Elevated frequencies of CD8 T cells expressing PD-1, CTLA-4 and Tim-3 within tumour from perineural squamous cell carcinoma patients

Immunity against Non-Melanoma Skin Cancer and the Effect of Immunosuppressive Medication on Non-Melanoma Skin Cancer Risk in Solid Organ Transplant Recipients

Non-melanoma skin cancers (NMSCs) occur frequently in the Caucasian population and are considered a burden for health care. Risk factors include ultraviolet (UV) radiation, ethnicity and immunosuppression. The incidence of NMSC is significantly higher in solid organ transplant recipients (SOTRs) than in immunocompetent individuals, due to immunosuppressive medication use by SOTRs. While the immunosuppressive agents, calcineurin inhibitors and purine analogues increase the incidence of NMSC in transplant recipients, mTOR inhibitors do not. This is most likely due to the different immunological pathways that are inhibited by each class of drug. This review will focus on what is currently known about the immune response against cutaneous squamous cell carcinoma (cSCC) and basal cell carcinoma (BCC), two of the main types of NMSC. Furthermore, we will describe the different classes of immunosuppressants given to SOTRs, which part of the immune system they target and how they can contribute to NMSC development. The risk of developing NMSC in SOTRs is the result of a combination of inhibiting immunological pathways involved in immunosurveillance against NMSC and the direct (pro/anti) tumor effects of immunosuppressants.

Exhaustion of CD8+ central memory responder T cell differentiation provokes non-melanoma skin cancer in elderly kidney transplant recipients

Introduction

Immunosuppressive therapy prevents graft rejection but increases the risk of non-melanoma skin cancer (NMSC), especially in elderly kidney transplant recipients (KTR).

Methods

In this study, we separately investigated the differentiation of CD8⁺ regulatory T cells (Tregs) and responder T cells (Tresps) between healthy KTR without NMSC, KTR developing de-novo NMSC within two years after the enrolment, and KTR with NMSC at the time of enrolment. Antigen-unexperienced CCR7⁺CD45RA⁺CD31⁺ recent thymic emigrant (RTE) cells differentiate via CD45RA^-CD31⁺ memory (CD31⁺ memory) cells, via resting mature naïve (MN) cells or via direct proliferation into CD45RA^-CD31^- memory (CD31^- memory) cells, consisting of both CCR7⁺CD45RA^- central memory (CM) and CCR7^-CD45RA^- effector memory (EM) cells.

Results

We found that both RTE Treg and Tresp differentiation via CD31⁺ memory Tregs/Tresps was age-independently increased in KTR, who developed de novo NMSC during the follow-up period, causing abundant CM Treg/Tresp production, which may be crucial for cancer immunity. These changes favored a strongly increased CD8⁺ Treg/Tresp ratio, suggesting this ratio as a reliable marker for de-novo NMSC development in KTR. However, with age, this differentiation was replaced by increased conversion of resting MN Tregs/Tresps into CM Tregs/Tresps, which exhausted for Tresps but not for Tregs. In KTR with already existing NMSC at enrolment, differentiation was maintained via conversion and proliferation of resting MN Tregs/Tresps, which however increasingly exhausted with age, especially for Tresps. This resulted in a strong accumulation of terminally differentiated effector memory (TEMRA) Tresps in elderly individuals. Patients with NMSC recurrence showed increased proliferation of resting MN Tregs/Tresps into EM Tregs/Tresps, which tended to exhaust more rapidly, particularly for Tresps, than in patients without NMSC recurrence.

Discussion

In conclusion, we provide evidence that immunosuppressive therapy inhibits differentiation of CD8⁺ Tregs more than that of CD8⁺ Tresps, resulting in an exhausted Tresp profile, thus providing a possible therapeutic approach to improve poor cancer immunity in elderly KTR.

Prognostic value and clinicopathological status of PD-L1 expression and CD8+ TILs in oral squamous cell cancer patients with or without traditional risk factors

BACKGROUND

Non-smokers, non-drinkers, and non-betel quid chewers (NSNDNBs) with oral squamous cell carcinoma (OSCC) have poor survival outcomes. Tumor microenvironment based on PD-L1/CD8+ T cell infiltrated lymphocyte (TIL) proportion is proposed as a prognostic indicator.

METHODS

Immunohistochemistry staining was performed on OSCC samples from 64 patients. The PD-L1/CD8+ TILs were scored and stratified into four groups. Disease-free survival (DFS) was analyzed using a Cox regression model.

RESULTS

OSCC in NSNDNB patients was associated with female sex, T1-2 classification, and PD-L1 positivity. Low CD8+ TILs correlated with perineural invasion. High CD8+ TILs correlated with improved DFS. PD-L1 positivity was not correlated with DFS. Type IV tumor microenvironment yielded the highest DFS (85%).

CONCLUSION

NSNDNB status relates to PD-L1 expression regardless of CD8+ TILs infiltration. Type IV tumor microenvironment was associated with the best DFS. High CD8+ TILs resulted in better survival, while PD-L1 positivity alone was not correlated to DFS.

CD8/PD-L1 immunohistochemical reactivity and gene alterations in cutaneous squamous cell carcinoma

In recent years, several immune checkpoint inhibitors targeting programmed death-ligand 1 (PD-L1) or PD-1 have been developed for cancer therapy. The genetic background of tumors and factors that influence PD-L1 expression in tumor tissues are not yet elucidated in cutaneous squamous cell carcinoma (cSCC). CD8-positive tumor-infiltrating lymphocytes (TILs) are known to be related to tumor immunity. Here, we aimed to study the relationship between CD8/PD-L1 immunohistochemical reactivity and gene alterations in cSCC. Tumorigenic genes were examined to identify gene alterations using next-generation sequencing (NGS). We collected 27 cSCC tissue samples (from 13 metastatic and 14 non-metastatic patients at primary diagnosis). We performed immunohistochemical staining for CD8 and PD-L1, and NGS using a commercially available sequencing panel (Illumina Cancer Hotspot Panel V2) that targets 50 cancer-associated genes. Immunohistochemically, CD8-positive TILs showed a high positive score in cSCC without metastasis; in these cases, cSCC occurred predominantly in sun-exposed areas, the tumor size was smaller, and the total gene variation numbers were notably low. The tumor depth, PD-L1 positivity, and gene variation number with or without tumor metastasis were not related, but the gene variation number tended to be higher in cSCCs arising in non-sun-exposed areas. Tumor metastasis was more common in cSCC arising in non-sun-exposed areas, which decreased the number of TILs or CD8-positive cells. From a genetic perspective, the total gene alterations were higher in cSCC with metastasis. Among them, ERBB4 and NPM1 are presumably involved in cSCC tumorigenesis; in addition, GNAQ, GNAS, JAK2, NRAS, IDH2, and CTNNB1 may be related to tumor metastasis. These results provide information on potential genes that can be targeted for cSCC therapy and on immune checkpoint inhibitors that may be used for cSCC therapy.

Monitoring Pre- and Post-Operative Immune Alterations in Patients With Locoregional Colorectal Cancer Who Underwent Laparoscopy by Single-Cell Mass Cytometry

Surgical excision is currently the principal therapy for locoregional colorectal cancer (CRC). However, surgical trauma leads to controlled tissue damage, causing profound alterations in host immunity and, in turn, affecting post-operative outcomes. Surgery-induced immune alterations in CRC remain poorly defined. Here, single-cell mass cytometry was applied to serial blood samples collected pre-operatively, and on days 1, 3, and 7 post-operatively from 24 patients who underwent laparoscopic surgical resection of CRC to comprehensively monitor the perioperative phenotypic alterations in immune cells and dynamics of immune response. Characterization of immune cell subsets revealed that the post-operative immune response is broad but predominantly suppressive, supported by the decreases in total frequencies of circulating T cells and natural killer (NK) cells, as well as decreased HLA-DR expression on circulating monocytes. The proportion of T cells significantly decreased on day 1 and recovered to the pre-surgical level on day 3 after surgery. The frequency of monocytes was significantly elevated on day 1 after surgery and declined to baseline level on day 3. NK cells temporarily contracted on post-operative day 3. T cells, monocytes, DCs, NK cells, and B cells were partitioned into phenotypically different single-cell clusters. The dynamics of single-cell clusters were different from those of the bulk lineages. T cell clusters in the same response phase fluctuate inconsistently during the perioperative period. Comparing to the baseline levels, the frequencies of CD11b(+)CD33(+)CD14(+)CD16(−) classical monocytes expanded followed by contraction, whereas CD11b(+)CD33(+)CD14(high)CD16(low) intermediate monocytes remained unchanged; HLA-DR expression in monocytes were significantly reduced; the frequencies of intermediate CD56(bright)CD16(+) NK cell subsets increased; and the percentage of memory B lymphocytes were elevated after surgery. Post-operative pro- and anti-inflammatory cytokines were both altered. Furthermore, perioperative immune perturbations in some of the cell subsets were unrecovered within seven days after surgery. Chronological monitoring major immune lineages provided an overview of surgery-caused alterations, including cell augments and contractions and precisely timed changes in immune cell distribution in both innate and adaptive compartments, providing evidence for the interaction between tumor resection and immune modulation.

Immunotherapy for the treatment of perineural spread in cutaneous head and neck squamous cell carcinoma: Time to rethink treatment paradigms

BACKGROUND

Immune checkpoint inhibitors have shown promising antitumour activity. Application in head and neck cutaneous squamous cell carcinoma (cSCC) large nerve perineural spread (PNS) is limited.

METHODS

Retrospective review of 13 patients with PNS receiving anti-PD-1 therapy from September 2017 to May 2021 is presented. Primary endpoints were objective response (complete or partial response) and median time to progression, determined by Head and Neck Multi-Disciplinary Team (MDT) and independent radiology review of magnetic resonance imaging (MRI) and/or computed tomography/positron emission tomography (CT/PET).

RESULTS

Objective response was observed in 9/13 patients (69%), with complete response in 6 (46%) and partial response in 3 patients (23%). Median time to response was 2.1 months (IQR 1.8-2.7 months). There were 3 (23%) patients with progressive disease, with median time to progression of 3.5 months. There were no grade 3-4 treatment related adverse events.

CONCLUSIONS

This case series supports developing evidence for anti-PD-1 checkpoint inhibitor therapy for perineural spread, supporting future prospective clinical trials in this patient population.

Pathophysiological Integration of Metabolic Reprogramming in Breast Cancer

Simple Summary

Tumors exhibit metabolic changes that differentiate them from the normal tissues from which they derive. These metabolic changes favor tumor growth, are primarily induced by cancer cells, and produce metabolic and functional changes in the surrounding stromal cells. There is a close functional connection between the metabolic changes in tumor cells and those that appear in the surrounding stroma. A better understanding of intratumoral metabolic interactions may help identify new vulnerabilities that will facilitate new, more individualized treatment strategies against cancer. We review the metabolic changes described in tumor and stromal cells and their functional changes and then consider, in depth, the metabolic interactions between the cells of the two compartments. Although these changes are generic, we illustrate them mainly with reference to examples in breast cancer.

Abstract

Metabolic changes that facilitate tumor growth are one of the hallmarks of cancer. The triggers of these metabolic changes are located in the tumor parenchymal cells, where oncogenic mutations induce an imperative need to proliferate and cause tumor initiation and progression. Cancer cells undergo significant metabolic reorganization during disease progression that is tailored to their energy demands and fluctuating environmental conditions. Oxidative stress plays an essential role as a trigger under such conditions. These metabolic changes are the consequence of the interaction between tumor cells and stromal myofibroblasts. The metabolic changes in tumor cells include protein anabolism and the synthesis of cell membranes and nucleic acids, which all facilitate cell proliferation. They are linked to catabolism and autophagy in stromal myofibroblasts, causing the release of nutrients for the cells of the tumor parenchyma. Metabolic changes lead to an interstitium deficient in nutrients, such as glucose and amino acids, and acidification by lactic acid. Together with hypoxia, they produce functional changes in other cells of the tumor stroma, such as many immune subpopulations and endothelial cells, which lead to tumor growth. Thus, immune cells favor tissue growth through changes in immunosuppression. This review considers some of the metabolic changes described in breast cancer.

The Tumor Microenvironment in SCC: Mechanisms and Therapeutic Opportunities

Squamous cell carcinoma (SCC) is the second most common skin cancer worldwide and, despite the relatively easy visualization of the tumor in the clinic, a sizeable number of SCC patients are diagnosed at advanced stages with local invasion and distant metastatic lesions. In the last decade, immunotherapy has emerged as the fourth pillar in cancer therapy via the targeting of immune checkpoint molecules such as programmed cell-death protein-1 (PD-1), programmed cell death ligand-1 (PD-L1), and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). FDA-approved monoclonal antibodies directed against these immune targets have provide survival benefit in a growing list of cancer types. Currently, there are two immunotherapy drugs available for cutaneous SCC: cemiplimab and pembrolizumab; both monoclonal antibodies (mAb) that block PD-1 thereby promoting T-cell activation and/or function. However, the success rate of these checkpoint inhibitors currently remains around 50%, which means that half of the patients with advanced SCC experience no benefit from this treatment. This review will highlight the mechanisms by which the immune checkpoint molecules regulate the tumor microenvironment (TME), as well as the ongoing clinical trials that are employing single or combinatory therapeutic approaches for SCC immunotherapy. We also discuss the regulation of additional pathways that might promote superior therapeutic efficacy, and consequently provide increased survival for those patients that do not benefit from the current checkpoint inhibitor therapies.

Cancer Immunotherapy by Blocking Immune Checkpoints on Innate Lymphocytes

Immune checkpoints refer to a plethora of inhibitory pathways of the immune system that play a crucial role in maintaining self-tolerance and in tuning the duration and amplitude of physiological immune responses to minimize collateral tissue damages. The breakdown of this delicate balance leads to pathological conditions, including cancer. Indeed, tumor cells can develop multiple mechanisms to escape from immune system defense, including the activation of immune checkpoint pathways. The development of monoclonal antibodies, targeting inhibitory immune checkpoints, has provided an immense breakthrough in cancer therapy. Immune checkpoint inhibitors (ICI), initially developed to reverse functional exhaustion in T cells, recently emerged as important actors in natural killer (NK)-cell-based immunotherapy. Moreover, the discovery that also helper innate lymphoid cells (ILCs) express inhibitory immune checkpoints, suggests that these molecules might be targeted on ILCs, to modulate their functions in the tumor microenvironment. Recently, other strategies to achieve immune checkpoint blockade have been developed, including miRNA exploiting systems. Herein, we provide an overview of the current knowledge on inhibitory immune checkpoints on NK cells and ILCs and we discuss how to target these innate lymphocytes by ICI in both solid tumors and hematological malignancies.

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.

New immunotherapeutic drugs in advanced non-small cell lung cancer (NSCLC): from preclinical to phase I clinical trials

INTRODUCTION

The development of immune checkpoint inhibitors (ICI) has represented a revolution in the treatment of non-small cell lung cancer (NSCLC) and has established a new standard of care for different settings. However, through adaptive changes, cancer cells can develop resistance mechanisms to these drugs, hence the necessity for novel immunotherapeutic agents.

AREAS COVERED

This paper explores the immunotherapeutics currently under investigation in phase I clinical trials for the treatment of NSCLC as monotherapies and combination therapies. It provides two comprehensive tables of phase I agents which are listed according to target, drug, drug class, mechanism of action, setting, trial identifier, and trial status. A comprehensive literature search was carried out to identify eligible studies from MEDLINE/PubMed and ClinicalTrials.gov.

EXPERT OPINION

A key hurdle to success in this field is our limited understanding of the synergic interactions of the immune targets in the context of the TME. While we can recognize the links between inhibitors and some particularly promising new targets such as TIM-3 and LAG3, we continue to develop approaches to exploit their interactions to enhance the immune response of the patient to tumor cells.

Efficacy of a programmed death-1 checkpoint inhibitor in a case of cutaneous squamous cell carcinoma harboring mutations of TP53 and BRCA2

Immune checkpoint blockades were reported to result in clinical responses in inoperable and metastatic cutaneous squamous cell carcinoma (cSCC). This report describes an 87-year-old woman with recurrent cSCC that was initially responsive to cetuximab (the monoclonal antibody against epithelial growth factor receptor) but eventually became refractory to cetuximab and multiple subsequent salvage chemotherapy regimens. Next-generation sequencing of the tumor discovered three single-nucleotide mutations in TP53, copy number amplification in Src, and a heterozygous deletion in BRCA2. Because of the high mutation burden of her neoplasm (35.2 mutations per megabase), we treated her with a programmed death-1 (PD-1) checkpoint inhibitor, pembrolizumab, for 10 months. The tumor regressed 3 months later and complete pathological remission was achieved 10 months after starting treatment. As of writing, the patient has been disease free for 17 months after discontinuing treatment. This is the first reported case of heterozygous deletion of BRCA2 in cSCC. The high mutation burden and BRCA2 mutation might explain why this tumor was highly sensitive to anti-PD-1 treatment.

Immune Checkpoint Inhibitors in Oral Cavity Squamous Cell Carcinoma and Oral Potentially Malignant Disorders: A Systematic Review

Cancers of the oral cavity cause significant cancer-related death worldwide. While survival rates have improved in recent years, new methods of treatment are being investigated to limit disease progression and to improve outcomes, particularly in oral cavity squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMD). The emerging treatment modality of immunotherapy targets immune checkpoint molecules including PD-1 and its ligand PD-L1, CTLA-4, LAG-3, and TIM-3 to enhance the host immune response against tumours, and to limit the growth and progression of cancer cells. In this systematic review, we searched five databases for keywords pertaining to oral cancers and OPMDs, along with immune checkpoint inhibitors, in order to summarize the current status of their use and efficacy in these diseases. A total of 644 different articles were identified between 2004 and 2019, with 76 deemed suitable for inclusion in the study, providing a total of 8826 samples. Combined results show expression of PD-1 and PD-L1 in the majority of OPMD and OSCC samples, with expression correlating with increased progression and decreased survival rates. Immunotherapy agents pembrolizumab and nivolumab target PD-1 and have been shown to prolong survival rates and improve disease outcomes, especially in combination with chemotherapy or radiotherapy. Despite the equivocal nature of current evidence, there is support for the prognostic and predictive value of immune checkpoint molecules, especially PD-L1, and many studies provide support for the effective use of immune checkpoint inhibitors in the management of OSCC. Limited data is available for OPMD, therefore this should be the focus of future research.

Looking past PD-L1: expression of immune checkpoint TIM-3 and its ligand galectin-9 in cervical and vulvar squamous neoplasia

Immunotherapies targeting the PD-1/PD-L1 pathway have shown some success in cervical and vulvar squamous cell carcinomas, but little is known about the potential vulnerability of these tumors to other checkpoint inhibitors. TIM-3 is a checkpoint molecule that exerts immunosuppressive function via its interaction with Gal-9. TIM-3 and Gal-9 have been identified on a variety of malignancies but have not been studied in cervical and vulvar cancers, nor has their relationship to PD-L1 been established. Sixty-three cervical and vulvar invasive (n = 34) and intraepithelial lesions (n = 29) were assessed for TIM-3, Gal-9, and PD-L1 in tumor/lesional cells and associated immune cells. Tumoral TIM-3 expression was identified in 85% of squamous cell carcinomas but only 21% of intraepithelial lesions (p < 0.0001). When immune cells were also accounted for, 97% of invasive and 41% of intraepithelial lesions had a TIM-3 combined positive score (CPS) ≥ 1 (p < 0.0001). Tumoral membranous expression of Gal-9 was seen in 82% of squamous cell carcinomas and 31% of intraepithelial lesions (p = 0.0001); nearly all cases had Gal-9-positive immune cells. Tumoral PD-L1 was seen in 71% of squamous cell carcinomas and 10% of intraepithelial lesions (p < 0.0001), while the PD-L1 CPS was ≥1 in 82 and 21%, respectively (p < 0.0001). There were no significant differences in TIM-3, GAL-9, or PD-L1 expression in cervical vs. vulvar neoplasms, nor was HPV status significantly associated with any of the three markers. Dual TIM-3/Gal-9 expression was present in the majority (86%) of PD-L1-positive cases including 100% of PD-L1-positive squamous cell carcinomas, suggesting a possible role for TIM-3 checkpoint inhibition in concert with anti-PD-1/PD-L1.

NK Cell-Based Immune Checkpoint Inhibition

Immunotherapy, with an increasing number of therapeutic dimensions, is becoming an important mode of treatment for cancer patients. The inhibition of immune checkpoints, which are the source of immune escape for various cancers, is one such immunotherapeutic dimension. It has mainly been aimed at T cells in the past, but NK cells are a newly emerging target. Simultaneously, the number of checkpoints identified has been increasing in recent times. In addition to the classical NK cell receptors KIRs, LIRs, and NKG2A, several other immune checkpoints have also been shown to cause dysfunction of NK cells in various cancers and chronic infections. These checkpoints include the revolutionized CTLA-4, PD-1, and recently identified B7-H3, as well as LAG-3, TIGIT & CD96, TIM-3, and the most recently acknowledged checkpoint-members of the Siglecs family (Siglec-7/9), CD200 and CD47. An interesting dimension of immune checkpoints is their candidacy for dual-checkpoint inhibition, resulting in therapeutic synergism. Furthermore, the combination of immune checkpoint inhibition with other NK cell cytotoxicity restoration strategies could also strengthen its efficacy as an antitumor therapy. Here, we have undertaken a comprehensive review of the literature to date regarding NK cell-based immune checkpoints.

Current Understanding of the Mechanisms Underlying Immune Evasion From PD-1/PD-L1 Immune Checkpoint Blockade in Head and Neck Cancer

Starting in 2014, large phase III clinical trials began to disclose the study results of using programmed death (PD)-1 immune checkpoint inhibitors (ICIs) (pembrolizumab, nivolumab) and PD-ligand (L)1 (atezolizumab, durvalumab, avelumab) ICIs immunotherapy in patients with advanced head and neck squamous cell carcinoma (HNSCC). In the recurrent and metastatic (R/M), cisplatin-refractory setting, nivolumab achieved a 2.2-fold increase of the median 1-year overall survival as compared with investigators' choice of salvage chemotherapy (36.0 vs. 16.6%). A paradigm shift to the winning regimen, pembrolizumab combined with platinum and infusional fluorouracil, has outperformed the past gold standard of cetuximab-based platinum and fluorouracil combination in terms of overall survival (median, 13.6 vs. 10.1 mo) when administered as the first-line treatment for R/M HNSCC. Nevertheless, many patients still did not respond to the PD-1/PD-L1 checkpoint inhibitor treatment, indicating innate, adapted, or quickly acquired resistance to the immunotherapy. The mechanisms of resistance to ICIs targeting the PD-1/PD-L1 signaling pathway in the context of HNSCC are the focus of this review. The past 5 years have seen improved understanding of the mechanisms underlying checkpoint inhibition resistance in tumor cells, such as: tumor cell adaption with malfunction of the antigen-presenting machinery via class I human leukocyte antigen (HLA), reintroduction of cyclin D-cyclin-dependent kinase (CDK) 4 complex to cell cycles, enrichment of CD44+ cancer stem-like cells, or development of inactivating mutation in IKZF1 gene; impairment of T-cell functions and proliferation through mutations in the interferon-γ-regulating genes, suppression of the stimulator of interferon genes (STING) pathway, or resulted from constitutional nutritional iron deficiency state; metabolic reprogramming by cancer cells with changes in metabolites such as GTP cyclohydrolase 1, tetrahydrobiopterin, kynurenine, indoleamine 2,3-dioxygenase, and arginase 1; defective dendritic cells, CD-69 sufficient state; and the upregulation or activation of the alternative immune checkpoints, including lymphocyte activation gene-3 (LAG3), T-cell immunoglobulin and ITIM domain (TIGIT)/CD155 pathway, T-cell immunoglobulin mucin-3 (TIM-3), and V domain-containing Ig suppressor of T-cell activation (VISTA). Several potential biomarkers or biosignatures, which could predict the response or resistance to the PD-1/PD-L1 checkpoint immunotherapy, are also discussed.

PD-L1/PD1 Expression, Composition of Tumor-Associated Immune Infiltrate, and HPV Status in Conjunctival Squamous Cell Carcinoma

Purpose

Conjunctival squamous cell carcinoma (SCC), a type of ocular surface neoplasia, is primarily treated by surgical resection and topical immuno- or chemotherapy. Metastatic disease may be treated with systemic chemo- or immunotherapy, albeit with variable response. The purpose of this study was to determine whether immune checkpoint blockade might be considered in the management of conjunctival SCC.

Methods

In this retrospective study, we evaluated tumor programmed death-ligand 1 (PD-L1) expression, high-risk human papillomavirus (HPV) status, and immunohistochemical expression of cluster of differentiation 3 (CD3), cluster of differentiation 8 (CD8), and programmed death 1 (PD1) in tumor-associated immune infiltrate in a series of 31 conjunctival SCCs.

Results

PD-L1 expression in ≥1% of tumor cells was noted in 14 conjunctival SCCs (47%) and was more prevalent in invasive than in situ SCC and among tumors with higher American Joint Committee on Cancer (AJCC) T category (≥T3 versus ≤T2). The density of CD3-positive T cells was higher in primary than recurrent tumors and higher in invasive than in situ tumors. Density of CD3-positive and CD8-positive T cells was higher in higher AJCC stage tumors. Density of CD8-positive T cells was higher in HPV-positive than HPV-negative tumors. PD-L1 expression correlated with a higher density of CD3-, CD8-, and PD1-positive cells in the tumor-associated immune infiltrate but not with HPV status.

Conclusions

Our findings demonstrate that PD-L1 is expressed in almost half of conjunctival SCCs. The density of tumor-associated immune cells correlated with invasive SCC, stage, and HPV status in conjunctival SCC. Our findings support further studies to establish the potential application of immune checkpoint blockade in the management of conjunctival SCC.

The Role of the Immune System in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer. In immunosuppressed populations it is a source of considerable morbidity and mortality due to its enhanced recurrence and metastatic potential. In common with many malignancies, leucocyte populations are both protective against cancer development and also play a role in 'sculpting' the nascent tumor, leading to loss of immunogenicity and tumor progression. UV radiation and chronic viral carriage may represent unique risk factors for cSCC development, and the immune system plays a key role in modulating the response to both. In this review, we discuss the lessons learned from animal and ex vivo human studies of the role of individual leucocyte subpopulations in the development of cutaneous SCC. We then discuss the insights into cSCC immunity gleaned from studies in humans, particularly in populations receiving pharmacological immunosuppression such as transplant recipients. Similar insights in other malignancies have led to exciting and novel immune therapies, which are beginning to emerge into the cSCC clinical arena.

Combined Next-generation Sequencing and Flow Cytometry Analysis for an Anti-PD-L1 Partial Responder over Time: An Exploration of Mechanisms of PD-L1 Activity and Resistance in Bladder Cancer

Anti-PD-L1/PD-1 immunotherapy has improved survival for certain patients with metastatic urothelial carcinoma. However, the mechanisms of resistance to these agents have not been fully elucidated. We report the first combined analysis using RNA sequencing, whole-exome sequencing (WES), and flow cytometry of multiple tumor specimens over a 5-yr period for a patient undergoing anti-PD-L1 therapy. Initial sensitivity to anti-PD-L1 immunotherapy was associated with conversion to a basal molecular subtype and a rising tumor mutational burden. We found that as the tumor became more resistant to anti-PD-L1, the proportion of regulatory T cells and CD8⁺ T cells expressing alternative immune checkpoints including CTLA-4, TIM-3, and LAG-3 increased. This suggests that alternative immune checkpoint upregulation may be one form of anti-PD-L1 resistance in urothelial carcinoma. These data support the concept of combined immune checkpoint blockade for urothelial carcinoma, a concept that is being evaluated in prospective clinical trials. PATIENT SUMMARY: In this study we characterized how a patient with metastatic urothelial cancer became resistant to anti-PD-L1 immunotherapy. By tracking changes in protein and gene expression over time, we found that as urothelial carcinoma becomes resistant to PD-L1 blockade, additional immune checkpoints may be upregulated. These data support the concept of combined checkpoint blockade for urothelial carcinoma.

A gene expression profile associated with perineural invasion identifies a subset of HNSCC at risk of post-surgical recurrence

OBJECTIVES

Perineural invasion (PNI) is a common histopathological finding in head and neck squamous cell carcinoma (HNSCC). We aimed to explore the molecular mechanisms involved in PNI and the role of PNI as an aggressive pathological feature.

MATERIALS AND METHODS

We used data from The Cancer Genome Atlas (TCGA) to relate the histological presentation of 528 HNSCC tumours to clinical, whole genome expression and proteomic data.

RESULTS

We identified a specific gene expression profile highly enriched in genes related to muscle differentiation/function and associated with PNI in HNSCC. We explored the clinical significance of this profile in three groups of HNSCC tumours stratified according to their low, intermediate or high risk of post-surgical recurrence. In the "low-risk" group, defined as tumours indicated for surgery without adjuvant radiotherapy (n = 51), the PNI gene expression profile identified a subset of HNSCC with a higher rate of tumour recurrence, decreased Disease Free Survival (DFS) and Overall Survival (OS) (p < 0.0001 and p = 0.0064, respectively). Comparable results were observed in "intermediate risk" tumours (n = 112), but not in "high risk" tumours (n = 147), whose prognosis was driven by the presence of lymph node extracapsular spread. Finally, we found that tumours with histological PNI had increased activation levels of the Akt/PKB and mTOR (mammalian Target Of Rapamycin) kinases.

CONCLUSION

PNI is characterised by a specific gene expression profile and distinct biological characteristics. Analysing the PNI gene expression profile holds potential for therapeutic stratification of HNSCC and identification of a subset of tumours with a higher risk of recurrence.

T-lymphocyte profiles differ between keratoacanthomas and invasive squamous cell carcinomas of the human skin

BACKGROUND

T-lymphocytes are involved in tumor progression and regression. Actinic keratoses (AK) are atypical proliferations of keratinocytes of the skin. Some AK progress into invasive cutaneous squamous cell carcinomas (cSCC). Keratoacanthomas (KA) are either classified as a cSCC subtype or a benign tumor with histologic resemblance to well-differentiated cSCC as it is supposed to regress spontaneously. In contrast, cSCC represent malignant tumors that may metastasize.

OBJECTIVES

To compare the T-lymphocyte profiles of AK, KA and cSCC in relation to PD-L1 expression.

METHODS

Tissue micro-arrays of 103 cases of AK, 43 cases of KA and 106 cases of cSCC were stained by immunohistochemistry for E-cadherin, CD3, CD4, CD8, FOXp3, and the receptor-ligand pair PD-1/PD-L1. Immunohistological scores were computationally determined to assess PD-L1 expression as well as the expression profiles of T-lymphocytes.

RESULTS

AK had lower numbers of CD3+ and PD-1+ cells compared to KA and lower numbers of CD3+, CD8+ and PD-1+ cells in comparison with cSCC. KA showed significantly higher numbers of CD4+ and FOXp3+ cells as well as lower numbers of CD8+ cells in comparison with invasive cSCC. cSCC expressed significantly more PD-L1 in comparison with AK and KA. Among cSCC PD-L1 expression was higher in moderately and poorly-differentiated cSCC than in well-differentiated cSCC. Increased PD-L1 expression also correlated with increased numbers of CD4+, CD8+ and FOXp3+ cells in cSCC.

CONCLUSIONS

Tumor-associated T-lymphocyte infiltrates showed significant differences between AK, KA and invasive cSCC. PD-L1 expression correlated with invasion of T-cell infiltrates in invasive cSCC.

CXCR4 and PD-1 Expression in Head and Neck Cancer with Perineural Spread

Background  Perineural spread (PNS) is a marker of aggressiveness and has been shown to occur in cranial nerves due to advanced mucosal and cutaneous head and neck cancer. Receptors CXC chemokine receptor 4 (CXCR4) and programmed cell death-1 (PD-1) have been shown to be overexpressed in a variety of cancers with PNS, with the inhibition of these pathways offering a potential future treatment. Methods  Retrospective immunohistochemical staining for the CXCR4 and PD-1 receptors was performed on 28 head and neck specimens that demonstrated PNS from January 2017 to August 2017, at Royal Brisbane and Women's Hospital, Brisbane, Australia. Results  CXCR4 staining was positive in 52 and 60% of the squamous cell carcinoma (SCC) and adenoid cystic carcinoma PNS specimens, respectively. Cutaneous SCC tumors with no PNS stained positively in 33%. No significant staining for PD-1 in peritumoral lymphocytes or tumor specimens was seen. Conclusion  CXCR4 is overexpressed in advanced skin cancer and head and neck tumors that demonstrated PNS to large cranial nerves. Overall, these results provide strong support for using CXCR4 as a biomarker and further investigation of immunotherapeutic agents that could inhibit tumor progression via targeting CXCR4 expression.

Next generation immune-checkpoints for cancer therapy

The discovery and clinical application of immune-checkpoint inhibitors has dramatically improved the treatments, outcomes and therapeutic concepts in multiple tumor settings. This breakthrough was mainly based on monoclonal antibodies blocking the inhibitory molecule CTLA-4 and or the PD-1/PD-L1 axis, with the aim of counteracting major tumor immune evasion mechanisms. Even acknowledging these important successes, not all the patients benefit from these treatments. Translational and clinical research efforts are ongoing to explore the potentialities of a new generation of immune-modulatory molecules to extend current clinical applications and contrast the unsolved issues of resistance and disease relapse that still affects a considerable rate of patients. New immune-checkpoints, with either stimulatory or inhibitory functions are emerging with key roles in regulating T cell response but also affecting other crucial effectors belonging to the innate immune response (e.g., natural killer). Their therapeutic exploitation, either alone or in strategical combinations, is providing important preclinical results, holding promises currently explored in initial clinical trials. The first results point toward favorable safety profiles with selective hints of activity in challenging settings. Important issues regarding the dose, schedule and rational combinations remain open and data from the clinical studies are needed. Here we provide an overview of the main emerging stimulatory or inhibitory immune-checkpoints exploitable in cancer treatment, briefly reporting their biological function, preclinical activity and preliminary clinical data.

MicroRNA-374b inhibits liver cancer progression via down regulating programmed cell death-1 expression on cytokine-induced killer cells

Programmed cell death-1 (PD-1) is an oncogene associated with suppressing proliferation and cytokine production of T cells in the progression of liver cancer. microRNAs (miRs) regulate gene expression via specific binding to the target 3′untranslated region of mRNA. In the present study, miR-374b was indicated to interact with PD-1 and affect the tumor-targeting capacity of cytokine-induced killer (CIK) cells. miR-374b inhibitor significantly increased PD-1 expression in CIK cells. A synthetic small interfering (si)RNA targeting PD-1 was employed to silence the expression level of PD-1 in CIK cells. Then, the antitumor effect of siPD-1 in CIK cells was investigated. In vitro study demonstrated that IFN-γ secretion and the concentration of lactate dehydrogenase were significantly increased in the PD-1 knockdown group; however, the viability of HepG2 cells in the PD-1 knockdown group had significantly decreased, compared with the HepG2 cells in the negative control group. In vivo study indicated that mice inoculated with HepG2 cells and CIK cells with PD-1 knocked down had a significantly smaller tumor volume, compared with the control group. To conclude, human CIK cells transfected with siPD-1 can target liver cancer cells and enhance immunotherapy efficacy, and therefore they have potential in the immunotherapy of liver cancer.

Control of NK Cell Activation by Immune Checkpoint Molecules

The development of cancer and chronic infections is facilitated by many subversion mechanisms, among which enhanced expression of immune checkpoints molecules, such as programmed death-1 (PD-1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), on exhausted T cells. Recently, immune checkpoint inhibitors have shown remarkable efficiency in the treatment of a number of cancers. However, expression of immune checkpoints on natural killer (NK) cells and its functional consequences on NK cell effector functions are much less explored. In this review, we focus on the current knowledge on expression of various immune checkpoints in NK cells, how it can alter NK cell-mediated cytotoxicity and cytokine production. Dissecting the role of these inhibitory mechanisms in NK cells is critical for the full understanding of the mode of action of immunotherapies using checkpoint inhibitors in the treatment of cancers and chronic infections.

Emerging targets in cancer immunotherapy

The first generation of immune checkpoint inhibitors (anti-CTLA-4 and anti-PD-1/PD-L1) targeted natural immune homeostasis pathways, co-opted by cancers, to drive anti-tumor immune responses. These agents led to unprecedented results in patients with previously incurable metastatic disease and may become first-line therapies for some advanced cancers. However, these agents are efficacious in only a minority of patients. Newer strategies are becoming available that target additional immunomodulatory mechanisms to activate patients' own anti-tumor immune responses. Herein, we present a succinct summary of emerging immune targets with reported pre-clinical efficacy that have progressed to active investigation in clinical trials. These emerging targets include co-inhibitory and co-stimulatory markers of the innate and adaptive immune system. In this review, we discuss: 1) T lymphocyte markers: Lymphocyte Activation Gene 3 [LAG-3], T-cell Immunoglobulin- and Mucin-domain-containing molecule 3 [TIM-3], V-domain containing Ig Suppressor of T cell Activation [VISTA], T cell ImmunoGlobulin and ITIM domain [TIGIT], B7-H3, Inducible T-cell Co-stimulator [ICOS/ICOS-L], CD27/CD70, and Glucocorticoid-Induced TNF Receptor [GITR]; 2) macrophage markers: CD47/Signal-Regulatory Protein alpha [SIRPα] and Indoleamine-2,3-Dioxygenase [IDO]; and 3) natural killer cell markers: CD94/NKG2A and the Killer Immunoglobulin-like receptor [KIR] family. Finally, we briefly highlight combination strategies and potential biomarkers of response and resistance to these cancer immunotherapies.