Comprehensive insights into the effects and regulatory mechanisms of immune cells expressing programmed death-1/programmed death ligand 1 in solid tumors

Repurposing drugs for solid tumor treatment: focus on immune checkpoint inhibitors

Cancer remains a significant global health challenge with limited treatment options beyond systemic therapies, such as chemotherapy, radiotherapy, and molecular targeted therapy. Immunotherapy has emerged as a promising therapeutic modality but the efficacy has plateaued, which therefore provides limited benefits to patients with cancer. Identification of more effective approaches to improve patient outcomes and extend survival are urgently needed. Drug repurposing has emerged as an attractive strategy for drug development and has recently garnered considerable interest. This review comprehensively analyses the efficacy of various repurposed drugs, such as transforming growth factor-beta (TGF-β) inhibitors, metformin, receptor activator of nuclear factor-κB ligand (RANKL) inhibitors, granulocyte macrophage colony-stimulating factor (GM-CSF), thymosin α1 (Tα1), aspirin, and bisphosphonate, in tumorigenesis with a specific focus on their impact on tumor immunology and immunotherapy. Additionally, we present a concise overview of the current preclinical and clinical studies investigating the potential therapeutic synergies achieved by combining these agents with immune checkpoint inhibitors.

Identification of Cytochrome P450 2E1 as a Novel Target in Glioma and Development of Its Inhibitor as an Anti-Tumor Agent

Glioblastoma (GBM) is a devastating inflammation-related cancer for which novel therapeutic targets are urgently required. Previous studies of the authors indicate Cytochrome P450 2E1 (CYP2E1) as a novel inflammatory target and develop a specific inhibitor Q11. Here it is demonstrated that CYP2E1 overexpression is closely related to higher malignancy in GBM patients. CYP2E1 activity is positively correlated with tumor weight in GBM rats. Significantly higher CYP2E1 expression accompanied by increased inflammation is detected in a mouse GBM model. Q11, 1-(4-methyl-5-thialzolyl) ethenone, a newly developed specific inhibitor of CYP2E1 here remarkably attenuates tumor growth and prolongs survival in vivo. Q11 does not directly affect tumor cells but blocks the tumor-promoting effect of microglia/macrophage (M/Mφ) in the tumor microenvironment through PPARγ-mediated activation of the STAT-1 and NF-κB pathways and inhibition of the STAT-3 and STAT-6 pathways. The effectiveness and safety of targeting CYP2E1 in GBM are further supported by studies with Cyp2e1 knockout rodents. In conclusion, a pro-GBM mechanism in which CYP2E1-PPARγ-STAT-1/NF-κB/STAT-3/STAT-6 axis fueled tumorigenesis by reprogramming M/Mφ and Q11 as a promising anti-inflammatory agent for GBM treatment is uncovered.

Sex-dependent PD-L1/sPD-L1 trafficking in human endothelial cells in response to inflammatory cytokines and VEGF

Programmed cell death 1 ligand 1 (PD-L1) expressed in non-immune cells is involved in immune-mediated tissue damage in the context of inflammatory conditions and tumor immune escape. Emerging evidence suggests soluble (s)PD-L1 as a marker of inflammation. Based on well-established sex-specific differences in immunity, we tested the novel hypotheses that (i) endothelial cell PD-L1 is modulated by inflammatory cytokines and vascular endothelial growth factor (VEGF) in a sex-specific fashion, and (ii) the endothelium is a source of sPD-L1. After exposure of human umbilical vein endothelial cells (HUVECs) to lipopolysaccharide, interleukin (IL)1β or VEGF for 24 h, total PD-L1 levels were upregulated solely in cells from female donors, while being unchanged in those from male donors. Accordingly, exposure to synovial fluids from patients with inflammatory arthritis upregulated PD-L1 levels in HUVECs from female donors only. Membrane PD-L1 expression as measured by flow cytometry was unchanged in response to inflammatory stimuli. However, exposure to 2 ng/mL IL-1β or 50 ng/mL VEGF time-dependently increased sPD-L1 release by HUVECs from female donors. Treatment with the metalloproteinase (MMP) inhibitor GM6001 (10 μM) prevented IL-1β-induced sPD-L1 release and enhanced membrane PD-L1 levels. The anti-VEGF agents bevacizumab and sunitinib reduced both VEGF-induced PD-L1 accumulation and sPD-L1 secretion. Thus, inflammatory agents and VEGF rapidly increased endothelial PD-L1 levels in a sex-specific fashion. Furthermore, the vascular endothelium may be a sPD-L1 source, whose production is MMP-dependent and modulated by anti-VEGF agents. These findings may have implications for sex-specific immunity, vascular inflammation and response to anti-angiogenic therapy.

PD-1/PD-L1 checkpoint inhibitors in advanced hepatocellular carcinoma immunotherapy

Hepatocellular carcinoma (HCC) has a high prevalence and mortality rate worldwide. Sorafenib monotherapy has been the standard of first-line treatment for advanced HCC for a long time, but there are still many shortcomings. In recent years, with the deepening of research on tumor immune microenvironment, researchers have begun to explore new approaches in immunotherapy, and the introduction of immune checkpoint inhibitors has brought fundamental changes to the treatment of HCC. Programmed cell death protein 1 (PD-1) is an immune checkpoint molecule that plays an important role in down-regulating immune system function and promoting tolerance. Programmed cell death ligand 1 (PDL-1) is involved in tumor immune evasion by binding to PD-1, resulting in failure of treatment. Currently, immunotherapy targeting the PD-1/PD-L1 axis has achieved unprecedented success in HCC, but it also faces great challenges, with its low remission rate still to be solved. For most patients with HCC, the PD-1/PD-L1 pathway is not the only rate limiting factor of antitumor immunity, and blocking only the PD-1/PD-L1 axis is not enough to stimulate an effective antitumor immune response; thus, combination therapy may be a better option. In this study, changes in the immune microenvironment of HCC patients were reviewed to clarify the feasibility of anti-PD-1/PD-L1 therapy, and a series of monotherapy and combination therapy clinical trials were summarized to verify the safety and efficacy of this newly developed treatment in patients with advanced HCC. Furthermore, we focused on hyperprogressive disease and drug resistance to gain a better understanding of PD-1/PD-L1 blockade as a promising treatment.

Metabolic regulation of immune responses to cancer

The tumor microenvironment is an ecosystem composed of multiple types of cells, such as tumor cells, immune cells, and cancer-associated fibroblasts. Cancer cells grow faster than non-cancerous cells and consume larger amounts of nutrients. The rapid growth characteristic of cancer cells fundamentally alters nutrient availability in the tumor microenvironment and results in reprogramming of immune cell metabolic pathways. Accumulating evidence suggests that cellular metabolism of nutrients, such as lipids and amino acids, beyond being essential to meet the bioenergetic and biosynthetic demands of immune cells, also regulates a broad spectrum of cellular signal transduction, and influences immune cell survival, differentiation, and anti-tumor effector function. The cancer immunometabolism research field is rapidly evolving, and exciting new discoveries are reported in high-profile journals nearly weekly. Therefore, all new findings in this field cannot be summarized within this short review. Instead, this review is intended to provide a brief introduction to this rapidly developing research field, with a focus on the metabolism of two classes of important nutrients-lipids and amino acids-in immune cells. We highlight recent research on the roles of lipids and amino acids in regulating the metabolic fitness and immunological functions of T cells, macrophages, and natural killer cells in the tumor microenvironment. Furthermore, we discuss the possibility of "editing" metabolic pathways in immune cells to act synergistically with currently available immunotherapies in enhancing anti-tumor immune responses.

Inhibition of DNMT1 potentiates antitumor immunity in oral squamous cell carcinoma

Epigenetic alterations, including DNA methylation, play crucial roles in the tumor. Epigenetic drugs like DNA methyltransferase-1 (DNMT1) inhibitors have been exhibited positive effects in cancer treatment. However, the role of DNMT1 in oral squamous cell carcinoma (OSCC) is less clearly described. What is more, the effects on the immune microenvironment of DNMT1 have not become appreciated. In this research, we determine the expression levels of DNMT1 and the association of prognosis by analyzing human OSCC tissue microarrays. Two different types of immunocompetent mouse OSCC models were established to explore the effects of DNMT1 inhibitor on the tumor microenvironment(TME). We identified DNMT1 was highly expressed both in human and mouse OSCC tissues. The expression levels of DNMT1 was also correlated with the immunosuppressive molecules and tumor-promoter such as VISTA, PD-L1, B7-H4, and PAK2, indicating a worse prognosis. Of particular concern is that DNMT1 inhibition improved TME and delayed tumor growth by decreasing myeloid-derived suppressor cells (MDSCs) and increasing tumor-infiltrating T cells. Our data suggests that DNMT1 play a key role in OSCC and has a possible immunotherapeutic marker treatment.

Oral reactive capillary hemangiomas induced by SHR-1210 in the treatment of non-small cell lung cancer: a case report and literature review

BACKGROUND

Antibodies to PD-1 and PD-L1 have remarkably improved the overall survival of many patients with advanced solid tumors. SHR-1210 is an anti-PD-1 monoclonal antibody. Dermatologic reactive capillary hemangiomas (RCH) were the most common and unique drug-related AEs of SHR-1210, but rare on oral mucosa and gastrointestinal mucosa. Herein we report a case of RCH occurred in oral mucosa during the clinical trials of SHR-1210 in the treatment of non-small cell lung cancer.

CASE PRESENTATION

A male in his 60 s with a history of non-small cell lung cancer received injection of anti-PD-1 monoclonal antibodies SHR-1210. The patient developed drug-related RCH on skin after the first injection and began to have gingival hyperplasia one year after the first injection which gradually increased in size and affect eating and speaking. Anti-PD-1 treatments were continued. After periodontal treatment, two oral lesions and one skin lesion were surgically removed. Similar histological manifestation was found in all three lesions as reactive capillary hemangiomas. All lesions had a good prognosis without recurrence on oral mucosa within one year after surgery.

CONCLUSIONS

Oral reactive capillary hemangiomas could be induced by SHR-1210 in the treatment of non-small cell lung cancer. Surgical resection is an effective treatment with a good prognosis.

Identification of Notch signaling pathway gene mutations as a prognostic biomarker for bladder cancer

Purpose: The authors aimed to identify Notch signaling pathway gene mutations as a prognostic biomarker for bladder cancer. Methods: First, critical Notch signaling pathway genes were screened using The Cancer Genome Atlas and validation sets. Second, immune infiltration, protein-protein interaction network, Kyoto Encyclopedia of Genes and Genomes and Gene Set Enrichment Analysis analyses were performed. Finally, potential immunotherapy drug targets were screened using T-cell receptors, B-cell receptors and CERES scores for bladder cancer. Results: The NOTCH7 gene was identified, with a significant difference in immune infiltration level between mutant and wild type in bladder cancer, mainly related to T cells. NOTCH7 was an immunotherapy prognostic factor, and IRF1 and B2M were the potential drug targets for NOTCH7 mutation in bladder cancer. Conclusion: NOTCH7 gene mutation can be used as an immunotherapy biomarker for bladder cancer.