Antigen-dependent IL-12 signaling in CAR T cells promotes regional to systemic disease targeting

Regional and intratumoral adoptive T-cell therapy

Adoptive T-cell therapies (ACTs) including tumor-infiltrating lymphocytes and engineered T cells (transgenic T-cell receptor and chimeric antigen receptor T cells), have made an important impact in the field of cancer treatment over the past years. Most of these therapies are typically administered systemically in approaches that facilitate the elimination of hematologic malignancies. Therapeutical efficacy against solid tumors, however, with the exception of tumor-infiltrating lymphocytes against melanoma, remains limited due to several barriers preventing lymphocyte access to the tumor bed. Building upon the experience of regional administration in other immunotherapies, the regional administration of adoptive cell therapies is being assessed to overcome this challenge, granting a first round of access of the transferred T cells to the tumor niche and thereby ensuring their activation and expansion. Intralesional and intracavitary routes of delivery have been tested with promising antitumor objective responses in preclinical and clinical studies. Additionally, several strategies are being developed to further improve T-cell activity after reinfusing them back to the patient such as combinations with other immunotherapy agents or direct engineering of the transferred T cells, achieving long-term immune memory. Clinical trials testing different regional adoptive T-cell therapies are ongoing but some issues related to methodology of administration and correct selection of the target antigen to avoid on-target/off-tumor side-effects need to be further evaluated and improved. Herein, we discuss the current preclinical and clinical landscape of intratumoral and locoregional delivery of adoptive T-cell therapies.

Multi-armored allogeneic MUC1 CAR T cells enhance efficacy and safety in triple-negative breast cancer

Solid tumors, such as triple-negative breast cancer (TNBC), are biologically complex due to cellular heterogeneity, lack of tumor-specific antigens, and an immunosuppressive tumor microenvironment (TME). These challenges restrain chimeric antigen receptor (CAR) T cell efficacy, underlining the importance of armoring. In solid cancers, a localized tumor mass allows alternative administration routes, such as intratumoral delivery with the potential to improve efficacy and safety but may compromise metastatic-site treatment. Using a multi-layered CAR T cell engineering strategy that allowed a synergy between attributes, we show enhanced cytotoxic activity of MUC1 CAR T cells armored with PD1KO, tumor-specific interleukin-12 release, and TGFBR2KO attributes catered towards the TNBC TME. Intratumoral treatment effectively reduced distant tumors, suggesting retention of antigen-recognition benefits at metastatic sites. Overall, we provide preclinical evidence of armored non-alloreactive MUC1 CAR T cells greatly reducing high TNBC tumor burden in a TGFB1- and PD-L1-rich TME both at local and distant sites while preserving safety.

Building a novel TRUCK by harnessing the endogenous IFN-gamma promoter for cytokine expression

Despite the remarkable success of chimeric antigen receptor (CAR) T therapy in hematological malignancies, its efficacy in solid tumors remains limited. Cytokine-engineered CAR T cells offer a promising avenue, yet their clinical translation is hindered by the risks associated with constitutive cytokine expression. In this proof-of-concept study, we leverage the endogenous interferon (IFN)-γ promoter for transgenic interleukin (IL)-15 expression. We demonstrate that IFN-γ expression is tightly regulated by T cell receptor signaling. By introducing an internal ribosome entry site IL15 into the 3' UTR of the IFN-γ gene via homology directed repair-mediated knock-in, we confirm that IL-15 expression can co-express with IFN-γ in an antigen stimulation-dependent manner. Importantly, the insertion of transgenes does not compromise endogenous IFN-γ expression. In vitro and in vivo data demonstrate that IL-15 driven by the IFN-γ promoter dramatically improves CAR T cells' antitumor activity, suggesting the effectiveness of IL-15 expression. Last, as a part of our efforts toward clinical translation, we have developed an innovative two-gene knock-in approach. This approach enables the simultaneous integration of CAR and IL-15 genes into TRAC and IFN-γ gene loci using a single AAV vector. CAR T cells engineered to express IL-15 using this approach demonstrate enhanced antitumor efficacy. Overall, our study underscores the feasibility of utilizing endogenous promoters for transgenic cytokines expression in CAR T cells.

CAR-T therapy for ovarian cancer: Recent advances and future directions

Ovarian cancer (OC) is a common gynecological tumor with high mortality, which is difficult to control its progression with conventional treatments and is prone to recurrence. Recent studies have identified OC as an immunogenic tumor that can be recognized by the host immune system. Immunotherapy for OC is being evaluated, but approaches such as immune checkpoint inhibitors have limited efficacy, adoptive cell therapy is an alternative therapy, in which CAR(chimeric antigen receptor)-T therapy has been applied to the clinical treatment of hematological malignancies. In addition, CAR-NK and CAR-macrophage (CAR-M) have also shown great potential in the treatment of solid tumors. Here, we discuss recent advances in preclinical and clinical studies of CAR-T for OC treatment, introduce the efforts made by researchers to modify the structure of CAR in order to achieve effective OC immunotherapy, as well as the research status of CAR-NK and CAR-M, and highlight emerging therapeutic opportunities that can be utilized to improve the survival of patients with OC using CAR-based adoptive cell therapy.

Future perspectives on engineered T cells for cancer

Chimeric antigen receptor (CAR) T cell therapy has emerged as a revolutionary treatment for hematological malignancies, but its adaptation to solid tumors is impeded by multiple challenges, particularly T cell dysfunction and exhaustion. The heterogeneity and inhospitableness of the solid tumor microenvironment (TME) contribute to diminished CAR T cell efficacy exhibited by reduced cytotoxicity, proliferation, cytokine secretion, and the upregulation of inhibitory receptors, similar to the phenotype of tumor-infiltrating lymphocytes (TILs). In this review, we highlight recent advances in T cell therapy for solid tumors, particularly brain cancer. Innovative strategies, including locoregional delivery and 'armoring' CAR T cells with cytokines such as interleukin (IL)-18, are under investigation to improve efficacy and safety. We also highlight emerging issues with toxicity management of CAR T cell adverse events. This review discusses the obstacles associated with CAR T cell therapy in the context of solid tumors and outlines current and future strategies to overcome these challenges.

Current and future immunotherapeutic approaches in pancreatic cancer treatment

Pancreatic cancer is a major cause of cancer-related death, but despondently, the outlook and prognosis for this resistant type of tumor have remained grim for a long time. Currently, it is extremely challenging to prevent or detect it early enough for effective treatment because patients rarely exhibit symptoms and there are no reliable indicators for detection. Most patients have advanced or spreading cancer that is difficult to treat, and treatments like chemotherapy and radiotherapy can only slightly prolong their life by a few months. Immunotherapy has revolutionized the treatment of pancreatic cancer, yet its effectiveness is limited by the tumor's immunosuppressive and hard-to-reach microenvironment. First, this article explains the immunosuppressive microenvironment of pancreatic cancer and highlights a wide range of immunotherapy options, including therapies involving oncolytic viruses, modified T cells (T-cell receptor [TCR]-engineered and chimeric antigen receptor [CAR] T-cell therapy), CAR natural killer cell therapy, cytokine-induced killer cells, immune checkpoint inhibitors, immunomodulators, cancer vaccines, and strategies targeting myeloid cells in the context of contemporary knowledge and future trends. Lastly, it discusses the main challenges ahead of pancreatic cancer immunotherapy.

DMPK perspective on quantitative model analysis for chimeric antigen receptor cell therapy: Advances and challenges

Chimeric antigen receptor (CAR) cells are genetically engineered immune cells that specifically target tumor-associated antigens and have revolutionized cancer treatment, particularly in hematological malignancies, with ongoing investigations into their potential applications in solid tumors. This review provides a comprehensive overview of the current status and challenges in drug metabolism and pharmacokinetics (DMPK) for CAR cell therapy, specifically emphasizing on quantitative modeling and simulation (M&S). Furthermore, the recent advances in quantitative model analysis have been reviewed, ranging from clinical data characterization to mechanism-based modeling that connects in vitro and in vivo nonclinical and clinical study data. Additionally, the future perspectives and areas for improvement in CAR cell therapy translation have been reviewed. This includes using formulation quality considerations, characterization of appropriate animal models, refinement of in vitro models for bottom-up approaches, and enhancement of quantitative bioanalytical methodology. Addressing these challenges within a DMPK framework is pivotal in facilitating the translation of CAR cell therapy, ultimately enhancing the patients' lives through efficient CAR cell therapies.

The safety and efficacy of systemic delivery of a new liver-de-targeted TGFβ signaling inhibiting adenovirus in an immunocompetent triple negative mouse mammary tumor model

Aberrant TGFβ signaling is linked to metastasis and tumor immune escape of many cancers including metastatic triple negative breast cancer (mTNBC). Previously, we have found that oncolytic adenoviruses expressing a TGFβ signaling inhibitory protein (sTGFβRIIFc) induced immune activation in a mouse TNBC (4T1) immunocompetent subcutaneous model with intratumoral injection. Systemic administration of adenoviruses can be a superior route to treat mTNBC but faces the challenges of increased toxicity and viral clearance. Thus, we created a liver-de-targeted sTGFβRIIFc- and LyP-1 peptide-expressing adenovirus (mHAdLyp.sT) with enhanced breast cancer cell tropism. Its safety and immune response features were profiled in the 4T1 model. Our data showed that the systemic administration of mHAdLyp.sT resulted in reduced hepatic and systemic toxicity. mHAdLyp.sT was also effective in increasing Th1 cytokines and anti-tumor cell populations by cytokine analysis, spleen/tumor qRT-PCR, and flow cytometry. We further tested the therapeutic effects of mHAdLyp.sT alone and in combination with immune checkpoint inhibitors (ICIs). mHAdLyp.sT alone and with all ICI combinations elicited significant inhibition of lung metastasis by histological analysis. When mHAdLyp.sT was combined with both anti-PD-1 and anti-CTLA-4 antibodies, primary 4T1 tumor growth was also significantly inhibited. We are confident in advancing this new treatment option for mTNBC.

Preclinical and clinical studies of a tumor targeting IL-12 immunocytokine

The clinical success of immune checkpoint inhibitors (ICIs) has demonstrated the promise and challenges of cancer immunotherapy. There is an unmet need to develop novel cancer therapies that can provide clinical benefit for most patients with solid malignancies, which harbor innate or acquired resistance to ICIs. Interleukin-12 (IL-12) is a promising cytokine for cancer therapy given its direct stimulatory effects on innate and adaptive immunity. However, unfavorable pharmacokinetics and a narrow therapeutic index render recombinant IL-12 (rIL-12) less attractive as a cancer therapy. NHS-IL12 is a fusion protein of IL-12 and NHS76 (human IgG1) antibody engineered to target single and double stranded DNA present in necrotic areas solid tumors. In preclinical tumor models, NHS-IL12 elicited significant Th1 immune activation and tumor suppressive effects, primarily mediated by NK and CD8+ T lymphocytes, with engagement of myeloid immunity. NHS-IL12 is currently being evaluated clinically in combination with various therapeutic modalities, including chemotherapy, radiation therapy, immune checkpoint inhibition, vaccines, and epigenetic modulation. Here we review the preclinical and clinical studies involving NHS-IL12 for the treatment of solid malignancies.

New insights into the stemness of adoptively transferred T cells by γc family cytokines

T cell-based adoptive cell therapy (ACT) has exhibited excellent antitumoral efficacy exemplified by the clinical breakthrough of chimeric antigen receptor therapy (CAR-T) in hematologic malignancies. It relies on the pool of functional T cells to retain the developmental potential to serially kill targeted cells. However, failure in the continuous supply and persistence of functional T cells has been recognized as a critical barrier to sustainable responses. Conferring stemness on infused T cells, yielding stem cell-like memory T cells (TSCM) characterized by constant self-renewal and multilineage differentiation similar to pluripotent stem cells, is indeed necessary and promising for enhancing T cell function and sustaining antitumor immunity. Therefore, it is crucial to identify TSCM cell induction regulators and acquire more TSCM cells as resource cells during production and after infusion to improve antitumoral efficacy. Recently, four common cytokine receptor γ chain (γc) family cytokines, encompassing interleukin-2 (IL-2), IL-7, IL-15, and IL-21, have been widely used in the development of long-lived adoptively transferred TSCM in vitro. However, challenges, including their non-specific toxicities and off-target effects, have led to substantial efforts for the development of engineered versions to unleash their full potential in the induction and maintenance of T cell stemness in ACT. In this review, we summarize the roles of the four γc family cytokines in the orchestration of adoptively transferred T cell stemness, introduce their engineered versions that modulate TSCM cell formation and demonstrate the potential of their various combinations. Video Abstract.