STAT1-Induced HLA Class I Upregulation Enhances Immunogenicity and Clinical Response to Anti-EGFR mAb Cetuximab Therapy in HNC Patients

Irradiated tumour cell-derived microparticles upregulate MHC-I expression in cancer cells via DNA double-strand break repair pathway

Radiotherapy (RT) is used for over 50 % of cancer patients and can promote adaptive immunity against tumour antigens. However, the underlying mechanisms remain unclear. Here, we discovered that RT induces the release of irradiated tumour cell-derived microparticles (RT-MPs), which significantly upregulate MHC-I expression on the membranes of non-irradiated cells, enhancing the recognition and killing of these cells by T cells. Mechanistically, RT-MPs induce DNA double-strand breaks (DSB) in tumour cells, activating the ATM/ATR/CHK1-mediated DNA repair signalling pathway, and upregulating MHC-I expression. Inhibition of ATM/ATR/CHK1 reversed RT-MP-induced upregulation of MHC-I. Furthermore, phosphorylation of STAT1/3 following the activation of ATM/ATR/CHK1 is indispensable for the DSB-dependent upregulation of MHC-I. Therefore, our findings reveal the role of RT-MP-induced DSBs and the subsequent DNA repair signalling pathway in MHC-I expression and provide mechanistic insights into the regulation of MHC-I expression after DSBs.

Immune escape of head and neck cancer mediated by the impaired MHC-I antigen presentation pathway

Tumor immune evasion is a hallmark of Head and Neck Cancers. The advent of immune checkpoint inhibitors (ICIs) in the first-line setting has transformed the management of these tumors. Unfortunately, the response rate of Head and Neck Squamous Cell Carcinomas (HNSCC) to ICIs is below 15%, regardless of the human papillomavirus (HPV) status, which might be partially related with impaired antigen presentation machinery (APM). Mechanistically, HNSCC cells are usually defective in the expression of MHC-I associated APM, while this transcriptional pathway is critical for the activation of tumor-killing effector T-cells. To specifically illuminate the phenomenon and seek for therapeutic strategies, this review summarizes the most recently identified role of genetic and functional dysregulation of the MHC-I pathway, specifically through changes at the genetic, epigenetic, post-transcriptional, and post-translational levels, which substantially contributes to HNSCC immune escape and ICI resistance. Several treatment modalities can be potentially exploited to restore APM signaling in tumors, which improves anti-tumor immunity through the activation of interferons, vaccines or rimantadine against HPV and the inhibition of EGFR, SHP-2, PI3K and MEK. Additionally, the combinatorial use of radiotherapy or cytotoxic agents with ICIs can synergize to potentiate APM signaling. Future directions would include further dissection of MHC-I related APM signaling in HNSCC and whether reversing this inhibition in combination with ICIs would elicit a more robust immune response leading to improved response rates in HNSCC. Therapeutic approaches to restore the MHC-I antigen presentation machinery in Head and Neck Cancer. (Red color texts represent the according strategies and the outcomes).

Phase Ib study of anti-EGFR antibody (SCT200) in combination with anti-PD-1 antibody (SCT-I10A) for patients with RAS/BRAF wild-type metastatic colorectal cancer

OBJECTIVE

This study evaluated the safety and efficacy of an anti-epidermal growth factor receptor (EGFR) antibody (SCT200) and an anti-programmed cell death 1 (PD-1) antibody (SCT-I10A) as third-line or subsequent therapies in patients with rat sarcoma viral oncogene (RAS)/v-raf murine sarcoma viral oncogene homolog B (BRAF) wild-type (wt) metastatic colorectal cancer (mCRC).

METHODS

We conducted a multicenter, open-label, phase Ib clinical trial. Patients with histologically confirmed RAS/BRAF wt mCRC with more than two lines of treatment were enrolled and treated with SCT-I10A and SCT200. The primary endpoints were the objective response rate (ORR) and safety. The secondary endpoints included disease control rate (DCR), progression-free survival (PFS), and overall survival (OS).

RESULTS

Twenty-one patients were enrolled in the study through January 28, 2023. The ORR was 28.57% and the DCR was 85.71% (18/21). The median PFS and OS were 4.14 and 12.84 months, respectively. The treatment-related adverse events (TRAEs) were tolerable. Moreover, compared with the monotherapy cohort from our previous phase I study evaluating SCT200 for RAS/BRAF wt mCRC in a third-line setting, no significant improvements in PFS and OS were observed in the combination group.

CONCLUSIONS

SCT200 combined with SCT-I10A demonstrated promising efficacy in previously treated RAS/BRAF wt mCRC patients with an acceptable safety profile. Further head-to-head studies with larger sample sizes are needed to validate whether the efficacy and safety of combined anti-EGFR and anti-PD-1 therapy are superior to anti-EGFR monotherapy in the third-line setting. (Registration No. NCT04229537).

Targeting MHC-I molecules for cancer: function, mechanism, and therapeutic prospects

The molecules of Major histocompatibility class I (MHC-I) load peptides and present them on the cell surface, which provided the immune system with the signal to detect and eliminate the infected or cancerous cells. In the context of cancer, owing to the crucial immune-regulatory roles played by MHC-I molecules, the abnormal modulation of MHC-I expression and function could be hijacked by tumor cells to escape the immune surveillance and attack, thereby promoting tumoral progression and impairing the efficacy of cancer immunotherapy. Here we reviewed and discussed the recent studies and discoveries related to the MHC-I molecules and their multidirectional functions in the development of cancer, mainly focusing on the interactions between MHC-I and the multiple participators in the tumor microenvironment and highlighting the significance of targeting MHC-I for optimizing the efficacy of cancer immunotherapy and a deeper understanding of the dynamic nature and functioning mechanism of MHC-I in cancer.

Sensitizing cancer cells to immune checkpoint inhibitors by microbiota-mediated upregulation of HLA class I

Recent data have shown that gut microbiota has a major impact on the clinical response to immune checkpoint inhibitors (ICIs) in the context of solid tumors. ICI-based therapy acts by unlocking cognate cytotoxic T lymphocyte (CTL) effector responses, and increased sensitivity to ICIs is due to an enhancement of patients' tumor antigen (TA)-specific CTL responses. Cancer clearance by TA-specific CTL requires expression of relevant TAs on cancer cells' HLA class I molecules, and reduced HLA class I expression is a common mechanism used by cancer cells to evade the immune system. Here, we show that metabolites released by bacteria, in particular, phytosphingosine, can upregulate HLA class I expression on cancer cells, sensitizing them to TA-specific CTL lysis in vitro and in vivo, in combination with immunotherapy. This effect is mediated by postbiotic-induced upregulation of NLRC5 in response to upstream MYD88-NF-κB activation, thus significantly controlling tumor growth.

Novel Insights of Anti-EGFR Therapy in HNSCC: Combined with Immunotherapy or Not?

PURPOSE OF REVIEW

The efficacy of anti-EGFR therapy is still unfavorable in recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) patients. Disorder of antitumor immunity and aberrantly expressed checkpoint biomarkers had been validated to involve anti-EGFR therapy tolerance and efficacy. Here we review the immunomodulation of anti-EGFR therapy in the tumor immune microenvironment (TIME) of HNSCC and assist clinicians in finding the potential strategies to rescue anti-EGFR tolerance therapy in the era of immunotherapy for HNSCC.

RECENT FINDINGS

Anti-EGFR therapy, especially cetuximab, was validated to induce the innate and adaptive immune responses of HNSCC patients. It is mainly through inducing natural killer (NK) cells mediating antibody-dependent cell-mediated cytotoxicity (ADCC), recruiting multiple tumor-infiltrating immune cells, and finally remodeling the TIME. Moreover, mountains of preclinical models and clinical trials revealed that combining anti-EGFR agents with immunotherapy could enhance the antitumor effectiveness in HNSCC. Anti-EGFR therapy may usher in another dawn in the treatment of patients with HNSCC through combination with immunotherapy. We offer an overview of the ongoing efforts to make out the immunomodulation of the EGFR pathway in both innate and adaptive immune responses; update the constant preclinical models and clinical trials for the combination of anti-EGFR and immunotherapy in HNSCC; and finally evaluate the efficacy and advantages of the combination therapeutic strategies in clinical use.

An Inflammatory Signature to Predict the Clinical Benefit of First-Line Cetuximab Plus Platinum-Based Chemotherapy in Recurrent/Metastatic Head and Neck Cancer

Epidermal growth factor receptor (EGFR) pathway has been shown to play a crucial role in several inflammatory conditions and host immune-inflammation status is related to tumor prognosis. This study aims to evaluate the prognostic significance of a four-gene inflammatory signature in recurrent/metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) patients treated with the EGFR inhibitor cetuximab plus chemotherapy. The inflammatory signature was assessed on 123 R/M HNSCC patients, enrolled in the multicenter trial B490 receiving first-line cetuximab plus platinum-based chemotherapy. The primary endpoint of the study was progression free survival (PFS), while secondary endpoints were overall survival (OS) and objective response rate (ORR). The patient population was subdivided into 3 groups according to the signature score groups. The four-genes-signature proved a significant prognostic value, resulting in a median PFS of 9.2 months in patients with high vs. 6.2 months for intermediate vs. 3.9 months for low values (p = 0.0016). The same findings were confirmed for OS, with median time of 18.4, 13.4, and 7.5 months for high, intermediate, and low values of the score, respectively (p = 0.0001). When ORR was considered, the signature was significantly higher in responders than in non-responders (p = 0.0092), reaching an area under the curve (AUC) of 0.65 (95% CI: 0.55–0.75). Our findings highlight the role of inflammation in the response to cetuximab and chemotherapy in R/M-HNSCC and may have translational implications for improving treatment selection.

Role of interferon-gamma (IFN-γ) and IFN-γ receptor 1/2 (IFNγR1/2) in regulation of immunity, infection, and cancer development: IFN-γ-dependent or independent pathway

IFN-γ, a soluble cytokine being produced by T lymphocytes, macrophages, mucosal epithelial cells, or natural killer cells, is able to bind to the IFN-γ receptor (IFNγR) and in turn activate the Janus kinase (JAK)-signal transducer and transcription protein (STAT) pathway and induce expression of IFN-γ-stimulated genes. IFN-γ is critical for innate and adaptive immunity and aberrant IFN-γ expression and functions have been associated with different human diseases. However, the IFN-γ/IFNγR signaling could be a double-edged sword in cancer development because the tissue microenvironments could determine its anti- or pro-tumorigenic activities. The IFNγR protein consists of two IFNγR1 and IFNγR2 chains, subunits of which play different roles under certain conditions. This review assessed IFNγR polymorphisms, expression and functions in development and progression of various human diseases in an IFN-γ-dependent or independent manner. This review also discussed tumor microenvironment, microbial infection, and vital molecules in the IFN-γ upstream signaling that might regulate IFNγR expression, drug resistance, and druggable strategy, to provide evidence for further application of IFNγR.

Major histocompatibility complex class I molecule expression by pancreatic cancer cells is regulated by activation and inhibition of the epidermal growth factor receptor

Pancreatic cancer is one of the deadliest neoplasms, with a dismal 5-year survival rate of only 10%. The ability of pancreatic cancer cells to evade the immune system hinders an anti-tumor response and contributes to the poor survival rate. Downregulation of major histocompatibility complex (MHC) class I cell-surface expression can aid in immune evasion by preventing endogenous tumor antigens from being presented to cytotoxic T cells. Earlier studies suggested that epidermal growth factor receptor (EGFR) signaling can decrease MHC class I expression on certain cancer cell types. However, even though erlotinib (a tyrosine kinase inhibitor that targets EGFR) is an approved drug for advanced pancreatic cancer treatment, the impact of EGFR inhibition or stimulation on pancreatic cancer cell MHC class I surface expression has not previously been analyzed. In this current study, we discovered that EGFR affects MHC class I mRNA and protein expression by human pancreatic cancer cell lines. We demonstrated that cell-surface MHC class I expression is downregulated upon EGFR activation, and the MHC class I level at the surface is elevated following EGFR inhibition. Furthermore, we found that EGFR associates with MHC class I molecules. By defining a role in pancreatic cancer cells for activated EGFR in reducing MHC class I expression and by revealing that EGFR inhibitors can boost MHC class I expression, our work supports further investigation of combined usage of EGFR inhibitors with immunotherapies against pancreatic cancer.

Temporal regulation of interferon signalling in human EndoC-βH1 cells

During the development of type 1 diabetes, interferons (IFN) are elaborated from islet-infiltrating immune cells and/or from virally infected β-cells. They act via specific receptors to increase, acutely, the phosphorylation of the transcription factors STAT1 and 2. However, the longer-term impacts of chronic IFN stimulation are poorly understood and were investigated in the current study. Human EndoC-βH1 cells were treated with IFNα, IFNγ or IFNλ either acutely (<2 h) or chronically (≥24 h) and STAT phosphorylation, expression and activity were assessed by Western blotting and transcriptional reporter assays. Exposure of β-cells to IFNα or IFNλ induced a swift increase in the phosphorylation of both STAT1 and STAT2, whereas IFNγ increased only pSTAT1. Over more extended periods (≥24 h), STAT phosphorylation declined but STAT1 and STAT2 expression were enhanced in a sustained manner. All IFNs stimulated ISRE transcriptional activity (but with different time courses), whereas GAS activity was responsive only to IFNγ. The re-addition of a second bolus of IFNα, 24 h after an initial dose, failed to cause renewed STAT1/2 phosphorylation. By contrast, when IFNγ was added 24 h after exposure to IFNα, rapid STAT1 phosphorylation was re-initiated. Exposure of β-cells to IFNs leads to rapid, transient, STAT phosphorylation and to slower and more sustained increases in total STAT1/2 levels. The initial phosphorylation response is accompanied by marked desensitisation to the cognate agonist. Together, the results reveal that the response of β-cells to IFNs is regulated both temporally and quantitatively to achieve effective signal integration.

Biological Characteristics and Clinical Significance of Soluble PD-1/PD-L1 and Exosomal PD-L1 in Cancer

The immune checkpoint pathway consisting of the cell membrane-bound molecule programmed death protein 1 (PD-1) and its ligand PD-L1 has been found to mediate negative regulatory signals that effectively inhibit T-cell proliferation and function and impair antitumor immune responses. Considerable evidence suggests that the PD-1/PD-L1 pathway is responsible for tumor immune tolerance and immune escape. Blockage of this pathway has been found to reverse T lymphocyte depletion and restore antitumor immunity. Antagonists targeting this pathway have shown significant clinical activity in specific cancer types. Although originally identified as membrane-type molecules, several other forms of PD-1/PD-L1 have been detected in the blood of cancer patients, including soluble PD-1/PD-L1 (sPD-1/sPD-L1) and exosomal PD-L1 (exoPD-L1), increasing the composition and functional complications of the PD-1/PD-L1 signaling pathway. For example, sPD-1 has been shown to block the PD-1/PD-L immunosuppressive pathway by binding to PD-L1 and PD-L2, whereas the role of sPD-L1 and its mechanism of action in cancer remain unclear. In addition, many studies have investigated the roles of exoPD-L1 in immunosuppression, as a biomarker for tumor progression and as a predictive biomarker for response to immunotherapy. This review describes the molecular mechanisms underlying the generation of sPD-1/sPD-L1 and exoPD-L1, along with their biological activities and methods of detection. In addition, this review discusses the clinical importance of sPD-1/sPD-L1 and exoPD-L1 in cancer, including their predictive and prognostic roles and the effects of treatments that target these molecules.

Human Leukocyte Antigen Class I Antigen-Processing Machinery Upregulation by Anticancer Therapies in the Era of Checkpoint Inhibitors: A Review

IMPORTANCE

Although typically impressive, objective responses to immune checkpoint inhibitors (ICIs) occur in only 12.5% of patients with advanced cancer. The majority of patients do not respond due to cell-intrinsic resistance mechanisms, including human leukocyte antigen (HLA) class I antigen-processing machinery (APM) defects. The APM defects, which have a negative effect on neoantigen presentation to cytotoxic T lymphocytes (CTLs), are present in the majority of malignant tumors. These defects are caused by gene variations in less than 25% of cases and by dysregulated signaling and/or epigenetic changes in most of the remaining cases, making them frequently correctable. This narrative review summarizes the growing clinical evidence that chemotherapy, targeted therapies, and, to a lesser extent, radiotherapy can correct HLA class I APM defects in cancer cells and improve responses to ICIs.

OBSERVATIONS

Most chemotherapeutics enhance HLA class I APM component expression and function in cancer cells, tumor CTL infiltration, and responses to ICIs in preclinical and clinical models. Despite preclinical evidence, radiotherapy does not appear to upregulate HLA class I expression in patients and does not enhance the efficacy of ICIs in clinical settings. The latter findings underscore the need to optimize the dose and schedule of radiation and timing of ICI administration to maximize their immunogenic synergy. By increasing DNA and chromatin accessibility, epigenetic agents (histone deacetylase inhibitors, DNA methyltransferase inhibitors, and EZH2 inhibitors) enhance HLA class I APM component expression and function in many cancer types, a crucial contributor to their synergy with ICIs in patients. Furthermore, epidermal growth factor receptor (EGFR) inhibitors and BRAF/mitogen-activated protein kinase kinase inhibitors are effective at upregulating HLA class I expression in EGFR- and BRAF-variant tumors, respectively; these changes may contribute to the clinical responses induced by these inhibitors in combination with ICIs.

CONCLUSIONS AND RELEVANCE

This narrative review summarizes evidence indicating that chemotherapy and targeted therapies are effective at enhancing HLA class I APM component expression and function in cancer cells. The resulting increased immunogenicity and recognition and elimination of cancer cells by cognate CTLs contributes to the antitumor activity of these therapies as well as to their synergy with ICIs.

Mechanisms of MHC-I Downregulation and Role in Immunotherapy Response

Immunotherapy has become a key therapeutic strategy in the treatment of many cancers. As a result, research efforts have been aimed at understanding mechanisms of resistance to immunotherapy and how anti-tumor immune response can be therapeutically enhanced. It has been shown that tumor cell recognition by the immune system plays a key role in effective response to T cell targeting therapies in patients. One mechanism by which tumor cells can avoid immunosurveillance is through the downregulation of Major Histocompatibility Complex I (MHC-I). Downregulation of MHC-I has been described as a mechanism of intrinsic and acquired resistance to immunotherapy in patients with cancer. Depending on the mechanism, the downregulation of MHC-I can sometimes be therapeutically restored to aid in anti-tumor immunity. In this article, we will review current research in MHC-I downregulation and its impact on immunotherapy response in patients, as well as possible strategies for therapeutic upregulation of MHC-I.

HLA class I antigen processing machinery defects in antitumor immunity and immunotherapy

Human leukocyte antigen (HLA) class I antigen-processing machinery (APM) plays a crucial role in the synthesis and expression of HLA class I tumor antigen-derived peptide complexes; the latter mediate the recognition and elimination of malignant cells by cognate T cells. Defects in HLA class I APM component expression and/or function are frequently found in cancer cells, providing them with an immune escape mechanism that has relevance in the clinical course of the disease and in the response to T-cell-based immunotherapy. The majority of HLA class I APM defects (>75%) are caused by epigenetic mechanisms or dysregulated signaling and therefore can be corrected by strategies that counteract the underlying mechanisms. Their application in oncology is likely to improve responses to T-cell-based immunotherapies, including checkpoint inhibition.

Soluble B7-CD28 Family Inhibitory Immune Checkpoint Proteins and Anti-Cancer Immunotherapy

Co-inhibitory B7-CD28 family member proteins negatively regulate T cell responses and are extensively involved in tumor immune evasion. Blockade of classical CTLA-4 (cytotoxic T lymphocyte-associated antigen-4) and PD-1 (programmed cell death protein-1) checkpoint pathways have become the cornerstone of anti-cancer immunotherapy. New inhibitory checkpoint proteins such as B7-H3, B7-H4, and BTLA (B and T lymphocyte attenuator) are being discovered and investigated for their potential in anti-cancer immunotherapy. In addition, soluble forms of these molecules also exist in sera of healthy individuals and elevated levels are found in chronic infections, autoimmune diseases, and cancers. Soluble forms are generated by proteolytic shedding or alternative splicing. Elevated circulating levels of these inhibitory soluble checkpoint molecules in cancer have been correlated with advance stage, metastatic status, and prognosis which underscore their broader involvement in immune regulation. In addition to their potential as biomarker, understanding their mechanism of production, biological activity, and pathological interactions may also pave the way for their clinical use as a therapeutic target. Here we review these aspects of soluble checkpoint molecules and elucidate on their potential for anti-cancer immunotherapy.

Tyrosine Kinase Inhibitors Stimulate HLA Class I Expression by Augmenting the IFNγ/STAT1 Signaling in Hepatocellular Carcinoma Cells

Combination treatment with tyrosine kinase inhibitors (TKIs) and immunotherapies has shown efficacy in the treatment of multiple cancers, but the immunomodulatory effect of TKIs on the tumor cell phenotype remains unknown in hepatocellular carcinoma (HCC). Given that human lymphocyte antigen class I (HLA-I) is essential for tumor antigen presentation and subsequent antitumor immunity, we examined the effects of regorafenib, as well as other TKIs (sorafenib, lenvatinib and cabozantinib) on HLA-I expression in HCC cell lines. Regorafenib increased cell surface HLA-I and β2-microglobulin protein expression in the presence of interferon γ (IFNγ). The expressions of various genes associated with the HLA-I antigen processing pathway and its transcriptional regulators were also upregulated by regorafenib. Furthermore, we found that regorafenib had an activating effect on signal transducers and activators of transcription 1 (STAT1), and that regorafenib-induced HLA-I expression was dependent on the augmented IFNγ/STAT1 signaling pathway. Trametinib, an inhibitor of the extracellular signal-regulated kinase (ERK) kinase MEK, also activated IFNγ/STAT1 signaling and increased HLA-I expression, whereas the phosphatidylinositol 3-kinase (PI3K) inhibitor buparlisib did not. Given that regorafenib directly inhibits Raf/MEK/ERK signaling, the downregulation of the MEK/ERK pathway appears to be one of the mechanisms by which regorafenib promotes STAT1 activation. Sorafenib, lenvatinib, and cabozantinib also showed the same effects as regorafenib, while regorafenib had most potent effects on HLA-I expression, possibly dependent on its stronger inhibitory activity against the MEK/ERK pathway. These results support the clinical combination of TKIs with immunotherapy for the treatment of HCC.

Immune deserts in head and neck squamous cell carcinoma: A review of challenges and opportunities for modulating the tumor immune microenvironment

Immunotherapy revolutionized cancer treatment but has yet to elicit durable responses in the majority of patients with head and neck squamous cell carcinoma (HNSCC). HNSCC is generally characterized by a high tumor mutational burden, which has translated to a large neoantigen load that could prime the immune system to recognize and eliminate malignant cells. Studies are increasingly showing, however, that HNSCC is an "immune desert" tumor that can hijack multiple parts of the tumor immunity cycle in order to evade immune recognition and suppress immune system activation. Herein we will review how HNSCC tumors modulate their architecture, cellular composition, and cytokine milieu to maximize immunosuppression; as well as relevant therapeutic opportunities and emerging issues facing the field of HNSCC immuno-oncology.

Virus-specific T cells for malignancies - then, now and where to?

Purpose of Review

Virus-associated malignancies are a global health burden, constituting 10-12% of cancers worldwide. As these tumors express foreign viral antigens that can elicit specific T cell responses, virus-directed immunotherapies are a promising treatment strategy. Specifically, adoptive cell transfer of virus-specific T cells (VSTs) has demonstrated the potential to eradicate cancers associated with certain viruses.

Recent Findings

Initial studies in 1990s first showed that VSTs specific for the Epstein-Barr virus (EBVSTs) can induce complete remissions in patients with post-transplant lymphoproliferative disease. Since then, studies have validated the specificity and safety of VSTs in multiple lymphomas and solid malignancies. However, challenges remain to optimize this platform for widespread use, including enhancing potency and persistence, overcoming the immunosuppressive tumor microenvironment, and streamlining manufacturing processes that comply with regulatory requirements.

Summary

This review focuses on data from clinical trials evaluating VSTs directed against three viruses (EBV, HPV and MCPyV), as well as recent preclinical and clinical advances, and potential future directions.

Role of epidermal growth factor receptor inhibitor-induced interferon pathway signaling in the head and neck squamous cell carcinoma therapeutic response

BACKGROUND

Epidermal growth factor receptor (EGFR) is frequently amplified or overexpressed in head and neck squamous cell carcinoma (HNSCC) and is a clinically validated target for the therapeutic antibody, cetuximab, in the management of this cancer. The degree of response to EGFR inhibitors measured by tumor shrinkage varies widely among HNSCC patients, and the biological mechanisms that underlie therapeutic heterogeneity amongst HNSCC patients remain ill-defined.

METHODS

EGFR-dependent human and murine HNSCC cell lines were treated with the EGFR/ERBB inhibitors, gefitinib and AZD8931, and submitted to RNAseq, GSEA, and qRT-PCR. Conditioned media was analyzed by ELISA and Luminex assays. Murine HNSCC tumors were stained for T cell markers by immunofluorescence. Primary HSNCC patient specimens treated with single agent cetuximab were stained with Vectra multispectral immunofluorescence.

RESULTS

The transcriptional reprogramming response to EGFR/ERBB-specific TKIs was measured in a panel of EGFR-dependent human HNSCC cell lines and interferon (IFN) α and γ responses identified as top-ranked TKI-induced pathways. Despite similar drug sensitivity, responses among 7 cell lines varied quantitatively and qualitatively, especially regarding the induced chemokine and cytokine profiles. Of note, the anti-tumorigenic chemokine, CXCL10, and the pro-tumorigenic factor, IL6, exhibited wide-ranging and non-overlapping induction. Similarly, AZD8931 exerted potent growth inhibition, IFNα/IFNγ pathway activation, and CXCL10 induction in murine B4B8 HNSCC cells. AZD8931 treatment of immune-competent mice bearing orthotopic B4B8 tumors increased CD8 + T cell content and the therapeutic response was abrogated in nu/nu mice relative to BALB/c mice. Finally, Vectra 3.0 analysis of HNSCC patient tumors prior to and after 3-4 weeks of single agent cetuximab treatment revealed increased CD8 + T cell content in specimens from patients exhibiting a therapeutic response relative to non-responders.

CONCLUSIONS

The findings reveal heterogeneous, tumor cell-intrinsic, EGFR/ERBB inhibitor-induced IFN pathway activation in HNSCC and suggest that individual tumor responses to oncogene-targeted agents are a sum of direct growth inhibitory effects and variably-induced participation of host immune cells.

Combinations using checkpoint blockade to overcome resistance

The advent of immunotherapy for cancer represented a paradigm shift in the treatment approach of neoplasia. Immune-checkpoint inhibitors (ICIs) were demonstrated to significantly improve outcomes, including overall survival across several cancer types, with yearly-durable responses. Nevertheless, many patients derive minor or no benefit with immune checkpoint (IC)-blockade, including patients with cancer types traditionally considered immunogenic. Combination strategies of ICIs with chemotherapy, radiotherapy, targeted therapies or other immunotherapy compounds have been conceived in order to boost the immune-responses and potentially overcome resistance to ICIs. This review focuses on mechanisms underlying resistance to IC-blockade and provides an overview of potential advantages and limitations of combination strategies currently under investigation.

Discordant Responses Between Primary Head and Neck Tumors and Nodal Metastases Treated With Neoadjuvant Nivolumab: Correlation of Radiographic and Pathologic Treatment Effect

PD-1 blockade represents a promising treatment in patients with head and neck squamous cell carcinoma (HNSCC). We analyzed results of a neoadjuvant randomized window-of-opportunity trial of nivolumab plus/minus tadalafil to investigate whether immunotherapy-mediated treatment effects vary by site of involvement (primary tumor, lymph nodes) and determine how radiographic tumor shrinkage correlates with pathologic treatment effect.

Soluble PD-1: Predictive, Prognostic, and Therapeutic Value for Cancer Immunotherapy

Programmed death protein 1 (PD-1) interaction with PD-L1 deliver immunosuppressive environment for tumor growth, and its blockade with directed monoclonal antibodies (anti-PD-1/anti-PD-L1) has shown remarkable clinical outcome. Lately, their soluble counterparts, sPD-1 and sPD-L1, have been detected in plasma, and elevated levels have been associated with advanced disease, clinical stages, and worst prognosis for cancer patients. Elevated plasma levels of sPD-L1 have been correlated with worst prognosis in several studies and has displayed a persistent outlook. On the other hand, sPD-1 levels have been inconsistent in their predictive and prognostic ability. Pretherapeutic higher sPD-1 plasma levels have shown to predict advanced disease state and to a lesser extent worst prognosis. Any increase in sPD-1 plasma level post therapeutically have been correlated with improved survival for various cancers. In vitro and in vivo studies have shown sPD-1 ability to bind PD-L1 and PD-L2 and block PD-1/PD-L1 interaction. Local delivery of sPD-1 in cancer tumor microenvironment through local gene therapy have demonstrated an increase in tumor specific CD8+ T cell immunity and tumor growth reduction. It had also exhibited enhancement of T cell immunity induced by vaccination and other gene therapeutic agents. Furthermore, it may also lessen the inhibitory effect of circulating sPD-L1 and enhance the effects of mAb-based immunotherapy. In this review, we highlight various aspects of sPD-1 role in cancer prediction, prognosis, and anti-cancer immunity, as well as, its therapeutic value for local gene therapy or systemic immunotherapy in blocking the PD-1 and PD-L1 checkpoint interactions.

Neoantigen prediction and computational perspectives towards clinical benefit: recommendations from the ESMO Precision Medicine Working Group

BACKGROUND

The use of next-generation sequencing technologies has enabled the rapid identification of non-synonymous somatic mutations in cancer cells. Neoantigens are mutated peptides derived from somatic mutations not present in normal tissues that may result in the presentation of tumour-specific peptides capable of eliciting antitumour T-cell responses. Personalised neoantigen-based cancer vaccines and adoptive T-cell therapies have been shown to prime host immunity against tumour cells and are under clinical trial development. However, the optimisation and standardisation of neoantigen identification, as well as its delivery as immunotherapy are needed to increase tumour-specific T-cell responses and, thus, the clinical efficacy of current cancer immunotherapies.

METHODS

In this recommendation article, launched by the European Society for Medical Oncology (ESMO), we outline and discuss the available framework for neoantigen prediction and present a systematic review of the current scientific evidence.

RESULTS

A number of computational pipelines for neoantigen prediction are available. Most of them provide peptide major histocompatibility complex (MHC) binding affinity predictions, but more recent approaches incorporate additional features like variant allele fraction, gene expression, and clonality of mutations. Neoantigens can be predicted in all cancer types with high and low tumour mutation burden, in part by exploiting tumour-specific aberrations derived from mutational frameshifts, splice variants, gene fusions, endogenous retroelements and other tumour-specific processes that could yield more potently immunogenic tumour neoantigens. Ongoing clinical trials will highlight those cancer types and combinations of immune therapies that would derive the most benefit from neoantigen-based immunotherapies.

CONCLUSIONS

Improved identification, selection and prioritisation of tumour-specific neoantigens are needed to increase the scope of benefit from cancer vaccines and adoptive T-cell therapies. Novel pipelines are being developed to resolve the challenges posed by high-throughput sequencing and to predict immunogenic neoantigens.

MHC Class I Downregulation in Cancer: Underlying Mechanisms and Potential Targets for Cancer Immunotherapy

In recent years, major advances have been made in cancer immunotherapy. This has led to significant improvement in prognosis of cancer patients, especially in the hematological setting. Nonetheless, translation of these successes to solid tumors was found difficult. One major mechanism through which solid tumors can avoid anti-tumor immunity is the downregulation of major histocompatibility complex class I (MHC-I), which causes reduced recognition by- and cytotoxicity of CD8⁺ T-cells. Downregulation of MHC-I has been described in 40-90% of human tumors, often correlating with worse prognosis. Epigenetic and (post-)transcriptional dysregulations relevant in the stabilization of NFkB, IRFs, and NLRC5 are often responsible for MHC-I downregulation in cancer. The intrinsic reversible nature of these dysregulations provides an opportunity to restore MHC-I expression and facilitate adaptive anti-tumor immunity. In this review, we provide an overview of the mechanisms underlying reversible MHC-I downregulation and describe potential strategies to counteract this reduction in MHC-I antigen presentation in cancer.

Real-world assessment of afatinib for patients with EGFR-positive non-small cell lung cancer

Introduction Afatinib is used to treat patients with advanced non-small cell lung cancer (NSCLC) harboring common EGFR mutations; however, the clinicopathological factors that predict this drug's effectiveness in real-world settings remain unclear. We therefore evaluated the effectiveness of afatinib in such patients and assessed potential prognostic factors. Methods We retrospectively investigated patients with NSCLC who received first-line afatinib between July 2014 and August 2018. Variables (including sex, age, performance status, neutrophil-to-lymphocyte ratio, EGFR genotype, smoking status, clinical stage prior to treatment [stage IV vs.. postoperative recurrence], presence or absence of brain metastases, body surface area, any afatinib dose reductions, and afatinib starting dose [40 vs.. 20 or 30 mg]) were subjected to a Cox proportional hazards regression model to estimate progression-free survival (PFS). Results Forty-eight patients with a median age of 67 years were included; the objective response rate was 62.5% (30 patients). The median PFS was 14.1 months; the PFS periods were 11.8 and 15.9 months for patients receiving 40 mg versus 20-30 mg of afatinib (P = 0.41), respectively, and were 14.5 and 13.8 months for patients who required afatinib dose reduction and those who did not, respectively (P = 0.80). The PFS tended to be longer in patients without brain metastases (albeit not significantly). Ultimately, no significant predictive values for PFS were identified. Conclusions Afatinib is effective for patients with NSCLC harboring common EGFR mutations irrespective of their clinicopathological backgrounds. A direct comparison of afatinib and osimertinib in treatment-naïve patients is warranted to determine the optimal standard of care.

TLR4 activation leads to anti-EGFR therapy resistance in head and neck squamous cell carcinoma

Epidermal growth factor receptor (EGFR) is highly expressed in head and neck squamous cell carcinoma (HNSCC) and related to cancer progression. The resistance to anti-EGFR therapy remains a major clinical problem in HNSCC. In this study, we found that TOLL-like receptor 4 (TLR4) was highly expressed in 50% of EGFR overexpressed HNSCC biopsies, which correlated to worse prognosis in patients. In HNSCC cell lines, activation of TLR4 reversed cetuximab-induced the inhibition of proliferation, migration and invasion. LPS induced of TLR4 signaling was potentiated under cetuximab treatment, showing increased activation of downstream NF-κB and MAPK pathways. Accordingly, cetuximab treatment also increased expression of TNF-α, COX2, and other molecules involved in TLR4 induced tumor inflammation. Mechanistically, we found inhibition of EGFR by cetuximab led to decreased phosphorylation of Src and sequentially Src-medicated activation of Cbl-b. This inhibited Cbl-b-mediated degradation of the key TLR4 adaptor protein MyD88 and activated TLR4 signaling. TLR4 or MyD88 overexpressed CAL27 and SCC4 cells grew faster and were more resistant to cetuximab and gefitinib both in vitro and in vivo. Out study delineates a crosstalk between EGFR and TLR4 pathways and identified TLR4 as a potential biomarker as well as a therapeutic target in overcoming the resistance to anti-EGFR therapy of HNSCC.

Overcoming malignant cell-based mechanisms of resistance to immune checkpoint blockade antibodies

Traditional cancer treatment approaches have focused on surgery, radiation therapy, and cytotoxic chemotherapy. However, with rare exceptions, metastatic cancers were considered to be incurable by traditional therapy. Over the past 20 years a fourth modality - immunotherapy - has emerged as a potentially curative approach for patients with advanced metastatic cancer. However, in many patients cancer "finds a way" to evade the anti-tumor effects of immunotherapy. Immunotherapy resistance mechanisms can be employed by both cancer cells and the non-cancer elements of tumor microenvironment. This review focuses on the resistance mechanisms that are specifically mediated by cancer cells. In order to extend the impact of immunotherapy to more patients and across all cancer types, and to inhibit the development of acquired resistance, the underlying biology driving immune escape needs to be better understood. Elucidating mechanisms of immune escape may shed light on new therapeutic targets, and lead to successful combination therapeutic strategies.

ALK and RET Inhibitors Promote HLA Class I Antigen Presentation and Unmask New Antigens within the Tumor Immunopeptidome

T-cell immunotherapies are often thwarted by the limited presentation of tumor-specific antigens abetted by the downregulation of human leukocyte antigen (HLA). We showed that drugs inhibiting ALK and RET produced dose-related increases in cell-surface HLA in tumor cells bearing these mutated kinases in vitro and in vivo, as well as elevated transcript and protein expression of HLA and other antigen-processing machinery. Subsequent analysis of HLA-presented peptides after ALK and RET inhibitor treatment identified large changes in the immunopeptidome with the appearance of hundreds of new antigens, including T-cell epitopes associated with impaired peptide processing (TEIPP) peptides. ALK inhibition additionally decreased PD-L1 levels by 75%. Therefore, these oncogenes may enhance cancer formation by allowing tumors to evade the immune system by downregulating HLA expression. Altogether, RET and ALK inhibitors could enhance T-cell-based immunotherapies by upregulating HLA, decreasing checkpoint blockade ligands, and revealing new, immunogenic, cancer-associated antigens.

STAT1 inhibits T-cell exhaustion and myeloid derived suppressor cell accumulation to promote antitumor immune responses in head and neck squamous cell carcinoma

Cancers of the oral cavity remain the sixth most diagnosed cancer worldwide, with high rates of recurrence and mortality. We determined the role of STAT1 during oral carcinogenesis using two orthotopic models in mice genetically deficient for Stat1. Metastatic (LY2) and nonmetastatic (B4B8) head and neck squamous cell carcinoma (HNSCC) cell lines were injected into the oral cavity of Stat1 deficient (Stat1^-/- ) and Stat1 competent (Stat1^+/+ ) mice. Stat1^-/- mice displayed increased tumor growth and metastasis compared to Stat1^+/+ mice. Mechanistically, Stat1^-/- mice displayed impaired CD4+ and CD8+ T-cell expansion compared to Stat1^+/+ mice. This was associated with enhanced T-cell exhaustion, and severely attenuated T-cell antitumor effector responses including reduced expression of IFN-γ and perforin at the tumor site. Interestingly, tumor necrosis factor (TNF)-α production by T cells in tumor-bearing mice was suppressed by Stat1 deficiency. This deficiency in T-cell expansion and functional responses in mice was linked to PD-1 and CD69 overexpression in T cells of Stat1^-/- mice. In contrast, we observed increased accumulation of CD11b+ Ly6G+ myeloid derived suppressor cells in tumors, draining lymph nodes, spleens and bone marrow of tumor-bearing Stat1^-/- mice, resulting in a protumorigenic microenvironment. Our data demonstrates that STAT1 is an essential mediator of the antitumor response through inhibition of myeloid derived suppressor cell accumulation and promotion of T-cell mediated immune responses in murine head and neck squamous cell carcinoma. Selective induction of STAT1 phosphorylation in HNSCC patients could potentially improve oral tumor outcomes and response to therapy.

Distinguishing Features of Cetuximab and Panitumumab in Colorectal Cancer and Other Solid Tumors

Cetuximab and panitumumab are two distinct monoclonal antibodies (mAbs) targeting the epidermal growth factor receptor (EGFR), and both are widely used in combination with chemotherapy or as monotherapy to treat patients with RAS wild-type metastatic colorectal cancer. Although often considered interchangeable, the two antibodies have different molecular structures and can behave differently in clinically relevant ways. More specifically, as an immunoglobulin (Ig) G1 isotype mAb, cetuximab can elicit immune functions such as antibody-dependent cell-mediated cytotoxicity involving natural killer cells, T-cell recruitment to the tumor, and T-cell priming via dendritic cell maturation. Panitumumab, an IgG2 isotype mAb, does not possess these immune functions. Furthermore, the two antibodies have different binding sites on the EGFR, as evidenced by mutations on the extracellular domain that can confer resistance to one of the two therapeutics or to both. We consider a comparison of the properties of these two antibodies to represent a gap in the literature. We therefore compiled a detailed, evidence-based educational review of the known molecular, clinical, and functional differences between the two antibodies and concluded that they are distinct therapeutic agents that should be considered individually during treatment planning. Available data for one agent can only partly be extrapolated to the other. Looking to the future, the known immune activity of cetuximab may provide a rationale for this antibody as a combination partner with investigational chemotherapy plus immunotherapy regimens for colorectal cancer.

Window of opportunity trials in head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) has a large global burden of disease and poor survival outcomes. Recent targeted therapies and immunotherapies have been explored in HNSCC, but there has been limited translation to clinical practice outside of recurrent or metastatic cases. Window of opportunity settings, where novel agents are administered between cancer diagnosis and planned definitive therapy, have begun to be employed in HNSCC. Tumor tissue biopsies are obtained at diagnosis and after the investigation treatment, along with other biospecimens and radiographic exams. Thus, this study design can characterize the safety profiles, pharmacodynamics, and initial tumor responses to novel therapies in a treatment-naïve subject. Early window studies have also identified potential biomarkers to predict sensitivity or resistance to treatments. However, these early investigations have revealed multiple challenges associated with this trial design. In this review, we discuss recent window of opportunity trials in HNSCC and how they inform design considerations for future studies.

Immunogenomic correlates of response to cetuximab monotherapy in head and neck squamous cell carcinoma

BACKGROUND

Mechanisms of resistance to immune-modulating cancer treatments are poorly understood. Using a novel cohort of patients with head and neck squamous cell carcinoma (HNSCC), we investigated mechanisms of immune escape from epidermal growth factor receptor-specific monoclonal antibody (mAb) therapy.

METHODS

HNSCC tumors (n = 20) from a prospective trial of neoadjuvant cetuximab monotherapy underwent whole-exome sequencing. Expression of killer-cell immunoglobulin-like receptor (KIR) and human leukocyte antigen-C (HLA-C) and the effect of KIR blockade were assessed in HNSCC cell lines.

RESULTS

Nonresponders to cetuximab had an increased rate of mutations in HLA-C compared to responders and HNSCC tumors (n = 528) in The Cancer Genome Atlas (P < 0.00001). In vitro, cetuximab-activated natural killer (NK) cells induced upregulation of HLA-C on HNSCC cells (P < 0.01) via interferon gamma. Treatment of NK cells with the anti-KIR mAb lirilumab increased killing of HNSCC cells (P < 0.001).

CONCLUSIONS

Alterations in HLA-C may provide a mechanism of immune evasion through disruption of NK activation.

EGFR-targeted therapy alters the tumor microenvironment in EGFR-driven lung tumors: Implications for combination therapies

Immune checkpoint inhibitors targeting the programmed cell death receptor/ligand 1 (PD-1/PD-L1) pathway have profoundly improved the clinical management of non-small-cell lung cancer (NSCLC). Nevertheless, the superiority of single-agent PD-1/PD-L1 inhibitors in pretreated EGFR mutant patients has turned out to be moderate. One proposed mechanism for poor response to immune checkpoint inhibitors is an immunosuppressive tumor microenvironment. Therefore, we utilized two autochthonous EGFR-driven lung tumor models to investigate dynamic microenvironmental responses to EGFR-TKI treatment. We observed that at an early stage, sensitive EGFR-TKIs caused obvious tumor shrinkage accompanied by increased cytotoxic CD8⁺ T cells and dendritic cells, eradication of Foxp3⁺ Tregs, and inhibition of M2-like polarization of macrophages. However, the tumor microenvironmental changes that may be most beneficial for combination treatment with immune-mediated anticancer approaches were only temporary and disappeared as treatment continued. Meanwhile, the level of myeloid-derived suppressor cells (MDSCs), particularly mononuclear MDSCs, was consistently elevated throughout the treatment. Analysis of inflammatory factors in serum showed that EGFR-TKIs increased the levels of IL-10 and CCL-2. Our study systematically analyzed dynamic changes in tumor microenvironments responding to EGFR-TKIs in vivo. The results have implications for combination therapy using EGFR-TKIs. The optimal sequence of the treatment and strategies that modulate the tumor microenvironment to a state that may favor antitumor immune responses need to be considered when designing clinical trials.

Turning the corner on therapeutic cancer vaccines

Recent advances in several areas are rekindling interest and enabling progress in the development of therapeutic cancer vaccines. These advances have been made in target selection, vaccine technology, and methods for reversing the immunosuppressive mechanisms exploited by cancers. Studies testing different tumor antigens have revealed target properties that yield high tumor versus normal cell specificity and adequate immunogenicity to affect clinical efficacy. A few tumor-associated antigens, normal host proteins that are abnormally expressed in cancer cells, have been demonstrated to serve as good targets for immunotherapies, although many do not possess the needed specificity or immunogenicity. Neoantigens, which arise from mutated proteins in cancer cells, are truly cancer-specific and can be highly immunogenic, though the vast majority are unique to each patient's cancer and thus require development of personalized therapies. Lessons from previous cancer vaccine expeditions are teaching us the type and magnitude of immune responses needed, as well as vaccine technologies that can achieve these responses. For example, we are learning which vaccine approaches elicit the potent, balanced, and durable CD4 plus CD8 T cell expansion necessary for clinical efficacy. Exploration of interactions between the immune system and cancer has elucidated the adaptations that enable cancer cells to suppress and evade immune attack. This has led to breakthroughs in the development of new drugs, and, subsequently, to opportunities to combine these with cancer vaccines and dramatically increase patient responses. Here we review this recent progress, highlighting key steps that are bringing the promise of therapeutic cancer vaccines within reach.

Immune response characterization of endometrial cancer

Background

The comprehensive characterization and prognostic relevance of immune activation in endometrial cancer remain largely unknown.

Results

We systematically reported a subset of endometrioid-type endometrial cancer characterized by multifaceted immune features such as low tumor purity, high leukocyte percentage, and striking CD8 lymphocytic infiltration with anti-tumor efficacy along with marked upregulation of immunosuppressive gene markers. We also showed that genes whose expression was significantly correlated with better survival were significantly enriched in the immune-related signaling pathways, suggesting that tumor-infiltrating lymphocytes give rise to a favorable prognosis in endometrial cancer. Furthermore, we showed that immune cell recruitment in this subset of tumors is likely due to the transcriptional activation of the STAT1 signaling network.

Methods

We obtained the multi-dimensional genomic data from publicly available databases and correlated them with the four gene expression-based subtypes we recently identified in endometrial cancer. Upstream regulator analysis was used to identify the most significantly enriched transcription regulators and Ingenuity pathway analysis was applied to determine enrichment of signaling pathways in survival-associated genes. Gene set enrichment analysis was performed on the 200-gene T-cell tumor infiltration gene signature comparing Cluster IV with the other three clusters combined. All statistical tests were two-sided, and a P value of less than 0.05 is considered significant across all analyses performed.

Conclusion

This study helps to identify patients with immune activation who are likely to benefit from emerging immune checkpoint inhibitors.

Role of Tumor-Associated Macrophages in the Clinical Course of Pancreatic Neuroendocrine Tumors (PanNETs)

PURPOSE

This study evaluated the potential role of immune cells and molecules in the pathogenesis and clinical course of pancreatic neuroendocrine tumors (PanNET).

EXPERIMENTAL DESIGN

Surgically resected PanNETs (N = 104) were immunohistochemically analyzed for Ki67 index, mitotic rate, macrophage, CD4⁺ cells, and CD8⁺ T-cell infiltration, as well as HLA class I, PD-L1, and B7-H3 expression. Results were correlated with clinicopathologic characteristics as well as with disease-free (DFS) and disease-specific (DSS) survival.

RESULTS

The median age of the 57 WHO grade 1 and 47 WHO grade 2 patients was 55 years. High intratumoral CD8⁺ T-cell infiltration correlated with prolonged DFS (P = 0.05), especially when the number of tumor-associated macrophages (TAM) was low. In contrast, high peritumoral CD4⁺ cell and TAM infiltration was associated with a worse DFS and DSS. PD-L1 and B7-H3 were expressed in 53% and 78% PanNETs, respectively. HLA class I expression was defective in about 70% PanNETs. HLA-A expression correlated with favorable DSS in PD-L1-negative tumors (P = 0.02). TAM infiltration (P = 0.02), WHO grade (P = 0.04), T stage (P = 0.01), and lymph node positivity (P = 0.04) were independent predictors of DFS. TAM infiltration (P = 0.026) and T stage (P = 0.012) continued to be predictors of DFS in WHO grade 1 PanNET patients. TAM infiltration was the sole independent predictor of DSS for WHO grade 1 and 2 patients (P = 0.02). Therefore, this biomarker may contribute to identifying WHO grade 1 patients with poor prognosis.

CONCLUSIONS

TAM infiltration appears to be the most informative prognostic biomarker in PanNET. It may represent a useful immunotherapeutic target in patients with PanNET.

Local immune parameters as potential predictive markers in head and neck squamous cell carcinoma patients receiving induction chemotherapy and cetuximab

BACKGROUND

The aim of this study was to determine whether tumor-associated immune cells may predict response to therapy and disease outcome in head and neck squamous cell carcinoma (HNSCC) patients receiving induction chemotherapy and cetuximab.

METHODS

Paraffin-embedded pretreatment biopsy samples from 45 patients with stage III-IV resectable HNSCC were investigated retrospectively by immunohistochemistry for density of different immune cell types based on expression of CD8, FOXP3, CD134, CD137, PD-1, CD20, NKp46, dendritic cell lysosomal-associated membrane protein (DC-LAMP), CD16, CD68, and myeloperoxidase. Results were analyzed for possible correlations with clinicopathologic parameters, response to therapy, and survival.

RESULTS

Of the immune cell types studied, we found significant association with response to induction chemotherapy only in the case of DC-LAMP⁺ mature dendritic cells and PD-1⁺ lymphocytes; density of DC-LAMP⁺ cells also correlated with progression-free survival.

CONCLUSION

DC-LAMP⁺ mature dendritic cells and PD-1⁺ cells may be implicated in response to induction chemotherapy and cetuximab in HNSCC patients.

A High-Throughput Immune-Oncology Screen Identifies EGFR Inhibitors as Potent Enhancers of Antigen-Specific Cytotoxic T-lymphocyte Tumor Cell Killing

We developed a screening assay in which luciferized ID8 expressing OVA was cocultured with transgenic CD8+ T cells specifically recognizing the model antigen in an H-2b-restricted manner. The assay was screened with a small-molecule library to identify compounds that inhibit or enhance T cell-mediated killing of tumor cells. Erlotinib, an EGFR inhibitor, was the top compound that enhanced T-cell killing of tumor cells. Subsequent experiments with erlotinib and additional EGFR inhibitors validated the screen results. EGFR inhibitors increased both basal and IFNγ-induced MHC class-I presentation, which enhanced recognition and lysis of tumor cell targets by CD8+ cytotoxic T lymphocytes. The ID8 cell line was also transduced to constitutively express Cas9, and a pooled CRISPR screen, utilizing the same target tumor cell/T-cell assay, identified single-guide (sg)RNAs targeting EGFR that sensitized tumor cells to T cell-mediated killing. Combination of PD-1 blockade with EGFR inhibition showed significant synergistic efficacy in a syngeneic model, further validating EGFR inhibitors as immunomodulatory agents that enhance checkpoint blockade. This assay can be screened in high-throughput with small-molecule libraries and genome-wide CRISPR/Cas9 libraries to identify both compounds and target genes, respectively, that enhance or inhibit T-cell recognition and killing of tumor cells. Retrospective analyses of squamous-cell head and neck cancer (SCCHN) patients treated with the combination of afatinib and pembrolizumab demonstrated a rate of clinical activity exceeding that of each single agent. Prospective clinical trials evaluating the combination of an EGFR inhibitor and PD-1 blockade should be conducted.

Tailoring cells for clinical needs: Meeting report from the Advanced Therapy in Healthcare symposium (October 28-29 2017, Doha, Qatar)

New technologies and therapies designed to facilitate development of personalized treatments are rapidly emerging in the field of biomedicine. Strikingly, the goal of personalized medicine refined the concept of therapy by developing cell-based therapies, the so-called “living drugs”. Breakthrough advancements were achieved in this regard in the fields of gene therapy, cell therapy, tissue-engineered products and advanced therapeutic techniques. The Advanced Therapies in Healthcare symposium, organized by the Clinical Research Center Department of Sidra Medicine, in Doha, Qatar (October 2017), brought together world-renowned experts from the fields of oncology, hematology, immunology, inflammation, autoimmune disorders, and stem cells to offer a comprehensive picture of the status of worldwide advanced therapies in both pre-clinical and clinical development, providing insights to the research phase, clinical data and regulatory aspects of these therapies. Highlights of the meeting are provided in this meeting report.

EGFR signaling suppresses type 1 cytokine-induced T-cell attracting chemokine secretion in head and neck cancer

Resistance to antitumor immunity can be promoted by the oncogenic pathways operational in human cancers, including the epidermal growth factor receptor (EGFR) pathway. Here we studied if and how EGFR downstream signaling in head and neck squamous cell carcinoma (HNSCC) can affect the attraction of immune cells. HPV-negative and HPV-positive HNSCC cell lines were analyzed in vitro for CCL2, CCL5, CXCL9, CXCL10, IL-6 and IL-1β expression and the attraction of T cells under different conditions, including cetuximab treatment and stimulation with IFNγ and TNFα using qPCR, ELISA and migration experiments. Biochemical analyses with chemical inhibitors and siRNA transfection were used to pinpoint the underlying mechanisms. Stimulation of HNSCC cells with IFNγ and TNFα triggered the production of T-cell attracting chemokines and required c-RAF activation. Blocking of the EGFR with cetuximab during this stimulation increased chemokine production in vitro, and augmented the attraction of T cells. Mechanistically, cetuximab decreased the phosphorylation of MEK1, ERK1/2, AKT, mTOR, JNK, p38 and ERK5. Chemical inhibition of EGFR signaling showed a consistent and pronounced chemokine production with MEK1/2 inhibitor PD98059 and JNK inhibitor SP600125, but not with inhibitors of p38, PI3K or mTOR. Combination treatment with cetuximab and a MEK1/2 or JNK inhibitor induced the highest chemokine expression. In conclusion, overexpression of EGFR results in the activation of multiple downstream signaling pathways that act simultaneously to suppress type 1 cytokine stimulated production of chemokines required to amplify the attraction of T cells.

Influence of tumor-associated macrophages and HLA class I expression according to HPV status in head and neck cancer patients receiving chemo/bioradiotherapy

BACKGROUND AND PURPOSE

To investigate the prognostic value of tumor-associated macrophages (TAM) and HLA class I expression according to HPV status in patients with head and neck squamous cell carcinoma treated with definitive radiotherapy combining cisplatin (CRT) or cetuximab (BRT).

MATERIAL AND METHODS

Ninety-five patients were enrolled. The density of CD68+ cells and CD68+ CD163+ cells (further referred as M2) in the intraepithelial and the stromal compartments, respectively, as well as HLA class I expression in tumor cells, were evaluated semi-quantitatively. Correlations between biomarker expression and treatment outcomes were analyzed.

RESULTS

Multivariate analysis showed that the intraepithelial macrophage density (IEMD) was prognostic for favorable progression-free survival (PFS) and there was a non-significant trend for improved overall survival (OS). HLA class I down-regulation was not an independent prognostic factor. Subgroup analysis showed that in p16+ population, patients with high IEMD had improved 5-year PFS vs. patients with low IEMD (81.2% vs. 25.0%, p < 0.001), while in p16- population, no difference was observed. Similarly, when stratified by primary tumor site, IEMD showed prognostic value in oropharyngeal cancer patients (OPC) but not non-OPC patients. Five-year PFS of patients with low stromal M2 macrophage density treated with CRT was significantly improved vs. those with BRT (54.5% vs. 36.1%, p = 0.03), while in tumors with high M2, there was no significant difference (50.3% vs. 42.9%, p = 0.67).

CONCLUSIONS

The prognostic role of TAM phenotype and distribution depends on HPV status and might predict treatment response. They prompt further validation in prospective studies.

Elimination of melanoma by sortase A-generated TCR-like antibody-drug conjugates (TL-ADCs) targeting intracellular melanoma antigen MART-1

Most tumor-associated proteins are located inside tumor cells and thus are not accessible to current marketed therapeutic monoclonal antibodies or their cytotoxic conjugates. Human leukocyte antigen (HLA) class I can present peptides derived from intracellular tumor-associated proteins and somatically mutated proteins on the cell's surface, forming an HLA/peptide complex as tumor-specific antigens for T cell receptor (TCR) recognition. Therefore, HLA-mediated presentation of intracellular tumor antigen peptides provides a viable way to distinguish tumor cells from normal cells, which is important for broadening antigen selection, especially for antibody-drug conjugates (ADCs) regarding their highly cytotoxic payload. We applied sortase A-mediated conjugation to develop TCR-like ADCs (i.e., EA1 HL-vcMMAE) targeting intracellular MART-1 protein, a melanocyte-differentiating antigen specific for metastatic melanomas, via the cell surface HLA-A2/MART-1_26-35 peptide complex. Homogenous EA1 HL-vcMMAE (drug to antibody ratio of 4) efficiently eliminated melanoma cells in xenograft mouse models with no obvious toxicity at the therapeutic dosage. Trametinib, an MEK inhibitor serving as an HLA expression enhancing agent, augmented the TL-ADCs' efficacy both in vitro and in vivo by upregulating MART-1_26-35 peptide presentation, thus providing a strategy for overcoming the limitation of antigen presentation level for TL-ADCs. Hence, our findings validate the strategy of using sortase A-generated TL-ADCs to target tumor-specific intracellular proteins, with or without agents present, to increase presenting TCR epitope peptides.

Defective HLA class I antigen processing machinery in cancer

Malignant transformation of cells is frequently associated with defective HLA class I antigen processing machinery (APM) component expression. This abnormality may have functional relevance, since it may have a negative impact on tumor cell recognition by cognate T cells. Furthermore, HLA class I APM abnormalities appear to have clinical significance, since they are associated with poor prognosis in several malignant diseases and may play a role in the resistance to immune checkpoint inhibitor-based immunotherapy. In this paper, we have reviewed the literature describing abnormalities in HLA class I APM component expression in many types of cancer. These abnormalities have been reported in all types of cancer analyzed with a frequency ranging between a minimum of 35.8% in renal cancer and a maximum of 87.9% in thyroid cancer for HLA class I heavy chains. In addition, we have described the molecular mechanisms underlying defects in HLA class I APM component expression and function by malignant cells. Lastly, we have discussed the clinical significance of HLA class I APM component abnormalities in malignant tumors.

Cancer/testis Antigen MAGEA3 Interacts with STAT1 and Remodels the Tumor Microenvironment

Cancer-testis antigen MAGEA3, being restrictedly expressed in testis and various kinds of tumors, has long been considered as an ideal target for immunotherapy. In this study, we report that MAGEA3 interacts with STAT1 and regulates the expression of tyrosine phosphorylated STAT1 (pY-STAT1) in tumor cells. We show that pY-STAT1 is significantly up-regulated when MAGEA3 is silenced by MAGEA3-specific siRNA. RNA sequencing analysis identified 274 STAT1-related genes to be significantly altered in expression level in MAGEA3 knockdown cells. Further analysis of these differentially expressed genes with GO enrichment and KEGG pathway revealed that they are mainly enriched in plasma membrane, extracellular region and MHC class I protein complex, and involved in the interferon signaling pathways, immune response, antigen presentation and cell chemotaxis. The differentially expressed genes associated with chemokines, antigen presentation and vasculogenic mimicry formation were validated by biological experiments. Matrigel matrix-based tube formation assay showed that silencing MAGEA3 in tumor cells impairs tumor vasculogenic mimicry formation. These data indicate that MAGEA3 expression in tumor cells is associated with immune cells infiltration into tumor microenvironment and anti-tumor immune responses, implying that it may play an important role in tumor immune escape. Our findings reveal the potential impact of MAGEA3 on the immunosuppressive tumor microenvironment and will provide promising strategies for improving the efficacy of MAGEA3-targeted immunotherapy.

Targeted Therapies: Immunologic Effects and Potential Applications Outside of Cancer

Two pharmacologic approaches that are currently at the forefront of treating advanced cancer are those that center on disrupting critical growth/survival signaling pathways within tumor cells (commonly referred to as "targeted therapies") and those that center on enhancing the capacity of a patient's immune system to mount an antitumor response (immunotherapy). Maximizing responses to both of these approaches requires an understanding of the oncogenic events present in a given patient's tumor and the nature of the tumor-immune microenvironment. Although these 2 modalities were developed and initially used independently, combination regimens are now being tested in clinical trials, underscoring the need to understand how targeted therapies influence immunologic events. Translational studies and preclinical models have demonstrated that targeted therapies can influence immune cell trafficking, the production of and response to chemokines and cytokines, antigen presentation, and other processes relevant to antitumor immunity and immune homeostasis. Moreover, because these and other effects of targeted therapies occur in nonmalignant cells, targeted therapies are being evaluated for use in applications outside of oncology.

Rationale for combination of therapeutic antibodies targeting tumor cells and immune checkpoint receptors: Harnessing innate and adaptive immunity through IgG1 isotype immune effector stimulation

Immunoglobulin (Ig) G1 antibodies stimulate antibody-dependent cell-mediated cytotoxicity (ADCC). Cetuximab, an IgG1 isotype monoclonal antibody, is a standard-of-care treatment for locally advanced and recurrent and/or metastatic squamous cell carcinoma of the head and neck (SCCHN) and metastatic colorectal cancer (CRC). Here we review evidence regarding the clinical relevance of cetuximab-mediated ADCC and other immune functions and provide a biological rationale concerning why this property positions cetuximab as an ideal partner for immune checkpoint inhibitors (ICIs) and other emerging immunotherapies. We performed a nonsystematic review of available preclinical and clinical data involving cetuximab-mediated immune activity and combination approaches of cetuximab with other immunotherapies, including ICIs, in SCCHN and CRC. Indeed, cetuximab mediates ADCC activity in the intratumoral space and primes adaptive and innate cellular immunity. However, counterregulatory mechanisms may lead to immunosuppressive feedback loops. Accordingly, there is a strong rationale for combining ICIs with cetuximab for the treatment of advanced tumors, as targeting CTLA-4, PD-1, and PD-L1 can ostensibly overcome these immunosuppressive counter-mechanisms in the tumor microenvironment. Moreover, combining ICIs (or other immunotherapies) with cetuximab is a promising strategy for boosting immune response and enhancing response rates and durability of response. Cetuximab immune activity–including, but not limited to, ADCC–provides a strong rationale for its combination with ICIs or other immunotherapies to synergistically and fully mobilize the adaptive and innate immunity against tumor cells. Ongoing prospective studies will evaluate the clinical effect of these combination regimens and their immune effect in CRC and SCCHN and in other indications.

Cisplatin Alters Antitumor Immunity and Synergizes with PD-1/PD-L1 Inhibition in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) has been treated for decades with cisplatin chemotherapy, and anti-PD-1 immunotherapy has recently been approved for the treatment of this disease. However, preclinical studies of how antitumor immunity in HNSCC is affected by cisplatin alone or in combination with immunotherapies are lacking. Here, we show that sublethal doses of cisplatin may enhance antigen presentation and T-cell killing in vitro, though cisplatin also upregulates tumor cell expression of PD-L1 and may impair T-cell function at higher doses. In a syngeneic mouse model of HNSCC, concurrent use of cisplatin and anti-PD-L1/PD-1 delayed tumor growth and enhanced survival without significantly reducing the number or function of tumor-infiltrating immune cells or increasing cisplatin-induced toxicities. These results suggest that moderate doses of cisplatin may enhance antitumor immunity by mechanisms other than direct tumor cell killing, which may be further enhanced by anti-PD-L1/PD-1 therapy. Cancer Immunol Res; 5(12); 1141-51. ©2017 AACR.

Future cancer research priorities in the USA: a Lancet Oncology Commission

We are in the midst of a technological revolution that is providing new insights into human biology and cancer. In this era of big data, we are amassing large amounts of information that is transforming how we approach cancer treatment and prevention. Enactment of the Cancer Moonshot within the 21st Century Cures Act in the USA arrived at a propitious moment in the advancement of knowledge, providing nearly US$2 billion of funding for cancer research and precision medicine. In 2016, the Blue Ribbon Panel (BRP) set out a roadmap of recommendations designed to exploit new advances in cancer diagnosis, prevention, and treatment. Those recommendations provided a high-level view of how to accelerate the conversion of new scientific discoveries into effective treatments and prevention for cancer. The US National Cancer Institute is already implementing some of those recommendations. As experts in the priority areas identified by the BRP, we bolster those recommendations to implement this important scientific roadmap. In this Commission, we examine the BRP recommendations in greater detail and expand the discussion to include additional priority areas, including surgical oncology, radiation oncology, imaging, health systems and health disparities, regulation and financing, population science, and oncopolicy. We prioritise areas of research in the USA that we believe would accelerate efforts to benefit patients with cancer. Finally, we hope the recommendations in this report will facilitate new international collaborations to further enhance global efforts in cancer control.

Upregulation of HLA Class I Expression on Tumor Cells by the Anti-EGFR Antibody Nimotuzumab

Defining how epidermal growth factor receptor (EGFR)-targeting therapies influence the immune response is essential to increase their clinical efficacy. A growing emphasis is being placed on immune regulator genes that govern tumor – T cell interactions. Previous studies showed an increase in HLA class I cell surface expression in tumor cell lines treated with anti-EGFR agents. In particular, earlier studies of the anti-EGFR blocking antibody cetuximab, have suggested that increased tumor expression of HLA class I is associated with positive clinical response. We investigated the effect of another commercially available anti-EGFR antibody nimotuzumab on HLA class I expression in tumor cell lines. We observed, for the first time, that nimotuzumab increases HLA class I expression and its effect is associated with a coordinated increase in mRNA levels of the principal antigen processing and presentation components. Moreover, using 7A7 (a specific surrogate antibody against murine EGFR), we obtained results suggesting the importance of the increased MHC-I expression induced by EGFR-targeted therapies display higher in antitumor immune response. 7A7 therapy induced upregulation of tumor MHC-I expression in vivo and tumors treated with this antibody display higher susceptibility to CD8⁺ T cells-mediated lysis. Our results represent the first evidence suggesting the importance of the adaptive immunity in nimotuzumab-mediated antitumor activity. More experiments should be conducted in order to elucidate the relevance of this mechanism in cancer patients. This novel immune-related antitumor mechanism mediated by nimotuzumab opens new perspectives for its combination with various immunotherapeutic agents and cancer vaccines.