Cell surface-tethered IL-12 repolarizes the tumor immune microenvironment to enhance the efficacy of adoptive T cell therapy

Adoptive Cell Therapy for Solid Tumors: Current Status in Melanoma and Next-Generation Therapies

Lifileucel or TIL has recently been FDA approved for metastatic melanoma patients as first cell therapy for a solid tumor. We discuss roll-out of TIL as new SOC and other upcoming new cell therapies.

T cell cascade regulation initiates systemic antitumor immunity through living drug factory of anti-PD-1/IL-12 engineered probiotics

Immune checkpoint blockade (ICB) has revolutionized cancer therapy but only works in a subset of patients due to the insufficient infiltration, persistent exhaustion, and inactivation of T cells within a tumor. Herein, we develop an engineered probiotic (interleukin [IL]-12 nanoparticle Escherichia coli Nissle 1917 [INP-EcN]) acting as a living drug factory to biosynthesize anti-PD-1 and release IL-12 for initiating systemic antitumor immunity through T cell cascade regulation. Mechanistically, INP-EcN not only continuously biosynthesizes anti-PD-1 for relieving immunosuppression but also effectively cascade promote T cell activation, proliferation, and infiltration via responsive release of IL-12, thus reaching a sufficient activation threshold to ICB. Tumor targeting and colonization of INP-EcNs dramatically increase local drug accumulations, significantly inhibiting tumor growth and metastasis compared to commercial inhibitors. Furthermore, immune profiling reveals that anti-PD-1/IL-12 efficiently cascade promote antitumor effects in a CD8+ T cell-dependent manner, clarifying the immune interaction of ICB and cytokine activation. Ultimately, such engineered probiotics achieve a potential paradigm shift from T cell exhaustion to activation and show considerable promise for antitumor bio-immunotherapy.

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

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

Inhalable extracellular vesicle delivery of IL-12 mRNA to treat lung cancer and promote systemic immunity

Lung carcinoma is one of the most common cancers and has one of the lowest survival rates in the world. Cytokines such as interleukin-12 (IL-12) have demonstrated considerable potential as robust tumour suppressors. However, their applications are limited due to off-target toxicity. Here we report on a strategy involving the inhalation of IL-12 messenger RNA, encapsulated within extracellular vesicles. Inhalation and preferential uptake by cancer cells results in targeted delivery and fewer systemic side effects. The IL-12 messenger RNA generates interferon-γ production in both innate and adaptive immune-cell populations. This activation consequently incites an intense activation state in the tumour microenvironment and augments its immunogenicity. The increased immune response results in the expansion of tumour cytotoxic immune effector cells, the formation of immune memory, improved antigen presentation and tumour-specific T cell priming. The strategy is demonstrated against primary neoplastic lesions and provides profound protection against subsequent tumour rechallenge. This shows the potential for locally delivered cytokine-based immunotherapies to address orthotopic and metastatic lung tumours.

Synergistic therapeutic strategies and engineered nanoparticles for anti-vascular endothelial growth factor therapy in cancer

Angiogenesis is one of the defining characteristics of cancer. Vascular endothelial growth factor (VEGF) is crucial for the development of angiogenesis. A growing interest in cancer therapy is being caused by the widespread use of antiangiogenic drugs in treating several types of human cancer. However, this therapeutic approach can worsen resistance, invasion, and overall survival. As we proceed, refining combination strategies and addressing the constraint of targeted treatments are paramount. Therefore, major challenges in using novel combinations of antiangiogenic agents with cytotoxic treatments are currently focused on illustrating the potential of synergistic therapeutic strategies, alongside advancements in nanomedicine and gene therapy, present opportunities for more precise interference with angiogenesis pathways and tumor environments. Nanoparticles have the potential to regulate several crucial activities and improve several drug limitations such as lack of selectivity, non-targeted cytotoxicity, insufficient drug delivery at tumor sites, and multi-drug resistance based on their unique features. The goal of this updated review is to illustrate the enormous potential of novel synergistic therapeutic strategies and the targeted nanoparticles as an alternate strategy for t treating a variety of tumors employing antiangiogenic therapy.

Cytokine signaling in chimeric antigen receptor T-cell therapy

Adoptive immunotherapy using chimeric antigen-receptor (CAR)-engineered T cells can induce robust antitumor responses against hematologic malignancies. However, its efficacy is not durable in the majority of the patients, warranting further improvement of T-cell functions. Cytokine signaling is one of the key cascades regulating T-cell survival and effector functions. In addition to cytokines that use the common γ chain as a receptor subunit, multiple cytokines regulate T-cell functions directly or indirectly. Modulating cytokine signaling in CAR-T cells by genetic engineering is one promising strategy to augment their therapeutic efficacy. These strategies include ectopic expression of cytokines, cytokine receptors, and synthetic molecules that mimic endogenous cytokine signaling. Alternatively, autocrine IL-2 signaling can be augmented through reprogramming of CAR-T cell properties through transcriptional and epigenetic modification. On the other hand, cytokine production by CAR-T cells triggers systemic inflammatory responses, which mainly manifest as adverse events such as cytokine-release syndrome (CRS) and neurotoxicity. In addition to inhibiting direct inflammatory mediators such as IL-6 and IL-1 released from activated macrophages, suppression of T-cell-derived cytokines associated with the priming of macrophages can be accomplished through genetic modification of CAR-T cells. In this review, I will outline recently developed synthetic biology approaches to exploit cytokine signaling to enhance CAR-T cell functions. I will also discuss therapeutic target molecules to prevent or alleviate CAR-T cell-related toxicities.

Noncanonical MAVS signaling restrains dendritic cell-driven antitumor immunity by inhibiting IL-12

Mitochondrial antiviral signaling protein (MAVS)-mediated cytosolic RNA sensing plays a central role in tumor immunogenicity. However, the effects of host MAVS signaling on antitumor immunity remain unclear. Here, we demonstrate that the host MAVS pathway supports tumor growth and impairs antitumor immunity, whereas MAVS deficiency in dendritic cells (DCs) promotes tumor-reactive CD8+ T cell responses. Specifically, CD8+ T cell priming capacity was enhanced by MAVS ablation in a type I interferon-independent, but IL-12-dependent, manner. Mechanistically, loss of the RIG-I/MAVS cascade activated the noncanonical NF-κB pathway and in turn induced IL-12 production by DCs. MAVS-restrained IL-12 promoted cross-talk between CD8+ T cells and DCs, which was licensed by IFN-γ. Moreover, ablation of host MAVS sensitized tumors to immunotherapy and attenuated radiation resistance, thereby facilitating the maintenance of effector CD8+ T cells. These findings demonstrate that the host MAVS pathway acts as an immune regulator of DC-driven antitumor immunity and support the development of immunotherapies that antagonize MAVS signaling in DCs.

Recombinant oncolytic adenovirus armed with CCL5, IL-12, and IFN-γ promotes CAR-T infiltration and proliferation in vivo to eradicate local and distal tumors

The efficacy of chimeric antigen receptor T (CAR-T) cells for solid tumors remains unsatisfactory due to the limited tumor infiltration and immunosuppressive microenvironment. To overcome these limitations, the genetically engineered recombinant oncolytic adenoviruses (OAVs) that conditionally replicate in tumor cells were developed to modify the tumor microenvironment (TME) to facilitate CAR-T-mediated tumor eradication. Here in the present study, a novel recombinant OAV carrying CCL5, IL12, and IFN-γ controlled by Ki67 promoter was constructed (named AdKi67-C3). The antitumor activity of AdKi67-C3 was tested in vitro and in vivo by using mono administration or combing with CAR-T cells targeting B7H3. It proved that CCL5 expressed by AdKi67-C3 indeed induced more CAR-T migration in vitro and CAR-T infiltration in tumor mass in vivo. Meanwhile, cytokines of IFN-γ and IL12 secreted by AdKi67-C3-infected tumor cells significantly promoted proliferation and persistence of CAR-T cells in vitro and in vivo. In tumor-bearing xenograft mouse models of kidney, prostate or pancreatic cancer, local pretreatment with AdKi67-C3 dramatically enhanced CAR-T cell efficacy and eliminated local and distant tumors. More importantly, mice achieving complete tumor regression resisted to re-challenge with the same tumor cells, suggesting establishment of long-term antitumor immune response. Therefore, OAVs armored with cytokines could be developed as a bioenhancer to defeat the immunosuppressive microenvironment and improve therapeutic efficacy of CAR-T in solid tumors.

Leveraging immune resistance archetypes in solid cancer to inform next-generation anticancer therapies

Anticancer immunotherapies, such as immune checkpoint inhibitors, bispecific antibodies, and chimeric antigen receptor T cells, have improved outcomes for patients with a variety of malignancies. However, most patients either do not initially respond or do not exhibit durable responses due to primary or adaptive/acquired immune resistance mechanisms of the tumor microenvironment. These suppressive programs are myriad, different between patients with ostensibly the same cancer type, and can harness multiple cell types to reinforce their stability. Consequently, the overall benefit of monotherapies remains limited. Cutting-edge technologies now allow for extensive tumor profiling, which can be used to define tumor cell intrinsic and extrinsic pathways of primary and/or acquired immune resistance, herein referred to as features or feature sets of immune resistance to current therapies. We propose that cancers can be characterized by immune resistance archetypes, comprised of five feature sets encompassing known immune resistance mechanisms. Archetypes of resistance may inform new therapeutic strategies that concurrently address multiple cell axes and/or suppressive mechanisms, and clinicians may consequently be able to prioritize targeted therapy combinations for individual patients to improve overall efficacy and outcomes.

IL-12 and IL-27 Promote CD39 Expression on CD8+ T Cells and Differentially Regulate the CD39+CD8+ T Cell Phenotype

Tumor-specific CD8+ T cells are critical components of antitumor immunity; however, factors that modulate their phenotype and function have not been completely elucidated. Cytokines IL-12 and IL-27 have recognized roles in promoting CD8+ T cells' effector function and mediated antitumor responses. Tumor-specific CD8+ tumor-infiltrating lymphocytes (TILs) can be identified based on surface expression of CD39, whereas bystander CD8+ TILs do not express this enzyme. It is currently unclear how and why tumor-specific CD8+ T cells uniquely express CD39. Given the important roles of IL-12 and IL-27 in promoting CD8+ T cell functionality, we investigated whether these cytokines could modulate CD39 expression on these cells. Using in vitro stimulation assays, we identified that murine splenic CD8+ T cells differentially upregulate CD39 in the presence of IL-12 and IL-27. Subsequently, we assessed the exhaustion profile of IL-12- and IL-27-induced CD39+CD8+ T cells. Despite the greatest frequency of exhausted CD39+CD8+ T cells after activation with IL-12, as demonstrated by the coexpression of TIM-3+PD-1+LAG-3+ and reduced degranulation capacity, these cells retained the ability to produce IFN-γ. IL-27-induced CD39+CD8+ T cells expressed PD-1 but did not exhibit a terminally exhausted phenotype. IL-27 was able to attenuate IL-12-mediated inhibitory receptor expression on CD39+CD8+ T cells but did not rescue degranulation ability. Using an immunogenic neuro-2a mouse model, inhibiting IL-12 activity reduced CD39+CD8+ TIL frequency compared with controls without changing the overall CD8+ TIL frequency. These results provide insight into immune regulators of CD39 expression on CD8+ T cells and further highlight the differential impact of CD39-inducing factors on the phenotype and effector functions of CD8+ T cells.

Multifaceted Nano-DEV-IL for Sustained Release of IL-12 to Avert the Immunosuppressive Tumor Microenvironment and IL-12-Associated Toxicities

Interleukin-12 (IL-12) demonstrates potent antitumor activity by enhancing Th1/Th2 response, facilitating cytotoxic T-cell (CTL) recruitment into tumors, inhibiting tumor angiogenesis, and depleting immunosuppressive cells in the tumor microenvironment (TME). Despite having encouraging preclinical and some clinical results, further development of IL-12 is limited because dose-limiting toxicity is observed in early clinical trials with systemic administration of recombinant human IL-12. Hence, strategies aiming to lower the toxicity and to improve response rates are unmet needs. In this study, IL-12 was encapsulated in extracellular vesicles derived from mature dendritic cells (DEVs) activated with tumor antigens. IL-12-encapsulated DEVs (DEV-IL) delayed the growth of murine glioblastoma by facilitating the recruitment of CD8 T-cells, NK-cells, and DCs and effectively depleting immunosuppressive cells in the TME. DEV-IL shifted the Th1/Th2 ratio toward dominating Th1 cytokines which further led to the inhibition of angiogenesis. In addition, DEV-IL also modulated systemic immunity by enhancing CTL activity and the levels of proinflammatory cytokines in the spleen. Interestingly, DEV-IL did not impart hepatic and immunotoxicity which was observed with free IL-12 administration. Hence, our study established DEV-IL as a potent platform for the sustained delivery of cytokines and could be a promising immunotherapeutic strategy for the treatment of cancer.

Immune correlates with response in patients with metastatic solid tumors treated with a tumor targeting immunocytokine NHS-IL12

The immunocytokine NHS-IL12 delivers IL-12 to the tumor microenvironment by targeting DNA/histones in necrotic areas. The first-in-human clinical trial administered NHS-IL12 subcutaneously in 59 patients treated every four weeks (Q4W), with a maximum tolerated dose of 16.8 mcg/kg. The phase I study was expanded to include a high-exposure cohort that received bi-weekly treatment (Q2W) with two dose levels of NHS-IL12: 12.0 mcg/kg and 16.8 mcg/kg. Here, patients given NHS-IL12 were analyzed both prior to and early after treatment for effects on 10 serum soluble analytes, complete blood counts, and 158 peripheral immune subsets. Higher levels of immune activation were seen with a dose of 16.8 mcg/kg versus 12.0 mcg/kg in patients in the high-exposure cohort, as evidenced by greater increases in serum IFNγ, TNFα, and soluble PD-1, and greater increases in frequencies of peripheral ki67+ mature natural killer (NK), CD8+T, and NKT cells. Greater immune activation was also seen in the Q2W versus Q4W cohort, as demonstrated by greater increases in pro-inflammatory serum analytes, ki67+ CD8+ T, NK, and NKT cells, intermediate monocytes, and a greater decrease in CD73+ T cells. Specific immune analytes at baseline including lower levels of monocytes and plasmacytoid dendritic cells, and early changes after treatment such as an increase in refined NK cell subsets and total CD8+ T cells, associated with better clinical response. These findings may help to guide future schedule and dosing regimens of clinical studies of NHS-IL12 as monotherapy and in combination therapies.

Novel strategies to improve efficacy of treatment with tumor-infiltrating lymphocytes (TILs) for patients with solid cancers

PURPOSE OF REVIEW

Treatment with tumor-infiltrating lymphocytes (TILs) has shown remarkable clinical responses in patients with advanced solid tumors. Although the TIL production process is very robust, the original protocol stems from the early nineties and lacks effective selection for tumor-reactivity and functional activity. In this review we highlight the limitations of the current production process and give an overview of improvements that can be made to increase TIL efficacy.

RECENT FINDINGS

With the recent advances in single cell sequencing technologies, our understanding of the composition and phenotype of TILs in the tumor micro environment has majorly increased, which forms the basis for the development of new strategies to improve the TIL production process. Strategies involve selection for neoantigen-reactive TILs by cell sorting or selective expansion strategies. Furthermore, gene editing strategies like Clustered regularly interspaced short palindromic repeats-Cas (CRISPR-Cas9) can be used to increase TIL functionality.

SUMMARY

Although combining all the possible improvements into a next generation TIL product might be challenging, it is highly likely that those techniques will increase the clinical value of TIL therapy in the coming years.

Targeted modulation of immune cells and tissues using engineered biomaterials

Therapies modulating the immune system offer the prospect of treating a wide range of conditions including infectious diseases, cancer and autoimmunity. Biomaterials can promote specific targeting of immune cell subsets in peripheral or lymphoid tissues and modulate the dosage, timing and location of stimulation, thereby improving safety and efficacy of vaccines and immunotherapies. Here we review recent advances in biomaterials-based strategies, focusing on targeting of lymphoid tissues, circulating leukocytes, tissue-resident immune cells and immune cells at disease sites. These approaches can improve the potency and efficacy of immunotherapies by promoting immunity or tolerance against different diseases.

Increased Expression of SRSF1 Predicts Poor Prognosis in Multiple Myeloma

Background

Multiple myeloma (MM) is a clonal plasma cell disorder which still lacks sufficient prognostic factors. The serine/arginine-rich splicing factor (SRSF) family serves as an important splicing regulator in organ development. Among all members, SRSF1 plays an important role in cell proliferation and renewal. However, the role of SRSF1 in MM is still unknown.

Methods

SRSF1 was selected from the primary bioinformatics analysis of SRSF family members, and then we integrated 11 independent datasets and analyzed the relationship between SRSF1 expression and MM clinical characteristics. Gene set enrichment analysis (GSEA) was conducted to explore the potential mechanism of SRSF1 in MM progression. ImmuCellAI was used to estimate the abundance of immune infiltrating cells between the SRSF1^high and SRSF1^low groups. The ESTIMATE algorithm was used to evaluate the tumor microenvironment in MM. The expression of immune-related genes was compared between the groups. Additionally, SRSF1 expression was validated in clinical samples. SRSF1 knockdown was conducted to explore the role of SRSF1 in MM development.

Results

SRSF1 expression showed an increasing trend with the progression of myeloma. Besides, SRSF1 expression increased as the age, ISS stage, 1q21 amplification level, and relapse times increased. MM patients with higher SRSF1 expression had worse clinical features and poorer outcomes. Univariate and multivariate analysis indicated that upregulated SRSF1 expression was an independent poor prognostic factor for MM. Enrichment pathway analysis confirmed that SRSF1 takes part in the myeloma progression via tumor-associated and immune-related pathways. Several checkpoints and immune-activating genes were significantly downregulated in the SRSF1^high groups. Furthermore, we detected that SRSF1 expression was significantly higher in MM patients than that in control donors. SRSF1 knockdown resulted in proliferation arrest in MM cell lines.

Conclusion

The expression value of SRSF1 is positively associated with myeloma progression, and high SRSF1 expression might be a poor prognostic biomarker in MM patients.

Secretory co-factors in next-generation cellular therapies for cancer

Since chimeric antigen receptor (CAR) T-cell therapies for hematologic malignancies were approved by the U.S. Food and Drug Administration, numerous "next-generation" CAR T cells have been developed to improve their safety, efficacy, and applicability. Although some of these novel therapeutic strategies are promising, it remains difficult to apply these therapies to solid tumors and to control adverse effects, such as cytokine release syndrome and neurotoxicity. CAR T cells are generated using highly scalable genetic engineering techniques. One of the major strategies for producing next-generation CAR T cells involves the integration of useful co-factor(s) into the artificial genetic design of the CAR gene, resulting in next-generation CAR T cells that express both CAR and the co-factor(s). Many soluble co-factors have been reported for CAR T cells and their therapeutic effects and toxicity have been tested by systemic injection; therefore, CAR T cells harnessing secretory co-factors could be close to clinical application. Here, we review the various secretory co-factors that have been reported to improve the therapeutic efficacy of CAR T cells and ameliorate adverse events. In addition, we discuss the different co-factor expression systems that have been used to optimize their beneficial effects. Altogether, we demonstrate that combining CAR T cells with secretory co-factors will lead to next-generation CAR T-cell therapies that can be used against broader types of cancers and might provide advanced tools for more complicated synthetic immunotherapies.

Analysis of potential biomarkers of response to IL‐12 therapy

IL‐12 is a proinflammatory cytokine capable of inducing a wide range of effects on both innate and adaptive immune responses. Its stimulatory effects on T cells and NK cells have led to its classification as a potential inducer of antitumor immunity. Clinical trials have been attempting to harness its immune‐stimulating capacity since the 1990s and have had much success despite notable toxicity issues early on. Several methods of IL‐12 delivery have been employed including i.v., s.c., and local administrations as well as plasmid and gene therapies. However, despite differing methods, dosages, and cancer types utilized in these clinical trials, there are still many patients who do not respond to IL‐12 therapy. This creates an opportunity for further investigation into the immunologic differences between responding and nonresponding patients in order to better understand the variable efficacy of IL‐12 therapy. This review focuses on a limited collection of IL‐12 clinical trials, which further analyzed these individual subsets and detected biologic variables correlating with differential patient responses. A comprehensive review of these potential biomarkers identified 7 analytes that correlated with beneficial patient responses in 3 or more clinical trials. These were increased levels of IFN‐γ, IP‐10, TNF‐α, MIP‐1α, MIG, and CD4⁺ and CD8⁺ T cells, with a decrease in VEGF, bFGF, FoxP3⁺ T regulatory cells, and M2 macrophages. These potential biomarkers highlight the possibility of identifying immunologic determinants of patient response to IL‐12 therapy to conserve valuable resources and benefit patients.

Human Papillomavirus-Directed Therapeutics for Human Papillomavirus-Associated Oropharyngeal Cancer

ABSTRACT

Despite the availability of prophylactic human papillomavirus (HPV) vaccines, there is a growing incidence of HPV-associated head and neck squamous cell carcinomas (HPV-HNSCC) worldwide. The viral etiology of HPV-HNSCC provides an opportunity to develop personalized immune-based therapies, which target the unique viral- or tumor-specific proteins. Novel HPV-targeted immunotherapeutic approaches in clinical development are reviewed. Early results from these trials highlight new opportunities and potential challenges ahead. Immunotherapies for HPV-associated HNSCCs will require a tailored combinatorial approach based on preexisting mechanisms of host immune resistance. As the field continues to identify the relevant HPV types 16 and 18 immunogenic epitopes that are presented by diverse HLA class I alleles, improved HPV-targeted biologics and clinical monitoring tools can be developed and applied to a broader cancer patient population.