Doubling the blockade for melanoma immunotherapy

Cell Identity and Spatial Distribution of PD-1/PD-L1 Blockade Responders

The programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) axis inhibits T cell activity, impairing anti-tumor immunity. Blocking this axis with therapeutic antibodies is one of the most promising anti-tumor immunotherapies. It has long been recognized that PD-1/PD-L1 blockade reinvigorates exhausted T (TEX) cells already present in the tumor microenvironment (TME). However, recent advancements in high-throughput gene sequencing and bioinformatic tools have provided researchers with a more granular and dynamic insight into PD-1/PD-L1 blockade-responding cells, extending beyond the TME and TEX populations. This review provides an update on the cell identity, spatial distribution, and treatment-induced spatiotemporal dynamics of PD-1/PD-L1 blockade responders. It also provides a synopsis of preliminary reports of potential PD-1/PD-L1 blockade responders other than T cells to depict a panoramic picture. Important questions to answer in further studies and the translational and clinical potential of the evolving understandings are also discussed.

Nanoparticles: Properties and Applications in Cancer Immunotherapy

BACKGROUND

Tumours are no longer regarded as isolated masses of aberrantly proliferating epithelial cells. Rather, their properties depend on complex interactions between epithelial cancer cells and the surrounding stromal compartment within the tumour microenvironment. In particular, leukocyte infiltration plays a role in controlling tumour development and is now considered one of the hallmarks of cancer. Thus, in the last few years, immunotherapy has become a promising strategy to fight cancer, as its goal is to reprogram or activate antitumour immunity to kill tumour cells, without damaging the normal cells and provide long-lasting results where other therapies fail. However, the immune-related adverse events due to the low specificity in tumour cell targeting, strongly limit immunotherapy efficacy. In this regard, nanomedicine offers a platform for the delivery of different immunotherapeutic agents specifically to the tumour site, thus increasing efficacy and reducing toxicity. Indeed, playing with different material types, several nanoparticles can be formulated with different shape, charge, size and surface chemical modifications making them the most promising platform for biomedical applications.

AIM

In this review, we will summarize the different types of cancer immunotherapy currently in clinical trials or already approved for cancer treatment. Then, we will focus on the most recent promising strategies to deliver immunotherapies directly to the tumour site using nanoparticles.

CONCLUSION

Nanomedicine seems to be a promising approach to improve the efficacy of cancer immunotherapy. However, additional investigations are needed to minimize the variables in the production processes in order to make nanoparticles suitable for clinical use.

Trial Watch: Oncolytic viro-immunotherapy of hematologic and solid tumors

Oncolytic viruses selectively target and kill cancer cells in an immunogenic fashion, thus supporting the establishment of therapeutically relevant tumor-specific immune responses. In 2015, the US Food and Drug Administration (FDA) approved the oncolytic herpes simplex virus T-VEC for use in advanced melanoma patients. Since then, a plethora of trials has been initiated to assess the safety and efficacy of multiple oncolytic viruses in patients affected with various malignancies. Here, we summarize recent preclinical and clinical progress in the field of oncolytic virotherapy.

Trial watch: DNA-based vaccines for oncological indications

DNA-based vaccination is a promising approach to cancer immunotherapy. DNA-based vaccines specific for tumor-associated antigens (TAAs) are indeed relatively simple to produce, cost-efficient and well tolerated. However, the clinical efficacy of DNA-based vaccines for cancer therapy is considerably limited by central and peripheral tolerance. During the past decade, considerable efforts have been devoted to the development and characterization of novel DNA-based vaccines that would circumvent this obstacle. In this setting, particular attention has been dedicated to the route of administration, expression of modified TAAs, co-expression of immunostimulatory molecules, and co-delivery of immune checkpoint blockers. Here, we review preclinical and clinical progress on DNA-based vaccines for cancer therapy.

Trial watch: Immune checkpoint blockers for cancer therapy

Immune checkpoint blockers (ICBs) are literally revolutionizing the clinical management of an ever more diversified panel of oncological indications. Although considerable attention persists around the inhibition of cytotoxic T lymphocyte-associated protein 4 (CTLA4) and programmed cell death 1 (PDCD1, best known as PD-1) signaling, several other co-inhibitory T-cell receptors are being evaluated as potential targets for the development of novel ICBs. Moreover, substantial efforts are being devoted to the identification of biomarkers that reliably predict the likelihood of each patient to obtain clinical benefits from ICBs in the absence of severe toxicity. Tailoring the delivery of specific ICBs or combinations thereof to selected patient populations in the context of precision medicine programs constitutes indeed a major objective of the future of ICB-based immunotherapy. Here, we discuss recent preclinical and clinical advances on the development of ICBs for oncological indications.

Trial Watch: Adoptively transferred cells for anticancer immunotherapy

Immunotherapies aimed at strengthening immune effector responses against malignant cells are growing at exponential rates. Alongside, the impressive benefits obtained by patients with advanced melanoma who received adoptively transferred tumor-infiltrating lymphocytes (TILs) have encouraged the scientific community to pursue adoptive cell transfer (ACT)-based immunotherapy. ACT involves autologous or allogenic effector lymphocytes that are generally obtained from the peripheral blood or resected tumors, expanded and activated ex vivo, and administered to lymphodepleted patients. ACT may be optionally associated with chemo- and/or immunotherapeutics, with the overall aim of enhancing the proliferation, persistence and functionality of infused cells, as well as to ensure their evolution in an immunological permissive local and systemic microenvironment. In addition, isolated lymphocytes can be genetically engineered to endow them with the ability to target a specific tumor-associated antigen (TAA), to increase their lifespan, and/or to reduce their potential toxicity. The infusion of chimeric antigen receptor (CAR)-expressing cytotoxic T lymphocytes redirected against CD19 has shown promising clinical efficacy in patients with B-cell malignancies. Accordingly, the US Food and Drug Administration (FDA) has recently granted 'breakthrough therapy' designation to a CAR-based T-cell therapy (CTL019) for patients with B-cell malignancies. Considerable efforts are now being devoted to the development of efficient ACT-based immunotherapies for non-hematological neoplasms. In this Trial Watch, we summarize recent clinical advances on the use of ACT for oncological indications.

Function and Clinical Implications of Long Non-Coding RNAs in Melanoma

Metastatic melanoma is the most deadly type of skin cancer. Despite the success of immunotherapy and targeted agents, the majority of patients experience disease recurrence upon treatment and die due to their disease. Long non-coding RNAs (lncRNAs) are a new subclass of non-protein coding RNAs involved in (epigenetic) regulation of cell growth, invasion, and other important cellular functions. Consequently, recent research activities focused on the discovery of these lncRNAs in a broad spectrum of human diseases, especially cancer. Additional efforts have been undertaken to dissect the underlying molecular mechanisms employed by lncRNAs. In this review, we will summarize the growing evidence of deregulated lncRNA expression in melanoma, which is linked to tumor growth and progression. Moreover, we will highlight specific molecular pathways and modes of action for some well-studied lncRNAs and discuss their potential clinical implications.

Immune biomarkers for prognosis and prediction of responses to immune checkpoint blockade in cutaneous melanoma

Existing clinical, anatomopathological and molecular biomarkers fail to reliably predict the prognosis of cutaneous melanoma. Biomarkers for determining which patients receive adjuvant therapies are needed. The emergence of new technologies and the discovery of new immune populations with different prognostic values allow the immune network in the tumor to be better understood. Importantly, new molecules identified and expressed by immune cells have been shown to reduce the antitumor immune efficacy of therapies, prompting researchers to develop antibodies targeting these so-called "immune checkpoints", which have now entered the oncotherapeutic armamentarium.