Periodic Reporting for period 1 - Src dimerization (Activation of Src kinases through dimerization suggests novel therapeutic opportunities)
Période du rapport: 2020-06-01 au 2023-05-31
N-myristoyltransferases (NMTs) are enzymes catalyzing the transfer of myristic acid, a 14-carbon fatty acid, to specific cellular proteins. This process, known as myristoylation, enables the anchoring of these proteins to cellular membranes. NMTs are essential for the survival of parasitic protozoan organisms and tumour cells, making them attractive targets for the treatment of devastating diseases such as malaria, African sleeping sickness, and cancer. Several NMT inhibitors have been developed and have shown promising results in preclinical models. However, despite their efficacy in these studies, these NMT inhibitors possess some undesirable pharmacological properties, such as suboptimal bioavailability and absorption, that may limit their clinical utilization.
Our first objective was focused on understanding the mechanism of NMT inhibition and conducting extensive screening to identify novel NMT inhibitors with improved pharmacological properties. The results provide valuable information about the design and development of the next-generation NMT inhibitors and could give novel treatment options for malaria and oncological diseases.
Our second objective was to investigate the significance of NMT-mediated myristoylation of the c-Src oncogene. Myristoylation facilitates c-Src association with cellular membranes, promotes dimerization between two Src molecules, and regulates its kinase activity. The NMT inhibitors may exert their anti-tumour activity, at least in part, by disrupting c-Src myristoylation and inhibiting its activity. However, the role of myristoylation and dimerization of c-Src in cancer remains poorly understood. Our findings revealed the deregulation of this process in cancer and that systemic activation of Src kinases plays a key role in the development of resistance mechanisms against anti-cancer therapies. Overcoming this resistant mechanism significantly improved therapy outcomes in colorectal cancer.
Our first objective was focused on understanding the mechanism of NMT inhibition and conducting extensive screening to identify novel NMT inhibitors with improved pharmacological properties. The results provide valuable information about the design and development of the next-generation NMT inhibitors and could give novel treatment options for malaria and oncological diseases.
Our second objective was to investigate the significance of NMT-mediated myristoylation of the c-Src oncogene. Myristoylation facilitates c-Src association with cellular membranes, promotes dimerization between two Src molecules, and regulates its kinase activity. The NMT inhibitors may exert their anti-tumour activity, at least in part, by disrupting c-Src myristoylation and inhibiting its activity. However, the role of myristoylation and dimerization of c-Src in cancer remains poorly understood. Our findings revealed the deregulation of this process in cancer and that systemic activation of Src kinases plays a key role in the development of resistance mechanisms against anti-cancer therapies. Overcoming this resistant mechanism significantly improved therapy outcomes in colorectal cancer.
This MSCA contains six Work Packages: 1) Management; 2) Training; 3) Research Objective 1; 4) Research Objective 2; 5) Grants; 6) Communication.
There were no notable problems or issues encountered in terms of scientific, financial, or administrative management of the project. The project provided me with valuable exposure to the field of drug design and offered extensive training opportunities in computational techniques for designing and optimizing potential drug candidates through the implementation of structure-based drug design methodologies. These methodologies encompassed the utilization of molecular docking, virtual screening, and molecular dynamics simulations to assess and enhance the efficacy of the candidate drug molecules.
Under Research Objective 1, our investigation focused on developing novel NMT inhibitors. To accomplish this objective, we initially studied the binding mode and mechanism through which the NMT inhibitors exert their inhibitory effects. It was discovered that the potent NMT inhibitors form a salt bridge with the negatively charged C-terminus of NMT through a positively charged chemical group. This interaction led to a remarkable activity enhancement of over 1,300-fold. These findings have been published in Frontiers in Molecular Biosciences (Front Mol Biosci. 2023, 9:1066029), providing valuable insights into the inhibitory mechanism of NMT inhibitors.
Next, our focus shifted to conducting a virtual screening of a vast compound library consisting of over 1.1 million compounds. By employing this approach, our aim was to identify promising candidates that could interact with NMT, replicating the observed binding mode characterized by salt bridge formation. Furthermore, the compounds were selected based on their pharmacological profiles to exhibit improved pharmacological properties. Based on these criteria, we selected 24 compounds for in vitro testing using purified N-myristoyltransferase in an NMT assay. Among these, we identify 7 compounds that are inhibitory to NMT. Further optimization of their structures is necessary to enhance their binding affinity and activity, a goal we plan to pursue in an upcoming project. The results from the virtual screening were published in the journal Molecules (Molecules. 2022 Aug 26;27(17):5478), providing valuable information about the design and development of the next-generation NMT inhibitors.
Under Research Objective 2, it was observed that the c-Src exhibited deregulation in cancer cells, resulting in enhanced dimerization and activity through its myristoylated N-terminal region. The results were published in the journal Molecular Cancer Research (Mol Cancer Res. 2021 Jun;19(6):957-967). Furthermore, increased Src activity was observed in colon cancer cells treated with anti-cancer drugs targeting BRAF and/or EGFR and this serves as a survival mechanism causing resistance to anti-cancer therapy. This resistance mechanism was mediated by a prostaglandin E2 loop, which could be effectively blocked using anti-inflammatory drugs - COX2 inhibitors. Combining BRAF inhibitors and COX2 inhibitors overcomes resistance to anti-cancer therapy and by inducing cell death in the cancer cells, substantially improved therapy outcomes in preclinical models. The results were published in Nature Cancer (Nat Cancer. 2023 Feb;4(2):240-256).
The project has produced 4 peer-reviewed articles. The findings were presented at two scientific conferences – i) 8th Congress of Pharmacy, April 27-30, 2023, Borovets, Bulgaria; and ii) UGM2023 conference in drug design, May 30- June 2, 2023 Munich, Germany; and were also communicated in events and platforms aiming to reach a broader audience. We obtained a grant from the European Union-NextGenerationEU program under the National Recovery and Resilience Plan of the Republic of Bulgaria. The upcoming work under this project will serve as a continuation and further development of the results achieved during the MSCA.
There were no notable problems or issues encountered in terms of scientific, financial, or administrative management of the project. The project provided me with valuable exposure to the field of drug design and offered extensive training opportunities in computational techniques for designing and optimizing potential drug candidates through the implementation of structure-based drug design methodologies. These methodologies encompassed the utilization of molecular docking, virtual screening, and molecular dynamics simulations to assess and enhance the efficacy of the candidate drug molecules.
Under Research Objective 1, our investigation focused on developing novel NMT inhibitors. To accomplish this objective, we initially studied the binding mode and mechanism through which the NMT inhibitors exert their inhibitory effects. It was discovered that the potent NMT inhibitors form a salt bridge with the negatively charged C-terminus of NMT through a positively charged chemical group. This interaction led to a remarkable activity enhancement of over 1,300-fold. These findings have been published in Frontiers in Molecular Biosciences (Front Mol Biosci. 2023, 9:1066029), providing valuable insights into the inhibitory mechanism of NMT inhibitors.
Next, our focus shifted to conducting a virtual screening of a vast compound library consisting of over 1.1 million compounds. By employing this approach, our aim was to identify promising candidates that could interact with NMT, replicating the observed binding mode characterized by salt bridge formation. Furthermore, the compounds were selected based on their pharmacological profiles to exhibit improved pharmacological properties. Based on these criteria, we selected 24 compounds for in vitro testing using purified N-myristoyltransferase in an NMT assay. Among these, we identify 7 compounds that are inhibitory to NMT. Further optimization of their structures is necessary to enhance their binding affinity and activity, a goal we plan to pursue in an upcoming project. The results from the virtual screening were published in the journal Molecules (Molecules. 2022 Aug 26;27(17):5478), providing valuable information about the design and development of the next-generation NMT inhibitors.
Under Research Objective 2, it was observed that the c-Src exhibited deregulation in cancer cells, resulting in enhanced dimerization and activity through its myristoylated N-terminal region. The results were published in the journal Molecular Cancer Research (Mol Cancer Res. 2021 Jun;19(6):957-967). Furthermore, increased Src activity was observed in colon cancer cells treated with anti-cancer drugs targeting BRAF and/or EGFR and this serves as a survival mechanism causing resistance to anti-cancer therapy. This resistance mechanism was mediated by a prostaglandin E2 loop, which could be effectively blocked using anti-inflammatory drugs - COX2 inhibitors. Combining BRAF inhibitors and COX2 inhibitors overcomes resistance to anti-cancer therapy and by inducing cell death in the cancer cells, substantially improved therapy outcomes in preclinical models. The results were published in Nature Cancer (Nat Cancer. 2023 Feb;4(2):240-256).
The project has produced 4 peer-reviewed articles. The findings were presented at two scientific conferences – i) 8th Congress of Pharmacy, April 27-30, 2023, Borovets, Bulgaria; and ii) UGM2023 conference in drug design, May 30- June 2, 2023 Munich, Germany; and were also communicated in events and platforms aiming to reach a broader audience. We obtained a grant from the European Union-NextGenerationEU program under the National Recovery and Resilience Plan of the Republic of Bulgaria. The upcoming work under this project will serve as a continuation and further development of the results achieved during the MSCA.
During the project, significant progress has been made in understanding the mechanism of inhibition of NMT, providing valuable insights for designing the second generation of NMT inhibitors. The NMT inhibitors show great potential for treating diseases like malaria, cancer, and other conditions. Their development is expected to have a significant socio-economic impact and broader societal implications, making them a promising avenue for medical advancements.
The findings also provide valuable insights into therapeutic resistance mechanisms in cancer. The synergistic effect between anti-inflammatory drugs and established targeted therapies in colon cancer holds significant clinical implications and life-saving potential, which will be determined in subsequent clinical trials.
The findings also provide valuable insights into therapeutic resistance mechanisms in cancer. The synergistic effect between anti-inflammatory drugs and established targeted therapies in colon cancer holds significant clinical implications and life-saving potential, which will be determined in subsequent clinical trials.