肿瘤来源的外泌体 ADAM17 通过增强结直肠癌血管通透性促进前转移龛形成。

BACKGROUND: Hematological metastasis has been recognized as a crucial factor contributing to the high rates of metastasis and mortality observed in colorectal cancer (CRC). Notably, exosomes derived from cancer cells participate in the formation of CRC pre-metastatic niches; however, the mechanisms underlying their effects are largely unknown. While our preliminary research revealed the role of exosome-derived disintegrin and metalloproteinase 17 (ADAM17) in the early stages of CRC metastasis, the role of exosomal ADAM17 in CRC hematogenous metastasis remains unclear. METHODS: In the present study, we isolated and purified exosomes using ultracentrifugation and identified exosomal proteins through quantitative mass spectrometry. In vitro, co-culture assays were conducted to evaluate the impact of exosomal ADAM17 on the permeability of the blood vessel endothelium. Vascular endothelial cell resistance, the cell index, membrane protein separation, flow cytometry, and immunofluorescence were employed to investigate the mechanisms underlying exosomal ADAM17-induced vascular permeability. Additionally, a mouse model was established to elucidate the role of exosomal ADAM17 in the modulation of blood vessel permeability and pre-metastatic niche formation in vivo. RESULTS: Our clinical data indicated that ADAM17 derived from the circulating exosomes of patients with CRC could serve as a blood-based biomarker for predicting metastasis. The CRC-derived exosomal ADAM17 targeted vascular endothelial cells, thus enhancing vascular permeability by influencing vascular endothelial cadherin cell membrane localization. Moreover, exosomal ADAM17 mediated the formation of a pre-metastatic niche in nude mice by inducing vascular leakage, thereby promoting CRC metastasis. Nonetheless, ADAM17 selective inhibitors effectively reduced CRC metastasis in vivo. CONCLUSIONS: Our results suggest that exosomal ADAM17 plays a pivotal role in the hematogenous metastasis of CRC. Thus, this protein may serve as a valuable blood-based biomarker and potential drug target for CRC metastasis intervention.

背景：血液转移已被认为是导致结直肠癌（CRC）转移率和死亡率高的关键因素。值得注意的是，癌细胞来源的外泌体参与了结直肠癌前转移灶的形成；然而，其作用机制在很大程度上尚不清楚。虽然我们的初步研究揭示了外泌体衍生的解整合素金属蛋白酶 17（ADAM17）在 CRC 转移早期阶段的作用，但外泌体 ADAM17 在 CRC 血源性转移中的作用尚不清楚。

方法：在本研究中，我们通过超速离心法分离和纯化外泌体，并通过定量质谱法鉴定外泌体蛋白。在体外，通过共培养实验评估外泌体 ADAM17 对血管内皮通透性的影响。采用血管内皮细胞电阻抗、细胞指数、膜蛋白分离、流式细胞术和免疫荧光法研究外泌体 ADAM17 诱导血管通透性的机制。此外，建立了小鼠模型以阐明外泌体 ADAM17 在体内调节血管通透性和前转移灶形成中的作用。

结果：我们的临床数据表明，CRC 患者循环外泌体中的 ADAM17 可作为预测转移的基于血液的生物标志物。CRC 来源的外泌体 ADAM17 靶向血管内皮细胞，通过影响血管内皮钙黏蛋白细胞膜定位从而增强血管通透性。此外，外泌体 ADAM17 通过诱导血管渗漏在裸鼠中介导前转移灶的形成，从而促进 CRC 转移。然而，ADAM17 选择性抑制剂可有效减少 CRC 的体内转移。

结论：我们的研究结果表明，外泌体 ADAM17 在 CRC 的血源性转移中发挥关键作用。因此，该蛋白可能成为 CRC 转移干预的有价值的基于血液的生物标志物和潜在药物靶点。