Virtual screening, molecular dynamics simulations, and in vitro validation of EGFR inhibitors as breast cancer therapeutics.

A high abundance of Epidermal Growth Factor Receptor (EGFR) in malignant cells makes them a prospective therapeutic target for basal breast tumors. Although EGFR inhibitors are in development as anticancer therapeutics, there exists limitations due to the dose-limiting cytotoxicity that limits their clinical utilization, thereby necessitating the advancement of effective inhibitors. In the present study, we have developed common pharmacophore hypotheses using 30 known EGFR inhibitors. The best pharmacophore hypothesis DHRRR_1 was utilized for virtual screening (VS) of the Phase database containing 4.3 × 106 fully prepared compounds. The top 1000 hits were further subjected to ADME filtration followed by structure-based VS and Molecular Dynamics (MD) simulation investigations. Based on pharmacophore hypothesis matching, XP glide score, interactions between ligands and active site residues, ADME properties, and MD simulations, the five best hits (SN-01 through SN-05) were preferred for in-vitro cytotoxicity studies. All the molecules except SN-02 exhibited cytotoxicity in Triple Negative Breast Cancer (TNBC) cells. These potential EGFR inhibitors effectively downregulated the EGF-induced proliferation, migration, in-vitro tumorigenic capability, and EGFR activation (pEGFR) in the TNBCs. Additionally, in combination with doxorubicin, the identified EGFR inhibitors significantly decreased the EGF-induced proliferation. SN-04, and SN-05 in the presence of a lower concentration of doxorubicin markedly increased the apoptotic markers expression in the TNBCs, an effect which was comparable to a higher concentration of doxorubicin treatment, alone. These observations suggest that both SN-04 and/or SN-05 can improve the efficacy of chemotherapeutic drug, doxorubicin at a lower concentration to avert the higher dose of chemotherapeutic-induced side effects during breast cancer treatment.

Epidermal growth factor receptor inhibition potentiates chemotherapeutics-mediated sensitization of metastatic breast cancer stem cells.

BACKGROUND: Metastasis has been a cause of the poor prognosis and cancer relapse of triple-negative breast cancer (TNBC) patients. The metastatic nature of TNBC is contributed by the breast cancer stem cells (CSCs) which have been implicated in tumorigenesis. Higher expression of epidermal growth factor receptor (EGFR) in breast CSCs has been used as a molecular target for breast cancer therapeutics. Thus, it necessitates the design and generation of efficacious EGFR inhibitors to target the downstream signaling associated with the cellular proliferation and tumorigenesis of breast cancer. AIM: To generate efficacious EGFR inhibitors that can potentiate the chemotherapeutic-mediated mitigation of breast cancer tumorigenesis. METHODS AND RESULTS: We identified small molecule EGFR inhibitors using molecular docking studies. In-vitro screening of the compounds was undertaken to identify the cytotoxicity profile of the small-molecule EGFR inhibitors followed by evaluation of the non-cytotoxic compounds in modulating the doxorubicin-induced migration, in-vitro tumorigenesis potential, and their effect on the pro-apoptotic genes' and protein markers' expression in TNBC cells. Compound 1e potentiated the doxorubicin-mediated inhibitory effect on proliferation, migration, in-vitro tumorigenesis capacity, and induction of apoptosis in MDA-MB-231 cells, and in the sorted CD24+-breast cancer cells and CD24-/CD44+-breast CSC populations. Orthotopic xenotransplantation of the breast CSCs-induced tumors in C57BL/6J mice was significantly inhibited by the low dose of Doxorubicin in the presence of compound 1e as depicted by molecular and immunohistochemical analysis. CONCLUSION: Thus, the study suggests that EGFR inhibition-mediated sensitization of the aggressive and metastatic breast CSCs in TNBCs toward chemotherapeutics may reduce the relapse of the disease.

Recent Advances on Epidermal Growth Factor Receptor as a Molecular Target for Breast Cancer Therapeutics.

Epidermal Growth Factor Receptor (EGFR), a type-I transmembrane protein with intrinsic tyrosine kinase activity, is activated by peptide growth factors such as EGF, epigen, amphiregulin, etc. EGFR plays a vital role in regulating cell growth, migration, and differentiation in various tissue-specific cancers. It has been reported to be overexpressed in lung, head, and neck, colon, brain, pancreatic, and breast cancer that triggers tumor progression and drug resistance. EGFR overexpression alters the signaling pathway and induces cell division, invasion, and cell survival. Our prior studies demonstrated that EGFR inhibition modulates chemosensitivity in breast cancer stem cells, thereby serving as a potential drug target for breast cancer mitigation. Tyrosine kinase inhibitors (Lapatinib, Neratinib) and monoclonal antibodies (Trastuzumab) targeting EGFR have been developed and approved by the US FDA for clinical use against breast cancer. This review highlights the critical role of EGFR in breast cancer progression and enumerates the various approaches being undertaken to inhibit aggressive breast cancers by suppressing the downstream pathways. Furthermore, the mechanisms of action of potential molecules at various stages of drug development, as well as clinically approved drugs for breast cancer treatment, are illustrated.