CD45RA-Foxp3high regulatory T cells have a negative impact on the clinical outcome of head and neck squamous cell carcinoma

Specific knockout of Notch2 in Treg cells significantly inhibits the growth and proliferation of head and neck squamous cell carcinoma in mice

OBJECTIVE

To investigate the effect of Notch2 gene knockout in Treg cells on head and neck squamous cell carcinoma (HNSCC) in mice.

METHODS

A mouse model of HNSCC was constructed. Flow cytometry and immunofluorescence were used to examine the numbers of related immune cells and programmed cell death in tumor cells in the spleen and tumor microenvironment of mice. Western blotting was used to measure the expression of related proteins in tumor tissues.

RESULTS

The tumor volume of regulatory T (Treg) cell-specific Notch2-knockout mice (experimental group) was significantly smaller than that of control mice (control group) (P < 0.05). Compared with those in the control group, the number of Treg cells and the expression of Ki67 in Treg cells in the spleen and tumor tissue were significantly decreased in the experimental group, while the numbers of CD45+ hematopoietic cells, CD4+ T cells, CD8+ T cells, T helper 1 (Th1) cells, CD11b+ cells (macrophages), and CD11b+CD11c+ cells (dendritic cells) and the expression of Ki67 in CD4+ T cells and CD8+ T cells were significantly increased (P < 0.05). There was no significant difference in the number of Th2 cells between the two groups (P > 0.05). Immunofluorescence analysis showed that the numbers of CD4+ T cells and CD8+ T cells in the tumor tissue in the experimental group were significantly higher than those in the control group (P < 0.05). Compared with that in the control group, programmed cell death in the experimental group was significantly increased (P < 0.05). Moreover, the expression levels of NLRP3, Caspase-1 and GSDMD in the tumor tissues of the experimental group were higher than those in the control group (P < 0.01), while the expression levels of BCL2, Bax, ATG5, LC3 and p62 were not significantly different (P > 0.05).

CONCLUSIONS

Specific knockout of the Notch2 gene in Treg cells significantly decreases the function of Treg cells, inhibits the growth of HNSCC and improves the immune microenvironment in mice, thus effectively treating HNSCC.

Selective targeting of IL2Rβγ combined with radiotherapy triggers CD8- and NK-mediated immunity, abrogating metastasis in HNSCC

The implementation of cancer immunotherapies has seen limited clinical success in head and neck squamous cell carcinoma (HNSCC). Interleukin-2 (IL-2), which modulates the survival and functionality of lymphocytes, is an attractive target for new immunotherapies but one that is limited by presence of regulatory T cells (Tregs) expressing the high-affinity IL-2Rα. The bispecific immunocytokine PD1-IL2v preferentially delivers IL-2 signaling through IL-2Rβγ on PD-1-expressing cells. Selectively targeting the intermediate-affinity IL-2Rβγ can be leveraged to induce anti-tumor immune responses in effector T cells and natural killer (NK) cells while limiting the negative regulation of IL-2Rα activation on Tregs. Using radiation therapy (RT) in combination with PD1-IL2v improves local tumor control and survival, and controls metastatic spread in orthotopic HNSCC tumor models. PD1-IL2v drives systemic activation and expansion of circulating and tumor-infiltrating cytotoxic T cells and NK cells while limiting Treg-mediated immunosuppression. These data show that PD1-L2v induces durable systemic tumor control in HNSCC.

The Role of Different Immunocompetent Cell Populations in the Pathogenesis of Head and Neck Cancer-Regulatory Mechanisms of Pro- and Anti-Cancer Activity and Their Impact on Immunotherapy

Head and neck squamous cell carcinoma (HNSCC) is one of the most aggressive and heterogeneous groups of human neoplasms. HNSCC is characterized by high morbidity, accounting for 3% of all cancers, and high mortality with ~1.5% of all cancer deaths. It was the most common cancer worldwide in 2020, according to the latest GLOBOCAN data, representing the seventh most prevalent human malignancy. Despite great advances in surgical techniques and the application of modern combinations and cytotoxic therapies, HNSCC remains a leading cause of death worldwide with a low overall survival rate not exceeding 40-60% of the patient population. The most common causes of death in patients are its frequent nodal metastases and local neoplastic recurrences, as well as the relatively low response to treatment and severe drug resistance. Much evidence suggests that the tumour microenvironment (TME), tumour infiltrating lymphocytes (TILs) and circulating various subpopulations of immunocompetent cells, such regulatory T cells (CD4+CD25+Foxp3+Tregs), cytotoxic CD3+CD8+ T cells (CTLs) and CD3+CD4+ T helper type 1/2/9/17 (Th1/Th2/Th9/Th17) lymphocytes, T follicular helper cells (Tfh) and CD56dim/CD16bright activated natural killer cells (NK), carcinoma-associated fibroblasts (CAFs), myeloid-derived suppressor cells (MDSCs), tumour-associated neutrophils (N1/N2 TANs), as well as tumour-associated macrophages (M1/M2 phenotype TAMs) can affect initiation, progression and spread of HNSCC and determine the response to immunotherapy. Rapid advances in the field of immuno-oncology and the constantly growing knowledge of the immunosuppressive mechanisms and effects of tumour cancer have allowed for the use of effective and personalized immunotherapy as a first-line therapeutic procedure or an essential component of a combination therapy for primary, relapsed and metastatic HNSCC. This review presents the latest reports and molecular studies regarding the anti-tumour role of selected subpopulations of immunocompetent cells in the pathogenesis of HNSCC, including HPV+ve (HPV+) and HPV-ve (HPV-) tumours. The article focuses on the crucial regulatory mechanisms of pro- and anti-tumour activity, key genetic or epigenetic changes that favour tumour immune escape, and the strategies that the tumour employs to avoid recognition by immunocompetent cells, as well as resistance mechanisms to T and NK cell-based immunotherapy in HNSCC. The present review also provides an overview of the pre- and clinical early trials (I/II phase) and phase-III clinical trials published in this arena, which highlight the unprecedented effectiveness and limitations of immunotherapy in HNSCC, and the emerging issues facing the field of HNSCC immuno-oncology.

Trametinib improves Treg selectivity of anti-CCR4 antibody by regulating CCR4 expression in CTLs in oral squamous cell carcinoma

Regulatory T-cells (Tregs) play a major role in suppressing anti-tumor immune responses. Mogamulizumab, an anti-CC chemokine receptor type 4 (CCR4) monoclonal antibody, depletes effector Tregs (eTregs). However, the clinical efficacy of mogamulizumab was limited in phase Ia/Ib studies for solid tumors (NCT01929486); the finding suggests that mogamulizumab may also deplete beneficial CCR4⁺CD8⁺ T-cells in patients. Therefore, we focused on CTLs and aimed to identify a way to protect CCR4⁺ CTLs. Here, we evaluated the association of CCR4 expression in cytotoxic T-lymphocytes (CTLs) with antigen and cytokine stimulations and kinase inhibition using cytomegalovirus antigen instead of tumor antigen. CCR4 expression in CTLs was induced by antigen stimulation (mean 3.14-29.0%), enhanced by transforming growth factor-β1 (TGF-β1) (mean 29.0-51.2%), and downregulated by trametinib with (mean 51.2-11.4%) or without TGF-β1 treatment (mean 29.0-6.98%). Phosphorylation of ERK in CD8⁺ T-cells was suppressed by trametinib. Regarding the effect on immunological function of CTL, trametinib reduced cytokine production but not affected cytotoxicity. Importantly, trametinib alleviated CTL reduction by anti-CCR4 antibody without affecting eTreg depletion because CCR4 expression in eTregs was not downregulated. In conclusion, combination therapy with trametinib may improve the clinical efficacy of mogamulizumab.

The Prognostic and Predictive Significance of Tumor-Infiltrating Memory T Cells Is Reversed in High-Risk HNSCC

Tumor-infiltrating CD45RO+ memory T cells have unanimously been described as a positive prognostic factor in head and neck squamous cell carcinomas (HNSCCs). Here, we investigated the long-term prognostic relevance of CD45RO+ memory T cells in HNSCC with special regard to the influence of clinical characteristics. Pre-treatment biopsy samples from 306 patients with predominantly advanced HNSCC were analyzed. Immunohistochemistry was used to stain tissue microarrays for CD45RO+ memory T cells. CD45RO cell densities were semi-automatically registered and used for survival analysis. High CD45RO+ cell densities were clearly associated with prolonged overall survival (OS) and recurrence-free survival as well as no evidence of disease status after 10 years (p < 0.05). In contrast, the prognostic significance of tumor-infiltrating memory T cells was completely reversed in high-risk groups: in poorly differentiated tumors (G3, G4) and in cases with lymph node involvement (N+), high memory T cell densities correlated with reduced 10-year OS (p < 0.05). In conclusion, an increased density of tumor-infiltrating CD45RO+ cells in HNSCC can be a positive as well as a negative prognostic factor, depending on disease stage and histological grade. Therefore, if CD45RO+ cell density is to be used as a prognostic biomarker, further clinical characteristics must be considered.

Targeting regulatory T cells in anti-PD-1/PD-L1 cancer immunotherapy

The programmed death (PD)-1/PD-ligand (PD-L) pathway and regulatory T cells (Tregs) are essential for the maintenance of immune tolerance. Their activation in the tumor microenvironment contributes to the evasion of the transformed cells from the immune surveillance and the suppression of an antitumor immune response. Therefore, PD-1/PD-L1 and Tregs are important targets for cancer immunotherapy. Our review focuses on the current role of the PD-1/PD-L1 axis in Treg development and function in the tumor microenvironment. We also discuss combination therapy with PD-1/PD-L1 inhibitors and Treg-modulating agents affecting the adenosinergic pathway, TGF-β signaling, immune checkpoints, and other approaches to downregulation of Tregs.

Outcome and Immune Correlates of a Phase II Trial of High-Dose Interleukin-2 and Stereotactic Ablative Radiotherapy for Metastatic Renal Cell Carcinoma

PURPOSE

This phase II clinical trial evaluated whether the addition of stereotactic ablative radiotherapy (SAbR), which may promote tumor antigen presentation, improves the overall response rate (ORR) to high-dose IL2 (HD IL2) in metastatic renal cell carcinoma (mRCC).

PATIENTS AND METHODS

Patients with pathologic evidence of clear cell renal cell carcinoma (RCC) and radiographic evidence of metastasis were enrolled in this single-arm trial and were treated with SAbR, followed by HD IL2. ORR was assessed based on nonirradiated metastases. Secondary endpoints included overall survival (OS), progression-free survival (PFS), toxicity, and treatment-related tumor-specific immune response. Correlative studies involved whole-exome and transcriptome sequencing, T-cell receptor sequencing, cytokine analysis, and mass cytometry on patient samples.

RESULTS

Thirty ethnically diverse mRCC patients were enrolled. A median of two metastases were treated with SAbR. Among 25 patients evaluable by RECIST v1.1, ORR was 16% with 8% complete responses. Median OS was 37 months. Treatment-related adverse events (AE) included 22 grade ≥3 events that were not dissimilar from HD IL2 alone. There were no grade 5 AEs. A correlation was observed between SAbR to lung metastases and improved PFS (P = 0.0165). Clinical benefit correlated with frameshift mutational load, mast cell tumor infiltration, decreased circulating tumor-associated T-cell clones, and T-cell clonal expansion. Higher regulatory/CD8+ T-cell ratios at baseline in the tumor and periphery correlated with no clinical benefit.

CONCLUSIONS

Adding SAbR did not improve the response rate to HD IL2 in patients with mRCC in this study. Tissue analyses suggest a possible correlation between frameshift mutation load as well as tumor immune infiltrates and clinical outcomes.

Prevalence of intratumoral regulatory T cells expressing neuropilin-1 is associated with poorer outcomes in patients with cancer

[Figure: see text].

Tumors establish resistance to immunotherapy by regulating Treg recruitment via CCR4

BACKGROUND

Checkpoint inhibitors (CPIs) such as anti-PD(L)-1 and anti-CTLA-4 antibodies have resulted in unprecedented rates of antitumor responses and extension of survival of patients with a variety of cancers. But some patients fail to respond or initially respond but later relapse as they develop resistance to immune therapy. One of the tumor-extrinsic mechanisms for resistance to immune therapy is the accumulation of regulatory T cells (T_reg) in tumors. In preclinical and clinical studies, it has been suggested that tumor trafficking of T_reg is mediated by CC chemokine receptor 4 (CCR4). Over 90% of human T_reg express CCR4 and migrate toward CCL17 and CCL22, two major CCR4 ligands that are either high at baseline or upregulated in tumors on CPI treatment. Hence, CCR4 antagonism has the potential to be an effective antitumor treatment by reducing the accumulation of T_reg into the tumor microenvironment (TME).

METHODS

We developed in vitro and in vivo models to assess T_reg migration and antitumor efficacy using a potent and selective CCR4 antagonist, CCR4-351. We used two separate tumor models, Pan02 and CT26 mouse tumors, that have high and low CCR4 ligand expression, respectively. Tumor growth inhibition as well as the frequency of tumor-infiltrating T_reg and effector T cells was assessed following the treatment with CCR4 antagonist alone or in combination with CPI.

RESULTS

Using a selective and highly potent, novel small molecule inhibitor of CCR4, we demonstrate that migration of CCR4⁺ T_reg into the tumor drives tumor progression and resistance to CPI treatment. In tumor models with high baseline levels of CCR4 ligands, blockade of CCR4 reduced the number of T_reg and enhanced antitumor immune activity. Notably, in tumor models with low baseline level of CCR4 ligands, treatment with immune CPIs resulted in significant increases of CCR4 ligands and T_reg numbers. Inhibition of CCR4 reduced T_reg frequency and potentiated the antitumor effects of CPIs.

CONCLUSION

Taken together, we demonstrate that CCR4-dependent T_reg recruitment into the tumor is an important tumor-extrinsic mechanism for immune resistance. Blockade of CCR4 led to reduced frequency of T_reg and resulted in increased antitumor activity, supporting the clinical development of CCR4 inhibitors in combination with CPI for the treatment of cancer.

STATEMENT OF SIGNIFICANCE

CPI upregulates CCL17 and CCL22 expression in tumors and increases T_reg migration into the TME. Pharmacological antagonism of the CCR4 receptor effectively inhibits T_reg recruitment and results in enhanced antitumor efficacy either as single agent in CCR4 ligand^high tumors or in combination with CPIs in CCR4 ligand^low tumors.

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.

Treg: A Promising Immunotherapeutic Target in Oral Diseases

With the pandemic of COVID-19, maintenance of oral health has increasingly become the main challenge of global health. Various common oral diseases, such as periodontitis and oral cancer, are closely associated with immune disorders in the oral mucosa. Regulatory T cells (Treg) are essential for maintaining self-tolerance and immunosuppression. During the process of periodontitis and apical periodontitis, two typical chronic immune-inflammatory diseases, Treg contributes to maintain host immune homeostasis and minimize tissue damage. In contrast, in the development of oral precancerous lesions and oral cancer, Treg is expected to be depleted or down-regulated to enhance the anti-tumor immune response. Therefore, a deeper understanding of the distribution, function, and regulatory mechanisms of Treg cells may provide a prospect for the immunotherapy of oral diseases. In this review, we summarize the distribution and multiple roles of Treg in different oral diseases and discuss the possible mechanisms involved in Treg cell regulation, hope to provide a reference for future Treg-targeted immunotherapy in the treatment of oral diseases.

The characteristics of the immune cell profiles in peripheral blood in cholangiocarcinoma patients

BACKGROUND

Immune related cells are known to be closely related to the therapeutic effects and prognoses of cancer patients. In this study, we analyzed immune cell profiles (ICP) of cholangiocarcinoma patients (CCA).

METHODS

To measure the frequency of immune cells, peripheral blood mononuclear cells of 41 CCA and 10 healthy volunteers (HV) were analyzed by FACS.

RESULTS

There were significant differences between CCA and HV in ICP, and these differences were a consequence of tumor-bearing status, because many items in ICP before surgery were restored to levels in HV after surgery. Therefore, these changes were specifically attributable to cholangiocarcinoma, and we examined if they can function as biomarkers for therapeutic effects and prognoses. A shorter overall survival was associated with a lower frequency of helper T cells (HT) (p = 0.001), a higher frequency of effector regulatory T cells (eTregs) (p = 0.008), and a lower frequency of CD80 + eTregs (p = 0.024) in the best supportive care group, with a lower frequency of CD25 + naïve Tregs (nTregs) (p = 0.005) in the chemotherapy group, and with a lower frequency of OX40 + HT (p = 0.022), CD25 + CD8 + T cells (p = 0.017), and OX40 + CD8 + T cells (p = 0.032) in the surgery group. The recurrence factors were a higher frequency of CD4 + T cells (p = 0.009), CCR6 + nTregs (p = 0.014), and CXCR3 + nTregs (p = 0.012), and a lower frequency of PD-1 + HT (p = 0.006), OX40 + HT (p = 0.004), CD8 + T cells (p = 0.001), and CTLA-4 + CD8 + T cells (p = 0.036).

CONCLUSIONS

The ICP in CCA are specifically attributable to cholangiocarcinoma, and may be biomarkers for therapeutic effects and prognoses.

Novel Piperidinyl-Azetidines as Potent and Selective CCR4 Antagonists Elicit Antitumor Response as a Single Agent and in Combination with Checkpoint Inhibitors

The C-C chemokine receptor 4 (CCR4) is broadly expressed on regulatory T cells (T_reg) as well as other circulating and tissue-resident T cells. T_reg can be recruited to the tumor microenvironment (TME) through the C-C chemokines CCL17 and CCL22. T_reg accumulation in the TME has been shown to dampen the antitumor immune response and is thought to be an important driver in tumor immune evasion. Preclinical and clinical data suggest that reducing the T_reg population in the TME can potentiate the antitumor immune response of checkpoint inhibitors. We have developed small-molecule antagonists of CCR4, featuring a novel piperidinyl-azetidine motif, that inhibit the recruitment of T_reg into the TME and elicit antitumor responses as a single agent or in combination with an immune checkpoint blockade. The discovery of these potent, selective, and orally bioavailable CCR4 antagonists, and their activity in in vitro and in vivo models, is described herein.

Foxp3+ Regulatory T Cells Associated With CCL17/CCR4 Expression in Carcinomas of Dogs

Regulatory T cells (Tregs) can be targeted in cancer immunotherapy. A previous study has shown that the chemokine CCL17 and the receptor CCR4 play a role in Treg recruitment in canine urothelial carcinoma. Here, we describe the association of tumor-infiltrating Tregs with CCL17/CCR4 expression in dogs with other carcinomas. In this study, we investigated 23 dogs with mammary carcinoma, 14 dogs with oral squamous cell carcinoma, 16 dogs with pulmonary adenocarcinoma, and 8 healthy control dogs. Immunohistochemistry showed that Foxp3⁺ Tregs and CCR4⁺ cells were increased in the tumor tissues of mammary carcinoma, squamous cell carcinoma, and pulmonary adenocarcinoma, when compared with the healthy tissues. The number of CCR4⁺ cells was associated with that of Foxp3⁺ Tregs. Double immunofluorescence labeling confirmed that most tumor-infiltrating Foxp3⁺ Tregs expressed CCR4. In vitro, canine carcinoma cell lines expressed CCL17 mRNA. Quantitative RT-PCR (reverse transcriptase-polymerase chain reaction) showed that CCL17 mRNA expression in canine carcinomas was increased approximately 10- to 25-fold relative to that of healthy tissues. These results suggest that the CCL17/CCR4 axis may drive Treg recruitment in a variety of canine carcinomas. CCR4 blockade may be a potential therapeutic option for tumor eradication through Treg depletion.

Dawn of Monitoring Regulatory T Cells in (Pre-)clinical Studies: Their Relevance Is Slowly Recognised

Regulatory T cells (Tregs) have a prominent role in the control of immune homeostasis. Pharmacological impact on their activity or balance with effector T cells could contribute to (impaired) clinical responses or adverse events. Monitoring treatment-related effects on T cell subsets may therefore be part of (pre-)clinical studies for medicinal products. However, the extent of immune monitoring performed in studies for marketing authorisation and the degree of correspondence with data available in the public domain is not known. We evaluated the presence of T cell immunomonitoring in 46 registration dossiers of monoclonal antibodies indicated for immune-related disorders and published scientific papers. We found that the depth of Treg analysis in registration dossiers was rather small. Nevertheless, data on treatment-related Treg effects are available in public academia-driven studies (post-registration) and suggest that Tregs may act as a biomarker for clinical responses. However, public data are fragmented and obtained with heterogeneity of experimental approaches from a diversity of species and tissues. To reveal the potential added value of T cell (and particular Treg) evaluation in (pre-)clinical studies, more cell-specific data should be acquired, at least for medicinal products with an immunomodulatory mechanism. Therefore, extensive analysis of T cell subset contribution to clinical responses and the relevance of treatment-induced changes in their levels is needed. Preferably, industry and academia should work together to obtain these data in a standardised manner and to enrich our knowledge about T cell activity in disease pathogenesis and therapies. This will ultimately elucidate the necessity of T cell subset monitoring in the therapeutic benefit-risk assessment.

Hippo Pathway and YAP Signaling Alterations in Squamous Cancer of the Head and Neck

Head and neck cancer affects the upper aerodigestive tract and is the sixth leading cancer worldwide by incidence and the seventh by cause of death. Despite significant advances in surgery and chemotherapy, molecularly targeted therapeutic options for this type of cancer are scarce and long term survival rates remain low. Recently, comprehensive genomic studies have highlighted the most commonly altered genes and signaling pathways in this cancer. The Hippo-YAP pathway has been identified as a key oncogenic pathway in multiple tumors. Expression of genes controlled by the Hippo downstream transcriptional coactivators YAP (Yes-associated protein 1) and TAZ (WWTR1, WW domain containing transcription regulator 1) is widely deregulated in human cancer including head and neck squamous cell carcinoma (HNSCC). Interestingly, YAP/TAZ signaling might not be as essential for the normal homeostasis of adult tissues as for oncogenic growth, altogether making the pathway an amenable therapeutic target in cancer. Recent advances in the role of Hippo-YAP pathway in HNSCC have provided evidence that genetic alterations frequent in this type of cancer such as PIK3CA (phosphatidylinositide 3-kinase catalytic subunit alpha) overexpression or FAT1 (FAT atypical cadherin 1) functional loss can result in YAP activation. We discuss current therapeutic options targeting this pathway which are currently in use for other tumor types.

Regulatory T cells induce CD4- NKT cell anergy and suppress NKT cell cytotoxic function

BACKGROUND

Due to the strong tumoricidal activities of activated natural killer T (NKT) cells, invariant NKT cell-based immunotherapy has shown promising clinical efficacy. However, suppressive factors, such as regulatory T cells (Tregs), may be obstacles in the use of NKT cell-based cancer immunotherapy for advanced cancer patients. Here, we investigated the suppressive effects of Tregs on NKT cells and the underlying mechanisms with the aim to improve the antitumor activities of NKT cells.

METHODS

Peripheral blood samples were obtained from healthy donors, patients with benign tumors, and patients with head and neck squamous cell carcinoma (HNSCC). NKT cells, induced with α-galactosylceramide (α-GalCer), and monocyte-derived dendritic cells (DCs) were co-cultured with naïve CD4⁺ T cell-derived Tregs to investigate the mechanism of the Treg suppressive effect on NKT cell cytotoxic function. The functions and phenotypes of NKT cells were evaluated with flow cytometry and cytometric bead array.

RESULTS

Treg suppression on NKT cell function required cell-to-cell contact and was mediated via impaired DC maturation. NKT cells cultured under Treg-enriched conditions showed a decrease in CD4^- NKT cell frequency, which exert strong tumoricidal responsiveness upon α-GalCer stimulation. The same results were observed in HNSCC patients with significantly increased effector Tregs.

CONCLUSION

Tregs exert suppressive effects on NKT cell tumoricidal function by inducing more CD4^- NKT cell anergy and less CD4⁺ NKT cell anergy. Both Treg depletion and NKT cell recovery from the anergy state may be important for improving the clinical efficacy of NKT cell-based immunotherapy in patients with advanced cancers.

Circulating T cell subsets are associated with clinical outcome of anti-VEGF-based 1st-line treatment of metastatic colorectal cancer patients: a prospective study with focus on primary tumor sidedness

BACKGROUND

In a prospective study with long-term follow-up, we analyzed circulating T cell subsets in patients with metastatic colorectal cancer (mCRC) in the context of primary tumor sidedness, KRAS status, and clinical outcome. Our primary goal was to investigate whether baseline levels of circulating T cell subsets serve as a potential biomarker of clinical outcome of mCRC patients treated with an anti-VEGF-based regimen.

METHODS

The study group consisted of 36 patients with colorectal adenocarcinoma who started first-line chemotherapy with bevacizumab for metastatic disease. We quantified T cell subsets including Tregs and CD8⁺ T cells in the peripheral blood prior to therapy initiation. Clinical outcome was evaluated as progression-free survival (PFS), overall survival (OS), and objective response rate (ORR).

RESULTS

1) mCRC patients with KRAS wt tumors had higher proportions of circulating CD8⁺ cytotoxic T cells among all T cells but also higher measures of T regulatory (Treg) cells such as absolute count and a higher proportion of Tregs in the CD4⁺ subset. 2) A low proportion of circulating Tregs among CD4⁺ cells, and a high CD8:Treg ratio at initiation of VEGF-targeting therapy, were associated with favorable clinical outcome. 3) In a subset of patients with primarily right-sided mCRC, superior PFS and OS were observed when the CD8:Treg ratio was high.

CONCLUSIONS

The baseline level of circulating immune cells predicts clinical outcome of 1st-line treatment with the anti-VEGF angio/immunomodulatory agent bevacizumab. Circulating immune biomarkers, namely the CD8:Treg ratio, identified patients in the right-sided mCRC subgroup with favorable outcome following treatment with 1st-line anti-VEGF treatment.

Effect of tumor microenvironment on pathogenesis of the head and neck squamous cell carcinoma: a systematic review

The tumor microenvironment (TME) is comprised of many different cell populations, such as cancer-associated fibroblasts and various infiltrating immune cells, and non-cell components of extracellular matrix. These crucial parts of the surrounding stroma can function as both positive and negative regulators of all hallmarks of cancer development, including evasion of apoptosis, induction of angiogenesis, deregulation of the energy metabolism, resistance to the immune detection and destruction, and activation of invasion and metastasis. This review represents a summary of recent studies focusing on describing these effects of microenvironment on initiation and progression of the head and neck squamous cell carcinoma, focusing on oral squamous cell carcinoma, since it is becoming clear that an investigation of differences in stromal composition of the head and neck squamous cell carcinoma microenvironment and their impact on cancer development and progression may help better understand the mechanisms behind different responses to therapy and help define possible targets for clinical intervention.

Secretory High-Mobility Group Box 1 Protein Affects Regulatory T Cell Differentiation in Neuroblastoma Microenvironment In Vitro

Neuroblastoma (NB) is the most common extracranial tumor of childhood with poor prognosis in a high-risk group. An obstacle in the development of treatment for solid tumors is the immunosuppressive nature of the tumor microenvironment (TME). Regulatory T cells (Tregs) represent a T cell subset with specialized function in immune suppression and maintaining self-tolerance. Tregs resident within the tumor milieu is believed to play an important role in immune escape mechanisms. The role of the NB microenvironment in promoting Treg phenotype has never been elucidated. Herein, we demonstrated that the NB microenvironment promoted T cell activation and one NB cell line, SK-N-SH, manifested an ability to induce Treg differentiation. We identified tumor-derived HMGB1 as a potential protein responsible for Treg phenotype induction. By neutralizing HMGB1, Treg differentiation was abolished. Finally, we adopted a dataset of 498 pediatric NB via the NCBI GEO database, accession GSE49711, to validate clinical relevance of HMGB1 overexpression. Up to 11% of patients had HMGB1-overexpressed tumors. Moreover, this patient subpopulation showed higher risks of tumor progression, relapse, or death. Our findings emphasize the importance of immunological signature of tumor cells for appropriate therapeutic approach. Upregulation of secretory HMGB1 may contribute to suppression of antitumor immunity through induction of Tregs in the NB microenvironment.

HLA class II expression on tumor cells and low numbers of tumor-associated macrophages predict clinical outcome in oropharyngeal cancer

Background

Human papillomavirus (HPV)‐positive oropharyngeal squamous cell carcinoma (OPSCC) is a highly immunogenic tumor and differences in tumor microenvironment might contribute to the improved survival of HPV‐positive OPSCC patient.

Methods

A comprehensive multivariate analysis with clinical and immune variables (human leukocyte antigen [HLA] I/II, programmed death ligand 1 (PD‐L1), programmed death receptor 1 (PD1), T cells, and macrophages) was performed in 142 OPSCC patients.

Results

We found an inverse correlation between the expression of HLA class II molecules on tumor cells and CD68+ CD163+ tumor‐associated macrophages (TAMs). High HLA‐DP/DQ/DR expression and low number of TAMs were associated with longer disease‐specific survival and disease‐free survival (DFS). Furthermore, a new population of CD8+ FoxP3+ T cells was correlated with shorter DFS in multivariate analysis.

Conclusions

\We identified new prognostic markers for patients with oropharyngeal cancer, which can be used for selecting patients that can benefit from immunotherapy.

FUT4 is involved in PD-1-related immunosuppression and leads to worse survival in patients with operable lung adenocarcinoma

PURPOSE

As an important glycosyltransferase, fucosyltransferase IV (FUT4) is abnormally upregulated in different types of cancers, but its clinical role remains inexplicit. This work aimed to determine the predictive ability of FUT4 in lung adenocarcinoma (LUAD) after curative resection, as well as to explore the role of a possible FUT4 molecular mechanism on LUAD malignant behavior.

METHODS

A total of 273 LUAD patients after curative resection with complete clinicopathological and RNAseq data from The Cancer Genome Atlas (TCGA) cohort were collected. Correlation of FUT4 with overall survival (OS) was analyzed based on TCGA and further validated by online "Kaplan-Meier Plotter" database and IHC in 70 LUAD patients recruited in the First Hospital of China Medical University cohort. Multivariate Cox regression analysis and 1000 bootstrapping were performed to verify the predictive value of FUT4. Gene set enrichment assay (GSEA) was performed to investigate the biological characteristics. Correlation between PD-1 and FUT4 was analyzed based on TCGA cohort and validated by IHC on cohort from our hospital.

RESULTS

Increased FUT4 expression led to reduced overall survival (OS) of LUAD patients based on TCGA (p = 0.006 and 0.001 for dichotomous and trichotomous modeling, respectively) and externally validated in KMPLOTTER (p = 0.01) and by IHC based on cohort from our hospital (p = 0.005 and p = 0.019 for dichotomous and trichotomous modeling, respectively). FUT4 overexpression was an independent high risk factor for OS along with advanced pT stage and pTNM stage (p = 0.001, p = 0.037, and p < 0.001, respectively). GSEA revealed that FUT4 overexpression might correlate with shortened survival of LUAD patients by promoting cell proliferation via ERBB signaling, and suppressing immune response-related pathways. FUT4 expression positively correlated with PD-1 in TCGA (p = 0.026) and validated by IHC on cohort from our hospital (p = 0.029).

CONCLUSIONS

Increased FUT4 expression led to reduced OS in operable LUAD. FUT4 showed significant correlation with immune response and PD-1 expression.

Deciphering the Role of Regulatory CD4 T Cells in Oral and Oropharyngeal Cancer: A Systematic Review

Background: Recruiting regulatory CD4 T cells (Tregs) into the tumor microenvironment is an important tumor escape mechanism. Diminishing these suppressive cells is therefore one of the targets of cancer immunotherapy. Selective depletion of Tregs has proven successful in enhancing anti-tumor immunity and therapeutic efficacy in multiple tumor types. However, the role of Tregs in oral/oropharyngeal cancers is unclear with conflicting evidence regarding the effect of these suppressive cells on tumor prognosis. In this study, we sought to review the role of Tregs in oral/oropharyngeal cancer with the aim of deciphering the controversy regarding their effect on tumor progression and prognosis.

Methods: A systematic review of the literature pertaining to the role of Tregs in oral/oropharyngeal cancer was performed using Scopus, Embase, and PubMed. Forty-five records were deemed eligible and data describing methodology of Treg detection, tumor type, and association with prognosis were extracted.

Results: Of the 45 eligible manuscripts accepted for this systematic review, thirty-nine studies reported data from human subjects while the remaining studies focused on animal models. Sixteen studies were carried out using peripheral blood samples, while samples from the tumor site were analyzed in 18 studies and 11 studies assessed both blood and tumor samples. The transcriptional factor, Foxp3, was the most commonly used marker for Treg identification (38/45). The findings of 25 studies suggested that an increase in Tregs in the tumor microenvironment and/or peripheral blood was associated with poorer prognosis. These conclusions were attributed to the suppression of immune responses and the consequent tumor progression. Conversely, nine studies showed an increase in Tregs in peripheral blood and/or tumor microenvironment was related to a favorable prognosis, particularly in the presence of human papilloma virus (HPV), the status of which was only assessed in 11 studies.

Conclusions: This review underlines the importance of host immunity in the behavior of oral/oropharyngeal cancer. Furthermore, we report an apparent lack of clarity regarding the true role Tregs play in oral/oropharyngeal cancer progression which could be attributed to inconsistent detection techniques of Tregs. Our results therefore highlight the need for clearer methodologies and more robust phenotyping when defining Tregs.

The role of regulatory T cells in pathogenesis and therapy of human papillomavirus-related diseases, especially in cancer

Human papillomavirus (HPV) is the most common sexually transmitted agent in the world. It can cause condyloma acuminatum, anogenital malignancies, and head and neck cancers. The host immune responses to HPV involve multiple cell types that have regulatory functions, and HPV-mediated changes to regulatory T cells (Tregs) in both the local lesion tissues and the circulatory system of patients have received considerable attention. The role of Tregs in HPV infections ranges from suppression of effector T cell (Teff) responses to protection of tissues from immune-mediated injury in different anatomic subsites. In this review, we explore the influence of Tregs in the immunopathology of HPV-related diseases and therapies targeting Tregs as novel approaches against HPV.

Resistance to Radiotherapy and PD-L1 Blockade Is Mediated by TIM-3 Upregulation and Regulatory T-Cell Infiltration

Purpose: Radiotherapy (RT) can transform the immune landscape and render poorly immunogenic tumors sensitive to PD-L1 inhibition. Here, we established that the response to combined RT and PD-L1 inhibition is transient and investigated mechanisms of resistance.Experimental Design: Mechanisms of resistance to RT and PD-L1 blockade were investigated in orthotopic murine head and neck squamous cell carcinoma (HNSCC) tumors using mass cytometry and whole-genome sequencing. Mice were treated with anti-PD-L1 or anti-TIM-3 alone and in combination with and without RT. Tumor growth and survival were assessed. Flow cytometry was used to assess phenotypic and functional changes in intratumoral T-cell populations. Depletion of regulatory T cells (Treg) was performed using anti-CD25 antibody.Results: We show that the immune checkpoint receptor, TIM-3, is upregulated on CD8 T cells and Tregs in tumors treated with RT and PD-L1 blockade. Treatment with anti-TIM-3 concurrently with anti-PD-L1 and RT led to significant tumor growth delay, enhanced T-cell cytotoxicity, decreased Tregs, and improved survival in orthotopic models of HNSCC. Despite this treatment combination, the response was not durable, and analysis of relapsed tumors revealed resurgence of Tregs. Targeted Treg depletion, however, restored antitumor immunity in mice treated with RT and dual immune checkpoint blockade and resulted in tumor rejection and induction of immunologic memory.Conclusions: These data reveal multiple layers of immune regulation that can promote tumorigenesis and the therapeutic potential of sequential targeting to overcome tumor resistance mechanisms. We propose that targeted Treg inhibitors may be critical for achieving durable tumor response with combined radiotherapy and immunotherapy. Clin Cancer Res; 24(21); 5368-80. ©2018 AACR.

Immunosuppressive property of submandibular lymph nodes in patients with head and neck tumors: differential distribution of regulatory T cells

Objective

Different sensitizations and immune responses are thought to be induced in response to antigens at different mucosal sites between the oral floor and nose. The aim of this study was to investigate differences in the distributions of lymphocyte subsets in the submandibular (SM) and upper jugular (UJ) lymph nodes (LNs), which are supposed to be regional LNs of the oral floor and nasal mucosa, respectively. SMLNs and UJLNs were collected from patients with head and neck tumors who underwent surgical resection. The populations of T cells, Natural Killer (NK) cells, Natural Killer T (NKT) cells, regulatory T cells (Tregs) and dendritic cells (DCs) in LNs without metastasis were analyzed by flow cytometry. The high-affinity IgE receptor (FcεRI) expression of LN cells were also evaluated.

Results

The proportions of CD4⁺CD25⁺Foxp3⁺ Tregs, CD4⁺CD45RA⁻Foxp3^high effector Tregs and FcεRIα⁺CD33⁺CD11c⁺ DCs were significantly larger in SMLNs compared with UJLNs, while those of CD3⁺ T cells, CD3⁻CD56⁺ NK cells, CD3⁺Vα24⁺Vβ11⁺ NKT cells, and CD123⁺CD303⁺ DCs did not show any significant differences between SMLNs and UJLNs. The differential distributions of CD4⁺CD25⁺Foxp3⁺ Tregs were observed regardless of tumor region, LN metastasis and clinical staging. These data indicate that SMLNs may have immunosuppressive properties compared with UJLNs.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3587-z) contains supplementary material, which is available to authorized users.

The Peripheral and Intratumoral Immune Cell Landscape in Cancer Patients: A Proxy for Tumor Biology and a Tool for Outcome Prediction

Functional systemic and local immunity is required for effective anti-tumor responses. In addition to an active engagement with cancer cells and tumor stroma, immune cells can be affected and are often found to be dysregulated in cancer patients. The impact of tumors on local and systemic immunity can be assessed using a variety of approaches ranging from low-dimensional analyses that are performed on large patient cohorts to multi-dimensional assays that are technically and logistically challenging and are therefore confined to a limited sample size. Many of these strategies have been established in recent years leading to exciting findings. Not only were analyses of immune cells in tumor patients able to predict the clinical course of the disease and patients' survival, numerous studies also detected changes in the immune landscape that correlated with responses to novel immunotherapies. This review will provide an overview of established and novel tools for assessing immune cells in tumor patients and will discuss exemplary studies that utilized these techniques to predict patient outcomes.

A minor role of asparaginase in predisposing to cerebral venous thromboses in adult acute lymphoblastic leukemia patients

Cerebral venous thrombosis (CVT) covers up to a third of all venous thromboses (VTs) detected in patients with acute lymphoblastic leukemia (ALL). It usually hampers patients' lives and may also endanger efficient leukemia treatment. Although many factors have been suggested to account for an elevated risk of VTs in patients with ALL, there still is a lack of studies focusing on CVTs and especially in the setting of adult ALL patients. We studied in our retrospective population-based cohort the occurrence, characteristics, as well as risk factors for VTs in 186 consecutively diagnosed Finnish adult ALL patients treated with a national pediatric-inspired treatment protocol ALL2000. In the risk factor analyses for VTs we found a distinction of the characteristics of the patients acquiring CVT from those with other kinds of VTs or without thrombosis. In contrast to previous studies we were also able to compare the effects of asparaginase in relation to CVT occurrence. Notably, more than half of the CVTs were diagnosed prior the administration of asparaginase which accentuates the role of other risk factors on the pathophysiology of CVT compared to truncal or central venous line (CVL) VTs in adult ALL patients.