Robust IL-2-dependent antitumor immunotherapy requires targeting the high-affinity IL-2R on tumor-specific CD8+ T cells

Safety toxicology of an IL-2 'no-alpha' mutein in the Sprague-Dawley rat following repeated dosing via intravenous administration

The potential toxicity, safety and anti-drug antibody production of the novel IL-2 "no-alpha" mutein is in need of investigation as it may be a critical candidate for cancer therapy. The design of this mutein is meant to reduce toxicity compared to the IL-2 wildtype by disrupting interactions with the alpha receptor (CD25) and increasing the efficacy of the treatment. This was assessed following administration to Sprague-Dawley rats intravenously (IV), and it occurred over three cycles of five days each with daily dosing, with a 9-day washout period between each cycle. For the mutein dose groups, animals were dosed via IV at dose levels of 600, 6000, 18,000 U/kg. This dosing regimen is equivalent to 1x, 10x, and 30x the proposed first human dose, respectively. This study also assessed the progression or regression of any effects following a 14-day treatment-free recovery period for the control and high dose groups. Rats that were administered the "no-alpha" mutein at 600 and 6000 U/kg were well-tolerated with no apparent abnormal observations in general health, behaviour and autonomic function. There was no evidence of systemic toxicity based on evaluations in clinical pathology, gross necropsy and histopathology. At 18,000 U/kg (30x), abnormal clinical signs were observed at the injection sites consisting of localized swelling, discoloration, scabbing and necrosis. These animals showed a significant recovery in abnormal localized clinical signs following the treatment free period. Additionally other parameters did not indicate any significantly detrimental effects at this dose level. Therefore, the IL-2 mutein "no-alpha" seems to hold promise as a valuable addition to the current array of cancer therapy strategies, especially at the proposed dose level.

Activated platelets stimulate effector CD8+ T cells to enhance HNSCC immunotherapy efficacy

Programmed Death Receptor-1 (PD-1) is an immune checkpoint receptor expressed on the surface of T cells. Monoclonal antibodies targeting PD-1 and its ligand, PD-L1, are among the most widely utilized immune checkpoint inhibitors in cancer immunotherapy, dramatically improving the prognosis of patients with various malignancies. Traditionally, platelets, which are cytoplasmic fragments derived from megakaryocytes, have been primarily recognized for their roles in hemostasis and coagulation. However, recent studies have highlighted the emerging role of platelets in cancer biology and therapy. Platelets can modulate immune cell functions through various mechanisms, including the release of bioactive molecules and direct interactions with immune cells. A deeper understanding of the interplay between platelets and immune responses could pave the way for novel therapeutic strategies in cancer treatment. In our research, in patients with better treatment responses, there are higher levels of mature and activated CD8+ T cells in their PBMCs prior to treatment. Additionally, the activation of platelets is also more pronounced, and the proteins expressed on these platelets may modulate immune cells. After receiving immunotherapy, patients in the responsive (R) group exhibited a higher abundance of activated effector CD8+ T cells, which demonstrated stronger immune response capabilities. Furthermore, the increased levels of activated platelets in the R group may contribute to the regulation of CD8+ effector memory T cells, influencing their quantity and function. Our study suggests that the functional state of CD8+ T cells and the level of activated platelets prior to treatment may serve as predictive indicators for the efficacy of PD-1 inhibitors in head and neck cancer patients. Activated CD8+ effector T cells may contribute to the differences in immunotherapy responses, with activated platelets playing a role in promoting the maturation and activation of CD8+ effector memory T cells.These insights help better understand the interactions between platelets and immune cells, particularly emphasizing the role of CD8+ effector memory T cells in immunotherapy. Additionally, they offer potential strategies for predicting patient responses to PD-1 inhibitor treatment and optimizing the efficacy of immunotherapy.

Harnessing cytokine immunocomplexes and cytokine fusion proteins for cancer Therapy: Mechanisms and clinical potential

Cytokines are pivotal regulators of cellular functions and immune responses, making them highly promising targets for cancer immunotherapy. Despite their widespread clinical application, the effectiveness of cytokine immunotherapy is often hampered by their pleiotropic effects, short half-lives, uneven biodistribution, and severe side effects at high dosages. Recent advancements in cytokine biology have led to the development of cytokine-antibody immunocomplexes and cytokine fusion proteins, offering a new paradigm in cancer treatments. These innovations foster the ability of cytokines to selectively activate specific cancer-targeting immune cell populations, such as CD8 T cells and NK cells, effectively inhibiting tumour progression. Furthermore, both therapeutic approaches can mitigate systemic toxicities and prolong the biological activity of cytokines in the body. This review delves into the recent advancements of cytokine immunocomplexes and cytokine fusion proteins, with a particular focus on interleukin-2 (IL-2), IL-7 and IL-15, which are in clinical/preclinical development. Moreover, we discuss the therapeutic benefits of these approaches observed in recent preclinical and clinical studies, along with the challenges that must be addressed to fully unlock their potential in cancer immunotherapy.

Site-specific pegylated IL2 mutein with biased IL2 receptor binding for cancer immunotherapy

While Interleukin 2 (IL2) has the capability to activate both NK and T cells robustly, its limited in vivo half-life, considerable toxicity, and tendency to boost Treg cells pose significant challenges, restricting its widespread application in cancer therapy. In this investigation, we engineered a novel IL2 variant (IL2-4M-PEG) with reduced CD25 binding activity and an extended half-life by substituting amino acids associated with CD25 binding and implementing site-directed PEGylation. IL2-4M-PEG notably amplifies effector cells over Treg cells. Furthermore, our findings reveal that IL2-4M-PEG, characterized by an extended half-life, exhibits anti-tumor effects in a mouse model. Consequently, this innovative IL2 holds the potential for enhancing combined cancer therapies in the future.

IL-2 based cancer immunotherapies: an evolving paradigm

Discovered over 4 decades ago in the supernatants of activated T cells, interleukin-2 (IL-2) is a potent pleiotropic cytokine involved in the regulation of immune responses. It is required for effector T cell expansion and differentiation as well as for peripheral tolerance induced by regulatory T cells. High-dose IL-2 treatment was the first FDA-approved immunotherapy for renal cell carcinoma and melanoma, achieving single agent complete and durable responses, albeit only in a small proportion of patients. The therapeutic potential of wild type IL-2 is clinically limited by its short half-life and severe vascular toxicity. Moreover, the activation of regulatory T cells and the terminal differentiation of effector T cells on IL-2 pose additional restrictions. To overcome the toxicity of IL-2 in order to realize its full potential for patients, several novel engineering strategies are being developed and IL-2 based immunotherapy for cancer has emerged as a burgeoning field of clinical and experimental research. In addition, combination of IL-2 with PD-1/L1 pathway blockade shows vastly improved anti-tumor efficacy over either monotherapy in preclinical tumor models. In this review we discuss the biological characteristics of IL-2 and its receptors, as well as its efficacy and treatment limiting toxicities in cancer patients. We also explore the efforts aimed at developing novel and safer IL-2 therapies to harness the full therapeutic potential of this cytokine.

Harnessing CD8 T cell responses using PD-1-IL-2 combination therapy

There is considerable interest in developing more effective programmed cell death (PD)-1 combination therapies against cancer. One major obstacle to these efforts is a dysfunctional/exhausted state of CD8 T cells, which PD-1 monotherapy is not able to overcome. Recent studies have highlighted that PD-1+ T cell factor (TCF)-1+ stem-like CD8 T cells are not fate locked into the exhaustion program and their differentiation trajectory can be changed by interleukin (IL)-2 signals. Modifying the CD8 T cell exhaustion program and generating better effectors from stem-like CD8 T cells by IL-2 form the fundamental immunological basis for combining IL-2 with PD-1 therapy. Many versions of IL-2-based products are being tested and each product should be carefully evaluated for its ability to modulate dysfunctional states of anti-tumor CD8 T cells.

An Updated Review of Interleukin-2 Therapy in Cancer and Autoimmune Diseases

Interleukin-2 (IL-2) is a cytokine that acts in dual and paradoxical ways in the immunotherapy of cancers and autoimmune diseases. Numerous clinical trial studies have shown that the use of different doses of this cytokine in various autoimmune diseases, transplantations, and cancers has resulted in therapeutic success. However, side effects of varying severity have been observed in patients. In recent years, to prevent these side effects, IL-2 has been engineered to bind more specifically to its receptors on the cell surface, decreasing IL-2 toxicities in patients. In this review article, we focus on some recent clinical trial studies and analyze them to determine the appropriate dose of IL-2 drug with the least toxicities. In addition, we discuss the engineering performed on IL-2, which shows that engineered IL-2 increases the specificity function of IL-2 and decreases its adverse effects.

Interleukin-2 signaling in the regulation of T cell biology in autoimmunity and cancer

Interleukin-2 (IL-2) is a critical cytokine for T cell peripheral tolerance and immunity. Here, we review how IL-2 interaction with the high-affinity IL-2 receptor (IL-2R) supports the development and homeostasis of regulatory T cells and contributes to the differentiation of helper, cytotoxic, and memory T cells. A critical element for each T cell population is the expression of CD25 (Il2rα), which heightens the receptor affinity for IL-2. Signaling through the high-affinity IL-2R also reinvigorates CD8+ exhausted T (Tex) cells in response to checkpoint blockade. We consider the molecular underpinnings reflecting how IL-2R signaling impacts these various T cell subsets and the implications for enhancing IL-2-dependent immunotherapy of autoimmunity, other inflammatory disorders, and cancer.

Inflammation and Neurodegeneration in Glaucoma: Isolated Eye Disease or a Part of a Systemic Disorder? - Serum Proteomic Analysis

Introduction

Glaucoma is the most common optic neuropathy and the leading cause of irreversible blindness worldwide, which affects 3.54% of the population aged 40-80 years. Despite numerous published studies, some aspects of glaucoma pathogenesis, serum biomarkers, and their potential link with other diseases remain unclear. Recent articles have proposed that autoimmune, oxidative stress and inflammation may be involved in the pathogenesis of glaucoma.

Methods

We investigated the serum expression of 92 inflammatory and neurotrophic factors in glaucoma patients. The study group consisted of 26 glaucoma patients and 192 healthy subjects based on digital fundography.

Results

Patients with glaucoma had significantly lower serum expression of IL-2Rβ, TWEAK, CX3CL1, CD6, CD5, LAP TGF-beta1, LIF-R, TRAIL, NT-3, and CCL23 and significantly higher expression of IL-22Rα1.

Conclusion

Our results indicate that patients with glaucoma tend to have lower levels of neuroprotective proteins and higher levels of neuroinflammatory proteins, similar to those observed in psychiatric, neurodegenerative and autoimmune diseases, indicating a potential link between these conditions and glaucoma pathogenesis.

Infiltration of CD3+ and CD8+ lymphocytes in association with inflammation and survival in pancreatic cancer

BACKGROUND

Pancreatic ductal adenocarcinomas (PDAC) have heterogeneous tumor microenvironments relatively devoid of infiltrating immune cells. We aimed to quantitatively assess infiltrating CD3+ and CD8+ lymphocytes in a treatment-naïve patient cohort and assess associations with overall survival and microenvironment inflammatory proteins.

METHODS

Tissue microarrays were immunohistochemically stained for CD3+ and CD8+ lymphocytes and quantitatively assessed using QuPath. Levels of inflammation-associated proteins were quantified by multiplexed, enzyme-linked immunosorbent assay panels on matching tumor and tissue samples.

RESULTS

Our findings revealed a significant increase in both CD3+ and CD8+ lymphocytes populations in PDAC compared with non-PDAC tissue, except when comparing CD8+ percentages in PDAC versus intraductal papillary mucinous neoplasms (IPMN) (p = 0.5012). Patients with quantitatively assessed CD3+ low tumors (lower 50%) had shorter survival (median 273 days) compared to CD3+ high tumors (upper 50%) with a median overall survival of 642.5 days (p = 0.2184). Patients with quantitatively assessed CD8+ low tumors had significantly shorter survival (median 240 days) compared to CD8+ high tumors with a median overall survival of 1059 days (p = 0.0003). Of 41 proteins assessed in the inflammation assay, higher levels of IL-1B and IL-2 were significantly associated with decreased CD3+ infiltration (r = -0.3704, p = 0.0187, and r = -0.4275, p = 0.0074, respectively). Higher levels of IL-1B were also significantly associated with decreased CD8+ infiltration (r = -0.4299, p = 0.0045), but not IL-2 (r = -0.0078, p = 0.9616). Principal component analysis of the inflammatory analytes showed diverse inflammatory responses in PDAC.

CONCLUSION

In this work, we found a marked heterogeneity in infiltrating CD3+ and CD8+ lymphocytes and individual inflammatory responses in PDAC. Future mechanistic studies should explore personalized therapeutic strategies to target the immune and inflammatory components of the tumor microenvironment.

IL-2-driven CD8+ T cell phenotypes: implications for immunotherapy

The therapeutic potential of interleukin (IL)-2 in cancer treatment has been known for decades, yet its widespread adoption in clinical practice remains limited. Recently, chimeric proteins of an anti-PD-1 antibody and suboptimal IL-2 variants were shown to stimulate potent antitumor and antiviral immunity by inducing unique effector CD8+ T cells in mice. A similar subset of cytotoxic T cells is induced by depletion of regulatory T cells (Tregs), suggesting IL-2 sequestration as a major mechanism through which regulatory T cells suppress activated CD8+ T cells. Here, we present our view of how IL-2-based biologicals can boost the antitumor response at a cellular level, and propose that the role of Tregs following such treatments may have been previously overestimated.

Full spectrum flow cytometry-powered comprehensive analysis of PBMC as biomarkers for immunotherapy in NSCLC with EGFR-TKI resistance

BACKGROUND

Clinical studies suggest that immune checkpoint inhibitor (ICI) monotherapy has limited benefits in non-small cell lung cancer (NSCLC) patients after epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) failure. However, data about efficacy of ICI plus chemotherapy remain controversial, probably attributed to the heterogeneity among such population, and robust efficacy biomarkers are urgent to explore.

METHODS

A total of 60 eligible patients who received ICI plus chemotherapy after EGFR-TKI treatment failure were enrolled, 24 of whom peripheral blood mononuclear cell (PBMC) samples were collected at baseline and after 2 cycles of treatment. We have designed a 23-color-antibody panel to detect PBMC by full spectrum flow cytometry.

RESULTS

For EGFR-TKI resistant NSCLC patients: 1) ICI plus chemotherapy achieved an objective response rate (ORR) of 21.7% and a median progression-free survival (PFS) of 6.4 months. 2) clinical characteristics associated with worse efficacy included liver metastasis and platelet-to-lymphocyte ratio (PLR) > 200. 3) the proportion of immune cell subset associated with better efficacy was higher baseline effective CD4⁺T cells (E4). 4) the baseline expression of immune checkpoint proteins (ICPs) on cell subsets associated with better efficacy included: higher expression of CD25 on dendritic cells (DC) and central memory CD8⁺T cells (CM8), and higher expression of Lymphocyte activation gene 3 (LAG-3) on effective memory CD8⁺T cells (EM8). 5) the expression of ICPs after 2 cycles of treatment associated with better efficacy included: higher expression of CD25 on CD8⁺T/EM8 /natural killer (NK) cells. 6) the dynamic changes of ICPs expression associated with worse efficacy included: significantly decrease of T cell immunoglobulin and ITIM domain (TIGIT) expression on regular T cells (Tregs) and decrease of V-domain immunoglobulin suppressor of T cell activation (VISTA) expression on Th1. 7) a prediction model for the efficacy of ICI plus chemotherapy was successfully constructed with a sensitivity of 62.5%, specificity of 100%, and area under curve (AUC) = 0.817.

CONCLUSIONS

Some EGFR-TKI-resistant NSCLC patients could indeed benefit from ICI plus chemotherapy, but most patients are primary resistant to immunotherapy. Comprehensive analysis of peripheral immune cells using full spectrum flow cytometry showed that compared to the proportion of cell subsets, the expression type and level of ICPs on immune cells, especially CD25, were significantly correlated with the efficacy of immunotherapy.