Structure of PD1 and its mechanism in the treatment of autoimmune diseases

PD-1/PD-L1 axis: implications in immune regulation, cancer progression, and translational applications

The PD-1/PD-L1 axis is a complex signaling pathway that has an important role in the immune system cells. Programmed cell death protein 1 (PD-1) acts as an immune checkpoint on the T lymphocytes, B lymphocytes, natural killer (NK), macrophages, dendritic cells (DCs), monocytes, and myeloid cells. Its ligand, the programmed cell death 1 ligand (PD-L1), is expressed in the surface of the antigen-presenting cells (APCs). The binding of both promotes the downregulation of the T cell response to ensure the activation to prevent the onset of chronic immune inflammation. This axis in the tumor microenvironment (TME) performs a crucial role in the tumor progression and the escape of the tumor by neutralizing the immune system, the engagement of PD-L1 with PD-1 in the T cell causes dysfunctions, neutralization, and exhaustion, providing the tumor mass production. This review will provide a comprehensive overview of the functions of the PD-1/PD-L1 system in immune function, cancer, and the potential therapeutic implications of the PD-1/PD-L1 pathway for cancer management.

Unveiling the promise of PD1/PD-L1: A new dawn in immunotherapy for cholangiocarcinoma

Cholangiocarcinoma (CCA), a rare yet notably aggressive cancer, has experienced a surge in incidence in recent years. Presently, surgical resection remains the most effective curative strategy for CCA. Nevertheless, a majority of patients with CCA are ineligible for surgical removal at the time of diagnosis. For advanced stages of CCA, the combination of gemcitabine and cisplatin is established as the standard chemotherapy regimen. Despite this, treatment efficacy is often hindered by the development of resistance. In recent times, immune checkpoint inhibitors, particularly those that block programmed death 1 and its ligand (PD1/PD-L1), have emerged as promising strategies against a variety of cancers and are being increasingly integrated into the therapeutic landscape of CCA. A growing body of research supports that the use of PD1/PD-L1 monoclonal antibodies in conjunction with chemotherapy may significantly improve patient outcomes. This article seeks to meticulously review the latest studies on PD1/PD-L1 involvement in CCA, delving into their expression profiles, prognostic significance, contribution to oncogenic processes, and their potential clinical utility.

Exosome-mediated communication between gastric cancer cells and macrophages: implications for tumor microenvironment

Gastric cancer (GC) is a malignant neoplasm originating from the epithelial cells of the gastric mucosa. The pathogenesis of GC is intricately linked to the tumor microenvironment within which the cancer cells reside. Tumor-associated macrophages (TAMs) primarily differentiate from peripheral blood monocytes and can be broadly categorized into M1 and M2 subtypes. M2-type TAMs have been shown to promote tumor growth, tissue remodeling, and angiogenesis. Furthermore, they can actively suppress acquired immunity, leading to a poorer prognosis and reduced tolerance to chemotherapy. Exosomes, which contain a myriad of biologically active molecules including lipids, proteins, mRNA, and noncoding RNAs, have emerged as key mediators of communication between tumor cells and TAMs. The exchange of these molecules via exosomes can markedly influence the tumor microenvironment and consequently impact tumor progression. Recent studies have elucidated a correlation between TAMs and various clinicopathological parameters of GC, such as tumor size, differentiation, infiltration depth, lymph node metastasis, and TNM staging, highlighting the pivotal role of TAMs in GC development and metastasis. In this review, we aim to comprehensively examine the bidirectional communication between GC cells and TAMs, the implications of alterations in the tumor microenvironment on immune escape, invasion, and metastasis in GC, targeted therapeutic approaches for GC, and the efficacy of potential GC drug resistance strategies.

Amplifying T cell-mediated antitumor immune responses in nonsmall cell lung cancer through photodynamic therapy and anti-PD1

Photodynamic therapy (PDT) is nowadays widely employed in cancer treatment. We sought to assess the efficacy of combining PDT with anti-programmed cell death protein 1 (PD1) and to investigate the associated mechanisms in nonsmall cell lung cancer (NSCLC). We established a xenograft tumor model in C57BL/6J mice using Lewis lung carcinoma (LLC) cells, recorded tumor growth, and quantified reactive oxygen species (ROS) levels using a ROS detection kit. Pathological changes were assessed through H&E staining, while immunofluorescence (IF) was used to determine the expression of CD8 and Foxp3. Transcriptomic analysis was conducted, analyzing differential expressed genes (DEGs) among control, PDT, and PDT combined with anti-PD1 (PDT+anti-PD1) groups. Functional enrichment analysis via Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) was performed. The Cancer Genome Atlas (TCGA) database was utilized to analyze the expression of aminolevulinate synthase gene (ALAS2), integrin alpha10 (ITGA10), ATP1A2, a disintegrin and metalloprotease 12 (ADAM12), and Lox1 in lung adenocarcinoma and adjacent tissues, with concurrent immune infiltration analysis. Quantitative real-time polymerase chain reaction and western blot were employed to measure mRNA and protein expression levels. Treatment with PDT combined with anti-PD1 significantly inhibited tumor growth and increased the number of CD8+ cells while decreasing Foxp3+ cells. Immune infiltration results presented ALAS2, ADAM12, and ITGA10 were associated with various types of T cells or macrophages. Additionally, the expression levels of EGFR, ERK, and PI3K/Akt were suppressed after PDT with anti-PD1 treatment. Our findings collectively suggest that PDT combined with anti-PD1 treatment could enhance the infiltration of CD8+ T cells, suppressing tumor growth, and this effect was associated with ALAS2, ITGA10, and ADAM12. The underlying mechanism might be linked to EGFR, ERK, and PI3K/Akt signaling. Overall, this study provides valuable insights into the application of PDT combined with anti-PD1 treatment in NSCLC.