Resources

Research topics,
Latest news and updates

PUBLICATIONS

Self-assembling ELR-based nanoparticles as smart drug-delivery systems modulating cellular growth via Akt

This work investigates the physicochemical properties and in vitro accuracy of a genetically engineered drug-delivery system based on elastin-like block recombinamers. The DNA recombinant techniques allowed us to create this smart complex polymer containing bioactive sequences for internalization, lysosome activation under acidic pH, and blockage of cellular growth by a small peptide inhibitor. The recombinant polymer reversibly self-assembled when the temperature was increased above 15 °C into nanoparticles with a diameter of 72 nm and negative surface charge. Furthermore, smart nanoparticles were shown to enter in the cells via clathrin-dependent endocytosis and properly blocked phosphorylation and consequent activation of Akt kinase. This system provoked apoptosis-mediated cell death in breast and colorectal cancer cells, which possess higher expression levels of Akt, whereas noncancerous cells, such as endothelial cells, fibroblasts, and mesenchymal stem cells, were not affected. Hence, we conclude that the conformational complexity of this smart elastin-like recombinamer leads to achieving successful drug delivery in targeted cells and could be a promising approach as nanocarriers with bioactive peptides to modulate multiple cellular processes involved in different diseases.

Learn more

PUBLICATIONS

Effect of alternan versus chitosan on the biological properties of human mesenchymal stem cells

Alternan, an a-1,3- and a-1,6-linked glucan, is a polysaccharide that is produced by bacteria. Although the structure of alternan used in this study, an a-1,3- and a-1,6-linked glucan (hereafter referred to as alternan), has been comprehensively characterized, its function on cell biology, especially relative to cell growth and differentiation, has not been fully elucidated. In this study, we set forth to compare the effect of alternan versus chitosan on the biological properties of human mesenchymal stem cells (MSCs). The effect of chitosan on MSC differentiation has already been well characterized. The treated cells were determined for cell proliferation and differentiation capacity compared to untreated cells. The result showed that treatment by alternan or chitosan increased cell proliferation, as demonstrated by increased cell number and scratched regions that were fully restored in less time than it took to fully restore controls. Further investigation found that alternan and chitosan activates the toll-like receptor (TLR) pathway suggesting that these cells may be prone to differentiation. In agreement with this result, an increase in deposited calcium was observed in alternan- or chitosan-treated cells after osteogenic differentiation induction. However, adipogenic differentiation was significantly inhibited in the presence of chitosan, but no change was observed in alternan treatment. Taken together, these results demonstrate biological effects of alternan on human MSCs. Moreover, these novel roles of alternan may have important beneficial medical applications and may provide a basis from which stem cell therapies can be developed in the future.

Learn more

PUBLICATIONS

Establishment of two dimensional (2D) and three-dimensional (3D) melanoma primary cultures as a tool for in vitro drug resistance studies

Characteristics of melanoma cells have been deciphered by studies carried out in two dimensional cell cultures growing as adherent monolayers on the bottom of plastic flasks. Melanoma cells can be cultured with a considerable degree of success, and, depending on the further use of the cells obtained in the culture, methodologies have to be adjusted to obtain reliable results. Although there are many melanoma continuous cell lines, in vitro 2D and 3D melanoma primary cell culture may be a more useful model to investigate interactions between cancer cells and immune system, as well as the effect of cytotoxic treatments and personalized medicine in environments more similar to the physiological conditions. Here, we described a protocol which employs many strategies to obtain primary 2D and 3D melanoma cultures as a model to study cell–cell and cell–microenvironment interactions that must be considered to properly design personalized cancer treatments, as well as for testing novel anticancer drugs and drug delivery vehicles.

Learn more

PUBLICATIONS

Mouse fetal intestinal organoids - new model to study epithelial maturation from suckling to weaning

During the suckling-to-weaning transition, the intestinal epithelium matures, allowing digestion of solid food. Transplantation experiments with rodent fetal epithelium into subcutaneous tissue of adult animals suggest that this transition is intrinsically programmed and occurs in the absence of dietary or hormonal signals. Here, we show that organoids derived from mouse primary fetal intestinal epithelial cells express markers of late fetal and neonatal development. In a stable culture medium, these fetal epithelium-derived organoids lose all markers of neonatal epithelium and start expressing hallmarks of adult epithelium in a time frame that mirrors epithelial maturation in vivo. In vitro postnatal development of the fetal-derived organoids accelerates by dexamethasone, a drug used to accelerate intestinal maturation in vivo. Together, our data show that organoids derived from fetal epithelium undergo suckling-to-weaning transition, that the speed of maturation can be modulated, and that fetal organoids can be used to model the molecular mechanisms of postnatal epithelial maturation.

Learn more

PUBLICATIONS

The therapeutic potential of the insect metalloproteinase inhibitor against infections caused by Pseudomonas aeruginosa

The objective of this study was to investigate the therapeutic potential of the insect metalloproteinase inhibitor (IMPI) from Galleria mellonella, the only known specific inhibitor of M4 metalloproteinases. The fusion protein IMPI-GST (glutathione-S-transferase) was produced by fermentation in Escherichia coli and was tested for its ability to inhibit the proteolytic activity of the M4 metalloproteinases thermolysin and Pseudomonas elastase (PE), the latter a key virulence factor of the wound-associated and antibiotic-resistant pathogen Pseudomonas aeruginosa. We also tested the ability of IMPI to inhibit the secretome (Sec) of a P. aeruginosa strain obtained from a wound. We found that IMPI-GST inhibited thermolysin and PE in vitro and increased the viability of human keratinocytes exposed to Sec by inhibiting detachment caused by changes in cytoskeletal morphology. IMPI-GST also improved the cell migration rate in an in vitro wound assay and reduced the severity of necrosis caused by Sec in an ex vivo porcine wound model. The inhibition of virulence factors is a novel therapeutic approach against antibiotic resistant bacteria. Our results indicate that IMPI is a promising drug candidate for the treatment of P. aeruginosa infections.

Learn more

PUBLICATIONS

Investigations into the combined effects of gold nanoparticles and ionising radiations on cancer cell migration

Cell migration is a key physiological ability in wound healing, organ regeneration and cancer metastasis1,2. This ability in cancer cells enables them to invade the normal tissues in their vicinity. A few studies have revealed the suppressed cancer cell migration in the presence of gold nano-particles (AuNPs)3–6. In addition, alteration on cytoskeleton properties by x-irradiation has been reported7 . However, the close investigation for the effects of AuNPs on cancer cell migration have not been previously performed and the effects of AuNPs combined with X-ray irradiation also remained unclear. In this in vitro study, we investigated the effects of AuNPs on the cell migration for two types of cancer cells to determine the cellular response to the AuNPs. Furthermore, we investigated the combined effects of AuNPs and X-ray on cell migration.

Learn more

PUBLICATIONS

MDA-MB-231 breast cancer cells in their CSC population migrate towards low oxygen in a microfluidic gradient device

Most cancer deaths are caused by secondary tumors formed through metastasis, yet due to our limited understanding of this process, prevention remains a major challenge. Recently, cancer stem cells (CSCs) have been proposed as the source of metastases, but only little is known about their migratory behavior. Oxygen gradients in the tumor have been linked to directional migration of breast cancer cells. Here, we present a method to study the effect of oxygen gradients on the migratory behavior of breast CSCs using a microfluidic device. Our chip contains a chamber in which an oxygen gradient can be generated between hypoxic (<1%) and ambient (21%) conditions. We tracked the migration of CSCs obtained from MDA-MB-231 breast cancer cells, and found that their migration patterns do not differ from the average MDA-MB-231 population. Surprisingly, we found that the cells migrate towards low oxygen levels, in contrast with an earlier study. We hypothesize that in our device, migration is exclusively due to the pure oxygen gradient, whereas the effects of oxygen in earlier work were obscured by additional cues from the tumor microenvironment (e.g., nutrients and metabolites). These results open new research directions into the role of oxygen in directing cancer and CSC migration.

Learn more

PUBLICATIONS

Measuring spontaneous neutrophil motility signatures from a drop of blood using microfluidics

Neutrophils play an essential role in the protection against infection, as they are the most numerous circulating white blood cell population and the first responders to injury. Their numbers in blood are frequently measured in the clinic and used as an indicator of ongoing infections. During inflammation and sepsis, the ability of neutrophils to migrate is disrupted, which may increase the risk of infection, even when the neutrophil count is normal. However, measurements of neutrophil migration in patients are rarely performed because of the challenges of performing the migration assays in a clinical setting. Here, we describe a microfluidic assay that measures the spontaneous neutrophil migration signatures associated with sepsis. The assay uses one droplet of patient’s blood in a microfluidic device, which circumvents the need for neutrophil isolation from blood. This assay may also be useful for the study of the effect of various immune modulators on neutrophil migration behavior from healthy volunteers and patients.

Learn more

PUBLICATIONS

Characterizing well-differentiated culture of primary human nasal epithelial cells for use in wound healing assays

The nasal epithelium is the initial contact between the external environment and the respiratory tract and how it responds to noxious stimuli and repairs epithelial damage is important. Growing airway epithelial cells in culture at air-liquid interface allows for a physiologically relevant model of the human upper airways. The aim of the present study was to characterize human primary nasal epithelial cells grown at the air-liquid interface and establish a model for use in wound healing assays. This study determined the time required for full differentiation of nasal epithelial cells in an air-liquid interface culture to be at least 7 weeks using the standardized B-ALI media. Also, a model was established that studied the response to wounding and the effect of EGFR inhibition on this process. Nasal epithelial cultures from healthy subjects were differentiated at air-liquid interface and manually wounded. Wounds were monitored over time to complete closure using a time lapse imaging microscope with cultures identified to have a rate of wound healing above 2.5%/h independent of initial wound size. EGFR inhibition caused the rate of wound healing to drop a significant 4.6%/h with there being no closure of the wound after 48 h. The robust model established in this study will be essential for studying factors influencing wound healing, including host disease status and environmental exposures in the future.

Learn more

PUBLICATIONS

lH-Pyrazolo[3,4-b]quinolin-3-amine derivatives inhibit growth of colon cancer cells via apoptosis and sub G1 cell cycle arrest

A series of lH-pyrazolo[3,4-b]quinolin-3-amine derivatives were synthesized and evaluated for anticancer efficacy in a panel of ten cancer cell lines, including breast (MDAMB-231 and MCF-7), colon (HCT-116, HCT-15, HT-29 and LOVO), prostate (DU-145 and PC3), brain (LN-229), ovarian (A2780), and human embryonic kidney (HEK293) cells, a non-cancerous cell line. Among the eight derivatives screened, compound QTZ05 had the most potent and selective antitumor efficacy in the four colon cancer cell lines, with IC50 values ranging from 2.3 to 10.2 µM. Furthermore, QTZ05 inhibited colony formation in HCT-116 cells in a concentration-dependent manner. Cell cycle analysis data indicated that QTZ05 caused an arrest in the sub G1 cell cycle in HCT-116 cells. QTZ05 induced apoptosis in HCT-116 cells in a concentration-dependent manner that was characterized by chromatin condensation and increase in the fluorescence of fluorochrome-conjugated Annexin V. The findings from our study suggest that QTZ05 may be a valuable prototype for the development of chemotherapeutics targeting apoptotic pathways in colorectal cancer cells.

Learn more
Sign up now

Want to stay up to date? Sign up for our newsletter

No, thanks