Hector Katifelis

Dr. Hector Katifelis

National and Kapodistrian University of Athens, Athens, Attikí, Greece
orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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27 June 2024 in Molecules
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Journal Article
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CMChrysa Marasli
Chrysa Marasli
HKHector Katifelis
Hector Katifelis
Maria GazouliMaria Gazouli
Maria Gazouli
NLNefeli Lagopati
Nefeli Lagopati
Rehabilitation of fully or partially edentulous patients with dental implants represents one of the most frequently used surgical procedures. The work of Branemark, who observed that a piece of titanium embedded in rabbit bone became firmly attached and difficult to remove, introduced the concept of osseointegration and revolutionized modern dentistry. Since then, an ever-growing need for improved implant materials towards enhanced material–tissue integration has emerged. There is a strong belief that nanoscale materials will produce a superior generation of implants with high efficiency, low cost, and high volume. The aim of this review is to explore the contribution of nanomaterials in implantology. A variety of nanomaterials have been proposed as potential candidates for implant surface customization. They can have inherent antibacterial properties, provide enhanced conditions for osseointegration, or act as reservoirs for biomolecules and drugs. Titania nanotubes alone or in combination with biological agents or drugs are used for enhanced tissue integration in dental implants. Regarding immunomodulation and in order to avoid implant rejection, titania nanotubes, graphene, and biopolymers have successfully been utilized, sometimes loaded with anti-inflammatory agents and extracellular vesicles. Peri-implantitis prevention can be achieved through the inherent antibacterial properties of metal nanoparticles and chitosan or hybrid coatings bearing antibiotic substances. For improved corrosion resistance various materials have been explored. However, even though these modifications have shown promising results, future research is necessary to assess their clinical behavior in humans and proceed to widespread commercialization.

17 March 2022 in Cancers
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Journal Article
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HKHector Katifelis
Hector Katifelis
MNMaria-Paraskevi Nikou
Maria-Paraskevi Nikou
IMIuliia Mukha
Iuliia Mukha
NVNadiia Vitiuk
Nadiia Vitiuk
NLNefeli Lagopati
Nefeli Lagopati
Maria GazouliMaria Gazouli
Maria Gazouli
Apoptosis induction is a common therapeutic approach. However, many cancer cells are resistant to apoptotic death and alternative cell death pathways including pyroptosis and necroptosis need to be triggered. At the same time, danger signals that include HMGB1 and HSP70 can be secreted/released by damaged cancer cells that boost antitumor immunity. We studied the cytotoxic effects of AgAu NPs, Ag NPs and Au NPs with regard to the programmed cell death (apoptosis, necroptosis, pyroptosis) and the secretion/release of HSP70 and HMGB1. Cancer cell lines were incubated with 30, 40 and 50 μg/mL of AgAu NPs, Ag NPs and Au NPs. Cytotoxicity was estimated using the MTS assay, and mRNA fold change of CASP1, CASP3, BCL-2, ZPB1, HMGB1, HSP70, CXCL8, CSF1, CCL20, NLRP3, IL-1β and IL-18 was used to investigate the associated programmed cell death. Extracellular levels of HMGB1 and IL-1β were investigated using the ELISA technique. The nanoparticles showed a dose dependent toxicity. Pyroptosis was triggered for LNCaP and MDA-MB-231 cells, and necroptosis for MDA-MB-231 cells. HCT116 cells experience apoptotic death and show increased levels of extracellular HMGB1. Our results suggest that in a manner dependent of the cellular microenvironment, AgAu NPs trigger mixed programmed cell death in P53 deficient MDA-MB-231 cells, while they also trigger IL-1β release in MDA-MB-231 and LNCaP cells and release of HMGB1 in HCT116 cells.

1 August 2020 in International Journal of Nanomedicine
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Journal Article
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HKHector Katifelis
Hector Katifelis
IMIuliia Mukha
Iuliia Mukha
PGPenelope Greece
Penelope Greece
NVNadiia Vityuk
Nadiia Vityuk
CTCharalampos Tsoukalas
Charalampos Tsoukalas
Maria GazouliMaria Gazouli
Maria Gazouli
Purpose: To evaluate the antitumor efficacy of Ag3Au1Trp1:2NPs in a SCID mouse cancer model, with respect to their effect on tumor growth, on tumor’s metastatic potential and the underlying molecular mechanism. Subjects and Methods: Ag3Au1Trp1:2NPs were radiolabeled with Gallium-68 and the biodistribution was studied in Swiss mice without tumors and in SCID mice bearing tumors. SCID mice received intratumoral Ag3Au1Trp1:2NPs and tumor size was measured using calipers. Lung and liver tissues were extracted and studied microscopically for the detection of any metastatic sites. Changes in the Caspase-3 and TNF-related apoptosis-inducing ligand (TRAIL) were also investigated using real-time PCR and Western blot techniques, respectively. Results: In the 4T1 tumor-bearing SCID mice, Ag3Au1Trp1:2NPs showed quick passive accumulation at tumor sites at 30 mins post-injection. Mice that received the highest dose of NPs (5.6mg/mL) demonstrated a 1.9-fold lower tumor volume compared to that of the control group at 11 days post-injection, while mice that did not receive NPs showed metastatic sites in liver and lung. Extracted tumor tissue of treated mice revealed increased Casp-3 mRNA levels as well as elevated TRAIL protein levels. Conclusion: Based on our results, Ag3Au1Trp1:2NPs express anti-tumor and anti-metastatic effects in vivo. Ag3Au1Trp1:2NPs also reach tumor site via the enhancement and retention effect which results in the apoptotic death of cancerous cells selectively via the extrinsic TRAIL-dependent pathway.

1 March 2024 in Biomimetics
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TVTheodoros-Filippos Valamvanos
Theodoros-Filippos Valamvanos
XDXanthippi Dereka
Xanthippi Dereka
HKHector Katifelis
Hector Katifelis
Maria GazouliMaria Gazouli
Maria Gazouli
NLNefeli Lagopati
Nefeli Lagopati
The rehabilitation of alveolar bone defects of moderate to severe size is often challenging. Currently, the therapeutic approaches used include, among others, the guided bone regeneration technique combined with various bone grafts. Although these techniques are widely applied, several limitations and complications have been reported such as morbidity, suboptimal graft/membrane resorption rate, low structural integrity, and dimensional stability. Thus, the development of biomimetic scaffolds with tailor-made characteristics that can modulate cell and tissue interaction may be a promising tool. This article presents a critical consideration in scaffold’s design and development while also providing information on various fabrication methods of these nanosystems. Their utilization as delivery systems will also be mentioned.

8 May 2024 in Biomedicines
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TSTheodoros A Sidiropoulos
Theodoros A Sidiropoulos
Nikolas DovrolisNikolas Dovrolis
Nikolas Dovrolis
HKHector Katifelis
Hector Katifelis
Nikolaos V. MichalopoulosNikolaos V. Michalopoulos
Nikolaos V. Michalopoulos
PKPanagiotis Kokoropoulos
Panagiotis Kokoropoulos
Maria GazouliMaria Gazouli
Maria Gazouli
Pancreatic cancer (PC) ranks as the seventh leading cause of cancer-related deaths, with approximately 500,000 new cases reported in 2020. Existing strategies for early PC detection primarily target individuals at high risk of developing the disease. Nevertheless, there is a pressing need to identify innovative clinical approaches and personalized treatments for effective PC management. This study aimed to explore the dysbiosis signature of the fecal microbiota in PC and potential distinctions between its Intraductal papillary mucinous neoplasm (IPMN) and pancreatic ductal adenocarcinoma (PDAC) phenotypes, which could carry diagnostic significance. The study enrolled 33 participants, including 22 diagnosed with PDAC, 11 with IPMN, and 24 healthy controls. Fecal samples were collected and subjected to microbial diversity analysis across various taxonomic levels. The findings revealed elevated abundances of Firmicutes and Proteobacteria in PC patients, whereas healthy controls exhibited higher proportions of Bacteroidota. Both LEfSe and Random Forest analyses indicated the microbiome’s potential to effectively distinguish between PC and healthy control samples but fell short of differentiating between IPMN and PDAC samples. These results contribute to the current understanding of this challenging cancer type and highlight the applications of microbiome research. In essence, the study provides clear evidence of the gut microbiome’s capability to serve as a biomarker for PC detection, emphasizing the steps required for further differentiation among its diverse phenotypes.

4 April 2022 in Materials
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Journal Article
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VCVarvara Chrysostomou
Varvara Chrysostomou
HKHector Katifelis
Hector Katifelis
Maria GazouliMaria Gazouli
Maria Gazouli
Konstantinos DimasKonstantinos Dimas
Konstantinos Dimas
Costas DemetzosCostas Demetzos
Costas Demetzos
Stergios PispasStergios Pispas
Stergios Pispas
Research on the improvement and fabrication of polymeric systems as non-viral gene delivery carriers is required for their implementation in gene therapy. Random copolymers have not been extensively utilized for these purposes. In this regard, double hydrophilic poly[(2-(dimethylamino) ethyl methacrylate)-co-(oligo(ethylene glycol) methyl ether methacrylate] [P(DMAEMA-co-OEGMA)] random copolymers were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The copolymers were further modified by quaternization of DMAEMA tertiary amine, producing the cationic P(QDMAEMA-co-OEGMA) derivatives. Fluorescence and ultraviolet–visible (UV–vis) spectroscopy revealed the efficient interaction of copolymers aggregates with linear DNAs of different lengths, forming polyplexes, with the quaternized copolymer aggregates exhibiting stronger binding affinity. Light scattering techniques evidenced the formation of polyplexes whose size, molar mass, and surface charge strongly depend on the N/P ratio (nitrogen (N) of the amine group of DMAEMA/QDMAEMA over phosphate (P) groups of DNA), DNA length, and length of the OEGMA chain. Polyplexes presented colloidal stability under physiological ionic strength as shown by dynamic light scattering. In vitro cytotoxicity of the empty nanocarriers was evaluated on HEK293 as a control cell line. P(DMAEMA-co-OEGMA) copolymer aggregates were further assessed for their biocompatibility on 4T1, MDA-MB-231, MCF-7, and T47D breast cancer cell lines presenting high cell viability rates.