Tumor-infiltrating lymphocytes for the treatment of metastatic cancer

Cancer therapy via neoepitope-specific monoclonal antibody cocktails

Cellular heterogeneity presents a significant challenge to cancer treatment. Antibody therapies targeting individual tumor-associated antigens can be extremely effective but are not suited for all patients and often fail against tumors with heterogeneous expression as tumor cells with low or no antigen expression escape targeting and develop resistance. Simultaneously targeting multiple tumor-specific proteins with multiple antibodies has the potential to overcome this barrier and improve efficacy, but relatively few widely expressed cancer-specific antigens are known. In contrast, neoepitopes, which arise from mutations unique to tumor cells, are considerably more abundant. However, since neoepitopes are not commonly shared between individuals, a patient-customized approach is necessary and motivates efforts to develop an efficient means to identify suitable target mutations and isolate neoepitope-specific monoclonal antibodies. Here, focusing on the latter goal, we use directed evolution in yeast and phage display systems to engineer antibodies from nonimmune, human antibody fragment libraries that are specific for neoepitopes previously reported in the B16F10 melanoma model. We demonstrate proof-of-concept for a pipeline that supports rapid isolation and functional enhancement of multiple neoepitope peptide-targeted monoclonal antibodies and demonstrate their robust binding to B16F10 cells and potent effector functions in vitro. These antibodies were combined and evaluated in vivo for anticancer activity in tumor-bearing mice, where they suppressed B16F10 tumor growth and prolonged survival. These findings emphasize the potential for clinical application of patient-customized antibody cocktails in the treatment of the many cancers poorly addressed by current therapies.

Recent advances in non-invasive in vivo tracking of cell-based cancer immunotherapies

Immunotherapy has been at the forefront of cancer treatment research in recent years due to an increased understanding of the immune system's role in cancer and the substantial benefits it has demonstrated compared to conventional treatment methods. In particular, immune cell-based approaches utilizing T cells, natural killer (NK) cells, macrophages, and more have shown great potential as cancer treatments. While these treatments hold promise, there are still numerous issues that limit their clinical translation, including a lack of understanding of their mechanisms and inconsistent responses to treatment. Traditionally, tissue or blood samples are collected as a means of monitoring treatment progression. However, these in vitro diagnostics are invasive and provide limited information about the real-time status of the treatment or its long-term effectiveness. To address these limitations, novel non-invasive imaging modalities have been developed. These include optical imaging, X-ray computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET) and single-photon emission computed tomography (SPECT), and photoacoustic (PA) imaging. This review focuses on methods for tracking cell-based cancer immunotherapies using these in vivo imaging modalities, thereby enhancing real-time monitoring of their therapeutic effect and predictions of their long-term efficacy.

Redirecting glucose flux during in vitro expansion generates epigenetically and metabolically superior T cells for cancer immunotherapy

Cellular therapies are living drugs whose efficacy depends on persistence and survival. Expansion of therapeutic T cells employs hypermetabolic culture conditions to promote T cell expansion. We show that typical in vitro expansion conditions generate metabolically and functionally impaired T cells more reliant on aerobic glycolysis than those expanding in vivo. We used dichloroacetate (DCA) to modulate glycolytic metabolism during expansion, resulting in elevated mitochondrial capacity, stemness, and improved antitumor efficacy in murine T cell receptor (TCR)-Tg and human CAR-T cells. DCA-conditioned T cells surprisingly show no elevated intratumoral effector function but rather have improved engraftment. DCA conditioning decreases reliance on glucose, promoting usage of serum-prevalent physiologic carbon sources. Further, DCA conditioning promotes metabolic flux from mitochondria to chromatin, resulting in increased histone acetylation at key longevity genes. Thus, hyperglycemic culture conditions promote expansion at the expense of metabolic flexibility and suggest pharmacologic metabolic rewiring as a beneficial strategy for improvement of cellular immunotherapies.

Advances and Challenges in Cervical Cancer: From Molecular Mechanisms and Global Epidemiology to Innovative Therapies and Prevention Strategies

BackgroundIn the global scenario of public health, cervical cancer poses a major threat with high mortality rates, especially in women. New incidence cases and prevalence vary across different regions, as recently shown by GLOBOCAN data. The development of cervical cancer is primarily due to persistent infection by high-risk genotypes of human papillomavirus (HPV), which is a multifaceted process that is influenced by genetic, environmental, and lifestyle factors.PurposeThe goal of this study is to thoroughly investigate cervical cancer, including its etiology, molecular mechanisms, progression, diagnosis strategies, and current therapies. This review further highlights the transformative power of HPV vaccination and screening programs in curbing the disease's burden and potentially promising novel approaches like immunotherapy and targeted therapy.Research DesignThis is a narrative review article that summarizes previous literatures regarding cervical cancer in terms of molecular mechanism, etiology, clinical developments, and prevention.Study SampleThe review encompassed studies from diverse sources, including experimental, observational, and clinical research published between 1992 and 2025.Data Collection and/or AnalysisData were collected through comprehensive literature searches using databases such as PubMed, Scopus, and the Cochrane Library with defined inclusion and exclusion criteria.ResultsNonetheless, there are gaps in research and controversies regarding vaccine coverage, screening practices, and treatment accessibility for poor populations. Precision medicine trends are emerging along with new biomarkers for early detection and personalized treatment, which also form part of this discussion. Key findings include the critical role of prevention measures in controlling the global impact of cervical cancer.ConclusionsThe paper synthesizes the existing knowledge and identifies gaps that require further research, which is significant in augmenting prevention, diagnosis, and treatment of cervical cancer towards addressing its public health implications worldwide.

Lymphocyte infiltration in breast cancer: A promising prognostic indicator

Breast cancer is a leading cause of cancer-related mortality among women worldwide, necessitating the identification of reliable prognostic markers to guide treatment and improve patient outcomes. Recent research has highlighted the prognostic significance of tumor-infiltrating lymphocytes (TILs) in breast cancer, with high levels of TILs being associated with improved survival rates and better responses to therapy. This review delves into the mechanisms driving lymphocyte infiltration, its clinical implications, and the potential for TILs to serve as predictive biomarkers in breast cancer management. The presence of TILs within the tumor microenvironment reflects a dynamic interplay between tumor cells and the host immune system. Chemokine signaling, antigen presentation, and immune checkpoint interactions are key mechanisms that facilitate the recruitment and activity of lymphocytes at the tumor site. Clinically, the density of TILs varies across breast cancer subtypes, with the most significant prognostic value observed in triple-negative and HER2-positive breast cancers. High TIL levels correlate with improved overall survival and disease-free survival, underscoring their potential as a valuable prognostic indicator. Therapeutically, the role of TILs has opened new avenues in breast cancer treatment, particularly in the realm of immunotherapy. Immune checkpoint inhibitors, adoptive cell therapy, and combination therapies leveraging TILs are being explored to enhance antitumor responses. As research progresses, the integration of TIL assessment into routine clinical practice could revolutionize personalized treatment strategies, ultimately improving prognostic accuracy and patient outcomes in breast cancer care.

In Situ Tumor-Infiltrating Lymphocyte Therapy by Local Delivery of an mRNA Encoding Membrane-Anchored Anti-CD3 Single-Chain Variable Fragment

Tumor-infiltrating lymphocyte (TIL) therapy has shown promising responses in clinical trials for highly aggressive cancers such as advanced melanoma and metastatic colorectal cancer. However, TIL therapy is still limited in clinical practice due to the complex ex vivo cell preparation process. Here, we report an "in situ TIL therapy" for the treatment of solid tumors. We utilized lipid nanoparticles for the delivery of an mRNA encoding membrane-anchored anti-CD3 single-chain variable fragment (scFv) (MA-aCD3), efficiently engineering both tumor-associated macrophages (TAMs) and tumor cells following intratumoral delivery. Expression of MA-aCD3 resulted in enhanced TIL activation, proliferation, and tumor cell engagement directly within the tumor microenvironment. In B16F10 and MC38 tumor models, concurrent expression of MA-aCD3 on TAMs and tumor cells mediated by mRNA delivery resulted in significant antitumor effects via in situ polyclonal CD8+ TIL expansion and directed cytotoxic effector functions. In addition, combinatorial treatment of MA-aCD3-encoding mRNA and antiprogrammed cell death 1 (anti-PD-1) antibodies exhibited synergistic antitumor effects on anti-PD-1 refractory B16F10 tumors. Together, our findings suggest that in situ TIL therapy is a practical and effective mRNA-based therapeutic modality for the treatment of solid tumors.

Advancements in tumor-infiltrating lymphocytes: Historical insights, contemporary milestones, and future directions in oncology therapy

Tumor-infiltrating lymphocytes (TILs) are a subtype of immune cells that infiltrate and accumulate within tumors. Studies proved that TILs can be used as prognostic and predictive markers for cancer patients' responses to immunotherapy. This review explores the modern knowledge of TILs, the challenges and opportunities for utilizing TILs in cancer treatment, such as the rise of therapies under TIL circumstances, the identification of biomarkers for TIL activity, and methods used to isolate and expand TILs for therapeutic use. Ongoing clinical trials and promising results in different cancer types are highlighted, including melanoma, ovarian, and colorectal cancer. This also focuses on ongoing efforts to improve TIL-based therapies by identifying the specific subsets of TILs that are most effective in treating cancer and developing methods to increase the functionality and persistence of TILs in the tumor microenvironment. The article recapitulates the present state TILs therapy, ongoing research, and improvements to its potency.

ncRNA-mediated SOX4 overexpression correlates with unfavorable outcomes and immune infiltration in hepatocellular carcinoma

BACKGROUND

The activity and number of immune cells in the tumor microenvironment are closely related to the overall survival of patients with hepatocellular carcinoma (HCC). The sex-determining region Y-box 4 (SOX4) gene is abnormally expressed in various tumor tissues and is critical for tumor development. However, the correlation between SOX4 expression in HCC and tumor immunity is unclear.

METHODS

SOX4 expression was explored using data from The Cancer Genome Atlas, and UALCAN databases. Real-time reverse transcription quantitative and western blotting were used to analyze SOX4 expression in several liver cancer cell lines. Additionally, correlations among SOX4 expression, cancer immune characteristics, and infiltrated immune cell gene marker sets in patients with HCC were analyzed using data from the Tumor Immune Estimation Resource, Gene Expression Profiling Interactive Analysis, and Tumor-Immune System Interactions databases. Moreover, we evaluated SOX4 expression in HCC tissues and the correlation of SOX4 expression with survival rate. Subsequently, noncoding RNAs (ncRNAs) responsible for SOX4 overexpression were identified using expression, correlation, and survival analyses.

RESULTS

SOX4 expression was significantly upregulated in HCC and correlated with a poor prognosis. Additionally, SOX4 upregulation in HCC positively correlated with immune cell infiltration, several biomarkers of immune cells, and immune checkpoint expression. Finally, the MCM3AP-AS1/hsa-miR-204-5p axis was identified as the most likely upstream ncRNA-related pathway for SOX4 in HCC. These results indicated that ncRNA-mediated upregulation of SOX4 correlated with the immune infiltration level and poor prognosis in HCC. Our findings provide new directions for the development of novel immunotherapeutic targets for HCC.

Tumor-Infiltrating Lymphocyte and Other Cell Therapies for Metastatic Melanoma

ABSTRACT

Major progress in prolonging survival of patients with advanced melanoma has been made in the past decade because of the development and approval of immune checkpoint inhibitor and targeted therapies. However, for nonresponding or relapsing patients, their prognosis is still dismal. Based on clinical trial data, treatment with adoptive cell therapies holds great promise. In patients with metastatic melanoma progressing on or nonresponsive to single-agent anti-programmed cell death 1, infusion of tumor-infiltrating lymphocytes can produce responses in up to half of patients, with durable complete responses in up to 20%. Genetic modification of peripheral blood T cells with T-cell receptors derived from tumor-specific T cells, or with chimeric antigen receptors, has the potential to further improve treatment outcomes in this refractory population. In this review, we will discuss the historical development, current status, and future perspectives of adoptive T-cell therapies in melanoma.

A replicating LCMV-based vaccine for the treatment of solid tumors

Harnessing the immune system to eradicate tumors requires identification and targeting of tumor antigens, including tumor-specific neoantigens and tumor-associated self-antigens. Tumor-associated antigens are subject to existing immune tolerance, which must be overcome by immunotherapies. Despite many novel immunotherapies reaching clinical trials, inducing self-antigen-specific immune responses remains challenging. Here, we systematically investigate viral-vector-based cancer vaccines encoding a tumor-associated self-antigen (TRP2) for the treatment of established melanomas in preclinical mouse models, alone or in combination with adoptive T cell therapy. We reveal that, unlike foreign antigens, tumor-associated antigens require replication of lymphocytic choriomeningitis virus (LCMV)-based vectors to break tolerance and induce effective antigen-specific CD8+ T cell responses. Immunization with a replicating LCMV vector leads to complete tumor rejection when combined with adoptive TRP2-specific T cell transfer. Importantly, immunization with replicating vectors leads to extended antigen persistence in secondary lymphoid organs, resulting in efficient T cell priming, which renders previously "cold" tumors open to immune infiltration and reprograms the tumor microenvironment to "hot." Our findings have important implications for the design of next-generation immunotherapies targeting solid cancers utilizing viral vectors and adoptive cell transfer.

Neutralizing IL-16 enhances the efficacy of targeting Aurora-A therapy in colorectal cancer with high lymphocyte infiltration through restoring anti-tumor immunity

Cancer cells can evade immune elimination by activating immunosuppressive signaling pathways in the tumor microenvironment (TME). Targeting immunosuppressive signaling pathways to promote antitumor immunity has become an attractive strategy for cancer therapy. Aurora-A is a well-known oncoprotein that plays a critical role in tumor progression, and its inhibition is considered a promising strategy for treating cancers. However, targeting Aurora-A has not yet got a breakthrough in clinical trials. Recent reports have indicated that inhibition of oncoproteins may reduce antitumor immunity, but the role of tumor-intrinsic Aurora-A in regulating antitumor immunity remains unclear. In this study, we demonstrated that in tumors with high lymphocyte infiltration (hot tumors), higher tumor-intrinsic Aurora-A expression is associated with a better prognosis in CRC patients. Mechanically, tumor-intrinsic Aurora-A promotes the cytotoxic activity of CD8+ T cells in immune hot CRC via negatively regulating interleukin-16 (IL-16), and the upregulation of IL-16 may impair the therapeutic effect of Aurora-A inhibition. Consequently, combination treatment with IL-16 neutralization improves the therapeutic response to Aurora-A inhibitors in immune hot CRC tumors. Our study provides evidence that tumor-intrinsic Aurora-A contributes to anti-tumor immunity depending on the status of lymphocyte infiltration, highlighting the importance of considering this aspect in cancer therapy targeting Aurora-A. Importantly, our results suggest that combining Aurora-A inhibitors with IL-16-neutralizing antibodies may represent a novel and effective approach for cancer therapy, particularly in tumors with high levels of lymphocyte infiltration.

Attenuated Salmonella carrying siRNA-PD-L1 and radiation combinatorial therapy induces tumor regression on HCC through T cell-mediated immuno-enhancement

Hepatocellular carcinoma (HCC), the most prevalent type of aggressive liver cancer, accounts for the majority of liver cancer diagnoses and fatalities. Despite recent advancements in HCC treatment, it remains one of the deadliest cancers. Radiation therapy (RT) is among the locoregional therapy modalities employed to treat unresectable or medically inoperable HCC. However, radioresistance poses a significant challenge. It has been demonstrated that RT induced the upregulation of programmed death ligand 1 (PD-L1) on tumor cells, which may affect response to PD-1-based immunotherapy, providing a rationale for combining PD-1/PD-L1 inhibitors with radiation. Here, we utilized attenuated Salmonella as a carrier to explore whether attenuated Salmonella carrying siRNA-PD-L1 could effectively enhance the antitumor effect of radiotherapy on HCC-bearing mice. Our results showed that a combination of siRNA-PD-L1 and radiotherapy had a synergistic antitumor effect by inhibiting the expression of PD-L1 induced by radiation therapy. Mechanistic insights indicated that the combination treatment significantly suppressed tumor cell proliferation, promoted cell apoptosis, and stimulated immune cell infiltration and activation in tumor tissues. Additionally, the combination treatment increased the ratios of CD4+ T, CD8+ T, and NK cells from the spleen in tumor-bearing mice. This study presents a novel therapeutic strategy for HCC treatment, especially for patients with RT resistance.

Targeting tumor microenvironment using tumor-infiltrating lymphocytes as therapeutics against tumorigenesis

The immune system plays a vital role in suppressing tumor cell progression. The tumor microenvironment augmented with significant levels of tumor-infiltrating lymphocytes has been widely investigated and it is suggested that tumor-infiltrating lymphocytes have shown a significant role in the prognosis of cancer patients. Compared to ordinary non-infiltrating lymphocytes, tumor-infiltrating lymphocytes (TILs) are a significant population of lymphocytes that infiltrate tumor tissue and have a higher level of specific immunological reactivity against tumor cells. They serve as an effective immunological defense against various malignancies. TILs are a diverse group of immune cells that are divided into immune subsets based on the pathological and physiological impact they have on the immune system. TILs mainly consist of B-cells, T-cells, or natural killer cells with diverse phenotypic and functional properties. TILs are known to be superior to other immune cells in that they can recognize a wide range of heterogeneous tumor antigens by producing many clones of T cell receptors (TCRs), outperforming treatments like TCR-T cell and CAR-T therapy. With the introduction of genetic engineering technologies, tumor-infiltrating lymphocytes (TILs) have become a ground-breaking therapeutic option for malignancies, but because of the hindrances opposed by the immune microenvironment and the mutation of antigens, the development of TILs as therapeutic has been hindered. By giving some insight into the many variables, such as the various barriers inhibiting its usage as a potential therapeutic agent, we have examined various aspects of TILs in this work.

Bad to the Bone: Emerging Approaches to Aggressive Bone Sarcomas

Bone sarcomas are rare heterogeneous tumors that affect patients of all ages including children, adolescent young adults, and older adults. They include many aggressive subtypes and patient groups with poor outcomes, poor access to clinical trials, and lack of defined standard therapeutic strategies. Conventional chondrosarcoma remains a surgical disease, with no defined role for cytotoxic therapy and no approved targeted systemic therapies. Here, we discuss promising novel targets and strategies undergoing evaluation in clinical trials. Multiagent chemotherapy has greatly improved outcomes for patients with Ewing sarcoma (ES) and osteosarcoma, but management of those with high-risk or recurrent disease remains challenging and controversial. We describe the impact of international collaborative trials, such as the rEECur study, that aim to define optimal treatment strategies for those with recurrent, refractory ES, and evidence for high-dose chemotherapy with stem-cell support. We also discuss current and emerging strategies for other small round cell sarcomas, such as CIC-rearranged, BCOR-rearranged tumors, and the evaluation of emerging novel therapeutics and trial designs that may offer a new paradigm to improve survival in these aggressive tumors with notoriously bad (to the bone) outcomes.

Engaging stemness improves cancer immunotherapy

Intra-tumoral immune cells promote the stemness of cancer stem cells (CSCs) in the tumor microenvironment (TME). CSCs promote tumor progression, relapse, and resistance to immunotherapy. Cancer stemness induces the expression of neoantigens and neo-properties in CSCs, creating an opportunity for targeted immunotherapies. Isolation of stem-like T cells or retaining stemness in T clonotypes strategies produces exhaustion-resistance T cells with superior re-expansion capacity and long-lasting responses after adoptive cell therapies. Stem cells-derived NK cells may be the next generation of NK cell products for immunotherapy. Here, we have reviewed mechanisms by which stemness factors modulated the immunoediting of the TME and summarized the potentials of CSCs in the development of immunotherapy regimens, including CAR-T cells, CAR-NK cells, cancer vaccines, and monoclonal antibodies. We have discussed the natural or genetically engineered stem-like T cells and stem cell-derived NK cells with increased cytotoxicity to tumor cells. Finally, we have provided a perspective on approaches that may improve the therapeutic efficacy of these novel adoptive cell-based products in targeting immunosuppressive TME.

Oncology Clinical Trials in Greece: Progress in the Past Decade

Cancer is established as a major contributor to global burden as millions of deaths are reported every year. Advances in molecular, epidemiologic and clinical research have led to significant improvements in prevention, screening and treatment of tumors. The purpose of the study is to describe the progress of oncology clinical trials performed in Greece during the past decade and the obstacles that still need to be addressed in cancer research. A search was conducted in the public database EU Clinical Trials Register using the algorithm 'cancer AND Greece'. Results included relevant trials approved between 2010 and 2020. A total of 480 trials were approved for conduct in Greece from 2010 to 2020. The majority are multinational, phase III trials, exploring the efficacy and safety of agents in the management of lung cancer and multiple myeloma. A variety of small-molecules and monoclonal antibodies has and is being tested against key binding targets. Based on their promising effects on patients' responses and outcomes, many have been marketed for the treatment of several cancer types and are considered milestones in cancer discovery. It goes without saying that oncology research has made tremendous steps towards the development of potent and tolerable anticancer agents, with Greece having an active role. Current efforts focus on the use of alternative designs and tools aiming at further improving patients' survival and quality of life, while globalization of clinical research is also a matter of high importance.

Tumor Infiltrating Lymphocyte (TIL) Therapy for Solid Tumor Treatment: Progressions and Challenges

Over the past decade, immunotherapy, especially cell-based immunotherapy, has provided new strategies for cancer therapy. Recent clinical studies demonstrated that adopting cell transfer of tumor-infiltrating lymphocytes (TILs) for advanced solid tumors showed good efficacy. TIL therapy is a type of cell-based immunotherapy using the patient’s own immune cells from the microenvironment of the solid tumor to kill tumor cells. In this review, we provide a comprehensive summary of the current strategies and challenges in TIL isolation and generation. Moreover, the current clinical experience of TIL therapy is summarized and discussed, with an emphasis on lymphodepletion regimen, the use of interleukin-2, and related toxicity. Furthermore, we highlight the clinical trials where TIL therapy is used independently and in combination with other types of therapy for solid cancers. Finally, the limitations, future potential, and directions of TIL therapy for solid tumor treatment are also discussed.

Modulation of intracellular kinase signaling to improve TIL stemness and function for adoptive cell therapy

INTRODUCTION

Adoptive cellular therapy with tumor-infiltrating lymphocytes (TIL) has demonstrated promising clinical benefits in several solid tumors, but the efficacy of this therapy might be compromised by the "prone-to-exhaustion" phenotype of TIL and poor persistence in vivo. This calls for a robust expansion process to produce a large number of cells for clinical usage while at the same time maintaining favorable anti-tumor function and memory phenotype. Previous studies showed that the PI3K-AKT signaling pathway plays a key role in the regulation of T cell activation, differentiation and memory formation.

METHOD

We modulated the PI3K-AKT pathway in TIL isolated from cervical and ovarian cancer by application of AKT or PI3K inhibitors or CRISPR knockout of AKT1 and/or AKT2, and characterized their effects on TIL phenotype and effector function. Mechanistic study was further performed with RNA-seq analysis of AKT1/2 KO TIL in comparison to control TIL.

RESULT

The inhibition of either PI3K or AKT led to an increase in the population of effector CD8⁺ T cells with upregulation of activation markers, elevated CD39^- CD69^- memory T cells, and significantly enhanced cytotoxicity when cocultured with tumor cell lines and patient-derived tumor samples. Moreover, dual knockout of AKT1 and AKT2 largely phenocopies the functional impact of AKT or PI3K inhibition on TIL. This result was further validated by RNA-seq analysis indicating that AKT1/2 ablation primarily regulates T cell differentiation and function-related programs.

CONCLUSION

Modulation of PI3K-AKT signaling represents a promising strategy to enhance TIL stemness and cytotoxicity and improve the clinical outcome of current TIL-based therapy to treat solid tumors.

Radiomic Signatures Associated with CD8+ Tumour-Infiltrating Lymphocytes: A Systematic Review and Quality Assessment Study

The tumour immune microenvironment influences the efficacy of immune checkpoint inhibitors. Within this microenvironment are CD8-expressing tumour-infiltrating lymphocytes (CD8+ TILs), which are an important mediator and marker of anti-tumour response. In practice, the assessment of CD8+ TILs via tissue sampling involves logistical challenges. Radiomics, the high-throughput extraction of features from medical images, may offer a novel and non-invasive alternative. We performed a systematic review of the available literature reporting radiomic signatures associated with CD8+ TILs. We also aimed to evaluate the methodological quality of the identified studies using the Radiomics Quality Score (RQS) tool, and the risk of bias and applicability with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Articles were searched from inception until 31 December 2021, in three electronic databases, and screened against eligibility criteria. Twenty-seven articles were included. A wide variety of cancers have been studied. The reported radiomic signatures were heterogeneous, with very limited reproducibility between studies of the same cancer group. The overall quality of studies was found to be less than desirable (mean RQS = 33.3%), indicating a need for technical maturation. Some potential avenues for further investigation are also discussed.

ETV1 Positively Correlated With Immune Infiltration and Poor Clinical Prognosis in Colorectal Cancer

Objective

Numerous studies recently suggested that the immune microenvironment could influence the development of colorectal cancer (CRC). These findings implied that the infiltration of immune cells could be a promising prognostic biomarker for CRC.

Methods

Furthermore, the Oncomine database and R2 platform analysis were applied in our research to validate CRC clinical prognosis via expression levels of polyoma enhancer activator 3 (PEA3) members. We explored the correlation of ETV1, ETV4, and ETV5 with tumor-infiltrating immune cells (TIICs) in CRC tumor microenvironments via the Tumor Immune Estimation Resource (TIMER) and Gene Expression Profiling Interactive Analysis (GEPIA). Immunohistochemistry (IHC) was used to validate our CRC clinical data.

Results

Our findings indicated that the upregulation of PEA3 members including ETV1 and ETV5 was positively associated with poor prognosis in CRC patients. Meanwhile, ETV1 and ETV5 may play significant roles in the development progress of CRC. Furthermore, ETV1 tends to be associated with immune infiltration of CRC, especially with cancer-associated fibroblasts and M2 macrophages.

Conclusion

These findings revealed that ETV1 and ETV5 played significant roles in the development of CRC. Moreover, ETV1 was significantly associated with the infiltration of cancer-associated fibroblasts and M2 macrophages in CRC. Targeting ETV1 can be a potential auspicious approach for CRC treatment.

Cervical cancer therapies: Current challenges and future perspectives

Cervical cancer is the fourth most common female cancer worldwide and results in over 300 000 deaths globally. The causative agent of cervical cancer is persistent infection with high-risk subtypes of the human papillomavirus and the E5, E6 and E7 viral oncoproteins cooperate with host factors to induce and maintain the malignant phenotype. Cervical cancer is a largely preventable disease and early-stage detection is associated with significantly improved survival rates. Indeed, in high-income countries with established vaccination and screening programs it is a rare disease. However, the disease is a killer for women in low- and middle-income countries who, due to limited resources, often present with advanced and untreatable disease. Treatment options include surgical interventions, chemotherapy and/or radiotherapy either alone or in combination. This review describes the initiation and progression of cervical cancer and discusses in depth the advantages and challenges faced by current cervical cancer therapies, followed by a discussion of promising and efficacious new therapies to treat cervical cancer including immunotherapies, targeted therapies, combination therapies, and genetic treatment approaches.

Defined tumor antigen-specific T cells potentiate personalized TCR-T cell therapy and prediction of immunotherapy response

Personalized immunotherapy targeting tumor-specific antigens (TSAs) could generate efficient and safe antitumor immune response without damaging normal tissues. Although neoantigen vaccines have shown therapeutic effect in clinic trials, precise prediction of neoantigens from tumor mutations is still challenging. The host antitumor immune response selects and activates T cells recognizing tumor antigens. Hence, T cells engineered with T-cell receptors (TCRs) from these naturally occurring tumor antigen-specific T (Tas) cells in a patient will target personal TSAs in his/her tumor. To establish such a personalized TCR-T cell therapy, we comprehensively characterized T cells in tumor and its adjacent tissues by single-cell mRNA sequencing (scRNA-seq), TCR sequencing (TCR-seq) and in vitro neoantigen stimulation. Compared to bystander T cells circulating among tissues, Tas cells were characterized by tumor enrichment, tumor-specific clonal expansion and neoantigen specificity. We found that CXCL13 is a unique marker for both CD4+ and CD8+ Tas cells. Importantly, TCR-T cells expressing TCRs from Tas cells showed significant therapeutic effects on autologous patient-derived xenograft (PDX) tumors. Intratumoral Tas cell levels measured by CXCL13 expression precisely predicted the response to immune checkpoint blockade, indicating a critical role of Tas cells in the antitumor immunity. We further identified CD200 and ENTPD1 as surface markers for CD4+ and CD8+ Tas cells respectively, which enabled the isolation of Tas cells from tumor by Fluorescence Activating Cell Sorter (FACS) sorting. Overall, our results suggest that TCR-T cells engineered with Tas TCRs are a promising agent for personalized immunotherapy, and intratumoral Tas cell levels determine the response to immunotherapy.

Evaluation of the tumoricidal efficacy of adoptive cell transfer using hepatocellular carcinoma-derived organoids

Background

Tumor-derived organoid, namely tumoroid, can realistically retain the clinicopathologic features of original tumors even after long-term in vitro expansion. Here we develop this production methodology derived from hepatocellular carcinoma primary samples and generate a platform to evaluate the tumoricidal efficacy of autologous adoptive cell transfer including tumor infiltrating lymphocytes and peripheral blood lymphocytes.

Methods

Haematoxylin and eosin together with immunohistochemistry staining were employed to ascertain the morphologic and histological features of tumoroids and original tumors. Tumor killing ability of T cells was detected by lactate dehydrogenase assay and propidium iodide staining. In tumoroid xenograft mouse model, tumor volumes were measured and T cell functions were examined by flow cytometry technique.

Results

Four tumoroids with characteristics of poor differentiation and mild fibrosis were successfully established from fourteen hepatocellular carcinoma samples. More robust antitumor potential and hyper-functional phenotype of all four tumor infiltrating lymphocytes were observed compared to matched peripheral blood lymphocytes in coculture system. In tumoroid xenograft mouse models, however, only one patient-derived tumor infiltrating lymphocytes with the highest antitumor activity can bestow efficient tumor eradication.

Conclusions

Hepatocellular carcinoma tumoroid-based models could represent invaluable resources for evaluating the tumoricidal efficacy of autologous adoptive cell transfer. Tumor infiltrating lymphocytes should be a promising and yet-to-be-developed regimen to treat hepatocellular carcinoma.

Therapeutic DNA Vaccines against HPV-Related Malignancies: Promising Leads from Clinical Trials

In 2014 and 2021, two nucleic-acid vaccine candidates named MAV E2 and VGX-3100 completed phase III clinical trials in Mexico and U.S., respectively, for patients with human papillomavirus (HPV)-related, high-grade squamous intraepithelial lesions (HSIL). These well-tolerated but still unlicensed vaccines encode distinct HPV antigens (E2 versus E6+E7) to elicit cell-mediated immune responses; their clinical efficacy, as measured by HSIL regression or cure, was modest when compared with placebo or surgery (conization), but both proved highly effective in clearing HPV infection, which should help further optimize strategies for enhancing vaccine immunogenicity, toward an ultimate goal of preventing malignancies in millions of patients who are living with persistent, oncogenic HPV infection but are not expected to benefit from current, prophylactic vaccines. The major roadblocks to a highly efficacious and practical product remain challenging and can be classified into five categories: (i) getting the vaccines into the right cells for efficient expression and presentation of HPV antigens (fusion proteins or epitopes); (ii) having adequate coverage of oncogenic HPV types, beyond the current focus on HPV-16 and -18; (iii) directing immune protection to various epithelial niches, especially anogenital mucosa and upper aerodigestive tract where HPV-transformed cells wreak havoc; (iv) establishing the time window and vaccination regimen, including dosage, interval and even combination therapy, for achieving maximum efficacy; and (v) validating therapeutic efficacy in patients with poor prognosis because of advanced, recurrent or non-resectable malignancies. Overall, the room for improvements is still large enough that continuing efforts for research and development will very likely extend into the next decade.

T cell receptor (TCR) signaling in health and disease

Interaction of the T cell receptor (TCR) with an MHC-antigenic peptide complex results in changes at the molecular and cellular levels in T cells. The outside environmental cues are translated into various signal transduction pathways within the cell, which mediate the activation of various genes with the help of specific transcription factors. These signaling networks propagate with the help of various effector enzymes, such as kinases, phosphatases, and phospholipases. Integration of these disparate signal transduction pathways is done with the help of adaptor proteins that are non-enzymatic in function and that serve as a scaffold for various protein-protein interactions. This process aids in connecting the proximal to distal signaling pathways, thereby contributing to the full activation of T cells. This review provides a comprehensive snapshot of the various molecules involved in regulating T cell receptor signaling, covering both enzymes and adaptors, and will discuss their role in human disease.

Cancer immunotherapy: Challenges and limitations

Although cancer immunotherapy has taken center stage in mainstream oncology inducing complete and long-lasting tumor regression, only a subset of patients receiving treatment respond and others relapse after an initial response. Different tumor types respond differently, and even in cancer types that respond (hot tumors), we still observe tumors that are unresponsive (cold tumors), suggesting the presence of resistance. Hence, the development of intrinsic or acquired resistance is a big challenge for the cancer immunotherapy field. Resistance to immunotherapy, including checkpoint inhibitors, CAR-T cell therapy, oncolytic viruses, and recombinant cytokines arises due to cancer cells employing several mechanisms to evade immunosurveillance.

T Lymphocyte-Captured DNA Network for Localized Immunotherapy

The efficient isolation of immune cells with high purity and low cell damage is important for immunotherapy and remains highly challenging. We herein report a cell capture DNA network containing polyvalent multimodules for the specific isolation and in situ incubation of T lymphocytes (T-cells). Two ultralong DNA chains synthesized by an enzymatic amplification process were rationally designed to include functional multimodules as cell anchors and immune adjuvants. Mutually complementary sequences facilitated the formation of a DNA network and encapsulation of T-cells, as well as offering cutting sites of a restriction enzyme for the responsive release of T-cells and immune adjuvants. The purity of captured tumor-infiltrating T-cells reached 98%, and the viability of T-cells maintained ∼90%. The T-cells-containing DNA network was further administrated to a tumor lesion for localized immunotherapy. Our work provides a robust nanobiotechnology for efficient isolation of immune cells and other biological particles.

Cell Therapy: Types, Regulation, and Clinical Benefits

Cell therapy practices date back to the 19th century and continue to expand on investigational and investment grounds. Cell therapy includes stem cell- and non-stem cell-based, unicellular and multicellular therapies, with different immunophenotypic profiles, isolation techniques, mechanisms of action, and regulatory levels. Following the steps of their predecessor cell therapies that have become established or commercialized, investigational and premarket approval-exempt cell therapies continue to provide patients with promising therapeutic benefits in different disease areas. In this review article, we delineate the vast types of cell therapy, including stem cell-based and non-stem cell-based cell therapies, and create the first-in-literature compilation of the different "multicellular" therapies used in clinical settings. Besides providing the nuts and bolts of FDA policies regulating their use, we discuss the benefits of cell therapies reported in 3 therapeutic areas-regenerative medicine, immune diseases, and cancer. Finally, we contemplate the recent attention shift toward combined therapy approaches, highlighting the factors that render multicellular therapies a more attractive option than their unicellular counterparts.

Progress in research of tumor infiltrating lymphocytes in pancreatic cancer

The 5-year survival rate of pancreatic cancer is less than 5%, and the only available treatments, surgery, chemotherapy, and chemoradiation, have shown limited effectiveness. Therefore, alternative treatment strategies are urgently needed. In recent years, tumor infiltrating lymphocyte (TIL) therapy has shown promising successes in the treatment of some types of solid tumors because of its diverse TCR clonality, superior tumor-homing ability, and low off-target toxicity. The significant association between a high TIL density in pancreatic cancer tissue and a good clinical outcome and success of pancreatic cancer-specific TIL expansion ex vivo potentiates the rationality of the TIL therapy in pancreatic cancer. However, there are still many challenges ahead, such as neoantigen screening, rapid cell expansion, and low cytotoxicity. This article reviews the recent advances and limitations of TIL therapy in pancreatic cancer and discusses its future directions.

Cancer immunotherapies revisited: state of the art of conventional treatments and next-generation nanomedicines

Nowadays, the landscape of cancer treatments has broadened thanks to the clinical application of immunotherapeutics. After decades of failures, cancer immunotherapy represents an exciting alternative for those patients suffering from a wide variety of cancers, especially for those skin cancers, such as the early stages of melanoma. However, those cancers affecting internal organs still face a long way to success, because of the poor biodistribution of immunotherapies. Here, nanomedicine appears as a hopeful strategy to modulate the biodistribution aiming at target organ accumulation. In this way, efficacy will be improved, while reducing the side effects at the same time. In this review, we aim to highlight the most promising cancer immunotherapeutic strategies. From monoclonal antibodies and their traditional use as targeted therapies to their current use as immune checkpoint inhibitors; as well as adoptive cell transfer therapies; oncolytic viruses, and therapeutic cancer vaccination. Then, we aim to discuss the important role of nanomedicine to improve the performance of these immunotherapeutic tools to finally review the already marketed nanomedicine-based cancer immunotherapies.

Strategies to Overcome Failures in T-Cell Immunotherapies by Targeting PI3K-δ and -γ

PI3K-δ and PI3K-γ are critical regulators of T-cell differentiation, senescence, and metabolism. PI3K-δ and PI3K-γ signaling can contribute to T-cell inhibition via intrinsic mechanisms and regulation of suppressor cell populations, including regulatory T-cells and myeloid derived suppressor cells in the tumor. We examine an exciting new role for using selective inhibitors of the PI3K δ- and γ-isoforms as modulators of T-cell phenotype and function in immunotherapy. Herein we review the current literature on the implications of PI3K-δ and -γ inhibition in T-cell biology, discuss existing challenges in adoptive T-cell therapies and checkpoint blockade inhibitors, and highlight ongoing efforts and future directions to incorporate PI3K-δ and PI3K-γ as synergistic T-cell modulators in immunotherapy.

Natural Killer Cells and Type 1 Innate Lymphoid Cells in Hepatocellular Carcinoma: Current Knowledge and Future Perspectives

Natural killer (NK) cells and type 1 innate lymphoid cells (ILC1) are specific innate lymphoid cell subsets that are key for the detection and elimination of pathogens and cancer cells. In liver, while they share a number of characteristics, they differ in many features. These include their developmental pathways, tissue distribution, phenotype and functions. NK cells and ILC1 contribute to organ homeostasis through the production of key cytokines and chemokines and the elimination of potential harmful bacteria and viruses. In addition, they are equipped with a wide range of receptors, allowing them to detect “stressed cells’ such as cancer cells. Our understanding of the role of innate lymphoid cells in hepatocellular carcinoma (HCC) is growing owing to the development of mouse models, the progress in immunotherapeutic treatment and the recent use of scRNA sequencing analyses. In this review, we summarize the current understanding of NK cells and ILC1 in hepatocellular carcinoma and discuss future strategies to take advantage of these innate immune cells in anti-tumor immunity. Immunotherapies hold great promise in HCC, and a better understanding of the role and function of NK cells and ILC1 in liver cancer could pave the way for new NK cell and/or ILC1-targeted treatment.

Challenges and next steps in the advancement of immunotherapy: summary of the 2018 and 2020 National Cancer Institute workshops on cell-based immunotherapy for solid tumors

Cell-based immunotherapies have had remarkable success in the clinic, specifically in the treatment of hematologic malignancies. However, these strategies have had limited efficacy in patients with solid tumors. To better understand the challenges involved, the National Cancer Institute (NCI) convened an initial workshop with immuno-oncology thought leaders in December 2018 and a follow-up workshop in December 2020. The goals of the NCI workshops on cell-based immunotherapy for solid tumors were to discuss the current state of the field of cell-based immunotherapy, obtain insights into critical knowledge gaps, and identify ways in which NCI could facilitate progress. At both meetings, subjects emphasized four main types of challenges in further developing cell-based immunotherapy for patients with solid tumors: scientific, technical, clinical, and regulatory. The scientific barriers include selecting appropriate targets, ensuring adequate trafficking of cell therapy products to tumor sites, overcoming the immunosuppressive tumor microenvironment, and identifying appropriate models for these investigations. While mouse models may provide some useful data, the majority of those that are commonly used are immunodeficient and unable to fully recapitulate the immune response in patients. There is therefore a need for enhanced support of small early-phase human clinical studies, preferably with adaptive trial designs, to provide proof of concept for novel cell therapy approaches. Furthermore, the requirements for manufacturing, shipping, and distributing cell-based therapies present technical challenges and regulatory questions, which many research institutions are not equipped to address. Overall, workshop subjects identified key areas where NCI support might help the research community in driving forward innovation and clinical utility: 1) provide focused research support on topics such as tumor target selection, immune cell fitness and persistence, cell trafficking, and the immunosuppressive tumor microenvironment; 2) support the rapid translation of preclinical findings into proof of concept clinical testing, harmonize clinical trial regimens, and facilitate early trial data sharing (including negative results); 3) expand manufacturing support for cell therapies, including vectors and reagents, and provide training programs for technical staff; and 4) develop and share standard operating procedures for cell handling and analytical assays, and work with the Food and Drug Administration to harmonize product characterization specifications.

Bioinformatics-based analysis of the association between the A1-chimaerin (CHN1) gene and gastric cancer

Gastric cancer (GC) is one of the most common causes of cancer-related deaths worldwide and the identification of additional therapeutic targets and biomarkers has become vital. The A1-chimaerin (CHN1) gene encodes a ras-related protein that can be activated or inactivated by binding to GTP or GDP. The present study aimed to assess the expression of CHN1 in GC tissue and cells, to explore its relationship with GC progression, and to discover the potential mechanisms underlying these associations. The ONCOMINE database and The Cancer Genome Atlas (TCGA) were used to determine the transcriptional levels of CHN1 in GC. Western blot and immunohistochemistry were used for detecting protein expression. Correlations between CHN1 levels and the clinical outcomes of GC patients were examined using Kaplan–Meier and Cox regression analyses. Moreover, the CIBERSORT algorithm was used to estimate immune cell infiltration. In GC patients, CHN1 transcription and CHN1 protein expression were upregulated, and a high expression of CHN1 was remarkably linked to poor survival in GC patients. CHN1 expression was associated with immune infiltrates and this gene showed potential involvement in multiple cancer-related pathways. Furthermore, the expression of CHN1 was correlated with the immunotherapeutic response. Finally, our results indicated that the pro-carcinogenic role of CHN1 may involve DNA methylation. To our knowledge, this is the first report characterizing CHN1 expression in GC. Our results show that high CHN1 levels could be used as a clinical biomarker for poor prognosis and that CHN1 inhibitors may have potential as anti-cancer drugs.

Advancing therapy for osteosarcoma

Improving the survival of patients with osteosarcoma has long proved challenging, although the treatment of this disease is on the precipice of advancement. The increasing feasibility of molecular profiling together with the creation of both robust model systems and large, well-annotated tissue banks has led to an increased understanding of osteosarcoma biology. The historical invariability of survival outcomes and the limited number of agents known to be active in the treatment of this disease facilitate clinical trials designed to identify efficacious novel therapies using small cohorts of patients. In addition, trial designs will increasingly consider the genetic background of the tumour through biomarker-based patient selection, thereby enriching for clinical activity. Indeed, osteosarcoma cells are known to express a number of surface proteins that might be of therapeutic relevance, including B7-H3, GD2 and HER2, which can be targeted using antibody-drug conjugates and/or adoptive cell therapies. In addition, immune-checkpoint inhibition might augment the latter approach by helping to overcome the immunosuppressive tumour microenvironment. In this Review, we provide a brief overview of current osteosarcoma therapy before focusing on the biological insights from the molecular profiling and preclinical modelling studies that have opened new therapeutic opportunities in this disease.

Generation of neoantigen-specific T cells for adoptive cell transfer for treating head and neck squamous cell carcinoma

Adoptive cell therapy using TCR-engineered T cells (TCR-T cells) represents a promising strategy for treating relapsed and metastatic cancers. We previously established methods to identify neoantigen-specific TCRs based on patients’ PBMCs. However, in clinical practice isolation of PBMCs from advanced-stage cancer patients proves to be difficult. In this study, we substituted blood-derived T cells for tumor-infiltrating lymphocytes (TILs) and used an HLA-matched cell line of antigen-presenting cells (APCs) to replace autologous dendritic cells. Somatic mutations were determined in head and neck squamous cell carcinoma resected from two patients. HLA-A*02:01-restricted neoantigen libraries were constructed and transferred into HLA-matched APCs for stimulation of patient TILs. TCRs were isolated from reactive TIL cultures and functionality was tested using TCR- T cells in vitro and in vivo. To exemplify the screening approach, we identified the targeted neoantigen leading to recognition of the minigene construct that stimulated the strongest TIL response. Neoantigen peptides were used to load MHC-tetramers for T cell isolation and a TCR was identified targeting the KIAA1429_D1358E mutation. TCR-T cells were activated, exhibited cytotoxicity, and secreted cytokines in a dose-dependent manner, and only when stimulated with the mutant peptide. Furthermore, comparable to a neoantigen-specific TCR that was isolated from the patient’s PBMCs, KIAA1429_D1358E-specific TCR T cells destroyed human tumors in mice. The established protocol provides the required flexibility to methods striving to identify neoantigen-specific TCRs. By using an MHC-matched APC cell line and neoantigen-encoding minigene libraries, autologous TILs can be stimulated and screened when patient PBMCs and/or tumor material are not available anymore.

Abbreviations:

Head and neck squamous cell carcinoma (HNSCC); adoptive T cell therapy (ACT); T cell receptor (TCR); tumor-infiltrating lymphocytes (TIL); cytotoxic T lymphocyte (CTL); peripheral blood mononuclear cell (PBMC); dendritic cell (DC); antigen-presenting cells (APC)

Comparison of non-myeloablative lymphodepleting preconditioning regimens in patients undergoing adoptive T cell therapy

Background

Adoptive cell therapy with T cells genetically engineered to express a chimeric antigen receptor (CAR-T) or tumor-infiltrating T lymphocytes (TIL) demonstrates impressive clinical results in patients with cancer. Lymphodepleting preconditioning prior to cell infusion is an integral part of all adoptive T cell therapies. However, to date, there is no standardization and no data comparing different non-myeloablative (NMA) regimens.

Methods

In this study, we compared NMA therapies with different doses of cyclophosphamide or total body irradiation (TBI) in combination with fludarabine and evaluated bone marrow suppression and recovery, cytokine serum levels, clinical response and adverse events.

Results

We demonstrate that a cumulative dose of 120 mg/kg cyclophosphamide and 125 mg/m² fludarabine (120Cy/125Flu) and 60Cy/125Flu preconditioning were equally efficient in achieving deep lymphopenia and neutropenia in patients with metastatic melanoma, whereas absolute lymphocyte counts (ALCs) and absolute neutrophil counts were significantly higher following 200 cGyTBI/75Flu-induced NMA. Thrombocytopenia was most profound in 120Cy/125Flu patients. 30Cy/75Flu-induced preconditioning in patients with acute lymphoblastic leukemia resulted in a minor ALC decrease, had no impact on platelet counts and did not yield deep neutropenia. Following cell infusion, 120Cy/125Flu patients with objective tumor response had significantly higher ALC and significant lower inflammatory indexes, such as neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR). Receiver-operating characteristics curve analysis 7 days after cell infusion was performed to determine the cut-offs, which distinguish between responding and non-responding patients in the 120Cy/125Flu cohort. NLR≤1.79 and PLR≤32.7 were associated with clinical response and overall survival. Cytokine serum levels did not associate with clinical response in patients with TIL. Patients in the 120Cy/125Flu cohort developed significantly more acute NMA-related adverse events, including thrombocytopenia, febrile neutropenia and cardiotoxicity, and stayed significantly longer in hospital compared with the 60Cy/125Flu and TBI/75Flu cohorts.

Conclusions

Bone marrow depletion and recovery were equally affected by 120Cy/125Flu and 60Cy/125Flu preconditioning; however, toxicity and consequently duration of hospitalization were significantly lower in the 60Cy/125Flu cohort. Patients in the 30Cy/75Flu and TBI/75Flu groups rarely developed NMA-induced adverse events; however, both regimens were not efficient in achieving deep bone marrow suppression. Among the regimens, 60Cy/125Flu preconditioning seems to achieve maximum effect with minimum toxicity.

Overview of Cellular Immunotherapies within Transfusion Medicine for the Treatment of Malignant Diseases

Over the years, transfusion medicine has developed into a broad, multidisciplinary field that covers different clinical patient services such as apheresis technology and the development of stem cell transplantation. Recently, the discipline has found a niche in development and production of advanced therapy medicinal products (ATMPs) for immunotherapy and regenerative medicine purposes. In clinical trials, cell-based immunotherapies have shown encouraging results in the treatment of multiple cancers and autoimmune diseases. However, there are many parameters such as safety, a high level of specificity, and long-lasting efficacy that still need to be optimized to maximize the potential of cell-based immunotherapies. Thus, only a few have gained FDA approval, while the majority of them are studied in the context of investigator-initiated trials (IITs), where modern, academically oriented transfusion centers can play an important role. In this review, we summarize existing and contemporary cellular immunotherapies, which are already a part of modern transfusion medicine or are likely to become so in the future.

Lymphocyte expansion in bioreactors: upgrading adoptive cell therapy

Bioreactors are essential tools for the development of efficient and high-quality cell therapy products. However, their application is far from full potential, holding several challenges when reconciling the complex biology of the cells to be expanded with the need for a manufacturing process that is able to control cell growth and functionality towards therapy affordability and opportunity. In this review, we discuss and compare current bioreactor technologies by performing a systematic analysis of the published data on automated lymphocyte expansion for adoptive cell therapy. We propose a set of requirements for bioreactor design and identify trends on the applicability of these technologies, highlighting the specific challenges and major advancements for each one of the current approaches of expansion along with the opportunities that lie in process intensification. We conclude on the necessity to develop targeted solutions specially tailored for the specific stimulation, supplementation and micro-environmental needs of lymphocytes’ cultures, and the benefit of applying knowledge-based tools for process control and predictability.

Role of immunotherapy in gastro-enteropancreatic neuroendocrine neoplasms (gep-nens): Current advances and future directions

Neuroendocrine neoplasms (NENs) are heterogeneous tumours originating from neuroendocrine cells (Pearse & Polak, Gut, 1971, 12,783). They were once considered as rare tumours, although their annual incidence has increased significantly and now exceeds seven cases in 100 000 in the USA (Dasari, et al., JAMA oncology, 2017, 3, 1335). They are a group of highly diverse neoplasms and can be classified into the spectrum of well-differentiated neuroendocrine tumours to poorly differentiated neuroendocrine carcinomas. This is entirely based on the tumour differentiation and grade (low, intermediate, high), which is determined by the Ki-67/mitotic index. The lower grades (G1/2) of the well-differentiated group are characterised by a relative indolent clinical course and the ability to secrete a variety of peptide hormones (Kloppel, Visceral medicine, 2017, 33, 324). Higher grades and poorly differentiated tumours tend to be more aggressive and have limited therapeutic options (Sorbye et al., Neuroendocrinology, 2019, 108, 54). In the modern era of immuno-oncology, immune checkpoint inhibitors (ICPIs) that target programmed cell death 1 (pembrolizumab, nivolumab), programmed cell death-ligand1 (avelumab, atezolizumab and durvalumab) or cytotoxic T-lymphocyte-associated protein 4 (ipilimumab) have revolutionised the management of many solid tumours. In patients with gastro-enteropancreatic (GEP)-NENs, there is a limited data regarding the role of ICPIs either as a single agent or in combination regimens. Here, we review the current advances for ICPIs and where they fit in the management of GEP-NENs.

Quantifying the limits of CAR T-cell delivery in mice and men

CAR (Chimeric Antigen Receptor) T cells have demonstrated clinical success for the treatment of multiple lymphomas and leukaemias, but not for various solid tumours, despite promising data from murine models. Lower effective CAR T-cell delivery rates to human solid tumours compared to haematological malignancies in humans and solid tumours in mice might partially explain these divergent outcomes. We used anatomical and physiological data for human and rodent circulatory systems to calculate the typical perfusion of healthy and tumour tissues, and estimated the upper limits of immune cell delivery rates across different organs, tumour types and species. Estimated maximum delivery rates were up to 10 000-fold greater in mice than humans yet reported CAR T-cell doses are typically only 10-100-fold lower in mice, suggesting that the effective delivery rates of CAR T cells into tumours in clinical trials are far lower than in corresponding mouse models. Estimated delivery rates were found to be consistent with published positron emission tomography data. Results suggest that higher effective human doses may be needed to drive efficacy comparable to mouse solid tumour models, and that lower doses should be tested in mice. We posit that quantitation of species and organ-specific delivery and homing of engineered T cells will be key to unlocking their potential for solid tumours.

The current landscape of single-cell transcriptomics for cancer immunotherapy

Immunotherapies such as immune checkpoint blockade and adoptive cell transfer have revolutionized cancer treatment, but further progress is hindered by our limited understanding of tumor resistance mechanisms. Emerging technologies now enable the study of tumors at the single-cell level, providing unprecedented high-resolution insights into the genetic makeup of the tumor microenvironment and immune system that bulk genomics cannot fully capture. Here, we highlight the recent key findings of the use of single-cell RNA sequencing to deconvolute heterogeneous tumors and immune populations during immunotherapy. Single-cell RNA sequencing has identified new crucial factors and cellular subpopulations that either promote tumor progression or leave tumors vulnerable to immunotherapy. We anticipate that the strategic use of single-cell analytics will promote the development of the next generation of successful, rationally designed immunotherapeutics.

Precision Tools in Immuno-Oncology: Synthetic Gene Circuits for Cancer Immunotherapy

Engineered mammalian cells for medical purposes are becoming a clinically relevant reality thanks to advances in synthetic biology that allow enhanced reliability and safety of cell-based therapies. However, their application is still hampered by challenges including time-consuming design-and-test cycle iterations and costs. For example, in the field of cancer immunotherapy, CAR-T cells targeting CD19 have already been clinically approved to treat several types of leukemia, but their use in the context of solid tumors is still quite inefficient, with additional issues related to the adequate quality control for clinical use. These limitations can be overtaken by innovative bioengineering approaches currently in development. Here we present an overview of recent synthetic biology strategies for mammalian cell therapies, with a special focus on the genetic engineering improvements on CAR-T cells, discussing scenarios for the next generation of genetic circuits for cancer immunotherapy.

Adaptive T cell immunotherapy in cancer

Impaired tumor-specific effector T cells contribute to tumor progression and unfavorable clinical outcomes. As a compensatory T cell-dependent cancer immunoediting strategy, adoptive T cell therapy (ACT) has achieved encouraging therapeutic results, and this strategy is now on the center stage of cancer treatment and research. ACT involves the ex vivo stimulation and expansion of tumor-infiltrating lymphocytes (TILs) with inherent tumor reactivity or T cells that have been genetically modified to express the cognate chimeric antigen receptor or T cell receptor (CAR/TCR), followed by the passive transfer of these cells into a lymphodepleted host. Primed T cells must provide highly efficient and long-lasting immune defense against transformed cells during ACT. Anin-depth understanding of the basic mechanisms of these living drugs can help us improve upon current strategies and design better next-generation T cell-based immunotherapies. From this perspective, we provide an overview of current developments in different ACT strategies, with a focus on frontier clinical trials that offer a proof of principle. Meanwhile, insights into the determinants of ACT are discussed, which will lead to more rational, potent and widespread applications in the future.

PTEN Function at the Interface between Cancer and Tumor Microenvironment: Implications for Response to Immunotherapy

Mounting preclinical and clinical evidence indicates that rewiring the host immune system in favor of an antitumor microenvironment achieves remarkable clinical efficacy in the treatment of many hematological and solid cancer patients. Nevertheless, despite the promising development of many new and interesting therapeutic strategies, many of these still fail from a clinical point of view, probably due to the lack of prognostic and predictive biomarkers. In that respect, several data shed new light on the role of the tumor suppressor phosphatase and tensin homolog on chromosome 10 (PTEN) in affecting the composition and function of the tumor microenvironment (TME) as well as resistance/sensitivity to immunotherapy. In this review, we summarize current knowledge on PTEN functions in different TME compartments (immune and stromal cells) and how they can modulate sensitivity/resistance to different immunological manipulations and ultimately influence clinical response to cancer immunotherapy.

Engineering the Bridge between Innate and Adaptive Immunity for Cancer Immunotherapy: Focus on γδ T and NK Cells

Most studies on genetic engineering technologies for cancer immunotherapy based on allogeneic donors have focused on adaptive immunity. However, the main limitation of such approaches is that they can lead to severe graft-versus-host disease (GvHD). An alternative approach would bolster innate immunity by relying on the natural tropism of some subsets of the innate immune system, such as γδ T and natural killer (NK) cells, for the tumor microenvironment and their ability to kill in a major histocompatibility complex (MHC)-independent manner. γδ T and NK cells have the unique ability to bridge innate and adaptive immunity while responding to a broad range of tumors. Considering these properties, γδ T and NK cells represent ideal sources for developing allogeneic cell therapies. Recently, significant efforts have been made to exploit the intrinsic anti-tumor capacity of these cells for treating hematologic and solid malignancies using genetic engineering approaches such as chimeric antigen receptor (CAR) and T cell receptor (TCR). Here, we review over 30 studies on these two approaches that use γδ T and NK cells in adoptive cell therapy (ACT) for treating cancer. Based on those studies, we propose several promising strategies to optimize the clinical translation of these approaches.

Immunotherapies and Combination Strategies for Immuno-Oncology

The advent of novel immunotherapies in the treatment of cancers has dramatically changed the landscape of the oncology field. Recent developments in checkpoint inhibition therapies, tumor-infiltrating lymphocyte therapies, chimeric antigen receptor T cell therapies, and cancer vaccines have shown immense promise for significant advancements in cancer treatments. Immunotherapies act on distinct steps of immune response to augment the body's natural ability to recognize, target, and destroy cancerous cells. Combination treatments with immunotherapies and other modalities intend to activate immune response, decrease immunosuppression, and target signaling and resistance pathways to offer a more durable, long-lasting treatment compared to traditional therapies and immunotherapies as monotherapies for cancers. This review aims to briefly describe the rationale, mechanisms of action, and clinical efficacy of common immunotherapies and highlight promising combination strategies currently approved or under clinical development. Additionally, we will discuss the benefits and limitations of these immunotherapy approaches as monotherapies as well as in combination with other treatments.

T-Cell Receptor-Based Immunotherapy for Hematologic Malignancies

Adoptive immunotherapy with engineered T cells is at the forefront of cancer treatment. T cells can be engineered to express T-cell receptors (TCRs) specific for tumor-associated antigens (TAAs) derived from intracellular or cell surface proteins. T cells engineered with TCRs (TCR-T) allow for targeting diverse types of TAAs, including proteins overexpressed in malignant cells, those with lineage-restricted expression, cancer-testis antigens, and neoantigens created from abnormal, malignancy-restricted proteins. Minor histocompatibility antigens can also serve as TAAs for TCR-T to treat relapsed hematologic malignancies after allogeneic hematopoietic cell transplantation. Moreover, TCR constructs can be modified to improve safety and enhance function and persistence of TCR-T. Transgenic T-cell receptor therapies targeting 3 different TAAs are in early-phase clinical trials for treatment of hematologic malignancies. Preclinical studies of TCR-T specific for many other TAAs are underway and offer great promise as safe and effective therapies for a wide range of cancers.