Quercetin Limits Tumor Immune Escape through PDK1/CD47 Axis in Melanoma

Quercetin (3,3[Formula: see text],4[Formula: see text],5,7-pentahydroxyflavone) is a bioactive plant-derived flavonoid, abundant in fruits and vegetables, that can effectively inhibit the growth of many types of tumors without toxicity. Nevertheless, the effect of quercetin on melanoma immunology has yet to be determined. This study aimed to investigate the role and mechanism of the antitumor immunity action of quercetin in melanoma through both in vivo and in vitro methods. Our research revealed that quercetin has the ability to boost antitumor immunity by modulating the tumor immune microenvironment through increasing the percentages of M1 macrophages, CD8[Formula: see text] T lymphocytes, and CD4[Formula: see text] T lymphocytes and promoting the secretion of IL-2 and IFN-[Formula: see text] from CD8[Formula: see text] T cells, consequently suppressing the growth of melanoma. Furthermore, we revealed that quercetin can inhibit cell proliferation and migration of B16 cells in a dose-dependent manner. In addition, down-regulating PDK1 can inhibit the mRNA and protein expression levels of CD47. In the rescue experiment, we overexpressed PDK1 and found that the protein and mRNA expression levels of CD47 increased correspondingly, while the addition of quercetin reversed this effect. Moreover, quercetin could stimulate the proliferation and enhance the function of CD8[Formula: see text] T cells. Therefore, our results identified a novel mechanism through which CD47 is regulated by quercetin to promote phagocytosis, and elucidated the regulation of quercetin on macrophages and CD8[Formula: see text] T cells in the tumor immune microenvironment. The use of quercetin as a therapeutic drug holds potential benefits for immunotherapy, enhancing the efficacy of existing treatments for melanoma.

Recent Advances in the Development of Non-Invasive Imaging Probes for Cancer Immunotherapy

The last two decades have witnessed a major revolution in the field of tumor immunology including clinical progress using various immunotherapy strategies. These advances have highlighted the potential for approaches that harness the power of the immune system to fight against cancer. While cancer immunotherapies have shown significant clinical successes, patient responses vary widely due to the complex and heterogeneous nature of tumors and immune responses, calling for reliable biomarkers and therapeutic strategies to maximize the benefits of immunotherapy. Especially, stratifying responding individuals from non-responders during the early stages of treatment could help avoid long-term damage and tailor personalized treatments. In efforts to develop non-invasive means for accurately evaluating and predicting tumor response to immunotherapy, multiple affinity-based agents targeting immune cell markers and checkpoint molecules have been developed and advanced to clinical trials. In addition, researchers have recently turned their attention to substrate and activity-based imaging probes that can provide real-time, functional assessment of immune response to treatment. Here, we highlight some of those recently designed probes that image functional proteases as biomarkers of cancer immunotherapy with a focus on their chemical design and detection modalities and discuss challenges and opportunities for the development of imaging tools utilized in cancer immunotherapy.

The Role of Traditional Chinese Medicine in Cancer Immunotherapy: Current Status and Future Directions

The tumor microenvironment (TME) plays an important role in the development of tumors. Immunoregulatory cells and cytokines facilitate cancer cells to avoid immune surveillance. Overexpression of immune checkpoint molecules such as CTLA-4 and PD-1/PD-L1 inhibits immune function and enables cancer cells to avoid clearance by the immune system. Thus, minimizing tumor immunosuppression could be an important strategy for cancer therapy. Currently, many immune checkpoint-targeted drugs, such as PD-1/PD-L1 inhibitors, have been approved for marketing and have shown unique advantages in the clinical treatment of cancers. The concept of "strengthening resistance to eliminate pathogenic factors" in traditional Chinese medicine (TCM) is consistent with the immunotherapy of cancer. According to previous studies, the role of TCM in tumor immunotherapy is mainly associated with the positive regulation of natural killer cells, CD8/CD4 T cells, dendritic cells, M2 macrophages, interleukin-2, tumor necrosis factor-[Formula: see text], and IFN-[Formula: see text], as well as with the negative regulation of Tregs, myeloid-derived suppressor cells, cancer-associated fibroblasts, PD-1/PD-L1, transforming growth factor-[Formula: see text], and tumor necrosis factor-[Formula: see text]. This paper summarizes the current research on the effect of TCM targeting the TME, and further introduces the research progress on studying the effects of TCM on immune checkpoints. Modern pharmacological studies have demonstrated that TCM can directly or indirectly affect the TME by inhibiting the overexpression of immune checkpoint molecules and enhancing the efficacy of tumor immunotherapy. TCM with immunomodulatory stimulation could be the key factor to achieve benefits from immunotherapy for patients with non-inflammatory, or "cold", tumors.

Updates in toxicities associated with immune checkpoint inhibitors

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have become a pillar of treatment for numerous cancers with increasing use in combination with other ICIs and in earlier stages of disease treatment. Although effective, ICI use is accompanied by a milieu of potentially bothersome or even life-threatening toxicities known as immune-related adverse events (irAEs), necessitating careful monitoring and early intervention.

AREAS COVERED

In this review, we provide an overview of recent advances surrounding toxicity pathophysiology and treatment in the context of relevant organ systems. An emphasis on current treatments by toxicity, as well as updates on steroid-refractory toxicities, chronic toxicities, and biomarkers will be a focus of this update on the current understanding of irAEs.

EXPERT OPINION

ICI toxicities are a major limitation on the deployment of multi-agent ICI regimens and are thus a major priority to understand, treat, and prevent. Recent developments have led to greater understanding of the pathophysiology of these events, which may lead to improved prevention or mitigation strategies. Further, early studies have also suggested steroid-sparing approaches that may be useful. Ultimately, preventing and managing irAEs will be a key goal toward successful ICI treatment across a broader range of patients with cancer.

Oxaliplatin-Resistant Hepatocellular Carcinoma Drives Immune Evasion Through PD-L1 Up-Regulation and PMN-Singular Recruitment

BACKGROUND & AIMS

Previously, we showed the inhibitor of differentiation or DNA binding 1 (ID1)/Myc signaling is highly expressed in oxaliplatin-resistant hepatocellular carcinoma (HCC). This study sought to investigate the role of ID1/Myc signaling on immune evasion in oxaliplatin-resistant HCC.

METHODS

The oxaliplatin (OXA)-resistant HCC cell lines (Hepa 1-6-OXA, 97H-OXA, and 3B-OXA) were established and their oxaliplatin tolerance was confirmed in vitro and in vivo. The relationship between ID1/Myc and programmed death-ligand 1 (PD-L1) up-regulation and polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC) accumulation was explored. The underlying mechanism in which ID1/Myc signaling regulated PD-L1 expression and PMN-MDSC accumulation was investigated in vitro and vivo.

RESULTS

Increased ID1/Myc expression was identified in oxaliplatin-resistant HCC and correlated with PD-L1 up-regulation and PMN-MDSC accumulation. The knockdown of Myc sensitized oxaliplatin-resistant HCC cells to oxaliplatin and resulted in a decrease of PMN-MDSCs and an increase of interferon-γ⁺ CD8⁺ T cells in a tumor microenvironment. Polymerase chain reaction array, enzyme-linked immunosorbent assay, and MDSC Transwell migration assay indicated that oxaliplatin-resistant HCC cells recruited PMN-MDSCs through chemokine (C-C motif) ligand 5 (CCL5). The dual luciferase reporter assay and chromatin immunoprecipitation assay indicated that Myc could directly increase the transcriptions of PD-L1 and CCL5. Furthermore, anti-PD-L1 antibody combined with CCL5 blockade showed significant antitumor effects in oxaliplatin-resistant HCC.

CONCLUSIONS

ID1/Myc signaling drives immune evasion in oxaliplatin-resistant HCC via PD-L1 up-regulation and PMN-MDSC recruitment. Blocking the ID1/Myc-induced immune tolerance represents a promising treatment target to conquer chemoresistance in HCC.

Cordycepin enhances anti-tumor immunity in colon cancer by inhibiting phagocytosis immune checkpoint CD47 expression

Cordycepin, also known as 3'-deoxyadenosine, is an extract from Cordyceps militaris, which has been reported as an anti-inflammation and anti-tumor substance without toxicity. However, the pharmacological mechanism of Cordycepin on tumor immunity under its anti-tumor effect has not yet been elucidated. Herein, we investigated Cordycepin's anti-tumor effect on colon cancer both in vitro and in vivo. Our results show that Cordycepin can inhibit growth, migration, and promoted apoptosis of CT26 cells in a dose-dependent manner. Cordycepin suppressed the growth of colon cancer in mouse subcutaneous tumor model by modulating tumor immune microenvironment where CD4⁺ T, CD8⁺ T, M1 type macrophages, NK cells were up-regulated. Further investigations revealed that Cordycepin inhibited phagocytosis immune checkpoint CD47 protein expression by reducing BNIP3 expression. In addition, Cordycepin also inhibited the expression of TSP1 in tumor cells and Jurkat cells, which may reduce the binding of TSP1 to CD47, thereby reducing T cell apoptosis and allowing more T cells to infiltrate into tumors. And in vitro co-culture experiments proved that Cordycepin could enhance the phagocytosis of CT26 cells by macrophages. These results explained the underlying mechanism of the anti-tumor immunity of Cordycepin. In conclusion, our results identify a novel mechanism by which Cordycepin inhibits phagocytosis immune checkpoint CD47 in tumor cells to promote tumor cells phagocytosis of macrophages. Cordycepin may be able to serve as a more effective immunotherapeutic drug against colon cancer.

PD-L1 Expression in Circulating Tumor Cells as a Promising Prognostic Biomarker in Advanced Non-small-cell Lung Cancer Treated with Immune Checkpoint Inhibitors

BACKGROUND

Circulating tumor cells (CTCs) are a promising source of biological information in cancer. Data correlating PD-L1 expression in CTCs with patients' response to immune checkpoint inhibitors (ICIs) in non-small-cell lung cancer (NSCLC) are still lacking.

METHODS

This is a prospective single-center cohort study enrolling patients with advanced NSCLC. CTCs were identified and counted with the CellSearch system. PD-L1 expression on CTCs was assessed with phycoerythrin-conjugated anti-human PD-L1 antibody, clone MIH3 (BioLegend, USA). Primary endpoint was the correlation between the CTCs PD-L1 expression and overall survival (OS). Among secondary objectives, we evaluated the correlation between PD-L1 expression on CTCs and matched tumor tissue and the correlation of CTC number and baseline tumor size (BTS).

RESULTS

Thirty-nine patients treated with anti-PD-1/PD-L1 agents as second- or third-line therapy were enrolled. Patients were divided into 3 groups: no CTC detectable (CTCnull, n = 15), PD-L1 positive CTC (CTCpos, n = 13), and PD-L1 negative CTC (CTCneg, n = 11). Median OS in patients with CTCneg was 2.2 months, 95% confidence interval (CI), 0.8-3.6 (reference) versus 3.7 months, 95% CI, 0.1-7.5 (hazard ratio [HR] 0.33; 95% CI, 0.13-0.83; P = .019) in patients with CTCpos versus 16.0 months, 95% CI, 2.2-29.8 (HR 0.17; 95% CI, 0.06-0.45; P< .001) in patients with CTCnull. No correlation was found between PD-L1 expression on CTCs and on tumor tissue. CTC number was correlated with BTS.

CONCLUSION

PD-L1 expression on CTCs is a promising biomarker in patients with NSCLC treated with ICIs. Further validation as predictive biomarker is needed.

[Prognostic and predictive methylation biomarkers in HNSCC : Epigenomic diagnostics for head and neck squamous cell carcinoma (HNSCC)]

BACKGROUND

Prognostic and predictive biomarkers for personalized treatment management in head and neck squamous cell carcinoma (HNSCC) are of great clinical interest.

OBJECTIVE

DNA methylation is an epigenetic process involved in gene regulation and could be a source of potential prognostic and predictive biomarkers.

METHODS

This study comprises literature research in PubMed and own studies.

RESULTS

Gene methylation, e.g. of PITX2, is a strong, human papillomavirus (HPV)-independent prognostic biomarker. SHOX2 and SEPT9 methylation in circulating cell-free DNA within blood plasma correlates with tumor stage and prognosis. Methylation of diverse immune checkpoints, e.g., PD‑1, PD-L1, and CTLA4, is also prognostic and correlates with gene expression.

CONCLUSION

DNA methylation is a source of efficient prognostic blood plasma- and tissue-based biomarkers. However, prior to clinical implementation, studies must prove that biomarker-guided treatment selection can lead to better outcomes or reduced toxicity. The applicability of DNA methylation as a predictive biomarker for targeted drug-based cancer therapy seems promising, although further validation is needed.

Common gamma chain cytokines and CD8 T cells in cancer

Overcoming exhaustion-associated dysfunctions and generating antigen-specific CD8 T cells with the ability to persist in the host and mediate effective long-term anti-tumor immunity is the final aim of cancer immunotherapy. To achieve this goal, immuno-modulatory properties of the common gamma-chain (γ_c) family of cytokines, that includes IL-2, IL-7, IL-15 and IL-21, have been used to fine-tune and/or complement current immunotherapeutic protocols. These agents potentiate CD8 T cell expansion and functions particularly in the context of immune checkpoint (IC) blockade, shape their differentiation, improve their persistence in vivo and alternatively, influence distinct aspects of the T cell exhaustion program. Despite these properties, the intrinsic impact of cytokines on CD8 T cell exhaustion has remained largely unexplored impeding optimal therapeutic use of these agents. In this review, we will discuss current knowledge regarding the influence of relevant γ_c cytokines on CD8 T cell differentiation and function based on clinical data and preclinical studies in murine models of cancer and chronic viral infection. We will restate the place of these agents in current immunotherapeutic regimens such as IC checkpoint blockade and adoptive cell therapy. Finally, we will discuss how γ_c cytokine signaling pathways regulate T cell immunity during cancer and whether targeting these pathways may sustain an effective and durable T cell response in patients.

Recent advances in understanding immune phenotypes of thyroid carcinomas: prognostication and emerging therapies

Tumors modulate the host immune cells within their microenvironment to avoid recognition and elimination by our immune system, a phenotype called cancer immune escape. Different mechanisms responsible for cancer immune escape that result either in decreased tumor immunogenicity or in increased tumor immunosuppressive activity have been identified. Recently, various immunotherapeutic approaches have been developed with the aim to revert tumor immune escape. The aims of this review are to explore the immunological aspects of thyroid cancer and to assess whether these features can be exploited in the prognosis and treatment of advanced forms of this disease. Therefore, we will describe the immune landscape and phenotypes of thyroid cancer, summarize studies investigating the expression of immunomodulatory molecules, and finally describe the preclinical and clinical trials investigating the utility of immunotherapies in the management of thyroid cancer.

The aim of this review is to explore the immunological aspects of thyroid cancer and to assess whether these features can be exploited in the prognosis and treatment of advanced forms of this disease. Therefore, we will describe the immune-landscape and phenotypes of thyroid cancer, we will summarize studies investigating the expression of immunomodulatory molecules, and we will finally describe the preclinical and clinical trials investigating the utility of immunotherapies in the management of thyroid cancer.

Identification of an Immune-specific Class of Hepatocellular Carcinoma, Based on Molecular Features

BACKGROUND & AIMS

Agents that induce an immune response against tumors by altering T-cell regulation have increased survival times of patients with advanced-stage tumors, such as melanoma or lung cancer. We aimed to characterize molecular features of immune cells that infiltrate hepatocellular carcinomas (HCCs) to determine whether these types of agents might be effective against liver tumors.

METHODS

We analyzed HCC samples from 956 patients. We separated gene expression profiles from tumor, stromal, and immune cells using a non-negative matrix factorization algorithm. We then analyzed the gene expression pattern of inflammatory cells in HCC tumor samples. We correlated expression patterns with the presence of immune cell infiltrates and immune regulatory molecules, determined by pathology and immunohistochemical analyses, in a training set of 228 HCC samples. We validated the correlation in a validation set of 728 tumor samples. Using data from 190 tumors in the Cancer Genome Atlas, we correlated immune cell gene expression profiles with numbers of chromosomal aberrations (based on single-nucleotide polymorphism array) and mutations (exome sequence data).

RESULTS

We found approximately 25% of HCCs to have markers of an inflammatory response, with high expression levels of the CD274 molecule (programmed death-ligand 1) and programmed cell death 1, markers of cytolytic activity, and fewer chromosomal aberrations. We called this group of tumors the Immune class. It contained 2 subtypes, characterized by markers of an adaptive T-cell response or exhausted immune response. The exhausted immune response subclass expressed many genes regulated by transforming growth factor beta 1 that mediate immunosuppression. We did not observe any differences in numbers of mutations or expression of tumor antigens between the immune-specific class and other HCCs.

CONCLUSIONS

In an analysis of HCC samples from 956 patients, we found almost 25% to express markers of an inflammatory response. We identified 2 subclasses, characterized by adaptive or exhausted immune responses. These findings indicate that some HCCs might be susceptible to therapeutic agents designed to block the regulatory pathways in T cells, such as programmed death-ligand 1, programmed cell death 1, or transforming growth factor beta 1 inhibitors.

[Immune checkpoint inhibitor therapy in advanced head and neck cancer]

Immune checkpoint inhibitor therapy, which targets regulatory pathways in T cells to enhance antitumor immune responses, improves the life quality of cancer patients and has joined the ranks of surgery, radiation, and chemotherapy to become a major choice for cancer therapy. Over the past few years, multiple exciting results have been obtained on checkpoint inhibitor therapy in advanced head and neck cancer. However, questions such as patient selection and biomarkers for assessing the therapy are largely unsolved. Herein, we briefly review recent findings in checkpoint inhibitor therapy for advanced head and neck cancer. We will also discuss possible mechanism, safety, combination therapy, and side effects for the therapy. Checkpoint inhibitor therapy has led to important clinical advances and will provide a new weapon against cancer.