Natural and engineered kallikrein inhibitors: an emerging pharmacopoeia (original) (raw)
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Unleashing the therapeutic potential of human kallikrein-related serine proteases
Nature reviews. Drug discovery, 2015
Tissue kallikreins are a family of fifteen secreted serine proteases encoded by the largest protease gene cluster in the human genome. In the past decade, substantial progress has been made in characterizing the natural substrates, endogenous inhibitors and in vivo functions of kallikreins, and studies have delineated important pathophysiological roles for these proteases in a variety of tissues. Thus, kallikreins are now considered attractive targets for the development of novel therapeutics for airway, cardiovascular, tooth, brain, skin and neoplastic diseases. In this Review, we discuss recent advances in our understanding of the physiological functions and pathological implications of kallikrein proteases, and highlight progress in the identification of kallikrein inhibitors, which together are bringing us closer to therapeutically targeting kallikreins in selected disease settings.
Inhibitors of kallikrein‐related peptidases: An overview
Medicinal Research Reviews, 2017
Kallikrein‐related peptidases (KLKs) are a family of 15 secreted serine proteases that are involved in various physiological processes. Their activities are subtly regulated by various endogenous inhibitors, ranging from metallic ions to macromolecular entities such as proteins. Furthermore, dysregulation of KLK activity has been linked to several pathologies, including cancer and skin and inflammatory diseases, explaining the numerous efforts to develop KLK‐specific pharmacological inhibitors as potential therapeutic agents. In this review, we focus on the huge repertoire of KLKs inhibitors reported to date with a special emphasis on the diversity of their molecular mechanisms of inhibition.
Natural and synthetic inhibitors of kallikrein-related peptidases (KLKs)
Biochimie, 2010
Including the true tissue kallikrein KLK1, kallikrein-related peptidases (KLKs) represent a family of fifteen mammalian serine proteases. While the physiological roles of several KLKs have been at least partially elucidated, their activation and regulation remain largely unclear. This obscurity may be related to the fact that a given KLK fulfills many different tasks in diverse fetal and adult tissues, and consequently, the timescale of some of their physiological actions varies significantly. To date, a variety of endogenous inhibitors that target distinct KLKs have been identified. Among them are the attenuating Zn 2þ ions, active site-directed proteinaceous inhibitors, such as serpins and the Kazal-type inhibitors, or the huge, unspecific compartment forming a 2 -macroglobulin. Failure of these inhibitory systems can lead to certain pathophysiological conditions. One of the most prominent examples is the Netherton syndrome, which is caused by dysfunctional domains of the Kazal-type inhibitor LEKTI-1 which fail to appropriately regulate KLKs in the skin. Small synthetic inhibitory compounds and natural polypeptidic exogenous inhibitors have been widely employed to characterize the activity and substrate specificity of KLKs and to further investigate their structures and biophysical properties. Overall, this knowledge leads not only to a better understanding of the physiological tasks of KLKs, but is also a strong fundament for the synthesis of small compound drugs and engineered biomolecules for pharmaceutical approaches. In several types of cancer, KLKs have been found to be overexpressed, which makes them clinically relevant biomarkers for prognosis and monitoring. Thus, down regulation of excessive KLK activity in cancer and in skin diseases by small inhibitor compounds may represent attractive therapeutical approaches.
Chemistry & Biology, 2009
Human kallikrein-related peptidase 4 (hk4/prostase), a trypsin-like serine protease, is a potential target for prostate cancer treatment as a consequence of its proteolytic ability to activate many tumorigenic and metastatic pathways such as the protease activated receptors (PARs). Currently there are no KLK4specific small-molecule inhibitors available for therapeutic development. Here we re-engineer the naturally-occurring sunflower trypsin inhibitor (SFTI) to specifically block the proteolytic activity of KLK4 and prevent stimulation of PAR activity in cell based systems. The re-engineered inhibitor was designed using a combination of molecular modelling and sparse matrix substrate screening. The resulting inhibitor showed highly specific inhibition of KLK4 against the peptide substrate FVQR-para-nitroanilide (K i of 3.25 ± 1.60 nM) and the macromolecular substrate fibrinogen, blocked KLK4 initiated calcium flux from PAR2 and displayed remarkable stability in cell based assays with a half life of four days.
Direct and indirect inhibition of kallikrein family proteases
2019
Kallikreins are enzymes involved in many diseases, including prostate cancer and a variety of skin disorders — blocking their activity can treat these diseases. This thesis examines mechanisms of inhibition within kallikreins, and how an inhibitor molecule from sunflower seeds works, laying the groundwork for future drug development.
Protein & Peptide Letters, 2013
Kallikrein-related peptidases (KLKs) are trypsin-like and chymotrypsin-like serine proteases which are expressed in several tissues. Their activity is tightly controlled by inhibitors including members of the serine protease Kazal-type (SPINK) family. These enzymes are promising targets for the treatment of skin desquamation, inflammation and cancer. Spink3 or caltrin I is expressed in mouse pancreas and males accessory glands and the resulting mature protein has been associated with different activities such as an inhibitor of trypsin and acrosin activity, calcium transport inhibitor in sperm and inhibitor of cell proliferation during embryogenesis. In this study, we produced a soluble recombinant Spink3 from mouse seminal vesicle (rmSpink3) that inhibited the activity of human KLKs. Using FRET substrates, rmSpink3 exhibited a potent inhibitory activity against human KLK2, KLK3, KLK5 (Ki ranging from 260 to 1500 nM), and to a lesser extent against KLK6, KLK1 and KLK7 (Ki around 3000 nM). As shown by mass spectrometry analysis of rmSpink3 incubated with trypsin, the inhibitor was not truncated by the target enzyme. Based on the in silico analysis of the expression of Spink3/SPINK1 and KLKs it is speculated that some KLKs may be natural targets of Spink3/SPINK1, however experimental confirmation using both proteins from mouse or human origin is needed. This work shows that rmSpink3 is a potent inhibitor of various human KLK members suggesting the potential of this molecule in the diagnosis/prevention of several human diseases.
European Journal of Medicinal Chemistry, 2013
Netherton syndrome is caused by loss-of-function mutations in SPINK5 encoding the Kazal-type inhibitor LEKTI-1 leading to dysregulation of proteolytic cascades involving several kallikreins. We used both structure-based and ligand-based virtual screening computations to identify commercially available noncovalent inhibitors of human kallikrein 5 (hK5), a serine protease (trypsin-like) that plays a central role in the initiation of the molecular cascades leading to the Netherton syndrome phenotype. The efficacy and mechanism of inhibition of the identified new families of organic compounds were analyzed not only for hK5 but also on other proteases implicated in the cascades (hK7, hK14 and matriptase). These inhibitors are nontoxic on healthy human keratinocytes and are structurally different from traditional serine protease inhibitors validating their potential utility as initial hits to control proteolytic disorders observed in dermatological pathologies such as Netherton syndrome.
Synthesis of potent and selective inhibitors of human plasma kallikrein
Bioorganic & Medicinal Chemistry Letters, 1999
The synthesis and in vitro enzyme inhibition profile of a series of novel trifluoromethyiketone (TFMK) inhibitors of human plasma kallikrein (PK) are described. We have developed an efficient method for the construction of peptide TFMKs that provides the final product devoid of compromised stereochemieal integrity. Many of these compounds are potent inhibitors of PK and exhibit reduced inhibition of tissue kaUikrein (TK) and plasmin (HP).