Antitumor effect of an adeno-associated virus expressing apolipoprotein A-1 fused to interferon alpha in an interferon alpha-resistant murine tumor model

Reconfiguring the immune system to target cancer: Therapies based on T cells, cytokines, and vaccines

Over the years, extensive research has been dedicated to performing in-depth analysis of cancer to uncover the intricate details of its nature - including the types of cancer, causative agents, stimulators of disease progression, factors contributing to poor prognosis, and efficient therapies to restrict the metastatic aggressiveness. This chapter highlights the mechanisms through which different arms of the host immune system - namely cytokines, lymphocytes, antigen-presenting cells (APCs) -can be mobilized to eradicate cancer. Most malignant tumors are either poorly immunogenic, or are harbored in a highly immuno-suppressive microenvironment. This is why reinforcing the host's anti-tumor defenses, through infusion of pro-inflammatory cytokines, tumor antigen-loaded APCs, and anti-tumor cytotoxic cells has emerged as a viable treatment option against cancer. The chapter also highlights the ongoing preclinical and clinical studies in different malignancies and the outcome of various therapies. Although these methods are not foolproof, and antigen escape variants can still evade or develop resistance to customized therapies, they achieve disease stabilization in several cases when conventional treatments fail. In many instances, combination therapies involving cytokines, T cells, and vaccinations prove more effective than monotherapies. The limitations of the current therapies are also discussed, along with ongoing modifications aimed at improving efficacy.

Engineering interferons for cancer immunotherapy

Interferons are a family of cytokines that are famously known for their involvement in innate and adaptive immunity. Type I interferons (IFNs) exert pleiotropic effects on various immune cells and contribute to tumor-intrinsic and extrinsic mechanisms. Their pleiotropic effects and ubiquitous expression on nucleated cells have made them attractive candidates for cytokine engineering to deliver to largely immunosuppressive tumors. Type III interferons were believed to play overlapping roles with type I IFNs because they share a similar signaling pathway and induce similar transcriptional programs. However, type III IFNs are unique in their cell specific receptor expression and their antitumor activity is specific to a narrow range of cell types. Thus, type III IFN based therapies may show reduced toxic side effects compared with type I IFN based treatment. In this review, we focus on the development of IFN-based therapeutics used to treat different tumors. We highlight how the development in cytokine engineering has allowed for efficient delivery of type I and type III IFNs to tumor sites and look ahead to the obstacles that are still associated with IFN-based therapies before they can be fully and safely integrated into clinical settings.

Recent advances in various adeno-associated viruses (AAVs) as gene therapy agents in hepatocellular carcinoma

Primary liver cancer, which is scientifically referred to as hepatocellular carcinoma (HCC), is a significant concern in the field of global health. It has been demonstrated that conventional chemotherapy, chemo-hormonal therapy, and conformal radiotherapy are ineffective against HCC. New therapeutic approaches are thus urgently required. Identifying single or multiple mutations in genes associated with invasion, metastasis, apoptosis, and growth regulation has resulted in a more comprehensive comprehension of the molecular genetic underpinnings of malignant transformation, tumor advancement, and host interaction. This enhanced comprehension has notably propelled the development of novel therapeutic agents. Therefore, gene therapy (GT) holds great promise for addressing the urgent need for innovative treatments in HCC. However, the complexity of HCC demands precise and effective therapeutic approaches. The adeno-associated virus (AAV) distinctive life cycle and ability to persistently infect dividing and nondividing cells have rendered it an alluring vector. Another appealing characteristic of the wild-type virus is its evident absence of pathogenicity. As a result, AAV, a vector that lacks an envelope and can be modified to transport DNA to specific cells, has garnered considerable interest in the scientific community, particularly in experimental therapeutic strategies that are still in the clinical stage. AAV vectors emerge as promising tools for HCC therapy due to their non-immunogenic nature, efficient cell entry, and prolonged gene expression. While AAV-mediated GT demonstrates promise across diverse diseases, the current absence of ongoing clinical trials targeting HCC underscores untapped potential in this context. Furthermore, gene transfer through hepatic AAV vectors is frequently facilitated by GT research, which has been propelled by several congenital anomalies affecting the liver. Notwithstanding the enthusiasm associated with this notion, recent discoveries that expose the integration of the AAV vector genome at double-strand breaks give rise to apprehensions regarding their enduring safety and effectiveness. This review explores the potential of AAV vectors as versatile tools for targeted GT in HCC. In summation, we encapsulate the multifaceted exploration of AAV vectors in HCC GT, underlining their transformative potential within the landscape of oncology and human health.

Type I and II interferon signaling in colorectal cancer liver metastasis

Metastatic colorectal cancer is one of the leading causes of cancer-related deaths worldwide. Traditional chemotherapy extended the lifespan of cancer patients by only a few months, but targeted therapies and immunotherapy prolonged survival and led to long-term remissions in some cases. Type I and II interferons have direct pro-apoptotic and anti-proliferative effects on cancer cells and stimulate anti-cancer immunity. As a result, interferon production by cells in the tumor microenvironment is in the spotlight of immunotherapies as it affects the responses of anti-cancer immune cells. However, promoting effects of interferons on colorectal cancer metastasis have also been reported. Here we summarize our knowledge about pro- and anti-metastatic effects of type I and II interferons in colorectal cancer liver metastasis and discuss possible therapeutic implications.

Overcoming the limitations of cytokines to improve cancer therapy

Cytokines are pleiotropic soluble proteins used by immune cells to orchestrate a coordinated response against pathogens and malignancies. In cancer immunotherapy, cytokine-based drugs can be developed potentiating pro-inflammatory cytokines or blocking immunosuppressive cytokines. However, the complexity of the mechanisms of action of cytokines requires the use of biotechnological strategies to minimize systemic toxicity, while potentiating the antitumor response. Sequence mutagenesis, fusion proteins and gene therapy strategies are employed to enhance the half-life in circulation, target the desired bioactivity to the tumor microenvironment, and to optimize the therapeutic window of cytokines. In this review, we provide an overview of the different strategies currently being pursued in pre-clinical and clinical studies to make the most of cytokines for cancer immunotherapy.

Current Trends in Cancer Immunotherapy

The search for an effective drug to treat oncological diseases, which have become the main scourge of mankind, has generated a lot of methods for studying this affliction. It has also become a serious challenge for scientists and clinicians who have needed to invent new ways of overcoming the problems encountered during treatments, and have also made important discoveries pertaining to fundamental issues relating to the emergence and development of malignant neoplasms. Understanding the basics of the human immune system interactions with tumor cells has enabled new cancer immunotherapy strategies. The initial successes observed in immunotherapy led to new methods of treating cancer and attracted the attention of the scientific and clinical communities due to the prospects of these methods. Nevertheless, there are still many problems that prevent immunotherapy from calling itself an effective drug in the fight against malignant neoplasms. This review examines the current state of affairs for each immunotherapy method, the effectiveness of the strategies under study, as well as possible ways to overcome the problems that have arisen and increase their therapeutic potentials.

Towards Clinical Implementation of Adeno-Associated Virus (AAV) Vectors for Cancer Gene Therapy: Current Status and Future Perspectives

Adeno-associated virus (AAV) vectors have gained tremendous attention as in vivo delivery systems in gene therapy for inherited monogenetic diseases. First market approvals, excellent safety data, availability of large-scale production protocols, and the possibility to tailor the vector towards optimized and cell-type specific gene transfer offers to move from (ultra) rare to common diseases. Cancer, a major health burden for which novel therapeutic options are urgently needed, represents such a target. We here provide an up-to-date overview of the strategies which are currently developed for the use of AAV vectors in cancer gene therapy and discuss the perspectives for the future translation of these pre-clinical approaches into the clinic.

Treatment of Experimental Autoimmune Encephalomyelitis by Sustained Delivery of Low-Dose IFN-α

Multiple sclerosis (MS) is a chronic autoimmune disease with no curative treatment. The immune regulatory properties of type I IFNs have led to the approval of IFN-β for the treatment of relapsing-remitting MS. However, there is still an unmet need to improve the tolerability and efficacy of this therapy. In this work, we evaluated the sustained delivery of IFN-α1, either alone or fused to apolipoprotein A-1 by means of an adeno-associated viral (AAV) system in the mouse model of myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis. These in vivo experiments demonstrated the prophylactic and therapeutic efficacy of the AAV-IFN-α or AAV-IFN-α fused to apolipoprotein A-1 vectors in experimental autoimmune encephalomyelitis, even at low doses devoid of hematological or neurologic toxicity. The sustained delivery of such low-dose IFN-α resulted in immunomodulatory effects, consisting of proinflammatory monocyte and T regulatory cell expansion. Moreover, encephalitogenic T lymphocytes from IFN-α-treated mice re-exposed to the myelin oligodendrocyte glycoprotein peptide in vitro showed a reduced proliferative response and cytokine (IL-17A and IFN-γ) production, in addition to upregulation of immunosuppressive molecules, such as IL-10, IDO, or PD-1. In conclusion, the results of the present work support the potential of sustained delivery of low-dose IFN-α for the treatment of MS and likely other T cell-dependent chronic autoimmune disorders.

Production and use of adeno-associated virus vectors as tools for cancer immunotherapy

Recombinant adeno-associated viruses (rAAVs) are attractive tools for research in cancer immunotherapy. A single administration of an AAV vector in tumor mouse models induces a progressive increase in transgene expression which reaches a plateau 1 or 2 weeks after administration. The rAAV is then able to maintain the expression of the immunostimulatory transgene. Thus, the use of these vectors obviates the need for frequent administrations of the therapeutic protein to achieve the antitumor effect. The long-term expression of AAV vectors can be exploited for the evaluation of the antitumor activity of immune-enhancing proteins. Most preclinical studies have focused on the expression of cytokines and on the induction of immune responses elicited by tumor-associated antigens expressed by rAAVs. Notwithstanding, rAAVs may not be suitable for immunostimulatory proteins that require high and/or immediate expression. In this chapter, we review a feasible, reliable and detailed protocol to produce and purify AAV vectors as a tool for cancer immunotherapy strategies.

Cytokines in clinical cancer immunotherapy

Cytokines are soluble proteins that mediate cell-to-cell communication. Based on the discovery of the potent anti-tumour activities of several pro-inflammatory cytokines in animal models, clinical research led to the approval of recombinant interferon-alpha and interleukin-2 for the treatment of several malignancies, even if efficacy was only modest. These early milestones in immunotherapy have been followed by the recent addition to clinical practice of antibodies that inhibit immune checkpoints, as well as chimeric antigen receptor T cells. A renewed interest in the anti-tumour properties of cytokines has led to an exponential increase in the number of clinical trials that explore the safety and efficacy of cytokine-based drugs, not only as single agents, but also in combination with other immunomodulatory drugs. These second-generation drugs under clinical development include known molecules with novel mechanisms of action, new targets, and fusion proteins that increase half-life and target cytokine activity to the tumour microenvironment or to the desired effector immune cells. In addition, the detrimental activity of immunosuppressive cytokines can be blocked by antagonistic antibodies, small molecules, cytokine traps or siRNAs. In this review, we provide an overview of the novel trends in the cytokine immunotherapy field that are yielding therapeutic agents for clinical trials.

New trends in antitumor vaccines in melanoma

Antitumor therapeutic vaccines aim at priming an effector immune response able to recognize and kill tumor cells. Antitumor vaccines are composed of at least two main components: the tumor antigens and the adjuvant. Metastatic advanced melanoma has been a model disease to test novel advances in vaccine design due to the intrinsic immunogenicity of this tumor and the accessibility to melanoma lesions to monitor the immune response. In spite of a large number of clinical trials, clinical benefit remains elusive. The clinical success of monoclonal antibodies targeting immune check-points has renewed interest in novel vaccine strategies such as personalized neoantigen-based vaccines.