Investigation of molecular alterations of AKT-3 in triple-negative breast cancer.

AIMS: Triple-negative breast cancer (TNBC) is responsible for a disproportionate number of breast cancer (BC) deaths, owing to its intrinsic aggressiveness and a lack of treatment options, especially targeted therapies. Thus, there is an urgent need for the development of better targeted treatments for TNBC. Molecular alteration of AKT-3 was previously reported in oestrogen receptor (ER)-positive BC. AKT-3 has also been suggested to play a role in hormone-unresponsive BC. The aim of this study was to investigate molecular alterations of AKT-3 in TNBC, to perform associated survival analysis, and to compare these findings with the incidence of AKT-3 molecular alterations in ER-positive BC. RESULTS: Our study revealed AKT-3 amplification and deletions in 11% (9/82) and 13% (11/82) of TNBCs, respectively. In contrast, 1% (2/209) of ER-positive BCs were found to have AKT-3 amplifications and deletions. A higher prevalence of AKT-3 copy number gains was observed in TNBC [26% (21/82)] than in ER-positive BC [9% (19/209)]. AKT-3 amplification together with Akt-3 protein expression was negatively associated with recurrence-free survival in TNBC. Furthermore, a negative association between high AKT-3 copy number and recurrence-free survival was observed. CONCLUSION: AKT-3 amplification could represent a potentially relevant oncogenic event in a subset of TNBCs that may, in turn, select cells sensitive to Akt-3 inhibitors.

Comparative antiproliferative effects of iniparib and olaparib on a panel of triple-negative and non-triple-negative breast cancer cell lines.

PARP inhibitors, both as monotherapy and in combination with cytotoxic drugs, are currently undergoing clinical trials in several different cancer types. In this investigation, we compared the antiproliferative activity of two PARP/putative PARP inhibitors, i.e., olaparib and iniparib, in a panel of 14 breast cancer cell lines (seven tripe-negative and seven non-triple-negative). In almost all cell lines investigated, olaparib was a more potent inhibitor of cell growth than iniparib. Inhibition by both drugs was cell line-dependent and independent of the molecular subtype status of the cells, i.e., whether cells were triple-negative or non-triple negative. Although the primary target of PARP inhibitors is PARP1, no significant association was found between baseline levels of PARP1 activity and inhibition with either agent. Similarly, no significant correlation was evident between sensitivity and levels of CDK1, BRCA1 or miR-182. Combined addition of olaparib and either the CDK1 inhibitor, RO-3306 or a pan HER inhibitor (neratinib, afatinib) resulted in superior growth inhibition to that obtained with olaparib alone. We conclude that olaparib, in contrast to iniparib, is a strong inhibitor of breast cancer cell growth and may have efficacy in breast cancer irrespective of its molecular subtype, i.e., whether HER2-positive, estrogen receptor (ER)-positive or triple-negative. Olaparib, in combination with a selective CDK1 inhibitor or a pan HER inhibitor, is a potential new approach for treating breast cancer.

The ADAMs family of proteases: new biomarkers and therapeutic targets for cancer?

The ADAMs are transmembrane proteins implicated in proteolysis and cell adhesion. Forty gene members of the family have been identified, of which 21 are believed to be functional in humans. As proteases, their main substrates are the ectodomains of other transmembrane proteins. These substrates include precursor forms of growth factors, cytokines, growth factor receptors, cytokine receptors and several different types of adhesion molecules. Although altered expression of specific ADAMs has been implicated in different diseases, their best-documented role is in cancer formation and progression. ADAMs shown to play a role in cancer include ADAM9, ADAM10, ADAM12, ADAM15 and ADAM17. Two of the ADAMs, i.e., ADAM10 and 17 appear to promote cancer progression by releasing HER/EGFR ligands. The released ligands activate HER/EGFR signalling that culminates in increased cell proliferation, migration and survival. Consistent with a causative role in cancer, several ADAMs are emerging as potential cancer biomarkers for aiding cancer diagnosis and predicting patient outcome. Furthermore, a number of selective ADAM inhibitors, especially against ADAM10 and ADAM17, have been shown to have anti-cancer effects. At least one of these inhibitors is now undergoing clinical trials in patients with breast cancer.

Levels of specific glycans significantly distinguish lymph node-positive from lymph node-negative breast cancer patients.

One of the most urgent requirements in breast cancer is the development of a blood-based test for early detection and prognosis. Previously published results found a significant difference between specific glycan levels in patients with advanced breast cancer and healthy controls. The aim of this investigation was to address a more clinically relevant problem, i.e., whether the measurement of specific glycans could identify women with aggressive disease at an early stage. In order to reduce potential bias in this study, blood samples from patients were collected, stored and analyzed in a similar manner. Agalactosyl biantennary glycans (FA2) and glycans containing the sialyl Lewis x epitope (A3F1G1 and A2F1G1) were measured using high throughput normal-phase high-performance liquid chromatography in combination with exoglycosidase digestions in sera from 52 patients with early breast cancer (21 with lymph node-negative and 20 with lymph node-positive disease) and 134 women with benign breast disease. The combined levels of the glycans were significantly higher in patients with lymph node metastases compared to women without these metastases. Lymph node status is the single most important determinant of survival in early stage breast cancer. As high levels of these glycans were associated with nodal metastases, their measurement may provide a new non-invasive approach to determining prognosis in women with newly diagnosed breast cancer.