Ferroptosis is a cell death pathway triggered by an imbalance between the production of oxidants and antioxidants, which plays an emerging role in tumorigenesis. It is mainly regulated at three different levels including iron metabolism, the antioxidant response, and lipid metabolism. Epigenetic dysregulation is a “hallmark” of human cancer, with nearly half of all human cancers harboring mutations in epigenetic regulators such as microRNA. While being the crucial player in controlling gene expression at the mRNA level, microRNAs have recently been shown to modulate cancer growth and development via the ferroptosis pathway. In this scenario, some miRNAs have a function in upregulating, while others play a role in inhibiting ferroptosis activity. The investigation of validated targets using the miRBase, miRTarBase, and miRecords platforms identified 13 genes that appeared enriched for iron metabolism, lipid peroxidation, and antioxidant defense; all are recognized contributors of tumoral suppression or progression phenotypes. This review summarizes and discuss the mechanism by which ferroptosis is initiated through an imbalance in the three pathways, the potential function of microRNAs in the control of this process, and a description of the treatments that have been shown to have an impact on the ferroptosis in cancer along with potential novel effects.

The TP53 tumor suppressor gene is one of the most studied gene in virtue of its ability to prevent cancer development by regulating apoptosis, cell cycle arrest, DNA repair, autophagy and senescence. Furthermore, the modulation of metabolism by P53 is fundamental for tumor suppressor activity. Studies in mouse models showed that mice carrying TP53 mutations affecting the acetylation in the DNA binding domain still retain the ability to transactivate genes involved in metabolism. Noteworthy, mice expressing the triple 3KR or the single K117R mutant do not show early on-set tumor development in contrast to TP53^−/− mice. Interestingly, the mouse K117R mutation corresponds to the human tumor-derived K120R modification, which abrogates P53-dependent activation of apoptosis without affecting growth arrest. In this study, we investigated the property of the human P53 K120R mutant in the regulation of metabolism by analyzing the transcriptional specificity in yeast- and mammalian-based reporter assays, the metabolic phenotype associated to its expression in colon cancer HCT116^TP53−/− cells and the induction of P53 targets and proteins involved in the antioxidant response. These properties were analyzed in comparison to wild type P53 protein, the human triple mutant corresponding to mouse 3KR and the cancer hot-spot R273H mutant. We confirm the selective functionality of P53 K120R mutant, which shows a transcriptional activity on cell cycle arrest but not on apoptotic targets. Interestingly, this mutant shows a partial transactivation activity on p53 response element belonging to the metabolic target TIGAR. Moreover, we observe a significant uncoupling between oxygen consumption and ATP production associated with higher lipid peroxidation level in all P53 mutants carrying cells with respect to wild type P53 expressing cells. Noteworthy, in the absence of a pro-oxidative challenge, cells expressing K120R mutant retain a partial capacity to modulate glucose metabolism, limiting lipid peroxidation with respect to the other P53 mutants carrying cells. Lastly, especially in presence of human 3KR mutant, a high expression of proteins involved in the antioxidant response is found. However, this response does not avoid the increased lipid peroxidation, confirming that only wild type P53 is able to completely counteract the oxidative stress and relative damages.

In Chronic Lymphocytic Leukemia (CLL), mutations at the TP53 tumor suppressor gene are an important hallmark since they may strongly influence the therapeutic decision. PRIMA-1^Met (also known as APR-246/Eprenetapopt) is a small molecule able to restore the wild-type (wt) p53 conformation to mutant p53 proteins and to stimulate apoptosis in tumor cells; in addition, it can deplete the glutathione reservoir, increasing reactive oxygen species (ROS) production. In this study, we investigated whether combining PRIMA-1^Met with Sulfasalazine (SAS), a SLC7A11/xCT inhibitor, reduces CLL cell viability by targeting mutant p53 and the glutathione pathway. The results demonstrated that, in CLL cells, PRIMA-1^Met did not restore the wt functions in the mutant p53 proteins, but it strongly reduced the antioxidant defense and induced cell death. PRIMA-1^Met and SAS combination synergistically reduced cell survival regardless of p53 status and further impaired antioxidant capacity, especially in mutant p53 cells, linking their cytotoxic effect to redox imbalance. Thus, the association of PRIMA-1^Met with drugs targeting the antioxidant response could represent a valid strategy to kill CLL cells carrying either wt or mutant p53.

The TP53 gene encodes the well-known P53 tumor suppressor protein, which plays a crucial role in preventing cancer development. Germline TP53 variants cause Li-Fraumeni Syndrome (LFS), an autosomal dominant disorder associated with early-onset cancers, including breast cancer, brain tumors, leukemias, bone cancers, and soft tissue sarcomas. Functional studies in yeast and human cells demonstrated that TP53 variants can have various effects, such as partial or complete loss of function and even gain of pro-oncogenic activities. Here, we identified a germline TP53 variant c.671A>C, resulting in the missense mutant protein p.E224A in the context of early-onset retroperitoneal rhabdomyosarcoma occurring in a child with a notable family history of cancer, suggestive of LFS. The variant was initially classified as a variant of uncertain significance (VUS). Functional assays in yeast and human cells demonstrated wild type-like activity of the protein p.E224A; however, in silico analysis predicted at RNA level a splicing defect, which we further investigated using a minigene approach. This analysis showed that the variant c.671A>C causes the skipping of exon 6, potentially introducing a frameshift in cDNA and a premature stop codon, which likely triggers nonsense-mediated mRNA decay; the loss of heterozygosity at the c.671 position in the parent’s TP53 transcript further confirmed the splicing impairment. In summary, these findings supported reclassifying the TP53 germline variant c.671A>C (p.E224A) from VUS to likely pathogenic, providing a definitive molecular diagnosis for family counseling. Additionally, this study sheds light on how certain TP53 variants that are defined as missense, can be linked to disease mechanisms through RNA splicing disruption, highlighting the need for their deep functional assessment.