Division of Reproductive Sciences, Department of Obstetrics and Gynecology, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado.
Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado.
Cancer Res Commun. 2024 Jul 1;4(7):1625-1642. doi: 10.1158/2767-9764.CRC-24-0240.
Genome instability is a hallmark of cancer crucial for tumor heterogeneity and is often a result of defects in cell division and DNA damage repair. Tumors tolerate genomic instability, but the accumulation of genetic aberrations is regulated to avoid catastrophic chromosomal alterations and cell death. In ovarian cancer tumors, claudin-4 is frequently upregulated and closely associated with genome instability and worse patient outcomes. However, its biological association with regulating genomic instability is poorly understood. Here, we used CRISPR interference and a claudin mimic peptide to modulate the claudin-4 expression and its function in vitro and in vivo. We found that claudin-4 promotes a tolerance mechanism for genomic instability through micronuclei generation in tumor cells. Disruption of claudin-4 increased autophagy and was associated with the engulfment of cytoplasm-localized DNA. Mechanistically, we observed that claudin-4 establishes a biological axis with the amino acid transporters SLC1A5 and LAT1, which regulate autophagy upstream of mTOR. Furthermore, the claudin-4/SLC1A5/LAT1 axis was linked to the transport of amino acids across the plasma membrane as one of the potential cellular processes that significantly decreased survival in ovarian cancer patients. Together, our results show that the upregulation of claudin-4 contributes to increasing the threshold of tolerance for genomic instability in ovarian tumor cells by limiting its accumulation through autophagy.
Autophagy regulation via claudin-4/SLC1A5/LAT1 has the potential to be a targetable mechanism to interfere with genomic instability in ovarian tumor cells.
基因组不稳定性是癌症的一个重要特征，对肿瘤异质性至关重要，通常是细胞分裂和 DNA 损伤修复缺陷的结果。肿瘤耐受基因组不稳定性，但遗传异常的积累受到调控，以避免灾难性的染色体改变和细胞死亡。在卵巢癌肿瘤中，紧密连接蛋白-4 经常上调，与基因组不稳定性和患者预后不良密切相关。然而，其与调节基因组不稳定性的生物学关联知之甚少。在这里，我们使用 CRISPR 干扰和紧密连接蛋白模拟肽来调节体外和体内的紧密连接蛋白-4 表达及其功能。我们发现，紧密连接蛋白-4 通过肿瘤细胞中微核的产生促进了基因组不稳定性的耐受机制。破坏紧密连接蛋白-4 会增加自噬，并与细胞质定位 DNA 的吞噬有关。从机制上讲，我们观察到紧密连接蛋白-4 与氨基酸转运蛋白 SLC1A5 和 LAT1 建立了一个生物学轴，该轴在上游调节 mTOR 的自噬。此外，紧密连接蛋白-4/SLC1A5/LAT1 轴与氨基酸穿过质膜的运输有关，这是导致卵巢癌患者生存率显著降低的潜在细胞过程之一。总之，我们的研究结果表明，紧密连接蛋白-4 的上调通过自噬限制其积累，有助于增加卵巢肿瘤细胞对基因组不稳定性的耐受阈值。
通过紧密连接蛋白-4/SLC1A5/LAT1 调节自噬有可能成为干预卵巢肿瘤细胞基因组不稳定性的靶向机制。
