HER2 expression is predictive of survival in cetuximab treated patients with RAS wild type metastatic colorectal cancer

The overexpressed HER2 is an important target for treatment with monoclonal antibody (mAb) trastuzumab, only in patients with breast and gastric cancers, and is an emerging therapeutic biomarker in metastatic colorectal cancer (mCRC) treated with anti-epidermal growth factor receptor (EGFR) mAbs cetuximab and panitumumab. In this study, we investigated the relative expression and predictive value of all human epidermal growth factor receptor (HER) family members in 144 cetuximab-treated patients with wild type RAS mCRC. The relative expression of EGFR and HER2 have also been examined in 21-paired primary tumours and their metastatic sites by immunohistochemistry. Of the 144 cases examined, 25%, 97%, 79%, 48%, and 10% were positive for EGFR, HER2, HER3, and HER4 and all four HER family members, respectively. The expression of EGFR was an indicator of poorer overall survival and the membranous expression of HER2 and HER3 3+ intensity was associated with a shorter progression free survival (PFS). In contrast, the cytoplasmic expression of HER2 was associated with better PFS. In 48% and 71% of the cases, there were discordance in the expression of EGFR or one or more HER family members in paired primary and related metastatic tumours, respectively. Our results implicate the importance of a large prospective investigation of the expression level and predictive value of not only the therapeutic target (i.e., EGFR protein) but also HER2 and other HER family members as therapeutic targets, or for response to therapy with anti-EGFR mAbs and other forms of HER inhibitors, in both the primary tumours and metastatic sites in mCRC

Impact of the putative cancer stem cell markers and growth factor receptor expression on the sensitivity of ovarian cancer cells to treatment with various forms of the HER inhibitors and cytotoxic drugs

Increased expression and activation of human epidermal growth factor receptor (EGFR) and HER-2 have been reported in numerous cancers. The aim of this study was to determine the sensitivity of a large panel of human ovarian cancer cell lines (OCCLs) to treatment with various forms of small molecule tyrosine kinase inhibitors (TKIs) and cytotoxic drugs. The aim was to see if there was any association between the protein expression of various biomarkers including three putative ovarian cancer stem cell (CSC) markers (CD24, CD44, CD117/c-Kit), P-glycoprotein (P-gp), and HER family members and response to treatment with these agents. The sensitivity of 10 ovarian tumour cell lines to the treatment with various forms of HER TKIs (gefitinib, erlotinib, lapatinib, sapitinib, afatinib, canertinib, neratinib), as well as other TKIs (dasatinib, imatinib, NVP-AEW541, crizotinib) and cytotoxic agents (paclitaxel, cisplatin and doxorubicin), as single agents or in combination, was determined by SRB assay. The effect on these agents on the cell cycle distribution, and downstream signaling molecules and tumour migration were determined using flow cytometry, western blotting, and the IncuCyte Clear View cell migration assay respectively. Of the HER inhibitors, the irreversible pan-TKIs (canertinib, neratinib and afatinib) were the most effective TKIs for inhibiting the growth of all ovarian cancer cells, and for blocking the phosphorylation of EGFR, HER-2, AKT and MAPK in SKOV3 cells. Interestingly, while the majority of cancer cells were highly sensitive to treatment with dasatinib, they were relatively resistant to treatment with imatinib (i.e., IC50 >10 µM). Of the cytotoxic agents, paclitaxel was the most effective for inhibiting the growth of OCCLs, and of various combinations of these drugs, only treatment with a combination of NVP-AEW541 and paclitaxel produced a synergistic or additive anti-proliferative effect in all three cell lines examined (i.e., SKOV3, Caov3, ES2). Finally, of the TKIs, only treatment with afatinib, neratinib and dasatinib were able to reduce the migration of HER-2 overexpressing SKOV3 cells. We did not find any significant association between the expression of putative ovarian CSC marker, HER family members, c-MET, ALK, and IGF-IR and the response to the irreversible HER TKIs. Our results support the need for further investigations of the therapeutic potential of these irreversible HER family blockers in ovarian cancer, and the therapeutic potential of dasatinib when used in combination with the inhibitors of the HER family members in ovarian cancer

Growth factor receptors, cancer stem cells and drug resistance antigens : their roles in the progression of ovarian cancer and response to therapeutics

Ovarian cancer is one of the most aggressive and lethal types of gynaecological cancer. In the past two decades, increased expression and activation of HER (human epidermal growth factor receptor) family members have been reported in a wide range of epithelial tumours, and in some studies they have been associated with a poorer prognosis. To date, several monoclonal antibodies and small molecule tyrosine kinase inhibitors (TKis) specific for the HER members have been approved for the treatment of patients with a wide range of tumours, but none has yet been approved for the treatment of patients with ovarian cancers. The aim of this study was to determine the sensitivity of a large panel of human ovarian cancer cell lines (OCCLs) to treatment with various forms of HER tyrosine kinase inhibitors (TKis), including reversible EGFR specific, and reversible and irreversible pan-ErbB family inhibitors. In addition, the effect of other inhibitors including Dasatinib (v-abl/src/c-KIT TKI), Imatinib (v-abl/c-KIT/PDGFR TKI), NVP-AEW541 (I GF-1 R inhibitor), Crizotinib ( c-MET / ALKinhibitor) and cytotoxic agents (pacl itaxel, cisplatin and doxorubicin) on the growth of OCCLs was investigated. Any association between the expression of various biomarkers, such as the putative ovarian cancer stem cell (CSC) markers (e.g. CD24, CD44, and CDl 17/c-KIT), P-Glycoprotein (Pgp), and HER family members and their responses to treatment with these agents were examined. Of the HER inhibitors, the irreversible pan-TKis ( canertinib, neratinib and afatinib) were the most effective TKI's for inhibiting the growth of all OCCLs, and for blocking the phosphorylation of EGFR, HER-2, AKT and MAPK in SKOV3 cells. Interestingly, while the majority of cancer cells were highly sensitive to treatment with dasatinib, they were relatively resistant to treatment with imatinib (i.e. IC50> 10 µM). Of the cytotoxic agents, paclitaxel was the most effective for inhibiting the growth of OCCLs, and of various combinations of these drugs, only treatment with a combination of NVP-AEW541 and paclitaxel produced a synergistic or additive anti-proliferative effect in all three cell lines examined (i.e. SKOV3, Caov3 and ES2). Of the TKis, only treatment with afatinib, neratinib and dasatinib were able to reduce the migration of HER-2 overexpressing SKOV3 cells. Interestingly, while acquired resistant of ovarian cancer cells to treatment with afatinib and dasatinib was accompanied by cross-resistance to other TKis, such resistant variants become more sensitive to killing by cytotoxic drugs. No signification association was found between the expression of putative ovarian CSC markers, HER family members, and other markers on the response to the treatment with the TKis. The expression pattern and prognostic significance of the HER-family members, EGFRvIII, CD44, IGF-lR, c-MET and Ki67 were also examined in tumour specimens from 60 FIGO stage III and IV ovarian cancer patients. The expression of EGFR, HER-2, HER-4, c-MET, CD44 and Ki67 was found to be common in patients with FIGO stage III and IV ovarian cancer. EGFR and CD44 expression at cut-off values of >50% and >50% of tumour cells with positive staining were associated with poorer overall survival, whilst Ki67 at cut off value of >5% was associated with fav6urable overall survival. In conclusion, the results presented support the need for further investigations of the therapeutic potential of the irreversible HER family blockers in ovarian cancer, and the therapeutic potential of dasatinib when used in combination with the inhibitors of the HER family members