Author ORCID Identifier
Semester
Spring
Date of Graduation
2026
Document Type
Dissertation (Campus Access)
Degree Type
PhD
College
School of Pharmacy
Department
Pharmaceutical Sciences
Committee Chair
Yehenew Agazie
Committee Member
Benoit Driesschaert
Committee Member
Lori Hazlehurst
Committee Member
Sharan Bobbala
Committee Member
Werner Geldenhuys
Abstract
The Src homology 2 domain containing protein tyrosine phosphatase 2 (SHP2) is an oncogenic enzyme that is involved in positive regulation of receptor tyrosine kinase (RTK) signaling, cell transformation, and tumorigenesis in various cancer types including breast cancer. In this work, multiple series of active-site SHP2 inhibitors, classified as competitive and covalent inhibitors, were developed and tested. The design of the competitive inhibitors was based on peptide sequences derived from biological substrates of SHP2. In this class, the optimal compound named BPDA2 was developed, optimized, and tested under cell culture and in vivo conditions in HER2-positive breast cancer cells and tumor models. BPDA2 treatment of the HER2-amplified BT474 and Skbr3 breast cancer cells suppressed cell proliferation in 2D culture, blocked anchorage-independent growth in soft agar, and abolished mammosphere formation in suspension culture in a concentration-dependent manner. Furthermore, BPDA2 treatment blocked the expression of the primary oncogene HER2 and downregulated basal activation of ERK1/2 and Akt in a concentration-dependent manner as determined by their state of phosphorylation. To study the effects of SHP2 inhibition with BPDA2 in vivo, a more penetrating tumor model was generated by crossing MMTV-ErbB2 mice with p53-floxed and MMTV-Cre mice in order to achieve conditional p53 deletion in the mammary gland. These mice showed relatively shortened tumor latency compared to MMTV-ErbB2 mice and exhibited a greater rate of metastasis to the lungs and liver. In preparation for the efficacy studies, pharmacological properties of BPDA2 were determined using in vitro assays and in vivo experiments. The results showed that BPDA2 has a LogD7.4 of 0.61 ± 0.03 and is stable in liver S9 fractions for at least 6 hours. Furthermore, BPDA2 is rapidly absorbed into the blood when administered to mice at 40 mg/kg by oral gavage, and a plasma concentration of 2-4 µM is maintained for 6 hours. Tumor-bearing mice randomized into three groups were treated with vehicle, 20 mg/kg BPDA2, or 40 mg/kg BPDA2 by oral gavage every 3 days for 10 total treatments. The results showed suppression of tumor growth at 20 mg/kg and near-complete blockage of tumor growth at 40 mg/kg when compared to the vehicle group. These results demonstrate that targeting SHP2 with an active-site inhibitor is effective for the treatment of primary HER2-positive breast cancer. To further improve upon the results obtained with BPDA2, the development of covalent active-site SHP2 inhibitors has begun. The goals are to achieve greater potency and anti-cancer efficacy while maintaining selectivity. The synthesis methods and characterization of several of these compounds are reported here.
Recommended Citation
Mersch, James Edward, "Development of novel SHP2 active-site inhibitors and demonstration of efficacy in preclinical models of HER2-positive breast cancer" (2026). Graduate Theses, Dissertations, and Problem Reports. 13284.
https://researchrepository.wvu.edu/etd/13284