Regulation of PD-L1: a novel role of pro-survival signalling in cancer

Lycorine inhibits Ang II-induced heart remodeling and inflammation by suppressing the PI3K-AKT/NF-κB pathway

BACKGROUND

Ang II induces hypertensive heart failure (HF) via hemodynamic and non-hemodynamic actions. Lycorine (LYC) is an alkaloid derived from Lycoris bulbs, and it possesses anti-cardiovascular disease-related activities. Herein, we explored the potential LYC-mediated regulation of Ang II-induced HF.

METHODS

Over 4 weeks, we established a hypertensive HF mouse model by infusing Ang II into C57BL/6 mice using a micro-osmotic pump. For the final two weeks, mice were administered LYC via intraperitoneal injection. The LYC signaling network was then deduced using RNA sequencing.

RESULTS

LYC administration strongly suppressed hypertrophy, myocardial fibrosis, and cardiac inflammation. As a result, it minimized heart dysfunction while causing no changes in blood pressure. The Nuclear Factor kappa B (NF-κB) network/phosphoinositol-3-kinase (PI3K)-protein kinase B (AKT) was found to be a major modulator of LYC-based cardioprotection using RNA sequencing study. We further confirmed that in cultured cardiomyocytes and mouse hearts, LYC reduced the inflammatory response and downregulated the Ang II-induced PI3K-AKT/NF-κB network. Moreover, PI3K-AKT or NF-κB axis depletion in cardiomyocytes completely abrogated the anti-inflammatory activities of LYC.

CONCLUSION

Herein, we demonstrated that LYC safeguarded hearts in Ang II -stimulated mice by suppressing the PI3K-AKT/NF-κB-induced inflammatory responses. Given the evidence mentioned above, LYC is a robust therapeutic agent for hypertensive HF.

Neopterin as a potential prognostic and predictive biomarker in metastatic renal cell carcinoma treated with immune checkpoint inhibitors

INTRODUCTION

Immunotherapy represents a significant and essential component of renal carcinoma therapy (RCC), but the selection of an optimal regimen for an individual patient remains unclear. Despite significant improvements in therapeutic options for RCC, predictive biomarkers for immunotherapeutic agents remain elusive. Neopterin is a biomarker of cell-mediated immune response, with concentrations increased in different disorders, including cancer. High neopterin levels herald, in general, a poor prognosis.

AREAS COVERED

This review briefly overviews the contemporary clinical data on biomarkers in metastatic RCC therapy, focusing on neopterin.

EXPERT OPINION

Elevated neopterin levels have been observed in tumors of different primary locations. Research indicates that neopterin may serve as a potential biomarker for assessing the inflammatory status associated with certain cancers. However, it is necessary to interpret neopterin levels in the context of a comprehensive clinical evaluation, as elevated neopterin alone is not specific to cancer and can be influenced by other factors, including comorbid conditions. Neopterin has also been identified as a prognostic biomarker. An increasing neopterin level in serum and urine is associated with advanced cancer, but the role as a potential predictor of response to immunotherapy has yet to be established. A reliable biomarker for optimal therapy selection in metastatic RCC is still putative.

Critical role of the gut microbiota in immune responses and cancer immunotherapy

The gut microbiota plays a critical role in the progression of human diseases, especially cancer. In recent decades, there has been accumulating evidence of the connections between the gut microbiota and cancer immunotherapy. Therefore, understanding the functional role of the gut microbiota in regulating immune responses to cancer immunotherapy is crucial for developing precision medicine. In this review, we extract insights from state-of-the-art research to decipher the complicated crosstalk among the gut microbiota, the systemic immune system, and immunotherapy in the context of cancer. Additionally, as the gut microbiota can account for immune-related adverse events, we discuss potential interventions to minimize these adverse effects and discuss the clinical application of five microbiota-targeted strategies that precisely increase the efficacy of cancer immunotherapy. Finally, as the gut microbiota holds promising potential as a target for precision cancer immunotherapeutics, we summarize current challenges and provide a general outlook on future directions in this field.

Enhancing cancer immunotherapy: Exploring strategies to target the PD-1/PD-L1 axis and analyzing the associated patent, regulatory, and clinical trial landscape

Cancer treatment modalities and their progression is guided by the specifics of cancer, including its type and site of localization. Surgery, radiation, and chemotherapy are the most often used conventional treatments. Conversely, emerging treatment techniques include immunotherapy, hormone therapy, anti-angiogenic therapy, dendritic cell-based immunotherapy, and stem cell therapy. Immune checkpoint inhibitors' anticancer properties have drawn considerable attention in recent studies in the cancer research domain. Programmed Cell Death Protein-1 (PD-1) and its ligand (PD-L1) checkpoint pathway are key regulators of the interactions between activated T-cells and cancer cells, protecting the latter from immune destruction. When the ligand PD-L1 attaches to the receptor PD-1, T-cells are prevented from destroying cells that contain PD-L1, including cancer cells. The PD-1/PD-L1 checkpoint inhibitors block them, boosting the immune response and strengthening the body's defenses against tumors. Recent years have seen incredible progress and tremendous advancement in developing anticancer therapies using PD-1/PD-L1 targeting antibodies. While immune-related adverse effects and low response rates significantly limit these therapies, there is a need for research on methods that raise their efficacy and lower their toxicity. This review discusses various recent innovative nanomedicine strategies such as PLGA nanoparticles, carbon nanotubes and drug loaded liposomes to treat cancer targeting PD-1/PD-L1 axis. The biological implications of PD-1/PD-L1 in cancer treatment and the fundamentals of nanotechnology, focusing on the novel strategies used in nanomedicine, are widely discussed along with the corresponding guidelines, clinical trial status, and the patent landscape of such formulations.

Machine learning-based integration develops a stress response stated T cell (Tstr)-related score for predicting outcomes in clear cell renal cell carcinoma

BACKGROUND

Establishment of a reliable prognostic model and identification of novel biomarkers are urgently needed to develop precise therapy strategies for clear cell renal cell carcinoma (ccRCC). Stress response stated T cells (Tstr) are a new T-cell subtype, which are related to poor disease stage and immunotherapy response in various cancers.

METHODS

10 machine-learning algorithms and their combinations were applied in this work. A stable Tstr-related score (TCs) was constructed to predict the outcomes and PD-1 blockade treatment response in ccRCC patients. A nomogram based on TCs for personalized prediction of patient prognosis was constructed. Functional enrichment analysis and TimiGP algorithm were used to explore the underlying role of Tstr in ccRCC. The key TCs-related gene was identified by comprehensive analysis, and the bioinformatics results were verified by immunohistochemistry using a tissue microarray.

RESULTS

A robust TCs was constructed and validated in four independent cohorts. TCs accurately predicted the prognosis and PD-1 blockade treatment response in ccRCC patients. The novel nomogram was able to precisely predict the outcomes of ccRCC patients. The underlying biological process of Tstr was related to acute inflammatory response and acute-phase response. Mast cells were identified to be involved in the role of Tstr as a protective factor in ccRCC. TNFS13B was shown to be the key TCs-related gene, which was an independent predictor of unfavorable prognosis. The protein expression analysis of TNFSF13B was consistent with the mRNA analysis results. High expression of TNFSF13B was associated with poor response to PD-1 blockade treatment.

CONCLUSIONS

This study provides a Tstr cell-related score for predicting outcomes and PD-1 blockade therapy response in ccRCC. Tstr cells may exert their pro-tumoral role in ccRCC, acting against mast cells, in the acute inflammatory tumor microenvironment. TNFSF13B could serve as a key biomarker related to TCs.

Pan-Cancer Proteomics Analysis Reveals Wiskott-Aldrich Syndrome Protein as a Potential Regulator of Programmed Death-Ligand 1

The programmed death-ligand 1 (PD-L1) is a key mediator of immunosuppression in the tumor microenvironment. The expression of PD-L1 in cancer cells is useful for the clinical determination of an immune checkpoint blockade (ICB). However, the regulatory mechanism of the PD-L1 abundance remains incompletely understood. Here, we integrated the proteomics of 52 patients with solid tumors and examined immune cell infiltration to reveal PD-L1-related regulatory modules. Wiskott-Aldrich syndrome protein (WASP) was identified as a potential regulator of PD-L1 transcription. In two independent cohorts containing 164 cancer patients, WASP expression was significantly associated with PD-L1. High WASP expression contributed to immunosuppressive cell composition, including cells positive for immune checkpoints (PD1, CTLA4, TIGIT, and TIM3), FoxP3+ Treg cells, and CD163+ tumor-associated macrophages. Overexpression of WASP increased, whereas knockdown of WASP decreased the protein level of PD-L1 in cancer cells without alteration of PD-L1 protein stability. The WASP-mediated cell migration and invasion were markedly attenuated by the silence of PD-L1. Collectively, our data suggest that WASP is a potential regulator of PD-L1 and the WASP/PD-L1 axis is responsible for cell migration and an immunosuppressive microenvironment.

Exercise accelerates recruitment of CD8+ T cell to promotes anti-tumor immunity in lung cancer via epinephrine

BACKGROUND AND PURPOSE

In recent years, there has been extensive research on the role of exercise as an adjunctive therapy for cancer. However, the potential mechanisms underlying the anti-tumor therapy of exercise in lung cancer remain to be fully elucidated. As such, our study aims to confirm whether exercise-induced elevation of epinephrine can accelerate CD8+ T cell recruitment through modulation of chemokines and thus ultimately inhibit tumor progression.

METHOD

C57BL/6 mice were subcutaneously inoculated with Lewis lung cancer cells (LLCs) to establish a subcutaneous tumor model. The tumor mice were randomly divided into different groups to performed a moderate-intensity exercise program on a treadmill for 5 consecutive days a week, 45 min a day. The blood samples and tumor tissues were collected after exercise for IHC, RT-qPCR, ELISA and Western blot. In addition, another group of mice received daily epinephrine treatment for two weeks (0.05 mg/mL, 200 µL i.p.) (EPI, n = 8) to replicate the effects of exercise on tumors in vivo. Lewis lung cancer cells were treated with different concentrations of epinephrine (0, 5, 10, 20 µM) to detect the effect of epinephrine on chemokine levels via ELISA and RT-qPCR.

RESULTS

This study reveals that both pre- and post-cancer exercise effectively impede the tumor progression. Exercise led to an increase in EPI levels and the infiltration of CD8+ T cell into the lung tumor. Exercise-induced elevation of EPI is involved in the regulation of Ccl5 and Cxcl10 levels further leading to enhanced CD8+ T cell infiltration and ultimately inhibiting tumor progression.

CONCLUSION

Exercise training enhance the anti-tumor immunity of lung cancer individuals. These findings will provide valuable insights for the future application of exercise therapy in clinical practice.

Modification of the tumor microenvironment enhances immunity with plasmid gene therapy

Local intratumor delivery with electroporation of low levels of plasmids encoding molecules, induces an antitumor effect without causing systemic toxicity. However, previous studies have predominately focused on the function of the delivered molecule encoded within the plasmid, and ignored the plasmid vector. In this study, we found vectors pUMVC3 and pVax1 induced upregulation of MHC class I (MHC-I) and PD-L1 on tumor cell surface. These molecules participate in a considerable number of immunoregulatory functions through their interactions with and activating inhibitory immune cell receptors. MHC molecules are well-known for their role in antigen (cross-) presentation, thereby functioning as key players in the communication between immune cells and tumor cells. Increased PD-L1 expression on tumor cells is an important monitor of tumor growth and the effectiveness of immune inhibitor therapy. Results from flow cytometry confirmed increased expression of MHC-I and PDL-1 on B16F10, 4T1, and KPC tumor cell lines. Preliminary animal data from tumor-bearing models, B16F10 melanoma, 4T1 breast cancer and KPC pancreatic cancer mouse models showed that tumor growth was attenuated after pUMVC3 intratumoral electroporation. Our data also documented that pSTAT1 signaling pathway might not be associated with plasmid vectors' function of upregulating MHC-I, PD-L1 on tumor cells.

Established and emerging biomarkers of immunotherapy in renal cell carcinoma

Immunotherapies, such as immune checkpoint inhibitors, have heralded impressive progress for patient care in renal cell carcinoma (RCC). Despite this success, some patients' disease fails to respond, and other patients experience significant side effects. Thus, development of biomarkers is needed to ensure that patients can be selected to maximize benefit from immunotherapies. Improving clinicians' ability to predict which patients will respond to immunotherapy and which are most at risk of adverse events - namely through clinical biomarkers - is indispensable for patient safety and therapeutic efficacy. Accordingly, an evolving suite of therapeutic biomarkers continues to be investigated. This review discusses biomarkers for immunotherapy in RCC, highlighting current practices and emerging innovations, aiming to contribute to improved outcomes for patients with RCC.

Computational analysis of PD-L1 dimerization mechanism induced by small molecules and potential dynamical properties

The design of small molecule inhibitors that target the programmed death ligand-1 (PD-L1) is a forefront issue in immune checkpoint blocking therapy. Small-molecule inhibitors have been shown to exert therapeutic effects by inducing dimerization of the PD-L1 protein, however, the specific mechanisms underlying this dimerization process remain largely unexplored. Furthermore, there is a notable lack of comparative studies examining the binding modes of structurally diverse inhibitors. In view of the research gaps, this work employed molecular dynamics simulations to meticulously examine the interactions between two distinct types of inhibitors and PD-L1 in both monomeric and dimeric forms, and predicted the dimerization mechanism. The results revealed that inhibitors initially bind to a PD-L1 monomer, subsequently attracting another monomer to form a dimer. Notably, symmetric inhibitors observed superior binding efficiency compared to other inhibitors. Key residues, including Ile54, Tyr56, Met115 and Tyr123 played a leading role in binding. Structurally, symmetric inhibitors were capable of thoroughly engaging the binding pocket, promoting a more symmetrical formation of PD-L1 dimers. Furthermore, symmetric inhibitors formed more extensive hydrophobic interactions with protein residues. The insights garnered from this research are expected to significantly contribute to the rational design and optimization of small molecule inhibitors targeting PD-L1.

Exosomes promote pre-metastatic niche formation in colorectal cancer

It is well known that colorectal cancer (CRC) has a high morbidity rate, a poor prognosis when metastasized, and a greatly shortened 5-year survival rate. Therefore, understanding the mechanism of tumor metastasis is still important. Based on the "seed and soil" theory, the concept of " premetastatic niche (PMN)" was introduced by Kaplan et al. The complex interaction between primary tumors and the metastatic organ provides a beneficial microenvironment for tumor cells to colonize at a distance. With further exploration of the PMN, exosomes have gradually attracted interest from researchers. Exosomes are extracellular vesicles secreted from cells that include various biological information and are involved in communication between cells. As a key molecule in the PMN, exosomes are closely related to tumor metastasis. In this article, we obtained information by conducting a comprehensive search across academic databases including PubMed and Web of Science using relevant keywords. Only recent, peer-reviewed articles published in the English language were considered for inclusion. This study aims to explore in depth how exosomes promote the formation of pre-metastatic microenvironment (PMN) in colorectal cancer and its related mechanisms.

A self-assembly active nanomodulator based on berberine for photothermal immunotherapy of breast cancer via dual regulation of immune suppression

Breast cancer (BC) remains a significant global health concern, especially affecting women, necessitating the development of effective treatment strategies. Photothermal immunotherapy has holds promise for addressing BC by eradicating tumors, preventing metastasis, and reducing recurrence rates. However, the dynamic amplification of indoleamine 2,3-dioxygenase 1 (IDO-1) and programmed cell death-ligand 1 (PD-L1) triggered by photothermal therapy (PTT) poses presents a significant barrier to immune cell infiltration, thus promoting immune evasion. To enhance overall efficiency, a hyaluronic acid (HA)-coated berberine (BBR)-indocyanine green self-assembly active nano modulator (HBI NDs) was successfully developed. This nano modulator aims to reverse immune resistance and further contribute to the synergistic anti-tumor effects. The prepared HBI NDs demonstrated a uniform spherical morphology, high drug loading, and favorable optical properties. The results based on in vitro cell experiments and tumor animal models confirmed that HBI NDs selectively accumulated in tumor tissues, downregulated PD-L1 and IDO-1 protein expression, and induced elevated cell apoptosis. Consequently, these effects result in efficient immune infiltration and positive anti-tumor outcomes. In conclusion, the HBI NDs nanodrug exhibits considerable potential as a novel agent for enhancing anticancer efficacy and promoting immune infiltration.

Neoadjuvant chemo-immunotherapy with camrelizumab plus nab-paclitaxel and cisplatin in resectable locally advanced squamous cell carcinoma of the head and neck: a pilot phase II trial

Neoadjuvant chemoimmunotherapy has emerged as a potential treatment option for resectable head and neck squamous cell carcinoma (HNSCC). In this single-arm phase II trial (NCT04826679), patients with resectable locally advanced HNSCC (T2‒T4, N0‒N3b, M0) received neoadjuvant chemoimmunotherapy with camrelizumab (200 mg), nab-paclitaxel (260 mg/m2), and cisplatin (60 mg/m2) intravenously on day one of each three-week cycle for three cycles. The primary endpoint was the objective response rate (ORR). Secondary endpoints included pathologic complete response (pCR), major pathologic response (MPR), two-year progression-free survival rate, two-year overall survival rate, and toxicities. Here, we report the perioperative outcomes; survival outcomes were not mature at the time of data analysis. Between April 19, 2021 and March 17, 2022, 48 patients were enrolled and received neoadjuvant therapy, 27 of whom proceeded to surgical resection and remaining 21 received non-surgical therapy. The ORR was 89.6% (95% CI: 80.9, 98.2) among 48 patients who completed neoadjuvant therapy. Of the 27 patients who underwent surgery, 17 (63.0%, 95% CI: 44.7, 81.2) achieved a MPR or pCR, with a pCR rate of 55.6% (95% CI: 36.8, 74.3). Treatment-related adverse events of grade 3 or 4 occurred in two patients. This study meets the primary endpoint showing potential efficacy of neoadjuvant camrelizumab plus nab-paclitaxel and cisplatin, with an acceptable safety profile, in patients with resectable locally advanced HNSCC.

MicroRNA-561-3p indirectly regulates the PD-L1 expression by targeting ZEB1, HIF1A, and MYC genes in breast cancer

Globally, breast cancer is the second most common cause of cancer-related deaths among women. In breast cancer, microRNAs (miRNAs) are essential for both the initiation and development of tumors. It has been suggested that the tumor suppressor microRNA-561-3p (miR-561-3p) is crucial in arresting the growth of cancer cells. Further research is necessary to fully understand the role and molecular mechanism of miR-561 in human BC. The aim of this study was to investigate the inhibitory effect of miR-561-3p on ZEB1, HIF1A, and MYC expression as oncogenes that have the most impact on PD-L1 overexpression and cellular processes such as proliferation, apoptosis, and cell cycle in breast cancer (BC) cell lines. The expression of ZEB1, HIF1A, and MYC genes and miR-561-3p were measured in BC clinical samples and cell lines via qRT-PCR. The luciferase assay, MTT, Annexin-PI staining, and cell cycle experiments were used to assess the effect of miR-561-3p on candidate gene expression, proliferation, apoptosis, and cell cycle progression. Flow cytometry was used to investigate the effects of miR-561 on PD-L1 suppression in the BC cell line. The luciferase assay showed that miRNA-561-3p targets the 3'-UTRs of ZEB1, HIF1A and MYC genes significantly. In BC tissues, the qRT-PCR results demonstrated that miR-561-3p expression was downregulated and the expression of ZEB1, HIF1A and MYC genes was up-regulated. It was shown that overexpression of miR-561-3p decreased PD-L1 expression and BC cell proliferation, and induced apoptosis and cell cycle arrest through downregulation of candidate oncogenes. Furthermore, inhibition of candidate genes by miR-561-3p reduced PD-L1 at both mRNA and protein levels. Our research investigated the impact of miR-561-3p on the expression of ZEB1, HIF1A and MYC in breast cancer cells for the first time. Our findings may help clarify the role of miR-561-3p in PD-L1 regulation and point to this miR as a potential biomarker and novel therapeutic target for cancer immunotherapy.

Benzosceptrin C induces lysosomal degradation of PD-L1 and promotes antitumor immunity by targeting DHHC3

Programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) blockade has become a mainstay of cancer immunotherapy. Targeting the PD-1/PD-L1 axis with small molecules is an attractive approach to enhance antitumor immunity. Here, we identified a natural marine product, benzosceptrin C (BC), that enhances the cytotoxicity of T cells to cancer cells by reducing the abundance of PD-L1. Furthermore, BC exerts its antitumor effect in mice bearing MC38 tumors by activating tumor-infiltrating T cell immunity. Mechanistic studies suggest that BC can prevent palmitoylation of PD-L1 by inhibiting DHHC3 enzymatic activity. Subsequently, PD-L1 is transferred from the membrane to the cytoplasm and cannot return to the membrane via recycling endosomes, triggering lysosome-mediated degradation of PD-L1. Moreover, the combination of BC and anti-CTLA4 effectively enhances antitumor T cell immunity. Our findings reveal a previously unrecognized antitumor mechanism of BC and represent an alternative immune checkpoint blockade (ICB) therapeutic strategy to enhance the efficacy of cancer immunotherapy.

NSCLC: from tumorigenesis, immune checkpoint misuse to current and future targeted therapy

Non-small cell lung cancer (NSCLC) is largely promoted by a multistep tumorigenesis process involving various genetic and epigenetic alterations, which essentially contribute to the high incidence of mortality among patients with NSCLC. Clinical observations revealed that NSCLC also co-opts a multifaceted immune checkpoint dysregulation as an important driving factor in NSCLC progression and development. For example, a deregulated PI3K/AKT/mTOR pathway has been noticed in 50-70% of NSCLC cases, primarily modulated by mutations in key oncogenes such as ALK, EGFR, KRAS, and others. Additionally, genetic association studies containing patient-specific factors and local reimbursement criteria expose/reveal mutations in EGFR/ALK/ROS/BRAF/KRAS/PD-L1 proteins to determine the suitability of available immunotherapy or tyrosine kinase inhibitor therapy. Thus, the expression of such checkpoints on tumors and immune cells is pivotal in understanding the therapeutic efficacy and has been extensively studied for NSCLC treatments. Therefore, this review summarizes current knowledge in NSCLC tumorigenesis, focusing on its genetic and epigenetic intricacies, immune checkpoint dysregulation, and the evolving landscape of targeted therapies. In the context of current and future therapies, we emphasize the significance of antibodies targeting PD-1/PD-L1 and CTLA-4 interactions as the primary therapeutic strategy for immune system reactivation in NSCLC. Other approaches involving the promising potential of nanobodies, probodies, affibodies, and DARPINs targeting immune checkpoints are also described; these are under active research or clinical trials to mediate immune regulation and reduce cancer progression. This comprehensive review underscores the multifaceted nature, current state and future directions of NSCLC research and treatment.

Role of Epiregulin in Lung Tumorigenesis and Therapeutic Resistance

Epidermal growth factor (EGF) signaling regulates multiple cellular processes and plays an essential role in tumorigenesis. Epiregulin (EREG), a member of the EGF family, binds to the epidermal growth factor receptor (EGFR) and ErbB4, and it stimulates EGFR-related downstream pathways. Increasing evidence indicates that both the aberrant expression and oncogenic function of EREG play pivotal roles in tumor development in many human cancers, including non-small cell lung cancer (NSCLC). EREG overexpression is induced by activating mutations in the EGFR, KRAS, and BRAF and contributes to the aggressive phenotypes of NSCLC with oncogenic drivers. Recent studies have elucidated the roles of EREG in a tumor microenvironment, including the epithelial-mesenchymal transition, angiogenesis, immune evasion, and resistance to anticancer therapy. In this review, we summarized the current understanding of EREG as an oncogene and discussed its oncogenic role in lung tumorigenesis and therapeutic resistance.

CD47-a novel prognostic predicator in epithelial ovarian cancer and correlations with clinicopathological and gene mutation features

BACKGROUND

Epithelial ovarian cancer (EOC) is insensitive to immunotherapy due to its poor immunogenicity; thus, suitable biomarkers need to be identified for better prognostic stratification and individualized treatment. CD47 is a novel immunotherapy target; however, its impact on EOC prognosis is controversial and correlation with genetic features is unclear. The aim of this study was to investigate the prognostic significance of CD47 and its correlations with biological behaviors and genetic features of EOC.

METHODS

Immunohistochemistry (IHC) and next-generation sequencing (NGS) were performed to examine expressions of CD47, PD-L1, and genomic mutations in the tissue samples of 75 EOC patients. Various clinicopathologic and genomic features were then evaluated to determine their correlation with CD47 expression. Kaplan-Meier analysis and Cox regression analysis were used to identify independent prognostic factors. Risk score modeling was then established, and the predictive capacity of this model was further confirmed by nomogram analysis.

RESULTS

CD47 was mainly expressed in the tumor cell membrane and cytoplasm, and the rate of high CD47 expression was 63.7%. CD47 expression was associated with various clinicopathological factors, including FIGO stage, CA125 and HE4 value, presence of multidisciplinary surgeries, presence and volume of ascites, lymph-node metastasis, Ki-67 index and platinum-resistant, as well as genetic characteristics like BRCA mutation, HRD status, and TP53 mutation in EOC. Patients with high CD47 expression showed worse prognosis than the low-expression group. Cox regression analysis demonstrated that CA125, CD47, and BRCA mutation were independent factors for EOC prognosis. Patients were then categorized into high-risk and low-risk subgroups based on the risk score of the aforementioned independent factors, and the prognosis of the high-risk group was worse than those of the low-risk group. The nomogram showed adequate discrimination with a concordance index of 0.777 (95% CI, 0.732-0.822). The calibration curve showed good consistency.

CONCLUSION

CD47 correlated with various malignant biology and genetic characteristics of EOC and may play pivotal and multifaceted roles in the tumor microenvironment of EOC Finally, we constructed a reliable prediction model centered on CD47 and integrated CA125 and BRCA to better guide high-risk population management.

Connecting the mechanisms of tumor sex differences with cancer therapy

Sex differences in cancer incidence and survival are constant and pronounced globally, across all races and all age groups of cancer types. In 2016, after the National Institutes of Health proposed a policy of utilizing sex as a biological variable, researchers started paying more attention to the molecular mechanisms behind gender variations in cancer. Historically, most previous studies investigating sex differences have been centered on gonadal sex hormones. Nevertheless, sex differences also involve genetic and molecular pathways that run throughout the entire process of cancer cell proliferation, metastasis, and treatment response, in addition to sex hormones. In particular, there is significant gender dimorphism in the efficacy and toxicity of oncology treatments, including conventional radiotherapy and chemotherapy, as well as the emerging targeted therapies and immunotherapy. To be clear, not all mechanisms will exhibit gender bias, and not all gender bias will affect cancer risk. Our goal in this review is to discuss some of the significant sex-related changes in fundamental cancer pathways. To this purpose, we summarize the differential impact of gender on cancer development in three dimensions: sex hormones, genetics, and epigenetics, and focus on current hot subjects including tumor suppressor function, immunology, stem cell renewal, and non-coding RNAs. Clarifying the essential mechanisms of gender differences will help guide the clinical treatment of both sexes in tumor radiation and chemotherapy, medication therapy with various targets, immunotherapy, and even drug development. We anticipate that sex-differentiated research will help advance sex-based cancer personalized medicine models and encourage future basic scientific and clinical research to take sex into account.

Subcellular localization of PD-L1 and cell-cycle-dependent expression of nuclear PD-L1 variants: implications for head and neck cancer cell functions and therapeutic efficacy

The programmed cell death 1 ligand 1 (PD-L1)/programmed cell death protein 1 (PD-1) axis is primarily associated with immunosuppression in cytotoxic T lymphocytes (CTLs). However, mounting evidence is supporting the thesis that PD-L1 not only functions as a ligand but mediates additional cellular functions in tumor cells. Moreover, it has been demonstrated that PD-L1 is not exclusively localized at the cellular membrane. Subcellular fractionation revealed the presence of PD-L1 in various cellular compartments of six well-characterized head and neck cancer (HNC) cell lines, including the nucleus. Via Western blotting, we detected PD-L1 in its well-known glycosylated/deglycosylated state at 40-55 kDa. In addition, we detected previously unknown PD-L1 variants with a molecular weight at approximately 70 and > 150 kDa exclusively in nuclear protein fractions. These in vitro findings were confirmed with primary tumor samples from head and neck squamous cell carcinoma (HNSCC) patients. Furthermore, we demonstrated that nuclear PD-L1 variant expression is cell-cycle-dependent. Immunofluorescence staining of PD-L1 in different cell cycle phases of synchronized HNC cells supported these observations. Mechanisms of nuclear PD-L1 trafficking remain less understood; however, proximity ligation assays showed a cell-cycle-dependent interaction of the cytoskeletal protein vimentin with PD-L1, whereas vimentin could serve as a potential shuttle for nuclear PD-L1 transportation. Mass spectrometry after PD-L1 co-immunoprecipitation, followed by gene ontology analysis, indicated interaction of nuclear PD-L1 with proteins involved in DNA remodeling and messenger RNA (mRNA) splicing. Our results in HNC cells suggest a highly complex regulation of PD-L1 and multiple tumor cell-intrinsic functions, independent of immune regulation. These observations bear significant implications for the therapeutic efficacy of immune checkpoint inhibition.

The association of genomic alterations with PD-L1 expression in Chinese patients with EGFR/ALK wild-type lung adenocarcinoma and potential predictive value of Hippo pathway mutations to immunotherapy

BACKGROUND

The study focuses on PD-L1 expression as an essential biomarker for gauging the response of EGFR/ALK wild-type NSCLC patients to FDA-approved immune checkpoint inhibitors (ICIs). It aims to explore clinical, molecular, and immune microenvironment characteristics associated with PD-L1 expression in EGFR/ALK wild-type lung adenocarcinoma patients eligible for ICI therapy.

METHODS

In this retrospective study, tumor samples from 359 Chinese EGFR/ALK wild-type lung adenocarcinoma patients underwent comprehensive evaluations for PD-L1 expression and NGS-targeted sequencing. The investigation encompassed the analysis and comparison of clinical traits, gene mutations, pathways, and immune signatures between two groups categorized by PD-L1 status: negative (TPS < 1%) and positive (TPS ≥ 1%). Additionally, the study explored the link between genomic changes and outcomes following immunotherapy.

RESULTS

High tumor mutational burden correlated significantly with PD-L1 positivity in patients with EGFR/ALK wild-type lung adenocarcinoma. Gene alterations, including TP53, KRAS, and others, were more pronounced in the PD-L1 positive group. Pathway analysis highlighted higher frequencies of alterations in pathways like RTK/RAS, p53, and Hippo in PD-L1-positive patients. The Hippo pathway's relevance was confirmed in separate immunotherapy cohorts, associated with better outcomes. In terms of immune cell infiltration, Hippo mutants exhibited higher levels of CD68+ PD-L1+ macrophages, CD8+ T cells, and CD8+ PD-1- T cells.

CONCLUSIONS

This study offers insights into genomic features of Chinese EGFR/ALK wild-type lung adenocarcinoma patients based on PD-L1 expression. Notably, Hippo pathway alterations were linked to improved immunotherapy outcomes. These findings suggest connections between the Hippo pathway and PD-L1 expression, warranting further clinical and functional investigations. The research advances our understanding of PD-L1 expression's genomic context and immunotherapy response in EGFR/ALK wild-type lung adenocarcinoma.

A comprehensive integrated gene network construction to explore the essential role of Notch 1 in lung adenocarcinoma (LUAD)

The heterogeneous biological landscape of non-small cell lung cancer (NSCLC) is largely attributed to the activation of Notch signalling pathway. Among the Notch family transmembrane proteins, neurogenic locus notch homolog protein1 (NOTCH1) is a putative oncogene in NSCLC which activates the pathway as negative prognostic factor. This study aims to explore integrated network approach in lung adenocarcinoma (LUAD) especially linked to the notch pathway and its receptors. Our gene set enrichment analysis reveals the key Notch pathway genes are predominantly down regulated in LUAD. There were 675 genes with a total of 6517 functional interactions and 6 densely connected clusters of 38 miRNAs, 84 transcription factors with 156 edges identified through network construction. Here we report five key genes namely NOTCH1, CDH1, ERBB2, GAPDH and COL1A1 significantly enriched in Notch pathway which are further validated through the KM plot, box plots, stage plots and TIMER analysis. In addition, the NOTCH1 receptor is strongly linked to the immune checkpoint inhibitor CD274 (PD-L1) and can be considered as prognostic marker and tumour suppressor gene in LUAD which surely provide the basis for early diagnosis and futuristic immunotherapeutic targets for LUAD.Communicated by Ramaswamy H. Sarma.

Enhancing immunogenic responses through CDK4/6 and HIF2α inhibition in Merkel cell carcinoma

Approximately 50% of Merkel cell carcinoma (MCC) patients facing this highly aggressive skin cancer initially respond positively to PD-1-based immunotherapy. Nevertheless, the recurrence of MCC post-immunotherapy emphasizes the pressing need for more effective treatments. Recent research has highlighted Cyclin-dependent kinases 4 and 6 (CDK4/6) as pivotal cell cycle regulators gaining prominence in cancer studies. This study reveals that the CDK4/6 inhibitor, palbociclib can enhance PD-L1 gene transcription and surface expression in MCC cells by activating HIF2α. Inhibiting HIF2α with TC-S7009 effectively counteracts palbociclib-induced PD-L1 transcription and significantly intensifies cell death in MCC. Simultaneously, co-targeting CDK4/6 and HIF2α boosts ROS levels while suppressing SLC7A11, a key regulator of cellular redox balance, promoting ferroptosis- a form of immunogenic cell death linked to iron. Considering the rising importance of immunogenic cell death in immunotherapy, this strategy holds promise for improving future MCC treatments, markedly increasing immunogenic cell death various across various MCC cell lines, thus advancing cancer immunotherapy.

Optimization of cancer immunotherapy on the basis of programmed death ligand-1 distribution and function

Programmed cell death protein-1 (PD-1)/programmed death ligand-1 (PD-L1) immune checkpoint blockade as a breakthrough in cancer immunotherapy has shown unprecedented positive outcomes in the clinic. However, the overall effectiveness of PD-L1 antibody is less than expected. An increasing number of studies have demonstrated that PD-L1 is widely distributed and expressed not only on the cell membrane but also on the inside of the cells as well as on the extracellular vesicles secreted by tumour cells. Both endogenous and exogenous PD-L1 play significant roles in influencing the therapeutic effect of anti-tumour immunity. Herein, we mainly focused on the distribution and function of PD-L1 and further summarized the potential targeted therapeutic strategies. More importantly, in addition to taking the overall expression abundance of PD-L1 as a predictive indicator for selecting corresponding PD-1/PD-L1 monoclonal antibodies (mAbs), we also proposed that personalized combination therapies based on the different distribution of PD-L1 are worth attention to achieve more efficient and effective therapeutic outcomes in cancer patients. LINKED ARTICLES: This article is part of a themed issue on Cancer Microenvironment and Pharmacological Interventions. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.2/issuetoc.

PD-1/PD-L1 pathway: Current research in breast cancer

INTRODUCTION

Immunotherapy has shown encouraging outcomes in breast cancer (BC) treatment in recent years. The programmed cell death ligand 1 (PD-L1) transmembrane protein is suggested to function as a co-inhibitory factor in the immune response, where it collaborates with programmed cell death protein 1 (PD-1) to stimulate apoptosis, suppress cytokine release from PD-1 positive cells, and limit the growth of PD-1 positive cells. Furthermore, in many malignancies, PD-L1 reduces the immune system's response to neoplastic cells. These observations suggest that the PD-1/PD-L1 axis plays a vital role in cancer therapy and the regulation of cancer immune escape mechanisms. This review aimed to provide an overview of the functions of PD-1 and PD-L1 in BC cancer therapy.

METHODS

This research design is a literature review. The style is a traditional review on topics or variables relating to the PD-1/PD-L1 pathway. A literature search was carried out using three online databases.

RESULTS

The search using the keywords yielded a total of 248 studies. Each result was filtered again according to the inclusion and exclusion criteria, resulting in a final total of 4 studies to be included in the literature review.

CONCLUSIONS

The combination of PD-1/PD-L1 is essential for many malignancies. According to the evidence presented, this combination presents both an opportunity and a challenge in cancer treatment. Since many solid cancers, especially BC, express high levels of PD-1/PD-L1, cancer treatment mainly involves targeted therapies.

The diverse effects of cisplatin on tumor microenvironment: Insights and challenges for the delivery of cisplatin by nanoparticles

Cisplatin is a well-known platinum-based chemotherapy medication that is widely utilized for some malignancies. Despite the direct cytotoxic consequences of cisplatin on tumor cells, studies in the recent decade have revealed that cisplatin can also affect different cells and their secretions in the tumor microenvironment (TME). Cisplatin has complex impacts on the TME, which may contribute to its anti-tumor activity or drug resistance mechanisms. These regulatory effects of cisplatin play a paramount function in tumor growth, invasion, and metastasis. This paper aims to review the diverse impacts of cisplatin and nanoparticles loaded with cisplatin on cancer cells and also non-cancerous cells in TME. The impacts of cisplatin on immune cells, tumor stroma, cancer cells, and also hypoxia will be discussed in the current review. Furthermore, we emphasize the challenges and prospects of using cisplatin in combination with other adjuvants and therapeutic modalities that target TME. We also discuss the potential synergistic effects of cisplatin with immune checkpoint inhibitors (ICIs) and other agents with anticancer potentials such as polyphenols and photosensitizers. Furthermore, the potential of nanoparticles for targeting TME and better delivery of cisplatin into tumors will be discussed.

The programed death-1/programed death ligand-1 axis and its potential as a therapeutic target for virus-associated tumours

As an important and serious condition impacting human health, the diagnosis, and treatment of tumours is clinically vital because tumour cell immune escape sustains tumour development. Programed death ligand-1 (PD-L1) on tumour cell surfaces binds to the programed death-1 (PD-1), inhibits T cell activation, and induces apoptosis, and incapacitates cells. This allows tumour cells to evade recognition and clearance by the immune system, thereby permitting tumour occurrence, and development and poor prognosis outcomes in patients with tumours. Currently, anti-PD-1/PD-L1 immunotherapy has become pivotal in tumour treatment. Pathogens, especially viruses, are important factors which induce many tumours. In this article, we examine associations between Epstein-Barr virus, human papilloma virus, hepatitis B virus, hepatitis C virus, and human immunodeficiency virus type 1-related tumours and PD-1/PD-L1 axis.

Prognostic value of PD‑L1 expression and CD68 macrophages in tumor nest of patients with primary gastric cancer

The programmed death receptor 1/programmed death receptor ligand 1 axis (PD-1/PD-L1) is involved in tumor immune escape and is a potential prognostic biomarker and anti-tumor immunotherapy target in patients with gastric cancer (GC). However, the results of studies obtained in recent years have been inconsistent. The present study aimed to determine the possible predictive significance of PD-L1 in conjunction with three proteins linked with PD-L1 regulation in patients with primary GC. In the present study, the PD-L1, human epidermal growth factor receptor 2 (HER2), cluster of differentiation (CD)133 and microphage-associated CD68 expression levels were identified by multiplexed immunohistochemistry and assessed by automated pathological analysis system in 93 GC tumors and neighboring normal tissues arrayed on the same tissue microarray. All four proteins were statistically analyzed in relation to the clinicopathological characteristics. The expression levels of HER2, CD133 and CD68 were considerably higher in cancer tissues compared with neighboring normal tissues (P<0.05), however, the reverse trend was detected for PD-L1 expression (P=0.0577), particularly in tumor nest (TN; P<0.05). There was no significant correlation between the HER2 and CD133 expression levels and clinicopathological factors. However, significant relationships were found between PD-L1 expression and the TNM stage, pathological differentiation and survival status of patients (P<0.05). Moreover, survival time was prolonged in individuals with elevated PD-L1 expression in TN and GC tissues, but no significant correlation was identified (P=0.0881). The CD68 expression level in tumor stroma, but not in TN, was significantly correlated with poor pathological differentiation in patients with GC (P<0.05). However, PD-L1+CD68+ macrophages were strongly related to lower tumor size (diameter <5 cm), early TNM stage (stage I+II), good pathological differentiation and overall survival in TN (P<0.05). In conclusion, PD-L1+CD68+ macrophage infiltration in TN might be a potential indicator of prognosis in patients with primary GC and merits further investigation.

PD-L1 and AKT Overexpressing Adipose-Derived Mesenchymal Stem Cells Enhance Myocardial Protection by Upregulating CD25+ T Cells in Acute Myocardial Infarction Rat Model

This study explores the synergistic impact of Programmed Death Ligand 1 (PD-L1) and Protein Kinase B (Akt) overexpression in adipose-derived mesenchymal stem cells (AdMSCs) for ameliorating cardiac dysfunction after myocardial infarction (MI). Post-MI adult Wistar rats were allocated into four groups: sham, MI, ADMSC treatment, and ADMSCs overexpressed with PD-L1 and Akt (AdMSC-PDL1-Akt) treatment. MI was induced via left anterior descending coronary artery ligation, followed by intramyocardial AdMSC injections. Over four weeks, cardiac functionality and structural integrity were assessed using pressure-volume analysis, infarct size measurement, and immunohistochemistry. AdMSC-PDL1-Akt exhibited enhanced resistance to reactive oxygen species (ROS) in vitro and ameliorated MI-induced contractile dysfunction in vivo by improving the end-systolic pressure-volume relationship and preload-recruitable stroke work, together with attenuating infarct size. Molecular analyses revealed substantial mitigation in caspase3 and nuclear factor-κB upregulation in MI hearts within the AdMSC-PDL1-Akt group. Mechanistically, AdMSC-PDL1-Akt fostered the differentiation of normal T cells into CD25+ regulatory T cells in vitro, aligning with in vivo upregulation of CD25 in AdMSC-PDL1-Akt-treated rats. Collectively, PD-L1 and Akt overexpression in AdMSCs bolsters resistance to ROS-mediated apoptosis in vitro and enhances myocardial protective efficacy against MI-induced dysfunction, potentially via T-cell modulation, underscoring a promising therapeutic strategy for myocardial ischemic injuries.

Understanding immune checkpoints and PD-1/PD-L1-mediated immune resistance towards tumour immunotherapy

Immunotherapy has emerged as a transformative approach in the treatment of various cancers, offering new hope for patients previously faced with limited treatment options. A cornerstone of cancer immunotherapy lies in targeting immune checkpoints, particularly the programmed cell death protein-1 (PD-1) and programmed death-ligand 1 (PD-L1) pathway. Immune checkpoints serve as crucial regulators of the immune response, preventing excessive immune activity and maintaining self-tolerance. PD-1, expressed on the surface of T cells, and its ligand PD-L1, expressed on various cell types, including cancer cells and immune cells, play a central role in this regulatory process. Although the success rate associated with these immunotherapies is very promising, most patients still show intrinsic or acquired resistance. Since the mechanisms related to PD-1/PD-L1 resistance are not well understood, an in-depth analysis is necessary to improve the success rate of anti-PD-1/PD-L1 therapy. Hence, here we provide an overview of PD-1, its ligand PD-L1, and the resistance mechanism towards PD-1/PD-L1. Furthermore, we have discussed the plausible solution to increase efficacy and clinical response. For the following research, joint endeavours of clinicians and basic scientists are essential to address the limitation of resistance towards immunotherapy.

PD-1 and PD-L1 inhibitors in cold colorectal cancer: challenges and strategies

Colorectal cancer (CRC) is the second most common cause of cancer mortality, with mismatch repair proficient (pMMR) and/or microsatellite stable (MSS) CRC making up more than 80% of metastatic CRC. Programmed death-ligand 1 (PD-L1) and programmed death 1 (PD-1) immune checkpoint inhibitors (ICIs) are approved as monotherapy in many cancers including a subset of advanced or metastatic colorectal cancer (CRC) with deficiency in mismatch repair (dMMR) and/or high microsatellite instability (MSI-H). However, proficient mismatch repair and microsatellite stable (pMMR/MSS) cold CRCs have not shown clinical response to ICIs alone. To potentiate the anti-tumor response of PD-L1/PD-1 inhibitors in patients with MSS cold cancer, combination strategies currently being investigated include dual ICI, and PD-L1/PD-1 inhibitors in combination with chemotherapy, radiotherapy, vascular endothelial growth factor (VEGF) /VEGF receptor (VEGFR) inhibitors, mitogen-activated protein kinase (MEK) inhibitors, and signal transducer and activation of transcription 3 (STAT3) inhibitors. This paper will review the mechanisms of PD-1/PD-L1 ICI resistance in pMMR/MSS CRC and potential combination strategies to overcome this resistance, summarize the published clinical experience with different combination therapies, and make recommendations for future avenues of research.

The expression changes of PD-L1 and immune response mediators are related to the severity of primary bone tumors

The expression pattern, diagnostic value, and association of PD-L1, IFN-γ and TGF-β with bone tumor type, severity, and relapse are determined in this study. 300 human samples from patients with osteosarcoma, Ewing sarcoma, and GCT were enrolled. The PD-L1 gene and protein expression were assessed by qRT-PCR and immunohistochemistry, respectively. ELISA and flow cytometry was used to detect cytokines and CD4/CD8 T cell percentages, respectively. A considerable increase in PD-L1 level was detected in bone tumor tissues at both gene and protein levels that was considerable in osteosarcoma and Ewing sarcoma. A positive correlation was detected regarding the PD-L1 and tumor metastasis and recurrence in osteosarcoma and Ewing sarcoma. The increased IFN-γ level was detected in patients with metastatic, and recurrent osteosarcoma tumors that were in accordance with the level of TGF-β in these samples. The simultaneous elevation of IFN-γ and TGF-β was detected in Ewing sarcoma and GCT, also the CD4 + /CD8 + ratio was decreased significantly in patients with osteosarcoma compared to GCT tumors. The elevated levels of PD-L1, TGF- β, and IFN-γ were associated with bone tumor severity that can provide insights into the possible role of this axis in promoting immune system escape, suppression, and tumor invasion.

Humanized disulfide-stabilized diabody against fibroblast growth factor-2 inhibits PD-L1 expression and epithelial-mesenchymal transition in hepatoma cells through STAT3

Fibroblast growth factor 2 (FGF2) plays an important role in tumor angiogenesis. Humanized disulfide-stable double-chain antibody against fibroblast growth factor-2 (anti-FGF2 ds-Diabody) is a small molecule antibody with good tissue permeability and low immunogenicity, which has potential in tumor-targeted therapy. This study intended to investigate the effect of anti-FGF2 ds-Diabody on the migration and expression of programmed death-ligand1 (PD-L1) in hepatocellular carcinoma (HCC) cells. The anti-FGF2 ds-Diabody was expressed under methanol induction and purified with Ni2+ -affinity chromatography. Anti-FGF2 ds-Diabody significantly inhibited cell viability and proliferation in SK-Hep1 and HepG2 cells as confirmed by CCK-8 assays and colony formation assays. Western blot assays indicated that the proliferation of SK-Hep1 and HepG2 cells was inhibited by anti-FGF2 ds-Diabody through inhibiting the phosphorylation activation of AKT and MAPK. The results of transwell and western blot assays showed that the migration and invasion of SK-Hep1 and HepG2 cells were suppressed by anti-FGF2 ds-Diabody by affecting the epithelial-mesenchymal transition (EMT) process. Meanwhile, anti-FGF2 ds-Diabody inhibited the expression of PD-L1, and STAT3 participated in this process. Analysis of RT-PCR and Western blot suggested that fibroblast growth factor receptor 4 inhibitor 1 (FGFR4-IN-1) suppressed the expression of PD-L1, while STAT3 overexpression reversed this inhibitory effect. In addition, overexpression of STAT3 promoted migration and invasion and restored the suppressive effect of anti-FGF2 ds-Diabody on EMT. In conclusion, anti-FGF2 ds-Diabody could inhibit the expression of PD-L1 and EMT of hepatoma cells through FGF2/FGFR4/STAT3 axis. These results suggested that anti-FGF2 ds-Diabody has potential clinical application in inhibiting metastasis and immune escape of hepatocellular carcinoma.

Crosstalk between PD-L1 and Jak2-Stat3/ MAPK-AP1 signaling promotes oral cancer progression, invasion and therapy resistance

BACKGROUND

Programmed cell death ligand-1 (PD-L1)is an antitumor immunity molecule and a great target to cure oral cancer; nonetheless, the limited success can be attributed to many complex pathways and tumor-related interferences.

METHODS

In the present study, 150 human oral squamous cell carcinoma (OSCC) tissue samples, including 17 adjacent normals, 56 primary tumors, 47 invasive tumors, and 30 therapy-resistant (RT) samples, were included. The parental/cisplatin-resistant (CisR-SCC4/9) cells were utilized for overexpression (Jak1-3 wild type and catalytically inactive), knockdown (PD-L1 siRNA), targeting MAPK/PI3K/Jak-Stat pathways (SMIs) and checking microsomes. The expression of PD-L1, transcription factors (TFs), signaling pathways, survival/apoptosis, therapy resistance, and invasiveness-related molecules/their activity were determined by RT-PCR, Immunohistochemistry, Western blot, Gelatin Zymography, and MTT assay.

RESULTS

Advanced OSCC tumors (invasive and drug-resistance), CisR-SCC4/9 cells, and secretory exosomes (CisR-SCC4/9) were found with increased PD-L1 expression. PD-L1 mRNA/protein showed a positive correlation with different TFs (AP1 > Stat3 > c-myc > NFκB) in tumor samples. The PD-L1 expression was more influenced by Jak-Stat/ MAPK-AP1 pathways over PI3K. The ectopic expression of Jak1-3 suggests Jak2 inducted PD-L1 level over Jak1/Jak3. Finally, PD-L1 directly supports survival (Bcl-xL, Bax, cleaved caspase-3), invasion (MMP2/9), and drug-resistance (ALDH-1A1/-3A1) program in OSCC through its link with several molecules.

CONCLUSIONS

PD-L1 was regulated mainly by the Jak2-Stat3/ MAPK-AP1 pathway, and besides the routine immunological functions, it supports OSCC survival, invasion, and therapy resistance. PD-L1 can be used as an indicator of severity and can be targeted along with Jak2-Stat3/ MAPK-AP1 for a better outcome OSCC.

An In Vivo Self-Assembled Bispecific Nanoblocker for Enhancing Tumor Immunotherapy

Anti-PD-L1 monoclonal antibody has achieved substantial success in tumor immunotherapy by T-cells activation. However, the excessive accumulation of extracellular matrix components induced by unsatisfactory T-cells infiltration and poor tumor penetration of antibodies make it challenging to realize efficient tumor immunotherapy. Herein, a peptide-based bispecific nanoblocker (BNB) strategy is reported for in situ construction of CXCR4/PD-L1 targeted nanoclusters on the surface of tumor cells that are capable of boosting T-cells infiltration through CXCR4 blockage and enhancing T-cells activation by PD-L1 occupancy, ultimately realizing high-performance tumor immunotherapy. Briefly, the BNB strategy selectively recognizes and bonds CXCR4/PD-L1 with deep tumor penetration, which rapidly self-assembles into nanoclusters on the surface of tumor cells. Compared to the traditional bispecific antibody, BNB exhibits an intriguing metabolic behavior, that is, the elimination half-life (t1/2 ) of BNB in the tumor is 69.3 h which is ≈50 times longer than that in the plasma (1.4 h). The higher tumor accumulation and rapid systemic clearance overcome potential systemic side effects. Moreover, the solid tumor stress generated by excessive extracellular matrix components is substantially reduced to 44%, which promotes T-cells infiltration and activation for immunotherapy efficacy. Finally, these findings substantially strengthen and extend clinical applications of PD-1/PD-L1 immunotherapy.

The potential role of reprogrammed glucose metabolism: an emerging actionable codependent target in thyroid cancer

Although the incidence of thyroid cancer is increasing year by year, most patients, especially those with differentiated thyroid cancer, can usually be cured with surgery, radioactive iodine, and thyroid-stimulating hormone suppression. However, treatment options for patients with poorly differentiated thyroid cancers or radioiodine-refractory thyroid cancer have historically been limited. Altered energy metabolism is one of the hallmarks of cancer and a well-documented feature in thyroid cancer. In a hypoxic environment with extreme nutrient deficiencies resulting from uncontrolled growth, thyroid cancer cells utilize "metabolic reprogramming" to satisfy their energy demand and support malignant behaviors such as metastasis. This review summarizes past and recent advances in our understanding of the reprogramming of glucose metabolism in thyroid cancer cells, which we expect will yield new therapeutic approaches for patients with special pathological types of thyroid cancer by targeting reprogrammed glucose metabolism.

Safety and clinical efficacy of sintilimab (anti-PD-1) in pediatric patients with advanced or recurrent malignancies in a phase I study

The aim of this phase I study is to evaluate, for the first time, the safety and efficacy of sintilimab in pediatric patients diagnosed with advanced or recurrent malignancies. During the dose escalation phase, patients received a single intravenous infusion of sintilimab at varying doses of 1, 3, and 10 mg/kg. The primary endpoints included the identification of dose-limiting toxicities (DLTs) as well as the evaluation of safety and tolerance. Secondary endpoints focused on assessing objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). A total of 29 patients were enrolled, including 10 individuals diagnosed with Hodgkin lymphoma (HL) and 19 patients with various other tumor categories. Notably, diverse pathological types such as thymoma, choroid plexus carcinoma, and NK/T-cell lymphoma were also included in the study cohort. By the safety data cutoff, most adverse events were grade 1 or 2, with grade 3 or higher treatment-related adverse events (TRAE) occurring in 10% of patients. Among the 27 evaluated subjects, four achieved confirmed complete response (CR) while seven patients exhibited confirmed partial response (PR). Additionally, seven patients maintained disease (SD) during the study period. Notably, sintilimab demonstrated remarkable tolerability without DLTs and exhibited promising anti-tumor effects in pediatric HL. Whole-exome sequencing (WES) was conducted in 15 patients to assess the mutational landscape and copy number variation (CNV) status. The completion of this phase I study establishes the foundation for potential combination regimens involving sintilimab in childhood cancer treatment. The trial is registered on ClinicalTrials.gov with the identifier NCT04400851.

Engineering Cell-Derived Nanovesicles for Targeted Immunomodulation

Extracellular vesicles (EVs) show promise for targeted drug delivery but face production challenges with low yields. Cell-derived nanovesicles (CDNVs) made by reconstituting cell membranes could serve as EV substitutes. In this study, CDNVs were generated from mesenchymal stem cells by extrusion. Their proteomic composition, in vitro and in vivo toxicity, and capacity for loading RNA or proteins were assessed. Compared with EVs, CDNVs were produced at higher yields, were comprised of a broader range of proteins, and showed no detrimental effects on cell proliferation, DNA damage, or nitric oxide production in vitro or on developmental toxicity in vivo. CDNVs could be efficiently loaded with RNA and engineered to modify surface proteins. The feasibility of generating immunomodulatory CDNVs was demonstrated by preparing CDNVs with enhanced surface expression of PD1, which could bind to PD-L1 expressing tumor cells, enhance NK and T cell degranulation, and increase immune-mediated tumor cell death. These findings demonstrate the adaptability and therapeutic promise of CDNVs as promising substitutes for natural EVs that can be engineered to enhance immunomodulation.

Autophagy as a Target for Non-Immune Intrinsic Functions of Programmed Cell Death-Ligand 1 in Cancer

Autophagy is a catabolic process that is essential to the maintenance of homeostasis through the cellular recycling of damaged organelles or misfolded proteins, which sustains energy balance. Additionally, autophagy plays a dual role in modulating the development and progression of cancer and inducing a survival strategy in tumoral cells. Programmed cell death-ligand 1 (PD-L1) modulates the immune response and is responsible for maintaining self-tolerance. Because tumor cells exploit the PD-L1-PD-1 interaction to subvert the immune response, immunotherapy has been developed based on the use of PD-L1-blocking antibodies. Recent evidence has suggested a bidirectional regulation between autophagy and PD-L1 molecule expression in tumor cells. Moreover, the research into the intrinsic properties of PD-L1 has highlighted new functions that are advantageous to tumor cells. The relationship between autophagy and PD-L1 is complex and still not fully understood; its effects can be context-dependent and might differ between tumoral cells. This review refines our understanding of the non-immune intrinsic functions of PD-L1 and its potential influence on autophagy, how these could allow the survival of tumor cells, and what this means for the efficacy of anti-PD-L1 therapeutic strategies.

Comparison of PD-L1 expression and MMR status between primary and matched metastatic lesions in patients with cervical cancer

PURPOSE

Programmed death-ligand 1 (PD-L1) and DNA mismatch repair (MMR) are considered predictive biomarkers for immunotherapy in cervical cancer. However, their expression in primary tumors and metastases does not always match affecting the course of treatment. We investigated the consistency of their expression in primary and matched recurrent/metastatic lesions from patients with cervical cancer.

METHODS

Primary and matched recurrent/metastatic specimens from patients with recurrent cervical cancer (n = 194) were stained for PD-L1 and MMR (MLHI, MSH6, MSH2, and PMS2) using immunohistochemistry. The degree of consistency of PD-L1 and MMR expression in these lesions was analyzed.

RESULTS

The inconsistency rate of PD-L1 expression in primary and recurrent/metastatic lesions was 33.0%, and it varied between the recurrence sites. Positive PD-L1 rate in primary lesions was lower (15.4%) than that in recurrent/metastatic lesions (30.4%). The discordance rate of MMR expression between primary and recurrent/metastatic lesions was 4.1%.

CONCLUSION

We conclude that to use PD-L1 as a predictive biomarker for immunotherapy, analysis of both metastatic and primary lesions may be required. High consistency rate of MMR expression between primary and metastatic lesions suggests that testing primary lesions alone can be sufficient for guiding the course of therapy, thereby solving the difficulty of obtaining recurrent/metastatic specimens in clinic.

MicroRNA-326 negatively regulates CD155 expression in lung adenocarcinoma

Treatment with immune checkpoint inhibitors induces a durable response in some patients with non-small-cell lung cancer, but eventually gives rise to drug resistance. Upregulation of CD155 expression is implicated as one mechanism of resistance to programmed death receptor-1 (PD-1)/PD-1 ligand (PD-L1) inhibitors, and it is therefore important to characterize the mechanisms underlying regulation of CD155 expression in tumor cells. The aim of this study was to identify microRNAs (miRNAs) that might regulate CD155 expression at the posttranscriptional level in lung cancer. Comprehensive miRNA screening with target prediction programs and a dual-luciferase reporter assay identified miR-346, miR-328-3p, miR-326, and miR-330-5p as miRNAs that bind to the 3'-UTR of CD155 mRNA. Forced expression of these miRNAs suppressed CD155 expression in lung cancer cell lines. Immunohistochemical staining of CD155 in tissue specimens from 57 patients with lung adenocarcinoma revealed the median tumor proportion score for CD155 to be 68%. The abundance of miR-326 in these specimens with a low level of CD155 expression was significantly greater than in specimens with a high level (p < 0.005). Our results thus suggest that miR-326 negatively regulates CD155 expression in lung adenocarcinoma and might therefore play a role in the development of resistance to PD-1/PD-L1 inhibitors.

Ponatinib delays the growth of solid tumours by remodelling immunosuppressive tumour microenvironment through the inhibition of induced PD-L1 expression

BACKGROUND

Therapeutic modalities including chemo, radiation, immunotherapy, etc. induce PD-L1 expression that facilitates the adaptive immune resistance to evade the antitumour immune response. IFN-γ and hypoxia are some of the crucial inducers of PD-L1 expression in tumour and systemic microenvironment which regulate the expression of PD-L1 via various factors including HIF-1α and MAPK signalling. Hence, inhibition of these factors is crucial to regulate the induced PD-L1 expression and to achieve a durable therapeutic outcome by averting the immunosuppression.

METHODS

B16-F10 melanoma, 4T1 breast carcinoma, and GL261 glioblastoma murine models were established to investigate the in vivo antitumour efficacy of Ponatinib. Western blot, immunohistochemistry, and ELISA were performed to determine the effect of Ponatinib on the immunomodulation of tumour microenvironment (TME). CTL assay and flow cytometry were such as p-MAPK, p-JNK, p-Erk, and cleaved caspase-3 carried out to evaluate the systemic immunity induced by Ponatinib. RNA sequencing, immunofluorescence and Western blot analysis were used to determine the mechanism of PD-L1 regulation by Ponatinib. Antitumour immunity induced by Ponatinib were compared with Dasatinib.

RESULTS

Here, Ponatinib treatment delayed the growth of tumours by inhibiting PD-L1 and modulating TME. It also downregulated the level of PD-L1 downstream signalling molecules. Ponatinib enhanced the CD8 T cell infiltration, regulated Th1/Th2 ratio and depleted tumour associated macrophages (TAMs) in TME. It induced a favourable systemic antitumour immunity by enhancing CD8 T cell population, tumour specific CTL activity, balancing the Th1/Th2 ratio and lowering PD-L1 expression. Ponatinib inhibited FoxP3 expression in tumour and spleen. RNA sequencing data revealed that Ponatinib treatment downregulated the genes related to transcription including HIF-1α. Further mechanistic studies showed that it inhibited the IFN-γ and hypoxia induced PD-L1 expression via regulating HIF-1α. Dasatinib was used as control to prove that Ponatinib induced antitumour immunity is via PD-L1 inhibition mediated T cell activation.

CONCLUSIONS

RNA sequencing data along with rigorous in vitro and in vivo studies revealed a novel molecular mechanism by which Ponatinib can inhibit the induced PD-L1 levels via regulating HIF-1α expression which leads to modulation of tumour microenvironment. Thus, our study provides a novel therapeutic insight of Ponatinib for the treatment of solid tumours where it can be used alone or in combination with other drugs which are known to induce PD-L1 expression and generate adaptive resistance.

Prognostic Significance of β-Catenin in Relation to the Tumor Immune Microenvironment in Oral Cancer

The aim of this study was to investigate the prognostic relevance of β-catenin expression in oral squamous cell carcinoma (OSCC) and to explore relationships with the tumor immune microenvironment. Expression of β-catenin and PD-L1, as well as lymphocyte and macrophage densities, were evaluated by immunohistochemistry in 125 OSCC patient specimens. Membranous β-catenin expression was detected in 102 (81.6%) and nuclear β-catenin in 2 (1.6%) tumors. There was an association between β-catenin expression, tumoral, and stromal CD8+ T-cell infiltration (TIL) and also the type of tumor immune microenvironment (TIME). Tumors harboring nuclear β-catenin were associated with a type II TIME (i.e., immune ignorance defined by a negative PD-L1 expression and low CD8+ TIL density), whereas tumors with membranous β-catenin expression were predominantly type IV (i.e., immune tolerance defined by negative PD-L1 and high CD8+ TIL density). Combined, but not individual, high stromal CD8+ TILs and membranous β-catenin expression was independently associated with better disease-specific survival (HR = 0.48, p = 0.019). Taken together, a combination of high stromal CD8+ T-cell infiltration and membranous β-catenin in the tumor emerges as an independent predictor of better survival in OSCC patients.

Molecular Insight into Prostate Cancer: Preventive Role of Selective Bioactive Molecules

Prostate cancer (CaP) is one of the most prevalent male malignancies, accounting for a considerable number of annual mortalities. However, the prompt identification of early-stage CaP often faces delays due to diverse factors, including socioeconomic inequalities. The androgen receptor (AR), in conjunction with various other signaling pathways, exerts a central influence on the genesis, progression, and metastasis of CaP, with androgen deprivation therapy (ADT) serving as the primary therapeutic strategy. Therapeutic modalities encompassing surgery, chemotherapy, hormonal intervention, and radiotherapy have been formulated for addressing early and metastatic CaP. Nonetheless, the heterogeneous tumor microenvironment frequently triggers the activation of signaling pathways, culminating in the emergence of chemoresistance, an aspect to which cancer stem cells (CSCs) notably contribute. Phytochemicals emerge as reservoirs of bioactive agents conferring manifold advantages against human morbidity. Several of these phytochemicals demonstrate potential chemoprotective and chemosensitizing properties against CaP, with selectivity exhibited towards malignant cells while sparing their normal counterparts. In this context, the present review aims to elucidate the intricate molecular underpinnings associated with metastatic CaP development and the acquisition of chemoresistance. Moreover, the contributions of phytochemicals to ameliorating CaP initiation, progression, and chemoresistance are also discussed.

Thymoquinone, a Novel Multi-Strike Inhibitor of Pro-Tumorigenic Breast Cancer (BC) Markers: CALR, NLRP3 Pathway and sPD-L1 in PBMCs of HR+ and TNBC Patients

Breast cancer (BC) is not only a mass of malignant cells but also a systemic inflammatory disease. BC pro-tumorigenic inflammation has been shown to promote immune evasion and provoke BC progression. The NOD-like receptor (NLR) family pyrin domain-containing protein 3 (NLRP3) inflammasome is activated when pattern recognition receptors (PRRs) sense danger signals such as calreticulin (CALR) from damaged/dying cells, leading to the secretion of interleukin-1β (IL-1β). CALR is a novel BC biological marker, and its high levels are associated with advanced tumors. NLRP3 expression is strongly correlated with an elevated proliferative index Ki67, BC progression, metastasis, and recurrence in patients with hormone receptor-positive (HR+) and triple-negative BC (TNBC). Tumor-associated macrophages (TAMs) secrete high levels of IL-1β promoting endocrine resistance in HR+ BC. Recently, an immunosuppressive soluble form of programmed death ligand 1 (sPD-L1) has been identified as a novel prognostic biomarker in triple-negative breast cancer (TNBC) patients. Interestingly, IL-1β induces sPD-L1 release. BC Patients with elevated IL-1β and sPD-L1 levels show significantly short progression-free survival. For the first time, this study aims to investigate the inhibitory impact of thymoquinone (TQ) on CALR, the NLRP3 pathway and sPD-L1 in HR+ and TNBC. Blood samples were collected from 45 patients with BC. The effect of differing TQ concentrations for different durations on the expression of CALR, NLRP3 complex components and IL-1β as well as the protein levels of sPD-L1 and IL-1β were investigated in the peripheral blood mononuclear cells (PBMCs) and TAMs of TNBC and HR+ BC patients, respectively. The findings showed that TQ significantly downregulated the expression of CALR, NLRP3 components and IL-1β together with the protein levels of secreted IL-1β and sPD-L1. The current findings demonstrated novel immunomodulatory effects of TQ, highlighting its potential role not only as an excellent adjuvant but also as a possible immunotherapeutic agent in HR+ and TNBC patients.

Development of a CD8+ T cell-based molecular classification for predicting prognosis and heterogeneity in triple-negative breast cancer by integrated analysis of single-cell and bulk RNA-sequencing

Background

Triple-negative breast cancer (TNBC), although the most intractable subtype, is characterized by abundant immunogenicity, which enhances responsiveness to immunotherapeutic measures.

Methods

First, we identified CD8+ T cell core genes (TRCG) based on single-cell sequence and traditional transcriptome sequencing and then used this data to develop a first-of-its-kind classification system based on CD8+ T cells in patients with TNBC. Next, TRCG-related patterns were systematically analyzed, and their correlation with genomic features, immune activity (microenvironment associated with immune infiltration), and clinicopathological characteristics were assessed in the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), the Cancer Genome Atlas (TCGA), GSE103091, GSE96058 databases. Additionally, a CD8+ T cell-related prognostic signature (TRPS) was developed to quantify a patient-specific TRCG pattern. What's more, the genes-related TRPS was validated by polymerase chain reaction (PCR) experiment.

Results

This study, for the first time, distinguished two subsets in patients with TNBC based on the TRCG. The immune microenvironment and prognostic stratification between these have distinct heterogeneity. Furthermore, this study constructed a novel scoring system named TRPS, which we show to be a robust prognostic marker for TNBC that is related to the intensity of immune infiltration and immunotherapy. Moreover, the levels of genes related the TRPS were validated by quantitative Real-Time PCR.

Conclusions

Consequently, this study unraveled an association between the TRCG and the tumor microenvironment in TNBC. TRPS model represents an effective tool for survival prediction and treatment guidance in TNBC that can also help identify individual variations in TME and stratify patients who are sensitive to anticancer immunotherapy.

Endocrine immune-related adverse effects of immune-checkpoint inhibitors

INTRODUCTION

Immune-checkpoint inhibitor therapy modulates the response of the immune system acting against cancer. Two pathways impacted by this kind of treatment are the CTLA4 and the PD-1/PD-L1 pathways. ICI therapy can trigger autoimmune adverse effects, known as immune-related Adverse Events (irAEs).

AREAS COVERED

This review focuses on irAEs which affect the endocrine system. This review elucidates the pathways used by these drugs with a focus on the hypothetical pathogenesis at their basis. In fact, the pathophysiology of irAEs concerns the possibility of an interaction between cellular autoimmunity, humoral immunity, cytokines, chemokines, and genetics. The endocrine irAEs examined are thyroid dysfunctions, immune related-hypophysitis, diabetes, peripheral adrenal insufficiency, and hypoparathyroidism.

EXPERT OPINION

There is still much to investigate in endocrine irAES of checkpoint inhibitors. In the future, checkpoint inhibitors will be increasingly utilized therapies, and therefore it is crucial to find the proper diagnostic-therapeutic program for irAEs, especially as endocrine irAEs are nonreversible and require lifelong replacement therapies.

Short-chain fatty acids in cancer pathogenesis

Cancer is a multi-step process that can be viewed as a cellular and immunological shift away from homeostasis in response to selected infectious agents, mutations, diet, and environmental carcinogens. Homeostasis, which contributes importantly to the definition of "health," is maintained, in part by the production of short-chain fatty acids (SCFAs), which are metabolites of specific gut bacteria. Alteration in the composition of gut bacteria, or dysbiosis, is often a major risk factor for some two dozen tumor types. Dysbiosis is often characterized by diminished levels of SCFAs in the stool, and the presence of a "leaky gut," permitting the penetration of microbes and microbial derived molecules (e.g., lipopolysaccharides) through the gut wall, thereby triggering chronic inflammation. SCFAs attenuate inflammation by inhibiting the activation of nuclear factor kappa B, by decreasing the expression of pro-inflammatory cytokines such as tumor necrosis factor alpha, by stimulating the expression of anti-inflammatory cytokines such as interleukin-10 and transforming growth factor beta, and by promoting the differentiation of naïve T cells into T regulatory cells, which down-regulate immune responses by immunomodulation. SCFA function epigenetically by inhibiting selected histone acetyltransferases that alter the expression of multiple genes and the activity of many signaling pathways (e.g., Wnt, Hedgehog, Hippo, and Notch) that contribute to the pathogenesis of cancer. SCFAs block cancer stem cell proliferation, thereby potentially delaying or inhibiting cancer development or relapse by targeting genes and pathways that are mutated in tumors (e.g., epidermal growth factor receptor, hepatocyte growth factor, and MET) and by promoting the expression of tumor suppressors (e.g., by up-regulating PTEN and p53). When administered properly, SCFAs have many advantages compared to probiotic bacteria and fecal transplants. In carcinogenesis, SCFAs are toxic against tumor cells but not to surrounding tissue due to differences in their metabolic fate. Multiple hallmarks of cancer are also targets of SCFAs. These data suggest that SCFAs may re-establish homeostasis without overt toxicity and either delay or prevent the development of various tumor types.

Dynamical modeling of proliferative-invasive plasticity and IFNγ signaling in melanoma reveals mechanisms of PD-L1 expression heterogeneity

BACKGROUND

Phenotypic heterogeneity of melanoma cells contributes to drug tolerance, increased metastasis, and immune evasion in patients with progressive disease. Diverse mechanisms have been individually reported to shape extensive intra-tumor and inter-tumor phenotypic heterogeneity, such as IFNγ signaling and proliferative to invasive transition, but how their crosstalk impacts tumor progression remains largely elusive.

METHODS

Here, we integrate dynamical systems modeling with transcriptomic data analysis at bulk and single-cell levels to investigate underlying mechanisms behind phenotypic heterogeneity in melanoma and its impact on adaptation to targeted therapy and immune checkpoint inhibitors. We construct a minimal core regulatory network involving transcription factors implicated in this process and identify the multiple 'attractors' in the phenotypic landscape enabled by this network. Our model predictions about synergistic control of PD-L1 by IFNγ signaling and proliferative to invasive transition were validated experimentally in three melanoma cell lines-MALME3, SK-MEL-5 and A375.

RESULTS

We demonstrate that the emergent dynamics of our regulatory network comprising MITF, SOX10, SOX9, JUN and ZEB1 can recapitulate experimental observations about the co-existence of diverse phenotypes (proliferative, neural crest-like, invasive) and reversible cell-state transitions among them, including in response to targeted therapy and immune checkpoint inhibitors. These phenotypes have varied levels of PD-L1, driving heterogeneity in immunosuppression. This heterogeneity in PD-L1 can be aggravated by combinatorial dynamics of these regulators with IFNγ signaling. Our model predictions about changes in proliferative to invasive transition and PD-L1 levels as melanoma cells evade targeted therapy and immune checkpoint inhibitors were validated in multiple RNA-seq data sets from in vitro and in vivo experiments.

CONCLUSION

Our calibrated dynamical model offers a platform to test combinatorial therapies and provide rational avenues for the treatment of metastatic melanoma. This improved understanding of crosstalk among PD-L1 expression, proliferative to invasive transition and IFNγ signaling can be leveraged to improve the clinical management of therapy-resistant and metastatic melanoma.

PD-L1 Downregulation and DNA Methylation Inhibition for Molecular Therapy against Cancer Stem Cells in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a heterogeneous cancer characterized by various cellular subtypes. This study investigates the potential of a combination strategy using immunotherapy and epigenetic reprogramming against HCC. We used a transgenic HCC mouse C57BL/6J-TG(ALB1HBV)44BRI/J to assess the dynamics of the programmed death receptor and its ligand (PD-1/PD-L1) and DNA methylation markers. In parallel, PD-L1 RNA silencing was performed in various human HCC cell lines, while combination therapy was performed in a co-culture system using long-term exposure of 5-Azacytidine (5-AZA) and an anti-PD-L1. Data from the mouse model showed that the expressions of Pdcd1, Pdcd1l1, and DNA methyltransferase 1 (Dnmt1) were significantly higher in HCC as compared to the wild-type mice (p < 0.01), supported by the high presence of PD-L1 methylated DNA. In HCC cell lines, PD-L1 silencing was accompanied by DNMT1 reduction, mostly noted in aggressive HCC cell lines, followed by the dysregulation of the cancer stem cell marker EpCAM. In combination therapy, the growth of HCC cells and lymphocytes was limited by the PD-L1 antibody, further reduced in the presence of 5-AZA by up to 20% (p < 0.001). The data demonstrated that combination therapy might be an option as a potential treatment for heterogeneous HCC.