Harnessing Listeria monocytogenes: A Promising Approach to Cancer Treatment

The escalating mortality and morbidity rates have prompted global attention to focus on cancer, with the exploration of new treatment options being a key priority. The utilisation of immunotherapy for recurrent or metastatic cancer has emerged as a promising option over the years, despite its limitations in comparison to traditional treatment options. Among the various immunotherapeutic approaches, bacterial-based vectors such as Listeria monocytogenes (Lm) have attracted considerable attention on account of their distinctive characteristics. The utilisation of these vectors entails the exploitation of their capacity to invade antigen-presenting cells (APCs), proliferate intracellularly within immune cells, and disseminate within these cells, thereby augmenting their efficacy in modulating immune responses. It is important to note that the use of bacterial vectors significantly minimises the risks associated with off-target effects. The antitumor effects of Lm can be observed through the reduction of immunosuppressive cells in the tumor microenvironment as well as the stimulation of T cells. Research has indicated that a range of tumour cell types can be targeted by modified Lm vaccines. However, it is acknowledged that Lm vaccines alone may not be sufficient for a comprehensive cancer treatment. Consequently, the employment of Lm vaccines in conjunction with other therapeutic modalities, such as radiotherapy, reactivated adoptive cell therapy, and immune checkpoint inhibitors, has the potential to yield superior outcomes. Consequently, the present review aims to elaborate on recent advancements in the understanding of the antitumor properties of Lm vaccines. The objective of this review is to provide insights into optimising the therapeutic potential of Lm vaccines by comprehensively examining their interplay with the immune system. In order to harness the full therapeutic potential of Lm vaccines in the fight against cancer, researchers and clinicians must gain a deeper understanding of the mechanisms involved.