Introduction
(Laura)
-Alectinib is an inhibitor of oncogenic c-ros oncogene1 (ROS1) fusion kinases as well as anaplastic lymphoma kinase (ALK). (insert green scene of protein bound to ligand, linking on the word Inhibitor)
-It is a second generation drug that differs from the kinase inhibitor drugs preceding it, in that it's aim is to fight resistance to the inhibitor drugs that occur through mutations (key features/what makes it different)
-This inhibiting complex is likely to be effective in non-small cell lung cancer and other ROS1 fusion-positive cancers
- It is an ATP-competitve inhibitor
-Having difficulties inserting new scene
Overall Structure
b. Overall structure (Katie)
Describe the overall structure of your protein in words and make "green scenes" to illustrate your points.
What elements of secondary structure are present (ie 5 alpha helices and 2 beta strands) and how are they organized?
-The Human ROS1 Kinase Domain in Complex consists of a small N-terminus lob and a large C-terminus lobe. The N-terminus lobe contains a 5 stranded antiparallel bets sheet and an alpha helix.
-The C-terminus lobe consists mainly of an alpha helix which contains 6 segments, as well as 2 conserved beta strands. This lobe has a helical structure and is where the regulatory activation loop is located.
Additional description and green scenes could illustrate the polar/nonpolar distrubution of amino acids (is the inside of the barrel polar or nonpolar?), packing of amphipathic elements, etc.
Ligand 5p8: (10r)-7-amino-12-fluoro-2,10,16-trimethyl-15-oxo-10,15,16,17-tetrahydro-2h-8,4-(metheno)pyrazolo[4,3-h][2,5,11]benzoxadiazacyclotetradecine-3-carbonitrile
289 amino acids
Binding Interactions
c. The binding interaction of PF-0643922 with ROS1/ALK is what makes Alectinib a second generation drug. Patients developed resistance to the first generation drug crizotinib by developing point mutations in the ROS1 kinase. PF-0643922 is a very strong potent and selective small molecule inhibitor that targets the (ROS1) fusion kinase. Inhibition of the fusion kinase is the goal of this cancer therapy. PF-0643922 is the most potent and selective ROS1 inhibitor discovered to date according to the paper cited. PF-0643922 is the small molecule of the protein complex of ROS1 inhibitors that gets the job done on its own compared to alectinib and crizotinib. Alectinib's goal is to fight resistance to the inhibition of ROS1 kinase through selectively binding to the point mutations. However PF-0643922 has been shown to inhibit the crizotinib-refractory ROS1(G2032R) mutation and the ROS1(G2026M) gatekeeper mutation which would ultimately make crizotinib and alectinib obsolete ROS1 inhibitors. The crystal structure between the PF-0643922-ROS1 complex shows the interactions that contribute to the high affinity binding of PF-0643922. The first blue dot alone by itself is the N terminus, and the three carbon atoms next to the nitrogen and oxygen is the C terminus. The binding site of the protein complex is therefor the cluster of atoms with the green dot.
Additional Features
d. Additional features
Describe and use green scenes to illustrate additional features of the macromolecule. What you do here depends on what information is available. If a structure of the protein-substrate complex is available, you could compare protein interactions with the substrate vs. with the drug. If the drug is a transition state inhibitor, explain and illustrate that (eg include a reaction scheme with structures of the substrate, transition state and product -- but don't borrow a published scheme).
- PF-06463922 is a novel compound with high affinity for ROS1 and ALK kinases
- PF-06463922 Inhibits Crizotinib-Resistant Mutant ROS1
- PF-06463922 effectively inhibits the catalytic activity of recombinant ROS1
- Compared with other kinase inhibitors, PF-06463922 was >10-fold more potent than crizotinib and foretinib and >100-fold more potent than either ceritinib or alectinib in both ROS1 fusion-mediated cell growth and ROS1 kinase inhibition
- To date, interchromosomal translocations or intrachromosomal deletions have resulted in the production of 20 different N-terminal ROS1 fusion genes in a variety of cancers
- ROS1 is a distinct receptor with a kinase domain that is phylogenetically related to the anaplastic lymphoma kinase/lymphocyte-specific protein tyrosine kinase (ALK/LTK) and insulin receptor (INSR) RTK families (20), suggesting that tyrosine kinase inhibitors for these receptors could have cross-activity against ROS1
Quiz Question 1
e. Quiz question
Pose an interesting, quiz-worthy question that involves thinking and investigating the molecule with the green scenes that you provide here. Submit the answer to your question in Moodle and do not share it with other students. Best questions will be chosen for a Moodle quiz, so that students can explore your structure and green scenes to figure out the answer to your quiz question.
See Also
[Structure of Human ROS1 Kinase Domain in Complex]
[Tyrosine kinase]
Credits
Introduction - Laura Feeley
Overall Structure - Katie Kwan
Drug Binding Site - Luke Ruksnaitis
Additional Features - Rafiyu Ishtiaq
Quiz Question 1 - Daniel Peters
References
Zou, Helen Y. et al. “PF-06463922 Is a Potent and Selective next-Generation ROS1/ALK Inhibitor Capable of Blocking Crizotinib-Resistant ROS1 Mutations.” Proceedings of the National Academy of Sciences of the United States of America 112.11 (2015): 3493–3498. PMC. Web. 9 Apr. 2016.
[2]
- ↑ Zou HY, Li Q, Engstrom LD, West M, Appleman V, Wong KA, McTigue M, Deng YL, Liu W, Brooun A, Timofeevski S, McDonnell SR, Jiang P, Falk MD, Lappin PB, Affolter T, Nichols T, Hu W, Lam J, Johnson TW, Smeal T, Charest A, Fantin VR. PF-06463922 is a potent and selective next-generation ROS1/ALK inhibitor capable of blocking crizotinib-resistant ROS1 mutations. Proc Natl Acad Sci U S A. 2015 Mar 2. pii: 201420785. PMID:25733882 doi:http://dx.doi.org/10.1073/pnas.1420785112
- ↑ McKeage K. Alectinib: a review of its use in advanced ALK-rearranged non-small cell lung cancer. Drugs. 2015 Jan;75(1):75-82. doi: 10.1007/s40265-014-0329-y. PMID:25428710 doi:http://dx.doi.org/10.1007/s40265-014-0329-y
