Normal Human Skin Fibroblast Cells Research Articles

Evaluation of cytotoxic and genotoxic potential of avobenzone and octocrylene on human skin fibroblast cells

We investigated the cytotoxic and genotoxic effects of the organic UVA filter avobenzone (AVB), and the UVB filter octocrylene (OCT), found alone or in combination in different sunscreen formulations, on normal human skin fibroblast cells (CCD-1118Sk). To achieve this purpose, we used XTT viability assay, single cell gel electrophoresis (comet) assay and reactive oxygen species (ROS) assay. For cytotoxicity, CCD-1118Sk cells were exposed to various concentrations of AVB (32–800 µM), and OCT (130–6500 μM). The IC50 values were 100.2 and 1390.95 µM for AVB and OCT, respectively. IC12.5, IC25 and IC50 concentrations were chosen for genotoxicity testing. The comet assay revealed DNA damage at the two highest concentrations of AVB and all OCT concentrations. The rate of DNA damage was significantly higher than in the control groups. Co-treatment with AVB and OCT increased the level of DNA damage and intracellular oxidative stress compared with AVB and OCT treatment alone. Finally, our study showed that the UVA filter AVB, with the UVB filter OCT, may induce cytotoxic and genotoxic effects on human skin fibroblast cells. Highlights Avobenzone and octocrylene are UV filters used in sunscreen products. Healthy human skin fibroblast cell line CCD-1118Sk was used for cytotoxic and genotoxic assays. Cotreatment with avobenzone and octocrylene caused more severe DNA damage than their treatment alone. Our findings will contribute to the limited number of cytotoxicity and genotoxicity studies and lead to more detailed studies on the use of these two chemicals.

Optimization and characterization of antileukemic l-asparaginase produced by Fusarium solani endophyte

l-asparaginase is an antileukemic enzyme that hydrolyzes l-asparagine into l-aspartic acid and ammonia, causing cell starvation and apoptosis in susceptible leukemic cell populations. Currently, l-asparaginase obtained from bacterial sources is constrained by several issues, including lesser productivity, stability, selectivity, and higher toxicity. The goal of this study is to provide fungal l-asparaginase with in-vitro effectiveness towards different human carcinomas. l-asparaginase from endophytic Fusarium solani (Gene Bank accession number MW209717) isolated from the roots of the medicinal plant Hedera helix L. was characterized and optimized experimentally for maximum l-asparaginase production in addition to evaluating its subsequent cytotoxicity towards acute monocytic leukemia and human skin fibroblast cell lines. The enzyme production was maximized using potato dextrose media (15.44 IU/ml/hr) at the 5th and 6th days of fermentation with incubation temperature 30 °C, 3% asparagine, 150–180 rpm agitation rate and a 250 ml flask. Enzyme characterization studies revealed that the enzyme maintained its thermal stability with temperatures up to 60 °C. However, its optimal activity was achieved at 35 °C. On measuring the enzymatic activity at various temperatures and different pH, maximum enzyme activity was recorded at 40 °C and pH 8 using 0.1 M asparagine concentration. Results also revealed promising cytotoxic activity against acute monocytic leukemia with IC50 = 3.66 µg/ml and low cytotoxicity against tested normal human skin fibroblast cell line which suggested that it might have selective toxicity, and consequently it could be used as a less toxic alternative to the current formulations.

Green Synthesis of Silver and Titanium Oxide Nanoparticles Using Tea and Eggshell Wastes, Their Characterization, and Biocompatibility Evaluation

Using biodegradable wastes represents a viable alternative to creating a sustainable economy that benefits all humans. The present study aimed to use daily used waste products, tea (TE) and eggshell (ES) wastes, to synthesize silver (AgNPs) and titanium oxide (TiO2NPs) nanoparticles, respectively. Firstly, the green-synthesized nanoparticles were characterized using an ultraviolet-visible spectrophotometer (UV-VIS), Scanning (SEM), transmission electron microscope (TEM), Dynamic light scattering (DLS), zeta potential analysis, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. Then, followed by their cytotoxic assessment against normal human skin fibroblast (HSF) cells using sulforhodamine B (SRB) assay, AgNPs_TE (300 and 470 nm) and TiO2NPs_ESE (320 nm) formation was confirmed using UV-vis spectra. SEM and XRD showed their crystalline shape. TEM images determined the nano-size of AgNPs_TE (25 nm) and TiO2NPs_ESE (120 nm), which appeared smaller in comparison with DLS analysis (299.8 and 742.9 nm), with zeta potentials of −20.5 mV and −12.6 mV, respectively. There was a great difference in both NPs’ sizes using TEM and DLS measurements because DLS is known to be more sensitive to larger particles due to their light scattering. FTIR detected the functional groups found in TE and ESE that were responsible for the synthesis, capping, and stabilization of the synthesized AgNPs and TiO2NPs. The SRB assay reveals the safety of TiO2NPs on normal HSF cells with an IC50 > 100, while AgNPs have a high cytotoxic effect with an IC50 = 54.99 μg/mL.

Sustainable Eco-Friendly Synthesis of Zinc Oxide Nanoparticles Using Banana Peel and Date Seed Extracts, Characterization, and Cytotoxicity Evaluation

This study describes the use of banana peel (BPEs) and date seed extracts (DSEs) as waste products in the sustainable and eco-friendly biological synthesis of zinc oxide nanoparticles (ZnONPs). ZnONPs_BPE and ZnONPs_DSE were characterized using an ultraviolet-visible spectrophotometer (UV-VIS), Scanning (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), dynamic light scattering (DLS), zeta potential analysis, and Fourier transform infrared (FTIR) spectroscopy. Moreover, the biocompatibility of ZnONPs was analyzed against the normal human skin fibroblast (HSF) cell line. Peaks of UV spectra were 300 nm and 400 nm for ZnONPs-BPE and for ZnONP _DSE, respectively, confirming the ZnONPs’ formation. XRD revealed their hexagonal structure. SEM showed the nanocrystals of ZnONPs_BPE, which are interlinked to one another in a uniform shape, while ZnONPs_DSE appear as large and small chunky crystals. The mean size of ZnONPs_BPE and ZnONPs_DSE was 50 nm and 62 nm using TEM, respectively. On the contrary, their mean size was bigger using DLS with the zeta potential of ZnONPs_BPE = −12.7 mV and ZnONPs_DSE = −5.69 mV. The FTIR analysis demonstrated the presence of carboxyl, hydroxyl, and C–H of cellulose, hemicelluloses, and lignin polymers on ZnONPs surfaces that act as reducing, capping, and stabilizing agents. ZnONPs_BPE (IC50 > 100) have lower cytotoxic effects on HSF cells than ZnONPs_DSE (IC50 = 29.34 μg/mL). The present study indicates the successful synthesis of ZnONPs using agro-wastes that could help in waste management and recycling. Furthermore, ZnONPs_BPE is safe to use for further applications.

Herniarin-loaded solid lipid nanoparticles: promising molecular mechanism and therapeutic potential against pancreatic cancer line.

The notion of cancer therapy is intrinsically subjected to multiple challenges due to the drug resistance and drug toxicity for normal tissues. Herniarin (7-methoxycoumarin) belongs to the naturally occurring aromatic phytochemicals and coumarins. Considering the boosting effect of nanocarriers in drug delivery, we investigated the proapoptotic, anti-metastatic properties, and molecular mechanism of herniarin-loaded solid lipid nanoparticles on human gastric adenocarcinoma (AGS), human colon adenocarcinoma (HT-29), human pancreatic carcinoma (Panc-1), and normal human skin fibroblast (HFF) cell lines. The cytotoxicity of synthesized nanoparticle have been tested using MTT assay. The obtained results manifested that concentration of herniarin that exerts 50% cell growth inhibition (IC50) against HT-29, AGS, and Panc-1 was calculated 138.34, 123.46, and 83.744 µL, respectively. Given that nanoparticles showed lowest IC50 values on Panc-1 cell line, these cells were selected for further analysis. The apoptosis induction and cell cycle arrest were examined performing real-time PCR, flow cytometry, and DAPI/acridine orange-propidium iodide staining. The expression of apoptosis-related genes, including BCL-2, was decreased, while the expression of CASP9, CASP8, and CASP3 was increased in response to the treatment. Moreover, the expression of metastasis-related gene (MMP2) was significantly suppressed under Her-SLN-NPs treatment. According to the flow cytometry findings, we observed no cell cycle arrest at any stage. Our funding manifested herniarin encapsulated solid lipid nanoparticles has potent therapeutic target against Panc-1 cell line.

Design of novel water-soluble isoxazole-based antimicrobial agents and evaluation of their cytotoxicity and acute toxicity

Based on the readily available 3-organyl-5-(chloromethyl)isoxazoles, a number of previously unknown water-soluble conjugates of isoxazoles with thiourea, amino acids, some secondary and tertiary amines, and thioglycolic acid were synthesized. The bacteriostatic activity of aforementioned compounds has been studied against Enterococcus durans B-603, Bacillus subtilis B-407, Rhodococcus qingshengii Ac-2784D, and Escherichia coli B-1238 microorganisms (provided by All-Russian Collection of Microorganisms, VKM). The influence of the nature of the substituents in positions 3 and 5 of the isoxazole ring on the antimicrobial activity of the obtained compounds has been determined. It is found that the highest bacteriostatic effect is observed for compounds containing 4-methoxyphenyl or 5-nitrofuran-2-yl substituents in position 3 of the isoxazole ring as well as methylene group in position 5 bearing residues of l-proline or N-Ac-l-cysteine (5a–d, MIC 0.06–2.5 µg/ml). The leading compounds showed low cytotoxicity on normal human skin fibroblast cells (NAF1nor) and low acute toxicity on mice in comparison with the well-known isoxazole-containing antibiotic oxacillin.

Core-Shell Nanostructured Drug Delivery Platform Based on Biocompatible Metal-Organic Framework-Ligated Polyethyleneimine for Targeted Hepatocellular Carcinoma Therapy.

Multifunctional nanosized metal-organic frameworks (NMOFs) have advanced rapidly over the past decade to develop drug delivery systems (DDSs). These material systems still lack precise and selective cellular targeting, as well as the fast release of the quantity of drugs that are simply adsorbed within and on the external surface of nanocarriers, which hinders their application in the drug delivery. Herein, we designed a biocompatible Zr-based NMOF with an engineered core and the hepatic tumor-targeting ligand, glycyrrhetinic acid grafted to polyethyleneimine (PEI) as the shell. The improved core-shell serves as a superior nanoplatform for efficient controlled and active delivery of the anticancer drug doxorubicin (DOX) against hepatic cancer cells (HepG2 cells). In addition to their high loading capacity of 23%, the developed nanostructure DOX@NMOF-PEI-GA showed an acidic pH-stimulated response and extended the drug release time to 9 days as well as enhanced the selectivity toward the tumor cells. Interestingly, the DOX-free nanostructures showed a minimal toxic effect on both normal human skin fibroblast (HSF) and hepatic cancer cell line (HepG2), but the DOX-loaded nanostructures exhibited a superior killing effect toward the hepatic tumor, thus opening the way for the active drug delivery and achieving efficient cancer therapy applications.

Expression Strategy of Soluble Recombinant Human TGF-β3 in Escherichia coli: sfGFP -Fusion Tag

Transforming growth factor-beta 3 (TGF-β3) is an important cytokine involved in various biological processes. TGF-β3 is used as a scar-reducing antifibrotic agent for acute and chronic wounds and fibrosing disorders. TGF-β3, a valuable therapeutic protein, is produced recombinantly in different expression systems. TGF-β3, produced in the Escherichia coli (E. coli) expression system, widely used due to its various advantages in recombinant production, is commercially available. However, the main problem encountered in protein expression in E. coli cells is the formation of an inclusion body. Various approaches have been developed to solve this problem. The use of a fusion tag is one of the most powerful strategies used to obtain protein in the soluble active form in the E. coli expression system. Superfolder GFP (sfGFP) is one of the fusion tags used to increase the solubility of the fusion partner in E. coli. In this study, TGF-β3 with sfGFP fusion tag (sfGFP-TGFβ3) was successfully produced in soluble form in E. coli BL21 (DE3) in high yield and purity for the first time. Purified protein was identified by western blot and SDS-PAGE. 20 mg of protein with 98% purity was obtained from 1 L of bacterial culture. It was determined that the obtained high purity protein did not have a cytotoxic effect on BJ normal human skin fibroblast cells. The impact of sfGFP-TGFβ3 fusion protein on wound healing was evaluated with in vitro scratch wound healing assay. The results showed that the sfGFP-TGFβ3 fusion protein produced in soluble form in the E. coli expression system has the potential to support the wound healing process.

Green Synthesis of Highly Fluorescent Carbon Dots from Bovine Serum Albumin for Linezolid Drug Delivery as Potential Wound Healing Biomaterial: Bio-Synergistic Approach, Antibacterial Activity, and In Vitro and Ex Vivo Evaluation

A simple and green approach was developed to produce novel highly fluorescent bovine serum albumin carbon dots (BCDs) via facile one-step hydrothermal treatment, using bovine serum albumin as a precursor carbon source. Inherent blue photoluminescence of the synthesized BCDs provided a maximum photostability of 90.5 ± 1.2% and was characterized via TEM, FT-IR, XPS, XRD, UV-visible, and zeta potential analyses. By virtue of their extremely small size, intrinsic optical and photoluminescence properties, superior photostability, and useful non-covalent interactions with the synthetic oxazolidinone antibiotic linezolid (LNZ), BCDs were investigated as fluorescent nano-biocarriers for LNZ drug delivery. The release profile of LNZ from the drug delivery system (LNZ-BCDs) revealed a distinct biphasic release, which is beneficial for mollifying the lethal incidents associated with wound infection. The effective wound healing performance of the developed LNZ-BCDs were evaluated through various in vitro and ex vivo assays such as MTT, ex vivo hemolysis, in vitro antibacterial activity, in vitro skin-related enzyme inhibition, and scratch wound healing assays. The examination of LNZ-BCDs as an efficient wound healing biomaterial illustrated excellent biocompatibility and low cytotoxicity against normal human skin fibroblast (HSF) cell line, indicating distinct antibacterial activity against the most common wound infectious pathogens including Staphylococcus aureus (ATCC® 25922) and methicillin-resistant Staphylococcus aureus, robust anti-elastase, anti-collagenase, and anti-tyrosinase activities, and enhanced cell proliferation and migration effect. The obtained results confirmed the feasibility of using the newly designed fluorescent LNZ-BCDs nano-bioconjugate as a unique antibacterial biomaterial for effective wound healing and tissue regeneration. Besides, the greenly synthesized BCDs could be considered as a great potential substitute for toxic nanoparticles in biomedical applications due to their biocompatibility and intense fluorescence characteristics and in pharmaceutical industries as promising drug delivery nano-biocarriers for effective wound healing applications.

Safety and Efficacy of Pure and a Nanosuspension of D-limonene for Controlling Pigeon Lice.

This study investigated the safety and efficacy of two forms of D-limonene (DL) against Columbicola columbae (pigeon feather lice); pure and a nanoemulsion formulation (DLN). The cell cytotoxicity of the prepared forms of DL/DLN was investigated using skin cell lines. In vitro and ex vivo bioassays were applied on lice. The ex vivo bioassay was done on cut feathers containing lice eggs. The in vivo experiment was conducted on pigeons naturally infested by lice. The infested pigeons were treated with DL, DLN, or deltamethrin (D) as a positive control. Both forms of D-limonene were found to be safe when applied to the normal human skin fibroblast cell line, but DLN was toxic to skin cell carcinoma. The in vitro and ex vivo results of both DL and DLN forms were similar. All eggs treated with DL, DLN, and D failed to hatch (100%). The in vivo results showed complete elimination of lice 24 h post-treatment (PT), and biochemical analysis showed that the treated birds retained normal kidney and liver functions. Treated groups also showed improved productivity in the 4 months PT. In conclusion, DL and DLN are safe and effective in controlling feather lice infestation in pigeons and successful treatment encourages bird productivity.

Phenethyl Isothiocyanate-Conjugated Chitosan Oligosaccharide Nanophotosensitizers for Photodynamic Treatment of Human Cancer Cells.

The aim of this study is to synthesize phenethyl-conjugated chitosan oligosaccharide (COS) (abbreviated as ChitoPEITC) conjugates and then fabricate chlorin E6 (Ce6)-incorporated nanophotosensitizers for photodynamic therapy (PDT) of HCT-116 colon carcinoma cells. PEITC was conjugated with the amine group of COS. Ce6-incorporated nanophotosensitizers using ChitoPEITC (ChitoPEITC nanophotosensitizers) were fabricated by dialysis method. 1H nuclear magnetic resonance (NMR) spectra showed that specific peaks of COS and PEITC were observed at ChitoPEITC conjugates. Transmission electron microscope (TEM) confirmed that ChitoPEITC nanophotosensitizers have spherical shapes with small hydrodynamic diameters less than 200 nm. The higher PEITC contents in the ChitoPEITC copolymer resulted in a slower release rate of Ce6 from nanophotosensitizers. Furthermore, the higher Ce6 contents resulted in a slower release rate of Ce6. In cell culture study, ChitoPEITC nanophotosensitizers showed low toxicity against normal CCD986Sk human skin fibroblast cells and HCT-116 human colon carcinoma cells in the absence of light irradiation. ChitoPEITC nanophotosensitizers showed a significantly higher Ce6 uptake ratio than that of free Ce6. Under light irradiation, cellular reactive oxygen species (ROS) production of nanophotosensitizers was significantly higher than that of free Ce6. Especially, PEITC and/or ChitoPEITC themselves contributed to the production of cellular ROS regardless of light irradiation. ChitoPEITC nanophotosensitizers showed significantly higher PDT efficacy against HCT-116 cells than that of free Ce6. These results indicate that ChitoPEITC nanophotosensitizers have superior potential in Ce6 uptake, ROS production and PDT efficacy. In the HCT-116 cell-bearing mice tumor-xenograft model, ChitoPEITC nanophotosensitizers efficiently inhibited growth of tumor volume rather than free Ce6. In the animal imaging study, ChitoPEITC nanophotosensitizers were concentrated in the tumor tissue, i.e., fluorescence intensity in the tumor tissue was stronger than that of other tissues. We suggest that ChitoPEITC nanophotosensitizers are a promising candidate for the treatment of human colon cancer cells.

Triptonide Inhibits the Cervical Cancer Cell Growth via Downregulating the RTKs and Inactivating the Akt-mTOR Pathway

The high incidence and mortality of cervical cancer (CC) require an urgent need for exploring novel valuable therapeutics. Triptonide (TN) is a small molecule monomer extracted from the Chinese herb Tripterygium wilfordii Hook. Our results showed that TN, at only nanomolar concentrations, strongly inhibited growth, colony formation, proliferation, migration, and invasion of established and primary human cervical cancer cells. TN induced apoptosis and cell cycle arrest in cervical cancer cells. Moreover, cervical cancer cell in vitro migration and invasion were suppressed by TN. It was however noncytotoxic and proapoptotic to normal cervical epithelial cells and human skin fibroblast cells. Gene set enrichment analysis (GSEA) of RNA sequencing data of differentially expressed genes (DEGs) in TN-treated cervical cancer cells implied that DEGs were enriched in the receptor tyrosine kinase (RTK) signaling and PI3K-Akt-mTOR cascade. In cervical cancer cells, RTKs, including EGFR and PDGFRα, were significantly downregulated and Akt-mTOR activation was largely inhibited after TN treatment. In vivo, oral administration of TN significantly inhibited subcutaneous cervical cancer xenograft growth in nude mice. EGFR and PDGFRα downregulation as well as Akt-mTOR inactivation was detected in TN-treated HeLa xenograft tumor tissues. Thus, TN inhibits human cervical cancer cell growth in vitro and in vivo. Its anticervical cancer activity was associated with RTK downregulation and Akt-mTOR inactivation.

Estimation of Calcium Titanate or Erbium Oxide Nanoparticles Induced Cytotoxicity and Genotoxicity in Normal HSF Cells

Extensive uses of calcium titanate nanoparticles (CaTiO3-NPs) and erbium oxide nanoparticles (Er2O3-NPs) increase their release into the environment and human exposure, particularly through skin contact. However, there are almost no studies available on the effect of these nanoparticles on skin integrity. Therefore, this study was undertaken to estimate CaTiO3-NP- or Er2O3-NP-induced cytotoxicity and genotoxicity in normal human skin fibroblast (HSF) cells. Cell viability was measured using sulforhodamine B (SRB) assay, while the level of DNA damage was detected using the alkaline comet assay. The intracellular levels of reactive oxygen species (ROS) as well as the expression level of p53, Bax, and Bcl2 genes were detected. Although the viability of HSF cells was non-markedly changed after 24 h, prolonged treatment with CaTiO3-NPs or Er2O3-NPs for 72 h induced concentration-dependent death of HSF cells. Treatment of normal HSF cells with IC50/72 h of CaTiO3-NPs or Er2O3-NPs did not cause marked changes in the intracellular level of ROS, DNA damage parameters, and expression levels of apoptosis genes compared to their values in the untreated HSF cells. We thus concluded that CaTiO3-NPs or Er2O3-NPs cause time- and concentration-dependent cytotoxicity toward normal HSF cells. However, safe and non-genotoxic effects were demonstrated by the apparent non-significant changes in intracellular ROS level, DNA integrity, and apoptotic genes’ expression after exposure of normal HSF cells to nanoparticles. Thus, it is recommended that further studies be conducted to further understand the toxic and biological effects of CaTiO3-NPs and Er2O3-NPs.

Fine-tuning of the pharmacological potential of novel thiazolium ionic liquids by anion alteration.

A novel series of thiazolium ionic liquids (TILs) bound to chloride (2a–c), tetrafluoroborate (BF4) (3a–c), and bis-(trifluoromethanesulfonimide) (Tf2N) anions (4a–c) was synthesized and their physicochemical characteristics were investigated using various microanalytical techniques. The pharmacological potential of the new TILs was assessed as chemotherapeutic agents for bacterial infections and ovarian cancer (SKOV-3). Notably, ILs with the same cations become more bactericidal upon their binding with the strongest chaotropic anion (TN2f). The in vitro toxicity of the TILs toward ovarian carcinoma cell lines (SKOV-3) and normal human skin fibroblast cells (HSF) revealed that all tested TILs have the capacity to induce a dose- and time-dependent decline in SKOV-3 cell viability, with Tf2N-linked TILs (4a–c) having a preferable efficacy. In addition, the new compounds showed excellent selectivity for cancer cells (SKOV-3) over healthy cells (HSF). [iPBzTh][Tf2N] (4b) is the most cytotoxic and specific one and may act as a promising anti-ovarian cancer agent.

Valorization of spent coffee grounds as the specialty material for dullness and aging of skin treatments

BackgroundCoffee beans contain oil with health benefits from fatty acids. The unprocessed and processed coffee beans are mostly identical in coffee oil quality and are substantively supplied for certain industries. However, the cost-effective valorization of specialty ingredients from spent coffee grounds for cosmetics is sparely presented. Linoleic acid-rich spent coffee oil, as a specialty material for skin lightening and antiaging cosmetics, is objectively to be presented.ResultsSpent coffee oils were prepared by different methods. The most cost-effective material with a high extraction yield, linoleic acid content and unsaturated/saturated fatty acid (UFA/SFA) ratio (13.21 ± 0.25, 32.09% and 0.97) was modified. The modified oil was boosted in linoleic acid (77.20% or 140.57% improvement) and the UFA/SFA ratio (33.12). The physicochemical properties of the oil were applicable for cosmetics as per its safety profiles in B16F10 melanoma and normal human skin fibroblast cells. The oil significantly better inhibited cellular melanogenesis than kojic and linoleic acids (p < 0.01), with prominent tyrosinase and TRP-2 inhibitions. The cellular antioxidant activity of the oil was comparable to those of ascorbic and linoleic acids. The collagen stimulating efficacy of the oil was significantly better than that of ascorbic but comparable to that of linoleic acid as indicated by the MMP-2 inhibitory activities (p < 0.01 and p < 0.001, respectively).ConclusionsThe oil is a specialty material for skin brightening and skin wrinkle reduction/skin elasticity improvement products. A successive circular bioeconomy of spent coffee ground waste in a more profitable cosmetic industry is indicated.Graphic abstract

Novel thiazolium ionic liquids-tagged bicyclo-palladium(II) Schiff base complexes; Synthesis, characterization and in vitro cytotoxicity toward ovarian cancer

The high toxicity and side effects of the most widely used cancer chemotherapeutic drug (Cisplatin, CDDP) induced always an urgent need for exploring new safe chemotherapeutic agents (CTAs). To that end, a novel series of physiologically stable and water-soluble thiazolium ionic liquids (ILs)-tagged Schiff bases (3a-c) and their bicyclo-palladium(II) complexes (4a-c) were synthesized with high yields and their physicochemical characteristics were determined using diverse analytical techniques. New thiazolium ILs-based congeners were in vitro assessed as CTAs for ovarian carcinoma cell line (SKOV-3). For selectivity level checking, the effect of these compounds on normal human skin fibroblast cells (HSF) was also investigated. It can be highlighted that all thiazolium derivatives induced a dose- and time-dependent decline in SKOV-3 cell viability with a preferable efficacy for Pd(II) complexes over their corresponding thiazolium Schiff bases. In addition, the new compounds showed excellent selectivity for cancer cells (SKOV-3) over the healthy cells (HSF).

Synthesis and Cytotoxicity Evaluation of Spirocyclic Bromotyrosine Clavatadine C Analogs.

Marine-originated spirocyclic bromotyrosines are considered as promising scaffolds for new anticancer drugs. In a continuation of our research to develop potent and more selective anticancer compounds, we synthesized a library of 32 spirocyclic clavatadine analogs by replacing the agmatine, i.e., 4-(aminobutyl)guanidine, side chain with different substituents. These compounds were tested for cytotoxicity against skin cancer using the human melanoma cell line (A-375) and normal human skin fibroblast cell line (Hs27). The highest cytotoxicity against the A-375 cell line was observed for dichloro compound 18 (CC50 0.4 ± 0.3 µM, selectivity index (SI) 2). The variation of selectivity ranged from SI 0.4 to reach 2.4 for the pyridin-2-yl derivative 29 and hydrazide analog of 2-picoline 37. The structure–activity relationships of the compounds in respect to cytotoxicity and selectivity toward cancer cell lines are discussed.

Abstract 2090: TP73 expression may be influenced by DNA methylation in human tumorigenesis

Abstract Epigenetic events that cause alterations in gene expression are common in human cancers. The connection between TP73 expression and its epigenetic functionality in tumorigenesis has scarcely been explored. As a transcription factor, TP73 (aka, p73) like its cousin, p53, is activated in response to DNA damage and regulates the expression of downstream genes involved in cell cycle arrest and apoptosis. However, there are other compounding functions of this gene that reflect its non-tumor-related characteristics, thus making it very difficult to assess its specific role in tumorigenesis. Our previous work showed that DNA methylation activates TP73 expression in hepatocellular carcinoma (HCC) and gastrointestinal cancer. In this study, we determined TP73 expression in normal human mammary epithelial cells (HMECs), human non-cancerous Li-Fraumeni Syndrome (LFS) skin fibroblast cells, human breast cancer cell lines (MCF7, MDA-MB-231 &amp; MDA-MB-468), prostate cancer cell lines (LNCaP &amp; MDA-PCa2b), lung cancer cell lines (A549 &amp; NCI-H596), neuroblastoma cell lines (IMR32 &amp; SK-N-SH) and normal human skin fibroblast cell line (HS27). The results show that TP73 was expressed solely in cancer cells. Subsequent immunohistochemical analyses of TP73 expression in cancerous and adjacent non-cancerous liver tissues of HCC patients clearly showed that TP73 expression was exclusively evident in cancerous tissues but not in the adjacent normal liver tissues. Mechanistically, methylation-specific PCR and bisulfite sequencing studies revealed that TP73 promoter is activated only in cancer cells and this activation occurs via DNA methylation. Moreover, ChIP assays demonstrated that a CTCF (a chromosomal networking protein CCCTC binding factor) and tumor protein p53 (TP53) bind to TP73 promoter and regulate TP73 expression. Our observations demonstrate that a positive correlation in tumorigenesis exists between TP73 expression and DNA methylation in promoter regions of TP73. These findings suggest that TP73's role in carcinogenesis may prove to be pivotal for the development of future diagnostic and therapeutic applications. Citation Format: Zhixing Yao, David R. Yao, William Yu, Ahmed Malki, Zaki A. Sherif. TP73 expression may be influenced by DNA methylation in human tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2090.

Design and Synthesis of Lipopolysaccharide-Binding Antimicrobial Peptides Based on Truncated Rabbit and Human CAP18 Peptides and Evaluation of Their Action Mechanism.

Lipopolysaccharide (LPS) is a toxic and immunogenic agent for human. Additionally, LPS is a good target for some antimicrobial compounds, including antimicrobial peptides (AMPs). LPS-binding peptides (LBPs) can recognize and neutralize LPS. Rabbit and human cathelicidins are AMPs with LPS-binding activity. In this study, we designed and synthesized two new truncated LBPs from rabbit and human CAP18 peptides by in silico methods. After synthesis of peptides, the antimicrobial properties and LPS-binding activity of these peptides were evaluated. The parental rabbit and human CAP18 peptides were selected as positive controls. Next, the changes in the secondary structure of these peptides before and after treatment with LPS were measured by circular dichroism (CD). Human cytotoxicity of the peptides was evaluated by MTT and red blood cells (RBCs) hemolysis assays. Finally, field emission scanning electron microscopy (FE-SEM), confocal microscopy, and flow cytometry were performed to study the action mechanism of these peptides. Results indicated that the hCap18 and rCap18 had antibacterial activity (at a MIC of 4-128μg/mL). The results of the quantitative LAL test demonstrated that LPS-binding activity of hCap18 peptide was better than rCap18, while rCap18 peptide had better antimicrobial properties. Furthermore, rCap18 had less cytotoxicity than hCap18. However, both peptides were nontoxic for normal human skin fibroblast cell in MIC range. In conclusion, rCap18 has good antibacterial properties, while hCap18 can be tested as a diagnostic molecule in our future studies.

Axl Inhibitor R428 Enhances TRAIL-Mediated Apoptosis Through Downregulation of c-FLIP and Survivin Expression in Renal Carcinoma.

R428, a selective small molecule Axl inhibitor, is known to have anti-cancer effects, such as inhibition of invasion and proliferation and induction of cell death in cancer cells. The Axl receptor tyrosine kinase is highly expressed in cancer cells and the level of Axl expression is associated with survival, metastasis, and drug resistance of many cancer cells. However, the effect of Axl inhibition on overcoming anti-cancer drugs resistance is unclear. Therefore, we investigated the capability of Axl inhibition as a therapeutic agent for the induction of TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) sensitivity. In this study, R428 markedly sensitized cancer cells to TRAIL-induced apoptotic cell death, but not in normal human skin fibroblast (HSF) and human umbilical vein cells (EA.hy926). Moreover, knockdown of Axl by siRNA also increased TRAIL-induced apoptosis. R428 decreased c-FLIP proteins levels via induction of miR-708 expression and survivin protein levels at the post-translational level, and we found that knockdown of Axl also decreased both c-FLIP and survivin protein expression. Overexpression of c-FLIP and survivin markedly inhibited R428 plus TRAIL-induced apoptosis. Furthermore, R428 sensitized cancer cells to multiple anti-cancer drugs-mediated cell death. Our results provide that inhibition of Axl could improve sensitivity to TRAIL through downregulation of c-FLIP and survivin expression in renal carcinoma cells. Taken together, Axl may be a tempting target to overcome TRAIL resistance.