Principles and current clinical landscape of NK cell engaging bispecific antibody against cancer

Natural killer cell engagers: From bi-specific to tri-specific and tetra-specific engagers for enhanced cancer immunotherapy

Natural killer cell engagers (NKCEs) are a specialised subset of antibodies capable of simultaneously targeting endogenous NK cells and tumour cells, generating precise and effective cytolytic responses against cancer. This review systematically explores NK engagers as a rising star in NK-mediated immunotherapy, specifically focusing on multi-specific engagers. It examines the diverse configuration of NKCEs and how certain biologics could be employed to boost NK activity, including activating receptor engagement and cytokine incorporation. Some challenges and future perspectives of current NKCEs therapy are also discussed, including optimising pharmacokinetics, addressing the immunosuppressive tumour microenvironment and exploring potential combinatorial approaches. By offering an in-depth analysis of the current landscape and future trajectories of multi-specific NKCEs in cancer treatment, this review serves as a valuable resource for understanding this promising field of immunotherapy.

HIGHLIGHTS

Innovative NKCEs: NK cell engagers (NKCEs) represent a promising new class of immunotherapeutics targeting tumours by activating NK cells. Multi-specific formats: The transition from bi-specific to multi-specific NKCEs enhances their versatility and therapeutic efficacy.

MECHANISMS OF ACTION

NKCEs have the potential to improve NK cell activation by engaging activating receptors and incorporating cytokines.

CLINICAL POTENTIAL

Current clinical trials demonstrate the safety and efficacy of various NKCEs across different cancer types. Future research directions: Optimising NKCE designs and exploring combination therapies are essential for overcoming challenges in cancer treatment.

Mechanistic regulation of HERV activation in tumors and implications for translational research in oncology

Transcription of distinct loci of human endogenous retroviruses (HERVs) and in some cases, translation of these transcripts have been consistently observed in many types of cancer. It is still debated whether HERV activation serves as a trigger for carcinogenesis or rather occurs as a consequence of epigenetic alterations and other molecular sequelae that characterize cellular transformation. Here we review the known molecular and epigenetic mechanisms of HERV activation in cancer cells as well as its potential contribution to carcinogenesis. Further, we describe the use of HERV expression in cancer diagnostic and characterize the potential of HERV-derived antigens to serve as novel targets for cancer immunotherapy. We believe this review, which summarizes both what is known as well as unknown in this rapidly developing field, will boost interest in research on the therapeutic potential of targeting HERV elements in tumors and the impact of HERV activation in oncogenesis.

Potentiation of natural killer cells to overcome cancer resistance to NK cell-based therapy and to enhance antibody-based immunotherapy

Natural killer (NK) cells are cellular components of the innate immune system that can recognize and suppress the proliferation of cancer cells. NK cells can eliminate cancer cells through direct lysis, by secreting perforin and granzymes, or through antibody-dependent cell-mediated cytotoxicity (ADCC). ADCC involves the binding of the Fc gamma receptor IIIa (CD16), present on NK cells, to the constant region of an antibody already bound to cancer cells. Cancer cells use several mechanisms to evade antitumor activity of NK cells, including the accumulation of inhibitory cytokines, recruitment and expansion of immune suppressor cells such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), modulation of ligands for NK cells receptors. Several strategies have been developed to enhance the antitumor activity of NK cells with the goal of overcoming cancer cells resistance to NK cells. The three main strategies to engineer and boost NK cells cytotoxicity include boosting NK cells with modulatory cytokines, adoptive NK cell therapy, and the employment of engineered NK cells to enhance antibody-based immunotherapy. Although the first two strategies improved the efficacy of NK cell-based therapy, there are still some limitations, including immune-related adverse events, induction of immune-suppressive cells and further cancer resistance to NK cell killing. One strategy to overcome these issues is the combination of monoclonal antibodies (mAbs) that mediate ADCC and engineered NK cells with potentiated anti-cancer activity. The advantage of using mAbs with ADCC activity is that they can activate NK cells, but also favor the accumulation of immune effector cells to the tumor microenvironment (TME). Several clinical trials reported that combining engineered NK cells with mAbs with ADCC activity can result in a superior clinical response compared to mAbs alone. Next generation of clinical trials, employing engineered NK cells with mAbs with higher affinity for CD16 expressed on NK cells, will provide more effective and higher-quality treatments to cancer patients.