Harris Pratsinis | National Centre of Scientific Research "DEMOKRITOS" (original) (raw)

Uploads

Papers by Harris Pratsinis

Bioorganic & medicinal chemistry letters, 2005

A series of novel xanthenone aminoderivatives and their pyrazole-fused counterparts possessing st... more A series of novel xanthenone aminoderivatives and their pyrazole-fused counterparts possessing structural analogy to the potent anticancer agent 9-methoxypyrazoloacridine (PZA) reported. These compounds exhibited an interesting cytotoxic activity against a panel of cell lines. Most noticeably, they retain activity against the multidrug resistant MES-SA/Dx5 subline, showing resistant factors close to 1.

Journal of Cancer Research and Clinical Oncology, 2010

Seminars in Cancer Biology, 2019

Transforming Growth Factor-β (TGF-β) is the prototype of a growth factor family playing central r... more Transforming Growth Factor-β (TGF-β) is the prototype of a growth factor family playing central roles in a wide variety of functions both at the tissue and the organismal levels, ranging from the regulation of cell proliferation, and the enhancement of extracellular matrix accumulation to immunosuppression and a dual role in cancer development. Here, we present a brief description of TGF-β in terms of structural and functional aspects, including the major signal transduction pathways activated by it. The role of TGF-β as an inducer of cellular senescence in normal, malignant and stem cells is documented, as well as, its ability to induce or reinforce senescence when acting in an autocrine or paracrine fashion, as part of the senescence-associated secretory phenotype. The interplay of TGF-β with the two major intracellular protein degradation systems, i.e. autophagy and the ubiquitin-proteasome system, is also discussed, given their associations with senescence and age-related pathol...

Advanced Drug Delivery Reviews, 2018

Osteoarthritis and Cartilage, 2016

Antioxidants

Skin health is heavily affected by ultraviolet irradiation from the sun. In addition, senile skin... more Skin health is heavily affected by ultraviolet irradiation from the sun. In addition, senile skin is characterized by major changes in the collagen, elastin and in the hyaluronan content. Natural products (NPs) have been shown to delay cellular senescence or in vivo aging by regulating age-related signaling pathways. Moreover, NPs are a preferable source of photoprotective agents and have been proven to be useful against the undesirable skin hyperpigmentation. Greek flora harvests great plant diversity with approximately 6000 plant species, as it has a wealth of NPs. Here, we report an extensive screening among hundreds of plant species. More than 440 plant species and subspecies were selected and evaluated. The extracts were screened for their antioxidant and anti-melanogenic properties, while the most promising were further subjected to various in vitro and cell-based assays related to skin aging. In parallel, their chemical profile was analyzed with High-Performance Thin-Layer Ch...

Cancers

Down-regulation of the small leucine-rich proteoglycan decorin in the stroma is considered a poor... more Down-regulation of the small leucine-rich proteoglycan decorin in the stroma is considered a poor prognostic factor for breast cancer progression. Ionizing radiation, an established treatment for breast cancer, provokes the premature senescence of the adjacent to the tumor stromal fibroblasts. Here, we showed that senescent human breast stromal fibroblasts are characterized by the down-regulation of decorin at the mRNA and protein level, as well as by its decreased deposition in the pericellular extracellular matrix in vitro. Senescence-associated decorin down-regulation is a long-lasting process rather than an immediate response to γ-irradiation. Growth factors were demonstrated to participate in an autocrine manner in decorin down-regulation, with bFGF and VEGF being the critical mediators of the phenomenon. Autophagy inhibition by chloroquine reduced decorin mRNA levels, while autophagy activation using the mTOR inhibitor rapamycin enhanced decorin transcription. Interestingly, t...

International Journal of Molecular Sciences

Recent studies have linked the activity of ER aminopeptidase 2 (ERAP2) to increased efficacy of i... more Recent studies have linked the activity of ER aminopeptidase 2 (ERAP2) to increased efficacy of immune-checkpoint inhibitor cancer immunotherapy, suggesting that pharmacological inhibition of ERAP2 could have important therapeutic implications. To explore the effects of ERAP2 inhibition on the immunopeptidome of cancer cells, we treated MOLT-4 T lymphoblast leukemia cells with a recently developed selective ERAP2 inhibitor, isolated Major Histocompatibility class I molecules (MHCI), and sequenced bound peptides by liquid chromatography tandem mass spectrometry. Inhibitor treatment induced significant shifts on the immunopeptidome so that more than 20% of detected peptides were either novel or significantly upregulated. Most of the inhibitor-induced peptides were 9mers and had sequence motifs and predicted affinity consistent with being optimal ligands for at least one of the MHCI alleles carried by MOLT-4 cells. Such inhibitor-induced peptides could serve as triggers for novel cytot...

Biomimetics

Targeted delivery of chemotherapeutics in order to overcome side effects and enhance chemosensiti... more Targeted delivery of chemotherapeutics in order to overcome side effects and enhance chemosensitivity remains a major issue in cancer research. In this context, biocompatible oil-in-water (O/W) microemulsions were developed as matrices for the encapsulation of DPS-2 a benzothiophene analogue, exhibiting high cytotoxicity in various cancer cell lines, among them the MW 164 skin melanoma and Caco-2 human epithelial colorectal adenocarcinoma cell lines. The microemulsion delivery system was structurally characterized by dynamic light scattering (DLS) and electron paramagnetic resonance (EPR) spectroscopy. The effective release of a lipophilic encapsulated compound was evaluated via confocal microscopy. The cytotoxic effect, in the presence and absence of DPS-2, was examined through the thiazolyl blue tetrazolium bromide (MTT) cell proliferation assay. When encapsulated, DPS-2 was as cytotoxic as when dissolved in dimethyl sulfoxide (DMSO). Hence, the oil cores of O/W microemulsions wer...

Planta medica, Jan 24, 2016

The Cretan diet, as the basis of the Mediterranean diet, has provided traditional remedies for th... more The Cretan diet, as the basis of the Mediterranean diet, has provided traditional remedies for the general well being of people through the long-established consumption of cooked wild greens and vegetables. The intake of the water decoctions of Cichorium spinosum and Cichorium intybus in the context of the daily dietary regime in Greece has been long associated with "liver detoxifying" properties. In the current study, we performed an in-depth investigation of the water decoctions traditionally prepared from C. spinosum and C. intybus through qualitative UHPLC-HRMS profiling and direct quantification of cichoric and caftaric acid as major antioxidant components of the decoction. In addition, we developed a one-step countercurrent chromatography method for the isolation of the two phenolic acids, along with a sulfoconjugate sesquiterpene lactone present only in the Cretan C. spinosum. All water decoctions were found not to be cytotoxic in human fibroblasts, whereas they all...

Wound Repair and Regeneration, 2004

Wound Repair and Regeneration, 2013

Senescent cells observed in the area of chronic wounds have been proposed to affect wound healing... more Senescent cells observed in the area of chronic wounds have been proposed to affect wound healing. Therapeutic approaches against chronic wounds include, among others, the local application of living cell constructs (LCCs), containing fibroblasts and/or keratinocytes. Accordingly, the aim of the present work was to examine the effects of factors secreted by early passage neonatal fibroblasts and LCCs--in the form of a conditioned medium (CM)--on senescent adult dermal fibroblasts regarding functions related to the healing process, i.e., cell proliferation, alpha-smooth muscle actin and metalloproteinase expression, and collagen synthesis. Target cells were fibroblasts senescent either due to subsequent divisions (replicative senescence) or due to an exogenous stress (stress-induced premature senescence). No effect on the proliferation of senescent fibroblasts was observed, as expected. All CMs were found to inhibit overall collagen synthesis both in early passage and in senescent fibroblasts. The LCC-derived CM was found to be more potent than fibroblast-derived CMs and, furthermore, to inhibit alpha-smooth muscle actin expression. In conclusion, these results may indicate anti-contractile and anti-fibrotic activities of factor(s) secreted by neonatal skin fibroblasts, and more intensely by LCCs on adult donor-derived fibroblasts. These activities seem to persist during senescence of the target cells.

Planta Medica, 2003

Bioassay-guided fractionation of the neutral extract of the bark of Sarcomelicope megistophylla r... more Bioassay-guided fractionation of the neutral extract of the bark of Sarcomelicope megistophylla resulted in the isolation of the new nor-neolignan sarcomeginal ( 1), together with the known ailanthoidol ( 2) and (+/-)-seco-isolariciresinol ( 3). The structure of 1 was determined by spectroscopic means. Estrogenic activity of the isolated compounds was tested using estrogen receptor-positive MCF7 and estrogen receptor-negative MDA-MB-231 human mammary adenocarcinoma cell lines. Compound 3 displayed significant estrogenic activity.

Laboratory Investigation, 2005