Cold Tumors: A Therapeutic Challenge for Immunotherapy

Opposite and dynamic regulation of the interferon response in metastatic and non-metastatic breast cancer

BACKGROUND

To our current understanding, solid tumors depend on suppressed local immune reactions, often elicited by the interaction between tumor cells and tumor microenvironment (TME) components. Despite an improved understanding of anti-cancer immune responses in the TME, it is still unclear how immuno-suppressive TME are formed and how some cancer cells survive and metastasize.

METHODS

To identify the major adaptations that cancer cells undergo during tumor development and progression, we compared the transcriptome and proteome from metastatic 66cl4 and non-metastatic 67NR cell lines in culture versus their corresponding mouse mammary primary tumors. Using confocal microscopy, RT-qPCR, flow cytometry and western blotting, we studied the signaling pathway and the mechanisms involved. In addition, we used public gene expression data from human breast cancer biopsies to evaluate the correlation between gene expression and clinical outcomes in patients.

RESULTS

We found that type I interferon (IFN-I) response was a key differentially regulated pathway between metastatic and non-metastatic cell lines and tumors. The IFN-I response was active in metastatic cancer cells in culture and markedly dampened when these cells formed primary tumors. Interestingly, the opposite was observed in non-metastatic cancer cells and tumors. Consistent with an active IFN-I response in culture, the metastatic cancer cells displayed elevated levels of cytosolic DNA from both mitochondria and ruptured micronuclei with concomitant activation of cGAS-STING signaling. Interestingly, decreased IFN-I-related gene expression in breast cancer biopsies correlated with an unfavourable prognosis in patients.

CONCLUSION

Our findings show that IFN-I response is dampened in the tumors with the metastatic ability and lower IFN-I expression predicts poor prognosis in triple-negative and HER2 enriched breast cancer patients. This study highlights the possibility of reactivating the IFN-I response as a potential therapeutic strategy in breast cancer. Video Abstract.

Sorafenib increases cytochrome P450 lipid metabolites in patient with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a leading cause of cancer death, and medical treatment options are limited. The multikinase inhibitor sorafenib was the first approved drug widely used for systemic therapy in advanced HCC. Sorafenib might affect polyunsaturated fatty acids (PUFA)-derived epoxygenated metabolite levels, as it is also a potent inhibitor of the soluble epoxide hydrolase (sEH), which catalyzes the conversion of cytochrome-P450 (CYP)-derived epoxide metabolites derived from PUFA, such as omega-6 arachidonic acid (AA) and omega-3 docosahexaenoic acid (DHA), into their corresponding dihydroxy metabolites. Experimental studies with AA-derived epoxyeicosatrienoic acids (EETs) have shown that they can promote tumor growth and metastasis, while DHA-derived 19,20-epoxydocosapentaenoic acid (19,20-EDP) was shown to have anti-tumor activity in mice. In this study, we found a significant increase in EET levels in 43 HCC patients treated with sorafenib and a trend towards increased levels of DHA-derived 19,20-EDP. We demonstrate that the effect of sorafenib on CYP- metabolites led to an increase of 19,20-EDP and its dihydroxy metabolite, whereas DHA plasma levels decreased under sorafenib treatment. These data indicate that specific supplementation with DHA could be used to increase levels of the epoxy compound 19,20-EDP with potential anti-tumor activity in HCC patients receiving sorafenib therapy.

The implication of anti-PD-1 therapy in cancer patients for the vaccination against viral and other infectious diseases

The phenomenon of 'T cell exhaustion', a state of T cell dysfunction observed during chronic infections and cancers, has been a major obstacle in mounting appropriate immune responses against infectious agents or tumor antigens. The exhausted T cells are characterized by poor effector functions mainly due to the overexpression of inhibitory receptors such as programmed cell death protein 1 (PD-1), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), T cell immunoglobulin and mucin-domain containing 3 (TIM3), lymphocyte activation gene 3 (LAG3), and T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT), commonly referred to as immune checkpoint (ICP) molecules. ICP blockade, especially of PD-1 that can potentially reverse T cell exhaustion and thereby re-stimulate the impaired immune system, is widely used in clinics as a promising therapeutic strategy for various cancers and is more recently being investigated in infectious diseases as well. In fact, cancer patients represent a population of immunocompromised individuals who are more susceptible to infections and associated complications, and thus the need for protective vaccinations against these diseases is of prime importance in this category. When it comes to vaccinating anti-PD-1-treated cancer patients against infectious diseases including COVID-19 and influenza, a special focus should be brought on the revived immune cells, which could be dynamically affected by the antigenic stimulation. However, since cancer patients are not generally included in clinical trials for designing vaccines against infectious diseases, the possible interaction between vaccine immune responses and ICP therapy is largely unexplored. Mechanistically, the reversal of T cell exhaustion by ICP in an otherwise immunocompromised population could be beneficial for the vaccine's efficacy, helping the immune system to mount a robust immune response. Nevertheless, patients with cancer undergoing anti-PD-1 blockade are known to experience immune-related adverse effects (irAEs). The risk of increasing the irAEs due to the overstimulation of the immune system during vaccination is a major concern. Therefore, while routine vaccination is indispensable for the protection of cancer patients, the impact of PD-1 blockade on vaccine responses against infectious agents requires careful consideration to avoid undesirable adverse effects that could impair the efficacy of anti-cancer treatment.

Current State of Cold Atmospheric Plasma and Cancer-Immunity Cycle: Therapeutic Relevance and Overcoming Clinical Limitations Using Hydrogels

Cold atmospheric plasma (CAP) is a partially ionized gas that gains attention as a well-tolerated cancer treatment that can enhance anti-tumor immune responses, which are important for durable therapeutic effects. This review offers a comprehensive and critical summary on the current understanding of mechanisms in which CAP can assist anti-tumor immunity: induction of immunogenic cell death, oxidative post-translational modifications of the tumor and its microenvironment, epigenetic regulation of aberrant gene expression, and enhancement of immune cell functions. This should provide a rationale for the effective and meaningful clinical implementation of CAP. As discussed here, despite its potential, CAP faces different clinical limitations associated with the current CAP treatment modalities: direct exposure of cancerous cells to plasma, and indirect treatment through injection of plasma-treated liquids in the tumor. To this end, a novel modality is proposed: plasma-treated hydrogels (PTHs) that can not only help overcome some of the clinical limitations but also offer a convenient platform for combining CAP with existing drugs to improve therapeutic responses and contribute to the clinical translation of CAP. Finally, by integrating expertise in biomaterials and plasma medicine, practical considerations and prospective for the development of PTHs are offered.

Response of Locally Advanced Pancreatic Cancer to Intratumoral Injection of Large Surface Area Microparticle Paclitaxel: Initial Report of Safety and Clinical Outcome

OBJECTIVES

Large surface area microparticle paclitaxel (LSAM-PTX) provides an intratumoral (IT) chemotherapeutic depot. Safety, tolerability, and tumor response to IT LSAM-PTX delivered by endoscopic ultrasound-fine needle injection were evaluated in subjects with unresectable locally advanced pancreatic cancer (LAPC).

METHODS

Ten subjects treated in a dose escalation phase and 22 additional subjects receiving 2 injections, 4 weeks apart, of 15 mg/mL LSAM-PTX were followed for 12 months. Paclitaxel pharmacokinetics were evaluated, imaging at 3 and 6 months determined tumor response, and multiplex immunofluorescence was conducted to characterize local immune response.

RESULTS

Most treatment-emergent adverse events were attributed to LAPC. Plasma paclitaxel levels were negligible. Eight subjects' tumors became resectable after IT LSAM-PTX, and 5 of 6 (83%) were resected with R0. Multiplex immunofluorescence of resected tumors demonstrated increased T cells, natural killer cells, and macrophages and decreased myeloid-derived suppressor cells. Six-month disease control rate was 94%, and median overall survival was 19.7 months in the 2-injection subjects. For nonresected and resected groups, overall survival times were 18.9 and 35.2 months, respectively.

CONCLUSIONS

Neoadjuvant IT LSAM-PTX, in combination with SOC, was well tolerated and may provide benefits to LAPC patients, evidenced by enhanced immune response, improved disease control rate, restaging leading to surgery, and extended survival.

An angiogenesis-related three-long non-coding ribonucleic acid signature predicts the immune landscape and prognosis in hepatocellular carcinoma

The tumour microenvironment is a key determinant of the efficacy of immunotherapy. Angiogenesis is closely linked to tumour immunity. We aimed to screen long non-coding ribonucleic acids (lncRNAs) associated with angiogenesis to predict the prognosis of individuals with hepatocellular carcinoma (HCC) and characterise the tumour immune microenvironment (TIME). Patient data, including transcriptome and clinicopathological parameters, were retrieved from The Cancer Genome Atlas database. Moreover, co-expression algorithm was utilized to obtain angiogenesis-related lncRNAs. Additionally, survival-related lncRNAs were identified using Cox regression and the least absolute shrinkage and selection operator algorithm, which aided in constructing an angiogenesis-related lncRNA signature (ARLs). The ARLs was validated using Kaplan-Meier method, time-dependent receiver operating characteristic analyses, and Cox regression. Additionally, an independent external HCC dataset was used for further validation. Then, gene set enrichment analysis, immune landscape, and drug sensitivity analyses were implemented to explore the role of the ARLs. Finally, cluster analysis divided the entire HCC dataset into two clusters to distinguish different subtypes of TIME. This study provides insight into the involvement of angiogenesis-associated lncRNAs in predicting the TIME characteristics and prognosis for individuals with HCC. Furthermore, the developed ARLs and clusters can predict the prognosis and TIME characteristics in HCC, thereby aiding in selecting the appropriate therapeutic strategies involving immune checkpoint inhibitors and targeted drugs.

USP14-mediated deubiquitination of SIRT1 in macrophage promotes fatty acid oxidation amplification and M2 phenotype polarization

There is a trend of increasing young cases with gastric cancer globally. Sensitive early diagnosis methods and new therapeutic approaches are still the focus of clinical diagnosis and therapy of gastric cancer. USP14 plays an extensive role in tumor malignancy and fat metabolism regulation. However, researchers still have gaps in their knowledge of its substrates, which makes it difficult for deubiquitinases to become clinical targets. TAMs were isolated from tumor or polarized from primary THP1 cells by tumors cell lines under the control of IU1 and FAO inhibitor therapy. Cytokines controlled macrophages were compared to evaluate the capability to induce USP14 expression. Fatty acid uptake assay and OCR measurement were used to analyze macrophage metabolism. USP14 is found the correlation with tumor poor prognosis and poor immunophenotype in gastric cancer patients and mouse tumor models. Activation of USP14 determines elevated protein stability of SIRT1 and is required for activation of macrophage fatty acid oxidation and immunosuppressive phenotype. Although overexpression of USP14 is not sufficient to polarize macrophages to the M2 phenotype, inhibition of USP14 by IU1 in tumor-bearing mice disrupts the suppressive activity of cancer-promoting macrophages and effectively reshapes immune microenvironment characteristics. Our study provides evidence that a novel therapeutic strategy that targets to lipid metabolism of macrophages in tumors could be a potential option for emerging treatments for gastric cancer.

Design of a Tumor Binding GMCSF as Intratumoral Immunotherapy of Solid Tumors

Next-generation cancer immunotherapies may utilize immunostimulants to selectively activate the host immune system against tumor cells. Checkpoint inhibitors (CPIs) like anti-PD1/PDL-1 that inhibit immunosuppression have shown unprecedented success but are only effective in the 20-30% of patients that possess an already "hot" (immunogenic) tumor. In this regard, intratumoral (IT) injection of immunostimulants is a promising approach since they can work synergistically with CPIs to overcome the resistance to immunotherapies by inducing immune stimulation in the tumor. One such immunostimulant is granulocyte macrophage-colony-stimulating factor (GMCSF) that functions by recruiting and activating antigen-presenting cells (dendritic cells) in the tumor, thereby initiating anti-tumor immune responses. However, key problems with GMCSF are lack of efficacy and the risk of systemic toxicity caused by the leakage of GMCSF from the tumor tissue. We have designed tumor-retentive versions of GMCSF that are safe yet potent immunostimulants for the local treatment of solid tumors. The engineered GMCSFs (eGMCSF) were synthesized by recombinantly fusing tumor-ECM (extracellular matrix) binding peptides to GMCSF. The eGMCSFs exhibited enhanced tumor binding and potent immunological activity in vitro and in vivo. Upon IT administration, the tumor-retentive eGMCSFs persisted in the tumor, thereby alleviating systemic toxicity, and elicited localized immune activation to effectively turn an unresponsive immunologically "cold" tumor "hot".

Bispecific T-Cell Engagers Therapies in Solid Tumors: Focusing on Prostate Cancer

Over the past decade, immunotherapy has demonstrated an impressive improvement in treatment outcomes for multiple cancers. Following the landmark approvals for use of immune checkpoint inhibitors, new challenges emerged in various clinical settings. Not all tumor types harbor immunogenic characteristics capable of triggering responses. Similarly, many tumors' immune microenvironment allows them to become evasive, leading to resistance and, thus, limiting the durability of responses. To overcome this limitation, new T-cell redirecting strategies such as bispecific T-cell engager (BiTE) have become attractive and promising immunotherapies. Our review provides a comprehensive perspective of the current evidence of BiTE therapies in solid tumors. Considering that immunotherapy has shown modest results in advanced prostate cancer to date, we review the biologic rationale and promising results of BiTE therapy in this clinical setting and discuss potential tumor-associated antigens that may be integrated into BiTE construct designs. Our review also aims to evaluate the advances of BiTE therapies in prostate cancer, illustrate the major obstacles and underlying limitations, and discuss directions for future research.

Enhanced Therapeutic Efficacy of Immunostimulatory CpG-ODN by Silencing SOCS-1 with Polysaccharide/miR-155 Complexes

For the induction of antigen-specific immune responses, adjuvants as well as antigens are essential. CpG-ODN is a potent agonist of toll-like receptor 9 (TLR9) and is known as an adjuvant to induce cellular immune responses. We previously developed a therapeutic oligonucleotide delivery system based on the formation of a complex between schizophyllan (SPG), a kind of β-1,3-glucan, and poly(dA), which actively delivered CpG-ODN to antigen-presenting cells (APCs) in the draining lymph nodes and induced antigen-specific immune responses. However, unfortunately, the signaling pathway of TLR9 is negatively regulated by an intracellular protein called suppressor of cytokine signaling-1 (SOCS-1), which suppresses the adjuvant effect of CpG-ODN. To solve this, we focused on microRNA-155 (miR-155), which regulates innate and autoimmune processes by targeting SOCS-1. In this study, we proposed a strategy of combining miR-155 and CpG-ODN, each complexed with SPG (denoted as SPG/miR-155 and SPG/CpG, respectively), to induce a more potent immune response. As a result, we showed that the efficient delivery of miR-155 to APCs by a complex form could induce much more potent cellular immune responses than SPG/CpG alone. Furthermore, the mice treated with the combination of SPG/miR-155 and SPG/CpG showed a long delay in tumor growth occurrence and improved survival after tumor inoculation. These results indicate the possibility of therapeutic strategies for cancer.

Systems Biology Approaches for the Improvement of Oncolytic Virus-Based Immunotherapies

Oncolytic virus (OV)-based immunotherapy is mainly dependent on establishing an efficient cell-mediated antitumor immunity. OV-mediated antitumor immunity elicits a renewed antitumor reactivity, stimulating a T-cell response against tumor-associated antigens (TAAs) and recruiting natural killer cells within the tumor microenvironment (TME). Despite the fact that OVs are unspecific cancer vaccine platforms, to further enhance antitumor immunity, it is crucial to identify the potentially immunogenic T-cell restricted TAAs, the main key orchestrators in evoking a specific and durable cytotoxic T-cell response. Today, innovative approaches derived from systems biology are exploited to improve target discovery in several types of cancer and to identify the MHC-I and II restricted peptide repertoire recognized by T-cells. Using specific computation pipelines, it is possible to select the best tumor peptide candidates that can be efficiently vectorized and delivered by numerous OV-based platforms, in order to reinforce anticancer immune responses. Beyond the identification of TAAs, system biology can also support the engineering of OVs with improved oncotropism to reduce toxicity and maintain a sufficient portion of the wild-type virus virulence. Finally, these technologies can also pave the way towards a more rational design of armed OVs where a transgene of interest can be delivered to TME to develop an intratumoral gene therapy to enhance specific immune stimuli.

Immunotherapy for Metastatic Non-Small Cell Lung Cancer: Therapeutic Advances and Biomarkers

Immunotherapy has revolutionized the treatment paradigm of non-small cell lung cancer and improved patients' prognosis. Immune checkpoint inhibitors have quickly become standard frontline treatment for metastatic non-oncogene addicted disease, either as a single agent or in combination strategies. However, only a few patients have long-term benefits, and most of them do not respond or develop progressive disease during treatment. Thus, the identification of reliable predictive and prognostic biomarkers remains crucial for patient selection and guiding therapeutic choices. In this review, we provide an overview of the current strategies, highlighting the main clinical challenges and novel potential biomarkers.

Challenges to addressing the unmet medical needs for immunotherapy targeting cold colorectal cancer

With the establishment of the immune surveillance mechanism since the 1950s, attempts have been made to activate the immune system for cancer treatment through the discovery of various cytokines or the development of antibodies up to now. The fruits of these efforts have contributed to the recognition of the 3^rd generation of anticancer immunotherapy as the mainstream of cancer treatment. However, the limitations of cancer immunotherapy are also being recognized through the conceptual establishment of cold tumors recently, and colorectal cancer (CRC) has become a major issue from this therapeutic point of view. Here, it is emphasized that non-clinical strategies to overcome the immunosuppressive environment and clinical trials based on these basic investigations are being made on the journey to achieve better treatment outcomes for the treatment of cold CRC.

Neutrophil-activating therapy for the treatment of cancer

Despite their cytotoxic capacity, neutrophils are often co-opted by cancers to promote immunosuppression, tumor growth, and metastasis. Consequently, these cells have received little attention as potential cancer immunotherapeutic agents. Here, we demonstrate in mouse models that neutrophils can be harnessed to induce eradication of tumors and reduce metastatic seeding through the combined actions of tumor necrosis factor, CD40 agonist, and tumor-binding antibody. The same combination activates human neutrophils in vitro, enabling their lysis of human tumor cells. Mechanistically, this therapy induces rapid mobilization and tumor infiltration of neutrophils along with complement activation in tumors. Complement component C5a activates neutrophils to produce leukotriene B4, which stimulates reactive oxygen species production via xanthine oxidase, resulting in oxidative damage and T cell-independent clearance of multiple tumor types. These data establish neutrophils as potent anti-tumor immune mediators and define an inflammatory pathway that can be harnessed to drive neutrophil-mediated eradication of cancer.

Constructing 3D In Vitro Models of Heterocellular Solid Tumors and Stromal Tissues Using Extrusion-Based Bioprinting

Malignant tumor tissues exhibit inter- and intratumoral heterogeneities, aberrant development, dynamic stromal composition, diverse tissue phenotypes, and cell populations growing within localized mechanical stresses in hypoxic conditions. Experimental tumor models employing engineered systems that isolate and study these complex variables using in vitro techniques are under development as complementary methods to preclinical in vivo models. Here, advances in extrusion bioprinting as an enabling technology to recreate the three-dimensional tumor milieu and its complex heterogeneous characteristics are reviewed. Extrusion bioprinting allows for the deposition of multiple materials, or selected cell types and concentrations, into models based upon physiological features of the tumor. This affords the creation of complex samples with representative extracellular or stromal compositions that replicate the biology of patient tissue. Biomaterial engineering of printable materials that replicate specific features of the tumor microenvironment offer experimental reproducibility, throughput, and physiological relevance compared to animal models. In this review, we describe the potential of extrusion-based bioprinting to recreate the tumor microenvironment within in vitro models.

PLGA Particles in Immunotherapy

Poly(lactic-co-glycolic acid) (PLGA) particles are a widely used and extensively studied drug delivery system. The favorable properties of PLGA such as good bioavailability, controlled release, and an excellent safety profile due to the biodegradable polymer backbone qualified PLGA particles for approval by the authorities for the application as a drug delivery platform in humas. In recent years, immunotherapy has been established as a potent treatment option for a variety of diseases. However, immunomodulating drugs rely on targeted delivery to specific immune cell subsets and are often rapidly eliminated from the system. Loading of PLGA particles with drugs for immunotherapy can protect the therapeutic compounds from premature degradation, direct the drug delivery to specific tissues or cells, and ensure sustained and controlled drug release. These properties present PLGA particles as an ideal platform for immunotherapy. Here, we review recent advances of particulate PLGA delivery systems in the application for immunotherapy in the fields of allergy, autoimmunity, infectious diseases, and cancer.

LRP2 and DOCK8 Are Potential Antigens for mRNA Vaccine Development in Immunologically 'Cold' KIRC Tumours

The administration of mRNA-based tumour vaccines is considered a promising strategy in tumour immunotherapy, although its application against kidney renal clear cell carcinoma (KIRC) is still at its infancy stage. The purpose of this study was to identify potential antigens and to further select suitable patients for vaccination. Gene expression data and clinical information were retrieved from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. GEPIA2 was used to evaluate the prognostic value of selected antigens. The relationship of antigens presenting cell infiltration with antigen expression was evaluated by TIMER, and immune subtypes were determined using unsupervised cluster analysis. Tumour antigens LRP2 and DOCK8, which are associated with prognosis and tumour-infiltrating antigen-presenting cells, were identified in KIRC. A total of six immune subtypes were identified, and patients with immune subtype 1-4 (IS1-4) tumours had an immune 'cold' phenotype, a higher tumour mutation burden, and poor survival. Moreover, these immune subtypes showed significant differences in the expression of immune checkpoint and immunogenic cell death modulators. Finally, the immune landscape of KIRC revealed the immune-related cell components in individual patients. This study suggests that LRP2 and DOCK8 are potential KIRC antigens in the development of mRNA vaccines, and patients with immune subtypes IS1-4 are suitable for vaccination.

Thermal immuno-nanomedicine in cancer

Immunotherapy has revolutionized the treatment of patients with cancer. However, promoting antitumour immunity in patients with tumours that are resistant to these therapies remains a challenge. Thermal therapies provide a promising immune-adjuvant strategy for use with immunotherapy, mostly owing to the capacity to reprogramme the tumour microenvironment through induction of immunogenic cell death, which also promotes the recruitment of endogenous immune cells. Thus, thermal immunotherapeutic strategies for various cancers are an area of considerable research interest. In this Review, we describe the role of the various thermal therapies and provide an update on attempts to combine these with immunotherapies in clinical trials. We also provide an overview of the preclinical development of various thermal immuno-nanomedicines, which are capable of combining thermal therapies with various immunotherapy strategies in a single therapeutic platform. Finally, we discuss the challenges associated with the clinical translation of thermal immuno-nanomedicines and emphasize the importance of multidisciplinary and inter-professional collaboration to facilitate the optimal translation of this technology from bench to bedside.

Metabolic Challenges in Anticancer CD8 T Cell Functions

Cancer immunotherapies continue to face numerous obstacles in the successful treatment of solid malignancies. While immunotherapy has emerged as an extremely effective treatment option for hematologic malignancies, it is largely ineffective against solid tumors due in part to metabolic challenges present in the tumor microenvironment (TME). Tumor-infiltrating CD8⁺ T cells face fierce competition with cancer cells for limited nutrients. The strong metabolic suppression in the TME often leads to impaired T-cell recruitment to the tumor site and hyporesponsive effector functions via T-cell exhaustion. Growing evidence suggests that mitochondria play a key role in CD8⁺ T-cell activation, migration, effector functions, and persistence in tumors. Therefore, targeting the mitochondrial metabolism of adoptively transferred T cells has the potential to greatly improve the effectiveness of cancer immunotherapies in treating solid malignancies.

MTAP deficiency contributes to immune landscape remodelling and tumour evasion

Methylthioadenosine phosphorylase (MTAP) deficiency occurs in various malignancies and is associated with poor survival in cancer patients. However, the mechanisms underlying tumour progression due to MTAP loss are yet to be elucidated. Utilizing integrated analyses of the transcriptome, proteome and secretome, we demonstrated that MTAP deficiency alters tumour-intrinsic, immune-related pathways and reprograms cytokine profiles towards a tumour-favourable environment. Additionally, MTAP-knockout cells exhibited a marked increase in the immune checkpoint protein PD-L1. Upon co-culturing primary T cells with cancer cells, MTAP loss-mediated PD-L1 upregulation inhibited T cell-mediated killing activity and induced several T cell exhaustion markers. In two xenograft tumour models, we showed a modest increase in average volume of tumours derived from MTAP-deficient cells than that of MTAP-proficient tumours. Surprisingly, a remarkable increase in tumour size was observed in humanized mice bearing MTAP-deficient tumours, as compared to their MTAP-expressing counterparts. Following immunophenotypic characterization of tumour-infiltrating leukocytes by mass cytometry analysis, MTAP-deficient tumours were found to display decreased immune infiltrates with lower proportions of both T lymphocytes and natural killer cells and higher proportions of immunosuppressive cells as compared to MTAP-expressing tumour xenografts. Taken together, our results suggest that MTAP deficiency restructures the tumour immune microenvironment, promoting tumour progression and immune evasion.

Leading Edge: Intratumor Delivery of Monoclonal Antibodies for the Treatment of Solid Tumors

Immunotherapies based on immune checkpoint blockade have shown remarkable clinical outcomes and durable responses in patients with many tumor types. Nevertheless, these therapies lack efficacy in most cancer patients, even causing severe adverse events in a small subset of patients, such as inflammatory disorders and hyper-progressive disease. To diminish the risk of developing serious toxicities, intratumor delivery of monoclonal antibodies could be a solution. Encouraging results have been shown in both preclinical and clinical studies. Thus, intratumor immunotherapy as a new strategy may retain efficacy while increasing safety. This approach is still an exploratory frontier in cancer research and opens up new possibilities for next-generation personalized medicine. Local intratumor delivery can be achieved through many means, but an attractive approach is the use of gene therapy vectors expressing mAbs inside the tumor mass. Here, we summarize basic, translational, and clinical results of intratumor mAb delivery, together with descriptions of non-viral and viral strategies for mAb delivery in preclinical and clinical development. Currently, this is an expanding research subject that will surely play a key role in the future of oncology.

Novel Local "Off-the-Shelf" Immunotherapy for the Treatment of Myeloma Bone Disease

Myeloma bone disease (MBD) is one of the major complications in multiple myeloma (MM)-the second most frequent hematologic malignancy. It is characterized by the formation of bone lesions due to the local action of proliferating MM cells, and to date, no effective therapy has been developed. In this study, we propose a novel approach for the local treatment of MBD with a combination of natural killer cells (NKs) and mesenchymal stem cells (MSCs) within a fibrin scaffold, altogether known as FINM. The unique biological properties of the NKs and MSCs, joined to the injectable biocompatible fibrin, permitted to obtain an efficient "off-the-shelf" ready-to-use composite for the local treatment of MBD. Our in vitro analyses demonstrate that NKs within FINM exert a robust anti-tumor activity against MM cell lines and primary cells, with the capacity to suppress osteoclast activity (~60%) within in vitro 3D model of MBD. Furthermore, NKs' post-thawing cytotoxic activity is significantly enhanced (~75%) in the presence of MSCs, which circumvents the decrease of NKs cytotoxicity after thawing, a well-known issue in the cryopreservation of NKs. To reduce the tumor escape, we combined FINM with other therapeutic agents (bortezomib (BZ), and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)), observing a clear therapeutic synergistic effect in vitro. Finally, the therapeutic efficacy of FINM in combination with BZ and TRAIL was assessed in a mouse model of MM, achieving 16-fold smaller tumors compared to the control group without treatment. These results suggest the potential of FINM to serve as an allogeneic "off-the-shelf" approach to improve the outcomes of patients suffering from MBD.

TYRO3 blockade enhances anti-PD-1 therapy response by modulating expression of CCN1 in tumor microenvironment

BACKGROUND

Immunological contexture differs across malignancies, and understanding it in the tumor microenvironment (TME) is essential for development of new anticancer agents in order to achieve synergistic effects with anti-programmed cell death protein-1 (PD-1) therapy. TYRO3, AXL, and MERTK receptors are bi-expressed in both cancer and immune cells, and thus emerge as promising targets for therapeutic intervention. Whereas AXL and MERTK have been extensively studied, the role of TYRO3, in the TME, is still undetermined.

METHODS

Here, we screened the TYRO3-focused chemical library consisting of 208 compounds and presented a potent and highly selective TYRO3 inhibitor, KRCT87. We explored the role of TYRO3 using mouse engrafting MC38 or 4T1 tumors. We validated the results using flow cytometry, RNA sequencing analysis, gene knockdown or overexpression, ex vivo immune cells isolation from mouse models, immunoblotting and quantitative PCR. Flow cytometry was used for the quantification of cell populations and immunophenotyping of macrophages and T cells. Co-cultures of macrophages and T cells were performed to verify the role of CCN1 in the tumors.

RESULTS

TYRO3 blockade boosts antitumor immune responses in both the tumor-draining lymph nodes and tumors in MC38-syngeneic mice models. Moreover, the combination of KRCT87 and anti-PD-1 therapy exerts significant synergistic antitumor effects in anti-PD-1-non-responsive 4T1-syngeneic model. Mechanistically, we demonstrated that inhibition of TYRO3-driven CCN1 secretion fosters macrophages into M1-skewing phenotypes, thereby triggering antitumor T-cell responses. CCN1 overexpression in MC38 tumors diminishes responsiveness to anti-PD-1 therapy.

CONCLUSIONS

The activated TYRO3-CCN1 axis in cancer could dampen anti-PD-1 therapy responses. These findings highlight the potential of TYRO3 blockade to improve the clinical outcomes of anti-PD-1 therapy.

Proteomic and single-cell landscape reveals novel pathogenic mechanisms of HBV-infected intrahepatic cholangiocarcinoma

Despite the epidemiological association between intrahepatic cholangiocarcinoma (ICC) and hepatitis B virus (HBV) infection, little is known about the relevant oncogenic effects. A cohort of 32 HBV-infected ICC and 89 non-HBV-ICC patients were characterized using whole-exome sequencing, proteomic analysis, and single-cell RNA sequencing. Proteomic analysis revealed decreased cell-cell junction levels in HBV-ICC patients. The cell-cell junction level had an inverse relationship with the epithelial-mesenchymal transition (EMT) program in ICC patients. Analysis of the immune landscape found that more CD8 T cells and Th2 cells were present in HBV-ICC patients. Single-cell analysis indicated that transforming growth factor beta signaling-related EMT program changes increased in tumor cells of HBV-ICC patients. Moreover, ICAM1⁺ tumor-associated macrophages are correlated with a poor prognosis and contributed to the EMT in HBV-ICC patients. Our findings provide new insights into the behavior of HBV-infected ICC driven by various pathogenic mechanisms involving decreased cell junction levels and increased progression of the EMT program.

Definition and Characterization of SOX11-Derived T Cell Epitopes towards Immunotherapy of Glioma

The transcription factor SOX11 is a tumor-associated antigen with low expression in normal cells, but overexpression in glioblastoma (GBM). So far, conventional surgery, chemotherapy, and radiotherapy have not substantially improved the dismal prognosis of relapsed/refractory GBM patients. Immunotherapy is considered a promising strategy against GBM, but there is a fervent need for better immunotargets in GBM. To this end, we performed an in silico prediction study on SOX11, which primarily yielded ten promising HLA-A*0201-restricted peptides derived from SOX11. We defined a novel peptide FMACSPVAL, which had the highest score according to in silico prediction (6.02 nM by NetMHC-4.0) and showed an exquisite binding affinity to the HLA-A*0201 molecule in the peptide-binding assays. In the IFN-γ ELISPOT assays, FMACSPVAL demonstrated a high efficiency for generating SOX11-specific CD8⁺ T cells. Nine out of thirty-two healthy donors showed a positive response to SOX11, as assessed by the ELISPOT assays. Therefore, this novel antigen peptide epitope seems to be promising as a target for T cell-based immunotherapy in GBM. The adoptive transfer of in vitro elicited SOX11-specific CD8⁺ T cells constitutes a potential approach for the treatment of GBM patients.

Novel combination strategy of high intensity focused ultrasound (HIFU) and checkpoint blockade boosted by bioinspired and oxygen-supplied nanoprobe for multimodal imaging-guided cancer therapy

BACKGROUND

High-intensity focused ultrasound (HIFU) has shown considerable promise in treating solid tumors, but its ultrasonic energy is easily attenuated, resulting in insufficient energy accumulation in the target area. Moreover, HIFU ablation alone may inevitably lead to the presence of residual tumors, which may cause tumor recurrence and metastasis. Here, we describe a synergistic regimen combining HIFU facilitation with immunomodulation based on a novel oxygen-carrying biomimetic perfluorocarbon nanoparticle (M@P-SOP) to stimulate immunogenic cell death in tumor cells while alleviating immune suppression tumor microenvironment.

METHODS

M@P-SOP was prepared by double emulsion and film extrusion method. The anticancer and antimetastatic effects of M@P-SOP were evaluated on a preclinical transplanted 4T1 tumor model by combining HIFU and immunotherapy. Flow cytometry and immunofluorescence were used to clarify the potential mechanism of HIFU+M@P-SOP and their role in anti-programmed death ligand-1 (PD-L1) therapy.

RESULTS

Guided by photoacoustic/MR/ultrasound (US) multimodal imaging, M@P-SOP was abundantly enriched in tumor, which greatly enhanced HIFU's killing of tumor tissue in situ, induced stronger tumor immunogenic cell death, stimulated dendritic cell maturation and activated CD8⁺ T cells. At the same time, M@P-SOP released oxygen to alleviate the tumor hypoxic environment, repolarizing the protumor M2-type macrophages into antitumor M1-type. With concurrent anti-PD-L1 treatment, the antitumor immune response was further amplified to the whole body, and the growth of mimic distant tumor was effectively suppressed.

CONCLUSIONS

Our findings offer a highly promising HIFU synergist for effectively ameliorating acoustic and hypoxia environment, eventually inhibiting tumor growth and metastasis by stimulating host's antitumor immunity under HIFU ablation, especially in synergizing with PD-L1 antibody immunotherapy.

Melanoma Cell Reprogramming and Awakening of Antitumor Immunity as a Fingerprint of Hyper-Harmonized Hydroxylated Fullerene Water Complex (3HFWC) and Hyperpolarized Light Application In Vivo

In our recent study, we showed that in vitro treatment of melanoma cells with hyperpolarized light (HPL) as well as with the second derivative of fullerene, hyper-harmonized hydroxylated fullerene water complex (3HFWC) reduced viability of cells by decreasing their proliferative capacity and inducing senescence and reprogramming towards a normal, melanocytic phenotype. Therefore, we wanted to determine whether these effects persisted in vivo in the syngeneic mouse melanoma model with a combined treatment of HPL irradiation and 3HFWC per os. Our results demonstrated the potent antitumor effects of 3HFWC nanosubstance assisted by HPL irradiation. These effects were primarily driven by the stimulation of melanoma cell growth arrest, the establishment of a senescent phenotype, and melanocytic differentiation on the one hand, and the awakening of the antitumor immune response on the other. In addition, the combined treatment reduced the protumorigenic activity of immune cells by depleting T regulatory cells, myeloid-derived suppressors, and M2 macrophages. The support of the 3HFWC substance by HPL irradiation may be the axis of the new approach design based on tumor cell reprogramming synchronized with the mobilization of the host's protective immune response.

Challenges and exploration for immunotherapies targeting cold colorectal cancer

In recent years, immune checkpoint inhibitors (ICIs) have made significant breakthroughs in the treatment of various tumors, greatly improving clinical efficacy. As the fifth most common antitumor treatment strategy for patients with solid tumors after surgery, chemotherapy, radiotherapy and targeted therapy, the therapeutic response to ICIs largely depends on the number and spatial distribution of effector T cells that can effectively identify and kill tumor cells, features that are also important when distinguishing malignant tumors from “cold tumors” or “hot tumors”. At present, only a small proportion of colorectal cancer (CRC) patients with deficient mismatch repair (dMMR) or who are microsatellite instability-high (MSI-H) can benefit from ICI treatments because these patients have the characteristics of a “hot tumor”, with a high tumor mutational burden (TMB) and massive immune cell infiltration, making the tumor more easily recognized by the immune system. In contrast, a majority of CRC patients with proficient MMR (pMMR) or who are microsatellite stable (MSS) have a low TMB, lack immune cell infiltration, and have almost no response to immune monotherapy; thus, these tumors are “cold”. The greatest challenge today is how to improve the immunotherapy response of “cold tumor” patients. With the development of clinical research, immunotherapies combined with other treatment strategies (such as targeted therapy, chemotherapy, and radiotherapy) have now become potentially effective clinical strategies and research hotspots. Therefore, the question of how to promote the transformation of “cold tumors” to “hot tumors” and break through the bottleneck of immunotherapy for cold tumors in CRC patients urgently requires consideration. Only by developing an in-depth understanding of the immunotherapy mechanisms of cold CRCs can we screen out the immunotherapy-dominant groups and explore the most suitable treatment options for individuals to improve therapeutic efficacy.

Basic and translational research on carbon-ion radiobiology

Carbon-ion beam irradiation (IR) has evident advantages over the conventional photon beams in treating tumors. It releases enormous amount of energy in a well-defined range with insignificant scatter in surrounding tissues based on well-localized energy deposition. Over the past 28 years, more than 14,000 patients with various types of cancer have been treated by carbon ion radiotherapy (CIRT) with promising results at QST. I have provided an overview of the basic and translational research on carbon-ion radiobiology including mechanisms underlying high linear energy transfer (LET) carbon-ion IR-induced cell death (apoptosis, autophagy, senescence, mitotic catastrophe etc.) and high radiocurability produced by carbon-ion beams in combination with DNA damaging drugs or with molecular-targeted drugs, micro-RNA therapeutics and immunotherapy. Additionally, I have focused on the application of these treatment in human cancer cells, especially cancer stem cells (CSCs). Finally, I have summarized the current studies on the application of basic carbon-ion beam IR according to the cancer types and clinical outcomes.

Phase Ib open-label, multicenter study of pixatimod, an activator of TLR9, in combination with nivolumab in subjects with microsatellite-stable metastatic colorectal cancer, metastatic pancreatic ductal adenocarcinoma and other solid tumors

BACKGROUND

Pixatimod is a unique activator of the Toll-like Receptor 9 pathway. This phase I trial evaluated safety, efficacy and pharmacodynamics of pixatimod and PD-1 inhibitor nivolumab in immunologically cold cancers.

METHODS

3+3 dose escalation with microsatellite stable metastatic colorectal cancer (MSS mCRC) and metastatic pancreatic ductal adenocarcinoma (mPDAC) expansion cohorts. Participants received pixatimod once weekly as a 1-hour intravenous infusion plus nivolumab every 2 weeks. Objectives included assessment of safety, antitumor activity, pharmacodynamics, and pharmacokinetic profile.

RESULTS

Fifty-eight participants started treatment. The maximum tolerated dose of pixatimod was 25 mg in combination with 240 mg nivolumab, which was used in the expansion phases of the study. Twenty-one grade 3-5 treatment-related adverse events were reported in 12 participants (21%); one participant receiving 50 mg pixatimod/nivolumab had a treatment-related grade 5 AE. The grade 3/4 rate in the MSS mCRC cohort (n=33) was 12%. There were no responders in the mPDAC cohort (n=18). In the MSS mCRC cohort, 25 participants were evaluable (initial postbaseline assessment scans >6 weeks); of these, three participants had confirmed partial responses (PR) and eight had stable disease (SD) for at least 9 weeks. Clinical benefit (PR+SD) was associated with lower Pan-Immune-Inflammation Value and plasma IL-6 but increased IP-10 and IP-10/IL-8 ratio. In an MSS mCRC participant with PR as best response, increased infiltration of T cells, dendritic cells, and to a lesser extent NK cells, were evident 5 weeks post-treatment.

CONCLUSIONS

Pixatimod is well tolerated at 25 mg in combination with nivolumab. The efficacy signal and pharmacodynamic changes in MSS mCRC warrants further investigation.

TRIAL REGISTRATION NUMBER

NCT05061017.

Targeting Epigenetic Mechanisms: A Boon for Cancer Immunotherapy

Immunotherapy is rapidly emerging as a promising approach against cancer. In the last decade, various immunological mechanisms have been targeted to induce an increase in the immune response against cancer cells. However, despite promising results, many patients show partial response, resistance, or serious toxicities. A promising way to overcome this is the use of immunotherapeutic approaches, in combination with other potential therapeutic approaches. Aberrant epigenetic modifications play an important role in carcinogenesis and its progression, as well as in the functioning of immune cells. Thus, therapeutic approaches targeting aberrant epigenetic mechanisms and the immune response might provide an effective antitumor effect. Further, the recent development of potent epigenetic drugs and immunomodulators gives hope to this combinatorial approach. In this review, we summarize the synergy mechanism between epigenetic therapies and immunotherapy for the treatment of cancer, and discuss recent advancements in the translation of this approach.

Liquid biopsy approaches and immunotherapy in colorectal cancer for precision medicine: Are we there yet?

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths globally, with nearly half of patients detected in the advanced stages. This is due to the fact that symptoms associated with CRC often do not appear until the cancer has reached an advanced stage. This suggests that CRC is a cancer with a slow progression, making it curable and preventive if detected in its early stage. Therefore, there is an urgent clinical need to improve CRC early detection and personalize therapy for patients with this cancer. Recently, liquid biopsy as a non-invasive or nominally invasive approach has attracted considerable interest for its real-time disease monitoring capability through repeated sample analysis. Several studies in CRC have revealed the potential for liquid biopsy application in a real clinical setting using circulating RNA/miRNA, circulating tumor cells (CTCs), exosomes, etc. However, Liquid biopsy still remains a challenge since there are currently no promising results with high specificity and specificity that might be employed as optimal circulatory biomarkers. Therefore, in this review, we conferred the plausible role of less explored liquid biopsy components like mitochondrial DNA (mtDNA), organoid model of CTCs, and circulating cancer-associated fibroblasts (cCAFs); which may allow researchers to develop improved strategies to unravel unfulfilled clinical requirements in CRC patients. Moreover, we have also discussed immunotherapy approaches to improve the prognosis of MSI (Microsatellite Instability) CRC patients using neoantigens and immune cells in the tumor microenvironment (TME) as a liquid biopsy approach in detail.

Proteolytic regulation of CD73 by TRIM21 orchestrates tumor immunogenicity

Despite the rapid utilization of immunotherapy, emerging challenges to the current immune checkpoint blockade need to be resolved. Here, we report that elevation of CD73 levels due to its aberrant turnover is correlated with poor prognosis in immune-cold triple-negative breast cancers (TNBCs). We have identified TRIM21 as an E3 ligase that governs CD73 destruction. Disruption of TRIM21 stabilizes CD73 that in turn enhances CD73-catalyzed production of adenosine, resulting in the suppression of CD8+ T cell function. Replacement of lysine 133, 208, 262, and 321 residues by arginine on CD73 attenuated CD73 ubiquitylation and degradation. Diminishing of CD73 ubiquitylation remarkably promotes tumor growth and impedes antitumor immunity. In addition, a TRIM21high/CD73low signature in a subgroup of human breast malignancies was associated with a favorable immune profile. Collectively, our findings uncover a mechanism that governs CD73 proteolysis and point to a new therapeutic strategy by modulating CD73 ubiquitylation.

Combination therapy with oncolytic viruses and immune checkpoint inhibitors in head and neck squamous cell carcinomas: an approach of complementary advantages

Squamous cell carcinomas are the most common head and neck malignancies. Significant progress has been made in standard therapeutic methods combining surgery, radiation, and chemotherapy. Nevertheless, the 5-year survival rate remains at 40-50%. Immune checkpoint inhibitors (ICIs) are a new strategy for treating head and neck squamous cell carcinomas (HNSCCs). Still, the overall response and effective rates are poor, as HNSCCs are 'cold' tumors with an immunosuppressive tumor microenvironment (TME), limiting ICI's beneficial effects. In this case, transforming the tumor suppression microenvironment before using ICIs could be helpful. Oncolytic viruses (OVs) can transform cold tumors into hot tumors, improving the situation. Talimogene laherparepvec (T-VEC), oncolytic immunotherapy authorized for advanced melanoma, also showed good safety and antitumor activity in treating head and neck cancer and pancreatic cancer. In combination with pembrolizumab, T-Vec may have more anticancer efficacy than either drug alone. Therefore, understanding the mechanisms underpinning OVs and their potential synergism with ICIs could benefit patients with HNSCC.

Intimate communications within the tumor microenvironment: stromal factors function as an orchestra

Extensive studies of the tumor microenvironment (TME) in the last decade have reformed the view of cancer as a tumor cell-centric disease. The tumor microenvironment, especially termed the "seed and soil" theory, has emerged as the key determinant in cancer development and therapeutic resistance. The TME mainly consists of tumor cells, stromal cells such as fibroblasts, immune cells, and other noncellular components. Within the TME, intimate communications among these components largely determine the fate of the tumor. The pivotal roles of the stroma, especially cancer-associated fibroblasts (CAFs), the most common component within the TME, have been revealed in tumorigenesis, tumor progression, therapeutic response, and tumor immunity. A better understanding of the function of the TME sheds light on tumor therapy. In this review, we summarize the emerging understanding of stromal factors, especially CAFs, in cancer progression, drug resistance, and tumor immunity with an emphasis on their functions in epigenetic regulation. Moreover, the importance of epigenetic regulation in reshaping the TME and the basic biological principles underpinning the synergy between epigenetic therapy and immunotherapy will be further discussed.

Enhancedanti-tumor efficacy through a combination of intramuscularly expressed DNA vaccine and plasmid-encoded PD-1 antibody

Immune check inhibitors (ICIs) have moderate response rates (~20%-30%) in some malignancies clinically, and, when used in combination with other immunotherapeutic strategies such as DNA tumor vaccines, there is evidence to suggest that they could optimize the efficacy of cancer treatment. In this study, we validated that intramuscular injection of plasmid DNA (pDNA) encoding OVA combined with pDNA encoding α-PD-1 (abbreviated as α-PD-1 in the following treatment groups) may enhance therapeutic efficacy by means of in situ gene delivery and enhanced muscle-specific potent promoter. Mice treated with pDNA-OVA or pDNA-α-PD-1 alone showed weak tumor inhibition in the MC38-OVA-bearing model. In comparison, the combined treatment of pDNA-OVA and pDNA-α-PD-1 resulted in superior tumor growth inhibition and a significantly improved survival rate of over 60% on day 45. In the B16-F10-OVA metastasis model, the addition of the DNA vaccine enhanced resistance to tumor metastasis and increased the populations of CD8⁺ T cells in blood and spleen. In conclusion, the current research shows that a combination of pDNA-encoded PD-1 antibody and DNA vaccine expressed in vivo is an efficient, safe, and economical strategy for tumor therapy.

Tailoring therapies to counter the divergent immune landscapes of breast cancer

Breast cancer remains a significant clinical concern affecting millions of women worldwide. Immunotherapy is a rapidly growing drug class that has revolutionized cancer treatment but remains marginally successful in breast cancer. The success of immunotherapy is dependent on the baseline immune responses as well as removing the brakes off pre-existing anti-tumor immunity. In this review, we summarize the different types of immune microenvironment observed in breast cancer as well as provide approaches to target these different immune subtypes. Such approaches have demonstrated pre-clinical success and are currently under clinical evaluation. The impact of combination of these approaches with already approved chemotherapies and immunotherapies may improve patient outcome and survival.

Mechanism of action of DSP-7888 (adegramotide/nelatimotide) Emulsion, a peptide-based therapeutic cancer vaccine with the potential to turn up the heat on non-immunoreactive tumors

BACKGROUND

Wilms' tumor 1 (WT1) is highly expressed in various solid tumors and hematologic malignancies. DSP-7888 (adegramotide/nelatimotide) Emulsion is an investigational therapeutic cancer vaccine comprising three synthetic epitopes derived from WT1. We evaluated the mechanism of action of DSP-7888 Emulsion, which is hypothesized to induce WT1-specific cytotoxic T lymphocytes (CTLs) and helper T lymphocytes (HTLs).

METHODS

The ability of nelatimotide and adegramotide to induce WT1-specific CD8⁺ T cells and CD4⁺ T cells was assessed in human peripheral blood mononuclear cells (PBMCs). The ability of DSP-7888 Emulsion to induce WT1-specific CTLs in vivo was assessed using human leukocyte antigen-I (HLA-I) transgenic mice. To assess how adegramotide, the helper peptide in DSP-7888 Emulsion, enhances WT1-specific CTLs, HLA-I transgenic mice were administered DSP-7888 or nelatimotide-only Emulsion. Interferon-gamma secretion under antigen stimulation by splenocytes co-cultured with or without tumor cells was then quantified. The effects of combination treatment with DSP-7888 Emulsion and an anti-programmed cell death protein 1 (PD-1) antibody on tumor volume and the frequency of tumor-infiltrating WT1-specific T cells were assessed in HLA-I transgenic mice implanted with WT1 antigen-positive tumors.

RESULTS

The peptides in DSP-7888 Emulsion were shown to induce WT1-specific CTLs and HTLs in both human PBMCs and HLA-I transgenic mice. Unlike splenocytes from nelatimotide-only Emulsion-treated mice, splenocytes from DSP-7888 Emulsion-treated mice exhibited high levels of interferon-gamma secretion, including when co-cultured with tumor cells; interferon-gamma secretion was further enhanced by concomitant treatment with anti-PD-1. HLA-I transgenic mice administered DSP-7888 Emulsion plus anti-PD-1 experienced significantly greater reductions in tumor size than mice treated with either agent alone. This reduction in tumor volume was accompanied by increased numbers of tumor-infiltrating WT1-specific CTLs.

CONCLUSIONS

DSP-7888 Emulsion can promote both cytotoxic and helper T-cell-mediated immune responses against WT1-positive tumors. Adegramotide enhances CTL numbers, and the CTLs induced by treatment with both nelatimotide and adegramotide are capable of functioning within the immunosuppressive tumor microenvironment. The ability of anti-PD-1 to enhance the antitumor activity of DSP-7888 Emulsion in mice implanted with WT1-positive tumors suggests the potential for synergy.

An enhancer variant associated with breast cancer susceptibility in Black women regulates TNFSF10 expression and antitumor immunity in triple-negative breast cancer

Women of African ancestry have the highest mortality from triple-negative breast cancer (TNBC) of all racial groups. To understand the genomic basis of breast cancer in the populations, we previously conducted genome-wide association studies and identified single nucleotide polymorphisms (SNPs) associated with breast cancer in Black women. In this study, we investigated the functional significance of the top associated SNP rs13074711. We found the SNP served as an enhancer variant and regulated TNFSF10 (TRAIL) expression in TNBC cells, with a significant association between the SNP genotype and TNFSF10 expression in breast tumors. Mechanistically, rs13074711 modulated the binding activity of c-MYB at the motif and thereby controlled TNFSF10 expression. Interestingly, TNFSF10 expression in many cancers was consistently lower in African Americans compared with European Americans. Furthermore, TNFSF10 expression in TNBC was significantly correlated with the expression of antiviral immune genes and was regulated by type I interferons (IFNs). Accordingly, loss of TNFSF10 resulted in a profound decrease in apoptosis of TNBC cells in response to type I IFNs and poly(I:C), a synthetic analogue of double stranded virus. Lastly, in a syngeneic mouse model of breast cancer, TNFSF10-deficiency in breast tumors decreased tumor-infiltrated CD4+ and CD8+ T cell quantities. Collectively, our results suggested that TNFSF10 plays an important role in the regulation of antiviral immune responses in TNBC, and the expression is in part regulated by a genetic variant associated with breast cancer in Black women. Our results underscore the important contributions of genetic variants to immune defense mechanisms.

Increased death and exhaustion of CD69high T cells and NK cells are associated with PD-1 antibody application in the in vitro co-culture system

Background

The application of PD-1 monoclonal antibody (mAb) helps to treat non-small cell lung cancer, but acquired resistance has emerged in clinical practice. We tested the hypothesis that acquired resistance of anti-PD-1 immunotherapy is linked to death and exhaustion of activated T and NK cell.

Methods

The co-culture system of HCC827 cells and peripheral mononuclear cells (PBMCs) was established to evaluate the effect of PD-1 mAb on the death rate and exhaustion of T and NK cell. The predisposing role of CD69 for death and exhaustion was validated by using PHA-activated PBMCs of CD69^low NSCLC patients. The 10-colour/three laser flow cytometer was used to test related markers for cell activation, death and exhaustion.

Results

We found that PD-1 mAb increase the death and exhaustion of T cells and NK cells in a dose-dependent way when PBMCs from NSCLC patients whose the percentages of CD69⁺ cells in peripheral blood T cells were greater than 5% (CD69^high NSCLC patients). By analyzing PBMCs from healthy volunteers and CD69^low NSCLC patients, we found that T cells and NK cells can be induced to die by PD-1 mAb after PHA activation, and had a tendency to raise the rate of cell exhaustion.

Conclusions

Our findings imply that increased death and exhaustion of CD69^high T cells and NK cells are associated with ineffective anti-PD-1 immunotherapy in lung cancer. The CD69 expression of T cells and NK cells may be developed as a potential predictor for acquired resistance of anti-PD-1 immunotherapy. These data may provide ideas to guide individualized medication of PD-1 mAb in NSCLC patients.

Immune System Influence on Hematopoietic Stem Cells and Leukemia Development

Hematopoietic stem cells (HSCs) are the source for all blood cells, including immune cells, and they interact dynamically with the immune system. This chapter will explore the nature of stem cells, particularly HSCs, in the context of their immune microenvironment. The dynamic interactions between stem cells and the immune system can have profound implications for current and future therapies, particularly regarding a potential "immune-privileged" HSC microenvironment. Immune/stem cell interactions change during times of stress and injury. Recent advances in cancer immunotherapy have overturned the long-standing belief that, being derived from the self, cancer cells should be immunotolerant. Instead, an immunosurveillance system recognizes and eliminates emergent pre-cancerous cells. Only in the context of a failing immunosurveillance system does cancer fully develop. Combined with the knowledge that stem cells or their unique properties can be critically important for cancer initiation, persistence, and resistance to therapy, understanding the unique immune properties of stem cells will be critical for the development of future cancer therapies. Accordingly, the therapeutic implications for leukemic stem cells (LSCs) inheriting an immune-privileged state from HSCs will be discussed. Through their dynamic interactions with a diverse immune system, stem cells serve as the light and dark root of cancer prevention vs. development.

Nidogen-2 (NID2) is a Key Factor in Collagen Causing Poor Response to Immunotherapy in Melanoma

Background

The incidence of cutaneous melanoma continues to rise rapidly and has an extremely poor prognosis. Immunotherapy strategies are the most effective approach for patients who have developed metastases, but not all cases have been successful due to the complex and variable mechanisms of melanoma response to immune checkpoint inhibition.

Methods

We synthesized collagen-coding gene expression data (second-generation and single-cell sequencing) from public Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. Bioinformatics analysis was performed using R software and several database resources such as Metascape database, Gene Set Cancer Analysis (GSCA) database, and Cytoscape software, etc., to investigate the biological mechanisms that may be related with collagens. Immunofluorescence and immunohistochemical staining were used to validate the expression and localization of Nidogen-2 (NID2).

Results

Melanoma patients can be divided into two collagen clusters. Patients with high collagen levels (C1) had a shorter survival than those with low collagen levels (C2) and were less likely to benefit from immunotherapy. We demonstrated that NID2 is a potential key factor in the collagen phenotype, is involved in fibroblast activation in melanoma, and forms a barrier to limit the proximity of CD8+ T cells to tumor cells.

Conclusion

We clarified the adverse effects of collagen on melanoma patients and identified NID2 as a potential therapeutic target.

A novel natural killer cell-related signatures to predict prognosis and chemotherapy response of pancreatic cancer patients

Background: Natural killer (NK) cells are involved in monitoring and eliminating cancers. The purpose of this study was to develop a NK cell-related genes (NKGs) in pancreatic cancer (PC) and establish a novel prognostic signature for PC patients. Methods: Omic data were downloaded from The Cancer Genome Atlas Program (TCGA), Gene Expression Omnibus (GEO), International Cancer Genome Consortium (ICGC), and used to generate NKG-based molecular subtypes and construct a prognostic signature of PC. NKGs were downloaded from the ImmPort database. The differences in prognosis, immunotherapy response, and drug sensitivity among subtypes were compared. 12 programmed cell death (PCD) patterns were acquired from previous study. A decision tree and nomogram model were constructed for the prognostic prediction of PC. Results: Thirty-two prognostic NKGs were identified in PC patients, and were used to generate three clusters with distinct characteristics. PCD patterns were more likely to occur at C1 or C3. Four prognostic DEGs, including MET, EMP1, MYEOV, and NGFR, were found among the clusters and applied to construct a risk signature in TCGA dataset, which was successfully validated in PACA-CA and GSE57495 cohorts. The four gene expressions were negatively correlated with methylation level. PC patients were divided into high and low risk groups, which exerts significantly different prognosis, clinicopathological features, immune infiltration, immunotherapy response and drug sensitivity. Age, N stage, and the risk signature were identified as independent factors of PC prognosis. Low group was more easily to happened on PCD. A decision tree and nomogram model were successfully built for the prognosis prediction of PC patients. ROC curves and DCA curves demonstrated the favorable and robust predictive capability of the nomogram model. Conclusion: We characterized NKGs-derived molecular subtypes of PC patients, and established favorable prognostic models for the prediction of PC prognosis, which may serve as a potential tool for prognosis prediction and making personalized treatment in PC.

Effect of chemotherapy, immunotherapy, and targeted therapies on removal of indwelling pleural catheters in non-small cell lung cancer patients with malignant pleural effusions

BACKGROUND

Indwelling pleural catheters (IPCs) are a mainstay therapy for malignant pleural effusions (MPEs). Many patients treated with IPCs achieve pleurodesis. We aimed to identify the effect of systemic therapies for non-small cell lung cancer (NSCLC) on IPC removal in patients with associated MPEs.

METHODS

We completed a retrospective cohort study of adult IPC recipients with metastatic NSCLC at the pleural effusion clinic at the Royal Alexandra Hospital from 2009 to 2020. We used logistic regression to assess the rates of IPC removal and Cox regression to assess the time to IPC removal.

RESULTS

232 patients met inclusion criteria with 248 IPCs reviewed. The overall pleurodesis rate was 42.7% with a median time to pleurodesis of 68 (IQR 38-140) days. In univariate analysis, chemotherapy (OR 1.86, CI 0.99-3.49) and epidermal growth factor receptor (EGFR) targeted therapy (OR 3.81, CI 1.86-7.79) were associated with higher rates of pleurodesis. In multivariate analysis, increased rates of pleurodesis were associated with an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of ≤2 (OR 4.82, CI 2.24-10.37) and EGFR targeted therapy (OR 3.87, CI 1.80-8.32). Earlier IPC removal was associated with EGFR targeted therapy in both univariate (HR 1.84, CI 1.20-2.83) and multivariate analysis (HR 1.86, CI 1.19-2.92).

CONCLUSIONS

Treatment with EGFR targeted therapy is associated with increased rates and earlier removal of IPC in patients with NSCLC in our cohort. Further large cohort studies are required to determine if this relationship persists.

PSME2 identifies immune-hot tumors in breast cancer and associates with well therapeutic response to immunotherapy

Breast cancer (BrCa) is a heterogeneous disease, which leads to unsatisfactory prognosis in females worldwide. Previous studies have proved that tumor immune microenvironment (TIME) plays crucial roles in oncogenesis, progression, and therapeutic resistance in Breast cancer. However, biomarkers related to TIME features have not been fully discovered. Proteasome activator complex subunit 2 (PSME2) is a member of proteasome activator subunit gene family, which is critical to protein degradation mediated by the proteasome. In the current research, we comprehensively analyzed the expression and immuno-correlations of Proteasome activator complex subunit 2 in Breast cancer. Proteasome activator complex subunit 2 was significantly upregulated in tumor tissues but associated with well prognosis. In addition, Proteasome activator complex subunit 2 was overexpressed in HER2-positive Breast cancer but not related to other clinicopathological features. Interestingly, Proteasome activator complex subunit 2 was positively related to immune-related processes and identified immuno-hot TIME in Breast cancer. Specifically, Proteasome activator complex subunit 2 was positively correlated with immunomodulators, tumor-infiltrating immune cells (TIICs), immune checkpoints, and tumor mutation burden (TMB) levels. Moreover, the positive correlation between Proteasome activator complex subunit 2 and PD-L1 expression was confirmed in a tissue microarray (TMA) cohort. Furthermore, in an immunotherapy cohort of Breast cancer, patients with pathological complete response (pCR) expressed higher Proteasome activator complex subunit 2 compared with those with non-pathological complete response. In conclusion, Proteasome activator complex subunit 2 is upregulated in tumor tissues and correlated with the immuno-hot tumor immune microenvironment, which can be a novel biomarker for the recognition of tumor immune microenvironment features and immunotherapeutic response in Breast cancer.

Case report: A case of duodenal adenocarcinoma achieving significantly long survival treating with immune checkpoint inhibitors and chemotherapy without positive biomarkers

Small bowel adenocarcinoma (SBA), particularly duodenal adenocarcinoma (DA), is a rare gastrointestinal cancer with a dismal prognosis. Data on SBA treatments are limited, and the therapeutic strategy remains uncertain. Currently, chemotherapy is the most used treatment; however, it has a poor median progression-free survival (mPFS) of no more than five months in the second-line setting. We report a case with DA that responded well to the immune checkpoint inhibitor (ICI) tislelizumab plus irinotecan in the second-line treatment. To our knowledge, this is the first report of administering ICIs plus chemotherapy to SBA. Despite the absence of microsatellite instability-high (MSI-H) and high tumor mutational burden (TMB), the patient with TP53/KRAS mutation achieved a significantly long PFS of 17 months, and the benefit is still ongoing. The mechanism of this remarkable efficacy might be associated with an increase in tumor immunogenicity after chemotherapy. The current study presents a promising effect of ICIs plus chemotherapy on SBA, affirming the need to investigate the clinical value of this combination in SBA and the underlying mechanism behind it.