Computational insights into overcoming resistance mechanisms in targeted therapies for advanced breast cancer: focus on EGFR and HER2 co-inhibition.

In the present study, the formation of a heterodimer involving both epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) has been explored as a potential therapeutic mechanism to inhibit the progression of breast cancer. Virtual screening using molecular docking resulted in the three hit compounds (ZINC08382411, ZINC08382438, and ZINC08382292) with minimum binding scores and commonly binding to both receptors. Further, MD simulation analysis of these complexes illustrated the high stability of these compounds with EGFR and HER2. RMSD showed that ZINC08382411 displayed the most stable RMSD of 2 - 3 Å when bound to both receptors, suggesting to have strong compatibility with the active site of the receptor. Hydrogen bond analysis showed that ZINC08382411 forms the maximum number of H-bonds (2 to 3) in both EGFR and HER2 bound complexes, with the highest occupancy of 62% and 79%, respectively. Binding free energy calculation showed that ZINC08382411 possesses maximum affinity towards both the receptors with ΔGbind = -129.628 and -164.063 kJ/mol, respectively. This approach recognizes the significance of EGFR and HER2 in breast cancer development and aims to disrupt their collaborative signaling, which is known to promote the antagonistic behavior of cancer cells. By focusing on this EGFR/HER2 heterodimer, the study offers a promising avenue for identifying a potential candidate (ZINC08382411) that may inhibit breast cancer cell growth and potentially improve patient outcomes. The study's findings may contribute to the ongoing efforts to advance breast cancer treatment strategies.Communicated by Ramaswamy H. Sarma.

Breast cancer in patients with germline TP53 pathogenic variants have typical tumour characteristics: the Cohort study of TP53 carrier early onset breast cancer (COPE study).

Germline TP53 pathogenic variants are rare but associated with a high risk of cancer; they are often identified in the context of clinically diagnosed Li-Fraumeni syndrome predisposing to a range of young onset cancers including sarcomas and breast cancer. The study aim was to conduct a detailed morphological review and immuno-phenotyping of breast cancer arising in carriers of a germline TP53 pathogenic variant. We compared breast cancers from five defined groups: (1) TP53 carriers with breast cancer (n = 59), (2) early onset HER2-amplified breast cancer, no germline pathogenic variant in BRCA1/2 or TP53 (n = 55), (3) BRCA1 pathogenic variant carriers (n = 60); (4) BRCA2 pathogenic variant carriers (n = 61) and (5) young onset breast cancer with no known germline pathogenic variant (n = 98). Pathologists assessed a pre-agreed set of morphological characteristics using light microscopy. Immunohistochemistry (IHC) for HER2, ER, PR, p53, integrin alpha v beta 6 (αvß6) integrin, α-smooth muscle actin (α-SMA) and pSMAD2/3 was performed on tissue microarrays of invasive carcinoma. We confirmed a previously reported high prevalence of HER2-amplified, ductal no special type invasive breast carcinoma amongst known TP53 germline pathogenic variant carriers 20 of 36 (56%). Furthermore we observed a high frequency of densely sclerotic tumour stroma in cancers from TP53 carriers (29/36, 80.6%) when compared with non-carriers, 50.9% (28/55), 34.7% (50/144), 41.4% (65/157), 43.8% (95/217) in groups 2-5 respectively. The majority of germline TP53 gene carrier breast tumours had a high intensity of integrin αvß6, α-SMA and pSMAD2/3 expression in the majority of cancer cells. In conclusion, aggressive HER2 positive breast cancers with densely sclerotic stroma are common in germline TP53 carriers. High levels of αvß6 integrin, α-SMA and pSMAD2/3 expression suggest that the dense stromal phenotype may be driven by upregulated transforming growth factor beta signalling.