Athanasios Armakolas

Preferential expression of IGF-1Ec (MGF) transcript in cancerous tissues of human prostate: evidence for a novel and autonomous growth factor activity of MGF E peptide in human prostate cancer cells.

By alternative splicing the IGF‐1 gene produces several different transcripts, including IGF‐1Ec (MGF). The latter has been mainly associated with muscle regeneration processes.

Detection of the circulating tumor cells in cancer patients

As the presence of tumor cells circulating in the blood is associated with systemic disease and shortened survival, the establishment of a method to detect circulating tumor cells (CTCs) is of critical importance for a more concise staging and follow-up of cancer patients. Recently, the most robust strategies for the determination of CTCs are the PCR-based methods and the CellSearch® system that exploits the immunofluorescent characterization and isolation of cancer cells. Herein, we analyzed the experimental strategies used for determining CTCs with respect to accuracy, sensitivity and reproducibility in cancers of the breast, colon, prostate and melanoma.

Novel Tools for Prostate Cancer Prognosis, Diagnosis, and Follow-Up

Prostate-specific antigen (PSA) is the main diagnostic tool when it comes to prostate cancer but it possesses serious limitations. Therefore, there is an urgent need for more sensitive and specific biomarkers for prostate cancer prognosis and patient follow-up. Recent advances led to the discovery of many novel diagnostic/prognostic techniques and provided us with many worthwhile candidates. This paper briefly reviews the most promising biomarkers with respect to their implementation in screening, early detection, diagnostic confirmation, prognosis, and prediction of therapeutic response or monitoring disease and recurrence; and their use as possible therapeutic targets. This review also examines the possible future directions in the field of prostate cancer marker research.

Methods of detection of circulating melanoma cells: A comparative overview

Disease dissemination is the major cause of melanoma-related death. A crucial step in the metastatic process is the intravascular invasion and circulation of melanoma cells in the bloodstream with subsequent development of distant micrometastases that is initially clinically undetectable and will eventually progress into clinically apparent metastasis. Therefore, the use of molecular methods to detect circulating melanoma cells may be of value in risk stratification and clinical management of such patients. Herein, we review the currently applied techniques for the detection, isolation, enrichment and further characterization of circulating melanoma cells from peripheral blood samples in melanoma patients. Furthermore, we provide a brief overview of the various molecular markers currently being evaluated as prognostic indicators of melanoma progression.

Evidence for the Possible Biological Significance of the igf-1 Gene Alternative Splicing in Prostate Cancer.

Insulin-like growth factor-I (IGF-I) has been implicated in the pathogenesis of prostate cancer (PCa), since it plays a key role in cell proliferation, differentiation, and apoptosis. The IGF-I actions are mediated mainly via its binding to the type I IGF receptor (IGF-IR), however IGF-I signaling via insulin receptor (IR) and hybrid IGF-I/IR is also evident. Different IGF-I mRNA splice variants, namely IGF-IEa, IGF-IEb, and IGF-IEc, are expressed in human cells and tissues. These transcripts encode several IGF-I precursor proteins which contain the same bioactive product (mature IGF-I), however, they differ by the length of their signal peptides on the amino-terminal end and the structure of the extension peptides (E-peptides) on the carboxy-terminal end. There is an increasing interest in the possible different role of the IGF-I transcripts and their respective non-(mature)IGF-I products in the regulation of distinct biological activities. Moreover, there is strong evidence of a differential expression profile of the IGF-I splice variants in normal versus PCa tissues and PCa cells, implying that the expression pattern of the various IGF-I transcripts and their respective protein products may possess different functions in cancer biology. Herein, the evidence that the IGF-IEc transcript regulates PCa growth via Ec peptide specific and IGF-IR/IR-independent signaling is discussed.

The role of Ki-67 in the proliferation and prognosis of breast cancer molecular classification subtypes.

The Ki-67 antigen was identified in the early steps of polymerase I-dependent ribosomal RNA synthesis. Although it seems that this protein has an important function in cell division, its exact role is still unclear and there is little published work on its overall function. The aim of the present study was to evaluate the contribution of the level of Ki-67 with respect to tumor recurrence in molecularly classified groups of breast cancer patients. Ki-67 was divided into the percentage levels up to and including 20% and over 20%. Immunohistochemistry and fluorescence in-situ hybridization are described for the results of estrogen receptor, progesterone receptor, c-erb-B2, and Ki-67 biomarkers. Formaldehyde-fixed breast samples were paraffin wax embedded and processed for paraffin sections. The protocol of the present study started in 1995 and finished in 2010. Nine hundred and sixteen patients with breast cancer were examined: 291 were grouped as luminal A, 228 as luminal B, 221 as the Her-2 subtype, and 107 as basal cell (triple negative). Follow-up ranged from 3 to 15 years following diagnosis. It was found that in luminal A patients, only one had a Ki-67 level higher than 20%. In luminal B, the Ki-67 was higher than 20% in 51.16% of the patients and recurrence occurred in 23.68%. In the Her-2 subtype, the Ki-67 level was more than 20% in 48.63%. In basal cell triple-negative patients, Ki-67 was more than 20% in 63.86%. The data presented here indicate that the level of Ki-67 may be considered one of the valuable biomarkers in breast cancer patients with respect to process and recurrence.

Autophagy: a target for therapeutic interventions in myocardial pathophysiology

Background: Autophagy is a major degradative and highly conserved process in eukaryotic cells that is activated by stress signals. This self-cannibalisation is activated as a response to changing environmental conditions, cellular remodelling during development and differentiation, and maintenance of homeostasis. Objective: To review autophagy regarding its process, molecular mechanisms and regulation in mammalian cells, and its role in myocardial pathophysiology. Results/conclusion: Autophagy is a multistep process regulated by diverse, intracellular and/or extracellular signalling complexes and pathways. In the heart, normally, autophagy occurs at low basal levels, where it represents a homeostatic mechanism for the maintenance of cardiac function and morphology. However, in the diseased heart the functional role of the enhanced autophagy is unclear and studies have yielded conflicting results. Recently, it was shown that during myocardial ischemia autophagy promotes survival by maintaining energy homeostasis. Also, rapamycin was demonstrated to prevent cardiac hypertrophy. In heart failure, upregulation of autophagy acts as an adaptive response that protects cells from hemodynamic stress. In addition, sirolimus-eluting stents have been shown to lower re-stenosis rates in patients with coronary artery disease after angioplasty. Thus, this mechanism can become a major target for therapeutic intervention in heart pathophysiology.

Oncogenic Role of the Ec Peptide of the IGF-1Ec Isoform in Prostate Cancer

IGF-1 is one of the key molecules in cancer biology; however, little is known about the role of the preferential expression of the premature IGF-1 isoforms in prostate cancer. We have examined the role of the cleaved COO− terminal peptide (PEc) of the third IGF-1 isoform, IGF-1Ec, in prostate cancer. Our evidence suggests that endogenously produced PEc induces cellular proliferation in the human prostate cancer cells (PC-3) in vitro and in vivo, by activating the ERK1/2 pathway in an autocrine/paracrine manner. PEc overexpressing cells and tumors presented evidence of epithelial to mesenchymal transition, whereas the orthotopic injection of PEc-overexpressing, normal prostate epithelium cells (HPrEC) in SCID mice was associated with increased metastatic rate. In humans, the IGF-1Ec expression was detected in prostate cancer biopsies, where its expression correlates with tumor stage. Our data describes the action of PEc in prostate cancer biology and defines its potential role in tumor growth, progression and metastasis.

Subdivision of molecularly-classified groups by new gene signatures in breast cancer patients.

Gene expression patterns as well as gene interactions are under investigation for their involvement in tumour heterogeneity. The molecular classification of breast cancer based on hormone receptor expression, grade and HER2 receptor levels, is indicative but not adequate enough to complete the prognostic data. The objectives of this study were to validate the prognostic value of 19 genes, solely, and as parts of classifiers (sets of genes), in breast cancer patients and to determine whether the expression of these genes and classifiers is correlated with breast cancer molecular classification. Gene expression was examined in the blood of 88 breast cancer patients and 50 healthy controls using multiplex quantitative real-time PCR. Patients with a second primary malignancy showed a statistically significant difference when compared with: i) patients with a single breast cancer, for an 8-gene classifier (p<0.02); and ii) healthy individuals (classifier FBX033, FLJ339115) (p<0.01), with respect to gene expression. The classifier ENY2, USP38 was associated with the development of primary breast cancer. A newly established classifier (ENY2, USP38, RPS7, Osbpl-1 and ETF1) indicated a statistically significant association with HER2 subtype patients, compared to patients with a different molecular classification (p<0.04). The gene FLJ33915 was differentially expressed in a subgroup of HER2-positive patients with infiltrated axillary lymph nodes (p<0.028). We validated the prognostic value of 4 classifiers for primary and second primary malignancy. Evidence of a classifier predicting the HER2 subtype and the gene FLJ33915 which subdivides HER2 subtype patients is also presented.

Possible role of the Ec peptide of IGF‑1Ec in cartilage repair.

The Ec peptide (PEc) of insulin-like growth factor 1 Ec (IGF-1Ec) induces human mesenchymal stem cell (hMSC) mobilization and activates extracellular signal-regulated kinase 1/2 (ERK 1/2) in various cells. The aim of the present study was to examine the effects of PEc on the mobilization and differentiation of hMSCs, as well as the possibility of its implementation in combination with transforming growth factor β1 (TGF-β1) for cartilage repair. The effects of the exogenous administration of PEc and TGF-β1, alone and in combination, on hMSCs were assessed using a trypan blue assay, reverse transcription-quantitative polymerase chain reaction, western blot analysis, Alcian blue staining, wound healing assays and migration/invasion assays. It was determined that PEc is involved in the differentiation process of hMSCs towards hyaline cartilage. Treatment of hMSCs with either PEc, TGF-β1 or both, demonstrated comparable cartilage matrix deposition. Furthermore, treatment with PEc in combination with TGF-β1 was associated with a significant increase in hMSC mobilization when compared with treatment with TGF-β1 or PEc alone (P<0.05). Thus, PEc appears to facilitate in vitro hMSC mobilization and differentiation towards chondrocytes, enhancing the role of TGF-β1.