Transforming growth factor β (TGF-β) has been shown to promote tumor invasion and metastasis by activating the matrix metalloproteinases (MMPs); however, signaling mechanisms remain controversial and therapies targeting MMPs are still suboptimal. In the present study, we found that combined therapy with Asiatic acid (AA), a Smad7 agonist, and Naringenin (NG), a Smad3 inhibitor, effectively retrieved the balance between Smad3 and Smad7 signaling in the TGF-β-rich tumor microenvironment and thus significantly suppressed tumor invasion and metastasis in mouse models of melanoma and lung carcinoma. Mechanistically, we unraveled that Smad3 acted as a transcriptional activator of MMP2 and as a transcriptional suppressor of tissue inhibitors of metalloproteinase-2 (TIMP2) via binding to 5′ UTR of MMP2 and 3′ UTR of TIMP2, respectively. Treatment with NG inhibited Smad3-mediated MMP2 transcription while increasing TIMP, whereas treatment with AA enhanced Smad7 to suppress TGF-β/Smad3 signaling, as well as the activation of MMP2 by targeting the nuclear factor-κB (NF-κB)-membrane-type-1 MMP (MT1-MMP) axis. Therefore, the combination of AA and NG additively suppressed invasion and metastasis of melanoma and lung carcinoma by targeting TGF-β/Smad-dependent MMP2 transcription, post-translational activation, and function.

转化生长因子β（TGF-β）已显示通过激活基质金属蛋白酶（MMP）促进肿瘤侵袭和转移。然而，信号传导机制仍存在争议，针对MMP的疗法仍不是最佳选择。在本研究中，我们发现与Smad7激动剂Asiatic acid（AA）和Smad3抑制剂Naringenin（NG）联合治疗可在富含TGF-β的肿瘤微环境中有效地恢复Smad3和Smad7信号之间的平衡。因此显着抑制了黑色素瘤和肺癌小鼠模型中的肿瘤侵袭和转移。从机理上讲，我们发现Smad3通过分别与MMP2的5'UTR和TIMP2的3'UTR结合而充当MMP2的转录激活因子和金属蛋白酶2（TIMP2）的组织抑制剂的转录抑制剂。NG处理可抑制Smad3介导的MMP2转录，同时增加TIMP，而AA处理可增强Smad7以抑制TGF-β/ Smad3信号转导，并通过靶向核因子-κB（NF-κB）-膜-激活MMP2。 Type-1 MMP（MT1-MMP）轴。因此，AA和NG的组合可通过靶向TGF-β/ Smad依赖性MMP2转录，翻译后激活和功能来抑制黑素瘤和肺癌的侵袭和转移。