High expression of B7-H3 on stromal cells defines tumor and stromal compartments in epithelial ovarian cancer and is associated with limited immune activation

The miR-29 family facilitates the activation of NK-cell immune responses by targeting the B7-H3 immune checkpoint in neuroblastoma

Neuroblastoma (NB) is a highly aggressive pediatric cancer that originates from immature nerve cells, presenting significant treatment challenges due to therapy resistance. Despite intensive treatment, approximately 50% of high-risk NB cases exhibit therapy resistance or experience relapse, resulting in poor outcomes often associated with tumor immune evasion. B7-H3 is an immune checkpoint protein known to inhibit immune responses. MicroRNAs (miRNAs) are small non-coding RNAs involved in post-transcriptional gene regulation. Our study aims to explore the impact of miRNAs on B7-H3 regulation, the anti-tumor immune response, and tumorigenicity in NB. Analysis of NB patients and patient-derived xenograft tumors revealed a correlation between higher B7-H3 expression and poorer patient survival. Notably, deceased patients exhibited a depletion of miR-29 family members (miR-29a, miR-29b, and miR-29c), which displayed an inverse association with B7-H3 expression in NB patients. Overexpression and knockdown experiments demonstrated that these miRNAs degrade B7-H3 mRNA, resulting in enhanced NK cell activation and cytotoxicity. In vivo, experiments provided further evidence that miR-29 family members reduce tumorigenicity, macrophage infiltration, and microvessel density, promote infiltration and activation of NK cells, and induce tumor cell apoptosis. These findings offer a rationale for developing more effective combination treatments that leverage miRNAs to target B7-H3 in NB patients.

Immune pathway through endometriosis to ovarian cancer

Endometriosis is an estrogen-dependent inflammatory disease, defined by the presence of functional endometrial tissue outside of the uterine cavity. This disease is one of the main gynecological diseases, affecting around 10%-15% women and girls of reproductive age, being a common gynecologic disorder. Although endometriosis is a benign disease, it shares several characteristics with invasive cancer. Studies support that it has been linked with an increased chance of developing endometrial ovarian cancer, representing an earlier stage of neoplastic processes. This is particularly true for women with clear cell carcinoma, low-grade serous carcinoma and endometrioid. However, the carcinogenic pathways between both pathologies remain poorly understood. Current studies suggest a connection between endometriosis and endometriosis-associated ovarian cancers (EAOCs) via pathways associated with oxidative stress, inflammation, and hyperestrogenism. This article aims to review current data on the molecular events linked to the development of EAOCs from endometriosis, specifically focusing on the complex relationship between the immune response to endometriosis and cancer, including the molecular mechanisms and their ramifications. Examining recent developments in immunotherapy and their potential to boost the effectiveness of future treatments.

Induction of NK cell reactivity against acute myeloid leukemia by Fc-optimized CD276 (B7-H3) antibody

Acute myeloid leukemia (AML) remains a therapeutic challenge despite recent therapeutic advances. Although monoclonal antibodies (mAbs) engaging natural killer (NK) cells via antibody-dependent cellular cytotoxicity (ADCC) hold promise in cancer therapy, almost none have received clinical approval for AML, so far. Recently, CD276 (B7-H3) has emerged as a promising target for AML immunotherapy, due to its high expression on leukemic blasts of AML patients. Here, we present the preclinical development of the Fc-optimized CD276 mAb 8H8_SDIE with enhanced CD16 affinity. We demonstrate that 8H8_SDIE specifically binds to CD276 on AML cell lines and primary AML cells and induces pronounced NK cell activation and degranulation as measured by CD69, CD25, and CD107a. Secretion of IFNγ, TNF, granzyme B, granulysin, and perforin, which mediate NK cell effector functions, was induced by 8H8_SDIE. A pronounced target cell-restricted lysis of AML cell lines and primary AML cells was observed in cytotoxicity assays using 8H8_SDIE. Finally, xenograft models with 8H8_SDIE did not cause off-target immune activation and effectively inhibited leukemia growth in vivo. We here present a novel attractive immunotherapeutic compound that potently induces anti-leukemic NK cell reactivity in vitro and in vivo as treatment option for AML.

Antibody-Drug Conjugates: Advancing from Magic Bullet to Biological Missile

Precision drug development is focusing on targeting tumor cell surface proteins for therapeutic delivery, maximizing biomarker identified on-target damage to the tumor while minimizing toxicity. A recent article demonstrated high expression of B7-H4 antigen on resistant ovarian cancer cells and described preclinical activity of B7-H4-directed antibody-drug conjugate. See related article by Gitto et al., p. 1567.

Adoptive cell therapy for solid tumors beyond CAR-T: Current challenges and emerging therapeutic advances

Adoptive cellular immunotherapy using immune cells expressing chimeric antigen receptors (CARs) is a highly specific anti-tumor immunotherapy that has shown promise in the treatment of hematological malignancies. However, there has been a slow progress toward the treatment of solid tumors owing to the complex tumor microenvironment that affects the localization and killing ability of the CAR cells. Solid tumors with a strong immunosuppressive microenvironment and complex vascular system are unaffected by CAR cell infiltration and attack. To improve their efficacy toward solid tumors, CAR cells have been modified and upgraded by "decorating" and "pruning". This review focuses on the structure and function of CARs, the immune cells that can be engineered by CARs and the transformation strategies to overcome solid tumors, with a view to broadening ideas for the better application of CAR cell therapy for the treatment of solid tumors.

High B7-H3 expression with low PD-L1 expression identifies armored-cold tumors in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is generally regarded as the most aggressive subtype among breast cancers, but exhibits higher chemotherapeutic and immunotherapeutic responses due to its unique immunogenicity. Thus, appropriate discrimination of subtypes is critical for guiding therapeutic options in clinical practice. In this research, using multiple in-house and public cohorts, we investigated the expression features and immuno-correlations of B7-H3 in breast cancer and checked the anti-tumor effect of the B7-H3 monoclonal antibody in a mouse model. We also developed a novel classifier combining B7-H3 and PD-L1 expression in TNBC. B7-H3 was revealed to be related to immuno-cold features and accumulated collagen in TNBC. In addition, targeting B7-H3 using the monoclonal antibody significantly suppressed mouse TNBC growth, reversed the armored-cold phenotype, and also boosted anti-PD-1 immunotherapy. In addition, patients with B7-H3 high and PD-L1 low expression showed the lowest anti-tumor immune infiltration, the highest collagen level, and the lowest therapeutic responses to multiple therapies, which mostly belong to armored-cold tumors. Overall, this research provides a novel subtyping strategy based on the combination of B7-H3/PD-L1 expression, which leads to a novel approach for the management of TNBC.

The immune regulatory function of B7-H3 in malignancy: spotlight on the IFN-STAT1 axis and regulation of tumor-associated macrophages

B7-H3 is a member of the B7 superfamily and a putative inhibitory immune checkpoint molecule. Several early-phase clinical trials have reported promising anti-tumor activity and safety of anti-cancer drugs targeting B7-H3, suggesting that it may be a promising target for a potential next-generation immune checkpoint inhibitor. Despite ongoing clinical studies, most B7-H3-targeted drugs being currently investigated rely on direct cytotoxicity as their mechanisms of action rather than modulating its function as an immune checkpoint, at least in part due to its incompletely understood immune regulatory function. Recent studies have begun to elucidate the role of B7-H3 in regulating the tumor microenvironment (TME). Emerging evidence suggests that B7-H3 may regulate the interferon-STAT1 axis in the TME and promote immune suppression. Similarly, increasing evidence shows B7-H3 may be implicated in promoting M1 to M2 polarization of tumor-associated macrophages (TAMs). There is also accumulating evidence suggesting that B7-H3 may play a role in the heterotypic fusion of cancer stem cells and macrophages, thereby promoting tumor invasion and metastasis. Here, we review the recent advances in the understanding of B7-H3 cancer immunobiology with a focus on highlighting its potential role in the interferon priming of TAMs and the heterotypic fusion of TAMs with cancer stem cells and suggest future direction in elucidating its immune checkpoint function.

New Emerging Targets in Cancer Immunotherapy: The Role of B7-H3

Immune checkpoints (ICs) are molecules implicated in the fine-tuning of immune response via co-inhibitory or co-stimulatory signals, and serve to secure minimized host damage. Targeting ICs with various therapeutic modalities, including checkpoint inhibitors/monoclonal antibodies (mAbs), antibody-drug conjugates (ADCs), and CAR-T cells has produced remarkable results, especially in immunogenic tumors, setting a paradigm shift in cancer therapeutics through the incorporation of these IC-targeted treatments. However, the large proportion of subjects who experience primary or secondary resistance to available IC-targeted options necessitates further advancements that render immunotherapy beneficial for a larger patient pool with longer duration of response. B7-H3 (B7 Homolog 3 Protein, CD276) is a member of the B7 family of IC proteins that exerts pleiotropic immunomodulatory effects both in physiologic and pathologic contexts. Mounting evidence has demonstrated an aberrant expression of B7-H3 in various solid malignancies, including tumors less sensitive to current immunotherapeutic options, and has associated its expression with advanced disease, worse patient survival and impaired response to IC-based regimens. Anti-B7-H3 agents, including novel mAbs, bispecific antibodies, ADCs, CAR-T cells, and radioimmunotherapy agents, have exhibited encouraging antitumor activity in preclinical models and have recently entered clinical testing for several cancer types. In the present review, we concisely present the functional implications of B7-H3 and discuss the latest evidence regarding its prognostic significance and therapeutic potential in solid malignancies, with emphasis on anti-B7-H3 modalities that are currently evaluated in clinical trial settings. Better understanding of B7-H3 intricate interactions in the tumor microenvironment will expand the oncological utility of anti-B7-H3 agents and further shape their role in cancer therapeutics.

The anti-B7-H3 blocking antibody MJ18 does not recognize B7-H3 in murine tumor models

The immune checkpoint molecule B7-H3 is regarded as one of the most promising therapeutic targets for the treatment of human cancers. B7-H3 is highly expressed in many cancers and its expression has been associated to impaired antitumor immunity and poor patient prognosis. In immunocompetent mouse tumor models, genetic deletion of B7-H3 in tumor cells enhances antitumor immune response leading to tumor shrinkage. The underlying mechanisms of B7-H3 inhibitory function remain largely uncharacterized and the identity of potential cognate(s) receptor(s) of B7-H3 is still to be defined. To better understand B7-H3 function in vivo, several studies have employed MJ18, a monoclonal antibody reported to bind murine B7-H3 and blocks its immune-inhibitory function. In this brief research report, we show that 1) MJ18 does not bind B7-H3, 2) MJ18 binds the Fc receptor FcγRIIB on surface of murine splenocytes, and 3) MJ18 does not induce tumor regression in a mouse model responsive to B7-H3 knockout. Given the high profile of B7-H3 as therapeutic target for human cancers, our work emphasizes that murine B7-H3 studies using the MJ18 antibody should be interpreted with caution. Finally, we hope that our study will motivate the scientific community to establish much-needed validated research tools to study B7-H3 biology in mouse models.

Bispecific antibody targeting both B7-H3 and PD-L1 exhibits superior antitumor activities

Clinical application of PD-1 and PD-L1 monoclonal antibodies (mAbs) is hindered by their relatively low response rates and the occurrence of drug resistance. Co-expression of B7-H3 with PD-L1 has been found in various solid tumors, and combination therapies that target both PD-1/PD-L1 and B7-H3 pathways may provide  additional therapeutic benefits. Up to today, however, no bispecific antibodies targeting both PD-1 and B7-H3 have reached the clinical development stage. In this study, we generated a stable B7-H3×PD-L1 bispecific antibody (BsAb) in IgG1-VHH format by coupling a humanized IgG1 mAb against PD-L1 with a humanized camelus variable domain of the heavy-chain of heavy-chain antibody (VHH) against human B7-H3. The BsAb exhibited favorable thermostability, efficient T cell activation, IFN-γ production, and antibody-dependent cell-mediated cytotoxicity (ADCC). In a PBMC humanized A375 xenogeneic tumor model, treatment with BsAb (10 mg/kg, i.p., twice a week for 6 weeks) showed enhanced antitumor activities compared to monotherapies and, to some degree, combination therapies. Our results suggest that targeting both PD-1 and B7-H3 with BsAbs increases their specificities to B7-H3 and PD-L1 double-positive tumors and induces a synergetic effect. We conclude that B7-H3×PD-L1 BsAb is favored over mAbs and possibly combination therapies in treating B7-H3 and PD-L1 double-positive tumors.

Preconditioning of radiotherapy enhances efficacy of B7-H3-CAR-T in treating solid tumor models

AIMS

Limited efficacy of chimeric antigen receptor T (CAR-T) cells in treating solid tumors is largely due to the antigen heterogeneity and immunosuppressive tumor microenvironment (TME). B7-H3 is over-expressed in most kind of solid tumors, making it a promising target for cancer treatment. This study aims to explore the effect of B7-H3-CAR-T therapy combined with radiotherapy in treating solid tumor models.

METHODS

Irradiated tumor cell lines were prepared and tested. A humanized B7-H3-CAR-T was constructed, and it was evaluated that B7-H3-CAR-T cytotoxicity against solid tumor models with preconditioning of radiotherapy in vitro and vivo.

RESULTS

Irradiation was found to increase expression level of B7-H3 in pancreatic cancer (PANC-1), colorectal cancer (HCT-15, SW620), acute myelocytic leukemia (AML-5), epidermoid carcinoma (KB) and glioma (U87-MG) human cell lines significantly. 6Gy irradiation was also found to up-regulate tumor-infiltration molecule like intracellular adhesion molecule-1 ICAM-1 or FAS in HCT-15 cells, supporting a possible synergistic enhancement effect of radiotherapy. In vitro and in vivo experiments demonstrated that irradiation indeed significantly enhanced the ability of B7-H3-CAR-T to infiltrate and kill tumors. Interestingly in dual-tumor mouse model study, not only tumor cells on irradiation side were eradicated completely, irradiation also enhanced CAR-T tumor-killing ability on non-irradiated side, confirming the abscopal effect of irradiation existed with CAR-T therapy.

CONCLUSIONS

Our results suggest that B7-H3-CAR-T therapy combined with radiotherapy may be a promising modality in treating solid tumors.

Therapeutic Targets of Monoclonal Antibodies Used in the Treatment of Cancer: Current and Emerging

Cancer is one of the leading global causes of death and disease, and treatment options are constantly evolving. In this sense, the use of monoclonal antibodies (mAbs) in immunotherapy has been considered a fundamental aspect of modern cancer therapy. In order to avoid collateral damage, it is indispensable to identify specific molecular targets or biomarkers of therapy and/or diagnosis (theragnostic) when designing an appropriate immunotherapeutic regimen for any type of cancer. Furthermore, it is important to understand the currently employed mAbs in immunotherapy and their mechanisms of action in combating cancer. To achieve this, a comprehensive understanding of the biology of cancer cell antigens, domains, and functions is necessary, including both those presently utilized and those emerging as potential targets for the design of new mAbs in cancer treatment. This review aims to provide a description of the therapeutic targets utilized in cancer immunotherapy over the past 5 years, as well as emerging targets that hold promise as potential therapeutic options in the application of mAbs for immunotherapy. Additionally, the review explores the mechanisms of actin of the currently employed mAbs in immunotherapy.

B7-H3 immunoregulatory roles in cancer

B7 homolog 3 (B7-H3, also called CD276) is a checkpoint of B7 family that is aberrantly and consistently expressed in several human cancers, and its overexpression correlates with weak prognosis. B7-H3 is expressed on a number of cells, and it acts as a driver of immune evasion. This is mediated through hampering T cell infiltration and promoting exhaustion of CD8⁺ T cells. Increased B7-H3 activity also promotes macrophage polarity toward pro-tumor type 2 (M2) phenotype. In addition, high B7-H3 activity induces aberrant angiogenesis to promote hypoxia, a result of which is resistance to common immune checkpoint inhibitor (ICI) therapy. This is mediated through the impact of hypoxia on dampening CD8⁺ T cell recruitment into tumor area. The immunosuppressive property of B7-H3 offers insights into targeting this checkpoint as a desired approach in cancer immunotherapy. B7-H3 can be a target in blocking monoclonal antibodies (mAbs), combination therapies, chimeric antigen receptor-modified T (CAR-T) cells and bispecific antibodies.

An optimized IgG-based B7-H3xCD3 bispecific antibody for treatment of gastrointestinal cancers

T cell-based immunotherapy has revolutionized oncological treatment. However, many patients do not respond to treatment, and long-term remissions remain rare, particularly in gastrointestinal cancers like colorectal cancer (CRC). B7-H3 is overexpressed in multiple cancer entities including CRC on both tumor cells and tumor vasculature, the latter facilitating influx of effector cells into the tumor site upon therapeutic targeting. We generated a panel of T cell-recruiting B7-H3xCD3 bispecific antibodies (bsAbs) and show that targeting a membrane-proximal B7-H3 epitope allows for a 100-fold reduction of CD3 affinity. In vitro, our lead compound CC-3 showed superior tumor cell killing, T cell activation, proliferation, and memory formation, whereas undesired cytokine release was reduced. In vivo, CC-3 mediated potent antitumor activity in three independent models using immunocompromised mice adoptively transferred with human effector cells with regard to prevention of lung metastasis and flank tumor growth as well as elimination of large established tumors. Thus, fine-tuning of both target and CD3 affinities as well as binding epitopes allowed for the generation of a B7-H3xCD3 bsAbs with promising therapeutic activity. CC-3 is presently undergoing good manufacturing practice (GMP) production to enable evaluation in a clinical "first-in-human" study in CRC.

New frontiers in immune checkpoint B7-H3 (CD276) research and drug development

B7-H3 (CD276), a member of the B7 family of proteins, is a key player in cancer progression. This immune checkpoint molecule is selectively expressed in both tumor cells and immune cells within the tumor microenvironment. In addition to its immune checkpoint function, B7-H3 has been linked to tumor cell proliferation, metastasis, and therapeutic resistance. Furthermore, its drastic difference in protein expression levels between normal and tumor tissues suggests that targeting B7-H3 with drugs would lead to cancer-specific toxicity, minimizing harm to healthy cells. These properties make B7-H3 a promising target for cancer therapy.Recently, important advances in B7-H3 research and drug development have been reported, and these new findings, including its involvement in cellular metabolic reprograming, cancer stem cell enrichment, senescence and obesity, have expanded our knowledge and understanding of this molecule, which is important in guiding future strategies for targeting B7-H3. In this review, we briefly discuss the biology and function of B7-H3 in cancer development. We emphasize more on the latest findings and their underlying mechanisms to reflect the new advances in B7-H3 research. In addition, we discuss the new improvements of B-H3 inhibitors in cancer drug development.

Integrated analysis of cervical squamous cell carcinoma cohorts from three continents reveals conserved subtypes of prognostic significance

Human papillomavirus (HPV)-associated cervical cancer is a leading cause of cancer deaths in women. Here we present an integrated multi-omic analysis of 643 cervical squamous cell carcinomas (CSCC, the most common histological variant of cervical cancer), representing patient populations from the USA, Europe and Sub-Saharan Africa and identify two CSCC subtypes (C1 and C2) with differing prognosis. C1 and C2 tumours can be driven by either of the two most common HPV types in cervical cancer (16 and 18) and while HPV16 and HPV18 are overrepresented among C1 and C2 tumours respectively, the prognostic difference between groups is not due to HPV type. C2 tumours, which comprise approximately 20% of CSCCs across these cohorts, display distinct genomic alterations, including loss or mutation of the STK11 tumour suppressor gene, increased expression of several immune checkpoint genes and differences in the tumour immune microenvironment that may explain the shorter survival associated with this group. In conclusion, we identify two therapy-relevant CSCC subtypes that share the same defining characteristics across three geographically diverse cohorts.

Human papillomavirus (HPV) is a known cause of cervical cancer. Here, the authors perform a multi-omic analysis using published cervical squamous cell carcinoma cohorts from the USA, Europe, and SubSaharan Africa and identify two cervical squamous cell carcinoma subtypes that display prognostic differences.

Immune checkpoint inhibitors as mediators for immunosuppression by cancer-associated fibroblasts: A comprehensive review

The tumor microenvironment (TME) is a significant contributor to cancer progression containing complex connections between cellular and chemical components and provides a suitable substrate for tumor growth and development. Growing evidence shows targeting tumor cells while ignoring the surrounding TME is not effective enough to overcome the cancer disease. Fibroblasts are essential sentinels of the stroma that due to certain conditions in TME, such as oxidative stress and local hypoxia, become activated, and play the prominent role in the physical support of tumor cells and the enhancement of tumorigenesis. Activated fibroblasts in TME, defined as cancer-associated fibroblasts (CAFs), play a crucial role in regulating the biological behavior of tumors, such as tumor metastasis and drug resistance. CAFs are highly heterogeneous populations that have different origins and, in addition to their role in supporting stromal cells, have multiple immunosuppressive functions via a membrane and secretory patterns. The secretion of different cytokines/chemokines, interactions that mediate the recruitment of regulatory immune cells and the reprogramming of an immunosuppressive function in immature myeloid cells are just a few examples of how CAFs contribute to the immune escape of tumors through various direct and indirect mechanisms on specific immune cell populations. Moreover, CAFs directly abolish the role of cytotoxic lymphocytes. The activation and overexpression of inhibitory immune checkpoints (iICPs) or their ligands in TME compartments are one of the main regulatory mechanisms that inactivate tumor-infiltrating lymphocytes in cancer lesions. CAFs are also essential players in the induction or expression of iICPs and the suppression of immune response in TME. Based on available studies, CAF subsets could modulate immune cell function in TME through iICPs in two ways; direct expression of iICPs by activated CAFs and indirect induction by production soluble and then upregulation of iICPs in TME. With a focus on CAFs’ direct and indirect roles in the induction of iICPs in TME as well as their use in immunotherapy and diagnostics, we present the evolving understanding of the immunosuppressive mechanism of CAFs in TME in this review. Understanding the complete picture of CAFs will help develop new strategies to improve precision cancer therapy.

To kill a cancer: Targeting the immune inhibitory checkpoint molecule, B7-H3

Targeting the anti-tumor immune response via the B7 family of immune-regulatory checkpoint proteins has revolutionized cancer treatment and resulted in punctuated responses in patients. B7-H3 has gained recent attention given its prominent deregulation and immunomodulatory role in a multitude of cancers. Numerous cancer studies have firmly established a strong link between deregulated B7-H3 expression and poorer outcomes. B7-H3 has been shown to augment cancer cell survival, proliferation, metastasis, and drug resistance by inducing an immune evasive phenotype through its effects on tumor-infiltrating immune cells, cancer cells, cancer-associated vasculature, and the stroma. Given the complex interplay between each of these components of the tumor microenvironment, a deeper understanding of B7-H3 signaling properties is inherently crucial to developing efficacious therapies that can target and inhibit these cancer-promoting interactions. This review delves into the various ways B7-H3 acts as an immunomodulator to facilitate immune evasion and promote tumor growth and spread. With post-transcriptional and post-translational modifications giving rise to different active isoforms coupled with recent discoveries of its putative receptors, B7-H3 can perform diverse functions. Here, we first discuss the dual co-stimulatory/co-inhibitory functions of B7-H3 in the context of normal physiology and cancer. We then discuss the crosstalk facilitated by B7-H3 between stromal components and tumor cells that promote tumor growth and metastasis in different populations of tumor cells, associated vasculature, and the stroma. Concurrently, we highlight therapeutic strategies that can exploit these interactions and their associated limitations, concluding with a special focus on the promise of next-gen in silico-based approaches to small molecule inhibitor drug discovery for B7-H3 that may mitigate these limitations.

Fight the Cancer, Hit the CAF!

Simple Summary

In the last 20 years, the tumor microenvironment (TME) has raised an increasing interest from the therapeutic point of view. Indeed, different strategies targeting either the endothelial or the immune component have been implemented. Furthermore, cancer-associated fibroblasts (CAF) have attracted even more interest due to their ability to prime the TME in order to favor tumor progression and metastasis. This current review provides a comprehensive overview on the latest discoveries regarding CAF, more specifically on their complex characterization and on preclinical studies and clinical trials that target CAF within the TME.

Abstract

The tumor microenvironment (TME) is comprised of different cellular components, such as immune and stromal cells, which co-operate in unison to promote tumor progression and metastasis. In the last decade, there has been an increasing focus on one specific component of the TME, the stromal component, often referred to as Cancer-Associated Fibroblasts (CAF). CAF modulate the immune response and alter the composition of the extracellular matrix with a decisive impact on the response to immunotherapies and conventional chemotherapy. The most recent publications based on single-cell analysis have underlined CAF heterogeneity and the unique plasticity that strongly impact the TME. In this review, we focus not only on the characterization of CAF based on the most recent findings, but also on their impact on the immune system. We also discuss clinical trials and preclinical studies where targeting CAF revealed controversial results. Therefore, future efforts should focus on understanding the functional properties of individual subtypes of CAF, taking into consideration the peculiarities of each pathological context.

Blockading a new NSCLC immunosuppressive target by pluripotent autologous tumor vaccines magnifies sequential immunotherapy

The presence of multiple immunosuppressive targets and insufficient activation and infiltration of cytotoxic T lymphocytes (CTLs) allow tumor cells to escape immune surveillance and disable anti-PD-1/PD-L1 immunotherapy. Nanobiotechnology-engineered autologous tumor vaccines (ATVs) that were camouflaged by tumor cell membrane (TCM) were designed to activate and facilitate CTLs infiltration for killing the unprotected lung tumor cells, consequently realizing the sequential immunotherapy. PDE5 was firstly screened out as a new immunosuppressive target of lung cancer in clinical practice. Immediately afterwards, phosphodiesterase-5 (PDE5) and programmed cell death 1 ligand 1 (PD-L1) dual-target co-inhibition was proposed to unfreeze the immunosuppressive microenvironment of NSCLC. Systematic studies validated that this ATVs-unlocked sequential immunotherapy after co-encapsulating PDE5 inhibitor and NO donor (i.e., l-arginine) exerted robust anti-tumor effects through increasing inducible nitric oxide synthase (iNOS) expression, blockading PDE5 pathway and activating systematic immune responses, which synergistically eradicated local and abscopal lung cancers in either orthotopic or subcutaneous models. The pluripotent ATVs that enable PDE5 inhibition and sequential immunotherapy provide a new avenue to mitigate immunosuppressive microenvironment and magnify anti-PD-1/PD-L1 immunotherapy.

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A clinically-screened NSCLC immunosuppressive target (PDE5) is experimentally validated available for designing new drugs.

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Pluripotent ATVs unlock sequential immunotherapy via PDE5&PD-L1 co-inhibition and TCM antigens-arised immune activation.

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NO donor loaded in ATVs augmented PDE5i efficacy and magnified sequential immunotherapy along with TCM-enabled tumor tropism.

Prognostic values of B7-H3, B7-H4, and HHLA2 expression in human pancreatic cancer tissues based on mIHC and spatial distribution analysis

BACKGROUND

Pancreatic cancer (PC) is one of the most malignant solid tumors and its 5-year survival rate remains poor. Although immunotherapy has achieved certain therapeutic efficacy in some clinical trials, such treatment still shows low responses and overall remission rate. Therefore, it is urgently necessary to dissect the tumor microenvironment and optimize the immunotherapeutic strategies against this malignancy.

METHODS

Using the multi-color immunohistochemistry assay, we investigated the expressions of B7-H3, B7-H4, HHLA2, CD8, and CD68 in 63 cases of PC tissues in a tissue microarray. Moreover, we analyzed immunolocalization features, clinical associations and prognostic values of these molecules.

RESULTS

The expressions of B7-H3, B7-H4, and HHLA2 could be detected in cytokeratin staining positive (CK+) cancer epithelial cells, CD68+tumor-associated macrophages (TAMs), and even other cells defined as CK-CD8-CD68-. Higher expression of B7-H3 in tumor cells could predict a better survival of the PC patients. A positive correlation was found between the expressions of B7-H3 and HHLA2 in tumor cells, while there was a negative correlation between the expressions of B7-H4 and HHLA2 in tumor cells. A positive correlation was found between the expressions of B7-H3 and B7-H4 or HHLA2 in CD68+TAMs, but not B7-H4 and HHLA2. Tumor-infiltrating CD8+T cells in combination with CD68+TAMs could serve as an important predictor for the postoperative prognosis of PC patients. Higher expression of B7-H3, or HHLA2 in CD68+TAMs could serve as an important predictor for poorer prognosis of PC patients. Patients with B7-H3lowB7-H4low, B7-H3lowHHLA2low, or B7-H4lowHHLA2low on CD68+TAMs could have a better postoperative prognosis compared with the other sub-populations in the combinational analysis.

CONCLUSIONS

Taken together, our study indicated variable expressions and prognostic values of B7-H3, B7-H4, and HHLA2, in human PC tissues, and demonstrated that these co-stimulator molecules expressed by CD68+TAMs could be used as important bio-markers for the prognostic prediction of PC patients. Moreover, these results supported that the evaluation of these markers could be used as essential candidate targets for immunotherapy against PC.

The Immunological Contribution of a Novel Metabolism-Related Signature to the Prognosis and Anti-Tumor Immunity in Cervical Cancer

Cervical cancer is the most frequently diagnosed malignancy in the female reproductive system. Conventional stratification of patients based on clinicopathological characters has gradually been outpaced by a molecular profiling strategy. Our study aimed to identify a reliable metabolism-related predictive signature for the prognosis and anti-tumor immunity in cervical cancer. In this study, we extracted five metabolism-related hub genes, including ALOX12B, CA9, FAR2, F5 and TDO2, for the establishment of the risk score model. The Kaplan-Meier curve suggested that patients with a high-risk score apparently had a worse prognosis in the cervical cancer training cohort (TCGA, n = 304, p < 0.0001), validation cohort (GSE44001, n = 300, p = 0.0059) and pan-cancer cohorts (including nine TCGA tumors). Using a gene set enrichment analysis (GSEA), we observed that the model was correlated with various immune-regulation-related pathways. Furthermore, pan-cancer cohorts and immunohistochemical analysis showed that the infiltration of tumor infiltrating lymphocytes (TILs) was lower in the high-score group. Additionally, the model could also predict the prognosis of patients with cervical cancer based on the expression of immune checkpoints (ICPs) in both the discovery and validation cohorts. Our study established and validated a metabolism-related prognostic model, which might improve the accuracy of predicting the clinical outcome of patients with cervical cancer and provide guidance for personalized treatment.

Innate Lymphoid Cells: Role in Immune Regulation and Cancer

Simple Summary

Innate lymphoid cells (ILCs) are an emerging family of effector cells known to play a major role in innate defenses against pathogens, lymphoid organogenesis, tissue repair, and homeostasis. They are positioned strategically within tissues to provide the first line of defence and shape the ensuing adaptive immune cell response. Recent evidence suggests that ILCs contribute to immune regulation in different diseases, including cancer, and can have significant impact on disease outcome. In this review, we highlight the immunosuppressive roles of ILCs in cancer that inhibit effective immune surveillance and anti-tumour response.

Abstract

Immune regulation is composed of a complex network of cellular and molecular pathways that regulate the immune system and prevent tissue damage. It is increasingly clear that innate lymphoid cells (ILCs) are also armed with immunosuppressive capacities similar to well-known immune regulatory cells (i.e., regulatory T cells). In cancer, immunoregulatory ILCs have been shown to inhibit anti-tumour immune response through various mechanisms including: (a) direct suppression of anti-tumour T cells or NK cells, (b) inhibiting T-cell priming, and (c) promoting other immunoregulatory cells. To provide a framework of understanding the role of immunosuppressive ILCs in the context of cancer, we first outline a brief history and challenges related to defining immunosuppressive ILCs. Furthermore, we focus on the mechanisms of ILCs in suppressing anti-tumour immunity and consequentially promoting tumour progression.

Combination Blockade of the IL6R/STAT-3 Axis with TIGIT and Its Impact on the Functional Activity of NK Cells against Prostate Cancer Cells

Background/Aims. Prostate cancer (PCa) is one of the neoplasms with the highest incidence and mortality rate in men worldwide. Advanced stages of the disease are usually very aggressive, and most are treated with chemotherapeutic drugs that generally cause side effects in these patients. However, additional therapeutic targets such as the IL6R/STAT-3 axis and TIGIT have been proposed, mainly due to their relevance in the development of PCa and regulation of NK cell-mediated cytotoxicity. Here, we evaluate the effect of inhibitors directed against these therapeutic targets primarily via an analysis of NK cell function versus prostate cancer cells. Methods. We analyzed the secretion of cytokines, chemokines, and growth factors in 22Rv1, LNCaP, and DU145 cells. In these cells, we also evaluated the expression of NK ligands, IL6R, STAT-3, and phosporylated STAT-3. In NK-92 cells, we evaluated the effects of Stattic (Stt) and tocilizumab (Tcz) on NK receptors. In addition, we assessed if the disruption of the IL6R/STAT-3 pathway and blockade of TIGIT potentiated the cytotoxicity of NK-92 cells versus DU145 cells. Results. DU145 abundantly secretes M-CSF, VEGF, IL-6, CXCL8, and TGF-β. Furthermore, the expression of CD155 was found to increase in accordance with aggressiveness and metastatic status in the prostate cancer cells. Stt and Tcz induce a decrease in STAT-3 phosphorylation in the DU145 cells and, in turn, induce an increase of NKp46 and a decrease of TIGIT expression in NK-92 cells. Finally, the disruption of the IL6R/STAT-3 axis in prostate cancer cells and the blocking of TIGIT on NK-92 were observed to increase the cytotoxicity of NK-92 cells against DU145 cells through an increase in sFasL, granzyme A, granzyme B, and granulysin. Conclusions. Our results reveal that the combined use of inhibitors directed against the IL6R/STAT-3 axis and TIGIT enhances the functional activity of NK cells against castration-resistant prostate cancer cells.

Multi-target combinatory strategy to overcome tumor immune escape

Immune therapy has become the fourth approach after surgery, chemotherapy, and radiotherapy in cancer treatment. Many immune checkpoints were identified in the last decade since ipilimumab, which is the first immune checkpoint inhibitor to cytotoxic T-lymphocyte associated protein 4, had been approved by the US Food and Drug Administration (FDA) for the treatment of unresectable or metastatic melanoma in 2011. The use of several antibody drugs that target PD1/PD-L1 for various cancer treatments has been approved by the FDA. However, fewer people are benefitting from immune checkpoint inhibitor treatment in solid cancers. Approximately 80% of patients do not respond appropriately because of primary or acquired therapeutic resistance. Along with the characterization of more immune checkpoints, the combinatory treatment of multiimmune checkpoint inhibitors becomes a new option when monotherapy could not receive a good response. In this work, the author focuses on the combination therapy of multiple immune checkpoints (does not include targeted therapy of oncogenes or chemotherapy), introduces the current progression of multiple immune checkpoints and their related inhibitors, and discusses the advantages of combination therapy, as well as the risk of immune-related adverse events.

Immune Subtypes Characterization Identifies Clinical Prognosis, Tumor Microenvironment Infiltration, and Immune Response in Ovarian Cancer

Objective: Because of the modest immunotherapeutic response among ovarian carcinoma (OC) patients, it is significant to evaluate antitumor immune response and develop more effective precision immunotherapeutic regimens. Here, this study aimed to determine diverse immune subtypes of OC.

Methods: This study curated the expression profiles of prognostic immunologically relevant genes and conducted consensus clustering analyses for determining immune subtypes among OC patients in TCGA cohort. With Boruta algorithm, characteristic genes were screened for conducting an immune scoring system through principal component analysis algorithm. The single-sample gene set enrichment analysis and ESTIAMTE methods were adopted for quantifying the immune infiltrates and responses to chemotherapeutic agents were estimated with pRRophetic algorithm. Two immunotherapeutic cohorts were used for investigating the efficacy of immune score in predicting therapeutic benefits.

Results: Two immune subtypes were conducted among 377 OC patients. Immune subtype 2 was characterized by worse clinical prognosis, more frequent genetic variations and mutations, enhanced immune infiltrates, and increased expression of MHC molecules and programmed cell death protein 1/programmed death ligand 1 (PD-1/PD-L1). In total, 30 prognosis-relevant characteristic immune subtype–derived genes were identified for constructing the immune score of OC patients. High immune score was linked with more dismal prognosis, decreased immune infiltrations, and expression of MHC molecules. High immune score presented favorable sensitivity to doxorubicin and vinorelbine and reduced sensitivity to cisplatin. In addition, immune score possessed the potential in predicting benefits from anti–PD-1/PD-L1 therapy.

Conclusion: Collectively, our findings propose two complex and diverse immune subtypes of OC. Quantitative assessment of immune subtypes in individual patients strengthens the understanding of tumor microenvironment features and promotes more effective immunotherapeutic regimens.

Coexpression of HHLA2 and PD-L1 on Tumor Cells Independently Predicts the Survival of Spinal Chordoma Patients

Background

Immunotherapy only achieves efficacy in some cancer patients, and less is known about other immune checkpoint molecules in chordoma. Here, we aimed to determine the expression of PD-L1, HHLA2, B7H3, IDO-1 and Galectin-9 in spinal chordoma and evaluated their association with tumor infiltrating lymphocytes (TILs), clinicopathological characteristics and survival of patients.

Methods

Using multiplexed quantitative immunofluorescence (QIF), we simultaneously measured the levels of five different immune checkpoint molecules and major TIL subsets in 92 human spinal chordoma samples.

Results

Tumor HHLA2 and PD-L1 were positive in 80.0% and 86.0% of cases, respectively. However, B7H3, IDO-1 and Galectin-9 positivity on tumor cells were only seen in 21.0% of cases, despite all showing predominantly stromal expression. Coexpression of these QIF markers in the tumor compartment was scarcely detected except for PD-L1 and HHLA2, which was observed in 69.6% of cases. While tumoral HHLA2 and stromal B7H3 expressions were associated with an aggressive tumor phenotype, suppressive immune response (specifically including elevated PD-1⁺ TILs level and decreased CD8⁺ TIL density) and poor prognosis, stromal levels of PD-L1 and Galectin-9 predicted the opposite outcomes. Importantly, HHLA2 and PD-L1 coexpression on tumor cells independently predicted both worse local recurrence-free survival and overall survival.

Conclusion

These data provide a better understanding of the immunosuppressive mechanism in chordoma and may be useful for the development of combination or novel immunotherapy approaches aiming to improve therapeutic efficacy and survival.

Single-cell tumor-immune microenvironment of BRCA1/2 mutated high-grade serous ovarian cancer

The majority of high-grade serous ovarian cancers (HGSCs) are deficient in homologous recombination (HR) DNA repair, most commonly due to mutations or hypermethylation of the BRCA1/2 genes. We aimed to discover how BRCA1/2 mutations shape the cellular phenotypes and spatial interactions of the tumor microenvironment. Using a highly multiplex immunofluorescence and image analysis we generate spatial proteomic data for 21 markers in 124,623 single cells from 112 tumor cores originating from 31 tumors with BRCA1/2 mutation (BRCA1/2mut), and from 13 tumors without alterations in HR genes. We identify a phenotypically distinct tumor microenvironment in the BRCA1/2mut tumors with evidence of increased immunosurveillance. Importantly, we report a prognostic role of a proliferative tumor-cell subpopulation, which associates with enhanced spatial tumor-immune interactions by CD8+ and CD4 + T-cells in the BRCA1/2mut tumors. The single-cell spatial landscapes indicate distinct patterns of spatial immunosurveillance with the potential to improve immunotherapeutic strategies and patient stratification in HGSC.

The tumour microenvironment has not been fully characterised in high-grade serous ovarian cancers (HGSOC). Here, the authors use highly multiplexed imaging to analyse the HGSOC immune microenvironment at spatial and single-cell resolution, with clinically relevant findings for BRCA1/2-mutated tumours.

The prognosis biomarkers based on m6A-related lncRNAs for myeloid leukemia patients

Background

Chronic myeloid leukemia (CML) and acute myeloid leukemia (AML) are two common malignant disorders in leukemia. Although potent drugs are emerging, CML and AML may still relapse after the drug treatment is stopped. N6-methyladenosine (m6A) and lncRNAs play certain roles in the occurrence and development of tumors, but m6A-modified LncRNAs in ML remain to be further investigated.

Methods

In this study, we extracted and analyzed the TCGA gene expression profile of 151 ML patients and the clinical data. On this basis, we then evaluated the immune infiltration capacity of ML and LASSO-penalized Cox analysis was applied to construct the prognostic model based on m6A related lncRNAs to verify the prognostic risk in clinical features of ML. Quantitative reverse transcription PCR was used to detect the expression level of LncRNA in in ML cell lines K562, MOLM13 and acute monocytic leukemia cell line THP-1.

Results

We found 70 m6A-related lncRNAs that were related to prognosis, and speculated that the content of stromal cells and immune cells would correlate with the survival of patients with ML. Next, Prognostic risk model of m6A-related lncRNAs was validated to have excellent consistency in clinical features of ML. Finally, we verified the expression levels of CRNDE, CHROMR and NARF-IT1 in ML cell lines K562, MOLM13 and acute monocytic leukemia cell line THP-1, which were significant.

Conclusions

The research provides clues for the prognosis prediction of ML patients by using the m6A-related lncRNAs model we have created, and clarifies the accuracy and authenticity of it.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02428-3.

Cancer-associated fibroblasts as accomplices to confer therapeutic resistance in cancer

The "seed and soil" concept has reformed paradigms for cancer treatment in the past decade. Accumulating evidence indicates that the intimate crosstalk between cancer cells and stromal cells plays a tremendous role in tumor progression. Cancer-associated fibroblasts (CAFs), the largest population of stroma cells, influence therapeutic effects through diverse mechanisms. Herein, we summarize the recent advances in the versatile functions of CAFs regarding their heterogeneity, and we mainly discuss the pro-tumorigenic functions of CAFs which promote tumorigenesis and confer therapeutic resistance to tumors. Targeting CAFs is emerging as one of the most appealing strategies in anticancer therapies. The endeavors to target or reprogram the specific subtypes of CAFs provide great cancer treatment opportunities, which may provide a better clinical benefit to cancer patients.

Comprehensive Analysis of the Potential Immune-Related Biomarker Transporter Associated With Antigen Processing 1 That Inhibits Metastasis and Invasion of Ovarian Cancer Cells

Transporter associated with antigen processing 1 (TAP1) is a protein related immune regulation and plays a role in several malignant tumors. However, the effect of TAP1 on immune infiltration, immunotherapy, and metastasis in different cancers has not been reported till date. The cancer genome atlas database, the tumor immune estimation resource database, and the estimation of stromal and immune cells in malignant tumors using expression (ESTIMATE) algorithm were used to determine the correlation between TAP1 expression and the prognosis of a variety of cancers, immune infiltration, immune checkpoint genes, DNA methylation, and neoantigens. Various enrichment analyses were used to study the correlation between TAP1 and key transcription factors using the Kyoto encyclopedia of genes and genomes (KEGG) pathway in ovarian cancer. Immunological methods were used to evaluate the expression of TAP1 protein in ovarian and cervical cancer, and Kaplan-Meier analysis was used to analyze the prognostic value of TAP1. RNA interference (RNAi) was used to verify the effect of TAP1 on ovarian cancer. Compared with normal tissues, cancer tissues showed a significant increase in the expression of TAP1, and TAP1 expression was related to the poor prognosis of cancers such as ovarian cancer. The expression level of TAP1 was correlated with immune checkpoint genes, DNA methylation, tumor mutation burden, microsatellite instability, and neoantigens in various cancers. Our results showed that TAP1 was upregulated in ovarian cancer cell lines and was associated with poor prognosis. Further, we verified the expression of TAP1-related transcription factors (MEF2A and LEF1) and found that TAP1 was closely related to ovarian cancer metastasis in vitro and in vivo. These results indicated that TAP1 could be used as a biomarker for the diagnosis and prognosis of cancer and as a new therapeutic target.

DNA Methylation Modification Map to Predict Tumor Molecular Subtypes and Efficacy of Immunotherapy in Bladder Cancer

Background: Considering the heterogeneity and complexity of epigenetic regulation in bladder cancer, the underlying mechanisms of global DNA methylation modification in the immune microenvironment must be investigated to predict the prognosis outcomes and clinical response to immunotherapy. Methods: We systematically assessed the DNA methylation modes of 985 integrated bladder cancer samples with the unsupervised clustering algorithm. Subsequently, these DNA methylation modes were analyzed for their correlations with features of the immune microenvironment. The principal analysis algorithm was performed to calculate the DMRscores of each samples for qualification analysis. Findings: Three DNA methylation modes were revealed among 985 bladder cancer samples, and these modes are related to diverse clinical outcomes and several immune microenvironment phenotypes, e.g., immune-desert, immune-inflamed, and immune-excluded ones. Then patients were classified into high- and low-DMRscore subgroups according to the DMRscore, which was calculated based on the expression of DNA methylation related genes (DMRGs). Patients with the low-DMRscore subgroup presented a prominent survival advantage that was significantly correlated to the immune-inflamed phenotype. Further analysis revealed that patients with low DMRscores exhibited less TP53 wild mutation, lower cancer stage and molecular subtypes were mainly papillary subtypes. In addition, an independent immunotherapy cohort confirmed that DMRscore could serve as a signature to predict prognosis outcomes and immune responses. Conclusion: Global DNA methylation modes can be used to predict the immunophenotypes, aggressiveness, and immune responses of bladder cancer. DNA methylation status assessments will strengthen our insights into the features of the immune microenvironment and promote the development of more effective treatment strategies.

The role of B7-H3 in tumors and its potential in clinical application

B7-H3 (CD276 molecule) is an immune checkpoint from the B7 family of molecules that acts more as a co-inhibitory molecule to promote tumor progression. It is abnormally expressed on tumor cells and can be induced to express on antigen-presenting cells (APCs) including dendritic cells (DCs) and macrophages. In the tumor microenvironment (TME), B7-H3 promotes tumor progression by impairing T cell response, promoting the polarization of tumor-associated macrophages (TAMs) to M2, inhibiting the function of DCs, and promoting the migration and invasion of cancer-associated fibroblasts (CAFs). In addition, through non-immunological functions, B7-H3 promotes tumor cell proliferation, invasion, metastasis, resistance, angiogenesis, and metabolism, or in the form of exosomes to promote tumor progression. In this process, microRNAs can regulate the expression of B7-H3. B7-H3 may serve as a potential biomarker for tumor diagnosis and a marker of poor prognosis. Immunotherapy targeting B7-H3 and the combination of B7-H3 and other immune checkpoints have shown certain efficacy. In this review, we summarized the basic characteristics of B7-H3 and its mechanism to promote tumor progression by inducing immunosuppression and non-immunological functions, as well as the potential clinical applications of B7-H3 and immunotherapy based on B7-H3.

Expression of B7-H3 Correlates with PD-L1 and Poor Prognosis in Patients with Cervical Cancer

Purpose

The purpose of this study was to investigate B7 homolog 3 (B7-H3) expression patterns and define its associations with programmed cell-death ligand 1 (PD-L1), pathological features, and survival in patients with cervical cancer.

Patients and Methods

Immunohistochemical staining was used to investigate B7-H3 and PD-L1 expression in tissue microarrays from 552 patients with stage IB1 and IIA1 cervical cancer, including 406 with squamous cell carcinoma and 146 with endocervical adenocarcinoma.

Results

B7-H3 was expressed in the tumor cells (TCs) of 32.1% of the samples as well as in the stromal cells of 92.9% of the specimens. B7-H3 was co-expressed with PD-L1 in 21.0% of the samples, while only one or the other was expressed in 41.7% of the samples. B7-H3 expression in TCs was more frequent in squamous cell carcinoma, PD-L1-positive samples, and tissues from patients with lymph node metastasis; moreover, its expression was an independent predictor of shorter survival.

Conclusion

B7-H3 positivity in TCs is a promising prognostic biomarker, and targeting B7-H3 alone or in combination with PD-1/PD-L1 may be a potential immunotherapeutic strategy for patients with cervical cancer.

B7-H3/CD276: An Emerging Cancer Immunotherapy

Immunotherapy aiming at suppressing tumor development by relying on modifying or strengthening the immune system prevails among cancer treatments and points out a new direction for cancer therapy. B7 homolog 3 protein (B7-H3, also known as CD276), a newly identified immunoregulatory protein member of the B7 family, is an attractive and promising target for cancer immunotherapy because it is overexpressed in tumor tissues while showing limited expression in normal tissues and participating in tumor microenvironment (TME) shaping and development. Thus far, numerous B7-H3-based immunotherapy strategies have demonstrated potent antitumor activity and acceptable safety profiles in preclinical models. Herein, we present the expression and biological function of B7-H3 in distinct cancer and normal cells, as well as B7-H3-mediated signal pathways in cancer cells and B7-H3-based tumor immunotherapy strategies. This review provides a comprehensive overview that encompasses B7-H3’s role in TME to its potential as a target in cancer immunotherapy.

Cancer-Associated Fibroblasts: Implications for Cancer Therapy

Tumour cells do not exist as an isolated entity. Instead, they are surrounded by and closely interact with cells of the environment they are emerged in. The tumour microenvironment (TME) is not static and several factors, including cancer cells and therapies, have been described to modulate several of its components. Fibroblasts are key elements of the TME with the capacity to influence tumour progression, invasion and response to therapy, which makes them attractive targets in cancer treatment. In this review, we focus on fibroblasts and their numerous roles in the TME with a special attention to recent findings describing their heterogeneity and role in therapy response. Furthermore, we explore how different therapies can impact these cells and their communication with cancer cells. Finally, we highlight potential strategies targeting this cell type that can be employed for improving patient outcome.

Characterization of immune infiltration in sarcomatoid hepatocellular carcinoma

Sarcomatoid hepatocellular carcinoma (sHCC) is a rare type of liver malignancy. Currently, the tumor immune features of sHCC are poorly understood. We recruited 31 patients with resected sHCC for whom tissue samples and complete clinicopathologic and follow-up data were available. To understand the immune infiltration of sHCC, immunohistochemical staining was performed on the resected sHCC samples to compare the expressions of programmed death-1 (PD-1), programmed death-ligand 1 (PD-L1), B7-H3, indoleamine 2,3-dioxygenase (IDO), lymphocyte-activation gene 3 (LAG-3), CD8, FOXP3, and CD68 in tumor and peritumoral tissues. Kaplan-Meier and Cox regression analyses were used to assess the predictive value of immune markers. Sarcomatoid components were characterized with significantly higher expression of PD-L1 and B7-H3 in tumor cells than in conventional HCC components, as well as in peritumoral tissue. Additionally, sarcomatoid components had a higher density of FOXP3⁺ and LAG-3⁺ cells and a lower density of CD8⁺ cells than conventional HCC components or peritumoral tissue. Higher expression of PD-L1 in tumor cells significantly correlated with higher densities of CD8⁺, PD-1⁺, and LAG-3⁺ cells. Increased tumor PD-L1 expression and decreased CD8⁺ T-cell density were associated with poor overall survival (OS) and disease-free survival (DFS) in patients of sHCC. These findings suggest further characterization on relative mechanism of sHCC immune infiltration may identify therapeutic targets for immunotherapy.

Glycosylation of Siglec15 promotes immunoescape and tumor growth

Siglec15 is a recently characterized immunosuppressive transmembrane protein, which expresses in various types of solid tumors and promotes cancer development. Several studies reported that Siglec15 is a prognostic biomarker of cancer patients, and targeting Siglec15 may be a promising strategy for cancer therapy. However, the regulation of Siglec15 function remains unclear. Here we show that the immunosuppression activity of Siglec15 is largely modulated by N-glycosylation. Through mass spectrum and site mutation analysis, we identified that Siglec15 was extensively glycosylated at N172 (N173 for mouse) in cancer cells. Meanwhile, Siglec15 N172Q had a similar molecular weight with PNGase-F-treated Siglec15, suggesting N172 as the only one glycosylation residue. In xenograft model, glycosylation deficiency of Siglec15 reduced tumor growth in C57BL/6 mice, but had no impact in nude mice, indicating the requirement of N-glycosylation for immunosuppressive function of Siglec15. Furthermore, colorectal cancer patients with high Siglec15 expression had a poor response to neoadjuvant chemo-radiotherapy and short survival time. Interestingly, removal of N-glycosylation enhances the detection of Siglec15, which may be employed in the prediction of immunotherapy response. Together, our results disclose a pivotal role of glycosylated Siglec15 in tumor immune escape, which may be a therapeutic target for cancer immunotherapy.

B7-H3 on breast cancer cell MCF7 inhibits IFN-γ release from tumour-infiltrating T cells

B7-H3 is a type I membrane protein that has contradictory co-stimulatory and co-inhibitory effects in adaptive and anti-tumour immunity. B7-H3 is up-regulated in many malignant tumours, including breast cancer. Therefore, we hypothesise that B7-H3, which has an immunosuppressive role, suppresses anti-tumour immunity. The aim of this study was to clarify the role of B7-H3 in the tumor microenvironment in breast cancer, explore the possibility of B7-H3 as a target for clinical immunotherapy, and provide reference for clinical work. We knocked down B7-H3 with siRNA in MCF7 breast cancer cells, which we termed MCF7-B7-H3-KD cells, and the expression of B7-H3 was assessed by flow cytometry. GAPDH (glyceraldehyde-3-phosphate dehydrogenase) knockdown was used as a control (MCF7-Gapdh). MCF7-B7-H3-KD and MCF7-Gapdh cells were co-cultured with peripheral blood mononuclear cells (PBMCs) and CD3⁺ T cells from healthy donors to assess the effect of B7-H3 loss. PBMCs cultured with MCF7-Gapdh cells showed decreased activation, proliferation, and function of CD8⁺ T cells, but there was no effect on the proliferation of CD4⁺ T cells. However, when MCF7-B7-H3-KD cells were co-cultured with PBMCs, the proliferation ability of CD4⁺ T cells and CD8⁺ T cells was significantly higher than that observed in MCF7-Gapdh cell co-culture. Additionally, co-culture with MCF7-Gapdh cells decreased the expression of IFN-γ (Interferon-γ). However, after co-culture with MCF7-B7-H3-KD cells, there was an increase in IFN-γ. We further found that this inhibitory effect on IFN-γ was because of decreased mTOR (the mammalian target of rapamycin) phosphorylation in T cells. Treatment of T cells co-cultured with MCF7-B7-H3-KD cells with an mTOR inhibitor blocked the secretion of IFN-γ. B7-H3 on tumour cells inhibits the proliferation of CD4⁺ and CD8⁺ T cells and inhibits the release of IFN-γ by decreasing mTOR signalling. A better understanding of these complex immune regulatory mechanisms should facilitate the generation of more powerful and selective tools to manipulate cancer therapy.

Expression, regulation and clinical significance of B7-H3 on neutrophils in human gastric cancer

Neutrophils are conspicuous components of gastric cancer (GC) tumors, increasing with tumor progression and poor patient survival. However, the phenotype, regulation and clinical relevance of neutrophils in human GC are presently unknown. Most intratumoral neutrophils showed an activated CD54⁺ phenotype and expressed high level B7-H3. Tumor tissue culture supernatants from GC patients induced the expression of CD54 and B7-H3 on neutrophils in time-dependent and dose-dependent manners. Locally enriched CD54⁺ neutrophils and B7-H3⁺ neutrophils positively correlated with increased granulocyte-macrophage colony stimulating factor (GM-CSF) detection ex vivo; and in vitro GM-CSF induced the expression of CD54 and B7-H3 on neutrophils in both time-dependent and dose-dependent manners. Furthermore, GC tumor-derived GM-CSF activated neutrophils and induced neutrophil B7-H3 expression via JAK-STAT3 signaling pathway activation. Finally, intratumoral B7-H3⁺ neutrophils increased with tumor progression and independently predicted reduced overall survival. Collectively, these results suggest B7-H3⁺ neutrophils to be potential biomarkers in GC.

Cancer Cell B7-H3 Expression Is More Prevalent in the Pancreato-Biliary Subtype of Ampullary Cancer Than in Pancreatic Cancer

B7-H3 is an immunomodulatory member of the B7-superfamily with limited expression in normal tissues, but overexpression in several types of cancer. Therefore it is currently being explored as a potential target for cancer immunotherapy. The biological relevance of B7-H3 expression in pancreatic cancer is unclear, while there are no data on B7-H3 expression in ampullary cancer. We aimed to compare intra-tumoral B7-H3 expression between these two closely related cancer types and analyze its association with post-surgical disease course. B7-H3 expression levels were determined by immunohistochemistry in tissue microarrays of resected tumors of 137 pancreatic cancer patients and 83 patients with ampullary cancer of the pancreato-biliary subtype. B7-H3 was more frequently expressed in cancer cells of ampullary cancer patients compared to pancreatic cancer patients (51% versus 21%; p< 0.001). In ampullary cancer patients, but not in pancreatic cancer patients, B7-H3 cancer cell expression was associated with longer disease-free survival and patient survival. However, the prognostic value of B7-H3 was lost upon adjustment for CA19-9 levels. The frequencies of B7-H3 expression in tumor stroma did not differ between the two types of cancer (66% versus 63%). In both cancer types, stromal B7-H3 expression was not associated with post-surgical disease course. Compared to pancreatic cancer, B7-H3 is more frequently expressed in cancer cells of patients with the pancreato-biliary subtype of ampullary cancer. These data suggest that B7-H3 may represent an interesting potential target for immunotherapy in ampullary cancer rather than in pancreatic cancer.

Expression of B7-H4 and IDO1 is associated with drug resistance and poor prognosis in high-grade serous ovarian carcinomas

High-grade serous ovarian carcinoma (HGSC) is the most lethal gynecologic malignancy. While immune checkpoint inhibitors against PD-L1 and CTLA-4 have shown significant effects in multiple tumor types, the response rate to single-agent immune checkpoint inhibitors is low in HGSC. Alternative biomarkers and targets must be identified to guide patient selection and new therapeutic strategies in HGSC. Here, we aim to investigate the clinical significance of novel immune modulators, including B7-H4, IDO1, Tim3, IL6, and IL-8, in patients with HGSC. A total of 48 patients with HGSCs, comprising 24 cases that were sensitive and 24 that were resistant to standard paclitaxel and carboplatin chemotherapy, were selected for our initial analysis. A NanoString assay including 33 immune-related genes was used to compare the expression of different immune regulatory molecules in the sensitive and resistant groups. Differentially expressed proteins were verified using multiplex immunohistochemical staining on tissue arrays of 202 patients with HGSCs who underwent primary surgery at MDACC. We analyzed the expression levels of immune checkpoints and compared expression profiles with clinicopathologic features including response, progression-free survival, and overall survival. HGSC tumors resistant to therapy expressed higher levels of B7-H4 (69.3%), IDO1 (71.8%), Tim3 (89.1%), and inflammatory factors IL-6 and IL-8, and expressed higher Tim3 in stromal components. High expression of B7-H4 and IDO1 was associated with significantly lower overall survival and progression-free survival. B7-H4 and IDO1 were co-expressed in 49.1% of studied cases. A panel of immunomodulatory proteins including B7-H4, IDO1, Tim3, IL-6, and IL-8 are expressed at high levels in HGSCs. These modulators represent novel targets to enhance immunotherapy in patients with HGSCs.

Identification of three molecular subtypes based on immune infiltration in ovarian cancer and its prognostic value

BACKGROUND

Increasing studies suggest that tumor immune infiltration is a relative factor of prognosis in ovarian cancer (OvCa). The present study explored the composition of tumor-infiltrating immune cells (TIICs) in OvCa using CIBERSORT algorithm and further assessed their values for prognosis and therapeutic strategies by molecular subtypes.

METHODS

Publicly available databases including The Cancer Genome Atlas (TCGA) and GTEx were searched. Ovarian tumor samples were available from TCGA, and normal ovarian samples were obtained from the GTEx dataset. The relative proportions of immune cell profiling in OvCa and normal samples were evaluated by CIBERSORT algorithm. Association between each immune cell subtype and survival was inferred by the fractions of 22 immune cell types. "CancerSubtypes" R-package was employed to identify the three types of molecular classification and analyze the functional enrichment in each subclass. Response to immunotherapy and anticancer drug targets was predicted via TIDE algorithm and GDSC dataset.

RESULTS

Substantial variation reflecting individual difference was identified between cancer and normal tissues in the immune infiltration profiles. T cells CD4 memory activated, macrophages M1 were associated with improved overall survival (OS) as evaluated by univariate Cox regression and multivariate Cox. Three subtypes were identified by ´CancerSubtypes' R-package and every sub-cluster possessed specific immune cell characterization. Meanwhile, Cluster II exhibited poor prognosis and sensitive response to immunotherapy.

CONCLUSIONS

The cellular component of immune infiltration shows remarkable variation in OvCa. Profiling of immune infiltration is useful in prediction of prognosis of OvCa. The results from profiling might be considered in therapeutic modulation.

CD276 suppresses CAR-T cell function by promoting tumor cell glycolysis in esophageal squamous cell carcinoma

Background

As an immune checkpoint that suppresses antitumor immunity, CD276 is a potential therapeutic target for cancer immunotherapy. However, the role of CD276 in esophageal squamous cell carcinoma (ESCC) has not been thoroughly examined. A greater understanding of the regulatory mechanism of CD276 may improve the clinical response and efficacy of cancer immunotherapy.

Methods

The expression of CD276 was measured by qRT-PCR, IHC and flow cytometry analysis. T cell infiltration in ESCC was measured by qRT-PCR and immunofluorescence analysis. The regulation function of CD276 in glucose metabolism was examined by metabolism assays, western blotting and small molecule inhibitors. Transfection was used for gene editing. The oncogenic function of CD276 was examined in vivo by CAR-T cell therapy model.

Results

Based on our findings, CD276 regulated the expression of the PKM2 gene in ESCC. Overexpression of CD276 induced the phosphorylation of PKM2 by the STAT3 signalling pathway to promote glucose metabolism in tumors. The accumulation of lactic acid in the tumor microenvironment has been reported to regulate the immune cells, particularly CD8+ T cells. We further analyzed the effect of CD276 on the function of T cells. Chimeric antigen receptor T cells (CAR-T) targeting human epidermal growth factor receptor 2 (HER2) were used as effector cells to detect the effect of CD276 on immunotherapy. The therapeutic effects of CAR-T cells were markedly limited by CD276 overexpression.

Conclusions

Our results are the first to show that tumor-derived CD276 supports disease progression. Overexpression of CD276 promoted glucose metabolism in tumor and inhibited the function of CD8+ T cells. Therefore, strategies targeting CD276 might improve the response to cancer immunotherapy of ESCC patients.

Cancer-associated fibroblasts and their influence on tumor immunity and immunotherapy

Fibroblasts play an essential role in organogenesis and the integrity of tissue architecture and function. Growth in most solid tumors is dependent upon remodeling 'stroma', composed of cancer-associated fibroblasts (CAFs) and extracellular matrix (ECM), which plays a critical role in tumor initiation, progression, metastasis, and therapeutic resistance. Recent studies have clearly established that the potent immunosuppressive activity of stroma is a major mechanism by which stroma can promote tumor progression and confer resistance to immune-based therapies. Herein, we review recent advances in identifying the stroma-dependent mechanisms that regulate cancer-associated inflammation and antitumor immunity, in particular, the interactions between fibroblasts and immune cells. We also review the potential mechanisms by which stroma can confer resistance to immune-based therapies for solid tumors and current advancements in stroma-targeted therapies.

Tumor Microenvironment in Ovarian Cancer: Function and Therapeutic Strategy

Ovarian cancer is one of the leading causes of death in patients with gynecological malignancy. Despite optimal cytoreductive surgery and platinum-based chemotherapy, ovarian cancer disseminates and relapses frequently, with poor prognosis. Hence, it is urgent to find new targeted therapies for ovarian cancer. Recently, the tumor microenvironment has been reported to play a vital role in the tumorigenesis of ovarian cancer, especially with discoveries from genome-, transcriptome- and proteome-wide studies; thus tumor microenvironment may present potential therapeutic target for ovarian cancer. Here, we review the interactions between the tumor microenvironment and ovarian cancer and various therapies targeting the tumor environment.