Establishment and evaluation of immortalized human epidermal keratinocytes for an alternative skin irritation test

Different immortalized keratinocyte cell lines display distinct capabilities to differentiate and reconstitute an epidermis in vitro

Dermatological research relies on the availability of suitable models that most accurately reflect the in vivo situation. Primary keratinocytes obtained from skin reduction surgeries are not only limited by availability but have a short lifespan and show donor-specific variations, which hamper the understanding of general mechanisms. The spontaneously immortalized keratinocyte cell line HaCaT displays chromosomal aberrations and is known to differentiate in an abnormal manner. To overcome these issues, we validated different engineered immortalized cell lines created from primary human keratinocytes (NHK) as model systems to study epidermal function. Cell lines either immortalized by the expression of SV40 large T antigen and hTERT (NHK-SV/TERT) or by transduction with HPV E6/E7 (NHK-E6/E7) were analysed for their growth and differentiation behaviour using 2D and 3D culture systems and compared to primary keratinocytes. Both cell lines displayed a robust proliferative behaviour but were still sensitive to contact inhibition. NHK-E6/E7 could be driven into differentiation by Ca2+ switch, while NHK-SV/TERT needed withdrawal from any proliferative signal to initiate a delayed onset of differentiation. In 3D epidermal models both cell lines were able to reconstitute a stratified epidermis and functional epidermal barrier. However, only NHK-E6/E7 showed a degree of epidermal maturation and stratification that was comparable to primary keratinocytes.

Overexpression of KiSS1 Induces the Proliferation of Hepatocarcinoma and Increases Metastatic Potential by Increasing Migratory Ability and Angiogenic Capacity

Liver cancer has a high prevalence, with majority of the cases presenting as hepatocellular carcinoma (HCC). The prognosis of metastatic HCC has hardly improved over the past decade, highlighting the necessity for liver cancer research. Studies have reported the ability of the KiSS1 gene to inhibit the growth or metastasis of liver cancer, but contradictory research results are also emerging. We, therefore, sought to investigate the effects of KiSS1 on growth and migration in human HCC cells. HepG2 human HCC cells were infected with lentivirus particles containing KiSS1. The overexpression of KiSS1 resulted in an increased proliferation rate of HCC cells. Quantitative polymerase chain reaction and immunoblotting revealed increased Akt activity, and downregulation of the G1/S phase cell cycle inhibitors. A significant increase in tumor spheroid formation with upregulation of β-catenin and CD133 was also observed. KiSS1 overexpression promoted the migratory, invasive ability, and metastatic capacity of the hepatocarcinoma cell line, and these effects were associated with changes in the expressions of epithelial mesenchymal transition (EMT)-related genes such as E-cadherin, N-cadherin, and slug. KiSS1 overexpression also resulted in dramatically increased tumor growth in the xenograft mouse model, and upregulation of proliferating cell nuclear antigen (PCNA) and Ki-67 in the HCC tumors. Furthermore, KiSS1 increased the angiogenic capacity by upregulation of the vascular endothelial growth factor A (VEGF-A) and CD31. Based on these observations, we infer that KiSS1 not only induces HCC proliferation, but also increases the metastatic potential by increasing the migratory ability and angiogenic capacity.

The role of KiSS1 gene on the growth and migration of prostate cancer and the underlying molecular mechanisms

Metastatic prostate cancers have a high mortality rate. KiSS1 was originally identified as a metastasis suppressor gene in metastatic melanoma and breast cancer, but its role in prostate cancer has been contradictory. This study was therefore undertaken to investigate the effects of KiSS1 overexpression on the growth and migration of human metastatic prostate cancer cells. We first tested the effect of KiSS1 overexpression on the growth and migration of DU145 human metastatic prostate cancer cells in vitro. DU145 cells were infected with the culture medium of 293T cells, which produce lentivirus particles containing KiSS1. A 2.5-fold increase in proliferation of KiSS1-overexpressing cancer cells was observed, and these cells formed tumor spheroids about 3 times larger than the vector control group. qPCR and immunoblotting revealed the association between increased cell growth and regulation of the PI3K/Akt and cell cycle genes, and also that increases in β-catenin and CD133 contribute to tumor aggregation. KiSS1 overexpression resulted in upregulation of the β-arrestin1/2 and Raf-MEK-ERK-NF-κB pathways via KiSS1R. Moreover, the migration and invasion of KiSS1-overexpressing cells were determined to be faster than the control group, along with 1.6-fold increased metastatic colonization of the KiSS1-overexpressing cancer cells. These were associated to the regulation of EMT gene expressions, such as E-cadherin and N-cadherin, and the upregulation of MMP9. In a xenograft mouse model inoculated with DU145 cells infected GFP or KiSS1 via a lentiviral vector, KiSS1 statistically significantly increased the tumor growth, with upregulation of PCNA and Ki-67 in the tumor tissues. In addition, KiSS1 increased the angiogenic capacity by upregulating VEGF-A and CD31, both in vitro and in vivo. Taken together, our results indicate that KiSS1 not only induces prostate cancer proliferation, but also promotes metastasis by increasing the migration, invasion, and angiogenesis of malignant cells.

The role of biofilm formation in the pathogenesis and antimicrobial susceptibility of Cutibacterium acnes

Cutibacterium acnes (previously known as Propionibacterium acnes) is frequently found on lipid-rich parts of the human skin. While C. acnes is most known for its role in the development and progression of the skin disease acne, it is also involved in many other types of infections, often involving implanted medical devices. C. acnes readily forms biofilms in vitro and there is growing evidence that biofilm formation by this Gram-positive, facultative anaerobic micro-organism plays an important role in vivo and is also involved in treatment failure. In this brief review we present an overview on what is known about C. acnes biofilms (including their role in pathogenesis and reduced susceptibility to antibiotics), discuss model systems that can be used to study these biofilms in vitro and in vivo and give an overview of interspecies interactions occurring in polymicrobial communities containing C. acnes.

Anti-Irritant and Anti-Inflammatory Effects of DHA Encapsulated in Resveratrol-Based Solid Lipid Nanoparticles in Human Keratinocytes

We recently found that the dietary long chain omega-3 polyunsaturated fatty acid (LC-ω-3 PUFA), docosahexaenoic acid (DHA), showed enhanced antineoplastic activity against colon cancer cells if encapsulated in resveratrol-based solid lipid nanoparticles (RV-SLNs). In the present study, we investigated whether the DHA enclosed in RV-SLNs (DHA-RV-SLNs) could have the potential of attenuating irritation and inflammation caused by environmental factors at the skin level. To this aim, we used two keratinocyte lines (HaCaT and NCTC 2544 cells) and exposed them to the cytotoxic action of the surfactant, sodium dodecyl sulfate (SDS), as an in vitro model of irritation, or to the pro-inflammatory activity of the cytokine TNF-α. We found that DHA enclosed in RV-SLNs significantly enhanced its ability to contrast the cytotoxic effect of SDS and to inhibit the SDS- and TNF-α-induced production of the inflammatory cytokines IL-1β, IL-6, and 1 MCP-1, in the two keratinocyte cell lines, as well as the NLRP3 inflammasome activation. Moreover, it more efficiently reduced the upsurge of reactive oxygen species (ROS) levels obtained in the presence of a pro-oxidant (H₂O₂). Overall, our findings suggest the possibility that a sustained dietary supplementation with DHA-RV-SLNs could efficiently protect skin from the pro-irritant and pro-inflammatory activity of environmental attacks.

Establishment of an immortalized human subglottic epithelial cell line

Objective

Translational research into subglottic disease is restricted by the availability of primary human tissue originating from this subsite. Primary epithelial cells are also limited by their inability to survive beyond several divisions in culture outside of the body. Specific subglottic cell lines, useful for in vitro studies, have not yet been described. We therefore demonstrate what we believe to be the first immortalized subglottic epithelial cell line.

Methods

Subglottic tissue was derived from a single adult patient's neoplasia‐free human subglottic brushing specimen. Cells were immortalized using a lentiviral vector expressing simian virus 40 T antigen. Karyotyping was performed on the transformed cells using single nucleotide polymorphism array comparative genomic hybridization. Transformed cells were phenotypically characterized by light microscopy, immunohistochemistry, and electrophysiology studies.

Results

The immortalized subglottic cell line (SG01) was able to divide successfully beyond 20 passages. Karyotyping demonstrated no significant genomic imbalance after immortalization. The cells demonstrated normal epithelial morphology and cytokeratin expression throughout. SG01 cells were also successfully cultured at air–liquid interface (ALI). At ALI cells demonstrated cilia, mucus production, and relevant ion channel expression.

Conclusion

The novel SG01 subglottic epithelial cell line has been established. This cell line provides a unique resource for researchers to investigate subglottic diseases, such as subglottic stenosis.

Level of Evidence

NA. Laryngoscope, 129:2640–2645, 2019

Establishment of five immortalized human ovarian surface epithelial cell lines via SV40 T antigen or HPV E6/E7 expression

Background

Human ovarian surface epithelial (HOSE) cells are a critical cell source for ovarian cancer research; however, they are difficult to obtain and maintain under standard laboratory conditions in large quantities. The aim of this study was to generate immortalized HOSE (IHOSE) cells with maintained properties to the original cell source, thereby guaranteeing a sufficiently large cell quantity for ovarian cancer research.

Methods

HOSE cells isolated from four non-cancer patients and five IHOSE cell lines were established by induction of HPV-E6/E7 expression or SV40 large T antigen using a lenti-viral system. Each of IHOSE cells was confirmed to be distinct by STR profiling. RNA-sequencing was used to compare gene expression profiles in HOSE, IHOSE and ovarian cancer cells.

Results

RNA-sequencing results revealed a stronger linear correlation in gene expression between IHOSE and HOSE cells (R² = 0.9288) than between IHOSE or HOSE cells and ovarian cancer cells (R² = 0.8562 and R² = 0.7982, respectively). The gene expression pattern of 319 differentially expressed genes revealed minimal differences between HOSE and IHOSE cells, while a strong difference between ovarian cancer cells and HOSE or IHOSE cells was observed. Furthermore, the five IHOSE cell lines displayed morphological characteristics typical of epithelial cells but showed a lower level of EpCAM, CD133 and E-cadherin, as cancer stem marker, than ovarian cancer cells. Moreover, unlike cancer cells, IHOSE cells could not form colonies in the anchorage-independent soft agar growth assay.

Conclusion

These findings demonstrate that five newly established IHOSE cell lines have characteristics of progenitor HOSE cells while exhibiting continuous growth, and thus, should be highly useful as control cells for ovarian cancer research.