Anti-PD-L1/TGF-βR fusion protein (SHR-1701) overcomes disrupted lymphocyte recovery-induced resistance to PD-1/PD-L1 inhibitors in lung cancer

A review of the immunomodulatory properties of mesenchymal stem cells and their derived extracellular vesicles in small-cell and non-small-cell lung cancer cells

Among the most challenging diseases to treat is lung cancer (LC). While immunotherapy has a checkered history, it has lately shown great promise in the treatment of LC, and interest in this promising new approach is on the rise around the globe. Immunotherapy using mesenchymal stem cells (MSCs) is gaining popularity. Regenerative medicine, cell therapy, and immune modulation are three areas that have shown significant interest in MSCs. More than that, MSCs have recently attracted attention as potential anti-cancer drug delivery vehicles due to their inherent ability to go home to tumor locations. Making MSCs a double-edged sword in the fight against neoplastic illnesses, they are also known to impart pro-oncogenic properties. Additionally, multiple studies have proposed extracellular vesicles (EVs) secreted by MSCs as a potential therapeutic agent or method for delivering anti-cancer drugs. However, there has been conflicting evidence regarding the impact of MSCs or MSC-EV on the behavior of cancer cells, and the exact mechanism for this effect is still unknown. Our research has focused on MSCs and their key characteristics, such as their immunomodulatory capabilities for cancer therapy. Our research has also explored the potential of MSCs and their derivatives to treat small-cell and non-small-cell lung cancers (NSCLC and SCLC, respectively) by leveraging MSCs' immunomodulatory characteristics. At the end of this article, we covered the pros and cons of this therapy procedure, as well as what researchers want to do in the future to make it more suitable for clinical application in LC treatment.

Cancer-associated fibroblasts as therapeutic targets for cancer: advances, challenges, and future prospects

Research into cancer treatment has been mainly focused on developing therapies to directly target cancer cells. Over the past decade, extensive studies have revealed critical roles of the tumour microenvironment (TME) in cancer initiation, progression, and drug resistance. Notably, cancer-associated fibroblasts (CAFs) have emerged as one of the primary contributors in shaping TME, creating a favourable environment for cancer development. Many preclinical studies have identified promising targets on CAFs, demonstrating remarkable efficacy of some CAF-targeted treatments in preclinical models. Encouraged by these compelling findings, therapeutic strategies have now advanced into clinical evaluation. We aim to provide a comprehensive review of relevant subjects on CAFs, including CAF-related markers and targets, their multifaceted roles, and current landscape of ongoing clinical trials. This knowledge can guide future research on CAFs and advocate for clinical investigations targeting CAFs.

Decoding the complex web: Cellular and molecular interactions in the lung tumor microenvironment

The lung tumor microenvironment (TME) or stroma is a dynamic space of numerous cells and their released molecules. This complicated web regulates tumor progression and resistance to different modalities. Lung cancer cells in conjunction with their stroma liberate a wide range of factors that dampen antitumor attacks by innate immunity cells like natural killer (NK) cells and also adaptive responses by effector T cells. These factors include numerous growth factors, exosomes and epigenetic regulators, and also anti-inflammatory cytokines. Understanding the intricate interactions between tumor cells and various elements within the lung TME, such as immune and stromal cells can help provide novel strategies for better management and treatment of lung malignancies. The current article discusses the complex network of cells and signaling molecules, which mediate communications in lung TME. By elucidating these multifaceted interactions, we aim to provide insights into potential therapeutic targets and strategies for lung cancer treatment.

Tumor-infiltrating regulatory T cell: A promising therapeutic target in tumor microenvironment

ABSTRACT

Regulatory T cell (Tregs) predominantly maintain the immune balance and prevent autoimmunity via their immunosuppressive functions. However, tumor-infiltrating Tregs (TI-Tregs) may mediate tumor immune tolerance in complex tumor microenvironments, resulting in poor prognosis. Distinguishing specific TI-Treg subpopulations from peripheral Tregs and intratumoral conventional T cells (Tconvs) has recently emerged as an important topic in antitumor therapy. In this review, we summarize novel therapeutic approaches targeting both the metabolic pathways and hallmarks of TI-Tregs in preclinical and clinical studies. Although the phenotypic and functional diversity of TI-Tregs remains unclear, our review provides new insights into TI-Treg-based therapies and facilitates precision medicine for tumor treatment.

Clinical and biomarker analyses of SHR-1701 combined with famitinib in patients with previously treated advanced biliary tract cancer or pancreatic ductal adenocarcinoma: a phase II trial

Advanced biliary tract cancer (BTC) and pancreatic ductal adenocarcinoma (PDAC) have poor prognoses and limited treatment options. Here, we conducted this first-in-class phase II study to evaluate the efficacy and safety of SHR-1701, a bifunctional fusion protein targeting programmed death-ligand 1 (PD-L1) and transforming growth factor-beta (TGF-β), combined with famitinib, a multi-targeted receptor tyrosine kinase inhibitor, in patients with advanced BTC or PDAC who failed previous standard treatment (trial registration: ChiCTR2000037927). Among 51 enrolled patients, the BTC cohort showed an objective response rate (ORR) of 28% (including 2 complete responses) and a disease control rate (DCR) of 80%, with a median progression-free survival (mPFS) of 5.1 months and a median overall survival (mOS) of 16.0 months. In the PDAC cohort, the ORR was 15% (2 complete responses), with a DCR of 60%, and the mPFS and mOS were 2.1 months and 5.3 months, respectively. Grade 3 or 4 treatment-related adverse events (TRAEs) occurred in 29.4% of patients, with no grade 5 TRAEs reported. Exploratory analyses revealed that primary tumor resection history, peripheral blood immunophenotype changes, and distinct immune-metabolic profiles were associated with treatment benefits. An immune/metabolism score integrating the features of six genes was developed as a predictive biomarker for immunotherapy response in multiple cohorts, allowing for the selection of patients most likely to experience positive outcomes from this therapy regimen. In conclusion, our study provides proof-of-concept data supporting the potential of SHR-1701 plus famitinib as an effective and safe subsequent-line therapy for refractory BTC and PDAC, highlighting the promise of targeting PD-L1, TGF-β, and angiogenesis pathways simultaneously.

Bispecific therapeutics: a state-of-the-art review on the combination of immune checkpoint ‎inhibition with costimulatory and non-checkpoint targeted therapy

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have revolutionized the field of cancer immunotherapy and have enhanced the survival of patients with malignant tumors. However, the overall efficacy of ICIs remains unsatisfactory and is faced with two major concerns of resistance development and occurrence of immune-related adverse events (irAEs). Bispecific antibodies (bsAbs) have emerged as promising strategies with unique mechanisms of action to achieve a better efficacy and safety than monoclonal antibodies (mAbs) or even their combination. BsAbs along with other bispecific platforms such as bispecific fusion proteins, nanobodies, and CAR-T cells may help to avoid development of resistance and reduce irAEs caused by on-target/off-tumor binding effects of mAbs.

AREAS COVERED

A literature search was performed using PubMed for English-language articles to provide a comprehensive overview of preclinical and clinical studies on bsAbs specified for both immune checkpoints and non-checkpoint molecules as a well-enhanced class of therapeutics.

EXPERT OPINION

Identifying suitable targets and selecting effective engineering platforms enhance the potential of bsAbs to address the challenges associated with conventional therapies such as ICIs, positioning them as a promising class of therapeutics in the landscape of cancer immunotherapy.

The endometrial cancer A230V-ALK5 (TGFBR1) mutant attenuates TGF-β signaling and exhibits reduced in vitro sensitivity to ALK5 inhibitors

The ALK5 (TGFBR1) receptor serine/threonine kinase transduces TGF-β (Transforming Growth Factor beta) signaling to activate SMAD2/3-dependent and -independent pathways. Here, we aimed to determine the functional consequences of ALK5 mutations in human endometrial cancer (EC). Somatic mutation data were retrieved from publicly available databases. Using seven in silico algorithms, 78.5% (11 of 14) of ALK5 kinase domain mutations in EC, including A230V-ALK5, were predicted to impact protein function. For in vitro studies, we focused on A230V-ALK5 because it was the only mutated residue located within the ATP-binding pocket, which is an important region for both ATP-binding and binding of ATP-competitive inhibitors. Constructs expressing wildtype-, constitutively-active-, kinase-dead-, or mutant A230V-ALK5, were transfected into NIH/3T3 cells. Following TGF-β1 stimulation, transient exogenous expression of A230V-ALK5 resulted in attenuated SMAD2/3 signal transduction and reduced AKT activation. We further showed that the A230V-ALK5 mutant had reduced stability resulting from increased ubiquitin-dependent protein degradation. Our structural modeling predicted that SB-431542, a small molecule ATP-competitive inhibitor of ALK5, binds to the A230V-ALK5 mutant with reduced affinity compared to wildtype-ALK5. We therefore examined the inhibitory effect of SB-431542 and galunisertib on wildtype- and mutant-ALK5 activity using a Smad-binding element (SBE) luciferase reporter assay combined with TGF-β1 stimulation, in NIH/3T3 cells and HEC-265 EC cells. SBE luciferase activity in A230V-ALK5 transfected cells was inhibited less by SB-431542 and galunisertib than in wildtype-ALK5 transfected cells indicating that A230V-ALK5 is less sensitive to inhibition by these agents than wildtype-ALK5, potentially due to changes in SB-431542/A230V-ALK5 binding affinity. Our findings are novel and show that A230V-ALK5 is a partial loss-of-function mutant that attenuates TGF-β1 signal transduction and has reduced sensitivity to ALK5 small molecule inhibitors.

Clinical and immunological characteristics of high-risk double-hit multiple myeloma

At present, the characteristics of double-hit multiple myeloma (DHMM) are unknown. We retrospectively analyzed the clinical data from 433 new diagnosed MM patients and found that DHMM have a higher β2-MG level and percentage of bone marrow plasma cell. Cox regression analysis showed that the prognosis of DHMM was not limited by clinical indicators. The abnormal proliferation of bone marrow in DHMM is obvious, and the proportion of poorly differentiated plasma cell is high. By collecting specimens from our center and performing flow cytometry to analyze the immunophenotypic and functional characteristics of lymphocyte subpopulations, we found that DHMM had a higher ratio of Tregs cells, and the proportion of iTregs cells was also significantly higher than non-DHMM (P < 0.05). Moreover, DHMM had higher levels of TGF-β1 and IL-10, and TGF-β1 and IL-10 were positively correlated with iTregs (P < 0.05). In addition, DHMM was highly expressed PD-1 on CD8 + T cells and had a higher proportion of CD38highTregs cells. In vitro we have shown that the addition of TGF-β1 antibody or CD38 antibody can effectively inhibit the proportion of CD38high Tregs. This study describes the characteristics of DHMM based on bicentric data, which is helpful to better provide theoretical support for the treatment of DHMM.

Blockade of CCR5+ T Cell Accumulation in the Tumor Microenvironment Optimizes Anti-TGF-β/PD-L1 Bispecific Antibody

In the previous studies, anti-TGF-β/PD-L1 bispecific antibody YM101 is demonstrated, with superior efficacy to anti-PD-L1 monotherapy in multiple tumor models. However, YM101 therapy can not achieve complete regression in most tumor-bearing mice, suggesting the presence of other immunosuppressive elements in the tumor microenvironment (TME) beyond TGF-β and PD-L1. Thoroughly exploring the TME is imperative to pave the way for the successful translation of anti-TGF-β/PD-L1 BsAb into clinical practice. In this work, scRNA-seq is employed to comprehensively profile the TME changes induced by YM101. The scRNA-seq analysis reveals an increase in immune cell populations associated with antitumor immunity and enhances cell-killing pathways. However, the analysis also uncovers the presence of immunosuppressive CCR5+ T cells in the TME after YM101 treatment. To overcome this hurdle, YM101 is combined with Maraviroc, a widely used CCR5 antagonist for treating HIV infection, suppressing CCR5+ T cell accumulation, and optimizing the immune response. Mechanistically, YM101-induced neutrophil activation recruits immunosuppressive CCR5+ T cells via CCR5 ligand secretion, creating a feedback loop that diminishes the antitumor response. Maraviroc then cleared these infiltrating cells and offset YM101-mediated immunosuppressive effects, further unleashing the antitumor immunity. These findings suggest selectively targeting CCR5 signaling with Maraviroc represents a promising and strategic approach to enhance YM101 efficacy.

Targeting extracellular matrix interaction in gastrointestinal cancer: Immune modulation, metabolic reprogramming, and therapeutic strategies

The extracellular matrix (ECM) is a major constituent of the tumor microenvironment, acting as a mediator that supports the progression of gastrointestinal (GI) cancers, particularly in mesenchymal subtypes. Beyond providing structural support, the ECM actively shapes the tumor microenvironment (TME) through complex biochemical and biomechanical remodeling. Dysregulation of ECM composition and signaling is closely linked to increased cancer aggressiveness, poor prognosis, and resistance to therapy. ECM components, such as collagen, fibronectin, laminin, and periostin, influence tumor growth, metastasis, immune modulation, and metabolic reprogramming by interacting with tumor cells, immune cells, and cancer-associated fibroblasts. In this review, we highlight the heterogeneous nature of the ECM and the dualistic roles of its components across GI cancers, with a focus on their contributions to immune evasion and metabolic remodeling via intercellular interactions. Additionally, we explore therapeutic strategies targeting ECM remodeling and ECM-centered interactions, emphasizing their potential in enhancing existing anti-tumor therapies.

Transforming growth factor-β micro-environment mediated immune cell functions in cervical cancer

Propensity to develop cervical cancer (CC) in human papilloma virus (HPV) infected individual could potentially involve the impaired immune functioning. Several stages of HPV surveillance by immune cells in tumor micro-environment (TME) is regulated mainly by transforming growth factor-beta (TGF-β) and is crucial for the establishment of CC. The role of TGF-β in the initiation and progression of CC is very complex and involve different suppressor of mothers against decapentaplegic homolog (SMAD) dependent and SMAD independent signaling mechanism(s). This review summarizes the handling of HPV by immune cells such as T lymphocytes, B lymphocytes, natural killer cells (NK), dendritic cells (DC), monocytes, macrophages, myeloid derived suppressor cells (MDSC) and their regulation by TGF-β. The hijack mechanisms adapted by HPV to evade this surveillance process is discussed. Biomarkers indicating the stages of CC and immune checkpoints that can be targeted for improved outcome are included for immune-based theragnostics. This review also addresses the direct actions of TGF-β on CC cells and tumor/immune cell interactions. Therapies focused on targeting TGF-β using small molecule inhibitors, monoclonal antibodies and TGF-β chimeric antigen receptor (CAR)T cells are collated to understand the current strategies related to TGF-β in the management of CC.

Therapeutic targeting of TGF-β in lung cancer

Transforming growth factor-β (TGF-β) plays a complex role in lung cancer pathophysiology, initially acting as a tumor suppressor by inhibiting early-stage tumor growth. However, its role evolves in the advanced stages of the disease, where it contributes to tumor progression not by directly promoting cell proliferation but by enhancing epithelial-mesenchymal transition (EMT) and creating a conducive tumor microenvironment. While EMT is typically associated with enhanced migratory and invasive capabilities rather than proliferation per se, TGF-β's influence on this process facilitates the complex dynamics of tumor metastasis. Additionally, TGF-β impacts the tumor microenvironment by interacting with immune cells, a process influenced by genetic and epigenetic changes within tumor cells. This interaction highlights its role in immune evasion and chemoresistance, further complicating lung cancer therapy. This review provides a critical overview of recent findings on TGF-β's involvement in lung cancer, its contribution to chemoresistance, and its modulation of the immune response. Despite the considerable challenges encountered in clinical trials and the development of new treatments targeting the TGF-β pathway, this review highlights the necessity for continued, in-depth investigation into the roles of TGF-β. A deeper comprehension of these roles may lead to novel, targeted therapies for lung cancer. Despite the intricate behavior of TGF-β signaling in tumors and previous challenges, further research could yield innovative treatment strategies.

Neoadjuvant SHR-1701 with or without chemotherapy in unresectable stage III non-small-cell lung cancer: A proof-of-concept, phase 2 trial

We conducted a proof-of-concept, phase 2 trial to assess neoadjuvant SHR-1701 with or without chemotherapy, followed by surgery or radiotherapy, and then consolidation SHR-1701 in unresectable stage III non-small-cell lung cancer (NSCLC). In the primary cohort of patients receiving neoadjuvant combination therapy (n = 97), both primary endpoints were met, with a post-induction objective response rate of 58% (95% confidence interval [CI] 47-68) and an 18-month event-free survival (EFS) rate of 56.6% (95% CI 45.2-66.5). Overall, 27 (25%) patients underwent surgery; all achieved R0 resection. Among them, 12 (44%) major pathological responses and seven (26%) pathological complete responses were recorded. The 18-month EFS rate was 74.1% (95% CI 53.2-86.7) in surgical patients and 57.3% (43.0-69.3) in radiotherapy-treated patients. Neoadjuvant SHR-1701 with chemotherapy, followed by surgery or radiotherapy, showed promising efficacy with a tolerable safety profile in unresectable stage III NSCLC. Surgical conversion was feasible in a notable proportion of patients and associated with better survival outcomes.

Prognostic significance of peripheral and tumor-infiltrating lymphocytes in newly diagnosed stage III/IV non-small-cell lung cancer

Background and aim

Lymphocytes are effector cells that fight cancer by killing tumor cells. Here, we aim to explore the prognostic significance of both peripheral and tumor-infiltrating lymphocytes (TILs) in newly diagnosed stage III/IV non-small-cell lung cancer (NSCLC).

Materials and methods

In total, 105 cases of newly diagnosed stage III/IV NSCLC from July 2017 to October 2022 at the Tianjin Beichen Hospital were retrospectively investigated. Peripheral blood samples at the time of diagnosis and tumor tissue slices from these patients were collected. General peripheral blood cell composition and TILs were measured and analyzed via an automatic blood analyzer and immunofluorescence staining analysis. The overall survival (OS) time of all patients was also obtained and analyzed.

Results

The median overall survival (mOS) of all patients is 12 months. The 1-, 2-, and 3-year overall survival rates were 60.5, 28.4, and 18.6%, respectively. Peripheral lymphocyte and neutrophil percentages, serum C-reactive protein (CRP) expression, tumor size, and tumor pathology are the prognostic factors of OS for newly diagnosed stage III/IV NSCLC patients. Moreover, patients with high tumor CD4+ and CD8+ T cell infiltration survived significantly longer compared to patients with low tumor CD4+ and CD8+ T cell infiltration (p < 0.0001 and p = 0.011, respectively). Compared to low tumor CD33+ cell infiltration, high tumor CD33+ cell infiltration was associated with worse OS (p = 0.018). High tumor CD8+ T cell infiltration was associated with lower peripheral lymphocyte number, lower serum CRP expression, smaller tumor size, and better tumor pathology (p = 0.012, p = 0.040, p = 0.012, and p = 0.029, respectively).

Conclusion

Increased numbers of peripheral lymphocytes, CD33+ cells, CD4+ TILs, and CD8+ TILs were significantly associated with OS in newly diagnosed stage III/IV NSCLC patients, which were positively associated with several basic clinical factors.

Advances and Challenges in Targeting TGF-β Isoforms for Therapeutic Intervention of Cancer: A Mechanism-Based Perspective

The TGF-β family is a group of 25 kDa secretory cytokines, in mammals consisting of three dimeric isoforms (TGF-βs 1, 2, and 3), each encoded on a separate gene with unique regulatory elements. Each isoform plays unique, diverse, and pivotal roles in cell growth, survival, immune response, and differentiation. However, many researchers in the TGF-β field often mistakenly assume a uniform functionality among all three isoforms. Although TGF-βs are essential for normal development and many cellular and physiological processes, their dysregulated expression contributes significantly to various diseases. Notably, they drive conditions like fibrosis and tumor metastasis/progression. To counter these pathologies, extensive efforts have been directed towards targeting TGF-βs, resulting in the development of a range of TGF-β inhibitors. Despite some clinical success, these agents have yet to reach their full potential in the treatment of cancers. A significant challenge rests in effectively targeting TGF-βs' pathological functions while preserving their physiological roles. Many existing approaches collectively target all three isoforms, failing to target just the specific deregulated ones. Additionally, most strategies tackle the entire TGF-β signaling pathway instead of focusing on disease-specific components or preferentially targeting tumors. This review gives a unique historical overview of the TGF-β field often missed in other reviews and provides a current landscape of TGF-β research, emphasizing isoform-specific functions and disease implications. The review then delves into ongoing therapeutic strategies in cancer, stressing the need for more tools that target specific isoforms and disease-related pathway components, advocating mechanism-based and refined approaches to enhance the effectiveness of TGF-β-targeted cancer therapies.

Combination of T cell-redirecting strategies with a bispecific antibody blocking TGF-β and PD-L1 enhances antitumor responses

T cell-based immunotherapies for solid tumors have not achieved the clinical success observed in hematological malignancies, partially due to the immunosuppressive effect promoted by the tumor microenvironment, where PD-L1 and TGF-β play a pivotal role. However, durable responses to immune checkpoint inhibitors remain limited to a minority of patients, while TGF-β inhibitors have not reached the market yet. Here, we describe a bispecific antibody for dual blockade of PD-L1 and TFG-β, termed AxF (scFv)2, under the premise that combination with T cell redirecting strategies would improve clinical benefit. The AxF (scFv)2 antibody was well expressed in mammalian and yeast cells, bound both targets and inhibited dose-dependently the corresponding signaling pathways in luminescence-based cellular reporter systems. Moreover, combined treatment with trispecific T-cell engagers (TriTE) or CAR-T cells significantly boosted T cell activation status and cytotoxic response in breast, lung and colorectal (CRC) cancer models. Importantly, the combination of an EpCAMxCD3×EGFR TriTE with the AxF (scFv)2 delayed CRC tumor growth in vivo and significantly enhanced survival compared to monotherapy with the trispecific antibody. In summary, we demonstrated the feasibility of concomitant blockade of PD-L1 and TGF-β by a single molecule, as well as its therapeutic potential in combination with different T cell redirecting agents to overcome tumor microenvironment-mediated immunosuppression.

Tumor-associated macrophages in non-small-cell lung cancer: From treatment resistance mechanisms to therapeutic targets

Non-small cell lung cancer (NSCLC) remains one of the leading causes of cancer-related deaths worldwide. Different treatment approaches are typically employed based on the stage of NSCLC. Common clinical treatment methods include surgical resection, drug therapy, and radiation therapy. However, with the introduction and utilization of immune checkpoint inhibitors, cancer treatment has entered a new era, completely revolutionizing the treatment landscape for various cancers and significantly improving overall patient survival. Concurrently, treatment resistance often poses a critical challenge, with many patients experiencing disease progression following an initial response due to treatment resistance. Increasing evidence suggests that the tumor microenvironment (TME) plays a pivotal role in treatment resistance. Tumor-associated macrophages (TAMs) within the TME can promote treatment resistance in NSCLC by secreting various cytokines activating signaling pathways, and interacting with other immune cells. Therefore, this article will focus on elucidating the key mechanisms of TAMs in treatment resistance and analyze how targeting TAMs can reduce the levels of treatment resistance in NSCLC, providing a comprehensive understanding of the principles and approaches to overcome treatment resistance in NSCLC.

Dual immunotherapy in advanced or metastatic non-small cell lung cancer: A network meta-analysis

Objectives

Recently, there has been extensive research on dual immunotherapy for advanced or metastatic non-small cell lung cancer (NSCLC), yet a comprehensive evaluation is lacking. This study aimed to rank the available treatment options and assess the efficacy and safety of dual immunotherapy regimens through the implementation of a Bayesian network meta-analysis (NMA).

Materials and methods

A thorough search was conducted to recognize eligible randomized controlled trials (RCTs) on March 20, 2023. Overall survival (OS), progression-free survival (PFS), treatment-related adverse events (TRAEs) and grade ≥3 TRAEs were evaluated to identify the efficacy and safety of dual immunotherapy regimens. The surface under the cumulative ranking curve (SUCRA) and P score were employed to rank the treatments.

Results

Eleven clinical trials involving six different regimens were included in this study. The combination of anti-programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) antibodies with anti-T-cell immunoglobulin and ITIM domain (TIGIT) antibodies emerged as the most promising regimen for improving OS and PFS, followed by anti-PD-1/PD-L1 + anti-cytotoxic T lymphocyte antigen 4 (CTLA-4) + chemotherapy treatment and anti-PD-1/PD-L1 + anti-CTLA-4 treatment. The forest plots demonstrated that these three regimens were all superior to chemotherapy. The above results were observed in both unselected treatment line and first-line settings. The least likely to be associated with TRAEs and grade ≥3 TRAEs were respectively anti-CTLA-4 treatment and anti-PD-1/PD-L1 + anti-TIGIT treatment, with anti-PD-1/PD-L1 + anti-CTLA-4 + chemotherapy treatment to be the worst.

Conclusions

This NMA validated the promising efficacy and safety of dual immunotherapy in advanced or metastatic NSCLC. Among them, anti-PD-1/PD-L1 + anti-TIGIT regimen emerges as a highly potential therapeutic approach. Ongoing research efforts should focus on improving treatment regimens, identifying biomarkers, and managing TRAEs to optimize the patient benefits of dual immunotherapy.

The enhanced antitumor activity of bispecific antibody targeting PD-1/PD-L1 signaling

The programmed cell death 1 (PD-1) signaling pathway, a key player in immune checkpoint regulation, has become a focal point in cancer immunotherapy. In the context of cancer, upregulated PD-L1 on tumor cells can result in T cell exhaustion and immune evasion, fostering tumor progression. The advent of PD-1/PD-L1 inhibitor has demonstrated clinical success by unleashing T cells from exhaustion. Nevertheless, challenges such as resistance and adverse effects have spurred the exploration of innovative strategies, with bispecific antibodies (BsAbs) emerging as a promising frontier. BsAbs offer a multifaceted approach to cancer immunotherapy by simultaneously targeting PD-L1 and other immune regulatory molecules. We focus on recent advancements in PD-1/PD-L1 therapy with a particular emphasis on the development and potential of BsAbs, especially in the context of solid tumors. Various BsAb products targeting PD-1 signaling are discussed, highlighting their unique mechanisms of action and therapeutic potential. Noteworthy examples include anti-TGFβ × PD-L1, anti-CD47 × PD-L1, anti-VEGF × PD-L1, anti-4-1BB × PD-L1, anti-LAG-3 × PD-L1, and anti-PD-1 × CTLA-4 BsAbs. Besides, we summarize ongoing clinical studies evaluating the efficacy and safety of these innovative BsAb agents. By unraveling the intricacies of the tumor microenvironment and harnessing the synergistic effects of anti-PD-1/PD-L1 BsAbs, there exists the potential to elevate the precision and efficacy of cancer immunotherapy, ultimately enabling the development of personalized treatment strategies tailored to individual patient profiles.

HOXC9 characterizes a suppressive tumor immune microenvironment and integration with multiple immune biomarkers predicts response to PD-1 blockade plus chemotherapy in lung adenocarcinoma

BACKGROUND

The quest for dependable biomarkers to predict responses to immune checkpoint inhibitors (ICIs) combined with chemotherapy in advanced non-small cell lung cancer remains unfulfilled. HOXC9, known for its role in oncogenesis and creating a suppressive tumor microenvironment (TME), shows promise in enhancing predictive precision when included as a TME biomarker. This study explores the predictive significance of HOXC9 for ICI plus chemotherapy efficacy in lung adenocarcinoma (LUAD).

METHODS

Following the bioinformatic findings, assays were performed to ascertain the effects of Hoxc9 on oncogenesis and response to programmed death 1 (PD-1) blockade. Furthermore, a cohort of LUAD patients were prospectively enrolled to receive anti-PD-1 plus chemotherapy. Based on the expression levels, baseline characteristics, and clinical outcomes, the predictive potential of HOXC9, PD-L1, CD4, CD8, CD68, and FOXP3 was integrally analyzed. HOXC9 not only mediated oncogenesis, but also corelated with suppressive TME. CMT167 and LLC cell lines unveiled the impacts of Hoxc9 on proliferation, invasion, and migration. Subsequently, tumor-bearing murine models were established to validate the inverse relationship between Hoxc9 expression and effective CD8+ T cells.

RESULTS

Inhibition of Hoxc9 significantly curtailed tumor growth (P<0.05), independent of PD-1 blockade. In patient studies, while individual markers fell short in prognosticating survival, a notable elevation in CD8-positive expression was observed in responders (P=0.042). Yet, the amalgamation of HOXC9 with other markers provided a more distinct differentiation between responders and non-responders. Notably, patients displaying PD-L1+/HOXC9- and CD8+/HOXC9- phenotypes exhibited significantly prolonged progression-free survival.

CONCLUSIONS

The expression of HOXC9 may serve as a biomarker to amplifying predictive efficacy for ICIs plus chemotherapy, which is also a viable oncogene and therapeutic target for immunotherapy in LUAD.

Enhancing anti-CD274 (PD-L1) targeting through combinatorial immunotherapy with bispecific antibodies and fusion proteins: from preclinical to phase II clinical trials

INTRODUCTION

Immune checkpoint inhibitors have achieved great success in the treatment of many different types of cancer. Programmed cell death protein ligand 1 (PD-L1, CD274) is a major immunosuppressive immune checkpoint and a target for several already approved monoclonal antibodies. Despite this, novel strategies are under development, as the overall response remains low.

AREAS COVERED

In this review, an overview of the current biomarkers for response to PD-L1 inhibitor treatment is given, followed by a discussion of potential novel biomarkers, including tumor mutational burden and circulating tumor DNA. Combinatorial immunotherapy is a potential novel strategy to increase the response to PD-L1 inhibitor treatment and currently, several interesting bispecific antibodies as well as bispecific fusion proteins are undergoing early clinical investigation. We focus on substances targeting PD-L1 and a secondary target, and a secondary immunomodulatory target like CTLA-4, TIGIT, or CD47.

EXPERT OPINION

Overall, the presented studies show anti-tumor activity of these combinatorial immunotherapeutic approaches. However, still relatively low response rates suggest a need for better biomarkers.

Reprogramming of regulatory T cells in inflammatory tumor microenvironment: can it become immunotherapy turning point?

Overcoming the immunosuppressive tumor microenvironment and identifying widely used immunosuppressants with minimal side effects are two major challenges currently hampering cancer immunotherapy. Regulatory T cells (Tregs) are present in almost all cancer tissues and play an important role in preserving autoimmune tolerance and tissue homeostasis. The tumor inflammatory microenvironment causes the reprogramming of Tregs, resulting in the conversion of Tregs to immunosuppressive phenotypes. This process ultimately facilitates tumor immune escape or tumor progression. However, current systemic Treg depletion therapies may lead to severe autoimmune toxicity. Therefore, it is crucial to understand the mechanism of Treg reprogramming and develop immunotherapies that selectively target Tregs within tumors. This article provides a comprehensive review of the potential mechanisms involved in Treg cell reprogramming and explores the application of Treg cell immunotherapy. The interference with reprogramming pathways has shown promise in reducing the number of tumor-associated Tregs or impairing their function during immunotherapy, thereby improving anti-tumor immune responses. Furthermore, a deeper understanding of the mechanisms that drive Treg cell reprogramming could reveal new molecular targets for future treatments.

Influence of treatment-related lymphopenia on the efficacy of immune checkpoint inhibitors in lung cancer: a meta-analysis

Background

Treatment-related lymphopenia (TRL) is common in patients with lung cancer, particularly in those with radiotherapy. However, the influence of TRL on the efficacy of immune checkpoint inhibitors (ICIs) for patients with lung cancer remains poorly understood. We performed a systematic review and meta-analysis to investigate the influence of TRL on survival of lung cancer patients on ICIs.

Methods

In order to accomplish the aim of the meta-analysis, a comprehensive search was conducted on databases including PubMed, Embase, Cochrane Library, and the Web of Science to identify observational studies with longitudinal follow-up. The Cochrane Q test was employed to evaluate heterogeneity among the included studies, while the I2 statistic was estimated. Random-effects models were utilized to merge the results, considering the potential impact of heterogeneity.

Results

Ten cohort studies with 1130 lung cancer patients who were treated with ICIs were included. Among them, 427 (37.8%) had TRL. Pooled results showed that compared to patients without TRL, patients with TRL were associated with poor progression-free survival (hazard ratio [HR]: 2.05, 95% confidence interval [CI]: 1.62 to 2.60, p < 0.001; I2 = 22%) and overall survival (HR: 2.69, 95% CI: 2.10 to 3.43, p < 0.001; I2 = 0%). Sensitivity analysis limited to patients with non-small cell lung cancer showed similar results (HR: 2.66 and 2.62, both p < 0.05). Moreover, subgroup analyses according to the diagnostic criteria of TRL, regression analysis model (univariate or multivariate), and indications of ICIs (for locally advanced or advanced lung cancer) showed consistent results (p for subgroup difference all > 0.05).

Conclusion

TRL was associated with poor survival of lung cancer patients who were treated with ICIs.

Manipulating TGF-β signaling to optimize immunotherapy for cervical cancer

Cervical cancer is a serious threat to women's health globally. Therefore, identifying key molecules associated with cervical cancer progression is essential for drug development, disease monitoring, and precision therapy. Recently, TGF-β (transforming growth factor-beta) has been identified as a promising target for cervical cancer treatment. For advanced cervical cancer, TGF-β participates in tumor development by improving metastasis, stemness, drug resistance, and immune evasion. Accumulating evidence demonstrates that TGF-β blockade effectively improves the therapeutic effects, especially immunotherapy. Currently, agents targeting TGF-β and immune checkpoints such as PD-L1 have been developed and tested in clinical studies. These bispecific antibodies might have the potential as therapeutic agents for cervical cancer treatment in the future.

MFSD2A potentiates gastric cancer response to anti-PD-1 immunotherapy by reprogramming the tumor microenvironment to activate T cell response

BACKGROUND

The efficacy of anti-programmed cell death protein 1 (PD-1) immunotherapy in various cancers, including gastric cancer (GC), needs to be potentiated by more effective targeting to enhance therapeutic efficacy or identifying accurate biomarkers to predict clinical responses. Here, we attempted to identify molecules predicting or/and promoting anti-PD-1 therapeutic response in advanced GC (AGC).

METHODS

The transcriptome of AGC tissues from patients with different clinical responses to anti-PD-1 immunotherapy and GC cells was analyzed by RNA sequencing. The protein and mRNA levels of the major facilitator superfamily domain containing 2A (MFSD2A) in GC cells were assessed via quantitative real-time polymerase chain reaction, Western blotting, and immunohistochemistry. Additionally, the regulation of anti-PD-1 response by MFSD2A was studied in tumor-bearing mice. Cytometry by Time-of-Flight, multiple immunohistochemistry, and flow cytometry assays were used to explore immunological responses. The effects of MFSD2A on lipid metabolism in mice cancer tissue and GC cells was detected by metabolomics.

RESULTS

Higher expression of MFSD2A in tumor tissues of AGC patients was associated with better response to anti-PD-1 immunotherapy. Moreover, MFSD2A expression was lower in GC tissues compared to adjacent normal tissues, and its expression was inversely correlated with GC stage. The overexpression of MFSD2A in GC cells enhanced the efficacy of anti-PD-1 immunotherapy in vivo by reprogramming the tumor microenvironment (TME), characterized by increased CD8+ T cell activation and reduced its exhaustion. MFSD2A inhibited transforming growth factor β1 (TGFβ1) release from GC cells by suppressing cyclooxygenase 2 (COX2)-prostaglandin synthesis, which consequently reprogrammed TME to promote anti-tumor T cell activation.

CONCLUSIONS

MFSD2A potentially serves as a predictive biomarker for anti-PD-1 immunotherapy response in AGC patients. MFSD2A may be a promising therapeutic target to potentiate the efficacy of anti-PD-1 immunotherapy by reprogramming the TME to promote T cells activation.

Drug resistance mechanism and reversal strategy in lung cancer immunotherapy

Among all malignant tumors, lung cancer has the highest mortality and morbidity rates. The non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) are the most common histological subtypes. Although there are a number of internationally recognized lung cancer therapy regimens, their therapeutic effects remain inadequate. The outlook for individuals with lung carcinoma has ameliorated partly thanks to the intensive study of the tumor microenvironment and immune checkpoint inhibitors. Numerous cancers have been effectively treated with immunotherapy, which has had positive therapeutic results. Global clinical trials have validated that PD-1/PD-L1 inhibitors are effective and safe for treating lung cancer either independently or in combination, and they are gradually being recommended as systemic treatment medications by numerous guidelines. However, the immunotherapy resistance restricts the immunotherapy efficacy due to the formation of tumor immunosuppressive microenvironment and tumor mutations, and immunotherapy is only effective for a small percentage of lung cancer patients. To summarize, while tumor immunotherapy is benefiting an increasing number of lung cancer patients, most of them still develop natural or acquired resistance during immunotherapy. Consequently, a crucial and urgent topic is understanding and tackling drug resistance triggered by immunotherapy in lung cancer treatment. This review will outline the presently recognized mechanisms of immunotherapy resistance and reversal strategies in lung cancer.

Dual anti-PD-(L)1/TGF-β inhibitors in cancer immunotherapy - Updated

Immune checkpoint inhibitor (ICI) therapy suffers from tumor resistance and relapse in majority of patients due to the suppressive tumor immune microenvironment (TIME). Advances in the field have brought about development of fusion proteins able to target two signaling simultaneously and to exert maximal anti-cancer immunity. Bispecific inhibitors of transforming growth factor (TGF)-β signaling and programmed death-1 (PD-1) or programmed death-ligand 1 (PD-L1) are developed to reduce the rate of relapse and to achieve durable anti-cancer therapy. TGF-β is well-known for its immunosuppressive activity, and it takes critical roles in promotion of all tumor hallmarks. Bispecific anti-PD-(L)1/TGF-β inhibitors reinvigorate effector activity of CD8+ T and natural killer (NK) cells, hamper regulatory T cell (Treg) expansion, and increase the density of anti-tumor type 1 macrophages (M1). Responses to the bispecific approach are higher compared with solo anti-PD-(L)1 or TGF-β targeted therapy, and are seemingly more pronounced in human papillomavirus (HPV)+ patients. High expression of PD-L1 or immune-excluded phenotype in a tumor can also be markers of better response to the bispecific strategy. Besides, anti-PD-(L)1/TGF-β inhibitor therapy can be used safely with other therapeutic modalities including vaccination, radiation and chemotherapy.

A pilot study of camrelizumab with docetaxel and cisplatin for the first line treatment in recurrent/metastatic oral squamous cell carcinoma

Pembrolizumab with cisplatin and 5-fluorouracil showed survival benefit but relatively high occurrence of treatment-related adverse events (TRAEs) for recurrent/metastatic oral squamous cell carcinoma (R/M OSCC). A more tolerable regime is needed. This trial enrolled 20 R/M OSCC patients with previously untreated and PD-L1 positive. Patients were administered camrelizumab with docetaxel and cisplatin every 3 weeks for six cycles, followed by camrelizumab monotherapy every 3 weeks until disease progression or intolerable toxicity. The primary endpoint was occurrence of grade ≥ 3 TRAEs, secondary endpoints included overall survival (OS), progression-free survival (PFS), and overall response rate (ORR). 45% patients experienced grade ≥ 3 TRAEs, which the most common were anemia (15%), stomatitis (15%), and neutropenia (10%). The most common potential immune-related adverse events were reactive cutaneous capillary endothelial proliferation (RCCEP; 60%), hypothyroidism (35%), and pneumonitis (15%). No treatment-related deaths occurred. The median OS, PFS, and ORR was 14.4 months, 5.35 months, and 40.0% respectively. The study also found RCCEP occurrence, lower FOXP3⁺ cells, and higher density of intratumor tertiary lymphoid structure were associated with improved efficacy. Our data suggest that camrelizumab with docetaxel/cisplatin as first-line therapy was well tolerable and had potentially favorite efficacy in PD-L1-positive patients with R/M OSCC.

Bispecific antibody targeting TGF-β and PD-L1 for synergistic cancer immunotherapy

The PD-1/PD-L1 signaling pathway plays a crucial role in cancer immune evasion, and the use of anti-PD-1/PD-L1 antibodies represents a significant milestone in cancer immunotherapy. However, the low response rate observed in unselected patients and the development of therapeutic resistance remain major obstacles to their clinical application. Accumulating studies showed that overexpressed TGF-β is another immunosuppressive factor apart from traditional immune checkpoints. Actually, the effects of PD-1 and TGF-β pathways are independent and interactive, which work together contributing to the immune evasion of cancer cell. It has been verified that blocking TGF-β and PD-L1 simultaneously could enhance the efficacy of PD-L1 monoclonal antibody and overcome its treatment resistance. Based on the bispecific antibody or fusion protein technology, multiple bispecific and bifunctional antibodies have been developed. In the preclinical and clinical studies, these updated antibodies exhibited potent anti-tumor activity, superior to anti-PD-1/PD-L1 monotherapies. In the review, we summarized the advances of bispecific antibodies targeting TGF-β and PD-L1 in cancer immunotherapy. We believe these next-generation immune checkpoint inhibitors would substantially alter the cancer treatment paradigm, especially in anti-PD-1/PD-L1-resistant patients.

Radiation-induced tumor immune microenvironments and potential targets for combination therapy

As one of the four major means of cancer treatment including surgery, radiotherapy (RT), chemotherapy, immunotherapy, RT can be applied to various cancers as both a radical cancer treatment and an adjuvant treatment before or after surgery. Although RT is an important modality for cancer treatment, the consequential changes caused by RT in the tumor microenvironment (TME) have not yet been fully elucidated. RT-induced damage to cancer cells leads to different outcomes, such as survival, senescence, or death. During RT, alterations in signaling pathways result in changes in the local immune microenvironment. However, some immune cells are immunosuppressive or transform into immunosuppressive phenotypes under specific conditions, leading to the development of radioresistance. Patients who are radioresistant respond poorly to RT and may experience cancer progression. Given that the emergence of radioresistance is inevitable, new radiosensitization treatments are urgently needed. In this review, we discuss the changes in irradiated cancer cells and immune cells in the TME under different RT regimens and describe existing and potential molecules that could be targeted to improve the therapeutic effects of RT. Overall, this review highlights the possibilities of synergistic therapy by building on existing research.

Mechanisms of CD8+ T cell exclusion and dysfunction in cancer resistance to anti-PD-(L)1

CD8⁺ T cells are the front-line defensive cells against cancer. Reduced infiltration and effector function of CD8⁺ T cells occurs in cancer and is contributed to defective immunity and immunotherapy resistance. Exclusion and exhaustion of CD8⁺ T cells are the two key factors associated with reduced durability of immune checkpoint inhibitor (ICI) therapy. Initially activated T cells upon exposure to chronic antigen stimulation or immunosuppressive tumor microenvironment (TME) acquire a hyporesponsive state that progressively lose their effector function. Thus, a key strategy in cancer immunotherapy is to look for factors contributed to defective CD8⁺ T cell infiltration and function. Targeting such factors can define a promising supplementary approach in patients receiving anti-programmed death-1 receptor (PD-1)/anti-programmed death-ligand 1 (PD-L1) therapy. Recently, bispecific antibodies are developed against PD-(L)1 and a dominant factor within TME, representing higher safety profile and exerting more desired outcomes. The focus of this review is to discuss about promoters of deficient infiltration and effector function of CD8⁺ T cells and their addressing in cancer ICI therapy.

Lipophagy-related gene RAB7A is involved in immune regulation and malignant progression in hepatocellular carcinoma

BACKGROUND

RAB7A (RAS-related in Brain 7A) is an important member of the RAS oncogene family. However, the correlation between RAB7A and the development and immune infiltration of hepatocellular carcinoma (HCC) has rarely been studied. Here, we studied the role of RAB7A in HCC through bioinformatics analysis, real-world cohort validation, and in vitro experimental exploration.

MATERIALS AND METHODS

The RAB7A expression level was analyzed through TCGA, HPA and TISIDB databases. TIMER and TISCH were used to analyze the correlation between RAB7A and tumor immune microenvironment. The expression of RAB7A was detected through real-time PCR and western blotting. The cell proliferation was detected by EdU and CCK8. Wound-healing and transwell assays were used to test the invasion and migration ability. Cell cycle distribution and reactive oxygen species (ROS) content were analyzed by flow cytometry. Identification of epithelial-mesenchymal transition (EMT) was performed by immunofluorescence double staining. Immunohistochemistry (IHC) was used to evaluate the correlation between RAB7A and immune checkpoints.

RESULTS

RAB7A is upregulated in most of the tumor types, and the upregulation of RAB7A is associated with a poorer prognosis in many cancers. The results showed that RAB7A was significantly positively correlated with the infiltration of macrophages and cancer-associated fibroblasts (CAFs), but negatively correlated with M2-type macrophages in most tumors. The single-cell atlas also revealed the distribution and proportion of RAB7A in immune cells of HCC. The in vitro experiments suggested that RAB7A was increased in HCC tissue and cell lines. The knockdown of RAB7A inhibited the activation of the PIK3CA-AKT pathway and suppressed the expression of CDK4, CDK6 and CCNA2. Knockdown of RAB7A induced G0/G1 arrest and ROS accumulation in HCC. In addition, overexpression of RAB7A enhanced migration and invasion by inducing EMT. The real-world cohort showed that the expression level of RAB7A was positively correlated with the expression levels of TGFBR1 and PD-L1.

CONCLUSIONS

RAB7A may serve as a potential tumor prognostic and immune infiltration-related biomarker, predicting immunotherapy efficacy in certain cancer types, especially in HCC. Besides, RAB7A was a multi-pathway target involved in the malignant progression of HCC.

A signature-based classification of lung adenocarcinoma that stratifies tumor immunity

Background

Immune-related subgroup classification in immune checkpoint blockade (ICB) therapy is largely inconclusive in lung adenocarcinoma (LUAD).

Materials and methods

First, the single-sample Gene Set Enrichment Analysis (ssGSEA) and K-means algorithms were used to identify immune-based subtypes for the LUAD cohort based on the immunogenomic profiling of 29 immune signatures from The Cancer Genome Atlas (TCGA) database (n = 504). Second, we examined the prognostic and predictive value of immune-based subtypes using bioinformatics analysis. Survival analysis and additional COX proportional hazards regression analysis were conducted for LUAD. Then, the immune score, tumor-infiltrating immune cells (TIICs), and immune checkpoint expression of the three subtypes were analyzed. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) of the differentially expressed genes (DEGs) between three immune-based subtypes were subsequently analyzed for functional enrichment pathways.

Result

A total of three immune-based subtypes with distinct immune signatures have been identified for LUAD and designated as cluster 1 (C1), cluster 2 (C2), and cluster 3 (C3). Patients in C3 had higher stromal, immune, and ESTIMATE scores, whereas those in C1 had the opposite. Patients in C1 had an enrichment of macrophages M0 and activation of dendritic cells, whereas tumors in C3 had an enrichment of CD8⁺ T cells, activation of CD4⁺ memory T cells, and macrophages M1. C3 had a higher immune cell infiltration and a better survival prognosis than other subtypes. Furthermore, patients in C3 had higher expression levels of immune checkpoint proteins such as PD-L1, PD1, CTLA4, LAG3, IDO1, and HAVCR2. No significant differences were found in cluster TMB scores. We also found that immune-related pathways were enriched in C3.

Conclusion

LUAD subtypes based on immune signatures may aid in the development of novel treatment strategies for LUAD.

Frizzled-7-targeting antibody (SHH002-hu1) potently suppresses non-small-cell lung cancer via Wnt/β-catenin signaling

Non-small-cell lung cancer (NSCLC) is one of the deadliest cancers worldwide, and metastasis is considered one of the leading causes of treatment failure in NSCLC. Wnt/β-catenin signaling is crucially involved in epithelial-mesenchymal transition (EMT), a crucial factor in promoting metastasis, and also contributes to resistance developed by NSCLC to targeted agents. Frizzled-7 (Fzd7), a critical receptor of Wnt/β-catenin signaling, is aberrantly expressed in NSCLC and has been confirmed to be positively correlated with poor clinical outcomes. SHH002-hu1, a humanized antibody targeting Fzd7, was previously successfully generated by our group. Here, we studied the anti-tumor effects of SHH002-hu1 against NSCLC and revealed the underlying mechanism. First, immunofluorescence (IF) and near-infrared (NIR) imaging assays showed that SHH002-hu1 specifically binds Fzd7⁺ NSCLC cells and targets NSCLC tissues. Wound healing and transwell invasion assays indicated that SHH002-hu1 significantly inhibits the migration and invasion of NSCLC cells. Subsequently, TOP-FLASH/FOP-FLASH luciferase reporter, IF, and western blot assays validated that SHH002-hu1 effectively suppresses the activation of Wnt/β-catenin signaling, and further attenuates the EMT of NSCLC cells. Finally, the subcutaneous xenotransplanted tumor model of A549/H1975, as well as the popliteal lymph node (LN) metastasis model, was established, and SHH002-hu1 was demonstrated to inhibit the growth of NSCLC xenografts and suppress LN metastasis of NSCLC. Above all, SHH002-hu1 with selectivity toward Fzd7⁺ NSCLC and the potential of inhibiting invasion and metastasis of NSCLC via disrupting Wnt/β-catenin signaling, is indicated as a good candidate for the targeted therapy of NSCLC.

Transforming growth factor-β signaling: from tumor microenvironment to anticancer therapy

Transforming growth factor-β (TGF-β) signaling is an important pathway for promoting the pathogenesis of inflammatory diseases, including cancer. The roles of TGF-β signaling are heterogeneous and versatile in cancer development and progression, both anticancer and protumoral actions are reported. Interestingly, increasing evidence suggests that TGF-β enhances disease progression and drug resistance via immune-modulatory actions in the tumor microenvironment (TME) of solid tumors. A better understanding of its regulatory mechanisms in the TME at the molecular level can facilitate the development of precision medicine to block the protumoral actions of TGF-β in the TME. Here, the latest information about the regulatory mechanisms and translational research of TGF-β signaling in the TME for therapeutic development had been summarized.

TGF-beta signal transduction: biology, function and therapy for diseases

The transforming growth factor beta (TGF-β) is a crucial cytokine that get increasing concern in recent years to treat human diseases. This signal controls multiple cellular responses during embryonic development and tissue homeostasis through canonical and/or noncanonical signaling pathways. Dysregulated TGF-β signal plays an essential role in contributing to fibrosis via promoting the extracellular matrix deposition, and tumor progression via inducing the epithelial-to-mesenchymal transition, immunosuppression, and neovascularization at the advanced stage of cancer. Besides, the dysregulation of TGF-beta signal also involves in other human diseases including anemia, inflammatory disease, wound healing and cardiovascular disease et al. Therefore, this signal is proposed to be a promising therapeutic target in these diseases. Recently, multiple strategies targeting TGF-β signals including neutralizing antibodies, ligand traps, small-molecule receptor kinase inhibitors targeting ligand-receptor signaling pathways, antisense oligonucleotides to disrupt the production of TGF-β at the transcriptional level, and vaccine are under evaluation of safety and efficacy for the forementioned diseases in clinical trials. Here, in this review, we firstly summarized the biology and function of TGF-β in physiological and pathological conditions, elaborated TGF-β associated signal transduction. And then, we analyzed the current advances in preclinical studies and clinical strategies targeting TGF-β signal transduction to treat diseases.

TGF-β: A novel predictor and target for anti-PD-1/PD-L1 therapy

Transforming growth factor-β (TGF-β) signaling regulates multiple physiological processes, such as cell proliferation, differentiation, immune homeostasis, and wound healing. Besides, TGF-β plays a vital role in diseases, including cancer. Accumulating evidence indicates that TGF-β controls the composition and behavior of immune components in the tumor microenvironment (TME). Advanced cancers leverage TGF-β to reshape the TME and escape immune surveillance. TGF-β-mediated immune evasion is an unfavorable factor for cancer immunotherapy, especially immune checkpoint inhibitors (ICI). Numerous preclinical and clinical studies have demonstrated that hyperactive TGF-β signaling is closely associated with ICI resistance. It has been validated that TGF-β blockade synergizes with ICI and overcomes treatment resistance. TGF-β-targeted therapies, including trap and bispecific antibodies, have shown immense potential for cancer immunotherapy. In this review, we summarized the predictive value of TGF-β signaling and the prospects of TGF-β-targeted therapies for cancer immunotherapy.

Bifunctional Blockade: A Novel Immunotherapy Approach for Cervical Cancer

SHR-1701, a bispecific fusion protein directed against PD-L1 and TGFβ, demonstrates promising clinical activity in advanced/recurrent cervical cancer. A recent study serves as a proof of principle that the TGFβ pathway may be successfully targeted, and that bispecific antibodies offer a novel therapeutic approach to do so. See related article by Feng et al., p. 5297.

Anti-TGF-β/PD-L1 bispecific antibody promotes T cell infiltration and exhibits enhanced antitumor activity in triple-negative breast cancer

BACKGROUND

Agents blocking programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) have been approved for triple-negative breast cancer (TNBC). However, the response rate of anti-PD-1/PD-L1 is still unsatisfactory, partly due to immunosuppressive factors such as transforming growth factor-beta (TGF-β). In our previous pilot study, the bispecific antibody targeting TGF-β and murine PD-L1 (termed YM101) showed potent antitumor effect. In this work, we constructed a bispecific antibody targeting TGF-β and human PD-L1 (termed BiTP) and explored the antitumor effect of BiTP in TNBC.

METHODS

BiTP was developed using Check-BODY^TM bispecific platform. The binding affinity of BiTP was measured by surface plasmon resonance, ELISA, and flow cytometry. The bioactivity was assessed by Smad and NFAT luciferase reporter assays, immunofluorescence, western blotting, and superantigen stimulation assays. The antitumor activity of BiTP was explored in humanized epithelial-mesenchymal transition-6-hPDL1 and 4T1-hPDL1 murine TNBC models. Immunohistochemical staining, flow cytometry, and bulk RNA-seq were used to investigate the effect of BiTP on immune cell infiltration.

RESULTS

BiTP exhibited high binding affinity to dual targets. In vitro experiments verified that BiTP effectively counteracted TGF-β-Smad and PD-L1-PD-1-NFAT signaling. In vivo animal experiments demonstrated that BiTP had superior antitumor activity relative to anti-PD-L1 and anti-TGF-β monotherapy. Mechanistically, BiTP decreased collagen deposition, enhanced CD8⁺ T cell penetration, and increased tumor-infiltrating lymphocytes. This improved tumor microenvironment contributed to the potent antitumor activity of BiTP.

CONCLUSION

BiTP retains parent antibodies' binding affinity and bioactivity, with superior antitumor activity to parent antibodies in TNBC. Our data suggest that BiTP might be a promising agent for TNBC treatment.

Overcoming the therapeutic resistance of hepatomas by targeting the tumor microenvironment

Hepatocellular carcinoma (HCC) accounts for the majority of primary liver cancers and is the third leading cause of cancer-related mortality worldwide. Multifactorial drug resistance is regarded as the major cause of treatment failure in HCC. Accumulating evidence shows that the constituents of the tumor microenvironment (TME), including cancer-associated fibroblasts, tumor vasculature, immune cells, physical factors, cytokines, and exosomes may explain the therapeutic resistance mechanisms in HCC. In recent years, anti-angiogenic drugs and immune checkpoint inhibitors have shown satisfactory results in HCC patients. However, due to enhanced communication between the tumor and TME, the effect of heterogeneity of the microenvironment on therapeutic resistance is particularly complicated, which suggests a more challenging research direction. In addition, it has been reported that the three-dimensional (3D) organoid model derived from patient biopsies is more intuitive to fully understand the role of the TME in acquired resistance. Therefore, in this review, we have focused not only on the mechanisms and targets of therapeutic resistance related to the contents of the TME in HCC but also provide a comprehensive description of 3D models and how they contribute to the exploration of HCC therapies.

Next-generation immunotherapy for solid tumors: combination immunotherapy with crosstalk blockade of TGFβ and PD-1/PD-L1

INTRODUCTION

In solid tumor immunotherapy, less than 20% of patients respond to anti-programmed cell death 1 (PD-1)/programmed cell death 1 ligand 1 (PD-L1) agents. The role of transforming growth factor β (TGFβ) in diverse immunity is well-established; however, systemic blockade of TGFβ is associated with toxicity. Accumulating evidence suggests the role of crosstalk between TGFβ and PD-1/PD-L1 pathways.

AREAS COVERED

We focus on TGFβ and PD-1/PD-L1 signaling pathway crosstalk and the determinant role of TGFβ in the resistance of immune checkpoint blockade. We provide the rationale for combination anti-TGFβ and anti-PD-1/PD-L1 therapies for solid tumors and discuss the current status of dual blockade therapy in preclinical and clinical studies.

EXPERT OPINION

The heterogeneity of tumor microenvironment across solid tumors complicates patient selection, treatment regimens, and response and toxicity assessment for investigation of dual blockade agents. However, clinical knowledge from single-agent studies provides infrastructure to translate dual blockade therapies. Dual TGFβ and PD-1/PD-L1 blockade results in enhanced T-cell infiltration into tumors, a primary requisite for successful immunotherapy. A bifunctional fusion protein specifically targets TGFβ in the tumor microenvironment, avoiding systemic toxicity, and prevents interaction of PD-1+ cytotoxic cells with PD-L1+ tumor cells.

Bidirectional regulation between tumor cell-intrinsic PD-L1 and TGF-β1 in epithelial-to-mesenchymal transition in melanoma

BACKGROUND

Transforming growth factor-β1 (TGF-β1) is the predominant form of TGF-β and induces epithelial-to-mesenchymal transition (EMT) in melanoma. Tumor cell-intrinsic programmed death ligand-1 (PD-L1) plays a crucial role in maintenance of the EMT in melanoma. However, the relationship among tumor cell-intrinsic PD-L1, TGF-β1 and EMT is very complicated.

METHODS

We investigated the bidirectional regulation between cell-intrinsic PD-L1 and TGF-β1 in melanoma, and explored the role of PD-L1 in TGF-β1-induced EMT and tumor progression.

RESULTS

We found that TGF-β1 upregulated PD-L1 expression in B16-F0 and B16-F10 melanoma cells. Interestingly, PD-L1 also enhanced the intracellular TGF-β1 mRNA levels and induced the secretion of TGF-β1. Immunohistochemical staining revealed that PD-L1 protein expression was co-localized with α-smooth muscle actin (SMA) protein expression in melanoma, suggesting that PD-L1 was associated with EMT. By using shRNA lentivirus to knockdown PD-L1 (PD-L1-shRNA) in melanoma cell lines, we showed that TGF-β1-induced EMT was significantly inhibited in PD-L1-shRNA melanoma cells, which was characterized by the lower fibronectin (FN1) mRNA and higher E-cadherin (CDH1) mRNA levels (both are EMT markers) than that in control. TGF-β1-induced melanoma cell proliferation and migration were also markedly inhibited in PD-L1-shRNA cells. Consistent with the observation in vitro, PD-L1 knockdown inhibited tumor growth and repressed TGF-β1-induced EMT characterized by reduction of FN1 and increase of CDH1 in mouse model.

CONCLUSIONS

The present study demonstrated a bidirectional regulation between cell-intrinsic PD-L1 and TGF-β1 in melanoma, which may help in designing promising combinations which include targeting TGF-β1 signaling along with PD-L1.

Immune checkpoints related-LncRNAs can identify different subtypes of lung cancer and predict immunotherapy and prognosis

BACKGROUND

Non-small cell lung cancer is the most common subtype of lung cancer in the world. However, the survival rate of non-small cell lung cancer patients remains low currently. Immune checkpoint and long non-coding RNAs are emerging as critical roles in prognostic significance and the immunotherapeutic response of non-small cell lung cancer. It is critical to discern LncRNAs related with immune checkpoints in patients with Non-small cell lung cancer.

METHODS

In this study, immune checkpoint-linked LncRNAs were determined and achieved by the co-expression analysis. Immune checkpoint-linked LncRNAs with noteworthy prognostic value (P < 0.05) gained were next utilized to separate into two cluster by non-negative matrix factorization (NMF). Univariate and a least absolute shrinkage and selection operator were applied to construct an immune checkpoint-linked LncRNAs model. Kaplan-Meier analysis, Gene Set Enrichment Analysis, and the nomogram were utilized to investigate the LncRNAs model. Lastly, the capability immunotherapy and chemotherapy prediction value of this risk model were also estimated.

RESULTS

The model consisting of ten immune checkpoint-related LncRNAs was acknowledged to be a self-determining predictor of prognosis. Through regrouping the NSCLC patients by this model, difference between them more efficiently on immunotherapeutic response, tumor microenvironment and chemotherapy response could be discovered. This risk model related to the immune checkpoint-based LncRNAs may have an excellent clinical prediction for prognosis and the immunotherapeutic response in patients with NSCLC.

CONCLUSIONS

We performed an integrative analysis of LncRNAs linked with immune checkpoints and emphasized the significance of NSCLC subtypes classification, immune checkpoints related LncRNAs in estimating the tumor microenvironment score, immune cell infiltration of the tumor, immunotherapy, and chemotherapy response.

Anti-PD-L1/TGF-βR fusion protein (SHR-1701) overcomes disrupted lymphocyte recovery-induced resistance to PD-1/PD-L1 inhibitors in lung cancer

Background

Second‐generation programmed cell death‐protein 1/programmed death‐ligand 1 (PD‐1/PD‐L1) inhibitors, such as bintrafusp alfa (M7824), SHR‐1701, and YM101, have been developed to simultaneously block PD‐1/PD‐L1 and transforming growth factor‐beta/transforming growth factor‐beta receptor (TGF‐β/TGF‐βR). Consequently, it is necessary to identify predictive factors of lung cancer patients who are not only resistant to PD‐1/PD‐L1 inhibitors but also sensitive to bifunctional drugs. The purpose of this study was to search for such predictors.

Methods

Multivariable Cox regression was used to study the association between the clinical outcome of treatment with PD‐1/PD‐L1 inhibitors and lymphocyte recovery after lymphopenia in lung cancer patients. Murine CMT167 lung cancer cells were engineered to express the firefly luciferase gene and implanted orthotopically in the lung of syngeneic mice. Bioluminescence imaging, flow cytometry, and immunohistochemistry were employed to determine response to immunotherapy and function of tumor‐infiltrating immune cells.

Results

For lung cancer patients treated with anti‐PD‐1/PD‐L1 antibodies, poor lymphocyte recovery was associated with a shorter progression‐free survival (PFS; P < 0.001), an accumulation of regulatory T cells (Tregs), and an elimination of CD8⁺ T cells in the peripheral blood. Levels of CD8⁺ T cells and Treg cells were also imbalanced in the tumors and peripheral immune organs of mice with poor lymphocyte recovery after chemotherapy. Moreover, these mice failed to respond to anti‐PD‐1 antibodies but remained sensitive to the anti‐PD‐L1/TGF‐βR fusion protein (SHR‐1701). Consistently, SHR‐1701 but not anti‐PD‐1 antibodies, markedly enhanced IFN‐γ production and Ki‐67 expression in peripheral CD8⁺ T cells from patients with impaired lymphocyte recovery.

Conclusions

Lung cancer patients with poor lymphocyte recovery and suffering from persistent lymphopenia after previous chemotherapy are resistant to anti‐PD‐1/PD‐L1 antibodies but might be sensitive to second‐generation agents such as SHR‐1701.