Department of Surgery, The Royal Melbourne Hospital, The University of Melbourne, 5th Floor Clinical Sciences Building, Parkville, VIC 3050, Australia.
Huagene Institute, Kecheng Science and Technology Park, Pukou District, Nanjing 211806, China.
Cells. 2024 Jul 9;13(14):1166. doi: 10.3390/cells13141166.
Metastasis is the main cause of cancer-related deaths, but efficient targeted therapies against metastasis are still missing. Major gaps exist in our understanding of the metastatic cascade, as existing methods cannot combine sensitivity, robustness, and practicality to dissect cancer progression. Addressing this issue requires improved strategies to distinguish early metastatic colonization from metastatic outgrowth.
Luciferase-labelled MDA-MB-231, MCF7, and 4T1 breast cancer cells were spiked into samples from tumour-naïve mice to establish the limit of detection for disseminated tumour cells. Luciferase-labelled breast cancer cells (±unlabelled cancer-associated fibroblasts; CAFs) were orthotopically implanted in immunocompromised mice. An ex vivo luciferase assay was used to quantify tumour cell dissemination.
In vitro luciferase assay confirmed a linear and positive correlation between cancer cell numbers and the bioluminescence detected at single cell level in blood, brain, lung, liver, and mammary fat pad samples. Remarkably, single luciferase-labelled cancer cells were detectable in all of these sites, as the bioluminescence quantified in the analysed samples was substantially higher than background levels. Ex vivo, circulating tumour cells, metastasis, and tumour self-seeding were detected in all samples from animals implanted with highly metastatic luciferase-labelled MDA-MB-231 cells. In turn, detection of poorly metastatic luciferase-labelled MCF7 cells was scarce but significantly enhanced upon co-implantation with CAFs as early as 20 days after the experiment was initiated.
These results demonstrate the feasibility of using an ultrasensitive luciferase-based method to dissect the mechanisms of early metastatic colonization to improving the development of antimetastatic therapies.
转移是癌症相关死亡的主要原因，但针对转移的有效靶向治疗仍有待开发。我们对转移级联的理解存在重大差距，因为现有的方法无法将灵敏度、稳健性和实用性结合起来，以剖析癌症的进展。解决这个问题需要改进策略，以区分早期转移性定植和转移性生长。
荧光素酶标记的 MDA-MB-231、MCF7 和 4T1 乳腺癌细胞被注入肿瘤未受累的小鼠样本中，以确定播散性肿瘤细胞的检测下限。荧光素酶标记的乳腺癌细胞（±未标记的癌相关成纤维细胞；CAFs）被原位植入免疫缺陷小鼠中。使用离体荧光素酶测定法来定量肿瘤细胞的播散。
在体外荧光素酶测定中，我们证实了癌症细胞数量与在血液、大脑、肺、肝和乳腺脂肪垫样本中单细胞水平检测到的生物发光之间存在线性正相关。值得注意的是，在所有这些部位都可以检测到单个荧光素酶标记的癌细胞，因为分析样本中定量的生物发光显著高于背景水平。在体外，从植入高转移性荧光素酶标记 MDA-MB-231 细胞的动物的所有样本中都检测到了循环肿瘤细胞、转移和肿瘤自播种。相反，当与 CAFs 共植入时，检测到低转移性荧光素酶标记 MCF7 细胞的情况很少，但在实验开始后 20 天就显著增强。
这些结果证明了使用超灵敏荧光素酶方法来剖析早期转移性定植的机制以改善抗转移治疗的开发是可行的。
