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Ph.D. (UCLA), 1997; Post-doc (Harvard University); FRACI
Associate Professor; Undergraduate Research Director
Phone: +61 2 9385 4712
Room 219, Dalton Building
UNSW, Kensington, 2052
Research Group Website
1987-1991 B.S. University of Illinois Champaign/Urbana. Research with Prof. Eric N. Jacobsen; 1991-1993 Research Associate Merck Pharmaceuticals; 1993-1997 Ph.D. UCLA Organic chemistry; 1997-2000 Post-doc at Harvard University with Professor Stuart Schreiber; 2000-2006 Assistant Professor at San Diego State University; 2006-2010 Associate Professor at San Diego State University; 2010-2011 Professor at San Diego State University; 2011-current Associate Professor at UNSW.
We vary in size between 10-15 people, including 8-10 post-graduate students, 1-2 honours students, and several undergraduates. Our creative and supportive environment brings out the best in students, and my students typically perform well on their final thesis. Not only do our students produce 5-10 papers throughout their post-graduate career, former members get jobs in both industry and academia. Given our interdisplinary group, each member learns about biological and synthetic aspects of their project. Students have the option to do both chemistry and biology using a combination of skills in both fields in order to complete the entire project. Having trained in the United States, I have significant contacts with other academics and industrial positions and can place my students in desirable jobs throughout Australia and the U.S.
In 2011 I moved my research lab from San Diego State University (SDSU) to the University of New South Wales (UNSW). Our lab currently consists of 16 people (8 Ph.D.s, 3 honours students, and 5 undergraduates). We work on a diverse array of projects involving organic synthesis, molecular and cancer biology, and biochemistry. Our synthesis projects start from a natural product template, and our goal is to design analogues of the natural product. We then test these molecules in cell growth assays, biochemical assays, and cell-based assays in order to determine their activity and potency. Once we understand their biological target, we then design new analogues to improve their selectivity, solubility and efficiency.
Left to Right
Back Row: Michelle, Adrian, Jeanette, Laura, Yuqi, Rashid, Dan, Shelli
Front Row: Jess, Yao, Koay, Sheena, Jane, Vanessa, Nicole, Amirul, Mike
(a) Synthesis and mechanism studies of new heat shock protein inhibitors
Heat shock proteins are in charge of folding and maintaining over 400 other proteins in the cell. They are essential for protecting these proteins from stress-related damage. In cancer cells these proteins are up-regulated and they protect the cells from dying. Blocking the function of heat shock proteins can induce cell death. The clinic drugs (termed "classical inhibitors") bind to Hsp90 at the N-terminus and block ATP from binding to hsp90,thereby inhibiting protein folding. Our data show that these clinic/classical drugs are not only highly promiscious, but they also produce a massive rescue response in the cell called the heat shock response. Thus, their ability to kill cells is limited and has lead to clinical failures, where initially 15 drugs targeted the ATP binding site of Hsp90, and only 3 are left in the clinic. In contrast, our SMX inhibitors not only block the function of heat shock protein 90 (hsp90) but they also shut down the resistance mechanism, the heat shock response. By binding to hsp90 and controlling its C-terminus, the SMX molecules halt protein folding by blocking binding betwee HOP and Hsp90. This prevents the transfer of the unfolded protein between Hsp70 and Hsp90, and thus it inhibits Hsp90's role in folding. With Hsp90 no longer folding proteins, large amounts of unfolded protein are produced, which effectivley leads to programmed cell death.
Furthermore, the SMX inbhitors induce high levels of cell death in cancer cells over normal cells, showing a 3 fold selectivity, while the clinic drug does not. All of these positive outcomes are likely related to the fact that SMX inhibitors modulate the C-terminus, while the clinic/classical drugs control ATP from binding to Hsp90 during the folding cycle. Desiging new and higly soluble analogs ofr mouse model and cancerous tissue studies is a project that is currently underway in our lab.
(b) Synthesis of Heat shock protein 27 (Hsp27) inhibitors
HSP27 is an ATP-independent molecular chaperone, whose sequence is highly conserved compared to other HSPs. HSP27 contains a conserved α-crystallin domain, a highly flexible but conserved C-terminus, and a highly variable N-terminus. The protein typically exists as large polydisperse oligomers (sizes up to 800 kDa, 29-mers) with the average size being 14-mers. The size of the oligomers is dependent on multiple physicochemical parameters including temperature, pH and degree of protein phosphorylation.
When subjected to physicochemical stress, HSP27 protein levels not only increase in order to facilitate folding the large number of proteins that require protein-folding and de-aggregation, but is also phosphorylated (see figure below). Recent work has shown that the phosphorylation of serines 15, 78, and 82, drives the equilibrium of oligomers to dimers. The dimers are the active form of the protein, and are responsible for folding and de-aggregating proteins, that is, the chaperone activity. For Parkinson’s, ALS and Alzheimer’s, driving the equilibrium to dimers to promote chaperone activity is optimal. For cancer, trapping the monomer is optimal as it will have no chaperone activity and hence, proteins will aggregate in the cell, promoting apoptosis. Thus, our work is focusing on generating molecules that inhibit the dimer and oligomer formation, whereby we trap the monomer and inhibit the aggregation back into the dimer. This project involves synthesizing numerous inhibitors based on that are focused on specific regions of Hsp27 sequence.
(c) Synthesis and mechanism studies of Marthiapeptide A
Marthiapeptide A is a natural product that is extremely potent at inhibiting cancer cell growth (nanomolar potency). Our goal is to synthesize and investigate its potential as an anti-cancer therapy. We have developed a successful route for making the natural product. This project involves making derivatives, and investigating the structure-activity relationships and their mechanism of action. Inverting the stereochemistry on the peptide side chains is well established by our lab to impact the ring conformation and hence biological activity. Thus, derivatives will focus on how modifying these side chains, both stereochemical and structural changes, impacts biological activity. Eavluaing the compounds in a series of appropriate biological assays will provide evidence of which compounds are the most effective.
(d) Synthesis of heat shock protein 70 (Hsp70) inhibitors- mimicking TPR1 domain
Cancer cells overexpress heat shock proteins (hsps), and specifically high levels of heat shock protein 70 (up to 10 fold) in order to facilitate their unrestrained growth. Indeed, cancer cells are dependent on Hsps for survival, and inhibition of Hsp90 or Hsp70 has proven toxic to cancer cells but not normal cells. This specific toxicity to cancer cells indicates that Hsp inhibitors could provide new, targeted cancer therapies, and recent success with both Hsp90 and Hsp70 inhibitors provides promising preliminary data. Most studies have focused on Hsp90 inhibitors, and there are numerous clinical trials currently testing inhibitors. However, Hsp70 appears to be more critical than Hsp90 to the cell under stressed conditions, hence Hsp70 may be a highly effective chemotherapeutic target.
Hsp70 has a highly conserved structure consisting of a nucleotide-binding domain (NBD), which binds ATP and a substrate-binding domain (SBD), which binds the proteins that require Hsp70 chaperone function; both domains have been targeted as sites for inhibiting Hsp708. The interaction of Hsp70 with other proteins such as HOP (heat shock organizing protein) (see figure) is an opportunity to block the primary function of Hsp70. By binding to Hsp70 and inhibiting it’s interaction with HOP, one can inhibit the protein folding process, and thereby induce large amounts of unfolded protein. Once the cell is overwhelmed with unfolded protein it goes into apoptosis, or programed cell death. Currently we are designing molecules that mimic the TPR1 site on HOP, with the goal that this mimic will bind to Hsp70 and block its ability to interact with HOP. Work on this project will involve synthesizing molecules that mimic the TPR1 domain, focusing on the inclusion of specific residues that are critical for binding between Hsp70 and HOP.
(e) Studying heat shock protein 90 inhibitors that deplete heat shock proteins
There are three isoforms of Hsp90 found in cells: Hsp90A, Grp94 and TRAP-1. Hsp90A is the cytosol Hsp90; Grp94 is located in the endoplasmic reticulum (ER); TRAP-1 is the Hsp90 isoform found in the mitochondria. The ER is responsible for synthesis, modification and delivery of proteins, and any disruption of the process will cause ER stress. Grp94 is up-regulated when the ER is under stress, in order to manage the accumulation of unfolded or mis-folded proteins that are induced when the cell is stressed. Recent evidence in the McAlpine lab has suggested that the SM series may target Grp94 and/or Hsp90A (i.e. the ER and cytosol Hsp90 isoforms). Thus, this project investigates the hypothesis that the SMX inhibitors of Hsp90 in the cytotsol also control Grp94.
The overall goal of the project is to define the mechanism of action of Hsp90 inhibitors SM253 and SM258 (see Figure) and to understand if these compounds target one or both of the Hsp90 isoforms (Grp94 and/or Hsp90A). Using techniques described in the figure (steps 1-4) we will evaluate the roles of two Hsp90 isoforms, Hsp90A and Grp94 for inducing the heat shock response in the colon cancer cell line HCT116. Then we will identify the specific isoform of Hsp90 that is targeted by SM253, SM258 and the classic inhibitors 17-AAG and AUY922 (controls). Finally this project will determine if there is a connection to the reduction in the heat shock response for the SMX inhibitors and the increase in this heat shock reponse with the classic inhibitors.
f) Synthesis of Heat Shock Protein 90 (Hsp90) inhibitors- mimicing the TPR2A domain
Heat shock proteins are in charge of folding and maintaining over 400 proteins in the cell. Blocking heat shock protein 90’s (Hsp90’s) ability to fold these proteins in cancer cells damages the cells, and pushes the cells into programmed cell death. This project involves synthesizing molecules that mimic the TPR2A domain on the protein HOP, called TPR mimics. In this project we are investigating whether these molecules inhibit Hsp90 interacting with HOP via a direct binding interaction with Hsp90. Our lab has shown that designing molecules that target the MEEVD region is highly effective for blocking the interaction between Hsp90 and TPR-containing proteins like HOP. This project involves synthesizing molecules that mimic the TPR domain, and with the goal of also produced cell permeable molecules. Specifically, once the molecules are optimized for binding to the MEEVD region, masking groups are being placed on the polar side changes in order to allow the compounds to enter the cell , and then be revealed once in the cytosol.
(g) Investigating the mechanism of how Hsp90 inhibitors impact heat shock factor-1 (HSF-1) levels
The role that heat shock factor 1 (HSF-1) plays in regulating cellular stress has been generally established. HSF-1 is overexpressed in numerous cancer types, including: breast, prostate, kidney, colon and nerve sheath and this overexpression is correlated with increased malignancy and mortality. The negative impact of high HSF-1 levels is obvious in patients, where high cellular levels of HSF-1 indicate a poor prognosis for the patient. HSF-1’s primary role is to protect a cell when it is under stress. Since cancer cells are constantly in a state of stress, HSF-1 manages the stress levels of the cell, which facilitates tumour cell survival.
Classic Hsp90 inhibitors induce the HSR, which includes increasing HSF-1 protein levels by 5-6 fold over background, which indicates the need for other types of inhibitors. Several SMX compounds developed in our lab completely deplete the HSF-1 protein in drug-treated cells. This project focuses on the development of compounds that deplete HSF-1 levels in cells, and understanding the connection between Hsp90 inhibition via the SMX mechanism and the corresponding reduction in HSF-1 protein levels.
(h) Mechanism studies on heterocyclic fragments
Linked azoles are unique substructures that are present in many natural products (see figure). Over the past two decades there has been a surge in the discovery of natural product compounds that contain linked azoles and many of these compounds are now candidates for dug development. Urukthapelstatin A (Ustat A) is a natural product isolated from marine bacteria and it shows potent anticancer activity against a panel of human cancer cell lines, with an average IC50 value of 12 nM.22-24 This molecule has a unique bisoxazole and bisthiazole moiety located within the macrocycle. HXDV is a synthetic derivative of telomestatin, and it exhibits anti-proliferative and apoptotic activity by stabilizing the G-quadruplex, thereby inducing M-phase cell cycle arrest.25-26 It has two linked tri-oxazoles within its macrocyclic backbone. Marthiapeptide A is another potent natural product that contains a linked trithiazole-thiazoline system, and cytotoxicity with an IC50 = ~380-520 nM against a panel of cancer cell lines.
Inspired by the linked azoles observed within these three biologically active molecules and the activity of linked azole molecules we have previously reported, we designed a series of linked thiazoles and oxazoles with both R and S stereochemistry at the tail end of the molecule, since all 3 natural products have a substituent at this position. The top portion of the molecule required a capping agent, and we investigated three different moieties including ester, amide and thioamide. We found that thiazoles were the most effective at inhibiting cell growth, and inducing apoptosis, and had low µM GI50 values (versus oxazoles that had no effect). Curently this project involves synthesizing thiazole analogs with modifications to the stereochemistry at the tail end of the compound, and the capping group. Testing these compounds in biological assays could show that the ring structure is unnecessary to produce highly potent compounds.
here. ∞ = Invited and peer reviewed Book Chapter ‡ = these two authors contributed equally65. Thioimidazoline based compounds reverse glucocorticoid resistance in acute lymphoblastic leukemia cells Cara Toscan, Marwa Rahimi, Mohan Bhadbhade, Russell Pickford, Shelli R. McAlpine* and Richard Lock* In Press Org. Biomol. Chem. April 24, 2015 DOI: 10.1039/C5OB00779H 64. Predicating the unpredictable: recent examples of biologically active heterocycle-containing macrocycles Hendra Wahyudi and Shelli R. McAlpine* In Press Bioorganic Chemistry April 22, 2015 63. Activation of the Nuclear Factor kB inducing kinase inducing kinase as a mechanism of beta cell failure in obesity Elisabeth K. Malle, Nathan W. Zammit, Stacey N. Walters, Yen Chin Koay,Jianmin, Wu, Bernice, M. Tan, Jeanette E. Villanueva, Robert Brink, Tom Loudovaris, James Cantley, Shelli R. McAlpine, Daniel Hesselson, Shane T. Grey* In press Journal of Experimental Medicine : 201562. Heat shock protein 27: structure, function, cellular Role and inhibitors Rashid Mehmood* and Shelli R. McAlpine* In Press Springer Books: “Heat shock Proteins: Success Stories” (accepted April 15, 2015)61. Targeting the c-terminus of heat shock protein 90 as a cancer therapy Jeanette R McConnell, Yao Wang, Shelli R. McAlpine* In Press Springer Books: “Heat shock Proteins: Success Stories” (accepted March 1, 2015)60. C-terminal heat shock protein 90 modulators produce desirable oncogenic properties Yao Wang and Shelli R. McAlpine* Org. Biomol. Chem:V13, 4627-4631 2015ON THE COVER OF ORG. BIOMOL. CHEM.59. Combining an Hsp70 inhibitor with either an N-terminal and C-terminal hsp90 inhibitor produces mechanistically distinct phenotypes Yao Wang and Shelli R. McAlpine* Org. Biomol. Chem. V13, 3691-3698