Effective Cancer Immunotherapy Research Articles

Targeting HIF-1α abrogates PD-L1-mediated immune evasion in tumor microenvironment but promotes tolerance in normal tissues.

A combination of anti–CTLA-4 plus anti–PD-1/PD-L1 is the most effective cancer immunotherapy but causes high incidence of immune-related adverse events (irAEs). Here we report that targeting of HIF-1α suppressed PD-L1 expression on tumor cells and tumor-infiltrating myeloid cells, but unexpectedly induced PD-L1 in normal tissues by an IFN-γ–dependent mechanism. Targeting the HIF-1α/PD-L1 axis in tumor cells reactivated tumor-infiltrating lymphocytes and caused tumor rejection. The HIF-1α inhibitor echinomycin potentiated the cancer immunotherapeutic effects of anti–CTLA-4 therapy, with efficacy comparable to that of anti–CTLA-4 plus anti–PD-1 antibodies. However, while anti–PD-1 exacerbated irAEs triggered by ipilimumab, echinomycin protected mice against irAEs by increasing PD-L1 levels in normal tissues. Our data suggest that targeting HIF-1α fortifies the immune tolerance function of the PD-1/PD-L1 checkpoint in normal tissues but abrogates its immune evasion function in the tumor microenvironment to achieve safer and more effective immunotherapy.

Combined nano cancer immunotherapy based on immune status in a tumor microenvironment.

Since the effect of cancer immunotherapy is largely dependent on the status of the immune system in the tumor microenvironment (TME), choice of therapy and the development of new therapies based on the immune status in the TME would be predicted to be effective. Unfortunately, the development of delivery systems for such therapy has been slow. Here, we defined a parameter of immune status in TME showing antitumor effects and demonstrated the cancer immunotherapy with an adjuvant loaded lipid nanoparticle (LNP), which was taken advantage the parameter. An analysis was carried out to determine the relationship between antitumor effects and gene expression (22 target genes) in tumors (MC38 and E.G7-OVA) that respond to the programmed cell death 1 (PD-1) antibody and non-responding tumors (B16-F10 and 4T1). The immune status showing an effective antitumor effect, which consisted of 10 genes, was then extracted. Treatment with the adjuvant loaded LNP caused a significant antitumor effect against an E.G7-OVA tumor, and the gene expression in the E.G7-OVA tumor was completely within the range of gene expression for showing an effective antitumor effect, as defined by the identified immune status panel (IS-panel-10). Although the treatment with the adjuvant loaded LNP failed to induce a sufficient antitumor effect against the 4T1 tumor, we succeeded in enhancing the antitumor effect by using a combination therapy that was adopted based on the analysis by the IS-panel-10 in the TME. The 10 genes were found to affect the prognosis in a variety of human cancers. Collectively, the findings reported herein demonstrate the potential of immune status analysis in the TME for developing cancer immunotherapies using a delivery system.

Defining the cooperation between T cell responses to MHC-I and MHC-II melanoma neoantigens towards developing effective personalized cancer immunotherapies.

Abstract Immune checkpoint therapy (ICT) (e.g. anti-CTLA-4, anti-PD-1) enables durable T-cell dependent anti-tumor immunity in patients with solid tumors. Since not all patients respond to ICT, this work aims at developing a more in-depth understanding of T-cell responses to MHC class I (MHC-I) and MHC class II (MHC-II) tumor antigens that occur as a consequence of aberrant expression of non-mutant antigens or driver and passenger mutations that form tumor neoantigens. We used a poorly immunogenic Brafv600e Pten−/−Cdkn2a−/− YUMM1.7 (Y1.7) murine melanoma line that with a paucity of endogenous neoantigens that is unresponsive to ICT, and introduced model neoantigens previously identified in a murine sarcoma tumor line expressing the same MHC haplotype as the Y1.7 line. The MHC-I neoantigen used was formed by a G1254V point mutation in the Laminin alpha subunit-4 (Lama4) and the MHC-II neoantigen was formed by an A710T point mutation in Integrin beta-1 (Itgb1). Anti-CTLA-4-treated mice bearing the parental Y1.7 melanoma displayed progressive tumor growth, whereas the modified Y1.7 line expressing mLama4 and mItgb1 (Y1.7.mLama4.mItgb1) was rendered sensitive to ICT. Preliminary data showed that anti-CTLA-4 treated Y1.7.mLama4.mItgb1 tumors reject in mice in a CD4+ T cell and CD8+ T cell-dependent manner. Additionally, intratumoral mLama4-specific CD8+ T cells were detected in anti-CTLA-4-treated Y1.7.mLama4.mItgb1 melanoma bearing mice. Overall this model will allow us to better understand T cell mediated anti-tumor responses to both MHC-I and MHC-II neoantigens, as well as shared, non-mutant melanoma antigens (e.g. Pmel/GP100 and Trp2), which may facilitate development of improved neoantigen-based personalized immunotherapies.

A comparison of monoclonal antibodies against murine PD-1 and PD-L1

Abstract Blockade of the PD-L1/PD-1 pathway has proven to be a broadly effective cancer immunotherapy. FDA-approved therapeutic monoclonal antibodies (mAb) targeting the pathway have high affinity, blocking capacity, and low antibody effector activity. A number of rat anti-mouse mAbs have been used to model cancer immunotherapy in mouse models. We set forth the amino acid sequences of mAbs specific for mouse PD-1 (29F.1A12) and PD-L1 (10F.9G2) and compare their avidities, blocking capacities, biological activities, and epitope recognition with other commonly used mAbs. Of note, we found that 29F.1A12 had an approximately 100-fold better affinity and blocking capacity than RMP1-14. Further manipulation of these sequences should facilitate better modeling of immunotherapy in mouse models and the generation of novel agents. Supported by grants from the National Institutes of Health (P01 AI56299 and P01 CA236749).

Antibody-mediated blockade of the IL23 receptor destabilizes intratumoral regulatory T cells and enhances immunotherapy

Regulatory T cells (Treg) can impede antitumor immunity and currently represent a major obstacle to effective cancer immunotherapy. Targeting tumor-infiltrating regulatory Treg while sparing systemic Treg represents an optimal approach to this problem. Here, we provide evidence that the interleukin 23 receptor (IL23R) expressed by tumor-infiltrating Treg promotes suppressive activity. Disruption of the IL23R results in increased responsiveness of destabilized Treg to the IL12 cytokine, the production of γ-interferon, and the recruitment of CD8 T cells that inhibit tumor growth. Since the Treg destabilization pathway that is initiated by IL23R blockade is distinct and independent from the destabilization pathway coupled to glucocorticoid-induced TNFR-related protein (GITR) activation, we examined the impact of the coordinate induction of the two destabilization pathways on antitumor immune responses. Combined GITR and IL23R antibody treatment of mice inoculated with MC38 tumors resulted in robust and synergistic antitumor responses. These findings indicate that the delineation of independent Treg destabilization pathways may allow improved approaches to the development of combination immunotherapy for cancers.

In vivo activated T cell targeting with PD-1/PD-L1 blockade for sequential treatment mediated cancer immunotherapy

“Cold” tumor with insufficient CD8+ T cell infiltration and the up-regulated programmed cell death protein 1 (PD-1) on activated T cell surface are the two main obstacles in preventing effective cancer immunotherapy. Herein, we firstly leverage pH-responsive micelles (pRML) with photosensitizer 2-(1-hexyloxyethyl)−2-devinyl pyropheophorbide-a (HPPH) encapsulation (pRML/HPPH) via photodynamic-immunotherapy to pre-activate CD8+ T cells. Subsequently, pH-responsive polymersomes (pRPS) with interleukin-2 (IL-2) encapsulation and anti PD-1 fragment (Fab’) decoration on surface (Fab-pRPS/IL-2) are fabricated to target the pre-activated T cells with immune checkpoint blockade and T cell proliferation. From in vivo study results, the sequential cancer immunotherapy of pRML/HPPH and Fab-pRPS/IL-2 reveals high antitumor activity and abscopal effect in B16F10 tumor-bearing mice, as well as displays more effective antitumor activity than co-injection method. This work provides an approach to enhancing immune response via sequential therapy to target the pre-activated T cells with immune checkpoint blockade.

A Sub-6 nm MnFe2O4-dichloroacetic acid nanocomposite modulates tumor metabolism and catabolism for reversing tumor immunosuppressive microenvironment and boosting immunotherapy

Adenosine and lactate accumulated in tumor microenvironment are two major causes of immunosuppression, their concurrent downregulation holds promise in effective cancer immunotherapy, but remains challenging. Here, a sub-6 nm MnFe2O4 conjugated with dichloroacetic acid (DCA) nanoparticle is developed to modulate tumor glucose metabolism and ATP catabolism for reversing the tumor immunosuppressive microenvironment. The ultrasmall MnFe2O4-DCA nanoparticle can efficiently enter mitochondria and supply oxygen, improving the bioactivity of DCA to regulate glucose metabolism and reduce lactate production ca. 100 times higher than free DCA itself. Moreover, this design significantly downregulates CD39 and CD73 expression than DCA or MnFe2O4 alone, which consequently decreases the extracellular ATP catabolism. The concurrent regulation of glucose metabolism and ATP catabolism leads to increased immunostimulatory ATP level and decreased immunosuppressive adenosine and lactate levels in tumor microenvironment, eventually amplified dendritic cells maturation, enhanced cytotoxic T lymphocyte response, and improved cancer immunotherapy efficacy.

Pharmacological intervention of cholesterol sulfate-mediated T cell exclusion promotes antitumor immunity

Effective cancer immunotherapy requires physical contact of T cells with cancer cells. However, tumors often constitute special microenvironments that exclude T cells and resist immunotherapy. Cholesterol sulfate (CS) is a product of sulfotransferase SULT2B1b and acts as an endogenous inhibitor of DOCK2, a Rac activator essential for migration and activation of lymphocytes. We have recently shown that cancer-derived CS prevents tumor infiltration by effector T cells. Therefore, SULT2B1b may be a therapeutic target to dampen CS-mediated immune evasion. Here, we identified 3β-hydroxy-5-cholenoic acid (3β-OH-5-Chln) as a cell-active inhibitor of SULT2B1b. 3β-OH-5-Chln inhibited the cholesterol sulfotransferase activity of SULT2B1b in vitro and suppressed CS production from cancer cells expressing SULT2B1b. In vivo administration of 3β-OH-5-Chln locally reduced CS level in murine CS-producing tumors and increased infiltration of CD8+ T cells. When combined with immune checkpoint blockade or antigen-specific T cell transfer, 3β-OH-5-Chln suppressed the growth of CS-producing tumors. These results demonstrate that pharmacological inhibition of SULT2B1b can promote antitumor immunity through suppressing CS-mediated T cell exclusion.

Vascularized Lung Cancer Model for Evaluating the Promoted Transport of Anticancer Drugs and Immune Cells in an Engineered Tumor Microenvironment.

The tumor microenvironment (TME) is the environment around the tumor, including blood vessels, immune cells, fibroblasts, signaling molecules, and the extracellular matrix (ECM). Owing to its component interactions, the TME influences tumor growth and drug delivery in a highly complex manner. Although several vascularized cancer models are developed to mimic the TME in vitro, these models cannot comprehensively reflect blood vessel-tumor spheroid interactions. Here, a method for inducing controlled tumor angiogenesis by engineering the microenvironment is presented. The interstitial flow direction regulates the direction of capillary sprouting, showing that angiogenesis occurs in the opposite direction of flow, while the existence of lung fibroblasts affects the continuity and lumen formation of sprouted capillaries. The vascularized tumor model shows enhanced delivery of anticancer drugs and immune cells to the tumor spheroids because of the perfusable vascular networks. The possibility of capillary embolism using anticancer drug-conjugated liquid metal nanoparticles is investigated using the vascularized tumor model. This vascularized tumor platform can aid in the development of effective anticancer drugs and cancer immunotherapy.

Promoting antibody-dependent cellular phagocytosis for effective macrophage-based cancer immunotherapy.

Macrophages are essential in eliciting antibody-dependent cellular phagocytosis (ADCP) of cancer cells. However, a satisfactory anticancer efficacy of ADCP is contingent on early antibody administration, and resistance develops along with cancer progression. Here, we investigate the mechanisms underlying ADCP and demonstrate an effective combinatorial strategy to potentiate its efficacy. We identified paclitaxel as a universal adjuvant that efficiently potentiated ADCP by a variety of anticancer antibodies in multiple cancers. Rather than eliciting cytotoxicity on cancer cells, paclitaxel polarized macrophages toward a state with enhanced phagocytic ability. Paclitaxel-treated macrophages down-regulated cell surface CSF1R whose expression was negatively correlated with patient survival in multiple malignancies. The suppression of CSF1R in macrophages enhanced ADCP of cancer cells, suggesting a role of CSF1R in regulating macrophage phagocytic ability. Together, these findings define a potent strategy for using conventional anticancer drugs to stimulate macrophage phagocytosis and promote the therapeutic efficacy of clinical anticancer antibodies.

Control of Dendritic Cell Function Within the Tumour Microenvironment.

The tumour microenvironment (TME) presents a major block to anti-tumour immune responses and to effective cancer immunotherapy. The inflammatory mediators such as cytokines, chemokines, growth factors and prostaglandins generated in the TME alter the phenotype and function of dendritic cells (DCs) that are critical for a successful adaptive immune response against the growing tumour. In this mini review we discuss how tumour cells and the surrounding stroma modulate DC maturation and trafficking to impact T cell function. Fibroblastic stroma and the associated extracellular matrix around tumours can also provide physical restrictions to infiltrating DCs and other leukocytes. We discuss interactions between the inflammatory TME and infiltrating immune cell function, exploring how the inflammatory TME affects generation of T cell-driven anti-tumour immunity. We discuss the open question of the relative importance of antigen-presentation site; locally within the TME versus tumour-draining lymph nodes. Addressing these questions will potentially increase immune surveillance and enhance anti-tumour immunity.

Injectable immunogel based on polymerized phenylboronic acid and mannan for cancer immunotherapy

The recent development and prospects of cancer immunotherapy have led to diversification of the types of therapeutic agents used. By simultaneously administering various agents, a more effective therapeutic effect can be expected due to the synergistic effects of multiple therapeutics. In particular, if a substance with adjuvanticity and tumor antigen is delivered at the same time, enhanced cancer immunotherapy can be achieved through high cross-presentation and antigen-presenting cell (APC) maturation. To this end, we developed a polymerized phenylboronic acid (pPBA)-based immunogel for the simultaneous delivery of mannan, which has adjuvanticity and tumor antigen. The immunogel was formed by simple mixing of the polysaccharide mannan with pPBA through the formation of phenylboronic ester between the diol of mannose monomers and phenylboronic acids of pPBA. The immunogel was slowly degraded by hydrolysis to release the loaded tumor antigen. In addition, the released mannan played a key role in both APC maturation in vitro and the upregulation of cross-presentation. Finally, the pPBA-mannan immunogel exhibited a significant anticancer effect in the 4 T1 cell-inoculated mouse model, implying the potential of a codelivery system of antigens and adjuvants for effective cancer immunotherapy.

EEF2K promotes PD-L1 stabilization through inactivating GSK3β in melanoma

BackgroundImmune checkpoint blockade (ICB) targeting programmed death ligand-1 (PD-L1)/programmed cell death protein-1 (PD-1) pathway has become an attractive strategy for cancer treatment; however, unsatisfactory efficacy has limited its clinical benefits....

Hybrid-Membrane-Decorated Prussian Blue for Effective Cancer Immunotherapy via Tumor-Associated Macrophages Polarization and Hypoxia Relief.

Both tumor-associated macrophages (TAMs) and hypoxia condition severely restrict the antitumor potency during cancer immunotherapy. It is essential to overcome the two issues for improving therapeutic efficacy. In this study, a hollow mesoporous Prussian blue (HMPB) nanosystem with mannose decoration and hydroxychloroquine (HCQ) adsorption is built, to form Man-HMPB/HCQ. It can facilitate cellular internalization via mannose-receptor mediated endocytosis and induce TAM polarization via iron ion/HCQ release with HMPB degradation. The hybrid macrophage and thylakoid (TK) membrane is camouflaged on the Man-HMPB/HCQ surface, denoted as TK-M@Man-HMPB/HCQ, to reduce in vivo reticuloendothelial system uptake, enhance tumor accumulation, and mitigate hypoxia. The in vivo results indicate that TK-M@Man-HMPB/HCQ notably inhibits tumor growth, induces TAM polarization, facilitates cytotoxic T lymphocytes infiltration, and alleviates hypoxia microenvironment. The rational design may provide a new pathway to modulate the tumor microenvironment for promoting cancer immunotherapy effects.

Ferroptosis‐Enhanced Cancer Immunity by a Ferrocene‐Appended Iridium(III) Diphosphine Complex

AbstractFerroptosis is a programmed cell death pathway discovered in recent years, and ferroptosis‐inducing agents have great potential as new antitumor candidates. Here, we report a IrIII complex (Ir1) containing a ferrocene‐modified diphosphine ligand that localizes in lysosomes. Under the acidic environments of lysosomes, Ir1 can effectively catalyze Fenton‐like reaction, produce hydroxyl radicals, induce lipid peroxidation, down‐regulate glutathione peroxidase 4, and result in ferroptosis. RNA sequencing analysis shows that Ir1 can significantly affect pathways related to ferroptosis and cancer immunity. Accordingly, Ir1 can induce immunogenic cells death and suppress tumor growth in vitro, regulate T cell activity and immune microenvironments in vivo. In conclusion, we show the potential of small molecules with ferroptosis‐inducing capabilities for effective cancer immunotherapy.

Ferroptosis-Enhanced Cancer Immunity by a Ferrocene-Appended Iridium(III) Diphosphine Complex.

Ferroptosis is a programmed cell death pathway discovered in recent years, and ferroptosis-inducing agents have great potential as new antitumor candidates. Here, we report a IrIII complex (Ir1) containing a ferrocene-modified diphosphine ligand that localizes in lysosomes. Under the acidic environments of lysosomes, Ir1 can effectively catalyze Fenton-like reaction, produce hydroxyl radicals, induce lipid peroxidation, down-regulate glutathione peroxidase 4, and result in ferroptosis. RNA sequencing analysis shows that Ir1 can significantly affect pathways related to ferroptosis and cancer immunity. Accordingly, Ir1 can induce immunogenic cells death and suppress tumor growth in vitro, regulate T cell activity and immune microenvironments in vivo. In conclusion, we show the potential of small molecules with ferroptosis-inducing capabilities for effective cancer immunotherapy.

Abstract ES11-3: Optimizing immunotherapy efficacy in the clinic through biomarkers: Advances in single cell and spatial histology analyse

Abstract Single cell technologies and spatial analyses are emerging as powerful tools to investigate tumor heterogeneity, cell state of key effector or suppressing immune cells and detailed distribution of cells within the tumor microenvironment. Their application will undoubtedly provide further understanding of the effects of cancer immunotherapy on the tumor microenvironment, which is particularly important for the largely non-immunogenic breast carcinomas. However, analyses of clinical samples require well-coordinated, multidisciplinary teams and specific expertise. Moreover, large scale analyses have major technical challenges and is still relatively costly. We will discuss the promise and hurdles of single cell and spatial analyses on the road to find biomarker for breast cancer immunotherapy and avenues for novel immunomodulatory treatments for breast cancer patients. Citation Format: M Kok. Optimizing immunotherapy efficacy in the clinic through biomarkers: Advances in single cell and spatial histology analyse [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr ES11-3.

Oncolytic Vaccinia Virus in Lung Cancer Vaccines.

Therapeutic cancer vaccines represent a promising therapeutic modality via the induction of long-term immune response and reduction in adverse effects by specifically targeting tumor-associated antigens. Oncolytic virus, especially vaccinia virus (VV) is a promising cancer treatment option for effective cancer immunotherapy and thus can also be utilized in cancer vaccines. Non-small cell lung cancer (NSCLC) is likely to respond to immunotherapy, such as immune checkpoint inhibitors or cancer vaccines, since it has a high tumor mutational burden. In this review, we will summarize recent applications of VV in lung cancer treatment and discuss the potential and direction of VV-based therapeutic vaccines.

Regulating Histone Deacetylase Signaling Pathways of Myeloid-Derived Suppressor Cells Enhanced T Cell-Based Immunotherapy.

Immunotherapy has emerged as a promising approach to combat immunosuppressive tumor microenvironment (TME) for improved cancer treatment. FDA approval for the clinical use of programmed death receptor 1/programmed death-ligand 1 (PD-1/PD-L1) inhibitors revolutionized T cell-based immunotherapy. Although only a few cancer patients respond to this treatment due to several factors including the accumulation of immunosuppressive cells in the TME. Several immunosuppressive cells within the TME such as regulatory T cells, myeloid cells, and cancer-associated fibroblast inhibit the activation and function of T cells to promote tumor progression. The roles of epigenetic modifiers such as histone deacetylase (HDAC) in cancer have long been investigated but little is known about their impact on immune cells. Recent studies showed inhibiting HDAC expression on myeloid-derived suppressor cells (MDSCs) promoted their differentiation to less suppressive cells and reduced their immunosuppressive effect in the TME. HDAC inhibitors upregulated PD-1 or PD-L1 expression level on tumor or immune cells sensitizing tumor-bearing mice to anti-PD-1/PD-L1 antibodies. Herein we discuss how inhibiting HDAC expression on MDSCs could circumvent drawbacks to immune checkpoint inhibitors and improve cancer immunotherapy. Furthermore, we highlighted current challenges and future perspectives of HDAC inhibitors in regulating MDSCs function for effective cancer immunotherapy.

Intravenous liposomal vaccine enhances CTL generation, but not until antigen presentation

Adjuvant loaded nanoparticles are a potent strategy for developing effective combined cancer immunotherapies. A polyinosinic-polycytidylic acid (poly I:C) is a ligand for toll-like receptor 3 and a promising cancer adjuvant. However, regarding intravenous administration, the potential for and the mechanism of poly I:C loaded nanoparticles as a cancer vaccine are largely unknown. We investigated the effects of using a combination of poly I:C and an antigen loaded liposome for cancer immunotherapy and a key process for achieving effective antitumor immunity of the liposome system under conditions of intravenous vaccination. A poly I:C and ovalbumin (OVA) loaded octaarginine (R8) modified liposome (PoIC/OVA-R8L) drastically inhibited the systemic cytokine production derived from the poly I:C intravenous injection. Treatment with PoIC/OVA-R8L improved the immune status in B16-OVA tumors to an inflamed immune status and induced a significant combined antitumor effect with the anti-programmed cell death 1 ligand (PD-L1). In a mechanistic analysis compared with a high dose of the free form of poly I:C, interestingly, local cytokine production, maturation of antigen presenting cells and antigen presentation were comparable. Conversely, significant differences were identified in the processes after OVA-specific CTL generation. Collectively, our findings have implications for the development of intravenous liposomal vaccines.