Traditional CAR-T treatments, while successful in some blood cancer cases, have faced limitations due to their complexity, expense, and time-consuming nature. The Johns Hopkins team’s innovative approach circumvents this by delivering a nanotechnological payload that automatically activates and modifies T cells—the warriors of the immune system—in vivo. This breakthrough has the potential to democratize access to life-saving immunotherapies and dramatically streamline treatment protocols, reducing barriers posed by existing methodologies.

The core of these nanoparticles is formed from biodegradable polymers composed of ester units, which safely degrade within aqueous environments such as the bloodstream. The surface of each nanoparticle is meticulously functionalized with two antibodies: antiCD3 and antiCD28. These critical molecules serve as homing devices, enabling the nanoparticles to precisely locate and bind to T cells scattered throughout the blood and lymphoid tissues. Upon engagement, the nanoparticles not only stimulate T cell activation but also facilitate internalization, which is pivotal for subsequent genetic reprogramming.

Encased within the molecular shell of these “ship-like” nanoparticles lies messenger RNA (mRNA) – a transient genetic blueprint that instructs T cells to express receptors specifically designed to detect and eliminate B cells that contribute to diseases like lupus, leukemia, and lymphoma. By delivering mRNA payloads directly inside T cells, the nanoparticles roundly bypass the challenges of cellular engineering outside the body, enabling an internal transformation of immune cells into potent, disease-targeting agents.

In rigorous preclinical trials involving healthy murine models, a single injection of these nanoparticles resulted in a staggering 95% reduction of circulating B cells within just 24 hours. Furthermore, approximately half of the B cells residing in the spleen were depleted, showcasing the nanoparticles’ systemic reach and effective targeting capabilities. Remarkably, even after a week, blood B cells remained suppressed at about 50% of their original levels, illustrating a potent yet controlled immune modulation.

The stepwise operational mechanism of these nanoparticles is as ingenious as it is elegant. Comparable to multi-stage rockets designed for outer space missions, these engineered carriers embark on an “inner space” voyage, first engaging and activating target T cells, then penetrating cellular membranes, and finally degrading to unleash mRNA cargoes. This programmed release not only ensures successful mRNA transfer but also prevents unintended degradation, an obstacle that commonly hinders intracellular delivery vehicles.

Delivering genetic material specifically to T cells presents unique challenges, as these cells possess intrinsic defenses to resist uptake and neutralize foreign particles—a feature evolved to prevent viral hijacking such as seen in HIV infections. The Johns Hopkins team overcame this biological defense by optimizing nanoparticle composition and surface chemistry, achieving approximately a 10% success rate of mRNA escape from intracellular degradation compartments inside T cells, which is substantially higher than the 1% to 2% efficiency observed with many other nanoparticle platforms.

The engineered nanoparticles were benchmarked against commercially available magnetic beads traditionally used for T cell stimulation in laboratory settings. Results demonstrated equivalent efficacy in T cell activation levels, but with the significant advantage that the nanoparticles advanced one step further by penetrating the cells to initiate genetic reprogramming. This dual functionality underscores the therapeutic promise of the technology, enabling both priming and modification of immune cells in a seamless process.

This pioneering research signifies a convergence of immunology and biomedical engineering disciplines at Johns Hopkins. By fusing knowledge from artificial immune cell development and polymer-based nanocarriers, the team has fashioned a streamlined immunotherapeutic tool with scalable manufacturing potential. Their goal is to expand this platform to refine targeting specificity, modulate the intensity of immune stimulation, and eventually translate it into human clinical applications for diseases driven by pathogenic B cells.

In recognition of its transformative potential, this research collaboration has secured over $40 million in funding from the Advanced Research Projects Agency for Health (ARPA-H), enabling continued innovation and development of next-generation cellular engineering technologies. The funding will support fine-tuning of the nanoparticles, ensuring safety, efficacy, and versatility across a range of immune-related disorders.

As these biodegradable nanoparticles advance toward clinical trials, they hold the promise to revolutionize immunotherapy by providing an off-the-shelf, highly adaptable treatment modality. This approach could significantly reduce the financial and temporal burdens associated with conventional CAR-T therapies, while expanding patient access globally. By harnessing the immune system’s intrinsic power to heal from within, this technology represents a paradigm shift toward more precise, efficient, and personalized medicine.

In summary, Johns Hopkins’ innovative nanoparticle platform has successfully demonstrated in vivo engineering of immune T cells, leading to rapid and substantial depletion of disease-associated B cells. The modularity and simplicity of the design, combined with its intracellular delivery success, mark a vital step forward in immunotherapeutic technology. As the research continues to evolve, it offers hope for safer, more accessible treatments for autoimmune diseases and hematologic cancers, redefining the landscape of future immune-based interventions.

Subject of Research: Engineering Immune T Cells In Vivo Using Biodegradable Nanoparticles for Targeted Depletion of Pathogenic B Cells in Autoimmune Diseases and Blood Cancers

Article Title: Simplified Biodegradable Nanoparticles for In Vivo Engineering of T Cells to Target Autoimmune and Hematologic Diseases

News Publication Date: March 11, 2024

Web References: https://www.science.org/doi/10.1126/sciadv.adz1722

References: DOI: 10.1126/sciadv.adz1722

Image Credits: Manav Jain and Jordan Green, Johns Hopkins Medicine

Keywords

Nanoparticles, Immunotherapy, CAR-T cells, mRNA delivery, Biodegradable polymers, T cell engineering, Autoimmune diseases, Blood cancers, In vivo gene therapy, Immune modulation, Johns Hopkins Medicine, Nanomedicine

The investigators conducted rigorous in vivo experiments involving immunodeficient NSG mice engineered to develop human B cell leukemia via injection of luciferase-expressing NALM6 cells. This model allowed real-time tracking of leukemic burden through bioluminescence imaging, providing quantifiable metrics of therapeutic response. Reducing the CAR T cell dosing to a deliberately suboptimal 0.6 million cells further tested the robustness of gene knockout strategies under challenging conditions.

Among the top-performing targets, knockout of the RHOG gene emerged as particularly potent. RHOG-knockout CAR T cells demonstrated superior leukemia clearance and strikingly prolonged survival in treated mice compared to standard CAR T cells. These findings were consistent across multiple donor-derived CAR T cell products, underlining the robustness and reproducibility of the approach. RHOG, a small GTPase implicated in cytoskeletal dynamics and cell migration, appears to exert a profound influence on T cell function when ablated.

The study also revisited PRDM1 knockout, previously reported to enhance initial tumor clearance. Although PRDM1-knockout CAR T cells facilitated rapid initial reduction of leukemic cells, they failed to sustain long-term remission or delay relapse effectively. This contrasts with RHOG knockout, which conferred durable responses and significant survival advantages, emphasizing the need for in vivo validation beyond early responses.

In parallel, the team evaluated FAS knockout, leveraging top guides selected from comprehensive CRISPR screens and utilizing ribonucleoprotein electroporation for gene editing. FAS-knockout CAR T cells outperformed their unedited counterparts, aligning with prior studies that underscored the role of FAS-FAS ligand signaling in modulating CAR T cell persistence. This knockout is undergoing clinical evaluation in ovarian cancer trials, reflecting its translational potential.

Remarkably, the dual knockout of RHOG and FAS produced synergistic effects, with markedly improved leukemic clearance and survival outcomes surpassing those of either single knockout alone. This combinatorial approach resulted in curative efficacy in some treated mice within an otherwise fatal leukemia model. Importantly, relapsed leukemias retained CD19 expression, indicating that antigen loss was not a mechanism of therapeutic failure in these experiments.

The safety profile of CRISPR-enhanced CAR T cells was also addressed through extended observation periods up to over a year post-infusion, revealing no evidence of malignant transformation or adverse events attributable to gene editing. Such long-term safety data are crucial for the clinical translation of genome-edited cellular therapies and have been a critical regulatory concern.

Beyond B cell malignancies, RHOG knockout consistently bolstered CAR T cell expansion in vitro and improved tumor clearance across diverse CAR constructs targeting different antigens, including GD2 and GPC3, and associated signaling domains (19-BBz, 19-28z, and GD2-BBz). This broad applicability underscores RHOG’s central role in T cell biology and its potential as a universal enhancer of CAR T cell efficacy.

Furthermore, the combination of RHOG and FAS knockouts enhanced anti-tumor activity in a solid tumor model involving Huh7 cancer cells, showcasing the feasibility of this gene editing strategy beyond hematologic cancers. Overcoming the challenges of solid tumor immunotherapy remains a major frontier, and these results offer promising avenues for intervention.

Central memory T cell populations (CD45RO+CD62L+) increased among RHOG-knockout CAR T cells following repeated antigen stimulation in vitro, suggesting improved T cell persistence and functionality. These attributes are often correlated with enhanced clinical efficacy in adoptive cell therapies, highlighting mechanistic insights into how RHOG knockout confers therapeutic advantage.

The in vivo expansion of both CD4+ and CD8+ CAR T cells was significantly augmented following RHOG knockout, confirming improved cellular proliferation or survival post-infusion. Notably, exhaustion marker expression (PD-1, LAG3, TIM3, TIGIT) on RHOG-knockout CAR T cells was not significantly different from standard CAR T cells, indicating that enhanced expansion was not due to reduced exhaustion but likely other intrinsic functional improvements.

This landmark study systematically establishes RHOG knockout, alone or in combination with FAS knockout, as a powerful CRISPR-boosted strategy to enhance CAR T cell immunotherapy. The meticulous validation across multiple models, dosages, CAR designs, and tumor types enhances confidence that these modifications could translate into substantial clinical benefit.

By providing comprehensive mechanistic insights alongside rigorous preclinical validation, this research opens new paths to potentially overcoming the current limitations of CAR T cell therapies. As gene editing technologies advance and regulatory pathways evolve, such sophisticated combinatorial knockout strategies may soon enter clinical trials, offering hope for more durable and effective cancer immunotherapies.

The convergence of CRISPR gene editing with adoptive cell therapy exemplifies the future of precision immuno-oncology, where the immune system’s power can be fine-tuned at the genomic level to maximize therapeutic impact. Continued exploration of additional gene targets and synergistic combinations will likely further refine this therapeutic platform, ultimately aiming to deliver more reliable cures for diverse malignancies.

Subject of Research:
Systematic identification and validation of gene knockouts to enhance the efficacy of chimeric antigen receptor (CAR) T cell immunotherapies using CRISPR technology.

Article Title:
Systematic discovery of CRISPR-boosted CAR T cell immunotherapies.

Article References:
Datlinger, P., Pankevich, E.V., Arnold, C.D. et al. Systematic discovery of CRISPR-boosted CAR T cell immunotherapies. Nature (2025). https://doi.org/10.1038/s41586-025-09507-9

At its core, CAR-T cell therapy involves isolating the patient’s own T lymphocytes, genetically engineering them to express receptors that specifically identify and bind to cancer cells, and then reinfusing these modified cells back into the patient’s bloodstream. These engineered cells are uniquely equipped to seek out and destroy malignant cells expressing the targeted antigen, which in many cases is CD19, a molecule present on the surface of B cells. However, refractory patients often relapse due to a complex interplay of immunosuppressive tumor microenvironments and intrinsic cellular resistances, limiting the efficacy and persistence of CAR-T cells.

Recently, Brazilian scientists from the A.C.Camargo Cancer Center, supported by the São Paulo Research Foundation (FAPESP), have unveiled a promising advancement aimed at bolstering the cytotoxic capacity of CAR-T cells. Their study, published in the prestigious journal Cancer Research, explores the modulation of epigenetic regulators to amplify the functional potency of these immunotherapeutic agents. Specifically, they targeted the Polycomb Repressive Complex 2 (PRC2), a critical epigenetic modulator that governs gene expression by methylating histone proteins, thereby influencing chromatin structure and silencing genes.

PRC2’s physiological role encompasses maintaining immune homeostasis by silencing genes that could otherwise trigger excessive immune activation and potentially autoimmunity. In the context of cancer, however, these ‘brakes’ imposed by PRC2 on T cells can be detrimental, blunting the full cytotoxic potential necessary to eradicate tumor cells completely. While CAR-T therapy conceptually removes inhibitory checkpoints to enhance cell activity, residual epigenetic repression by complexes like PRC2 remains an obstacle to achieving robust and sustained anti-neoplastic responses.

The researchers hypothesized that pharmacological inhibition of PRC2 during CAR-T cell manufacturing could alleviate these epigenetic constraints, thereby unleashing a more vigorous antitumor effect. To test this, they procured peripheral blood mononuclear cells from both healthy donors and patients diagnosed with either non-Hodgkin’s lymphoma or acute lymphoblastic leukemia. These cells were engineered to produce CAR-T cells, which were then treated with a specific PRC2 inhibitor before being deployed against tumor cells in vitro.

Results from these experiments demonstrated that PRC2-inhibited CAR-T cells exhibited markedly enhanced cytotoxicity, characterized by accelerated tumor cell lysis and improved persistence compared to their conventional counterparts. This effect was attributed to epigenetic reprogramming, which presumably upregulated genes integral to T-cell effector functions while reducing the expression of inhibitory molecules. Notably, the enhanced CAR-T cells maintained selective targeting of malignant cells, suggesting that PRC2 inhibition fine-tunes immune responses without broadly compromising specificity.

To translate these findings beyond cellular cultures, the team advanced to in vivo models, implanting mice with tumors representative of the two challenging hematological cancers. After administering the modified CAR-T cells – carefully washed to remove residual inhibitor and prevent systemic toxicity – the animals exhibited pronounced tumor regression and prolonged survival relative to controls treated with standard CAR-T cells. The researchers emphasize that the washing step was critical to mitigate off-target effects and the risk of systemic immunosuppression, considering PRC2’s broad biological functions.

Epigenetic modulation of CAR-T cells heralds a paradigm shift in how immunotherapies can be optimized. Traditionally, focus has centered on genetic modifications and checkpoint blockade; however, this study highlights that fine-tuning the chromatin landscape to unlock latent transcriptional programs is a powerful complementary strategy. The enhanced durability and potency of PRC2-inhibited CAR-T cells could pave the way for improved clinical outcomes, particularly in patient subgroups historically resistant to existing modalities.

Looking ahead, the scientists plan rigorous evaluations of safety and potential side effects, given that immunotherapies often exacerbate inflammatory responses which, if uncontrolled, can lead to cytokine release syndrome or neurotoxicity. Their preliminary approach of removing the PRC2 inhibitor prior to infusion is designed to circumvent such systemic issues. Nevertheless, exhaustive preclinical toxicology studies are essential before human trials can commence.

This innovative research not only charts a novel course for CAR-T cell augmentation but also exemplifies the importance of interdisciplinary collaboration, integrating insights from immunology, epigenetics, and oncology. The work has been generously supported by doctoral and post-doctoral grants from FAPESP, reflecting a commitment to nurturing scientific talent and advancing translational medicine within Brazil and globally.

In conclusion, the strategic targeting of epigenetic machinery like PRC2 represents a transformative advance in CAR-T therapy for hematological malignancies. By overcoming intrinsic cellular restraints, this approach holds significant promise to elevate patient responses, reduce relapse rates, and ultimately shift the prognosis for those affected by non-Hodgkin’s lymphoma and acute lymphoblastic leukemia. As this research progresses toward clinical testing, the oncology community eagerly anticipates a new frontier where CAR-T cells are not only engineered genetically but also epigenetically empowered to deliver superior therapeutic benefit.

Subject of Research:
Epigenetic enhancement of CAR-T cell immunotherapy targeting hematological malignancies through PRC2 inhibition.

Article Title:
Targeting PRC2 Enhances the Cytotoxic Capacity of Anti-CD19 CAR-T Cells Against Hematological Malignancies

News Publication Date:
19-Feb-2025

Web References:
http://dx.doi.org/10.1158/0008-5472.CAN-24-1643

References:
Published study in Cancer Research journal, DOI: 10.1158/0008-5472.CAN-24-1643

Keywords:
Cancer immunotherapy, Blood cells, Leukemia, Cytotoxicity

CAR T cell therapy has emerged as one of the most significant advances in the treatment of blood cancers, providing hope for many patients whose disease has not responded to conventional therapies. However, a concerning reality is that more than half of NHL patients who do not respond favorably to initial treatments end up relapsing or progressing shortly after receiving CAR T therapy. This high rate of treatment failure has underscored the need for advanced predictive tools that can identify which patients are most likely to benefit from such innovative therapies.

The researchers behind InflaMix have utilized machine learning methodologies to analyze the profiles of inflammation in the blood of 149 NHL patients. The significance of this tool lies in its ability to assess various blood biomarkers related to inflammation, which has been implicated as a contributing factor to CAR T therapy failure. Traditional clinical practices have not typically employed these biomarkers, which InflaMix has now identified as critical in forecasting treatment outcomes.

The model operates on an unsupervised basis, meaning that it was trained without any prior knowledge of patient outcomes. By detecting an inflammatory biomarker through a set of unique blood tests, InflaMix can illuminate the inflammatory signatures associated with a heightened risk of CAR T treatment failure, encompassing risks of disease relapse as well as increased mortality. This novel approach allows for a more nuanced understanding of the biological mechanisms at play during CAR T therapy.

Dr. Marcel van den Brink, one of the leading authors of the study and a prominent figure at City of Hope, expressed optimism about the potential of InflaMix. He emphasized that this tool could serve as a universal asset for oncologists everywhere, enabling them to evaluate the risks associated with CAR T therapy on an individual basis, ultimately leading to a more personalized treatment journey for each patient. This ability to tailor treatment strategies based on empirical evidence could revolutionize how oncologists approach CAR T therapy and similar innovative treatments.

Furthermore, the impressiveness of InflaMix is accentuated by its flexibility. The model performed well even when evaluated with only six commonly used blood tests, all of which are typically assessed in lymphoma patients. This flexibility signifies that the test could be broadly accessible, making it feasible for most NHL patients to benefit from its predictive capabilities, regardless of their specific clinical background or treatment history.

Oncologist Dr. Sandeep Raj, who led the study at MSK, affirmed that prior studies had hinted at inflammation being a risk factor for diminishing the efficacy of CAR T cell therapies. The team’s endeavor to refine this understanding and create a robust clinical tool has culminated in the development of InflaMix, which not only characterizes inflammation in blood but also predicts the likelihood of successful CAR T therapy outcomes among patients.

Validation of the model was established through studies that included three independent cohorts comprising 688 NHL patients. This diversified group exhibited various clinical characteristics and disease subtypes while having received different CAR T products. The array of clinical data reinforces the reliability of the InflaMix tool in diverse patient profiles, enhancing its utility as a standard part of clinical assessments.

Looking forward, researchers at City of Hope and MSK are poised to investigate further the relationship between the blood inflammation patterns identified by InflaMix and their impact on CAR T cell function. By exploring the underlying sources of this inflammation, the team aims to deepen the understanding of factors that influence treatment efficacy in NHL patients treated with CAR T therapy.

The potential applications for InflaMix extend beyond mere prediction. By effectively identifying patients with a high risk of treatment failure, there is an opportunity for clinicians to modify treatment plans. This could involve designing new clinical trials that integrate additional therapeutic strategies aimed at improving CAR T effectiveness—a prospect that holds promise for transforming the landscape of blood cancer treatment.

Currently, City of Hope stands as a leader in CAR T cell therapies, having treated over 1,700 patients since launching their CAR T program in the late 1990s. Their commitment to clinical excellence is reflected in their expansive array of ongoing clinical trials, including 70 studies focused on immune cell products, primarily CAR T therapies, that address various forms of blood and solid tumor cancers. Their efforts not only elevate patient care but also contribute to the overall advancement of cancer research.

Support for the team’s studies has stemmed from notable institutions, including the National Institutes of Health and the National Cancer Institute. With Dr. Van den Brink’s recent transition to City of Hope after two decades at MSK, the collaboration promises to yield innovative discoveries and further establish the institution’s role as a pioneer in CAR T cell therapy research and treatment.

As the cancer research community anticipates the broader implications of this work, InflaMix stands as a beacon of hope for NHL patients and a testament to the potential of integrating advanced technologies like machine learning in clinical settings. The move towards personalized medicine, guided by precise predictors of treatment outcomes, heralds a new era in the fight against cancer, making strides in the quest for more effective and individualized care.

Subject of Research: Machine Learning Tool for Predicting Response to CAR T Cell Therapy in Non-Hodgkin Lymphoma Patients
Article Title: InflaMix: A Machine Learning Approach to Predict CAR T Cell Therapy Outcomes
News Publication Date: 1-Apr-2025
Web References: City of Hope, Nature Medicine
References: NIH, NCI
Image Credits: City of Hope
Keywords: CAR T Cell Therapy, Non-Hodgkin Lymphoma, Machine Learning, InflaMix, Inflammation Biomarkers, Predictive Analytics, Personalized Medicine, Oncology Research, Blood Cancer Treatment, Clinical Trials.