Immune Checkpoint FGL1 Expression of Circulating Tumor Cells Is Associated With Poor Survival in Curatively Resected Hepatocellular Carcinoma

FGL1 and FGL2: emerging regulators of liver health and disease

Liver disease is a complex group of diseases with high morbidity and mortality rates, emerging as a major global health concern. Recent studies have highlighted the involvement of fibrinogen-like proteins, specifically fibrinogen-like protein 1 (FGL1) and fibrinogen-like protein 2 (FGL2), in the regulation of various liver diseases. FGL1 plays a crucial role in promoting hepatocyte growth, regulating lipid metabolism, and influencing the tumor microenvironment (TME), contributing significantly to liver repair, non-alcoholic fatty liver disease (NAFLD), and liver cancer. On the other hand, FGL2 is a multifunctional protein known for its role in modulating prothrombin activity and inducing immune tolerance, impacting viral hepatitis, liver fibrosis, hepatocellular carcinoma (HCC), and liver transplantation. Understanding the functions and mechanisms of fibrinogen-like proteins is essential for the development of effective therapeutic approaches for liver diseases. Additionally, FGL1 has demonstrated potential as a disease biomarker in radiation and drug-induced liver injury as well as HCC, while FGL2 shows promise as a biomarker in viral hepatitis and liver transplantation. The expression levels of these molecules offer exciting prospects for disease assessment. This review provides an overview of the structure and roles of FGL1 and FGL2 in different liver conditions, emphasizing the intricate molecular regulatory processes and advancements in targeted therapies. Furthermore, it explores the potential benefits and challenges of targeting FGL1 and FGL2 for liver disease treatment and the prospects of fibrinogen-like proteins as biomarkers for liver disease, offering insights for future research in this field.

Survival mechanisms of circulating tumor cells and their implications for cancer treatment

Metastasis remains the principal trigger for relapse and mortality across diverse cancer types. Circulating tumor cells (CTCs), which originate from the primary tumor or its metastatic sites, traverse the vascular system, serving as precursors in cancer recurrence and metastasis. Nevertheless, before CTCs can establish themselves in the distant parenchyma, they must overcome significant challenges present within the circulatory system, including hydrodynamic shear stress (HSS), oxidative damage, anoikis, and immune surveillance. Recently, there has been a growing body of compelling evidence suggesting that a specific subset of CTCs can persist within the bloodstream, but the precise mechanisms of their survival remain largely elusive. This review aims to present an outline of the survival challenges encountered by CTCs and to summarize the recent advancements in understanding the underlying survival mechanisms, suggesting their implications for cancer treatment.

Increased FGL1 Expression Predicts Poor Prognosis and Promotes EMT in Head and Neck Squamous Cell Carcinoma

Fibrinogen-like protein 1 (FGL1) is a proliferation- and metabolism-related factor secreted by the liver that is aberrantly expressed and functionally abnormal in human malignancies. However, the role of FGL1 in head and neck squamous cell carcinoma (HNSCC) remains unknown. We analysed FGL1 expression in HNSCC and its impact on patient survival using the TCGA database. The role of FGL1 in HNSCC cells was investigated by Cell Counting Kit-8, colony formation, and Transwell assays. In addition, we conducted in vivo experiments to assess the effect of FGL1 knockdown on tumour growth. We found that FGL1 was highly expressed in HNSCC and correlated with a poor prognosis. Downregulation of FGL1 expression inhibited the proliferation and invasion of HNSCC cells. Furthermore, mechanistic analysis revealed that FGL1 induced an epithelial-mesenchymal transition (EMT) phenotype and, thus, the malignant progression of HNSCC cells. Finally, xenograft models showed that FGL1 knockdown significantly inhibited EMT in HNSCC in vivo. Our study revealed that FGL1, an oncogene, promotes the malignant progression of HNSCC, providing new perspective on and potential therapeutic target for the treatment of HNSCC.

Norcantharidin potentiates sorafenib antitumor activity in hepatocellular carcinoma rat model through inhibiting IL-6/STAT3 pathway

In hepatocellular carcinoma (HCC), sorafenib (Sora) efficacy is limited by primary and/or acquired resistance. Emerging evidence shows that the inflammatory factor interleukin 6 (IL-6) plays a role in Sora resistance. Norcantharidin (NCTD), a derivative of cantharidine, was identified as a potent IL-6 inhibitor. Thus, in this study, we evaluated NCTD ability to improve the Sora efficacy in HCC and its underlying molecular mechanisms. Male Sprague Dawely rats were administered NCTD (0.1 mg/kg/day; orally) or Sora (10 mg/kg day; orally) or combination for 6 weeks after HCC induction using thioacetamide (200 mg/kg; ip; 2 times/wk) for 16 weeks. Our results showed that NCTD greatly enhanced Sora activity against HCC and potentiated Sora-induced oxidative stress. NCTD enhanced Sora-induced tumor immunity reactivation by decreasing both fibrinogen-like protein 1 level and increasing both tumor necrosis factor-α gene expression along with CD8+ T cells number. Also, NCTD augmented Sora attenuation activity against TAA-induced angiogenesis and metastasis by decreasing VEGFA, HIF-1α, serum lactate dehydrogenase enzyme, and vimentin levels. The combined use of NCTD/Sora suppressed drug resistance and stemness by downregulating ATP-binding cassette subfamily G member 2, neurogenic locus notch homolog protein, spalt-like transcription factor 4, and CD133. NCTD boosted Sora antiproliferative and apoptotic activities by decreasing Ccnd1 and BCL2 expressions along with increasing BAX and caspase-3 expressions. To our knowledge, this study represents the first study providing evidence for the potential novel therapeutic use of NCTD/Sora combination for HCC. Moreover, no previous studies have reported the effect of NCTD on FGL1.

Current Landscape of Immune Checkpoint Inhibitor Therapy for Hepatocellular Carcinoma

The liver maintains a balance between immune tolerance and activation in its role as a filtration system. Chronic inflammation disrupts this immune microenvironment, thereby allowing for the rise and progression of cancer. Hepatocellular carcinoma (HCC) is a liver tumor generally diagnosed in the setting of chronic liver disease. When diagnosed early, the primary treatment is surgical resection, liver transplantation, or liver directed therapies. Unfortunately, patients with HCC often present at an advanced stage or with poor liver function, thereby limiting options. To further complicate matters, most systemic therapies are relatively limited and ineffective among patients with advanced disease. Recently, the IMbrave150 trial demonstrated that the combination of atezolizumab and bevacizumab was associated with better survival compared to sorafenib among patients with advanced HCC. As such, atezolizumab and bevacizumab is now recommended first-line therapy for these patients. Tumor cells work to create an immunotolerant environment by preventing the activation of stimulatory immunoreceptors and upregulating expression of proteins that bind inhibitory immunoreceptors. ICIs work to block these interactions and bolster the anti-tumor function of the immune system. We herein provide an overview of the use of ICIs in the treatment of HCC.

Recent advances of three-dimensional bioprinting technology in hepato-pancreato-biliary cancer models

Hepato-pancreato-biliary (HPB) cancer is a serious category of cancer including tumors originating in the liver, pancreas, gallbladder and biliary ducts. It is limited by two-dimensional (2D) cell culture models for studying its complicated tumor microenvironment including diverse contents and dynamic nature. Recently developed three-dimensional (3D) bioprinting is a state-of-the-art technology for fabrication of biological constructs through layer-by-layer deposition of bioinks in a spatially defined manner, which is computer-aided and designed to generate viable 3D constructs. 3D bioprinting has the potential to more closely recapitulate the tumor microenvironment, dynamic and complex cell-cell and cell-matrix interactions compared to the current methods, which benefits from its precise definition of positioning of various cell types and perfusing network in a high-throughput manner. In this review, we introduce and compare multiple types of 3D bioprinting methodologies for HPB cancer and other digestive tumors. We discuss the progress and application of 3D bioprinting in HPB and gastrointestinal cancers, focusing on tumor model manufacturing. We also highlight the current challenges regarding clinical translation of 3D bioprinting and bioinks in the field of digestive tumor research. Finally, we suggest valuable perspectives for this advanced technology, including combination of 3D bioprinting with microfluidics and application of 3D bioprinting in the field of tumor immunology.

Advances in Targeted Immunotherapy for Hepatobiliary Cancers

Cancer of the hepatobiliary system can be divided into primary liver cancer and biliary tract cancer (BTC), which includes hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA), and gallbladder cancer (GBC). These aggressive cancers often present at an advanced stage or among patients with poorly preserved liver function. The primary treatment for HCC and BTC when diagnosed early is surgical resection, but given the high rate of recurrence and often advanced stage at diagnosis, many patients will require systemic therapy. Unfortunately, even with systemic therapy, long-term survival is poor. The immune system plays an important role in preventing cancer progression. The unique immune environment of the liver and subsequent alterations to the immune microenvironment by tumor cells to create a favorable microenvironment plays a key role in the progression of HCC and BTC. Due to the paucity of effective systemic therapies and distinctive immune environment of the liver, research and clinical trials are investigating the use of immunotherapy in HCC and BTC. This review will focus on current immunotherapies and emerging data for the treatment of HCC and BTC.

Highlighting novel targets in immunotherapy for liver cancer

INTRODUCTION

Alterations to the hepatic immune microenvironment can play a key role in the development and progression of cancer. This is especially true in the liver due to its evolutionarily conserved immunotolerant state. The presence of chronic inflammation can facilitate the development and progression of hepatocellular carcinoma (HCC) by disrupting the hepatic immune microenvironment. Recently, the addition of the immunotherapy atezolizumab (PD-L1 inhibitor) with bevacizumab (VEGF inhibitor) became the recommended first-line systemic treatment for advanced HCC.

AREAS COVERED

Given recent updates to the guidelines and emerging data on immunotherapy, we herein provide an overview of currently available and novel immunotherapy approaches for the treatment of HCC, including immune checkpoint inhibitors, adoptive cell therapy, and vaccine development. This review performed an extensive literature search to investigate benchwork, clinical research, and clinical trials that evaluate current immunotherapy and establish new targets. Literature was focused on the most up-to-date research and included ongoing clinical trials to better evaluate the obstacles and future direction of the field.

EXPERT OPINION

Given the heterogeneity of HCC tumors, improvement in outcomes will likely come from targeting multiple immune mechanisms. Continued research and clinical trials of combination immunotherapies are necessary to move the field forward.

Primary Resistance to Immunotherapy-Based Regimens in First Line Hepatocellular Carcinoma: Perspectives on Jumping the Hurdle

Simple Summary

Immune checkpoint inhibitors (ICIs) had been explored extensively in patients affected by unresectable hepatocellular carcinoma. These agents were expected to be the keystones of the disease’s first-line treatment because they were theoretically able to revert the immune suppressive tumor microenvironment of the cancerous liver, and because of their manageable safety profile. However, when used as monotherapies, they showed important activity and efficacy limitations. In this mini-review, we summarize the characteristics of the different ICIs-based regimens which constitute the present gold standard of first-line treatment, then, moving from their shortcomings, we discuss the rationale supporting the strategies currently under investigation: systemic triplets and new paradigms of immune-therapeutic agents such as CAR-T and vaccines.

Abstract

Immune checkpoint inhibitors (ICIs) are a key component of different stages of hepatocellular carcinoma (HCC) treatment, particularly in the first line of treatment. A lesson on the primary resistance which hampers their efficacy and activity was learned from the failure of the trials which tested them as first-line mono-therapies. Despite the combination of anti-PD(L)1 agents with anti-VEGF, anti CTLA4, or TKIs demonstrating relevant improvements in efficacy, the “doublets strategy” still shows room for improvement, due to a limited overall survival benefit and a high rate of progressive disease as best response. In this review, we discuss the results from the currently tested doublet strategies (i.e., atezolizumab+bevacizumab, durvalumab+tremelimumab with a mention to the newly presented ICIs/TKIs combinations), which highlight the need for therapeutic improvement. Furthermore, we examine the rationale and provide an overview of the ongoing trials testing the treatment intensification strategy with triplet drugs: anti-PD1+anti-CTLA4+anti-VEGF/TKIs and anti-PD1+anti-VEGF+alternative immunity targets. Lastly, we report on the alternative strategy to integrate ICIs into the new paradigm of immune therapeutics constituted by CAR-T and anti-cancer vaccines. This review provides up-to-date knowledge of ongoing clinical trials of the aforementioned strategies and critical insight into their mechanistic premises.

tRNA‑derived fragment tRF‑Glu49 inhibits cell proliferation, migration and invasion in cervical cancer by targeting FGL1

A transfer RNA (tRNA)-derived fragment (tRF) was found to be a new possible biological marker and target in carcinoma therapy. However, the effect exerted by tRFs on cervical carcinoma remains unclear. In the present study, the potential tumor suppressor gene tRF-Glu49 was identified in cervical carcinoma through tRF and tiRNA microarray investigation. A reverse transcription-quantitative PCR assay then demonstrated that tRF-Glu49 was downregulated in the cervical carcinoma tissue. Further clinicopathological analysis proved that tRF-Glu49 was associated with less aggressive clinical features and improved prognosis. Cell Counting Kit-8 tests, Transwell and Matrigel tests, and xCELLigence system tests revealed that tRF-Glu49 inhibited cervical cell proliferation, migration and invasion processes. Mechanistic investigation revealed that tRF-Glu49 directly regulated the oncogene, fibrinogen-like protein-1 (FGL1). In general, according to the result achieved in the present study, tRF-Glu49 can modulate cervical cell proliferation, migration, and invasion processes through the target process for FGL1, and tRF-Glu49 is likely to be a possible prognostic biological marker in patients with cervical carcinoma.

Research on the Construction of Bispecific-Targeted Sustained-Release Drug-Delivery Microspheres and Their Function in Treatment of Hepatocellular Carcinoma

Lenvatinib (LEN) is approved as one of the commonly used drugs in the treatment of hepatocellular carcinoma (HCC). It is recognized to be a novel therapeutic choice for the direct and targeted delivery of effective drugs to HCC tumor sites. The key to the proposed method lies in the requirement for efficient targeted drug delivery carriers with targeting performance to deliver effective drugs directly and safely to tumor lesions. Methods: Here, magnetic liposomes (MLs) were modified by phosphatidylinositol proteoglycan 3 (GPC3) and epithelial cell adhesion molecules (EpCAMs). Subsequently, bispecific-targeted sustained-release drug-loaded microspheres containing LEN (GPC3/EpCAM-LEN-MLs) were constructed. In addition, both cytotoxicity and magnetic resonance imaging (MRI) analyses were performed to establish a mouse model and further perform corresponding performance assessments. Results: The corresponding results showed that GPC3/EpCAM-LEN-MLs were spherical-shaped and evenly dispersed. The encapsulation and drug-loading efficiencies were 91.08% ± 1.83% and 8.22% ± 1.24%, respectively. Meanwhile, GPC3/EpCAM-LEN-MLs showed a high inhibition rate on the proliferation of HCC cells and significantly increased their apoptosis. Furthermore, MRI revealed that the system possessed the function of tracking and localizing tumor cells, and animal experiments verified that it could exert the function of disease diagnosis. Conclusions: Our experiments successfully constructed a safe and efficient bispecific-targeted sustained-release drug delivery system for HCC tumor cells. It provides a useful diagnostic and therapeutic scheme for the clinical diagnosis and targeted therapy of HCC. Moreover, it can be used as a potential tumor-specific MRI contrast agent for the localization and diagnosis of malignant tumors.

Exosomes derived from fibrinogen-like protein 1-overexpressing bone marrow-derived mesenchymal stem cells ameliorates rheumatoid arthritis

Rheumatoid arthritis (RA) is a most common chronic joint disease belonging to inflammatory autoimmune disease. The aim of this study was to determine the role and mechanism of bone marrow mesenchymal stem cells (BMSCs)-derived exosomes and fibrinogen-like protein 1 (FGL1) overexpression exosomes shuttled by BMSCs (FGL1-Exos) on RA. All of the exosomes were visualized by transmission electron microscope (TEM) and the characteristic proteins were detected by western blot. To investigate the therapeutic effect of FGL1-Exos, RA-FLSs were activated by TNF-α and RA rat model was established by collagen incomplete Freund's adjuvant. Cell viability, apoptosis, inflammation factors, and protein levels were detected by CCK-8, flow cytometry, enzyme-linked immunosorbent assay and western blot, respectively. Hematoxylin and eosin and safranin O staining were used to detect the histopathology changes. Cell apoptosis and FGL1 expression in knee joint were detected by immunofluorescence. The results showed that FGL1-Exos could inhibit the cell viability meanwhile increase the cell apoptosis in RA-FLSs. Meanwhile, FGL1-Exos could effectively suppress the inflammation score, joint destruction, and inflammatory response in RA rat model. FGL1-Exos directly inhibited cell apoptosis of RA-FLSs and RA rat model by suppressing the inflammatory cytokines, specific rheumatoid markers, immunological markers meanwhile meditating the NF-κB pathway. Our results indicate that FGL1 was a therapeutic potential target in RA therapy.