The mitochondrion is a dynamic eukaryotic organelle that controls lethal and vital functions of the cell. Being a critical center of metabolic activities and involved in many diseases, mitochondria have been attracting attention as a potential target for therapeutics, especially for cancer treatment. Structural and functional differences between healthy and cancerous mitochondria, such as membrane potential, respiratory rate, energy production pathway, and gene mutations, could be employed for the design of selective targeting systems for cancer mitochondria. A number of mitochondria-targeting compounds, including mitochondria-directed conventional drugs, mitochondrial proteins/metabolism-inhibiting agents, and mitochondria-targeted photosensitizers, have been discussed. Recently, certain drug-free approaches have been introduced as an alternative to induce selective cancer mitochondria dysfunction, such as intramitochondrial aggregation, self-assembly, and biomineralization. In this review, we discuss the recent progress in mitochondria-targeted cancer therapy from the conventional approach of drug/cytotoxic agent conjugates to advanced drug-free approaches.

Although pancreatic cancer presents with one of the most unfavorable prognoses, its treatment options are very limited. Mitochondria-targeting moieties, considered a new and prominent treatment modality, are expected to demonstrate synergistic anticancer effects due to their distinct mechanism compared to conventional chemotherapeutic approaches. This study evaluated the therapeutic potential of mitochondria-accumulating self-assembly peptides, referred to as Mito-FFs, utilizing both in vitro and in vivo pancreatic cancer models. Cellular viability assays revealed a concentration-dependent decrease in the survival of MIA-PACA2 pancreatic cancer cells upon exposure to Mito-FF treatment (p < 0.05). Subsequent in vitro Mito-FF treatments prompted the use of several molecular analyses, including Real-time PCR, Western blot analysis, and MitoSOX staining, which collectively indicated an upsurge in apoptosis, a concurrent reduction in the antioxidant enzyme expression, and an elevation in mitochondrial ROS levels (p < 0.05). In a murine xenograft model of pancreatic cancer, the intravenous administration of Mito-FF yielded a notable reduction in the tumor volume. Moreover, it upregulated the expression of pro-apoptotic markers, such as cleaved PARP and c-caspase 3, while concurrently downregulating the expression of an anti-apoptotic marker, MCL-1, as evidenced by both Western blot analysis and immunohistochemical staining (p < 0.05). It also resulted in the reduced expression of antioxidant enzymes like HO-1, catalase, and SOD2 within excised tumor tissues, as confirmed using Western blot analysis (p < 0.05). Cumulatively, the findings underscore the significant anticancer efficacy of Mito-FF against pancreatic cancer cells, predominantly mediated through the induction of apoptosis, suppression of antioxidant enzyme expression, and enhancement of mitochondrial ROS levels within the tumor microenvironment.