ANT1 suppression inhibits the progression of colorectal cancer by suppressing PINK1/Parkin-mediated mitophagy

Abstract

Mitochondrial dysfunction is closely related to tumor development. Adenine nucleotide translocator 1 (ANT1), which promotes ADP/ATP translocation across the inner mitochondrial membrane, is an important protein involved in mitochondrial function and plays a role in a variety of diseases, including cancers. However, its role in colorectal cancer (CRC) progression remains poorly understood. This study aims to explore the potential role of ANT1 in CRC and its relationship with mitophagy. Through immunohistochemical analysis, we find that ANT1 expression is significantly higher in the tumor tissues of CRC patients than in adjacent normal tissues and that its overexpression is associated with poor prognosis. Further experiments demonstrate that ANT1 knockdown significantly inhibits CRC cell proliferation, migration, and invasion and leads to mitochondrial dysfunction, increased ROS production, and apoptosis by suppressing mitophagy. Mechanistically, ANT1 knockdown downregulates the PINK1/Parkin pathway, thereby inhibiting mitophagy activity. Notably, PINK1 overexpression partially rescues the cellular dysfunction induced by ANT1 knockdown, suggesting a potential role for PINK1 in reversing the suppression of mitophagy. In vivo xenograft models also show that ANT1 knockdown markedly inhibits tumor growth. In conclusion, ANT1 may play a critical role in CRC progression by regulating mitophagy, providing a basis for its potential as a therapeutic target.

1. Introduction

Colorectal cancer (CRC) is the third most common cancer and the third leading cause of cancer-related death [1,2]. Studies estimate that by the year 2040, the burden of CRC is projected to increase to 3.2 million new cases and 1.6 million deaths, with the majority of cases occurring in countries with high or very high human development indices [3–5]. Recent research has shown a steady increase in the incidence of CRC among young individuals [6,7]. Surgery is the treatment of choice in the early stages, but patients with advanced disease have lower survival rates and rely on neoadjuvant chemotherapy and targeted immunotherapies [8,9]. Currently, some progress has been made in the development of targeted drugs for the treatment of CRC, but their therapeutic effects are affected by the location and molecular characteristics of the tumor [10,11]. Therefore, more scientific and effective treatments for CRC are becoming a major challenge in our new era of precision medicine.

Mitochondria, commonly known as the cellular “powerhouse” are critical for maintaining homeostasis and supporting diverse cellular functions while also playing an important role in determining cell fate by participating in programmed cell death [12–14]. Adenine nucleotide translocase (ANT), a dual-function protein located on the inner membrane of mitochondria, regulates adenosine triphosphate (ATP)/adenosine diphosphate (ADP) exchange for metabolism and is part of the mitochondrial permeability transition pore, which regulates cell death [15–19]. The ANT family consists of four subtypes, ANT1, ANT2, ANT3, and ANT4, which are encoded by four nuclear genes whose expression is tightly regulated. ANT1, encoded by the nuclear gene SLC25A4, is a heart- and muscle-specific subtype of the ANT mitochondrial inner membrane protein family [20]. Hoshino et al. [21] reported that ANT1 is essential for mitophagy, as its knockout in mice leads to reduced mitophagy and the accumulation of abnormal mitochondria.

Mitophagy is a critical mitochondrial quality control mechanism that eliminates damaged mitochondria and reduces the production of reactive oxygen species (ROS) [22]. Changes in mitochondrial function play pivotal roles in cancer development, as mitophagy can either support cell survival or promote cell death depending on the cellular environment, functioning as a double-edged sword in tumor cells [23]. On one hand, mitochondria are crucial for energy production in eukaryotic cells, and their maintenance is essential for cell survival [24]. Mitophagy helps alleviate stress by clearing dysfunctional mitochondria [25]. On the other hand, mitophagy suppresses tumor growth by removing defective mitochondria, which might otherwise transform cells and contribute to tumorigenesis [26].