Inhibition of epidermal growth factor receptor by ferulic acid and 4-vinylguaiacol in human breast cancer cells

Objectives

To examine the potential of ferulic acid and 4-vinylguaiacol for inhibiting epidermal growth factor receptor (EGFR) in human breast cancer cells in vitro.

Results

Ferulic acid and 4-vinylguaiacol limit the EGF (epidermal growth factor)-induced breast cancer proliferation and new DNA synthesis. Western blot analysis revealed both ferulic acid and 4-vinylguaiacol exhibit sustained inhibition of EGFR activation through down-regulation of Tyr 1068 autophosphorylation. Molecular docking analysis shows ferulic acid forming hydrogen bond interaction with Lys 745 and Met 793 whereas, 4-vinylguaiacol forms two hydrogen bonds with Phe 856 and exhibits stronger hydrophobic interactions with multiple amino acid residues at the EGFR kinase domain.

Conclusions

Ferulic acid and 4-vinylguaiacol could serve as a potential structure for the development of new small molecule therapeutics against EGFR.

     

The role of Sprouty1 in the proliferation,differentiation and apoptosis of epidermal keratinocytes

Objectives

Sprouty (SPRY) 1 is one of the SPRY proteins that inhibits signalling from various growth factors pathways and has also been known as a tumour suppressor in various malignancies. However, no study elucidates the role of SPRY1 in the skin. Our study was conducted to determine the function of SPRY1 in human keratinocytes and the epidermis.

Materials and methods

In vitro primary cultured epidermal keratinocytes were used to investigate the proliferation, differentiation and apoptosis of these cells. We also established overexpression of SPRY1 in vitro and K14‐SPRY1 transgenic mice.

Results

SPRY1 was mainly located in the cytoplasm of the epidermal keratinocytes from the granular epidermal layer of the skin and cultured cells. Overexpressed SPRY1 in keratinocytes resulted in up‐regulation of P21, P27 and down‐regulation of cyclin B1; decrease in MMP3 and integrin α6. SPRY1‐overexpressed primary keratinocytes exhibited a lower proliferation and migration capability and higher rates of apoptosis. Epidermis of SPRY1‐TG mice represented delayed wound healing. Proteomics analysis and GO enrichment showed DEPs of SPRY1 TG mice epidermis is significantly enriched in immune‐ and inflammatory‐associated biological process.

Conclusions

In summary, SPRY1 expression was inversely correlated with cell proliferation, migration and promote cell apoptosis of keratinocytes. SPRY1 maybe a negative feedback regulator in normal human epidermal keratinocytes and cutaneous inflammatory responses. Our study raised the possibility that enhancing expression of SPRY1 may have the potential to promote anti‐inflammatory effects.

     

Selenium unmasks protective iron armor: A possible defense against cutaneous inflammation and cancer

Background

A link between selenium deficiency and inflammatory skin diseases have been noted by many, but this link is still not well understood. We have previously studied the efficacy of ceramide analogs, based on the fire ant venom Solenopsin A, against our psoriasis animal model. Treatment of animals with solenopsin analogs resulted in significantly improved skin as well as in a coordinate downregulation of selenoproteins, namely Glutathione Peroxidase 4 (GPX4). We thus hypothesize that ferroptosis may be a physiologic process that may protect the skin from both inflammatory and neoplastic processes.

Endoglin based in vivo near-infrared fluorescence imaging of tumor models in mice using activatable liposomes

Background

Endoglin (CD105) is overexpressed on tumor cells and tumor vasculatures, making it a potential target for diagnostic imaging and therapy of different neoplasms. Therefore, studies on nanocarrier systems designed for endoglin-directed diagnostic and drug delivery purposes would expose the feasibility of targeting endoglin with therapeutics.

Selenium-regulated hierarchy of human selenoproteome in cancerous and immortalized cells lines

Background

Selenoproteins (25 genes in human) co-translationally incorporate selenocysteine using a UGA codon, normally used as a stop signal. The human selenoproteome is primarily regulated by selenium bioavailability with a tissue-specific hierarchy.

Overexpression of Galectin-7 in Mouse Epidermis Leads to Loss of Cell Junctions and Defective Skin Repair

Background

The proteins of the galectin family are implicated in many cellular processes, including cell interactions, polarity, intracellular trafficking, and signal transduction. In human and mouse, galectin-7 is almost exclusively expressed in stratified epithelia, notably in the epidermis. Galectin-7 expression is also altered in several human tumors of epithelial origin. This study aimed at dissecting the consequences of galectin-7 overexpression on epidermis structure and functions in vivo.

Methods

We established transgenic mice specifically overexpressing galectin-7 in the basal epidermal keratinocytes and analyzed the consequences on untreated skin and after UVB irradiation or mechanical injury.

Results

The intercellular cohesion of the epidermis is impaired in transgenic animals, with gaps developing between adjacent keratinocytes, associated with loss of adherens junctions. The epidermal architecture is aberrant with perturbations in the multilayered cellular organisation of the tissue, and structural defects in the basement membrane. These transgenic animals displayed a reduced re-epithelialisation potential following superficial wound, due to a defective collective migration of keratinocytes. Finally, a single mild dose of UVB induced an abnormal apoptotic response in the transgenic epidermis.

Conclusion

These results indicate that an excess of galectin-7 leads to a destabilisation of adherens junctions associated with defects in epidermal repair. As this phenotype shares similarities with that of galectin-7 null mutant mice, we conclude that a critical level of this protein is required for maintaining proper epidermal homeostasis. This study brings new insight into the mode of action of galectins in normal and pathological situations.     

Convergent evolution of cysteine-rich proteins in feathers and hair

Background

Feathers and hair consist of cornified epidermal keratinocytes in which proteins are crosslinked via disulfide bonds between cysteine residues of structural proteins to establish mechanical resilience. Cysteine-rich keratin-associated proteins (KRTAPs) are important components of hair whereas the molecular components of feathers have remained incompletely known. Recently, we have identified a chicken gene, named epidermal differentiation cysteine-rich protein (EDCRP), that encodes a protein with a cysteine content of 36%. Here we have investigated the putative role of EDCRP in the molecular architecture and evolution of feathers.

Results

Comparative genomics showed that the presence of an EDCRP gene and the high cysteine content of the encoded proteins are conserved among birds. Avian EDCRPs contain a species-specific number of sequence repeats with the consensus sequence CCDPCQ(K/Q)(S/P)V, thus resembling mammalian cysteine-rich KRTAPs which also contain sequence repeats of similar sequence. However, differences in gene loci and exon-intron structures suggest that EDCRP and KRTAPs have not evolved from a common gene ancestor but represent the products of convergent sequence evolution. mRNA in situ hybridization demonstrated that chicken EDCRP is expressed in the subperiderm layer of the embryonic epidermis and in the barbule cells of growing feathers. This expression pattern supports the hypothesis that feathers are evolutionarily derived from the subperiderm.

Conclusions

The results of this study suggest that convergent sequence evolution of avian EDCRP and mammalian KRTAPs has contributed to independent evolution of feathers and hair, respectively.

     

Lipopolysaccharide induces bacterial autophagy in epithelial keratinocytes of the gingival sulcus

Background

Interactions of resident bacteria and/or their producing lipopolysaccharide (LPS) with sulcular epithelial keratinocytes may be regulated by autophagy in the gingival sulcus. In this study, we investigated an induction of bacterial autophagy in exfoliative sulcular keratinocytes of the gingival sulcus and cultured keratinocytes treated with Porphyromonas gingivalis-originated LPS (PgLPS).

Results

Exfoliative sulcular keratinocytes showed an induction of autophagy, in addition to increased expression of LPS-mediated factors including lipopolysaccharide-binding protein and toll-like receptors (TLRs), leading to co-localization of bacteria with autophagosomes. In contrast, exfoliative keratinocytes from the free gingiva did not show similar autophagy. Autophagy activity in human cultured keratinocyte cells (HaCaT) was induced by PgLPS, which was dependent partially on the AMP-activated protein kinase (AMPK) pathway via increased intracellular reactive oxygen species (ROS) and was in association with an activation of TLR4 signaling. After incubation of cultured keratinocytes with E.coli BioParticles following PgLPS stimulation, co-localization of bioparticles with autophagosomes was enhanced. Conversely, blockage of autophagy with 3-methyladenin and LPS-binding with polymyxin B led to significant reduction of co-localization of particles with autophagosomes.

Conclusion

These findings indicate that PgLPS-induced autophagy is at least partially responsible for interaction between bacteria and sulcular keratinocytes in the gingival sulcus.

     

Dual blockade of VEGFR1 and VEGFR2 by a novel peptide abrogates VEGF-driven angiogenesis,tumor growth,and metastasis through PI3K/AKT and MAPK/ERK1/2 pathway

Background

Neutralization of vascular endothelial growth factor receptor 1 (VEGFR1) and/or VEGFR2 is a widely used means of inhibiting tumor angiogenesis.

Differentiation into neurons of rat bone marrow-derived mesenchymal stem cells

Purpose

It has been reported that mesenchymal stem cells (MSCs) can differentiate into neurons as an effect of adding extraneous factors, such as β-mercaptoethanol, dimethyl sulfoxide and butylated hydroxyanisole. However, many of these compounds could harm MSCs and the human body, which restricts their application. We examined whether MSCs could differentiate into neuron-like cells under the influence of natural growth factors, such as epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), insulin-like growth factor 1 (IGF-1, and neurotrophin 3 (NT-3).

Methods

MSCs were collected from rat bone marrow using the plastic adherent selection method, and induced in culture media to which was added different combinations of EGF, bFGF, IGF-1 and NT-3. The shape of the induced cells was observed daily and the differentiated cells were characterized by immunocytochemistry with neural-specific markers.

Result

With bFGF and NT-3 in the medium, the induced cells became slim, gradually developing protruding processes, with parts of them forming net- or ring-like structures. Cells with processes showed expression of microtubule-associated protein 2 (MAP2) and nestin (NES), which was enhanced when bFGF and NT-3 were added in combination. However, with IGF-1 added to the medium, there was no evidence of neurite-like processes or any net- or ring-like structures; the MSCs retained their round or slim shape.

Conclusion

Using natural cytokines in vitro, MSCs successfully differentiated into neuron-like cells. Our study confirms that bFGF and NT-3 exerts a neural-induction effect on the differentiation of MSCs, but that IGF has a rather negative effect on this process.

     

Myrtenal-induced V-ATPase inhibition - A toxicity mechanism behind tumor cell death and suppressed migration and invasion in melanoma

Background

Metastatic tumor cells have acidic extracellular pH and differential electrochemical H⁺ gradients generated across their cell membranes by V-type H⁺-ATPases. This study shows that inhibition of the V-ATPases by the plant-derived monoterpene Myrtenal results in tumor cell death and decreased metastatic dissemination in mice.

Comparative study on different therapies on patients with primary central nervous system lymphoma

Objective

To compare and analyze three therapies on patients with primary central nervous system lymphoma (PCNSL), aiming to provide evidences for future treatment and prognosis.

Stabilization of G-quadruplex structure on vascular endothelial growth factor gene promoter depends on CpG methylation site and cation type

Background

DNA methylation at the 5-position of cytosine is an epigenetic modification of CpG dinucleotides. In addition to CpG methylation, the G-quadruplex (G4) structure has been reported as a regulator of gene expression. The identification of G4 forming sequences in CpG islands suggests an involvement of CpG-methylated G4 structures in biological processes; however, few reports have addressed the effects of CpG methylation on G4 structure.

Kinetic evidence for interaction of TMPyP4 with two different G-quadruplex conformations of human telomeric DNA

Background

Stabilization of G-quadruplex helices by small ligands has attracted growing attention because they inhibit the activity of the enzyme telomerase, which is overexpressed in > 80% cancer cells. TMPyP4, one of the most studied G-quadruplex ligands, is used as a model to show that the ligands can exhibit different binding features with different conformations of a human telomeric specific sequence.

Characterization of heparan sulfate N-deacetylase/N-sulfotransferase isoform 4 using synthetic oligosaccharide substrates

Background

The final structure of heparan sulfate chains is strictly regulated in vivo, though the biosynthesis is not guided by a template process. N-deacetylase/N-sulfotransferase (NDST) is the first modification enzyme in the HS biosynthetic pathway. The N-sulfo groups introduced by NDST are reportedly involved in determination of the susceptibility to subsequent processes catalyzed by C₅-epimerse and 3-O-sulfotransferases. Understanding the substrate specificities of the four human NDST isoforms has become central to uncovering the regulatory mechanism of HS biosynthesis.

A combined literature and in silico analysis enlightens the role of the NDRG family in the gut

Background

The N-Myc Downstream-Regulated Gene (NDRG) family comprises four members that function in cellular processes like proliferation and differentiation. While NDRG1 and NDRG2 are extensively studied, knowledge regarding NDRG3 and NDRG4, despite its recognition as a well-established early-detection marker for colorectal cancer (Cologuard®), is sparse.

Surface Plasmon Resonance kinetic analysis of the interaction between G-quadruplex nucleic acids and an anti-G-quadruplex monoclonal antibody

Background

G-quadruplexes (G4s) are nucleic acids secondary structures formed in guanine-rich sequences. Anti-G4 antibodies represent a tool for the direct investigation of G4s in cells. Surface Plasmon Resonance (SPR) is a highly sensitive technology, suitable for assessing the affinity between biomolecules. We here aimed at improving the orientation of an anti-G4 antibody on the SPR sensor chip to optimize detection of binding antigens.

Molecular mechanism of Arabidopsis thaliana profilins as antifungal proteins

Background

It remains an open question whether plant phloem sap proteins are functionally involved in plant defense mechanisms.