Matrix metalloproteinases (MMPs) are zinc dependent proteolytic metalloenzyme. MMP-9 is structurally the largest and one of the most complex forms of matrix metalloproteinases. MMP-9 has the ability to degrade the extracellular matrix (ECM) components and has important role in the pathophysiological functions. Overexpression and dysregulation of MMP-9 is associated with various diseases. Thus, regulation and inhibition of MMP-9 is an important therapeutic approach for combating various diseases including cancer. Inhibitors of MMP-9 can be used as anticancer agents. Till date no selective MMP-9 inhibitors passed the clinical trials. In this review the structure, activation, function and inhibitors of MMP-9 are mainly focused. Some highly active and/or selective MMP-9 inhibitors have been discussed which may be helpful to explore the structural significance of MMP-9 inhibitors. This study may be useful to design new potent and selective MMP-9 inhibitors against cancer in future.

基质金属蛋白酶（MMP）是锌依赖性蛋白水解金属酶。MMP-9在结构上是基质金属蛋白酶的最大形式，也是最复杂的形式之一。MMP-9具有降解细胞外基质（ECM）成分的能力，并且在病理生理功能中具有重要作用。MMP-9的过度表达和失调与多种疾病有关。因此，调节和抑制MMP-9是抗击包括癌症在内的各种疾病的重要治疗方法。MMP-9的抑制剂可用作抗癌药。迄今为止，没有选择性的MMP-9抑制剂通过临床试验。在这篇综述中，MMP-9的结构，激活，功能和抑制剂主要集中在此。已经讨论了一些高活性和/或选择性的MMP-9抑制剂，这可能有助于探索MMP-9抑制剂的结构意义。这项研究可能对将来设计新型有效的选择性MMP-9癌症抑制剂很有用。