pf-00299804 and Breast-Neoplasms

Heterocyclic rings such as thiazole and benzimidazole are considered as privileged structures, since they constitute several FDA-approved drugs for cancer treatment. In this work, a new set of 2-(2-(substituted) hydrazinyl)-4-(1-methyl-1H-benzo[d]imidazol-2-yl) thiazoles 4a-q were designed as epidermal growth factor receptor (EGFR) inhibitors and synthesized using concise synthetic methods. The new target compounds have been evaluated in vitro for their suppression activity against EGFR TK. Compounds 4n, 4h, 4i, 4a and 4d exhibited significant potency in comparison with erlotinib which served as a reference drug (IC50, 71.67-152.59 nM; IC50 erlotinib, 152.59 nM). Furthermore, MTT assay revealed that compounds 4j, 4a, 4f, 4h, 4n produced the most promising cytotoxic potency against the human breast cancer cell line (MCF-7) (IC50; 5.96-11.91 µM; IC50 erlotinib; 4.15 µM). Compound 4a showed promising activity as EGFR TK inhibitor as well as anti-breast cancer agent. In addition, 4a induced apoptotic effect and cell cycle arrest at G2/M phase preventing the mitotic cycle in MCF-7 cells. Moreover, 4a upregulated the oncogenic parameters; caspase-3, p53, Bax/Bcl-2 as well as it inhibited the level of PARP-1 enzyme. QSAR study was carried out for the new derivatives and it revealed the goodness of the models. Furthermore, molecular docking studies represented the binding modes of the promising compounds in the active pocket of EGFR.

Topics: Antineoplastic Agents; Apoptosis; Benzimidazoles; Breast Neoplasms; Cell Proliferation; Drug Screening Assays, Antitumor; ErbB Receptors; Erlotinib Hydrochloride; Female; Humans; MCF-7 Cells; Molecular Docking Simulation; Protein Kinase Inhibitors; Quantitative Structure-Activity Relationship; Thiazoles

Despite the development of novel targeted therapies, de novo or acquired chemoresistance remains a significant factor for treatment failure in breast cancer therapeutics. Neratinib and dacomitinib are irreversible panHER inhibitors, which block their autophosphorylation and downstream signaling. Moreover, neratinib and dacomitinib have been shown to activate cell death in HER2-overexpressing cell lines. Here we showed that increased MCL1 and decreased BIM and PUMA mediated resistance to neratinib in ZR-75-30 and SKBR3 cells while increased BCL-XL and BCL-2 and decreased BIM and PUMA promoted neratinib resistance in BT474 cells. Cells were also cross-resistant to dacomitinib. BH3 profiles of HER2+ breast cancer cells efficiently predicted antiapoptotic protein dependence and development of resistance to panHER inhibitors. Reactivation of ERK1/2 was primarily responsible for acquired resistance in SKBR3 and ZR-75-30 cells. Adding specific ERK1/2 inhibitor SCH772984 to neratinib or dacomitinib led to increased apoptotic response in neratinib-resistant SKBR3 and ZR-75-30 cells, but we did not detect a similar response in neratinib-resistant BT474 cells. Accordingly, suppression of BCL-2/BCL-XL by ABT-737 was required in addition to ERK1/2 inhibition for neratinib- or dacomitinib-induced apoptosis in neratinib-resistant BT474 cells. Our results showed that different mitochondrial apoptotic blocks mediated acquired panHER inhibitor resistance in HER2+ breast cancer cell lines as well as highlighted the potential of BH3 profiling assay in prediction of panHER inhibitor resistance in breast cancer cells.

Topics: bcl-X Protein; Benzothiazoles; Biphenyl Compounds; Breast Neoplasms; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Cell Proliferation; Cell Survival; Drug Resistance, Neoplasm; Female; Gene Expression Regulation, Neoplastic; Humans; Indazoles; Isoquinolines; Nitrophenols; Piperazines; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-bcl-2; Quinazolinones; Quinolines; Receptor, ErbB-2; Sulfonamides

HER2 tyrosine kinase receptor is a validated target in breast cancer therapy. However, increasing evidence points to a major role of Δ16HER2 splice variant commonly coexpressed with HER2 and identified as a clinically important HER2 molecular alteration promoting aggressive metastatic breast cancer. Consistently, mice transgenic for the human Δ16HER2 isoform (Δ16HER2 mice) develop invasive mammary carcinomas with early onset and 100% penetrance. The present study provides preclinical evidence that Δ16HER2 expression confers de novo resistance to standard anti-HER2-therapies such as Lapatinib and acquired resistance to the selective Src inhibitor Saracatinib in breast cancer. Of note, Dacomitinib, an irreversible small molecule pan-HER inhibitor, was able to completely suppress Δ16HER2-driven breast carcinogenesis. Thus, only Dacomitinib may offer benefit in this molecularly defined patient subset by irreversibly inhibiting Δ16HER2 activation.

Topics: Alternative Splicing; Animals; Benzodioxoles; Breast Neoplasms; Cell Line, Tumor; Cell Survival; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Female; Genetic Predisposition to Disease; Humans; Inhibitory Concentration 50; Lapatinib; Mammary Neoplasms, Experimental; Mice, Transgenic; Phenotype; Protein Isoforms; Protein Kinase Inhibitors; Quinazolines; Quinazolinones; Receptor, ErbB-2; Signal Transduction; Time Factors

The human EGF (HER) family of receptors has been pursued as therapeutic targets in breast cancer and other malignancies. Trastuzumab and lapatinib are standard treatments for HER2-amplified breast cancer, but a significant number of patients do not respond or develop resistance to these drugs. Here we evaluate the in vitro activity of dacomitinib (PF-00299804), an irreversible small molecule pan-HER inhibitor, in a large panel of human breast cancer cell lines with variable expression of the HER family receptors and ligands, and with variable sensitivity to trastuzumab and lapatinib. Forty-seven human breast cancer and immortalized breast epithelial lines representing the known molecular subgroups of breast cancer were treated with dacomitinib to determine IC(50) values. HER2-amplified lines were far more likely to respond to dacomitinib than nonamplified lines (RR, 3.39; P < 0.0001). Furthermore, HER2 mRNA and protein expression were quantitatively associated with response. Dacomitinib reduced the phosphorylation of HER2, EGFR, HER4, AKT, and ERK in the majority of sensitive lines. Dacomitinib exerted its antiproliferative effect through a combined G(0)-G(1) arrest and an induction of apoptosis. Dacomitinib inhibited growth in several HER2-amplified lines with de novo and acquired resistance to trastuzumab. Dacomitinib maintained a high activity in lines with acquired resistance to lapatinib. This study identifies HER2-amplified breast cancer lines as most sensitive to the antiproliferative effect of dacomitinib and provides a strong rationale for its clinical testing in HER2-amplified breast cancers resistant to trastuzumab and lapatinib.

Topics: Antibodies, Monoclonal, Humanized; Antineoplastic Agents, Hormonal; Apoptosis; Breast Neoplasms; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Drug Resistance, Neoplasm; Female; Gene Amplification; Humans; Inhibitory Concentration 50; Lapatinib; Neoplasms, Hormone-Dependent; Phosphorylation; Protein Processing, Post-Translational; Quinazolines; Quinazolinones; Receptor, ErbB-2; Receptors, Estrogen; Signal Transduction; Trastuzumab