Regional CAR-T cell infusions for peritoneal carcinomatosis are superior to systemic delivery

Infusion and delivery strategies to maximize the efficacy of CAR-T cell immunotherapy for cancers

Chimeric antigen receptor (CAR) T-cell therapy has achieved substantial clinical outcomes for tumors, especially for hematological malignancies. However, extending the duration of remission, reduction of relapse for hematological malignancies and improvement of the anti-tumor efficacy for solid tumors are challenges for CAR-T cells immunotherapy. Besides the endeavors to enhance the functionality of CAR-T cell per se, optimization of the infusion and delivery strategies facilitates the breakthrough of the hurdles that limited the efficacy of this cancer immunotherapy. Here, we summarized the infusion and delivery strategies of CAR-T cell therapies under pre-clinical study, clinical trials and on-market status, through which the improvements of safety and efficacy for hematological and solid tumors were analyzed. Of note, novel infusion and delivery strategies, including local-regional infusion, biomaterials bearing the CAR-T cells and multiple infusion technique, overcome many limitations of CAR-T cell therapy. This review provides hints to determine infusion and delivery strategies of CAR-T cell cancer immunotherapy to maximize clinical benefits.

Contemporary Approaches to Immunotherapy of Solid Tumors

In recent years, the arrival of the immunotherapy industry has introduced the possibility of providing transformative, durable, and potentially curative outcomes for various forms of malignancies. However, further research has shown that there are a number of issues that significantly reduce the effectiveness of immunotherapy, especially in solid tumors. First of all, these problems are related to the protective mechanisms of the tumor and its microenvironment. Currently, major efforts are focused on overcoming protective mechanisms by using different adoptive cell therapy variants and modifications of genetically engineered constructs. In addition, a complex workforce is required to develop and implement these treatments. To overcome these significant challenges, innovative strategies and approaches are necessary to engineer more powerful variations of immunotherapy with improved antitumor activity and decreased toxicity. In this review, we discuss recent innovations in immunotherapy aimed at improving clinical efficacy in solid tumors, as well as strategies to overcome the limitations of various immunotherapies.

Recent advances in targeted drug delivery for the treatment of glioblastoma

Glioblastoma multiforme (GBM) is one of the highly malignant brain tumors characterized by significant morbidity and mortality. Despite the recent advancements in the treatment of GBM, major challenges persist in achieving controlled drug delivery to tumors. The management of GBM poses considerable difficulties primarily due to unresolved issues in the blood-brain barrier (BBB)/blood-brain tumor barrier (BBTB) and GBM microenvironment. These factors limit the uptake of anti-cancer drugs by the tumor, thus limiting the therapeutic options. Current breakthroughs in nanotechnology provide new prospects concerning unconventional drug delivery approaches for GBM treatment. Specifically, swimming nanorobots show great potential in active targeted delivery, owing to their autonomous propulsion and improved navigation capacities across biological barriers, which further facilitate the development of GBM-targeted strategies. This review presents an overview of technological progress in different drug administration methods for GBM. Additionally, the limitations in clinical translation and future research prospects in this field are also discussed. This review aims to provide a comprehensive guideline for researchers and offer perspectives on further development of new drug delivery therapies to combat GBM.

Phase 1b study of intraperitoneal ipilimumab and nivolumab in patients with recurrent gynecologic malignancies with peritoneal carcinomatosis

BACKGROUND

Intravenous immune checkpoint blockade (ICB) has shown poor response rates in recurrent gynecologic malignancies. Intraperitoneal (i.p.) ICB may result in enhanced T cell activation and anti-tumor immunity.

METHODS

In this phase 1b study, registered at Clinical.

TRIALS

gov (NCT03508570), initial cohorts received i.p. nivolumab monotherapy, and subsequent cohorts received combination i.p. nivolumab every 2 weeks and i.p. ipilimumab every 6 weeks, guided by a Bayesian design. The primary objective was determination of the recommended phase 2 dose (RP2D) of the combination. Secondary outcomes included toxicity, objective response rate (ORR), progression-free survival (PFS), and overall survival (OS).

FINDINGS

The trial enrolled 23 patients: 18 with ovarian cancer, 2 with uterine cancer, and 3 with cervical cancer. Study evaluable patients (n = 16) received a median of 2 prior lines of therapy (range: 1-8). Partial response was observed in 2 patients (12.5%; 1 ovarian, 1 uterine), and complete response was observed in 1 patient (6.3%) with cervical cancer, for an ORR of 18.8% (95% confidence interval: 4.0%-45.6%). The median duration of response was 14.8 months (range: 4.1-20.8), with one complete response ongoing. Median PFS and OS were 2.7 months and not reached, respectively. Grade 3 or higher immune-related adverse events occurred in 2 (8.7%) patients.

CONCLUSIONS

i.p. administration of dual ICB is safe and demonstrated durable responses in a subset of patients with advanced gynecologic malignancy. The RP2D is 3 mg/kg i.p. nivolumab every 2 weeks plus 1 mg/kg ipilimumab every 6 weeks.

FUNDING

This work was funded by Bristol Myers Squibb (CA209-9C7), an MD Anderson Cancer Center Support Grant (CA016672), the Ovarian Cancer Moon Shots Program, the Emerson Collective Fund, and a T32 training grant (CA101642).

Emerging therapeutic approaches for peritoneal metastases from gastrointestinal cancers

Peritoneal metastases from gastrointestinal malignancies present difficult management decisions, with options consisting primarily of systemic chemotherapy or major surgery with or without hyperthermic intraperitoneal chemotherapy. Current research is investigating expanding therapeutic modalities, and the aim of this review is to provide an overview of the existing and emerging therapies for the peritoneal metastases from gastrointestinal cancers, primarily through the recent literature (2015 and newer). These include the current data with systemic therapy and cytoreduction with hyperthermic intraperitoneal or pressurized intraperitoneal aerosol chemotherapy, as well as novel promising modalities under investigation, including dominating oncolytic viral therapy and adoptive cellular, biologic, and bacteria therapy, or nanotechnology. The novel diverse strategies, although preliminary and preclinical in murine models, individually and collectively contribute to the treatment of peritoneal metastases, offering hope for improved outcomes and quality of life. We foresee that these evolving treatment approaches will facilitate the transfer of knowledge and data among studies and advance discovery of new drugs and optimized treatments for patients with peritoneal metastases.

Adoptive T Cell Therapy in Solid Tumors: State-of-the Art, Current Challenges, and Upcoming Improvements

In solid tumors, three main complementary approaches of adoptive T-cell therapies were successively developed: tumor-infiltrating lymphocytes, chimeric antigen receptor engineered T cells, and high-affinity T-cell receptor engineered T cells. In this review, we summarized rational and main results of these three adoptive T-cell therapies in solid tumors field and gave an overview of encouraging data and their limits. Then, we listed the major remaining challenges (including tumor antigen loss, on-target/off-tumor effect, tumor access difficulties and general/local immunosubversion) and their lines of research. Finally, we gave insight into the ongoing trials in solid tumor.

Characterizing the Immune Environment in Peritoneal Carcinomatosis: Insights for Novel Immunotherapy Strategies

BACKGROUND OR PURPOSE

Carcinomatosis, a distinct pattern of metastatic cancer in the peritoneal cavity, poses challenges for treatment and has limited therapeutic options. Understanding the immune environment of peritoneal surface malignancies is crucial for developing effective immunotherapeutic approaches. This study characterizes soluble immune mediators in the peritoneal fluid of patients with and without carcinomatosis to identify targets for novel treatment strategies.

PATIENTS AND METHODS

Serum and peritoneal fluid samples were collected from surgical patients, and a multianalyte analysis was performed using the Luminex platform. Patient characteristics, tumor sites, and sample collection details were recorded. Soluble immune mediator levels were measured and compared between peritoneal fluid and serum samples and among clinical subgroups. Statistical analysis was conducted to assess differences in analyte concentrations and correlations between samples.

RESULTS

There were 39 patients included in the study, with varying surgical indications. Significant differences were observed in soluble immune mediator levels between peritoneal fluid and serum, with peritoneal fluid exhibiting lower concentrations. Carcinomatosis was associated with elevated levels of proinflammatory mediators, including IL-6 and IL-8, while adaptive immune response markers were low in peritoneal fluid.

CONCLUSIONS

The peritoneal immune microenvironment in carcinomatosis favors innate immunity, presenting a challenging environment for effective antitumor response. High levels of proinflammatory mediators suggest potential targets for intervention, such as the IL-6 axis, FGF2, IL-8, and CCL2; these could be explored as potential mitigators of malignant ascites and enhance anti-tumor immune responses. These findings provide valuable insights for developing immunotherapy strategies and improving outcomes in patients with peritoneal carcinomatosis.

Immunotherapy Innovations in the Fight against Osteosarcoma: Emerging Strategies and Promising Progress

Immunosuppressive elements within the tumor microenvironment are the primary drivers of tumorigenesis and malignant advancement. The presence, as well as the crosstalk between myeloid-derived suppressor cells (MDSCs), osteosarcoma-associated macrophages (OS-Ms), regulatory T cells (Tregs), and endothelial cells (ECs) with osteosarcoma cells cause the poor prognosis of OS. In addition, the consequent immunosuppressive factors favor the loss of treatment potential. Nanoparticles offer a means to dynamically and locally manipulate immuno-nanoparticles, which present a promising strategy for transforming OS-TME. Additionally, chimeric antigen receptor (CAR) technology is effective in combating OS. This review summarizes the essential mechanisms of immunosuppressive cells in the OS-TME and the current immune-associated strategies. The last part highlights the limitations of existing therapies and offers insights into future research directions.

Injectable Supramolecular Hydrogels for In Situ Programming of Car-T Cells toward Solid Tumor Immunotherapy

Chimeric antigen receptor (CAR)-T cell immunotherapy is approved in the treatment of hematological malignancies, but remains far from satisfactory in solid tumor treatment due to inadequate intra-tumor CAR-T cell infiltration. Herein, an injectable supramolecular hydrogel system, based on self-assembly between cationic polymer mPEG-PCL-PEI (PPP) conjugated with T cell targeting anti-CD3e f(ab')2 fragment and α-cyclodextrin (α-CD), is designed to load plasmid CAR (pCAR) with a T cell specific CD2 promoter, which successfully achieves in situ fabrication and effective accumulation of CAR-T cells at the tumor site in humanized mice models. More importantly, due to this tumor microenvironment reprogramming, secretion of cellular inflammatory cytokines (interleukin-2 (IL-2), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ)) or tumor killer protein granzyme B is significantly promoted, which reverses the immunosuppressive microenvironment and significantly enhances the intra-tumor CAR-T cells and cytotoxic T cells infiltration. To the best of the current knowledge, this is a pioneer report of using injectable supramolecular hydrogel for in situ reprogramming CAR-T cells, which might be beneficial for solid tumor CAR-T immunotherapy.

Intraperitoneal administration of carcinoembryonic antigen-directed chimeric antigen receptor T cells is a robust delivery route for effective treatment of peritoneal carcinomatosis from colorectal cancer in pre-clinical study

BACKGROUND AIMS

Peritoneal carcinomatosis (PC) from colorectal cancer (CRC) is a highly challenging disease to treat. Systemic chimeric antigen receptor (CAR) T cells have shown impressive efficacy in hematologic malignancies but have been less effective in solid tumors. We explored whether intraperitoneal (i.p.) administration of CAR T cells could provide an effective and robust route of treatment for PC from CRC.

METHODS

We generated second-generation carcinoembryonic antigen (CEA)-specific CAR T cells. Various animal models of PC with i.p. and extraperitoneal metastasis were treated by i.p. or intravenous (i.v.) administration of CEA CAR T cells.

RESULTS

Intraperitoneally administered CAR T cells exhibited superior anti-tumor activity compared with systemic i.v. cell infusion in an animal model of PC. In addition, i.p. administration conferred a durable effect and protection against tumor recurrence and exerted strong anti-tumor activity in an animal model of PC with metastasis in i.p. or extraperitoneal organs. Moreover, compared with systemic delivery, i.p. transfer of CAR T cells provided increased anti-tumor activity in extraperitoneal tumors without PC. This phenomenon was further confirmed in an animal model of pancreatic carcinoma after i.p. administration of our newly constructed prostate stem cell antigen-directed CAR T cells.

CONCLUSIONS

Taken together, our data suggest that i.p. administration of CAR T cells may be a robust delivery route for effective treatment of cancer.

The significance of the omentum in locoregional immunotherapy for peritoneal carcinomatosis

Our recent research has unveiled the potential of locoregional immunotherapy. Cytokine-armored viral vectors, such as modified vaccinia virus Ankara vector encoding single-chain interleukin-12 (MVA.scIL-12), can target the omentum and elicit a robust tumor-specific immune response, all the while minimizing toxicity.

"Hurdles race for CAR T-cell therapy in digestive tract cancer"

Digestive tract cancers (DTC) belong to the most investigated family of tumors. The incidence, prevalence, and mortality rate of DTC remain high, especially for patients with pancreatic cancer. Even though immunotherapy such as immune checkpoint inhibitors (ICI) have revolutionized the treatment of solid cancer types, ICI are still restricted to a very small group of patients and seem to be more efficacious in combination with chemotherapy. Cellular immunotherapy such as CAR T-cell therapy has entered clinical routine in hematological malignancies with outstanding results. There is growing interest on translating this kind of immunotherapy and success into patients with solid malignancies, such as DTC. This review attempts to describe the major advances in preclinical and clinical research with CAR T cells in DTC, considering the most relevant hurdles in each subtype of DTC.

Immune profile of patients with peritoneal carcinomatosis selected for CRS-HIPEC therapy

Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is a treatment option for peritoneal carcinomatosis (PC) from colorectal cancer (CRC), which is otherwise a terminal stage of disease. Nevertheless, survival outcomes are only marginally superior to other treatments. This fact highlights the need for better strategies to control intra-abdominal disease recurrence after CRS-HIPEC, including the complementary use of immunotherapies. The aim of this study was therefore to investigate the immune phenotype of T cells in patients with PC. Fifty three patients with CRC (34 patients with PC and 19 patients without PC) were enrolled in a prospective study (clinicaltrials.gov: NCT04108936). Peripheral blood and omental fat were collected to isolate peripheral blood mononuclear cells (PBMCs) and adipose tissue mononuclear cells (ATMCs). These cells were analysed by flow cytometry using a panel focused upon T cell memory differentiation and exhaustion markers. We found a more naïve profile for CD8+ T cells in peripheral blood and intra-abdominal fat of PC patients compared to comparator group (CG) patients. Furthermore, there was an over-representation of CD4+ T cells expressing inhibitory receptors in adipose tissue of PC patients, but not in blood. Our description of intraperitoneal T cell subsets gives us a better understanding of how peritoneal carcinomatosis shapes local immune responses.

Regional Immunotherapy for Peritoneal Carcinomatosis in Gastroesophageal Cancer: Emerging Strategies to Re-Condition a Maladaptive Tumor Environment

Peritoneal carcinomatosis originating from gastric/gastroesophageal junction cancer (GC-PC) occurs in a defined subset of gastric cancer patients with unique clinical, pathologic, molecular and immunologic characteristics that create significant obstacles to effective treatment with modern therapy. Although systemic chemo- and immuno- therapy have yielded disappointing results in GC-PC, recent advances in the characterization of GC-PC and peritoneal immune biology present new opportunities for targeted therapeutics. In this review article, we discuss the distinct properties of GC-PC and the peritoneal immune environment as they pertain to current and investigative treatment strategies. We discuss pre-clinical studies and clinical trials relevant to the modulation of the peritoneal environment as a therapeutic intervention in GC-PC. Finally, we present a road map for future combinatorial strategies based on the conception of the peritoneal cavity as a bioreactor. Within this isolated compartment, prevailing immunosuppressive conditions can be altered through regional interventions toward an adaptive phenotype that would support the effectiveness of regionally delivered cellular therapy products. It is hoped that novel combination strategies would promote efficacy not only in the sequestered peritoneal environment, but also via migration into the circulation of tumor-reactive lymphocytes to produce durable systemic disease control, thereby improving oncologic outcome and quality of life in patients with GC-PC.

Harnessing the potential of CAR-T cell therapy: progress, challenges, and future directions in hematological and solid tumor treatments

Traditional cancer treatments use nonspecific drugs and monoclonal antibodies to target tumor cells. Chimeric antigen receptor (CAR)-T cell therapy, however, leverages the immune system's T-cells to recognize and attack tumor cells. T-cells are isolated from patients and modified to target tumor-associated antigens. CAR-T therapy has achieved FDA approval for treating blood cancers like B-cell acute lymphoblastic leukemia, large B-cell lymphoma, and multiple myeloma by targeting CD-19 and B-cell maturation antigens. Bi-specific chimeric antigen receptors may contribute to mitigating tumor antigen escape, but their efficacy could be limited in cases where certain tumor cells do not express the targeted antigens. Despite success in blood cancers, CAR-T technology faces challenges in solid tumors, including lack of reliable tumor-associated antigens, hypoxic cores, immunosuppressive tumor environments, enhanced reactive oxygen species, and decreased T-cell infiltration. To overcome these challenges, current research aims to identify reliable tumor-associated antigens and develop cost-effective, tumor microenvironment-specific CAR-T cells. This review covers the evolution of CAR-T therapy against various tumors, including hematological and solid tumors, highlights challenges faced by CAR-T cell therapy, and suggests strategies to overcome these obstacles, such as utilizing single-cell RNA sequencing and artificial intelligence to optimize clinical-grade CAR-T cells.

Adjuvant Therapy with Oncolytic Adenovirus Delta-24-RGDOX After Intratumoral Adoptive T-cell Therapy Promotes Antigen Spread to Sustain Systemic Antitumor Immunity

Cancer cell heterogeneity and immunosuppressive tumor microenvironment (TME) pose a challenge in treating solid tumors with adoptive cell therapies targeting limited tumor-associated antigens (TAA), such as chimeric antigen receptor T-cell therapy. We hypothesize that oncolytic adenovirus Delta-24-RGDOX activates the TME and promote antigen spread to potentiate the abscopal effect of adoptive TAA-targeting T cells in localized intratumoral treatment. Herein, we used C57BL/6 mouse models with disseminated tumors derived from B16 melanoma cell lines to assess therapeutic effects and antitumor immunity. gp100-specific pmel-1 or ovalbumin (OVA)-specific OT-I T cells were injected into the first subcutaneous tumor, followed by three injections of Delta-24-RGDOX. We found TAA-targeting T cells injected into one subcutaneous tumor showed tumor tropism. Delta-24-RGDOX sustained the systemic tumor regression mediated by the T cells, leading to improved survival rate. Further analysis revealed that, in mice with disseminated B16-OVA tumors, Delta-24-RGDOX increased CD8⁺ leukocyte density within treated and untreated tumors. Importantly, Delta-24-RGDOX significantly reduced the immunosuppression of endogenous OVA-specific CTLs while increasing that of CD8⁺ leukocytes and, to a lesser extent, adoptive pmel-1 T cells. Consequently, Delta-24-RGDOX drastically increased the density of the OVA-specific CTLs in both tumors, and the combination synergistically enhanced the effect. Consistently, the splenocytes from the combination group showed a significantly stronger response against other TAAs (OVA and TRP2) than gp100, resulted in higher activity against tumor cells. Therefore, our data demonstrate that, as an adjuvant therapy followed TAA-targeting T cells in localized treatment, Delta-24-RGDOX activates TME and promotes antigen spread, leading to efficacious systemic antitumor immunity to overcome tumor relapse.

Significance

Adjuvant therapy with oncolytic viruses promotes antigen spread to potentiate localized intratumoral adoptive T-cell therapy with limited TAA targets, leading to sustainable systemic antitumor immunity to overcome tumor relapse.

Understanding CAR T cell therapy and its role in ovarian cancer and peritoneal carcinomatosis from ovarian cancer

Ovarian cancer is the seventh most common cancer worldwide in women and the most lethal gynecologic malignancy due to the lack of accurate screening tools for early detection and late symptom onset. The absence of early-onset symptoms often delays diagnosis until the disease has progressed to advanced stages, frequently when there is peritoneal involvement. Although ovarian cancer is a heterogeneous malignancy with different histopathologic types, treatment for advanced tumors is usually based on chemotherapy and cytoreduction surgery. CAR T cells have shown promise for the treatment of hematological malignancies, though their role in treating solid tumors remains unclear. Outcomes are less favorable owing to the low capacity of CAR T cells to migrate to the tumor site, the influence of the protective tumor microenvironment, and the heterogeneity of surface antigens on tumor cells. Despite these results, CAR T cells have been proposed as a treatment approach for peritoneal carcinomatosis from colorectal and gastric origin. Local intraperitoneal administration of CAR T cells has been found to be superior to systemic administration, as this route is associated with increased tumor reduction, a more durable effect, protection against local relapse and distant metastases, and fewer systemic adverse effects. In this article we review the application of CAR T cells for the treatment of ovarian cancer and peritoneal carcinomatosis from ovarian cancer.

Immunotherapy for Peritoneal Carcinomatosis: Challenges and Prospective Outcomes

Peritoneal metastasis, also known as peritoneal carcinomatosis (PC), is a refractory cancer that is typically resistant to conventional therapies. The typical treatment for PC is a combination of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Recently, research in this area has seen significant advances, particularly in immunotherapy as an alternative therapy for PC, which is very encouraging. Catumaxomab is a trifunctional antibody intraperitoneal (IP) immunotherapy authorized in Europe that can be used to diminish malignant ascites by targeting EpCAM. Intraperitoneal (IP) immunotherapy breaks immunological tolerance to treat peritoneal illness. Increasing T-cell responses and vaccination against tumor-associated antigens are two methods of treatment. CAR-T cells, vaccine-based therapeutics, dendritic cells (DCs) in combination with pro-inflammatory cytokines and NKs, adoptive cell transfer, and immune checkpoint inhibitors are promising treatments for PC. Carcinoembryonic antigen-expressing tumors are suppressed by IP administration of CAR-T cells. This reaction was strengthened by anti-PD-L1 or anti-Gr1. When paired with CD137 co-stimulatory signaling, CAR-T cells for folate receptor cancers made it easier for T-cell tumors to find their way to and stay alive in the body.

[CAR-T cells development in solid tumors]

CAR-T cells have produced very promising results in the field of onco-hematology and have been rapidly approved for marketing in France for several years now. In solid tumors, current results are more disappointing. Indeed, many hurdles come in the way. Tumor vascularization, the strongly immunosuppressive microenvironment, the loss of the target antigen as well as T cell exhaustion are part of the explanation of those results. Hence many researchers are working to develop strategies to counteract these resistance mechanisms. Arming CAR-T cells with BiTEs, with immune checkpoint inhibitors or with interleukins seem to be effective ways to improve antitumor efficacy. Other strategies including vaccines association or local delivery of the CAR-T cells look very promising. Many Phase I studies are investigating these new strategies and are expected to improve the previous results obtained to date in this area.

Systemic enhancement of antitumour immunity by peritumourally implanted immunomodulatory macroporous scaffolds

A tumour microenvironment abundant in regulatory T (Treg) cells aids solid tumours to evade clearance by effector T cells. Systemic strategies to suppress Treg cells or to augment immunity can elicit autoimmune side effects, cytokine storms and other toxicities. Here we report the design, fabrication and therapeutic performance of a biodegradable macroporous scaffold, implanted peritumourally, that releases a small-molecule inhibitor of transforming growth factor β to suppress Treg cells, chemokines to attract effector T cells and antibodies to stimulate them. In two mouse models of aggressive tumours, the implant boosted the recruitment and activation of effector T cells into the tumour and depleted it of Treg cells, which resulted in an 'immunological abscopal effect' on distant metastases and in the establishment of long-term memory that impeded tumour recurrence. We also show that the scaffold can be used to deliver tumour-antigen-specific T cells into the tumour. Peritumourally implanted immunomodulatory scaffolds may represent a general strategy to enhance T-cell immunity and avoid the toxicities of systemic therapies.

Intracavitary adoptive transfer of IL-12 mRNA-engineered tumor-specific CD8+ T cells eradicates peritoneal metastases in mouse models

Previous studies have shown that local delivery of tumor antigen-specific CD8⁺ T lymphocytes engineered to transiently express single-chain IL-12 mRNA is highly efficacious. Peritoneal dissemination of cancer is a frequent and often fatal patient condition usually diagnosed when the tumor burden is too large and hence uncontrollable with current treatment options. In this study, we have modeled intracavitary adoptive T cell therapy with OVA-specific OT-I T cells electroporated with IL-12 mRNA to treat B16-OVA and PANC02-OVA tumor spread in the peritoneal cavity. Tumor localization in the omentum and the effects of local T-cell encounter with the tumor antigens were monitored, the gene expression profile evaluated, and the phenotypic reprogramming of several immune subsets was characterized. Intraperitoneal administration of T cells promoted homing to the omentum more effectively than intravenous administration. Transient IL-12 expression was responsible for a favorable reprogramming of the tumor immune microenvironment, longer persistence of transferred T lymphocytes in vivo, and the development of immunity to endogenous antigens following primary tumor eradication. The efficacy of the strategy was at least in part recapitulated with the adoptive transfer of lower affinity transgenic TCR-bearing PMEL-1 T lymphocytes to treat the aggressive intraperitoneally disseminated B16-F10 tumor. Locoregional adoptive transfer of transiently IL-12-armored T cells appears to offer promising therapeutic advantages in terms of anti-tumor efficacy to treat peritoneal carcinomatosis.

Combining locoregional CAR-T cells, autologous + allogeneic tumor lysate vaccination and levamisole in treatment of glioblastoma

Glioblastoma multiforme (GBM) is an aggressive brain malignancy and harbors a microenvironment limiting immune cells activity. CAR-T cells are being tested in the treatment of cancers and there exist reports which demonstrate dramatic regression of multicentric GBMs following intrathecal treatment with CAR-T cells. In this article, a triple approach for immune treatment of GBM is proposed. First, GBM tumor specimens for each patient will be saved and cultured to obtain tumor lysates. Then, levamisole will be applied, which possesses immunostimulating, anti-glycolytic, and anti-angiogenic features. Following priming the immune system, GBM patients will be injected with lysates of their own tumor cells plus lysates from a GBM cell line, U251. After 3 months of this treatment, CAR-T cells (transduced with IL13Rα2-CAR) will be applied via intratumoral approach. As such, genetically-modified and native immunocytes may 'meet' in the vicinity of deeply-invading tumor cells and demonstrate greater efficacy via cell-cell interactions. By this, a self-propagating cyclic process - a cancer-immunity cycle - may be initiated to eradicate cancer cells.

CAR-T cell therapy in triple-negative breast cancer: Hunting the invisible devil

Triple-negative breast cancer (TNBC) is known as the most intricate and hard-to-treat subtype of breast cancer. TNBC cells do not express the well-known estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2) expressed by other breast cancer subtypes. This phenomenon leaves no room for novel treatment approaches including endocrine and HER2-specific antibody therapies. To date, surgery, radiotherapy, and systemic chemotherapy remain the principal therapy options for TNBC treatment. However, in numerous cases, these approaches either result in minimal clinical benefit or are nonfunctional, resulting in disease recurrence and poor prognosis. Nowadays, chimeric antigen receptor T cell (CAR-T) therapy is becoming more established as an option for the treatment of various types of hematologic malignancies. CAR-Ts are genetically engineered T lymphocytes that employ the body’s immune system mechanisms to selectively recognize cancer cells expressing tumor-associated antigens (TAAs) of interest and efficiently eliminate them. However, despite the clinical triumph of CAR-T therapy in hematologic neoplasms, CAR-T therapy of solid tumors, including TNBC, has been much more challenging. In this review, we will discuss the success of CAR-T therapy in hematological neoplasms and its caveats in solid tumors, and then we summarize the potential CAR-T targetable TAAs in TNBC studied in different investigational stages.

CAR-T cell therapy in triple-negative breast cancer: Hunting the invisible devil

Triple-negative breast cancer (TNBC) is known as the most intricate and hard-to-treat subtype of breast cancer. TNBC cells do not express the well-known estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2) expressed by other breast cancer subtypes. This phenomenon leaves no room for novel treatment approaches including endocrine and HER2-specific antibody therapies. To date, surgery, radiotherapy, and systemic chemotherapy remain the principal therapy options for TNBC treatment. However, in numerous cases, these approaches either result in minimal clinical benefit or are nonfunctional, resulting in disease recurrence and poor prognosis. Nowadays, chimeric antigen receptor T cell (CAR-T) therapy is becoming more established as an option for the treatment of various types of hematologic malignancies. CAR-Ts are genetically engineered T lymphocytes that employ the body's immune system mechanisms to selectively recognize cancer cells expressing tumor-associated antigens (TAAs) of interest and efficiently eliminate them. However, despite the clinical triumph of CAR-T therapy in hematologic neoplasms, CAR-T therapy of solid tumors, including TNBC, has been much more challenging. In this review, we will discuss the success of CAR-T therapy in hematological neoplasms and its caveats in solid tumors, and then we summarize the potential CAR-T targetable TAAs in TNBC studied in different investigational stages.

Recruiting Immunity for the Fight against Colorectal Cancer: Current Status and Challenges

Cancer immunotherapies have changed the landscape of cancer management and improved the standard treatment protocols used in multiple tumors. This has led to significant improvements in progression-free survival and overall survival rates. In this review article, we provide an insight into the major immunotherapeutic methods that are currently under investigation for colorectal cancer (CRC) and their clinical implementations. We emphasize therapies that are based on monoclonal antibodies (mAbs) and adoptive cell therapy, their mechanisms of action, their advantages, and their potential in combination therapy. We also highlight the clinical trials that have demonstrated both the therapeutic efficacy and the toxicities associated with each method. In addition, we summarize emerging targets that are now being evaluated as potential interventions for CRC. Finally, we discuss current challenges and future direction for the cancer immunotherapy field.

Recent findings on chimeric antigen receptor (CAR)-engineered immune cell therapy in solid tumors and hematological malignancies

Advancements in adoptive cell therapy over the last four decades have revealed various new therapeutic strategies, such as chimeric antigen receptors (CARs), which are dedicated immune cells that are engineered and administered to eliminate cancer cells. In this context, CAR T-cells have shown significant promise in the treatment of hematological malignancies. However, many obstacles limit the efficacy of CAR T-cell therapy in both solid tumors and hematological malignancies. Consequently, CAR-NK and CAR-M cell therapies have recently emerged as novel therapeutic options for addressing the challenges associated with CAR T-cell therapies. Currently, many CAR immune cell trials are underway in various human malignancies around the world to improve antitumor activity and reduce the toxicity of CAR immune cell therapy. This review will describe the comprehensive literature of recent findings on CAR immune cell therapy in a wide range of human malignancies, as well as the challenges that have emerged in recent years.

Targeting glycans for CAR therapy: The advent of sweet CARs

Chimeric antigen receptor (CAR) T cell therapy has created a paradigm shift in the treatment of hematologic malignancies but has not been as effective toward solid tumors. For such tumors, the primary obstacles facing CAR T cells are scarcity of tumor-specific antigens and the hostile and complex tumor microenvironment. Glycosylation, the process by which sugars are post-translationally added to proteins or lipids, is profoundly dysregulated in cancer. Abnormally glycosylated glycoproteins expressed on cancer cells offer unique targets for CAR T therapy as they are specific to tumor cells. Tumor stromal cells also express abnormal glycoproteins and thus also have the potential to be targeted by glycan-binding CAR T cells. This review will discuss the state of CAR T cells in the therapy of solid tumors, the cancer glycoproteome and its potential for use as a therapeutic target, and the landscape and future of glycan-binding CAR T cell therapy.

Peritoneal carcinomatosis with intraperitoneal immunotherapy: current treatment options and perspectives

INTRODUCTION

Peritoneal carcinomatosis (PC) is an advanced malignancy that is not sensitive to systemic conventional chemotherapy. Treatment options for PC are usually palliative rather than curative. Cytoreductive surgery and hyperthermic intraperitoneal (IP) chemotherapy are associated with limited efficacy in patients with PC. However, the peritoneum can produce effective immunity by inducing T-lymphocyte recruitment and proliferation, and the unique immune environment of the peritoneum provides the rationale for IP immunotherapy in PC.

AREAS COVERED

The authors retrieved relevant documents of IP immunotherapy for PC from PubMed and Medline. This review elaborates on the knowledge of the peritoneal immune microenvironment and IP immunotherapy for PC covering immune stimulators, radioimmunotherapy, catumaxomab, cancer vaccines, chimeric antigen receptor (CAR)-T cells, and immune checkpoint inhibitors.

EXPERT OPINION

The prognosis of PC is poor. However, the peritoneal cavity is a unique immune compartment with abundant immune cells which can produce effective immunity. IP immunotherapy may be a promising strategy in patients with PC.

Customized Multifunctional Peptide Hydrogel Scaffolds for CAR-T-Cell Rapid Proliferation and Solid Tumor Immunotherapy

CAR-T-cell therapies must be expanded to obtain a large number of effector cells quickly, and the current technology cannot address this challenge. A longer operational time would lose or alter the function and phenotype of CAR-T cells in response to therapy, and it also causes a loss in the optimal treatment time for patients. At present, lower survival time and homing efficiency reduce the antitumor effect of CAR-T in vivo. But nobody has solved these two issues in one system, which has a similar microenvironment of lymphoid organs to activate/expand cell delivery for immunotherapy. Here, we generated artificial, customized immune cell matrix scaffolds based on a self-assembling peptide to preserve and augment the cell phenotype in light of the characteristics of CAR-T. The all-in-one nanoscale matrix scaffolds reduced the processing time of CAR-T to 3 days and resulted in over a 10-fold increase compared with the traditional protocol. The cells were combined to modulate mechanotransduction and chemical signals, and the mimic matrix scaffolds showed optimal stiffness and adhesive ligand density, thereby accelerating CAR-T-cell proliferation. Meanwhile, engineering CAR-T-secreted intrinsic PD-1 blocking single-chain variable fragments (scFv) further increased cell proliferation and cytotoxicity by resisting the self and tumor microenvironment in a paracrine and autocrine manner. Local delivery of CAR-T cells from the scaffolds significantly enabled long-term retention, suppressed tumor growth, and increased infiltration of effector T cells compared with traditional CAR-T treatment. The application of bioengineering and genetic engineering approaches has led to the development of rapid culture environments that can control matrix scaffold properties for CAR-T-cell and cancer immunotherapies.

From Anti-HER-2 to Anti-HER-2-CAR-T Cells: An Evolutionary Immunotherapy Approach for Gastric Cancer

Current Therapeutic modalities provide no survival advantage to gastric cancer (GC) patients. Targeting the human epidermal growth factor receptor-2 (HER-2) is a viable therapeutic strategy against advanced HER-2 positive GC. Antibody-drug conjugates, small-molecule tyrosine kinase inhibitors (TKIs), and bispecific antibodies are emerging as novel drug forms that may abrogate the resistance to HER-2-specific drugs and monoclonal antibodies. Chimeric antigen receptor-modified T cells (CAR-T) targeting HER-2 have shown considerable therapeutic potential in GC and other solid tumors. However, due to the high heterogeneity along with the complex tumor microenvironment (TME) of GC that often leads to immune escape, the immunological treatment of GC still faces many challenges. Here, we reviewed and discussed the current progress in the research of anti-HER-2-CAR-T cell immunotherapy against GC.

Molecular Mechanisms and Potential Rationale of Immunotherapy in Peritoneal Metastasis of Advanced Gastric Cancer

Peritoneal metastasis (PM) is one of the most frequent metastasis patterns of gastric cancer (GC), and the prognosis of patients with PM is very dismal. According to Paget’s theory, disseminated free cancer cells are seeded and survive in the abdominal cavity, adhere to the peritoneum, invade the subperitoneal tissue, and proliferate through angiogenesis. In these sequential processes, several key molecules are involved. From a therapeutic point of view, immunotherapy with chemotherapy combination has become the standard of care for advanced GC. Several clinical trials of newer immunotherapy agents are ongoing. Understanding of the molecular process of PM and the potential rationale of immunotherapy for PM treatment is necessary. Beyond understanding of the molecular aspect of PM, many studies have been conducted on the modality of treatment of PM. Notably, intraperitoneal approaches, including chemotherapy or immunotherapy, have been conducted, because systemic treatment of PM has limitations. In this study, we reviewed the molecular mechanisms and immunologic aspects of PM, and intraperitoneal approaches under investigation for treating PM.

Recent Advances in Solid Tumor CAR-T Cell Therapy: Driving Tumor Cells From Hero to Zero?

Chimeric antigen receptor T-cells (CAR-Ts) are known as revolutionary living drugs that have turned the tables of conventional cancer treatments in certain hematologic malignancies such as B-cell acute lymphoblastic leukemia (B-ALL) and diffuse large B-cell lymphoma (DLBCL) by achieving US Food and Drug Administration (FDA) approval based on their successful clinical outcomes. However, this type of therapy has not seen the light of victory in the fight against solid tumors because of various restricting caveats including heterogeneous tumor antigen expression and the immunosuppressive tumor microenvironments (TME) that negatively affect the tumor-site accessibility, infiltration, stimulation, activation, and persistence of CAR-Ts. In this review, we explore strategic twists including boosting vaccines and designing implementations that can support CAR-T expansion, proliferation, and tumoricidal capacity. We also step further by underscoring novel strategies for triggering endogenous antitumor responses and overcoming the limitation of poor CAR-T tumor-tissue infiltration and the lack of definitive tumor-specific antigens. Ultimately, we highlight how these approaches can address the mentioned arduous hurdles.

Update for Advance CAR-T Therapy in Solid Tumors, Clinical Application in Peritoneal Carcinomatosis From Colorectal Cancer and Future Prospects

Latest advances in the field of cancer immunotherapy have developed the (Chimeric Antigen Receptor) CAR-T cell therapy. This therapy was first used in hematological malignancies which obtained promising results; therefore, the use of CAR-T cells has become a popular approach for treating non-solid tumors. CAR-T cells consist of T-lymphocytes that are engineered to express an artificial receptor against any surface antigen of our choice giving us the capacity of offering precise and personalized treatment. This leaded to the development of CAR-T cells for treating solid tumors with the hope of obtaining the same result; however, their use in solid tumor and their efficacy have not achieved the expected results. The reason of these results is because solid tumors have some peculiarities that are not present in hematological malignancies. In this review we explain how CAR-T cells are made, their mechanism of action, adverse effect and how solid tumors can evade their action, and also we summarize their use in colorectal cancer and peritoneal carcinomatosis.

The next wave of cellular immunotherapies in pancreatic cancer

Pancreatic cancer is an aggressive disease that is predicted to become the second leading cause of cancer-related death worldwide by 2030. The overall 5-year survival rate is around 10%. Pancreatic cancer typically presents late with locally advanced or metastatic disease, and there are limited effective treatments available. Cellular immunotherapy, such as chimeric antigen receptor (CAR) T cell therapy, has had significant success in treating hematological malignancies. However, CAR T cell therapy efficacy in pancreatic cancer has been limited. This review provides an overview of current and ongoing CAR T cell clinical studies of pancreatic cancer and the major challenges and strategies to improve CAR T cell efficacy. These strategies include arming CAR T cells; developing off-the-shelf allogeneic CAR T cells; using other immune CAR cells, like natural killer cells and tumor-infiltrating lymphocytes; and combination therapy. Careful incorporation of preclinical models will enhance management of affected individuals, assisting incorporation of cellular immunotherapies. A multifaceted, personalized approach involving cellular immunotherapy treatment is required to improve pancreatic cancer outcomes.

Emerging Novel Combined CAR-T Cell Therapies

Simple Summary

As a result of FDA approval of CAR-T cell treatments in the last few years, this immunotherapy has provided further direction to precision medicine through its combination with other therapeutic approaches. In the past year, several review articles have been published focusing on advances in this fast-developing field, especially with respect to efforts to overcome hurdles associated with applying CAR-T cells in solid tumors. This review paper focuses on combining CAR-T cell therapy with small molecule drugs, up-to-date progress in CAR-T cell therapy research, and advances in combined CAR-T immunotherapy with other treatments targeting solid tumors.

Abstract

Chimeric antigen receptors (CAR) T cells are T cells engineered to express membrane receptors with high specificity to recognize specific target antigens presented by cancer cells and are co-stimulated with intracellular signals to increase the T cell response. CAR-T cell therapy is emerging as a novel therapeutic approach to improve T cell specificity that will lead to advances in precision medicine. CAR-T cells have had impressive outcomes in hematological malignancies. However, there continue to be significant limitations of these therapeutic responses in targeting solid malignancies such as heterogeneous antigens in solid tumors, tumor immunosuppressive microenvironment, risk of on-target/off-tumor, infiltrating CAR-T cells, immunosuppressive checkpoint molecules, and cytokines. This review paper summarizes recent approaches and innovations through combination therapies of CAR-T cells and other immunotherapy or small molecule drugs to counter the above disadvantages to potentiate the activity of CAR-T cells.

Landscape of Immunotherapy Options for Colorectal Cancer: Current Knowledge and Future Perspectives beyond Immune Checkpoint Blockade

Colorectal cancer is the third most prevalent malignancy in Western countries and a major cause of death despite recent improvements in screening programs and early detection methods. In the last decade, a growing effort has been put into better understanding how the immune system interacts with cancer cells. Even if treatments with immune checkpoint inhibitors (anti-PD1, anti-PD-L1, anti-CTLA4) were proven effective for several cancer types, the benefit for colorectal cancer patients is still limited. However, a subset of patients with deficient mismatch repair (dMMR)/microsatellite-instability-high (MSI-H) metastatic colorectal cancer has been observed to have a prolonged benefit to immune checkpoint inhibitors. As a result, pembrolizumab and nivolumab +/− ipilimumab recently obtained the Food and Drug Administration approval. This review aims to highlight the body of knowledge on immunotherapy in the colorectal cancer setting, discussing the potential mechanisms of resistance and future strategies to extend its use.

Addressing the obstacles of CAR T cell migration in solid tumors: wishing a heavy traffic

Chimeric antigen receptor T cell (CAR-T) therapy has been recognized as one of the most prosperous treatment options against certain blood-based malignancies. However, the same clinical and commercial success have been out of range in the case of solid tumors. The main contributing factor in this regard is the hostile environment the tumor cells impose that results in the exhaustion of immune effector cells alongside the abrogation of their infiltration capacity. The discovery of the underlying mechanisms and the development of reliable counterstrategies to overcome the inaccessibility of CAR-Ts to their target cells might correlate with encouraging clinical outcomes in advanced solid tumors. Here, we highlight the successive physical and metabolic barriers that systemically administered CAR-Ts face on their journey toward their target cells. Moreover, we propose meticulously-devised countertactics and combination therapies that can be applied to maximize the therapeutic benefits of CAR-T therapies against solid tumors.

Immunotherapy and Radioimmunotherapy for Desmoplastic Small Round Cell Tumor

Desmoplastic small round cell tumor (DRSCT) is a highly aggressive primitive sarcoma that primarily affects adolescent and young adult males. The 5-year survival rate is 15-30% and few curative treatment options exist. Although there is no standard treatment for DSRCT, patients are most often treated with a combination of aggressive chemotherapy, radiation, and surgery. Targeted therapy inhibitors of PDGFA and IGF-1R, which are almost uniformly overexpressed in DSRCT, have largely failed in clinical trials. As in cancer in general, interest in immunotherapy to treat DSRCT has increased in recent years. To that end, several types of immunotherapy are now being tested clinically, including monoclonal antibodies, radionuclide-conjugated antibodies, chimeric antigen receptor T cells, checkpoint inhibitors, and bispecific antibodies (BsAbs). These types of therapies may be particularly useful in DSRCT, which is frequently characterized by widespread intraperitoneal implants, which are difficult to completely remove surgically and are the frequent cause of relapse. Successful treatment with immunotherapy or radioimmunotherapy following debulking surgery could eradiate these micrometasteses and prevent relapse. Although there has been limited success to date for immunotherapy in pediatric solid tumors, the significant improvements in survival seen in the treatment of other pediatric solid tumors, such as metastatic neuroblastoma and its CNS spread, suggest a potential of immunotherapy and specifically compartmental immunotherapy in DSRCT.

Cell Therapy for Colorectal Cancer: The Promise of Chimeric Antigen Receptor (CAR)-T Cells

Colorectal cancer (CRC) is a global public health problem as it is the third most prevalent and the second most lethal cancer worldwide. Major efforts are underway to understand its molecular pathways as well as to define the tumour-associated antigens (TAAs) and tumour-specific antigens (TSAs) or neoantigens, in order to develop an effective treatment. Cell therapies are currently gaining importance, and more specifically chimeric antigen receptor (CAR)-T cell therapy, in which genetically modified T cells are redirected against the tumour antigen of interest. This immunotherapy has emerged as one of the most promising advances in cancer treatment, having successfully demonstrated its efficacy in haematological malignancies. However, in solid tumours, such as colon cancer, it is proving difficult to achieve the same results due to the shortage of TSAs, on-target off-tumour effects, low CAR-T cell infiltration and the immunosuppressive microenvironment. To address these challenges in CRC, new approaches are proposed, including combined therapies, the regional administration of CAR-T cells and more complex CAR structures, among others. This review comprehensively summarises the current landscape of CAR-T cell therapy in CRC from the potential tumour targets to the preclinical studies and clinical trials, as well as the limitations and future perspectives of this novel antitumour strategy.

The Role of CAR-T Cells in Peritoneal Carcinomatosis from Gastric Cancer: Rationale, Experimental Work, and Clinical Applications

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) have shown poor effectiveness in treating peritoneal carcinomatosis (PC) of gastric origin with a high tumor burden (high peritoneal cancer index), though there are scarce therapy alternatives that are able to improve survival. In experimental studies, chimeric antigen receptor-T (CAR-T) cell therapy has shown encouraging results in gastric cancer and is currently being evaluated in several clinical trials. Regarding PC, CAR-T cell therapy has also proven useful in experimental studies, especially when administered intraperitoneally, as this route improves cell distribution and lifespan. Although these results need to be supported by ongoing clinical trials, CAR-T cells are a promising new therapeutic approach to peritoneal metastases from gastric cancer. In this review, we summarize the current evidence of the use of CAR-T cells in gastric cancer and PC of gastric origin.

CAR T cell therapy in solid tumors; with an extensive focus on obstacles and strategies to overcome the challenges

The application of the CAR T cell therapy in hematologic malignancies holds prosperous results that intensified the unprecedented enthusiasm to employ this fascinating strategy in other types of human malignancies. Although the researchers invested a great deal of effort to exploit the utmost efficacy of these cells in the context of solid tumors, few articles reviewed obstacles and opportunities. The current review aims to provide comprehensive literature of recent advances of CAR T cell therapy in a wide range of solid tumors; and also, to discuss the original data obtained from international research laboratories on this topic. Despite promising results, several radical obstacles are on the way of this approach. This review discusses the most important drawbacks and also responds to questions on how the intrinsic features of solid tumors in addition to the tumor microenvironment-related challenges and the immune-relating adverse effects can curb satisfactory outcomes of CAR T cells. The last section allocates a special focus on innovative and contemporary policies which have already been adopted to surmount these challenges. Finally, we comment on the future research aspects in which the efficacy, as well as the safety of CAR T cell therapy, might be improved.

Liposomal Resiquimod for Enhanced Immunotherapy of Peritoneal Metastases of Colorectal Cancer

Colorectal cancer with peritoneal metastases is currently treated by cytoreductive surgery and locoregional chemotherapeutics. This standard treatment is associated with high morbidity, mortality, and recurrence rate. To augment the existing therapy, we developed a liposome-based delivery system containing 1,2-stearoyl-3-trimethylammonium-propane chloride (DSTAP), a cationic lipid, to localize a toll-like receptor agonist, resiquimod (R848), in the peritoneal cavity (PerC) for enhancing the immune response against cancer that had spread to the PerC. The liposomes delivered by intraperitoneal injection increased peritoneal retention of R848 by 14-fold while retarding its systemic absorption, leading to a 5-fold decreased peak plasma concentration compared to free R848 in mice. Within the PerC, the DSTAP-liposomes were found in ~40% of the dendritic cells by flow cytometry. DSTAP-R848 significantly upregulated interferon α (IFN-α) in the peritoneal fluid by 2-fold compared to free R848, without increasing the systemic level. Combined with oxaliplatin, a cytotoxic agent inducing immunogenic cell death, DSTAP-R848 effectively inhibited the progression of CT26 murine colorectal tumor in the PerC, while the combination with free R848 only showed a mild effect. Moreover, the combination of oxaliplatin and DSTAP-R848 significantly increased infiltration of CD8+ T cells in the PerC compared to oxaliplatin combined with free R848, indicating enhanced immune response against the tumor. The results suggest that DSTAP-R848 exhibits potential in augmenting existing therapies for treating colorectal cancer with peritoneal metastases via immune activation.

NK Cell-Mediated Eradication of Ovarian Cancer Cells with a Novel Chimeric Antigen Receptor Directed against CD44

Ovarian cancer is the most common cause of gynecological cancer-related death in the developed world. Disease recurrence and chemoresistance are major causes of poor survival rates in ovarian cancer patients. Ovarian cancer stem cells (CSCs) were shown to represent a source of tumor recurrence owing to the high resistance to chemotherapy and enhanced tumorigenicity. Chimeric antigen receptor (CAR)-based adoptive immunotherapy represents a promising strategy to reduce the risk for recurrent disease. In this study, we developed a codon-optimized third-generation CAR to specifically target CD44, a marker widely expressed on ovarian cancer cells and associated with CSC-like properties and intraperitoneal tumor spread. We equipped NK-92 cells with the anti-CD44 CAR (CD44NK) and an anti-CD19 control CAR (CD19NK) using lentiviral SIN vectors. Compared to CD19NK and untransduced NK-92 cells, CD44NK showed potent and specific cytotoxic activity against CD44-positive ovarian cancer cell lines (SKOV3 and OVCAR3) and primary ovarian cancer cells harvested from ascites. In contrast, CD44NK had less cytotoxic activity against CD44-negative A2780 cells. Specific activation of engineered NK cells was also demonstrated by interferon-γ (IFNγ) secretion assays. Furthermore, CD44NK cells still demonstrated cytotoxic activity under cisplatin treatment. Most importantly, the simultaneous treatment with CD44NK and cisplatin showed higher anti-tumor activity than sequential treatment.

Translational Applications of Hydrogels

Advances in hydrogel technology have unlocked unique and valuable capabilities that are being applied to a diverse set of translational applications. Hydrogels perform functions relevant to a range of biomedical purposes-they can deliver drugs or cells, regenerate hard and soft tissues, adhere to wet tissues, prevent bleeding, provide contrast during imaging, protect tissues or organs during radiotherapy, and improve the biocompatibility of medical implants. These capabilities make hydrogels useful for many distinct and pressing diseases and medical conditions and even for less conventional areas such as environmental engineering. In this review, we cover the major capabilities of hydrogels, with a focus on the novel benefits of injectable hydrogels, and how they relate to translational applications in medicine and the environment. We pay close attention to how the development of contemporary hydrogels requires extensive interdisciplinary collaboration to accomplish highly specific and complex biological tasks that range from cancer immunotherapy to tissue engineering to vaccination. We complement our discussion of preclinical and clinical development of hydrogels with mechanical design considerations needed for scaling injectable hydrogel technologies for clinical application. We anticipate that readers will gain a more complete picture of the expansive possibilities for hydrogels to make practical and impactful differences across numerous fields and biomedical applications.

Insight into next-generation CAR therapeutics: designing CAR T cells to improve clinical outcomes

Chimeric antigen receptor (CAR) T cell therapy has shown considerable promise for hematologic malignancies, leading to the US Food and Drug Administration approval of two CAR T cell-based therapies for the treatment of B cell acute lymphoblastic leukemia and large B cell lymphoma. Despite success in hematologic malignancies, the treatment landscape of CAR T cell therapy for solid tumors has been limited. There are unique challenges in the development of novel CAR T cell therapies to improve both safety and efficacy. Improved understanding of the immunosuppressive tumor microenvironment and resistance mechanisms has led to encouraging approaches to mitigating these obstacles. This Review will characterize challenges with current CAR T designs for hematologic malignancies and solid tumors and emphasize preclinical and clinical strategies to overcome them with novel CAR T cell therapies.

Regional Delivery of Anti-PD-1 Agent for Colorectal Liver Metastases Improves Therapeutic Index and Anti-Tumor Activity

Metastatic liver tumors have presented challenges with the use of checkpoint inhibitors (CPIs), with only limited success. We hypothesize that regional delivery (RD) of CPIs can improve activity in the liver and minimize systemic exposure, thereby reducing immune-related adverse events (irAE). Using a murine model of colorectal cancer liver metastases (LM), we confirmed high levels of PD-L1 expression on the tumor cells and liver myeloid-derived suppressor cells (L-MDSC). In vivo, we detected improved LM response at 3 mg/kg on PTD7 via portal vein (PV) regional delivery as compared to 3 mg/kg via tail vein (TV) systemic delivery (p = 0.04). The minimal effective dose at PTD7 was 5 mg/kg (p = 0.01) via TV and 0.3 mg/kg (p = 0.02) via PV. We detected 6.7-fold lower circulating CPI antibody levels in the serum using the 0.3 mg/kg PV treatment compared to the 5 mg/kg TV cohort (p < 0.001) without increased liver toxicity. Additionally, 3 mg/kg PV treatment resulted in increased tumor cell apoptotic signaling compared to 5 mg/kg TV (p < 0.05). Therefore, RD of an anti-PD-1 CPI therapy for CRCLM may improve the therapeutic index by reducing the total dose required and limiting the systemic exposure. These advantages could expand CPI indications for liver tumors.

Novel antigens of CAR T cell therapy: New roads; old destination

Chimeric antigen receptor T cell (CAR-T) therapy has so far proved itself as a reliable therapeutic option for the treatment of relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL), diffuse large B-cell lymphoma (DLBCL), multiple myeloma (MM), and mantle cell lymphoma (MCL). However, this picture is not as colorful when it comes to the treatment of solid tumors mainly due to the lack of definitive tumor antigens, as well as the immunosuppressive tumor microenvironments and poor CAR-T infiltration. The recent developments in bioinformatics and cell biology, such as single-cell RNA sequencing, have offered silver linings in the subject of tumor antigen discovery. In the current review, we summarize the development of some CAR-T therapies that target novel tumor antigens, rather than the traditionally CAR-T-targeted ones, and briefly discuss the clinical antitumor achievements of those evaluated in patients, so far. Furthermore, we propose some tumor antigens that might someday be therapeutically beneficial while targeted by CAR-Ts based on the experimental evaluations of their specific monoclonal antibodies.

CRISPR/Cas9 mediated deletion of the adenosine A2A receptor enhances CAR T cell efficacy

Adenosine is an immunosuppressive factor that limits anti-tumor immunity through the suppression of multiple immune subsets including T cells via activation of the adenosine A_2A receptor (A_2AR). Using both murine and human chimeric antigen receptor (CAR) T cells, here we show that targeting A_2AR with a clinically relevant CRISPR/Cas9 strategy significantly enhances their in vivo efficacy, leading to improved survival of mice. Effects evoked by CRISPR/Cas9 mediated gene deletion of A_2AR are superior to shRNA mediated knockdown or pharmacological blockade of A_2AR. Mechanistically, human A_2AR-edited CAR T cells are significantly resistant to adenosine-mediated transcriptional changes, resulting in enhanced production of cytokines including IFNγ and TNF, and increased expression of JAK-STAT signaling pathway associated genes. A_2AR deficient CAR T cells are well tolerated and do not induce overt pathologies in mice, supporting the use of CRISPR/Cas9 to target A_2AR for the improvement of CAR T cell function in the clinic.