An OMA1 redox site controls mitochondrial homeostasis, sarcoma growth, and immunogenicity

Mitochondrial metallopeptidase OMA1 in cancer

Our understanding of the roles that mitochondria play in cellular physiology has evolved drastically-from a mere cellular energy supplier to a crucial regulator of metabolic and signaling processes, particularly in the context of development and progression of human diseases such as cancers. The present review examines the role of OMA1, a conserved, redox-sensitive metallopeptidase in cancer biology. OMA1's involvement in mitochondrial quality control, redox activity, and stress responses underscores its potential as a novel target in cancer diagnosis and treatment. However, our incomplete understanding of OMA1's regulation and structural detail presents ongoing challenges to target OMA1 for therapeutic purposes. Further exploration of OMA1 holds promise in uncovering novel insights into cancer mechanisms and therapeutic strategies. In this chapter, we briefly summarize our current knowledge about OMA1, its redox-regulation, and emerging role in certain cancers.

The coenzyme A precursor pantethine enhances antitumor immunity in sarcoma

The tumor microenvironment is a dynamic network of stromal, cancer, and immune cells that interact and compete for resources. We have previously identified the Vanin1 pathway as a tumor suppressor of sarcoma development via vitamin B5 and coenzyme A regeneration. Using an aggressive sarcoma cell line that lacks Vnn1 expression, we showed that the administration of pantethine, a vitamin B5 precursor, attenuates tumor growth in immunocompetent but not nude mice. Pantethine boosts antitumor immunity, including the polarization of myeloid and dendritic cells towards enhanced IFNγ-driven antigen presentation pathways and improved the development of hypermetabolic effector CD8+ T cells endowed with potential antitumor activity. At later stages of treatment, the effect of pantethine was limited by the development of immune cell exhaustion. Nevertheless, its activity was comparable with that of anti-PD1 treatment in sensitive tumors. In humans, VNN1 expression correlates with improved survival and immune cell infiltration in soft-tissue sarcomas, but not in osteosarcomas. Pantethine could be a potential therapeutic immunoadjuvant for the development of antitumor immunity.

OMA1 and YME1L as a Diagnostic Panel in Hepatocellular Carcinoma

Identifying new hepatocellular carcinoma (HCC)-driven signaling molecules and discovering their molecular mechanisms are crucial for efficient and better outcomes. Recently, OMA1 and YME1L, the inner mitochondrial proteases, were displayed to be associated with tumor progression in various cancers; however, their role in HCC has not yet been studied. Therefore, we evaluated the possible role of OMA1/YME1L in HCC staging and discussed their potential role in cellular apoptosis and proliferation. Our study was performed using four groups of male albino rats: a normal control and three diethyl nitrosamine-treated groups for 8, 16, and 24 weeks. The OMA1 and YME1L, matrix-metalloproteinase-9 (MMP-9), and cyclin D1 content were measured in liver tissues, while alpha-fetoprotein (AFP) level was assessed in serum. Additionally, Ki-67 expression was evaluated by immunohistochemistry. The relative hepatic expression of Bax, and tissue inhibitor matrix metalloproteinase (TIMP-3) was measured. Herein, we confirmed for the first time that OMA1 is down-regulated while YME1L is up-regulated in HCC in the three studied stages with subsequent inhibition of apoptosis and cell cycle progression. Furthermore, these proteases have a possible role in metastasis. These newly recognized results suggested OMA1 and YME1L as possible diagnostic tools and therapeutic targets for HCC management.