epidermal-growth-factor and Carcinoma--Medullary

Basal-like carcinomas and human epidermal growth factor receptor 2 (HER-2/neu) overexpression carcinomas are the subgroups of breast cancers that have the most aggressive clinical behavior. Phosphorylation/activation of c-Jun NH2-terminal kinase is characterized as a stress-activated protein kinase, which regulates apoptosis after cellular stress. The aim of this study was to evaluate the association of phosphorylated c-Jun NH2-terminal kinase expression with phenotypes and clinicopathologic parameters of breast cancer. Phosphorylated c-Jun NH2-terminal kinase was immunohistochemically measured in a cohort of 160 patients with invasive breast cancer treated with therapeutic surgery followed by anthracycline or docetaxel-based chemotherapy. These results were further correlated with the phenotypes and clinicopathologic characteristics of breast cancers. Increased phosphorylated c-Jun NH2-terminal kinase expression was significantly associated with lack of estrogen receptor expression (P < .0001), positivity for cytokeratins 5/6 (P = .029), epidermal growth factor receptor (P = .035), basal-like phenotype (P = .015), and "triple-negative" phenotype (P = .01). Furthermore, the positive expression of phosphorylated c-Jun NH2-terminal kinase was positively correlated with p-glycoprotein (r = 0.54, P < .0001) and multidrug resistance-associated protein 1(r = 0.38, P < .0001) but not with lung resistance protein (r = -0.02, P = .78). Our results indicate that the activation of phosphorylated c-Jun NH2-terminal kinase may play a role in the carcinogenesis of basal-like and triple-negative breast carcinoma.

Topics: Adenocarcinoma, Mucinous; ATP Binding Cassette Transporter, Subfamily B, Member 1; Breast Neoplasms; Carcinoma, Ductal, Breast; Carcinoma, Lobular; Carcinoma, Medullary; Chi-Square Distribution; Epidermal Growth Factor; Estrogen Receptor alpha; Female; Humans; Immunohistochemistry; JNK Mitogen-Activated Protein Kinases; Keratins; Multidrug Resistance-Associated Proteins; Neoplasm Staging; Patient Selection; Phosphorylation; Up-Regulation; Vault Ribonucleoprotein Particles

Proteomics may help to elucidate differential signaling networks underlying the effects of compounds and to identify new therapeutic targets. Using a proteomic-multiplexed analysis of the phosphotyrosine signaling together with antibody-based validation techniques, we identified several candidate molecules for RET (rearranged during transfection) tyrosine kinase receptor carrying mutations responsible for the multiple endocrine neoplasia type 2A and 2B (MEN2A and MEN2B) syndromes in two human medullary thyroid carcinoma (MTC) cell lines, TT and MZ-CRC-1, which express the RET-MEN2A and RET-MEN2B oncoproteins, respectively. Signaling elements downstream of these oncoproteins were identified after treating cells with the indolinone tyrosine kinase inhibitor RPI-1 to knock down RET phosphorylation activity. We detected 23 and 18 affinity-purified phosphotyrosine proteins in untreated TT and MZ-CRC-1 cells, respectively, most of which were shared and sensitive to RPI-1 treatment. However, our data clearly point to specific signaling features of the RET-MEN2A and RET-MEN2B oncogenic pathways. Moreover, the detection of high-level expression of minimally phosphorylated epidermal growth factor receptor (EGFR) in both TT and MZ-CRC-1 cells, together with our data on the effects of EGF stimulation on the proteomic profiles and the response to Gefitinib treatment, suggest the relevance of EGFR signaling in these cell lines, especially since analysis of 14 archival MTC specimens revealed EGFR mRNA expression in all samples. Together, our data suggest that RET/EGFR multi-target inhibitors might be beneficial for therapy of MTC.

Topics: Animals; Antineoplastic Agents; Carcinoma, Medullary; Epidermal Growth Factor; ErbB Receptors; Female; Gefitinib; Germ-Line Mutation; Humans; Mice; Mice, Nude; Multiple Endocrine Neoplasia Type 2a; Multiple Endocrine Neoplasia Type 2b; Oncogene Proteins; Phosphorylation; Proteomics; Proto-Oncogene Proteins c-ret; Quinazolines; Signal Transduction; Thyroid Neoplasms; Tyrosine