A bispecific antibody targeting GPC3 and CD47 induced enhanced antitumor efficacy against dual antigen-expressing HCC

Deciphering the role of CD47 in cancer immunotherapy

BACKGROUND

Immunotherapy has emerged as a novel strategy for cancer treatment following surgery, radiotherapy, and chemotherapy. Immune checkpoint blockade and Chimeric antigen receptor (CAR)-T cell therapies have been successful in clinical trials. Cancer cells evade immune surveillance by hijacking inhibitory pathways via overexpression of checkpoint genes. The Cluster of Differentiation 47 (CD47) has emerged as a crucial checkpoint for cancer immunotherapy by working as a "don't eat me" signal and suppressing innate immune signaling. Furthermore, CD47 is highly expressed in many cancer types to protect cancer cells from phagocytosis via binding to SIRPα on phagocytes. Targeting CD47 by either interrupting the CD47-SIRPα axis or combing with other therapies has been demonstrated as an encouraging therapeutic strategy in cancer immunotherapy. Antibodies and small molecules that target CD47 have been explored in pre- and clinical trials. However, formidable challenges such as the anemia and palate aggregation cannot be avoided because of the wide presentation of CD47 on erythrocytes.

AIM OF VIEW

This review summarizes the current knowledge on the regulation and function of CD47, and provides a new perspective for immunotherapy targeting CD47. It also highlights the clinical progress of targeting CD47 and discusses challenges and potential strategies.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review provides a comprehensive understanding of targeting CD47 in cancer immunotherapy, it also augments the concept of combination immunotherapy strategies by employing both innate and adaptive immune responses.

GPC3-targeted CAR-M cells exhibit potent antitumor activity against hepatocellular carcinoma

Chimeric antigen receptor (CAR)-modified macrophages are a promising treatment for solid tumor. So far the potential effects of CAR-M cell therapy have rarely been investigated in hepatocellular carcinoma (HCC). Glypican-3 (GPC3) is a biomarker for a variety of malignancies, including liver cancer, which is not expressed in most adult tissues. Thus, it is an ideal target for the treatment of HCC. In this study, we engineered mouse macrophage cells with CAR targeting GPC3 and explored its therapeutic potential in HCC. First, we generated a chimeric adenoviral vector (Ad5f35) delivering an anti-GPC3 CAR, Ad5f35-anti-GPC3-CAR, which using the CAR construct containing the scFv targeting GPC3 and CD3ζ intracellular domain. Phagocytosis and killing effect indicated that macrophages transduced with Ad5f35-anti-GPC3-CAR (GPC3 CAR-Ms) exhibited antigen-specific phagocytosis and tumor cell clearance in vitro, and GPC3 CAR-Ms showed significant tumor-killing effects and promoted expression of pro-inflammatory (M1) cytokines and chemokines. In 3D NACs-origami spheroid model of HCC, CAR-Ms were further demonstrated to have a significant tumor killing effect. Together, our study provides a new strategy for the treatment of HCC through CAR-M cells targeting GPC3, which provides a basis for the research and treatment of hepatocellular carcinoma.

The role of tumor-associated macrophages in hepatocellular carcinoma-from bench to bedside: A review

Hepatocellular carcinoma is one of the most common cancers worldwide. Despite progress in treatment, recurrence after radical treatment is common, and the prognosis remains poor for patients with advanced disease. Therefore, there is a need to identify prognostic and predictive factors for the response to therapy or more intensive surveillance or treatment. Because the tumor microenvironment plays a crucial role in the development of cancer and metastasis, it is a crucial need to understand processes that are involved in carcinogenesis. Within the microenvironment, several immune cells with different roles are present. One of the most important of these is tumor-associated macrophages. These cells may exert either antitumor or protumor roles. Several studies have suggested that tumor-associated macrophages can be used as prognostic markers. Furthermore, they may be involved in resistance to immunotherapy or systemic treatment. As they play an important role in cancer development, tumor-associated macrophages are also a good target for therapy. In this review, we briefly summarize recent progress on knowledge regarding the basic molecular characteristics, impact on prognosis and potential clinical implications of tumor-associated macrophages in hepatocellular carcinoma.

Multifunctional Bispecific Nanovesicles Targeting SLAMF7 Trigger Potent Antitumor Immunity

The effectiveness of immune checkpoint inhibitor (ICI) therapy is hindered by the ineffective infiltration and functioning of cytotoxic T cells and the immunosuppressive tumor microenvironment (TME). Signaling lymphocytic activation molecule family member 7 (SLAMF7) is a pivotal co-stimulatory receptor thought to simultaneously trigger NK-cell, T-cell, and macrophage antitumor cytotoxicity. However, the potential of this collaborative immune stimulation in antitumor immunity for solid tumors is underexplored due to the exclusive expression of SLAMF7 by hematopoietic cells. Here, we report the development and characterization of multifunctional bispecific nanovesicles (NVs) targeting SLAMF7 and glypican-3-a hepatocellular carcinoma (HCC)-specific tumor antigen. We found that by effectively "decorating" the surfaces of solid tumors with SLAMF7, these NVs directly induced potent and specific antitumor immunity and remodeled the immunosuppressive TME, sensitizing the tumors to programmed cell death protein 1 (PD1) blockade. Our findings highlight the potential of SLAMF7-targeted multifunctional bispecific NVs as an anticancer strategy with implications for designing next-generation targeted cancer therapies.

Macrophages as Targets in Hepatocellular Carcinoma Therapy

Hepatocellular carcinoma (HCC) is a malignant tumor with a complex and diverse immunosuppressive microenvironment. Tumor-associated macrophages (TAM) are an essential component of the tumor immune microenvironment. TAMs typically exist in two primary states: anti-tumor M1 macrophages and protumor M2 macrophages. Remarkably, TAMs possess high plasticity, enabling them to switch between different subtypes or alter their biological functions in response to the tumor microenvironment. Based on research into the biological role of TAMs in the occurrence and development of malignant tumors, including HCC, TAMs are emerging as promising targets for novel tumor treatment strategies. In this review, we provide a detailed introduction to the origin and subtypes of TAMs, elucidate their interactions with other cells in the complex tumor microenvironment of HCC, and describe the biological roles, characteristics, and mechanisms of TAMs in the progression of HCC. Furthermore, we furnish an overview of the latest therapeutic strategies targeting TAMs.

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.

Insights in Molecular Therapies for Hepatocellular Carcinoma

We conducted a comprehensive review of the current literature of published data and clinical trials (MEDLINE), as well as published congress contributions and active recruiting clinical trials on targeted therapies in hepatocellular carcinoma. Combinations of different agents and medical therapy along with radiological interventions were analyzed for the setting of advanced HCC. Those settings were also analyzed in combination with adjuvant situations after resection or radiological treatments. We summarized the current knowledge for each therapeutic setting and combination that currently is or has been under clinical evaluation. We further discuss the results in the background of current treatment guidelines. In addition, we review the pathophysiological mechanisms and pathways for each of these investigated targets and drugs to further elucidate the molecular background and underlying mechanisms of action. Established and recommended targeted treatment options that already exist for patients are considered for systemic treatment: atezolizumab/bevacizumab, durvalumab/tremelimumab, sorafenib, lenvatinib, cabozantinib, regorafenib, and ramucirumab. Combination treatment for systemic treatment and local ablative treatment or transarterial chemoembolization and adjuvant and neoadjuvant treatment strategies are under clinical investigation.

Role of immunotherapies and stem cell therapy in the management of liver cancer: A comprehensive review

Liver cancer (LC) is the sixth most common disease and the third most common cause of cancer-related mortality. The WHO predicts that more than 1 million deaths will occur from LC by 2030. Hepatocellular carcinoma (HCC) is a common form of primary LC. Today, the management of LC involves multiple disciplines, and multimodal therapy is typically selected on an individual basis, considering the intricate interactions between the patient's overall health, the stage of the tumor, and the degree of underlying liver disease. Currently, the treatment of cancers, including LC, has undergone a paradigm shift in the last ten years because of immuno-oncology. To treat HCC, immune therapy approaches have been developed to enhance or cause the body's natural immune response to specifically target tumor cells. In this context, immune checkpoint pathway inhibitors, engineered cytokines, adoptive cell therapy, immune cells modified with chimeric antigen receptors, and therapeutic cancer vaccines have advanced to clinical trials and offered new hope to cancer patients. The outcomes of these treatments are encouraging. Additionally, treatment using stem cells is a new approach for restoring deteriorated tissues because of their strong differentiation potential and capacity to release cytokines that encourage cell division and the formation of blood vessels. Although there is no proof that stem cell therapy works for many types of cancer, preclinical research on stem cells has shown promise in treating HCC. This review provides a recent update regarding the impact of immunotherapy and stem cells in HCC and promising outcomes.

Nanosystem Delivers Senescence Activators and Immunomodulators to Combat Liver Cancer

CD47 blockade has emerged as a promising immunotherapy against liver cancer. However, the optimization of its antitumor effectiveness using efficient drug delivery systems or combinations of therapeutic agents remains largely incomplete. Here, patients with liver cancer co-expressing CD47 and CDC7 (cell division cycle 7, a negative senescence-related gene) are found to have the worst prognosis. Moreover, CD47 is highly expressed, and senescence is inhibited after the development of chemoresistance, suggesting that combination therapy targeting CD47 and CDC7 to inhibit CD47 and induce senescence may be a promising strategy for liver cancer. The efficacy of intravenously administered CDC7 and CD47 inhibitors is limited by low uptake and short circulation times. Here, inhibitors are coloaded into a dual-targeted nanosystem. The sequential release of the inhibitors from the nanosystem under acidic conditions first induces cellular senescence and then promotes immune responses. In an in situ liver cancer mouse model and a chemotherapy-resistant mouse model, the nanosystem effectively inhibited tumor growth by 90.33% and 85.15%, respectively. Overall, the nanosystem in this work achieved the sequential release of CDC7 and CD47 inhibitors in situ to trigger senescence and induce immunotherapy, effectively combating liver cancer and overcoming chemoresistance.

Immunosuppressive tumor microenvironment and immunotherapy of hepatocellular carcinoma: current status and prospectives

Hepatocellular carcinoma (HCC) is a major health concern worldwide, with limited therapeutic options and poor prognosis. In recent years, immunotherapies such as immune checkpoint inhibitors (ICIs) have made great progress in the systemic treatment of HCC. The combination treatments based on ICIs have been the major trend in this area. Recently, dual immune checkpoint blockade with durvalumab plus tremelimumab has also emerged as an effective treatment for advanced HCC. However, the majority of HCC patients obtain limited benefits. Understanding the immunological rationale and exploring novel ways to improve the efficacy of immunotherapy has drawn much attention. In this review, we summarize the latest progress in this area, the ongoing clinical trials of immune-based combination therapies, as well as novel immunotherapy strategies such as chimeric antigen receptor T cells, personalized neoantigen vaccines, oncolytic viruses, and bispecific antibodies.

Targeting CEACAM5-positive solid tumors using NILK-2401, a novel CEACAM5xCD47 κλ bispecific antibody

Background

Blocking the CD47 "don't eat me"-signal on tumor cells with monoclonal antibodies or fusion proteins has shown limited clinical activity in hematologic malignancies and solid tumors thus far. Main side effects are associated with non-tumor targeted binding to CD47 particularly on blood cells.

Methods

We present here the generation and preclinical development of NILK-2401, a CEACAM5×CD47 bispecific antibody (BsAb) composed of a common heavy chain and two different light chains, one kappa and one lambda, determining specificity (so-called κλ body format).

Results

NILK-2401 is a fully human BsAb binding the CEACAM5 N-terminal domain on tumor cells by its lambda light chain arm with an affinity of ≈4 nM and CD47 with its kappa chain arm with an intendedly low affinity of ≈500 nM to enabling tumor-specific blockade of the CD47-SIRPα interaction. For increased activity, NILK-2401 features a functional IgG1 Fc-part. NILK-2401 eliminates CEACAM5-positive tumor cell lines (3/3 colorectal, 2/2 gastric, 2/2 lung) with EC50 for antibody-dependent cellular phagocytosis and antibody-dependent cellular cytotoxicity ranging from 0.38 to 25.84 nM and 0.04 to 0.25 nM, respectively. NILK-2401 binds neither CD47-positive/CEACAM5-negative cell lines nor primary epithelial cells. No erythrophagocytosis or platelet activation is observed. Quantification of the pre-existing NILK-2401-reactive T-cell repertoire in the blood of 14 healthy donors with diverse HLA molecules shows a low immunogenic potential. In vivo, NILK-2401 significantly delayed tumor growth in a NOD-SCID colon cancer model and a syngeneic mouse model using human CD47/human SIRPα transgenic mice and prolonged survival. In cynomolgus monkeys, single doses of 0.5 and 20 mg/kg were well tolerated; PK linked to anti-CD47 and Fc-binding seemed to be more than dose-proportional for Cmax and AUC0-inf. Data were validated in human FcRn TG32 mice. Combination of a CEACAM5-targeting T-cell engager (NILK-2301) with NILK-2401 can either boost NILK-2301 activity (Emax) up to 2.5-fold or allows reaching equal NILK-2301 activity at >600-fold (LS174T) to >3,000-fold (MKN-45) lower doses.

Conclusion

NILK-2401 combines promising preclinical activity with limited potential side effects due to the tumor-targeted blockade of CD47 and low immunogenicity and is planned to enter clinical testing.

Delivery of CD47-SIRPα checkpoint blocker by BCMA-directed UCAR-T cells enhances antitumor efficacy in multiple myeloma

In the treatment of relapsed or refractory multiple myeloma patients, BCMA-directed autologous CAR-T cells have showed excellent anti-tumor activity. However, their widespread application is limited due to the arguably cost and time-consuming. Multiple myeloma cells highly expressed CD47 molecule and interact with the SIRPα ligand on the surface of macrophages, in which evade the clearance of macrophages through the activation of "don't eat me" signal. In this study, a BCMA-directed universal CAR-T cells, BC404-UCART, secreting a CD47-SIRPα blocker was developed using CRISPR/Cas9 gene-editing system. BC404-UCART cells significantly inhibited tumor growth and prolonged the survival of mice in the xenograft model. The anti-tumor activity of BC404-UCART cells was achieved via two mechanisms, on the one hand, the UCAR-T cells directly killed tumor cells, on the other hand, the BC404-UCART cells enhanced the phagocytosis of macrophages by secreting anti-CD47 nanobody hu404-hfc fusion that blocked the "don't eat me" signal between macrophages and tumor cells, which provides a potential strategy for the development of novel "off-the-shelf" cellular immunotherapies for the treatment of multiple myeloma.

From clinical management to personalized medicine: novel therapeutic approaches for ovarian clear cell cancer

Ovarian clear-cell cancer is a rare subtype of epithelial ovarian cancer with unique clinical and biological features. Despite optimal cytoreductive surgery and platinum-based chemotherapy being the standard of care, most patients experience drug resistance and a poor prognosis. Therefore, novel therapeutic approaches have been developed, including immune checkpoint blockade, angiogenesis-targeted therapy, ARID1A synthetic lethal interactions, targeting hepatocyte nuclear factor 1β, and ferroptosis. Refining predictive biomarkers can lead to more personalized medicine, identifying patients who would benefit from chemotherapy, targeted therapy, or immunotherapy. Collaboration between academic research groups is crucial for developing prognostic outcomes and conducting clinical trials to advance treatment for ovarian clear-cell cancer. Immediate progress is essential, and research efforts should prioritize the development of more effective therapeutic strategies to benefit all patients.

The role and mechanism of HIF-1α-mediated glypican-3 secretion in hypoxia-induced tumor progression in hepatocellular carcinoma

OBJECTIVE

To explore the expression and secretion mechanism of glypican-3 (GPC3) in hepatocellular carcinoma (HCC) cells under hypoxic conditions, and its role in tumor progression.

METHODS

Huh7 cells with and without the knockdown of hypoxia-inducible factor 1-alpha (HIF-1α) were cultured under 1% O2 for varying durations to induce hypoxia. The expression levels of GPC3, HSP70, CD63, STX11 and SYT7 in the cytoplasm and exosomes of Huh7 cells were evaluated by western blotting and immunofluorescence. GPC3 protein expression was further measured in cells treated with GW4869 under hypoxic conditions. Huh7 cells and human umbilical vein endothelial cells (HUVECs) were cultured with the exosomes extracted from the control and GPC3-knockdown cells, the cell proliferation, migration, epithelial-mesenchymal transition (EMT), invasion, and in vitro angiogenesis were analyzed. Tumor xenografts were established to assess the role of GPC3-deficient exosomes in tumor growth.

RESULTS

Hypoxic culture conditions downregulated GPC3, STX11 and SYT7 protein levels in the Huh7 cells and upregulated GPC3 mRNA, and also increased GPC3 protein expression in the exosomes. HIF-1α knockdown, as well as treatment with GW4869, upregulated GPC3 protein in the Huh7 cells grown under 1% O2, but downregulated exosomal GPC3. Furthermore, exosomes derived from the GPC3-knockdown cells inhibited the proliferation and migration of Huh7 cells, decreased the expression of N-cadherin, vimentin, β-catenin, c-Myc and cyclin D1, and increased that of E-cadherin. Likewise, the GPC3-deficient exosomes also suppressed the invasion and tube formation ability of the HUVECs compared to that of control cells. Consistent with the in vitro results, the GPC3-deficient exosomes also repressed tumor growth in vivo.

CONCLUSION

Hypoxia promoted secretion of exosomal GPC3 through the activation of HIF-1α. GPC3-deficient exosomes inhibited the proliferation, migration and EMT of HCC cells via the Wnt/β-catenin signaling pathway, and suppressed the angiogenic potential of HUVECs. This provided a novel understanding of the role of exosomal GPC3 in HCC progression.

Tumor Microenvironment Composition and Related Therapy in Hepatocellular Carcinoma

Globally, primary liver cancer is the third leading cause of cancer death, and hepatocellular carcinoma (HCC) accounts for 75%-95%. The tumor microenvironment (TME), composed of the extracellular matrix, helper cells, immune cells, cytokines, chemokines, and growth factors, promotes the immune escape, invasion, and metastasis of HCC. Tumor metastasis and postoperative recurrence are the main threats to the long-term prognosis of HCC. TME-related therapies are increasingly recognized as effective treatments. Molecular-targeted therapy, immunotherapy, and their combined therapy are the main approaches. Immunotherapy, represented by immune checkpoint inhibitors (ICIs), and targeted therapy, highlighted by tyrosine kinase inhibitors (TKIs), have greatly improved the prognosis of HCC. This review focuses on the TME compositions and emerging therapeutic approaches to TME in HCC.

Opportunities and challenges of CD47-targeted therapy in cancer immunotherapy

Cancer immunotherapy has emerged as a promising strategy for the treatment of cancer, with the tumor microenvironment (TME) playing a pivotal role in modulating the immune response. CD47, a cell surface protein, has been identified as a crucial regulator of the TME and a potential therapeutic target for cancer therapy. However, the precise functions and implications of CD47 in the TME during immunotherapy for cancer patients remain incompletely understood. This comprehensive review aims to provide an overview of CD47's multifaced role in TME regulation and immune evasion, elucidating its impact on various types of immunotherapy outcomes, including checkpoint inhibitors and CAR T-cell therapy. Notably, CD47-targeted therapies offer a promising avenue for improving cancer treatment outcomes, especially when combined with other immunotherapeutic approaches. The review also discusses current and potential CD47-targeted therapies being explored for cancer treatment and delves into the associated challenges and opportunities inherent in targeting CD47. Despite the demonstrated effectiveness of CD47-targeted therapies, there are potential problems, including unintended effects on healthy cells, hematological toxicities, and the development if resistance. Consequently, further research efforts are warranted to fully understand the underlying mechanisms of resistance and to optimize CD47-targeted therapies through innovative combination approaches, ultimately improving cancer treatment outcomes. Overall, this comprehensive review highlights the significance of CD47 as a promising target for cancer immunotherapy and provides valuable insight into the challenges and opportunities in developing effective CD47-targeted therapies for cancer treatment.

Multiparametric MRI combined with clinical factors to predict glypican-3 expression of hepatocellular carcinoma

Objectives

The present study aims at establishing a noninvasive and reliable model for the preoperative prediction of glypican 3 (GPC3)-positive hepatocellular carcinoma (HCC) based on multiparametric magnetic resonance imaging (MRI) and clinical indicators.

Methods

As a retrospective study, the subjects included 158 patients from two institutions with surgically-confirmed single HCC who underwent preoperative MRI between 2020 and 2022. The patients, 102 from institution I and 56 from institution II, were assigned to the training and the validation sets, respectively. The association of the clinic-radiological variables with the GPC3 expression was investigated through performing univariable and multivariable logistic regression (LR) analyses. The synthetic minority over-sampling technique (SMOTE) was used to balance the minority group (GPC3-negative HCCs) in the training set, and diagnostic performance was assessed by the area under the curve (AUC) and accuracy. Next, a prediction nomogram was developed and validated for patients with GPC3-positive HCC. The performance of the nomogram was evaluated through examining its calibration and clinical utility.

Results

Based on the results obtained from multivariable analyses, alpha-fetoprotein levels > 20 ng/mL, 75th percentile ADC value < 1.48 ×103 mm2/s and R2* value ≥ 38.6 sec-1 were found to be the significant independent predictors of GPC3-positive HCC. The SMOTE-LR model based on three features achieved the best predictive performance in the training (AUC, 0.909; accuracy, 83.7%) and validation sets (AUC, 0.829; accuracy, 82.1%) with a good calibration performance and clinical usefulness.

Conclusions

The nomogram combining multiparametric MRI and clinical indicators is found to have satisfactory predictive efficacy for preoperative prediction of GPC3-positive HCC. Accordingly, the proposed method can promote individualized risk stratification and further treatment decisions of HCC patients.

A novel bispecific antibody as an immunotherapeutic agent in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) remains one of the most common and highly fatal malignancies in humans worldwide with increasing prevalence and limited therapeutic options. For many decades, many researchers have attempted to find effective curative methods for HCC and great strides have been made. GPC3 is overexpressed in HCC, but not in normal liver, making it a rational immunotherapeutic target for HCC. GC33, a humanized mAb directed against GPC3, is a safe and well-tolerated therapy choice for patients with HCC, which tested in a phase I trial in advanced HCC patients. Phase II trials of GC33 to evaluate its efficacy and safety in advanced or metastatic HCC, showed no significant differences in overall survival and progression-free survival compared with the placebo. Retrospective analysis indicates that high drug exposure and high CD16 expression may contribute to the clinical efficacy of GC33. Chugai Pharmaceutical has restarted its Phase I trial of GC33, continuing to explore its clinical value targeting GPC3 in solid tumors. To enhance the antitumor potency of GC33, we designed a GPC3/CD16A bispecific antibody (QDEB). In this study, we obtained QDEB at high purity and assessed its effectiveness in the therapy of HCC compared with GC33. In vitro cytotoxicity assays and in vivo experiments demonstrated that QDEB could enhance anti-tumor efficacy compared with GC33. CD16A activation and increased cytokines release were associated with higher anti-tumor activity. In conclusion, this bispecific antibody may possibly help develop new therapeutic strategies for HCC and develop new treatment options in the future.

Unleashing the efficacy of immune checkpoint inhibitors for advanced hepatocellular carcinoma: factors, strategies, and ongoing trials

Hepatocellular carcinoma (HCC) is a prevalent primary liver cancer, representing approximately 85% of cases. The diagnosis is often made in the middle and late stages, necessitating systemic treatment as the primary therapeutic option. Despite sorafenib being the established standard of care for advanced HCC in the past decade, the efficacy of systemic therapy remains unsatisfactory, highlighting the need for novel treatment modalities. Recent breakthroughs in immunotherapy have shown promise in HCC treatment, particularly with immune checkpoint inhibitors (ICIs). However, the response rate to ICIs is currently limited to approximately 15%-20% of HCC patients. Recently, ICIs demonstrated greater efficacy in "hot" tumors, highlighting the urgency to devise more effective approaches to transform "cold" tumors into "hot" tumors, thereby enhancing the therapeutic potential of ICIs. This review presented an updated summary of the factors influencing the effectiveness of immunotherapy in HCC treatment, identified potential combination therapies that may improve patient response rates to ICIs, and offered an overview of ongoing clinical trials focusing on ICI-based combination therapy.

Delta-radiomics models based on multi-phase contrast-enhanced magnetic resonance imaging can preoperatively predict glypican-3-positive hepatocellular carcinoma

Objectives: The aim of this study is to investigate the value of multi-phase contrast-enhanced magnetic resonance imaging (CE-MRI) based on the delta radiomics model for identifying glypican-3 (GPC3)-positive hepatocellular carcinoma (HCC). Methods: One hundred and twenty-six patients with pathologically confirmed HCC (training cohort: n = 88 and validation cohort: n = 38) were retrospectively recruited. Basic information was obtained from medical records. Preoperative multi-phase CE-MRI images were reviewed, and the 3D volumes of interest (VOIs) of the whole tumor were delineated on non-contrast T1-weighted imaging (T1), arterial phase (AP), portal venous phase (PVP), delayed phase (DP), and hepatobiliary phase (HBP). One hundred and seven original radiomics features were extracted from each phase, and delta-radiomics features were calculated. After a two-step feature selection strategy, radiomics models were built using two classification algorithms. A nomogram was constructed by combining the best radiomics model and clinical risk factors. Results: Serum alpha-fetoprotein (AFP) (p = 0.013) was significantly related to GPC3-positive HCC. The optimal radiomics model is composed of eight delta-radiomics features with the AUC of 0.805 and 0.857 in the training and validation cohorts, respectively. The nomogram integrated the radiomics score, and AFP performed excellently (training cohort: AUC = 0.844 and validation cohort: AUC = 0.862). The calibration curve showed good agreement between the nomogram-predicted probabilities and GPC3 actual expression in both training and validation cohorts. Decision curve analysis further demonstrates the clinical practicality of the nomogram. Conclusion: Multi-phase CE-MRI based on the delta-radiomics model can non-invasively predict GPC3-positive HCC and can be a useful method for individualized diagnosis and treatment.

Dual mRNA co-delivery for in situ generation of phagocytosis-enhanced CAR macrophages augments hepatocellular carcinoma immunotherapy

Hepatocellular carcinoma (HCC) is a prevalent and lethal disease, and tumor regression rarely occurs in advanced HCC patients due to limited effective therapies. Given the enrichment of macrophages in HCC and their role in tumor immunity, transforming them into chimeric antigen receptor macrophages (CAR-Ms) is thought to increase HCC cell-directed phagocytosis and tumoricidal immunity. To test this hypothesis, mRNA encoding CAR is encapsulated in a lipid nanoparticle (LNP) that targets liver macrophages. Notably, the LNPs adsorb specific plasma proteins that enable them to target HCC-associated macrophages. Moreover, mRNA encoding Siglec-G lacking ITIMs (Siglec-GΔITIMs) is codelivered to liver macrophages by LNP to relieve CD24-mediated CAR-Ms immune suppression. Mice treated with LNPs generating CAR-Ms as well as CD24-Siglec-G blockade significantly elevate the phagocytic function of liver macrophages, reduce tumor burden and increase survival time in an HCC mouse model. Arguably, our work suggests an efficacious and flexible strategy for the treatment of HCC and warrants further rigorous evaluation in clinical trials.

High-affinity decoy protein, nFD164, with an inactive Fc region as a potential therapeutic drug targeting CD47

CD47, as an innate immune checkpoint molecule, is an important target of cancer immunotherapy. We previously reported that a high-affinity SIRPα variant FD164 fused with IgG1 subtype Fc showed a better antitumor effect than wild-type SIRPα in an immunodeficient tumor-bearing model. However, CD47 is widely expressed in blood cells, and the drugs targeting CD47 may cause potential hematological toxicity. Herein, we modified the FD164 molecule by Fc mutation (N²⁹⁷A) to inactivate the Fc-related effector function and named it nFD164. Moreover, we further studied the potential of nFD164 as a candidate drug targeting CD47, including the stability, in vitro activity, antitumor activity of single or combined drugs in vivo, and hematological toxicity in humanized CD47/SIRPα transgenic mouse model. The results show that nFD164 maintains strong binding activity to CD47 on tumor cells, but has weak binding activity with red blood cells or white blood cells, and nFD164 has good drug stability under accelerated conditions (high temperature, bright light and freeze-thaw cycles). More importantly, in the immunodeficient or humanized CD47/SIRPα transgenic mice bearing tumor model, the combination of nFD164 and anti-CD20 antibody or anti-mPD-1 antibody had a synergistic antitumor effect. Especially in transgenic mouse models, nFD164 combined with anti-mPD-1 significantly enhanced tumor suppressive activity compared with anti-mPD-1 (P < 0.01) or nFD164 (P < 0.01) as a single drug and had fewer hematology-related side effects than FD164 or Hu5F9-G4. When these factors are taken together, nFD164 is a promising high-affinity CD47-targeting drug candidate with better stability, potential antitumor activity, and improved safety profile.

Oncofetal protein glypican-3 is a biomarker and critical regulator of function for neuroendocrine cells in prostate cancer

Neuroendocrine (NE) cells comprise ~1% of epithelial cells in benign prostate and prostatic adenocarcinoma (PCa). However, they become enriched in hormonally treated and castration-resistant PCa (CRPC). In addition, close to 20% of hormonally treated tumors recur as small cell NE carcinoma (SCNC), composed entirely of NE cells, which may be the result of clonal expansion or lineage plasticity. Since NE cells do not express androgen receptors (ARs), they are resistant to hormonal therapy and contribute to therapy failure. Here, we describe the identification of glypican-3 (GPC3) as an oncofetal cell surface protein specific to NE cells in prostate cancer. Functional studies revealed that GPC3 is critical to the viability of NE tumor cells and tumors displaying NE differentiation and that it regulates calcium homeostasis and signaling. Since our results demonstrate that GPC3 is specifically expressed by NE cells, patients with confirmed SCNC may qualify for GPC3-targeted therapy which has been developed in the context of liver cancer and displays minimal toxicity due to its tumor-specific expression. © 2023 The Pathological Society of Great Britain and Ireland.

An electrochemical immunosensor for the detection of Glypican-3 based on enzymatic ferrocene-tyramine deposition reaction

An ultrasensitive electrochemical immunosensor based on signal amplification of the deposition of the electroactive ferrocene-tyramine (Fc-Tyr) molecule, catalyzed by horseradish peroxidase (HRP), was constructed for the detection of the liver cancer marker Glypican-3 (GPC3). Functional electroactive molecule Fc-Tyr is reported to exhibit both the enzymatic cascade catalytic activity of tyramine signal amplification (TSA) and the excellent redox properties of ferrocene. In terms of design, the low matrix effects inherent in using the magnetic bead platforms, a quasi-homogeneous system, allowed capturing the target protein GPC3 without sample pretreatment, and loading HRP to trigger the TSA, which induced a large amount of Fc-Tyr deposited on the electrode surface layer by layer as a signal probe for the detection of GPC3. The concept of Fc-Tyr as an electroactive label was validated, GPC3 biosensor exhibited high selectivity and sensitivity to GPC3 in the range of 0.1 ng mL^-1-1 μg mL^-1. Finally, the sensor was used simultaneously with ELISA to assess GPC3 levels in the serum of clinical liver cancer patients, and the results showed consistency, with a recovery of 98.33-105.35% and a relative standard deviation (RSD) of 4.38-8.18%, providing a theoretical basis for achieving portable, rapid and point of care testing (POCT) of tumor markers.

Bispecific GPC3/PD‑1 CAR‑T cells for the treatment of HCC

Constantly stimulated by the tumor microenvironment (TME), programmed death 1 (PD‑1) is elevated, and it interacts with PD ligand 1 (PD‑L1), rendering chimeric antigen receptor (CAR)‑T cells dysfunctional. Hence, CAR‑T cells immune to PD‑1‑induced immunosuppression were constructed to improve the function of CAR‑T cells in hepatocellular carcinoma (HCC). Double‑target CAR‑T cells, targeting glypican‑3 (GPC3) [a tumour-associated antigen (TAA)] and hindering PD‑1‑PD‑L1 binding, were established. The expression of GPC3, PD‑L1, and inhibitory receptors was measured using flow cytometry. The cytotoxicity, cytokine release, and differentiation level of CAR‑T cells were determined using lactate dehydrogenase release assay, enzyme‑linked immunosorbent assay, and flow cytometry, respectively. HCC cells were targeted and eliminated by double‑target CAR‑T cells. These double‑target CAR‑T cells limit PD‑1‑PD‑L1 binding and sustain cytotoxicity to PD‑L1⁺ HCC cells. The relatively low IR expression and differentiation level in double‑target CAR‑T cells in tumour tissues induced tumour‑suppression and extended survival in PD‑L1⁺ HCC TX models, as opposed to their single‑target counterparts. The results of the present study suggested that the newly constructed double‑target CAR‑T cells exhibit stronger tumour‑suppressing effects in HCC than their single‑target counterparts, which are common, suggesting the potential of strengthening CAR‑T cell activity in HCC treatment.

Biomarker discovery and application-An opportunity to resolve the challenge of liver cancer diagnosis and treatment

Liver cancer is one of the most common malignancies, with severe morbidity and mortality. While considerable progress has been made in liver cancer treatment, the 5-year overall survival (OS) of patients has not improved significantly. Reasons include the inadequate capability of early screening and diagnosis, a high incidence of recurrence and metastasis, a high degree of tumor heterogeneity, and an immunosuppressive tumor microenvironment. Therefore, the identification and validation of specific and robust liver cancer biomarkers are of major importance for early screening, timely diagnosis, accurate prognosis, and the prevention of tumor progression. In this review, we highlight some of the latest research progress and potential applications of liver cancer biomarkers, describing hotspots and prospective directions in biomarker discovery.

H-rGO-Pd NPs Nanozyme Enhanced Silver Deposition Strategy for Electrochemical Detection of Glypican-3

Glypican-3 (GPC3), as an emerging biomarker, has been shown to be beneficial for the early diagnosis and treatment of hepatocellular carcinoma (HCC). In this study, an ultrasensitive electrochemical biosensor for GPC3 detection has been constructed based on the hemin-reduced graphene oxide-palladium nanoparticles (H-rGO-Pd NPs) nanozyme-enhanced silver deposition signal amplification strategy. When GPC3 specifically interacted with GPC3 antibody (GPC3_Ab) and GPC3 aptamer (GPC3_Apt), an "H-rGO-Pd NPs-GPC3_Apt/GPC3/GPC3_Ab" sandwich complex was formed with peroxidase-like properties which enhanced H₂O₂ to reduce the silver (Ag) ions in solution to metallic Ag, resulting in the deposition of silver nanoparticles (Ag NPs) on the surface of the biosensor. The amount of deposited Ag, which was derived from the amount of GPC3, was quantified by the differential pulse voltammetry (DPV) method. Under ideal circumstances, the response value was linearly correlated with GPC3 concentration at 10.0-100.0 μg/mL with R² of 0.9715. When the GPC3 concentration was in the range from 0.01 to 10.0 μg/mL, the response value was logarithmically linear with the GPC3 concentration with R² of 0.9941. The limit of detection was 3.30 ng/mL at a signal-to-noise ratio of three and the sensitivity was 1.535 μAμM^-1cm^-2. Furthermore, the electrochemical biosensor detected the GPC3 level in actual serum samples with good recoveries (103.78-106.52%) and satisfactory relative standard deviations (RSDs) (1.89-8.81%), which confirmed the applicability of the sensor in practical applications. This study provides a new analytical method for measuring the level of GPC3 in the early diagnosis of HCC.

Targeting tumor-associated macrophages in hepatocellular carcinoma: biology, strategy, and immunotherapy

Hepatocellular carcinoma (HCC), one of the most malignant tumors, is characterized by its stubborn immunosuppressive microenvironment. As one of the main members of the tumor microenvironment (TME) of HCC, tumor-associated macrophages (TAMs) play a critical role in its occurrence and development, including stimulating angiogenesis, enhancing immunosuppression, and promoting the drug resistance and cancer metastasis. This review describes the origin as well as phenotypic heterogeneity of TAMs and their potential effects on the occurrence and development of HCC and also discusses about various adjuvant therapy based strategies that can be used for targeting TAMs. In addition, we have highlighted different treatment modalities for TAMs based on immunotherapy, including small molecular inhibitors, immune checkpoint inhibitors, antibodies, tumor vaccines, adoptive cellular immunotherapy, and nanocarriers for drug delivery, to explore novel combination therapies and provide feasible therapeutic options for clinically improving the prognosis and quality of life of HCC patients.

Portal vein tumor thrombosis in hepatocellular carcinoma: molecular mechanism and therapy

Portal vein tumor thrombosis (PVTT), a common complication of advanced hepatocellular carcinoma (HCC), remains the bottleneck of the treatments. Liver cancer cells potentially experienced multi-steps during PVTT process, including cancer cells leave from cancer nest, migrate in extracellular matrix, invade the vascular barrier, and colonize in the portal vein. Accumulated evidences have revealed numerous of molecular mechanisms including genetic and epigenetic regulation, cancer stem cells, immunosuppressive microenvironment, hypoxia, et al. contributed to the PVTT formation. In this review, we discuss state-of-the-art PVTT research on the potential molecular mechanisms and experimental models. In addition, we summarize PVTT-associated clinical trials and current treatments for PVTT and suppose perspectives exploring the molecular mechanisms and improving PVTT-related treatment for the future.

A pH-dependent anti-CD47 antibody that selectively targets solid tumors and improves therapeutic efficacy and safety

BACKGROUND

The antiphagocytic molecule CD47 is overexpressed in a wide variety of cancer cells, and antibodies targeting CD47 for cancer therapies are currently under intensive investigation. However, owing to the ubiquitous expression of CD47 on healthy cells, anti-CD47 therapies often achieve only weak therapeutic benefits and can induce severe side effects. Here, we report the generation of a pH-dependent anti-CD47 antibody (BC31M4) which selectively binds to tumors under the acidic solid tumor microenvironment.

METHODS

BC31M4 was generated using antibody phage display and a pH-dependent selection strategy. The pH-dependent binding and blocking activities of BC31M4 were verified using in vitro assays, and the structural basis of the pH-dependent binding property was characterized. BC31M4's antitumor effect was confirmed by both phagocytosis assays and studies in xenograft models. The tumor selectivity, mechanism of action, PK properties, side effects, and therapeutic efficacy were further evaluated in humanized (hCD47 and its receptor hSIRPα) immunocompetent syngeneic mouse models.

RESULTS

The crystal structure reveals that two histidines locate within the CDRs of the light chain directly contribute to the pH-dependent binding of BC31M4. BC31M4 promotes macrophage phagocytosis of tumor cells more potently at acidic-pH than at physiological-pH. Our hCD47/hSIRPα humanized syngeneic mouse model results demonstrated that BC31M4 selectively accumulates in tumors but not in normal tissues. BC31M4 causes minimal side effects and exhibits superior PK properties as compared to the other examined anti-CD47 antibodies. When combined with adoptive T cell transfer, BC31M4 efficiently promotes adaptive immune responses against tumors and also induces immune memory. Moreover, we show that BC31M4's antitumor effects rely on an Fc that mediates strong effector functions.

CONCLUSIONS

Our study illustrates that the development of a tumor-selective, pH-dependent anti-CD47 antibody safely confers strong therapeutic effects against solid tumors, thus providing a promising therapeutic strategy to overcome the challenges of anti-CD47 therapy.

Recent therapeutics in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a malignant tumor of hepatocytes. It is a common malignant tumor of the digestive system that often has initially hidden presentation followed by rapid progression. There are no obvious symptoms in the early stage of HCC. When diagnosed, most patients have locally advanced tumor or distant metastasis; therefore, HCC is difficult to treat and only supportive and symptomatic treatment is adopted. The prognosis is poor and survival time is short. How to effectively treat HCC is important clinically. In recent years, advances in medical technology have resulted in comprehensive treatment methods based on surgery.

Development and Characterization of Nanobody-Derived CD47 Theranostic Pairs in Solid Tumors

Overexpression of CD47 is frequently observed in various types of human malignancies, inhibiting myeloid-mediated elimination of tumor cells and affecting the prognosis of cancer patients. By mapping biomarker expression, immuno-positron emission tomography has been increasingly used for patient screening and response monitoring. By immunization alpacas with recombinant human CD47, we prepared a CD47-targeting nanobody C2 and developed [⁶⁸Ga]Ga-NOTA-C2, followed by an exploration of the diagnostic value in CD47-expressing tumor models including gastric-cancer patient-derived xenograft models. By fusing C2 to an albumin binding domain (ABD), we synthesized ABDC2, which had increased in vivo half-life and improved targeting properties. We further labeled ABDC2 with ⁶⁸Ga/⁸⁹Zr/¹⁷⁷Lu to develop radionuclide theranostic pairs and evaluated the pharmacokinetics and theranostic efficacies of the agents in cell- and patient-derived models. Both C2 and ABDC2 specifically reacted with human CD47 with a high K _D value of 23.50 and 84.57 pM, respectively. [⁶⁸Ga]Ga-NOTA-C2 was developed with high radiochemical purity (99 >%, n = 4) and visualized CD47 expression in the tumors. In comparison to the rapid renal clearance and short half-life of [⁶⁸Ga]Ga-NOTA-C2, both [⁶⁸Ga]Ga-NOTA-ABDC2 and [⁸⁹Zr]Zr-DFO-ABDC2 showed prolonged circulation and increased tumor uptake, with the highest uptake of [⁸⁹Zr]Zr-DFO-ABDC2 occurring at 72 h post-injection. Moreover, [¹⁷⁷Lu]Lu-DOTA-ABDC2 radioimmunotherapy suppressed the tumor growth but was associated with toxicity, warranting further optimization of the treatment schedules. Taken together, we reported a series of nanobody-derived CD47-targeted agents, of which [⁶⁸Ga]Ga-NOTA-C2 and [⁸⁹Zr]Zr-DFO-ABDC2 are readily translatable. Optimization and translation of CD47-targeted theranostic pair may provide new prospects for CD47-targeted management of solid tumors.

Targeting macrophages: a novel treatment strategy in solid tumors

In the tumor microenvironment (TME), tumor-associated macrophages (TAMs) are the most abundant immune cells, which act as a key regulator in tumorigenesis and progression. Increasing evidence have demonstrated that the TME alters the nature of macrophages to maintain dynamic tissue homeostasis, allowing TAMs to acquire the ability to stimulate angiogenesis, promote tumor metastasis and recurrence, and suppress anti-tumor immune responses. Furthermore, tumors with high TAM infiltration have poor prognoses and are resistant to treatment. In the field of solid tumor, the exploration of tumor-promoting mechanisms of TAMs has attracted much attention and targeting TAMs has emerged as a promising immunotherapeutic strategy. Currently, the most common therapeutic options for targeting TAMs are as follows: the deletion of TAMs, the inhibition of TAMs recruitment, the release of phagocytosis by TAMs, and the reprogramming of macrophages to remodel their anti-tumor capacity. Promisingly, the study of chimeric antigen receptor macrophages (CAR-Ms) may provide even greater benefit for patients with solid tumors. In this review, we discuss how TAMs promote the progression of solid tumors as well as summarize emerging immunotherapeutic strategies that targeting macrophages.

Building on the backbone of CD47-based therapy in cancer: Combination strategies, mechanisms, and future perspectives

Described as a "don't eat me" signal, CD47 becomes a vital immune checkpoint in cancer. Its interaction with signal regulatory protein alpha (SIRPα) prevents macrophage phagocytosis. In recent years, a growing body of evidences have unveiled that CD47-based combination therapy exhibits a superior anti-cancer effect. Latest clinical trials about CD47 have adopted the regimen of collaborating with other therapies or developing CD47-directed bispecific antibodies, indicating the combination strategy as a general trend of the future. In this review, clinical and preclinical cases about the current combination strategies targeting CD47 are collected, their underlying mechanisms of action are discussed, and ideas from future perspectives are shared.

Advances in Promoting the Efficacy of Chimeric Antigen Receptor T Cells in the Treatment of Hepatocellular Carcinoma

HCC, one of the most common and deadly cancers worldwide, develops from hepatocytes and accounts for more than 90% of primary liver cancers. The current widely used treatment modalities are far from meeting the needs of liver cancer patients. CAR-T cell therapy, which has recently emerged, has shown promising efficacy in lymphoma and hematologic cancers, but there are still many challenges to overcome in its application to the clinical treatment of HCC, including osmotic barriers, the inhibition of hepatocellular carcinoma microenvironment activity, the limited survival and killing ability of CAR-T cells, and inevitable side effects, among others. As a result, a number of studies have begun to address the suboptimal efficacy of CAR-T cells in HCC, and many of these schemes hold good promise. This review focuses on advances in the past five years aimed at promoting the efficacy of CAR-T cell therapy for treatment of HCC.

Therapeutic Adenovirus Vaccine Combined Immunization with IL-12 Induces Potent CD8+ T Cell Anti-Tumor Immunity in Hepatocellular Carcinoma

Simple Summary

Hepatocellular carcinoma is a kind of tumor with a high malignant degree and mortality rate, and there is no effective treatment method. Currently, immunotherapy has shown good prospects in treating hepatocellular carcinoma. As an important approach of immunotherapy, the vaccine has become an attractive method for tumor treatment. This study developed an adenovirus vaccine containing tumor antigen glypican-3 and adjuvant interleukin 12. The subcutaneous tumor model was intramuscularly immunized three times with vaccines at a ten-day interval. Compared with the control group, the proliferation of CD 8⁺ T cell, the induction of multifunctional CD 8⁺ T cell and dendritic cells, and cytotoxic T lymphocyte activity were significantly increased in the combined immunization group, and the growth of tumor was inhibited obviously. The therapeutic effect of the vaccine of glypican-3 and interleukin 12 mainly depends on the anti-tumor effect of CD 8⁺ T cells mediated by dendritic cells. Likewise, this vaccine also showed a good therapeutic effect in the lung metastasis model of hepatocellular carcinoma. Therefore, the adenovirus vaccine of glypican-3 and interleukin 12 might become a potential way to treat hepatocellular carcinoma.

Abstract

Hepatocellular carcinoma (HCC) is one of the cancers with the highest morbidity and mortality in the world. However, clinical progress in the treatment of HCC has not shown a satisfactory therapeutic effect. Here, we have developed a novel strategy to treat HCC with an adenovirus (Ad)-based vaccine, which contains a specific antigen glypican-3 (GPC3) and an immunostimulatory cytokine IL-12. In the subcutaneous tumor model, Ad-IL-12/GPC3 vaccine was injected into muscles three times to evaluate its therapeutic effect. Compared with the control immunization group, the Ad-IL-12/GPC3 immunization group showed a significant tumor growth inhibition effect, which was confirmed by the reduced tumor volume and the increased tumor inhibition. Ad-IL-12/GPC3 co-immunization promoted the induction and maturation of CD11c⁺ or CD8⁺CD11c⁺ DCs and increased the number of tumor-infiltrating CD8⁺ T cells. Furthermore, in the Ad-IL-12/GPC3 group, the proliferation of CD8⁺ T cells, the induction of multifunctional CD8⁺ T cells, and CTL activity were significantly increased. Interestingly, the deletion of CD8⁺ T cells abolished tumor growth inhibition by Ad-IL-12/GPC3 treatment, suggesting that CD8⁺ T cell immune responses were required to eliminate the tumor. Likewise, Ad-IL-12/GPC3 vaccine also effectively inhibited lung tumor growth or metastasis by enhancing CD8⁺ DCs-mediated multifunctional CD8⁺ T cell immune responses in the lung metastasis model. Therefore, these results indicate that IL-12 combined with Ad-GPC3 vaccine co-immunization might provide a promising therapeutic strategy for HCC patients.

Tumor-associated macrophages in liver cancer: From mechanisms to therapy

Multidimensional analyses have demonstrated the presence of a unique tumor microenvironment (TME) in liver cancer. Tumor-associated macrophages (TAMs) are among the most abundant immune cells infiltrating the TME and are present at all stages of liver cancer progression, and targeting TAMs has become one of the most favored immunotherapy strategies. In addition, macrophages and liver cancer cells have distinct origins. At the early stage of liver cancer, macrophages can provide a niche for the maintenance of liver cancer stem cells. In contrast, cancer stem cells (CSCs) or poorly differentiated tumor cells are key factors modulating macrophage activation. In the present review, we first propose the origin connection between precursor macrophages and liver cancer cells. Macrophages undergo dynamic phenotypic transition during carcinogenesis. In this course of such transition, it is critical to determine the appropriate timing for therapy and block specific markers to suppress pro-tumoral TAMs. The present review provides a more detailed discussion of transition trends of such surface markers than previous reviews. Complex crosstalk occurs between TAMs and liver cancer cells. TAMs play indispensable roles in tumor progression, angiogenesis, and autophagy due to their heterogeneity and robust plasticity. In addition, macrophages in the TME interact with other immune cells by directing cell-to-cell contact or secreting various effector molecules. Similarly, tumor cells combined with other immune cells can drive macrophage recruitment and polarization. Despite the latest achievements and the advancements in treatment strategies following TAMs studies, comprehensive discussions on the communication between macrophages and cancer cells or immune cells in liver cancer are currently lacking. In this review, we discussed the interactions between TAMs and liver cancer cells (from cell origin to maturation), the latest therapeutic strategies (including chimeric antigen receptor macrophages), and critical clinical trials for hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA) to provide a rationale for further clinical investigation of TAMs as a potential target for treating patients with liver cancer.

Preoperative prediction of glypican-3 positive expression in solitary hepatocellular carcinoma on gadoxetate-disodium enhanced magnetic resonance imaging

Purpose

As a coreceptor in Wnt and HGF signaling, glypican-3 (GPC-3) promotes the progression of tumor and is associated with a poor prognosis in hepatocellular carcinoma (HCC). GPC-3 has evolved as a target molecule in various immunotherapies, including chimeric antigen receptor T cell. However, its evaluation still relies on invasive histopathologic examination. Therefore, we aimed to develop an easy-to-use and noninvasive risk score integrating preoperative gadoxetic acid–enhanced magnetic resonance imaging (EOB-MRI) and clinical indicators to predict positive GPC-3 expression in HCC.

Methods and materials

Consecutive patients with surgically-confirmed solitary HCC who underwent preoperative EOB-MRI between January 2016 and November 2021 were retrospectively included. EOB-MRI features were independently evaluated by two masked abdominal radiologists and the expression of GPC-3 was determined by two liver pathologists. On the training dataset, a predictive scoring system for GPC-3 was developed against pathology via logistical regression analysis. Model performances were characterized by computing areas under the receiver operating characteristic curve (AUCs).

Results

A total of 278 patients (training set, n=156; internal validation set, n=39; external validation set, n=83) with solitary HCC (208 [75%] with positive GPC-3 expression) were included. Serum alpha-fetoprotein >10 ng/ml (AFP, odds ratio [OR]=2.3, four points) and five EOB-MR imaging features, including tumor size >3.0cm (OR=0.5, -3 points), nonperipheral “washout” (OR=3.0, five points), infiltrative appearance (OR=9.3, 10 points), marked diffusion restriction (OR=3.3, five points), and iron sparing in solid mass (OR=0.2, -7 points) were significantly associated with positive GPC-3 expression. The optimal threshold of scoring system for predicting GPC-3 positive expression was 5.5 points, with AUC 0.726 and 0.681 on the internal and external validation sets, respectively.

Conclusion

Based on serum AFP and five EOB-MRI features, we developed an easy-to-use and noninvasive risk score which could accurately predict positive GPC-3 HCC, which may help identify potential responders for GPC-3-targeted immunotherapy.

CD47 as a promising therapeutic target in oncology

CD47 is ubiquitously expressed on the surface of cells and plays a critical role in self-recognition. By interacting with SIRPα, TSP-1 and integrins, CD47 modulates cellular phagocytosis by macrophages, determines life span of individual erythrocytes, regulates activation of immune cells, and manipulates synaptic pruning during neuronal development. As such, CD47 has recently be regarded as one of novel innate checkpoint receptor targets for cancer immunotherapy. In this review, we will discuss increasing awareness about the diverse functions of CD47 and its role in immune system homeostasis. Then, we will discuss its potential therapeutic roles against cancer and outlines, the possible future research directions of CD47- based therapeutics against cancer.

Targeting the CD47-SIRPα Innate Immune Checkpoint to Potentiate Antibody Therapy in Cancer by Neutrophils

Simple Summary

Immunotherapy aims to engage various immune cells in the elimination of cancer cells. Neutrophils are the most abundant leukocytes in the circulation and have unique mechanisms by which they can kill cancer cells opsonized by antibodies. However, neutrophil effector functions are limited by the inhibitory receptor SIRPα, when it interacts with CD47. The CD47 protein is expressed on all cells in the body and acts as a ‘don’t eat me’ signal to prevent tissue damage. Cancer cells can express high levels of CD47 to circumvent tumor elimination. Thus, blocking the interaction between CD47 and SIRPα may enhance anti-tumor effects by neutrophils in the presence of tumor-targeting monoclonal antibodies. In this review, we discuss CD47-SIRPα as an innate immune checkpoint on neutrophils and explore the preliminary results of clinical trials using CD47-SIRPα blocking agents.

Abstract

In the past 25 years, a considerable number of therapeutic monoclonal antibodies (mAb) against a variety of tumor-associated antigens (TAA) have become available for the targeted treatment of hematologic and solid cancers. Such antibodies opsonize cancer cells and can trigger cytotoxic responses mediated by Fc-receptor expressing immune cells in the tumor microenvironment (TME). Although frequently ignored, neutrophils, which are abundantly present in the circulation and many cancers, have demonstrated to constitute bona fide effector cells for antibody-mediated tumor elimination in vivo. It has now also been established that neutrophils exert a unique mechanism of cytotoxicity towards antibody-opsonized tumor cells, known as trogoptosis, which involves Fc-receptor (FcR)-mediated trogocytosis of cancer cell plasma membrane leading to a lytic/necrotic type of cell death. However, neutrophils prominently express the myeloid inhibitory receptor SIRPα, which upon interaction with the ‘don’t eat me’ signal CD47 on cancer cells, limits cytotoxicity, forming a mechanism of resistance towards anti-cancer antibody therapeutics. In fact, tumor cells often overexpress CD47, thereby even more strongly restricting neutrophil-mediated tumor killing. Blocking the CD47-SIRPα interaction may therefore potentiate neutrophil-mediated antibody-dependent cellular cytotoxicity (ADCC) towards cancer cells, and various inhibitors of the CD47-SIRPα axis are now in clinical studies. Here, we review the role of neutrophils in antibody therapy in cancer and their regulation by the CD47-SIRPα innate immune checkpoint. Moreover, initial results of CD47-SIRPα blockade in clinical trials are discussed.

Advances in the study of CD47-based bispecific antibody in cancer immunotherapy

Tumor therapy has entered the era of immunotherapy. Monoclonal antibodies (mAb), immune checkpoint inhibitors, chimeric antigen receptor T-cell (CAR-T), cytokine-induced killer (CIK)，tumor-infiltrating lymphocytes (TIL) and other cellular immunotherapies have become the focus of current research. The CD47/SIRPα target is becoming another popular tumor immunotherapy target following the PDCD1/CD247(PD1/PD-L1) checkpoint inhibitor. In recent years, a large number of CD47/SIRPα mAbs, fusion proteins, and CD47/SIRPα-based bispecific antibodies (BsAbs) are undergoing preclinical and clinical trials and have good curative effects in the treatment of hematological tumors and solid tumors. They bring new vitality and hope for the treatment of patients with advanced tumors. This review summarizes the research progress of CD47/SIRPα-based BsAbs with different targets for tumor treatment. There are 12 and 9 BsAbs in clinical trials and pre-clinical research, respectively. We report on the mechanism of 15 BsAb molecules with different target and analyze the efficacy and safety of preclinical and clinical trials, discuss the issues that may be faced in the development of CD47-based BsAbs, and dual target molecules, and summarize their development prospects. This review provides a reference for the safety and effectiveness of BsAbs in clinical application and in the future development of antibodies.

Glypican-3: A Novel and Promising Target for the Treatment of Hepatocellular Carcinoma

Glypican-3 (GPC3) is a membrane-associated proteoglycan that is specifically up-regulated in hepatocellular carcinoma (HCC) although rarely or not expressed in normal liver tissues, making it a perfect diagnostic and treatment target for HCC. Several GPC3-based clinical trials are ongoing and recently several innovative GPC3-targeted therapeutic methods have emerged with exciting results, including GPC3 vaccine, anti-GPC3 immunotoxin, combined therapy with immune checkpoint blockades (ICBs), and chimeric antigen receptor (CAR) T or NK cells. Here, we review the value of GPC3 in the diagnosis and prognosis of HCC, together with its signaling pathways, with a specific focus on GPC3-targeted treatments of HCC and some prospects for the future GPC3-based therapeutic strategies in HCC.

Far-Red Light Triggered Production of Bispecific T Cell Engagers (BiTEs) from Engineered Cells for Antitumor Application

Bispecific T-cell engagers (BiTEs), which have shown potent antitumor activity in humans, are emerging as one of the most promising immunotherapeutic strategies for cancer treatment in recent years. However, the clinical application of BiTEs nowadays has been hampered by their short half-life in the circulatory system due to their low molecular weight and rapid renal clearance. Inevitable continuous infusion of BiTEs has become a routine operation in order to achieve effective treatment, although it is costly, inconvenient, time-consuming, and even painful for patients in some cases. To develop an on-demand, tunable, and reversible approach to overcome these limitations, we assembled a transcription-control device into mammalian cells based on a bacterial far-red light (FRL) responsive signaling pathway to drive the expression of a BiTE against Glypican 3 (GPC3), which is a highly tumor-specific antigen expressed in most hepatocellular carcinomas (HCC). As demonstrated in in vitro experiments, we proved that the FRL sensitive device spatiotemporally responded to the control of FRL illumination and produced a therapeutic level of BiTEs that recruited and activated human T cells to eliminate GPC3 positive tumor cells. By functionally harnessing the power of optogenetics to remotely regulate the production of BiTEs from bioengineered cells and demonstrating its effectiveness in treating tumor cells, this study provides a novel approach to achieve an in vivo supply of BiTEs, which could be potentially applied to other formats of bispecific antibodies and facilitate their clinical applications.

Combination of Ablation and Immunotherapy for Hepatocellular Carcinoma: Where We Are and Where to Go

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide and is increasing in incidence. Local ablative therapy plays a leading role in HCC treatment. Radiofrequency (RFA) is one of the first-line therapies for early local ablation. Other local ablation techniques (e.g., microwave ablation, cryoablation, irreversible electroporation, phototherapy.) have been extensively explored in clinical trials or cell/animal studies but have not yet been established as a standard treatment or applied clinically. On the one hand, single treatment may not meet the needs. On the other hand, ablative therapy can stimulate local and systemic immune effects. The combination strategy of immunotherapy and ablation is reasonable. In this review, we briefly summarized the current status and progress of ablation and immunotherapy for HCC. The immune effects of local ablation and the strategies of combination therapy, especially synergistic strategies based on biomedical materials, were discussed. This review is hoped to provide references for future researches on ablative immunotherapy to arrive to a promising new era of HCC treatment.

Combination Therapy of Hepatocellular Carcinoma by GPC3-Targeted Bispecific Antibody and Irinotecan is Potent in Suppressing Tumor Growth in Mice

Hepatocellular carcinoma (HCC) is a world leading cause of cancer-related mortality, and currently no curative treatment for advanced HCC is available. Glypican-3 (GPC3) is an attractive target for HCC immunotherapy. This study explored the efficacy of six GPC3-targeted bispecific antibodies, alone or in combination with chemotherapeutic drug Irinotecan, for the treatment of HCC. The bispecific antibodies were constructed using three different structures, knob-into-hole (KH), scFv-scFv-hFc, and scFv-hFc-scFv, where CD3-targeting mAb OKT3 (scFv) was paired with two representative GPC3 mAbs hYP7 (scFv) and HN3 (VH only) that target different epitopes. The In vitro cell killing assay revealed that all bispecific antibodies efficiently killed GPC3 positive cancer cells, with hYP7-KH, hYP7-OKT3-hFc, and HN3-KH being most potent. In vivo xenograft mouse studies demonstrated that all bispecific antibodies suppressed tumor growth similarly, with hYP7-OKT3-hFc performing slightly better. Combination of hYP7-OKT3-hFc with Irinotecan dramatically improved the efficacy and arrested tumor growth of HepG2, Hep3B, and G1 in xenograft mice. Our results demonstrated that the cell surface proximal bispecific antibody hYP7-OKT3-hFc was superior in terms of potency and the GPC3-targeted bispecific antibody combined with Irinotecan was much potent to control HCC growth.

A miR-212-3p/SLC6A1 Regulatory Sub-Network for the Prognosis of Hepatocellular Carcinoma

Introduction

Hepatocellular carcinoma (HCC) is a liver cancer with a poor prognosis. Owing to the complexity and limited pathogenic mechanism research on HCC, the molecular targeted therapy has been hindered.

Methods

In this study, we categorized transcriptome data into low-Myc and high-Myc expression groups in 365 HCC samples, screened the differentially expressed RNAs, including 441 DE-lncRNAs, 99 DE-miRNAs and 612 DE-mRNAs, constructed a lncRNA-miRNA-mRNA regulatory network, and selected a hub triple regulatory network through cytoHubba analysis. Through Gene ontology and KEGG pathway, a hub regulatory network was particularly enriched in the “Wnt signaling pathway” and “Cytochrome P450-arranged by substrate type” by Metascape. The prognostic genes in the hub regulatory network were evaluated by the RNA expression analysis, Kaplan–Meier (KM) survival analysis, and correlation analysis.

Results

The results showed that miR-212-3p/SLC6A1 axis was a potential prognostic model for HCC. Furthermore, IHC analysis showed down-regulated expression of SLC6A1 in HCC tissues and Alb-Cre;Myc mouse liver cancer tissues. The genetics and epigenetic analysis indicated that SLC6A1 expression was negatively correlated with DNA methylation. Immune infiltration analysis showed a negative relation between SLC6A1 and T cell exhaustion/monocyte in liver cancer tissues.

Conclusion

In summary, the study revealed that miR-212-3p/SLC6A1 axis could serve as a crucial therapeutic target for HCC.

Bioassay Development for Bispecific Antibodies-Challenges and Opportunities

Antibody therapeutics are expanding with promising clinical outcomes, and diverse formats of antibodies are further developed and available for patients of the most challenging disease areas. Bispecific antibodies (BsAbs) have several significant advantages over monospecific antibodies by engaging two antigen targets. Due to the complicated mechanism of action, diverse structural variations, and dual-target binding, developing bioassays and other types of assays to characterize BsAbs is challenging. Developing bioassays for BsAbs requires a good understanding of the mechanism of action of the molecule, principles and applications of different bioanalytical methods, and phase-appropriate considerations per regulatory guidelines. Here, we review recent advances and case studies to provide strategies and insights for bioassay development for different types of bispecific molecules.

Advances in drug development for hepatocellular carcinoma: clinical trials and potential therapeutic targets

Although hepatocellular carcinoma (HCC) is one of the deadliest health burdens worldwide, few drugs are available for its clinical treatment. However, in recent years, major breakthroughs have been made in the development of new drugs due to intensive fundamental research and numerous clinical trials in HCC. Traditional systemic therapy schemes and emerging immunotherapy strategies have both advanced. Between 2017 and 2020, the United States Food and Drug Administration (FDA) approved a variety of drugs for the treatment of HCC, including multikinase inhibitors (regorafenib, lenvatinib, cabozantinib, and ramucirumab), immune checkpoint inhibitors (nivolumab and pembrolizumab), and bevacizumab combined with atezolizumab. Currently, there are more than 1000 ongoing clinical trials involving HCC, which represents a vibrant atmosphere in the HCC drug research and development field. Additionally, traditional Chinese medicine approaches are being gradually optimized. This review summarizes FDA-approved agents for HCC, elucidates promising agents evaluated in clinical phase I/II/III trials and identifies emerging targets for HCC treatment. In addition, we introduce the development of HCC drugs in China. Finally, we discuss potential problems in HCC drug therapy and possible future solutions and indicate future directions for the development of drugs for HCC treatment.