Purpose: This study was designed to identify mitochondrial (mt) DNA variations in primary and metastatic uveal melanoma (UM) cell lines and their relation with cell metabolism to gain insight into metastatic progression.

Method: The entire mtDNA genomes were sequenced using Sanger sequencing from two primary UM cell lines (92.1 and MEL270) and two cell lines (OMM2.3 and OMM2.5) derived from liver metastases of the MEL270 patient. The mtDNA copy numbers determined by the ratio of nDNA versus mtDNA. qRT-PCR was used to evaluate expression levels of mitochondrial biogenesis genes.

Results: Sequencing showed that cell line MEL270 and metastases-derived OMM2.3 and OMM2.5 cell lines had homoplasmic single nucleotide polymorphisms (SNPs) representing J1c7a haplogroup, whereas 92.1 cells had mtDNA H31a haplogroup. mtDNA copy numbers were significantly higher in primary cell lines. The metastatic UM cells showed down-regulation of POLG, TFAM, NRF-1 and SIRT1 compared to their primary MEL270 cells. PGC-1α was downregulated in 92.1 and upregulated in MEL270, OMM2.3 and OMM2.5.

Conclusions: Our finding suggests that within metastatic cells, the heteroplasmic SNPs, copy numbers and mitochondrial biogenesis genes are modulated differentially compared to their primary UM cells. Therefore, investigating pathogenic mtDNA variants associated with cancer metabolic susceptibility may provide future therapeutic strategies in metastatic UM.

目的：本研究旨在鉴定原发性和转移性葡萄膜黑色素瘤 (UM) 细胞系中的线粒体 (mt) DNA 变异及其与细胞代谢的关系，以深入了解转移进展。

方法：使用 Sanger 测序法对来自两个原代 UM 细胞系（92.1和MEL270）和源自MEL270患者肝转移瘤的两个细胞系（OMM2.3和OMM2.5）的整个 mtDNA 基因组进行测序。mtDNA 拷贝数由 nDNA 与 mtDNA 的比率决定。qRT-PCR 用于评估线粒体生物发生基因的表达水平。

结果：测序显示细胞系MEL270和转移瘤衍生的OMM2.3和OMM2.5细胞系具有代表 J1c7a 单倍群的同质单核苷酸多态性 (SNP)，而92.1细胞具有 mtDNA H31a 单倍群。mtDNA 拷贝数在原代细胞系中显着更高。与原代 MEL270细胞相比，转移性 UM 细胞显示出POLG、TFAM、NRF-1和SIRT1 的下调。PGC-1α在92.1中下调，在MEL270、OMM2.3和OMM2.5 中上调。

结论：我们的发现表明，在转移细胞内，异质 SNP、拷贝数和线粒体生物发生基因与其原代 UM 细胞相比受到不同的调节。因此，研究与癌症代谢易感性相关的致病性 mtDNA 变异可能为转移性 UM 提供未来的治疗策略。