The current status and future of PD-L1 in liver cancer

Sodium butyrate increases USP5-mediated ubiquitination degradation of GPX4 and enhances anti-cancer efficacy of anti-PD-1 antibody

Hepatocellular carcinoma (HCC), a prevalent malignancy associated with a dismal prognosis, necessitates the urgent exploration of novel therapeutic avenues. Ferroptosis, an iron-mediated, lipid peroxidation-induced form of regulated cell death (RCD), has emerged as a promising target for cancer therapy. Sodium butyrate (NaBu), a short-chain fatty acid sodium salt, has demonstrated antitumor efficacy against diverse cancers, yet its specific role and mechanisms in HCC treatment remain elusive. Our findings reveal that NaBu not only impedes HCC cell growth and epithelial-mesenchymal transition (EMT) but also triggers ferroptosis by enhancing Fe2+ accumulation, reactive oxygen species (ROS) generation, and malondialdehyde (MDA) production. Notably, these effects are effectively mitigated by Ferrostatin-1 (Fer-1), underscoring the ferroptosis-inducing capacity of NaBu. Mechanistically, NaBu exerts its action by diminishing the level of ubiquitin-specific protease 5 (USP5), which subsequently leads to the ubiquitination and destabilization of glutathione peroxidase 4 (GPX4), a crucial suppressor in ferroptosis. In a preclinical setting, NaBu significantly inhibits tumor xenograft growth in nude mice, highlighting its in vivo efficacy. When paired with an anti-programmed death 1 (PD-1) antibody, NaBu exhibits a potent synergistic antitumor effect, suggesting a potential role in enhancing immunotherapy response. Collectively, our results underscore the potential of NaBu as a novel therapeutic agent for HCC, through its ability to inhibit USP5 and indirectly downregulate GPX4, thereby stimulating ferroptosis.

Mechanical mechanics-reclaiming a new battlefield for chronic liver disease

BACKGROUND

In the 21st century, significant breakthroughs have been made in the research of chronic liver disease. New biochemical markers of pathogenicity and corresponding drugs continue to emerge. However, current treatment strategies remain unsatisfactory due to complex pathological changes in the liver, including vascular dysfunction, myofibroblast-like transition, and local tissue necrosis in liver sinusoids. These challenges have created an urgent need for innovative, synergistic treatments. Mechanical mechanics is a growing field, with increasing evidence suggesting that mechanical signals play a role similar to that of biochemical markers. These signals influence response speed, conduction intensity, and functional diversity in regulating cell activities.

AIM OF REVIEW

This review summarizes the three main mechanical characteristics involved in the progression of "liver fibrosis-cirrhosis-hepatocellular carcinoma" and provides an in-depth interpretation of several mechanically-related targets. Finally, current and cutting-edge therapeutic strategies are proposed from a cellular perspective. Despite the many challenges that remain, this review is both relevant and significant.

Radiosynthesis and Evaluation of a Novel 68Ga-Labeled Peptide for PD-L1-Targeted PET Imaging

Although programmed death-ligand 1 (PD-L1)-targeted immunotherapy has demonstrated favorable therapeutic effects, concern regarding a low response rate persists. Our study aimed to develop a novel peptide probe for PD-L1 targeting positron emission tomography (PET)/computed tomography (CT) imaging as an alternative for assessing PD-L1 expression and exploring its potential role in guiding PD-L1 immunotherapy in vivo. The probe targeting PD-L1 was obtained by modifying 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) with the peptide CCC, followed by labeling with 68Ga. Radiochemical purity, log P, pharmacokinetics, and stability of the probe were evaluated in vitro and in vivo. The systematic evaluation of the probe performance included microPET/CT imaging, biodistribution, biosafety, and an investigation of its use in immunotherapy monitoring. 68Ga-DOTA-CCC was successfully synthesized with over 99% radiochemical purity, eliminating the need for purification. The probe exhibited good hydrophilicity and stability and was rapidly metabolized with a short blood clearance half-life of 16.1 ± 0.5 min. Additionally, the probe exhibited an excellent PD-L1 targeting ability, with tumor uptake positively correlating with PD-L1 expression levels in both cellular experiments and microPET/CT imaging. Moreover, the dynamic expression of PD-L1 was assessed using 68Ga-DOTA-CCC during atezolizumab administration. 68Ga-DOTA-CCC accurately reflects PD-L1 expression and holds promise for precisely guiding PD-L1-targeted immunotherapy.

Unveiling the nexus of p53 and PD-L1: insights into immunotherapy resistance mechanisms in hepatocellular carcinoma

Hepatocellular carcinoma (HCC), the predominant form of primary liver cancer worldwide, continues to pose a substantial health challenge with limited treatment options for advanced stages. Despite progress in therapies such as surgery, transplantation, and targeted treatments, prognosis remains bleak for many patients. The advent of immunotherapy has revolutionized the landscape of advanced HCC treatment, offering hope for improved outcomes. However, its efficacy is limited, with a modest response rate of approximately 20% as a single-agent therapy, underscoring the urgent need to decipher mechanisms of immunotherapy resistance. Tumor protein 53 gene (TP53), a pivotal tumor suppressor gene, and Programmed death ligand 1 (PD-L1), a crucial immune checkpoint ligand, play central roles in HCC's evasion of immune responses. Understanding how tumor protein 53 (p53) influences PD-L1 expression and immune system interactions is essential for unraveling the complexities of immunotherapy resistance mechanisms. Elucidating these molecular interactions not only enhances our understanding of HCC's underlying mechanisms but also lays the foundation for developing targeted treatments that may improve outcomes for patients with advanced-stage liver cancer. Ultimately, deciphering the nexus of p53 and PD-L1 in immunotherapy resistance promises to advance treatment strategies and outcomes in the challenging landscape of HCC. This review delves into the intricate relationship between p53 and PD-L1 concerning immunotherapy resistance in HCC, offering insights that could pave the way for novel therapeutic strategies aimed at enhancing treatment efficacy and overcoming resistance in advanced stages of the disease.

Melatonin suppresses PD-L1 expression and exerts antitumor activity in hepatocellular carcinoma

Melatonin, also known as the pineal hormone, is secreted by the pineal gland and primarily regulates circadian rhythms. Additionally, it possesses immunomodulatory properties and anticancer effects. However, its specific mechanism in hepatocellular carcinoma (HCC) remains unclear, particularly regarding its effect on HCC-mediated immune escape through PD-L1 expression.In this study, in vitro experiments were conducted using Huh7 and HepG2 HCC cells. Melatonin treatment was applied to both cell types to observe changes in malignant phenotypes. Additionally, melatonin-pretreated Huh7 or HepG2 cells were co-cultured with T cells to simulate the tumor microenvironment. The results showed that melatonin inhibited cancer cell proliferation, migration, and invasion, as well as reduced PD-L1 expression in cancer cells, exhibiting similar anti-cancer effects in the co-culture system. In vivo experiments involved establishing ascitic HCC mouse models using H22 cells, followed by subcutaneous tumor models in Balb/c nude and Balb/c wild-type mice. Melatonin inhibited tumor growth and suppressed PD-L1 expression in cancer tissues in both subcutaneous tumor models, and it increased T lymphocyte activity in the spleen of Balb/c wild-type mice. Overall, the in vitro and in vivo experiments demonstrated that melatonin has dual anti-cancer effects in HCC: direct intrinsic anti-cancer activity and enhancement of anti-tumor immunity by reducing PD-L1 expression thereby inhibiting cancer immune escape. Furthermore, a decrease in the expression of the upstream molecule HIF-1α of PD-L1 and an increase in the expression levels of JNK, P38, and their phosphorylated forms were detected. Thus, the mechanism by which melatonin reduces PD-L1 may involve the downregulation of HIF-1α expression or the activation of the MAPK-JNK and MAPK-P38 pathways. This provides new insights and strategies for HCC treatment.

A novel phosphodiesterase target as a therapeutic approach: inhibiting DEN-induced hepatocellular carcinoma progression

Hepatocellular Carcinoma (HCC) is one of the most common and fatal types of liver cancer worldwide; in this sense, Diethylnitrosamine (DEN) has been established as a potent carcinogen affecting the development and progression of this disease. The present work focused on determining whether phosphodiesterase (PDE) enzymes, especially PDE5, may serve as targets in the therapeutic treatment of DEN-induced HCC. PDE5 inhibitors, widely used as therapeutic drugs for cardiovascular diseases and erectile dysfunction, have recently been found to be promising in preclinical cancer models through the modulation of key signaling pathways implicated in the progression of tumors, such as the cGMP-PKG, JNK, and MAPK pathways. These pathways are very important for cell proliferation, apoptosis and metastasis, and their dysregulation contributes to the aggressive nature of HCC. This study assessed the potential of PDE5 inhibitors to suppress proliferation, induce apoptosis, and alter the tumor microenvironment, thus potentially improving standard chemotherapy and immunotherapy interventions. By inhibiting certain PDE isoforms with these drugs, an anticancer response might occur as part of a complex mechanism that acts on both cancer cells and the microenvironment favorable for tumor growth. A preliminary review indicated that PDE inhibitors may be a promising therapeutic approach for overcoming some of the shortcomings of current treatments, particularly the development of resistance and the toxic effects of these treatments. Additional clinical investigations are necessary to determine the safety profile, appropriate amount of Osage, and long-term efficacy of these agents in the treatment of HCC, particularly in DEN-induced animal models. This study contributes to the expanding body of evidence supporting the use of PDE inhibitors in cancer treatment.

Role of Artificial Intelligence in Identifying Vital Biomarkers with Greater Precision in Emergency Departments During Emerging Pandemics

The COVID-19 pandemic has accelerated advances in molecular biology and virology, enabling the identification of key biomarkers to differentiate between severe and mild cases. Furthermore, the use of artificial intelligence (AI) and machine learning (ML) to analyze large datasets has been crucial for rapidly identifying relevant biomarkers for disease prognosis, including COVID-19. This approach enhances diagnostics in emergency settings, allowing for more accurate and efficient patient management. This study demonstrates how machine learning algorithms in emergency departments can rapidly identify key biomarkers for the vital prognosis in an emerging pandemic using COVID-19 as an example by analyzing clinical, epidemiological, analytical, and radiological data. All consecutively admitted patients were included, and more than 89 variables were processed using the Random Forest (RF) algorithm. The RF model achieved the highest balanced accuracy at 92.61%. The biomarkers most predictive of mortality included procalcitonin (PCT), lactate dehydrogenase (LDH), and C-reactive protein (CRP). Additionally, the system highlighted the significance of interstitial infiltrates in chest X-rays and D-dimer levels. Our results demonstrate that RF is crucial in identifying critical biomarkers in emerging diseases, accelerating data analysis, and optimizing prognosis and personalized treatment, emphasizing the importance of PCT and LDH in high-risk patients.

The immunotherapy mechanism of Hedyotis Diffusae Herba in treating liver cancer: a study based on network pharmacology, bioinformatics, and experimental validation

Liver cancer is a malignant tumor that develops on or inside the liver. Hedyotis diffusa Willd (HDW) plays a significant role in anti-tumor activities; however, its mechanism against liver cancer remains unclear. This study aims to evaluate the immunotherapeutic mechanism of HDW in treating liver cancer through network pharmacology, bioinformatics analysis, and experimental validation. Network pharmacology was utilized to identify the active components and potential targets of HDW from the TCMSP database. A potential target protein-protein interaction (PPI) network was constructed using the STRING database, followed by function and pathway enrichment analysis of the targets using GO and KEGG methods. In addition, the key targets for HDW against liver cancer were identified using five different algorithms in Cytoscape. The TCGA and HPA databases were used to assess the mRNA and protein expression of core target genes in normal liver and liver cancer tissues and their relationship with overall survival in liver cancer, as well as their role in immune infiltration. Molecular docking between the core components of HDW and the core targets was performed using PyMOL software. The effects of HDW on the proliferation and apoptosis of liver cancer cells were examined using MTT and flow cytometry. The regulatory effects of the core component quercetin on core targets were validated using RT-qPCR and Western blot. A total of 163 potential targets were identified by searching for intersections among 7 types of active components and all potential and liver cancer targets. PPI network analysis revealed the core targets IL6 and TNF. GO enrichment analysis involved 2089 biological processes, 76 cellular components, and 196 molecular functions. KEGG enrichment analysis suggested that the anti-cancer effects of HDW might be mediated by the AGE-RAGE signaling pathway, IL-17 signaling pathway, TNF signaling pathway, PI3K-Akt signaling pathway, and NF-κB signaling pathway. Database validation of key targets showed that mRNA and protein expression results for the IL6 gene were contradictory, while those for the TNF gene were consistent, both being underexpressed in liver cancer. Importantly, the expression of IL6 and TNF was related to the infiltration of 24 types of immune cells, with the highest correlation with macrophages. Molecular docking showed that IL6 and TNF had high binding stability with quercetin, with binding energies of - 7.4 and - 6.0 kJ∙mol-1, respectively. Experimental validation showed that quercetin inhibited liver cancer cell proliferation and promoted apoptosis in a dose-dependent manner, with protein results indicating that quercetin downregulated the mRNA and protein expression of IL6 and TNF, and upregulated key proteins in the AGE-RAGE signaling pathway, AGEs, and RAGE. This study comprehensively elucidates the activity, potential targets, and molecular mechanisms of HDW against liver cancer, providing a promising strategy for the scientific basis and treatment mechanism of traditional Chinese medicine in treating liver cancer.

ABCA1 promote tumor environment heterogeneity via epithelial mesenchymal transition in Huh7 and HepG2 liver cancer cell

In this study, we delve into the intrinsic mechanisms of cell communication in hepatocellular carcinoma (HCC). Initially, employing single-cell sequencing, we analyze multiple malignant cell subpopulations and cancer-associated fibroblast (CAF) subpopulations, revealing their interplay through receptor-ligand interactions, with a particular focus on SPP1. Subsequently, employing unsupervised clustering analysis, we delineate two clusters, C1 and C2, and compare their infiltration characteristics using various tools and metrics, uncovering heightened cytotoxicity and overall invasion abundance in C1. Furthermore, our gene risk scoring model indicates heightened activity of the immune therapeutic pathway in C1. Lastly, employing a formulated scoring system, we stratify patients into high and low-risk groups, revealing notably poorer outcomes in the high-risk cohort on Kaplan-Meier curves. Risk scores exhibit a negative correlation with model genes and immune cell infiltration scores, indicating poor prognosis in the high-risk group. Further characterization elucidates the regulatory landscape of the high and low-risk groups across various signaling pathways. In addition, we used wet lab experiments to prove that ABCA1 plays a pro-oncogenic role in hepatocellular carcinoma cells by promoting proliferation, invasion, migration, and reducing apoptosis. In summary, these findings provide crucial insights, offering valuable clues and references for understanding HCC pathogenesis and patient prognosis.

Notch Signaling and PD-1/PD-L1 Interaction in Hepatocellular Carcinoma: Potentialities of Combined Therapies

Immunotherapy has shown significant improvement in the survival of patients with hepatocellular carcinoma (HCC) compared to TKIs as first-line treatment. Unfortunately, approximately 30% of HCC exhibits intrinsic resistance to ICIs, making new therapeutic combinations urgently needed. The dysregulation of the Notch signaling pathway observed in HCC can affect immune cell response, reducing the efficacy of cancer immunotherapy. Here, we provide an overview of how Notch signaling regulates immune responses and present the therapeutic rationale for combining Notch signaling inhibition with ICIs to improve HCC treatment. Moreover, we propose using exosomes as non-invasive tools to assess Notch signaling activation in hepatic cancer cells, enabling accurate stratification of patients who can benefit from combined strategies.

Therapeutic Potential of lncRNAs in Regulating Disulfidptosis for Cancer Treatment

Non-coding RNAs (lncRNAs) play critical roles in various cellular processes, including a novel form of regulated cell death known as disulfidptosis, characterized by accumulating protein disulfide bonds and severe endoplasmic reticulum stress. This review highlights the therapeutic potential of lncRNAs in regulating disulfidptosis for cancer treatment, emphasizing their influence on key pathway components such as GPX4, SLC7A11, and PDIA family members. Recent studies have demonstrated that targeting specific lncRNAs can sensitize cancer cells to disulfidptosis, offering a promising approach to cancer therapy. The regulation of disulfidptosis by lncRNAs involves various signaling pathways, including oxidative stress, ER stress, and calcium signaling. This review also discusses the molecular mechanisms underlying lncRNA regulation of disulfidptosis, the challenges of developing lncRNA-based therapies, and the future potential of this rapidly advancing field in cancer research.

Targeting the p53-p21 axis in liver cancer: Linking cellular senescence to tumor suppression and progression

Liver cancer is a major health epidemic worldwide, mainly due to its high mortality rates and limited treatment options. The association of cellular senescence to tumorigenesis and the cancer hallmarks remains a subject of interest in cancer biology. The p53-p21 signalling axis is an important regulator in restoring the cell's balance by supporting tumor suppression and tumorigenesis in liver cancer. We review the novel molecular mechanisms that p53 and its downstream effector, p21, employ to induce cellular senescence, making it last longer, and halt the proliferation of damaged hepatocytes to become tumorous cells. We also examine how dysregulation of this pathway contributes to HCC pathogenesis, proliferation, survival, acquired resistance to apoptosis, and increased invasiveness. Furthermore, we comprehensively describe the molecular cross-talk between the p53-p21 signalling axis and major cell cycle signalling pathways, including Wnt/β-catenin, PI3K/Akt, and TGF-β in liver cancer and provide an overview of promising candidates for chemoprevention and future therapeutic strategies. This review article explores the roles of the p53-p21 pathway in liver cancer, examining its function in promoting cellular senescence under normal conditions and its potential role in cancer progression. It also highlights novel therapeutic drugs and drug targets within the pathway and discusses the implications for treatment strategies and prognosis in liver cancer.

Resistance against the development of diethylnitrosamine-induced hepatocellular carcinoma in female C3H mice: an experimental model

Histopathological features of hepatocellular carcinoma (HCC) induced by diethylnitrosamine (DEN) in mice display strong similarities with those seen in humans, including the higher tumor prevalence in males than in females. Previous studies have demonstrated that continual production of the pro-inflammatory IL-6 by Kupffer cells is involved in the initiation and progression of DEN-induced HCC and that estrogen-mediated reduction of IL-6 secretion would decrease its incidence in females. Given the predominant utilization of male mice in hepatic carcinogenesis research, the objective of this study was to examine histopathological and immunological parameters in the DEN-induced liver carcinogenesis model in female C3H mice. We observed a significant prevalence of hepatocellular hyperplasias and adenomas alongside a minimal infiltration of inflammatory cells and a scarcity of senescent areas in females. Further, a low expression of immunosuppression markers is observed in females - such as neutrophil/lymphocyte ratio, PD-1 expression in CD8 T cells, and PD-L1 in myeloid cells - compared to males. Comparative studies between susceptible and resistant hosts to chemical carcinogenesis may help to unveil novel therapeutic strategies against cancer.

The role of exosomes in liver cancer: comprehensive insights from biological function to therapeutic applications

In recent years, cancer, especially primary liver cancer (including hepatocellular carcinoma and intrahepatic cholangiocarcinoma), has posed a serious threat to human health. In the field of liver cancer, exosomes play an important role in liver cancer initiation, metastasis and interaction with the tumor microenvironment. Exosomes are a class of nanoscale extracellular vesicles (EVs)secreted by most cells and rich in bioactive molecules, including RNA, proteins and lipids, that mediate intercellular communication during physiological and pathological processes. This review reviews the multiple roles of exosomes in liver cancer, including the initiation, progression, and metastasis of liver cancer, as well as their effects on angiogenesis, epithelial-mesenchymal transformation (EMT), immune evasion, and drug resistance. Exosomes have great potential as biomarkers for liver cancer diagnosis and prognosis because they carry specific molecular markers that facilitate early detection and evaluation of treatment outcomes. In addition, exosomes, as a new type of drug delivery vector, have unique advantages in the targeted therapy of liver cancer and provide a new strategy for the treatment of liver cancer. The challenges and prospects of exosome-based immunotherapy in the treatment of liver cancer were also discussed. However, challenges such as the standardization of isolation techniques and the scalability of therapeutic applications remain significant hurdles.

Progress of immune checkpoint inhibitors in the treatment of advanced hepatocellular carcinoma

Among primary liver cancers, hepatocellular carcinoma is the most common pathological type. Its onset is insidious, and most patients have no obvious discomfort in the early stage, so it is found late, and the opportunity for surgical radical treatment is lost, resulting in a poor prognosis. With the introduction of molecular-targeted drugs represented by sorafenib, patients with middle- and late-stage liver cancer have regained the light of day. However, their therapeutic efficacy is relatively low due to the limited target of drug action, toxic side effects, and other reasons. At this time, the emergence of immunotherapy represented by immune checkpoint inhibitors (ICIs) well breaks this embarrassing situation, which mainly achieves the anti-tumor purpose by improving the tumor immune microenvironment. Currently, ICI monotherapy, as well as combination therapy, has been widely used in the clinic, further prolonging the survival of patients with advanced hepatocellular carcinoma. This article reviews the development of monotherapy and combination therapy for ICIs in advanced hepatocellular carcinoma and the latest research progress.

Intricate effects of post-translational modifications in liver cancer: mechanisms to clinical applications

Liver cancer is a significant global health challenge, with hepatocellular carcinoma (HCC) being the most prevalent form, characterized by high incidence and mortality rates. Despite advances in targeted therapies and immunotherapies, the prognosis for advanced liver cancer remains poor. This underscores the urgent need for a deeper understanding of the molecular mechanisms underlying HCC to enable early detection and the development of novel therapeutic strategies. Post-translational modifications (PTMs) are crucial regulatory mechanisms in cellular biology, affecting protein functionality, interactions, and localization. These modifications, including phosphorylation, acetylation, methylation, ubiquitination, and glycosylation, occur after protein synthesis and play vital roles in various cellular processes. Recent advances in proteomics and molecular biology have highlighted the complex networks of PTMs, emphasizing their critical role in maintaining cellular homeostasis and disease pathogenesis. Dysregulation of PTMs has been associated with several malignant cellular processes in HCC, such as altered cell proliferation, migration, immune evasion, and metabolic reprogramming, contributing to tumor growth and metastasis. This review aims to provide a comprehensive understanding of the pathological mechanisms and clinical implications of various PTMs in liver cancer. By exploring the multifaceted interactions of PTMs and their impact on liver cancer progression, we highlight the potential of PTMs as biomarkers and therapeutic targets. The significance of this review lies in its potential to inform the development of novel therapeutic approaches and improve prognostic tools for early intervention in the fight against liver cancer.