Department of Biochemistry and Molecular Biology, College of Medicine, University of South Alabama, Mobile, AL, 36688, United States.
Department of Biochemistry and Molecular Biology, College of Medicine, University of South Alabama, Mobile, AL, 36688, United States; Department of Biotechnology, Korea National University of Transportation, Chungbuk, 27909, Republic of Korea.
Biochem Biophys Res Commun. 2019 Feb 19;509(4):1034-1040. doi: 10.1016/j.bbrc.2019.01.050. Epub 2019 Jan 17.
Malignant melanoma typically metastasizes to lymph nodes (LNs) as a primary or in-transit lesion before secondary metastasis occurs, and LN biopsy is a common procedure to diagnose melanoma progression. Since cancer metastasis is a complex process where various interactions between tumor cells and the stroma play key roles in establishing metastatic lesions, the exact mechanisms underlying melanoma metastasis to LNs remains unknown. It has been known that focal adhesion kinase (FAK) activity promotes the expression of proinflammatory vascular cell adhesion molecule-1 (VCAM-1). As VCAM-1 is a major receptor for α4 integrin and plays a key role in leukocyte recruitment, we reasoned that inhibition of FAK activity may reduce VCAM-1 expression within LNs and thus reduce metastasis of α4 integrin-expressing melanoma to LNs. First, we found that a pharmacological FAK inhibitor, PF-271, blocked tumor necrosis factor-α (TNF-α)-mediated VCAM-1 expression on human dermal lymphatic endothelial cells (HDLECs). In vitro, PF-271 significantly decreased B16F10 melanoma adhesion to and transmigration through HDLECs compared to TNF-α treated cells. Furthermore, in vivo FAK inhibition by oral PF-271 administration reduced VCAM-1 expression in inguinal, cervical, and popliteal LNs compared to vehicle treated mice. Finally, in a footpad metastasis model, B16F10 melanoma cells were injected into the right footpad of C57BL/6 mice, and PF-271 (50 mg/kg, twice daily for 6 days) was orally administrated after 1 week of tumor transplantation. While untreated mice exhibited significant metastatic melanoma lesions in popliteal LNs, PF-271 treated mice showed only marginal melanoma metastasis. These results support the possibility that FAK inhibitors may be a novel preventative option in melanoma metastasis by blocking VCAM-1 expression in LNs.
恶性黑色素瘤通常在发生继发性转移之前，以原发性或转移前病变的形式转移到淋巴结 (LNs)，而淋巴结活检是诊断黑色素瘤进展的常见程序。由于癌症转移是一个复杂的过程，其中肿瘤细胞与基质之间的各种相互作用在建立转移性病变中起着关键作用，因此黑色素瘤转移到 LNs 的确切机制尚不清楚。已知粘着斑激酶 (FAK) 活性促进促炎血管细胞粘附分子-1 (VCAM-1) 的表达。由于 VCAM-1 是α4 整合素的主要受体，在白细胞募集中起着关键作用，我们推断抑制 FAK 活性可能会降低 LNs 中 VCAM-1 的表达，从而减少表达α4 整合素的黑色素瘤向 LNs 的转移。首先，我们发现一种药理 FAK 抑制剂 PF-271 阻断了肿瘤坏死因子-α (TNF-α) 介导的人真皮淋巴管内皮细胞 (HDLECs) 中 VCAM-1 的表达。在体外，与 TNF-α 处理的细胞相比，PF-271 显著降低了 B16F10 黑色素瘤对 HDLECs 的粘附和迁移。此外，与载体处理的小鼠相比，口服 PF-271 给药通过 FAK 抑制减少了腹股沟、颈和腘淋巴结中 VCAM-1 的表达。最后，在足底转移模型中，将 B16F10 黑色素瘤细胞注射到 C57BL/6 小鼠的右足底，在肿瘤移植后 1 周开始每天两次口服 PF-271（50mg/kg，连续 6 天）。未治疗的小鼠在腘淋巴结中表现出明显的转移性黑色素瘤病变，而 PF-271 治疗的小鼠仅表现出轻微的黑色素瘤转移。这些结果支持这样一种可能性，即通过阻断 LNs 中 VCAM-1 的表达，FAK 抑制剂可能成为预防黑色素瘤转移的一种新选择。
