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

Harnessing immunotherapy for hepatocellular carcinoma: Principles and emerging promises

HCC is considered as one of the leadin causes of death worldwide, with the ability of resistance towards therapeutics. Immunotherapy, particularly ICIs, have provided siginficant insights towards harnessing the immune system. The present review introduces the concepts and possibilities of immunotherapy for HCC treatment, emphasizing its underlying mechanisms and capacity to enhance patient results, focusing on both pre-clinical and clinical insights. The functions of TME and immune evasion mechanisms typical of HCC would be evaluated along with how contemporary immunotherapeutic approaches are designed to address these challenges. Furthermore, the clinical application of immunotherapy in HCC is discussed, emphasizing recent trial findings demonstrating the effectiveness and safety of drugs. In addition, the problems caused by immune evasion and resistance would be discussed to increase potential of immunotherapy along with combination therapy.

PDZK1 inhibits MRP2-mediated oxaliplatin chemosensitivity in hepatocellular carcinoma

Recurrence after oxaliplatin chemotherapy is a major challenge in the treatment of advanced hepatocellular carcinoma patients. Differential expression gene analysis and Kaplan-Meier curves were screened biomarkers associated with OXA-treated recurrence in GSE51951, TCGA-LIHC, and Chinese Liver Cancer Atlas databases. We retrospectively collected 39 cases of HCC treated with platinum based drugs at the First Hospital of Shanxi Medical University. Immunohistochemistry was used to analyze the relationship between PDZK1 expression and patient recurrence of HCC. Cell model and subcutaneous transplant tumor model of HCC were established to detect the cell growth ability treated with OXA. Gene Set Enrichment Analysis analysis identified signaling pathways associated with high PDZK1. Co-Immunoprecipitation and immunofluorescence experiments were used to explore the potential interaction between PDZK1 and MRP2. We identified that high expression of PDZK1 was associated with OXA resistance and poor prognosis in HCC. PDZK1 promoted the cell viability, migration, and invasion of HCC after OXA treatment in vitro and vivo. MRP2-mediated ABC transporters pathway and bile acid metabolism were significantly activated in the PDZK1 overexpression group of HCC. PDZK1 interacted and co-localized with the carboxyl terminal PDZ binding motif of MRP2. Clinical specimen analysis have shown a positive correlation between the protein levels of PDZK1 and MRP2. Our study identified PDZK1 as a novel biomarker significantly associated with OXA chemosensitivity in HCC. Mechanistically, PDZK1 promoted the OXA sensitivity of HCC by activating the MRP2-mediated signaling pathway.

ID3 enhances PD-L1 expression by restructuring MYC to promote colorectal cancer immune evasion

The inhibitor of DNA binding protein ID3 has been associated with the progression of colorectal cancer (CRC). Despite its significance, its specific role in the immune evasion strategies utilized by CRC remains unclear. RNA-seq analysis revealed that ID3 was positively associated with the PD-L1 immune checkpoint. We further demonstrated that tumor cell-expressed ID3 enhanced PD-L1 expression, suppressed the infiltration and activation of CD8+ T cells, and facilitated the immune evasion of CRC cells. Additionally, we found that knockdown of ID3 significantly enhanced the effectiveness of PD-L1 antibody blockade treatment in combating CRC, reduced the upregulation of PD-L1 induced by the antibody, and altered the immune microenvironment within CRC. Mechanistically, ID3 interacted with the transcription factor MYC and reconstructed the four-dimensional structure of MYC, thereby enhancing its binding affinity to the PD-L1 promoter and augmenting PD-L1 transcriptional activity. By integrating analysis of ChIP-seq, RNA-seq, and ImmPort gene sets, we found that ID3's DNA-assisted binding function was widespread and could either enhance or suppress gene transcription, not only affecting tumor immune escape through immune checkpoints but also regulating various cytokines and immune cells involved in tumor immunity. In conclusion, our study uncovers a mechanism by which ID3 promotes immune evasion in CRC and implicates that targeting ID3 may improve the efficacy of anti-PD-1/PD-L1 immunotherapy.

The immunosuppressive role of MDSCs in HCC: mechanisms and therapeutic opportunities

Hepatocellular carcinoma (HCC) is a prevalent malignancy with a significant global burden. Despite substantial advancements in HCC treatment in recent years, therapeutic efficacy remains constrained by immune evasion mechanisms within the tumor microenvironment (TME). Myeloid-derived suppressor cells (MDSCs), as critical immunosuppressive elements of the TME, have garnered increasing attention for their role in tumor progression. Recent studies emphasize their central involvement in promoting immune evasion, tolerance, and immunosuppression in HCC. This review examines the contributions of MDSCs to HCC pathogenesis, elucidates their underlying mechanisms, and discusses ongoing clinical trials, emphasizing their potential as therapeutic targets for improving clinical outcomes.

The Recruitment and Immune Suppression Mechanisms of Myeloid-Derived Suppressor Cells and Their Impact on Bone Metastatic Cancer

BACKGROUND

MDSCs are immature neutrophils and monocytes with immunosuppressive potentials, involving mononuclear MDSCs (M-MDSCs) and polymorphonuclear MDSCs (PMN-MDSCs).

RECENT FINDINGS

They are significant components of the tumor microenvironment (TME). Besides, recent studies also verified that MDSCs also facilitated the progression of bone metastasis by regulating the network of cytokines and the function of immune cells.

CONCLUSION

It is necessary to summarize the mechanisms of MDSC recruitment and immunosuppression, and their impact on bone metastasis.

Cancer Stem Cell markers: Symphonic masters of chemoresistance and immune evasion

Cancer Stem Cells (CSCs) are highly tumorigenic, chemoresistant, and immune evasive. They emerge as a central driver that gives rise to the bulk of tumoral mass, modifies the tumor microenvironment (TME), and exploits it, leading to poor clinical outcomes for patients with cancer. The existence of CSCs thus accounts for the failure of conventional therapies and immune surveillance. Identifying CSCs in solid tumors remains a significant challenge in modern oncology, with the use of cell surface markers being the primary strategy for studying, isolating, and enriching these cells. In this review, we explore CSC markers, focusing on the underlying signaling pathways that drive CSC self-renewal, which simultaneously makes them intrinsically chemoresistant and immune system evaders. We comprehensively discuss the autonomous and non-autonomous functions of CSCs, with particular emphasis on their interactions with the tumor microenvironment, especially immune cells. This reciprocal network enhances CSCs malignancy while compromising the surrounding niche, ultimately defining therapeutic vulnerabilities associated with each CSC marker. The most common CSCs surface markers addressed in this review-CD44, CD133, ICAM1/CD54, and LGR5-provide insights into the interplay between chemoresistance and immune evasion, two critically important phenomena in disease eradication. This new perspective on the state-of-the-art of CSCs will undoubtedly open new avenues for therapy.

Enhanced interactions within microenvironment accelerates dismal prognosis in HBV-related HCC after TACE

BACKGROUND

Transarterial chemoembolization (TACE) is the first-line treatment for patients with advanced HCC, but there are limited studies on the microenvironment alterations caused by TACE.

METHODS

Six fresh HBV-related HCC specimens with or without TACE intervention were used to perform single-cell RNA sequencing. The 757 bulk samples from 3 large-scale multicenter cohorts were applied for comprehensive analysis. The biological functions of the biomarkers were further validated by phenotypic experiments.

RESULTS

Using single-cell RNA sequencing analysis, we delineated the global cell atlas of post-TACE and demonstrated elevated tumor heterogeneity and an enhanced proinflammatory microenvironment induced by TACE. Cell-cell communication analysis revealed that markedly elevated interactions between NABP1+ malignant hepatocytes, neutrophils, and CD8+ T cells after TACE might accelerate the shift from CD8+ effector memory T cells to CD8+ effector T cells. This result was substantiated by the developmental trajectory between the 2 and dramatically decreased resident scores along the pseudotemporal trajectory. Integrating bulk data, we further found that the increased estimated proportion of NABP1+ malignant hepatocytes was related to poor TACE response and dismal prognosis, and its biomarker role could be replaced by NABP1. In vitro, multiple biological experiments consistently verified that NABP1 knockdown significantly inhibited the proliferation and migration of HCC cells.

CONCLUSIONS

Based on our depicted global map of post-TACE, we confirmed that the enhanced interactions within the microenvironment after TACE may be the culprits for postoperative progression. NABP1 may become an attractive tool for the early identification of patients sensitive to first-line TACE in clinical practice.

Cancer-associated fibroblasts-derived exosomal ZNF250 promotes the proliferation, migration, invasion, and immune escape of hepatocellular carcinoma cells by transcriptionally activating PD-L1

Hepatocellular carcinoma (HCC) is a lethal form of liver cancer, and the tumor microenvironment, particularly cancer-associated fibroblasts (CAFs), plays a critical role in its progression. This study aimed to elucidate the mechanism by which CAF-derived exosomes regulate the development of HCC. The study employed quantitative real-time polymerase chain reaction for mRNA expression analysis and western blot analysis for protein expression detection. Chromatin immunoprecipitation assay and dual-luciferase reporter assay were performed to investigate the relationship between zinc finger protein 250 (ZNF250) and programmed cell death 1 ligand 1 (PD-L1). Transmission electron microscopy and western blot analysis were used to characterize the isolated exosomes. The transferability of CAF-derived exosomes and normal fibroblasts (NFs)-derived exosomes into HCC cells was analyzed using a green fluorescent labeling dye PKH67. Cell proliferation was assessed via a 5-Ethynyl-2'-deoxyuridine assay, while Transwell assays were conducted to evaluate cell migration and invasion. Flow cytometry was performed to measure cell apoptosis, while enzyme-linked immunosorbent assays were used to assess the levels of tumor necrosis factor-α and perforin. Finally, a xenograft mouse model was constructed to examine the effects of exosomes derived from ZNF250-deficient CAFs on the tumor properties of HCC cells. The study revealed increased expression of ZNF250 in HCC tissues and cells, with ZNF250 transcriptionally activating PD-L1 in HCC cells. ZNF250 expression was associated with HbsAg, clinical stage and tumor size of HCC patients. CAF-derived exosomal ZNF250 can regulate PD-L1 expression in HCC cells. Furthermore, exosomes derived from ZNF250-deficient CAFs inhibited the proliferation, migration, invasion, and immune escape of HCC cells by downregulating PD-L1 expression. Moreover, CAF-derived exosomal ZNF250 promoted tumor formation in vivo. These findings provide insights into the role of CAF-derived exosomes in the suppression of HCC development, highlighting the significance of ZNF250 and PD-L1 regulation in tumor progression.

Advances in hepatocellular carcinoma drug resistance models

Hepatocellular carcinoma (HCC) is the most common primary liver cancer. Surgery has been the major treatment method for HCC owing to HCC's poor sensitivity to radiotherapy and chemotherapy. However, its effectiveness is limited by postoperative tumour recurrence and metastasis. Systemic therapy is applied to eliminate postoperative residual tumour cells and improve the survival of patients with advanced HCC. Recently, the emergence of various novel targeted and immunotherapeutic drugs has significantly improved the prognosis of advanced HCC. However, targeted and immunological therapies may not always produce complete and long-lasting anti-tumour responses because of tumour heterogeneity and drug resistance. Traditional and patient-derived cell lines or animal models are used to investigate the drug resistance mechanisms of HCC and identify drugs that could reverse the resistance. This study comprehensively reviewed the established methods and applications of in-vivo and in-vitro HCC drug resistance models to further understand the resistance mechanisms in HCC treatment and provide a model basis for possible individualised therapy.

DDR2/STAT3 Positive Feedback Loop Mediates the Immunosuppressive Microenvironment by Upregulating PD-L1 and Recruiting MDSCs in Oxaliplatin-Resistant HCC

BACKGROUND AND AIMS

Transcriptome sequencing revealed high expression of DDR2 in oxaliplatin-resistant hepatocellular carcinoma (HCC). This study aimed to explore the role of DDR2 in oxaliplatin resistance and immune evasion in HCC.

METHODS

Oxaliplatin-resistant HCC cell lines were established. The interaction between DDR2 and STAT3 was investigated, along with the mechanisms involved in DDR2/STAT3-mediated PD-L1 upregulation and polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) accumulation both in vitro and in vivo.

RESULTS

DDR2 was found to induce the phosphorylation of STAT3, leading to its nuclear translocation. Conversely, the activation of STAT3 enhanced DDR2 expression. A positive feedback loop involving DDR2/STAT3 was identified in oxaliplatin-resistant HCC, which was associated with PD-L1 upregulation and PMN-MDSCs accumulation. Knockdown of DDR2 and STAT3 sensitized oxaliplatin-resistant HCC cells to oxaliplatin and resulted in decreased PMN-MDSCs and increased CD8+ T cells in the tumor microenvironment. Enzyme-linked immunosorbent array and MDSC transwell migration assays indicated that oxaliplatin-resistant HCC cells recruited PMN-MDSCs through CCL20. Dual luciferase reporter assays demonstrated that STAT3 can directly enhance the transcription of PD-L1 and CCL20. Furthermore, treatment with a PD-L1 antibody in combination with CCL20 blockade had significant antitumor effects on oxaliplatin-resistant HCC.

CONCLUSIONS

Our findings revealed a positive feedback mechanism involving DDR2 and STAT3 that mediates the immunosuppressive microenvironment and promotes oxaliplatin resistance and immune evasion via PD-L1 upregulation and PMN-MDSC recruitment. Targeting the DDR2/STAT3 pathway may be a promising therapeutic strategy to overcome immune escape and chemoresistance in HCC.

Multifunctional and stimuli-responsive liposomes in hepatocellular carcinoma diagnosis and therapy

Hepatocellular carcinoma (HCC) is the most prevalent type of liver cancer, mainly occurring in Asian countries with an increased incidence rate globally. Currently, several kinds of therapies have been deployed for HCC therapy including surgical resection, chemotherapy, radiotherapy and immunotherapy. However, this tumor is still incurable, requiring novel strategies for its treatment. The nanomedicine has provided the new insights regarding the treatment of cancer that liposomes as lipid-based nanoparticles, have been widely applied in cancer therapy due to their biocompaitiblity, high drug loading and ease of synthesis and modification. The current review evaluates the application of liposomes for the HCC therapy. The drugs and genes lack targeting ability into tumor tissues and cells. Therefore, loading drugs or genes on liposomes can increase their accumulation in tumor site for HCC suppression. Moreover, the stimuli-responsive liposomes including pH-, redox- and light-sensitive liposomes are able to deliver drug into tumor microenvironment to improve therapeutic index. Since a number of receptors upregulate on HCC cells, the functionalization of liposomes with lactoferrin and peptides can promote the targeting ability towards HCC cells. Moreover, phototherapy can be induced by liposomes through loading phtoosensitizers to stimulate photothermal- and photodynamic-driven ablation of HCC cells. Overall, the findings are in line with the fact that liposomes are promising nanocarriers for the treatment of HCC.

The roles of cancer stem cell-derived secretory factors in shaping the immunosuppressive tumor microenvironment in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies worldwide and has a poor prognosis. Although immune checkpoint inhibitors have entered a new era of HCC treatment, their response rates are modest, which can be attributed to the immunosuppressive tumor microenvironment within HCC tumors. Accumulating evidence has shown that tumor growth is fueled by cancer stem cells (CSCs), which contribute to therapeutic resistance to the above treatments. Given that CSCs can regulate cellular and physical factors within the tumor niche by secreting various soluble factors in a paracrine manner, there have been increasing efforts toward understanding the roles of CSC-derived secretory factors in creating an immunosuppressive tumor microenvironment. In this review, we provide an update on how these secretory factors, including growth factors, cytokines, chemokines, and exosomes, contribute to the immunosuppressive TME, which leads to immune resistance. In addition, we present current therapeutic strategies targeting CSC-derived secretory factors and describe future perspectives. In summary, a better understanding of CSC biology in the TME provides a rational therapeutic basis for combination therapy with ICIs for effective HCC treatment.

Myeloid-Derived Suppressor Cells: Therapeutic Target for Gastrointestinal Cancers

Gastrointestinal cancers represent one of the more challenging cancers to treat. Current strategies to cure and control gastrointestinal (GI) cancers like surgery, radiation, chemotherapy, and immunotherapy have met with limited success, and research has turned towards further characterizing the tumor microenvironment to develop novel therapeutics. Myeloid-derived suppressor cells (MDSCs) have emerged as crucial drivers of pathogenesis and progression within the tumor microenvironment in GI malignancies. Many MDSCs clinical targets have been defined in preclinical models, that potentially play an integral role in blocking recruitment and expansion, promoting MDSC differentiation into mature myeloid cells, depleting existing MDSCs, altering MDSC metabolic pathways, and directly inhibiting MDSC function. This review article analyzes the role of MDSCs in GI cancers as viable therapeutic targets for gastrointestinal malignancies and reviews the existing clinical trial landscape of recently completed and ongoing clinical studies testing novel therapeutics in GI cancers.

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

The application of immunotherapy in tumor, especially immune checkpoint inhibitors (ICIs), has played an important role in the treatment of advanced unresectable liver cancer. However, the efficacy of ICIs varies greatly among different patients, which has aroused people's attention to the regulatory mechanism of programmed death ligand-1 (PD-L1) in the immune escape of liver cancer. PD-L1 is regulated by multiple levels and signaling pathways in hepatocellular carcinoma (HCC), including gene variation, epigenetic inheritance, transcriptional regulation, post-transcriptional regulation, and post-translational modification. More studies have also found that the high expression of PD-L1 may be the main factor affecting the immunotherapy of liver cancer. However, what is the difference of PD-L1 expressed by different types of cells in the microenvironment of HCC, and which type of cells expressed PD-L1 determines the effect of tumor immunotherapy remains unclear. Therefore, clarifying the regulatory mechanism of PD-L1 in liver cancer can provide more basis for liver cancer immunotherapy and combined immune treatment strategy. In addition to its well-known role in immune regulation, PD-L1 also plays a role in regulating cancer cell proliferation and promoting drug resistance of tumor cells, which will be reviewed in this paper. In addition, we also summarized the natural products and drugs that regulated the expression of PD-L1 in HCC.

NLRP3/IL-1β induced myeloid-derived suppressor cells recruitment and PD-L1 upregulation promotes oxaliplatin resistance of hepatocellular carcinoma

Oxaliplatin is commonly used as the first-line chemotherapeutic agent for advanced hepatocellular carcinoma (HCC). Unfortunately, the acquired resistance, limits the effectiveness of oxaliplatin and the underlying mechanisms remain unknown. Therefore, we explored the role of NOD-like receptor protein 3 (NLRP3)/IL-1β in mediating oxaliplatin resistance in HCC. We observed that NLRP3/IL-1β expression was much higher in oxaliplatin-resistant HCC cells. To further understand its impact on drug resistance, we knocked down NLRP3 and observed that it sensitized HCC cells to the growth-inhibitory effects of oxaliplatin and induced cell apoptosis. NLRP3/IL-1β overexpressing tumor cells also attracted polymorphonuclear myeloid-derived suppressor cells. Using mouse models, we demonstrated that NLRP3/IL-1β inhibition by short hairpin RNA or MCC950 effectively overcame oxaliplatin resistance. Furthermore, NLRP3/IL-1β inhibition resulted in reduced expression of PD-L1. We also found that PD-L1 antibody combined with NLRP3/IL-1β blockade displayed significant antitumor effect in HCC. Overall, our study provides compelling evidence supporting the essential role of NLRP3/IL-1β in conferring resistance to oxaliplatin and reshaping the immunosuppressive microenvironment in HCC. Targeting NLRP3/IL-1β presents a potential therapeutic target for overcoming oxaliplatin resistance and reshaping microenvironment of HCC.