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The use of bacteria as an alternative cancer therapy has been reinvestigated in recent years. SL7207: an auxotrophic Salmonella enterica serovar Typhimurium aroA mutant with immune‐stimulatory potential has proven a promising strain for this purpose. Here, we show that systemic administration of SL7207 induces melanoma tumor growth arrest in vivo, with greater survival of the SL7207‐treated group compared to control PBS‐treated mice. Administration of SL7207 is accompanied by a change in the immune phenotype of the tumor‐infiltrating cells toward pro‐inflammatory, with expression of the TH1 cytokines IFN‐γ, TNF‐α, and IL‐12 significantly increased. Interestingly, Ly6C+MHCII+ monocytes were recruited to the tumors following SL7207 treatment and were pro‐inflammatory. Accordingly, the abrogation of these infiltrating monocytes using clodronate liposomes prevented SL7207‐induced tumor growth inhibition. These data demonstrate a previously unappreciated role for infiltrating inflammatory monocytes underlying bacterial‐mediated tumor growth inhibition. This information highlights a possible novel role for monocytes in controlling tumor growth, contributing to our understanding of the immune responses required for successful immunotherapy of cancer. [ABSTRACT FROM AUTHOR]

Immunogenic cell death (ICD) is a type of cancer cell death triggered by certain chemotherapeutic drugs, oncolytic viruses, physicochemical therapies, photodynamic therapy, and radiotherapy. It involves the activation of the immune system against cancer in immunocompetent hosts. ICD comprises the release of damage‐associated molecular patterns (DAMPs) from dying tumor cells that result in the activation of tumor‐specific immune responses, thus eliciting long‐term efficacy of anticancer drugs by combining direct cancer cell killing and antitumor immunity. Remarkably, subcutaneous injection of dying tumor cells undergoing ICD has been shown to provoke anticancer vaccine effects in vivo. DAMPs include the cell surface exposure of calreticulin (CRT) and heat‐shock proteins (HSP70 and HSP90), extracellular release of adenosine triphosphate (ATP), high‐mobility group box‐1 (HMGB1), type I IFNs and members of the IL‐1 cytokine family. In this review, we discuss the cell death modalities connected to ICD, the DAMPs exposed during ICD, and the mechanism by which they activate the immune system. Finally, we discuss the therapeutic potential and challenges of harnessing ICD in cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Mitochondria have traditionally been viewed as the powerhouse of the cell, where they serve, amongst other functions, as a major source of ATP generation. More recently, mitochondria have also been shown to have active roles in a variety of other processes, including apoptotic cell death and inflammation. Here we review the various ways in which mitochondrial functions affect cancer. Although there are many diverse types of cancer, hallmarks have been defined that are applicable to most cancer types. We provide an overview of how mitochondrial functions affect some of these hallmarks, which include evasion of cell death, de-regulated bioenergetics, genome instability, tumour-promoting inflammation and metastasis. In addition to discussing the underlying mitochondrial roles in each of these processes, we also highlight the considerable potential of targeting mitochondrial functions to improve cancer treatment. [ABSTRACT FROM AUTHOR]