughout treatment scheduling and follow-up seems to be an appreciated method.

Immune Escape Strategies in Head and Neck Cancer: Evade, Resist, Inhibit, Recruit

Head and neck cancers (HNCs) arise from the mucosal lining of the aerodigestive tract and are often associated with alcohol use, tobacco use, and/or human papillomavirus (HPV) infection. Over 600,000 new cases of HNC are diagnosed each year, making it the sixth most common cancer worldwide. Historically, treatments have included surgery, radiation, and chemotherapy, and while these treatments are still the backbone of current therapy, several immunotherapies have recently been approved by the Food and Drug Administration (FDA) for use in HNC. The role of the immune system in tumorigenesis and cancer progression has been explored since the early 20th century, eventually coalescing into the current three-phase model of cancer immunoediting. During each of the three phases-elimination, equilibrium, and escape-cancer cells develop and utilize multiple strategies to either reach or remain in the final phase, escape, at which point the tumor is able to grow and metastasize with little to no detrimental interference from the immune system. In this review, we summarize the many strategies used by HNC to escape the immune system, which include ways to evade immune detection, resist immune cell attacks, inhibit immune cell functions, and recruit pro-tumor immune cells.

PER2 binding to HSP90 enhances immune response against oral squamous cell carcinoma by inhibiting IKK/NF-κB pathway and PD-L1 expression

BACKGROUND

Programmed death-ligand 1 (PD-L1) contributes to the immune escape of tumor cells and is a critical target for antitumor immunotherapy. However, the molecular mechanisms regulating PD-L1 expression remain unclear, hindering the development of effective therapies. Here we investigate the role and molecular mechanism of the core clock gene Period2 (PER2) in regulating PD-L1 expression and its role in the combination therapy of oral squamous cell carcinoma (OSCC).

METHODS

Quantitative real-time PCR, western blotting or immunohistochemistry to detect expression of PER2 and PD-L1 in OSCC tissues and cells. Overexpression and knockdown of PER2 detects the function of PER2. Bioinformatics, immunoprecipitation, GST pull-down, CHX chase assay and western blot and strip to detect the mechanism of PER2 regulation for PD-L1. A humanized immune reconstitution subcutaneous xenograft mouse model was established to investigate the combination therapy efficacy.

RESULTS

In OSCC tissues and cells, PER2 expression was reduced and PD-L1 expression was increased, the expression of PER2 was significantly negatively correlated with PD-L1. In vitro and in vivo experiments demonstrated that PER2 inhibited PD-L1 expression and enhanced T-cell-mediated OSCC cell killing by suppressing the IKK/NF-κB pathway. Mechanistically, PER2 binds to heat shock protein 90 (HSP90) through the PAS1 domain and reduces the interaction of HSP90 with inhibitors of kappa B kinase (IKKs), promoting the ubiquitination of IKKα/β and p65 nuclear translocation to inhibit IKK/NF-κB pathway, thereby suppressing PD-L1 expression. In humanized immune reconstitution subcutaneous xenograft mouse model, it was demonstrated that PER2 targeting combined with anti-PD-L1 treatment improved the inhibition of OSCC growth by promoting CD8+ T-cell infiltration into the tumor.

CONCLUSIONS

Our findings reveal the role and mechanism of PD-L1 regulation by PER2 and support the potential clinical application of PER2 targeting in combination with anti-PD-L1 in OSCC immunotherapy.

New immunotherapeutic approaches for cancer treatment

Neoplasms are a worldwide recognized non-contagious disease which has the most mortality rate after cardiovascular diseases. For decades, there has been a vast amount of study on treatment methods of cancer which has led to conventional therapies such as chemotherapy, radiation therapy, surgery and so on. Clinicians and researchers believed that there is an urgent need, considering the high rate of incidence and prevalence, for an alternative treatment option which is more efficacious and has less adverse effects than the above-mentioned treatments. Immunotherapy has emerged as a potential treatment alternative in a few years and became one of the fastest developing therapeutic approaches. Different kinds of immunotherapies are FDA approved and available for treatment of various cancer types. In this review, we have summarized the major immunotherapy methods including checkpoint inhibitors, CAR T cell therapies and cancer vaccines. Furthermore, application of combination therapy, precision medicine, biomarker discovery, overcoming resistance and reduction of adverse effects are discussed in this study.

Dual Axl/MerTK inhibitor INCB081776 creates a proinflammatory tumor immune microenvironment and enhances anti-PDL1 efficacy in head and neck cancer

BACKGROUND

The tyrosine kinase receptors Axl and MerTK are highly overexpressed in head and neck cancer (HNC) cells, where they are critical drivers of survival, proliferation, metastasis, and therapeutic resistance.

METHODS

We investigated the role of Axl and MerTK in creating an immunologically "cold" tumor immune microenvironment (TIME) by targeting both receptors simultaneously with a small molecule inhibitor of Axl and MerTK (INCB081776). Effects of INCB081776 and/or anti-PDL1 on mouse oral cancer (MOC) cell growth and on the TIME were evaluated.

RESULTS

Targeting Axl and MerTK can reduce M2 and induce M1 macrophage polarization. In vivo, INCB081776 treatment alone or with anti-PDL1 appears to slow MOC tumor growth, increase proinflammatory immune infiltration, and decrease anti-inflammatory immune infiltration.

CONCLUSIONS

This data indicates that simultaneous targeting of Axl and MerTK with INCB081776, either alone or in combination with anti-PDL1, slows tumor growth and creates a proinflammatory TIME in mouse models of HNC.

Divergent outcomes of anti-PD-L1 treatment coupled with host-intrinsic differences in TCR repertoire and distinct T cell activation states in responding versus non-responding tumors

Differential responses to immune checkpoint inhibitors (ICI) may be attributed to tumor-intrinsic factors or environmental cues; however, these mechanisms cannot fully explain the variable ICI responses in different individuals. Here, we investigate the potential contribution of immunological heterogeneity with a focus on differences in T-cell receptor (TCR) repertoire to ICI responses, which has not been defined previously. To reveal additional factors underlying heterogeneous responses to ICI, we employed a squamous cell carcinoma (SCC) mouse model in which tumor-bearing recipients unambiguously diverged into responders (R) or non-responders (NR) upon anti-PD-L1 treatment. Treatment efficacy absolutely required CD8 T-cells and correlated positively with effector functions of CD8 tumor-infiltrating lymphocytes (TILs). We showed that TCR repertoires exhibited a similar magnitude of clonal expansion in R vs. NR CD8 TILs. However, the top expanded TCR clonotypes appeared to be mutually exclusive between R and NR CD8 TILs, which also occurred in a recipient-specific manner, demonstrating preferential expansion of distinct TCR clonotypes against the same SCC tumor. Unexpectedly, R vs. NR CD8 TILs reached all activation clusters and did not exhibit substantial global differences in transcriptomes. By linking single-cell transcriptomic data with unique TCR clonotypes, CD8 TILs harboring top TCR clonotypes were found to occupy distinct activation clusters and upregulate genes favoring anti-tumor immunity to different extents in R vs. NR. We conclude that stochastic differences in CD8 TIL TCR repertoire and distinct activation states of top TCR clonotypes may contribute to differential anti-PD-L1 responses. Our study suggests that host-intrinsic immunological heterogeneity may offer a new explanation for differential ICI responses in different individuals, which could impact on strategies for personalized cancer immunotherapy.

Thyroid Hormone Induces Oral Cancer Growth via the PD-L1-Dependent Signaling Pathway

Oral cancer is a fatal disease, and its incidence in Taiwan is increasing. Thyroid hormone as L-thyroxine (T₄) stimulates cancer cell proliferation via a receptor on integrin αvβ3 of plasma membranes. It also induces the expression of programmed death-ligand 1 (PD-L1) and cell proliferation in cancer cells. Thyroid hormone also activates β-catenin-dependent cell proliferation in cancer cells. However, the relationship between PD-L1 and cancer proliferation is not fully understood. In the current study, we investigated the role of inducible thyroid hormone-induced PD-L1-regulated gene expression and proliferation in oral cancer cells. Thyroxine bound to integrin αvβ3 to induce PD-L1 expressions via activation of ERK1/2 and signal transducer and activator of transcription 3 (STAT3). Inactivated STAT3 inhibited PD-L1 expression and nuclear PD-L1 accumulation. Inhibition of PD-L1 expression reduced β-catenin accumulation. Furthermore, nuclear PD-L1 formed a complex with nuclear proteins such as p300. Suppression PD-L1 expression by shRNA blocked not only expression of PD-L1 and β-catenin but also signal transduction, proliferative gene expressions, and cancer cell growth. In summary, thyroxine via integrin αvβ3 activated ERK1/2 and STAT3 to stimulate the PD-L1-dependent and β-catenin-related growth in oral cancer cells.

During early stages of cancer, neutrophils initiate anti-tumor immune responses in tumor-draining lymph nodes

Tumor-draining lymph nodes (LNs) play a crucial role during cancer spread and in initiation of anti-cancer adaptive immunity. Neutrophils form a substantial population of cells in LNs with poorly understood functions. Here, we demonstrate that, during head and neck cancer (HNC) progression, tumor-associated neutrophils transmigrate to LNs and shape anti-tumor responses in a stage-dependent manner. In metastasis-free stages (N0), neutrophils develop an antigen-presenting phenotype (HLA-DR⁺CD80⁺CD86⁺ICAM1⁺PD-L1^-) and stimulate T cells (CD27⁺Ki67^highPD-1^-). LN metastases release GM-CSF and via STAT3 trigger development of PD-L1⁺ immunosuppressive neutrophils, which repress T cell responses. The accumulation of neutrophils in T cell-rich zones of LNs in N0 constitutes a positive predictor for 5-year survival, while increased numbers of neutrophils in LNs of N1-3 stages predict poor prognosis in HNC. These results suggest a dual role of neutrophils as essential regulators of anti-cancer immunity in LNs and argue for approaches fostering immunostimulatory activity of these cells during cancer therapy.

Immune Checkpoint Inhibitors in Cancer Therapy

The discovery of immune checkpoint proteins such as PD-1/PDL-1 and CTLA-4 represents a significant breakthrough in the field of cancer immunotherapy. Therefore, humanized monoclonal antibodies, targeting these immune checkpoint proteins have been utilized successfully in patients with metastatic melanoma, renal cell carcinoma, head and neck cancers and non-small lung cancer. The US FDA has successfully approved three different categories of immune checkpoint inhibitors (ICIs) such as PD-1 inhibitors (Nivolumab, Pembrolizumab, and Cemiplimab), PDL-1 inhibitors (Atezolimumab, Durvalumab and Avelumab), and CTLA-4 inhibitor (Ipilimumab). Unfortunately, not all patients respond favourably to these drugs, highlighting the role of biomarkers such as Tumour mutation burden (TMB), PDL-1 expression, microbiome, hypoxia, interferon-γ, and ECM in predicting responses to ICIs-based immunotherapy. The current study aims to review the literature and updates on ICIs in cancer therapy.

Differential responses to immune checkpoint inhibitor dictated by pre-existing differential immune profiles in squamous cell carcinomas caused by same initial oncogenic drivers

BACKGROUND

While immune checkpoint inhibitors (ICI) were approved for head and neck squamous cell carcinomas (HNSCCs), the response rate remains relatively low. Mechanisms underlying ICI unresponsiveness versus sensitivity are not fully understood.

METHOD

To better delineate differential responses to ICI treatment, we employed mouse SCC models, termed KPPA tumors that were caused by deleting p53 and hyperactivating PIK3CA, two most frequently mutated genes in human HNSCCs. We transplanted two KPPA tumor lines (TAb2 versus TCh3) into C57BL/6 recipients and examined the immune tumor microenvironment using flow cytometry. Furthermore, we employed single-cell RNA sequencing to identify the difference in tumor infiltrating lymphocytes (TILs).

RESULTS

We found that different KPPA tumors exhibited heterogeneous immune profiles pre-existing treatment that dictated their sensitivity or unresponsiveness to anti-PD-L1. Unresponsive TAb2 tumors were highly enriched with functional tumor-associated macrophages (TAMs), especially M2-TAMs. In contrast, sensitive TCh3 tumors contained more CD8 TILs with better effector functions. TAb2 tumor cells drastically expanded F4/80+ TAMs from bone marrow precursors, requiring CSF1 and VEGF. Consistently, a higher combined expression of VEGF-C and CSF1 predicts worse survival in PIK3CAAmp/TP53Mutated HNSCC patients. Unresponsive TAb2 tumors upregulated distinct signaling pathways that correlate with aggressive tumor phenotypes. While anti-PD-L1 did not affect the TME of TAb2 tumors, it significantly increased the number of CD8 TILs in TCh3 tumors.

CONCLUSIONS

We uncovered tumor-intrinsic differences that may underlie the differential responses to ICI by establishing and employing two SCC tumor lines, TAb2 vs. TCh3, both of which harbor TP53 deletion and PIK3CA hyperactivation. Our study indicates the limitation of stratifying cancers according to their genetic alterations and suggests that evaluating HNSCC tumor-intrinsic cues along with immune profiles in the TME may help better predict ICI responses. Our experimental models may provide a platform for pinpointing tumor-intrinsic differences underlying an immunosuppressive TME in HNSCCs and for testing combined immunotherapies targeting either tumor-specific or TAM-specific players to improve ICI efficacy.

Combination of Radiosensitivity Gene Signature and PD-L1 Status Predicts Clinical Outcome of Patients With Locally Advanced Head and Neck Squamous Cell Carcinoma: A Study Based on The Cancer Genome Atlas Dataset

Aim: The aim of our study was to investigate the potential predictive value of the combination of radiosensitivity gene signature and PD-L1 expression for the prognosis of locally advanced head and neck squamous cell carcinoma (HNSCC).

Methods: The cohort was selected from The Cancer Genome Atlas (TCGA) and classified into the radiosensitive (RS) group and radioresistant (RR) group by a radiosensitivity-related gene signature. The cohort was also grouped as PD-L1-high or PD-L1-low based on PD-L1 mRNA expression. The least absolute shrinkage and selection operator (lasso)-based Cox model was used to select hub survival genes. An independent validation cohort was obtained from the Gene Expression Omnibus (GEO) database.

Results: We selected 288 locally advanced HNSCC patients from TCGA. The Kaplan–Meier method found that the RR and PD-L1-high group had a worse survival than others (p = 0.033). The differentially expressed gene (DEG) analysis identified 553 upregulated genes and 486 downregulated genes (p < 0.05, fold change >2) between the RR and PD-L1-high group and others. The univariate Cox analysis of each DEG and subsequent lasso-based Cox model revealed five hub survival genes (POU4F1, IL34, HLF, CBS, and RNF165). A further hub survival gene-based risk score model was constructed, which was validated by an external cohort. We observed that a higher risk score predicted a worse prognosis (p = 0.0013). The area under the receiver operating characteristic curve (AUC) plots showed that this risk score model had good prediction value (1-year AUC = 0.684, 2-year AUC = 0.702, and 3-year AUC = 0.688). Five different deconvolution methods all showed that the B cells were lower in the RR and PD-L1-high group (p < 0.05). Finally, connectivity mapping analysis showed that the histone deacetylase (HDAC) inhibitor trichostatin A might have the potential to reverse the phenotype of RR and PD-L1-high in locally advanced HNSCC (p < 0.05, false discovery rate <0.1).

Conclusion: The combination of 31-gene signature and the PD-L1 mRNA expression had a potential predictive value for the prognosis of locally advanced HNSCC who had RT. The B cells were lower in the RR and PD-L1-high group. The identified risk gene signature of locally advanced HNSCC and the potential therapeutic drug trichostatin A for the RR and PD-L1-high group are worth being further studied in a prospective homogenous cohort.

Wnt Inhibition Sensitizes PD-L1 Blockade Therapy by Overcoming Bone Marrow-Derived Myofibroblasts-Mediated Immune Resistance in Tumors

Cancer-associated fibroblasts (CAFs) has been recognized as one cause of tumor resistance to immune checkpoint blockade therapy, but the underlying mechanisms still remain elusive. In the present study, a bone marrow-derived CAF (BMF) -rich tumor model is successfully established by subcutaneously mixed inoculation of BMFs and tumor cells into mice and the BMF-mixed tumor xenografts are demonstrated to be resistant to anti-PD-L1 antibody immunotherapy compared to the mere tumor xenografts. In vitro assays via the co-culture system of BMFs and tumor cells indicate that the co-cultured BMFs are induced to overexpress PD-L1, while there is no such a phenomenon in the co-cultured cancer cells. The further knock-out of PD-L1 in BMFs rescues the sensitivity of BMF-mixed tumor xenografts to PD-L1 blockade therapy. Mechanistically, via the microarray assay, we identify that the upregulation of PD-L1 in BMFs stimulated by cancer cells is medicated by the activation of the Wnt/β-catenin signaling pathway in BMFs. Moreover, the administration of Wnt/β-catenin signaling inhibitors, including XAV-939 and Wnt-C59, distinctly inhibits the upregulation of PD-L1 expression in the co-cultured BMFs. The further combination administration of XAV-939 significantly potentiates the therapeutic outcome of PD-L1 blockade therapy in BMF-mixed tumors. In summary, our study demonstrates that Wnt inhibition augments PD-L1 blockade efficacy by overcoming BMF-mediated immunotherapy resistance.

Differences in TCR repertoire and T cell activation underlie the divergent outcomes of antitumor immune responses in tumor-eradicating versus tumor-progressing hosts

Background

Antitumor immunity is highly heterogeneous between individuals; however, underlying mechanisms remain elusive, despite their potential to improve personalized cancer immunotherapy. Head and neck squamous cell carcinomas (HNSCCs) vary significantly in immune infiltration and therapeutic responses between patients, demanding a mouse model with appropriate heterogeneity to investigate mechanistic differences.

Methods

We developed a unique HNSCC mouse model to investigate underlying mechanisms of heterogeneous antitumor immunity. This model system may provide a better control for tumor-intrinsic and host-genetic variables, thereby uncovering the contribution of the adaptive immunity to tumor eradication. We employed single-cell T-cell receptor (TCR) sequencing coupled with single-cell RNA sequencing to identify the difference in TCR repertoire of CD8 tumor-infiltrating lymphocytes (TILs) and the unique activation states linked with different TCR clonotypes.

Results

We discovered that genetically identical wild-type recipient mice responded heterogeneously to the same squamous cell carcinoma tumors orthotopically transplanted into the buccal mucosa. While tumors initially grew in 100% of recipients and most developed aggressive tumors, ~25% of recipients reproducibly eradicated tumors without intervention. Heterogeneous antitumor responses were dependent on CD8 T cells. Consistently, CD8 TILs in regressing tumors were significantly increased and more activated. Single-cell TCR-sequencing revealed that CD8 TILs from both growing and regressing tumors displayed evidence of clonal expansion compared with splenic controls. However, top TCR clonotypes and TCR specificity groups appear to be mutually exclusive between regressing and growing TILs. Furthermore, many TCRα/TCRβ sequences only occur in one recipient. By coupling single-cell transcriptomic analysis with unique TCR clonotypes, we found that top TCR clonotypes clustered in distinct activation states in regressing versus growing TILs. Intriguingly, the few TCR clonotypes shared between regressors and progressors differed greatly in their activation states, suggesting a more dominant influence from tumor microenvironment than TCR itself on T cell activation status.

Conclusions

We reveal that intrinsic differences in the TCR repertoire of TILs and their different transcriptional trajectories may underlie the heterogeneous antitumor immune responses in different hosts. We suggest that antitumor immune responses are highly individualized and different hosts employ different TCR specificities against the same tumors, which may have important implications for developing personalized cancer immunotherapy.

Development of an Immunogenomic Landscape-Based Prognostic Index of Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the eighth leading cancer by incidence worldwide, with approximately 700,000 new cases in 2018 (accounting for 11% of all cancers). The occurrence and development of tumors are closely related to the immunological function of the body and sensitivity to treatment schemes as well as prognosis. It is urgent for clinicians to systematically study patients’ immune gene maps to help select a treatment plan and analyze the potential to cure HNSCC. Here, the transcriptomic data of HNSCC samples were downloaded from The Cancer Genome Atlas (TCGA), and 4,793 genes differentially expressed in normal and cancer tissues of HNSCC were identified, including 1,182 downregulated and 3,611 upregulated genes. From these genes, 400 differentially expressed immune-related genes (IRGs) were extracted, including 95 downregulated genes and 305 upregulated genes. The prognostic values of IRGs were evaluated by univariate Cox analysis, and 236 genes that were significantly related to the overall survival (OS) of patients were identified. The signaling pathways that play roles in the prognosis of IRGs were investigated by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, and the expression profiles of IRGs and OS in 499 HNSCC patients based on TCGA dataset were integrated. Potential molecular mechanisms and characteristics of these HNSCC-specific IRGs were further explored with the help of a new prognostic index based on IRGs developed by least absolute shrinkage and selection operator (LASSO) Cox analysis. A total of 64 hub genes (IRGs associated with prognosis) were markedly associated with the clinical outcome of HNSCC patients. KEGG functional enrichment analysis revealed that these genes were actively involved in several pathways, e.g., cytokine–cytokine receptor interaction, T-cell receptor signaling, and natural killer cell-mediated cytotoxicity. IRG-based prognostic signatures performed moderately in prognostic predictions. Interestingly, the prognostic index based on IRGs reflected infiltration by several types of immune cells. These data screened several IRGs of clinical significance and revealed drivers of the immune repertoire, demonstrating the importance of a personalized IRG-based immune signature in the recognition, surveillance, and prognosis of HNSCC.

NDAT Targets PI3K-Mediated PD-L1 Upregulation to Reduce Proliferation in Gefitinib-Resistant Colorectal Cancer

The property of drug-resistance may attenuate clinical therapy in cancer cells, such as chemoresistance to gefitinib in colon cancer cells. In previous studies, overexpression of PD-L1 causes proliferation and metastasis in cancer cells; therefore, the PD-L1 pathway allows tumor cells to exert an adaptive resistance mechanism in vivo. Nano-diamino-tetrac (NDAT) has been shown to enhance the anti-proliferative effect induced by first-line chemotherapy in various types of cancer, including colorectal cancer (CRC). In this work, we attempted to explore whether NDAT could enhance the anti-proliferative effect of gefitinib in CRC and clarified the mechanism of their interaction. The MTT assay was utilized to detect a reduction in cell proliferation in four primary culture tumor cells treated with gefitinib or NDAT. The gene expression of PD-L1 and other tumor growth-related molecules were quantified by quantitative polymerase chain reaction (qPCR). Furthermore, the identification of PI3K and PD-L1 in treated CRC cells were detected by western blotting analysis. PD-L1 presentation in HCT116 xenograft tumors was characterized by specialized immunohistochemistry (IHC) and the hematoxylin and eosin stain (H&E stain). The correlations between the change in PD-L1 expression and tumorigenic characteristics were also analyzed. (3) The PD-L1 was highly expressed in Colo_160224 rather than in the other three primary CRC cells and HCT-116 cells. Moreover, the PD-L1 expression was decreased by gefitinib (1 µM and 10 µM) in two cells (Colo_150624 and 160426), but 10 µM gefitinib stimulated PD-L1 expression in gefitinib-resistant primary CRC Colo_160224 cells. Inactivated PI3K reduced PD-L1 expression and proliferation in CRC Colo_160224 cells. Gefitinib didn’t inhibit PD-L1 expression and PI3K activation in gefitinib-resistant Colo_160224 cells. However, NDAT inhibited PI3K activation as well as PD-L1 accumulation in gefitinib-resistant Colo_160224 cells. The combined treatment of NDAT and gefitinib inhibited pPI3K and PD-L1 expression and cell proliferation. Additionally, NDAT reduced PD-L1 accumulation and tumor growth in the HCT116 (K-RAS mutant) xenograft experiment. (4) Gefitinib might suppress PD-L1 expression but did not inhibit proliferation through PI3K in gefitinib-resistant primary CRC cells. However, NDAT not only down-regulated PD-L1 expression via blocking PI3K activation but also inhibited cell proliferation in gefitinib-resistant CRCs.

microRNAs in oral cancer: Moving from bench to bed as next generation medicine

Oral cancer is the thirteenth most common cancer in the world, with India contributing to 33% of the global burden. Lack of specific non-invasive markers, non-improvement in patient survival and tumor recurrence remain a major clinical challenge in oral cancer. Epigenetic regulation in the form of microRNAs (miRs) that act as tumor suppressor miRs or oncomiRs has gained significant momentum with the advancement in the field, suggesting the potential for clinical application of miRs in oral cancer. The current review of literature identified miR-21, miR-27a(-3p), miR-31, miR-93, miR-134, miR-146, miR-155, miR-196a, miR-196b, miR-211, miR-218, miR-222, miR-372 and miR-373 to be up-regulated and let-7a, let-7b, let-7c, let-7d, let-7e, let-7f, let-7g, let-7i, miR-26a, miR-99a-5p, miR-137, miR-139-5p, miR-143-3p, miR-184 and miR-375 to be down-regulated in oral cancer. Mechanistic studies have uncovered several miRs that are deregulated at varying levels and in different stages of oral cancer progression, thus providing clinical utility in better diagnosis as well as usefulness in prognosis by identifying patients with poor prognosis or stratifying patients based on responsiveness to chemo- and radio-therapy. Lastly, exogenous modulation of miR expression using miRNA-based drugs in combination with first-line agents may be adopted as a new therapeutic modality to treat oral cancer. Knowledge of miRs and their involvement in key molecular processes, clinical association, responsiveness to therapy and clinical advancement may highlight additional avenues in order to improve patient morbidity and mortality. Furthermore, combinatorial approaches with miR-therapy may be efficacious in oral cancer.

NOX4 Inhibition Potentiates Immunotherapy by Overcoming Cancer-Associated Fibroblast-Mediated CD8 T-cell Exclusion from Tumors

Determining mechanisms of resistance to αPD-1/PD-L1 immune-checkpoint immunotherapy is key to developing new treatment strategies. Cancer-associated fibroblasts (CAF) have many tumor-promoting functions and promote immune evasion through multiple mechanisms, but as yet, no CAF-specific inhibitors are clinically available. Here we generated CAF-rich murine tumor models (TC1, MC38, and 4T1) to investigate how CAFs influence the immune microenvironment and affect response to different immunotherapy modalities [anticancer vaccination, TC1 (HPV E7 DNA vaccine), αPD-1, and MC38] and found that CAFs broadly suppressed response by specifically excluding CD8+ T cells from tumors (not CD4+ T cells or macrophages); CD8+ T-cell exclusion was similarly present in CAF-rich human tumors. RNA sequencing of CD8+ T cells from CAF-rich murine tumors and immunochemistry analysis of human tumors identified significant upregulation of CTLA-4 in the absence of other exhaustion markers; inhibiting CTLA-4 with a nondepleting antibody overcame the CD8+ T-cell exclusion effect without affecting Tregs. We then examined the potential for CAF targeting, focusing on the ROS-producing enzyme NOX4, which is upregulated by CAF in many human cancers, and compared this with TGFβ1 inhibition, a key regulator of the CAF phenotype. siRNA knockdown or pharmacologic inhibition [GKT137831 (Setanaxib)] of NOX4 "normalized" CAF to a quiescent phenotype and promoted intratumoral CD8+ T-cell infiltration, overcoming the exclusion effect; TGFβ1 inhibition could prevent, but not reverse, CAF differentiation. Finally, NOX4 inhibition restored immunotherapy response in CAF-rich tumors. These findings demonstrate that CAF-mediated immunotherapy resistance can be effectively overcome through NOX4 inhibition and could improve outcome in a broad range of cancers. SIGNIFICANCE: NOX4 is critical for maintaining the immune-suppressive CAF phenotype in tumors. Pharmacologic inhibition of NOX4 potentiates immunotherapy by overcoming CAF-mediated CD8+ T-cell exclusion. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/9/1846/F1.large.jpg.See related commentary by Hayward, p. 1799.

Synergistic combinations of paclitaxel and withaferin A against human non-small cell lung cancer cells

Platinum-taxane combination chemotherapy still represents the standard of care for advanced non-small cell lung cancer (NSCLC) with no targetable driver mutations. However, the efficacy of these drugs has plateaued at 10–14 months primarily due to dose-limiting toxicity, chemoresistance, and metastasis. Here, we explored the effects of withaferin A (WFA) alone and in combination with paclitaxel (PAC) on the growth, proliferation, migration, and invasion of human NSCLC cells. We show that the sensitivity of H1299 and A549 cells to concomitant treatment with PAC and WFA was greater than that of either PAC or WFA alone. Using the combination index and dose-reduction index, we demonstrated that various combinations (1:40, 1:20, 1:10) of PAC to WFA, respectively, were highly synergistic. In addition, PAC+WFA co-treatment synergistically inhibited colony formation, migration, invasion and increased the induction of apoptosis in H1299 and A549 cells. Interestingly, the synergism of PAC and WFA was not schedule-dependent but was enhanced when cells were pretreated with WFA indicating a chemo-sensitizing effect. Importantly, WFA was active against both PAC-sensitive (TS-A549) and PAC-resistant (TR-A549) cells both in vitro and in vivo. Mechanistically, WFA inhibits the proliferation of NSCLC cells via thiol oxidation. The effects of WFA were inhibited in the presence of N-acetyl cysteine and other thiol donors. Taken together, our results demonstrate the efficacy of WFA alone or alongside PAC on NSCLC cells and provide a strong rationale for further detailed testing in clinically relevant models for the development of PAC+WFA combination as an alternative therapeutic strategy for advanced NSCLC.

Biological Determinants of Chemo-Radiotherapy Response in HPV-Negative Head and Neck Cancer: A Multicentric External Validation

Purpose: Tumor markers that are related to hypoxia, proliferation, DNA damage repair and stem cell-ness, have a prognostic value in advanced stage HNSCC patients when assessed individually. Here we aimed to evaluate and validate this in a multifactorial context and assess interrelation and the combined role of these biological factors in determining chemo-radiotherapy response in HPV-negative advanced HNSCC. Methods: RNA sequencing data of pre-treatment biopsy material from 197 HPV-negative advanced stage HNSCC patients treated with definitive chemoradiotherapy was analyzed. Biological parameter scores were assigned to patient samples using previously generated and described gene expression signatures. Locoregional control rates were used to assess the role of these biological parameters in radiation response and compared to distant metastasis data. Biological factors were ranked according to their clinical impact using bootstrapping methods and multivariate Cox regression analyses that included clinical variables. Multivariate Cox regression analyses comprising all biological variables were used to define their relative role among all factors when combined. Results: Only few biomarker scores correlate with each other, underscoring their independence. The different biological factors do not correlate or cluster, except for the two stem cell markers CD44 and SLC3A2 (r = 0.4, p < 0.001) and acute hypoxia prediction scores which correlated with T-cell infiltration score, CD8⁺ T cell abundance and proliferation scores (r = 0.52, 0.56, and 0.6, respectively with p < 0.001). Locoregional control association analyses revealed that chronic (Hazard Ratio (HR) = 3.9) and acute hypoxia (HR = 1.9), followed by stem cell-ness (CD44/SLC3A2; HR = 2.2/2.3), were the strongest and most robust determinants of radiation response. Furthermore, multivariable analysis, considering other biological and clinical factors, reveal a significant role for EGFR expression (HR = 2.9, p < 0.05) and T-cell infiltration (CD8⁺T-cells: HR = 2.2, p < 0.05; CD8⁺T-cells/Treg: HR = 2.6, p < 0.01) signatures in locoregional control of chemoradiotherapy-treated HNSCC. Conclusion: Tumor acute and chronic hypoxia, stem cell-ness, and CD8⁺ T-cell parameters are relevant and largely independent biological factors that together contribute to locoregional control. The combined analyses illustrate the additive value of multifactorial analyses and support a role for EGFR expression analysis and immune cell markers in addition to previously validated biomarkers. This external validation underscores the relevance of biological factors in determining chemoradiotherapy outcome in HNSCC.

Spatial proximity between T and PD-L1 expressing cells as a prognostic biomarker for oropharyngeal squamous cell carcinoma

Background

Fulfilling the promise of cancer immunotherapy requires novel predictive biomarkers to characterise the host immune microenvironment. Deciphering the complexity of immune cell interactions requires an automated multiplex approach to histological analysis of tumour sections. We tested a new automatic approach to select tissue and quantify the frequencies of cell-cell spatial interactions occurring in the PD1/PD-L1 pathway, hypothesised to reflect immune escape in oropharyngeal squamous cell carcinoma (OPSCC).

Methods

Single sections of diagnostic biopsies from 72 OPSCC patients were stained using multiplex immunofluorescence (CD8, PD1, PD-L1, CD68). Following multispectral scanning and automated regions-of-interest selection, the Hypothesised Interaction Distribution (HID) method quantified spatial proximity between cells. Method applicability was tested by investigating the prognostic significance of co-localised cells (within 30 μm) in patients stratified by HPV status.

Results

High frequencies of proximal CD8⁺ and PD-L1⁺ (HR 2.95, p = 0.025) and PD1⁺ and PD-L1⁺ (HR 2.64, p = 0.042) cells were prognostic for poor overall survival in patients with HPV negative OPSCC (n = 31).

Conclusion

The HID method can quantify spatial interactions considered to reflect immune escape and generate prognostic information in OPSCC. The new automated approach is ready to test in additional cohorts and its applicability should be explored in research and clinical studies.

Inter- and intraobserver agreement of programmed death ligand 1 scoring in head and neck squamous cell carcinoma, urothelial carcinoma and breast carcinoma

AIMS

Programmed death-ligand 1 (PD-L1) expression by tumour cells (TC) is a mechanism for tumour immune escape through down-regulation of antitumour T cell responses and is a target for immunotherapy. PD-L1 status as a predictor of treatment response has led to the development of multiple biomarkers with different reference cut-offs. We assessed pathologist consistency in evaluating PD-L1 immunopositivity by examining the inter- and intraobserver agreement using various antibody clones and different cancer types.

METHODS AND RESULTS

PD-L1 expression in TC and immune cells (IC) was manually scored in 27 head and neck squamous cell carcinoma (HSCC), 30 urothelial carcinoma (UC) and breast carcinoma (BC) using three commercial clones (SP263, SP142, 22C3) and one platform-independent test (E1L3N). For interobserver agreement, PD-L1 status was evaluated blindly by three pathologists. For intraobserver agreement, PD-L1 expression was re-evaluated following a wash-out period. Intraclass correlation coefficient (ICC), overall percentage agreement (OPA) and κ-values were calculated. Using clinical algorithms, the percentage of PD-L1-positive cases in HSCC, BC and UC were 15-81%, 47-67% and 7-43%, respectively. The percentage of PD-L1 positive cases relied heavily on the algorithm/cut-off values used. Almost perfect interobserver agreement was achieved using SP263 and E1L3N in HSCC, 22C3, SP142 and E1L3N in BC and 22C3 in UC. The SP142 clone in UC and HSCC showed moderate agreement and was associated with lower ICC and decreased intraobserver concordance.

CONCLUSIONS

Excellent inter- and intraobserver agreement can be achieved using SP263, 22C3 and E1L3N, whereas PD-L1 scoring using SP142 clone is associated with a higher level of subjectivity.

CXCL14 suppresses human papillomavirus-associated head and neck cancer through antigen-specific CD8+ T-cell responses by upregulating MHC-I expression

Evasion of the host immune responses is critical for both persistent human papillomavirus (HPV) infection and associated cancer progression. We have previously shown that expression of the homeostatic chemokine CXCL14 is significantly downregulated by the HPV oncoprotein E7 during cancer progression. Restoration of CXCL14 expression in HPV-positive head and neck cancer (HNC) cells dramatically suppresses tumor growth and increases survival through an immune-dependent mechanism in mice. While CXCL14 recruits natural killer (NK) and T cells to the tumor microenvironment, the mechanism by which CXCL14 mediates tumor suppression through NK and/or T cells remained undefined. Here, we report that CD8⁺ T cells are required for CXCL14-mediated tumor suppression. Using a CD8⁺ T cell receptor transgenic model, we show that the CXCL14-mediated antitumor CD8⁺ T cell responses require antigen specificity. Interestingly, CXCL14 expression restores major histocompatibility complex class I (MHC-I) expression on HPV-positive HNC cells downregulated by HPV, and knockdown of MHC-I expression in HNC cells results in loss of tumor suppression even with CXCL14 expression. These results suggest that CXCL14 enacts antitumor immunity through restoration of MHC-I expression on tumor cells and promoting antigen-specific CD8⁺ T cell responses to suppress HPV-positive HNC.

An update of knowledge on PD-L1 in head and neck cancers: Physiologic, prognostic and therapeutic perspectives

Programmed cell death-ligand 1 (PD-L1) is a transmembrane protein that acts as a co-inhibitory factor in the immune response. Its receptor, programmed cell death protein 1 (PD-1), is found on immune cells, where binding to PD-L1 can reduce the proliferation of PD-1-positive cells, inhibit their cytokine secretion and induce apoptosis. PD-L1 in immune-privileged tissue plays a crucial role in peripheral tolerance. PD-L1 can be overexpressed in various malignancies, including oral squamous cell carcinoma, where it can attenuate the host immune response to tumour cells and has been associated with a worse prognosis. Monoclonal antibody therapies targeting the PD-1:PD-L1 axis have shown initial promise, but further research is needed to identify which patients will benefit. We provide an update of knowledge on PD-L1, including its structure, function and regulation. We also review studies on the overexpression of PD-L1 in cancer, specifically oral squamous cell carcinoma, and explore its potential value as a therapeutic target.

PD-1/PD-L1 Axis, Rather Than High-Mobility Group Alarmins or CD8+ Tumor-Infiltrating Lymphocytes, Is Associated With Survival in Head and Neck Squamous Cell Carcinoma Patients Who Received Surgical Resection

In current studies, the influence of tumor immune microenvironment on tumorigenesis and tumor progression has been widely explored. In the present study, we investigated the expression and significance of high mobility group box 1 (HMGB1), HMG nucleosome-binding protein 1 (HMGN1), the receptor programmed cell death 1 (PD-1) and its ligand programmed cell death ligand 1 (PD-L1) in head and neck squamous cell carcinoma (HNSCC). We explored whether HMGB1 and HMGN1 take part in recruiting T cells to HNSCC microenvironment. Furthermore, we assessed the prognostic value of HMG proteins, TILs, and PD-1/PD-L1 in postoperative patients. Tumor tissue sections were collected from 81 cases of patients with resectable HNSCC. All patients' information was integrated with clinical and pathological records, as well as follow-up data. We used immunohistochemistry to examine the subcellular localization and expression levels of HMGB1 and HMGN1, as well as tumor CD3+, CD8+, FOXP3+ lymphocyte infiltration, and the expression of immune inhibiting molecules PD-1/PD-L1. Results showed that there was no significant difference in the number of CD8+ and FOXP3+ T cells between the two groups with or without HMGB1 cytoplasmic expression in tumor tissues. The number of CD3+ T cells in HMGB1 cytoplasmic expression group (339.39 ± 230.76) was more than that in group without HMGB1 cytoplasmic expression (233.30 ± 230.91, P < 0.05). The number of CD3+, CD8+, and FOXP3+ T cells in HMGN1 cytoplasmic expression group [400.74 ± 224.04, 158.10 ± 112.10, 36.00(15.00, 69.00)] was more than that in group without HMGN1-cytoplasmic expression [222.84 ± 217.78, P < 0.01; 105.10 ± 108.25, P < 0.05; 13.00(6.75, 32.25), P < 0.01]. The positive rates of PD-1 and PD-L1 in tumor tissues were 29.6 and 67.9%, respectively. Multivariate analysis suggested that tumor expression of PD-L1 was an independent prognostic factor and PD-L1 overexpression indicated a poor overall survival (OS) and disease-free survival (DFS). Taken together, we concluded that HMGB1 and HMGN1 secreted by cancer cells may relate to recruitment of tumor infiltrating lymphocytes (TILs) in HNSCC. PD-1/PD-L1 axis, rather than HMG proteins or CD8+ tumor-infiltrating lymphocytes, has a critical role in tumor immune microenvironment and could predict the outcome of HNSCC patients who received surgical resection.

Functional characterization of alternatively spliced GSN in head and neck squamous cell carcinoma

We have recently performed the characterization of alternative splicing events (ASEs) in head and neck squamous cell carcinoma, which allows dysregulation of protein expression common for cancer cells. Such analysis demonstrated a high ASE prevalence among tumor samples, including tumor-specific alternative splicing in the GSN gene.In vitro studies confirmed that overall expression of either ASE-GSN or wild-type GSN (WT-GSN) isoform inversely correlated with cell proliferation, whereas the high ratio of ASE-GSN to WT-GSN correlated with increased cellular invasion. Additionally, a change in expression of either isoform caused compensatory changes in expression of the other isoform. Our results suggest that the overall expression and the balance between GSN isoforms are mediating factors in proliferation, while increased overall expression of ASE-GSN is specific to cancer tissues. As a result, we propose ASE-GSN can serve not only as a biomarker of disease and disease progression, but also as a neoantigen for head and neck squamous cell carcinoma treatment, for which only a limited number of disease-specific targeted therapies currently exist.

The Role of Immunotherapy and Radiation Therapy in Tumor Chemosensitivity in Advanced Head and Neck Cancer

BACKGROUND Cancer is the second leading cause of death internationally, resulting in millions of deaths each year. While treatment in the past has heavily relied on surgery and radiotherapy, chemotherapy and immunotherapy are being increasingly utilized depending on disease presentation. CASE REPORT A 56-year-old male presented to the Emergency Department with a 3-week history of a rapidly enlarging left supraclavicular neck mass. Computed tomography scan revealed a 12×13 cm mass extending from the angle of the mandible to the supraclavicular area. A biopsy confirmed advanced stage squamous cell carcinoma of the head and neck. The patient was started on a chemotherapy regimen of docetaxel, cisplatin, and 5-fluorouracil (TCF). The tumor progressed through chemotherapy, which was switched to cetuximab; however, this therapy was discontinued after an anaphylactic reaction. Palliative radiation treatment was begun along with pembrolizumab. Pembrolizumab was continued, and after 9 cycles, the patient's cancer was almost in complete remission. Three months later, disease progression was once again noted with pembrolizumab treatment, which was subsequently discontinued. The patient was started on paclitaxel and carboplatin chemotherapy regimen as a last resort, despite failure of prior TCF treatment, and the patient responded, this time with complete remission in 4 months. CONCLUSIONS This case demonstrates a unique outcome in which a patient who previously was resistant to chemotherapy, later responded to chemotherapy after a trial of radiation therapy and immunotherapy. Immunotherapy may have a synergistic effect with radiation therapy and play a role in tumor sensitivity to chemotherapy in head and neck cancer treatment.

Low PD-L1 Expression Strongly Correlates with Local Recurrence in Epstein-Barr Virus-Positive Nasopharyngeal Carcinoma after Radiation-Based Therapy

The prognostic value of programmed death-ligand 1 (PD-L1) expression in nasopharyngeal carcinoma (NPC) is controversial, with previous studies showing conflicting results. Most NPCs in endemic areas are Epstein-Barr virus (EBV)-positive. Our aim was to evaluate the clinical significance of PD-L1 expression in EBV-positive NPC. We retrospectively analyzed PD-L1 expression on tumor cells (TCs) and immune cells (ICs) by immunohistochemistry in 208 EBV-positive NPC patients who underwent radiotherapy (203 with concurrent chemotherapy). The percentages of TCs and ICs expressing PD-L1 were evaluated respectively. There was a strong correlation between local recurrence and low PD-L1 expression on ICs (p = 0.0012), TCs (p = 0.013) or both (p = 0.000044), whereas all clinical parameters had no influence on local recurrence. Using multivariate analysis, low PD-L1 expression on ICs was an independent adverse prognostic factor (p = 0.0080; HR = 1.88; 95% CI = 1.18⁻3.00) for disease-free survival. High PD-L1 expression on both ICs and TCs was an independent favorable prognostic factor (p = 0.022; HR = 0.46; 95% CI = 0.24⁻0.89) for overall survival. We show for the first time that low PD-L1 expression on ICs and TCs strongly correlates with local recurrence in EBV-positive NPC patients after radiation-based therapy. A simple immunohistochemical study for PD-L1 can identify patients prone to local recurrence, and such patients might benefit from more aggressive treatment in future clinical trials.

Anti-cancer and analgesic effects of resolvin D2 in oral squamous cell carcinoma

Oral cancer is often painful and lethal. Oral cancer progression and pain may result from shared pathways that involve unresolved inflammation and elevated levels of pro-inflammatory cytokines. Resolvin D-series (RvDs) are endogenous lipid mediators derived from omega-3 fatty acids that exhibit pro-resolution and anti-inflammatory actions. These mediators have recently emerged as a novel class of therapeutics for diseases that involve inflammation; the specific roles of RvDs in oral cancer and associated pain are not defined. The present study investigated the potential of RvDs (RvD1 and RvD2) to treat oral cancer and alleviate oral cancer pain. We found down-regulated mRNA levels of GPR18 and GPR32 (which code for receptors RvD1 and RvD2) in oral cancer cells. Both RvD1 and RvD2 inhibited oral cancer proliferation in vitro. Using two validated mouse oral squamous cell carcinoma xenograft models, we found that RvD2, the more potent anti-inflammatory lipid mediator, significantly reduced tumor size. The mechanism of this action might involve suppression of IL-6, C-X-C motif chemokine 10 (CXCL10), and reduction of tumor necrosis. RvD2 generated short-lasting analgesia in xenograft cancer models, which coincided with decreased neutrophil infiltration and myeloperoxidase activity. Using a cancer supernatant model, we demonstrated that RvD2 reduced cancer-derived cytokines/chemokines (TNF-α, IL-6, CXCL10, and MCP-1), cancer mediator-induced CD11b⁺Ly6G^- myeloid cells, and nociception. We infer from our results that manipulation of the endogenous pro-resolution pathway might provide a novel approach to improve oral cancer and cancer pain treatment.

Nano-diamino-tetrac (NDAT) inhibits PD-L1 expression which is essential for proliferation in oral cancer cells

Programmed death-ligand 1 (PD-L1) is a critical regulator to defend tumor cells against immune surveillance. Thyroid hormone has been shown to induce PD-L1 expression in cancer cells. Its nano-particulated analogue, nano-diamino-tetrac (NDAT; Nanotetrac) is an anticancer/anti-angiogenic agent. In the current study, the inhibitory mechanism by which NDAT inhibited PD-L1 mRNA abundance and PD-L1 protein content in oral cancer cells was investigated. NDAT inhibited inducible PD-L1 expression and protein accumulation by the inhibition of activated ERK1/2 and PI3K. Knockdown PD-L1 also inhibited the proliferation of oral cancer cells which suggests that the inhibitory effect of NDAT on PD-L1 expression maybe is one of the critical mechanisms for NDAT-induced anti-proliferative effect in oral cancer cells.

Antibody-Mediated Therapy against HIV/AIDS: Where Are We Standing Now?

Acquired immunodeficiency syndrome (AIDS) cases are on the rise globally. To date, there is still no effective measure to eradicate the causative agent, human immunodeficiency virus (HIV). Highly active antiretroviral therapy (HAART) is being used in HIV/AIDS management, but it results in long-term medication and has major drawbacks such as multiple side effects, high cost, and increasing the generation rate of escape mutants. In addition, HAART does not control HIV-related complications, and hence more medications and further management are required. With this, other alternatives are urgently needed. In the past, small-molecule inhibitors have shown potent antiviral effects, and some of them are now being evaluated in clinical trials. The challenges in developing these small molecules for clinical use include the off-target effect, poor stability, and low bioavailability. On the other hand, antibody-mediated therapy has emerged as an important therapeutic modality for anti-HIV therapeutics development. Many antiviral antibodies, namely, broad neutralizing antibodies (bnAbs) against multiple strains of HIV, have shown promising effects in vitro and in animal studies; further studies are ongoing in clinical trials to evaluate their uses in clinical applications. This short review aims to discuss the current development of therapeutic antibodies against HIV and the challenges in adopting them for clinical use.

Harmonization of PD-L1 testing in oncology: a Canadian pathology perspective

Checkpoint inhibitors targeting the programmed cell death 1 protein (PD-1) and programmed cell death ligand 1 (PD-L1) are demonstrating promising efficacy and appear to be well tolerated in a number of tumour types. In non-small-cell lung cancer, head-and-neck squamous cell carcinoma, and urothelial carcinoma, outcomes appear particularly favourable in patients with high PD-L1 expression. However, assays for PD-L1 have been developed for individual agents, and they use different antibody clones, immunohistochemistry staining protocols, scoring algorithms, and cut-offs. Given that laboratories are unlikely to use multiple testing platforms, use of one PD-L1 assay in conjunction with a specific therapy will become impractical and could compromise treatment options. Methods to harmonize testing methods are therefore crucial to ensuring appropriate treatment selection. This paper focuses on lung, bladder, and head-and-neck cancer. It reviews and compares available PD-L1 testing methodologies, summarizes the literature about comparability studies to date, discusses future directions in personalized diagnostics, and provides a pathologist's perspective on PD-L1 testing in the Canadian laboratory setting.

PD-L1 expression in tumor tissue and peripheral blood of patients with oral squamous cell carcinoma

Background

Immune checkpoints like programmed cell death-1 (PD-1) and its ligand PD-L1 are involved in immune escape mechanisms of solid tumors including oral squamous cell carcinoma (OSCC). Inhibitors of the pathway are successfully used for treating especially advanced disease. However, the physiological relevance of PD-1/PD-L1-signaling in OSCC is insufficiently understood. The aim of the study was to analyze if PD-L1 expression in tumor tissue and peripheral blood samples of OSCC patients is associated with histomorphological tumor parameters and if PD-L1 expression in patients is different from controls.

Results

OSCC tumor specimens showed a significantly higher PD-L1 expression than oral mucosa controls (p < 0.001; upregulation more than 3-fold). Cross-tabulation revealed an association of increased expression of PD-L1 mRNA in tissue specimens with malignancy (p < 0.001).

OSCC cases with higher tumor grade and cases with lymph node metastases (N+) were significantly (p < 0.05) associated with increased PD-L1 expression in peripheral blood. Cross-tabulation revealed an significant association with lymph node metastases (N+) (p ≤ 0.002).

Materials and Methods

PD-L1 mRNA expression was analyzed in tumor specimens and corresponding samples of healthy oral mucosa and peripheral blood of 45 OSCC patients and 36 healthy control persons using RT-qPCR analysis. A Mann-Whitney U-test, a cut-off point analysis and a Chi-square test were carried out.

Conclusions

PD-L1 expression in OSCC could contribute to the immunosuppressive local tumor microenvironment. Increased malignant behavior (higher tumor grade, positive nodal status) might be associated with PD-L1 mediated systemic immune tolerance. Thus, PD-L1 expression in peripheral blood might be an indicator of the existence of metastatic disease (N+) in OSCC.

The cancer-testis antigen, sperm protein 17, a new biomarker and immunological target in head and neck squamous cell carcinoma

Head and Neck Squamous Cell Carcinoma is a deadly and locally aggressive malignancy that frequently portends a poor prognosis. Since current treatment modalities including surgery, chemotherapy and radiation are heavily debilitating and often result in recurrence intense efforts have been put into the development of novel less toxic and more lasting treatment strategies. Recently, immunotherapy has been proposed as a promising alternative that could potentially meet these requirements.

SP17 is a validated cancer-testis antigen in multiple myeloma, ovarian cancer and non-small cell lung cancer. We aim at studying SP17 expression in HNSCC and its immunogenicity as a possible future target for HNSCC therapeutic vaccines.

SP17 expression was evaluated in tissue specimens of HNSCC patients and controls. Moreover, SP17 immunogenicity was studied by generating autologous dendritic cells in vitro from the peripheral blood mononucleated cells of HNSCC patients and testing their ability to induce SP17 specific cytotoxic lymphocytes capable of killing autologous tumor cells in vitro. SP17specific immune responses were also evaluated in HNSCC patients as circulating anti-SP17 autoantibodies.

SP17 was expressed in HNSCC tissues of HNSCC patients. Autologous dendritic cells pulsed with SP17 antigen induced powerful SP17 MHC class-I restricted, perforin-dependent, cytotoxic T-cells capable of efficiently killing autologous tumor cells in vitro. SP17-specific autoantibodies were detectable in the serum of HNSCC patients irrespective of tumor site or TNM stage.

In conclusion, SP17 is an ideal immunotherapeutic target for HNSCC and a potential serological biomarker of the disease.